//===--- CGExprCXX.cpp - Emit LLVM Code for C++ expressions ---------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This contains code dealing with code generation of C++ expressions
//
//===----------------------------------------------------------------------===//
#include "CodeGenFunction.h"
#include "CGCUDARuntime.h"
#include "CGCXXABI.h"
#include "CGDebugInfo.h"
#include "CGObjCRuntime.h"
#include "clang/CodeGen/CGFunctionInfo.h"
#include "clang/Frontend/CodeGenOptions.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/Intrinsics.h"
using namespace clang;
using namespace CodeGen;
static RequiredArgs
commonEmitCXXMemberOrOperatorCall(CodeGenFunction &CGF, const CXXMethodDecl *MD,
llvm::Value *This, llvm::Value *ImplicitParam,
QualType ImplicitParamTy, const CallExpr *CE,
CallArgList &Args) {
assert(CE == nullptr || isa<CXXMemberCallExpr>(CE) ||
isa<CXXOperatorCallExpr>(CE));
assert(MD->isInstance() &&
"Trying to emit a member or operator call expr on a static method!");
// C++11 [class.mfct.non-static]p2:
// If a non-static member function of a class X is called for an object that
// is not of type X, or of a type derived from X, the behavior is undefined.
SourceLocation CallLoc;
if (CE)
CallLoc = CE->getExprLoc();
CGF.EmitTypeCheck(
isa<CXXConstructorDecl>(MD) ? CodeGenFunction::TCK_ConstructorCall
: CodeGenFunction::TCK_MemberCall,
CallLoc, This, CGF.getContext().getRecordType(MD->getParent()));
// Push the this ptr.
Args.add(RValue::get(This), MD->getThisType(CGF.getContext()));
// If there is an implicit parameter (e.g. VTT), emit it.
if (ImplicitParam) {
Args.add(RValue::get(ImplicitParam), ImplicitParamTy);
}
const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, Args.size(), MD);
// And the rest of the call args.
if (CE) {
// Special case: skip first argument of CXXOperatorCall (it is "this").
unsigned ArgsToSkip = isa<CXXOperatorCallExpr>(CE) ? 1 : 0;
CGF.EmitCallArgs(Args, FPT, drop_begin(CE->arguments(), ArgsToSkip),
CE->getDirectCallee());
} else {
assert(
FPT->getNumParams() == 0 &&
"No CallExpr specified for function with non-zero number of arguments");
}
return required;
}
RValue CodeGenFunction::EmitCXXMemberOrOperatorCall(
const CXXMethodDecl *MD, llvm::Value *Callee, ReturnValueSlot ReturnValue,
llvm::Value *This, llvm::Value *ImplicitParam, QualType ImplicitParamTy,
const CallExpr *CE) {
const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
CallArgList Args;
RequiredArgs required = commonEmitCXXMemberOrOperatorCall(
*this, MD, This, ImplicitParam, ImplicitParamTy, CE, Args);
return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required),
Callee, ReturnValue, Args, MD);
}
RValue CodeGenFunction::EmitCXXDestructorCall(
const CXXDestructorDecl *DD, llvm::Value *Callee, llvm::Value *This,
llvm::Value *ImplicitParam, QualType ImplicitParamTy, const CallExpr *CE,
StructorType Type) {
CallArgList Args;
commonEmitCXXMemberOrOperatorCall(*this, DD, This, ImplicitParam,
ImplicitParamTy, CE, Args);
return EmitCall(CGM.getTypes().arrangeCXXStructorDeclaration(DD, Type),
Callee, ReturnValueSlot(), Args, DD);
}
static CXXRecordDecl *getCXXRecord(const Expr *E) {
QualType T = E->getType();
if (const PointerType *PTy = T->getAs<PointerType>())
T = PTy->getPointeeType();
const RecordType *Ty = T->castAs<RecordType>();
return cast<CXXRecordDecl>(Ty->getDecl());
}
// Note: This function also emit constructor calls to support a MSVC
// extensions allowing explicit constructor function call.
RValue CodeGenFunction::EmitCXXMemberCallExpr(const CXXMemberCallExpr *CE,
ReturnValueSlot ReturnValue) {
const Expr *callee = CE->getCallee()->IgnoreParens();
if (isa<BinaryOperator>(callee))
return EmitCXXMemberPointerCallExpr(CE, ReturnValue);
const MemberExpr *ME = cast<MemberExpr>(callee);
const CXXMethodDecl *MD = cast<CXXMethodDecl>(ME->getMemberDecl());
if (MD->isStatic()) {
// The method is static, emit it as we would a regular call.
llvm::Value *Callee = CGM.GetAddrOfFunction(MD);
return EmitCall(getContext().getPointerType(MD->getType()), Callee, CE,
ReturnValue);
}
bool HasQualifier = ME->hasQualifier();
NestedNameSpecifier *Qualifier = HasQualifier ? ME->getQualifier() : nullptr;
bool IsArrow = ME->isArrow();
const Expr *Base = ME->getBase();
return EmitCXXMemberOrOperatorMemberCallExpr(
CE, MD, ReturnValue, HasQualifier, Qualifier, IsArrow, Base);
}
RValue CodeGenFunction::EmitCXXMemberOrOperatorMemberCallExpr(
const CallExpr *CE, const CXXMethodDecl *MD, ReturnValueSlot ReturnValue,
bool HasQualifier, NestedNameSpecifier *Qualifier, bool IsArrow,
const Expr *Base) {
assert(isa<CXXMemberCallExpr>(CE) || isa<CXXOperatorCallExpr>(CE));
// Compute the object pointer.
bool CanUseVirtualCall = MD->isVirtual() && !HasQualifier;
const CXXMethodDecl *DevirtualizedMethod = nullptr;
if (CanUseVirtualCall && CanDevirtualizeMemberFunctionCall(Base, MD)) {
const CXXRecordDecl *BestDynamicDecl = Base->getBestDynamicClassType();
DevirtualizedMethod = MD->getCorrespondingMethodInClass(BestDynamicDecl);
assert(DevirtualizedMethod);
const CXXRecordDecl *DevirtualizedClass = DevirtualizedMethod->getParent();
const Expr *Inner = Base->ignoreParenBaseCasts();
if (DevirtualizedMethod->getReturnType().getCanonicalType() !=
MD->getReturnType().getCanonicalType())
// If the return types are not the same, this might be a case where more
// code needs to run to compensate for it. For example, the derived
// method might return a type that inherits form from the return
// type of MD and has a prefix.
// For now we just avoid devirtualizing these covariant cases.
DevirtualizedMethod = nullptr;
else if (getCXXRecord(Inner) == DevirtualizedClass)
// If the class of the Inner expression is where the dynamic method
// is defined, build the this pointer from it.
Base = Inner;
else if (getCXXRecord(Base) != DevirtualizedClass) {
// If the method is defined in a class that is not the best dynamic
// one or the one of the full expression, we would have to build
// a derived-to-base cast to compute the correct this pointer, but
// we don't have support for that yet, so do a virtual call.
DevirtualizedMethod = nullptr;
}
}
Address This = Address::invalid();
if (IsArrow)
This = EmitPointerWithAlignment(Base);
else
This = EmitLValue(Base).getAddress();
if (MD->isTrivial() || (MD->isDefaulted() && MD->getParent()->isUnion())) {
if (isa<CXXDestructorDecl>(MD)) return RValue::get(nullptr);
if (isa<CXXConstructorDecl>(MD) &&
cast<CXXConstructorDecl>(MD)->isDefaultConstructor())
return RValue::get(nullptr);
if (!MD->getParent()->mayInsertExtraPadding()) {
if (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) {
// We don't like to generate the trivial copy/move assignment operator
// when it isn't necessary; just produce the proper effect here.
// Special case: skip first argument of CXXOperatorCall (it is "this").
unsigned ArgsToSkip = isa<CXXOperatorCallExpr>(CE) ? 1 : 0;
Address RHS = EmitLValue(*(CE->arg_begin() + ArgsToSkip)).getAddress();
EmitAggregateAssign(This, RHS, CE->getType());
return RValue::get(This.getPointer());
}
if (isa<CXXConstructorDecl>(MD) &&
cast<CXXConstructorDecl>(MD)->isCopyOrMoveConstructor()) {
// Trivial move and copy ctor are the same.
assert(CE->getNumArgs() == 1 && "unexpected argcount for trivial ctor");
Address RHS = EmitLValue(*CE->arg_begin()).getAddress();
EmitAggregateCopy(This, RHS, (*CE->arg_begin())->getType());
return RValue::get(This.getPointer());
}
llvm_unreachable("unknown trivial member function");
}
}
// Compute the function type we're calling.
const CXXMethodDecl *CalleeDecl =
DevirtualizedMethod ? DevirtualizedMethod : MD;
const CGFunctionInfo *FInfo = nullptr;
if (const auto *Dtor = dyn_cast<CXXDestructorDecl>(CalleeDecl))
FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
Dtor, StructorType::Complete);
else if (const auto *Ctor = dyn_cast<CXXConstructorDecl>(CalleeDecl))
FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
Ctor, StructorType::Complete);
else
FInfo = &CGM.getTypes().arrangeCXXMethodDeclaration(CalleeDecl);
llvm::FunctionType *Ty = CGM.getTypes().GetFunctionType(*FInfo);
// C++ [class.virtual]p12:
// Explicit qualification with the scope operator (5.1) suppresses the
// virtual call mechanism.
//
// We also don't emit a virtual call if the base expression has a record type
// because then we know what the type is.
bool UseVirtualCall = CanUseVirtualCall && !DevirtualizedMethod;
llvm::Value *Callee;
if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(MD)) {
assert(CE->arg_begin() == CE->arg_end() &&
"Destructor shouldn't have explicit parameters");
assert(ReturnValue.isNull() && "Destructor shouldn't have return value");
if (UseVirtualCall) {
CGM.getCXXABI().EmitVirtualDestructorCall(
*this, Dtor, Dtor_Complete, This, cast<CXXMemberCallExpr>(CE));
} else {
if (getLangOpts().AppleKext && MD->isVirtual() && HasQualifier)
Callee = BuildAppleKextVirtualCall(MD, Qualifier, Ty);
else if (!DevirtualizedMethod)
Callee =
CGM.getAddrOfCXXStructor(Dtor, StructorType::Complete, FInfo, Ty);
else {
const CXXDestructorDecl *DDtor =
cast<CXXDestructorDecl>(DevirtualizedMethod);
Callee = CGM.GetAddrOfFunction(GlobalDecl(DDtor, Dtor_Complete), Ty);
}
EmitCXXMemberOrOperatorCall(MD, Callee, ReturnValue, This.getPointer(),
/*ImplicitParam=*/nullptr, QualType(), CE);
}
return RValue::get(nullptr);
}
if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(MD)) {
Callee = CGM.GetAddrOfFunction(GlobalDecl(Ctor, Ctor_Complete), Ty);
} else if (UseVirtualCall) {
Callee = CGM.getCXXABI().getVirtualFunctionPointer(*this, MD, This, Ty,
CE->getLocStart());
} else {
if (SanOpts.has(SanitizerKind::CFINVCall) &&
MD->getParent()->isDynamicClass()) {
llvm::Value *VTable = GetVTablePtr(This, Int8PtrTy, MD->getParent());
EmitVTablePtrCheckForCall(MD->getParent(), VTable, CFITCK_NVCall,
CE->getLocStart());
}
if (getLangOpts().AppleKext && MD->isVirtual() && HasQualifier)
Callee = BuildAppleKextVirtualCall(MD, Qualifier, Ty);
else if (!DevirtualizedMethod)
Callee = CGM.GetAddrOfFunction(MD, Ty);
else {
Callee = CGM.GetAddrOfFunction(DevirtualizedMethod, Ty);
}
}
if (MD->isVirtual()) {
This = CGM.getCXXABI().adjustThisArgumentForVirtualFunctionCall(
*this, CalleeDecl, This, UseVirtualCall);
}
return EmitCXXMemberOrOperatorCall(MD, Callee, ReturnValue, This.getPointer(),
/*ImplicitParam=*/nullptr, QualType(), CE);
}
RValue
CodeGenFunction::EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr *E,
ReturnValueSlot ReturnValue) {
const BinaryOperator *BO =
cast<BinaryOperator>(E->getCallee()->IgnoreParens());
const Expr *BaseExpr = BO->getLHS();
const Expr *MemFnExpr = BO->getRHS();
const MemberPointerType *MPT =
MemFnExpr->getType()->castAs<MemberPointerType>();
const FunctionProtoType *FPT =
MPT->getPointeeType()->castAs<FunctionProtoType>();
const CXXRecordDecl *RD =
cast<CXXRecordDecl>(MPT->getClass()->getAs<RecordType>()->getDecl());
// Get the member function pointer.
llvm::Value *MemFnPtr = EmitScalarExpr(MemFnExpr);
// Emit the 'this' pointer.
Address This = Address::invalid();
if (BO->getOpcode() == BO_PtrMemI)
This = EmitPointerWithAlignment(BaseExpr);
else
This = EmitLValue(BaseExpr).getAddress();
EmitTypeCheck(TCK_MemberCall, E->getExprLoc(), This.getPointer(),
QualType(MPT->getClass(), 0));
// Ask the ABI to load the callee. Note that This is modified.
llvm::Value *ThisPtrForCall = nullptr;
llvm::Value *Callee =
CGM.getCXXABI().EmitLoadOfMemberFunctionPointer(*this, BO, This,
ThisPtrForCall, MemFnPtr, MPT);
CallArgList Args;
QualType ThisType =
getContext().getPointerType(getContext().getTagDeclType(RD));
// Push the this ptr.
Args.add(RValue::get(ThisPtrForCall), ThisType);
RequiredArgs required =
RequiredArgs::forPrototypePlus(FPT, 1, /*FD=*/nullptr);
// And the rest of the call args
EmitCallArgs(Args, FPT, E->arguments());
return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required),
Callee, ReturnValue, Args);
}
RValue
CodeGenFunction::EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr *E,
const CXXMethodDecl *MD,
ReturnValueSlot ReturnValue) {
assert(MD->isInstance() &&
"Trying to emit a member call expr on a static method!");
return EmitCXXMemberOrOperatorMemberCallExpr(
E, MD, ReturnValue, /*HasQualifier=*/false, /*Qualifier=*/nullptr,
/*IsArrow=*/false, E->getArg(0));
}
RValue CodeGenFunction::EmitCUDAKernelCallExpr(const CUDAKernelCallExpr *E,
ReturnValueSlot ReturnValue) {
return CGM.getCUDARuntime().EmitCUDAKernelCallExpr(*this, E, ReturnValue);
}
static void EmitNullBaseClassInitialization(CodeGenFunction &CGF,
Address DestPtr,
const CXXRecordDecl *Base) {
if (Base->isEmpty())
return;
DestPtr = CGF.Builder.CreateElementBitCast(DestPtr, CGF.Int8Ty);
const ASTRecordLayout &Layout = CGF.getContext().getASTRecordLayout(Base);
CharUnits NVSize = Layout.getNonVirtualSize();
// We cannot simply zero-initialize the entire base sub-object if vbptrs are
// present, they are initialized by the most derived class before calling the
// constructor.
SmallVector<std::pair<CharUnits, CharUnits>, 1> Stores;
Stores.emplace_back(CharUnits::Zero(), NVSize);
// Each store is split by the existence of a vbptr.
CharUnits VBPtrWidth = CGF.getPointerSize();
std::vector<CharUnits> VBPtrOffsets =
CGF.CGM.getCXXABI().getVBPtrOffsets(Base);
for (CharUnits VBPtrOffset : VBPtrOffsets) {
// Stop before we hit any virtual base pointers located in virtual bases.
if (VBPtrOffset >= NVSize)
break;
std::pair<CharUnits, CharUnits> LastStore = Stores.pop_back_val();
CharUnits LastStoreOffset = LastStore.first;
CharUnits LastStoreSize = LastStore.second;
CharUnits SplitBeforeOffset = LastStoreOffset;
CharUnits SplitBeforeSize = VBPtrOffset - SplitBeforeOffset;
assert(!SplitBeforeSize.isNegative() && "negative store size!");
if (!SplitBeforeSize.isZero())
Stores.emplace_back(SplitBeforeOffset, SplitBeforeSize);
CharUnits SplitAfterOffset = VBPtrOffset + VBPtrWidth;
CharUnits SplitAfterSize = LastStoreSize - SplitAfterOffset;
assert(!SplitAfterSize.isNegative() && "negative store size!");
if (!SplitAfterSize.isZero())
Stores.emplace_back(SplitAfterOffset, SplitAfterSize);
}
// If the type contains a pointer to data member we can't memset it to zero.
// Instead, create a null constant and copy it to the destination.
// TODO: there are other patterns besides zero that we can usefully memset,
// like -1, which happens to be the pattern used by member-pointers.
// TODO: isZeroInitializable can be over-conservative in the case where a
// virtual base contains a member pointer.
llvm::Constant *NullConstantForBase = CGF.CGM.EmitNullConstantForBase(Base);
if (!NullConstantForBase->isNullValue()) {
llvm::GlobalVariable *NullVariable = new llvm::GlobalVariable(
CGF.CGM.getModule(), NullConstantForBase->getType(),
/*isConstant=*/true, llvm::GlobalVariable::PrivateLinkage,
NullConstantForBase, Twine());
CharUnits Align = std::max(Layout.getNonVirtualAlignment(),
DestPtr.getAlignment());
NullVariable->setAlignment(Align.getQuantity());
Address SrcPtr = Address(CGF.EmitCastToVoidPtr(NullVariable), Align);
// Get and call the appropriate llvm.memcpy overload.
for (std::pair<CharUnits, CharUnits> Store : Stores) {
CharUnits StoreOffset = Store.first;
CharUnits StoreSize = Store.second;
llvm::Value *StoreSizeVal = CGF.CGM.getSize(StoreSize);
CGF.Builder.CreateMemCpy(
CGF.Builder.CreateConstInBoundsByteGEP(DestPtr, StoreOffset),
CGF.Builder.CreateConstInBoundsByteGEP(SrcPtr, StoreOffset),
StoreSizeVal);
}
// Otherwise, just memset the whole thing to zero. This is legal
// because in LLVM, all default initializers (other than the ones we just
// handled above) are guaranteed to have a bit pattern of all zeros.
} else {
for (std::pair<CharUnits, CharUnits> Store : Stores) {
CharUnits StoreOffset = Store.first;
CharUnits StoreSize = Store.second;
llvm::Value *StoreSizeVal = CGF.CGM.getSize(StoreSize);
CGF.Builder.CreateMemSet(
CGF.Builder.CreateConstInBoundsByteGEP(DestPtr, StoreOffset),
CGF.Builder.getInt8(0), StoreSizeVal);
}
}
}
void
CodeGenFunction::EmitCXXConstructExpr(const CXXConstructExpr *E,
AggValueSlot Dest) {
assert(!Dest.isIgnored() && "Must have a destination!");
const CXXConstructorDecl *CD = E->getConstructor();
// If we require zero initialization before (or instead of) calling the
// constructor, as can be the case with a non-user-provided default
// constructor, emit the zero initialization now, unless destination is
// already zeroed.
if (E->requiresZeroInitialization() && !Dest.isZeroed()) {
switch (E->getConstructionKind()) {
case CXXConstructExpr::CK_Delegating:
case CXXConstructExpr::CK_Complete:
EmitNullInitialization(Dest.getAddress(), E->getType());
break;
case CXXConstructExpr::CK_VirtualBase:
case CXXConstructExpr::CK_NonVirtualBase:
EmitNullBaseClassInitialization(*this, Dest.getAddress(),
CD->getParent());
break;
}
}
// If this is a call to a trivial default constructor, do nothing.
if (CD->isTrivial() && CD->isDefaultConstructor())
return;
// Elide the constructor if we're constructing from a temporary.
// The temporary check is required because Sema sets this on NRVO
// returns.
if (getLangOpts().ElideConstructors && E->isElidable()) {
assert(getContext().hasSameUnqualifiedType(E->getType(),
E->getArg(0)->getType()));
if (E->getArg(0)->isTemporaryObject(getContext(), CD->getParent())) {
EmitAggExpr(E->getArg(0), Dest);
return;
}
}
if (const ArrayType *arrayType
= getContext().getAsArrayType(E->getType())) {
EmitCXXAggrConstructorCall(CD, arrayType, Dest.getAddress(), E);
} else {
CXXCtorType Type = Ctor_Complete;
bool ForVirtualBase = false;
bool Delegating = false;
switch (E->getConstructionKind()) {
case CXXConstructExpr::CK_Delegating:
// We should be emitting a constructor; GlobalDecl will assert this
Type = CurGD.getCtorType();
Delegating = true;
break;
case CXXConstructExpr::CK_Complete:
Type = Ctor_Complete;
break;
case CXXConstructExpr::CK_VirtualBase:
ForVirtualBase = true;
// fall-through
case CXXConstructExpr::CK_NonVirtualBase:
Type = Ctor_Base;
}
// Call the constructor.
EmitCXXConstructorCall(CD, Type, ForVirtualBase, Delegating,
Dest.getAddress(), E);
}
}
void CodeGenFunction::EmitSynthesizedCXXCopyCtor(Address Dest, Address Src,
const Expr *Exp) {
if (const ExprWithCleanups *E = dyn_cast<ExprWithCleanups>(Exp))
Exp = E->getSubExpr();
assert(isa<CXXConstructExpr>(Exp) &&
"EmitSynthesizedCXXCopyCtor - unknown copy ctor expr");
const CXXConstructExpr* E = cast<CXXConstructExpr>(Exp);
const CXXConstructorDecl *CD = E->getConstructor();
RunCleanupsScope Scope(*this);
// If we require zero initialization before (or instead of) calling the
// constructor, as can be the case with a non-user-provided default
// constructor, emit the zero initialization now.
// FIXME. Do I still need this for a copy ctor synthesis?
if (E->requiresZeroInitialization())
EmitNullInitialization(Dest, E->getType());
assert(!getContext().getAsConstantArrayType(E->getType())
&& "EmitSynthesizedCXXCopyCtor - Copied-in Array");
EmitSynthesizedCXXCopyCtorCall(CD, Dest, Src, E);
}
static CharUnits CalculateCookiePadding(CodeGenFunction &CGF,
const CXXNewExpr *E) {
if (!E->isArray())
return CharUnits::Zero();
// No cookie is required if the operator new[] being used is the
// reserved placement operator new[].
if (E->getOperatorNew()->isReservedGlobalPlacementOperator())
return CharUnits::Zero();
return CGF.CGM.getCXXABI().GetArrayCookieSize(E);
}
static llvm::Value *EmitCXXNewAllocSize(CodeGenFunction &CGF,
const CXXNewExpr *e,
unsigned minElements,
llvm::Value *&numElements,
llvm::Value *&sizeWithoutCookie) {
QualType type = e->getAllocatedType();
if (!e->isArray()) {
CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type);
sizeWithoutCookie
= llvm::ConstantInt::get(CGF.SizeTy, typeSize.getQuantity());
return sizeWithoutCookie;
}
// The width of size_t.
unsigned sizeWidth = CGF.SizeTy->getBitWidth();
// Figure out the cookie size.
llvm::APInt cookieSize(sizeWidth,
CalculateCookiePadding(CGF, e).getQuantity());
// Emit the array size expression.
// We multiply the size of all dimensions for NumElements.
// e.g for 'int[2][3]', ElemType is 'int' and NumElements is 6.
numElements = CGF.EmitScalarExpr(e->getArraySize());
assert(isa<llvm::IntegerType>(numElements->getType()));
// The number of elements can be have an arbitrary integer type;
// essentially, we need to multiply it by a constant factor, add a
// cookie size, and verify that the result is representable as a
// size_t. That's just a gloss, though, and it's wrong in one
// important way: if the count is negative, it's an error even if
// the cookie size would bring the total size >= 0.
bool isSigned
= e->getArraySize()->getType()->isSignedIntegerOrEnumerationType();
llvm::IntegerType *numElementsType
= cast<llvm::IntegerType>(numElements->getType());
unsigned numElementsWidth = numElementsType->getBitWidth();
// Compute the constant factor.
llvm::APInt arraySizeMultiplier(sizeWidth, 1);
while (const ConstantArrayType *CAT
= CGF.getContext().getAsConstantArrayType(type)) {
type = CAT->getElementType();
arraySizeMultiplier *= CAT->getSize();
}
CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type);
llvm::APInt typeSizeMultiplier(sizeWidth, typeSize.getQuantity());
typeSizeMultiplier *= arraySizeMultiplier;
// This will be a size_t.
llvm::Value *size;
// If someone is doing 'new int[42]' there is no need to do a dynamic check.
// Don't bloat the -O0 code.
if (llvm::ConstantInt *numElementsC =
dyn_cast<llvm::ConstantInt>(numElements)) {
const llvm::APInt &count = numElementsC->getValue();
bool hasAnyOverflow = false;
// If 'count' was a negative number, it's an overflow.
if (isSigned && count.isNegative())
hasAnyOverflow = true;
// We want to do all this arithmetic in size_t. If numElements is
// wider than that, check whether it's already too big, and if so,
// overflow.
else if (numElementsWidth > sizeWidth &&
numElementsWidth - sizeWidth > count.countLeadingZeros())
hasAnyOverflow = true;
// Okay, compute a count at the right width.
llvm::APInt adjustedCount = count.zextOrTrunc(sizeWidth);
// If there is a brace-initializer, we cannot allocate fewer elements than
// there are initializers. If we do, that's treated like an overflow.
if (adjustedCount.ult(minElements))
hasAnyOverflow = true;
// Scale numElements by that. This might overflow, but we don't
// care because it only overflows if allocationSize does, too, and
// if that overflows then we shouldn't use this.
numElements = llvm::ConstantInt::get(CGF.SizeTy,
adjustedCount * arraySizeMultiplier);
// Compute the size before cookie, and track whether it overflowed.
bool overflow;
llvm::APInt allocationSize
= adjustedCount.umul_ov(typeSizeMultiplier, overflow);
hasAnyOverflow |= overflow;
// Add in the cookie, and check whether it's overflowed.
if (cookieSize != 0) {
// Save the current size without a cookie. This shouldn't be
// used if there was overflow.
sizeWithoutCookie = llvm::ConstantInt::get(CGF.SizeTy, allocationSize);
allocationSize = allocationSize.uadd_ov(cookieSize, overflow);
hasAnyOverflow |= overflow;
}
// On overflow, produce a -1 so operator new will fail.
if (hasAnyOverflow) {
size = llvm::Constant::getAllOnesValue(CGF.SizeTy);
} else {
size = llvm::ConstantInt::get(CGF.SizeTy, allocationSize);
}
// Otherwise, we might need to use the overflow intrinsics.
} else {
// There are up to five conditions we need to test for:
// 1) if isSigned, we need to check whether numElements is negative;
// 2) if numElementsWidth > sizeWidth, we need to check whether
// numElements is larger than something representable in size_t;
// 3) if minElements > 0, we need to check whether numElements is smaller
// than that.
// 4) we need to compute
// sizeWithoutCookie := numElements * typeSizeMultiplier
// and check whether it overflows; and
// 5) if we need a cookie, we need to compute
// size := sizeWithoutCookie + cookieSize
// and check whether it overflows.
llvm::Value *hasOverflow = nullptr;
// If numElementsWidth > sizeWidth, then one way or another, we're
// going to have to do a comparison for (2), and this happens to
// take care of (1), too.
if (numElementsWidth > sizeWidth) {
llvm::APInt threshold(numElementsWidth, 1);
threshold <<= sizeWidth;
llvm::Value *thresholdV
= llvm::ConstantInt::get(numElementsType, threshold);
hasOverflow = CGF.Builder.CreateICmpUGE(numElements, thresholdV);
numElements = CGF.Builder.CreateTrunc(numElements, CGF.SizeTy);
// Otherwise, if we're signed, we want to sext up to size_t.
} else if (isSigned) {
if (numElementsWidth < sizeWidth)
numElements = CGF.Builder.CreateSExt(numElements, CGF.SizeTy);
// If there's a non-1 type size multiplier, then we can do the
// signedness check at the same time as we do the multiply
// because a negative number times anything will cause an
// unsigned overflow. Otherwise, we have to do it here. But at least
// in this case, we can subsume the >= minElements check.
if (typeSizeMultiplier == 1)
hasOverflow = CGF.Builder.CreateICmpSLT(numElements,
llvm::ConstantInt::get(CGF.SizeTy, minElements));
// Otherwise, zext up to size_t if necessary.
} else if (numElementsWidth < sizeWidth) {
numElements = CGF.Builder.CreateZExt(numElements, CGF.SizeTy);
}
assert(numElements->getType() == CGF.SizeTy);
if (minElements) {
// Don't allow allocation of fewer elements than we have initializers.
if (!hasOverflow) {
hasOverflow = CGF.Builder.CreateICmpULT(numElements,
llvm::ConstantInt::get(CGF.SizeTy, minElements));
} else if (numElementsWidth > sizeWidth) {
// The other existing overflow subsumes this check.
// We do an unsigned comparison, since any signed value < -1 is
// taken care of either above or below.
hasOverflow = CGF.Builder.CreateOr(hasOverflow,
CGF.Builder.CreateICmpULT(numElements,
llvm::ConstantInt::get(CGF.SizeTy, minElements)));
}
}
size = numElements;
// Multiply by the type size if necessary. This multiplier
// includes all the factors for nested arrays.
//
// This step also causes numElements to be scaled up by the
// nested-array factor if necessary. Overflow on this computation
// can be ignored because the result shouldn't be used if
// allocation fails.
if (typeSizeMultiplier != 1) {
llvm::Value *umul_with_overflow
= CGF.CGM.getIntrinsic(llvm::Intrinsic::umul_with_overflow, CGF.SizeTy);
llvm::Value *tsmV =
llvm::ConstantInt::get(CGF.SizeTy, typeSizeMultiplier);
llvm::Value *result =
CGF.Builder.CreateCall(umul_with_overflow, {size, tsmV});
llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1);
if (hasOverflow)
hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed);
else
hasOverflow = overflowed;
size = CGF.Builder.CreateExtractValue(result, 0);
// Also scale up numElements by the array size multiplier.
if (arraySizeMultiplier != 1) {
// If the base element type size is 1, then we can re-use the
// multiply we just did.
if (typeSize.isOne()) {
assert(arraySizeMultiplier == typeSizeMultiplier);
numElements = size;
// Otherwise we need a separate multiply.
} else {
llvm::Value *asmV =
llvm::ConstantInt::get(CGF.SizeTy, arraySizeMultiplier);
numElements = CGF.Builder.CreateMul(numElements, asmV);
}
}
} else {
// numElements doesn't need to be scaled.
assert(arraySizeMultiplier == 1);
}
// Add in the cookie size if necessary.
if (cookieSize != 0) {
sizeWithoutCookie = size;
llvm::Value *uadd_with_overflow
= CGF.CGM.getIntrinsic(llvm::Intrinsic::uadd_with_overflow, CGF.SizeTy);
llvm::Value *cookieSizeV = llvm::ConstantInt::get(CGF.SizeTy, cookieSize);
llvm::Value *result =
CGF.Builder.CreateCall(uadd_with_overflow, {size, cookieSizeV});
llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1);
if (hasOverflow)
hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed);
else
hasOverflow = overflowed;
size = CGF.Builder.CreateExtractValue(result, 0);
}
// If we had any possibility of dynamic overflow, make a select to
// overwrite 'size' with an all-ones value, which should cause
// operator new to throw.
if (hasOverflow)
size = CGF.Builder.CreateSelect(hasOverflow,
llvm::Constant::getAllOnesValue(CGF.SizeTy),
size);
}
if (cookieSize == 0)
sizeWithoutCookie = size;
else
assert(sizeWithoutCookie && "didn't set sizeWithoutCookie?");
return size;
}
static void StoreAnyExprIntoOneUnit(CodeGenFunction &CGF, const Expr *Init,
QualType AllocType, Address NewPtr) {
// FIXME: Refactor with EmitExprAsInit.
switch (CGF.getEvaluationKind(AllocType)) {
case TEK_Scalar:
CGF.EmitScalarInit(Init, nullptr,
CGF.MakeAddrLValue(NewPtr, AllocType), false);
return;
case TEK_Complex:
CGF.EmitComplexExprIntoLValue(Init, CGF.MakeAddrLValue(NewPtr, AllocType),
/*isInit*/ true);
return;
case TEK_Aggregate: {
AggValueSlot Slot
= AggValueSlot::forAddr(NewPtr, AllocType.getQualifiers(),
AggValueSlot::IsDestructed,
AggValueSlot::DoesNotNeedGCBarriers,
AggValueSlot::IsNotAliased);
CGF.EmitAggExpr(Init, Slot);
return;
}
}
llvm_unreachable("bad evaluation kind");
}
void CodeGenFunction::EmitNewArrayInitializer(
const CXXNewExpr *E, QualType ElementType, llvm::Type *ElementTy,
Address BeginPtr, llvm::Value *NumElements,
llvm::Value *AllocSizeWithoutCookie) {
// If we have a type with trivial initialization and no initializer,
// there's nothing to do.
if (!E->hasInitializer())
return;
Address CurPtr = BeginPtr;
unsigned InitListElements = 0;
const Expr *Init = E->getInitializer();
Address EndOfInit = Address::invalid();
QualType::DestructionKind DtorKind = ElementType.isDestructedType();
EHScopeStack::stable_iterator Cleanup;
llvm::Instruction *CleanupDominator = nullptr;
CharUnits ElementSize = getContext().getTypeSizeInChars(ElementType);
CharUnits ElementAlign =
BeginPtr.getAlignment().alignmentOfArrayElement(ElementSize);
// If the initializer is an initializer list, first do the explicit elements.
if (const InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
InitListElements = ILE->getNumInits();
// If this is a multi-dimensional array new, we will initialize multiple
// elements with each init list element.
QualType AllocType = E->getAllocatedType();
if (const ConstantArrayType *CAT = dyn_cast_or_null<ConstantArrayType>(
AllocType->getAsArrayTypeUnsafe())) {
ElementTy = ConvertTypeForMem(AllocType);
CurPtr = Builder.CreateElementBitCast(CurPtr, ElementTy);
InitListElements *= getContext().getConstantArrayElementCount(CAT);
}
// Enter a partial-destruction Cleanup if necessary.
if (needsEHCleanup(DtorKind)) {
// In principle we could tell the Cleanup where we are more
// directly, but the control flow can get so varied here that it
// would actually be quite complex. Therefore we go through an
// alloca.
EndOfInit = CreateTempAlloca(BeginPtr.getType(), getPointerAlign(),
"array.init.end");
CleanupDominator = Builder.CreateStore(BeginPtr.getPointer(), EndOfInit);
pushIrregularPartialArrayCleanup(BeginPtr.getPointer(), EndOfInit,
ElementType, ElementAlign,
getDestroyer(DtorKind));
Cleanup = EHStack.stable_begin();
}
CharUnits StartAlign = CurPtr.getAlignment();
for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i) {
// Tell the cleanup that it needs to destroy up to this
// element. TODO: some of these stores can be trivially
// observed to be unnecessary.
if (EndOfInit.isValid()) {
auto FinishedPtr =
Builder.CreateBitCast(CurPtr.getPointer(), BeginPtr.getType());
Builder.CreateStore(FinishedPtr, EndOfInit);
}
// FIXME: If the last initializer is an incomplete initializer list for
// an array, and we have an array filler, we can fold together the two
// initialization loops.
StoreAnyExprIntoOneUnit(*this, ILE->getInit(i),
ILE->getInit(i)->getType(), CurPtr);
CurPtr = Address(Builder.CreateInBoundsGEP(CurPtr.getPointer(),
Builder.getSize(1),
"array.exp.next"),
StartAlign.alignmentAtOffset((i + 1) * ElementSize));
}
// The remaining elements are filled with the array filler expression.
Init = ILE->getArrayFiller();
// Extract the initializer for the individual array elements by pulling
// out the array filler from all the nested initializer lists. This avoids
// generating a nested loop for the initialization.
while (Init && Init->getType()->isConstantArrayType()) {
auto *SubILE = dyn_cast<InitListExpr>(Init);
if (!SubILE)
break;
assert(SubILE->getNumInits() == 0 && "explicit inits in array filler?");
Init = SubILE->getArrayFiller();
}
// Switch back to initializing one base element at a time.
CurPtr = Builder.CreateBitCast(CurPtr, BeginPtr.getType());
}
// Attempt to perform zero-initialization using memset.
auto TryMemsetInitialization = [&]() -> bool {
// FIXME: If the type is a pointer-to-data-member under the Itanium ABI,
// we can initialize with a memset to -1.
if (!CGM.getTypes().isZeroInitializable(ElementType))
return false;
// Optimization: since zero initialization will just set the memory
// to all zeroes, generate a single memset to do it in one shot.
// Subtract out the size of any elements we've already initialized.
auto *RemainingSize = AllocSizeWithoutCookie;
if (InitListElements) {
// We know this can't overflow; we check this when doing the allocation.
auto *InitializedSize = llvm::ConstantInt::get(
RemainingSize->getType(),
getContext().getTypeSizeInChars(ElementType).getQuantity() *
InitListElements);
RemainingSize = Builder.CreateSub(RemainingSize, InitializedSize);
}
// Create the memset.
Builder.CreateMemSet(CurPtr, Builder.getInt8(0), RemainingSize, false);
return true;
};
// If all elements have already been initialized, skip any further
// initialization.
llvm::ConstantInt *ConstNum = dyn_cast<llvm::ConstantInt>(NumElements);
if (ConstNum && ConstNum->getZExtValue() <= InitListElements) {
// If there was a Cleanup, deactivate it.
if (CleanupDominator)
DeactivateCleanupBlock(Cleanup, CleanupDominator);
return;
}
assert(Init && "have trailing elements to initialize but no initializer");
// If this is a constructor call, try to optimize it out, and failing that
// emit a single loop to initialize all remaining elements.
if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(Init)) {
CXXConstructorDecl *Ctor = CCE->getConstructor();
if (Ctor->isTrivial()) {
// If new expression did not specify value-initialization, then there
// is no initialization.
if (!CCE->requiresZeroInitialization() || Ctor->getParent()->isEmpty())
return;
if (TryMemsetInitialization())
return;
}
// Store the new Cleanup position for irregular Cleanups.
//
// FIXME: Share this cleanup with the constructor call emission rather than
// having it create a cleanup of its own.
if (EndOfInit.isValid())
Builder.CreateStore(CurPtr.getPointer(), EndOfInit);
// Emit a constructor call loop to initialize the remaining elements.
if (InitListElements)
NumElements = Builder.CreateSub(
NumElements,
llvm::ConstantInt::get(NumElements->getType(), InitListElements));
EmitCXXAggrConstructorCall(Ctor, NumElements, CurPtr, CCE,
CCE->requiresZeroInitialization());
return;
}
// If this is value-initialization, we can usually use memset.
ImplicitValueInitExpr IVIE(ElementType);
if (isa<ImplicitValueInitExpr>(Init)) {
if (TryMemsetInitialization())
return;
// Switch to an ImplicitValueInitExpr for the element type. This handles
// only one case: multidimensional array new of pointers to members. In
// all other cases, we already have an initializer for the array element.
Init = &IVIE;
}
// At this point we should have found an initializer for the individual
// elements of the array.
assert(getContext().hasSameUnqualifiedType(ElementType, Init->getType()) &&
"got wrong type of element to initialize");
// If we have an empty initializer list, we can usually use memset.
if (auto *ILE = dyn_cast<InitListExpr>(Init))
if (ILE->getNumInits() == 0 && TryMemsetInitialization())
return;
// If we have a struct whose every field is value-initialized, we can
// usually use memset.
if (auto *ILE = dyn_cast<InitListExpr>(Init)) {
if (const RecordType *RType = ILE->getType()->getAs<RecordType>()) {
if (RType->getDecl()->isStruct()) {
unsigned NumElements = 0;
if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RType->getDecl()))
NumElements = CXXRD->getNumBases();
for (auto *Field : RType->getDecl()->fields())
if (!Field->isUnnamedBitfield())
++NumElements;
// FIXME: Recurse into nested InitListExprs.
if (ILE->getNumInits() == NumElements)
for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i)
if (!isa<ImplicitValueInitExpr>(ILE->getInit(i)))
--NumElements;
if (ILE->getNumInits() == NumElements && TryMemsetInitialization())
return;
}
}
}
// Create the loop blocks.
llvm::BasicBlock *EntryBB = Builder.GetInsertBlock();
llvm::BasicBlock *LoopBB = createBasicBlock("new.loop");
llvm::BasicBlock *ContBB = createBasicBlock("new.loop.end");
// Find the end of the array, hoisted out of the loop.
llvm::Value *EndPtr =
Builder.CreateInBoundsGEP(BeginPtr.getPointer(), NumElements, "array.end");
// If the number of elements isn't constant, we have to now check if there is
// anything left to initialize.
if (!ConstNum) {
llvm::Value *IsEmpty =
Builder.CreateICmpEQ(CurPtr.getPointer(), EndPtr, "array.isempty");
Builder.CreateCondBr(IsEmpty, ContBB, LoopBB);
}
// Enter the loop.
EmitBlock(LoopBB);
// Set up the current-element phi.
llvm::PHINode *CurPtrPhi =
Builder.CreatePHI(CurPtr.getType(), 2, "array.cur");
CurPtrPhi->addIncoming(CurPtr.getPointer(), EntryBB);
CurPtr = Address(CurPtrPhi, ElementAlign);
// Store the new Cleanup position for irregular Cleanups.
if (EndOfInit.isValid())
Builder.CreateStore(CurPtr.getPointer(), EndOfInit);
// Enter a partial-destruction Cleanup if necessary.
if (!CleanupDominator && needsEHCleanup(DtorKind)) {
pushRegularPartialArrayCleanup(BeginPtr.getPointer(), CurPtr.getPointer(),
ElementType, ElementAlign,
getDestroyer(DtorKind));
Cleanup = EHStack.stable_begin();
CleanupDominator = Builder.CreateUnreachable();
}
// Emit the initializer into this element.
StoreAnyExprIntoOneUnit(*this, Init, Init->getType(), CurPtr);
// Leave the Cleanup if we entered one.
if (CleanupDominator) {
DeactivateCleanupBlock(Cleanup, CleanupDominator);
CleanupDominator->eraseFromParent();
}
// Advance to the next element by adjusting the pointer type as necessary.
llvm::Value *NextPtr =
Builder.CreateConstInBoundsGEP1_32(ElementTy, CurPtr.getPointer(), 1,
"array.next");
// Check whether we've gotten to the end of the array and, if so,
// exit the loop.
llvm::Value *IsEnd = Builder.CreateICmpEQ(NextPtr, EndPtr, "array.atend");
Builder.CreateCondBr(IsEnd, ContBB, LoopBB);
CurPtrPhi->addIncoming(NextPtr, Builder.GetInsertBlock());
EmitBlock(ContBB);
}
static void EmitNewInitializer(CodeGenFunction &CGF, const CXXNewExpr *E,
QualType ElementType, llvm::Type *ElementTy,
Address NewPtr, llvm::Value *NumElements,
llvm::Value *AllocSizeWithoutCookie) {
ApplyDebugLocation DL(CGF, E);
if (E->isArray())
CGF.EmitNewArrayInitializer(E, ElementType, ElementTy, NewPtr, NumElements,
AllocSizeWithoutCookie);
else if (const Expr *Init = E->getInitializer())
StoreAnyExprIntoOneUnit(CGF, Init, E->getAllocatedType(), NewPtr);
}
/// Emit a call to an operator new or operator delete function, as implicitly
/// created by new-expressions and delete-expressions.
static RValue EmitNewDeleteCall(CodeGenFunction &CGF,
const FunctionDecl *Callee,
const FunctionProtoType *CalleeType,
const CallArgList &Args) {
llvm::Instruction *CallOrInvoke;
llvm::Value *CalleeAddr = CGF.CGM.GetAddrOfFunction(Callee);
RValue RV =
CGF.EmitCall(CGF.CGM.getTypes().arrangeFreeFunctionCall(
Args, CalleeType, /*chainCall=*/false),
CalleeAddr, ReturnValueSlot(), Args, Callee, &CallOrInvoke);
/// C++1y [expr.new]p10:
/// [In a new-expression,] an implementation is allowed to omit a call
/// to a replaceable global allocation function.
///
/// We model such elidable calls with the 'builtin' attribute.
llvm::Function *Fn = dyn_cast<llvm::Function>(CalleeAddr);
if (Callee->isReplaceableGlobalAllocationFunction() &&
Fn && Fn->hasFnAttribute(llvm::Attribute::NoBuiltin)) {
// FIXME: Add addAttribute to CallSite.
if (llvm::CallInst *CI = dyn_cast<llvm::CallInst>(CallOrInvoke))
CI->addAttribute(llvm::AttributeSet::FunctionIndex,
llvm::Attribute::Builtin);
else if (llvm::InvokeInst *II = dyn_cast<llvm::InvokeInst>(CallOrInvoke))
II->addAttribute(llvm::AttributeSet::FunctionIndex,
llvm::Attribute::Builtin);
else
llvm_unreachable("unexpected kind of call instruction");
}
return RV;
}
RValue CodeGenFunction::EmitBuiltinNewDeleteCall(const FunctionProtoType *Type,
const Expr *Arg,
bool IsDelete) {
CallArgList Args;
const Stmt *ArgS = Arg;
EmitCallArgs(Args, *Type->param_type_begin(), llvm::makeArrayRef(ArgS));
// Find the allocation or deallocation function that we're calling.
ASTContext &Ctx = getContext();
DeclarationName Name = Ctx.DeclarationNames
.getCXXOperatorName(IsDelete ? OO_Delete : OO_New);
for (auto *Decl : Ctx.getTranslationUnitDecl()->lookup(Name))
if (auto *FD = dyn_cast<FunctionDecl>(Decl))
if (Ctx.hasSameType(FD->getType(), QualType(Type, 0)))
return EmitNewDeleteCall(*this, cast<FunctionDecl>(Decl), Type, Args);
llvm_unreachable("predeclared global operator new/delete is missing");
}
namespace {
/// A cleanup to call the given 'operator delete' function upon
/// abnormal exit from a new expression.
class CallDeleteDuringNew final : public EHScopeStack::Cleanup {
size_t NumPlacementArgs;
const FunctionDecl *OperatorDelete;
llvm::Value *Ptr;
llvm::Value *AllocSize;
RValue *getPlacementArgs() { return reinterpret_cast<RValue*>(this+1); }
public:
static size_t getExtraSize(size_t NumPlacementArgs) {
return NumPlacementArgs * sizeof(RValue);
}
CallDeleteDuringNew(size_t NumPlacementArgs,
const FunctionDecl *OperatorDelete,
llvm::Value *Ptr,
llvm::Value *AllocSize)
: NumPlacementArgs(NumPlacementArgs), OperatorDelete(OperatorDelete),
Ptr(Ptr), AllocSize(AllocSize) {}
void setPlacementArg(unsigned I, RValue Arg) {
assert(I < NumPlacementArgs && "index out of range");
getPlacementArgs()[I] = Arg;
}
void Emit(CodeGenFunction &CGF, Flags flags) override {
const FunctionProtoType *FPT
= OperatorDelete->getType()->getAs<FunctionProtoType>();
assert(FPT->getNumParams() == NumPlacementArgs + 1 ||
(FPT->getNumParams() == 2 && NumPlacementArgs == 0));
CallArgList DeleteArgs;
// The first argument is always a void*.
FunctionProtoType::param_type_iterator AI = FPT->param_type_begin();
DeleteArgs.add(RValue::get(Ptr), *AI++);
// A member 'operator delete' can take an extra 'size_t' argument.
if (FPT->getNumParams() == NumPlacementArgs + 2)
DeleteArgs.add(RValue::get(AllocSize), *AI++);
// Pass the rest of the arguments, which must match exactly.
for (unsigned I = 0; I != NumPlacementArgs; ++I)
DeleteArgs.add(getPlacementArgs()[I], *AI++);
// Call 'operator delete'.
EmitNewDeleteCall(CGF, OperatorDelete, FPT, DeleteArgs);
}
};
/// A cleanup to call the given 'operator delete' function upon
/// abnormal exit from a new expression when the new expression is
/// conditional.
class CallDeleteDuringConditionalNew final : public EHScopeStack::Cleanup {
size_t NumPlacementArgs;
const FunctionDecl *OperatorDelete;
DominatingValue<RValue>::saved_type Ptr;
DominatingValue<RValue>::saved_type AllocSize;
DominatingValue<RValue>::saved_type *getPlacementArgs() {
return reinterpret_cast<DominatingValue<RValue>::saved_type*>(this+1);
}
public:
static size_t getExtraSize(size_t NumPlacementArgs) {
return NumPlacementArgs * sizeof(DominatingValue<RValue>::saved_type);
}
CallDeleteDuringConditionalNew(size_t NumPlacementArgs,
const FunctionDecl *OperatorDelete,
DominatingValue<RValue>::saved_type Ptr,
DominatingValue<RValue>::saved_type AllocSize)
: NumPlacementArgs(NumPlacementArgs), OperatorDelete(OperatorDelete),
Ptr(Ptr), AllocSize(AllocSize) {}
void setPlacementArg(unsigned I, DominatingValue<RValue>::saved_type Arg) {
assert(I < NumPlacementArgs && "index out of range");
getPlacementArgs()[I] = Arg;
}
void Emit(CodeGenFunction &CGF, Flags flags) override {
const FunctionProtoType *FPT
= OperatorDelete->getType()->getAs<FunctionProtoType>();
assert(FPT->getNumParams() == NumPlacementArgs + 1 ||
(FPT->getNumParams() == 2 && NumPlacementArgs == 0));
CallArgList DeleteArgs;
// The first argument is always a void*.
FunctionProtoType::param_type_iterator AI = FPT->param_type_begin();
DeleteArgs.add(Ptr.restore(CGF), *AI++);
// A member 'operator delete' can take an extra 'size_t' argument.
if (FPT->getNumParams() == NumPlacementArgs + 2) {
RValue RV = AllocSize.restore(CGF);
DeleteArgs.add(RV, *AI++);
}
// Pass the rest of the arguments, which must match exactly.
for (unsigned I = 0; I != NumPlacementArgs; ++I) {
RValue RV = getPlacementArgs()[I].restore(CGF);
DeleteArgs.add(RV, *AI++);
}
// Call 'operator delete'.
EmitNewDeleteCall(CGF, OperatorDelete, FPT, DeleteArgs);
}
};
}
/// Enter a cleanup to call 'operator delete' if the initializer in a
/// new-expression throws.
static void EnterNewDeleteCleanup(CodeGenFunction &CGF,
const CXXNewExpr *E,
Address NewPtr,
llvm::Value *AllocSize,
const CallArgList &NewArgs) {
// If we're not inside a conditional branch, then the cleanup will
// dominate and we can do the easier (and more efficient) thing.
if (!CGF.isInConditionalBranch()) {
CallDeleteDuringNew *Cleanup = CGF.EHStack
.pushCleanupWithExtra<CallDeleteDuringNew>(EHCleanup,
E->getNumPlacementArgs(),
E->getOperatorDelete(),
NewPtr.getPointer(),
AllocSize);
for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I)
Cleanup->setPlacementArg(I, NewArgs[I+1].RV);
return;
}
// Otherwise, we need to save all this stuff.
DominatingValue<RValue>::saved_type SavedNewPtr =
DominatingValue<RValue>::save(CGF, RValue::get(NewPtr.getPointer()));
DominatingValue<RValue>::saved_type SavedAllocSize =
DominatingValue<RValue>::save(CGF, RValue::get(AllocSize));
CallDeleteDuringConditionalNew *Cleanup = CGF.EHStack
.pushCleanupWithExtra<CallDeleteDuringConditionalNew>(EHCleanup,
E->getNumPlacementArgs(),
E->getOperatorDelete(),
SavedNewPtr,
SavedAllocSize);
for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I)
Cleanup->setPlacementArg(I,
DominatingValue<RValue>::save(CGF, NewArgs[I+1].RV));
CGF.initFullExprCleanup();
}
llvm::Value *CodeGenFunction::EmitCXXNewExpr(const CXXNewExpr *E) {
// The element type being allocated.
QualType allocType = getContext().getBaseElementType(E->getAllocatedType());
// 1. Build a call to the allocation function.
FunctionDecl *allocator = E->getOperatorNew();
// If there is a brace-initializer, cannot allocate fewer elements than inits.
unsigned minElements = 0;
if (E->isArray() && E->hasInitializer()) {
if (const InitListExpr *ILE = dyn_cast<InitListExpr>(E->getInitializer()))
minElements = ILE->getNumInits();
}
llvm::Value *numElements = nullptr;
llvm::Value *allocSizeWithoutCookie = nullptr;
llvm::Value *allocSize =
EmitCXXNewAllocSize(*this, E, minElements, numElements,
allocSizeWithoutCookie);
// Emit the allocation call. If the allocator is a global placement
// operator, just "inline" it directly.
Address allocation = Address::invalid();
CallArgList allocatorArgs;
if (allocator->isReservedGlobalPlacementOperator()) {
assert(E->getNumPlacementArgs() == 1);
const Expr *arg = *E->placement_arguments().begin();
AlignmentSource alignSource;
allocation = EmitPointerWithAlignment(arg, &alignSource);
// The pointer expression will, in many cases, be an opaque void*.
// In these cases, discard the computed alignment and use the
// formal alignment of the allocated type.
if (alignSource != AlignmentSource::Decl) {
allocation = Address(allocation.getPointer(),
getContext().getTypeAlignInChars(allocType));
}
// Set up allocatorArgs for the call to operator delete if it's not
// the reserved global operator.
if (E->getOperatorDelete() &&
!E->getOperatorDelete()->isReservedGlobalPlacementOperator()) {
allocatorArgs.add(RValue::get(allocSize), getContext().getSizeType());
allocatorArgs.add(RValue::get(allocation.getPointer()), arg->getType());
}
} else {
const FunctionProtoType *allocatorType =
allocator->getType()->castAs<FunctionProtoType>();
// The allocation size is the first argument.
QualType sizeType = getContext().getSizeType();
allocatorArgs.add(RValue::get(allocSize), sizeType);
// We start at 1 here because the first argument (the allocation size)
// has already been emitted.
EmitCallArgs(allocatorArgs, allocatorType, E->placement_arguments(),
/* CalleeDecl */ nullptr,
/*ParamsToSkip*/ 1);
RValue RV =
EmitNewDeleteCall(*this, allocator, allocatorType, allocatorArgs);
// For now, only assume that the allocation function returns
// something satisfactorily aligned for the element type, plus
// the cookie if we have one.
CharUnits allocationAlign =
getContext().getTypeAlignInChars(allocType);
if (allocSize != allocSizeWithoutCookie) {
CharUnits cookieAlign = getSizeAlign(); // FIXME?
allocationAlign = std::max(allocationAlign, cookieAlign);
}
allocation = Address(RV.getScalarVal(), allocationAlign);
}
// Emit a null check on the allocation result if the allocation
// function is allowed to return null (because it has a non-throwing
// exception spec or is the reserved placement new) and we have an
// interesting initializer.
bool nullCheck = E->shouldNullCheckAllocation(getContext()) &&
(!allocType.isPODType(getContext()) || E->hasInitializer());
llvm::BasicBlock *nullCheckBB = nullptr;
llvm::BasicBlock *contBB = nullptr;
// The null-check means that the initializer is conditionally
// evaluated.
ConditionalEvaluation conditional(*this);
if (nullCheck) {
conditional.begin(*this);
nullCheckBB = Builder.GetInsertBlock();
llvm::BasicBlock *notNullBB = createBasicBlock("new.notnull");
contBB = createBasicBlock("new.cont");
llvm::Value *isNull =
Builder.CreateIsNull(allocation.getPointer(), "new.isnull");
Builder.CreateCondBr(isNull, contBB, notNullBB);
EmitBlock(notNullBB);
}
// If there's an operator delete, enter a cleanup to call it if an
// exception is thrown.
EHScopeStack::stable_iterator operatorDeleteCleanup;
llvm::Instruction *cleanupDominator = nullptr;
if (E->getOperatorDelete() &&
!E->getOperatorDelete()->isReservedGlobalPlacementOperator()) {
EnterNewDeleteCleanup(*this, E, allocation, allocSize, allocatorArgs);
operatorDeleteCleanup = EHStack.stable_begin();
cleanupDominator = Builder.CreateUnreachable();
}
assert((allocSize == allocSizeWithoutCookie) ==
CalculateCookiePadding(*this, E).isZero());
if (allocSize != allocSizeWithoutCookie) {
assert(E->isArray());
allocation = CGM.getCXXABI().InitializeArrayCookie(*this, allocation,
numElements,
E, allocType);
}
llvm::Type *elementTy = ConvertTypeForMem(allocType);
Address result = Builder.CreateElementBitCast(allocation, elementTy);
// Passing pointer through invariant.group.barrier to avoid propagation of
// vptrs information which may be included in previous type.
if (CGM.getCodeGenOpts().StrictVTablePointers &&
CGM.getCodeGenOpts().OptimizationLevel > 0 &&
allocator->isReservedGlobalPlacementOperator())
result = Address(Builder.CreateInvariantGroupBarrier(result.getPointer()),
result.getAlignment());
EmitNewInitializer(*this, E, allocType, elementTy, result, numElements,
allocSizeWithoutCookie);
if (E->isArray()) {
// NewPtr is a pointer to the base element type. If we're
// allocating an array of arrays, we'll need to cast back to the
// array pointer type.
llvm::Type *resultType = ConvertTypeForMem(E->getType());
if (result.getType() != resultType)
result = Builder.CreateBitCast(result, resultType);
}
// Deactivate the 'operator delete' cleanup if we finished
// initialization.
if (operatorDeleteCleanup.isValid()) {
DeactivateCleanupBlock(operatorDeleteCleanup, cleanupDominator);
cleanupDominator->eraseFromParent();
}
llvm::Value *resultPtr = result.getPointer();
if (nullCheck) {
conditional.end(*this);
llvm::BasicBlock *notNullBB = Builder.GetInsertBlock();
EmitBlock(contBB);
llvm::PHINode *PHI = Builder.CreatePHI(resultPtr->getType(), 2);
PHI->addIncoming(resultPtr, notNullBB);
PHI->addIncoming(llvm::Constant::getNullValue(resultPtr->getType()),
nullCheckBB);
resultPtr = PHI;
}
return resultPtr;
}
void CodeGenFunction::EmitDeleteCall(const FunctionDecl *DeleteFD,
llvm::Value *Ptr,
QualType DeleteTy) {
assert(DeleteFD->getOverloadedOperator() == OO_Delete);
const FunctionProtoType *DeleteFTy =
DeleteFD->getType()->getAs<FunctionProtoType>();
CallArgList DeleteArgs;
// Check if we need to pass the size to the delete operator.
llvm::Value *Size = nullptr;
QualType SizeTy;
if (DeleteFTy->getNumParams() == 2) {
SizeTy = DeleteFTy->getParamType(1);
CharUnits DeleteTypeSize = getContext().getTypeSizeInChars(DeleteTy);
Size = llvm::ConstantInt::get(ConvertType(SizeTy),
DeleteTypeSize.getQuantity());
}
QualType ArgTy = DeleteFTy->getParamType(0);
llvm::Value *DeletePtr = Builder.CreateBitCast(Ptr, ConvertType(ArgTy));
DeleteArgs.add(RValue::get(DeletePtr), ArgTy);
if (Size)
DeleteArgs.add(RValue::get(Size), SizeTy);
// Emit the call to delete.
EmitNewDeleteCall(*this, DeleteFD, DeleteFTy, DeleteArgs);
}
namespace {
/// Calls the given 'operator delete' on a single object.
struct CallObjectDelete final : EHScopeStack::Cleanup {
llvm::Value *Ptr;
const FunctionDecl *OperatorDelete;
QualType ElementType;
CallObjectDelete(llvm::Value *Ptr,
const FunctionDecl *OperatorDelete,
QualType ElementType)
: Ptr(Ptr), OperatorDelete(OperatorDelete), ElementType(ElementType) {}
void Emit(CodeGenFunction &CGF, Flags flags) override {
CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType);
}
};
}
void
CodeGenFunction::pushCallObjectDeleteCleanup(const FunctionDecl *OperatorDelete,
llvm::Value *CompletePtr,
QualType ElementType) {
EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup, CompletePtr,
OperatorDelete, ElementType);
}
/// Emit the code for deleting a single object.
static void EmitObjectDelete(CodeGenFunction &CGF,
const CXXDeleteExpr *DE,
Address Ptr,
QualType ElementType) {
// Find the destructor for the type, if applicable. If the
// destructor is virtual, we'll just emit the vcall and return.
const CXXDestructorDecl *Dtor = nullptr;
if (const RecordType *RT = ElementType->getAs<RecordType>()) {
CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
if (RD->hasDefinition() && !RD->hasTrivialDestructor()) {
Dtor = RD->getDestructor();
if (Dtor->isVirtual()) {
CGF.CGM.getCXXABI().emitVirtualObjectDelete(CGF, DE, Ptr, ElementType,
Dtor);
return;
}
}
}
// Make sure that we call delete even if the dtor throws.
// This doesn't have to a conditional cleanup because we're going
// to pop it off in a second.
const FunctionDecl *OperatorDelete = DE->getOperatorDelete();
CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup,
Ptr.getPointer(),
OperatorDelete, ElementType);
if (Dtor)
CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
/*ForVirtualBase=*/false,
/*Delegating=*/false,
Ptr);
else if (auto Lifetime = ElementType.getObjCLifetime()) {
switch (Lifetime) {
case Qualifiers::OCL_None:
case Qualifiers::OCL_ExplicitNone:
case Qualifiers::OCL_Autoreleasing:
break;
case Qualifiers::OCL_Strong:
CGF.EmitARCDestroyStrong(Ptr, ARCPreciseLifetime);
break;
case Qualifiers::OCL_Weak:
CGF.EmitARCDestroyWeak(Ptr);
break;
}
}
CGF.PopCleanupBlock();
}
namespace {
/// Calls the given 'operator delete' on an array of objects.
struct CallArrayDelete final : EHScopeStack::Cleanup {
llvm::Value *Ptr;
const FunctionDecl *OperatorDelete;
llvm::Value *NumElements;
QualType ElementType;
CharUnits CookieSize;
CallArrayDelete(llvm::Value *Ptr,
const FunctionDecl *OperatorDelete,
llvm::Value *NumElements,
QualType ElementType,
CharUnits CookieSize)
: Ptr(Ptr), OperatorDelete(OperatorDelete), NumElements(NumElements),
ElementType(ElementType), CookieSize(CookieSize) {}
void Emit(CodeGenFunction &CGF, Flags flags) override {
const FunctionProtoType *DeleteFTy =
OperatorDelete->getType()->getAs<FunctionProtoType>();
assert(DeleteFTy->getNumParams() == 1 || DeleteFTy->getNumParams() == 2);
CallArgList Args;
// Pass the pointer as the first argument.
QualType VoidPtrTy = DeleteFTy->getParamType(0);
llvm::Value *DeletePtr
= CGF.Builder.CreateBitCast(Ptr, CGF.ConvertType(VoidPtrTy));
Args.add(RValue::get(DeletePtr), VoidPtrTy);
// Pass the original requested size as the second argument.
if (DeleteFTy->getNumParams() == 2) {
QualType size_t = DeleteFTy->getParamType(1);
llvm::IntegerType *SizeTy
= cast<llvm::IntegerType>(CGF.ConvertType(size_t));
CharUnits ElementTypeSize =
CGF.CGM.getContext().getTypeSizeInChars(ElementType);
// The size of an element, multiplied by the number of elements.
llvm::Value *Size
= llvm::ConstantInt::get(SizeTy, ElementTypeSize.getQuantity());
if (NumElements)
Size = CGF.Builder.CreateMul(Size, NumElements);
// Plus the size of the cookie if applicable.
if (!CookieSize.isZero()) {
llvm::Value *CookieSizeV
= llvm::ConstantInt::get(SizeTy, CookieSize.getQuantity());
Size = CGF.Builder.CreateAdd(Size, CookieSizeV);
}
Args.add(RValue::get(Size), size_t);
}
// Emit the call to delete.
EmitNewDeleteCall(CGF, OperatorDelete, DeleteFTy, Args);
}
};
}
/// Emit the code for deleting an array of objects.
static void EmitArrayDelete(CodeGenFunction &CGF,
const CXXDeleteExpr *E,
Address deletedPtr,
QualType elementType) {
llvm::Value *numElements = nullptr;
llvm::Value *allocatedPtr = nullptr;
CharUnits cookieSize;
CGF.CGM.getCXXABI().ReadArrayCookie(CGF, deletedPtr, E, elementType,
numElements, allocatedPtr, cookieSize);
assert(allocatedPtr && "ReadArrayCookie didn't set allocated pointer");
// Make sure that we call delete even if one of the dtors throws.
const FunctionDecl *operatorDelete = E->getOperatorDelete();
CGF.EHStack.pushCleanup<CallArrayDelete>(NormalAndEHCleanup,
allocatedPtr, operatorDelete,
numElements, elementType,
cookieSize);
// Destroy the elements.
if (QualType::DestructionKind dtorKind = elementType.isDestructedType()) {
assert(numElements && "no element count for a type with a destructor!");
CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType);
CharUnits elementAlign =
deletedPtr.getAlignment().alignmentOfArrayElement(elementSize);
llvm::Value *arrayBegin = deletedPtr.getPointer();
llvm::Value *arrayEnd =
CGF.Builder.CreateInBoundsGEP(arrayBegin, numElements, "delete.end");
// Note that it is legal to allocate a zero-length array, and we
// can never fold the check away because the length should always
// come from a cookie.
CGF.emitArrayDestroy(arrayBegin, arrayEnd, elementType, elementAlign,
CGF.getDestroyer(dtorKind),
/*checkZeroLength*/ true,
CGF.needsEHCleanup(dtorKind));
}
// Pop the cleanup block.
CGF.PopCleanupBlock();
}
void CodeGenFunction::EmitCXXDeleteExpr(const CXXDeleteExpr *E) {
const Expr *Arg = E->getArgument();
Address Ptr = EmitPointerWithAlignment(Arg);
// Null check the pointer.
llvm::BasicBlock *DeleteNotNull = createBasicBlock("delete.notnull");
llvm::BasicBlock *DeleteEnd = createBasicBlock("delete.end");
llvm::Value *IsNull = Builder.CreateIsNull(Ptr.getPointer(), "isnull");
Builder.CreateCondBr(IsNull, DeleteEnd, DeleteNotNull);
EmitBlock(DeleteNotNull);
// We might be deleting a pointer to array. If so, GEP down to the
// first non-array element.
// (this assumes that A(*)[3][7] is converted to [3 x [7 x %A]]*)
QualType DeleteTy = Arg->getType()->getAs<PointerType>()->getPointeeType();
if (DeleteTy->isConstantArrayType()) {
llvm::Value *Zero = Builder.getInt32(0);
SmallVector<llvm::Value*,8> GEP;
GEP.push_back(Zero); // point at the outermost array
// For each layer of array type we're pointing at:
while (const ConstantArrayType *Arr
= getContext().getAsConstantArrayType(DeleteTy)) {
// 1. Unpeel the array type.
DeleteTy = Arr->getElementType();
// 2. GEP to the first element of the array.
GEP.push_back(Zero);
}
Ptr = Address(Builder.CreateInBoundsGEP(Ptr.getPointer(), GEP, "del.first"),
Ptr.getAlignment());
}
assert(ConvertTypeForMem(DeleteTy) == Ptr.getElementType());
if (E->isArrayForm()) {
EmitArrayDelete(*this, E, Ptr, DeleteTy);
} else {
EmitObjectDelete(*this, E, Ptr, DeleteTy);
}
EmitBlock(DeleteEnd);
}
static bool isGLValueFromPointerDeref(const Expr *E) {
E = E->IgnoreParens();
if (const auto *CE = dyn_cast<CastExpr>(E)) {
if (!CE->getSubExpr()->isGLValue())
return false;
return isGLValueFromPointerDeref(CE->getSubExpr());
}
if (const auto *OVE = dyn_cast<OpaqueValueExpr>(E))
return isGLValueFromPointerDeref(OVE->getSourceExpr());
if (const auto *BO = dyn_cast<BinaryOperator>(E))
if (BO->getOpcode() == BO_Comma)
return isGLValueFromPointerDeref(BO->getRHS());
if (const auto *ACO = dyn_cast<AbstractConditionalOperator>(E))
return isGLValueFromPointerDeref(ACO->getTrueExpr()) ||
isGLValueFromPointerDeref(ACO->getFalseExpr());
// C++11 [expr.sub]p1:
// The expression E1[E2] is identical (by definition) to *((E1)+(E2))
if (isa<ArraySubscriptExpr>(E))
return true;
if (const auto *UO = dyn_cast<UnaryOperator>(E))
if (UO->getOpcode() == UO_Deref)
return true;
return false;
}
static llvm::Value *EmitTypeidFromVTable(CodeGenFunction &CGF, const Expr *E,
llvm::Type *StdTypeInfoPtrTy) {
// Get the vtable pointer.
Address ThisPtr = CGF.EmitLValue(E).getAddress();
// C++ [expr.typeid]p2:
// If the glvalue expression is obtained by applying the unary * operator to
// a pointer and the pointer is a null pointer value, the typeid expression
// throws the std::bad_typeid exception.
//
// However, this paragraph's intent is not clear. We choose a very generous
// interpretation which implores us to consider comma operators, conditional
// operators, parentheses and other such constructs.
QualType SrcRecordTy = E->getType();
if (CGF.CGM.getCXXABI().shouldTypeidBeNullChecked(
isGLValueFromPointerDeref(E), SrcRecordTy)) {
llvm::BasicBlock *BadTypeidBlock =
CGF.createBasicBlock("typeid.bad_typeid");
llvm::BasicBlock *EndBlock = CGF.createBasicBlock("typeid.end");
llvm::Value *IsNull = CGF.Builder.CreateIsNull(ThisPtr.getPointer());
CGF.Builder.CreateCondBr(IsNull, BadTypeidBlock, EndBlock);
CGF.EmitBlock(BadTypeidBlock);
CGF.CGM.getCXXABI().EmitBadTypeidCall(CGF);
CGF.EmitBlock(EndBlock);
}
return CGF.CGM.getCXXABI().EmitTypeid(CGF, SrcRecordTy, ThisPtr,
StdTypeInfoPtrTy);
}
llvm::Value *CodeGenFunction::EmitCXXTypeidExpr(const CXXTypeidExpr *E) {
llvm::Type *StdTypeInfoPtrTy =
ConvertType(E->getType())->getPointerTo();
if (E->isTypeOperand()) {
llvm::Constant *TypeInfo =
CGM.GetAddrOfRTTIDescriptor(E->getTypeOperand(getContext()));
return Builder.CreateBitCast(TypeInfo, StdTypeInfoPtrTy);
}
// C++ [expr.typeid]p2:
// When typeid is applied to a glvalue expression whose type is a
// polymorphic class type, the result refers to a std::type_info object
// representing the type of the most derived object (that is, the dynamic
// type) to which the glvalue refers.
if (E->isPotentiallyEvaluated())
return EmitTypeidFromVTable(*this, E->getExprOperand(),
StdTypeInfoPtrTy);
QualType OperandTy = E->getExprOperand()->getType();
return Builder.CreateBitCast(CGM.GetAddrOfRTTIDescriptor(OperandTy),
StdTypeInfoPtrTy);
}
static llvm::Value *EmitDynamicCastToNull(CodeGenFunction &CGF,
QualType DestTy) {
llvm::Type *DestLTy = CGF.ConvertType(DestTy);
if (DestTy->isPointerType())
return llvm::Constant::getNullValue(DestLTy);
/// C++ [expr.dynamic.cast]p9:
/// A failed cast to reference type throws std::bad_cast
if (!CGF.CGM.getCXXABI().EmitBadCastCall(CGF))
return nullptr;
CGF.EmitBlock(CGF.createBasicBlock("dynamic_cast.end"));
return llvm::UndefValue::get(DestLTy);
}
llvm::Value *CodeGenFunction::EmitDynamicCast(Address ThisAddr,
const CXXDynamicCastExpr *DCE) {
CGM.EmitExplicitCastExprType(DCE, this);
QualType DestTy = DCE->getTypeAsWritten();
if (DCE->isAlwaysNull())
if (llvm::Value *T = EmitDynamicCastToNull(*this, DestTy))
return T;
QualType SrcTy = DCE->getSubExpr()->getType();
// C++ [expr.dynamic.cast]p7:
// If T is "pointer to cv void," then the result is a pointer to the most
// derived object pointed to by v.
const PointerType *DestPTy = DestTy->getAs<PointerType>();
bool isDynamicCastToVoid;
QualType SrcRecordTy;
QualType DestRecordTy;
if (DestPTy) {
isDynamicCastToVoid = DestPTy->getPointeeType()->isVoidType();
SrcRecordTy = SrcTy->castAs<PointerType>()->getPointeeType();
DestRecordTy = DestPTy->getPointeeType();
} else {
isDynamicCastToVoid = false;
SrcRecordTy = SrcTy;
DestRecordTy = DestTy->castAs<ReferenceType>()->getPointeeType();
}
assert(SrcRecordTy->isRecordType() && "source type must be a record type!");
// C++ [expr.dynamic.cast]p4:
// If the value of v is a null pointer value in the pointer case, the result
// is the null pointer value of type T.
bool ShouldNullCheckSrcValue =
CGM.getCXXABI().shouldDynamicCastCallBeNullChecked(SrcTy->isPointerType(),
SrcRecordTy);
llvm::BasicBlock *CastNull = nullptr;
llvm::BasicBlock *CastNotNull = nullptr;
llvm::BasicBlock *CastEnd = createBasicBlock("dynamic_cast.end");
if (ShouldNullCheckSrcValue) {
CastNull = createBasicBlock("dynamic_cast.null");
CastNotNull = createBasicBlock("dynamic_cast.notnull");
llvm::Value *IsNull = Builder.CreateIsNull(ThisAddr.getPointer());
Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
EmitBlock(CastNotNull);
}
llvm::Value *Value;
if (isDynamicCastToVoid) {
Value = CGM.getCXXABI().EmitDynamicCastToVoid(*this, ThisAddr, SrcRecordTy,
DestTy);
} else {
assert(DestRecordTy->isRecordType() &&
"destination type must be a record type!");
Value = CGM.getCXXABI().EmitDynamicCastCall(*this, ThisAddr, SrcRecordTy,
DestTy, DestRecordTy, CastEnd);
CastNotNull = Builder.GetInsertBlock();
}
if (ShouldNullCheckSrcValue) {
EmitBranch(CastEnd);
EmitBlock(CastNull);
EmitBranch(CastEnd);
}
EmitBlock(CastEnd);
if (ShouldNullCheckSrcValue) {
llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2);
PHI->addIncoming(Value, CastNotNull);
PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()), CastNull);
Value = PHI;
}
return Value;
}
void CodeGenFunction::EmitLambdaExpr(const LambdaExpr *E, AggValueSlot Slot) {
RunCleanupsScope Scope(*this);
LValue SlotLV = MakeAddrLValue(Slot.getAddress(), E->getType());
CXXRecordDecl::field_iterator CurField = E->getLambdaClass()->field_begin();
for (LambdaExpr::const_capture_init_iterator i = E->capture_init_begin(),
e = E->capture_init_end();
i != e; ++i, ++CurField) {
// Emit initialization
LValue LV = EmitLValueForFieldInitialization(SlotLV, *CurField);
if (CurField->hasCapturedVLAType()) {
auto VAT = CurField->getCapturedVLAType();
EmitStoreThroughLValue(RValue::get(VLASizeMap[VAT->getSizeExpr()]), LV);
} else {
ArrayRef<VarDecl *> ArrayIndexes;
if (CurField->getType()->isArrayType())
ArrayIndexes = E->getCaptureInitIndexVars(i);
EmitInitializerForField(*CurField, LV, *i, ArrayIndexes);
}
}
}