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Diffstat (limited to 'gnu/llvm/clang/lib/CodeGen/CodeGenFunction.cpp')
| -rw-r--r-- | gnu/llvm/clang/lib/CodeGen/CodeGenFunction.cpp | 2495 |
1 files changed, 2495 insertions, 0 deletions
diff --git a/gnu/llvm/clang/lib/CodeGen/CodeGenFunction.cpp b/gnu/llvm/clang/lib/CodeGen/CodeGenFunction.cpp new file mode 100644 index 00000000000..648e6d9c214 --- /dev/null +++ b/gnu/llvm/clang/lib/CodeGen/CodeGenFunction.cpp @@ -0,0 +1,2495 @@ +//===--- CodeGenFunction.cpp - Emit LLVM Code from ASTs for a Function ----===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This coordinates the per-function state used while generating code. +// +//===----------------------------------------------------------------------===// + +#include "CodeGenFunction.h" +#include "CGBlocks.h" +#include "CGCUDARuntime.h" +#include "CGCXXABI.h" +#include "CGCleanup.h" +#include "CGDebugInfo.h" +#include "CGOpenMPRuntime.h" +#include "CodeGenModule.h" +#include "CodeGenPGO.h" +#include "TargetInfo.h" +#include "clang/AST/ASTContext.h" +#include "clang/AST/ASTLambda.h" +#include "clang/AST/Attr.h" +#include "clang/AST/Decl.h" +#include "clang/AST/DeclCXX.h" +#include "clang/AST/StmtCXX.h" +#include "clang/AST/StmtObjC.h" +#include "clang/Basic/Builtins.h" +#include "clang/Basic/CodeGenOptions.h" +#include "clang/Basic/TargetInfo.h" +#include "clang/CodeGen/CGFunctionInfo.h" +#include "clang/Frontend/FrontendDiagnostic.h" +#include "llvm/IR/DataLayout.h" +#include "llvm/IR/Dominators.h" +#include "llvm/IR/FPEnv.h" +#include "llvm/IR/IntrinsicInst.h" +#include "llvm/IR/Intrinsics.h" +#include "llvm/IR/MDBuilder.h" +#include "llvm/IR/Operator.h" +#include "llvm/Transforms/Utils/PromoteMemToReg.h" +using namespace clang; +using namespace CodeGen; + +/// shouldEmitLifetimeMarkers - Decide whether we need emit the life-time +/// markers. +static bool shouldEmitLifetimeMarkers(const CodeGenOptions &CGOpts, + const LangOptions &LangOpts) { + if (CGOpts.DisableLifetimeMarkers) + return false; + + // Sanitizers may use markers. + if (CGOpts.SanitizeAddressUseAfterScope || + LangOpts.Sanitize.has(SanitizerKind::HWAddress) || + LangOpts.Sanitize.has(SanitizerKind::Memory)) + return true; + + // For now, only in optimized builds. + return CGOpts.OptimizationLevel != 0; +} + +CodeGenFunction::CodeGenFunction(CodeGenModule &cgm, bool suppressNewContext) + : CodeGenTypeCache(cgm), CGM(cgm), Target(cgm.getTarget()), + Builder(cgm, cgm.getModule().getContext(), llvm::ConstantFolder(), + CGBuilderInserterTy(this)), + SanOpts(CGM.getLangOpts().Sanitize), DebugInfo(CGM.getModuleDebugInfo()), + PGO(cgm), ShouldEmitLifetimeMarkers(shouldEmitLifetimeMarkers( + CGM.getCodeGenOpts(), CGM.getLangOpts())) { + if (!suppressNewContext) + CGM.getCXXABI().getMangleContext().startNewFunction(); + + llvm::FastMathFlags FMF; + if (CGM.getLangOpts().FastMath) + FMF.setFast(); + if (CGM.getLangOpts().FiniteMathOnly) { + FMF.setNoNaNs(); + FMF.setNoInfs(); + } + if (CGM.getCodeGenOpts().NoNaNsFPMath) { + FMF.setNoNaNs(); + } + if (CGM.getCodeGenOpts().NoSignedZeros) { + FMF.setNoSignedZeros(); + } + if (CGM.getCodeGenOpts().ReciprocalMath) { + FMF.setAllowReciprocal(); + } + if (CGM.getCodeGenOpts().Reassociate) { + FMF.setAllowReassoc(); + } + Builder.setFastMathFlags(FMF); + SetFPModel(); +} + +CodeGenFunction::~CodeGenFunction() { + assert(LifetimeExtendedCleanupStack.empty() && "failed to emit a cleanup"); + + // If there are any unclaimed block infos, go ahead and destroy them + // now. This can happen if IR-gen gets clever and skips evaluating + // something. + if (FirstBlockInfo) + destroyBlockInfos(FirstBlockInfo); + + if (getLangOpts().OpenMP && CurFn) + CGM.getOpenMPRuntime().functionFinished(*this); +} + +// Map the LangOption for rounding mode into +// the corresponding enum in the IR. +static llvm::fp::RoundingMode ToConstrainedRoundingMD( + LangOptions::FPRoundingModeKind Kind) { + + switch (Kind) { + case LangOptions::FPR_ToNearest: return llvm::fp::rmToNearest; + case LangOptions::FPR_Downward: return llvm::fp::rmDownward; + case LangOptions::FPR_Upward: return llvm::fp::rmUpward; + case LangOptions::FPR_TowardZero: return llvm::fp::rmTowardZero; + case LangOptions::FPR_Dynamic: return llvm::fp::rmDynamic; + } + llvm_unreachable("Unsupported FP RoundingMode"); +} + +// Map the LangOption for exception behavior into +// the corresponding enum in the IR. +static llvm::fp::ExceptionBehavior ToConstrainedExceptMD( + LangOptions::FPExceptionModeKind Kind) { + + switch (Kind) { + case LangOptions::FPE_Ignore: return llvm::fp::ebIgnore; + case LangOptions::FPE_MayTrap: return llvm::fp::ebMayTrap; + case LangOptions::FPE_Strict: return llvm::fp::ebStrict; + } + llvm_unreachable("Unsupported FP Exception Behavior"); +} + +void CodeGenFunction::SetFPModel() { + auto fpRoundingMode = ToConstrainedRoundingMD( + getLangOpts().getFPRoundingMode()); + auto fpExceptionBehavior = ToConstrainedExceptMD( + getLangOpts().getFPExceptionMode()); + + if (fpExceptionBehavior == llvm::fp::ebIgnore && + fpRoundingMode == llvm::fp::rmToNearest) + // Constrained intrinsics are not used. + ; + else { + Builder.setIsFPConstrained(true); + Builder.setDefaultConstrainedRounding(fpRoundingMode); + Builder.setDefaultConstrainedExcept(fpExceptionBehavior); + } +} + +CharUnits CodeGenFunction::getNaturalPointeeTypeAlignment(QualType T, + LValueBaseInfo *BaseInfo, + TBAAAccessInfo *TBAAInfo) { + return getNaturalTypeAlignment(T->getPointeeType(), BaseInfo, TBAAInfo, + /* forPointeeType= */ true); +} + +CharUnits CodeGenFunction::getNaturalTypeAlignment(QualType T, + LValueBaseInfo *BaseInfo, + TBAAAccessInfo *TBAAInfo, + bool forPointeeType) { + if (TBAAInfo) + *TBAAInfo = CGM.getTBAAAccessInfo(T); + + // Honor alignment typedef attributes even on incomplete types. + // We also honor them straight for C++ class types, even as pointees; + // there's an expressivity gap here. + if (auto TT = T->getAs<TypedefType>()) { + if (auto Align = TT->getDecl()->getMaxAlignment()) { + if (BaseInfo) + *BaseInfo = LValueBaseInfo(AlignmentSource::AttributedType); + return getContext().toCharUnitsFromBits(Align); + } + } + + if (BaseInfo) + *BaseInfo = LValueBaseInfo(AlignmentSource::Type); + + CharUnits Alignment; + if (T->isIncompleteType()) { + Alignment = CharUnits::One(); // Shouldn't be used, but pessimistic is best. + } else { + // For C++ class pointees, we don't know whether we're pointing at a + // base or a complete object, so we generally need to use the + // non-virtual alignment. + const CXXRecordDecl *RD; + if (forPointeeType && (RD = T->getAsCXXRecordDecl())) { + Alignment = CGM.getClassPointerAlignment(RD); + } else { + Alignment = getContext().getTypeAlignInChars(T); + if (T.getQualifiers().hasUnaligned()) + Alignment = CharUnits::One(); + } + + // Cap to the global maximum type alignment unless the alignment + // was somehow explicit on the type. + if (unsigned MaxAlign = getLangOpts().MaxTypeAlign) { + if (Alignment.getQuantity() > MaxAlign && + !getContext().isAlignmentRequired(T)) + Alignment = CharUnits::fromQuantity(MaxAlign); + } + } + return Alignment; +} + +LValue CodeGenFunction::MakeNaturalAlignAddrLValue(llvm::Value *V, QualType T) { + LValueBaseInfo BaseInfo; + TBAAAccessInfo TBAAInfo; + CharUnits Alignment = getNaturalTypeAlignment(T, &BaseInfo, &TBAAInfo); + return LValue::MakeAddr(Address(V, Alignment), T, getContext(), BaseInfo, + TBAAInfo); +} + +/// Given a value of type T* that may not be to a complete object, +/// construct an l-value with the natural pointee alignment of T. +LValue +CodeGenFunction::MakeNaturalAlignPointeeAddrLValue(llvm::Value *V, QualType T) { + LValueBaseInfo BaseInfo; + TBAAAccessInfo TBAAInfo; + CharUnits Align = getNaturalTypeAlignment(T, &BaseInfo, &TBAAInfo, + /* forPointeeType= */ true); + return MakeAddrLValue(Address(V, Align), T, BaseInfo, TBAAInfo); +} + + +llvm::Type *CodeGenFunction::ConvertTypeForMem(QualType T) { + return CGM.getTypes().ConvertTypeForMem(T); +} + +llvm::Type *CodeGenFunction::ConvertType(QualType T) { + return CGM.getTypes().ConvertType(T); +} + +TypeEvaluationKind CodeGenFunction::getEvaluationKind(QualType type) { + type = type.getCanonicalType(); + while (true) { + switch (type->getTypeClass()) { +#define TYPE(name, parent) +#define ABSTRACT_TYPE(name, parent) +#define NON_CANONICAL_TYPE(name, parent) case Type::name: +#define DEPENDENT_TYPE(name, parent) case Type::name: +#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(name, parent) case Type::name: +#include "clang/AST/TypeNodes.inc" + llvm_unreachable("non-canonical or dependent type in IR-generation"); + + case Type::Auto: + case Type::DeducedTemplateSpecialization: + llvm_unreachable("undeduced type in IR-generation"); + + // Various scalar types. + case Type::Builtin: + case Type::Pointer: + case Type::BlockPointer: + case Type::LValueReference: + case Type::RValueReference: + case Type::MemberPointer: + case Type::Vector: + case Type::ExtVector: + case Type::FunctionProto: + case Type::FunctionNoProto: + case Type::Enum: + case Type::ObjCObjectPointer: + case Type::Pipe: + return TEK_Scalar; + + // Complexes. + case Type::Complex: + return TEK_Complex; + + // Arrays, records, and Objective-C objects. + case Type::ConstantArray: + case Type::IncompleteArray: + case Type::VariableArray: + case Type::Record: + case Type::ObjCObject: + case Type::ObjCInterface: + return TEK_Aggregate; + + // We operate on atomic values according to their underlying type. + case Type::Atomic: + type = cast<AtomicType>(type)->getValueType(); + continue; + } + llvm_unreachable("unknown type kind!"); + } +} + +llvm::DebugLoc CodeGenFunction::EmitReturnBlock() { + // For cleanliness, we try to avoid emitting the return block for + // simple cases. + llvm::BasicBlock *CurBB = Builder.GetInsertBlock(); + + if (CurBB) { + assert(!CurBB->getTerminator() && "Unexpected terminated block."); + + // We have a valid insert point, reuse it if it is empty or there are no + // explicit jumps to the return block. + if (CurBB->empty() || ReturnBlock.getBlock()->use_empty()) { + ReturnBlock.getBlock()->replaceAllUsesWith(CurBB); + delete ReturnBlock.getBlock(); + ReturnBlock = JumpDest(); + } else + EmitBlock(ReturnBlock.getBlock()); + return llvm::DebugLoc(); + } + + // Otherwise, if the return block is the target of a single direct + // branch then we can just put the code in that block instead. This + // cleans up functions which started with a unified return block. + if (ReturnBlock.getBlock()->hasOneUse()) { + llvm::BranchInst *BI = + dyn_cast<llvm::BranchInst>(*ReturnBlock.getBlock()->user_begin()); + if (BI && BI->isUnconditional() && + BI->getSuccessor(0) == ReturnBlock.getBlock()) { + // Record/return the DebugLoc of the simple 'return' expression to be used + // later by the actual 'ret' instruction. + llvm::DebugLoc Loc = BI->getDebugLoc(); + Builder.SetInsertPoint(BI->getParent()); + BI->eraseFromParent(); + delete ReturnBlock.getBlock(); + ReturnBlock = JumpDest(); + return Loc; + } + } + + // FIXME: We are at an unreachable point, there is no reason to emit the block + // unless it has uses. However, we still need a place to put the debug + // region.end for now. + + EmitBlock(ReturnBlock.getBlock()); + return llvm::DebugLoc(); +} + +static void EmitIfUsed(CodeGenFunction &CGF, llvm::BasicBlock *BB) { + if (!BB) return; + if (!BB->use_empty()) + return CGF.CurFn->getBasicBlockList().push_back(BB); + delete BB; +} + +void CodeGenFunction::FinishFunction(SourceLocation EndLoc) { + assert(BreakContinueStack.empty() && + "mismatched push/pop in break/continue stack!"); + + bool OnlySimpleReturnStmts = NumSimpleReturnExprs > 0 + && NumSimpleReturnExprs == NumReturnExprs + && ReturnBlock.getBlock()->use_empty(); + // Usually the return expression is evaluated before the cleanup + // code. If the function contains only a simple return statement, + // such as a constant, the location before the cleanup code becomes + // the last useful breakpoint in the function, because the simple + // return expression will be evaluated after the cleanup code. To be + // safe, set the debug location for cleanup code to the location of + // the return statement. Otherwise the cleanup code should be at the + // end of the function's lexical scope. + // + // If there are multiple branches to the return block, the branch + // instructions will get the location of the return statements and + // all will be fine. + if (CGDebugInfo *DI = getDebugInfo()) { + if (OnlySimpleReturnStmts) + DI->EmitLocation(Builder, LastStopPoint); + else + DI->EmitLocation(Builder, EndLoc); + } + + // Pop any cleanups that might have been associated with the + // parameters. Do this in whatever block we're currently in; it's + // important to do this before we enter the return block or return + // edges will be *really* confused. + bool HasCleanups = EHStack.stable_begin() != PrologueCleanupDepth; + bool HasOnlyLifetimeMarkers = + HasCleanups && EHStack.containsOnlyLifetimeMarkers(PrologueCleanupDepth); + bool EmitRetDbgLoc = !HasCleanups || HasOnlyLifetimeMarkers; + if (HasCleanups) { + // Make sure the line table doesn't jump back into the body for + // the ret after it's been at EndLoc. + Optional<ApplyDebugLocation> AL; + if (CGDebugInfo *DI = getDebugInfo()) { + if (OnlySimpleReturnStmts) + DI->EmitLocation(Builder, EndLoc); + else + // We may not have a valid end location. Try to apply it anyway, and + // fall back to an artificial location if needed. + AL = ApplyDebugLocation::CreateDefaultArtificial(*this, EndLoc); + } + + PopCleanupBlocks(PrologueCleanupDepth); + } + + // Emit function epilog (to return). + llvm::DebugLoc Loc = EmitReturnBlock(); + + if (ShouldInstrumentFunction()) { + if (CGM.getCodeGenOpts().InstrumentFunctions) + CurFn->addFnAttr("instrument-function-exit", "__cyg_profile_func_exit"); + if (CGM.getCodeGenOpts().InstrumentFunctionsAfterInlining) + CurFn->addFnAttr("instrument-function-exit-inlined", + "__cyg_profile_func_exit"); + } + + // Emit debug descriptor for function end. + if (CGDebugInfo *DI = getDebugInfo()) + DI->EmitFunctionEnd(Builder, CurFn); + + // Reset the debug location to that of the simple 'return' expression, if any + // rather than that of the end of the function's scope '}'. + ApplyDebugLocation AL(*this, Loc); + EmitFunctionEpilog(*CurFnInfo, EmitRetDbgLoc, EndLoc); + EmitEndEHSpec(CurCodeDecl); + + assert(EHStack.empty() && + "did not remove all scopes from cleanup stack!"); + + // If someone did an indirect goto, emit the indirect goto block at the end of + // the function. + if (IndirectBranch) { + EmitBlock(IndirectBranch->getParent()); + Builder.ClearInsertionPoint(); + } + + // If some of our locals escaped, insert a call to llvm.localescape in the + // entry block. + if (!EscapedLocals.empty()) { + // Invert the map from local to index into a simple vector. There should be + // no holes. + SmallVector<llvm::Value *, 4> EscapeArgs; + EscapeArgs.resize(EscapedLocals.size()); + for (auto &Pair : EscapedLocals) + EscapeArgs[Pair.second] = Pair.first; + llvm::Function *FrameEscapeFn = llvm::Intrinsic::getDeclaration( + &CGM.getModule(), llvm::Intrinsic::localescape); + CGBuilderTy(*this, AllocaInsertPt).CreateCall(FrameEscapeFn, EscapeArgs); + } + + // Remove the AllocaInsertPt instruction, which is just a convenience for us. + llvm::Instruction *Ptr = AllocaInsertPt; + AllocaInsertPt = nullptr; + Ptr->eraseFromParent(); + + // If someone took the address of a label but never did an indirect goto, we + // made a zero entry PHI node, which is illegal, zap it now. + if (IndirectBranch) { + llvm::PHINode *PN = cast<llvm::PHINode>(IndirectBranch->getAddress()); + if (PN->getNumIncomingValues() == 0) { + PN->replaceAllUsesWith(llvm::UndefValue::get(PN->getType())); + PN->eraseFromParent(); + } + } + + EmitIfUsed(*this, EHResumeBlock); + EmitIfUsed(*this, TerminateLandingPad); + EmitIfUsed(*this, TerminateHandler); + EmitIfUsed(*this, UnreachableBlock); + + for (const auto &FuncletAndParent : TerminateFunclets) + EmitIfUsed(*this, FuncletAndParent.second); + + if (CGM.getCodeGenOpts().EmitDeclMetadata) + EmitDeclMetadata(); + + for (SmallVectorImpl<std::pair<llvm::Instruction *, llvm::Value *> >::iterator + I = DeferredReplacements.begin(), + E = DeferredReplacements.end(); + I != E; ++I) { + I->first->replaceAllUsesWith(I->second); + I->first->eraseFromParent(); + } + + // Eliminate CleanupDestSlot alloca by replacing it with SSA values and + // PHIs if the current function is a coroutine. We don't do it for all + // functions as it may result in slight increase in numbers of instructions + // if compiled with no optimizations. We do it for coroutine as the lifetime + // of CleanupDestSlot alloca make correct coroutine frame building very + // difficult. + if (NormalCleanupDest.isValid() && isCoroutine()) { + llvm::DominatorTree DT(*CurFn); + llvm::PromoteMemToReg( + cast<llvm::AllocaInst>(NormalCleanupDest.getPointer()), DT); + NormalCleanupDest = Address::invalid(); + } + + // Scan function arguments for vector width. + for (llvm::Argument &A : CurFn->args()) + if (auto *VT = dyn_cast<llvm::VectorType>(A.getType())) + LargestVectorWidth = std::max((uint64_t)LargestVectorWidth, + VT->getPrimitiveSizeInBits().getFixedSize()); + + // Update vector width based on return type. + if (auto *VT = dyn_cast<llvm::VectorType>(CurFn->getReturnType())) + LargestVectorWidth = std::max((uint64_t)LargestVectorWidth, + VT->getPrimitiveSizeInBits().getFixedSize()); + + // Add the required-vector-width attribute. This contains the max width from: + // 1. min-vector-width attribute used in the source program. + // 2. Any builtins used that have a vector width specified. + // 3. Values passed in and out of inline assembly. + // 4. Width of vector arguments and return types for this function. + // 5. Width of vector aguments and return types for functions called by this + // function. + CurFn->addFnAttr("min-legal-vector-width", llvm::utostr(LargestVectorWidth)); + + // If we generated an unreachable return block, delete it now. + if (ReturnBlock.isValid() && ReturnBlock.getBlock()->use_empty()) { + Builder.ClearInsertionPoint(); + ReturnBlock.getBlock()->eraseFromParent(); + } + if (ReturnValue.isValid()) { + auto *RetAlloca = dyn_cast<llvm::AllocaInst>(ReturnValue.getPointer()); + if (RetAlloca && RetAlloca->use_empty()) { + RetAlloca->eraseFromParent(); + ReturnValue = Address::invalid(); + } + } +} + +/// ShouldInstrumentFunction - Return true if the current function should be +/// instrumented with __cyg_profile_func_* calls +bool CodeGenFunction::ShouldInstrumentFunction() { + if (!CGM.getCodeGenOpts().InstrumentFunctions && + !CGM.getCodeGenOpts().InstrumentFunctionsAfterInlining && + !CGM.getCodeGenOpts().InstrumentFunctionEntryBare) + return false; + if (!CurFuncDecl || CurFuncDecl->hasAttr<NoInstrumentFunctionAttr>()) + return false; + return true; +} + +/// ShouldXRayInstrument - Return true if the current function should be +/// instrumented with XRay nop sleds. +bool CodeGenFunction::ShouldXRayInstrumentFunction() const { + return CGM.getCodeGenOpts().XRayInstrumentFunctions; +} + +/// AlwaysEmitXRayCustomEvents - Return true if we should emit IR for calls to +/// the __xray_customevent(...) builtin calls, when doing XRay instrumentation. +bool CodeGenFunction::AlwaysEmitXRayCustomEvents() const { + return CGM.getCodeGenOpts().XRayInstrumentFunctions && + (CGM.getCodeGenOpts().XRayAlwaysEmitCustomEvents || + CGM.getCodeGenOpts().XRayInstrumentationBundle.Mask == + XRayInstrKind::Custom); +} + +bool CodeGenFunction::AlwaysEmitXRayTypedEvents() const { + return CGM.getCodeGenOpts().XRayInstrumentFunctions && + (CGM.getCodeGenOpts().XRayAlwaysEmitTypedEvents || + CGM.getCodeGenOpts().XRayInstrumentationBundle.Mask == + XRayInstrKind::Typed); +} + +llvm::Constant * +CodeGenFunction::EncodeAddrForUseInPrologue(llvm::Function *F, + llvm::Constant *Addr) { + // Addresses stored in prologue data can't require run-time fixups and must + // be PC-relative. Run-time fixups are undesirable because they necessitate + // writable text segments, which are unsafe. And absolute addresses are + // undesirable because they break PIE mode. + + // Add a layer of indirection through a private global. Taking its address + // won't result in a run-time fixup, even if Addr has linkonce_odr linkage. + auto *GV = new llvm::GlobalVariable(CGM.getModule(), Addr->getType(), + /*isConstant=*/true, + llvm::GlobalValue::PrivateLinkage, Addr); + + // Create a PC-relative address. + auto *GOTAsInt = llvm::ConstantExpr::getPtrToInt(GV, IntPtrTy); + auto *FuncAsInt = llvm::ConstantExpr::getPtrToInt(F, IntPtrTy); + auto *PCRelAsInt = llvm::ConstantExpr::getSub(GOTAsInt, FuncAsInt); + return (IntPtrTy == Int32Ty) + ? PCRelAsInt + : llvm::ConstantExpr::getTrunc(PCRelAsInt, Int32Ty); +} + +llvm::Value * +CodeGenFunction::DecodeAddrUsedInPrologue(llvm::Value *F, + llvm::Value *EncodedAddr) { + // Reconstruct the address of the global. + auto *PCRelAsInt = Builder.CreateSExt(EncodedAddr, IntPtrTy); + auto *FuncAsInt = Builder.CreatePtrToInt(F, IntPtrTy, "func_addr.int"); + auto *GOTAsInt = Builder.CreateAdd(PCRelAsInt, FuncAsInt, "global_addr.int"); + auto *GOTAddr = Builder.CreateIntToPtr(GOTAsInt, Int8PtrPtrTy, "global_addr"); + + // Load the original pointer through the global. + return Builder.CreateLoad(Address(GOTAddr, getPointerAlign()), + "decoded_addr"); +} + +void CodeGenFunction::EmitOpenCLKernelMetadata(const FunctionDecl *FD, + llvm::Function *Fn) +{ + if (!FD->hasAttr<OpenCLKernelAttr>()) + return; + + llvm::LLVMContext &Context = getLLVMContext(); + + CGM.GenOpenCLArgMetadata(Fn, FD, this); + + if (const VecTypeHintAttr *A = FD->getAttr<VecTypeHintAttr>()) { + QualType HintQTy = A->getTypeHint(); + const ExtVectorType *HintEltQTy = HintQTy->getAs<ExtVectorType>(); + bool IsSignedInteger = + HintQTy->isSignedIntegerType() || + (HintEltQTy && HintEltQTy->getElementType()->isSignedIntegerType()); + llvm::Metadata *AttrMDArgs[] = { + llvm::ConstantAsMetadata::get(llvm::UndefValue::get( + CGM.getTypes().ConvertType(A->getTypeHint()))), + llvm::ConstantAsMetadata::get(llvm::ConstantInt::get( + llvm::IntegerType::get(Context, 32), + llvm::APInt(32, (uint64_t)(IsSignedInteger ? 1 : 0))))}; + Fn->setMetadata("vec_type_hint", llvm::MDNode::get(Context, AttrMDArgs)); + } + + if (const WorkGroupSizeHintAttr *A = FD->getAttr<WorkGroupSizeHintAttr>()) { + llvm::Metadata *AttrMDArgs[] = { + llvm::ConstantAsMetadata::get(Builder.getInt32(A->getXDim())), + llvm::ConstantAsMetadata::get(Builder.getInt32(A->getYDim())), + llvm::ConstantAsMetadata::get(Builder.getInt32(A->getZDim()))}; + Fn->setMetadata("work_group_size_hint", llvm::MDNode::get(Context, AttrMDArgs)); + } + + if (const ReqdWorkGroupSizeAttr *A = FD->getAttr<ReqdWorkGroupSizeAttr>()) { + llvm::Metadata *AttrMDArgs[] = { + llvm::ConstantAsMetadata::get(Builder.getInt32(A->getXDim())), + llvm::ConstantAsMetadata::get(Builder.getInt32(A->getYDim())), + llvm::ConstantAsMetadata::get(Builder.getInt32(A->getZDim()))}; + Fn->setMetadata("reqd_work_group_size", llvm::MDNode::get(Context, AttrMDArgs)); + } + + if (const OpenCLIntelReqdSubGroupSizeAttr *A = + FD->getAttr<OpenCLIntelReqdSubGroupSizeAttr>()) { + llvm::Metadata *AttrMDArgs[] = { + llvm::ConstantAsMetadata::get(Builder.getInt32(A->getSubGroupSize()))}; + Fn->setMetadata("intel_reqd_sub_group_size", + llvm::MDNode::get(Context, AttrMDArgs)); + } +} + +/// Determine whether the function F ends with a return stmt. +static bool endsWithReturn(const Decl* F) { + const Stmt *Body = nullptr; + if (auto *FD = dyn_cast_or_null<FunctionDecl>(F)) + Body = FD->getBody(); + else if (auto *OMD = dyn_cast_or_null<ObjCMethodDecl>(F)) + Body = OMD->getBody(); + + if (auto *CS = dyn_cast_or_null<CompoundStmt>(Body)) { + auto LastStmt = CS->body_rbegin(); + if (LastStmt != CS->body_rend()) + return isa<ReturnStmt>(*LastStmt); + } + return false; +} + +void CodeGenFunction::markAsIgnoreThreadCheckingAtRuntime(llvm::Function *Fn) { + if (SanOpts.has(SanitizerKind::Thread)) { + Fn->addFnAttr("sanitize_thread_no_checking_at_run_time"); + Fn->removeFnAttr(llvm::Attribute::SanitizeThread); + } +} + +/// Check if the return value of this function requires sanitization. +bool CodeGenFunction::requiresReturnValueCheck() const { + return requiresReturnValueNullabilityCheck() || + (SanOpts.has(SanitizerKind::ReturnsNonnullAttribute) && CurCodeDecl && + CurCodeDecl->getAttr<ReturnsNonNullAttr>()); +} + +static bool matchesStlAllocatorFn(const Decl *D, const ASTContext &Ctx) { + auto *MD = dyn_cast_or_null<CXXMethodDecl>(D); + if (!MD || !MD->getDeclName().getAsIdentifierInfo() || + !MD->getDeclName().getAsIdentifierInfo()->isStr("allocate") || + (MD->getNumParams() != 1 && MD->getNumParams() != 2)) + return false; + + if (MD->parameters()[0]->getType().getCanonicalType() != Ctx.getSizeType()) + return false; + + if (MD->getNumParams() == 2) { + auto *PT = MD->parameters()[1]->getType()->getAs<PointerType>(); + if (!PT || !PT->isVoidPointerType() || + !PT->getPointeeType().isConstQualified()) + return false; + } + + return true; +} + +/// Return the UBSan prologue signature for \p FD if one is available. +static llvm::Constant *getPrologueSignature(CodeGenModule &CGM, + const FunctionDecl *FD) { + if (const auto *MD = dyn_cast<CXXMethodDecl>(FD)) + if (!MD->isStatic()) + return nullptr; + return CGM.getTargetCodeGenInfo().getUBSanFunctionSignature(CGM); +} + +void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy, + llvm::Function *Fn, + const CGFunctionInfo &FnInfo, + const FunctionArgList &Args, + SourceLocation Loc, + SourceLocation StartLoc) { + assert(!CurFn && + "Do not use a CodeGenFunction object for more than one function"); + + const Decl *D = GD.getDecl(); + + DidCallStackSave = false; + CurCodeDecl = D; + if (const auto *FD = dyn_cast_or_null<FunctionDecl>(D)) + if (FD->usesSEHTry()) + CurSEHParent = FD; + CurFuncDecl = (D ? D->getNonClosureContext() : nullptr); + FnRetTy = RetTy; + CurFn = Fn; + CurFnInfo = &FnInfo; + assert(CurFn->isDeclaration() && "Function already has body?"); + + // If this function has been blacklisted for any of the enabled sanitizers, + // disable the sanitizer for the function. + do { +#define SANITIZER(NAME, ID) \ + if (SanOpts.empty()) \ + break; \ + if (SanOpts.has(SanitizerKind::ID)) \ + if (CGM.isInSanitizerBlacklist(SanitizerKind::ID, Fn, Loc)) \ + SanOpts.set(SanitizerKind::ID, false); + +#include "clang/Basic/Sanitizers.def" +#undef SANITIZER + } while (0); + + if (D) { + // Apply the no_sanitize* attributes to SanOpts. + for (auto Attr : D->specific_attrs<NoSanitizeAttr>()) { + SanitizerMask mask = Attr->getMask(); + SanOpts.Mask &= ~mask; + if (mask & SanitizerKind::Address) + SanOpts.set(SanitizerKind::KernelAddress, false); + if (mask & SanitizerKind::KernelAddress) + SanOpts.set(SanitizerKind::Address, false); + if (mask & SanitizerKind::HWAddress) + SanOpts.set(SanitizerKind::KernelHWAddress, false); + if (mask & SanitizerKind::KernelHWAddress) + SanOpts.set(SanitizerKind::HWAddress, false); + } + } + + // Apply sanitizer attributes to the function. + if (SanOpts.hasOneOf(SanitizerKind::Address | SanitizerKind::KernelAddress)) + Fn->addFnAttr(llvm::Attribute::SanitizeAddress); + if (SanOpts.hasOneOf(SanitizerKind::HWAddress | SanitizerKind::KernelHWAddress)) + Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress); + if (SanOpts.has(SanitizerKind::MemTag)) + Fn->addFnAttr(llvm::Attribute::SanitizeMemTag); + if (SanOpts.has(SanitizerKind::Thread)) + Fn->addFnAttr(llvm::Attribute::SanitizeThread); + if (SanOpts.hasOneOf(SanitizerKind::Memory | SanitizerKind::KernelMemory)) + Fn->addFnAttr(llvm::Attribute::SanitizeMemory); + if (SanOpts.has(SanitizerKind::SafeStack)) + Fn->addFnAttr(llvm::Attribute::SafeStack); + if (SanOpts.has(SanitizerKind::ShadowCallStack)) + Fn->addFnAttr(llvm::Attribute::ShadowCallStack); + + // Apply fuzzing attribute to the function. + if (SanOpts.hasOneOf(SanitizerKind::Fuzzer | SanitizerKind::FuzzerNoLink)) + Fn->addFnAttr(llvm::Attribute::OptForFuzzing); + + // Ignore TSan memory acesses from within ObjC/ObjC++ dealloc, initialize, + // .cxx_destruct, __destroy_helper_block_ and all of their calees at run time. + if (SanOpts.has(SanitizerKind::Thread)) { + if (const auto *OMD = dyn_cast_or_null<ObjCMethodDecl>(D)) { + IdentifierInfo *II = OMD->getSelector().getIdentifierInfoForSlot(0); + if (OMD->getMethodFamily() == OMF_dealloc || + OMD->getMethodFamily() == OMF_initialize || + (OMD->getSelector().isUnarySelector() && II->isStr(".cxx_destruct"))) { + markAsIgnoreThreadCheckingAtRuntime(Fn); + } + } + } + + // Ignore unrelated casts in STL allocate() since the allocator must cast + // from void* to T* before object initialization completes. Don't match on the + // namespace because not all allocators are in std:: + if (D && SanOpts.has(SanitizerKind::CFIUnrelatedCast)) { + if (matchesStlAllocatorFn(D, getContext())) + SanOpts.Mask &= ~SanitizerKind::CFIUnrelatedCast; + } + + // Ignore null checks in coroutine functions since the coroutines passes + // are not aware of how to move the extra UBSan instructions across the split + // coroutine boundaries. + if (D && SanOpts.has(SanitizerKind::Null)) + if (const auto *FD = dyn_cast<FunctionDecl>(D)) + if (FD->getBody() && + FD->getBody()->getStmtClass() == Stmt::CoroutineBodyStmtClass) + SanOpts.Mask &= ~SanitizerKind::Null; + + if (D) { + // Apply xray attributes to the function (as a string, for now) + if (const auto *XRayAttr = D->getAttr<XRayInstrumentAttr>()) { + if (CGM.getCodeGenOpts().XRayInstrumentationBundle.has( + XRayInstrKind::Function)) { + if (XRayAttr->alwaysXRayInstrument() && ShouldXRayInstrumentFunction()) + Fn->addFnAttr("function-instrument", "xray-always"); + if (XRayAttr->neverXRayInstrument()) + Fn->addFnAttr("function-instrument", "xray-never"); + if (const auto *LogArgs = D->getAttr<XRayLogArgsAttr>()) + if (ShouldXRayInstrumentFunction()) + Fn->addFnAttr("xray-log-args", + llvm::utostr(LogArgs->getArgumentCount())); + } + } else { + if (ShouldXRayInstrumentFunction() && !CGM.imbueXRayAttrs(Fn, Loc)) + Fn->addFnAttr( + "xray-instruction-threshold", + llvm::itostr(CGM.getCodeGenOpts().XRayInstructionThreshold)); + } + + unsigned Count, Offset; + if (const auto *Attr = D->getAttr<PatchableFunctionEntryAttr>()) { + Count = Attr->getCount(); + Offset = Attr->getOffset(); + } else { + Count = CGM.getCodeGenOpts().PatchableFunctionEntryCount; + Offset = CGM.getCodeGenOpts().PatchableFunctionEntryOffset; + } + if (Count && Offset <= Count) { + Fn->addFnAttr("patchable-function-entry", std::to_string(Count - Offset)); + if (Offset) + Fn->addFnAttr("patchable-function-prefix", std::to_string(Offset)); + } + } + + // Add no-jump-tables value. + Fn->addFnAttr("no-jump-tables", + llvm::toStringRef(CGM.getCodeGenOpts().NoUseJumpTables)); + + // Add no-inline-line-tables value. + if (CGM.getCodeGenOpts().NoInlineLineTables) + Fn->addFnAttr("no-inline-line-tables"); + + // Add profile-sample-accurate value. + if (CGM.getCodeGenOpts().ProfileSampleAccurate) + Fn->addFnAttr("profile-sample-accurate"); + + if (D && D->hasAttr<CFICanonicalJumpTableAttr>()) + Fn->addFnAttr("cfi-canonical-jump-table"); + + if (getLangOpts().OpenCL) { + // Add metadata for a kernel function. + if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) + EmitOpenCLKernelMetadata(FD, Fn); + } + + // If we are checking function types, emit a function type signature as + // prologue data. + if (getLangOpts().CPlusPlus && SanOpts.has(SanitizerKind::Function)) { + if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) { + if (llvm::Constant *PrologueSig = getPrologueSignature(CGM, FD)) { + // Remove any (C++17) exception specifications, to allow calling e.g. a + // noexcept function through a non-noexcept pointer. + auto ProtoTy = + getContext().getFunctionTypeWithExceptionSpec(FD->getType(), + EST_None); + llvm::Constant *FTRTTIConst = + CGM.GetAddrOfRTTIDescriptor(ProtoTy, /*ForEH=*/true); + llvm::Constant *FTRTTIConstEncoded = + EncodeAddrForUseInPrologue(Fn, FTRTTIConst); + llvm::Constant *PrologueStructElems[] = {PrologueSig, + FTRTTIConstEncoded}; + llvm::Constant *PrologueStructConst = + llvm::ConstantStruct::getAnon(PrologueStructElems, /*Packed=*/true); + Fn->setPrologueData(PrologueStructConst); + } + } + } + + // If we're checking nullability, we need to know whether we can check the + // return value. Initialize the flag to 'true' and refine it in EmitParmDecl. + if (SanOpts.has(SanitizerKind::NullabilityReturn)) { + auto Nullability = FnRetTy->getNullability(getContext()); + if (Nullability && *Nullability == NullabilityKind::NonNull) { + if (!(SanOpts.has(SanitizerKind::ReturnsNonnullAttribute) && + CurCodeDecl && CurCodeDecl->getAttr<ReturnsNonNullAttr>())) + RetValNullabilityPrecondition = + llvm::ConstantInt::getTrue(getLLVMContext()); + } + } + + // If we're in C++ mode and the function name is "main", it is guaranteed + // to be norecurse by the standard (3.6.1.3 "The function main shall not be + // used within a program"). + if (getLangOpts().CPlusPlus) + if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) + if (FD->isMain()) + Fn->addFnAttr(llvm::Attribute::NoRecurse); + + if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) + if (FD->usesFPIntrin()) + Fn->addFnAttr(llvm::Attribute::StrictFP); + + // If a custom alignment is used, force realigning to this alignment on + // any main function which certainly will need it. + if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) + if ((FD->isMain() || FD->isMSVCRTEntryPoint()) && + CGM.getCodeGenOpts().StackAlignment) + Fn->addFnAttr("stackrealign"); + + llvm::BasicBlock *EntryBB = createBasicBlock("entry", CurFn); + + // Create a marker to make it easy to insert allocas into the entryblock + // later. Don't create this with the builder, because we don't want it + // folded. + llvm::Value *Undef = llvm::UndefValue::get(Int32Ty); + AllocaInsertPt = new llvm::BitCastInst(Undef, Int32Ty, "allocapt", EntryBB); + + ReturnBlock = getJumpDestInCurrentScope("return"); + + Builder.SetInsertPoint(EntryBB); + + // If we're checking the return value, allocate space for a pointer to a + // precise source location of the checked return statement. + if (requiresReturnValueCheck()) { + ReturnLocation = CreateDefaultAlignTempAlloca(Int8PtrTy, "return.sloc.ptr"); + InitTempAlloca(ReturnLocation, llvm::ConstantPointerNull::get(Int8PtrTy)); + } + + // Emit subprogram debug descriptor. + if (CGDebugInfo *DI = getDebugInfo()) { + // Reconstruct the type from the argument list so that implicit parameters, + // such as 'this' and 'vtt', show up in the debug info. Preserve the calling + // convention. + CallingConv CC = CallingConv::CC_C; + if (auto *FD = dyn_cast_or_null<FunctionDecl>(D)) + if (const auto *SrcFnTy = FD->getType()->getAs<FunctionType>()) + CC = SrcFnTy->getCallConv(); + SmallVector<QualType, 16> ArgTypes; + for (const VarDecl *VD : Args) + ArgTypes.push_back(VD->getType()); + QualType FnType = getContext().getFunctionType( + RetTy, ArgTypes, FunctionProtoType::ExtProtoInfo(CC)); + DI->EmitFunctionStart(GD, Loc, StartLoc, FnType, CurFn, CurFuncIsThunk, + Builder); + } + + if (ShouldInstrumentFunction()) { + if (CGM.getCodeGenOpts().InstrumentFunctions) + CurFn->addFnAttr("instrument-function-entry", "__cyg_profile_func_enter"); + if (CGM.getCodeGenOpts().InstrumentFunctionsAfterInlining) + CurFn->addFnAttr("instrument-function-entry-inlined", + "__cyg_profile_func_enter"); + if (CGM.getCodeGenOpts().InstrumentFunctionEntryBare) + CurFn->addFnAttr("instrument-function-entry-inlined", + "__cyg_profile_func_enter_bare"); + } + + // Since emitting the mcount call here impacts optimizations such as function + // inlining, we just add an attribute to insert a mcount call in backend. + // The attribute "counting-function" is set to mcount function name which is + // architecture dependent. + if (CGM.getCodeGenOpts().InstrumentForProfiling) { + // Calls to fentry/mcount should not be generated if function has + // the no_instrument_function attribute. + if (!CurFuncDecl || !CurFuncDecl->hasAttr<NoInstrumentFunctionAttr>()) { + if (CGM.getCodeGenOpts().CallFEntry) + Fn->addFnAttr("fentry-call", "true"); + else { + Fn->addFnAttr("instrument-function-entry-inlined", + getTarget().getMCountName()); + } + if (CGM.getCodeGenOpts().MNopMCount) { + if (!CGM.getCodeGenOpts().CallFEntry) + CGM.getDiags().Report(diag::err_opt_not_valid_without_opt) + << "-mnop-mcount" << "-mfentry"; + Fn->addFnAttr("mnop-mcount"); + } + + if (CGM.getCodeGenOpts().RecordMCount) { + if (!CGM.getCodeGenOpts().CallFEntry) + CGM.getDiags().Report(diag::err_opt_not_valid_without_opt) + << "-mrecord-mcount" << "-mfentry"; + Fn->addFnAttr("mrecord-mcount"); + } + } + } + + if (CGM.getCodeGenOpts().PackedStack) { + if (getContext().getTargetInfo().getTriple().getArch() != + llvm::Triple::systemz) + CGM.getDiags().Report(diag::err_opt_not_valid_on_target) + << "-mpacked-stack"; + Fn->addFnAttr("packed-stack"); + } + + if (RetTy->isVoidType()) { + // Void type; nothing to return. + ReturnValue = Address::invalid(); + + // Count the implicit return. + if (!endsWithReturn(D)) + ++NumReturnExprs; + } else if (CurFnInfo->getReturnInfo().getKind() == ABIArgInfo::Indirect) { + // Indirect return; emit returned value directly into sret slot. + // This reduces code size, and affects correctness in C++. + auto AI = CurFn->arg_begin(); + if (CurFnInfo->getReturnInfo().isSRetAfterThis()) + ++AI; + ReturnValue = Address(&*AI, CurFnInfo->getReturnInfo().getIndirectAlign()); + if (!CurFnInfo->getReturnInfo().getIndirectByVal()) { + ReturnValuePointer = + CreateDefaultAlignTempAlloca(Int8PtrTy, "result.ptr"); + Builder.CreateStore(Builder.CreatePointerBitCastOrAddrSpaceCast( + ReturnValue.getPointer(), Int8PtrTy), + ReturnValuePointer); + } + } else if (CurFnInfo->getReturnInfo().getKind() == ABIArgInfo::InAlloca && + !hasScalarEvaluationKind(CurFnInfo->getReturnType())) { + // Load the sret pointer from the argument struct and return into that. + unsigned Idx = CurFnInfo->getReturnInfo().getInAllocaFieldIndex(); + llvm::Function::arg_iterator EI = CurFn->arg_end(); + --EI; + llvm::Value *Addr = Builder.CreateStructGEP(nullptr, &*EI, Idx); + ReturnValuePointer = Address(Addr, getPointerAlign()); + Addr = Builder.CreateAlignedLoad(Addr, getPointerAlign(), "agg.result"); + ReturnValue = Address(Addr, getNaturalTypeAlignment(RetTy)); + } else { + ReturnValue = CreateIRTemp(RetTy, "retval"); + + // Tell the epilog emitter to autorelease the result. We do this + // now so that various specialized functions can suppress it + // during their IR-generation. + if (getLangOpts().ObjCAutoRefCount && + !CurFnInfo->isReturnsRetained() && + RetTy->isObjCRetainableType()) + AutoreleaseResult = true; + } + + EmitStartEHSpec(CurCodeDecl); + + PrologueCleanupDepth = EHStack.stable_begin(); + + // Emit OpenMP specific initialization of the device functions. + if (getLangOpts().OpenMP && CurCodeDecl) + CGM.getOpenMPRuntime().emitFunctionProlog(*this, CurCodeDecl); + + EmitFunctionProlog(*CurFnInfo, CurFn, Args); + + if (D && isa<CXXMethodDecl>(D) && cast<CXXMethodDecl>(D)->isInstance()) { + CGM.getCXXABI().EmitInstanceFunctionProlog(*this); + const CXXMethodDecl *MD = cast<CXXMethodDecl>(D); + if (MD->getParent()->isLambda() && + MD->getOverloadedOperator() == OO_Call) { + // We're in a lambda; figure out the captures. + MD->getParent()->getCaptureFields(LambdaCaptureFields, + LambdaThisCaptureField); + if (LambdaThisCaptureField) { + // If the lambda captures the object referred to by '*this' - either by + // value or by reference, make sure CXXThisValue points to the correct + // object. + + // Get the lvalue for the field (which is a copy of the enclosing object + // or contains the address of the enclosing object). + LValue ThisFieldLValue = EmitLValueForLambdaField(LambdaThisCaptureField); + if (!LambdaThisCaptureField->getType()->isPointerType()) { + // If the enclosing object was captured by value, just use its address. + CXXThisValue = ThisFieldLValue.getAddress(*this).getPointer(); + } else { + // Load the lvalue pointed to by the field, since '*this' was captured + // by reference. + CXXThisValue = + EmitLoadOfLValue(ThisFieldLValue, SourceLocation()).getScalarVal(); + } + } + for (auto *FD : MD->getParent()->fields()) { + if (FD->hasCapturedVLAType()) { + auto *ExprArg = EmitLoadOfLValue(EmitLValueForLambdaField(FD), + SourceLocation()).getScalarVal(); + auto VAT = FD->getCapturedVLAType(); + VLASizeMap[VAT->getSizeExpr()] = ExprArg; + } + } + } else { + // Not in a lambda; just use 'this' from the method. + // FIXME: Should we generate a new load for each use of 'this'? The + // fast register allocator would be happier... + CXXThisValue = CXXABIThisValue; + } + + // Check the 'this' pointer once per function, if it's available. + if (CXXABIThisValue) { + SanitizerSet SkippedChecks; + SkippedChecks.set(SanitizerKind::ObjectSize, true); + QualType ThisTy = MD->getThisType(); + + // If this is the call operator of a lambda with no capture-default, it + // may have a static invoker function, which may call this operator with + // a null 'this' pointer. + if (isLambdaCallOperator(MD) && + MD->getParent()->getLambdaCaptureDefault() == LCD_None) + SkippedChecks.set(SanitizerKind::Null, true); + + EmitTypeCheck(isa<CXXConstructorDecl>(MD) ? TCK_ConstructorCall + : TCK_MemberCall, + Loc, CXXABIThisValue, ThisTy, + getContext().getTypeAlignInChars(ThisTy->getPointeeType()), + SkippedChecks); + } + } + + // If any of the arguments have a variably modified type, make sure to + // emit the type size. + for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end(); + i != e; ++i) { + const VarDecl *VD = *i; + + // Dig out the type as written from ParmVarDecls; it's unclear whether + // the standard (C99 6.9.1p10) requires this, but we're following the + // precedent set by gcc. + QualType Ty; + if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(VD)) + Ty = PVD->getOriginalType(); + else + Ty = VD->getType(); + + if (Ty->isVariablyModifiedType()) + EmitVariablyModifiedType(Ty); + } + // Emit a location at the end of the prologue. + if (CGDebugInfo *DI = getDebugInfo()) + DI->EmitLocation(Builder, StartLoc); + + // TODO: Do we need to handle this in two places like we do with + // target-features/target-cpu? + if (CurFuncDecl) + if (const auto *VecWidth = CurFuncDecl->getAttr<MinVectorWidthAttr>()) + LargestVectorWidth = VecWidth->getVectorWidth(); +} + +void CodeGenFunction::EmitFunctionBody(const Stmt *Body) { + incrementProfileCounter(Body); + if (const CompoundStmt *S = dyn_cast<CompoundStmt>(Body)) + EmitCompoundStmtWithoutScope(*S); + else + EmitStmt(Body); +} + +/// When instrumenting to collect profile data, the counts for some blocks +/// such as switch cases need to not include the fall-through counts, so +/// emit a branch around the instrumentation code. When not instrumenting, +/// this just calls EmitBlock(). +void CodeGenFunction::EmitBlockWithFallThrough(llvm::BasicBlock *BB, + const Stmt *S) { + llvm::BasicBlock *SkipCountBB = nullptr; + if (HaveInsertPoint() && CGM.getCodeGenOpts().hasProfileClangInstr()) { + // When instrumenting for profiling, the fallthrough to certain + // statements needs to skip over the instrumentation code so that we + // get an accurate count. + SkipCountBB = createBasicBlock("skipcount"); + EmitBranch(SkipCountBB); + } + EmitBlock(BB); + uint64_t CurrentCount = getCurrentProfileCount(); + incrementProfileCounter(S); + setCurrentProfileCount(getCurrentProfileCount() + CurrentCount); + if (SkipCountBB) + EmitBlock(SkipCountBB); +} + +/// Tries to mark the given function nounwind based on the +/// non-existence of any throwing calls within it. We believe this is +/// lightweight enough to do at -O0. +static void TryMarkNoThrow(llvm::Function *F) { + // LLVM treats 'nounwind' on a function as part of the type, so we + // can't do this on functions that can be overwritten. + if (F->isInterposable()) return; + + for (llvm::BasicBlock &BB : *F) + for (llvm::Instruction &I : BB) + if (I.mayThrow()) + return; + + F->setDoesNotThrow(); +} + +QualType CodeGenFunction::BuildFunctionArgList(GlobalDecl GD, + FunctionArgList &Args) { + const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl()); + QualType ResTy = FD->getReturnType(); + + const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD); + if (MD && MD->isInstance()) { + if (CGM.getCXXABI().HasThisReturn(GD)) + ResTy = MD->getThisType(); + else if (CGM.getCXXABI().hasMostDerivedReturn(GD)) + ResTy = CGM.getContext().VoidPtrTy; + CGM.getCXXABI().buildThisParam(*this, Args); + } + + // The base version of an inheriting constructor whose constructed base is a + // virtual base is not passed any arguments (because it doesn't actually call + // the inherited constructor). + bool PassedParams = true; + if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) + if (auto Inherited = CD->getInheritedConstructor()) + PassedParams = + getTypes().inheritingCtorHasParams(Inherited, GD.getCtorType()); + + if (PassedParams) { + for (auto *Param : FD->parameters()) { + Args.push_back(Param); + if (!Param->hasAttr<PassObjectSizeAttr>()) + continue; + + auto *Implicit = ImplicitParamDecl::Create( + getContext(), Param->getDeclContext(), Param->getLocation(), + /*Id=*/nullptr, getContext().getSizeType(), ImplicitParamDecl::Other); + SizeArguments[Param] = Implicit; + Args.push_back(Implicit); + } + } + + if (MD && (isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD))) + CGM.getCXXABI().addImplicitStructorParams(*this, ResTy, Args); + + return ResTy; +} + +static bool +shouldUseUndefinedBehaviorReturnOptimization(const FunctionDecl *FD, + const ASTContext &Context) { + QualType T = FD->getReturnType(); + // Avoid the optimization for functions that return a record type with a + // trivial destructor or another trivially copyable type. + if (const RecordType *RT = T.getCanonicalType()->getAs<RecordType>()) { + if (const auto *ClassDecl = dyn_cast<CXXRecordDecl>(RT->getDecl())) + return !ClassDecl->hasTrivialDestructor(); + } + return !T.isTriviallyCopyableType(Context); +} + +void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn, + const CGFunctionInfo &FnInfo) { + const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl()); + CurGD = GD; + + FunctionArgList Args; + QualType ResTy = BuildFunctionArgList(GD, Args); + + // Check if we should generate debug info for this function. + if (FD->hasAttr<NoDebugAttr>()) + DebugInfo = nullptr; // disable debug info indefinitely for this function + + // The function might not have a body if we're generating thunks for a + // function declaration. + SourceRange BodyRange; + if (Stmt *Body = FD->getBody()) + BodyRange = Body->getSourceRange(); + else + BodyRange = FD->getLocation(); + CurEHLocation = BodyRange.getEnd(); + + // Use the location of the start of the function to determine where + // the function definition is located. By default use the location + // of the declaration as the location for the subprogram. A function + // may lack a declaration in the source code if it is created by code + // gen. (examples: _GLOBAL__I_a, __cxx_global_array_dtor, thunk). + SourceLocation Loc = FD->getLocation(); + + // If this is a function specialization then use the pattern body + // as the location for the function. + if (const FunctionDecl *SpecDecl = FD->getTemplateInstantiationPattern()) + if (SpecDecl->hasBody(SpecDecl)) + Loc = SpecDecl->getLocation(); + + Stmt *Body = FD->getBody(); + + // Initialize helper which will detect jumps which can cause invalid lifetime + // markers. + if (Body && ShouldEmitLifetimeMarkers) + Bypasses.Init(Body); + + // Emit the standard function prologue. + StartFunction(GD, ResTy, Fn, FnInfo, Args, Loc, BodyRange.getBegin()); + + // Generate the body of the function. + PGO.assignRegionCounters(GD, CurFn); + if (isa<CXXDestructorDecl>(FD)) + EmitDestructorBody(Args); + else if (isa<CXXConstructorDecl>(FD)) + EmitConstructorBody(Args); + else if (getLangOpts().CUDA && + !getLangOpts().CUDAIsDevice && + FD->hasAttr<CUDAGlobalAttr>()) + CGM.getCUDARuntime().emitDeviceStub(*this, Args); + else if (isa<CXXMethodDecl>(FD) && + cast<CXXMethodDecl>(FD)->isLambdaStaticInvoker()) { + // The lambda static invoker function is special, because it forwards or + // clones the body of the function call operator (but is actually static). + EmitLambdaStaticInvokeBody(cast<CXXMethodDecl>(FD)); + } else if (FD->isDefaulted() && isa<CXXMethodDecl>(FD) && + (cast<CXXMethodDecl>(FD)->isCopyAssignmentOperator() || + cast<CXXMethodDecl>(FD)->isMoveAssignmentOperator())) { + // Implicit copy-assignment gets the same special treatment as implicit + // copy-constructors. + emitImplicitAssignmentOperatorBody(Args); + } else if (Body) { + EmitFunctionBody(Body); + } else + llvm_unreachable("no definition for emitted function"); + + // C++11 [stmt.return]p2: + // Flowing off the end of a function [...] results in undefined behavior in + // a value-returning function. + // C11 6.9.1p12: + // If the '}' that terminates a function is reached, and the value of the + // function call is used by the caller, the behavior is undefined. + if (getLangOpts().CPlusPlus && !FD->hasImplicitReturnZero() && !SawAsmBlock && + !FD->getReturnType()->isVoidType() && Builder.GetInsertBlock()) { + bool ShouldEmitUnreachable = + CGM.getCodeGenOpts().StrictReturn || + shouldUseUndefinedBehaviorReturnOptimization(FD, getContext()); + if (SanOpts.has(SanitizerKind::Return)) { + SanitizerScope SanScope(this); + llvm::Value *IsFalse = Builder.getFalse(); + EmitCheck(std::make_pair(IsFalse, SanitizerKind::Return), + SanitizerHandler::MissingReturn, + EmitCheckSourceLocation(FD->getLocation()), None); + } else if (ShouldEmitUnreachable) { + if (CGM.getCodeGenOpts().OptimizationLevel == 0) + EmitTrapCall(llvm::Intrinsic::trap); + } + if (SanOpts.has(SanitizerKind::Return) || ShouldEmitUnreachable) { + Builder.CreateUnreachable(); + Builder.ClearInsertionPoint(); + } + } + + // Emit the standard function epilogue. + FinishFunction(BodyRange.getEnd()); + + // If we haven't marked the function nothrow through other means, do + // a quick pass now to see if we can. + if (!CurFn->doesNotThrow()) + TryMarkNoThrow(CurFn); +} + +/// ContainsLabel - Return true if the statement contains a label in it. If +/// this statement is not executed normally, it not containing a label means +/// that we can just remove the code. +bool CodeGenFunction::ContainsLabel(const Stmt *S, bool IgnoreCaseStmts) { + // Null statement, not a label! + if (!S) return false; + + // If this is a label, we have to emit the code, consider something like: + // if (0) { ... foo: bar(); } goto foo; + // + // TODO: If anyone cared, we could track __label__'s, since we know that you + // can't jump to one from outside their declared region. + if (isa<LabelStmt>(S)) + return true; + + // If this is a case/default statement, and we haven't seen a switch, we have + // to emit the code. + if (isa<SwitchCase>(S) && !IgnoreCaseStmts) + return true; + + // If this is a switch statement, we want to ignore cases below it. + if (isa<SwitchStmt>(S)) + IgnoreCaseStmts = true; + + // Scan subexpressions for verboten labels. + for (const Stmt *SubStmt : S->children()) + if (ContainsLabel(SubStmt, IgnoreCaseStmts)) + return true; + + return false; +} + +/// containsBreak - Return true if the statement contains a break out of it. +/// If the statement (recursively) contains a switch or loop with a break +/// inside of it, this is fine. +bool CodeGenFunction::containsBreak(const Stmt *S) { + // Null statement, not a label! + if (!S) return false; + + // If this is a switch or loop that defines its own break scope, then we can + // include it and anything inside of it. + if (isa<SwitchStmt>(S) || isa<WhileStmt>(S) || isa<DoStmt>(S) || + isa<ForStmt>(S)) + return false; + + if (isa<BreakStmt>(S)) + return true; + + // Scan subexpressions for verboten breaks. + for (const Stmt *SubStmt : S->children()) + if (containsBreak(SubStmt)) + return true; + + return false; +} + +bool CodeGenFunction::mightAddDeclToScope(const Stmt *S) { + if (!S) return false; + + // Some statement kinds add a scope and thus never add a decl to the current + // scope. Note, this list is longer than the list of statements that might + // have an unscoped decl nested within them, but this way is conservatively + // correct even if more statement kinds are added. + if (isa<IfStmt>(S) || isa<SwitchStmt>(S) || isa<WhileStmt>(S) || + isa<DoStmt>(S) || isa<ForStmt>(S) || isa<CompoundStmt>(S) || + isa<CXXForRangeStmt>(S) || isa<CXXTryStmt>(S) || + isa<ObjCForCollectionStmt>(S) || isa<ObjCAtTryStmt>(S)) + return false; + + if (isa<DeclStmt>(S)) + return true; + + for (const Stmt *SubStmt : S->children()) + if (mightAddDeclToScope(SubStmt)) + return true; + + return false; +} + +/// ConstantFoldsToSimpleInteger - If the specified expression does not fold +/// to a constant, or if it does but contains a label, return false. If it +/// constant folds return true and set the boolean result in Result. +bool CodeGenFunction::ConstantFoldsToSimpleInteger(const Expr *Cond, + bool &ResultBool, + bool AllowLabels) { + llvm::APSInt ResultInt; + if (!ConstantFoldsToSimpleInteger(Cond, ResultInt, AllowLabels)) + return false; + + ResultBool = ResultInt.getBoolValue(); + return true; +} + +/// ConstantFoldsToSimpleInteger - If the specified expression does not fold +/// to a constant, or if it does but contains a label, return false. If it +/// constant folds return true and set the folded value. +bool CodeGenFunction::ConstantFoldsToSimpleInteger(const Expr *Cond, + llvm::APSInt &ResultInt, + bool AllowLabels) { + // FIXME: Rename and handle conversion of other evaluatable things + // to bool. + Expr::EvalResult Result; + if (!Cond->EvaluateAsInt(Result, getContext())) + return false; // Not foldable, not integer or not fully evaluatable. + + llvm::APSInt Int = Result.Val.getInt(); + if (!AllowLabels && CodeGenFunction::ContainsLabel(Cond)) + return false; // Contains a label. + + ResultInt = Int; + return true; +} + + + +/// EmitBranchOnBoolExpr - Emit a branch on a boolean condition (e.g. for an if +/// statement) to the specified blocks. Based on the condition, this might try +/// to simplify the codegen of the conditional based on the branch. +/// +void CodeGenFunction::EmitBranchOnBoolExpr(const Expr *Cond, + llvm::BasicBlock *TrueBlock, + llvm::BasicBlock *FalseBlock, + uint64_t TrueCount) { + Cond = Cond->IgnoreParens(); + + if (const BinaryOperator *CondBOp = dyn_cast<BinaryOperator>(Cond)) { + + // Handle X && Y in a condition. + if (CondBOp->getOpcode() == BO_LAnd) { + // If we have "1 && X", simplify the code. "0 && X" would have constant + // folded if the case was simple enough. + bool ConstantBool = false; + if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) && + ConstantBool) { + // br(1 && X) -> br(X). + incrementProfileCounter(CondBOp); + return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock, + TrueCount); + } + + // If we have "X && 1", simplify the code to use an uncond branch. + // "X && 0" would have been constant folded to 0. + if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) && + ConstantBool) { + // br(X && 1) -> br(X). + return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock, + TrueCount); + } + + // Emit the LHS as a conditional. If the LHS conditional is false, we + // want to jump to the FalseBlock. + llvm::BasicBlock *LHSTrue = createBasicBlock("land.lhs.true"); + // The counter tells us how often we evaluate RHS, and all of TrueCount + // can be propagated to that branch. + uint64_t RHSCount = getProfileCount(CondBOp->getRHS()); + + ConditionalEvaluation eval(*this); + { + ApplyDebugLocation DL(*this, Cond); + EmitBranchOnBoolExpr(CondBOp->getLHS(), LHSTrue, FalseBlock, RHSCount); + EmitBlock(LHSTrue); + } + + incrementProfileCounter(CondBOp); + setCurrentProfileCount(getProfileCount(CondBOp->getRHS())); + + // Any temporaries created here are conditional. + eval.begin(*this); + EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock, TrueCount); + eval.end(*this); + + return; + } + + if (CondBOp->getOpcode() == BO_LOr) { + // If we have "0 || X", simplify the code. "1 || X" would have constant + // folded if the case was simple enough. + bool ConstantBool = false; + if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) && + !ConstantBool) { + // br(0 || X) -> br(X). + incrementProfileCounter(CondBOp); + return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock, + TrueCount); + } + + // If we have "X || 0", simplify the code to use an uncond branch. + // "X || 1" would have been constant folded to 1. + if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) && + !ConstantBool) { + // br(X || 0) -> br(X). + return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock, + TrueCount); + } + + // Emit the LHS as a conditional. If the LHS conditional is true, we + // want to jump to the TrueBlock. + llvm::BasicBlock *LHSFalse = createBasicBlock("lor.lhs.false"); + // We have the count for entry to the RHS and for the whole expression + // being true, so we can divy up True count between the short circuit and + // the RHS. + uint64_t LHSCount = + getCurrentProfileCount() - getProfileCount(CondBOp->getRHS()); + uint64_t RHSCount = TrueCount - LHSCount; + + ConditionalEvaluation eval(*this); + { + ApplyDebugLocation DL(*this, Cond); + EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, LHSFalse, LHSCount); + EmitBlock(LHSFalse); + } + + incrementProfileCounter(CondBOp); + setCurrentProfileCount(getProfileCount(CondBOp->getRHS())); + + // Any temporaries created here are conditional. + eval.begin(*this); + EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock, RHSCount); + + eval.end(*this); + + return; + } + } + + if (const UnaryOperator *CondUOp = dyn_cast<UnaryOperator>(Cond)) { + // br(!x, t, f) -> br(x, f, t) + if (CondUOp->getOpcode() == UO_LNot) { + // Negate the count. + uint64_t FalseCount = getCurrentProfileCount() - TrueCount; + // Negate the condition and swap the destination blocks. + return EmitBranchOnBoolExpr(CondUOp->getSubExpr(), FalseBlock, TrueBlock, + FalseCount); + } + } + + if (const ConditionalOperator *CondOp = dyn_cast<ConditionalOperator>(Cond)) { + // br(c ? x : y, t, f) -> br(c, br(x, t, f), br(y, t, f)) + llvm::BasicBlock *LHSBlock = createBasicBlock("cond.true"); + llvm::BasicBlock *RHSBlock = createBasicBlock("cond.false"); + + ConditionalEvaluation cond(*this); + EmitBranchOnBoolExpr(CondOp->getCond(), LHSBlock, RHSBlock, + getProfileCount(CondOp)); + + // When computing PGO branch weights, we only know the overall count for + // the true block. This code is essentially doing tail duplication of the + // naive code-gen, introducing new edges for which counts are not + // available. Divide the counts proportionally between the LHS and RHS of + // the conditional operator. + uint64_t LHSScaledTrueCount = 0; + if (TrueCount) { + double LHSRatio = + getProfileCount(CondOp) / (double)getCurrentProfileCount(); + LHSScaledTrueCount = TrueCount * LHSRatio; + } + + cond.begin(*this); + EmitBlock(LHSBlock); + incrementProfileCounter(CondOp); + { + ApplyDebugLocation DL(*this, Cond); + EmitBranchOnBoolExpr(CondOp->getLHS(), TrueBlock, FalseBlock, + LHSScaledTrueCount); + } + cond.end(*this); + + cond.begin(*this); + EmitBlock(RHSBlock); + EmitBranchOnBoolExpr(CondOp->getRHS(), TrueBlock, FalseBlock, + TrueCount - LHSScaledTrueCount); + cond.end(*this); + + return; + } + + if (const CXXThrowExpr *Throw = dyn_cast<CXXThrowExpr>(Cond)) { + // Conditional operator handling can give us a throw expression as a + // condition for a case like: + // br(c ? throw x : y, t, f) -> br(c, br(throw x, t, f), br(y, t, f) + // Fold this to: + // br(c, throw x, br(y, t, f)) + EmitCXXThrowExpr(Throw, /*KeepInsertionPoint*/false); + return; + } + + // If the branch has a condition wrapped by __builtin_unpredictable, + // create metadata that specifies that the branch is unpredictable. + // Don't bother if not optimizing because that metadata would not be used. + llvm::MDNode *Unpredictable = nullptr; + auto *Call = dyn_cast<CallExpr>(Cond->IgnoreImpCasts()); + if (Call && CGM.getCodeGenOpts().OptimizationLevel != 0) { + auto *FD = dyn_cast_or_null<FunctionDecl>(Call->getCalleeDecl()); + if (FD && FD->getBuiltinID() == Builtin::BI__builtin_unpredictable) { + llvm::MDBuilder MDHelper(getLLVMContext()); + Unpredictable = MDHelper.createUnpredictable(); + } + } + + // Create branch weights based on the number of times we get here and the + // number of times the condition should be true. + uint64_t CurrentCount = std::max(getCurrentProfileCount(), TrueCount); + llvm::MDNode *Weights = + createProfileWeights(TrueCount, CurrentCount - TrueCount); + + // Emit the code with the fully general case. + llvm::Value *CondV; + { + ApplyDebugLocation DL(*this, Cond); + CondV = EvaluateExprAsBool(Cond); + } + Builder.CreateCondBr(CondV, TrueBlock, FalseBlock, Weights, Unpredictable); +} + +/// ErrorUnsupported - Print out an error that codegen doesn't support the +/// specified stmt yet. +void CodeGenFunction::ErrorUnsupported(const Stmt *S, const char *Type) { + CGM.ErrorUnsupported(S, Type); +} + +/// emitNonZeroVLAInit - Emit the "zero" initialization of a +/// variable-length array whose elements have a non-zero bit-pattern. +/// +/// \param baseType the inner-most element type of the array +/// \param src - a char* pointing to the bit-pattern for a single +/// base element of the array +/// \param sizeInChars - the total size of the VLA, in chars +static void emitNonZeroVLAInit(CodeGenFunction &CGF, QualType baseType, + Address dest, Address src, + llvm::Value *sizeInChars) { + CGBuilderTy &Builder = CGF.Builder; + + CharUnits baseSize = CGF.getContext().getTypeSizeInChars(baseType); + llvm::Value *baseSizeInChars + = llvm::ConstantInt::get(CGF.IntPtrTy, baseSize.getQuantity()); + + Address begin = + Builder.CreateElementBitCast(dest, CGF.Int8Ty, "vla.begin"); + llvm::Value *end = + Builder.CreateInBoundsGEP(begin.getPointer(), sizeInChars, "vla.end"); + + llvm::BasicBlock *originBB = CGF.Builder.GetInsertBlock(); + llvm::BasicBlock *loopBB = CGF.createBasicBlock("vla-init.loop"); + llvm::BasicBlock *contBB = CGF.createBasicBlock("vla-init.cont"); + + // Make a loop over the VLA. C99 guarantees that the VLA element + // count must be nonzero. + CGF.EmitBlock(loopBB); + + llvm::PHINode *cur = Builder.CreatePHI(begin.getType(), 2, "vla.cur"); + cur->addIncoming(begin.getPointer(), originBB); + + CharUnits curAlign = + dest.getAlignment().alignmentOfArrayElement(baseSize); + + // memcpy the individual element bit-pattern. + Builder.CreateMemCpy(Address(cur, curAlign), src, baseSizeInChars, + /*volatile*/ false); + + // Go to the next element. + llvm::Value *next = + Builder.CreateInBoundsGEP(CGF.Int8Ty, cur, baseSizeInChars, "vla.next"); + + // Leave if that's the end of the VLA. + llvm::Value *done = Builder.CreateICmpEQ(next, end, "vla-init.isdone"); + Builder.CreateCondBr(done, contBB, loopBB); + cur->addIncoming(next, loopBB); + + CGF.EmitBlock(contBB); +} + +void +CodeGenFunction::EmitNullInitialization(Address DestPtr, QualType Ty) { + // Ignore empty classes in C++. + if (getLangOpts().CPlusPlus) { + if (const RecordType *RT = Ty->getAs<RecordType>()) { + if (cast<CXXRecordDecl>(RT->getDecl())->isEmpty()) + return; + } + } + + // Cast the dest ptr to the appropriate i8 pointer type. + if (DestPtr.getElementType() != Int8Ty) + DestPtr = Builder.CreateElementBitCast(DestPtr, Int8Ty); + + // Get size and alignment info for this aggregate. + CharUnits size = getContext().getTypeSizeInChars(Ty); + + llvm::Value *SizeVal; + const VariableArrayType *vla; + + // Don't bother emitting a zero-byte memset. + if (size.isZero()) { + // But note that getTypeInfo returns 0 for a VLA. + if (const VariableArrayType *vlaType = + dyn_cast_or_null<VariableArrayType>( + getContext().getAsArrayType(Ty))) { + auto VlaSize = getVLASize(vlaType); + SizeVal = VlaSize.NumElts; + CharUnits eltSize = getContext().getTypeSizeInChars(VlaSize.Type); + if (!eltSize.isOne()) + SizeVal = Builder.CreateNUWMul(SizeVal, CGM.getSize(eltSize)); + vla = vlaType; + } else { + return; + } + } else { + SizeVal = CGM.getSize(size); + vla = nullptr; + } + + // If the type contains a pointer to data member we can't memset it to zero. + // Instead, create a null constant and copy it to the destination. + // TODO: there are other patterns besides zero that we can usefully memset, + // like -1, which happens to be the pattern used by member-pointers. + if (!CGM.getTypes().isZeroInitializable(Ty)) { + // For a VLA, emit a single element, then splat that over the VLA. + if (vla) Ty = getContext().getBaseElementType(vla); + + llvm::Constant *NullConstant = CGM.EmitNullConstant(Ty); + + llvm::GlobalVariable *NullVariable = + new llvm::GlobalVariable(CGM.getModule(), NullConstant->getType(), + /*isConstant=*/true, + llvm::GlobalVariable::PrivateLinkage, + NullConstant, Twine()); + CharUnits NullAlign = DestPtr.getAlignment(); + NullVariable->setAlignment(NullAlign.getAsAlign()); + Address SrcPtr(Builder.CreateBitCast(NullVariable, Builder.getInt8PtrTy()), + NullAlign); + + if (vla) return emitNonZeroVLAInit(*this, Ty, DestPtr, SrcPtr, SizeVal); + + // Get and call the appropriate llvm.memcpy overload. + Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, false); + return; + } + + // Otherwise, just memset the whole thing to zero. This is legal + // because in LLVM, all default initializers (other than the ones we just + // handled above) are guaranteed to have a bit pattern of all zeros. + Builder.CreateMemSet(DestPtr, Builder.getInt8(0), SizeVal, false); +} + +llvm::BlockAddress *CodeGenFunction::GetAddrOfLabel(const LabelDecl *L) { + // Make sure that there is a block for the indirect goto. + if (!IndirectBranch) + GetIndirectGotoBlock(); + + llvm::BasicBlock *BB = getJumpDestForLabel(L).getBlock(); + + // Make sure the indirect branch includes all of the address-taken blocks. + IndirectBranch->addDestination(BB); + return llvm::BlockAddress::get(CurFn, BB); +} + +llvm::BasicBlock *CodeGenFunction::GetIndirectGotoBlock() { + // If we already made the indirect branch for indirect goto, return its block. + if (IndirectBranch) return IndirectBranch->getParent(); + + CGBuilderTy TmpBuilder(*this, createBasicBlock("indirectgoto")); + + // Create the PHI node that indirect gotos will add entries to. + llvm::Value *DestVal = TmpBuilder.CreatePHI(Int8PtrTy, 0, + "indirect.goto.dest"); + + // Create the indirect branch instruction. + IndirectBranch = TmpBuilder.CreateIndirectBr(DestVal); + return IndirectBranch->getParent(); +} + +/// Computes the length of an array in elements, as well as the base +/// element type and a properly-typed first element pointer. +llvm::Value *CodeGenFunction::emitArrayLength(const ArrayType *origArrayType, + QualType &baseType, + Address &addr) { + const ArrayType *arrayType = origArrayType; + + // If it's a VLA, we have to load the stored size. Note that + // this is the size of the VLA in bytes, not its size in elements. + llvm::Value *numVLAElements = nullptr; + if (isa<VariableArrayType>(arrayType)) { + numVLAElements = getVLASize(cast<VariableArrayType>(arrayType)).NumElts; + + // Walk into all VLAs. This doesn't require changes to addr, + // which has type T* where T is the first non-VLA element type. + do { + QualType elementType = arrayType->getElementType(); + arrayType = getContext().getAsArrayType(elementType); + + // If we only have VLA components, 'addr' requires no adjustment. + if (!arrayType) { + baseType = elementType; + return numVLAElements; + } + } while (isa<VariableArrayType>(arrayType)); + + // We get out here only if we find a constant array type + // inside the VLA. + } + + // We have some number of constant-length arrays, so addr should + // have LLVM type [M x [N x [...]]]*. Build a GEP that walks + // down to the first element of addr. + SmallVector<llvm::Value*, 8> gepIndices; + + // GEP down to the array type. + llvm::ConstantInt *zero = Builder.getInt32(0); + gepIndices.push_back(zero); + + uint64_t countFromCLAs = 1; + QualType eltType; + + llvm::ArrayType *llvmArrayType = + dyn_cast<llvm::ArrayType>(addr.getElementType()); + while (llvmArrayType) { + assert(isa<ConstantArrayType>(arrayType)); + assert(cast<ConstantArrayType>(arrayType)->getSize().getZExtValue() + == llvmArrayType->getNumElements()); + + gepIndices.push_back(zero); + countFromCLAs *= llvmArrayType->getNumElements(); + eltType = arrayType->getElementType(); + + llvmArrayType = + dyn_cast<llvm::ArrayType>(llvmArrayType->getElementType()); + arrayType = getContext().getAsArrayType(arrayType->getElementType()); + assert((!llvmArrayType || arrayType) && + "LLVM and Clang types are out-of-synch"); + } + + if (arrayType) { + // From this point onwards, the Clang array type has been emitted + // as some other type (probably a packed struct). Compute the array + // size, and just emit the 'begin' expression as a bitcast. + while (arrayType) { + countFromCLAs *= + cast<ConstantArrayType>(arrayType)->getSize().getZExtValue(); + eltType = arrayType->getElementType(); + arrayType = getContext().getAsArrayType(eltType); + } + + llvm::Type *baseType = ConvertType(eltType); + addr = Builder.CreateElementBitCast(addr, baseType, "array.begin"); + } else { + // Create the actual GEP. + addr = Address(Builder.CreateInBoundsGEP(addr.getPointer(), + gepIndices, "array.begin"), + addr.getAlignment()); + } + + baseType = eltType; + + llvm::Value *numElements + = llvm::ConstantInt::get(SizeTy, countFromCLAs); + + // If we had any VLA dimensions, factor them in. + if (numVLAElements) + numElements = Builder.CreateNUWMul(numVLAElements, numElements); + + return numElements; +} + +CodeGenFunction::VlaSizePair CodeGenFunction::getVLASize(QualType type) { + const VariableArrayType *vla = getContext().getAsVariableArrayType(type); + assert(vla && "type was not a variable array type!"); + return getVLASize(vla); +} + +CodeGenFunction::VlaSizePair +CodeGenFunction::getVLASize(const VariableArrayType *type) { + // The number of elements so far; always size_t. + llvm::Value *numElements = nullptr; + + QualType elementType; + do { + elementType = type->getElementType(); + llvm::Value *vlaSize = VLASizeMap[type->getSizeExpr()]; + assert(vlaSize && "no size for VLA!"); + assert(vlaSize->getType() == SizeTy); + + if (!numElements) { + numElements = vlaSize; + } else { + // It's undefined behavior if this wraps around, so mark it that way. + // FIXME: Teach -fsanitize=undefined to trap this. + numElements = Builder.CreateNUWMul(numElements, vlaSize); + } + } while ((type = getContext().getAsVariableArrayType(elementType))); + + return { numElements, elementType }; +} + +CodeGenFunction::VlaSizePair +CodeGenFunction::getVLAElements1D(QualType type) { + const VariableArrayType *vla = getContext().getAsVariableArrayType(type); + assert(vla && "type was not a variable array type!"); + return getVLAElements1D(vla); +} + +CodeGenFunction::VlaSizePair +CodeGenFunction::getVLAElements1D(const VariableArrayType *Vla) { + llvm::Value *VlaSize = VLASizeMap[Vla->getSizeExpr()]; + assert(VlaSize && "no size for VLA!"); + assert(VlaSize->getType() == SizeTy); + return { VlaSize, Vla->getElementType() }; +} + +void CodeGenFunction::EmitVariablyModifiedType(QualType type) { + assert(type->isVariablyModifiedType() && + "Must pass variably modified type to EmitVLASizes!"); + + EnsureInsertPoint(); + + // We're going to walk down into the type and look for VLA + // expressions. + do { + assert(type->isVariablyModifiedType()); + + const Type *ty = type.getTypePtr(); + switch (ty->getTypeClass()) { + +#define TYPE(Class, Base) +#define ABSTRACT_TYPE(Class, Base) +#define NON_CANONICAL_TYPE(Class, Base) +#define DEPENDENT_TYPE(Class, Base) case Type::Class: +#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) +#include "clang/AST/TypeNodes.inc" + llvm_unreachable("unexpected dependent type!"); + + // These types are never variably-modified. + case Type::Builtin: + case Type::Complex: + case Type::Vector: + case Type::ExtVector: + case Type::Record: + case Type::Enum: + case Type::Elaborated: + case Type::TemplateSpecialization: + case Type::ObjCTypeParam: + case Type::ObjCObject: + case Type::ObjCInterface: + case Type::ObjCObjectPointer: + llvm_unreachable("type class is never variably-modified!"); + + case Type::Adjusted: + type = cast<AdjustedType>(ty)->getAdjustedType(); + break; + + case Type::Decayed: + type = cast<DecayedType>(ty)->getPointeeType(); + break; + + case Type::Pointer: + type = cast<PointerType>(ty)->getPointeeType(); + break; + + case Type::BlockPointer: + type = cast<BlockPointerType>(ty)->getPointeeType(); + break; + + case Type::LValueReference: + case Type::RValueReference: + type = cast<ReferenceType>(ty)->getPointeeType(); + break; + + case Type::MemberPointer: + type = cast<MemberPointerType>(ty)->getPointeeType(); + break; + + case Type::ConstantArray: + case Type::IncompleteArray: + // Losing element qualification here is fine. + type = cast<ArrayType>(ty)->getElementType(); + break; + + case Type::VariableArray: { + // Losing element qualification here is fine. + const VariableArrayType *vat = cast<VariableArrayType>(ty); + + // Unknown size indication requires no size computation. + // Otherwise, evaluate and record it. + if (const Expr *size = vat->getSizeExpr()) { + // It's possible that we might have emitted this already, + // e.g. with a typedef and a pointer to it. + llvm::Value *&entry = VLASizeMap[size]; + if (!entry) { + llvm::Value *Size = EmitScalarExpr(size); + + // C11 6.7.6.2p5: + // If the size is an expression that is not an integer constant + // expression [...] each time it is evaluated it shall have a value + // greater than zero. + if (SanOpts.has(SanitizerKind::VLABound) && + size->getType()->isSignedIntegerType()) { + SanitizerScope SanScope(this); + llvm::Value *Zero = llvm::Constant::getNullValue(Size->getType()); + llvm::Constant *StaticArgs[] = { + EmitCheckSourceLocation(size->getBeginLoc()), + EmitCheckTypeDescriptor(size->getType())}; + EmitCheck(std::make_pair(Builder.CreateICmpSGT(Size, Zero), + SanitizerKind::VLABound), + SanitizerHandler::VLABoundNotPositive, StaticArgs, Size); + } + + // Always zexting here would be wrong if it weren't + // undefined behavior to have a negative bound. + entry = Builder.CreateIntCast(Size, SizeTy, /*signed*/ false); + } + } + type = vat->getElementType(); + break; + } + + case Type::FunctionProto: + case Type::FunctionNoProto: + type = cast<FunctionType>(ty)->getReturnType(); + break; + + case Type::Paren: + case Type::TypeOf: + case Type::UnaryTransform: + case Type::Attributed: + case Type::SubstTemplateTypeParm: + case Type::PackExpansion: + case Type::MacroQualified: + // Keep walking after single level desugaring. + type = type.getSingleStepDesugaredType(getContext()); + break; + + case Type::Typedef: + case Type::Decltype: + case Type::Auto: + case Type::DeducedTemplateSpecialization: + // Stop walking: nothing to do. + return; + + case Type::TypeOfExpr: + // Stop walking: emit typeof expression. + EmitIgnoredExpr(cast<TypeOfExprType>(ty)->getUnderlyingExpr()); + return; + + case Type::Atomic: + type = cast<AtomicType>(ty)->getValueType(); + break; + + case Type::Pipe: + type = cast<PipeType>(ty)->getElementType(); + break; + } + } while (type->isVariablyModifiedType()); +} + +Address CodeGenFunction::EmitVAListRef(const Expr* E) { + if (getContext().getBuiltinVaListType()->isArrayType()) + return EmitPointerWithAlignment(E); + return EmitLValue(E).getAddress(*this); +} + +Address CodeGenFunction::EmitMSVAListRef(const Expr *E) { + return EmitLValue(E).getAddress(*this); +} + +void CodeGenFunction::EmitDeclRefExprDbgValue(const DeclRefExpr *E, + const APValue &Init) { + assert(Init.hasValue() && "Invalid DeclRefExpr initializer!"); + if (CGDebugInfo *Dbg = getDebugInfo()) + if (CGM.getCodeGenOpts().hasReducedDebugInfo()) + Dbg->EmitGlobalVariable(E->getDecl(), Init); +} + +CodeGenFunction::PeepholeProtection +CodeGenFunction::protectFromPeepholes(RValue rvalue) { + // At the moment, the only aggressive peephole we do in IR gen + // is trunc(zext) folding, but if we add more, we can easily + // extend this protection. + + if (!rvalue.isScalar()) return PeepholeProtection(); + llvm::Value *value = rvalue.getScalarVal(); + if (!isa<llvm::ZExtInst>(value)) return PeepholeProtection(); + + // Just make an extra bitcast. + assert(HaveInsertPoint()); + llvm::Instruction *inst = new llvm::BitCastInst(value, value->getType(), "", + Builder.GetInsertBlock()); + + PeepholeProtection protection; + protection.Inst = inst; + return protection; +} + +void CodeGenFunction::unprotectFromPeepholes(PeepholeProtection protection) { + if (!protection.Inst) return; + + // In theory, we could try to duplicate the peepholes now, but whatever. + protection.Inst->eraseFromParent(); +} + +void CodeGenFunction::EmitAlignmentAssumption(llvm::Value *PtrValue, + QualType Ty, SourceLocation Loc, + SourceLocation AssumptionLoc, + llvm::Value *Alignment, + llvm::Value *OffsetValue) { + llvm::Value *TheCheck; + llvm::Instruction *Assumption = Builder.CreateAlignmentAssumption( + CGM.getDataLayout(), PtrValue, Alignment, OffsetValue, &TheCheck); + if (SanOpts.has(SanitizerKind::Alignment)) { + EmitAlignmentAssumptionCheck(PtrValue, Ty, Loc, AssumptionLoc, Alignment, + OffsetValue, TheCheck, Assumption); + } +} + +void CodeGenFunction::EmitAlignmentAssumption(llvm::Value *PtrValue, + const Expr *E, + SourceLocation AssumptionLoc, + llvm::Value *Alignment, + llvm::Value *OffsetValue) { + if (auto *CE = dyn_cast<CastExpr>(E)) + E = CE->getSubExprAsWritten(); + QualType Ty = E->getType(); + SourceLocation Loc = E->getExprLoc(); + + EmitAlignmentAssumption(PtrValue, Ty, Loc, AssumptionLoc, Alignment, + OffsetValue); +} + +llvm::Value *CodeGenFunction::EmitAnnotationCall(llvm::Function *AnnotationFn, + llvm::Value *AnnotatedVal, + StringRef AnnotationStr, + SourceLocation Location) { + llvm::Value *Args[4] = { + AnnotatedVal, + Builder.CreateBitCast(CGM.EmitAnnotationString(AnnotationStr), Int8PtrTy), + Builder.CreateBitCast(CGM.EmitAnnotationUnit(Location), Int8PtrTy), + CGM.EmitAnnotationLineNo(Location) + }; + return Builder.CreateCall(AnnotationFn, Args); +} + +void CodeGenFunction::EmitVarAnnotations(const VarDecl *D, llvm::Value *V) { + assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute"); + // FIXME We create a new bitcast for every annotation because that's what + // llvm-gcc was doing. + for (const auto *I : D->specific_attrs<AnnotateAttr>()) + EmitAnnotationCall(CGM.getIntrinsic(llvm::Intrinsic::var_annotation), + Builder.CreateBitCast(V, CGM.Int8PtrTy, V->getName()), + I->getAnnotation(), D->getLocation()); +} + +Address CodeGenFunction::EmitFieldAnnotations(const FieldDecl *D, + Address Addr) { + assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute"); + llvm::Value *V = Addr.getPointer(); + llvm::Type *VTy = V->getType(); + llvm::Function *F = CGM.getIntrinsic(llvm::Intrinsic::ptr_annotation, + CGM.Int8PtrTy); + + for (const auto *I : D->specific_attrs<AnnotateAttr>()) { + // FIXME Always emit the cast inst so we can differentiate between + // annotation on the first field of a struct and annotation on the struct + // itself. + if (VTy != CGM.Int8PtrTy) + V = Builder.CreateBitCast(V, CGM.Int8PtrTy); + V = EmitAnnotationCall(F, V, I->getAnnotation(), D->getLocation()); + V = Builder.CreateBitCast(V, VTy); + } + + return Address(V, Addr.getAlignment()); +} + +CodeGenFunction::CGCapturedStmtInfo::~CGCapturedStmtInfo() { } + +CodeGenFunction::SanitizerScope::SanitizerScope(CodeGenFunction *CGF) + : CGF(CGF) { + assert(!CGF->IsSanitizerScope); + CGF->IsSanitizerScope = true; +} + +CodeGenFunction::SanitizerScope::~SanitizerScope() { + CGF->IsSanitizerScope = false; +} + +void CodeGenFunction::InsertHelper(llvm::Instruction *I, + const llvm::Twine &Name, + llvm::BasicBlock *BB, + llvm::BasicBlock::iterator InsertPt) const { + LoopStack.InsertHelper(I); + if (IsSanitizerScope) + CGM.getSanitizerMetadata()->disableSanitizerForInstruction(I); +} + +void CGBuilderInserter::InsertHelper( + llvm::Instruction *I, const llvm::Twine &Name, llvm::BasicBlock *BB, + llvm::BasicBlock::iterator InsertPt) const { + llvm::IRBuilderDefaultInserter::InsertHelper(I, Name, BB, InsertPt); + if (CGF) + CGF->InsertHelper(I, Name, BB, InsertPt); +} + +static bool hasRequiredFeatures(const SmallVectorImpl<StringRef> &ReqFeatures, + CodeGenModule &CGM, const FunctionDecl *FD, + std::string &FirstMissing) { + // If there aren't any required features listed then go ahead and return. + if (ReqFeatures.empty()) + return false; + + // Now build up the set of caller features and verify that all the required + // features are there. + llvm::StringMap<bool> CallerFeatureMap; + CGM.getContext().getFunctionFeatureMap(CallerFeatureMap, FD); + + // If we have at least one of the features in the feature list return + // true, otherwise return false. + return std::all_of( + ReqFeatures.begin(), ReqFeatures.end(), [&](StringRef Feature) { + SmallVector<StringRef, 1> OrFeatures; + Feature.split(OrFeatures, '|'); + return llvm::any_of(OrFeatures, [&](StringRef Feature) { + if (!CallerFeatureMap.lookup(Feature)) { + FirstMissing = Feature.str(); + return false; + } + return true; + }); + }); +} + +// Emits an error if we don't have a valid set of target features for the +// called function. +void CodeGenFunction::checkTargetFeatures(const CallExpr *E, + const FunctionDecl *TargetDecl) { + return checkTargetFeatures(E->getBeginLoc(), TargetDecl); +} + +// Emits an error if we don't have a valid set of target features for the +// called function. +void CodeGenFunction::checkTargetFeatures(SourceLocation Loc, + const FunctionDecl *TargetDecl) { + // Early exit if this is an indirect call. + if (!TargetDecl) + return; + + // Get the current enclosing function if it exists. If it doesn't + // we can't check the target features anyhow. + const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(CurCodeDecl); + if (!FD) + return; + + // Grab the required features for the call. For a builtin this is listed in + // the td file with the default cpu, for an always_inline function this is any + // listed cpu and any listed features. + unsigned BuiltinID = TargetDecl->getBuiltinID(); + std::string MissingFeature; + if (BuiltinID) { + SmallVector<StringRef, 1> ReqFeatures; + const char *FeatureList = + CGM.getContext().BuiltinInfo.getRequiredFeatures(BuiltinID); + // Return if the builtin doesn't have any required features. + if (!FeatureList || StringRef(FeatureList) == "") + return; + StringRef(FeatureList).split(ReqFeatures, ','); + if (!hasRequiredFeatures(ReqFeatures, CGM, FD, MissingFeature)) + CGM.getDiags().Report(Loc, diag::err_builtin_needs_feature) + << TargetDecl->getDeclName() + << CGM.getContext().BuiltinInfo.getRequiredFeatures(BuiltinID); + + } else if (!TargetDecl->isMultiVersion() && + TargetDecl->hasAttr<TargetAttr>()) { + // Get the required features for the callee. + + const TargetAttr *TD = TargetDecl->getAttr<TargetAttr>(); + ParsedTargetAttr ParsedAttr = + CGM.getContext().filterFunctionTargetAttrs(TD); + + SmallVector<StringRef, 1> ReqFeatures; + llvm::StringMap<bool> CalleeFeatureMap; + CGM.getContext().getFunctionFeatureMap(CalleeFeatureMap, + GlobalDecl(TargetDecl)); + + for (const auto &F : ParsedAttr.Features) { + if (F[0] == '+' && CalleeFeatureMap.lookup(F.substr(1))) + ReqFeatures.push_back(StringRef(F).substr(1)); + } + + for (const auto &F : CalleeFeatureMap) { + // Only positive features are "required". + if (F.getValue()) + ReqFeatures.push_back(F.getKey()); + } + if (!hasRequiredFeatures(ReqFeatures, CGM, FD, MissingFeature)) + CGM.getDiags().Report(Loc, diag::err_function_needs_feature) + << FD->getDeclName() << TargetDecl->getDeclName() << MissingFeature; + } +} + +void CodeGenFunction::EmitSanitizerStatReport(llvm::SanitizerStatKind SSK) { + if (!CGM.getCodeGenOpts().SanitizeStats) + return; + + llvm::IRBuilder<> IRB(Builder.GetInsertBlock(), Builder.GetInsertPoint()); + IRB.SetCurrentDebugLocation(Builder.getCurrentDebugLocation()); + CGM.getSanStats().create(IRB, SSK); +} + +llvm::Value * +CodeGenFunction::FormResolverCondition(const MultiVersionResolverOption &RO) { + llvm::Value *Condition = nullptr; + + if (!RO.Conditions.Architecture.empty()) + Condition = EmitX86CpuIs(RO.Conditions.Architecture); + + if (!RO.Conditions.Features.empty()) { + llvm::Value *FeatureCond = EmitX86CpuSupports(RO.Conditions.Features); + Condition = + Condition ? Builder.CreateAnd(Condition, FeatureCond) : FeatureCond; + } + return Condition; +} + +static void CreateMultiVersionResolverReturn(CodeGenModule &CGM, + llvm::Function *Resolver, + CGBuilderTy &Builder, + llvm::Function *FuncToReturn, + bool SupportsIFunc) { + if (SupportsIFunc) { + Builder.CreateRet(FuncToReturn); + return; + } + + llvm::SmallVector<llvm::Value *, 10> Args; + llvm::for_each(Resolver->args(), + [&](llvm::Argument &Arg) { Args.push_back(&Arg); }); + + llvm::CallInst *Result = Builder.CreateCall(FuncToReturn, Args); + Result->setTailCallKind(llvm::CallInst::TCK_MustTail); + + if (Resolver->getReturnType()->isVoidTy()) + Builder.CreateRetVoid(); + else + Builder.CreateRet(Result); +} + +void CodeGenFunction::EmitMultiVersionResolver( + llvm::Function *Resolver, ArrayRef<MultiVersionResolverOption> Options) { + assert(getContext().getTargetInfo().getTriple().isX86() && + "Only implemented for x86 targets"); + + bool SupportsIFunc = getContext().getTargetInfo().supportsIFunc(); + + // Main function's basic block. + llvm::BasicBlock *CurBlock = createBasicBlock("resolver_entry", Resolver); + Builder.SetInsertPoint(CurBlock); + EmitX86CpuInit(); + + for (const MultiVersionResolverOption &RO : Options) { + Builder.SetInsertPoint(CurBlock); + llvm::Value *Condition = FormResolverCondition(RO); + + // The 'default' or 'generic' case. + if (!Condition) { + assert(&RO == Options.end() - 1 && + "Default or Generic case must be last"); + CreateMultiVersionResolverReturn(CGM, Resolver, Builder, RO.Function, + SupportsIFunc); + return; + } + + llvm::BasicBlock *RetBlock = createBasicBlock("resolver_return", Resolver); + CGBuilderTy RetBuilder(*this, RetBlock); + CreateMultiVersionResolverReturn(CGM, Resolver, RetBuilder, RO.Function, + SupportsIFunc); + CurBlock = createBasicBlock("resolver_else", Resolver); + Builder.CreateCondBr(Condition, RetBlock, CurBlock); + } + + // If no generic/default, emit an unreachable. + Builder.SetInsertPoint(CurBlock); + llvm::CallInst *TrapCall = EmitTrapCall(llvm::Intrinsic::trap); + TrapCall->setDoesNotReturn(); + TrapCall->setDoesNotThrow(); + Builder.CreateUnreachable(); + Builder.ClearInsertionPoint(); +} + +// Loc - where the diagnostic will point, where in the source code this +// alignment has failed. +// SecondaryLoc - if present (will be present if sufficiently different from +// Loc), the diagnostic will additionally point a "Note:" to this location. +// It should be the location where the __attribute__((assume_aligned)) +// was written e.g. +void CodeGenFunction::EmitAlignmentAssumptionCheck( + llvm::Value *Ptr, QualType Ty, SourceLocation Loc, + SourceLocation SecondaryLoc, llvm::Value *Alignment, + llvm::Value *OffsetValue, llvm::Value *TheCheck, + llvm::Instruction *Assumption) { + assert(Assumption && isa<llvm::CallInst>(Assumption) && + cast<llvm::CallInst>(Assumption)->getCalledValue() == + llvm::Intrinsic::getDeclaration( + Builder.GetInsertBlock()->getParent()->getParent(), + llvm::Intrinsic::assume) && + "Assumption should be a call to llvm.assume()."); + assert(&(Builder.GetInsertBlock()->back()) == Assumption && + "Assumption should be the last instruction of the basic block, " + "since the basic block is still being generated."); + + if (!SanOpts.has(SanitizerKind::Alignment)) + return; + + // Don't check pointers to volatile data. The behavior here is implementation- + // defined. + if (Ty->getPointeeType().isVolatileQualified()) + return; + + // We need to temorairly remove the assumption so we can insert the + // sanitizer check before it, else the check will be dropped by optimizations. + Assumption->removeFromParent(); + + { + SanitizerScope SanScope(this); + + if (!OffsetValue) + OffsetValue = Builder.getInt1(0); // no offset. + + llvm::Constant *StaticData[] = {EmitCheckSourceLocation(Loc), + EmitCheckSourceLocation(SecondaryLoc), + EmitCheckTypeDescriptor(Ty)}; + llvm::Value *DynamicData[] = {EmitCheckValue(Ptr), + EmitCheckValue(Alignment), + EmitCheckValue(OffsetValue)}; + EmitCheck({std::make_pair(TheCheck, SanitizerKind::Alignment)}, + SanitizerHandler::AlignmentAssumption, StaticData, DynamicData); + } + + // We are now in the (new, empty) "cont" basic block. + // Reintroduce the assumption. + Builder.Insert(Assumption); + // FIXME: Assumption still has it's original basic block as it's Parent. +} + +llvm::DebugLoc CodeGenFunction::SourceLocToDebugLoc(SourceLocation Location) { + if (CGDebugInfo *DI = getDebugInfo()) + return DI->SourceLocToDebugLoc(Location); + + return llvm::DebugLoc(); +} |