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//===--- CGExpr.cpp - Emit LLVM Code from Expressions ---------------------===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// 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/Basic/Builtins.h"
#include "clang/Basic/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 <string>
using namespace clang;
using namespace CodeGen;
// Miscellaneous Helper Methods
llvm::Value *CodeGenFunction::EmitCastToVoidPtr(llvm::Value *value) {
unsigned addressSpace =
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);
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)
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 =
return CreateTempAlloca(Ty, Align, Name);
void CodeGenFunction::InitTempAlloca(Address Var, llvm::Value *Init) {
auto *Store = new llvm::StoreInst(Init, Var.getPointer());
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),
/// 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) {
if (const MemberPointerType *MPT = E->getType()->getAs<MemberPointerType>()) {
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,
/// 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.
/// 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);
case TEK_Aggregate: {
EmitAggExpr(E, AggValueSlot::forAddr(Location, Quals,
case TEK_Scalar: {
RValue RV = RValue::get(EmitScalarExpr(E, /*Ignore*/ false));
LValue LV = MakeAddrLValue(Location, E->getType());
EmitStoreThroughLValue(RV, LV);
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.
case Qualifiers::OCL_Autoreleasing:
// Nothing to do; cleaned up by an autorelease pool.
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.
case SD_Thread:
// FIXME: We should probably register a cleanup in this case.
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<VarDecl>(VD) && VD->hasAttr<ObjCPreciseLifetimeAttr>();
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);
CGF.pushLifetimeExtendedDestroy(CleanupKind, ReferenceTemporary,
*Destroy, CleanupKind & EHCleanup);
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<RecordType>()) {
// Get the destructor for the reference temporary.
auto *ClassDecl = cast<CXXRecordDecl>(RT->getDecl());
if (!ClassDecl->hasTrivialDestructor())
ReferenceTemporaryDtor = ClassDecl->getDestructor();
if (!ReferenceTemporaryDtor)
// Call the destructor for the temporary.
switch (M->getStorageDuration()) {
case SD_Static:
case SD_Thread: {
llvm::FunctionCallee CleanupFn;
llvm::Constant *CleanupArg;
if (E->getType()->isArrayType()) {
CleanupFn = CodeGenFunction(CGF.CGM).generateDestroyHelper(
ReferenceTemporary, E->getType(),
CodeGenFunction::destroyCXXObject, CGF.getLangOpts().Exceptions,
CleanupArg = llvm::Constant::getNullValue(CGF.Int8PtrTy);
} else {
CleanupFn = CGF.CGM.getAddrAndTypeOfCXXStructor(
GlobalDecl(ReferenceTemporaryDtor, Dtor_Complete));
CleanupArg = cast<llvm::Constant>(ReferenceTemporary.getPointer());
CGF, *cast<VarDecl>(M->getExtendingDecl()), CleanupFn, CleanupArg);
case SD_FullExpression:
CGF.pushDestroy(NormalAndEHCleanup, ReferenceTemporary, E->getType(),
case SD_Automatic:
ReferenceTemporary, E->getType(),
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,
CharUnits alignment = CGF.getContext().getTypeAlignInChars(Ty);
llvm::Constant *C = GV;
if (AS != LangAS::Default)
C = TCG.performAddrSpaceCast(
CGF.CGM, GV, AS, 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();
assert((!M->getExtendingDecl() || !isa<VarDecl>(M->getExtendingDecl()) ||
!cast<VarDecl>(M->getExtendingDecl())->isARCPseudoStrong()) &&
"Reference should never be pseudo-strong!");
// 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<llvm::GlobalVariable>(Object.getPointer())) {
Object = Address(llvm::ConstantExpr::getBitCast(Var,
// 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);
LValue RefTempDst = MakeAddrLValue(Object, M->getType(),
switch (getEvaluationKind(E->getType())) {
default: llvm_unreachable("expected scalar or aggregate expression");
case TEK_Scalar:
EmitScalarInit(E, M->getExtendingDecl(), RefTempDst, false);
case TEK_Aggregate: {
EmitAggExpr(E, AggValueSlot::forAddr(Object,
pushTemporaryCleanup(*this, M, E, Object);
return RefTempDst;
SmallVector<const Expr *, 2> CommaLHSs;
SmallVector<SubobjectAdjustment, 2> Adjustments;
E = E->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
for (const auto &Ignored : CommaLHSs)
if (const auto *opaque = dyn_cast<OpaqueValueExpr>(E)) {
if (opaque->getType()->isRecordType()) {
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<llvm::GlobalVariable>(
Object.getPointer()->stripPointerCasts())) {
Object = Address(llvm::ConstantExpr::getBitCast(
// 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()) {
EmitAnyExprToMem(E, Object, Qualifiers(), /*IsInit*/true);
} else {
switch (M->getStorageDuration()) {
case SD_Automatic:
if (auto *Size = EmitLifetimeStart(
Alloca.getPointer())) {
Alloca, Size);
case SD_FullExpression: {
if (!ShouldEmitLifetimeMarkers)
// Avoid creating a conditional cleanup just to hold an llvm.lifetime.end
// marker. Instead, start the lifetime of a conditional temporary earlier
// so that it's unconditional. Don't do this with sanitizers which need
// more precise lifetime marks.
ConditionalEvaluation *OldConditional = nullptr;
CGBuilderTy::InsertPoint OldIP;
if (isInConditionalBranch() && !E->getType().isDestructedType() &&
!SanOpts.has(SanitizerKind::HWAddress) &&
!SanOpts.has(SanitizerKind::Memory) &&
!CGM.getCodeGenOpts().SanitizeAddressUseAfterScope) {
OldConditional = OutermostConditional;
OutermostConditional = nullptr;
OldIP = Builder.saveIP();
llvm::BasicBlock *Block = OldConditional->getStartingBlock();
Block, llvm::BasicBlock::iterator(Block->back())));
if (auto *Size = EmitLifetimeStart(
Alloca.getPointer())) {
pushFullExprCleanup<CallLifetimeEnd>(NormalEHLifetimeMarker, Alloca,
if (OldConditional) {
OutermostConditional = OldConditional;
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,
/*NullCheckValue=*/ false, E->getExprLoc());
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();
case SubobjectAdjustment::MemberPointerAdjustment: {
llvm::Value *Ptr = EmitScalarExpr(Adjustment.Ptr.RHS);
Object = EmitCXXMemberDataPointerAddress(E, Object, Ptr,
return MakeAddrLValue(Object, M->getType(), AlignmentSource::Decl);
CodeGenFunction::EmitReferenceBindingToExpr(const Expr *E) {
// Emit the expression as an lvalue.
LValue LV = EmitLValue(E);
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<llvm::ConstantInt>(Elts->getAggregateElement(Idx))
/// 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) |
void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc,
llvm::Value *Ptr, QualType Ty,
CharUnits Alignment,
SanitizerSet SkippedChecks,
llvm::Value *ArraySize) {
if (!sanitizePerformTypeCheck())
// 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())
// Don't check pointers to volatile data. The behavior here is implementation-
// defined.
if (Ty.isVolatileQualified())
SanitizerScope SanScope(this);
SmallVector<std::pair<llvm::Value *, SanitizerMask>, 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<llvm::AllocaInst>(Ptr->stripPointerCasts());
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);
} else {
Checks.push_back(std::make_pair(IsNonNull, SanitizerKind::Null));
if (SanOpts.has(SanitizerKind::ObjectSize) &&
!SkippedChecks.has(SanitizerKind::ObjectSize) &&
!Ty->isIncompleteType()) {
uint64_t TySize = getContext().getTypeSizeInChars(Ty).getQuantity();
llvm::Value *Size = llvm::ConstantInt::get(IntPtrTy, TySize);
if (ArraySize)
Size = Builder.CreateMul(Size, ArraySize);
// Degenerate case: new X[0] does not need an objectsize check.
llvm::Constant *ConstantSize = dyn_cast<llvm::Constant>(Size);
if (!ConstantSize || !ConstantSize->isNullValue()) {
// 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::Function *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, Tys);
llvm::Value *Min = Builder.getFalse();
llvm::Value *NullIsUnknown = Builder.getFalse();
llvm::Value *Dynamic = Builder.getFalse();
llvm::Value *CastAddr = Builder.CreateBitCast(Ptr, Int8PtrTy);
llvm::Value *LargeEnough = Builder.CreateICmpUGE(
Builder.CreateCall(F, {CastAddr, Min, NullIsUnknown, Dynamic}), 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 []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);
// 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);
// 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,
llvm::Value *Slot = Builder.CreateAnd(Hash,
llvm::Value *Indices[] = { Builder.getInt32(0), Slot };
llvm::Value *CacheVal =
Builder.CreateAlignedLoad(Builder.CreateInBoundsGEP(Cache, Indices),
// 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[] = {
llvm::ConstantInt::get(Int8Ty, TCK)
llvm::Value *DynamicData[] = { Ptr, Hash };
EmitCheck(std::make_pair(EqualHash, SanitizerKind::Vptr),
SanitizerHandler::DynamicTypeCacheMiss, StaticData,
if (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<ConstantArrayType>(AT)) {
if (CAT->getSize().ugt(1))
return false;
} else if (!isa<IncompleteArrayType>(AT))
return false;
E = E->IgnoreParens();
// A flexible array member must be the last member in the class.
if (const auto *ME = dyn_cast<MemberExpr>(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<FieldDecl>(ME->getMemberDecl())) {
RecordDecl::field_iterator FI(
DeclContext::decl_iterator(const_cast<FieldDecl *>(FD)));
return ++FI == FD->getParent()->field_end();
} else if (const auto *IRE = dyn_cast<ObjCIvarRefExpr>(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<DeclRefExpr>(E->IgnoreParenImpCasts());
if (!ArrayDeclRef)
return nullptr;
auto *ParamDecl = dyn_cast<ParmVarDecl>(ArrayDeclRef->getDecl());
if (!ParamDecl)
return nullptr;
auto *POSAttr = ParamDecl->getAttr<PassObjectSizeAttr>();
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<VectorType>()) {
IndexedType = Base->getType();
return CGF.Builder.getInt32(VT->getNumElements());
Base = Base->IgnoreParens();
if (const auto *CE = dyn_cast<CastExpr>(Base)) {
if (CE->getCastKind() == CK_ArrayToPointerDecay &&
!isFlexibleArrayMemberExpr(CE->getSubExpr())) {
IndexedType = CE->getSubExpr()->getType();
const ArrayType *AT = IndexedType->castAsArrayTypeUnsafe();
if (const auto *CAT = dyn_cast<ConstantArrayType>(AT))
return CGF.Builder.getInt(CAT->getSize());
else if (const auto *VAT = dyn_cast<VariableArrayType>(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)
bool IndexSigned = IndexType->isSignedIntegerOrEnumerationType();
llvm::Value *IndexVal = Builder.CreateIntCast(Index, SizeTy, IndexSigned);
llvm::Value *BoundVal = Builder.CreateIntCast(Bound, SizeTy, false);
llvm::Constant *StaticData[] = {
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<llvm::IntegerType>(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()->castAs<ComplexType>()->getElementType();
llvm::APFloat FVal(getContext().getFloatTypeSemantics(ElemTy), 1);
if (!isInc)
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())
if (CGDebugInfo *DI = getModuleDebugInfo())
// 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 = E->IgnoreParens();
// Casts:
if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
if (const auto *ECE = dyn_cast<ExplicitCastExpr>(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<PointerType>()) {
if (PtrTy->getPointeeType()->isVoidType())
LValueBaseInfo InnerBaseInfo;
TBAAAccessInfo InnerTBAAInfo;
Address Addr = EmitPointerWithAlignment(CE->getSubExpr(),
if (BaseInfo) *BaseInfo = InnerBaseInfo;
if (TBAAInfo) *TBAAInfo = InnerTBAAInfo;
if (isa<ExplicitCastExpr>(CE)) {
LValueBaseInfo TargetTypeBaseInfo;
TBAAAccessInfo TargetTypeTBAAInfo;
CharUnits Align = getNaturalPointeeTypeAlignment(E->getType(),
if (TBAAInfo)
*TBAAInfo = CGM.mergeTBAAInfoForCast(*TBAAInfo,
// If the source l-value is opaque, honor the alignment of the
// casted-to type.
if (InnerBaseInfo.getAlignmentSource() != AlignmentSource::Decl) {
if (BaseInfo)
Addr = Address(Addr.getPointer(), Align);
if (SanOpts.has(SanitizerKind::CFIUnrelatedCast) &&
CE->getCastKind() == CK_BitCast) {
if (auto PT = E->getType()->getAs<PointerType>())
EmitVTablePtrCheckForCast(PT->getPointeeType(), Addr.getPointer(),
return CE->getCastKind() != CK_AddressSpaceConversion
? Builder.CreateBitCast(Addr, ConvertType(E->getType()))
: Builder.CreateAddrSpaceCast(Addr,
// 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(),
// TODO: Is there any reason to treat base-to-derived conversions
// specially?
// Unary &.
if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(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,
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 =
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()),
bool CodeGenFunction::IsWrappedCXXThis(const Expr *Obj) {
const Expr *Base = Obj;
while (!isa<CXXThisExpr>(Base)) {
// The result of a dynamic_cast can be null.
if (isa<CXXDynamicCastExpr>(Base))
return false;
if (const auto *CE = dyn_cast<CastExpr>(Base)) {
Base = CE->getSubExpr();
} else if (const auto *PE = dyn_cast<ParenExpr>(Base)) {
Base = PE->getSubExpr();
} else if (const auto *UO = dyn_cast<UnaryOperator>(Base)) {
if (UO->getOpcode() == UO_Extension)
Base = UO->getSubExpr();
return false;
} else {
return false;
return true;
LValue CodeGenFunction::EmitCheckedLValue(const Expr *E, TypeCheckKind TCK) {
LValue LV;
if (SanOpts.has(SanitizerKind::ArrayBounds) && isa<ArraySubscriptExpr>(E))
LV = EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E), /*Accessed*/true);
LV = EmitLValue(E);
if (!isa<DeclRefExpr>(E) && !LV.isBitField() && LV.isSimple()) {
SanitizerSet SkippedChecks;
if (const auto *ME = dyn_cast<MemberExpr>(E)) {
bool IsBaseCXXThis = IsWrappedCXXThis(ME->getBase());
if (IsBaseCXXThis)
SkippedChecks.set(SanitizerKind::Alignment, true);
if (IsBaseCXXThis || isa<DeclRefExpr>(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<ObjCSelectorExpr>(E));
case Expr::ObjCIsaExprClass:
return EmitObjCIsaExpr(cast<ObjCIsaExpr>(E));
case Expr::BinaryOperatorClass:
return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
case Expr::CompoundAssignOperatorClass: {
QualType Ty = E->getType();
if (const AtomicType *AT = Ty->getAs<AtomicType>())
Ty = AT->getValueType();
if (!Ty->isAnyComplexType())
return EmitCompoundAssignmentLValue(cast<CompoundAssignOperator>(E));
return EmitComplexCompoundAssignmentLValue(cast<CompoundAssignOperator>(E));
case Expr::CallExprClass:
case Expr::CXXMemberCallExprClass:
case Expr::CXXOperatorCallExprClass:
case Expr::UserDefinedLiteralClass:
return EmitCallExprLValue(cast<CallExpr>(E));
case Expr::VAArgExprClass:
return EmitVAArgExprLValue(cast<VAArgExpr>(E));
case Expr::DeclRefExprClass:
return EmitDeclRefLValue(cast<DeclRefExpr>(E));
case Expr::ConstantExprClass:
return EmitLValue(cast<ConstantExpr>(E)->getSubExpr());
case Expr::ParenExprClass:
return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
case Expr::GenericSelectionExprClass:
return EmitLValue(cast<GenericSelectionExpr>(E)->getResultExpr());
case Expr::PredefinedExprClass:
return EmitPredefinedLValue(cast<PredefinedExpr>(E));
case Expr::StringLiteralClass:
return EmitStringLiteralLValue(cast<StringLiteral>(E));
case Expr::ObjCEncodeExprClass:
return EmitObjCEncodeExprLValue(cast<ObjCEncodeExpr>(E));
case Expr::PseudoObjectExprClass:
return EmitPseudoObjectLValue(cast<PseudoObjectExpr>(E));
case Expr::InitListExprClass:
return EmitInitListLValue(cast<InitListExpr>(E));
case Expr::CXXTemporaryObjectExprClass:
case Expr::CXXConstructExprClass:
return EmitCXXConstructLValue(cast<CXXConstructExpr>(E));
case Expr::CXXBindTemporaryExprClass:
return EmitCXXBindTemporaryLValue(cast<CXXBindTemporaryExpr>(E));
case Expr::CXXUuidofExprClass:
return EmitCXXUuidofLValue(cast<CXXUuidofExpr>(E));
case Expr::LambdaExprClass:
return EmitAggExprToLValue(E);
case Expr::ExprWithCleanupsClass: {
const auto *cleanups = cast<ExprWithCleanups>(E);
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();
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: {
auto *DAE = cast<CXXDefaultArgExpr>(E);
CXXDefaultArgExprScope Scope(*this, DAE);
return EmitLValue(DAE->getExpr());
case Expr::CXXDefaultInitExprClass: {
auto *DIE = cast<CXXDefaultInitExpr>(E);
CXXDefaultInitExprScope Scope(*this, DIE);
return EmitLValue(DIE->getExpr());
case Expr::CXXTypeidExprClass:
return EmitCXXTypeidLValue(cast<CXXTypeidExpr>(E));
case Expr::ObjCMessageExprClass:
return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
case Expr::ObjCIvarRefExprClass:
return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
case Expr::StmtExprClass:
return EmitStmtExprLValue(cast<StmtExpr>(E));
case Expr::UnaryOperatorClass:
return EmitUnaryOpLValue(cast<UnaryOperator>(E));
case Expr::ArraySubscriptExprClass:
return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
case Expr::OMPArraySectionExprClass:
return EmitOMPArraySectionExpr(cast<OMPArraySectionExpr>(E));
case Expr::ExtVectorElementExprClass:
return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
case Expr::MemberExprClass:
return EmitMemberExpr(cast<MemberExpr>(E));
case Expr::CompoundLiteralExprClass:
return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
case Expr::ConditionalOperatorClass:
return EmitConditionalOperatorLValue(cast<ConditionalOperator>(E));
case Expr::BinaryConditionalOperatorClass:
return EmitConditionalOperatorLValue(cast<BinaryConditionalOperator>(E));
case Expr::ChooseExprClass:
return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr());
case Expr::OpaqueValueExprClass:
return EmitOpaqueValueLValue(cast<OpaqueValueExpr>(E));
case Expr::SubstNonTypeTemplateParmExprClass:
return EmitLValue(cast<SubstNonTypeTemplateParmExpr>(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<CastExpr>(E));
case Expr::MaterializeTemporaryExprClass:
return EmitMaterializeTemporaryExpr(cast<MaterializeTemporaryExpr>(E));
case Expr::CoawaitExprClass:
return EmitCoawaitLValue(cast<CoawaitExpr>(E));
case Expr::CoyieldExprClass:
return EmitCoyieldLValue(cast<CoyieldExpr>(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) {
// 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<RecordType>(type))
if (const auto *RD = dyn_cast<CXXRecordDecl>(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::mightBeUsableInConstantExpressions 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 {
static ConstantEmissionKind checkVarTypeForConstantEmission(QualType type) {
type = type.getCanonicalType();
if (const auto *ref = dyn_cast<ReferenceType>(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 just an optimization, but it avoids us needing
/// to emit global copies of variables if they're named without triggering
/// a formal use in a context where we can't emit a direct reference to them,
/// for instance if a block or lambda or a member of a local class uses a
/// const int variable or constexpr variable from an enclosing function.
CodeGenFunction::tryEmitAsConstant(DeclRefExpr *refExpr) {
ValueDecl *value = refExpr->getDecl();
// The value needs to be an enum constant or a constant variable.
ConstantEmissionKind CEK;
if (isa<ParmVarDecl>(value)) {
CEK = CEK_None;
} else if (auto *var = dyn_cast<VarDecl>(value)) {
CEK = checkVarTypeForConstantEmission(var->getType());
} else if (isa<EnumConstantDecl>(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<VarDecl>(value)) {
if (!getContext().DeclMustBeEmitted(cast<VarDecl>(value)))
EmitDeclRefExprDbgValue(refExpr, result.Val);
} else {
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<VarDecl>(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(), nullptr, nullptr, ME->isNonOdrUse());
return nullptr;
CodeGenFunction::tryEmitAsConstant(const MemberExpr *ME) {
if (DeclRefExpr *DRE = tryToConvertMemberExprToDeclRefExpr(*this, ME))
return tryEmitAsConstant(DRE);
return ConstantEmission();
llvm::Value *CodeGenFunction::emitScalarConstant(
const CodeGenFunction::ConstantEmission &Constant, Expr *E) {
assert(Constant && "not a constant");
if (Constant.isReference())
return EmitLoadOfLValue(Constant.getReferenceLValue(*this, E),
return Constant.getValue();
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<EnumType>())
return ET->getDecl()->getIntegerType()->isBooleanType();
if (const AtomicType *AT = Ty->getAs<AtomicType>())
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<EnumType>();
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,
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) ||
bool NeedsBoolCheck = HasBoolCheck && IsBool;
bool NeedsEnumCheck = HasEnumCheck && Ty->getAs<EnumType>();
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<llvm::IntegerType>(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;
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),
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<llvm::VectorType>(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<llvm::VectorType>(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),
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);
llvm::StoreInst *Store = Builder.CreateStore(Value, Addr, Volatile);
if (isNontemporal) {
llvm::MDNode *Node =
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,
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()) {
// Everything needs a load.
return RValue::get(EmitLoadOfScalar(LV, Loc));
if (LV.isVectorElt()) {
llvm::LoadInst *Load = Builder.CreateLoad(LV.getVectorAddress(),
return RValue::get(Builder.CreateExtractElement(Load, LV.getVectorIdx(),
// 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<unsigned>(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<unsigned>(Info.Offset) + Info.Size < Info.StorageSize)
Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(Info.StorageSize,
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(),
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<VectorType>();
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<llvm::Constant*, 4> 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()),
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<VectorType>();
QualType EQT = ExprVT->getElementType();
llvm::Type *VectorElementTy = CGM.getTypes().ConvertType(EQT);
Address CastToPointerElement =
Builder.CreateElementBitCast(VectorAddress, VectorElementTy,
const llvm::Constant *Elts = LV.getExtVectorElts();
unsigned ix = getAccessedFieldNo(0, Elts);
Address VectorBasePtrPlusIx =
Builder.CreateConstInBoundsGEP(CastToPointerElement, ix,
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<llvm::MDNode>(
// 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::Function *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(),
Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
Dst.getVectorIdx(), "vecins");
Builder.CreateStore(Vec, Dst.getVectorAddress(),
// 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
case Qualifiers::OCL_Strong:
if (isInit) {
Src = RValue::get(EmitARCRetain(Dst.getType(), Src.getScalarVal()));
EmitARCStoreStrong(Dst, Src.getScalarVal(), /*ignore*/ true);
case Qualifiers::OCL_Weak:
if (isInit)
// Initialize and then skip the primitive store.
EmitARCInitWeak(Dst.getAddress(), Src.getScalarVal());
EmitARCStoreWeak(Dst.getAddress(), Src.getScalarVal(), /*ignore*/ true);
case Qualifiers::OCL_Autoreleasing:
Src = RValue::get(EmitObjCExtendObjectLifetime(Dst.getType(),
// fall into the normal path
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);
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,
llvm::Value *BytesBetween = Builder.CreateSub(LHS, RHS, "ivar.offset");
CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, dst,
} else if (Dst.isGlobalObjCRef()) {
CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst,
CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
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(),
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,
MaskedVal = SrcVal;
if (Info.Offset)
SrcVal = Builder.CreateShl(SrcVal, Info.Offset, "bf.shl");
// Mask out the original value.
Val = Builder.CreateAnd(Val,
Info.Offset + Info.Size),
// 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,
*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(),
const llvm::Constant *Elts = Dst.getExtVectorElts();
llvm::Value *SrcVal = Src.getScalarVal();
if (const VectorType *VTy = Dst.getType()->getAs<VectorType>()) {
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<llvm::Constant*, 4> 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,
} 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<llvm::Constant*, 4> ExtMask;
for (unsigned i = 0; i != NumSrcElts; ++i)
ExtMask.resize(NumDstElts, llvm::UndefValue::get(Int32Ty));
llvm::Value *ExtMaskV = llvm::ConstantVector::get(ExtMask);
llvm::Value *ExtSrcVal =
// build identity
SmallVector<llvm::Constant*, 4> Mask;
for (unsigned i = 0; i != NumDstElts; ++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())
// 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(),
/// 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<llvm::MDNode>(
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::Function *F = CGM.getIntrinsic(llvm::Intrinsic::write_register, Types);
llvm::Value *Value = Src.getScalarVal();
if (OrigTy->isPointerTy())
Value = Builder.CreatePtrToInt(Value, Ty);
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)
if (isa<ObjCIvarRefExpr>(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->castAs<PointerType>()->getPointeeType();
if (ExpTy->isRecordType()) {
auto *Exp = cast<ObjCIvarRefExpr>(const_cast<Expr *>(E));
if (const auto *Exp = dyn_cast<DeclRefExpr>(E)) {
if (const auto *VD = dyn_cast<VarDecl>(Exp->getDecl())) {
if (VD->hasGlobalStorage()) {
LV.setThreadLocalRef(VD->getTLSKind() != VarDecl::TLS_None);
if (const auto *Exp = dyn_cast<UnaryOperator>(E)) {
setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
if (const auto *Exp = dyn_cast<ParenExpr>(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->castAs<PointerType>()->getPointeeType();
if (ExpTy->isRecordType())
if (const auto *Exp = dyn_cast<GenericSelectionExpr>(E)) {
setObjCGCLValueClass(Ctx, Exp->getResultExpr(), LV);
if (const auto *Exp = dyn_cast<ImplicitCastExpr>(E)) {
setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
if (const auto *Exp = dyn_cast<CStyleCastExpr>(E)) {
setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
if (const auto *Exp = dyn_cast<ObjCBridgedCastExpr>(E)) {
setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
if (const auto *Exp = dyn_cast<ArraySubscriptExpr>(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;
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;
if (const auto *Exp = dyn_cast<MemberExpr>(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().
static llvm::Value *
EmitBitCastOfLValueToProperType(CodeGenFunction &CGF,
llvm::Value *V, llvm::Type *IRType,
StringRef Name = StringRef()) {
unsigned AS = cast<llvm::PointerType>(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 emitDeclTargetVarDeclLValue(CodeGenFunction &CGF,
const VarDecl *VD, QualType T) {
llvm::Optional<OMPDeclareTargetDeclAttr::MapTypeTy> Res =
// Return an invalid address if variable is MT_To and unified
// memory is not enabled. For all other cases: MT_Link and
// MT_To with unified memory, return a valid address.
if (!Res || (*Res == OMPDeclareTargetDeclAttr::MT_To &&
return Address::invalid();
assert(((*Res == OMPDeclareTargetDeclAttr::MT_Link) ||
(*Res == OMPDeclareTargetDeclAttr::MT_To &&
CGF.CGM.getOpenMPRuntime().hasRequiresUnifiedSharedMemory())) &&
"Expected link clause OR to clause with unified memory enabled.");
QualType PtrTy = CGF.getContext().getPointerType(VD->getType());
Address Addr = CGF.CGM.getOpenMPRuntime().getAddrOfDeclareTargetVar(VD);
return CGF.EmitLoadOfPointer(Addr, PtrTy->castAs<PointerType>());
CodeGenFunction::EmitLoadOfReference(LValue RefLVal,
LValueBaseInfo *PointeeBaseInfo,
TBAAAccessInfo *PointeeTBAAInfo) {
llvm::LoadInst *Load = Builder.CreateLoad(RefLVal.getAddress(),
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,
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,
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 &&
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 = emitDeclTargetVarDeclLValue(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<OMPThreadPrivateDeclAttr>()) {
return EmitThreadPrivateVarDeclLValue(CGF, VD, T, Addr, RealVarTy,
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<WeakRefAttr>()) {
ConstantAddress aliasee = CGM.GetWeakRefReference(FD);
return aliasee.getPointer();
llvm::Constant *V = CGM.GetAddrOfFunction(FD);
if (!FD->hasPrototype()) {
if (const FunctionProtoType *Proto =
FD->getType()->getAs<FunctionProtoType>()) {
// 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 =
NoProtoType = CGM.getContext().getPointerType(NoProtoType);
V = llvm::ConstantExpr::getBitCast(V,
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,
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
/// 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<AsmLabelAttr>();
assert(Asm->getLabel().size() < 64-Name.size() &&
"Register name too big");
llvm::NamedMDNode *M =
if (M->getNumOperands() == 0) {
llvm::MDString *Str = llvm::MDString::get(CGM.getLLVMContext(),
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());
/// Determine whether we can emit a reference to \p VD from the current
/// context, despite not necessarily having seen an odr-use of the variable in
/// this context.
static bool canEmitSpuriousReferenceToVariable(CodeGenFunction &CGF,
const DeclRefExpr *E,
const VarDecl *VD,
bool IsConstant) {
// For a variable declared in an enclosing scope, do not emit a spurious
// reference even if we have a capture, as that will emit an unwarranted
// reference to our capture state, and will likely generate worse code than
// emitting a local copy.
if (E->refersToEnclosingVariableOrCapture())
return false;
// For a local declaration declared in this function, we can always reference
// it even if we don't have an odr-use.
if (VD->hasLocalStorage()) {
return VD->getDeclContext() ==
// For a global declaration, we can emit a reference to it if we know
// for sure that we are able to emit a definition of it.
VD = VD->getDefinition(CGF.getContext());
if (!VD)
return false;
// Don't emit a spurious reference if it might be to a variable that only
// exists on a different device / target.
// FIXME: This is unnecessarily broad. Check whether this would actually be a
// cross-target reference.
if (CGF.getLangOpts().OpenMP || CGF.getLangOpts().CUDA ||
CGF.getLangOpts().OpenCL) {
return false;
// We can emit a spurious reference only if the linkage implies that we'll
// be emitting a non-interposable symbol that will be retained until link
// time.
switch (CGF.CGM.getLLVMLinkageVarDefinition(VD, IsConstant)) {
case llvm::GlobalValue::ExternalLinkage:
case llvm::GlobalValue::LinkOnceODRLinkage:
case llvm::GlobalValue::WeakODRLinkage:
case llvm::GlobalValue::InternalLinkage:
case llvm::GlobalValue::PrivateLinkage:
return true;
return false;
LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
const NamedDecl *ND = E->getDecl();
QualType T = E->getType();
assert(E->isNonOdrUse() != NOUR_Unevaluated &&
"should not emit an unevaluated operand");
if (const auto *VD = dyn_cast<VarDecl>(ND)) {
// Global Named registers access via intrinsics only
if (VD->getStorageClass() == SC_Register &&
VD->hasAttr<AsmLabelAttr>() && !VD->isLocalVarDecl())
return EmitGlobalNamedRegister(VD, CGM);
// If this DeclRefExpr does not constitute an odr-use of the variable,
// we're not permitted to emit a reference to it in general, and it might
// not be captured if capture would be necessary for a use. Emit the
// constant value directly instead.
if (E->isNonOdrUse() == NOUR_Constant &&
(VD->getType()->isReferenceType() ||
!canEmitSpuriousReferenceToVariable(*this, E, VD, true))) {
llvm::Constant *Val = ConstantEmitter(*this).emitAbstract(
E->getLocation(), *VD->evaluateValue(), VD->getType());
assert(Val && "failed to emit constant expression");
Address Addr = Address::invalid();
if (!VD->getType()->isReferenceType()) {
// Spill the constant value to a global.
Addr = CGM.createUnnamedGlobalFrom(*VD, Val,
llvm::Type *VarTy = getTypes().ConvertTypeForMem(VD->getType());
auto *PTy = llvm::PointerType::get(
VarTy, getContext().getTargetAddressSpace(VD->getType()));
if (PTy != Addr.getType())
Addr = Builder.CreatePointerBitCastOrAddrSpaceCast(Addr, PTy);
} else {
// Should we be using the alignment of the constant pointer we emitted?
CharUnits Alignment =
/* BaseInfo= */ nullptr,
/* TBAAInfo= */ nullptr,
/* forPointeeType= */ true);
Addr = Address(Val, Alignment);
return MakeAddrLValue(Addr, T, AlignmentSource::Decl);
// FIXME: Handle other kinds of non-odr-use DeclRefExprs.