1 //===--- CGExprCXX.cpp - Emit LLVM Code for C++ expressions ---------------===// 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 contains code dealing with code generation of C++ expressions 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "CGCUDARuntime.h" 14 #include "CGCXXABI.h" 15 #include "CGDebugInfo.h" 16 #include "CGObjCRuntime.h" 17 #include "CodeGenFunction.h" 18 #include "ConstantEmitter.h" 19 #include "TargetInfo.h" 20 #include "clang/Basic/CodeGenOptions.h" 21 #include "clang/CodeGen/CGFunctionInfo.h" 22 #include "llvm/IR/Intrinsics.h" 23 24 using namespace clang; 25 using namespace CodeGen; 26 27 namespace { 28 struct MemberCallInfo { 29 RequiredArgs ReqArgs; 30 // Number of prefix arguments for the call. Ignores the `this` pointer. 31 unsigned PrefixSize; 32 }; 33 } 34 35 static MemberCallInfo 36 commonEmitCXXMemberOrOperatorCall(CodeGenFunction &CGF, GlobalDecl GD, 37 llvm::Value *This, llvm::Value *ImplicitParam, 38 QualType ImplicitParamTy, const CallExpr *CE, 39 CallArgList &Args, CallArgList *RtlArgs) { 40 auto *MD = cast<CXXMethodDecl>(GD.getDecl()); 41 42 assert(CE == nullptr || isa<CXXMemberCallExpr>(CE) || 43 isa<CXXOperatorCallExpr>(CE)); 44 assert(MD->isImplicitObjectMemberFunction() && 45 "Trying to emit a member or operator call expr on a static method!"); 46 47 // Push the this ptr. 48 const CXXRecordDecl *RD = 49 CGF.CGM.getCXXABI().getThisArgumentTypeForMethod(GD); 50 Args.add(RValue::get(This), CGF.getTypes().DeriveThisType(RD, MD)); 51 52 // If there is an implicit parameter (e.g. VTT), emit it. 53 if (ImplicitParam) { 54 Args.add(RValue::get(ImplicitParam), ImplicitParamTy); 55 } 56 57 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>(); 58 RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, Args.size()); 59 unsigned PrefixSize = Args.size() - 1; 60 61 // And the rest of the call args. 62 if (RtlArgs) { 63 // Special case: if the caller emitted the arguments right-to-left already 64 // (prior to emitting the *this argument), we're done. This happens for 65 // assignment operators. 66 Args.addFrom(*RtlArgs); 67 } else if (CE) { 68 // Special case: skip first argument of CXXOperatorCall (it is "this"). 69 unsigned ArgsToSkip = 0; 70 if (const auto *Op = dyn_cast<CXXOperatorCallExpr>(CE)) { 71 if (const auto *M = dyn_cast<CXXMethodDecl>(Op->getCalleeDecl())) 72 ArgsToSkip = 73 static_cast<unsigned>(!M->isExplicitObjectMemberFunction()); 74 } 75 CGF.EmitCallArgs(Args, FPT, drop_begin(CE->arguments(), ArgsToSkip), 76 CE->getDirectCallee()); 77 } else { 78 assert( 79 FPT->getNumParams() == 0 && 80 "No CallExpr specified for function with non-zero number of arguments"); 81 } 82 return {required, PrefixSize}; 83 } 84 85 RValue CodeGenFunction::EmitCXXMemberOrOperatorCall( 86 const CXXMethodDecl *MD, const CGCallee &Callee, 87 ReturnValueSlot ReturnValue, 88 llvm::Value *This, llvm::Value *ImplicitParam, QualType ImplicitParamTy, 89 const CallExpr *CE, CallArgList *RtlArgs) { 90 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>(); 91 CallArgList Args; 92 MemberCallInfo CallInfo = commonEmitCXXMemberOrOperatorCall( 93 *this, MD, This, ImplicitParam, ImplicitParamTy, CE, Args, RtlArgs); 94 auto &FnInfo = CGM.getTypes().arrangeCXXMethodCall( 95 Args, FPT, CallInfo.ReqArgs, CallInfo.PrefixSize); 96 return EmitCall(FnInfo, Callee, ReturnValue, Args, nullptr, 97 CE && CE == MustTailCall, 98 CE ? CE->getExprLoc() : SourceLocation()); 99 } 100 101 RValue CodeGenFunction::EmitCXXDestructorCall( 102 GlobalDecl Dtor, const CGCallee &Callee, llvm::Value *This, QualType ThisTy, 103 llvm::Value *ImplicitParam, QualType ImplicitParamTy, const CallExpr *CE) { 104 const CXXMethodDecl *DtorDecl = cast<CXXMethodDecl>(Dtor.getDecl()); 105 106 assert(!ThisTy.isNull()); 107 assert(ThisTy->getAsCXXRecordDecl() == DtorDecl->getParent() && 108 "Pointer/Object mixup"); 109 110 LangAS SrcAS = ThisTy.getAddressSpace(); 111 LangAS DstAS = DtorDecl->getMethodQualifiers().getAddressSpace(); 112 if (SrcAS != DstAS) { 113 QualType DstTy = DtorDecl->getThisType(); 114 llvm::Type *NewType = CGM.getTypes().ConvertType(DstTy); 115 This = getTargetHooks().performAddrSpaceCast(*this, This, SrcAS, DstAS, 116 NewType); 117 } 118 119 CallArgList Args; 120 commonEmitCXXMemberOrOperatorCall(*this, Dtor, This, ImplicitParam, 121 ImplicitParamTy, CE, Args, nullptr); 122 return EmitCall(CGM.getTypes().arrangeCXXStructorDeclaration(Dtor), Callee, 123 ReturnValueSlot(), Args, nullptr, CE && CE == MustTailCall, 124 CE ? CE->getExprLoc() : SourceLocation{}); 125 } 126 127 RValue CodeGenFunction::EmitCXXPseudoDestructorExpr( 128 const CXXPseudoDestructorExpr *E) { 129 QualType DestroyedType = E->getDestroyedType(); 130 if (DestroyedType.hasStrongOrWeakObjCLifetime()) { 131 // Automatic Reference Counting: 132 // If the pseudo-expression names a retainable object with weak or 133 // strong lifetime, the object shall be released. 134 Expr *BaseExpr = E->getBase(); 135 Address BaseValue = Address::invalid(); 136 Qualifiers BaseQuals; 137 138 // If this is s.x, emit s as an lvalue. If it is s->x, emit s as a scalar. 139 if (E->isArrow()) { 140 BaseValue = EmitPointerWithAlignment(BaseExpr); 141 const auto *PTy = BaseExpr->getType()->castAs<PointerType>(); 142 BaseQuals = PTy->getPointeeType().getQualifiers(); 143 } else { 144 LValue BaseLV = EmitLValue(BaseExpr); 145 BaseValue = BaseLV.getAddress(); 146 QualType BaseTy = BaseExpr->getType(); 147 BaseQuals = BaseTy.getQualifiers(); 148 } 149 150 switch (DestroyedType.getObjCLifetime()) { 151 case Qualifiers::OCL_None: 152 case Qualifiers::OCL_ExplicitNone: 153 case Qualifiers::OCL_Autoreleasing: 154 break; 155 156 case Qualifiers::OCL_Strong: 157 EmitARCRelease(Builder.CreateLoad(BaseValue, 158 DestroyedType.isVolatileQualified()), 159 ARCPreciseLifetime); 160 break; 161 162 case Qualifiers::OCL_Weak: 163 EmitARCDestroyWeak(BaseValue); 164 break; 165 } 166 } else { 167 // C++ [expr.pseudo]p1: 168 // The result shall only be used as the operand for the function call 169 // operator (), and the result of such a call has type void. The only 170 // effect is the evaluation of the postfix-expression before the dot or 171 // arrow. 172 EmitIgnoredExpr(E->getBase()); 173 } 174 175 return RValue::get(nullptr); 176 } 177 178 static CXXRecordDecl *getCXXRecord(const Expr *E) { 179 QualType T = E->getType(); 180 if (const PointerType *PTy = T->getAs<PointerType>()) 181 T = PTy->getPointeeType(); 182 const RecordType *Ty = T->castAs<RecordType>(); 183 return cast<CXXRecordDecl>(Ty->getDecl()); 184 } 185 186 // Note: This function also emit constructor calls to support a MSVC 187 // extensions allowing explicit constructor function call. 188 RValue CodeGenFunction::EmitCXXMemberCallExpr(const CXXMemberCallExpr *CE, 189 ReturnValueSlot ReturnValue) { 190 const Expr *callee = CE->getCallee()->IgnoreParens(); 191 192 if (isa<BinaryOperator>(callee)) 193 return EmitCXXMemberPointerCallExpr(CE, ReturnValue); 194 195 const MemberExpr *ME = cast<MemberExpr>(callee); 196 const CXXMethodDecl *MD = cast<CXXMethodDecl>(ME->getMemberDecl()); 197 198 if (MD->isStatic()) { 199 // The method is static, emit it as we would a regular call. 200 CGCallee callee = 201 CGCallee::forDirect(CGM.GetAddrOfFunction(MD), GlobalDecl(MD)); 202 return EmitCall(getContext().getPointerType(MD->getType()), callee, CE, 203 ReturnValue); 204 } 205 206 bool HasQualifier = ME->hasQualifier(); 207 NestedNameSpecifier *Qualifier = HasQualifier ? ME->getQualifier() : nullptr; 208 bool IsArrow = ME->isArrow(); 209 const Expr *Base = ME->getBase(); 210 211 return EmitCXXMemberOrOperatorMemberCallExpr( 212 CE, MD, ReturnValue, HasQualifier, Qualifier, IsArrow, Base); 213 } 214 215 RValue CodeGenFunction::EmitCXXMemberOrOperatorMemberCallExpr( 216 const CallExpr *CE, const CXXMethodDecl *MD, ReturnValueSlot ReturnValue, 217 bool HasQualifier, NestedNameSpecifier *Qualifier, bool IsArrow, 218 const Expr *Base) { 219 assert(isa<CXXMemberCallExpr>(CE) || isa<CXXOperatorCallExpr>(CE)); 220 221 // Compute the object pointer. 222 bool CanUseVirtualCall = MD->isVirtual() && !HasQualifier; 223 224 const CXXMethodDecl *DevirtualizedMethod = nullptr; 225 if (CanUseVirtualCall && 226 MD->getDevirtualizedMethod(Base, getLangOpts().AppleKext)) { 227 const CXXRecordDecl *BestDynamicDecl = Base->getBestDynamicClassType(); 228 DevirtualizedMethod = MD->getCorrespondingMethodInClass(BestDynamicDecl); 229 assert(DevirtualizedMethod); 230 const CXXRecordDecl *DevirtualizedClass = DevirtualizedMethod->getParent(); 231 const Expr *Inner = Base->IgnoreParenBaseCasts(); 232 if (DevirtualizedMethod->getReturnType().getCanonicalType() != 233 MD->getReturnType().getCanonicalType()) 234 // If the return types are not the same, this might be a case where more 235 // code needs to run to compensate for it. For example, the derived 236 // method might return a type that inherits form from the return 237 // type of MD and has a prefix. 238 // For now we just avoid devirtualizing these covariant cases. 239 DevirtualizedMethod = nullptr; 240 else if (getCXXRecord(Inner) == DevirtualizedClass) 241 // If the class of the Inner expression is where the dynamic method 242 // is defined, build the this pointer from it. 243 Base = Inner; 244 else if (getCXXRecord(Base) != DevirtualizedClass) { 245 // If the method is defined in a class that is not the best dynamic 246 // one or the one of the full expression, we would have to build 247 // a derived-to-base cast to compute the correct this pointer, but 248 // we don't have support for that yet, so do a virtual call. 249 DevirtualizedMethod = nullptr; 250 } 251 } 252 253 bool TrivialForCodegen = 254 MD->isTrivial() || (MD->isDefaulted() && MD->getParent()->isUnion()); 255 bool TrivialAssignment = 256 TrivialForCodegen && 257 (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) && 258 !MD->getParent()->mayInsertExtraPadding(); 259 260 // C++17 demands that we evaluate the RHS of a (possibly-compound) assignment 261 // operator before the LHS. 262 CallArgList RtlArgStorage; 263 CallArgList *RtlArgs = nullptr; 264 LValue TrivialAssignmentRHS; 265 if (auto *OCE = dyn_cast<CXXOperatorCallExpr>(CE)) { 266 if (OCE->isAssignmentOp()) { 267 if (TrivialAssignment) { 268 TrivialAssignmentRHS = EmitLValue(CE->getArg(1)); 269 } else { 270 RtlArgs = &RtlArgStorage; 271 EmitCallArgs(*RtlArgs, MD->getType()->castAs<FunctionProtoType>(), 272 drop_begin(CE->arguments(), 1), CE->getDirectCallee(), 273 /*ParamsToSkip*/0, EvaluationOrder::ForceRightToLeft); 274 } 275 } 276 } 277 278 LValue This; 279 if (IsArrow) { 280 LValueBaseInfo BaseInfo; 281 TBAAAccessInfo TBAAInfo; 282 Address ThisValue = EmitPointerWithAlignment(Base, &BaseInfo, &TBAAInfo); 283 This = MakeAddrLValue(ThisValue, Base->getType()->getPointeeType(), 284 BaseInfo, TBAAInfo); 285 } else { 286 This = EmitLValue(Base); 287 } 288 289 if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(MD)) { 290 // This is the MSVC p->Ctor::Ctor(...) extension. We assume that's 291 // constructing a new complete object of type Ctor. 292 assert(!RtlArgs); 293 assert(ReturnValue.isNull() && "Constructor shouldn't have return value"); 294 CallArgList Args; 295 commonEmitCXXMemberOrOperatorCall( 296 *this, {Ctor, Ctor_Complete}, This.getPointer(*this), 297 /*ImplicitParam=*/nullptr, 298 /*ImplicitParamTy=*/QualType(), CE, Args, nullptr); 299 300 EmitCXXConstructorCall(Ctor, Ctor_Complete, /*ForVirtualBase=*/false, 301 /*Delegating=*/false, This.getAddress(), Args, 302 AggValueSlot::DoesNotOverlap, CE->getExprLoc(), 303 /*NewPointerIsChecked=*/false); 304 return RValue::get(nullptr); 305 } 306 307 if (TrivialForCodegen) { 308 if (isa<CXXDestructorDecl>(MD)) 309 return RValue::get(nullptr); 310 311 if (TrivialAssignment) { 312 // We don't like to generate the trivial copy/move assignment operator 313 // when it isn't necessary; just produce the proper effect here. 314 // It's important that we use the result of EmitLValue here rather than 315 // emitting call arguments, in order to preserve TBAA information from 316 // the RHS. 317 LValue RHS = isa<CXXOperatorCallExpr>(CE) 318 ? TrivialAssignmentRHS 319 : EmitLValue(*CE->arg_begin()); 320 EmitAggregateAssign(This, RHS, CE->getType()); 321 return RValue::get(This.getPointer(*this)); 322 } 323 324 assert(MD->getParent()->mayInsertExtraPadding() && 325 "unknown trivial member function"); 326 } 327 328 // Compute the function type we're calling. 329 const CXXMethodDecl *CalleeDecl = 330 DevirtualizedMethod ? DevirtualizedMethod : MD; 331 const CGFunctionInfo *FInfo = nullptr; 332 if (const auto *Dtor = dyn_cast<CXXDestructorDecl>(CalleeDecl)) 333 FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration( 334 GlobalDecl(Dtor, Dtor_Complete)); 335 else 336 FInfo = &CGM.getTypes().arrangeCXXMethodDeclaration(CalleeDecl); 337 338 llvm::FunctionType *Ty = CGM.getTypes().GetFunctionType(*FInfo); 339 340 // C++11 [class.mfct.non-static]p2: 341 // If a non-static member function of a class X is called for an object that 342 // is not of type X, or of a type derived from X, the behavior is undefined. 343 SourceLocation CallLoc; 344 ASTContext &C = getContext(); 345 if (CE) 346 CallLoc = CE->getExprLoc(); 347 348 SanitizerSet SkippedChecks; 349 if (const auto *CMCE = dyn_cast<CXXMemberCallExpr>(CE)) { 350 auto *IOA = CMCE->getImplicitObjectArgument(); 351 bool IsImplicitObjectCXXThis = IsWrappedCXXThis(IOA); 352 if (IsImplicitObjectCXXThis) 353 SkippedChecks.set(SanitizerKind::Alignment, true); 354 if (IsImplicitObjectCXXThis || isa<DeclRefExpr>(IOA)) 355 SkippedChecks.set(SanitizerKind::Null, true); 356 } 357 358 if (sanitizePerformTypeCheck()) 359 EmitTypeCheck(CodeGenFunction::TCK_MemberCall, CallLoc, 360 This.emitRawPointer(*this), 361 C.getRecordType(CalleeDecl->getParent()), 362 /*Alignment=*/CharUnits::Zero(), SkippedChecks); 363 364 // C++ [class.virtual]p12: 365 // Explicit qualification with the scope operator (5.1) suppresses the 366 // virtual call mechanism. 367 // 368 // We also don't emit a virtual call if the base expression has a record type 369 // because then we know what the type is. 370 bool UseVirtualCall = CanUseVirtualCall && !DevirtualizedMethod; 371 372 if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(CalleeDecl)) { 373 assert(CE->arg_begin() == CE->arg_end() && 374 "Destructor shouldn't have explicit parameters"); 375 assert(ReturnValue.isNull() && "Destructor shouldn't have return value"); 376 if (UseVirtualCall) { 377 CGM.getCXXABI().EmitVirtualDestructorCall(*this, Dtor, Dtor_Complete, 378 This.getAddress(), 379 cast<CXXMemberCallExpr>(CE)); 380 } else { 381 GlobalDecl GD(Dtor, Dtor_Complete); 382 CGCallee Callee; 383 if (getLangOpts().AppleKext && Dtor->isVirtual() && HasQualifier) 384 Callee = BuildAppleKextVirtualCall(Dtor, Qualifier, Ty); 385 else if (!DevirtualizedMethod) 386 Callee = 387 CGCallee::forDirect(CGM.getAddrOfCXXStructor(GD, FInfo, Ty), GD); 388 else { 389 Callee = CGCallee::forDirect(CGM.GetAddrOfFunction(GD, Ty), GD); 390 } 391 392 QualType ThisTy = 393 IsArrow ? Base->getType()->getPointeeType() : Base->getType(); 394 EmitCXXDestructorCall(GD, Callee, This.getPointer(*this), ThisTy, 395 /*ImplicitParam=*/nullptr, 396 /*ImplicitParamTy=*/QualType(), CE); 397 } 398 return RValue::get(nullptr); 399 } 400 401 // FIXME: Uses of 'MD' past this point need to be audited. We may need to use 402 // 'CalleeDecl' instead. 403 404 CGCallee Callee; 405 if (UseVirtualCall) { 406 Callee = CGCallee::forVirtual(CE, MD, This.getAddress(), Ty); 407 } else { 408 if (SanOpts.has(SanitizerKind::CFINVCall) && 409 MD->getParent()->isDynamicClass()) { 410 llvm::Value *VTable; 411 const CXXRecordDecl *RD; 412 std::tie(VTable, RD) = CGM.getCXXABI().LoadVTablePtr( 413 *this, This.getAddress(), CalleeDecl->getParent()); 414 EmitVTablePtrCheckForCall(RD, VTable, CFITCK_NVCall, CE->getBeginLoc()); 415 } 416 417 if (getLangOpts().AppleKext && MD->isVirtual() && HasQualifier) 418 Callee = BuildAppleKextVirtualCall(MD, Qualifier, Ty); 419 else if (!DevirtualizedMethod) 420 Callee = 421 CGCallee::forDirect(CGM.GetAddrOfFunction(MD, Ty), GlobalDecl(MD)); 422 else { 423 Callee = 424 CGCallee::forDirect(CGM.GetAddrOfFunction(DevirtualizedMethod, Ty), 425 GlobalDecl(DevirtualizedMethod)); 426 } 427 } 428 429 if (MD->isVirtual()) { 430 Address NewThisAddr = 431 CGM.getCXXABI().adjustThisArgumentForVirtualFunctionCall( 432 *this, CalleeDecl, This.getAddress(), UseVirtualCall); 433 This.setAddress(NewThisAddr); 434 } 435 436 return EmitCXXMemberOrOperatorCall( 437 CalleeDecl, Callee, ReturnValue, This.getPointer(*this), 438 /*ImplicitParam=*/nullptr, QualType(), CE, RtlArgs); 439 } 440 441 RValue 442 CodeGenFunction::EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr *E, 443 ReturnValueSlot ReturnValue) { 444 const BinaryOperator *BO = 445 cast<BinaryOperator>(E->getCallee()->IgnoreParens()); 446 const Expr *BaseExpr = BO->getLHS(); 447 const Expr *MemFnExpr = BO->getRHS(); 448 449 const auto *MPT = MemFnExpr->getType()->castAs<MemberPointerType>(); 450 const auto *FPT = MPT->getPointeeType()->castAs<FunctionProtoType>(); 451 const auto *RD = 452 cast<CXXRecordDecl>(MPT->getClass()->castAs<RecordType>()->getDecl()); 453 454 // Emit the 'this' pointer. 455 Address This = Address::invalid(); 456 if (BO->getOpcode() == BO_PtrMemI) 457 This = EmitPointerWithAlignment(BaseExpr, nullptr, nullptr, KnownNonNull); 458 else 459 This = EmitLValue(BaseExpr, KnownNonNull).getAddress(); 460 461 EmitTypeCheck(TCK_MemberCall, E->getExprLoc(), This.emitRawPointer(*this), 462 QualType(MPT->getClass(), 0)); 463 464 // Get the member function pointer. 465 llvm::Value *MemFnPtr = EmitScalarExpr(MemFnExpr); 466 467 // Ask the ABI to load the callee. Note that This is modified. 468 llvm::Value *ThisPtrForCall = nullptr; 469 CGCallee Callee = 470 CGM.getCXXABI().EmitLoadOfMemberFunctionPointer(*this, BO, This, 471 ThisPtrForCall, MemFnPtr, MPT); 472 473 CallArgList Args; 474 475 QualType ThisType = 476 getContext().getPointerType(getContext().getTagDeclType(RD)); 477 478 // Push the this ptr. 479 Args.add(RValue::get(ThisPtrForCall), ThisType); 480 481 RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, 1); 482 483 // And the rest of the call args 484 EmitCallArgs(Args, FPT, E->arguments()); 485 return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required, 486 /*PrefixSize=*/0), 487 Callee, ReturnValue, Args, nullptr, E == MustTailCall, 488 E->getExprLoc()); 489 } 490 491 RValue 492 CodeGenFunction::EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr *E, 493 const CXXMethodDecl *MD, 494 ReturnValueSlot ReturnValue) { 495 assert(MD->isImplicitObjectMemberFunction() && 496 "Trying to emit a member call expr on a static method!"); 497 return EmitCXXMemberOrOperatorMemberCallExpr( 498 E, MD, ReturnValue, /*HasQualifier=*/false, /*Qualifier=*/nullptr, 499 /*IsArrow=*/false, E->getArg(0)); 500 } 501 502 RValue CodeGenFunction::EmitCUDAKernelCallExpr(const CUDAKernelCallExpr *E, 503 ReturnValueSlot ReturnValue) { 504 return CGM.getCUDARuntime().EmitCUDAKernelCallExpr(*this, E, ReturnValue); 505 } 506 507 static void EmitNullBaseClassInitialization(CodeGenFunction &CGF, 508 Address DestPtr, 509 const CXXRecordDecl *Base) { 510 if (Base->isEmpty()) 511 return; 512 513 DestPtr = DestPtr.withElementType(CGF.Int8Ty); 514 515 const ASTRecordLayout &Layout = CGF.getContext().getASTRecordLayout(Base); 516 CharUnits NVSize = Layout.getNonVirtualSize(); 517 518 // We cannot simply zero-initialize the entire base sub-object if vbptrs are 519 // present, they are initialized by the most derived class before calling the 520 // constructor. 521 SmallVector<std::pair<CharUnits, CharUnits>, 1> Stores; 522 Stores.emplace_back(CharUnits::Zero(), NVSize); 523 524 // Each store is split by the existence of a vbptr. 525 CharUnits VBPtrWidth = CGF.getPointerSize(); 526 std::vector<CharUnits> VBPtrOffsets = 527 CGF.CGM.getCXXABI().getVBPtrOffsets(Base); 528 for (CharUnits VBPtrOffset : VBPtrOffsets) { 529 // Stop before we hit any virtual base pointers located in virtual bases. 530 if (VBPtrOffset >= NVSize) 531 break; 532 std::pair<CharUnits, CharUnits> LastStore = Stores.pop_back_val(); 533 CharUnits LastStoreOffset = LastStore.first; 534 CharUnits LastStoreSize = LastStore.second; 535 536 CharUnits SplitBeforeOffset = LastStoreOffset; 537 CharUnits SplitBeforeSize = VBPtrOffset - SplitBeforeOffset; 538 assert(!SplitBeforeSize.isNegative() && "negative store size!"); 539 if (!SplitBeforeSize.isZero()) 540 Stores.emplace_back(SplitBeforeOffset, SplitBeforeSize); 541 542 CharUnits SplitAfterOffset = VBPtrOffset + VBPtrWidth; 543 CharUnits SplitAfterSize = LastStoreSize - SplitAfterOffset; 544 assert(!SplitAfterSize.isNegative() && "negative store size!"); 545 if (!SplitAfterSize.isZero()) 546 Stores.emplace_back(SplitAfterOffset, SplitAfterSize); 547 } 548 549 // If the type contains a pointer to data member we can't memset it to zero. 550 // Instead, create a null constant and copy it to the destination. 551 // TODO: there are other patterns besides zero that we can usefully memset, 552 // like -1, which happens to be the pattern used by member-pointers. 553 // TODO: isZeroInitializable can be over-conservative in the case where a 554 // virtual base contains a member pointer. 555 llvm::Constant *NullConstantForBase = CGF.CGM.EmitNullConstantForBase(Base); 556 if (!NullConstantForBase->isNullValue()) { 557 llvm::GlobalVariable *NullVariable = new llvm::GlobalVariable( 558 CGF.CGM.getModule(), NullConstantForBase->getType(), 559 /*isConstant=*/true, llvm::GlobalVariable::PrivateLinkage, 560 NullConstantForBase, Twine()); 561 562 CharUnits Align = 563 std::max(Layout.getNonVirtualAlignment(), DestPtr.getAlignment()); 564 NullVariable->setAlignment(Align.getAsAlign()); 565 566 Address SrcPtr(NullVariable, CGF.Int8Ty, Align); 567 568 // Get and call the appropriate llvm.memcpy overload. 569 for (std::pair<CharUnits, CharUnits> Store : Stores) { 570 CharUnits StoreOffset = Store.first; 571 CharUnits StoreSize = Store.second; 572 llvm::Value *StoreSizeVal = CGF.CGM.getSize(StoreSize); 573 CGF.Builder.CreateMemCpy( 574 CGF.Builder.CreateConstInBoundsByteGEP(DestPtr, StoreOffset), 575 CGF.Builder.CreateConstInBoundsByteGEP(SrcPtr, StoreOffset), 576 StoreSizeVal); 577 } 578 579 // Otherwise, just memset the whole thing to zero. This is legal 580 // because in LLVM, all default initializers (other than the ones we just 581 // handled above) are guaranteed to have a bit pattern of all zeros. 582 } else { 583 for (std::pair<CharUnits, CharUnits> Store : Stores) { 584 CharUnits StoreOffset = Store.first; 585 CharUnits StoreSize = Store.second; 586 llvm::Value *StoreSizeVal = CGF.CGM.getSize(StoreSize); 587 CGF.Builder.CreateMemSet( 588 CGF.Builder.CreateConstInBoundsByteGEP(DestPtr, StoreOffset), 589 CGF.Builder.getInt8(0), StoreSizeVal); 590 } 591 } 592 } 593 594 void 595 CodeGenFunction::EmitCXXConstructExpr(const CXXConstructExpr *E, 596 AggValueSlot Dest) { 597 assert(!Dest.isIgnored() && "Must have a destination!"); 598 const CXXConstructorDecl *CD = E->getConstructor(); 599 600 // If we require zero initialization before (or instead of) calling the 601 // constructor, as can be the case with a non-user-provided default 602 // constructor, emit the zero initialization now, unless destination is 603 // already zeroed. 604 if (E->requiresZeroInitialization() && !Dest.isZeroed()) { 605 switch (E->getConstructionKind()) { 606 case CXXConstructionKind::Delegating: 607 case CXXConstructionKind::Complete: 608 EmitNullInitialization(Dest.getAddress(), E->getType()); 609 break; 610 case CXXConstructionKind::VirtualBase: 611 case CXXConstructionKind::NonVirtualBase: 612 EmitNullBaseClassInitialization(*this, Dest.getAddress(), 613 CD->getParent()); 614 break; 615 } 616 } 617 618 // If this is a call to a trivial default constructor, do nothing. 619 if (CD->isTrivial() && CD->isDefaultConstructor()) 620 return; 621 622 // Elide the constructor if we're constructing from a temporary. 623 if (getLangOpts().ElideConstructors && E->isElidable()) { 624 // FIXME: This only handles the simplest case, where the source object 625 // is passed directly as the first argument to the constructor. 626 // This should also handle stepping though implicit casts and 627 // conversion sequences which involve two steps, with a 628 // conversion operator followed by a converting constructor. 629 const Expr *SrcObj = E->getArg(0); 630 assert(SrcObj->isTemporaryObject(getContext(), CD->getParent())); 631 assert( 632 getContext().hasSameUnqualifiedType(E->getType(), SrcObj->getType())); 633 EmitAggExpr(SrcObj, Dest); 634 return; 635 } 636 637 if (const ArrayType *arrayType 638 = getContext().getAsArrayType(E->getType())) { 639 EmitCXXAggrConstructorCall(CD, arrayType, Dest.getAddress(), E, 640 Dest.isSanitizerChecked()); 641 } else { 642 CXXCtorType Type = Ctor_Complete; 643 bool ForVirtualBase = false; 644 bool Delegating = false; 645 646 switch (E->getConstructionKind()) { 647 case CXXConstructionKind::Delegating: 648 // We should be emitting a constructor; GlobalDecl will assert this 649 Type = CurGD.getCtorType(); 650 Delegating = true; 651 break; 652 653 case CXXConstructionKind::Complete: 654 Type = Ctor_Complete; 655 break; 656 657 case CXXConstructionKind::VirtualBase: 658 ForVirtualBase = true; 659 [[fallthrough]]; 660 661 case CXXConstructionKind::NonVirtualBase: 662 Type = Ctor_Base; 663 } 664 665 // Call the constructor. 666 EmitCXXConstructorCall(CD, Type, ForVirtualBase, Delegating, Dest, E); 667 } 668 } 669 670 void CodeGenFunction::EmitSynthesizedCXXCopyCtor(Address Dest, Address Src, 671 const Expr *Exp) { 672 if (const ExprWithCleanups *E = dyn_cast<ExprWithCleanups>(Exp)) 673 Exp = E->getSubExpr(); 674 assert(isa<CXXConstructExpr>(Exp) && 675 "EmitSynthesizedCXXCopyCtor - unknown copy ctor expr"); 676 const CXXConstructExpr* E = cast<CXXConstructExpr>(Exp); 677 const CXXConstructorDecl *CD = E->getConstructor(); 678 RunCleanupsScope Scope(*this); 679 680 // If we require zero initialization before (or instead of) calling the 681 // constructor, as can be the case with a non-user-provided default 682 // constructor, emit the zero initialization now. 683 // FIXME. Do I still need this for a copy ctor synthesis? 684 if (E->requiresZeroInitialization()) 685 EmitNullInitialization(Dest, E->getType()); 686 687 assert(!getContext().getAsConstantArrayType(E->getType()) 688 && "EmitSynthesizedCXXCopyCtor - Copied-in Array"); 689 EmitSynthesizedCXXCopyCtorCall(CD, Dest, Src, E); 690 } 691 692 static CharUnits CalculateCookiePadding(CodeGenFunction &CGF, 693 const CXXNewExpr *E) { 694 if (!E->isArray()) 695 return CharUnits::Zero(); 696 697 // No cookie is required if the operator new[] being used is the 698 // reserved placement operator new[]. 699 if (E->getOperatorNew()->isReservedGlobalPlacementOperator()) 700 return CharUnits::Zero(); 701 702 return CGF.CGM.getCXXABI().GetArrayCookieSize(E); 703 } 704 705 static llvm::Value *EmitCXXNewAllocSize(CodeGenFunction &CGF, 706 const CXXNewExpr *e, 707 unsigned minElements, 708 llvm::Value *&numElements, 709 llvm::Value *&sizeWithoutCookie) { 710 QualType type = e->getAllocatedType(); 711 712 if (!e->isArray()) { 713 CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type); 714 sizeWithoutCookie 715 = llvm::ConstantInt::get(CGF.SizeTy, typeSize.getQuantity()); 716 return sizeWithoutCookie; 717 } 718 719 // The width of size_t. 720 unsigned sizeWidth = CGF.SizeTy->getBitWidth(); 721 722 // Figure out the cookie size. 723 llvm::APInt cookieSize(sizeWidth, 724 CalculateCookiePadding(CGF, e).getQuantity()); 725 726 // Emit the array size expression. 727 // We multiply the size of all dimensions for NumElements. 728 // e.g for 'int[2][3]', ElemType is 'int' and NumElements is 6. 729 numElements = 730 ConstantEmitter(CGF).tryEmitAbstract(*e->getArraySize(), e->getType()); 731 if (!numElements) 732 numElements = CGF.EmitScalarExpr(*e->getArraySize()); 733 assert(isa<llvm::IntegerType>(numElements->getType())); 734 735 // The number of elements can be have an arbitrary integer type; 736 // essentially, we need to multiply it by a constant factor, add a 737 // cookie size, and verify that the result is representable as a 738 // size_t. That's just a gloss, though, and it's wrong in one 739 // important way: if the count is negative, it's an error even if 740 // the cookie size would bring the total size >= 0. 741 bool isSigned 742 = (*e->getArraySize())->getType()->isSignedIntegerOrEnumerationType(); 743 llvm::IntegerType *numElementsType 744 = cast<llvm::IntegerType>(numElements->getType()); 745 unsigned numElementsWidth = numElementsType->getBitWidth(); 746 747 // Compute the constant factor. 748 llvm::APInt arraySizeMultiplier(sizeWidth, 1); 749 while (const ConstantArrayType *CAT 750 = CGF.getContext().getAsConstantArrayType(type)) { 751 type = CAT->getElementType(); 752 arraySizeMultiplier *= CAT->getSize(); 753 } 754 755 CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type); 756 llvm::APInt typeSizeMultiplier(sizeWidth, typeSize.getQuantity()); 757 typeSizeMultiplier *= arraySizeMultiplier; 758 759 // This will be a size_t. 760 llvm::Value *size; 761 762 // If someone is doing 'new int[42]' there is no need to do a dynamic check. 763 // Don't bloat the -O0 code. 764 if (llvm::ConstantInt *numElementsC = 765 dyn_cast<llvm::ConstantInt>(numElements)) { 766 const llvm::APInt &count = numElementsC->getValue(); 767 768 bool hasAnyOverflow = false; 769 770 // If 'count' was a negative number, it's an overflow. 771 if (isSigned && count.isNegative()) 772 hasAnyOverflow = true; 773 774 // We want to do all this arithmetic in size_t. If numElements is 775 // wider than that, check whether it's already too big, and if so, 776 // overflow. 777 else if (numElementsWidth > sizeWidth && 778 numElementsWidth - sizeWidth > count.countl_zero()) 779 hasAnyOverflow = true; 780 781 // Okay, compute a count at the right width. 782 llvm::APInt adjustedCount = count.zextOrTrunc(sizeWidth); 783 784 // If there is a brace-initializer, we cannot allocate fewer elements than 785 // there are initializers. If we do, that's treated like an overflow. 786 if (adjustedCount.ult(minElements)) 787 hasAnyOverflow = true; 788 789 // Scale numElements by that. This might overflow, but we don't 790 // care because it only overflows if allocationSize does, too, and 791 // if that overflows then we shouldn't use this. 792 numElements = llvm::ConstantInt::get(CGF.SizeTy, 793 adjustedCount * arraySizeMultiplier); 794 795 // Compute the size before cookie, and track whether it overflowed. 796 bool overflow; 797 llvm::APInt allocationSize 798 = adjustedCount.umul_ov(typeSizeMultiplier, overflow); 799 hasAnyOverflow |= overflow; 800 801 // Add in the cookie, and check whether it's overflowed. 802 if (cookieSize != 0) { 803 // Save the current size without a cookie. This shouldn't be 804 // used if there was overflow. 805 sizeWithoutCookie = llvm::ConstantInt::get(CGF.SizeTy, allocationSize); 806 807 allocationSize = allocationSize.uadd_ov(cookieSize, overflow); 808 hasAnyOverflow |= overflow; 809 } 810 811 // On overflow, produce a -1 so operator new will fail. 812 if (hasAnyOverflow) { 813 size = llvm::Constant::getAllOnesValue(CGF.SizeTy); 814 } else { 815 size = llvm::ConstantInt::get(CGF.SizeTy, allocationSize); 816 } 817 818 // Otherwise, we might need to use the overflow intrinsics. 819 } else { 820 // There are up to five conditions we need to test for: 821 // 1) if isSigned, we need to check whether numElements is negative; 822 // 2) if numElementsWidth > sizeWidth, we need to check whether 823 // numElements is larger than something representable in size_t; 824 // 3) if minElements > 0, we need to check whether numElements is smaller 825 // than that. 826 // 4) we need to compute 827 // sizeWithoutCookie := numElements * typeSizeMultiplier 828 // and check whether it overflows; and 829 // 5) if we need a cookie, we need to compute 830 // size := sizeWithoutCookie + cookieSize 831 // and check whether it overflows. 832 833 llvm::Value *hasOverflow = nullptr; 834 835 // If numElementsWidth > sizeWidth, then one way or another, we're 836 // going to have to do a comparison for (2), and this happens to 837 // take care of (1), too. 838 if (numElementsWidth > sizeWidth) { 839 llvm::APInt threshold = 840 llvm::APInt::getOneBitSet(numElementsWidth, sizeWidth); 841 842 llvm::Value *thresholdV 843 = llvm::ConstantInt::get(numElementsType, threshold); 844 845 hasOverflow = CGF.Builder.CreateICmpUGE(numElements, thresholdV); 846 numElements = CGF.Builder.CreateTrunc(numElements, CGF.SizeTy); 847 848 // Otherwise, if we're signed, we want to sext up to size_t. 849 } else if (isSigned) { 850 if (numElementsWidth < sizeWidth) 851 numElements = CGF.Builder.CreateSExt(numElements, CGF.SizeTy); 852 853 // If there's a non-1 type size multiplier, then we can do the 854 // signedness check at the same time as we do the multiply 855 // because a negative number times anything will cause an 856 // unsigned overflow. Otherwise, we have to do it here. But at least 857 // in this case, we can subsume the >= minElements check. 858 if (typeSizeMultiplier == 1) 859 hasOverflow = CGF.Builder.CreateICmpSLT(numElements, 860 llvm::ConstantInt::get(CGF.SizeTy, minElements)); 861 862 // Otherwise, zext up to size_t if necessary. 863 } else if (numElementsWidth < sizeWidth) { 864 numElements = CGF.Builder.CreateZExt(numElements, CGF.SizeTy); 865 } 866 867 assert(numElements->getType() == CGF.SizeTy); 868 869 if (minElements) { 870 // Don't allow allocation of fewer elements than we have initializers. 871 if (!hasOverflow) { 872 hasOverflow = CGF.Builder.CreateICmpULT(numElements, 873 llvm::ConstantInt::get(CGF.SizeTy, minElements)); 874 } else if (numElementsWidth > sizeWidth) { 875 // The other existing overflow subsumes this check. 876 // We do an unsigned comparison, since any signed value < -1 is 877 // taken care of either above or below. 878 hasOverflow = CGF.Builder.CreateOr(hasOverflow, 879 CGF.Builder.CreateICmpULT(numElements, 880 llvm::ConstantInt::get(CGF.SizeTy, minElements))); 881 } 882 } 883 884 size = numElements; 885 886 // Multiply by the type size if necessary. This multiplier 887 // includes all the factors for nested arrays. 888 // 889 // This step also causes numElements to be scaled up by the 890 // nested-array factor if necessary. Overflow on this computation 891 // can be ignored because the result shouldn't be used if 892 // allocation fails. 893 if (typeSizeMultiplier != 1) { 894 llvm::Function *umul_with_overflow 895 = CGF.CGM.getIntrinsic(llvm::Intrinsic::umul_with_overflow, CGF.SizeTy); 896 897 llvm::Value *tsmV = 898 llvm::ConstantInt::get(CGF.SizeTy, typeSizeMultiplier); 899 llvm::Value *result = 900 CGF.Builder.CreateCall(umul_with_overflow, {size, tsmV}); 901 902 llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1); 903 if (hasOverflow) 904 hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed); 905 else 906 hasOverflow = overflowed; 907 908 size = CGF.Builder.CreateExtractValue(result, 0); 909 910 // Also scale up numElements by the array size multiplier. 911 if (arraySizeMultiplier != 1) { 912 // If the base element type size is 1, then we can re-use the 913 // multiply we just did. 914 if (typeSize.isOne()) { 915 assert(arraySizeMultiplier == typeSizeMultiplier); 916 numElements = size; 917 918 // Otherwise we need a separate multiply. 919 } else { 920 llvm::Value *asmV = 921 llvm::ConstantInt::get(CGF.SizeTy, arraySizeMultiplier); 922 numElements = CGF.Builder.CreateMul(numElements, asmV); 923 } 924 } 925 } else { 926 // numElements doesn't need to be scaled. 927 assert(arraySizeMultiplier == 1); 928 } 929 930 // Add in the cookie size if necessary. 931 if (cookieSize != 0) { 932 sizeWithoutCookie = size; 933 934 llvm::Function *uadd_with_overflow 935 = CGF.CGM.getIntrinsic(llvm::Intrinsic::uadd_with_overflow, CGF.SizeTy); 936 937 llvm::Value *cookieSizeV = llvm::ConstantInt::get(CGF.SizeTy, cookieSize); 938 llvm::Value *result = 939 CGF.Builder.CreateCall(uadd_with_overflow, {size, cookieSizeV}); 940 941 llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1); 942 if (hasOverflow) 943 hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed); 944 else 945 hasOverflow = overflowed; 946 947 size = CGF.Builder.CreateExtractValue(result, 0); 948 } 949 950 // If we had any possibility of dynamic overflow, make a select to 951 // overwrite 'size' with an all-ones value, which should cause 952 // operator new to throw. 953 if (hasOverflow) 954 size = CGF.Builder.CreateSelect(hasOverflow, 955 llvm::Constant::getAllOnesValue(CGF.SizeTy), 956 size); 957 } 958 959 if (cookieSize == 0) 960 sizeWithoutCookie = size; 961 else 962 assert(sizeWithoutCookie && "didn't set sizeWithoutCookie?"); 963 964 return size; 965 } 966 967 static void StoreAnyExprIntoOneUnit(CodeGenFunction &CGF, const Expr *Init, 968 QualType AllocType, Address NewPtr, 969 AggValueSlot::Overlap_t MayOverlap) { 970 // FIXME: Refactor with EmitExprAsInit. 971 switch (CGF.getEvaluationKind(AllocType)) { 972 case TEK_Scalar: 973 CGF.EmitScalarInit(Init, nullptr, 974 CGF.MakeAddrLValue(NewPtr, AllocType), false); 975 return; 976 case TEK_Complex: 977 CGF.EmitComplexExprIntoLValue(Init, CGF.MakeAddrLValue(NewPtr, AllocType), 978 /*isInit*/ true); 979 return; 980 case TEK_Aggregate: { 981 AggValueSlot Slot 982 = AggValueSlot::forAddr(NewPtr, AllocType.getQualifiers(), 983 AggValueSlot::IsDestructed, 984 AggValueSlot::DoesNotNeedGCBarriers, 985 AggValueSlot::IsNotAliased, 986 MayOverlap, AggValueSlot::IsNotZeroed, 987 AggValueSlot::IsSanitizerChecked); 988 CGF.EmitAggExpr(Init, Slot); 989 return; 990 } 991 } 992 llvm_unreachable("bad evaluation kind"); 993 } 994 995 void CodeGenFunction::EmitNewArrayInitializer( 996 const CXXNewExpr *E, QualType ElementType, llvm::Type *ElementTy, 997 Address BeginPtr, llvm::Value *NumElements, 998 llvm::Value *AllocSizeWithoutCookie) { 999 // If we have a type with trivial initialization and no initializer, 1000 // there's nothing to do. 1001 if (!E->hasInitializer()) 1002 return; 1003 1004 Address CurPtr = BeginPtr; 1005 1006 unsigned InitListElements = 0; 1007 1008 const Expr *Init = E->getInitializer(); 1009 Address EndOfInit = Address::invalid(); 1010 QualType::DestructionKind DtorKind = ElementType.isDestructedType(); 1011 CleanupDeactivationScope deactivation(*this); 1012 bool pushedCleanup = false; 1013 1014 CharUnits ElementSize = getContext().getTypeSizeInChars(ElementType); 1015 CharUnits ElementAlign = 1016 BeginPtr.getAlignment().alignmentOfArrayElement(ElementSize); 1017 1018 // Attempt to perform zero-initialization using memset. 1019 auto TryMemsetInitialization = [&]() -> bool { 1020 // FIXME: If the type is a pointer-to-data-member under the Itanium ABI, 1021 // we can initialize with a memset to -1. 1022 if (!CGM.getTypes().isZeroInitializable(ElementType)) 1023 return false; 1024 1025 // Optimization: since zero initialization will just set the memory 1026 // to all zeroes, generate a single memset to do it in one shot. 1027 1028 // Subtract out the size of any elements we've already initialized. 1029 auto *RemainingSize = AllocSizeWithoutCookie; 1030 if (InitListElements) { 1031 // We know this can't overflow; we check this when doing the allocation. 1032 auto *InitializedSize = llvm::ConstantInt::get( 1033 RemainingSize->getType(), 1034 getContext().getTypeSizeInChars(ElementType).getQuantity() * 1035 InitListElements); 1036 RemainingSize = Builder.CreateSub(RemainingSize, InitializedSize); 1037 } 1038 1039 // Create the memset. 1040 Builder.CreateMemSet(CurPtr, Builder.getInt8(0), RemainingSize, false); 1041 return true; 1042 }; 1043 1044 const InitListExpr *ILE = dyn_cast<InitListExpr>(Init); 1045 const CXXParenListInitExpr *CPLIE = nullptr; 1046 const StringLiteral *SL = nullptr; 1047 const ObjCEncodeExpr *OCEE = nullptr; 1048 const Expr *IgnoreParen = nullptr; 1049 if (!ILE) { 1050 IgnoreParen = Init->IgnoreParenImpCasts(); 1051 CPLIE = dyn_cast<CXXParenListInitExpr>(IgnoreParen); 1052 SL = dyn_cast<StringLiteral>(IgnoreParen); 1053 OCEE = dyn_cast<ObjCEncodeExpr>(IgnoreParen); 1054 } 1055 1056 // If the initializer is an initializer list, first do the explicit elements. 1057 if (ILE || CPLIE || SL || OCEE) { 1058 // Initializing from a (braced) string literal is a special case; the init 1059 // list element does not initialize a (single) array element. 1060 if ((ILE && ILE->isStringLiteralInit()) || SL || OCEE) { 1061 if (!ILE) 1062 Init = IgnoreParen; 1063 // Initialize the initial portion of length equal to that of the string 1064 // literal. The allocation must be for at least this much; we emitted a 1065 // check for that earlier. 1066 AggValueSlot Slot = 1067 AggValueSlot::forAddr(CurPtr, ElementType.getQualifiers(), 1068 AggValueSlot::IsDestructed, 1069 AggValueSlot::DoesNotNeedGCBarriers, 1070 AggValueSlot::IsNotAliased, 1071 AggValueSlot::DoesNotOverlap, 1072 AggValueSlot::IsNotZeroed, 1073 AggValueSlot::IsSanitizerChecked); 1074 EmitAggExpr(ILE ? ILE->getInit(0) : Init, Slot); 1075 1076 // Move past these elements. 1077 InitListElements = 1078 cast<ConstantArrayType>(Init->getType()->getAsArrayTypeUnsafe()) 1079 ->getZExtSize(); 1080 CurPtr = Builder.CreateConstInBoundsGEP( 1081 CurPtr, InitListElements, "string.init.end"); 1082 1083 // Zero out the rest, if any remain. 1084 llvm::ConstantInt *ConstNum = dyn_cast<llvm::ConstantInt>(NumElements); 1085 if (!ConstNum || !ConstNum->equalsInt(InitListElements)) { 1086 bool OK = TryMemsetInitialization(); 1087 (void)OK; 1088 assert(OK && "couldn't memset character type?"); 1089 } 1090 return; 1091 } 1092 1093 ArrayRef<const Expr *> InitExprs = 1094 ILE ? ILE->inits() : CPLIE->getInitExprs(); 1095 InitListElements = InitExprs.size(); 1096 1097 // If this is a multi-dimensional array new, we will initialize multiple 1098 // elements with each init list element. 1099 QualType AllocType = E->getAllocatedType(); 1100 if (const ConstantArrayType *CAT = dyn_cast_or_null<ConstantArrayType>( 1101 AllocType->getAsArrayTypeUnsafe())) { 1102 ElementTy = ConvertTypeForMem(AllocType); 1103 CurPtr = CurPtr.withElementType(ElementTy); 1104 InitListElements *= getContext().getConstantArrayElementCount(CAT); 1105 } 1106 1107 // Enter a partial-destruction Cleanup if necessary. 1108 if (DtorKind) { 1109 AllocaTrackerRAII AllocaTracker(*this); 1110 // In principle we could tell the Cleanup where we are more 1111 // directly, but the control flow can get so varied here that it 1112 // would actually be quite complex. Therefore we go through an 1113 // alloca. 1114 llvm::Instruction *DominatingIP = 1115 Builder.CreateFlagLoad(llvm::ConstantInt::getNullValue(Int8PtrTy)); 1116 EndOfInit = CreateTempAlloca(BeginPtr.getType(), getPointerAlign(), 1117 "array.init.end"); 1118 pushIrregularPartialArrayCleanup(BeginPtr.emitRawPointer(*this), 1119 EndOfInit, ElementType, ElementAlign, 1120 getDestroyer(DtorKind)); 1121 cast<EHCleanupScope>(*EHStack.find(EHStack.stable_begin())) 1122 .AddAuxAllocas(AllocaTracker.Take()); 1123 DeferredDeactivationCleanupStack.push_back( 1124 {EHStack.stable_begin(), DominatingIP}); 1125 pushedCleanup = true; 1126 } 1127 1128 CharUnits StartAlign = CurPtr.getAlignment(); 1129 unsigned i = 0; 1130 for (const Expr *IE : InitExprs) { 1131 // Tell the cleanup that it needs to destroy up to this 1132 // element. TODO: some of these stores can be trivially 1133 // observed to be unnecessary. 1134 if (EndOfInit.isValid()) { 1135 Builder.CreateStore(CurPtr.emitRawPointer(*this), EndOfInit); 1136 } 1137 // FIXME: If the last initializer is an incomplete initializer list for 1138 // an array, and we have an array filler, we can fold together the two 1139 // initialization loops. 1140 StoreAnyExprIntoOneUnit(*this, IE, IE->getType(), CurPtr, 1141 AggValueSlot::DoesNotOverlap); 1142 CurPtr = Address(Builder.CreateInBoundsGEP(CurPtr.getElementType(), 1143 CurPtr.emitRawPointer(*this), 1144 Builder.getSize(1), 1145 "array.exp.next"), 1146 CurPtr.getElementType(), 1147 StartAlign.alignmentAtOffset((++i) * ElementSize)); 1148 } 1149 1150 // The remaining elements are filled with the array filler expression. 1151 Init = ILE ? ILE->getArrayFiller() : CPLIE->getArrayFiller(); 1152 1153 // Extract the initializer for the individual array elements by pulling 1154 // out the array filler from all the nested initializer lists. This avoids 1155 // generating a nested loop for the initialization. 1156 while (Init && Init->getType()->isConstantArrayType()) { 1157 auto *SubILE = dyn_cast<InitListExpr>(Init); 1158 if (!SubILE) 1159 break; 1160 assert(SubILE->getNumInits() == 0 && "explicit inits in array filler?"); 1161 Init = SubILE->getArrayFiller(); 1162 } 1163 1164 // Switch back to initializing one base element at a time. 1165 CurPtr = CurPtr.withElementType(BeginPtr.getElementType()); 1166 } 1167 1168 // If all elements have already been initialized, skip any further 1169 // initialization. 1170 llvm::ConstantInt *ConstNum = dyn_cast<llvm::ConstantInt>(NumElements); 1171 if (ConstNum && ConstNum->getZExtValue() <= InitListElements) { 1172 return; 1173 } 1174 1175 assert(Init && "have trailing elements to initialize but no initializer"); 1176 1177 // If this is a constructor call, try to optimize it out, and failing that 1178 // emit a single loop to initialize all remaining elements. 1179 if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(Init)) { 1180 CXXConstructorDecl *Ctor = CCE->getConstructor(); 1181 if (Ctor->isTrivial()) { 1182 // If new expression did not specify value-initialization, then there 1183 // is no initialization. 1184 if (!CCE->requiresZeroInitialization() || Ctor->getParent()->isEmpty()) 1185 return; 1186 1187 if (TryMemsetInitialization()) 1188 return; 1189 } 1190 1191 // Store the new Cleanup position for irregular Cleanups. 1192 // 1193 // FIXME: Share this cleanup with the constructor call emission rather than 1194 // having it create a cleanup of its own. 1195 if (EndOfInit.isValid()) 1196 Builder.CreateStore(CurPtr.emitRawPointer(*this), EndOfInit); 1197 1198 // Emit a constructor call loop to initialize the remaining elements. 1199 if (InitListElements) 1200 NumElements = Builder.CreateSub( 1201 NumElements, 1202 llvm::ConstantInt::get(NumElements->getType(), InitListElements)); 1203 EmitCXXAggrConstructorCall(Ctor, NumElements, CurPtr, CCE, 1204 /*NewPointerIsChecked*/true, 1205 CCE->requiresZeroInitialization()); 1206 return; 1207 } 1208 1209 // If this is value-initialization, we can usually use memset. 1210 ImplicitValueInitExpr IVIE(ElementType); 1211 if (isa<ImplicitValueInitExpr>(Init)) { 1212 if (TryMemsetInitialization()) 1213 return; 1214 1215 // Switch to an ImplicitValueInitExpr for the element type. This handles 1216 // only one case: multidimensional array new of pointers to members. In 1217 // all other cases, we already have an initializer for the array element. 1218 Init = &IVIE; 1219 } 1220 1221 // At this point we should have found an initializer for the individual 1222 // elements of the array. 1223 assert(getContext().hasSameUnqualifiedType(ElementType, Init->getType()) && 1224 "got wrong type of element to initialize"); 1225 1226 // If we have an empty initializer list, we can usually use memset. 1227 if (auto *ILE = dyn_cast<InitListExpr>(Init)) 1228 if (ILE->getNumInits() == 0 && TryMemsetInitialization()) 1229 return; 1230 1231 // If we have a struct whose every field is value-initialized, we can 1232 // usually use memset. 1233 if (auto *ILE = dyn_cast<InitListExpr>(Init)) { 1234 if (const RecordType *RType = ILE->getType()->getAs<RecordType>()) { 1235 if (RType->getDecl()->isStruct()) { 1236 unsigned NumElements = 0; 1237 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RType->getDecl())) 1238 NumElements = CXXRD->getNumBases(); 1239 for (auto *Field : RType->getDecl()->fields()) 1240 if (!Field->isUnnamedBitField()) 1241 ++NumElements; 1242 // FIXME: Recurse into nested InitListExprs. 1243 if (ILE->getNumInits() == NumElements) 1244 for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i) 1245 if (!isa<ImplicitValueInitExpr>(ILE->getInit(i))) 1246 --NumElements; 1247 if (ILE->getNumInits() == NumElements && TryMemsetInitialization()) 1248 return; 1249 } 1250 } 1251 } 1252 1253 // Create the loop blocks. 1254 llvm::BasicBlock *EntryBB = Builder.GetInsertBlock(); 1255 llvm::BasicBlock *LoopBB = createBasicBlock("new.loop"); 1256 llvm::BasicBlock *ContBB = createBasicBlock("new.loop.end"); 1257 1258 // Find the end of the array, hoisted out of the loop. 1259 llvm::Value *EndPtr = Builder.CreateInBoundsGEP( 1260 BeginPtr.getElementType(), BeginPtr.emitRawPointer(*this), NumElements, 1261 "array.end"); 1262 1263 // If the number of elements isn't constant, we have to now check if there is 1264 // anything left to initialize. 1265 if (!ConstNum) { 1266 llvm::Value *IsEmpty = Builder.CreateICmpEQ(CurPtr.emitRawPointer(*this), 1267 EndPtr, "array.isempty"); 1268 Builder.CreateCondBr(IsEmpty, ContBB, LoopBB); 1269 } 1270 1271 // Enter the loop. 1272 EmitBlock(LoopBB); 1273 1274 // Set up the current-element phi. 1275 llvm::PHINode *CurPtrPhi = 1276 Builder.CreatePHI(CurPtr.getType(), 2, "array.cur"); 1277 CurPtrPhi->addIncoming(CurPtr.emitRawPointer(*this), EntryBB); 1278 1279 CurPtr = Address(CurPtrPhi, CurPtr.getElementType(), ElementAlign); 1280 1281 // Store the new Cleanup position for irregular Cleanups. 1282 if (EndOfInit.isValid()) 1283 Builder.CreateStore(CurPtr.emitRawPointer(*this), EndOfInit); 1284 1285 // Enter a partial-destruction Cleanup if necessary. 1286 if (!pushedCleanup && needsEHCleanup(DtorKind)) { 1287 llvm::Instruction *DominatingIP = 1288 Builder.CreateFlagLoad(llvm::ConstantInt::getNullValue(Int8PtrTy)); 1289 pushRegularPartialArrayCleanup(BeginPtr.emitRawPointer(*this), 1290 CurPtr.emitRawPointer(*this), ElementType, 1291 ElementAlign, getDestroyer(DtorKind)); 1292 DeferredDeactivationCleanupStack.push_back( 1293 {EHStack.stable_begin(), DominatingIP}); 1294 } 1295 1296 // Emit the initializer into this element. 1297 StoreAnyExprIntoOneUnit(*this, Init, Init->getType(), CurPtr, 1298 AggValueSlot::DoesNotOverlap); 1299 1300 // Leave the Cleanup if we entered one. 1301 deactivation.ForceDeactivate(); 1302 1303 // Advance to the next element by adjusting the pointer type as necessary. 1304 llvm::Value *NextPtr = Builder.CreateConstInBoundsGEP1_32( 1305 ElementTy, CurPtr.emitRawPointer(*this), 1, "array.next"); 1306 1307 // Check whether we've gotten to the end of the array and, if so, 1308 // exit the loop. 1309 llvm::Value *IsEnd = Builder.CreateICmpEQ(NextPtr, EndPtr, "array.atend"); 1310 Builder.CreateCondBr(IsEnd, ContBB, LoopBB); 1311 CurPtrPhi->addIncoming(NextPtr, Builder.GetInsertBlock()); 1312 1313 EmitBlock(ContBB); 1314 } 1315 1316 static void EmitNewInitializer(CodeGenFunction &CGF, const CXXNewExpr *E, 1317 QualType ElementType, llvm::Type *ElementTy, 1318 Address NewPtr, llvm::Value *NumElements, 1319 llvm::Value *AllocSizeWithoutCookie) { 1320 ApplyDebugLocation DL(CGF, E); 1321 if (E->isArray()) 1322 CGF.EmitNewArrayInitializer(E, ElementType, ElementTy, NewPtr, NumElements, 1323 AllocSizeWithoutCookie); 1324 else if (const Expr *Init = E->getInitializer()) 1325 StoreAnyExprIntoOneUnit(CGF, Init, E->getAllocatedType(), NewPtr, 1326 AggValueSlot::DoesNotOverlap); 1327 } 1328 1329 /// Emit a call to an operator new or operator delete function, as implicitly 1330 /// created by new-expressions and delete-expressions. 1331 static RValue EmitNewDeleteCall(CodeGenFunction &CGF, 1332 const FunctionDecl *CalleeDecl, 1333 const FunctionProtoType *CalleeType, 1334 const CallArgList &Args) { 1335 llvm::CallBase *CallOrInvoke; 1336 llvm::Constant *CalleePtr = CGF.CGM.GetAddrOfFunction(CalleeDecl); 1337 CGCallee Callee = CGCallee::forDirect(CalleePtr, GlobalDecl(CalleeDecl)); 1338 RValue RV = 1339 CGF.EmitCall(CGF.CGM.getTypes().arrangeFreeFunctionCall( 1340 Args, CalleeType, /*ChainCall=*/false), 1341 Callee, ReturnValueSlot(), Args, &CallOrInvoke); 1342 1343 /// C++1y [expr.new]p10: 1344 /// [In a new-expression,] an implementation is allowed to omit a call 1345 /// to a replaceable global allocation function. 1346 /// 1347 /// We model such elidable calls with the 'builtin' attribute. 1348 llvm::Function *Fn = dyn_cast<llvm::Function>(CalleePtr); 1349 if (CalleeDecl->isReplaceableGlobalAllocationFunction() && 1350 Fn && Fn->hasFnAttribute(llvm::Attribute::NoBuiltin)) { 1351 CallOrInvoke->addFnAttr(llvm::Attribute::Builtin); 1352 } 1353 1354 return RV; 1355 } 1356 1357 RValue CodeGenFunction::EmitBuiltinNewDeleteCall(const FunctionProtoType *Type, 1358 const CallExpr *TheCall, 1359 bool IsDelete) { 1360 CallArgList Args; 1361 EmitCallArgs(Args, Type, TheCall->arguments()); 1362 // Find the allocation or deallocation function that we're calling. 1363 ASTContext &Ctx = getContext(); 1364 DeclarationName Name = Ctx.DeclarationNames 1365 .getCXXOperatorName(IsDelete ? OO_Delete : OO_New); 1366 1367 for (auto *Decl : Ctx.getTranslationUnitDecl()->lookup(Name)) 1368 if (auto *FD = dyn_cast<FunctionDecl>(Decl)) 1369 if (Ctx.hasSameType(FD->getType(), QualType(Type, 0))) 1370 return EmitNewDeleteCall(*this, FD, Type, Args); 1371 llvm_unreachable("predeclared global operator new/delete is missing"); 1372 } 1373 1374 namespace { 1375 /// The parameters to pass to a usual operator delete. 1376 struct UsualDeleteParams { 1377 bool DestroyingDelete = false; 1378 bool Size = false; 1379 bool Alignment = false; 1380 }; 1381 } 1382 1383 static UsualDeleteParams getUsualDeleteParams(const FunctionDecl *FD) { 1384 UsualDeleteParams Params; 1385 1386 const FunctionProtoType *FPT = FD->getType()->castAs<FunctionProtoType>(); 1387 auto AI = FPT->param_type_begin(), AE = FPT->param_type_end(); 1388 1389 // The first argument is always a void*. 1390 ++AI; 1391 1392 // The next parameter may be a std::destroying_delete_t. 1393 if (FD->isDestroyingOperatorDelete()) { 1394 Params.DestroyingDelete = true; 1395 assert(AI != AE); 1396 ++AI; 1397 } 1398 1399 // Figure out what other parameters we should be implicitly passing. 1400 if (AI != AE && (*AI)->isIntegerType()) { 1401 Params.Size = true; 1402 ++AI; 1403 } 1404 1405 if (AI != AE && (*AI)->isAlignValT()) { 1406 Params.Alignment = true; 1407 ++AI; 1408 } 1409 1410 assert(AI == AE && "unexpected usual deallocation function parameter"); 1411 return Params; 1412 } 1413 1414 namespace { 1415 /// A cleanup to call the given 'operator delete' function upon abnormal 1416 /// exit from a new expression. Templated on a traits type that deals with 1417 /// ensuring that the arguments dominate the cleanup if necessary. 1418 template<typename Traits> 1419 class CallDeleteDuringNew final : public EHScopeStack::Cleanup { 1420 /// Type used to hold llvm::Value*s. 1421 typedef typename Traits::ValueTy ValueTy; 1422 /// Type used to hold RValues. 1423 typedef typename Traits::RValueTy RValueTy; 1424 struct PlacementArg { 1425 RValueTy ArgValue; 1426 QualType ArgType; 1427 }; 1428 1429 unsigned NumPlacementArgs : 31; 1430 LLVM_PREFERRED_TYPE(bool) 1431 unsigned PassAlignmentToPlacementDelete : 1; 1432 const FunctionDecl *OperatorDelete; 1433 ValueTy Ptr; 1434 ValueTy AllocSize; 1435 CharUnits AllocAlign; 1436 1437 PlacementArg *getPlacementArgs() { 1438 return reinterpret_cast<PlacementArg *>(this + 1); 1439 } 1440 1441 public: 1442 static size_t getExtraSize(size_t NumPlacementArgs) { 1443 return NumPlacementArgs * sizeof(PlacementArg); 1444 } 1445 1446 CallDeleteDuringNew(size_t NumPlacementArgs, 1447 const FunctionDecl *OperatorDelete, ValueTy Ptr, 1448 ValueTy AllocSize, bool PassAlignmentToPlacementDelete, 1449 CharUnits AllocAlign) 1450 : NumPlacementArgs(NumPlacementArgs), 1451 PassAlignmentToPlacementDelete(PassAlignmentToPlacementDelete), 1452 OperatorDelete(OperatorDelete), Ptr(Ptr), AllocSize(AllocSize), 1453 AllocAlign(AllocAlign) {} 1454 1455 void setPlacementArg(unsigned I, RValueTy Arg, QualType Type) { 1456 assert(I < NumPlacementArgs && "index out of range"); 1457 getPlacementArgs()[I] = {Arg, Type}; 1458 } 1459 1460 void Emit(CodeGenFunction &CGF, Flags flags) override { 1461 const auto *FPT = OperatorDelete->getType()->castAs<FunctionProtoType>(); 1462 CallArgList DeleteArgs; 1463 1464 // The first argument is always a void* (or C* for a destroying operator 1465 // delete for class type C). 1466 DeleteArgs.add(Traits::get(CGF, Ptr), FPT->getParamType(0)); 1467 1468 // Figure out what other parameters we should be implicitly passing. 1469 UsualDeleteParams Params; 1470 if (NumPlacementArgs) { 1471 // A placement deallocation function is implicitly passed an alignment 1472 // if the placement allocation function was, but is never passed a size. 1473 Params.Alignment = PassAlignmentToPlacementDelete; 1474 } else { 1475 // For a non-placement new-expression, 'operator delete' can take a 1476 // size and/or an alignment if it has the right parameters. 1477 Params = getUsualDeleteParams(OperatorDelete); 1478 } 1479 1480 assert(!Params.DestroyingDelete && 1481 "should not call destroying delete in a new-expression"); 1482 1483 // The second argument can be a std::size_t (for non-placement delete). 1484 if (Params.Size) 1485 DeleteArgs.add(Traits::get(CGF, AllocSize), 1486 CGF.getContext().getSizeType()); 1487 1488 // The next (second or third) argument can be a std::align_val_t, which 1489 // is an enum whose underlying type is std::size_t. 1490 // FIXME: Use the right type as the parameter type. Note that in a call 1491 // to operator delete(size_t, ...), we may not have it available. 1492 if (Params.Alignment) 1493 DeleteArgs.add(RValue::get(llvm::ConstantInt::get( 1494 CGF.SizeTy, AllocAlign.getQuantity())), 1495 CGF.getContext().getSizeType()); 1496 1497 // Pass the rest of the arguments, which must match exactly. 1498 for (unsigned I = 0; I != NumPlacementArgs; ++I) { 1499 auto Arg = getPlacementArgs()[I]; 1500 DeleteArgs.add(Traits::get(CGF, Arg.ArgValue), Arg.ArgType); 1501 } 1502 1503 // Call 'operator delete'. 1504 EmitNewDeleteCall(CGF, OperatorDelete, FPT, DeleteArgs); 1505 } 1506 }; 1507 } 1508 1509 /// Enter a cleanup to call 'operator delete' if the initializer in a 1510 /// new-expression throws. 1511 static void EnterNewDeleteCleanup(CodeGenFunction &CGF, 1512 const CXXNewExpr *E, 1513 Address NewPtr, 1514 llvm::Value *AllocSize, 1515 CharUnits AllocAlign, 1516 const CallArgList &NewArgs) { 1517 unsigned NumNonPlacementArgs = E->passAlignment() ? 2 : 1; 1518 1519 // If we're not inside a conditional branch, then the cleanup will 1520 // dominate and we can do the easier (and more efficient) thing. 1521 if (!CGF.isInConditionalBranch()) { 1522 struct DirectCleanupTraits { 1523 typedef llvm::Value *ValueTy; 1524 typedef RValue RValueTy; 1525 static RValue get(CodeGenFunction &, ValueTy V) { return RValue::get(V); } 1526 static RValue get(CodeGenFunction &, RValueTy V) { return V; } 1527 }; 1528 1529 typedef CallDeleteDuringNew<DirectCleanupTraits> DirectCleanup; 1530 1531 DirectCleanup *Cleanup = CGF.EHStack.pushCleanupWithExtra<DirectCleanup>( 1532 EHCleanup, E->getNumPlacementArgs(), E->getOperatorDelete(), 1533 NewPtr.emitRawPointer(CGF), AllocSize, E->passAlignment(), AllocAlign); 1534 for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) { 1535 auto &Arg = NewArgs[I + NumNonPlacementArgs]; 1536 Cleanup->setPlacementArg(I, Arg.getRValue(CGF), Arg.Ty); 1537 } 1538 1539 return; 1540 } 1541 1542 // Otherwise, we need to save all this stuff. 1543 DominatingValue<RValue>::saved_type SavedNewPtr = 1544 DominatingValue<RValue>::save(CGF, RValue::get(NewPtr, CGF)); 1545 DominatingValue<RValue>::saved_type SavedAllocSize = 1546 DominatingValue<RValue>::save(CGF, RValue::get(AllocSize)); 1547 1548 struct ConditionalCleanupTraits { 1549 typedef DominatingValue<RValue>::saved_type ValueTy; 1550 typedef DominatingValue<RValue>::saved_type RValueTy; 1551 static RValue get(CodeGenFunction &CGF, ValueTy V) { 1552 return V.restore(CGF); 1553 } 1554 }; 1555 typedef CallDeleteDuringNew<ConditionalCleanupTraits> ConditionalCleanup; 1556 1557 ConditionalCleanup *Cleanup = CGF.EHStack 1558 .pushCleanupWithExtra<ConditionalCleanup>(EHCleanup, 1559 E->getNumPlacementArgs(), 1560 E->getOperatorDelete(), 1561 SavedNewPtr, 1562 SavedAllocSize, 1563 E->passAlignment(), 1564 AllocAlign); 1565 for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) { 1566 auto &Arg = NewArgs[I + NumNonPlacementArgs]; 1567 Cleanup->setPlacementArg( 1568 I, DominatingValue<RValue>::save(CGF, Arg.getRValue(CGF)), Arg.Ty); 1569 } 1570 1571 CGF.initFullExprCleanup(); 1572 } 1573 1574 llvm::Value *CodeGenFunction::EmitCXXNewExpr(const CXXNewExpr *E) { 1575 // The element type being allocated. 1576 QualType allocType = getContext().getBaseElementType(E->getAllocatedType()); 1577 1578 // 1. Build a call to the allocation function. 1579 FunctionDecl *allocator = E->getOperatorNew(); 1580 1581 // If there is a brace-initializer or C++20 parenthesized initializer, cannot 1582 // allocate fewer elements than inits. 1583 unsigned minElements = 0; 1584 if (E->isArray() && E->hasInitializer()) { 1585 const Expr *Init = E->getInitializer(); 1586 const InitListExpr *ILE = dyn_cast<InitListExpr>(Init); 1587 const CXXParenListInitExpr *CPLIE = dyn_cast<CXXParenListInitExpr>(Init); 1588 const Expr *IgnoreParen = Init->IgnoreParenImpCasts(); 1589 if ((ILE && ILE->isStringLiteralInit()) || 1590 isa<StringLiteral>(IgnoreParen) || isa<ObjCEncodeExpr>(IgnoreParen)) { 1591 minElements = 1592 cast<ConstantArrayType>(Init->getType()->getAsArrayTypeUnsafe()) 1593 ->getZExtSize(); 1594 } else if (ILE || CPLIE) { 1595 minElements = ILE ? ILE->getNumInits() : CPLIE->getInitExprs().size(); 1596 } 1597 } 1598 1599 llvm::Value *numElements = nullptr; 1600 llvm::Value *allocSizeWithoutCookie = nullptr; 1601 llvm::Value *allocSize = 1602 EmitCXXNewAllocSize(*this, E, minElements, numElements, 1603 allocSizeWithoutCookie); 1604 CharUnits allocAlign = getContext().getTypeAlignInChars(allocType); 1605 1606 // Emit the allocation call. If the allocator is a global placement 1607 // operator, just "inline" it directly. 1608 Address allocation = Address::invalid(); 1609 CallArgList allocatorArgs; 1610 if (allocator->isReservedGlobalPlacementOperator()) { 1611 assert(E->getNumPlacementArgs() == 1); 1612 const Expr *arg = *E->placement_arguments().begin(); 1613 1614 LValueBaseInfo BaseInfo; 1615 allocation = EmitPointerWithAlignment(arg, &BaseInfo); 1616 1617 // The pointer expression will, in many cases, be an opaque void*. 1618 // In these cases, discard the computed alignment and use the 1619 // formal alignment of the allocated type. 1620 if (BaseInfo.getAlignmentSource() != AlignmentSource::Decl) 1621 allocation.setAlignment(allocAlign); 1622 1623 // Set up allocatorArgs for the call to operator delete if it's not 1624 // the reserved global operator. 1625 if (E->getOperatorDelete() && 1626 !E->getOperatorDelete()->isReservedGlobalPlacementOperator()) { 1627 allocatorArgs.add(RValue::get(allocSize), getContext().getSizeType()); 1628 allocatorArgs.add(RValue::get(allocation, *this), arg->getType()); 1629 } 1630 1631 } else { 1632 const FunctionProtoType *allocatorType = 1633 allocator->getType()->castAs<FunctionProtoType>(); 1634 unsigned ParamsToSkip = 0; 1635 1636 // The allocation size is the first argument. 1637 QualType sizeType = getContext().getSizeType(); 1638 allocatorArgs.add(RValue::get(allocSize), sizeType); 1639 ++ParamsToSkip; 1640 1641 if (allocSize != allocSizeWithoutCookie) { 1642 CharUnits cookieAlign = getSizeAlign(); // FIXME: Ask the ABI. 1643 allocAlign = std::max(allocAlign, cookieAlign); 1644 } 1645 1646 // The allocation alignment may be passed as the second argument. 1647 if (E->passAlignment()) { 1648 QualType AlignValT = sizeType; 1649 if (allocatorType->getNumParams() > 1) { 1650 AlignValT = allocatorType->getParamType(1); 1651 assert(getContext().hasSameUnqualifiedType( 1652 AlignValT->castAs<EnumType>()->getDecl()->getIntegerType(), 1653 sizeType) && 1654 "wrong type for alignment parameter"); 1655 ++ParamsToSkip; 1656 } else { 1657 // Corner case, passing alignment to 'operator new(size_t, ...)'. 1658 assert(allocator->isVariadic() && "can't pass alignment to allocator"); 1659 } 1660 allocatorArgs.add( 1661 RValue::get(llvm::ConstantInt::get(SizeTy, allocAlign.getQuantity())), 1662 AlignValT); 1663 } 1664 1665 // FIXME: Why do we not pass a CalleeDecl here? 1666 EmitCallArgs(allocatorArgs, allocatorType, E->placement_arguments(), 1667 /*AC*/AbstractCallee(), /*ParamsToSkip*/ParamsToSkip); 1668 1669 RValue RV = 1670 EmitNewDeleteCall(*this, allocator, allocatorType, allocatorArgs); 1671 1672 // Set !heapallocsite metadata on the call to operator new. 1673 if (getDebugInfo()) 1674 if (auto *newCall = dyn_cast<llvm::CallBase>(RV.getScalarVal())) 1675 getDebugInfo()->addHeapAllocSiteMetadata(newCall, allocType, 1676 E->getExprLoc()); 1677 1678 // If this was a call to a global replaceable allocation function that does 1679 // not take an alignment argument, the allocator is known to produce 1680 // storage that's suitably aligned for any object that fits, up to a known 1681 // threshold. Otherwise assume it's suitably aligned for the allocated type. 1682 CharUnits allocationAlign = allocAlign; 1683 if (!E->passAlignment() && 1684 allocator->isReplaceableGlobalAllocationFunction()) { 1685 unsigned AllocatorAlign = llvm::bit_floor(std::min<uint64_t>( 1686 Target.getNewAlign(), getContext().getTypeSize(allocType))); 1687 allocationAlign = std::max( 1688 allocationAlign, getContext().toCharUnitsFromBits(AllocatorAlign)); 1689 } 1690 1691 allocation = Address(RV.getScalarVal(), Int8Ty, allocationAlign); 1692 } 1693 1694 // Emit a null check on the allocation result if the allocation 1695 // function is allowed to return null (because it has a non-throwing 1696 // exception spec or is the reserved placement new) and we have an 1697 // interesting initializer will be running sanitizers on the initialization. 1698 bool nullCheck = E->shouldNullCheckAllocation() && 1699 (!allocType.isPODType(getContext()) || E->hasInitializer() || 1700 sanitizePerformTypeCheck()); 1701 1702 llvm::BasicBlock *nullCheckBB = nullptr; 1703 llvm::BasicBlock *contBB = nullptr; 1704 1705 // The null-check means that the initializer is conditionally 1706 // evaluated. 1707 ConditionalEvaluation conditional(*this); 1708 1709 if (nullCheck) { 1710 conditional.begin(*this); 1711 1712 nullCheckBB = Builder.GetInsertBlock(); 1713 llvm::BasicBlock *notNullBB = createBasicBlock("new.notnull"); 1714 contBB = createBasicBlock("new.cont"); 1715 1716 llvm::Value *isNull = Builder.CreateIsNull(allocation, "new.isnull"); 1717 Builder.CreateCondBr(isNull, contBB, notNullBB); 1718 EmitBlock(notNullBB); 1719 } 1720 1721 // If there's an operator delete, enter a cleanup to call it if an 1722 // exception is thrown. 1723 EHScopeStack::stable_iterator operatorDeleteCleanup; 1724 llvm::Instruction *cleanupDominator = nullptr; 1725 if (E->getOperatorDelete() && 1726 !E->getOperatorDelete()->isReservedGlobalPlacementOperator()) { 1727 EnterNewDeleteCleanup(*this, E, allocation, allocSize, allocAlign, 1728 allocatorArgs); 1729 operatorDeleteCleanup = EHStack.stable_begin(); 1730 cleanupDominator = Builder.CreateUnreachable(); 1731 } 1732 1733 assert((allocSize == allocSizeWithoutCookie) == 1734 CalculateCookiePadding(*this, E).isZero()); 1735 if (allocSize != allocSizeWithoutCookie) { 1736 assert(E->isArray()); 1737 allocation = CGM.getCXXABI().InitializeArrayCookie(*this, allocation, 1738 numElements, 1739 E, allocType); 1740 } 1741 1742 llvm::Type *elementTy = ConvertTypeForMem(allocType); 1743 Address result = allocation.withElementType(elementTy); 1744 1745 // Passing pointer through launder.invariant.group to avoid propagation of 1746 // vptrs information which may be included in previous type. 1747 // To not break LTO with different optimizations levels, we do it regardless 1748 // of optimization level. 1749 if (CGM.getCodeGenOpts().StrictVTablePointers && 1750 allocator->isReservedGlobalPlacementOperator()) 1751 result = Builder.CreateLaunderInvariantGroup(result); 1752 1753 // Emit sanitizer checks for pointer value now, so that in the case of an 1754 // array it was checked only once and not at each constructor call. We may 1755 // have already checked that the pointer is non-null. 1756 // FIXME: If we have an array cookie and a potentially-throwing allocator, 1757 // we'll null check the wrong pointer here. 1758 SanitizerSet SkippedChecks; 1759 SkippedChecks.set(SanitizerKind::Null, nullCheck); 1760 EmitTypeCheck(CodeGenFunction::TCK_ConstructorCall, 1761 E->getAllocatedTypeSourceInfo()->getTypeLoc().getBeginLoc(), 1762 result, allocType, result.getAlignment(), SkippedChecks, 1763 numElements); 1764 1765 EmitNewInitializer(*this, E, allocType, elementTy, result, numElements, 1766 allocSizeWithoutCookie); 1767 llvm::Value *resultPtr = result.emitRawPointer(*this); 1768 if (E->isArray()) { 1769 // NewPtr is a pointer to the base element type. If we're 1770 // allocating an array of arrays, we'll need to cast back to the 1771 // array pointer type. 1772 llvm::Type *resultType = ConvertTypeForMem(E->getType()); 1773 if (resultPtr->getType() != resultType) 1774 resultPtr = Builder.CreateBitCast(resultPtr, resultType); 1775 } 1776 1777 // Deactivate the 'operator delete' cleanup if we finished 1778 // initialization. 1779 if (operatorDeleteCleanup.isValid()) { 1780 DeactivateCleanupBlock(operatorDeleteCleanup, cleanupDominator); 1781 cleanupDominator->eraseFromParent(); 1782 } 1783 1784 if (nullCheck) { 1785 conditional.end(*this); 1786 1787 llvm::BasicBlock *notNullBB = Builder.GetInsertBlock(); 1788 EmitBlock(contBB); 1789 1790 llvm::PHINode *PHI = Builder.CreatePHI(resultPtr->getType(), 2); 1791 PHI->addIncoming(resultPtr, notNullBB); 1792 PHI->addIncoming(llvm::Constant::getNullValue(resultPtr->getType()), 1793 nullCheckBB); 1794 1795 resultPtr = PHI; 1796 } 1797 1798 return resultPtr; 1799 } 1800 1801 void CodeGenFunction::EmitDeleteCall(const FunctionDecl *DeleteFD, 1802 llvm::Value *Ptr, QualType DeleteTy, 1803 llvm::Value *NumElements, 1804 CharUnits CookieSize) { 1805 assert((!NumElements && CookieSize.isZero()) || 1806 DeleteFD->getOverloadedOperator() == OO_Array_Delete); 1807 1808 const auto *DeleteFTy = DeleteFD->getType()->castAs<FunctionProtoType>(); 1809 CallArgList DeleteArgs; 1810 1811 auto Params = getUsualDeleteParams(DeleteFD); 1812 auto ParamTypeIt = DeleteFTy->param_type_begin(); 1813 1814 // Pass the pointer itself. 1815 QualType ArgTy = *ParamTypeIt++; 1816 llvm::Value *DeletePtr = Builder.CreateBitCast(Ptr, ConvertType(ArgTy)); 1817 DeleteArgs.add(RValue::get(DeletePtr), ArgTy); 1818 1819 // Pass the std::destroying_delete tag if present. 1820 llvm::AllocaInst *DestroyingDeleteTag = nullptr; 1821 if (Params.DestroyingDelete) { 1822 QualType DDTag = *ParamTypeIt++; 1823 llvm::Type *Ty = getTypes().ConvertType(DDTag); 1824 CharUnits Align = CGM.getNaturalTypeAlignment(DDTag); 1825 DestroyingDeleteTag = CreateTempAlloca(Ty, "destroying.delete.tag"); 1826 DestroyingDeleteTag->setAlignment(Align.getAsAlign()); 1827 DeleteArgs.add( 1828 RValue::getAggregate(Address(DestroyingDeleteTag, Ty, Align)), DDTag); 1829 } 1830 1831 // Pass the size if the delete function has a size_t parameter. 1832 if (Params.Size) { 1833 QualType SizeType = *ParamTypeIt++; 1834 CharUnits DeleteTypeSize = getContext().getTypeSizeInChars(DeleteTy); 1835 llvm::Value *Size = llvm::ConstantInt::get(ConvertType(SizeType), 1836 DeleteTypeSize.getQuantity()); 1837 1838 // For array new, multiply by the number of elements. 1839 if (NumElements) 1840 Size = Builder.CreateMul(Size, NumElements); 1841 1842 // If there is a cookie, add the cookie size. 1843 if (!CookieSize.isZero()) 1844 Size = Builder.CreateAdd( 1845 Size, llvm::ConstantInt::get(SizeTy, CookieSize.getQuantity())); 1846 1847 DeleteArgs.add(RValue::get(Size), SizeType); 1848 } 1849 1850 // Pass the alignment if the delete function has an align_val_t parameter. 1851 if (Params.Alignment) { 1852 QualType AlignValType = *ParamTypeIt++; 1853 CharUnits DeleteTypeAlign = 1854 getContext().toCharUnitsFromBits(getContext().getTypeAlignIfKnown( 1855 DeleteTy, true /* NeedsPreferredAlignment */)); 1856 llvm::Value *Align = llvm::ConstantInt::get(ConvertType(AlignValType), 1857 DeleteTypeAlign.getQuantity()); 1858 DeleteArgs.add(RValue::get(Align), AlignValType); 1859 } 1860 1861 assert(ParamTypeIt == DeleteFTy->param_type_end() && 1862 "unknown parameter to usual delete function"); 1863 1864 // Emit the call to delete. 1865 EmitNewDeleteCall(*this, DeleteFD, DeleteFTy, DeleteArgs); 1866 1867 // If call argument lowering didn't use the destroying_delete_t alloca, 1868 // remove it again. 1869 if (DestroyingDeleteTag && DestroyingDeleteTag->use_empty()) 1870 DestroyingDeleteTag->eraseFromParent(); 1871 } 1872 1873 namespace { 1874 /// Calls the given 'operator delete' on a single object. 1875 struct CallObjectDelete final : EHScopeStack::Cleanup { 1876 llvm::Value *Ptr; 1877 const FunctionDecl *OperatorDelete; 1878 QualType ElementType; 1879 1880 CallObjectDelete(llvm::Value *Ptr, 1881 const FunctionDecl *OperatorDelete, 1882 QualType ElementType) 1883 : Ptr(Ptr), OperatorDelete(OperatorDelete), ElementType(ElementType) {} 1884 1885 void Emit(CodeGenFunction &CGF, Flags flags) override { 1886 CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType); 1887 } 1888 }; 1889 } 1890 1891 void 1892 CodeGenFunction::pushCallObjectDeleteCleanup(const FunctionDecl *OperatorDelete, 1893 llvm::Value *CompletePtr, 1894 QualType ElementType) { 1895 EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup, CompletePtr, 1896 OperatorDelete, ElementType); 1897 } 1898 1899 /// Emit the code for deleting a single object with a destroying operator 1900 /// delete. If the element type has a non-virtual destructor, Ptr has already 1901 /// been converted to the type of the parameter of 'operator delete'. Otherwise 1902 /// Ptr points to an object of the static type. 1903 static void EmitDestroyingObjectDelete(CodeGenFunction &CGF, 1904 const CXXDeleteExpr *DE, Address Ptr, 1905 QualType ElementType) { 1906 auto *Dtor = ElementType->getAsCXXRecordDecl()->getDestructor(); 1907 if (Dtor && Dtor->isVirtual()) 1908 CGF.CGM.getCXXABI().emitVirtualObjectDelete(CGF, DE, Ptr, ElementType, 1909 Dtor); 1910 else 1911 CGF.EmitDeleteCall(DE->getOperatorDelete(), Ptr.emitRawPointer(CGF), 1912 ElementType); 1913 } 1914 1915 /// Emit the code for deleting a single object. 1916 /// \return \c true if we started emitting UnconditionalDeleteBlock, \c false 1917 /// if not. 1918 static bool EmitObjectDelete(CodeGenFunction &CGF, 1919 const CXXDeleteExpr *DE, 1920 Address Ptr, 1921 QualType ElementType, 1922 llvm::BasicBlock *UnconditionalDeleteBlock) { 1923 // C++11 [expr.delete]p3: 1924 // If the static type of the object to be deleted is different from its 1925 // dynamic type, the static type shall be a base class of the dynamic type 1926 // of the object to be deleted and the static type shall have a virtual 1927 // destructor or the behavior is undefined. 1928 CGF.EmitTypeCheck(CodeGenFunction::TCK_MemberCall, DE->getExprLoc(), Ptr, 1929 ElementType); 1930 1931 const FunctionDecl *OperatorDelete = DE->getOperatorDelete(); 1932 assert(!OperatorDelete->isDestroyingOperatorDelete()); 1933 1934 // Find the destructor for the type, if applicable. If the 1935 // destructor is virtual, we'll just emit the vcall and return. 1936 const CXXDestructorDecl *Dtor = nullptr; 1937 if (const RecordType *RT = ElementType->getAs<RecordType>()) { 1938 CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl()); 1939 if (RD->hasDefinition() && !RD->hasTrivialDestructor()) { 1940 Dtor = RD->getDestructor(); 1941 1942 if (Dtor->isVirtual()) { 1943 bool UseVirtualCall = true; 1944 const Expr *Base = DE->getArgument(); 1945 if (auto *DevirtualizedDtor = 1946 dyn_cast_or_null<const CXXDestructorDecl>( 1947 Dtor->getDevirtualizedMethod( 1948 Base, CGF.CGM.getLangOpts().AppleKext))) { 1949 UseVirtualCall = false; 1950 const CXXRecordDecl *DevirtualizedClass = 1951 DevirtualizedDtor->getParent(); 1952 if (declaresSameEntity(getCXXRecord(Base), DevirtualizedClass)) { 1953 // Devirtualized to the class of the base type (the type of the 1954 // whole expression). 1955 Dtor = DevirtualizedDtor; 1956 } else { 1957 // Devirtualized to some other type. Would need to cast the this 1958 // pointer to that type but we don't have support for that yet, so 1959 // do a virtual call. FIXME: handle the case where it is 1960 // devirtualized to the derived type (the type of the inner 1961 // expression) as in EmitCXXMemberOrOperatorMemberCallExpr. 1962 UseVirtualCall = true; 1963 } 1964 } 1965 if (UseVirtualCall) { 1966 CGF.CGM.getCXXABI().emitVirtualObjectDelete(CGF, DE, Ptr, ElementType, 1967 Dtor); 1968 return false; 1969 } 1970 } 1971 } 1972 } 1973 1974 // Make sure that we call delete even if the dtor throws. 1975 // This doesn't have to a conditional cleanup because we're going 1976 // to pop it off in a second. 1977 CGF.EHStack.pushCleanup<CallObjectDelete>( 1978 NormalAndEHCleanup, Ptr.emitRawPointer(CGF), OperatorDelete, ElementType); 1979 1980 if (Dtor) 1981 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete, 1982 /*ForVirtualBase=*/false, 1983 /*Delegating=*/false, 1984 Ptr, ElementType); 1985 else if (auto Lifetime = ElementType.getObjCLifetime()) { 1986 switch (Lifetime) { 1987 case Qualifiers::OCL_None: 1988 case Qualifiers::OCL_ExplicitNone: 1989 case Qualifiers::OCL_Autoreleasing: 1990 break; 1991 1992 case Qualifiers::OCL_Strong: 1993 CGF.EmitARCDestroyStrong(Ptr, ARCPreciseLifetime); 1994 break; 1995 1996 case Qualifiers::OCL_Weak: 1997 CGF.EmitARCDestroyWeak(Ptr); 1998 break; 1999 } 2000 } 2001 2002 // When optimizing for size, call 'operator delete' unconditionally. 2003 if (CGF.CGM.getCodeGenOpts().OptimizeSize > 1) { 2004 CGF.EmitBlock(UnconditionalDeleteBlock); 2005 CGF.PopCleanupBlock(); 2006 return true; 2007 } 2008 2009 CGF.PopCleanupBlock(); 2010 return false; 2011 } 2012 2013 namespace { 2014 /// Calls the given 'operator delete' on an array of objects. 2015 struct CallArrayDelete final : EHScopeStack::Cleanup { 2016 llvm::Value *Ptr; 2017 const FunctionDecl *OperatorDelete; 2018 llvm::Value *NumElements; 2019 QualType ElementType; 2020 CharUnits CookieSize; 2021 2022 CallArrayDelete(llvm::Value *Ptr, 2023 const FunctionDecl *OperatorDelete, 2024 llvm::Value *NumElements, 2025 QualType ElementType, 2026 CharUnits CookieSize) 2027 : Ptr(Ptr), OperatorDelete(OperatorDelete), NumElements(NumElements), 2028 ElementType(ElementType), CookieSize(CookieSize) {} 2029 2030 void Emit(CodeGenFunction &CGF, Flags flags) override { 2031 CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType, NumElements, 2032 CookieSize); 2033 } 2034 }; 2035 } 2036 2037 /// Emit the code for deleting an array of objects. 2038 static void EmitArrayDelete(CodeGenFunction &CGF, 2039 const CXXDeleteExpr *E, 2040 Address deletedPtr, 2041 QualType elementType) { 2042 llvm::Value *numElements = nullptr; 2043 llvm::Value *allocatedPtr = nullptr; 2044 CharUnits cookieSize; 2045 CGF.CGM.getCXXABI().ReadArrayCookie(CGF, deletedPtr, E, elementType, 2046 numElements, allocatedPtr, cookieSize); 2047 2048 assert(allocatedPtr && "ReadArrayCookie didn't set allocated pointer"); 2049 2050 // Make sure that we call delete even if one of the dtors throws. 2051 const FunctionDecl *operatorDelete = E->getOperatorDelete(); 2052 CGF.EHStack.pushCleanup<CallArrayDelete>(NormalAndEHCleanup, 2053 allocatedPtr, operatorDelete, 2054 numElements, elementType, 2055 cookieSize); 2056 2057 // Destroy the elements. 2058 if (QualType::DestructionKind dtorKind = elementType.isDestructedType()) { 2059 assert(numElements && "no element count for a type with a destructor!"); 2060 2061 CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType); 2062 CharUnits elementAlign = 2063 deletedPtr.getAlignment().alignmentOfArrayElement(elementSize); 2064 2065 llvm::Value *arrayBegin = deletedPtr.emitRawPointer(CGF); 2066 llvm::Value *arrayEnd = CGF.Builder.CreateInBoundsGEP( 2067 deletedPtr.getElementType(), arrayBegin, numElements, "delete.end"); 2068 2069 // Note that it is legal to allocate a zero-length array, and we 2070 // can never fold the check away because the length should always 2071 // come from a cookie. 2072 CGF.emitArrayDestroy(arrayBegin, arrayEnd, elementType, elementAlign, 2073 CGF.getDestroyer(dtorKind), 2074 /*checkZeroLength*/ true, 2075 CGF.needsEHCleanup(dtorKind)); 2076 } 2077 2078 // Pop the cleanup block. 2079 CGF.PopCleanupBlock(); 2080 } 2081 2082 void CodeGenFunction::EmitCXXDeleteExpr(const CXXDeleteExpr *E) { 2083 const Expr *Arg = E->getArgument(); 2084 Address Ptr = EmitPointerWithAlignment(Arg); 2085 2086 // Null check the pointer. 2087 // 2088 // We could avoid this null check if we can determine that the object 2089 // destruction is trivial and doesn't require an array cookie; we can 2090 // unconditionally perform the operator delete call in that case. For now, we 2091 // assume that deleted pointers are null rarely enough that it's better to 2092 // keep the branch. This might be worth revisiting for a -O0 code size win. 2093 llvm::BasicBlock *DeleteNotNull = createBasicBlock("delete.notnull"); 2094 llvm::BasicBlock *DeleteEnd = createBasicBlock("delete.end"); 2095 2096 llvm::Value *IsNull = Builder.CreateIsNull(Ptr, "isnull"); 2097 2098 Builder.CreateCondBr(IsNull, DeleteEnd, DeleteNotNull); 2099 EmitBlock(DeleteNotNull); 2100 Ptr.setKnownNonNull(); 2101 2102 QualType DeleteTy = E->getDestroyedType(); 2103 2104 // A destroying operator delete overrides the entire operation of the 2105 // delete expression. 2106 if (E->getOperatorDelete()->isDestroyingOperatorDelete()) { 2107 EmitDestroyingObjectDelete(*this, E, Ptr, DeleteTy); 2108 EmitBlock(DeleteEnd); 2109 return; 2110 } 2111 2112 // We might be deleting a pointer to array. If so, GEP down to the 2113 // first non-array element. 2114 // (this assumes that A(*)[3][7] is converted to [3 x [7 x %A]]*) 2115 if (DeleteTy->isConstantArrayType()) { 2116 llvm::Value *Zero = Builder.getInt32(0); 2117 SmallVector<llvm::Value*,8> GEP; 2118 2119 GEP.push_back(Zero); // point at the outermost array 2120 2121 // For each layer of array type we're pointing at: 2122 while (const ConstantArrayType *Arr 2123 = getContext().getAsConstantArrayType(DeleteTy)) { 2124 // 1. Unpeel the array type. 2125 DeleteTy = Arr->getElementType(); 2126 2127 // 2. GEP to the first element of the array. 2128 GEP.push_back(Zero); 2129 } 2130 2131 Ptr = Builder.CreateInBoundsGEP(Ptr, GEP, ConvertTypeForMem(DeleteTy), 2132 Ptr.getAlignment(), "del.first"); 2133 } 2134 2135 assert(ConvertTypeForMem(DeleteTy) == Ptr.getElementType()); 2136 2137 if (E->isArrayForm()) { 2138 EmitArrayDelete(*this, E, Ptr, DeleteTy); 2139 EmitBlock(DeleteEnd); 2140 } else { 2141 if (!EmitObjectDelete(*this, E, Ptr, DeleteTy, DeleteEnd)) 2142 EmitBlock(DeleteEnd); 2143 } 2144 } 2145 2146 static llvm::Value *EmitTypeidFromVTable(CodeGenFunction &CGF, const Expr *E, 2147 llvm::Type *StdTypeInfoPtrTy, 2148 bool HasNullCheck) { 2149 // Get the vtable pointer. 2150 Address ThisPtr = CGF.EmitLValue(E).getAddress(); 2151 2152 QualType SrcRecordTy = E->getType(); 2153 2154 // C++ [class.cdtor]p4: 2155 // If the operand of typeid refers to the object under construction or 2156 // destruction and the static type of the operand is neither the constructor 2157 // or destructor’s class nor one of its bases, the behavior is undefined. 2158 CGF.EmitTypeCheck(CodeGenFunction::TCK_DynamicOperation, E->getExprLoc(), 2159 ThisPtr, SrcRecordTy); 2160 2161 // Whether we need an explicit null pointer check. For example, with the 2162 // Microsoft ABI, if this is a call to __RTtypeid, the null pointer check and 2163 // exception throw is inside the __RTtypeid(nullptr) call 2164 if (HasNullCheck && 2165 CGF.CGM.getCXXABI().shouldTypeidBeNullChecked(SrcRecordTy)) { 2166 llvm::BasicBlock *BadTypeidBlock = 2167 CGF.createBasicBlock("typeid.bad_typeid"); 2168 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("typeid.end"); 2169 2170 llvm::Value *IsNull = CGF.Builder.CreateIsNull(ThisPtr); 2171 CGF.Builder.CreateCondBr(IsNull, BadTypeidBlock, EndBlock); 2172 2173 CGF.EmitBlock(BadTypeidBlock); 2174 CGF.CGM.getCXXABI().EmitBadTypeidCall(CGF); 2175 CGF.EmitBlock(EndBlock); 2176 } 2177 2178 return CGF.CGM.getCXXABI().EmitTypeid(CGF, SrcRecordTy, ThisPtr, 2179 StdTypeInfoPtrTy); 2180 } 2181 2182 llvm::Value *CodeGenFunction::EmitCXXTypeidExpr(const CXXTypeidExpr *E) { 2183 // Ideally, we would like to use GlobalsInt8PtrTy here, however, we cannot, 2184 // primarily because the result of applying typeid is a value of type 2185 // type_info, which is declared & defined by the standard library 2186 // implementation and expects to operate on the generic (default) AS. 2187 // https://reviews.llvm.org/D157452 has more context, and a possible solution. 2188 llvm::Type *PtrTy = Int8PtrTy; 2189 LangAS GlobAS = CGM.GetGlobalVarAddressSpace(nullptr); 2190 2191 auto MaybeASCast = [=](auto &&TypeInfo) { 2192 if (GlobAS == LangAS::Default) 2193 return TypeInfo; 2194 return getTargetHooks().performAddrSpaceCast(CGM,TypeInfo, GlobAS, 2195 LangAS::Default, PtrTy); 2196 }; 2197 2198 if (E->isTypeOperand()) { 2199 llvm::Constant *TypeInfo = 2200 CGM.GetAddrOfRTTIDescriptor(E->getTypeOperand(getContext())); 2201 return MaybeASCast(TypeInfo); 2202 } 2203 2204 // C++ [expr.typeid]p2: 2205 // When typeid is applied to a glvalue expression whose type is a 2206 // polymorphic class type, the result refers to a std::type_info object 2207 // representing the type of the most derived object (that is, the dynamic 2208 // type) to which the glvalue refers. 2209 // If the operand is already most derived object, no need to look up vtable. 2210 if (E->isPotentiallyEvaluated() && !E->isMostDerived(getContext())) 2211 return EmitTypeidFromVTable(*this, E->getExprOperand(), PtrTy, 2212 E->hasNullCheck()); 2213 2214 QualType OperandTy = E->getExprOperand()->getType(); 2215 return MaybeASCast(CGM.GetAddrOfRTTIDescriptor(OperandTy)); 2216 } 2217 2218 static llvm::Value *EmitDynamicCastToNull(CodeGenFunction &CGF, 2219 QualType DestTy) { 2220 llvm::Type *DestLTy = CGF.ConvertType(DestTy); 2221 if (DestTy->isPointerType()) 2222 return llvm::Constant::getNullValue(DestLTy); 2223 2224 /// C++ [expr.dynamic.cast]p9: 2225 /// A failed cast to reference type throws std::bad_cast 2226 if (!CGF.CGM.getCXXABI().EmitBadCastCall(CGF)) 2227 return nullptr; 2228 2229 CGF.Builder.ClearInsertionPoint(); 2230 return llvm::PoisonValue::get(DestLTy); 2231 } 2232 2233 llvm::Value *CodeGenFunction::EmitDynamicCast(Address ThisAddr, 2234 const CXXDynamicCastExpr *DCE) { 2235 CGM.EmitExplicitCastExprType(DCE, this); 2236 QualType DestTy = DCE->getTypeAsWritten(); 2237 2238 QualType SrcTy = DCE->getSubExpr()->getType(); 2239 2240 // C++ [expr.dynamic.cast]p7: 2241 // If T is "pointer to cv void," then the result is a pointer to the most 2242 // derived object pointed to by v. 2243 bool IsDynamicCastToVoid = DestTy->isVoidPointerType(); 2244 QualType SrcRecordTy; 2245 QualType DestRecordTy; 2246 if (IsDynamicCastToVoid) { 2247 SrcRecordTy = SrcTy->getPointeeType(); 2248 // No DestRecordTy. 2249 } else if (const PointerType *DestPTy = DestTy->getAs<PointerType>()) { 2250 SrcRecordTy = SrcTy->castAs<PointerType>()->getPointeeType(); 2251 DestRecordTy = DestPTy->getPointeeType(); 2252 } else { 2253 SrcRecordTy = SrcTy; 2254 DestRecordTy = DestTy->castAs<ReferenceType>()->getPointeeType(); 2255 } 2256 2257 // C++ [class.cdtor]p5: 2258 // If the operand of the dynamic_cast refers to the object under 2259 // construction or destruction and the static type of the operand is not a 2260 // pointer to or object of the constructor or destructor’s own class or one 2261 // of its bases, the dynamic_cast results in undefined behavior. 2262 EmitTypeCheck(TCK_DynamicOperation, DCE->getExprLoc(), ThisAddr, SrcRecordTy); 2263 2264 if (DCE->isAlwaysNull()) { 2265 if (llvm::Value *T = EmitDynamicCastToNull(*this, DestTy)) { 2266 // Expression emission is expected to retain a valid insertion point. 2267 if (!Builder.GetInsertBlock()) 2268 EmitBlock(createBasicBlock("dynamic_cast.unreachable")); 2269 return T; 2270 } 2271 } 2272 2273 assert(SrcRecordTy->isRecordType() && "source type must be a record type!"); 2274 2275 // If the destination is effectively final, the cast succeeds if and only 2276 // if the dynamic type of the pointer is exactly the destination type. 2277 bool IsExact = !IsDynamicCastToVoid && 2278 CGM.getCodeGenOpts().OptimizationLevel > 0 && 2279 DestRecordTy->getAsCXXRecordDecl()->isEffectivelyFinal() && 2280 CGM.getCXXABI().shouldEmitExactDynamicCast(DestRecordTy); 2281 2282 // C++ [expr.dynamic.cast]p4: 2283 // If the value of v is a null pointer value in the pointer case, the result 2284 // is the null pointer value of type T. 2285 bool ShouldNullCheckSrcValue = 2286 IsExact || CGM.getCXXABI().shouldDynamicCastCallBeNullChecked( 2287 SrcTy->isPointerType(), SrcRecordTy); 2288 2289 llvm::BasicBlock *CastNull = nullptr; 2290 llvm::BasicBlock *CastNotNull = nullptr; 2291 llvm::BasicBlock *CastEnd = createBasicBlock("dynamic_cast.end"); 2292 2293 if (ShouldNullCheckSrcValue) { 2294 CastNull = createBasicBlock("dynamic_cast.null"); 2295 CastNotNull = createBasicBlock("dynamic_cast.notnull"); 2296 2297 llvm::Value *IsNull = Builder.CreateIsNull(ThisAddr); 2298 Builder.CreateCondBr(IsNull, CastNull, CastNotNull); 2299 EmitBlock(CastNotNull); 2300 } 2301 2302 llvm::Value *Value; 2303 if (IsDynamicCastToVoid) { 2304 Value = CGM.getCXXABI().emitDynamicCastToVoid(*this, ThisAddr, SrcRecordTy); 2305 } else if (IsExact) { 2306 // If the destination type is effectively final, this pointer points to the 2307 // right type if and only if its vptr has the right value. 2308 Value = CGM.getCXXABI().emitExactDynamicCast( 2309 *this, ThisAddr, SrcRecordTy, DestTy, DestRecordTy, CastEnd, CastNull); 2310 } else { 2311 assert(DestRecordTy->isRecordType() && 2312 "destination type must be a record type!"); 2313 Value = CGM.getCXXABI().emitDynamicCastCall(*this, ThisAddr, SrcRecordTy, 2314 DestTy, DestRecordTy, CastEnd); 2315 } 2316 CastNotNull = Builder.GetInsertBlock(); 2317 2318 llvm::Value *NullValue = nullptr; 2319 if (ShouldNullCheckSrcValue) { 2320 EmitBranch(CastEnd); 2321 2322 EmitBlock(CastNull); 2323 NullValue = EmitDynamicCastToNull(*this, DestTy); 2324 CastNull = Builder.GetInsertBlock(); 2325 2326 EmitBranch(CastEnd); 2327 } 2328 2329 EmitBlock(CastEnd); 2330 2331 if (CastNull) { 2332 llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2); 2333 PHI->addIncoming(Value, CastNotNull); 2334 PHI->addIncoming(NullValue, CastNull); 2335 2336 Value = PHI; 2337 } 2338 2339 return Value; 2340 } 2341