| //===--- 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 "CGBlocks.h" |
| #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" |
| #include "clang/Frontend/CodeGenOptions.h" |
| |
| using namespace clang; |
| using namespace CodeGen; |
| |
| static CharUnits |
| ComputeNonVirtualBaseClassOffset(ASTContext &Context, |
| const CXXRecordDecl *DerivedClass, |
| CastExpr::path_const_iterator Start, |
| CastExpr::path_const_iterator End) { |
| CharUnits Offset = CharUnits::Zero(); |
| |
| 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.getBaseClassOffset(BaseDecl); |
| |
| RD = BaseDecl; |
| } |
| |
| return Offset; |
| } |
| |
| 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!"); |
| |
| CharUnits Offset = |
| ComputeNonVirtualBaseClassOffset(getContext(), ClassDecl, |
| PathBegin, PathEnd); |
| if (Offset.isZero()) |
| return 0; |
| |
| llvm::Type *PtrDiffTy = |
| Types.ConvertType(getContext().getPointerDiffType()); |
| |
| return llvm::ConstantInt::get(PtrDiffTy, Offset.getQuantity()); |
| } |
| |
| /// 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. |
| CharUnits 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.isPositive()) { |
| V = Builder.CreateBitCast(V, Int8PtrTy); |
| V = Builder.CreateConstInBoundsGEP1_64(V, Offset.getQuantity()); |
| } |
| V = Builder.CreateBitCast(V, ConvertType(Base)->getPointerTo()); |
| |
| return V; |
| } |
| |
| static llvm::Value * |
| ApplyNonVirtualAndVirtualOffset(CodeGenFunction &CGF, llvm::Value *ptr, |
| CharUnits nonVirtualOffset, |
| llvm::Value *virtualOffset) { |
| // Assert that we have something to do. |
| assert(!nonVirtualOffset.isZero() || virtualOffset != 0); |
| |
| // Compute the offset from the static and dynamic components. |
| llvm::Value *baseOffset; |
| if (!nonVirtualOffset.isZero()) { |
| baseOffset = llvm::ConstantInt::get(CGF.PtrDiffTy, |
| nonVirtualOffset.getQuantity()); |
| if (virtualOffset) { |
| baseOffset = CGF.Builder.CreateAdd(virtualOffset, baseOffset); |
| } |
| } else { |
| baseOffset = virtualOffset; |
| } |
| |
| // Apply the base offset. |
| ptr = CGF.Builder.CreateBitCast(ptr, CGF.Int8PtrTy); |
| ptr = CGF.Builder.CreateInBoundsGEP(ptr, baseOffset, "add.ptr"); |
| return ptr; |
| } |
| |
| 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; |
| |
| // Sema has done some convenient canonicalization here: if the |
| // access path involved any virtual steps, the conversion path will |
| // *start* with a step down to the correct virtual base subobject, |
| // and hence will not require any further steps. |
| if ((*Start)->isVirtual()) { |
| VBase = |
| cast<CXXRecordDecl>((*Start)->getType()->getAs<RecordType>()->getDecl()); |
| ++Start; |
| } |
| |
| // Compute the static offset of the ultimate destination within its |
| // allocating subobject (the virtual base, if there is one, or else |
| // the "complete" object that we see). |
| CharUnits NonVirtualOffset = |
| ComputeNonVirtualBaseClassOffset(getContext(), VBase ? VBase : Derived, |
| Start, PathEnd); |
| |
| // If there's a virtual step, we can sometimes "devirtualize" it. |
| // For now, that's limited to when the derived type is final. |
| // TODO: "devirtualize" this for accesses to known-complete objects. |
| if (VBase && Derived->hasAttr<FinalAttr>()) { |
| const ASTRecordLayout &layout = getContext().getASTRecordLayout(Derived); |
| CharUnits vBaseOffset = layout.getVBaseClassOffset(VBase); |
| NonVirtualOffset += vBaseOffset; |
| VBase = 0; // we no longer have a virtual step |
| } |
| |
| // Get the base pointer type. |
| llvm::Type *BasePtrTy = |
| ConvertType((PathEnd[-1])->getType())->getPointerTo(); |
| |
| // If the static offset is zero and we don't have a virtual step, |
| // just do a bitcast; null checks are unnecessary. |
| if (NonVirtualOffset.isZero() && !VBase) { |
| return Builder.CreateBitCast(Value, BasePtrTy); |
| } |
| |
| llvm::BasicBlock *origBB = 0; |
| llvm::BasicBlock *endBB = 0; |
| |
| // Skip over the offset (and the vtable load) if we're supposed to |
| // null-check the pointer. |
| if (NullCheckValue) { |
| origBB = Builder.GetInsertBlock(); |
| llvm::BasicBlock *notNullBB = createBasicBlock("cast.notnull"); |
| endBB = createBasicBlock("cast.end"); |
| |
| llvm::Value *isNull = Builder.CreateIsNull(Value); |
| Builder.CreateCondBr(isNull, endBB, notNullBB); |
| EmitBlock(notNullBB); |
| } |
| |
| // Compute the virtual offset. |
| llvm::Value *VirtualOffset = 0; |
| if (VBase) { |
| VirtualOffset = GetVirtualBaseClassOffset(Value, Derived, VBase); |
| } |
| |
| // Apply both offsets. |
| Value = ApplyNonVirtualAndVirtualOffset(*this, Value, |
| NonVirtualOffset, |
| VirtualOffset); |
| |
| // Cast to the destination type. |
| Value = Builder.CreateBitCast(Value, BasePtrTy); |
| |
| // Build a phi if we needed a null check. |
| if (NullCheckValue) { |
| llvm::BasicBlock *notNullBB = Builder.GetInsertBlock(); |
| Builder.CreateBr(endBB); |
| EmitBlock(endBB); |
| |
| llvm::PHINode *PHI = Builder.CreatePHI(BasePtrTy, 2, "cast.result"); |
| PHI->addIncoming(Value, notNullBB); |
| PHI->addIncoming(llvm::Constant::getNullValue(BasePtrTy), origBB); |
| 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)); |
| 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.CreateIsNull(Value); |
| Builder.CreateCondBr(IsNull, CastNull, CastNotNull); |
| EmitBlock(CastNotNull); |
| } |
| |
| // Apply the offset. |
| Value = Builder.CreateBitCast(Value, Int8PtrTy); |
| Value = Builder.CreateGEP(Value, Builder.CreateNeg(NonVirtualOffset), |
| "sub.ptr"); |
| |
| // 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(), 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, |
| bool Delegating) { |
| 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 (Delegating) { |
| // If this is a delegating constructor call, just load the VTT. |
| return CGF.LoadCXXVTT(); |
| } else if (RD == Base) { |
| // If the record matches the base, this is the complete ctor/dtor |
| // variant calling the base variant in a class with virtual bases. |
| 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); |
| CharUnits 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().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, Flags flags) { |
| 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, |
| /*Delegating=*/false, 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); |
| CharUnits Alignment = CGF.getContext().getTypeAlignInChars(BaseType); |
| AggValueSlot AggSlot = |
| AggValueSlot::forAddr(V, Alignment, Qualifiers(), |
| AggValueSlot::IsDestructed, |
| AggValueSlot::DoesNotNeedGCBarriers, |
| AggValueSlot::IsNotAliased); |
| |
| CGF.EmitAggExpr(BaseInit->getInit(), AggSlot); |
| |
| if (CGF.CGM.getLangOpts().Exceptions && |
| !BaseClassDecl->hasTrivialDestructor()) |
| CGF.EHStack.pushCleanup<CallBaseDtor>(EHCleanup, BaseClassDecl, |
| isBaseVirtual); |
| } |
| |
| static void EmitAggMemberInitializer(CodeGenFunction &CGF, |
| LValue LHS, |
| Expr *Init, |
| llvm::Value *ArrayIndexVar, |
| QualType T, |
| ArrayRef<VarDecl *> ArrayIndexes, |
| unsigned Index) { |
| if (Index == ArrayIndexes.size()) { |
| LValue LV = LHS; |
| { // Scope for Cleanups. |
| CodeGenFunction::RunCleanupsScope Cleanups(CGF); |
| |
| if (ArrayIndexVar) { |
| // If we have an array index variable, load it and use it as an offset. |
| // Then, increment the value. |
| llvm::Value *Dest = LHS.getAddress(); |
| 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); |
| |
| // Update the LValue. |
| LV.setAddress(Dest); |
| CharUnits Align = CGF.getContext().getTypeAlignInChars(T); |
| LV.setAlignment(std::min(Align, LV.getAlignment())); |
| } |
| |
| if (!CGF.hasAggregateLLVMType(T)) { |
| CGF.EmitScalarInit(Init, /*decl*/ 0, LV, false); |
| } else if (T->isAnyComplexType()) { |
| CGF.EmitComplexExprIntoAddr(Init, LV.getAddress(), |
| LV.isVolatileQualified()); |
| } else { |
| AggValueSlot Slot = |
| AggValueSlot::forLValue(LV, |
| AggValueSlot::IsDestructed, |
| AggValueSlot::DoesNotNeedGCBarriers, |
| AggValueSlot::IsNotAliased); |
| |
| CGF.EmitAggExpr(Init, Slot); |
| } |
| } |
| |
| // Now, outside of the initializer cleanup scope, destroy the backing array |
| // for a std::initializer_list member. |
| CGF.MaybeEmitStdInitializerListCleanup(LV.getAddress(), Init); |
| |
| return; |
| } |
| |
| const ConstantArrayType *Array = CGF.getContext().getAsConstantArrayType(T); |
| assert(Array && "Array initialization without the array type?"); |
| llvm::Value *IndexVar |
| = CGF.GetAddrOfLocalVar(ArrayIndexes[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, Init, ArrayIndexVar, |
| Array->getElementType(), ArrayIndexes, 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, |
| CXXCtorInitializer *MemberInit, |
| const CXXConstructorDecl *Constructor, |
| FunctionArgList &Args) { |
| assert(MemberInit->isAnyMemberInitializer() && |
| "Must have member initializer!"); |
| assert(MemberInit->getInit() && "Must have initializer!"); |
| |
| // non-static data member initializers. |
| FieldDecl *Field = MemberInit->getAnyMember(); |
| QualType FieldType = Field->getType(); |
| |
| llvm::Value *ThisPtr = CGF.LoadCXXThis(); |
| QualType RecordTy = CGF.getContext().getTypeDeclType(ClassDecl); |
| LValue LHS = CGF.MakeNaturalAlignAddrLValue(ThisPtr, RecordTy); |
| |
| if (MemberInit->isIndirectMemberInitializer()) { |
| // If we are initializing an anonymous union field, drill down to |
| // the field. |
| IndirectFieldDecl *IndirectField = MemberInit->getIndirectMember(); |
| IndirectFieldDecl::chain_iterator I = IndirectField->chain_begin(), |
| IEnd = IndirectField->chain_end(); |
| for ( ; I != IEnd; ++I) |
| LHS = CGF.EmitLValueForFieldInitialization(LHS, cast<FieldDecl>(*I)); |
| FieldType = MemberInit->getIndirectMember()->getAnonField()->getType(); |
| } else { |
| LHS = CGF.EmitLValueForFieldInitialization(LHS, Field); |
| } |
| |
| // Special case: if we are in a copy or move constructor, and we are copying |
| // an array of PODs or classes with trivial copy constructors, ignore the |
| // AST and perform the copy we know is equivalent. |
| // FIXME: This is hacky at best... if we had a bit more explicit information |
| // in the AST, we could generalize it more easily. |
| const ConstantArrayType *Array |
| = CGF.getContext().getAsConstantArrayType(FieldType); |
| if (Array && Constructor->isImplicitlyDefined() && |
| Constructor->isCopyOrMoveConstructor()) { |
| QualType BaseElementTy = CGF.getContext().getBaseElementType(Array); |
| CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(MemberInit->getInit()); |
| if (BaseElementTy.isPODType(CGF.getContext()) || |
| (CE && CE->getConstructor()->isTrivial())) { |
| // Find the source pointer. We know it's the last argument because |
| // we know we're in an implicit copy constructor. |
| unsigned SrcArgIndex = Args.size() - 1; |
| llvm::Value *SrcPtr |
| = CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(Args[SrcArgIndex])); |
| LValue ThisRHSLV = CGF.MakeNaturalAlignAddrLValue(SrcPtr, RecordTy); |
| LValue Src = CGF.EmitLValueForFieldInitialization(ThisRHSLV, Field); |
| |
| // Copy the aggregate. |
| CGF.EmitAggregateCopy(LHS.getAddress(), Src.getAddress(), FieldType, |
| LHS.isVolatileQualified()); |
| return; |
| } |
| } |
| |
| ArrayRef<VarDecl *> ArrayIndexes; |
| if (MemberInit->getNumArrayIndices()) |
| ArrayIndexes = MemberInit->getArrayIndexes(); |
| CGF.EmitInitializerForField(Field, LHS, MemberInit->getInit(), ArrayIndexes); |
| } |
| |
| void CodeGenFunction::EmitInitializerForField(FieldDecl *Field, |
| LValue LHS, Expr *Init, |
| ArrayRef<VarDecl *> ArrayIndexes) { |
| QualType FieldType = Field->getType(); |
| if (!hasAggregateLLVMType(FieldType)) { |
| if (LHS.isSimple()) { |
| EmitExprAsInit(Init, Field, LHS, false); |
| } else { |
| RValue RHS = RValue::get(EmitScalarExpr(Init)); |
| EmitStoreThroughLValue(RHS, LHS); |
| } |
| } else if (FieldType->isAnyComplexType()) { |
| EmitComplexExprIntoAddr(Init, LHS.getAddress(), LHS.isVolatileQualified()); |
| } else { |
| llvm::Value *ArrayIndexVar = 0; |
| if (ArrayIndexes.size()) { |
| llvm::Type *SizeTy = ConvertType(getContext().getSizeType()); |
| |
| // The LHS is a pointer to the first object we'll be constructing, as |
| // a flat array. |
| QualType BaseElementTy = getContext().getBaseElementType(FieldType); |
| llvm::Type *BasePtr = ConvertType(BaseElementTy); |
| BasePtr = llvm::PointerType::getUnqual(BasePtr); |
| llvm::Value *BaseAddrPtr = Builder.CreateBitCast(LHS.getAddress(), |
| BasePtr); |
| LHS = MakeAddrLValue(BaseAddrPtr, BaseElementTy); |
| |
| // Create an array index that will be used to walk over all of the |
| // objects we're constructing. |
| ArrayIndexVar = CreateTempAlloca(SizeTy, "object.index"); |
| llvm::Value *Zero = llvm::Constant::getNullValue(SizeTy); |
| Builder.CreateStore(Zero, ArrayIndexVar); |
| |
| |
| // Emit the block variables for the array indices, if any. |
| for (unsigned I = 0, N = ArrayIndexes.size(); I != N; ++I) |
| EmitAutoVarDecl(*ArrayIndexes[I]); |
| } |
| |
| EmitAggMemberInitializer(*this, LHS, Init, ArrayIndexVar, FieldType, |
| ArrayIndexes, 0); |
| } |
| |
| // Ensure that we destroy this object if an exception is thrown |
| // later in the constructor. |
| QualType::DestructionKind dtorKind = FieldType.isDestructedType(); |
| if (needsEHCleanup(dtorKind)) |
| pushEHDestroy(dtorKind, LHS.getAddress(), FieldType); |
| } |
| |
| /// 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; |
| |
| // FIXME: Decide if we can do a delegation of a delegating constructor. |
| if (Ctor->isDelegatingConstructor()) |
| 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) && |
| CGM.getContext().getTargetInfo().getCXXABI().hasConstructorVariants()) { |
| if (CGDebugInfo *DI = getDebugInfo()) |
| DI->EmitLocation(Builder, Ctor->getLocEnd()); |
| 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(); |
| |
| // TODO: in restricted cases, we can emit the vbase initializers of |
| // a complete ctor and then delegate to the base ctor. |
| |
| // 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) { |
| if (CD->isDelegatingConstructor()) |
| return EmitDelegatingCXXConstructorCall(CD, Args); |
| |
| const CXXRecordDecl *ClassDecl = CD->getParent(); |
| |
| 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 { |
| assert(Member->isAnyMemberInitializer() && |
| "Delegating initializer on non-delegating constructor"); |
| MemberInitializers.push_back(Member); |
| } |
| } |
| |
| InitializeVTablePointers(ClassDecl); |
| |
| for (unsigned I = 0, E = MemberInitializers.size(); I != E; ++I) |
| EmitMemberInitializer(*this, ClassDecl, MemberInitializers[I], CD, Args); |
| } |
| |
| static bool |
| FieldHasTrivialDestructorBody(ASTContext &Context, const FieldDecl *Field); |
| |
| static bool |
| HasTrivialDestructorBody(ASTContext &Context, |
| const CXXRecordDecl *BaseClassDecl, |
| const CXXRecordDecl *MostDerivedClassDecl) |
| { |
| // If the destructor is trivial we don't have to check anything else. |
| if (BaseClassDecl->hasTrivialDestructor()) |
| return true; |
| |
| if (!BaseClassDecl->getDestructor()->hasTrivialBody()) |
| return false; |
| |
| // Check fields. |
| for (CXXRecordDecl::field_iterator I = BaseClassDecl->field_begin(), |
| E = BaseClassDecl->field_end(); I != E; ++I) { |
| const FieldDecl *Field = *I; |
| |
| if (!FieldHasTrivialDestructorBody(Context, Field)) |
| return false; |
| } |
| |
| // Check non-virtual bases. |
| for (CXXRecordDecl::base_class_const_iterator I = |
| BaseClassDecl->bases_begin(), E = BaseClassDecl->bases_end(); |
| I != E; ++I) { |
| if (I->isVirtual()) |
| continue; |
| |
| const CXXRecordDecl *NonVirtualBase = |
| cast<CXXRecordDecl>(I->getType()->castAs<RecordType>()->getDecl()); |
| if (!HasTrivialDestructorBody(Context, NonVirtualBase, |
| MostDerivedClassDecl)) |
| return false; |
| } |
| |
| if (BaseClassDecl == MostDerivedClassDecl) { |
| // Check virtual bases. |
| for (CXXRecordDecl::base_class_const_iterator I = |
| BaseClassDecl->vbases_begin(), E = BaseClassDecl->vbases_end(); |
| I != E; ++I) { |
| const CXXRecordDecl *VirtualBase = |
| cast<CXXRecordDecl>(I->getType()->castAs<RecordType>()->getDecl()); |
| if (!HasTrivialDestructorBody(Context, VirtualBase, |
| MostDerivedClassDecl)) |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| static bool |
| FieldHasTrivialDestructorBody(ASTContext &Context, |
| const FieldDecl *Field) |
| { |
| QualType FieldBaseElementType = Context.getBaseElementType(Field->getType()); |
| |
| const RecordType *RT = FieldBaseElementType->getAs<RecordType>(); |
| if (!RT) |
| return true; |
| |
| CXXRecordDecl *FieldClassDecl = cast<CXXRecordDecl>(RT->getDecl()); |
| return HasTrivialDestructorBody(Context, FieldClassDecl, FieldClassDecl); |
| } |
| |
| /// CanSkipVTablePointerInitialization - Check whether we need to initialize |
| /// any vtable pointers before calling this destructor. |
| static bool CanSkipVTablePointerInitialization(ASTContext &Context, |
| const CXXDestructorDecl *Dtor) { |
| if (!Dtor->hasTrivialBody()) |
| return false; |
| |
| // Check the fields. |
| const CXXRecordDecl *ClassDecl = Dtor->getParent(); |
| for (CXXRecordDecl::field_iterator I = ClassDecl->field_begin(), |
| E = ClassDecl->field_end(); I != E; ++I) { |
| const FieldDecl *Field = *I; |
| |
| if (!FieldHasTrivialDestructorBody(Context, Field)) |
| return false; |
| } |
| |
| return true; |
| } |
| |
| /// 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, |
| /*Delegating=*/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 && |
| CGM.getContext().getTargetInfo().getCXXABI().hasDestructorVariants()) { |
| EmitCXXDestructorCall(Dtor, Dtor_Base, /*ForVirtualBase=*/false, |
| /*Delegating=*/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. |
| if (!CanSkipVTablePointerInitialization(getContext(), Dtor)) |
| 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 (getLangOpts().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, Flags flags) { |
| const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CGF.CurCodeDecl); |
| const CXXRecordDecl *ClassDecl = Dtor->getParent(); |
| CGF.EmitDeleteCall(Dtor->getOperatorDelete(), CGF.LoadCXXThis(), |
| CGF.getContext().getTagDeclType(ClassDecl)); |
| } |
| }; |
| |
| struct CallDtorDeleteConditional : EHScopeStack::Cleanup { |
| llvm::Value *ShouldDeleteCondition; |
| public: |
| CallDtorDeleteConditional(llvm::Value *ShouldDeleteCondition) |
| : ShouldDeleteCondition(ShouldDeleteCondition) { |
| assert(ShouldDeleteCondition != NULL); |
| } |
| |
| void Emit(CodeGenFunction &CGF, Flags flags) { |
| llvm::BasicBlock *callDeleteBB = CGF.createBasicBlock("dtor.call_delete"); |
| llvm::BasicBlock *continueBB = CGF.createBasicBlock("dtor.continue"); |
| llvm::Value *ShouldCallDelete |
| = CGF.Builder.CreateIsNull(ShouldDeleteCondition); |
| CGF.Builder.CreateCondBr(ShouldCallDelete, continueBB, callDeleteBB); |
| |
| CGF.EmitBlock(callDeleteBB); |
| const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CGF.CurCodeDecl); |
| const CXXRecordDecl *ClassDecl = Dtor->getParent(); |
| CGF.EmitDeleteCall(Dtor->getOperatorDelete(), CGF.LoadCXXThis(), |
| CGF.getContext().getTagDeclType(ClassDecl)); |
| CGF.Builder.CreateBr(continueBB); |
| |
| CGF.EmitBlock(continueBB); |
| } |
| }; |
| |
| class DestroyField : public EHScopeStack::Cleanup { |
| const FieldDecl *field; |
| CodeGenFunction::Destroyer *destroyer; |
| bool useEHCleanupForArray; |
| |
| public: |
| DestroyField(const FieldDecl *field, CodeGenFunction::Destroyer *destroyer, |
| bool useEHCleanupForArray) |
| : field(field), destroyer(destroyer), |
| useEHCleanupForArray(useEHCleanupForArray) {} |
| |
| void Emit(CodeGenFunction &CGF, Flags flags) { |
| // Find the address of the field. |
| llvm::Value *thisValue = CGF.LoadCXXThis(); |
| QualType RecordTy = CGF.getContext().getTagDeclType(field->getParent()); |
| LValue ThisLV = CGF.MakeAddrLValue(thisValue, RecordTy); |
| LValue LV = CGF.EmitLValueForField(ThisLV, field); |
| assert(LV.isSimple()); |
| |
| CGF.emitDestroy(LV.getAddress(), field->getType(), destroyer, |
| flags.isForNormalCleanup() && useEHCleanupForArray); |
| } |
| }; |
| } |
| |
| /// 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"); |
| if (CXXStructorImplicitParamValue) { |
| // If there is an implicit param to the deleting dtor, it's a boolean |
| // telling whether we should call delete at the end of the dtor. |
| EHStack.pushCleanup<CallDtorDeleteConditional>( |
| NormalAndEHCleanup, CXXStructorImplicitParamValue); |
| } else { |
| EHStack.pushCleanup<CallDtorDelete>(NormalAndEHCleanup); |
| } |
| return; |
| } |
| |
| const CXXRecordDecl *ClassDecl = DD->getParent(); |
| |
| // Unions have no bases and do not call field destructors. |
| if (ClassDecl->isUnion()) |
| return; |
| |
| // 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. |
| 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 type = field->getType(); |
| QualType::DestructionKind dtorKind = type.isDestructedType(); |
| if (!dtorKind) continue; |
| |
| // Anonymous union members do not have their destructors called. |
| const RecordType *RT = type->getAsUnionType(); |
| if (RT && RT->getDecl()->isAnonymousStructOrUnion()) continue; |
| |
| CleanupKind cleanupKind = getCleanupKind(dtorKind); |
| EHStack.pushCleanup<DestroyField>(cleanupKind, field, |
| getDestroyer(dtorKind), |
| cleanupKind & EHCleanup); |
| } |
| } |
| |
| /// EmitCXXAggrConstructorCall - Emit a loop to call a particular |
| /// constructor for each of several members of an array. |
| /// |
| /// \param ctor the constructor to call for each element |
| /// \param arrayType the type of the array to initialize |
| /// \param arrayBegin an arrayType* |
| /// \param zeroInitialize true if each element should be |
| /// zero-initialized before it is constructed |
| void |
| CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *ctor, |
| const ConstantArrayType *arrayType, |
| llvm::Value *arrayBegin, |
| CallExpr::const_arg_iterator argBegin, |
| CallExpr::const_arg_iterator argEnd, |
| bool zeroInitialize) { |
| QualType elementType; |
| llvm::Value *numElements = |
| emitArrayLength(arrayType, elementType, arrayBegin); |
| |
| EmitCXXAggrConstructorCall(ctor, numElements, arrayBegin, |
| argBegin, argEnd, zeroInitialize); |
| } |
| |
| /// EmitCXXAggrConstructorCall - Emit a loop to call a particular |
| /// constructor for each of several members of an array. |
| /// |
| /// \param ctor the constructor to call for each element |
| /// \param numElements the number of elements in the array; |
| /// may be zero |
| /// \param arrayBegin a T*, where T is the type constructed by ctor |
| /// \param zeroInitialize true if each element should be |
| /// zero-initialized before it is constructed |
| void |
| CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *ctor, |
| llvm::Value *numElements, |
| llvm::Value *arrayBegin, |
| CallExpr::const_arg_iterator argBegin, |
| CallExpr::const_arg_iterator argEnd, |
| bool zeroInitialize) { |
| |
| // It's legal for numElements to be zero. This can happen both |
| // dynamically, because x can be zero in 'new A[x]', and statically, |
| // because of GCC extensions that permit zero-length arrays. There |
| // are probably legitimate places where we could assume that this |
| // doesn't happen, but it's not clear that it's worth it. |
| llvm::BranchInst *zeroCheckBranch = 0; |
| |
| // Optimize for a constant count. |
| llvm::ConstantInt *constantCount |
| = dyn_cast<llvm::ConstantInt>(numElements); |
| if (constantCount) { |
| // Just skip out if the constant count is zero. |
| if (constantCount->isZero()) return; |
| |
| // Otherwise, emit the check. |
| } else { |
| llvm::BasicBlock *loopBB = createBasicBlock("new.ctorloop"); |
| llvm::Value *iszero = Builder.CreateIsNull(numElements, "isempty"); |
| zeroCheckBranch = Builder.CreateCondBr(iszero, loopBB, loopBB); |
| EmitBlock(loopBB); |
| } |
| |
| // Find the end of the array. |
| llvm::Value *arrayEnd = Builder.CreateInBoundsGEP(arrayBegin, numElements, |
| "arrayctor.end"); |
| |
| // Enter the loop, setting up a phi for the current location to initialize. |
| llvm::BasicBlock *entryBB = Builder.GetInsertBlock(); |
| llvm::BasicBlock *loopBB = createBasicBlock("arrayctor.loop"); |
| EmitBlock(loopBB); |
| llvm::PHINode *cur = Builder.CreatePHI(arrayBegin->getType(), 2, |
| "arrayctor.cur"); |
| cur->addIncoming(arrayBegin, entryBB); |
| |
| // Inside the loop body, emit the constructor call on the array element. |
| |
| QualType type = getContext().getTypeDeclType(ctor->getParent()); |
| |
| // Zero initialize the storage, if requested. |
| if (zeroInitialize) |
| EmitNullInitialization(cur, type); |
| |
| // 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. |
| |
| { |
| RunCleanupsScope Scope(*this); |
| |
| // Evaluate the constructor and its arguments in a regular |
| // partial-destroy cleanup. |
| if (getLangOpts().Exceptions && |
| !ctor->getParent()->hasTrivialDestructor()) { |
| Destroyer *destroyer = destroyCXXObject; |
| pushRegularPartialArrayCleanup(arrayBegin, cur, type, *destroyer); |
| } |
| |
| EmitCXXConstructorCall(ctor, Ctor_Complete, /*ForVirtualBase=*/ false, |
| /*Delegating=*/false, cur, argBegin, argEnd); |
| } |
| |
| // Go to the next element. |
| llvm::Value *next = |
| Builder.CreateInBoundsGEP(cur, llvm::ConstantInt::get(SizeTy, 1), |
| "arrayctor.next"); |
| cur->addIncoming(next, Builder.GetInsertBlock()); |
| |
| // Check whether that's the end of the loop. |
| llvm::Value *done = Builder.CreateICmpEQ(next, arrayEnd, "arrayctor.done"); |
| llvm::BasicBlock *contBB = createBasicBlock("arrayctor.cont"); |
| Builder.CreateCondBr(done, contBB, loopBB); |
| |
| // Patch the earlier check to skip over the loop. |
| if (zeroCheckBranch) zeroCheckBranch->setSuccessor(0, contBB); |
| |
| EmitBlock(contBB); |
| } |
| |
| void CodeGenFunction::destroyCXXObject(CodeGenFunction &CGF, |
| llvm::Value *addr, |
| QualType type) { |
| const RecordType *rtype = type->castAs<RecordType>(); |
| const CXXRecordDecl *record = cast<CXXRecordDecl>(rtype->getDecl()); |
| const CXXDestructorDecl *dtor = record->getDestructor(); |
| assert(!dtor->isTrivial()); |
| CGF.EmitCXXDestructorCall(dtor, Dtor_Complete, /*for vbase*/ false, |
| /*Delegating=*/false, addr); |
| } |
| |
| void |
| CodeGenFunction::EmitCXXConstructorCall(const CXXConstructorDecl *D, |
| CXXCtorType Type, bool ForVirtualBase, |
| bool Delegating, |
| llvm::Value *This, |
| CallExpr::const_arg_iterator ArgBeg, |
| CallExpr::const_arg_iterator ArgEnd) { |
| |
| CGDebugInfo *DI = getDebugInfo(); |
| if (DI && |
| CGM.getCodeGenOpts().getDebugInfo() == CodeGenOptions::LimitedDebugInfo) { |
| // If debug info for this class has not been emitted then this is the |
| // right time to do so. |
| const CXXRecordDecl *Parent = D->getParent(); |
| DI->getOrCreateRecordType(CGM.getContext().getTypeDeclType(Parent), |
| Parent->getLocation()); |
| } |
| |
| 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->isCopyOrMoveConstructor() && |
| "trivial 1-arg ctor not a copy/move 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, |
| Delegating); |
| llvm::Value *Callee = CGM.GetAddrOfCXXConstructor(D, Type); |
| |
| // FIXME: Provide a source location here. |
| EmitCXXMemberCall(D, SourceLocation(), Callee, ReturnValueSlot(), This, |
| VTT, getContext().getPointerType(getContext().VoidPtrTy), |
| 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->isCopyOrMoveConstructor() && |
| "trivial 1-arg ctor not a copy/move 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.add(RValue::get(This), D->getThisType(getContext())); |
| |
| |
| // Push the src ptr. |
| QualType QT = *(FPT->arg_type_begin()); |
| llvm::Type *t = CGM.getTypes().ConvertType(QT); |
| Src = Builder.CreateBitCast(Src, t); |
| Args.add(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!"); |
| EmitCallArg(Args, *Arg, *I); |
| } |
| // 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(); |
| EmitCallArg(Args, *Arg, ArgType); |
| } |
| |
| EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, RequiredArgs::All), |
| 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.add(RValue::get(LoadCXXThis()), (*I)->getType()); |
| ++I; |
| |
| // vtt |
| if (llvm::Value *VTT = GetVTTParameter(*this, GlobalDecl(Ctor, CtorType), |
| /*ForVirtualBase=*/false, |
| /*Delegating=*/true)) { |
| QualType VoidPP = getContext().getPointerType(getContext().VoidPtrTy); |
| DelegateArgs.add(RValue::get(VTT), VoidPP); |
| |
| if (CodeGenVTables::needsVTTParameter(CurGD)) { |
| assert(I != E && "cannot skip vtt parameter, already done with args"); |
| assert((*I)->getType() == VoidPP && "skipping parameter not of vtt type"); |
| ++I; |
| } |
| } |
| |
| // Explicit arguments. |
| for (; I != E; ++I) { |
| const VarDecl *param = *I; |
| EmitDelegateCallArg(DelegateArgs, param); |
| } |
| |
| EmitCall(CGM.getTypes().arrangeCXXConstructorDeclaration(Ctor, CtorType), |
| CGM.GetAddrOfCXXConstructor(Ctor, CtorType), |
| ReturnValueSlot(), DelegateArgs, Ctor); |
| } |
| |
| namespace { |
| struct CallDelegatingCtorDtor : EHScopeStack::Cleanup { |
| const CXXDestructorDecl *Dtor; |
| llvm::Value *Addr; |
| CXXDtorType Type; |
| |
| CallDelegatingCtorDtor(const CXXDestructorDecl *D, llvm::Value *Addr, |
| CXXDtorType Type) |
| : Dtor(D), Addr(Addr), Type(Type) {} |
| |
| void Emit(CodeGenFunction &CGF, Flags flags) { |
| CGF.EmitCXXDestructorCall(Dtor, Type, /*ForVirtualBase=*/false, |
| /*Delegating=*/true, Addr); |
| } |
| }; |
| } |
| |
| void |
| CodeGenFunction::EmitDelegatingCXXConstructorCall(const CXXConstructorDecl *Ctor, |
| const FunctionArgList &Args) { |
| assert(Ctor->isDelegatingConstructor()); |
| |
| llvm::Value *ThisPtr = LoadCXXThis(); |
| |
| QualType Ty = getContext().getTagDeclType(Ctor->getParent()); |
| CharUnits Alignment = getContext().getTypeAlignInChars(Ty); |
| AggValueSlot AggSlot = |
| AggValueSlot::forAddr(ThisPtr, Alignment, Qualifiers(), |
| AggValueSlot::IsDestructed, |
| AggValueSlot::DoesNotNeedGCBarriers, |
| AggValueSlot::IsNotAliased); |
| |
| EmitAggExpr(Ctor->init_begin()[0]->getInit(), AggSlot); |
| |
| const CXXRecordDecl *ClassDecl = Ctor->getParent(); |
| if (CGM.getLangOpts().Exceptions && !ClassDecl->hasTrivialDestructor()) { |
| CXXDtorType Type = |
| CurGD.getCtorType() == Ctor_Complete ? Dtor_Complete : Dtor_Base; |
| |
| EHStack.pushCleanup<CallDelegatingCtorDtor>(EHCleanup, |
| ClassDecl->getDestructor(), |
| ThisPtr, Type); |
| } |
| } |
| |
| void CodeGenFunction::EmitCXXDestructorCall(const CXXDestructorDecl *DD, |
| CXXDtorType Type, |
| bool ForVirtualBase, |
| bool Delegating, |
| llvm::Value *This) { |
| llvm::Value *VTT = GetVTTParameter(*this, GlobalDecl(DD, Type), |
| ForVirtualBase, Delegating); |
| llvm::Value *Callee = 0; |
| if (getLangOpts().AppleKext) |
| Callee = BuildAppleKextVirtualDestructorCall(DD, Type, |
| DD->getParent()); |
| |
| if (!Callee) |
| Callee = CGM.GetAddrOfCXXDestructor(DD, Type); |
| |
| // FIXME: Provide a source location here. |
| EmitCXXMemberCall(DD, SourceLocation(), Callee, ReturnValueSlot(), This, |
| VTT, getContext().getPointerType(getContext().VoidPtrTy), |
| 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, Flags flags) { |
| CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete, |
| /*ForVirtualBase=*/false, |
| /*Delegating=*/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(); |
| assert(D && D->isUsed() && "destructor not marked as used!"); |
| PushDestructorCleanup(D, Addr); |
| } |
| |
| llvm::Value * |
| CodeGenFunction::GetVirtualBaseClassOffset(llvm::Value *This, |
| const CXXRecordDecl *ClassDecl, |
| const CXXRecordDecl *BaseClassDecl) { |
| llvm::Value *VTablePtr = GetVTablePtr(This, Int8PtrTy); |
| CharUnits VBaseOffsetOffset = |
| CGM.getVTableContext().getVirtualBaseOffsetOffset(ClassDecl, BaseClassDecl); |
| |
| llvm::Value *VBaseOffsetPtr = |
| Builder.CreateConstGEP1_64(VTablePtr, VBaseOffsetOffset.getQuantity(), |
| "vbase.offset.ptr"); |
| 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, |
| CharUnits 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.getVTableContext().getVTableLayout(VTableClass).getAddressPoint(Base); |
| VTableAddressPoint = |
| Builder.CreateConstInBoundsGEP2_64(VTable, 0, AddressPoint); |
| } |
| |
| // Compute where to store the address point. |
| llvm::Value *VirtualOffset = 0; |
| CharUnits NonVirtualOffset = CharUnits::Zero(); |
| |
| 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; |
| } else { |
| // We can just use the base offset in the complete class. |
| NonVirtualOffset = Base.getBaseOffset(); |
| } |
| |
| // Apply the offsets. |
| llvm::Value *VTableField = LoadCXXThis(); |
| |
| if (!NonVirtualOffset.isZero() || VirtualOffset) |
| VTableField = ApplyNonVirtualAndVirtualOffset(*this, VTableField, |
| NonVirtualOffset, |
| VirtualOffset); |
| |
| // Finally, store the address point. |
| llvm::Type *AddressPointPtrTy = |
| VTableAddressPoint->getType()->getPointerTo(); |
| VTableField = Builder.CreateBitCast(VTableField, AddressPointPtrTy); |
| llvm::StoreInst *Store = Builder.CreateStore(VTableAddressPoint, VTableField); |
| CGM.DecorateInstruction(Store, CGM.getTBAAInfoForVTablePtr()); |
| } |
| |
| void |
| CodeGenFunction::InitializeVTablePointers(BaseSubobject Base, |
| const CXXRecordDecl *NearestVBase, |
| CharUnits 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; |
| |
| CharUnits BaseOffset; |
| CharUnits 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 = CharUnits::Zero(); |
| 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, CharUnits::Zero()), |
| /*NearestVBase=*/0, |
| /*OffsetFromNearestVBase=*/CharUnits::Zero(), |
| /*BaseIsNonVirtualPrimaryBase=*/false, |
| VTable, RD, VBases); |
| } |
| |
| llvm::Value *CodeGenFunction::GetVTablePtr(llvm::Value *This, |
| llvm::Type *Ty) { |
| llvm::Value *VTablePtrSrc = Builder.CreateBitCast(This, Ty->getPointerTo()); |
| llvm::Instruction *VTable = Builder.CreateLoad(VTablePtrSrc, "vtable"); |
| CGM.DecorateInstruction(VTable, CGM.getTBAAInfoForVTablePtr()); |
| return VTable; |
| } |
| |
| static const CXXRecordDecl *getMostDerivedClassDecl(const Expr *Base) { |
| const Expr *E = Base; |
| |
| while (true) { |
| E = E->IgnoreParens(); |
| if (const CastExpr *CE = dyn_cast<CastExpr>(E)) { |
| if (CE->getCastKind() == CK_DerivedToBase || |
| CE->getCastKind() == CK_UncheckedDerivedToBase || |
| CE->getCastKind() == CK_NoOp) { |
| E = CE->getSubExpr(); |
| continue; |
| } |
| } |
| |
| break; |
| } |
| |
| QualType DerivedType = E->getType(); |
| if (const PointerType *PTy = DerivedType->getAs<PointerType>()) |
| DerivedType = PTy->getPointeeType(); |
| |
| return cast<CXXRecordDecl>(DerivedType->castAs<RecordType>()->getDecl()); |
| } |
| |
| // FIXME: Ideally Expr::IgnoreParenNoopCasts should do this, but it doesn't do |
| // quite what we want. |
| static const Expr *skipNoOpCastsAndParens(const Expr *E) { |
| while (true) { |
| if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) { |
| E = PE->getSubExpr(); |
| continue; |
| } |
| |
| if (const CastExpr *CE = dyn_cast<CastExpr>(E)) { |
| if (CE->getCastKind() == CK_NoOp) { |
| E = CE->getSubExpr(); |
| continue; |
| } |
| } |
| if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { |
| if (UO->getOpcode() == UO_Extension) { |
| E = UO->getSubExpr(); |
| continue; |
| } |
| } |
| return E; |
| } |
| } |
| |
| /// canDevirtualizeMemberFunctionCall - Checks whether the given virtual member |
| /// function call on the given expr can be devirtualized. |
| static bool canDevirtualizeMemberFunctionCall(const Expr *Base, |
| const CXXMethodDecl *MD) { |
| // If the most derived class is marked final, we know that no subclass can |
| // override this member function and so we can devirtualize it. For example: |
| // |
| // struct A { virtual void f(); } |
| // struct B final : A { }; |
| // |
| // void f(B *b) { |
| // b->f(); |
| // } |
| // |
| const CXXRecordDecl *MostDerivedClassDecl = getMostDerivedClassDecl(Base); |
| if (MostDerivedClassDecl->hasAttr<FinalAttr>()) |
| return true; |
| |
| // If the member function is marked 'final', we know that it can't be |
| // overridden and can therefore devirtualize it. |
| if (MD->hasAttr<FinalAttr>()) |
| return true; |
| |
| // Similarly, if the class itself is marked 'final' it can't be overridden |
| // and we can therefore devirtualize the member function call. |
| if (MD->getParent()->hasAttr<FinalAttr>()) |
| return true; |
| |
| Base = skipNoOpCastsAndParens(Base); |
| if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Base)) { |
| if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) { |
| // This is a record decl. We know the type and can devirtualize it. |
| return VD->getType()->isRecordType(); |
| } |
| |
| return false; |
| } |
| |
| // We can always devirtualize calls on temporary object expressions. |
| if (isa<CXXConstructExpr>(Base)) |
| return true; |
| |
| // And calls on bound temporaries. |
| if (isa<CXXBindTemporaryExpr>(Base)) |
| return true; |
| |
| // Check if this is a call expr that returns a record type. |
| if (const CallExpr *CE = dyn_cast<CallExpr>(Base)) |
| return CE->getCallReturnType()->isRecordType(); |
| |
| // We can't devirtualize the call. |
| return false; |
| } |
| |
| static bool UseVirtualCall(ASTContext &Context, |
| const CXXOperatorCallExpr *CE, |
| const CXXMethodDecl *MD) { |
| if (!MD->isVirtual()) |
| return false; |
| |
| // When building with -fapple-kext, all calls must go through the vtable since |
| // the kernel linker can do runtime patching of vtables. |
| if (Context.getLangOpts().AppleKext) |
| return true; |
| |
| return !canDevirtualizeMemberFunctionCall(CE->getArg(0), MD); |
| } |
| |
| llvm::Value * |
| CodeGenFunction::EmitCXXOperatorMemberCallee(const CXXOperatorCallExpr *E, |
| const CXXMethodDecl *MD, |
| llvm::Value *This) { |
| llvm::FunctionType *fnType = |
| CGM.getTypes().GetFunctionType( |
| CGM.getTypes().arrangeCXXMethodDeclaration(MD)); |
| |
| if (UseVirtualCall(getContext(), E, MD)) |
| return BuildVirtualCall(MD, This, fnType); |
| |
| return CGM.GetAddrOfFunction(MD, fnType); |
| } |
| |
| void CodeGenFunction::EmitForwardingCallToLambda(const CXXRecordDecl *lambda, |
| CallArgList &callArgs) { |
| // Lookup the call operator |
| DeclarationName operatorName |
| = getContext().DeclarationNames.getCXXOperatorName(OO_Call); |
| CXXMethodDecl *callOperator = |
| cast<CXXMethodDecl>(lambda->lookup(operatorName).front()); |
| |
| // Get the address of the call operator. |
| const CGFunctionInfo &calleeFnInfo = |
| CGM.getTypes().arrangeCXXMethodDeclaration(callOperator); |
| llvm::Value *callee = |
| CGM.GetAddrOfFunction(GlobalDecl(callOperator), |
| CGM.getTypes().GetFunctionType(calleeFnInfo)); |
| |
| // Prepare the return slot. |
| const FunctionProtoType *FPT = |
| callOperator->getType()->castAs<FunctionProtoType>(); |
| QualType resultType = FPT->getResultType(); |
| ReturnValueSlot returnSlot; |
| if (!resultType->isVoidType() && |
| calleeFnInfo.getReturnInfo().getKind() == ABIArgInfo::Indirect && |
| hasAggregateLLVMType(calleeFnInfo.getReturnType())) |
| returnSlot = ReturnValueSlot(ReturnValue, resultType.isVolatileQualified()); |
| |
| // We don't need to separately arrange the call arguments because |
| // the call can't be variadic anyway --- it's impossible to forward |
| // variadic arguments. |
| |
| // Now emit our call. |
| RValue RV = EmitCall(calleeFnInfo, callee, returnSlot, |
| callArgs, callOperator); |
| |
| // If necessary, copy the returned value into the slot. |
| if (!resultType->isVoidType() && returnSlot.isNull()) |
| EmitReturnOfRValue(RV, resultType); |
| else |
| EmitBranchThroughCleanup(ReturnBlock); |
| } |
| |
| void CodeGenFunction::EmitLambdaBlockInvokeBody() { |
| const BlockDecl *BD = BlockInfo->getBlockDecl(); |
| const VarDecl *variable = BD->capture_begin()->getVariable(); |
| const CXXRecordDecl *Lambda = variable->getType()->getAsCXXRecordDecl(); |
| |
| // Start building arguments for forwarding call |
| CallArgList CallArgs; |
| |
| QualType ThisType = getContext().getPointerType(getContext().getRecordType(Lambda)); |
| llvm::Value *ThisPtr = GetAddrOfBlockDecl(variable, false); |
| CallArgs.add(RValue::get(ThisPtr), ThisType); |
| |
| // Add the rest of the parameters. |
| for (BlockDecl::param_const_iterator I = BD->param_begin(), |
| E = BD->param_end(); I != E; ++I) { |
| ParmVarDecl *param = *I; |
| EmitDelegateCallArg(CallArgs, param); |
| } |
| |
| EmitForwardingCallToLambda(Lambda, CallArgs); |
| } |
| |
| void CodeGenFunction::EmitLambdaToBlockPointerBody(FunctionArgList &Args) { |
| if (cast<CXXMethodDecl>(CurFuncDecl)->isVariadic()) { |
| // FIXME: Making this work correctly is nasty because it requires either |
| // cloning the body of the call operator or making the call operator forward. |
| CGM.ErrorUnsupported(CurFuncDecl, "lambda conversion to variadic function"); |
| return; |
| } |
| |
| EmitFunctionBody(Args); |
| } |
| |
| void CodeGenFunction::EmitLambdaDelegatingInvokeBody(const CXXMethodDecl *MD) { |
| const CXXRecordDecl *Lambda = MD->getParent(); |
| |
| // Start building arguments for forwarding call |
| CallArgList CallArgs; |
| |
| QualType ThisType = getContext().getPointerType(getContext().getRecordType(Lambda)); |
| llvm::Value *ThisPtr = llvm::UndefValue::get(getTypes().ConvertType(ThisType)); |
| CallArgs.add(RValue::get(ThisPtr), ThisType); |
| |
| // Add the rest of the parameters. |
| for (FunctionDecl::param_const_iterator I = MD->param_begin(), |
| E = MD->param_end(); I != E; ++I) { |
| ParmVarDecl *param = *I; |
| EmitDelegateCallArg(CallArgs, param); |
| } |
| |
| EmitForwardingCallToLambda(Lambda, CallArgs); |
| } |
| |
| void CodeGenFunction::EmitLambdaStaticInvokeFunction(const CXXMethodDecl *MD) { |
| if (MD->isVariadic()) { |
| // FIXME: Making this work correctly is nasty because it requires either |
| // cloning the body of the call operator or making the call operator forward. |
| CGM.ErrorUnsupported(MD, "lambda conversion to variadic function"); |
| return; |
| } |
| |
| EmitLambdaDelegatingInvokeBody(MD); |
| } |