| //===--- 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 CXXRecordDecl *DerivedClass, |
| CXXBaseSpecifierArray::iterator Start, |
| CXXBaseSpecifierArray::iterator End) { |
| uint64_t Offset = 0; |
| |
| const CXXRecordDecl *RD = DerivedClass; |
| |
| for (CXXBaseSpecifierArray::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.getBaseClassOffset(BaseDecl); |
| |
| RD = BaseDecl; |
| } |
| |
| // FIXME: We should not use / 8 here. |
| return Offset / 8; |
| } |
| |
| llvm::Constant * |
| CodeGenModule::GetNonVirtualBaseClassOffset(const CXXRecordDecl *ClassDecl, |
| const CXXBaseSpecifierArray &BasePath) { |
| assert(!BasePath.empty() && "Base path should not be empty!"); |
| |
| uint64_t Offset = |
| ComputeNonVirtualBaseClassOffset(getContext(), ClassDecl, |
| BasePath.begin(), BasePath.end()); |
| 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.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; |
| } |
| |
| 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, |
| const CXXBaseSpecifierArray &BasePath, |
| bool NullCheckValue) { |
| assert(!BasePath.empty() && "Base path should not be empty!"); |
| |
| CXXBaseSpecifierArray::iterator Start = BasePath.begin(); |
| 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, BasePath.end()); |
| |
| // Get the base pointer type. |
| const llvm::Type *BasePtrTy = |
| ConvertType((BasePath.end()[-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) |
| 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, |
| const CXXBaseSpecifierArray &BasePath, |
| bool NullCheckValue) { |
| assert(!BasePath.empty() && "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, BasePath); |
| |
| 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.getVBaseClassOffset(Base) : Layout.getBaseClassOffset(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().getVTT(RD); |
| VTT = CGF.Builder.CreateConstInBoundsGEP2_64(VTT, 0, SubVTTIndex); |
| } |
| |
| return VTT; |
| } |
| |
| 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()); |
| |
| bool isBaseVirtual = BaseInit->isBaseVirtual(); |
| |
| // 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 = |
| CGF.GetAddressOfDirectBaseInCompleteClass(ThisPtr, ClassDecl, |
| BaseClassDecl, |
| BaseInit->isBaseVirtual()); |
| |
| 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, isBaseVirtual, V); |
| } |
| } |
| |
| static void EmitAggMemberInitializer(CodeGenFunction &CGF, |
| LValue LHS, |
| llvm::Value *ArrayIndexVar, |
| CXXBaseOrMemberInitializer *MemberInit, |
| QualType T, |
| unsigned Index) { |
| if (Index == MemberInit->getNumArrayIndices()) { |
| CodeGenFunction::CleanupScope 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); |
| } |
| |
| CGF.EmitAggExpr(MemberInit->getInit(), Dest, |
| LHS.isVolatileQualified(), |
| /*IgnoreResult*/ false, |
| /*IsInitializer*/ true); |
| |
| 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::CleanupScope 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); |
| } |
| |
| static void EmitMemberInitializer(CodeGenFunction &CGF, |
| const CXXRecordDecl *ClassDecl, |
| CXXBaseOrMemberInitializer *MemberInit, |
| const CXXConstructorDecl *Constructor, |
| FunctionArgList &Args) { |
| 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; |
| |
| // If we are initializing an anonymous union field, drill down to the field. |
| if (MemberInit->getAnonUnionMember()) { |
| Field = MemberInit->getAnonUnionMember(); |
| LHS = CGF.EmitLValueForAnonRecordField(ThisPtr, Field, 0); |
| FieldType = Field->getType(); |
| } else { |
| LHS = CGF.EmitLValueForFieldInitialization(ThisPtr, Field, 0); |
| } |
| |
| // 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(), 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 = LValue::MakeAddr(BaseAddrPtr, CGF.MakeQualifiers(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.EmitLocalBlockVarDecl(*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()) { |
| // 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, /*ForVirtualBase=*/false, |
| 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, 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. |
| 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, |
| FunctionArgList &Args) { |
| const CXXRecordDecl *ClassDecl = CD->getParent(); |
| |
| llvm::SmallVector<CXXBaseOrMemberInitializer *, 8> MemberInitializers; |
| |
| 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); |
| } |
| |
| InitializeVTablePointers(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], 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(); |
| |
| 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, /*ForVirtualBase=*/false, |
| 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, /*ForVirtualBase=*/false, |
| 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 { |
| InitializeVTablePointers(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 = |
| GetAddressOfDirectBaseInCompleteClass(LoadCXXThis(), |
| ClassDecl, BaseClassDecl, |
| /*BaseIsVirtual=*/true); |
| EmitCXXDestructorCall(D, Dtor_Base, /*ForVirtualBase=*/true, 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, /*ForVirtualBase=*/false, |
| 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 = |
| GetAddressOfDirectBaseInCompleteClass(LoadCXXThis(), ClassDecl, |
| BaseClassDecl, |
| /*BaseIsVirtual=*/false); |
| |
| EmitCXXDestructorCall(D, Dtor_Base, /*ForVirtualBase=*/false, 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. |
| { |
| CXXTemporariesCleanupScope 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::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 = 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.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.getVBaseClassOffset(BaseDecl); |
| BaseOffsetFromNearestVBase = 0; |
| BaseDeclIsNonVirtualPrimaryBase = false; |
| } else { |
| const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD); |
| |
| BaseOffset = Base.getBaseOffset() + Layout.getBaseClassOffset(BaseDecl); |
| BaseOffsetFromNearestVBase = |
| OffsetFromNearestVBase + Layout.getBaseClassOffset(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); |
| } |