//===--- CGExpr.cpp - Emit LLVM Code from Expressions ---------------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This contains code to emit Expr nodes as LLVM code. // //===----------------------------------------------------------------------===// #include "CGCXXABI.h" #include "CGCall.h" #include "CGCleanup.h" #include "CGDebugInfo.h" #include "CGObjCRuntime.h" #include "CGOpenMPRuntime.h" #include "CGRecordLayout.h" #include "CodeGenFunction.h" #include "CodeGenModule.h" #include "ConstantEmitter.h" #include "TargetInfo.h" #include "clang/AST/ASTContext.h" #include "clang/AST/Attr.h" #include "clang/AST/DeclObjC.h" #include "clang/AST/NSAPI.h" #include "clang/Frontend/CodeGenOptions.h" #include "llvm/ADT/Hashing.h" #include "llvm/ADT/StringExtras.h" #include "llvm/IR/DataLayout.h" #include "llvm/IR/Intrinsics.h" #include "llvm/IR/LLVMContext.h" #include "llvm/IR/MDBuilder.h" #include "llvm/Support/ConvertUTF.h" #include "llvm/Support/MathExtras.h" #include "llvm/Support/Path.h" #include "llvm/Transforms/Utils/SanitizerStats.h" #include using namespace clang; using namespace CodeGen; //===--------------------------------------------------------------------===// // Miscellaneous Helper Methods //===--------------------------------------------------------------------===// llvm::Value *CodeGenFunction::EmitCastToVoidPtr(llvm::Value *value) { unsigned addressSpace = cast(value->getType())->getAddressSpace(); llvm::PointerType *destType = Int8PtrTy; if (addressSpace) destType = llvm::Type::getInt8PtrTy(getLLVMContext(), addressSpace); if (value->getType() == destType) return value; return Builder.CreateBitCast(value, destType); } /// CreateTempAlloca - This creates a alloca and inserts it into the entry /// block. Address CodeGenFunction::CreateTempAllocaWithoutCast(llvm::Type *Ty, CharUnits Align, const Twine &Name, llvm::Value *ArraySize) { auto Alloca = CreateTempAlloca(Ty, Name, ArraySize); Alloca->setAlignment(Align.getQuantity()); return Address(Alloca, Align); } /// CreateTempAlloca - This creates a alloca and inserts it into the entry /// block. The alloca is casted to default address space if necessary. Address CodeGenFunction::CreateTempAlloca(llvm::Type *Ty, CharUnits Align, const Twine &Name, llvm::Value *ArraySize, Address *AllocaAddr) { auto Alloca = CreateTempAllocaWithoutCast(Ty, Align, Name, ArraySize); if (AllocaAddr) *AllocaAddr = Alloca; llvm::Value *V = Alloca.getPointer(); // Alloca always returns a pointer in alloca address space, which may // be different from the type defined by the language. For example, // in C++ the auto variables are in the default address space. Therefore // cast alloca to the default address space when necessary. if (getASTAllocaAddressSpace() != LangAS::Default) { auto DestAddrSpace = getContext().getTargetAddressSpace(LangAS::Default); llvm::IRBuilderBase::InsertPointGuard IPG(Builder); // When ArraySize is nullptr, alloca is inserted at AllocaInsertPt, // otherwise alloca is inserted at the current insertion point of the // builder. if (!ArraySize) Builder.SetInsertPoint(AllocaInsertPt); V = getTargetHooks().performAddrSpaceCast( *this, V, getASTAllocaAddressSpace(), LangAS::Default, Ty->getPointerTo(DestAddrSpace), /*non-null*/ true); } return Address(V, Align); } /// CreateTempAlloca - This creates an alloca and inserts it into the entry /// block if \p ArraySize is nullptr, otherwise inserts it at the current /// insertion point of the builder. llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(llvm::Type *Ty, const Twine &Name, llvm::Value *ArraySize) { if (ArraySize) return Builder.CreateAlloca(Ty, ArraySize, Name); return new llvm::AllocaInst(Ty, CGM.getDataLayout().getAllocaAddrSpace(), ArraySize, Name, AllocaInsertPt); } /// CreateDefaultAlignTempAlloca - This creates an alloca with the /// default alignment of the corresponding LLVM type, which is *not* /// guaranteed to be related in any way to the expected alignment of /// an AST type that might have been lowered to Ty. Address CodeGenFunction::CreateDefaultAlignTempAlloca(llvm::Type *Ty, const Twine &Name) { CharUnits Align = CharUnits::fromQuantity(CGM.getDataLayout().getABITypeAlignment(Ty)); return CreateTempAlloca(Ty, Align, Name); } void CodeGenFunction::InitTempAlloca(Address Var, llvm::Value *Init) { assert(isa(Var.getPointer())); auto *Store = new llvm::StoreInst(Init, Var.getPointer()); Store->setAlignment(Var.getAlignment().getQuantity()); llvm::BasicBlock *Block = AllocaInsertPt->getParent(); Block->getInstList().insertAfter(AllocaInsertPt->getIterator(), Store); } Address CodeGenFunction::CreateIRTemp(QualType Ty, const Twine &Name) { CharUnits Align = getContext().getTypeAlignInChars(Ty); return CreateTempAlloca(ConvertType(Ty), Align, Name); } Address CodeGenFunction::CreateMemTemp(QualType Ty, const Twine &Name, Address *Alloca) { // FIXME: Should we prefer the preferred type alignment here? return CreateMemTemp(Ty, getContext().getTypeAlignInChars(Ty), Name, Alloca); } Address CodeGenFunction::CreateMemTemp(QualType Ty, CharUnits Align, const Twine &Name, Address *Alloca) { return CreateTempAlloca(ConvertTypeForMem(Ty), Align, Name, /*ArraySize=*/nullptr, Alloca); } Address CodeGenFunction::CreateMemTempWithoutCast(QualType Ty, CharUnits Align, const Twine &Name) { return CreateTempAllocaWithoutCast(ConvertTypeForMem(Ty), Align, Name); } Address CodeGenFunction::CreateMemTempWithoutCast(QualType Ty, const Twine &Name) { return CreateMemTempWithoutCast(Ty, getContext().getTypeAlignInChars(Ty), Name); } /// EvaluateExprAsBool - Perform the usual unary conversions on the specified /// expression and compare the result against zero, returning an Int1Ty value. llvm::Value *CodeGenFunction::EvaluateExprAsBool(const Expr *E) { PGO.setCurrentStmt(E); if (const MemberPointerType *MPT = E->getType()->getAs()) { llvm::Value *MemPtr = EmitScalarExpr(E); return CGM.getCXXABI().EmitMemberPointerIsNotNull(*this, MemPtr, MPT); } QualType BoolTy = getContext().BoolTy; SourceLocation Loc = E->getExprLoc(); if (!E->getType()->isAnyComplexType()) return EmitScalarConversion(EmitScalarExpr(E), E->getType(), BoolTy, Loc); return EmitComplexToScalarConversion(EmitComplexExpr(E), E->getType(), BoolTy, Loc); } /// EmitIgnoredExpr - Emit code to compute the specified expression, /// ignoring the result. void CodeGenFunction::EmitIgnoredExpr(const Expr *E) { if (E->isRValue()) return (void) EmitAnyExpr(E, AggValueSlot::ignored(), true); // Just emit it as an l-value and drop the result. EmitLValue(E); } /// EmitAnyExpr - Emit code to compute the specified expression which /// can have any type. The result is returned as an RValue struct. /// If this is an aggregate expression, AggSlot indicates where the /// result should be returned. RValue CodeGenFunction::EmitAnyExpr(const Expr *E, AggValueSlot aggSlot, bool ignoreResult) { switch (getEvaluationKind(E->getType())) { case TEK_Scalar: return RValue::get(EmitScalarExpr(E, ignoreResult)); case TEK_Complex: return RValue::getComplex(EmitComplexExpr(E, ignoreResult, ignoreResult)); case TEK_Aggregate: if (!ignoreResult && aggSlot.isIgnored()) aggSlot = CreateAggTemp(E->getType(), "agg-temp"); EmitAggExpr(E, aggSlot); return aggSlot.asRValue(); } llvm_unreachable("bad evaluation kind"); } /// EmitAnyExprToTemp - Similar to EmitAnyExpr(), however, the result will /// always be accessible even if no aggregate location is provided. RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E) { AggValueSlot AggSlot = AggValueSlot::ignored(); if (hasAggregateEvaluationKind(E->getType())) AggSlot = CreateAggTemp(E->getType(), "agg.tmp"); return EmitAnyExpr(E, AggSlot); } /// EmitAnyExprToMem - Evaluate an expression into a given memory /// location. void CodeGenFunction::EmitAnyExprToMem(const Expr *E, Address Location, Qualifiers Quals, bool IsInit) { // FIXME: This function should take an LValue as an argument. switch (getEvaluationKind(E->getType())) { case TEK_Complex: EmitComplexExprIntoLValue(E, MakeAddrLValue(Location, E->getType()), /*isInit*/ false); return; case TEK_Aggregate: { EmitAggExpr(E, AggValueSlot::forAddr(Location, Quals, AggValueSlot::IsDestructed_t(IsInit), AggValueSlot::DoesNotNeedGCBarriers, AggValueSlot::IsAliased_t(!IsInit), AggValueSlot::MayOverlap)); return; } case TEK_Scalar: { RValue RV = RValue::get(EmitScalarExpr(E, /*Ignore*/ false)); LValue LV = MakeAddrLValue(Location, E->getType()); EmitStoreThroughLValue(RV, LV); return; } } llvm_unreachable("bad evaluation kind"); } static void pushTemporaryCleanup(CodeGenFunction &CGF, const MaterializeTemporaryExpr *M, const Expr *E, Address ReferenceTemporary) { // Objective-C++ ARC: // If we are binding a reference to a temporary that has ownership, we // need to perform retain/release operations on the temporary. // // FIXME: This should be looking at E, not M. if (auto Lifetime = M->getType().getObjCLifetime()) { switch (Lifetime) { case Qualifiers::OCL_None: case Qualifiers::OCL_ExplicitNone: // Carry on to normal cleanup handling. break; case Qualifiers::OCL_Autoreleasing: // Nothing to do; cleaned up by an autorelease pool. return; case Qualifiers::OCL_Strong: case Qualifiers::OCL_Weak: switch (StorageDuration Duration = M->getStorageDuration()) { case SD_Static: // Note: we intentionally do not register a cleanup to release // the object on program termination. return; case SD_Thread: // FIXME: We should probably register a cleanup in this case. return; case SD_Automatic: case SD_FullExpression: CodeGenFunction::Destroyer *Destroy; CleanupKind CleanupKind; if (Lifetime == Qualifiers::OCL_Strong) { const ValueDecl *VD = M->getExtendingDecl(); bool Precise = VD && isa(VD) && VD->hasAttr(); CleanupKind = CGF.getARCCleanupKind(); Destroy = Precise ? &CodeGenFunction::destroyARCStrongPrecise : &CodeGenFunction::destroyARCStrongImprecise; } else { // __weak objects always get EH cleanups; otherwise, exceptions // could cause really nasty crashes instead of mere leaks. CleanupKind = NormalAndEHCleanup; Destroy = &CodeGenFunction::destroyARCWeak; } if (Duration == SD_FullExpression) CGF.pushDestroy(CleanupKind, ReferenceTemporary, M->getType(), *Destroy, CleanupKind & EHCleanup); else CGF.pushLifetimeExtendedDestroy(CleanupKind, ReferenceTemporary, M->getType(), *Destroy, CleanupKind & EHCleanup); return; case SD_Dynamic: llvm_unreachable("temporary cannot have dynamic storage duration"); } llvm_unreachable("unknown storage duration"); } } CXXDestructorDecl *ReferenceTemporaryDtor = nullptr; if (const RecordType *RT = E->getType()->getBaseElementTypeUnsafe()->getAs()) { // Get the destructor for the reference temporary. auto *ClassDecl = cast(RT->getDecl()); if (!ClassDecl->hasTrivialDestructor()) ReferenceTemporaryDtor = ClassDecl->getDestructor(); } if (!ReferenceTemporaryDtor) return; // Call the destructor for the temporary. switch (M->getStorageDuration()) { case SD_Static: case SD_Thread: { llvm::Constant *CleanupFn; llvm::Constant *CleanupArg; if (E->getType()->isArrayType()) { CleanupFn = CodeGenFunction(CGF.CGM).generateDestroyHelper( ReferenceTemporary, E->getType(), CodeGenFunction::destroyCXXObject, CGF.getLangOpts().Exceptions, dyn_cast_or_null(M->getExtendingDecl())); CleanupArg = llvm::Constant::getNullValue(CGF.Int8PtrTy); } else { CleanupFn = CGF.CGM.getAddrOfCXXStructor(ReferenceTemporaryDtor, StructorType::Complete); CleanupArg = cast(ReferenceTemporary.getPointer()); } CGF.CGM.getCXXABI().registerGlobalDtor( CGF, *cast(M->getExtendingDecl()), CleanupFn, CleanupArg); break; } case SD_FullExpression: CGF.pushDestroy(NormalAndEHCleanup, ReferenceTemporary, E->getType(), CodeGenFunction::destroyCXXObject, CGF.getLangOpts().Exceptions); break; case SD_Automatic: CGF.pushLifetimeExtendedDestroy(NormalAndEHCleanup, ReferenceTemporary, E->getType(), CodeGenFunction::destroyCXXObject, CGF.getLangOpts().Exceptions); break; case SD_Dynamic: llvm_unreachable("temporary cannot have dynamic storage duration"); } } static Address createReferenceTemporary(CodeGenFunction &CGF, const MaterializeTemporaryExpr *M, const Expr *Inner, Address *Alloca = nullptr) { auto &TCG = CGF.getTargetHooks(); switch (M->getStorageDuration()) { case SD_FullExpression: case SD_Automatic: { // If we have a constant temporary array or record try to promote it into a // constant global under the same rules a normal constant would've been // promoted. This is easier on the optimizer and generally emits fewer // instructions. QualType Ty = Inner->getType(); if (CGF.CGM.getCodeGenOpts().MergeAllConstants && (Ty->isArrayType() || Ty->isRecordType()) && CGF.CGM.isTypeConstant(Ty, true)) if (auto Init = ConstantEmitter(CGF).tryEmitAbstract(Inner, Ty)) { if (auto AddrSpace = CGF.getTarget().getConstantAddressSpace()) { auto AS = AddrSpace.getValue(); auto *GV = new llvm::GlobalVariable( CGF.CGM.getModule(), Init->getType(), /*isConstant=*/true, llvm::GlobalValue::PrivateLinkage, Init, ".ref.tmp", nullptr, llvm::GlobalValue::NotThreadLocal, CGF.getContext().getTargetAddressSpace(AS)); CharUnits alignment = CGF.getContext().getTypeAlignInChars(Ty); GV->setAlignment(alignment.getQuantity()); llvm::Constant *C = GV; if (AS != LangAS::Default) C = TCG.performAddrSpaceCast( CGF.CGM, GV, AS, LangAS::Default, GV->getValueType()->getPointerTo( CGF.getContext().getTargetAddressSpace(LangAS::Default))); // FIXME: Should we put the new global into a COMDAT? return Address(C, alignment); } } return CGF.CreateMemTemp(Ty, "ref.tmp", Alloca); } case SD_Thread: case SD_Static: return CGF.CGM.GetAddrOfGlobalTemporary(M, Inner); case SD_Dynamic: llvm_unreachable("temporary can't have dynamic storage duration"); } llvm_unreachable("unknown storage duration"); } LValue CodeGenFunction:: EmitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *M) { const Expr *E = M->GetTemporaryExpr(); // FIXME: ideally this would use EmitAnyExprToMem, however, we cannot do so // as that will cause the lifetime adjustment to be lost for ARC auto ownership = M->getType().getObjCLifetime(); if (ownership != Qualifiers::OCL_None && ownership != Qualifiers::OCL_ExplicitNone) { Address Object = createReferenceTemporary(*this, M, E); if (auto *Var = dyn_cast(Object.getPointer())) { Object = Address(llvm::ConstantExpr::getBitCast(Var, ConvertTypeForMem(E->getType()) ->getPointerTo(Object.getAddressSpace())), Object.getAlignment()); // createReferenceTemporary will promote the temporary to a global with a // constant initializer if it can. It can only do this to a value of // ARC-manageable type if the value is global and therefore "immune" to // ref-counting operations. Therefore we have no need to emit either a // dynamic initialization or a cleanup and we can just return the address // of the temporary. if (Var->hasInitializer()) return MakeAddrLValue(Object, M->getType(), AlignmentSource::Decl); Var->setInitializer(CGM.EmitNullConstant(E->getType())); } LValue RefTempDst = MakeAddrLValue(Object, M->getType(), AlignmentSource::Decl); switch (getEvaluationKind(E->getType())) { default: llvm_unreachable("expected scalar or aggregate expression"); case TEK_Scalar: EmitScalarInit(E, M->getExtendingDecl(), RefTempDst, false); break; case TEK_Aggregate: { EmitAggExpr(E, AggValueSlot::forAddr(Object, E->getType().getQualifiers(), AggValueSlot::IsDestructed, AggValueSlot::DoesNotNeedGCBarriers, AggValueSlot::IsNotAliased, AggValueSlot::DoesNotOverlap)); break; } } pushTemporaryCleanup(*this, M, E, Object); return RefTempDst; } SmallVector CommaLHSs; SmallVector Adjustments; E = E->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments); for (const auto &Ignored : CommaLHSs) EmitIgnoredExpr(Ignored); if (const auto *opaque = dyn_cast(E)) { if (opaque->getType()->isRecordType()) { assert(Adjustments.empty()); return EmitOpaqueValueLValue(opaque); } } // Create and initialize the reference temporary. Address Alloca = Address::invalid(); Address Object = createReferenceTemporary(*this, M, E, &Alloca); if (auto *Var = dyn_cast( Object.getPointer()->stripPointerCasts())) { Object = Address(llvm::ConstantExpr::getBitCast( cast(Object.getPointer()), ConvertTypeForMem(E->getType())->getPointerTo()), Object.getAlignment()); // If the temporary is a global and has a constant initializer or is a // constant temporary that we promoted to a global, we may have already // initialized it. if (!Var->hasInitializer()) { Var->setInitializer(CGM.EmitNullConstant(E->getType())); EmitAnyExprToMem(E, Object, Qualifiers(), /*IsInit*/true); } } else { switch (M->getStorageDuration()) { case SD_Automatic: case SD_FullExpression: if (auto *Size = EmitLifetimeStart( CGM.getDataLayout().getTypeAllocSize(Alloca.getElementType()), Alloca.getPointer())) { if (M->getStorageDuration() == SD_Automatic) pushCleanupAfterFullExpr(NormalEHLifetimeMarker, Alloca, Size); else pushFullExprCleanup(NormalEHLifetimeMarker, Alloca, Size); } break; default: break; } EmitAnyExprToMem(E, Object, Qualifiers(), /*IsInit*/true); } pushTemporaryCleanup(*this, M, E, Object); // Perform derived-to-base casts and/or field accesses, to get from the // temporary object we created (and, potentially, for which we extended // the lifetime) to the subobject we're binding the reference to. for (unsigned I = Adjustments.size(); I != 0; --I) { SubobjectAdjustment &Adjustment = Adjustments[I-1]; switch (Adjustment.Kind) { case SubobjectAdjustment::DerivedToBaseAdjustment: Object = GetAddressOfBaseClass(Object, Adjustment.DerivedToBase.DerivedClass, Adjustment.DerivedToBase.BasePath->path_begin(), Adjustment.DerivedToBase.BasePath->path_end(), /*NullCheckValue=*/ false, E->getExprLoc()); break; case SubobjectAdjustment::FieldAdjustment: { LValue LV = MakeAddrLValue(Object, E->getType(), AlignmentSource::Decl); LV = EmitLValueForField(LV, Adjustment.Field); assert(LV.isSimple() && "materialized temporary field is not a simple lvalue"); Object = LV.getAddress(); break; } case SubobjectAdjustment::MemberPointerAdjustment: { llvm::Value *Ptr = EmitScalarExpr(Adjustment.Ptr.RHS); Object = EmitCXXMemberDataPointerAddress(E, Object, Ptr, Adjustment.Ptr.MPT); break; } } } return MakeAddrLValue(Object, M->getType(), AlignmentSource::Decl); } RValue CodeGenFunction::EmitReferenceBindingToExpr(const Expr *E) { // Emit the expression as an lvalue. LValue LV = EmitLValue(E); assert(LV.isSimple()); llvm::Value *Value = LV.getPointer(); if (sanitizePerformTypeCheck() && !E->getType()->isFunctionType()) { // C++11 [dcl.ref]p5 (as amended by core issue 453): // If a glvalue to which a reference is directly bound designates neither // an existing object or function of an appropriate type nor a region of // storage of suitable size and alignment to contain an object of the // reference's type, the behavior is undefined. QualType Ty = E->getType(); EmitTypeCheck(TCK_ReferenceBinding, E->getExprLoc(), Value, Ty); } return RValue::get(Value); } /// getAccessedFieldNo - Given an encoded value and a result number, return the /// input field number being accessed. unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx, const llvm::Constant *Elts) { return cast(Elts->getAggregateElement(Idx)) ->getZExtValue(); } /// Emit the hash_16_bytes function from include/llvm/ADT/Hashing.h. static llvm::Value *emitHash16Bytes(CGBuilderTy &Builder, llvm::Value *Low, llvm::Value *High) { llvm::Value *KMul = Builder.getInt64(0x9ddfea08eb382d69ULL); llvm::Value *K47 = Builder.getInt64(47); llvm::Value *A0 = Builder.CreateMul(Builder.CreateXor(Low, High), KMul); llvm::Value *A1 = Builder.CreateXor(Builder.CreateLShr(A0, K47), A0); llvm::Value *B0 = Builder.CreateMul(Builder.CreateXor(High, A1), KMul); llvm::Value *B1 = Builder.CreateXor(Builder.CreateLShr(B0, K47), B0); return Builder.CreateMul(B1, KMul); } bool CodeGenFunction::isNullPointerAllowed(TypeCheckKind TCK) { return TCK == TCK_DowncastPointer || TCK == TCK_Upcast || TCK == TCK_UpcastToVirtualBase || TCK == TCK_DynamicOperation; } bool CodeGenFunction::isVptrCheckRequired(TypeCheckKind TCK, QualType Ty) { CXXRecordDecl *RD = Ty->getAsCXXRecordDecl(); return (RD && RD->hasDefinition() && RD->isDynamicClass()) && (TCK == TCK_MemberAccess || TCK == TCK_MemberCall || TCK == TCK_DowncastPointer || TCK == TCK_DowncastReference || TCK == TCK_UpcastToVirtualBase || TCK == TCK_DynamicOperation); } bool CodeGenFunction::sanitizePerformTypeCheck() const { return SanOpts.has(SanitizerKind::Null) | SanOpts.has(SanitizerKind::Alignment) | SanOpts.has(SanitizerKind::ObjectSize) | SanOpts.has(SanitizerKind::Vptr); } void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc, llvm::Value *Ptr, QualType Ty, CharUnits Alignment, SanitizerSet SkippedChecks) { if (!sanitizePerformTypeCheck()) return; // Don't check pointers outside the default address space. The null check // isn't correct, the object-size check isn't supported by LLVM, and we can't // communicate the addresses to the runtime handler for the vptr check. if (Ptr->getType()->getPointerAddressSpace()) return; // Don't check pointers to volatile data. The behavior here is implementation- // defined. if (Ty.isVolatileQualified()) return; SanitizerScope SanScope(this); SmallVector, 3> Checks; llvm::BasicBlock *Done = nullptr; // Quickly determine whether we have a pointer to an alloca. It's possible // to skip null checks, and some alignment checks, for these pointers. This // can reduce compile-time significantly. auto PtrToAlloca = dyn_cast(Ptr->stripPointerCastsNoFollowAliases()); llvm::Value *True = llvm::ConstantInt::getTrue(getLLVMContext()); llvm::Value *IsNonNull = nullptr; bool IsGuaranteedNonNull = SkippedChecks.has(SanitizerKind::Null) || PtrToAlloca; bool AllowNullPointers = isNullPointerAllowed(TCK); if ((SanOpts.has(SanitizerKind::Null) || AllowNullPointers) && !IsGuaranteedNonNull) { // The glvalue must not be an empty glvalue. IsNonNull = Builder.CreateIsNotNull(Ptr); // The IR builder can constant-fold the null check if the pointer points to // a constant. IsGuaranteedNonNull = IsNonNull == True; // Skip the null check if the pointer is known to be non-null. if (!IsGuaranteedNonNull) { if (AllowNullPointers) { // When performing pointer casts, it's OK if the value is null. // Skip the remaining checks in that case. Done = createBasicBlock("null"); llvm::BasicBlock *Rest = createBasicBlock("not.null"); Builder.CreateCondBr(IsNonNull, Rest, Done); EmitBlock(Rest); } else { Checks.push_back(std::make_pair(IsNonNull, SanitizerKind::Null)); } } } if (SanOpts.has(SanitizerKind::ObjectSize) && !SkippedChecks.has(SanitizerKind::ObjectSize) && !Ty->isIncompleteType()) { uint64_t Size = getContext().getTypeSizeInChars(Ty).getQuantity(); // The glvalue must refer to a large enough storage region. // FIXME: If Address Sanitizer is enabled, insert dynamic instrumentation // to check this. // FIXME: Get object address space llvm::Type *Tys[2] = { IntPtrTy, Int8PtrTy }; llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, Tys); llvm::Value *Min = Builder.getFalse(); llvm::Value *NullIsUnknown = Builder.getFalse(); llvm::Value *CastAddr = Builder.CreateBitCast(Ptr, Int8PtrTy); llvm::Value *LargeEnough = Builder.CreateICmpUGE( Builder.CreateCall(F, {CastAddr, Min, NullIsUnknown}), llvm::ConstantInt::get(IntPtrTy, Size)); Checks.push_back(std::make_pair(LargeEnough, SanitizerKind::ObjectSize)); } uint64_t AlignVal = 0; llvm::Value *PtrAsInt = nullptr; if (SanOpts.has(SanitizerKind::Alignment) && !SkippedChecks.has(SanitizerKind::Alignment)) { AlignVal = Alignment.getQuantity(); if (!Ty->isIncompleteType() && !AlignVal) AlignVal = getContext().getTypeAlignInChars(Ty).getQuantity(); // The glvalue must be suitably aligned. if (AlignVal > 1 && (!PtrToAlloca || PtrToAlloca->getAlignment() < AlignVal)) { PtrAsInt = Builder.CreatePtrToInt(Ptr, IntPtrTy); llvm::Value *Align = Builder.CreateAnd( PtrAsInt, llvm::ConstantInt::get(IntPtrTy, AlignVal - 1)); llvm::Value *Aligned = Builder.CreateICmpEQ(Align, llvm::ConstantInt::get(IntPtrTy, 0)); if (Aligned != True) Checks.push_back(std::make_pair(Aligned, SanitizerKind::Alignment)); } } if (Checks.size() > 0) { // Make sure we're not losing information. Alignment needs to be a power of // 2 assert(!AlignVal || (uint64_t)1 << llvm::Log2_64(AlignVal) == AlignVal); llvm::Constant *StaticData[] = { EmitCheckSourceLocation(Loc), EmitCheckTypeDescriptor(Ty), llvm::ConstantInt::get(Int8Ty, AlignVal ? llvm::Log2_64(AlignVal) : 1), llvm::ConstantInt::get(Int8Ty, TCK)}; EmitCheck(Checks, SanitizerHandler::TypeMismatch, StaticData, PtrAsInt ? PtrAsInt : Ptr); } // If possible, check that the vptr indicates that there is a subobject of // type Ty at offset zero within this object. // // C++11 [basic.life]p5,6: // [For storage which does not refer to an object within its lifetime] // The program has undefined behavior if: // -- the [pointer or glvalue] is used to access a non-static data member // or call a non-static member function if (SanOpts.has(SanitizerKind::Vptr) && !SkippedChecks.has(SanitizerKind::Vptr) && isVptrCheckRequired(TCK, Ty)) { // Ensure that the pointer is non-null before loading it. If there is no // compile-time guarantee, reuse the run-time null check or emit a new one. if (!IsGuaranteedNonNull) { if (!IsNonNull) IsNonNull = Builder.CreateIsNotNull(Ptr); if (!Done) Done = createBasicBlock("vptr.null"); llvm::BasicBlock *VptrNotNull = createBasicBlock("vptr.not.null"); Builder.CreateCondBr(IsNonNull, VptrNotNull, Done); EmitBlock(VptrNotNull); } // Compute a hash of the mangled name of the type. // // FIXME: This is not guaranteed to be deterministic! Move to a // fingerprinting mechanism once LLVM provides one. For the time // being the implementation happens to be deterministic. SmallString<64> MangledName; llvm::raw_svector_ostream Out(MangledName); CGM.getCXXABI().getMangleContext().mangleCXXRTTI(Ty.getUnqualifiedType(), Out); // Blacklist based on the mangled type. if (!CGM.getContext().getSanitizerBlacklist().isBlacklistedType( SanitizerKind::Vptr, Out.str())) { llvm::hash_code TypeHash = hash_value(Out.str()); // Load the vptr, and compute hash_16_bytes(TypeHash, vptr). llvm::Value *Low = llvm::ConstantInt::get(Int64Ty, TypeHash); llvm::Type *VPtrTy = llvm::PointerType::get(IntPtrTy, 0); Address VPtrAddr(Builder.CreateBitCast(Ptr, VPtrTy), getPointerAlign()); llvm::Value *VPtrVal = Builder.CreateLoad(VPtrAddr); llvm::Value *High = Builder.CreateZExt(VPtrVal, Int64Ty); llvm::Value *Hash = emitHash16Bytes(Builder, Low, High); Hash = Builder.CreateTrunc(Hash, IntPtrTy); // Look the hash up in our cache. const int CacheSize = 128; llvm::Type *HashTable = llvm::ArrayType::get(IntPtrTy, CacheSize); llvm::Value *Cache = CGM.CreateRuntimeVariable(HashTable, "__ubsan_vptr_type_cache"); llvm::Value *Slot = Builder.CreateAnd(Hash, llvm::ConstantInt::get(IntPtrTy, CacheSize-1)); llvm::Value *Indices[] = { Builder.getInt32(0), Slot }; llvm::Value *CacheVal = Builder.CreateAlignedLoad(Builder.CreateInBoundsGEP(Cache, Indices), getPointerAlign()); // If the hash isn't in the cache, call a runtime handler to perform the // hard work of checking whether the vptr is for an object of the right // type. This will either fill in the cache and return, or produce a // diagnostic. llvm::Value *EqualHash = Builder.CreateICmpEQ(CacheVal, Hash); llvm::Constant *StaticData[] = { EmitCheckSourceLocation(Loc), EmitCheckTypeDescriptor(Ty), CGM.GetAddrOfRTTIDescriptor(Ty.getUnqualifiedType()), llvm::ConstantInt::get(Int8Ty, TCK) }; llvm::Value *DynamicData[] = { Ptr, Hash }; EmitCheck(std::make_pair(EqualHash, SanitizerKind::Vptr), SanitizerHandler::DynamicTypeCacheMiss, StaticData, DynamicData); } } if (Done) { Builder.CreateBr(Done); EmitBlock(Done); } } /// Determine whether this expression refers to a flexible array member in a /// struct. We disable array bounds checks for such members. static bool isFlexibleArrayMemberExpr(const Expr *E) { // For compatibility with existing code, we treat arrays of length 0 or // 1 as flexible array members. const ArrayType *AT = E->getType()->castAsArrayTypeUnsafe(); if (const auto *CAT = dyn_cast(AT)) { if (CAT->getSize().ugt(1)) return false; } else if (!isa(AT)) return false; E = E->IgnoreParens(); // A flexible array member must be the last member in the class. if (const auto *ME = dyn_cast(E)) { // FIXME: If the base type of the member expr is not FD->getParent(), // this should not be treated as a flexible array member access. if (const auto *FD = dyn_cast(ME->getMemberDecl())) { RecordDecl::field_iterator FI( DeclContext::decl_iterator(const_cast(FD))); return ++FI == FD->getParent()->field_end(); } } else if (const auto *IRE = dyn_cast(E)) { return IRE->getDecl()->getNextIvar() == nullptr; } return false; } llvm::Value *CodeGenFunction::LoadPassedObjectSize(const Expr *E, QualType EltTy) { ASTContext &C = getContext(); uint64_t EltSize = C.getTypeSizeInChars(EltTy).getQuantity(); if (!EltSize) return nullptr; auto *ArrayDeclRef = dyn_cast(E->IgnoreParenImpCasts()); if (!ArrayDeclRef) return nullptr; auto *ParamDecl = dyn_cast(ArrayDeclRef->getDecl()); if (!ParamDecl) return nullptr; auto *POSAttr = ParamDecl->getAttr(); if (!POSAttr) return nullptr; // Don't load the size if it's a lower bound. int POSType = POSAttr->getType(); if (POSType != 0 && POSType != 1) return nullptr; // Find the implicit size parameter. auto PassedSizeIt = SizeArguments.find(ParamDecl); if (PassedSizeIt == SizeArguments.end()) return nullptr; const ImplicitParamDecl *PassedSizeDecl = PassedSizeIt->second; assert(LocalDeclMap.count(PassedSizeDecl) && "Passed size not loadable"); Address AddrOfSize = LocalDeclMap.find(PassedSizeDecl)->second; llvm::Value *SizeInBytes = EmitLoadOfScalar(AddrOfSize, /*Volatile=*/false, C.getSizeType(), E->getExprLoc()); llvm::Value *SizeOfElement = llvm::ConstantInt::get(SizeInBytes->getType(), EltSize); return Builder.CreateUDiv(SizeInBytes, SizeOfElement); } /// If Base is known to point to the start of an array, return the length of /// that array. Return 0 if the length cannot be determined. static llvm::Value *getArrayIndexingBound( CodeGenFunction &CGF, const Expr *Base, QualType &IndexedType) { // For the vector indexing extension, the bound is the number of elements. if (const VectorType *VT = Base->getType()->getAs()) { IndexedType = Base->getType(); return CGF.Builder.getInt32(VT->getNumElements()); } Base = Base->IgnoreParens(); if (const auto *CE = dyn_cast(Base)) { if (CE->getCastKind() == CK_ArrayToPointerDecay && !isFlexibleArrayMemberExpr(CE->getSubExpr())) { IndexedType = CE->getSubExpr()->getType(); const ArrayType *AT = IndexedType->castAsArrayTypeUnsafe(); if (const auto *CAT = dyn_cast(AT)) return CGF.Builder.getInt(CAT->getSize()); else if (const auto *VAT = dyn_cast(AT)) return CGF.getVLASize(VAT).NumElts; // Ignore pass_object_size here. It's not applicable on decayed pointers. } } QualType EltTy{Base->getType()->getPointeeOrArrayElementType(), 0}; if (llvm::Value *POS = CGF.LoadPassedObjectSize(Base, EltTy)) { IndexedType = Base->getType(); return POS; } return nullptr; } void CodeGenFunction::EmitBoundsCheck(const Expr *E, const Expr *Base, llvm::Value *Index, QualType IndexType, bool Accessed) { assert(SanOpts.has(SanitizerKind::ArrayBounds) && "should not be called unless adding bounds checks"); SanitizerScope SanScope(this); QualType IndexedType; llvm::Value *Bound = getArrayIndexingBound(*this, Base, IndexedType); if (!Bound) return; bool IndexSigned = IndexType->isSignedIntegerOrEnumerationType(); llvm::Value *IndexVal = Builder.CreateIntCast(Index, SizeTy, IndexSigned); llvm::Value *BoundVal = Builder.CreateIntCast(Bound, SizeTy, false); llvm::Constant *StaticData[] = { EmitCheckSourceLocation(E->getExprLoc()), EmitCheckTypeDescriptor(IndexedType), EmitCheckTypeDescriptor(IndexType) }; llvm::Value *Check = Accessed ? Builder.CreateICmpULT(IndexVal, BoundVal) : Builder.CreateICmpULE(IndexVal, BoundVal); EmitCheck(std::make_pair(Check, SanitizerKind::ArrayBounds), SanitizerHandler::OutOfBounds, StaticData, Index); } CodeGenFunction::ComplexPairTy CodeGenFunction:: EmitComplexPrePostIncDec(const UnaryOperator *E, LValue LV, bool isInc, bool isPre) { ComplexPairTy InVal = EmitLoadOfComplex(LV, E->getExprLoc()); llvm::Value *NextVal; if (isa(InVal.first->getType())) { uint64_t AmountVal = isInc ? 1 : -1; NextVal = llvm::ConstantInt::get(InVal.first->getType(), AmountVal, true); // Add the inc/dec to the real part. NextVal = Builder.CreateAdd(InVal.first, NextVal, isInc ? "inc" : "dec"); } else { QualType ElemTy = E->getType()->getAs()->getElementType(); llvm::APFloat FVal(getContext().getFloatTypeSemantics(ElemTy), 1); if (!isInc) FVal.changeSign(); NextVal = llvm::ConstantFP::get(getLLVMContext(), FVal); // Add the inc/dec to the real part. NextVal = Builder.CreateFAdd(InVal.first, NextVal, isInc ? "inc" : "dec"); } ComplexPairTy IncVal(NextVal, InVal.second); // Store the updated result through the lvalue. EmitStoreOfComplex(IncVal, LV, /*init*/ false); // If this is a postinc, return the value read from memory, otherwise use the // updated value. return isPre ? IncVal : InVal; } void CodeGenModule::EmitExplicitCastExprType(const ExplicitCastExpr *E, CodeGenFunction *CGF) { // Bind VLAs in the cast type. if (CGF && E->getType()->isVariablyModifiedType()) CGF->EmitVariablyModifiedType(E->getType()); if (CGDebugInfo *DI = getModuleDebugInfo()) DI->EmitExplicitCastType(E->getType()); } //===----------------------------------------------------------------------===// // LValue Expression Emission //===----------------------------------------------------------------------===// /// EmitPointerWithAlignment - Given an expression of pointer type, try to /// derive a more accurate bound on the alignment of the pointer. Address CodeGenFunction::EmitPointerWithAlignment(const Expr *E, LValueBaseInfo *BaseInfo, TBAAAccessInfo *TBAAInfo) { // We allow this with ObjC object pointers because of fragile ABIs. assert(E->getType()->isPointerType() || E->getType()->isObjCObjectPointerType()); E = E->IgnoreParens(); // Casts: if (const CastExpr *CE = dyn_cast(E)) { if (const auto *ECE = dyn_cast(CE)) CGM.EmitExplicitCastExprType(ECE, this); switch (CE->getCastKind()) { // Non-converting casts (but not C's implicit conversion from void*). case CK_BitCast: case CK_NoOp: case CK_AddressSpaceConversion: if (auto PtrTy = CE->getSubExpr()->getType()->getAs()) { if (PtrTy->getPointeeType()->isVoidType()) break; LValueBaseInfo InnerBaseInfo; TBAAAccessInfo InnerTBAAInfo; Address Addr = EmitPointerWithAlignment(CE->getSubExpr(), &InnerBaseInfo, &InnerTBAAInfo); if (BaseInfo) *BaseInfo = InnerBaseInfo; if (TBAAInfo) *TBAAInfo = InnerTBAAInfo; if (isa(CE)) { LValueBaseInfo TargetTypeBaseInfo; TBAAAccessInfo TargetTypeTBAAInfo; CharUnits Align = getNaturalPointeeTypeAlignment(E->getType(), &TargetTypeBaseInfo, &TargetTypeTBAAInfo); if (TBAAInfo) *TBAAInfo = CGM.mergeTBAAInfoForCast(*TBAAInfo, TargetTypeTBAAInfo); // If the source l-value is opaque, honor the alignment of the // casted-to type. if (InnerBaseInfo.getAlignmentSource() != AlignmentSource::Decl) { if (BaseInfo) BaseInfo->mergeForCast(TargetTypeBaseInfo); Addr = Address(Addr.getPointer(), Align); } } if (SanOpts.has(SanitizerKind::CFIUnrelatedCast) && CE->getCastKind() == CK_BitCast) { if (auto PT = E->getType()->getAs()) EmitVTablePtrCheckForCast(PT->getPointeeType(), Addr.getPointer(), /*MayBeNull=*/true, CodeGenFunction::CFITCK_UnrelatedCast, CE->getLocStart()); } return CE->getCastKind() != CK_AddressSpaceConversion ? Builder.CreateBitCast(Addr, ConvertType(E->getType())) : Builder.CreateAddrSpaceCast(Addr, ConvertType(E->getType())); } break; // Array-to-pointer decay. case CK_ArrayToPointerDecay: return EmitArrayToPointerDecay(CE->getSubExpr(), BaseInfo, TBAAInfo); // Derived-to-base conversions. case CK_UncheckedDerivedToBase: case CK_DerivedToBase: { // TODO: Support accesses to members of base classes in TBAA. For now, we // conservatively pretend that the complete object is of the base class // type. if (TBAAInfo) *TBAAInfo = CGM.getTBAAAccessInfo(E->getType()); Address Addr = EmitPointerWithAlignment(CE->getSubExpr(), BaseInfo); auto Derived = CE->getSubExpr()->getType()->getPointeeCXXRecordDecl(); return GetAddressOfBaseClass(Addr, Derived, CE->path_begin(), CE->path_end(), ShouldNullCheckClassCastValue(CE), CE->getExprLoc()); } // TODO: Is there any reason to treat base-to-derived conversions // specially? default: break; } } // Unary &. if (const UnaryOperator *UO = dyn_cast(E)) { if (UO->getOpcode() == UO_AddrOf) { LValue LV = EmitLValue(UO->getSubExpr()); if (BaseInfo) *BaseInfo = LV.getBaseInfo(); if (TBAAInfo) *TBAAInfo = LV.getTBAAInfo(); return LV.getAddress(); } } // TODO: conditional operators, comma. // Otherwise, use the alignment of the type. CharUnits Align = getNaturalPointeeTypeAlignment(E->getType(), BaseInfo, TBAAInfo); return Address(EmitScalarExpr(E), Align); } RValue CodeGenFunction::GetUndefRValue(QualType Ty) { if (Ty->isVoidType()) return RValue::get(nullptr); switch (getEvaluationKind(Ty)) { case TEK_Complex: { llvm::Type *EltTy = ConvertType(Ty->castAs()->getElementType()); llvm::Value *U = llvm::UndefValue::get(EltTy); return RValue::getComplex(std::make_pair(U, U)); } // If this is a use of an undefined aggregate type, the aggregate must have an // identifiable address. Just because the contents of the value are undefined // doesn't mean that the address can't be taken and compared. case TEK_Aggregate: { Address DestPtr = CreateMemTemp(Ty, "undef.agg.tmp"); return RValue::getAggregate(DestPtr); } case TEK_Scalar: return RValue::get(llvm::UndefValue::get(ConvertType(Ty))); } llvm_unreachable("bad evaluation kind"); } RValue CodeGenFunction::EmitUnsupportedRValue(const Expr *E, const char *Name) { ErrorUnsupported(E, Name); return GetUndefRValue(E->getType()); } LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E, const char *Name) { ErrorUnsupported(E, Name); llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType())); return MakeAddrLValue(Address(llvm::UndefValue::get(Ty), CharUnits::One()), E->getType()); } bool CodeGenFunction::IsWrappedCXXThis(const Expr *Obj) { const Expr *Base = Obj; while (!isa(Base)) { // The result of a dynamic_cast can be null. if (isa(Base)) return false; if (const auto *CE = dyn_cast(Base)) { Base = CE->getSubExpr(); } else if (const auto *PE = dyn_cast(Base)) { Base = PE->getSubExpr(); } else if (const auto *UO = dyn_cast(Base)) { if (UO->getOpcode() == UO_Extension) Base = UO->getSubExpr(); else return false; } else { return false; } } return true; } LValue CodeGenFunction::EmitCheckedLValue(const Expr *E, TypeCheckKind TCK) { LValue LV; if (SanOpts.has(SanitizerKind::ArrayBounds) && isa(E)) LV = EmitArraySubscriptExpr(cast(E), /*Accessed*/true); else LV = EmitLValue(E); if (!isa(E) && !LV.isBitField() && LV.isSimple()) { SanitizerSet SkippedChecks; if (const auto *ME = dyn_cast(E)) { bool IsBaseCXXThis = IsWrappedCXXThis(ME->getBase()); if (IsBaseCXXThis) SkippedChecks.set(SanitizerKind::Alignment, true); if (IsBaseCXXThis || isa(ME->getBase())) SkippedChecks.set(SanitizerKind::Null, true); } EmitTypeCheck(TCK, E->getExprLoc(), LV.getPointer(), E->getType(), LV.getAlignment(), SkippedChecks); } return LV; } /// EmitLValue - Emit code to compute a designator that specifies the location /// of the expression. /// /// This can return one of two things: a simple address or a bitfield reference. /// In either case, the LLVM Value* in the LValue structure is guaranteed to be /// an LLVM pointer type. /// /// If this returns a bitfield reference, nothing about the pointee type of the /// LLVM value is known: For example, it may not be a pointer to an integer. /// /// If this returns a normal address, and if the lvalue's C type is fixed size, /// this method guarantees that the returned pointer type will point to an LLVM /// type of the same size of the lvalue's type. If the lvalue has a variable /// length type, this is not possible. /// LValue CodeGenFunction::EmitLValue(const Expr *E) { ApplyDebugLocation DL(*this, E); switch (E->getStmtClass()) { default: return EmitUnsupportedLValue(E, "l-value expression"); case Expr::ObjCPropertyRefExprClass: llvm_unreachable("cannot emit a property reference directly"); case Expr::ObjCSelectorExprClass: return EmitObjCSelectorLValue(cast(E)); case Expr::ObjCIsaExprClass: return EmitObjCIsaExpr(cast(E)); case Expr::BinaryOperatorClass: return EmitBinaryOperatorLValue(cast(E)); case Expr::CompoundAssignOperatorClass: { QualType Ty = E->getType(); if (const AtomicType *AT = Ty->getAs()) Ty = AT->getValueType(); if (!Ty->isAnyComplexType()) return EmitCompoundAssignmentLValue(cast(E)); return EmitComplexCompoundAssignmentLValue(cast(E)); } case Expr::CallExprClass: case Expr::CXXMemberCallExprClass: case Expr::CXXOperatorCallExprClass: case Expr::UserDefinedLiteralClass: return EmitCallExprLValue(cast(E)); case Expr::VAArgExprClass: return EmitVAArgExprLValue(cast(E)); case Expr::DeclRefExprClass: return EmitDeclRefLValue(cast(E)); case Expr::ParenExprClass: return EmitLValue(cast(E)->getSubExpr()); case Expr::GenericSelectionExprClass: return EmitLValue(cast(E)->getResultExpr()); case Expr::PredefinedExprClass: return EmitPredefinedLValue(cast(E)); case Expr::StringLiteralClass: return EmitStringLiteralLValue(cast(E)); case Expr::ObjCEncodeExprClass: return EmitObjCEncodeExprLValue(cast(E)); case Expr::PseudoObjectExprClass: return EmitPseudoObjectLValue(cast(E)); case Expr::InitListExprClass: return EmitInitListLValue(cast(E)); case Expr::CXXTemporaryObjectExprClass: case Expr::CXXConstructExprClass: return EmitCXXConstructLValue(cast(E)); case Expr::CXXBindTemporaryExprClass: return EmitCXXBindTemporaryLValue(cast(E)); case Expr::CXXUuidofExprClass: return EmitCXXUuidofLValue(cast(E)); case Expr::LambdaExprClass: return EmitLambdaLValue(cast(E)); case Expr::ExprWithCleanupsClass: { const auto *cleanups = cast(E); enterFullExpression(cleanups); RunCleanupsScope Scope(*this); LValue LV = EmitLValue(cleanups->getSubExpr()); if (LV.isSimple()) { // Defend against branches out of gnu statement expressions surrounded by // cleanups. llvm::Value *V = LV.getPointer(); Scope.ForceCleanup({&V}); return LValue::MakeAddr(Address(V, LV.getAlignment()), LV.getType(), getContext(), LV.getBaseInfo(), LV.getTBAAInfo()); } // FIXME: Is it possible to create an ExprWithCleanups that produces a // bitfield lvalue or some other non-simple lvalue? return LV; } case Expr::CXXDefaultArgExprClass: return EmitLValue(cast(E)->getExpr()); case Expr::CXXDefaultInitExprClass: { CXXDefaultInitExprScope Scope(*this); return EmitLValue(cast(E)->getExpr()); } case Expr::CXXTypeidExprClass: return EmitCXXTypeidLValue(cast(E)); case Expr::ObjCMessageExprClass: return EmitObjCMessageExprLValue(cast(E)); case Expr::ObjCIvarRefExprClass: return EmitObjCIvarRefLValue(cast(E)); case Expr::StmtExprClass: return EmitStmtExprLValue(cast(E)); case Expr::UnaryOperatorClass: return EmitUnaryOpLValue(cast(E)); case Expr::ArraySubscriptExprClass: return EmitArraySubscriptExpr(cast(E)); case Expr::OMPArraySectionExprClass: return EmitOMPArraySectionExpr(cast(E)); case Expr::ExtVectorElementExprClass: return EmitExtVectorElementExpr(cast(E)); case Expr::MemberExprClass: return EmitMemberExpr(cast(E)); case Expr::CompoundLiteralExprClass: return EmitCompoundLiteralLValue(cast(E)); case Expr::ConditionalOperatorClass: return EmitConditionalOperatorLValue(cast(E)); case Expr::BinaryConditionalOperatorClass: return EmitConditionalOperatorLValue(cast(E)); case Expr::ChooseExprClass: return EmitLValue(cast(E)->getChosenSubExpr()); case Expr::OpaqueValueExprClass: return EmitOpaqueValueLValue(cast(E)); case Expr::SubstNonTypeTemplateParmExprClass: return EmitLValue(cast(E)->getReplacement()); case Expr::ImplicitCastExprClass: case Expr::CStyleCastExprClass: case Expr::CXXFunctionalCastExprClass: case Expr::CXXStaticCastExprClass: case Expr::CXXDynamicCastExprClass: case Expr::CXXReinterpretCastExprClass: case Expr::CXXConstCastExprClass: case Expr::ObjCBridgedCastExprClass: return EmitCastLValue(cast(E)); case Expr::MaterializeTemporaryExprClass: return EmitMaterializeTemporaryExpr(cast(E)); case Expr::CoawaitExprClass: return EmitCoawaitLValue(cast(E)); case Expr::CoyieldExprClass: return EmitCoyieldLValue(cast(E)); } } /// Given an object of the given canonical type, can we safely copy a /// value out of it based on its initializer? static bool isConstantEmittableObjectType(QualType type) { assert(type.isCanonical()); assert(!type->isReferenceType()); // Must be const-qualified but non-volatile. Qualifiers qs = type.getLocalQualifiers(); if (!qs.hasConst() || qs.hasVolatile()) return false; // Otherwise, all object types satisfy this except C++ classes with // mutable subobjects or non-trivial copy/destroy behavior. if (const auto *RT = dyn_cast(type)) if (const auto *RD = dyn_cast(RT->getDecl())) if (RD->hasMutableFields() || !RD->isTrivial()) return false; return true; } /// Can we constant-emit a load of a reference to a variable of the /// given type? This is different from predicates like /// Decl::isUsableInConstantExpressions because we do want it to apply /// in situations that don't necessarily satisfy the language's rules /// for this (e.g. C++'s ODR-use rules). For example, we want to able /// to do this with const float variables even if those variables /// aren't marked 'constexpr'. enum ConstantEmissionKind { CEK_None, CEK_AsReferenceOnly, CEK_AsValueOrReference, CEK_AsValueOnly }; static ConstantEmissionKind checkVarTypeForConstantEmission(QualType type) { type = type.getCanonicalType(); if (const auto *ref = dyn_cast(type)) { if (isConstantEmittableObjectType(ref->getPointeeType())) return CEK_AsValueOrReference; return CEK_AsReferenceOnly; } if (isConstantEmittableObjectType(type)) return CEK_AsValueOnly; return CEK_None; } /// Try to emit a reference to the given value without producing it as /// an l-value. This is actually more than an optimization: we can't /// produce an l-value for variables that we never actually captured /// in a block or lambda, which means const int variables or constexpr /// literals or similar. CodeGenFunction::ConstantEmission CodeGenFunction::tryEmitAsConstant(DeclRefExpr *refExpr) { ValueDecl *value = refExpr->getDecl(); // The value needs to be an enum constant or a constant variable. ConstantEmissionKind CEK; if (isa(value)) { CEK = CEK_None; } else if (auto *var = dyn_cast(value)) { CEK = checkVarTypeForConstantEmission(var->getType()); } else if (isa(value)) { CEK = CEK_AsValueOnly; } else { CEK = CEK_None; } if (CEK == CEK_None) return ConstantEmission(); Expr::EvalResult result; bool resultIsReference; QualType resultType; // It's best to evaluate all the way as an r-value if that's permitted. if (CEK != CEK_AsReferenceOnly && refExpr->EvaluateAsRValue(result, getContext())) { resultIsReference = false; resultType = refExpr->getType(); // Otherwise, try to evaluate as an l-value. } else if (CEK != CEK_AsValueOnly && refExpr->EvaluateAsLValue(result, getContext())) { resultIsReference = true; resultType = value->getType(); // Failure. } else { return ConstantEmission(); } // In any case, if the initializer has side-effects, abandon ship. if (result.HasSideEffects) return ConstantEmission(); // Emit as a constant. auto C = ConstantEmitter(*this).emitAbstract(refExpr->getLocation(), result.Val, resultType); // Make sure we emit a debug reference to the global variable. // This should probably fire even for if (isa(value)) { if (!getContext().DeclMustBeEmitted(cast(value))) EmitDeclRefExprDbgValue(refExpr, result.Val); } else { assert(isa(value)); EmitDeclRefExprDbgValue(refExpr, result.Val); } // If we emitted a reference constant, we need to dereference that. if (resultIsReference) return ConstantEmission::forReference(C); return ConstantEmission::forValue(C); } static DeclRefExpr *tryToConvertMemberExprToDeclRefExpr(CodeGenFunction &CGF, const MemberExpr *ME) { if (auto *VD = dyn_cast(ME->getMemberDecl())) { // Try to emit static variable member expressions as DREs. return DeclRefExpr::Create( CGF.getContext(), NestedNameSpecifierLoc(), SourceLocation(), VD, /*RefersToEnclosingVariableOrCapture=*/false, ME->getExprLoc(), ME->getType(), ME->getValueKind()); } return nullptr; } CodeGenFunction::ConstantEmission CodeGenFunction::tryEmitAsConstant(const MemberExpr *ME) { if (DeclRefExpr *DRE = tryToConvertMemberExprToDeclRefExpr(*this, ME)) return tryEmitAsConstant(DRE); return ConstantEmission(); } llvm::Value *CodeGenFunction::EmitLoadOfScalar(LValue lvalue, SourceLocation Loc) { return EmitLoadOfScalar(lvalue.getAddress(), lvalue.isVolatile(), lvalue.getType(), Loc, lvalue.getBaseInfo(), lvalue.getTBAAInfo(), lvalue.isNontemporal()); } static bool hasBooleanRepresentation(QualType Ty) { if (Ty->isBooleanType()) return true; if (const EnumType *ET = Ty->getAs()) return ET->getDecl()->getIntegerType()->isBooleanType(); if (const AtomicType *AT = Ty->getAs()) return hasBooleanRepresentation(AT->getValueType()); return false; } static bool getRangeForType(CodeGenFunction &CGF, QualType Ty, llvm::APInt &Min, llvm::APInt &End, bool StrictEnums, bool IsBool) { const EnumType *ET = Ty->getAs(); bool IsRegularCPlusPlusEnum = CGF.getLangOpts().CPlusPlus && StrictEnums && ET && !ET->getDecl()->isFixed(); if (!IsBool && !IsRegularCPlusPlusEnum) return false; if (IsBool) { Min = llvm::APInt(CGF.getContext().getTypeSize(Ty), 0); End = llvm::APInt(CGF.getContext().getTypeSize(Ty), 2); } else { const EnumDecl *ED = ET->getDecl(); llvm::Type *LTy = CGF.ConvertTypeForMem(ED->getIntegerType()); unsigned Bitwidth = LTy->getScalarSizeInBits(); unsigned NumNegativeBits = ED->getNumNegativeBits(); unsigned NumPositiveBits = ED->getNumPositiveBits(); if (NumNegativeBits) { unsigned NumBits = std::max(NumNegativeBits, NumPositiveBits + 1); assert(NumBits <= Bitwidth); End = llvm::APInt(Bitwidth, 1) << (NumBits - 1); Min = -End; } else { assert(NumPositiveBits <= Bitwidth); End = llvm::APInt(Bitwidth, 1) << NumPositiveBits; Min = llvm::APInt(Bitwidth, 0); } } return true; } llvm::MDNode *CodeGenFunction::getRangeForLoadFromType(QualType Ty) { llvm::APInt Min, End; if (!getRangeForType(*this, Ty, Min, End, CGM.getCodeGenOpts().StrictEnums, hasBooleanRepresentation(Ty))) return nullptr; llvm::MDBuilder MDHelper(getLLVMContext()); return MDHelper.createRange(Min, End); } bool CodeGenFunction::EmitScalarRangeCheck(llvm::Value *Value, QualType Ty, SourceLocation Loc) { bool HasBoolCheck = SanOpts.has(SanitizerKind::Bool); bool HasEnumCheck = SanOpts.has(SanitizerKind::Enum); if (!HasBoolCheck && !HasEnumCheck) return false; bool IsBool = hasBooleanRepresentation(Ty) || NSAPI(CGM.getContext()).isObjCBOOLType(Ty); bool NeedsBoolCheck = HasBoolCheck && IsBool; bool NeedsEnumCheck = HasEnumCheck && Ty->getAs(); if (!NeedsBoolCheck && !NeedsEnumCheck) return false; // Single-bit booleans don't need to be checked. Special-case this to avoid // a bit width mismatch when handling bitfield values. This is handled by // EmitFromMemory for the non-bitfield case. if (IsBool && cast(Value->getType())->getBitWidth() == 1) return false; llvm::APInt Min, End; if (!getRangeForType(*this, Ty, Min, End, /*StrictEnums=*/true, IsBool)) return true; auto &Ctx = getLLVMContext(); SanitizerScope SanScope(this); llvm::Value *Check; --End; if (!Min) { Check = Builder.CreateICmpULE(Value, llvm::ConstantInt::get(Ctx, End)); } else { llvm::Value *Upper = Builder.CreateICmpSLE(Value, llvm::ConstantInt::get(Ctx, End)); llvm::Value *Lower = Builder.CreateICmpSGE(Value, llvm::ConstantInt::get(Ctx, Min)); Check = Builder.CreateAnd(Upper, Lower); } llvm::Constant *StaticArgs[] = {EmitCheckSourceLocation(Loc), EmitCheckTypeDescriptor(Ty)}; SanitizerMask Kind = NeedsEnumCheck ? SanitizerKind::Enum : SanitizerKind::Bool; EmitCheck(std::make_pair(Check, Kind), SanitizerHandler::LoadInvalidValue, StaticArgs, EmitCheckValue(Value)); return true; } llvm::Value *CodeGenFunction::EmitLoadOfScalar(Address Addr, bool Volatile, QualType Ty, SourceLocation Loc, LValueBaseInfo BaseInfo, TBAAAccessInfo TBAAInfo, bool isNontemporal) { if (!CGM.getCodeGenOpts().PreserveVec3Type) { // For better performance, handle vector loads differently. if (Ty->isVectorType()) { const llvm::Type *EltTy = Addr.getElementType(); const auto *VTy = cast(EltTy); // Handle vectors of size 3 like size 4 for better performance. if (VTy->getNumElements() == 3) { // Bitcast to vec4 type. llvm::VectorType *vec4Ty = llvm::VectorType::get(VTy->getElementType(), 4); Address Cast = Builder.CreateElementBitCast(Addr, vec4Ty, "castToVec4"); // Now load value. llvm::Value *V = Builder.CreateLoad(Cast, Volatile, "loadVec4"); // Shuffle vector to get vec3. V = Builder.CreateShuffleVector(V, llvm::UndefValue::get(vec4Ty), {0, 1, 2}, "extractVec"); return EmitFromMemory(V, Ty); } } } // Atomic operations have to be done on integral types. LValue AtomicLValue = LValue::MakeAddr(Addr, Ty, getContext(), BaseInfo, TBAAInfo); if (Ty->isAtomicType() || LValueIsSuitableForInlineAtomic(AtomicLValue)) { return EmitAtomicLoad(AtomicLValue, Loc).getScalarVal(); } llvm::LoadInst *Load = Builder.CreateLoad(Addr, Volatile); if (isNontemporal) { llvm::MDNode *Node = llvm::MDNode::get( Load->getContext(), llvm::ConstantAsMetadata::get(Builder.getInt32(1))); Load->setMetadata(CGM.getModule().getMDKindID("nontemporal"), Node); } CGM.DecorateInstructionWithTBAA(Load, TBAAInfo); if (EmitScalarRangeCheck(Load, Ty, Loc)) { // In order to prevent the optimizer from throwing away the check, don't // attach range metadata to the load. } else if (CGM.getCodeGenOpts().OptimizationLevel > 0) if (llvm::MDNode *RangeInfo = getRangeForLoadFromType(Ty)) Load->setMetadata(llvm::LLVMContext::MD_range, RangeInfo); return EmitFromMemory(Load, Ty); } llvm::Value *CodeGenFunction::EmitToMemory(llvm::Value *Value, QualType Ty) { // Bool has a different representation in memory than in registers. if (hasBooleanRepresentation(Ty)) { // This should really always be an i1, but sometimes it's already // an i8, and it's awkward to track those cases down. if (Value->getType()->isIntegerTy(1)) return Builder.CreateZExt(Value, ConvertTypeForMem(Ty), "frombool"); assert(Value->getType()->isIntegerTy(getContext().getTypeSize(Ty)) && "wrong value rep of bool"); } return Value; } llvm::Value *CodeGenFunction::EmitFromMemory(llvm::Value *Value, QualType Ty) { // Bool has a different representation in memory than in registers. if (hasBooleanRepresentation(Ty)) { assert(Value->getType()->isIntegerTy(getContext().getTypeSize(Ty)) && "wrong value rep of bool"); return Builder.CreateTrunc(Value, Builder.getInt1Ty(), "tobool"); } return Value; } void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, Address Addr, bool Volatile, QualType Ty, LValueBaseInfo BaseInfo, TBAAAccessInfo TBAAInfo, bool isInit, bool isNontemporal) { if (!CGM.getCodeGenOpts().PreserveVec3Type) { // Handle vectors differently to get better performance. if (Ty->isVectorType()) { llvm::Type *SrcTy = Value->getType(); auto *VecTy = dyn_cast(SrcTy); // Handle vec3 special. if (VecTy && VecTy->getNumElements() == 3) { // Our source is a vec3, do a shuffle vector to make it a vec4. llvm::Constant *Mask[] = {Builder.getInt32(0), Builder.getInt32(1), Builder.getInt32(2), llvm::UndefValue::get(Builder.getInt32Ty())}; llvm::Value *MaskV = llvm::ConstantVector::get(Mask); Value = Builder.CreateShuffleVector(Value, llvm::UndefValue::get(VecTy), MaskV, "extractVec"); SrcTy = llvm::VectorType::get(VecTy->getElementType(), 4); } if (Addr.getElementType() != SrcTy) { Addr = Builder.CreateElementBitCast(Addr, SrcTy, "storetmp"); } } } Value = EmitToMemory(Value, Ty); LValue AtomicLValue = LValue::MakeAddr(Addr, Ty, getContext(), BaseInfo, TBAAInfo); if (Ty->isAtomicType() || (!isInit && LValueIsSuitableForInlineAtomic(AtomicLValue))) { EmitAtomicStore(RValue::get(Value), AtomicLValue, isInit); return; } llvm::StoreInst *Store = Builder.CreateStore(Value, Addr, Volatile); if (isNontemporal) { llvm::MDNode *Node = llvm::MDNode::get(Store->getContext(), llvm::ConstantAsMetadata::get(Builder.getInt32(1))); Store->setMetadata(CGM.getModule().getMDKindID("nontemporal"), Node); } CGM.DecorateInstructionWithTBAA(Store, TBAAInfo); } void CodeGenFunction::EmitStoreOfScalar(llvm::Value *value, LValue lvalue, bool isInit) { EmitStoreOfScalar(value, lvalue.getAddress(), lvalue.isVolatile(), lvalue.getType(), lvalue.getBaseInfo(), lvalue.getTBAAInfo(), isInit, lvalue.isNontemporal()); } /// EmitLoadOfLValue - Given an expression that represents a value lvalue, this /// method emits the address of the lvalue, then loads the result as an rvalue, /// returning the rvalue. RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, SourceLocation Loc) { if (LV.isObjCWeak()) { // load of a __weak object. Address AddrWeakObj = LV.getAddress(); return RValue::get(CGM.getObjCRuntime().EmitObjCWeakRead(*this, AddrWeakObj)); } if (LV.getQuals().getObjCLifetime() == Qualifiers::OCL_Weak) { // In MRC mode, we do a load+autorelease. if (!getLangOpts().ObjCAutoRefCount) { return RValue::get(EmitARCLoadWeak(LV.getAddress())); } // In ARC mode, we load retained and then consume the value. llvm::Value *Object = EmitARCLoadWeakRetained(LV.getAddress()); Object = EmitObjCConsumeObject(LV.getType(), Object); return RValue::get(Object); } if (LV.isSimple()) { assert(!LV.getType()->isFunctionType()); // Everything needs a load. return RValue::get(EmitLoadOfScalar(LV, Loc)); } if (LV.isVectorElt()) { llvm::LoadInst *Load = Builder.CreateLoad(LV.getVectorAddress(), LV.isVolatileQualified()); return RValue::get(Builder.CreateExtractElement(Load, LV.getVectorIdx(), "vecext")); } // If this is a reference to a subset of the elements of a vector, either // shuffle the input or extract/insert them as appropriate. if (LV.isExtVectorElt()) return EmitLoadOfExtVectorElementLValue(LV); // Global Register variables always invoke intrinsics if (LV.isGlobalReg()) return EmitLoadOfGlobalRegLValue(LV); assert(LV.isBitField() && "Unknown LValue type!"); return EmitLoadOfBitfieldLValue(LV, Loc); } RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV, SourceLocation Loc) { const CGBitFieldInfo &Info = LV.getBitFieldInfo(); // Get the output type. llvm::Type *ResLTy = ConvertType(LV.getType()); Address Ptr = LV.getBitFieldAddress(); llvm::Value *Val = Builder.CreateLoad(Ptr, LV.isVolatileQualified(), "bf.load"); if (Info.IsSigned) { assert(static_cast(Info.Offset + Info.Size) <= Info.StorageSize); unsigned HighBits = Info.StorageSize - Info.Offset - Info.Size; if (HighBits) Val = Builder.CreateShl(Val, HighBits, "bf.shl"); if (Info.Offset + HighBits) Val = Builder.CreateAShr(Val, Info.Offset + HighBits, "bf.ashr"); } else { if (Info.Offset) Val = Builder.CreateLShr(Val, Info.Offset, "bf.lshr"); if (static_cast(Info.Offset) + Info.Size < Info.StorageSize) Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(Info.StorageSize, Info.Size), "bf.clear"); } Val = Builder.CreateIntCast(Val, ResLTy, Info.IsSigned, "bf.cast"); EmitScalarRangeCheck(Val, LV.getType(), Loc); return RValue::get(Val); } // If this is a reference to a subset of the elements of a vector, create an // appropriate shufflevector. RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV) { llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddress(), LV.isVolatileQualified()); const llvm::Constant *Elts = LV.getExtVectorElts(); // If the result of the expression is a non-vector type, we must be extracting // a single element. Just codegen as an extractelement. const VectorType *ExprVT = LV.getType()->getAs(); if (!ExprVT) { unsigned InIdx = getAccessedFieldNo(0, Elts); llvm::Value *Elt = llvm::ConstantInt::get(SizeTy, InIdx); return RValue::get(Builder.CreateExtractElement(Vec, Elt)); } // Always use shuffle vector to try to retain the original program structure unsigned NumResultElts = ExprVT->getNumElements(); SmallVector Mask; for (unsigned i = 0; i != NumResultElts; ++i) Mask.push_back(Builder.getInt32(getAccessedFieldNo(i, Elts))); llvm::Value *MaskV = llvm::ConstantVector::get(Mask); Vec = Builder.CreateShuffleVector(Vec, llvm::UndefValue::get(Vec->getType()), MaskV); return RValue::get(Vec); } /// Generates lvalue for partial ext_vector access. Address CodeGenFunction::EmitExtVectorElementLValue(LValue LV) { Address VectorAddress = LV.getExtVectorAddress(); const VectorType *ExprVT = LV.getType()->getAs(); QualType EQT = ExprVT->getElementType(); llvm::Type *VectorElementTy = CGM.getTypes().ConvertType(EQT); Address CastToPointerElement = Builder.CreateElementBitCast(VectorAddress, VectorElementTy, "conv.ptr.element"); const llvm::Constant *Elts = LV.getExtVectorElts(); unsigned ix = getAccessedFieldNo(0, Elts); Address VectorBasePtrPlusIx = Builder.CreateConstInBoundsGEP(CastToPointerElement, ix, getContext().getTypeSizeInChars(EQT), "vector.elt"); return VectorBasePtrPlusIx; } /// Load of global gamed gegisters are always calls to intrinsics. RValue CodeGenFunction::EmitLoadOfGlobalRegLValue(LValue LV) { assert((LV.getType()->isIntegerType() || LV.getType()->isPointerType()) && "Bad type for register variable"); llvm::MDNode *RegName = cast( cast(LV.getGlobalReg())->getMetadata()); // We accept integer and pointer types only llvm::Type *OrigTy = CGM.getTypes().ConvertType(LV.getType()); llvm::Type *Ty = OrigTy; if (OrigTy->isPointerTy()) Ty = CGM.getTypes().getDataLayout().getIntPtrType(OrigTy); llvm::Type *Types[] = { Ty }; llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::read_register, Types); llvm::Value *Call = Builder.CreateCall( F, llvm::MetadataAsValue::get(Ty->getContext(), RegName)); if (OrigTy->isPointerTy()) Call = Builder.CreateIntToPtr(Call, OrigTy); return RValue::get(Call); } /// EmitStoreThroughLValue - Store the specified rvalue into the specified /// lvalue, where both are guaranteed to the have the same type, and that type /// is 'Ty'. void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst, bool isInit) { if (!Dst.isSimple()) { if (Dst.isVectorElt()) { // Read/modify/write the vector, inserting the new element. llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddress(), Dst.isVolatileQualified()); Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(), Dst.getVectorIdx(), "vecins"); Builder.CreateStore(Vec, Dst.getVectorAddress(), Dst.isVolatileQualified()); return; } // If this is an update of extended vector elements, insert them as // appropriate. if (Dst.isExtVectorElt()) return EmitStoreThroughExtVectorComponentLValue(Src, Dst); if (Dst.isGlobalReg()) return EmitStoreThroughGlobalRegLValue(Src, Dst); assert(Dst.isBitField() && "Unknown LValue type"); return EmitStoreThroughBitfieldLValue(Src, Dst); } // There's special magic for assigning into an ARC-qualified l-value. if (Qualifiers::ObjCLifetime Lifetime = Dst.getQuals().getObjCLifetime()) { switch (Lifetime) { case Qualifiers::OCL_None: llvm_unreachable("present but none"); case Qualifiers::OCL_ExplicitNone: // nothing special break; case Qualifiers::OCL_Strong: if (isInit) { Src = RValue::get(EmitARCRetain(Dst.getType(), Src.getScalarVal())); break; } EmitARCStoreStrong(Dst, Src.getScalarVal(), /*ignore*/ true); return; case Qualifiers::OCL_Weak: if (isInit) // Initialize and then skip the primitive store. EmitARCInitWeak(Dst.getAddress(), Src.getScalarVal()); else EmitARCStoreWeak(Dst.getAddress(), Src.getScalarVal(), /*ignore*/ true); return; case Qualifiers::OCL_Autoreleasing: Src = RValue::get(EmitObjCExtendObjectLifetime(Dst.getType(), Src.getScalarVal())); // fall into the normal path break; } } if (Dst.isObjCWeak() && !Dst.isNonGC()) { // load of a __weak object. Address LvalueDst = Dst.getAddress(); llvm::Value *src = Src.getScalarVal(); CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst); return; } if (Dst.isObjCStrong() && !Dst.isNonGC()) { // load of a __strong object. Address LvalueDst = Dst.getAddress(); llvm::Value *src = Src.getScalarVal(); if (Dst.isObjCIvar()) { assert(Dst.getBaseIvarExp() && "BaseIvarExp is NULL"); llvm::Type *ResultType = IntPtrTy; Address dst = EmitPointerWithAlignment(Dst.getBaseIvarExp()); llvm::Value *RHS = dst.getPointer(); RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast"); llvm::Value *LHS = Builder.CreatePtrToInt(LvalueDst.getPointer(), ResultType, "sub.ptr.lhs.cast"); llvm::Value *BytesBetween = Builder.CreateSub(LHS, RHS, "ivar.offset"); CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, dst, BytesBetween); } else if (Dst.isGlobalObjCRef()) { CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst, Dst.isThreadLocalRef()); } else CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst); return; } assert(Src.isScalar() && "Can't emit an agg store with this method"); EmitStoreOfScalar(Src.getScalarVal(), Dst, isInit); } void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst, llvm::Value **Result) { const CGBitFieldInfo &Info = Dst.getBitFieldInfo(); llvm::Type *ResLTy = ConvertTypeForMem(Dst.getType()); Address Ptr = Dst.getBitFieldAddress(); // Get the source value, truncated to the width of the bit-field. llvm::Value *SrcVal = Src.getScalarVal(); // Cast the source to the storage type and shift it into place. SrcVal = Builder.CreateIntCast(SrcVal, Ptr.getElementType(), /*IsSigned=*/false); llvm::Value *MaskedVal = SrcVal; // See if there are other bits in the bitfield's storage we'll need to load // and mask together with source before storing. if (Info.StorageSize != Info.Size) { assert(Info.StorageSize > Info.Size && "Invalid bitfield size."); llvm::Value *Val = Builder.CreateLoad(Ptr, Dst.isVolatileQualified(), "bf.load"); // Mask the source value as needed. if (!hasBooleanRepresentation(Dst.getType())) SrcVal = Builder.CreateAnd(SrcVal, llvm::APInt::getLowBitsSet(Info.StorageSize, Info.Size), "bf.value"); MaskedVal = SrcVal; if (Info.Offset) SrcVal = Builder.CreateShl(SrcVal, Info.Offset, "bf.shl"); // Mask out the original value. Val = Builder.CreateAnd(Val, ~llvm::APInt::getBitsSet(Info.StorageSize, Info.Offset, Info.Offset + Info.Size), "bf.clear"); // Or together the unchanged values and the source value. SrcVal = Builder.CreateOr(Val, SrcVal, "bf.set"); } else { assert(Info.Offset == 0); } // Write the new value back out. Builder.CreateStore(SrcVal, Ptr, Dst.isVolatileQualified()); // Return the new value of the bit-field, if requested. if (Result) { llvm::Value *ResultVal = MaskedVal; // Sign extend the value if needed. if (Info.IsSigned) { assert(Info.Size <= Info.StorageSize); unsigned HighBits = Info.StorageSize - Info.Size; if (HighBits) { ResultVal = Builder.CreateShl(ResultVal, HighBits, "bf.result.shl"); ResultVal = Builder.CreateAShr(ResultVal, HighBits, "bf.result.ashr"); } } ResultVal = Builder.CreateIntCast(ResultVal, ResLTy, Info.IsSigned, "bf.result.cast"); *Result = EmitFromMemory(ResultVal, Dst.getType()); } } void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src, LValue Dst) { // This access turns into a read/modify/write of the vector. Load the input // value now. llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddress(), Dst.isVolatileQualified()); const llvm::Constant *Elts = Dst.getExtVectorElts(); llvm::Value *SrcVal = Src.getScalarVal(); if (const VectorType *VTy = Dst.getType()->getAs()) { unsigned NumSrcElts = VTy->getNumElements(); unsigned NumDstElts = Vec->getType()->getVectorNumElements(); if (NumDstElts == NumSrcElts) { // Use shuffle vector is the src and destination are the same number of // elements and restore the vector mask since it is on the side it will be // stored. SmallVector Mask(NumDstElts); for (unsigned i = 0; i != NumSrcElts; ++i) Mask[getAccessedFieldNo(i, Elts)] = Builder.getInt32(i); llvm::Value *MaskV = llvm::ConstantVector::get(Mask); Vec = Builder.CreateShuffleVector(SrcVal, llvm::UndefValue::get(Vec->getType()), MaskV); } else if (NumDstElts > NumSrcElts) { // Extended the source vector to the same length and then shuffle it // into the destination. // FIXME: since we're shuffling with undef, can we just use the indices // into that? This could be simpler. SmallVector ExtMask; for (unsigned i = 0; i != NumSrcElts; ++i) ExtMask.push_back(Builder.getInt32(i)); ExtMask.resize(NumDstElts, llvm::UndefValue::get(Int32Ty)); llvm::Value *ExtMaskV = llvm::ConstantVector::get(ExtMask); llvm::Value *ExtSrcVal = Builder.CreateShuffleVector(SrcVal, llvm::UndefValue::get(SrcVal->getType()), ExtMaskV); // build identity SmallVector Mask; for (unsigned i = 0; i != NumDstElts; ++i) Mask.push_back(Builder.getInt32(i)); // When the vector size is odd and .odd or .hi is used, the last element // of the Elts constant array will be one past the size of the vector. // Ignore the last element here, if it is greater than the mask size. if (getAccessedFieldNo(NumSrcElts - 1, Elts) == Mask.size()) NumSrcElts--; // modify when what gets shuffled in for (unsigned i = 0; i != NumSrcElts; ++i) Mask[getAccessedFieldNo(i, Elts)] = Builder.getInt32(i+NumDstElts); llvm::Value *MaskV = llvm::ConstantVector::get(Mask); Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV); } else { // We should never shorten the vector llvm_unreachable("unexpected shorten vector length"); } } else { // If the Src is a scalar (not a vector) it must be updating one element. unsigned InIdx = getAccessedFieldNo(0, Elts); llvm::Value *Elt = llvm::ConstantInt::get(SizeTy, InIdx); Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt); } Builder.CreateStore(Vec, Dst.getExtVectorAddress(), Dst.isVolatileQualified()); } /// Store of global named registers are always calls to intrinsics. void CodeGenFunction::EmitStoreThroughGlobalRegLValue(RValue Src, LValue Dst) { assert((Dst.getType()->isIntegerType() || Dst.getType()->isPointerType()) && "Bad type for register variable"); llvm::MDNode *RegName = cast( cast(Dst.getGlobalReg())->getMetadata()); assert(RegName && "Register LValue is not metadata"); // We accept integer and pointer types only llvm::Type *OrigTy = CGM.getTypes().ConvertType(Dst.getType()); llvm::Type *Ty = OrigTy; if (OrigTy->isPointerTy()) Ty = CGM.getTypes().getDataLayout().getIntPtrType(OrigTy); llvm::Type *Types[] = { Ty }; llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::write_register, Types); llvm::Value *Value = Src.getScalarVal(); if (OrigTy->isPointerTy()) Value = Builder.CreatePtrToInt(Value, Ty); Builder.CreateCall( F, {llvm::MetadataAsValue::get(Ty->getContext(), RegName), Value}); } // setObjCGCLValueClass - sets class of the lvalue for the purpose of // generating write-barries API. It is currently a global, ivar, // or neither. static void setObjCGCLValueClass(const ASTContext &Ctx, const Expr *E, LValue &LV, bool IsMemberAccess=false) { if (Ctx.getLangOpts().getGC() == LangOptions::NonGC) return; if (isa(E)) { QualType ExpTy = E->getType(); if (IsMemberAccess && ExpTy->isPointerType()) { // If ivar is a structure pointer, assigning to field of // this struct follows gcc's behavior and makes it a non-ivar // writer-barrier conservatively. ExpTy = ExpTy->getAs()->getPointeeType(); if (ExpTy->isRecordType()) { LV.setObjCIvar(false); return; } } LV.setObjCIvar(true); auto *Exp = cast(const_cast(E)); LV.setBaseIvarExp(Exp->getBase()); LV.setObjCArray(E->getType()->isArrayType()); return; } if (const auto *Exp = dyn_cast(E)) { if (const auto *VD = dyn_cast(Exp->getDecl())) { if (VD->hasGlobalStorage()) { LV.setGlobalObjCRef(true); LV.setThreadLocalRef(VD->getTLSKind() != VarDecl::TLS_None); } } LV.setObjCArray(E->getType()->isArrayType()); return; } if (const auto *Exp = dyn_cast(E)) { setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess); return; } if (const auto *Exp = dyn_cast(E)) { setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess); if (LV.isObjCIvar()) { // If cast is to a structure pointer, follow gcc's behavior and make it // a non-ivar write-barrier. QualType ExpTy = E->getType(); if (ExpTy->isPointerType()) ExpTy = ExpTy->getAs()->getPointeeType(); if (ExpTy->isRecordType()) LV.setObjCIvar(false); } return; } if (const auto *Exp = dyn_cast(E)) { setObjCGCLValueClass(Ctx, Exp->getResultExpr(), LV); return; } if (const auto *Exp = dyn_cast(E)) { setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess); return; } if (const auto *Exp = dyn_cast(E)) { setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess); return; } if (const auto *Exp = dyn_cast(E)) { setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess); return; } if (const auto *Exp = dyn_cast(E)) { setObjCGCLValueClass(Ctx, Exp->getBase(), LV); if (LV.isObjCIvar() && !LV.isObjCArray()) // Using array syntax to assigning to what an ivar points to is not // same as assigning to the ivar itself. {id *Names;} Names[i] = 0; LV.setObjCIvar(false); else if (LV.isGlobalObjCRef() && !LV.isObjCArray()) // Using array syntax to assigning to what global points to is not // same as assigning to the global itself. {id *G;} G[i] = 0; LV.setGlobalObjCRef(false); return; } if (const auto *Exp = dyn_cast(E)) { setObjCGCLValueClass(Ctx, Exp->getBase(), LV, true); // We don't know if member is an 'ivar', but this flag is looked at // only in the context of LV.isObjCIvar(). LV.setObjCArray(E->getType()->isArrayType()); return; } } static llvm::Value * EmitBitCastOfLValueToProperType(CodeGenFunction &CGF, llvm::Value *V, llvm::Type *IRType, StringRef Name = StringRef()) { unsigned AS = cast(V->getType())->getAddressSpace(); return CGF.Builder.CreateBitCast(V, IRType->getPointerTo(AS), Name); } static LValue EmitThreadPrivateVarDeclLValue( CodeGenFunction &CGF, const VarDecl *VD, QualType T, Address Addr, llvm::Type *RealVarTy, SourceLocation Loc) { Addr = CGF.CGM.getOpenMPRuntime().getAddrOfThreadPrivate(CGF, VD, Addr, Loc); Addr = CGF.Builder.CreateElementBitCast(Addr, RealVarTy); return CGF.MakeAddrLValue(Addr, T, AlignmentSource::Decl); } static Address emitDeclTargetLinkVarDeclLValue(CodeGenFunction &CGF, const VarDecl *VD, QualType T) { for (const auto *D : VD->redecls()) { if (!VD->hasAttrs()) continue; if (const auto *Attr = D->getAttr()) if (Attr->getMapType() == OMPDeclareTargetDeclAttr::MT_Link) { QualType PtrTy = CGF.getContext().getPointerType(VD->getType()); Address Addr = CGF.CGM.getOpenMPRuntime().getAddrOfDeclareTargetLink(VD); return CGF.EmitLoadOfPointer(Addr, PtrTy->castAs()); } } return Address::invalid(); } Address CodeGenFunction::EmitLoadOfReference(LValue RefLVal, LValueBaseInfo *PointeeBaseInfo, TBAAAccessInfo *PointeeTBAAInfo) { llvm::LoadInst *Load = Builder.CreateLoad(RefLVal.getAddress(), RefLVal.isVolatile()); CGM.DecorateInstructionWithTBAA(Load, RefLVal.getTBAAInfo()); CharUnits Align = getNaturalTypeAlignment(RefLVal.getType()->getPointeeType(), PointeeBaseInfo, PointeeTBAAInfo, /* forPointeeType= */ true); return Address(Load, Align); } LValue CodeGenFunction::EmitLoadOfReferenceLValue(LValue RefLVal) { LValueBaseInfo PointeeBaseInfo; TBAAAccessInfo PointeeTBAAInfo; Address PointeeAddr = EmitLoadOfReference(RefLVal, &PointeeBaseInfo, &PointeeTBAAInfo); return MakeAddrLValue(PointeeAddr, RefLVal.getType()->getPointeeType(), PointeeBaseInfo, PointeeTBAAInfo); } Address CodeGenFunction::EmitLoadOfPointer(Address Ptr, const PointerType *PtrTy, LValueBaseInfo *BaseInfo, TBAAAccessInfo *TBAAInfo) { llvm::Value *Addr = Builder.CreateLoad(Ptr); return Address(Addr, getNaturalTypeAlignment(PtrTy->getPointeeType(), BaseInfo, TBAAInfo, /*forPointeeType=*/true)); } LValue CodeGenFunction::EmitLoadOfPointerLValue(Address PtrAddr, const PointerType *PtrTy) { LValueBaseInfo BaseInfo; TBAAAccessInfo TBAAInfo; Address Addr = EmitLoadOfPointer(PtrAddr, PtrTy, &BaseInfo, &TBAAInfo); return MakeAddrLValue(Addr, PtrTy->getPointeeType(), BaseInfo, TBAAInfo); } static LValue EmitGlobalVarDeclLValue(CodeGenFunction &CGF, const Expr *E, const VarDecl *VD) { QualType T = E->getType(); // If it's thread_local, emit a call to its wrapper function instead. if (VD->getTLSKind() == VarDecl::TLS_Dynamic && CGF.CGM.getCXXABI().usesThreadWrapperFunction()) return CGF.CGM.getCXXABI().EmitThreadLocalVarDeclLValue(CGF, VD, T); // Check if the variable is marked as declare target with link clause in // device codegen. if (CGF.getLangOpts().OpenMPIsDevice) { Address Addr = emitDeclTargetLinkVarDeclLValue(CGF, VD, T); if (Addr.isValid()) return CGF.MakeAddrLValue(Addr, T, AlignmentSource::Decl); } llvm::Value *V = CGF.CGM.GetAddrOfGlobalVar(VD); llvm::Type *RealVarTy = CGF.getTypes().ConvertTypeForMem(VD->getType()); V = EmitBitCastOfLValueToProperType(CGF, V, RealVarTy); CharUnits Alignment = CGF.getContext().getDeclAlign(VD); Address Addr(V, Alignment); // Emit reference to the private copy of the variable if it is an OpenMP // threadprivate variable. if (CGF.getLangOpts().OpenMP && !CGF.getLangOpts().OpenMPSimd && VD->hasAttr()) { return EmitThreadPrivateVarDeclLValue(CGF, VD, T, Addr, RealVarTy, E->getExprLoc()); } LValue LV = VD->getType()->isReferenceType() ? CGF.EmitLoadOfReferenceLValue(Addr, VD->getType(), AlignmentSource::Decl) : CGF.MakeAddrLValue(Addr, T, AlignmentSource::Decl); setObjCGCLValueClass(CGF.getContext(), E, LV); return LV; } static llvm::Constant *EmitFunctionDeclPointer(CodeGenModule &CGM, const FunctionDecl *FD) { if (FD->hasAttr()) { ConstantAddress aliasee = CGM.GetWeakRefReference(FD); return aliasee.getPointer(); } llvm::Constant *V = CGM.GetAddrOfFunction(FD); if (!FD->hasPrototype()) { if (const FunctionProtoType *Proto = FD->getType()->getAs()) { // Ugly case: for a K&R-style definition, the type of the definition // isn't the same as the type of a use. Correct for this with a // bitcast. QualType NoProtoType = CGM.getContext().getFunctionNoProtoType(Proto->getReturnType()); NoProtoType = CGM.getContext().getPointerType(NoProtoType); V = llvm::ConstantExpr::getBitCast(V, CGM.getTypes().ConvertType(NoProtoType)); } } return V; } static LValue EmitFunctionDeclLValue(CodeGenFunction &CGF, const Expr *E, const FunctionDecl *FD) { llvm::Value *V = EmitFunctionDeclPointer(CGF.CGM, FD); CharUnits Alignment = CGF.getContext().getDeclAlign(FD); return CGF.MakeAddrLValue(V, E->getType(), Alignment, AlignmentSource::Decl); } static LValue EmitCapturedFieldLValue(CodeGenFunction &CGF, const FieldDecl *FD, llvm::Value *ThisValue) { QualType TagType = CGF.getContext().getTagDeclType(FD->getParent()); LValue LV = CGF.MakeNaturalAlignAddrLValue(ThisValue, TagType); return CGF.EmitLValueForField(LV, FD); } /// Named Registers are named metadata pointing to the register name /// which will be read from/written to as an argument to the intrinsic /// @llvm.read/write_register. /// So far, only the name is being passed down, but other options such as /// register type, allocation type or even optimization options could be /// passed down via the metadata node. static LValue EmitGlobalNamedRegister(const VarDecl *VD, CodeGenModule &CGM) { SmallString<64> Name("llvm.named.register."); AsmLabelAttr *Asm = VD->getAttr(); assert(Asm->getLabel().size() < 64-Name.size() && "Register name too big"); Name.append(Asm->getLabel()); llvm::NamedMDNode *M = CGM.getModule().getOrInsertNamedMetadata(Name); if (M->getNumOperands() == 0) { llvm::MDString *Str = llvm::MDString::get(CGM.getLLVMContext(), Asm->getLabel()); llvm::Metadata *Ops[] = {Str}; M->addOperand(llvm::MDNode::get(CGM.getLLVMContext(), Ops)); } CharUnits Alignment = CGM.getContext().getDeclAlign(VD); llvm::Value *Ptr = llvm::MetadataAsValue::get(CGM.getLLVMContext(), M->getOperand(0)); return LValue::MakeGlobalReg(Address(Ptr, Alignment), VD->getType()); } LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) { const NamedDecl *ND = E->getDecl(); QualType T = E->getType(); if (const auto *VD = dyn_cast(ND)) { // Global Named registers access via intrinsics only if (VD->getStorageClass() == SC_Register && VD->hasAttr() && !VD->isLocalVarDecl()) return EmitGlobalNamedRegister(VD, CGM); // A DeclRefExpr for a reference initialized by a constant expression can // appear without being odr-used. Directly emit the constant initializer. const Expr *Init = VD->getAnyInitializer(VD); if (Init && !isa(VD) && VD->getType()->isReferenceType() && VD->isUsableInConstantExpressions(getContext()) && VD->checkInitIsICE() && // Do not emit if it is private OpenMP variable. !(E->refersToEnclosingVariableOrCapture() && ((CapturedStmtInfo && (LocalDeclMap.count(VD->getCanonicalDecl()) || CapturedStmtInfo->lookup(VD->getCanonicalDecl()))) || LambdaCaptureFields.lookup(VD->getCanonicalDecl()) || isa(CurCodeDecl)))) { llvm::Constant *Val = ConstantEmitter(*this).emitAbstract(E->getLocation(), *VD->evaluateValue(), VD->getType()); assert(Val && "failed to emit reference constant expression"); // FIXME: Eventually we will want to emit vector element references. // Should we be using the alignment of the constant pointer we emitted? CharUnits Alignment = getNaturalTypeAlignment(E->getType(), /* BaseInfo= */ nullptr, /* TBAAInfo= */ nullptr, /* forPointeeType= */ true); return MakeAddrLValue(Address(Val, Alignment), T, AlignmentSource::Decl); } // Check for captured variables. if (E->refersToEnclosingVariableOrCapture()) { VD = VD->getCanonicalDecl(); if (auto *FD = LambdaCaptureFields.lookup(VD)) return EmitCapturedFieldLValue(*this, FD, CXXABIThisValue); else if (CapturedStmtInfo) { auto I = LocalDeclMap.find(VD); if (I != LocalDeclMap.end()) { if (VD->getType()->isReferenceType()) return EmitLoadOfReferenceLValue(I->second, VD->getType(), AlignmentSource::Decl); return MakeAddrLValue(I->second, T); } LValue CapLVal = EmitCapturedFieldLValue(*this, CapturedStmtInfo->lookup(VD), CapturedStmtInfo->getContextValue()); return MakeAddrLValue( Address(CapLVal.getPointer(), getContext().getDeclAlign(VD)), CapLVal.getType(), LValueBaseInfo(AlignmentSource::Decl), CapLVal.getTBAAInfo()); } assert(isa(CurCodeDecl)); Address addr = GetAddrOfBlockDecl(VD, VD->hasAttr()); return MakeAddrLValue(addr, T, AlignmentSource::Decl); } } // FIXME: We should be able to assert this for FunctionDecls as well! // FIXME: We should be able to assert this for all DeclRefExprs, not just // those with a valid source location. assert((ND->isUsed(false) || !isa(ND) || !E->getLocation().isValid()) && "Should not use decl without marking it used!"); if (ND->hasAttr()) { const auto *VD = cast(ND); ConstantAddress Aliasee = CGM.GetWeakRefReference(VD); return MakeAddrLValue(Aliasee, T, AlignmentSource::Decl); } if (const auto *VD = dyn_cast(ND)) { // Check if this is a global variable. if (VD->hasLinkage() || VD->isStaticDataMember()) return EmitGlobalVarDeclLValue(*this, E, VD); Address addr = Address::invalid(); // The variable should generally be present in the local decl map. auto iter = LocalDeclMap.find(VD); if (iter != LocalDeclMap.end()) { addr = iter->second; // Otherwise, it might be static local we haven't emitted yet for // some reason; most likely, because it's in an outer function. } else if (VD->isStaticLocal()) { addr = Address(CGM.getOrCreateStaticVarDecl( *VD, CGM.getLLVMLinkageVarDefinition(VD, /*isConstant=*/false)), getContext().getDeclAlign(VD)); // No other cases for now. } else { llvm_unreachable("DeclRefExpr for Decl not entered in LocalDeclMap?"); } // Check for OpenMP threadprivate variables. if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd && VD->hasAttr()) { return EmitThreadPrivateVarDeclLValue( *this, VD, T, addr, getTypes().ConvertTypeForMem(VD->getType()), E->getExprLoc()); } // Drill into block byref variables. bool isBlockByref = VD->hasAttr(); if (isBlockByref) { addr = emitBlockByrefAddress(addr, VD); } // Drill into reference types. LValue LV = VD->getType()->isReferenceType() ? EmitLoadOfReferenceLValue(addr, VD->getType(), AlignmentSource::Decl) : MakeAddrLValue(addr, T, AlignmentSource::Decl); bool isLocalStorage = VD->hasLocalStorage(); bool NonGCable = isLocalStorage && !VD->getType()->isReferenceType() && !isBlockByref; if (NonGCable) { LV.getQuals().removeObjCGCAttr(); LV.setNonGC(true); } bool isImpreciseLifetime = (isLocalStorage && !VD->hasAttr()); if (isImpreciseLifetime) LV.setARCPreciseLifetime(ARCImpreciseLifetime); setObjCGCLValueClass(getContext(), E, LV); return LV; } if (const auto *FD = dyn_cast(ND)) return EmitFunctionDeclLValue(*this, E, FD); // FIXME: While we're emitting a binding from an enclosing scope, all other // DeclRefExprs we see should be implicitly treated as if they also refer to // an enclosing scope. if (const auto *BD = dyn_cast(ND)) return EmitLValue(BD->getBinding()); llvm_unreachable("Unhandled DeclRefExpr"); } LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) { // __extension__ doesn't affect lvalue-ness. if (E->getOpcode() == UO_Extension) return EmitLValue(E->getSubExpr()); QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType()); switch (E->getOpcode()) { default: llvm_unreachable("Unknown unary operator lvalue!"); case UO_Deref: { QualType T = E->getSubExpr()->getType()->getPointeeType(); assert(!T.isNull() && "CodeGenFunction::EmitUnaryOpLValue: Illegal type"); LValueBaseInfo BaseInfo; TBAAAccessInfo TBAAInfo; Address Addr = EmitPointerWithAlignment(E->getSubExpr(), &BaseInfo, &TBAAInfo); LValue LV = MakeAddrLValue(Addr, T, BaseInfo, TBAAInfo); LV.getQuals().setAddressSpace(ExprTy.getAddressSpace()); // We should not generate __weak write barrier on indirect reference // of a pointer to object; as in void foo (__weak id *param); *param = 0; // But, we continue to generate __strong write barrier on indirect write // into a pointer to object. if (getLangOpts().ObjC1 && getLangOpts().getGC() != LangOptions::NonGC && LV.isObjCWeak()) LV.setNonGC(!E->isOBJCGCCandidate(getContext())); return LV; } case UO_Real: case UO_Imag: { LValue LV = EmitLValue(E->getSubExpr()); assert(LV.isSimple() && "real/imag on non-ordinary l-value"); // __real is valid on scalars. This is a faster way of testing that. // __imag can only produce an rvalue on scalars. if (E->getOpcode() == UO_Real && !LV.getAddress().getElementType()->isStructTy()) { assert(E->getSubExpr()->getType()->isArithmeticType()); return LV; } QualType T = ExprTy->castAs()->getElementType(); Address Component = (E->getOpcode() == UO_Real ? emitAddrOfRealComponent(LV.getAddress(), LV.getType()) : emitAddrOfImagComponent(LV.getAddress(), LV.getType())); LValue ElemLV = MakeAddrLValue(Component, T, LV.getBaseInfo(), CGM.getTBAAInfoForSubobject(LV, T)); ElemLV.getQuals().addQualifiers(LV.getQuals()); return ElemLV; } case UO_PreInc: case UO_PreDec: { LValue LV = EmitLValue(E->getSubExpr()); bool isInc = E->getOpcode() == UO_PreInc; if (E->getType()->isAnyComplexType()) EmitComplexPrePostIncDec(E, LV, isInc, true/*isPre*/); else EmitScalarPrePostIncDec(E, LV, isInc, true/*isPre*/); return LV; } } } LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) { return MakeAddrLValue(CGM.GetAddrOfConstantStringFromLiteral(E), E->getType(), AlignmentSource::Decl); } LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) { return MakeAddrLValue(CGM.GetAddrOfConstantStringFromObjCEncode(E), E->getType(), AlignmentSource::Decl); } LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) { auto SL = E->getFunctionName(); assert(SL != nullptr && "No StringLiteral name in PredefinedExpr"); StringRef FnName = CurFn->getName(); if (FnName.startswith("\01")) FnName = FnName.substr(1); StringRef NameItems[] = { PredefinedExpr::getIdentTypeName(E->getIdentType()), FnName}; std::string GVName = llvm::join(NameItems, NameItems + 2, "."); if (auto *BD = dyn_cast_or_null(CurCodeDecl)) { std::string Name = SL->getString(); if (!Name.empty()) { unsigned Discriminator = CGM.getCXXABI().getMangleContext().getBlockId(BD, true); if (Discriminator) Name += "_" + Twine(Discriminator + 1).str(); auto C = CGM.GetAddrOfConstantCString(Name, GVName.c_str()); return MakeAddrLValue(C, E->getType(), AlignmentSource::Decl); } else { auto C = CGM.GetAddrOfConstantCString(FnName, GVName.c_str()); return MakeAddrLValue(C, E->getType(), AlignmentSource::Decl); } } auto C = CGM.GetAddrOfConstantStringFromLiteral(SL, GVName); return MakeAddrLValue(C, E->getType(), AlignmentSource::Decl); } /// Emit a type description suitable for use by a runtime sanitizer library. The /// format of a type descriptor is /// /// \code /// { i16 TypeKind, i16 TypeInfo } /// \endcode /// /// followed by an array of i8 containing the type name. TypeKind is 0 for an /// integer, 1 for a floating point value, and -1 for anything else. llvm::Constant *CodeGenFunction::EmitCheckTypeDescriptor(QualType T) { // Only emit each type's descriptor once. if (llvm::Constant *C = CGM.getTypeDescriptorFromMap(T)) return C; uint16_t TypeKind = -1; uint16_t TypeInfo = 0; if (T->isIntegerType()) { TypeKind = 0; TypeInfo = (llvm::Log2_32(getContext().getTypeSize(T)) << 1) | (T->isSignedIntegerType() ? 1 : 0); } else if (T->isFloatingType()) { TypeKind = 1; TypeInfo = getContext().getTypeSize(T); } // Format the type name as if for a diagnostic, including quotes and // optionally an 'aka'. SmallString<32> Buffer; CGM.getDiags().ConvertArgToString(DiagnosticsEngine::ak_qualtype, (intptr_t)T.getAsOpaquePtr(), StringRef(), StringRef(), None, Buffer, None); llvm::Constant *Components[] = { Builder.getInt16(TypeKind), Builder.getInt16(TypeInfo), llvm::ConstantDataArray::getString(getLLVMContext(), Buffer) }; llvm::Constant *Descriptor = llvm::ConstantStruct::getAnon(Components); auto *GV = new llvm::GlobalVariable( CGM.getModule(), Descriptor->getType(), /*isConstant=*/true, llvm::GlobalVariable::PrivateLinkage, Descriptor); GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global); CGM.getSanitizerMetadata()->disableSanitizerForGlobal(GV); // Remember the descriptor for this type. CGM.setTypeDescriptorInMap(T, GV); return GV; } llvm::Value *CodeGenFunction::EmitCheckValue(llvm::Value *V) { llvm::Type *TargetTy = IntPtrTy; if (V->getType() == TargetTy) return V; // Floating-point types which fit into intptr_t are bitcast to integers // and then passed directly (after zero-extension, if necessary). if (V->getType()->isFloatingPointTy()) { unsigned Bits = V->getType()->getPrimitiveSizeInBits(); if (Bits <= TargetTy->getIntegerBitWidth()) V = Builder.CreateBitCast(V, llvm::Type::getIntNTy(getLLVMContext(), Bits)); } // Integers which fit in intptr_t are zero-extended and passed directly. if (V->getType()->isIntegerTy() && V->getType()->getIntegerBitWidth() <= TargetTy->getIntegerBitWidth()) return Builder.CreateZExt(V, TargetTy); // Pointers are passed directly, everything else is passed by address. if (!V->getType()->isPointerTy()) { Address Ptr = CreateDefaultAlignTempAlloca(V->getType()); Builder.CreateStore(V, Ptr); V = Ptr.getPointer(); } return Builder.CreatePtrToInt(V, TargetTy); } /// Emit a representation of a SourceLocation for passing to a handler /// in a sanitizer runtime library. The format for this data is: /// \code /// struct SourceLocation { /// const char *Filename; /// int32_t Line, Column; /// }; /// \endcode /// For an invalid SourceLocation, the Filename pointer is null. llvm::Constant *CodeGenFunction::EmitCheckSourceLocation(SourceLocation Loc) { llvm::Constant *Filename; int Line, Column; PresumedLoc PLoc = getContext().getSourceManager().getPresumedLoc(Loc); if (PLoc.isValid()) { StringRef FilenameString = PLoc.getFilename(); int PathComponentsToStrip = CGM.getCodeGenOpts().EmitCheckPathComponentsToStrip; if (PathComponentsToStrip < 0) { assert(PathComponentsToStrip != INT_MIN); int PathComponentsToKeep = -PathComponentsToStrip; auto I = llvm::sys::path::rbegin(FilenameString); auto E = llvm::sys::path::rend(FilenameString); while (I != E && --PathComponentsToKeep) ++I; FilenameString = FilenameString.substr(I - E); } else if (PathComponentsToStrip > 0) { auto I = llvm::sys::path::begin(FilenameString); auto E = llvm::sys::path::end(FilenameString); while (I != E && PathComponentsToStrip--) ++I; if (I != E) FilenameString = FilenameString.substr(I - llvm::sys::path::begin(FilenameString)); else FilenameString = llvm::sys::path::filename(FilenameString); } auto FilenameGV = CGM.GetAddrOfConstantCString(FilenameString, ".src"); CGM.getSanitizerMetadata()->disableSanitizerForGlobal( cast(FilenameGV.getPointer())); Filename = FilenameGV.getPointer(); Line = PLoc.getLine(); Column = PLoc.getColumn(); } else { Filename = llvm::Constant::getNullValue(Int8PtrTy); Line = Column = 0; } llvm::Constant *Data[] = {Filename, Builder.getInt32(Line), Builder.getInt32(Column)}; return llvm::ConstantStruct::getAnon(Data); } namespace { /// Specify under what conditions this check can be recovered enum class CheckRecoverableKind { /// Always terminate program execution if this check fails. Unrecoverable, /// Check supports recovering, runtime has both fatal (noreturn) and /// non-fatal handlers for this check. Recoverable, /// Runtime conditionally aborts, always need to support recovery. AlwaysRecoverable }; } static CheckRecoverableKind getRecoverableKind(SanitizerMask Kind) { assert(llvm::countPopulation(Kind) == 1); switch (Kind) { case SanitizerKind::Vptr: return CheckRecoverableKind::AlwaysRecoverable; case SanitizerKind::Return: case SanitizerKind::Unreachable: return CheckRecoverableKind::Unrecoverable; default: return CheckRecoverableKind::Recoverable; } } namespace { struct SanitizerHandlerInfo { char const *const Name; unsigned Version; }; } const SanitizerHandlerInfo SanitizerHandlers[] = { #define SANITIZER_CHECK(Enum, Name, Version) {#Name, Version}, LIST_SANITIZER_CHECKS #undef SANITIZER_CHECK }; static void emitCheckHandlerCall(CodeGenFunction &CGF, llvm::FunctionType *FnType, ArrayRef FnArgs, SanitizerHandler CheckHandler, CheckRecoverableKind RecoverKind, bool IsFatal, llvm::BasicBlock *ContBB) { assert(IsFatal || RecoverKind != CheckRecoverableKind::Unrecoverable); bool NeedsAbortSuffix = IsFatal && RecoverKind != CheckRecoverableKind::Unrecoverable; bool MinimalRuntime = CGF.CGM.getCodeGenOpts().SanitizeMinimalRuntime; const SanitizerHandlerInfo &CheckInfo = SanitizerHandlers[CheckHandler]; const StringRef CheckName = CheckInfo.Name; std::string FnName = "__ubsan_handle_" + CheckName.str(); if (CheckInfo.Version && !MinimalRuntime) FnName += "_v" + llvm::utostr(CheckInfo.Version); if (MinimalRuntime) FnName += "_minimal"; if (NeedsAbortSuffix) FnName += "_abort"; bool MayReturn = !IsFatal || RecoverKind == CheckRecoverableKind::AlwaysRecoverable; llvm::AttrBuilder B; if (!MayReturn) { B.addAttribute(llvm::Attribute::NoReturn) .addAttribute(llvm::Attribute::NoUnwind); } B.addAttribute(llvm::Attribute::UWTable); llvm::Value *Fn = CGF.CGM.CreateRuntimeFunction( FnType, FnName, llvm::AttributeList::get(CGF.getLLVMContext(), llvm::AttributeList::FunctionIndex, B), /*Local=*/true); llvm::CallInst *HandlerCall = CGF.EmitNounwindRuntimeCall(Fn, FnArgs); if (!MayReturn) { HandlerCall->setDoesNotReturn(); CGF.Builder.CreateUnreachable(); } else { CGF.Builder.CreateBr(ContBB); } } void CodeGenFunction::EmitCheck( ArrayRef> Checked, SanitizerHandler CheckHandler, ArrayRef StaticArgs, ArrayRef DynamicArgs) { assert(IsSanitizerScope); assert(Checked.size() > 0); assert(CheckHandler >= 0 && size_t(CheckHandler) < llvm::array_lengthof(SanitizerHandlers)); const StringRef CheckName = SanitizerHandlers[CheckHandler].Name; llvm::Value *FatalCond = nullptr; llvm::Value *RecoverableCond = nullptr; llvm::Value *TrapCond = nullptr; for (int i = 0, n = Checked.size(); i < n; ++i) { llvm::Value *Check = Checked[i].first; // -fsanitize-trap= overrides -fsanitize-recover=. llvm::Value *&Cond = CGM.getCodeGenOpts().SanitizeTrap.has(Checked[i].second) ? TrapCond : CGM.getCodeGenOpts().SanitizeRecover.has(Checked[i].second) ? RecoverableCond : FatalCond; Cond = Cond ? Builder.CreateAnd(Cond, Check) : Check; } if (TrapCond) EmitTrapCheck(TrapCond); if (!FatalCond && !RecoverableCond) return; llvm::Value *JointCond; if (FatalCond && RecoverableCond) JointCond = Builder.CreateAnd(FatalCond, RecoverableCond); else JointCond = FatalCond ? FatalCond : RecoverableCond; assert(JointCond); CheckRecoverableKind RecoverKind = getRecoverableKind(Checked[0].second); assert(SanOpts.has(Checked[0].second)); #ifndef NDEBUG for (int i = 1, n = Checked.size(); i < n; ++i) { assert(RecoverKind == getRecoverableKind(Checked[i].second) && "All recoverable kinds in a single check must be same!"); assert(SanOpts.has(Checked[i].second)); } #endif llvm::BasicBlock *Cont = createBasicBlock("cont"); llvm::BasicBlock *Handlers = createBasicBlock("handler." + CheckName); llvm::Instruction *Branch = Builder.CreateCondBr(JointCond, Cont, Handlers); // Give hint that we very much don't expect to execute the handler // Value chosen to match UR_NONTAKEN_WEIGHT, see BranchProbabilityInfo.cpp llvm::MDBuilder MDHelper(getLLVMContext()); llvm::MDNode *Node = MDHelper.createBranchWeights((1U << 20) - 1, 1); Branch->setMetadata(llvm::LLVMContext::MD_prof, Node); EmitBlock(Handlers); // Handler functions take an i8* pointing to the (handler-specific) static // information block, followed by a sequence of intptr_t arguments // representing operand values. SmallVector Args; SmallVector ArgTypes; if (!CGM.getCodeGenOpts().SanitizeMinimalRuntime) { Args.reserve(DynamicArgs.size() + 1); ArgTypes.reserve(DynamicArgs.size() + 1); // Emit handler arguments and create handler function type. if (!StaticArgs.empty()) { llvm::Constant *Info = llvm::ConstantStruct::getAnon(StaticArgs); auto *InfoPtr = new llvm::GlobalVariable(CGM.getModule(), Info->getType(), false, llvm::GlobalVariable::PrivateLinkage, Info); InfoPtr->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global); CGM.getSanitizerMetadata()->disableSanitizerForGlobal(InfoPtr); Args.push_back(Builder.CreateBitCast(InfoPtr, Int8PtrTy)); ArgTypes.push_back(Int8PtrTy); } for (size_t i = 0, n = DynamicArgs.size(); i != n; ++i) { Args.push_back(EmitCheckValue(DynamicArgs[i])); ArgTypes.push_back(IntPtrTy); } } llvm::FunctionType *FnType = llvm::FunctionType::get(CGM.VoidTy, ArgTypes, false); if (!FatalCond || !RecoverableCond) { // Simple case: we need to generate a single handler call, either // fatal, or non-fatal. emitCheckHandlerCall(*this, FnType, Args, CheckHandler, RecoverKind, (FatalCond != nullptr), Cont); } else { // Emit two handler calls: first one for set of unrecoverable checks, // another one for recoverable. llvm::BasicBlock *NonFatalHandlerBB = createBasicBlock("non_fatal." + CheckName); llvm::BasicBlock *FatalHandlerBB = createBasicBlock("fatal." + CheckName); Builder.CreateCondBr(FatalCond, NonFatalHandlerBB, FatalHandlerBB); EmitBlock(FatalHandlerBB); emitCheckHandlerCall(*this, FnType, Args, CheckHandler, RecoverKind, true, NonFatalHandlerBB); EmitBlock(NonFatalHandlerBB); emitCheckHandlerCall(*this, FnType, Args, CheckHandler, RecoverKind, false, Cont); } EmitBlock(Cont); } void CodeGenFunction::EmitCfiSlowPathCheck( SanitizerMask Kind, llvm::Value *Cond, llvm::ConstantInt *TypeId, llvm::Value *Ptr, ArrayRef StaticArgs) { llvm::BasicBlock *Cont = createBasicBlock("cfi.cont"); llvm::BasicBlock *CheckBB = createBasicBlock("cfi.slowpath"); llvm::BranchInst *BI = Builder.CreateCondBr(Cond, Cont, CheckBB); llvm::MDBuilder MDHelper(getLLVMContext()); llvm::MDNode *Node = MDHelper.createBranchWeights((1U << 20) - 1, 1); BI->setMetadata(llvm::LLVMContext::MD_prof, Node); EmitBlock(CheckBB); bool WithDiag = !CGM.getCodeGenOpts().SanitizeTrap.has(Kind); llvm::CallInst *CheckCall; llvm::Constant *SlowPathFn; if (WithDiag) { llvm::Constant *Info = llvm::ConstantStruct::getAnon(StaticArgs); auto *InfoPtr = new llvm::GlobalVariable(CGM.getModule(), Info->getType(), false, llvm::GlobalVariable::PrivateLinkage, Info); InfoPtr->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global); CGM.getSanitizerMetadata()->disableSanitizerForGlobal(InfoPtr); SlowPathFn = CGM.getModule().getOrInsertFunction( "__cfi_slowpath_diag", llvm::FunctionType::get(VoidTy, {Int64Ty, Int8PtrTy, Int8PtrTy}, false)); CheckCall = Builder.CreateCall( SlowPathFn, {TypeId, Ptr, Builder.CreateBitCast(InfoPtr, Int8PtrTy)}); } else { SlowPathFn = CGM.getModule().getOrInsertFunction( "__cfi_slowpath", llvm::FunctionType::get(VoidTy, {Int64Ty, Int8PtrTy}, false)); CheckCall = Builder.CreateCall(SlowPathFn, {TypeId, Ptr}); } CGM.setDSOLocal(cast(SlowPathFn->stripPointerCasts())); CheckCall->setDoesNotThrow(); EmitBlock(Cont); } // Emit a stub for __cfi_check function so that the linker knows about this // symbol in LTO mode. void CodeGenFunction::EmitCfiCheckStub() { llvm::Module *M = &CGM.getModule(); auto &Ctx = M->getContext(); llvm::Function *F = llvm::Function::Create( llvm::FunctionType::get(VoidTy, {Int64Ty, Int8PtrTy, Int8PtrTy}, false), llvm::GlobalValue::WeakAnyLinkage, "__cfi_check", M); CGM.setDSOLocal(F); llvm::BasicBlock *BB = llvm::BasicBlock::Create(Ctx, "entry", F); // FIXME: consider emitting an intrinsic call like // call void @llvm.cfi_check(i64 %0, i8* %1, i8* %2) // which can be lowered in CrossDSOCFI pass to the actual contents of // __cfi_check. This would allow inlining of __cfi_check calls. llvm::CallInst::Create( llvm::Intrinsic::getDeclaration(M, llvm::Intrinsic::trap), "", BB); llvm::ReturnInst::Create(Ctx, nullptr, BB); } // This function is basically a switch over the CFI failure kind, which is // extracted from CFICheckFailData (1st function argument). Each case is either // llvm.trap or a call to one of the two runtime handlers, based on // -fsanitize-trap and -fsanitize-recover settings. Default case (invalid // failure kind) traps, but this should really never happen. CFICheckFailData // can be nullptr if the calling module has -fsanitize-trap behavior for this // check kind; in this case __cfi_check_fail traps as well. void CodeGenFunction::EmitCfiCheckFail() { SanitizerScope SanScope(this); FunctionArgList Args; ImplicitParamDecl ArgData(getContext(), getContext().VoidPtrTy, ImplicitParamDecl::Other); ImplicitParamDecl ArgAddr(getContext(), getContext().VoidPtrTy, ImplicitParamDecl::Other); Args.push_back(&ArgData); Args.push_back(&ArgAddr); const CGFunctionInfo &FI = CGM.getTypes().arrangeBuiltinFunctionDeclaration(getContext().VoidTy, Args); llvm::Function *F = llvm::Function::Create( llvm::FunctionType::get(VoidTy, {VoidPtrTy, VoidPtrTy}, false), llvm::GlobalValue::WeakODRLinkage, "__cfi_check_fail", &CGM.getModule()); F->setVisibility(llvm::GlobalValue::HiddenVisibility); StartFunction(GlobalDecl(), CGM.getContext().VoidTy, F, FI, Args, SourceLocation()); // This function should not be affected by blacklist. This function does // not have a source location, but "src:*" would still apply. Revert any // changes to SanOpts made in StartFunction. SanOpts = CGM.getLangOpts().Sanitize; llvm::Value *Data = EmitLoadOfScalar(GetAddrOfLocalVar(&ArgData), /*Volatile=*/false, CGM.getContext().VoidPtrTy, ArgData.getLocation()); llvm::Value *Addr = EmitLoadOfScalar(GetAddrOfLocalVar(&ArgAddr), /*Volatile=*/false, CGM.getContext().VoidPtrTy, ArgAddr.getLocation()); // Data == nullptr means the calling module has trap behaviour for this check. llvm::Value *DataIsNotNullPtr = Builder.CreateICmpNE(Data, llvm::ConstantPointerNull::get(Int8PtrTy)); EmitTrapCheck(DataIsNotNullPtr); llvm::StructType *SourceLocationTy = llvm::StructType::get(VoidPtrTy, Int32Ty, Int32Ty); llvm::StructType *CfiCheckFailDataTy = llvm::StructType::get(Int8Ty, SourceLocationTy, VoidPtrTy); llvm::Value *V = Builder.CreateConstGEP2_32( CfiCheckFailDataTy, Builder.CreatePointerCast(Data, CfiCheckFailDataTy->getPointerTo(0)), 0, 0); Address CheckKindAddr(V, getIntAlign()); llvm::Value *CheckKind = Builder.CreateLoad(CheckKindAddr); llvm::Value *AllVtables = llvm::MetadataAsValue::get( CGM.getLLVMContext(), llvm::MDString::get(CGM.getLLVMContext(), "all-vtables")); llvm::Value *ValidVtable = Builder.CreateZExt( Builder.CreateCall(CGM.getIntrinsic(llvm::Intrinsic::type_test), {Addr, AllVtables}), IntPtrTy); const std::pair CheckKinds[] = { {CFITCK_VCall, SanitizerKind::CFIVCall}, {CFITCK_NVCall, SanitizerKind::CFINVCall}, {CFITCK_DerivedCast, SanitizerKind::CFIDerivedCast}, {CFITCK_UnrelatedCast, SanitizerKind::CFIUnrelatedCast}, {CFITCK_ICall, SanitizerKind::CFIICall}}; SmallVector, 5> Checks; for (auto CheckKindMaskPair : CheckKinds) { int Kind = CheckKindMaskPair.first; SanitizerMask Mask = CheckKindMaskPair.second; llvm::Value *Cond = Builder.CreateICmpNE(CheckKind, llvm::ConstantInt::get(Int8Ty, Kind)); if (CGM.getLangOpts().Sanitize.has(Mask)) EmitCheck(std::make_pair(Cond, Mask), SanitizerHandler::CFICheckFail, {}, {Data, Addr, ValidVtable}); else EmitTrapCheck(Cond); } FinishFunction(); // The only reference to this function will be created during LTO link. // Make sure it survives until then. CGM.addUsedGlobal(F); } void CodeGenFunction::EmitUnreachable(SourceLocation Loc) { if (SanOpts.has(SanitizerKind::Unreachable)) { SanitizerScope SanScope(this); EmitCheck(std::make_pair(static_cast(Builder.getFalse()), SanitizerKind::Unreachable), SanitizerHandler::BuiltinUnreachable, EmitCheckSourceLocation(Loc), None); } Builder.CreateUnreachable(); } void CodeGenFunction::EmitTrapCheck(llvm::Value *Checked) { llvm::BasicBlock *Cont = createBasicBlock("cont"); // If we're optimizing, collapse all calls to trap down to just one per // function to save on code size. if (!CGM.getCodeGenOpts().OptimizationLevel || !TrapBB) { TrapBB = createBasicBlock("trap"); Builder.CreateCondBr(Checked, Cont, TrapBB); EmitBlock(TrapBB); llvm::CallInst *TrapCall = EmitTrapCall(llvm::Intrinsic::trap); TrapCall->setDoesNotReturn(); TrapCall->setDoesNotThrow(); Builder.CreateUnreachable(); } else { Builder.CreateCondBr(Checked, Cont, TrapBB); } EmitBlock(Cont); } llvm::CallInst *CodeGenFunction::EmitTrapCall(llvm::Intrinsic::ID IntrID) { llvm::CallInst *TrapCall = Builder.CreateCall(CGM.getIntrinsic(IntrID)); if (!CGM.getCodeGenOpts().TrapFuncName.empty()) { auto A = llvm::Attribute::get(getLLVMContext(), "trap-func-name", CGM.getCodeGenOpts().TrapFuncName); TrapCall->addAttribute(llvm::AttributeList::FunctionIndex, A); } return TrapCall; } Address CodeGenFunction::EmitArrayToPointerDecay(const Expr *E, LValueBaseInfo *BaseInfo, TBAAAccessInfo *TBAAInfo) { assert(E->getType()->isArrayType() && "Array to pointer decay must have array source type!"); // Expressions of array type can't be bitfields or vector elements. LValue LV = EmitLValue(E); Address Addr = LV.getAddress(); // If the array type was an incomplete type, we need to make sure // the decay ends up being the right type. llvm::Type *NewTy = ConvertType(E->getType()); Addr = Builder.CreateElementBitCast(Addr, NewTy); // Note that VLA pointers are always decayed, so we don't need to do // anything here. if (!E->getType()->isVariableArrayType()) { assert(isa(Addr.getElementType()) && "Expected pointer to array"); Addr = Builder.CreateStructGEP(Addr, 0, CharUnits::Zero(), "arraydecay"); } // The result of this decay conversion points to an array element within the // base lvalue. However, since TBAA currently does not support representing // accesses to elements of member arrays, we conservatively represent accesses // to the pointee object as if it had no any base lvalue specified. // TODO: Support TBAA for member arrays. QualType EltType = E->getType()->castAsArrayTypeUnsafe()->getElementType(); if (BaseInfo) *BaseInfo = LV.getBaseInfo(); if (TBAAInfo) *TBAAInfo = CGM.getTBAAAccessInfo(EltType); return Builder.CreateElementBitCast(Addr, ConvertTypeForMem(EltType)); } /// isSimpleArrayDecayOperand - If the specified expr is a simple decay from an /// array to pointer, return the array subexpression. static const Expr *isSimpleArrayDecayOperand(const Expr *E) { // If this isn't just an array->pointer decay, bail out. const auto *CE = dyn_cast(E); if (!CE || CE->getCastKind() != CK_ArrayToPointerDecay) return nullptr; // If this is a decay from variable width array, bail out. const Expr *SubExpr = CE->getSubExpr(); if (SubExpr->getType()->isVariableArrayType()) return nullptr; return SubExpr; } static llvm::Value *emitArraySubscriptGEP(CodeGenFunction &CGF, llvm::Value *ptr, ArrayRef indices, bool inbounds, bool signedIndices, SourceLocation loc, const llvm::Twine &name = "arrayidx") { if (inbounds) { return CGF.EmitCheckedInBoundsGEP(ptr, indices, signedIndices, CodeGenFunction::NotSubtraction, loc, name); } else { return CGF.Builder.CreateGEP(ptr, indices, name); } } static CharUnits getArrayElementAlign(CharUnits arrayAlign, llvm::Value *idx, CharUnits eltSize) { // If we have a constant index, we can use the exact offset of the // element we're accessing. if (auto constantIdx = dyn_cast(idx)) { CharUnits offset = constantIdx->getZExtValue() * eltSize; return arrayAlign.alignmentAtOffset(offset); // Otherwise, use the worst-case alignment for any element. } else { return arrayAlign.alignmentOfArrayElement(eltSize); } } static QualType getFixedSizeElementType(const ASTContext &ctx, const VariableArrayType *vla) { QualType eltType; do { eltType = vla->getElementType(); } while ((vla = ctx.getAsVariableArrayType(eltType))); return eltType; } static Address emitArraySubscriptGEP(CodeGenFunction &CGF, Address addr, ArrayRef indices, QualType eltType, bool inbounds, bool signedIndices, SourceLocation loc, const llvm::Twine &name = "arrayidx") { // All the indices except that last must be zero. #ifndef NDEBUG for (auto idx : indices.drop_back()) assert(isa(idx) && cast(idx)->isZero()); #endif // Determine the element size of the statically-sized base. This is // the thing that the indices are expressed in terms of. if (auto vla = CGF.getContext().getAsVariableArrayType(eltType)) { eltType = getFixedSizeElementType(CGF.getContext(), vla); } // We can use that to compute the best alignment of the element. CharUnits eltSize = CGF.getContext().getTypeSizeInChars(eltType); CharUnits eltAlign = getArrayElementAlign(addr.getAlignment(), indices.back(), eltSize); llvm::Value *eltPtr = emitArraySubscriptGEP( CGF, addr.getPointer(), indices, inbounds, signedIndices, loc, name); return Address(eltPtr, eltAlign); } LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E, bool Accessed) { // The index must always be an integer, which is not an aggregate. Emit it // in lexical order (this complexity is, sadly, required by C++17). llvm::Value *IdxPre = (E->getLHS() == E->getIdx()) ? EmitScalarExpr(E->getIdx()) : nullptr; bool SignedIndices = false; auto EmitIdxAfterBase = [&, IdxPre](bool Promote) -> llvm::Value * { auto *Idx = IdxPre; if (E->getLHS() != E->getIdx()) { assert(E->getRHS() == E->getIdx() && "index was neither LHS nor RHS"); Idx = EmitScalarExpr(E->getIdx()); } QualType IdxTy = E->getIdx()->getType(); bool IdxSigned = IdxTy->isSignedIntegerOrEnumerationType(); SignedIndices |= IdxSigned; if (SanOpts.has(SanitizerKind::ArrayBounds)) EmitBoundsCheck(E, E->getBase(), Idx, IdxTy, Accessed); // Extend or truncate the index type to 32 or 64-bits. if (Promote && Idx->getType() != IntPtrTy) Idx = Builder.CreateIntCast(Idx, IntPtrTy, IdxSigned, "idxprom"); return Idx; }; IdxPre = nullptr; // If the base is a vector type, then we are forming a vector element lvalue // with this subscript. if (E->getBase()->getType()->isVectorType() && !isa(E->getBase())) { // Emit the vector as an lvalue to get its address. LValue LHS = EmitLValue(E->getBase()); auto *Idx = EmitIdxAfterBase(/*Promote*/false); assert(LHS.isSimple() && "Can only subscript lvalue vectors here!"); return LValue::MakeVectorElt(LHS.getAddress(), Idx, E->getBase()->getType(), LHS.getBaseInfo(), TBAAAccessInfo()); } // All the other cases basically behave like simple offsetting. // Handle the extvector case we ignored above. if (isa(E->getBase())) { LValue LV = EmitLValue(E->getBase()); auto *Idx = EmitIdxAfterBase(/*Promote*/true); Address Addr = EmitExtVectorElementLValue(LV); QualType EltType = LV.getType()->castAs()->getElementType(); Addr = emitArraySubscriptGEP(*this, Addr, Idx, EltType, /*inbounds*/ true, SignedIndices, E->getExprLoc()); return MakeAddrLValue(Addr, EltType, LV.getBaseInfo(), CGM.getTBAAInfoForSubobject(LV, EltType)); } LValueBaseInfo EltBaseInfo; TBAAAccessInfo EltTBAAInfo; Address Addr = Address::invalid(); if (const VariableArrayType *vla = getContext().getAsVariableArrayType(E->getType())) { // The base must be a pointer, which is not an aggregate. Emit // it. It needs to be emitted first in case it's what captures // the VLA bounds. Addr = EmitPointerWithAlignment(E->getBase(), &EltBaseInfo, &EltTBAAInfo); auto *Idx = EmitIdxAfterBase(/*Promote*/true); // The element count here is the total number of non-VLA elements. llvm::Value *numElements = getVLASize(vla).NumElts; // Effectively, the multiply by the VLA size is part of the GEP. // GEP indexes are signed, and scaling an index isn't permitted to // signed-overflow, so we use the same semantics for our explicit // multiply. We suppress this if overflow is not undefined behavior. if (getLangOpts().isSignedOverflowDefined()) { Idx = Builder.CreateMul(Idx, numElements); } else { Idx = Builder.CreateNSWMul(Idx, numElements); } Addr = emitArraySubscriptGEP(*this, Addr, Idx, vla->getElementType(), !getLangOpts().isSignedOverflowDefined(), SignedIndices, E->getExprLoc()); } else if (const ObjCObjectType *OIT = E->getType()->getAs()){ // Indexing over an interface, as in "NSString *P; P[4];" // Emit the base pointer. Addr = EmitPointerWithAlignment(E->getBase(), &EltBaseInfo, &EltTBAAInfo); auto *Idx = EmitIdxAfterBase(/*Promote*/true); CharUnits InterfaceSize = getContext().getTypeSizeInChars(OIT); llvm::Value *InterfaceSizeVal = llvm::ConstantInt::get(Idx->getType(), InterfaceSize.getQuantity()); llvm::Value *ScaledIdx = Builder.CreateMul(Idx, InterfaceSizeVal); // We don't necessarily build correct LLVM struct types for ObjC // interfaces, so we can't rely on GEP to do this scaling // correctly, so we need to cast to i8*. FIXME: is this actually // true? A lot of other things in the fragile ABI would break... llvm::Type *OrigBaseTy = Addr.getType(); Addr = Builder.CreateElementBitCast(Addr, Int8Ty); // Do the GEP. CharUnits EltAlign = getArrayElementAlign(Addr.getAlignment(), Idx, InterfaceSize); llvm::Value *EltPtr = emitArraySubscriptGEP(*this, Addr.getPointer(), ScaledIdx, false, SignedIndices, E->getExprLoc()); Addr = Address(EltPtr, EltAlign); // Cast back. Addr = Builder.CreateBitCast(Addr, OrigBaseTy); } else if (const Expr *Array = isSimpleArrayDecayOperand(E->getBase())) { // If this is A[i] where A is an array, the frontend will have decayed the // base to be a ArrayToPointerDecay implicit cast. While correct, it is // inefficient at -O0 to emit a "gep A, 0, 0" when codegen'ing it, then a // "gep x, i" here. Emit one "gep A, 0, i". assert(Array->getType()->isArrayType() && "Array to pointer decay must have array source type!"); LValue ArrayLV; // For simple multidimensional array indexing, set the 'accessed' flag for // better bounds-checking of the base expression. if (const auto *ASE = dyn_cast(Array)) ArrayLV = EmitArraySubscriptExpr(ASE, /*Accessed*/ true); else ArrayLV = EmitLValue(Array); auto *Idx = EmitIdxAfterBase(/*Promote*/true); // Propagate the alignment from the array itself to the result. Addr = emitArraySubscriptGEP( *this, ArrayLV.getAddress(), {CGM.getSize(CharUnits::Zero()), Idx}, E->getType(), !getLangOpts().isSignedOverflowDefined(), SignedIndices, E->getExprLoc()); EltBaseInfo = ArrayLV.getBaseInfo(); EltTBAAInfo = CGM.getTBAAInfoForSubobject(ArrayLV, E->getType()); } else { // The base must be a pointer; emit it with an estimate of its alignment. Addr = EmitPointerWithAlignment(E->getBase(), &EltBaseInfo, &EltTBAAInfo); auto *Idx = EmitIdxAfterBase(/*Promote*/true); Addr = emitArraySubscriptGEP(*this, Addr, Idx, E->getType(), !getLangOpts().isSignedOverflowDefined(), SignedIndices, E->getExprLoc()); } LValue LV = MakeAddrLValue(Addr, E->getType(), EltBaseInfo, EltTBAAInfo); if (getLangOpts().ObjC1 && getLangOpts().getGC() != LangOptions::NonGC) { LV.setNonGC(!E->isOBJCGCCandidate(getContext())); setObjCGCLValueClass(getContext(), E, LV); } return LV; } static Address emitOMPArraySectionBase(CodeGenFunction &CGF, const Expr *Base, LValueBaseInfo &BaseInfo, TBAAAccessInfo &TBAAInfo, QualType BaseTy, QualType ElTy, bool IsLowerBound) { LValue BaseLVal; if (auto *ASE = dyn_cast(Base->IgnoreParenImpCasts())) { BaseLVal = CGF.EmitOMPArraySectionExpr(ASE, IsLowerBound); if (BaseTy->isArrayType()) { Address Addr = BaseLVal.getAddress(); BaseInfo = BaseLVal.getBaseInfo(); // If the array type was an incomplete type, we need to make sure // the decay ends up being the right type. llvm::Type *NewTy = CGF.ConvertType(BaseTy); Addr = CGF.Builder.CreateElementBitCast(Addr, NewTy); // Note that VLA pointers are always decayed, so we don't need to do // anything here. if (!BaseTy->isVariableArrayType()) { assert(isa(Addr.getElementType()) && "Expected pointer to array"); Addr = CGF.Builder.CreateStructGEP(Addr, 0, CharUnits::Zero(), "arraydecay"); } return CGF.Builder.CreateElementBitCast(Addr, CGF.ConvertTypeForMem(ElTy)); } LValueBaseInfo TypeBaseInfo; TBAAAccessInfo TypeTBAAInfo; CharUnits Align = CGF.getNaturalTypeAlignment(ElTy, &TypeBaseInfo, &TypeTBAAInfo); BaseInfo.mergeForCast(TypeBaseInfo); TBAAInfo = CGF.CGM.mergeTBAAInfoForCast(TBAAInfo, TypeTBAAInfo); return Address(CGF.Builder.CreateLoad(BaseLVal.getAddress()), Align); } return CGF.EmitPointerWithAlignment(Base, &BaseInfo, &TBAAInfo); } LValue CodeGenFunction::EmitOMPArraySectionExpr(const OMPArraySectionExpr *E, bool IsLowerBound) { QualType BaseTy = OMPArraySectionExpr::getBaseOriginalType(E->getBase()); QualType ResultExprTy; if (auto *AT = getContext().getAsArrayType(BaseTy)) ResultExprTy = AT->getElementType(); else ResultExprTy = BaseTy->getPointeeType(); llvm::Value *Idx = nullptr; if (IsLowerBound || E->getColonLoc().isInvalid()) { // Requesting lower bound or upper bound, but without provided length and // without ':' symbol for the default length -> length = 1. // Idx = LowerBound ?: 0; if (auto *LowerBound = E->getLowerBound()) { Idx = Builder.CreateIntCast( EmitScalarExpr(LowerBound), IntPtrTy, LowerBound->getType()->hasSignedIntegerRepresentation()); } else Idx = llvm::ConstantInt::getNullValue(IntPtrTy); } else { // Try to emit length or lower bound as constant. If this is possible, 1 // is subtracted from constant length or lower bound. Otherwise, emit LLVM // IR (LB + Len) - 1. auto &C = CGM.getContext(); auto *Length = E->getLength(); llvm::APSInt ConstLength; if (Length) { // Idx = LowerBound + Length - 1; if (Length->isIntegerConstantExpr(ConstLength, C)) { ConstLength = ConstLength.zextOrTrunc(PointerWidthInBits); Length = nullptr; } auto *LowerBound = E->getLowerBound(); llvm::APSInt ConstLowerBound(PointerWidthInBits, /*isUnsigned=*/false); if (LowerBound && LowerBound->isIntegerConstantExpr(ConstLowerBound, C)) { ConstLowerBound = ConstLowerBound.zextOrTrunc(PointerWidthInBits); LowerBound = nullptr; } if (!Length) --ConstLength; else if (!LowerBound) --ConstLowerBound; if (Length || LowerBound) { auto *LowerBoundVal = LowerBound ? Builder.CreateIntCast( EmitScalarExpr(LowerBound), IntPtrTy, LowerBound->getType()->hasSignedIntegerRepresentation()) : llvm::ConstantInt::get(IntPtrTy, ConstLowerBound); auto *LengthVal = Length ? Builder.CreateIntCast( EmitScalarExpr(Length), IntPtrTy, Length->getType()->hasSignedIntegerRepresentation()) : llvm::ConstantInt::get(IntPtrTy, ConstLength); Idx = Builder.CreateAdd(LowerBoundVal, LengthVal, "lb_add_len", /*HasNUW=*/false, !getLangOpts().isSignedOverflowDefined()); if (Length && LowerBound) { Idx = Builder.CreateSub( Idx, llvm::ConstantInt::get(IntPtrTy, /*V=*/1), "idx_sub_1", /*HasNUW=*/false, !getLangOpts().isSignedOverflowDefined()); } } else Idx = llvm::ConstantInt::get(IntPtrTy, ConstLength + ConstLowerBound); } else { // Idx = ArraySize - 1; QualType ArrayTy = BaseTy->isPointerType() ? E->getBase()->IgnoreParenImpCasts()->getType() : BaseTy; if (auto *VAT = C.getAsVariableArrayType(ArrayTy)) { Length = VAT->getSizeExpr(); if (Length->isIntegerConstantExpr(ConstLength, C)) Length = nullptr; } else { auto *CAT = C.getAsConstantArrayType(ArrayTy); ConstLength = CAT->getSize(); } if (Length) { auto *LengthVal = Builder.CreateIntCast( EmitScalarExpr(Length), IntPtrTy, Length->getType()->hasSignedIntegerRepresentation()); Idx = Builder.CreateSub( LengthVal, llvm::ConstantInt::get(IntPtrTy, /*V=*/1), "len_sub_1", /*HasNUW=*/false, !getLangOpts().isSignedOverflowDefined()); } else { ConstLength = ConstLength.zextOrTrunc(PointerWidthInBits); --ConstLength; Idx = llvm::ConstantInt::get(IntPtrTy, ConstLength); } } } assert(Idx); Address EltPtr = Address::invalid(); LValueBaseInfo BaseInfo; TBAAAccessInfo TBAAInfo; if (auto *VLA = getContext().getAsVariableArrayType(ResultExprTy)) { // The base must be a pointer, which is not an aggregate. Emit // it. It needs to be emitted first in case it's what captures // the VLA bounds. Address Base = emitOMPArraySectionBase(*this, E->getBase(), BaseInfo, TBAAInfo, BaseTy, VLA->getElementType(), IsLowerBound); // The element count here is the total number of non-VLA elements. llvm::Value *NumElements = getVLASize(VLA).NumElts; // Effectively, the multiply by the VLA size is part of the GEP. // GEP indexes are signed, and scaling an index isn't permitted to // signed-overflow, so we use the same semantics for our explicit // multiply. We suppress this if overflow is not undefined behavior. if (getLangOpts().isSignedOverflowDefined()) Idx = Builder.CreateMul(Idx, NumElements); else Idx = Builder.CreateNSWMul(Idx, NumElements); EltPtr = emitArraySubscriptGEP(*this, Base, Idx, VLA->getElementType(), !getLangOpts().isSignedOverflowDefined(), /*SignedIndices=*/false, E->getExprLoc()); } else if (const Expr *Array = isSimpleArrayDecayOperand(E->getBase())) { // If this is A[i] where A is an array, the frontend will have decayed the // base to be a ArrayToPointerDecay implicit cast. While correct, it is // inefficient at -O0 to emit a "gep A, 0, 0" when codegen'ing it, then a // "gep x, i" here. Emit one "gep A, 0, i". assert(Array->getType()->isArrayType() && "Array to pointer decay must have array source type!"); LValue ArrayLV; // For simple multidimensional array indexing, set the 'accessed' flag for // better bounds-checking of the base expression. if (const auto *ASE = dyn_cast(Array)) ArrayLV = EmitArraySubscriptExpr(ASE, /*Accessed*/ true); else ArrayLV = EmitLValue(Array); // Propagate the alignment from the array itself to the result. EltPtr = emitArraySubscriptGEP( *this, ArrayLV.getAddress(), {CGM.getSize(CharUnits::Zero()), Idx}, ResultExprTy, !getLangOpts().isSignedOverflowDefined(), /*SignedIndices=*/false, E->getExprLoc()); BaseInfo = ArrayLV.getBaseInfo(); TBAAInfo = CGM.getTBAAInfoForSubobject(ArrayLV, ResultExprTy); } else { Address Base = emitOMPArraySectionBase(*this, E->getBase(), BaseInfo, TBAAInfo, BaseTy, ResultExprTy, IsLowerBound); EltPtr = emitArraySubscriptGEP(*this, Base, Idx, ResultExprTy, !getLangOpts().isSignedOverflowDefined(), /*SignedIndices=*/false, E->getExprLoc()); } return MakeAddrLValue(EltPtr, ResultExprTy, BaseInfo, TBAAInfo); } LValue CodeGenFunction:: EmitExtVectorElementExpr(const ExtVectorElementExpr *E) { // Emit the base vector as an l-value. LValue Base; // ExtVectorElementExpr's base can either be a vector or pointer to vector. if (E->isArrow()) { // If it is a pointer to a vector, emit the address and form an lvalue with // it. LValueBaseInfo BaseInfo; TBAAAccessInfo TBAAInfo; Address Ptr = EmitPointerWithAlignment(E->getBase(), &BaseInfo, &TBAAInfo); const PointerType *PT = E->getBase()->getType()->getAs(); Base = MakeAddrLValue(Ptr, PT->getPointeeType(), BaseInfo, TBAAInfo); Base.getQuals().removeObjCGCAttr(); } else if (E->getBase()->isGLValue()) { // Otherwise, if the base is an lvalue ( as in the case of foo.x.x), // emit the base as an lvalue. assert(E->getBase()->getType()->isVectorType()); Base = EmitLValue(E->getBase()); } else { // Otherwise, the base is a normal rvalue (as in (V+V).x), emit it as such. assert(E->getBase()->getType()->isVectorType() && "Result must be a vector"); llvm::Value *Vec = EmitScalarExpr(E->getBase()); // Store the vector to memory (because LValue wants an address). Address VecMem = CreateMemTemp(E->getBase()->getType()); Builder.CreateStore(Vec, VecMem); Base = MakeAddrLValue(VecMem, E->getBase()->getType(), AlignmentSource::Decl); } QualType type = E->getType().withCVRQualifiers(Base.getQuals().getCVRQualifiers()); // Encode the element access list into a vector of unsigned indices. SmallVector Indices; E->getEncodedElementAccess(Indices); if (Base.isSimple()) { llvm::Constant *CV = llvm::ConstantDataVector::get(getLLVMContext(), Indices); return LValue::MakeExtVectorElt(Base.getAddress(), CV, type, Base.getBaseInfo(), TBAAAccessInfo()); } assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!"); llvm::Constant *BaseElts = Base.getExtVectorElts(); SmallVector CElts; for (unsigned i = 0, e = Indices.size(); i != e; ++i) CElts.push_back(BaseElts->getAggregateElement(Indices[i])); llvm::Constant *CV = llvm::ConstantVector::get(CElts); return LValue::MakeExtVectorElt(Base.getExtVectorAddress(), CV, type, Base.getBaseInfo(), TBAAAccessInfo()); } LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) { if (DeclRefExpr *DRE = tryToConvertMemberExprToDeclRefExpr(*this, E)) { EmitIgnoredExpr(E->getBase()); return EmitDeclRefLValue(DRE); } Expr *BaseExpr = E->getBase(); // If this is s.x, emit s as an lvalue. If it is s->x, emit s as a scalar. LValue BaseLV; if (E->isArrow()) { LValueBaseInfo BaseInfo; TBAAAccessInfo TBAAInfo; Address Addr = EmitPointerWithAlignment(BaseExpr, &BaseInfo, &TBAAInfo); QualType PtrTy = BaseExpr->getType()->getPointeeType(); SanitizerSet SkippedChecks; bool IsBaseCXXThis = IsWrappedCXXThis(BaseExpr); if (IsBaseCXXThis) SkippedChecks.set(SanitizerKind::Alignment, true); if (IsBaseCXXThis || isa(BaseExpr)) SkippedChecks.set(SanitizerKind::Null, true); EmitTypeCheck(TCK_MemberAccess, E->getExprLoc(), Addr.getPointer(), PtrTy, /*Alignment=*/CharUnits::Zero(), SkippedChecks); BaseLV = MakeAddrLValue(Addr, PtrTy, BaseInfo, TBAAInfo); } else BaseLV = EmitCheckedLValue(BaseExpr, TCK_MemberAccess); NamedDecl *ND = E->getMemberDecl(); if (auto *Field = dyn_cast(ND)) { LValue LV = EmitLValueForField(BaseLV, Field); setObjCGCLValueClass(getContext(), E, LV); return LV; } if (const auto *FD = dyn_cast(ND)) return EmitFunctionDeclLValue(*this, E, FD); llvm_unreachable("Unhandled member declaration!"); } /// Given that we are currently emitting a lambda, emit an l-value for /// one of its members. LValue CodeGenFunction::EmitLValueForLambdaField(const FieldDecl *Field) { assert(cast(CurCodeDecl)->getParent()->isLambda()); assert(cast(CurCodeDecl)->getParent() == Field->getParent()); QualType LambdaTagType = getContext().getTagDeclType(Field->getParent()); LValue LambdaLV = MakeNaturalAlignAddrLValue(CXXABIThisValue, LambdaTagType); return EmitLValueForField(LambdaLV, Field); } /// Drill down to the storage of a field without walking into /// reference types. /// /// The resulting address doesn't necessarily have the right type. static Address emitAddrOfFieldStorage(CodeGenFunction &CGF, Address base, const FieldDecl *field) { const RecordDecl *rec = field->getParent(); unsigned idx = CGF.CGM.getTypes().getCGRecordLayout(rec).getLLVMFieldNo(field); CharUnits offset; // Adjust the alignment down to the given offset. // As a special case, if the LLVM field index is 0, we know that this // is zero. assert((idx != 0 || CGF.getContext().getASTRecordLayout(rec) .getFieldOffset(field->getFieldIndex()) == 0) && "LLVM field at index zero had non-zero offset?"); if (idx != 0) { auto &recLayout = CGF.getContext().getASTRecordLayout(rec); auto offsetInBits = recLayout.getFieldOffset(field->getFieldIndex()); offset = CGF.getContext().toCharUnitsFromBits(offsetInBits); } return CGF.Builder.CreateStructGEP(base, idx, offset, field->getName()); } static bool hasAnyVptr(const QualType Type, const ASTContext &Context) { const auto *RD = Type.getTypePtr()->getAsCXXRecordDecl(); if (!RD) return false; if (RD->isDynamicClass()) return true; for (const auto &Base : RD->bases()) if (hasAnyVptr(Base.getType(), Context)) return true; for (const FieldDecl *Field : RD->fields()) if (hasAnyVptr(Field->getType(), Context)) return true; return false; } LValue CodeGenFunction::EmitLValueForField(LValue base, const FieldDecl *field) { LValueBaseInfo BaseInfo = base.getBaseInfo(); if (field->isBitField()) { const CGRecordLayout &RL = CGM.getTypes().getCGRecordLayout(field->getParent()); const CGBitFieldInfo &Info = RL.getBitFieldInfo(field); Address Addr = base.getAddress(); unsigned Idx = RL.getLLVMFieldNo(field); if (Idx != 0) // For structs, we GEP to the field that the record layout suggests. Addr = Builder.CreateStructGEP(Addr, Idx, Info.StorageOffset, field->getName()); // Get the access type. llvm::Type *FieldIntTy = llvm::Type::getIntNTy(getLLVMContext(), Info.StorageSize); if (Addr.getElementType() != FieldIntTy) Addr = Builder.CreateElementBitCast(Addr, FieldIntTy); QualType fieldType = field->getType().withCVRQualifiers(base.getVRQualifiers()); // TODO: Support TBAA for bit fields. LValueBaseInfo FieldBaseInfo(BaseInfo.getAlignmentSource()); return LValue::MakeBitfield(Addr, Info, fieldType, FieldBaseInfo, TBAAAccessInfo()); } // Fields of may-alias structures are may-alias themselves. // FIXME: this should get propagated down through anonymous structs // and unions. QualType FieldType = field->getType(); const RecordDecl *rec = field->getParent(); AlignmentSource BaseAlignSource = BaseInfo.getAlignmentSource(); LValueBaseInfo FieldBaseInfo(getFieldAlignmentSource(BaseAlignSource)); TBAAAccessInfo FieldTBAAInfo; if (base.getTBAAInfo().isMayAlias() || rec->hasAttr() || FieldType->isVectorType()) { FieldTBAAInfo = TBAAAccessInfo::getMayAliasInfo(); } else if (rec->isUnion()) { // TODO: Support TBAA for unions. FieldTBAAInfo = TBAAAccessInfo::getMayAliasInfo(); } else { // If no base type been assigned for the base access, then try to generate // one for this base lvalue. FieldTBAAInfo = base.getTBAAInfo(); if (!FieldTBAAInfo.BaseType) { FieldTBAAInfo.BaseType = CGM.getTBAABaseTypeInfo(base.getType()); assert(!FieldTBAAInfo.Offset && "Nonzero offset for an access with no base type!"); } // Adjust offset to be relative to the base type. const ASTRecordLayout &Layout = getContext().getASTRecordLayout(field->getParent()); unsigned CharWidth = getContext().getCharWidth(); if (FieldTBAAInfo.BaseType) FieldTBAAInfo.Offset += Layout.getFieldOffset(field->getFieldIndex()) / CharWidth; // Update the final access type and size. FieldTBAAInfo.AccessType = CGM.getTBAATypeInfo(FieldType); FieldTBAAInfo.Size = getContext().getTypeSizeInChars(FieldType).getQuantity(); } Address addr = base.getAddress(); if (auto *ClassDef = dyn_cast(rec)) { if (CGM.getCodeGenOpts().StrictVTablePointers && ClassDef->isDynamicClass()) { // Getting to any field of dynamic object requires stripping dynamic // information provided by invariant.group. This is because accessing // fields may leak the real address of dynamic object, which could result // in miscompilation when leaked pointer would be compared. auto *stripped = Builder.CreateStripInvariantGroup(addr.getPointer()); addr = Address(stripped, addr.getAlignment()); } } unsigned RecordCVR = base.getVRQualifiers(); if (rec->isUnion()) { // For unions, there is no pointer adjustment. assert(!FieldType->isReferenceType() && "union has reference member"); if (CGM.getCodeGenOpts().StrictVTablePointers && hasAnyVptr(FieldType, getContext())) // Because unions can easily skip invariant.barriers, we need to add // a barrier every time CXXRecord field with vptr is referenced. addr = Address(Builder.CreateLaunderInvariantGroup(addr.getPointer()), addr.getAlignment()); } else { // For structs, we GEP to the field that the record layout suggests. addr = emitAddrOfFieldStorage(*this, addr, field); // If this is a reference field, load the reference right now. if (FieldType->isReferenceType()) { LValue RefLVal = MakeAddrLValue(addr, FieldType, FieldBaseInfo, FieldTBAAInfo); if (RecordCVR & Qualifiers::Volatile) RefLVal.getQuals().setVolatile(true); addr = EmitLoadOfReference(RefLVal, &FieldBaseInfo, &FieldTBAAInfo); // Qualifiers on the struct don't apply to the referencee. RecordCVR = 0; FieldType = FieldType->getPointeeType(); } } // Make sure that the address is pointing to the right type. This is critical // for both unions and structs. A union needs a bitcast, a struct element // will need a bitcast if the LLVM type laid out doesn't match the desired // type. addr = Builder.CreateElementBitCast( addr, CGM.getTypes().ConvertTypeForMem(FieldType), field->getName()); if (field->hasAttr()) addr = EmitFieldAnnotations(field, addr); LValue LV = MakeAddrLValue(addr, FieldType, FieldBaseInfo, FieldTBAAInfo); LV.getQuals().addCVRQualifiers(RecordCVR); // __weak attribute on a field is ignored. if (LV.getQuals().getObjCGCAttr() == Qualifiers::Weak) LV.getQuals().removeObjCGCAttr(); return LV; } LValue CodeGenFunction::EmitLValueForFieldInitialization(LValue Base, const FieldDecl *Field) { QualType FieldType = Field->getType(); if (!FieldType->isReferenceType()) return EmitLValueForField(Base, Field); Address V = emitAddrOfFieldStorage(*this, Base.getAddress(), Field); // Make sure that the address is pointing to the right type. llvm::Type *llvmType = ConvertTypeForMem(FieldType); V = Builder.CreateElementBitCast(V, llvmType, Field->getName()); // TODO: Generate TBAA information that describes this access as a structure // member access and not just an access to an object of the field's type. This // should be similar to what we do in EmitLValueForField(). LValueBaseInfo BaseInfo = Base.getBaseInfo(); AlignmentSource FieldAlignSource = BaseInfo.getAlignmentSource(); LValueBaseInfo FieldBaseInfo(getFieldAlignmentSource(FieldAlignSource)); return MakeAddrLValue(V, FieldType, FieldBaseInfo, CGM.getTBAAInfoForSubobject(Base, FieldType)); } LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr *E){ if (E->isFileScope()) { ConstantAddress GlobalPtr = CGM.GetAddrOfConstantCompoundLiteral(E); return MakeAddrLValue(GlobalPtr, E->getType(), AlignmentSource::Decl); } if (E->getType()->isVariablyModifiedType()) // make sure to emit the VLA size. EmitVariablyModifiedType(E->getType()); Address DeclPtr = CreateMemTemp(E->getType(), ".compoundliteral"); const Expr *InitExpr = E->getInitializer(); LValue Result = MakeAddrLValue(DeclPtr, E->getType(), AlignmentSource::Decl); EmitAnyExprToMem(InitExpr, DeclPtr, E->getType().getQualifiers(), /*Init*/ true); return Result; } LValue CodeGenFunction::EmitInitListLValue(const InitListExpr *E) { if (!E->isGLValue()) // Initializing an aggregate temporary in C++11: T{...}. return EmitAggExprToLValue(E); // An lvalue initializer list must be initializing a reference. assert(E->isTransparent() && "non-transparent glvalue init list"); return EmitLValue(E->getInit(0)); } /// Emit the operand of a glvalue conditional operator. This is either a glvalue /// or a (possibly-parenthesized) throw-expression. If this is a throw, no /// LValue is returned and the current block has been terminated. static Optional EmitLValueOrThrowExpression(CodeGenFunction &CGF, const Expr *Operand) { if (auto *ThrowExpr = dyn_cast(Operand->IgnoreParens())) { CGF.EmitCXXThrowExpr(ThrowExpr, /*KeepInsertionPoint*/false); return None; } return CGF.EmitLValue(Operand); } LValue CodeGenFunction:: EmitConditionalOperatorLValue(const AbstractConditionalOperator *expr) { if (!expr->isGLValue()) { // ?: here should be an aggregate. assert(hasAggregateEvaluationKind(expr->getType()) && "Unexpected conditional operator!"); return EmitAggExprToLValue(expr); } OpaqueValueMapping binding(*this, expr); const Expr *condExpr = expr->getCond(); bool CondExprBool; if (ConstantFoldsToSimpleInteger(condExpr, CondExprBool)) { const Expr *live = expr->getTrueExpr(), *dead = expr->getFalseExpr(); if (!CondExprBool) std::swap(live, dead); if (!ContainsLabel(dead)) { // If the true case is live, we need to track its region. if (CondExprBool) incrementProfileCounter(expr); return EmitLValue(live); } } llvm::BasicBlock *lhsBlock = createBasicBlock("cond.true"); llvm::BasicBlock *rhsBlock = createBasicBlock("cond.false"); llvm::BasicBlock *contBlock = createBasicBlock("cond.end"); ConditionalEvaluation eval(*this); EmitBranchOnBoolExpr(condExpr, lhsBlock, rhsBlock, getProfileCount(expr)); // Any temporaries created here are conditional. EmitBlock(lhsBlock); incrementProfileCounter(expr); eval.begin(*this); Optional lhs = EmitLValueOrThrowExpression(*this, expr->getTrueExpr()); eval.end(*this); if (lhs && !lhs->isSimple()) return EmitUnsupportedLValue(expr, "conditional operator"); lhsBlock = Builder.GetInsertBlock(); if (lhs) Builder.CreateBr(contBlock); // Any temporaries created here are conditional. EmitBlock(rhsBlock); eval.begin(*this); Optional rhs = EmitLValueOrThrowExpression(*this, expr->getFalseExpr()); eval.end(*this); if (rhs && !rhs->isSimple()) return EmitUnsupportedLValue(expr, "conditional operator"); rhsBlock = Builder.GetInsertBlock(); EmitBlock(contBlock); if (lhs && rhs) { llvm::PHINode *phi = Builder.CreatePHI(lhs->getPointer()->getType(), 2, "cond-lvalue"); phi->addIncoming(lhs->getPointer(), lhsBlock); phi->addIncoming(rhs->getPointer(), rhsBlock); Address result(phi, std::min(lhs->getAlignment(), rhs->getAlignment())); AlignmentSource alignSource = std::max(lhs->getBaseInfo().getAlignmentSource(), rhs->getBaseInfo().getAlignmentSource()); TBAAAccessInfo TBAAInfo = CGM.mergeTBAAInfoForConditionalOperator( lhs->getTBAAInfo(), rhs->getTBAAInfo()); return MakeAddrLValue(result, expr->getType(), LValueBaseInfo(alignSource), TBAAInfo); } else { assert((lhs || rhs) && "both operands of glvalue conditional are throw-expressions?"); return lhs ? *lhs : *rhs; } } /// EmitCastLValue - Casts are never lvalues unless that cast is to a reference /// type. If the cast is to a reference, we can have the usual lvalue result, /// otherwise if a cast is needed by the code generator in an lvalue context, /// then it must mean that we need the address of an aggregate in order to /// access one of its members. This can happen for all the reasons that casts /// are permitted with aggregate result, including noop aggregate casts, and /// cast from scalar to union. LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) { switch (E->getCastKind()) { case CK_ToVoid: case CK_BitCast: case CK_ArrayToPointerDecay: case CK_FunctionToPointerDecay: case CK_NullToMemberPointer: case CK_NullToPointer: case CK_IntegralToPointer: case CK_PointerToIntegral: case CK_PointerToBoolean: case CK_VectorSplat: case CK_IntegralCast: case CK_BooleanToSignedIntegral: case CK_IntegralToBoolean: case CK_IntegralToFloating: case CK_FloatingToIntegral: case CK_FloatingToBoolean: case CK_FloatingCast: case CK_FloatingRealToComplex: case CK_FloatingComplexToReal: case CK_FloatingComplexToBoolean: case CK_FloatingComplexCast: case CK_FloatingComplexToIntegralComplex: case CK_IntegralRealToComplex: case CK_IntegralComplexToReal: case CK_IntegralComplexToBoolean: case CK_IntegralComplexCast: case CK_IntegralComplexToFloatingComplex: case CK_DerivedToBaseMemberPointer: case CK_BaseToDerivedMemberPointer: case CK_MemberPointerToBoolean: case CK_ReinterpretMemberPointer: case CK_AnyPointerToBlockPointerCast: case CK_ARCProduceObject: case CK_ARCConsumeObject: case CK_ARCReclaimReturnedObject: case CK_ARCExtendBlockObject: case CK_CopyAndAutoreleaseBlockObject: case CK_AddressSpaceConversion: case CK_IntToOCLSampler: return EmitUnsupportedLValue(E, "unexpected cast lvalue"); case CK_Dependent: llvm_unreachable("dependent cast kind in IR gen!"); case CK_BuiltinFnToFnPtr: llvm_unreachable("builtin functions are handled elsewhere"); // These are never l-values; just use the aggregate emission code. case CK_NonAtomicToAtomic: case CK_AtomicToNonAtomic: return EmitAggExprToLValue(E); case CK_Dynamic: { LValue LV = EmitLValue(E->getSubExpr()); Address V = LV.getAddress(); const auto *DCE = cast(E); return MakeNaturalAlignAddrLValue(EmitDynamicCast(V, DCE), E->getType()); } case CK_ConstructorConversion: case CK_UserDefinedConversion: case CK_CPointerToObjCPointerCast: case CK_BlockPointerToObjCPointerCast: case CK_NoOp: case CK_LValueToRValue: return EmitLValue(E->getSubExpr()); case CK_UncheckedDerivedToBase: case CK_DerivedToBase: { const RecordType *DerivedClassTy = E->getSubExpr()->getType()->getAs(); auto *DerivedClassDecl = cast(DerivedClassTy->getDecl()); LValue LV = EmitLValue(E->getSubExpr()); Address This = LV.getAddress(); // Perform the derived-to-base conversion Address Base = GetAddressOfBaseClass( This, DerivedClassDecl, E->path_begin(), E->path_end(), /*NullCheckValue=*/false, E->getExprLoc()); // TODO: Support accesses to members of base classes in TBAA. For now, we // conservatively pretend that the complete object is of the base class // type. return MakeAddrLValue(Base, E->getType(), LV.getBaseInfo(), CGM.getTBAAInfoForSubobject(LV, E->getType())); } case CK_ToUnion: return EmitAggExprToLValue(E); case CK_BaseToDerived: { const RecordType *DerivedClassTy = E->getType()->getAs(); auto *DerivedClassDecl = cast(DerivedClassTy->getDecl()); LValue LV = EmitLValue(E->getSubExpr()); // Perform the base-to-derived conversion Address Derived = GetAddressOfDerivedClass(LV.getAddress(), DerivedClassDecl, E->path_begin(), E->path_end(), /*NullCheckValue=*/false); // C++11 [expr.static.cast]p2: Behavior is undefined if a downcast is // performed and the object is not of the derived type. if (sanitizePerformTypeCheck()) EmitTypeCheck(TCK_DowncastReference, E->getExprLoc(), Derived.getPointer(), E->getType()); if (SanOpts.has(SanitizerKind::CFIDerivedCast)) EmitVTablePtrCheckForCast(E->getType(), Derived.getPointer(), /*MayBeNull=*/false, CFITCK_DerivedCast, E->getLocStart()); return MakeAddrLValue(Derived, E->getType(), LV.getBaseInfo(), CGM.getTBAAInfoForSubobject(LV, E->getType())); } case CK_LValueBitCast: { // This must be a reinterpret_cast (or c-style equivalent). const auto *CE = cast(E); CGM.EmitExplicitCastExprType(CE, this); LValue LV = EmitLValue(E->getSubExpr()); Address V = Builder.CreateBitCast(LV.getAddress(), ConvertType(CE->getTypeAsWritten())); if (SanOpts.has(SanitizerKind::CFIUnrelatedCast)) EmitVTablePtrCheckForCast(E->getType(), V.getPointer(), /*MayBeNull=*/false, CFITCK_UnrelatedCast, E->getLocStart()); return MakeAddrLValue(V, E->getType(), LV.getBaseInfo(), CGM.getTBAAInfoForSubobject(LV, E->getType())); } case CK_ObjCObjectLValueCast: { LValue LV = EmitLValue(E->getSubExpr()); Address V = Builder.CreateElementBitCast(LV.getAddress(), ConvertType(E->getType())); return MakeAddrLValue(V, E->getType(), LV.getBaseInfo(), CGM.getTBAAInfoForSubobject(LV, E->getType())); } case CK_ZeroToOCLQueue: llvm_unreachable("NULL to OpenCL queue lvalue cast is not valid"); case CK_ZeroToOCLEvent: llvm_unreachable("NULL to OpenCL event lvalue cast is not valid"); } llvm_unreachable("Unhandled lvalue cast kind?"); } LValue CodeGenFunction::EmitOpaqueValueLValue(const OpaqueValueExpr *e) { assert(OpaqueValueMappingData::shouldBindAsLValue(e)); return getOrCreateOpaqueLValueMapping(e); } LValue CodeGenFunction::getOrCreateOpaqueLValueMapping(const OpaqueValueExpr *e) { assert(OpaqueValueMapping::shouldBindAsLValue(e)); llvm::DenseMap::iterator it = OpaqueLValues.find(e); if (it != OpaqueLValues.end()) return it->second; assert(e->isUnique() && "LValue for a nonunique OVE hasn't been emitted"); return EmitLValue(e->getSourceExpr()); } RValue CodeGenFunction::getOrCreateOpaqueRValueMapping(const OpaqueValueExpr *e) { assert(!OpaqueValueMapping::shouldBindAsLValue(e)); llvm::DenseMap::iterator it = OpaqueRValues.find(e); if (it != OpaqueRValues.end()) return it->second; assert(e->isUnique() && "RValue for a nonunique OVE hasn't been emitted"); return EmitAnyExpr(e->getSourceExpr()); } RValue CodeGenFunction::EmitRValueForField(LValue LV, const FieldDecl *FD, SourceLocation Loc) { QualType FT = FD->getType(); LValue FieldLV = EmitLValueForField(LV, FD); switch (getEvaluationKind(FT)) { case TEK_Complex: return RValue::getComplex(EmitLoadOfComplex(FieldLV, Loc)); case TEK_Aggregate: return FieldLV.asAggregateRValue(); case TEK_Scalar: // This routine is used to load fields one-by-one to perform a copy, so // don't load reference fields. if (FD->getType()->isReferenceType()) return RValue::get(FieldLV.getPointer()); return EmitLoadOfLValue(FieldLV, Loc); } llvm_unreachable("bad evaluation kind"); } //===--------------------------------------------------------------------===// // Expression Emission //===--------------------------------------------------------------------===// RValue CodeGenFunction::EmitCallExpr(const CallExpr *E, ReturnValueSlot ReturnValue) { // Builtins never have block type. if (E->getCallee()->getType()->isBlockPointerType()) return EmitBlockCallExpr(E, ReturnValue); if (const auto *CE = dyn_cast(E)) return EmitCXXMemberCallExpr(CE, ReturnValue); if (const auto *CE = dyn_cast(E)) return EmitCUDAKernelCallExpr(CE, ReturnValue); if (const auto *CE = dyn_cast(E)) if (const CXXMethodDecl *MD = dyn_cast_or_null(CE->getCalleeDecl())) return EmitCXXOperatorMemberCallExpr(CE, MD, ReturnValue); CGCallee callee = EmitCallee(E->getCallee()); if (callee.isBuiltin()) { return EmitBuiltinExpr(callee.getBuiltinDecl(), callee.getBuiltinID(), E, ReturnValue); } if (callee.isPseudoDestructor()) { return EmitCXXPseudoDestructorExpr(callee.getPseudoDestructorExpr()); } return EmitCall(E->getCallee()->getType(), callee, E, ReturnValue); } /// Emit a CallExpr without considering whether it might be a subclass. RValue CodeGenFunction::EmitSimpleCallExpr(const CallExpr *E, ReturnValueSlot ReturnValue) { CGCallee Callee = EmitCallee(E->getCallee()); return EmitCall(E->getCallee()->getType(), Callee, E, ReturnValue); } static CGCallee EmitDirectCallee(CodeGenFunction &CGF, const FunctionDecl *FD) { if (auto builtinID = FD->getBuiltinID()) { return CGCallee::forBuiltin(builtinID, FD); } llvm::Constant *calleePtr = EmitFunctionDeclPointer(CGF.CGM, FD); return CGCallee::forDirect(calleePtr, FD); } CGCallee CodeGenFunction::EmitCallee(const Expr *E) { E = E->IgnoreParens(); // Look through function-to-pointer decay. if (auto ICE = dyn_cast(E)) { if (ICE->getCastKind() == CK_FunctionToPointerDecay || ICE->getCastKind() == CK_BuiltinFnToFnPtr) { return EmitCallee(ICE->getSubExpr()); } // Resolve direct calls. } else if (auto DRE = dyn_cast(E)) { if (auto FD = dyn_cast(DRE->getDecl())) { return EmitDirectCallee(*this, FD); } } else if (auto ME = dyn_cast(E)) { if (auto FD = dyn_cast(ME->getMemberDecl())) { EmitIgnoredExpr(ME->getBase()); return EmitDirectCallee(*this, FD); } // Look through template substitutions. } else if (auto NTTP = dyn_cast(E)) { return EmitCallee(NTTP->getReplacement()); // Treat pseudo-destructor calls differently. } else if (auto PDE = dyn_cast(E)) { return CGCallee::forPseudoDestructor(PDE); } // Otherwise, we have an indirect reference. llvm::Value *calleePtr; QualType functionType; if (auto ptrType = E->getType()->getAs()) { calleePtr = EmitScalarExpr(E); functionType = ptrType->getPointeeType(); } else { functionType = E->getType(); calleePtr = EmitLValue(E).getPointer(); } assert(functionType->isFunctionType()); CGCalleeInfo calleeInfo(functionType->getAs(), E->getReferencedDeclOfCallee()); CGCallee callee(calleeInfo, calleePtr); return callee; } LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) { // Comma expressions just emit their LHS then their RHS as an l-value. if (E->getOpcode() == BO_Comma) { EmitIgnoredExpr(E->getLHS()); EnsureInsertPoint(); return EmitLValue(E->getRHS()); } if (E->getOpcode() == BO_PtrMemD || E->getOpcode() == BO_PtrMemI) return EmitPointerToDataMemberBinaryExpr(E); assert(E->getOpcode() == BO_Assign && "unexpected binary l-value"); // Note that in all of these cases, __block variables need the RHS // evaluated first just in case the variable gets moved by the RHS. switch (getEvaluationKind(E->getType())) { case TEK_Scalar: { switch (E->getLHS()->getType().getObjCLifetime()) { case Qualifiers::OCL_Strong: return EmitARCStoreStrong(E, /*ignored*/ false).first; case Qualifiers::OCL_Autoreleasing: return EmitARCStoreAutoreleasing(E).first; // No reason to do any of these differently. case Qualifiers::OCL_None: case Qualifiers::OCL_ExplicitNone: case Qualifiers::OCL_Weak: break; } RValue RV = EmitAnyExpr(E->getRHS()); LValue LV = EmitCheckedLValue(E->getLHS(), TCK_Store); if (RV.isScalar()) EmitNullabilityCheck(LV, RV.getScalarVal(), E->getExprLoc()); EmitStoreThroughLValue(RV, LV); return LV; } case TEK_Complex: return EmitComplexAssignmentLValue(E); case TEK_Aggregate: return EmitAggExprToLValue(E); } llvm_unreachable("bad evaluation kind"); } LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) { RValue RV = EmitCallExpr(E); if (!RV.isScalar()) return MakeAddrLValue(RV.getAggregateAddress(), E->getType(), AlignmentSource::Decl); assert(E->getCallReturnType(getContext())->isReferenceType() && "Can't have a scalar return unless the return type is a " "reference type!"); return MakeNaturalAlignPointeeAddrLValue(RV.getScalarVal(), E->getType()); } LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) { // FIXME: This shouldn't require another copy. return EmitAggExprToLValue(E); } LValue CodeGenFunction::EmitCXXConstructLValue(const CXXConstructExpr *E) { assert(E->getType()->getAsCXXRecordDecl()->hasTrivialDestructor() && "binding l-value to type which needs a temporary"); AggValueSlot Slot = CreateAggTemp(E->getType()); EmitCXXConstructExpr(E, Slot); return MakeAddrLValue(Slot.getAddress(), E->getType(), AlignmentSource::Decl); } LValue CodeGenFunction::EmitCXXTypeidLValue(const CXXTypeidExpr *E) { return MakeNaturalAlignAddrLValue(EmitCXXTypeidExpr(E), E->getType()); } Address CodeGenFunction::EmitCXXUuidofExpr(const CXXUuidofExpr *E) { return Builder.CreateElementBitCast(CGM.GetAddrOfUuidDescriptor(E), ConvertType(E->getType())); } LValue CodeGenFunction::EmitCXXUuidofLValue(const CXXUuidofExpr *E) { return MakeAddrLValue(EmitCXXUuidofExpr(E), E->getType(), AlignmentSource::Decl); } LValue CodeGenFunction::EmitCXXBindTemporaryLValue(const CXXBindTemporaryExpr *E) { AggValueSlot Slot = CreateAggTemp(E->getType(), "temp.lvalue"); Slot.setExternallyDestructed(); EmitAggExpr(E->getSubExpr(), Slot); EmitCXXTemporary(E->getTemporary(), E->getType(), Slot.getAddress()); return MakeAddrLValue(Slot.getAddress(), E->getType(), AlignmentSource::Decl); } LValue CodeGenFunction::EmitLambdaLValue(const LambdaExpr *E) { AggValueSlot Slot = CreateAggTemp(E->getType(), "temp.lvalue"); EmitLambdaExpr(E, Slot); return MakeAddrLValue(Slot.getAddress(), E->getType(), AlignmentSource::Decl); } LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) { RValue RV = EmitObjCMessageExpr(E); if (!RV.isScalar()) return MakeAddrLValue(RV.getAggregateAddress(), E->getType(), AlignmentSource::Decl); assert(E->getMethodDecl()->getReturnType()->isReferenceType() && "Can't have a scalar return unless the return type is a " "reference type!"); return MakeNaturalAlignPointeeAddrLValue(RV.getScalarVal(), E->getType()); } LValue CodeGenFunction::EmitObjCSelectorLValue(const ObjCSelectorExpr *E) { Address V = CGM.getObjCRuntime().GetAddrOfSelector(*this, E->getSelector()); return MakeAddrLValue(V, E->getType(), AlignmentSource::Decl); } llvm::Value *CodeGenFunction::EmitIvarOffset(const ObjCInterfaceDecl *Interface, const ObjCIvarDecl *Ivar) { return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar); } LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy, llvm::Value *BaseValue, const ObjCIvarDecl *Ivar, unsigned CVRQualifiers) { return CGM.getObjCRuntime().EmitObjCValueForIvar(*this, ObjectTy, BaseValue, Ivar, CVRQualifiers); } LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) { // FIXME: A lot of the code below could be shared with EmitMemberExpr. llvm::Value *BaseValue = nullptr; const Expr *BaseExpr = E->getBase(); Qualifiers BaseQuals; QualType ObjectTy; if (E->isArrow()) { BaseValue = EmitScalarExpr(BaseExpr); ObjectTy = BaseExpr->getType()->getPointeeType(); BaseQuals = ObjectTy.getQualifiers(); } else { LValue BaseLV = EmitLValue(BaseExpr); BaseValue = BaseLV.getPointer(); ObjectTy = BaseExpr->getType(); BaseQuals = ObjectTy.getQualifiers(); } LValue LV = EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(), BaseQuals.getCVRQualifiers()); setObjCGCLValueClass(getContext(), E, LV); return LV; } LValue CodeGenFunction::EmitStmtExprLValue(const StmtExpr *E) { // Can only get l-value for message expression returning aggregate type RValue RV = EmitAnyExprToTemp(E); return MakeAddrLValue(RV.getAggregateAddress(), E->getType(), AlignmentSource::Decl); } RValue CodeGenFunction::EmitCall(QualType CalleeType, const CGCallee &OrigCallee, const CallExpr *E, ReturnValueSlot ReturnValue, llvm::Value *Chain) { // Get the actual function type. The callee type will always be a pointer to // function type or a block pointer type. assert(CalleeType->isFunctionPointerType() && "Call must have function pointer type!"); const Decl *TargetDecl = OrigCallee.getAbstractInfo().getCalleeDecl(); if (const FunctionDecl *FD = dyn_cast_or_null(TargetDecl)) // We can only guarantee that a function is called from the correct // context/function based on the appropriate target attributes, // so only check in the case where we have both always_inline and target // since otherwise we could be making a conditional call after a check for // the proper cpu features (and it won't cause code generation issues due to // function based code generation). if (TargetDecl->hasAttr() && TargetDecl->hasAttr()) checkTargetFeatures(E, FD); CalleeType = getContext().getCanonicalType(CalleeType); auto PointeeType = cast(CalleeType)->getPointeeType(); CGCallee Callee = OrigCallee; if (getLangOpts().CPlusPlus && SanOpts.has(SanitizerKind::Function) && (!TargetDecl || !isa(TargetDecl))) { if (llvm::Constant *PrefixSig = CGM.getTargetCodeGenInfo().getUBSanFunctionSignature(CGM)) { SanitizerScope SanScope(this); // Remove any (C++17) exception specifications, to allow calling e.g. a // noexcept function through a non-noexcept pointer. auto ProtoTy = getContext().getFunctionTypeWithExceptionSpec(PointeeType, EST_None); llvm::Constant *FTRTTIConst = CGM.GetAddrOfRTTIDescriptor(ProtoTy, /*ForEH=*/true); llvm::Type *PrefixStructTyElems[] = {PrefixSig->getType(), Int32Ty}; llvm::StructType *PrefixStructTy = llvm::StructType::get( CGM.getLLVMContext(), PrefixStructTyElems, /*isPacked=*/true); llvm::Value *CalleePtr = Callee.getFunctionPointer(); llvm::Value *CalleePrefixStruct = Builder.CreateBitCast( CalleePtr, llvm::PointerType::getUnqual(PrefixStructTy)); llvm::Value *CalleeSigPtr = Builder.CreateConstGEP2_32(PrefixStructTy, CalleePrefixStruct, 0, 0); llvm::Value *CalleeSig = Builder.CreateAlignedLoad(CalleeSigPtr, getIntAlign()); llvm::Value *CalleeSigMatch = Builder.CreateICmpEQ(CalleeSig, PrefixSig); llvm::BasicBlock *Cont = createBasicBlock("cont"); llvm::BasicBlock *TypeCheck = createBasicBlock("typecheck"); Builder.CreateCondBr(CalleeSigMatch, TypeCheck, Cont); EmitBlock(TypeCheck); llvm::Value *CalleeRTTIPtr = Builder.CreateConstGEP2_32(PrefixStructTy, CalleePrefixStruct, 0, 1); llvm::Value *CalleeRTTIEncoded = Builder.CreateAlignedLoad(CalleeRTTIPtr, getPointerAlign()); llvm::Value *CalleeRTTI = DecodeAddrUsedInPrologue(CalleePtr, CalleeRTTIEncoded); llvm::Value *CalleeRTTIMatch = Builder.CreateICmpEQ(CalleeRTTI, FTRTTIConst); llvm::Constant *StaticData[] = { EmitCheckSourceLocation(E->getLocStart()), EmitCheckTypeDescriptor(CalleeType) }; EmitCheck(std::make_pair(CalleeRTTIMatch, SanitizerKind::Function), SanitizerHandler::FunctionTypeMismatch, StaticData, CalleePtr); Builder.CreateBr(Cont); EmitBlock(Cont); } } const auto *FnType = cast(PointeeType); // If we are checking indirect calls and this call is indirect, check that the // function pointer is a member of the bit set for the function type. if (SanOpts.has(SanitizerKind::CFIICall) && (!TargetDecl || !isa(TargetDecl))) { SanitizerScope SanScope(this); EmitSanitizerStatReport(llvm::SanStat_CFI_ICall); llvm::Metadata *MD; if (CGM.getCodeGenOpts().SanitizeCfiICallGeneralizePointers) MD = CGM.CreateMetadataIdentifierGeneralized(QualType(FnType, 0)); else MD = CGM.CreateMetadataIdentifierForType(QualType(FnType, 0)); llvm::Value *TypeId = llvm::MetadataAsValue::get(getLLVMContext(), MD); llvm::Value *CalleePtr = Callee.getFunctionPointer(); llvm::Value *CastedCallee = Builder.CreateBitCast(CalleePtr, Int8PtrTy); llvm::Value *TypeTest = Builder.CreateCall( CGM.getIntrinsic(llvm::Intrinsic::type_test), {CastedCallee, TypeId}); auto CrossDsoTypeId = CGM.CreateCrossDsoCfiTypeId(MD); llvm::Constant *StaticData[] = { llvm::ConstantInt::get(Int8Ty, CFITCK_ICall), EmitCheckSourceLocation(E->getLocStart()), EmitCheckTypeDescriptor(QualType(FnType, 0)), }; if (CGM.getCodeGenOpts().SanitizeCfiCrossDso && CrossDsoTypeId) { EmitCfiSlowPathCheck(SanitizerKind::CFIICall, TypeTest, CrossDsoTypeId, CastedCallee, StaticData); } else { EmitCheck(std::make_pair(TypeTest, SanitizerKind::CFIICall), SanitizerHandler::CFICheckFail, StaticData, {CastedCallee, llvm::UndefValue::get(IntPtrTy)}); } } CallArgList Args; if (Chain) Args.add(RValue::get(Builder.CreateBitCast(Chain, CGM.VoidPtrTy)), CGM.getContext().VoidPtrTy); // C++17 requires that we evaluate arguments to a call using assignment syntax // right-to-left, and that we evaluate arguments to certain other operators // left-to-right. Note that we allow this to override the order dictated by // the calling convention on the MS ABI, which means that parameter // destruction order is not necessarily reverse construction order. // FIXME: Revisit this based on C++ committee response to unimplementability. EvaluationOrder Order = EvaluationOrder::Default; if (auto *OCE = dyn_cast(E)) { if (OCE->isAssignmentOp()) Order = EvaluationOrder::ForceRightToLeft; else { switch (OCE->getOperator()) { case OO_LessLess: case OO_GreaterGreater: case OO_AmpAmp: case OO_PipePipe: case OO_Comma: case OO_ArrowStar: Order = EvaluationOrder::ForceLeftToRight; break; default: break; } } } EmitCallArgs(Args, dyn_cast(FnType), E->arguments(), E->getDirectCallee(), /*ParamsToSkip*/ 0, Order); const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeFreeFunctionCall( Args, FnType, /*isChainCall=*/Chain); // C99 6.5.2.2p6: // If the expression that denotes the called function has a type // that does not include a prototype, [the default argument // promotions are performed]. If the number of arguments does not // equal the number of parameters, the behavior is undefined. If // the function is defined with a type that includes a prototype, // and either the prototype ends with an ellipsis (, ...) or the // types of the arguments after promotion are not compatible with // the types of the parameters, the behavior is undefined. If the // function is defined with a type that does not include a // prototype, and the types of the arguments after promotion are // not compatible with those of the parameters after promotion, // the behavior is undefined [except in some trivial cases]. // That is, in the general case, we should assume that a call // through an unprototyped function type works like a *non-variadic* // call. The way we make this work is to cast to the exact type // of the promoted arguments. // // Chain calls use this same code path to add the invisible chain parameter // to the function type. if (isa(FnType) || Chain) { llvm::Type *CalleeTy = getTypes().GetFunctionType(FnInfo); CalleeTy = CalleeTy->getPointerTo(); llvm::Value *CalleePtr = Callee.getFunctionPointer(); CalleePtr = Builder.CreateBitCast(CalleePtr, CalleeTy, "callee.knr.cast"); Callee.setFunctionPointer(CalleePtr); } return EmitCall(FnInfo, Callee, ReturnValue, Args, nullptr, E->getExprLoc()); } LValue CodeGenFunction:: EmitPointerToDataMemberBinaryExpr(const BinaryOperator *E) { Address BaseAddr = Address::invalid(); if (E->getOpcode() == BO_PtrMemI) { BaseAddr = EmitPointerWithAlignment(E->getLHS()); } else { BaseAddr = EmitLValue(E->getLHS()).getAddress(); } llvm::Value *OffsetV = EmitScalarExpr(E->getRHS()); const MemberPointerType *MPT = E->getRHS()->getType()->getAs(); LValueBaseInfo BaseInfo; TBAAAccessInfo TBAAInfo; Address MemberAddr = EmitCXXMemberDataPointerAddress(E, BaseAddr, OffsetV, MPT, &BaseInfo, &TBAAInfo); return MakeAddrLValue(MemberAddr, MPT->getPointeeType(), BaseInfo, TBAAInfo); } /// Given the address of a temporary variable, produce an r-value of /// its type. RValue CodeGenFunction::convertTempToRValue(Address addr, QualType type, SourceLocation loc) { LValue lvalue = MakeAddrLValue(addr, type, AlignmentSource::Decl); switch (getEvaluationKind(type)) { case TEK_Complex: return RValue::getComplex(EmitLoadOfComplex(lvalue, loc)); case TEK_Aggregate: return lvalue.asAggregateRValue(); case TEK_Scalar: return RValue::get(EmitLoadOfScalar(lvalue, loc)); } llvm_unreachable("bad evaluation kind"); } void CodeGenFunction::SetFPAccuracy(llvm::Value *Val, float Accuracy) { assert(Val->getType()->isFPOrFPVectorTy()); if (Accuracy == 0.0 || !isa(Val)) return; llvm::MDBuilder MDHelper(getLLVMContext()); llvm::MDNode *Node = MDHelper.createFPMath(Accuracy); cast(Val)->setMetadata(llvm::LLVMContext::MD_fpmath, Node); } namespace { struct LValueOrRValue { LValue LV; RValue RV; }; } static LValueOrRValue emitPseudoObjectExpr(CodeGenFunction &CGF, const PseudoObjectExpr *E, bool forLValue, AggValueSlot slot) { SmallVector opaques; // Find the result expression, if any. const Expr *resultExpr = E->getResultExpr(); LValueOrRValue result; for (PseudoObjectExpr::const_semantics_iterator i = E->semantics_begin(), e = E->semantics_end(); i != e; ++i) { const Expr *semantic = *i; // If this semantic expression is an opaque value, bind it // to the result of its source expression. if (const auto *ov = dyn_cast(semantic)) { // Skip unique OVEs. if (ov->isUnique()) { assert(ov != resultExpr && "A unique OVE cannot be used as the result expression"); continue; } // If this is the result expression, we may need to evaluate // directly into the slot. typedef CodeGenFunction::OpaqueValueMappingData OVMA; OVMA opaqueData; if (ov == resultExpr && ov->isRValue() && !forLValue && CodeGenFunction::hasAggregateEvaluationKind(ov->getType())) { CGF.EmitAggExpr(ov->getSourceExpr(), slot); LValue LV = CGF.MakeAddrLValue(slot.getAddress(), ov->getType(), AlignmentSource::Decl); opaqueData = OVMA::bind(CGF, ov, LV); result.RV = slot.asRValue(); // Otherwise, emit as normal. } else { opaqueData = OVMA::bind(CGF, ov, ov->getSourceExpr()); // If this is the result, also evaluate the result now. if (ov == resultExpr) { if (forLValue) result.LV = CGF.EmitLValue(ov); else result.RV = CGF.EmitAnyExpr(ov, slot); } } opaques.push_back(opaqueData); // Otherwise, if the expression is the result, evaluate it // and remember the result. } else if (semantic == resultExpr) { if (forLValue) result.LV = CGF.EmitLValue(semantic); else result.RV = CGF.EmitAnyExpr(semantic, slot); // Otherwise, evaluate the expression in an ignored context. } else { CGF.EmitIgnoredExpr(semantic); } } // Unbind all the opaques now. for (unsigned i = 0, e = opaques.size(); i != e; ++i) opaques[i].unbind(CGF); return result; } RValue CodeGenFunction::EmitPseudoObjectRValue(const PseudoObjectExpr *E, AggValueSlot slot) { return emitPseudoObjectExpr(*this, E, false, slot).RV; } LValue CodeGenFunction::EmitPseudoObjectLValue(const PseudoObjectExpr *E) { return emitPseudoObjectExpr(*this, E, true, AggValueSlot::ignored()).LV; }