diff options
Diffstat (limited to 'contrib/llvm/tools/clang/lib/CodeGen/CGClass.cpp')
| -rw-r--r-- | contrib/llvm/tools/clang/lib/CodeGen/CGClass.cpp | 2470 |
1 files changed, 2470 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/CodeGen/CGClass.cpp b/contrib/llvm/tools/clang/lib/CodeGen/CGClass.cpp new file mode 100644 index 0000000..c49f182 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/CodeGen/CGClass.cpp @@ -0,0 +1,2470 @@ +//===--- 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 "CGCXXABI.h" +#include "CGDebugInfo.h" +#include "CGRecordLayout.h" +#include "CodeGenFunction.h" +#include "clang/AST/CXXInheritance.h" +#include "clang/AST/DeclTemplate.h" +#include "clang/AST/EvaluatedExprVisitor.h" +#include "clang/AST/RecordLayout.h" +#include "clang/AST/StmtCXX.h" +#include "clang/Basic/TargetBuiltins.h" +#include "clang/CodeGen/CGFunctionInfo.h" +#include "clang/Frontend/CodeGenOptions.h" +#include "llvm/IR/Intrinsics.h" + +using namespace clang; +using namespace CodeGen; + +CharUnits CodeGenModule::computeNonVirtualBaseClassOffset( + const CXXRecordDecl *DerivedClass, CastExpr::path_const_iterator Start, + CastExpr::path_const_iterator End) { + CharUnits Offset = CharUnits::Zero(); + + const ASTContext &Context = getContext(); + 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(ClassDecl, PathBegin, PathEnd); + if (Offset.isZero()) + return nullptr; + + 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 != nullptr); + + // 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, + SourceLocation Loc) { + assert(PathBegin != PathEnd && "Base path should not be empty!"); + + CastExpr::path_const_iterator Start = PathBegin; + const CXXRecordDecl *VBase = nullptr; + + // 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 = CGM.computeNonVirtualBaseClassOffset( + 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 = nullptr; // we no longer have a virtual step + } + + // Get the base pointer type. + llvm::Type *BasePtrTy = + ConvertType((PathEnd[-1])->getType())->getPointerTo(); + + QualType DerivedTy = getContext().getRecordType(Derived); + CharUnits DerivedAlign = getContext().getTypeAlignInChars(DerivedTy); + + // 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) { + if (sanitizePerformTypeCheck()) { + EmitTypeCheck(TCK_Upcast, Loc, Value, DerivedTy, DerivedAlign, + !NullCheckValue); + } + return Builder.CreateBitCast(Value, BasePtrTy); + } + + llvm::BasicBlock *origBB = nullptr; + llvm::BasicBlock *endBB = nullptr; + + // 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); + } + + if (sanitizePerformTypeCheck()) { + EmitTypeCheck(VBase ? TCK_UpcastToVirtualBase : TCK_Upcast, Loc, Value, + DerivedTy, DerivedAlign, true); + } + + // Compute the virtual offset. + llvm::Value *VirtualOffset = nullptr; + if (VBase) { + VirtualOffset = + CGM.getCXXABI().GetVirtualBaseClassOffset(*this, 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 = nullptr; + llvm::BasicBlock *CastNotNull = nullptr; + llvm::BasicBlock *CastEnd = nullptr; + + 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; +} + +llvm::Value *CodeGenFunction::GetVTTParameter(GlobalDecl GD, + bool ForVirtualBase, + bool Delegating) { + if (!CGM.getCXXABI().NeedsVTTParameter(GD)) { + // This constructor/destructor does not need a VTT parameter. + return nullptr; + } + + const CXXRecordDecl *RD = cast<CXXMethodDecl>(CurCodeDecl)->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 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(!CGM.getCXXABI().NeedsVTTParameter(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 = getContext().getASTRecordLayout(RD); + CharUnits BaseOffset = ForVirtualBase ? + Layout.getVBaseClassOffset(Base) : + Layout.getBaseClassOffset(Base); + + SubVTTIndex = + CGM.getVTables().getSubVTTIndex(RD, BaseSubobject(Base, BaseOffset)); + assert(SubVTTIndex != 0 && "Sub-VTT index must be greater than zero!"); + } + + if (CGM.getCXXABI().NeedsVTTParameter(CurGD)) { + // A VTT parameter was passed to the constructor, use it. + VTT = LoadCXXVTT(); + VTT = Builder.CreateConstInBoundsGEP1_64(VTT, SubVTTIndex); + } else { + // We're the complete constructor, so get the VTT by name. + VTT = CGM.getVTables().GetAddrOfVTT(RD); + VTT = 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) override { + 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 : ConstEvaluatedExprVisitor<DynamicThisUseChecker> { + typedef ConstEvaluatedExprVisitor<DynamicThisUseChecker> super; + + bool UsesThis; + + DynamicThisUseChecker(const 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(const CXXThisExpr *E) { UsesThis = true; } + }; +} + +static bool BaseInitializerUsesThis(ASTContext &C, const Expr *Init) { + DynamicThisUseChecker Checker(C); + Checker.Visit(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; + + 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())); + } + + switch (CGF.getEvaluationKind(T)) { + case TEK_Scalar: + CGF.EmitScalarInit(Init, /*decl*/ nullptr, LV, false); + break; + case TEK_Complex: + CGF.EmitComplexExprIntoLValue(Init, LV, /*isInit*/ true); + break; + case TEK_Aggregate: { + AggValueSlot Slot = + AggValueSlot::forLValue(LV, + AggValueSlot::IsDestructed, + AggValueSlot::DoesNotNeedGCBarriers, + AggValueSlot::IsNotAliased); + + CGF.EmitAggExpr(Init, Slot); + break; + } + } + + 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"); + + // 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 bool isMemcpyEquivalentSpecialMember(const CXXMethodDecl *D) { + auto *CD = dyn_cast<CXXConstructorDecl>(D); + if (!(CD && CD->isCopyOrMoveConstructor()) && + !D->isCopyAssignmentOperator() && !D->isMoveAssignmentOperator()) + return false; + + // We can emit a memcpy for a trivial copy or move constructor/assignment. + if (D->isTrivial() && !D->getParent()->mayInsertExtraPadding()) + return true; + + // We *must* emit a memcpy for a defaulted union copy or move op. + if (D->getParent()->isUnion() && D->isDefaulted()) + return true; + + return false; +} + +static void EmitLValueForAnyFieldInitialization(CodeGenFunction &CGF, + CXXCtorInitializer *MemberInit, + LValue &LHS) { + FieldDecl *Field = MemberInit->getAnyMember(); + if (MemberInit->isIndirectMemberInitializer()) { + // If we are initializing an anonymous union field, drill down to the field. + IndirectFieldDecl *IndirectField = MemberInit->getIndirectMember(); + for (const auto *I : IndirectField->chain()) + LHS = CGF.EmitLValueForFieldInitialization(LHS, cast<FieldDecl>(I)); + } else { + LHS = CGF.EmitLValueForFieldInitialization(LHS, Field); + } +} + +static void EmitMemberInitializer(CodeGenFunction &CGF, + const CXXRecordDecl *ClassDecl, + CXXCtorInitializer *MemberInit, + const CXXConstructorDecl *Constructor, + FunctionArgList &Args) { + ApplyDebugLocation Loc(CGF, MemberInit->getSourceLocation()); + 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); + + EmitLValueForAnyFieldInitialization(CGF, MemberInit, LHS); + + // 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->isDefaulted() && + Constructor->isCopyOrMoveConstructor()) { + QualType BaseElementTy = CGF.getContext().getBaseElementType(Array); + CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(MemberInit->getInit()); + if (BaseElementTy.isPODType(CGF.getContext()) || + (CE && isMemcpyEquivalentSpecialMember(CE->getConstructor()))) { + unsigned SrcArgIndex = + CGF.CGM.getCXXABI().getSrcArgforCopyCtor(Constructor, Args); + 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()); + // Ensure that we destroy the objects if an exception is thrown later in + // the constructor. + QualType::DestructionKind dtorKind = FieldType.isDestructedType(); + if (CGF.needsEHCleanup(dtorKind)) + CGF.pushEHDestroy(dtorKind, LHS.getAddress(), FieldType); + 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(); + switch (getEvaluationKind(FieldType)) { + case TEK_Scalar: + if (LHS.isSimple()) { + EmitExprAsInit(Init, Field, LHS, false); + } else { + RValue RHS = RValue::get(EmitScalarExpr(Init)); + EmitStoreThroughLValue(RHS, LHS); + } + break; + case TEK_Complex: + EmitComplexExprIntoLValue(Init, LHS, /*isInit*/ true); + break; + case TEK_Aggregate: { + llvm::Value *ArrayIndexVar = nullptr; + 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; +} + +// Emit code in ctor (Prologue==true) or dtor (Prologue==false) +// to poison the extra field paddings inserted under +// -fsanitize-address-field-padding=1|2. +void CodeGenFunction::EmitAsanPrologueOrEpilogue(bool Prologue) { + ASTContext &Context = getContext(); + const CXXRecordDecl *ClassDecl = + Prologue ? cast<CXXConstructorDecl>(CurGD.getDecl())->getParent() + : cast<CXXDestructorDecl>(CurGD.getDecl())->getParent(); + if (!ClassDecl->mayInsertExtraPadding()) return; + + struct SizeAndOffset { + uint64_t Size; + uint64_t Offset; + }; + + unsigned PtrSize = CGM.getDataLayout().getPointerSizeInBits(); + const ASTRecordLayout &Info = Context.getASTRecordLayout(ClassDecl); + + // Populate sizes and offsets of fields. + SmallVector<SizeAndOffset, 16> SSV(Info.getFieldCount()); + for (unsigned i = 0, e = Info.getFieldCount(); i != e; ++i) + SSV[i].Offset = + Context.toCharUnitsFromBits(Info.getFieldOffset(i)).getQuantity(); + + size_t NumFields = 0; + for (const auto *Field : ClassDecl->fields()) { + const FieldDecl *D = Field; + std::pair<CharUnits, CharUnits> FieldInfo = + Context.getTypeInfoInChars(D->getType()); + CharUnits FieldSize = FieldInfo.first; + assert(NumFields < SSV.size()); + SSV[NumFields].Size = D->isBitField() ? 0 : FieldSize.getQuantity(); + NumFields++; + } + assert(NumFields == SSV.size()); + if (SSV.size() <= 1) return; + + // We will insert calls to __asan_* run-time functions. + // LLVM AddressSanitizer pass may decide to inline them later. + llvm::Type *Args[2] = {IntPtrTy, IntPtrTy}; + llvm::FunctionType *FTy = + llvm::FunctionType::get(CGM.VoidTy, Args, false); + llvm::Constant *F = CGM.CreateRuntimeFunction( + FTy, Prologue ? "__asan_poison_intra_object_redzone" + : "__asan_unpoison_intra_object_redzone"); + + llvm::Value *ThisPtr = LoadCXXThis(); + ThisPtr = Builder.CreatePtrToInt(ThisPtr, IntPtrTy); + uint64_t TypeSize = Info.getNonVirtualSize().getQuantity(); + // For each field check if it has sufficient padding, + // if so (un)poison it with a call. + for (size_t i = 0; i < SSV.size(); i++) { + uint64_t AsanAlignment = 8; + uint64_t NextField = i == SSV.size() - 1 ? TypeSize : SSV[i + 1].Offset; + uint64_t PoisonSize = NextField - SSV[i].Offset - SSV[i].Size; + uint64_t EndOffset = SSV[i].Offset + SSV[i].Size; + if (PoisonSize < AsanAlignment || !SSV[i].Size || + (NextField % AsanAlignment) != 0) + continue; + Builder.CreateCall( + F, {Builder.CreateAdd(ThisPtr, Builder.getIntN(PtrSize, EndOffset)), + Builder.getIntN(PtrSize, PoisonSize)}); + } +} + +/// EmitConstructorBody - Emits the body of the current constructor. +void CodeGenFunction::EmitConstructorBody(FunctionArgList &Args) { + EmitAsanPrologueOrEpilogue(true); + const CXXConstructorDecl *Ctor = cast<CXXConstructorDecl>(CurGD.getDecl()); + CXXCtorType CtorType = CurGD.getCtorType(); + + assert((CGM.getTarget().getCXXABI().hasConstructorVariants() || + CtorType == Ctor_Complete) && + "can only generate complete ctor for this ABI"); + + // Before we go any further, try the complete->base constructor + // delegation optimization. + if (CtorType == Ctor_Complete && IsConstructorDelegationValid(Ctor) && + CGM.getTarget().getCXXABI().hasConstructorVariants()) { + EmitDelegateCXXConstructorCall(Ctor, Ctor_Base, Args, Ctor->getLocEnd()); + return; + } + + const FunctionDecl *Definition = 0; + Stmt *Body = Ctor->getBody(Definition); + assert(Definition == Ctor && "emitting wrong constructor body"); + + // Enter the function-try-block before the constructor prologue if + // applicable. + bool IsTryBody = (Body && isa<CXXTryStmt>(Body)); + if (IsTryBody) + EnterCXXTryStmt(*cast<CXXTryStmt>(Body), true); + + incrementProfileCounter(Body); + + RunCleanupsScope RunCleanups(*this); + + // 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. + RunCleanups.ForceCleanup(); + + if (IsTryBody) + ExitCXXTryStmt(*cast<CXXTryStmt>(Body), true); +} + +namespace { + /// RAII object to indicate that codegen is copying the value representation + /// instead of the object representation. Useful when copying a struct or + /// class which has uninitialized members and we're only performing + /// lvalue-to-rvalue conversion on the object but not its members. + class CopyingValueRepresentation { + public: + explicit CopyingValueRepresentation(CodeGenFunction &CGF) + : CGF(CGF), OldSanOpts(CGF.SanOpts) { + CGF.SanOpts.set(SanitizerKind::Bool, false); + CGF.SanOpts.set(SanitizerKind::Enum, false); + } + ~CopyingValueRepresentation() { + CGF.SanOpts = OldSanOpts; + } + private: + CodeGenFunction &CGF; + SanitizerSet OldSanOpts; + }; +} + +namespace { + class FieldMemcpyizer { + public: + FieldMemcpyizer(CodeGenFunction &CGF, const CXXRecordDecl *ClassDecl, + const VarDecl *SrcRec) + : CGF(CGF), ClassDecl(ClassDecl), SrcRec(SrcRec), + RecLayout(CGF.getContext().getASTRecordLayout(ClassDecl)), + FirstField(nullptr), LastField(nullptr), FirstFieldOffset(0), + LastFieldOffset(0), LastAddedFieldIndex(0) {} + + bool isMemcpyableField(FieldDecl *F) const { + // Never memcpy fields when we are adding poisoned paddings. + if (CGF.getContext().getLangOpts().SanitizeAddressFieldPadding) + return false; + Qualifiers Qual = F->getType().getQualifiers(); + if (Qual.hasVolatile() || Qual.hasObjCLifetime()) + return false; + return true; + } + + void addMemcpyableField(FieldDecl *F) { + if (!FirstField) + addInitialField(F); + else + addNextField(F); + } + + CharUnits getMemcpySize(uint64_t FirstByteOffset) const { + unsigned LastFieldSize = + LastField->isBitField() ? + LastField->getBitWidthValue(CGF.getContext()) : + CGF.getContext().getTypeSize(LastField->getType()); + uint64_t MemcpySizeBits = + LastFieldOffset + LastFieldSize - FirstByteOffset + + CGF.getContext().getCharWidth() - 1; + CharUnits MemcpySize = + CGF.getContext().toCharUnitsFromBits(MemcpySizeBits); + return MemcpySize; + } + + void emitMemcpy() { + // Give the subclass a chance to bail out if it feels the memcpy isn't + // worth it (e.g. Hasn't aggregated enough data). + if (!FirstField) { + return; + } + + uint64_t FirstByteOffset; + if (FirstField->isBitField()) { + const CGRecordLayout &RL = + CGF.getTypes().getCGRecordLayout(FirstField->getParent()); + const CGBitFieldInfo &BFInfo = RL.getBitFieldInfo(FirstField); + // FirstFieldOffset is not appropriate for bitfields, + // we need to use the storage offset instead. + FirstByteOffset = CGF.getContext().toBits(BFInfo.StorageOffset); + } else { + FirstByteOffset = FirstFieldOffset; + } + + CharUnits MemcpySize = getMemcpySize(FirstByteOffset); + QualType RecordTy = CGF.getContext().getTypeDeclType(ClassDecl); + llvm::Value *ThisPtr = CGF.LoadCXXThis(); + LValue DestLV = CGF.MakeNaturalAlignAddrLValue(ThisPtr, RecordTy); + LValue Dest = CGF.EmitLValueForFieldInitialization(DestLV, FirstField); + llvm::Value *SrcPtr = CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(SrcRec)); + LValue SrcLV = CGF.MakeNaturalAlignAddrLValue(SrcPtr, RecordTy); + LValue Src = CGF.EmitLValueForFieldInitialization(SrcLV, FirstField); + + CharUnits Offset = CGF.getContext().toCharUnitsFromBits(FirstByteOffset); + CharUnits Alignment = DestLV.getAlignment().alignmentAtOffset(Offset); + + emitMemcpyIR(Dest.isBitField() ? Dest.getBitFieldAddr() : Dest.getAddress(), + Src.isBitField() ? Src.getBitFieldAddr() : Src.getAddress(), + MemcpySize, Alignment); + reset(); + } + + void reset() { + FirstField = nullptr; + } + + protected: + CodeGenFunction &CGF; + const CXXRecordDecl *ClassDecl; + + private: + + void emitMemcpyIR(llvm::Value *DestPtr, llvm::Value *SrcPtr, + CharUnits Size, CharUnits Alignment) { + llvm::PointerType *DPT = cast<llvm::PointerType>(DestPtr->getType()); + llvm::Type *DBP = + llvm::Type::getInt8PtrTy(CGF.getLLVMContext(), DPT->getAddressSpace()); + DestPtr = CGF.Builder.CreateBitCast(DestPtr, DBP); + + llvm::PointerType *SPT = cast<llvm::PointerType>(SrcPtr->getType()); + llvm::Type *SBP = + llvm::Type::getInt8PtrTy(CGF.getLLVMContext(), SPT->getAddressSpace()); + SrcPtr = CGF.Builder.CreateBitCast(SrcPtr, SBP); + + CGF.Builder.CreateMemCpy(DestPtr, SrcPtr, Size.getQuantity(), + Alignment.getQuantity()); + } + + void addInitialField(FieldDecl *F) { + FirstField = F; + LastField = F; + FirstFieldOffset = RecLayout.getFieldOffset(F->getFieldIndex()); + LastFieldOffset = FirstFieldOffset; + LastAddedFieldIndex = F->getFieldIndex(); + return; + } + + void addNextField(FieldDecl *F) { + // For the most part, the following invariant will hold: + // F->getFieldIndex() == LastAddedFieldIndex + 1 + // The one exception is that Sema won't add a copy-initializer for an + // unnamed bitfield, which will show up here as a gap in the sequence. + assert(F->getFieldIndex() >= LastAddedFieldIndex + 1 && + "Cannot aggregate fields out of order."); + LastAddedFieldIndex = F->getFieldIndex(); + + // The 'first' and 'last' fields are chosen by offset, rather than field + // index. This allows the code to support bitfields, as well as regular + // fields. + uint64_t FOffset = RecLayout.getFieldOffset(F->getFieldIndex()); + if (FOffset < FirstFieldOffset) { + FirstField = F; + FirstFieldOffset = FOffset; + } else if (FOffset > LastFieldOffset) { + LastField = F; + LastFieldOffset = FOffset; + } + } + + const VarDecl *SrcRec; + const ASTRecordLayout &RecLayout; + FieldDecl *FirstField; + FieldDecl *LastField; + uint64_t FirstFieldOffset, LastFieldOffset; + unsigned LastAddedFieldIndex; + }; + + class ConstructorMemcpyizer : public FieldMemcpyizer { + private: + + /// Get source argument for copy constructor. Returns null if not a copy + /// constructor. + static const VarDecl *getTrivialCopySource(CodeGenFunction &CGF, + const CXXConstructorDecl *CD, + FunctionArgList &Args) { + if (CD->isCopyOrMoveConstructor() && CD->isDefaulted()) + return Args[CGF.CGM.getCXXABI().getSrcArgforCopyCtor(CD, Args)]; + return nullptr; + } + + // Returns true if a CXXCtorInitializer represents a member initialization + // that can be rolled into a memcpy. + bool isMemberInitMemcpyable(CXXCtorInitializer *MemberInit) const { + if (!MemcpyableCtor) + return false; + FieldDecl *Field = MemberInit->getMember(); + assert(Field && "No field for member init."); + QualType FieldType = Field->getType(); + CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(MemberInit->getInit()); + + // Bail out on non-memcpyable, not-trivially-copyable members. + if (!(CE && isMemcpyEquivalentSpecialMember(CE->getConstructor())) && + !(FieldType.isTriviallyCopyableType(CGF.getContext()) || + FieldType->isReferenceType())) + return false; + + // Bail out on volatile fields. + if (!isMemcpyableField(Field)) + return false; + + // Otherwise we're good. + return true; + } + + public: + ConstructorMemcpyizer(CodeGenFunction &CGF, const CXXConstructorDecl *CD, + FunctionArgList &Args) + : FieldMemcpyizer(CGF, CD->getParent(), getTrivialCopySource(CGF, CD, Args)), + ConstructorDecl(CD), + MemcpyableCtor(CD->isDefaulted() && + CD->isCopyOrMoveConstructor() && + CGF.getLangOpts().getGC() == LangOptions::NonGC), + Args(Args) { } + + void addMemberInitializer(CXXCtorInitializer *MemberInit) { + if (isMemberInitMemcpyable(MemberInit)) { + AggregatedInits.push_back(MemberInit); + addMemcpyableField(MemberInit->getMember()); + } else { + emitAggregatedInits(); + EmitMemberInitializer(CGF, ConstructorDecl->getParent(), MemberInit, + ConstructorDecl, Args); + } + } + + void emitAggregatedInits() { + if (AggregatedInits.size() <= 1) { + // This memcpy is too small to be worthwhile. Fall back on default + // codegen. + if (!AggregatedInits.empty()) { + CopyingValueRepresentation CVR(CGF); + EmitMemberInitializer(CGF, ConstructorDecl->getParent(), + AggregatedInits[0], ConstructorDecl, Args); + AggregatedInits.clear(); + } + reset(); + return; + } + + pushEHDestructors(); + emitMemcpy(); + AggregatedInits.clear(); + } + + void pushEHDestructors() { + llvm::Value *ThisPtr = CGF.LoadCXXThis(); + QualType RecordTy = CGF.getContext().getTypeDeclType(ClassDecl); + LValue LHS = CGF.MakeNaturalAlignAddrLValue(ThisPtr, RecordTy); + + for (unsigned i = 0; i < AggregatedInits.size(); ++i) { + CXXCtorInitializer *MemberInit = AggregatedInits[i]; + QualType FieldType = MemberInit->getAnyMember()->getType(); + QualType::DestructionKind dtorKind = FieldType.isDestructedType(); + if (!CGF.needsEHCleanup(dtorKind)) + continue; + LValue FieldLHS = LHS; + EmitLValueForAnyFieldInitialization(CGF, MemberInit, FieldLHS); + CGF.pushEHDestroy(dtorKind, FieldLHS.getAddress(), FieldType); + } + } + + void finish() { + emitAggregatedInits(); + } + + private: + const CXXConstructorDecl *ConstructorDecl; + bool MemcpyableCtor; + FunctionArgList &Args; + SmallVector<CXXCtorInitializer*, 16> AggregatedInits; + }; + + class AssignmentMemcpyizer : public FieldMemcpyizer { + private: + + // Returns the memcpyable field copied by the given statement, if one + // exists. Otherwise returns null. + FieldDecl *getMemcpyableField(Stmt *S) { + if (!AssignmentsMemcpyable) + return nullptr; + if (BinaryOperator *BO = dyn_cast<BinaryOperator>(S)) { + // Recognise trivial assignments. + if (BO->getOpcode() != BO_Assign) + return nullptr; + MemberExpr *ME = dyn_cast<MemberExpr>(BO->getLHS()); + if (!ME) + return nullptr; + FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl()); + if (!Field || !isMemcpyableField(Field)) + return nullptr; + Stmt *RHS = BO->getRHS(); + if (ImplicitCastExpr *EC = dyn_cast<ImplicitCastExpr>(RHS)) + RHS = EC->getSubExpr(); + if (!RHS) + return nullptr; + MemberExpr *ME2 = dyn_cast<MemberExpr>(RHS); + if (dyn_cast<FieldDecl>(ME2->getMemberDecl()) != Field) + return nullptr; + return Field; + } else if (CXXMemberCallExpr *MCE = dyn_cast<CXXMemberCallExpr>(S)) { + CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MCE->getCalleeDecl()); + if (!(MD && isMemcpyEquivalentSpecialMember(MD))) + return nullptr; + MemberExpr *IOA = dyn_cast<MemberExpr>(MCE->getImplicitObjectArgument()); + if (!IOA) + return nullptr; + FieldDecl *Field = dyn_cast<FieldDecl>(IOA->getMemberDecl()); + if (!Field || !isMemcpyableField(Field)) + return nullptr; + MemberExpr *Arg0 = dyn_cast<MemberExpr>(MCE->getArg(0)); + if (!Arg0 || Field != dyn_cast<FieldDecl>(Arg0->getMemberDecl())) + return nullptr; + return Field; + } else if (CallExpr *CE = dyn_cast<CallExpr>(S)) { + FunctionDecl *FD = dyn_cast<FunctionDecl>(CE->getCalleeDecl()); + if (!FD || FD->getBuiltinID() != Builtin::BI__builtin_memcpy) + return nullptr; + Expr *DstPtr = CE->getArg(0); + if (ImplicitCastExpr *DC = dyn_cast<ImplicitCastExpr>(DstPtr)) + DstPtr = DC->getSubExpr(); + UnaryOperator *DUO = dyn_cast<UnaryOperator>(DstPtr); + if (!DUO || DUO->getOpcode() != UO_AddrOf) + return nullptr; + MemberExpr *ME = dyn_cast<MemberExpr>(DUO->getSubExpr()); + if (!ME) + return nullptr; + FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl()); + if (!Field || !isMemcpyableField(Field)) + return nullptr; + Expr *SrcPtr = CE->getArg(1); + if (ImplicitCastExpr *SC = dyn_cast<ImplicitCastExpr>(SrcPtr)) + SrcPtr = SC->getSubExpr(); + UnaryOperator *SUO = dyn_cast<UnaryOperator>(SrcPtr); + if (!SUO || SUO->getOpcode() != UO_AddrOf) + return nullptr; + MemberExpr *ME2 = dyn_cast<MemberExpr>(SUO->getSubExpr()); + if (!ME2 || Field != dyn_cast<FieldDecl>(ME2->getMemberDecl())) + return nullptr; + return Field; + } + + return nullptr; + } + + bool AssignmentsMemcpyable; + SmallVector<Stmt*, 16> AggregatedStmts; + + public: + + AssignmentMemcpyizer(CodeGenFunction &CGF, const CXXMethodDecl *AD, + FunctionArgList &Args) + : FieldMemcpyizer(CGF, AD->getParent(), Args[Args.size() - 1]), + AssignmentsMemcpyable(CGF.getLangOpts().getGC() == LangOptions::NonGC) { + assert(Args.size() == 2); + } + + void emitAssignment(Stmt *S) { + FieldDecl *F = getMemcpyableField(S); + if (F) { + addMemcpyableField(F); + AggregatedStmts.push_back(S); + } else { + emitAggregatedStmts(); + CGF.EmitStmt(S); + } + } + + void emitAggregatedStmts() { + if (AggregatedStmts.size() <= 1) { + if (!AggregatedStmts.empty()) { + CopyingValueRepresentation CVR(CGF); + CGF.EmitStmt(AggregatedStmts[0]); + } + reset(); + } + + emitMemcpy(); + AggregatedStmts.clear(); + } + + void finish() { + emitAggregatedStmts(); + } + }; + +} + +/// 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(); + + CXXConstructorDecl::init_const_iterator B = CD->init_begin(), + E = CD->init_end(); + + llvm::BasicBlock *BaseCtorContinueBB = nullptr; + if (ClassDecl->getNumVBases() && + !CGM.getTarget().getCXXABI().hasConstructorVariants()) { + // The ABIs that don't have constructor variants need to put a branch + // before the virtual base initialization code. + BaseCtorContinueBB = + CGM.getCXXABI().EmitCtorCompleteObjectHandler(*this, ClassDecl); + assert(BaseCtorContinueBB); + } + + // Virtual base initializers first. + for (; B != E && (*B)->isBaseInitializer() && (*B)->isBaseVirtual(); B++) { + EmitBaseInitializer(*this, ClassDecl, *B, CtorType); + } + + if (BaseCtorContinueBB) { + // Complete object handler should continue to the remaining initializers. + Builder.CreateBr(BaseCtorContinueBB); + EmitBlock(BaseCtorContinueBB); + } + + // Then, non-virtual base initializers. + for (; B != E && (*B)->isBaseInitializer(); B++) { + assert(!(*B)->isBaseVirtual()); + EmitBaseInitializer(*this, ClassDecl, *B, CtorType); + } + + InitializeVTablePointers(ClassDecl); + + // And finally, initialize class members. + FieldConstructionScope FCS(*this, CXXThisValue); + ConstructorMemcpyizer CM(*this, CD, Args); + for (; B != E; B++) { + CXXCtorInitializer *Member = (*B); + assert(!Member->isBaseInitializer()); + assert(Member->isAnyMemberInitializer() && + "Delegating initializer on non-delegating constructor"); + CM.addMemberInitializer(Member); + } + CM.finish(); +} + +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 (const auto *Field : BaseClassDecl->fields()) + if (!FieldHasTrivialDestructorBody(Context, Field)) + return false; + + // Check non-virtual bases. + for (const auto &I : BaseClassDecl->bases()) { + 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 (const auto &I : BaseClassDecl->vbases()) { + 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()); + + // The destructor for an implicit anonymous union member is never invoked. + if (FieldClassDecl->isUnion() && FieldClassDecl->isAnonymousStructOrUnion()) + return false; + + 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 (const auto *Field : ClassDecl->fields()) + if (!FieldHasTrivialDestructorBody(Context, Field)) + return false; + + return true; +} + +// Generates function call for handling object poisoning, passing in +// references to 'this' and its size as arguments. +static void EmitDtorSanitizerCallback(CodeGenFunction &CGF, + const CXXDestructorDecl *Dtor) { + const ASTRecordLayout &Layout = + CGF.getContext().getASTRecordLayout(Dtor->getParent()); + + llvm::Value *Args[] = { + CGF.Builder.CreateBitCast(CGF.LoadCXXThis(), CGF.VoidPtrTy), + llvm::ConstantInt::get(CGF.SizeTy, Layout.getSize().getQuantity())}; + llvm::Type *ArgTypes[] = {CGF.VoidPtrTy, CGF.SizeTy}; + + llvm::FunctionType *FnType = + llvm::FunctionType::get(CGF.VoidTy, ArgTypes, false); + llvm::Value *Fn = + CGF.CGM.CreateRuntimeFunction(FnType, "__sanitizer_dtor_callback"); + CGF.EmitNounwindRuntimeCall(Fn, 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 (Body) + incrementProfileCounter(Body); + + // 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; + } + + // 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); + EmitAsanPrologueOrEpilogue(false); + + // 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. In the Microsoft ABI, we + // always delegate because we might not have a definition in this TU. + switch (DtorType) { + case Dtor_Comdat: + llvm_unreachable("not expecting a COMDAT"); + + case Dtor_Deleting: llvm_unreachable("already handled deleting case"); + + case Dtor_Complete: + assert((Body || getTarget().getCXXABI().isMicrosoft()) && + "can't emit a dtor without a body for non-Microsoft ABIs"); + + // Enter the cleanup scopes for virtual bases. + EnterDtorCleanups(Dtor, Dtor_Complete); + + if (!isTryBody) { + EmitCXXDestructorCall(Dtor, Dtor_Base, /*ForVirtualBase=*/false, + /*Delegating=*/false, LoadCXXThis()); + break; + } + // Fallthrough: act like we're in the base variant. + + case Dtor_Base: + assert(Body); + + // 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); + + // Insert memory-poisoning instrumentation. + if (CGM.getCodeGenOpts().SanitizeMemoryUseAfterDtor) + EmitDtorSanitizerCallback(*this, Dtor); +} + +void CodeGenFunction::emitImplicitAssignmentOperatorBody(FunctionArgList &Args) { + const CXXMethodDecl *AssignOp = cast<CXXMethodDecl>(CurGD.getDecl()); + const Stmt *RootS = AssignOp->getBody(); + assert(isa<CompoundStmt>(RootS) && + "Body of an implicit assignment operator should be compound stmt."); + const CompoundStmt *RootCS = cast<CompoundStmt>(RootS); + + LexicalScope Scope(*this, RootCS->getSourceRange()); + + AssignmentMemcpyizer AM(*this, AssignOp, Args); + for (auto *I : RootCS->body()) + AM.emitAssignment(I); + AM.finish(); +} + +namespace { + /// Call the operator delete associated with the current destructor. + struct CallDtorDelete : EHScopeStack::Cleanup { + CallDtorDelete() {} + + void Emit(CodeGenFunction &CGF, Flags flags) override { + 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 != nullptr); + } + + void Emit(CodeGenFunction &CGF, Flags flags) override { + 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) override { + // 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); + } + }; +} + +/// \brief 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() || DD->hasAttr<DLLExportAttr>()) && + "Should not emit dtor epilogue for non-exported 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 - EnterDtorCleanups"); + 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 (const auto &Base : ClassDecl->vbases()) { + 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 (const auto &Base : ClassDecl->bases()) { + // 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. + for (const auto *Field : ClassDecl->fields()) { + 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, const CXXConstructExpr *E, bool zeroInitialize) { + QualType elementType; + llvm::Value *numElements = + emitArrayLength(arrayType, elementType, arrayBegin); + + EmitCXXAggrConstructorCall(ctor, numElements, arrayBegin, E, 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, + const CXXConstructExpr *E, + 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 = nullptr; + + // 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, E); + } + + // 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, + const CXXConstructExpr *E) { + // C++11 [class.mfct.non-static]p2: + // If a non-static member function of a class X is called for an object that + // is not of type X, or of a type derived from X, the behavior is undefined. + // FIXME: Provide a source location here. + EmitTypeCheck(CodeGenFunction::TCK_ConstructorCall, SourceLocation(), This, + getContext().getRecordType(D->getParent())); + + if (D->isTrivial() && D->isDefaultConstructor()) { + assert(E->getNumArgs() == 0 && "trivial default ctor with args"); + return; + } + + // If this is a trivial constructor, just emit what's needed. If this is a + // union copy constructor, we must emit a memcpy, because the AST does not + // model that copy. + if (isMemcpyEquivalentSpecialMember(D)) { + assert(E->getNumArgs() == 1 && "unexpected argcount for trivial ctor"); + + const Expr *Arg = E->getArg(0); + QualType SrcTy = Arg->getType(); + llvm::Value *Src = EmitLValue(Arg).getAddress(); + QualType DestTy = getContext().getTypeDeclType(D->getParent()); + EmitAggregateCopyCtor(This, Src, DestTy, SrcTy); + return; + } + + CallArgList Args; + + // Push the this ptr. + Args.add(RValue::get(This), D->getThisType(getContext())); + + // Add the rest of the user-supplied arguments. + const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>(); + EmitCallArgs(Args, FPT, E->arg_begin(), E->arg_end(), E->getConstructor()); + + // Insert any ABI-specific implicit constructor arguments. + unsigned ExtraArgs = CGM.getCXXABI().addImplicitConstructorArgs( + *this, D, Type, ForVirtualBase, Delegating, Args); + + // Emit the call. + llvm::Value *Callee = CGM.getAddrOfCXXStructor(D, getFromCtorType(Type)); + const CGFunctionInfo &Info = + CGM.getTypes().arrangeCXXConstructorCall(Args, D, Type, ExtraArgs); + EmitCall(Info, Callee, ReturnValueSlot(), Args, D); +} + +void +CodeGenFunction::EmitSynthesizedCXXCopyCtorCall(const CXXConstructorDecl *D, + llvm::Value *This, llvm::Value *Src, + const CXXConstructExpr *E) { + if (isMemcpyEquivalentSpecialMember(D)) { + assert(E->getNumArgs() == 1 && "unexpected argcount for trivial ctor"); + assert(D->isCopyOrMoveConstructor() && + "trivial 1-arg ctor not a copy/move ctor"); + EmitAggregateCopyCtor(This, Src, + getContext().getTypeDeclType(D->getParent()), + E->arg_begin()->getType()); + return; + } + llvm::Value *Callee = CGM.getAddrOfCXXStructor(D, StructorType::Complete); + assert(D->isInstance() && + "Trying to emit a member call expr on a static method!"); + + const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>(); + + CallArgList Args; + + // Push the this ptr. + Args.add(RValue::get(This), D->getThisType(getContext())); + + // Push the src ptr. + QualType QT = *(FPT->param_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). + EmitCallArgs(Args, FPT, E->arg_begin() + 1, E->arg_end(), E->getConstructor(), + /*ParamsToSkip*/ 1); + + EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, RequiredArgs::All), + Callee, ReturnValueSlot(), Args, D); +} + +void +CodeGenFunction::EmitDelegateCXXConstructorCall(const CXXConstructorDecl *Ctor, + CXXCtorType CtorType, + const FunctionArgList &Args, + SourceLocation Loc) { + 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(GlobalDecl(Ctor, CtorType), + /*ForVirtualBase=*/false, + /*Delegating=*/true)) { + QualType VoidPP = getContext().getPointerType(getContext().VoidPtrTy); + DelegateArgs.add(RValue::get(VTT), VoidPP); + + if (CGM.getCXXABI().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; + // FIXME: per-argument source location + EmitDelegateCallArg(DelegateArgs, param, Loc); + } + + llvm::Value *Callee = + CGM.getAddrOfCXXStructor(Ctor, getFromCtorType(CtorType)); + EmitCall(CGM.getTypes() + .arrangeCXXStructorDeclaration(Ctor, getFromCtorType(CtorType)), + Callee, 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) override { + 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) { + CGM.getCXXABI().EmitDestructorCall(*this, DD, Type, ForVirtualBase, + Delegating, This); +} + +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) override { + 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); +} + +void +CodeGenFunction::InitializeVTablePointer(BaseSubobject Base, + const CXXRecordDecl *NearestVBase, + CharUnits OffsetFromNearestVBase, + const CXXRecordDecl *VTableClass) { + const CXXRecordDecl *RD = Base.getBase(); + + // Don't initialize the vtable pointer if the class is marked with the + // 'novtable' attribute. + if ((RD == VTableClass || RD == NearestVBase) && + VTableClass->hasAttr<MSNoVTableAttr>()) + return; + + // Compute the address point. + bool NeedsVirtualOffset; + llvm::Value *VTableAddressPoint = + CGM.getCXXABI().getVTableAddressPointInStructor( + *this, VTableClass, Base, NearestVBase, NeedsVirtualOffset); + if (!VTableAddressPoint) + return; + + // Compute where to store the address point. + llvm::Value *VirtualOffset = nullptr; + CharUnits NonVirtualOffset = CharUnits::Zero(); + + if (NeedsVirtualOffset) { + // We need to use the virtual base offset offset because the virtual base + // might have a different offset in the most derived class. + VirtualOffset = CGM.getCXXABI().GetVirtualBaseClassOffset(*this, + 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. Use the same LLVM types as the field to + // support optimization. + llvm::Type *VTablePtrTy = + llvm::FunctionType::get(CGM.Int32Ty, /*isVarArg=*/true) + ->getPointerTo() + ->getPointerTo(); + VTableField = Builder.CreateBitCast(VTableField, VTablePtrTy->getPointerTo()); + VTableAddressPoint = Builder.CreateBitCast(VTableAddressPoint, VTablePtrTy); + llvm::StoreInst *Store = Builder.CreateStore(VTableAddressPoint, VTableField); + CGM.DecorateInstruction(Store, CGM.getTBAAInfoForVTablePtr()); +} + +void +CodeGenFunction::InitializeVTablePointers(BaseSubobject Base, + const CXXRecordDecl *NearestVBase, + CharUnits OffsetFromNearestVBase, + bool BaseIsNonVirtualPrimaryBase, + 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, + VTableClass); + } + + const CXXRecordDecl *RD = Base.getBase(); + + // Traverse bases. + for (const auto &I : RD->bases()) { + 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).second) + 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, + VTableClass, VBases); + } +} + +void CodeGenFunction::InitializeVTablePointers(const CXXRecordDecl *RD) { + // Ignore classes without a vtable. + if (!RD->isDynamicClass()) + return; + + // Initialize the vtable pointers for this class and all of its bases. + VisitedVirtualBasesSetTy VBases; + InitializeVTablePointers(BaseSubobject(RD, CharUnits::Zero()), + /*NearestVBase=*/nullptr, + /*OffsetFromNearestVBase=*/CharUnits::Zero(), + /*BaseIsNonVirtualPrimaryBase=*/false, RD, VBases); + + if (RD->getNumVBases()) + CGM.getCXXABI().initializeHiddenVirtualInheritanceMembers(*this, RD); +} + +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; +} + +// If a class has a single non-virtual base and does not introduce or override +// virtual member functions or fields, it will have the same layout as its base. +// This function returns the least derived such class. +// +// Casting an instance of a base class to such a derived class is technically +// undefined behavior, but it is a relatively common hack for introducing member +// functions on class instances with specific properties (e.g. llvm::Operator) +// that works under most compilers and should not have security implications, so +// we allow it by default. It can be disabled with -fsanitize=cfi-cast-strict. +static const CXXRecordDecl * +LeastDerivedClassWithSameLayout(const CXXRecordDecl *RD) { + if (!RD->field_empty()) + return RD; + + if (RD->getNumVBases() != 0) + return RD; + + if (RD->getNumBases() != 1) + return RD; + + for (const CXXMethodDecl *MD : RD->methods()) { + if (MD->isVirtual()) { + // Virtual member functions are only ok if they are implicit destructors + // because the implicit destructor will have the same semantics as the + // base class's destructor if no fields are added. + if (isa<CXXDestructorDecl>(MD) && MD->isImplicit()) + continue; + return RD; + } + } + + return LeastDerivedClassWithSameLayout( + RD->bases_begin()->getType()->getAsCXXRecordDecl()); +} + +void CodeGenFunction::EmitVTablePtrCheckForCall(const CXXMethodDecl *MD, + llvm::Value *VTable, + CFITypeCheckKind TCK, + SourceLocation Loc) { + const CXXRecordDecl *ClassDecl = MD->getParent(); + if (!SanOpts.has(SanitizerKind::CFICastStrict)) + ClassDecl = LeastDerivedClassWithSameLayout(ClassDecl); + + EmitVTablePtrCheck(ClassDecl, VTable, TCK, Loc); +} + +void CodeGenFunction::EmitVTablePtrCheckForCast(QualType T, + llvm::Value *Derived, + bool MayBeNull, + CFITypeCheckKind TCK, + SourceLocation Loc) { + if (!getLangOpts().CPlusPlus) + return; + + auto *ClassTy = T->getAs<RecordType>(); + if (!ClassTy) + return; + + const CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(ClassTy->getDecl()); + + if (!ClassDecl->isCompleteDefinition() || !ClassDecl->isDynamicClass()) + return; + + SmallString<64> MangledName; + llvm::raw_svector_ostream Out(MangledName); + CGM.getCXXABI().getMangleContext().mangleCXXRTTI(T.getUnqualifiedType(), + Out); + + // Blacklist based on the mangled type. + if (CGM.getContext().getSanitizerBlacklist().isBlacklistedType(Out.str())) + return; + + if (!SanOpts.has(SanitizerKind::CFICastStrict)) + ClassDecl = LeastDerivedClassWithSameLayout(ClassDecl); + + llvm::BasicBlock *ContBlock = 0; + + if (MayBeNull) { + llvm::Value *DerivedNotNull = + Builder.CreateIsNotNull(Derived, "cast.nonnull"); + + llvm::BasicBlock *CheckBlock = createBasicBlock("cast.check"); + ContBlock = createBasicBlock("cast.cont"); + + Builder.CreateCondBr(DerivedNotNull, CheckBlock, ContBlock); + + EmitBlock(CheckBlock); + } + + llvm::Value *VTable = GetVTablePtr(Derived, Int8PtrTy); + EmitVTablePtrCheck(ClassDecl, VTable, TCK, Loc); + + if (MayBeNull) { + Builder.CreateBr(ContBlock); + EmitBlock(ContBlock); + } +} + +void CodeGenFunction::EmitVTablePtrCheck(const CXXRecordDecl *RD, + llvm::Value *VTable, + CFITypeCheckKind TCK, + SourceLocation Loc) { + if (CGM.IsCFIBlacklistedRecord(RD)) + return; + + SanitizerScope SanScope(this); + + std::string OutName; + llvm::raw_string_ostream Out(OutName); + CGM.getCXXABI().getMangleContext().mangleCXXVTableBitSet(RD, Out); + + llvm::Value *BitSetName = llvm::MetadataAsValue::get( + getLLVMContext(), llvm::MDString::get(getLLVMContext(), Out.str())); + + llvm::Value *CastedVTable = Builder.CreateBitCast(VTable, Int8PtrTy); + llvm::Value *BitSetTest = + Builder.CreateCall(CGM.getIntrinsic(llvm::Intrinsic::bitset_test), + {CastedVTable, BitSetName}); + + SanitizerMask M; + switch (TCK) { + case CFITCK_VCall: + M = SanitizerKind::CFIVCall; + break; + case CFITCK_NVCall: + M = SanitizerKind::CFINVCall; + break; + case CFITCK_DerivedCast: + M = SanitizerKind::CFIDerivedCast; + break; + case CFITCK_UnrelatedCast: + M = SanitizerKind::CFIUnrelatedCast; + break; + } + + llvm::Constant *StaticData[] = { + EmitCheckSourceLocation(Loc), + EmitCheckTypeDescriptor(QualType(RD->getTypeForDecl(), 0)), + llvm::ConstantInt::get(Int8Ty, TCK), + }; + EmitCheck(std::make_pair(BitSetTest, M), "cfi_bad_type", StaticData, + CastedVTable); +} + +// 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; + } +} + +bool +CodeGenFunction::CanDevirtualizeMemberFunctionCall(const Expr *Base, + const CXXMethodDecl *MD) { + // When building with -fapple-kext, all calls must go through the vtable since + // the kernel linker can do runtime patching of vtables. + if (getLangOpts().AppleKext) + return false; + + // If the most derived class is marked final, we know that no subclass can + // override this member function and so we can devirtualize it. For example: + // + // struct A { virtual void f(); } + // struct B final : A { }; + // + // void f(B *b) { + // b->f(); + // } + // + const CXXRecordDecl *MostDerivedClassDecl = Base->getBestDynamicClassType(); + 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 devirtualize calls on an object accessed by a class member access + // expression, since by C++11 [basic.life]p6 we know that it can't refer to + // a derived class object constructed in the same location. + if (const MemberExpr *ME = dyn_cast<MemberExpr>(Base)) + if (const ValueDecl *VD = dyn_cast<ValueDecl>(ME->getMemberDecl())) + return VD->getType()->isRecordType(); + + // 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(getContext())->isRecordType(); + + // We can't devirtualize the call. + return false; +} + +void CodeGenFunction::EmitForwardingCallToLambda( + const CXXMethodDecl *callOperator, + CallArgList &callArgs) { + // 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->getReturnType(); + ReturnValueSlot returnSlot; + if (!resultType->isVoidType() && + calleeFnInfo.getReturnInfo().getKind() == ABIArgInfo::Indirect && + !hasScalarEvaluationKind(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 (auto param : BD->params()) + EmitDelegateCallArg(CallArgs, param, param->getLocStart()); + + assert(!Lambda->isGenericLambda() && + "generic lambda interconversion to block not implemented"); + EmitForwardingCallToLambda(Lambda->getLambdaCallOperator(), CallArgs); +} + +void CodeGenFunction::EmitLambdaToBlockPointerBody(FunctionArgList &Args) { + if (cast<CXXMethodDecl>(CurCodeDecl)->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(CurCodeDecl, "lambda conversion to variadic function"); + return; + } + + EmitFunctionBody(Args, cast<FunctionDecl>(CurGD.getDecl())->getBody()); +} + +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 (auto Param : MD->params()) + EmitDelegateCallArg(CallArgs, Param, Param->getLocStart()); + + const CXXMethodDecl *CallOp = Lambda->getLambdaCallOperator(); + // For a generic lambda, find the corresponding call operator specialization + // to which the call to the static-invoker shall be forwarded. + if (Lambda->isGenericLambda()) { + assert(MD->isFunctionTemplateSpecialization()); + const TemplateArgumentList *TAL = MD->getTemplateSpecializationArgs(); + FunctionTemplateDecl *CallOpTemplate = CallOp->getDescribedFunctionTemplate(); + void *InsertPos = nullptr; + FunctionDecl *CorrespondingCallOpSpecialization = + CallOpTemplate->findSpecialization(TAL->asArray(), InsertPos); + assert(CorrespondingCallOpSpecialization); + CallOp = cast<CXXMethodDecl>(CorrespondingCallOpSpecialization); + } + EmitForwardingCallToLambda(CallOp, 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); +} |
