maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity
llvm-project/clang/lib/CodeGen/CGExprCXX.cpp

1774 lines
65 KiB
C++
Raw Blame History

//===--- 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 "clang/Frontend/CodeGenOptions.h"
#include "CodeGenFunction.h"
#include "CGCUDARuntime.h"
#include "CGCXXABI.h"
#include "CGObjCRuntime.h"
#include "CGDebugInfo.h"
#include "llvm/Intrinsics.h"
#include "llvm/Support/CallSite.h"
using namespace clang;
using namespace CodeGen;
RValue CodeGenFunction::EmitCXXMemberCall(const CXXMethodDecl *MD,
llvm::Value *Callee,
ReturnValueSlot ReturnValue,
llvm::Value *This,
llvm::Value *VTT,
CallExpr::const_arg_iterator ArgBeg,
CallExpr::const_arg_iterator ArgEnd) {
assert(MD->isInstance() &&
"Trying to emit a member call expr on a static method!");
const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
CallArgList Args;
// Push the this ptr.
Args.add(RValue::get(This), MD->getThisType(getContext()));
// If there is a VTT parameter, emit it.
if (VTT) {
QualType T = getContext().getPointerType(getContext().VoidPtrTy);
Args.add(RValue::get(VTT), T);
}
// And the rest of the call args
EmitCallArgs(Args, FPT, ArgBeg, ArgEnd);
QualType ResultType = FPT->getResultType();
return EmitCall(CGM.getTypes().getFunctionInfo(ResultType, Args,
FPT->getExtInfo()),
Callee, ReturnValue, Args, MD);
}
static const CXXRecordDecl *getMostDerivedClassDecl(const Expr *Base) {
const Expr *E = Base;
while (true) {
E = E->IgnoreParens();
if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
if (CE->getCastKind() == CK_DerivedToBase ||
CE->getCastKind() == CK_UncheckedDerivedToBase ||
CE->getCastKind() == CK_NoOp) {
E = CE->getSubExpr();
continue;
}
}
break;
}
QualType DerivedType = E->getType();
if (const PointerType *PTy = DerivedType->getAs<PointerType>())
DerivedType = PTy->getPointeeType();
return cast<CXXRecordDecl>(DerivedType->castAs<RecordType>()->getDecl());
}
// FIXME: Ideally Expr::IgnoreParenNoopCasts should do this, but it doesn't do
// quite what we want.
static const Expr *skipNoOpCastsAndParens(const Expr *E) {
while (true) {
if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
E = PE->getSubExpr();
continue;
}
if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
if (CE->getCastKind() == CK_NoOp) {
E = CE->getSubExpr();
continue;
}
}
if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
if (UO->getOpcode() == UO_Extension) {
E = UO->getSubExpr();
continue;
}
}
return E;
}
}
/// canDevirtualizeMemberFunctionCalls - Checks whether virtual calls on given
/// expr can be devirtualized.
static bool canDevirtualizeMemberFunctionCalls(ASTContext &Context,
const Expr *Base,
const CXXMethodDecl *MD) {
// When building with -fapple-kext, all calls must go through the vtable since
// the kernel linker can do runtime patching of vtables.
if (Context.getLangOptions().AppleKext)
return false;
// If the most derived class is marked final, we know that no subclass can
// override this member function and so we can devirtualize it. For example:
//
// struct A { virtual void f(); }
// struct B final : A { };
//
// void f(B *b) {
// b->f();
// }
//
const CXXRecordDecl *MostDerivedClassDecl = getMostDerivedClassDecl(Base);
if (MostDerivedClassDecl->hasAttr<FinalAttr>())
return true;
// If the member function is marked 'final', we know that it can't be
// overridden and can therefore devirtualize it.
if (MD->hasAttr<FinalAttr>())
return true;
// Similarly, if the class itself is marked 'final' it can't be overridden
// and we can therefore devirtualize the member function call.
if (MD->getParent()->hasAttr<FinalAttr>())
return true;
Base = skipNoOpCastsAndParens(Base);
if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Base)) {
if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) {
// This is a record decl. We know the type and can devirtualize it.
return VD->getType()->isRecordType();
}
return false;
}
// We can always devirtualize calls on temporary object expressions.
if (isa<CXXConstructExpr>(Base))
return true;
// And calls on bound temporaries.
if (isa<CXXBindTemporaryExpr>(Base))
return true;
// Check if this is a call expr that returns a record type.
if (const CallExpr *CE = dyn_cast<CallExpr>(Base))
return CE->getCallReturnType()->isRecordType();
// We can't devirtualize the call.
return false;
}
// 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());
CGDebugInfo *DI = getDebugInfo();
if (DI && CGM.getCodeGenOpts().LimitDebugInfo
&& !isa<CallExpr>(ME->getBase())) {
QualType PQTy = ME->getBase()->IgnoreParenImpCasts()->getType();
if (const PointerType * PTy = dyn_cast<PointerType>(PQTy)) {
DI->getOrCreateRecordType(PTy->getPointeeType(),
MD->getParent()->getLocation());
}
}
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,
ReturnValue, CE->arg_begin(), CE->arg_end());
}
// Compute the object pointer.
llvm::Value *This;
if (ME->isArrow())
This = EmitScalarExpr(ME->getBase());
else
This = EmitLValue(ME->getBase()).getAddress();
if (MD->isTrivial()) {
if (isa<CXXDestructorDecl>(MD)) return RValue::get(0);
if (isa<CXXConstructorDecl>(MD) &&
cast<CXXConstructorDecl>(MD)->isDefaultConstructor())
return RValue::get(0);
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.
llvm::Value *RHS = EmitLValue(*CE->arg_begin()).getAddress();
EmitAggregateCopy(This, RHS, CE->getType());
return RValue::get(This);
}
if (isa<CXXConstructorDecl>(MD) &&
cast<CXXConstructorDecl>(MD)->isCopyOrMoveConstructor()) {
// Trivial move and copy ctor are the same.
llvm::Value *RHS = EmitLValue(*CE->arg_begin()).getAddress();
EmitSynthesizedCXXCopyCtorCall(cast<CXXConstructorDecl>(MD), This, RHS,
CE->arg_begin(), CE->arg_end());
return RValue::get(This);
}
llvm_unreachable("unknown trivial member function");
}
// Compute the function type we're calling.
const CGFunctionInfo *FInfo = 0;
if (isa<CXXDestructorDecl>(MD))
FInfo = &CGM.getTypes().getFunctionInfo(cast<CXXDestructorDecl>(MD),
Dtor_Complete);
else if (isa<CXXConstructorDecl>(MD))
FInfo = &CGM.getTypes().getFunctionInfo(cast<CXXConstructorDecl>(MD),
Ctor_Complete);
else
FInfo = &CGM.getTypes().getFunctionInfo(MD);
const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
llvm::Type *Ty
= CGM.getTypes().GetFunctionType(*FInfo, FPT->isVariadic());
// 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;
UseVirtualCall = MD->isVirtual() && !ME->hasQualifier()
&& !canDevirtualizeMemberFunctionCalls(getContext(),
ME->getBase(), MD);
llvm::Value *Callee;
if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(MD)) {
if (UseVirtualCall) {
Callee = BuildVirtualCall(Dtor, Dtor_Complete, This, Ty);
} else {
if (getContext().getLangOptions().AppleKext &&
MD->isVirtual() &&
ME->hasQualifier())
Callee = BuildAppleKextVirtualCall(MD, ME->getQualifier(), Ty);
else
Callee = CGM.GetAddrOfFunction(GlobalDecl(Dtor, Dtor_Complete), Ty);
}
} else if (const CXXConstructorDecl *Ctor =
dyn_cast<CXXConstructorDecl>(MD)) {
Callee = CGM.GetAddrOfFunction(GlobalDecl(Ctor, Ctor_Complete), Ty);
} else if (UseVirtualCall) {
Callee = BuildVirtualCall(MD, This, Ty);
} else {
if (getContext().getLangOptions().AppleKext &&
MD->isVirtual() &&
ME->hasQualifier())
Callee = BuildAppleKextVirtualCall(MD, ME->getQualifier(), Ty);
else
Callee = CGM.GetAddrOfFunction(MD, Ty);
}
return EmitCXXMemberCall(MD, Callee, ReturnValue, This, /*VTT=*/0,
CE->arg_begin(), CE->arg_end());
}
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.
llvm::Value *This;
if (BO->getOpcode() == BO_PtrMemI)
This = EmitScalarExpr(BaseExpr);
else
This = EmitLValue(BaseExpr).getAddress();
// Ask the ABI to load the callee. Note that This is modified.
llvm::Value *Callee =
CGM.getCXXABI().EmitLoadOfMemberFunctionPointer(*this, This, MemFnPtr, MPT);
CallArgList Args;
QualType ThisType =
getContext().getPointerType(getContext().getTagDeclType(RD));
// Push the this ptr.
Args.add(RValue::get(This), ThisType);
// And the rest of the call args
EmitCallArgs(Args, FPT, E->arg_begin(), E->arg_end());
return EmitCall(CGM.getTypes().getFunctionInfo(Args, FPT), 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!");
LValue LV = EmitLValue(E->getArg(0));
llvm::Value *This = LV.getAddress();
if ((MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) &&
MD->isTrivial()) {
llvm::Value *Src = EmitLValue(E->getArg(1)).getAddress();
QualType Ty = E->getType();
EmitAggregateCopy(This, Src, Ty);
return RValue::get(This);
}
llvm::Value *Callee = EmitCXXOperatorMemberCallee(E, MD, This);
return EmitCXXMemberCall(MD, Callee, ReturnValue, This, /*VTT=*/0,
E->arg_begin() + 1, E->arg_end());
}
RValue CodeGenFunction::EmitCUDAKernelCallExpr(const CUDAKernelCallExpr *E,
ReturnValueSlot ReturnValue) {
return CGM.getCUDARuntime().EmitCUDAKernelCallExpr(*this, E, ReturnValue);
}
static void EmitNullBaseClassInitialization(CodeGenFunction &CGF,
llvm::Value *DestPtr,
const CXXRecordDecl *Base) {
if (Base->isEmpty())
return;
DestPtr = CGF.EmitCastToVoidPtr(DestPtr);
const ASTRecordLayout &Layout = CGF.getContext().getASTRecordLayout(Base);
CharUnits Size = Layout.getNonVirtualSize();
CharUnits Align = Layout.getNonVirtualAlign();
llvm::Value *SizeVal = CGF.CGM.getSize(Size);
// 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.
if (!CGF.CGM.getTypes().isZeroInitializable(Base)) {
llvm::Constant *NullConstant = CGF.CGM.EmitNullConstantForBase(Base);
llvm::GlobalVariable *NullVariable =
new llvm::GlobalVariable(CGF.CGM.getModule(), NullConstant->getType(),
/*isConstant=*/true,
llvm::GlobalVariable::PrivateLinkage,
NullConstant, Twine());
NullVariable->setAlignment(Align.getQuantity());
llvm::Value *SrcPtr = CGF.EmitCastToVoidPtr(NullVariable);
// Get and call the appropriate llvm.memcpy overload.
CGF.Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, Align.getQuantity());
return;
}
// 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.
CGF.Builder.CreateMemSet(DestPtr, CGF.Builder.getInt8(0), SizeVal,
Align.getQuantity());
}
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:
assert(0 && "Delegating constructor should not need zeroing");
case CXXConstructExpr::CK_Complete:
EmitNullInitialization(Dest.getAddr(), E->getType());
break;
case CXXConstructExpr::CK_VirtualBase:
case CXXConstructExpr::CK_NonVirtualBase:
EmitNullBaseClassInitialization(*this, Dest.getAddr(), 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 (getContext().getLangOptions().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 ConstantArrayType *arrayType
= getContext().getAsConstantArrayType(E->getType())) {
EmitCXXAggrConstructorCall(CD, arrayType, Dest.getAddr(),
E->arg_begin(), E->arg_end());
} else {
CXXCtorType Type = Ctor_Complete;
bool ForVirtualBase = false;
switch (E->getConstructionKind()) {
case CXXConstructExpr::CK_Delegating:
// We should be emitting a constructor; GlobalDecl will assert this
Type = CurGD.getCtorType();
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, Dest.getAddr(),
E->arg_begin(), E->arg_end());
}
}
void
CodeGenFunction::EmitSynthesizedCXXCopyCtor(llvm::Value *Dest,
llvm::Value *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->arg_begin(), E->arg_end());
}
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,
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);
// 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 four 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) we need to compute
// sizeWithoutCookie := numElements * typeSizeMultiplier
// and check whether it overflows; and
// 4) if we need a cookie, we need to compute
// size := sizeWithoutCookie + cookieSize
// and check whether it overflows.
llvm::Value *hasOverflow = 0;
// 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.
if (typeSizeMultiplier == 1)
hasOverflow = CGF.Builder.CreateICmpSLT(numElements,
llvm::ConstantInt::get(CGF.SizeTy, 0));
// Otherwise, zext up to size_t if necessary.
} else if (numElementsWidth < sizeWidth) {
numElements = CGF.Builder.CreateZExt(numElements, CGF.SizeTy);
}
assert(numElements->getType() == CGF.SizeTy);
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.CreateCall2(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.CreateCall2(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 CXXNewExpr *E,
llvm::Value *NewPtr) {
assert(E->getNumConstructorArgs() == 1 &&
"Can only have one argument to initializer of POD type.");
const Expr *Init = E->getConstructorArg(0);
QualType AllocType = E->getAllocatedType();
CharUnits Alignment = CGF.getContext().getTypeAlignInChars(AllocType);
if (!CGF.hasAggregateLLVMType(AllocType))
CGF.EmitScalarInit(Init, 0, CGF.MakeAddrLValue(NewPtr, AllocType,
Alignment),
false);
else if (AllocType->isAnyComplexType())
CGF.EmitComplexExprIntoAddr(Init, NewPtr,
AllocType.isVolatileQualified());
else {
AggValueSlot Slot
= AggValueSlot::forAddr(NewPtr, Alignment, AllocType.getQualifiers(),
AggValueSlot::IsDestructed,
AggValueSlot::DoesNotNeedGCBarriers,
AggValueSlot::IsNotAliased);
CGF.EmitAggExpr(Init, Slot);
}
}
void
CodeGenFunction::EmitNewArrayInitializer(const CXXNewExpr *E,
QualType elementType,
llvm::Value *beginPtr,
llvm::Value *numElements) {
// We have a POD type.
if (E->getNumConstructorArgs() == 0)
return;
// Check if the number of elements is constant.
bool checkZero = true;
if (llvm::ConstantInt *constNum = dyn_cast<llvm::ConstantInt>(numElements)) {
// If it's constant zero, skip the whole loop.
if (constNum->isZero()) return;
checkZero = false;
}
// Find the end of the array, hoisted out of the loop.
llvm::Value *endPtr =
Builder.CreateInBoundsGEP(beginPtr, numElements, "array.end");
// Create the continuation block.
llvm::BasicBlock *contBB = createBasicBlock("new.loop.end");
// If we need to check for zero, do so now.
if (checkZero) {
llvm::BasicBlock *nonEmptyBB = createBasicBlock("new.loop.nonempty");
llvm::Value *isEmpty = Builder.CreateICmpEQ(beginPtr, endPtr,
"array.isempty");
Builder.CreateCondBr(isEmpty, contBB, nonEmptyBB);
EmitBlock(nonEmptyBB);
}
// Enter the loop.
llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
llvm::BasicBlock *loopBB = createBasicBlock("new.loop");
EmitBlock(loopBB);
// Set up the current-element phi.
llvm::PHINode *curPtr =
Builder.CreatePHI(beginPtr->getType(), 2, "array.cur");
curPtr->addIncoming(beginPtr, entryBB);
// Enter a partial-destruction cleanup if necessary.
QualType::DestructionKind dtorKind = elementType.isDestructedType();
EHScopeStack::stable_iterator cleanup;
llvm::Instruction *cleanupDominator = 0;
if (needsEHCleanup(dtorKind)) {
pushRegularPartialArrayCleanup(beginPtr, curPtr, elementType,
getDestroyer(dtorKind));
cleanup = EHStack.stable_begin();
cleanupDominator = Builder.CreateUnreachable();
}
// Emit the initializer into this element.
StoreAnyExprIntoOneUnit(*this, E, curPtr);
// Leave the cleanup if we entered one.
if (cleanupDominator) {
DeactivateCleanupBlock(cleanup, cleanupDominator);
cleanupDominator->eraseFromParent();
}
// Advance to the next element.
llvm::Value *nextPtr = Builder.CreateConstGEP1_32(curPtr, 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);
curPtr->addIncoming(nextPtr, Builder.GetInsertBlock());
EmitBlock(contBB);
}
static void EmitZeroMemSet(CodeGenFunction &CGF, QualType T,
llvm::Value *NewPtr, llvm::Value *Size) {
CGF.EmitCastToVoidPtr(NewPtr);
CharUnits Alignment = CGF.getContext().getTypeAlignInChars(T);
CGF.Builder.CreateMemSet(NewPtr, CGF.Builder.getInt8(0), Size,
Alignment.getQuantity(), false);
}
static void EmitNewInitializer(CodeGenFunction &CGF, const CXXNewExpr *E,
QualType ElementType,
llvm::Value *NewPtr,
llvm::Value *NumElements,
llvm::Value *AllocSizeWithoutCookie) {
if (E->isArray()) {
if (CXXConstructorDecl *Ctor = E->getConstructor()) {
bool RequiresZeroInitialization = false;
if (Ctor->getParent()->hasTrivialDefaultConstructor()) {
// If new expression did not specify value-initialization, then there
// is no initialization.
if (!E->hasInitializer() || Ctor->getParent()->isEmpty())
return;
if (CGF.CGM.getTypes().isZeroInitializable(ElementType)) {
// Optimization: since zero initialization will just set the memory
// to all zeroes, generate a single memset to do it in one shot.
EmitZeroMemSet(CGF, ElementType, NewPtr, AllocSizeWithoutCookie);
return;
}
RequiresZeroInitialization = true;
}
CGF.EmitCXXAggrConstructorCall(Ctor, NumElements, NewPtr,
E->constructor_arg_begin(),
E->constructor_arg_end(),
RequiresZeroInitialization);
return;
} else if (E->getNumConstructorArgs() == 1 &&
isa<ImplicitValueInitExpr>(E->getConstructorArg(0)) &&
CGF.CGM.getTypes().isZeroInitializable(ElementType)) {
// Optimization: since zero initialization will just set the memory
// to all zeroes, generate a single memset to do it in one shot.
EmitZeroMemSet(CGF, ElementType, NewPtr, AllocSizeWithoutCookie);
return;
} else {
CGF.EmitNewArrayInitializer(E, ElementType, NewPtr, NumElements);
return;
}
}
if (CXXConstructorDecl *Ctor = E->getConstructor()) {
// Per C++ [expr.new]p15, if we have an initializer, then we're performing
// direct initialization. C++ [dcl.init]p5 requires that we
// zero-initialize storage if there are no user-declared constructors.
if (E->hasInitializer() &&
!Ctor->getParent()->hasUserDeclaredConstructor() &&
!Ctor->getParent()->isEmpty())
CGF.EmitNullInitialization(NewPtr, ElementType);
CGF.EmitCXXConstructorCall(Ctor, Ctor_Complete, /*ForVirtualBase=*/false,
NewPtr, E->constructor_arg_begin(),
E->constructor_arg_end());
return;
}
// We have a POD type.
if (E->getNumConstructorArgs() == 0)
return;
StoreAnyExprIntoOneUnit(CGF, E, NewPtr);
}
namespace {
/// A cleanup to call the given 'operator delete' function upon
/// abnormal exit from a new expression.
class CallDeleteDuringNew : 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) {
const FunctionProtoType *FPT
= OperatorDelete->getType()->getAs<FunctionProtoType>();
assert(FPT->getNumArgs() == NumPlacementArgs + 1 ||
(FPT->getNumArgs() == 2 && NumPlacementArgs == 0));
CallArgList DeleteArgs;
// The first argument is always a void*.
FunctionProtoType::arg_type_iterator AI = FPT->arg_type_begin();
DeleteArgs.add(RValue::get(Ptr), *AI++);
// A member 'operator delete' can take an extra 'size_t' argument.
if (FPT->getNumArgs() == 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'.
CGF.EmitCall(CGF.CGM.getTypes().getFunctionInfo(DeleteArgs, FPT),
CGF.CGM.GetAddrOfFunction(OperatorDelete),
ReturnValueSlot(), DeleteArgs, OperatorDelete);
}
};
/// A cleanup to call the given 'operator delete' function upon
/// abnormal exit from a new expression when the new expression is
/// conditional.
class CallDeleteDuringConditionalNew : 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) {
const FunctionProtoType *FPT
= OperatorDelete->getType()->getAs<FunctionProtoType>();
assert(FPT->getNumArgs() == NumPlacementArgs + 1 ||
(FPT->getNumArgs() == 2 && NumPlacementArgs == 0));
CallArgList DeleteArgs;
// The first argument is always a void*.
FunctionProtoType::arg_type_iterator AI = FPT->arg_type_begin();
DeleteArgs.add(Ptr.restore(CGF), *AI++);
// A member 'operator delete' can take an extra 'size_t' argument.
if (FPT->getNumArgs() == 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'.
CGF.EmitCall(CGF.CGM.getTypes().getFunctionInfo(DeleteArgs, FPT),
CGF.CGM.GetAddrOfFunction(OperatorDelete),
ReturnValueSlot(), DeleteArgs, OperatorDelete);
}
};
}
/// Enter a cleanup to call 'operator delete' if the initializer in a
/// new-expression throws.
static void EnterNewDeleteCleanup(CodeGenFunction &CGF,
const CXXNewExpr *E,
llvm::Value *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, 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));
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();
const FunctionProtoType *allocatorType =
allocator->getType()->castAs<FunctionProtoType>();
CallArgList allocatorArgs;
// The allocation size is the first argument.
QualType sizeType = getContext().getSizeType();
llvm::Value *numElements = 0;
llvm::Value *allocSizeWithoutCookie = 0;
llvm::Value *allocSize =
EmitCXXNewAllocSize(*this, E, numElements, allocSizeWithoutCookie);
allocatorArgs.add(RValue::get(allocSize), sizeType);
// Emit the rest of the arguments.
// FIXME: Ideally, this should just use EmitCallArgs.
CXXNewExpr::const_arg_iterator placementArg = E->placement_arg_begin();
// First, use the types from the function type.
// We start at 1 here because the first argument (the allocation size)
// has already been emitted.
for (unsigned i = 1, e = allocatorType->getNumArgs(); i != e;
++i, ++placementArg) {
QualType argType = allocatorType->getArgType(i);
assert(getContext().hasSameUnqualifiedType(argType.getNonReferenceType(),
placementArg->getType()) &&
"type mismatch in call argument!");
EmitCallArg(allocatorArgs, *placementArg, argType);
}
// Either we've emitted all the call args, or we have a call to a
// variadic function.
assert((placementArg == E->placement_arg_end() ||
allocatorType->isVariadic()) &&
"Extra arguments to non-variadic function!");
// If we still have any arguments, emit them using the type of the argument.
for (CXXNewExpr::const_arg_iterator placementArgsEnd = E->placement_arg_end();
placementArg != placementArgsEnd; ++placementArg) {
EmitCallArg(allocatorArgs, *placementArg, placementArg->getType());
}
// Emit the allocation call. If the allocator is a global placement
// operator, just "inline" it directly.
RValue RV;
if (allocator->isReservedGlobalPlacementOperator()) {
assert(allocatorArgs.size() == 2);
RV = allocatorArgs[1].RV;
// TODO: kill any unnecessary computations done for the size
// argument.
} else {
RV = EmitCall(CGM.getTypes().getFunctionInfo(allocatorArgs, allocatorType),
CGM.GetAddrOfFunction(allocator), ReturnValueSlot(),
allocatorArgs, allocator);
}
// 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; for this part, we inline
// CXXNewExpr::shouldNullCheckAllocation()) and we have an
// interesting initializer.
bool nullCheck = allocatorType->isNothrow(getContext()) &&
!(allocType.isPODType(getContext()) && !E->hasInitializer());
llvm::BasicBlock *nullCheckBB = 0;
llvm::BasicBlock *contBB = 0;
llvm::Value *allocation = RV.getScalarVal();
unsigned AS =
cast<llvm::PointerType>(allocation->getType())->getAddressSpace();
// 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, "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 = 0;
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 *elementPtrTy
= ConvertTypeForMem(allocType)->getPointerTo(AS);
llvm::Value *result = Builder.CreateBitCast(allocation, elementPtrTy);
EmitNewInitializer(*this, E, allocType, 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();
}
if (nullCheck) {
conditional.end(*this);
llvm::BasicBlock *notNullBB = Builder.GetInsertBlock();
EmitBlock(contBB);
llvm::PHINode *PHI = Builder.CreatePHI(result->getType(), 2);
PHI->addIncoming(result, notNullBB);
PHI->addIncoming(llvm::Constant::getNullValue(result->getType()),
nullCheckBB);
result = PHI;
}
return result;
}
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 = 0;
QualType SizeTy;
if (DeleteFTy->getNumArgs() == 2) {
SizeTy = DeleteFTy->getArgType(1);
CharUnits DeleteTypeSize = getContext().getTypeSizeInChars(DeleteTy);
Size = llvm::ConstantInt::get(ConvertType(SizeTy),
DeleteTypeSize.getQuantity());
}
QualType ArgTy = DeleteFTy->getArgType(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.
EmitCall(CGM.getTypes().getFunctionInfo(DeleteArgs, DeleteFTy),
CGM.GetAddrOfFunction(DeleteFD), ReturnValueSlot(),
DeleteArgs, DeleteFD);
}
namespace {
/// Calls the given 'operator delete' on a single object.
struct CallObjectDelete : 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) {
CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType);
}
};
}
/// Emit the code for deleting a single object.
static void EmitObjectDelete(CodeGenFunction &CGF,
const FunctionDecl *OperatorDelete,
llvm::Value *Ptr,
QualType ElementType,
bool UseGlobalDelete) {
// Find the destructor for the type, if applicable. If the
// destructor is virtual, we'll just emit the vcall and return.
const CXXDestructorDecl *Dtor = 0;
if (const RecordType *RT = ElementType->getAs<RecordType>()) {
CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
if (RD->hasDefinition() && !RD->hasTrivialDestructor()) {
Dtor = RD->getDestructor();
if (Dtor->isVirtual()) {
if (UseGlobalDelete) {
// If we're supposed to call the global delete, make sure we do so
// even if the destructor throws.
CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup,
Ptr, OperatorDelete,
ElementType);
}
llvm::Type *Ty =
CGF.getTypes().GetFunctionType(CGF.getTypes().getFunctionInfo(Dtor,
Dtor_Complete),
/*isVariadic=*/false);
llvm::Value *Callee
= CGF.BuildVirtualCall(Dtor,
UseGlobalDelete? Dtor_Complete : Dtor_Deleting,
Ptr, Ty);
CGF.EmitCXXMemberCall(Dtor, Callee, ReturnValueSlot(), Ptr, /*VTT=*/0,
0, 0);
if (UseGlobalDelete) {
CGF.PopCleanupBlock();
}
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.
CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup,
Ptr, OperatorDelete, ElementType);
if (Dtor)
CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
/*ForVirtualBase=*/false, Ptr);
else if (CGF.getLangOptions().ObjCAutoRefCount &&
ElementType->isObjCLifetimeType()) {
switch (ElementType.getObjCLifetime()) {
case Qualifiers::OCL_None:
case Qualifiers::OCL_ExplicitNone:
case Qualifiers::OCL_Autoreleasing:
break;
case Qualifiers::OCL_Strong: {
// Load the pointer value.
llvm::Value *PtrValue = CGF.Builder.CreateLoad(Ptr,
ElementType.isVolatileQualified());
CGF.EmitARCRelease(PtrValue, /*precise*/ true);
break;
}
case Qualifiers::OCL_Weak:
CGF.EmitARCDestroyWeak(Ptr);
break;
}
}
CGF.PopCleanupBlock();
}
namespace {
/// Calls the given 'operator delete' on an array of objects.
struct CallArrayDelete : 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) {
const FunctionProtoType *DeleteFTy =
OperatorDelete->getType()->getAs<FunctionProtoType>();
assert(DeleteFTy->getNumArgs() == 1 || DeleteFTy->getNumArgs() == 2);
CallArgList Args;
// Pass the pointer as the first argument.
QualType VoidPtrTy = DeleteFTy->getArgType(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->getNumArgs() == 2) {
QualType size_t = DeleteFTy->getArgType(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());
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.
CGF.EmitCall(CGF.getTypes().getFunctionInfo(Args, DeleteFTy),
CGF.CGM.GetAddrOfFunction(OperatorDelete),
ReturnValueSlot(), Args, OperatorDelete);
}
};
}
/// Emit the code for deleting an array of objects.
static void EmitArrayDelete(CodeGenFunction &CGF,
const CXXDeleteExpr *E,
llvm::Value *deletedPtr,
QualType elementType) {
llvm::Value *numElements = 0;
llvm::Value *allocatedPtr = 0;
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!");
llvm::Value *arrayEnd =
CGF.Builder.CreateInBoundsGEP(deletedPtr, 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(deletedPtr, arrayEnd, elementType,
CGF.getDestroyer(dtorKind),
/*checkZeroLength*/ true,
CGF.needsEHCleanup(dtorKind));
}
// Pop the cleanup block.
CGF.PopCleanupBlock();
}
void CodeGenFunction::EmitCXXDeleteExpr(const CXXDeleteExpr *E) {
// Get at the argument before we performed the implicit conversion
// to void*.
const Expr *Arg = E->getArgument();
while (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) {
if (ICE->getCastKind() != CK_UserDefinedConversion &&
ICE->getType()->isVoidPointerType())
Arg = ICE->getSubExpr();
else
break;
}
llvm::Value *Ptr = EmitScalarExpr(Arg);
// Null check the pointer.
llvm::BasicBlock *DeleteNotNull = createBasicBlock("delete.notnull");
llvm::BasicBlock *DeleteEnd = createBasicBlock("delete.end");
llvm::Value *IsNull = Builder.CreateIsNull(Ptr, "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 = Builder.CreateInBoundsGEP(Ptr, GEP, "del.first");
}
assert(ConvertTypeForMem(DeleteTy) ==
cast<llvm::PointerType>(Ptr->getType())->getElementType());
if (E->isArrayForm()) {
EmitArrayDelete(*this, E, Ptr, DeleteTy);
} else {
EmitObjectDelete(*this, E->getOperatorDelete(), Ptr, DeleteTy,
E->isGlobalDelete());
}
EmitBlock(DeleteEnd);
}
static llvm::Constant *getBadTypeidFn(CodeGenFunction &CGF) {
// void __cxa_bad_typeid();
llvm::Type *VoidTy = llvm::Type::getVoidTy(CGF.getLLVMContext());
llvm::FunctionType *FTy =
llvm::FunctionType::get(VoidTy, false);
return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_bad_typeid");
}
static void EmitBadTypeidCall(CodeGenFunction &CGF) {
llvm::Value *Fn = getBadTypeidFn(CGF);
CGF.EmitCallOrInvoke(Fn).setDoesNotReturn();
CGF.Builder.CreateUnreachable();
}
static llvm::Value *EmitTypeidFromVTable(CodeGenFunction &CGF,
const Expr *E,
llvm::Type *StdTypeInfoPtrTy) {
// Get the vtable pointer.
llvm::Value *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.
if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E->IgnoreParens())) {
if (UO->getOpcode() == UO_Deref) {
llvm::BasicBlock *BadTypeidBlock =
CGF.createBasicBlock("typeid.bad_typeid");
llvm::BasicBlock *EndBlock =
CGF.createBasicBlock("typeid.end");
llvm::Value *IsNull = CGF.Builder.CreateIsNull(ThisPtr);
CGF.Builder.CreateCondBr(IsNull, BadTypeidBlock, EndBlock);
CGF.EmitBlock(BadTypeidBlock);
EmitBadTypeidCall(CGF);
CGF.EmitBlock(EndBlock);
}
}
llvm::Value *Value = CGF.GetVTablePtr(ThisPtr,
StdTypeInfoPtrTy->getPointerTo());
// Load the type info.
Value = CGF.Builder.CreateConstInBoundsGEP1_64(Value, -1ULL);
return CGF.Builder.CreateLoad(Value);
}
llvm::Value *CodeGenFunction::EmitCXXTypeidExpr(const CXXTypeidExpr *E) {
llvm::Type *StdTypeInfoPtrTy =
ConvertType(E->getType())->getPointerTo();
if (E->isTypeOperand()) {
llvm::Constant *TypeInfo =
CGM.GetAddrOfRTTIDescriptor(E->getTypeOperand());
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->getExprOperand()->isGLValue()) {
if (const RecordType *RT =
E->getExprOperand()->getType()->getAs<RecordType>()) {
const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
if (RD->isPolymorphic())
return EmitTypeidFromVTable(*this, E->getExprOperand(),
StdTypeInfoPtrTy);
}
}
QualType OperandTy = E->getExprOperand()->getType();
return Builder.CreateBitCast(CGM.GetAddrOfRTTIDescriptor(OperandTy),
StdTypeInfoPtrTy);
}
static llvm::Constant *getDynamicCastFn(CodeGenFunction &CGF) {
// void *__dynamic_cast(const void *sub,
// const abi::__class_type_info *src,
// const abi::__class_type_info *dst,
// std::ptrdiff_t src2dst_offset);
llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGF.getLLVMContext());
llvm::Type *PtrDiffTy =
CGF.ConvertType(CGF.getContext().getPointerDiffType());
llvm::Type *Args[4] = { Int8PtrTy, Int8PtrTy, Int8PtrTy, PtrDiffTy };
llvm::FunctionType *FTy =
llvm::FunctionType::get(Int8PtrTy, Args, false);
return CGF.CGM.CreateRuntimeFunction(FTy, "__dynamic_cast");
}
static llvm::Constant *getBadCastFn(CodeGenFunction &CGF) {
// void __cxa_bad_cast();
llvm::Type *VoidTy = llvm::Type::getVoidTy(CGF.getLLVMContext());
llvm::FunctionType *FTy =
llvm::FunctionType::get(VoidTy, false);
return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_bad_cast");
}
static void EmitBadCastCall(CodeGenFunction &CGF) {
llvm::Value *Fn = getBadCastFn(CGF);
CGF.EmitCallOrInvoke(Fn).setDoesNotReturn();
CGF.Builder.CreateUnreachable();
}
static llvm::Value *
EmitDynamicCastCall(CodeGenFunction &CGF, llvm::Value *Value,
QualType SrcTy, QualType DestTy,
llvm::BasicBlock *CastEnd) {
llvm::Type *PtrDiffLTy =
CGF.ConvertType(CGF.getContext().getPointerDiffType());
llvm::Type *DestLTy = CGF.ConvertType(DestTy);
if (const PointerType *PTy = DestTy->getAs<PointerType>()) {
if (PTy->getPointeeType()->isVoidType()) {
// 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.
// Get the vtable pointer.
llvm::Value *VTable = CGF.GetVTablePtr(Value, PtrDiffLTy->getPointerTo());
// Get the offset-to-top from the vtable.
llvm::Value *OffsetToTop =
CGF.Builder.CreateConstInBoundsGEP1_64(VTable, -2ULL);
OffsetToTop = CGF.Builder.CreateLoad(OffsetToTop, "offset.to.top");
// Finally, add the offset to the pointer.
Value = CGF.EmitCastToVoidPtr(Value);
Value = CGF.Builder.CreateInBoundsGEP(Value, OffsetToTop);
return CGF.Builder.CreateBitCast(Value, DestLTy);
}
}
QualType SrcRecordTy;
QualType DestRecordTy;
if (const PointerType *DestPTy = DestTy->getAs<PointerType>()) {
SrcRecordTy = SrcTy->castAs<PointerType>()->getPointeeType();
DestRecordTy = DestPTy->getPointeeType();
} else {
SrcRecordTy = SrcTy;
DestRecordTy = DestTy->castAs<ReferenceType>()->getPointeeType();
}
assert(SrcRecordTy->isRecordType() && "source type must be a record type!");
assert(DestRecordTy->isRecordType() && "dest type must be a record type!");
llvm::Value *SrcRTTI =
CGF.CGM.GetAddrOfRTTIDescriptor(SrcRecordTy.getUnqualifiedType());
llvm::Value *DestRTTI =
CGF.CGM.GetAddrOfRTTIDescriptor(DestRecordTy.getUnqualifiedType());
// FIXME: Actually compute a hint here.
llvm::Value *OffsetHint = llvm::ConstantInt::get(PtrDiffLTy, -1ULL);
// Emit the call to __dynamic_cast.
Value = CGF.EmitCastToVoidPtr(Value);
Value = CGF.Builder.CreateCall4(getDynamicCastFn(CGF), Value,
SrcRTTI, DestRTTI, OffsetHint);
Value = CGF.Builder.CreateBitCast(Value, DestLTy);
/// C++ [expr.dynamic.cast]p9:
/// A failed cast to reference type throws std::bad_cast
if (DestTy->isReferenceType()) {
llvm::BasicBlock *BadCastBlock =
CGF.createBasicBlock("dynamic_cast.bad_cast");
llvm::Value *IsNull = CGF.Builder.CreateIsNull(Value);
CGF.Builder.CreateCondBr(IsNull, BadCastBlock, CastEnd);
CGF.EmitBlock(BadCastBlock);
EmitBadCastCall(CGF);
}
return Value;
}
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
EmitBadCastCall(CGF);
CGF.EmitBlock(CGF.createBasicBlock("dynamic_cast.end"));
return llvm::UndefValue::get(DestLTy);
}
llvm::Value *CodeGenFunction::EmitDynamicCast(llvm::Value *Value,
const CXXDynamicCastExpr *DCE) {
QualType DestTy = DCE->getTypeAsWritten();
if (DCE->isAlwaysNull())
return EmitDynamicCastToNull(*this, DestTy);
QualType SrcTy = DCE->getSubExpr()->getType();
// 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 = SrcTy->isPointerType();
llvm::BasicBlock *CastNull = 0;
llvm::BasicBlock *CastNotNull = 0;
llvm::BasicBlock *CastEnd = createBasicBlock("dynamic_cast.end");
if (ShouldNullCheckSrcValue) {
CastNull = createBasicBlock("dynamic_cast.null");
CastNotNull = createBasicBlock("dynamic_cast.notnull");
llvm::Value *IsNull = Builder.CreateIsNull(Value);
Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
EmitBlock(CastNotNull);
}
Value = EmitDynamicCastCall(*this, Value, SrcTy, DestTy, CastEnd);
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;
}
Reference in New Issue View Git Blame Copy Permalink