1 //===--- CodeGenFunction.cpp - Emit LLVM Code from ASTs for a Function ----===// 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 coordinates the per-function state used while generating code. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "CodeGenFunction.h" 14 #include "CGBlocks.h" 15 #include "CGCleanup.h" 16 #include "CGCUDARuntime.h" 17 #include "CGCXXABI.h" 18 #include "CGDebugInfo.h" 19 #include "CGOpenMPRuntime.h" 20 #include "CodeGenModule.h" 21 #include "CodeGenPGO.h" 22 #include "TargetInfo.h" 23 #include "clang/AST/ASTContext.h" 24 #include "clang/AST/ASTLambda.h" 25 #include "clang/AST/Decl.h" 26 #include "clang/AST/DeclCXX.h" 27 #include "clang/AST/StmtCXX.h" 28 #include "clang/AST/StmtObjC.h" 29 #include "clang/Basic/Builtins.h" 30 #include "clang/Basic/CodeGenOptions.h" 31 #include "clang/Basic/TargetInfo.h" 32 #include "clang/CodeGen/CGFunctionInfo.h" 33 #include "clang/Frontend/FrontendDiagnostic.h" 34 #include "llvm/IR/DataLayout.h" 35 #include "llvm/IR/Dominators.h" 36 #include "llvm/IR/Intrinsics.h" 37 #include "llvm/IR/MDBuilder.h" 38 #include "llvm/IR/Operator.h" 39 #include "llvm/Transforms/Utils/PromoteMemToReg.h" 40 using namespace clang; 41 using namespace CodeGen; 42 43 /// shouldEmitLifetimeMarkers - Decide whether we need emit the life-time 44 /// markers. 45 static bool shouldEmitLifetimeMarkers(const CodeGenOptions &CGOpts, 46 const LangOptions &LangOpts) { 47 if (CGOpts.DisableLifetimeMarkers) 48 return false; 49 50 // Disable lifetime markers in msan builds. 51 // FIXME: Remove this when msan works with lifetime markers. 52 if (LangOpts.Sanitize.has(SanitizerKind::Memory)) 53 return false; 54 55 // Asan uses markers for use-after-scope checks. 56 if (CGOpts.SanitizeAddressUseAfterScope) 57 return true; 58 59 // For now, only in optimized builds. 60 return CGOpts.OptimizationLevel != 0; 61 } 62 63 CodeGenFunction::CodeGenFunction(CodeGenModule &cgm, bool suppressNewContext) 64 : CodeGenTypeCache(cgm), CGM(cgm), Target(cgm.getTarget()), 65 Builder(cgm, cgm.getModule().getContext(), llvm::ConstantFolder(), 66 CGBuilderInserterTy(this)), 67 SanOpts(CGM.getLangOpts().Sanitize), DebugInfo(CGM.getModuleDebugInfo()), 68 PGO(cgm), ShouldEmitLifetimeMarkers(shouldEmitLifetimeMarkers( 69 CGM.getCodeGenOpts(), CGM.getLangOpts())) { 70 if (!suppressNewContext) 71 CGM.getCXXABI().getMangleContext().startNewFunction(); 72 73 llvm::FastMathFlags FMF; 74 if (CGM.getLangOpts().FastMath) 75 FMF.setFast(); 76 if (CGM.getLangOpts().FiniteMathOnly) { 77 FMF.setNoNaNs(); 78 FMF.setNoInfs(); 79 } 80 if (CGM.getCodeGenOpts().NoNaNsFPMath) { 81 FMF.setNoNaNs(); 82 } 83 if (CGM.getCodeGenOpts().NoSignedZeros) { 84 FMF.setNoSignedZeros(); 85 } 86 if (CGM.getCodeGenOpts().ReciprocalMath) { 87 FMF.setAllowReciprocal(); 88 } 89 if (CGM.getCodeGenOpts().Reassociate) { 90 FMF.setAllowReassoc(); 91 } 92 Builder.setFastMathFlags(FMF); 93 } 94 95 CodeGenFunction::~CodeGenFunction() { 96 assert(LifetimeExtendedCleanupStack.empty() && "failed to emit a cleanup"); 97 98 // If there are any unclaimed block infos, go ahead and destroy them 99 // now. This can happen if IR-gen gets clever and skips evaluating 100 // something. 101 if (FirstBlockInfo) 102 destroyBlockInfos(FirstBlockInfo); 103 104 if (getLangOpts().OpenMP && CurFn) 105 CGM.getOpenMPRuntime().functionFinished(*this); 106 } 107 108 CharUnits CodeGenFunction::getNaturalPointeeTypeAlignment(QualType T, 109 LValueBaseInfo *BaseInfo, 110 TBAAAccessInfo *TBAAInfo) { 111 return getNaturalTypeAlignment(T->getPointeeType(), BaseInfo, TBAAInfo, 112 /* forPointeeType= */ true); 113 } 114 115 CharUnits CodeGenFunction::getNaturalTypeAlignment(QualType T, 116 LValueBaseInfo *BaseInfo, 117 TBAAAccessInfo *TBAAInfo, 118 bool forPointeeType) { 119 if (TBAAInfo) 120 *TBAAInfo = CGM.getTBAAAccessInfo(T); 121 122 // Honor alignment typedef attributes even on incomplete types. 123 // We also honor them straight for C++ class types, even as pointees; 124 // there's an expressivity gap here. 125 if (auto TT = T->getAs<TypedefType>()) { 126 if (auto Align = TT->getDecl()->getMaxAlignment()) { 127 if (BaseInfo) 128 *BaseInfo = LValueBaseInfo(AlignmentSource::AttributedType); 129 return getContext().toCharUnitsFromBits(Align); 130 } 131 } 132 133 if (BaseInfo) 134 *BaseInfo = LValueBaseInfo(AlignmentSource::Type); 135 136 CharUnits Alignment; 137 if (T->isIncompleteType()) { 138 Alignment = CharUnits::One(); // Shouldn't be used, but pessimistic is best. 139 } else { 140 // For C++ class pointees, we don't know whether we're pointing at a 141 // base or a complete object, so we generally need to use the 142 // non-virtual alignment. 143 const CXXRecordDecl *RD; 144 if (forPointeeType && (RD = T->getAsCXXRecordDecl())) { 145 Alignment = CGM.getClassPointerAlignment(RD); 146 } else { 147 Alignment = getContext().getTypeAlignInChars(T); 148 if (T.getQualifiers().hasUnaligned()) 149 Alignment = CharUnits::One(); 150 } 151 152 // Cap to the global maximum type alignment unless the alignment 153 // was somehow explicit on the type. 154 if (unsigned MaxAlign = getLangOpts().MaxTypeAlign) { 155 if (Alignment.getQuantity() > MaxAlign && 156 !getContext().isAlignmentRequired(T)) 157 Alignment = CharUnits::fromQuantity(MaxAlign); 158 } 159 } 160 return Alignment; 161 } 162 163 LValue CodeGenFunction::MakeNaturalAlignAddrLValue(llvm::Value *V, QualType T) { 164 LValueBaseInfo BaseInfo; 165 TBAAAccessInfo TBAAInfo; 166 CharUnits Alignment = getNaturalTypeAlignment(T, &BaseInfo, &TBAAInfo); 167 return LValue::MakeAddr(Address(V, Alignment), T, getContext(), BaseInfo, 168 TBAAInfo); 169 } 170 171 /// Given a value of type T* that may not be to a complete object, 172 /// construct an l-value with the natural pointee alignment of T. 173 LValue 174 CodeGenFunction::MakeNaturalAlignPointeeAddrLValue(llvm::Value *V, QualType T) { 175 LValueBaseInfo BaseInfo; 176 TBAAAccessInfo TBAAInfo; 177 CharUnits Align = getNaturalTypeAlignment(T, &BaseInfo, &TBAAInfo, 178 /* forPointeeType= */ true); 179 return MakeAddrLValue(Address(V, Align), T, BaseInfo, TBAAInfo); 180 } 181 182 183 llvm::Type *CodeGenFunction::ConvertTypeForMem(QualType T) { 184 return CGM.getTypes().ConvertTypeForMem(T); 185 } 186 187 llvm::Type *CodeGenFunction::ConvertType(QualType T) { 188 return CGM.getTypes().ConvertType(T); 189 } 190 191 TypeEvaluationKind CodeGenFunction::getEvaluationKind(QualType type) { 192 type = type.getCanonicalType(); 193 while (true) { 194 switch (type->getTypeClass()) { 195 #define TYPE(name, parent) 196 #define ABSTRACT_TYPE(name, parent) 197 #define NON_CANONICAL_TYPE(name, parent) case Type::name: 198 #define DEPENDENT_TYPE(name, parent) case Type::name: 199 #define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(name, parent) case Type::name: 200 #include "clang/AST/TypeNodes.def" 201 llvm_unreachable("non-canonical or dependent type in IR-generation"); 202 203 case Type::Auto: 204 case Type::DeducedTemplateSpecialization: 205 llvm_unreachable("undeduced type in IR-generation"); 206 207 // Various scalar types. 208 case Type::Builtin: 209 case Type::Pointer: 210 case Type::BlockPointer: 211 case Type::LValueReference: 212 case Type::RValueReference: 213 case Type::MemberPointer: 214 case Type::Vector: 215 case Type::ExtVector: 216 case Type::FunctionProto: 217 case Type::FunctionNoProto: 218 case Type::Enum: 219 case Type::ObjCObjectPointer: 220 case Type::Pipe: 221 return TEK_Scalar; 222 223 // Complexes. 224 case Type::Complex: 225 return TEK_Complex; 226 227 // Arrays, records, and Objective-C objects. 228 case Type::ConstantArray: 229 case Type::IncompleteArray: 230 case Type::VariableArray: 231 case Type::Record: 232 case Type::ObjCObject: 233 case Type::ObjCInterface: 234 return TEK_Aggregate; 235 236 // We operate on atomic values according to their underlying type. 237 case Type::Atomic: 238 type = cast<AtomicType>(type)->getValueType(); 239 continue; 240 } 241 llvm_unreachable("unknown type kind!"); 242 } 243 } 244 245 llvm::DebugLoc CodeGenFunction::EmitReturnBlock() { 246 // For cleanliness, we try to avoid emitting the return block for 247 // simple cases. 248 llvm::BasicBlock *CurBB = Builder.GetInsertBlock(); 249 250 if (CurBB) { 251 assert(!CurBB->getTerminator() && "Unexpected terminated block."); 252 253 // We have a valid insert point, reuse it if it is empty or there are no 254 // explicit jumps to the return block. 255 if (CurBB->empty() || ReturnBlock.getBlock()->use_empty()) { 256 ReturnBlock.getBlock()->replaceAllUsesWith(CurBB); 257 delete ReturnBlock.getBlock(); 258 ReturnBlock = JumpDest(); 259 } else 260 EmitBlock(ReturnBlock.getBlock()); 261 return llvm::DebugLoc(); 262 } 263 264 // Otherwise, if the return block is the target of a single direct 265 // branch then we can just put the code in that block instead. This 266 // cleans up functions which started with a unified return block. 267 if (ReturnBlock.getBlock()->hasOneUse()) { 268 llvm::BranchInst *BI = 269 dyn_cast<llvm::BranchInst>(*ReturnBlock.getBlock()->user_begin()); 270 if (BI && BI->isUnconditional() && 271 BI->getSuccessor(0) == ReturnBlock.getBlock()) { 272 // Record/return the DebugLoc of the simple 'return' expression to be used 273 // later by the actual 'ret' instruction. 274 llvm::DebugLoc Loc = BI->getDebugLoc(); 275 Builder.SetInsertPoint(BI->getParent()); 276 BI->eraseFromParent(); 277 delete ReturnBlock.getBlock(); 278 ReturnBlock = JumpDest(); 279 return Loc; 280 } 281 } 282 283 // FIXME: We are at an unreachable point, there is no reason to emit the block 284 // unless it has uses. However, we still need a place to put the debug 285 // region.end for now. 286 287 EmitBlock(ReturnBlock.getBlock()); 288 return llvm::DebugLoc(); 289 } 290 291 static void EmitIfUsed(CodeGenFunction &CGF, llvm::BasicBlock *BB) { 292 if (!BB) return; 293 if (!BB->use_empty()) 294 return CGF.CurFn->getBasicBlockList().push_back(BB); 295 delete BB; 296 } 297 298 void CodeGenFunction::FinishFunction(SourceLocation EndLoc) { 299 assert(BreakContinueStack.empty() && 300 "mismatched push/pop in break/continue stack!"); 301 302 bool OnlySimpleReturnStmts = NumSimpleReturnExprs > 0 303 && NumSimpleReturnExprs == NumReturnExprs 304 && ReturnBlock.getBlock()->use_empty(); 305 // Usually the return expression is evaluated before the cleanup 306 // code. If the function contains only a simple return statement, 307 // such as a constant, the location before the cleanup code becomes 308 // the last useful breakpoint in the function, because the simple 309 // return expression will be evaluated after the cleanup code. To be 310 // safe, set the debug location for cleanup code to the location of 311 // the return statement. Otherwise the cleanup code should be at the 312 // end of the function's lexical scope. 313 // 314 // If there are multiple branches to the return block, the branch 315 // instructions will get the location of the return statements and 316 // all will be fine. 317 if (CGDebugInfo *DI = getDebugInfo()) { 318 if (OnlySimpleReturnStmts) 319 DI->EmitLocation(Builder, LastStopPoint); 320 else 321 DI->EmitLocation(Builder, EndLoc); 322 } 323 324 // Pop any cleanups that might have been associated with the 325 // parameters. Do this in whatever block we're currently in; it's 326 // important to do this before we enter the return block or return 327 // edges will be *really* confused. 328 bool HasCleanups = EHStack.stable_begin() != PrologueCleanupDepth; 329 bool HasOnlyLifetimeMarkers = 330 HasCleanups && EHStack.containsOnlyLifetimeMarkers(PrologueCleanupDepth); 331 bool EmitRetDbgLoc = !HasCleanups || HasOnlyLifetimeMarkers; 332 if (HasCleanups) { 333 // Make sure the line table doesn't jump back into the body for 334 // the ret after it's been at EndLoc. 335 if (CGDebugInfo *DI = getDebugInfo()) 336 if (OnlySimpleReturnStmts) 337 DI->EmitLocation(Builder, EndLoc); 338 339 PopCleanupBlocks(PrologueCleanupDepth); 340 } 341 342 // Emit function epilog (to return). 343 llvm::DebugLoc Loc = EmitReturnBlock(); 344 345 if (ShouldInstrumentFunction()) { 346 if (CGM.getCodeGenOpts().InstrumentFunctions) 347 CurFn->addFnAttr("instrument-function-exit", "__cyg_profile_func_exit"); 348 if (CGM.getCodeGenOpts().InstrumentFunctionsAfterInlining) 349 CurFn->addFnAttr("instrument-function-exit-inlined", 350 "__cyg_profile_func_exit"); 351 } 352 353 // Emit debug descriptor for function end. 354 if (CGDebugInfo *DI = getDebugInfo()) 355 DI->EmitFunctionEnd(Builder, CurFn); 356 357 // Reset the debug location to that of the simple 'return' expression, if any 358 // rather than that of the end of the function's scope '}'. 359 ApplyDebugLocation AL(*this, Loc); 360 EmitFunctionEpilog(*CurFnInfo, EmitRetDbgLoc, EndLoc); 361 EmitEndEHSpec(CurCodeDecl); 362 363 assert(EHStack.empty() && 364 "did not remove all scopes from cleanup stack!"); 365 366 // If someone did an indirect goto, emit the indirect goto block at the end of 367 // the function. 368 if (IndirectBranch) { 369 EmitBlock(IndirectBranch->getParent()); 370 Builder.ClearInsertionPoint(); 371 } 372 373 // If some of our locals escaped, insert a call to llvm.localescape in the 374 // entry block. 375 if (!EscapedLocals.empty()) { 376 // Invert the map from local to index into a simple vector. There should be 377 // no holes. 378 SmallVector<llvm::Value *, 4> EscapeArgs; 379 EscapeArgs.resize(EscapedLocals.size()); 380 for (auto &Pair : EscapedLocals) 381 EscapeArgs[Pair.second] = Pair.first; 382 llvm::Function *FrameEscapeFn = llvm::Intrinsic::getDeclaration( 383 &CGM.getModule(), llvm::Intrinsic::localescape); 384 CGBuilderTy(*this, AllocaInsertPt).CreateCall(FrameEscapeFn, EscapeArgs); 385 } 386 387 // Remove the AllocaInsertPt instruction, which is just a convenience for us. 388 llvm::Instruction *Ptr = AllocaInsertPt; 389 AllocaInsertPt = nullptr; 390 Ptr->eraseFromParent(); 391 392 // If someone took the address of a label but never did an indirect goto, we 393 // made a zero entry PHI node, which is illegal, zap it now. 394 if (IndirectBranch) { 395 llvm::PHINode *PN = cast<llvm::PHINode>(IndirectBranch->getAddress()); 396 if (PN->getNumIncomingValues() == 0) { 397 PN->replaceAllUsesWith(llvm::UndefValue::get(PN->getType())); 398 PN->eraseFromParent(); 399 } 400 } 401 402 EmitIfUsed(*this, EHResumeBlock); 403 EmitIfUsed(*this, TerminateLandingPad); 404 EmitIfUsed(*this, TerminateHandler); 405 EmitIfUsed(*this, UnreachableBlock); 406 407 for (const auto &FuncletAndParent : TerminateFunclets) 408 EmitIfUsed(*this, FuncletAndParent.second); 409 410 if (CGM.getCodeGenOpts().EmitDeclMetadata) 411 EmitDeclMetadata(); 412 413 for (SmallVectorImpl<std::pair<llvm::Instruction *, llvm::Value *> >::iterator 414 I = DeferredReplacements.begin(), 415 E = DeferredReplacements.end(); 416 I != E; ++I) { 417 I->first->replaceAllUsesWith(I->second); 418 I->first->eraseFromParent(); 419 } 420 421 // Eliminate CleanupDestSlot alloca by replacing it with SSA values and 422 // PHIs if the current function is a coroutine. We don't do it for all 423 // functions as it may result in slight increase in numbers of instructions 424 // if compiled with no optimizations. We do it for coroutine as the lifetime 425 // of CleanupDestSlot alloca make correct coroutine frame building very 426 // difficult. 427 if (NormalCleanupDest.isValid() && isCoroutine()) { 428 llvm::DominatorTree DT(*CurFn); 429 llvm::PromoteMemToReg( 430 cast<llvm::AllocaInst>(NormalCleanupDest.getPointer()), DT); 431 NormalCleanupDest = Address::invalid(); 432 } 433 434 // Scan function arguments for vector width. 435 for (llvm::Argument &A : CurFn->args()) 436 if (auto *VT = dyn_cast<llvm::VectorType>(A.getType())) 437 LargestVectorWidth = std::max(LargestVectorWidth, 438 VT->getPrimitiveSizeInBits()); 439 440 // Update vector width based on return type. 441 if (auto *VT = dyn_cast<llvm::VectorType>(CurFn->getReturnType())) 442 LargestVectorWidth = std::max(LargestVectorWidth, 443 VT->getPrimitiveSizeInBits()); 444 445 // Add the required-vector-width attribute. This contains the max width from: 446 // 1. min-vector-width attribute used in the source program. 447 // 2. Any builtins used that have a vector width specified. 448 // 3. Values passed in and out of inline assembly. 449 // 4. Width of vector arguments and return types for this function. 450 // 5. Width of vector aguments and return types for functions called by this 451 // function. 452 CurFn->addFnAttr("min-legal-vector-width", llvm::utostr(LargestVectorWidth)); 453 454 // If we generated an unreachable return block, delete it now. 455 if (ReturnBlock.isValid() && ReturnBlock.getBlock()->use_empty()) { 456 Builder.ClearInsertionPoint(); 457 ReturnBlock.getBlock()->eraseFromParent(); 458 } 459 if (ReturnValue.isValid()) { 460 auto *RetAlloca = dyn_cast<llvm::AllocaInst>(ReturnValue.getPointer()); 461 if (RetAlloca && RetAlloca->use_empty()) { 462 RetAlloca->eraseFromParent(); 463 ReturnValue = Address::invalid(); 464 } 465 } 466 } 467 468 /// ShouldInstrumentFunction - Return true if the current function should be 469 /// instrumented with __cyg_profile_func_* calls 470 bool CodeGenFunction::ShouldInstrumentFunction() { 471 if (!CGM.getCodeGenOpts().InstrumentFunctions && 472 !CGM.getCodeGenOpts().InstrumentFunctionsAfterInlining && 473 !CGM.getCodeGenOpts().InstrumentFunctionEntryBare) 474 return false; 475 if (!CurFuncDecl || CurFuncDecl->hasAttr<NoInstrumentFunctionAttr>()) 476 return false; 477 return true; 478 } 479 480 /// ShouldXRayInstrument - Return true if the current function should be 481 /// instrumented with XRay nop sleds. 482 bool CodeGenFunction::ShouldXRayInstrumentFunction() const { 483 return CGM.getCodeGenOpts().XRayInstrumentFunctions; 484 } 485 486 /// AlwaysEmitXRayCustomEvents - Return true if we should emit IR for calls to 487 /// the __xray_customevent(...) builtin calls, when doing XRay instrumentation. 488 bool CodeGenFunction::AlwaysEmitXRayCustomEvents() const { 489 return CGM.getCodeGenOpts().XRayInstrumentFunctions && 490 (CGM.getCodeGenOpts().XRayAlwaysEmitCustomEvents || 491 CGM.getCodeGenOpts().XRayInstrumentationBundle.Mask == 492 XRayInstrKind::Custom); 493 } 494 495 bool CodeGenFunction::AlwaysEmitXRayTypedEvents() const { 496 return CGM.getCodeGenOpts().XRayInstrumentFunctions && 497 (CGM.getCodeGenOpts().XRayAlwaysEmitTypedEvents || 498 CGM.getCodeGenOpts().XRayInstrumentationBundle.Mask == 499 XRayInstrKind::Typed); 500 } 501 502 llvm::Constant * 503 CodeGenFunction::EncodeAddrForUseInPrologue(llvm::Function *F, 504 llvm::Constant *Addr) { 505 // Addresses stored in prologue data can't require run-time fixups and must 506 // be PC-relative. Run-time fixups are undesirable because they necessitate 507 // writable text segments, which are unsafe. And absolute addresses are 508 // undesirable because they break PIE mode. 509 510 // Add a layer of indirection through a private global. Taking its address 511 // won't result in a run-time fixup, even if Addr has linkonce_odr linkage. 512 auto *GV = new llvm::GlobalVariable(CGM.getModule(), Addr->getType(), 513 /*isConstant=*/true, 514 llvm::GlobalValue::PrivateLinkage, Addr); 515 516 // Create a PC-relative address. 517 auto *GOTAsInt = llvm::ConstantExpr::getPtrToInt(GV, IntPtrTy); 518 auto *FuncAsInt = llvm::ConstantExpr::getPtrToInt(F, IntPtrTy); 519 auto *PCRelAsInt = llvm::ConstantExpr::getSub(GOTAsInt, FuncAsInt); 520 return (IntPtrTy == Int32Ty) 521 ? PCRelAsInt 522 : llvm::ConstantExpr::getTrunc(PCRelAsInt, Int32Ty); 523 } 524 525 llvm::Value * 526 CodeGenFunction::DecodeAddrUsedInPrologue(llvm::Value *F, 527 llvm::Value *EncodedAddr) { 528 // Reconstruct the address of the global. 529 auto *PCRelAsInt = Builder.CreateSExt(EncodedAddr, IntPtrTy); 530 auto *FuncAsInt = Builder.CreatePtrToInt(F, IntPtrTy, "func_addr.int"); 531 auto *GOTAsInt = Builder.CreateAdd(PCRelAsInt, FuncAsInt, "global_addr.int"); 532 auto *GOTAddr = Builder.CreateIntToPtr(GOTAsInt, Int8PtrPtrTy, "global_addr"); 533 534 // Load the original pointer through the global. 535 return Builder.CreateLoad(Address(GOTAddr, getPointerAlign()), 536 "decoded_addr"); 537 } 538 539 void CodeGenFunction::EmitOpenCLKernelMetadata(const FunctionDecl *FD, 540 llvm::Function *Fn) 541 { 542 if (!FD->hasAttr<OpenCLKernelAttr>()) 543 return; 544 545 llvm::LLVMContext &Context = getLLVMContext(); 546 547 CGM.GenOpenCLArgMetadata(Fn, FD, this); 548 549 if (const VecTypeHintAttr *A = FD->getAttr<VecTypeHintAttr>()) { 550 QualType HintQTy = A->getTypeHint(); 551 const ExtVectorType *HintEltQTy = HintQTy->getAs<ExtVectorType>(); 552 bool IsSignedInteger = 553 HintQTy->isSignedIntegerType() || 554 (HintEltQTy && HintEltQTy->getElementType()->isSignedIntegerType()); 555 llvm::Metadata *AttrMDArgs[] = { 556 llvm::ConstantAsMetadata::get(llvm::UndefValue::get( 557 CGM.getTypes().ConvertType(A->getTypeHint()))), 558 llvm::ConstantAsMetadata::get(llvm::ConstantInt::get( 559 llvm::IntegerType::get(Context, 32), 560 llvm::APInt(32, (uint64_t)(IsSignedInteger ? 1 : 0))))}; 561 Fn->setMetadata("vec_type_hint", llvm::MDNode::get(Context, AttrMDArgs)); 562 } 563 564 if (const WorkGroupSizeHintAttr *A = FD->getAttr<WorkGroupSizeHintAttr>()) { 565 llvm::Metadata *AttrMDArgs[] = { 566 llvm::ConstantAsMetadata::get(Builder.getInt32(A->getXDim())), 567 llvm::ConstantAsMetadata::get(Builder.getInt32(A->getYDim())), 568 llvm::ConstantAsMetadata::get(Builder.getInt32(A->getZDim()))}; 569 Fn->setMetadata("work_group_size_hint", llvm::MDNode::get(Context, AttrMDArgs)); 570 } 571 572 if (const ReqdWorkGroupSizeAttr *A = FD->getAttr<ReqdWorkGroupSizeAttr>()) { 573 llvm::Metadata *AttrMDArgs[] = { 574 llvm::ConstantAsMetadata::get(Builder.getInt32(A->getXDim())), 575 llvm::ConstantAsMetadata::get(Builder.getInt32(A->getYDim())), 576 llvm::ConstantAsMetadata::get(Builder.getInt32(A->getZDim()))}; 577 Fn->setMetadata("reqd_work_group_size", llvm::MDNode::get(Context, AttrMDArgs)); 578 } 579 580 if (const OpenCLIntelReqdSubGroupSizeAttr *A = 581 FD->getAttr<OpenCLIntelReqdSubGroupSizeAttr>()) { 582 llvm::Metadata *AttrMDArgs[] = { 583 llvm::ConstantAsMetadata::get(Builder.getInt32(A->getSubGroupSize()))}; 584 Fn->setMetadata("intel_reqd_sub_group_size", 585 llvm::MDNode::get(Context, AttrMDArgs)); 586 } 587 } 588 589 /// Determine whether the function F ends with a return stmt. 590 static bool endsWithReturn(const Decl* F) { 591 const Stmt *Body = nullptr; 592 if (auto *FD = dyn_cast_or_null<FunctionDecl>(F)) 593 Body = FD->getBody(); 594 else if (auto *OMD = dyn_cast_or_null<ObjCMethodDecl>(F)) 595 Body = OMD->getBody(); 596 597 if (auto *CS = dyn_cast_or_null<CompoundStmt>(Body)) { 598 auto LastStmt = CS->body_rbegin(); 599 if (LastStmt != CS->body_rend()) 600 return isa<ReturnStmt>(*LastStmt); 601 } 602 return false; 603 } 604 605 void CodeGenFunction::markAsIgnoreThreadCheckingAtRuntime(llvm::Function *Fn) { 606 if (SanOpts.has(SanitizerKind::Thread)) { 607 Fn->addFnAttr("sanitize_thread_no_checking_at_run_time"); 608 Fn->removeFnAttr(llvm::Attribute::SanitizeThread); 609 } 610 } 611 612 static bool matchesStlAllocatorFn(const Decl *D, const ASTContext &Ctx) { 613 auto *MD = dyn_cast_or_null<CXXMethodDecl>(D); 614 if (!MD || !MD->getDeclName().getAsIdentifierInfo() || 615 !MD->getDeclName().getAsIdentifierInfo()->isStr("allocate") || 616 (MD->getNumParams() != 1 && MD->getNumParams() != 2)) 617 return false; 618 619 if (MD->parameters()[0]->getType().getCanonicalType() != Ctx.getSizeType()) 620 return false; 621 622 if (MD->getNumParams() == 2) { 623 auto *PT = MD->parameters()[1]->getType()->getAs<PointerType>(); 624 if (!PT || !PT->isVoidPointerType() || 625 !PT->getPointeeType().isConstQualified()) 626 return false; 627 } 628 629 return true; 630 } 631 632 /// Return the UBSan prologue signature for \p FD if one is available. 633 static llvm::Constant *getPrologueSignature(CodeGenModule &CGM, 634 const FunctionDecl *FD) { 635 if (const auto *MD = dyn_cast<CXXMethodDecl>(FD)) 636 if (!MD->isStatic()) 637 return nullptr; 638 return CGM.getTargetCodeGenInfo().getUBSanFunctionSignature(CGM); 639 } 640 641 void CodeGenFunction::StartFunction(GlobalDecl GD, 642 QualType RetTy, 643 llvm::Function *Fn, 644 const CGFunctionInfo &FnInfo, 645 const FunctionArgList &Args, 646 SourceLocation Loc, 647 SourceLocation StartLoc) { 648 assert(!CurFn && 649 "Do not use a CodeGenFunction object for more than one function"); 650 651 const Decl *D = GD.getDecl(); 652 653 DidCallStackSave = false; 654 CurCodeDecl = D; 655 if (const auto *FD = dyn_cast_or_null<FunctionDecl>(D)) 656 if (FD->usesSEHTry()) 657 CurSEHParent = FD; 658 CurFuncDecl = (D ? D->getNonClosureContext() : nullptr); 659 FnRetTy = RetTy; 660 CurFn = Fn; 661 CurFnInfo = &FnInfo; 662 assert(CurFn->isDeclaration() && "Function already has body?"); 663 664 // If this function has been blacklisted for any of the enabled sanitizers, 665 // disable the sanitizer for the function. 666 do { 667 #define SANITIZER(NAME, ID) \ 668 if (SanOpts.empty()) \ 669 break; \ 670 if (SanOpts.has(SanitizerKind::ID)) \ 671 if (CGM.isInSanitizerBlacklist(SanitizerKind::ID, Fn, Loc)) \ 672 SanOpts.set(SanitizerKind::ID, false); 673 674 #include "clang/Basic/Sanitizers.def" 675 #undef SANITIZER 676 } while (0); 677 678 if (D) { 679 // Apply the no_sanitize* attributes to SanOpts. 680 for (auto Attr : D->specific_attrs<NoSanitizeAttr>()) { 681 SanitizerMask mask = Attr->getMask(); 682 SanOpts.Mask &= ~mask; 683 if (mask & SanitizerKind::Address) 684 SanOpts.set(SanitizerKind::KernelAddress, false); 685 if (mask & SanitizerKind::KernelAddress) 686 SanOpts.set(SanitizerKind::Address, false); 687 if (mask & SanitizerKind::HWAddress) 688 SanOpts.set(SanitizerKind::KernelHWAddress, false); 689 if (mask & SanitizerKind::KernelHWAddress) 690 SanOpts.set(SanitizerKind::HWAddress, false); 691 } 692 } 693 694 // Apply sanitizer attributes to the function. 695 if (SanOpts.hasOneOf(SanitizerKind::Address | SanitizerKind::KernelAddress)) 696 Fn->addFnAttr(llvm::Attribute::SanitizeAddress); 697 if (SanOpts.hasOneOf(SanitizerKind::HWAddress | SanitizerKind::KernelHWAddress)) 698 Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress); 699 if (SanOpts.has(SanitizerKind::MemTag)) 700 Fn->addFnAttr(llvm::Attribute::SanitizeMemTag); 701 if (SanOpts.has(SanitizerKind::Thread)) 702 Fn->addFnAttr(llvm::Attribute::SanitizeThread); 703 if (SanOpts.hasOneOf(SanitizerKind::Memory | SanitizerKind::KernelMemory)) 704 Fn->addFnAttr(llvm::Attribute::SanitizeMemory); 705 if (SanOpts.has(SanitizerKind::SafeStack)) 706 Fn->addFnAttr(llvm::Attribute::SafeStack); 707 if (SanOpts.has(SanitizerKind::ShadowCallStack)) 708 Fn->addFnAttr(llvm::Attribute::ShadowCallStack); 709 710 // Apply fuzzing attribute to the function. 711 if (SanOpts.hasOneOf(SanitizerKind::Fuzzer | SanitizerKind::FuzzerNoLink)) 712 Fn->addFnAttr(llvm::Attribute::OptForFuzzing); 713 714 // Ignore TSan memory acesses from within ObjC/ObjC++ dealloc, initialize, 715 // .cxx_destruct, __destroy_helper_block_ and all of their calees at run time. 716 if (SanOpts.has(SanitizerKind::Thread)) { 717 if (const auto *OMD = dyn_cast_or_null<ObjCMethodDecl>(D)) { 718 IdentifierInfo *II = OMD->getSelector().getIdentifierInfoForSlot(0); 719 if (OMD->getMethodFamily() == OMF_dealloc || 720 OMD->getMethodFamily() == OMF_initialize || 721 (OMD->getSelector().isUnarySelector() && II->isStr(".cxx_destruct"))) { 722 markAsIgnoreThreadCheckingAtRuntime(Fn); 723 } 724 } 725 } 726 727 // Ignore unrelated casts in STL allocate() since the allocator must cast 728 // from void* to T* before object initialization completes. Don't match on the 729 // namespace because not all allocators are in std:: 730 if (D && SanOpts.has(SanitizerKind::CFIUnrelatedCast)) { 731 if (matchesStlAllocatorFn(D, getContext())) 732 SanOpts.Mask &= ~SanitizerKind::CFIUnrelatedCast; 733 } 734 735 // Apply xray attributes to the function (as a string, for now) 736 if (D) { 737 if (const auto *XRayAttr = D->getAttr<XRayInstrumentAttr>()) { 738 if (CGM.getCodeGenOpts().XRayInstrumentationBundle.has( 739 XRayInstrKind::Function)) { 740 if (XRayAttr->alwaysXRayInstrument() && ShouldXRayInstrumentFunction()) 741 Fn->addFnAttr("function-instrument", "xray-always"); 742 if (XRayAttr->neverXRayInstrument()) 743 Fn->addFnAttr("function-instrument", "xray-never"); 744 if (const auto *LogArgs = D->getAttr<XRayLogArgsAttr>()) 745 if (ShouldXRayInstrumentFunction()) 746 Fn->addFnAttr("xray-log-args", 747 llvm::utostr(LogArgs->getArgumentCount())); 748 } 749 } else { 750 if (ShouldXRayInstrumentFunction() && !CGM.imbueXRayAttrs(Fn, Loc)) 751 Fn->addFnAttr( 752 "xray-instruction-threshold", 753 llvm::itostr(CGM.getCodeGenOpts().XRayInstructionThreshold)); 754 } 755 } 756 757 // Add no-jump-tables value. 758 Fn->addFnAttr("no-jump-tables", 759 llvm::toStringRef(CGM.getCodeGenOpts().NoUseJumpTables)); 760 761 // Add profile-sample-accurate value. 762 if (CGM.getCodeGenOpts().ProfileSampleAccurate) 763 Fn->addFnAttr("profile-sample-accurate"); 764 765 if (getLangOpts().OpenCL) { 766 // Add metadata for a kernel function. 767 if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) 768 EmitOpenCLKernelMetadata(FD, Fn); 769 } 770 771 // If we are checking function types, emit a function type signature as 772 // prologue data. 773 if (getLangOpts().CPlusPlus && SanOpts.has(SanitizerKind::Function)) { 774 if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) { 775 if (llvm::Constant *PrologueSig = getPrologueSignature(CGM, FD)) { 776 // Remove any (C++17) exception specifications, to allow calling e.g. a 777 // noexcept function through a non-noexcept pointer. 778 auto ProtoTy = 779 getContext().getFunctionTypeWithExceptionSpec(FD->getType(), 780 EST_None); 781 llvm::Constant *FTRTTIConst = 782 CGM.GetAddrOfRTTIDescriptor(ProtoTy, /*ForEH=*/true); 783 llvm::Constant *FTRTTIConstEncoded = 784 EncodeAddrForUseInPrologue(Fn, FTRTTIConst); 785 llvm::Constant *PrologueStructElems[] = {PrologueSig, 786 FTRTTIConstEncoded}; 787 llvm::Constant *PrologueStructConst = 788 llvm::ConstantStruct::getAnon(PrologueStructElems, /*Packed=*/true); 789 Fn->setPrologueData(PrologueStructConst); 790 } 791 } 792 } 793 794 // If we're checking nullability, we need to know whether we can check the 795 // return value. Initialize the flag to 'true' and refine it in EmitParmDecl. 796 if (SanOpts.has(SanitizerKind::NullabilityReturn)) { 797 auto Nullability = FnRetTy->getNullability(getContext()); 798 if (Nullability && *Nullability == NullabilityKind::NonNull) { 799 if (!(SanOpts.has(SanitizerKind::ReturnsNonnullAttribute) && 800 CurCodeDecl && CurCodeDecl->getAttr<ReturnsNonNullAttr>())) 801 RetValNullabilityPrecondition = 802 llvm::ConstantInt::getTrue(getLLVMContext()); 803 } 804 } 805 806 // If we're in C++ mode and the function name is "main", it is guaranteed 807 // to be norecurse by the standard (3.6.1.3 "The function main shall not be 808 // used within a program"). 809 if (getLangOpts().CPlusPlus) 810 if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) 811 if (FD->isMain()) 812 Fn->addFnAttr(llvm::Attribute::NoRecurse); 813 814 // If a custom alignment is used, force realigning to this alignment on 815 // any main function which certainly will need it. 816 if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) 817 if ((FD->isMain() || FD->isMSVCRTEntryPoint()) && 818 CGM.getCodeGenOpts().StackAlignment) 819 Fn->addFnAttr("stackrealign"); 820 821 llvm::BasicBlock *EntryBB = createBasicBlock("entry", CurFn); 822 823 // Create a marker to make it easy to insert allocas into the entryblock 824 // later. Don't create this with the builder, because we don't want it 825 // folded. 826 llvm::Value *Undef = llvm::UndefValue::get(Int32Ty); 827 AllocaInsertPt = new llvm::BitCastInst(Undef, Int32Ty, "allocapt", EntryBB); 828 829 ReturnBlock = getJumpDestInCurrentScope("return"); 830 831 Builder.SetInsertPoint(EntryBB); 832 833 // If we're checking the return value, allocate space for a pointer to a 834 // precise source location of the checked return statement. 835 if (requiresReturnValueCheck()) { 836 ReturnLocation = CreateDefaultAlignTempAlloca(Int8PtrTy, "return.sloc.ptr"); 837 InitTempAlloca(ReturnLocation, llvm::ConstantPointerNull::get(Int8PtrTy)); 838 } 839 840 // Emit subprogram debug descriptor. 841 if (CGDebugInfo *DI = getDebugInfo()) { 842 // Reconstruct the type from the argument list so that implicit parameters, 843 // such as 'this' and 'vtt', show up in the debug info. Preserve the calling 844 // convention. 845 CallingConv CC = CallingConv::CC_C; 846 if (auto *FD = dyn_cast_or_null<FunctionDecl>(D)) 847 if (const auto *SrcFnTy = FD->getType()->getAs<FunctionType>()) 848 CC = SrcFnTy->getCallConv(); 849 SmallVector<QualType, 16> ArgTypes; 850 for (const VarDecl *VD : Args) 851 ArgTypes.push_back(VD->getType()); 852 QualType FnType = getContext().getFunctionType( 853 RetTy, ArgTypes, FunctionProtoType::ExtProtoInfo(CC)); 854 DI->EmitFunctionStart(GD, Loc, StartLoc, FnType, CurFn, CurFuncIsThunk, 855 Builder); 856 } 857 858 if (ShouldInstrumentFunction()) { 859 if (CGM.getCodeGenOpts().InstrumentFunctions) 860 CurFn->addFnAttr("instrument-function-entry", "__cyg_profile_func_enter"); 861 if (CGM.getCodeGenOpts().InstrumentFunctionsAfterInlining) 862 CurFn->addFnAttr("instrument-function-entry-inlined", 863 "__cyg_profile_func_enter"); 864 if (CGM.getCodeGenOpts().InstrumentFunctionEntryBare) 865 CurFn->addFnAttr("instrument-function-entry-inlined", 866 "__cyg_profile_func_enter_bare"); 867 } 868 869 // Since emitting the mcount call here impacts optimizations such as function 870 // inlining, we just add an attribute to insert a mcount call in backend. 871 // The attribute "counting-function" is set to mcount function name which is 872 // architecture dependent. 873 if (CGM.getCodeGenOpts().InstrumentForProfiling) { 874 // Calls to fentry/mcount should not be generated if function has 875 // the no_instrument_function attribute. 876 if (!CurFuncDecl || !CurFuncDecl->hasAttr<NoInstrumentFunctionAttr>()) { 877 if (CGM.getCodeGenOpts().CallFEntry) 878 Fn->addFnAttr("fentry-call", "true"); 879 else { 880 Fn->addFnAttr("instrument-function-entry-inlined", 881 getTarget().getMCountName()); 882 } 883 } 884 } 885 886 if (RetTy->isVoidType()) { 887 // Void type; nothing to return. 888 ReturnValue = Address::invalid(); 889 890 // Count the implicit return. 891 if (!endsWithReturn(D)) 892 ++NumReturnExprs; 893 } else if (CurFnInfo->getReturnInfo().getKind() == ABIArgInfo::Indirect) { 894 // Indirect return; emit returned value directly into sret slot. 895 // This reduces code size, and affects correctness in C++. 896 auto AI = CurFn->arg_begin(); 897 if (CurFnInfo->getReturnInfo().isSRetAfterThis()) 898 ++AI; 899 ReturnValue = Address(&*AI, CurFnInfo->getReturnInfo().getIndirectAlign()); 900 if (!CurFnInfo->getReturnInfo().getIndirectByVal()) { 901 ReturnValuePointer = 902 CreateDefaultAlignTempAlloca(Int8PtrTy, "result.ptr"); 903 Builder.CreateStore(Builder.CreatePointerBitCastOrAddrSpaceCast( 904 ReturnValue.getPointer(), Int8PtrTy), 905 ReturnValuePointer); 906 } 907 } else if (CurFnInfo->getReturnInfo().getKind() == ABIArgInfo::InAlloca && 908 !hasScalarEvaluationKind(CurFnInfo->getReturnType())) { 909 // Load the sret pointer from the argument struct and return into that. 910 unsigned Idx = CurFnInfo->getReturnInfo().getInAllocaFieldIndex(); 911 llvm::Function::arg_iterator EI = CurFn->arg_end(); 912 --EI; 913 llvm::Value *Addr = Builder.CreateStructGEP(nullptr, &*EI, Idx); 914 ReturnValuePointer = Address(Addr, getPointerAlign()); 915 Addr = Builder.CreateAlignedLoad(Addr, getPointerAlign(), "agg.result"); 916 ReturnValue = Address(Addr, getNaturalTypeAlignment(RetTy)); 917 } else { 918 ReturnValue = CreateIRTemp(RetTy, "retval"); 919 920 // Tell the epilog emitter to autorelease the result. We do this 921 // now so that various specialized functions can suppress it 922 // during their IR-generation. 923 if (getLangOpts().ObjCAutoRefCount && 924 !CurFnInfo->isReturnsRetained() && 925 RetTy->isObjCRetainableType()) 926 AutoreleaseResult = true; 927 } 928 929 EmitStartEHSpec(CurCodeDecl); 930 931 PrologueCleanupDepth = EHStack.stable_begin(); 932 933 // Emit OpenMP specific initialization of the device functions. 934 if (getLangOpts().OpenMP && CurCodeDecl) 935 CGM.getOpenMPRuntime().emitFunctionProlog(*this, CurCodeDecl); 936 937 EmitFunctionProlog(*CurFnInfo, CurFn, Args); 938 939 if (D && isa<CXXMethodDecl>(D) && cast<CXXMethodDecl>(D)->isInstance()) { 940 CGM.getCXXABI().EmitInstanceFunctionProlog(*this); 941 const CXXMethodDecl *MD = cast<CXXMethodDecl>(D); 942 if (MD->getParent()->isLambda() && 943 MD->getOverloadedOperator() == OO_Call) { 944 // We're in a lambda; figure out the captures. 945 MD->getParent()->getCaptureFields(LambdaCaptureFields, 946 LambdaThisCaptureField); 947 if (LambdaThisCaptureField) { 948 // If the lambda captures the object referred to by '*this' - either by 949 // value or by reference, make sure CXXThisValue points to the correct 950 // object. 951 952 // Get the lvalue for the field (which is a copy of the enclosing object 953 // or contains the address of the enclosing object). 954 LValue ThisFieldLValue = EmitLValueForLambdaField(LambdaThisCaptureField); 955 if (!LambdaThisCaptureField->getType()->isPointerType()) { 956 // If the enclosing object was captured by value, just use its address. 957 CXXThisValue = ThisFieldLValue.getAddress().getPointer(); 958 } else { 959 // Load the lvalue pointed to by the field, since '*this' was captured 960 // by reference. 961 CXXThisValue = 962 EmitLoadOfLValue(ThisFieldLValue, SourceLocation()).getScalarVal(); 963 } 964 } 965 for (auto *FD : MD->getParent()->fields()) { 966 if (FD->hasCapturedVLAType()) { 967 auto *ExprArg = EmitLoadOfLValue(EmitLValueForLambdaField(FD), 968 SourceLocation()).getScalarVal(); 969 auto VAT = FD->getCapturedVLAType(); 970 VLASizeMap[VAT->getSizeExpr()] = ExprArg; 971 } 972 } 973 } else { 974 // Not in a lambda; just use 'this' from the method. 975 // FIXME: Should we generate a new load for each use of 'this'? The 976 // fast register allocator would be happier... 977 CXXThisValue = CXXABIThisValue; 978 } 979 980 // Check the 'this' pointer once per function, if it's available. 981 if (CXXABIThisValue) { 982 SanitizerSet SkippedChecks; 983 SkippedChecks.set(SanitizerKind::ObjectSize, true); 984 QualType ThisTy = MD->getThisType(); 985 986 // If this is the call operator of a lambda with no capture-default, it 987 // may have a static invoker function, which may call this operator with 988 // a null 'this' pointer. 989 if (isLambdaCallOperator(MD) && 990 MD->getParent()->getLambdaCaptureDefault() == LCD_None) 991 SkippedChecks.set(SanitizerKind::Null, true); 992 993 EmitTypeCheck(isa<CXXConstructorDecl>(MD) ? TCK_ConstructorCall 994 : TCK_MemberCall, 995 Loc, CXXABIThisValue, ThisTy, 996 getContext().getTypeAlignInChars(ThisTy->getPointeeType()), 997 SkippedChecks); 998 } 999 } 1000 1001 // If any of the arguments have a variably modified type, make sure to 1002 // emit the type size. 1003 for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end(); 1004 i != e; ++i) { 1005 const VarDecl *VD = *i; 1006 1007 // Dig out the type as written from ParmVarDecls; it's unclear whether 1008 // the standard (C99 6.9.1p10) requires this, but we're following the 1009 // precedent set by gcc. 1010 QualType Ty; 1011 if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(VD)) 1012 Ty = PVD->getOriginalType(); 1013 else 1014 Ty = VD->getType(); 1015 1016 if (Ty->isVariablyModifiedType()) 1017 EmitVariablyModifiedType(Ty); 1018 } 1019 // Emit a location at the end of the prologue. 1020 if (CGDebugInfo *DI = getDebugInfo()) 1021 DI->EmitLocation(Builder, StartLoc); 1022 1023 // TODO: Do we need to handle this in two places like we do with 1024 // target-features/target-cpu? 1025 if (CurFuncDecl) 1026 if (const auto *VecWidth = CurFuncDecl->getAttr<MinVectorWidthAttr>()) 1027 LargestVectorWidth = VecWidth->getVectorWidth(); 1028 } 1029 1030 void CodeGenFunction::EmitFunctionBody(const Stmt *Body) { 1031 incrementProfileCounter(Body); 1032 if (const CompoundStmt *S = dyn_cast<CompoundStmt>(Body)) 1033 EmitCompoundStmtWithoutScope(*S); 1034 else 1035 EmitStmt(Body); 1036 } 1037 1038 /// When instrumenting to collect profile data, the counts for some blocks 1039 /// such as switch cases need to not include the fall-through counts, so 1040 /// emit a branch around the instrumentation code. When not instrumenting, 1041 /// this just calls EmitBlock(). 1042 void CodeGenFunction::EmitBlockWithFallThrough(llvm::BasicBlock *BB, 1043 const Stmt *S) { 1044 llvm::BasicBlock *SkipCountBB = nullptr; 1045 if (HaveInsertPoint() && CGM.getCodeGenOpts().hasProfileClangInstr()) { 1046 // When instrumenting for profiling, the fallthrough to certain 1047 // statements needs to skip over the instrumentation code so that we 1048 // get an accurate count. 1049 SkipCountBB = createBasicBlock("skipcount"); 1050 EmitBranch(SkipCountBB); 1051 } 1052 EmitBlock(BB); 1053 uint64_t CurrentCount = getCurrentProfileCount(); 1054 incrementProfileCounter(S); 1055 setCurrentProfileCount(getCurrentProfileCount() + CurrentCount); 1056 if (SkipCountBB) 1057 EmitBlock(SkipCountBB); 1058 } 1059 1060 /// Tries to mark the given function nounwind based on the 1061 /// non-existence of any throwing calls within it. We believe this is 1062 /// lightweight enough to do at -O0. 1063 static void TryMarkNoThrow(llvm::Function *F) { 1064 // LLVM treats 'nounwind' on a function as part of the type, so we 1065 // can't do this on functions that can be overwritten. 1066 if (F->isInterposable()) return; 1067 1068 for (llvm::BasicBlock &BB : *F) 1069 for (llvm::Instruction &I : BB) 1070 if (I.mayThrow()) 1071 return; 1072 1073 F->setDoesNotThrow(); 1074 } 1075 1076 QualType CodeGenFunction::BuildFunctionArgList(GlobalDecl GD, 1077 FunctionArgList &Args) { 1078 const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl()); 1079 QualType ResTy = FD->getReturnType(); 1080 1081 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD); 1082 if (MD && MD->isInstance()) { 1083 if (CGM.getCXXABI().HasThisReturn(GD)) 1084 ResTy = MD->getThisType(); 1085 else if (CGM.getCXXABI().hasMostDerivedReturn(GD)) 1086 ResTy = CGM.getContext().VoidPtrTy; 1087 CGM.getCXXABI().buildThisParam(*this, Args); 1088 } 1089 1090 // The base version of an inheriting constructor whose constructed base is a 1091 // virtual base is not passed any arguments (because it doesn't actually call 1092 // the inherited constructor). 1093 bool PassedParams = true; 1094 if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) 1095 if (auto Inherited = CD->getInheritedConstructor()) 1096 PassedParams = 1097 getTypes().inheritingCtorHasParams(Inherited, GD.getCtorType()); 1098 1099 if (PassedParams) { 1100 for (auto *Param : FD->parameters()) { 1101 Args.push_back(Param); 1102 if (!Param->hasAttr<PassObjectSizeAttr>()) 1103 continue; 1104 1105 auto *Implicit = ImplicitParamDecl::Create( 1106 getContext(), Param->getDeclContext(), Param->getLocation(), 1107 /*Id=*/nullptr, getContext().getSizeType(), ImplicitParamDecl::Other); 1108 SizeArguments[Param] = Implicit; 1109 Args.push_back(Implicit); 1110 } 1111 } 1112 1113 if (MD && (isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD))) 1114 CGM.getCXXABI().addImplicitStructorParams(*this, ResTy, Args); 1115 1116 return ResTy; 1117 } 1118 1119 static bool 1120 shouldUseUndefinedBehaviorReturnOptimization(const FunctionDecl *FD, 1121 const ASTContext &Context) { 1122 QualType T = FD->getReturnType(); 1123 // Avoid the optimization for functions that return a record type with a 1124 // trivial destructor or another trivially copyable type. 1125 if (const RecordType *RT = T.getCanonicalType()->getAs<RecordType>()) { 1126 if (const auto *ClassDecl = dyn_cast<CXXRecordDecl>(RT->getDecl())) 1127 return !ClassDecl->hasTrivialDestructor(); 1128 } 1129 return !T.isTriviallyCopyableType(Context); 1130 } 1131 1132 void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn, 1133 const CGFunctionInfo &FnInfo) { 1134 const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl()); 1135 CurGD = GD; 1136 1137 FunctionArgList Args; 1138 QualType ResTy = BuildFunctionArgList(GD, Args); 1139 1140 // Check if we should generate debug info for this function. 1141 if (FD->hasAttr<NoDebugAttr>()) 1142 DebugInfo = nullptr; // disable debug info indefinitely for this function 1143 1144 // The function might not have a body if we're generating thunks for a 1145 // function declaration. 1146 SourceRange BodyRange; 1147 if (Stmt *Body = FD->getBody()) 1148 BodyRange = Body->getSourceRange(); 1149 else 1150 BodyRange = FD->getLocation(); 1151 CurEHLocation = BodyRange.getEnd(); 1152 1153 // Use the location of the start of the function to determine where 1154 // the function definition is located. By default use the location 1155 // of the declaration as the location for the subprogram. A function 1156 // may lack a declaration in the source code if it is created by code 1157 // gen. (examples: _GLOBAL__I_a, __cxx_global_array_dtor, thunk). 1158 SourceLocation Loc = FD->getLocation(); 1159 1160 // If this is a function specialization then use the pattern body 1161 // as the location for the function. 1162 if (const FunctionDecl *SpecDecl = FD->getTemplateInstantiationPattern()) 1163 if (SpecDecl->hasBody(SpecDecl)) 1164 Loc = SpecDecl->getLocation(); 1165 1166 Stmt *Body = FD->getBody(); 1167 1168 // Initialize helper which will detect jumps which can cause invalid lifetime 1169 // markers. 1170 if (Body && ShouldEmitLifetimeMarkers) 1171 Bypasses.Init(Body); 1172 1173 // Emit the standard function prologue. 1174 StartFunction(GD, ResTy, Fn, FnInfo, Args, Loc, BodyRange.getBegin()); 1175 1176 // Generate the body of the function. 1177 PGO.assignRegionCounters(GD, CurFn); 1178 if (isa<CXXDestructorDecl>(FD)) 1179 EmitDestructorBody(Args); 1180 else if (isa<CXXConstructorDecl>(FD)) 1181 EmitConstructorBody(Args); 1182 else if (getLangOpts().CUDA && 1183 !getLangOpts().CUDAIsDevice && 1184 FD->hasAttr<CUDAGlobalAttr>()) 1185 CGM.getCUDARuntime().emitDeviceStub(*this, Args); 1186 else if (isa<CXXMethodDecl>(FD) && 1187 cast<CXXMethodDecl>(FD)->isLambdaStaticInvoker()) { 1188 // The lambda static invoker function is special, because it forwards or 1189 // clones the body of the function call operator (but is actually static). 1190 EmitLambdaStaticInvokeBody(cast<CXXMethodDecl>(FD)); 1191 } else if (FD->isDefaulted() && isa<CXXMethodDecl>(FD) && 1192 (cast<CXXMethodDecl>(FD)->isCopyAssignmentOperator() || 1193 cast<CXXMethodDecl>(FD)->isMoveAssignmentOperator())) { 1194 // Implicit copy-assignment gets the same special treatment as implicit 1195 // copy-constructors. 1196 emitImplicitAssignmentOperatorBody(Args); 1197 } else if (Body) { 1198 EmitFunctionBody(Body); 1199 } else 1200 llvm_unreachable("no definition for emitted function"); 1201 1202 // C++11 [stmt.return]p2: 1203 // Flowing off the end of a function [...] results in undefined behavior in 1204 // a value-returning function. 1205 // C11 6.9.1p12: 1206 // If the '}' that terminates a function is reached, and the value of the 1207 // function call is used by the caller, the behavior is undefined. 1208 if (getLangOpts().CPlusPlus && !FD->hasImplicitReturnZero() && !SawAsmBlock && 1209 !FD->getReturnType()->isVoidType() && Builder.GetInsertBlock()) { 1210 bool ShouldEmitUnreachable = 1211 CGM.getCodeGenOpts().StrictReturn || 1212 shouldUseUndefinedBehaviorReturnOptimization(FD, getContext()); 1213 if (SanOpts.has(SanitizerKind::Return)) { 1214 SanitizerScope SanScope(this); 1215 llvm::Value *IsFalse = Builder.getFalse(); 1216 EmitCheck(std::make_pair(IsFalse, SanitizerKind::Return), 1217 SanitizerHandler::MissingReturn, 1218 EmitCheckSourceLocation(FD->getLocation()), None); 1219 } else if (ShouldEmitUnreachable) { 1220 if (CGM.getCodeGenOpts().OptimizationLevel == 0) 1221 EmitTrapCall(llvm::Intrinsic::trap); 1222 } 1223 if (SanOpts.has(SanitizerKind::Return) || ShouldEmitUnreachable) { 1224 Builder.CreateUnreachable(); 1225 Builder.ClearInsertionPoint(); 1226 } 1227 } 1228 1229 // Emit the standard function epilogue. 1230 FinishFunction(BodyRange.getEnd()); 1231 1232 // If we haven't marked the function nothrow through other means, do 1233 // a quick pass now to see if we can. 1234 if (!CurFn->doesNotThrow()) 1235 TryMarkNoThrow(CurFn); 1236 } 1237 1238 /// ContainsLabel - Return true if the statement contains a label in it. If 1239 /// this statement is not executed normally, it not containing a label means 1240 /// that we can just remove the code. 1241 bool CodeGenFunction::ContainsLabel(const Stmt *S, bool IgnoreCaseStmts) { 1242 // Null statement, not a label! 1243 if (!S) return false; 1244 1245 // If this is a label, we have to emit the code, consider something like: 1246 // if (0) { ... foo: bar(); } goto foo; 1247 // 1248 // TODO: If anyone cared, we could track __label__'s, since we know that you 1249 // can't jump to one from outside their declared region. 1250 if (isa<LabelStmt>(S)) 1251 return true; 1252 1253 // If this is a case/default statement, and we haven't seen a switch, we have 1254 // to emit the code. 1255 if (isa<SwitchCase>(S) && !IgnoreCaseStmts) 1256 return true; 1257 1258 // If this is a switch statement, we want to ignore cases below it. 1259 if (isa<SwitchStmt>(S)) 1260 IgnoreCaseStmts = true; 1261 1262 // Scan subexpressions for verboten labels. 1263 for (const Stmt *SubStmt : S->children()) 1264 if (ContainsLabel(SubStmt, IgnoreCaseStmts)) 1265 return true; 1266 1267 return false; 1268 } 1269 1270 /// containsBreak - Return true if the statement contains a break out of it. 1271 /// If the statement (recursively) contains a switch or loop with a break 1272 /// inside of it, this is fine. 1273 bool CodeGenFunction::containsBreak(const Stmt *S) { 1274 // Null statement, not a label! 1275 if (!S) return false; 1276 1277 // If this is a switch or loop that defines its own break scope, then we can 1278 // include it and anything inside of it. 1279 if (isa<SwitchStmt>(S) || isa<WhileStmt>(S) || isa<DoStmt>(S) || 1280 isa<ForStmt>(S)) 1281 return false; 1282 1283 if (isa<BreakStmt>(S)) 1284 return true; 1285 1286 // Scan subexpressions for verboten breaks. 1287 for (const Stmt *SubStmt : S->children()) 1288 if (containsBreak(SubStmt)) 1289 return true; 1290 1291 return false; 1292 } 1293 1294 bool CodeGenFunction::mightAddDeclToScope(const Stmt *S) { 1295 if (!S) return false; 1296 1297 // Some statement kinds add a scope and thus never add a decl to the current 1298 // scope. Note, this list is longer than the list of statements that might 1299 // have an unscoped decl nested within them, but this way is conservatively 1300 // correct even if more statement kinds are added. 1301 if (isa<IfStmt>(S) || isa<SwitchStmt>(S) || isa<WhileStmt>(S) || 1302 isa<DoStmt>(S) || isa<ForStmt>(S) || isa<CompoundStmt>(S) || 1303 isa<CXXForRangeStmt>(S) || isa<CXXTryStmt>(S) || 1304 isa<ObjCForCollectionStmt>(S) || isa<ObjCAtTryStmt>(S)) 1305 return false; 1306 1307 if (isa<DeclStmt>(S)) 1308 return true; 1309 1310 for (const Stmt *SubStmt : S->children()) 1311 if (mightAddDeclToScope(SubStmt)) 1312 return true; 1313 1314 return false; 1315 } 1316 1317 /// ConstantFoldsToSimpleInteger - If the specified expression does not fold 1318 /// to a constant, or if it does but contains a label, return false. If it 1319 /// constant folds return true and set the boolean result in Result. 1320 bool CodeGenFunction::ConstantFoldsToSimpleInteger(const Expr *Cond, 1321 bool &ResultBool, 1322 bool AllowLabels) { 1323 llvm::APSInt ResultInt; 1324 if (!ConstantFoldsToSimpleInteger(Cond, ResultInt, AllowLabels)) 1325 return false; 1326 1327 ResultBool = ResultInt.getBoolValue(); 1328 return true; 1329 } 1330 1331 /// ConstantFoldsToSimpleInteger - If the specified expression does not fold 1332 /// to a constant, or if it does but contains a label, return false. If it 1333 /// constant folds return true and set the folded value. 1334 bool CodeGenFunction::ConstantFoldsToSimpleInteger(const Expr *Cond, 1335 llvm::APSInt &ResultInt, 1336 bool AllowLabels) { 1337 // FIXME: Rename and handle conversion of other evaluatable things 1338 // to bool. 1339 Expr::EvalResult Result; 1340 if (!Cond->EvaluateAsInt(Result, getContext())) 1341 return false; // Not foldable, not integer or not fully evaluatable. 1342 1343 llvm::APSInt Int = Result.Val.getInt(); 1344 if (!AllowLabels && CodeGenFunction::ContainsLabel(Cond)) 1345 return false; // Contains a label. 1346 1347 ResultInt = Int; 1348 return true; 1349 } 1350 1351 1352 1353 /// EmitBranchOnBoolExpr - Emit a branch on a boolean condition (e.g. for an if 1354 /// statement) to the specified blocks. Based on the condition, this might try 1355 /// to simplify the codegen of the conditional based on the branch. 1356 /// 1357 void CodeGenFunction::EmitBranchOnBoolExpr(const Expr *Cond, 1358 llvm::BasicBlock *TrueBlock, 1359 llvm::BasicBlock *FalseBlock, 1360 uint64_t TrueCount) { 1361 Cond = Cond->IgnoreParens(); 1362 1363 if (const BinaryOperator *CondBOp = dyn_cast<BinaryOperator>(Cond)) { 1364 1365 // Handle X && Y in a condition. 1366 if (CondBOp->getOpcode() == BO_LAnd) { 1367 // If we have "1 && X", simplify the code. "0 && X" would have constant 1368 // folded if the case was simple enough. 1369 bool ConstantBool = false; 1370 if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) && 1371 ConstantBool) { 1372 // br(1 && X) -> br(X). 1373 incrementProfileCounter(CondBOp); 1374 return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock, 1375 TrueCount); 1376 } 1377 1378 // If we have "X && 1", simplify the code to use an uncond branch. 1379 // "X && 0" would have been constant folded to 0. 1380 if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) && 1381 ConstantBool) { 1382 // br(X && 1) -> br(X). 1383 return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock, 1384 TrueCount); 1385 } 1386 1387 // Emit the LHS as a conditional. If the LHS conditional is false, we 1388 // want to jump to the FalseBlock. 1389 llvm::BasicBlock *LHSTrue = createBasicBlock("land.lhs.true"); 1390 // The counter tells us how often we evaluate RHS, and all of TrueCount 1391 // can be propagated to that branch. 1392 uint64_t RHSCount = getProfileCount(CondBOp->getRHS()); 1393 1394 ConditionalEvaluation eval(*this); 1395 { 1396 ApplyDebugLocation DL(*this, Cond); 1397 EmitBranchOnBoolExpr(CondBOp->getLHS(), LHSTrue, FalseBlock, RHSCount); 1398 EmitBlock(LHSTrue); 1399 } 1400 1401 incrementProfileCounter(CondBOp); 1402 setCurrentProfileCount(getProfileCount(CondBOp->getRHS())); 1403 1404 // Any temporaries created here are conditional. 1405 eval.begin(*this); 1406 EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock, TrueCount); 1407 eval.end(*this); 1408 1409 return; 1410 } 1411 1412 if (CondBOp->getOpcode() == BO_LOr) { 1413 // If we have "0 || X", simplify the code. "1 || X" would have constant 1414 // folded if the case was simple enough. 1415 bool ConstantBool = false; 1416 if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) && 1417 !ConstantBool) { 1418 // br(0 || X) -> br(X). 1419 incrementProfileCounter(CondBOp); 1420 return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock, 1421 TrueCount); 1422 } 1423 1424 // If we have "X || 0", simplify the code to use an uncond branch. 1425 // "X || 1" would have been constant folded to 1. 1426 if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) && 1427 !ConstantBool) { 1428 // br(X || 0) -> br(X). 1429 return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock, 1430 TrueCount); 1431 } 1432 1433 // Emit the LHS as a conditional. If the LHS conditional is true, we 1434 // want to jump to the TrueBlock. 1435 llvm::BasicBlock *LHSFalse = createBasicBlock("lor.lhs.false"); 1436 // We have the count for entry to the RHS and for the whole expression 1437 // being true, so we can divy up True count between the short circuit and 1438 // the RHS. 1439 uint64_t LHSCount = 1440 getCurrentProfileCount() - getProfileCount(CondBOp->getRHS()); 1441 uint64_t RHSCount = TrueCount - LHSCount; 1442 1443 ConditionalEvaluation eval(*this); 1444 { 1445 ApplyDebugLocation DL(*this, Cond); 1446 EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, LHSFalse, LHSCount); 1447 EmitBlock(LHSFalse); 1448 } 1449 1450 incrementProfileCounter(CondBOp); 1451 setCurrentProfileCount(getProfileCount(CondBOp->getRHS())); 1452 1453 // Any temporaries created here are conditional. 1454 eval.begin(*this); 1455 EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock, RHSCount); 1456 1457 eval.end(*this); 1458 1459 return; 1460 } 1461 } 1462 1463 if (const UnaryOperator *CondUOp = dyn_cast<UnaryOperator>(Cond)) { 1464 // br(!x, t, f) -> br(x, f, t) 1465 if (CondUOp->getOpcode() == UO_LNot) { 1466 // Negate the count. 1467 uint64_t FalseCount = getCurrentProfileCount() - TrueCount; 1468 // Negate the condition and swap the destination blocks. 1469 return EmitBranchOnBoolExpr(CondUOp->getSubExpr(), FalseBlock, TrueBlock, 1470 FalseCount); 1471 } 1472 } 1473 1474 if (const ConditionalOperator *CondOp = dyn_cast<ConditionalOperator>(Cond)) { 1475 // br(c ? x : y, t, f) -> br(c, br(x, t, f), br(y, t, f)) 1476 llvm::BasicBlock *LHSBlock = createBasicBlock("cond.true"); 1477 llvm::BasicBlock *RHSBlock = createBasicBlock("cond.false"); 1478 1479 ConditionalEvaluation cond(*this); 1480 EmitBranchOnBoolExpr(CondOp->getCond(), LHSBlock, RHSBlock, 1481 getProfileCount(CondOp)); 1482 1483 // When computing PGO branch weights, we only know the overall count for 1484 // the true block. This code is essentially doing tail duplication of the 1485 // naive code-gen, introducing new edges for which counts are not 1486 // available. Divide the counts proportionally between the LHS and RHS of 1487 // the conditional operator. 1488 uint64_t LHSScaledTrueCount = 0; 1489 if (TrueCount) { 1490 double LHSRatio = 1491 getProfileCount(CondOp) / (double)getCurrentProfileCount(); 1492 LHSScaledTrueCount = TrueCount * LHSRatio; 1493 } 1494 1495 cond.begin(*this); 1496 EmitBlock(LHSBlock); 1497 incrementProfileCounter(CondOp); 1498 { 1499 ApplyDebugLocation DL(*this, Cond); 1500 EmitBranchOnBoolExpr(CondOp->getLHS(), TrueBlock, FalseBlock, 1501 LHSScaledTrueCount); 1502 } 1503 cond.end(*this); 1504 1505 cond.begin(*this); 1506 EmitBlock(RHSBlock); 1507 EmitBranchOnBoolExpr(CondOp->getRHS(), TrueBlock, FalseBlock, 1508 TrueCount - LHSScaledTrueCount); 1509 cond.end(*this); 1510 1511 return; 1512 } 1513 1514 if (const CXXThrowExpr *Throw = dyn_cast<CXXThrowExpr>(Cond)) { 1515 // Conditional operator handling can give us a throw expression as a 1516 // condition for a case like: 1517 // br(c ? throw x : y, t, f) -> br(c, br(throw x, t, f), br(y, t, f) 1518 // Fold this to: 1519 // br(c, throw x, br(y, t, f)) 1520 EmitCXXThrowExpr(Throw, /*KeepInsertionPoint*/false); 1521 return; 1522 } 1523 1524 // If the branch has a condition wrapped by __builtin_unpredictable, 1525 // create metadata that specifies that the branch is unpredictable. 1526 // Don't bother if not optimizing because that metadata would not be used. 1527 llvm::MDNode *Unpredictable = nullptr; 1528 auto *Call = dyn_cast<CallExpr>(Cond->IgnoreImpCasts()); 1529 if (Call && CGM.getCodeGenOpts().OptimizationLevel != 0) { 1530 auto *FD = dyn_cast_or_null<FunctionDecl>(Call->getCalleeDecl()); 1531 if (FD && FD->getBuiltinID() == Builtin::BI__builtin_unpredictable) { 1532 llvm::MDBuilder MDHelper(getLLVMContext()); 1533 Unpredictable = MDHelper.createUnpredictable(); 1534 } 1535 } 1536 1537 // Create branch weights based on the number of times we get here and the 1538 // number of times the condition should be true. 1539 uint64_t CurrentCount = std::max(getCurrentProfileCount(), TrueCount); 1540 llvm::MDNode *Weights = 1541 createProfileWeights(TrueCount, CurrentCount - TrueCount); 1542 1543 // Emit the code with the fully general case. 1544 llvm::Value *CondV; 1545 { 1546 ApplyDebugLocation DL(*this, Cond); 1547 CondV = EvaluateExprAsBool(Cond); 1548 } 1549 Builder.CreateCondBr(CondV, TrueBlock, FalseBlock, Weights, Unpredictable); 1550 } 1551 1552 /// ErrorUnsupported - Print out an error that codegen doesn't support the 1553 /// specified stmt yet. 1554 void CodeGenFunction::ErrorUnsupported(const Stmt *S, const char *Type) { 1555 CGM.ErrorUnsupported(S, Type); 1556 } 1557 1558 /// emitNonZeroVLAInit - Emit the "zero" initialization of a 1559 /// variable-length array whose elements have a non-zero bit-pattern. 1560 /// 1561 /// \param baseType the inner-most element type of the array 1562 /// \param src - a char* pointing to the bit-pattern for a single 1563 /// base element of the array 1564 /// \param sizeInChars - the total size of the VLA, in chars 1565 static void emitNonZeroVLAInit(CodeGenFunction &CGF, QualType baseType, 1566 Address dest, Address src, 1567 llvm::Value *sizeInChars) { 1568 CGBuilderTy &Builder = CGF.Builder; 1569 1570 CharUnits baseSize = CGF.getContext().getTypeSizeInChars(baseType); 1571 llvm::Value *baseSizeInChars 1572 = llvm::ConstantInt::get(CGF.IntPtrTy, baseSize.getQuantity()); 1573 1574 Address begin = 1575 Builder.CreateElementBitCast(dest, CGF.Int8Ty, "vla.begin"); 1576 llvm::Value *end = 1577 Builder.CreateInBoundsGEP(begin.getPointer(), sizeInChars, "vla.end"); 1578 1579 llvm::BasicBlock *originBB = CGF.Builder.GetInsertBlock(); 1580 llvm::BasicBlock *loopBB = CGF.createBasicBlock("vla-init.loop"); 1581 llvm::BasicBlock *contBB = CGF.createBasicBlock("vla-init.cont"); 1582 1583 // Make a loop over the VLA. C99 guarantees that the VLA element 1584 // count must be nonzero. 1585 CGF.EmitBlock(loopBB); 1586 1587 llvm::PHINode *cur = Builder.CreatePHI(begin.getType(), 2, "vla.cur"); 1588 cur->addIncoming(begin.getPointer(), originBB); 1589 1590 CharUnits curAlign = 1591 dest.getAlignment().alignmentOfArrayElement(baseSize); 1592 1593 // memcpy the individual element bit-pattern. 1594 Builder.CreateMemCpy(Address(cur, curAlign), src, baseSizeInChars, 1595 /*volatile*/ false); 1596 1597 // Go to the next element. 1598 llvm::Value *next = 1599 Builder.CreateInBoundsGEP(CGF.Int8Ty, cur, baseSizeInChars, "vla.next"); 1600 1601 // Leave if that's the end of the VLA. 1602 llvm::Value *done = Builder.CreateICmpEQ(next, end, "vla-init.isdone"); 1603 Builder.CreateCondBr(done, contBB, loopBB); 1604 cur->addIncoming(next, loopBB); 1605 1606 CGF.EmitBlock(contBB); 1607 } 1608 1609 void 1610 CodeGenFunction::EmitNullInitialization(Address DestPtr, QualType Ty) { 1611 // Ignore empty classes in C++. 1612 if (getLangOpts().CPlusPlus) { 1613 if (const RecordType *RT = Ty->getAs<RecordType>()) { 1614 if (cast<CXXRecordDecl>(RT->getDecl())->isEmpty()) 1615 return; 1616 } 1617 } 1618 1619 // Cast the dest ptr to the appropriate i8 pointer type. 1620 if (DestPtr.getElementType() != Int8Ty) 1621 DestPtr = Builder.CreateElementBitCast(DestPtr, Int8Ty); 1622 1623 // Get size and alignment info for this aggregate. 1624 CharUnits size = getContext().getTypeSizeInChars(Ty); 1625 1626 llvm::Value *SizeVal; 1627 const VariableArrayType *vla; 1628 1629 // Don't bother emitting a zero-byte memset. 1630 if (size.isZero()) { 1631 // But note that getTypeInfo returns 0 for a VLA. 1632 if (const VariableArrayType *vlaType = 1633 dyn_cast_or_null<VariableArrayType>( 1634 getContext().getAsArrayType(Ty))) { 1635 auto VlaSize = getVLASize(vlaType); 1636 SizeVal = VlaSize.NumElts; 1637 CharUnits eltSize = getContext().getTypeSizeInChars(VlaSize.Type); 1638 if (!eltSize.isOne()) 1639 SizeVal = Builder.CreateNUWMul(SizeVal, CGM.getSize(eltSize)); 1640 vla = vlaType; 1641 } else { 1642 return; 1643 } 1644 } else { 1645 SizeVal = CGM.getSize(size); 1646 vla = nullptr; 1647 } 1648 1649 // If the type contains a pointer to data member we can't memset it to zero. 1650 // Instead, create a null constant and copy it to the destination. 1651 // TODO: there are other patterns besides zero that we can usefully memset, 1652 // like -1, which happens to be the pattern used by member-pointers. 1653 if (!CGM.getTypes().isZeroInitializable(Ty)) { 1654 // For a VLA, emit a single element, then splat that over the VLA. 1655 if (vla) Ty = getContext().getBaseElementType(vla); 1656 1657 llvm::Constant *NullConstant = CGM.EmitNullConstant(Ty); 1658 1659 llvm::GlobalVariable *NullVariable = 1660 new llvm::GlobalVariable(CGM.getModule(), NullConstant->getType(), 1661 /*isConstant=*/true, 1662 llvm::GlobalVariable::PrivateLinkage, 1663 NullConstant, Twine()); 1664 CharUnits NullAlign = DestPtr.getAlignment(); 1665 NullVariable->setAlignment(NullAlign.getQuantity()); 1666 Address SrcPtr(Builder.CreateBitCast(NullVariable, Builder.getInt8PtrTy()), 1667 NullAlign); 1668 1669 if (vla) return emitNonZeroVLAInit(*this, Ty, DestPtr, SrcPtr, SizeVal); 1670 1671 // Get and call the appropriate llvm.memcpy overload. 1672 Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, false); 1673 return; 1674 } 1675 1676 // Otherwise, just memset the whole thing to zero. This is legal 1677 // because in LLVM, all default initializers (other than the ones we just 1678 // handled above) are guaranteed to have a bit pattern of all zeros. 1679 Builder.CreateMemSet(DestPtr, Builder.getInt8(0), SizeVal, false); 1680 } 1681 1682 llvm::BlockAddress *CodeGenFunction::GetAddrOfLabel(const LabelDecl *L) { 1683 // Make sure that there is a block for the indirect goto. 1684 if (!IndirectBranch) 1685 GetIndirectGotoBlock(); 1686 1687 llvm::BasicBlock *BB = getJumpDestForLabel(L).getBlock(); 1688 1689 // Make sure the indirect branch includes all of the address-taken blocks. 1690 IndirectBranch->addDestination(BB); 1691 return llvm::BlockAddress::get(CurFn, BB); 1692 } 1693 1694 llvm::BasicBlock *CodeGenFunction::GetIndirectGotoBlock() { 1695 // If we already made the indirect branch for indirect goto, return its block. 1696 if (IndirectBranch) return IndirectBranch->getParent(); 1697 1698 CGBuilderTy TmpBuilder(*this, createBasicBlock("indirectgoto")); 1699 1700 // Create the PHI node that indirect gotos will add entries to. 1701 llvm::Value *DestVal = TmpBuilder.CreatePHI(Int8PtrTy, 0, 1702 "indirect.goto.dest"); 1703 1704 // Create the indirect branch instruction. 1705 IndirectBranch = TmpBuilder.CreateIndirectBr(DestVal); 1706 return IndirectBranch->getParent(); 1707 } 1708 1709 /// Computes the length of an array in elements, as well as the base 1710 /// element type and a properly-typed first element pointer. 1711 llvm::Value *CodeGenFunction::emitArrayLength(const ArrayType *origArrayType, 1712 QualType &baseType, 1713 Address &addr) { 1714 const ArrayType *arrayType = origArrayType; 1715 1716 // If it's a VLA, we have to load the stored size. Note that 1717 // this is the size of the VLA in bytes, not its size in elements. 1718 llvm::Value *numVLAElements = nullptr; 1719 if (isa<VariableArrayType>(arrayType)) { 1720 numVLAElements = getVLASize(cast<VariableArrayType>(arrayType)).NumElts; 1721 1722 // Walk into all VLAs. This doesn't require changes to addr, 1723 // which has type T* where T is the first non-VLA element type. 1724 do { 1725 QualType elementType = arrayType->getElementType(); 1726 arrayType = getContext().getAsArrayType(elementType); 1727 1728 // If we only have VLA components, 'addr' requires no adjustment. 1729 if (!arrayType) { 1730 baseType = elementType; 1731 return numVLAElements; 1732 } 1733 } while (isa<VariableArrayType>(arrayType)); 1734 1735 // We get out here only if we find a constant array type 1736 // inside the VLA. 1737 } 1738 1739 // We have some number of constant-length arrays, so addr should 1740 // have LLVM type [M x [N x [...]]]*. Build a GEP that walks 1741 // down to the first element of addr. 1742 SmallVector<llvm::Value*, 8> gepIndices; 1743 1744 // GEP down to the array type. 1745 llvm::ConstantInt *zero = Builder.getInt32(0); 1746 gepIndices.push_back(zero); 1747 1748 uint64_t countFromCLAs = 1; 1749 QualType eltType; 1750 1751 llvm::ArrayType *llvmArrayType = 1752 dyn_cast<llvm::ArrayType>(addr.getElementType()); 1753 while (llvmArrayType) { 1754 assert(isa<ConstantArrayType>(arrayType)); 1755 assert(cast<ConstantArrayType>(arrayType)->getSize().getZExtValue() 1756 == llvmArrayType->getNumElements()); 1757 1758 gepIndices.push_back(zero); 1759 countFromCLAs *= llvmArrayType->getNumElements(); 1760 eltType = arrayType->getElementType(); 1761 1762 llvmArrayType = 1763 dyn_cast<llvm::ArrayType>(llvmArrayType->getElementType()); 1764 arrayType = getContext().getAsArrayType(arrayType->getElementType()); 1765 assert((!llvmArrayType || arrayType) && 1766 "LLVM and Clang types are out-of-synch"); 1767 } 1768 1769 if (arrayType) { 1770 // From this point onwards, the Clang array type has been emitted 1771 // as some other type (probably a packed struct). Compute the array 1772 // size, and just emit the 'begin' expression as a bitcast. 1773 while (arrayType) { 1774 countFromCLAs *= 1775 cast<ConstantArrayType>(arrayType)->getSize().getZExtValue(); 1776 eltType = arrayType->getElementType(); 1777 arrayType = getContext().getAsArrayType(eltType); 1778 } 1779 1780 llvm::Type *baseType = ConvertType(eltType); 1781 addr = Builder.CreateElementBitCast(addr, baseType, "array.begin"); 1782 } else { 1783 // Create the actual GEP. 1784 addr = Address(Builder.CreateInBoundsGEP(addr.getPointer(), 1785 gepIndices, "array.begin"), 1786 addr.getAlignment()); 1787 } 1788 1789 baseType = eltType; 1790 1791 llvm::Value *numElements 1792 = llvm::ConstantInt::get(SizeTy, countFromCLAs); 1793 1794 // If we had any VLA dimensions, factor them in. 1795 if (numVLAElements) 1796 numElements = Builder.CreateNUWMul(numVLAElements, numElements); 1797 1798 return numElements; 1799 } 1800 1801 CodeGenFunction::VlaSizePair CodeGenFunction::getVLASize(QualType type) { 1802 const VariableArrayType *vla = getContext().getAsVariableArrayType(type); 1803 assert(vla && "type was not a variable array type!"); 1804 return getVLASize(vla); 1805 } 1806 1807 CodeGenFunction::VlaSizePair 1808 CodeGenFunction::getVLASize(const VariableArrayType *type) { 1809 // The number of elements so far; always size_t. 1810 llvm::Value *numElements = nullptr; 1811 1812 QualType elementType; 1813 do { 1814 elementType = type->getElementType(); 1815 llvm::Value *vlaSize = VLASizeMap[type->getSizeExpr()]; 1816 assert(vlaSize && "no size for VLA!"); 1817 assert(vlaSize->getType() == SizeTy); 1818 1819 if (!numElements) { 1820 numElements = vlaSize; 1821 } else { 1822 // It's undefined behavior if this wraps around, so mark it that way. 1823 // FIXME: Teach -fsanitize=undefined to trap this. 1824 numElements = Builder.CreateNUWMul(numElements, vlaSize); 1825 } 1826 } while ((type = getContext().getAsVariableArrayType(elementType))); 1827 1828 return { numElements, elementType }; 1829 } 1830 1831 CodeGenFunction::VlaSizePair 1832 CodeGenFunction::getVLAElements1D(QualType type) { 1833 const VariableArrayType *vla = getContext().getAsVariableArrayType(type); 1834 assert(vla && "type was not a variable array type!"); 1835 return getVLAElements1D(vla); 1836 } 1837 1838 CodeGenFunction::VlaSizePair 1839 CodeGenFunction::getVLAElements1D(const VariableArrayType *Vla) { 1840 llvm::Value *VlaSize = VLASizeMap[Vla->getSizeExpr()]; 1841 assert(VlaSize && "no size for VLA!"); 1842 assert(VlaSize->getType() == SizeTy); 1843 return { VlaSize, Vla->getElementType() }; 1844 } 1845 1846 void CodeGenFunction::EmitVariablyModifiedType(QualType type) { 1847 assert(type->isVariablyModifiedType() && 1848 "Must pass variably modified type to EmitVLASizes!"); 1849 1850 EnsureInsertPoint(); 1851 1852 // We're going to walk down into the type and look for VLA 1853 // expressions. 1854 do { 1855 assert(type->isVariablyModifiedType()); 1856 1857 const Type *ty = type.getTypePtr(); 1858 switch (ty->getTypeClass()) { 1859 1860 #define TYPE(Class, Base) 1861 #define ABSTRACT_TYPE(Class, Base) 1862 #define NON_CANONICAL_TYPE(Class, Base) 1863 #define DEPENDENT_TYPE(Class, Base) case Type::Class: 1864 #define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) 1865 #include "clang/AST/TypeNodes.def" 1866 llvm_unreachable("unexpected dependent type!"); 1867 1868 // These types are never variably-modified. 1869 case Type::Builtin: 1870 case Type::Complex: 1871 case Type::Vector: 1872 case Type::ExtVector: 1873 case Type::Record: 1874 case Type::Enum: 1875 case Type::Elaborated: 1876 case Type::TemplateSpecialization: 1877 case Type::ObjCTypeParam: 1878 case Type::ObjCObject: 1879 case Type::ObjCInterface: 1880 case Type::ObjCObjectPointer: 1881 llvm_unreachable("type class is never variably-modified!"); 1882 1883 case Type::Adjusted: 1884 type = cast<AdjustedType>(ty)->getAdjustedType(); 1885 break; 1886 1887 case Type::Decayed: 1888 type = cast<DecayedType>(ty)->getPointeeType(); 1889 break; 1890 1891 case Type::Pointer: 1892 type = cast<PointerType>(ty)->getPointeeType(); 1893 break; 1894 1895 case Type::BlockPointer: 1896 type = cast<BlockPointerType>(ty)->getPointeeType(); 1897 break; 1898 1899 case Type::LValueReference: 1900 case Type::RValueReference: 1901 type = cast<ReferenceType>(ty)->getPointeeType(); 1902 break; 1903 1904 case Type::MemberPointer: 1905 type = cast<MemberPointerType>(ty)->getPointeeType(); 1906 break; 1907 1908 case Type::ConstantArray: 1909 case Type::IncompleteArray: 1910 // Losing element qualification here is fine. 1911 type = cast<ArrayType>(ty)->getElementType(); 1912 break; 1913 1914 case Type::VariableArray: { 1915 // Losing element qualification here is fine. 1916 const VariableArrayType *vat = cast<VariableArrayType>(ty); 1917 1918 // Unknown size indication requires no size computation. 1919 // Otherwise, evaluate and record it. 1920 if (const Expr *size = vat->getSizeExpr()) { 1921 // It's possible that we might have emitted this already, 1922 // e.g. with a typedef and a pointer to it. 1923 llvm::Value *&entry = VLASizeMap[size]; 1924 if (!entry) { 1925 llvm::Value *Size = EmitScalarExpr(size); 1926 1927 // C11 6.7.6.2p5: 1928 // If the size is an expression that is not an integer constant 1929 // expression [...] each time it is evaluated it shall have a value 1930 // greater than zero. 1931 if (SanOpts.has(SanitizerKind::VLABound) && 1932 size->getType()->isSignedIntegerType()) { 1933 SanitizerScope SanScope(this); 1934 llvm::Value *Zero = llvm::Constant::getNullValue(Size->getType()); 1935 llvm::Constant *StaticArgs[] = { 1936 EmitCheckSourceLocation(size->getBeginLoc()), 1937 EmitCheckTypeDescriptor(size->getType())}; 1938 EmitCheck(std::make_pair(Builder.CreateICmpSGT(Size, Zero), 1939 SanitizerKind::VLABound), 1940 SanitizerHandler::VLABoundNotPositive, StaticArgs, Size); 1941 } 1942 1943 // Always zexting here would be wrong if it weren't 1944 // undefined behavior to have a negative bound. 1945 entry = Builder.CreateIntCast(Size, SizeTy, /*signed*/ false); 1946 } 1947 } 1948 type = vat->getElementType(); 1949 break; 1950 } 1951 1952 case Type::FunctionProto: 1953 case Type::FunctionNoProto: 1954 type = cast<FunctionType>(ty)->getReturnType(); 1955 break; 1956 1957 case Type::Paren: 1958 case Type::TypeOf: 1959 case Type::UnaryTransform: 1960 case Type::Attributed: 1961 case Type::SubstTemplateTypeParm: 1962 case Type::PackExpansion: 1963 case Type::MacroQualified: 1964 // Keep walking after single level desugaring. 1965 type = type.getSingleStepDesugaredType(getContext()); 1966 break; 1967 1968 case Type::Typedef: 1969 case Type::Decltype: 1970 case Type::Auto: 1971 case Type::DeducedTemplateSpecialization: 1972 // Stop walking: nothing to do. 1973 return; 1974 1975 case Type::TypeOfExpr: 1976 // Stop walking: emit typeof expression. 1977 EmitIgnoredExpr(cast<TypeOfExprType>(ty)->getUnderlyingExpr()); 1978 return; 1979 1980 case Type::Atomic: 1981 type = cast<AtomicType>(ty)->getValueType(); 1982 break; 1983 1984 case Type::Pipe: 1985 type = cast<PipeType>(ty)->getElementType(); 1986 break; 1987 } 1988 } while (type->isVariablyModifiedType()); 1989 } 1990 1991 Address CodeGenFunction::EmitVAListRef(const Expr* E) { 1992 if (getContext().getBuiltinVaListType()->isArrayType()) 1993 return EmitPointerWithAlignment(E); 1994 return EmitLValue(E).getAddress(); 1995 } 1996 1997 Address CodeGenFunction::EmitMSVAListRef(const Expr *E) { 1998 return EmitLValue(E).getAddress(); 1999 } 2000 2001 void CodeGenFunction::EmitDeclRefExprDbgValue(const DeclRefExpr *E, 2002 const APValue &Init) { 2003 assert(Init.hasValue() && "Invalid DeclRefExpr initializer!"); 2004 if (CGDebugInfo *Dbg = getDebugInfo()) 2005 if (CGM.getCodeGenOpts().getDebugInfo() >= codegenoptions::LimitedDebugInfo) 2006 Dbg->EmitGlobalVariable(E->getDecl(), Init); 2007 } 2008 2009 CodeGenFunction::PeepholeProtection 2010 CodeGenFunction::protectFromPeepholes(RValue rvalue) { 2011 // At the moment, the only aggressive peephole we do in IR gen 2012 // is trunc(zext) folding, but if we add more, we can easily 2013 // extend this protection. 2014 2015 if (!rvalue.isScalar()) return PeepholeProtection(); 2016 llvm::Value *value = rvalue.getScalarVal(); 2017 if (!isa<llvm::ZExtInst>(value)) return PeepholeProtection(); 2018 2019 // Just make an extra bitcast. 2020 assert(HaveInsertPoint()); 2021 llvm::Instruction *inst = new llvm::BitCastInst(value, value->getType(), "", 2022 Builder.GetInsertBlock()); 2023 2024 PeepholeProtection protection; 2025 protection.Inst = inst; 2026 return protection; 2027 } 2028 2029 void CodeGenFunction::unprotectFromPeepholes(PeepholeProtection protection) { 2030 if (!protection.Inst) return; 2031 2032 // In theory, we could try to duplicate the peepholes now, but whatever. 2033 protection.Inst->eraseFromParent(); 2034 } 2035 2036 void CodeGenFunction::EmitAlignmentAssumption(llvm::Value *PtrValue, 2037 QualType Ty, SourceLocation Loc, 2038 SourceLocation AssumptionLoc, 2039 llvm::Value *Alignment, 2040 llvm::Value *OffsetValue) { 2041 llvm::Value *TheCheck; 2042 llvm::Instruction *Assumption = Builder.CreateAlignmentAssumption( 2043 CGM.getDataLayout(), PtrValue, Alignment, OffsetValue, &TheCheck); 2044 if (SanOpts.has(SanitizerKind::Alignment)) { 2045 EmitAlignmentAssumptionCheck(PtrValue, Ty, Loc, AssumptionLoc, Alignment, 2046 OffsetValue, TheCheck, Assumption); 2047 } 2048 } 2049 2050 void CodeGenFunction::EmitAlignmentAssumption(llvm::Value *PtrValue, 2051 QualType Ty, SourceLocation Loc, 2052 SourceLocation AssumptionLoc, 2053 unsigned Alignment, 2054 llvm::Value *OffsetValue) { 2055 llvm::Value *TheCheck; 2056 llvm::Instruction *Assumption = Builder.CreateAlignmentAssumption( 2057 CGM.getDataLayout(), PtrValue, Alignment, OffsetValue, &TheCheck); 2058 if (SanOpts.has(SanitizerKind::Alignment)) { 2059 llvm::Value *AlignmentVal = llvm::ConstantInt::get(IntPtrTy, Alignment); 2060 EmitAlignmentAssumptionCheck(PtrValue, Ty, Loc, AssumptionLoc, AlignmentVal, 2061 OffsetValue, TheCheck, Assumption); 2062 } 2063 } 2064 2065 void CodeGenFunction::EmitAlignmentAssumption(llvm::Value *PtrValue, 2066 const Expr *E, 2067 SourceLocation AssumptionLoc, 2068 unsigned Alignment, 2069 llvm::Value *OffsetValue) { 2070 if (auto *CE = dyn_cast<CastExpr>(E)) 2071 E = CE->getSubExprAsWritten(); 2072 QualType Ty = E->getType(); 2073 SourceLocation Loc = E->getExprLoc(); 2074 2075 EmitAlignmentAssumption(PtrValue, Ty, Loc, AssumptionLoc, Alignment, 2076 OffsetValue); 2077 } 2078 2079 llvm::Value *CodeGenFunction::EmitAnnotationCall(llvm::Function *AnnotationFn, 2080 llvm::Value *AnnotatedVal, 2081 StringRef AnnotationStr, 2082 SourceLocation Location) { 2083 llvm::Value *Args[4] = { 2084 AnnotatedVal, 2085 Builder.CreateBitCast(CGM.EmitAnnotationString(AnnotationStr), Int8PtrTy), 2086 Builder.CreateBitCast(CGM.EmitAnnotationUnit(Location), Int8PtrTy), 2087 CGM.EmitAnnotationLineNo(Location) 2088 }; 2089 return Builder.CreateCall(AnnotationFn, Args); 2090 } 2091 2092 void CodeGenFunction::EmitVarAnnotations(const VarDecl *D, llvm::Value *V) { 2093 assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute"); 2094 // FIXME We create a new bitcast for every annotation because that's what 2095 // llvm-gcc was doing. 2096 for (const auto *I : D->specific_attrs<AnnotateAttr>()) 2097 EmitAnnotationCall(CGM.getIntrinsic(llvm::Intrinsic::var_annotation), 2098 Builder.CreateBitCast(V, CGM.Int8PtrTy, V->getName()), 2099 I->getAnnotation(), D->getLocation()); 2100 } 2101 2102 Address CodeGenFunction::EmitFieldAnnotations(const FieldDecl *D, 2103 Address Addr) { 2104 assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute"); 2105 llvm::Value *V = Addr.getPointer(); 2106 llvm::Type *VTy = V->getType(); 2107 llvm::Function *F = CGM.getIntrinsic(llvm::Intrinsic::ptr_annotation, 2108 CGM.Int8PtrTy); 2109 2110 for (const auto *I : D->specific_attrs<AnnotateAttr>()) { 2111 // FIXME Always emit the cast inst so we can differentiate between 2112 // annotation on the first field of a struct and annotation on the struct 2113 // itself. 2114 if (VTy != CGM.Int8PtrTy) 2115 V = Builder.CreateBitCast(V, CGM.Int8PtrTy); 2116 V = EmitAnnotationCall(F, V, I->getAnnotation(), D->getLocation()); 2117 V = Builder.CreateBitCast(V, VTy); 2118 } 2119 2120 return Address(V, Addr.getAlignment()); 2121 } 2122 2123 CodeGenFunction::CGCapturedStmtInfo::~CGCapturedStmtInfo() { } 2124 2125 CodeGenFunction::SanitizerScope::SanitizerScope(CodeGenFunction *CGF) 2126 : CGF(CGF) { 2127 assert(!CGF->IsSanitizerScope); 2128 CGF->IsSanitizerScope = true; 2129 } 2130 2131 CodeGenFunction::SanitizerScope::~SanitizerScope() { 2132 CGF->IsSanitizerScope = false; 2133 } 2134 2135 void CodeGenFunction::InsertHelper(llvm::Instruction *I, 2136 const llvm::Twine &Name, 2137 llvm::BasicBlock *BB, 2138 llvm::BasicBlock::iterator InsertPt) const { 2139 LoopStack.InsertHelper(I); 2140 if (IsSanitizerScope) 2141 CGM.getSanitizerMetadata()->disableSanitizerForInstruction(I); 2142 } 2143 2144 void CGBuilderInserter::InsertHelper( 2145 llvm::Instruction *I, const llvm::Twine &Name, llvm::BasicBlock *BB, 2146 llvm::BasicBlock::iterator InsertPt) const { 2147 llvm::IRBuilderDefaultInserter::InsertHelper(I, Name, BB, InsertPt); 2148 if (CGF) 2149 CGF->InsertHelper(I, Name, BB, InsertPt); 2150 } 2151 2152 static bool hasRequiredFeatures(const SmallVectorImpl<StringRef> &ReqFeatures, 2153 CodeGenModule &CGM, const FunctionDecl *FD, 2154 std::string &FirstMissing) { 2155 // If there aren't any required features listed then go ahead and return. 2156 if (ReqFeatures.empty()) 2157 return false; 2158 2159 // Now build up the set of caller features and verify that all the required 2160 // features are there. 2161 llvm::StringMap<bool> CallerFeatureMap; 2162 CGM.getFunctionFeatureMap(CallerFeatureMap, GlobalDecl().getWithDecl(FD)); 2163 2164 // If we have at least one of the features in the feature list return 2165 // true, otherwise return false. 2166 return std::all_of( 2167 ReqFeatures.begin(), ReqFeatures.end(), [&](StringRef Feature) { 2168 SmallVector<StringRef, 1> OrFeatures; 2169 Feature.split(OrFeatures, '|'); 2170 return llvm::any_of(OrFeatures, [&](StringRef Feature) { 2171 if (!CallerFeatureMap.lookup(Feature)) { 2172 FirstMissing = Feature.str(); 2173 return false; 2174 } 2175 return true; 2176 }); 2177 }); 2178 } 2179 2180 // Emits an error if we don't have a valid set of target features for the 2181 // called function. 2182 void CodeGenFunction::checkTargetFeatures(const CallExpr *E, 2183 const FunctionDecl *TargetDecl) { 2184 return checkTargetFeatures(E->getBeginLoc(), TargetDecl); 2185 } 2186 2187 // Emits an error if we don't have a valid set of target features for the 2188 // called function. 2189 void CodeGenFunction::checkTargetFeatures(SourceLocation Loc, 2190 const FunctionDecl *TargetDecl) { 2191 // Early exit if this is an indirect call. 2192 if (!TargetDecl) 2193 return; 2194 2195 // Get the current enclosing function if it exists. If it doesn't 2196 // we can't check the target features anyhow. 2197 const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(CurFuncDecl); 2198 if (!FD) 2199 return; 2200 2201 // Grab the required features for the call. For a builtin this is listed in 2202 // the td file with the default cpu, for an always_inline function this is any 2203 // listed cpu and any listed features. 2204 unsigned BuiltinID = TargetDecl->getBuiltinID(); 2205 std::string MissingFeature; 2206 if (BuiltinID) { 2207 SmallVector<StringRef, 1> ReqFeatures; 2208 const char *FeatureList = 2209 CGM.getContext().BuiltinInfo.getRequiredFeatures(BuiltinID); 2210 // Return if the builtin doesn't have any required features. 2211 if (!FeatureList || StringRef(FeatureList) == "") 2212 return; 2213 StringRef(FeatureList).split(ReqFeatures, ','); 2214 if (!hasRequiredFeatures(ReqFeatures, CGM, FD, MissingFeature)) 2215 CGM.getDiags().Report(Loc, diag::err_builtin_needs_feature) 2216 << TargetDecl->getDeclName() 2217 << CGM.getContext().BuiltinInfo.getRequiredFeatures(BuiltinID); 2218 2219 } else if (TargetDecl->hasAttr<TargetAttr>() || 2220 TargetDecl->hasAttr<CPUSpecificAttr>()) { 2221 // Get the required features for the callee. 2222 2223 const TargetAttr *TD = TargetDecl->getAttr<TargetAttr>(); 2224 TargetAttr::ParsedTargetAttr ParsedAttr = CGM.filterFunctionTargetAttrs(TD); 2225 2226 SmallVector<StringRef, 1> ReqFeatures; 2227 llvm::StringMap<bool> CalleeFeatureMap; 2228 CGM.getFunctionFeatureMap(CalleeFeatureMap, TargetDecl); 2229 2230 for (const auto &F : ParsedAttr.Features) { 2231 if (F[0] == '+' && CalleeFeatureMap.lookup(F.substr(1))) 2232 ReqFeatures.push_back(StringRef(F).substr(1)); 2233 } 2234 2235 for (const auto &F : CalleeFeatureMap) { 2236 // Only positive features are "required". 2237 if (F.getValue()) 2238 ReqFeatures.push_back(F.getKey()); 2239 } 2240 if (!hasRequiredFeatures(ReqFeatures, CGM, FD, MissingFeature)) 2241 CGM.getDiags().Report(Loc, diag::err_function_needs_feature) 2242 << FD->getDeclName() << TargetDecl->getDeclName() << MissingFeature; 2243 } 2244 } 2245 2246 void CodeGenFunction::EmitSanitizerStatReport(llvm::SanitizerStatKind SSK) { 2247 if (!CGM.getCodeGenOpts().SanitizeStats) 2248 return; 2249 2250 llvm::IRBuilder<> IRB(Builder.GetInsertBlock(), Builder.GetInsertPoint()); 2251 IRB.SetCurrentDebugLocation(Builder.getCurrentDebugLocation()); 2252 CGM.getSanStats().create(IRB, SSK); 2253 } 2254 2255 llvm::Value * 2256 CodeGenFunction::FormResolverCondition(const MultiVersionResolverOption &RO) { 2257 llvm::Value *Condition = nullptr; 2258 2259 if (!RO.Conditions.Architecture.empty()) 2260 Condition = EmitX86CpuIs(RO.Conditions.Architecture); 2261 2262 if (!RO.Conditions.Features.empty()) { 2263 llvm::Value *FeatureCond = EmitX86CpuSupports(RO.Conditions.Features); 2264 Condition = 2265 Condition ? Builder.CreateAnd(Condition, FeatureCond) : FeatureCond; 2266 } 2267 return Condition; 2268 } 2269 2270 static void CreateMultiVersionResolverReturn(CodeGenModule &CGM, 2271 llvm::Function *Resolver, 2272 CGBuilderTy &Builder, 2273 llvm::Function *FuncToReturn, 2274 bool SupportsIFunc) { 2275 if (SupportsIFunc) { 2276 Builder.CreateRet(FuncToReturn); 2277 return; 2278 } 2279 2280 llvm::SmallVector<llvm::Value *, 10> Args; 2281 llvm::for_each(Resolver->args(), 2282 [&](llvm::Argument &Arg) { Args.push_back(&Arg); }); 2283 2284 llvm::CallInst *Result = Builder.CreateCall(FuncToReturn, Args); 2285 Result->setTailCallKind(llvm::CallInst::TCK_MustTail); 2286 2287 if (Resolver->getReturnType()->isVoidTy()) 2288 Builder.CreateRetVoid(); 2289 else 2290 Builder.CreateRet(Result); 2291 } 2292 2293 void CodeGenFunction::EmitMultiVersionResolver( 2294 llvm::Function *Resolver, ArrayRef<MultiVersionResolverOption> Options) { 2295 assert((getContext().getTargetInfo().getTriple().getArch() == 2296 llvm::Triple::x86 || 2297 getContext().getTargetInfo().getTriple().getArch() == 2298 llvm::Triple::x86_64) && 2299 "Only implemented for x86 targets"); 2300 2301 bool SupportsIFunc = getContext().getTargetInfo().supportsIFunc(); 2302 2303 // Main function's basic block. 2304 llvm::BasicBlock *CurBlock = createBasicBlock("resolver_entry", Resolver); 2305 Builder.SetInsertPoint(CurBlock); 2306 EmitX86CpuInit(); 2307 2308 for (const MultiVersionResolverOption &RO : Options) { 2309 Builder.SetInsertPoint(CurBlock); 2310 llvm::Value *Condition = FormResolverCondition(RO); 2311 2312 // The 'default' or 'generic' case. 2313 if (!Condition) { 2314 assert(&RO == Options.end() - 1 && 2315 "Default or Generic case must be last"); 2316 CreateMultiVersionResolverReturn(CGM, Resolver, Builder, RO.Function, 2317 SupportsIFunc); 2318 return; 2319 } 2320 2321 llvm::BasicBlock *RetBlock = createBasicBlock("resolver_return", Resolver); 2322 CGBuilderTy RetBuilder(*this, RetBlock); 2323 CreateMultiVersionResolverReturn(CGM, Resolver, RetBuilder, RO.Function, 2324 SupportsIFunc); 2325 CurBlock = createBasicBlock("resolver_else", Resolver); 2326 Builder.CreateCondBr(Condition, RetBlock, CurBlock); 2327 } 2328 2329 // If no generic/default, emit an unreachable. 2330 Builder.SetInsertPoint(CurBlock); 2331 llvm::CallInst *TrapCall = EmitTrapCall(llvm::Intrinsic::trap); 2332 TrapCall->setDoesNotReturn(); 2333 TrapCall->setDoesNotThrow(); 2334 Builder.CreateUnreachable(); 2335 Builder.ClearInsertionPoint(); 2336 } 2337 2338 // Loc - where the diagnostic will point, where in the source code this 2339 // alignment has failed. 2340 // SecondaryLoc - if present (will be present if sufficiently different from 2341 // Loc), the diagnostic will additionally point a "Note:" to this location. 2342 // It should be the location where the __attribute__((assume_aligned)) 2343 // was written e.g. 2344 void CodeGenFunction::EmitAlignmentAssumptionCheck( 2345 llvm::Value *Ptr, QualType Ty, SourceLocation Loc, 2346 SourceLocation SecondaryLoc, llvm::Value *Alignment, 2347 llvm::Value *OffsetValue, llvm::Value *TheCheck, 2348 llvm::Instruction *Assumption) { 2349 assert(Assumption && isa<llvm::CallInst>(Assumption) && 2350 cast<llvm::CallInst>(Assumption)->getCalledValue() == 2351 llvm::Intrinsic::getDeclaration( 2352 Builder.GetInsertBlock()->getParent()->getParent(), 2353 llvm::Intrinsic::assume) && 2354 "Assumption should be a call to llvm.assume()."); 2355 assert(&(Builder.GetInsertBlock()->back()) == Assumption && 2356 "Assumption should be the last instruction of the basic block, " 2357 "since the basic block is still being generated."); 2358 2359 if (!SanOpts.has(SanitizerKind::Alignment)) 2360 return; 2361 2362 // Don't check pointers to volatile data. The behavior here is implementation- 2363 // defined. 2364 if (Ty->getPointeeType().isVolatileQualified()) 2365 return; 2366 2367 // We need to temorairly remove the assumption so we can insert the 2368 // sanitizer check before it, else the check will be dropped by optimizations. 2369 Assumption->removeFromParent(); 2370 2371 { 2372 SanitizerScope SanScope(this); 2373 2374 if (!OffsetValue) 2375 OffsetValue = Builder.getInt1(0); // no offset. 2376 2377 llvm::Constant *StaticData[] = {EmitCheckSourceLocation(Loc), 2378 EmitCheckSourceLocation(SecondaryLoc), 2379 EmitCheckTypeDescriptor(Ty)}; 2380 llvm::Value *DynamicData[] = {EmitCheckValue(Ptr), 2381 EmitCheckValue(Alignment), 2382 EmitCheckValue(OffsetValue)}; 2383 EmitCheck({std::make_pair(TheCheck, SanitizerKind::Alignment)}, 2384 SanitizerHandler::AlignmentAssumption, StaticData, DynamicData); 2385 } 2386 2387 // We are now in the (new, empty) "cont" basic block. 2388 // Reintroduce the assumption. 2389 Builder.Insert(Assumption); 2390 // FIXME: Assumption still has it's original basic block as it's Parent. 2391 } 2392 2393 llvm::DebugLoc CodeGenFunction::SourceLocToDebugLoc(SourceLocation Location) { 2394 if (CGDebugInfo *DI = getDebugInfo()) 2395 return DI->SourceLocToDebugLoc(Location); 2396 2397 return llvm::DebugLoc(); 2398 } 2399