blob: 0f794487b922862840dd88052bd261ef3f687d89 [file] [log] [blame]
//===--- 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 "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "CGCall.h"
#include "CGCXXABI.h"
#include "CGDebugInfo.h"
#include "CGRecordLayout.h"
#include "CGObjCRuntime.h"
#include "TargetInfo.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclObjC.h"
#include "clang/Frontend/CodeGenOptions.h"
#include "llvm/Intrinsics.h"
#include "llvm/LLVMContext.h"
#include "llvm/Support/MDBuilder.h"
#include "llvm/Target/TargetData.h"
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.
llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(llvm::Type *Ty,
const Twine &Name) {
if (!Builder.isNamePreserving())
return new llvm::AllocaInst(Ty, 0, "", AllocaInsertPt);
return new llvm::AllocaInst(Ty, 0, Name, AllocaInsertPt);
void CodeGenFunction::InitTempAlloca(llvm::AllocaInst *Var,
llvm::Value *Init) {
llvm::StoreInst *Store = new llvm::StoreInst(Init, Var);
llvm::BasicBlock *Block = AllocaInsertPt->getParent();
Block->getInstList().insertAfter(&*AllocaInsertPt, Store);
llvm::AllocaInst *CodeGenFunction::CreateIRTemp(QualType Ty,
const Twine &Name) {
llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertType(Ty), Name);
// FIXME: Should we prefer the preferred type alignment here?
CharUnits Align = getContext().getTypeAlignInChars(Ty);
return Alloc;
llvm::AllocaInst *CodeGenFunction::CreateMemTemp(QualType Ty,
const Twine &Name) {
llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty), Name);
// FIXME: Should we prefer the preferred type alignment here?
CharUnits Align = getContext().getTypeAlignInChars(Ty);
return Alloc;
/// 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;
if (!E->getType()->isAnyComplexType())
return EmitScalarConversion(EmitScalarExpr(E), E->getType(), BoolTy);
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) {
if (!hasAggregateLLVMType(E->getType()))
return RValue::get(EmitScalarExpr(E, IgnoreResult));
else if (E->getType()->isAnyComplexType())
return RValue::getComplex(EmitComplexExpr(E, IgnoreResult, IgnoreResult));
EmitAggExpr(E, AggSlot, IgnoreResult);
return AggSlot.asRValue();
/// EmitAnyExprToTemp - Similary 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 (hasAggregateLLVMType(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,
llvm::Value *Location,
Qualifiers Quals,
bool IsInit) {
// FIXME: This function should take an LValue as an argument.
if (E->getType()->isAnyComplexType()) {
EmitComplexExprIntoAddr(E, Location, Quals.hasVolatile());
} else if (hasAggregateLLVMType(E->getType())) {
CharUnits Alignment = getContext().getTypeAlignInChars(E->getType());
EmitAggExpr(E, AggValueSlot::forAddr(Location, Alignment, Quals,
} else {
RValue RV = RValue::get(EmitScalarExpr(E, /*Ignore*/ false));
LValue LV = MakeAddrLValue(Location, E->getType());
EmitStoreThroughLValue(RV, LV);
namespace {
/// \brief An adjustment to be made to the temporary created when emitting a
/// reference binding, which accesses a particular subobject of that temporary.
struct SubobjectAdjustment {
enum {
} Kind;
union {
struct {
const CastExpr *BasePath;
const CXXRecordDecl *DerivedClass;
} DerivedToBase;
FieldDecl *Field;
struct {
const MemberPointerType *MPT;
llvm::Value *Ptr;
} Ptr;
SubobjectAdjustment(const CastExpr *BasePath,
const CXXRecordDecl *DerivedClass)
: Kind(DerivedToBaseAdjustment) {
DerivedToBase.BasePath = BasePath;
DerivedToBase.DerivedClass = DerivedClass;
SubobjectAdjustment(FieldDecl *Field)
: Kind(FieldAdjustment) {
this->Field = Field;
SubobjectAdjustment(const MemberPointerType *MPT, llvm::Value *Ptr)
: Kind(MemberPointerAdjustment) {
this->Ptr.MPT = MPT;
this->Ptr.Ptr = Ptr;
static llvm::Value *
CreateReferenceTemporary(CodeGenFunction &CGF, QualType Type,
const NamedDecl *InitializedDecl) {
if (const VarDecl *VD = dyn_cast_or_null<VarDecl>(InitializedDecl)) {
if (VD->hasGlobalStorage()) {
SmallString<256> Name;
llvm::raw_svector_ostream Out(Name);
CGF.CGM.getCXXABI().getMangleContext().mangleReferenceTemporary(VD, Out);
llvm::Type *RefTempTy = CGF.ConvertTypeForMem(Type);
// Create the reference temporary.
llvm::GlobalValue *RefTemp =
new llvm::GlobalVariable(CGF.CGM.getModule(),
RefTempTy, /*isConstant=*/false,
return RefTemp;
return CGF.CreateMemTemp(Type, "ref.tmp");
static llvm::Value *
EmitExprForReferenceBinding(CodeGenFunction &CGF, const Expr *E,
llvm::Value *&ReferenceTemporary,
const CXXDestructorDecl *&ReferenceTemporaryDtor,
QualType &ObjCARCReferenceLifetimeType,
const NamedDecl *InitializedDecl) {
// Look through single-element init lists that claim to be lvalues. They're
// just syntactic wrappers in this case.
if (const InitListExpr *ILE = dyn_cast<InitListExpr>(E)) {
if (ILE->getNumInits() == 1 && ILE->isGLValue())
E = ILE->getInit(0);
// Look through expressions for materialized temporaries (for now).
if (const MaterializeTemporaryExpr *M
= dyn_cast<MaterializeTemporaryExpr>(E)) {
// 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.
if (CGF.getContext().getLangOpts().ObjCAutoRefCount &&
E->getType()->isObjCLifetimeType() &&
(E->getType().getObjCLifetime() == Qualifiers::OCL_Strong ||
E->getType().getObjCLifetime() == Qualifiers::OCL_Weak ||
E->getType().getObjCLifetime() == Qualifiers::OCL_Autoreleasing))
ObjCARCReferenceLifetimeType = E->getType();
E = M->GetTemporaryExpr();
if (const CXXDefaultArgExpr *DAE = dyn_cast<CXXDefaultArgExpr>(E))
E = DAE->getExpr();
if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(E)) {
CodeGenFunction::RunCleanupsScope Scope(CGF);
return EmitExprForReferenceBinding(CGF, EWC->getSubExpr(),
RValue RV;
if (E->isGLValue()) {
// Emit the expression as an lvalue.
LValue LV = CGF.EmitLValue(E);
if (LV.isSimple())
return LV.getAddress();
// We have to load the lvalue.
RV = CGF.EmitLoadOfLValue(LV);
} else {
if (!ObjCARCReferenceLifetimeType.isNull()) {
ReferenceTemporary = CreateReferenceTemporary(CGF,
LValue RefTempDst = CGF.MakeAddrLValue(ReferenceTemporary,
CGF.EmitScalarInit(E, dyn_cast_or_null<ValueDecl>(InitializedDecl),
RefTempDst, false);
bool ExtendsLifeOfTemporary = false;
if (const VarDecl *Var = dyn_cast_or_null<VarDecl>(InitializedDecl)) {
if (Var->extendsLifetimeOfTemporary())
ExtendsLifeOfTemporary = true;
} else if (InitializedDecl && isa<FieldDecl>(InitializedDecl)) {
ExtendsLifeOfTemporary = true;
if (!ExtendsLifeOfTemporary) {
// Since the lifetime of this temporary isn't going to be extended,
// we need to clean it up ourselves at the end of the full expression.
switch (ObjCARCReferenceLifetimeType.getObjCLifetime()) {
case Qualifiers::OCL_None:
case Qualifiers::OCL_ExplicitNone:
case Qualifiers::OCL_Autoreleasing:
case Qualifiers::OCL_Strong: {
CleanupKind cleanupKind = CGF.getARCCleanupKind();
cleanupKind & EHCleanup);
case Qualifiers::OCL_Weak:
/*useEHCleanupForArray*/ true);
ObjCARCReferenceLifetimeType = QualType();
return ReferenceTemporary;
SmallVector<SubobjectAdjustment, 2> Adjustments;
while (true) {
E = E->IgnoreParens();
if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
if ((CE->getCastKind() == CK_DerivedToBase ||
CE->getCastKind() == CK_UncheckedDerivedToBase) &&
E->getType()->isRecordType()) {
E = CE->getSubExpr();
CXXRecordDecl *Derived
= cast<CXXRecordDecl>(E->getType()->getAs<RecordType>()->getDecl());
Adjustments.push_back(SubobjectAdjustment(CE, Derived));
if (CE->getCastKind() == CK_NoOp) {
E = CE->getSubExpr();
} else if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
if (!ME->isArrow() && ME->getBase()->isRValue()) {
if (FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
E = ME->getBase();
} else if (const BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
if (BO->isPtrMemOp()) {
E = BO->getLHS();
const MemberPointerType *MPT =
llvm::Value *Ptr = CGF.EmitScalarExpr(BO->getRHS());
Adjustments.push_back(SubobjectAdjustment(MPT, Ptr));
if (const OpaqueValueExpr *opaque = dyn_cast<OpaqueValueExpr>(E))
if (opaque->getType()->isRecordType())
return CGF.EmitOpaqueValueLValue(opaque).getAddress();
// Nothing changed.
// Create a reference temporary if necessary.
AggValueSlot AggSlot = AggValueSlot::ignored();
if (CGF.hasAggregateLLVMType(E->getType()) &&
!E->getType()->isAnyComplexType()) {
ReferenceTemporary = CreateReferenceTemporary(CGF, E->getType(),
CharUnits Alignment = CGF.getContext().getTypeAlignInChars(E->getType());
AggValueSlot::IsDestructed_t isDestructed
= AggValueSlot::IsDestructed_t(InitializedDecl != 0);
AggSlot = AggValueSlot::forAddr(ReferenceTemporary, Alignment,
Qualifiers(), isDestructed,
if (InitializedDecl) {
// Get the destructor for the reference temporary.
if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(RT->getDecl());
if (!ClassDecl->hasTrivialDestructor())
ReferenceTemporaryDtor = ClassDecl->getDestructor();
RV = CGF.EmitAnyExpr(E, AggSlot);
// Check if need to 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.
if (!Adjustments.empty()) {
llvm::Value *Object = RV.getAggregateAddr();
for (unsigned I = Adjustments.size(); I != 0; --I) {
SubobjectAdjustment &Adjustment = Adjustments[I-1];
switch (Adjustment.Kind) {
case SubobjectAdjustment::DerivedToBaseAdjustment:
Object =
case SubobjectAdjustment::FieldAdjustment: {
LValue LV = CGF.MakeAddrLValue(Object, E->getType());
LV = CGF.EmitLValueForField(LV, Adjustment.Field);
if (LV.isSimple()) {
Object = LV.getAddress();
// For non-simple lvalues, we actually have to create a copy of
// the object we're binding to.
QualType T = Adjustment.Field->getType().getNonReferenceType()
Object = CreateReferenceTemporary(CGF, T, InitializedDecl);
LValue TempLV = CGF.MakeAddrLValue(Object,
CGF.EmitStoreThroughLValue(CGF.EmitLoadOfLValue(LV), TempLV);
case SubobjectAdjustment::MemberPointerAdjustment: {
Object = CGF.CGM.getCXXABI().EmitMemberDataPointerAddress(
CGF, Object, Adjustment.Ptr.Ptr, Adjustment.Ptr.MPT);
return Object;
if (RV.isAggregate())
return RV.getAggregateAddr();
// Create a temporary variable that we can bind the reference to.
ReferenceTemporary = CreateReferenceTemporary(CGF, E->getType(),
unsigned Alignment =
if (RV.isScalar())
CGF.EmitStoreOfScalar(RV.getScalarVal(), ReferenceTemporary,
/*Volatile=*/false, Alignment, E->getType());
CGF.StoreComplexToAddr(RV.getComplexVal(), ReferenceTemporary,
return ReferenceTemporary;
CodeGenFunction::EmitReferenceBindingToExpr(const Expr *E,
const NamedDecl *InitializedDecl) {
llvm::Value *ReferenceTemporary = 0;
const CXXDestructorDecl *ReferenceTemporaryDtor = 0;
QualType ObjCARCReferenceLifetimeType;
llvm::Value *Value = EmitExprForReferenceBinding(*this, E, ReferenceTemporary,
if (!ReferenceTemporaryDtor && ObjCARCReferenceLifetimeType.isNull())
return RValue::get(Value);
// Make sure to call the destructor for the reference temporary.
const VarDecl *VD = dyn_cast_or_null<VarDecl>(InitializedDecl);
if (VD && VD->hasGlobalStorage()) {
if (ReferenceTemporaryDtor) {
llvm::Constant *DtorFn =
CGM.GetAddrOfCXXDestructor(ReferenceTemporaryDtor, Dtor_Complete);
CGM.getCXXABI().registerGlobalDtor(*this, DtorFn,
} else {
// Note: We intentionally do not register a global "destructor" to
// release the object.
return RValue::get(Value);
if (ReferenceTemporaryDtor)
PushDestructorCleanup(ReferenceTemporaryDtor, ReferenceTemporary);
else {
switch (ObjCARCReferenceLifetimeType.getObjCLifetime()) {
case Qualifiers::OCL_None:
"Not a reference temporary that needs to be deallocated");
case Qualifiers::OCL_ExplicitNone:
case Qualifiers::OCL_Autoreleasing:
// Nothing to do.
case Qualifiers::OCL_Strong: {
bool precise = VD && VD->hasAttr<ObjCPreciseLifetimeAttr>();
CleanupKind cleanupKind = getARCCleanupKind();
pushDestroy(cleanupKind, ReferenceTemporary, ObjCARCReferenceLifetimeType,
precise ? destroyARCStrongPrecise : destroyARCStrongImprecise,
cleanupKind & EHCleanup);
case Qualifiers::OCL_Weak: {
// __weak objects always get EH cleanups; otherwise, exceptions
// could cause really nasty crashes instead of mere leaks.
pushDestroy(NormalAndEHCleanup, ReferenceTemporary,
ObjCARCReferenceLifetimeType, destroyARCWeak, true);
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))
void CodeGenFunction::EmitCheck(llvm::Value *Address, unsigned Size) {
if (!CatchUndefined)
// This needs to be to the standard address space.
Address = Builder.CreateBitCast(Address, Int8PtrTy);
llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, IntPtrTy);
llvm::Value *Min = Builder.getFalse();
llvm::Value *C = Builder.CreateCall2(F, Address, Min);
llvm::BasicBlock *Cont = createBasicBlock();
llvm::ConstantInt::get(IntPtrTy, Size)),
Cont, getTrapBB());
CodeGenFunction::ComplexPairTy CodeGenFunction::
EmitComplexPrePostIncDec(const UnaryOperator *E, LValue LV,
bool isInc, bool isPre) {
ComplexPairTy InVal = LoadComplexFromAddr(LV.getAddress(),
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()->getAs<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.
StoreComplexToAddr(IncVal, LV.getAddress(), LV.isVolatileQualified());
// If this is a postinc, return the value read from memory, otherwise use the
// updated value.
return isPre ? IncVal : InVal;
// LValue Expression Emission
RValue CodeGenFunction::GetUndefRValue(QualType Ty) {
if (Ty->isVoidType())
return RValue::get(0);
if (const ComplexType *CTy = Ty->getAs<ComplexType>()) {
llvm::Type *EltTy = ConvertType(CTy->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.
if (hasAggregateLLVMType(Ty)) {
llvm::Value *DestPtr = CreateMemTemp(Ty, "undef.agg.tmp");
return RValue::getAggregate(DestPtr);
return RValue::get(llvm::UndefValue::get(ConvertType(Ty)));
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(llvm::UndefValue::get(Ty), E->getType());
LValue CodeGenFunction::EmitCheckedLValue(const Expr *E) {
LValue LV = EmitLValue(E);
if (!isa<DeclRefExpr>(E) && !LV.isBitField() && LV.isSimple())
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) {
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:
if (!E->getType()->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::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::LambdaExprClass:
return EmitLambdaLValue(cast<LambdaExpr>(E));
case Expr::ExprWithCleanupsClass: {
const ExprWithCleanups *cleanups = cast<ExprWithCleanups>(E);
RunCleanupsScope Scope(*this);
return EmitLValue(cleanups->getSubExpr());
case Expr::CXXScalarValueInitExprClass:
return EmitNullInitializationLValue(cast<CXXScalarValueInitExpr>(E));
case Expr::CXXDefaultArgExprClass:
return EmitLValue(cast<CXXDefaultArgExpr>(E)->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::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(getContext()));
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));
/// 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 RecordType *RT = dyn_cast<RecordType>(type))
if (const CXXRecordDecl *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::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 {
static ConstantEmissionKind checkVarTypeForConstantEmission(QualType type) {
type = type.getCanonicalType();
if (const ReferenceType *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 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::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 (VarDecl *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.
llvm::Constant *C = CGM.EmitConstantValue(result.Val, resultType, this);
// 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, C);
} else {
EmitDeclRefExprDbgValue(refExpr, C);
// If we emitted a reference constant, we need to dereference that.
if (resultIsReference)
return ConstantEmission::forReference(C);
return ConstantEmission::forValue(C);
llvm::Value *CodeGenFunction::EmitLoadOfScalar(LValue lvalue) {
return EmitLoadOfScalar(lvalue.getAddress(), lvalue.isVolatile(),
lvalue.getType(), lvalue.getTBAAInfo());
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;
llvm::MDNode *CodeGenFunction::getRangeForLoadFromType(QualType Ty) {
const EnumType *ET = Ty->getAs<EnumType>();
bool IsRegularCPlusPlusEnum = (getLangOpts().CPlusPlus && ET &&
CGM.getCodeGenOpts().StrictEnums &&
bool IsBool = hasBooleanRepresentation(Ty);
if (!IsBool && !IsRegularCPlusPlusEnum)
return NULL;
llvm::APInt Min;
llvm::APInt End;
if (IsBool) {
Min = llvm::APInt(8, 0);
End = llvm::APInt(8, 2);
} else {
const EnumDecl *ED = ET->getDecl();
llvm::Type *LTy = 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);
llvm::MDBuilder MDHelper(getLLVMContext());
return MDHelper.createRange(Min, End);
llvm::Value *CodeGenFunction::EmitLoadOfScalar(llvm::Value *Addr, bool Volatile,
unsigned Alignment, QualType Ty,
llvm::MDNode *TBAAInfo) {
llvm::LoadInst *Load = Builder.CreateLoad(Addr);
if (Volatile)
if (Alignment)
if (TBAAInfo)
CGM.DecorateInstruction(Load, TBAAInfo);
// If this is an atomic type, all normal reads must be atomic
if (Ty->isAtomicType())
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, Builder.getInt8Ty(), "frombool");
assert(Value->getType()->isIntegerTy(8) && "value rep of bool not i1/i8");
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(8) && "memory rep of bool not i8");
return Builder.CreateTrunc(Value, Builder.getInt1Ty(), "tobool");
return Value;
void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, llvm::Value *Addr,
bool Volatile, unsigned Alignment,
QualType Ty,
llvm::MDNode *TBAAInfo,
bool isInit) {
Value = EmitToMemory(Value, Ty);
llvm::StoreInst *Store = Builder.CreateStore(Value, Addr, Volatile);
if (Alignment)
if (TBAAInfo)
CGM.DecorateInstruction(Store, TBAAInfo);
if (!isInit && Ty->isAtomicType())
void CodeGenFunction::EmitStoreOfScalar(llvm::Value *value, LValue lvalue,
bool isInit) {
EmitStoreOfScalar(value, lvalue.getAddress(), lvalue.isVolatile(),
lvalue.getAlignment().getQuantity(), lvalue.getType(),
lvalue.getTBAAInfo(), isInit);
/// 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) {
if (LV.isObjCWeak()) {
// load of a __weak object.
llvm::Value *AddrWeakObj = LV.getAddress();
return RValue::get(CGM.getObjCRuntime().EmitObjCWeakRead(*this,
if (LV.getQuals().getObjCLifetime() == Qualifiers::OCL_Weak)
return RValue::get(EmitARCLoadWeak(LV.getAddress()));
if (LV.isSimple()) {
// Everything needs a load.
return RValue::get(EmitLoadOfScalar(LV));
if (LV.isVectorElt()) {
llvm::LoadInst *Load = Builder.CreateLoad(LV.getVectorAddr(),
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);
assert(LV.isBitField() && "Unknown LValue type!");
return EmitLoadOfBitfieldLValue(LV);
RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV) {
const CGBitFieldInfo &Info = LV.getBitFieldInfo();
// Get the output type.
llvm::Type *ResLTy = ConvertType(LV.getType());
unsigned ResSizeInBits = CGM.getTargetData().getTypeSizeInBits(ResLTy);
// Compute the result as an OR of all of the individual component accesses.
llvm::Value *Res = 0;
for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) {
const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i);
// Get the field pointer.
llvm::Value *Ptr = LV.getBitFieldBaseAddr();
// Only offset by the field index if used, so that incoming values are not
// required to be structures.
if (AI.FieldIndex)
Ptr = Builder.CreateStructGEP(Ptr, AI.FieldIndex, "bf.field");
// Offset by the byte offset, if used.
if (!AI.FieldByteOffset.isZero()) {
Ptr = EmitCastToVoidPtr(Ptr);
Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset.getQuantity(),
// Cast to the access type.
llvm::Type *PTy = llvm::Type::getIntNPtrTy(getLLVMContext(), AI.AccessWidth,
Ptr = Builder.CreateBitCast(Ptr, PTy);
// Perform the load.
llvm::LoadInst *Load = Builder.CreateLoad(Ptr, LV.isVolatileQualified());
if (!AI.AccessAlignment.isZero())
// Shift out unused low bits and mask out unused high bits.
llvm::Value *Val = Load;
if (AI.FieldBitStart)
Val = Builder.CreateLShr(Load, AI.FieldBitStart);
Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(AI.AccessWidth,
// Extend or truncate to the target size.
if (AI.AccessWidth < ResSizeInBits)
Val = Builder.CreateZExt(Val, ResLTy);
else if (AI.AccessWidth > ResSizeInBits)
Val = Builder.CreateTrunc(Val, ResLTy);
// Shift into place, and OR into the result.
if (AI.TargetBitOffset)
Val = Builder.CreateShl(Val, AI.TargetBitOffset);
Res = Res ? Builder.CreateOr(Res, Val) : Val;
// If the bit-field is signed, perform the sign-extension.
// FIXME: This can easily be folded into the load of the high bits, which
// could also eliminate the mask of high bits in some situations.
if (Info.isSigned()) {
unsigned ExtraBits = ResSizeInBits - Info.getSize();
if (ExtraBits)
Res = Builder.CreateAShr(Builder.CreateShl(Res, ExtraBits),
ExtraBits, "bf.val.sext");
return RValue::get(Res);
// If this is a reference to a subset of the elements of a vector, create an
// appropriate shufflevector.
RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV) {
llvm::LoadInst *Load = Builder.CreateLoad(LV.getExtVectorAddr(),
llvm::Value *Vec = Load;
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(Int32Ty, 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);
/// 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::LoadInst *Load = Builder.CreateLoad(Dst.getVectorAddr(),
llvm::Value *Vec = Load;
Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
Dst.getVectorIdx(), "vecins");
llvm::StoreInst *Store = Builder.CreateStore(Vec, Dst.getVectorAddr(),
// If this is an update of extended vector elements, insert them as
// appropriate.
if (Dst.isExtVectorElt())
return EmitStoreThroughExtVectorComponentLValue(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:
EmitARCStoreStrong(Dst, Src.getScalarVal(), /*ignore*/ true);
case Qualifiers::OCL_Weak:
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.
llvm::Value *LvalueDst = Dst.getAddress();
llvm::Value *src = Src.getScalarVal();
CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
if (Dst.isObjCStrong() && !Dst.isNonGC()) {
// load of a __strong object.
llvm::Value *LvalueDst = Dst.getAddress();
llvm::Value *src = Src.getScalarVal();
if (Dst.isObjCIvar()) {
assert(Dst.getBaseIvarExp() && "BaseIvarExp is NULL");
llvm::Type *ResultType = ConvertType(getContext().LongTy);
llvm::Value *RHS = EmitScalarExpr(Dst.getBaseIvarExp());
llvm::Value *dst = RHS;
RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
llvm::Value *LHS =
Builder.CreatePtrToInt(LvalueDst, ResultType, "sub.ptr.lhs.cast");
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();
// Get the output type.
llvm::Type *ResLTy = ConvertTypeForMem(Dst.getType());
unsigned ResSizeInBits = CGM.getTargetData().getTypeSizeInBits(ResLTy);
// Get the source value, truncated to the width of the bit-field.
llvm::Value *SrcVal = Src.getScalarVal();
if (hasBooleanRepresentation(Dst.getType()))
SrcVal = Builder.CreateIntCast(SrcVal, ResLTy, /*IsSigned=*/false);
SrcVal = Builder.CreateAnd(SrcVal, llvm::APInt::getLowBitsSet(ResSizeInBits,
// Return the new value of the bit-field, if requested.
if (Result) {
// Cast back to the proper type for result.
llvm::Type *SrcTy = Src.getScalarVal()->getType();
llvm::Value *ReloadVal = Builder.CreateIntCast(SrcVal, SrcTy, false,
// Sign extend if necessary.
if (Info.isSigned()) {
unsigned ExtraBits = ResSizeInBits - Info.getSize();
if (ExtraBits)
ReloadVal = Builder.CreateAShr(Builder.CreateShl(ReloadVal, ExtraBits),
ExtraBits, "bf.reload.sext");
*Result = ReloadVal;
// Iterate over the components, writing each piece to memory.
for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) {
const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i);
// Get the field pointer.
llvm::Value *Ptr = Dst.getBitFieldBaseAddr();
unsigned addressSpace =
// Only offset by the field index if used, so that incoming values are not
// required to be structures.
if (AI.FieldIndex)
Ptr = Builder.CreateStructGEP(Ptr, AI.FieldIndex, "bf.field");
// Offset by the byte offset, if used.
if (!AI.FieldByteOffset.isZero()) {
Ptr = EmitCastToVoidPtr(Ptr);
Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset.getQuantity(),
// Cast to the access type.
llvm::Type *AccessLTy =
llvm::Type::getIntNTy(getLLVMContext(), AI.AccessWidth);
llvm::Type *PTy = AccessLTy->getPointerTo(addressSpace);
Ptr = Builder.CreateBitCast(Ptr, PTy);
// Extract the piece of the bit-field value to write in this access, limited
// to the values that are part of this access.
llvm::Value *Val = SrcVal;
if (AI.TargetBitOffset)
Val = Builder.CreateLShr(Val, AI.TargetBitOffset);
Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(ResSizeInBits,
// Extend or truncate to the access size.
if (ResSizeInBits < AI.AccessWidth)
Val = Builder.CreateZExt(Val, AccessLTy);
else if (ResSizeInBits > AI.AccessWidth)
Val = Builder.CreateTrunc(Val, AccessLTy);
// Shift into the position in memory.
if (AI.FieldBitStart)
Val = Builder.CreateShl(Val, AI.FieldBitStart);
// If necessary, load and OR in bits that are outside of the bit-field.
if (AI.TargetBitWidth != AI.AccessWidth) {
llvm::LoadInst *Load = Builder.CreateLoad(Ptr, Dst.isVolatileQualified());
if (!AI.AccessAlignment.isZero())
// Compute the mask for zeroing the bits that are part of the bit-field.
llvm::APInt InvMask =
~llvm::APInt::getBitsSet(AI.AccessWidth, AI.FieldBitStart,
AI.FieldBitStart + AI.TargetBitWidth);
// Apply the mask and OR in to the value to write.
Val = Builder.CreateOr(Builder.CreateAnd(Load, InvMask), Val);
// Write the value.
llvm::StoreInst *Store = Builder.CreateStore(Val, Ptr,
if (!AI.AccessAlignment.isZero())
void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
LValue Dst) {
// This access turns into a read/modify/write of the vector. Load the input
// value now.
llvm::LoadInst *Load = Builder.CreateLoad(Dst.getExtVectorAddr(),
llvm::Value *Vec = Load;
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 =
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)
// 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(Int32Ty, InIdx);
Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt);
llvm::StoreInst *Store = Builder.CreateStore(Vec, Dst.getExtVectorAddr(),
// setObjCGCLValueClass - sets class of he 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->getAs<PointerType>()->getPointeeType();
if (ExpTy->isRecordType()) {
ObjCIvarRefExpr *Exp = cast<ObjCIvarRefExpr>(const_cast<Expr*>(E));
if (const DeclRefExpr *Exp = dyn_cast<DeclRefExpr>(E)) {
if (const VarDecl *VD = dyn_cast<VarDecl>(Exp->getDecl())) {
if (VD->hasGlobalStorage()) {
if (const UnaryOperator *Exp = dyn_cast<UnaryOperator>(E)) {
setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
if (const ParenExpr *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->getAs<PointerType>()->getPointeeType();
if (ExpTy->isRecordType())
if (const GenericSelectionExpr *Exp = dyn_cast<GenericSelectionExpr>(E)) {
setObjCGCLValueClass(Ctx, Exp->getResultExpr(), LV);
if (const ImplicitCastExpr *Exp = dyn_cast<ImplicitCastExpr>(E)) {
setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
if (const CStyleCastExpr *Exp = dyn_cast<CStyleCastExpr>(E)) {
setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
if (const ObjCBridgedCastExpr *Exp = dyn_cast<ObjCBridgedCastExpr>(E)) {
setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
if (const ArraySubscriptExpr *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 MemberExpr *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 EmitGlobalVarDeclLValue(CodeGenFunction &CGF,
const Expr *E, const VarDecl *VD) {
assert((VD->hasExternalStorage() || VD->isFileVarDecl()) &&
"Var decl must have external storage or be a file var 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);
QualType T = E->getType();
LValue LV;
if (VD->getType()->isReferenceType()) {
llvm::LoadInst *LI = CGF.Builder.CreateLoad(V);
V = LI;
LV = CGF.MakeNaturalAlignAddrLValue(V, T);
} else {
LV = CGF.MakeAddrLValue(V, E->getType(), Alignment);
setObjCGCLValueClass(CGF.getContext(), E, LV);
return LV;
static LValue EmitFunctionDeclLValue(CodeGenFunction &CGF,
const Expr *E, const FunctionDecl *FD) {
llvm::Value *V = CGF.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 = CGF.getContext().getPointerType(NoProtoType);
V = CGF.Builder.CreateBitCast(V, CGF.ConvertType(NoProtoType));
CharUnits Alignment = CGF.getContext().getDeclAlign(FD);
return CGF.MakeAddrLValue(V, E->getType(), Alignment);
LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
const NamedDecl *ND = E->getDecl();
CharUnits Alignment = getContext().getDeclAlign(ND);
QualType T = E->getType();
// 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<VarDecl>(ND) ||
!E->getLocation().isValid()) &&
"Should not use decl without marking it used!");
if (ND->hasAttr<WeakRefAttr>()) {
const ValueDecl *VD = cast<ValueDecl>(ND);
llvm::Constant *Aliasee = CGM.GetWeakRefReference(VD);
return MakeAddrLValue(Aliasee, E->getType(), Alignment);
if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
// Check if this is a global variable.
if (VD->hasExternalStorage() || VD->isFileVarDecl())
return EmitGlobalVarDeclLValue(*this, E, VD);
bool isBlockVariable = VD->hasAttr<BlocksAttr>();
bool NonGCable = VD->hasLocalStorage() &&
!VD->getType()->isReferenceType() &&
llvm::Value *V = LocalDeclMap[VD];
if (!V && VD->isStaticLocal())
V = CGM.getStaticLocalDeclAddress(VD);
// Use special handling for lambdas.
if (!V) {
if (FieldDecl *FD = LambdaCaptureFields.lookup(VD)) {
QualType LambdaTagType = getContext().getTagDeclType(FD->getParent());
LValue LambdaLV = MakeNaturalAlignAddrLValue(CXXABIThisValue,
return EmitLValueForField(LambdaLV, FD);
assert(isa<BlockDecl>(CurCodeDecl) && E->refersToEnclosingLocal());
CharUnits alignment = getContext().getDeclAlign(VD);
return MakeAddrLValue(GetAddrOfBlockDecl(VD, isBlockVariable),
E->getType(), alignment);
assert(V && "DeclRefExpr not entered in LocalDeclMap?");
if (isBlockVariable)
V = BuildBlockByrefAddress(V, VD);
LValue LV;
if (VD->getType()->isReferenceType()) {
llvm::LoadInst *LI = Builder.CreateLoad(V);
V = LI;
LV = MakeNaturalAlignAddrLValue(V, T);
} else {
LV = MakeAddrLValue(V, T, Alignment);
if (NonGCable) {
setObjCGCLValueClass(getContext(), E, LV);
return LV;
if (const FunctionDecl *fn = dyn_cast<FunctionDecl>(ND))
return EmitFunctionDeclLValue(*this, E, fn);
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");
LValue LV = MakeNaturalAlignAddrLValue(EmitScalarExpr(E->getSubExpr()), T);
// 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 (getContext().getLangOpts().ObjC1 &&
getContext().getLangOpts().getGC() != LangOptions::NonGC &&
return LV;
case UO_Real:
case UO_Imag: {
LValue LV = EmitLValue(E->getSubExpr());
assert(LV.isSimple() && "real/imag on non-ordinary l-value");
llvm::Value *Addr = LV.getAddress();
// __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 &&
->getElementType()->isStructTy()) {
return LV;
unsigned Idx = E->getOpcode() == UO_Imag;
return MakeAddrLValue(Builder.CreateStructGEP(LV.getAddress(),
Idx, "idx"),
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*/);
EmitScalarPrePostIncDec(E, LV, isInc, true/*isPre*/);
return LV;
LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
return MakeAddrLValue(CGM.GetAddrOfConstantStringFromLiteral(E),
LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
return MakeAddrLValue(CGM.GetAddrOfConstantStringFromObjCEncode(E),
LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
switch (E->getIdentType()) {
return EmitUnsupportedLValue(E, "predefined expression");
case PredefinedExpr::Func:
case PredefinedExpr::Function:
case PredefinedExpr::PrettyFunction: {
unsigned Type = E->getIdentType();
std::string GlobalVarName;
switch (Type) {
default: llvm_unreachable("Invalid type");
case PredefinedExpr::Func:
GlobalVarName = "__func__.";
case PredefinedExpr::Function:
GlobalVarName = "__FUNCTION__.";
case PredefinedExpr::PrettyFunction:
GlobalVarName = "__PRETTY_FUNCTION__.";
StringRef FnName = CurFn->getName();
if (FnName.startswith("\01"))
FnName = FnName.substr(1);
GlobalVarName += FnName;
const Decl *CurDecl = CurCodeDecl;
if (CurDecl == 0)
CurDecl = getContext().getTranslationUnitDecl();
std::string FunctionName =
? FnName.str()
: PredefinedExpr::ComputeName((PredefinedExpr::IdentType)Type, CurDecl));
llvm::Constant *C =
CGM.GetAddrOfConstantCString(FunctionName, GlobalVarName.c_str());
return MakeAddrLValue(C, E->getType());
llvm::BasicBlock *CodeGenFunction::getTrapBB() {
const CodeGenOptions &GCO = CGM.getCodeGenOpts();
// If we are not optimzing, don't collapse all calls to trap in the function
// to the same call, that way, in the debugger they can see which operation
// did in fact fail. If we are optimizing, we collapse all calls to trap down
// to just one per function to save on codesize.
if (GCO.OptimizationLevel && TrapBB)
return TrapBB;
llvm::BasicBlock *Cont = 0;
if (HaveInsertPoint()) {
Cont = createBasicBlock("cont");
TrapBB = createBasicBlock("trap");
llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::trap);
llvm::CallInst *TrapCall = Builder.CreateCall(F);
if (Cont)
return TrapBB;
/// 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 CastExpr *CE = dyn_cast<CastExpr>(E);
if (CE == 0 || CE->getCastKind() != CK_ArrayToPointerDecay)
return 0;
// If this is a decay from variable width array, bail out.
const Expr *SubExpr = CE->getSubExpr();
if (SubExpr->getType()->isVariableArrayType())
return 0;
return SubExpr;
LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
// The index must always be an integer, which is not an aggregate. Emit it.
llvm::Value *Idx = EmitScalarExpr(E->getIdx());
QualType IdxTy = E->getIdx()->getType();
bool IdxSigned = IdxTy->isSignedIntegerOrEnumerationType();
// If the base is a vector type, then we are forming a vector element lvalue
// with this subscript.
if (E->getBase()->getType()->isVectorType()) {
// Emit the vector as an lvalue to get its address.
LValue LHS = EmitLValue(E->getBase());
assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
Idx = Builder.CreateIntCast(Idx, Int32Ty, IdxSigned, "vidx");
return LValue::MakeVectorElt(LHS.getAddress(), Idx,
E->getBase()->getType(), LHS.getAlignment());
// Extend or truncate the index type to 32 or 64-bits.
if (Idx->getType() != IntPtrTy)
Idx = Builder.CreateIntCast(Idx, IntPtrTy, IdxSigned, "idxprom");
// We know that the pointer points to a type of the correct size, unless the
// size is a VLA or Objective-C interface.
llvm::Value *Address = 0;
CharUnits ArrayAlignment;
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.
Address = EmitScalarExpr(E->getBase());
// The element count here is the total number of non-VLA elements.
llvm::Value *numElements = getVLASize(vla).first;
// 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);
Address = Builder.CreateGEP(Address, Idx, "arrayidx");
} else {
Idx = Builder.CreateNSWMul(Idx, numElements);
Address = Builder.CreateInBoundsGEP(Address, Idx, "arrayidx");
} else if (const ObjCObjectType *OIT = E->getType()->getAs<ObjCObjectType>()){
// Indexing over an interface, as in "NSString *P; P[4];"
llvm::Value *InterfaceSize =
Idx = Builder.CreateMul(Idx, InterfaceSize);
// The base must be a pointer, which is not an aggregate. Emit it.
llvm::Value *Base = EmitScalarExpr(E->getBase());
Address = EmitCastToVoidPtr(Base);
Address = Builder.CreateGEP(Address, Idx, "arrayidx");
Address = Builder.CreateBitCast(Address, Base->getType());
} 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 = EmitLValue(Array);
llvm::Value *ArrayPtr = ArrayLV.getAddress();
llvm::Value *Zero = llvm::ConstantInt::get(Int32Ty, 0);
llvm::Value *Args[] = { Zero, Idx };
// Propagate the alignment from the array itself to the result.
ArrayAlignment = ArrayLV.getAlignment();
if (getContext().getLangOpts().isSignedOverflowDefined())
Address = Builder.CreateGEP(ArrayPtr, Args, "arrayidx");
Address = Builder.CreateInBoundsGEP(ArrayPtr, Args, "arrayidx");
} else {
// The base must be a pointer, which is not an aggregate. Emit it.
llvm::Value *Base = EmitScalarExpr(E->getBase());
if (getContext().getLangOpts().isSignedOverflowDefined())
Address = Builder.CreateGEP(Base, Idx, "arrayidx");
Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
QualType T = E->getBase()->getType()->getPointeeType();
assert(!T.isNull() &&
"CodeGenFunction::EmitArraySubscriptExpr(): Illegal base type");
// Limit the alignment to that of the result type.
LValue LV;
if (!ArrayAlignment.isZero()) {
CharUnits Align = getContext().getTypeAlignInChars(T);
ArrayAlignment = std::min(Align, ArrayAlignment);
LV = MakeAddrLValue(Address, T, ArrayAlignment);
} else {
LV = MakeNaturalAlignAddrLValue(Address, T);
if (getContext().getLangOpts().ObjC1 &&
getContext().getLangOpts().getGC() != LangOptions::NonGC) {
setObjCGCLValueClass(getContext(), E, LV);
return LV;
llvm::Constant *GenerateConstantVector(CGBuilderTy &Builder,
SmallVector<unsigned, 4> &Elts) {
SmallVector<llvm::Constant*, 4> CElts;
for (unsigned i = 0, e = Elts.size(); i != e; ++i)
return llvm::ConstantVector::get(CElts);
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.
llvm::Value *Ptr = EmitScalarExpr(E->getBase());
const PointerType *PT = E->getBase()->getType()->getAs<PointerType>();
Base = MakeAddrLValue(Ptr, PT->getPointeeType());
} 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.
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).
llvm::Value *VecMem = CreateMemTemp(E->getBase()->getType());
Builder.CreateStore(Vec, VecMem);
Base = MakeAddrLValue(VecMem, E->getBase()->getType());
QualType type =
// Encode the element access list into a vector of unsigned indices.
SmallVector<unsigned, 4> Indices;
if (Base.isSimple()) {
llvm::Constant *CV = GenerateConstantVector(Builder, Indices);
return LValue::MakeExtVectorElt(Base.getAddress(), CV, type,
assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
llvm::Constant *BaseElts = Base.getExtVectorElts();
SmallVector<llvm::Constant *, 4> CElts;
for (unsigned i = 0, e = Indices.size(); i != e; ++i)
llvm::Constant *CV = llvm::ConstantVector::get(CElts);
return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV, type,
LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
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())
BaseLV = MakeNaturalAlignAddrLValue(EmitScalarExpr(BaseExpr),
BaseLV = EmitLValue(BaseExpr);
NamedDecl *ND = E->getMemberDecl();
if (FieldDecl *Field = dyn_cast<FieldDecl>(ND)) {
LValue LV = EmitLValueForField(BaseLV, Field);
setObjCGCLValueClass(getContext(), E, LV);
return LV;
if (VarDecl *VD = dyn_cast<VarDecl>(ND))
return EmitGlobalVarDeclLValue(*this, E, VD);
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
return EmitFunctionDeclLValue(*this, E, FD);
llvm_unreachable("Unhandled member declaration!");
LValue CodeGenFunction::EmitLValueForBitfield(llvm::Value *BaseValue,
const FieldDecl *Field,
unsigned CVRQualifiers) {
const CGRecordLayout &RL =
const CGBitFieldInfo &Info = RL.getBitFieldInfo(Field);
return LValue::MakeBitfield(BaseValue, Info,
/// EmitLValueForAnonRecordField - Given that the field is a member of
/// an anonymous struct or union buried inside a record, and given
/// that the base value is a pointer to the enclosing record, derive
/// an lvalue for the ultimate field.
LValue CodeGenFunction::EmitLValueForAnonRecordField(llvm::Value *BaseValue,
const IndirectFieldDecl *Field,
unsigned CVRQualifiers) {
IndirectFieldDecl::chain_iterator I = Field->chain_begin(),
IEnd = Field->chain_end();
while (true) {
QualType RecordTy =
LValue LV = EmitLValueForField(MakeAddrLValue(BaseValue, RecordTy),
if (++I == IEnd) return LV;
BaseValue = LV.getAddress();
CVRQualifiers |= LV.getVRQualifiers();
LValue CodeGenFunction::EmitLValueForField(LValue base,
const FieldDecl *field) {
if (field->isBitField())
return EmitLValueForBitfield(base.getAddress(), field,
const RecordDecl *rec = field->getParent();
QualType type = field->getType();
CharUnits alignment = getContext().getDeclAlign(field);
// FIXME: It should be impossible to have an LValue without alignment for a
// complete type.
if (!base.getAlignment().isZero())
alignment = std::min(alignment, base.getAlignment());
bool mayAlias = rec->hasAttr<MayAliasAttr>();
llvm::Value *addr = base.getAddress();
unsigned cvr = base.getVRQualifiers();
if (rec->isUnion()) {
// For unions, there is no pointer adjustment.
assert(!type->isReferenceType() && "union has reference member");
} else {
// For structs, we GEP to the field that the record layout suggests.
unsigned idx = CGM.getTypes().getCGRecordLayout(rec).getLLVMFieldNo(field);
addr = Builder.CreateStructGEP(addr, idx, field->getName());
// If this is a reference field, load the reference right now.
if (const ReferenceType *refType = type->getAs<ReferenceType>()) {
llvm::LoadInst *load = Builder.CreateLoad(addr, "ref");
if (cvr & Qualifiers::Volatile) load->setVolatile(true);
if (CGM.shouldUseTBAA()) {
llvm::MDNode *tbaa;
if (mayAlias)
tbaa = CGM.getTBAAInfo(getContext().CharTy);
tbaa = CGM.getTBAAInfo(type);
CGM.DecorateInstruction(load, tbaa);
addr = load;
mayAlias = false;
type = refType->getPointeeType();
if (type->isIncompleteType())
alignment = CharUnits();
alignment = getContext().getTypeAlignInChars(type);
cvr = 0; // qualifiers don't recursively apply to referencee
// 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 = EmitBitCastOfLValueToProperType(*this, addr,
if (field->hasAttr<AnnotateAttr>())
addr = EmitFieldAnnotations(field, addr);
LValue LV = MakeAddrLValue(addr, type, alignment);
// __weak attribute on a field is ignored.
if (LV.getQuals().getObjCGCAttr() == Qualifiers::Weak)
// Fields of may_alias structs act like 'char' for TBAA purposes.
// FIXME: this should get propagated down through anonymous structs
// and unions.
if (mayAlias && LV.getTBAAInfo())
return LV;
CodeGenFunction::EmitLValueForFieldInitialization(LValue Base,
const FieldDecl *Field) {
QualType FieldType = Field->getType();
if (!FieldType->isReferenceType())
return EmitLValueForField(Base, Field);
const CGRecordLayout &RL =
unsigned idx = RL.getLLVMFieldNo(Field);
llvm::Value *V = Builder.CreateStructGEP(Base.getAddress(), idx);
assert(!FieldType.getObjCGCAttr() && "fields cannot have GC attrs");
// 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.
llvm::Type *llvmType = ConvertTypeForMem(FieldType);
V = EmitBitCastOfLValueToProperType(*this, V, llvmType, Field->getName());
CharUnits Alignment = getContext().getDeclAlign(Field);
// FIXME: It should be impossible to have an LValue without alignment for a
// complete type.
if (!Base.getAlignment().isZero())
Alignment = std::min(Alignment, Base.getAlignment());
return MakeAddrLValue(V, FieldType, Alignment);
LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr *E){
if (E->isFileScope()) {
llvm::Value *GlobalPtr = CGM.GetAddrOfConstantCompoundLiteral(E);
return MakeAddrLValue(GlobalPtr, E->getType());
if (E->getType()->isVariablyModifiedType())
// make sure to emit the VLA size.
llvm::Value *DeclPtr = CreateMemTemp(E->getType(), ".compoundliteral");
const Expr *InitExpr = E->getInitializer();
LValue Result = MakeAddrLValue(DeclPtr, E->getType());
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->getNumInits() == 1 && "reference init with multiple values");
return EmitLValue(E->getInit(0));
LValue CodeGenFunction::
EmitConditionalOperatorLValue(const AbstractConditionalOperator *expr) {
if (!expr->isGLValue()) {
// ?: here should be an aggregate.
assert((hasAggregateLLVMType(expr->getType()) &&
!expr->getType()->isAnyComplexType()) &&
"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))
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);
// Any temporaries created here are conditional.
LValue lhs = EmitLValue(expr->getTrueExpr());
if (!lhs.isSimple())
return EmitUnsupportedLValue(expr, "conditional operator");
lhsBlock = Builder.GetInsertBlock();
// Any temporaries created here are conditional.
LValue rhs = EmitLValue(expr->getFalseExpr());
if (!rhs.isSimple())
return EmitUnsupportedLValue(expr, "conditional operator");
rhsBlock = Builder.GetInsertBlock();
llvm::PHINode *phi = Builder.CreatePHI(lhs.getAddress()->getType(), 2,
phi->addIncoming(lhs.getAddress(), lhsBlock);
phi->addIncoming(rhs.getAddress(), rhsBlock);
return MakeAddrLValue(phi, expr->getType());
/// 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:
return EmitUnsupportedLValue(E, "unexpected cast lvalue");
case CK_Dependent:
llvm_unreachable("dependent cast kind in IR gen!");
// These two casts are currently treated as no-ops, although they could
// potentially be real operations depending on the target's ABI.
case CK_NonAtomicToAtomic:
case CK_AtomicToNonAtomic:
case CK_NoOp:
case CK_LValueToRValue:
if (!E->getSubExpr()->Classify(getContext()).isPRValue()
|| E->getType()->isRecordType())
return EmitLValue(E->getSubExpr());
// Fall through to synthesize a temporary.
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_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: {
// These casts only produce lvalues when we're binding a reference to a
// temporary realized from a (converted) pure rvalue. Emit the expression
// as a value, copy it into a temporary, and return an lvalue referring to
// that temporary.
llvm::Value *V = CreateMemTemp(E->getType(), "ref.temp");
EmitAnyExprToMem(E, V, E->getType().getQualifiers(), false);
return MakeAddrLValue(V, E->getType());
case CK_Dynamic: {
LValue LV = EmitLValue(E->getSubExpr());
llvm::Value *V = LV.getAddress();
const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(E);
return MakeAddrLValue(EmitDynamicCast(V, DCE), E->getType());
case CK_ConstructorConversion:
case CK_UserDefinedConversion:
case CK_CPointerToObjCPointerCast:
case CK_BlockPointerToObjCPointerCast:
return EmitLValue(E->getSubExpr());
case CK_UncheckedDerivedToBase:
case CK_DerivedToBase: {
const RecordType *DerivedClassTy =
CXXRecordDecl *DerivedClassDecl =
LValue LV = EmitLValue(E->getSubExpr());
llvm::Value *This = LV.getAddress();
// Perform the derived-to-base conversion
llvm::Value *Base =
GetAddressOfBaseClass(This, DerivedClassDecl,
E->path_begin(), E->path_end(),
return MakeAddrLValue(Base, E->getType());
case CK_ToUnion:
return EmitAggExprToLValue(E);
case CK_BaseToDerived: {
const RecordType *DerivedClassTy = E->getType()->getAs<RecordType>();
CXXRecordDecl *DerivedClassDecl =
LValue LV = EmitLValue(E->getSubExpr());
// Perform the base-to-derived conversion
llvm::Value *Derived =
GetAddressOfDerivedClass(LV.getAddress(), DerivedClassDecl,
E->path_begin(), E->path_end(),
return MakeAddrLValue(Derived, E->getType());
case CK_LValueBitCast: {
// This must be a reinterpret_cast (or c-style equivalent).
const ExplicitCastExpr *CE = cast<ExplicitCastExpr>(E);
LValue LV = EmitLValue(E->getSubExpr());
llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
return MakeAddrLValue(V, E->getType());
case CK_ObjCObjectLValueCast: {
LValue LV = EmitLValue(E->getSubExpr());
QualType ToType = getContext().getLValueReferenceType(E->getType());
llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
return MakeAddrLValue(V, E->getType());
llvm_unreachable("Unhandled lvalue cast kind?");
LValue CodeGenFunction::EmitNullInitializationLValue(
const CXXScalarValueInitExpr *E) {
QualType Ty = E->getType();
LValue LV = MakeAddrLValue(CreateMemTemp(Ty), Ty);
EmitNullInitialization(LV.getAddress(), Ty);
return LV;
LValue CodeGenFunction::EmitOpaqueValueLValue(const OpaqueValueExpr *e) {
return getOpaqueLValueMapping(e);
LValue CodeGenFunction::EmitMaterializeTemporaryExpr(
const MaterializeTemporaryExpr *E) {
RValue RV = EmitReferenceBindingToExpr(E, /*InitializedDecl=*/0);
return MakeAddrLValue(RV.getScalarVal(), E->getType());
RValue CodeGenFunction::EmitRValueForField(LValue LV,
const FieldDecl *FD) {
QualType FT = FD->getType();
LValue FieldLV = EmitLValueForField(LV, FD);
if (FT->isAnyComplexType())
return RValue::getComplex(
else if (CodeGenFunction::hasAggregateLLVMType(FT))
return FieldLV.asAggregateRValue();
return EmitLoadOfLValue(FieldLV);
// Expression Emission