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clang-1/lib/CodeGen/CGClass.cpp

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//===--- 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 "CGDebugInfo.h"
#include "CodeGenFunction.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/EvaluatedExprVisitor.h"
#include "clang/AST/RecordLayout.h"
#include "clang/AST/StmtCXX.h"
using namespace clang;
using namespace CodeGen;
static uint64_t
ComputeNonVirtualBaseClassOffset(ASTContext &Context,
const CXXRecordDecl *DerivedClass,
CastExpr::path_const_iterator Start,
CastExpr::path_const_iterator End) {
uint64_t Offset = 0;
const CXXRecordDecl *RD = DerivedClass;
for (CastExpr::path_const_iterator I = Start; I != End; ++I) {
const CXXBaseSpecifier *Base = *I;
assert(!Base->isVirtual() && "Should not see virtual bases here!");
// Get the layout.
const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
// Add the offset.
Offset += Layout.getBaseClassOffsetInBits(BaseDecl);
RD = BaseDecl;
}
// FIXME: We should not use / 8 here.
return Offset / 8;
}
llvm::Constant *
CodeGenModule::GetNonVirtualBaseClassOffset(const CXXRecordDecl *ClassDecl,
CastExpr::path_const_iterator PathBegin,
CastExpr::path_const_iterator PathEnd) {
assert(PathBegin != PathEnd && "Base path should not be empty!");
uint64_t Offset =
ComputeNonVirtualBaseClassOffset(getContext(), ClassDecl,
PathBegin, PathEnd);
if (!Offset)
return 0;
const llvm::Type *PtrDiffTy =
Types.ConvertType(getContext().getPointerDiffType());
return llvm::ConstantInt::get(PtrDiffTy, Offset);
}
/// Gets the address of a direct 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::GetAddressOfDirectBaseInCompleteClass(llvm::Value *This,
const CXXRecordDecl *Derived,
const CXXRecordDecl *Base,
bool BaseIsVirtual) {
// '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 (BaseIsVirtual)
Offset = Layout.getVBaseClassOffsetInBits(Base);
else
Offset = Layout.getBaseClassOffsetInBits(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;
}
static llvm::Value *
ApplyNonVirtualAndVirtualOffset(CodeGenFunction &CGF, llvm::Value *ThisPtr,
uint64_t NonVirtual, llvm::Value *Virtual) {
const llvm::Type *PtrDiffTy =
CGF.ConvertType(CGF.getContext().getPointerDiffType());
llvm::Value *NonVirtualOffset = 0;
if (NonVirtual)
NonVirtualOffset = llvm::ConstantInt::get(PtrDiffTy, NonVirtual);
llvm::Value *BaseOffset;
if (Virtual) {
if (NonVirtualOffset)
BaseOffset = CGF.Builder.CreateAdd(Virtual, NonVirtualOffset);
else
BaseOffset = Virtual;
} else
BaseOffset = NonVirtualOffset;
// Apply the base offset.
const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGF.getLLVMContext());
ThisPtr = CGF.Builder.CreateBitCast(ThisPtr, Int8PtrTy);
ThisPtr = CGF.Builder.CreateGEP(ThisPtr, BaseOffset, "add.ptr");
return ThisPtr;
}
llvm::Value *
CodeGenFunction::GetAddressOfBaseClass(llvm::Value *Value,
const CXXRecordDecl *Derived,
CastExpr::path_const_iterator PathBegin,
CastExpr::path_const_iterator PathEnd,
bool NullCheckValue) {
assert(PathBegin != PathEnd && "Base path should not be empty!");
CastExpr::path_const_iterator Start = PathBegin;
const CXXRecordDecl *VBase = 0;
// Get the virtual base.
if ((*Start)->isVirtual()) {
VBase =
cast<CXXRecordDecl>((*Start)->getType()->getAs<RecordType>()->getDecl());
++Start;
}
uint64_t NonVirtualOffset =
ComputeNonVirtualBaseClassOffset(getContext(), VBase ? VBase : Derived,
Start, PathEnd);
// Get the base pointer type.
const llvm::Type *BasePtrTy =
ConvertType((PathEnd[-1])->getType())->getPointerTo();
if (!NonVirtualOffset && !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);
}
llvm::Value *VirtualOffset = 0;
if (VBase) {
if (Derived->hasAttr<FinalAttr>()) {
VirtualOffset = 0;
const ASTRecordLayout &Layout = getContext().getASTRecordLayout(Derived);
uint64_t VBaseOffset = Layout.getVBaseClassOffsetInBits(VBase);
NonVirtualOffset += VBaseOffset / 8;
} else
VirtualOffset = GetVirtualBaseClassOffset(Value, Derived, VBase);
}
// Apply the offsets.
Value = ApplyNonVirtualAndVirtualOffset(*this, Value, NonVirtualOffset,
VirtualOffset);
// 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 *Derived,
CastExpr::path_const_iterator PathBegin,
CastExpr::path_const_iterator PathEnd,
bool NullCheckValue) {
assert(PathBegin != PathEnd && "Base path should not be empty!");
QualType DerivedTy =
getContext().getCanonicalType(getContext().getTagDeclType(Derived));
const llvm::Type *DerivedPtrTy = ConvertType(DerivedTy)->getPointerTo();
llvm::Value *NonVirtualOffset =
CGM.GetNonVirtualBaseClassOffset(Derived, PathBegin, PathEnd);
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;
}
/// 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,
bool ForVirtualBase) {
if (!CodeGenVTables::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(!CodeGenVTables::needsVTTParameter(CGF.CurGD) &&
"doing no-op VTT offset in base dtor/ctor?");
assert(!ForVirtualBase && "Can't have same class as virtual base!");
SubVTTIndex = 0;
} else {
const ASTRecordLayout &Layout =
CGF.getContext().getASTRecordLayout(RD);
uint64_t BaseOffset = ForVirtualBase ?
Layout.getVBaseClassOffsetInBits(Base) :
Layout.getBaseClassOffsetInBits(Base);
SubVTTIndex =
CGF.CGM.getVTables().getSubVTTIndex(RD, BaseSubobject(Base, BaseOffset));
assert(SubVTTIndex != 0 && "Sub-VTT index must be greater than zero!");
}
if (CodeGenVTables::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.getVTables().GetAddrOfVTT(RD);
VTT = CGF.Builder.CreateConstInBoundsGEP2_64(VTT, 0, SubVTTIndex);
}
return VTT;
}
namespace {
/// Call the destructor for a direct base class.
struct CallBaseDtor : EHScopeStack::Cleanup {
const CXXRecordDecl *BaseClass;
bool BaseIsVirtual;
CallBaseDtor(const CXXRecordDecl *Base, bool BaseIsVirtual)
: BaseClass(Base), BaseIsVirtual(BaseIsVirtual) {}
void Emit(CodeGenFunction &CGF, bool IsForEH) {
const CXXRecordDecl *DerivedClass =
cast<CXXMethodDecl>(CGF.CurCodeDecl)->getParent();
const CXXDestructorDecl *D = BaseClass->getDestructor();
llvm::Value *Addr =
CGF.GetAddressOfDirectBaseInCompleteClass(CGF.LoadCXXThis(),
DerivedClass, BaseClass,
BaseIsVirtual);
CGF.EmitCXXDestructorCall(D, Dtor_Base, BaseIsVirtual, Addr);
}
};
/// A visitor which checks whether an initializer uses 'this' in a
/// way which requires the vtable to be properly set.
struct DynamicThisUseChecker : EvaluatedExprVisitor<DynamicThisUseChecker> {
typedef EvaluatedExprVisitor<DynamicThisUseChecker> super;
bool UsesThis;
DynamicThisUseChecker(ASTContext &C) : super(C), UsesThis(false) {}
// Black-list all explicit and implicit references to 'this'.
//
// Do we need to worry about external references to 'this' derived
// from arbitrary code? If so, then anything which runs arbitrary
// external code might potentially access the vtable.
void VisitCXXThisExpr(CXXThisExpr *E) { UsesThis = true; }
};
}
static bool BaseInitializerUsesThis(ASTContext &C, const Expr *Init) {
DynamicThisUseChecker Checker(C);
Checker.Visit(const_cast<Expr*>(Init));
return Checker.UsesThis;
}
static void EmitBaseInitializer(CodeGenFunction &CGF,
const CXXRecordDecl *ClassDecl,
CXXCtorInitializer *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());
bool isBaseVirtual = BaseInit->isBaseVirtual();
// The base constructor doesn't construct virtual bases.
if (CtorType == Ctor_Base && isBaseVirtual)
return;
// If the initializer for the base (other than the constructor
// itself) accesses 'this' in any way, we need to initialize the
// vtables.
if (BaseInitializerUsesThis(CGF.getContext(), BaseInit->getInit()))
CGF.InitializeVTablePointers(ClassDecl);
// 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 =
CGF.GetAddressOfDirectBaseInCompleteClass(ThisPtr, ClassDecl,
BaseClassDecl,
isBaseVirtual);
AggValueSlot AggSlot = AggValueSlot::forAddr(V, false, /*Lifetime*/ true);
CGF.EmitAggExpr(BaseInit->getInit(), AggSlot);
if (CGF.Exceptions && !BaseClassDecl->hasTrivialDestructor())
CGF.EHStack.pushCleanup<CallBaseDtor>(EHCleanup, BaseClassDecl,
isBaseVirtual);
}
static void EmitAggMemberInitializer(CodeGenFunction &CGF,
LValue LHS,
llvm::Value *ArrayIndexVar,
CXXCtorInitializer *MemberInit,
QualType T,
unsigned Index) {
if (Index == MemberInit->getNumArrayIndices()) {
CodeGenFunction::RunCleanupsScope Cleanups(CGF);
llvm::Value *Dest = LHS.getAddress();
if (ArrayIndexVar) {
// If we have an array index variable, load it and use it as an offset.
// Then, increment the value.
llvm::Value *ArrayIndex = CGF.Builder.CreateLoad(ArrayIndexVar);
Dest = CGF.Builder.CreateInBoundsGEP(Dest, ArrayIndex, "destaddress");
llvm::Value *Next = llvm::ConstantInt::get(ArrayIndex->getType(), 1);
Next = CGF.Builder.CreateAdd(ArrayIndex, Next, "inc");
CGF.Builder.CreateStore(Next, ArrayIndexVar);
}
AggValueSlot Slot = AggValueSlot::forAddr(Dest, LHS.isVolatileQualified(),
/*Lifetime*/ true);
CGF.EmitAggExpr(MemberInit->getInit(), Slot);
return;
}
const ConstantArrayType *Array = CGF.getContext().getAsConstantArrayType(T);
assert(Array && "Array initialization without the array type?");
llvm::Value *IndexVar
= CGF.GetAddrOfLocalVar(MemberInit->getArrayIndex(Index));
assert(IndexVar && "Array index variable not loaded");
// Initialize this index variable to zero.
llvm::Value* Zero
= llvm::Constant::getNullValue(
CGF.ConvertType(CGF.getContext().getSizeType()));
CGF.Builder.CreateStore(Zero, IndexVar);
// Start the loop with a block that tests the condition.
llvm::BasicBlock *CondBlock = CGF.createBasicBlock("for.cond");
llvm::BasicBlock *AfterFor = CGF.createBasicBlock("for.end");
CGF.EmitBlock(CondBlock);
llvm::BasicBlock *ForBody = CGF.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 = Array->getSize().getZExtValue();
llvm::Value *Counter = CGF.Builder.CreateLoad(IndexVar);
llvm::Value *NumElementsPtr =
llvm::ConstantInt::get(Counter->getType(), NumElements);
llvm::Value *IsLess = CGF.Builder.CreateICmpULT(Counter, NumElementsPtr,
"isless");
// If the condition is true, execute the body.
CGF.Builder.CreateCondBr(IsLess, ForBody, AfterFor);
CGF.EmitBlock(ForBody);
llvm::BasicBlock *ContinueBlock = CGF.createBasicBlock("for.inc");
{
CodeGenFunction::RunCleanupsScope Cleanups(CGF);
// Inside the loop body recurse to emit the inner loop or, eventually, the
// constructor call.
EmitAggMemberInitializer(CGF, LHS, ArrayIndexVar, MemberInit,
Array->getElementType(), Index + 1);
}
CGF.EmitBlock(ContinueBlock);
// Emit the increment of the loop counter.
llvm::Value *NextVal = llvm::ConstantInt::get(Counter->getType(), 1);
Counter = CGF.Builder.CreateLoad(IndexVar);
NextVal = CGF.Builder.CreateAdd(Counter, NextVal, "inc");
CGF.Builder.CreateStore(NextVal, IndexVar);
// Finally, branch back up to the condition for the next iteration.
CGF.EmitBranch(CondBlock);
// Emit the fall-through block.
CGF.EmitBlock(AfterFor, true);
}
namespace {
struct CallMemberDtor : EHScopeStack::Cleanup {
FieldDecl *Field;
CXXDestructorDecl *Dtor;
CallMemberDtor(FieldDecl *Field, CXXDestructorDecl *Dtor)
: Field(Field), Dtor(Dtor) {}
void Emit(CodeGenFunction &CGF, bool IsForEH) {
// FIXME: Is this OK for C++0x delegating constructors?
llvm::Value *ThisPtr = CGF.LoadCXXThis();
LValue LHS = CGF.EmitLValueForField(ThisPtr, Field, 0);
CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete, /*ForVirtualBase=*/false,
LHS.getAddress());
}
};
}
static void EmitMemberInitializer(CodeGenFunction &CGF,
const CXXRecordDecl *ClassDecl,
CXXCtorInitializer *MemberInit,
const CXXConstructorDecl *Constructor,
FunctionArgList &Args) {
assert(MemberInit->isAnyMemberInitializer() &&
"Must have member initializer!");
// non-static data member initializers.
FieldDecl *Field = MemberInit->getAnyMember();
QualType FieldType = CGF.getContext().getCanonicalType(Field->getType());
llvm::Value *ThisPtr = CGF.LoadCXXThis();
LValue LHS;
// If we are initializing an anonymous union field, drill down to the field.
if (MemberInit->isIndirectMemberInitializer()) {
LHS = CGF.EmitLValueForAnonRecordField(ThisPtr,
MemberInit->getIndirectMember(), 0);
FieldType = MemberInit->getIndirectMember()->getAnonField()->getType();
} else {
LHS = CGF.EmitLValueForFieldInitialization(ThisPtr, Field, 0);
}
// FIXME: If there's no initializer and the CXXCtorInitializer
// was implicitly generated, we shouldn't be zeroing memory.
RValue RHS;
if (FieldType->isReferenceType()) {
RHS = CGF.EmitReferenceBindingToExpr(MemberInit->getInit(), Field);
CGF.EmitStoreThroughLValue(RHS, LHS, FieldType);
} else if (FieldType->isArrayType() && !MemberInit->getInit()) {
CGF.EmitNullInitialization(LHS.getAddress(), Field->getType());
} else if (!CGF.hasAggregateLLVMType(Field->getType())) {
RHS = RValue::get(CGF.EmitScalarExpr(MemberInit->getInit()));
CGF.EmitStoreThroughLValue(RHS, LHS, FieldType);
} else if (MemberInit->getInit()->getType()->isAnyComplexType()) {
CGF.EmitComplexExprIntoAddr(MemberInit->getInit(), LHS.getAddress(),
LHS.isVolatileQualified());
} else {
llvm::Value *ArrayIndexVar = 0;
const ConstantArrayType *Array
= CGF.getContext().getAsConstantArrayType(FieldType);
if (Array && Constructor->isImplicit() &&
Constructor->isCopyConstructor()) {
const llvm::Type *SizeTy
= CGF.ConvertType(CGF.getContext().getSizeType());
// The LHS is a pointer to the first object we'll be constructing, as
// a flat array.
QualType BaseElementTy = CGF.getContext().getBaseElementType(Array);
const llvm::Type *BasePtr = CGF.ConvertType(BaseElementTy);
BasePtr = llvm::PointerType::getUnqual(BasePtr);
llvm::Value *BaseAddrPtr = CGF.Builder.CreateBitCast(LHS.getAddress(),
BasePtr);
LHS = CGF.MakeAddrLValue(BaseAddrPtr, BaseElementTy);
// Create an array index that will be used to walk over all of the
// objects we're constructing.
ArrayIndexVar = CGF.CreateTempAlloca(SizeTy, "object.index");
llvm::Value *Zero = llvm::Constant::getNullValue(SizeTy);
CGF.Builder.CreateStore(Zero, ArrayIndexVar);
// If we are copying an array of scalars or classes with trivial copy
// constructors, perform a single aggregate copy.
const RecordType *Record = BaseElementTy->getAs<RecordType>();
if (!Record ||
cast<CXXRecordDecl>(Record->getDecl())->hasTrivialCopyConstructor()) {
// Find the source pointer. We knows it's the last argument because
// we know we're in a copy constructor.
unsigned SrcArgIndex = Args.size() - 1;
llvm::Value *SrcPtr
= CGF.Builder.CreateLoad(
CGF.GetAddrOfLocalVar(Args[SrcArgIndex].first));
LValue Src = CGF.EmitLValueForFieldInitialization(SrcPtr, Field, 0);
// Copy the aggregate.
CGF.EmitAggregateCopy(LHS.getAddress(), Src.getAddress(), FieldType,
LHS.isVolatileQualified());
return;
}
// Emit the block variables for the array indices, if any.
for (unsigned I = 0, N = MemberInit->getNumArrayIndices(); I != N; ++I)
CGF.EmitAutoVarDecl(*MemberInit->getArrayIndex(I));
}
EmitAggMemberInitializer(CGF, LHS, ArrayIndexVar, MemberInit, FieldType, 0);
if (!CGF.Exceptions)
return;
// FIXME: If we have an array of classes w/ non-trivial destructors,
// we need to destroy in reverse order of construction along the exception
// path.
const RecordType *RT = FieldType->getAs<RecordType>();
if (!RT)
return;
CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
if (!RD->hasTrivialDestructor())
CGF.EHStack.pushCleanup<CallMemberDtor>(EHCleanup, Field,
RD->getDestructor());
}
}
/// 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)) {
if (CGDebugInfo *DI = getDebugInfo())
DI->EmitStopPoint(Builder);
EmitDelegateCXXConstructorCall(Ctor, Ctor_Base, Args);
return;
}
Stmt *Body = Ctor->getBody();
// Enter the function-try-block before the constructor prologue if
// applicable.
bool IsTryBody = (Body && isa<CXXTryStmt>(Body));
if (IsTryBody)
EnterCXXTryStmt(*cast<CXXTryStmt>(Body), true);
EHScopeStack::stable_iterator CleanupDepth = EHStack.stable_begin();
// Emit the constructor prologue, i.e. the base and member
// initializers.
EmitCtorPrologue(Ctor, CtorType, Args);
// Emit the body of the statement.
if (IsTryBody)
EmitStmt(cast<CXXTryStmt>(Body)->getTryBlock());
else if (Body)
EmitStmt(Body);
// 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.
PopCleanupBlocks(CleanupDepth);
if (IsTryBody)
ExitCXXTryStmt(*cast<CXXTryStmt>(Body), true);
}
/// 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,
FunctionArgList &Args) {
const CXXRecordDecl *ClassDecl = CD->getParent();
llvm::SmallVector<CXXCtorInitializer *, 8> MemberInitializers;
for (CXXConstructorDecl::init_const_iterator B = CD->init_begin(),
E = CD->init_end();
B != E; ++B) {
CXXCtorInitializer *Member = (*B);
if (Member->isBaseInitializer())
EmitBaseInitializer(*this, ClassDecl, Member, CtorType);
else
MemberInitializers.push_back(Member);
}
InitializeVTablePointers(ClassDecl);
for (unsigned I = 0, E = MemberInitializers.size(); I != E; ++I)
EmitMemberInitializer(*this, ClassDecl, MemberInitializers[I], CD, Args);
}
/// EmitDestructorBody - Emits the body of the current destructor.
void CodeGenFunction::EmitDestructorBody(FunctionArgList &Args) {
const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CurGD.getDecl());
CXXDtorType DtorType = CurGD.getDtorType();
// The call to operator delete in a deleting destructor happens
// outside of the function-try-block, which means it's always
// possible to delegate the destructor body to the complete
// destructor. Do so.
if (DtorType == Dtor_Deleting) {
EnterDtorCleanups(Dtor, Dtor_Deleting);
EmitCXXDestructorCall(Dtor, Dtor_Complete, /*ForVirtualBase=*/false,
LoadCXXThis());
PopCleanupBlock();
return;
}
Stmt *Body = Dtor->getBody();
// If the body is a function-try-block, enter the try before
// anything else.
bool isTryBody = (Body && isa<CXXTryStmt>(Body));
if (isTryBody)
EnterCXXTryStmt(*cast<CXXTryStmt>(Body), true);
// Enter the epilogue cleanups.
RunCleanupsScope DtorEpilogue(*this);
// 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.
switch (DtorType) {
case Dtor_Deleting: llvm_unreachable("already handled deleting case");
case Dtor_Complete:
// Enter the cleanup scopes for virtual bases.
EnterDtorCleanups(Dtor, Dtor_Complete);
if (!isTryBody) {
EmitCXXDestructorCall(Dtor, Dtor_Base, /*ForVirtualBase=*/false,
LoadCXXThis());
break;
}
// Fallthrough: act like we're in the base variant.
case Dtor_Base:
// Enter the cleanup scopes for fields and non-virtual bases.
EnterDtorCleanups(Dtor, Dtor_Base);
// Initialize the vtable pointers before entering the body.
InitializeVTablePointers(Dtor->getParent());
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
}
// -fapple-kext must inline any call to this dtor into
// the caller's body.
if (getContext().getLangOptions().AppleKext)
CurFn->addFnAttr(llvm::Attribute::AlwaysInline);
break;
}
// Jump out through the epilogue cleanups.
DtorEpilogue.ForceCleanup();
// Exit the try if applicable.
if (isTryBody)
ExitCXXTryStmt(*cast<CXXTryStmt>(Body), true);
}
namespace {
/// Call the operator delete associated with the current destructor.
struct CallDtorDelete : EHScopeStack::Cleanup {
CallDtorDelete() {}
void Emit(CodeGenFunction &CGF, bool IsForEH) {
const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CGF.CurCodeDecl);
const CXXRecordDecl *ClassDecl = Dtor->getParent();
CGF.EmitDeleteCall(Dtor->getOperatorDelete(), CGF.LoadCXXThis(),
CGF.getContext().getTagDeclType(ClassDecl));
}
};
struct CallArrayFieldDtor : EHScopeStack::Cleanup {
const FieldDecl *Field;
CallArrayFieldDtor(const FieldDecl *Field) : Field(Field) {}
void Emit(CodeGenFunction &CGF, bool IsForEH) {
QualType FieldType = Field->getType();
const ConstantArrayType *Array =
CGF.getContext().getAsConstantArrayType(FieldType);
QualType BaseType =
CGF.getContext().getBaseElementType(Array->getElementType());
const CXXRecordDecl *FieldClassDecl = BaseType->getAsCXXRecordDecl();
llvm::Value *ThisPtr = CGF.LoadCXXThis();
LValue LHS = CGF.EmitLValueForField(ThisPtr, Field,
// FIXME: Qualifiers?
/*CVRQualifiers=*/0);
const llvm::Type *BasePtr = CGF.ConvertType(BaseType)->getPointerTo();
llvm::Value *BaseAddrPtr =
CGF.Builder.CreateBitCast(LHS.getAddress(), BasePtr);
CGF.EmitCXXAggrDestructorCall(FieldClassDecl->getDestructor(),
Array, BaseAddrPtr);
}
};
struct CallFieldDtor : EHScopeStack::Cleanup {
const FieldDecl *Field;
CallFieldDtor(const FieldDecl *Field) : Field(Field) {}
void Emit(CodeGenFunction &CGF, bool IsForEH) {
const CXXRecordDecl *FieldClassDecl =
Field->getType()->getAsCXXRecordDecl();
llvm::Value *ThisPtr = CGF.LoadCXXThis();
LValue LHS = CGF.EmitLValueForField(ThisPtr, Field,
// FIXME: Qualifiers?
/*CVRQualifiers=*/0);
CGF.EmitCXXDestructorCall(FieldClassDecl->getDestructor(),
Dtor_Complete, /*ForVirtualBase=*/false,
LHS.getAddress());
}
};
}
/// 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::EnterDtorCleanups(const CXXDestructorDecl *DD,
CXXDtorType DtorType) {
assert(!DD->isTrivial() &&
"Should not emit dtor epilogue for trivial dtor!");
// The deleting-destructor phase just needs to call the appropriate
// operator delete that Sema picked up.
if (DtorType == Dtor_Deleting) {
assert(DD->getOperatorDelete() &&
"operator delete missing - EmitDtorEpilogue");
EHStack.pushCleanup<CallDtorDelete>(NormalAndEHCleanup);
return;
}
const CXXRecordDecl *ClassDecl = DD->getParent();
// The complete-destructor phase just destructs all the virtual bases.
if (DtorType == Dtor_Complete) {
// We push them in the forward order so that they'll be popped in
// the reverse order.
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());
// Ignore trivial destructors.
if (BaseClassDecl->hasTrivialDestructor())
continue;
EHStack.pushCleanup<CallBaseDtor>(NormalAndEHCleanup,
BaseClassDecl,
/*BaseIsVirtual*/ true);
}
return;
}
assert(DtorType == Dtor_Base);
// Destroy non-virtual bases.
for (CXXRecordDecl::base_class_const_iterator I =
ClassDecl->bases_begin(), E = ClassDecl->bases_end(); I != E; ++I) {
const CXXBaseSpecifier &Base = *I;
// Ignore virtual bases.
if (Base.isVirtual())
continue;
CXXRecordDecl *BaseClassDecl = Base.getType()->getAsCXXRecordDecl();
// Ignore trivial destructors.
if (BaseClassDecl->hasTrivialDestructor())
continue;
EHStack.pushCleanup<CallBaseDtor>(NormalAndEHCleanup,
BaseClassDecl,
/*BaseIsVirtual*/ false);
}
// Destroy direct 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());
const ConstantArrayType *Array =
getContext().getAsConstantArrayType(FieldType);
if (Array)
FieldType = getContext().getBaseElementType(Array->getElementType());
const RecordType *RT = FieldType->getAs<RecordType>();
if (!RT)
continue;
CXXRecordDecl *FieldClassDecl = cast<CXXRecordDecl>(RT->getDecl());
if (FieldClassDecl->hasTrivialDestructor())
continue;
if (Array)
EHStack.pushCleanup<CallArrayFieldDtor>(NormalAndEHCleanup, Field);
else
EHStack.pushCleanup<CallFieldDtor>(NormalAndEHCleanup, Field);
}
}
/// 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.
///
/// \param ZeroInitialization True if each element should be zero-initialized
/// before it is constructed.
void
CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *D,
const ConstantArrayType *ArrayTy,
llvm::Value *ArrayPtr,
CallExpr::const_arg_iterator ArgBeg,
CallExpr::const_arg_iterator ArgEnd,
bool ZeroInitialization) {
const llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
llvm::Value * NumElements =
llvm::ConstantInt::get(SizeTy,
getContext().getConstantArrayElementCount(ArrayTy));
EmitCXXAggrConstructorCall(D, NumElements, ArrayPtr, ArgBeg, ArgEnd,
ZeroInitialization);
}
void
CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *D,
llvm::Value *NumElements,
llvm::Value *ArrayPtr,
CallExpr::const_arg_iterator ArgBeg,
CallExpr::const_arg_iterator ArgEnd,
bool ZeroInitialization) {
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");
// Zero initialize the storage, if requested.
if (ZeroInitialization)
EmitNullInitialization(Address,
getContext().getTypeDeclType(D->getParent()));
// 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.
{
RunCleanupsScope Scope(*this);
EmitCXXConstructorCall(D, Ctor_Complete, /*ForVirtualBase=*/false, Address,
ArgBeg, ArgEnd);
}
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, /*ForVirtualBase=*/false, 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);
}
void
CodeGenFunction::EmitCXXConstructorCall(const CXXConstructorDecl *D,
CXXCtorType Type, bool ForVirtualBase,
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), ForVirtualBase);
llvm::Value *Callee = CGM.GetAddrOfCXXConstructor(D, Type);
EmitCXXMemberCall(D, Callee, ReturnValueSlot(), This, VTT, ArgBeg, ArgEnd);
}
void
CodeGenFunction::EmitSynthesizedCXXCopyCtorCall(const CXXConstructorDecl *D,
llvm::Value *This, llvm::Value *Src,
CallExpr::const_arg_iterator ArgBeg,
CallExpr::const_arg_iterator ArgEnd) {
if (D->isTrivial()) {
assert(ArgBeg + 1 == ArgEnd && "unexpected argcount for trivial ctor");
assert(D->isCopyConstructor() && "trivial 1-arg ctor not a copy ctor");
EmitAggregateCopy(This, Src, (*ArgBeg)->getType());
return;
}
llvm::Value *Callee = CGM.GetAddrOfCXXConstructor(D,
clang::Ctor_Complete);
assert(D->isInstance() &&
"Trying to emit a member call expr on a static method!");
const FunctionProtoType *FPT = D->getType()->getAs<FunctionProtoType>();
CallArgList Args;
// Push the this ptr.
Args.push_back(std::make_pair(RValue::get(This),
D->getThisType(getContext())));
// Push the src ptr.
QualType QT = *(FPT->arg_type_begin());
const llvm::Type *t = CGM.getTypes().ConvertType(QT);
Src = Builder.CreateBitCast(Src, t);
Args.push_back(std::make_pair(RValue::get(Src), QT));
// Skip over first argument (Src).
++ArgBeg;
CallExpr::const_arg_iterator Arg = ArgBeg;
for (FunctionProtoType::arg_type_iterator I = FPT->arg_type_begin()+1,
E = FPT->arg_type_end(); I != E; ++I, ++Arg) {
assert(Arg != ArgEnd && "Running over edge of argument list!");
QualType ArgType = *I;
Args.push_back(std::make_pair(EmitCallArg(*Arg, ArgType),
ArgType));
}
// Either we've emitted all the call args, or we have a call to a
// variadic function.
assert((Arg == ArgEnd || FPT->isVariadic()) &&
"Extra arguments in non-variadic function!");
// If we still have any arguments, emit them using the type of the argument.
for (; Arg != ArgEnd; ++Arg) {
QualType ArgType = Arg->getType();
Args.push_back(std::make_pair(EmitCallArg(*Arg, ArgType),
ArgType));
}
QualType ResultType = FPT->getResultType();
EmitCall(CGM.getTypes().getFunctionInfo(ResultType, Args,
FPT->getExtInfo()),
Callee, ReturnValueSlot(), Args, D);
}
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),
/*ForVirtualBase=*/false)) {
QualType VoidPP = getContext().getPointerType(getContext().VoidPtrTy);
DelegateArgs.push_back(std::make_pair(RValue::get(VTT), VoidPP));
if (CodeGenVTables::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
RValue Arg = EmitDelegateCallArg(Param);
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,
bool ForVirtualBase,
llvm::Value *This) {
llvm::Value *VTT = GetVTTParameter(*this, GlobalDecl(DD, Type),
ForVirtualBase);
llvm::Value *Callee = 0;
if (getContext().getLangOptions().AppleKext)
Callee = BuildAppleKextVirtualDestructorCall(DD, Type,
DD->getParent());
if (!Callee)
Callee = CGM.GetAddrOfCXXDestructor(DD, Type);
EmitCXXMemberCall(DD, Callee, ReturnValueSlot(), This, VTT, 0, 0);
}
namespace {
struct CallLocalDtor : EHScopeStack::Cleanup {
const CXXDestructorDecl *Dtor;
llvm::Value *Addr;
CallLocalDtor(const CXXDestructorDecl *D, llvm::Value *Addr)
: Dtor(D), Addr(Addr) {}
void Emit(CodeGenFunction &CGF, bool IsForEH) {
CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
/*ForVirtualBase=*/false, Addr);
}
};
}
void CodeGenFunction::PushDestructorCleanup(const CXXDestructorDecl *D,
llvm::Value *Addr) {
EHStack.pushCleanup<CallLocalDtor>(NormalAndEHCleanup, D, Addr);
}
void CodeGenFunction::PushDestructorCleanup(QualType T, llvm::Value *Addr) {
CXXRecordDecl *ClassDecl = T->getAsCXXRecordDecl();
if (!ClassDecl) return;
if (ClassDecl->hasTrivialDestructor()) return;
const CXXDestructorDecl *D = ClassDecl->getDestructor();
PushDestructorCleanup(D, Addr);
}
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 = GetVTablePtr(This, Int8PtrTy);
int64_t VBaseOffsetOffset =
CGM.getVTables().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::InitializeVTablePointer(BaseSubobject Base,
const CXXRecordDecl *NearestVBase,
uint64_t OffsetFromNearestVBase,
llvm::Constant *VTable,
const CXXRecordDecl *VTableClass) {
const CXXRecordDecl *RD = Base.getBase();
// Compute the address point.
llvm::Value *VTableAddressPoint;
// Check if we need to use a vtable from the VTT.
if (CodeGenVTables::needsVTTParameter(CurGD) &&
(RD->getNumVBases() || NearestVBase)) {
// Get the secondary vpointer index.
uint64_t VirtualPointerIndex =
CGM.getVTables().getSecondaryVirtualPointerIndex(VTableClass, Base);
/// Load the VTT.
llvm::Value *VTT = LoadCXXVTT();
if (VirtualPointerIndex)
VTT = Builder.CreateConstInBoundsGEP1_64(VTT, VirtualPointerIndex);
// And load the address point from the VTT.
VTableAddressPoint = Builder.CreateLoad(VTT);
} else {
uint64_t AddressPoint = CGM.getVTables().getAddressPoint(Base, VTableClass);
VTableAddressPoint =
Builder.CreateConstInBoundsGEP2_64(VTable, 0, AddressPoint);
}
// Compute where to store the address point.
llvm::Value *VirtualOffset = 0;
uint64_t NonVirtualOffset = 0;
if (CodeGenVTables::needsVTTParameter(CurGD) && NearestVBase) {
// We need to use the virtual base offset offset because the virtual base
// might have a different offset in the most derived class.
VirtualOffset = GetVirtualBaseClassOffset(LoadCXXThis(), VTableClass,
NearestVBase);
NonVirtualOffset = OffsetFromNearestVBase / 8;
} else {
// We can just use the base offset in the complete class.
NonVirtualOffset = Base.getBaseOffset() / 8;
}
// Apply the offsets.
llvm::Value *VTableField = LoadCXXThis();
if (NonVirtualOffset || VirtualOffset)
VTableField = ApplyNonVirtualAndVirtualOffset(*this, VTableField,
NonVirtualOffset,
VirtualOffset);
// Finally, store the address point.
const llvm::Type *AddressPointPtrTy =
VTableAddressPoint->getType()->getPointerTo();
VTableField = Builder.CreateBitCast(VTableField, AddressPointPtrTy);
Builder.CreateStore(VTableAddressPoint, VTableField);
}
void
CodeGenFunction::InitializeVTablePointers(BaseSubobject Base,
const CXXRecordDecl *NearestVBase,
uint64_t OffsetFromNearestVBase,
bool BaseIsNonVirtualPrimaryBase,
llvm::Constant *VTable,
const CXXRecordDecl *VTableClass,
VisitedVirtualBasesSetTy& VBases) {
// If this base is a non-virtual primary base the address point has already
// been set.
if (!BaseIsNonVirtualPrimaryBase) {
// Initialize the vtable pointer for this base.
InitializeVTablePointer(Base, NearestVBase, OffsetFromNearestVBase,
VTable, VTableClass);
}
const CXXRecordDecl *RD = Base.getBase();
// Traverse bases.
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
CXXRecordDecl *BaseDecl
= cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
// Ignore classes without a vtable.
if (!BaseDecl->isDynamicClass())
continue;
uint64_t BaseOffset;
uint64_t BaseOffsetFromNearestVBase;
bool BaseDeclIsNonVirtualPrimaryBase;
if (I->isVirtual()) {
// Check if we've visited this virtual base before.
if (!VBases.insert(BaseDecl))
continue;
const ASTRecordLayout &Layout =
getContext().getASTRecordLayout(VTableClass);
BaseOffset = Layout.getVBaseClassOffsetInBits(BaseDecl);
BaseOffsetFromNearestVBase = 0;
BaseDeclIsNonVirtualPrimaryBase = false;
} else {
const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
BaseOffset =
Base.getBaseOffset() + Layout.getBaseClassOffsetInBits(BaseDecl);
BaseOffsetFromNearestVBase =
OffsetFromNearestVBase + Layout.getBaseClassOffsetInBits(BaseDecl);
BaseDeclIsNonVirtualPrimaryBase = Layout.getPrimaryBase() == BaseDecl;
}
InitializeVTablePointers(BaseSubobject(BaseDecl, BaseOffset),
I->isVirtual() ? BaseDecl : NearestVBase,
BaseOffsetFromNearestVBase,
BaseDeclIsNonVirtualPrimaryBase,
VTable, VTableClass, VBases);
}
}
void CodeGenFunction::InitializeVTablePointers(const CXXRecordDecl *RD) {
// Ignore classes without a vtable.
if (!RD->isDynamicClass())
return;
// Get the VTable.
llvm::Constant *VTable = CGM.getVTables().GetAddrOfVTable(RD);
// Initialize the vtable pointers for this class and all of its bases.
VisitedVirtualBasesSetTy VBases;
InitializeVTablePointers(BaseSubobject(RD, 0), /*NearestVBase=*/0,
/*OffsetFromNearestVBase=*/0,
/*BaseIsNonVirtualPrimaryBase=*/false,
VTable, RD, VBases);
}
llvm::Value *CodeGenFunction::GetVTablePtr(llvm::Value *This,
const llvm::Type *Ty) {
llvm::Value *VTablePtrSrc = Builder.CreateBitCast(This, Ty->getPointerTo());
return Builder.CreateLoad(VTablePtrSrc, "vtable");
}
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