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llvm-project/clang/lib/CodeGen/CGExpr.cpp

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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 https://llvm.org/LICENSE.txt 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 =
cast<llvm::PointerType>(value->getType())->getAddressSpace();
llvm::PointerType *destType = Int8PtrTy;
if (addressSpace)
destType = llvm::Type::getInt8PtrTy(getLLVMContext(), addressSpace);
if (value->getType() == destType) return value;
return Builder.CreateBitCast(value, destType);
}
/// CreateTempAlloca - This creates a alloca and inserts it into the entry
/// block.
Address CodeGenFunction::CreateTempAllocaWithoutCast(llvm::Type *Ty,
CharUnits Align,
const Twine &Name,
llvm::Value *ArraySize) {
auto Alloca = CreateTempAlloca(Ty, Name, ArraySize);
Alloca->setAlignment(Align.getQuantity());
return Address(Alloca, Align);
}
/// CreateTempAlloca - This creates a alloca and inserts it into the entry
/// block. The alloca is casted to default address space if necessary.
Address CodeGenFunction::CreateTempAlloca(llvm::Type *Ty, CharUnits Align,
const Twine &Name,
llvm::Value *ArraySize,
Address *AllocaAddr) {
auto Alloca = CreateTempAllocaWithoutCast(Ty, Align, Name, ArraySize);
if (AllocaAddr)
*AllocaAddr = Alloca;
llvm::Value *V = Alloca.getPointer();
// Alloca always returns a pointer in alloca address space, which may
// be different from the type defined by the language. For example,
// in C++ the auto variables are in the default address space. Therefore
// cast alloca to the default address space when necessary.
if (getASTAllocaAddressSpace() != LangAS::Default) {
auto DestAddrSpace = getContext().getTargetAddressSpace(LangAS::Default);
llvm::IRBuilderBase::InsertPointGuard IPG(Builder);
// When ArraySize is nullptr, alloca is inserted at AllocaInsertPt,
// otherwise alloca is inserted at the current insertion point of the
// builder.
if (!ArraySize)
Builder.SetInsertPoint(AllocaInsertPt);
V = getTargetHooks().performAddrSpaceCast(
*this, V, getASTAllocaAddressSpace(), LangAS::Default,
Ty->getPointerTo(DestAddrSpace), /*non-null*/ true);
}
return Address(V, Align);
}
/// CreateTempAlloca - This creates an alloca and inserts it into the entry
/// block if \p ArraySize is nullptr, otherwise inserts it at the current
/// insertion point of the builder.
llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(llvm::Type *Ty,
const Twine &Name,
llvm::Value *ArraySize) {
if (ArraySize)
return Builder.CreateAlloca(Ty, ArraySize, Name);
return new llvm::AllocaInst(Ty, CGM.getDataLayout().getAllocaAddrSpace(),
ArraySize, Name, AllocaInsertPt);
}
/// CreateDefaultAlignTempAlloca - This creates an alloca with the
/// default alignment of the corresponding LLVM type, which is *not*
/// guaranteed to be related in any way to the expected alignment of
/// an AST type that might have been lowered to Ty.
Address CodeGenFunction::CreateDefaultAlignTempAlloca(llvm::Type *Ty,
const Twine &Name) {
CharUnits Align =
CharUnits::fromQuantity(CGM.getDataLayout().getABITypeAlignment(Ty));
return CreateTempAlloca(Ty, Align, Name);
}
void CodeGenFunction::InitTempAlloca(Address Var, llvm::Value *Init) {
assert(isa<llvm::AllocaInst>(Var.getPointer()));
auto *Store = new llvm::StoreInst(Init, Var.getPointer());
Store->setAlignment(Var.getAlignment().getQuantity());
llvm::BasicBlock *Block = AllocaInsertPt->getParent();
Block->getInstList().insertAfter(AllocaInsertPt->getIterator(), Store);
}
Address CodeGenFunction::CreateIRTemp(QualType Ty, const Twine &Name) {
CharUnits Align = getContext().getTypeAlignInChars(Ty);
return CreateTempAlloca(ConvertType(Ty), Align, Name);
}
Address CodeGenFunction::CreateMemTemp(QualType Ty, const Twine &Name,
Address *Alloca) {
// FIXME: Should we prefer the preferred type alignment here?
return CreateMemTemp(Ty, getContext().getTypeAlignInChars(Ty), Name, Alloca);
}
Address CodeGenFunction::CreateMemTemp(QualType Ty, CharUnits Align,
const Twine &Name, Address *Alloca) {
return CreateTempAlloca(ConvertTypeForMem(Ty), Align, Name,
/*ArraySize=*/nullptr, Alloca);
}
Address CodeGenFunction::CreateMemTempWithoutCast(QualType Ty, CharUnits Align,
const Twine &Name) {
return CreateTempAllocaWithoutCast(ConvertTypeForMem(Ty), Align, Name);
}
Address CodeGenFunction::CreateMemTempWithoutCast(QualType Ty,
const Twine &Name) {
return CreateMemTempWithoutCast(Ty, getContext().getTypeAlignInChars(Ty),
Name);
}
/// EvaluateExprAsBool - Perform the usual unary conversions on the specified
/// expression and compare the result against zero, returning an Int1Ty value.
llvm::Value *CodeGenFunction::EvaluateExprAsBool(const Expr *E) {
PGO.setCurrentStmt(E);
if (const MemberPointerType *MPT = E->getType()->getAs<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,
Loc);
}
/// EmitIgnoredExpr - Emit code to compute the specified expression,
/// ignoring the result.
void CodeGenFunction::EmitIgnoredExpr(const Expr *E) {
if (E->isRValue())
return (void) EmitAnyExpr(E, AggValueSlot::ignored(), true);
// Just emit it as an l-value and drop the result.
EmitLValue(E);
}
/// EmitAnyExpr - Emit code to compute the specified expression which
/// can have any type. The result is returned as an RValue struct.
/// If this is an aggregate expression, AggSlot indicates where the
/// result should be returned.
RValue CodeGenFunction::EmitAnyExpr(const Expr *E,
AggValueSlot aggSlot,
bool ignoreResult) {
switch (getEvaluationKind(E->getType())) {
case TEK_Scalar:
return RValue::get(EmitScalarExpr(E, ignoreResult));
case TEK_Complex:
return RValue::getComplex(EmitComplexExpr(E, ignoreResult, ignoreResult));
case TEK_Aggregate:
if (!ignoreResult && aggSlot.isIgnored())
aggSlot = CreateAggTemp(E->getType(), "agg-temp");
EmitAggExpr(E, aggSlot);
return aggSlot.asRValue();
}
llvm_unreachable("bad evaluation kind");
}
/// EmitAnyExprToTemp - Similar to EmitAnyExpr(), however, the result will
/// always be accessible even if no aggregate location is provided.
RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E) {
AggValueSlot AggSlot = AggValueSlot::ignored();
if (hasAggregateEvaluationKind(E->getType()))
AggSlot = CreateAggTemp(E->getType(), "agg.tmp");
return EmitAnyExpr(E, AggSlot);
}
/// EmitAnyExprToMem - Evaluate an expression into a given memory
/// location.
void CodeGenFunction::EmitAnyExprToMem(const Expr *E,
Address Location,
Qualifiers Quals,
bool IsInit) {
// FIXME: This function should take an LValue as an argument.
switch (getEvaluationKind(E->getType())) {
case TEK_Complex:
EmitComplexExprIntoLValue(E, MakeAddrLValue(Location, E->getType()),
/*isInit*/ false);
return;
case TEK_Aggregate: {
EmitAggExpr(E, AggValueSlot::forAddr(Location, Quals,
AggValueSlot::IsDestructed_t(IsInit),
AggValueSlot::DoesNotNeedGCBarriers,
AggValueSlot::IsAliased_t(!IsInit),
AggValueSlot::MayOverlap));
return;
}
case TEK_Scalar: {
RValue RV = RValue::get(EmitScalarExpr(E, /*Ignore*/ false));
LValue LV = MakeAddrLValue(Location, E->getType());
EmitStoreThroughLValue(RV, LV);
return;
}
}
llvm_unreachable("bad evaluation kind");
}
static void
pushTemporaryCleanup(CodeGenFunction &CGF, const MaterializeTemporaryExpr *M,
const Expr *E, Address ReferenceTemporary) {
// Objective-C++ ARC:
// If we are binding a reference to a temporary that has ownership, we
// need to perform retain/release operations on the temporary.
//
// FIXME: This should be looking at E, not M.
if (auto Lifetime = M->getType().getObjCLifetime()) {
switch (Lifetime) {
case Qualifiers::OCL_None:
case Qualifiers::OCL_ExplicitNone:
// Carry on to normal cleanup handling.
break;
case Qualifiers::OCL_Autoreleasing:
// Nothing to do; cleaned up by an autorelease pool.
return;
case Qualifiers::OCL_Strong:
case Qualifiers::OCL_Weak:
switch (StorageDuration Duration = M->getStorageDuration()) {
case SD_Static:
// Note: we intentionally do not register a cleanup to release
// the object on program termination.
return;
case SD_Thread:
// FIXME: We should probably register a cleanup in this case.
return;
case SD_Automatic:
case SD_FullExpression:
CodeGenFunction::Destroyer *Destroy;
CleanupKind CleanupKind;
if (Lifetime == Qualifiers::OCL_Strong) {
const ValueDecl *VD = M->getExtendingDecl();
bool Precise =
VD && isa<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);
else
CGF.pushLifetimeExtendedDestroy(CleanupKind, ReferenceTemporary,
M->getType(),
*Destroy, CleanupKind & EHCleanup);
return;
case SD_Dynamic:
llvm_unreachable("temporary cannot have dynamic storage duration");
}
llvm_unreachable("unknown storage duration");
}
}
CXXDestructorDecl *ReferenceTemporaryDtor = nullptr;
if (const RecordType *RT =
E->getType()->getBaseElementTypeUnsafe()->getAs<RecordType>()) {
// Get the destructor for the reference temporary.
auto *ClassDecl = cast<CXXRecordDecl>(RT->getDecl());
if (!ClassDecl->hasTrivialDestructor())
ReferenceTemporaryDtor = ClassDecl->getDestructor();
}
if (!ReferenceTemporaryDtor)
return;
// Call the destructor for the temporary.
switch (M->getStorageDuration()) {
case SD_Static:
case SD_Thread: {
llvm::FunctionCallee CleanupFn;
llvm::Constant *CleanupArg;
if (E->getType()->isArrayType()) {
CleanupFn = CodeGenFunction(CGF.CGM).generateDestroyHelper(
ReferenceTemporary, E->getType(),
CodeGenFunction::destroyCXXObject, CGF.getLangOpts().Exceptions,
dyn_cast_or_null<VarDecl>(M->getExtendingDecl()));
CleanupArg = llvm::Constant::getNullValue(CGF.Int8PtrTy);
} else {
CleanupFn = CGF.CGM.getAddrAndTypeOfCXXStructor(
GlobalDecl(ReferenceTemporaryDtor, Dtor_Complete));
CleanupArg = cast<llvm::Constant>(ReferenceTemporary.getPointer());
}
CGF.CGM.getCXXABI().registerGlobalDtor(
CGF, *cast<VarDecl>(M->getExtendingDecl()), CleanupFn, CleanupArg);
break;
}
case SD_FullExpression:
CGF.pushDestroy(NormalAndEHCleanup, ReferenceTemporary, E->getType(),
CodeGenFunction::destroyCXXObject,
CGF.getLangOpts().Exceptions);
break;
case SD_Automatic:
CGF.pushLifetimeExtendedDestroy(NormalAndEHCleanup,
ReferenceTemporary, E->getType(),
CodeGenFunction::destroyCXXObject,
CGF.getLangOpts().Exceptions);
break;
case SD_Dynamic:
llvm_unreachable("temporary cannot have dynamic storage duration");
}
}
static Address createReferenceTemporary(CodeGenFunction &CGF,
const MaterializeTemporaryExpr *M,
const Expr *Inner,
Address *Alloca = nullptr) {
auto &TCG = CGF.getTargetHooks();
switch (M->getStorageDuration()) {
case SD_FullExpression:
case SD_Automatic: {
// If we have a constant temporary array or record try to promote it into a
// constant global under the same rules a normal constant would've been
// promoted. This is easier on the optimizer and generally emits fewer
// instructions.
QualType Ty = Inner->getType();
if (CGF.CGM.getCodeGenOpts().MergeAllConstants &&
(Ty->isArrayType() || Ty->isRecordType()) &&
CGF.CGM.isTypeConstant(Ty, true))
if (auto Init = ConstantEmitter(CGF).tryEmitAbstract(Inner, Ty)) {
if (auto AddrSpace = CGF.getTarget().getConstantAddressSpace()) {
auto AS = AddrSpace.getValue();
auto *GV = new llvm::GlobalVariable(
CGF.CGM.getModule(), Init->getType(), /*isConstant=*/true,
llvm::GlobalValue::PrivateLinkage, Init, ".ref.tmp", nullptr,
llvm::GlobalValue::NotThreadLocal,
CGF.getContext().getTargetAddressSpace(AS));
CharUnits alignment = CGF.getContext().getTypeAlignInChars(Ty);
GV->setAlignment(alignment.getQuantity());
llvm::Constant *C = GV;
if (AS != LangAS::Default)
C = TCG.performAddrSpaceCast(
CGF.CGM, GV, AS, LangAS::Default,
GV->getValueType()->getPointerTo(
CGF.getContext().getTargetAddressSpace(LangAS::Default)));
// FIXME: Should we put the new global into a COMDAT?
return Address(C, alignment);
}
}
return CGF.CreateMemTemp(Ty, "ref.tmp", Alloca);
}
case SD_Thread:
case SD_Static:
return CGF.CGM.GetAddrOfGlobalTemporary(M, Inner);
case SD_Dynamic:
llvm_unreachable("temporary can't have dynamic storage duration");
}
llvm_unreachable("unknown storage duration");
}
LValue CodeGenFunction::
EmitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *M) {
const Expr *E = M->GetTemporaryExpr();
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,
ConvertTypeForMem(E->getType())
->getPointerTo(Object.getAddressSpace())),
Object.getAlignment());
// createReferenceTemporary will promote the temporary to a global with a
// constant initializer if it can. It can only do this to a value of
// ARC-manageable type if the value is global and therefore "immune" to
// ref-counting operations. Therefore we have no need to emit either a
// dynamic initialization or a cleanup and we can just return the address
// of the temporary.
if (Var->hasInitializer())
return MakeAddrLValue(Object, M->getType(), AlignmentSource::Decl);
Var->setInitializer(CGM.EmitNullConstant(E->getType()));
}
LValue RefTempDst = MakeAddrLValue(Object, M->getType(),
AlignmentSource::Decl);
switch (getEvaluationKind(E->getType())) {
default: llvm_unreachable("expected scalar or aggregate expression");
case TEK_Scalar:
EmitScalarInit(E, M->getExtendingDecl(), RefTempDst, false);
break;
case TEK_Aggregate: {
EmitAggExpr(E, AggValueSlot::forAddr(Object,
E->getType().getQualifiers(),
AggValueSlot::IsDestructed,
AggValueSlot::DoesNotNeedGCBarriers,
AggValueSlot::IsNotAliased,
AggValueSlot::DoesNotOverlap));
break;
}
}
pushTemporaryCleanup(*this, M, E, Object);
return RefTempDst;
}
SmallVector<const Expr *, 2> CommaLHSs;
SmallVector<SubobjectAdjustment, 2> Adjustments;
E = E->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
for (const auto &Ignored : CommaLHSs)
EmitIgnoredExpr(Ignored);
if (const auto *opaque = dyn_cast<OpaqueValueExpr>(E)) {
if (opaque->getType()->isRecordType()) {
assert(Adjustments.empty());
return EmitOpaqueValueLValue(opaque);
}
}
// Create and initialize the reference temporary.
Address Alloca = Address::invalid();
Address Object = createReferenceTemporary(*this, M, E, &Alloca);
if (auto *Var = dyn_cast<llvm::GlobalVariable>(
Object.getPointer()->stripPointerCasts())) {
Object = Address(llvm::ConstantExpr::getBitCast(
cast<llvm::Constant>(Object.getPointer()),
ConvertTypeForMem(E->getType())->getPointerTo()),
Object.getAlignment());
// If the temporary is a global and has a constant initializer or is a
// constant temporary that we promoted to a global, we may have already
// initialized it.
if (!Var->hasInitializer()) {
Var->setInitializer(CGM.EmitNullConstant(E->getType()));
EmitAnyExprToMem(E, Object, Qualifiers(), /*IsInit*/true);
}
} else {
switch (M->getStorageDuration()) {
case SD_Automatic:
if (auto *Size = EmitLifetimeStart(
CGM.getDataLayout().getTypeAllocSize(Alloca.getElementType()),
Alloca.getPointer())) {
pushCleanupAfterFullExpr<CallLifetimeEnd>(NormalEHLifetimeMarker,
Alloca, Size);
}
break;
case SD_FullExpression: {
if (!ShouldEmitLifetimeMarkers)
break;
// 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 in ASan's use-after-scope
// mode so that it gets the more precise lifetime marks. If the type has
// a non-trivial destructor, we'll have a cleanup block for it anyway,
// so this typically doesn't help; skip it in that case.
ConditionalEvaluation *OldConditional = nullptr;
CGBuilderTy::InsertPoint OldIP;
if (isInConditionalBranch() && !E->getType().isDestructedType() &&
!CGM.getCodeGenOpts().SanitizeAddressUseAfterScope) {
OldConditional = OutermostConditional;
OutermostConditional = nullptr;
OldIP = Builder.saveIP();
llvm::BasicBlock *Block = OldConditional->getStartingBlock();
Builder.restoreIP(CGBuilderTy::InsertPoint(
Block, llvm::BasicBlock::iterator(Block->back())));
}
if (auto *Size = EmitLifetimeStart(
CGM.getDataLayout().getTypeAllocSize(Alloca.getElementType()),
Alloca.getPointer())) {
pushFullExprCleanup<CallLifetimeEnd>(NormalEHLifetimeMarker, Alloca,
Size);
}
if (OldConditional) {
OutermostConditional = OldConditional;
Builder.restoreIP(OldIP);
}
break;
}
default:
break;
}
EmitAnyExprToMem(E, Object, Qualifiers(), /*IsInit*/true);
}
pushTemporaryCleanup(*this, M, E, Object);
// Perform derived-to-base casts and/or field accesses, to get from the
// temporary object we created (and, potentially, for which we extended
// the lifetime) to the subobject we're binding the reference to.
for (unsigned I = Adjustments.size(); I != 0; --I) {
SubobjectAdjustment &Adjustment = Adjustments[I-1];
switch (Adjustment.Kind) {
case SubobjectAdjustment::DerivedToBaseAdjustment:
Object =
GetAddressOfBaseClass(Object, Adjustment.DerivedToBase.DerivedClass,
Adjustment.DerivedToBase.BasePath->path_begin(),
Adjustment.DerivedToBase.BasePath->path_end(),
/*NullCheckValue=*/ false, E->getExprLoc());
break;
case SubobjectAdjustment::FieldAdjustment: {
LValue LV = MakeAddrLValue(Object, E->getType(), AlignmentSource::Decl);
LV = EmitLValueForField(LV, Adjustment.Field);
assert(LV.isSimple() &&
"materialized temporary field is not a simple lvalue");
Object = LV.getAddress();
break;
}
case SubobjectAdjustment::MemberPointerAdjustment: {
llvm::Value *Ptr = EmitScalarExpr(Adjustment.Ptr.RHS);
Object = EmitCXXMemberDataPointerAddress(E, Object, Ptr,
Adjustment.Ptr.MPT);
break;
}
}
}
return MakeAddrLValue(Object, M->getType(), AlignmentSource::Decl);
}
RValue
CodeGenFunction::EmitReferenceBindingToExpr(const Expr *E) {
// Emit the expression as an lvalue.
LValue LV = EmitLValue(E);
assert(LV.isSimple());
llvm::Value *Value = LV.getPointer();
if (sanitizePerformTypeCheck() && !E->getType()->isFunctionType()) {
// C++11 [dcl.ref]p5 (as amended by core issue 453):
// If a glvalue to which a reference is directly bound designates neither
// an existing object or function of an appropriate type nor a region of
// storage of suitable size and alignment to contain an object of the
// reference's type, the behavior is undefined.
QualType Ty = E->getType();
EmitTypeCheck(TCK_ReferenceBinding, E->getExprLoc(), Value, Ty);
}
return RValue::get(Value);
}
/// getAccessedFieldNo - Given an encoded value and a result number, return the
/// input field number being accessed.
unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
const llvm::Constant *Elts) {
return cast<llvm::ConstantInt>(Elts->getAggregateElement(Idx))
->getZExtValue();
}
/// Emit the hash_16_bytes function from include/llvm/ADT/Hashing.h.
static llvm::Value *emitHash16Bytes(CGBuilderTy &Builder, llvm::Value *Low,
llvm::Value *High) {
llvm::Value *KMul = Builder.getInt64(0x9ddfea08eb382d69ULL);
llvm::Value *K47 = Builder.getInt64(47);
llvm::Value *A0 = Builder.CreateMul(Builder.CreateXor(Low, High), KMul);
llvm::Value *A1 = Builder.CreateXor(Builder.CreateLShr(A0, K47), A0);
llvm::Value *B0 = Builder.CreateMul(Builder.CreateXor(High, A1), KMul);
llvm::Value *B1 = Builder.CreateXor(Builder.CreateLShr(B0, K47), B0);
return Builder.CreateMul(B1, KMul);
}
bool CodeGenFunction::isNullPointerAllowed(TypeCheckKind TCK) {
return TCK == TCK_DowncastPointer || TCK == TCK_Upcast ||
TCK == TCK_UpcastToVirtualBase || TCK == TCK_DynamicOperation;
}
bool CodeGenFunction::isVptrCheckRequired(TypeCheckKind TCK, QualType Ty) {
CXXRecordDecl *RD = Ty->getAsCXXRecordDecl();
return (RD && RD->hasDefinition() && RD->isDynamicClass()) &&
(TCK == TCK_MemberAccess || TCK == TCK_MemberCall ||
TCK == TCK_DowncastPointer || TCK == TCK_DowncastReference ||
TCK == TCK_UpcastToVirtualBase || TCK == TCK_DynamicOperation);
}
bool CodeGenFunction::sanitizePerformTypeCheck() const {
return SanOpts.has(SanitizerKind::Null) |
SanOpts.has(SanitizerKind::Alignment) |
SanOpts.has(SanitizerKind::ObjectSize) |
SanOpts.has(SanitizerKind::Vptr);
}
void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc,
llvm::Value *Ptr, QualType Ty,
CharUnits Alignment,
SanitizerSet SkippedChecks,
llvm::Value *ArraySize) {
if (!sanitizePerformTypeCheck())
return;
// Don't check pointers outside the default address space. The null check
// isn't correct, the object-size check isn't supported by LLVM, and we can't
// communicate the addresses to the runtime handler for the vptr check.
if (Ptr->getType()->getPointerAddressSpace())
return;
// Don't check pointers to volatile data. The behavior here is implementation-
// defined.
if (Ty.isVolatileQualified())
return;
SanitizerScope SanScope(this);
SmallVector<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->stripPointerCastsNoFollowAliases());
llvm::Value *True = llvm::ConstantInt::getTrue(getLLVMContext());
llvm::Value *IsNonNull = nullptr;
bool IsGuaranteedNonNull =
SkippedChecks.has(SanitizerKind::Null) || PtrToAlloca;
bool AllowNullPointers = isNullPointerAllowed(TCK);
if ((SanOpts.has(SanitizerKind::Null) || AllowNullPointers) &&
!IsGuaranteedNonNull) {
// The glvalue must not be an empty glvalue.
IsNonNull = Builder.CreateIsNotNull(Ptr);
// The IR builder can constant-fold the null check if the pointer points to
// a constant.
IsGuaranteedNonNull = IsNonNull == True;
// Skip the null check if the pointer is known to be non-null.
if (!IsGuaranteedNonNull) {
if (AllowNullPointers) {
// When performing pointer casts, it's OK if the value is null.
// Skip the remaining checks in that case.
Done = createBasicBlock("null");
llvm::BasicBlock *Rest = createBasicBlock("not.null");
Builder.CreateCondBr(IsNonNull, Rest, Done);
EmitBlock(Rest);
} else {
Checks.push_back(std::make_pair(IsNonNull, SanitizerKind::Null));
}
}
}
if (SanOpts.has(SanitizerKind::ObjectSize) &&
!SkippedChecks.has(SanitizerKind::ObjectSize) &&
!Ty->isIncompleteType()) {
uint64_t 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 [basic.life]p5,6:
// [For storage which does not refer to an object within its lifetime]
// The program has undefined behavior if:
// -- the [pointer or glvalue] is used to access a non-static data member
// or call a non-static member function
if (SanOpts.has(SanitizerKind::Vptr) &&
!SkippedChecks.has(SanitizerKind::Vptr) && isVptrCheckRequired(TCK, Ty)) {
// Ensure that the pointer is non-null before loading it. If there is no
// compile-time guarantee, reuse the run-time null check or emit a new one.
if (!IsGuaranteedNonNull) {
if (!IsNonNull)
IsNonNull = Builder.CreateIsNotNull(Ptr);
if (!Done)
Done = createBasicBlock("vptr.null");
llvm::BasicBlock *VptrNotNull = createBasicBlock("vptr.not.null");
Builder.CreateCondBr(IsNonNull, VptrNotNull, Done);
EmitBlock(VptrNotNull);
}
// Compute a hash of the mangled name of the type.
//
// FIXME: This is not guaranteed to be deterministic! Move to a
// fingerprinting mechanism once LLVM provides one. For the time
// being the implementation happens to be deterministic.
SmallString<64> MangledName;
llvm::raw_svector_ostream Out(MangledName);
CGM.getCXXABI().getMangleContext().mangleCXXRTTI(Ty.getUnqualifiedType(),
Out);
// Blacklist based on the mangled type.
if (!CGM.getContext().getSanitizerBlacklist().isBlacklistedType(
SanitizerKind::Vptr, Out.str())) {
llvm::hash_code TypeHash = hash_value(Out.str());
// Load the vptr, and compute hash_16_bytes(TypeHash, vptr).
llvm::Value *Low = llvm::ConstantInt::get(Int64Ty, TypeHash);
llvm::Type *VPtrTy = llvm::PointerType::get(IntPtrTy, 0);
Address VPtrAddr(Builder.CreateBitCast(Ptr, VPtrTy), getPointerAlign());
llvm::Value *VPtrVal = Builder.CreateLoad(VPtrAddr);
llvm::Value *High = Builder.CreateZExt(VPtrVal, Int64Ty);
llvm::Value *Hash = emitHash16Bytes(Builder, Low, High);
Hash = Builder.CreateTrunc(Hash, IntPtrTy);
// Look the hash up in our cache.
const int CacheSize = 128;
llvm::Type *HashTable = llvm::ArrayType::get(IntPtrTy, CacheSize);
llvm::Value *Cache = CGM.CreateRuntimeVariable(HashTable,
"__ubsan_vptr_type_cache");
llvm::Value *Slot = Builder.CreateAnd(Hash,
llvm::ConstantInt::get(IntPtrTy,
CacheSize-1));
llvm::Value *Indices[] = { Builder.getInt32(0), Slot };
llvm::Value *CacheVal =
Builder.CreateAlignedLoad(Builder.CreateInBoundsGEP(Cache, Indices),
getPointerAlign());
// If the hash isn't in the cache, call a runtime handler to perform the
// hard work of checking whether the vptr is for an object of the right
// type. This will either fill in the cache and return, or produce a
// diagnostic.
llvm::Value *EqualHash = Builder.CreateICmpEQ(CacheVal, Hash);
llvm::Constant *StaticData[] = {
EmitCheckSourceLocation(Loc),
EmitCheckTypeDescriptor(Ty),
CGM.GetAddrOfRTTIDescriptor(Ty.getUnqualifiedType()),
llvm::ConstantInt::get(Int8Ty, TCK)
};
llvm::Value *DynamicData[] = { Ptr, Hash };
EmitCheck(std::make_pair(EqualHash, SanitizerKind::Vptr),
SanitizerHandler::DynamicTypeCacheMiss, StaticData,
DynamicData);
}
}
if (Done) {
Builder.CreateBr(Done);
EmitBlock(Done);
}
}
/// Determine whether this expression refers to a flexible array member in a
/// struct. We disable array bounds checks for such members.
static bool isFlexibleArrayMemberExpr(const Expr *E) {
// For compatibility with existing code, we treat arrays of length 0 or
// 1 as flexible array members.
const ArrayType *AT = E->getType()->castAsArrayTypeUnsafe();
if (const auto *CAT = dyn_cast<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)
return;
bool IndexSigned = IndexType->isSignedIntegerOrEnumerationType();
llvm::Value *IndexVal = Builder.CreateIntCast(Index, SizeTy, IndexSigned);
llvm::Value *BoundVal = Builder.CreateIntCast(Bound, SizeTy, false);
llvm::Constant *StaticData[] = {
EmitCheckSourceLocation(E->getExprLoc()),
EmitCheckTypeDescriptor(IndexedType),
EmitCheckTypeDescriptor(IndexType)
};
llvm::Value *Check = Accessed ? Builder.CreateICmpULT(IndexVal, BoundVal)
: Builder.CreateICmpULE(IndexVal, BoundVal);
EmitCheck(std::make_pair(Check, SanitizerKind::ArrayBounds),
SanitizerHandler::OutOfBounds, StaticData, Index);
}
CodeGenFunction::ComplexPairTy CodeGenFunction::
EmitComplexPrePostIncDec(const UnaryOperator *E, LValue LV,
bool isInc, bool isPre) {
ComplexPairTy InVal = EmitLoadOfComplex(LV, E->getExprLoc());
llvm::Value *NextVal;
if (isa<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)
FVal.changeSign();
NextVal = llvm::ConstantFP::get(getLLVMContext(), FVal);
// Add the inc/dec to the real part.
NextVal = Builder.CreateFAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
}
ComplexPairTy IncVal(NextVal, InVal.second);
// Store the updated result through the lvalue.
EmitStoreOfComplex(IncVal, LV, /*init*/ false);
// If this is a postinc, return the value read from memory, otherwise use the
// updated value.
return isPre ? IncVal : InVal;
}
void CodeGenModule::EmitExplicitCastExprType(const ExplicitCastExpr *E,
CodeGenFunction *CGF) {
// Bind VLAs in the cast type.
if (CGF && E->getType()->isVariablyModifiedType())
CGF->EmitVariablyModifiedType(E->getType());
if (CGDebugInfo *DI = getModuleDebugInfo())
DI->EmitExplicitCastType(E->getType());
}
//===----------------------------------------------------------------------===//
// LValue Expression Emission
//===----------------------------------------------------------------------===//
/// EmitPointerWithAlignment - Given an expression of pointer type, try to
/// derive a more accurate bound on the alignment of the pointer.
Address CodeGenFunction::EmitPointerWithAlignment(const Expr *E,
LValueBaseInfo *BaseInfo,
TBAAAccessInfo *TBAAInfo) {
// We allow this with ObjC object pointers because of fragile ABIs.
assert(E->getType()->isPointerType() ||
E->getType()->isObjCObjectPointerType());
E = E->IgnoreParens();
// Casts:
if (const CastExpr *CE = dyn_cast<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())
break;
LValueBaseInfo InnerBaseInfo;
TBAAAccessInfo InnerTBAAInfo;
Address Addr = EmitPointerWithAlignment(CE->getSubExpr(),
&InnerBaseInfo,
&InnerTBAAInfo);
if (BaseInfo) *BaseInfo = InnerBaseInfo;
if (TBAAInfo) *TBAAInfo = InnerTBAAInfo;
if (isa<ExplicitCastExpr>(CE)) {
LValueBaseInfo TargetTypeBaseInfo;
TBAAAccessInfo TargetTypeTBAAInfo;
CharUnits Align = getNaturalPointeeTypeAlignment(E->getType(),
&TargetTypeBaseInfo,
&TargetTypeTBAAInfo);
if (TBAAInfo)
*TBAAInfo = CGM.mergeTBAAInfoForCast(*TBAAInfo,
TargetTypeTBAAInfo);
// If the source l-value is opaque, honor the alignment of the
// casted-to type.
if (InnerBaseInfo.getAlignmentSource() != AlignmentSource::Decl) {
if (BaseInfo)
BaseInfo->mergeForCast(TargetTypeBaseInfo);
Addr = Address(Addr.getPointer(), Align);
}
}
if (SanOpts.has(SanitizerKind::CFIUnrelatedCast) &&
CE->getCastKind() == CK_BitCast) {
if (auto PT = E->getType()->getAs<PointerType>())
EmitVTablePtrCheckForCast(PT->getPointeeType(), Addr.getPointer(),
/*MayBeNull=*/true,
CodeGenFunction::CFITCK_UnrelatedCast,
CE->getBeginLoc());
}
return CE->getCastKind() != CK_AddressSpaceConversion
? Builder.CreateBitCast(Addr, ConvertType(E->getType()))
: Builder.CreateAddrSpaceCast(Addr,
ConvertType(E->getType()));
}
break;
// Array-to-pointer decay.
case CK_ArrayToPointerDecay:
return EmitArrayToPointerDecay(CE->getSubExpr(), BaseInfo, TBAAInfo);
// Derived-to-base conversions.
case CK_UncheckedDerivedToBase:
case CK_DerivedToBase: {
// TODO: Support accesses to members of base classes in TBAA. For now, we
// conservatively pretend that the complete object is of the base class
// type.
if (TBAAInfo)
*TBAAInfo = CGM.getTBAAAccessInfo(E->getType());
Address Addr = EmitPointerWithAlignment(CE->getSubExpr(), BaseInfo);
auto Derived = CE->getSubExpr()->getType()->getPointeeCXXRecordDecl();
return GetAddressOfBaseClass(Addr, Derived,
CE->path_begin(), CE->path_end(),
ShouldNullCheckClassCastValue(CE),
CE->getExprLoc());
}
// TODO: Is there any reason to treat base-to-derived conversions
// specially?
default:
break;
}
}
// Unary &.
if (const UnaryOperator *UO = dyn_cast<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,
TBAAInfo);
return Address(EmitScalarExpr(E), Align);
}
RValue CodeGenFunction::GetUndefRValue(QualType Ty) {
if (Ty->isVoidType())
return RValue::get(nullptr);
switch (getEvaluationKind(Ty)) {
case TEK_Complex: {
llvm::Type *EltTy =
ConvertType(Ty->castAs<ComplexType>()->getElementType());
llvm::Value *U = llvm::UndefValue::get(EltTy);
return RValue::getComplex(std::make_pair(U, U));
}
// If this is a use of an undefined aggregate type, the aggregate must have an
// identifiable address. Just because the contents of the value are undefined
// doesn't mean that the address can't be taken and compared.
case TEK_Aggregate: {
Address DestPtr = CreateMemTemp(Ty, "undef.agg.tmp");
return RValue::getAggregate(DestPtr);
}
case TEK_Scalar:
return RValue::get(llvm::UndefValue::get(ConvertType(Ty)));
}
llvm_unreachable("bad evaluation kind");
}
RValue CodeGenFunction::EmitUnsupportedRValue(const Expr *E,
const char *Name) {
ErrorUnsupported(E, Name);
return GetUndefRValue(E->getType());
}
LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
const char *Name) {
ErrorUnsupported(E, Name);
llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
return MakeAddrLValue(Address(llvm::UndefValue::get(Ty), CharUnits::One()),
E->getType());
}
bool CodeGenFunction::IsWrappedCXXThis(const Expr *Obj) {
const Expr *Base = Obj;
while (!isa<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();
else
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);
else
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);
enterFullExpression(cleanups);
RunCleanupsScope Scope(*this);
LValue LV = EmitLValue(cleanups->getSubExpr());
if (LV.isSimple()) {
// Defend against branches out of gnu statement expressions surrounded by
// cleanups.
llvm::Value *V = LV.getPointer();
Scope.ForceCleanup({&V});
return LValue::MakeAddr(Address(V, LV.getAlignment()), LV.getType(),
getContext(), LV.getBaseInfo(), LV.getTBAAInfo());
}
// FIXME: Is it possible to create an ExprWithCleanups that produces a
// bitfield lvalue or some other non-simple lvalue?
return LV;
}
case Expr::CXXDefaultArgExprClass: {
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) {
assert(type.isCanonical());
assert(!type->isReferenceType());
// Must be const-qualified but non-volatile.
Qualifiers qs = type.getLocalQualifiers();
if (!qs.hasConst() || qs.hasVolatile()) return false;
// Otherwise, all object types satisfy this except C++ classes with
// mutable subobjects or non-trivial copy/destroy behavior.
if (const auto *RT = dyn_cast<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 {
CEK_None,
CEK_AsReferenceOnly,
CEK_AsValueOrReference,
CEK_AsValueOnly
};
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::ConstantEmission
CodeGenFunction::tryEmitAsConstant(DeclRefExpr *refExpr) {
ValueDecl *value = refExpr->getDecl();
// The value needs to be an enum constant or a constant variable.
ConstantEmissionKind CEK;
if (isa<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 {
assert(isa<EnumConstantDecl>(value));
EmitDeclRefExprDbgValue(refExpr, result.Val);
}
// If we emitted a reference constant, we need to dereference that.
if (resultIsReference)
return ConstantEmission::forReference(C);
return ConstantEmission::forValue(C);
}
static DeclRefExpr *tryToConvertMemberExprToDeclRefExpr(CodeGenFunction &CGF,
const MemberExpr *ME) {
if (auto *VD = dyn_cast<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::ConstantEmission
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),
E->getExprLoc())
.getScalarVal();
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,
hasBooleanRepresentation(Ty)))
return nullptr;
llvm::MDBuilder MDHelper(getLLVMContext());
return MDHelper.createRange(Min, End);
}
bool CodeGenFunction::EmitScalarRangeCheck(llvm::Value *Value, QualType Ty,
SourceLocation Loc) {
bool HasBoolCheck = SanOpts.has(SanitizerKind::Bool);
bool HasEnumCheck = SanOpts.has(SanitizerKind::Enum);
if (!HasBoolCheck && !HasEnumCheck)
return false;
bool IsBool = hasBooleanRepresentation(Ty) ||
NSAPI(CGM.getContext()).isObjCBOOLType(Ty);
bool NeedsBoolCheck = HasBoolCheck && IsBool;
bool NeedsEnumCheck = HasEnumCheck && Ty->getAs<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;
--End;
if (!Min) {
Check = Builder.CreateICmpULE(Value, llvm::ConstantInt::get(Ctx, End));
} else {
llvm::Value *Upper =
Builder.CreateICmpSLE(Value, llvm::ConstantInt::get(Ctx, End));
llvm::Value *Lower =
Builder.CreateICmpSGE(Value, llvm::ConstantInt::get(Ctx, Min));
Check = Builder.CreateAnd(Upper, Lower);
}
llvm::Constant *StaticArgs[] = {EmitCheckSourceLocation(Loc),
EmitCheckTypeDescriptor(Ty)};
SanitizerMask Kind =
NeedsEnumCheck ? SanitizerKind::Enum : SanitizerKind::Bool;
EmitCheck(std::make_pair(Check, Kind), SanitizerHandler::LoadInvalidValue,
StaticArgs, EmitCheckValue(Value));
return true;
}
llvm::Value *CodeGenFunction::EmitLoadOfScalar(Address Addr, bool Volatile,
QualType Ty,
SourceLocation Loc,
LValueBaseInfo BaseInfo,
TBAAAccessInfo TBAAInfo,
bool isNontemporal) {
if (!CGM.getCodeGenOpts().PreserveVec3Type) {
// For better performance, handle vector loads differently.
if (Ty->isVectorType()) {
const llvm::Type *EltTy = Addr.getElementType();
const auto *VTy = cast<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),
Builder.getInt32(2),
llvm::UndefValue::get(Builder.getInt32Ty())};
llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
Value = Builder.CreateShuffleVector(Value, llvm::UndefValue::get(VecTy),
MaskV, "extractVec");
SrcTy = llvm::VectorType::get(VecTy->getElementType(), 4);
}
if (Addr.getElementType() != SrcTy) {
Addr = Builder.CreateElementBitCast(Addr, SrcTy, "storetmp");
}
}
}
Value = EmitToMemory(Value, Ty);
LValue AtomicLValue =
LValue::MakeAddr(Addr, Ty, getContext(), BaseInfo, TBAAInfo);
if (Ty->isAtomicType() ||
(!isInit && LValueIsSuitableForInlineAtomic(AtomicLValue))) {
EmitAtomicStore(RValue::get(Value), AtomicLValue, isInit);
return;
}
llvm::StoreInst *Store = Builder.CreateStore(Value, Addr, Volatile);
if (isNontemporal) {
llvm::MDNode *Node =
llvm::MDNode::get(Store->getContext(),
llvm::ConstantAsMetadata::get(Builder.getInt32(1)));
Store->setMetadata(CGM.getModule().getMDKindID("nontemporal"), Node);
}
CGM.DecorateInstructionWithTBAA(Store, TBAAInfo);
}
void CodeGenFunction::EmitStoreOfScalar(llvm::Value *value, LValue lvalue,
bool isInit) {
EmitStoreOfScalar(value, lvalue.getAddress(), lvalue.isVolatile(),
lvalue.getType(), lvalue.getBaseInfo(),
lvalue.getTBAAInfo(), isInit, lvalue.isNontemporal());
}
/// EmitLoadOfLValue - Given an expression that represents a value lvalue, this
/// method emits the address of the lvalue, then loads the result as an rvalue,
/// returning the rvalue.
RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, SourceLocation Loc) {
if (LV.isObjCWeak()) {
// load of a __weak object.
Address AddrWeakObj = LV.getAddress();
return RValue::get(CGM.getObjCRuntime().EmitObjCWeakRead(*this,
AddrWeakObj));
}
if (LV.getQuals().getObjCLifetime() == Qualifiers::OCL_Weak) {
// In MRC mode, we do a load+autorelease.
if (!getLangOpts().ObjCAutoRefCount) {
return RValue::get(EmitARCLoadWeak(LV.getAddress()));
}
// In ARC mode, we load retained and then consume the value.
llvm::Value *Object = EmitARCLoadWeakRetained(LV.getAddress());
Object = EmitObjCConsumeObject(LV.getType(), Object);
return RValue::get(Object);
}
if (LV.isSimple()) {
assert(!LV.getType()->isFunctionType());
// Everything needs a load.
return RValue::get(EmitLoadOfScalar(LV, Loc));
}
if (LV.isVectorElt()) {
llvm::LoadInst *Load = Builder.CreateLoad(LV.getVectorAddress(),
LV.isVolatileQualified());
return RValue::get(Builder.CreateExtractElement(Load, LV.getVectorIdx(),
"vecext"));
}
// If this is a reference to a subset of the elements of a vector, either
// shuffle the input or extract/insert them as appropriate.
if (LV.isExtVectorElt())
return EmitLoadOfExtVectorElementLValue(LV);
// Global Register variables always invoke intrinsics
if (LV.isGlobalReg())
return EmitLoadOfGlobalRegLValue(LV);
assert(LV.isBitField() && "Unknown LValue type!");
return EmitLoadOfBitfieldLValue(LV, Loc);
}
RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
SourceLocation Loc) {
const CGBitFieldInfo &Info = LV.getBitFieldInfo();
// Get the output type.
llvm::Type *ResLTy = ConvertType(LV.getType());
Address Ptr = LV.getBitFieldAddress();
llvm::Value *Val = Builder.CreateLoad(Ptr, LV.isVolatileQualified(), "bf.load");
if (Info.IsSigned) {
assert(static_cast<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,
Info.Size),
"bf.clear");
}
Val = Builder.CreateIntCast(Val, ResLTy, Info.IsSigned, "bf.cast");
EmitScalarRangeCheck(Val, LV.getType(), Loc);
return RValue::get(Val);
}
// If this is a reference to a subset of the elements of a vector, create an
// appropriate shufflevector.
RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV) {
llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddress(),
LV.isVolatileQualified());
const llvm::Constant *Elts = LV.getExtVectorElts();
// If the result of the expression is a non-vector type, we must be extracting
// a single element. Just codegen as an extractelement.
const VectorType *ExprVT = LV.getType()->getAs<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()),
MaskV);
return RValue::get(Vec);
}
/// Generates lvalue for partial ext_vector access.
Address CodeGenFunction::EmitExtVectorElementLValue(LValue LV) {
Address VectorAddress = LV.getExtVectorAddress();
const VectorType *ExprVT = LV.getType()->getAs<VectorType>();
QualType EQT = ExprVT->getElementType();
llvm::Type *VectorElementTy = CGM.getTypes().ConvertType(EQT);
Address CastToPointerElement =
Builder.CreateElementBitCast(VectorAddress, VectorElementTy,
"conv.ptr.element");
const llvm::Constant *Elts = LV.getExtVectorElts();
unsigned ix = getAccessedFieldNo(0, Elts);
Address VectorBasePtrPlusIx =
Builder.CreateConstInBoundsGEP(CastToPointerElement, ix,
"vector.elt");
return VectorBasePtrPlusIx;
}
/// Load of global gamed gegisters are always calls to intrinsics.
RValue CodeGenFunction::EmitLoadOfGlobalRegLValue(LValue LV) {
assert((LV.getType()->isIntegerType() || LV.getType()->isPointerType()) &&
"Bad type for register variable");
llvm::MDNode *RegName = cast<llvm::MDNode>(
cast<llvm::MetadataAsValue>(LV.getGlobalReg())->getMetadata());
// We accept integer and pointer types only
llvm::Type *OrigTy = CGM.getTypes().ConvertType(LV.getType());
llvm::Type *Ty = OrigTy;
if (OrigTy->isPointerTy())
Ty = CGM.getTypes().getDataLayout().getIntPtrType(OrigTy);
llvm::Type *Types[] = { Ty };
llvm::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(),
Dst.isVolatileQualified());
Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
Dst.getVectorIdx(), "vecins");
Builder.CreateStore(Vec, Dst.getVectorAddress(),
Dst.isVolatileQualified());
return;
}
// If this is an update of extended vector elements, insert them as
// appropriate.
if (Dst.isExtVectorElt())
return EmitStoreThroughExtVectorComponentLValue(Src, Dst);
if (Dst.isGlobalReg())
return EmitStoreThroughGlobalRegLValue(Src, Dst);
assert(Dst.isBitField() && "Unknown LValue type");
return EmitStoreThroughBitfieldLValue(Src, Dst);
}
// There's special magic for assigning into an ARC-qualified l-value.
if (Qualifiers::ObjCLifetime Lifetime = Dst.getQuals().getObjCLifetime()) {
switch (Lifetime) {
case Qualifiers::OCL_None:
llvm_unreachable("present but none");
case Qualifiers::OCL_ExplicitNone:
// nothing special
break;
case Qualifiers::OCL_Strong:
if (isInit) {
Src = RValue::get(EmitARCRetain(Dst.getType(), Src.getScalarVal()));
break;
}
EmitARCStoreStrong(Dst, Src.getScalarVal(), /*ignore*/ true);
return;
case Qualifiers::OCL_Weak:
if (isInit)
// Initialize and then skip the primitive store.
EmitARCInitWeak(Dst.getAddress(), Src.getScalarVal());
else
EmitARCStoreWeak(Dst.getAddress(), Src.getScalarVal(), /*ignore*/ true);
return;
case Qualifiers::OCL_Autoreleasing:
Src = RValue::get(EmitObjCExtendObjectLifetime(Dst.getType(),
Src.getScalarVal()));
// fall into the normal path
break;
}
}
if (Dst.isObjCWeak() && !Dst.isNonGC()) {
// load of a __weak object.
Address LvalueDst = Dst.getAddress();
llvm::Value *src = Src.getScalarVal();
CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
return;
}
if (Dst.isObjCStrong() && !Dst.isNonGC()) {
// load of a __strong object.
Address LvalueDst = Dst.getAddress();
llvm::Value *src = Src.getScalarVal();
if (Dst.isObjCIvar()) {
assert(Dst.getBaseIvarExp() && "BaseIvarExp is NULL");
llvm::Type *ResultType = IntPtrTy;
Address dst = EmitPointerWithAlignment(Dst.getBaseIvarExp());
llvm::Value *RHS = dst.getPointer();
RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
llvm::Value *LHS =
Builder.CreatePtrToInt(LvalueDst.getPointer(), ResultType,
"sub.ptr.lhs.cast");
llvm::Value *BytesBetween = Builder.CreateSub(LHS, RHS, "ivar.offset");
CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, dst,
BytesBetween);
} else if (Dst.isGlobalObjCRef()) {
CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst,
Dst.isThreadLocalRef());
}
else
CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
return;
}
assert(Src.isScalar() && "Can't emit an agg store with this method");
EmitStoreOfScalar(Src.getScalarVal(), Dst, isInit);
}
void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
llvm::Value **Result) {
const CGBitFieldInfo &Info = Dst.getBitFieldInfo();
llvm::Type *ResLTy = ConvertTypeForMem(Dst.getType());
Address Ptr = Dst.getBitFieldAddress();
// Get the source value, truncated to the width of the bit-field.
llvm::Value *SrcVal = Src.getScalarVal();
// Cast the source to the storage type and shift it into place.
SrcVal = Builder.CreateIntCast(SrcVal, Ptr.getElementType(),
/*isSigned=*/false);
llvm::Value *MaskedVal = SrcVal;
// See if there are other bits in the bitfield's storage we'll need to load
// and mask together with source before storing.
if (Info.StorageSize != Info.Size) {
assert(Info.StorageSize > Info.Size && "Invalid bitfield size.");
llvm::Value *Val =
Builder.CreateLoad(Ptr, Dst.isVolatileQualified(), "bf.load");
// Mask the source value as needed.
if (!hasBooleanRepresentation(Dst.getType()))
SrcVal = Builder.CreateAnd(SrcVal,
llvm::APInt::getLowBitsSet(Info.StorageSize,
Info.Size),
"bf.value");
MaskedVal = SrcVal;
if (Info.Offset)
SrcVal = Builder.CreateShl(SrcVal, Info.Offset, "bf.shl");
// Mask out the original value.
Val = Builder.CreateAnd(Val,
~llvm::APInt::getBitsSet(Info.StorageSize,
Info.Offset,
Info.Offset + Info.Size),
"bf.clear");
// Or together the unchanged values and the source value.
SrcVal = Builder.CreateOr(Val, SrcVal, "bf.set");
} else {
assert(Info.Offset == 0);
}
// Write the new value back out.
Builder.CreateStore(SrcVal, Ptr, Dst.isVolatileQualified());
// Return the new value of the bit-field, if requested.
if (Result) {
llvm::Value *ResultVal = MaskedVal;
// Sign extend the value if needed.
if (Info.IsSigned) {
assert(Info.Size <= Info.StorageSize);
unsigned HighBits = Info.StorageSize - Info.Size;
if (HighBits) {
ResultVal = Builder.CreateShl(ResultVal, HighBits, "bf.result.shl");
ResultVal = Builder.CreateAShr(ResultVal, HighBits, "bf.result.ashr");
}
}
ResultVal = Builder.CreateIntCast(ResultVal, ResLTy, Info.IsSigned,
"bf.result.cast");
*Result = EmitFromMemory(ResultVal, Dst.getType());
}
}
void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
LValue Dst) {
// This access turns into a read/modify/write of the vector. Load the input
// value now.
llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddress(),
Dst.isVolatileQualified());
const llvm::Constant *Elts = Dst.getExtVectorElts();
llvm::Value *SrcVal = Src.getScalarVal();
if (const VectorType *VTy = Dst.getType()->getAs<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,
llvm::UndefValue::get(Vec->getType()),
MaskV);
} else if (NumDstElts > NumSrcElts) {
// Extended the source vector to the same length and then shuffle it
// into the destination.
// FIXME: since we're shuffling with undef, can we just use the indices
// into that? This could be simpler.
SmallVector<llvm::Constant*, 4> ExtMask;
for (unsigned i = 0; i != NumSrcElts; ++i)
ExtMask.push_back(Builder.getInt32(i));
ExtMask.resize(NumDstElts, llvm::UndefValue::get(Int32Ty));
llvm::Value *ExtMaskV = llvm::ConstantVector::get(ExtMask);
llvm::Value *ExtSrcVal =
Builder.CreateShuffleVector(SrcVal,
llvm::UndefValue::get(SrcVal->getType()),
ExtMaskV);
// build identity
SmallVector<llvm::Constant*, 4> Mask;
for (unsigned i = 0; i != NumDstElts; ++i)
Mask.push_back(Builder.getInt32(i));
// When the vector size is odd and .odd or .hi is used, the last element
// of the Elts constant array will be one past the size of the vector.
// Ignore the last element here, if it is greater than the mask size.
if (getAccessedFieldNo(NumSrcElts - 1, Elts) == Mask.size())
NumSrcElts--;
// modify when what gets shuffled in
for (unsigned i = 0; i != NumSrcElts; ++i)
Mask[getAccessedFieldNo(i, Elts)] = Builder.getInt32(i+NumDstElts);
llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV);
} else {
// We should never shorten the vector
llvm_unreachable("unexpected shorten vector length");
}
} else {
// If the Src is a scalar (not a vector) it must be updating one element.
unsigned InIdx = getAccessedFieldNo(0, Elts);
llvm::Value *Elt = llvm::ConstantInt::get(SizeTy, InIdx);
Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt);
}
Builder.CreateStore(Vec, Dst.getExtVectorAddress(),
Dst.isVolatileQualified());
}
/// Store of global named registers are always calls to intrinsics.
void CodeGenFunction::EmitStoreThroughGlobalRegLValue(RValue Src, LValue Dst) {
assert((Dst.getType()->isIntegerType() || Dst.getType()->isPointerType()) &&
"Bad type for register variable");
llvm::MDNode *RegName = cast<llvm::MDNode>(
cast<llvm::MetadataAsValue>(Dst.getGlobalReg())->getMetadata());
assert(RegName && "Register LValue is not metadata");
// We accept integer and pointer types only
llvm::Type *OrigTy = CGM.getTypes().ConvertType(Dst.getType());
llvm::Type *Ty = OrigTy;
if (OrigTy->isPointerTy())
Ty = CGM.getTypes().getDataLayout().getIntPtrType(OrigTy);
llvm::Type *Types[] = { Ty };
llvm::Function *F = CGM.getIntrinsic(llvm::Intrinsic::write_register, Types);
llvm::Value *Value = Src.getScalarVal();
if (OrigTy->isPointerTy())
Value = Builder.CreatePtrToInt(Value, Ty);
Builder.CreateCall(
F, {llvm::MetadataAsValue::get(Ty->getContext(), RegName), Value});
}
// setObjCGCLValueClass - sets class of the lvalue for the purpose of
// generating write-barries API. It is currently a global, ivar,
// or neither.
static void setObjCGCLValueClass(const ASTContext &Ctx, const Expr *E,
LValue &LV,
bool IsMemberAccess=false) {
if (Ctx.getLangOpts().getGC() == LangOptions::NonGC)
return;
if (isa<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()) {
LV.setObjCIvar(false);
return;
}
}
LV.setObjCIvar(true);
auto *Exp = cast<ObjCIvarRefExpr>(const_cast<Expr *>(E));
LV.setBaseIvarExp(Exp->getBase());
LV.setObjCArray(E->getType()->isArrayType());
return;
}
if (const auto *Exp = dyn_cast<DeclRefExpr>(E)) {
if (const auto *VD = dyn_cast<VarDecl>(Exp->getDecl())) {
if (VD->hasGlobalStorage()) {
LV.setGlobalObjCRef(true);
LV.setThreadLocalRef(VD->getTLSKind() != VarDecl::TLS_None);
}
}
LV.setObjCArray(E->getType()->isArrayType());
return;
}
if (const auto *Exp = dyn_cast<UnaryOperator>(E)) {
setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
return;
}
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->getAs<PointerType>()->getPointeeType();
if (ExpTy->isRecordType())
LV.setObjCIvar(false);
}
return;
}
if (const auto *Exp = dyn_cast<GenericSelectionExpr>(E)) {
setObjCGCLValueClass(Ctx, Exp->getResultExpr(), LV);
return;
}
if (const auto *Exp = dyn_cast<ImplicitCastExpr>(E)) {
setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
return;
}
if (const auto *Exp = dyn_cast<CStyleCastExpr>(E)) {
setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
return;
}
if (const auto *Exp = dyn_cast<ObjCBridgedCastExpr>(E)) {
setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
return;
}
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;
LV.setObjCIvar(false);
else if (LV.isGlobalObjCRef() && !LV.isObjCArray())
// Using array syntax to assigning to what global points to is not
// same as assigning to the global itself. {id *G;} G[i] = 0;
LV.setGlobalObjCRef(false);
return;
}
if (const auto *Exp = dyn_cast<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().
LV.setObjCArray(E->getType()->isArrayType());
return;
}
}
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 =
OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(VD);
// 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 &&
!CGF.CGM.getOpenMPRuntime().hasRequiresUnifiedSharedMemory()))
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>());
}
Address
CodeGenFunction::EmitLoadOfReference(LValue RefLVal,
LValueBaseInfo *PointeeBaseInfo,
TBAAAccessInfo *PointeeTBAAInfo) {
llvm::LoadInst *Load = Builder.CreateLoad(RefLVal.getAddress(),
RefLVal.isVolatile());
CGM.DecorateInstructionWithTBAA(Load, RefLVal.getTBAAInfo());
CharUnits Align = getNaturalTypeAlignment(RefLVal.getType()->getPointeeType(),
PointeeBaseInfo, PointeeTBAAInfo,
/* forPointeeType= */ true);
return Address(Load, Align);
}
LValue CodeGenFunction::EmitLoadOfReferenceLValue(LValue RefLVal) {
LValueBaseInfo PointeeBaseInfo;
TBAAAccessInfo PointeeTBAAInfo;
Address PointeeAddr = EmitLoadOfReference(RefLVal, &PointeeBaseInfo,
&PointeeTBAAInfo);
return MakeAddrLValue(PointeeAddr, RefLVal.getType()->getPointeeType(),
PointeeBaseInfo, PointeeTBAAInfo);
}
Address CodeGenFunction::EmitLoadOfPointer(Address Ptr,
const PointerType *PtrTy,
LValueBaseInfo *BaseInfo,
TBAAAccessInfo *TBAAInfo) {
llvm::Value *Addr = Builder.CreateLoad(Ptr);
return Address(Addr, getNaturalTypeAlignment(PtrTy->getPointeeType(),
BaseInfo, TBAAInfo,
/*forPointeeType=*/true));
}
LValue CodeGenFunction::EmitLoadOfPointerLValue(Address PtrAddr,
const PointerType *PtrTy) {
LValueBaseInfo BaseInfo;
TBAAAccessInfo TBAAInfo;
Address Addr = EmitLoadOfPointer(PtrAddr, PtrTy, &BaseInfo, &TBAAInfo);
return MakeAddrLValue(Addr, PtrTy->getPointeeType(), BaseInfo, TBAAInfo);
}
static LValue EmitGlobalVarDeclLValue(CodeGenFunction &CGF,
const Expr *E, const VarDecl *VD) {
QualType T = E->getType();
// If it's thread_local, emit a call to its wrapper function instead.
if (VD->getTLSKind() == VarDecl::TLS_Dynamic &&
CGF.CGM.getCXXABI().usesThreadWrapperFunction())
return CGF.CGM.getCXXABI().EmitThreadLocalVarDeclLValue(CGF, VD, T);
// Check if the variable is marked as declare target with link clause in
// device codegen.
if (CGF.getLangOpts().OpenMPIsDevice) {
Address Addr = 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,
E->getExprLoc());
}
LValue LV = VD->getType()->isReferenceType() ?
CGF.EmitLoadOfReferenceLValue(Addr, VD->getType(),
AlignmentSource::Decl) :
CGF.MakeAddrLValue(Addr, T, AlignmentSource::Decl);
setObjCGCLValueClass(CGF.getContext(), E, LV);
return LV;
}
static llvm::Constant *EmitFunctionDeclPointer(CodeGenModule &CGM,
const FunctionDecl *FD) {
if (FD->hasAttr<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 =
CGM.getContext().getFunctionNoProtoType(Proto->getReturnType());
NoProtoType = CGM.getContext().getPointerType(NoProtoType);
V = llvm::ConstantExpr::getBitCast(V,
CGM.getTypes().ConvertType(NoProtoType));
}
}
return V;
}
static LValue EmitFunctionDeclLValue(CodeGenFunction &CGF,
const Expr *E, const FunctionDecl *FD) {
llvm::Value *V = EmitFunctionDeclPointer(CGF.CGM, FD);
CharUnits Alignment = CGF.getContext().getDeclAlign(FD);
return CGF.MakeAddrLValue(V, E->getType(), Alignment,
AlignmentSource::Decl);
}
static LValue EmitCapturedFieldLValue(CodeGenFunction &CGF, const FieldDecl *FD,
llvm::Value *ThisValue) {
QualType TagType = CGF.getContext().getTagDeclType(FD->getParent());
LValue LV = CGF.MakeNaturalAlignAddrLValue(ThisValue, TagType);
return CGF.EmitLValueForField(LV, FD);
}
/// Named Registers are named metadata pointing to the register name
/// which will be read from/written to as an argument to the intrinsic
/// @llvm.read/write_register.
/// So far, only the name is being passed down, but other options such as
/// register type, allocation type or even optimization options could be
/// passed down via the metadata node.
static LValue EmitGlobalNamedRegister(const VarDecl *VD, CodeGenModule &CGM) {
SmallString<64> Name("llvm.named.register.");
AsmLabelAttr *Asm = VD->getAttr<AsmLabelAttr>();
assert(Asm->getLabel().size() < 64-Name.size() &&
"Register name too big");
Name.append(Asm->getLabel());
llvm::NamedMDNode *M =
CGM.getModule().getOrInsertNamedMetadata(Name);
if (M->getNumOperands() == 0) {
llvm::MDString *Str = llvm::MDString::get(CGM.getLLVMContext(),
Asm->getLabel());
llvm::Metadata *Ops[] = {Str};
M->addOperand(llvm::MDNode::get(CGM.getLLVMContext(), Ops));
}
CharUnits Alignment = CGM.getContext().getDeclAlign(VD);
llvm::Value *Ptr =
llvm::MetadataAsValue::get(CGM.getLLVMContext(), M->getOperand(0));
return LValue::MakeGlobalReg(Address(Ptr, Alignment), VD->getType());
}
/// 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() ==
dyn_cast_or_null<DeclContext>(CGF.CurCodeDecl);
}
// 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;
default:
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))) {
VD->getAnyInitializer(VD);
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,
getContext().getDeclAlign(VD));
} else {
// Should we be using the alignment of the constant pointer we emitted?
CharUnits Alignment =
getNaturalTypeAlignment(E->getType(),
/* 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.
// Check for captured variables.
if (E->refersToEnclosingVariableOrCapture()) {
VD = VD->getCanonicalDecl();
if (auto *FD = LambdaCaptureFields.lookup(VD))
return EmitCapturedFieldLValue(*this, FD, CXXABIThisValue);
else if (CapturedStmtInfo) {
auto I = LocalDeclMap.find(VD);
if (I != LocalDeclMap.end()) {
if (VD->getType()->isReferenceType())
return EmitLoadOfReferenceLValue(I->second, VD->getType(),
AlignmentSource::Decl);
return MakeAddrLValue(I->second, T);
}
LValue CapLVal =
EmitCapturedFieldLValue(*this, CapturedStmtInfo->lookup(VD),
CapturedStmtInfo->getContextValue());
return MakeAddrLValue(
Address(CapLVal.getPointer(), getContext().getDeclAlign(VD)),
CapLVal.getType(), LValueBaseInfo(AlignmentSource::Decl),
CapLVal.getTBAAInfo());
}
assert(isa<BlockDecl>(CurCodeDecl));
Address addr = GetAddrOfBlockDecl(VD);
return MakeAddrLValue(addr, T, AlignmentSource::Decl);
}
}
// FIXME: We should be able to assert this for FunctionDecls as well!
// FIXME: We should be able to assert this for all DeclRefExprs, not just
// those with a valid source location.
assert((ND->isUsed(false) || !isa<VarDecl>(ND) || E->isNonOdrUse() ||
!E->getLocation().isValid()) &&
"Should not use decl without marking it used!");
if (ND->hasAttr<WeakRefAttr>()) {
const auto *VD = cast<ValueDecl>(ND);
ConstantAddress Aliasee = CGM.GetWeakRefReference(VD);
return MakeAddrLValue(Aliasee, T, AlignmentSource::Decl);
}
if (const auto *VD = dyn_cast<VarDecl>(ND)) {
// Check if this is a global variable.
if (VD->hasLinkage() || VD->isStaticDataMember())
return EmitGlobalVarDeclLValue(*this, E, VD);
Address addr = Address::invalid();
// The variable should generally be present in the local decl map.
auto iter = LocalDeclMap.find(VD);
if (iter != LocalDeclMap.end()) {
addr = iter->second;
// Otherwise, it might be static local we haven't emitted yet for
// some reason; most likely, because it's in an outer function.
} else if (VD->isStaticLocal()) {
addr = Address(CGM.getOrCreateStaticVarDecl(
*VD, CGM.getLLVMLinkageVarDefinition(VD, /*IsConstant=*/false)),
getContext().getDeclAlign(VD));
// No other cases for now.
} else {
llvm_unreachable("DeclRefExpr for Decl not entered in LocalDeclMap?");
}
// Check for OpenMP threadprivate variables.
if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd &&
VD->hasAttr<OMPThreadPrivateDeclAttr>()) {
return EmitThreadPrivateVarDeclLValue(
*this, VD, T, addr, getTypes().ConvertTypeForMem(VD->getType()),
E->getExprLoc());
}
// Drill into block byref variables.
bool isBlockByref = VD->isEscapingByref();
if (isBlockByref) {
addr = emitBlockByrefAddress(addr, VD);
}
// Drill into reference types.
LValue LV = VD->getType()->isReferenceType() ?
EmitLoadOfReferenceLValue(addr, VD->getType(), AlignmentSource::Decl) :
MakeAddrLValue(addr, T, AlignmentSource::Decl);
bool isLocalStorage = VD->hasLocalStorage();
bool NonGCable = isLocalStorage &&
!VD->getType()->isReferenceType() &&
!isBlockByref;
if (NonGCable) {
LV.getQuals().removeObjCGCAttr();
LV.setNonGC(true);
}
bool isImpreciseLifetime =
(isLocalStorage && !VD->hasAttr<ObjCPreciseLifetimeAttr>());
if (isImpreciseLifetime)
LV.setARCPreciseLifetime(ARCImpreciseLifetime);
setObjCGCLValueClass(getContext(), E, LV);
return LV;
}
if (const auto *FD = dyn_cast<FunctionDecl>(ND))
return EmitFunctionDeclLValue(*this, E, FD);
// FIXME: While we're emitting a binding from an enclosing scope, all other
// DeclRefExprs we see should be implicitly treated as if they also refer to
// an enclosing scope.
if (const auto *BD = dyn_cast<BindingDecl>(ND))
return EmitLValue(BD->getBinding());
llvm_unreachable("Unhandled DeclRefExpr");
}
LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
// __extension__ doesn't affect lvalue-ness.
if (E->getOpcode() == UO_Extension)
return EmitLValue(E->getSubExpr());
QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
switch (E->getOpcode()) {
default: llvm_unreachable("Unknown unary operator lvalue!");
case UO_Deref: {
QualType T = E->getSubExpr()->getType()->getPointeeType();
assert(!T.isNull() && "CodeGenFunction::EmitUnaryOpLValue: Illegal type");
LValueBaseInfo BaseInfo;
TBAAAccessInfo TBAAInfo;
Address Addr = EmitPointerWithAlignment(E->getSubExpr(), &BaseInfo,
&TBAAInfo);
LValue LV = MakeAddrLValue(Addr, T, BaseInfo, TBAAInfo);
LV.getQuals().setAddressSpace(ExprTy.getAddressSpace());
// We should not generate __weak write barrier on indirect reference
// of a pointer to object; as in void foo (__weak id *param); *param = 0;
// But, we continue to generate __strong write barrier on indirect write
// into a pointer to object.
if (getLangOpts().ObjC &&
getLangOpts().getGC() != LangOptions::NonGC &&
LV.isObjCWeak())
LV.setNonGC(!E->isOBJCGCCandidate(getContext()));
return LV;
}
case UO_Real:
case UO_Imag: {
LValue LV = EmitLValue(E->getSubExpr());
assert(LV.isSimple() && "real/imag on non-ordinary l-value");
// __real is valid on scalars. This is a faster way of testing that.
// __imag can only produce an rvalue on scalars.
if (E->getOpcode() == UO_Real &&
!LV.getAddress().getElementType()->isStructTy()) {
assert(E->getSubExpr()->getType()->isArithmeticType());
return LV;
}
QualType T = ExprTy->castAs<ComplexType>()->getElementType();
Address Component =
(E->getOpcode() == UO_Real
? emitAddrOfRealComponent(LV.getAddress(), LV.getType())
: emitAddrOfImagComponent(LV.getAddress(), LV.getType()));
LValue ElemLV = MakeAddrLValue(Component, T, LV.getBaseInfo(),
CGM.getTBAAInfoForSubobject(LV, T));
ElemLV.getQuals().addQualifiers(LV.getQuals());
return ElemLV;
}
case UO_PreInc:
case UO_PreDec: {
LValue LV = EmitLValue(E->getSubExpr());
bool isInc = E->getOpcode() == UO_PreInc;
if (E->getType()->isAnyComplexType())
EmitComplexPrePostIncDec(E, LV, isInc, true/*isPre*/);
else
EmitScalarPrePostIncDec(E, LV, isInc, true/*isPre*/);
return LV;
}
}
}
LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
return MakeAddrLValue(CGM.GetAddrOfConstantStringFromLiteral(E),
E->getType(), AlignmentSource::Decl);
}
LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
return MakeAddrLValue(CGM.GetAddrOfConstantStringFromObjCEncode(E),
E->getType(), AlignmentSource::Decl);
}
LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
auto SL = E->getFunctionName();
assert(SL != nullptr && "No StringLiteral name in PredefinedExpr");
StringRef FnName = CurFn->getName();
if (FnName.startswith("\01"))
FnName = FnName.substr(1);
StringRef NameItems[] = {
PredefinedExpr::getIdentKindName(E->getIdentKind()), FnName};
std::string GVName = llvm::join(NameItems, NameItems + 2, ".");
if (auto *BD = dyn_cast_or_null<BlockDecl>(CurCodeDecl)) {
std::string Name = SL->getString();
if (!Name.empty()) {
unsigned Discriminator =
CGM.getCXXABI().getMangleContext().getBlockId(BD, true);
if (Discriminator)
Name += "_" + Twine(Discriminator + 1).str();
auto C = CGM.GetAddrOfConstantCString(Name, GVName.c_str());
return MakeAddrLValue(C, E->getType(), AlignmentSource::Decl);
} else {
auto C = CGM.GetAddrOfConstantCString(FnName, GVName.c_str());
return MakeAddrLValue(C, E->getType(), AlignmentSource::Decl);
}
}
auto C = CGM.GetAddrOfConstantStringFromLiteral(SL, GVName);
return MakeAddrLValue(C, E->getType(), AlignmentSource::Decl);
}
/// Emit a type description suitable for use by a runtime sanitizer library. The
/// format of a type descriptor is
///
/// \code
/// { i16 TypeKind, i16 TypeInfo }
/// \endcode
///
/// followed by an array of i8 containing the type name. TypeKind is 0 for an
/// integer, 1 for a floating point value, and -1 for anything else.
llvm::Constant *CodeGenFunction::EmitCheckTypeDescriptor(QualType T) {
// Only emit each type's descriptor once.
if (llvm::Constant *C = CGM.getTypeDescriptorFromMap(T))
return C;
uint16_t TypeKind = -1;
uint16_t TypeInfo = 0;
if (T->isIntegerType()) {
TypeKind = 0;
TypeInfo = (llvm::Log2_32(getContext().getTypeSize(T)) << 1) |
(T->isSignedIntegerType() ? 1 : 0);
} else if (T->isFloatingType()) {
TypeKind = 1;
TypeInfo = getContext().getTypeSize(T);
}
// Format the type name as if for a diagnostic, including quotes and
// optionally an 'aka'.
SmallString<32> Buffer;
CGM.getDiags().ConvertArgToString(DiagnosticsEngine::ak_qualtype,
(intptr_t)T.getAsOpaquePtr(),
StringRef(), StringRef(), None, Buffer,
None);
llvm::Constant *Components[] = {
Builder.getInt16(TypeKind), Builder.getInt16(TypeInfo),
llvm::ConstantDataArray::getString(getLLVMContext(), Buffer)
};
llvm::Constant *Descriptor = llvm::ConstantStruct::getAnon(Components);
auto *GV = new llvm::GlobalVariable(
CGM.getModule(), Descriptor->getType(),
/*isConstant=*/true, llvm::GlobalVariable::PrivateLinkage, Descriptor);
GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
CGM.getSanitizerMetadata()->disableSanitizerForGlobal(GV);
// Remember the descriptor for this type.
CGM.setTypeDescriptorInMap(T, GV);
return GV;
}
llvm::Value *CodeGenFunction::EmitCheckValue(llvm::Value *V) {
llvm::Type *TargetTy = IntPtrTy;
if (V->getType() == TargetTy)
return V;
// Floating-point types which fit into intptr_t are bitcast to integers
// and then passed directly (after zero-extension, if necessary).
if (V->getType()->isFloatingPointTy()) {
unsigned Bits = V->getType()->getPrimitiveSizeInBits();
if (Bits <= TargetTy->getIntegerBitWidth())
V = Builder.CreateBitCast(V, llvm::Type::getIntNTy(getLLVMContext(),
Bits));
}
// Integers which fit in intptr_t are zero-extended and passed directly.
if (V->getType()->isIntegerTy() &&
V->getType()->getIntegerBitWidth() <= TargetTy->getIntegerBitWidth())
return Builder.CreateZExt(V, TargetTy);
// Pointers are passed directly, everything else is passed by address.
if (!V->getType()->isPointerTy()) {
Address Ptr = CreateDefaultAlignTempAlloca(V->getType());
Builder.CreateStore(V, Ptr);
V = Ptr.getPointer();
}
return Builder.CreatePtrToInt(V, TargetTy);
}
/// Emit a representation of a SourceLocation for passing to a handler
/// in a sanitizer runtime library. The format for this data is:
/// \code
/// struct SourceLocation {
/// const char *Filename;
/// int32_t Line, Column;
/// };
/// \endcode
/// For an invalid SourceLocation, the Filename pointer is null.
llvm::Constant *CodeGenFunction::EmitCheckSourceLocation(SourceLocation Loc) {
llvm::Constant *Filename;
int Line, Column;
PresumedLoc PLoc = getContext().getSourceManager().getPresumedLoc(Loc);
if (PLoc.isValid()) {
StringRef FilenameString = PLoc.getFilename();
int PathComponentsToStrip =
CGM.getCodeGenOpts().EmitCheckPathComponentsToStrip;
if (PathComponentsToStrip < 0) {
assert(PathComponentsToStrip != INT_MIN);
int PathComponentsToKeep = -PathComponentsToStrip;
auto I = llvm::sys::path::rbegin(FilenameString);
auto E = llvm::sys::path::rend(FilenameString);
while (I != E && --PathComponentsToKeep)
++I;
FilenameString = FilenameString.substr(I - E);
} else if (PathComponentsToStrip > 0) {
auto I = llvm::sys::path::begin(FilenameString);
auto E = llvm::sys::path::end(FilenameString);
while (I != E && PathComponentsToStrip--)
++I;
if (I != E)
FilenameString =
FilenameString.substr(I - llvm::sys::path::begin(FilenameString));
else
FilenameString = llvm::sys::path::filename(FilenameString);
}
auto FilenameGV = CGM.GetAddrOfConstantCString(FilenameString, ".src");
CGM.getSanitizerMetadata()->disableSanitizerForGlobal(
cast<llvm::GlobalVariable>(FilenameGV.getPointer()));
Filename = FilenameGV.getPointer();
Line = PLoc.getLine();
Column = PLoc.getColumn();
} else {
Filename = llvm::Constant::getNullValue(Int8PtrTy);
Line = Column = 0;
}
llvm::Constant *Data[] = {Filename, Builder.getInt32(Line),
Builder.getInt32(Column)};
return llvm::ConstantStruct::getAnon(Data);
}
namespace {
/// Specify under what conditions this check can be recovered
enum class CheckRecoverableKind {
/// Always terminate program execution if this check fails.
Unrecoverable,
/// Check supports recovering, runtime has both fatal (noreturn) and
/// non-fatal handlers for this check.
Recoverable,
/// Runtime conditionally aborts, always need to support recovery.
AlwaysRecoverable
};
}
static CheckRecoverableKind getRecoverableKind(SanitizerMask Kind) {
assert(Kind.countPopulation() == 1);
if (Kind == SanitizerKind::Function || Kind == SanitizerKind::Vptr)
return CheckRecoverableKind::AlwaysRecoverable;
else if (Kind == SanitizerKind::Return || Kind == SanitizerKind::Unreachable)
return CheckRecoverableKind::Unrecoverable;
else
return CheckRecoverableKind::Recoverable;
}
namespace {
struct SanitizerHandlerInfo {
char const *const Name;
unsigned Version;
};
}
const SanitizerHandlerInfo SanitizerHandlers[] = {
#define SANITIZER_CHECK(Enum, Name, Version) {#Name, Version},
LIST_SANITIZER_CHECKS
#undef SANITIZER_CHECK
};
static void emitCheckHandlerCall(CodeGenFunction &CGF,
llvm::FunctionType *FnType,
ArrayRef<llvm::Value *> FnArgs,
SanitizerHandler CheckHandler,
CheckRecoverableKind RecoverKind, bool IsFatal,
llvm::BasicBlock *ContBB) {
assert(IsFatal || RecoverKind != CheckRecoverableKind::Unrecoverable);
Optional<ApplyDebugLocation> DL;
if (!CGF.Builder.getCurrentDebugLocation()) {
// Ensure that the call has at least an artificial debug location.
DL.emplace(CGF, SourceLocation());
}
bool NeedsAbortSuffix =
IsFatal && RecoverKind != CheckRecoverableKind::Unrecoverable;
bool MinimalRuntime = CGF.CGM.getCodeGenOpts().SanitizeMinimalRuntime;
const SanitizerHandlerInfo &CheckInfo = SanitizerHandlers[CheckHandler];
const StringRef CheckName = CheckInfo.Name;
std::string FnName = "__ubsan_handle_" + CheckName.str();
if (CheckInfo.Version && !MinimalRuntime)
FnName += "_v" + llvm::utostr(CheckInfo.Version);
if (MinimalRuntime)
FnName += "_minimal";
if (NeedsAbortSuffix)
FnName += "_abort";
bool MayReturn =
!IsFatal || RecoverKind == CheckRecoverableKind::AlwaysRecoverable;
llvm::AttrBuilder B;
if (!MayReturn) {
B.addAttribute(llvm::Attribute::NoReturn)
.addAttribute(llvm::Attribute::NoUnwind);
}
B.addAttribute(llvm::Attribute::UWTable);
llvm::FunctionCallee Fn = CGF.CGM.CreateRuntimeFunction(
FnType, FnName,
llvm::AttributeList::get(CGF.getLLVMContext(),
llvm::AttributeList::FunctionIndex, B),
/*Local=*/true);
llvm::CallInst *HandlerCall = CGF.EmitNounwindRuntimeCall(Fn, FnArgs);
if (!MayReturn) {
HandlerCall->setDoesNotReturn();
CGF.Builder.CreateUnreachable();
} else {
CGF.Builder.CreateBr(ContBB);
}
}
void CodeGenFunction::EmitCheck(
ArrayRef<std::pair<llvm::Value *, SanitizerMask>> Checked,
SanitizerHandler CheckHandler, ArrayRef<llvm::Constant *> StaticArgs,
ArrayRef<llvm::Value *> DynamicArgs) {
assert(IsSanitizerScope);
assert(Checked.size() > 0);
assert(CheckHandler >= 0 &&
size_t(CheckHandler) < llvm::array_lengthof(SanitizerHandlers));
const StringRef CheckName = SanitizerHandlers[CheckHandler].Name;
llvm::Value *FatalCond = nullptr;
llvm::Value *RecoverableCond = nullptr;
llvm::Value *TrapCond = nullptr;
for (int i = 0, n = Checked.size(); i < n; ++i) {
llvm::Value *Check = Checked[i].first;
// -fsanitize-trap= overrides -fsanitize-recover=.
llvm::Value *&Cond =
CGM.getCodeGenOpts().SanitizeTrap.has(Checked[i].second)
? TrapCond
: CGM.getCodeGenOpts().SanitizeRecover.has(Checked[i].second)
? RecoverableCond
: FatalCond;
Cond = Cond ? Builder.CreateAnd(Cond, Check) : Check;
}
if (TrapCond)
EmitTrapCheck(TrapCond);
if (!FatalCond && !RecoverableCond)
return;
llvm::Value *JointCond;
if (FatalCond && RecoverableCond)
JointCond = Builder.CreateAnd(FatalCond, RecoverableCond);
else
JointCond = FatalCond ? FatalCond : RecoverableCond;
assert(JointCond);
CheckRecoverableKind RecoverKind = getRecoverableKind(Checked[0].second);
assert(SanOpts.has(Checked[0].second));
#ifndef NDEBUG
for (int i = 1, n = Checked.size(); i < n; ++i) {
assert(RecoverKind == getRecoverableKind(Checked[i].second) &&
"All recoverable kinds in a single check must be same!");
assert(SanOpts.has(Checked[i].second));
}
#endif
llvm::BasicBlock *Cont = createBasicBlock("cont");
llvm::BasicBlock *Handlers = createBasicBlock("handler." + CheckName);
llvm::Instruction *Branch = Builder.CreateCondBr(JointCond, Cont, Handlers);
// Give hint that we very much don't expect to execute the handler
// Value chosen to match UR_NONTAKEN_WEIGHT, see BranchProbabilityInfo.cpp
llvm::MDBuilder MDHelper(getLLVMContext());
llvm::MDNode *Node = MDHelper.createBranchWeights((1U << 20) - 1, 1);
Branch->setMetadata(llvm::LLVMContext::MD_prof, Node);
EmitBlock(Handlers);
// Handler functions take an i8* pointing to the (handler-specific) static
// information block, followed by a sequence of intptr_t arguments
// representing operand values.
SmallVector<llvm::Value *, 4> Args;
SmallVector<llvm::Type *, 4> ArgTypes;
if (!CGM.getCodeGenOpts().SanitizeMinimalRuntime) {
Args.reserve(DynamicArgs.size() + 1);
ArgTypes.reserve(DynamicArgs.size() + 1);
// Emit handler arguments and create handler function type.
if (!StaticArgs.empty()) {
llvm::Constant *Info = llvm::ConstantStruct::getAnon(StaticArgs);
auto *InfoPtr =
new llvm::GlobalVariable(CGM.getModule(), Info->getType(), false,
llvm::GlobalVariable::PrivateLinkage, Info);
InfoPtr->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
CGM.getSanitizerMetadata()->disableSanitizerForGlobal(InfoPtr);
Args.push_back(Builder.CreateBitCast(InfoPtr, Int8PtrTy));
ArgTypes.push_back(Int8PtrTy);
}
for (size_t i = 0, n = DynamicArgs.size(); i != n; ++i) {
Args.push_back(EmitCheckValue(DynamicArgs[i]));
ArgTypes.push_back(IntPtrTy);
}
}
llvm::FunctionType *FnType =
llvm::FunctionType::get(CGM.VoidTy, ArgTypes, false);
if (!FatalCond || !RecoverableCond) {
// Simple case: we need to generate a single handler call, either
// fatal, or non-fatal.
emitCheckHandlerCall(*this, FnType, Args, CheckHandler, RecoverKind,
(FatalCond != nullptr), Cont);
} else {
// Emit two handler calls: first one for set of unrecoverable checks,
// another one for recoverable.
llvm::BasicBlock *NonFatalHandlerBB =
createBasicBlock("non_fatal." + CheckName);
llvm::BasicBlock *FatalHandlerBB = createBasicBlock("fatal." + CheckName);
Builder.CreateCondBr(FatalCond, NonFatalHandlerBB, FatalHandlerBB);
EmitBlock(FatalHandlerBB);
emitCheckHandlerCall(*this, FnType, Args, CheckHandler, RecoverKind, true,
NonFatalHandlerBB);
EmitBlock(NonFatalHandlerBB);
emitCheckHandlerCall(*this, FnType, Args, CheckHandler, RecoverKind, false,
Cont);
}
EmitBlock(Cont);
}
void CodeGenFunction::EmitCfiSlowPathCheck(
SanitizerMask Kind, llvm::Value *Cond, llvm::ConstantInt *TypeId,
llvm::Value *Ptr, ArrayRef<llvm::Constant *> StaticArgs) {
llvm::BasicBlock *Cont = createBasicBlock("cfi.cont");
llvm::BasicBlock *CheckBB = createBasicBlock("cfi.slowpath");
llvm::BranchInst *BI = Builder.CreateCondBr(Cond, Cont, CheckBB);
llvm::MDBuilder MDHelper(getLLVMContext());
llvm::MDNode *Node = MDHelper.createBranchWeights((1U << 20) - 1, 1);
BI->setMetadata(llvm::LLVMContext::MD_prof, Node);
EmitBlock(CheckBB);
bool WithDiag = !CGM.getCodeGenOpts().SanitizeTrap.has(Kind);
llvm::CallInst *CheckCall;
llvm::FunctionCallee SlowPathFn;
if (WithDiag) {
llvm::Constant *Info = llvm::ConstantStruct::getAnon(StaticArgs);
auto *InfoPtr =
new llvm::GlobalVariable(CGM.getModule(), Info->getType(), false,
llvm::GlobalVariable::PrivateLinkage, Info);
InfoPtr->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
CGM.getSanitizerMetadata()->disableSanitizerForGlobal(InfoPtr);
SlowPathFn = CGM.getModule().getOrInsertFunction(
"__cfi_slowpath_diag",
llvm::FunctionType::get(VoidTy, {Int64Ty, Int8PtrTy, Int8PtrTy},
false));
CheckCall = Builder.CreateCall(
SlowPathFn, {TypeId, Ptr, Builder.CreateBitCast(InfoPtr, Int8PtrTy)});
} else {
SlowPathFn = CGM.getModule().getOrInsertFunction(
"__cfi_slowpath",
llvm::FunctionType::get(VoidTy, {Int64Ty, Int8PtrTy}, false));
CheckCall = Builder.CreateCall(SlowPathFn, {TypeId, Ptr});
}
CGM.setDSOLocal(
cast<llvm::GlobalValue>(SlowPathFn.getCallee()->stripPointerCasts()));
CheckCall->setDoesNotThrow();
EmitBlock(Cont);
}
// Emit a stub for __cfi_check function so that the linker knows about this
// symbol in LTO mode.
void CodeGenFunction::EmitCfiCheckStub() {
llvm::Module *M = &CGM.getModule();
auto &Ctx = M->getContext();
llvm::Function *F = llvm::Function::Create(
llvm::FunctionType::get(VoidTy, {Int64Ty, Int8PtrTy, Int8PtrTy}, false),
llvm::GlobalValue::WeakAnyLinkage, "__cfi_check", M);
CGM.setDSOLocal(F);
llvm::BasicBlock *BB = llvm::BasicBlock::Create(Ctx, "entry", F);
// FIXME: consider emitting an intrinsic call like
// call void @llvm.cfi_check(i64 %0, i8* %1, i8* %2)
// which can be lowered in CrossDSOCFI pass to the actual contents of
// __cfi_check. This would allow inlining of __cfi_check calls.
llvm::CallInst::Create(
llvm::Intrinsic::getDeclaration(M, llvm::Intrinsic::trap), "", BB);
llvm::ReturnInst::Create(Ctx, nullptr, BB);
}
// This function is basically a switch over the CFI failure kind, which is
// extracted from CFICheckFailData (1st function argument). Each case is either
// llvm.trap or a call to one of the two runtime handlers, based on
// -fsanitize-trap and -fsanitize-recover settings. Default case (invalid
// failure kind) traps, but this should really never happen. CFICheckFailData
// can be nullptr if the calling module has -fsanitize-trap behavior for this
// check kind; in this case __cfi_check_fail traps as well.
void CodeGenFunction::EmitCfiCheckFail() {
SanitizerScope SanScope(this);
FunctionArgList Args;
ImplicitParamDecl ArgData(getContext(), getContext().VoidPtrTy,
ImplicitParamDecl::Other);
ImplicitParamDecl ArgAddr(getContext(), getContext().VoidPtrTy,
ImplicitParamDecl::Other);
Args.push_back(&ArgData);
Args.push_back(&ArgAddr);
const CGFunctionInfo &FI =
CGM.getTypes().arrangeBuiltinFunctionDeclaration(getContext().VoidTy, Args);
llvm::Function *F = llvm::Function::Create(
llvm::FunctionType::get(VoidTy, {VoidPtrTy, VoidPtrTy}, false),
llvm::GlobalValue::WeakODRLinkage, "__cfi_check_fail", &CGM.getModule());
F->setVisibility(llvm::GlobalValue::HiddenVisibility);
StartFunction(GlobalDecl(), CGM.getContext().VoidTy, F, FI, Args,
SourceLocation());
// This function should not be affected by blacklist. This function does
// not have a source location, but "src:*" would still apply. Revert any
// changes to SanOpts made in StartFunction.
SanOpts = CGM.getLangOpts().Sanitize;
llvm::Value *Data =
EmitLoadOfScalar(GetAddrOfLocalVar(&ArgData), /*Volatile=*/false,
CGM.getContext().VoidPtrTy, ArgData.getLocation());
llvm::Value *Addr =
EmitLoadOfScalar(GetAddrOfLocalVar(&ArgAddr), /*Volatile=*/false,
CGM.getContext().VoidPtrTy, ArgAddr.getLocation());
// Data == nullptr means the calling module has trap behaviour for this check.
llvm::Value *DataIsNotNullPtr =
Builder.CreateICmpNE(Data, llvm::ConstantPointerNull::get(Int8PtrTy));
EmitTrapCheck(DataIsNotNullPtr);
llvm::StructType *SourceLocationTy =
llvm::StructType::get(VoidPtrTy, Int32Ty, Int32Ty);
llvm::StructType *CfiCheckFailDataTy =
llvm::StructType::get(Int8Ty, SourceLocationTy, VoidPtrTy);
llvm::Value *V = Builder.CreateConstGEP2_32(
CfiCheckFailDataTy,
Builder.CreatePointerCast(Data, CfiCheckFailDataTy->getPointerTo(0)), 0,
0);
Address CheckKindAddr(V, getIntAlign());
llvm::Value *CheckKind = Builder.CreateLoad(CheckKindAddr);
llvm::Value *AllVtables = llvm::MetadataAsValue::get(
CGM.getLLVMContext(),
llvm::MDString::get(CGM.getLLVMContext(), "all-vtables"));
llvm::Value *ValidVtable = Builder.CreateZExt(
Builder.CreateCall(CGM.getIntrinsic(llvm::Intrinsic::type_test),
{Addr, AllVtables}),
IntPtrTy);
const std::pair<int, SanitizerMask> CheckKinds[] = {
{CFITCK_VCall, SanitizerKind::CFIVCall},
{CFITCK_NVCall, SanitizerKind::CFINVCall},
{CFITCK_DerivedCast, SanitizerKind::CFIDerivedCast},
{CFITCK_UnrelatedCast, SanitizerKind::CFIUnrelatedCast},
{CFITCK_ICall, SanitizerKind::CFIICall}};
SmallVector<std::pair<llvm::Value *, SanitizerMask>, 5> Checks;
for (auto CheckKindMaskPair : CheckKinds) {
int Kind = CheckKindMaskPair.first;
SanitizerMask Mask = CheckKindMaskPair.second;
llvm::Value *Cond =
Builder.CreateICmpNE(CheckKind, llvm::ConstantInt::get(Int8Ty, Kind));
if (CGM.getLangOpts().Sanitize.has(Mask))
EmitCheck(std::make_pair(Cond, Mask), SanitizerHandler::CFICheckFail, {},
{Data, Addr, ValidVtable});
else
EmitTrapCheck(Cond);
}
FinishFunction();
// The only reference to this function will be created during LTO link.
// Make sure it survives until then.
CGM.addUsedGlobal(F);
}
void CodeGenFunction::EmitUnreachable(SourceLocation Loc) {
if (SanOpts.has(SanitizerKind::Unreachable)) {
SanitizerScope SanScope(this);
EmitCheck(std::make_pair(static_cast<llvm::Value *>(Builder.getFalse()),
SanitizerKind::Unreachable),
SanitizerHandler::BuiltinUnreachable,
EmitCheckSourceLocation(Loc), None);
}
Builder.CreateUnreachable();
}
void CodeGenFunction::EmitTrapCheck(llvm::Value *Checked) {
llvm::BasicBlock *Cont = createBasicBlock("cont");
// If we're optimizing, collapse all calls to trap down to just one per
// function to save on code size.
if (!CGM.getCodeGenOpts().OptimizationLevel || !TrapBB) {
TrapBB = createBasicBlock("trap");
Builder.CreateCondBr(Checked, Cont, TrapBB);
EmitBlock(TrapBB);
llvm::CallInst *TrapCall = EmitTrapCall(llvm::Intrinsic::trap);
TrapCall->setDoesNotReturn();
TrapCall->setDoesNotThrow();
Builder.CreateUnreachable();
} else {
Builder.CreateCondBr(Checked, Cont, TrapBB);
}
EmitBlock(Cont);
}
llvm::CallInst *CodeGenFunction::EmitTrapCall(llvm::Intrinsic::ID IntrID) {
llvm::CallInst *TrapCall = Builder.CreateCall(CGM.getIntrinsic(IntrID));
if (!CGM.getCodeGenOpts().TrapFuncName.empty()) {
auto A = llvm::Attribute::get(getLLVMContext(), "trap-func-name",
CGM.getCodeGenOpts().TrapFuncName);
TrapCall->addAttribute(llvm::AttributeList::FunctionIndex, A);
}
return TrapCall;
}
Address CodeGenFunction::EmitArrayToPointerDecay(const Expr *E,
LValueBaseInfo *BaseInfo,
TBAAAccessInfo *TBAAInfo) {
assert(E->getType()->isArrayType() &&
"Array to pointer decay must have array source type!");
// Expressions of array type can't be bitfields or vector elements.
LValue LV = EmitLValue(E);
Address Addr = LV.getAddress();
// If the array type was an incomplete type, we need to make sure
// the decay ends up being the right type.
llvm::Type *NewTy = ConvertType(E->getType());
Addr = Builder.CreateElementBitCast(Addr, NewTy);
// Note that VLA pointers are always decayed, so we don't need to do
// anything here.
if (!E->getType()->isVariableArrayType()) {
assert(isa<llvm::ArrayType>(Addr.getElementType()) &&
"Expected pointer to array");
Addr = Builder.CreateConstArrayGEP(Addr, 0, "arraydecay");
}
// The result of this decay conversion points to an array element within the
// base lvalue. However, since TBAA currently does not support representing
// accesses to elements of member arrays, we conservatively represent accesses
// to the pointee object as if it had no any base lvalue specified.
// TODO: Support TBAA for member arrays.
QualType EltType = E->getType()->castAsArrayTypeUnsafe()->getElementType();
if (BaseInfo) *BaseInfo = LV.getBaseInfo();
if (TBAAInfo) *TBAAInfo = CGM.getTBAAAccessInfo(EltType);
return Builder.CreateElementBitCast(Addr, ConvertTypeForMem(EltType));
}
/// isSimpleArrayDecayOperand - If the specified expr is a simple decay from an
/// array to pointer, return the array subexpression.
static const Expr *isSimpleArrayDecayOperand(const Expr *E) {
// If this isn't just an array->pointer decay, bail out.
const auto *CE = dyn_cast<CastExpr>(E);
if (!CE || CE->getCastKind() != CK_ArrayToPointerDecay)
return nullptr;
// If this is a decay from variable width array, bail out.
const Expr *SubExpr = CE->getSubExpr();
if (SubExpr->getType()->isVariableArrayType())
return nullptr;
return SubExpr;
}
static llvm::Value *emitArraySubscriptGEP(CodeGenFunction &CGF,
llvm::Value *ptr,
ArrayRef<llvm::Value*> indices,
bool inbounds,
bool signedIndices,
SourceLocation loc,
const llvm::Twine &name = "arrayidx") {
if (inbounds) {
return CGF.EmitCheckedInBoundsGEP(ptr, indices, signedIndices,
CodeGenFunction::NotSubtraction, loc,
name);
} else {
return CGF.Builder.CreateGEP(ptr, indices, name);
}
}
static CharUnits getArrayElementAlign(CharUnits arrayAlign,
llvm::Value *idx,
CharUnits eltSize) {
// If we have a constant index, we can use the exact offset of the
// element we're accessing.
if (auto constantIdx = dyn_cast<llvm::ConstantInt>(idx)) {
CharUnits offset = constantIdx->getZExtValue() * eltSize;
return arrayAlign.alignmentAtOffset(offset);
// Otherwise, use the worst-case alignment for any element.
} else {
return arrayAlign.alignmentOfArrayElement(eltSize);
}
}
static QualType getFixedSizeElementType(const ASTContext &ctx,
const VariableArrayType *vla) {
QualType eltType;
do {
eltType = vla->getElementType();
} while ((vla = ctx.getAsVariableArrayType(eltType)));
return eltType;
}
static Address emitArraySubscriptGEP(CodeGenFunction &CGF, Address addr,
ArrayRef<llvm::Value *> indices,
QualType eltType, bool inbounds,
bool signedIndices, SourceLocation loc,
QualType *arrayType = nullptr,
const llvm::Twine &name = "arrayidx") {
// All the indices except that last must be zero.
#ifndef NDEBUG
for (auto idx : indices.drop_back())
assert(isa<llvm::ConstantInt>(idx) &&
cast<llvm::ConstantInt>(idx)->isZero());
#endif
// Determine the element size of the statically-sized base. This is
// the thing that the indices are expressed in terms of.
if (auto vla = CGF.getContext().getAsVariableArrayType(eltType)) {
eltType = getFixedSizeElementType(CGF.getContext(), vla);
}
// We can use that to compute the best alignment of the element.
CharUnits eltSize = CGF.getContext().getTypeSizeInChars(eltType);
CharUnits eltAlign =
getArrayElementAlign(addr.getAlignment(), indices.back(), eltSize);
llvm::Value *eltPtr;
auto LastIndex = dyn_cast<llvm::ConstantInt>(indices.back());
if (!CGF.IsInPreservedAIRegion || !LastIndex) {
eltPtr = emitArraySubscriptGEP(
CGF, addr.getPointer(), indices, inbounds, signedIndices,
loc, name);
} else {
// Remember the original array subscript for bpf target
unsigned idx = LastIndex->getZExtValue();
llvm::DIType *DbgInfo = nullptr;
if (arrayType)
DbgInfo = CGF.getDebugInfo()->getOrCreateStandaloneType(*arrayType, loc);
eltPtr = CGF.Builder.CreatePreserveArrayAccessIndex(addr.getPointer(),
indices.size() - 1,
idx, DbgInfo);
}
return Address(eltPtr, eltAlign);
}
LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E,
bool Accessed) {
// The index must always be an integer, which is not an aggregate. Emit it
// in lexical order (this complexity is, sadly, required by C++17).
llvm::Value *IdxPre =
(E->getLHS() == E->getIdx()) ? EmitScalarExpr(E->getIdx()) : nullptr;
bool SignedIndices = false;
auto EmitIdxAfterBase = [&, IdxPre](bool Promote) -> llvm::Value * {
auto *Idx = IdxPre;
if (E->getLHS() != E->getIdx()) {
assert(E->getRHS() == E->getIdx() && "index was neither LHS nor RHS");
Idx = EmitScalarExpr(E->getIdx());
}
QualType IdxTy = E->getIdx()->getType();
bool IdxSigned = IdxTy->isSignedIntegerOrEnumerationType();
SignedIndices |= IdxSigned;
if (SanOpts.has(SanitizerKind::ArrayBounds))
EmitBoundsCheck(E, E->getBase(), Idx, IdxTy, Accessed);
// Extend or truncate the index type to 32 or 64-bits.
if (Promote && Idx->getType() != IntPtrTy)
Idx = Builder.CreateIntCast(Idx, IntPtrTy, IdxSigned, "idxprom");
return Idx;
};
IdxPre = nullptr;
// If the base is a vector type, then we are forming a vector element lvalue
// with this subscript.
if (E->getBase()->getType()->isVectorType() &&
!isa<ExtVectorElementExpr>(E->getBase())) {
// Emit the vector as an lvalue to get its address.
LValue LHS = EmitLValue(E->getBase());
auto *Idx = EmitIdxAfterBase(/*Promote*/false);
assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
return LValue::MakeVectorElt(LHS.getAddress(), Idx, E->getBase()->getType(),
LHS.getBaseInfo(), TBAAAccessInfo());
}
// All the other cases basically behave like simple offsetting.
// Handle the extvector case we ignored above.
if (isa<ExtVectorElementExpr>(E->getBase())) {
LValue LV = EmitLValue(E->getBase());
auto *Idx = EmitIdxAfterBase(/*Promote*/true);
Address Addr = EmitExtVectorElementLValue(LV);
QualType EltType = LV.getType()->castAs<VectorType>()->getElementType();
Addr = emitArraySubscriptGEP(*this, Addr, Idx, EltType, /*inbounds*/ true,
SignedIndices, E->getExprLoc());
return MakeAddrLValue(Addr, EltType, LV.getBaseInfo(),
CGM.getTBAAInfoForSubobject(LV, EltType));
}
LValueBaseInfo EltBaseInfo;
TBAAAccessInfo EltTBAAInfo;
Address Addr = Address::invalid();
if (const VariableArrayType *vla =
getContext().getAsVariableArrayType(E->getType())) {
// The base must be a pointer, which is not an aggregate. Emit
// it. It needs to be emitted first in case it's what captures
// the VLA bounds.
Addr = EmitPointerWithAlignment(E->getBase(), &EltBaseInfo, &EltTBAAInfo);
auto *Idx = EmitIdxAfterBase(/*Promote*/true);
// The element count here is the total number of non-VLA elements.
llvm::Value *numElements = getVLASize(vla).NumElts;
// Effectively, the multiply by the VLA size is part of the GEP.
// GEP indexes are signed, and scaling an index isn't permitted to
// signed-overflow, so we use the same semantics for our explicit
// multiply. We suppress this if overflow is not undefined behavior.
if (getLangOpts().isSignedOverflowDefined()) {
Idx = Builder.CreateMul(Idx, numElements);
} else {
Idx = Builder.CreateNSWMul(Idx, numElements);
}
Addr = emitArraySubscriptGEP(*this, Addr, Idx, vla->getElementType(),
!getLangOpts().isSignedOverflowDefined(),
SignedIndices, E->getExprLoc());
} else if (const ObjCObjectType *OIT = E->getType()->getAs<ObjCObjectType>()){
// Indexing over an interface, as in "NSString *P; P[4];"
// Emit the base pointer.
Addr = EmitPointerWithAlignment(E->getBase(), &EltBaseInfo, &EltTBAAInfo);
auto *Idx = EmitIdxAfterBase(/*Promote*/true);
CharUnits InterfaceSize = getContext().getTypeSizeInChars(OIT);
llvm::Value *InterfaceSizeVal =
llvm::ConstantInt::get(Idx->getType(), InterfaceSize.getQuantity());
llvm::Value *ScaledIdx = Builder.CreateMul(Idx, InterfaceSizeVal);
// We don't necessarily build correct LLVM struct types for ObjC
// interfaces, so we can't rely on GEP to do this scaling
// correctly, so we need to cast to i8*. FIXME: is this actually
// true? A lot of other things in the fragile ABI would break...
llvm::Type *OrigBaseTy = Addr.getType();
Addr = Builder.CreateElementBitCast(Addr, Int8Ty);
// Do the GEP.
CharUnits EltAlign =
getArrayElementAlign(Addr.getAlignment(), Idx, InterfaceSize);
llvm::Value *EltPtr =
emitArraySubscriptGEP(*this, Addr.getPointer(), ScaledIdx, false,
SignedIndices, E->getExprLoc());
Addr = Address(EltPtr, EltAlign);
// Cast back.
Addr = Builder.CreateBitCast(Addr, OrigBaseTy);
} else if (const Expr *Array = isSimpleArrayDecayOperand(E->getBase())) {
// If this is A[i] where A is an array, the frontend will have decayed the
// base to be a ArrayToPointerDecay implicit cast. While correct, it is
// inefficient at -O0 to emit a "gep A, 0, 0" when codegen'ing it, then a
// "gep x, i" here. Emit one "gep A, 0, i".
assert(Array->getType()->isArrayType() &&
"Array to pointer decay must have array source type!");
LValue ArrayLV;
// For simple multidimensional array indexing, set the 'accessed' flag for
// better bounds-checking of the base expression.
if (const auto *ASE = dyn_cast<ArraySubscriptExpr>(Array))
ArrayLV = EmitArraySubscriptExpr(ASE, /*Accessed*/ true);
else
ArrayLV = EmitLValue(Array);
auto *Idx = EmitIdxAfterBase(/*Promote*/true);
// Propagate the alignment from the array itself to the result.
QualType arrayType = Array->getType();
Addr = emitArraySubscriptGEP(
*this, ArrayLV.getAddress(), {CGM.getSize(CharUnits::Zero()), Idx},
E->getType(), !getLangOpts().isSignedOverflowDefined(), SignedIndices,
E->getExprLoc(), &arrayType);
EltBaseInfo = ArrayLV.getBaseInfo();
EltTBAAInfo = CGM.getTBAAInfoForSubobject(ArrayLV, E->getType());
} else {
// The base must be a pointer; emit it with an estimate of its alignment.
Addr = EmitPointerWithAlignment(E->getBase(), &EltBaseInfo, &EltTBAAInfo);
auto *Idx = EmitIdxAfterBase(/*Promote*/true);
QualType ptrType = E->getBase()->getType();
Addr = emitArraySubscriptGEP(*this, Addr, Idx, E->getType(),
!getLangOpts().isSignedOverflowDefined(),
SignedIndices, E->getExprLoc(), &ptrType);
}
LValue LV = MakeAddrLValue(Addr, E->getType(), EltBaseInfo, EltTBAAInfo);
if (getLangOpts().ObjC &&
getLangOpts().getGC() != LangOptions::NonGC) {
LV.setNonGC(!E->isOBJCGCCandidate(getContext()));
setObjCGCLValueClass(getContext(), E, LV);
}
return LV;
}
static Address emitOMPArraySectionBase(CodeGenFunction &CGF, const Expr *Base,
LValueBaseInfo &BaseInfo,
TBAAAccessInfo &TBAAInfo,
QualType BaseTy, QualType ElTy,
bool IsLowerBound) {
LValue BaseLVal;
if (auto *ASE = dyn_cast<OMPArraySectionExpr>(Base->IgnoreParenImpCasts())) {
BaseLVal = CGF.EmitOMPArraySectionExpr(ASE, IsLowerBound);
if (BaseTy->isArrayType()) {
Address Addr = BaseLVal.getAddress();
BaseInfo = BaseLVal.getBaseInfo();
// If the array type was an incomplete type, we need to make sure
// the decay ends up being the right type.
llvm::Type *NewTy = CGF.ConvertType(BaseTy);
Addr = CGF.Builder.CreateElementBitCast(Addr, NewTy);
// Note that VLA pointers are always decayed, so we don't need to do
// anything here.
if (!BaseTy->isVariableArrayType()) {
assert(isa<llvm::ArrayType>(Addr.getElementType()) &&
"Expected pointer to array");
Addr = CGF.Builder.CreateConstArrayGEP(Addr, 0, "arraydecay");
}
return CGF.Builder.CreateElementBitCast(Addr,
CGF.ConvertTypeForMem(ElTy));
}
LValueBaseInfo TypeBaseInfo;
TBAAAccessInfo TypeTBAAInfo;
CharUnits Align = CGF.getNaturalTypeAlignment(ElTy, &TypeBaseInfo,
&TypeTBAAInfo);
BaseInfo.mergeForCast(TypeBaseInfo);
TBAAInfo = CGF.CGM.mergeTBAAInfoForCast(TBAAInfo, TypeTBAAInfo);
return Address(CGF.Builder.CreateLoad(BaseLVal.getAddress()), Align);
}
return CGF.EmitPointerWithAlignment(Base, &BaseInfo, &TBAAInfo);
}
LValue CodeGenFunction::EmitOMPArraySectionExpr(const OMPArraySectionExpr *E,
bool IsLowerBound) {
QualType BaseTy = OMPArraySectionExpr::getBaseOriginalType(E->getBase());
QualType ResultExprTy;
if (auto *AT = getContext().getAsArrayType(BaseTy))
ResultExprTy = AT->getElementType();
else
ResultExprTy = BaseTy->getPointeeType();
llvm::Value *Idx = nullptr;
if (IsLowerBound || E->getColonLoc().isInvalid()) {
// Requesting lower bound or upper bound, but without provided length and
// without ':' symbol for the default length -> length = 1.
// Idx = LowerBound ?: 0;
if (auto *LowerBound = E->getLowerBound()) {
Idx = Builder.CreateIntCast(
EmitScalarExpr(LowerBound), IntPtrTy,
LowerBound->getType()->hasSignedIntegerRepresentation());
} else
Idx = llvm::ConstantInt::getNullValue(IntPtrTy);
} else {
// Try to emit length or lower bound as constant. If this is possible, 1
// is subtracted from constant length or lower bound. Otherwise, emit LLVM
// IR (LB + Len) - 1.
auto &C = CGM.getContext();
auto *Length = E->getLength();
llvm::APSInt ConstLength;
if (Length) {
// Idx = LowerBound + Length - 1;
if (Length->isIntegerConstantExpr(ConstLength, C)) {
ConstLength = ConstLength.zextOrTrunc(PointerWidthInBits);
Length = nullptr;
}
auto *LowerBound = E->getLowerBound();
llvm::APSInt ConstLowerBound(PointerWidthInBits, /*isUnsigned=*/false);
if (LowerBound && LowerBound->isIntegerConstantExpr(ConstLowerBound, C)) {
ConstLowerBound = ConstLowerBound.zextOrTrunc(PointerWidthInBits);
LowerBound = nullptr;
}
if (!Length)
--ConstLength;
else if (!LowerBound)
--ConstLowerBound;
if (Length || LowerBound) {
auto *LowerBoundVal =
LowerBound
? Builder.CreateIntCast(
EmitScalarExpr(LowerBound), IntPtrTy,
LowerBound->getType()->hasSignedIntegerRepresentation())
: llvm::ConstantInt::get(IntPtrTy, ConstLowerBound);
auto *LengthVal =
Length
? Builder.CreateIntCast(
EmitScalarExpr(Length), IntPtrTy,
Length->getType()->hasSignedIntegerRepresentation())
: llvm::ConstantInt::get(IntPtrTy, ConstLength);
Idx = Builder.CreateAdd(LowerBoundVal, LengthVal, "lb_add_len",
/*HasNUW=*/false,
!getLangOpts().isSignedOverflowDefined());
if (Length && LowerBound) {
Idx = Builder.CreateSub(
Idx, llvm::ConstantInt::get(IntPtrTy, /*V=*/1), "idx_sub_1",
/*HasNUW=*/false, !getLangOpts().isSignedOverflowDefined());
}
} else
Idx = llvm::ConstantInt::get(IntPtrTy, ConstLength + ConstLowerBound);
} else {
// Idx = ArraySize - 1;
QualType ArrayTy = BaseTy->isPointerType()
? E->getBase()->IgnoreParenImpCasts()->getType()
: BaseTy;
if (auto *VAT = C.getAsVariableArrayType(ArrayTy)) {
Length = VAT->getSizeExpr();
if (Length->isIntegerConstantExpr(ConstLength, C))
Length = nullptr;
} else {
auto *CAT = C.getAsConstantArrayType(ArrayTy);
ConstLength = CAT->getSize();
}
if (Length) {
auto *LengthVal = Builder.CreateIntCast(
EmitScalarExpr(Length), IntPtrTy,
Length->getType()->hasSignedIntegerRepresentation());
Idx = Builder.CreateSub(
LengthVal, llvm::ConstantInt::get(IntPtrTy, /*V=*/1), "len_sub_1",
/*HasNUW=*/false, !getLangOpts().isSignedOverflowDefined());
} else {
ConstLength = ConstLength.zextOrTrunc(PointerWidthInBits);
--ConstLength;
Idx = llvm::ConstantInt::get(IntPtrTy, ConstLength);
}
}
}
assert(Idx);
Address EltPtr = Address::invalid();
LValueBaseInfo BaseInfo;
TBAAAccessInfo TBAAInfo;
if (auto *VLA = getContext().getAsVariableArrayType(ResultExprTy)) {
// The base must be a pointer, which is not an aggregate. Emit
// it. It needs to be emitted first in case it's what captures
// the VLA bounds.
Address Base =
emitOMPArraySectionBase(*this, E->getBase(), BaseInfo, TBAAInfo,
BaseTy, VLA->getElementType(), IsLowerBound);
// The element count here is the total number of non-VLA elements.
llvm::Value *NumElements = getVLASize(VLA).NumElts;
// Effectively, the multiply by the VLA size is part of the GEP.
// GEP indexes are signed, and scaling an index isn't permitted to
// signed-overflow, so we use the same semantics for our explicit
// multiply. We suppress this if overflow is not undefined behavior.
if (getLangOpts().isSignedOverflowDefined())
Idx = Builder.CreateMul(Idx, NumElements);
else
Idx = Builder.CreateNSWMul(Idx, NumElements);
EltPtr = emitArraySubscriptGEP(*this, Base, Idx, VLA->getElementType(),
!getLangOpts().isSignedOverflowDefined(),
/*signedIndices=*/false, E->getExprLoc());
} else if (const Expr *Array = isSimpleArrayDecayOperand(E->getBase())) {
// If this is A[i] where A is an array, the frontend will have decayed the
// base to be a ArrayToPointerDecay implicit cast. While correct, it is
// inefficient at -O0 to emit a "gep A, 0, 0" when codegen'ing it, then a
// "gep x, i" here. Emit one "gep A, 0, i".
assert(Array->getType()->isArrayType() &&
"Array to pointer decay must have array source type!");
LValue ArrayLV;
// For simple multidimensional array indexing, set the 'accessed' flag for
// better bounds-checking of the base expression.
if (const auto *ASE = dyn_cast<ArraySubscriptExpr>(Array))
ArrayLV = EmitArraySubscriptExpr(ASE, /*Accessed*/ true);
else
ArrayLV = EmitLValue(Array);
// Propagate the alignment from the array itself to the result.
EltPtr = emitArraySubscriptGEP(
*this, ArrayLV.getAddress(), {CGM.getSize(CharUnits::Zero()), Idx},
ResultExprTy, !getLangOpts().isSignedOverflowDefined(),
/*signedIndices=*/false, E->getExprLoc());
BaseInfo = ArrayLV.getBaseInfo();
TBAAInfo = CGM.getTBAAInfoForSubobject(ArrayLV, ResultExprTy);
} else {
Address Base = emitOMPArraySectionBase(*this, E->getBase(), BaseInfo,
TBAAInfo, BaseTy, ResultExprTy,
IsLowerBound);
EltPtr = emitArraySubscriptGEP(*this, Base, Idx, ResultExprTy,
!getLangOpts().isSignedOverflowDefined(),
/*signedIndices=*/false, E->getExprLoc());
}
return MakeAddrLValue(EltPtr, ResultExprTy, BaseInfo, TBAAInfo);
}
LValue CodeGenFunction::
EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
// Emit the base vector as an l-value.
LValue Base;
// ExtVectorElementExpr's base can either be a vector or pointer to vector.
if (E->isArrow()) {
// If it is a pointer to a vector, emit the address and form an lvalue with
// it.
LValueBaseInfo BaseInfo;
TBAAAccessInfo TBAAInfo;
Address Ptr = EmitPointerWithAlignment(E->getBase(), &BaseInfo, &TBAAInfo);
const PointerType *PT = E->getBase()->getType()->getAs<PointerType>();
Base = MakeAddrLValue(Ptr, PT->getPointeeType(), BaseInfo, TBAAInfo);
Base.getQuals().removeObjCGCAttr();
} else if (E->getBase()->isGLValue()) {
// Otherwise, if the base is an lvalue ( as in the case of foo.x.x),
// emit the base as an lvalue.
assert(E->getBase()->getType()->isVectorType());
Base = EmitLValue(E->getBase());
} else {
// Otherwise, the base is a normal rvalue (as in (V+V).x), emit it as such.
assert(E->getBase()->getType()->isVectorType() &&
"Result must be a vector");
llvm::Value *Vec = EmitScalarExpr(E->getBase());
// Store the vector to memory (because LValue wants an address).
Address VecMem = CreateMemTemp(E->getBase()->getType());
Builder.CreateStore(Vec, VecMem);
Base = MakeAddrLValue(VecMem, E->getBase()->getType(),
AlignmentSource::Decl);
}
QualType type =
E->getType().withCVRQualifiers(Base.getQuals().getCVRQualifiers());
// Encode the element access list into a vector of unsigned indices.
SmallVector<uint32_t, 4> Indices;
E->getEncodedElementAccess(Indices);
if (Base.isSimple()) {
llvm::Constant *CV =
llvm::ConstantDataVector::get(getLLVMContext(), Indices);
return LValue::MakeExtVectorElt(Base.getAddress(), CV, type,
Base.getBaseInfo(), TBAAAccessInfo());
}
assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
llvm::Constant *BaseElts = Base.getExtVectorElts();
SmallVector<llvm::Constant *, 4> CElts;
for (unsigned i = 0, e = Indices.size(); i != e; ++i)
CElts.push_back(BaseElts->getAggregateElement(Indices[i]));
llvm::Constant *CV = llvm::ConstantVector::get(CElts);
return LValue::MakeExtVectorElt(Base.getExtVectorAddress(), CV, type,
Base.getBaseInfo(), TBAAAccessInfo());
}
LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
if (DeclRefExpr *DRE = tryToConvertMemberExprToDeclRefExpr(*this, E)) {
EmitIgnoredExpr(E->getBase());
return EmitDeclRefLValue(DRE);
}
Expr *BaseExpr = E->getBase();
// If this is s.x, emit s as an lvalue. If it is s->x, emit s as a scalar.
LValue BaseLV;
if (E->isArrow()) {
LValueBaseInfo BaseInfo;
TBAAAccessInfo TBAAInfo;
Address Addr = EmitPointerWithAlignment(BaseExpr, &BaseInfo, &TBAAInfo);
QualType PtrTy = BaseExpr->getType()->getPointeeType();
SanitizerSet SkippedChecks;
bool IsBaseCXXThis = IsWrappedCXXThis(BaseExpr);
if (IsBaseCXXThis)
SkippedChecks.set(SanitizerKind::Alignment, true);
if (IsBaseCXXThis || isa<DeclRefExpr>(BaseExpr))
SkippedChecks.set(SanitizerKind::Null, true);
EmitTypeCheck(TCK_MemberAccess, E->getExprLoc(), Addr.getPointer(), PtrTy,
/*Alignment=*/CharUnits::Zero(), SkippedChecks);
BaseLV = MakeAddrLValue(Addr, PtrTy, BaseInfo, TBAAInfo);
} else
BaseLV = EmitCheckedLValue(BaseExpr, TCK_MemberAccess);
NamedDecl *ND = E->getMemberDecl();
if (auto *Field = dyn_cast<FieldDecl>(ND)) {
LValue LV = EmitLValueForField(BaseLV, Field);
setObjCGCLValueClass(getContext(), E, LV);
return LV;
}
if (const auto *FD = dyn_cast<FunctionDecl>(ND))
return EmitFunctionDeclLValue(*this, E, FD);
llvm_unreachable("Unhandled member declaration!");
}
/// Given that we are currently emitting a lambda, emit an l-value for
/// one of its members.
LValue CodeGenFunction::EmitLValueForLambdaField(const FieldDecl *Field) {
assert(cast<CXXMethodDecl>(CurCodeDecl)->getParent()->isLambda());
assert(cast<CXXMethodDecl>(CurCodeDecl)->getParent() == Field->getParent());
QualType LambdaTagType =
getContext().getTagDeclType(Field->getParent());
LValue LambdaLV = MakeNaturalAlignAddrLValue(CXXABIThisValue, LambdaTagType);
return EmitLValueForField(LambdaLV, Field);
}
/// Get the field index in the debug info. The debug info structure/union
/// will ignore the unnamed bitfields.
unsigned CodeGenFunction::getDebugInfoFIndex(const RecordDecl *Rec,
unsigned FieldIndex) {
unsigned I = 0, Skipped = 0;
for (auto F : Rec->getDefinition()->fields()) {
if (I == FieldIndex)
break;
if (F->isUnnamedBitfield())
Skipped++;
I++;
}
return FieldIndex - Skipped;
}
/// Get the address of a zero-sized field within a record. The resulting
/// address doesn't necessarily have the right type.
static Address emitAddrOfZeroSizeField(CodeGenFunction &CGF, Address Base,
const FieldDecl *Field) {
CharUnits Offset = CGF.getContext().toCharUnitsFromBits(
CGF.getContext().getFieldOffset(Field));
if (Offset.isZero())
return Base;
Base = CGF.Builder.CreateElementBitCast(Base, CGF.Int8Ty);
return CGF.Builder.CreateConstInBoundsByteGEP(Base, Offset);
}
/// Drill down to the storage of a field without walking into
/// reference types.
///
/// The resulting address doesn't necessarily have the right type.
static Address emitAddrOfFieldStorage(CodeGenFunction &CGF, Address base,
const FieldDecl *field) {
if (field->isZeroSize(CGF.getContext()))
return emitAddrOfZeroSizeField(CGF, base, field);
const RecordDecl *rec = field->getParent();
unsigned idx =
CGF.CGM.getTypes().getCGRecordLayout(rec).getLLVMFieldNo(field);
return CGF.Builder.CreateStructGEP(base, idx, field->getName());
}
static Address emitPreserveStructAccess(CodeGenFunction &CGF, Address base,
const FieldDecl *field) {
const RecordDecl *rec = field->getParent();
llvm::DIType *DbgInfo = CGF.getDebugInfo()->getOrCreateRecordType(
CGF.getContext().getRecordType(rec), rec->getLocation());
unsigned idx =
CGF.CGM.getTypes().getCGRecordLayout(rec).getLLVMFieldNo(field);
return CGF.Builder.CreatePreserveStructAccessIndex(
base, idx, CGF.getDebugInfoFIndex(rec, field->getFieldIndex()), DbgInfo);
}
static bool hasAnyVptr(const QualType Type, const ASTContext &Context) {
const auto *RD = Type.getTypePtr()->getAsCXXRecordDecl();
if (!RD)
return false;
if (RD->isDynamicClass())
return true;
for (const auto &Base : RD->bases())
if (hasAnyVptr(Base.getType(), Context))
return true;
for (const FieldDecl *Field : RD->fields())
if (hasAnyVptr(Field->getType(), Context))
return true;
return false;
}
LValue CodeGenFunction::EmitLValueForField(LValue base,
const FieldDecl *field) {
LValueBaseInfo BaseInfo = base.getBaseInfo();
if (field->isBitField()) {
const CGRecordLayout &RL =
CGM.getTypes().getCGRecordLayout(field->getParent());
const CGBitFieldInfo &Info = RL.getBitFieldInfo(field);
Address Addr = base.getAddress();
unsigned Idx = RL.getLLVMFieldNo(field);
if (Idx != 0)
// For structs, we GEP to the field that the record layout suggests.
Addr = Builder.CreateStructGEP(Addr, Idx, field->getName());
// Get the access type.
llvm::Type *FieldIntTy =
llvm::Type::getIntNTy(getLLVMContext(), Info.StorageSize);
if (Addr.getElementType() != FieldIntTy)
Addr = Builder.CreateElementBitCast(Addr, FieldIntTy);
QualType fieldType =
field->getType().withCVRQualifiers(base.getVRQualifiers());
// TODO: Support TBAA for bit fields.
LValueBaseInfo FieldBaseInfo(BaseInfo.getAlignmentSource());
return LValue::MakeBitfield(Addr, Info, fieldType, FieldBaseInfo,
TBAAAccessInfo());
}
// Fields of may-alias structures are may-alias themselves.
// FIXME: this should get propagated down through anonymous structs
// and unions.
QualType FieldType = field->getType();
const RecordDecl *rec = field->getParent();
AlignmentSource BaseAlignSource = BaseInfo.getAlignmentSource();
LValueBaseInfo FieldBaseInfo(getFieldAlignmentSource(BaseAlignSource));
TBAAAccessInfo FieldTBAAInfo;
if (base.getTBAAInfo().isMayAlias() ||
rec->hasAttr<MayAliasAttr>() || FieldType->isVectorType()) {
FieldTBAAInfo = TBAAAccessInfo::getMayAliasInfo();
} else if (rec->isUnion()) {
// TODO: Support TBAA for unions.
FieldTBAAInfo = TBAAAccessInfo::getMayAliasInfo();
} else {
// If no base type been assigned for the base access, then try to generate
// one for this base lvalue.
FieldTBAAInfo = base.getTBAAInfo();
if (!FieldTBAAInfo.BaseType) {
FieldTBAAInfo.BaseType = CGM.getTBAABaseTypeInfo(base.getType());
assert(!FieldTBAAInfo.Offset &&
"Nonzero offset for an access with no base type!");
}
// Adjust offset to be relative to the base type.
const ASTRecordLayout &Layout =
getContext().getASTRecordLayout(field->getParent());
unsigned CharWidth = getContext().getCharWidth();
if (FieldTBAAInfo.BaseType)
FieldTBAAInfo.Offset +=
Layout.getFieldOffset(field->getFieldIndex()) / CharWidth;
// Update the final access type and size.
FieldTBAAInfo.AccessType = CGM.getTBAATypeInfo(FieldType);
FieldTBAAInfo.Size =
getContext().getTypeSizeInChars(FieldType).getQuantity();
}
Address addr = base.getAddress();
if (auto *ClassDef = dyn_cast<CXXRecordDecl>(rec)) {
if (CGM.getCodeGenOpts().StrictVTablePointers &&
ClassDef->isDynamicClass()) {
// Getting to any field of dynamic object requires stripping dynamic
// information provided by invariant.group. This is because accessing
// fields may leak the real address of dynamic object, which could result
// in miscompilation when leaked pointer would be compared.
auto *stripped = Builder.CreateStripInvariantGroup(addr.getPointer());
addr = Address(stripped, addr.getAlignment());
}
}
unsigned RecordCVR = base.getVRQualifiers();
if (rec->isUnion()) {
// For unions, there is no pointer adjustment.
assert(!FieldType->isReferenceType() && "union has reference member");
if (CGM.getCodeGenOpts().StrictVTablePointers &&
hasAnyVptr(FieldType, getContext()))
// Because unions can easily skip invariant.barriers, we need to add
// a barrier every time CXXRecord field with vptr is referenced.
addr = Address(Builder.CreateLaunderInvariantGroup(addr.getPointer()),
addr.getAlignment());
if (IsInPreservedAIRegion) {
// Remember the original union field index
llvm::DIType *DbgInfo = getDebugInfo()->getOrCreateRecordType(
getContext().getRecordType(rec), rec->getLocation());
addr = Address(
Builder.CreatePreserveUnionAccessIndex(
addr.getPointer(), getDebugInfoFIndex(rec, field->getFieldIndex()), DbgInfo),
addr.getAlignment());
}
} else {
if (!IsInPreservedAIRegion)
// For structs, we GEP to the field that the record layout suggests.
addr = emitAddrOfFieldStorage(*this, addr, field);
else
// Remember the original struct field index
addr = emitPreserveStructAccess(*this, addr, field);
// If this is a reference field, load the reference right now.
if (FieldType->isReferenceType()) {
LValue RefLVal = MakeAddrLValue(addr, FieldType, FieldBaseInfo,
FieldTBAAInfo);
if (RecordCVR & Qualifiers::Volatile)
RefLVal.getQuals().addVolatile();
addr = EmitLoadOfReference(RefLVal, &FieldBaseInfo, &FieldTBAAInfo);
// Qualifiers on the struct don't apply to the referencee.
RecordCVR = 0;
FieldType = FieldType->getPointeeType();
}
}
// Make sure that the address is pointing to the right type. This is critical
// for both unions and structs. A union needs a bitcast, a struct element
// will need a bitcast if the LLVM type laid out doesn't match the desired
// type.
addr = Builder.CreateElementBitCast(
addr, CGM.getTypes().ConvertTypeForMem(FieldType), field->getName());
if (field->hasAttr<AnnotateAttr>())
addr = EmitFieldAnnotations(field, addr);
LValue LV = MakeAddrLValue(addr, FieldType, FieldBaseInfo, FieldTBAAInfo);
LV.getQuals().addCVRQualifiers(RecordCVR);
// __weak attribute on a field is ignored.
if (LV.getQuals().getObjCGCAttr() == Qualifiers::Weak)
LV.getQuals().removeObjCGCAttr();
return LV;
}
LValue
CodeGenFunction::EmitLValueForFieldInitialization(LValue Base,
const FieldDecl *Field) {
QualType FieldType = Field->getType();
if (!FieldType->isReferenceType())
return EmitLValueForField(Base, Field);
Address V = emitAddrOfFieldStorage(*this, Base.getAddress(), Field);
// Make sure that the address is pointing to the right type.
llvm::Type *llvmType = ConvertTypeForMem(FieldType);
V = Builder.CreateElementBitCast(V, llvmType, Field->getName());
// TODO: Generate TBAA information that describes this access as a structure
// member access and not just an access to an object of the field's type. This
// should be similar to what we do in EmitLValueForField().
LValueBaseInfo BaseInfo = Base.getBaseInfo();
AlignmentSource FieldAlignSource = BaseInfo.getAlignmentSource();
LValueBaseInfo FieldBaseInfo(getFieldAlignmentSource(FieldAlignSource));
return MakeAddrLValue(V, FieldType, FieldBaseInfo,
CGM.getTBAAInfoForSubobject(Base, FieldType));
}
LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr *E){
if (E->isFileScope()) {
ConstantAddress GlobalPtr = CGM.GetAddrOfConstantCompoundLiteral(E);
return MakeAddrLValue(GlobalPtr, E->getType(), AlignmentSource::Decl);
}
if (E->getType()->isVariablyModifiedType())
// make sure to emit the VLA size.
EmitVariablyModifiedType(E->getType());
Address DeclPtr = CreateMemTemp(E->getType(), ".compoundliteral");
const Expr *InitExpr = E->getInitializer();
LValue Result = MakeAddrLValue(DeclPtr, E->getType(), AlignmentSource::Decl);
EmitAnyExprToMem(InitExpr, DeclPtr, E->getType().getQualifiers(),
/*Init*/ true);
return Result;
}
LValue CodeGenFunction::EmitInitListLValue(const InitListExpr *E) {
if (!E->isGLValue())
// Initializing an aggregate temporary in C++11: T{...}.
return EmitAggExprToLValue(E);
// An lvalue initializer list must be initializing a reference.
assert(E->isTransparent() && "non-transparent glvalue init list");
return EmitLValue(E->getInit(0));
}
/// Emit the operand of a glvalue conditional operator. This is either a glvalue
/// or a (possibly-parenthesized) throw-expression. If this is a throw, no
/// LValue is returned and the current block has been terminated.
static Optional<LValue> EmitLValueOrThrowExpression(CodeGenFunction &CGF,
const Expr *Operand) {
if (auto *ThrowExpr = dyn_cast<CXXThrowExpr>(Operand->IgnoreParens())) {
CGF.EmitCXXThrowExpr(ThrowExpr, /*KeepInsertionPoint*/false);
return None;
}
return CGF.EmitLValue(Operand);
}
LValue CodeGenFunction::
EmitConditionalOperatorLValue(const AbstractConditionalOperator *expr) {
if (!expr->isGLValue()) {
// ?: here should be an aggregate.
assert(hasAggregateEvaluationKind(expr->getType()) &&
"Unexpected conditional operator!");
return EmitAggExprToLValue(expr);
}
OpaqueValueMapping binding(*this, expr);
const Expr *condExpr = expr->getCond();
bool CondExprBool;
if (ConstantFoldsToSimpleInteger(condExpr, CondExprBool)) {
const Expr *live = expr->getTrueExpr(), *dead = expr->getFalseExpr();
if (!CondExprBool) std::swap(live, dead);
if (!ContainsLabel(dead)) {
// If the true case is live, we need to track its region.
if (CondExprBool)
incrementProfileCounter(expr);
return EmitLValue(live);
}
}
llvm::BasicBlock *lhsBlock = createBasicBlock("cond.true");
llvm::BasicBlock *rhsBlock = createBasicBlock("cond.false");
llvm::BasicBlock *contBlock = createBasicBlock("cond.end");
ConditionalEvaluation eval(*this);
EmitBranchOnBoolExpr(condExpr, lhsBlock, rhsBlock, getProfileCount(expr));
// Any temporaries created here are conditional.
EmitBlock(lhsBlock);
incrementProfileCounter(expr);
eval.begin(*this);
Optional<LValue> lhs =
EmitLValueOrThrowExpression(*this, expr->getTrueExpr());
eval.end(*this);
if (lhs && !lhs->isSimple())
return EmitUnsupportedLValue(expr, "conditional operator");
lhsBlock = Builder.GetInsertBlock();
if (lhs)
Builder.CreateBr(contBlock);
// Any temporaries created here are conditional.
EmitBlock(rhsBlock);
eval.begin(*this);
Optional<LValue> rhs =
EmitLValueOrThrowExpression(*this, expr->getFalseExpr());
eval.end(*this);
if (rhs && !rhs->isSimple())
return EmitUnsupportedLValue(expr, "conditional operator");
rhsBlock = Builder.GetInsertBlock();
EmitBlock(contBlock);
if (lhs && rhs) {
llvm::PHINode *phi = Builder.CreatePHI(lhs->getPointer()->getType(),
2, "cond-lvalue");
phi->addIncoming(lhs->getPointer(), lhsBlock);
phi->addIncoming(rhs->getPointer(), rhsBlock);
Address result(phi, std::min(lhs->getAlignment(), rhs->getAlignment()));
AlignmentSource alignSource =
std::max(lhs->getBaseInfo().getAlignmentSource(),
rhs->getBaseInfo().getAlignmentSource());
TBAAAccessInfo TBAAInfo = CGM.mergeTBAAInfoForConditionalOperator(
lhs->getTBAAInfo(), rhs->getTBAAInfo());
return MakeAddrLValue(result, expr->getType(), LValueBaseInfo(alignSource),
TBAAInfo);
} else {
assert((lhs || rhs) &&
"both operands of glvalue conditional are throw-expressions?");
return lhs ? *lhs : *rhs;
}
}
/// EmitCastLValue - Casts are never lvalues unless that cast is to a reference
/// type. If the cast is to a reference, we can have the usual lvalue result,
/// otherwise if a cast is needed by the code generator in an lvalue context,
/// then it must mean that we need the address of an aggregate in order to
/// access one of its members. This can happen for all the reasons that casts
/// are permitted with aggregate result, including noop aggregate casts, and
/// cast from scalar to union.
LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
switch (E->getCastKind()) {
case CK_ToVoid:
case CK_BitCast:
case CK_LValueToRValueBitCast:
case CK_ArrayToPointerDecay:
case CK_FunctionToPointerDecay:
case CK_NullToMemberPointer:
case CK_NullToPointer:
case CK_IntegralToPointer:
case CK_PointerToIntegral:
case CK_PointerToBoolean:
case CK_VectorSplat:
case CK_IntegralCast:
case CK_BooleanToSignedIntegral:
case CK_IntegralToBoolean:
case CK_IntegralToFloating:
case CK_FloatingToIntegral:
case CK_FloatingToBoolean:
case CK_FloatingCast:
case CK_FloatingRealToComplex:
case CK_FloatingComplexToReal:
case CK_FloatingComplexToBoolean:
case CK_FloatingComplexCast:
case CK_FloatingComplexToIntegralComplex:
case CK_IntegralRealToComplex:
case CK_IntegralComplexToReal:
case CK_IntegralComplexToBoolean:
case CK_IntegralComplexCast:
case CK_IntegralComplexToFloatingComplex:
case CK_DerivedToBaseMemberPointer:
case CK_BaseToDerivedMemberPointer:
case CK_MemberPointerToBoolean:
case CK_ReinterpretMemberPointer:
case CK_AnyPointerToBlockPointerCast:
case CK_ARCProduceObject:
case CK_ARCConsumeObject:
case CK_ARCReclaimReturnedObject:
case CK_ARCExtendBlockObject:
case CK_CopyAndAutoreleaseBlockObject:
case CK_IntToOCLSampler:
case CK_FixedPointCast:
case CK_FixedPointToBoolean:
case CK_FixedPointToIntegral:
case CK_IntegralToFixedPoint:
return EmitUnsupportedLValue(E, "unexpected cast lvalue");
case CK_Dependent:
llvm_unreachable("dependent cast kind in IR gen!");
case CK_BuiltinFnToFnPtr:
llvm_unreachable("builtin functions are handled elsewhere");
// These are never l-values; just use the aggregate emission code.
case CK_NonAtomicToAtomic:
case CK_AtomicToNonAtomic:
return EmitAggExprToLValue(E);
case CK_Dynamic: {
LValue LV = EmitLValue(E->getSubExpr());
Address V = LV.getAddress();
const auto *DCE = cast<CXXDynamicCastExpr>(E);
return MakeNaturalAlignAddrLValue(EmitDynamicCast(V, DCE), E->getType());
}
case CK_ConstructorConversion:
case CK_UserDefinedConversion:
case CK_CPointerToObjCPointerCast:
case CK_BlockPointerToObjCPointerCast:
case CK_NoOp:
case CK_LValueToRValue:
return EmitLValue(E->getSubExpr());
case CK_UncheckedDerivedToBase:
case CK_DerivedToBase: {
const RecordType *DerivedClassTy =
E->getSubExpr()->getType()->getAs<RecordType>();
auto *DerivedClassDecl = cast<CXXRecordDecl>(DerivedClassTy->getDecl());
LValue LV = EmitLValue(E->getSubExpr());
Address This = LV.getAddress();
// Perform the derived-to-base conversion
Address Base = GetAddressOfBaseClass(
This, DerivedClassDecl, E->path_begin(), E->path_end(),
/*NullCheckValue=*/false, E->getExprLoc());
// TODO: Support accesses to members of base classes in TBAA. For now, we
// conservatively pretend that the complete object is of the base class
// type.
return MakeAddrLValue(Base, E->getType(), LV.getBaseInfo(),
CGM.getTBAAInfoForSubobject(LV, E->getType()));
}
case CK_ToUnion:
return EmitAggExprToLValue(E);
case CK_BaseToDerived: {
const RecordType *DerivedClassTy = E->getType()->getAs<RecordType>();
auto *DerivedClassDecl = cast<CXXRecordDecl>(DerivedClassTy->getDecl());
LValue LV = EmitLValue(E->getSubExpr());
// Perform the base-to-derived conversion
Address Derived =
GetAddressOfDerivedClass(LV.getAddress(), DerivedClassDecl,
E->path_begin(), E->path_end(),
/*NullCheckValue=*/false);
// C++11 [expr.static.cast]p2: Behavior is undefined if a downcast is
// performed and the object is not of the derived type.
if (sanitizePerformTypeCheck())
EmitTypeCheck(TCK_DowncastReference, E->getExprLoc(),
Derived.getPointer(), E->getType());
if (SanOpts.has(SanitizerKind::CFIDerivedCast))
EmitVTablePtrCheckForCast(E->getType(), Derived.getPointer(),
/*MayBeNull=*/false, CFITCK_DerivedCast,
E->getBeginLoc());
return MakeAddrLValue(Derived, E->getType(), LV.getBaseInfo(),
CGM.getTBAAInfoForSubobject(LV, E->getType()));
}
case CK_LValueBitCast: {
// This must be a reinterpret_cast (or c-style equivalent).
const auto *CE = cast<ExplicitCastExpr>(E);
CGM.EmitExplicitCastExprType(CE, this);
LValue LV = EmitLValue(E->getSubExpr());
Address V = Builder.CreateBitCast(LV.getAddress(),
ConvertType(CE->getTypeAsWritten()));
if (SanOpts.has(SanitizerKind::CFIUnrelatedCast))
EmitVTablePtrCheckForCast(E->getType(), V.getPointer(),
/*MayBeNull=*/false, CFITCK_UnrelatedCast,
E->getBeginLoc());
return MakeAddrLValue(V, E->getType(), LV.getBaseInfo(),
CGM.getTBAAInfoForSubobject(LV, E->getType()));
}
case CK_AddressSpaceConversion: {
LValue LV = EmitLValue(E->getSubExpr());
QualType DestTy = getContext().getPointerType(E->getType());
llvm::Value *V = getTargetHooks().performAddrSpaceCast(
*this, LV.getPointer(), E->getSubExpr()->getType().getAddressSpace(),
E->getType().getAddressSpace(), ConvertType(DestTy));
return MakeAddrLValue(Address(V, LV.getAddress().getAlignment()),
E->getType(), LV.getBaseInfo(), LV.getTBAAInfo());
}
case CK_ObjCObjectLValueCast: {
LValue LV = EmitLValue(E->getSubExpr());
Address V = Builder.CreateElementBitCast(LV.getAddress(),
ConvertType(E->getType()));
return MakeAddrLValue(V, E->getType(), LV.getBaseInfo(),
CGM.getTBAAInfoForSubobject(LV, E->getType()));
}
case CK_ZeroToOCLOpaqueType:
llvm_unreachable("NULL to OpenCL opaque type lvalue cast is not valid");
}
llvm_unreachable("Unhandled lvalue cast kind?");
}
LValue CodeGenFunction::EmitOpaqueValueLValue(const OpaqueValueExpr *e) {
assert(OpaqueValueMappingData::shouldBindAsLValue(e));
return getOrCreateOpaqueLValueMapping(e);
}
LValue
CodeGenFunction::getOrCreateOpaqueLValueMapping(const OpaqueValueExpr *e) {
assert(OpaqueValueMapping::shouldBindAsLValue(e));
llvm::DenseMap<const OpaqueValueExpr*,LValue>::iterator
it = OpaqueLValues.find(e);
if (it != OpaqueLValues.end())
return it->second;
assert(e->isUnique() && "LValue for a nonunique OVE hasn't been emitted");
return EmitLValue(e->getSourceExpr());
}
RValue
CodeGenFunction::getOrCreateOpaqueRValueMapping(const OpaqueValueExpr *e) {
assert(!OpaqueValueMapping::shouldBindAsLValue(e));
llvm::DenseMap<const OpaqueValueExpr*,RValue>::iterator
it = OpaqueRValues.find(e);
if (it != OpaqueRValues.end())
return it->second;
assert(e->isUnique() && "RValue for a nonunique OVE hasn't been emitted");
return EmitAnyExpr(e->getSourceExpr());
}
RValue CodeGenFunction::EmitRValueForField(LValue LV,
const FieldDecl *FD,
SourceLocation Loc) {
QualType FT = FD->getType();
LValue FieldLV = EmitLValueForField(LV, FD);
switch (getEvaluationKind(FT)) {
case TEK_Complex:
return RValue::getComplex(EmitLoadOfComplex(FieldLV, Loc));
case TEK_Aggregate:
return FieldLV.asAggregateRValue();
case TEK_Scalar:
// This routine is used to load fields one-by-one to perform a copy, so
// don't load reference fields.
if (FD->getType()->isReferenceType())
return RValue::get(FieldLV.getPointer());
return EmitLoadOfLValue(FieldLV, Loc);
}
llvm_unreachable("bad evaluation kind");
}
//===--------------------------------------------------------------------===//
// Expression Emission
//===--------------------------------------------------------------------===//
RValue CodeGenFunction::EmitCallExpr(const CallExpr *E,
ReturnValueSlot ReturnValue) {
// Builtins never have block type.
if (E->getCallee()->getType()->isBlockPointerType())
return EmitBlockCallExpr(E, ReturnValue);
if (const auto *CE = dyn_cast<CXXMemberCallExpr>(E))
return EmitCXXMemberCallExpr(CE, ReturnValue);
if (const auto *CE = dyn_cast<CUDAKernelCallExpr>(E))
return EmitCUDAKernelCallExpr(CE, ReturnValue);
if (const auto *CE = dyn_cast<CXXOperatorCallExpr>(E))
if (const CXXMethodDecl *MD =
dyn_cast_or_null<CXXMethodDecl>(CE->getCalleeDecl()))
return EmitCXXOperatorMemberCallExpr(CE, MD, ReturnValue);
CGCallee callee = EmitCallee(E->getCallee());
if (callee.isBuiltin()) {
return EmitBuiltinExpr(callee.getBuiltinDecl(), callee.getBuiltinID(),
E, ReturnValue);
}
if (callee.isPseudoDestructor()) {
return EmitCXXPseudoDestructorExpr(callee.getPseudoDestructorExpr());
}
return EmitCall(E->getCallee()->getType(), callee, E, ReturnValue);
}
/// Emit a CallExpr without considering whether it might be a subclass.
RValue CodeGenFunction::EmitSimpleCallExpr(const CallExpr *E,
ReturnValueSlot ReturnValue) {
CGCallee Callee = EmitCallee(E->getCallee());
return EmitCall(E->getCallee()->getType(), Callee, E, ReturnValue);
}
static CGCallee EmitDirectCallee(CodeGenFunction &CGF, const FunctionDecl *FD) {
if (auto builtinID = FD->getBuiltinID()) {
return CGCallee::forBuiltin(builtinID, FD);
}
llvm::Constant *calleePtr = EmitFunctionDeclPointer(CGF.CGM, FD);
return CGCallee::forDirect(calleePtr, GlobalDecl(FD));
}
CGCallee CodeGenFunction::EmitCallee(const Expr *E) {
E = E->IgnoreParens();
// Look through function-to-pointer decay.
if (auto ICE = dyn_cast<ImplicitCastExpr>(E)) {
if (ICE->getCastKind() == CK_FunctionToPointerDecay ||
ICE->getCastKind() == CK_BuiltinFnToFnPtr) {
return EmitCallee(ICE->getSubExpr());
}
// Resolve direct calls.
} else if (auto DRE = dyn_cast<DeclRefExpr>(E)) {
if (auto FD = dyn_cast<FunctionDecl>(DRE->getDecl())) {
return EmitDirectCallee(*this, FD);
}
} else if (auto ME = dyn_cast<MemberExpr>(E)) {
if (auto FD = dyn_cast<FunctionDecl>(ME->getMemberDecl())) {
EmitIgnoredExpr(ME->getBase());
return EmitDirectCallee(*this, FD);
}
// Look through template substitutions.
} else if (auto NTTP = dyn_cast<SubstNonTypeTemplateParmExpr>(E)) {
return EmitCallee(NTTP->getReplacement());
// Treat pseudo-destructor calls differently.
} else if (auto PDE = dyn_cast<CXXPseudoDestructorExpr>(E)) {
return CGCallee::forPseudoDestructor(PDE);
}
// Otherwise, we have an indirect reference.
llvm::Value *calleePtr;
QualType functionType;
if (auto ptrType = E->getType()->getAs<PointerType>()) {
calleePtr = EmitScalarExpr(E);
functionType = ptrType->getPointeeType();
} else {
functionType = E->getType();
calleePtr = EmitLValue(E).getPointer();
}
assert(functionType->isFunctionType());
GlobalDecl GD;
if (const auto *VD =
dyn_cast_or_null<VarDecl>(E->getReferencedDeclOfCallee()))
GD = GlobalDecl(VD);
CGCalleeInfo calleeInfo(functionType->getAs<FunctionProtoType>(), GD);
CGCallee callee(calleeInfo, calleePtr);
return callee;
}
LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
// Comma expressions just emit their LHS then their RHS as an l-value.
if (E->getOpcode() == BO_Comma) {
EmitIgnoredExpr(E->getLHS());
EnsureInsertPoint();
return EmitLValue(E->getRHS());
}
if (E->getOpcode() == BO_PtrMemD ||
E->getOpcode() == BO_PtrMemI)
return EmitPointerToDataMemberBinaryExpr(E);
assert(E->getOpcode() == BO_Assign && "unexpected binary l-value");
// Note that in all of these cases, __block variables need the RHS
// evaluated first just in case the variable gets moved by the RHS.
switch (getEvaluationKind(E->getType())) {
case TEK_Scalar: {
switch (E->getLHS()->getType().getObjCLifetime()) {
case Qualifiers::OCL_Strong:
return EmitARCStoreStrong(E, /*ignored*/ false).first;
case Qualifiers::OCL_Autoreleasing:
return EmitARCStoreAutoreleasing(E).first;
// No reason to do any of these differently.
case Qualifiers::OCL_None:
case Qualifiers::OCL_ExplicitNone:
case Qualifiers::OCL_Weak:
break;
}
RValue RV = EmitAnyExpr(E->getRHS());
LValue LV = EmitCheckedLValue(E->getLHS(), TCK_Store);
if (RV.isScalar())
EmitNullabilityCheck(LV, RV.getScalarVal(), E->getExprLoc());
EmitStoreThroughLValue(RV, LV);
return LV;
}
case TEK_Complex:
return EmitComplexAssignmentLValue(E);
case TEK_Aggregate:
return EmitAggExprToLValue(E);
}
llvm_unreachable("bad evaluation kind");
}
LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
RValue RV = EmitCallExpr(E);
if (!RV.isScalar())
return MakeAddrLValue(RV.getAggregateAddress(), E->getType(),
AlignmentSource::Decl);
assert(E->getCallReturnType(getContext())->isReferenceType() &&
"Can't have a scalar return unless the return type is a "
"reference type!");
return MakeNaturalAlignPointeeAddrLValue(RV.getScalarVal(), E->getType());
}
LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
// FIXME: This shouldn't require another copy.
return EmitAggExprToLValue(E);
}
LValue CodeGenFunction::EmitCXXConstructLValue(const CXXConstructExpr *E) {
assert(E->getType()->getAsCXXRecordDecl()->hasTrivialDestructor()
&& "binding l-value to type which needs a temporary");
AggValueSlot Slot = CreateAggTemp(E->getType());
EmitCXXConstructExpr(E, Slot);
return MakeAddrLValue(Slot.getAddress(), E->getType(), AlignmentSource::Decl);
}
LValue
CodeGenFunction::EmitCXXTypeidLValue(const CXXTypeidExpr *E) {
return MakeNaturalAlignAddrLValue(EmitCXXTypeidExpr(E), E->getType());
}
Address CodeGenFunction::EmitCXXUuidofExpr(const CXXUuidofExpr *E) {
return Builder.CreateElementBitCast(CGM.GetAddrOfUuidDescriptor(E),
ConvertType(E->getType()));
}
LValue CodeGenFunction::EmitCXXUuidofLValue(const CXXUuidofExpr *E) {
return MakeAddrLValue(EmitCXXUuidofExpr(E), E->getType(),
AlignmentSource::Decl);
}
LValue
CodeGenFunction::EmitCXXBindTemporaryLValue(const CXXBindTemporaryExpr *E) {
AggValueSlot Slot = CreateAggTemp(E->getType(), "temp.lvalue");
Slot.setExternallyDestructed();
EmitAggExpr(E->getSubExpr(), Slot);
EmitCXXTemporary(E->getTemporary(), E->getType(), Slot.getAddress());
return MakeAddrLValue(Slot.getAddress(), E->getType(), AlignmentSource::Decl);
}
LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
RValue RV = EmitObjCMessageExpr(E);
if (!RV.isScalar())
return MakeAddrLValue(RV.getAggregateAddress(), E->getType(),
AlignmentSource::Decl);
assert(E->getMethodDecl()->getReturnType()->isReferenceType() &&
"Can't have a scalar return unless the return type is a "
"reference type!");
return MakeNaturalAlignPointeeAddrLValue(RV.getScalarVal(), E->getType());
}
LValue CodeGenFunction::EmitObjCSelectorLValue(const ObjCSelectorExpr *E) {
Address V =
CGM.getObjCRuntime().GetAddrOfSelector(*this, E->getSelector());
return MakeAddrLValue(V, E->getType(), AlignmentSource::Decl);
}
llvm::Value *CodeGenFunction::EmitIvarOffset(const ObjCInterfaceDecl *Interface,
const ObjCIvarDecl *Ivar) {
return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
}
LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
llvm::Value *BaseValue,
const ObjCIvarDecl *Ivar,
unsigned CVRQualifiers) {
return CGM.getObjCRuntime().EmitObjCValueForIvar(*this, ObjectTy, BaseValue,
Ivar, CVRQualifiers);
}
LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
// FIXME: A lot of the code below could be shared with EmitMemberExpr.
llvm::Value *BaseValue = nullptr;
const Expr *BaseExpr = E->getBase();
Qualifiers BaseQuals;
QualType ObjectTy;
if (E->isArrow()) {
BaseValue = EmitScalarExpr(BaseExpr);
ObjectTy = BaseExpr->getType()->getPointeeType();
BaseQuals = ObjectTy.getQualifiers();
} else {
LValue BaseLV = EmitLValue(BaseExpr);
BaseValue = BaseLV.getPointer();
ObjectTy = BaseExpr->getType();
BaseQuals = ObjectTy.getQualifiers();
}
LValue LV =
EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(),
BaseQuals.getCVRQualifiers());
setObjCGCLValueClass(getContext(), E, LV);
return LV;
}
LValue CodeGenFunction::EmitStmtExprLValue(const StmtExpr *E) {
// Can only get l-value for message expression returning aggregate type
RValue RV = EmitAnyExprToTemp(E);
return MakeAddrLValue(RV.getAggregateAddress(), E->getType(),
AlignmentSource::Decl);
}
RValue CodeGenFunction::EmitCall(QualType CalleeType, const CGCallee &OrigCallee,
const CallExpr *E, ReturnValueSlot ReturnValue,
llvm::Value *Chain) {
// Get the actual function type. The callee type will always be a pointer to
// function type or a block pointer type.
assert(CalleeType->isFunctionPointerType() &&
"Call must have function pointer type!");
const Decl *TargetDecl =
OrigCallee.getAbstractInfo().getCalleeDecl().getDecl();
CalleeType = getContext().getCanonicalType(CalleeType);
auto PointeeType = cast<PointerType>(CalleeType)->getPointeeType();
CGCallee Callee = OrigCallee;
if (getLangOpts().CPlusPlus && SanOpts.has(SanitizerKind::Function) &&
(!TargetDecl || !isa<FunctionDecl>(TargetDecl))) {
if (llvm::Constant *PrefixSig =
CGM.getTargetCodeGenInfo().getUBSanFunctionSignature(CGM)) {
SanitizerScope SanScope(this);
// Remove any (C++17) exception specifications, to allow calling e.g. a
// noexcept function through a non-noexcept pointer.
auto ProtoTy =
getContext().getFunctionTypeWithExceptionSpec(PointeeType, EST_None);
llvm::Constant *FTRTTIConst =
CGM.GetAddrOfRTTIDescriptor(ProtoTy, /*ForEH=*/true);
llvm::Type *PrefixStructTyElems[] = {PrefixSig->getType(), Int32Ty};
llvm::StructType *PrefixStructTy = llvm::StructType::get(
CGM.getLLVMContext(), PrefixStructTyElems, /*isPacked=*/true);
llvm::Value *CalleePtr = Callee.getFunctionPointer();
llvm::Value *CalleePrefixStruct = Builder.CreateBitCast(
CalleePtr, llvm::PointerType::getUnqual(PrefixStructTy));
llvm::Value *CalleeSigPtr =
Builder.CreateConstGEP2_32(PrefixStructTy, CalleePrefixStruct, 0, 0);
llvm::Value *CalleeSig =
Builder.CreateAlignedLoad(CalleeSigPtr, getIntAlign());
llvm::Value *CalleeSigMatch = Builder.CreateICmpEQ(CalleeSig, PrefixSig);
llvm::BasicBlock *Cont = createBasicBlock("cont");
llvm::BasicBlock *TypeCheck = createBasicBlock("typecheck");
Builder.CreateCondBr(CalleeSigMatch, TypeCheck, Cont);
EmitBlock(TypeCheck);
llvm::Value *CalleeRTTIPtr =
Builder.CreateConstGEP2_32(PrefixStructTy, CalleePrefixStruct, 0, 1);
llvm::Value *CalleeRTTIEncoded =
Builder.CreateAlignedLoad(CalleeRTTIPtr, getPointerAlign());
llvm::Value *CalleeRTTI =
DecodeAddrUsedInPrologue(CalleePtr, CalleeRTTIEncoded);
llvm::Value *CalleeRTTIMatch =
Builder.CreateICmpEQ(CalleeRTTI, FTRTTIConst);
llvm::Constant *StaticData[] = {EmitCheckSourceLocation(E->getBeginLoc()),
EmitCheckTypeDescriptor(CalleeType)};
EmitCheck(std::make_pair(CalleeRTTIMatch, SanitizerKind::Function),
SanitizerHandler::FunctionTypeMismatch, StaticData,
{CalleePtr, CalleeRTTI, FTRTTIConst});
Builder.CreateBr(Cont);
EmitBlock(Cont);
}
}
const auto *FnType = cast<FunctionType>(PointeeType);
// If we are checking indirect calls and this call is indirect, check that the
// function pointer is a member of the bit set for the function type.
if (SanOpts.has(SanitizerKind::CFIICall) &&
(!TargetDecl || !isa<FunctionDecl>(TargetDecl))) {
SanitizerScope SanScope(this);
EmitSanitizerStatReport(llvm::SanStat_CFI_ICall);
llvm::Metadata *MD;
if (CGM.getCodeGenOpts().SanitizeCfiICallGeneralizePointers)
MD = CGM.CreateMetadataIdentifierGeneralized(QualType(FnType, 0));
else
MD = CGM.CreateMetadataIdentifierForType(QualType(FnType, 0));
llvm::Value *TypeId = llvm::MetadataAsValue::get(getLLVMContext(), MD);
llvm::Value *CalleePtr = Callee.getFunctionPointer();
llvm::Value *CastedCallee = Builder.CreateBitCast(CalleePtr, Int8PtrTy);
llvm::Value *TypeTest = Builder.CreateCall(
CGM.getIntrinsic(llvm::Intrinsic::type_test), {CastedCallee, TypeId});
auto CrossDsoTypeId = CGM.CreateCrossDsoCfiTypeId(MD);
llvm::Constant *StaticData[] = {
llvm::ConstantInt::get(Int8Ty, CFITCK_ICall),
EmitCheckSourceLocation(E->getBeginLoc()),
EmitCheckTypeDescriptor(QualType(FnType, 0)),
};
if (CGM.getCodeGenOpts().SanitizeCfiCrossDso && CrossDsoTypeId) {
EmitCfiSlowPathCheck(SanitizerKind::CFIICall, TypeTest, CrossDsoTypeId,
CastedCallee, StaticData);
} else {
EmitCheck(std::make_pair(TypeTest, SanitizerKind::CFIICall),
SanitizerHandler::CFICheckFail, StaticData,
{CastedCallee, llvm::UndefValue::get(IntPtrTy)});
}
}
CallArgList Args;
if (Chain)
Args.add(RValue::get(Builder.CreateBitCast(Chain, CGM.VoidPtrTy)),
CGM.getContext().VoidPtrTy);
// C++17 requires that we evaluate arguments to a call using assignment syntax
// right-to-left, and that we evaluate arguments to certain other operators
// left-to-right. Note that we allow this to override the order dictated by
// the calling convention on the MS ABI, which means that parameter
// destruction order is not necessarily reverse construction order.
// FIXME: Revisit this based on C++ committee response to unimplementability.
EvaluationOrder Order = EvaluationOrder::Default;
if (auto *OCE = dyn_cast<CXXOperatorCallExpr>(E)) {
if (OCE->isAssignmentOp())
Order = EvaluationOrder::ForceRightToLeft;
else {
switch (OCE->getOperator()) {
case OO_LessLess:
case OO_GreaterGreater:
case OO_AmpAmp:
case OO_PipePipe:
case OO_Comma:
case OO_ArrowStar:
Order = EvaluationOrder::ForceLeftToRight;
break;
default:
break;
}
}
}
EmitCallArgs(Args, dyn_cast<FunctionProtoType>(FnType), E->arguments(),
E->getDirectCallee(), /*ParamsToSkip*/ 0, Order);
const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeFreeFunctionCall(
Args, FnType, /*ChainCall=*/Chain);
// C99 6.5.2.2p6:
// If the expression that denotes the called function has a type
// that does not include a prototype, [the default argument
// promotions are performed]. If the number of arguments does not
// equal the number of parameters, the behavior is undefined. If
// the function is defined with a type that includes a prototype,
// and either the prototype ends with an ellipsis (, ...) or the
// types of the arguments after promotion are not compatible with
// the types of the parameters, the behavior is undefined. If the
// function is defined with a type that does not include a
// prototype, and the types of the arguments after promotion are
// not compatible with those of the parameters after promotion,
// the behavior is undefined [except in some trivial cases].
// That is, in the general case, we should assume that a call
// through an unprototyped function type works like a *non-variadic*
// call. The way we make this work is to cast to the exact type
// of the promoted arguments.
//
// Chain calls use this same code path to add the invisible chain parameter
// to the function type.
if (isa<FunctionNoProtoType>(FnType) || Chain) {
llvm::Type *CalleeTy = getTypes().GetFunctionType(FnInfo);
CalleeTy = CalleeTy->getPointerTo();
llvm::Value *CalleePtr = Callee.getFunctionPointer();
CalleePtr = Builder.CreateBitCast(CalleePtr, CalleeTy, "callee.knr.cast");
Callee.setFunctionPointer(CalleePtr);
}
llvm::CallBase *CallOrInvoke = nullptr;
RValue Call = EmitCall(FnInfo, Callee, ReturnValue, Args, &CallOrInvoke,
E->getExprLoc());
// Generate function declaration DISuprogram in order to be used
// in debug info about call sites.
if (CGDebugInfo *DI = getDebugInfo()) {
if (auto *CalleeDecl = dyn_cast_or_null<FunctionDecl>(TargetDecl))
DI->EmitFuncDeclForCallSite(CallOrInvoke, QualType(FnType, 0),
CalleeDecl);
}
return Call;
}
LValue CodeGenFunction::
EmitPointerToDataMemberBinaryExpr(const BinaryOperator *E) {
Address BaseAddr = Address::invalid();
if (E->getOpcode() == BO_PtrMemI) {
BaseAddr = EmitPointerWithAlignment(E->getLHS());
} else {
BaseAddr = EmitLValue(E->getLHS()).getAddress();
}
llvm::Value *OffsetV = EmitScalarExpr(E->getRHS());
const MemberPointerType *MPT
= E->getRHS()->getType()->getAs<MemberPointerType>();
LValueBaseInfo BaseInfo;
TBAAAccessInfo TBAAInfo;
Address MemberAddr =
EmitCXXMemberDataPointerAddress(E, BaseAddr, OffsetV, MPT, &BaseInfo,
&TBAAInfo);
return MakeAddrLValue(MemberAddr, MPT->getPointeeType(), BaseInfo, TBAAInfo);
}
/// Given the address of a temporary variable, produce an r-value of
/// its type.
RValue CodeGenFunction::convertTempToRValue(Address addr,
QualType type,
SourceLocation loc) {
LValue lvalue = MakeAddrLValue(addr, type, AlignmentSource::Decl);
switch (getEvaluationKind(type)) {
case TEK_Complex:
return RValue::getComplex(EmitLoadOfComplex(lvalue, loc));
case TEK_Aggregate:
return lvalue.asAggregateRValue();
case TEK_Scalar:
return RValue::get(EmitLoadOfScalar(lvalue, loc));
}
llvm_unreachable("bad evaluation kind");
}
void CodeGenFunction::SetFPAccuracy(llvm::Value *Val, float Accuracy) {
assert(Val->getType()->isFPOrFPVectorTy());
if (Accuracy == 0.0 || !isa<llvm::Instruction>(Val))
return;
llvm::MDBuilder MDHelper(getLLVMContext());
llvm::MDNode *Node = MDHelper.createFPMath(Accuracy);
cast<llvm::Instruction>(Val)->setMetadata(llvm::LLVMContext::MD_fpmath, Node);
}
namespace {
struct LValueOrRValue {
LValue LV;
RValue RV;
};
}
static LValueOrRValue emitPseudoObjectExpr(CodeGenFunction &CGF,
const PseudoObjectExpr *E,
bool forLValue,
AggValueSlot slot) {
SmallVector<CodeGenFunction::OpaqueValueMappingData, 4> opaques;
// Find the result expression, if any.
const Expr *resultExpr = E->getResultExpr();
LValueOrRValue result;
for (PseudoObjectExpr::const_semantics_iterator
i = E->semantics_begin(), e = E->semantics_end(); i != e; ++i) {
const Expr *semantic = *i;
// If this semantic expression is an opaque value, bind it
// to the result of its source expression.
if (const auto *ov = dyn_cast<OpaqueValueExpr>(semantic)) {
// Skip unique OVEs.
if (ov->isUnique()) {
assert(ov != resultExpr &&
"A unique OVE cannot be used as the result expression");
continue;
}
// If this is the result expression, we may need to evaluate
// directly into the slot.
typedef CodeGenFunction::OpaqueValueMappingData OVMA;
OVMA opaqueData;
if (ov == resultExpr && ov->isRValue() && !forLValue &&
CodeGenFunction::hasAggregateEvaluationKind(ov->getType())) {
CGF.EmitAggExpr(ov->getSourceExpr(), slot);
LValue LV = CGF.MakeAddrLValue(slot.getAddress(), ov->getType(),
AlignmentSource::Decl);
opaqueData = OVMA::bind(CGF, ov, LV);
result.RV = slot.asRValue();
// Otherwise, emit as normal.
} else {
opaqueData = OVMA::bind(CGF, ov, ov->getSourceExpr());
// If this is the result, also evaluate the result now.
if (ov == resultExpr) {
if (forLValue)
result.LV = CGF.EmitLValue(ov);
else
result.RV = CGF.EmitAnyExpr(ov, slot);
}
}
opaques.push_back(opaqueData);
// Otherwise, if the expression is the result, evaluate it
// and remember the result.
} else if (semantic == resultExpr) {
if (forLValue)
result.LV = CGF.EmitLValue(semantic);
else
result.RV = CGF.EmitAnyExpr(semantic, slot);
// Otherwise, evaluate the expression in an ignored context.
} else {
CGF.EmitIgnoredExpr(semantic);
}
}
// Unbind all the opaques now.
for (unsigned i = 0, e = opaques.size(); i != e; ++i)
opaques[i].unbind(CGF);
return result;
}
RValue CodeGenFunction::EmitPseudoObjectRValue(const PseudoObjectExpr *E,
AggValueSlot slot) {
return emitPseudoObjectExpr(*this, E, false, slot).RV;
}
LValue CodeGenFunction::EmitPseudoObjectLValue(const PseudoObjectExpr *E) {
return emitPseudoObjectExpr(*this, E, true, AggValueSlot::ignored()).LV;
}
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