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

1625 lines
64 KiB
C++

//===--- CGClass.cpp - Emit LLVM Code for C++ classes ---------------------===//
//
// 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 C++ code generation of classes
//
//===----------------------------------------------------------------------===//
#include "CodeGenFunction.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/RecordLayout.h"
#include "clang/AST/StmtCXX.h"
using namespace clang;
using namespace CodeGen;
static uint64_t
ComputeNonVirtualBaseClassOffset(ASTContext &Context,
const CXXBasePath &Path,
unsigned Start) {
uint64_t Offset = 0;
for (unsigned i = Start, e = Path.size(); i != e; ++i) {
const CXXBasePathElement& Element = Path[i];
// Get the layout.
const ASTRecordLayout &Layout = Context.getASTRecordLayout(Element.Class);
const CXXBaseSpecifier *BS = Element.Base;
assert(!BS->isVirtual() && "Should not see virtual bases here!");
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(BS->getType()->getAs<RecordType>()->getDecl());
// Add the offset.
Offset += Layout.getBaseClassOffset(Base) / 8;
}
return Offset;
}
llvm::Constant *
CodeGenModule::GetNonVirtualBaseClassOffset(const CXXRecordDecl *Class,
const CXXRecordDecl *BaseClass) {
if (Class == BaseClass)
return 0;
CXXBasePaths Paths(/*FindAmbiguities=*/false,
/*RecordPaths=*/true, /*DetectVirtual=*/false);
if (!const_cast<CXXRecordDecl *>(Class)->
isDerivedFrom(const_cast<CXXRecordDecl *>(BaseClass), Paths)) {
assert(false && "Class must be derived from the passed in base class!");
return 0;
}
uint64_t Offset = ComputeNonVirtualBaseClassOffset(getContext(),
Paths.front(), 0);
if (!Offset)
return 0;
const llvm::Type *PtrDiffTy =
Types.ConvertType(getContext().getPointerDiffType());
return llvm::ConstantInt::get(PtrDiffTy, Offset);
}
// FIXME: This probably belongs in CGVtable, but it relies on
// the static function ComputeNonVirtualBaseClassOffset, so we should make that
// a CodeGenModule member function as well.
ThunkAdjustment
CodeGenModule::ComputeThunkAdjustment(const CXXRecordDecl *ClassDecl,
const CXXRecordDecl *BaseClassDecl) {
CXXBasePaths Paths(/*FindAmbiguities=*/false,
/*RecordPaths=*/true, /*DetectVirtual=*/false);
if (!const_cast<CXXRecordDecl *>(ClassDecl)->
isDerivedFrom(const_cast<CXXRecordDecl *>(BaseClassDecl), Paths)) {
assert(false && "Class must be derived from the passed in base class!");
return ThunkAdjustment();
}
unsigned Start = 0;
uint64_t VirtualOffset = 0;
const CXXBasePath &Path = Paths.front();
const CXXRecordDecl *VBase = 0;
for (unsigned i = 0, e = Path.size(); i != e; ++i) {
const CXXBasePathElement& Element = Path[i];
if (Element.Base->isVirtual()) {
Start = i+1;
QualType VBaseType = Element.Base->getType();
VBase = cast<CXXRecordDecl>(VBaseType->getAs<RecordType>()->getDecl());
}
}
if (VBase)
VirtualOffset =
getVtableInfo().getVirtualBaseOffsetOffset(ClassDecl, BaseClassDecl);
uint64_t Offset =
ComputeNonVirtualBaseClassOffset(getContext(), Paths.front(), Start);
return ThunkAdjustment(Offset, VirtualOffset);
}
/// Gets the address of a virtual base class within a complete object.
/// This should only be used for (1) non-virtual bases or (2) virtual bases
/// when the type is known to be complete (e.g. in complete destructors).
///
/// The object pointed to by 'This' is assumed to be non-null.
llvm::Value *
CodeGenFunction::GetAddressOfBaseOfCompleteClass(llvm::Value *This,
bool isBaseVirtual,
const CXXRecordDecl *Derived,
const CXXRecordDecl *Base) {
// 'this' must be a pointer (in some address space) to Derived.
assert(This->getType()->isPointerTy() &&
cast<llvm::PointerType>(This->getType())->getElementType()
== ConvertType(Derived));
// Compute the offset of the virtual base.
uint64_t Offset;
const ASTRecordLayout &Layout = getContext().getASTRecordLayout(Derived);
if (isBaseVirtual)
Offset = Layout.getVBaseClassOffset(Base);
else
Offset = Layout.getBaseClassOffset(Base);
// Shift and cast down to the base type.
// TODO: for complete types, this should be possible with a GEP.
llvm::Value *V = This;
if (Offset) {
const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(getLLVMContext());
V = Builder.CreateBitCast(V, Int8PtrTy);
V = Builder.CreateConstInBoundsGEP1_64(V, Offset / 8);
}
V = Builder.CreateBitCast(V, ConvertType(Base)->getPointerTo());
return V;
}
llvm::Value *
CodeGenFunction::GetAddressOfBaseClass(llvm::Value *Value,
const CXXRecordDecl *Class,
const CXXRecordDecl *BaseClass,
bool NullCheckValue) {
QualType BTy =
getContext().getCanonicalType(
getContext().getTypeDeclType(BaseClass));
const llvm::Type *BasePtrTy = llvm::PointerType::getUnqual(ConvertType(BTy));
if (Class == BaseClass) {
// Just cast back.
return Builder.CreateBitCast(Value, BasePtrTy);
}
CXXBasePaths Paths(/*FindAmbiguities=*/false,
/*RecordPaths=*/true, /*DetectVirtual=*/false);
if (!const_cast<CXXRecordDecl *>(Class)->
isDerivedFrom(const_cast<CXXRecordDecl *>(BaseClass), Paths)) {
assert(false && "Class must be derived from the passed in base class!");
return 0;
}
unsigned Start = 0;
llvm::Value *VirtualOffset = 0;
const CXXBasePath &Path = Paths.front();
const CXXRecordDecl *VBase = 0;
for (unsigned i = 0, e = Path.size(); i != e; ++i) {
const CXXBasePathElement& Element = Path[i];
if (Element.Base->isVirtual()) {
Start = i+1;
QualType VBaseType = Element.Base->getType();
VBase = cast<CXXRecordDecl>(VBaseType->getAs<RecordType>()->getDecl());
}
}
uint64_t Offset =
ComputeNonVirtualBaseClassOffset(getContext(), Paths.front(), Start);
if (!Offset && !VBase) {
// Just cast back.
return Builder.CreateBitCast(Value, BasePtrTy);
}
llvm::BasicBlock *CastNull = 0;
llvm::BasicBlock *CastNotNull = 0;
llvm::BasicBlock *CastEnd = 0;
if (NullCheckValue) {
CastNull = createBasicBlock("cast.null");
CastNotNull = createBasicBlock("cast.notnull");
CastEnd = createBasicBlock("cast.end");
llvm::Value *IsNull =
Builder.CreateICmpEQ(Value,
llvm::Constant::getNullValue(Value->getType()));
Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
EmitBlock(CastNotNull);
}
if (VBase)
VirtualOffset = GetVirtualBaseClassOffset(Value, Class, VBase);
const llvm::Type *PtrDiffTy = ConvertType(getContext().getPointerDiffType());
llvm::Value *NonVirtualOffset = 0;
if (Offset)
NonVirtualOffset = llvm::ConstantInt::get(PtrDiffTy, Offset);
llvm::Value *BaseOffset;
if (VBase) {
if (NonVirtualOffset)
BaseOffset = Builder.CreateAdd(VirtualOffset, NonVirtualOffset);
else
BaseOffset = VirtualOffset;
} else
BaseOffset = NonVirtualOffset;
// Apply the base offset.
const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(getLLVMContext());
Value = Builder.CreateBitCast(Value, Int8PtrTy);
Value = Builder.CreateGEP(Value, BaseOffset, "add.ptr");
// Cast back.
Value = Builder.CreateBitCast(Value, BasePtrTy);
if (NullCheckValue) {
Builder.CreateBr(CastEnd);
EmitBlock(CastNull);
Builder.CreateBr(CastEnd);
EmitBlock(CastEnd);
llvm::PHINode *PHI = Builder.CreatePHI(Value->getType());
PHI->reserveOperandSpace(2);
PHI->addIncoming(Value, CastNotNull);
PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()),
CastNull);
Value = PHI;
}
return Value;
}
llvm::Value *
CodeGenFunction::GetAddressOfDerivedClass(llvm::Value *Value,
const CXXRecordDecl *Class,
const CXXRecordDecl *DerivedClass,
bool NullCheckValue) {
QualType DerivedTy =
getContext().getCanonicalType(
getContext().getTypeDeclType(const_cast<CXXRecordDecl*>(DerivedClass)));
const llvm::Type *DerivedPtrTy = ConvertType(DerivedTy)->getPointerTo();
if (Class == DerivedClass) {
// Just cast back.
return Builder.CreateBitCast(Value, DerivedPtrTy);
}
llvm::Value *NonVirtualOffset =
CGM.GetNonVirtualBaseClassOffset(DerivedClass, Class);
if (!NonVirtualOffset) {
// No offset, we can just cast back.
return Builder.CreateBitCast(Value, DerivedPtrTy);
}
llvm::BasicBlock *CastNull = 0;
llvm::BasicBlock *CastNotNull = 0;
llvm::BasicBlock *CastEnd = 0;
if (NullCheckValue) {
CastNull = createBasicBlock("cast.null");
CastNotNull = createBasicBlock("cast.notnull");
CastEnd = createBasicBlock("cast.end");
llvm::Value *IsNull =
Builder.CreateICmpEQ(Value,
llvm::Constant::getNullValue(Value->getType()));
Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
EmitBlock(CastNotNull);
}
// Apply the offset.
Value = Builder.CreatePtrToInt(Value, NonVirtualOffset->getType());
Value = Builder.CreateSub(Value, NonVirtualOffset);
Value = Builder.CreateIntToPtr(Value, DerivedPtrTy);
// Just cast.
Value = Builder.CreateBitCast(Value, DerivedPtrTy);
if (NullCheckValue) {
Builder.CreateBr(CastEnd);
EmitBlock(CastNull);
Builder.CreateBr(CastEnd);
EmitBlock(CastEnd);
llvm::PHINode *PHI = Builder.CreatePHI(Value->getType());
PHI->reserveOperandSpace(2);
PHI->addIncoming(Value, CastNotNull);
PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()),
CastNull);
Value = PHI;
}
return Value;
}
/// EmitClassAggrMemberwiseCopy - This routine generates code to copy a class
/// array of objects from SrcValue to DestValue. Copying can be either a bitwise
/// copy or via a copy constructor call.
// FIXME. Consolidate this with EmitCXXAggrConstructorCall.
void CodeGenFunction::EmitClassAggrMemberwiseCopy(llvm::Value *Dest,
llvm::Value *Src,
const ArrayType *Array,
const CXXRecordDecl *BaseClassDecl,
QualType Ty) {
const ConstantArrayType *CA = dyn_cast<ConstantArrayType>(Array);
assert(CA && "VLA cannot be copied over");
bool BitwiseCopy = BaseClassDecl->hasTrivialCopyConstructor();
// Create a temporary for the loop index and initialize it with 0.
llvm::Value *IndexPtr = CreateTempAlloca(llvm::Type::getInt64Ty(VMContext),
"loop.index");
llvm::Value* zeroConstant =
llvm::Constant::getNullValue(llvm::Type::getInt64Ty(VMContext));
Builder.CreateStore(zeroConstant, IndexPtr);
// Start the loop with a block that tests the condition.
llvm::BasicBlock *CondBlock = createBasicBlock("for.cond");
llvm::BasicBlock *AfterFor = createBasicBlock("for.end");
EmitBlock(CondBlock);
llvm::BasicBlock *ForBody = createBasicBlock("for.body");
// Generate: if (loop-index < number-of-elements fall to the loop body,
// otherwise, go to the block after the for-loop.
uint64_t NumElements = getContext().getConstantArrayElementCount(CA);
llvm::Value * NumElementsPtr =
llvm::ConstantInt::get(llvm::Type::getInt64Ty(VMContext), NumElements);
llvm::Value *Counter = Builder.CreateLoad(IndexPtr);
llvm::Value *IsLess = Builder.CreateICmpULT(Counter, NumElementsPtr,
"isless");
// If the condition is true, execute the body.
Builder.CreateCondBr(IsLess, ForBody, AfterFor);
EmitBlock(ForBody);
llvm::BasicBlock *ContinueBlock = createBasicBlock("for.inc");
// Inside the loop body, emit the constructor call on the array element.
Counter = Builder.CreateLoad(IndexPtr);
Src = Builder.CreateInBoundsGEP(Src, Counter, "srcaddress");
Dest = Builder.CreateInBoundsGEP(Dest, Counter, "destaddress");
if (BitwiseCopy)
EmitAggregateCopy(Dest, Src, Ty);
else if (CXXConstructorDecl *BaseCopyCtor =
BaseClassDecl->getCopyConstructor(getContext(), 0)) {
llvm::Value *Callee = CGM.GetAddrOfCXXConstructor(BaseCopyCtor,
Ctor_Complete);
CallArgList CallArgs;
// Push the this (Dest) ptr.
CallArgs.push_back(std::make_pair(RValue::get(Dest),
BaseCopyCtor->getThisType(getContext())));
// Push the Src ptr.
CallArgs.push_back(std::make_pair(RValue::get(Src),
BaseCopyCtor->getParamDecl(0)->getType()));
const FunctionProtoType *FPT
= BaseCopyCtor->getType()->getAs<FunctionProtoType>();
EmitCall(CGM.getTypes().getFunctionInfo(CallArgs, FPT),
Callee, ReturnValueSlot(), CallArgs, BaseCopyCtor);
}
EmitBlock(ContinueBlock);
// Emit the increment of the loop counter.
llvm::Value *NextVal = llvm::ConstantInt::get(Counter->getType(), 1);
Counter = Builder.CreateLoad(IndexPtr);
NextVal = Builder.CreateAdd(Counter, NextVal, "inc");
Builder.CreateStore(NextVal, IndexPtr);
// Finally, branch back up to the condition for the next iteration.
EmitBranch(CondBlock);
// Emit the fall-through block.
EmitBlock(AfterFor, true);
}
/// EmitClassAggrCopyAssignment - This routine generates code to assign a class
/// array of objects from SrcValue to DestValue. Assignment can be either a
/// bitwise assignment or via a copy assignment operator function call.
/// FIXME. This can be consolidated with EmitClassAggrMemberwiseCopy
void CodeGenFunction::EmitClassAggrCopyAssignment(llvm::Value *Dest,
llvm::Value *Src,
const ArrayType *Array,
const CXXRecordDecl *BaseClassDecl,
QualType Ty) {
const ConstantArrayType *CA = dyn_cast<ConstantArrayType>(Array);
assert(CA && "VLA cannot be asssigned");
bool BitwiseAssign = BaseClassDecl->hasTrivialCopyAssignment();
// Create a temporary for the loop index and initialize it with 0.
llvm::Value *IndexPtr = CreateTempAlloca(llvm::Type::getInt64Ty(VMContext),
"loop.index");
llvm::Value* zeroConstant =
llvm::Constant::getNullValue(llvm::Type::getInt64Ty(VMContext));
Builder.CreateStore(zeroConstant, IndexPtr);
// Start the loop with a block that tests the condition.
llvm::BasicBlock *CondBlock = createBasicBlock("for.cond");
llvm::BasicBlock *AfterFor = createBasicBlock("for.end");
EmitBlock(CondBlock);
llvm::BasicBlock *ForBody = createBasicBlock("for.body");
// Generate: if (loop-index < number-of-elements fall to the loop body,
// otherwise, go to the block after the for-loop.
uint64_t NumElements = getContext().getConstantArrayElementCount(CA);
llvm::Value * NumElementsPtr =
llvm::ConstantInt::get(llvm::Type::getInt64Ty(VMContext), NumElements);
llvm::Value *Counter = Builder.CreateLoad(IndexPtr);
llvm::Value *IsLess = Builder.CreateICmpULT(Counter, NumElementsPtr,
"isless");
// If the condition is true, execute the body.
Builder.CreateCondBr(IsLess, ForBody, AfterFor);
EmitBlock(ForBody);
llvm::BasicBlock *ContinueBlock = createBasicBlock("for.inc");
// Inside the loop body, emit the assignment operator call on array element.
Counter = Builder.CreateLoad(IndexPtr);
Src = Builder.CreateInBoundsGEP(Src, Counter, "srcaddress");
Dest = Builder.CreateInBoundsGEP(Dest, Counter, "destaddress");
const CXXMethodDecl *MD = 0;
if (BitwiseAssign)
EmitAggregateCopy(Dest, Src, Ty);
else {
BaseClassDecl->hasConstCopyAssignment(getContext(), MD);
assert(MD && "EmitClassAggrCopyAssignment - No user assign");
const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
const llvm::Type *LTy =
CGM.getTypes().GetFunctionType(CGM.getTypes().getFunctionInfo(MD),
FPT->isVariadic());
llvm::Constant *Callee = CGM.GetAddrOfFunction(MD, LTy);
CallArgList CallArgs;
// Push the this (Dest) ptr.
CallArgs.push_back(std::make_pair(RValue::get(Dest),
MD->getThisType(getContext())));
// Push the Src ptr.
QualType SrcTy = MD->getParamDecl(0)->getType();
RValue SrcValue = SrcTy->isReferenceType() ? RValue::get(Src) :
RValue::getAggregate(Src);
CallArgs.push_back(std::make_pair(SrcValue, SrcTy));
EmitCall(CGM.getTypes().getFunctionInfo(CallArgs, FPT),
Callee, ReturnValueSlot(), CallArgs, MD);
}
EmitBlock(ContinueBlock);
// Emit the increment of the loop counter.
llvm::Value *NextVal = llvm::ConstantInt::get(Counter->getType(), 1);
Counter = Builder.CreateLoad(IndexPtr);
NextVal = Builder.CreateAdd(Counter, NextVal, "inc");
Builder.CreateStore(NextVal, IndexPtr);
// Finally, branch back up to the condition for the next iteration.
EmitBranch(CondBlock);
// Emit the fall-through block.
EmitBlock(AfterFor, true);
}
/// GetVTTParameter - Return the VTT parameter that should be passed to a
/// base constructor/destructor with virtual bases.
static llvm::Value *GetVTTParameter(CodeGenFunction &CGF, GlobalDecl GD) {
if (!CGVtableInfo::needsVTTParameter(GD)) {
// This constructor/destructor does not need a VTT parameter.
return 0;
}
const CXXRecordDecl *RD = cast<CXXMethodDecl>(CGF.CurFuncDecl)->getParent();
const CXXRecordDecl *Base = cast<CXXMethodDecl>(GD.getDecl())->getParent();
llvm::Value *VTT;
uint64_t SubVTTIndex;
// If the record matches the base, this is the complete ctor/dtor
// variant calling the base variant in a class with virtual bases.
if (RD == Base) {
assert(!CGVtableInfo::needsVTTParameter(CGF.CurGD) &&
"doing no-op VTT offset in base dtor/ctor?");
SubVTTIndex = 0;
} else {
SubVTTIndex = CGF.CGM.getVtableInfo().getSubVTTIndex(RD, Base);
assert(SubVTTIndex != 0 && "Sub-VTT index must be greater than zero!");
}
if (CGVtableInfo::needsVTTParameter(CGF.CurGD)) {
// A VTT parameter was passed to the constructor, use it.
VTT = CGF.LoadCXXVTT();
VTT = CGF.Builder.CreateConstInBoundsGEP1_64(VTT, SubVTTIndex);
} else {
// We're the complete constructor, so get the VTT by name.
VTT = CGF.CGM.getVtableInfo().getVTT(RD);
VTT = CGF.Builder.CreateConstInBoundsGEP2_64(VTT, 0, SubVTTIndex);
}
return VTT;
}
/// EmitClassMemberwiseCopy - This routine generates code to copy a class
/// object from SrcValue to DestValue. Copying can be either a bitwise copy
/// or via a copy constructor call.
void CodeGenFunction::EmitClassMemberwiseCopy(
llvm::Value *Dest, llvm::Value *Src,
const CXXRecordDecl *ClassDecl,
const CXXRecordDecl *BaseClassDecl, QualType Ty) {
CXXCtorType CtorType = Ctor_Complete;
if (ClassDecl) {
Dest = GetAddressOfBaseClass(Dest, ClassDecl, BaseClassDecl,
/*NullCheckValue=*/false);
Src = GetAddressOfBaseClass(Src, ClassDecl, BaseClassDecl,
/*NullCheckValue=*/false);
// We want to call the base constructor.
CtorType = Ctor_Base;
}
if (BaseClassDecl->hasTrivialCopyConstructor()) {
EmitAggregateCopy(Dest, Src, Ty);
return;
}
if (CXXConstructorDecl *BaseCopyCtor =
BaseClassDecl->getCopyConstructor(getContext(), 0)) {
llvm::Value *Callee = CGM.GetAddrOfCXXConstructor(BaseCopyCtor, CtorType);
CallArgList CallArgs;
// Push the this (Dest) ptr.
CallArgs.push_back(std::make_pair(RValue::get(Dest),
BaseCopyCtor->getThisType(getContext())));
// Push the VTT parameter, if necessary.
if (llvm::Value *VTT =
GetVTTParameter(*this, GlobalDecl(BaseCopyCtor, CtorType))) {
QualType T = getContext().getPointerType(getContext().VoidPtrTy);
CallArgs.push_back(std::make_pair(RValue::get(VTT), T));
}
// Push the Src ptr.
CallArgs.push_back(std::make_pair(RValue::get(Src),
BaseCopyCtor->getParamDecl(0)->getType()));
const FunctionProtoType *FPT =
BaseCopyCtor->getType()->getAs<FunctionProtoType>();
EmitCall(CGM.getTypes().getFunctionInfo(CallArgs, FPT),
Callee, ReturnValueSlot(), CallArgs, BaseCopyCtor);
}
}
/// EmitClassCopyAssignment - This routine generates code to copy assign a class
/// object from SrcValue to DestValue. Assignment can be either a bitwise
/// assignment of via an assignment operator call.
// FIXME. Consolidate this with EmitClassMemberwiseCopy as they share a lot.
void CodeGenFunction::EmitClassCopyAssignment(
llvm::Value *Dest, llvm::Value *Src,
const CXXRecordDecl *ClassDecl,
const CXXRecordDecl *BaseClassDecl,
QualType Ty) {
if (ClassDecl) {
Dest = GetAddressOfBaseClass(Dest, ClassDecl, BaseClassDecl,
/*NullCheckValue=*/false);
Src = GetAddressOfBaseClass(Src, ClassDecl, BaseClassDecl,
/*NullCheckValue=*/false);
}
if (BaseClassDecl->hasTrivialCopyAssignment()) {
EmitAggregateCopy(Dest, Src, Ty);
return;
}
const CXXMethodDecl *MD = 0;
BaseClassDecl->hasConstCopyAssignment(getContext(), MD);
assert(MD && "EmitClassCopyAssignment - missing copy assign");
const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
const llvm::Type *LTy =
CGM.getTypes().GetFunctionType(CGM.getTypes().getFunctionInfo(MD),
FPT->isVariadic());
llvm::Constant *Callee = CGM.GetAddrOfFunction(MD, LTy);
CallArgList CallArgs;
// Push the this (Dest) ptr.
CallArgs.push_back(std::make_pair(RValue::get(Dest),
MD->getThisType(getContext())));
// Push the Src ptr.
QualType SrcTy = MD->getParamDecl(0)->getType();
RValue SrcValue = SrcTy->isReferenceType() ? RValue::get(Src) :
RValue::getAggregate(Src);
CallArgs.push_back(std::make_pair(SrcValue, SrcTy));
EmitCall(CGM.getTypes().getFunctionInfo(CallArgs, FPT),
Callee, ReturnValueSlot(), CallArgs, MD);
}
/// SynthesizeCXXCopyConstructor - This routine implicitly defines body of a
/// copy constructor, in accordance with section 12.8 (p7 and p8) of C++03
/// The implicitly-defined copy constructor for class X performs a memberwise
/// copy of its subobjects. The order of copying is the same as the order of
/// initialization of bases and members in a user-defined constructor
/// Each subobject is copied in the manner appropriate to its type:
/// if the subobject is of class type, the copy constructor for the class is
/// used;
/// if the subobject is an array, each element is copied, in the manner
/// appropriate to the element type;
/// if the subobject is of scalar type, the built-in assignment operator is
/// used.
/// Virtual base class subobjects shall be copied only once by the
/// implicitly-defined copy constructor
void
CodeGenFunction::SynthesizeCXXCopyConstructor(const FunctionArgList &Args) {
const CXXConstructorDecl *Ctor = cast<CXXConstructorDecl>(CurGD.getDecl());
const CXXRecordDecl *ClassDecl = Ctor->getParent();
assert(!ClassDecl->hasUserDeclaredCopyConstructor() &&
"SynthesizeCXXCopyConstructor - copy constructor has definition already");
assert(!Ctor->isTrivial() && "shouldn't need to generate trivial ctor");
FunctionArgList::const_iterator i = Args.begin();
const VarDecl *ThisArg = i->first;
llvm::Value *ThisObj = GetAddrOfLocalVar(ThisArg);
llvm::Value *LoadOfThis = Builder.CreateLoad(ThisObj, "this");
const VarDecl *SrcArg = (i+1)->first;
llvm::Value *SrcObj = GetAddrOfLocalVar(SrcArg);
llvm::Value *LoadOfSrc = Builder.CreateLoad(SrcObj);
for (CXXRecordDecl::base_class_const_iterator Base = ClassDecl->bases_begin();
Base != ClassDecl->bases_end(); ++Base) {
// FIXME. copy constrution of virtual base NYI
if (Base->isVirtual())
continue;
CXXRecordDecl *BaseClassDecl
= cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
EmitClassMemberwiseCopy(LoadOfThis, LoadOfSrc, ClassDecl, BaseClassDecl,
Base->getType());
}
for (CXXRecordDecl::field_iterator I = ClassDecl->field_begin(),
E = ClassDecl->field_end(); I != E; ++I) {
const FieldDecl *Field = *I;
QualType FieldType = getContext().getCanonicalType(Field->getType());
const ConstantArrayType *Array =
getContext().getAsConstantArrayType(FieldType);
if (Array)
FieldType = getContext().getBaseElementType(FieldType);
if (const RecordType *FieldClassType = FieldType->getAs<RecordType>()) {
CXXRecordDecl *FieldClassDecl
= cast<CXXRecordDecl>(FieldClassType->getDecl());
LValue LHS = EmitLValueForField(LoadOfThis, Field, 0);
LValue RHS = EmitLValueForField(LoadOfSrc, Field, 0);
if (Array) {
const llvm::Type *BasePtr = ConvertType(FieldType);
BasePtr = llvm::PointerType::getUnqual(BasePtr);
llvm::Value *DestBaseAddrPtr =
Builder.CreateBitCast(LHS.getAddress(), BasePtr);
llvm::Value *SrcBaseAddrPtr =
Builder.CreateBitCast(RHS.getAddress(), BasePtr);
EmitClassAggrMemberwiseCopy(DestBaseAddrPtr, SrcBaseAddrPtr, Array,
FieldClassDecl, FieldType);
}
else
EmitClassMemberwiseCopy(LHS.getAddress(), RHS.getAddress(),
0 /*ClassDecl*/, FieldClassDecl, FieldType);
continue;
}
// Do a built-in assignment of scalar data members.
LValue LHS = EmitLValueForFieldInitialization(LoadOfThis, Field, 0);
LValue RHS = EmitLValueForFieldInitialization(LoadOfSrc, Field, 0);
if (!hasAggregateLLVMType(Field->getType())) {
RValue RVRHS = EmitLoadOfLValue(RHS, Field->getType());
EmitStoreThroughLValue(RVRHS, LHS, Field->getType());
} else if (Field->getType()->isAnyComplexType()) {
ComplexPairTy Pair = LoadComplexFromAddr(RHS.getAddress(),
RHS.isVolatileQualified());
StoreComplexToAddr(Pair, LHS.getAddress(), LHS.isVolatileQualified());
} else {
EmitAggregateCopy(LHS.getAddress(), RHS.getAddress(), Field->getType());
}
}
InitializeVtablePtrs(ClassDecl);
}
/// SynthesizeCXXCopyAssignment - Implicitly define copy assignment operator.
/// Before the implicitly-declared copy assignment operator for a class is
/// implicitly defined, all implicitly- declared copy assignment operators for
/// its direct base classes and its nonstatic data members shall have been
/// implicitly defined. [12.8-p12]
/// The implicitly-defined copy assignment operator for class X performs
/// memberwise assignment of its subob- jects. The direct base classes of X are
/// assigned first, in the order of their declaration in
/// the base-specifier-list, and then the immediate nonstatic data members of X
/// are assigned, in the order in which they were declared in the class
/// definition.Each subobject is assigned in the manner appropriate to its type:
/// if the subobject is of class type, the copy assignment operator for the
/// class is used (as if by explicit qualification; that is, ignoring any
/// possible virtual overriding functions in more derived classes);
///
/// if the subobject is an array, each element is assigned, in the manner
/// appropriate to the element type;
///
/// if the subobject is of scalar type, the built-in assignment operator is
/// used.
void CodeGenFunction::SynthesizeCXXCopyAssignment(const FunctionArgList &Args) {
const CXXMethodDecl *CD = cast<CXXMethodDecl>(CurGD.getDecl());
const CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(CD->getDeclContext());
assert(!ClassDecl->hasUserDeclaredCopyAssignment() &&
"SynthesizeCXXCopyAssignment - copy assignment has user declaration");
FunctionArgList::const_iterator i = Args.begin();
const VarDecl *ThisArg = i->first;
llvm::Value *ThisObj = GetAddrOfLocalVar(ThisArg);
llvm::Value *LoadOfThis = Builder.CreateLoad(ThisObj, "this");
const VarDecl *SrcArg = (i+1)->first;
llvm::Value *SrcObj = GetAddrOfLocalVar(SrcArg);
llvm::Value *LoadOfSrc = Builder.CreateLoad(SrcObj);
for (CXXRecordDecl::base_class_const_iterator Base = ClassDecl->bases_begin();
Base != ClassDecl->bases_end(); ++Base) {
// FIXME. copy assignment of virtual base NYI
if (Base->isVirtual())
continue;
CXXRecordDecl *BaseClassDecl
= cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
EmitClassCopyAssignment(LoadOfThis, LoadOfSrc, ClassDecl, BaseClassDecl,
Base->getType());
}
for (CXXRecordDecl::field_iterator Field = ClassDecl->field_begin(),
FieldEnd = ClassDecl->field_end();
Field != FieldEnd; ++Field) {
QualType FieldType = getContext().getCanonicalType((*Field)->getType());
const ConstantArrayType *Array =
getContext().getAsConstantArrayType(FieldType);
if (Array)
FieldType = getContext().getBaseElementType(FieldType);
if (const RecordType *FieldClassType = FieldType->getAs<RecordType>()) {
CXXRecordDecl *FieldClassDecl
= cast<CXXRecordDecl>(FieldClassType->getDecl());
LValue LHS = EmitLValueForField(LoadOfThis, *Field, 0);
LValue RHS = EmitLValueForField(LoadOfSrc, *Field, 0);
if (Array) {
const llvm::Type *BasePtr = ConvertType(FieldType);
BasePtr = llvm::PointerType::getUnqual(BasePtr);
llvm::Value *DestBaseAddrPtr =
Builder.CreateBitCast(LHS.getAddress(), BasePtr);
llvm::Value *SrcBaseAddrPtr =
Builder.CreateBitCast(RHS.getAddress(), BasePtr);
EmitClassAggrCopyAssignment(DestBaseAddrPtr, SrcBaseAddrPtr, Array,
FieldClassDecl, FieldType);
}
else
EmitClassCopyAssignment(LHS.getAddress(), RHS.getAddress(),
0 /*ClassDecl*/, FieldClassDecl, FieldType);
continue;
}
// Do a built-in assignment of scalar data members.
LValue LHS = EmitLValueForField(LoadOfThis, *Field, 0);
LValue RHS = EmitLValueForField(LoadOfSrc, *Field, 0);
if (!hasAggregateLLVMType(Field->getType())) {
RValue RVRHS = EmitLoadOfLValue(RHS, Field->getType());
EmitStoreThroughLValue(RVRHS, LHS, Field->getType());
} else if (Field->getType()->isAnyComplexType()) {
ComplexPairTy Pair = LoadComplexFromAddr(RHS.getAddress(),
RHS.isVolatileQualified());
StoreComplexToAddr(Pair, LHS.getAddress(), LHS.isVolatileQualified());
} else {
EmitAggregateCopy(LHS.getAddress(), RHS.getAddress(), Field->getType());
}
}
// return *this;
Builder.CreateStore(LoadOfThis, ReturnValue);
}
static void EmitBaseInitializer(CodeGenFunction &CGF,
const CXXRecordDecl *ClassDecl,
CXXBaseOrMemberInitializer *BaseInit,
CXXCtorType CtorType) {
assert(BaseInit->isBaseInitializer() &&
"Must have base initializer!");
llvm::Value *ThisPtr = CGF.LoadCXXThis();
const Type *BaseType = BaseInit->getBaseClass();
CXXRecordDecl *BaseClassDecl =
cast<CXXRecordDecl>(BaseType->getAs<RecordType>()->getDecl());
// FIXME: This method of determining whether a base is virtual is ridiculous;
// it should be part of BaseInit.
bool isBaseVirtual = false;
for (CXXRecordDecl::base_class_const_iterator I = ClassDecl->vbases_begin(),
E = ClassDecl->vbases_end(); I != E; ++I)
if (I->getType()->getAs<RecordType>()->getDecl() == BaseClassDecl) {
isBaseVirtual = true;
break;
}
// The base constructor doesn't construct virtual bases.
if (CtorType == Ctor_Base && isBaseVirtual)
return;
// We can pretend to be a complete class because it only matters for
// virtual bases, and we only do virtual bases for complete ctors.
llvm::Value *V = ThisPtr;
V = CGF.GetAddressOfBaseOfCompleteClass(V, isBaseVirtual,
ClassDecl, BaseClassDecl);
CGF.EmitAggExpr(BaseInit->getInit(), V, false, false, true);
if (CGF.Exceptions && !BaseClassDecl->hasTrivialDestructor()) {
// FIXME: Is this OK for C++0x delegating constructors?
CodeGenFunction::EHCleanupBlock Cleanup(CGF);
CXXDestructorDecl *DD = BaseClassDecl->getDestructor(CGF.getContext());
CGF.EmitCXXDestructorCall(DD, Dtor_Base, V);
}
}
static void EmitMemberInitializer(CodeGenFunction &CGF,
const CXXRecordDecl *ClassDecl,
CXXBaseOrMemberInitializer *MemberInit) {
assert(MemberInit->isMemberInitializer() &&
"Must have member initializer!");
// non-static data member initializers.
FieldDecl *Field = MemberInit->getMember();
QualType FieldType = CGF.getContext().getCanonicalType(Field->getType());
llvm::Value *ThisPtr = CGF.LoadCXXThis();
LValue LHS = CGF.EmitLValueForFieldInitialization(ThisPtr, Field, 0);
// If we are initializing an anonymous union field, drill down to the field.
if (MemberInit->getAnonUnionMember()) {
Field = MemberInit->getAnonUnionMember();
LHS = CGF.EmitLValueForField(LHS.getAddress(), Field, 0);
FieldType = Field->getType();
}
// FIXME: If there's no initializer and the CXXBaseOrMemberInitializer
// was implicitly generated, we shouldn't be zeroing memory.
RValue RHS;
if (FieldType->isReferenceType()) {
RHS = CGF.EmitReferenceBindingToExpr(MemberInit->getInit(),
/*IsInitializer=*/true);
CGF.EmitStoreThroughLValue(RHS, LHS, FieldType);
} else if (FieldType->isArrayType() && !MemberInit->getInit()) {
CGF.EmitMemSetToZero(LHS.getAddress(), Field->getType());
} else if (!CGF.hasAggregateLLVMType(Field->getType())) {
RHS = RValue::get(CGF.EmitScalarExpr(MemberInit->getInit(), true));
CGF.EmitStoreThroughLValue(RHS, LHS, FieldType);
} else if (MemberInit->getInit()->getType()->isAnyComplexType()) {
CGF.EmitComplexExprIntoAddr(MemberInit->getInit(), LHS.getAddress(),
LHS.isVolatileQualified());
} else {
CGF.EmitAggExpr(MemberInit->getInit(), LHS.getAddress(),
LHS.isVolatileQualified(), false, true);
if (!CGF.Exceptions)
return;
const RecordType *RT = FieldType->getAs<RecordType>();
if (!RT)
return;
CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
if (!RD->hasTrivialDestructor()) {
// FIXME: Is this OK for C++0x delegating constructors?
CodeGenFunction::EHCleanupBlock Cleanup(CGF);
llvm::Value *ThisPtr = CGF.LoadCXXThis();
LValue LHS = CGF.EmitLValueForField(ThisPtr, Field, 0);
CXXDestructorDecl *DD = RD->getDestructor(CGF.getContext());
CGF.EmitCXXDestructorCall(DD, Dtor_Complete, LHS.getAddress());
}
}
}
/// Checks whether the given constructor is a valid subject for the
/// complete-to-base constructor delegation optimization, i.e.
/// emitting the complete constructor as a simple call to the base
/// constructor.
static bool IsConstructorDelegationValid(const CXXConstructorDecl *Ctor) {
// Currently we disable the optimization for classes with virtual
// bases because (1) the addresses of parameter variables need to be
// consistent across all initializers but (2) the delegate function
// call necessarily creates a second copy of the parameter variable.
//
// The limiting example (purely theoretical AFAIK):
// struct A { A(int &c) { c++; } };
// struct B : virtual A {
// B(int count) : A(count) { printf("%d\n", count); }
// };
// ...although even this example could in principle be emitted as a
// delegation since the address of the parameter doesn't escape.
if (Ctor->getParent()->getNumVBases()) {
// TODO: white-list trivial vbase initializers. This case wouldn't
// be subject to the restrictions below.
// TODO: white-list cases where:
// - there are no non-reference parameters to the constructor
// - the initializers don't access any non-reference parameters
// - the initializers don't take the address of non-reference
// parameters
// - etc.
// If we ever add any of the above cases, remember that:
// - function-try-blocks will always blacklist this optimization
// - we need to perform the constructor prologue and cleanup in
// EmitConstructorBody.
return false;
}
// We also disable the optimization for variadic functions because
// it's impossible to "re-pass" varargs.
if (Ctor->getType()->getAs<FunctionProtoType>()->isVariadic())
return false;
return true;
}
/// EmitConstructorBody - Emits the body of the current constructor.
void CodeGenFunction::EmitConstructorBody(FunctionArgList &Args) {
const CXXConstructorDecl *Ctor = cast<CXXConstructorDecl>(CurGD.getDecl());
CXXCtorType CtorType = CurGD.getCtorType();
// Before we go any further, try the complete->base constructor
// delegation optimization.
if (CtorType == Ctor_Complete && IsConstructorDelegationValid(Ctor)) {
EmitDelegateCXXConstructorCall(Ctor, Ctor_Base, Args);
return;
}
Stmt *Body = Ctor->getBody();
// Enter the function-try-block before the constructor prologue if
// applicable.
CXXTryStmtInfo TryInfo;
bool IsTryBody = (Body && isa<CXXTryStmt>(Body));
if (IsTryBody)
TryInfo = EnterCXXTryStmt(*cast<CXXTryStmt>(Body));
unsigned CleanupStackSize = CleanupEntries.size();
// Emit the constructor prologue, i.e. the base and member
// initializers.
EmitCtorPrologue(Ctor, CtorType);
// Emit the body of the statement.
if (IsTryBody)
EmitStmt(cast<CXXTryStmt>(Body)->getTryBlock());
else if (Body)
EmitStmt(Body);
else {
assert(Ctor->isImplicit() && "bodyless ctor not implicit");
if (!Ctor->isDefaultConstructor()) {
assert(Ctor->isCopyConstructor());
SynthesizeCXXCopyConstructor(Args);
}
}
// Emit any cleanup blocks associated with the member or base
// initializers, which includes (along the exceptional path) the
// destructors for those members and bases that were fully
// constructed.
EmitCleanupBlocks(CleanupStackSize);
if (IsTryBody)
ExitCXXTryStmt(*cast<CXXTryStmt>(Body), TryInfo);
}
/// EmitCtorPrologue - This routine generates necessary code to initialize
/// base classes and non-static data members belonging to this constructor.
void CodeGenFunction::EmitCtorPrologue(const CXXConstructorDecl *CD,
CXXCtorType CtorType) {
const CXXRecordDecl *ClassDecl = CD->getParent();
llvm::SmallVector<CXXBaseOrMemberInitializer *, 8> MemberInitializers;
// FIXME: Add vbase initialization
for (CXXConstructorDecl::init_const_iterator B = CD->init_begin(),
E = CD->init_end();
B != E; ++B) {
CXXBaseOrMemberInitializer *Member = (*B);
assert(LiveTemporaries.empty() &&
"Should not have any live temporaries at initializer start!");
if (Member->isBaseInitializer())
EmitBaseInitializer(*this, ClassDecl, Member, CtorType);
else
MemberInitializers.push_back(Member);
}
InitializeVtablePtrs(ClassDecl);
for (unsigned I = 0, E = MemberInitializers.size(); I != E; ++I) {
assert(LiveTemporaries.empty() &&
"Should not have any live temporaries at initializer start!");
EmitMemberInitializer(*this, ClassDecl, MemberInitializers[I]);
}
}
/// EmitDestructorBody - Emits the body of the current destructor.
void CodeGenFunction::EmitDestructorBody(FunctionArgList &Args) {
const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CurGD.getDecl());
CXXDtorType DtorType = CurGD.getDtorType();
Stmt *Body = Dtor->getBody();
// If the body is a function-try-block, enter the try before
// anything else --- unless we're in a deleting destructor, in which
// case we're just going to call the complete destructor and then
// call operator delete() on the way out.
CXXTryStmtInfo TryInfo;
bool isTryBody = (DtorType != Dtor_Deleting &&
Body && isa<CXXTryStmt>(Body));
if (isTryBody)
TryInfo = EnterCXXTryStmt(*cast<CXXTryStmt>(Body));
llvm::BasicBlock *DtorEpilogue = createBasicBlock("dtor.epilogue");
PushCleanupBlock(DtorEpilogue);
bool SkipBody = false; // should get jump-threaded
// If this is the deleting variant, just invoke the complete
// variant, then call the appropriate operator delete() on the way
// out.
if (DtorType == Dtor_Deleting) {
EmitCXXDestructorCall(Dtor, Dtor_Complete, LoadCXXThis());
SkipBody = true;
// If this is the complete variant, just invoke the base variant;
// the epilogue will destruct the virtual bases. But we can't do
// this optimization if the body is a function-try-block, because
// we'd introduce *two* handler blocks.
} else if (!isTryBody && DtorType == Dtor_Complete) {
EmitCXXDestructorCall(Dtor, Dtor_Base, LoadCXXThis());
SkipBody = true;
// Otherwise, we're in the base variant, so we need to ensure the
// vtable ptrs are right before emitting the body.
} else {
InitializeVtablePtrs(Dtor->getParent());
}
// Emit the body of the statement.
if (SkipBody)
(void) 0;
else if (isTryBody)
EmitStmt(cast<CXXTryStmt>(Body)->getTryBlock());
else if (Body)
EmitStmt(Body);
else {
assert(Dtor->isImplicit() && "bodyless dtor not implicit");
// nothing to do besides what's in the epilogue
}
// Jump to the cleanup block.
CleanupBlockInfo Info = PopCleanupBlock();
assert(Info.CleanupBlock == DtorEpilogue && "Block mismatch!");
EmitBlock(DtorEpilogue);
// Emit the destructor epilogue now. If this is a complete
// destructor with a function-try-block, perform the base epilogue
// as well.
if (isTryBody && DtorType == Dtor_Complete)
EmitDtorEpilogue(Dtor, Dtor_Base);
EmitDtorEpilogue(Dtor, DtorType);
// Link up the cleanup information.
if (Info.SwitchBlock)
EmitBlock(Info.SwitchBlock);
if (Info.EndBlock)
EmitBlock(Info.EndBlock);
// Exit the try if applicable.
if (isTryBody)
ExitCXXTryStmt(*cast<CXXTryStmt>(Body), TryInfo);
}
/// EmitDtorEpilogue - Emit all code that comes at the end of class's
/// destructor. This is to call destructors on members and base classes
/// in reverse order of their construction.
void CodeGenFunction::EmitDtorEpilogue(const CXXDestructorDecl *DD,
CXXDtorType DtorType) {
assert(!DD->isTrivial() &&
"Should not emit dtor epilogue for trivial dtor!");
const CXXRecordDecl *ClassDecl = DD->getParent();
// In a deleting destructor, we've already called the complete
// destructor as a subroutine, so we just have to delete the
// appropriate value.
if (DtorType == Dtor_Deleting) {
assert(DD->getOperatorDelete() &&
"operator delete missing - EmitDtorEpilogue");
EmitDeleteCall(DD->getOperatorDelete(), LoadCXXThis(),
getContext().getTagDeclType(ClassDecl));
return;
}
// For complete destructors, we've already called the base
// destructor (in GenerateBody), so we just need to destruct all the
// virtual bases.
if (DtorType == Dtor_Complete) {
// Handle virtual bases.
for (CXXRecordDecl::reverse_base_class_const_iterator I =
ClassDecl->vbases_rbegin(), E = ClassDecl->vbases_rend();
I != E; ++I) {
const CXXBaseSpecifier &Base = *I;
CXXRecordDecl *BaseClassDecl
= cast<CXXRecordDecl>(Base.getType()->getAs<RecordType>()->getDecl());
// Ignore trivial destructors.
if (BaseClassDecl->hasTrivialDestructor())
continue;
const CXXDestructorDecl *D = BaseClassDecl->getDestructor(getContext());
llvm::Value *V = GetAddressOfBaseOfCompleteClass(LoadCXXThis(),
true,
ClassDecl,
BaseClassDecl);
EmitCXXDestructorCall(D, Dtor_Base, V);
}
return;
}
assert(DtorType == Dtor_Base);
// Collect the fields.
llvm::SmallVector<const FieldDecl *, 16> FieldDecls;
for (CXXRecordDecl::field_iterator I = ClassDecl->field_begin(),
E = ClassDecl->field_end(); I != E; ++I) {
const FieldDecl *Field = *I;
QualType FieldType = getContext().getCanonicalType(Field->getType());
FieldType = getContext().getBaseElementType(FieldType);
const RecordType *RT = FieldType->getAs<RecordType>();
if (!RT)
continue;
CXXRecordDecl *FieldClassDecl = cast<CXXRecordDecl>(RT->getDecl());
if (FieldClassDecl->hasTrivialDestructor())
continue;
FieldDecls.push_back(Field);
}
// Now destroy the fields.
for (size_t i = FieldDecls.size(); i > 0; --i) {
const FieldDecl *Field = FieldDecls[i - 1];
QualType FieldType = Field->getType();
const ConstantArrayType *Array =
getContext().getAsConstantArrayType(FieldType);
if (Array)
FieldType = getContext().getBaseElementType(FieldType);
const RecordType *RT = FieldType->getAs<RecordType>();
CXXRecordDecl *FieldClassDecl = cast<CXXRecordDecl>(RT->getDecl());
llvm::Value *ThisPtr = LoadCXXThis();
LValue LHS = EmitLValueForField(ThisPtr, Field,
// FIXME: Qualifiers?
/*CVRQualifiers=*/0);
if (Array) {
const llvm::Type *BasePtr = ConvertType(FieldType);
BasePtr = llvm::PointerType::getUnqual(BasePtr);
llvm::Value *BaseAddrPtr =
Builder.CreateBitCast(LHS.getAddress(), BasePtr);
EmitCXXAggrDestructorCall(FieldClassDecl->getDestructor(getContext()),
Array, BaseAddrPtr);
} else
EmitCXXDestructorCall(FieldClassDecl->getDestructor(getContext()),
Dtor_Complete, LHS.getAddress());
}
// Destroy non-virtual bases.
for (CXXRecordDecl::reverse_base_class_const_iterator I =
ClassDecl->bases_rbegin(), E = ClassDecl->bases_rend(); I != E; ++I) {
const CXXBaseSpecifier &Base = *I;
// Ignore virtual bases.
if (Base.isVirtual())
continue;
CXXRecordDecl *BaseClassDecl
= cast<CXXRecordDecl>(Base.getType()->getAs<RecordType>()->getDecl());
// Ignore trivial destructors.
if (BaseClassDecl->hasTrivialDestructor())
continue;
const CXXDestructorDecl *D = BaseClassDecl->getDestructor(getContext());
llvm::Value *V = GetAddressOfBaseClass(LoadCXXThis(),
ClassDecl, BaseClassDecl,
/*NullCheckValue=*/false);
EmitCXXDestructorCall(D, Dtor_Base, V);
}
}
/// EmitCXXAggrConstructorCall - This routine essentially creates a (nested)
/// for-loop to call the default constructor on individual members of the
/// array.
/// 'D' is the default constructor for elements of the array, 'ArrayTy' is the
/// array type and 'ArrayPtr' points to the beginning fo the array.
/// It is assumed that all relevant checks have been made by the caller.
void
CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *D,
const ConstantArrayType *ArrayTy,
llvm::Value *ArrayPtr,
CallExpr::const_arg_iterator ArgBeg,
CallExpr::const_arg_iterator ArgEnd) {
const llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
llvm::Value * NumElements =
llvm::ConstantInt::get(SizeTy,
getContext().getConstantArrayElementCount(ArrayTy));
EmitCXXAggrConstructorCall(D, NumElements, ArrayPtr, ArgBeg, ArgEnd);
}
void
CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *D,
llvm::Value *NumElements,
llvm::Value *ArrayPtr,
CallExpr::const_arg_iterator ArgBeg,
CallExpr::const_arg_iterator ArgEnd) {
const llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
// Create a temporary for the loop index and initialize it with 0.
llvm::Value *IndexPtr = CreateTempAlloca(SizeTy, "loop.index");
llvm::Value *Zero = llvm::Constant::getNullValue(SizeTy);
Builder.CreateStore(Zero, IndexPtr);
// Start the loop with a block that tests the condition.
llvm::BasicBlock *CondBlock = createBasicBlock("for.cond");
llvm::BasicBlock *AfterFor = createBasicBlock("for.end");
EmitBlock(CondBlock);
llvm::BasicBlock *ForBody = createBasicBlock("for.body");
// Generate: if (loop-index < number-of-elements fall to the loop body,
// otherwise, go to the block after the for-loop.
llvm::Value *Counter = Builder.CreateLoad(IndexPtr);
llvm::Value *IsLess = Builder.CreateICmpULT(Counter, NumElements, "isless");
// If the condition is true, execute the body.
Builder.CreateCondBr(IsLess, ForBody, AfterFor);
EmitBlock(ForBody);
llvm::BasicBlock *ContinueBlock = createBasicBlock("for.inc");
// Inside the loop body, emit the constructor call on the array element.
Counter = Builder.CreateLoad(IndexPtr);
llvm::Value *Address = Builder.CreateInBoundsGEP(ArrayPtr, Counter,
"arrayidx");
// C++ [class.temporary]p4:
// There are two contexts in which temporaries are destroyed at a different
// point than the end of the full-expression. The first context is when a
// default constructor is called to initialize an element of an array.
// If the constructor has one or more default arguments, the destruction of
// every temporary created in a default argument expression is sequenced
// before the construction of the next array element, if any.
// Keep track of the current number of live temporaries.
unsigned OldNumLiveTemporaries = LiveTemporaries.size();
EmitCXXConstructorCall(D, Ctor_Complete, Address, ArgBeg, ArgEnd);
// Pop temporaries.
while (LiveTemporaries.size() > OldNumLiveTemporaries)
PopCXXTemporary();
EmitBlock(ContinueBlock);
// Emit the increment of the loop counter.
llvm::Value *NextVal = llvm::ConstantInt::get(SizeTy, 1);
Counter = Builder.CreateLoad(IndexPtr);
NextVal = Builder.CreateAdd(Counter, NextVal, "inc");
Builder.CreateStore(NextVal, IndexPtr);
// Finally, branch back up to the condition for the next iteration.
EmitBranch(CondBlock);
// Emit the fall-through block.
EmitBlock(AfterFor, true);
}
/// EmitCXXAggrDestructorCall - calls the default destructor on array
/// elements in reverse order of construction.
void
CodeGenFunction::EmitCXXAggrDestructorCall(const CXXDestructorDecl *D,
const ArrayType *Array,
llvm::Value *This) {
const ConstantArrayType *CA = dyn_cast<ConstantArrayType>(Array);
assert(CA && "Do we support VLA for destruction ?");
uint64_t ElementCount = getContext().getConstantArrayElementCount(CA);
const llvm::Type *SizeLTy = ConvertType(getContext().getSizeType());
llvm::Value* ElementCountPtr = llvm::ConstantInt::get(SizeLTy, ElementCount);
EmitCXXAggrDestructorCall(D, ElementCountPtr, This);
}
/// EmitCXXAggrDestructorCall - calls the default destructor on array
/// elements in reverse order of construction.
void
CodeGenFunction::EmitCXXAggrDestructorCall(const CXXDestructorDecl *D,
llvm::Value *UpperCount,
llvm::Value *This) {
const llvm::Type *SizeLTy = ConvertType(getContext().getSizeType());
llvm::Value *One = llvm::ConstantInt::get(SizeLTy, 1);
// Create a temporary for the loop index and initialize it with count of
// array elements.
llvm::Value *IndexPtr = CreateTempAlloca(SizeLTy, "loop.index");
// Store the number of elements in the index pointer.
Builder.CreateStore(UpperCount, IndexPtr);
// Start the loop with a block that tests the condition.
llvm::BasicBlock *CondBlock = createBasicBlock("for.cond");
llvm::BasicBlock *AfterFor = createBasicBlock("for.end");
EmitBlock(CondBlock);
llvm::BasicBlock *ForBody = createBasicBlock("for.body");
// Generate: if (loop-index != 0 fall to the loop body,
// otherwise, go to the block after the for-loop.
llvm::Value* zeroConstant =
llvm::Constant::getNullValue(SizeLTy);
llvm::Value *Counter = Builder.CreateLoad(IndexPtr);
llvm::Value *IsNE = Builder.CreateICmpNE(Counter, zeroConstant,
"isne");
// If the condition is true, execute the body.
Builder.CreateCondBr(IsNE, ForBody, AfterFor);
EmitBlock(ForBody);
llvm::BasicBlock *ContinueBlock = createBasicBlock("for.inc");
// Inside the loop body, emit the constructor call on the array element.
Counter = Builder.CreateLoad(IndexPtr);
Counter = Builder.CreateSub(Counter, One);
llvm::Value *Address = Builder.CreateInBoundsGEP(This, Counter, "arrayidx");
EmitCXXDestructorCall(D, Dtor_Complete, Address);
EmitBlock(ContinueBlock);
// Emit the decrement of the loop counter.
Counter = Builder.CreateLoad(IndexPtr);
Counter = Builder.CreateSub(Counter, One, "dec");
Builder.CreateStore(Counter, IndexPtr);
// Finally, branch back up to the condition for the next iteration.
EmitBranch(CondBlock);
// Emit the fall-through block.
EmitBlock(AfterFor, true);
}
/// GenerateCXXAggrDestructorHelper - Generates a helper function which when
/// invoked, calls the default destructor on array elements in reverse order of
/// construction.
llvm::Constant *
CodeGenFunction::GenerateCXXAggrDestructorHelper(const CXXDestructorDecl *D,
const ArrayType *Array,
llvm::Value *This) {
FunctionArgList Args;
ImplicitParamDecl *Dst =
ImplicitParamDecl::Create(getContext(), 0,
SourceLocation(), 0,
getContext().getPointerType(getContext().VoidTy));
Args.push_back(std::make_pair(Dst, Dst->getType()));
llvm::SmallString<16> Name;
llvm::raw_svector_ostream(Name) << "__tcf_" << (++UniqueAggrDestructorCount);
QualType R = getContext().VoidTy;
const CGFunctionInfo &FI
= CGM.getTypes().getFunctionInfo(R, Args, CC_Default, false);
const llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType(FI, false);
llvm::Function *Fn =
llvm::Function::Create(FTy, llvm::GlobalValue::InternalLinkage,
Name.str(),
&CGM.getModule());
IdentifierInfo *II = &CGM.getContext().Idents.get(Name.str());
FunctionDecl *FD = FunctionDecl::Create(getContext(),
getContext().getTranslationUnitDecl(),
SourceLocation(), II, R, 0,
FunctionDecl::Static,
false, true);
StartFunction(FD, R, Fn, Args, SourceLocation());
QualType BaseElementTy = getContext().getBaseElementType(Array);
const llvm::Type *BasePtr = ConvertType(BaseElementTy);
BasePtr = llvm::PointerType::getUnqual(BasePtr);
llvm::Value *BaseAddrPtr = Builder.CreateBitCast(This, BasePtr);
EmitCXXAggrDestructorCall(D, Array, BaseAddrPtr);
FinishFunction();
llvm::Type *Ptr8Ty = llvm::PointerType::get(llvm::Type::getInt8Ty(VMContext),
0);
llvm::Constant *m = llvm::ConstantExpr::getBitCast(Fn, Ptr8Ty);
return m;
}
void
CodeGenFunction::EmitCXXConstructorCall(const CXXConstructorDecl *D,
CXXCtorType Type,
llvm::Value *This,
CallExpr::const_arg_iterator ArgBeg,
CallExpr::const_arg_iterator ArgEnd) {
if (D->isTrivial()) {
if (ArgBeg == ArgEnd) {
// Trivial default constructor, no codegen required.
assert(D->isDefaultConstructor() &&
"trivial 0-arg ctor not a default ctor");
return;
}
assert(ArgBeg + 1 == ArgEnd && "unexpected argcount for trivial ctor");
assert(D->isCopyConstructor() && "trivial 1-arg ctor not a copy ctor");
const Expr *E = (*ArgBeg);
QualType Ty = E->getType();
llvm::Value *Src = EmitLValue(E).getAddress();
EmitAggregateCopy(This, Src, Ty);
return;
}
llvm::Value *VTT = GetVTTParameter(*this, GlobalDecl(D, Type));
llvm::Value *Callee = CGM.GetAddrOfCXXConstructor(D, Type);
EmitCXXMemberCall(D, Callee, ReturnValueSlot(), This, VTT, ArgBeg, ArgEnd);
}
void
CodeGenFunction::EmitDelegateCXXConstructorCall(const CXXConstructorDecl *Ctor,
CXXCtorType CtorType,
const FunctionArgList &Args) {
CallArgList DelegateArgs;
FunctionArgList::const_iterator I = Args.begin(), E = Args.end();
assert(I != E && "no parameters to constructor");
// this
DelegateArgs.push_back(std::make_pair(RValue::get(LoadCXXThis()),
I->second));
++I;
// vtt
if (llvm::Value *VTT = GetVTTParameter(*this, GlobalDecl(Ctor, CtorType))) {
QualType VoidPP = getContext().getPointerType(getContext().VoidPtrTy);
DelegateArgs.push_back(std::make_pair(RValue::get(VTT), VoidPP));
if (CGVtableInfo::needsVTTParameter(CurGD)) {
assert(I != E && "cannot skip vtt parameter, already done with args");
assert(I->second == VoidPP && "skipping parameter not of vtt type");
++I;
}
}
// Explicit arguments.
for (; I != E; ++I) {
const VarDecl *Param = I->first;
QualType ArgType = Param->getType(); // because we're passing it to itself
// StartFunction converted the ABI-lowered parameter(s) into a
// local alloca. We need to turn that into an r-value suitable
// for EmitCall.
llvm::Value *Local = GetAddrOfLocalVar(Param);
RValue Arg;
// For the most part, we just need to load the alloca, except:
// 1) aggregate r-values are actually pointers to temporaries, and
// 2) references to aggregates are pointers directly to the aggregate.
// I don't know why references to non-aggregates are different here.
if (ArgType->isReferenceType()) {
const ReferenceType *RefType = ArgType->getAs<ReferenceType>();
if (hasAggregateLLVMType(RefType->getPointeeType()))
Arg = RValue::getAggregate(Local);
else
// Locals which are references to scalars are represented
// with allocas holding the pointer.
Arg = RValue::get(Builder.CreateLoad(Local));
} else {
if (hasAggregateLLVMType(ArgType))
Arg = RValue::getAggregate(Local);
else
Arg = RValue::get(EmitLoadOfScalar(Local, false, ArgType));
}
DelegateArgs.push_back(std::make_pair(Arg, ArgType));
}
EmitCall(CGM.getTypes().getFunctionInfo(Ctor, CtorType),
CGM.GetAddrOfCXXConstructor(Ctor, CtorType),
ReturnValueSlot(), DelegateArgs, Ctor);
}
void CodeGenFunction::EmitCXXDestructorCall(const CXXDestructorDecl *DD,
CXXDtorType Type,
llvm::Value *This) {
llvm::Value *VTT = GetVTTParameter(*this, GlobalDecl(DD, Type));
llvm::Value *Callee = CGM.GetAddrOfCXXDestructor(DD, Type);
EmitCXXMemberCall(DD, Callee, ReturnValueSlot(), This, VTT, 0, 0);
}
llvm::Value *
CodeGenFunction::GetVirtualBaseClassOffset(llvm::Value *This,
const CXXRecordDecl *ClassDecl,
const CXXRecordDecl *BaseClassDecl) {
const llvm::Type *Int8PtrTy =
llvm::Type::getInt8Ty(VMContext)->getPointerTo();
llvm::Value *VTablePtr = Builder.CreateBitCast(This,
Int8PtrTy->getPointerTo());
VTablePtr = Builder.CreateLoad(VTablePtr, "vtable");
int64_t VBaseOffsetOffset =
CGM.getVtableInfo().getVirtualBaseOffsetOffset(ClassDecl, BaseClassDecl);
llvm::Value *VBaseOffsetPtr =
Builder.CreateConstGEP1_64(VTablePtr, VBaseOffsetOffset, "vbase.offset.ptr");
const llvm::Type *PtrDiffTy =
ConvertType(getContext().getPointerDiffType());
VBaseOffsetPtr = Builder.CreateBitCast(VBaseOffsetPtr,
PtrDiffTy->getPointerTo());
llvm::Value *VBaseOffset = Builder.CreateLoad(VBaseOffsetPtr, "vbase.offset");
return VBaseOffset;
}
void CodeGenFunction::InitializeVtablePtrs(const CXXRecordDecl *ClassDecl) {
if (!ClassDecl->isDynamicClass())
return;
llvm::Constant *Vtable = CGM.getVtableInfo().getVtable(ClassDecl);
CGVtableInfo::AddrSubMap_t& AddressPoints =
*(*CGM.getVtableInfo().AddressPoints[ClassDecl])[ClassDecl];
llvm::Value *ThisPtr = LoadCXXThis();
const ASTRecordLayout &Layout = getContext().getASTRecordLayout(ClassDecl);
// Store address points for virtual bases
for (CXXRecordDecl::base_class_const_iterator I =
ClassDecl->vbases_begin(), E = ClassDecl->vbases_end(); I != E; ++I) {
const CXXBaseSpecifier &Base = *I;
CXXRecordDecl *BaseClassDecl
= cast<CXXRecordDecl>(Base.getType()->getAs<RecordType>()->getDecl());
uint64_t Offset = Layout.getVBaseClassOffset(BaseClassDecl);
InitializeVtablePtrsRecursive(BaseClassDecl, Vtable, AddressPoints,
ThisPtr, Offset);
}
// Store address points for non-virtual bases and current class
InitializeVtablePtrsRecursive(ClassDecl, Vtable, AddressPoints, ThisPtr, 0);
}
void CodeGenFunction::InitializeVtablePtrsRecursive(
const CXXRecordDecl *ClassDecl,
llvm::Constant *Vtable,
CGVtableInfo::AddrSubMap_t& AddressPoints,
llvm::Value *ThisPtr,
uint64_t Offset) {
if (!ClassDecl->isDynamicClass())
return;
// Store address points for non-virtual bases
const ASTRecordLayout &Layout = getContext().getASTRecordLayout(ClassDecl);
for (CXXRecordDecl::base_class_const_iterator I =
ClassDecl->bases_begin(), E = ClassDecl->bases_end(); I != E; ++I) {
const CXXBaseSpecifier &Base = *I;
if (Base.isVirtual())
continue;
CXXRecordDecl *BaseClassDecl
= cast<CXXRecordDecl>(Base.getType()->getAs<RecordType>()->getDecl());
uint64_t NewOffset = Offset + Layout.getBaseClassOffset(BaseClassDecl);
InitializeVtablePtrsRecursive(BaseClassDecl, Vtable, AddressPoints,
ThisPtr, NewOffset);
}
// Compute the address point
assert(AddressPoints.count(std::make_pair(ClassDecl, Offset)) &&
"Missing address point for class");
uint64_t AddressPoint = AddressPoints[std::make_pair(ClassDecl, Offset)];
llvm::Value *VtableAddressPoint =
Builder.CreateConstInBoundsGEP2_64(Vtable, 0, AddressPoint);
// Compute the address to store the address point
const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGM.getLLVMContext());
llvm::Value *VtableField = Builder.CreateBitCast(ThisPtr, Int8PtrTy);
VtableField = Builder.CreateConstInBoundsGEP1_64(VtableField, Offset/8);
const llvm::Type *AddressPointPtrTy =
VtableAddressPoint->getType()->getPointerTo();
VtableField = Builder.CreateBitCast(VtableField, AddressPointPtrTy);
// Store address point
Builder.CreateStore(VtableAddressPoint, VtableField);
}