1 //===--- ExprConstant.cpp - Expression Constant Evaluator -----------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file implements the Expr constant evaluator. 10 // 11 // Constant expression evaluation produces four main results: 12 // 13 // * A success/failure flag indicating whether constant folding was successful. 14 // This is the 'bool' return value used by most of the code in this file. A 15 // 'false' return value indicates that constant folding has failed, and any 16 // appropriate diagnostic has already been produced. 17 // 18 // * An evaluated result, valid only if constant folding has not failed. 19 // 20 // * A flag indicating if evaluation encountered (unevaluated) side-effects. 21 // These arise in cases such as (sideEffect(), 0) and (sideEffect() || 1), 22 // where it is possible to determine the evaluated result regardless. 23 // 24 // * A set of notes indicating why the evaluation was not a constant expression 25 // (under the C++11 / C++1y rules only, at the moment), or, if folding failed 26 // too, why the expression could not be folded. 27 // 28 // If we are checking for a potential constant expression, failure to constant 29 // fold a potential constant sub-expression will be indicated by a 'false' 30 // return value (the expression could not be folded) and no diagnostic (the 31 // expression is not necessarily non-constant). 32 // 33 //===----------------------------------------------------------------------===// 34 35 #include "Interp/Context.h" 36 #include "Interp/Frame.h" 37 #include "Interp/State.h" 38 #include "clang/AST/APValue.h" 39 #include "clang/AST/ASTContext.h" 40 #include "clang/AST/ASTDiagnostic.h" 41 #include "clang/AST/ASTLambda.h" 42 #include "clang/AST/Attr.h" 43 #include "clang/AST/CXXInheritance.h" 44 #include "clang/AST/CharUnits.h" 45 #include "clang/AST/CurrentSourceLocExprScope.h" 46 #include "clang/AST/Expr.h" 47 #include "clang/AST/OSLog.h" 48 #include "clang/AST/OptionalDiagnostic.h" 49 #include "clang/AST/RecordLayout.h" 50 #include "clang/AST/StmtVisitor.h" 51 #include "clang/AST/TypeLoc.h" 52 #include "clang/Basic/Builtins.h" 53 #include "clang/Basic/FixedPoint.h" 54 #include "clang/Basic/TargetInfo.h" 55 #include "llvm/ADT/Optional.h" 56 #include "llvm/ADT/SmallBitVector.h" 57 #include "llvm/Support/Debug.h" 58 #include "llvm/Support/SaveAndRestore.h" 59 #include "llvm/Support/raw_ostream.h" 60 #include <cstring> 61 #include <functional> 62 63 #define DEBUG_TYPE "exprconstant" 64 65 using namespace clang; 66 using llvm::APInt; 67 using llvm::APSInt; 68 using llvm::APFloat; 69 using llvm::Optional; 70 71 namespace { 72 struct LValue; 73 class CallStackFrame; 74 class EvalInfo; 75 76 using SourceLocExprScopeGuard = 77 CurrentSourceLocExprScope::SourceLocExprScopeGuard; 78 79 static QualType getType(APValue::LValueBase B) { 80 if (!B) return QualType(); 81 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) { 82 // FIXME: It's unclear where we're supposed to take the type from, and 83 // this actually matters for arrays of unknown bound. Eg: 84 // 85 // extern int arr[]; void f() { extern int arr[3]; }; 86 // constexpr int *p = &arr[1]; // valid? 87 // 88 // For now, we take the array bound from the most recent declaration. 89 for (auto *Redecl = cast<ValueDecl>(D->getMostRecentDecl()); Redecl; 90 Redecl = cast_or_null<ValueDecl>(Redecl->getPreviousDecl())) { 91 QualType T = Redecl->getType(); 92 if (!T->isIncompleteArrayType()) 93 return T; 94 } 95 return D->getType(); 96 } 97 98 if (B.is<TypeInfoLValue>()) 99 return B.getTypeInfoType(); 100 101 if (B.is<DynamicAllocLValue>()) 102 return B.getDynamicAllocType(); 103 104 const Expr *Base = B.get<const Expr*>(); 105 106 // For a materialized temporary, the type of the temporary we materialized 107 // may not be the type of the expression. 108 if (const MaterializeTemporaryExpr *MTE = 109 dyn_cast<MaterializeTemporaryExpr>(Base)) { 110 SmallVector<const Expr *, 2> CommaLHSs; 111 SmallVector<SubobjectAdjustment, 2> Adjustments; 112 const Expr *Temp = MTE->getSubExpr(); 113 const Expr *Inner = Temp->skipRValueSubobjectAdjustments(CommaLHSs, 114 Adjustments); 115 // Keep any cv-qualifiers from the reference if we generated a temporary 116 // for it directly. Otherwise use the type after adjustment. 117 if (!Adjustments.empty()) 118 return Inner->getType(); 119 } 120 121 return Base->getType(); 122 } 123 124 /// Get an LValue path entry, which is known to not be an array index, as a 125 /// field declaration. 126 static const FieldDecl *getAsField(APValue::LValuePathEntry E) { 127 return dyn_cast_or_null<FieldDecl>(E.getAsBaseOrMember().getPointer()); 128 } 129 /// Get an LValue path entry, which is known to not be an array index, as a 130 /// base class declaration. 131 static const CXXRecordDecl *getAsBaseClass(APValue::LValuePathEntry E) { 132 return dyn_cast_or_null<CXXRecordDecl>(E.getAsBaseOrMember().getPointer()); 133 } 134 /// Determine whether this LValue path entry for a base class names a virtual 135 /// base class. 136 static bool isVirtualBaseClass(APValue::LValuePathEntry E) { 137 return E.getAsBaseOrMember().getInt(); 138 } 139 140 /// Given an expression, determine the type used to store the result of 141 /// evaluating that expression. 142 static QualType getStorageType(const ASTContext &Ctx, const Expr *E) { 143 if (E->isRValue()) 144 return E->getType(); 145 return Ctx.getLValueReferenceType(E->getType()); 146 } 147 148 /// Given a CallExpr, try to get the alloc_size attribute. May return null. 149 static const AllocSizeAttr *getAllocSizeAttr(const CallExpr *CE) { 150 const FunctionDecl *Callee = CE->getDirectCallee(); 151 return Callee ? Callee->getAttr<AllocSizeAttr>() : nullptr; 152 } 153 154 /// Attempts to unwrap a CallExpr (with an alloc_size attribute) from an Expr. 155 /// This will look through a single cast. 156 /// 157 /// Returns null if we couldn't unwrap a function with alloc_size. 158 static const CallExpr *tryUnwrapAllocSizeCall(const Expr *E) { 159 if (!E->getType()->isPointerType()) 160 return nullptr; 161 162 E = E->IgnoreParens(); 163 // If we're doing a variable assignment from e.g. malloc(N), there will 164 // probably be a cast of some kind. In exotic cases, we might also see a 165 // top-level ExprWithCleanups. Ignore them either way. 166 if (const auto *FE = dyn_cast<FullExpr>(E)) 167 E = FE->getSubExpr()->IgnoreParens(); 168 169 if (const auto *Cast = dyn_cast<CastExpr>(E)) 170 E = Cast->getSubExpr()->IgnoreParens(); 171 172 if (const auto *CE = dyn_cast<CallExpr>(E)) 173 return getAllocSizeAttr(CE) ? CE : nullptr; 174 return nullptr; 175 } 176 177 /// Determines whether or not the given Base contains a call to a function 178 /// with the alloc_size attribute. 179 static bool isBaseAnAllocSizeCall(APValue::LValueBase Base) { 180 const auto *E = Base.dyn_cast<const Expr *>(); 181 return E && E->getType()->isPointerType() && tryUnwrapAllocSizeCall(E); 182 } 183 184 /// The bound to claim that an array of unknown bound has. 185 /// The value in MostDerivedArraySize is undefined in this case. So, set it 186 /// to an arbitrary value that's likely to loudly break things if it's used. 187 static const uint64_t AssumedSizeForUnsizedArray = 188 std::numeric_limits<uint64_t>::max() / 2; 189 190 /// Determines if an LValue with the given LValueBase will have an unsized 191 /// array in its designator. 192 /// Find the path length and type of the most-derived subobject in the given 193 /// path, and find the size of the containing array, if any. 194 static unsigned 195 findMostDerivedSubobject(ASTContext &Ctx, APValue::LValueBase Base, 196 ArrayRef<APValue::LValuePathEntry> Path, 197 uint64_t &ArraySize, QualType &Type, bool &IsArray, 198 bool &FirstEntryIsUnsizedArray) { 199 // This only accepts LValueBases from APValues, and APValues don't support 200 // arrays that lack size info. 201 assert(!isBaseAnAllocSizeCall(Base) && 202 "Unsized arrays shouldn't appear here"); 203 unsigned MostDerivedLength = 0; 204 Type = getType(Base); 205 206 for (unsigned I = 0, N = Path.size(); I != N; ++I) { 207 if (Type->isArrayType()) { 208 const ArrayType *AT = Ctx.getAsArrayType(Type); 209 Type = AT->getElementType(); 210 MostDerivedLength = I + 1; 211 IsArray = true; 212 213 if (auto *CAT = dyn_cast<ConstantArrayType>(AT)) { 214 ArraySize = CAT->getSize().getZExtValue(); 215 } else { 216 assert(I == 0 && "unexpected unsized array designator"); 217 FirstEntryIsUnsizedArray = true; 218 ArraySize = AssumedSizeForUnsizedArray; 219 } 220 } else if (Type->isAnyComplexType()) { 221 const ComplexType *CT = Type->castAs<ComplexType>(); 222 Type = CT->getElementType(); 223 ArraySize = 2; 224 MostDerivedLength = I + 1; 225 IsArray = true; 226 } else if (const FieldDecl *FD = getAsField(Path[I])) { 227 Type = FD->getType(); 228 ArraySize = 0; 229 MostDerivedLength = I + 1; 230 IsArray = false; 231 } else { 232 // Path[I] describes a base class. 233 ArraySize = 0; 234 IsArray = false; 235 } 236 } 237 return MostDerivedLength; 238 } 239 240 /// A path from a glvalue to a subobject of that glvalue. 241 struct SubobjectDesignator { 242 /// True if the subobject was named in a manner not supported by C++11. Such 243 /// lvalues can still be folded, but they are not core constant expressions 244 /// and we cannot perform lvalue-to-rvalue conversions on them. 245 unsigned Invalid : 1; 246 247 /// Is this a pointer one past the end of an object? 248 unsigned IsOnePastTheEnd : 1; 249 250 /// Indicator of whether the first entry is an unsized array. 251 unsigned FirstEntryIsAnUnsizedArray : 1; 252 253 /// Indicator of whether the most-derived object is an array element. 254 unsigned MostDerivedIsArrayElement : 1; 255 256 /// The length of the path to the most-derived object of which this is a 257 /// subobject. 258 unsigned MostDerivedPathLength : 28; 259 260 /// The size of the array of which the most-derived object is an element. 261 /// This will always be 0 if the most-derived object is not an array 262 /// element. 0 is not an indicator of whether or not the most-derived object 263 /// is an array, however, because 0-length arrays are allowed. 264 /// 265 /// If the current array is an unsized array, the value of this is 266 /// undefined. 267 uint64_t MostDerivedArraySize; 268 269 /// The type of the most derived object referred to by this address. 270 QualType MostDerivedType; 271 272 typedef APValue::LValuePathEntry PathEntry; 273 274 /// The entries on the path from the glvalue to the designated subobject. 275 SmallVector<PathEntry, 8> Entries; 276 277 SubobjectDesignator() : Invalid(true) {} 278 279 explicit SubobjectDesignator(QualType T) 280 : Invalid(false), IsOnePastTheEnd(false), 281 FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false), 282 MostDerivedPathLength(0), MostDerivedArraySize(0), 283 MostDerivedType(T) {} 284 285 SubobjectDesignator(ASTContext &Ctx, const APValue &V) 286 : Invalid(!V.isLValue() || !V.hasLValuePath()), IsOnePastTheEnd(false), 287 FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false), 288 MostDerivedPathLength(0), MostDerivedArraySize(0) { 289 assert(V.isLValue() && "Non-LValue used to make an LValue designator?"); 290 if (!Invalid) { 291 IsOnePastTheEnd = V.isLValueOnePastTheEnd(); 292 ArrayRef<PathEntry> VEntries = V.getLValuePath(); 293 Entries.insert(Entries.end(), VEntries.begin(), VEntries.end()); 294 if (V.getLValueBase()) { 295 bool IsArray = false; 296 bool FirstIsUnsizedArray = false; 297 MostDerivedPathLength = findMostDerivedSubobject( 298 Ctx, V.getLValueBase(), V.getLValuePath(), MostDerivedArraySize, 299 MostDerivedType, IsArray, FirstIsUnsizedArray); 300 MostDerivedIsArrayElement = IsArray; 301 FirstEntryIsAnUnsizedArray = FirstIsUnsizedArray; 302 } 303 } 304 } 305 306 void truncate(ASTContext &Ctx, APValue::LValueBase Base, 307 unsigned NewLength) { 308 if (Invalid) 309 return; 310 311 assert(Base && "cannot truncate path for null pointer"); 312 assert(NewLength <= Entries.size() && "not a truncation"); 313 314 if (NewLength == Entries.size()) 315 return; 316 Entries.resize(NewLength); 317 318 bool IsArray = false; 319 bool FirstIsUnsizedArray = false; 320 MostDerivedPathLength = findMostDerivedSubobject( 321 Ctx, Base, Entries, MostDerivedArraySize, MostDerivedType, IsArray, 322 FirstIsUnsizedArray); 323 MostDerivedIsArrayElement = IsArray; 324 FirstEntryIsAnUnsizedArray = FirstIsUnsizedArray; 325 } 326 327 void setInvalid() { 328 Invalid = true; 329 Entries.clear(); 330 } 331 332 /// Determine whether the most derived subobject is an array without a 333 /// known bound. 334 bool isMostDerivedAnUnsizedArray() const { 335 assert(!Invalid && "Calling this makes no sense on invalid designators"); 336 return Entries.size() == 1 && FirstEntryIsAnUnsizedArray; 337 } 338 339 /// Determine what the most derived array's size is. Results in an assertion 340 /// failure if the most derived array lacks a size. 341 uint64_t getMostDerivedArraySize() const { 342 assert(!isMostDerivedAnUnsizedArray() && "Unsized array has no size"); 343 return MostDerivedArraySize; 344 } 345 346 /// Determine whether this is a one-past-the-end pointer. 347 bool isOnePastTheEnd() const { 348 assert(!Invalid); 349 if (IsOnePastTheEnd) 350 return true; 351 if (!isMostDerivedAnUnsizedArray() && MostDerivedIsArrayElement && 352 Entries[MostDerivedPathLength - 1].getAsArrayIndex() == 353 MostDerivedArraySize) 354 return true; 355 return false; 356 } 357 358 /// Get the range of valid index adjustments in the form 359 /// {maximum value that can be subtracted from this pointer, 360 /// maximum value that can be added to this pointer} 361 std::pair<uint64_t, uint64_t> validIndexAdjustments() { 362 if (Invalid || isMostDerivedAnUnsizedArray()) 363 return {0, 0}; 364 365 // [expr.add]p4: For the purposes of these operators, a pointer to a 366 // nonarray object behaves the same as a pointer to the first element of 367 // an array of length one with the type of the object as its element type. 368 bool IsArray = MostDerivedPathLength == Entries.size() && 369 MostDerivedIsArrayElement; 370 uint64_t ArrayIndex = IsArray ? Entries.back().getAsArrayIndex() 371 : (uint64_t)IsOnePastTheEnd; 372 uint64_t ArraySize = 373 IsArray ? getMostDerivedArraySize() : (uint64_t)1; 374 return {ArrayIndex, ArraySize - ArrayIndex}; 375 } 376 377 /// Check that this refers to a valid subobject. 378 bool isValidSubobject() const { 379 if (Invalid) 380 return false; 381 return !isOnePastTheEnd(); 382 } 383 /// Check that this refers to a valid subobject, and if not, produce a 384 /// relevant diagnostic and set the designator as invalid. 385 bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK); 386 387 /// Get the type of the designated object. 388 QualType getType(ASTContext &Ctx) const { 389 assert(!Invalid && "invalid designator has no subobject type"); 390 return MostDerivedPathLength == Entries.size() 391 ? MostDerivedType 392 : Ctx.getRecordType(getAsBaseClass(Entries.back())); 393 } 394 395 /// Update this designator to refer to the first element within this array. 396 void addArrayUnchecked(const ConstantArrayType *CAT) { 397 Entries.push_back(PathEntry::ArrayIndex(0)); 398 399 // This is a most-derived object. 400 MostDerivedType = CAT->getElementType(); 401 MostDerivedIsArrayElement = true; 402 MostDerivedArraySize = CAT->getSize().getZExtValue(); 403 MostDerivedPathLength = Entries.size(); 404 } 405 /// Update this designator to refer to the first element within the array of 406 /// elements of type T. This is an array of unknown size. 407 void addUnsizedArrayUnchecked(QualType ElemTy) { 408 Entries.push_back(PathEntry::ArrayIndex(0)); 409 410 MostDerivedType = ElemTy; 411 MostDerivedIsArrayElement = true; 412 // The value in MostDerivedArraySize is undefined in this case. So, set it 413 // to an arbitrary value that's likely to loudly break things if it's 414 // used. 415 MostDerivedArraySize = AssumedSizeForUnsizedArray; 416 MostDerivedPathLength = Entries.size(); 417 } 418 /// Update this designator to refer to the given base or member of this 419 /// object. 420 void addDeclUnchecked(const Decl *D, bool Virtual = false) { 421 Entries.push_back(APValue::BaseOrMemberType(D, Virtual)); 422 423 // If this isn't a base class, it's a new most-derived object. 424 if (const FieldDecl *FD = dyn_cast<FieldDecl>(D)) { 425 MostDerivedType = FD->getType(); 426 MostDerivedIsArrayElement = false; 427 MostDerivedArraySize = 0; 428 MostDerivedPathLength = Entries.size(); 429 } 430 } 431 /// Update this designator to refer to the given complex component. 432 void addComplexUnchecked(QualType EltTy, bool Imag) { 433 Entries.push_back(PathEntry::ArrayIndex(Imag)); 434 435 // This is technically a most-derived object, though in practice this 436 // is unlikely to matter. 437 MostDerivedType = EltTy; 438 MostDerivedIsArrayElement = true; 439 MostDerivedArraySize = 2; 440 MostDerivedPathLength = Entries.size(); 441 } 442 void diagnoseUnsizedArrayPointerArithmetic(EvalInfo &Info, const Expr *E); 443 void diagnosePointerArithmetic(EvalInfo &Info, const Expr *E, 444 const APSInt &N); 445 /// Add N to the address of this subobject. 446 void adjustIndex(EvalInfo &Info, const Expr *E, APSInt N) { 447 if (Invalid || !N) return; 448 uint64_t TruncatedN = N.extOrTrunc(64).getZExtValue(); 449 if (isMostDerivedAnUnsizedArray()) { 450 diagnoseUnsizedArrayPointerArithmetic(Info, E); 451 // Can't verify -- trust that the user is doing the right thing (or if 452 // not, trust that the caller will catch the bad behavior). 453 // FIXME: Should we reject if this overflows, at least? 454 Entries.back() = PathEntry::ArrayIndex( 455 Entries.back().getAsArrayIndex() + TruncatedN); 456 return; 457 } 458 459 // [expr.add]p4: For the purposes of these operators, a pointer to a 460 // nonarray object behaves the same as a pointer to the first element of 461 // an array of length one with the type of the object as its element type. 462 bool IsArray = MostDerivedPathLength == Entries.size() && 463 MostDerivedIsArrayElement; 464 uint64_t ArrayIndex = IsArray ? Entries.back().getAsArrayIndex() 465 : (uint64_t)IsOnePastTheEnd; 466 uint64_t ArraySize = 467 IsArray ? getMostDerivedArraySize() : (uint64_t)1; 468 469 if (N < -(int64_t)ArrayIndex || N > ArraySize - ArrayIndex) { 470 // Calculate the actual index in a wide enough type, so we can include 471 // it in the note. 472 N = N.extend(std::max<unsigned>(N.getBitWidth() + 1, 65)); 473 (llvm::APInt&)N += ArrayIndex; 474 assert(N.ugt(ArraySize) && "bounds check failed for in-bounds index"); 475 diagnosePointerArithmetic(Info, E, N); 476 setInvalid(); 477 return; 478 } 479 480 ArrayIndex += TruncatedN; 481 assert(ArrayIndex <= ArraySize && 482 "bounds check succeeded for out-of-bounds index"); 483 484 if (IsArray) 485 Entries.back() = PathEntry::ArrayIndex(ArrayIndex); 486 else 487 IsOnePastTheEnd = (ArrayIndex != 0); 488 } 489 }; 490 491 /// A stack frame in the constexpr call stack. 492 class CallStackFrame : public interp::Frame { 493 public: 494 EvalInfo &Info; 495 496 /// Parent - The caller of this stack frame. 497 CallStackFrame *Caller; 498 499 /// Callee - The function which was called. 500 const FunctionDecl *Callee; 501 502 /// This - The binding for the this pointer in this call, if any. 503 const LValue *This; 504 505 /// Arguments - Parameter bindings for this function call, indexed by 506 /// parameters' function scope indices. 507 APValue *Arguments; 508 509 /// Source location information about the default argument or default 510 /// initializer expression we're evaluating, if any. 511 CurrentSourceLocExprScope CurSourceLocExprScope; 512 513 // Note that we intentionally use std::map here so that references to 514 // values are stable. 515 typedef std::pair<const void *, unsigned> MapKeyTy; 516 typedef std::map<MapKeyTy, APValue> MapTy; 517 /// Temporaries - Temporary lvalues materialized within this stack frame. 518 MapTy Temporaries; 519 520 /// CallLoc - The location of the call expression for this call. 521 SourceLocation CallLoc; 522 523 /// Index - The call index of this call. 524 unsigned Index; 525 526 /// The stack of integers for tracking version numbers for temporaries. 527 SmallVector<unsigned, 2> TempVersionStack = {1}; 528 unsigned CurTempVersion = TempVersionStack.back(); 529 530 unsigned getTempVersion() const { return TempVersionStack.back(); } 531 532 void pushTempVersion() { 533 TempVersionStack.push_back(++CurTempVersion); 534 } 535 536 void popTempVersion() { 537 TempVersionStack.pop_back(); 538 } 539 540 // FIXME: Adding this to every 'CallStackFrame' may have a nontrivial impact 541 // on the overall stack usage of deeply-recursing constexpr evaluations. 542 // (We should cache this map rather than recomputing it repeatedly.) 543 // But let's try this and see how it goes; we can look into caching the map 544 // as a later change. 545 546 /// LambdaCaptureFields - Mapping from captured variables/this to 547 /// corresponding data members in the closure class. 548 llvm::DenseMap<const VarDecl *, FieldDecl *> LambdaCaptureFields; 549 FieldDecl *LambdaThisCaptureField; 550 551 CallStackFrame(EvalInfo &Info, SourceLocation CallLoc, 552 const FunctionDecl *Callee, const LValue *This, 553 APValue *Arguments); 554 ~CallStackFrame(); 555 556 // Return the temporary for Key whose version number is Version. 557 APValue *getTemporary(const void *Key, unsigned Version) { 558 MapKeyTy KV(Key, Version); 559 auto LB = Temporaries.lower_bound(KV); 560 if (LB != Temporaries.end() && LB->first == KV) 561 return &LB->second; 562 // Pair (Key,Version) wasn't found in the map. Check that no elements 563 // in the map have 'Key' as their key. 564 assert((LB == Temporaries.end() || LB->first.first != Key) && 565 (LB == Temporaries.begin() || std::prev(LB)->first.first != Key) && 566 "Element with key 'Key' found in map"); 567 return nullptr; 568 } 569 570 // Return the current temporary for Key in the map. 571 APValue *getCurrentTemporary(const void *Key) { 572 auto UB = Temporaries.upper_bound(MapKeyTy(Key, UINT_MAX)); 573 if (UB != Temporaries.begin() && std::prev(UB)->first.first == Key) 574 return &std::prev(UB)->second; 575 return nullptr; 576 } 577 578 // Return the version number of the current temporary for Key. 579 unsigned getCurrentTemporaryVersion(const void *Key) const { 580 auto UB = Temporaries.upper_bound(MapKeyTy(Key, UINT_MAX)); 581 if (UB != Temporaries.begin() && std::prev(UB)->first.first == Key) 582 return std::prev(UB)->first.second; 583 return 0; 584 } 585 586 /// Allocate storage for an object of type T in this stack frame. 587 /// Populates LV with a handle to the created object. Key identifies 588 /// the temporary within the stack frame, and must not be reused without 589 /// bumping the temporary version number. 590 template<typename KeyT> 591 APValue &createTemporary(const KeyT *Key, QualType T, 592 bool IsLifetimeExtended, LValue &LV); 593 594 void describe(llvm::raw_ostream &OS) override; 595 596 Frame *getCaller() const override { return Caller; } 597 SourceLocation getCallLocation() const override { return CallLoc; } 598 const FunctionDecl *getCallee() const override { return Callee; } 599 600 bool isStdFunction() const { 601 for (const DeclContext *DC = Callee; DC; DC = DC->getParent()) 602 if (DC->isStdNamespace()) 603 return true; 604 return false; 605 } 606 }; 607 608 /// Temporarily override 'this'. 609 class ThisOverrideRAII { 610 public: 611 ThisOverrideRAII(CallStackFrame &Frame, const LValue *NewThis, bool Enable) 612 : Frame(Frame), OldThis(Frame.This) { 613 if (Enable) 614 Frame.This = NewThis; 615 } 616 ~ThisOverrideRAII() { 617 Frame.This = OldThis; 618 } 619 private: 620 CallStackFrame &Frame; 621 const LValue *OldThis; 622 }; 623 } 624 625 static bool HandleDestruction(EvalInfo &Info, const Expr *E, 626 const LValue &This, QualType ThisType); 627 static bool HandleDestruction(EvalInfo &Info, SourceLocation Loc, 628 APValue::LValueBase LVBase, APValue &Value, 629 QualType T); 630 631 namespace { 632 /// A cleanup, and a flag indicating whether it is lifetime-extended. 633 class Cleanup { 634 llvm::PointerIntPair<APValue*, 1, bool> Value; 635 APValue::LValueBase Base; 636 QualType T; 637 638 public: 639 Cleanup(APValue *Val, APValue::LValueBase Base, QualType T, 640 bool IsLifetimeExtended) 641 : Value(Val, IsLifetimeExtended), Base(Base), T(T) {} 642 643 bool isLifetimeExtended() const { return Value.getInt(); } 644 bool endLifetime(EvalInfo &Info, bool RunDestructors) { 645 if (RunDestructors) { 646 SourceLocation Loc; 647 if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>()) 648 Loc = VD->getLocation(); 649 else if (const Expr *E = Base.dyn_cast<const Expr*>()) 650 Loc = E->getExprLoc(); 651 return HandleDestruction(Info, Loc, Base, *Value.getPointer(), T); 652 } 653 *Value.getPointer() = APValue(); 654 return true; 655 } 656 657 bool hasSideEffect() { 658 return T.isDestructedType(); 659 } 660 }; 661 662 /// A reference to an object whose construction we are currently evaluating. 663 struct ObjectUnderConstruction { 664 APValue::LValueBase Base; 665 ArrayRef<APValue::LValuePathEntry> Path; 666 friend bool operator==(const ObjectUnderConstruction &LHS, 667 const ObjectUnderConstruction &RHS) { 668 return LHS.Base == RHS.Base && LHS.Path == RHS.Path; 669 } 670 friend llvm::hash_code hash_value(const ObjectUnderConstruction &Obj) { 671 return llvm::hash_combine(Obj.Base, Obj.Path); 672 } 673 }; 674 enum class ConstructionPhase { 675 None, 676 Bases, 677 AfterBases, 678 AfterFields, 679 Destroying, 680 DestroyingBases 681 }; 682 } 683 684 namespace llvm { 685 template<> struct DenseMapInfo<ObjectUnderConstruction> { 686 using Base = DenseMapInfo<APValue::LValueBase>; 687 static ObjectUnderConstruction getEmptyKey() { 688 return {Base::getEmptyKey(), {}}; } 689 static ObjectUnderConstruction getTombstoneKey() { 690 return {Base::getTombstoneKey(), {}}; 691 } 692 static unsigned getHashValue(const ObjectUnderConstruction &Object) { 693 return hash_value(Object); 694 } 695 static bool isEqual(const ObjectUnderConstruction &LHS, 696 const ObjectUnderConstruction &RHS) { 697 return LHS == RHS; 698 } 699 }; 700 } 701 702 namespace { 703 /// A dynamically-allocated heap object. 704 struct DynAlloc { 705 /// The value of this heap-allocated object. 706 APValue Value; 707 /// The allocating expression; used for diagnostics. Either a CXXNewExpr 708 /// or a CallExpr (the latter is for direct calls to operator new inside 709 /// std::allocator<T>::allocate). 710 const Expr *AllocExpr = nullptr; 711 712 enum Kind { 713 New, 714 ArrayNew, 715 StdAllocator 716 }; 717 718 /// Get the kind of the allocation. This must match between allocation 719 /// and deallocation. 720 Kind getKind() const { 721 if (auto *NE = dyn_cast<CXXNewExpr>(AllocExpr)) 722 return NE->isArray() ? ArrayNew : New; 723 assert(isa<CallExpr>(AllocExpr)); 724 return StdAllocator; 725 } 726 }; 727 728 struct DynAllocOrder { 729 bool operator()(DynamicAllocLValue L, DynamicAllocLValue R) const { 730 return L.getIndex() < R.getIndex(); 731 } 732 }; 733 734 /// EvalInfo - This is a private struct used by the evaluator to capture 735 /// information about a subexpression as it is folded. It retains information 736 /// about the AST context, but also maintains information about the folded 737 /// expression. 738 /// 739 /// If an expression could be evaluated, it is still possible it is not a C 740 /// "integer constant expression" or constant expression. If not, this struct 741 /// captures information about how and why not. 742 /// 743 /// One bit of information passed *into* the request for constant folding 744 /// indicates whether the subexpression is "evaluated" or not according to C 745 /// rules. For example, the RHS of (0 && foo()) is not evaluated. We can 746 /// evaluate the expression regardless of what the RHS is, but C only allows 747 /// certain things in certain situations. 748 class EvalInfo : public interp::State { 749 public: 750 ASTContext &Ctx; 751 752 /// EvalStatus - Contains information about the evaluation. 753 Expr::EvalStatus &EvalStatus; 754 755 /// CurrentCall - The top of the constexpr call stack. 756 CallStackFrame *CurrentCall; 757 758 /// CallStackDepth - The number of calls in the call stack right now. 759 unsigned CallStackDepth; 760 761 /// NextCallIndex - The next call index to assign. 762 unsigned NextCallIndex; 763 764 /// StepsLeft - The remaining number of evaluation steps we're permitted 765 /// to perform. This is essentially a limit for the number of statements 766 /// we will evaluate. 767 unsigned StepsLeft; 768 769 /// Enable the experimental new constant interpreter. If an expression is 770 /// not supported by the interpreter, an error is triggered. 771 bool EnableNewConstInterp; 772 773 /// BottomFrame - The frame in which evaluation started. This must be 774 /// initialized after CurrentCall and CallStackDepth. 775 CallStackFrame BottomFrame; 776 777 /// A stack of values whose lifetimes end at the end of some surrounding 778 /// evaluation frame. 779 llvm::SmallVector<Cleanup, 16> CleanupStack; 780 781 /// EvaluatingDecl - This is the declaration whose initializer is being 782 /// evaluated, if any. 783 APValue::LValueBase EvaluatingDecl; 784 785 enum class EvaluatingDeclKind { 786 None, 787 /// We're evaluating the construction of EvaluatingDecl. 788 Ctor, 789 /// We're evaluating the destruction of EvaluatingDecl. 790 Dtor, 791 }; 792 EvaluatingDeclKind IsEvaluatingDecl = EvaluatingDeclKind::None; 793 794 /// EvaluatingDeclValue - This is the value being constructed for the 795 /// declaration whose initializer is being evaluated, if any. 796 APValue *EvaluatingDeclValue; 797 798 /// Set of objects that are currently being constructed. 799 llvm::DenseMap<ObjectUnderConstruction, ConstructionPhase> 800 ObjectsUnderConstruction; 801 802 /// Current heap allocations, along with the location where each was 803 /// allocated. We use std::map here because we need stable addresses 804 /// for the stored APValues. 805 std::map<DynamicAllocLValue, DynAlloc, DynAllocOrder> HeapAllocs; 806 807 /// The number of heap allocations performed so far in this evaluation. 808 unsigned NumHeapAllocs = 0; 809 810 struct EvaluatingConstructorRAII { 811 EvalInfo &EI; 812 ObjectUnderConstruction Object; 813 bool DidInsert; 814 EvaluatingConstructorRAII(EvalInfo &EI, ObjectUnderConstruction Object, 815 bool HasBases) 816 : EI(EI), Object(Object) { 817 DidInsert = 818 EI.ObjectsUnderConstruction 819 .insert({Object, HasBases ? ConstructionPhase::Bases 820 : ConstructionPhase::AfterBases}) 821 .second; 822 } 823 void finishedConstructingBases() { 824 EI.ObjectsUnderConstruction[Object] = ConstructionPhase::AfterBases; 825 } 826 void finishedConstructingFields() { 827 EI.ObjectsUnderConstruction[Object] = ConstructionPhase::AfterFields; 828 } 829 ~EvaluatingConstructorRAII() { 830 if (DidInsert) EI.ObjectsUnderConstruction.erase(Object); 831 } 832 }; 833 834 struct EvaluatingDestructorRAII { 835 EvalInfo &EI; 836 ObjectUnderConstruction Object; 837 bool DidInsert; 838 EvaluatingDestructorRAII(EvalInfo &EI, ObjectUnderConstruction Object) 839 : EI(EI), Object(Object) { 840 DidInsert = EI.ObjectsUnderConstruction 841 .insert({Object, ConstructionPhase::Destroying}) 842 .second; 843 } 844 void startedDestroyingBases() { 845 EI.ObjectsUnderConstruction[Object] = 846 ConstructionPhase::DestroyingBases; 847 } 848 ~EvaluatingDestructorRAII() { 849 if (DidInsert) 850 EI.ObjectsUnderConstruction.erase(Object); 851 } 852 }; 853 854 ConstructionPhase 855 isEvaluatingCtorDtor(APValue::LValueBase Base, 856 ArrayRef<APValue::LValuePathEntry> Path) { 857 return ObjectsUnderConstruction.lookup({Base, Path}); 858 } 859 860 /// If we're currently speculatively evaluating, the outermost call stack 861 /// depth at which we can mutate state, otherwise 0. 862 unsigned SpeculativeEvaluationDepth = 0; 863 864 /// The current array initialization index, if we're performing array 865 /// initialization. 866 uint64_t ArrayInitIndex = -1; 867 868 /// HasActiveDiagnostic - Was the previous diagnostic stored? If so, further 869 /// notes attached to it will also be stored, otherwise they will not be. 870 bool HasActiveDiagnostic; 871 872 /// Have we emitted a diagnostic explaining why we couldn't constant 873 /// fold (not just why it's not strictly a constant expression)? 874 bool HasFoldFailureDiagnostic; 875 876 /// Whether or not we're in a context where the front end requires a 877 /// constant value. 878 bool InConstantContext; 879 880 /// Whether we're checking that an expression is a potential constant 881 /// expression. If so, do not fail on constructs that could become constant 882 /// later on (such as a use of an undefined global). 883 bool CheckingPotentialConstantExpression = false; 884 885 /// Whether we're checking for an expression that has undefined behavior. 886 /// If so, we will produce warnings if we encounter an operation that is 887 /// always undefined. 888 bool CheckingForUndefinedBehavior = false; 889 890 enum EvaluationMode { 891 /// Evaluate as a constant expression. Stop if we find that the expression 892 /// is not a constant expression. 893 EM_ConstantExpression, 894 895 /// Evaluate as a constant expression. Stop if we find that the expression 896 /// is not a constant expression. Some expressions can be retried in the 897 /// optimizer if we don't constant fold them here, but in an unevaluated 898 /// context we try to fold them immediately since the optimizer never 899 /// gets a chance to look at it. 900 EM_ConstantExpressionUnevaluated, 901 902 /// Fold the expression to a constant. Stop if we hit a side-effect that 903 /// we can't model. 904 EM_ConstantFold, 905 906 /// Evaluate in any way we know how. Don't worry about side-effects that 907 /// can't be modeled. 908 EM_IgnoreSideEffects, 909 } EvalMode; 910 911 /// Are we checking whether the expression is a potential constant 912 /// expression? 913 bool checkingPotentialConstantExpression() const override { 914 return CheckingPotentialConstantExpression; 915 } 916 917 /// Are we checking an expression for overflow? 918 // FIXME: We should check for any kind of undefined or suspicious behavior 919 // in such constructs, not just overflow. 920 bool checkingForUndefinedBehavior() const override { 921 return CheckingForUndefinedBehavior; 922 } 923 924 EvalInfo(const ASTContext &C, Expr::EvalStatus &S, EvaluationMode Mode) 925 : Ctx(const_cast<ASTContext &>(C)), EvalStatus(S), CurrentCall(nullptr), 926 CallStackDepth(0), NextCallIndex(1), 927 StepsLeft(C.getLangOpts().ConstexprStepLimit), 928 EnableNewConstInterp(C.getLangOpts().EnableNewConstInterp), 929 BottomFrame(*this, SourceLocation(), nullptr, nullptr, nullptr), 930 EvaluatingDecl((const ValueDecl *)nullptr), 931 EvaluatingDeclValue(nullptr), HasActiveDiagnostic(false), 932 HasFoldFailureDiagnostic(false), InConstantContext(false), 933 EvalMode(Mode) {} 934 935 ~EvalInfo() { 936 discardCleanups(); 937 } 938 939 void setEvaluatingDecl(APValue::LValueBase Base, APValue &Value, 940 EvaluatingDeclKind EDK = EvaluatingDeclKind::Ctor) { 941 EvaluatingDecl = Base; 942 IsEvaluatingDecl = EDK; 943 EvaluatingDeclValue = &Value; 944 } 945 946 bool CheckCallLimit(SourceLocation Loc) { 947 // Don't perform any constexpr calls (other than the call we're checking) 948 // when checking a potential constant expression. 949 if (checkingPotentialConstantExpression() && CallStackDepth > 1) 950 return false; 951 if (NextCallIndex == 0) { 952 // NextCallIndex has wrapped around. 953 FFDiag(Loc, diag::note_constexpr_call_limit_exceeded); 954 return false; 955 } 956 if (CallStackDepth <= getLangOpts().ConstexprCallDepth) 957 return true; 958 FFDiag(Loc, diag::note_constexpr_depth_limit_exceeded) 959 << getLangOpts().ConstexprCallDepth; 960 return false; 961 } 962 963 std::pair<CallStackFrame *, unsigned> 964 getCallFrameAndDepth(unsigned CallIndex) { 965 assert(CallIndex && "no call index in getCallFrameAndDepth"); 966 // We will eventually hit BottomFrame, which has Index 1, so Frame can't 967 // be null in this loop. 968 unsigned Depth = CallStackDepth; 969 CallStackFrame *Frame = CurrentCall; 970 while (Frame->Index > CallIndex) { 971 Frame = Frame->Caller; 972 --Depth; 973 } 974 if (Frame->Index == CallIndex) 975 return {Frame, Depth}; 976 return {nullptr, 0}; 977 } 978 979 bool nextStep(const Stmt *S) { 980 if (!StepsLeft) { 981 FFDiag(S->getBeginLoc(), diag::note_constexpr_step_limit_exceeded); 982 return false; 983 } 984 --StepsLeft; 985 return true; 986 } 987 988 APValue *createHeapAlloc(const Expr *E, QualType T, LValue &LV); 989 990 Optional<DynAlloc*> lookupDynamicAlloc(DynamicAllocLValue DA) { 991 Optional<DynAlloc*> Result; 992 auto It = HeapAllocs.find(DA); 993 if (It != HeapAllocs.end()) 994 Result = &It->second; 995 return Result; 996 } 997 998 /// Information about a stack frame for std::allocator<T>::[de]allocate. 999 struct StdAllocatorCaller { 1000 unsigned FrameIndex; 1001 QualType ElemType; 1002 explicit operator bool() const { return FrameIndex != 0; }; 1003 }; 1004 1005 StdAllocatorCaller getStdAllocatorCaller(StringRef FnName) const { 1006 for (const CallStackFrame *Call = CurrentCall; Call != &BottomFrame; 1007 Call = Call->Caller) { 1008 const auto *MD = dyn_cast_or_null<CXXMethodDecl>(Call->Callee); 1009 if (!MD) 1010 continue; 1011 const IdentifierInfo *FnII = MD->getIdentifier(); 1012 if (!FnII || !FnII->isStr(FnName)) 1013 continue; 1014 1015 const auto *CTSD = 1016 dyn_cast<ClassTemplateSpecializationDecl>(MD->getParent()); 1017 if (!CTSD) 1018 continue; 1019 1020 const IdentifierInfo *ClassII = CTSD->getIdentifier(); 1021 const TemplateArgumentList &TAL = CTSD->getTemplateArgs(); 1022 if (CTSD->isInStdNamespace() && ClassII && 1023 ClassII->isStr("allocator") && TAL.size() >= 1 && 1024 TAL[0].getKind() == TemplateArgument::Type) 1025 return {Call->Index, TAL[0].getAsType()}; 1026 } 1027 1028 return {}; 1029 } 1030 1031 void performLifetimeExtension() { 1032 // Disable the cleanups for lifetime-extended temporaries. 1033 CleanupStack.erase( 1034 std::remove_if(CleanupStack.begin(), CleanupStack.end(), 1035 [](Cleanup &C) { return C.isLifetimeExtended(); }), 1036 CleanupStack.end()); 1037 } 1038 1039 /// Throw away any remaining cleanups at the end of evaluation. If any 1040 /// cleanups would have had a side-effect, note that as an unmodeled 1041 /// side-effect and return false. Otherwise, return true. 1042 bool discardCleanups() { 1043 for (Cleanup &C : CleanupStack) { 1044 if (C.hasSideEffect() && !noteSideEffect()) { 1045 CleanupStack.clear(); 1046 return false; 1047 } 1048 } 1049 CleanupStack.clear(); 1050 return true; 1051 } 1052 1053 private: 1054 interp::Frame *getCurrentFrame() override { return CurrentCall; } 1055 const interp::Frame *getBottomFrame() const override { return &BottomFrame; } 1056 1057 bool hasActiveDiagnostic() override { return HasActiveDiagnostic; } 1058 void setActiveDiagnostic(bool Flag) override { HasActiveDiagnostic = Flag; } 1059 1060 void setFoldFailureDiagnostic(bool Flag) override { 1061 HasFoldFailureDiagnostic = Flag; 1062 } 1063 1064 Expr::EvalStatus &getEvalStatus() const override { return EvalStatus; } 1065 1066 ASTContext &getCtx() const override { return Ctx; } 1067 1068 // If we have a prior diagnostic, it will be noting that the expression 1069 // isn't a constant expression. This diagnostic is more important, 1070 // unless we require this evaluation to produce a constant expression. 1071 // 1072 // FIXME: We might want to show both diagnostics to the user in 1073 // EM_ConstantFold mode. 1074 bool hasPriorDiagnostic() override { 1075 if (!EvalStatus.Diag->empty()) { 1076 switch (EvalMode) { 1077 case EM_ConstantFold: 1078 case EM_IgnoreSideEffects: 1079 if (!HasFoldFailureDiagnostic) 1080 break; 1081 // We've already failed to fold something. Keep that diagnostic. 1082 LLVM_FALLTHROUGH; 1083 case EM_ConstantExpression: 1084 case EM_ConstantExpressionUnevaluated: 1085 setActiveDiagnostic(false); 1086 return true; 1087 } 1088 } 1089 return false; 1090 } 1091 1092 unsigned getCallStackDepth() override { return CallStackDepth; } 1093 1094 public: 1095 /// Should we continue evaluation after encountering a side-effect that we 1096 /// couldn't model? 1097 bool keepEvaluatingAfterSideEffect() { 1098 switch (EvalMode) { 1099 case EM_IgnoreSideEffects: 1100 return true; 1101 1102 case EM_ConstantExpression: 1103 case EM_ConstantExpressionUnevaluated: 1104 case EM_ConstantFold: 1105 // By default, assume any side effect might be valid in some other 1106 // evaluation of this expression from a different context. 1107 return checkingPotentialConstantExpression() || 1108 checkingForUndefinedBehavior(); 1109 } 1110 llvm_unreachable("Missed EvalMode case"); 1111 } 1112 1113 /// Note that we have had a side-effect, and determine whether we should 1114 /// keep evaluating. 1115 bool noteSideEffect() { 1116 EvalStatus.HasSideEffects = true; 1117 return keepEvaluatingAfterSideEffect(); 1118 } 1119 1120 /// Should we continue evaluation after encountering undefined behavior? 1121 bool keepEvaluatingAfterUndefinedBehavior() { 1122 switch (EvalMode) { 1123 case EM_IgnoreSideEffects: 1124 case EM_ConstantFold: 1125 return true; 1126 1127 case EM_ConstantExpression: 1128 case EM_ConstantExpressionUnevaluated: 1129 return checkingForUndefinedBehavior(); 1130 } 1131 llvm_unreachable("Missed EvalMode case"); 1132 } 1133 1134 /// Note that we hit something that was technically undefined behavior, but 1135 /// that we can evaluate past it (such as signed overflow or floating-point 1136 /// division by zero.) 1137 bool noteUndefinedBehavior() override { 1138 EvalStatus.HasUndefinedBehavior = true; 1139 return keepEvaluatingAfterUndefinedBehavior(); 1140 } 1141 1142 /// Should we continue evaluation as much as possible after encountering a 1143 /// construct which can't be reduced to a value? 1144 bool keepEvaluatingAfterFailure() const override { 1145 if (!StepsLeft) 1146 return false; 1147 1148 switch (EvalMode) { 1149 case EM_ConstantExpression: 1150 case EM_ConstantExpressionUnevaluated: 1151 case EM_ConstantFold: 1152 case EM_IgnoreSideEffects: 1153 return checkingPotentialConstantExpression() || 1154 checkingForUndefinedBehavior(); 1155 } 1156 llvm_unreachable("Missed EvalMode case"); 1157 } 1158 1159 /// Notes that we failed to evaluate an expression that other expressions 1160 /// directly depend on, and determine if we should keep evaluating. This 1161 /// should only be called if we actually intend to keep evaluating. 1162 /// 1163 /// Call noteSideEffect() instead if we may be able to ignore the value that 1164 /// we failed to evaluate, e.g. if we failed to evaluate Foo() in: 1165 /// 1166 /// (Foo(), 1) // use noteSideEffect 1167 /// (Foo() || true) // use noteSideEffect 1168 /// Foo() + 1 // use noteFailure 1169 LLVM_NODISCARD bool noteFailure() { 1170 // Failure when evaluating some expression often means there is some 1171 // subexpression whose evaluation was skipped. Therefore, (because we 1172 // don't track whether we skipped an expression when unwinding after an 1173 // evaluation failure) every evaluation failure that bubbles up from a 1174 // subexpression implies that a side-effect has potentially happened. We 1175 // skip setting the HasSideEffects flag to true until we decide to 1176 // continue evaluating after that point, which happens here. 1177 bool KeepGoing = keepEvaluatingAfterFailure(); 1178 EvalStatus.HasSideEffects |= KeepGoing; 1179 return KeepGoing; 1180 } 1181 1182 class ArrayInitLoopIndex { 1183 EvalInfo &Info; 1184 uint64_t OuterIndex; 1185 1186 public: 1187 ArrayInitLoopIndex(EvalInfo &Info) 1188 : Info(Info), OuterIndex(Info.ArrayInitIndex) { 1189 Info.ArrayInitIndex = 0; 1190 } 1191 ~ArrayInitLoopIndex() { Info.ArrayInitIndex = OuterIndex; } 1192 1193 operator uint64_t&() { return Info.ArrayInitIndex; } 1194 }; 1195 }; 1196 1197 /// Object used to treat all foldable expressions as constant expressions. 1198 struct FoldConstant { 1199 EvalInfo &Info; 1200 bool Enabled; 1201 bool HadNoPriorDiags; 1202 EvalInfo::EvaluationMode OldMode; 1203 1204 explicit FoldConstant(EvalInfo &Info, bool Enabled) 1205 : Info(Info), 1206 Enabled(Enabled), 1207 HadNoPriorDiags(Info.EvalStatus.Diag && 1208 Info.EvalStatus.Diag->empty() && 1209 !Info.EvalStatus.HasSideEffects), 1210 OldMode(Info.EvalMode) { 1211 if (Enabled) 1212 Info.EvalMode = EvalInfo::EM_ConstantFold; 1213 } 1214 void keepDiagnostics() { Enabled = false; } 1215 ~FoldConstant() { 1216 if (Enabled && HadNoPriorDiags && !Info.EvalStatus.Diag->empty() && 1217 !Info.EvalStatus.HasSideEffects) 1218 Info.EvalStatus.Diag->clear(); 1219 Info.EvalMode = OldMode; 1220 } 1221 }; 1222 1223 /// RAII object used to set the current evaluation mode to ignore 1224 /// side-effects. 1225 struct IgnoreSideEffectsRAII { 1226 EvalInfo &Info; 1227 EvalInfo::EvaluationMode OldMode; 1228 explicit IgnoreSideEffectsRAII(EvalInfo &Info) 1229 : Info(Info), OldMode(Info.EvalMode) { 1230 Info.EvalMode = EvalInfo::EM_IgnoreSideEffects; 1231 } 1232 1233 ~IgnoreSideEffectsRAII() { Info.EvalMode = OldMode; } 1234 }; 1235 1236 /// RAII object used to optionally suppress diagnostics and side-effects from 1237 /// a speculative evaluation. 1238 class SpeculativeEvaluationRAII { 1239 EvalInfo *Info = nullptr; 1240 Expr::EvalStatus OldStatus; 1241 unsigned OldSpeculativeEvaluationDepth; 1242 1243 void moveFromAndCancel(SpeculativeEvaluationRAII &&Other) { 1244 Info = Other.Info; 1245 OldStatus = Other.OldStatus; 1246 OldSpeculativeEvaluationDepth = Other.OldSpeculativeEvaluationDepth; 1247 Other.Info = nullptr; 1248 } 1249 1250 void maybeRestoreState() { 1251 if (!Info) 1252 return; 1253 1254 Info->EvalStatus = OldStatus; 1255 Info->SpeculativeEvaluationDepth = OldSpeculativeEvaluationDepth; 1256 } 1257 1258 public: 1259 SpeculativeEvaluationRAII() = default; 1260 1261 SpeculativeEvaluationRAII( 1262 EvalInfo &Info, SmallVectorImpl<PartialDiagnosticAt> *NewDiag = nullptr) 1263 : Info(&Info), OldStatus(Info.EvalStatus), 1264 OldSpeculativeEvaluationDepth(Info.SpeculativeEvaluationDepth) { 1265 Info.EvalStatus.Diag = NewDiag; 1266 Info.SpeculativeEvaluationDepth = Info.CallStackDepth + 1; 1267 } 1268 1269 SpeculativeEvaluationRAII(const SpeculativeEvaluationRAII &Other) = delete; 1270 SpeculativeEvaluationRAII(SpeculativeEvaluationRAII &&Other) { 1271 moveFromAndCancel(std::move(Other)); 1272 } 1273 1274 SpeculativeEvaluationRAII &operator=(SpeculativeEvaluationRAII &&Other) { 1275 maybeRestoreState(); 1276 moveFromAndCancel(std::move(Other)); 1277 return *this; 1278 } 1279 1280 ~SpeculativeEvaluationRAII() { maybeRestoreState(); } 1281 }; 1282 1283 /// RAII object wrapping a full-expression or block scope, and handling 1284 /// the ending of the lifetime of temporaries created within it. 1285 template<bool IsFullExpression> 1286 class ScopeRAII { 1287 EvalInfo &Info; 1288 unsigned OldStackSize; 1289 public: 1290 ScopeRAII(EvalInfo &Info) 1291 : Info(Info), OldStackSize(Info.CleanupStack.size()) { 1292 // Push a new temporary version. This is needed to distinguish between 1293 // temporaries created in different iterations of a loop. 1294 Info.CurrentCall->pushTempVersion(); 1295 } 1296 bool destroy(bool RunDestructors = true) { 1297 bool OK = cleanup(Info, RunDestructors, OldStackSize); 1298 OldStackSize = -1U; 1299 return OK; 1300 } 1301 ~ScopeRAII() { 1302 if (OldStackSize != -1U) 1303 destroy(false); 1304 // Body moved to a static method to encourage the compiler to inline away 1305 // instances of this class. 1306 Info.CurrentCall->popTempVersion(); 1307 } 1308 private: 1309 static bool cleanup(EvalInfo &Info, bool RunDestructors, 1310 unsigned OldStackSize) { 1311 assert(OldStackSize <= Info.CleanupStack.size() && 1312 "running cleanups out of order?"); 1313 1314 // Run all cleanups for a block scope, and non-lifetime-extended cleanups 1315 // for a full-expression scope. 1316 bool Success = true; 1317 for (unsigned I = Info.CleanupStack.size(); I > OldStackSize; --I) { 1318 if (!(IsFullExpression && 1319 Info.CleanupStack[I - 1].isLifetimeExtended())) { 1320 if (!Info.CleanupStack[I - 1].endLifetime(Info, RunDestructors)) { 1321 Success = false; 1322 break; 1323 } 1324 } 1325 } 1326 1327 // Compact lifetime-extended cleanups. 1328 auto NewEnd = Info.CleanupStack.begin() + OldStackSize; 1329 if (IsFullExpression) 1330 NewEnd = 1331 std::remove_if(NewEnd, Info.CleanupStack.end(), 1332 [](Cleanup &C) { return !C.isLifetimeExtended(); }); 1333 Info.CleanupStack.erase(NewEnd, Info.CleanupStack.end()); 1334 return Success; 1335 } 1336 }; 1337 typedef ScopeRAII<false> BlockScopeRAII; 1338 typedef ScopeRAII<true> FullExpressionRAII; 1339 } 1340 1341 bool SubobjectDesignator::checkSubobject(EvalInfo &Info, const Expr *E, 1342 CheckSubobjectKind CSK) { 1343 if (Invalid) 1344 return false; 1345 if (isOnePastTheEnd()) { 1346 Info.CCEDiag(E, diag::note_constexpr_past_end_subobject) 1347 << CSK; 1348 setInvalid(); 1349 return false; 1350 } 1351 // Note, we do not diagnose if isMostDerivedAnUnsizedArray(), because there 1352 // must actually be at least one array element; even a VLA cannot have a 1353 // bound of zero. And if our index is nonzero, we already had a CCEDiag. 1354 return true; 1355 } 1356 1357 void SubobjectDesignator::diagnoseUnsizedArrayPointerArithmetic(EvalInfo &Info, 1358 const Expr *E) { 1359 Info.CCEDiag(E, diag::note_constexpr_unsized_array_indexed); 1360 // Do not set the designator as invalid: we can represent this situation, 1361 // and correct handling of __builtin_object_size requires us to do so. 1362 } 1363 1364 void SubobjectDesignator::diagnosePointerArithmetic(EvalInfo &Info, 1365 const Expr *E, 1366 const APSInt &N) { 1367 // If we're complaining, we must be able to statically determine the size of 1368 // the most derived array. 1369 if (MostDerivedPathLength == Entries.size() && MostDerivedIsArrayElement) 1370 Info.CCEDiag(E, diag::note_constexpr_array_index) 1371 << N << /*array*/ 0 1372 << static_cast<unsigned>(getMostDerivedArraySize()); 1373 else 1374 Info.CCEDiag(E, diag::note_constexpr_array_index) 1375 << N << /*non-array*/ 1; 1376 setInvalid(); 1377 } 1378 1379 CallStackFrame::CallStackFrame(EvalInfo &Info, SourceLocation CallLoc, 1380 const FunctionDecl *Callee, const LValue *This, 1381 APValue *Arguments) 1382 : Info(Info), Caller(Info.CurrentCall), Callee(Callee), This(This), 1383 Arguments(Arguments), CallLoc(CallLoc), Index(Info.NextCallIndex++) { 1384 Info.CurrentCall = this; 1385 ++Info.CallStackDepth; 1386 } 1387 1388 CallStackFrame::~CallStackFrame() { 1389 assert(Info.CurrentCall == this && "calls retired out of order"); 1390 --Info.CallStackDepth; 1391 Info.CurrentCall = Caller; 1392 } 1393 1394 static bool isRead(AccessKinds AK) { 1395 return AK == AK_Read || AK == AK_ReadObjectRepresentation; 1396 } 1397 1398 static bool isModification(AccessKinds AK) { 1399 switch (AK) { 1400 case AK_Read: 1401 case AK_ReadObjectRepresentation: 1402 case AK_MemberCall: 1403 case AK_DynamicCast: 1404 case AK_TypeId: 1405 return false; 1406 case AK_Assign: 1407 case AK_Increment: 1408 case AK_Decrement: 1409 case AK_Construct: 1410 case AK_Destroy: 1411 return true; 1412 } 1413 llvm_unreachable("unknown access kind"); 1414 } 1415 1416 static bool isAnyAccess(AccessKinds AK) { 1417 return isRead(AK) || isModification(AK); 1418 } 1419 1420 /// Is this an access per the C++ definition? 1421 static bool isFormalAccess(AccessKinds AK) { 1422 return isAnyAccess(AK) && AK != AK_Construct && AK != AK_Destroy; 1423 } 1424 1425 /// Is this kind of axcess valid on an indeterminate object value? 1426 static bool isValidIndeterminateAccess(AccessKinds AK) { 1427 switch (AK) { 1428 case AK_Read: 1429 case AK_Increment: 1430 case AK_Decrement: 1431 // These need the object's value. 1432 return false; 1433 1434 case AK_ReadObjectRepresentation: 1435 case AK_Assign: 1436 case AK_Construct: 1437 case AK_Destroy: 1438 // Construction and destruction don't need the value. 1439 return true; 1440 1441 case AK_MemberCall: 1442 case AK_DynamicCast: 1443 case AK_TypeId: 1444 // These aren't really meaningful on scalars. 1445 return true; 1446 } 1447 llvm_unreachable("unknown access kind"); 1448 } 1449 1450 namespace { 1451 struct ComplexValue { 1452 private: 1453 bool IsInt; 1454 1455 public: 1456 APSInt IntReal, IntImag; 1457 APFloat FloatReal, FloatImag; 1458 1459 ComplexValue() : FloatReal(APFloat::Bogus()), FloatImag(APFloat::Bogus()) {} 1460 1461 void makeComplexFloat() { IsInt = false; } 1462 bool isComplexFloat() const { return !IsInt; } 1463 APFloat &getComplexFloatReal() { return FloatReal; } 1464 APFloat &getComplexFloatImag() { return FloatImag; } 1465 1466 void makeComplexInt() { IsInt = true; } 1467 bool isComplexInt() const { return IsInt; } 1468 APSInt &getComplexIntReal() { return IntReal; } 1469 APSInt &getComplexIntImag() { return IntImag; } 1470 1471 void moveInto(APValue &v) const { 1472 if (isComplexFloat()) 1473 v = APValue(FloatReal, FloatImag); 1474 else 1475 v = APValue(IntReal, IntImag); 1476 } 1477 void setFrom(const APValue &v) { 1478 assert(v.isComplexFloat() || v.isComplexInt()); 1479 if (v.isComplexFloat()) { 1480 makeComplexFloat(); 1481 FloatReal = v.getComplexFloatReal(); 1482 FloatImag = v.getComplexFloatImag(); 1483 } else { 1484 makeComplexInt(); 1485 IntReal = v.getComplexIntReal(); 1486 IntImag = v.getComplexIntImag(); 1487 } 1488 } 1489 }; 1490 1491 struct LValue { 1492 APValue::LValueBase Base; 1493 CharUnits Offset; 1494 SubobjectDesignator Designator; 1495 bool IsNullPtr : 1; 1496 bool InvalidBase : 1; 1497 1498 const APValue::LValueBase getLValueBase() const { return Base; } 1499 CharUnits &getLValueOffset() { return Offset; } 1500 const CharUnits &getLValueOffset() const { return Offset; } 1501 SubobjectDesignator &getLValueDesignator() { return Designator; } 1502 const SubobjectDesignator &getLValueDesignator() const { return Designator;} 1503 bool isNullPointer() const { return IsNullPtr;} 1504 1505 unsigned getLValueCallIndex() const { return Base.getCallIndex(); } 1506 unsigned getLValueVersion() const { return Base.getVersion(); } 1507 1508 void moveInto(APValue &V) const { 1509 if (Designator.Invalid) 1510 V = APValue(Base, Offset, APValue::NoLValuePath(), IsNullPtr); 1511 else { 1512 assert(!InvalidBase && "APValues can't handle invalid LValue bases"); 1513 V = APValue(Base, Offset, Designator.Entries, 1514 Designator.IsOnePastTheEnd, IsNullPtr); 1515 } 1516 } 1517 void setFrom(ASTContext &Ctx, const APValue &V) { 1518 assert(V.isLValue() && "Setting LValue from a non-LValue?"); 1519 Base = V.getLValueBase(); 1520 Offset = V.getLValueOffset(); 1521 InvalidBase = false; 1522 Designator = SubobjectDesignator(Ctx, V); 1523 IsNullPtr = V.isNullPointer(); 1524 } 1525 1526 void set(APValue::LValueBase B, bool BInvalid = false) { 1527 #ifndef NDEBUG 1528 // We only allow a few types of invalid bases. Enforce that here. 1529 if (BInvalid) { 1530 const auto *E = B.get<const Expr *>(); 1531 assert((isa<MemberExpr>(E) || tryUnwrapAllocSizeCall(E)) && 1532 "Unexpected type of invalid base"); 1533 } 1534 #endif 1535 1536 Base = B; 1537 Offset = CharUnits::fromQuantity(0); 1538 InvalidBase = BInvalid; 1539 Designator = SubobjectDesignator(getType(B)); 1540 IsNullPtr = false; 1541 } 1542 1543 void setNull(ASTContext &Ctx, QualType PointerTy) { 1544 Base = (Expr *)nullptr; 1545 Offset = 1546 CharUnits::fromQuantity(Ctx.getTargetNullPointerValue(PointerTy)); 1547 InvalidBase = false; 1548 Designator = SubobjectDesignator(PointerTy->getPointeeType()); 1549 IsNullPtr = true; 1550 } 1551 1552 void setInvalid(APValue::LValueBase B, unsigned I = 0) { 1553 set(B, true); 1554 } 1555 1556 std::string toString(ASTContext &Ctx, QualType T) const { 1557 APValue Printable; 1558 moveInto(Printable); 1559 return Printable.getAsString(Ctx, T); 1560 } 1561 1562 private: 1563 // Check that this LValue is not based on a null pointer. If it is, produce 1564 // a diagnostic and mark the designator as invalid. 1565 template <typename GenDiagType> 1566 bool checkNullPointerDiagnosingWith(const GenDiagType &GenDiag) { 1567 if (Designator.Invalid) 1568 return false; 1569 if (IsNullPtr) { 1570 GenDiag(); 1571 Designator.setInvalid(); 1572 return false; 1573 } 1574 return true; 1575 } 1576 1577 public: 1578 bool checkNullPointer(EvalInfo &Info, const Expr *E, 1579 CheckSubobjectKind CSK) { 1580 return checkNullPointerDiagnosingWith([&Info, E, CSK] { 1581 Info.CCEDiag(E, diag::note_constexpr_null_subobject) << CSK; 1582 }); 1583 } 1584 1585 bool checkNullPointerForFoldAccess(EvalInfo &Info, const Expr *E, 1586 AccessKinds AK) { 1587 return checkNullPointerDiagnosingWith([&Info, E, AK] { 1588 Info.FFDiag(E, diag::note_constexpr_access_null) << AK; 1589 }); 1590 } 1591 1592 // Check this LValue refers to an object. If not, set the designator to be 1593 // invalid and emit a diagnostic. 1594 bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK) { 1595 return (CSK == CSK_ArrayToPointer || checkNullPointer(Info, E, CSK)) && 1596 Designator.checkSubobject(Info, E, CSK); 1597 } 1598 1599 void addDecl(EvalInfo &Info, const Expr *E, 1600 const Decl *D, bool Virtual = false) { 1601 if (checkSubobject(Info, E, isa<FieldDecl>(D) ? CSK_Field : CSK_Base)) 1602 Designator.addDeclUnchecked(D, Virtual); 1603 } 1604 void addUnsizedArray(EvalInfo &Info, const Expr *E, QualType ElemTy) { 1605 if (!Designator.Entries.empty()) { 1606 Info.CCEDiag(E, diag::note_constexpr_unsupported_unsized_array); 1607 Designator.setInvalid(); 1608 return; 1609 } 1610 if (checkSubobject(Info, E, CSK_ArrayToPointer)) { 1611 assert(getType(Base)->isPointerType() || getType(Base)->isArrayType()); 1612 Designator.FirstEntryIsAnUnsizedArray = true; 1613 Designator.addUnsizedArrayUnchecked(ElemTy); 1614 } 1615 } 1616 void addArray(EvalInfo &Info, const Expr *E, const ConstantArrayType *CAT) { 1617 if (checkSubobject(Info, E, CSK_ArrayToPointer)) 1618 Designator.addArrayUnchecked(CAT); 1619 } 1620 void addComplex(EvalInfo &Info, const Expr *E, QualType EltTy, bool Imag) { 1621 if (checkSubobject(Info, E, Imag ? CSK_Imag : CSK_Real)) 1622 Designator.addComplexUnchecked(EltTy, Imag); 1623 } 1624 void clearIsNullPointer() { 1625 IsNullPtr = false; 1626 } 1627 void adjustOffsetAndIndex(EvalInfo &Info, const Expr *E, 1628 const APSInt &Index, CharUnits ElementSize) { 1629 // An index of 0 has no effect. (In C, adding 0 to a null pointer is UB, 1630 // but we're not required to diagnose it and it's valid in C++.) 1631 if (!Index) 1632 return; 1633 1634 // Compute the new offset in the appropriate width, wrapping at 64 bits. 1635 // FIXME: When compiling for a 32-bit target, we should use 32-bit 1636 // offsets. 1637 uint64_t Offset64 = Offset.getQuantity(); 1638 uint64_t ElemSize64 = ElementSize.getQuantity(); 1639 uint64_t Index64 = Index.extOrTrunc(64).getZExtValue(); 1640 Offset = CharUnits::fromQuantity(Offset64 + ElemSize64 * Index64); 1641 1642 if (checkNullPointer(Info, E, CSK_ArrayIndex)) 1643 Designator.adjustIndex(Info, E, Index); 1644 clearIsNullPointer(); 1645 } 1646 void adjustOffset(CharUnits N) { 1647 Offset += N; 1648 if (N.getQuantity()) 1649 clearIsNullPointer(); 1650 } 1651 }; 1652 1653 struct MemberPtr { 1654 MemberPtr() {} 1655 explicit MemberPtr(const ValueDecl *Decl) : 1656 DeclAndIsDerivedMember(Decl, false), Path() {} 1657 1658 /// The member or (direct or indirect) field referred to by this member 1659 /// pointer, or 0 if this is a null member pointer. 1660 const ValueDecl *getDecl() const { 1661 return DeclAndIsDerivedMember.getPointer(); 1662 } 1663 /// Is this actually a member of some type derived from the relevant class? 1664 bool isDerivedMember() const { 1665 return DeclAndIsDerivedMember.getInt(); 1666 } 1667 /// Get the class which the declaration actually lives in. 1668 const CXXRecordDecl *getContainingRecord() const { 1669 return cast<CXXRecordDecl>( 1670 DeclAndIsDerivedMember.getPointer()->getDeclContext()); 1671 } 1672 1673 void moveInto(APValue &V) const { 1674 V = APValue(getDecl(), isDerivedMember(), Path); 1675 } 1676 void setFrom(const APValue &V) { 1677 assert(V.isMemberPointer()); 1678 DeclAndIsDerivedMember.setPointer(V.getMemberPointerDecl()); 1679 DeclAndIsDerivedMember.setInt(V.isMemberPointerToDerivedMember()); 1680 Path.clear(); 1681 ArrayRef<const CXXRecordDecl*> P = V.getMemberPointerPath(); 1682 Path.insert(Path.end(), P.begin(), P.end()); 1683 } 1684 1685 /// DeclAndIsDerivedMember - The member declaration, and a flag indicating 1686 /// whether the member is a member of some class derived from the class type 1687 /// of the member pointer. 1688 llvm::PointerIntPair<const ValueDecl*, 1, bool> DeclAndIsDerivedMember; 1689 /// Path - The path of base/derived classes from the member declaration's 1690 /// class (exclusive) to the class type of the member pointer (inclusive). 1691 SmallVector<const CXXRecordDecl*, 4> Path; 1692 1693 /// Perform a cast towards the class of the Decl (either up or down the 1694 /// hierarchy). 1695 bool castBack(const CXXRecordDecl *Class) { 1696 assert(!Path.empty()); 1697 const CXXRecordDecl *Expected; 1698 if (Path.size() >= 2) 1699 Expected = Path[Path.size() - 2]; 1700 else 1701 Expected = getContainingRecord(); 1702 if (Expected->getCanonicalDecl() != Class->getCanonicalDecl()) { 1703 // C++11 [expr.static.cast]p12: In a conversion from (D::*) to (B::*), 1704 // if B does not contain the original member and is not a base or 1705 // derived class of the class containing the original member, the result 1706 // of the cast is undefined. 1707 // C++11 [conv.mem]p2 does not cover this case for a cast from (B::*) to 1708 // (D::*). We consider that to be a language defect. 1709 return false; 1710 } 1711 Path.pop_back(); 1712 return true; 1713 } 1714 /// Perform a base-to-derived member pointer cast. 1715 bool castToDerived(const CXXRecordDecl *Derived) { 1716 if (!getDecl()) 1717 return true; 1718 if (!isDerivedMember()) { 1719 Path.push_back(Derived); 1720 return true; 1721 } 1722 if (!castBack(Derived)) 1723 return false; 1724 if (Path.empty()) 1725 DeclAndIsDerivedMember.setInt(false); 1726 return true; 1727 } 1728 /// Perform a derived-to-base member pointer cast. 1729 bool castToBase(const CXXRecordDecl *Base) { 1730 if (!getDecl()) 1731 return true; 1732 if (Path.empty()) 1733 DeclAndIsDerivedMember.setInt(true); 1734 if (isDerivedMember()) { 1735 Path.push_back(Base); 1736 return true; 1737 } 1738 return castBack(Base); 1739 } 1740 }; 1741 1742 /// Compare two member pointers, which are assumed to be of the same type. 1743 static bool operator==(const MemberPtr &LHS, const MemberPtr &RHS) { 1744 if (!LHS.getDecl() || !RHS.getDecl()) 1745 return !LHS.getDecl() && !RHS.getDecl(); 1746 if (LHS.getDecl()->getCanonicalDecl() != RHS.getDecl()->getCanonicalDecl()) 1747 return false; 1748 return LHS.Path == RHS.Path; 1749 } 1750 } 1751 1752 static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E); 1753 static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, 1754 const LValue &This, const Expr *E, 1755 bool AllowNonLiteralTypes = false); 1756 static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info, 1757 bool InvalidBaseOK = false); 1758 static bool EvaluatePointer(const Expr *E, LValue &Result, EvalInfo &Info, 1759 bool InvalidBaseOK = false); 1760 static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result, 1761 EvalInfo &Info); 1762 static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info); 1763 static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info); 1764 static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result, 1765 EvalInfo &Info); 1766 static bool EvaluateFloat(const Expr *E, APFloat &Result, EvalInfo &Info); 1767 static bool EvaluateComplex(const Expr *E, ComplexValue &Res, EvalInfo &Info); 1768 static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result, 1769 EvalInfo &Info); 1770 static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result); 1771 1772 /// Evaluate an integer or fixed point expression into an APResult. 1773 static bool EvaluateFixedPointOrInteger(const Expr *E, APFixedPoint &Result, 1774 EvalInfo &Info); 1775 1776 /// Evaluate only a fixed point expression into an APResult. 1777 static bool EvaluateFixedPoint(const Expr *E, APFixedPoint &Result, 1778 EvalInfo &Info); 1779 1780 //===----------------------------------------------------------------------===// 1781 // Misc utilities 1782 //===----------------------------------------------------------------------===// 1783 1784 /// Negate an APSInt in place, converting it to a signed form if necessary, and 1785 /// preserving its value (by extending by up to one bit as needed). 1786 static void negateAsSigned(APSInt &Int) { 1787 if (Int.isUnsigned() || Int.isMinSignedValue()) { 1788 Int = Int.extend(Int.getBitWidth() + 1); 1789 Int.setIsSigned(true); 1790 } 1791 Int = -Int; 1792 } 1793 1794 template<typename KeyT> 1795 APValue &CallStackFrame::createTemporary(const KeyT *Key, QualType T, 1796 bool IsLifetimeExtended, LValue &LV) { 1797 unsigned Version = getTempVersion(); 1798 APValue::LValueBase Base(Key, Index, Version); 1799 LV.set(Base); 1800 APValue &Result = Temporaries[MapKeyTy(Key, Version)]; 1801 assert(Result.isAbsent() && "temporary created multiple times"); 1802 1803 // If we're creating a temporary immediately in the operand of a speculative 1804 // evaluation, don't register a cleanup to be run outside the speculative 1805 // evaluation context, since we won't actually be able to initialize this 1806 // object. 1807 if (Index <= Info.SpeculativeEvaluationDepth) { 1808 if (T.isDestructedType()) 1809 Info.noteSideEffect(); 1810 } else { 1811 Info.CleanupStack.push_back(Cleanup(&Result, Base, T, IsLifetimeExtended)); 1812 } 1813 return Result; 1814 } 1815 1816 APValue *EvalInfo::createHeapAlloc(const Expr *E, QualType T, LValue &LV) { 1817 if (NumHeapAllocs > DynamicAllocLValue::getMaxIndex()) { 1818 FFDiag(E, diag::note_constexpr_heap_alloc_limit_exceeded); 1819 return nullptr; 1820 } 1821 1822 DynamicAllocLValue DA(NumHeapAllocs++); 1823 LV.set(APValue::LValueBase::getDynamicAlloc(DA, T)); 1824 auto Result = HeapAllocs.emplace(std::piecewise_construct, 1825 std::forward_as_tuple(DA), std::tuple<>()); 1826 assert(Result.second && "reused a heap alloc index?"); 1827 Result.first->second.AllocExpr = E; 1828 return &Result.first->second.Value; 1829 } 1830 1831 /// Produce a string describing the given constexpr call. 1832 void CallStackFrame::describe(raw_ostream &Out) { 1833 unsigned ArgIndex = 0; 1834 bool IsMemberCall = isa<CXXMethodDecl>(Callee) && 1835 !isa<CXXConstructorDecl>(Callee) && 1836 cast<CXXMethodDecl>(Callee)->isInstance(); 1837 1838 if (!IsMemberCall) 1839 Out << *Callee << '('; 1840 1841 if (This && IsMemberCall) { 1842 APValue Val; 1843 This->moveInto(Val); 1844 Val.printPretty(Out, Info.Ctx, 1845 This->Designator.MostDerivedType); 1846 // FIXME: Add parens around Val if needed. 1847 Out << "->" << *Callee << '('; 1848 IsMemberCall = false; 1849 } 1850 1851 for (FunctionDecl::param_const_iterator I = Callee->param_begin(), 1852 E = Callee->param_end(); I != E; ++I, ++ArgIndex) { 1853 if (ArgIndex > (unsigned)IsMemberCall) 1854 Out << ", "; 1855 1856 const ParmVarDecl *Param = *I; 1857 const APValue &Arg = Arguments[ArgIndex]; 1858 Arg.printPretty(Out, Info.Ctx, Param->getType()); 1859 1860 if (ArgIndex == 0 && IsMemberCall) 1861 Out << "->" << *Callee << '('; 1862 } 1863 1864 Out << ')'; 1865 } 1866 1867 /// Evaluate an expression to see if it had side-effects, and discard its 1868 /// result. 1869 /// \return \c true if the caller should keep evaluating. 1870 static bool EvaluateIgnoredValue(EvalInfo &Info, const Expr *E) { 1871 APValue Scratch; 1872 if (!Evaluate(Scratch, Info, E)) 1873 // We don't need the value, but we might have skipped a side effect here. 1874 return Info.noteSideEffect(); 1875 return true; 1876 } 1877 1878 /// Should this call expression be treated as a string literal? 1879 static bool IsStringLiteralCall(const CallExpr *E) { 1880 unsigned Builtin = E->getBuiltinCallee(); 1881 return (Builtin == Builtin::BI__builtin___CFStringMakeConstantString || 1882 Builtin == Builtin::BI__builtin___NSStringMakeConstantString); 1883 } 1884 1885 static bool IsGlobalLValue(APValue::LValueBase B) { 1886 // C++11 [expr.const]p3 An address constant expression is a prvalue core 1887 // constant expression of pointer type that evaluates to... 1888 1889 // ... a null pointer value, or a prvalue core constant expression of type 1890 // std::nullptr_t. 1891 if (!B) return true; 1892 1893 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) { 1894 // ... the address of an object with static storage duration, 1895 if (const VarDecl *VD = dyn_cast<VarDecl>(D)) 1896 return VD->hasGlobalStorage(); 1897 // ... the address of a function, 1898 // ... the address of a GUID [MS extension], 1899 return isa<FunctionDecl>(D) || isa<MSGuidDecl>(D); 1900 } 1901 1902 if (B.is<TypeInfoLValue>() || B.is<DynamicAllocLValue>()) 1903 return true; 1904 1905 const Expr *E = B.get<const Expr*>(); 1906 switch (E->getStmtClass()) { 1907 default: 1908 return false; 1909 case Expr::CompoundLiteralExprClass: { 1910 const CompoundLiteralExpr *CLE = cast<CompoundLiteralExpr>(E); 1911 return CLE->isFileScope() && CLE->isLValue(); 1912 } 1913 case Expr::MaterializeTemporaryExprClass: 1914 // A materialized temporary might have been lifetime-extended to static 1915 // storage duration. 1916 return cast<MaterializeTemporaryExpr>(E)->getStorageDuration() == SD_Static; 1917 // A string literal has static storage duration. 1918 case Expr::StringLiteralClass: 1919 case Expr::PredefinedExprClass: 1920 case Expr::ObjCStringLiteralClass: 1921 case Expr::ObjCEncodeExprClass: 1922 return true; 1923 case Expr::ObjCBoxedExprClass: 1924 return cast<ObjCBoxedExpr>(E)->isExpressibleAsConstantInitializer(); 1925 case Expr::CallExprClass: 1926 return IsStringLiteralCall(cast<CallExpr>(E)); 1927 // For GCC compatibility, &&label has static storage duration. 1928 case Expr::AddrLabelExprClass: 1929 return true; 1930 // A Block literal expression may be used as the initialization value for 1931 // Block variables at global or local static scope. 1932 case Expr::BlockExprClass: 1933 return !cast<BlockExpr>(E)->getBlockDecl()->hasCaptures(); 1934 case Expr::ImplicitValueInitExprClass: 1935 // FIXME: 1936 // We can never form an lvalue with an implicit value initialization as its 1937 // base through expression evaluation, so these only appear in one case: the 1938 // implicit variable declaration we invent when checking whether a constexpr 1939 // constructor can produce a constant expression. We must assume that such 1940 // an expression might be a global lvalue. 1941 return true; 1942 } 1943 } 1944 1945 static const ValueDecl *GetLValueBaseDecl(const LValue &LVal) { 1946 return LVal.Base.dyn_cast<const ValueDecl*>(); 1947 } 1948 1949 static bool IsLiteralLValue(const LValue &Value) { 1950 if (Value.getLValueCallIndex()) 1951 return false; 1952 const Expr *E = Value.Base.dyn_cast<const Expr*>(); 1953 return E && !isa<MaterializeTemporaryExpr>(E); 1954 } 1955 1956 static bool IsWeakLValue(const LValue &Value) { 1957 const ValueDecl *Decl = GetLValueBaseDecl(Value); 1958 return Decl && Decl->isWeak(); 1959 } 1960 1961 static bool isZeroSized(const LValue &Value) { 1962 const ValueDecl *Decl = GetLValueBaseDecl(Value); 1963 if (Decl && isa<VarDecl>(Decl)) { 1964 QualType Ty = Decl->getType(); 1965 if (Ty->isArrayType()) 1966 return Ty->isIncompleteType() || 1967 Decl->getASTContext().getTypeSize(Ty) == 0; 1968 } 1969 return false; 1970 } 1971 1972 static bool HasSameBase(const LValue &A, const LValue &B) { 1973 if (!A.getLValueBase()) 1974 return !B.getLValueBase(); 1975 if (!B.getLValueBase()) 1976 return false; 1977 1978 if (A.getLValueBase().getOpaqueValue() != 1979 B.getLValueBase().getOpaqueValue()) { 1980 const Decl *ADecl = GetLValueBaseDecl(A); 1981 if (!ADecl) 1982 return false; 1983 const Decl *BDecl = GetLValueBaseDecl(B); 1984 if (!BDecl || ADecl->getCanonicalDecl() != BDecl->getCanonicalDecl()) 1985 return false; 1986 } 1987 1988 return IsGlobalLValue(A.getLValueBase()) || 1989 (A.getLValueCallIndex() == B.getLValueCallIndex() && 1990 A.getLValueVersion() == B.getLValueVersion()); 1991 } 1992 1993 static void NoteLValueLocation(EvalInfo &Info, APValue::LValueBase Base) { 1994 assert(Base && "no location for a null lvalue"); 1995 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>(); 1996 if (VD) 1997 Info.Note(VD->getLocation(), diag::note_declared_at); 1998 else if (const Expr *E = Base.dyn_cast<const Expr*>()) 1999 Info.Note(E->getExprLoc(), diag::note_constexpr_temporary_here); 2000 else if (DynamicAllocLValue DA = Base.dyn_cast<DynamicAllocLValue>()) { 2001 // FIXME: Produce a note for dangling pointers too. 2002 if (Optional<DynAlloc*> Alloc = Info.lookupDynamicAlloc(DA)) 2003 Info.Note((*Alloc)->AllocExpr->getExprLoc(), 2004 diag::note_constexpr_dynamic_alloc_here); 2005 } 2006 // We have no information to show for a typeid(T) object. 2007 } 2008 2009 enum class CheckEvaluationResultKind { 2010 ConstantExpression, 2011 FullyInitialized, 2012 }; 2013 2014 /// Materialized temporaries that we've already checked to determine if they're 2015 /// initializsed by a constant expression. 2016 using CheckedTemporaries = 2017 llvm::SmallPtrSet<const MaterializeTemporaryExpr *, 8>; 2018 2019 static bool CheckEvaluationResult(CheckEvaluationResultKind CERK, 2020 EvalInfo &Info, SourceLocation DiagLoc, 2021 QualType Type, const APValue &Value, 2022 Expr::ConstExprUsage Usage, 2023 SourceLocation SubobjectLoc, 2024 CheckedTemporaries &CheckedTemps); 2025 2026 /// Check that this reference or pointer core constant expression is a valid 2027 /// value for an address or reference constant expression. Return true if we 2028 /// can fold this expression, whether or not it's a constant expression. 2029 static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc, 2030 QualType Type, const LValue &LVal, 2031 Expr::ConstExprUsage Usage, 2032 CheckedTemporaries &CheckedTemps) { 2033 bool IsReferenceType = Type->isReferenceType(); 2034 2035 APValue::LValueBase Base = LVal.getLValueBase(); 2036 const SubobjectDesignator &Designator = LVal.getLValueDesignator(); 2037 2038 if (auto *VD = LVal.getLValueBase().dyn_cast<const ValueDecl *>()) { 2039 if (auto *FD = dyn_cast<FunctionDecl>(VD)) { 2040 if (FD->isConsteval()) { 2041 Info.FFDiag(Loc, diag::note_consteval_address_accessible) 2042 << !Type->isAnyPointerType(); 2043 Info.Note(FD->getLocation(), diag::note_declared_at); 2044 return false; 2045 } 2046 } 2047 } 2048 2049 // Check that the object is a global. Note that the fake 'this' object we 2050 // manufacture when checking potential constant expressions is conservatively 2051 // assumed to be global here. 2052 if (!IsGlobalLValue(Base)) { 2053 if (Info.getLangOpts().CPlusPlus11) { 2054 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>(); 2055 Info.FFDiag(Loc, diag::note_constexpr_non_global, 1) 2056 << IsReferenceType << !Designator.Entries.empty() 2057 << !!VD << VD; 2058 NoteLValueLocation(Info, Base); 2059 } else { 2060 Info.FFDiag(Loc); 2061 } 2062 // Don't allow references to temporaries to escape. 2063 return false; 2064 } 2065 assert((Info.checkingPotentialConstantExpression() || 2066 LVal.getLValueCallIndex() == 0) && 2067 "have call index for global lvalue"); 2068 2069 if (Base.is<DynamicAllocLValue>()) { 2070 Info.FFDiag(Loc, diag::note_constexpr_dynamic_alloc) 2071 << IsReferenceType << !Designator.Entries.empty(); 2072 NoteLValueLocation(Info, Base); 2073 return false; 2074 } 2075 2076 if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>()) { 2077 if (const VarDecl *Var = dyn_cast<const VarDecl>(VD)) { 2078 // Check if this is a thread-local variable. 2079 if (Var->getTLSKind()) 2080 // FIXME: Diagnostic! 2081 return false; 2082 2083 // A dllimport variable never acts like a constant. 2084 if (Usage == Expr::EvaluateForCodeGen && Var->hasAttr<DLLImportAttr>()) 2085 // FIXME: Diagnostic! 2086 return false; 2087 } 2088 if (const auto *FD = dyn_cast<const FunctionDecl>(VD)) { 2089 // __declspec(dllimport) must be handled very carefully: 2090 // We must never initialize an expression with the thunk in C++. 2091 // Doing otherwise would allow the same id-expression to yield 2092 // different addresses for the same function in different translation 2093 // units. However, this means that we must dynamically initialize the 2094 // expression with the contents of the import address table at runtime. 2095 // 2096 // The C language has no notion of ODR; furthermore, it has no notion of 2097 // dynamic initialization. This means that we are permitted to 2098 // perform initialization with the address of the thunk. 2099 if (Info.getLangOpts().CPlusPlus && Usage == Expr::EvaluateForCodeGen && 2100 FD->hasAttr<DLLImportAttr>()) 2101 // FIXME: Diagnostic! 2102 return false; 2103 } 2104 } else if (const auto *MTE = dyn_cast_or_null<MaterializeTemporaryExpr>( 2105 Base.dyn_cast<const Expr *>())) { 2106 if (CheckedTemps.insert(MTE).second) { 2107 QualType TempType = getType(Base); 2108 if (TempType.isDestructedType()) { 2109 Info.FFDiag(MTE->getExprLoc(), 2110 diag::note_constexpr_unsupported_tempoarary_nontrivial_dtor) 2111 << TempType; 2112 return false; 2113 } 2114 2115 APValue *V = MTE->getOrCreateValue(false); 2116 assert(V && "evasluation result refers to uninitialised temporary"); 2117 if (!CheckEvaluationResult(CheckEvaluationResultKind::ConstantExpression, 2118 Info, MTE->getExprLoc(), TempType, *V, 2119 Usage, SourceLocation(), CheckedTemps)) 2120 return false; 2121 } 2122 } 2123 2124 // Allow address constant expressions to be past-the-end pointers. This is 2125 // an extension: the standard requires them to point to an object. 2126 if (!IsReferenceType) 2127 return true; 2128 2129 // A reference constant expression must refer to an object. 2130 if (!Base) { 2131 // FIXME: diagnostic 2132 Info.CCEDiag(Loc); 2133 return true; 2134 } 2135 2136 // Does this refer one past the end of some object? 2137 if (!Designator.Invalid && Designator.isOnePastTheEnd()) { 2138 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>(); 2139 Info.FFDiag(Loc, diag::note_constexpr_past_end, 1) 2140 << !Designator.Entries.empty() << !!VD << VD; 2141 NoteLValueLocation(Info, Base); 2142 } 2143 2144 return true; 2145 } 2146 2147 /// Member pointers are constant expressions unless they point to a 2148 /// non-virtual dllimport member function. 2149 static bool CheckMemberPointerConstantExpression(EvalInfo &Info, 2150 SourceLocation Loc, 2151 QualType Type, 2152 const APValue &Value, 2153 Expr::ConstExprUsage Usage) { 2154 const ValueDecl *Member = Value.getMemberPointerDecl(); 2155 const auto *FD = dyn_cast_or_null<CXXMethodDecl>(Member); 2156 if (!FD) 2157 return true; 2158 if (FD->isConsteval()) { 2159 Info.FFDiag(Loc, diag::note_consteval_address_accessible) << /*pointer*/ 0; 2160 Info.Note(FD->getLocation(), diag::note_declared_at); 2161 return false; 2162 } 2163 return Usage == Expr::EvaluateForMangling || FD->isVirtual() || 2164 !FD->hasAttr<DLLImportAttr>(); 2165 } 2166 2167 /// Check that this core constant expression is of literal type, and if not, 2168 /// produce an appropriate diagnostic. 2169 static bool CheckLiteralType(EvalInfo &Info, const Expr *E, 2170 const LValue *This = nullptr) { 2171 if (!E->isRValue() || E->getType()->isLiteralType(Info.Ctx)) 2172 return true; 2173 2174 // C++1y: A constant initializer for an object o [...] may also invoke 2175 // constexpr constructors for o and its subobjects even if those objects 2176 // are of non-literal class types. 2177 // 2178 // C++11 missed this detail for aggregates, so classes like this: 2179 // struct foo_t { union { int i; volatile int j; } u; }; 2180 // are not (obviously) initializable like so: 2181 // __attribute__((__require_constant_initialization__)) 2182 // static const foo_t x = {{0}}; 2183 // because "i" is a subobject with non-literal initialization (due to the 2184 // volatile member of the union). See: 2185 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1677 2186 // Therefore, we use the C++1y behavior. 2187 if (This && Info.EvaluatingDecl == This->getLValueBase()) 2188 return true; 2189 2190 // Prvalue constant expressions must be of literal types. 2191 if (Info.getLangOpts().CPlusPlus11) 2192 Info.FFDiag(E, diag::note_constexpr_nonliteral) 2193 << E->getType(); 2194 else 2195 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr); 2196 return false; 2197 } 2198 2199 static bool CheckEvaluationResult(CheckEvaluationResultKind CERK, 2200 EvalInfo &Info, SourceLocation DiagLoc, 2201 QualType Type, const APValue &Value, 2202 Expr::ConstExprUsage Usage, 2203 SourceLocation SubobjectLoc, 2204 CheckedTemporaries &CheckedTemps) { 2205 if (!Value.hasValue()) { 2206 Info.FFDiag(DiagLoc, diag::note_constexpr_uninitialized) 2207 << true << Type; 2208 if (SubobjectLoc.isValid()) 2209 Info.Note(SubobjectLoc, diag::note_constexpr_subobject_declared_here); 2210 return false; 2211 } 2212 2213 // We allow _Atomic(T) to be initialized from anything that T can be 2214 // initialized from. 2215 if (const AtomicType *AT = Type->getAs<AtomicType>()) 2216 Type = AT->getValueType(); 2217 2218 // Core issue 1454: For a literal constant expression of array or class type, 2219 // each subobject of its value shall have been initialized by a constant 2220 // expression. 2221 if (Value.isArray()) { 2222 QualType EltTy = Type->castAsArrayTypeUnsafe()->getElementType(); 2223 for (unsigned I = 0, N = Value.getArrayInitializedElts(); I != N; ++I) { 2224 if (!CheckEvaluationResult(CERK, Info, DiagLoc, EltTy, 2225 Value.getArrayInitializedElt(I), Usage, 2226 SubobjectLoc, CheckedTemps)) 2227 return false; 2228 } 2229 if (!Value.hasArrayFiller()) 2230 return true; 2231 return CheckEvaluationResult(CERK, Info, DiagLoc, EltTy, 2232 Value.getArrayFiller(), Usage, SubobjectLoc, 2233 CheckedTemps); 2234 } 2235 if (Value.isUnion() && Value.getUnionField()) { 2236 return CheckEvaluationResult( 2237 CERK, Info, DiagLoc, Value.getUnionField()->getType(), 2238 Value.getUnionValue(), Usage, Value.getUnionField()->getLocation(), 2239 CheckedTemps); 2240 } 2241 if (Value.isStruct()) { 2242 RecordDecl *RD = Type->castAs<RecordType>()->getDecl(); 2243 if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) { 2244 unsigned BaseIndex = 0; 2245 for (const CXXBaseSpecifier &BS : CD->bases()) { 2246 if (!CheckEvaluationResult(CERK, Info, DiagLoc, BS.getType(), 2247 Value.getStructBase(BaseIndex), Usage, 2248 BS.getBeginLoc(), CheckedTemps)) 2249 return false; 2250 ++BaseIndex; 2251 } 2252 } 2253 for (const auto *I : RD->fields()) { 2254 if (I->isUnnamedBitfield()) 2255 continue; 2256 2257 if (!CheckEvaluationResult(CERK, Info, DiagLoc, I->getType(), 2258 Value.getStructField(I->getFieldIndex()), 2259 Usage, I->getLocation(), CheckedTemps)) 2260 return false; 2261 } 2262 } 2263 2264 if (Value.isLValue() && 2265 CERK == CheckEvaluationResultKind::ConstantExpression) { 2266 LValue LVal; 2267 LVal.setFrom(Info.Ctx, Value); 2268 return CheckLValueConstantExpression(Info, DiagLoc, Type, LVal, Usage, 2269 CheckedTemps); 2270 } 2271 2272 if (Value.isMemberPointer() && 2273 CERK == CheckEvaluationResultKind::ConstantExpression) 2274 return CheckMemberPointerConstantExpression(Info, DiagLoc, Type, Value, Usage); 2275 2276 // Everything else is fine. 2277 return true; 2278 } 2279 2280 /// Check that this core constant expression value is a valid value for a 2281 /// constant expression. If not, report an appropriate diagnostic. Does not 2282 /// check that the expression is of literal type. 2283 static bool 2284 CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc, QualType Type, 2285 const APValue &Value, 2286 Expr::ConstExprUsage Usage = Expr::EvaluateForCodeGen) { 2287 CheckedTemporaries CheckedTemps; 2288 return CheckEvaluationResult(CheckEvaluationResultKind::ConstantExpression, 2289 Info, DiagLoc, Type, Value, Usage, 2290 SourceLocation(), CheckedTemps); 2291 } 2292 2293 /// Check that this evaluated value is fully-initialized and can be loaded by 2294 /// an lvalue-to-rvalue conversion. 2295 static bool CheckFullyInitialized(EvalInfo &Info, SourceLocation DiagLoc, 2296 QualType Type, const APValue &Value) { 2297 CheckedTemporaries CheckedTemps; 2298 return CheckEvaluationResult( 2299 CheckEvaluationResultKind::FullyInitialized, Info, DiagLoc, Type, Value, 2300 Expr::EvaluateForCodeGen, SourceLocation(), CheckedTemps); 2301 } 2302 2303 /// Enforce C++2a [expr.const]/4.17, which disallows new-expressions unless 2304 /// "the allocated storage is deallocated within the evaluation". 2305 static bool CheckMemoryLeaks(EvalInfo &Info) { 2306 if (!Info.HeapAllocs.empty()) { 2307 // We can still fold to a constant despite a compile-time memory leak, 2308 // so long as the heap allocation isn't referenced in the result (we check 2309 // that in CheckConstantExpression). 2310 Info.CCEDiag(Info.HeapAllocs.begin()->second.AllocExpr, 2311 diag::note_constexpr_memory_leak) 2312 << unsigned(Info.HeapAllocs.size() - 1); 2313 } 2314 return true; 2315 } 2316 2317 static bool EvalPointerValueAsBool(const APValue &Value, bool &Result) { 2318 // A null base expression indicates a null pointer. These are always 2319 // evaluatable, and they are false unless the offset is zero. 2320 if (!Value.getLValueBase()) { 2321 Result = !Value.getLValueOffset().isZero(); 2322 return true; 2323 } 2324 2325 // We have a non-null base. These are generally known to be true, but if it's 2326 // a weak declaration it can be null at runtime. 2327 Result = true; 2328 const ValueDecl *Decl = Value.getLValueBase().dyn_cast<const ValueDecl*>(); 2329 return !Decl || !Decl->isWeak(); 2330 } 2331 2332 static bool HandleConversionToBool(const APValue &Val, bool &Result) { 2333 switch (Val.getKind()) { 2334 case APValue::None: 2335 case APValue::Indeterminate: 2336 return false; 2337 case APValue::Int: 2338 Result = Val.getInt().getBoolValue(); 2339 return true; 2340 case APValue::FixedPoint: 2341 Result = Val.getFixedPoint().getBoolValue(); 2342 return true; 2343 case APValue::Float: 2344 Result = !Val.getFloat().isZero(); 2345 return true; 2346 case APValue::ComplexInt: 2347 Result = Val.getComplexIntReal().getBoolValue() || 2348 Val.getComplexIntImag().getBoolValue(); 2349 return true; 2350 case APValue::ComplexFloat: 2351 Result = !Val.getComplexFloatReal().isZero() || 2352 !Val.getComplexFloatImag().isZero(); 2353 return true; 2354 case APValue::LValue: 2355 return EvalPointerValueAsBool(Val, Result); 2356 case APValue::MemberPointer: 2357 Result = Val.getMemberPointerDecl(); 2358 return true; 2359 case APValue::Vector: 2360 case APValue::Array: 2361 case APValue::Struct: 2362 case APValue::Union: 2363 case APValue::AddrLabelDiff: 2364 return false; 2365 } 2366 2367 llvm_unreachable("unknown APValue kind"); 2368 } 2369 2370 static bool EvaluateAsBooleanCondition(const Expr *E, bool &Result, 2371 EvalInfo &Info) { 2372 assert(E->isRValue() && "missing lvalue-to-rvalue conv in bool condition"); 2373 APValue Val; 2374 if (!Evaluate(Val, Info, E)) 2375 return false; 2376 return HandleConversionToBool(Val, Result); 2377 } 2378 2379 template<typename T> 2380 static bool HandleOverflow(EvalInfo &Info, const Expr *E, 2381 const T &SrcValue, QualType DestType) { 2382 Info.CCEDiag(E, diag::note_constexpr_overflow) 2383 << SrcValue << DestType; 2384 return Info.noteUndefinedBehavior(); 2385 } 2386 2387 static bool HandleFloatToIntCast(EvalInfo &Info, const Expr *E, 2388 QualType SrcType, const APFloat &Value, 2389 QualType DestType, APSInt &Result) { 2390 unsigned DestWidth = Info.Ctx.getIntWidth(DestType); 2391 // Determine whether we are converting to unsigned or signed. 2392 bool DestSigned = DestType->isSignedIntegerOrEnumerationType(); 2393 2394 Result = APSInt(DestWidth, !DestSigned); 2395 bool ignored; 2396 if (Value.convertToInteger(Result, llvm::APFloat::rmTowardZero, &ignored) 2397 & APFloat::opInvalidOp) 2398 return HandleOverflow(Info, E, Value, DestType); 2399 return true; 2400 } 2401 2402 static bool HandleFloatToFloatCast(EvalInfo &Info, const Expr *E, 2403 QualType SrcType, QualType DestType, 2404 APFloat &Result) { 2405 APFloat Value = Result; 2406 bool ignored; 2407 Result.convert(Info.Ctx.getFloatTypeSemantics(DestType), 2408 APFloat::rmNearestTiesToEven, &ignored); 2409 return true; 2410 } 2411 2412 static APSInt HandleIntToIntCast(EvalInfo &Info, const Expr *E, 2413 QualType DestType, QualType SrcType, 2414 const APSInt &Value) { 2415 unsigned DestWidth = Info.Ctx.getIntWidth(DestType); 2416 // Figure out if this is a truncate, extend or noop cast. 2417 // If the input is signed, do a sign extend, noop, or truncate. 2418 APSInt Result = Value.extOrTrunc(DestWidth); 2419 Result.setIsUnsigned(DestType->isUnsignedIntegerOrEnumerationType()); 2420 if (DestType->isBooleanType()) 2421 Result = Value.getBoolValue(); 2422 return Result; 2423 } 2424 2425 static bool HandleIntToFloatCast(EvalInfo &Info, const Expr *E, 2426 QualType SrcType, const APSInt &Value, 2427 QualType DestType, APFloat &Result) { 2428 Result = APFloat(Info.Ctx.getFloatTypeSemantics(DestType), 1); 2429 Result.convertFromAPInt(Value, Value.isSigned(), 2430 APFloat::rmNearestTiesToEven); 2431 return true; 2432 } 2433 2434 static bool truncateBitfieldValue(EvalInfo &Info, const Expr *E, 2435 APValue &Value, const FieldDecl *FD) { 2436 assert(FD->isBitField() && "truncateBitfieldValue on non-bitfield"); 2437 2438 if (!Value.isInt()) { 2439 // Trying to store a pointer-cast-to-integer into a bitfield. 2440 // FIXME: In this case, we should provide the diagnostic for casting 2441 // a pointer to an integer. 2442 assert(Value.isLValue() && "integral value neither int nor lvalue?"); 2443 Info.FFDiag(E); 2444 return false; 2445 } 2446 2447 APSInt &Int = Value.getInt(); 2448 unsigned OldBitWidth = Int.getBitWidth(); 2449 unsigned NewBitWidth = FD->getBitWidthValue(Info.Ctx); 2450 if (NewBitWidth < OldBitWidth) 2451 Int = Int.trunc(NewBitWidth).extend(OldBitWidth); 2452 return true; 2453 } 2454 2455 static bool EvalAndBitcastToAPInt(EvalInfo &Info, const Expr *E, 2456 llvm::APInt &Res) { 2457 APValue SVal; 2458 if (!Evaluate(SVal, Info, E)) 2459 return false; 2460 if (SVal.isInt()) { 2461 Res = SVal.getInt(); 2462 return true; 2463 } 2464 if (SVal.isFloat()) { 2465 Res = SVal.getFloat().bitcastToAPInt(); 2466 return true; 2467 } 2468 if (SVal.isVector()) { 2469 QualType VecTy = E->getType(); 2470 unsigned VecSize = Info.Ctx.getTypeSize(VecTy); 2471 QualType EltTy = VecTy->castAs<VectorType>()->getElementType(); 2472 unsigned EltSize = Info.Ctx.getTypeSize(EltTy); 2473 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian(); 2474 Res = llvm::APInt::getNullValue(VecSize); 2475 for (unsigned i = 0; i < SVal.getVectorLength(); i++) { 2476 APValue &Elt = SVal.getVectorElt(i); 2477 llvm::APInt EltAsInt; 2478 if (Elt.isInt()) { 2479 EltAsInt = Elt.getInt(); 2480 } else if (Elt.isFloat()) { 2481 EltAsInt = Elt.getFloat().bitcastToAPInt(); 2482 } else { 2483 // Don't try to handle vectors of anything other than int or float 2484 // (not sure if it's possible to hit this case). 2485 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr); 2486 return false; 2487 } 2488 unsigned BaseEltSize = EltAsInt.getBitWidth(); 2489 if (BigEndian) 2490 Res |= EltAsInt.zextOrTrunc(VecSize).rotr(i*EltSize+BaseEltSize); 2491 else 2492 Res |= EltAsInt.zextOrTrunc(VecSize).rotl(i*EltSize); 2493 } 2494 return true; 2495 } 2496 // Give up if the input isn't an int, float, or vector. For example, we 2497 // reject "(v4i16)(intptr_t)&a". 2498 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr); 2499 return false; 2500 } 2501 2502 /// Perform the given integer operation, which is known to need at most BitWidth 2503 /// bits, and check for overflow in the original type (if that type was not an 2504 /// unsigned type). 2505 template<typename Operation> 2506 static bool CheckedIntArithmetic(EvalInfo &Info, const Expr *E, 2507 const APSInt &LHS, const APSInt &RHS, 2508 unsigned BitWidth, Operation Op, 2509 APSInt &Result) { 2510 if (LHS.isUnsigned()) { 2511 Result = Op(LHS, RHS); 2512 return true; 2513 } 2514 2515 APSInt Value(Op(LHS.extend(BitWidth), RHS.extend(BitWidth)), false); 2516 Result = Value.trunc(LHS.getBitWidth()); 2517 if (Result.extend(BitWidth) != Value) { 2518 if (Info.checkingForUndefinedBehavior()) 2519 Info.Ctx.getDiagnostics().Report(E->getExprLoc(), 2520 diag::warn_integer_constant_overflow) 2521 << Result.toString(10) << E->getType(); 2522 else 2523 return HandleOverflow(Info, E, Value, E->getType()); 2524 } 2525 return true; 2526 } 2527 2528 /// Perform the given binary integer operation. 2529 static bool handleIntIntBinOp(EvalInfo &Info, const Expr *E, const APSInt &LHS, 2530 BinaryOperatorKind Opcode, APSInt RHS, 2531 APSInt &Result) { 2532 switch (Opcode) { 2533 default: 2534 Info.FFDiag(E); 2535 return false; 2536 case BO_Mul: 2537 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() * 2, 2538 std::multiplies<APSInt>(), Result); 2539 case BO_Add: 2540 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1, 2541 std::plus<APSInt>(), Result); 2542 case BO_Sub: 2543 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1, 2544 std::minus<APSInt>(), Result); 2545 case BO_And: Result = LHS & RHS; return true; 2546 case BO_Xor: Result = LHS ^ RHS; return true; 2547 case BO_Or: Result = LHS | RHS; return true; 2548 case BO_Div: 2549 case BO_Rem: 2550 if (RHS == 0) { 2551 Info.FFDiag(E, diag::note_expr_divide_by_zero); 2552 return false; 2553 } 2554 Result = (Opcode == BO_Rem ? LHS % RHS : LHS / RHS); 2555 // Check for overflow case: INT_MIN / -1 or INT_MIN % -1. APSInt supports 2556 // this operation and gives the two's complement result. 2557 if (RHS.isNegative() && RHS.isAllOnesValue() && 2558 LHS.isSigned() && LHS.isMinSignedValue()) 2559 return HandleOverflow(Info, E, -LHS.extend(LHS.getBitWidth() + 1), 2560 E->getType()); 2561 return true; 2562 case BO_Shl: { 2563 if (Info.getLangOpts().OpenCL) 2564 // OpenCL 6.3j: shift values are effectively % word size of LHS. 2565 RHS &= APSInt(llvm::APInt(RHS.getBitWidth(), 2566 static_cast<uint64_t>(LHS.getBitWidth() - 1)), 2567 RHS.isUnsigned()); 2568 else if (RHS.isSigned() && RHS.isNegative()) { 2569 // During constant-folding, a negative shift is an opposite shift. Such 2570 // a shift is not a constant expression. 2571 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS; 2572 RHS = -RHS; 2573 goto shift_right; 2574 } 2575 shift_left: 2576 // C++11 [expr.shift]p1: Shift width must be less than the bit width of 2577 // the shifted type. 2578 unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1); 2579 if (SA != RHS) { 2580 Info.CCEDiag(E, diag::note_constexpr_large_shift) 2581 << RHS << E->getType() << LHS.getBitWidth(); 2582 } else if (LHS.isSigned() && !Info.getLangOpts().CPlusPlus20) { 2583 // C++11 [expr.shift]p2: A signed left shift must have a non-negative 2584 // operand, and must not overflow the corresponding unsigned type. 2585 // C++2a [expr.shift]p2: E1 << E2 is the unique value congruent to 2586 // E1 x 2^E2 module 2^N. 2587 if (LHS.isNegative()) 2588 Info.CCEDiag(E, diag::note_constexpr_lshift_of_negative) << LHS; 2589 else if (LHS.countLeadingZeros() < SA) 2590 Info.CCEDiag(E, diag::note_constexpr_lshift_discards); 2591 } 2592 Result = LHS << SA; 2593 return true; 2594 } 2595 case BO_Shr: { 2596 if (Info.getLangOpts().OpenCL) 2597 // OpenCL 6.3j: shift values are effectively % word size of LHS. 2598 RHS &= APSInt(llvm::APInt(RHS.getBitWidth(), 2599 static_cast<uint64_t>(LHS.getBitWidth() - 1)), 2600 RHS.isUnsigned()); 2601 else if (RHS.isSigned() && RHS.isNegative()) { 2602 // During constant-folding, a negative shift is an opposite shift. Such a 2603 // shift is not a constant expression. 2604 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS; 2605 RHS = -RHS; 2606 goto shift_left; 2607 } 2608 shift_right: 2609 // C++11 [expr.shift]p1: Shift width must be less than the bit width of the 2610 // shifted type. 2611 unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1); 2612 if (SA != RHS) 2613 Info.CCEDiag(E, diag::note_constexpr_large_shift) 2614 << RHS << E->getType() << LHS.getBitWidth(); 2615 Result = LHS >> SA; 2616 return true; 2617 } 2618 2619 case BO_LT: Result = LHS < RHS; return true; 2620 case BO_GT: Result = LHS > RHS; return true; 2621 case BO_LE: Result = LHS <= RHS; return true; 2622 case BO_GE: Result = LHS >= RHS; return true; 2623 case BO_EQ: Result = LHS == RHS; return true; 2624 case BO_NE: Result = LHS != RHS; return true; 2625 case BO_Cmp: 2626 llvm_unreachable("BO_Cmp should be handled elsewhere"); 2627 } 2628 } 2629 2630 /// Perform the given binary floating-point operation, in-place, on LHS. 2631 static bool handleFloatFloatBinOp(EvalInfo &Info, const Expr *E, 2632 APFloat &LHS, BinaryOperatorKind Opcode, 2633 const APFloat &RHS) { 2634 switch (Opcode) { 2635 default: 2636 Info.FFDiag(E); 2637 return false; 2638 case BO_Mul: 2639 LHS.multiply(RHS, APFloat::rmNearestTiesToEven); 2640 break; 2641 case BO_Add: 2642 LHS.add(RHS, APFloat::rmNearestTiesToEven); 2643 break; 2644 case BO_Sub: 2645 LHS.subtract(RHS, APFloat::rmNearestTiesToEven); 2646 break; 2647 case BO_Div: 2648 // [expr.mul]p4: 2649 // If the second operand of / or % is zero the behavior is undefined. 2650 if (RHS.isZero()) 2651 Info.CCEDiag(E, diag::note_expr_divide_by_zero); 2652 LHS.divide(RHS, APFloat::rmNearestTiesToEven); 2653 break; 2654 } 2655 2656 // [expr.pre]p4: 2657 // If during the evaluation of an expression, the result is not 2658 // mathematically defined [...], the behavior is undefined. 2659 // FIXME: C++ rules require us to not conform to IEEE 754 here. 2660 if (LHS.isNaN()) { 2661 Info.CCEDiag(E, diag::note_constexpr_float_arithmetic) << LHS.isNaN(); 2662 return Info.noteUndefinedBehavior(); 2663 } 2664 return true; 2665 } 2666 2667 static bool handleLogicalOpForVector(const APInt &LHSValue, 2668 BinaryOperatorKind Opcode, 2669 const APInt &RHSValue, APInt &Result) { 2670 bool LHS = (LHSValue != 0); 2671 bool RHS = (RHSValue != 0); 2672 2673 if (Opcode == BO_LAnd) 2674 Result = LHS && RHS; 2675 else 2676 Result = LHS || RHS; 2677 return true; 2678 } 2679 static bool handleLogicalOpForVector(const APFloat &LHSValue, 2680 BinaryOperatorKind Opcode, 2681 const APFloat &RHSValue, APInt &Result) { 2682 bool LHS = !LHSValue.isZero(); 2683 bool RHS = !RHSValue.isZero(); 2684 2685 if (Opcode == BO_LAnd) 2686 Result = LHS && RHS; 2687 else 2688 Result = LHS || RHS; 2689 return true; 2690 } 2691 2692 static bool handleLogicalOpForVector(const APValue &LHSValue, 2693 BinaryOperatorKind Opcode, 2694 const APValue &RHSValue, APInt &Result) { 2695 // The result is always an int type, however operands match the first. 2696 if (LHSValue.getKind() == APValue::Int) 2697 return handleLogicalOpForVector(LHSValue.getInt(), Opcode, 2698 RHSValue.getInt(), Result); 2699 assert(LHSValue.getKind() == APValue::Float && "Should be no other options"); 2700 return handleLogicalOpForVector(LHSValue.getFloat(), Opcode, 2701 RHSValue.getFloat(), Result); 2702 } 2703 2704 template <typename APTy> 2705 static bool 2706 handleCompareOpForVectorHelper(const APTy &LHSValue, BinaryOperatorKind Opcode, 2707 const APTy &RHSValue, APInt &Result) { 2708 switch (Opcode) { 2709 default: 2710 llvm_unreachable("unsupported binary operator"); 2711 case BO_EQ: 2712 Result = (LHSValue == RHSValue); 2713 break; 2714 case BO_NE: 2715 Result = (LHSValue != RHSValue); 2716 break; 2717 case BO_LT: 2718 Result = (LHSValue < RHSValue); 2719 break; 2720 case BO_GT: 2721 Result = (LHSValue > RHSValue); 2722 break; 2723 case BO_LE: 2724 Result = (LHSValue <= RHSValue); 2725 break; 2726 case BO_GE: 2727 Result = (LHSValue >= RHSValue); 2728 break; 2729 } 2730 2731 return true; 2732 } 2733 2734 static bool handleCompareOpForVector(const APValue &LHSValue, 2735 BinaryOperatorKind Opcode, 2736 const APValue &RHSValue, APInt &Result) { 2737 // The result is always an int type, however operands match the first. 2738 if (LHSValue.getKind() == APValue::Int) 2739 return handleCompareOpForVectorHelper(LHSValue.getInt(), Opcode, 2740 RHSValue.getInt(), Result); 2741 assert(LHSValue.getKind() == APValue::Float && "Should be no other options"); 2742 return handleCompareOpForVectorHelper(LHSValue.getFloat(), Opcode, 2743 RHSValue.getFloat(), Result); 2744 } 2745 2746 // Perform binary operations for vector types, in place on the LHS. 2747 static bool handleVectorVectorBinOp(EvalInfo &Info, const Expr *E, 2748 BinaryOperatorKind Opcode, 2749 APValue &LHSValue, 2750 const APValue &RHSValue) { 2751 assert(Opcode != BO_PtrMemD && Opcode != BO_PtrMemI && 2752 "Operation not supported on vector types"); 2753 2754 const auto *VT = E->getType()->castAs<VectorType>(); 2755 unsigned NumElements = VT->getNumElements(); 2756 QualType EltTy = VT->getElementType(); 2757 2758 // In the cases (typically C as I've observed) where we aren't evaluating 2759 // constexpr but are checking for cases where the LHS isn't yet evaluatable, 2760 // just give up. 2761 if (!LHSValue.isVector()) { 2762 assert(LHSValue.isLValue() && 2763 "A vector result that isn't a vector OR uncalculated LValue"); 2764 Info.FFDiag(E); 2765 return false; 2766 } 2767 2768 assert(LHSValue.getVectorLength() == NumElements && 2769 RHSValue.getVectorLength() == NumElements && "Different vector sizes"); 2770 2771 SmallVector<APValue, 4> ResultElements; 2772 2773 for (unsigned EltNum = 0; EltNum < NumElements; ++EltNum) { 2774 APValue LHSElt = LHSValue.getVectorElt(EltNum); 2775 APValue RHSElt = RHSValue.getVectorElt(EltNum); 2776 2777 if (EltTy->isIntegerType()) { 2778 APSInt EltResult{Info.Ctx.getIntWidth(EltTy), 2779 EltTy->isUnsignedIntegerType()}; 2780 bool Success = true; 2781 2782 if (BinaryOperator::isLogicalOp(Opcode)) 2783 Success = handleLogicalOpForVector(LHSElt, Opcode, RHSElt, EltResult); 2784 else if (BinaryOperator::isComparisonOp(Opcode)) 2785 Success = handleCompareOpForVector(LHSElt, Opcode, RHSElt, EltResult); 2786 else 2787 Success = handleIntIntBinOp(Info, E, LHSElt.getInt(), Opcode, 2788 RHSElt.getInt(), EltResult); 2789 2790 if (!Success) { 2791 Info.FFDiag(E); 2792 return false; 2793 } 2794 ResultElements.emplace_back(EltResult); 2795 2796 } else if (EltTy->isFloatingType()) { 2797 assert(LHSElt.getKind() == APValue::Float && 2798 RHSElt.getKind() == APValue::Float && 2799 "Mismatched LHS/RHS/Result Type"); 2800 APFloat LHSFloat = LHSElt.getFloat(); 2801 2802 if (!handleFloatFloatBinOp(Info, E, LHSFloat, Opcode, 2803 RHSElt.getFloat())) { 2804 Info.FFDiag(E); 2805 return false; 2806 } 2807 2808 ResultElements.emplace_back(LHSFloat); 2809 } 2810 } 2811 2812 LHSValue = APValue(ResultElements.data(), ResultElements.size()); 2813 return true; 2814 } 2815 2816 /// Cast an lvalue referring to a base subobject to a derived class, by 2817 /// truncating the lvalue's path to the given length. 2818 static bool CastToDerivedClass(EvalInfo &Info, const Expr *E, LValue &Result, 2819 const RecordDecl *TruncatedType, 2820 unsigned TruncatedElements) { 2821 SubobjectDesignator &D = Result.Designator; 2822 2823 // Check we actually point to a derived class object. 2824 if (TruncatedElements == D.Entries.size()) 2825 return true; 2826 assert(TruncatedElements >= D.MostDerivedPathLength && 2827 "not casting to a derived class"); 2828 if (!Result.checkSubobject(Info, E, CSK_Derived)) 2829 return false; 2830 2831 // Truncate the path to the subobject, and remove any derived-to-base offsets. 2832 const RecordDecl *RD = TruncatedType; 2833 for (unsigned I = TruncatedElements, N = D.Entries.size(); I != N; ++I) { 2834 if (RD->isInvalidDecl()) return false; 2835 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); 2836 const CXXRecordDecl *Base = getAsBaseClass(D.Entries[I]); 2837 if (isVirtualBaseClass(D.Entries[I])) 2838 Result.Offset -= Layout.getVBaseClassOffset(Base); 2839 else 2840 Result.Offset -= Layout.getBaseClassOffset(Base); 2841 RD = Base; 2842 } 2843 D.Entries.resize(TruncatedElements); 2844 return true; 2845 } 2846 2847 static bool HandleLValueDirectBase(EvalInfo &Info, const Expr *E, LValue &Obj, 2848 const CXXRecordDecl *Derived, 2849 const CXXRecordDecl *Base, 2850 const ASTRecordLayout *RL = nullptr) { 2851 if (!RL) { 2852 if (Derived->isInvalidDecl()) return false; 2853 RL = &Info.Ctx.getASTRecordLayout(Derived); 2854 } 2855 2856 Obj.getLValueOffset() += RL->getBaseClassOffset(Base); 2857 Obj.addDecl(Info, E, Base, /*Virtual*/ false); 2858 return true; 2859 } 2860 2861 static bool HandleLValueBase(EvalInfo &Info, const Expr *E, LValue &Obj, 2862 const CXXRecordDecl *DerivedDecl, 2863 const CXXBaseSpecifier *Base) { 2864 const CXXRecordDecl *BaseDecl = Base->getType()->getAsCXXRecordDecl(); 2865 2866 if (!Base->isVirtual()) 2867 return HandleLValueDirectBase(Info, E, Obj, DerivedDecl, BaseDecl); 2868 2869 SubobjectDesignator &D = Obj.Designator; 2870 if (D.Invalid) 2871 return false; 2872 2873 // Extract most-derived object and corresponding type. 2874 DerivedDecl = D.MostDerivedType->getAsCXXRecordDecl(); 2875 if (!CastToDerivedClass(Info, E, Obj, DerivedDecl, D.MostDerivedPathLength)) 2876 return false; 2877 2878 // Find the virtual base class. 2879 if (DerivedDecl->isInvalidDecl()) return false; 2880 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(DerivedDecl); 2881 Obj.getLValueOffset() += Layout.getVBaseClassOffset(BaseDecl); 2882 Obj.addDecl(Info, E, BaseDecl, /*Virtual*/ true); 2883 return true; 2884 } 2885 2886 static bool HandleLValueBasePath(EvalInfo &Info, const CastExpr *E, 2887 QualType Type, LValue &Result) { 2888 for (CastExpr::path_const_iterator PathI = E->path_begin(), 2889 PathE = E->path_end(); 2890 PathI != PathE; ++PathI) { 2891 if (!HandleLValueBase(Info, E, Result, Type->getAsCXXRecordDecl(), 2892 *PathI)) 2893 return false; 2894 Type = (*PathI)->getType(); 2895 } 2896 return true; 2897 } 2898 2899 /// Cast an lvalue referring to a derived class to a known base subobject. 2900 static bool CastToBaseClass(EvalInfo &Info, const Expr *E, LValue &Result, 2901 const CXXRecordDecl *DerivedRD, 2902 const CXXRecordDecl *BaseRD) { 2903 CXXBasePaths Paths(/*FindAmbiguities=*/false, 2904 /*RecordPaths=*/true, /*DetectVirtual=*/false); 2905 if (!DerivedRD->isDerivedFrom(BaseRD, Paths)) 2906 llvm_unreachable("Class must be derived from the passed in base class!"); 2907 2908 for (CXXBasePathElement &Elem : Paths.front()) 2909 if (!HandleLValueBase(Info, E, Result, Elem.Class, Elem.Base)) 2910 return false; 2911 return true; 2912 } 2913 2914 /// Update LVal to refer to the given field, which must be a member of the type 2915 /// currently described by LVal. 2916 static bool HandleLValueMember(EvalInfo &Info, const Expr *E, LValue &LVal, 2917 const FieldDecl *FD, 2918 const ASTRecordLayout *RL = nullptr) { 2919 if (!RL) { 2920 if (FD->getParent()->isInvalidDecl()) return false; 2921 RL = &Info.Ctx.getASTRecordLayout(FD->getParent()); 2922 } 2923 2924 unsigned I = FD->getFieldIndex(); 2925 LVal.adjustOffset(Info.Ctx.toCharUnitsFromBits(RL->getFieldOffset(I))); 2926 LVal.addDecl(Info, E, FD); 2927 return true; 2928 } 2929 2930 /// Update LVal to refer to the given indirect field. 2931 static bool HandleLValueIndirectMember(EvalInfo &Info, const Expr *E, 2932 LValue &LVal, 2933 const IndirectFieldDecl *IFD) { 2934 for (const auto *C : IFD->chain()) 2935 if (!HandleLValueMember(Info, E, LVal, cast<FieldDecl>(C))) 2936 return false; 2937 return true; 2938 } 2939 2940 /// Get the size of the given type in char units. 2941 static bool HandleSizeof(EvalInfo &Info, SourceLocation Loc, 2942 QualType Type, CharUnits &Size) { 2943 // sizeof(void), __alignof__(void), sizeof(function) = 1 as a gcc 2944 // extension. 2945 if (Type->isVoidType() || Type->isFunctionType()) { 2946 Size = CharUnits::One(); 2947 return true; 2948 } 2949 2950 if (Type->isDependentType()) { 2951 Info.FFDiag(Loc); 2952 return false; 2953 } 2954 2955 if (!Type->isConstantSizeType()) { 2956 // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2. 2957 // FIXME: Better diagnostic. 2958 Info.FFDiag(Loc); 2959 return false; 2960 } 2961 2962 Size = Info.Ctx.getTypeSizeInChars(Type); 2963 return true; 2964 } 2965 2966 /// Update a pointer value to model pointer arithmetic. 2967 /// \param Info - Information about the ongoing evaluation. 2968 /// \param E - The expression being evaluated, for diagnostic purposes. 2969 /// \param LVal - The pointer value to be updated. 2970 /// \param EltTy - The pointee type represented by LVal. 2971 /// \param Adjustment - The adjustment, in objects of type EltTy, to add. 2972 static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E, 2973 LValue &LVal, QualType EltTy, 2974 APSInt Adjustment) { 2975 CharUnits SizeOfPointee; 2976 if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfPointee)) 2977 return false; 2978 2979 LVal.adjustOffsetAndIndex(Info, E, Adjustment, SizeOfPointee); 2980 return true; 2981 } 2982 2983 static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E, 2984 LValue &LVal, QualType EltTy, 2985 int64_t Adjustment) { 2986 return HandleLValueArrayAdjustment(Info, E, LVal, EltTy, 2987 APSInt::get(Adjustment)); 2988 } 2989 2990 /// Update an lvalue to refer to a component of a complex number. 2991 /// \param Info - Information about the ongoing evaluation. 2992 /// \param LVal - The lvalue to be updated. 2993 /// \param EltTy - The complex number's component type. 2994 /// \param Imag - False for the real component, true for the imaginary. 2995 static bool HandleLValueComplexElement(EvalInfo &Info, const Expr *E, 2996 LValue &LVal, QualType EltTy, 2997 bool Imag) { 2998 if (Imag) { 2999 CharUnits SizeOfComponent; 3000 if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfComponent)) 3001 return false; 3002 LVal.Offset += SizeOfComponent; 3003 } 3004 LVal.addComplex(Info, E, EltTy, Imag); 3005 return true; 3006 } 3007 3008 /// Try to evaluate the initializer for a variable declaration. 3009 /// 3010 /// \param Info Information about the ongoing evaluation. 3011 /// \param E An expression to be used when printing diagnostics. 3012 /// \param VD The variable whose initializer should be obtained. 3013 /// \param Frame The frame in which the variable was created. Must be null 3014 /// if this variable is not local to the evaluation. 3015 /// \param Result Filled in with a pointer to the value of the variable. 3016 static bool evaluateVarDeclInit(EvalInfo &Info, const Expr *E, 3017 const VarDecl *VD, CallStackFrame *Frame, 3018 APValue *&Result, const LValue *LVal) { 3019 3020 // If this is a parameter to an active constexpr function call, perform 3021 // argument substitution. 3022 if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(VD)) { 3023 // Assume arguments of a potential constant expression are unknown 3024 // constant expressions. 3025 if (Info.checkingPotentialConstantExpression()) 3026 return false; 3027 if (!Frame || !Frame->Arguments) { 3028 Info.FFDiag(E, diag::note_constexpr_function_param_value_unknown) << VD; 3029 return false; 3030 } 3031 Result = &Frame->Arguments[PVD->getFunctionScopeIndex()]; 3032 return true; 3033 } 3034 3035 // If this is a local variable, dig out its value. 3036 if (Frame) { 3037 Result = LVal ? Frame->getTemporary(VD, LVal->getLValueVersion()) 3038 : Frame->getCurrentTemporary(VD); 3039 if (!Result) { 3040 // Assume variables referenced within a lambda's call operator that were 3041 // not declared within the call operator are captures and during checking 3042 // of a potential constant expression, assume they are unknown constant 3043 // expressions. 3044 assert(isLambdaCallOperator(Frame->Callee) && 3045 (VD->getDeclContext() != Frame->Callee || VD->isInitCapture()) && 3046 "missing value for local variable"); 3047 if (Info.checkingPotentialConstantExpression()) 3048 return false; 3049 // FIXME: implement capture evaluation during constant expr evaluation. 3050 Info.FFDiag(E->getBeginLoc(), 3051 diag::note_unimplemented_constexpr_lambda_feature_ast) 3052 << "captures not currently allowed"; 3053 return false; 3054 } 3055 return true; 3056 } 3057 3058 // Dig out the initializer, and use the declaration which it's attached to. 3059 // FIXME: We should eventually check whether the variable has a reachable 3060 // initializing declaration. 3061 const Expr *Init = VD->getAnyInitializer(VD); 3062 if (!Init) { 3063 // Don't diagnose during potential constant expression checking; an 3064 // initializer might be added later. 3065 if (!Info.checkingPotentialConstantExpression()) { 3066 Info.FFDiag(E, diag::note_constexpr_var_init_unknown, 1) 3067 << VD; 3068 Info.Note(VD->getLocation(), diag::note_declared_at); 3069 } 3070 return false; 3071 } 3072 3073 if (Init->isValueDependent()) { 3074 // The DeclRefExpr is not value-dependent, but the variable it refers to 3075 // has a value-dependent initializer. This should only happen in 3076 // constant-folding cases, where the variable is not actually of a suitable 3077 // type for use in a constant expression (otherwise the DeclRefExpr would 3078 // have been value-dependent too), so diagnose that. 3079 assert(!VD->mightBeUsableInConstantExpressions(Info.Ctx)); 3080 if (!Info.checkingPotentialConstantExpression()) { 3081 Info.FFDiag(E, Info.getLangOpts().CPlusPlus11 3082 ? diag::note_constexpr_ltor_non_constexpr 3083 : diag::note_constexpr_ltor_non_integral, 1) 3084 << VD << VD->getType(); 3085 Info.Note(VD->getLocation(), diag::note_declared_at); 3086 } 3087 return false; 3088 } 3089 3090 // If we're currently evaluating the initializer of this declaration, use that 3091 // in-flight value. 3092 if (Info.EvaluatingDecl.dyn_cast<const ValueDecl*>() == VD) { 3093 Result = Info.EvaluatingDeclValue; 3094 return true; 3095 } 3096 3097 // Check that we can fold the initializer. In C++, we will have already done 3098 // this in the cases where it matters for conformance. 3099 SmallVector<PartialDiagnosticAt, 8> Notes; 3100 if (!VD->evaluateValue(Notes)) { 3101 Info.FFDiag(E, diag::note_constexpr_var_init_non_constant, 3102 Notes.size() + 1) << VD; 3103 Info.Note(VD->getLocation(), diag::note_declared_at); 3104 Info.addNotes(Notes); 3105 return false; 3106 } 3107 3108 // Check that the variable is actually usable in constant expressions. 3109 if (!VD->checkInitIsICE()) { 3110 Info.CCEDiag(E, diag::note_constexpr_var_init_non_constant, 3111 Notes.size() + 1) << VD; 3112 Info.Note(VD->getLocation(), diag::note_declared_at); 3113 Info.addNotes(Notes); 3114 } 3115 3116 // Never use the initializer of a weak variable, not even for constant 3117 // folding. We can't be sure that this is the definition that will be used. 3118 if (VD->isWeak()) { 3119 Info.FFDiag(E, diag::note_constexpr_var_init_weak) << VD; 3120 Info.Note(VD->getLocation(), diag::note_declared_at); 3121 return false; 3122 } 3123 3124 Result = VD->getEvaluatedValue(); 3125 return true; 3126 } 3127 3128 static bool IsConstNonVolatile(QualType T) { 3129 Qualifiers Quals = T.getQualifiers(); 3130 return Quals.hasConst() && !Quals.hasVolatile(); 3131 } 3132 3133 /// Get the base index of the given base class within an APValue representing 3134 /// the given derived class. 3135 static unsigned getBaseIndex(const CXXRecordDecl *Derived, 3136 const CXXRecordDecl *Base) { 3137 Base = Base->getCanonicalDecl(); 3138 unsigned Index = 0; 3139 for (CXXRecordDecl::base_class_const_iterator I = Derived->bases_begin(), 3140 E = Derived->bases_end(); I != E; ++I, ++Index) { 3141 if (I->getType()->getAsCXXRecordDecl()->getCanonicalDecl() == Base) 3142 return Index; 3143 } 3144 3145 llvm_unreachable("base class missing from derived class's bases list"); 3146 } 3147 3148 /// Extract the value of a character from a string literal. 3149 static APSInt extractStringLiteralCharacter(EvalInfo &Info, const Expr *Lit, 3150 uint64_t Index) { 3151 assert(!isa<SourceLocExpr>(Lit) && 3152 "SourceLocExpr should have already been converted to a StringLiteral"); 3153 3154 // FIXME: Support MakeStringConstant 3155 if (const auto *ObjCEnc = dyn_cast<ObjCEncodeExpr>(Lit)) { 3156 std::string Str; 3157 Info.Ctx.getObjCEncodingForType(ObjCEnc->getEncodedType(), Str); 3158 assert(Index <= Str.size() && "Index too large"); 3159 return APSInt::getUnsigned(Str.c_str()[Index]); 3160 } 3161 3162 if (auto PE = dyn_cast<PredefinedExpr>(Lit)) 3163 Lit = PE->getFunctionName(); 3164 const StringLiteral *S = cast<StringLiteral>(Lit); 3165 const ConstantArrayType *CAT = 3166 Info.Ctx.getAsConstantArrayType(S->getType()); 3167 assert(CAT && "string literal isn't an array"); 3168 QualType CharType = CAT->getElementType(); 3169 assert(CharType->isIntegerType() && "unexpected character type"); 3170 3171 APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(), 3172 CharType->isUnsignedIntegerType()); 3173 if (Index < S->getLength()) 3174 Value = S->getCodeUnit(Index); 3175 return Value; 3176 } 3177 3178 // Expand a string literal into an array of characters. 3179 // 3180 // FIXME: This is inefficient; we should probably introduce something similar 3181 // to the LLVM ConstantDataArray to make this cheaper. 3182 static void expandStringLiteral(EvalInfo &Info, const StringLiteral *S, 3183 APValue &Result, 3184 QualType AllocType = QualType()) { 3185 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType( 3186 AllocType.isNull() ? S->getType() : AllocType); 3187 assert(CAT && "string literal isn't an array"); 3188 QualType CharType = CAT->getElementType(); 3189 assert(CharType->isIntegerType() && "unexpected character type"); 3190 3191 unsigned Elts = CAT->getSize().getZExtValue(); 3192 Result = APValue(APValue::UninitArray(), 3193 std::min(S->getLength(), Elts), Elts); 3194 APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(), 3195 CharType->isUnsignedIntegerType()); 3196 if (Result.hasArrayFiller()) 3197 Result.getArrayFiller() = APValue(Value); 3198 for (unsigned I = 0, N = Result.getArrayInitializedElts(); I != N; ++I) { 3199 Value = S->getCodeUnit(I); 3200 Result.getArrayInitializedElt(I) = APValue(Value); 3201 } 3202 } 3203 3204 // Expand an array so that it has more than Index filled elements. 3205 static void expandArray(APValue &Array, unsigned Index) { 3206 unsigned Size = Array.getArraySize(); 3207 assert(Index < Size); 3208 3209 // Always at least double the number of elements for which we store a value. 3210 unsigned OldElts = Array.getArrayInitializedElts(); 3211 unsigned NewElts = std::max(Index+1, OldElts * 2); 3212 NewElts = std::min(Size, std::max(NewElts, 8u)); 3213 3214 // Copy the data across. 3215 APValue NewValue(APValue::UninitArray(), NewElts, Size); 3216 for (unsigned I = 0; I != OldElts; ++I) 3217 NewValue.getArrayInitializedElt(I).swap(Array.getArrayInitializedElt(I)); 3218 for (unsigned I = OldElts; I != NewElts; ++I) 3219 NewValue.getArrayInitializedElt(I) = Array.getArrayFiller(); 3220 if (NewValue.hasArrayFiller()) 3221 NewValue.getArrayFiller() = Array.getArrayFiller(); 3222 Array.swap(NewValue); 3223 } 3224 3225 /// Determine whether a type would actually be read by an lvalue-to-rvalue 3226 /// conversion. If it's of class type, we may assume that the copy operation 3227 /// is trivial. Note that this is never true for a union type with fields 3228 /// (because the copy always "reads" the active member) and always true for 3229 /// a non-class type. 3230 static bool isReadByLvalueToRvalueConversion(const CXXRecordDecl *RD); 3231 static bool isReadByLvalueToRvalueConversion(QualType T) { 3232 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl(); 3233 return !RD || isReadByLvalueToRvalueConversion(RD); 3234 } 3235 static bool isReadByLvalueToRvalueConversion(const CXXRecordDecl *RD) { 3236 // FIXME: A trivial copy of a union copies the object representation, even if 3237 // the union is empty. 3238 if (RD->isUnion()) 3239 return !RD->field_empty(); 3240 if (RD->isEmpty()) 3241 return false; 3242 3243 for (auto *Field : RD->fields()) 3244 if (!Field->isUnnamedBitfield() && 3245 isReadByLvalueToRvalueConversion(Field->getType())) 3246 return true; 3247 3248 for (auto &BaseSpec : RD->bases()) 3249 if (isReadByLvalueToRvalueConversion(BaseSpec.getType())) 3250 return true; 3251 3252 return false; 3253 } 3254 3255 /// Diagnose an attempt to read from any unreadable field within the specified 3256 /// type, which might be a class type. 3257 static bool diagnoseMutableFields(EvalInfo &Info, const Expr *E, AccessKinds AK, 3258 QualType T) { 3259 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl(); 3260 if (!RD) 3261 return false; 3262 3263 if (!RD->hasMutableFields()) 3264 return false; 3265 3266 for (auto *Field : RD->fields()) { 3267 // If we're actually going to read this field in some way, then it can't 3268 // be mutable. If we're in a union, then assigning to a mutable field 3269 // (even an empty one) can change the active member, so that's not OK. 3270 // FIXME: Add core issue number for the union case. 3271 if (Field->isMutable() && 3272 (RD->isUnion() || isReadByLvalueToRvalueConversion(Field->getType()))) { 3273 Info.FFDiag(E, diag::note_constexpr_access_mutable, 1) << AK << Field; 3274 Info.Note(Field->getLocation(), diag::note_declared_at); 3275 return true; 3276 } 3277 3278 if (diagnoseMutableFields(Info, E, AK, Field->getType())) 3279 return true; 3280 } 3281 3282 for (auto &BaseSpec : RD->bases()) 3283 if (diagnoseMutableFields(Info, E, AK, BaseSpec.getType())) 3284 return true; 3285 3286 // All mutable fields were empty, and thus not actually read. 3287 return false; 3288 } 3289 3290 static bool lifetimeStartedInEvaluation(EvalInfo &Info, 3291 APValue::LValueBase Base, 3292 bool MutableSubobject = false) { 3293 // A temporary we created. 3294 if (Base.getCallIndex()) 3295 return true; 3296 3297 auto *Evaluating = Info.EvaluatingDecl.dyn_cast<const ValueDecl*>(); 3298 if (!Evaluating) 3299 return false; 3300 3301 auto *BaseD = Base.dyn_cast<const ValueDecl*>(); 3302 3303 switch (Info.IsEvaluatingDecl) { 3304 case EvalInfo::EvaluatingDeclKind::None: 3305 return false; 3306 3307 case EvalInfo::EvaluatingDeclKind::Ctor: 3308 // The variable whose initializer we're evaluating. 3309 if (BaseD) 3310 return declaresSameEntity(Evaluating, BaseD); 3311 3312 // A temporary lifetime-extended by the variable whose initializer we're 3313 // evaluating. 3314 if (auto *BaseE = Base.dyn_cast<const Expr *>()) 3315 if (auto *BaseMTE = dyn_cast<MaterializeTemporaryExpr>(BaseE)) 3316 return declaresSameEntity(BaseMTE->getExtendingDecl(), Evaluating); 3317 return false; 3318 3319 case EvalInfo::EvaluatingDeclKind::Dtor: 3320 // C++2a [expr.const]p6: 3321 // [during constant destruction] the lifetime of a and its non-mutable 3322 // subobjects (but not its mutable subobjects) [are] considered to start 3323 // within e. 3324 // 3325 // FIXME: We can meaningfully extend this to cover non-const objects, but 3326 // we will need special handling: we should be able to access only 3327 // subobjects of such objects that are themselves declared const. 3328 if (!BaseD || 3329 !(BaseD->getType().isConstQualified() || 3330 BaseD->getType()->isReferenceType()) || 3331 MutableSubobject) 3332 return false; 3333 return declaresSameEntity(Evaluating, BaseD); 3334 } 3335 3336 llvm_unreachable("unknown evaluating decl kind"); 3337 } 3338 3339 namespace { 3340 /// A handle to a complete object (an object that is not a subobject of 3341 /// another object). 3342 struct CompleteObject { 3343 /// The identity of the object. 3344 APValue::LValueBase Base; 3345 /// The value of the complete object. 3346 APValue *Value; 3347 /// The type of the complete object. 3348 QualType Type; 3349 3350 CompleteObject() : Value(nullptr) {} 3351 CompleteObject(APValue::LValueBase Base, APValue *Value, QualType Type) 3352 : Base(Base), Value(Value), Type(Type) {} 3353 3354 bool mayAccessMutableMembers(EvalInfo &Info, AccessKinds AK) const { 3355 // If this isn't a "real" access (eg, if it's just accessing the type 3356 // info), allow it. We assume the type doesn't change dynamically for 3357 // subobjects of constexpr objects (even though we'd hit UB here if it 3358 // did). FIXME: Is this right? 3359 if (!isAnyAccess(AK)) 3360 return true; 3361 3362 // In C++14 onwards, it is permitted to read a mutable member whose 3363 // lifetime began within the evaluation. 3364 // FIXME: Should we also allow this in C++11? 3365 if (!Info.getLangOpts().CPlusPlus14) 3366 return false; 3367 return lifetimeStartedInEvaluation(Info, Base, /*MutableSubobject*/true); 3368 } 3369 3370 explicit operator bool() const { return !Type.isNull(); } 3371 }; 3372 } // end anonymous namespace 3373 3374 static QualType getSubobjectType(QualType ObjType, QualType SubobjType, 3375 bool IsMutable = false) { 3376 // C++ [basic.type.qualifier]p1: 3377 // - A const object is an object of type const T or a non-mutable subobject 3378 // of a const object. 3379 if (ObjType.isConstQualified() && !IsMutable) 3380 SubobjType.addConst(); 3381 // - A volatile object is an object of type const T or a subobject of a 3382 // volatile object. 3383 if (ObjType.isVolatileQualified()) 3384 SubobjType.addVolatile(); 3385 return SubobjType; 3386 } 3387 3388 /// Find the designated sub-object of an rvalue. 3389 template<typename SubobjectHandler> 3390 typename SubobjectHandler::result_type 3391 findSubobject(EvalInfo &Info, const Expr *E, const CompleteObject &Obj, 3392 const SubobjectDesignator &Sub, SubobjectHandler &handler) { 3393 if (Sub.Invalid) 3394 // A diagnostic will have already been produced. 3395 return handler.failed(); 3396 if (Sub.isOnePastTheEnd() || Sub.isMostDerivedAnUnsizedArray()) { 3397 if (Info.getLangOpts().CPlusPlus11) 3398 Info.FFDiag(E, Sub.isOnePastTheEnd() 3399 ? diag::note_constexpr_access_past_end 3400 : diag::note_constexpr_access_unsized_array) 3401 << handler.AccessKind; 3402 else 3403 Info.FFDiag(E); 3404 return handler.failed(); 3405 } 3406 3407 APValue *O = Obj.Value; 3408 QualType ObjType = Obj.Type; 3409 const FieldDecl *LastField = nullptr; 3410 const FieldDecl *VolatileField = nullptr; 3411 3412 // Walk the designator's path to find the subobject. 3413 for (unsigned I = 0, N = Sub.Entries.size(); /**/; ++I) { 3414 // Reading an indeterminate value is undefined, but assigning over one is OK. 3415 if ((O->isAbsent() && !(handler.AccessKind == AK_Construct && I == N)) || 3416 (O->isIndeterminate() && 3417 !isValidIndeterminateAccess(handler.AccessKind))) { 3418 if (!Info.checkingPotentialConstantExpression()) 3419 Info.FFDiag(E, diag::note_constexpr_access_uninit) 3420 << handler.AccessKind << O->isIndeterminate(); 3421 return handler.failed(); 3422 } 3423 3424 // C++ [class.ctor]p5, C++ [class.dtor]p5: 3425 // const and volatile semantics are not applied on an object under 3426 // {con,de}struction. 3427 if ((ObjType.isConstQualified() || ObjType.isVolatileQualified()) && 3428 ObjType->isRecordType() && 3429 Info.isEvaluatingCtorDtor( 3430 Obj.Base, llvm::makeArrayRef(Sub.Entries.begin(), 3431 Sub.Entries.begin() + I)) != 3432 ConstructionPhase::None) { 3433 ObjType = Info.Ctx.getCanonicalType(ObjType); 3434 ObjType.removeLocalConst(); 3435 ObjType.removeLocalVolatile(); 3436 } 3437 3438 // If this is our last pass, check that the final object type is OK. 3439 if (I == N || (I == N - 1 && ObjType->isAnyComplexType())) { 3440 // Accesses to volatile objects are prohibited. 3441 if (ObjType.isVolatileQualified() && isFormalAccess(handler.AccessKind)) { 3442 if (Info.getLangOpts().CPlusPlus) { 3443 int DiagKind; 3444 SourceLocation Loc; 3445 const NamedDecl *Decl = nullptr; 3446 if (VolatileField) { 3447 DiagKind = 2; 3448 Loc = VolatileField->getLocation(); 3449 Decl = VolatileField; 3450 } else if (auto *VD = Obj.Base.dyn_cast<const ValueDecl*>()) { 3451 DiagKind = 1; 3452 Loc = VD->getLocation(); 3453 Decl = VD; 3454 } else { 3455 DiagKind = 0; 3456 if (auto *E = Obj.Base.dyn_cast<const Expr *>()) 3457 Loc = E->getExprLoc(); 3458 } 3459 Info.FFDiag(E, diag::note_constexpr_access_volatile_obj, 1) 3460 << handler.AccessKind << DiagKind << Decl; 3461 Info.Note(Loc, diag::note_constexpr_volatile_here) << DiagKind; 3462 } else { 3463 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr); 3464 } 3465 return handler.failed(); 3466 } 3467 3468 // If we are reading an object of class type, there may still be more 3469 // things we need to check: if there are any mutable subobjects, we 3470 // cannot perform this read. (This only happens when performing a trivial 3471 // copy or assignment.) 3472 if (ObjType->isRecordType() && 3473 !Obj.mayAccessMutableMembers(Info, handler.AccessKind) && 3474 diagnoseMutableFields(Info, E, handler.AccessKind, ObjType)) 3475 return handler.failed(); 3476 } 3477 3478 if (I == N) { 3479 if (!handler.found(*O, ObjType)) 3480 return false; 3481 3482 // If we modified a bit-field, truncate it to the right width. 3483 if (isModification(handler.AccessKind) && 3484 LastField && LastField->isBitField() && 3485 !truncateBitfieldValue(Info, E, *O, LastField)) 3486 return false; 3487 3488 return true; 3489 } 3490 3491 LastField = nullptr; 3492 if (ObjType->isArrayType()) { 3493 // Next subobject is an array element. 3494 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(ObjType); 3495 assert(CAT && "vla in literal type?"); 3496 uint64_t Index = Sub.Entries[I].getAsArrayIndex(); 3497 if (CAT->getSize().ule(Index)) { 3498 // Note, it should not be possible to form a pointer with a valid 3499 // designator which points more than one past the end of the array. 3500 if (Info.getLangOpts().CPlusPlus11) 3501 Info.FFDiag(E, diag::note_constexpr_access_past_end) 3502 << handler.AccessKind; 3503 else 3504 Info.FFDiag(E); 3505 return handler.failed(); 3506 } 3507 3508 ObjType = CAT->getElementType(); 3509 3510 if (O->getArrayInitializedElts() > Index) 3511 O = &O->getArrayInitializedElt(Index); 3512 else if (!isRead(handler.AccessKind)) { 3513 expandArray(*O, Index); 3514 O = &O->getArrayInitializedElt(Index); 3515 } else 3516 O = &O->getArrayFiller(); 3517 } else if (ObjType->isAnyComplexType()) { 3518 // Next subobject is a complex number. 3519 uint64_t Index = Sub.Entries[I].getAsArrayIndex(); 3520 if (Index > 1) { 3521 if (Info.getLangOpts().CPlusPlus11) 3522 Info.FFDiag(E, diag::note_constexpr_access_past_end) 3523 << handler.AccessKind; 3524 else 3525 Info.FFDiag(E); 3526 return handler.failed(); 3527 } 3528 3529 ObjType = getSubobjectType( 3530 ObjType, ObjType->castAs<ComplexType>()->getElementType()); 3531 3532 assert(I == N - 1 && "extracting subobject of scalar?"); 3533 if (O->isComplexInt()) { 3534 return handler.found(Index ? O->getComplexIntImag() 3535 : O->getComplexIntReal(), ObjType); 3536 } else { 3537 assert(O->isComplexFloat()); 3538 return handler.found(Index ? O->getComplexFloatImag() 3539 : O->getComplexFloatReal(), ObjType); 3540 } 3541 } else if (const FieldDecl *Field = getAsField(Sub.Entries[I])) { 3542 if (Field->isMutable() && 3543 !Obj.mayAccessMutableMembers(Info, handler.AccessKind)) { 3544 Info.FFDiag(E, diag::note_constexpr_access_mutable, 1) 3545 << handler.AccessKind << Field; 3546 Info.Note(Field->getLocation(), diag::note_declared_at); 3547 return handler.failed(); 3548 } 3549 3550 // Next subobject is a class, struct or union field. 3551 RecordDecl *RD = ObjType->castAs<RecordType>()->getDecl(); 3552 if (RD->isUnion()) { 3553 const FieldDecl *UnionField = O->getUnionField(); 3554 if (!UnionField || 3555 UnionField->getCanonicalDecl() != Field->getCanonicalDecl()) { 3556 if (I == N - 1 && handler.AccessKind == AK_Construct) { 3557 // Placement new onto an inactive union member makes it active. 3558 O->setUnion(Field, APValue()); 3559 } else { 3560 // FIXME: If O->getUnionValue() is absent, report that there's no 3561 // active union member rather than reporting the prior active union 3562 // member. We'll need to fix nullptr_t to not use APValue() as its 3563 // representation first. 3564 Info.FFDiag(E, diag::note_constexpr_access_inactive_union_member) 3565 << handler.AccessKind << Field << !UnionField << UnionField; 3566 return handler.failed(); 3567 } 3568 } 3569 O = &O->getUnionValue(); 3570 } else 3571 O = &O->getStructField(Field->getFieldIndex()); 3572 3573 ObjType = getSubobjectType(ObjType, Field->getType(), Field->isMutable()); 3574 LastField = Field; 3575 if (Field->getType().isVolatileQualified()) 3576 VolatileField = Field; 3577 } else { 3578 // Next subobject is a base class. 3579 const CXXRecordDecl *Derived = ObjType->getAsCXXRecordDecl(); 3580 const CXXRecordDecl *Base = getAsBaseClass(Sub.Entries[I]); 3581 O = &O->getStructBase(getBaseIndex(Derived, Base)); 3582 3583 ObjType = getSubobjectType(ObjType, Info.Ctx.getRecordType(Base)); 3584 } 3585 } 3586 } 3587 3588 namespace { 3589 struct ExtractSubobjectHandler { 3590 EvalInfo &Info; 3591 const Expr *E; 3592 APValue &Result; 3593 const AccessKinds AccessKind; 3594 3595 typedef bool result_type; 3596 bool failed() { return false; } 3597 bool found(APValue &Subobj, QualType SubobjType) { 3598 Result = Subobj; 3599 if (AccessKind == AK_ReadObjectRepresentation) 3600 return true; 3601 return CheckFullyInitialized(Info, E->getExprLoc(), SubobjType, Result); 3602 } 3603 bool found(APSInt &Value, QualType SubobjType) { 3604 Result = APValue(Value); 3605 return true; 3606 } 3607 bool found(APFloat &Value, QualType SubobjType) { 3608 Result = APValue(Value); 3609 return true; 3610 } 3611 }; 3612 } // end anonymous namespace 3613 3614 /// Extract the designated sub-object of an rvalue. 3615 static bool extractSubobject(EvalInfo &Info, const Expr *E, 3616 const CompleteObject &Obj, 3617 const SubobjectDesignator &Sub, APValue &Result, 3618 AccessKinds AK = AK_Read) { 3619 assert(AK == AK_Read || AK == AK_ReadObjectRepresentation); 3620 ExtractSubobjectHandler Handler = {Info, E, Result, AK}; 3621 return findSubobject(Info, E, Obj, Sub, Handler); 3622 } 3623 3624 namespace { 3625 struct ModifySubobjectHandler { 3626 EvalInfo &Info; 3627 APValue &NewVal; 3628 const Expr *E; 3629 3630 typedef bool result_type; 3631 static const AccessKinds AccessKind = AK_Assign; 3632 3633 bool checkConst(QualType QT) { 3634 // Assigning to a const object has undefined behavior. 3635 if (QT.isConstQualified()) { 3636 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT; 3637 return false; 3638 } 3639 return true; 3640 } 3641 3642 bool failed() { return false; } 3643 bool found(APValue &Subobj, QualType SubobjType) { 3644 if (!checkConst(SubobjType)) 3645 return false; 3646 // We've been given ownership of NewVal, so just swap it in. 3647 Subobj.swap(NewVal); 3648 return true; 3649 } 3650 bool found(APSInt &Value, QualType SubobjType) { 3651 if (!checkConst(SubobjType)) 3652 return false; 3653 if (!NewVal.isInt()) { 3654 // Maybe trying to write a cast pointer value into a complex? 3655 Info.FFDiag(E); 3656 return false; 3657 } 3658 Value = NewVal.getInt(); 3659 return true; 3660 } 3661 bool found(APFloat &Value, QualType SubobjType) { 3662 if (!checkConst(SubobjType)) 3663 return false; 3664 Value = NewVal.getFloat(); 3665 return true; 3666 } 3667 }; 3668 } // end anonymous namespace 3669 3670 const AccessKinds ModifySubobjectHandler::AccessKind; 3671 3672 /// Update the designated sub-object of an rvalue to the given value. 3673 static bool modifySubobject(EvalInfo &Info, const Expr *E, 3674 const CompleteObject &Obj, 3675 const SubobjectDesignator &Sub, 3676 APValue &NewVal) { 3677 ModifySubobjectHandler Handler = { Info, NewVal, E }; 3678 return findSubobject(Info, E, Obj, Sub, Handler); 3679 } 3680 3681 /// Find the position where two subobject designators diverge, or equivalently 3682 /// the length of the common initial subsequence. 3683 static unsigned FindDesignatorMismatch(QualType ObjType, 3684 const SubobjectDesignator &A, 3685 const SubobjectDesignator &B, 3686 bool &WasArrayIndex) { 3687 unsigned I = 0, N = std::min(A.Entries.size(), B.Entries.size()); 3688 for (/**/; I != N; ++I) { 3689 if (!ObjType.isNull() && 3690 (ObjType->isArrayType() || ObjType->isAnyComplexType())) { 3691 // Next subobject is an array element. 3692 if (A.Entries[I].getAsArrayIndex() != B.Entries[I].getAsArrayIndex()) { 3693 WasArrayIndex = true; 3694 return I; 3695 } 3696 if (ObjType->isAnyComplexType()) 3697 ObjType = ObjType->castAs<ComplexType>()->getElementType(); 3698 else 3699 ObjType = ObjType->castAsArrayTypeUnsafe()->getElementType(); 3700 } else { 3701 if (A.Entries[I].getAsBaseOrMember() != 3702 B.Entries[I].getAsBaseOrMember()) { 3703 WasArrayIndex = false; 3704 return I; 3705 } 3706 if (const FieldDecl *FD = getAsField(A.Entries[I])) 3707 // Next subobject is a field. 3708 ObjType = FD->getType(); 3709 else 3710 // Next subobject is a base class. 3711 ObjType = QualType(); 3712 } 3713 } 3714 WasArrayIndex = false; 3715 return I; 3716 } 3717 3718 /// Determine whether the given subobject designators refer to elements of the 3719 /// same array object. 3720 static bool AreElementsOfSameArray(QualType ObjType, 3721 const SubobjectDesignator &A, 3722 const SubobjectDesignator &B) { 3723 if (A.Entries.size() != B.Entries.size()) 3724 return false; 3725 3726 bool IsArray = A.MostDerivedIsArrayElement; 3727 if (IsArray && A.MostDerivedPathLength != A.Entries.size()) 3728 // A is a subobject of the array element. 3729 return false; 3730 3731 // If A (and B) designates an array element, the last entry will be the array 3732 // index. That doesn't have to match. Otherwise, we're in the 'implicit array 3733 // of length 1' case, and the entire path must match. 3734 bool WasArrayIndex; 3735 unsigned CommonLength = FindDesignatorMismatch(ObjType, A, B, WasArrayIndex); 3736 return CommonLength >= A.Entries.size() - IsArray; 3737 } 3738 3739 /// Find the complete object to which an LValue refers. 3740 static CompleteObject findCompleteObject(EvalInfo &Info, const Expr *E, 3741 AccessKinds AK, const LValue &LVal, 3742 QualType LValType) { 3743 if (LVal.InvalidBase) { 3744 Info.FFDiag(E); 3745 return CompleteObject(); 3746 } 3747 3748 if (!LVal.Base) { 3749 Info.FFDiag(E, diag::note_constexpr_access_null) << AK; 3750 return CompleteObject(); 3751 } 3752 3753 CallStackFrame *Frame = nullptr; 3754 unsigned Depth = 0; 3755 if (LVal.getLValueCallIndex()) { 3756 std::tie(Frame, Depth) = 3757 Info.getCallFrameAndDepth(LVal.getLValueCallIndex()); 3758 if (!Frame) { 3759 Info.FFDiag(E, diag::note_constexpr_lifetime_ended, 1) 3760 << AK << LVal.Base.is<const ValueDecl*>(); 3761 NoteLValueLocation(Info, LVal.Base); 3762 return CompleteObject(); 3763 } 3764 } 3765 3766 bool IsAccess = isAnyAccess(AK); 3767 3768 // C++11 DR1311: An lvalue-to-rvalue conversion on a volatile-qualified type 3769 // is not a constant expression (even if the object is non-volatile). We also 3770 // apply this rule to C++98, in order to conform to the expected 'volatile' 3771 // semantics. 3772 if (isFormalAccess(AK) && LValType.isVolatileQualified()) { 3773 if (Info.getLangOpts().CPlusPlus) 3774 Info.FFDiag(E, diag::note_constexpr_access_volatile_type) 3775 << AK << LValType; 3776 else 3777 Info.FFDiag(E); 3778 return CompleteObject(); 3779 } 3780 3781 // Compute value storage location and type of base object. 3782 APValue *BaseVal = nullptr; 3783 QualType BaseType = getType(LVal.Base); 3784 3785 if (const ConstantExpr *CE = 3786 dyn_cast_or_null<ConstantExpr>(LVal.Base.dyn_cast<const Expr *>())) { 3787 /// Nested immediate invocation have been previously removed so if we found 3788 /// a ConstantExpr it can only be the EvaluatingDecl. 3789 assert(CE->isImmediateInvocation() && CE == Info.EvaluatingDecl); 3790 (void)CE; 3791 BaseVal = Info.EvaluatingDeclValue; 3792 } else if (const ValueDecl *D = LVal.Base.dyn_cast<const ValueDecl *>()) { 3793 // Allow reading from a GUID declaration. 3794 if (auto *GD = dyn_cast<MSGuidDecl>(D)) { 3795 if (isModification(AK)) { 3796 // All the remaining cases do not permit modification of the object. 3797 Info.FFDiag(E, diag::note_constexpr_modify_global); 3798 return CompleteObject(); 3799 } 3800 APValue &V = GD->getAsAPValue(); 3801 if (V.isAbsent()) { 3802 Info.FFDiag(E, diag::note_constexpr_unsupported_layout) 3803 << GD->getType(); 3804 return CompleteObject(); 3805 } 3806 return CompleteObject(LVal.Base, &V, GD->getType()); 3807 } 3808 3809 // In C++98, const, non-volatile integers initialized with ICEs are ICEs. 3810 // In C++11, constexpr, non-volatile variables initialized with constant 3811 // expressions are constant expressions too. Inside constexpr functions, 3812 // parameters are constant expressions even if they're non-const. 3813 // In C++1y, objects local to a constant expression (those with a Frame) are 3814 // both readable and writable inside constant expressions. 3815 // In C, such things can also be folded, although they are not ICEs. 3816 const VarDecl *VD = dyn_cast<VarDecl>(D); 3817 if (VD) { 3818 if (const VarDecl *VDef = VD->getDefinition(Info.Ctx)) 3819 VD = VDef; 3820 } 3821 if (!VD || VD->isInvalidDecl()) { 3822 Info.FFDiag(E); 3823 return CompleteObject(); 3824 } 3825 3826 // In OpenCL if a variable is in constant address space it is a const value. 3827 bool IsConstant = BaseType.isConstQualified() || 3828 (Info.getLangOpts().OpenCL && 3829 BaseType.getAddressSpace() == LangAS::opencl_constant); 3830 3831 // Unless we're looking at a local variable or argument in a constexpr call, 3832 // the variable we're reading must be const. 3833 if (!Frame) { 3834 if (Info.getLangOpts().CPlusPlus14 && 3835 lifetimeStartedInEvaluation(Info, LVal.Base)) { 3836 // OK, we can read and modify an object if we're in the process of 3837 // evaluating its initializer, because its lifetime began in this 3838 // evaluation. 3839 } else if (isModification(AK)) { 3840 // All the remaining cases do not permit modification of the object. 3841 Info.FFDiag(E, diag::note_constexpr_modify_global); 3842 return CompleteObject(); 3843 } else if (VD->isConstexpr()) { 3844 // OK, we can read this variable. 3845 } else if (BaseType->isIntegralOrEnumerationType()) { 3846 // In OpenCL if a variable is in constant address space it is a const 3847 // value. 3848 if (!IsConstant) { 3849 if (!IsAccess) 3850 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType); 3851 if (Info.getLangOpts().CPlusPlus) { 3852 Info.FFDiag(E, diag::note_constexpr_ltor_non_const_int, 1) << VD; 3853 Info.Note(VD->getLocation(), diag::note_declared_at); 3854 } else { 3855 Info.FFDiag(E); 3856 } 3857 return CompleteObject(); 3858 } 3859 } else if (!IsAccess) { 3860 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType); 3861 } else if (IsConstant && Info.checkingPotentialConstantExpression() && 3862 BaseType->isLiteralType(Info.Ctx) && !VD->hasDefinition()) { 3863 // This variable might end up being constexpr. Don't diagnose it yet. 3864 } else if (IsConstant) { 3865 // Keep evaluating to see what we can do. In particular, we support 3866 // folding of const floating-point types, in order to make static const 3867 // data members of such types (supported as an extension) more useful. 3868 if (Info.getLangOpts().CPlusPlus) { 3869 Info.CCEDiag(E, Info.getLangOpts().CPlusPlus11 3870 ? diag::note_constexpr_ltor_non_constexpr 3871 : diag::note_constexpr_ltor_non_integral, 1) 3872 << VD << BaseType; 3873 Info.Note(VD->getLocation(), diag::note_declared_at); 3874 } else { 3875 Info.CCEDiag(E); 3876 } 3877 } else { 3878 // Never allow reading a non-const value. 3879 if (Info.getLangOpts().CPlusPlus) { 3880 Info.FFDiag(E, Info.getLangOpts().CPlusPlus11 3881 ? diag::note_constexpr_ltor_non_constexpr 3882 : diag::note_constexpr_ltor_non_integral, 1) 3883 << VD << BaseType; 3884 Info.Note(VD->getLocation(), diag::note_declared_at); 3885 } else { 3886 Info.FFDiag(E); 3887 } 3888 return CompleteObject(); 3889 } 3890 } 3891 3892 if (!evaluateVarDeclInit(Info, E, VD, Frame, BaseVal, &LVal)) 3893 return CompleteObject(); 3894 } else if (DynamicAllocLValue DA = LVal.Base.dyn_cast<DynamicAllocLValue>()) { 3895 Optional<DynAlloc*> Alloc = Info.lookupDynamicAlloc(DA); 3896 if (!Alloc) { 3897 Info.FFDiag(E, diag::note_constexpr_access_deleted_object) << AK; 3898 return CompleteObject(); 3899 } 3900 return CompleteObject(LVal.Base, &(*Alloc)->Value, 3901 LVal.Base.getDynamicAllocType()); 3902 } else { 3903 const Expr *Base = LVal.Base.dyn_cast<const Expr*>(); 3904 3905 if (!Frame) { 3906 if (const MaterializeTemporaryExpr *MTE = 3907 dyn_cast_or_null<MaterializeTemporaryExpr>(Base)) { 3908 assert(MTE->getStorageDuration() == SD_Static && 3909 "should have a frame for a non-global materialized temporary"); 3910 3911 // Per C++1y [expr.const]p2: 3912 // an lvalue-to-rvalue conversion [is not allowed unless it applies to] 3913 // - a [...] glvalue of integral or enumeration type that refers to 3914 // a non-volatile const object [...] 3915 // [...] 3916 // - a [...] glvalue of literal type that refers to a non-volatile 3917 // object whose lifetime began within the evaluation of e. 3918 // 3919 // C++11 misses the 'began within the evaluation of e' check and 3920 // instead allows all temporaries, including things like: 3921 // int &&r = 1; 3922 // int x = ++r; 3923 // constexpr int k = r; 3924 // Therefore we use the C++14 rules in C++11 too. 3925 // 3926 // Note that temporaries whose lifetimes began while evaluating a 3927 // variable's constructor are not usable while evaluating the 3928 // corresponding destructor, not even if they're of const-qualified 3929 // types. 3930 if (!(BaseType.isConstQualified() && 3931 BaseType->isIntegralOrEnumerationType()) && 3932 !lifetimeStartedInEvaluation(Info, LVal.Base)) { 3933 if (!IsAccess) 3934 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType); 3935 Info.FFDiag(E, diag::note_constexpr_access_static_temporary, 1) << AK; 3936 Info.Note(MTE->getExprLoc(), diag::note_constexpr_temporary_here); 3937 return CompleteObject(); 3938 } 3939 3940 BaseVal = MTE->getOrCreateValue(false); 3941 assert(BaseVal && "got reference to unevaluated temporary"); 3942 } else { 3943 if (!IsAccess) 3944 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType); 3945 APValue Val; 3946 LVal.moveInto(Val); 3947 Info.FFDiag(E, diag::note_constexpr_access_unreadable_object) 3948 << AK 3949 << Val.getAsString(Info.Ctx, 3950 Info.Ctx.getLValueReferenceType(LValType)); 3951 NoteLValueLocation(Info, LVal.Base); 3952 return CompleteObject(); 3953 } 3954 } else { 3955 BaseVal = Frame->getTemporary(Base, LVal.Base.getVersion()); 3956 assert(BaseVal && "missing value for temporary"); 3957 } 3958 } 3959 3960 // In C++14, we can't safely access any mutable state when we might be 3961 // evaluating after an unmodeled side effect. 3962 // 3963 // FIXME: Not all local state is mutable. Allow local constant subobjects 3964 // to be read here (but take care with 'mutable' fields). 3965 if ((Frame && Info.getLangOpts().CPlusPlus14 && 3966 Info.EvalStatus.HasSideEffects) || 3967 (isModification(AK) && Depth < Info.SpeculativeEvaluationDepth)) 3968 return CompleteObject(); 3969 3970 return CompleteObject(LVal.getLValueBase(), BaseVal, BaseType); 3971 } 3972 3973 /// Perform an lvalue-to-rvalue conversion on the given glvalue. This 3974 /// can also be used for 'lvalue-to-lvalue' conversions for looking up the 3975 /// glvalue referred to by an entity of reference type. 3976 /// 3977 /// \param Info - Information about the ongoing evaluation. 3978 /// \param Conv - The expression for which we are performing the conversion. 3979 /// Used for diagnostics. 3980 /// \param Type - The type of the glvalue (before stripping cv-qualifiers in the 3981 /// case of a non-class type). 3982 /// \param LVal - The glvalue on which we are attempting to perform this action. 3983 /// \param RVal - The produced value will be placed here. 3984 /// \param WantObjectRepresentation - If true, we're looking for the object 3985 /// representation rather than the value, and in particular, 3986 /// there is no requirement that the result be fully initialized. 3987 static bool 3988 handleLValueToRValueConversion(EvalInfo &Info, const Expr *Conv, QualType Type, 3989 const LValue &LVal, APValue &RVal, 3990 bool WantObjectRepresentation = false) { 3991 if (LVal.Designator.Invalid) 3992 return false; 3993 3994 // Check for special cases where there is no existing APValue to look at. 3995 const Expr *Base = LVal.Base.dyn_cast<const Expr*>(); 3996 3997 AccessKinds AK = 3998 WantObjectRepresentation ? AK_ReadObjectRepresentation : AK_Read; 3999 4000 if (Base && !LVal.getLValueCallIndex() && !Type.isVolatileQualified()) { 4001 if (const CompoundLiteralExpr *CLE = dyn_cast<CompoundLiteralExpr>(Base)) { 4002 // In C99, a CompoundLiteralExpr is an lvalue, and we defer evaluating the 4003 // initializer until now for such expressions. Such an expression can't be 4004 // an ICE in C, so this only matters for fold. 4005 if (Type.isVolatileQualified()) { 4006 Info.FFDiag(Conv); 4007 return false; 4008 } 4009 APValue Lit; 4010 if (!Evaluate(Lit, Info, CLE->getInitializer())) 4011 return false; 4012 CompleteObject LitObj(LVal.Base, &Lit, Base->getType()); 4013 return extractSubobject(Info, Conv, LitObj, LVal.Designator, RVal, AK); 4014 } else if (isa<StringLiteral>(Base) || isa<PredefinedExpr>(Base)) { 4015 // Special-case character extraction so we don't have to construct an 4016 // APValue for the whole string. 4017 assert(LVal.Designator.Entries.size() <= 1 && 4018 "Can only read characters from string literals"); 4019 if (LVal.Designator.Entries.empty()) { 4020 // Fail for now for LValue to RValue conversion of an array. 4021 // (This shouldn't show up in C/C++, but it could be triggered by a 4022 // weird EvaluateAsRValue call from a tool.) 4023 Info.FFDiag(Conv); 4024 return false; 4025 } 4026 if (LVal.Designator.isOnePastTheEnd()) { 4027 if (Info.getLangOpts().CPlusPlus11) 4028 Info.FFDiag(Conv, diag::note_constexpr_access_past_end) << AK; 4029 else 4030 Info.FFDiag(Conv); 4031 return false; 4032 } 4033 uint64_t CharIndex = LVal.Designator.Entries[0].getAsArrayIndex(); 4034 RVal = APValue(extractStringLiteralCharacter(Info, Base, CharIndex)); 4035 return true; 4036 } 4037 } 4038 4039 CompleteObject Obj = findCompleteObject(Info, Conv, AK, LVal, Type); 4040 return Obj && extractSubobject(Info, Conv, Obj, LVal.Designator, RVal, AK); 4041 } 4042 4043 /// Perform an assignment of Val to LVal. Takes ownership of Val. 4044 static bool handleAssignment(EvalInfo &Info, const Expr *E, const LValue &LVal, 4045 QualType LValType, APValue &Val) { 4046 if (LVal.Designator.Invalid) 4047 return false; 4048 4049 if (!Info.getLangOpts().CPlusPlus14) { 4050 Info.FFDiag(E); 4051 return false; 4052 } 4053 4054 CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType); 4055 return Obj && modifySubobject(Info, E, Obj, LVal.Designator, Val); 4056 } 4057 4058 namespace { 4059 struct CompoundAssignSubobjectHandler { 4060 EvalInfo &Info; 4061 const Expr *E; 4062 QualType PromotedLHSType; 4063 BinaryOperatorKind Opcode; 4064 const APValue &RHS; 4065 4066 static const AccessKinds AccessKind = AK_Assign; 4067 4068 typedef bool result_type; 4069 4070 bool checkConst(QualType QT) { 4071 // Assigning to a const object has undefined behavior. 4072 if (QT.isConstQualified()) { 4073 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT; 4074 return false; 4075 } 4076 return true; 4077 } 4078 4079 bool failed() { return false; } 4080 bool found(APValue &Subobj, QualType SubobjType) { 4081 switch (Subobj.getKind()) { 4082 case APValue::Int: 4083 return found(Subobj.getInt(), SubobjType); 4084 case APValue::Float: 4085 return found(Subobj.getFloat(), SubobjType); 4086 case APValue::ComplexInt: 4087 case APValue::ComplexFloat: 4088 // FIXME: Implement complex compound assignment. 4089 Info.FFDiag(E); 4090 return false; 4091 case APValue::LValue: 4092 return foundPointer(Subobj, SubobjType); 4093 case APValue::Vector: 4094 return foundVector(Subobj, SubobjType); 4095 default: 4096 // FIXME: can this happen? 4097 Info.FFDiag(E); 4098 return false; 4099 } 4100 } 4101 4102 bool foundVector(APValue &Value, QualType SubobjType) { 4103 if (!checkConst(SubobjType)) 4104 return false; 4105 4106 if (!SubobjType->isVectorType()) { 4107 Info.FFDiag(E); 4108 return false; 4109 } 4110 return handleVectorVectorBinOp(Info, E, Opcode, Value, RHS); 4111 } 4112 4113 bool found(APSInt &Value, QualType SubobjType) { 4114 if (!checkConst(SubobjType)) 4115 return false; 4116 4117 if (!SubobjType->isIntegerType()) { 4118 // We don't support compound assignment on integer-cast-to-pointer 4119 // values. 4120 Info.FFDiag(E); 4121 return false; 4122 } 4123 4124 if (RHS.isInt()) { 4125 APSInt LHS = 4126 HandleIntToIntCast(Info, E, PromotedLHSType, SubobjType, Value); 4127 if (!handleIntIntBinOp(Info, E, LHS, Opcode, RHS.getInt(), LHS)) 4128 return false; 4129 Value = HandleIntToIntCast(Info, E, SubobjType, PromotedLHSType, LHS); 4130 return true; 4131 } else if (RHS.isFloat()) { 4132 APFloat FValue(0.0); 4133 return HandleIntToFloatCast(Info, E, SubobjType, Value, PromotedLHSType, 4134 FValue) && 4135 handleFloatFloatBinOp(Info, E, FValue, Opcode, RHS.getFloat()) && 4136 HandleFloatToIntCast(Info, E, PromotedLHSType, FValue, SubobjType, 4137 Value); 4138 } 4139 4140 Info.FFDiag(E); 4141 return false; 4142 } 4143 bool found(APFloat &Value, QualType SubobjType) { 4144 return checkConst(SubobjType) && 4145 HandleFloatToFloatCast(Info, E, SubobjType, PromotedLHSType, 4146 Value) && 4147 handleFloatFloatBinOp(Info, E, Value, Opcode, RHS.getFloat()) && 4148 HandleFloatToFloatCast(Info, E, PromotedLHSType, SubobjType, Value); 4149 } 4150 bool foundPointer(APValue &Subobj, QualType SubobjType) { 4151 if (!checkConst(SubobjType)) 4152 return false; 4153 4154 QualType PointeeType; 4155 if (const PointerType *PT = SubobjType->getAs<PointerType>()) 4156 PointeeType = PT->getPointeeType(); 4157 4158 if (PointeeType.isNull() || !RHS.isInt() || 4159 (Opcode != BO_Add && Opcode != BO_Sub)) { 4160 Info.FFDiag(E); 4161 return false; 4162 } 4163 4164 APSInt Offset = RHS.getInt(); 4165 if (Opcode == BO_Sub) 4166 negateAsSigned(Offset); 4167 4168 LValue LVal; 4169 LVal.setFrom(Info.Ctx, Subobj); 4170 if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType, Offset)) 4171 return false; 4172 LVal.moveInto(Subobj); 4173 return true; 4174 } 4175 }; 4176 } // end anonymous namespace 4177 4178 const AccessKinds CompoundAssignSubobjectHandler::AccessKind; 4179 4180 /// Perform a compound assignment of LVal <op>= RVal. 4181 static bool handleCompoundAssignment( 4182 EvalInfo &Info, const Expr *E, 4183 const LValue &LVal, QualType LValType, QualType PromotedLValType, 4184 BinaryOperatorKind Opcode, const APValue &RVal) { 4185 if (LVal.Designator.Invalid) 4186 return false; 4187 4188 if (!Info.getLangOpts().CPlusPlus14) { 4189 Info.FFDiag(E); 4190 return false; 4191 } 4192 4193 CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType); 4194 CompoundAssignSubobjectHandler Handler = { Info, E, PromotedLValType, Opcode, 4195 RVal }; 4196 return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler); 4197 } 4198 4199 namespace { 4200 struct IncDecSubobjectHandler { 4201 EvalInfo &Info; 4202 const UnaryOperator *E; 4203 AccessKinds AccessKind; 4204 APValue *Old; 4205 4206 typedef bool result_type; 4207 4208 bool checkConst(QualType QT) { 4209 // Assigning to a const object has undefined behavior. 4210 if (QT.isConstQualified()) { 4211 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT; 4212 return false; 4213 } 4214 return true; 4215 } 4216 4217 bool failed() { return false; } 4218 bool found(APValue &Subobj, QualType SubobjType) { 4219 // Stash the old value. Also clear Old, so we don't clobber it later 4220 // if we're post-incrementing a complex. 4221 if (Old) { 4222 *Old = Subobj; 4223 Old = nullptr; 4224 } 4225 4226 switch (Subobj.getKind()) { 4227 case APValue::Int: 4228 return found(Subobj.getInt(), SubobjType); 4229 case APValue::Float: 4230 return found(Subobj.getFloat(), SubobjType); 4231 case APValue::ComplexInt: 4232 return found(Subobj.getComplexIntReal(), 4233 SubobjType->castAs<ComplexType>()->getElementType() 4234 .withCVRQualifiers(SubobjType.getCVRQualifiers())); 4235 case APValue::ComplexFloat: 4236 return found(Subobj.getComplexFloatReal(), 4237 SubobjType->castAs<ComplexType>()->getElementType() 4238 .withCVRQualifiers(SubobjType.getCVRQualifiers())); 4239 case APValue::LValue: 4240 return foundPointer(Subobj, SubobjType); 4241 default: 4242 // FIXME: can this happen? 4243 Info.FFDiag(E); 4244 return false; 4245 } 4246 } 4247 bool found(APSInt &Value, QualType SubobjType) { 4248 if (!checkConst(SubobjType)) 4249 return false; 4250 4251 if (!SubobjType->isIntegerType()) { 4252 // We don't support increment / decrement on integer-cast-to-pointer 4253 // values. 4254 Info.FFDiag(E); 4255 return false; 4256 } 4257 4258 if (Old) *Old = APValue(Value); 4259 4260 // bool arithmetic promotes to int, and the conversion back to bool 4261 // doesn't reduce mod 2^n, so special-case it. 4262 if (SubobjType->isBooleanType()) { 4263 if (AccessKind == AK_Increment) 4264 Value = 1; 4265 else 4266 Value = !Value; 4267 return true; 4268 } 4269 4270 bool WasNegative = Value.isNegative(); 4271 if (AccessKind == AK_Increment) { 4272 ++Value; 4273 4274 if (!WasNegative && Value.isNegative() && E->canOverflow()) { 4275 APSInt ActualValue(Value, /*IsUnsigned*/true); 4276 return HandleOverflow(Info, E, ActualValue, SubobjType); 4277 } 4278 } else { 4279 --Value; 4280 4281 if (WasNegative && !Value.isNegative() && E->canOverflow()) { 4282 unsigned BitWidth = Value.getBitWidth(); 4283 APSInt ActualValue(Value.sext(BitWidth + 1), /*IsUnsigned*/false); 4284 ActualValue.setBit(BitWidth); 4285 return HandleOverflow(Info, E, ActualValue, SubobjType); 4286 } 4287 } 4288 return true; 4289 } 4290 bool found(APFloat &Value, QualType SubobjType) { 4291 if (!checkConst(SubobjType)) 4292 return false; 4293 4294 if (Old) *Old = APValue(Value); 4295 4296 APFloat One(Value.getSemantics(), 1); 4297 if (AccessKind == AK_Increment) 4298 Value.add(One, APFloat::rmNearestTiesToEven); 4299 else 4300 Value.subtract(One, APFloat::rmNearestTiesToEven); 4301 return true; 4302 } 4303 bool foundPointer(APValue &Subobj, QualType SubobjType) { 4304 if (!checkConst(SubobjType)) 4305 return false; 4306 4307 QualType PointeeType; 4308 if (const PointerType *PT = SubobjType->getAs<PointerType>()) 4309 PointeeType = PT->getPointeeType(); 4310 else { 4311 Info.FFDiag(E); 4312 return false; 4313 } 4314 4315 LValue LVal; 4316 LVal.setFrom(Info.Ctx, Subobj); 4317 if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType, 4318 AccessKind == AK_Increment ? 1 : -1)) 4319 return false; 4320 LVal.moveInto(Subobj); 4321 return true; 4322 } 4323 }; 4324 } // end anonymous namespace 4325 4326 /// Perform an increment or decrement on LVal. 4327 static bool handleIncDec(EvalInfo &Info, const Expr *E, const LValue &LVal, 4328 QualType LValType, bool IsIncrement, APValue *Old) { 4329 if (LVal.Designator.Invalid) 4330 return false; 4331 4332 if (!Info.getLangOpts().CPlusPlus14) { 4333 Info.FFDiag(E); 4334 return false; 4335 } 4336 4337 AccessKinds AK = IsIncrement ? AK_Increment : AK_Decrement; 4338 CompleteObject Obj = findCompleteObject(Info, E, AK, LVal, LValType); 4339 IncDecSubobjectHandler Handler = {Info, cast<UnaryOperator>(E), AK, Old}; 4340 return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler); 4341 } 4342 4343 /// Build an lvalue for the object argument of a member function call. 4344 static bool EvaluateObjectArgument(EvalInfo &Info, const Expr *Object, 4345 LValue &This) { 4346 if (Object->getType()->isPointerType() && Object->isRValue()) 4347 return EvaluatePointer(Object, This, Info); 4348 4349 if (Object->isGLValue()) 4350 return EvaluateLValue(Object, This, Info); 4351 4352 if (Object->getType()->isLiteralType(Info.Ctx)) 4353 return EvaluateTemporary(Object, This, Info); 4354 4355 Info.FFDiag(Object, diag::note_constexpr_nonliteral) << Object->getType(); 4356 return false; 4357 } 4358 4359 /// HandleMemberPointerAccess - Evaluate a member access operation and build an 4360 /// lvalue referring to the result. 4361 /// 4362 /// \param Info - Information about the ongoing evaluation. 4363 /// \param LV - An lvalue referring to the base of the member pointer. 4364 /// \param RHS - The member pointer expression. 4365 /// \param IncludeMember - Specifies whether the member itself is included in 4366 /// the resulting LValue subobject designator. This is not possible when 4367 /// creating a bound member function. 4368 /// \return The field or method declaration to which the member pointer refers, 4369 /// or 0 if evaluation fails. 4370 static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info, 4371 QualType LVType, 4372 LValue &LV, 4373 const Expr *RHS, 4374 bool IncludeMember = true) { 4375 MemberPtr MemPtr; 4376 if (!EvaluateMemberPointer(RHS, MemPtr, Info)) 4377 return nullptr; 4378 4379 // C++11 [expr.mptr.oper]p6: If the second operand is the null pointer to 4380 // member value, the behavior is undefined. 4381 if (!MemPtr.getDecl()) { 4382 // FIXME: Specific diagnostic. 4383 Info.FFDiag(RHS); 4384 return nullptr; 4385 } 4386 4387 if (MemPtr.isDerivedMember()) { 4388 // This is a member of some derived class. Truncate LV appropriately. 4389 // The end of the derived-to-base path for the base object must match the 4390 // derived-to-base path for the member pointer. 4391 if (LV.Designator.MostDerivedPathLength + MemPtr.Path.size() > 4392 LV.Designator.Entries.size()) { 4393 Info.FFDiag(RHS); 4394 return nullptr; 4395 } 4396 unsigned PathLengthToMember = 4397 LV.Designator.Entries.size() - MemPtr.Path.size(); 4398 for (unsigned I = 0, N = MemPtr.Path.size(); I != N; ++I) { 4399 const CXXRecordDecl *LVDecl = getAsBaseClass( 4400 LV.Designator.Entries[PathLengthToMember + I]); 4401 const CXXRecordDecl *MPDecl = MemPtr.Path[I]; 4402 if (LVDecl->getCanonicalDecl() != MPDecl->getCanonicalDecl()) { 4403 Info.FFDiag(RHS); 4404 return nullptr; 4405 } 4406 } 4407 4408 // Truncate the lvalue to the appropriate derived class. 4409 if (!CastToDerivedClass(Info, RHS, LV, MemPtr.getContainingRecord(), 4410 PathLengthToMember)) 4411 return nullptr; 4412 } else if (!MemPtr.Path.empty()) { 4413 // Extend the LValue path with the member pointer's path. 4414 LV.Designator.Entries.reserve(LV.Designator.Entries.size() + 4415 MemPtr.Path.size() + IncludeMember); 4416 4417 // Walk down to the appropriate base class. 4418 if (const PointerType *PT = LVType->getAs<PointerType>()) 4419 LVType = PT->getPointeeType(); 4420 const CXXRecordDecl *RD = LVType->getAsCXXRecordDecl(); 4421 assert(RD && "member pointer access on non-class-type expression"); 4422 // The first class in the path is that of the lvalue. 4423 for (unsigned I = 1, N = MemPtr.Path.size(); I != N; ++I) { 4424 const CXXRecordDecl *Base = MemPtr.Path[N - I - 1]; 4425 if (!HandleLValueDirectBase(Info, RHS, LV, RD, Base)) 4426 return nullptr; 4427 RD = Base; 4428 } 4429 // Finally cast to the class containing the member. 4430 if (!HandleLValueDirectBase(Info, RHS, LV, RD, 4431 MemPtr.getContainingRecord())) 4432 return nullptr; 4433 } 4434 4435 // Add the member. Note that we cannot build bound member functions here. 4436 if (IncludeMember) { 4437 if (const FieldDecl *FD = dyn_cast<FieldDecl>(MemPtr.getDecl())) { 4438 if (!HandleLValueMember(Info, RHS, LV, FD)) 4439 return nullptr; 4440 } else if (const IndirectFieldDecl *IFD = 4441 dyn_cast<IndirectFieldDecl>(MemPtr.getDecl())) { 4442 if (!HandleLValueIndirectMember(Info, RHS, LV, IFD)) 4443 return nullptr; 4444 } else { 4445 llvm_unreachable("can't construct reference to bound member function"); 4446 } 4447 } 4448 4449 return MemPtr.getDecl(); 4450 } 4451 4452 static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info, 4453 const BinaryOperator *BO, 4454 LValue &LV, 4455 bool IncludeMember = true) { 4456 assert(BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI); 4457 4458 if (!EvaluateObjectArgument(Info, BO->getLHS(), LV)) { 4459 if (Info.noteFailure()) { 4460 MemberPtr MemPtr; 4461 EvaluateMemberPointer(BO->getRHS(), MemPtr, Info); 4462 } 4463 return nullptr; 4464 } 4465 4466 return HandleMemberPointerAccess(Info, BO->getLHS()->getType(), LV, 4467 BO->getRHS(), IncludeMember); 4468 } 4469 4470 /// HandleBaseToDerivedCast - Apply the given base-to-derived cast operation on 4471 /// the provided lvalue, which currently refers to the base object. 4472 static bool HandleBaseToDerivedCast(EvalInfo &Info, const CastExpr *E, 4473 LValue &Result) { 4474 SubobjectDesignator &D = Result.Designator; 4475 if (D.Invalid || !Result.checkNullPointer(Info, E, CSK_Derived)) 4476 return false; 4477 4478 QualType TargetQT = E->getType(); 4479 if (const PointerType *PT = TargetQT->getAs<PointerType>()) 4480 TargetQT = PT->getPointeeType(); 4481 4482 // Check this cast lands within the final derived-to-base subobject path. 4483 if (D.MostDerivedPathLength + E->path_size() > D.Entries.size()) { 4484 Info.CCEDiag(E, diag::note_constexpr_invalid_downcast) 4485 << D.MostDerivedType << TargetQT; 4486 return false; 4487 } 4488 4489 // Check the type of the final cast. We don't need to check the path, 4490 // since a cast can only be formed if the path is unique. 4491 unsigned NewEntriesSize = D.Entries.size() - E->path_size(); 4492 const CXXRecordDecl *TargetType = TargetQT->getAsCXXRecordDecl(); 4493 const CXXRecordDecl *FinalType; 4494 if (NewEntriesSize == D.MostDerivedPathLength) 4495 FinalType = D.MostDerivedType->getAsCXXRecordDecl(); 4496 else 4497 FinalType = getAsBaseClass(D.Entries[NewEntriesSize - 1]); 4498 if (FinalType->getCanonicalDecl() != TargetType->getCanonicalDecl()) { 4499 Info.CCEDiag(E, diag::note_constexpr_invalid_downcast) 4500 << D.MostDerivedType << TargetQT; 4501 return false; 4502 } 4503 4504 // Truncate the lvalue to the appropriate derived class. 4505 return CastToDerivedClass(Info, E, Result, TargetType, NewEntriesSize); 4506 } 4507 4508 /// Get the value to use for a default-initialized object of type T. 4509 /// Return false if it encounters something invalid. 4510 static bool getDefaultInitValue(QualType T, APValue &Result) { 4511 bool Success = true; 4512 if (auto *RD = T->getAsCXXRecordDecl()) { 4513 if (RD->isInvalidDecl()) { 4514 Result = APValue(); 4515 return false; 4516 } 4517 if (RD->isUnion()) { 4518 Result = APValue((const FieldDecl *)nullptr); 4519 return true; 4520 } 4521 Result = APValue(APValue::UninitStruct(), RD->getNumBases(), 4522 std::distance(RD->field_begin(), RD->field_end())); 4523 4524 unsigned Index = 0; 4525 for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(), 4526 End = RD->bases_end(); 4527 I != End; ++I, ++Index) 4528 Success &= getDefaultInitValue(I->getType(), Result.getStructBase(Index)); 4529 4530 for (const auto *I : RD->fields()) { 4531 if (I->isUnnamedBitfield()) 4532 continue; 4533 Success &= getDefaultInitValue(I->getType(), 4534 Result.getStructField(I->getFieldIndex())); 4535 } 4536 return Success; 4537 } 4538 4539 if (auto *AT = 4540 dyn_cast_or_null<ConstantArrayType>(T->getAsArrayTypeUnsafe())) { 4541 Result = APValue(APValue::UninitArray(), 0, AT->getSize().getZExtValue()); 4542 if (Result.hasArrayFiller()) 4543 Success &= 4544 getDefaultInitValue(AT->getElementType(), Result.getArrayFiller()); 4545 4546 return Success; 4547 } 4548 4549 Result = APValue::IndeterminateValue(); 4550 return true; 4551 } 4552 4553 namespace { 4554 enum EvalStmtResult { 4555 /// Evaluation failed. 4556 ESR_Failed, 4557 /// Hit a 'return' statement. 4558 ESR_Returned, 4559 /// Evaluation succeeded. 4560 ESR_Succeeded, 4561 /// Hit a 'continue' statement. 4562 ESR_Continue, 4563 /// Hit a 'break' statement. 4564 ESR_Break, 4565 /// Still scanning for 'case' or 'default' statement. 4566 ESR_CaseNotFound 4567 }; 4568 } 4569 4570 static bool EvaluateVarDecl(EvalInfo &Info, const VarDecl *VD) { 4571 // We don't need to evaluate the initializer for a static local. 4572 if (!VD->hasLocalStorage()) 4573 return true; 4574 4575 LValue Result; 4576 APValue &Val = 4577 Info.CurrentCall->createTemporary(VD, VD->getType(), true, Result); 4578 4579 const Expr *InitE = VD->getInit(); 4580 if (!InitE) 4581 return getDefaultInitValue(VD->getType(), Val); 4582 4583 if (InitE->isValueDependent()) 4584 return false; 4585 4586 if (!EvaluateInPlace(Val, Info, Result, InitE)) { 4587 // Wipe out any partially-computed value, to allow tracking that this 4588 // evaluation failed. 4589 Val = APValue(); 4590 return false; 4591 } 4592 4593 return true; 4594 } 4595 4596 static bool EvaluateDecl(EvalInfo &Info, const Decl *D) { 4597 bool OK = true; 4598 4599 if (const VarDecl *VD = dyn_cast<VarDecl>(D)) 4600 OK &= EvaluateVarDecl(Info, VD); 4601 4602 if (const DecompositionDecl *DD = dyn_cast<DecompositionDecl>(D)) 4603 for (auto *BD : DD->bindings()) 4604 if (auto *VD = BD->getHoldingVar()) 4605 OK &= EvaluateDecl(Info, VD); 4606 4607 return OK; 4608 } 4609 4610 4611 /// Evaluate a condition (either a variable declaration or an expression). 4612 static bool EvaluateCond(EvalInfo &Info, const VarDecl *CondDecl, 4613 const Expr *Cond, bool &Result) { 4614 FullExpressionRAII Scope(Info); 4615 if (CondDecl && !EvaluateDecl(Info, CondDecl)) 4616 return false; 4617 if (!EvaluateAsBooleanCondition(Cond, Result, Info)) 4618 return false; 4619 return Scope.destroy(); 4620 } 4621 4622 namespace { 4623 /// A location where the result (returned value) of evaluating a 4624 /// statement should be stored. 4625 struct StmtResult { 4626 /// The APValue that should be filled in with the returned value. 4627 APValue &Value; 4628 /// The location containing the result, if any (used to support RVO). 4629 const LValue *Slot; 4630 }; 4631 4632 struct TempVersionRAII { 4633 CallStackFrame &Frame; 4634 4635 TempVersionRAII(CallStackFrame &Frame) : Frame(Frame) { 4636 Frame.pushTempVersion(); 4637 } 4638 4639 ~TempVersionRAII() { 4640 Frame.popTempVersion(); 4641 } 4642 }; 4643 4644 } 4645 4646 static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info, 4647 const Stmt *S, 4648 const SwitchCase *SC = nullptr); 4649 4650 /// Evaluate the body of a loop, and translate the result as appropriate. 4651 static EvalStmtResult EvaluateLoopBody(StmtResult &Result, EvalInfo &Info, 4652 const Stmt *Body, 4653 const SwitchCase *Case = nullptr) { 4654 BlockScopeRAII Scope(Info); 4655 4656 EvalStmtResult ESR = EvaluateStmt(Result, Info, Body, Case); 4657 if (ESR != ESR_Failed && ESR != ESR_CaseNotFound && !Scope.destroy()) 4658 ESR = ESR_Failed; 4659 4660 switch (ESR) { 4661 case ESR_Break: 4662 return ESR_Succeeded; 4663 case ESR_Succeeded: 4664 case ESR_Continue: 4665 return ESR_Continue; 4666 case ESR_Failed: 4667 case ESR_Returned: 4668 case ESR_CaseNotFound: 4669 return ESR; 4670 } 4671 llvm_unreachable("Invalid EvalStmtResult!"); 4672 } 4673 4674 /// Evaluate a switch statement. 4675 static EvalStmtResult EvaluateSwitch(StmtResult &Result, EvalInfo &Info, 4676 const SwitchStmt *SS) { 4677 BlockScopeRAII Scope(Info); 4678 4679 // Evaluate the switch condition. 4680 APSInt Value; 4681 { 4682 if (const Stmt *Init = SS->getInit()) { 4683 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init); 4684 if (ESR != ESR_Succeeded) { 4685 if (ESR != ESR_Failed && !Scope.destroy()) 4686 ESR = ESR_Failed; 4687 return ESR; 4688 } 4689 } 4690 4691 FullExpressionRAII CondScope(Info); 4692 if (SS->getConditionVariable() && 4693 !EvaluateDecl(Info, SS->getConditionVariable())) 4694 return ESR_Failed; 4695 if (!EvaluateInteger(SS->getCond(), Value, Info)) 4696 return ESR_Failed; 4697 if (!CondScope.destroy()) 4698 return ESR_Failed; 4699 } 4700 4701 // Find the switch case corresponding to the value of the condition. 4702 // FIXME: Cache this lookup. 4703 const SwitchCase *Found = nullptr; 4704 for (const SwitchCase *SC = SS->getSwitchCaseList(); SC; 4705 SC = SC->getNextSwitchCase()) { 4706 if (isa<DefaultStmt>(SC)) { 4707 Found = SC; 4708 continue; 4709 } 4710 4711 const CaseStmt *CS = cast<CaseStmt>(SC); 4712 APSInt LHS = CS->getLHS()->EvaluateKnownConstInt(Info.Ctx); 4713 APSInt RHS = CS->getRHS() ? CS->getRHS()->EvaluateKnownConstInt(Info.Ctx) 4714 : LHS; 4715 if (LHS <= Value && Value <= RHS) { 4716 Found = SC; 4717 break; 4718 } 4719 } 4720 4721 if (!Found) 4722 return Scope.destroy() ? ESR_Succeeded : ESR_Failed; 4723 4724 // Search the switch body for the switch case and evaluate it from there. 4725 EvalStmtResult ESR = EvaluateStmt(Result, Info, SS->getBody(), Found); 4726 if (ESR != ESR_Failed && ESR != ESR_CaseNotFound && !Scope.destroy()) 4727 return ESR_Failed; 4728 4729 switch (ESR) { 4730 case ESR_Break: 4731 return ESR_Succeeded; 4732 case ESR_Succeeded: 4733 case ESR_Continue: 4734 case ESR_Failed: 4735 case ESR_Returned: 4736 return ESR; 4737 case ESR_CaseNotFound: 4738 // This can only happen if the switch case is nested within a statement 4739 // expression. We have no intention of supporting that. 4740 Info.FFDiag(Found->getBeginLoc(), 4741 diag::note_constexpr_stmt_expr_unsupported); 4742 return ESR_Failed; 4743 } 4744 llvm_unreachable("Invalid EvalStmtResult!"); 4745 } 4746 4747 // Evaluate a statement. 4748 static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info, 4749 const Stmt *S, const SwitchCase *Case) { 4750 if (!Info.nextStep(S)) 4751 return ESR_Failed; 4752 4753 // If we're hunting down a 'case' or 'default' label, recurse through 4754 // substatements until we hit the label. 4755 if (Case) { 4756 switch (S->getStmtClass()) { 4757 case Stmt::CompoundStmtClass: 4758 // FIXME: Precompute which substatement of a compound statement we 4759 // would jump to, and go straight there rather than performing a 4760 // linear scan each time. 4761 case Stmt::LabelStmtClass: 4762 case Stmt::AttributedStmtClass: 4763 case Stmt::DoStmtClass: 4764 break; 4765 4766 case Stmt::CaseStmtClass: 4767 case Stmt::DefaultStmtClass: 4768 if (Case == S) 4769 Case = nullptr; 4770 break; 4771 4772 case Stmt::IfStmtClass: { 4773 // FIXME: Precompute which side of an 'if' we would jump to, and go 4774 // straight there rather than scanning both sides. 4775 const IfStmt *IS = cast<IfStmt>(S); 4776 4777 // Wrap the evaluation in a block scope, in case it's a DeclStmt 4778 // preceded by our switch label. 4779 BlockScopeRAII Scope(Info); 4780 4781 // Step into the init statement in case it brings an (uninitialized) 4782 // variable into scope. 4783 if (const Stmt *Init = IS->getInit()) { 4784 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init, Case); 4785 if (ESR != ESR_CaseNotFound) { 4786 assert(ESR != ESR_Succeeded); 4787 return ESR; 4788 } 4789 } 4790 4791 // Condition variable must be initialized if it exists. 4792 // FIXME: We can skip evaluating the body if there's a condition 4793 // variable, as there can't be any case labels within it. 4794 // (The same is true for 'for' statements.) 4795 4796 EvalStmtResult ESR = EvaluateStmt(Result, Info, IS->getThen(), Case); 4797 if (ESR == ESR_Failed) 4798 return ESR; 4799 if (ESR != ESR_CaseNotFound) 4800 return Scope.destroy() ? ESR : ESR_Failed; 4801 if (!IS->getElse()) 4802 return ESR_CaseNotFound; 4803 4804 ESR = EvaluateStmt(Result, Info, IS->getElse(), Case); 4805 if (ESR == ESR_Failed) 4806 return ESR; 4807 if (ESR != ESR_CaseNotFound) 4808 return Scope.destroy() ? ESR : ESR_Failed; 4809 return ESR_CaseNotFound; 4810 } 4811 4812 case Stmt::WhileStmtClass: { 4813 EvalStmtResult ESR = 4814 EvaluateLoopBody(Result, Info, cast<WhileStmt>(S)->getBody(), Case); 4815 if (ESR != ESR_Continue) 4816 return ESR; 4817 break; 4818 } 4819 4820 case Stmt::ForStmtClass: { 4821 const ForStmt *FS = cast<ForStmt>(S); 4822 BlockScopeRAII Scope(Info); 4823 4824 // Step into the init statement in case it brings an (uninitialized) 4825 // variable into scope. 4826 if (const Stmt *Init = FS->getInit()) { 4827 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init, Case); 4828 if (ESR != ESR_CaseNotFound) { 4829 assert(ESR != ESR_Succeeded); 4830 return ESR; 4831 } 4832 } 4833 4834 EvalStmtResult ESR = 4835 EvaluateLoopBody(Result, Info, FS->getBody(), Case); 4836 if (ESR != ESR_Continue) 4837 return ESR; 4838 if (FS->getInc()) { 4839 FullExpressionRAII IncScope(Info); 4840 if (!EvaluateIgnoredValue(Info, FS->getInc()) || !IncScope.destroy()) 4841 return ESR_Failed; 4842 } 4843 break; 4844 } 4845 4846 case Stmt::DeclStmtClass: { 4847 // Start the lifetime of any uninitialized variables we encounter. They 4848 // might be used by the selected branch of the switch. 4849 const DeclStmt *DS = cast<DeclStmt>(S); 4850 for (const auto *D : DS->decls()) { 4851 if (const auto *VD = dyn_cast<VarDecl>(D)) { 4852 if (VD->hasLocalStorage() && !VD->getInit()) 4853 if (!EvaluateVarDecl(Info, VD)) 4854 return ESR_Failed; 4855 // FIXME: If the variable has initialization that can't be jumped 4856 // over, bail out of any immediately-surrounding compound-statement 4857 // too. There can't be any case labels here. 4858 } 4859 } 4860 return ESR_CaseNotFound; 4861 } 4862 4863 default: 4864 return ESR_CaseNotFound; 4865 } 4866 } 4867 4868 switch (S->getStmtClass()) { 4869 default: 4870 if (const Expr *E = dyn_cast<Expr>(S)) { 4871 // Don't bother evaluating beyond an expression-statement which couldn't 4872 // be evaluated. 4873 // FIXME: Do we need the FullExpressionRAII object here? 4874 // VisitExprWithCleanups should create one when necessary. 4875 FullExpressionRAII Scope(Info); 4876 if (!EvaluateIgnoredValue(Info, E) || !Scope.destroy()) 4877 return ESR_Failed; 4878 return ESR_Succeeded; 4879 } 4880 4881 Info.FFDiag(S->getBeginLoc()); 4882 return ESR_Failed; 4883 4884 case Stmt::NullStmtClass: 4885 return ESR_Succeeded; 4886 4887 case Stmt::DeclStmtClass: { 4888 const DeclStmt *DS = cast<DeclStmt>(S); 4889 for (const auto *D : DS->decls()) { 4890 // Each declaration initialization is its own full-expression. 4891 FullExpressionRAII Scope(Info); 4892 if (!EvaluateDecl(Info, D) && !Info.noteFailure()) 4893 return ESR_Failed; 4894 if (!Scope.destroy()) 4895 return ESR_Failed; 4896 } 4897 return ESR_Succeeded; 4898 } 4899 4900 case Stmt::ReturnStmtClass: { 4901 const Expr *RetExpr = cast<ReturnStmt>(S)->getRetValue(); 4902 FullExpressionRAII Scope(Info); 4903 if (RetExpr && 4904 !(Result.Slot 4905 ? EvaluateInPlace(Result.Value, Info, *Result.Slot, RetExpr) 4906 : Evaluate(Result.Value, Info, RetExpr))) 4907 return ESR_Failed; 4908 return Scope.destroy() ? ESR_Returned : ESR_Failed; 4909 } 4910 4911 case Stmt::CompoundStmtClass: { 4912 BlockScopeRAII Scope(Info); 4913 4914 const CompoundStmt *CS = cast<CompoundStmt>(S); 4915 for (const auto *BI : CS->body()) { 4916 EvalStmtResult ESR = EvaluateStmt(Result, Info, BI, Case); 4917 if (ESR == ESR_Succeeded) 4918 Case = nullptr; 4919 else if (ESR != ESR_CaseNotFound) { 4920 if (ESR != ESR_Failed && !Scope.destroy()) 4921 return ESR_Failed; 4922 return ESR; 4923 } 4924 } 4925 if (Case) 4926 return ESR_CaseNotFound; 4927 return Scope.destroy() ? ESR_Succeeded : ESR_Failed; 4928 } 4929 4930 case Stmt::IfStmtClass: { 4931 const IfStmt *IS = cast<IfStmt>(S); 4932 4933 // Evaluate the condition, as either a var decl or as an expression. 4934 BlockScopeRAII Scope(Info); 4935 if (const Stmt *Init = IS->getInit()) { 4936 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init); 4937 if (ESR != ESR_Succeeded) { 4938 if (ESR != ESR_Failed && !Scope.destroy()) 4939 return ESR_Failed; 4940 return ESR; 4941 } 4942 } 4943 bool Cond; 4944 if (!EvaluateCond(Info, IS->getConditionVariable(), IS->getCond(), Cond)) 4945 return ESR_Failed; 4946 4947 if (const Stmt *SubStmt = Cond ? IS->getThen() : IS->getElse()) { 4948 EvalStmtResult ESR = EvaluateStmt(Result, Info, SubStmt); 4949 if (ESR != ESR_Succeeded) { 4950 if (ESR != ESR_Failed && !Scope.destroy()) 4951 return ESR_Failed; 4952 return ESR; 4953 } 4954 } 4955 return Scope.destroy() ? ESR_Succeeded : ESR_Failed; 4956 } 4957 4958 case Stmt::WhileStmtClass: { 4959 const WhileStmt *WS = cast<WhileStmt>(S); 4960 while (true) { 4961 BlockScopeRAII Scope(Info); 4962 bool Continue; 4963 if (!EvaluateCond(Info, WS->getConditionVariable(), WS->getCond(), 4964 Continue)) 4965 return ESR_Failed; 4966 if (!Continue) 4967 break; 4968 4969 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, WS->getBody()); 4970 if (ESR != ESR_Continue) { 4971 if (ESR != ESR_Failed && !Scope.destroy()) 4972 return ESR_Failed; 4973 return ESR; 4974 } 4975 if (!Scope.destroy()) 4976 return ESR_Failed; 4977 } 4978 return ESR_Succeeded; 4979 } 4980 4981 case Stmt::DoStmtClass: { 4982 const DoStmt *DS = cast<DoStmt>(S); 4983 bool Continue; 4984 do { 4985 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, DS->getBody(), Case); 4986 if (ESR != ESR_Continue) 4987 return ESR; 4988 Case = nullptr; 4989 4990 FullExpressionRAII CondScope(Info); 4991 if (!EvaluateAsBooleanCondition(DS->getCond(), Continue, Info) || 4992 !CondScope.destroy()) 4993 return ESR_Failed; 4994 } while (Continue); 4995 return ESR_Succeeded; 4996 } 4997 4998 case Stmt::ForStmtClass: { 4999 const ForStmt *FS = cast<ForStmt>(S); 5000 BlockScopeRAII ForScope(Info); 5001 if (FS->getInit()) { 5002 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getInit()); 5003 if (ESR != ESR_Succeeded) { 5004 if (ESR != ESR_Failed && !ForScope.destroy()) 5005 return ESR_Failed; 5006 return ESR; 5007 } 5008 } 5009 while (true) { 5010 BlockScopeRAII IterScope(Info); 5011 bool Continue = true; 5012 if (FS->getCond() && !EvaluateCond(Info, FS->getConditionVariable(), 5013 FS->getCond(), Continue)) 5014 return ESR_Failed; 5015 if (!Continue) 5016 break; 5017 5018 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, FS->getBody()); 5019 if (ESR != ESR_Continue) { 5020 if (ESR != ESR_Failed && (!IterScope.destroy() || !ForScope.destroy())) 5021 return ESR_Failed; 5022 return ESR; 5023 } 5024 5025 if (FS->getInc()) { 5026 FullExpressionRAII IncScope(Info); 5027 if (!EvaluateIgnoredValue(Info, FS->getInc()) || !IncScope.destroy()) 5028 return ESR_Failed; 5029 } 5030 5031 if (!IterScope.destroy()) 5032 return ESR_Failed; 5033 } 5034 return ForScope.destroy() ? ESR_Succeeded : ESR_Failed; 5035 } 5036 5037 case Stmt::CXXForRangeStmtClass: { 5038 const CXXForRangeStmt *FS = cast<CXXForRangeStmt>(S); 5039 BlockScopeRAII Scope(Info); 5040 5041 // Evaluate the init-statement if present. 5042 if (FS->getInit()) { 5043 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getInit()); 5044 if (ESR != ESR_Succeeded) { 5045 if (ESR != ESR_Failed && !Scope.destroy()) 5046 return ESR_Failed; 5047 return ESR; 5048 } 5049 } 5050 5051 // Initialize the __range variable. 5052 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getRangeStmt()); 5053 if (ESR != ESR_Succeeded) { 5054 if (ESR != ESR_Failed && !Scope.destroy()) 5055 return ESR_Failed; 5056 return ESR; 5057 } 5058 5059 // Create the __begin and __end iterators. 5060 ESR = EvaluateStmt(Result, Info, FS->getBeginStmt()); 5061 if (ESR != ESR_Succeeded) { 5062 if (ESR != ESR_Failed && !Scope.destroy()) 5063 return ESR_Failed; 5064 return ESR; 5065 } 5066 ESR = EvaluateStmt(Result, Info, FS->getEndStmt()); 5067 if (ESR != ESR_Succeeded) { 5068 if (ESR != ESR_Failed && !Scope.destroy()) 5069 return ESR_Failed; 5070 return ESR; 5071 } 5072 5073 while (true) { 5074 // Condition: __begin != __end. 5075 { 5076 bool Continue = true; 5077 FullExpressionRAII CondExpr(Info); 5078 if (!EvaluateAsBooleanCondition(FS->getCond(), Continue, Info)) 5079 return ESR_Failed; 5080 if (!Continue) 5081 break; 5082 } 5083 5084 // User's variable declaration, initialized by *__begin. 5085 BlockScopeRAII InnerScope(Info); 5086 ESR = EvaluateStmt(Result, Info, FS->getLoopVarStmt()); 5087 if (ESR != ESR_Succeeded) { 5088 if (ESR != ESR_Failed && (!InnerScope.destroy() || !Scope.destroy())) 5089 return ESR_Failed; 5090 return ESR; 5091 } 5092 5093 // Loop body. 5094 ESR = EvaluateLoopBody(Result, Info, FS->getBody()); 5095 if (ESR != ESR_Continue) { 5096 if (ESR != ESR_Failed && (!InnerScope.destroy() || !Scope.destroy())) 5097 return ESR_Failed; 5098 return ESR; 5099 } 5100 5101 // Increment: ++__begin 5102 if (!EvaluateIgnoredValue(Info, FS->getInc())) 5103 return ESR_Failed; 5104 5105 if (!InnerScope.destroy()) 5106 return ESR_Failed; 5107 } 5108 5109 return Scope.destroy() ? ESR_Succeeded : ESR_Failed; 5110 } 5111 5112 case Stmt::SwitchStmtClass: 5113 return EvaluateSwitch(Result, Info, cast<SwitchStmt>(S)); 5114 5115 case Stmt::ContinueStmtClass: 5116 return ESR_Continue; 5117 5118 case Stmt::BreakStmtClass: 5119 return ESR_Break; 5120 5121 case Stmt::LabelStmtClass: 5122 return EvaluateStmt(Result, Info, cast<LabelStmt>(S)->getSubStmt(), Case); 5123 5124 case Stmt::AttributedStmtClass: 5125 // As a general principle, C++11 attributes can be ignored without 5126 // any semantic impact. 5127 return EvaluateStmt(Result, Info, cast<AttributedStmt>(S)->getSubStmt(), 5128 Case); 5129 5130 case Stmt::CaseStmtClass: 5131 case Stmt::DefaultStmtClass: 5132 return EvaluateStmt(Result, Info, cast<SwitchCase>(S)->getSubStmt(), Case); 5133 case Stmt::CXXTryStmtClass: 5134 // Evaluate try blocks by evaluating all sub statements. 5135 return EvaluateStmt(Result, Info, cast<CXXTryStmt>(S)->getTryBlock(), Case); 5136 } 5137 } 5138 5139 /// CheckTrivialDefaultConstructor - Check whether a constructor is a trivial 5140 /// default constructor. If so, we'll fold it whether or not it's marked as 5141 /// constexpr. If it is marked as constexpr, we will never implicitly define it, 5142 /// so we need special handling. 5143 static bool CheckTrivialDefaultConstructor(EvalInfo &Info, SourceLocation Loc, 5144 const CXXConstructorDecl *CD, 5145 bool IsValueInitialization) { 5146 if (!CD->isTrivial() || !CD->isDefaultConstructor()) 5147 return false; 5148 5149 // Value-initialization does not call a trivial default constructor, so such a 5150 // call is a core constant expression whether or not the constructor is 5151 // constexpr. 5152 if (!CD->isConstexpr() && !IsValueInitialization) { 5153 if (Info.getLangOpts().CPlusPlus11) { 5154 // FIXME: If DiagDecl is an implicitly-declared special member function, 5155 // we should be much more explicit about why it's not constexpr. 5156 Info.CCEDiag(Loc, diag::note_constexpr_invalid_function, 1) 5157 << /*IsConstexpr*/0 << /*IsConstructor*/1 << CD; 5158 Info.Note(CD->getLocation(), diag::note_declared_at); 5159 } else { 5160 Info.CCEDiag(Loc, diag::note_invalid_subexpr_in_const_expr); 5161 } 5162 } 5163 return true; 5164 } 5165 5166 /// CheckConstexprFunction - Check that a function can be called in a constant 5167 /// expression. 5168 static bool CheckConstexprFunction(EvalInfo &Info, SourceLocation CallLoc, 5169 const FunctionDecl *Declaration, 5170 const FunctionDecl *Definition, 5171 const Stmt *Body) { 5172 // Potential constant expressions can contain calls to declared, but not yet 5173 // defined, constexpr functions. 5174 if (Info.checkingPotentialConstantExpression() && !Definition && 5175 Declaration->isConstexpr()) 5176 return false; 5177 5178 // Bail out if the function declaration itself is invalid. We will 5179 // have produced a relevant diagnostic while parsing it, so just 5180 // note the problematic sub-expression. 5181 if (Declaration->isInvalidDecl()) { 5182 Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr); 5183 return false; 5184 } 5185 5186 // DR1872: An instantiated virtual constexpr function can't be called in a 5187 // constant expression (prior to C++20). We can still constant-fold such a 5188 // call. 5189 if (!Info.Ctx.getLangOpts().CPlusPlus20 && isa<CXXMethodDecl>(Declaration) && 5190 cast<CXXMethodDecl>(Declaration)->isVirtual()) 5191 Info.CCEDiag(CallLoc, diag::note_constexpr_virtual_call); 5192 5193 if (Definition && Definition->isInvalidDecl()) { 5194 Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr); 5195 return false; 5196 } 5197 5198 if (const auto *CtorDecl = dyn_cast_or_null<CXXConstructorDecl>(Definition)) { 5199 for (const auto *InitExpr : CtorDecl->inits()) { 5200 if (InitExpr->getInit() && InitExpr->getInit()->containsErrors()) 5201 return false; 5202 } 5203 } 5204 5205 // Can we evaluate this function call? 5206 if (Definition && Definition->isConstexpr() && Body) 5207 return true; 5208 5209 if (Info.getLangOpts().CPlusPlus11) { 5210 const FunctionDecl *DiagDecl = Definition ? Definition : Declaration; 5211 5212 // If this function is not constexpr because it is an inherited 5213 // non-constexpr constructor, diagnose that directly. 5214 auto *CD = dyn_cast<CXXConstructorDecl>(DiagDecl); 5215 if (CD && CD->isInheritingConstructor()) { 5216 auto *Inherited = CD->getInheritedConstructor().getConstructor(); 5217 if (!Inherited->isConstexpr()) 5218 DiagDecl = CD = Inherited; 5219 } 5220 5221 // FIXME: If DiagDecl is an implicitly-declared special member function 5222 // or an inheriting constructor, we should be much more explicit about why 5223 // it's not constexpr. 5224 if (CD && CD->isInheritingConstructor()) 5225 Info.FFDiag(CallLoc, diag::note_constexpr_invalid_inhctor, 1) 5226 << CD->getInheritedConstructor().getConstructor()->getParent(); 5227 else 5228 Info.FFDiag(CallLoc, diag::note_constexpr_invalid_function, 1) 5229 << DiagDecl->isConstexpr() << (bool)CD << DiagDecl; 5230 Info.Note(DiagDecl->getLocation(), diag::note_declared_at); 5231 } else { 5232 Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr); 5233 } 5234 return false; 5235 } 5236 5237 namespace { 5238 struct CheckDynamicTypeHandler { 5239 AccessKinds AccessKind; 5240 typedef bool result_type; 5241 bool failed() { return false; } 5242 bool found(APValue &Subobj, QualType SubobjType) { return true; } 5243 bool found(APSInt &Value, QualType SubobjType) { return true; } 5244 bool found(APFloat &Value, QualType SubobjType) { return true; } 5245 }; 5246 } // end anonymous namespace 5247 5248 /// Check that we can access the notional vptr of an object / determine its 5249 /// dynamic type. 5250 static bool checkDynamicType(EvalInfo &Info, const Expr *E, const LValue &This, 5251 AccessKinds AK, bool Polymorphic) { 5252 if (This.Designator.Invalid) 5253 return false; 5254 5255 CompleteObject Obj = findCompleteObject(Info, E, AK, This, QualType()); 5256 5257 if (!Obj) 5258 return false; 5259 5260 if (!Obj.Value) { 5261 // The object is not usable in constant expressions, so we can't inspect 5262 // its value to see if it's in-lifetime or what the active union members 5263 // are. We can still check for a one-past-the-end lvalue. 5264 if (This.Designator.isOnePastTheEnd() || 5265 This.Designator.isMostDerivedAnUnsizedArray()) { 5266 Info.FFDiag(E, This.Designator.isOnePastTheEnd() 5267 ? diag::note_constexpr_access_past_end 5268 : diag::note_constexpr_access_unsized_array) 5269 << AK; 5270 return false; 5271 } else if (Polymorphic) { 5272 // Conservatively refuse to perform a polymorphic operation if we would 5273 // not be able to read a notional 'vptr' value. 5274 APValue Val; 5275 This.moveInto(Val); 5276 QualType StarThisType = 5277 Info.Ctx.getLValueReferenceType(This.Designator.getType(Info.Ctx)); 5278 Info.FFDiag(E, diag::note_constexpr_polymorphic_unknown_dynamic_type) 5279 << AK << Val.getAsString(Info.Ctx, StarThisType); 5280 return false; 5281 } 5282 return true; 5283 } 5284 5285 CheckDynamicTypeHandler Handler{AK}; 5286 return Obj && findSubobject(Info, E, Obj, This.Designator, Handler); 5287 } 5288 5289 /// Check that the pointee of the 'this' pointer in a member function call is 5290 /// either within its lifetime or in its period of construction or destruction. 5291 static bool 5292 checkNonVirtualMemberCallThisPointer(EvalInfo &Info, const Expr *E, 5293 const LValue &This, 5294 const CXXMethodDecl *NamedMember) { 5295 return checkDynamicType( 5296 Info, E, This, 5297 isa<CXXDestructorDecl>(NamedMember) ? AK_Destroy : AK_MemberCall, false); 5298 } 5299 5300 struct DynamicType { 5301 /// The dynamic class type of the object. 5302 const CXXRecordDecl *Type; 5303 /// The corresponding path length in the lvalue. 5304 unsigned PathLength; 5305 }; 5306 5307 static const CXXRecordDecl *getBaseClassType(SubobjectDesignator &Designator, 5308 unsigned PathLength) { 5309 assert(PathLength >= Designator.MostDerivedPathLength && PathLength <= 5310 Designator.Entries.size() && "invalid path length"); 5311 return (PathLength == Designator.MostDerivedPathLength) 5312 ? Designator.MostDerivedType->getAsCXXRecordDecl() 5313 : getAsBaseClass(Designator.Entries[PathLength - 1]); 5314 } 5315 5316 /// Determine the dynamic type of an object. 5317 static Optional<DynamicType> ComputeDynamicType(EvalInfo &Info, const Expr *E, 5318 LValue &This, AccessKinds AK) { 5319 // If we don't have an lvalue denoting an object of class type, there is no 5320 // meaningful dynamic type. (We consider objects of non-class type to have no 5321 // dynamic type.) 5322 if (!checkDynamicType(Info, E, This, AK, true)) 5323 return None; 5324 5325 // Refuse to compute a dynamic type in the presence of virtual bases. This 5326 // shouldn't happen other than in constant-folding situations, since literal 5327 // types can't have virtual bases. 5328 // 5329 // Note that consumers of DynamicType assume that the type has no virtual 5330 // bases, and will need modifications if this restriction is relaxed. 5331 const CXXRecordDecl *Class = 5332 This.Designator.MostDerivedType->getAsCXXRecordDecl(); 5333 if (!Class || Class->getNumVBases()) { 5334 Info.FFDiag(E); 5335 return None; 5336 } 5337 5338 // FIXME: For very deep class hierarchies, it might be beneficial to use a 5339 // binary search here instead. But the overwhelmingly common case is that 5340 // we're not in the middle of a constructor, so it probably doesn't matter 5341 // in practice. 5342 ArrayRef<APValue::LValuePathEntry> Path = This.Designator.Entries; 5343 for (unsigned PathLength = This.Designator.MostDerivedPathLength; 5344 PathLength <= Path.size(); ++PathLength) { 5345 switch (Info.isEvaluatingCtorDtor(This.getLValueBase(), 5346 Path.slice(0, PathLength))) { 5347 case ConstructionPhase::Bases: 5348 case ConstructionPhase::DestroyingBases: 5349 // We're constructing or destroying a base class. This is not the dynamic 5350 // type. 5351 break; 5352 5353 case ConstructionPhase::None: 5354 case ConstructionPhase::AfterBases: 5355 case ConstructionPhase::AfterFields: 5356 case ConstructionPhase::Destroying: 5357 // We've finished constructing the base classes and not yet started 5358 // destroying them again, so this is the dynamic type. 5359 return DynamicType{getBaseClassType(This.Designator, PathLength), 5360 PathLength}; 5361 } 5362 } 5363 5364 // CWG issue 1517: we're constructing a base class of the object described by 5365 // 'This', so that object has not yet begun its period of construction and 5366 // any polymorphic operation on it results in undefined behavior. 5367 Info.FFDiag(E); 5368 return None; 5369 } 5370 5371 /// Perform virtual dispatch. 5372 static const CXXMethodDecl *HandleVirtualDispatch( 5373 EvalInfo &Info, const Expr *E, LValue &This, const CXXMethodDecl *Found, 5374 llvm::SmallVectorImpl<QualType> &CovariantAdjustmentPath) { 5375 Optional<DynamicType> DynType = ComputeDynamicType( 5376 Info, E, This, 5377 isa<CXXDestructorDecl>(Found) ? AK_Destroy : AK_MemberCall); 5378 if (!DynType) 5379 return nullptr; 5380 5381 // Find the final overrider. It must be declared in one of the classes on the 5382 // path from the dynamic type to the static type. 5383 // FIXME: If we ever allow literal types to have virtual base classes, that 5384 // won't be true. 5385 const CXXMethodDecl *Callee = Found; 5386 unsigned PathLength = DynType->PathLength; 5387 for (/**/; PathLength <= This.Designator.Entries.size(); ++PathLength) { 5388 const CXXRecordDecl *Class = getBaseClassType(This.Designator, PathLength); 5389 const CXXMethodDecl *Overrider = 5390 Found->getCorrespondingMethodDeclaredInClass(Class, false); 5391 if (Overrider) { 5392 Callee = Overrider; 5393 break; 5394 } 5395 } 5396 5397 // C++2a [class.abstract]p6: 5398 // the effect of making a virtual call to a pure virtual function [...] is 5399 // undefined 5400 if (Callee->isPure()) { 5401 Info.FFDiag(E, diag::note_constexpr_pure_virtual_call, 1) << Callee; 5402 Info.Note(Callee->getLocation(), diag::note_declared_at); 5403 return nullptr; 5404 } 5405 5406 // If necessary, walk the rest of the path to determine the sequence of 5407 // covariant adjustment steps to apply. 5408 if (!Info.Ctx.hasSameUnqualifiedType(Callee->getReturnType(), 5409 Found->getReturnType())) { 5410 CovariantAdjustmentPath.push_back(Callee->getReturnType()); 5411 for (unsigned CovariantPathLength = PathLength + 1; 5412 CovariantPathLength != This.Designator.Entries.size(); 5413 ++CovariantPathLength) { 5414 const CXXRecordDecl *NextClass = 5415 getBaseClassType(This.Designator, CovariantPathLength); 5416 const CXXMethodDecl *Next = 5417 Found->getCorrespondingMethodDeclaredInClass(NextClass, false); 5418 if (Next && !Info.Ctx.hasSameUnqualifiedType( 5419 Next->getReturnType(), CovariantAdjustmentPath.back())) 5420 CovariantAdjustmentPath.push_back(Next->getReturnType()); 5421 } 5422 if (!Info.Ctx.hasSameUnqualifiedType(Found->getReturnType(), 5423 CovariantAdjustmentPath.back())) 5424 CovariantAdjustmentPath.push_back(Found->getReturnType()); 5425 } 5426 5427 // Perform 'this' adjustment. 5428 if (!CastToDerivedClass(Info, E, This, Callee->getParent(), PathLength)) 5429 return nullptr; 5430 5431 return Callee; 5432 } 5433 5434 /// Perform the adjustment from a value returned by a virtual function to 5435 /// a value of the statically expected type, which may be a pointer or 5436 /// reference to a base class of the returned type. 5437 static bool HandleCovariantReturnAdjustment(EvalInfo &Info, const Expr *E, 5438 APValue &Result, 5439 ArrayRef<QualType> Path) { 5440 assert(Result.isLValue() && 5441 "unexpected kind of APValue for covariant return"); 5442 if (Result.isNullPointer()) 5443 return true; 5444 5445 LValue LVal; 5446 LVal.setFrom(Info.Ctx, Result); 5447 5448 const CXXRecordDecl *OldClass = Path[0]->getPointeeCXXRecordDecl(); 5449 for (unsigned I = 1; I != Path.size(); ++I) { 5450 const CXXRecordDecl *NewClass = Path[I]->getPointeeCXXRecordDecl(); 5451 assert(OldClass && NewClass && "unexpected kind of covariant return"); 5452 if (OldClass != NewClass && 5453 !CastToBaseClass(Info, E, LVal, OldClass, NewClass)) 5454 return false; 5455 OldClass = NewClass; 5456 } 5457 5458 LVal.moveInto(Result); 5459 return true; 5460 } 5461 5462 /// Determine whether \p Base, which is known to be a direct base class of 5463 /// \p Derived, is a public base class. 5464 static bool isBaseClassPublic(const CXXRecordDecl *Derived, 5465 const CXXRecordDecl *Base) { 5466 for (const CXXBaseSpecifier &BaseSpec : Derived->bases()) { 5467 auto *BaseClass = BaseSpec.getType()->getAsCXXRecordDecl(); 5468 if (BaseClass && declaresSameEntity(BaseClass, Base)) 5469 return BaseSpec.getAccessSpecifier() == AS_public; 5470 } 5471 llvm_unreachable("Base is not a direct base of Derived"); 5472 } 5473 5474 /// Apply the given dynamic cast operation on the provided lvalue. 5475 /// 5476 /// This implements the hard case of dynamic_cast, requiring a "runtime check" 5477 /// to find a suitable target subobject. 5478 static bool HandleDynamicCast(EvalInfo &Info, const ExplicitCastExpr *E, 5479 LValue &Ptr) { 5480 // We can't do anything with a non-symbolic pointer value. 5481 SubobjectDesignator &D = Ptr.Designator; 5482 if (D.Invalid) 5483 return false; 5484 5485 // C++ [expr.dynamic.cast]p6: 5486 // If v is a null pointer value, the result is a null pointer value. 5487 if (Ptr.isNullPointer() && !E->isGLValue()) 5488 return true; 5489 5490 // For all the other cases, we need the pointer to point to an object within 5491 // its lifetime / period of construction / destruction, and we need to know 5492 // its dynamic type. 5493 Optional<DynamicType> DynType = 5494 ComputeDynamicType(Info, E, Ptr, AK_DynamicCast); 5495 if (!DynType) 5496 return false; 5497 5498 // C++ [expr.dynamic.cast]p7: 5499 // If T is "pointer to cv void", then the result is a pointer to the most 5500 // derived object 5501 if (E->getType()->isVoidPointerType()) 5502 return CastToDerivedClass(Info, E, Ptr, DynType->Type, DynType->PathLength); 5503 5504 const CXXRecordDecl *C = E->getTypeAsWritten()->getPointeeCXXRecordDecl(); 5505 assert(C && "dynamic_cast target is not void pointer nor class"); 5506 CanQualType CQT = Info.Ctx.getCanonicalType(Info.Ctx.getRecordType(C)); 5507 5508 auto RuntimeCheckFailed = [&] (CXXBasePaths *Paths) { 5509 // C++ [expr.dynamic.cast]p9: 5510 if (!E->isGLValue()) { 5511 // The value of a failed cast to pointer type is the null pointer value 5512 // of the required result type. 5513 Ptr.setNull(Info.Ctx, E->getType()); 5514 return true; 5515 } 5516 5517 // A failed cast to reference type throws [...] std::bad_cast. 5518 unsigned DiagKind; 5519 if (!Paths && (declaresSameEntity(DynType->Type, C) || 5520 DynType->Type->isDerivedFrom(C))) 5521 DiagKind = 0; 5522 else if (!Paths || Paths->begin() == Paths->end()) 5523 DiagKind = 1; 5524 else if (Paths->isAmbiguous(CQT)) 5525 DiagKind = 2; 5526 else { 5527 assert(Paths->front().Access != AS_public && "why did the cast fail?"); 5528 DiagKind = 3; 5529 } 5530 Info.FFDiag(E, diag::note_constexpr_dynamic_cast_to_reference_failed) 5531 << DiagKind << Ptr.Designator.getType(Info.Ctx) 5532 << Info.Ctx.getRecordType(DynType->Type) 5533 << E->getType().getUnqualifiedType(); 5534 return false; 5535 }; 5536 5537 // Runtime check, phase 1: 5538 // Walk from the base subobject towards the derived object looking for the 5539 // target type. 5540 for (int PathLength = Ptr.Designator.Entries.size(); 5541 PathLength >= (int)DynType->PathLength; --PathLength) { 5542 const CXXRecordDecl *Class = getBaseClassType(Ptr.Designator, PathLength); 5543 if (declaresSameEntity(Class, C)) 5544 return CastToDerivedClass(Info, E, Ptr, Class, PathLength); 5545 // We can only walk across public inheritance edges. 5546 if (PathLength > (int)DynType->PathLength && 5547 !isBaseClassPublic(getBaseClassType(Ptr.Designator, PathLength - 1), 5548 Class)) 5549 return RuntimeCheckFailed(nullptr); 5550 } 5551 5552 // Runtime check, phase 2: 5553 // Search the dynamic type for an unambiguous public base of type C. 5554 CXXBasePaths Paths(/*FindAmbiguities=*/true, 5555 /*RecordPaths=*/true, /*DetectVirtual=*/false); 5556 if (DynType->Type->isDerivedFrom(C, Paths) && !Paths.isAmbiguous(CQT) && 5557 Paths.front().Access == AS_public) { 5558 // Downcast to the dynamic type... 5559 if (!CastToDerivedClass(Info, E, Ptr, DynType->Type, DynType->PathLength)) 5560 return false; 5561 // ... then upcast to the chosen base class subobject. 5562 for (CXXBasePathElement &Elem : Paths.front()) 5563 if (!HandleLValueBase(Info, E, Ptr, Elem.Class, Elem.Base)) 5564 return false; 5565 return true; 5566 } 5567 5568 // Otherwise, the runtime check fails. 5569 return RuntimeCheckFailed(&Paths); 5570 } 5571 5572 namespace { 5573 struct StartLifetimeOfUnionMemberHandler { 5574 EvalInfo &Info; 5575 const Expr *LHSExpr; 5576 const FieldDecl *Field; 5577 bool DuringInit; 5578 bool Failed = false; 5579 static const AccessKinds AccessKind = AK_Assign; 5580 5581 typedef bool result_type; 5582 bool failed() { return Failed; } 5583 bool found(APValue &Subobj, QualType SubobjType) { 5584 // We are supposed to perform no initialization but begin the lifetime of 5585 // the object. We interpret that as meaning to do what default 5586 // initialization of the object would do if all constructors involved were 5587 // trivial: 5588 // * All base, non-variant member, and array element subobjects' lifetimes 5589 // begin 5590 // * No variant members' lifetimes begin 5591 // * All scalar subobjects whose lifetimes begin have indeterminate values 5592 assert(SubobjType->isUnionType()); 5593 if (declaresSameEntity(Subobj.getUnionField(), Field)) { 5594 // This union member is already active. If it's also in-lifetime, there's 5595 // nothing to do. 5596 if (Subobj.getUnionValue().hasValue()) 5597 return true; 5598 } else if (DuringInit) { 5599 // We're currently in the process of initializing a different union 5600 // member. If we carried on, that initialization would attempt to 5601 // store to an inactive union member, resulting in undefined behavior. 5602 Info.FFDiag(LHSExpr, 5603 diag::note_constexpr_union_member_change_during_init); 5604 return false; 5605 } 5606 APValue Result; 5607 Failed = !getDefaultInitValue(Field->getType(), Result); 5608 Subobj.setUnion(Field, Result); 5609 return true; 5610 } 5611 bool found(APSInt &Value, QualType SubobjType) { 5612 llvm_unreachable("wrong value kind for union object"); 5613 } 5614 bool found(APFloat &Value, QualType SubobjType) { 5615 llvm_unreachable("wrong value kind for union object"); 5616 } 5617 }; 5618 } // end anonymous namespace 5619 5620 const AccessKinds StartLifetimeOfUnionMemberHandler::AccessKind; 5621 5622 /// Handle a builtin simple-assignment or a call to a trivial assignment 5623 /// operator whose left-hand side might involve a union member access. If it 5624 /// does, implicitly start the lifetime of any accessed union elements per 5625 /// C++20 [class.union]5. 5626 static bool HandleUnionActiveMemberChange(EvalInfo &Info, const Expr *LHSExpr, 5627 const LValue &LHS) { 5628 if (LHS.InvalidBase || LHS.Designator.Invalid) 5629 return false; 5630 5631 llvm::SmallVector<std::pair<unsigned, const FieldDecl*>, 4> UnionPathLengths; 5632 // C++ [class.union]p5: 5633 // define the set S(E) of subexpressions of E as follows: 5634 unsigned PathLength = LHS.Designator.Entries.size(); 5635 for (const Expr *E = LHSExpr; E != nullptr;) { 5636 // -- If E is of the form A.B, S(E) contains the elements of S(A)... 5637 if (auto *ME = dyn_cast<MemberExpr>(E)) { 5638 auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl()); 5639 // Note that we can't implicitly start the lifetime of a reference, 5640 // so we don't need to proceed any further if we reach one. 5641 if (!FD || FD->getType()->isReferenceType()) 5642 break; 5643 5644 // ... and also contains A.B if B names a union member ... 5645 if (FD->getParent()->isUnion()) { 5646 // ... of a non-class, non-array type, or of a class type with a 5647 // trivial default constructor that is not deleted, or an array of 5648 // such types. 5649 auto *RD = 5650 FD->getType()->getBaseElementTypeUnsafe()->getAsCXXRecordDecl(); 5651 if (!RD || RD->hasTrivialDefaultConstructor()) 5652 UnionPathLengths.push_back({PathLength - 1, FD}); 5653 } 5654 5655 E = ME->getBase(); 5656 --PathLength; 5657 assert(declaresSameEntity(FD, 5658 LHS.Designator.Entries[PathLength] 5659 .getAsBaseOrMember().getPointer())); 5660 5661 // -- If E is of the form A[B] and is interpreted as a built-in array 5662 // subscripting operator, S(E) is [S(the array operand, if any)]. 5663 } else if (auto *ASE = dyn_cast<ArraySubscriptExpr>(E)) { 5664 // Step over an ArrayToPointerDecay implicit cast. 5665 auto *Base = ASE->getBase()->IgnoreImplicit(); 5666 if (!Base->getType()->isArrayType()) 5667 break; 5668 5669 E = Base; 5670 --PathLength; 5671 5672 } else if (auto *ICE = dyn_cast<ImplicitCastExpr>(E)) { 5673 // Step over a derived-to-base conversion. 5674 E = ICE->getSubExpr(); 5675 if (ICE->getCastKind() == CK_NoOp) 5676 continue; 5677 if (ICE->getCastKind() != CK_DerivedToBase && 5678 ICE->getCastKind() != CK_UncheckedDerivedToBase) 5679 break; 5680 // Walk path backwards as we walk up from the base to the derived class. 5681 for (const CXXBaseSpecifier *Elt : llvm::reverse(ICE->path())) { 5682 --PathLength; 5683 (void)Elt; 5684 assert(declaresSameEntity(Elt->getType()->getAsCXXRecordDecl(), 5685 LHS.Designator.Entries[PathLength] 5686 .getAsBaseOrMember().getPointer())); 5687 } 5688 5689 // -- Otherwise, S(E) is empty. 5690 } else { 5691 break; 5692 } 5693 } 5694 5695 // Common case: no unions' lifetimes are started. 5696 if (UnionPathLengths.empty()) 5697 return true; 5698 5699 // if modification of X [would access an inactive union member], an object 5700 // of the type of X is implicitly created 5701 CompleteObject Obj = 5702 findCompleteObject(Info, LHSExpr, AK_Assign, LHS, LHSExpr->getType()); 5703 if (!Obj) 5704 return false; 5705 for (std::pair<unsigned, const FieldDecl *> LengthAndField : 5706 llvm::reverse(UnionPathLengths)) { 5707 // Form a designator for the union object. 5708 SubobjectDesignator D = LHS.Designator; 5709 D.truncate(Info.Ctx, LHS.Base, LengthAndField.first); 5710 5711 bool DuringInit = Info.isEvaluatingCtorDtor(LHS.Base, D.Entries) == 5712 ConstructionPhase::AfterBases; 5713 StartLifetimeOfUnionMemberHandler StartLifetime{ 5714 Info, LHSExpr, LengthAndField.second, DuringInit}; 5715 if (!findSubobject(Info, LHSExpr, Obj, D, StartLifetime)) 5716 return false; 5717 } 5718 5719 return true; 5720 } 5721 5722 namespace { 5723 typedef SmallVector<APValue, 8> ArgVector; 5724 } 5725 5726 /// EvaluateArgs - Evaluate the arguments to a function call. 5727 static bool EvaluateArgs(ArrayRef<const Expr *> Args, ArgVector &ArgValues, 5728 EvalInfo &Info, const FunctionDecl *Callee) { 5729 bool Success = true; 5730 llvm::SmallBitVector ForbiddenNullArgs; 5731 if (Callee->hasAttr<NonNullAttr>()) { 5732 ForbiddenNullArgs.resize(Args.size()); 5733 for (const auto *Attr : Callee->specific_attrs<NonNullAttr>()) { 5734 if (!Attr->args_size()) { 5735 ForbiddenNullArgs.set(); 5736 break; 5737 } else 5738 for (auto Idx : Attr->args()) { 5739 unsigned ASTIdx = Idx.getASTIndex(); 5740 if (ASTIdx >= Args.size()) 5741 continue; 5742 ForbiddenNullArgs[ASTIdx] = 1; 5743 } 5744 } 5745 } 5746 // FIXME: This is the wrong evaluation order for an assignment operator 5747 // called via operator syntax. 5748 for (unsigned Idx = 0; Idx < Args.size(); Idx++) { 5749 if (!Evaluate(ArgValues[Idx], Info, Args[Idx])) { 5750 // If we're checking for a potential constant expression, evaluate all 5751 // initializers even if some of them fail. 5752 if (!Info.noteFailure()) 5753 return false; 5754 Success = false; 5755 } else if (!ForbiddenNullArgs.empty() && 5756 ForbiddenNullArgs[Idx] && 5757 ArgValues[Idx].isLValue() && 5758 ArgValues[Idx].isNullPointer()) { 5759 Info.CCEDiag(Args[Idx], diag::note_non_null_attribute_failed); 5760 if (!Info.noteFailure()) 5761 return false; 5762 Success = false; 5763 } 5764 } 5765 return Success; 5766 } 5767 5768 /// Evaluate a function call. 5769 static bool HandleFunctionCall(SourceLocation CallLoc, 5770 const FunctionDecl *Callee, const LValue *This, 5771 ArrayRef<const Expr*> Args, const Stmt *Body, 5772 EvalInfo &Info, APValue &Result, 5773 const LValue *ResultSlot) { 5774 ArgVector ArgValues(Args.size()); 5775 if (!EvaluateArgs(Args, ArgValues, Info, Callee)) 5776 return false; 5777 5778 if (!Info.CheckCallLimit(CallLoc)) 5779 return false; 5780 5781 CallStackFrame Frame(Info, CallLoc, Callee, This, ArgValues.data()); 5782 5783 // For a trivial copy or move assignment, perform an APValue copy. This is 5784 // essential for unions, where the operations performed by the assignment 5785 // operator cannot be represented as statements. 5786 // 5787 // Skip this for non-union classes with no fields; in that case, the defaulted 5788 // copy/move does not actually read the object. 5789 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Callee); 5790 if (MD && MD->isDefaulted() && 5791 (MD->getParent()->isUnion() || 5792 (MD->isTrivial() && 5793 isReadByLvalueToRvalueConversion(MD->getParent())))) { 5794 assert(This && 5795 (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator())); 5796 LValue RHS; 5797 RHS.setFrom(Info.Ctx, ArgValues[0]); 5798 APValue RHSValue; 5799 if (!handleLValueToRValueConversion(Info, Args[0], Args[0]->getType(), RHS, 5800 RHSValue, MD->getParent()->isUnion())) 5801 return false; 5802 if (Info.getLangOpts().CPlusPlus20 && MD->isTrivial() && 5803 !HandleUnionActiveMemberChange(Info, Args[0], *This)) 5804 return false; 5805 if (!handleAssignment(Info, Args[0], *This, MD->getThisType(), 5806 RHSValue)) 5807 return false; 5808 This->moveInto(Result); 5809 return true; 5810 } else if (MD && isLambdaCallOperator(MD)) { 5811 // We're in a lambda; determine the lambda capture field maps unless we're 5812 // just constexpr checking a lambda's call operator. constexpr checking is 5813 // done before the captures have been added to the closure object (unless 5814 // we're inferring constexpr-ness), so we don't have access to them in this 5815 // case. But since we don't need the captures to constexpr check, we can 5816 // just ignore them. 5817 if (!Info.checkingPotentialConstantExpression()) 5818 MD->getParent()->getCaptureFields(Frame.LambdaCaptureFields, 5819 Frame.LambdaThisCaptureField); 5820 } 5821 5822 StmtResult Ret = {Result, ResultSlot}; 5823 EvalStmtResult ESR = EvaluateStmt(Ret, Info, Body); 5824 if (ESR == ESR_Succeeded) { 5825 if (Callee->getReturnType()->isVoidType()) 5826 return true; 5827 Info.FFDiag(Callee->getEndLoc(), diag::note_constexpr_no_return); 5828 } 5829 return ESR == ESR_Returned; 5830 } 5831 5832 /// Evaluate a constructor call. 5833 static bool HandleConstructorCall(const Expr *E, const LValue &This, 5834 APValue *ArgValues, 5835 const CXXConstructorDecl *Definition, 5836 EvalInfo &Info, APValue &Result) { 5837 SourceLocation CallLoc = E->getExprLoc(); 5838 if (!Info.CheckCallLimit(CallLoc)) 5839 return false; 5840 5841 const CXXRecordDecl *RD = Definition->getParent(); 5842 if (RD->getNumVBases()) { 5843 Info.FFDiag(CallLoc, diag::note_constexpr_virtual_base) << RD; 5844 return false; 5845 } 5846 5847 EvalInfo::EvaluatingConstructorRAII EvalObj( 5848 Info, 5849 ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries}, 5850 RD->getNumBases()); 5851 CallStackFrame Frame(Info, CallLoc, Definition, &This, ArgValues); 5852 5853 // FIXME: Creating an APValue just to hold a nonexistent return value is 5854 // wasteful. 5855 APValue RetVal; 5856 StmtResult Ret = {RetVal, nullptr}; 5857 5858 // If it's a delegating constructor, delegate. 5859 if (Definition->isDelegatingConstructor()) { 5860 CXXConstructorDecl::init_const_iterator I = Definition->init_begin(); 5861 { 5862 FullExpressionRAII InitScope(Info); 5863 if (!EvaluateInPlace(Result, Info, This, (*I)->getInit()) || 5864 !InitScope.destroy()) 5865 return false; 5866 } 5867 return EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed; 5868 } 5869 5870 // For a trivial copy or move constructor, perform an APValue copy. This is 5871 // essential for unions (or classes with anonymous union members), where the 5872 // operations performed by the constructor cannot be represented by 5873 // ctor-initializers. 5874 // 5875 // Skip this for empty non-union classes; we should not perform an 5876 // lvalue-to-rvalue conversion on them because their copy constructor does not 5877 // actually read them. 5878 if (Definition->isDefaulted() && Definition->isCopyOrMoveConstructor() && 5879 (Definition->getParent()->isUnion() || 5880 (Definition->isTrivial() && 5881 isReadByLvalueToRvalueConversion(Definition->getParent())))) { 5882 LValue RHS; 5883 RHS.setFrom(Info.Ctx, ArgValues[0]); 5884 return handleLValueToRValueConversion( 5885 Info, E, Definition->getParamDecl(0)->getType().getNonReferenceType(), 5886 RHS, Result, Definition->getParent()->isUnion()); 5887 } 5888 5889 // Reserve space for the struct members. 5890 if (!Result.hasValue()) { 5891 if (!RD->isUnion()) 5892 Result = APValue(APValue::UninitStruct(), RD->getNumBases(), 5893 std::distance(RD->field_begin(), RD->field_end())); 5894 else 5895 // A union starts with no active member. 5896 Result = APValue((const FieldDecl*)nullptr); 5897 } 5898 5899 if (RD->isInvalidDecl()) return false; 5900 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); 5901 5902 // A scope for temporaries lifetime-extended by reference members. 5903 BlockScopeRAII LifetimeExtendedScope(Info); 5904 5905 bool Success = true; 5906 unsigned BasesSeen = 0; 5907 #ifndef NDEBUG 5908 CXXRecordDecl::base_class_const_iterator BaseIt = RD->bases_begin(); 5909 #endif 5910 CXXRecordDecl::field_iterator FieldIt = RD->field_begin(); 5911 auto SkipToField = [&](FieldDecl *FD, bool Indirect) { 5912 // We might be initializing the same field again if this is an indirect 5913 // field initialization. 5914 if (FieldIt == RD->field_end() || 5915 FieldIt->getFieldIndex() > FD->getFieldIndex()) { 5916 assert(Indirect && "fields out of order?"); 5917 return; 5918 } 5919 5920 // Default-initialize any fields with no explicit initializer. 5921 for (; !declaresSameEntity(*FieldIt, FD); ++FieldIt) { 5922 assert(FieldIt != RD->field_end() && "missing field?"); 5923 if (!FieldIt->isUnnamedBitfield()) 5924 Success &= getDefaultInitValue( 5925 FieldIt->getType(), 5926 Result.getStructField(FieldIt->getFieldIndex())); 5927 } 5928 ++FieldIt; 5929 }; 5930 for (const auto *I : Definition->inits()) { 5931 LValue Subobject = This; 5932 LValue SubobjectParent = This; 5933 APValue *Value = &Result; 5934 5935 // Determine the subobject to initialize. 5936 FieldDecl *FD = nullptr; 5937 if (I->isBaseInitializer()) { 5938 QualType BaseType(I->getBaseClass(), 0); 5939 #ifndef NDEBUG 5940 // Non-virtual base classes are initialized in the order in the class 5941 // definition. We have already checked for virtual base classes. 5942 assert(!BaseIt->isVirtual() && "virtual base for literal type"); 5943 assert(Info.Ctx.hasSameType(BaseIt->getType(), BaseType) && 5944 "base class initializers not in expected order"); 5945 ++BaseIt; 5946 #endif 5947 if (!HandleLValueDirectBase(Info, I->getInit(), Subobject, RD, 5948 BaseType->getAsCXXRecordDecl(), &Layout)) 5949 return false; 5950 Value = &Result.getStructBase(BasesSeen++); 5951 } else if ((FD = I->getMember())) { 5952 if (!HandleLValueMember(Info, I->getInit(), Subobject, FD, &Layout)) 5953 return false; 5954 if (RD->isUnion()) { 5955 Result = APValue(FD); 5956 Value = &Result.getUnionValue(); 5957 } else { 5958 SkipToField(FD, false); 5959 Value = &Result.getStructField(FD->getFieldIndex()); 5960 } 5961 } else if (IndirectFieldDecl *IFD = I->getIndirectMember()) { 5962 // Walk the indirect field decl's chain to find the object to initialize, 5963 // and make sure we've initialized every step along it. 5964 auto IndirectFieldChain = IFD->chain(); 5965 for (auto *C : IndirectFieldChain) { 5966 FD = cast<FieldDecl>(C); 5967 CXXRecordDecl *CD = cast<CXXRecordDecl>(FD->getParent()); 5968 // Switch the union field if it differs. This happens if we had 5969 // preceding zero-initialization, and we're now initializing a union 5970 // subobject other than the first. 5971 // FIXME: In this case, the values of the other subobjects are 5972 // specified, since zero-initialization sets all padding bits to zero. 5973 if (!Value->hasValue() || 5974 (Value->isUnion() && Value->getUnionField() != FD)) { 5975 if (CD->isUnion()) 5976 *Value = APValue(FD); 5977 else 5978 // FIXME: This immediately starts the lifetime of all members of 5979 // an anonymous struct. It would be preferable to strictly start 5980 // member lifetime in initialization order. 5981 Success &= getDefaultInitValue(Info.Ctx.getRecordType(CD), *Value); 5982 } 5983 // Store Subobject as its parent before updating it for the last element 5984 // in the chain. 5985 if (C == IndirectFieldChain.back()) 5986 SubobjectParent = Subobject; 5987 if (!HandleLValueMember(Info, I->getInit(), Subobject, FD)) 5988 return false; 5989 if (CD->isUnion()) 5990 Value = &Value->getUnionValue(); 5991 else { 5992 if (C == IndirectFieldChain.front() && !RD->isUnion()) 5993 SkipToField(FD, true); 5994 Value = &Value->getStructField(FD->getFieldIndex()); 5995 } 5996 } 5997 } else { 5998 llvm_unreachable("unknown base initializer kind"); 5999 } 6000 6001 // Need to override This for implicit field initializers as in this case 6002 // This refers to innermost anonymous struct/union containing initializer, 6003 // not to currently constructed class. 6004 const Expr *Init = I->getInit(); 6005 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &SubobjectParent, 6006 isa<CXXDefaultInitExpr>(Init)); 6007 FullExpressionRAII InitScope(Info); 6008 if (!EvaluateInPlace(*Value, Info, Subobject, Init) || 6009 (FD && FD->isBitField() && 6010 !truncateBitfieldValue(Info, Init, *Value, FD))) { 6011 // If we're checking for a potential constant expression, evaluate all 6012 // initializers even if some of them fail. 6013 if (!Info.noteFailure()) 6014 return false; 6015 Success = false; 6016 } 6017 6018 // This is the point at which the dynamic type of the object becomes this 6019 // class type. 6020 if (I->isBaseInitializer() && BasesSeen == RD->getNumBases()) 6021 EvalObj.finishedConstructingBases(); 6022 } 6023 6024 // Default-initialize any remaining fields. 6025 if (!RD->isUnion()) { 6026 for (; FieldIt != RD->field_end(); ++FieldIt) { 6027 if (!FieldIt->isUnnamedBitfield()) 6028 Success &= getDefaultInitValue( 6029 FieldIt->getType(), 6030 Result.getStructField(FieldIt->getFieldIndex())); 6031 } 6032 } 6033 6034 EvalObj.finishedConstructingFields(); 6035 6036 return Success && 6037 EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed && 6038 LifetimeExtendedScope.destroy(); 6039 } 6040 6041 static bool HandleConstructorCall(const Expr *E, const LValue &This, 6042 ArrayRef<const Expr*> Args, 6043 const CXXConstructorDecl *Definition, 6044 EvalInfo &Info, APValue &Result) { 6045 ArgVector ArgValues(Args.size()); 6046 if (!EvaluateArgs(Args, ArgValues, Info, Definition)) 6047 return false; 6048 6049 return HandleConstructorCall(E, This, ArgValues.data(), Definition, 6050 Info, Result); 6051 } 6052 6053 static bool HandleDestructionImpl(EvalInfo &Info, SourceLocation CallLoc, 6054 const LValue &This, APValue &Value, 6055 QualType T) { 6056 // Objects can only be destroyed while they're within their lifetimes. 6057 // FIXME: We have no representation for whether an object of type nullptr_t 6058 // is in its lifetime; it usually doesn't matter. Perhaps we should model it 6059 // as indeterminate instead? 6060 if (Value.isAbsent() && !T->isNullPtrType()) { 6061 APValue Printable; 6062 This.moveInto(Printable); 6063 Info.FFDiag(CallLoc, diag::note_constexpr_destroy_out_of_lifetime) 6064 << Printable.getAsString(Info.Ctx, Info.Ctx.getLValueReferenceType(T)); 6065 return false; 6066 } 6067 6068 // Invent an expression for location purposes. 6069 // FIXME: We shouldn't need to do this. 6070 OpaqueValueExpr LocE(CallLoc, Info.Ctx.IntTy, VK_RValue); 6071 6072 // For arrays, destroy elements right-to-left. 6073 if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(T)) { 6074 uint64_t Size = CAT->getSize().getZExtValue(); 6075 QualType ElemT = CAT->getElementType(); 6076 6077 LValue ElemLV = This; 6078 ElemLV.addArray(Info, &LocE, CAT); 6079 if (!HandleLValueArrayAdjustment(Info, &LocE, ElemLV, ElemT, Size)) 6080 return false; 6081 6082 // Ensure that we have actual array elements available to destroy; the 6083 // destructors might mutate the value, so we can't run them on the array 6084 // filler. 6085 if (Size && Size > Value.getArrayInitializedElts()) 6086 expandArray(Value, Value.getArraySize() - 1); 6087 6088 for (; Size != 0; --Size) { 6089 APValue &Elem = Value.getArrayInitializedElt(Size - 1); 6090 if (!HandleLValueArrayAdjustment(Info, &LocE, ElemLV, ElemT, -1) || 6091 !HandleDestructionImpl(Info, CallLoc, ElemLV, Elem, ElemT)) 6092 return false; 6093 } 6094 6095 // End the lifetime of this array now. 6096 Value = APValue(); 6097 return true; 6098 } 6099 6100 const CXXRecordDecl *RD = T->getAsCXXRecordDecl(); 6101 if (!RD) { 6102 if (T.isDestructedType()) { 6103 Info.FFDiag(CallLoc, diag::note_constexpr_unsupported_destruction) << T; 6104 return false; 6105 } 6106 6107 Value = APValue(); 6108 return true; 6109 } 6110 6111 if (RD->getNumVBases()) { 6112 Info.FFDiag(CallLoc, diag::note_constexpr_virtual_base) << RD; 6113 return false; 6114 } 6115 6116 const CXXDestructorDecl *DD = RD->getDestructor(); 6117 if (!DD && !RD->hasTrivialDestructor()) { 6118 Info.FFDiag(CallLoc); 6119 return false; 6120 } 6121 6122 if (!DD || DD->isTrivial() || 6123 (RD->isAnonymousStructOrUnion() && RD->isUnion())) { 6124 // A trivial destructor just ends the lifetime of the object. Check for 6125 // this case before checking for a body, because we might not bother 6126 // building a body for a trivial destructor. Note that it doesn't matter 6127 // whether the destructor is constexpr in this case; all trivial 6128 // destructors are constexpr. 6129 // 6130 // If an anonymous union would be destroyed, some enclosing destructor must 6131 // have been explicitly defined, and the anonymous union destruction should 6132 // have no effect. 6133 Value = APValue(); 6134 return true; 6135 } 6136 6137 if (!Info.CheckCallLimit(CallLoc)) 6138 return false; 6139 6140 const FunctionDecl *Definition = nullptr; 6141 const Stmt *Body = DD->getBody(Definition); 6142 6143 if (!CheckConstexprFunction(Info, CallLoc, DD, Definition, Body)) 6144 return false; 6145 6146 CallStackFrame Frame(Info, CallLoc, Definition, &This, nullptr); 6147 6148 // We're now in the period of destruction of this object. 6149 unsigned BasesLeft = RD->getNumBases(); 6150 EvalInfo::EvaluatingDestructorRAII EvalObj( 6151 Info, 6152 ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries}); 6153 if (!EvalObj.DidInsert) { 6154 // C++2a [class.dtor]p19: 6155 // the behavior is undefined if the destructor is invoked for an object 6156 // whose lifetime has ended 6157 // (Note that formally the lifetime ends when the period of destruction 6158 // begins, even though certain uses of the object remain valid until the 6159 // period of destruction ends.) 6160 Info.FFDiag(CallLoc, diag::note_constexpr_double_destroy); 6161 return false; 6162 } 6163 6164 // FIXME: Creating an APValue just to hold a nonexistent return value is 6165 // wasteful. 6166 APValue RetVal; 6167 StmtResult Ret = {RetVal, nullptr}; 6168 if (EvaluateStmt(Ret, Info, Definition->getBody()) == ESR_Failed) 6169 return false; 6170 6171 // A union destructor does not implicitly destroy its members. 6172 if (RD->isUnion()) 6173 return true; 6174 6175 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); 6176 6177 // We don't have a good way to iterate fields in reverse, so collect all the 6178 // fields first and then walk them backwards. 6179 SmallVector<FieldDecl*, 16> Fields(RD->field_begin(), RD->field_end()); 6180 for (const FieldDecl *FD : llvm::reverse(Fields)) { 6181 if (FD->isUnnamedBitfield()) 6182 continue; 6183 6184 LValue Subobject = This; 6185 if (!HandleLValueMember(Info, &LocE, Subobject, FD, &Layout)) 6186 return false; 6187 6188 APValue *SubobjectValue = &Value.getStructField(FD->getFieldIndex()); 6189 if (!HandleDestructionImpl(Info, CallLoc, Subobject, *SubobjectValue, 6190 FD->getType())) 6191 return false; 6192 } 6193 6194 if (BasesLeft != 0) 6195 EvalObj.startedDestroyingBases(); 6196 6197 // Destroy base classes in reverse order. 6198 for (const CXXBaseSpecifier &Base : llvm::reverse(RD->bases())) { 6199 --BasesLeft; 6200 6201 QualType BaseType = Base.getType(); 6202 LValue Subobject = This; 6203 if (!HandleLValueDirectBase(Info, &LocE, Subobject, RD, 6204 BaseType->getAsCXXRecordDecl(), &Layout)) 6205 return false; 6206 6207 APValue *SubobjectValue = &Value.getStructBase(BasesLeft); 6208 if (!HandleDestructionImpl(Info, CallLoc, Subobject, *SubobjectValue, 6209 BaseType)) 6210 return false; 6211 } 6212 assert(BasesLeft == 0 && "NumBases was wrong?"); 6213 6214 // The period of destruction ends now. The object is gone. 6215 Value = APValue(); 6216 return true; 6217 } 6218 6219 namespace { 6220 struct DestroyObjectHandler { 6221 EvalInfo &Info; 6222 const Expr *E; 6223 const LValue &This; 6224 const AccessKinds AccessKind; 6225 6226 typedef bool result_type; 6227 bool failed() { return false; } 6228 bool found(APValue &Subobj, QualType SubobjType) { 6229 return HandleDestructionImpl(Info, E->getExprLoc(), This, Subobj, 6230 SubobjType); 6231 } 6232 bool found(APSInt &Value, QualType SubobjType) { 6233 Info.FFDiag(E, diag::note_constexpr_destroy_complex_elem); 6234 return false; 6235 } 6236 bool found(APFloat &Value, QualType SubobjType) { 6237 Info.FFDiag(E, diag::note_constexpr_destroy_complex_elem); 6238 return false; 6239 } 6240 }; 6241 } 6242 6243 /// Perform a destructor or pseudo-destructor call on the given object, which 6244 /// might in general not be a complete object. 6245 static bool HandleDestruction(EvalInfo &Info, const Expr *E, 6246 const LValue &This, QualType ThisType) { 6247 CompleteObject Obj = findCompleteObject(Info, E, AK_Destroy, This, ThisType); 6248 DestroyObjectHandler Handler = {Info, E, This, AK_Destroy}; 6249 return Obj && findSubobject(Info, E, Obj, This.Designator, Handler); 6250 } 6251 6252 /// Destroy and end the lifetime of the given complete object. 6253 static bool HandleDestruction(EvalInfo &Info, SourceLocation Loc, 6254 APValue::LValueBase LVBase, APValue &Value, 6255 QualType T) { 6256 // If we've had an unmodeled side-effect, we can't rely on mutable state 6257 // (such as the object we're about to destroy) being correct. 6258 if (Info.EvalStatus.HasSideEffects) 6259 return false; 6260 6261 LValue LV; 6262 LV.set({LVBase}); 6263 return HandleDestructionImpl(Info, Loc, LV, Value, T); 6264 } 6265 6266 /// Perform a call to 'perator new' or to `__builtin_operator_new'. 6267 static bool HandleOperatorNewCall(EvalInfo &Info, const CallExpr *E, 6268 LValue &Result) { 6269 if (Info.checkingPotentialConstantExpression() || 6270 Info.SpeculativeEvaluationDepth) 6271 return false; 6272 6273 // This is permitted only within a call to std::allocator<T>::allocate. 6274 auto Caller = Info.getStdAllocatorCaller("allocate"); 6275 if (!Caller) { 6276 Info.FFDiag(E->getExprLoc(), Info.getLangOpts().CPlusPlus20 6277 ? diag::note_constexpr_new_untyped 6278 : diag::note_constexpr_new); 6279 return false; 6280 } 6281 6282 QualType ElemType = Caller.ElemType; 6283 if (ElemType->isIncompleteType() || ElemType->isFunctionType()) { 6284 Info.FFDiag(E->getExprLoc(), 6285 diag::note_constexpr_new_not_complete_object_type) 6286 << (ElemType->isIncompleteType() ? 0 : 1) << ElemType; 6287 return false; 6288 } 6289 6290 APSInt ByteSize; 6291 if (!EvaluateInteger(E->getArg(0), ByteSize, Info)) 6292 return false; 6293 bool IsNothrow = false; 6294 for (unsigned I = 1, N = E->getNumArgs(); I != N; ++I) { 6295 EvaluateIgnoredValue(Info, E->getArg(I)); 6296 IsNothrow |= E->getType()->isNothrowT(); 6297 } 6298 6299 CharUnits ElemSize; 6300 if (!HandleSizeof(Info, E->getExprLoc(), ElemType, ElemSize)) 6301 return false; 6302 APInt Size, Remainder; 6303 APInt ElemSizeAP(ByteSize.getBitWidth(), ElemSize.getQuantity()); 6304 APInt::udivrem(ByteSize, ElemSizeAP, Size, Remainder); 6305 if (Remainder != 0) { 6306 // This likely indicates a bug in the implementation of 'std::allocator'. 6307 Info.FFDiag(E->getExprLoc(), diag::note_constexpr_operator_new_bad_size) 6308 << ByteSize << APSInt(ElemSizeAP, true) << ElemType; 6309 return false; 6310 } 6311 6312 if (ByteSize.getActiveBits() > ConstantArrayType::getMaxSizeBits(Info.Ctx)) { 6313 if (IsNothrow) { 6314 Result.setNull(Info.Ctx, E->getType()); 6315 return true; 6316 } 6317 6318 Info.FFDiag(E, diag::note_constexpr_new_too_large) << APSInt(Size, true); 6319 return false; 6320 } 6321 6322 QualType AllocType = Info.Ctx.getConstantArrayType(ElemType, Size, nullptr, 6323 ArrayType::Normal, 0); 6324 APValue *Val = Info.createHeapAlloc(E, AllocType, Result); 6325 *Val = APValue(APValue::UninitArray(), 0, Size.getZExtValue()); 6326 Result.addArray(Info, E, cast<ConstantArrayType>(AllocType)); 6327 return true; 6328 } 6329 6330 static bool hasVirtualDestructor(QualType T) { 6331 if (CXXRecordDecl *RD = T->getAsCXXRecordDecl()) 6332 if (CXXDestructorDecl *DD = RD->getDestructor()) 6333 return DD->isVirtual(); 6334 return false; 6335 } 6336 6337 static const FunctionDecl *getVirtualOperatorDelete(QualType T) { 6338 if (CXXRecordDecl *RD = T->getAsCXXRecordDecl()) 6339 if (CXXDestructorDecl *DD = RD->getDestructor()) 6340 return DD->isVirtual() ? DD->getOperatorDelete() : nullptr; 6341 return nullptr; 6342 } 6343 6344 /// Check that the given object is a suitable pointer to a heap allocation that 6345 /// still exists and is of the right kind for the purpose of a deletion. 6346 /// 6347 /// On success, returns the heap allocation to deallocate. On failure, produces 6348 /// a diagnostic and returns None. 6349 static Optional<DynAlloc *> CheckDeleteKind(EvalInfo &Info, const Expr *E, 6350 const LValue &Pointer, 6351 DynAlloc::Kind DeallocKind) { 6352 auto PointerAsString = [&] { 6353 return Pointer.toString(Info.Ctx, Info.Ctx.VoidPtrTy); 6354 }; 6355 6356 DynamicAllocLValue DA = Pointer.Base.dyn_cast<DynamicAllocLValue>(); 6357 if (!DA) { 6358 Info.FFDiag(E, diag::note_constexpr_delete_not_heap_alloc) 6359 << PointerAsString(); 6360 if (Pointer.Base) 6361 NoteLValueLocation(Info, Pointer.Base); 6362 return None; 6363 } 6364 6365 Optional<DynAlloc *> Alloc = Info.lookupDynamicAlloc(DA); 6366 if (!Alloc) { 6367 Info.FFDiag(E, diag::note_constexpr_double_delete); 6368 return None; 6369 } 6370 6371 QualType AllocType = Pointer.Base.getDynamicAllocType(); 6372 if (DeallocKind != (*Alloc)->getKind()) { 6373 Info.FFDiag(E, diag::note_constexpr_new_delete_mismatch) 6374 << DeallocKind << (*Alloc)->getKind() << AllocType; 6375 NoteLValueLocation(Info, Pointer.Base); 6376 return None; 6377 } 6378 6379 bool Subobject = false; 6380 if (DeallocKind == DynAlloc::New) { 6381 Subobject = Pointer.Designator.MostDerivedPathLength != 0 || 6382 Pointer.Designator.isOnePastTheEnd(); 6383 } else { 6384 Subobject = Pointer.Designator.Entries.size() != 1 || 6385 Pointer.Designator.Entries[0].getAsArrayIndex() != 0; 6386 } 6387 if (Subobject) { 6388 Info.FFDiag(E, diag::note_constexpr_delete_subobject) 6389 << PointerAsString() << Pointer.Designator.isOnePastTheEnd(); 6390 return None; 6391 } 6392 6393 return Alloc; 6394 } 6395 6396 // Perform a call to 'operator delete' or '__builtin_operator_delete'. 6397 bool HandleOperatorDeleteCall(EvalInfo &Info, const CallExpr *E) { 6398 if (Info.checkingPotentialConstantExpression() || 6399 Info.SpeculativeEvaluationDepth) 6400 return false; 6401 6402 // This is permitted only within a call to std::allocator<T>::deallocate. 6403 if (!Info.getStdAllocatorCaller("deallocate")) { 6404 Info.FFDiag(E->getExprLoc()); 6405 return true; 6406 } 6407 6408 LValue Pointer; 6409 if (!EvaluatePointer(E->getArg(0), Pointer, Info)) 6410 return false; 6411 for (unsigned I = 1, N = E->getNumArgs(); I != N; ++I) 6412 EvaluateIgnoredValue(Info, E->getArg(I)); 6413 6414 if (Pointer.Designator.Invalid) 6415 return false; 6416 6417 // Deleting a null pointer has no effect. 6418 if (Pointer.isNullPointer()) 6419 return true; 6420 6421 if (!CheckDeleteKind(Info, E, Pointer, DynAlloc::StdAllocator)) 6422 return false; 6423 6424 Info.HeapAllocs.erase(Pointer.Base.get<DynamicAllocLValue>()); 6425 return true; 6426 } 6427 6428 //===----------------------------------------------------------------------===// 6429 // Generic Evaluation 6430 //===----------------------------------------------------------------------===// 6431 namespace { 6432 6433 class BitCastBuffer { 6434 // FIXME: We're going to need bit-level granularity when we support 6435 // bit-fields. 6436 // FIXME: Its possible under the C++ standard for 'char' to not be 8 bits, but 6437 // we don't support a host or target where that is the case. Still, we should 6438 // use a more generic type in case we ever do. 6439 SmallVector<Optional<unsigned char>, 32> Bytes; 6440 6441 static_assert(std::numeric_limits<unsigned char>::digits >= 8, 6442 "Need at least 8 bit unsigned char"); 6443 6444 bool TargetIsLittleEndian; 6445 6446 public: 6447 BitCastBuffer(CharUnits Width, bool TargetIsLittleEndian) 6448 : Bytes(Width.getQuantity()), 6449 TargetIsLittleEndian(TargetIsLittleEndian) {} 6450 6451 LLVM_NODISCARD 6452 bool readObject(CharUnits Offset, CharUnits Width, 6453 SmallVectorImpl<unsigned char> &Output) const { 6454 for (CharUnits I = Offset, E = Offset + Width; I != E; ++I) { 6455 // If a byte of an integer is uninitialized, then the whole integer is 6456 // uninitalized. 6457 if (!Bytes[I.getQuantity()]) 6458 return false; 6459 Output.push_back(*Bytes[I.getQuantity()]); 6460 } 6461 if (llvm::sys::IsLittleEndianHost != TargetIsLittleEndian) 6462 std::reverse(Output.begin(), Output.end()); 6463 return true; 6464 } 6465 6466 void writeObject(CharUnits Offset, SmallVectorImpl<unsigned char> &Input) { 6467 if (llvm::sys::IsLittleEndianHost != TargetIsLittleEndian) 6468 std::reverse(Input.begin(), Input.end()); 6469 6470 size_t Index = 0; 6471 for (unsigned char Byte : Input) { 6472 assert(!Bytes[Offset.getQuantity() + Index] && "overwriting a byte?"); 6473 Bytes[Offset.getQuantity() + Index] = Byte; 6474 ++Index; 6475 } 6476 } 6477 6478 size_t size() { return Bytes.size(); } 6479 }; 6480 6481 /// Traverse an APValue to produce an BitCastBuffer, emulating how the current 6482 /// target would represent the value at runtime. 6483 class APValueToBufferConverter { 6484 EvalInfo &Info; 6485 BitCastBuffer Buffer; 6486 const CastExpr *BCE; 6487 6488 APValueToBufferConverter(EvalInfo &Info, CharUnits ObjectWidth, 6489 const CastExpr *BCE) 6490 : Info(Info), 6491 Buffer(ObjectWidth, Info.Ctx.getTargetInfo().isLittleEndian()), 6492 BCE(BCE) {} 6493 6494 bool visit(const APValue &Val, QualType Ty) { 6495 return visit(Val, Ty, CharUnits::fromQuantity(0)); 6496 } 6497 6498 // Write out Val with type Ty into Buffer starting at Offset. 6499 bool visit(const APValue &Val, QualType Ty, CharUnits Offset) { 6500 assert((size_t)Offset.getQuantity() <= Buffer.size()); 6501 6502 // As a special case, nullptr_t has an indeterminate value. 6503 if (Ty->isNullPtrType()) 6504 return true; 6505 6506 // Dig through Src to find the byte at SrcOffset. 6507 switch (Val.getKind()) { 6508 case APValue::Indeterminate: 6509 case APValue::None: 6510 return true; 6511 6512 case APValue::Int: 6513 return visitInt(Val.getInt(), Ty, Offset); 6514 case APValue::Float: 6515 return visitFloat(Val.getFloat(), Ty, Offset); 6516 case APValue::Array: 6517 return visitArray(Val, Ty, Offset); 6518 case APValue::Struct: 6519 return visitRecord(Val, Ty, Offset); 6520 6521 case APValue::ComplexInt: 6522 case APValue::ComplexFloat: 6523 case APValue::Vector: 6524 case APValue::FixedPoint: 6525 // FIXME: We should support these. 6526 6527 case APValue::Union: 6528 case APValue::MemberPointer: 6529 case APValue::AddrLabelDiff: { 6530 Info.FFDiag(BCE->getBeginLoc(), 6531 diag::note_constexpr_bit_cast_unsupported_type) 6532 << Ty; 6533 return false; 6534 } 6535 6536 case APValue::LValue: 6537 llvm_unreachable("LValue subobject in bit_cast?"); 6538 } 6539 llvm_unreachable("Unhandled APValue::ValueKind"); 6540 } 6541 6542 bool visitRecord(const APValue &Val, QualType Ty, CharUnits Offset) { 6543 const RecordDecl *RD = Ty->getAsRecordDecl(); 6544 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); 6545 6546 // Visit the base classes. 6547 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) { 6548 for (size_t I = 0, E = CXXRD->getNumBases(); I != E; ++I) { 6549 const CXXBaseSpecifier &BS = CXXRD->bases_begin()[I]; 6550 CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl(); 6551 6552 if (!visitRecord(Val.getStructBase(I), BS.getType(), 6553 Layout.getBaseClassOffset(BaseDecl) + Offset)) 6554 return false; 6555 } 6556 } 6557 6558 // Visit the fields. 6559 unsigned FieldIdx = 0; 6560 for (FieldDecl *FD : RD->fields()) { 6561 if (FD->isBitField()) { 6562 Info.FFDiag(BCE->getBeginLoc(), 6563 diag::note_constexpr_bit_cast_unsupported_bitfield); 6564 return false; 6565 } 6566 6567 uint64_t FieldOffsetBits = Layout.getFieldOffset(FieldIdx); 6568 6569 assert(FieldOffsetBits % Info.Ctx.getCharWidth() == 0 && 6570 "only bit-fields can have sub-char alignment"); 6571 CharUnits FieldOffset = 6572 Info.Ctx.toCharUnitsFromBits(FieldOffsetBits) + Offset; 6573 QualType FieldTy = FD->getType(); 6574 if (!visit(Val.getStructField(FieldIdx), FieldTy, FieldOffset)) 6575 return false; 6576 ++FieldIdx; 6577 } 6578 6579 return true; 6580 } 6581 6582 bool visitArray(const APValue &Val, QualType Ty, CharUnits Offset) { 6583 const auto *CAT = 6584 dyn_cast_or_null<ConstantArrayType>(Ty->getAsArrayTypeUnsafe()); 6585 if (!CAT) 6586 return false; 6587 6588 CharUnits ElemWidth = Info.Ctx.getTypeSizeInChars(CAT->getElementType()); 6589 unsigned NumInitializedElts = Val.getArrayInitializedElts(); 6590 unsigned ArraySize = Val.getArraySize(); 6591 // First, initialize the initialized elements. 6592 for (unsigned I = 0; I != NumInitializedElts; ++I) { 6593 const APValue &SubObj = Val.getArrayInitializedElt(I); 6594 if (!visit(SubObj, CAT->getElementType(), Offset + I * ElemWidth)) 6595 return false; 6596 } 6597 6598 // Next, initialize the rest of the array using the filler. 6599 if (Val.hasArrayFiller()) { 6600 const APValue &Filler = Val.getArrayFiller(); 6601 for (unsigned I = NumInitializedElts; I != ArraySize; ++I) { 6602 if (!visit(Filler, CAT->getElementType(), Offset + I * ElemWidth)) 6603 return false; 6604 } 6605 } 6606 6607 return true; 6608 } 6609 6610 bool visitInt(const APSInt &Val, QualType Ty, CharUnits Offset) { 6611 CharUnits Width = Info.Ctx.getTypeSizeInChars(Ty); 6612 SmallVector<unsigned char, 8> Bytes(Width.getQuantity()); 6613 llvm::StoreIntToMemory(Val, &*Bytes.begin(), Width.getQuantity()); 6614 Buffer.writeObject(Offset, Bytes); 6615 return true; 6616 } 6617 6618 bool visitFloat(const APFloat &Val, QualType Ty, CharUnits Offset) { 6619 APSInt AsInt(Val.bitcastToAPInt()); 6620 return visitInt(AsInt, Ty, Offset); 6621 } 6622 6623 public: 6624 static Optional<BitCastBuffer> convert(EvalInfo &Info, const APValue &Src, 6625 const CastExpr *BCE) { 6626 CharUnits DstSize = Info.Ctx.getTypeSizeInChars(BCE->getType()); 6627 APValueToBufferConverter Converter(Info, DstSize, BCE); 6628 if (!Converter.visit(Src, BCE->getSubExpr()->getType())) 6629 return None; 6630 return Converter.Buffer; 6631 } 6632 }; 6633 6634 /// Write an BitCastBuffer into an APValue. 6635 class BufferToAPValueConverter { 6636 EvalInfo &Info; 6637 const BitCastBuffer &Buffer; 6638 const CastExpr *BCE; 6639 6640 BufferToAPValueConverter(EvalInfo &Info, const BitCastBuffer &Buffer, 6641 const CastExpr *BCE) 6642 : Info(Info), Buffer(Buffer), BCE(BCE) {} 6643 6644 // Emit an unsupported bit_cast type error. Sema refuses to build a bit_cast 6645 // with an invalid type, so anything left is a deficiency on our part (FIXME). 6646 // Ideally this will be unreachable. 6647 llvm::NoneType unsupportedType(QualType Ty) { 6648 Info.FFDiag(BCE->getBeginLoc(), 6649 diag::note_constexpr_bit_cast_unsupported_type) 6650 << Ty; 6651 return None; 6652 } 6653 6654 Optional<APValue> visit(const BuiltinType *T, CharUnits Offset, 6655 const EnumType *EnumSugar = nullptr) { 6656 if (T->isNullPtrType()) { 6657 uint64_t NullValue = Info.Ctx.getTargetNullPointerValue(QualType(T, 0)); 6658 return APValue((Expr *)nullptr, 6659 /*Offset=*/CharUnits::fromQuantity(NullValue), 6660 APValue::NoLValuePath{}, /*IsNullPtr=*/true); 6661 } 6662 6663 CharUnits SizeOf = Info.Ctx.getTypeSizeInChars(T); 6664 SmallVector<uint8_t, 8> Bytes; 6665 if (!Buffer.readObject(Offset, SizeOf, Bytes)) { 6666 // If this is std::byte or unsigned char, then its okay to store an 6667 // indeterminate value. 6668 bool IsStdByte = EnumSugar && EnumSugar->isStdByteType(); 6669 bool IsUChar = 6670 !EnumSugar && (T->isSpecificBuiltinType(BuiltinType::UChar) || 6671 T->isSpecificBuiltinType(BuiltinType::Char_U)); 6672 if (!IsStdByte && !IsUChar) { 6673 QualType DisplayType(EnumSugar ? (const Type *)EnumSugar : T, 0); 6674 Info.FFDiag(BCE->getExprLoc(), 6675 diag::note_constexpr_bit_cast_indet_dest) 6676 << DisplayType << Info.Ctx.getLangOpts().CharIsSigned; 6677 return None; 6678 } 6679 6680 return APValue::IndeterminateValue(); 6681 } 6682 6683 APSInt Val(SizeOf.getQuantity() * Info.Ctx.getCharWidth(), true); 6684 llvm::LoadIntFromMemory(Val, &*Bytes.begin(), Bytes.size()); 6685 6686 if (T->isIntegralOrEnumerationType()) { 6687 Val.setIsSigned(T->isSignedIntegerOrEnumerationType()); 6688 return APValue(Val); 6689 } 6690 6691 if (T->isRealFloatingType()) { 6692 const llvm::fltSemantics &Semantics = 6693 Info.Ctx.getFloatTypeSemantics(QualType(T, 0)); 6694 return APValue(APFloat(Semantics, Val)); 6695 } 6696 6697 return unsupportedType(QualType(T, 0)); 6698 } 6699 6700 Optional<APValue> visit(const RecordType *RTy, CharUnits Offset) { 6701 const RecordDecl *RD = RTy->getAsRecordDecl(); 6702 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); 6703 6704 unsigned NumBases = 0; 6705 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) 6706 NumBases = CXXRD->getNumBases(); 6707 6708 APValue ResultVal(APValue::UninitStruct(), NumBases, 6709 std::distance(RD->field_begin(), RD->field_end())); 6710 6711 // Visit the base classes. 6712 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) { 6713 for (size_t I = 0, E = CXXRD->getNumBases(); I != E; ++I) { 6714 const CXXBaseSpecifier &BS = CXXRD->bases_begin()[I]; 6715 CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl(); 6716 if (BaseDecl->isEmpty() || 6717 Info.Ctx.getASTRecordLayout(BaseDecl).getNonVirtualSize().isZero()) 6718 continue; 6719 6720 Optional<APValue> SubObj = visitType( 6721 BS.getType(), Layout.getBaseClassOffset(BaseDecl) + Offset); 6722 if (!SubObj) 6723 return None; 6724 ResultVal.getStructBase(I) = *SubObj; 6725 } 6726 } 6727 6728 // Visit the fields. 6729 unsigned FieldIdx = 0; 6730 for (FieldDecl *FD : RD->fields()) { 6731 // FIXME: We don't currently support bit-fields. A lot of the logic for 6732 // this is in CodeGen, so we need to factor it around. 6733 if (FD->isBitField()) { 6734 Info.FFDiag(BCE->getBeginLoc(), 6735 diag::note_constexpr_bit_cast_unsupported_bitfield); 6736 return None; 6737 } 6738 6739 uint64_t FieldOffsetBits = Layout.getFieldOffset(FieldIdx); 6740 assert(FieldOffsetBits % Info.Ctx.getCharWidth() == 0); 6741 6742 CharUnits FieldOffset = 6743 CharUnits::fromQuantity(FieldOffsetBits / Info.Ctx.getCharWidth()) + 6744 Offset; 6745 QualType FieldTy = FD->getType(); 6746 Optional<APValue> SubObj = visitType(FieldTy, FieldOffset); 6747 if (!SubObj) 6748 return None; 6749 ResultVal.getStructField(FieldIdx) = *SubObj; 6750 ++FieldIdx; 6751 } 6752 6753 return ResultVal; 6754 } 6755 6756 Optional<APValue> visit(const EnumType *Ty, CharUnits Offset) { 6757 QualType RepresentationType = Ty->getDecl()->getIntegerType(); 6758 assert(!RepresentationType.isNull() && 6759 "enum forward decl should be caught by Sema"); 6760 const auto *AsBuiltin = 6761 RepresentationType.getCanonicalType()->castAs<BuiltinType>(); 6762 // Recurse into the underlying type. Treat std::byte transparently as 6763 // unsigned char. 6764 return visit(AsBuiltin, Offset, /*EnumTy=*/Ty); 6765 } 6766 6767 Optional<APValue> visit(const ConstantArrayType *Ty, CharUnits Offset) { 6768 size_t Size = Ty->getSize().getLimitedValue(); 6769 CharUnits ElementWidth = Info.Ctx.getTypeSizeInChars(Ty->getElementType()); 6770 6771 APValue ArrayValue(APValue::UninitArray(), Size, Size); 6772 for (size_t I = 0; I != Size; ++I) { 6773 Optional<APValue> ElementValue = 6774 visitType(Ty->getElementType(), Offset + I * ElementWidth); 6775 if (!ElementValue) 6776 return None; 6777 ArrayValue.getArrayInitializedElt(I) = std::move(*ElementValue); 6778 } 6779 6780 return ArrayValue; 6781 } 6782 6783 Optional<APValue> visit(const Type *Ty, CharUnits Offset) { 6784 return unsupportedType(QualType(Ty, 0)); 6785 } 6786 6787 Optional<APValue> visitType(QualType Ty, CharUnits Offset) { 6788 QualType Can = Ty.getCanonicalType(); 6789 6790 switch (Can->getTypeClass()) { 6791 #define TYPE(Class, Base) \ 6792 case Type::Class: \ 6793 return visit(cast<Class##Type>(Can.getTypePtr()), Offset); 6794 #define ABSTRACT_TYPE(Class, Base) 6795 #define NON_CANONICAL_TYPE(Class, Base) \ 6796 case Type::Class: \ 6797 llvm_unreachable("non-canonical type should be impossible!"); 6798 #define DEPENDENT_TYPE(Class, Base) \ 6799 case Type::Class: \ 6800 llvm_unreachable( \ 6801 "dependent types aren't supported in the constant evaluator!"); 6802 #define NON_CANONICAL_UNLESS_DEPENDENT(Class, Base) \ 6803 case Type::Class: \ 6804 llvm_unreachable("either dependent or not canonical!"); 6805 #include "clang/AST/TypeNodes.inc" 6806 } 6807 llvm_unreachable("Unhandled Type::TypeClass"); 6808 } 6809 6810 public: 6811 // Pull out a full value of type DstType. 6812 static Optional<APValue> convert(EvalInfo &Info, BitCastBuffer &Buffer, 6813 const CastExpr *BCE) { 6814 BufferToAPValueConverter Converter(Info, Buffer, BCE); 6815 return Converter.visitType(BCE->getType(), CharUnits::fromQuantity(0)); 6816 } 6817 }; 6818 6819 static bool checkBitCastConstexprEligibilityType(SourceLocation Loc, 6820 QualType Ty, EvalInfo *Info, 6821 const ASTContext &Ctx, 6822 bool CheckingDest) { 6823 Ty = Ty.getCanonicalType(); 6824 6825 auto diag = [&](int Reason) { 6826 if (Info) 6827 Info->FFDiag(Loc, diag::note_constexpr_bit_cast_invalid_type) 6828 << CheckingDest << (Reason == 4) << Reason; 6829 return false; 6830 }; 6831 auto note = [&](int Construct, QualType NoteTy, SourceLocation NoteLoc) { 6832 if (Info) 6833 Info->Note(NoteLoc, diag::note_constexpr_bit_cast_invalid_subtype) 6834 << NoteTy << Construct << Ty; 6835 return false; 6836 }; 6837 6838 if (Ty->isUnionType()) 6839 return diag(0); 6840 if (Ty->isPointerType()) 6841 return diag(1); 6842 if (Ty->isMemberPointerType()) 6843 return diag(2); 6844 if (Ty.isVolatileQualified()) 6845 return diag(3); 6846 6847 if (RecordDecl *Record = Ty->getAsRecordDecl()) { 6848 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(Record)) { 6849 for (CXXBaseSpecifier &BS : CXXRD->bases()) 6850 if (!checkBitCastConstexprEligibilityType(Loc, BS.getType(), Info, Ctx, 6851 CheckingDest)) 6852 return note(1, BS.getType(), BS.getBeginLoc()); 6853 } 6854 for (FieldDecl *FD : Record->fields()) { 6855 if (FD->getType()->isReferenceType()) 6856 return diag(4); 6857 if (!checkBitCastConstexprEligibilityType(Loc, FD->getType(), Info, Ctx, 6858 CheckingDest)) 6859 return note(0, FD->getType(), FD->getBeginLoc()); 6860 } 6861 } 6862 6863 if (Ty->isArrayType() && 6864 !checkBitCastConstexprEligibilityType(Loc, Ctx.getBaseElementType(Ty), 6865 Info, Ctx, CheckingDest)) 6866 return false; 6867 6868 return true; 6869 } 6870 6871 static bool checkBitCastConstexprEligibility(EvalInfo *Info, 6872 const ASTContext &Ctx, 6873 const CastExpr *BCE) { 6874 bool DestOK = checkBitCastConstexprEligibilityType( 6875 BCE->getBeginLoc(), BCE->getType(), Info, Ctx, true); 6876 bool SourceOK = DestOK && checkBitCastConstexprEligibilityType( 6877 BCE->getBeginLoc(), 6878 BCE->getSubExpr()->getType(), Info, Ctx, false); 6879 return SourceOK; 6880 } 6881 6882 static bool handleLValueToRValueBitCast(EvalInfo &Info, APValue &DestValue, 6883 APValue &SourceValue, 6884 const CastExpr *BCE) { 6885 assert(CHAR_BIT == 8 && Info.Ctx.getTargetInfo().getCharWidth() == 8 && 6886 "no host or target supports non 8-bit chars"); 6887 assert(SourceValue.isLValue() && 6888 "LValueToRValueBitcast requires an lvalue operand!"); 6889 6890 if (!checkBitCastConstexprEligibility(&Info, Info.Ctx, BCE)) 6891 return false; 6892 6893 LValue SourceLValue; 6894 APValue SourceRValue; 6895 SourceLValue.setFrom(Info.Ctx, SourceValue); 6896 if (!handleLValueToRValueConversion( 6897 Info, BCE, BCE->getSubExpr()->getType().withConst(), SourceLValue, 6898 SourceRValue, /*WantObjectRepresentation=*/true)) 6899 return false; 6900 6901 // Read out SourceValue into a char buffer. 6902 Optional<BitCastBuffer> Buffer = 6903 APValueToBufferConverter::convert(Info, SourceRValue, BCE); 6904 if (!Buffer) 6905 return false; 6906 6907 // Write out the buffer into a new APValue. 6908 Optional<APValue> MaybeDestValue = 6909 BufferToAPValueConverter::convert(Info, *Buffer, BCE); 6910 if (!MaybeDestValue) 6911 return false; 6912 6913 DestValue = std::move(*MaybeDestValue); 6914 return true; 6915 } 6916 6917 template <class Derived> 6918 class ExprEvaluatorBase 6919 : public ConstStmtVisitor<Derived, bool> { 6920 private: 6921 Derived &getDerived() { return static_cast<Derived&>(*this); } 6922 bool DerivedSuccess(const APValue &V, const Expr *E) { 6923 return getDerived().Success(V, E); 6924 } 6925 bool DerivedZeroInitialization(const Expr *E) { 6926 return getDerived().ZeroInitialization(E); 6927 } 6928 6929 // Check whether a conditional operator with a non-constant condition is a 6930 // potential constant expression. If neither arm is a potential constant 6931 // expression, then the conditional operator is not either. 6932 template<typename ConditionalOperator> 6933 void CheckPotentialConstantConditional(const ConditionalOperator *E) { 6934 assert(Info.checkingPotentialConstantExpression()); 6935 6936 // Speculatively evaluate both arms. 6937 SmallVector<PartialDiagnosticAt, 8> Diag; 6938 { 6939 SpeculativeEvaluationRAII Speculate(Info, &Diag); 6940 StmtVisitorTy::Visit(E->getFalseExpr()); 6941 if (Diag.empty()) 6942 return; 6943 } 6944 6945 { 6946 SpeculativeEvaluationRAII Speculate(Info, &Diag); 6947 Diag.clear(); 6948 StmtVisitorTy::Visit(E->getTrueExpr()); 6949 if (Diag.empty()) 6950 return; 6951 } 6952 6953 Error(E, diag::note_constexpr_conditional_never_const); 6954 } 6955 6956 6957 template<typename ConditionalOperator> 6958 bool HandleConditionalOperator(const ConditionalOperator *E) { 6959 bool BoolResult; 6960 if (!EvaluateAsBooleanCondition(E->getCond(), BoolResult, Info)) { 6961 if (Info.checkingPotentialConstantExpression() && Info.noteFailure()) { 6962 CheckPotentialConstantConditional(E); 6963 return false; 6964 } 6965 if (Info.noteFailure()) { 6966 StmtVisitorTy::Visit(E->getTrueExpr()); 6967 StmtVisitorTy::Visit(E->getFalseExpr()); 6968 } 6969 return false; 6970 } 6971 6972 Expr *EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr(); 6973 return StmtVisitorTy::Visit(EvalExpr); 6974 } 6975 6976 protected: 6977 EvalInfo &Info; 6978 typedef ConstStmtVisitor<Derived, bool> StmtVisitorTy; 6979 typedef ExprEvaluatorBase ExprEvaluatorBaseTy; 6980 6981 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) { 6982 return Info.CCEDiag(E, D); 6983 } 6984 6985 bool ZeroInitialization(const Expr *E) { return Error(E); } 6986 6987 public: 6988 ExprEvaluatorBase(EvalInfo &Info) : Info(Info) {} 6989 6990 EvalInfo &getEvalInfo() { return Info; } 6991 6992 /// Report an evaluation error. This should only be called when an error is 6993 /// first discovered. When propagating an error, just return false. 6994 bool Error(const Expr *E, diag::kind D) { 6995 Info.FFDiag(E, D); 6996 return false; 6997 } 6998 bool Error(const Expr *E) { 6999 return Error(E, diag::note_invalid_subexpr_in_const_expr); 7000 } 7001 7002 bool VisitStmt(const Stmt *) { 7003 llvm_unreachable("Expression evaluator should not be called on stmts"); 7004 } 7005 bool VisitExpr(const Expr *E) { 7006 return Error(E); 7007 } 7008 7009 bool VisitConstantExpr(const ConstantExpr *E) { 7010 if (E->hasAPValueResult()) 7011 return DerivedSuccess(E->getAPValueResult(), E); 7012 7013 return StmtVisitorTy::Visit(E->getSubExpr()); 7014 } 7015 7016 bool VisitParenExpr(const ParenExpr *E) 7017 { return StmtVisitorTy::Visit(E->getSubExpr()); } 7018 bool VisitUnaryExtension(const UnaryOperator *E) 7019 { return StmtVisitorTy::Visit(E->getSubExpr()); } 7020 bool VisitUnaryPlus(const UnaryOperator *E) 7021 { return StmtVisitorTy::Visit(E->getSubExpr()); } 7022 bool VisitChooseExpr(const ChooseExpr *E) 7023 { return StmtVisitorTy::Visit(E->getChosenSubExpr()); } 7024 bool VisitGenericSelectionExpr(const GenericSelectionExpr *E) 7025 { return StmtVisitorTy::Visit(E->getResultExpr()); } 7026 bool VisitSubstNonTypeTemplateParmExpr(const SubstNonTypeTemplateParmExpr *E) 7027 { return StmtVisitorTy::Visit(E->getReplacement()); } 7028 bool VisitCXXDefaultArgExpr(const CXXDefaultArgExpr *E) { 7029 TempVersionRAII RAII(*Info.CurrentCall); 7030 SourceLocExprScopeGuard Guard(E, Info.CurrentCall->CurSourceLocExprScope); 7031 return StmtVisitorTy::Visit(E->getExpr()); 7032 } 7033 bool VisitCXXDefaultInitExpr(const CXXDefaultInitExpr *E) { 7034 TempVersionRAII RAII(*Info.CurrentCall); 7035 // The initializer may not have been parsed yet, or might be erroneous. 7036 if (!E->getExpr()) 7037 return Error(E); 7038 SourceLocExprScopeGuard Guard(E, Info.CurrentCall->CurSourceLocExprScope); 7039 return StmtVisitorTy::Visit(E->getExpr()); 7040 } 7041 7042 bool VisitExprWithCleanups(const ExprWithCleanups *E) { 7043 FullExpressionRAII Scope(Info); 7044 return StmtVisitorTy::Visit(E->getSubExpr()) && Scope.destroy(); 7045 } 7046 7047 // Temporaries are registered when created, so we don't care about 7048 // CXXBindTemporaryExpr. 7049 bool VisitCXXBindTemporaryExpr(const CXXBindTemporaryExpr *E) { 7050 return StmtVisitorTy::Visit(E->getSubExpr()); 7051 } 7052 7053 bool VisitCXXReinterpretCastExpr(const CXXReinterpretCastExpr *E) { 7054 CCEDiag(E, diag::note_constexpr_invalid_cast) << 0; 7055 return static_cast<Derived*>(this)->VisitCastExpr(E); 7056 } 7057 bool VisitCXXDynamicCastExpr(const CXXDynamicCastExpr *E) { 7058 if (!Info.Ctx.getLangOpts().CPlusPlus20) 7059 CCEDiag(E, diag::note_constexpr_invalid_cast) << 1; 7060 return static_cast<Derived*>(this)->VisitCastExpr(E); 7061 } 7062 bool VisitBuiltinBitCastExpr(const BuiltinBitCastExpr *E) { 7063 return static_cast<Derived*>(this)->VisitCastExpr(E); 7064 } 7065 7066 bool VisitBinaryOperator(const BinaryOperator *E) { 7067 switch (E->getOpcode()) { 7068 default: 7069 return Error(E); 7070 7071 case BO_Comma: 7072 VisitIgnoredValue(E->getLHS()); 7073 return StmtVisitorTy::Visit(E->getRHS()); 7074 7075 case BO_PtrMemD: 7076 case BO_PtrMemI: { 7077 LValue Obj; 7078 if (!HandleMemberPointerAccess(Info, E, Obj)) 7079 return false; 7080 APValue Result; 7081 if (!handleLValueToRValueConversion(Info, E, E->getType(), Obj, Result)) 7082 return false; 7083 return DerivedSuccess(Result, E); 7084 } 7085 } 7086 } 7087 7088 bool VisitCXXRewrittenBinaryOperator(const CXXRewrittenBinaryOperator *E) { 7089 return StmtVisitorTy::Visit(E->getSemanticForm()); 7090 } 7091 7092 bool VisitBinaryConditionalOperator(const BinaryConditionalOperator *E) { 7093 // Evaluate and cache the common expression. We treat it as a temporary, 7094 // even though it's not quite the same thing. 7095 LValue CommonLV; 7096 if (!Evaluate(Info.CurrentCall->createTemporary( 7097 E->getOpaqueValue(), 7098 getStorageType(Info.Ctx, E->getOpaqueValue()), false, 7099 CommonLV), 7100 Info, E->getCommon())) 7101 return false; 7102 7103 return HandleConditionalOperator(E); 7104 } 7105 7106 bool VisitConditionalOperator(const ConditionalOperator *E) { 7107 bool IsBcpCall = false; 7108 // If the condition (ignoring parens) is a __builtin_constant_p call, 7109 // the result is a constant expression if it can be folded without 7110 // side-effects. This is an important GNU extension. See GCC PR38377 7111 // for discussion. 7112 if (const CallExpr *CallCE = 7113 dyn_cast<CallExpr>(E->getCond()->IgnoreParenCasts())) 7114 if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p) 7115 IsBcpCall = true; 7116 7117 // Always assume __builtin_constant_p(...) ? ... : ... is a potential 7118 // constant expression; we can't check whether it's potentially foldable. 7119 // FIXME: We should instead treat __builtin_constant_p as non-constant if 7120 // it would return 'false' in this mode. 7121 if (Info.checkingPotentialConstantExpression() && IsBcpCall) 7122 return false; 7123 7124 FoldConstant Fold(Info, IsBcpCall); 7125 if (!HandleConditionalOperator(E)) { 7126 Fold.keepDiagnostics(); 7127 return false; 7128 } 7129 7130 return true; 7131 } 7132 7133 bool VisitOpaqueValueExpr(const OpaqueValueExpr *E) { 7134 if (APValue *Value = Info.CurrentCall->getCurrentTemporary(E)) 7135 return DerivedSuccess(*Value, E); 7136 7137 const Expr *Source = E->getSourceExpr(); 7138 if (!Source) 7139 return Error(E); 7140 if (Source == E) { // sanity checking. 7141 assert(0 && "OpaqueValueExpr recursively refers to itself"); 7142 return Error(E); 7143 } 7144 return StmtVisitorTy::Visit(Source); 7145 } 7146 7147 bool VisitPseudoObjectExpr(const PseudoObjectExpr *E) { 7148 for (const Expr *SemE : E->semantics()) { 7149 if (auto *OVE = dyn_cast<OpaqueValueExpr>(SemE)) { 7150 // FIXME: We can't handle the case where an OpaqueValueExpr is also the 7151 // result expression: there could be two different LValues that would 7152 // refer to the same object in that case, and we can't model that. 7153 if (SemE == E->getResultExpr()) 7154 return Error(E); 7155 7156 // Unique OVEs get evaluated if and when we encounter them when 7157 // emitting the rest of the semantic form, rather than eagerly. 7158 if (OVE->isUnique()) 7159 continue; 7160 7161 LValue LV; 7162 if (!Evaluate(Info.CurrentCall->createTemporary( 7163 OVE, getStorageType(Info.Ctx, OVE), false, LV), 7164 Info, OVE->getSourceExpr())) 7165 return false; 7166 } else if (SemE == E->getResultExpr()) { 7167 if (!StmtVisitorTy::Visit(SemE)) 7168 return false; 7169 } else { 7170 if (!EvaluateIgnoredValue(Info, SemE)) 7171 return false; 7172 } 7173 } 7174 return true; 7175 } 7176 7177 bool VisitCallExpr(const CallExpr *E) { 7178 APValue Result; 7179 if (!handleCallExpr(E, Result, nullptr)) 7180 return false; 7181 return DerivedSuccess(Result, E); 7182 } 7183 7184 bool handleCallExpr(const CallExpr *E, APValue &Result, 7185 const LValue *ResultSlot) { 7186 const Expr *Callee = E->getCallee()->IgnoreParens(); 7187 QualType CalleeType = Callee->getType(); 7188 7189 const FunctionDecl *FD = nullptr; 7190 LValue *This = nullptr, ThisVal; 7191 auto Args = llvm::makeArrayRef(E->getArgs(), E->getNumArgs()); 7192 bool HasQualifier = false; 7193 7194 // Extract function decl and 'this' pointer from the callee. 7195 if (CalleeType->isSpecificBuiltinType(BuiltinType::BoundMember)) { 7196 const CXXMethodDecl *Member = nullptr; 7197 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Callee)) { 7198 // Explicit bound member calls, such as x.f() or p->g(); 7199 if (!EvaluateObjectArgument(Info, ME->getBase(), ThisVal)) 7200 return false; 7201 Member = dyn_cast<CXXMethodDecl>(ME->getMemberDecl()); 7202 if (!Member) 7203 return Error(Callee); 7204 This = &ThisVal; 7205 HasQualifier = ME->hasQualifier(); 7206 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(Callee)) { 7207 // Indirect bound member calls ('.*' or '->*'). 7208 const ValueDecl *D = 7209 HandleMemberPointerAccess(Info, BE, ThisVal, false); 7210 if (!D) 7211 return false; 7212 Member = dyn_cast<CXXMethodDecl>(D); 7213 if (!Member) 7214 return Error(Callee); 7215 This = &ThisVal; 7216 } else if (const auto *PDE = dyn_cast<CXXPseudoDestructorExpr>(Callee)) { 7217 if (!Info.getLangOpts().CPlusPlus20) 7218 Info.CCEDiag(PDE, diag::note_constexpr_pseudo_destructor); 7219 return EvaluateObjectArgument(Info, PDE->getBase(), ThisVal) && 7220 HandleDestruction(Info, PDE, ThisVal, PDE->getDestroyedType()); 7221 } else 7222 return Error(Callee); 7223 FD = Member; 7224 } else if (CalleeType->isFunctionPointerType()) { 7225 LValue Call; 7226 if (!EvaluatePointer(Callee, Call, Info)) 7227 return false; 7228 7229 if (!Call.getLValueOffset().isZero()) 7230 return Error(Callee); 7231 FD = dyn_cast_or_null<FunctionDecl>( 7232 Call.getLValueBase().dyn_cast<const ValueDecl*>()); 7233 if (!FD) 7234 return Error(Callee); 7235 // Don't call function pointers which have been cast to some other type. 7236 // Per DR (no number yet), the caller and callee can differ in noexcept. 7237 if (!Info.Ctx.hasSameFunctionTypeIgnoringExceptionSpec( 7238 CalleeType->getPointeeType(), FD->getType())) { 7239 return Error(E); 7240 } 7241 7242 // Overloaded operator calls to member functions are represented as normal 7243 // calls with '*this' as the first argument. 7244 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD); 7245 if (MD && !MD->isStatic()) { 7246 // FIXME: When selecting an implicit conversion for an overloaded 7247 // operator delete, we sometimes try to evaluate calls to conversion 7248 // operators without a 'this' parameter! 7249 if (Args.empty()) 7250 return Error(E); 7251 7252 if (!EvaluateObjectArgument(Info, Args[0], ThisVal)) 7253 return false; 7254 This = &ThisVal; 7255 Args = Args.slice(1); 7256 } else if (MD && MD->isLambdaStaticInvoker()) { 7257 // Map the static invoker for the lambda back to the call operator. 7258 // Conveniently, we don't have to slice out the 'this' argument (as is 7259 // being done for the non-static case), since a static member function 7260 // doesn't have an implicit argument passed in. 7261 const CXXRecordDecl *ClosureClass = MD->getParent(); 7262 assert( 7263 ClosureClass->captures_begin() == ClosureClass->captures_end() && 7264 "Number of captures must be zero for conversion to function-ptr"); 7265 7266 const CXXMethodDecl *LambdaCallOp = 7267 ClosureClass->getLambdaCallOperator(); 7268 7269 // Set 'FD', the function that will be called below, to the call 7270 // operator. If the closure object represents a generic lambda, find 7271 // the corresponding specialization of the call operator. 7272 7273 if (ClosureClass->isGenericLambda()) { 7274 assert(MD->isFunctionTemplateSpecialization() && 7275 "A generic lambda's static-invoker function must be a " 7276 "template specialization"); 7277 const TemplateArgumentList *TAL = MD->getTemplateSpecializationArgs(); 7278 FunctionTemplateDecl *CallOpTemplate = 7279 LambdaCallOp->getDescribedFunctionTemplate(); 7280 void *InsertPos = nullptr; 7281 FunctionDecl *CorrespondingCallOpSpecialization = 7282 CallOpTemplate->findSpecialization(TAL->asArray(), InsertPos); 7283 assert(CorrespondingCallOpSpecialization && 7284 "We must always have a function call operator specialization " 7285 "that corresponds to our static invoker specialization"); 7286 FD = cast<CXXMethodDecl>(CorrespondingCallOpSpecialization); 7287 } else 7288 FD = LambdaCallOp; 7289 } else if (FD->isReplaceableGlobalAllocationFunction()) { 7290 if (FD->getDeclName().getCXXOverloadedOperator() == OO_New || 7291 FD->getDeclName().getCXXOverloadedOperator() == OO_Array_New) { 7292 LValue Ptr; 7293 if (!HandleOperatorNewCall(Info, E, Ptr)) 7294 return false; 7295 Ptr.moveInto(Result); 7296 return true; 7297 } else { 7298 return HandleOperatorDeleteCall(Info, E); 7299 } 7300 } 7301 } else 7302 return Error(E); 7303 7304 SmallVector<QualType, 4> CovariantAdjustmentPath; 7305 if (This) { 7306 auto *NamedMember = dyn_cast<CXXMethodDecl>(FD); 7307 if (NamedMember && NamedMember->isVirtual() && !HasQualifier) { 7308 // Perform virtual dispatch, if necessary. 7309 FD = HandleVirtualDispatch(Info, E, *This, NamedMember, 7310 CovariantAdjustmentPath); 7311 if (!FD) 7312 return false; 7313 } else { 7314 // Check that the 'this' pointer points to an object of the right type. 7315 // FIXME: If this is an assignment operator call, we may need to change 7316 // the active union member before we check this. 7317 if (!checkNonVirtualMemberCallThisPointer(Info, E, *This, NamedMember)) 7318 return false; 7319 } 7320 } 7321 7322 // Destructor calls are different enough that they have their own codepath. 7323 if (auto *DD = dyn_cast<CXXDestructorDecl>(FD)) { 7324 assert(This && "no 'this' pointer for destructor call"); 7325 return HandleDestruction(Info, E, *This, 7326 Info.Ctx.getRecordType(DD->getParent())); 7327 } 7328 7329 const FunctionDecl *Definition = nullptr; 7330 Stmt *Body = FD->getBody(Definition); 7331 7332 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body) || 7333 !HandleFunctionCall(E->getExprLoc(), Definition, This, Args, Body, Info, 7334 Result, ResultSlot)) 7335 return false; 7336 7337 if (!CovariantAdjustmentPath.empty() && 7338 !HandleCovariantReturnAdjustment(Info, E, Result, 7339 CovariantAdjustmentPath)) 7340 return false; 7341 7342 return true; 7343 } 7344 7345 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) { 7346 return StmtVisitorTy::Visit(E->getInitializer()); 7347 } 7348 bool VisitInitListExpr(const InitListExpr *E) { 7349 if (E->getNumInits() == 0) 7350 return DerivedZeroInitialization(E); 7351 if (E->getNumInits() == 1) 7352 return StmtVisitorTy::Visit(E->getInit(0)); 7353 return Error(E); 7354 } 7355 bool VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) { 7356 return DerivedZeroInitialization(E); 7357 } 7358 bool VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E) { 7359 return DerivedZeroInitialization(E); 7360 } 7361 bool VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E) { 7362 return DerivedZeroInitialization(E); 7363 } 7364 7365 /// A member expression where the object is a prvalue is itself a prvalue. 7366 bool VisitMemberExpr(const MemberExpr *E) { 7367 assert(!Info.Ctx.getLangOpts().CPlusPlus11 && 7368 "missing temporary materialization conversion"); 7369 assert(!E->isArrow() && "missing call to bound member function?"); 7370 7371 APValue Val; 7372 if (!Evaluate(Val, Info, E->getBase())) 7373 return false; 7374 7375 QualType BaseTy = E->getBase()->getType(); 7376 7377 const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl()); 7378 if (!FD) return Error(E); 7379 assert(!FD->getType()->isReferenceType() && "prvalue reference?"); 7380 assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() == 7381 FD->getParent()->getCanonicalDecl() && "record / field mismatch"); 7382 7383 // Note: there is no lvalue base here. But this case should only ever 7384 // happen in C or in C++98, where we cannot be evaluating a constexpr 7385 // constructor, which is the only case the base matters. 7386 CompleteObject Obj(APValue::LValueBase(), &Val, BaseTy); 7387 SubobjectDesignator Designator(BaseTy); 7388 Designator.addDeclUnchecked(FD); 7389 7390 APValue Result; 7391 return extractSubobject(Info, E, Obj, Designator, Result) && 7392 DerivedSuccess(Result, E); 7393 } 7394 7395 bool VisitExtVectorElementExpr(const ExtVectorElementExpr *E) { 7396 APValue Val; 7397 if (!Evaluate(Val, Info, E->getBase())) 7398 return false; 7399 7400 if (Val.isVector()) { 7401 SmallVector<uint32_t, 4> Indices; 7402 E->getEncodedElementAccess(Indices); 7403 if (Indices.size() == 1) { 7404 // Return scalar. 7405 return DerivedSuccess(Val.getVectorElt(Indices[0]), E); 7406 } else { 7407 // Construct new APValue vector. 7408 SmallVector<APValue, 4> Elts; 7409 for (unsigned I = 0; I < Indices.size(); ++I) { 7410 Elts.push_back(Val.getVectorElt(Indices[I])); 7411 } 7412 APValue VecResult(Elts.data(), Indices.size()); 7413 return DerivedSuccess(VecResult, E); 7414 } 7415 } 7416 7417 return false; 7418 } 7419 7420 bool VisitCastExpr(const CastExpr *E) { 7421 switch (E->getCastKind()) { 7422 default: 7423 break; 7424 7425 case CK_AtomicToNonAtomic: { 7426 APValue AtomicVal; 7427 // This does not need to be done in place even for class/array types: 7428 // atomic-to-non-atomic conversion implies copying the object 7429 // representation. 7430 if (!Evaluate(AtomicVal, Info, E->getSubExpr())) 7431 return false; 7432 return DerivedSuccess(AtomicVal, E); 7433 } 7434 7435 case CK_NoOp: 7436 case CK_UserDefinedConversion: 7437 return StmtVisitorTy::Visit(E->getSubExpr()); 7438 7439 case CK_LValueToRValue: { 7440 LValue LVal; 7441 if (!EvaluateLValue(E->getSubExpr(), LVal, Info)) 7442 return false; 7443 APValue RVal; 7444 // Note, we use the subexpression's type in order to retain cv-qualifiers. 7445 if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(), 7446 LVal, RVal)) 7447 return false; 7448 return DerivedSuccess(RVal, E); 7449 } 7450 case CK_LValueToRValueBitCast: { 7451 APValue DestValue, SourceValue; 7452 if (!Evaluate(SourceValue, Info, E->getSubExpr())) 7453 return false; 7454 if (!handleLValueToRValueBitCast(Info, DestValue, SourceValue, E)) 7455 return false; 7456 return DerivedSuccess(DestValue, E); 7457 } 7458 7459 case CK_AddressSpaceConversion: { 7460 APValue Value; 7461 if (!Evaluate(Value, Info, E->getSubExpr())) 7462 return false; 7463 return DerivedSuccess(Value, E); 7464 } 7465 } 7466 7467 return Error(E); 7468 } 7469 7470 bool VisitUnaryPostInc(const UnaryOperator *UO) { 7471 return VisitUnaryPostIncDec(UO); 7472 } 7473 bool VisitUnaryPostDec(const UnaryOperator *UO) { 7474 return VisitUnaryPostIncDec(UO); 7475 } 7476 bool VisitUnaryPostIncDec(const UnaryOperator *UO) { 7477 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure()) 7478 return Error(UO); 7479 7480 LValue LVal; 7481 if (!EvaluateLValue(UO->getSubExpr(), LVal, Info)) 7482 return false; 7483 APValue RVal; 7484 if (!handleIncDec(this->Info, UO, LVal, UO->getSubExpr()->getType(), 7485 UO->isIncrementOp(), &RVal)) 7486 return false; 7487 return DerivedSuccess(RVal, UO); 7488 } 7489 7490 bool VisitStmtExpr(const StmtExpr *E) { 7491 // We will have checked the full-expressions inside the statement expression 7492 // when they were completed, and don't need to check them again now. 7493 if (Info.checkingForUndefinedBehavior()) 7494 return Error(E); 7495 7496 const CompoundStmt *CS = E->getSubStmt(); 7497 if (CS->body_empty()) 7498 return true; 7499 7500 BlockScopeRAII Scope(Info); 7501 for (CompoundStmt::const_body_iterator BI = CS->body_begin(), 7502 BE = CS->body_end(); 7503 /**/; ++BI) { 7504 if (BI + 1 == BE) { 7505 const Expr *FinalExpr = dyn_cast<Expr>(*BI); 7506 if (!FinalExpr) { 7507 Info.FFDiag((*BI)->getBeginLoc(), 7508 diag::note_constexpr_stmt_expr_unsupported); 7509 return false; 7510 } 7511 return this->Visit(FinalExpr) && Scope.destroy(); 7512 } 7513 7514 APValue ReturnValue; 7515 StmtResult Result = { ReturnValue, nullptr }; 7516 EvalStmtResult ESR = EvaluateStmt(Result, Info, *BI); 7517 if (ESR != ESR_Succeeded) { 7518 // FIXME: If the statement-expression terminated due to 'return', 7519 // 'break', or 'continue', it would be nice to propagate that to 7520 // the outer statement evaluation rather than bailing out. 7521 if (ESR != ESR_Failed) 7522 Info.FFDiag((*BI)->getBeginLoc(), 7523 diag::note_constexpr_stmt_expr_unsupported); 7524 return false; 7525 } 7526 } 7527 7528 llvm_unreachable("Return from function from the loop above."); 7529 } 7530 7531 /// Visit a value which is evaluated, but whose value is ignored. 7532 void VisitIgnoredValue(const Expr *E) { 7533 EvaluateIgnoredValue(Info, E); 7534 } 7535 7536 /// Potentially visit a MemberExpr's base expression. 7537 void VisitIgnoredBaseExpression(const Expr *E) { 7538 // While MSVC doesn't evaluate the base expression, it does diagnose the 7539 // presence of side-effecting behavior. 7540 if (Info.getLangOpts().MSVCCompat && !E->HasSideEffects(Info.Ctx)) 7541 return; 7542 VisitIgnoredValue(E); 7543 } 7544 }; 7545 7546 } // namespace 7547 7548 //===----------------------------------------------------------------------===// 7549 // Common base class for lvalue and temporary evaluation. 7550 //===----------------------------------------------------------------------===// 7551 namespace { 7552 template<class Derived> 7553 class LValueExprEvaluatorBase 7554 : public ExprEvaluatorBase<Derived> { 7555 protected: 7556 LValue &Result; 7557 bool InvalidBaseOK; 7558 typedef LValueExprEvaluatorBase LValueExprEvaluatorBaseTy; 7559 typedef ExprEvaluatorBase<Derived> ExprEvaluatorBaseTy; 7560 7561 bool Success(APValue::LValueBase B) { 7562 Result.set(B); 7563 return true; 7564 } 7565 7566 bool evaluatePointer(const Expr *E, LValue &Result) { 7567 return EvaluatePointer(E, Result, this->Info, InvalidBaseOK); 7568 } 7569 7570 public: 7571 LValueExprEvaluatorBase(EvalInfo &Info, LValue &Result, bool InvalidBaseOK) 7572 : ExprEvaluatorBaseTy(Info), Result(Result), 7573 InvalidBaseOK(InvalidBaseOK) {} 7574 7575 bool Success(const APValue &V, const Expr *E) { 7576 Result.setFrom(this->Info.Ctx, V); 7577 return true; 7578 } 7579 7580 bool VisitMemberExpr(const MemberExpr *E) { 7581 // Handle non-static data members. 7582 QualType BaseTy; 7583 bool EvalOK; 7584 if (E->isArrow()) { 7585 EvalOK = evaluatePointer(E->getBase(), Result); 7586 BaseTy = E->getBase()->getType()->castAs<PointerType>()->getPointeeType(); 7587 } else if (E->getBase()->isRValue()) { 7588 assert(E->getBase()->getType()->isRecordType()); 7589 EvalOK = EvaluateTemporary(E->getBase(), Result, this->Info); 7590 BaseTy = E->getBase()->getType(); 7591 } else { 7592 EvalOK = this->Visit(E->getBase()); 7593 BaseTy = E->getBase()->getType(); 7594 } 7595 if (!EvalOK) { 7596 if (!InvalidBaseOK) 7597 return false; 7598 Result.setInvalid(E); 7599 return true; 7600 } 7601 7602 const ValueDecl *MD = E->getMemberDecl(); 7603 if (const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl())) { 7604 assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() == 7605 FD->getParent()->getCanonicalDecl() && "record / field mismatch"); 7606 (void)BaseTy; 7607 if (!HandleLValueMember(this->Info, E, Result, FD)) 7608 return false; 7609 } else if (const IndirectFieldDecl *IFD = dyn_cast<IndirectFieldDecl>(MD)) { 7610 if (!HandleLValueIndirectMember(this->Info, E, Result, IFD)) 7611 return false; 7612 } else 7613 return this->Error(E); 7614 7615 if (MD->getType()->isReferenceType()) { 7616 APValue RefValue; 7617 if (!handleLValueToRValueConversion(this->Info, E, MD->getType(), Result, 7618 RefValue)) 7619 return false; 7620 return Success(RefValue, E); 7621 } 7622 return true; 7623 } 7624 7625 bool VisitBinaryOperator(const BinaryOperator *E) { 7626 switch (E->getOpcode()) { 7627 default: 7628 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 7629 7630 case BO_PtrMemD: 7631 case BO_PtrMemI: 7632 return HandleMemberPointerAccess(this->Info, E, Result); 7633 } 7634 } 7635 7636 bool VisitCastExpr(const CastExpr *E) { 7637 switch (E->getCastKind()) { 7638 default: 7639 return ExprEvaluatorBaseTy::VisitCastExpr(E); 7640 7641 case CK_DerivedToBase: 7642 case CK_UncheckedDerivedToBase: 7643 if (!this->Visit(E->getSubExpr())) 7644 return false; 7645 7646 // Now figure out the necessary offset to add to the base LV to get from 7647 // the derived class to the base class. 7648 return HandleLValueBasePath(this->Info, E, E->getSubExpr()->getType(), 7649 Result); 7650 } 7651 } 7652 }; 7653 } 7654 7655 //===----------------------------------------------------------------------===// 7656 // LValue Evaluation 7657 // 7658 // This is used for evaluating lvalues (in C and C++), xvalues (in C++11), 7659 // function designators (in C), decl references to void objects (in C), and 7660 // temporaries (if building with -Wno-address-of-temporary). 7661 // 7662 // LValue evaluation produces values comprising a base expression of one of the 7663 // following types: 7664 // - Declarations 7665 // * VarDecl 7666 // * FunctionDecl 7667 // - Literals 7668 // * CompoundLiteralExpr in C (and in global scope in C++) 7669 // * StringLiteral 7670 // * PredefinedExpr 7671 // * ObjCStringLiteralExpr 7672 // * ObjCEncodeExpr 7673 // * AddrLabelExpr 7674 // * BlockExpr 7675 // * CallExpr for a MakeStringConstant builtin 7676 // - typeid(T) expressions, as TypeInfoLValues 7677 // - Locals and temporaries 7678 // * MaterializeTemporaryExpr 7679 // * Any Expr, with a CallIndex indicating the function in which the temporary 7680 // was evaluated, for cases where the MaterializeTemporaryExpr is missing 7681 // from the AST (FIXME). 7682 // * A MaterializeTemporaryExpr that has static storage duration, with no 7683 // CallIndex, for a lifetime-extended temporary. 7684 // * The ConstantExpr that is currently being evaluated during evaluation of an 7685 // immediate invocation. 7686 // plus an offset in bytes. 7687 //===----------------------------------------------------------------------===// 7688 namespace { 7689 class LValueExprEvaluator 7690 : public LValueExprEvaluatorBase<LValueExprEvaluator> { 7691 public: 7692 LValueExprEvaluator(EvalInfo &Info, LValue &Result, bool InvalidBaseOK) : 7693 LValueExprEvaluatorBaseTy(Info, Result, InvalidBaseOK) {} 7694 7695 bool VisitVarDecl(const Expr *E, const VarDecl *VD); 7696 bool VisitUnaryPreIncDec(const UnaryOperator *UO); 7697 7698 bool VisitDeclRefExpr(const DeclRefExpr *E); 7699 bool VisitPredefinedExpr(const PredefinedExpr *E) { return Success(E); } 7700 bool VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E); 7701 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E); 7702 bool VisitMemberExpr(const MemberExpr *E); 7703 bool VisitStringLiteral(const StringLiteral *E) { return Success(E); } 7704 bool VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { return Success(E); } 7705 bool VisitCXXTypeidExpr(const CXXTypeidExpr *E); 7706 bool VisitCXXUuidofExpr(const CXXUuidofExpr *E); 7707 bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E); 7708 bool VisitUnaryDeref(const UnaryOperator *E); 7709 bool VisitUnaryReal(const UnaryOperator *E); 7710 bool VisitUnaryImag(const UnaryOperator *E); 7711 bool VisitUnaryPreInc(const UnaryOperator *UO) { 7712 return VisitUnaryPreIncDec(UO); 7713 } 7714 bool VisitUnaryPreDec(const UnaryOperator *UO) { 7715 return VisitUnaryPreIncDec(UO); 7716 } 7717 bool VisitBinAssign(const BinaryOperator *BO); 7718 bool VisitCompoundAssignOperator(const CompoundAssignOperator *CAO); 7719 7720 bool VisitCastExpr(const CastExpr *E) { 7721 switch (E->getCastKind()) { 7722 default: 7723 return LValueExprEvaluatorBaseTy::VisitCastExpr(E); 7724 7725 case CK_LValueBitCast: 7726 this->CCEDiag(E, diag::note_constexpr_invalid_cast) << 2; 7727 if (!Visit(E->getSubExpr())) 7728 return false; 7729 Result.Designator.setInvalid(); 7730 return true; 7731 7732 case CK_BaseToDerived: 7733 if (!Visit(E->getSubExpr())) 7734 return false; 7735 return HandleBaseToDerivedCast(Info, E, Result); 7736 7737 case CK_Dynamic: 7738 if (!Visit(E->getSubExpr())) 7739 return false; 7740 return HandleDynamicCast(Info, cast<ExplicitCastExpr>(E), Result); 7741 } 7742 } 7743 }; 7744 } // end anonymous namespace 7745 7746 /// Evaluate an expression as an lvalue. This can be legitimately called on 7747 /// expressions which are not glvalues, in three cases: 7748 /// * function designators in C, and 7749 /// * "extern void" objects 7750 /// * @selector() expressions in Objective-C 7751 static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info, 7752 bool InvalidBaseOK) { 7753 assert(E->isGLValue() || E->getType()->isFunctionType() || 7754 E->getType()->isVoidType() || isa<ObjCSelectorExpr>(E)); 7755 return LValueExprEvaluator(Info, Result, InvalidBaseOK).Visit(E); 7756 } 7757 7758 bool LValueExprEvaluator::VisitDeclRefExpr(const DeclRefExpr *E) { 7759 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(E->getDecl())) 7760 return Success(FD); 7761 if (const VarDecl *VD = dyn_cast<VarDecl>(E->getDecl())) 7762 return VisitVarDecl(E, VD); 7763 if (const BindingDecl *BD = dyn_cast<BindingDecl>(E->getDecl())) 7764 return Visit(BD->getBinding()); 7765 if (const MSGuidDecl *GD = dyn_cast<MSGuidDecl>(E->getDecl())) 7766 return Success(GD); 7767 return Error(E); 7768 } 7769 7770 7771 bool LValueExprEvaluator::VisitVarDecl(const Expr *E, const VarDecl *VD) { 7772 7773 // If we are within a lambda's call operator, check whether the 'VD' referred 7774 // to within 'E' actually represents a lambda-capture that maps to a 7775 // data-member/field within the closure object, and if so, evaluate to the 7776 // field or what the field refers to. 7777 if (Info.CurrentCall && isLambdaCallOperator(Info.CurrentCall->Callee) && 7778 isa<DeclRefExpr>(E) && 7779 cast<DeclRefExpr>(E)->refersToEnclosingVariableOrCapture()) { 7780 // We don't always have a complete capture-map when checking or inferring if 7781 // the function call operator meets the requirements of a constexpr function 7782 // - but we don't need to evaluate the captures to determine constexprness 7783 // (dcl.constexpr C++17). 7784 if (Info.checkingPotentialConstantExpression()) 7785 return false; 7786 7787 if (auto *FD = Info.CurrentCall->LambdaCaptureFields.lookup(VD)) { 7788 // Start with 'Result' referring to the complete closure object... 7789 Result = *Info.CurrentCall->This; 7790 // ... then update it to refer to the field of the closure object 7791 // that represents the capture. 7792 if (!HandleLValueMember(Info, E, Result, FD)) 7793 return false; 7794 // And if the field is of reference type, update 'Result' to refer to what 7795 // the field refers to. 7796 if (FD->getType()->isReferenceType()) { 7797 APValue RVal; 7798 if (!handleLValueToRValueConversion(Info, E, FD->getType(), Result, 7799 RVal)) 7800 return false; 7801 Result.setFrom(Info.Ctx, RVal); 7802 } 7803 return true; 7804 } 7805 } 7806 CallStackFrame *Frame = nullptr; 7807 if (VD->hasLocalStorage() && Info.CurrentCall->Index > 1) { 7808 // Only if a local variable was declared in the function currently being 7809 // evaluated, do we expect to be able to find its value in the current 7810 // frame. (Otherwise it was likely declared in an enclosing context and 7811 // could either have a valid evaluatable value (for e.g. a constexpr 7812 // variable) or be ill-formed (and trigger an appropriate evaluation 7813 // diagnostic)). 7814 if (Info.CurrentCall->Callee && 7815 Info.CurrentCall->Callee->Equals(VD->getDeclContext())) { 7816 Frame = Info.CurrentCall; 7817 } 7818 } 7819 7820 if (!VD->getType()->isReferenceType()) { 7821 if (Frame) { 7822 Result.set({VD, Frame->Index, 7823 Info.CurrentCall->getCurrentTemporaryVersion(VD)}); 7824 return true; 7825 } 7826 return Success(VD); 7827 } 7828 7829 APValue *V; 7830 if (!evaluateVarDeclInit(Info, E, VD, Frame, V, nullptr)) 7831 return false; 7832 if (!V->hasValue()) { 7833 // FIXME: Is it possible for V to be indeterminate here? If so, we should 7834 // adjust the diagnostic to say that. 7835 if (!Info.checkingPotentialConstantExpression()) 7836 Info.FFDiag(E, diag::note_constexpr_use_uninit_reference); 7837 return false; 7838 } 7839 return Success(*V, E); 7840 } 7841 7842 bool LValueExprEvaluator::VisitMaterializeTemporaryExpr( 7843 const MaterializeTemporaryExpr *E) { 7844 // Walk through the expression to find the materialized temporary itself. 7845 SmallVector<const Expr *, 2> CommaLHSs; 7846 SmallVector<SubobjectAdjustment, 2> Adjustments; 7847 const Expr *Inner = 7848 E->getSubExpr()->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments); 7849 7850 // If we passed any comma operators, evaluate their LHSs. 7851 for (unsigned I = 0, N = CommaLHSs.size(); I != N; ++I) 7852 if (!EvaluateIgnoredValue(Info, CommaLHSs[I])) 7853 return false; 7854 7855 // A materialized temporary with static storage duration can appear within the 7856 // result of a constant expression evaluation, so we need to preserve its 7857 // value for use outside this evaluation. 7858 APValue *Value; 7859 if (E->getStorageDuration() == SD_Static) { 7860 Value = E->getOrCreateValue(true); 7861 *Value = APValue(); 7862 Result.set(E); 7863 } else { 7864 Value = &Info.CurrentCall->createTemporary( 7865 E, E->getType(), E->getStorageDuration() == SD_Automatic, Result); 7866 } 7867 7868 QualType Type = Inner->getType(); 7869 7870 // Materialize the temporary itself. 7871 if (!EvaluateInPlace(*Value, Info, Result, Inner)) { 7872 *Value = APValue(); 7873 return false; 7874 } 7875 7876 // Adjust our lvalue to refer to the desired subobject. 7877 for (unsigned I = Adjustments.size(); I != 0; /**/) { 7878 --I; 7879 switch (Adjustments[I].Kind) { 7880 case SubobjectAdjustment::DerivedToBaseAdjustment: 7881 if (!HandleLValueBasePath(Info, Adjustments[I].DerivedToBase.BasePath, 7882 Type, Result)) 7883 return false; 7884 Type = Adjustments[I].DerivedToBase.BasePath->getType(); 7885 break; 7886 7887 case SubobjectAdjustment::FieldAdjustment: 7888 if (!HandleLValueMember(Info, E, Result, Adjustments[I].Field)) 7889 return false; 7890 Type = Adjustments[I].Field->getType(); 7891 break; 7892 7893 case SubobjectAdjustment::MemberPointerAdjustment: 7894 if (!HandleMemberPointerAccess(this->Info, Type, Result, 7895 Adjustments[I].Ptr.RHS)) 7896 return false; 7897 Type = Adjustments[I].Ptr.MPT->getPointeeType(); 7898 break; 7899 } 7900 } 7901 7902 return true; 7903 } 7904 7905 bool 7906 LValueExprEvaluator::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) { 7907 assert((!Info.getLangOpts().CPlusPlus || E->isFileScope()) && 7908 "lvalue compound literal in c++?"); 7909 // Defer visiting the literal until the lvalue-to-rvalue conversion. We can 7910 // only see this when folding in C, so there's no standard to follow here. 7911 return Success(E); 7912 } 7913 7914 bool LValueExprEvaluator::VisitCXXTypeidExpr(const CXXTypeidExpr *E) { 7915 TypeInfoLValue TypeInfo; 7916 7917 if (!E->isPotentiallyEvaluated()) { 7918 if (E->isTypeOperand()) 7919 TypeInfo = TypeInfoLValue(E->getTypeOperand(Info.Ctx).getTypePtr()); 7920 else 7921 TypeInfo = TypeInfoLValue(E->getExprOperand()->getType().getTypePtr()); 7922 } else { 7923 if (!Info.Ctx.getLangOpts().CPlusPlus20) { 7924 Info.CCEDiag(E, diag::note_constexpr_typeid_polymorphic) 7925 << E->getExprOperand()->getType() 7926 << E->getExprOperand()->getSourceRange(); 7927 } 7928 7929 if (!Visit(E->getExprOperand())) 7930 return false; 7931 7932 Optional<DynamicType> DynType = 7933 ComputeDynamicType(Info, E, Result, AK_TypeId); 7934 if (!DynType) 7935 return false; 7936 7937 TypeInfo = 7938 TypeInfoLValue(Info.Ctx.getRecordType(DynType->Type).getTypePtr()); 7939 } 7940 7941 return Success(APValue::LValueBase::getTypeInfo(TypeInfo, E->getType())); 7942 } 7943 7944 bool LValueExprEvaluator::VisitCXXUuidofExpr(const CXXUuidofExpr *E) { 7945 return Success(E->getGuidDecl()); 7946 } 7947 7948 bool LValueExprEvaluator::VisitMemberExpr(const MemberExpr *E) { 7949 // Handle static data members. 7950 if (const VarDecl *VD = dyn_cast<VarDecl>(E->getMemberDecl())) { 7951 VisitIgnoredBaseExpression(E->getBase()); 7952 return VisitVarDecl(E, VD); 7953 } 7954 7955 // Handle static member functions. 7956 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(E->getMemberDecl())) { 7957 if (MD->isStatic()) { 7958 VisitIgnoredBaseExpression(E->getBase()); 7959 return Success(MD); 7960 } 7961 } 7962 7963 // Handle non-static data members. 7964 return LValueExprEvaluatorBaseTy::VisitMemberExpr(E); 7965 } 7966 7967 bool LValueExprEvaluator::VisitArraySubscriptExpr(const ArraySubscriptExpr *E) { 7968 // FIXME: Deal with vectors as array subscript bases. 7969 if (E->getBase()->getType()->isVectorType()) 7970 return Error(E); 7971 7972 bool Success = true; 7973 if (!evaluatePointer(E->getBase(), Result)) { 7974 if (!Info.noteFailure()) 7975 return false; 7976 Success = false; 7977 } 7978 7979 APSInt Index; 7980 if (!EvaluateInteger(E->getIdx(), Index, Info)) 7981 return false; 7982 7983 return Success && 7984 HandleLValueArrayAdjustment(Info, E, Result, E->getType(), Index); 7985 } 7986 7987 bool LValueExprEvaluator::VisitUnaryDeref(const UnaryOperator *E) { 7988 return evaluatePointer(E->getSubExpr(), Result); 7989 } 7990 7991 bool LValueExprEvaluator::VisitUnaryReal(const UnaryOperator *E) { 7992 if (!Visit(E->getSubExpr())) 7993 return false; 7994 // __real is a no-op on scalar lvalues. 7995 if (E->getSubExpr()->getType()->isAnyComplexType()) 7996 HandleLValueComplexElement(Info, E, Result, E->getType(), false); 7997 return true; 7998 } 7999 8000 bool LValueExprEvaluator::VisitUnaryImag(const UnaryOperator *E) { 8001 assert(E->getSubExpr()->getType()->isAnyComplexType() && 8002 "lvalue __imag__ on scalar?"); 8003 if (!Visit(E->getSubExpr())) 8004 return false; 8005 HandleLValueComplexElement(Info, E, Result, E->getType(), true); 8006 return true; 8007 } 8008 8009 bool LValueExprEvaluator::VisitUnaryPreIncDec(const UnaryOperator *UO) { 8010 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure()) 8011 return Error(UO); 8012 8013 if (!this->Visit(UO->getSubExpr())) 8014 return false; 8015 8016 return handleIncDec( 8017 this->Info, UO, Result, UO->getSubExpr()->getType(), 8018 UO->isIncrementOp(), nullptr); 8019 } 8020 8021 bool LValueExprEvaluator::VisitCompoundAssignOperator( 8022 const CompoundAssignOperator *CAO) { 8023 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure()) 8024 return Error(CAO); 8025 8026 APValue RHS; 8027 8028 // The overall lvalue result is the result of evaluating the LHS. 8029 if (!this->Visit(CAO->getLHS())) { 8030 if (Info.noteFailure()) 8031 Evaluate(RHS, this->Info, CAO->getRHS()); 8032 return false; 8033 } 8034 8035 if (!Evaluate(RHS, this->Info, CAO->getRHS())) 8036 return false; 8037 8038 return handleCompoundAssignment( 8039 this->Info, CAO, 8040 Result, CAO->getLHS()->getType(), CAO->getComputationLHSType(), 8041 CAO->getOpForCompoundAssignment(CAO->getOpcode()), RHS); 8042 } 8043 8044 bool LValueExprEvaluator::VisitBinAssign(const BinaryOperator *E) { 8045 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure()) 8046 return Error(E); 8047 8048 APValue NewVal; 8049 8050 if (!this->Visit(E->getLHS())) { 8051 if (Info.noteFailure()) 8052 Evaluate(NewVal, this->Info, E->getRHS()); 8053 return false; 8054 } 8055 8056 if (!Evaluate(NewVal, this->Info, E->getRHS())) 8057 return false; 8058 8059 if (Info.getLangOpts().CPlusPlus20 && 8060 !HandleUnionActiveMemberChange(Info, E->getLHS(), Result)) 8061 return false; 8062 8063 return handleAssignment(this->Info, E, Result, E->getLHS()->getType(), 8064 NewVal); 8065 } 8066 8067 //===----------------------------------------------------------------------===// 8068 // Pointer Evaluation 8069 //===----------------------------------------------------------------------===// 8070 8071 /// Attempts to compute the number of bytes available at the pointer 8072 /// returned by a function with the alloc_size attribute. Returns true if we 8073 /// were successful. Places an unsigned number into `Result`. 8074 /// 8075 /// This expects the given CallExpr to be a call to a function with an 8076 /// alloc_size attribute. 8077 static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx, 8078 const CallExpr *Call, 8079 llvm::APInt &Result) { 8080 const AllocSizeAttr *AllocSize = getAllocSizeAttr(Call); 8081 8082 assert(AllocSize && AllocSize->getElemSizeParam().isValid()); 8083 unsigned SizeArgNo = AllocSize->getElemSizeParam().getASTIndex(); 8084 unsigned BitsInSizeT = Ctx.getTypeSize(Ctx.getSizeType()); 8085 if (Call->getNumArgs() <= SizeArgNo) 8086 return false; 8087 8088 auto EvaluateAsSizeT = [&](const Expr *E, APSInt &Into) { 8089 Expr::EvalResult ExprResult; 8090 if (!E->EvaluateAsInt(ExprResult, Ctx, Expr::SE_AllowSideEffects)) 8091 return false; 8092 Into = ExprResult.Val.getInt(); 8093 if (Into.isNegative() || !Into.isIntN(BitsInSizeT)) 8094 return false; 8095 Into = Into.zextOrSelf(BitsInSizeT); 8096 return true; 8097 }; 8098 8099 APSInt SizeOfElem; 8100 if (!EvaluateAsSizeT(Call->getArg(SizeArgNo), SizeOfElem)) 8101 return false; 8102 8103 if (!AllocSize->getNumElemsParam().isValid()) { 8104 Result = std::move(SizeOfElem); 8105 return true; 8106 } 8107 8108 APSInt NumberOfElems; 8109 unsigned NumArgNo = AllocSize->getNumElemsParam().getASTIndex(); 8110 if (!EvaluateAsSizeT(Call->getArg(NumArgNo), NumberOfElems)) 8111 return false; 8112 8113 bool Overflow; 8114 llvm::APInt BytesAvailable = SizeOfElem.umul_ov(NumberOfElems, Overflow); 8115 if (Overflow) 8116 return false; 8117 8118 Result = std::move(BytesAvailable); 8119 return true; 8120 } 8121 8122 /// Convenience function. LVal's base must be a call to an alloc_size 8123 /// function. 8124 static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx, 8125 const LValue &LVal, 8126 llvm::APInt &Result) { 8127 assert(isBaseAnAllocSizeCall(LVal.getLValueBase()) && 8128 "Can't get the size of a non alloc_size function"); 8129 const auto *Base = LVal.getLValueBase().get<const Expr *>(); 8130 const CallExpr *CE = tryUnwrapAllocSizeCall(Base); 8131 return getBytesReturnedByAllocSizeCall(Ctx, CE, Result); 8132 } 8133 8134 /// Attempts to evaluate the given LValueBase as the result of a call to 8135 /// a function with the alloc_size attribute. If it was possible to do so, this 8136 /// function will return true, make Result's Base point to said function call, 8137 /// and mark Result's Base as invalid. 8138 static bool evaluateLValueAsAllocSize(EvalInfo &Info, APValue::LValueBase Base, 8139 LValue &Result) { 8140 if (Base.isNull()) 8141 return false; 8142 8143 // Because we do no form of static analysis, we only support const variables. 8144 // 8145 // Additionally, we can't support parameters, nor can we support static 8146 // variables (in the latter case, use-before-assign isn't UB; in the former, 8147 // we have no clue what they'll be assigned to). 8148 const auto *VD = 8149 dyn_cast_or_null<VarDecl>(Base.dyn_cast<const ValueDecl *>()); 8150 if (!VD || !VD->isLocalVarDecl() || !VD->getType().isConstQualified()) 8151 return false; 8152 8153 const Expr *Init = VD->getAnyInitializer(); 8154 if (!Init) 8155 return false; 8156 8157 const Expr *E = Init->IgnoreParens(); 8158 if (!tryUnwrapAllocSizeCall(E)) 8159 return false; 8160 8161 // Store E instead of E unwrapped so that the type of the LValue's base is 8162 // what the user wanted. 8163 Result.setInvalid(E); 8164 8165 QualType Pointee = E->getType()->castAs<PointerType>()->getPointeeType(); 8166 Result.addUnsizedArray(Info, E, Pointee); 8167 return true; 8168 } 8169 8170 namespace { 8171 class PointerExprEvaluator 8172 : public ExprEvaluatorBase<PointerExprEvaluator> { 8173 LValue &Result; 8174 bool InvalidBaseOK; 8175 8176 bool Success(const Expr *E) { 8177 Result.set(E); 8178 return true; 8179 } 8180 8181 bool evaluateLValue(const Expr *E, LValue &Result) { 8182 return EvaluateLValue(E, Result, Info, InvalidBaseOK); 8183 } 8184 8185 bool evaluatePointer(const Expr *E, LValue &Result) { 8186 return EvaluatePointer(E, Result, Info, InvalidBaseOK); 8187 } 8188 8189 bool visitNonBuiltinCallExpr(const CallExpr *E); 8190 public: 8191 8192 PointerExprEvaluator(EvalInfo &info, LValue &Result, bool InvalidBaseOK) 8193 : ExprEvaluatorBaseTy(info), Result(Result), 8194 InvalidBaseOK(InvalidBaseOK) {} 8195 8196 bool Success(const APValue &V, const Expr *E) { 8197 Result.setFrom(Info.Ctx, V); 8198 return true; 8199 } 8200 bool ZeroInitialization(const Expr *E) { 8201 Result.setNull(Info.Ctx, E->getType()); 8202 return true; 8203 } 8204 8205 bool VisitBinaryOperator(const BinaryOperator *E); 8206 bool VisitCastExpr(const CastExpr* E); 8207 bool VisitUnaryAddrOf(const UnaryOperator *E); 8208 bool VisitObjCStringLiteral(const ObjCStringLiteral *E) 8209 { return Success(E); } 8210 bool VisitObjCBoxedExpr(const ObjCBoxedExpr *E) { 8211 if (E->isExpressibleAsConstantInitializer()) 8212 return Success(E); 8213 if (Info.noteFailure()) 8214 EvaluateIgnoredValue(Info, E->getSubExpr()); 8215 return Error(E); 8216 } 8217 bool VisitAddrLabelExpr(const AddrLabelExpr *E) 8218 { return Success(E); } 8219 bool VisitCallExpr(const CallExpr *E); 8220 bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp); 8221 bool VisitBlockExpr(const BlockExpr *E) { 8222 if (!E->getBlockDecl()->hasCaptures()) 8223 return Success(E); 8224 return Error(E); 8225 } 8226 bool VisitCXXThisExpr(const CXXThisExpr *E) { 8227 // Can't look at 'this' when checking a potential constant expression. 8228 if (Info.checkingPotentialConstantExpression()) 8229 return false; 8230 if (!Info.CurrentCall->This) { 8231 if (Info.getLangOpts().CPlusPlus11) 8232 Info.FFDiag(E, diag::note_constexpr_this) << E->isImplicit(); 8233 else 8234 Info.FFDiag(E); 8235 return false; 8236 } 8237 Result = *Info.CurrentCall->This; 8238 // If we are inside a lambda's call operator, the 'this' expression refers 8239 // to the enclosing '*this' object (either by value or reference) which is 8240 // either copied into the closure object's field that represents the '*this' 8241 // or refers to '*this'. 8242 if (isLambdaCallOperator(Info.CurrentCall->Callee)) { 8243 // Ensure we actually have captured 'this'. (an error will have 8244 // been previously reported if not). 8245 if (!Info.CurrentCall->LambdaThisCaptureField) 8246 return false; 8247 8248 // Update 'Result' to refer to the data member/field of the closure object 8249 // that represents the '*this' capture. 8250 if (!HandleLValueMember(Info, E, Result, 8251 Info.CurrentCall->LambdaThisCaptureField)) 8252 return false; 8253 // If we captured '*this' by reference, replace the field with its referent. 8254 if (Info.CurrentCall->LambdaThisCaptureField->getType() 8255 ->isPointerType()) { 8256 APValue RVal; 8257 if (!handleLValueToRValueConversion(Info, E, E->getType(), Result, 8258 RVal)) 8259 return false; 8260 8261 Result.setFrom(Info.Ctx, RVal); 8262 } 8263 } 8264 return true; 8265 } 8266 8267 bool VisitCXXNewExpr(const CXXNewExpr *E); 8268 8269 bool VisitSourceLocExpr(const SourceLocExpr *E) { 8270 assert(E->isStringType() && "SourceLocExpr isn't a pointer type?"); 8271 APValue LValResult = E->EvaluateInContext( 8272 Info.Ctx, Info.CurrentCall->CurSourceLocExprScope.getDefaultExpr()); 8273 Result.setFrom(Info.Ctx, LValResult); 8274 return true; 8275 } 8276 8277 // FIXME: Missing: @protocol, @selector 8278 }; 8279 } // end anonymous namespace 8280 8281 static bool EvaluatePointer(const Expr* E, LValue& Result, EvalInfo &Info, 8282 bool InvalidBaseOK) { 8283 assert(E->isRValue() && E->getType()->hasPointerRepresentation()); 8284 return PointerExprEvaluator(Info, Result, InvalidBaseOK).Visit(E); 8285 } 8286 8287 bool PointerExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { 8288 if (E->getOpcode() != BO_Add && 8289 E->getOpcode() != BO_Sub) 8290 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 8291 8292 const Expr *PExp = E->getLHS(); 8293 const Expr *IExp = E->getRHS(); 8294 if (IExp->getType()->isPointerType()) 8295 std::swap(PExp, IExp); 8296 8297 bool EvalPtrOK = evaluatePointer(PExp, Result); 8298 if (!EvalPtrOK && !Info.noteFailure()) 8299 return false; 8300 8301 llvm::APSInt Offset; 8302 if (!EvaluateInteger(IExp, Offset, Info) || !EvalPtrOK) 8303 return false; 8304 8305 if (E->getOpcode() == BO_Sub) 8306 negateAsSigned(Offset); 8307 8308 QualType Pointee = PExp->getType()->castAs<PointerType>()->getPointeeType(); 8309 return HandleLValueArrayAdjustment(Info, E, Result, Pointee, Offset); 8310 } 8311 8312 bool PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) { 8313 return evaluateLValue(E->getSubExpr(), Result); 8314 } 8315 8316 bool PointerExprEvaluator::VisitCastExpr(const CastExpr *E) { 8317 const Expr *SubExpr = E->getSubExpr(); 8318 8319 switch (E->getCastKind()) { 8320 default: 8321 break; 8322 case CK_BitCast: 8323 case CK_CPointerToObjCPointerCast: 8324 case CK_BlockPointerToObjCPointerCast: 8325 case CK_AnyPointerToBlockPointerCast: 8326 case CK_AddressSpaceConversion: 8327 if (!Visit(SubExpr)) 8328 return false; 8329 // Bitcasts to cv void* are static_casts, not reinterpret_casts, so are 8330 // permitted in constant expressions in C++11. Bitcasts from cv void* are 8331 // also static_casts, but we disallow them as a resolution to DR1312. 8332 if (!E->getType()->isVoidPointerType()) { 8333 if (!Result.InvalidBase && !Result.Designator.Invalid && 8334 !Result.IsNullPtr && 8335 Info.Ctx.hasSameUnqualifiedType(Result.Designator.getType(Info.Ctx), 8336 E->getType()->getPointeeType()) && 8337 Info.getStdAllocatorCaller("allocate")) { 8338 // Inside a call to std::allocator::allocate and friends, we permit 8339 // casting from void* back to cv1 T* for a pointer that points to a 8340 // cv2 T. 8341 } else { 8342 Result.Designator.setInvalid(); 8343 if (SubExpr->getType()->isVoidPointerType()) 8344 CCEDiag(E, diag::note_constexpr_invalid_cast) 8345 << 3 << SubExpr->getType(); 8346 else 8347 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2; 8348 } 8349 } 8350 if (E->getCastKind() == CK_AddressSpaceConversion && Result.IsNullPtr) 8351 ZeroInitialization(E); 8352 return true; 8353 8354 case CK_DerivedToBase: 8355 case CK_UncheckedDerivedToBase: 8356 if (!evaluatePointer(E->getSubExpr(), Result)) 8357 return false; 8358 if (!Result.Base && Result.Offset.isZero()) 8359 return true; 8360 8361 // Now figure out the necessary offset to add to the base LV to get from 8362 // the derived class to the base class. 8363 return HandleLValueBasePath(Info, E, E->getSubExpr()->getType()-> 8364 castAs<PointerType>()->getPointeeType(), 8365 Result); 8366 8367 case CK_BaseToDerived: 8368 if (!Visit(E->getSubExpr())) 8369 return false; 8370 if (!Result.Base && Result.Offset.isZero()) 8371 return true; 8372 return HandleBaseToDerivedCast(Info, E, Result); 8373 8374 case CK_Dynamic: 8375 if (!Visit(E->getSubExpr())) 8376 return false; 8377 return HandleDynamicCast(Info, cast<ExplicitCastExpr>(E), Result); 8378 8379 case CK_NullToPointer: 8380 VisitIgnoredValue(E->getSubExpr()); 8381 return ZeroInitialization(E); 8382 8383 case CK_IntegralToPointer: { 8384 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2; 8385 8386 APValue Value; 8387 if (!EvaluateIntegerOrLValue(SubExpr, Value, Info)) 8388 break; 8389 8390 if (Value.isInt()) { 8391 unsigned Size = Info.Ctx.getTypeSize(E->getType()); 8392 uint64_t N = Value.getInt().extOrTrunc(Size).getZExtValue(); 8393 Result.Base = (Expr*)nullptr; 8394 Result.InvalidBase = false; 8395 Result.Offset = CharUnits::fromQuantity(N); 8396 Result.Designator.setInvalid(); 8397 Result.IsNullPtr = false; 8398 return true; 8399 } else { 8400 // Cast is of an lvalue, no need to change value. 8401 Result.setFrom(Info.Ctx, Value); 8402 return true; 8403 } 8404 } 8405 8406 case CK_ArrayToPointerDecay: { 8407 if (SubExpr->isGLValue()) { 8408 if (!evaluateLValue(SubExpr, Result)) 8409 return false; 8410 } else { 8411 APValue &Value = Info.CurrentCall->createTemporary( 8412 SubExpr, SubExpr->getType(), false, Result); 8413 if (!EvaluateInPlace(Value, Info, Result, SubExpr)) 8414 return false; 8415 } 8416 // The result is a pointer to the first element of the array. 8417 auto *AT = Info.Ctx.getAsArrayType(SubExpr->getType()); 8418 if (auto *CAT = dyn_cast<ConstantArrayType>(AT)) 8419 Result.addArray(Info, E, CAT); 8420 else 8421 Result.addUnsizedArray(Info, E, AT->getElementType()); 8422 return true; 8423 } 8424 8425 case CK_FunctionToPointerDecay: 8426 return evaluateLValue(SubExpr, Result); 8427 8428 case CK_LValueToRValue: { 8429 LValue LVal; 8430 if (!evaluateLValue(E->getSubExpr(), LVal)) 8431 return false; 8432 8433 APValue RVal; 8434 // Note, we use the subexpression's type in order to retain cv-qualifiers. 8435 if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(), 8436 LVal, RVal)) 8437 return InvalidBaseOK && 8438 evaluateLValueAsAllocSize(Info, LVal.Base, Result); 8439 return Success(RVal, E); 8440 } 8441 } 8442 8443 return ExprEvaluatorBaseTy::VisitCastExpr(E); 8444 } 8445 8446 static CharUnits GetAlignOfType(EvalInfo &Info, QualType T, 8447 UnaryExprOrTypeTrait ExprKind) { 8448 // C++ [expr.alignof]p3: 8449 // When alignof is applied to a reference type, the result is the 8450 // alignment of the referenced type. 8451 if (const ReferenceType *Ref = T->getAs<ReferenceType>()) 8452 T = Ref->getPointeeType(); 8453 8454 if (T.getQualifiers().hasUnaligned()) 8455 return CharUnits::One(); 8456 8457 const bool AlignOfReturnsPreferred = 8458 Info.Ctx.getLangOpts().getClangABICompat() <= LangOptions::ClangABI::Ver7; 8459 8460 // __alignof is defined to return the preferred alignment. 8461 // Before 8, clang returned the preferred alignment for alignof and _Alignof 8462 // as well. 8463 if (ExprKind == UETT_PreferredAlignOf || AlignOfReturnsPreferred) 8464 return Info.Ctx.toCharUnitsFromBits( 8465 Info.Ctx.getPreferredTypeAlign(T.getTypePtr())); 8466 // alignof and _Alignof are defined to return the ABI alignment. 8467 else if (ExprKind == UETT_AlignOf) 8468 return Info.Ctx.getTypeAlignInChars(T.getTypePtr()); 8469 else 8470 llvm_unreachable("GetAlignOfType on a non-alignment ExprKind"); 8471 } 8472 8473 static CharUnits GetAlignOfExpr(EvalInfo &Info, const Expr *E, 8474 UnaryExprOrTypeTrait ExprKind) { 8475 E = E->IgnoreParens(); 8476 8477 // The kinds of expressions that we have special-case logic here for 8478 // should be kept up to date with the special checks for those 8479 // expressions in Sema. 8480 8481 // alignof decl is always accepted, even if it doesn't make sense: we default 8482 // to 1 in those cases. 8483 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 8484 return Info.Ctx.getDeclAlign(DRE->getDecl(), 8485 /*RefAsPointee*/true); 8486 8487 if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) 8488 return Info.Ctx.getDeclAlign(ME->getMemberDecl(), 8489 /*RefAsPointee*/true); 8490 8491 return GetAlignOfType(Info, E->getType(), ExprKind); 8492 } 8493 8494 static CharUnits getBaseAlignment(EvalInfo &Info, const LValue &Value) { 8495 if (const auto *VD = Value.Base.dyn_cast<const ValueDecl *>()) 8496 return Info.Ctx.getDeclAlign(VD); 8497 if (const auto *E = Value.Base.dyn_cast<const Expr *>()) 8498 return GetAlignOfExpr(Info, E, UETT_AlignOf); 8499 return GetAlignOfType(Info, Value.Base.getTypeInfoType(), UETT_AlignOf); 8500 } 8501 8502 /// Evaluate the value of the alignment argument to __builtin_align_{up,down}, 8503 /// __builtin_is_aligned and __builtin_assume_aligned. 8504 static bool getAlignmentArgument(const Expr *E, QualType ForType, 8505 EvalInfo &Info, APSInt &Alignment) { 8506 if (!EvaluateInteger(E, Alignment, Info)) 8507 return false; 8508 if (Alignment < 0 || !Alignment.isPowerOf2()) { 8509 Info.FFDiag(E, diag::note_constexpr_invalid_alignment) << Alignment; 8510 return false; 8511 } 8512 unsigned SrcWidth = Info.Ctx.getIntWidth(ForType); 8513 APSInt MaxValue(APInt::getOneBitSet(SrcWidth, SrcWidth - 1)); 8514 if (APSInt::compareValues(Alignment, MaxValue) > 0) { 8515 Info.FFDiag(E, diag::note_constexpr_alignment_too_big) 8516 << MaxValue << ForType << Alignment; 8517 return false; 8518 } 8519 // Ensure both alignment and source value have the same bit width so that we 8520 // don't assert when computing the resulting value. 8521 APSInt ExtAlignment = 8522 APSInt(Alignment.zextOrTrunc(SrcWidth), /*isUnsigned=*/true); 8523 assert(APSInt::compareValues(Alignment, ExtAlignment) == 0 && 8524 "Alignment should not be changed by ext/trunc"); 8525 Alignment = ExtAlignment; 8526 assert(Alignment.getBitWidth() == SrcWidth); 8527 return true; 8528 } 8529 8530 // To be clear: this happily visits unsupported builtins. Better name welcomed. 8531 bool PointerExprEvaluator::visitNonBuiltinCallExpr(const CallExpr *E) { 8532 if (ExprEvaluatorBaseTy::VisitCallExpr(E)) 8533 return true; 8534 8535 if (!(InvalidBaseOK && getAllocSizeAttr(E))) 8536 return false; 8537 8538 Result.setInvalid(E); 8539 QualType PointeeTy = E->getType()->castAs<PointerType>()->getPointeeType(); 8540 Result.addUnsizedArray(Info, E, PointeeTy); 8541 return true; 8542 } 8543 8544 bool PointerExprEvaluator::VisitCallExpr(const CallExpr *E) { 8545 if (IsStringLiteralCall(E)) 8546 return Success(E); 8547 8548 if (unsigned BuiltinOp = E->getBuiltinCallee()) 8549 return VisitBuiltinCallExpr(E, BuiltinOp); 8550 8551 return visitNonBuiltinCallExpr(E); 8552 } 8553 8554 // Determine if T is a character type for which we guarantee that 8555 // sizeof(T) == 1. 8556 static bool isOneByteCharacterType(QualType T) { 8557 return T->isCharType() || T->isChar8Type(); 8558 } 8559 8560 bool PointerExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E, 8561 unsigned BuiltinOp) { 8562 switch (BuiltinOp) { 8563 case Builtin::BI__builtin_addressof: 8564 return evaluateLValue(E->getArg(0), Result); 8565 case Builtin::BI__builtin_assume_aligned: { 8566 // We need to be very careful here because: if the pointer does not have the 8567 // asserted alignment, then the behavior is undefined, and undefined 8568 // behavior is non-constant. 8569 if (!evaluatePointer(E->getArg(0), Result)) 8570 return false; 8571 8572 LValue OffsetResult(Result); 8573 APSInt Alignment; 8574 if (!getAlignmentArgument(E->getArg(1), E->getArg(0)->getType(), Info, 8575 Alignment)) 8576 return false; 8577 CharUnits Align = CharUnits::fromQuantity(Alignment.getZExtValue()); 8578 8579 if (E->getNumArgs() > 2) { 8580 APSInt Offset; 8581 if (!EvaluateInteger(E->getArg(2), Offset, Info)) 8582 return false; 8583 8584 int64_t AdditionalOffset = -Offset.getZExtValue(); 8585 OffsetResult.Offset += CharUnits::fromQuantity(AdditionalOffset); 8586 } 8587 8588 // If there is a base object, then it must have the correct alignment. 8589 if (OffsetResult.Base) { 8590 CharUnits BaseAlignment = getBaseAlignment(Info, OffsetResult); 8591 8592 if (BaseAlignment < Align) { 8593 Result.Designator.setInvalid(); 8594 // FIXME: Add support to Diagnostic for long / long long. 8595 CCEDiag(E->getArg(0), 8596 diag::note_constexpr_baa_insufficient_alignment) << 0 8597 << (unsigned)BaseAlignment.getQuantity() 8598 << (unsigned)Align.getQuantity(); 8599 return false; 8600 } 8601 } 8602 8603 // The offset must also have the correct alignment. 8604 if (OffsetResult.Offset.alignTo(Align) != OffsetResult.Offset) { 8605 Result.Designator.setInvalid(); 8606 8607 (OffsetResult.Base 8608 ? CCEDiag(E->getArg(0), 8609 diag::note_constexpr_baa_insufficient_alignment) << 1 8610 : CCEDiag(E->getArg(0), 8611 diag::note_constexpr_baa_value_insufficient_alignment)) 8612 << (int)OffsetResult.Offset.getQuantity() 8613 << (unsigned)Align.getQuantity(); 8614 return false; 8615 } 8616 8617 return true; 8618 } 8619 case Builtin::BI__builtin_align_up: 8620 case Builtin::BI__builtin_align_down: { 8621 if (!evaluatePointer(E->getArg(0), Result)) 8622 return false; 8623 APSInt Alignment; 8624 if (!getAlignmentArgument(E->getArg(1), E->getArg(0)->getType(), Info, 8625 Alignment)) 8626 return false; 8627 CharUnits BaseAlignment = getBaseAlignment(Info, Result); 8628 CharUnits PtrAlign = BaseAlignment.alignmentAtOffset(Result.Offset); 8629 // For align_up/align_down, we can return the same value if the alignment 8630 // is known to be greater or equal to the requested value. 8631 if (PtrAlign.getQuantity() >= Alignment) 8632 return true; 8633 8634 // The alignment could be greater than the minimum at run-time, so we cannot 8635 // infer much about the resulting pointer value. One case is possible: 8636 // For `_Alignas(32) char buf[N]; __builtin_align_down(&buf[idx], 32)` we 8637 // can infer the correct index if the requested alignment is smaller than 8638 // the base alignment so we can perform the computation on the offset. 8639 if (BaseAlignment.getQuantity() >= Alignment) { 8640 assert(Alignment.getBitWidth() <= 64 && 8641 "Cannot handle > 64-bit address-space"); 8642 uint64_t Alignment64 = Alignment.getZExtValue(); 8643 CharUnits NewOffset = CharUnits::fromQuantity( 8644 BuiltinOp == Builtin::BI__builtin_align_down 8645 ? llvm::alignDown(Result.Offset.getQuantity(), Alignment64) 8646 : llvm::alignTo(Result.Offset.getQuantity(), Alignment64)); 8647 Result.adjustOffset(NewOffset - Result.Offset); 8648 // TODO: diagnose out-of-bounds values/only allow for arrays? 8649 return true; 8650 } 8651 // Otherwise, we cannot constant-evaluate the result. 8652 Info.FFDiag(E->getArg(0), diag::note_constexpr_alignment_adjust) 8653 << Alignment; 8654 return false; 8655 } 8656 case Builtin::BI__builtin_operator_new: 8657 return HandleOperatorNewCall(Info, E, Result); 8658 case Builtin::BI__builtin_launder: 8659 return evaluatePointer(E->getArg(0), Result); 8660 case Builtin::BIstrchr: 8661 case Builtin::BIwcschr: 8662 case Builtin::BImemchr: 8663 case Builtin::BIwmemchr: 8664 if (Info.getLangOpts().CPlusPlus11) 8665 Info.CCEDiag(E, diag::note_constexpr_invalid_function) 8666 << /*isConstexpr*/0 << /*isConstructor*/0 8667 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'"); 8668 else 8669 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr); 8670 LLVM_FALLTHROUGH; 8671 case Builtin::BI__builtin_strchr: 8672 case Builtin::BI__builtin_wcschr: 8673 case Builtin::BI__builtin_memchr: 8674 case Builtin::BI__builtin_char_memchr: 8675 case Builtin::BI__builtin_wmemchr: { 8676 if (!Visit(E->getArg(0))) 8677 return false; 8678 APSInt Desired; 8679 if (!EvaluateInteger(E->getArg(1), Desired, Info)) 8680 return false; 8681 uint64_t MaxLength = uint64_t(-1); 8682 if (BuiltinOp != Builtin::BIstrchr && 8683 BuiltinOp != Builtin::BIwcschr && 8684 BuiltinOp != Builtin::BI__builtin_strchr && 8685 BuiltinOp != Builtin::BI__builtin_wcschr) { 8686 APSInt N; 8687 if (!EvaluateInteger(E->getArg(2), N, Info)) 8688 return false; 8689 MaxLength = N.getExtValue(); 8690 } 8691 // We cannot find the value if there are no candidates to match against. 8692 if (MaxLength == 0u) 8693 return ZeroInitialization(E); 8694 if (!Result.checkNullPointerForFoldAccess(Info, E, AK_Read) || 8695 Result.Designator.Invalid) 8696 return false; 8697 QualType CharTy = Result.Designator.getType(Info.Ctx); 8698 bool IsRawByte = BuiltinOp == Builtin::BImemchr || 8699 BuiltinOp == Builtin::BI__builtin_memchr; 8700 assert(IsRawByte || 8701 Info.Ctx.hasSameUnqualifiedType( 8702 CharTy, E->getArg(0)->getType()->getPointeeType())); 8703 // Pointers to const void may point to objects of incomplete type. 8704 if (IsRawByte && CharTy->isIncompleteType()) { 8705 Info.FFDiag(E, diag::note_constexpr_ltor_incomplete_type) << CharTy; 8706 return false; 8707 } 8708 // Give up on byte-oriented matching against multibyte elements. 8709 // FIXME: We can compare the bytes in the correct order. 8710 if (IsRawByte && !isOneByteCharacterType(CharTy)) { 8711 Info.FFDiag(E, diag::note_constexpr_memchr_unsupported) 8712 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'") 8713 << CharTy; 8714 return false; 8715 } 8716 // Figure out what value we're actually looking for (after converting to 8717 // the corresponding unsigned type if necessary). 8718 uint64_t DesiredVal; 8719 bool StopAtNull = false; 8720 switch (BuiltinOp) { 8721 case Builtin::BIstrchr: 8722 case Builtin::BI__builtin_strchr: 8723 // strchr compares directly to the passed integer, and therefore 8724 // always fails if given an int that is not a char. 8725 if (!APSInt::isSameValue(HandleIntToIntCast(Info, E, CharTy, 8726 E->getArg(1)->getType(), 8727 Desired), 8728 Desired)) 8729 return ZeroInitialization(E); 8730 StopAtNull = true; 8731 LLVM_FALLTHROUGH; 8732 case Builtin::BImemchr: 8733 case Builtin::BI__builtin_memchr: 8734 case Builtin::BI__builtin_char_memchr: 8735 // memchr compares by converting both sides to unsigned char. That's also 8736 // correct for strchr if we get this far (to cope with plain char being 8737 // unsigned in the strchr case). 8738 DesiredVal = Desired.trunc(Info.Ctx.getCharWidth()).getZExtValue(); 8739 break; 8740 8741 case Builtin::BIwcschr: 8742 case Builtin::BI__builtin_wcschr: 8743 StopAtNull = true; 8744 LLVM_FALLTHROUGH; 8745 case Builtin::BIwmemchr: 8746 case Builtin::BI__builtin_wmemchr: 8747 // wcschr and wmemchr are given a wchar_t to look for. Just use it. 8748 DesiredVal = Desired.getZExtValue(); 8749 break; 8750 } 8751 8752 for (; MaxLength; --MaxLength) { 8753 APValue Char; 8754 if (!handleLValueToRValueConversion(Info, E, CharTy, Result, Char) || 8755 !Char.isInt()) 8756 return false; 8757 if (Char.getInt().getZExtValue() == DesiredVal) 8758 return true; 8759 if (StopAtNull && !Char.getInt()) 8760 break; 8761 if (!HandleLValueArrayAdjustment(Info, E, Result, CharTy, 1)) 8762 return false; 8763 } 8764 // Not found: return nullptr. 8765 return ZeroInitialization(E); 8766 } 8767 8768 case Builtin::BImemcpy: 8769 case Builtin::BImemmove: 8770 case Builtin::BIwmemcpy: 8771 case Builtin::BIwmemmove: 8772 if (Info.getLangOpts().CPlusPlus11) 8773 Info.CCEDiag(E, diag::note_constexpr_invalid_function) 8774 << /*isConstexpr*/0 << /*isConstructor*/0 8775 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'"); 8776 else 8777 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr); 8778 LLVM_FALLTHROUGH; 8779 case Builtin::BI__builtin_memcpy: 8780 case Builtin::BI__builtin_memmove: 8781 case Builtin::BI__builtin_wmemcpy: 8782 case Builtin::BI__builtin_wmemmove: { 8783 bool WChar = BuiltinOp == Builtin::BIwmemcpy || 8784 BuiltinOp == Builtin::BIwmemmove || 8785 BuiltinOp == Builtin::BI__builtin_wmemcpy || 8786 BuiltinOp == Builtin::BI__builtin_wmemmove; 8787 bool Move = BuiltinOp == Builtin::BImemmove || 8788 BuiltinOp == Builtin::BIwmemmove || 8789 BuiltinOp == Builtin::BI__builtin_memmove || 8790 BuiltinOp == Builtin::BI__builtin_wmemmove; 8791 8792 // The result of mem* is the first argument. 8793 if (!Visit(E->getArg(0))) 8794 return false; 8795 LValue Dest = Result; 8796 8797 LValue Src; 8798 if (!EvaluatePointer(E->getArg(1), Src, Info)) 8799 return false; 8800 8801 APSInt N; 8802 if (!EvaluateInteger(E->getArg(2), N, Info)) 8803 return false; 8804 assert(!N.isSigned() && "memcpy and friends take an unsigned size"); 8805 8806 // If the size is zero, we treat this as always being a valid no-op. 8807 // (Even if one of the src and dest pointers is null.) 8808 if (!N) 8809 return true; 8810 8811 // Otherwise, if either of the operands is null, we can't proceed. Don't 8812 // try to determine the type of the copied objects, because there aren't 8813 // any. 8814 if (!Src.Base || !Dest.Base) { 8815 APValue Val; 8816 (!Src.Base ? Src : Dest).moveInto(Val); 8817 Info.FFDiag(E, diag::note_constexpr_memcpy_null) 8818 << Move << WChar << !!Src.Base 8819 << Val.getAsString(Info.Ctx, E->getArg(0)->getType()); 8820 return false; 8821 } 8822 if (Src.Designator.Invalid || Dest.Designator.Invalid) 8823 return false; 8824 8825 // We require that Src and Dest are both pointers to arrays of 8826 // trivially-copyable type. (For the wide version, the designator will be 8827 // invalid if the designated object is not a wchar_t.) 8828 QualType T = Dest.Designator.getType(Info.Ctx); 8829 QualType SrcT = Src.Designator.getType(Info.Ctx); 8830 if (!Info.Ctx.hasSameUnqualifiedType(T, SrcT)) { 8831 // FIXME: Consider using our bit_cast implementation to support this. 8832 Info.FFDiag(E, diag::note_constexpr_memcpy_type_pun) << Move << SrcT << T; 8833 return false; 8834 } 8835 if (T->isIncompleteType()) { 8836 Info.FFDiag(E, diag::note_constexpr_memcpy_incomplete_type) << Move << T; 8837 return false; 8838 } 8839 if (!T.isTriviallyCopyableType(Info.Ctx)) { 8840 Info.FFDiag(E, diag::note_constexpr_memcpy_nontrivial) << Move << T; 8841 return false; 8842 } 8843 8844 // Figure out how many T's we're copying. 8845 uint64_t TSize = Info.Ctx.getTypeSizeInChars(T).getQuantity(); 8846 if (!WChar) { 8847 uint64_t Remainder; 8848 llvm::APInt OrigN = N; 8849 llvm::APInt::udivrem(OrigN, TSize, N, Remainder); 8850 if (Remainder) { 8851 Info.FFDiag(E, diag::note_constexpr_memcpy_unsupported) 8852 << Move << WChar << 0 << T << OrigN.toString(10, /*Signed*/false) 8853 << (unsigned)TSize; 8854 return false; 8855 } 8856 } 8857 8858 // Check that the copying will remain within the arrays, just so that we 8859 // can give a more meaningful diagnostic. This implicitly also checks that 8860 // N fits into 64 bits. 8861 uint64_t RemainingSrcSize = Src.Designator.validIndexAdjustments().second; 8862 uint64_t RemainingDestSize = Dest.Designator.validIndexAdjustments().second; 8863 if (N.ugt(RemainingSrcSize) || N.ugt(RemainingDestSize)) { 8864 Info.FFDiag(E, diag::note_constexpr_memcpy_unsupported) 8865 << Move << WChar << (N.ugt(RemainingSrcSize) ? 1 : 2) << T 8866 << N.toString(10, /*Signed*/false); 8867 return false; 8868 } 8869 uint64_t NElems = N.getZExtValue(); 8870 uint64_t NBytes = NElems * TSize; 8871 8872 // Check for overlap. 8873 int Direction = 1; 8874 if (HasSameBase(Src, Dest)) { 8875 uint64_t SrcOffset = Src.getLValueOffset().getQuantity(); 8876 uint64_t DestOffset = Dest.getLValueOffset().getQuantity(); 8877 if (DestOffset >= SrcOffset && DestOffset - SrcOffset < NBytes) { 8878 // Dest is inside the source region. 8879 if (!Move) { 8880 Info.FFDiag(E, diag::note_constexpr_memcpy_overlap) << WChar; 8881 return false; 8882 } 8883 // For memmove and friends, copy backwards. 8884 if (!HandleLValueArrayAdjustment(Info, E, Src, T, NElems - 1) || 8885 !HandleLValueArrayAdjustment(Info, E, Dest, T, NElems - 1)) 8886 return false; 8887 Direction = -1; 8888 } else if (!Move && SrcOffset >= DestOffset && 8889 SrcOffset - DestOffset < NBytes) { 8890 // Src is inside the destination region for memcpy: invalid. 8891 Info.FFDiag(E, diag::note_constexpr_memcpy_overlap) << WChar; 8892 return false; 8893 } 8894 } 8895 8896 while (true) { 8897 APValue Val; 8898 // FIXME: Set WantObjectRepresentation to true if we're copying a 8899 // char-like type? 8900 if (!handleLValueToRValueConversion(Info, E, T, Src, Val) || 8901 !handleAssignment(Info, E, Dest, T, Val)) 8902 return false; 8903 // Do not iterate past the last element; if we're copying backwards, that 8904 // might take us off the start of the array. 8905 if (--NElems == 0) 8906 return true; 8907 if (!HandleLValueArrayAdjustment(Info, E, Src, T, Direction) || 8908 !HandleLValueArrayAdjustment(Info, E, Dest, T, Direction)) 8909 return false; 8910 } 8911 } 8912 8913 default: 8914 break; 8915 } 8916 8917 return visitNonBuiltinCallExpr(E); 8918 } 8919 8920 static bool EvaluateArrayNewInitList(EvalInfo &Info, LValue &This, 8921 APValue &Result, const InitListExpr *ILE, 8922 QualType AllocType); 8923 static bool EvaluateArrayNewConstructExpr(EvalInfo &Info, LValue &This, 8924 APValue &Result, 8925 const CXXConstructExpr *CCE, 8926 QualType AllocType); 8927 8928 bool PointerExprEvaluator::VisitCXXNewExpr(const CXXNewExpr *E) { 8929 if (!Info.getLangOpts().CPlusPlus20) 8930 Info.CCEDiag(E, diag::note_constexpr_new); 8931 8932 // We cannot speculatively evaluate a delete expression. 8933 if (Info.SpeculativeEvaluationDepth) 8934 return false; 8935 8936 FunctionDecl *OperatorNew = E->getOperatorNew(); 8937 8938 bool IsNothrow = false; 8939 bool IsPlacement = false; 8940 if (OperatorNew->isReservedGlobalPlacementOperator() && 8941 Info.CurrentCall->isStdFunction() && !E->isArray()) { 8942 // FIXME Support array placement new. 8943 assert(E->getNumPlacementArgs() == 1); 8944 if (!EvaluatePointer(E->getPlacementArg(0), Result, Info)) 8945 return false; 8946 if (Result.Designator.Invalid) 8947 return false; 8948 IsPlacement = true; 8949 } else if (!OperatorNew->isReplaceableGlobalAllocationFunction()) { 8950 Info.FFDiag(E, diag::note_constexpr_new_non_replaceable) 8951 << isa<CXXMethodDecl>(OperatorNew) << OperatorNew; 8952 return false; 8953 } else if (E->getNumPlacementArgs()) { 8954 // The only new-placement list we support is of the form (std::nothrow). 8955 // 8956 // FIXME: There is no restriction on this, but it's not clear that any 8957 // other form makes any sense. We get here for cases such as: 8958 // 8959 // new (std::align_val_t{N}) X(int) 8960 // 8961 // (which should presumably be valid only if N is a multiple of 8962 // alignof(int), and in any case can't be deallocated unless N is 8963 // alignof(X) and X has new-extended alignment). 8964 if (E->getNumPlacementArgs() != 1 || 8965 !E->getPlacementArg(0)->getType()->isNothrowT()) 8966 return Error(E, diag::note_constexpr_new_placement); 8967 8968 LValue Nothrow; 8969 if (!EvaluateLValue(E->getPlacementArg(0), Nothrow, Info)) 8970 return false; 8971 IsNothrow = true; 8972 } 8973 8974 const Expr *Init = E->getInitializer(); 8975 const InitListExpr *ResizedArrayILE = nullptr; 8976 const CXXConstructExpr *ResizedArrayCCE = nullptr; 8977 bool ValueInit = false; 8978 8979 QualType AllocType = E->getAllocatedType(); 8980 if (Optional<const Expr*> ArraySize = E->getArraySize()) { 8981 const Expr *Stripped = *ArraySize; 8982 for (; auto *ICE = dyn_cast<ImplicitCastExpr>(Stripped); 8983 Stripped = ICE->getSubExpr()) 8984 if (ICE->getCastKind() != CK_NoOp && 8985 ICE->getCastKind() != CK_IntegralCast) 8986 break; 8987 8988 llvm::APSInt ArrayBound; 8989 if (!EvaluateInteger(Stripped, ArrayBound, Info)) 8990 return false; 8991 8992 // C++ [expr.new]p9: 8993 // The expression is erroneous if: 8994 // -- [...] its value before converting to size_t [or] applying the 8995 // second standard conversion sequence is less than zero 8996 if (ArrayBound.isSigned() && ArrayBound.isNegative()) { 8997 if (IsNothrow) 8998 return ZeroInitialization(E); 8999 9000 Info.FFDiag(*ArraySize, diag::note_constexpr_new_negative) 9001 << ArrayBound << (*ArraySize)->getSourceRange(); 9002 return false; 9003 } 9004 9005 // -- its value is such that the size of the allocated object would 9006 // exceed the implementation-defined limit 9007 if (ConstantArrayType::getNumAddressingBits(Info.Ctx, AllocType, 9008 ArrayBound) > 9009 ConstantArrayType::getMaxSizeBits(Info.Ctx)) { 9010 if (IsNothrow) 9011 return ZeroInitialization(E); 9012 9013 Info.FFDiag(*ArraySize, diag::note_constexpr_new_too_large) 9014 << ArrayBound << (*ArraySize)->getSourceRange(); 9015 return false; 9016 } 9017 9018 // -- the new-initializer is a braced-init-list and the number of 9019 // array elements for which initializers are provided [...] 9020 // exceeds the number of elements to initialize 9021 if (!Init) { 9022 // No initialization is performed. 9023 } else if (isa<CXXScalarValueInitExpr>(Init) || 9024 isa<ImplicitValueInitExpr>(Init)) { 9025 ValueInit = true; 9026 } else if (auto *CCE = dyn_cast<CXXConstructExpr>(Init)) { 9027 ResizedArrayCCE = CCE; 9028 } else { 9029 auto *CAT = Info.Ctx.getAsConstantArrayType(Init->getType()); 9030 assert(CAT && "unexpected type for array initializer"); 9031 9032 unsigned Bits = 9033 std::max(CAT->getSize().getBitWidth(), ArrayBound.getBitWidth()); 9034 llvm::APInt InitBound = CAT->getSize().zextOrSelf(Bits); 9035 llvm::APInt AllocBound = ArrayBound.zextOrSelf(Bits); 9036 if (InitBound.ugt(AllocBound)) { 9037 if (IsNothrow) 9038 return ZeroInitialization(E); 9039 9040 Info.FFDiag(*ArraySize, diag::note_constexpr_new_too_small) 9041 << AllocBound.toString(10, /*Signed=*/false) 9042 << InitBound.toString(10, /*Signed=*/false) 9043 << (*ArraySize)->getSourceRange(); 9044 return false; 9045 } 9046 9047 // If the sizes differ, we must have an initializer list, and we need 9048 // special handling for this case when we initialize. 9049 if (InitBound != AllocBound) 9050 ResizedArrayILE = cast<InitListExpr>(Init); 9051 } 9052 9053 AllocType = Info.Ctx.getConstantArrayType(AllocType, ArrayBound, nullptr, 9054 ArrayType::Normal, 0); 9055 } else { 9056 assert(!AllocType->isArrayType() && 9057 "array allocation with non-array new"); 9058 } 9059 9060 APValue *Val; 9061 if (IsPlacement) { 9062 AccessKinds AK = AK_Construct; 9063 struct FindObjectHandler { 9064 EvalInfo &Info; 9065 const Expr *E; 9066 QualType AllocType; 9067 const AccessKinds AccessKind; 9068 APValue *Value; 9069 9070 typedef bool result_type; 9071 bool failed() { return false; } 9072 bool found(APValue &Subobj, QualType SubobjType) { 9073 // FIXME: Reject the cases where [basic.life]p8 would not permit the 9074 // old name of the object to be used to name the new object. 9075 if (!Info.Ctx.hasSameUnqualifiedType(SubobjType, AllocType)) { 9076 Info.FFDiag(E, diag::note_constexpr_placement_new_wrong_type) << 9077 SubobjType << AllocType; 9078 return false; 9079 } 9080 Value = &Subobj; 9081 return true; 9082 } 9083 bool found(APSInt &Value, QualType SubobjType) { 9084 Info.FFDiag(E, diag::note_constexpr_construct_complex_elem); 9085 return false; 9086 } 9087 bool found(APFloat &Value, QualType SubobjType) { 9088 Info.FFDiag(E, diag::note_constexpr_construct_complex_elem); 9089 return false; 9090 } 9091 } Handler = {Info, E, AllocType, AK, nullptr}; 9092 9093 CompleteObject Obj = findCompleteObject(Info, E, AK, Result, AllocType); 9094 if (!Obj || !findSubobject(Info, E, Obj, Result.Designator, Handler)) 9095 return false; 9096 9097 Val = Handler.Value; 9098 9099 // [basic.life]p1: 9100 // The lifetime of an object o of type T ends when [...] the storage 9101 // which the object occupies is [...] reused by an object that is not 9102 // nested within o (6.6.2). 9103 *Val = APValue(); 9104 } else { 9105 // Perform the allocation and obtain a pointer to the resulting object. 9106 Val = Info.createHeapAlloc(E, AllocType, Result); 9107 if (!Val) 9108 return false; 9109 } 9110 9111 if (ValueInit) { 9112 ImplicitValueInitExpr VIE(AllocType); 9113 if (!EvaluateInPlace(*Val, Info, Result, &VIE)) 9114 return false; 9115 } else if (ResizedArrayILE) { 9116 if (!EvaluateArrayNewInitList(Info, Result, *Val, ResizedArrayILE, 9117 AllocType)) 9118 return false; 9119 } else if (ResizedArrayCCE) { 9120 if (!EvaluateArrayNewConstructExpr(Info, Result, *Val, ResizedArrayCCE, 9121 AllocType)) 9122 return false; 9123 } else if (Init) { 9124 if (!EvaluateInPlace(*Val, Info, Result, Init)) 9125 return false; 9126 } else if (!getDefaultInitValue(AllocType, *Val)) { 9127 return false; 9128 } 9129 9130 // Array new returns a pointer to the first element, not a pointer to the 9131 // array. 9132 if (auto *AT = AllocType->getAsArrayTypeUnsafe()) 9133 Result.addArray(Info, E, cast<ConstantArrayType>(AT)); 9134 9135 return true; 9136 } 9137 //===----------------------------------------------------------------------===// 9138 // Member Pointer Evaluation 9139 //===----------------------------------------------------------------------===// 9140 9141 namespace { 9142 class MemberPointerExprEvaluator 9143 : public ExprEvaluatorBase<MemberPointerExprEvaluator> { 9144 MemberPtr &Result; 9145 9146 bool Success(const ValueDecl *D) { 9147 Result = MemberPtr(D); 9148 return true; 9149 } 9150 public: 9151 9152 MemberPointerExprEvaluator(EvalInfo &Info, MemberPtr &Result) 9153 : ExprEvaluatorBaseTy(Info), Result(Result) {} 9154 9155 bool Success(const APValue &V, const Expr *E) { 9156 Result.setFrom(V); 9157 return true; 9158 } 9159 bool ZeroInitialization(const Expr *E) { 9160 return Success((const ValueDecl*)nullptr); 9161 } 9162 9163 bool VisitCastExpr(const CastExpr *E); 9164 bool VisitUnaryAddrOf(const UnaryOperator *E); 9165 }; 9166 } // end anonymous namespace 9167 9168 static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result, 9169 EvalInfo &Info) { 9170 assert(E->isRValue() && E->getType()->isMemberPointerType()); 9171 return MemberPointerExprEvaluator(Info, Result).Visit(E); 9172 } 9173 9174 bool MemberPointerExprEvaluator::VisitCastExpr(const CastExpr *E) { 9175 switch (E->getCastKind()) { 9176 default: 9177 return ExprEvaluatorBaseTy::VisitCastExpr(E); 9178 9179 case CK_NullToMemberPointer: 9180 VisitIgnoredValue(E->getSubExpr()); 9181 return ZeroInitialization(E); 9182 9183 case CK_BaseToDerivedMemberPointer: { 9184 if (!Visit(E->getSubExpr())) 9185 return false; 9186 if (E->path_empty()) 9187 return true; 9188 // Base-to-derived member pointer casts store the path in derived-to-base 9189 // order, so iterate backwards. The CXXBaseSpecifier also provides us with 9190 // the wrong end of the derived->base arc, so stagger the path by one class. 9191 typedef std::reverse_iterator<CastExpr::path_const_iterator> ReverseIter; 9192 for (ReverseIter PathI(E->path_end() - 1), PathE(E->path_begin()); 9193 PathI != PathE; ++PathI) { 9194 assert(!(*PathI)->isVirtual() && "memptr cast through vbase"); 9195 const CXXRecordDecl *Derived = (*PathI)->getType()->getAsCXXRecordDecl(); 9196 if (!Result.castToDerived(Derived)) 9197 return Error(E); 9198 } 9199 const Type *FinalTy = E->getType()->castAs<MemberPointerType>()->getClass(); 9200 if (!Result.castToDerived(FinalTy->getAsCXXRecordDecl())) 9201 return Error(E); 9202 return true; 9203 } 9204 9205 case CK_DerivedToBaseMemberPointer: 9206 if (!Visit(E->getSubExpr())) 9207 return false; 9208 for (CastExpr::path_const_iterator PathI = E->path_begin(), 9209 PathE = E->path_end(); PathI != PathE; ++PathI) { 9210 assert(!(*PathI)->isVirtual() && "memptr cast through vbase"); 9211 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl(); 9212 if (!Result.castToBase(Base)) 9213 return Error(E); 9214 } 9215 return true; 9216 } 9217 } 9218 9219 bool MemberPointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) { 9220 // C++11 [expr.unary.op]p3 has very strict rules on how the address of a 9221 // member can be formed. 9222 return Success(cast<DeclRefExpr>(E->getSubExpr())->getDecl()); 9223 } 9224 9225 //===----------------------------------------------------------------------===// 9226 // Record Evaluation 9227 //===----------------------------------------------------------------------===// 9228 9229 namespace { 9230 class RecordExprEvaluator 9231 : public ExprEvaluatorBase<RecordExprEvaluator> { 9232 const LValue &This; 9233 APValue &Result; 9234 public: 9235 9236 RecordExprEvaluator(EvalInfo &info, const LValue &This, APValue &Result) 9237 : ExprEvaluatorBaseTy(info), This(This), Result(Result) {} 9238 9239 bool Success(const APValue &V, const Expr *E) { 9240 Result = V; 9241 return true; 9242 } 9243 bool ZeroInitialization(const Expr *E) { 9244 return ZeroInitialization(E, E->getType()); 9245 } 9246 bool ZeroInitialization(const Expr *E, QualType T); 9247 9248 bool VisitCallExpr(const CallExpr *E) { 9249 return handleCallExpr(E, Result, &This); 9250 } 9251 bool VisitCastExpr(const CastExpr *E); 9252 bool VisitInitListExpr(const InitListExpr *E); 9253 bool VisitCXXConstructExpr(const CXXConstructExpr *E) { 9254 return VisitCXXConstructExpr(E, E->getType()); 9255 } 9256 bool VisitLambdaExpr(const LambdaExpr *E); 9257 bool VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *E); 9258 bool VisitCXXConstructExpr(const CXXConstructExpr *E, QualType T); 9259 bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E); 9260 bool VisitBinCmp(const BinaryOperator *E); 9261 }; 9262 } 9263 9264 /// Perform zero-initialization on an object of non-union class type. 9265 /// C++11 [dcl.init]p5: 9266 /// To zero-initialize an object or reference of type T means: 9267 /// [...] 9268 /// -- if T is a (possibly cv-qualified) non-union class type, 9269 /// each non-static data member and each base-class subobject is 9270 /// zero-initialized 9271 static bool HandleClassZeroInitialization(EvalInfo &Info, const Expr *E, 9272 const RecordDecl *RD, 9273 const LValue &This, APValue &Result) { 9274 assert(!RD->isUnion() && "Expected non-union class type"); 9275 const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD); 9276 Result = APValue(APValue::UninitStruct(), CD ? CD->getNumBases() : 0, 9277 std::distance(RD->field_begin(), RD->field_end())); 9278 9279 if (RD->isInvalidDecl()) return false; 9280 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); 9281 9282 if (CD) { 9283 unsigned Index = 0; 9284 for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(), 9285 End = CD->bases_end(); I != End; ++I, ++Index) { 9286 const CXXRecordDecl *Base = I->getType()->getAsCXXRecordDecl(); 9287 LValue Subobject = This; 9288 if (!HandleLValueDirectBase(Info, E, Subobject, CD, Base, &Layout)) 9289 return false; 9290 if (!HandleClassZeroInitialization(Info, E, Base, Subobject, 9291 Result.getStructBase(Index))) 9292 return false; 9293 } 9294 } 9295 9296 for (const auto *I : RD->fields()) { 9297 // -- if T is a reference type, no initialization is performed. 9298 if (I->getType()->isReferenceType()) 9299 continue; 9300 9301 LValue Subobject = This; 9302 if (!HandleLValueMember(Info, E, Subobject, I, &Layout)) 9303 return false; 9304 9305 ImplicitValueInitExpr VIE(I->getType()); 9306 if (!EvaluateInPlace( 9307 Result.getStructField(I->getFieldIndex()), Info, Subobject, &VIE)) 9308 return false; 9309 } 9310 9311 return true; 9312 } 9313 9314 bool RecordExprEvaluator::ZeroInitialization(const Expr *E, QualType T) { 9315 const RecordDecl *RD = T->castAs<RecordType>()->getDecl(); 9316 if (RD->isInvalidDecl()) return false; 9317 if (RD->isUnion()) { 9318 // C++11 [dcl.init]p5: If T is a (possibly cv-qualified) union type, the 9319 // object's first non-static named data member is zero-initialized 9320 RecordDecl::field_iterator I = RD->field_begin(); 9321 if (I == RD->field_end()) { 9322 Result = APValue((const FieldDecl*)nullptr); 9323 return true; 9324 } 9325 9326 LValue Subobject = This; 9327 if (!HandleLValueMember(Info, E, Subobject, *I)) 9328 return false; 9329 Result = APValue(*I); 9330 ImplicitValueInitExpr VIE(I->getType()); 9331 return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, &VIE); 9332 } 9333 9334 if (isa<CXXRecordDecl>(RD) && cast<CXXRecordDecl>(RD)->getNumVBases()) { 9335 Info.FFDiag(E, diag::note_constexpr_virtual_base) << RD; 9336 return false; 9337 } 9338 9339 return HandleClassZeroInitialization(Info, E, RD, This, Result); 9340 } 9341 9342 bool RecordExprEvaluator::VisitCastExpr(const CastExpr *E) { 9343 switch (E->getCastKind()) { 9344 default: 9345 return ExprEvaluatorBaseTy::VisitCastExpr(E); 9346 9347 case CK_ConstructorConversion: 9348 return Visit(E->getSubExpr()); 9349 9350 case CK_DerivedToBase: 9351 case CK_UncheckedDerivedToBase: { 9352 APValue DerivedObject; 9353 if (!Evaluate(DerivedObject, Info, E->getSubExpr())) 9354 return false; 9355 if (!DerivedObject.isStruct()) 9356 return Error(E->getSubExpr()); 9357 9358 // Derived-to-base rvalue conversion: just slice off the derived part. 9359 APValue *Value = &DerivedObject; 9360 const CXXRecordDecl *RD = E->getSubExpr()->getType()->getAsCXXRecordDecl(); 9361 for (CastExpr::path_const_iterator PathI = E->path_begin(), 9362 PathE = E->path_end(); PathI != PathE; ++PathI) { 9363 assert(!(*PathI)->isVirtual() && "record rvalue with virtual base"); 9364 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl(); 9365 Value = &Value->getStructBase(getBaseIndex(RD, Base)); 9366 RD = Base; 9367 } 9368 Result = *Value; 9369 return true; 9370 } 9371 } 9372 } 9373 9374 bool RecordExprEvaluator::VisitInitListExpr(const InitListExpr *E) { 9375 if (E->isTransparent()) 9376 return Visit(E->getInit(0)); 9377 9378 const RecordDecl *RD = E->getType()->castAs<RecordType>()->getDecl(); 9379 if (RD->isInvalidDecl()) return false; 9380 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); 9381 auto *CXXRD = dyn_cast<CXXRecordDecl>(RD); 9382 9383 EvalInfo::EvaluatingConstructorRAII EvalObj( 9384 Info, 9385 ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries}, 9386 CXXRD && CXXRD->getNumBases()); 9387 9388 if (RD->isUnion()) { 9389 const FieldDecl *Field = E->getInitializedFieldInUnion(); 9390 Result = APValue(Field); 9391 if (!Field) 9392 return true; 9393 9394 // If the initializer list for a union does not contain any elements, the 9395 // first element of the union is value-initialized. 9396 // FIXME: The element should be initialized from an initializer list. 9397 // Is this difference ever observable for initializer lists which 9398 // we don't build? 9399 ImplicitValueInitExpr VIE(Field->getType()); 9400 const Expr *InitExpr = E->getNumInits() ? E->getInit(0) : &VIE; 9401 9402 LValue Subobject = This; 9403 if (!HandleLValueMember(Info, InitExpr, Subobject, Field, &Layout)) 9404 return false; 9405 9406 // Temporarily override This, in case there's a CXXDefaultInitExpr in here. 9407 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This, 9408 isa<CXXDefaultInitExpr>(InitExpr)); 9409 9410 return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, InitExpr); 9411 } 9412 9413 if (!Result.hasValue()) 9414 Result = APValue(APValue::UninitStruct(), CXXRD ? CXXRD->getNumBases() : 0, 9415 std::distance(RD->field_begin(), RD->field_end())); 9416 unsigned ElementNo = 0; 9417 bool Success = true; 9418 9419 // Initialize base classes. 9420 if (CXXRD && CXXRD->getNumBases()) { 9421 for (const auto &Base : CXXRD->bases()) { 9422 assert(ElementNo < E->getNumInits() && "missing init for base class"); 9423 const Expr *Init = E->getInit(ElementNo); 9424 9425 LValue Subobject = This; 9426 if (!HandleLValueBase(Info, Init, Subobject, CXXRD, &Base)) 9427 return false; 9428 9429 APValue &FieldVal = Result.getStructBase(ElementNo); 9430 if (!EvaluateInPlace(FieldVal, Info, Subobject, Init)) { 9431 if (!Info.noteFailure()) 9432 return false; 9433 Success = false; 9434 } 9435 ++ElementNo; 9436 } 9437 9438 EvalObj.finishedConstructingBases(); 9439 } 9440 9441 // Initialize members. 9442 for (const auto *Field : RD->fields()) { 9443 // Anonymous bit-fields are not considered members of the class for 9444 // purposes of aggregate initialization. 9445 if (Field->isUnnamedBitfield()) 9446 continue; 9447 9448 LValue Subobject = This; 9449 9450 bool HaveInit = ElementNo < E->getNumInits(); 9451 9452 // FIXME: Diagnostics here should point to the end of the initializer 9453 // list, not the start. 9454 if (!HandleLValueMember(Info, HaveInit ? E->getInit(ElementNo) : E, 9455 Subobject, Field, &Layout)) 9456 return false; 9457 9458 // Perform an implicit value-initialization for members beyond the end of 9459 // the initializer list. 9460 ImplicitValueInitExpr VIE(HaveInit ? Info.Ctx.IntTy : Field->getType()); 9461 const Expr *Init = HaveInit ? E->getInit(ElementNo++) : &VIE; 9462 9463 // Temporarily override This, in case there's a CXXDefaultInitExpr in here. 9464 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This, 9465 isa<CXXDefaultInitExpr>(Init)); 9466 9467 APValue &FieldVal = Result.getStructField(Field->getFieldIndex()); 9468 if (!EvaluateInPlace(FieldVal, Info, Subobject, Init) || 9469 (Field->isBitField() && !truncateBitfieldValue(Info, Init, 9470 FieldVal, Field))) { 9471 if (!Info.noteFailure()) 9472 return false; 9473 Success = false; 9474 } 9475 } 9476 9477 EvalObj.finishedConstructingFields(); 9478 9479 return Success; 9480 } 9481 9482 bool RecordExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E, 9483 QualType T) { 9484 // Note that E's type is not necessarily the type of our class here; we might 9485 // be initializing an array element instead. 9486 const CXXConstructorDecl *FD = E->getConstructor(); 9487 if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl()) return false; 9488 9489 bool ZeroInit = E->requiresZeroInitialization(); 9490 if (CheckTrivialDefaultConstructor(Info, E->getExprLoc(), FD, ZeroInit)) { 9491 // If we've already performed zero-initialization, we're already done. 9492 if (Result.hasValue()) 9493 return true; 9494 9495 if (ZeroInit) 9496 return ZeroInitialization(E, T); 9497 9498 return getDefaultInitValue(T, Result); 9499 } 9500 9501 const FunctionDecl *Definition = nullptr; 9502 auto Body = FD->getBody(Definition); 9503 9504 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body)) 9505 return false; 9506 9507 // Avoid materializing a temporary for an elidable copy/move constructor. 9508 if (E->isElidable() && !ZeroInit) 9509 if (const MaterializeTemporaryExpr *ME 9510 = dyn_cast<MaterializeTemporaryExpr>(E->getArg(0))) 9511 return Visit(ME->getSubExpr()); 9512 9513 if (ZeroInit && !ZeroInitialization(E, T)) 9514 return false; 9515 9516 auto Args = llvm::makeArrayRef(E->getArgs(), E->getNumArgs()); 9517 return HandleConstructorCall(E, This, Args, 9518 cast<CXXConstructorDecl>(Definition), Info, 9519 Result); 9520 } 9521 9522 bool RecordExprEvaluator::VisitCXXInheritedCtorInitExpr( 9523 const CXXInheritedCtorInitExpr *E) { 9524 if (!Info.CurrentCall) { 9525 assert(Info.checkingPotentialConstantExpression()); 9526 return false; 9527 } 9528 9529 const CXXConstructorDecl *FD = E->getConstructor(); 9530 if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl()) 9531 return false; 9532 9533 const FunctionDecl *Definition = nullptr; 9534 auto Body = FD->getBody(Definition); 9535 9536 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body)) 9537 return false; 9538 9539 return HandleConstructorCall(E, This, Info.CurrentCall->Arguments, 9540 cast<CXXConstructorDecl>(Definition), Info, 9541 Result); 9542 } 9543 9544 bool RecordExprEvaluator::VisitCXXStdInitializerListExpr( 9545 const CXXStdInitializerListExpr *E) { 9546 const ConstantArrayType *ArrayType = 9547 Info.Ctx.getAsConstantArrayType(E->getSubExpr()->getType()); 9548 9549 LValue Array; 9550 if (!EvaluateLValue(E->getSubExpr(), Array, Info)) 9551 return false; 9552 9553 // Get a pointer to the first element of the array. 9554 Array.addArray(Info, E, ArrayType); 9555 9556 auto InvalidType = [&] { 9557 Info.FFDiag(E, diag::note_constexpr_unsupported_layout) 9558 << E->getType(); 9559 return false; 9560 }; 9561 9562 // FIXME: Perform the checks on the field types in SemaInit. 9563 RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl(); 9564 RecordDecl::field_iterator Field = Record->field_begin(); 9565 if (Field == Record->field_end()) 9566 return InvalidType(); 9567 9568 // Start pointer. 9569 if (!Field->getType()->isPointerType() || 9570 !Info.Ctx.hasSameType(Field->getType()->getPointeeType(), 9571 ArrayType->getElementType())) 9572 return InvalidType(); 9573 9574 // FIXME: What if the initializer_list type has base classes, etc? 9575 Result = APValue(APValue::UninitStruct(), 0, 2); 9576 Array.moveInto(Result.getStructField(0)); 9577 9578 if (++Field == Record->field_end()) 9579 return InvalidType(); 9580 9581 if (Field->getType()->isPointerType() && 9582 Info.Ctx.hasSameType(Field->getType()->getPointeeType(), 9583 ArrayType->getElementType())) { 9584 // End pointer. 9585 if (!HandleLValueArrayAdjustment(Info, E, Array, 9586 ArrayType->getElementType(), 9587 ArrayType->getSize().getZExtValue())) 9588 return false; 9589 Array.moveInto(Result.getStructField(1)); 9590 } else if (Info.Ctx.hasSameType(Field->getType(), Info.Ctx.getSizeType())) 9591 // Length. 9592 Result.getStructField(1) = APValue(APSInt(ArrayType->getSize())); 9593 else 9594 return InvalidType(); 9595 9596 if (++Field != Record->field_end()) 9597 return InvalidType(); 9598 9599 return true; 9600 } 9601 9602 bool RecordExprEvaluator::VisitLambdaExpr(const LambdaExpr *E) { 9603 const CXXRecordDecl *ClosureClass = E->getLambdaClass(); 9604 if (ClosureClass->isInvalidDecl()) 9605 return false; 9606 9607 const size_t NumFields = 9608 std::distance(ClosureClass->field_begin(), ClosureClass->field_end()); 9609 9610 assert(NumFields == (size_t)std::distance(E->capture_init_begin(), 9611 E->capture_init_end()) && 9612 "The number of lambda capture initializers should equal the number of " 9613 "fields within the closure type"); 9614 9615 Result = APValue(APValue::UninitStruct(), /*NumBases*/0, NumFields); 9616 // Iterate through all the lambda's closure object's fields and initialize 9617 // them. 9618 auto *CaptureInitIt = E->capture_init_begin(); 9619 const LambdaCapture *CaptureIt = ClosureClass->captures_begin(); 9620 bool Success = true; 9621 for (const auto *Field : ClosureClass->fields()) { 9622 assert(CaptureInitIt != E->capture_init_end()); 9623 // Get the initializer for this field 9624 Expr *const CurFieldInit = *CaptureInitIt++; 9625 9626 // If there is no initializer, either this is a VLA or an error has 9627 // occurred. 9628 if (!CurFieldInit) 9629 return Error(E); 9630 9631 APValue &FieldVal = Result.getStructField(Field->getFieldIndex()); 9632 if (!EvaluateInPlace(FieldVal, Info, This, CurFieldInit)) { 9633 if (!Info.keepEvaluatingAfterFailure()) 9634 return false; 9635 Success = false; 9636 } 9637 ++CaptureIt; 9638 } 9639 return Success; 9640 } 9641 9642 static bool EvaluateRecord(const Expr *E, const LValue &This, 9643 APValue &Result, EvalInfo &Info) { 9644 assert(E->isRValue() && E->getType()->isRecordType() && 9645 "can't evaluate expression as a record rvalue"); 9646 return RecordExprEvaluator(Info, This, Result).Visit(E); 9647 } 9648 9649 //===----------------------------------------------------------------------===// 9650 // Temporary Evaluation 9651 // 9652 // Temporaries are represented in the AST as rvalues, but generally behave like 9653 // lvalues. The full-object of which the temporary is a subobject is implicitly 9654 // materialized so that a reference can bind to it. 9655 //===----------------------------------------------------------------------===// 9656 namespace { 9657 class TemporaryExprEvaluator 9658 : public LValueExprEvaluatorBase<TemporaryExprEvaluator> { 9659 public: 9660 TemporaryExprEvaluator(EvalInfo &Info, LValue &Result) : 9661 LValueExprEvaluatorBaseTy(Info, Result, false) {} 9662 9663 /// Visit an expression which constructs the value of this temporary. 9664 bool VisitConstructExpr(const Expr *E) { 9665 APValue &Value = 9666 Info.CurrentCall->createTemporary(E, E->getType(), false, Result); 9667 return EvaluateInPlace(Value, Info, Result, E); 9668 } 9669 9670 bool VisitCastExpr(const CastExpr *E) { 9671 switch (E->getCastKind()) { 9672 default: 9673 return LValueExprEvaluatorBaseTy::VisitCastExpr(E); 9674 9675 case CK_ConstructorConversion: 9676 return VisitConstructExpr(E->getSubExpr()); 9677 } 9678 } 9679 bool VisitInitListExpr(const InitListExpr *E) { 9680 return VisitConstructExpr(E); 9681 } 9682 bool VisitCXXConstructExpr(const CXXConstructExpr *E) { 9683 return VisitConstructExpr(E); 9684 } 9685 bool VisitCallExpr(const CallExpr *E) { 9686 return VisitConstructExpr(E); 9687 } 9688 bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E) { 9689 return VisitConstructExpr(E); 9690 } 9691 bool VisitLambdaExpr(const LambdaExpr *E) { 9692 return VisitConstructExpr(E); 9693 } 9694 }; 9695 } // end anonymous namespace 9696 9697 /// Evaluate an expression of record type as a temporary. 9698 static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info) { 9699 assert(E->isRValue() && E->getType()->isRecordType()); 9700 return TemporaryExprEvaluator(Info, Result).Visit(E); 9701 } 9702 9703 //===----------------------------------------------------------------------===// 9704 // Vector Evaluation 9705 //===----------------------------------------------------------------------===// 9706 9707 namespace { 9708 class VectorExprEvaluator 9709 : public ExprEvaluatorBase<VectorExprEvaluator> { 9710 APValue &Result; 9711 public: 9712 9713 VectorExprEvaluator(EvalInfo &info, APValue &Result) 9714 : ExprEvaluatorBaseTy(info), Result(Result) {} 9715 9716 bool Success(ArrayRef<APValue> V, const Expr *E) { 9717 assert(V.size() == E->getType()->castAs<VectorType>()->getNumElements()); 9718 // FIXME: remove this APValue copy. 9719 Result = APValue(V.data(), V.size()); 9720 return true; 9721 } 9722 bool Success(const APValue &V, const Expr *E) { 9723 assert(V.isVector()); 9724 Result = V; 9725 return true; 9726 } 9727 bool ZeroInitialization(const Expr *E); 9728 9729 bool VisitUnaryReal(const UnaryOperator *E) 9730 { return Visit(E->getSubExpr()); } 9731 bool VisitCastExpr(const CastExpr* E); 9732 bool VisitInitListExpr(const InitListExpr *E); 9733 bool VisitUnaryImag(const UnaryOperator *E); 9734 bool VisitBinaryOperator(const BinaryOperator *E); 9735 // FIXME: Missing: unary -, unary ~, conditional operator (for GNU 9736 // conditional select), shufflevector, ExtVectorElementExpr 9737 }; 9738 } // end anonymous namespace 9739 9740 static bool EvaluateVector(const Expr* E, APValue& Result, EvalInfo &Info) { 9741 assert(E->isRValue() && E->getType()->isVectorType() &&"not a vector rvalue"); 9742 return VectorExprEvaluator(Info, Result).Visit(E); 9743 } 9744 9745 bool VectorExprEvaluator::VisitCastExpr(const CastExpr *E) { 9746 const VectorType *VTy = E->getType()->castAs<VectorType>(); 9747 unsigned NElts = VTy->getNumElements(); 9748 9749 const Expr *SE = E->getSubExpr(); 9750 QualType SETy = SE->getType(); 9751 9752 switch (E->getCastKind()) { 9753 case CK_VectorSplat: { 9754 APValue Val = APValue(); 9755 if (SETy->isIntegerType()) { 9756 APSInt IntResult; 9757 if (!EvaluateInteger(SE, IntResult, Info)) 9758 return false; 9759 Val = APValue(std::move(IntResult)); 9760 } else if (SETy->isRealFloatingType()) { 9761 APFloat FloatResult(0.0); 9762 if (!EvaluateFloat(SE, FloatResult, Info)) 9763 return false; 9764 Val = APValue(std::move(FloatResult)); 9765 } else { 9766 return Error(E); 9767 } 9768 9769 // Splat and create vector APValue. 9770 SmallVector<APValue, 4> Elts(NElts, Val); 9771 return Success(Elts, E); 9772 } 9773 case CK_BitCast: { 9774 // Evaluate the operand into an APInt we can extract from. 9775 llvm::APInt SValInt; 9776 if (!EvalAndBitcastToAPInt(Info, SE, SValInt)) 9777 return false; 9778 // Extract the elements 9779 QualType EltTy = VTy->getElementType(); 9780 unsigned EltSize = Info.Ctx.getTypeSize(EltTy); 9781 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian(); 9782 SmallVector<APValue, 4> Elts; 9783 if (EltTy->isRealFloatingType()) { 9784 const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(EltTy); 9785 unsigned FloatEltSize = EltSize; 9786 if (&Sem == &APFloat::x87DoubleExtended()) 9787 FloatEltSize = 80; 9788 for (unsigned i = 0; i < NElts; i++) { 9789 llvm::APInt Elt; 9790 if (BigEndian) 9791 Elt = SValInt.rotl(i*EltSize+FloatEltSize).trunc(FloatEltSize); 9792 else 9793 Elt = SValInt.rotr(i*EltSize).trunc(FloatEltSize); 9794 Elts.push_back(APValue(APFloat(Sem, Elt))); 9795 } 9796 } else if (EltTy->isIntegerType()) { 9797 for (unsigned i = 0; i < NElts; i++) { 9798 llvm::APInt Elt; 9799 if (BigEndian) 9800 Elt = SValInt.rotl(i*EltSize+EltSize).zextOrTrunc(EltSize); 9801 else 9802 Elt = SValInt.rotr(i*EltSize).zextOrTrunc(EltSize); 9803 Elts.push_back(APValue(APSInt(Elt, EltTy->isSignedIntegerType()))); 9804 } 9805 } else { 9806 return Error(E); 9807 } 9808 return Success(Elts, E); 9809 } 9810 default: 9811 return ExprEvaluatorBaseTy::VisitCastExpr(E); 9812 } 9813 } 9814 9815 bool 9816 VectorExprEvaluator::VisitInitListExpr(const InitListExpr *E) { 9817 const VectorType *VT = E->getType()->castAs<VectorType>(); 9818 unsigned NumInits = E->getNumInits(); 9819 unsigned NumElements = VT->getNumElements(); 9820 9821 QualType EltTy = VT->getElementType(); 9822 SmallVector<APValue, 4> Elements; 9823 9824 // The number of initializers can be less than the number of 9825 // vector elements. For OpenCL, this can be due to nested vector 9826 // initialization. For GCC compatibility, missing trailing elements 9827 // should be initialized with zeroes. 9828 unsigned CountInits = 0, CountElts = 0; 9829 while (CountElts < NumElements) { 9830 // Handle nested vector initialization. 9831 if (CountInits < NumInits 9832 && E->getInit(CountInits)->getType()->isVectorType()) { 9833 APValue v; 9834 if (!EvaluateVector(E->getInit(CountInits), v, Info)) 9835 return Error(E); 9836 unsigned vlen = v.getVectorLength(); 9837 for (unsigned j = 0; j < vlen; j++) 9838 Elements.push_back(v.getVectorElt(j)); 9839 CountElts += vlen; 9840 } else if (EltTy->isIntegerType()) { 9841 llvm::APSInt sInt(32); 9842 if (CountInits < NumInits) { 9843 if (!EvaluateInteger(E->getInit(CountInits), sInt, Info)) 9844 return false; 9845 } else // trailing integer zero. 9846 sInt = Info.Ctx.MakeIntValue(0, EltTy); 9847 Elements.push_back(APValue(sInt)); 9848 CountElts++; 9849 } else { 9850 llvm::APFloat f(0.0); 9851 if (CountInits < NumInits) { 9852 if (!EvaluateFloat(E->getInit(CountInits), f, Info)) 9853 return false; 9854 } else // trailing float zero. 9855 f = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy)); 9856 Elements.push_back(APValue(f)); 9857 CountElts++; 9858 } 9859 CountInits++; 9860 } 9861 return Success(Elements, E); 9862 } 9863 9864 bool 9865 VectorExprEvaluator::ZeroInitialization(const Expr *E) { 9866 const auto *VT = E->getType()->castAs<VectorType>(); 9867 QualType EltTy = VT->getElementType(); 9868 APValue ZeroElement; 9869 if (EltTy->isIntegerType()) 9870 ZeroElement = APValue(Info.Ctx.MakeIntValue(0, EltTy)); 9871 else 9872 ZeroElement = 9873 APValue(APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy))); 9874 9875 SmallVector<APValue, 4> Elements(VT->getNumElements(), ZeroElement); 9876 return Success(Elements, E); 9877 } 9878 9879 bool VectorExprEvaluator::VisitUnaryImag(const UnaryOperator *E) { 9880 VisitIgnoredValue(E->getSubExpr()); 9881 return ZeroInitialization(E); 9882 } 9883 9884 bool VectorExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { 9885 BinaryOperatorKind Op = E->getOpcode(); 9886 assert(Op != BO_PtrMemD && Op != BO_PtrMemI && Op != BO_Cmp && 9887 "Operation not supported on vector types"); 9888 9889 if (Op == BO_Comma) 9890 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 9891 9892 Expr *LHS = E->getLHS(); 9893 Expr *RHS = E->getRHS(); 9894 9895 assert(LHS->getType()->isVectorType() && RHS->getType()->isVectorType() && 9896 "Must both be vector types"); 9897 // Checking JUST the types are the same would be fine, except shifts don't 9898 // need to have their types be the same (since you always shift by an int). 9899 assert(LHS->getType()->getAs<VectorType>()->getNumElements() == 9900 E->getType()->getAs<VectorType>()->getNumElements() && 9901 RHS->getType()->getAs<VectorType>()->getNumElements() == 9902 E->getType()->getAs<VectorType>()->getNumElements() && 9903 "All operands must be the same size."); 9904 9905 APValue LHSValue; 9906 APValue RHSValue; 9907 bool LHSOK = Evaluate(LHSValue, Info, LHS); 9908 if (!LHSOK && !Info.noteFailure()) 9909 return false; 9910 if (!Evaluate(RHSValue, Info, RHS) || !LHSOK) 9911 return false; 9912 9913 if (!handleVectorVectorBinOp(Info, E, Op, LHSValue, RHSValue)) 9914 return false; 9915 9916 return Success(LHSValue, E); 9917 } 9918 9919 //===----------------------------------------------------------------------===// 9920 // Array Evaluation 9921 //===----------------------------------------------------------------------===// 9922 9923 namespace { 9924 class ArrayExprEvaluator 9925 : public ExprEvaluatorBase<ArrayExprEvaluator> { 9926 const LValue &This; 9927 APValue &Result; 9928 public: 9929 9930 ArrayExprEvaluator(EvalInfo &Info, const LValue &This, APValue &Result) 9931 : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {} 9932 9933 bool Success(const APValue &V, const Expr *E) { 9934 assert(V.isArray() && "expected array"); 9935 Result = V; 9936 return true; 9937 } 9938 9939 bool ZeroInitialization(const Expr *E) { 9940 const ConstantArrayType *CAT = 9941 Info.Ctx.getAsConstantArrayType(E->getType()); 9942 if (!CAT) { 9943 if (E->getType()->isIncompleteArrayType()) { 9944 // We can be asked to zero-initialize a flexible array member; this 9945 // is represented as an ImplicitValueInitExpr of incomplete array 9946 // type. In this case, the array has zero elements. 9947 Result = APValue(APValue::UninitArray(), 0, 0); 9948 return true; 9949 } 9950 // FIXME: We could handle VLAs here. 9951 return Error(E); 9952 } 9953 9954 Result = APValue(APValue::UninitArray(), 0, 9955 CAT->getSize().getZExtValue()); 9956 if (!Result.hasArrayFiller()) return true; 9957 9958 // Zero-initialize all elements. 9959 LValue Subobject = This; 9960 Subobject.addArray(Info, E, CAT); 9961 ImplicitValueInitExpr VIE(CAT->getElementType()); 9962 return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject, &VIE); 9963 } 9964 9965 bool VisitCallExpr(const CallExpr *E) { 9966 return handleCallExpr(E, Result, &This); 9967 } 9968 bool VisitInitListExpr(const InitListExpr *E, 9969 QualType AllocType = QualType()); 9970 bool VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E); 9971 bool VisitCXXConstructExpr(const CXXConstructExpr *E); 9972 bool VisitCXXConstructExpr(const CXXConstructExpr *E, 9973 const LValue &Subobject, 9974 APValue *Value, QualType Type); 9975 bool VisitStringLiteral(const StringLiteral *E, 9976 QualType AllocType = QualType()) { 9977 expandStringLiteral(Info, E, Result, AllocType); 9978 return true; 9979 } 9980 }; 9981 } // end anonymous namespace 9982 9983 static bool EvaluateArray(const Expr *E, const LValue &This, 9984 APValue &Result, EvalInfo &Info) { 9985 assert(E->isRValue() && E->getType()->isArrayType() && "not an array rvalue"); 9986 return ArrayExprEvaluator(Info, This, Result).Visit(E); 9987 } 9988 9989 static bool EvaluateArrayNewInitList(EvalInfo &Info, LValue &This, 9990 APValue &Result, const InitListExpr *ILE, 9991 QualType AllocType) { 9992 assert(ILE->isRValue() && ILE->getType()->isArrayType() && 9993 "not an array rvalue"); 9994 return ArrayExprEvaluator(Info, This, Result) 9995 .VisitInitListExpr(ILE, AllocType); 9996 } 9997 9998 static bool EvaluateArrayNewConstructExpr(EvalInfo &Info, LValue &This, 9999 APValue &Result, 10000 const CXXConstructExpr *CCE, 10001 QualType AllocType) { 10002 assert(CCE->isRValue() && CCE->getType()->isArrayType() && 10003 "not an array rvalue"); 10004 return ArrayExprEvaluator(Info, This, Result) 10005 .VisitCXXConstructExpr(CCE, This, &Result, AllocType); 10006 } 10007 10008 // Return true iff the given array filler may depend on the element index. 10009 static bool MaybeElementDependentArrayFiller(const Expr *FillerExpr) { 10010 // For now, just allow non-class value-initialization and initialization 10011 // lists comprised of them. 10012 if (isa<ImplicitValueInitExpr>(FillerExpr)) 10013 return false; 10014 if (const InitListExpr *ILE = dyn_cast<InitListExpr>(FillerExpr)) { 10015 for (unsigned I = 0, E = ILE->getNumInits(); I != E; ++I) { 10016 if (MaybeElementDependentArrayFiller(ILE->getInit(I))) 10017 return true; 10018 } 10019 return false; 10020 } 10021 return true; 10022 } 10023 10024 bool ArrayExprEvaluator::VisitInitListExpr(const InitListExpr *E, 10025 QualType AllocType) { 10026 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType( 10027 AllocType.isNull() ? E->getType() : AllocType); 10028 if (!CAT) 10029 return Error(E); 10030 10031 // C++11 [dcl.init.string]p1: A char array [...] can be initialized by [...] 10032 // an appropriately-typed string literal enclosed in braces. 10033 if (E->isStringLiteralInit()) { 10034 auto *SL = dyn_cast<StringLiteral>(E->getInit(0)->IgnoreParens()); 10035 // FIXME: Support ObjCEncodeExpr here once we support it in 10036 // ArrayExprEvaluator generally. 10037 if (!SL) 10038 return Error(E); 10039 return VisitStringLiteral(SL, AllocType); 10040 } 10041 10042 bool Success = true; 10043 10044 assert((!Result.isArray() || Result.getArrayInitializedElts() == 0) && 10045 "zero-initialized array shouldn't have any initialized elts"); 10046 APValue Filler; 10047 if (Result.isArray() && Result.hasArrayFiller()) 10048 Filler = Result.getArrayFiller(); 10049 10050 unsigned NumEltsToInit = E->getNumInits(); 10051 unsigned NumElts = CAT->getSize().getZExtValue(); 10052 const Expr *FillerExpr = E->hasArrayFiller() ? E->getArrayFiller() : nullptr; 10053 10054 // If the initializer might depend on the array index, run it for each 10055 // array element. 10056 if (NumEltsToInit != NumElts && MaybeElementDependentArrayFiller(FillerExpr)) 10057 NumEltsToInit = NumElts; 10058 10059 LLVM_DEBUG(llvm::dbgs() << "The number of elements to initialize: " 10060 << NumEltsToInit << ".\n"); 10061 10062 Result = APValue(APValue::UninitArray(), NumEltsToInit, NumElts); 10063 10064 // If the array was previously zero-initialized, preserve the 10065 // zero-initialized values. 10066 if (Filler.hasValue()) { 10067 for (unsigned I = 0, E = Result.getArrayInitializedElts(); I != E; ++I) 10068 Result.getArrayInitializedElt(I) = Filler; 10069 if (Result.hasArrayFiller()) 10070 Result.getArrayFiller() = Filler; 10071 } 10072 10073 LValue Subobject = This; 10074 Subobject.addArray(Info, E, CAT); 10075 for (unsigned Index = 0; Index != NumEltsToInit; ++Index) { 10076 const Expr *Init = 10077 Index < E->getNumInits() ? E->getInit(Index) : FillerExpr; 10078 if (!EvaluateInPlace(Result.getArrayInitializedElt(Index), 10079 Info, Subobject, Init) || 10080 !HandleLValueArrayAdjustment(Info, Init, Subobject, 10081 CAT->getElementType(), 1)) { 10082 if (!Info.noteFailure()) 10083 return false; 10084 Success = false; 10085 } 10086 } 10087 10088 if (!Result.hasArrayFiller()) 10089 return Success; 10090 10091 // If we get here, we have a trivial filler, which we can just evaluate 10092 // once and splat over the rest of the array elements. 10093 assert(FillerExpr && "no array filler for incomplete init list"); 10094 return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject, 10095 FillerExpr) && Success; 10096 } 10097 10098 bool ArrayExprEvaluator::VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E) { 10099 LValue CommonLV; 10100 if (E->getCommonExpr() && 10101 !Evaluate(Info.CurrentCall->createTemporary( 10102 E->getCommonExpr(), 10103 getStorageType(Info.Ctx, E->getCommonExpr()), false, 10104 CommonLV), 10105 Info, E->getCommonExpr()->getSourceExpr())) 10106 return false; 10107 10108 auto *CAT = cast<ConstantArrayType>(E->getType()->castAsArrayTypeUnsafe()); 10109 10110 uint64_t Elements = CAT->getSize().getZExtValue(); 10111 Result = APValue(APValue::UninitArray(), Elements, Elements); 10112 10113 LValue Subobject = This; 10114 Subobject.addArray(Info, E, CAT); 10115 10116 bool Success = true; 10117 for (EvalInfo::ArrayInitLoopIndex Index(Info); Index != Elements; ++Index) { 10118 if (!EvaluateInPlace(Result.getArrayInitializedElt(Index), 10119 Info, Subobject, E->getSubExpr()) || 10120 !HandleLValueArrayAdjustment(Info, E, Subobject, 10121 CAT->getElementType(), 1)) { 10122 if (!Info.noteFailure()) 10123 return false; 10124 Success = false; 10125 } 10126 } 10127 10128 return Success; 10129 } 10130 10131 bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) { 10132 return VisitCXXConstructExpr(E, This, &Result, E->getType()); 10133 } 10134 10135 bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E, 10136 const LValue &Subobject, 10137 APValue *Value, 10138 QualType Type) { 10139 bool HadZeroInit = Value->hasValue(); 10140 10141 if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(Type)) { 10142 unsigned N = CAT->getSize().getZExtValue(); 10143 10144 // Preserve the array filler if we had prior zero-initialization. 10145 APValue Filler = 10146 HadZeroInit && Value->hasArrayFiller() ? Value->getArrayFiller() 10147 : APValue(); 10148 10149 *Value = APValue(APValue::UninitArray(), N, N); 10150 10151 if (HadZeroInit) 10152 for (unsigned I = 0; I != N; ++I) 10153 Value->getArrayInitializedElt(I) = Filler; 10154 10155 // Initialize the elements. 10156 LValue ArrayElt = Subobject; 10157 ArrayElt.addArray(Info, E, CAT); 10158 for (unsigned I = 0; I != N; ++I) 10159 if (!VisitCXXConstructExpr(E, ArrayElt, &Value->getArrayInitializedElt(I), 10160 CAT->getElementType()) || 10161 !HandleLValueArrayAdjustment(Info, E, ArrayElt, 10162 CAT->getElementType(), 1)) 10163 return false; 10164 10165 return true; 10166 } 10167 10168 if (!Type->isRecordType()) 10169 return Error(E); 10170 10171 return RecordExprEvaluator(Info, Subobject, *Value) 10172 .VisitCXXConstructExpr(E, Type); 10173 } 10174 10175 //===----------------------------------------------------------------------===// 10176 // Integer Evaluation 10177 // 10178 // As a GNU extension, we support casting pointers to sufficiently-wide integer 10179 // types and back in constant folding. Integer values are thus represented 10180 // either as an integer-valued APValue, or as an lvalue-valued APValue. 10181 //===----------------------------------------------------------------------===// 10182 10183 namespace { 10184 class IntExprEvaluator 10185 : public ExprEvaluatorBase<IntExprEvaluator> { 10186 APValue &Result; 10187 public: 10188 IntExprEvaluator(EvalInfo &info, APValue &result) 10189 : ExprEvaluatorBaseTy(info), Result(result) {} 10190 10191 bool Success(const llvm::APSInt &SI, const Expr *E, APValue &Result) { 10192 assert(E->getType()->isIntegralOrEnumerationType() && 10193 "Invalid evaluation result."); 10194 assert(SI.isSigned() == E->getType()->isSignedIntegerOrEnumerationType() && 10195 "Invalid evaluation result."); 10196 assert(SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) && 10197 "Invalid evaluation result."); 10198 Result = APValue(SI); 10199 return true; 10200 } 10201 bool Success(const llvm::APSInt &SI, const Expr *E) { 10202 return Success(SI, E, Result); 10203 } 10204 10205 bool Success(const llvm::APInt &I, const Expr *E, APValue &Result) { 10206 assert(E->getType()->isIntegralOrEnumerationType() && 10207 "Invalid evaluation result."); 10208 assert(I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) && 10209 "Invalid evaluation result."); 10210 Result = APValue(APSInt(I)); 10211 Result.getInt().setIsUnsigned( 10212 E->getType()->isUnsignedIntegerOrEnumerationType()); 10213 return true; 10214 } 10215 bool Success(const llvm::APInt &I, const Expr *E) { 10216 return Success(I, E, Result); 10217 } 10218 10219 bool Success(uint64_t Value, const Expr *E, APValue &Result) { 10220 assert(E->getType()->isIntegralOrEnumerationType() && 10221 "Invalid evaluation result."); 10222 Result = APValue(Info.Ctx.MakeIntValue(Value, E->getType())); 10223 return true; 10224 } 10225 bool Success(uint64_t Value, const Expr *E) { 10226 return Success(Value, E, Result); 10227 } 10228 10229 bool Success(CharUnits Size, const Expr *E) { 10230 return Success(Size.getQuantity(), E); 10231 } 10232 10233 bool Success(const APValue &V, const Expr *E) { 10234 if (V.isLValue() || V.isAddrLabelDiff() || V.isIndeterminate()) { 10235 Result = V; 10236 return true; 10237 } 10238 return Success(V.getInt(), E); 10239 } 10240 10241 bool ZeroInitialization(const Expr *E) { return Success(0, E); } 10242 10243 //===--------------------------------------------------------------------===// 10244 // Visitor Methods 10245 //===--------------------------------------------------------------------===// 10246 10247 bool VisitIntegerLiteral(const IntegerLiteral *E) { 10248 return Success(E->getValue(), E); 10249 } 10250 bool VisitCharacterLiteral(const CharacterLiteral *E) { 10251 return Success(E->getValue(), E); 10252 } 10253 10254 bool CheckReferencedDecl(const Expr *E, const Decl *D); 10255 bool VisitDeclRefExpr(const DeclRefExpr *E) { 10256 if (CheckReferencedDecl(E, E->getDecl())) 10257 return true; 10258 10259 return ExprEvaluatorBaseTy::VisitDeclRefExpr(E); 10260 } 10261 bool VisitMemberExpr(const MemberExpr *E) { 10262 if (CheckReferencedDecl(E, E->getMemberDecl())) { 10263 VisitIgnoredBaseExpression(E->getBase()); 10264 return true; 10265 } 10266 10267 return ExprEvaluatorBaseTy::VisitMemberExpr(E); 10268 } 10269 10270 bool VisitCallExpr(const CallExpr *E); 10271 bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp); 10272 bool VisitBinaryOperator(const BinaryOperator *E); 10273 bool VisitOffsetOfExpr(const OffsetOfExpr *E); 10274 bool VisitUnaryOperator(const UnaryOperator *E); 10275 10276 bool VisitCastExpr(const CastExpr* E); 10277 bool VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E); 10278 10279 bool VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) { 10280 return Success(E->getValue(), E); 10281 } 10282 10283 bool VisitObjCBoolLiteralExpr(const ObjCBoolLiteralExpr *E) { 10284 return Success(E->getValue(), E); 10285 } 10286 10287 bool VisitArrayInitIndexExpr(const ArrayInitIndexExpr *E) { 10288 if (Info.ArrayInitIndex == uint64_t(-1)) { 10289 // We were asked to evaluate this subexpression independent of the 10290 // enclosing ArrayInitLoopExpr. We can't do that. 10291 Info.FFDiag(E); 10292 return false; 10293 } 10294 return Success(Info.ArrayInitIndex, E); 10295 } 10296 10297 // Note, GNU defines __null as an integer, not a pointer. 10298 bool VisitGNUNullExpr(const GNUNullExpr *E) { 10299 return ZeroInitialization(E); 10300 } 10301 10302 bool VisitTypeTraitExpr(const TypeTraitExpr *E) { 10303 return Success(E->getValue(), E); 10304 } 10305 10306 bool VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr *E) { 10307 return Success(E->getValue(), E); 10308 } 10309 10310 bool VisitExpressionTraitExpr(const ExpressionTraitExpr *E) { 10311 return Success(E->getValue(), E); 10312 } 10313 10314 bool VisitUnaryReal(const UnaryOperator *E); 10315 bool VisitUnaryImag(const UnaryOperator *E); 10316 10317 bool VisitCXXNoexceptExpr(const CXXNoexceptExpr *E); 10318 bool VisitSizeOfPackExpr(const SizeOfPackExpr *E); 10319 bool VisitSourceLocExpr(const SourceLocExpr *E); 10320 bool VisitConceptSpecializationExpr(const ConceptSpecializationExpr *E); 10321 bool VisitRequiresExpr(const RequiresExpr *E); 10322 // FIXME: Missing: array subscript of vector, member of vector 10323 }; 10324 10325 class FixedPointExprEvaluator 10326 : public ExprEvaluatorBase<FixedPointExprEvaluator> { 10327 APValue &Result; 10328 10329 public: 10330 FixedPointExprEvaluator(EvalInfo &info, APValue &result) 10331 : ExprEvaluatorBaseTy(info), Result(result) {} 10332 10333 bool Success(const llvm::APInt &I, const Expr *E) { 10334 return Success( 10335 APFixedPoint(I, Info.Ctx.getFixedPointSemantics(E->getType())), E); 10336 } 10337 10338 bool Success(uint64_t Value, const Expr *E) { 10339 return Success( 10340 APFixedPoint(Value, Info.Ctx.getFixedPointSemantics(E->getType())), E); 10341 } 10342 10343 bool Success(const APValue &V, const Expr *E) { 10344 return Success(V.getFixedPoint(), E); 10345 } 10346 10347 bool Success(const APFixedPoint &V, const Expr *E) { 10348 assert(E->getType()->isFixedPointType() && "Invalid evaluation result."); 10349 assert(V.getWidth() == Info.Ctx.getIntWidth(E->getType()) && 10350 "Invalid evaluation result."); 10351 Result = APValue(V); 10352 return true; 10353 } 10354 10355 //===--------------------------------------------------------------------===// 10356 // Visitor Methods 10357 //===--------------------------------------------------------------------===// 10358 10359 bool VisitFixedPointLiteral(const FixedPointLiteral *E) { 10360 return Success(E->getValue(), E); 10361 } 10362 10363 bool VisitCastExpr(const CastExpr *E); 10364 bool VisitUnaryOperator(const UnaryOperator *E); 10365 bool VisitBinaryOperator(const BinaryOperator *E); 10366 }; 10367 } // end anonymous namespace 10368 10369 /// EvaluateIntegerOrLValue - Evaluate an rvalue integral-typed expression, and 10370 /// produce either the integer value or a pointer. 10371 /// 10372 /// GCC has a heinous extension which folds casts between pointer types and 10373 /// pointer-sized integral types. We support this by allowing the evaluation of 10374 /// an integer rvalue to produce a pointer (represented as an lvalue) instead. 10375 /// Some simple arithmetic on such values is supported (they are treated much 10376 /// like char*). 10377 static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result, 10378 EvalInfo &Info) { 10379 assert(E->isRValue() && E->getType()->isIntegralOrEnumerationType()); 10380 return IntExprEvaluator(Info, Result).Visit(E); 10381 } 10382 10383 static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info) { 10384 APValue Val; 10385 if (!EvaluateIntegerOrLValue(E, Val, Info)) 10386 return false; 10387 if (!Val.isInt()) { 10388 // FIXME: It would be better to produce the diagnostic for casting 10389 // a pointer to an integer. 10390 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr); 10391 return false; 10392 } 10393 Result = Val.getInt(); 10394 return true; 10395 } 10396 10397 bool IntExprEvaluator::VisitSourceLocExpr(const SourceLocExpr *E) { 10398 APValue Evaluated = E->EvaluateInContext( 10399 Info.Ctx, Info.CurrentCall->CurSourceLocExprScope.getDefaultExpr()); 10400 return Success(Evaluated, E); 10401 } 10402 10403 static bool EvaluateFixedPoint(const Expr *E, APFixedPoint &Result, 10404 EvalInfo &Info) { 10405 if (E->getType()->isFixedPointType()) { 10406 APValue Val; 10407 if (!FixedPointExprEvaluator(Info, Val).Visit(E)) 10408 return false; 10409 if (!Val.isFixedPoint()) 10410 return false; 10411 10412 Result = Val.getFixedPoint(); 10413 return true; 10414 } 10415 return false; 10416 } 10417 10418 static bool EvaluateFixedPointOrInteger(const Expr *E, APFixedPoint &Result, 10419 EvalInfo &Info) { 10420 if (E->getType()->isIntegerType()) { 10421 auto FXSema = Info.Ctx.getFixedPointSemantics(E->getType()); 10422 APSInt Val; 10423 if (!EvaluateInteger(E, Val, Info)) 10424 return false; 10425 Result = APFixedPoint(Val, FXSema); 10426 return true; 10427 } else if (E->getType()->isFixedPointType()) { 10428 return EvaluateFixedPoint(E, Result, Info); 10429 } 10430 return false; 10431 } 10432 10433 /// Check whether the given declaration can be directly converted to an integral 10434 /// rvalue. If not, no diagnostic is produced; there are other things we can 10435 /// try. 10436 bool IntExprEvaluator::CheckReferencedDecl(const Expr* E, const Decl* D) { 10437 // Enums are integer constant exprs. 10438 if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(D)) { 10439 // Check for signedness/width mismatches between E type and ECD value. 10440 bool SameSign = (ECD->getInitVal().isSigned() 10441 == E->getType()->isSignedIntegerOrEnumerationType()); 10442 bool SameWidth = (ECD->getInitVal().getBitWidth() 10443 == Info.Ctx.getIntWidth(E->getType())); 10444 if (SameSign && SameWidth) 10445 return Success(ECD->getInitVal(), E); 10446 else { 10447 // Get rid of mismatch (otherwise Success assertions will fail) 10448 // by computing a new value matching the type of E. 10449 llvm::APSInt Val = ECD->getInitVal(); 10450 if (!SameSign) 10451 Val.setIsSigned(!ECD->getInitVal().isSigned()); 10452 if (!SameWidth) 10453 Val = Val.extOrTrunc(Info.Ctx.getIntWidth(E->getType())); 10454 return Success(Val, E); 10455 } 10456 } 10457 return false; 10458 } 10459 10460 /// Values returned by __builtin_classify_type, chosen to match the values 10461 /// produced by GCC's builtin. 10462 enum class GCCTypeClass { 10463 None = -1, 10464 Void = 0, 10465 Integer = 1, 10466 // GCC reserves 2 for character types, but instead classifies them as 10467 // integers. 10468 Enum = 3, 10469 Bool = 4, 10470 Pointer = 5, 10471 // GCC reserves 6 for references, but appears to never use it (because 10472 // expressions never have reference type, presumably). 10473 PointerToDataMember = 7, 10474 RealFloat = 8, 10475 Complex = 9, 10476 // GCC reserves 10 for functions, but does not use it since GCC version 6 due 10477 // to decay to pointer. (Prior to version 6 it was only used in C++ mode). 10478 // GCC claims to reserve 11 for pointers to member functions, but *actually* 10479 // uses 12 for that purpose, same as for a class or struct. Maybe it 10480 // internally implements a pointer to member as a struct? Who knows. 10481 PointerToMemberFunction = 12, // Not a bug, see above. 10482 ClassOrStruct = 12, 10483 Union = 13, 10484 // GCC reserves 14 for arrays, but does not use it since GCC version 6 due to 10485 // decay to pointer. (Prior to version 6 it was only used in C++ mode). 10486 // GCC reserves 15 for strings, but actually uses 5 (pointer) for string 10487 // literals. 10488 }; 10489 10490 /// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way 10491 /// as GCC. 10492 static GCCTypeClass 10493 EvaluateBuiltinClassifyType(QualType T, const LangOptions &LangOpts) { 10494 assert(!T->isDependentType() && "unexpected dependent type"); 10495 10496 QualType CanTy = T.getCanonicalType(); 10497 const BuiltinType *BT = dyn_cast<BuiltinType>(CanTy); 10498 10499 switch (CanTy->getTypeClass()) { 10500 #define TYPE(ID, BASE) 10501 #define DEPENDENT_TYPE(ID, BASE) case Type::ID: 10502 #define NON_CANONICAL_TYPE(ID, BASE) case Type::ID: 10503 #define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(ID, BASE) case Type::ID: 10504 #include "clang/AST/TypeNodes.inc" 10505 case Type::Auto: 10506 case Type::DeducedTemplateSpecialization: 10507 llvm_unreachable("unexpected non-canonical or dependent type"); 10508 10509 case Type::Builtin: 10510 switch (BT->getKind()) { 10511 #define BUILTIN_TYPE(ID, SINGLETON_ID) 10512 #define SIGNED_TYPE(ID, SINGLETON_ID) \ 10513 case BuiltinType::ID: return GCCTypeClass::Integer; 10514 #define FLOATING_TYPE(ID, SINGLETON_ID) \ 10515 case BuiltinType::ID: return GCCTypeClass::RealFloat; 10516 #define PLACEHOLDER_TYPE(ID, SINGLETON_ID) \ 10517 case BuiltinType::ID: break; 10518 #include "clang/AST/BuiltinTypes.def" 10519 case BuiltinType::Void: 10520 return GCCTypeClass::Void; 10521 10522 case BuiltinType::Bool: 10523 return GCCTypeClass::Bool; 10524 10525 case BuiltinType::Char_U: 10526 case BuiltinType::UChar: 10527 case BuiltinType::WChar_U: 10528 case BuiltinType::Char8: 10529 case BuiltinType::Char16: 10530 case BuiltinType::Char32: 10531 case BuiltinType::UShort: 10532 case BuiltinType::UInt: 10533 case BuiltinType::ULong: 10534 case BuiltinType::ULongLong: 10535 case BuiltinType::UInt128: 10536 return GCCTypeClass::Integer; 10537 10538 case BuiltinType::UShortAccum: 10539 case BuiltinType::UAccum: 10540 case BuiltinType::ULongAccum: 10541 case BuiltinType::UShortFract: 10542 case BuiltinType::UFract: 10543 case BuiltinType::ULongFract: 10544 case BuiltinType::SatUShortAccum: 10545 case BuiltinType::SatUAccum: 10546 case BuiltinType::SatULongAccum: 10547 case BuiltinType::SatUShortFract: 10548 case BuiltinType::SatUFract: 10549 case BuiltinType::SatULongFract: 10550 return GCCTypeClass::None; 10551 10552 case BuiltinType::NullPtr: 10553 10554 case BuiltinType::ObjCId: 10555 case BuiltinType::ObjCClass: 10556 case BuiltinType::ObjCSel: 10557 #define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \ 10558 case BuiltinType::Id: 10559 #include "clang/Basic/OpenCLImageTypes.def" 10560 #define EXT_OPAQUE_TYPE(ExtType, Id, Ext) \ 10561 case BuiltinType::Id: 10562 #include "clang/Basic/OpenCLExtensionTypes.def" 10563 case BuiltinType::OCLSampler: 10564 case BuiltinType::OCLEvent: 10565 case BuiltinType::OCLClkEvent: 10566 case BuiltinType::OCLQueue: 10567 case BuiltinType::OCLReserveID: 10568 #define SVE_TYPE(Name, Id, SingletonId) \ 10569 case BuiltinType::Id: 10570 #include "clang/Basic/AArch64SVEACLETypes.def" 10571 return GCCTypeClass::None; 10572 10573 case BuiltinType::Dependent: 10574 llvm_unreachable("unexpected dependent type"); 10575 }; 10576 llvm_unreachable("unexpected placeholder type"); 10577 10578 case Type::Enum: 10579 return LangOpts.CPlusPlus ? GCCTypeClass::Enum : GCCTypeClass::Integer; 10580 10581 case Type::Pointer: 10582 case Type::ConstantArray: 10583 case Type::VariableArray: 10584 case Type::IncompleteArray: 10585 case Type::FunctionNoProto: 10586 case Type::FunctionProto: 10587 return GCCTypeClass::Pointer; 10588 10589 case Type::MemberPointer: 10590 return CanTy->isMemberDataPointerType() 10591 ? GCCTypeClass::PointerToDataMember 10592 : GCCTypeClass::PointerToMemberFunction; 10593 10594 case Type::Complex: 10595 return GCCTypeClass::Complex; 10596 10597 case Type::Record: 10598 return CanTy->isUnionType() ? GCCTypeClass::Union 10599 : GCCTypeClass::ClassOrStruct; 10600 10601 case Type::Atomic: 10602 // GCC classifies _Atomic T the same as T. 10603 return EvaluateBuiltinClassifyType( 10604 CanTy->castAs<AtomicType>()->getValueType(), LangOpts); 10605 10606 case Type::BlockPointer: 10607 case Type::Vector: 10608 case Type::ExtVector: 10609 case Type::ConstantMatrix: 10610 case Type::ObjCObject: 10611 case Type::ObjCInterface: 10612 case Type::ObjCObjectPointer: 10613 case Type::Pipe: 10614 case Type::ExtInt: 10615 // GCC classifies vectors as None. We follow its lead and classify all 10616 // other types that don't fit into the regular classification the same way. 10617 return GCCTypeClass::None; 10618 10619 case Type::LValueReference: 10620 case Type::RValueReference: 10621 llvm_unreachable("invalid type for expression"); 10622 } 10623 10624 llvm_unreachable("unexpected type class"); 10625 } 10626 10627 /// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way 10628 /// as GCC. 10629 static GCCTypeClass 10630 EvaluateBuiltinClassifyType(const CallExpr *E, const LangOptions &LangOpts) { 10631 // If no argument was supplied, default to None. This isn't 10632 // ideal, however it is what gcc does. 10633 if (E->getNumArgs() == 0) 10634 return GCCTypeClass::None; 10635 10636 // FIXME: Bizarrely, GCC treats a call with more than one argument as not 10637 // being an ICE, but still folds it to a constant using the type of the first 10638 // argument. 10639 return EvaluateBuiltinClassifyType(E->getArg(0)->getType(), LangOpts); 10640 } 10641 10642 /// EvaluateBuiltinConstantPForLValue - Determine the result of 10643 /// __builtin_constant_p when applied to the given pointer. 10644 /// 10645 /// A pointer is only "constant" if it is null (or a pointer cast to integer) 10646 /// or it points to the first character of a string literal. 10647 static bool EvaluateBuiltinConstantPForLValue(const APValue &LV) { 10648 APValue::LValueBase Base = LV.getLValueBase(); 10649 if (Base.isNull()) { 10650 // A null base is acceptable. 10651 return true; 10652 } else if (const Expr *E = Base.dyn_cast<const Expr *>()) { 10653 if (!isa<StringLiteral>(E)) 10654 return false; 10655 return LV.getLValueOffset().isZero(); 10656 } else if (Base.is<TypeInfoLValue>()) { 10657 // Surprisingly, GCC considers __builtin_constant_p(&typeid(int)) to 10658 // evaluate to true. 10659 return true; 10660 } else { 10661 // Any other base is not constant enough for GCC. 10662 return false; 10663 } 10664 } 10665 10666 /// EvaluateBuiltinConstantP - Evaluate __builtin_constant_p as similarly to 10667 /// GCC as we can manage. 10668 static bool EvaluateBuiltinConstantP(EvalInfo &Info, const Expr *Arg) { 10669 // This evaluation is not permitted to have side-effects, so evaluate it in 10670 // a speculative evaluation context. 10671 SpeculativeEvaluationRAII SpeculativeEval(Info); 10672 10673 // Constant-folding is always enabled for the operand of __builtin_constant_p 10674 // (even when the enclosing evaluation context otherwise requires a strict 10675 // language-specific constant expression). 10676 FoldConstant Fold(Info, true); 10677 10678 QualType ArgType = Arg->getType(); 10679 10680 // __builtin_constant_p always has one operand. The rules which gcc follows 10681 // are not precisely documented, but are as follows: 10682 // 10683 // - If the operand is of integral, floating, complex or enumeration type, 10684 // and can be folded to a known value of that type, it returns 1. 10685 // - If the operand can be folded to a pointer to the first character 10686 // of a string literal (or such a pointer cast to an integral type) 10687 // or to a null pointer or an integer cast to a pointer, it returns 1. 10688 // 10689 // Otherwise, it returns 0. 10690 // 10691 // FIXME: GCC also intends to return 1 for literals of aggregate types, but 10692 // its support for this did not work prior to GCC 9 and is not yet well 10693 // understood. 10694 if (ArgType->isIntegralOrEnumerationType() || ArgType->isFloatingType() || 10695 ArgType->isAnyComplexType() || ArgType->isPointerType() || 10696 ArgType->isNullPtrType()) { 10697 APValue V; 10698 if (!::EvaluateAsRValue(Info, Arg, V) || Info.EvalStatus.HasSideEffects) { 10699 Fold.keepDiagnostics(); 10700 return false; 10701 } 10702 10703 // For a pointer (possibly cast to integer), there are special rules. 10704 if (V.getKind() == APValue::LValue) 10705 return EvaluateBuiltinConstantPForLValue(V); 10706 10707 // Otherwise, any constant value is good enough. 10708 return V.hasValue(); 10709 } 10710 10711 // Anything else isn't considered to be sufficiently constant. 10712 return false; 10713 } 10714 10715 /// Retrieves the "underlying object type" of the given expression, 10716 /// as used by __builtin_object_size. 10717 static QualType getObjectType(APValue::LValueBase B) { 10718 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) { 10719 if (const VarDecl *VD = dyn_cast<VarDecl>(D)) 10720 return VD->getType(); 10721 } else if (const Expr *E = B.dyn_cast<const Expr*>()) { 10722 if (isa<CompoundLiteralExpr>(E)) 10723 return E->getType(); 10724 } else if (B.is<TypeInfoLValue>()) { 10725 return B.getTypeInfoType(); 10726 } else if (B.is<DynamicAllocLValue>()) { 10727 return B.getDynamicAllocType(); 10728 } 10729 10730 return QualType(); 10731 } 10732 10733 /// A more selective version of E->IgnoreParenCasts for 10734 /// tryEvaluateBuiltinObjectSize. This ignores some casts/parens that serve only 10735 /// to change the type of E. 10736 /// Ex. For E = `(short*)((char*)(&foo))`, returns `&foo` 10737 /// 10738 /// Always returns an RValue with a pointer representation. 10739 static const Expr *ignorePointerCastsAndParens(const Expr *E) { 10740 assert(E->isRValue() && E->getType()->hasPointerRepresentation()); 10741 10742 auto *NoParens = E->IgnoreParens(); 10743 auto *Cast = dyn_cast<CastExpr>(NoParens); 10744 if (Cast == nullptr) 10745 return NoParens; 10746 10747 // We only conservatively allow a few kinds of casts, because this code is 10748 // inherently a simple solution that seeks to support the common case. 10749 auto CastKind = Cast->getCastKind(); 10750 if (CastKind != CK_NoOp && CastKind != CK_BitCast && 10751 CastKind != CK_AddressSpaceConversion) 10752 return NoParens; 10753 10754 auto *SubExpr = Cast->getSubExpr(); 10755 if (!SubExpr->getType()->hasPointerRepresentation() || !SubExpr->isRValue()) 10756 return NoParens; 10757 return ignorePointerCastsAndParens(SubExpr); 10758 } 10759 10760 /// Checks to see if the given LValue's Designator is at the end of the LValue's 10761 /// record layout. e.g. 10762 /// struct { struct { int a, b; } fst, snd; } obj; 10763 /// obj.fst // no 10764 /// obj.snd // yes 10765 /// obj.fst.a // no 10766 /// obj.fst.b // no 10767 /// obj.snd.a // no 10768 /// obj.snd.b // yes 10769 /// 10770 /// Please note: this function is specialized for how __builtin_object_size 10771 /// views "objects". 10772 /// 10773 /// If this encounters an invalid RecordDecl or otherwise cannot determine the 10774 /// correct result, it will always return true. 10775 static bool isDesignatorAtObjectEnd(const ASTContext &Ctx, const LValue &LVal) { 10776 assert(!LVal.Designator.Invalid); 10777 10778 auto IsLastOrInvalidFieldDecl = [&Ctx](const FieldDecl *FD, bool &Invalid) { 10779 const RecordDecl *Parent = FD->getParent(); 10780 Invalid = Parent->isInvalidDecl(); 10781 if (Invalid || Parent->isUnion()) 10782 return true; 10783 const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(Parent); 10784 return FD->getFieldIndex() + 1 == Layout.getFieldCount(); 10785 }; 10786 10787 auto &Base = LVal.getLValueBase(); 10788 if (auto *ME = dyn_cast_or_null<MemberExpr>(Base.dyn_cast<const Expr *>())) { 10789 if (auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl())) { 10790 bool Invalid; 10791 if (!IsLastOrInvalidFieldDecl(FD, Invalid)) 10792 return Invalid; 10793 } else if (auto *IFD = dyn_cast<IndirectFieldDecl>(ME->getMemberDecl())) { 10794 for (auto *FD : IFD->chain()) { 10795 bool Invalid; 10796 if (!IsLastOrInvalidFieldDecl(cast<FieldDecl>(FD), Invalid)) 10797 return Invalid; 10798 } 10799 } 10800 } 10801 10802 unsigned I = 0; 10803 QualType BaseType = getType(Base); 10804 if (LVal.Designator.FirstEntryIsAnUnsizedArray) { 10805 // If we don't know the array bound, conservatively assume we're looking at 10806 // the final array element. 10807 ++I; 10808 if (BaseType->isIncompleteArrayType()) 10809 BaseType = Ctx.getAsArrayType(BaseType)->getElementType(); 10810 else 10811 BaseType = BaseType->castAs<PointerType>()->getPointeeType(); 10812 } 10813 10814 for (unsigned E = LVal.Designator.Entries.size(); I != E; ++I) { 10815 const auto &Entry = LVal.Designator.Entries[I]; 10816 if (BaseType->isArrayType()) { 10817 // Because __builtin_object_size treats arrays as objects, we can ignore 10818 // the index iff this is the last array in the Designator. 10819 if (I + 1 == E) 10820 return true; 10821 const auto *CAT = cast<ConstantArrayType>(Ctx.getAsArrayType(BaseType)); 10822 uint64_t Index = Entry.getAsArrayIndex(); 10823 if (Index + 1 != CAT->getSize()) 10824 return false; 10825 BaseType = CAT->getElementType(); 10826 } else if (BaseType->isAnyComplexType()) { 10827 const auto *CT = BaseType->castAs<ComplexType>(); 10828 uint64_t Index = Entry.getAsArrayIndex(); 10829 if (Index != 1) 10830 return false; 10831 BaseType = CT->getElementType(); 10832 } else if (auto *FD = getAsField(Entry)) { 10833 bool Invalid; 10834 if (!IsLastOrInvalidFieldDecl(FD, Invalid)) 10835 return Invalid; 10836 BaseType = FD->getType(); 10837 } else { 10838 assert(getAsBaseClass(Entry) && "Expecting cast to a base class"); 10839 return false; 10840 } 10841 } 10842 return true; 10843 } 10844 10845 /// Tests to see if the LValue has a user-specified designator (that isn't 10846 /// necessarily valid). Note that this always returns 'true' if the LValue has 10847 /// an unsized array as its first designator entry, because there's currently no 10848 /// way to tell if the user typed *foo or foo[0]. 10849 static bool refersToCompleteObject(const LValue &LVal) { 10850 if (LVal.Designator.Invalid) 10851 return false; 10852 10853 if (!LVal.Designator.Entries.empty()) 10854 return LVal.Designator.isMostDerivedAnUnsizedArray(); 10855 10856 if (!LVal.InvalidBase) 10857 return true; 10858 10859 // If `E` is a MemberExpr, then the first part of the designator is hiding in 10860 // the LValueBase. 10861 const auto *E = LVal.Base.dyn_cast<const Expr *>(); 10862 return !E || !isa<MemberExpr>(E); 10863 } 10864 10865 /// Attempts to detect a user writing into a piece of memory that's impossible 10866 /// to figure out the size of by just using types. 10867 static bool isUserWritingOffTheEnd(const ASTContext &Ctx, const LValue &LVal) { 10868 const SubobjectDesignator &Designator = LVal.Designator; 10869 // Notes: 10870 // - Users can only write off of the end when we have an invalid base. Invalid 10871 // bases imply we don't know where the memory came from. 10872 // - We used to be a bit more aggressive here; we'd only be conservative if 10873 // the array at the end was flexible, or if it had 0 or 1 elements. This 10874 // broke some common standard library extensions (PR30346), but was 10875 // otherwise seemingly fine. It may be useful to reintroduce this behavior 10876 // with some sort of list. OTOH, it seems that GCC is always 10877 // conservative with the last element in structs (if it's an array), so our 10878 // current behavior is more compatible than an explicit list approach would 10879 // be. 10880 return LVal.InvalidBase && 10881 Designator.Entries.size() == Designator.MostDerivedPathLength && 10882 Designator.MostDerivedIsArrayElement && 10883 isDesignatorAtObjectEnd(Ctx, LVal); 10884 } 10885 10886 /// Converts the given APInt to CharUnits, assuming the APInt is unsigned. 10887 /// Fails if the conversion would cause loss of precision. 10888 static bool convertUnsignedAPIntToCharUnits(const llvm::APInt &Int, 10889 CharUnits &Result) { 10890 auto CharUnitsMax = std::numeric_limits<CharUnits::QuantityType>::max(); 10891 if (Int.ugt(CharUnitsMax)) 10892 return false; 10893 Result = CharUnits::fromQuantity(Int.getZExtValue()); 10894 return true; 10895 } 10896 10897 /// Helper for tryEvaluateBuiltinObjectSize -- Given an LValue, this will 10898 /// determine how many bytes exist from the beginning of the object to either 10899 /// the end of the current subobject, or the end of the object itself, depending 10900 /// on what the LValue looks like + the value of Type. 10901 /// 10902 /// If this returns false, the value of Result is undefined. 10903 static bool determineEndOffset(EvalInfo &Info, SourceLocation ExprLoc, 10904 unsigned Type, const LValue &LVal, 10905 CharUnits &EndOffset) { 10906 bool DetermineForCompleteObject = refersToCompleteObject(LVal); 10907 10908 auto CheckedHandleSizeof = [&](QualType Ty, CharUnits &Result) { 10909 if (Ty.isNull() || Ty->isIncompleteType() || Ty->isFunctionType()) 10910 return false; 10911 return HandleSizeof(Info, ExprLoc, Ty, Result); 10912 }; 10913 10914 // We want to evaluate the size of the entire object. This is a valid fallback 10915 // for when Type=1 and the designator is invalid, because we're asked for an 10916 // upper-bound. 10917 if (!(Type & 1) || LVal.Designator.Invalid || DetermineForCompleteObject) { 10918 // Type=3 wants a lower bound, so we can't fall back to this. 10919 if (Type == 3 && !DetermineForCompleteObject) 10920 return false; 10921 10922 llvm::APInt APEndOffset; 10923 if (isBaseAnAllocSizeCall(LVal.getLValueBase()) && 10924 getBytesReturnedByAllocSizeCall(Info.Ctx, LVal, APEndOffset)) 10925 return convertUnsignedAPIntToCharUnits(APEndOffset, EndOffset); 10926 10927 if (LVal.InvalidBase) 10928 return false; 10929 10930 QualType BaseTy = getObjectType(LVal.getLValueBase()); 10931 return CheckedHandleSizeof(BaseTy, EndOffset); 10932 } 10933 10934 // We want to evaluate the size of a subobject. 10935 const SubobjectDesignator &Designator = LVal.Designator; 10936 10937 // The following is a moderately common idiom in C: 10938 // 10939 // struct Foo { int a; char c[1]; }; 10940 // struct Foo *F = (struct Foo *)malloc(sizeof(struct Foo) + strlen(Bar)); 10941 // strcpy(&F->c[0], Bar); 10942 // 10943 // In order to not break too much legacy code, we need to support it. 10944 if (isUserWritingOffTheEnd(Info.Ctx, LVal)) { 10945 // If we can resolve this to an alloc_size call, we can hand that back, 10946 // because we know for certain how many bytes there are to write to. 10947 llvm::APInt APEndOffset; 10948 if (isBaseAnAllocSizeCall(LVal.getLValueBase()) && 10949 getBytesReturnedByAllocSizeCall(Info.Ctx, LVal, APEndOffset)) 10950 return convertUnsignedAPIntToCharUnits(APEndOffset, EndOffset); 10951 10952 // If we cannot determine the size of the initial allocation, then we can't 10953 // given an accurate upper-bound. However, we are still able to give 10954 // conservative lower-bounds for Type=3. 10955 if (Type == 1) 10956 return false; 10957 } 10958 10959 CharUnits BytesPerElem; 10960 if (!CheckedHandleSizeof(Designator.MostDerivedType, BytesPerElem)) 10961 return false; 10962 10963 // According to the GCC documentation, we want the size of the subobject 10964 // denoted by the pointer. But that's not quite right -- what we actually 10965 // want is the size of the immediately-enclosing array, if there is one. 10966 int64_t ElemsRemaining; 10967 if (Designator.MostDerivedIsArrayElement && 10968 Designator.Entries.size() == Designator.MostDerivedPathLength) { 10969 uint64_t ArraySize = Designator.getMostDerivedArraySize(); 10970 uint64_t ArrayIndex = Designator.Entries.back().getAsArrayIndex(); 10971 ElemsRemaining = ArraySize <= ArrayIndex ? 0 : ArraySize - ArrayIndex; 10972 } else { 10973 ElemsRemaining = Designator.isOnePastTheEnd() ? 0 : 1; 10974 } 10975 10976 EndOffset = LVal.getLValueOffset() + BytesPerElem * ElemsRemaining; 10977 return true; 10978 } 10979 10980 /// Tries to evaluate the __builtin_object_size for @p E. If successful, 10981 /// returns true and stores the result in @p Size. 10982 /// 10983 /// If @p WasError is non-null, this will report whether the failure to evaluate 10984 /// is to be treated as an Error in IntExprEvaluator. 10985 static bool tryEvaluateBuiltinObjectSize(const Expr *E, unsigned Type, 10986 EvalInfo &Info, uint64_t &Size) { 10987 // Determine the denoted object. 10988 LValue LVal; 10989 { 10990 // The operand of __builtin_object_size is never evaluated for side-effects. 10991 // If there are any, but we can determine the pointed-to object anyway, then 10992 // ignore the side-effects. 10993 SpeculativeEvaluationRAII SpeculativeEval(Info); 10994 IgnoreSideEffectsRAII Fold(Info); 10995 10996 if (E->isGLValue()) { 10997 // It's possible for us to be given GLValues if we're called via 10998 // Expr::tryEvaluateObjectSize. 10999 APValue RVal; 11000 if (!EvaluateAsRValue(Info, E, RVal)) 11001 return false; 11002 LVal.setFrom(Info.Ctx, RVal); 11003 } else if (!EvaluatePointer(ignorePointerCastsAndParens(E), LVal, Info, 11004 /*InvalidBaseOK=*/true)) 11005 return false; 11006 } 11007 11008 // If we point to before the start of the object, there are no accessible 11009 // bytes. 11010 if (LVal.getLValueOffset().isNegative()) { 11011 Size = 0; 11012 return true; 11013 } 11014 11015 CharUnits EndOffset; 11016 if (!determineEndOffset(Info, E->getExprLoc(), Type, LVal, EndOffset)) 11017 return false; 11018 11019 // If we've fallen outside of the end offset, just pretend there's nothing to 11020 // write to/read from. 11021 if (EndOffset <= LVal.getLValueOffset()) 11022 Size = 0; 11023 else 11024 Size = (EndOffset - LVal.getLValueOffset()).getQuantity(); 11025 return true; 11026 } 11027 11028 bool IntExprEvaluator::VisitCallExpr(const CallExpr *E) { 11029 if (unsigned BuiltinOp = E->getBuiltinCallee()) 11030 return VisitBuiltinCallExpr(E, BuiltinOp); 11031 11032 return ExprEvaluatorBaseTy::VisitCallExpr(E); 11033 } 11034 11035 static bool getBuiltinAlignArguments(const CallExpr *E, EvalInfo &Info, 11036 APValue &Val, APSInt &Alignment) { 11037 QualType SrcTy = E->getArg(0)->getType(); 11038 if (!getAlignmentArgument(E->getArg(1), SrcTy, Info, Alignment)) 11039 return false; 11040 // Even though we are evaluating integer expressions we could get a pointer 11041 // argument for the __builtin_is_aligned() case. 11042 if (SrcTy->isPointerType()) { 11043 LValue Ptr; 11044 if (!EvaluatePointer(E->getArg(0), Ptr, Info)) 11045 return false; 11046 Ptr.moveInto(Val); 11047 } else if (!SrcTy->isIntegralOrEnumerationType()) { 11048 Info.FFDiag(E->getArg(0)); 11049 return false; 11050 } else { 11051 APSInt SrcInt; 11052 if (!EvaluateInteger(E->getArg(0), SrcInt, Info)) 11053 return false; 11054 assert(SrcInt.getBitWidth() >= Alignment.getBitWidth() && 11055 "Bit widths must be the same"); 11056 Val = APValue(SrcInt); 11057 } 11058 assert(Val.hasValue()); 11059 return true; 11060 } 11061 11062 bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E, 11063 unsigned BuiltinOp) { 11064 switch (BuiltinOp) { 11065 default: 11066 return ExprEvaluatorBaseTy::VisitCallExpr(E); 11067 11068 case Builtin::BI__builtin_dynamic_object_size: 11069 case Builtin::BI__builtin_object_size: { 11070 // The type was checked when we built the expression. 11071 unsigned Type = 11072 E->getArg(1)->EvaluateKnownConstInt(Info.Ctx).getZExtValue(); 11073 assert(Type <= 3 && "unexpected type"); 11074 11075 uint64_t Size; 11076 if (tryEvaluateBuiltinObjectSize(E->getArg(0), Type, Info, Size)) 11077 return Success(Size, E); 11078 11079 if (E->getArg(0)->HasSideEffects(Info.Ctx)) 11080 return Success((Type & 2) ? 0 : -1, E); 11081 11082 // Expression had no side effects, but we couldn't statically determine the 11083 // size of the referenced object. 11084 switch (Info.EvalMode) { 11085 case EvalInfo::EM_ConstantExpression: 11086 case EvalInfo::EM_ConstantFold: 11087 case EvalInfo::EM_IgnoreSideEffects: 11088 // Leave it to IR generation. 11089 return Error(E); 11090 case EvalInfo::EM_ConstantExpressionUnevaluated: 11091 // Reduce it to a constant now. 11092 return Success((Type & 2) ? 0 : -1, E); 11093 } 11094 11095 llvm_unreachable("unexpected EvalMode"); 11096 } 11097 11098 case Builtin::BI__builtin_os_log_format_buffer_size: { 11099 analyze_os_log::OSLogBufferLayout Layout; 11100 analyze_os_log::computeOSLogBufferLayout(Info.Ctx, E, Layout); 11101 return Success(Layout.size().getQuantity(), E); 11102 } 11103 11104 case Builtin::BI__builtin_is_aligned: { 11105 APValue Src; 11106 APSInt Alignment; 11107 if (!getBuiltinAlignArguments(E, Info, Src, Alignment)) 11108 return false; 11109 if (Src.isLValue()) { 11110 // If we evaluated a pointer, check the minimum known alignment. 11111 LValue Ptr; 11112 Ptr.setFrom(Info.Ctx, Src); 11113 CharUnits BaseAlignment = getBaseAlignment(Info, Ptr); 11114 CharUnits PtrAlign = BaseAlignment.alignmentAtOffset(Ptr.Offset); 11115 // We can return true if the known alignment at the computed offset is 11116 // greater than the requested alignment. 11117 assert(PtrAlign.isPowerOfTwo()); 11118 assert(Alignment.isPowerOf2()); 11119 if (PtrAlign.getQuantity() >= Alignment) 11120 return Success(1, E); 11121 // If the alignment is not known to be sufficient, some cases could still 11122 // be aligned at run time. However, if the requested alignment is less or 11123 // equal to the base alignment and the offset is not aligned, we know that 11124 // the run-time value can never be aligned. 11125 if (BaseAlignment.getQuantity() >= Alignment && 11126 PtrAlign.getQuantity() < Alignment) 11127 return Success(0, E); 11128 // Otherwise we can't infer whether the value is sufficiently aligned. 11129 // TODO: __builtin_is_aligned(__builtin_align_{down,up{(expr, N), N) 11130 // in cases where we can't fully evaluate the pointer. 11131 Info.FFDiag(E->getArg(0), diag::note_constexpr_alignment_compute) 11132 << Alignment; 11133 return false; 11134 } 11135 assert(Src.isInt()); 11136 return Success((Src.getInt() & (Alignment - 1)) == 0 ? 1 : 0, E); 11137 } 11138 case Builtin::BI__builtin_align_up: { 11139 APValue Src; 11140 APSInt Alignment; 11141 if (!getBuiltinAlignArguments(E, Info, Src, Alignment)) 11142 return false; 11143 if (!Src.isInt()) 11144 return Error(E); 11145 APSInt AlignedVal = 11146 APSInt((Src.getInt() + (Alignment - 1)) & ~(Alignment - 1), 11147 Src.getInt().isUnsigned()); 11148 assert(AlignedVal.getBitWidth() == Src.getInt().getBitWidth()); 11149 return Success(AlignedVal, E); 11150 } 11151 case Builtin::BI__builtin_align_down: { 11152 APValue Src; 11153 APSInt Alignment; 11154 if (!getBuiltinAlignArguments(E, Info, Src, Alignment)) 11155 return false; 11156 if (!Src.isInt()) 11157 return Error(E); 11158 APSInt AlignedVal = 11159 APSInt(Src.getInt() & ~(Alignment - 1), Src.getInt().isUnsigned()); 11160 assert(AlignedVal.getBitWidth() == Src.getInt().getBitWidth()); 11161 return Success(AlignedVal, E); 11162 } 11163 11164 case Builtin::BI__builtin_bswap16: 11165 case Builtin::BI__builtin_bswap32: 11166 case Builtin::BI__builtin_bswap64: { 11167 APSInt Val; 11168 if (!EvaluateInteger(E->getArg(0), Val, Info)) 11169 return false; 11170 11171 return Success(Val.byteSwap(), E); 11172 } 11173 11174 case Builtin::BI__builtin_classify_type: 11175 return Success((int)EvaluateBuiltinClassifyType(E, Info.getLangOpts()), E); 11176 11177 case Builtin::BI__builtin_clrsb: 11178 case Builtin::BI__builtin_clrsbl: 11179 case Builtin::BI__builtin_clrsbll: { 11180 APSInt Val; 11181 if (!EvaluateInteger(E->getArg(0), Val, Info)) 11182 return false; 11183 11184 return Success(Val.getBitWidth() - Val.getMinSignedBits(), E); 11185 } 11186 11187 case Builtin::BI__builtin_clz: 11188 case Builtin::BI__builtin_clzl: 11189 case Builtin::BI__builtin_clzll: 11190 case Builtin::BI__builtin_clzs: { 11191 APSInt Val; 11192 if (!EvaluateInteger(E->getArg(0), Val, Info)) 11193 return false; 11194 if (!Val) 11195 return Error(E); 11196 11197 return Success(Val.countLeadingZeros(), E); 11198 } 11199 11200 case Builtin::BI__builtin_constant_p: { 11201 const Expr *Arg = E->getArg(0); 11202 if (EvaluateBuiltinConstantP(Info, Arg)) 11203 return Success(true, E); 11204 if (Info.InConstantContext || Arg->HasSideEffects(Info.Ctx)) { 11205 // Outside a constant context, eagerly evaluate to false in the presence 11206 // of side-effects in order to avoid -Wunsequenced false-positives in 11207 // a branch on __builtin_constant_p(expr). 11208 return Success(false, E); 11209 } 11210 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr); 11211 return false; 11212 } 11213 11214 case Builtin::BI__builtin_is_constant_evaluated: { 11215 const auto *Callee = Info.CurrentCall->getCallee(); 11216 if (Info.InConstantContext && !Info.CheckingPotentialConstantExpression && 11217 (Info.CallStackDepth == 1 || 11218 (Info.CallStackDepth == 2 && Callee->isInStdNamespace() && 11219 Callee->getIdentifier() && 11220 Callee->getIdentifier()->isStr("is_constant_evaluated")))) { 11221 // FIXME: Find a better way to avoid duplicated diagnostics. 11222 if (Info.EvalStatus.Diag) 11223 Info.report((Info.CallStackDepth == 1) ? E->getExprLoc() 11224 : Info.CurrentCall->CallLoc, 11225 diag::warn_is_constant_evaluated_always_true_constexpr) 11226 << (Info.CallStackDepth == 1 ? "__builtin_is_constant_evaluated" 11227 : "std::is_constant_evaluated"); 11228 } 11229 11230 return Success(Info.InConstantContext, E); 11231 } 11232 11233 case Builtin::BI__builtin_ctz: 11234 case Builtin::BI__builtin_ctzl: 11235 case Builtin::BI__builtin_ctzll: 11236 case Builtin::BI__builtin_ctzs: { 11237 APSInt Val; 11238 if (!EvaluateInteger(E->getArg(0), Val, Info)) 11239 return false; 11240 if (!Val) 11241 return Error(E); 11242 11243 return Success(Val.countTrailingZeros(), E); 11244 } 11245 11246 case Builtin::BI__builtin_eh_return_data_regno: { 11247 int Operand = E->getArg(0)->EvaluateKnownConstInt(Info.Ctx).getZExtValue(); 11248 Operand = Info.Ctx.getTargetInfo().getEHDataRegisterNumber(Operand); 11249 return Success(Operand, E); 11250 } 11251 11252 case Builtin::BI__builtin_expect: 11253 case Builtin::BI__builtin_expect_with_probability: 11254 return Visit(E->getArg(0)); 11255 11256 case Builtin::BI__builtin_ffs: 11257 case Builtin::BI__builtin_ffsl: 11258 case Builtin::BI__builtin_ffsll: { 11259 APSInt Val; 11260 if (!EvaluateInteger(E->getArg(0), Val, Info)) 11261 return false; 11262 11263 unsigned N = Val.countTrailingZeros(); 11264 return Success(N == Val.getBitWidth() ? 0 : N + 1, E); 11265 } 11266 11267 case Builtin::BI__builtin_fpclassify: { 11268 APFloat Val(0.0); 11269 if (!EvaluateFloat(E->getArg(5), Val, Info)) 11270 return false; 11271 unsigned Arg; 11272 switch (Val.getCategory()) { 11273 case APFloat::fcNaN: Arg = 0; break; 11274 case APFloat::fcInfinity: Arg = 1; break; 11275 case APFloat::fcNormal: Arg = Val.isDenormal() ? 3 : 2; break; 11276 case APFloat::fcZero: Arg = 4; break; 11277 } 11278 return Visit(E->getArg(Arg)); 11279 } 11280 11281 case Builtin::BI__builtin_isinf_sign: { 11282 APFloat Val(0.0); 11283 return EvaluateFloat(E->getArg(0), Val, Info) && 11284 Success(Val.isInfinity() ? (Val.isNegative() ? -1 : 1) : 0, E); 11285 } 11286 11287 case Builtin::BI__builtin_isinf: { 11288 APFloat Val(0.0); 11289 return EvaluateFloat(E->getArg(0), Val, Info) && 11290 Success(Val.isInfinity() ? 1 : 0, E); 11291 } 11292 11293 case Builtin::BI__builtin_isfinite: { 11294 APFloat Val(0.0); 11295 return EvaluateFloat(E->getArg(0), Val, Info) && 11296 Success(Val.isFinite() ? 1 : 0, E); 11297 } 11298 11299 case Builtin::BI__builtin_isnan: { 11300 APFloat Val(0.0); 11301 return EvaluateFloat(E->getArg(0), Val, Info) && 11302 Success(Val.isNaN() ? 1 : 0, E); 11303 } 11304 11305 case Builtin::BI__builtin_isnormal: { 11306 APFloat Val(0.0); 11307 return EvaluateFloat(E->getArg(0), Val, Info) && 11308 Success(Val.isNormal() ? 1 : 0, E); 11309 } 11310 11311 case Builtin::BI__builtin_parity: 11312 case Builtin::BI__builtin_parityl: 11313 case Builtin::BI__builtin_parityll: { 11314 APSInt Val; 11315 if (!EvaluateInteger(E->getArg(0), Val, Info)) 11316 return false; 11317 11318 return Success(Val.countPopulation() % 2, E); 11319 } 11320 11321 case Builtin::BI__builtin_popcount: 11322 case Builtin::BI__builtin_popcountl: 11323 case Builtin::BI__builtin_popcountll: { 11324 APSInt Val; 11325 if (!EvaluateInteger(E->getArg(0), Val, Info)) 11326 return false; 11327 11328 return Success(Val.countPopulation(), E); 11329 } 11330 11331 case Builtin::BIstrlen: 11332 case Builtin::BIwcslen: 11333 // A call to strlen is not a constant expression. 11334 if (Info.getLangOpts().CPlusPlus11) 11335 Info.CCEDiag(E, diag::note_constexpr_invalid_function) 11336 << /*isConstexpr*/0 << /*isConstructor*/0 11337 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'"); 11338 else 11339 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr); 11340 LLVM_FALLTHROUGH; 11341 case Builtin::BI__builtin_strlen: 11342 case Builtin::BI__builtin_wcslen: { 11343 // As an extension, we support __builtin_strlen() as a constant expression, 11344 // and support folding strlen() to a constant. 11345 LValue String; 11346 if (!EvaluatePointer(E->getArg(0), String, Info)) 11347 return false; 11348 11349 QualType CharTy = E->getArg(0)->getType()->getPointeeType(); 11350 11351 // Fast path: if it's a string literal, search the string value. 11352 if (const StringLiteral *S = dyn_cast_or_null<StringLiteral>( 11353 String.getLValueBase().dyn_cast<const Expr *>())) { 11354 // The string literal may have embedded null characters. Find the first 11355 // one and truncate there. 11356 StringRef Str = S->getBytes(); 11357 int64_t Off = String.Offset.getQuantity(); 11358 if (Off >= 0 && (uint64_t)Off <= (uint64_t)Str.size() && 11359 S->getCharByteWidth() == 1 && 11360 // FIXME: Add fast-path for wchar_t too. 11361 Info.Ctx.hasSameUnqualifiedType(CharTy, Info.Ctx.CharTy)) { 11362 Str = Str.substr(Off); 11363 11364 StringRef::size_type Pos = Str.find(0); 11365 if (Pos != StringRef::npos) 11366 Str = Str.substr(0, Pos); 11367 11368 return Success(Str.size(), E); 11369 } 11370 11371 // Fall through to slow path to issue appropriate diagnostic. 11372 } 11373 11374 // Slow path: scan the bytes of the string looking for the terminating 0. 11375 for (uint64_t Strlen = 0; /**/; ++Strlen) { 11376 APValue Char; 11377 if (!handleLValueToRValueConversion(Info, E, CharTy, String, Char) || 11378 !Char.isInt()) 11379 return false; 11380 if (!Char.getInt()) 11381 return Success(Strlen, E); 11382 if (!HandleLValueArrayAdjustment(Info, E, String, CharTy, 1)) 11383 return false; 11384 } 11385 } 11386 11387 case Builtin::BIstrcmp: 11388 case Builtin::BIwcscmp: 11389 case Builtin::BIstrncmp: 11390 case Builtin::BIwcsncmp: 11391 case Builtin::BImemcmp: 11392 case Builtin::BIbcmp: 11393 case Builtin::BIwmemcmp: 11394 // A call to strlen is not a constant expression. 11395 if (Info.getLangOpts().CPlusPlus11) 11396 Info.CCEDiag(E, diag::note_constexpr_invalid_function) 11397 << /*isConstexpr*/0 << /*isConstructor*/0 11398 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'"); 11399 else 11400 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr); 11401 LLVM_FALLTHROUGH; 11402 case Builtin::BI__builtin_strcmp: 11403 case Builtin::BI__builtin_wcscmp: 11404 case Builtin::BI__builtin_strncmp: 11405 case Builtin::BI__builtin_wcsncmp: 11406 case Builtin::BI__builtin_memcmp: 11407 case Builtin::BI__builtin_bcmp: 11408 case Builtin::BI__builtin_wmemcmp: { 11409 LValue String1, String2; 11410 if (!EvaluatePointer(E->getArg(0), String1, Info) || 11411 !EvaluatePointer(E->getArg(1), String2, Info)) 11412 return false; 11413 11414 uint64_t MaxLength = uint64_t(-1); 11415 if (BuiltinOp != Builtin::BIstrcmp && 11416 BuiltinOp != Builtin::BIwcscmp && 11417 BuiltinOp != Builtin::BI__builtin_strcmp && 11418 BuiltinOp != Builtin::BI__builtin_wcscmp) { 11419 APSInt N; 11420 if (!EvaluateInteger(E->getArg(2), N, Info)) 11421 return false; 11422 MaxLength = N.getExtValue(); 11423 } 11424 11425 // Empty substrings compare equal by definition. 11426 if (MaxLength == 0u) 11427 return Success(0, E); 11428 11429 if (!String1.checkNullPointerForFoldAccess(Info, E, AK_Read) || 11430 !String2.checkNullPointerForFoldAccess(Info, E, AK_Read) || 11431 String1.Designator.Invalid || String2.Designator.Invalid) 11432 return false; 11433 11434 QualType CharTy1 = String1.Designator.getType(Info.Ctx); 11435 QualType CharTy2 = String2.Designator.getType(Info.Ctx); 11436 11437 bool IsRawByte = BuiltinOp == Builtin::BImemcmp || 11438 BuiltinOp == Builtin::BIbcmp || 11439 BuiltinOp == Builtin::BI__builtin_memcmp || 11440 BuiltinOp == Builtin::BI__builtin_bcmp; 11441 11442 assert(IsRawByte || 11443 (Info.Ctx.hasSameUnqualifiedType( 11444 CharTy1, E->getArg(0)->getType()->getPointeeType()) && 11445 Info.Ctx.hasSameUnqualifiedType(CharTy1, CharTy2))); 11446 11447 // For memcmp, allow comparing any arrays of '[[un]signed] char' or 11448 // 'char8_t', but no other types. 11449 if (IsRawByte && 11450 !(isOneByteCharacterType(CharTy1) && isOneByteCharacterType(CharTy2))) { 11451 // FIXME: Consider using our bit_cast implementation to support this. 11452 Info.FFDiag(E, diag::note_constexpr_memcmp_unsupported) 11453 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'") 11454 << CharTy1 << CharTy2; 11455 return false; 11456 } 11457 11458 const auto &ReadCurElems = [&](APValue &Char1, APValue &Char2) { 11459 return handleLValueToRValueConversion(Info, E, CharTy1, String1, Char1) && 11460 handleLValueToRValueConversion(Info, E, CharTy2, String2, Char2) && 11461 Char1.isInt() && Char2.isInt(); 11462 }; 11463 const auto &AdvanceElems = [&] { 11464 return HandleLValueArrayAdjustment(Info, E, String1, CharTy1, 1) && 11465 HandleLValueArrayAdjustment(Info, E, String2, CharTy2, 1); 11466 }; 11467 11468 bool StopAtNull = 11469 (BuiltinOp != Builtin::BImemcmp && BuiltinOp != Builtin::BIbcmp && 11470 BuiltinOp != Builtin::BIwmemcmp && 11471 BuiltinOp != Builtin::BI__builtin_memcmp && 11472 BuiltinOp != Builtin::BI__builtin_bcmp && 11473 BuiltinOp != Builtin::BI__builtin_wmemcmp); 11474 bool IsWide = BuiltinOp == Builtin::BIwcscmp || 11475 BuiltinOp == Builtin::BIwcsncmp || 11476 BuiltinOp == Builtin::BIwmemcmp || 11477 BuiltinOp == Builtin::BI__builtin_wcscmp || 11478 BuiltinOp == Builtin::BI__builtin_wcsncmp || 11479 BuiltinOp == Builtin::BI__builtin_wmemcmp; 11480 11481 for (; MaxLength; --MaxLength) { 11482 APValue Char1, Char2; 11483 if (!ReadCurElems(Char1, Char2)) 11484 return false; 11485 if (Char1.getInt().ne(Char2.getInt())) { 11486 if (IsWide) // wmemcmp compares with wchar_t signedness. 11487 return Success(Char1.getInt() < Char2.getInt() ? -1 : 1, E); 11488 // memcmp always compares unsigned chars. 11489 return Success(Char1.getInt().ult(Char2.getInt()) ? -1 : 1, E); 11490 } 11491 if (StopAtNull && !Char1.getInt()) 11492 return Success(0, E); 11493 assert(!(StopAtNull && !Char2.getInt())); 11494 if (!AdvanceElems()) 11495 return false; 11496 } 11497 // We hit the strncmp / memcmp limit. 11498 return Success(0, E); 11499 } 11500 11501 case Builtin::BI__atomic_always_lock_free: 11502 case Builtin::BI__atomic_is_lock_free: 11503 case Builtin::BI__c11_atomic_is_lock_free: { 11504 APSInt SizeVal; 11505 if (!EvaluateInteger(E->getArg(0), SizeVal, Info)) 11506 return false; 11507 11508 // For __atomic_is_lock_free(sizeof(_Atomic(T))), if the size is a power 11509 // of two less than the maximum inline atomic width, we know it is 11510 // lock-free. If the size isn't a power of two, or greater than the 11511 // maximum alignment where we promote atomics, we know it is not lock-free 11512 // (at least not in the sense of atomic_is_lock_free). Otherwise, 11513 // the answer can only be determined at runtime; for example, 16-byte 11514 // atomics have lock-free implementations on some, but not all, 11515 // x86-64 processors. 11516 11517 // Check power-of-two. 11518 CharUnits Size = CharUnits::fromQuantity(SizeVal.getZExtValue()); 11519 if (Size.isPowerOfTwo()) { 11520 // Check against inlining width. 11521 unsigned InlineWidthBits = 11522 Info.Ctx.getTargetInfo().getMaxAtomicInlineWidth(); 11523 if (Size <= Info.Ctx.toCharUnitsFromBits(InlineWidthBits)) { 11524 if (BuiltinOp == Builtin::BI__c11_atomic_is_lock_free || 11525 Size == CharUnits::One() || 11526 E->getArg(1)->isNullPointerConstant(Info.Ctx, 11527 Expr::NPC_NeverValueDependent)) 11528 // OK, we will inline appropriately-aligned operations of this size, 11529 // and _Atomic(T) is appropriately-aligned. 11530 return Success(1, E); 11531 11532 QualType PointeeType = E->getArg(1)->IgnoreImpCasts()->getType()-> 11533 castAs<PointerType>()->getPointeeType(); 11534 if (!PointeeType->isIncompleteType() && 11535 Info.Ctx.getTypeAlignInChars(PointeeType) >= Size) { 11536 // OK, we will inline operations on this object. 11537 return Success(1, E); 11538 } 11539 } 11540 } 11541 11542 // Avoid emiting call for runtime decision on PowerPC 32-bit 11543 // The lock free possibilities on this platform are covered by the lines 11544 // above and we know in advance other cases require lock 11545 if (Info.Ctx.getTargetInfo().getTriple().getArch() == llvm::Triple::ppc) { 11546 return Success(0, E); 11547 } 11548 11549 return BuiltinOp == Builtin::BI__atomic_always_lock_free ? 11550 Success(0, E) : Error(E); 11551 } 11552 case Builtin::BIomp_is_initial_device: 11553 // We can decide statically which value the runtime would return if called. 11554 return Success(Info.getLangOpts().OpenMPIsDevice ? 0 : 1, E); 11555 case Builtin::BI__builtin_add_overflow: 11556 case Builtin::BI__builtin_sub_overflow: 11557 case Builtin::BI__builtin_mul_overflow: 11558 case Builtin::BI__builtin_sadd_overflow: 11559 case Builtin::BI__builtin_uadd_overflow: 11560 case Builtin::BI__builtin_uaddl_overflow: 11561 case Builtin::BI__builtin_uaddll_overflow: 11562 case Builtin::BI__builtin_usub_overflow: 11563 case Builtin::BI__builtin_usubl_overflow: 11564 case Builtin::BI__builtin_usubll_overflow: 11565 case Builtin::BI__builtin_umul_overflow: 11566 case Builtin::BI__builtin_umull_overflow: 11567 case Builtin::BI__builtin_umulll_overflow: 11568 case Builtin::BI__builtin_saddl_overflow: 11569 case Builtin::BI__builtin_saddll_overflow: 11570 case Builtin::BI__builtin_ssub_overflow: 11571 case Builtin::BI__builtin_ssubl_overflow: 11572 case Builtin::BI__builtin_ssubll_overflow: 11573 case Builtin::BI__builtin_smul_overflow: 11574 case Builtin::BI__builtin_smull_overflow: 11575 case Builtin::BI__builtin_smulll_overflow: { 11576 LValue ResultLValue; 11577 APSInt LHS, RHS; 11578 11579 QualType ResultType = E->getArg(2)->getType()->getPointeeType(); 11580 if (!EvaluateInteger(E->getArg(0), LHS, Info) || 11581 !EvaluateInteger(E->getArg(1), RHS, Info) || 11582 !EvaluatePointer(E->getArg(2), ResultLValue, Info)) 11583 return false; 11584 11585 APSInt Result; 11586 bool DidOverflow = false; 11587 11588 // If the types don't have to match, enlarge all 3 to the largest of them. 11589 if (BuiltinOp == Builtin::BI__builtin_add_overflow || 11590 BuiltinOp == Builtin::BI__builtin_sub_overflow || 11591 BuiltinOp == Builtin::BI__builtin_mul_overflow) { 11592 bool IsSigned = LHS.isSigned() || RHS.isSigned() || 11593 ResultType->isSignedIntegerOrEnumerationType(); 11594 bool AllSigned = LHS.isSigned() && RHS.isSigned() && 11595 ResultType->isSignedIntegerOrEnumerationType(); 11596 uint64_t LHSSize = LHS.getBitWidth(); 11597 uint64_t RHSSize = RHS.getBitWidth(); 11598 uint64_t ResultSize = Info.Ctx.getTypeSize(ResultType); 11599 uint64_t MaxBits = std::max(std::max(LHSSize, RHSSize), ResultSize); 11600 11601 // Add an additional bit if the signedness isn't uniformly agreed to. We 11602 // could do this ONLY if there is a signed and an unsigned that both have 11603 // MaxBits, but the code to check that is pretty nasty. The issue will be 11604 // caught in the shrink-to-result later anyway. 11605 if (IsSigned && !AllSigned) 11606 ++MaxBits; 11607 11608 LHS = APSInt(LHS.extOrTrunc(MaxBits), !IsSigned); 11609 RHS = APSInt(RHS.extOrTrunc(MaxBits), !IsSigned); 11610 Result = APSInt(MaxBits, !IsSigned); 11611 } 11612 11613 // Find largest int. 11614 switch (BuiltinOp) { 11615 default: 11616 llvm_unreachable("Invalid value for BuiltinOp"); 11617 case Builtin::BI__builtin_add_overflow: 11618 case Builtin::BI__builtin_sadd_overflow: 11619 case Builtin::BI__builtin_saddl_overflow: 11620 case Builtin::BI__builtin_saddll_overflow: 11621 case Builtin::BI__builtin_uadd_overflow: 11622 case Builtin::BI__builtin_uaddl_overflow: 11623 case Builtin::BI__builtin_uaddll_overflow: 11624 Result = LHS.isSigned() ? LHS.sadd_ov(RHS, DidOverflow) 11625 : LHS.uadd_ov(RHS, DidOverflow); 11626 break; 11627 case Builtin::BI__builtin_sub_overflow: 11628 case Builtin::BI__builtin_ssub_overflow: 11629 case Builtin::BI__builtin_ssubl_overflow: 11630 case Builtin::BI__builtin_ssubll_overflow: 11631 case Builtin::BI__builtin_usub_overflow: 11632 case Builtin::BI__builtin_usubl_overflow: 11633 case Builtin::BI__builtin_usubll_overflow: 11634 Result = LHS.isSigned() ? LHS.ssub_ov(RHS, DidOverflow) 11635 : LHS.usub_ov(RHS, DidOverflow); 11636 break; 11637 case Builtin::BI__builtin_mul_overflow: 11638 case Builtin::BI__builtin_smul_overflow: 11639 case Builtin::BI__builtin_smull_overflow: 11640 case Builtin::BI__builtin_smulll_overflow: 11641 case Builtin::BI__builtin_umul_overflow: 11642 case Builtin::BI__builtin_umull_overflow: 11643 case Builtin::BI__builtin_umulll_overflow: 11644 Result = LHS.isSigned() ? LHS.smul_ov(RHS, DidOverflow) 11645 : LHS.umul_ov(RHS, DidOverflow); 11646 break; 11647 } 11648 11649 // In the case where multiple sizes are allowed, truncate and see if 11650 // the values are the same. 11651 if (BuiltinOp == Builtin::BI__builtin_add_overflow || 11652 BuiltinOp == Builtin::BI__builtin_sub_overflow || 11653 BuiltinOp == Builtin::BI__builtin_mul_overflow) { 11654 // APSInt doesn't have a TruncOrSelf, so we use extOrTrunc instead, 11655 // since it will give us the behavior of a TruncOrSelf in the case where 11656 // its parameter <= its size. We previously set Result to be at least the 11657 // type-size of the result, so getTypeSize(ResultType) <= Result.BitWidth 11658 // will work exactly like TruncOrSelf. 11659 APSInt Temp = Result.extOrTrunc(Info.Ctx.getTypeSize(ResultType)); 11660 Temp.setIsSigned(ResultType->isSignedIntegerOrEnumerationType()); 11661 11662 if (!APSInt::isSameValue(Temp, Result)) 11663 DidOverflow = true; 11664 Result = Temp; 11665 } 11666 11667 APValue APV{Result}; 11668 if (!handleAssignment(Info, E, ResultLValue, ResultType, APV)) 11669 return false; 11670 return Success(DidOverflow, E); 11671 } 11672 } 11673 } 11674 11675 /// Determine whether this is a pointer past the end of the complete 11676 /// object referred to by the lvalue. 11677 static bool isOnePastTheEndOfCompleteObject(const ASTContext &Ctx, 11678 const LValue &LV) { 11679 // A null pointer can be viewed as being "past the end" but we don't 11680 // choose to look at it that way here. 11681 if (!LV.getLValueBase()) 11682 return false; 11683 11684 // If the designator is valid and refers to a subobject, we're not pointing 11685 // past the end. 11686 if (!LV.getLValueDesignator().Invalid && 11687 !LV.getLValueDesignator().isOnePastTheEnd()) 11688 return false; 11689 11690 // A pointer to an incomplete type might be past-the-end if the type's size is 11691 // zero. We cannot tell because the type is incomplete. 11692 QualType Ty = getType(LV.getLValueBase()); 11693 if (Ty->isIncompleteType()) 11694 return true; 11695 11696 // We're a past-the-end pointer if we point to the byte after the object, 11697 // no matter what our type or path is. 11698 auto Size = Ctx.getTypeSizeInChars(Ty); 11699 return LV.getLValueOffset() == Size; 11700 } 11701 11702 namespace { 11703 11704 /// Data recursive integer evaluator of certain binary operators. 11705 /// 11706 /// We use a data recursive algorithm for binary operators so that we are able 11707 /// to handle extreme cases of chained binary operators without causing stack 11708 /// overflow. 11709 class DataRecursiveIntBinOpEvaluator { 11710 struct EvalResult { 11711 APValue Val; 11712 bool Failed; 11713 11714 EvalResult() : Failed(false) { } 11715 11716 void swap(EvalResult &RHS) { 11717 Val.swap(RHS.Val); 11718 Failed = RHS.Failed; 11719 RHS.Failed = false; 11720 } 11721 }; 11722 11723 struct Job { 11724 const Expr *E; 11725 EvalResult LHSResult; // meaningful only for binary operator expression. 11726 enum { AnyExprKind, BinOpKind, BinOpVisitedLHSKind } Kind; 11727 11728 Job() = default; 11729 Job(Job &&) = default; 11730 11731 void startSpeculativeEval(EvalInfo &Info) { 11732 SpecEvalRAII = SpeculativeEvaluationRAII(Info); 11733 } 11734 11735 private: 11736 SpeculativeEvaluationRAII SpecEvalRAII; 11737 }; 11738 11739 SmallVector<Job, 16> Queue; 11740 11741 IntExprEvaluator &IntEval; 11742 EvalInfo &Info; 11743 APValue &FinalResult; 11744 11745 public: 11746 DataRecursiveIntBinOpEvaluator(IntExprEvaluator &IntEval, APValue &Result) 11747 : IntEval(IntEval), Info(IntEval.getEvalInfo()), FinalResult(Result) { } 11748 11749 /// True if \param E is a binary operator that we are going to handle 11750 /// data recursively. 11751 /// We handle binary operators that are comma, logical, or that have operands 11752 /// with integral or enumeration type. 11753 static bool shouldEnqueue(const BinaryOperator *E) { 11754 return E->getOpcode() == BO_Comma || E->isLogicalOp() || 11755 (E->isRValue() && E->getType()->isIntegralOrEnumerationType() && 11756 E->getLHS()->getType()->isIntegralOrEnumerationType() && 11757 E->getRHS()->getType()->isIntegralOrEnumerationType()); 11758 } 11759 11760 bool Traverse(const BinaryOperator *E) { 11761 enqueue(E); 11762 EvalResult PrevResult; 11763 while (!Queue.empty()) 11764 process(PrevResult); 11765 11766 if (PrevResult.Failed) return false; 11767 11768 FinalResult.swap(PrevResult.Val); 11769 return true; 11770 } 11771 11772 private: 11773 bool Success(uint64_t Value, const Expr *E, APValue &Result) { 11774 return IntEval.Success(Value, E, Result); 11775 } 11776 bool Success(const APSInt &Value, const Expr *E, APValue &Result) { 11777 return IntEval.Success(Value, E, Result); 11778 } 11779 bool Error(const Expr *E) { 11780 return IntEval.Error(E); 11781 } 11782 bool Error(const Expr *E, diag::kind D) { 11783 return IntEval.Error(E, D); 11784 } 11785 11786 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) { 11787 return Info.CCEDiag(E, D); 11788 } 11789 11790 // Returns true if visiting the RHS is necessary, false otherwise. 11791 bool VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E, 11792 bool &SuppressRHSDiags); 11793 11794 bool VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult, 11795 const BinaryOperator *E, APValue &Result); 11796 11797 void EvaluateExpr(const Expr *E, EvalResult &Result) { 11798 Result.Failed = !Evaluate(Result.Val, Info, E); 11799 if (Result.Failed) 11800 Result.Val = APValue(); 11801 } 11802 11803 void process(EvalResult &Result); 11804 11805 void enqueue(const Expr *E) { 11806 E = E->IgnoreParens(); 11807 Queue.resize(Queue.size()+1); 11808 Queue.back().E = E; 11809 Queue.back().Kind = Job::AnyExprKind; 11810 } 11811 }; 11812 11813 } 11814 11815 bool DataRecursiveIntBinOpEvaluator:: 11816 VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E, 11817 bool &SuppressRHSDiags) { 11818 if (E->getOpcode() == BO_Comma) { 11819 // Ignore LHS but note if we could not evaluate it. 11820 if (LHSResult.Failed) 11821 return Info.noteSideEffect(); 11822 return true; 11823 } 11824 11825 if (E->isLogicalOp()) { 11826 bool LHSAsBool; 11827 if (!LHSResult.Failed && HandleConversionToBool(LHSResult.Val, LHSAsBool)) { 11828 // We were able to evaluate the LHS, see if we can get away with not 11829 // evaluating the RHS: 0 && X -> 0, 1 || X -> 1 11830 if (LHSAsBool == (E->getOpcode() == BO_LOr)) { 11831 Success(LHSAsBool, E, LHSResult.Val); 11832 return false; // Ignore RHS 11833 } 11834 } else { 11835 LHSResult.Failed = true; 11836 11837 // Since we weren't able to evaluate the left hand side, it 11838 // might have had side effects. 11839 if (!Info.noteSideEffect()) 11840 return false; 11841 11842 // We can't evaluate the LHS; however, sometimes the result 11843 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1. 11844 // Don't ignore RHS and suppress diagnostics from this arm. 11845 SuppressRHSDiags = true; 11846 } 11847 11848 return true; 11849 } 11850 11851 assert(E->getLHS()->getType()->isIntegralOrEnumerationType() && 11852 E->getRHS()->getType()->isIntegralOrEnumerationType()); 11853 11854 if (LHSResult.Failed && !Info.noteFailure()) 11855 return false; // Ignore RHS; 11856 11857 return true; 11858 } 11859 11860 static void addOrSubLValueAsInteger(APValue &LVal, const APSInt &Index, 11861 bool IsSub) { 11862 // Compute the new offset in the appropriate width, wrapping at 64 bits. 11863 // FIXME: When compiling for a 32-bit target, we should use 32-bit 11864 // offsets. 11865 assert(!LVal.hasLValuePath() && "have designator for integer lvalue"); 11866 CharUnits &Offset = LVal.getLValueOffset(); 11867 uint64_t Offset64 = Offset.getQuantity(); 11868 uint64_t Index64 = Index.extOrTrunc(64).getZExtValue(); 11869 Offset = CharUnits::fromQuantity(IsSub ? Offset64 - Index64 11870 : Offset64 + Index64); 11871 } 11872 11873 bool DataRecursiveIntBinOpEvaluator:: 11874 VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult, 11875 const BinaryOperator *E, APValue &Result) { 11876 if (E->getOpcode() == BO_Comma) { 11877 if (RHSResult.Failed) 11878 return false; 11879 Result = RHSResult.Val; 11880 return true; 11881 } 11882 11883 if (E->isLogicalOp()) { 11884 bool lhsResult, rhsResult; 11885 bool LHSIsOK = HandleConversionToBool(LHSResult.Val, lhsResult); 11886 bool RHSIsOK = HandleConversionToBool(RHSResult.Val, rhsResult); 11887 11888 if (LHSIsOK) { 11889 if (RHSIsOK) { 11890 if (E->getOpcode() == BO_LOr) 11891 return Success(lhsResult || rhsResult, E, Result); 11892 else 11893 return Success(lhsResult && rhsResult, E, Result); 11894 } 11895 } else { 11896 if (RHSIsOK) { 11897 // We can't evaluate the LHS; however, sometimes the result 11898 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1. 11899 if (rhsResult == (E->getOpcode() == BO_LOr)) 11900 return Success(rhsResult, E, Result); 11901 } 11902 } 11903 11904 return false; 11905 } 11906 11907 assert(E->getLHS()->getType()->isIntegralOrEnumerationType() && 11908 E->getRHS()->getType()->isIntegralOrEnumerationType()); 11909 11910 if (LHSResult.Failed || RHSResult.Failed) 11911 return false; 11912 11913 const APValue &LHSVal = LHSResult.Val; 11914 const APValue &RHSVal = RHSResult.Val; 11915 11916 // Handle cases like (unsigned long)&a + 4. 11917 if (E->isAdditiveOp() && LHSVal.isLValue() && RHSVal.isInt()) { 11918 Result = LHSVal; 11919 addOrSubLValueAsInteger(Result, RHSVal.getInt(), E->getOpcode() == BO_Sub); 11920 return true; 11921 } 11922 11923 // Handle cases like 4 + (unsigned long)&a 11924 if (E->getOpcode() == BO_Add && 11925 RHSVal.isLValue() && LHSVal.isInt()) { 11926 Result = RHSVal; 11927 addOrSubLValueAsInteger(Result, LHSVal.getInt(), /*IsSub*/false); 11928 return true; 11929 } 11930 11931 if (E->getOpcode() == BO_Sub && LHSVal.isLValue() && RHSVal.isLValue()) { 11932 // Handle (intptr_t)&&A - (intptr_t)&&B. 11933 if (!LHSVal.getLValueOffset().isZero() || 11934 !RHSVal.getLValueOffset().isZero()) 11935 return false; 11936 const Expr *LHSExpr = LHSVal.getLValueBase().dyn_cast<const Expr*>(); 11937 const Expr *RHSExpr = RHSVal.getLValueBase().dyn_cast<const Expr*>(); 11938 if (!LHSExpr || !RHSExpr) 11939 return false; 11940 const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr); 11941 const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr); 11942 if (!LHSAddrExpr || !RHSAddrExpr) 11943 return false; 11944 // Make sure both labels come from the same function. 11945 if (LHSAddrExpr->getLabel()->getDeclContext() != 11946 RHSAddrExpr->getLabel()->getDeclContext()) 11947 return false; 11948 Result = APValue(LHSAddrExpr, RHSAddrExpr); 11949 return true; 11950 } 11951 11952 // All the remaining cases expect both operands to be an integer 11953 if (!LHSVal.isInt() || !RHSVal.isInt()) 11954 return Error(E); 11955 11956 // Set up the width and signedness manually, in case it can't be deduced 11957 // from the operation we're performing. 11958 // FIXME: Don't do this in the cases where we can deduce it. 11959 APSInt Value(Info.Ctx.getIntWidth(E->getType()), 11960 E->getType()->isUnsignedIntegerOrEnumerationType()); 11961 if (!handleIntIntBinOp(Info, E, LHSVal.getInt(), E->getOpcode(), 11962 RHSVal.getInt(), Value)) 11963 return false; 11964 return Success(Value, E, Result); 11965 } 11966 11967 void DataRecursiveIntBinOpEvaluator::process(EvalResult &Result) { 11968 Job &job = Queue.back(); 11969 11970 switch (job.Kind) { 11971 case Job::AnyExprKind: { 11972 if (const BinaryOperator *Bop = dyn_cast<BinaryOperator>(job.E)) { 11973 if (shouldEnqueue(Bop)) { 11974 job.Kind = Job::BinOpKind; 11975 enqueue(Bop->getLHS()); 11976 return; 11977 } 11978 } 11979 11980 EvaluateExpr(job.E, Result); 11981 Queue.pop_back(); 11982 return; 11983 } 11984 11985 case Job::BinOpKind: { 11986 const BinaryOperator *Bop = cast<BinaryOperator>(job.E); 11987 bool SuppressRHSDiags = false; 11988 if (!VisitBinOpLHSOnly(Result, Bop, SuppressRHSDiags)) { 11989 Queue.pop_back(); 11990 return; 11991 } 11992 if (SuppressRHSDiags) 11993 job.startSpeculativeEval(Info); 11994 job.LHSResult.swap(Result); 11995 job.Kind = Job::BinOpVisitedLHSKind; 11996 enqueue(Bop->getRHS()); 11997 return; 11998 } 11999 12000 case Job::BinOpVisitedLHSKind: { 12001 const BinaryOperator *Bop = cast<BinaryOperator>(job.E); 12002 EvalResult RHS; 12003 RHS.swap(Result); 12004 Result.Failed = !VisitBinOp(job.LHSResult, RHS, Bop, Result.Val); 12005 Queue.pop_back(); 12006 return; 12007 } 12008 } 12009 12010 llvm_unreachable("Invalid Job::Kind!"); 12011 } 12012 12013 namespace { 12014 /// Used when we determine that we should fail, but can keep evaluating prior to 12015 /// noting that we had a failure. 12016 class DelayedNoteFailureRAII { 12017 EvalInfo &Info; 12018 bool NoteFailure; 12019 12020 public: 12021 DelayedNoteFailureRAII(EvalInfo &Info, bool NoteFailure = true) 12022 : Info(Info), NoteFailure(NoteFailure) {} 12023 ~DelayedNoteFailureRAII() { 12024 if (NoteFailure) { 12025 bool ContinueAfterFailure = Info.noteFailure(); 12026 (void)ContinueAfterFailure; 12027 assert(ContinueAfterFailure && 12028 "Shouldn't have kept evaluating on failure."); 12029 } 12030 } 12031 }; 12032 12033 enum class CmpResult { 12034 Unequal, 12035 Less, 12036 Equal, 12037 Greater, 12038 Unordered, 12039 }; 12040 } 12041 12042 template <class SuccessCB, class AfterCB> 12043 static bool 12044 EvaluateComparisonBinaryOperator(EvalInfo &Info, const BinaryOperator *E, 12045 SuccessCB &&Success, AfterCB &&DoAfter) { 12046 assert(E->isComparisonOp() && "expected comparison operator"); 12047 assert((E->getOpcode() == BO_Cmp || 12048 E->getType()->isIntegralOrEnumerationType()) && 12049 "unsupported binary expression evaluation"); 12050 auto Error = [&](const Expr *E) { 12051 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr); 12052 return false; 12053 }; 12054 12055 bool IsRelational = E->isRelationalOp() || E->getOpcode() == BO_Cmp; 12056 bool IsEquality = E->isEqualityOp(); 12057 12058 QualType LHSTy = E->getLHS()->getType(); 12059 QualType RHSTy = E->getRHS()->getType(); 12060 12061 if (LHSTy->isIntegralOrEnumerationType() && 12062 RHSTy->isIntegralOrEnumerationType()) { 12063 APSInt LHS, RHS; 12064 bool LHSOK = EvaluateInteger(E->getLHS(), LHS, Info); 12065 if (!LHSOK && !Info.noteFailure()) 12066 return false; 12067 if (!EvaluateInteger(E->getRHS(), RHS, Info) || !LHSOK) 12068 return false; 12069 if (LHS < RHS) 12070 return Success(CmpResult::Less, E); 12071 if (LHS > RHS) 12072 return Success(CmpResult::Greater, E); 12073 return Success(CmpResult::Equal, E); 12074 } 12075 12076 if (LHSTy->isFixedPointType() || RHSTy->isFixedPointType()) { 12077 APFixedPoint LHSFX(Info.Ctx.getFixedPointSemantics(LHSTy)); 12078 APFixedPoint RHSFX(Info.Ctx.getFixedPointSemantics(RHSTy)); 12079 12080 bool LHSOK = EvaluateFixedPointOrInteger(E->getLHS(), LHSFX, Info); 12081 if (!LHSOK && !Info.noteFailure()) 12082 return false; 12083 if (!EvaluateFixedPointOrInteger(E->getRHS(), RHSFX, Info) || !LHSOK) 12084 return false; 12085 if (LHSFX < RHSFX) 12086 return Success(CmpResult::Less, E); 12087 if (LHSFX > RHSFX) 12088 return Success(CmpResult::Greater, E); 12089 return Success(CmpResult::Equal, E); 12090 } 12091 12092 if (LHSTy->isAnyComplexType() || RHSTy->isAnyComplexType()) { 12093 ComplexValue LHS, RHS; 12094 bool LHSOK; 12095 if (E->isAssignmentOp()) { 12096 LValue LV; 12097 EvaluateLValue(E->getLHS(), LV, Info); 12098 LHSOK = false; 12099 } else if (LHSTy->isRealFloatingType()) { 12100 LHSOK = EvaluateFloat(E->getLHS(), LHS.FloatReal, Info); 12101 if (LHSOK) { 12102 LHS.makeComplexFloat(); 12103 LHS.FloatImag = APFloat(LHS.FloatReal.getSemantics()); 12104 } 12105 } else { 12106 LHSOK = EvaluateComplex(E->getLHS(), LHS, Info); 12107 } 12108 if (!LHSOK && !Info.noteFailure()) 12109 return false; 12110 12111 if (E->getRHS()->getType()->isRealFloatingType()) { 12112 if (!EvaluateFloat(E->getRHS(), RHS.FloatReal, Info) || !LHSOK) 12113 return false; 12114 RHS.makeComplexFloat(); 12115 RHS.FloatImag = APFloat(RHS.FloatReal.getSemantics()); 12116 } else if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK) 12117 return false; 12118 12119 if (LHS.isComplexFloat()) { 12120 APFloat::cmpResult CR_r = 12121 LHS.getComplexFloatReal().compare(RHS.getComplexFloatReal()); 12122 APFloat::cmpResult CR_i = 12123 LHS.getComplexFloatImag().compare(RHS.getComplexFloatImag()); 12124 bool IsEqual = CR_r == APFloat::cmpEqual && CR_i == APFloat::cmpEqual; 12125 return Success(IsEqual ? CmpResult::Equal : CmpResult::Unequal, E); 12126 } else { 12127 assert(IsEquality && "invalid complex comparison"); 12128 bool IsEqual = LHS.getComplexIntReal() == RHS.getComplexIntReal() && 12129 LHS.getComplexIntImag() == RHS.getComplexIntImag(); 12130 return Success(IsEqual ? CmpResult::Equal : CmpResult::Unequal, E); 12131 } 12132 } 12133 12134 if (LHSTy->isRealFloatingType() && 12135 RHSTy->isRealFloatingType()) { 12136 APFloat RHS(0.0), LHS(0.0); 12137 12138 bool LHSOK = EvaluateFloat(E->getRHS(), RHS, Info); 12139 if (!LHSOK && !Info.noteFailure()) 12140 return false; 12141 12142 if (!EvaluateFloat(E->getLHS(), LHS, Info) || !LHSOK) 12143 return false; 12144 12145 assert(E->isComparisonOp() && "Invalid binary operator!"); 12146 auto GetCmpRes = [&]() { 12147 switch (LHS.compare(RHS)) { 12148 case APFloat::cmpEqual: 12149 return CmpResult::Equal; 12150 case APFloat::cmpLessThan: 12151 return CmpResult::Less; 12152 case APFloat::cmpGreaterThan: 12153 return CmpResult::Greater; 12154 case APFloat::cmpUnordered: 12155 return CmpResult::Unordered; 12156 } 12157 llvm_unreachable("Unrecognised APFloat::cmpResult enum"); 12158 }; 12159 return Success(GetCmpRes(), E); 12160 } 12161 12162 if (LHSTy->isPointerType() && RHSTy->isPointerType()) { 12163 LValue LHSValue, RHSValue; 12164 12165 bool LHSOK = EvaluatePointer(E->getLHS(), LHSValue, Info); 12166 if (!LHSOK && !Info.noteFailure()) 12167 return false; 12168 12169 if (!EvaluatePointer(E->getRHS(), RHSValue, Info) || !LHSOK) 12170 return false; 12171 12172 // Reject differing bases from the normal codepath; we special-case 12173 // comparisons to null. 12174 if (!HasSameBase(LHSValue, RHSValue)) { 12175 // Inequalities and subtractions between unrelated pointers have 12176 // unspecified or undefined behavior. 12177 if (!IsEquality) { 12178 Info.FFDiag(E, diag::note_constexpr_pointer_comparison_unspecified); 12179 return false; 12180 } 12181 // A constant address may compare equal to the address of a symbol. 12182 // The one exception is that address of an object cannot compare equal 12183 // to a null pointer constant. 12184 if ((!LHSValue.Base && !LHSValue.Offset.isZero()) || 12185 (!RHSValue.Base && !RHSValue.Offset.isZero())) 12186 return Error(E); 12187 // It's implementation-defined whether distinct literals will have 12188 // distinct addresses. In clang, the result of such a comparison is 12189 // unspecified, so it is not a constant expression. However, we do know 12190 // that the address of a literal will be non-null. 12191 if ((IsLiteralLValue(LHSValue) || IsLiteralLValue(RHSValue)) && 12192 LHSValue.Base && RHSValue.Base) 12193 return Error(E); 12194 // We can't tell whether weak symbols will end up pointing to the same 12195 // object. 12196 if (IsWeakLValue(LHSValue) || IsWeakLValue(RHSValue)) 12197 return Error(E); 12198 // We can't compare the address of the start of one object with the 12199 // past-the-end address of another object, per C++ DR1652. 12200 if ((LHSValue.Base && LHSValue.Offset.isZero() && 12201 isOnePastTheEndOfCompleteObject(Info.Ctx, RHSValue)) || 12202 (RHSValue.Base && RHSValue.Offset.isZero() && 12203 isOnePastTheEndOfCompleteObject(Info.Ctx, LHSValue))) 12204 return Error(E); 12205 // We can't tell whether an object is at the same address as another 12206 // zero sized object. 12207 if ((RHSValue.Base && isZeroSized(LHSValue)) || 12208 (LHSValue.Base && isZeroSized(RHSValue))) 12209 return Error(E); 12210 return Success(CmpResult::Unequal, E); 12211 } 12212 12213 const CharUnits &LHSOffset = LHSValue.getLValueOffset(); 12214 const CharUnits &RHSOffset = RHSValue.getLValueOffset(); 12215 12216 SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator(); 12217 SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator(); 12218 12219 // C++11 [expr.rel]p3: 12220 // Pointers to void (after pointer conversions) can be compared, with a 12221 // result defined as follows: If both pointers represent the same 12222 // address or are both the null pointer value, the result is true if the 12223 // operator is <= or >= and false otherwise; otherwise the result is 12224 // unspecified. 12225 // We interpret this as applying to pointers to *cv* void. 12226 if (LHSTy->isVoidPointerType() && LHSOffset != RHSOffset && IsRelational) 12227 Info.CCEDiag(E, diag::note_constexpr_void_comparison); 12228 12229 // C++11 [expr.rel]p2: 12230 // - If two pointers point to non-static data members of the same object, 12231 // or to subobjects or array elements fo such members, recursively, the 12232 // pointer to the later declared member compares greater provided the 12233 // two members have the same access control and provided their class is 12234 // not a union. 12235 // [...] 12236 // - Otherwise pointer comparisons are unspecified. 12237 if (!LHSDesignator.Invalid && !RHSDesignator.Invalid && IsRelational) { 12238 bool WasArrayIndex; 12239 unsigned Mismatch = FindDesignatorMismatch( 12240 getType(LHSValue.Base), LHSDesignator, RHSDesignator, WasArrayIndex); 12241 // At the point where the designators diverge, the comparison has a 12242 // specified value if: 12243 // - we are comparing array indices 12244 // - we are comparing fields of a union, or fields with the same access 12245 // Otherwise, the result is unspecified and thus the comparison is not a 12246 // constant expression. 12247 if (!WasArrayIndex && Mismatch < LHSDesignator.Entries.size() && 12248 Mismatch < RHSDesignator.Entries.size()) { 12249 const FieldDecl *LF = getAsField(LHSDesignator.Entries[Mismatch]); 12250 const FieldDecl *RF = getAsField(RHSDesignator.Entries[Mismatch]); 12251 if (!LF && !RF) 12252 Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_classes); 12253 else if (!LF) 12254 Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field) 12255 << getAsBaseClass(LHSDesignator.Entries[Mismatch]) 12256 << RF->getParent() << RF; 12257 else if (!RF) 12258 Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field) 12259 << getAsBaseClass(RHSDesignator.Entries[Mismatch]) 12260 << LF->getParent() << LF; 12261 else if (!LF->getParent()->isUnion() && 12262 LF->getAccess() != RF->getAccess()) 12263 Info.CCEDiag(E, 12264 diag::note_constexpr_pointer_comparison_differing_access) 12265 << LF << LF->getAccess() << RF << RF->getAccess() 12266 << LF->getParent(); 12267 } 12268 } 12269 12270 // The comparison here must be unsigned, and performed with the same 12271 // width as the pointer. 12272 unsigned PtrSize = Info.Ctx.getTypeSize(LHSTy); 12273 uint64_t CompareLHS = LHSOffset.getQuantity(); 12274 uint64_t CompareRHS = RHSOffset.getQuantity(); 12275 assert(PtrSize <= 64 && "Unexpected pointer width"); 12276 uint64_t Mask = ~0ULL >> (64 - PtrSize); 12277 CompareLHS &= Mask; 12278 CompareRHS &= Mask; 12279 12280 // If there is a base and this is a relational operator, we can only 12281 // compare pointers within the object in question; otherwise, the result 12282 // depends on where the object is located in memory. 12283 if (!LHSValue.Base.isNull() && IsRelational) { 12284 QualType BaseTy = getType(LHSValue.Base); 12285 if (BaseTy->isIncompleteType()) 12286 return Error(E); 12287 CharUnits Size = Info.Ctx.getTypeSizeInChars(BaseTy); 12288 uint64_t OffsetLimit = Size.getQuantity(); 12289 if (CompareLHS > OffsetLimit || CompareRHS > OffsetLimit) 12290 return Error(E); 12291 } 12292 12293 if (CompareLHS < CompareRHS) 12294 return Success(CmpResult::Less, E); 12295 if (CompareLHS > CompareRHS) 12296 return Success(CmpResult::Greater, E); 12297 return Success(CmpResult::Equal, E); 12298 } 12299 12300 if (LHSTy->isMemberPointerType()) { 12301 assert(IsEquality && "unexpected member pointer operation"); 12302 assert(RHSTy->isMemberPointerType() && "invalid comparison"); 12303 12304 MemberPtr LHSValue, RHSValue; 12305 12306 bool LHSOK = EvaluateMemberPointer(E->getLHS(), LHSValue, Info); 12307 if (!LHSOK && !Info.noteFailure()) 12308 return false; 12309 12310 if (!EvaluateMemberPointer(E->getRHS(), RHSValue, Info) || !LHSOK) 12311 return false; 12312 12313 // C++11 [expr.eq]p2: 12314 // If both operands are null, they compare equal. Otherwise if only one is 12315 // null, they compare unequal. 12316 if (!LHSValue.getDecl() || !RHSValue.getDecl()) { 12317 bool Equal = !LHSValue.getDecl() && !RHSValue.getDecl(); 12318 return Success(Equal ? CmpResult::Equal : CmpResult::Unequal, E); 12319 } 12320 12321 // Otherwise if either is a pointer to a virtual member function, the 12322 // result is unspecified. 12323 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(LHSValue.getDecl())) 12324 if (MD->isVirtual()) 12325 Info.CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD; 12326 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(RHSValue.getDecl())) 12327 if (MD->isVirtual()) 12328 Info.CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD; 12329 12330 // Otherwise they compare equal if and only if they would refer to the 12331 // same member of the same most derived object or the same subobject if 12332 // they were dereferenced with a hypothetical object of the associated 12333 // class type. 12334 bool Equal = LHSValue == RHSValue; 12335 return Success(Equal ? CmpResult::Equal : CmpResult::Unequal, E); 12336 } 12337 12338 if (LHSTy->isNullPtrType()) { 12339 assert(E->isComparisonOp() && "unexpected nullptr operation"); 12340 assert(RHSTy->isNullPtrType() && "missing pointer conversion"); 12341 // C++11 [expr.rel]p4, [expr.eq]p3: If two operands of type std::nullptr_t 12342 // are compared, the result is true of the operator is <=, >= or ==, and 12343 // false otherwise. 12344 return Success(CmpResult::Equal, E); 12345 } 12346 12347 return DoAfter(); 12348 } 12349 12350 bool RecordExprEvaluator::VisitBinCmp(const BinaryOperator *E) { 12351 if (!CheckLiteralType(Info, E)) 12352 return false; 12353 12354 auto OnSuccess = [&](CmpResult CR, const BinaryOperator *E) { 12355 ComparisonCategoryResult CCR; 12356 switch (CR) { 12357 case CmpResult::Unequal: 12358 llvm_unreachable("should never produce Unequal for three-way comparison"); 12359 case CmpResult::Less: 12360 CCR = ComparisonCategoryResult::Less; 12361 break; 12362 case CmpResult::Equal: 12363 CCR = ComparisonCategoryResult::Equal; 12364 break; 12365 case CmpResult::Greater: 12366 CCR = ComparisonCategoryResult::Greater; 12367 break; 12368 case CmpResult::Unordered: 12369 CCR = ComparisonCategoryResult::Unordered; 12370 break; 12371 } 12372 // Evaluation succeeded. Lookup the information for the comparison category 12373 // type and fetch the VarDecl for the result. 12374 const ComparisonCategoryInfo &CmpInfo = 12375 Info.Ctx.CompCategories.getInfoForType(E->getType()); 12376 const VarDecl *VD = CmpInfo.getValueInfo(CmpInfo.makeWeakResult(CCR))->VD; 12377 // Check and evaluate the result as a constant expression. 12378 LValue LV; 12379 LV.set(VD); 12380 if (!handleLValueToRValueConversion(Info, E, E->getType(), LV, Result)) 12381 return false; 12382 return CheckConstantExpression(Info, E->getExprLoc(), E->getType(), Result); 12383 }; 12384 return EvaluateComparisonBinaryOperator(Info, E, OnSuccess, [&]() { 12385 return ExprEvaluatorBaseTy::VisitBinCmp(E); 12386 }); 12387 } 12388 12389 bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { 12390 // We don't call noteFailure immediately because the assignment happens after 12391 // we evaluate LHS and RHS. 12392 if (!Info.keepEvaluatingAfterFailure() && E->isAssignmentOp()) 12393 return Error(E); 12394 12395 DelayedNoteFailureRAII MaybeNoteFailureLater(Info, E->isAssignmentOp()); 12396 if (DataRecursiveIntBinOpEvaluator::shouldEnqueue(E)) 12397 return DataRecursiveIntBinOpEvaluator(*this, Result).Traverse(E); 12398 12399 assert((!E->getLHS()->getType()->isIntegralOrEnumerationType() || 12400 !E->getRHS()->getType()->isIntegralOrEnumerationType()) && 12401 "DataRecursiveIntBinOpEvaluator should have handled integral types"); 12402 12403 if (E->isComparisonOp()) { 12404 // Evaluate builtin binary comparisons by evaluating them as three-way 12405 // comparisons and then translating the result. 12406 auto OnSuccess = [&](CmpResult CR, const BinaryOperator *E) { 12407 assert((CR != CmpResult::Unequal || E->isEqualityOp()) && 12408 "should only produce Unequal for equality comparisons"); 12409 bool IsEqual = CR == CmpResult::Equal, 12410 IsLess = CR == CmpResult::Less, 12411 IsGreater = CR == CmpResult::Greater; 12412 auto Op = E->getOpcode(); 12413 switch (Op) { 12414 default: 12415 llvm_unreachable("unsupported binary operator"); 12416 case BO_EQ: 12417 case BO_NE: 12418 return Success(IsEqual == (Op == BO_EQ), E); 12419 case BO_LT: 12420 return Success(IsLess, E); 12421 case BO_GT: 12422 return Success(IsGreater, E); 12423 case BO_LE: 12424 return Success(IsEqual || IsLess, E); 12425 case BO_GE: 12426 return Success(IsEqual || IsGreater, E); 12427 } 12428 }; 12429 return EvaluateComparisonBinaryOperator(Info, E, OnSuccess, [&]() { 12430 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 12431 }); 12432 } 12433 12434 QualType LHSTy = E->getLHS()->getType(); 12435 QualType RHSTy = E->getRHS()->getType(); 12436 12437 if (LHSTy->isPointerType() && RHSTy->isPointerType() && 12438 E->getOpcode() == BO_Sub) { 12439 LValue LHSValue, RHSValue; 12440 12441 bool LHSOK = EvaluatePointer(E->getLHS(), LHSValue, Info); 12442 if (!LHSOK && !Info.noteFailure()) 12443 return false; 12444 12445 if (!EvaluatePointer(E->getRHS(), RHSValue, Info) || !LHSOK) 12446 return false; 12447 12448 // Reject differing bases from the normal codepath; we special-case 12449 // comparisons to null. 12450 if (!HasSameBase(LHSValue, RHSValue)) { 12451 // Handle &&A - &&B. 12452 if (!LHSValue.Offset.isZero() || !RHSValue.Offset.isZero()) 12453 return Error(E); 12454 const Expr *LHSExpr = LHSValue.Base.dyn_cast<const Expr *>(); 12455 const Expr *RHSExpr = RHSValue.Base.dyn_cast<const Expr *>(); 12456 if (!LHSExpr || !RHSExpr) 12457 return Error(E); 12458 const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr); 12459 const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr); 12460 if (!LHSAddrExpr || !RHSAddrExpr) 12461 return Error(E); 12462 // Make sure both labels come from the same function. 12463 if (LHSAddrExpr->getLabel()->getDeclContext() != 12464 RHSAddrExpr->getLabel()->getDeclContext()) 12465 return Error(E); 12466 return Success(APValue(LHSAddrExpr, RHSAddrExpr), E); 12467 } 12468 const CharUnits &LHSOffset = LHSValue.getLValueOffset(); 12469 const CharUnits &RHSOffset = RHSValue.getLValueOffset(); 12470 12471 SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator(); 12472 SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator(); 12473 12474 // C++11 [expr.add]p6: 12475 // Unless both pointers point to elements of the same array object, or 12476 // one past the last element of the array object, the behavior is 12477 // undefined. 12478 if (!LHSDesignator.Invalid && !RHSDesignator.Invalid && 12479 !AreElementsOfSameArray(getType(LHSValue.Base), LHSDesignator, 12480 RHSDesignator)) 12481 Info.CCEDiag(E, diag::note_constexpr_pointer_subtraction_not_same_array); 12482 12483 QualType Type = E->getLHS()->getType(); 12484 QualType ElementType = Type->castAs<PointerType>()->getPointeeType(); 12485 12486 CharUnits ElementSize; 12487 if (!HandleSizeof(Info, E->getExprLoc(), ElementType, ElementSize)) 12488 return false; 12489 12490 // As an extension, a type may have zero size (empty struct or union in 12491 // C, array of zero length). Pointer subtraction in such cases has 12492 // undefined behavior, so is not constant. 12493 if (ElementSize.isZero()) { 12494 Info.FFDiag(E, diag::note_constexpr_pointer_subtraction_zero_size) 12495 << ElementType; 12496 return false; 12497 } 12498 12499 // FIXME: LLVM and GCC both compute LHSOffset - RHSOffset at runtime, 12500 // and produce incorrect results when it overflows. Such behavior 12501 // appears to be non-conforming, but is common, so perhaps we should 12502 // assume the standard intended for such cases to be undefined behavior 12503 // and check for them. 12504 12505 // Compute (LHSOffset - RHSOffset) / Size carefully, checking for 12506 // overflow in the final conversion to ptrdiff_t. 12507 APSInt LHS(llvm::APInt(65, (int64_t)LHSOffset.getQuantity(), true), false); 12508 APSInt RHS(llvm::APInt(65, (int64_t)RHSOffset.getQuantity(), true), false); 12509 APSInt ElemSize(llvm::APInt(65, (int64_t)ElementSize.getQuantity(), true), 12510 false); 12511 APSInt TrueResult = (LHS - RHS) / ElemSize; 12512 APSInt Result = TrueResult.trunc(Info.Ctx.getIntWidth(E->getType())); 12513 12514 if (Result.extend(65) != TrueResult && 12515 !HandleOverflow(Info, E, TrueResult, E->getType())) 12516 return false; 12517 return Success(Result, E); 12518 } 12519 12520 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 12521 } 12522 12523 /// VisitUnaryExprOrTypeTraitExpr - Evaluate a sizeof, alignof or vec_step with 12524 /// a result as the expression's type. 12525 bool IntExprEvaluator::VisitUnaryExprOrTypeTraitExpr( 12526 const UnaryExprOrTypeTraitExpr *E) { 12527 switch(E->getKind()) { 12528 case UETT_PreferredAlignOf: 12529 case UETT_AlignOf: { 12530 if (E->isArgumentType()) 12531 return Success(GetAlignOfType(Info, E->getArgumentType(), E->getKind()), 12532 E); 12533 else 12534 return Success(GetAlignOfExpr(Info, E->getArgumentExpr(), E->getKind()), 12535 E); 12536 } 12537 12538 case UETT_VecStep: { 12539 QualType Ty = E->getTypeOfArgument(); 12540 12541 if (Ty->isVectorType()) { 12542 unsigned n = Ty->castAs<VectorType>()->getNumElements(); 12543 12544 // The vec_step built-in functions that take a 3-component 12545 // vector return 4. (OpenCL 1.1 spec 6.11.12) 12546 if (n == 3) 12547 n = 4; 12548 12549 return Success(n, E); 12550 } else 12551 return Success(1, E); 12552 } 12553 12554 case UETT_SizeOf: { 12555 QualType SrcTy = E->getTypeOfArgument(); 12556 // C++ [expr.sizeof]p2: "When applied to a reference or a reference type, 12557 // the result is the size of the referenced type." 12558 if (const ReferenceType *Ref = SrcTy->getAs<ReferenceType>()) 12559 SrcTy = Ref->getPointeeType(); 12560 12561 CharUnits Sizeof; 12562 if (!HandleSizeof(Info, E->getExprLoc(), SrcTy, Sizeof)) 12563 return false; 12564 return Success(Sizeof, E); 12565 } 12566 case UETT_OpenMPRequiredSimdAlign: 12567 assert(E->isArgumentType()); 12568 return Success( 12569 Info.Ctx.toCharUnitsFromBits( 12570 Info.Ctx.getOpenMPDefaultSimdAlign(E->getArgumentType())) 12571 .getQuantity(), 12572 E); 12573 } 12574 12575 llvm_unreachable("unknown expr/type trait"); 12576 } 12577 12578 bool IntExprEvaluator::VisitOffsetOfExpr(const OffsetOfExpr *OOE) { 12579 CharUnits Result; 12580 unsigned n = OOE->getNumComponents(); 12581 if (n == 0) 12582 return Error(OOE); 12583 QualType CurrentType = OOE->getTypeSourceInfo()->getType(); 12584 for (unsigned i = 0; i != n; ++i) { 12585 OffsetOfNode ON = OOE->getComponent(i); 12586 switch (ON.getKind()) { 12587 case OffsetOfNode::Array: { 12588 const Expr *Idx = OOE->getIndexExpr(ON.getArrayExprIndex()); 12589 APSInt IdxResult; 12590 if (!EvaluateInteger(Idx, IdxResult, Info)) 12591 return false; 12592 const ArrayType *AT = Info.Ctx.getAsArrayType(CurrentType); 12593 if (!AT) 12594 return Error(OOE); 12595 CurrentType = AT->getElementType(); 12596 CharUnits ElementSize = Info.Ctx.getTypeSizeInChars(CurrentType); 12597 Result += IdxResult.getSExtValue() * ElementSize; 12598 break; 12599 } 12600 12601 case OffsetOfNode::Field: { 12602 FieldDecl *MemberDecl = ON.getField(); 12603 const RecordType *RT = CurrentType->getAs<RecordType>(); 12604 if (!RT) 12605 return Error(OOE); 12606 RecordDecl *RD = RT->getDecl(); 12607 if (RD->isInvalidDecl()) return false; 12608 const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD); 12609 unsigned i = MemberDecl->getFieldIndex(); 12610 assert(i < RL.getFieldCount() && "offsetof field in wrong type"); 12611 Result += Info.Ctx.toCharUnitsFromBits(RL.getFieldOffset(i)); 12612 CurrentType = MemberDecl->getType().getNonReferenceType(); 12613 break; 12614 } 12615 12616 case OffsetOfNode::Identifier: 12617 llvm_unreachable("dependent __builtin_offsetof"); 12618 12619 case OffsetOfNode::Base: { 12620 CXXBaseSpecifier *BaseSpec = ON.getBase(); 12621 if (BaseSpec->isVirtual()) 12622 return Error(OOE); 12623 12624 // Find the layout of the class whose base we are looking into. 12625 const RecordType *RT = CurrentType->getAs<RecordType>(); 12626 if (!RT) 12627 return Error(OOE); 12628 RecordDecl *RD = RT->getDecl(); 12629 if (RD->isInvalidDecl()) return false; 12630 const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD); 12631 12632 // Find the base class itself. 12633 CurrentType = BaseSpec->getType(); 12634 const RecordType *BaseRT = CurrentType->getAs<RecordType>(); 12635 if (!BaseRT) 12636 return Error(OOE); 12637 12638 // Add the offset to the base. 12639 Result += RL.getBaseClassOffset(cast<CXXRecordDecl>(BaseRT->getDecl())); 12640 break; 12641 } 12642 } 12643 } 12644 return Success(Result, OOE); 12645 } 12646 12647 bool IntExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) { 12648 switch (E->getOpcode()) { 12649 default: 12650 // Address, indirect, pre/post inc/dec, etc are not valid constant exprs. 12651 // See C99 6.6p3. 12652 return Error(E); 12653 case UO_Extension: 12654 // FIXME: Should extension allow i-c-e extension expressions in its scope? 12655 // If so, we could clear the diagnostic ID. 12656 return Visit(E->getSubExpr()); 12657 case UO_Plus: 12658 // The result is just the value. 12659 return Visit(E->getSubExpr()); 12660 case UO_Minus: { 12661 if (!Visit(E->getSubExpr())) 12662 return false; 12663 if (!Result.isInt()) return Error(E); 12664 const APSInt &Value = Result.getInt(); 12665 if (Value.isSigned() && Value.isMinSignedValue() && E->canOverflow() && 12666 !HandleOverflow(Info, E, -Value.extend(Value.getBitWidth() + 1), 12667 E->getType())) 12668 return false; 12669 return Success(-Value, E); 12670 } 12671 case UO_Not: { 12672 if (!Visit(E->getSubExpr())) 12673 return false; 12674 if (!Result.isInt()) return Error(E); 12675 return Success(~Result.getInt(), E); 12676 } 12677 case UO_LNot: { 12678 bool bres; 12679 if (!EvaluateAsBooleanCondition(E->getSubExpr(), bres, Info)) 12680 return false; 12681 return Success(!bres, E); 12682 } 12683 } 12684 } 12685 12686 /// HandleCast - This is used to evaluate implicit or explicit casts where the 12687 /// result type is integer. 12688 bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) { 12689 const Expr *SubExpr = E->getSubExpr(); 12690 QualType DestType = E->getType(); 12691 QualType SrcType = SubExpr->getType(); 12692 12693 switch (E->getCastKind()) { 12694 case CK_BaseToDerived: 12695 case CK_DerivedToBase: 12696 case CK_UncheckedDerivedToBase: 12697 case CK_Dynamic: 12698 case CK_ToUnion: 12699 case CK_ArrayToPointerDecay: 12700 case CK_FunctionToPointerDecay: 12701 case CK_NullToPointer: 12702 case CK_NullToMemberPointer: 12703 case CK_BaseToDerivedMemberPointer: 12704 case CK_DerivedToBaseMemberPointer: 12705 case CK_ReinterpretMemberPointer: 12706 case CK_ConstructorConversion: 12707 case CK_IntegralToPointer: 12708 case CK_ToVoid: 12709 case CK_VectorSplat: 12710 case CK_IntegralToFloating: 12711 case CK_FloatingCast: 12712 case CK_CPointerToObjCPointerCast: 12713 case CK_BlockPointerToObjCPointerCast: 12714 case CK_AnyPointerToBlockPointerCast: 12715 case CK_ObjCObjectLValueCast: 12716 case CK_FloatingRealToComplex: 12717 case CK_FloatingComplexToReal: 12718 case CK_FloatingComplexCast: 12719 case CK_FloatingComplexToIntegralComplex: 12720 case CK_IntegralRealToComplex: 12721 case CK_IntegralComplexCast: 12722 case CK_IntegralComplexToFloatingComplex: 12723 case CK_BuiltinFnToFnPtr: 12724 case CK_ZeroToOCLOpaqueType: 12725 case CK_NonAtomicToAtomic: 12726 case CK_AddressSpaceConversion: 12727 case CK_IntToOCLSampler: 12728 case CK_FixedPointCast: 12729 case CK_IntegralToFixedPoint: 12730 llvm_unreachable("invalid cast kind for integral value"); 12731 12732 case CK_BitCast: 12733 case CK_Dependent: 12734 case CK_LValueBitCast: 12735 case CK_ARCProduceObject: 12736 case CK_ARCConsumeObject: 12737 case CK_ARCReclaimReturnedObject: 12738 case CK_ARCExtendBlockObject: 12739 case CK_CopyAndAutoreleaseBlockObject: 12740 return Error(E); 12741 12742 case CK_UserDefinedConversion: 12743 case CK_LValueToRValue: 12744 case CK_AtomicToNonAtomic: 12745 case CK_NoOp: 12746 case CK_LValueToRValueBitCast: 12747 return ExprEvaluatorBaseTy::VisitCastExpr(E); 12748 12749 case CK_MemberPointerToBoolean: 12750 case CK_PointerToBoolean: 12751 case CK_IntegralToBoolean: 12752 case CK_FloatingToBoolean: 12753 case CK_BooleanToSignedIntegral: 12754 case CK_FloatingComplexToBoolean: 12755 case CK_IntegralComplexToBoolean: { 12756 bool BoolResult; 12757 if (!EvaluateAsBooleanCondition(SubExpr, BoolResult, Info)) 12758 return false; 12759 uint64_t IntResult = BoolResult; 12760 if (BoolResult && E->getCastKind() == CK_BooleanToSignedIntegral) 12761 IntResult = (uint64_t)-1; 12762 return Success(IntResult, E); 12763 } 12764 12765 case CK_FixedPointToIntegral: { 12766 APFixedPoint Src(Info.Ctx.getFixedPointSemantics(SrcType)); 12767 if (!EvaluateFixedPoint(SubExpr, Src, Info)) 12768 return false; 12769 bool Overflowed; 12770 llvm::APSInt Result = Src.convertToInt( 12771 Info.Ctx.getIntWidth(DestType), 12772 DestType->isSignedIntegerOrEnumerationType(), &Overflowed); 12773 if (Overflowed && !HandleOverflow(Info, E, Result, DestType)) 12774 return false; 12775 return Success(Result, E); 12776 } 12777 12778 case CK_FixedPointToBoolean: { 12779 // Unsigned padding does not affect this. 12780 APValue Val; 12781 if (!Evaluate(Val, Info, SubExpr)) 12782 return false; 12783 return Success(Val.getFixedPoint().getBoolValue(), E); 12784 } 12785 12786 case CK_IntegralCast: { 12787 if (!Visit(SubExpr)) 12788 return false; 12789 12790 if (!Result.isInt()) { 12791 // Allow casts of address-of-label differences if they are no-ops 12792 // or narrowing. (The narrowing case isn't actually guaranteed to 12793 // be constant-evaluatable except in some narrow cases which are hard 12794 // to detect here. We let it through on the assumption the user knows 12795 // what they are doing.) 12796 if (Result.isAddrLabelDiff()) 12797 return Info.Ctx.getTypeSize(DestType) <= Info.Ctx.getTypeSize(SrcType); 12798 // Only allow casts of lvalues if they are lossless. 12799 return Info.Ctx.getTypeSize(DestType) == Info.Ctx.getTypeSize(SrcType); 12800 } 12801 12802 return Success(HandleIntToIntCast(Info, E, DestType, SrcType, 12803 Result.getInt()), E); 12804 } 12805 12806 case CK_PointerToIntegral: { 12807 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2; 12808 12809 LValue LV; 12810 if (!EvaluatePointer(SubExpr, LV, Info)) 12811 return false; 12812 12813 if (LV.getLValueBase()) { 12814 // Only allow based lvalue casts if they are lossless. 12815 // FIXME: Allow a larger integer size than the pointer size, and allow 12816 // narrowing back down to pointer width in subsequent integral casts. 12817 // FIXME: Check integer type's active bits, not its type size. 12818 if (Info.Ctx.getTypeSize(DestType) != Info.Ctx.getTypeSize(SrcType)) 12819 return Error(E); 12820 12821 LV.Designator.setInvalid(); 12822 LV.moveInto(Result); 12823 return true; 12824 } 12825 12826 APSInt AsInt; 12827 APValue V; 12828 LV.moveInto(V); 12829 if (!V.toIntegralConstant(AsInt, SrcType, Info.Ctx)) 12830 llvm_unreachable("Can't cast this!"); 12831 12832 return Success(HandleIntToIntCast(Info, E, DestType, SrcType, AsInt), E); 12833 } 12834 12835 case CK_IntegralComplexToReal: { 12836 ComplexValue C; 12837 if (!EvaluateComplex(SubExpr, C, Info)) 12838 return false; 12839 return Success(C.getComplexIntReal(), E); 12840 } 12841 12842 case CK_FloatingToIntegral: { 12843 APFloat F(0.0); 12844 if (!EvaluateFloat(SubExpr, F, Info)) 12845 return false; 12846 12847 APSInt Value; 12848 if (!HandleFloatToIntCast(Info, E, SrcType, F, DestType, Value)) 12849 return false; 12850 return Success(Value, E); 12851 } 12852 } 12853 12854 llvm_unreachable("unknown cast resulting in integral value"); 12855 } 12856 12857 bool IntExprEvaluator::VisitUnaryReal(const UnaryOperator *E) { 12858 if (E->getSubExpr()->getType()->isAnyComplexType()) { 12859 ComplexValue LV; 12860 if (!EvaluateComplex(E->getSubExpr(), LV, Info)) 12861 return false; 12862 if (!LV.isComplexInt()) 12863 return Error(E); 12864 return Success(LV.getComplexIntReal(), E); 12865 } 12866 12867 return Visit(E->getSubExpr()); 12868 } 12869 12870 bool IntExprEvaluator::VisitUnaryImag(const UnaryOperator *E) { 12871 if (E->getSubExpr()->getType()->isComplexIntegerType()) { 12872 ComplexValue LV; 12873 if (!EvaluateComplex(E->getSubExpr(), LV, Info)) 12874 return false; 12875 if (!LV.isComplexInt()) 12876 return Error(E); 12877 return Success(LV.getComplexIntImag(), E); 12878 } 12879 12880 VisitIgnoredValue(E->getSubExpr()); 12881 return Success(0, E); 12882 } 12883 12884 bool IntExprEvaluator::VisitSizeOfPackExpr(const SizeOfPackExpr *E) { 12885 return Success(E->getPackLength(), E); 12886 } 12887 12888 bool IntExprEvaluator::VisitCXXNoexceptExpr(const CXXNoexceptExpr *E) { 12889 return Success(E->getValue(), E); 12890 } 12891 12892 bool IntExprEvaluator::VisitConceptSpecializationExpr( 12893 const ConceptSpecializationExpr *E) { 12894 return Success(E->isSatisfied(), E); 12895 } 12896 12897 bool IntExprEvaluator::VisitRequiresExpr(const RequiresExpr *E) { 12898 return Success(E->isSatisfied(), E); 12899 } 12900 12901 bool FixedPointExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) { 12902 switch (E->getOpcode()) { 12903 default: 12904 // Invalid unary operators 12905 return Error(E); 12906 case UO_Plus: 12907 // The result is just the value. 12908 return Visit(E->getSubExpr()); 12909 case UO_Minus: { 12910 if (!Visit(E->getSubExpr())) return false; 12911 if (!Result.isFixedPoint()) 12912 return Error(E); 12913 bool Overflowed; 12914 APFixedPoint Negated = Result.getFixedPoint().negate(&Overflowed); 12915 if (Overflowed && !HandleOverflow(Info, E, Negated, E->getType())) 12916 return false; 12917 return Success(Negated, E); 12918 } 12919 case UO_LNot: { 12920 bool bres; 12921 if (!EvaluateAsBooleanCondition(E->getSubExpr(), bres, Info)) 12922 return false; 12923 return Success(!bres, E); 12924 } 12925 } 12926 } 12927 12928 bool FixedPointExprEvaluator::VisitCastExpr(const CastExpr *E) { 12929 const Expr *SubExpr = E->getSubExpr(); 12930 QualType DestType = E->getType(); 12931 assert(DestType->isFixedPointType() && 12932 "Expected destination type to be a fixed point type"); 12933 auto DestFXSema = Info.Ctx.getFixedPointSemantics(DestType); 12934 12935 switch (E->getCastKind()) { 12936 case CK_FixedPointCast: { 12937 APFixedPoint Src(Info.Ctx.getFixedPointSemantics(SubExpr->getType())); 12938 if (!EvaluateFixedPoint(SubExpr, Src, Info)) 12939 return false; 12940 bool Overflowed; 12941 APFixedPoint Result = Src.convert(DestFXSema, &Overflowed); 12942 if (Overflowed) { 12943 if (Info.checkingForUndefinedBehavior()) 12944 Info.Ctx.getDiagnostics().Report(E->getExprLoc(), 12945 diag::warn_fixedpoint_constant_overflow) 12946 << Result.toString() << E->getType(); 12947 else if (!HandleOverflow(Info, E, Result, E->getType())) 12948 return false; 12949 } 12950 return Success(Result, E); 12951 } 12952 case CK_IntegralToFixedPoint: { 12953 APSInt Src; 12954 if (!EvaluateInteger(SubExpr, Src, Info)) 12955 return false; 12956 12957 bool Overflowed; 12958 APFixedPoint IntResult = APFixedPoint::getFromIntValue( 12959 Src, Info.Ctx.getFixedPointSemantics(DestType), &Overflowed); 12960 12961 if (Overflowed) { 12962 if (Info.checkingForUndefinedBehavior()) 12963 Info.Ctx.getDiagnostics().Report(E->getExprLoc(), 12964 diag::warn_fixedpoint_constant_overflow) 12965 << IntResult.toString() << E->getType(); 12966 else if (!HandleOverflow(Info, E, IntResult, E->getType())) 12967 return false; 12968 } 12969 12970 return Success(IntResult, E); 12971 } 12972 case CK_NoOp: 12973 case CK_LValueToRValue: 12974 return ExprEvaluatorBaseTy::VisitCastExpr(E); 12975 default: 12976 return Error(E); 12977 } 12978 } 12979 12980 bool FixedPointExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { 12981 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma) 12982 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 12983 12984 const Expr *LHS = E->getLHS(); 12985 const Expr *RHS = E->getRHS(); 12986 FixedPointSemantics ResultFXSema = 12987 Info.Ctx.getFixedPointSemantics(E->getType()); 12988 12989 APFixedPoint LHSFX(Info.Ctx.getFixedPointSemantics(LHS->getType())); 12990 if (!EvaluateFixedPointOrInteger(LHS, LHSFX, Info)) 12991 return false; 12992 APFixedPoint RHSFX(Info.Ctx.getFixedPointSemantics(RHS->getType())); 12993 if (!EvaluateFixedPointOrInteger(RHS, RHSFX, Info)) 12994 return false; 12995 12996 bool OpOverflow = false, ConversionOverflow = false; 12997 APFixedPoint Result(LHSFX.getSemantics()); 12998 switch (E->getOpcode()) { 12999 case BO_Add: { 13000 Result = LHSFX.add(RHSFX, &OpOverflow) 13001 .convert(ResultFXSema, &ConversionOverflow); 13002 break; 13003 } 13004 case BO_Sub: { 13005 Result = LHSFX.sub(RHSFX, &OpOverflow) 13006 .convert(ResultFXSema, &ConversionOverflow); 13007 break; 13008 } 13009 case BO_Mul: { 13010 Result = LHSFX.mul(RHSFX, &OpOverflow) 13011 .convert(ResultFXSema, &ConversionOverflow); 13012 break; 13013 } 13014 case BO_Div: { 13015 if (RHSFX.getValue() == 0) { 13016 Info.FFDiag(E, diag::note_expr_divide_by_zero); 13017 return false; 13018 } 13019 Result = LHSFX.div(RHSFX, &OpOverflow) 13020 .convert(ResultFXSema, &ConversionOverflow); 13021 break; 13022 } 13023 default: 13024 return false; 13025 } 13026 if (OpOverflow || ConversionOverflow) { 13027 if (Info.checkingForUndefinedBehavior()) 13028 Info.Ctx.getDiagnostics().Report(E->getExprLoc(), 13029 diag::warn_fixedpoint_constant_overflow) 13030 << Result.toString() << E->getType(); 13031 else if (!HandleOverflow(Info, E, Result, E->getType())) 13032 return false; 13033 } 13034 return Success(Result, E); 13035 } 13036 13037 //===----------------------------------------------------------------------===// 13038 // Float Evaluation 13039 //===----------------------------------------------------------------------===// 13040 13041 namespace { 13042 class FloatExprEvaluator 13043 : public ExprEvaluatorBase<FloatExprEvaluator> { 13044 APFloat &Result; 13045 public: 13046 FloatExprEvaluator(EvalInfo &info, APFloat &result) 13047 : ExprEvaluatorBaseTy(info), Result(result) {} 13048 13049 bool Success(const APValue &V, const Expr *e) { 13050 Result = V.getFloat(); 13051 return true; 13052 } 13053 13054 bool ZeroInitialization(const Expr *E) { 13055 Result = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(E->getType())); 13056 return true; 13057 } 13058 13059 bool VisitCallExpr(const CallExpr *E); 13060 13061 bool VisitUnaryOperator(const UnaryOperator *E); 13062 bool VisitBinaryOperator(const BinaryOperator *E); 13063 bool VisitFloatingLiteral(const FloatingLiteral *E); 13064 bool VisitCastExpr(const CastExpr *E); 13065 13066 bool VisitUnaryReal(const UnaryOperator *E); 13067 bool VisitUnaryImag(const UnaryOperator *E); 13068 13069 // FIXME: Missing: array subscript of vector, member of vector 13070 }; 13071 } // end anonymous namespace 13072 13073 static bool EvaluateFloat(const Expr* E, APFloat& Result, EvalInfo &Info) { 13074 assert(E->isRValue() && E->getType()->isRealFloatingType()); 13075 return FloatExprEvaluator(Info, Result).Visit(E); 13076 } 13077 13078 static bool TryEvaluateBuiltinNaN(const ASTContext &Context, 13079 QualType ResultTy, 13080 const Expr *Arg, 13081 bool SNaN, 13082 llvm::APFloat &Result) { 13083 const StringLiteral *S = dyn_cast<StringLiteral>(Arg->IgnoreParenCasts()); 13084 if (!S) return false; 13085 13086 const llvm::fltSemantics &Sem = Context.getFloatTypeSemantics(ResultTy); 13087 13088 llvm::APInt fill; 13089 13090 // Treat empty strings as if they were zero. 13091 if (S->getString().empty()) 13092 fill = llvm::APInt(32, 0); 13093 else if (S->getString().getAsInteger(0, fill)) 13094 return false; 13095 13096 if (Context.getTargetInfo().isNan2008()) { 13097 if (SNaN) 13098 Result = llvm::APFloat::getSNaN(Sem, false, &fill); 13099 else 13100 Result = llvm::APFloat::getQNaN(Sem, false, &fill); 13101 } else { 13102 // Prior to IEEE 754-2008, architectures were allowed to choose whether 13103 // the first bit of their significand was set for qNaN or sNaN. MIPS chose 13104 // a different encoding to what became a standard in 2008, and for pre- 13105 // 2008 revisions, MIPS interpreted sNaN-2008 as qNan and qNaN-2008 as 13106 // sNaN. This is now known as "legacy NaN" encoding. 13107 if (SNaN) 13108 Result = llvm::APFloat::getQNaN(Sem, false, &fill); 13109 else 13110 Result = llvm::APFloat::getSNaN(Sem, false, &fill); 13111 } 13112 13113 return true; 13114 } 13115 13116 bool FloatExprEvaluator::VisitCallExpr(const CallExpr *E) { 13117 switch (E->getBuiltinCallee()) { 13118 default: 13119 return ExprEvaluatorBaseTy::VisitCallExpr(E); 13120 13121 case Builtin::BI__builtin_huge_val: 13122 case Builtin::BI__builtin_huge_valf: 13123 case Builtin::BI__builtin_huge_vall: 13124 case Builtin::BI__builtin_huge_valf128: 13125 case Builtin::BI__builtin_inf: 13126 case Builtin::BI__builtin_inff: 13127 case Builtin::BI__builtin_infl: 13128 case Builtin::BI__builtin_inff128: { 13129 const llvm::fltSemantics &Sem = 13130 Info.Ctx.getFloatTypeSemantics(E->getType()); 13131 Result = llvm::APFloat::getInf(Sem); 13132 return true; 13133 } 13134 13135 case Builtin::BI__builtin_nans: 13136 case Builtin::BI__builtin_nansf: 13137 case Builtin::BI__builtin_nansl: 13138 case Builtin::BI__builtin_nansf128: 13139 if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0), 13140 true, Result)) 13141 return Error(E); 13142 return true; 13143 13144 case Builtin::BI__builtin_nan: 13145 case Builtin::BI__builtin_nanf: 13146 case Builtin::BI__builtin_nanl: 13147 case Builtin::BI__builtin_nanf128: 13148 // If this is __builtin_nan() turn this into a nan, otherwise we 13149 // can't constant fold it. 13150 if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0), 13151 false, Result)) 13152 return Error(E); 13153 return true; 13154 13155 case Builtin::BI__builtin_fabs: 13156 case Builtin::BI__builtin_fabsf: 13157 case Builtin::BI__builtin_fabsl: 13158 case Builtin::BI__builtin_fabsf128: 13159 if (!EvaluateFloat(E->getArg(0), Result, Info)) 13160 return false; 13161 13162 if (Result.isNegative()) 13163 Result.changeSign(); 13164 return true; 13165 13166 // FIXME: Builtin::BI__builtin_powi 13167 // FIXME: Builtin::BI__builtin_powif 13168 // FIXME: Builtin::BI__builtin_powil 13169 13170 case Builtin::BI__builtin_copysign: 13171 case Builtin::BI__builtin_copysignf: 13172 case Builtin::BI__builtin_copysignl: 13173 case Builtin::BI__builtin_copysignf128: { 13174 APFloat RHS(0.); 13175 if (!EvaluateFloat(E->getArg(0), Result, Info) || 13176 !EvaluateFloat(E->getArg(1), RHS, Info)) 13177 return false; 13178 Result.copySign(RHS); 13179 return true; 13180 } 13181 } 13182 } 13183 13184 bool FloatExprEvaluator::VisitUnaryReal(const UnaryOperator *E) { 13185 if (E->getSubExpr()->getType()->isAnyComplexType()) { 13186 ComplexValue CV; 13187 if (!EvaluateComplex(E->getSubExpr(), CV, Info)) 13188 return false; 13189 Result = CV.FloatReal; 13190 return true; 13191 } 13192 13193 return Visit(E->getSubExpr()); 13194 } 13195 13196 bool FloatExprEvaluator::VisitUnaryImag(const UnaryOperator *E) { 13197 if (E->getSubExpr()->getType()->isAnyComplexType()) { 13198 ComplexValue CV; 13199 if (!EvaluateComplex(E->getSubExpr(), CV, Info)) 13200 return false; 13201 Result = CV.FloatImag; 13202 return true; 13203 } 13204 13205 VisitIgnoredValue(E->getSubExpr()); 13206 const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(E->getType()); 13207 Result = llvm::APFloat::getZero(Sem); 13208 return true; 13209 } 13210 13211 bool FloatExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) { 13212 switch (E->getOpcode()) { 13213 default: return Error(E); 13214 case UO_Plus: 13215 return EvaluateFloat(E->getSubExpr(), Result, Info); 13216 case UO_Minus: 13217 if (!EvaluateFloat(E->getSubExpr(), Result, Info)) 13218 return false; 13219 Result.changeSign(); 13220 return true; 13221 } 13222 } 13223 13224 bool FloatExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { 13225 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma) 13226 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 13227 13228 APFloat RHS(0.0); 13229 bool LHSOK = EvaluateFloat(E->getLHS(), Result, Info); 13230 if (!LHSOK && !Info.noteFailure()) 13231 return false; 13232 return EvaluateFloat(E->getRHS(), RHS, Info) && LHSOK && 13233 handleFloatFloatBinOp(Info, E, Result, E->getOpcode(), RHS); 13234 } 13235 13236 bool FloatExprEvaluator::VisitFloatingLiteral(const FloatingLiteral *E) { 13237 Result = E->getValue(); 13238 return true; 13239 } 13240 13241 bool FloatExprEvaluator::VisitCastExpr(const CastExpr *E) { 13242 const Expr* SubExpr = E->getSubExpr(); 13243 13244 switch (E->getCastKind()) { 13245 default: 13246 return ExprEvaluatorBaseTy::VisitCastExpr(E); 13247 13248 case CK_IntegralToFloating: { 13249 APSInt IntResult; 13250 return EvaluateInteger(SubExpr, IntResult, Info) && 13251 HandleIntToFloatCast(Info, E, SubExpr->getType(), IntResult, 13252 E->getType(), Result); 13253 } 13254 13255 case CK_FloatingCast: { 13256 if (!Visit(SubExpr)) 13257 return false; 13258 return HandleFloatToFloatCast(Info, E, SubExpr->getType(), E->getType(), 13259 Result); 13260 } 13261 13262 case CK_FloatingComplexToReal: { 13263 ComplexValue V; 13264 if (!EvaluateComplex(SubExpr, V, Info)) 13265 return false; 13266 Result = V.getComplexFloatReal(); 13267 return true; 13268 } 13269 } 13270 } 13271 13272 //===----------------------------------------------------------------------===// 13273 // Complex Evaluation (for float and integer) 13274 //===----------------------------------------------------------------------===// 13275 13276 namespace { 13277 class ComplexExprEvaluator 13278 : public ExprEvaluatorBase<ComplexExprEvaluator> { 13279 ComplexValue &Result; 13280 13281 public: 13282 ComplexExprEvaluator(EvalInfo &info, ComplexValue &Result) 13283 : ExprEvaluatorBaseTy(info), Result(Result) {} 13284 13285 bool Success(const APValue &V, const Expr *e) { 13286 Result.setFrom(V); 13287 return true; 13288 } 13289 13290 bool ZeroInitialization(const Expr *E); 13291 13292 //===--------------------------------------------------------------------===// 13293 // Visitor Methods 13294 //===--------------------------------------------------------------------===// 13295 13296 bool VisitImaginaryLiteral(const ImaginaryLiteral *E); 13297 bool VisitCastExpr(const CastExpr *E); 13298 bool VisitBinaryOperator(const BinaryOperator *E); 13299 bool VisitUnaryOperator(const UnaryOperator *E); 13300 bool VisitInitListExpr(const InitListExpr *E); 13301 }; 13302 } // end anonymous namespace 13303 13304 static bool EvaluateComplex(const Expr *E, ComplexValue &Result, 13305 EvalInfo &Info) { 13306 assert(E->isRValue() && E->getType()->isAnyComplexType()); 13307 return ComplexExprEvaluator(Info, Result).Visit(E); 13308 } 13309 13310 bool ComplexExprEvaluator::ZeroInitialization(const Expr *E) { 13311 QualType ElemTy = E->getType()->castAs<ComplexType>()->getElementType(); 13312 if (ElemTy->isRealFloatingType()) { 13313 Result.makeComplexFloat(); 13314 APFloat Zero = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(ElemTy)); 13315 Result.FloatReal = Zero; 13316 Result.FloatImag = Zero; 13317 } else { 13318 Result.makeComplexInt(); 13319 APSInt Zero = Info.Ctx.MakeIntValue(0, ElemTy); 13320 Result.IntReal = Zero; 13321 Result.IntImag = Zero; 13322 } 13323 return true; 13324 } 13325 13326 bool ComplexExprEvaluator::VisitImaginaryLiteral(const ImaginaryLiteral *E) { 13327 const Expr* SubExpr = E->getSubExpr(); 13328 13329 if (SubExpr->getType()->isRealFloatingType()) { 13330 Result.makeComplexFloat(); 13331 APFloat &Imag = Result.FloatImag; 13332 if (!EvaluateFloat(SubExpr, Imag, Info)) 13333 return false; 13334 13335 Result.FloatReal = APFloat(Imag.getSemantics()); 13336 return true; 13337 } else { 13338 assert(SubExpr->getType()->isIntegerType() && 13339 "Unexpected imaginary literal."); 13340 13341 Result.makeComplexInt(); 13342 APSInt &Imag = Result.IntImag; 13343 if (!EvaluateInteger(SubExpr, Imag, Info)) 13344 return false; 13345 13346 Result.IntReal = APSInt(Imag.getBitWidth(), !Imag.isSigned()); 13347 return true; 13348 } 13349 } 13350 13351 bool ComplexExprEvaluator::VisitCastExpr(const CastExpr *E) { 13352 13353 switch (E->getCastKind()) { 13354 case CK_BitCast: 13355 case CK_BaseToDerived: 13356 case CK_DerivedToBase: 13357 case CK_UncheckedDerivedToBase: 13358 case CK_Dynamic: 13359 case CK_ToUnion: 13360 case CK_ArrayToPointerDecay: 13361 case CK_FunctionToPointerDecay: 13362 case CK_NullToPointer: 13363 case CK_NullToMemberPointer: 13364 case CK_BaseToDerivedMemberPointer: 13365 case CK_DerivedToBaseMemberPointer: 13366 case CK_MemberPointerToBoolean: 13367 case CK_ReinterpretMemberPointer: 13368 case CK_ConstructorConversion: 13369 case CK_IntegralToPointer: 13370 case CK_PointerToIntegral: 13371 case CK_PointerToBoolean: 13372 case CK_ToVoid: 13373 case CK_VectorSplat: 13374 case CK_IntegralCast: 13375 case CK_BooleanToSignedIntegral: 13376 case CK_IntegralToBoolean: 13377 case CK_IntegralToFloating: 13378 case CK_FloatingToIntegral: 13379 case CK_FloatingToBoolean: 13380 case CK_FloatingCast: 13381 case CK_CPointerToObjCPointerCast: 13382 case CK_BlockPointerToObjCPointerCast: 13383 case CK_AnyPointerToBlockPointerCast: 13384 case CK_ObjCObjectLValueCast: 13385 case CK_FloatingComplexToReal: 13386 case CK_FloatingComplexToBoolean: 13387 case CK_IntegralComplexToReal: 13388 case CK_IntegralComplexToBoolean: 13389 case CK_ARCProduceObject: 13390 case CK_ARCConsumeObject: 13391 case CK_ARCReclaimReturnedObject: 13392 case CK_ARCExtendBlockObject: 13393 case CK_CopyAndAutoreleaseBlockObject: 13394 case CK_BuiltinFnToFnPtr: 13395 case CK_ZeroToOCLOpaqueType: 13396 case CK_NonAtomicToAtomic: 13397 case CK_AddressSpaceConversion: 13398 case CK_IntToOCLSampler: 13399 case CK_FixedPointCast: 13400 case CK_FixedPointToBoolean: 13401 case CK_FixedPointToIntegral: 13402 case CK_IntegralToFixedPoint: 13403 llvm_unreachable("invalid cast kind for complex value"); 13404 13405 case CK_LValueToRValue: 13406 case CK_AtomicToNonAtomic: 13407 case CK_NoOp: 13408 case CK_LValueToRValueBitCast: 13409 return ExprEvaluatorBaseTy::VisitCastExpr(E); 13410 13411 case CK_Dependent: 13412 case CK_LValueBitCast: 13413 case CK_UserDefinedConversion: 13414 return Error(E); 13415 13416 case CK_FloatingRealToComplex: { 13417 APFloat &Real = Result.FloatReal; 13418 if (!EvaluateFloat(E->getSubExpr(), Real, Info)) 13419 return false; 13420 13421 Result.makeComplexFloat(); 13422 Result.FloatImag = APFloat(Real.getSemantics()); 13423 return true; 13424 } 13425 13426 case CK_FloatingComplexCast: { 13427 if (!Visit(E->getSubExpr())) 13428 return false; 13429 13430 QualType To = E->getType()->castAs<ComplexType>()->getElementType(); 13431 QualType From 13432 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType(); 13433 13434 return HandleFloatToFloatCast(Info, E, From, To, Result.FloatReal) && 13435 HandleFloatToFloatCast(Info, E, From, To, Result.FloatImag); 13436 } 13437 13438 case CK_FloatingComplexToIntegralComplex: { 13439 if (!Visit(E->getSubExpr())) 13440 return false; 13441 13442 QualType To = E->getType()->castAs<ComplexType>()->getElementType(); 13443 QualType From 13444 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType(); 13445 Result.makeComplexInt(); 13446 return HandleFloatToIntCast(Info, E, From, Result.FloatReal, 13447 To, Result.IntReal) && 13448 HandleFloatToIntCast(Info, E, From, Result.FloatImag, 13449 To, Result.IntImag); 13450 } 13451 13452 case CK_IntegralRealToComplex: { 13453 APSInt &Real = Result.IntReal; 13454 if (!EvaluateInteger(E->getSubExpr(), Real, Info)) 13455 return false; 13456 13457 Result.makeComplexInt(); 13458 Result.IntImag = APSInt(Real.getBitWidth(), !Real.isSigned()); 13459 return true; 13460 } 13461 13462 case CK_IntegralComplexCast: { 13463 if (!Visit(E->getSubExpr())) 13464 return false; 13465 13466 QualType To = E->getType()->castAs<ComplexType>()->getElementType(); 13467 QualType From 13468 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType(); 13469 13470 Result.IntReal = HandleIntToIntCast(Info, E, To, From, Result.IntReal); 13471 Result.IntImag = HandleIntToIntCast(Info, E, To, From, Result.IntImag); 13472 return true; 13473 } 13474 13475 case CK_IntegralComplexToFloatingComplex: { 13476 if (!Visit(E->getSubExpr())) 13477 return false; 13478 13479 QualType To = E->getType()->castAs<ComplexType>()->getElementType(); 13480 QualType From 13481 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType(); 13482 Result.makeComplexFloat(); 13483 return HandleIntToFloatCast(Info, E, From, Result.IntReal, 13484 To, Result.FloatReal) && 13485 HandleIntToFloatCast(Info, E, From, Result.IntImag, 13486 To, Result.FloatImag); 13487 } 13488 } 13489 13490 llvm_unreachable("unknown cast resulting in complex value"); 13491 } 13492 13493 bool ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { 13494 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma) 13495 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 13496 13497 // Track whether the LHS or RHS is real at the type system level. When this is 13498 // the case we can simplify our evaluation strategy. 13499 bool LHSReal = false, RHSReal = false; 13500 13501 bool LHSOK; 13502 if (E->getLHS()->getType()->isRealFloatingType()) { 13503 LHSReal = true; 13504 APFloat &Real = Result.FloatReal; 13505 LHSOK = EvaluateFloat(E->getLHS(), Real, Info); 13506 if (LHSOK) { 13507 Result.makeComplexFloat(); 13508 Result.FloatImag = APFloat(Real.getSemantics()); 13509 } 13510 } else { 13511 LHSOK = Visit(E->getLHS()); 13512 } 13513 if (!LHSOK && !Info.noteFailure()) 13514 return false; 13515 13516 ComplexValue RHS; 13517 if (E->getRHS()->getType()->isRealFloatingType()) { 13518 RHSReal = true; 13519 APFloat &Real = RHS.FloatReal; 13520 if (!EvaluateFloat(E->getRHS(), Real, Info) || !LHSOK) 13521 return false; 13522 RHS.makeComplexFloat(); 13523 RHS.FloatImag = APFloat(Real.getSemantics()); 13524 } else if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK) 13525 return false; 13526 13527 assert(!(LHSReal && RHSReal) && 13528 "Cannot have both operands of a complex operation be real."); 13529 switch (E->getOpcode()) { 13530 default: return Error(E); 13531 case BO_Add: 13532 if (Result.isComplexFloat()) { 13533 Result.getComplexFloatReal().add(RHS.getComplexFloatReal(), 13534 APFloat::rmNearestTiesToEven); 13535 if (LHSReal) 13536 Result.getComplexFloatImag() = RHS.getComplexFloatImag(); 13537 else if (!RHSReal) 13538 Result.getComplexFloatImag().add(RHS.getComplexFloatImag(), 13539 APFloat::rmNearestTiesToEven); 13540 } else { 13541 Result.getComplexIntReal() += RHS.getComplexIntReal(); 13542 Result.getComplexIntImag() += RHS.getComplexIntImag(); 13543 } 13544 break; 13545 case BO_Sub: 13546 if (Result.isComplexFloat()) { 13547 Result.getComplexFloatReal().subtract(RHS.getComplexFloatReal(), 13548 APFloat::rmNearestTiesToEven); 13549 if (LHSReal) { 13550 Result.getComplexFloatImag() = RHS.getComplexFloatImag(); 13551 Result.getComplexFloatImag().changeSign(); 13552 } else if (!RHSReal) { 13553 Result.getComplexFloatImag().subtract(RHS.getComplexFloatImag(), 13554 APFloat::rmNearestTiesToEven); 13555 } 13556 } else { 13557 Result.getComplexIntReal() -= RHS.getComplexIntReal(); 13558 Result.getComplexIntImag() -= RHS.getComplexIntImag(); 13559 } 13560 break; 13561 case BO_Mul: 13562 if (Result.isComplexFloat()) { 13563 // This is an implementation of complex multiplication according to the 13564 // constraints laid out in C11 Annex G. The implementation uses the 13565 // following naming scheme: 13566 // (a + ib) * (c + id) 13567 ComplexValue LHS = Result; 13568 APFloat &A = LHS.getComplexFloatReal(); 13569 APFloat &B = LHS.getComplexFloatImag(); 13570 APFloat &C = RHS.getComplexFloatReal(); 13571 APFloat &D = RHS.getComplexFloatImag(); 13572 APFloat &ResR = Result.getComplexFloatReal(); 13573 APFloat &ResI = Result.getComplexFloatImag(); 13574 if (LHSReal) { 13575 assert(!RHSReal && "Cannot have two real operands for a complex op!"); 13576 ResR = A * C; 13577 ResI = A * D; 13578 } else if (RHSReal) { 13579 ResR = C * A; 13580 ResI = C * B; 13581 } else { 13582 // In the fully general case, we need to handle NaNs and infinities 13583 // robustly. 13584 APFloat AC = A * C; 13585 APFloat BD = B * D; 13586 APFloat AD = A * D; 13587 APFloat BC = B * C; 13588 ResR = AC - BD; 13589 ResI = AD + BC; 13590 if (ResR.isNaN() && ResI.isNaN()) { 13591 bool Recalc = false; 13592 if (A.isInfinity() || B.isInfinity()) { 13593 A = APFloat::copySign( 13594 APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), A); 13595 B = APFloat::copySign( 13596 APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), B); 13597 if (C.isNaN()) 13598 C = APFloat::copySign(APFloat(C.getSemantics()), C); 13599 if (D.isNaN()) 13600 D = APFloat::copySign(APFloat(D.getSemantics()), D); 13601 Recalc = true; 13602 } 13603 if (C.isInfinity() || D.isInfinity()) { 13604 C = APFloat::copySign( 13605 APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), C); 13606 D = APFloat::copySign( 13607 APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), D); 13608 if (A.isNaN()) 13609 A = APFloat::copySign(APFloat(A.getSemantics()), A); 13610 if (B.isNaN()) 13611 B = APFloat::copySign(APFloat(B.getSemantics()), B); 13612 Recalc = true; 13613 } 13614 if (!Recalc && (AC.isInfinity() || BD.isInfinity() || 13615 AD.isInfinity() || BC.isInfinity())) { 13616 if (A.isNaN()) 13617 A = APFloat::copySign(APFloat(A.getSemantics()), A); 13618 if (B.isNaN()) 13619 B = APFloat::copySign(APFloat(B.getSemantics()), B); 13620 if (C.isNaN()) 13621 C = APFloat::copySign(APFloat(C.getSemantics()), C); 13622 if (D.isNaN()) 13623 D = APFloat::copySign(APFloat(D.getSemantics()), D); 13624 Recalc = true; 13625 } 13626 if (Recalc) { 13627 ResR = APFloat::getInf(A.getSemantics()) * (A * C - B * D); 13628 ResI = APFloat::getInf(A.getSemantics()) * (A * D + B * C); 13629 } 13630 } 13631 } 13632 } else { 13633 ComplexValue LHS = Result; 13634 Result.getComplexIntReal() = 13635 (LHS.getComplexIntReal() * RHS.getComplexIntReal() - 13636 LHS.getComplexIntImag() * RHS.getComplexIntImag()); 13637 Result.getComplexIntImag() = 13638 (LHS.getComplexIntReal() * RHS.getComplexIntImag() + 13639 LHS.getComplexIntImag() * RHS.getComplexIntReal()); 13640 } 13641 break; 13642 case BO_Div: 13643 if (Result.isComplexFloat()) { 13644 // This is an implementation of complex division according to the 13645 // constraints laid out in C11 Annex G. The implementation uses the 13646 // following naming scheme: 13647 // (a + ib) / (c + id) 13648 ComplexValue LHS = Result; 13649 APFloat &A = LHS.getComplexFloatReal(); 13650 APFloat &B = LHS.getComplexFloatImag(); 13651 APFloat &C = RHS.getComplexFloatReal(); 13652 APFloat &D = RHS.getComplexFloatImag(); 13653 APFloat &ResR = Result.getComplexFloatReal(); 13654 APFloat &ResI = Result.getComplexFloatImag(); 13655 if (RHSReal) { 13656 ResR = A / C; 13657 ResI = B / C; 13658 } else { 13659 if (LHSReal) { 13660 // No real optimizations we can do here, stub out with zero. 13661 B = APFloat::getZero(A.getSemantics()); 13662 } 13663 int DenomLogB = 0; 13664 APFloat MaxCD = maxnum(abs(C), abs(D)); 13665 if (MaxCD.isFinite()) { 13666 DenomLogB = ilogb(MaxCD); 13667 C = scalbn(C, -DenomLogB, APFloat::rmNearestTiesToEven); 13668 D = scalbn(D, -DenomLogB, APFloat::rmNearestTiesToEven); 13669 } 13670 APFloat Denom = C * C + D * D; 13671 ResR = scalbn((A * C + B * D) / Denom, -DenomLogB, 13672 APFloat::rmNearestTiesToEven); 13673 ResI = scalbn((B * C - A * D) / Denom, -DenomLogB, 13674 APFloat::rmNearestTiesToEven); 13675 if (ResR.isNaN() && ResI.isNaN()) { 13676 if (Denom.isPosZero() && (!A.isNaN() || !B.isNaN())) { 13677 ResR = APFloat::getInf(ResR.getSemantics(), C.isNegative()) * A; 13678 ResI = APFloat::getInf(ResR.getSemantics(), C.isNegative()) * B; 13679 } else if ((A.isInfinity() || B.isInfinity()) && C.isFinite() && 13680 D.isFinite()) { 13681 A = APFloat::copySign( 13682 APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), A); 13683 B = APFloat::copySign( 13684 APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), B); 13685 ResR = APFloat::getInf(ResR.getSemantics()) * (A * C + B * D); 13686 ResI = APFloat::getInf(ResI.getSemantics()) * (B * C - A * D); 13687 } else if (MaxCD.isInfinity() && A.isFinite() && B.isFinite()) { 13688 C = APFloat::copySign( 13689 APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), C); 13690 D = APFloat::copySign( 13691 APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), D); 13692 ResR = APFloat::getZero(ResR.getSemantics()) * (A * C + B * D); 13693 ResI = APFloat::getZero(ResI.getSemantics()) * (B * C - A * D); 13694 } 13695 } 13696 } 13697 } else { 13698 if (RHS.getComplexIntReal() == 0 && RHS.getComplexIntImag() == 0) 13699 return Error(E, diag::note_expr_divide_by_zero); 13700 13701 ComplexValue LHS = Result; 13702 APSInt Den = RHS.getComplexIntReal() * RHS.getComplexIntReal() + 13703 RHS.getComplexIntImag() * RHS.getComplexIntImag(); 13704 Result.getComplexIntReal() = 13705 (LHS.getComplexIntReal() * RHS.getComplexIntReal() + 13706 LHS.getComplexIntImag() * RHS.getComplexIntImag()) / Den; 13707 Result.getComplexIntImag() = 13708 (LHS.getComplexIntImag() * RHS.getComplexIntReal() - 13709 LHS.getComplexIntReal() * RHS.getComplexIntImag()) / Den; 13710 } 13711 break; 13712 } 13713 13714 return true; 13715 } 13716 13717 bool ComplexExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) { 13718 // Get the operand value into 'Result'. 13719 if (!Visit(E->getSubExpr())) 13720 return false; 13721 13722 switch (E->getOpcode()) { 13723 default: 13724 return Error(E); 13725 case UO_Extension: 13726 return true; 13727 case UO_Plus: 13728 // The result is always just the subexpr. 13729 return true; 13730 case UO_Minus: 13731 if (Result.isComplexFloat()) { 13732 Result.getComplexFloatReal().changeSign(); 13733 Result.getComplexFloatImag().changeSign(); 13734 } 13735 else { 13736 Result.getComplexIntReal() = -Result.getComplexIntReal(); 13737 Result.getComplexIntImag() = -Result.getComplexIntImag(); 13738 } 13739 return true; 13740 case UO_Not: 13741 if (Result.isComplexFloat()) 13742 Result.getComplexFloatImag().changeSign(); 13743 else 13744 Result.getComplexIntImag() = -Result.getComplexIntImag(); 13745 return true; 13746 } 13747 } 13748 13749 bool ComplexExprEvaluator::VisitInitListExpr(const InitListExpr *E) { 13750 if (E->getNumInits() == 2) { 13751 if (E->getType()->isComplexType()) { 13752 Result.makeComplexFloat(); 13753 if (!EvaluateFloat(E->getInit(0), Result.FloatReal, Info)) 13754 return false; 13755 if (!EvaluateFloat(E->getInit(1), Result.FloatImag, Info)) 13756 return false; 13757 } else { 13758 Result.makeComplexInt(); 13759 if (!EvaluateInteger(E->getInit(0), Result.IntReal, Info)) 13760 return false; 13761 if (!EvaluateInteger(E->getInit(1), Result.IntImag, Info)) 13762 return false; 13763 } 13764 return true; 13765 } 13766 return ExprEvaluatorBaseTy::VisitInitListExpr(E); 13767 } 13768 13769 //===----------------------------------------------------------------------===// 13770 // Atomic expression evaluation, essentially just handling the NonAtomicToAtomic 13771 // implicit conversion. 13772 //===----------------------------------------------------------------------===// 13773 13774 namespace { 13775 class AtomicExprEvaluator : 13776 public ExprEvaluatorBase<AtomicExprEvaluator> { 13777 const LValue *This; 13778 APValue &Result; 13779 public: 13780 AtomicExprEvaluator(EvalInfo &Info, const LValue *This, APValue &Result) 13781 : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {} 13782 13783 bool Success(const APValue &V, const Expr *E) { 13784 Result = V; 13785 return true; 13786 } 13787 13788 bool ZeroInitialization(const Expr *E) { 13789 ImplicitValueInitExpr VIE( 13790 E->getType()->castAs<AtomicType>()->getValueType()); 13791 // For atomic-qualified class (and array) types in C++, initialize the 13792 // _Atomic-wrapped subobject directly, in-place. 13793 return This ? EvaluateInPlace(Result, Info, *This, &VIE) 13794 : Evaluate(Result, Info, &VIE); 13795 } 13796 13797 bool VisitCastExpr(const CastExpr *E) { 13798 switch (E->getCastKind()) { 13799 default: 13800 return ExprEvaluatorBaseTy::VisitCastExpr(E); 13801 case CK_NonAtomicToAtomic: 13802 return This ? EvaluateInPlace(Result, Info, *This, E->getSubExpr()) 13803 : Evaluate(Result, Info, E->getSubExpr()); 13804 } 13805 } 13806 }; 13807 } // end anonymous namespace 13808 13809 static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result, 13810 EvalInfo &Info) { 13811 assert(E->isRValue() && E->getType()->isAtomicType()); 13812 return AtomicExprEvaluator(Info, This, Result).Visit(E); 13813 } 13814 13815 //===----------------------------------------------------------------------===// 13816 // Void expression evaluation, primarily for a cast to void on the LHS of a 13817 // comma operator 13818 //===----------------------------------------------------------------------===// 13819 13820 namespace { 13821 class VoidExprEvaluator 13822 : public ExprEvaluatorBase<VoidExprEvaluator> { 13823 public: 13824 VoidExprEvaluator(EvalInfo &Info) : ExprEvaluatorBaseTy(Info) {} 13825 13826 bool Success(const APValue &V, const Expr *e) { return true; } 13827 13828 bool ZeroInitialization(const Expr *E) { return true; } 13829 13830 bool VisitCastExpr(const CastExpr *E) { 13831 switch (E->getCastKind()) { 13832 default: 13833 return ExprEvaluatorBaseTy::VisitCastExpr(E); 13834 case CK_ToVoid: 13835 VisitIgnoredValue(E->getSubExpr()); 13836 return true; 13837 } 13838 } 13839 13840 bool VisitCallExpr(const CallExpr *E) { 13841 switch (E->getBuiltinCallee()) { 13842 case Builtin::BI__assume: 13843 case Builtin::BI__builtin_assume: 13844 // The argument is not evaluated! 13845 return true; 13846 13847 case Builtin::BI__builtin_operator_delete: 13848 return HandleOperatorDeleteCall(Info, E); 13849 13850 default: 13851 break; 13852 } 13853 13854 return ExprEvaluatorBaseTy::VisitCallExpr(E); 13855 } 13856 13857 bool VisitCXXDeleteExpr(const CXXDeleteExpr *E); 13858 }; 13859 } // end anonymous namespace 13860 13861 bool VoidExprEvaluator::VisitCXXDeleteExpr(const CXXDeleteExpr *E) { 13862 // We cannot speculatively evaluate a delete expression. 13863 if (Info.SpeculativeEvaluationDepth) 13864 return false; 13865 13866 FunctionDecl *OperatorDelete = E->getOperatorDelete(); 13867 if (!OperatorDelete->isReplaceableGlobalAllocationFunction()) { 13868 Info.FFDiag(E, diag::note_constexpr_new_non_replaceable) 13869 << isa<CXXMethodDecl>(OperatorDelete) << OperatorDelete; 13870 return false; 13871 } 13872 13873 const Expr *Arg = E->getArgument(); 13874 13875 LValue Pointer; 13876 if (!EvaluatePointer(Arg, Pointer, Info)) 13877 return false; 13878 if (Pointer.Designator.Invalid) 13879 return false; 13880 13881 // Deleting a null pointer has no effect. 13882 if (Pointer.isNullPointer()) { 13883 // This is the only case where we need to produce an extension warning: 13884 // the only other way we can succeed is if we find a dynamic allocation, 13885 // and we will have warned when we allocated it in that case. 13886 if (!Info.getLangOpts().CPlusPlus20) 13887 Info.CCEDiag(E, diag::note_constexpr_new); 13888 return true; 13889 } 13890 13891 Optional<DynAlloc *> Alloc = CheckDeleteKind( 13892 Info, E, Pointer, E->isArrayForm() ? DynAlloc::ArrayNew : DynAlloc::New); 13893 if (!Alloc) 13894 return false; 13895 QualType AllocType = Pointer.Base.getDynamicAllocType(); 13896 13897 // For the non-array case, the designator must be empty if the static type 13898 // does not have a virtual destructor. 13899 if (!E->isArrayForm() && Pointer.Designator.Entries.size() != 0 && 13900 !hasVirtualDestructor(Arg->getType()->getPointeeType())) { 13901 Info.FFDiag(E, diag::note_constexpr_delete_base_nonvirt_dtor) 13902 << Arg->getType()->getPointeeType() << AllocType; 13903 return false; 13904 } 13905 13906 // For a class type with a virtual destructor, the selected operator delete 13907 // is the one looked up when building the destructor. 13908 if (!E->isArrayForm() && !E->isGlobalDelete()) { 13909 const FunctionDecl *VirtualDelete = getVirtualOperatorDelete(AllocType); 13910 if (VirtualDelete && 13911 !VirtualDelete->isReplaceableGlobalAllocationFunction()) { 13912 Info.FFDiag(E, diag::note_constexpr_new_non_replaceable) 13913 << isa<CXXMethodDecl>(VirtualDelete) << VirtualDelete; 13914 return false; 13915 } 13916 } 13917 13918 if (!HandleDestruction(Info, E->getExprLoc(), Pointer.getLValueBase(), 13919 (*Alloc)->Value, AllocType)) 13920 return false; 13921 13922 if (!Info.HeapAllocs.erase(Pointer.Base.dyn_cast<DynamicAllocLValue>())) { 13923 // The element was already erased. This means the destructor call also 13924 // deleted the object. 13925 // FIXME: This probably results in undefined behavior before we get this 13926 // far, and should be diagnosed elsewhere first. 13927 Info.FFDiag(E, diag::note_constexpr_double_delete); 13928 return false; 13929 } 13930 13931 return true; 13932 } 13933 13934 static bool EvaluateVoid(const Expr *E, EvalInfo &Info) { 13935 assert(E->isRValue() && E->getType()->isVoidType()); 13936 return VoidExprEvaluator(Info).Visit(E); 13937 } 13938 13939 //===----------------------------------------------------------------------===// 13940 // Top level Expr::EvaluateAsRValue method. 13941 //===----------------------------------------------------------------------===// 13942 13943 static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E) { 13944 // In C, function designators are not lvalues, but we evaluate them as if they 13945 // are. 13946 QualType T = E->getType(); 13947 if (E->isGLValue() || T->isFunctionType()) { 13948 LValue LV; 13949 if (!EvaluateLValue(E, LV, Info)) 13950 return false; 13951 LV.moveInto(Result); 13952 } else if (T->isVectorType()) { 13953 if (!EvaluateVector(E, Result, Info)) 13954 return false; 13955 } else if (T->isIntegralOrEnumerationType()) { 13956 if (!IntExprEvaluator(Info, Result).Visit(E)) 13957 return false; 13958 } else if (T->hasPointerRepresentation()) { 13959 LValue LV; 13960 if (!EvaluatePointer(E, LV, Info)) 13961 return false; 13962 LV.moveInto(Result); 13963 } else if (T->isRealFloatingType()) { 13964 llvm::APFloat F(0.0); 13965 if (!EvaluateFloat(E, F, Info)) 13966 return false; 13967 Result = APValue(F); 13968 } else if (T->isAnyComplexType()) { 13969 ComplexValue C; 13970 if (!EvaluateComplex(E, C, Info)) 13971 return false; 13972 C.moveInto(Result); 13973 } else if (T->isFixedPointType()) { 13974 if (!FixedPointExprEvaluator(Info, Result).Visit(E)) return false; 13975 } else if (T->isMemberPointerType()) { 13976 MemberPtr P; 13977 if (!EvaluateMemberPointer(E, P, Info)) 13978 return false; 13979 P.moveInto(Result); 13980 return true; 13981 } else if (T->isArrayType()) { 13982 LValue LV; 13983 APValue &Value = 13984 Info.CurrentCall->createTemporary(E, T, false, LV); 13985 if (!EvaluateArray(E, LV, Value, Info)) 13986 return false; 13987 Result = Value; 13988 } else if (T->isRecordType()) { 13989 LValue LV; 13990 APValue &Value = Info.CurrentCall->createTemporary(E, T, false, LV); 13991 if (!EvaluateRecord(E, LV, Value, Info)) 13992 return false; 13993 Result = Value; 13994 } else if (T->isVoidType()) { 13995 if (!Info.getLangOpts().CPlusPlus11) 13996 Info.CCEDiag(E, diag::note_constexpr_nonliteral) 13997 << E->getType(); 13998 if (!EvaluateVoid(E, Info)) 13999 return false; 14000 } else if (T->isAtomicType()) { 14001 QualType Unqual = T.getAtomicUnqualifiedType(); 14002 if (Unqual->isArrayType() || Unqual->isRecordType()) { 14003 LValue LV; 14004 APValue &Value = Info.CurrentCall->createTemporary(E, Unqual, false, LV); 14005 if (!EvaluateAtomic(E, &LV, Value, Info)) 14006 return false; 14007 } else { 14008 if (!EvaluateAtomic(E, nullptr, Result, Info)) 14009 return false; 14010 } 14011 } else if (Info.getLangOpts().CPlusPlus11) { 14012 Info.FFDiag(E, diag::note_constexpr_nonliteral) << E->getType(); 14013 return false; 14014 } else { 14015 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr); 14016 return false; 14017 } 14018 14019 return true; 14020 } 14021 14022 /// EvaluateInPlace - Evaluate an expression in-place in an APValue. In some 14023 /// cases, the in-place evaluation is essential, since later initializers for 14024 /// an object can indirectly refer to subobjects which were initialized earlier. 14025 static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, const LValue &This, 14026 const Expr *E, bool AllowNonLiteralTypes) { 14027 assert(!E->isValueDependent()); 14028 14029 if (!AllowNonLiteralTypes && !CheckLiteralType(Info, E, &This)) 14030 return false; 14031 14032 if (E->isRValue()) { 14033 // Evaluate arrays and record types in-place, so that later initializers can 14034 // refer to earlier-initialized members of the object. 14035 QualType T = E->getType(); 14036 if (T->isArrayType()) 14037 return EvaluateArray(E, This, Result, Info); 14038 else if (T->isRecordType()) 14039 return EvaluateRecord(E, This, Result, Info); 14040 else if (T->isAtomicType()) { 14041 QualType Unqual = T.getAtomicUnqualifiedType(); 14042 if (Unqual->isArrayType() || Unqual->isRecordType()) 14043 return EvaluateAtomic(E, &This, Result, Info); 14044 } 14045 } 14046 14047 // For any other type, in-place evaluation is unimportant. 14048 return Evaluate(Result, Info, E); 14049 } 14050 14051 /// EvaluateAsRValue - Try to evaluate this expression, performing an implicit 14052 /// lvalue-to-rvalue cast if it is an lvalue. 14053 static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result) { 14054 if (Info.EnableNewConstInterp) { 14055 if (!Info.Ctx.getInterpContext().evaluateAsRValue(Info, E, Result)) 14056 return false; 14057 } else { 14058 if (E->getType().isNull()) 14059 return false; 14060 14061 if (!CheckLiteralType(Info, E)) 14062 return false; 14063 14064 if (!::Evaluate(Result, Info, E)) 14065 return false; 14066 14067 if (E->isGLValue()) { 14068 LValue LV; 14069 LV.setFrom(Info.Ctx, Result); 14070 if (!handleLValueToRValueConversion(Info, E, E->getType(), LV, Result)) 14071 return false; 14072 } 14073 } 14074 14075 // Check this core constant expression is a constant expression. 14076 return CheckConstantExpression(Info, E->getExprLoc(), E->getType(), Result) && 14077 CheckMemoryLeaks(Info); 14078 } 14079 14080 static bool FastEvaluateAsRValue(const Expr *Exp, Expr::EvalResult &Result, 14081 const ASTContext &Ctx, bool &IsConst) { 14082 // Fast-path evaluations of integer literals, since we sometimes see files 14083 // containing vast quantities of these. 14084 if (const IntegerLiteral *L = dyn_cast<IntegerLiteral>(Exp)) { 14085 Result.Val = APValue(APSInt(L->getValue(), 14086 L->getType()->isUnsignedIntegerType())); 14087 IsConst = true; 14088 return true; 14089 } 14090 14091 // This case should be rare, but we need to check it before we check on 14092 // the type below. 14093 if (Exp->getType().isNull()) { 14094 IsConst = false; 14095 return true; 14096 } 14097 14098 // FIXME: Evaluating values of large array and record types can cause 14099 // performance problems. Only do so in C++11 for now. 14100 if (Exp->isRValue() && (Exp->getType()->isArrayType() || 14101 Exp->getType()->isRecordType()) && 14102 !Ctx.getLangOpts().CPlusPlus11) { 14103 IsConst = false; 14104 return true; 14105 } 14106 return false; 14107 } 14108 14109 static bool hasUnacceptableSideEffect(Expr::EvalStatus &Result, 14110 Expr::SideEffectsKind SEK) { 14111 return (SEK < Expr::SE_AllowSideEffects && Result.HasSideEffects) || 14112 (SEK < Expr::SE_AllowUndefinedBehavior && Result.HasUndefinedBehavior); 14113 } 14114 14115 static bool EvaluateAsRValue(const Expr *E, Expr::EvalResult &Result, 14116 const ASTContext &Ctx, EvalInfo &Info) { 14117 bool IsConst; 14118 if (FastEvaluateAsRValue(E, Result, Ctx, IsConst)) 14119 return IsConst; 14120 14121 return EvaluateAsRValue(Info, E, Result.Val); 14122 } 14123 14124 static bool EvaluateAsInt(const Expr *E, Expr::EvalResult &ExprResult, 14125 const ASTContext &Ctx, 14126 Expr::SideEffectsKind AllowSideEffects, 14127 EvalInfo &Info) { 14128 if (!E->getType()->isIntegralOrEnumerationType()) 14129 return false; 14130 14131 if (!::EvaluateAsRValue(E, ExprResult, Ctx, Info) || 14132 !ExprResult.Val.isInt() || 14133 hasUnacceptableSideEffect(ExprResult, AllowSideEffects)) 14134 return false; 14135 14136 return true; 14137 } 14138 14139 static bool EvaluateAsFixedPoint(const Expr *E, Expr::EvalResult &ExprResult, 14140 const ASTContext &Ctx, 14141 Expr::SideEffectsKind AllowSideEffects, 14142 EvalInfo &Info) { 14143 if (!E->getType()->isFixedPointType()) 14144 return false; 14145 14146 if (!::EvaluateAsRValue(E, ExprResult, Ctx, Info)) 14147 return false; 14148 14149 if (!ExprResult.Val.isFixedPoint() || 14150 hasUnacceptableSideEffect(ExprResult, AllowSideEffects)) 14151 return false; 14152 14153 return true; 14154 } 14155 14156 /// EvaluateAsRValue - Return true if this is a constant which we can fold using 14157 /// any crazy technique (that has nothing to do with language standards) that 14158 /// we want to. If this function returns true, it returns the folded constant 14159 /// in Result. If this expression is a glvalue, an lvalue-to-rvalue conversion 14160 /// will be applied to the result. 14161 bool Expr::EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx, 14162 bool InConstantContext) const { 14163 assert(!isValueDependent() && 14164 "Expression evaluator can't be called on a dependent expression."); 14165 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects); 14166 Info.InConstantContext = InConstantContext; 14167 return ::EvaluateAsRValue(this, Result, Ctx, Info); 14168 } 14169 14170 bool Expr::EvaluateAsBooleanCondition(bool &Result, const ASTContext &Ctx, 14171 bool InConstantContext) const { 14172 assert(!isValueDependent() && 14173 "Expression evaluator can't be called on a dependent expression."); 14174 EvalResult Scratch; 14175 return EvaluateAsRValue(Scratch, Ctx, InConstantContext) && 14176 HandleConversionToBool(Scratch.Val, Result); 14177 } 14178 14179 bool Expr::EvaluateAsInt(EvalResult &Result, const ASTContext &Ctx, 14180 SideEffectsKind AllowSideEffects, 14181 bool InConstantContext) const { 14182 assert(!isValueDependent() && 14183 "Expression evaluator can't be called on a dependent expression."); 14184 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects); 14185 Info.InConstantContext = InConstantContext; 14186 return ::EvaluateAsInt(this, Result, Ctx, AllowSideEffects, Info); 14187 } 14188 14189 bool Expr::EvaluateAsFixedPoint(EvalResult &Result, const ASTContext &Ctx, 14190 SideEffectsKind AllowSideEffects, 14191 bool InConstantContext) const { 14192 assert(!isValueDependent() && 14193 "Expression evaluator can't be called on a dependent expression."); 14194 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects); 14195 Info.InConstantContext = InConstantContext; 14196 return ::EvaluateAsFixedPoint(this, Result, Ctx, AllowSideEffects, Info); 14197 } 14198 14199 bool Expr::EvaluateAsFloat(APFloat &Result, const ASTContext &Ctx, 14200 SideEffectsKind AllowSideEffects, 14201 bool InConstantContext) const { 14202 assert(!isValueDependent() && 14203 "Expression evaluator can't be called on a dependent expression."); 14204 14205 if (!getType()->isRealFloatingType()) 14206 return false; 14207 14208 EvalResult ExprResult; 14209 if (!EvaluateAsRValue(ExprResult, Ctx, InConstantContext) || 14210 !ExprResult.Val.isFloat() || 14211 hasUnacceptableSideEffect(ExprResult, AllowSideEffects)) 14212 return false; 14213 14214 Result = ExprResult.Val.getFloat(); 14215 return true; 14216 } 14217 14218 bool Expr::EvaluateAsLValue(EvalResult &Result, const ASTContext &Ctx, 14219 bool InConstantContext) const { 14220 assert(!isValueDependent() && 14221 "Expression evaluator can't be called on a dependent expression."); 14222 14223 EvalInfo Info(Ctx, Result, EvalInfo::EM_ConstantFold); 14224 Info.InConstantContext = InConstantContext; 14225 LValue LV; 14226 CheckedTemporaries CheckedTemps; 14227 if (!EvaluateLValue(this, LV, Info) || !Info.discardCleanups() || 14228 Result.HasSideEffects || 14229 !CheckLValueConstantExpression(Info, getExprLoc(), 14230 Ctx.getLValueReferenceType(getType()), LV, 14231 Expr::EvaluateForCodeGen, CheckedTemps)) 14232 return false; 14233 14234 LV.moveInto(Result.Val); 14235 return true; 14236 } 14237 14238 bool Expr::EvaluateAsConstantExpr(EvalResult &Result, ConstExprUsage Usage, 14239 const ASTContext &Ctx, bool InPlace) const { 14240 assert(!isValueDependent() && 14241 "Expression evaluator can't be called on a dependent expression."); 14242 14243 EvalInfo::EvaluationMode EM = EvalInfo::EM_ConstantExpression; 14244 EvalInfo Info(Ctx, Result, EM); 14245 Info.InConstantContext = true; 14246 14247 if (InPlace) { 14248 Info.setEvaluatingDecl(this, Result.Val); 14249 LValue LVal; 14250 LVal.set(this); 14251 if (!::EvaluateInPlace(Result.Val, Info, LVal, this) || 14252 Result.HasSideEffects) 14253 return false; 14254 } else if (!::Evaluate(Result.Val, Info, this) || Result.HasSideEffects) 14255 return false; 14256 14257 if (!Info.discardCleanups()) 14258 llvm_unreachable("Unhandled cleanup; missing full expression marker?"); 14259 14260 return CheckConstantExpression(Info, getExprLoc(), getStorageType(Ctx, this), 14261 Result.Val, Usage) && 14262 CheckMemoryLeaks(Info); 14263 } 14264 14265 bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx, 14266 const VarDecl *VD, 14267 SmallVectorImpl<PartialDiagnosticAt> &Notes) const { 14268 assert(!isValueDependent() && 14269 "Expression evaluator can't be called on a dependent expression."); 14270 14271 // FIXME: Evaluating initializers for large array and record types can cause 14272 // performance problems. Only do so in C++11 for now. 14273 if (isRValue() && (getType()->isArrayType() || getType()->isRecordType()) && 14274 !Ctx.getLangOpts().CPlusPlus11) 14275 return false; 14276 14277 Expr::EvalStatus EStatus; 14278 EStatus.Diag = &Notes; 14279 14280 EvalInfo Info(Ctx, EStatus, VD->isConstexpr() 14281 ? EvalInfo::EM_ConstantExpression 14282 : EvalInfo::EM_ConstantFold); 14283 Info.setEvaluatingDecl(VD, Value); 14284 Info.InConstantContext = true; 14285 14286 SourceLocation DeclLoc = VD->getLocation(); 14287 QualType DeclTy = VD->getType(); 14288 14289 if (Info.EnableNewConstInterp) { 14290 auto &InterpCtx = const_cast<ASTContext &>(Ctx).getInterpContext(); 14291 if (!InterpCtx.evaluateAsInitializer(Info, VD, Value)) 14292 return false; 14293 } else { 14294 LValue LVal; 14295 LVal.set(VD); 14296 14297 if (!EvaluateInPlace(Value, Info, LVal, this, 14298 /*AllowNonLiteralTypes=*/true) || 14299 EStatus.HasSideEffects) 14300 return false; 14301 14302 // At this point, any lifetime-extended temporaries are completely 14303 // initialized. 14304 Info.performLifetimeExtension(); 14305 14306 if (!Info.discardCleanups()) 14307 llvm_unreachable("Unhandled cleanup; missing full expression marker?"); 14308 } 14309 return CheckConstantExpression(Info, DeclLoc, DeclTy, Value) && 14310 CheckMemoryLeaks(Info); 14311 } 14312 14313 bool VarDecl::evaluateDestruction( 14314 SmallVectorImpl<PartialDiagnosticAt> &Notes) const { 14315 Expr::EvalStatus EStatus; 14316 EStatus.Diag = &Notes; 14317 14318 // Make a copy of the value for the destructor to mutate, if we know it. 14319 // Otherwise, treat the value as default-initialized; if the destructor works 14320 // anyway, then the destruction is constant (and must be essentially empty). 14321 APValue DestroyedValue; 14322 if (getEvaluatedValue() && !getEvaluatedValue()->isAbsent()) 14323 DestroyedValue = *getEvaluatedValue(); 14324 else if (!getDefaultInitValue(getType(), DestroyedValue)) 14325 return false; 14326 14327 EvalInfo Info(getASTContext(), EStatus, EvalInfo::EM_ConstantExpression); 14328 Info.setEvaluatingDecl(this, DestroyedValue, 14329 EvalInfo::EvaluatingDeclKind::Dtor); 14330 Info.InConstantContext = true; 14331 14332 SourceLocation DeclLoc = getLocation(); 14333 QualType DeclTy = getType(); 14334 14335 LValue LVal; 14336 LVal.set(this); 14337 14338 if (!HandleDestruction(Info, DeclLoc, LVal.Base, DestroyedValue, DeclTy) || 14339 EStatus.HasSideEffects) 14340 return false; 14341 14342 if (!Info.discardCleanups()) 14343 llvm_unreachable("Unhandled cleanup; missing full expression marker?"); 14344 14345 ensureEvaluatedStmt()->HasConstantDestruction = true; 14346 return true; 14347 } 14348 14349 /// isEvaluatable - Call EvaluateAsRValue to see if this expression can be 14350 /// constant folded, but discard the result. 14351 bool Expr::isEvaluatable(const ASTContext &Ctx, SideEffectsKind SEK) const { 14352 assert(!isValueDependent() && 14353 "Expression evaluator can't be called on a dependent expression."); 14354 14355 EvalResult Result; 14356 return EvaluateAsRValue(Result, Ctx, /* in constant context */ true) && 14357 !hasUnacceptableSideEffect(Result, SEK); 14358 } 14359 14360 APSInt Expr::EvaluateKnownConstInt(const ASTContext &Ctx, 14361 SmallVectorImpl<PartialDiagnosticAt> *Diag) const { 14362 assert(!isValueDependent() && 14363 "Expression evaluator can't be called on a dependent expression."); 14364 14365 EvalResult EVResult; 14366 EVResult.Diag = Diag; 14367 EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects); 14368 Info.InConstantContext = true; 14369 14370 bool Result = ::EvaluateAsRValue(this, EVResult, Ctx, Info); 14371 (void)Result; 14372 assert(Result && "Could not evaluate expression"); 14373 assert(EVResult.Val.isInt() && "Expression did not evaluate to integer"); 14374 14375 return EVResult.Val.getInt(); 14376 } 14377 14378 APSInt Expr::EvaluateKnownConstIntCheckOverflow( 14379 const ASTContext &Ctx, SmallVectorImpl<PartialDiagnosticAt> *Diag) const { 14380 assert(!isValueDependent() && 14381 "Expression evaluator can't be called on a dependent expression."); 14382 14383 EvalResult EVResult; 14384 EVResult.Diag = Diag; 14385 EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects); 14386 Info.InConstantContext = true; 14387 Info.CheckingForUndefinedBehavior = true; 14388 14389 bool Result = ::EvaluateAsRValue(Info, this, EVResult.Val); 14390 (void)Result; 14391 assert(Result && "Could not evaluate expression"); 14392 assert(EVResult.Val.isInt() && "Expression did not evaluate to integer"); 14393 14394 return EVResult.Val.getInt(); 14395 } 14396 14397 void Expr::EvaluateForOverflow(const ASTContext &Ctx) const { 14398 assert(!isValueDependent() && 14399 "Expression evaluator can't be called on a dependent expression."); 14400 14401 bool IsConst; 14402 EvalResult EVResult; 14403 if (!FastEvaluateAsRValue(this, EVResult, Ctx, IsConst)) { 14404 EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects); 14405 Info.CheckingForUndefinedBehavior = true; 14406 (void)::EvaluateAsRValue(Info, this, EVResult.Val); 14407 } 14408 } 14409 14410 bool Expr::EvalResult::isGlobalLValue() const { 14411 assert(Val.isLValue()); 14412 return IsGlobalLValue(Val.getLValueBase()); 14413 } 14414 14415 14416 /// isIntegerConstantExpr - this recursive routine will test if an expression is 14417 /// an integer constant expression. 14418 14419 /// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero, 14420 /// comma, etc 14421 14422 // CheckICE - This function does the fundamental ICE checking: the returned 14423 // ICEDiag contains an ICEKind indicating whether the expression is an ICE, 14424 // and a (possibly null) SourceLocation indicating the location of the problem. 14425 // 14426 // Note that to reduce code duplication, this helper does no evaluation 14427 // itself; the caller checks whether the expression is evaluatable, and 14428 // in the rare cases where CheckICE actually cares about the evaluated 14429 // value, it calls into Evaluate. 14430 14431 namespace { 14432 14433 enum ICEKind { 14434 /// This expression is an ICE. 14435 IK_ICE, 14436 /// This expression is not an ICE, but if it isn't evaluated, it's 14437 /// a legal subexpression for an ICE. This return value is used to handle 14438 /// the comma operator in C99 mode, and non-constant subexpressions. 14439 IK_ICEIfUnevaluated, 14440 /// This expression is not an ICE, and is not a legal subexpression for one. 14441 IK_NotICE 14442 }; 14443 14444 struct ICEDiag { 14445 ICEKind Kind; 14446 SourceLocation Loc; 14447 14448 ICEDiag(ICEKind IK, SourceLocation l) : Kind(IK), Loc(l) {} 14449 }; 14450 14451 } 14452 14453 static ICEDiag NoDiag() { return ICEDiag(IK_ICE, SourceLocation()); } 14454 14455 static ICEDiag Worst(ICEDiag A, ICEDiag B) { return A.Kind >= B.Kind ? A : B; } 14456 14457 static ICEDiag CheckEvalInICE(const Expr* E, const ASTContext &Ctx) { 14458 Expr::EvalResult EVResult; 14459 Expr::EvalStatus Status; 14460 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression); 14461 14462 Info.InConstantContext = true; 14463 if (!::EvaluateAsRValue(E, EVResult, Ctx, Info) || EVResult.HasSideEffects || 14464 !EVResult.Val.isInt()) 14465 return ICEDiag(IK_NotICE, E->getBeginLoc()); 14466 14467 return NoDiag(); 14468 } 14469 14470 static ICEDiag CheckICE(const Expr* E, const ASTContext &Ctx) { 14471 assert(!E->isValueDependent() && "Should not see value dependent exprs!"); 14472 if (!E->getType()->isIntegralOrEnumerationType()) 14473 return ICEDiag(IK_NotICE, E->getBeginLoc()); 14474 14475 switch (E->getStmtClass()) { 14476 #define ABSTRACT_STMT(Node) 14477 #define STMT(Node, Base) case Expr::Node##Class: 14478 #define EXPR(Node, Base) 14479 #include "clang/AST/StmtNodes.inc" 14480 case Expr::PredefinedExprClass: 14481 case Expr::FloatingLiteralClass: 14482 case Expr::ImaginaryLiteralClass: 14483 case Expr::StringLiteralClass: 14484 case Expr::ArraySubscriptExprClass: 14485 case Expr::MatrixSubscriptExprClass: 14486 case Expr::OMPArraySectionExprClass: 14487 case Expr::OMPArrayShapingExprClass: 14488 case Expr::OMPIteratorExprClass: 14489 case Expr::MemberExprClass: 14490 case Expr::CompoundAssignOperatorClass: 14491 case Expr::CompoundLiteralExprClass: 14492 case Expr::ExtVectorElementExprClass: 14493 case Expr::DesignatedInitExprClass: 14494 case Expr::ArrayInitLoopExprClass: 14495 case Expr::ArrayInitIndexExprClass: 14496 case Expr::NoInitExprClass: 14497 case Expr::DesignatedInitUpdateExprClass: 14498 case Expr::ImplicitValueInitExprClass: 14499 case Expr::ParenListExprClass: 14500 case Expr::VAArgExprClass: 14501 case Expr::AddrLabelExprClass: 14502 case Expr::StmtExprClass: 14503 case Expr::CXXMemberCallExprClass: 14504 case Expr::CUDAKernelCallExprClass: 14505 case Expr::CXXAddrspaceCastExprClass: 14506 case Expr::CXXDynamicCastExprClass: 14507 case Expr::CXXTypeidExprClass: 14508 case Expr::CXXUuidofExprClass: 14509 case Expr::MSPropertyRefExprClass: 14510 case Expr::MSPropertySubscriptExprClass: 14511 case Expr::CXXNullPtrLiteralExprClass: 14512 case Expr::UserDefinedLiteralClass: 14513 case Expr::CXXThisExprClass: 14514 case Expr::CXXThrowExprClass: 14515 case Expr::CXXNewExprClass: 14516 case Expr::CXXDeleteExprClass: 14517 case Expr::CXXPseudoDestructorExprClass: 14518 case Expr::UnresolvedLookupExprClass: 14519 case Expr::TypoExprClass: 14520 case Expr::RecoveryExprClass: 14521 case Expr::DependentScopeDeclRefExprClass: 14522 case Expr::CXXConstructExprClass: 14523 case Expr::CXXInheritedCtorInitExprClass: 14524 case Expr::CXXStdInitializerListExprClass: 14525 case Expr::CXXBindTemporaryExprClass: 14526 case Expr::ExprWithCleanupsClass: 14527 case Expr::CXXTemporaryObjectExprClass: 14528 case Expr::CXXUnresolvedConstructExprClass: 14529 case Expr::CXXDependentScopeMemberExprClass: 14530 case Expr::UnresolvedMemberExprClass: 14531 case Expr::ObjCStringLiteralClass: 14532 case Expr::ObjCBoxedExprClass: 14533 case Expr::ObjCArrayLiteralClass: 14534 case Expr::ObjCDictionaryLiteralClass: 14535 case Expr::ObjCEncodeExprClass: 14536 case Expr::ObjCMessageExprClass: 14537 case Expr::ObjCSelectorExprClass: 14538 case Expr::ObjCProtocolExprClass: 14539 case Expr::ObjCIvarRefExprClass: 14540 case Expr::ObjCPropertyRefExprClass: 14541 case Expr::ObjCSubscriptRefExprClass: 14542 case Expr::ObjCIsaExprClass: 14543 case Expr::ObjCAvailabilityCheckExprClass: 14544 case Expr::ShuffleVectorExprClass: 14545 case Expr::ConvertVectorExprClass: 14546 case Expr::BlockExprClass: 14547 case Expr::NoStmtClass: 14548 case Expr::OpaqueValueExprClass: 14549 case Expr::PackExpansionExprClass: 14550 case Expr::SubstNonTypeTemplateParmPackExprClass: 14551 case Expr::FunctionParmPackExprClass: 14552 case Expr::AsTypeExprClass: 14553 case Expr::ObjCIndirectCopyRestoreExprClass: 14554 case Expr::MaterializeTemporaryExprClass: 14555 case Expr::PseudoObjectExprClass: 14556 case Expr::AtomicExprClass: 14557 case Expr::LambdaExprClass: 14558 case Expr::CXXFoldExprClass: 14559 case Expr::CoawaitExprClass: 14560 case Expr::DependentCoawaitExprClass: 14561 case Expr::CoyieldExprClass: 14562 return ICEDiag(IK_NotICE, E->getBeginLoc()); 14563 14564 case Expr::InitListExprClass: { 14565 // C++03 [dcl.init]p13: If T is a scalar type, then a declaration of the 14566 // form "T x = { a };" is equivalent to "T x = a;". 14567 // Unless we're initializing a reference, T is a scalar as it is known to be 14568 // of integral or enumeration type. 14569 if (E->isRValue()) 14570 if (cast<InitListExpr>(E)->getNumInits() == 1) 14571 return CheckICE(cast<InitListExpr>(E)->getInit(0), Ctx); 14572 return ICEDiag(IK_NotICE, E->getBeginLoc()); 14573 } 14574 14575 case Expr::SizeOfPackExprClass: 14576 case Expr::GNUNullExprClass: 14577 case Expr::SourceLocExprClass: 14578 return NoDiag(); 14579 14580 case Expr::SubstNonTypeTemplateParmExprClass: 14581 return 14582 CheckICE(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement(), Ctx); 14583 14584 case Expr::ConstantExprClass: 14585 return CheckICE(cast<ConstantExpr>(E)->getSubExpr(), Ctx); 14586 14587 case Expr::ParenExprClass: 14588 return CheckICE(cast<ParenExpr>(E)->getSubExpr(), Ctx); 14589 case Expr::GenericSelectionExprClass: 14590 return CheckICE(cast<GenericSelectionExpr>(E)->getResultExpr(), Ctx); 14591 case Expr::IntegerLiteralClass: 14592 case Expr::FixedPointLiteralClass: 14593 case Expr::CharacterLiteralClass: 14594 case Expr::ObjCBoolLiteralExprClass: 14595 case Expr::CXXBoolLiteralExprClass: 14596 case Expr::CXXScalarValueInitExprClass: 14597 case Expr::TypeTraitExprClass: 14598 case Expr::ConceptSpecializationExprClass: 14599 case Expr::RequiresExprClass: 14600 case Expr::ArrayTypeTraitExprClass: 14601 case Expr::ExpressionTraitExprClass: 14602 case Expr::CXXNoexceptExprClass: 14603 return NoDiag(); 14604 case Expr::CallExprClass: 14605 case Expr::CXXOperatorCallExprClass: { 14606 // C99 6.6/3 allows function calls within unevaluated subexpressions of 14607 // constant expressions, but they can never be ICEs because an ICE cannot 14608 // contain an operand of (pointer to) function type. 14609 const CallExpr *CE = cast<CallExpr>(E); 14610 if (CE->getBuiltinCallee()) 14611 return CheckEvalInICE(E, Ctx); 14612 return ICEDiag(IK_NotICE, E->getBeginLoc()); 14613 } 14614 case Expr::CXXRewrittenBinaryOperatorClass: 14615 return CheckICE(cast<CXXRewrittenBinaryOperator>(E)->getSemanticForm(), 14616 Ctx); 14617 case Expr::DeclRefExprClass: { 14618 if (isa<EnumConstantDecl>(cast<DeclRefExpr>(E)->getDecl())) 14619 return NoDiag(); 14620 const ValueDecl *D = cast<DeclRefExpr>(E)->getDecl(); 14621 if (Ctx.getLangOpts().CPlusPlus && 14622 D && IsConstNonVolatile(D->getType())) { 14623 // Parameter variables are never constants. Without this check, 14624 // getAnyInitializer() can find a default argument, which leads 14625 // to chaos. 14626 if (isa<ParmVarDecl>(D)) 14627 return ICEDiag(IK_NotICE, cast<DeclRefExpr>(E)->getLocation()); 14628 14629 // C++ 7.1.5.1p2 14630 // A variable of non-volatile const-qualified integral or enumeration 14631 // type initialized by an ICE can be used in ICEs. 14632 if (const VarDecl *Dcl = dyn_cast<VarDecl>(D)) { 14633 if (!Dcl->getType()->isIntegralOrEnumerationType()) 14634 return ICEDiag(IK_NotICE, cast<DeclRefExpr>(E)->getLocation()); 14635 14636 const VarDecl *VD; 14637 // Look for a declaration of this variable that has an initializer, and 14638 // check whether it is an ICE. 14639 if (Dcl->getAnyInitializer(VD) && VD->checkInitIsICE()) 14640 return NoDiag(); 14641 else 14642 return ICEDiag(IK_NotICE, cast<DeclRefExpr>(E)->getLocation()); 14643 } 14644 } 14645 return ICEDiag(IK_NotICE, E->getBeginLoc()); 14646 } 14647 case Expr::UnaryOperatorClass: { 14648 const UnaryOperator *Exp = cast<UnaryOperator>(E); 14649 switch (Exp->getOpcode()) { 14650 case UO_PostInc: 14651 case UO_PostDec: 14652 case UO_PreInc: 14653 case UO_PreDec: 14654 case UO_AddrOf: 14655 case UO_Deref: 14656 case UO_Coawait: 14657 // C99 6.6/3 allows increment and decrement within unevaluated 14658 // subexpressions of constant expressions, but they can never be ICEs 14659 // because an ICE cannot contain an lvalue operand. 14660 return ICEDiag(IK_NotICE, E->getBeginLoc()); 14661 case UO_Extension: 14662 case UO_LNot: 14663 case UO_Plus: 14664 case UO_Minus: 14665 case UO_Not: 14666 case UO_Real: 14667 case UO_Imag: 14668 return CheckICE(Exp->getSubExpr(), Ctx); 14669 } 14670 llvm_unreachable("invalid unary operator class"); 14671 } 14672 case Expr::OffsetOfExprClass: { 14673 // Note that per C99, offsetof must be an ICE. And AFAIK, using 14674 // EvaluateAsRValue matches the proposed gcc behavior for cases like 14675 // "offsetof(struct s{int x[4];}, x[1.0])". This doesn't affect 14676 // compliance: we should warn earlier for offsetof expressions with 14677 // array subscripts that aren't ICEs, and if the array subscripts 14678 // are ICEs, the value of the offsetof must be an integer constant. 14679 return CheckEvalInICE(E, Ctx); 14680 } 14681 case Expr::UnaryExprOrTypeTraitExprClass: { 14682 const UnaryExprOrTypeTraitExpr *Exp = cast<UnaryExprOrTypeTraitExpr>(E); 14683 if ((Exp->getKind() == UETT_SizeOf) && 14684 Exp->getTypeOfArgument()->isVariableArrayType()) 14685 return ICEDiag(IK_NotICE, E->getBeginLoc()); 14686 return NoDiag(); 14687 } 14688 case Expr::BinaryOperatorClass: { 14689 const BinaryOperator *Exp = cast<BinaryOperator>(E); 14690 switch (Exp->getOpcode()) { 14691 case BO_PtrMemD: 14692 case BO_PtrMemI: 14693 case BO_Assign: 14694 case BO_MulAssign: 14695 case BO_DivAssign: 14696 case BO_RemAssign: 14697 case BO_AddAssign: 14698 case BO_SubAssign: 14699 case BO_ShlAssign: 14700 case BO_ShrAssign: 14701 case BO_AndAssign: 14702 case BO_XorAssign: 14703 case BO_OrAssign: 14704 // C99 6.6/3 allows assignments within unevaluated subexpressions of 14705 // constant expressions, but they can never be ICEs because an ICE cannot 14706 // contain an lvalue operand. 14707 return ICEDiag(IK_NotICE, E->getBeginLoc()); 14708 14709 case BO_Mul: 14710 case BO_Div: 14711 case BO_Rem: 14712 case BO_Add: 14713 case BO_Sub: 14714 case BO_Shl: 14715 case BO_Shr: 14716 case BO_LT: 14717 case BO_GT: 14718 case BO_LE: 14719 case BO_GE: 14720 case BO_EQ: 14721 case BO_NE: 14722 case BO_And: 14723 case BO_Xor: 14724 case BO_Or: 14725 case BO_Comma: 14726 case BO_Cmp: { 14727 ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx); 14728 ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx); 14729 if (Exp->getOpcode() == BO_Div || 14730 Exp->getOpcode() == BO_Rem) { 14731 // EvaluateAsRValue gives an error for undefined Div/Rem, so make sure 14732 // we don't evaluate one. 14733 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE) { 14734 llvm::APSInt REval = Exp->getRHS()->EvaluateKnownConstInt(Ctx); 14735 if (REval == 0) 14736 return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc()); 14737 if (REval.isSigned() && REval.isAllOnesValue()) { 14738 llvm::APSInt LEval = Exp->getLHS()->EvaluateKnownConstInt(Ctx); 14739 if (LEval.isMinSignedValue()) 14740 return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc()); 14741 } 14742 } 14743 } 14744 if (Exp->getOpcode() == BO_Comma) { 14745 if (Ctx.getLangOpts().C99) { 14746 // C99 6.6p3 introduces a strange edge case: comma can be in an ICE 14747 // if it isn't evaluated. 14748 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE) 14749 return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc()); 14750 } else { 14751 // In both C89 and C++, commas in ICEs are illegal. 14752 return ICEDiag(IK_NotICE, E->getBeginLoc()); 14753 } 14754 } 14755 return Worst(LHSResult, RHSResult); 14756 } 14757 case BO_LAnd: 14758 case BO_LOr: { 14759 ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx); 14760 ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx); 14761 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICEIfUnevaluated) { 14762 // Rare case where the RHS has a comma "side-effect"; we need 14763 // to actually check the condition to see whether the side 14764 // with the comma is evaluated. 14765 if ((Exp->getOpcode() == BO_LAnd) != 14766 (Exp->getLHS()->EvaluateKnownConstInt(Ctx) == 0)) 14767 return RHSResult; 14768 return NoDiag(); 14769 } 14770 14771 return Worst(LHSResult, RHSResult); 14772 } 14773 } 14774 llvm_unreachable("invalid binary operator kind"); 14775 } 14776 case Expr::ImplicitCastExprClass: 14777 case Expr::CStyleCastExprClass: 14778 case Expr::CXXFunctionalCastExprClass: 14779 case Expr::CXXStaticCastExprClass: 14780 case Expr::CXXReinterpretCastExprClass: 14781 case Expr::CXXConstCastExprClass: 14782 case Expr::ObjCBridgedCastExprClass: { 14783 const Expr *SubExpr = cast<CastExpr>(E)->getSubExpr(); 14784 if (isa<ExplicitCastExpr>(E)) { 14785 if (const FloatingLiteral *FL 14786 = dyn_cast<FloatingLiteral>(SubExpr->IgnoreParenImpCasts())) { 14787 unsigned DestWidth = Ctx.getIntWidth(E->getType()); 14788 bool DestSigned = E->getType()->isSignedIntegerOrEnumerationType(); 14789 APSInt IgnoredVal(DestWidth, !DestSigned); 14790 bool Ignored; 14791 // If the value does not fit in the destination type, the behavior is 14792 // undefined, so we are not required to treat it as a constant 14793 // expression. 14794 if (FL->getValue().convertToInteger(IgnoredVal, 14795 llvm::APFloat::rmTowardZero, 14796 &Ignored) & APFloat::opInvalidOp) 14797 return ICEDiag(IK_NotICE, E->getBeginLoc()); 14798 return NoDiag(); 14799 } 14800 } 14801 switch (cast<CastExpr>(E)->getCastKind()) { 14802 case CK_LValueToRValue: 14803 case CK_AtomicToNonAtomic: 14804 case CK_NonAtomicToAtomic: 14805 case CK_NoOp: 14806 case CK_IntegralToBoolean: 14807 case CK_IntegralCast: 14808 return CheckICE(SubExpr, Ctx); 14809 default: 14810 return ICEDiag(IK_NotICE, E->getBeginLoc()); 14811 } 14812 } 14813 case Expr::BinaryConditionalOperatorClass: { 14814 const BinaryConditionalOperator *Exp = cast<BinaryConditionalOperator>(E); 14815 ICEDiag CommonResult = CheckICE(Exp->getCommon(), Ctx); 14816 if (CommonResult.Kind == IK_NotICE) return CommonResult; 14817 ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx); 14818 if (FalseResult.Kind == IK_NotICE) return FalseResult; 14819 if (CommonResult.Kind == IK_ICEIfUnevaluated) return CommonResult; 14820 if (FalseResult.Kind == IK_ICEIfUnevaluated && 14821 Exp->getCommon()->EvaluateKnownConstInt(Ctx) != 0) return NoDiag(); 14822 return FalseResult; 14823 } 14824 case Expr::ConditionalOperatorClass: { 14825 const ConditionalOperator *Exp = cast<ConditionalOperator>(E); 14826 // If the condition (ignoring parens) is a __builtin_constant_p call, 14827 // then only the true side is actually considered in an integer constant 14828 // expression, and it is fully evaluated. This is an important GNU 14829 // extension. See GCC PR38377 for discussion. 14830 if (const CallExpr *CallCE 14831 = dyn_cast<CallExpr>(Exp->getCond()->IgnoreParenCasts())) 14832 if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p) 14833 return CheckEvalInICE(E, Ctx); 14834 ICEDiag CondResult = CheckICE(Exp->getCond(), Ctx); 14835 if (CondResult.Kind == IK_NotICE) 14836 return CondResult; 14837 14838 ICEDiag TrueResult = CheckICE(Exp->getTrueExpr(), Ctx); 14839 ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx); 14840 14841 if (TrueResult.Kind == IK_NotICE) 14842 return TrueResult; 14843 if (FalseResult.Kind == IK_NotICE) 14844 return FalseResult; 14845 if (CondResult.Kind == IK_ICEIfUnevaluated) 14846 return CondResult; 14847 if (TrueResult.Kind == IK_ICE && FalseResult.Kind == IK_ICE) 14848 return NoDiag(); 14849 // Rare case where the diagnostics depend on which side is evaluated 14850 // Note that if we get here, CondResult is 0, and at least one of 14851 // TrueResult and FalseResult is non-zero. 14852 if (Exp->getCond()->EvaluateKnownConstInt(Ctx) == 0) 14853 return FalseResult; 14854 return TrueResult; 14855 } 14856 case Expr::CXXDefaultArgExprClass: 14857 return CheckICE(cast<CXXDefaultArgExpr>(E)->getExpr(), Ctx); 14858 case Expr::CXXDefaultInitExprClass: 14859 return CheckICE(cast<CXXDefaultInitExpr>(E)->getExpr(), Ctx); 14860 case Expr::ChooseExprClass: { 14861 return CheckICE(cast<ChooseExpr>(E)->getChosenSubExpr(), Ctx); 14862 } 14863 case Expr::BuiltinBitCastExprClass: { 14864 if (!checkBitCastConstexprEligibility(nullptr, Ctx, cast<CastExpr>(E))) 14865 return ICEDiag(IK_NotICE, E->getBeginLoc()); 14866 return CheckICE(cast<CastExpr>(E)->getSubExpr(), Ctx); 14867 } 14868 } 14869 14870 llvm_unreachable("Invalid StmtClass!"); 14871 } 14872 14873 /// Evaluate an expression as a C++11 integral constant expression. 14874 static bool EvaluateCPlusPlus11IntegralConstantExpr(const ASTContext &Ctx, 14875 const Expr *E, 14876 llvm::APSInt *Value, 14877 SourceLocation *Loc) { 14878 if (!E->getType()->isIntegralOrUnscopedEnumerationType()) { 14879 if (Loc) *Loc = E->getExprLoc(); 14880 return false; 14881 } 14882 14883 APValue Result; 14884 if (!E->isCXX11ConstantExpr(Ctx, &Result, Loc)) 14885 return false; 14886 14887 if (!Result.isInt()) { 14888 if (Loc) *Loc = E->getExprLoc(); 14889 return false; 14890 } 14891 14892 if (Value) *Value = Result.getInt(); 14893 return true; 14894 } 14895 14896 bool Expr::isIntegerConstantExpr(const ASTContext &Ctx, 14897 SourceLocation *Loc) const { 14898 assert(!isValueDependent() && 14899 "Expression evaluator can't be called on a dependent expression."); 14900 14901 if (Ctx.getLangOpts().CPlusPlus11) 14902 return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, nullptr, Loc); 14903 14904 ICEDiag D = CheckICE(this, Ctx); 14905 if (D.Kind != IK_ICE) { 14906 if (Loc) *Loc = D.Loc; 14907 return false; 14908 } 14909 return true; 14910 } 14911 14912 bool Expr::isIntegerConstantExpr(llvm::APSInt &Value, const ASTContext &Ctx, 14913 SourceLocation *Loc, bool isEvaluated) const { 14914 assert(!isValueDependent() && 14915 "Expression evaluator can't be called on a dependent expression."); 14916 14917 if (Ctx.getLangOpts().CPlusPlus11) 14918 return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, &Value, Loc); 14919 14920 if (!isIntegerConstantExpr(Ctx, Loc)) 14921 return false; 14922 14923 // The only possible side-effects here are due to UB discovered in the 14924 // evaluation (for instance, INT_MAX + 1). In such a case, we are still 14925 // required to treat the expression as an ICE, so we produce the folded 14926 // value. 14927 EvalResult ExprResult; 14928 Expr::EvalStatus Status; 14929 EvalInfo Info(Ctx, Status, EvalInfo::EM_IgnoreSideEffects); 14930 Info.InConstantContext = true; 14931 14932 if (!::EvaluateAsInt(this, ExprResult, Ctx, SE_AllowSideEffects, Info)) 14933 llvm_unreachable("ICE cannot be evaluated!"); 14934 14935 Value = ExprResult.Val.getInt(); 14936 return true; 14937 } 14938 14939 bool Expr::isCXX98IntegralConstantExpr(const ASTContext &Ctx) const { 14940 assert(!isValueDependent() && 14941 "Expression evaluator can't be called on a dependent expression."); 14942 14943 return CheckICE(this, Ctx).Kind == IK_ICE; 14944 } 14945 14946 bool Expr::isCXX11ConstantExpr(const ASTContext &Ctx, APValue *Result, 14947 SourceLocation *Loc) const { 14948 assert(!isValueDependent() && 14949 "Expression evaluator can't be called on a dependent expression."); 14950 14951 // We support this checking in C++98 mode in order to diagnose compatibility 14952 // issues. 14953 assert(Ctx.getLangOpts().CPlusPlus); 14954 14955 // Build evaluation settings. 14956 Expr::EvalStatus Status; 14957 SmallVector<PartialDiagnosticAt, 8> Diags; 14958 Status.Diag = &Diags; 14959 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression); 14960 14961 APValue Scratch; 14962 bool IsConstExpr = 14963 ::EvaluateAsRValue(Info, this, Result ? *Result : Scratch) && 14964 // FIXME: We don't produce a diagnostic for this, but the callers that 14965 // call us on arbitrary full-expressions should generally not care. 14966 Info.discardCleanups() && !Status.HasSideEffects; 14967 14968 if (!Diags.empty()) { 14969 IsConstExpr = false; 14970 if (Loc) *Loc = Diags[0].first; 14971 } else if (!IsConstExpr) { 14972 // FIXME: This shouldn't happen. 14973 if (Loc) *Loc = getExprLoc(); 14974 } 14975 14976 return IsConstExpr; 14977 } 14978 14979 bool Expr::EvaluateWithSubstitution(APValue &Value, ASTContext &Ctx, 14980 const FunctionDecl *Callee, 14981 ArrayRef<const Expr*> Args, 14982 const Expr *This) const { 14983 assert(!isValueDependent() && 14984 "Expression evaluator can't be called on a dependent expression."); 14985 14986 Expr::EvalStatus Status; 14987 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpressionUnevaluated); 14988 Info.InConstantContext = true; 14989 14990 LValue ThisVal; 14991 const LValue *ThisPtr = nullptr; 14992 if (This) { 14993 #ifndef NDEBUG 14994 auto *MD = dyn_cast<CXXMethodDecl>(Callee); 14995 assert(MD && "Don't provide `this` for non-methods."); 14996 assert(!MD->isStatic() && "Don't provide `this` for static methods."); 14997 #endif 14998 if (!This->isValueDependent() && 14999 EvaluateObjectArgument(Info, This, ThisVal) && 15000 !Info.EvalStatus.HasSideEffects) 15001 ThisPtr = &ThisVal; 15002 15003 // Ignore any side-effects from a failed evaluation. This is safe because 15004 // they can't interfere with any other argument evaluation. 15005 Info.EvalStatus.HasSideEffects = false; 15006 } 15007 15008 ArgVector ArgValues(Args.size()); 15009 for (ArrayRef<const Expr*>::iterator I = Args.begin(), E = Args.end(); 15010 I != E; ++I) { 15011 if ((*I)->isValueDependent() || 15012 !Evaluate(ArgValues[I - Args.begin()], Info, *I) || 15013 Info.EvalStatus.HasSideEffects) 15014 // If evaluation fails, throw away the argument entirely. 15015 ArgValues[I - Args.begin()] = APValue(); 15016 15017 // Ignore any side-effects from a failed evaluation. This is safe because 15018 // they can't interfere with any other argument evaluation. 15019 Info.EvalStatus.HasSideEffects = false; 15020 } 15021 15022 // Parameter cleanups happen in the caller and are not part of this 15023 // evaluation. 15024 Info.discardCleanups(); 15025 Info.EvalStatus.HasSideEffects = false; 15026 15027 // Build fake call to Callee. 15028 CallStackFrame Frame(Info, Callee->getLocation(), Callee, ThisPtr, 15029 ArgValues.data()); 15030 // FIXME: Missing ExprWithCleanups in enable_if conditions? 15031 FullExpressionRAII Scope(Info); 15032 return Evaluate(Value, Info, this) && Scope.destroy() && 15033 !Info.EvalStatus.HasSideEffects; 15034 } 15035 15036 bool Expr::isPotentialConstantExpr(const FunctionDecl *FD, 15037 SmallVectorImpl< 15038 PartialDiagnosticAt> &Diags) { 15039 // FIXME: It would be useful to check constexpr function templates, but at the 15040 // moment the constant expression evaluator cannot cope with the non-rigorous 15041 // ASTs which we build for dependent expressions. 15042 if (FD->isDependentContext()) 15043 return true; 15044 15045 // Bail out if a constexpr constructor has an initializer that contains an 15046 // error. We deliberately don't produce a diagnostic, as we have produced a 15047 // relevant diagnostic when parsing the error initializer. 15048 if (const auto *Ctor = dyn_cast<CXXConstructorDecl>(FD)) { 15049 for (const auto *InitExpr : Ctor->inits()) { 15050 if (InitExpr->getInit() && InitExpr->getInit()->containsErrors()) 15051 return false; 15052 } 15053 } 15054 Expr::EvalStatus Status; 15055 Status.Diag = &Diags; 15056 15057 EvalInfo Info(FD->getASTContext(), Status, EvalInfo::EM_ConstantExpression); 15058 Info.InConstantContext = true; 15059 Info.CheckingPotentialConstantExpression = true; 15060 15061 // The constexpr VM attempts to compile all methods to bytecode here. 15062 if (Info.EnableNewConstInterp) { 15063 Info.Ctx.getInterpContext().isPotentialConstantExpr(Info, FD); 15064 return Diags.empty(); 15065 } 15066 15067 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD); 15068 const CXXRecordDecl *RD = MD ? MD->getParent()->getCanonicalDecl() : nullptr; 15069 15070 // Fabricate an arbitrary expression on the stack and pretend that it 15071 // is a temporary being used as the 'this' pointer. 15072 LValue This; 15073 ImplicitValueInitExpr VIE(RD ? Info.Ctx.getRecordType(RD) : Info.Ctx.IntTy); 15074 This.set({&VIE, Info.CurrentCall->Index}); 15075 15076 ArrayRef<const Expr*> Args; 15077 15078 APValue Scratch; 15079 if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) { 15080 // Evaluate the call as a constant initializer, to allow the construction 15081 // of objects of non-literal types. 15082 Info.setEvaluatingDecl(This.getLValueBase(), Scratch); 15083 HandleConstructorCall(&VIE, This, Args, CD, Info, Scratch); 15084 } else { 15085 SourceLocation Loc = FD->getLocation(); 15086 HandleFunctionCall(Loc, FD, (MD && MD->isInstance()) ? &This : nullptr, 15087 Args, FD->getBody(), Info, Scratch, nullptr); 15088 } 15089 15090 return Diags.empty(); 15091 } 15092 15093 bool Expr::isPotentialConstantExprUnevaluated(Expr *E, 15094 const FunctionDecl *FD, 15095 SmallVectorImpl< 15096 PartialDiagnosticAt> &Diags) { 15097 assert(!E->isValueDependent() && 15098 "Expression evaluator can't be called on a dependent expression."); 15099 15100 Expr::EvalStatus Status; 15101 Status.Diag = &Diags; 15102 15103 EvalInfo Info(FD->getASTContext(), Status, 15104 EvalInfo::EM_ConstantExpressionUnevaluated); 15105 Info.InConstantContext = true; 15106 Info.CheckingPotentialConstantExpression = true; 15107 15108 // Fabricate a call stack frame to give the arguments a plausible cover story. 15109 ArrayRef<const Expr*> Args; 15110 ArgVector ArgValues(0); 15111 bool Success = EvaluateArgs(Args, ArgValues, Info, FD); 15112 (void)Success; 15113 assert(Success && 15114 "Failed to set up arguments for potential constant evaluation"); 15115 CallStackFrame Frame(Info, SourceLocation(), FD, nullptr, ArgValues.data()); 15116 15117 APValue ResultScratch; 15118 Evaluate(ResultScratch, Info, E); 15119 return Diags.empty(); 15120 } 15121 15122 bool Expr::tryEvaluateObjectSize(uint64_t &Result, ASTContext &Ctx, 15123 unsigned Type) const { 15124 if (!getType()->isPointerType()) 15125 return false; 15126 15127 Expr::EvalStatus Status; 15128 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold); 15129 return tryEvaluateBuiltinObjectSize(this, Type, Info, Result); 15130 } 15131