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Diffstat (limited to 'contrib/llvm/tools/clang/lib/CodeGen/MicrosoftCXXABI.cpp')
| -rw-r--r-- | contrib/llvm/tools/clang/lib/CodeGen/MicrosoftCXXABI.cpp | 4175 |
1 files changed, 4175 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/CodeGen/MicrosoftCXXABI.cpp b/contrib/llvm/tools/clang/lib/CodeGen/MicrosoftCXXABI.cpp new file mode 100644 index 0000000..93210d5 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/CodeGen/MicrosoftCXXABI.cpp @@ -0,0 +1,4175 @@ +//===--- MicrosoftCXXABI.cpp - Emit LLVM Code from ASTs for a Module ------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This provides C++ code generation targeting the Microsoft Visual C++ ABI. +// The class in this file generates structures that follow the Microsoft +// Visual C++ ABI, which is actually not very well documented at all outside +// of Microsoft. +// +//===----------------------------------------------------------------------===// + +#include "CGCXXABI.h" +#include "CGCleanup.h" +#include "CGVTables.h" +#include "CodeGenModule.h" +#include "CodeGenTypes.h" +#include "TargetInfo.h" +#include "clang/AST/Decl.h" +#include "clang/AST/DeclCXX.h" +#include "clang/AST/StmtCXX.h" +#include "clang/AST/VTableBuilder.h" +#include "llvm/ADT/StringExtras.h" +#include "llvm/ADT/StringSet.h" +#include "llvm/IR/CallSite.h" +#include "llvm/IR/Intrinsics.h" + +using namespace clang; +using namespace CodeGen; + +namespace { + +/// Holds all the vbtable globals for a given class. +struct VBTableGlobals { + const VPtrInfoVector *VBTables; + SmallVector<llvm::GlobalVariable *, 2> Globals; +}; + +class MicrosoftCXXABI : public CGCXXABI { +public: + MicrosoftCXXABI(CodeGenModule &CGM) + : CGCXXABI(CGM), BaseClassDescriptorType(nullptr), + ClassHierarchyDescriptorType(nullptr), + CompleteObjectLocatorType(nullptr), CatchableTypeType(nullptr), + ThrowInfoType(nullptr) {} + + bool HasThisReturn(GlobalDecl GD) const override; + bool hasMostDerivedReturn(GlobalDecl GD) const override; + + bool classifyReturnType(CGFunctionInfo &FI) const override; + + RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const override; + + bool isSRetParameterAfterThis() const override { return true; } + + bool isThisCompleteObject(GlobalDecl GD) const override { + // The Microsoft ABI doesn't use separate complete-object vs. + // base-object variants of constructors, but it does of destructors. + if (isa<CXXDestructorDecl>(GD.getDecl())) { + switch (GD.getDtorType()) { + case Dtor_Complete: + case Dtor_Deleting: + return true; + + case Dtor_Base: + return false; + + case Dtor_Comdat: llvm_unreachable("emitting dtor comdat as function?"); + } + llvm_unreachable("bad dtor kind"); + } + + // No other kinds. + return false; + } + + size_t getSrcArgforCopyCtor(const CXXConstructorDecl *CD, + FunctionArgList &Args) const override { + assert(Args.size() >= 2 && + "expected the arglist to have at least two args!"); + // The 'most_derived' parameter goes second if the ctor is variadic and + // has v-bases. + if (CD->getParent()->getNumVBases() > 0 && + CD->getType()->castAs<FunctionProtoType>()->isVariadic()) + return 2; + return 1; + } + + std::vector<CharUnits> getVBPtrOffsets(const CXXRecordDecl *RD) override { + std::vector<CharUnits> VBPtrOffsets; + const ASTContext &Context = getContext(); + const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD); + + const VBTableGlobals &VBGlobals = enumerateVBTables(RD); + for (const VPtrInfo *VBT : *VBGlobals.VBTables) { + const ASTRecordLayout &SubobjectLayout = + Context.getASTRecordLayout(VBT->BaseWithVPtr); + CharUnits Offs = VBT->NonVirtualOffset; + Offs += SubobjectLayout.getVBPtrOffset(); + if (VBT->getVBaseWithVPtr()) + Offs += Layout.getVBaseClassOffset(VBT->getVBaseWithVPtr()); + VBPtrOffsets.push_back(Offs); + } + llvm::array_pod_sort(VBPtrOffsets.begin(), VBPtrOffsets.end()); + return VBPtrOffsets; + } + + StringRef GetPureVirtualCallName() override { return "_purecall"; } + StringRef GetDeletedVirtualCallName() override { return "_purecall"; } + + void emitVirtualObjectDelete(CodeGenFunction &CGF, const CXXDeleteExpr *DE, + Address Ptr, QualType ElementType, + const CXXDestructorDecl *Dtor) override; + + void emitRethrow(CodeGenFunction &CGF, bool isNoReturn) override; + void emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) override; + + void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) override; + + llvm::GlobalVariable *getMSCompleteObjectLocator(const CXXRecordDecl *RD, + const VPtrInfo *Info); + + llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) override; + CatchTypeInfo + getAddrOfCXXCatchHandlerType(QualType Ty, QualType CatchHandlerType) override; + + /// MSVC needs an extra flag to indicate a catchall. + CatchTypeInfo getCatchAllTypeInfo() override { + return CatchTypeInfo{nullptr, 0x40}; + } + + bool shouldTypeidBeNullChecked(bool IsDeref, QualType SrcRecordTy) override; + void EmitBadTypeidCall(CodeGenFunction &CGF) override; + llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy, + Address ThisPtr, + llvm::Type *StdTypeInfoPtrTy) override; + + bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr, + QualType SrcRecordTy) override; + + llvm::Value *EmitDynamicCastCall(CodeGenFunction &CGF, Address Value, + QualType SrcRecordTy, QualType DestTy, + QualType DestRecordTy, + llvm::BasicBlock *CastEnd) override; + + llvm::Value *EmitDynamicCastToVoid(CodeGenFunction &CGF, Address Value, + QualType SrcRecordTy, + QualType DestTy) override; + + bool EmitBadCastCall(CodeGenFunction &CGF) override; + bool canSpeculativelyEmitVTable(const CXXRecordDecl *RD) const override { + return false; + } + + llvm::Value * + GetVirtualBaseClassOffset(CodeGenFunction &CGF, Address This, + const CXXRecordDecl *ClassDecl, + const CXXRecordDecl *BaseClassDecl) override; + + llvm::BasicBlock * + EmitCtorCompleteObjectHandler(CodeGenFunction &CGF, + const CXXRecordDecl *RD) override; + + void initializeHiddenVirtualInheritanceMembers(CodeGenFunction &CGF, + const CXXRecordDecl *RD) override; + + void EmitCXXConstructors(const CXXConstructorDecl *D) override; + + // Background on MSVC destructors + // ============================== + // + // Both Itanium and MSVC ABIs have destructor variants. The variant names + // roughly correspond in the following way: + // Itanium Microsoft + // Base -> no name, just ~Class + // Complete -> vbase destructor + // Deleting -> scalar deleting destructor + // vector deleting destructor + // + // The base and complete destructors are the same as in Itanium, although the + // complete destructor does not accept a VTT parameter when there are virtual + // bases. A separate mechanism involving vtordisps is used to ensure that + // virtual methods of destroyed subobjects are not called. + // + // The deleting destructors accept an i32 bitfield as a second parameter. Bit + // 1 indicates if the memory should be deleted. Bit 2 indicates if the this + // pointer points to an array. The scalar deleting destructor assumes that + // bit 2 is zero, and therefore does not contain a loop. + // + // For virtual destructors, only one entry is reserved in the vftable, and it + // always points to the vector deleting destructor. The vector deleting + // destructor is the most general, so it can be used to destroy objects in + // place, delete single heap objects, or delete arrays. + // + // A TU defining a non-inline destructor is only guaranteed to emit a base + // destructor, and all of the other variants are emitted on an as-needed basis + // in COMDATs. Because a non-base destructor can be emitted in a TU that + // lacks a definition for the destructor, non-base destructors must always + // delegate to or alias the base destructor. + + void buildStructorSignature(const CXXMethodDecl *MD, StructorType T, + SmallVectorImpl<CanQualType> &ArgTys) override; + + /// Non-base dtors should be emitted as delegating thunks in this ABI. + bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor, + CXXDtorType DT) const override { + return DT != Dtor_Base; + } + + void EmitCXXDestructors(const CXXDestructorDecl *D) override; + + const CXXRecordDecl * + getThisArgumentTypeForMethod(const CXXMethodDecl *MD) override { + MD = MD->getCanonicalDecl(); + if (MD->isVirtual() && !isa<CXXDestructorDecl>(MD)) { + MicrosoftVTableContext::MethodVFTableLocation ML = + CGM.getMicrosoftVTableContext().getMethodVFTableLocation(MD); + // The vbases might be ordered differently in the final overrider object + // and the complete object, so the "this" argument may sometimes point to + // memory that has no particular type (e.g. past the complete object). + // In this case, we just use a generic pointer type. + // FIXME: might want to have a more precise type in the non-virtual + // multiple inheritance case. + if (ML.VBase || !ML.VFPtrOffset.isZero()) + return nullptr; + } + return MD->getParent(); + } + + Address + adjustThisArgumentForVirtualFunctionCall(CodeGenFunction &CGF, GlobalDecl GD, + Address This, + bool VirtualCall) override; + + void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy, + FunctionArgList &Params) override; + + llvm::Value *adjustThisParameterInVirtualFunctionPrologue( + CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) override; + + void EmitInstanceFunctionProlog(CodeGenFunction &CGF) override; + + unsigned addImplicitConstructorArgs(CodeGenFunction &CGF, + const CXXConstructorDecl *D, + CXXCtorType Type, bool ForVirtualBase, + bool Delegating, + CallArgList &Args) override; + + void EmitDestructorCall(CodeGenFunction &CGF, const CXXDestructorDecl *DD, + CXXDtorType Type, bool ForVirtualBase, + bool Delegating, Address This) override; + + void emitVTableBitSetEntries(VPtrInfo *Info, const CXXRecordDecl *RD, + llvm::GlobalVariable *VTable); + + void emitVTableDefinitions(CodeGenVTables &CGVT, + const CXXRecordDecl *RD) override; + + bool isVirtualOffsetNeededForVTableField(CodeGenFunction &CGF, + CodeGenFunction::VPtr Vptr) override; + + /// Don't initialize vptrs if dynamic class + /// is marked with with the 'novtable' attribute. + bool doStructorsInitializeVPtrs(const CXXRecordDecl *VTableClass) override { + return !VTableClass->hasAttr<MSNoVTableAttr>(); + } + + llvm::Constant * + getVTableAddressPoint(BaseSubobject Base, + const CXXRecordDecl *VTableClass) override; + + llvm::Value *getVTableAddressPointInStructor( + CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, + BaseSubobject Base, const CXXRecordDecl *NearestVBase) override; + + llvm::Constant * + getVTableAddressPointForConstExpr(BaseSubobject Base, + const CXXRecordDecl *VTableClass) override; + + llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD, + CharUnits VPtrOffset) override; + + llvm::Value *getVirtualFunctionPointer(CodeGenFunction &CGF, GlobalDecl GD, + Address This, llvm::Type *Ty, + SourceLocation Loc) override; + + llvm::Value *EmitVirtualDestructorCall(CodeGenFunction &CGF, + const CXXDestructorDecl *Dtor, + CXXDtorType DtorType, + Address This, + const CXXMemberCallExpr *CE) override; + + void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF, GlobalDecl GD, + CallArgList &CallArgs) override { + assert(GD.getDtorType() == Dtor_Deleting && + "Only deleting destructor thunks are available in this ABI"); + CallArgs.add(RValue::get(getStructorImplicitParamValue(CGF)), + getContext().IntTy); + } + + void emitVirtualInheritanceTables(const CXXRecordDecl *RD) override; + + llvm::GlobalVariable * + getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD, + llvm::GlobalVariable::LinkageTypes Linkage); + + llvm::GlobalVariable * + getAddrOfVirtualDisplacementMap(const CXXRecordDecl *SrcRD, + const CXXRecordDecl *DstRD) { + SmallString<256> OutName; + llvm::raw_svector_ostream Out(OutName); + getMangleContext().mangleCXXVirtualDisplacementMap(SrcRD, DstRD, Out); + StringRef MangledName = OutName.str(); + + if (auto *VDispMap = CGM.getModule().getNamedGlobal(MangledName)) + return VDispMap; + + MicrosoftVTableContext &VTContext = CGM.getMicrosoftVTableContext(); + unsigned NumEntries = 1 + SrcRD->getNumVBases(); + SmallVector<llvm::Constant *, 4> Map(NumEntries, + llvm::UndefValue::get(CGM.IntTy)); + Map[0] = llvm::ConstantInt::get(CGM.IntTy, 0); + bool AnyDifferent = false; + for (const auto &I : SrcRD->vbases()) { + const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl(); + if (!DstRD->isVirtuallyDerivedFrom(VBase)) + continue; + + unsigned SrcVBIndex = VTContext.getVBTableIndex(SrcRD, VBase); + unsigned DstVBIndex = VTContext.getVBTableIndex(DstRD, VBase); + Map[SrcVBIndex] = llvm::ConstantInt::get(CGM.IntTy, DstVBIndex * 4); + AnyDifferent |= SrcVBIndex != DstVBIndex; + } + // This map would be useless, don't use it. + if (!AnyDifferent) + return nullptr; + + llvm::ArrayType *VDispMapTy = llvm::ArrayType::get(CGM.IntTy, Map.size()); + llvm::Constant *Init = llvm::ConstantArray::get(VDispMapTy, Map); + llvm::GlobalValue::LinkageTypes Linkage = + SrcRD->isExternallyVisible() && DstRD->isExternallyVisible() + ? llvm::GlobalValue::LinkOnceODRLinkage + : llvm::GlobalValue::InternalLinkage; + auto *VDispMap = new llvm::GlobalVariable( + CGM.getModule(), VDispMapTy, /*Constant=*/true, Linkage, + /*Initializer=*/Init, MangledName); + return VDispMap; + } + + void emitVBTableDefinition(const VPtrInfo &VBT, const CXXRecordDecl *RD, + llvm::GlobalVariable *GV) const; + + void setThunkLinkage(llvm::Function *Thunk, bool ForVTable, + GlobalDecl GD, bool ReturnAdjustment) override { + // Never dllimport/dllexport thunks. + Thunk->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass); + + GVALinkage Linkage = + getContext().GetGVALinkageForFunction(cast<FunctionDecl>(GD.getDecl())); + + if (Linkage == GVA_Internal) + Thunk->setLinkage(llvm::GlobalValue::InternalLinkage); + else if (ReturnAdjustment) + Thunk->setLinkage(llvm::GlobalValue::WeakODRLinkage); + else + Thunk->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage); + } + + llvm::Value *performThisAdjustment(CodeGenFunction &CGF, Address This, + const ThisAdjustment &TA) override; + + llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, Address Ret, + const ReturnAdjustment &RA) override; + + void EmitThreadLocalInitFuncs( + CodeGenModule &CGM, ArrayRef<const VarDecl *> CXXThreadLocals, + ArrayRef<llvm::Function *> CXXThreadLocalInits, + ArrayRef<const VarDecl *> CXXThreadLocalInitVars) override; + + bool usesThreadWrapperFunction() const override { return false; } + LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, const VarDecl *VD, + QualType LValType) override; + + void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D, + llvm::GlobalVariable *DeclPtr, + bool PerformInit) override; + void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D, + llvm::Constant *Dtor, llvm::Constant *Addr) override; + + // ==== Notes on array cookies ========= + // + // MSVC seems to only use cookies when the class has a destructor; a + // two-argument usual array deallocation function isn't sufficient. + // + // For example, this code prints "100" and "1": + // struct A { + // char x; + // void *operator new[](size_t sz) { + // printf("%u\n", sz); + // return malloc(sz); + // } + // void operator delete[](void *p, size_t sz) { + // printf("%u\n", sz); + // free(p); + // } + // }; + // int main() { + // A *p = new A[100]; + // delete[] p; + // } + // Whereas it prints "104" and "104" if you give A a destructor. + + bool requiresArrayCookie(const CXXDeleteExpr *expr, + QualType elementType) override; + bool requiresArrayCookie(const CXXNewExpr *expr) override; + CharUnits getArrayCookieSizeImpl(QualType type) override; + Address InitializeArrayCookie(CodeGenFunction &CGF, + Address NewPtr, + llvm::Value *NumElements, + const CXXNewExpr *expr, + QualType ElementType) override; + llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF, + Address allocPtr, + CharUnits cookieSize) override; + + friend struct MSRTTIBuilder; + + bool isImageRelative() const { + return CGM.getTarget().getPointerWidth(/*AddressSpace=*/0) == 64; + } + + // 5 routines for constructing the llvm types for MS RTTI structs. + llvm::StructType *getTypeDescriptorType(StringRef TypeInfoString) { + llvm::SmallString<32> TDTypeName("rtti.TypeDescriptor"); + TDTypeName += llvm::utostr(TypeInfoString.size()); + llvm::StructType *&TypeDescriptorType = + TypeDescriptorTypeMap[TypeInfoString.size()]; + if (TypeDescriptorType) + return TypeDescriptorType; + llvm::Type *FieldTypes[] = { + CGM.Int8PtrPtrTy, + CGM.Int8PtrTy, + llvm::ArrayType::get(CGM.Int8Ty, TypeInfoString.size() + 1)}; + TypeDescriptorType = + llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, TDTypeName); + return TypeDescriptorType; + } + + llvm::Type *getImageRelativeType(llvm::Type *PtrType) { + if (!isImageRelative()) + return PtrType; + return CGM.IntTy; + } + + llvm::StructType *getBaseClassDescriptorType() { + if (BaseClassDescriptorType) + return BaseClassDescriptorType; + llvm::Type *FieldTypes[] = { + getImageRelativeType(CGM.Int8PtrTy), + CGM.IntTy, + CGM.IntTy, + CGM.IntTy, + CGM.IntTy, + CGM.IntTy, + getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()), + }; + BaseClassDescriptorType = llvm::StructType::create( + CGM.getLLVMContext(), FieldTypes, "rtti.BaseClassDescriptor"); + return BaseClassDescriptorType; + } + + llvm::StructType *getClassHierarchyDescriptorType() { + if (ClassHierarchyDescriptorType) + return ClassHierarchyDescriptorType; + // Forward-declare RTTIClassHierarchyDescriptor to break a cycle. + ClassHierarchyDescriptorType = llvm::StructType::create( + CGM.getLLVMContext(), "rtti.ClassHierarchyDescriptor"); + llvm::Type *FieldTypes[] = { + CGM.IntTy, + CGM.IntTy, + CGM.IntTy, + getImageRelativeType( + getBaseClassDescriptorType()->getPointerTo()->getPointerTo()), + }; + ClassHierarchyDescriptorType->setBody(FieldTypes); + return ClassHierarchyDescriptorType; + } + + llvm::StructType *getCompleteObjectLocatorType() { + if (CompleteObjectLocatorType) + return CompleteObjectLocatorType; + CompleteObjectLocatorType = llvm::StructType::create( + CGM.getLLVMContext(), "rtti.CompleteObjectLocator"); + llvm::Type *FieldTypes[] = { + CGM.IntTy, + CGM.IntTy, + CGM.IntTy, + getImageRelativeType(CGM.Int8PtrTy), + getImageRelativeType(getClassHierarchyDescriptorType()->getPointerTo()), + getImageRelativeType(CompleteObjectLocatorType), + }; + llvm::ArrayRef<llvm::Type *> FieldTypesRef(FieldTypes); + if (!isImageRelative()) + FieldTypesRef = FieldTypesRef.drop_back(); + CompleteObjectLocatorType->setBody(FieldTypesRef); + return CompleteObjectLocatorType; + } + + llvm::GlobalVariable *getImageBase() { + StringRef Name = "__ImageBase"; + if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(Name)) + return GV; + + return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8Ty, + /*isConstant=*/true, + llvm::GlobalValue::ExternalLinkage, + /*Initializer=*/nullptr, Name); + } + + llvm::Constant *getImageRelativeConstant(llvm::Constant *PtrVal) { + if (!isImageRelative()) + return PtrVal; + + if (PtrVal->isNullValue()) + return llvm::Constant::getNullValue(CGM.IntTy); + + llvm::Constant *ImageBaseAsInt = + llvm::ConstantExpr::getPtrToInt(getImageBase(), CGM.IntPtrTy); + llvm::Constant *PtrValAsInt = + llvm::ConstantExpr::getPtrToInt(PtrVal, CGM.IntPtrTy); + llvm::Constant *Diff = + llvm::ConstantExpr::getSub(PtrValAsInt, ImageBaseAsInt, + /*HasNUW=*/true, /*HasNSW=*/true); + return llvm::ConstantExpr::getTrunc(Diff, CGM.IntTy); + } + +private: + MicrosoftMangleContext &getMangleContext() { + return cast<MicrosoftMangleContext>(CodeGen::CGCXXABI::getMangleContext()); + } + + llvm::Constant *getZeroInt() { + return llvm::ConstantInt::get(CGM.IntTy, 0); + } + + llvm::Constant *getAllOnesInt() { + return llvm::Constant::getAllOnesValue(CGM.IntTy); + } + + CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD); + + void + GetNullMemberPointerFields(const MemberPointerType *MPT, + llvm::SmallVectorImpl<llvm::Constant *> &fields); + + /// \brief Shared code for virtual base adjustment. Returns the offset from + /// the vbptr to the virtual base. Optionally returns the address of the + /// vbptr itself. + llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF, + Address Base, + llvm::Value *VBPtrOffset, + llvm::Value *VBTableOffset, + llvm::Value **VBPtr = nullptr); + + llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF, + Address Base, + int32_t VBPtrOffset, + int32_t VBTableOffset, + llvm::Value **VBPtr = nullptr) { + assert(VBTableOffset % 4 == 0 && "should be byte offset into table of i32s"); + llvm::Value *VBPOffset = llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset), + *VBTOffset = llvm::ConstantInt::get(CGM.IntTy, VBTableOffset); + return GetVBaseOffsetFromVBPtr(CGF, Base, VBPOffset, VBTOffset, VBPtr); + } + + std::pair<Address, llvm::Value *> + performBaseAdjustment(CodeGenFunction &CGF, Address Value, + QualType SrcRecordTy); + + /// \brief Performs a full virtual base adjustment. Used to dereference + /// pointers to members of virtual bases. + llvm::Value *AdjustVirtualBase(CodeGenFunction &CGF, const Expr *E, + const CXXRecordDecl *RD, Address Base, + llvm::Value *VirtualBaseAdjustmentOffset, + llvm::Value *VBPtrOffset /* optional */); + + /// \brief Emits a full member pointer with the fields common to data and + /// function member pointers. + llvm::Constant *EmitFullMemberPointer(llvm::Constant *FirstField, + bool IsMemberFunction, + const CXXRecordDecl *RD, + CharUnits NonVirtualBaseAdjustment, + unsigned VBTableIndex); + + bool MemberPointerConstantIsNull(const MemberPointerType *MPT, + llvm::Constant *MP); + + /// \brief - Initialize all vbptrs of 'this' with RD as the complete type. + void EmitVBPtrStores(CodeGenFunction &CGF, const CXXRecordDecl *RD); + + /// \brief Caching wrapper around VBTableBuilder::enumerateVBTables(). + const VBTableGlobals &enumerateVBTables(const CXXRecordDecl *RD); + + /// \brief Generate a thunk for calling a virtual member function MD. + llvm::Function *EmitVirtualMemPtrThunk( + const CXXMethodDecl *MD, + const MicrosoftVTableContext::MethodVFTableLocation &ML); + +public: + llvm::Type *ConvertMemberPointerType(const MemberPointerType *MPT) override; + + bool isZeroInitializable(const MemberPointerType *MPT) override; + + bool isMemberPointerConvertible(const MemberPointerType *MPT) const override { + const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl(); + return RD->hasAttr<MSInheritanceAttr>(); + } + + llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT) override; + + llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT, + CharUnits offset) override; + llvm::Constant *EmitMemberFunctionPointer(const CXXMethodDecl *MD) override; + llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT) override; + + llvm::Value *EmitMemberPointerComparison(CodeGenFunction &CGF, + llvm::Value *L, + llvm::Value *R, + const MemberPointerType *MPT, + bool Inequality) override; + + llvm::Value *EmitMemberPointerIsNotNull(CodeGenFunction &CGF, + llvm::Value *MemPtr, + const MemberPointerType *MPT) override; + + llvm::Value * + EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E, + Address Base, llvm::Value *MemPtr, + const MemberPointerType *MPT) override; + + llvm::Value *EmitNonNullMemberPointerConversion( + const MemberPointerType *SrcTy, const MemberPointerType *DstTy, + CastKind CK, CastExpr::path_const_iterator PathBegin, + CastExpr::path_const_iterator PathEnd, llvm::Value *Src, + CGBuilderTy &Builder); + + llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF, + const CastExpr *E, + llvm::Value *Src) override; + + llvm::Constant *EmitMemberPointerConversion(const CastExpr *E, + llvm::Constant *Src) override; + + llvm::Constant *EmitMemberPointerConversion( + const MemberPointerType *SrcTy, const MemberPointerType *DstTy, + CastKind CK, CastExpr::path_const_iterator PathBegin, + CastExpr::path_const_iterator PathEnd, llvm::Constant *Src); + + llvm::Value * + EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, const Expr *E, + Address This, llvm::Value *&ThisPtrForCall, + llvm::Value *MemPtr, + const MemberPointerType *MPT) override; + + void emitCXXStructor(const CXXMethodDecl *MD, StructorType Type) override; + + llvm::StructType *getCatchableTypeType() { + if (CatchableTypeType) + return CatchableTypeType; + llvm::Type *FieldTypes[] = { + CGM.IntTy, // Flags + getImageRelativeType(CGM.Int8PtrTy), // TypeDescriptor + CGM.IntTy, // NonVirtualAdjustment + CGM.IntTy, // OffsetToVBPtr + CGM.IntTy, // VBTableIndex + CGM.IntTy, // Size + getImageRelativeType(CGM.Int8PtrTy) // CopyCtor + }; + CatchableTypeType = llvm::StructType::create( + CGM.getLLVMContext(), FieldTypes, "eh.CatchableType"); + return CatchableTypeType; + } + + llvm::StructType *getCatchableTypeArrayType(uint32_t NumEntries) { + llvm::StructType *&CatchableTypeArrayType = + CatchableTypeArrayTypeMap[NumEntries]; + if (CatchableTypeArrayType) + return CatchableTypeArrayType; + + llvm::SmallString<23> CTATypeName("eh.CatchableTypeArray."); + CTATypeName += llvm::utostr(NumEntries); + llvm::Type *CTType = + getImageRelativeType(getCatchableTypeType()->getPointerTo()); + llvm::Type *FieldTypes[] = { + CGM.IntTy, // NumEntries + llvm::ArrayType::get(CTType, NumEntries) // CatchableTypes + }; + CatchableTypeArrayType = + llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, CTATypeName); + return CatchableTypeArrayType; + } + + llvm::StructType *getThrowInfoType() { + if (ThrowInfoType) + return ThrowInfoType; + llvm::Type *FieldTypes[] = { + CGM.IntTy, // Flags + getImageRelativeType(CGM.Int8PtrTy), // CleanupFn + getImageRelativeType(CGM.Int8PtrTy), // ForwardCompat + getImageRelativeType(CGM.Int8PtrTy) // CatchableTypeArray + }; + ThrowInfoType = llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, + "eh.ThrowInfo"); + return ThrowInfoType; + } + + llvm::Constant *getThrowFn() { + // _CxxThrowException is passed an exception object and a ThrowInfo object + // which describes the exception. + llvm::Type *Args[] = {CGM.Int8PtrTy, getThrowInfoType()->getPointerTo()}; + llvm::FunctionType *FTy = + llvm::FunctionType::get(CGM.VoidTy, Args, /*IsVarArgs=*/false); + auto *Fn = cast<llvm::Function>( + CGM.CreateRuntimeFunction(FTy, "_CxxThrowException")); + // _CxxThrowException is stdcall on 32-bit x86 platforms. + if (CGM.getTarget().getTriple().getArch() == llvm::Triple::x86) + Fn->setCallingConv(llvm::CallingConv::X86_StdCall); + return Fn; + } + + llvm::Function *getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD, + CXXCtorType CT); + + llvm::Constant *getCatchableType(QualType T, + uint32_t NVOffset = 0, + int32_t VBPtrOffset = -1, + uint32_t VBIndex = 0); + + llvm::GlobalVariable *getCatchableTypeArray(QualType T); + + llvm::GlobalVariable *getThrowInfo(QualType T) override; + +private: + typedef std::pair<const CXXRecordDecl *, CharUnits> VFTableIdTy; + typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalVariable *> VTablesMapTy; + typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalValue *> VFTablesMapTy; + /// \brief All the vftables that have been referenced. + VFTablesMapTy VFTablesMap; + VTablesMapTy VTablesMap; + + /// \brief This set holds the record decls we've deferred vtable emission for. + llvm::SmallPtrSet<const CXXRecordDecl *, 4> DeferredVFTables; + + + /// \brief All the vbtables which have been referenced. + llvm::DenseMap<const CXXRecordDecl *, VBTableGlobals> VBTablesMap; + + /// Info on the global variable used to guard initialization of static locals. + /// The BitIndex field is only used for externally invisible declarations. + struct GuardInfo { + GuardInfo() : Guard(nullptr), BitIndex(0) {} + llvm::GlobalVariable *Guard; + unsigned BitIndex; + }; + + /// Map from DeclContext to the current guard variable. We assume that the + /// AST is visited in source code order. + llvm::DenseMap<const DeclContext *, GuardInfo> GuardVariableMap; + llvm::DenseMap<const DeclContext *, GuardInfo> ThreadLocalGuardVariableMap; + llvm::DenseMap<const DeclContext *, unsigned> ThreadSafeGuardNumMap; + + llvm::DenseMap<size_t, llvm::StructType *> TypeDescriptorTypeMap; + llvm::StructType *BaseClassDescriptorType; + llvm::StructType *ClassHierarchyDescriptorType; + llvm::StructType *CompleteObjectLocatorType; + + llvm::DenseMap<QualType, llvm::GlobalVariable *> CatchableTypeArrays; + + llvm::StructType *CatchableTypeType; + llvm::DenseMap<uint32_t, llvm::StructType *> CatchableTypeArrayTypeMap; + llvm::StructType *ThrowInfoType; +}; + +} + +CGCXXABI::RecordArgABI +MicrosoftCXXABI::getRecordArgABI(const CXXRecordDecl *RD) const { + switch (CGM.getTarget().getTriple().getArch()) { + default: + // FIXME: Implement for other architectures. + return RAA_Default; + + case llvm::Triple::x86: + // All record arguments are passed in memory on x86. Decide whether to + // construct the object directly in argument memory, or to construct the + // argument elsewhere and copy the bytes during the call. + + // If C++ prohibits us from making a copy, construct the arguments directly + // into argument memory. + if (!canCopyArgument(RD)) + return RAA_DirectInMemory; + + // Otherwise, construct the argument into a temporary and copy the bytes + // into the outgoing argument memory. + return RAA_Default; + + case llvm::Triple::x86_64: + // Win64 passes objects with non-trivial copy ctors indirectly. + if (RD->hasNonTrivialCopyConstructor()) + return RAA_Indirect; + + // If an object has a destructor, we'd really like to pass it indirectly + // because it allows us to elide copies. Unfortunately, MSVC makes that + // impossible for small types, which it will pass in a single register or + // stack slot. Most objects with dtors are large-ish, so handle that early. + // We can't call out all large objects as being indirect because there are + // multiple x64 calling conventions and the C++ ABI code shouldn't dictate + // how we pass large POD types. + if (RD->hasNonTrivialDestructor() && + getContext().getTypeSize(RD->getTypeForDecl()) > 64) + return RAA_Indirect; + + // We have a trivial copy constructor or no copy constructors, but we have + // to make sure it isn't deleted. + bool CopyDeleted = false; + for (const CXXConstructorDecl *CD : RD->ctors()) { + if (CD->isCopyConstructor()) { + assert(CD->isTrivial()); + // We had at least one undeleted trivial copy ctor. Return directly. + if (!CD->isDeleted()) + return RAA_Default; + CopyDeleted = true; + } + } + + // The trivial copy constructor was deleted. Return indirectly. + if (CopyDeleted) + return RAA_Indirect; + + // There were no copy ctors. Return in RAX. + return RAA_Default; + } + + llvm_unreachable("invalid enum"); +} + +void MicrosoftCXXABI::emitVirtualObjectDelete(CodeGenFunction &CGF, + const CXXDeleteExpr *DE, + Address Ptr, + QualType ElementType, + const CXXDestructorDecl *Dtor) { + // FIXME: Provide a source location here even though there's no + // CXXMemberCallExpr for dtor call. + bool UseGlobalDelete = DE->isGlobalDelete(); + CXXDtorType DtorType = UseGlobalDelete ? Dtor_Complete : Dtor_Deleting; + llvm::Value *MDThis = + EmitVirtualDestructorCall(CGF, Dtor, DtorType, Ptr, /*CE=*/nullptr); + if (UseGlobalDelete) + CGF.EmitDeleteCall(DE->getOperatorDelete(), MDThis, ElementType); +} + +void MicrosoftCXXABI::emitRethrow(CodeGenFunction &CGF, bool isNoReturn) { + llvm::Value *Args[] = { + llvm::ConstantPointerNull::get(CGM.Int8PtrTy), + llvm::ConstantPointerNull::get(getThrowInfoType()->getPointerTo())}; + auto *Fn = getThrowFn(); + if (isNoReturn) + CGF.EmitNoreturnRuntimeCallOrInvoke(Fn, Args); + else + CGF.EmitRuntimeCallOrInvoke(Fn, Args); +} + +namespace { +struct CatchRetScope final : EHScopeStack::Cleanup { + llvm::CatchPadInst *CPI; + + CatchRetScope(llvm::CatchPadInst *CPI) : CPI(CPI) {} + + void Emit(CodeGenFunction &CGF, Flags flags) override { + llvm::BasicBlock *BB = CGF.createBasicBlock("catchret.dest"); + CGF.Builder.CreateCatchRet(CPI, BB); + CGF.EmitBlock(BB); + } +}; +} + +void MicrosoftCXXABI::emitBeginCatch(CodeGenFunction &CGF, + const CXXCatchStmt *S) { + // In the MS ABI, the runtime handles the copy, and the catch handler is + // responsible for destruction. + VarDecl *CatchParam = S->getExceptionDecl(); + llvm::BasicBlock *CatchPadBB = CGF.Builder.GetInsertBlock(); + llvm::CatchPadInst *CPI = + cast<llvm::CatchPadInst>(CatchPadBB->getFirstNonPHI()); + CGF.CurrentFuncletPad = CPI; + + // If this is a catch-all or the catch parameter is unnamed, we don't need to + // emit an alloca to the object. + if (!CatchParam || !CatchParam->getDeclName()) { + CGF.EHStack.pushCleanup<CatchRetScope>(NormalCleanup, CPI); + return; + } + + CodeGenFunction::AutoVarEmission var = CGF.EmitAutoVarAlloca(*CatchParam); + CPI->setArgOperand(2, var.getObjectAddress(CGF).getPointer()); + CGF.EHStack.pushCleanup<CatchRetScope>(NormalCleanup, CPI); + CGF.EmitAutoVarCleanups(var); +} + +/// We need to perform a generic polymorphic operation (like a typeid +/// or a cast), which requires an object with a vfptr. Adjust the +/// address to point to an object with a vfptr. +std::pair<Address, llvm::Value *> +MicrosoftCXXABI::performBaseAdjustment(CodeGenFunction &CGF, Address Value, + QualType SrcRecordTy) { + Value = CGF.Builder.CreateBitCast(Value, CGF.Int8PtrTy); + const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl(); + const ASTContext &Context = getContext(); + + // If the class itself has a vfptr, great. This check implicitly + // covers non-virtual base subobjects: a class with its own virtual + // functions would be a candidate to be a primary base. + if (Context.getASTRecordLayout(SrcDecl).hasExtendableVFPtr()) + return std::make_pair(Value, llvm::ConstantInt::get(CGF.Int32Ty, 0)); + + // Okay, one of the vbases must have a vfptr, or else this isn't + // actually a polymorphic class. + const CXXRecordDecl *PolymorphicBase = nullptr; + for (auto &Base : SrcDecl->vbases()) { + const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl(); + if (Context.getASTRecordLayout(BaseDecl).hasExtendableVFPtr()) { + PolymorphicBase = BaseDecl; + break; + } + } + assert(PolymorphicBase && "polymorphic class has no apparent vfptr?"); + + llvm::Value *Offset = + GetVirtualBaseClassOffset(CGF, Value, SrcDecl, PolymorphicBase); + llvm::Value *Ptr = CGF.Builder.CreateInBoundsGEP(Value.getPointer(), Offset); + Offset = CGF.Builder.CreateTrunc(Offset, CGF.Int32Ty); + CharUnits VBaseAlign = + CGF.CGM.getVBaseAlignment(Value.getAlignment(), SrcDecl, PolymorphicBase); + return std::make_pair(Address(Ptr, VBaseAlign), Offset); +} + +bool MicrosoftCXXABI::shouldTypeidBeNullChecked(bool IsDeref, + QualType SrcRecordTy) { + const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl(); + return IsDeref && + !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr(); +} + +static llvm::CallSite emitRTtypeidCall(CodeGenFunction &CGF, + llvm::Value *Argument) { + llvm::Type *ArgTypes[] = {CGF.Int8PtrTy}; + llvm::FunctionType *FTy = + llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false); + llvm::Value *Args[] = {Argument}; + llvm::Constant *Fn = CGF.CGM.CreateRuntimeFunction(FTy, "__RTtypeid"); + return CGF.EmitRuntimeCallOrInvoke(Fn, Args); +} + +void MicrosoftCXXABI::EmitBadTypeidCall(CodeGenFunction &CGF) { + llvm::CallSite Call = + emitRTtypeidCall(CGF, llvm::Constant::getNullValue(CGM.VoidPtrTy)); + Call.setDoesNotReturn(); + CGF.Builder.CreateUnreachable(); +} + +llvm::Value *MicrosoftCXXABI::EmitTypeid(CodeGenFunction &CGF, + QualType SrcRecordTy, + Address ThisPtr, + llvm::Type *StdTypeInfoPtrTy) { + llvm::Value *Offset; + std::tie(ThisPtr, Offset) = performBaseAdjustment(CGF, ThisPtr, SrcRecordTy); + auto Typeid = emitRTtypeidCall(CGF, ThisPtr.getPointer()).getInstruction(); + return CGF.Builder.CreateBitCast(Typeid, StdTypeInfoPtrTy); +} + +bool MicrosoftCXXABI::shouldDynamicCastCallBeNullChecked(bool SrcIsPtr, + QualType SrcRecordTy) { + const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl(); + return SrcIsPtr && + !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr(); +} + +llvm::Value *MicrosoftCXXABI::EmitDynamicCastCall( + CodeGenFunction &CGF, Address This, QualType SrcRecordTy, + QualType DestTy, QualType DestRecordTy, llvm::BasicBlock *CastEnd) { + llvm::Type *DestLTy = CGF.ConvertType(DestTy); + + llvm::Value *SrcRTTI = + CGF.CGM.GetAddrOfRTTIDescriptor(SrcRecordTy.getUnqualifiedType()); + llvm::Value *DestRTTI = + CGF.CGM.GetAddrOfRTTIDescriptor(DestRecordTy.getUnqualifiedType()); + + llvm::Value *Offset; + std::tie(This, Offset) = performBaseAdjustment(CGF, This, SrcRecordTy); + llvm::Value *ThisPtr = This.getPointer(); + + // PVOID __RTDynamicCast( + // PVOID inptr, + // LONG VfDelta, + // PVOID SrcType, + // PVOID TargetType, + // BOOL isReference) + llvm::Type *ArgTypes[] = {CGF.Int8PtrTy, CGF.Int32Ty, CGF.Int8PtrTy, + CGF.Int8PtrTy, CGF.Int32Ty}; + llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction( + llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false), + "__RTDynamicCast"); + llvm::Value *Args[] = { + ThisPtr, Offset, SrcRTTI, DestRTTI, + llvm::ConstantInt::get(CGF.Int32Ty, DestTy->isReferenceType())}; + ThisPtr = CGF.EmitRuntimeCallOrInvoke(Function, Args).getInstruction(); + return CGF.Builder.CreateBitCast(ThisPtr, DestLTy); +} + +llvm::Value * +MicrosoftCXXABI::EmitDynamicCastToVoid(CodeGenFunction &CGF, Address Value, + QualType SrcRecordTy, + QualType DestTy) { + llvm::Value *Offset; + std::tie(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy); + + // PVOID __RTCastToVoid( + // PVOID inptr) + llvm::Type *ArgTypes[] = {CGF.Int8PtrTy}; + llvm::Constant *Function = CGF.CGM.CreateRuntimeFunction( + llvm::FunctionType::get(CGF.Int8PtrTy, ArgTypes, false), + "__RTCastToVoid"); + llvm::Value *Args[] = {Value.getPointer()}; + return CGF.EmitRuntimeCall(Function, Args); +} + +bool MicrosoftCXXABI::EmitBadCastCall(CodeGenFunction &CGF) { + return false; +} + +llvm::Value *MicrosoftCXXABI::GetVirtualBaseClassOffset( + CodeGenFunction &CGF, Address This, const CXXRecordDecl *ClassDecl, + const CXXRecordDecl *BaseClassDecl) { + const ASTContext &Context = getContext(); + int64_t VBPtrChars = + Context.getASTRecordLayout(ClassDecl).getVBPtrOffset().getQuantity(); + llvm::Value *VBPtrOffset = llvm::ConstantInt::get(CGM.PtrDiffTy, VBPtrChars); + CharUnits IntSize = Context.getTypeSizeInChars(Context.IntTy); + CharUnits VBTableChars = + IntSize * + CGM.getMicrosoftVTableContext().getVBTableIndex(ClassDecl, BaseClassDecl); + llvm::Value *VBTableOffset = + llvm::ConstantInt::get(CGM.IntTy, VBTableChars.getQuantity()); + + llvm::Value *VBPtrToNewBase = + GetVBaseOffsetFromVBPtr(CGF, This, VBPtrOffset, VBTableOffset); + VBPtrToNewBase = + CGF.Builder.CreateSExtOrBitCast(VBPtrToNewBase, CGM.PtrDiffTy); + return CGF.Builder.CreateNSWAdd(VBPtrOffset, VBPtrToNewBase); +} + +bool MicrosoftCXXABI::HasThisReturn(GlobalDecl GD) const { + return isa<CXXConstructorDecl>(GD.getDecl()); +} + +static bool isDeletingDtor(GlobalDecl GD) { + return isa<CXXDestructorDecl>(GD.getDecl()) && + GD.getDtorType() == Dtor_Deleting; +} + +bool MicrosoftCXXABI::hasMostDerivedReturn(GlobalDecl GD) const { + return isDeletingDtor(GD); +} + +bool MicrosoftCXXABI::classifyReturnType(CGFunctionInfo &FI) const { + const CXXRecordDecl *RD = FI.getReturnType()->getAsCXXRecordDecl(); + if (!RD) + return false; + + CharUnits Align = CGM.getContext().getTypeAlignInChars(FI.getReturnType()); + if (FI.isInstanceMethod()) { + // If it's an instance method, aggregates are always returned indirectly via + // the second parameter. + FI.getReturnInfo() = ABIArgInfo::getIndirect(Align, /*ByVal=*/false); + FI.getReturnInfo().setSRetAfterThis(FI.isInstanceMethod()); + return true; + } else if (!RD->isPOD()) { + // If it's a free function, non-POD types are returned indirectly. + FI.getReturnInfo() = ABIArgInfo::getIndirect(Align, /*ByVal=*/false); + return true; + } + + // Otherwise, use the C ABI rules. + return false; +} + +llvm::BasicBlock * +MicrosoftCXXABI::EmitCtorCompleteObjectHandler(CodeGenFunction &CGF, + const CXXRecordDecl *RD) { + llvm::Value *IsMostDerivedClass = getStructorImplicitParamValue(CGF); + assert(IsMostDerivedClass && + "ctor for a class with virtual bases must have an implicit parameter"); + llvm::Value *IsCompleteObject = + CGF.Builder.CreateIsNotNull(IsMostDerivedClass, "is_complete_object"); + + llvm::BasicBlock *CallVbaseCtorsBB = CGF.createBasicBlock("ctor.init_vbases"); + llvm::BasicBlock *SkipVbaseCtorsBB = CGF.createBasicBlock("ctor.skip_vbases"); + CGF.Builder.CreateCondBr(IsCompleteObject, + CallVbaseCtorsBB, SkipVbaseCtorsBB); + + CGF.EmitBlock(CallVbaseCtorsBB); + + // Fill in the vbtable pointers here. + EmitVBPtrStores(CGF, RD); + + // CGF will put the base ctor calls in this basic block for us later. + + return SkipVbaseCtorsBB; +} + +void MicrosoftCXXABI::initializeHiddenVirtualInheritanceMembers( + CodeGenFunction &CGF, const CXXRecordDecl *RD) { + // In most cases, an override for a vbase virtual method can adjust + // the "this" parameter by applying a constant offset. + // However, this is not enough while a constructor or a destructor of some + // class X is being executed if all the following conditions are met: + // - X has virtual bases, (1) + // - X overrides a virtual method M of a vbase Y, (2) + // - X itself is a vbase of the most derived class. + // + // If (1) and (2) are true, the vtorDisp for vbase Y is a hidden member of X + // which holds the extra amount of "this" adjustment we must do when we use + // the X vftables (i.e. during X ctor or dtor). + // Outside the ctors and dtors, the values of vtorDisps are zero. + + const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD); + typedef ASTRecordLayout::VBaseOffsetsMapTy VBOffsets; + const VBOffsets &VBaseMap = Layout.getVBaseOffsetsMap(); + CGBuilderTy &Builder = CGF.Builder; + + unsigned AS = getThisAddress(CGF).getAddressSpace(); + llvm::Value *Int8This = nullptr; // Initialize lazily. + + for (VBOffsets::const_iterator I = VBaseMap.begin(), E = VBaseMap.end(); + I != E; ++I) { + if (!I->second.hasVtorDisp()) + continue; + + llvm::Value *VBaseOffset = + GetVirtualBaseClassOffset(CGF, getThisAddress(CGF), RD, I->first); + // FIXME: it doesn't look right that we SExt in GetVirtualBaseClassOffset() + // just to Trunc back immediately. + VBaseOffset = Builder.CreateTruncOrBitCast(VBaseOffset, CGF.Int32Ty); + uint64_t ConstantVBaseOffset = + Layout.getVBaseClassOffset(I->first).getQuantity(); + + // vtorDisp_for_vbase = vbptr[vbase_idx] - offsetof(RD, vbase). + llvm::Value *VtorDispValue = Builder.CreateSub( + VBaseOffset, llvm::ConstantInt::get(CGM.Int32Ty, ConstantVBaseOffset), + "vtordisp.value"); + + if (!Int8This) + Int8This = Builder.CreateBitCast(getThisValue(CGF), + CGF.Int8Ty->getPointerTo(AS)); + llvm::Value *VtorDispPtr = Builder.CreateInBoundsGEP(Int8This, VBaseOffset); + // vtorDisp is always the 32-bits before the vbase in the class layout. + VtorDispPtr = Builder.CreateConstGEP1_32(VtorDispPtr, -4); + VtorDispPtr = Builder.CreateBitCast( + VtorDispPtr, CGF.Int32Ty->getPointerTo(AS), "vtordisp.ptr"); + + Builder.CreateAlignedStore(VtorDispValue, VtorDispPtr, + CharUnits::fromQuantity(4)); + } +} + +static bool hasDefaultCXXMethodCC(ASTContext &Context, + const CXXMethodDecl *MD) { + CallingConv ExpectedCallingConv = Context.getDefaultCallingConvention( + /*IsVariadic=*/false, /*IsCXXMethod=*/true); + CallingConv ActualCallingConv = + MD->getType()->getAs<FunctionProtoType>()->getCallConv(); + return ExpectedCallingConv == ActualCallingConv; +} + +void MicrosoftCXXABI::EmitCXXConstructors(const CXXConstructorDecl *D) { + // There's only one constructor type in this ABI. + CGM.EmitGlobal(GlobalDecl(D, Ctor_Complete)); + + // Exported default constructors either have a simple call-site where they use + // the typical calling convention and have a single 'this' pointer for an + // argument -or- they get a wrapper function which appropriately thunks to the + // real default constructor. This thunk is the default constructor closure. + if (D->hasAttr<DLLExportAttr>() && D->isDefaultConstructor()) + if (!hasDefaultCXXMethodCC(getContext(), D) || D->getNumParams() != 0) { + llvm::Function *Fn = getAddrOfCXXCtorClosure(D, Ctor_DefaultClosure); + Fn->setLinkage(llvm::GlobalValue::WeakODRLinkage); + Fn->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass); + } +} + +void MicrosoftCXXABI::EmitVBPtrStores(CodeGenFunction &CGF, + const CXXRecordDecl *RD) { + Address This = getThisAddress(CGF); + This = CGF.Builder.CreateElementBitCast(This, CGM.Int8Ty, "this.int8"); + const ASTContext &Context = getContext(); + const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD); + + const VBTableGlobals &VBGlobals = enumerateVBTables(RD); + for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) { + const VPtrInfo *VBT = (*VBGlobals.VBTables)[I]; + llvm::GlobalVariable *GV = VBGlobals.Globals[I]; + const ASTRecordLayout &SubobjectLayout = + Context.getASTRecordLayout(VBT->BaseWithVPtr); + CharUnits Offs = VBT->NonVirtualOffset; + Offs += SubobjectLayout.getVBPtrOffset(); + if (VBT->getVBaseWithVPtr()) + Offs += Layout.getVBaseClassOffset(VBT->getVBaseWithVPtr()); + Address VBPtr = CGF.Builder.CreateConstInBoundsByteGEP(This, Offs); + llvm::Value *GVPtr = + CGF.Builder.CreateConstInBoundsGEP2_32(GV->getValueType(), GV, 0, 0); + VBPtr = CGF.Builder.CreateElementBitCast(VBPtr, GVPtr->getType(), + "vbptr." + VBT->ReusingBase->getName()); + CGF.Builder.CreateStore(GVPtr, VBPtr); + } +} + +void +MicrosoftCXXABI::buildStructorSignature(const CXXMethodDecl *MD, StructorType T, + SmallVectorImpl<CanQualType> &ArgTys) { + // TODO: 'for base' flag + if (T == StructorType::Deleting) { + // The scalar deleting destructor takes an implicit int parameter. + ArgTys.push_back(getContext().IntTy); + } + auto *CD = dyn_cast<CXXConstructorDecl>(MD); + if (!CD) + return; + + // All parameters are already in place except is_most_derived, which goes + // after 'this' if it's variadic and last if it's not. + + const CXXRecordDecl *Class = CD->getParent(); + const FunctionProtoType *FPT = CD->getType()->castAs<FunctionProtoType>(); + if (Class->getNumVBases()) { + if (FPT->isVariadic()) + ArgTys.insert(ArgTys.begin() + 1, getContext().IntTy); + else + ArgTys.push_back(getContext().IntTy); + } +} + +void MicrosoftCXXABI::EmitCXXDestructors(const CXXDestructorDecl *D) { + // The TU defining a dtor is only guaranteed to emit a base destructor. All + // other destructor variants are delegating thunks. + CGM.EmitGlobal(GlobalDecl(D, Dtor_Base)); +} + +CharUnits +MicrosoftCXXABI::getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) { + GD = GD.getCanonicalDecl(); + const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl()); + + GlobalDecl LookupGD = GD; + if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) { + // Complete destructors take a pointer to the complete object as a + // parameter, thus don't need this adjustment. + if (GD.getDtorType() == Dtor_Complete) + return CharUnits(); + + // There's no Dtor_Base in vftable but it shares the this adjustment with + // the deleting one, so look it up instead. + LookupGD = GlobalDecl(DD, Dtor_Deleting); + } + + MicrosoftVTableContext::MethodVFTableLocation ML = + CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD); + CharUnits Adjustment = ML.VFPtrOffset; + + // Normal virtual instance methods need to adjust from the vfptr that first + // defined the virtual method to the virtual base subobject, but destructors + // do not. The vector deleting destructor thunk applies this adjustment for + // us if necessary. + if (isa<CXXDestructorDecl>(MD)) + Adjustment = CharUnits::Zero(); + + if (ML.VBase) { + const ASTRecordLayout &DerivedLayout = + getContext().getASTRecordLayout(MD->getParent()); + Adjustment += DerivedLayout.getVBaseClassOffset(ML.VBase); + } + + return Adjustment; +} + +Address MicrosoftCXXABI::adjustThisArgumentForVirtualFunctionCall( + CodeGenFunction &CGF, GlobalDecl GD, Address This, + bool VirtualCall) { + if (!VirtualCall) { + // If the call of a virtual function is not virtual, we just have to + // compensate for the adjustment the virtual function does in its prologue. + CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD); + if (Adjustment.isZero()) + return This; + + This = CGF.Builder.CreateElementBitCast(This, CGF.Int8Ty); + assert(Adjustment.isPositive()); + return CGF.Builder.CreateConstByteGEP(This, Adjustment); + } + + GD = GD.getCanonicalDecl(); + const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl()); + + GlobalDecl LookupGD = GD; + if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) { + // Complete dtors take a pointer to the complete object, + // thus don't need adjustment. + if (GD.getDtorType() == Dtor_Complete) + return This; + + // There's only Dtor_Deleting in vftable but it shares the this adjustment + // with the base one, so look up the deleting one instead. + LookupGD = GlobalDecl(DD, Dtor_Deleting); + } + MicrosoftVTableContext::MethodVFTableLocation ML = + CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD); + + CharUnits StaticOffset = ML.VFPtrOffset; + + // Base destructors expect 'this' to point to the beginning of the base + // subobject, not the first vfptr that happens to contain the virtual dtor. + // However, we still need to apply the virtual base adjustment. + if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base) + StaticOffset = CharUnits::Zero(); + + Address Result = This; + if (ML.VBase) { + Result = CGF.Builder.CreateElementBitCast(Result, CGF.Int8Ty); + + const CXXRecordDecl *Derived = MD->getParent(); + const CXXRecordDecl *VBase = ML.VBase; + llvm::Value *VBaseOffset = + GetVirtualBaseClassOffset(CGF, Result, Derived, VBase); + llvm::Value *VBasePtr = + CGF.Builder.CreateInBoundsGEP(Result.getPointer(), VBaseOffset); + CharUnits VBaseAlign = + CGF.CGM.getVBaseAlignment(Result.getAlignment(), Derived, VBase); + Result = Address(VBasePtr, VBaseAlign); + } + if (!StaticOffset.isZero()) { + assert(StaticOffset.isPositive()); + Result = CGF.Builder.CreateElementBitCast(Result, CGF.Int8Ty); + if (ML.VBase) { + // Non-virtual adjustment might result in a pointer outside the allocated + // object, e.g. if the final overrider class is laid out after the virtual + // base that declares a method in the most derived class. + // FIXME: Update the code that emits this adjustment in thunks prologues. + Result = CGF.Builder.CreateConstByteGEP(Result, StaticOffset); + } else { + Result = CGF.Builder.CreateConstInBoundsByteGEP(Result, StaticOffset); + } + } + return Result; +} + +void MicrosoftCXXABI::addImplicitStructorParams(CodeGenFunction &CGF, + QualType &ResTy, + FunctionArgList &Params) { + ASTContext &Context = getContext(); + const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl()); + assert(isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD)); + if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) { + ImplicitParamDecl *IsMostDerived + = ImplicitParamDecl::Create(Context, nullptr, + CGF.CurGD.getDecl()->getLocation(), + &Context.Idents.get("is_most_derived"), + Context.IntTy); + // The 'most_derived' parameter goes second if the ctor is variadic and last + // if it's not. Dtors can't be variadic. + const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>(); + if (FPT->isVariadic()) + Params.insert(Params.begin() + 1, IsMostDerived); + else + Params.push_back(IsMostDerived); + getStructorImplicitParamDecl(CGF) = IsMostDerived; + } else if (isDeletingDtor(CGF.CurGD)) { + ImplicitParamDecl *ShouldDelete + = ImplicitParamDecl::Create(Context, nullptr, + CGF.CurGD.getDecl()->getLocation(), + &Context.Idents.get("should_call_delete"), + Context.IntTy); + Params.push_back(ShouldDelete); + getStructorImplicitParamDecl(CGF) = ShouldDelete; + } +} + +llvm::Value *MicrosoftCXXABI::adjustThisParameterInVirtualFunctionPrologue( + CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) { + // In this ABI, every virtual function takes a pointer to one of the + // subobjects that first defines it as the 'this' parameter, rather than a + // pointer to the final overrider subobject. Thus, we need to adjust it back + // to the final overrider subobject before use. + // See comments in the MicrosoftVFTableContext implementation for the details. + CharUnits Adjustment = getVirtualFunctionPrologueThisAdjustment(GD); + if (Adjustment.isZero()) + return This; + + unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace(); + llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS), + *thisTy = This->getType(); + + This = CGF.Builder.CreateBitCast(This, charPtrTy); + assert(Adjustment.isPositive()); + This = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, This, + -Adjustment.getQuantity()); + return CGF.Builder.CreateBitCast(This, thisTy); +} + +void MicrosoftCXXABI::EmitInstanceFunctionProlog(CodeGenFunction &CGF) { + EmitThisParam(CGF); + + /// If this is a function that the ABI specifies returns 'this', initialize + /// the return slot to 'this' at the start of the function. + /// + /// Unlike the setting of return types, this is done within the ABI + /// implementation instead of by clients of CGCXXABI because: + /// 1) getThisValue is currently protected + /// 2) in theory, an ABI could implement 'this' returns some other way; + /// HasThisReturn only specifies a contract, not the implementation + if (HasThisReturn(CGF.CurGD)) + CGF.Builder.CreateStore(getThisValue(CGF), CGF.ReturnValue); + else if (hasMostDerivedReturn(CGF.CurGD)) + CGF.Builder.CreateStore(CGF.EmitCastToVoidPtr(getThisValue(CGF)), + CGF.ReturnValue); + + const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl()); + if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) { + assert(getStructorImplicitParamDecl(CGF) && + "no implicit parameter for a constructor with virtual bases?"); + getStructorImplicitParamValue(CGF) + = CGF.Builder.CreateLoad( + CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)), + "is_most_derived"); + } + + if (isDeletingDtor(CGF.CurGD)) { + assert(getStructorImplicitParamDecl(CGF) && + "no implicit parameter for a deleting destructor?"); + getStructorImplicitParamValue(CGF) + = CGF.Builder.CreateLoad( + CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)), + "should_call_delete"); + } +} + +unsigned MicrosoftCXXABI::addImplicitConstructorArgs( + CodeGenFunction &CGF, const CXXConstructorDecl *D, CXXCtorType Type, + bool ForVirtualBase, bool Delegating, CallArgList &Args) { + assert(Type == Ctor_Complete || Type == Ctor_Base); + + // Check if we need a 'most_derived' parameter. + if (!D->getParent()->getNumVBases()) + return 0; + + // Add the 'most_derived' argument second if we are variadic or last if not. + const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>(); + llvm::Value *MostDerivedArg = + llvm::ConstantInt::get(CGM.Int32Ty, Type == Ctor_Complete); + RValue RV = RValue::get(MostDerivedArg); + if (MostDerivedArg) { + if (FPT->isVariadic()) + Args.insert(Args.begin() + 1, + CallArg(RV, getContext().IntTy, /*needscopy=*/false)); + else + Args.add(RV, getContext().IntTy); + } + + return 1; // Added one arg. +} + +void MicrosoftCXXABI::EmitDestructorCall(CodeGenFunction &CGF, + const CXXDestructorDecl *DD, + CXXDtorType Type, bool ForVirtualBase, + bool Delegating, Address This) { + llvm::Value *Callee = CGM.getAddrOfCXXStructor(DD, getFromDtorType(Type)); + + if (DD->isVirtual()) { + assert(Type != CXXDtorType::Dtor_Deleting && + "The deleting destructor should only be called via a virtual call"); + This = adjustThisArgumentForVirtualFunctionCall(CGF, GlobalDecl(DD, Type), + This, false); + } + + CGF.EmitCXXStructorCall(DD, Callee, ReturnValueSlot(), This.getPointer(), + /*ImplicitParam=*/nullptr, + /*ImplicitParamTy=*/QualType(), nullptr, + getFromDtorType(Type)); +} + +void MicrosoftCXXABI::emitVTableBitSetEntries(VPtrInfo *Info, + const CXXRecordDecl *RD, + llvm::GlobalVariable *VTable) { + if (!getContext().getLangOpts().Sanitize.has(SanitizerKind::CFIVCall) && + !getContext().getLangOpts().Sanitize.has(SanitizerKind::CFINVCall) && + !getContext().getLangOpts().Sanitize.has(SanitizerKind::CFIDerivedCast) && + !getContext().getLangOpts().Sanitize.has(SanitizerKind::CFIUnrelatedCast)) + return; + + llvm::NamedMDNode *BitsetsMD = + CGM.getModule().getOrInsertNamedMetadata("llvm.bitsets"); + + // The location of the first virtual function pointer in the virtual table, + // aka the "address point" on Itanium. This is at offset 0 if RTTI is + // disabled, or sizeof(void*) if RTTI is enabled. + CharUnits AddressPoint = + getContext().getLangOpts().RTTIData + ? getContext().toCharUnitsFromBits( + getContext().getTargetInfo().getPointerWidth(0)) + : CharUnits::Zero(); + + if (Info->PathToBaseWithVPtr.empty()) { + if (!CGM.IsCFIBlacklistedRecord(RD)) + CGM.CreateVTableBitSetEntry(BitsetsMD, VTable, AddressPoint, RD); + return; + } + + // Add a bitset entry for the least derived base belonging to this vftable. + if (!CGM.IsCFIBlacklistedRecord(Info->PathToBaseWithVPtr.back())) + CGM.CreateVTableBitSetEntry(BitsetsMD, VTable, AddressPoint, + Info->PathToBaseWithVPtr.back()); + + // Add a bitset entry for each derived class that is laid out at the same + // offset as the least derived base. + for (unsigned I = Info->PathToBaseWithVPtr.size() - 1; I != 0; --I) { + const CXXRecordDecl *DerivedRD = Info->PathToBaseWithVPtr[I - 1]; + const CXXRecordDecl *BaseRD = Info->PathToBaseWithVPtr[I]; + + const ASTRecordLayout &Layout = + getContext().getASTRecordLayout(DerivedRD); + CharUnits Offset; + auto VBI = Layout.getVBaseOffsetsMap().find(BaseRD); + if (VBI == Layout.getVBaseOffsetsMap().end()) + Offset = Layout.getBaseClassOffset(BaseRD); + else + Offset = VBI->second.VBaseOffset; + if (!Offset.isZero()) + return; + if (!CGM.IsCFIBlacklistedRecord(DerivedRD)) + CGM.CreateVTableBitSetEntry(BitsetsMD, VTable, AddressPoint, DerivedRD); + } + + // Finally do the same for the most derived class. + if (Info->FullOffsetInMDC.isZero() && !CGM.IsCFIBlacklistedRecord(RD)) + CGM.CreateVTableBitSetEntry(BitsetsMD, VTable, AddressPoint, RD); +} + +void MicrosoftCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT, + const CXXRecordDecl *RD) { + MicrosoftVTableContext &VFTContext = CGM.getMicrosoftVTableContext(); + const VPtrInfoVector &VFPtrs = VFTContext.getVFPtrOffsets(RD); + + for (VPtrInfo *Info : VFPtrs) { + llvm::GlobalVariable *VTable = getAddrOfVTable(RD, Info->FullOffsetInMDC); + if (VTable->hasInitializer()) + continue; + + llvm::Constant *RTTI = getContext().getLangOpts().RTTIData + ? getMSCompleteObjectLocator(RD, Info) + : nullptr; + + const VTableLayout &VTLayout = + VFTContext.getVFTableLayout(RD, Info->FullOffsetInMDC); + llvm::Constant *Init = CGVT.CreateVTableInitializer( + RD, VTLayout.vtable_component_begin(), + VTLayout.getNumVTableComponents(), VTLayout.vtable_thunk_begin(), + VTLayout.getNumVTableThunks(), RTTI); + + VTable->setInitializer(Init); + + emitVTableBitSetEntries(Info, RD, VTable); + } +} + +bool MicrosoftCXXABI::isVirtualOffsetNeededForVTableField( + CodeGenFunction &CGF, CodeGenFunction::VPtr Vptr) { + return Vptr.NearestVBase != nullptr; +} + +llvm::Value *MicrosoftCXXABI::getVTableAddressPointInStructor( + CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, BaseSubobject Base, + const CXXRecordDecl *NearestVBase) { + llvm::Constant *VTableAddressPoint = getVTableAddressPoint(Base, VTableClass); + if (!VTableAddressPoint) { + assert(Base.getBase()->getNumVBases() && + !getContext().getASTRecordLayout(Base.getBase()).hasOwnVFPtr()); + } + return VTableAddressPoint; +} + +static void mangleVFTableName(MicrosoftMangleContext &MangleContext, + const CXXRecordDecl *RD, const VPtrInfo *VFPtr, + SmallString<256> &Name) { + llvm::raw_svector_ostream Out(Name); + MangleContext.mangleCXXVFTable(RD, VFPtr->MangledPath, Out); +} + +llvm::Constant * +MicrosoftCXXABI::getVTableAddressPoint(BaseSubobject Base, + const CXXRecordDecl *VTableClass) { + (void)getAddrOfVTable(VTableClass, Base.getBaseOffset()); + VFTableIdTy ID(VTableClass, Base.getBaseOffset()); + return VFTablesMap[ID]; +} + +llvm::Constant *MicrosoftCXXABI::getVTableAddressPointForConstExpr( + BaseSubobject Base, const CXXRecordDecl *VTableClass) { + llvm::Constant *VFTable = getVTableAddressPoint(Base, VTableClass); + assert(VFTable && "Couldn't find a vftable for the given base?"); + return VFTable; +} + +llvm::GlobalVariable *MicrosoftCXXABI::getAddrOfVTable(const CXXRecordDecl *RD, + CharUnits VPtrOffset) { + // getAddrOfVTable may return 0 if asked to get an address of a vtable which + // shouldn't be used in the given record type. We want to cache this result in + // VFTablesMap, thus a simple zero check is not sufficient. + + VFTableIdTy ID(RD, VPtrOffset); + VTablesMapTy::iterator I; + bool Inserted; + std::tie(I, Inserted) = VTablesMap.insert(std::make_pair(ID, nullptr)); + if (!Inserted) + return I->second; + + llvm::GlobalVariable *&VTable = I->second; + + MicrosoftVTableContext &VTContext = CGM.getMicrosoftVTableContext(); + const VPtrInfoVector &VFPtrs = VTContext.getVFPtrOffsets(RD); + + if (DeferredVFTables.insert(RD).second) { + // We haven't processed this record type before. + // Queue up this v-table for possible deferred emission. + CGM.addDeferredVTable(RD); + +#ifndef NDEBUG + // Create all the vftables at once in order to make sure each vftable has + // a unique mangled name. + llvm::StringSet<> ObservedMangledNames; + for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) { + SmallString<256> Name; + mangleVFTableName(getMangleContext(), RD, VFPtrs[J], Name); + if (!ObservedMangledNames.insert(Name.str()).second) + llvm_unreachable("Already saw this mangling before?"); + } +#endif + } + + VPtrInfo *const *VFPtrI = + std::find_if(VFPtrs.begin(), VFPtrs.end(), [&](VPtrInfo *VPI) { + return VPI->FullOffsetInMDC == VPtrOffset; + }); + if (VFPtrI == VFPtrs.end()) { + VFTablesMap[ID] = nullptr; + return nullptr; + } + VPtrInfo *VFPtr = *VFPtrI; + + SmallString<256> VFTableName; + mangleVFTableName(getMangleContext(), RD, VFPtr, VFTableName); + + llvm::GlobalValue::LinkageTypes VFTableLinkage = CGM.getVTableLinkage(RD); + bool VFTableComesFromAnotherTU = + llvm::GlobalValue::isAvailableExternallyLinkage(VFTableLinkage) || + llvm::GlobalValue::isExternalLinkage(VFTableLinkage); + bool VTableAliasIsRequred = + !VFTableComesFromAnotherTU && getContext().getLangOpts().RTTIData; + + if (llvm::GlobalValue *VFTable = + CGM.getModule().getNamedGlobal(VFTableName)) { + VFTablesMap[ID] = VFTable; + VTable = VTableAliasIsRequred + ? cast<llvm::GlobalVariable>( + cast<llvm::GlobalAlias>(VFTable)->getBaseObject()) + : cast<llvm::GlobalVariable>(VFTable); + return VTable; + } + + uint64_t NumVTableSlots = + VTContext.getVFTableLayout(RD, VFPtr->FullOffsetInMDC) + .getNumVTableComponents(); + llvm::GlobalValue::LinkageTypes VTableLinkage = + VTableAliasIsRequred ? llvm::GlobalValue::PrivateLinkage : VFTableLinkage; + + StringRef VTableName = VTableAliasIsRequred ? StringRef() : VFTableName.str(); + + llvm::ArrayType *VTableType = + llvm::ArrayType::get(CGM.Int8PtrTy, NumVTableSlots); + + // Create a backing variable for the contents of VTable. The VTable may + // or may not include space for a pointer to RTTI data. + llvm::GlobalValue *VFTable; + VTable = new llvm::GlobalVariable(CGM.getModule(), VTableType, + /*isConstant=*/true, VTableLinkage, + /*Initializer=*/nullptr, VTableName); + VTable->setUnnamedAddr(true); + + llvm::Comdat *C = nullptr; + if (!VFTableComesFromAnotherTU && + (llvm::GlobalValue::isWeakForLinker(VFTableLinkage) || + (llvm::GlobalValue::isLocalLinkage(VFTableLinkage) && + VTableAliasIsRequred))) + C = CGM.getModule().getOrInsertComdat(VFTableName.str()); + + // Only insert a pointer into the VFTable for RTTI data if we are not + // importing it. We never reference the RTTI data directly so there is no + // need to make room for it. + if (VTableAliasIsRequred) { + llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0), + llvm::ConstantInt::get(CGM.IntTy, 1)}; + // Create a GEP which points just after the first entry in the VFTable, + // this should be the location of the first virtual method. + llvm::Constant *VTableGEP = llvm::ConstantExpr::getInBoundsGetElementPtr( + VTable->getValueType(), VTable, GEPIndices); + if (llvm::GlobalValue::isWeakForLinker(VFTableLinkage)) { + VFTableLinkage = llvm::GlobalValue::ExternalLinkage; + if (C) + C->setSelectionKind(llvm::Comdat::Largest); + } + VFTable = llvm::GlobalAlias::create(CGM.Int8PtrTy, + /*AddressSpace=*/0, VFTableLinkage, + VFTableName.str(), VTableGEP, + &CGM.getModule()); + VFTable->setUnnamedAddr(true); + } else { + // We don't need a GlobalAlias to be a symbol for the VTable if we won't + // be referencing any RTTI data. + // The GlobalVariable will end up being an appropriate definition of the + // VFTable. + VFTable = VTable; + } + if (C) + VTable->setComdat(C); + + if (RD->hasAttr<DLLImportAttr>()) + VFTable->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass); + else if (RD->hasAttr<DLLExportAttr>()) + VFTable->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass); + + VFTablesMap[ID] = VFTable; + return VTable; +} + +// Compute the identity of the most derived class whose virtual table is located +// at the given offset into RD. +static const CXXRecordDecl *getClassAtVTableLocation(ASTContext &Ctx, + const CXXRecordDecl *RD, + CharUnits Offset) { + if (Offset.isZero()) + return RD; + + const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(RD); + const CXXRecordDecl *MaxBase = nullptr; + CharUnits MaxBaseOffset; + for (auto &&B : RD->bases()) { + const CXXRecordDecl *Base = B.getType()->getAsCXXRecordDecl(); + CharUnits BaseOffset = Layout.getBaseClassOffset(Base); + if (BaseOffset <= Offset && BaseOffset >= MaxBaseOffset) { + MaxBase = Base; + MaxBaseOffset = BaseOffset; + } + } + for (auto &&B : RD->vbases()) { + const CXXRecordDecl *Base = B.getType()->getAsCXXRecordDecl(); + CharUnits BaseOffset = Layout.getVBaseClassOffset(Base); + if (BaseOffset <= Offset && BaseOffset >= MaxBaseOffset) { + MaxBase = Base; + MaxBaseOffset = BaseOffset; + } + } + assert(MaxBase); + return getClassAtVTableLocation(Ctx, MaxBase, Offset - MaxBaseOffset); +} + +// Compute the identity of the most derived class whose virtual table is located +// at the MethodVFTableLocation ML. +static const CXXRecordDecl * +getClassAtVTableLocation(ASTContext &Ctx, GlobalDecl GD, + MicrosoftVTableContext::MethodVFTableLocation &ML) { + const CXXRecordDecl *RD = ML.VBase; + if (!RD) + RD = cast<CXXMethodDecl>(GD.getDecl())->getParent(); + + return getClassAtVTableLocation(Ctx, RD, ML.VFPtrOffset); +} + +llvm::Value *MicrosoftCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF, + GlobalDecl GD, + Address This, + llvm::Type *Ty, + SourceLocation Loc) { + GD = GD.getCanonicalDecl(); + CGBuilderTy &Builder = CGF.Builder; + + Ty = Ty->getPointerTo()->getPointerTo(); + Address VPtr = + adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true); + + auto *MethodDecl = cast<CXXMethodDecl>(GD.getDecl()); + llvm::Value *VTable = CGF.GetVTablePtr(VPtr, Ty, MethodDecl->getParent()); + + MicrosoftVTableContext::MethodVFTableLocation ML = + CGM.getMicrosoftVTableContext().getMethodVFTableLocation(GD); + if (CGF.SanOpts.has(SanitizerKind::CFIVCall)) + CGF.EmitVTablePtrCheck(getClassAtVTableLocation(getContext(), GD, ML), + VTable, CodeGenFunction::CFITCK_VCall, Loc); + + llvm::Value *VFuncPtr = + Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn"); + return Builder.CreateAlignedLoad(VFuncPtr, CGF.getPointerAlign()); +} + +llvm::Value *MicrosoftCXXABI::EmitVirtualDestructorCall( + CodeGenFunction &CGF, const CXXDestructorDecl *Dtor, CXXDtorType DtorType, + Address This, const CXXMemberCallExpr *CE) { + assert(CE == nullptr || CE->arg_begin() == CE->arg_end()); + assert(DtorType == Dtor_Deleting || DtorType == Dtor_Complete); + + // We have only one destructor in the vftable but can get both behaviors + // by passing an implicit int parameter. + GlobalDecl GD(Dtor, Dtor_Deleting); + const CGFunctionInfo *FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration( + Dtor, StructorType::Deleting); + llvm::Type *Ty = CGF.CGM.getTypes().GetFunctionType(*FInfo); + llvm::Value *Callee = getVirtualFunctionPointer( + CGF, GD, This, Ty, CE ? CE->getLocStart() : SourceLocation()); + + ASTContext &Context = getContext(); + llvm::Value *ImplicitParam = llvm::ConstantInt::get( + llvm::IntegerType::getInt32Ty(CGF.getLLVMContext()), + DtorType == Dtor_Deleting); + + This = adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true); + RValue RV = CGF.EmitCXXStructorCall(Dtor, Callee, ReturnValueSlot(), + This.getPointer(), + ImplicitParam, Context.IntTy, CE, + StructorType::Deleting); + return RV.getScalarVal(); +} + +const VBTableGlobals & +MicrosoftCXXABI::enumerateVBTables(const CXXRecordDecl *RD) { + // At this layer, we can key the cache off of a single class, which is much + // easier than caching each vbtable individually. + llvm::DenseMap<const CXXRecordDecl*, VBTableGlobals>::iterator Entry; + bool Added; + std::tie(Entry, Added) = + VBTablesMap.insert(std::make_pair(RD, VBTableGlobals())); + VBTableGlobals &VBGlobals = Entry->second; + if (!Added) + return VBGlobals; + + MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext(); + VBGlobals.VBTables = &Context.enumerateVBTables(RD); + + // Cache the globals for all vbtables so we don't have to recompute the + // mangled names. + llvm::GlobalVariable::LinkageTypes Linkage = CGM.getVTableLinkage(RD); + for (VPtrInfoVector::const_iterator I = VBGlobals.VBTables->begin(), + E = VBGlobals.VBTables->end(); + I != E; ++I) { + VBGlobals.Globals.push_back(getAddrOfVBTable(**I, RD, Linkage)); + } + + return VBGlobals; +} + +llvm::Function *MicrosoftCXXABI::EmitVirtualMemPtrThunk( + const CXXMethodDecl *MD, + const MicrosoftVTableContext::MethodVFTableLocation &ML) { + assert(!isa<CXXConstructorDecl>(MD) && !isa<CXXDestructorDecl>(MD) && + "can't form pointers to ctors or virtual dtors"); + + // Calculate the mangled name. + SmallString<256> ThunkName; + llvm::raw_svector_ostream Out(ThunkName); + getMangleContext().mangleVirtualMemPtrThunk(MD, Out); + + // If the thunk has been generated previously, just return it. + if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName)) + return cast<llvm::Function>(GV); + + // Create the llvm::Function. + const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSMemberPointerThunk(MD); + llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo); + llvm::Function *ThunkFn = + llvm::Function::Create(ThunkTy, llvm::Function::ExternalLinkage, + ThunkName.str(), &CGM.getModule()); + assert(ThunkFn->getName() == ThunkName && "name was uniqued!"); + + ThunkFn->setLinkage(MD->isExternallyVisible() + ? llvm::GlobalValue::LinkOnceODRLinkage + : llvm::GlobalValue::InternalLinkage); + if (MD->isExternallyVisible()) + ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName())); + + CGM.SetLLVMFunctionAttributes(MD, FnInfo, ThunkFn); + CGM.SetLLVMFunctionAttributesForDefinition(MD, ThunkFn); + + // Add the "thunk" attribute so that LLVM knows that the return type is + // meaningless. These thunks can be used to call functions with differing + // return types, and the caller is required to cast the prototype + // appropriately to extract the correct value. + ThunkFn->addFnAttr("thunk"); + + // These thunks can be compared, so they are not unnamed. + ThunkFn->setUnnamedAddr(false); + + // Start codegen. + CodeGenFunction CGF(CGM); + CGF.CurGD = GlobalDecl(MD); + CGF.CurFuncIsThunk = true; + + // Build FunctionArgs, but only include the implicit 'this' parameter + // declaration. + FunctionArgList FunctionArgs; + buildThisParam(CGF, FunctionArgs); + + // Start defining the function. + CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo, + FunctionArgs, MD->getLocation(), SourceLocation()); + EmitThisParam(CGF); + + // Load the vfptr and then callee from the vftable. The callee should have + // adjusted 'this' so that the vfptr is at offset zero. + llvm::Value *VTable = CGF.GetVTablePtr( + getThisAddress(CGF), ThunkTy->getPointerTo()->getPointerTo(), MD->getParent()); + + llvm::Value *VFuncPtr = + CGF.Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn"); + llvm::Value *Callee = + CGF.Builder.CreateAlignedLoad(VFuncPtr, CGF.getPointerAlign()); + + CGF.EmitMustTailThunk(MD, getThisValue(CGF), Callee); + + return ThunkFn; +} + +void MicrosoftCXXABI::emitVirtualInheritanceTables(const CXXRecordDecl *RD) { + const VBTableGlobals &VBGlobals = enumerateVBTables(RD); + for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) { + const VPtrInfo *VBT = (*VBGlobals.VBTables)[I]; + llvm::GlobalVariable *GV = VBGlobals.Globals[I]; + if (GV->isDeclaration()) + emitVBTableDefinition(*VBT, RD, GV); + } +} + +llvm::GlobalVariable * +MicrosoftCXXABI::getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD, + llvm::GlobalVariable::LinkageTypes Linkage) { + SmallString<256> OutName; + llvm::raw_svector_ostream Out(OutName); + getMangleContext().mangleCXXVBTable(RD, VBT.MangledPath, Out); + StringRef Name = OutName.str(); + + llvm::ArrayType *VBTableType = + llvm::ArrayType::get(CGM.IntTy, 1 + VBT.ReusingBase->getNumVBases()); + + assert(!CGM.getModule().getNamedGlobal(Name) && + "vbtable with this name already exists: mangling bug?"); + llvm::GlobalVariable *GV = + CGM.CreateOrReplaceCXXRuntimeVariable(Name, VBTableType, Linkage); + GV->setUnnamedAddr(true); + + if (RD->hasAttr<DLLImportAttr>()) + GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass); + else if (RD->hasAttr<DLLExportAttr>()) + GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass); + + if (!GV->hasExternalLinkage()) + emitVBTableDefinition(VBT, RD, GV); + + return GV; +} + +void MicrosoftCXXABI::emitVBTableDefinition(const VPtrInfo &VBT, + const CXXRecordDecl *RD, + llvm::GlobalVariable *GV) const { + const CXXRecordDecl *ReusingBase = VBT.ReusingBase; + + assert(RD->getNumVBases() && ReusingBase->getNumVBases() && + "should only emit vbtables for classes with vbtables"); + + const ASTRecordLayout &BaseLayout = + getContext().getASTRecordLayout(VBT.BaseWithVPtr); + const ASTRecordLayout &DerivedLayout = getContext().getASTRecordLayout(RD); + + SmallVector<llvm::Constant *, 4> Offsets(1 + ReusingBase->getNumVBases(), + nullptr); + + // The offset from ReusingBase's vbptr to itself always leads. + CharUnits VBPtrOffset = BaseLayout.getVBPtrOffset(); + Offsets[0] = llvm::ConstantInt::get(CGM.IntTy, -VBPtrOffset.getQuantity()); + + MicrosoftVTableContext &Context = CGM.getMicrosoftVTableContext(); + for (const auto &I : ReusingBase->vbases()) { + const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl(); + CharUnits Offset = DerivedLayout.getVBaseClassOffset(VBase); + assert(!Offset.isNegative()); + + // Make it relative to the subobject vbptr. + CharUnits CompleteVBPtrOffset = VBT.NonVirtualOffset + VBPtrOffset; + if (VBT.getVBaseWithVPtr()) + CompleteVBPtrOffset += + DerivedLayout.getVBaseClassOffset(VBT.getVBaseWithVPtr()); + Offset -= CompleteVBPtrOffset; + + unsigned VBIndex = Context.getVBTableIndex(ReusingBase, VBase); + assert(Offsets[VBIndex] == nullptr && "The same vbindex seen twice?"); + Offsets[VBIndex] = llvm::ConstantInt::get(CGM.IntTy, Offset.getQuantity()); + } + + assert(Offsets.size() == + cast<llvm::ArrayType>(cast<llvm::PointerType>(GV->getType()) + ->getElementType())->getNumElements()); + llvm::ArrayType *VBTableType = + llvm::ArrayType::get(CGM.IntTy, Offsets.size()); + llvm::Constant *Init = llvm::ConstantArray::get(VBTableType, Offsets); + GV->setInitializer(Init); +} + +llvm::Value *MicrosoftCXXABI::performThisAdjustment(CodeGenFunction &CGF, + Address This, + const ThisAdjustment &TA) { + if (TA.isEmpty()) + return This.getPointer(); + + This = CGF.Builder.CreateElementBitCast(This, CGF.Int8Ty); + + llvm::Value *V; + if (TA.Virtual.isEmpty()) { + V = This.getPointer(); + } else { + assert(TA.Virtual.Microsoft.VtordispOffset < 0); + // Adjust the this argument based on the vtordisp value. + Address VtorDispPtr = + CGF.Builder.CreateConstInBoundsByteGEP(This, + CharUnits::fromQuantity(TA.Virtual.Microsoft.VtordispOffset)); + VtorDispPtr = CGF.Builder.CreateElementBitCast(VtorDispPtr, CGF.Int32Ty); + llvm::Value *VtorDisp = CGF.Builder.CreateLoad(VtorDispPtr, "vtordisp"); + V = CGF.Builder.CreateGEP(This.getPointer(), + CGF.Builder.CreateNeg(VtorDisp)); + + // Unfortunately, having applied the vtordisp means that we no + // longer really have a known alignment for the vbptr step. + // We'll assume the vbptr is pointer-aligned. + + if (TA.Virtual.Microsoft.VBPtrOffset) { + // If the final overrider is defined in a virtual base other than the one + // that holds the vfptr, we have to use a vtordispex thunk which looks up + // the vbtable of the derived class. + assert(TA.Virtual.Microsoft.VBPtrOffset > 0); + assert(TA.Virtual.Microsoft.VBOffsetOffset >= 0); + llvm::Value *VBPtr; + llvm::Value *VBaseOffset = + GetVBaseOffsetFromVBPtr(CGF, Address(V, CGF.getPointerAlign()), + -TA.Virtual.Microsoft.VBPtrOffset, + TA.Virtual.Microsoft.VBOffsetOffset, &VBPtr); + V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset); + } + } + + if (TA.NonVirtual) { + // Non-virtual adjustment might result in a pointer outside the allocated + // object, e.g. if the final overrider class is laid out after the virtual + // base that declares a method in the most derived class. + V = CGF.Builder.CreateConstGEP1_32(V, TA.NonVirtual); + } + + // Don't need to bitcast back, the call CodeGen will handle this. + return V; +} + +llvm::Value * +MicrosoftCXXABI::performReturnAdjustment(CodeGenFunction &CGF, Address Ret, + const ReturnAdjustment &RA) { + if (RA.isEmpty()) + return Ret.getPointer(); + + auto OrigTy = Ret.getType(); + Ret = CGF.Builder.CreateElementBitCast(Ret, CGF.Int8Ty); + + llvm::Value *V = Ret.getPointer(); + if (RA.Virtual.Microsoft.VBIndex) { + assert(RA.Virtual.Microsoft.VBIndex > 0); + int32_t IntSize = CGF.getIntSize().getQuantity(); + llvm::Value *VBPtr; + llvm::Value *VBaseOffset = + GetVBaseOffsetFromVBPtr(CGF, Ret, RA.Virtual.Microsoft.VBPtrOffset, + IntSize * RA.Virtual.Microsoft.VBIndex, &VBPtr); + V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset); + } + + if (RA.NonVirtual) + V = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, V, RA.NonVirtual); + + // Cast back to the original type. + return CGF.Builder.CreateBitCast(V, OrigTy); +} + +bool MicrosoftCXXABI::requiresArrayCookie(const CXXDeleteExpr *expr, + QualType elementType) { + // Microsoft seems to completely ignore the possibility of a + // two-argument usual deallocation function. + return elementType.isDestructedType(); +} + +bool MicrosoftCXXABI::requiresArrayCookie(const CXXNewExpr *expr) { + // Microsoft seems to completely ignore the possibility of a + // two-argument usual deallocation function. + return expr->getAllocatedType().isDestructedType(); +} + +CharUnits MicrosoftCXXABI::getArrayCookieSizeImpl(QualType type) { + // The array cookie is always a size_t; we then pad that out to the + // alignment of the element type. + ASTContext &Ctx = getContext(); + return std::max(Ctx.getTypeSizeInChars(Ctx.getSizeType()), + Ctx.getTypeAlignInChars(type)); +} + +llvm::Value *MicrosoftCXXABI::readArrayCookieImpl(CodeGenFunction &CGF, + Address allocPtr, + CharUnits cookieSize) { + Address numElementsPtr = + CGF.Builder.CreateElementBitCast(allocPtr, CGF.SizeTy); + return CGF.Builder.CreateLoad(numElementsPtr); +} + +Address MicrosoftCXXABI::InitializeArrayCookie(CodeGenFunction &CGF, + Address newPtr, + llvm::Value *numElements, + const CXXNewExpr *expr, + QualType elementType) { + assert(requiresArrayCookie(expr)); + + // The size of the cookie. + CharUnits cookieSize = getArrayCookieSizeImpl(elementType); + + // Compute an offset to the cookie. + Address cookiePtr = newPtr; + + // Write the number of elements into the appropriate slot. + Address numElementsPtr + = CGF.Builder.CreateElementBitCast(cookiePtr, CGF.SizeTy); + CGF.Builder.CreateStore(numElements, numElementsPtr); + + // Finally, compute a pointer to the actual data buffer by skipping + // over the cookie completely. + return CGF.Builder.CreateConstInBoundsByteGEP(newPtr, cookieSize); +} + +static void emitGlobalDtorWithTLRegDtor(CodeGenFunction &CGF, const VarDecl &VD, + llvm::Constant *Dtor, + llvm::Constant *Addr) { + // Create a function which calls the destructor. + llvm::Constant *DtorStub = CGF.createAtExitStub(VD, Dtor, Addr); + + // extern "C" int __tlregdtor(void (*f)(void)); + llvm::FunctionType *TLRegDtorTy = llvm::FunctionType::get( + CGF.IntTy, DtorStub->getType(), /*IsVarArg=*/false); + + llvm::Constant *TLRegDtor = + CGF.CGM.CreateRuntimeFunction(TLRegDtorTy, "__tlregdtor"); + if (llvm::Function *TLRegDtorFn = dyn_cast<llvm::Function>(TLRegDtor)) + TLRegDtorFn->setDoesNotThrow(); + + CGF.EmitNounwindRuntimeCall(TLRegDtor, DtorStub); +} + +void MicrosoftCXXABI::registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D, + llvm::Constant *Dtor, + llvm::Constant *Addr) { + if (D.getTLSKind()) + return emitGlobalDtorWithTLRegDtor(CGF, D, Dtor, Addr); + + // The default behavior is to use atexit. + CGF.registerGlobalDtorWithAtExit(D, Dtor, Addr); +} + +void MicrosoftCXXABI::EmitThreadLocalInitFuncs( + CodeGenModule &CGM, ArrayRef<const VarDecl *> CXXThreadLocals, + ArrayRef<llvm::Function *> CXXThreadLocalInits, + ArrayRef<const VarDecl *> CXXThreadLocalInitVars) { + // This will create a GV in the .CRT$XDU section. It will point to our + // initialization function. The CRT will call all of these function + // pointers at start-up time and, eventually, at thread-creation time. + auto AddToXDU = [&CGM](llvm::Function *InitFunc) { + llvm::GlobalVariable *InitFuncPtr = new llvm::GlobalVariable( + CGM.getModule(), InitFunc->getType(), /*IsConstant=*/true, + llvm::GlobalVariable::InternalLinkage, InitFunc, + Twine(InitFunc->getName(), "$initializer$")); + InitFuncPtr->setSection(".CRT$XDU"); + // This variable has discardable linkage, we have to add it to @llvm.used to + // ensure it won't get discarded. + CGM.addUsedGlobal(InitFuncPtr); + return InitFuncPtr; + }; + + std::vector<llvm::Function *> NonComdatInits; + for (size_t I = 0, E = CXXThreadLocalInitVars.size(); I != E; ++I) { + llvm::GlobalVariable *GV = cast<llvm::GlobalVariable>( + CGM.GetGlobalValue(CGM.getMangledName(CXXThreadLocalInitVars[I]))); + llvm::Function *F = CXXThreadLocalInits[I]; + + // If the GV is already in a comdat group, then we have to join it. + if (llvm::Comdat *C = GV->getComdat()) + AddToXDU(F)->setComdat(C); + else + NonComdatInits.push_back(F); + } + + if (!NonComdatInits.empty()) { + llvm::FunctionType *FTy = + llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false); + llvm::Function *InitFunc = CGM.CreateGlobalInitOrDestructFunction( + FTy, "__tls_init", CGM.getTypes().arrangeNullaryFunction(), + SourceLocation(), /*TLS=*/true); + CodeGenFunction(CGM).GenerateCXXGlobalInitFunc(InitFunc, NonComdatInits); + + AddToXDU(InitFunc); + } +} + +LValue MicrosoftCXXABI::EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, + const VarDecl *VD, + QualType LValType) { + CGF.CGM.ErrorUnsupported(VD, "thread wrappers"); + return LValue(); +} + +static ConstantAddress getInitThreadEpochPtr(CodeGenModule &CGM) { + StringRef VarName("_Init_thread_epoch"); + CharUnits Align = CGM.getIntAlign(); + if (auto *GV = CGM.getModule().getNamedGlobal(VarName)) + return ConstantAddress(GV, Align); + auto *GV = new llvm::GlobalVariable( + CGM.getModule(), CGM.IntTy, + /*Constant=*/false, llvm::GlobalVariable::ExternalLinkage, + /*Initializer=*/nullptr, VarName, + /*InsertBefore=*/nullptr, llvm::GlobalVariable::GeneralDynamicTLSModel); + GV->setAlignment(Align.getQuantity()); + return ConstantAddress(GV, Align); +} + +static llvm::Constant *getInitThreadHeaderFn(CodeGenModule &CGM) { + llvm::FunctionType *FTy = + llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()), + CGM.IntTy->getPointerTo(), /*isVarArg=*/false); + return CGM.CreateRuntimeFunction( + FTy, "_Init_thread_header", + llvm::AttributeSet::get(CGM.getLLVMContext(), + llvm::AttributeSet::FunctionIndex, + llvm::Attribute::NoUnwind)); +} + +static llvm::Constant *getInitThreadFooterFn(CodeGenModule &CGM) { + llvm::FunctionType *FTy = + llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()), + CGM.IntTy->getPointerTo(), /*isVarArg=*/false); + return CGM.CreateRuntimeFunction( + FTy, "_Init_thread_footer", + llvm::AttributeSet::get(CGM.getLLVMContext(), + llvm::AttributeSet::FunctionIndex, + llvm::Attribute::NoUnwind)); +} + +static llvm::Constant *getInitThreadAbortFn(CodeGenModule &CGM) { + llvm::FunctionType *FTy = + llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()), + CGM.IntTy->getPointerTo(), /*isVarArg=*/false); + return CGM.CreateRuntimeFunction( + FTy, "_Init_thread_abort", + llvm::AttributeSet::get(CGM.getLLVMContext(), + llvm::AttributeSet::FunctionIndex, + llvm::Attribute::NoUnwind)); +} + +namespace { +struct ResetGuardBit final : EHScopeStack::Cleanup { + Address Guard; + unsigned GuardNum; + ResetGuardBit(Address Guard, unsigned GuardNum) + : Guard(Guard), GuardNum(GuardNum) {} + + void Emit(CodeGenFunction &CGF, Flags flags) override { + // Reset the bit in the mask so that the static variable may be + // reinitialized. + CGBuilderTy &Builder = CGF.Builder; + llvm::LoadInst *LI = Builder.CreateLoad(Guard); + llvm::ConstantInt *Mask = + llvm::ConstantInt::get(CGF.IntTy, ~(1U << GuardNum)); + Builder.CreateStore(Builder.CreateAnd(LI, Mask), Guard); + } +}; + +struct CallInitThreadAbort final : EHScopeStack::Cleanup { + llvm::Value *Guard; + CallInitThreadAbort(Address Guard) : Guard(Guard.getPointer()) {} + + void Emit(CodeGenFunction &CGF, Flags flags) override { + // Calling _Init_thread_abort will reset the guard's state. + CGF.EmitNounwindRuntimeCall(getInitThreadAbortFn(CGF.CGM), Guard); + } +}; +} + +void MicrosoftCXXABI::EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D, + llvm::GlobalVariable *GV, + bool PerformInit) { + // MSVC only uses guards for static locals. + if (!D.isStaticLocal()) { + assert(GV->hasWeakLinkage() || GV->hasLinkOnceLinkage()); + // GlobalOpt is allowed to discard the initializer, so use linkonce_odr. + llvm::Function *F = CGF.CurFn; + F->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage); + F->setComdat(CGM.getModule().getOrInsertComdat(F->getName())); + CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit); + return; + } + + bool ThreadlocalStatic = D.getTLSKind(); + bool ThreadsafeStatic = getContext().getLangOpts().ThreadsafeStatics; + + // Thread-safe static variables which aren't thread-specific have a + // per-variable guard. + bool HasPerVariableGuard = ThreadsafeStatic && !ThreadlocalStatic; + + CGBuilderTy &Builder = CGF.Builder; + llvm::IntegerType *GuardTy = CGF.Int32Ty; + llvm::ConstantInt *Zero = llvm::ConstantInt::get(GuardTy, 0); + CharUnits GuardAlign = CharUnits::fromQuantity(4); + + // Get the guard variable for this function if we have one already. + GuardInfo *GI = nullptr; + if (ThreadlocalStatic) + GI = &ThreadLocalGuardVariableMap[D.getDeclContext()]; + else if (!ThreadsafeStatic) + GI = &GuardVariableMap[D.getDeclContext()]; + + llvm::GlobalVariable *GuardVar = GI ? GI->Guard : nullptr; + unsigned GuardNum; + if (D.isExternallyVisible()) { + // Externally visible variables have to be numbered in Sema to properly + // handle unreachable VarDecls. + GuardNum = getContext().getStaticLocalNumber(&D); + assert(GuardNum > 0); + GuardNum--; + } else if (HasPerVariableGuard) { + GuardNum = ThreadSafeGuardNumMap[D.getDeclContext()]++; + } else { + // Non-externally visible variables are numbered here in CodeGen. + GuardNum = GI->BitIndex++; + } + + if (!HasPerVariableGuard && GuardNum >= 32) { + if (D.isExternallyVisible()) + ErrorUnsupportedABI(CGF, "more than 32 guarded initializations"); + GuardNum %= 32; + GuardVar = nullptr; + } + + if (!GuardVar) { + // Mangle the name for the guard. + SmallString<256> GuardName; + { + llvm::raw_svector_ostream Out(GuardName); + if (HasPerVariableGuard) + getMangleContext().mangleThreadSafeStaticGuardVariable(&D, GuardNum, + Out); + else + getMangleContext().mangleStaticGuardVariable(&D, Out); + } + + // Create the guard variable with a zero-initializer. Just absorb linkage, + // visibility and dll storage class from the guarded variable. + GuardVar = + new llvm::GlobalVariable(CGM.getModule(), GuardTy, /*isConstant=*/false, + GV->getLinkage(), Zero, GuardName.str()); + GuardVar->setVisibility(GV->getVisibility()); + GuardVar->setDLLStorageClass(GV->getDLLStorageClass()); + GuardVar->setAlignment(GuardAlign.getQuantity()); + if (GuardVar->isWeakForLinker()) + GuardVar->setComdat( + CGM.getModule().getOrInsertComdat(GuardVar->getName())); + if (D.getTLSKind()) + GuardVar->setThreadLocal(true); + if (GI && !HasPerVariableGuard) + GI->Guard = GuardVar; + } + + ConstantAddress GuardAddr(GuardVar, GuardAlign); + + assert(GuardVar->getLinkage() == GV->getLinkage() && + "static local from the same function had different linkage"); + + if (!HasPerVariableGuard) { + // Pseudo code for the test: + // if (!(GuardVar & MyGuardBit)) { + // GuardVar |= MyGuardBit; + // ... initialize the object ...; + // } + + // Test our bit from the guard variable. + llvm::ConstantInt *Bit = llvm::ConstantInt::get(GuardTy, 1U << GuardNum); + llvm::LoadInst *LI = Builder.CreateLoad(GuardAddr); + llvm::Value *IsInitialized = + Builder.CreateICmpNE(Builder.CreateAnd(LI, Bit), Zero); + llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init"); + llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end"); + Builder.CreateCondBr(IsInitialized, EndBlock, InitBlock); + + // Set our bit in the guard variable and emit the initializer and add a global + // destructor if appropriate. + CGF.EmitBlock(InitBlock); + Builder.CreateStore(Builder.CreateOr(LI, Bit), GuardAddr); + CGF.EHStack.pushCleanup<ResetGuardBit>(EHCleanup, GuardAddr, GuardNum); + CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit); + CGF.PopCleanupBlock(); + Builder.CreateBr(EndBlock); + + // Continue. + CGF.EmitBlock(EndBlock); + } else { + // Pseudo code for the test: + // if (TSS > _Init_thread_epoch) { + // _Init_thread_header(&TSS); + // if (TSS == -1) { + // ... initialize the object ...; + // _Init_thread_footer(&TSS); + // } + // } + // + // The algorithm is almost identical to what can be found in the appendix + // found in N2325. + + // This BasicBLock determines whether or not we have any work to do. + llvm::LoadInst *FirstGuardLoad = Builder.CreateLoad(GuardAddr); + FirstGuardLoad->setOrdering(llvm::AtomicOrdering::Unordered); + llvm::LoadInst *InitThreadEpoch = + Builder.CreateLoad(getInitThreadEpochPtr(CGM)); + llvm::Value *IsUninitialized = + Builder.CreateICmpSGT(FirstGuardLoad, InitThreadEpoch); + llvm::BasicBlock *AttemptInitBlock = CGF.createBasicBlock("init.attempt"); + llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end"); + Builder.CreateCondBr(IsUninitialized, AttemptInitBlock, EndBlock); + + // This BasicBlock attempts to determine whether or not this thread is + // responsible for doing the initialization. + CGF.EmitBlock(AttemptInitBlock); + CGF.EmitNounwindRuntimeCall(getInitThreadHeaderFn(CGM), + GuardAddr.getPointer()); + llvm::LoadInst *SecondGuardLoad = Builder.CreateLoad(GuardAddr); + SecondGuardLoad->setOrdering(llvm::AtomicOrdering::Unordered); + llvm::Value *ShouldDoInit = + Builder.CreateICmpEQ(SecondGuardLoad, getAllOnesInt()); + llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init"); + Builder.CreateCondBr(ShouldDoInit, InitBlock, EndBlock); + + // Ok, we ended up getting selected as the initializing thread. + CGF.EmitBlock(InitBlock); + CGF.EHStack.pushCleanup<CallInitThreadAbort>(EHCleanup, GuardAddr); + CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit); + CGF.PopCleanupBlock(); + CGF.EmitNounwindRuntimeCall(getInitThreadFooterFn(CGM), + GuardAddr.getPointer()); + Builder.CreateBr(EndBlock); + + CGF.EmitBlock(EndBlock); + } +} + +bool MicrosoftCXXABI::isZeroInitializable(const MemberPointerType *MPT) { + // Null-ness for function memptrs only depends on the first field, which is + // the function pointer. The rest don't matter, so we can zero initialize. + if (MPT->isMemberFunctionPointer()) + return true; + + // The virtual base adjustment field is always -1 for null, so if we have one + // we can't zero initialize. The field offset is sometimes also -1 if 0 is a + // valid field offset. + const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl(); + MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel(); + return (!MSInheritanceAttr::hasVBTableOffsetField(Inheritance) && + RD->nullFieldOffsetIsZero()); +} + +llvm::Type * +MicrosoftCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) { + const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl(); + MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel(); + llvm::SmallVector<llvm::Type *, 4> fields; + if (MPT->isMemberFunctionPointer()) + fields.push_back(CGM.VoidPtrTy); // FunctionPointerOrVirtualThunk + else + fields.push_back(CGM.IntTy); // FieldOffset + + if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(), + Inheritance)) + fields.push_back(CGM.IntTy); + if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance)) + fields.push_back(CGM.IntTy); + if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance)) + fields.push_back(CGM.IntTy); // VirtualBaseAdjustmentOffset + + if (fields.size() == 1) + return fields[0]; + return llvm::StructType::get(CGM.getLLVMContext(), fields); +} + +void MicrosoftCXXABI:: +GetNullMemberPointerFields(const MemberPointerType *MPT, + llvm::SmallVectorImpl<llvm::Constant *> &fields) { + assert(fields.empty()); + const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl(); + MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel(); + if (MPT->isMemberFunctionPointer()) { + // FunctionPointerOrVirtualThunk + fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy)); + } else { + if (RD->nullFieldOffsetIsZero()) + fields.push_back(getZeroInt()); // FieldOffset + else + fields.push_back(getAllOnesInt()); // FieldOffset + } + + if (MSInheritanceAttr::hasNVOffsetField(MPT->isMemberFunctionPointer(), + Inheritance)) + fields.push_back(getZeroInt()); + if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance)) + fields.push_back(getZeroInt()); + if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance)) + fields.push_back(getAllOnesInt()); +} + +llvm::Constant * +MicrosoftCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) { + llvm::SmallVector<llvm::Constant *, 4> fields; + GetNullMemberPointerFields(MPT, fields); + if (fields.size() == 1) + return fields[0]; + llvm::Constant *Res = llvm::ConstantStruct::getAnon(fields); + assert(Res->getType() == ConvertMemberPointerType(MPT)); + return Res; +} + +llvm::Constant * +MicrosoftCXXABI::EmitFullMemberPointer(llvm::Constant *FirstField, + bool IsMemberFunction, + const CXXRecordDecl *RD, + CharUnits NonVirtualBaseAdjustment, + unsigned VBTableIndex) { + MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel(); + + // Single inheritance class member pointer are represented as scalars instead + // of aggregates. + if (MSInheritanceAttr::hasOnlyOneField(IsMemberFunction, Inheritance)) + return FirstField; + + llvm::SmallVector<llvm::Constant *, 4> fields; + fields.push_back(FirstField); + + if (MSInheritanceAttr::hasNVOffsetField(IsMemberFunction, Inheritance)) + fields.push_back(llvm::ConstantInt::get( + CGM.IntTy, NonVirtualBaseAdjustment.getQuantity())); + + if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance)) { + CharUnits Offs = CharUnits::Zero(); + if (VBTableIndex) + Offs = getContext().getASTRecordLayout(RD).getVBPtrOffset(); + fields.push_back(llvm::ConstantInt::get(CGM.IntTy, Offs.getQuantity())); + } + + // The rest of the fields are adjusted by conversions to a more derived class. + if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance)) + fields.push_back(llvm::ConstantInt::get(CGM.IntTy, VBTableIndex)); + + return llvm::ConstantStruct::getAnon(fields); +} + +llvm::Constant * +MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT, + CharUnits offset) { + const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl(); + if (RD->getMSInheritanceModel() == + MSInheritanceAttr::Keyword_virtual_inheritance) + offset -= getContext().getOffsetOfBaseWithVBPtr(RD); + llvm::Constant *FirstField = + llvm::ConstantInt::get(CGM.IntTy, offset.getQuantity()); + return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/false, RD, + CharUnits::Zero(), /*VBTableIndex=*/0); +} + +llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const APValue &MP, + QualType MPType) { + const MemberPointerType *DstTy = MPType->castAs<MemberPointerType>(); + const ValueDecl *MPD = MP.getMemberPointerDecl(); + if (!MPD) + return EmitNullMemberPointer(DstTy); + + ASTContext &Ctx = getContext(); + ArrayRef<const CXXRecordDecl *> MemberPointerPath = MP.getMemberPointerPath(); + + llvm::Constant *C; + if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MPD)) { + C = EmitMemberFunctionPointer(MD); + } else { + CharUnits FieldOffset = Ctx.toCharUnitsFromBits(Ctx.getFieldOffset(MPD)); + C = EmitMemberDataPointer(DstTy, FieldOffset); + } + + if (!MemberPointerPath.empty()) { + const CXXRecordDecl *SrcRD = cast<CXXRecordDecl>(MPD->getDeclContext()); + const Type *SrcRecTy = Ctx.getTypeDeclType(SrcRD).getTypePtr(); + const MemberPointerType *SrcTy = + Ctx.getMemberPointerType(DstTy->getPointeeType(), SrcRecTy) + ->castAs<MemberPointerType>(); + + bool DerivedMember = MP.isMemberPointerToDerivedMember(); + SmallVector<const CXXBaseSpecifier *, 4> DerivedToBasePath; + const CXXRecordDecl *PrevRD = SrcRD; + for (const CXXRecordDecl *PathElem : MemberPointerPath) { + const CXXRecordDecl *Base = nullptr; + const CXXRecordDecl *Derived = nullptr; + if (DerivedMember) { + Base = PathElem; + Derived = PrevRD; + } else { + Base = PrevRD; + Derived = PathElem; + } + for (const CXXBaseSpecifier &BS : Derived->bases()) + if (BS.getType()->getAsCXXRecordDecl()->getCanonicalDecl() == + Base->getCanonicalDecl()) + DerivedToBasePath.push_back(&BS); + PrevRD = PathElem; + } + assert(DerivedToBasePath.size() == MemberPointerPath.size()); + + CastKind CK = DerivedMember ? CK_DerivedToBaseMemberPointer + : CK_BaseToDerivedMemberPointer; + C = EmitMemberPointerConversion(SrcTy, DstTy, CK, DerivedToBasePath.begin(), + DerivedToBasePath.end(), C); + } + return C; +} + +llvm::Constant * +MicrosoftCXXABI::EmitMemberFunctionPointer(const CXXMethodDecl *MD) { + assert(MD->isInstance() && "Member function must not be static!"); + + MD = MD->getCanonicalDecl(); + CharUnits NonVirtualBaseAdjustment = CharUnits::Zero(); + const CXXRecordDecl *RD = MD->getParent()->getMostRecentDecl(); + CodeGenTypes &Types = CGM.getTypes(); + + unsigned VBTableIndex = 0; + llvm::Constant *FirstField; + const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>(); + if (!MD->isVirtual()) { + llvm::Type *Ty; + // Check whether the function has a computable LLVM signature. + if (Types.isFuncTypeConvertible(FPT)) { + // The function has a computable LLVM signature; use the correct type. + Ty = Types.GetFunctionType(Types.arrangeCXXMethodDeclaration(MD)); + } else { + // Use an arbitrary non-function type to tell GetAddrOfFunction that the + // function type is incomplete. + Ty = CGM.PtrDiffTy; + } + FirstField = CGM.GetAddrOfFunction(MD, Ty); + } else { + auto &VTableContext = CGM.getMicrosoftVTableContext(); + MicrosoftVTableContext::MethodVFTableLocation ML = + VTableContext.getMethodVFTableLocation(MD); + FirstField = EmitVirtualMemPtrThunk(MD, ML); + // Include the vfptr adjustment if the method is in a non-primary vftable. + NonVirtualBaseAdjustment += ML.VFPtrOffset; + if (ML.VBase) + VBTableIndex = VTableContext.getVBTableIndex(RD, ML.VBase) * 4; + } + + if (VBTableIndex == 0 && + RD->getMSInheritanceModel() == + MSInheritanceAttr::Keyword_virtual_inheritance) + NonVirtualBaseAdjustment -= getContext().getOffsetOfBaseWithVBPtr(RD); + + // The rest of the fields are common with data member pointers. + FirstField = llvm::ConstantExpr::getBitCast(FirstField, CGM.VoidPtrTy); + return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/true, RD, + NonVirtualBaseAdjustment, VBTableIndex); +} + +/// Member pointers are the same if they're either bitwise identical *or* both +/// null. Null-ness for function members is determined by the first field, +/// while for data member pointers we must compare all fields. +llvm::Value * +MicrosoftCXXABI::EmitMemberPointerComparison(CodeGenFunction &CGF, + llvm::Value *L, + llvm::Value *R, + const MemberPointerType *MPT, + bool Inequality) { + CGBuilderTy &Builder = CGF.Builder; + + // Handle != comparisons by switching the sense of all boolean operations. + llvm::ICmpInst::Predicate Eq; + llvm::Instruction::BinaryOps And, Or; + if (Inequality) { + Eq = llvm::ICmpInst::ICMP_NE; + And = llvm::Instruction::Or; + Or = llvm::Instruction::And; + } else { + Eq = llvm::ICmpInst::ICMP_EQ; + And = llvm::Instruction::And; + Or = llvm::Instruction::Or; + } + + // If this is a single field member pointer (single inheritance), this is a + // single icmp. + const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl(); + MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel(); + if (MSInheritanceAttr::hasOnlyOneField(MPT->isMemberFunctionPointer(), + Inheritance)) + return Builder.CreateICmp(Eq, L, R); + + // Compare the first field. + llvm::Value *L0 = Builder.CreateExtractValue(L, 0, "lhs.0"); + llvm::Value *R0 = Builder.CreateExtractValue(R, 0, "rhs.0"); + llvm::Value *Cmp0 = Builder.CreateICmp(Eq, L0, R0, "memptr.cmp.first"); + + // Compare everything other than the first field. + llvm::Value *Res = nullptr; + llvm::StructType *LType = cast<llvm::StructType>(L->getType()); + for (unsigned I = 1, E = LType->getNumElements(); I != E; ++I) { + llvm::Value *LF = Builder.CreateExtractValue(L, I); + llvm::Value *RF = Builder.CreateExtractValue(R, I); + llvm::Value *Cmp = Builder.CreateICmp(Eq, LF, RF, "memptr.cmp.rest"); + if (Res) + Res = Builder.CreateBinOp(And, Res, Cmp); + else + Res = Cmp; + } + + // Check if the first field is 0 if this is a function pointer. + if (MPT->isMemberFunctionPointer()) { + // (l1 == r1 && ...) || l0 == 0 + llvm::Value *Zero = llvm::Constant::getNullValue(L0->getType()); + llvm::Value *IsZero = Builder.CreateICmp(Eq, L0, Zero, "memptr.cmp.iszero"); + Res = Builder.CreateBinOp(Or, Res, IsZero); + } + + // Combine the comparison of the first field, which must always be true for + // this comparison to succeeed. + return Builder.CreateBinOp(And, Res, Cmp0, "memptr.cmp"); +} + +llvm::Value * +MicrosoftCXXABI::EmitMemberPointerIsNotNull(CodeGenFunction &CGF, + llvm::Value *MemPtr, + const MemberPointerType *MPT) { + CGBuilderTy &Builder = CGF.Builder; + llvm::SmallVector<llvm::Constant *, 4> fields; + // We only need one field for member functions. + if (MPT->isMemberFunctionPointer()) + fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy)); + else + GetNullMemberPointerFields(MPT, fields); + assert(!fields.empty()); + llvm::Value *FirstField = MemPtr; + if (MemPtr->getType()->isStructTy()) + FirstField = Builder.CreateExtractValue(MemPtr, 0); + llvm::Value *Res = Builder.CreateICmpNE(FirstField, fields[0], "memptr.cmp0"); + + // For function member pointers, we only need to test the function pointer + // field. The other fields if any can be garbage. + if (MPT->isMemberFunctionPointer()) + return Res; + + // Otherwise, emit a series of compares and combine the results. + for (int I = 1, E = fields.size(); I < E; ++I) { + llvm::Value *Field = Builder.CreateExtractValue(MemPtr, I); + llvm::Value *Next = Builder.CreateICmpNE(Field, fields[I], "memptr.cmp"); + Res = Builder.CreateOr(Res, Next, "memptr.tobool"); + } + return Res; +} + +bool MicrosoftCXXABI::MemberPointerConstantIsNull(const MemberPointerType *MPT, + llvm::Constant *Val) { + // Function pointers are null if the pointer in the first field is null. + if (MPT->isMemberFunctionPointer()) { + llvm::Constant *FirstField = Val->getType()->isStructTy() ? + Val->getAggregateElement(0U) : Val; + return FirstField->isNullValue(); + } + + // If it's not a function pointer and it's zero initializable, we can easily + // check zero. + if (isZeroInitializable(MPT) && Val->isNullValue()) + return true; + + // Otherwise, break down all the fields for comparison. Hopefully these + // little Constants are reused, while a big null struct might not be. + llvm::SmallVector<llvm::Constant *, 4> Fields; + GetNullMemberPointerFields(MPT, Fields); + if (Fields.size() == 1) { + assert(Val->getType()->isIntegerTy()); + return Val == Fields[0]; + } + + unsigned I, E; + for (I = 0, E = Fields.size(); I != E; ++I) { + if (Val->getAggregateElement(I) != Fields[I]) + break; + } + return I == E; +} + +llvm::Value * +MicrosoftCXXABI::GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF, + Address This, + llvm::Value *VBPtrOffset, + llvm::Value *VBTableOffset, + llvm::Value **VBPtrOut) { + CGBuilderTy &Builder = CGF.Builder; + // Load the vbtable pointer from the vbptr in the instance. + This = Builder.CreateElementBitCast(This, CGM.Int8Ty); + llvm::Value *VBPtr = + Builder.CreateInBoundsGEP(This.getPointer(), VBPtrOffset, "vbptr"); + if (VBPtrOut) *VBPtrOut = VBPtr; + VBPtr = Builder.CreateBitCast(VBPtr, + CGM.Int32Ty->getPointerTo(0)->getPointerTo(This.getAddressSpace())); + + CharUnits VBPtrAlign; + if (auto CI = dyn_cast<llvm::ConstantInt>(VBPtrOffset)) { + VBPtrAlign = This.getAlignment().alignmentAtOffset( + CharUnits::fromQuantity(CI->getSExtValue())); + } else { + VBPtrAlign = CGF.getPointerAlign(); + } + + llvm::Value *VBTable = Builder.CreateAlignedLoad(VBPtr, VBPtrAlign, "vbtable"); + + // Translate from byte offset to table index. It improves analyzability. + llvm::Value *VBTableIndex = Builder.CreateAShr( + VBTableOffset, llvm::ConstantInt::get(VBTableOffset->getType(), 2), + "vbtindex", /*isExact=*/true); + + // Load an i32 offset from the vb-table. + llvm::Value *VBaseOffs = Builder.CreateInBoundsGEP(VBTable, VBTableIndex); + VBaseOffs = Builder.CreateBitCast(VBaseOffs, CGM.Int32Ty->getPointerTo(0)); + return Builder.CreateAlignedLoad(VBaseOffs, CharUnits::fromQuantity(4), + "vbase_offs"); +} + +// Returns an adjusted base cast to i8*, since we do more address arithmetic on +// it. +llvm::Value *MicrosoftCXXABI::AdjustVirtualBase( + CodeGenFunction &CGF, const Expr *E, const CXXRecordDecl *RD, + Address Base, llvm::Value *VBTableOffset, llvm::Value *VBPtrOffset) { + CGBuilderTy &Builder = CGF.Builder; + Base = Builder.CreateElementBitCast(Base, CGM.Int8Ty); + llvm::BasicBlock *OriginalBB = nullptr; + llvm::BasicBlock *SkipAdjustBB = nullptr; + llvm::BasicBlock *VBaseAdjustBB = nullptr; + + // In the unspecified inheritance model, there might not be a vbtable at all, + // in which case we need to skip the virtual base lookup. If there is a + // vbtable, the first entry is a no-op entry that gives back the original + // base, so look for a virtual base adjustment offset of zero. + if (VBPtrOffset) { + OriginalBB = Builder.GetInsertBlock(); + VBaseAdjustBB = CGF.createBasicBlock("memptr.vadjust"); + SkipAdjustBB = CGF.createBasicBlock("memptr.skip_vadjust"); + llvm::Value *IsVirtual = + Builder.CreateICmpNE(VBTableOffset, getZeroInt(), + "memptr.is_vbase"); + Builder.CreateCondBr(IsVirtual, VBaseAdjustBB, SkipAdjustBB); + CGF.EmitBlock(VBaseAdjustBB); + } + + // If we weren't given a dynamic vbptr offset, RD should be complete and we'll + // know the vbptr offset. + if (!VBPtrOffset) { + CharUnits offs = CharUnits::Zero(); + if (!RD->hasDefinition()) { + DiagnosticsEngine &Diags = CGF.CGM.getDiags(); + unsigned DiagID = Diags.getCustomDiagID( + DiagnosticsEngine::Error, + "member pointer representation requires a " + "complete class type for %0 to perform this expression"); + Diags.Report(E->getExprLoc(), DiagID) << RD << E->getSourceRange(); + } else if (RD->getNumVBases()) + offs = getContext().getASTRecordLayout(RD).getVBPtrOffset(); + VBPtrOffset = llvm::ConstantInt::get(CGM.IntTy, offs.getQuantity()); + } + llvm::Value *VBPtr = nullptr; + llvm::Value *VBaseOffs = + GetVBaseOffsetFromVBPtr(CGF, Base, VBPtrOffset, VBTableOffset, &VBPtr); + llvm::Value *AdjustedBase = Builder.CreateInBoundsGEP(VBPtr, VBaseOffs); + + // Merge control flow with the case where we didn't have to adjust. + if (VBaseAdjustBB) { + Builder.CreateBr(SkipAdjustBB); + CGF.EmitBlock(SkipAdjustBB); + llvm::PHINode *Phi = Builder.CreatePHI(CGM.Int8PtrTy, 2, "memptr.base"); + Phi->addIncoming(Base.getPointer(), OriginalBB); + Phi->addIncoming(AdjustedBase, VBaseAdjustBB); + return Phi; + } + return AdjustedBase; +} + +llvm::Value *MicrosoftCXXABI::EmitMemberDataPointerAddress( + CodeGenFunction &CGF, const Expr *E, Address Base, llvm::Value *MemPtr, + const MemberPointerType *MPT) { + assert(MPT->isMemberDataPointer()); + unsigned AS = Base.getAddressSpace(); + llvm::Type *PType = + CGF.ConvertTypeForMem(MPT->getPointeeType())->getPointerTo(AS); + CGBuilderTy &Builder = CGF.Builder; + const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl(); + MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel(); + + // Extract the fields we need, regardless of model. We'll apply them if we + // have them. + llvm::Value *FieldOffset = MemPtr; + llvm::Value *VirtualBaseAdjustmentOffset = nullptr; + llvm::Value *VBPtrOffset = nullptr; + if (MemPtr->getType()->isStructTy()) { + // We need to extract values. + unsigned I = 0; + FieldOffset = Builder.CreateExtractValue(MemPtr, I++); + if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance)) + VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++); + if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance)) + VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++); + } + + llvm::Value *Addr; + if (VirtualBaseAdjustmentOffset) { + Addr = AdjustVirtualBase(CGF, E, RD, Base, VirtualBaseAdjustmentOffset, + VBPtrOffset); + } else { + Addr = Base.getPointer(); + } + + // Cast to char*. + Addr = Builder.CreateBitCast(Addr, CGF.Int8Ty->getPointerTo(AS)); + + // Apply the offset, which we assume is non-null. + Addr = Builder.CreateInBoundsGEP(Addr, FieldOffset, "memptr.offset"); + + // Cast the address to the appropriate pointer type, adopting the address + // space of the base pointer. + return Builder.CreateBitCast(Addr, PType); +} + +llvm::Value * +MicrosoftCXXABI::EmitMemberPointerConversion(CodeGenFunction &CGF, + const CastExpr *E, + llvm::Value *Src) { + assert(E->getCastKind() == CK_DerivedToBaseMemberPointer || + E->getCastKind() == CK_BaseToDerivedMemberPointer || + E->getCastKind() == CK_ReinterpretMemberPointer); + + // Use constant emission if we can. + if (isa<llvm::Constant>(Src)) + return EmitMemberPointerConversion(E, cast<llvm::Constant>(Src)); + + // We may be adding or dropping fields from the member pointer, so we need + // both types and the inheritance models of both records. + const MemberPointerType *SrcTy = + E->getSubExpr()->getType()->castAs<MemberPointerType>(); + const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>(); + bool IsFunc = SrcTy->isMemberFunctionPointer(); + + // If the classes use the same null representation, reinterpret_cast is a nop. + bool IsReinterpret = E->getCastKind() == CK_ReinterpretMemberPointer; + if (IsReinterpret && IsFunc) + return Src; + + CXXRecordDecl *SrcRD = SrcTy->getMostRecentCXXRecordDecl(); + CXXRecordDecl *DstRD = DstTy->getMostRecentCXXRecordDecl(); + if (IsReinterpret && + SrcRD->nullFieldOffsetIsZero() == DstRD->nullFieldOffsetIsZero()) + return Src; + + CGBuilderTy &Builder = CGF.Builder; + + // Branch past the conversion if Src is null. + llvm::Value *IsNotNull = EmitMemberPointerIsNotNull(CGF, Src, SrcTy); + llvm::Constant *DstNull = EmitNullMemberPointer(DstTy); + + // C++ 5.2.10p9: The null member pointer value is converted to the null member + // pointer value of the destination type. + if (IsReinterpret) { + // For reinterpret casts, sema ensures that src and dst are both functions + // or data and have the same size, which means the LLVM types should match. + assert(Src->getType() == DstNull->getType()); + return Builder.CreateSelect(IsNotNull, Src, DstNull); + } + + llvm::BasicBlock *OriginalBB = Builder.GetInsertBlock(); + llvm::BasicBlock *ConvertBB = CGF.createBasicBlock("memptr.convert"); + llvm::BasicBlock *ContinueBB = CGF.createBasicBlock("memptr.converted"); + Builder.CreateCondBr(IsNotNull, ConvertBB, ContinueBB); + CGF.EmitBlock(ConvertBB); + + llvm::Value *Dst = EmitNonNullMemberPointerConversion( + SrcTy, DstTy, E->getCastKind(), E->path_begin(), E->path_end(), Src, + Builder); + + Builder.CreateBr(ContinueBB); + + // In the continuation, choose between DstNull and Dst. + CGF.EmitBlock(ContinueBB); + llvm::PHINode *Phi = Builder.CreatePHI(DstNull->getType(), 2, "memptr.converted"); + Phi->addIncoming(DstNull, OriginalBB); + Phi->addIncoming(Dst, ConvertBB); + return Phi; +} + +llvm::Value *MicrosoftCXXABI::EmitNonNullMemberPointerConversion( + const MemberPointerType *SrcTy, const MemberPointerType *DstTy, CastKind CK, + CastExpr::path_const_iterator PathBegin, + CastExpr::path_const_iterator PathEnd, llvm::Value *Src, + CGBuilderTy &Builder) { + const CXXRecordDecl *SrcRD = SrcTy->getMostRecentCXXRecordDecl(); + const CXXRecordDecl *DstRD = DstTy->getMostRecentCXXRecordDecl(); + MSInheritanceAttr::Spelling SrcInheritance = SrcRD->getMSInheritanceModel(); + MSInheritanceAttr::Spelling DstInheritance = DstRD->getMSInheritanceModel(); + bool IsFunc = SrcTy->isMemberFunctionPointer(); + bool IsConstant = isa<llvm::Constant>(Src); + + // Decompose src. + llvm::Value *FirstField = Src; + llvm::Value *NonVirtualBaseAdjustment = getZeroInt(); + llvm::Value *VirtualBaseAdjustmentOffset = getZeroInt(); + llvm::Value *VBPtrOffset = getZeroInt(); + if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) { + // We need to extract values. + unsigned I = 0; + FirstField = Builder.CreateExtractValue(Src, I++); + if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance)) + NonVirtualBaseAdjustment = Builder.CreateExtractValue(Src, I++); + if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance)) + VBPtrOffset = Builder.CreateExtractValue(Src, I++); + if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance)) + VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(Src, I++); + } + + bool IsDerivedToBase = (CK == CK_DerivedToBaseMemberPointer); + const MemberPointerType *DerivedTy = IsDerivedToBase ? SrcTy : DstTy; + const CXXRecordDecl *DerivedClass = DerivedTy->getMostRecentCXXRecordDecl(); + + // For data pointers, we adjust the field offset directly. For functions, we + // have a separate field. + llvm::Value *&NVAdjustField = IsFunc ? NonVirtualBaseAdjustment : FirstField; + + // The virtual inheritance model has a quirk: the virtual base table is always + // referenced when dereferencing a member pointer even if the member pointer + // is non-virtual. This is accounted for by adjusting the non-virtual offset + // to point backwards to the top of the MDC from the first VBase. Undo this + // adjustment to normalize the member pointer. + llvm::Value *SrcVBIndexEqZero = + Builder.CreateICmpEQ(VirtualBaseAdjustmentOffset, getZeroInt()); + if (SrcInheritance == MSInheritanceAttr::Keyword_virtual_inheritance) { + if (int64_t SrcOffsetToFirstVBase = + getContext().getOffsetOfBaseWithVBPtr(SrcRD).getQuantity()) { + llvm::Value *UndoSrcAdjustment = Builder.CreateSelect( + SrcVBIndexEqZero, + llvm::ConstantInt::get(CGM.IntTy, SrcOffsetToFirstVBase), + getZeroInt()); + NVAdjustField = Builder.CreateNSWAdd(NVAdjustField, UndoSrcAdjustment); + } + } + + // A non-zero vbindex implies that we are dealing with a source member in a + // floating virtual base in addition to some non-virtual offset. If the + // vbindex is zero, we are dealing with a source that exists in a non-virtual, + // fixed, base. The difference between these two cases is that the vbindex + + // nvoffset *always* point to the member regardless of what context they are + // evaluated in so long as the vbindex is adjusted. A member inside a fixed + // base requires explicit nv adjustment. + llvm::Constant *BaseClassOffset = llvm::ConstantInt::get( + CGM.IntTy, + CGM.computeNonVirtualBaseClassOffset(DerivedClass, PathBegin, PathEnd) + .getQuantity()); + + llvm::Value *NVDisp; + if (IsDerivedToBase) + NVDisp = Builder.CreateNSWSub(NVAdjustField, BaseClassOffset, "adj"); + else + NVDisp = Builder.CreateNSWAdd(NVAdjustField, BaseClassOffset, "adj"); + + NVAdjustField = Builder.CreateSelect(SrcVBIndexEqZero, NVDisp, getZeroInt()); + + // Update the vbindex to an appropriate value in the destination because + // SrcRD's vbtable might not be a strict prefix of the one in DstRD. + llvm::Value *DstVBIndexEqZero = SrcVBIndexEqZero; + if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance) && + MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance)) { + if (llvm::GlobalVariable *VDispMap = + getAddrOfVirtualDisplacementMap(SrcRD, DstRD)) { + llvm::Value *VBIndex = Builder.CreateExactUDiv( + VirtualBaseAdjustmentOffset, llvm::ConstantInt::get(CGM.IntTy, 4)); + if (IsConstant) { + llvm::Constant *Mapping = VDispMap->getInitializer(); + VirtualBaseAdjustmentOffset = + Mapping->getAggregateElement(cast<llvm::Constant>(VBIndex)); + } else { + llvm::Value *Idxs[] = {getZeroInt(), VBIndex}; + VirtualBaseAdjustmentOffset = + Builder.CreateAlignedLoad(Builder.CreateInBoundsGEP(VDispMap, Idxs), + CharUnits::fromQuantity(4)); + } + + DstVBIndexEqZero = + Builder.CreateICmpEQ(VirtualBaseAdjustmentOffset, getZeroInt()); + } + } + + // Set the VBPtrOffset to zero if the vbindex is zero. Otherwise, initialize + // it to the offset of the vbptr. + if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance)) { + llvm::Value *DstVBPtrOffset = llvm::ConstantInt::get( + CGM.IntTy, + getContext().getASTRecordLayout(DstRD).getVBPtrOffset().getQuantity()); + VBPtrOffset = + Builder.CreateSelect(DstVBIndexEqZero, getZeroInt(), DstVBPtrOffset); + } + + // Likewise, apply a similar adjustment so that dereferencing the member + // pointer correctly accounts for the distance between the start of the first + // virtual base and the top of the MDC. + if (DstInheritance == MSInheritanceAttr::Keyword_virtual_inheritance) { + if (int64_t DstOffsetToFirstVBase = + getContext().getOffsetOfBaseWithVBPtr(DstRD).getQuantity()) { + llvm::Value *DoDstAdjustment = Builder.CreateSelect( + DstVBIndexEqZero, + llvm::ConstantInt::get(CGM.IntTy, DstOffsetToFirstVBase), + getZeroInt()); + NVAdjustField = Builder.CreateNSWSub(NVAdjustField, DoDstAdjustment); + } + } + + // Recompose dst from the null struct and the adjusted fields from src. + llvm::Value *Dst; + if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance)) { + Dst = FirstField; + } else { + Dst = llvm::UndefValue::get(ConvertMemberPointerType(DstTy)); + unsigned Idx = 0; + Dst = Builder.CreateInsertValue(Dst, FirstField, Idx++); + if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance)) + Dst = Builder.CreateInsertValue(Dst, NonVirtualBaseAdjustment, Idx++); + if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance)) + Dst = Builder.CreateInsertValue(Dst, VBPtrOffset, Idx++); + if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance)) + Dst = Builder.CreateInsertValue(Dst, VirtualBaseAdjustmentOffset, Idx++); + } + return Dst; +} + +llvm::Constant * +MicrosoftCXXABI::EmitMemberPointerConversion(const CastExpr *E, + llvm::Constant *Src) { + const MemberPointerType *SrcTy = + E->getSubExpr()->getType()->castAs<MemberPointerType>(); + const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>(); + + CastKind CK = E->getCastKind(); + + return EmitMemberPointerConversion(SrcTy, DstTy, CK, E->path_begin(), + E->path_end(), Src); +} + +llvm::Constant *MicrosoftCXXABI::EmitMemberPointerConversion( + const MemberPointerType *SrcTy, const MemberPointerType *DstTy, CastKind CK, + CastExpr::path_const_iterator PathBegin, + CastExpr::path_const_iterator PathEnd, llvm::Constant *Src) { + assert(CK == CK_DerivedToBaseMemberPointer || + CK == CK_BaseToDerivedMemberPointer || + CK == CK_ReinterpretMemberPointer); + // If src is null, emit a new null for dst. We can't return src because dst + // might have a new representation. + if (MemberPointerConstantIsNull(SrcTy, Src)) + return EmitNullMemberPointer(DstTy); + + // We don't need to do anything for reinterpret_casts of non-null member + // pointers. We should only get here when the two type representations have + // the same size. + if (CK == CK_ReinterpretMemberPointer) + return Src; + + CGBuilderTy Builder(CGM, CGM.getLLVMContext()); + auto *Dst = cast<llvm::Constant>(EmitNonNullMemberPointerConversion( + SrcTy, DstTy, CK, PathBegin, PathEnd, Src, Builder)); + + return Dst; +} + +llvm::Value *MicrosoftCXXABI::EmitLoadOfMemberFunctionPointer( + CodeGenFunction &CGF, const Expr *E, Address This, + llvm::Value *&ThisPtrForCall, llvm::Value *MemPtr, + const MemberPointerType *MPT) { + assert(MPT->isMemberFunctionPointer()); + const FunctionProtoType *FPT = + MPT->getPointeeType()->castAs<FunctionProtoType>(); + const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl(); + llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType( + CGM.getTypes().arrangeCXXMethodType(RD, FPT, /*FD=*/nullptr)); + CGBuilderTy &Builder = CGF.Builder; + + MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel(); + + // Extract the fields we need, regardless of model. We'll apply them if we + // have them. + llvm::Value *FunctionPointer = MemPtr; + llvm::Value *NonVirtualBaseAdjustment = nullptr; + llvm::Value *VirtualBaseAdjustmentOffset = nullptr; + llvm::Value *VBPtrOffset = nullptr; + if (MemPtr->getType()->isStructTy()) { + // We need to extract values. + unsigned I = 0; + FunctionPointer = Builder.CreateExtractValue(MemPtr, I++); + if (MSInheritanceAttr::hasNVOffsetField(MPT, Inheritance)) + NonVirtualBaseAdjustment = Builder.CreateExtractValue(MemPtr, I++); + if (MSInheritanceAttr::hasVBPtrOffsetField(Inheritance)) + VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++); + if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance)) + VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++); + } + + if (VirtualBaseAdjustmentOffset) { + ThisPtrForCall = AdjustVirtualBase(CGF, E, RD, This, + VirtualBaseAdjustmentOffset, VBPtrOffset); + } else { + ThisPtrForCall = This.getPointer(); + } + + if (NonVirtualBaseAdjustment) { + // Apply the adjustment and cast back to the original struct type. + llvm::Value *Ptr = Builder.CreateBitCast(ThisPtrForCall, CGF.Int8PtrTy); + Ptr = Builder.CreateInBoundsGEP(Ptr, NonVirtualBaseAdjustment); + ThisPtrForCall = Builder.CreateBitCast(Ptr, ThisPtrForCall->getType(), + "this.adjusted"); + } + + return Builder.CreateBitCast(FunctionPointer, FTy->getPointerTo()); +} + +CGCXXABI *clang::CodeGen::CreateMicrosoftCXXABI(CodeGenModule &CGM) { + return new MicrosoftCXXABI(CGM); +} + +// MS RTTI Overview: +// The run time type information emitted by cl.exe contains 5 distinct types of +// structures. Many of them reference each other. +// +// TypeInfo: Static classes that are returned by typeid. +// +// CompleteObjectLocator: Referenced by vftables. They contain information +// required for dynamic casting, including OffsetFromTop. They also contain +// a reference to the TypeInfo for the type and a reference to the +// CompleteHierarchyDescriptor for the type. +// +// ClassHieararchyDescriptor: Contains information about a class hierarchy. +// Used during dynamic_cast to walk a class hierarchy. References a base +// class array and the size of said array. +// +// BaseClassArray: Contains a list of classes in a hierarchy. BaseClassArray is +// somewhat of a misnomer because the most derived class is also in the list +// as well as multiple copies of virtual bases (if they occur multiple times +// in the hiearchy.) The BaseClassArray contains one BaseClassDescriptor for +// every path in the hierarchy, in pre-order depth first order. Note, we do +// not declare a specific llvm type for BaseClassArray, it's merely an array +// of BaseClassDescriptor pointers. +// +// BaseClassDescriptor: Contains information about a class in a class hierarchy. +// BaseClassDescriptor is also somewhat of a misnomer for the same reason that +// BaseClassArray is. It contains information about a class within a +// hierarchy such as: is this base is ambiguous and what is its offset in the +// vbtable. The names of the BaseClassDescriptors have all of their fields +// mangled into them so they can be aggressively deduplicated by the linker. + +static llvm::GlobalVariable *getTypeInfoVTable(CodeGenModule &CGM) { + StringRef MangledName("\01??_7type_info@@6B@"); + if (auto VTable = CGM.getModule().getNamedGlobal(MangledName)) + return VTable; + return new llvm::GlobalVariable(CGM.getModule(), CGM.Int8PtrTy, + /*Constant=*/true, + llvm::GlobalVariable::ExternalLinkage, + /*Initializer=*/nullptr, MangledName); +} + +namespace { + +/// \brief A Helper struct that stores information about a class in a class +/// hierarchy. The information stored in these structs struct is used during +/// the generation of ClassHierarchyDescriptors and BaseClassDescriptors. +// During RTTI creation, MSRTTIClasses are stored in a contiguous array with +// implicit depth first pre-order tree connectivity. getFirstChild and +// getNextSibling allow us to walk the tree efficiently. +struct MSRTTIClass { + enum { + IsPrivateOnPath = 1 | 8, + IsAmbiguous = 2, + IsPrivate = 4, + IsVirtual = 16, + HasHierarchyDescriptor = 64 + }; + MSRTTIClass(const CXXRecordDecl *RD) : RD(RD) {} + uint32_t initialize(const MSRTTIClass *Parent, + const CXXBaseSpecifier *Specifier); + + MSRTTIClass *getFirstChild() { return this + 1; } + static MSRTTIClass *getNextChild(MSRTTIClass *Child) { + return Child + 1 + Child->NumBases; + } + + const CXXRecordDecl *RD, *VirtualRoot; + uint32_t Flags, NumBases, OffsetInVBase; +}; + +/// \brief Recursively initialize the base class array. +uint32_t MSRTTIClass::initialize(const MSRTTIClass *Parent, + const CXXBaseSpecifier *Specifier) { + Flags = HasHierarchyDescriptor; + if (!Parent) { + VirtualRoot = nullptr; + OffsetInVBase = 0; + } else { + if (Specifier->getAccessSpecifier() != AS_public) + Flags |= IsPrivate | IsPrivateOnPath; + if (Specifier->isVirtual()) { + Flags |= IsVirtual; + VirtualRoot = RD; + OffsetInVBase = 0; + } else { + if (Parent->Flags & IsPrivateOnPath) + Flags |= IsPrivateOnPath; + VirtualRoot = Parent->VirtualRoot; + OffsetInVBase = Parent->OffsetInVBase + RD->getASTContext() + .getASTRecordLayout(Parent->RD).getBaseClassOffset(RD).getQuantity(); + } + } + NumBases = 0; + MSRTTIClass *Child = getFirstChild(); + for (const CXXBaseSpecifier &Base : RD->bases()) { + NumBases += Child->initialize(this, &Base) + 1; + Child = getNextChild(Child); + } + return NumBases; +} + +static llvm::GlobalValue::LinkageTypes getLinkageForRTTI(QualType Ty) { + switch (Ty->getLinkage()) { + case NoLinkage: + case InternalLinkage: + case UniqueExternalLinkage: + return llvm::GlobalValue::InternalLinkage; + + case VisibleNoLinkage: + case ExternalLinkage: + return llvm::GlobalValue::LinkOnceODRLinkage; + } + llvm_unreachable("Invalid linkage!"); +} + +/// \brief An ephemeral helper class for building MS RTTI types. It caches some +/// calls to the module and information about the most derived class in a +/// hierarchy. +struct MSRTTIBuilder { + enum { + HasBranchingHierarchy = 1, + HasVirtualBranchingHierarchy = 2, + HasAmbiguousBases = 4 + }; + + MSRTTIBuilder(MicrosoftCXXABI &ABI, const CXXRecordDecl *RD) + : CGM(ABI.CGM), Context(CGM.getContext()), + VMContext(CGM.getLLVMContext()), Module(CGM.getModule()), RD(RD), + Linkage(getLinkageForRTTI(CGM.getContext().getTagDeclType(RD))), + ABI(ABI) {} + + llvm::GlobalVariable *getBaseClassDescriptor(const MSRTTIClass &Classes); + llvm::GlobalVariable * + getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes); + llvm::GlobalVariable *getClassHierarchyDescriptor(); + llvm::GlobalVariable *getCompleteObjectLocator(const VPtrInfo *Info); + + CodeGenModule &CGM; + ASTContext &Context; + llvm::LLVMContext &VMContext; + llvm::Module &Module; + const CXXRecordDecl *RD; + llvm::GlobalVariable::LinkageTypes Linkage; + MicrosoftCXXABI &ABI; +}; + +} // namespace + +/// \brief Recursively serializes a class hierarchy in pre-order depth first +/// order. +static void serializeClassHierarchy(SmallVectorImpl<MSRTTIClass> &Classes, + const CXXRecordDecl *RD) { + Classes.push_back(MSRTTIClass(RD)); + for (const CXXBaseSpecifier &Base : RD->bases()) + serializeClassHierarchy(Classes, Base.getType()->getAsCXXRecordDecl()); +} + +/// \brief Find ambiguity among base classes. +static void +detectAmbiguousBases(SmallVectorImpl<MSRTTIClass> &Classes) { + llvm::SmallPtrSet<const CXXRecordDecl *, 8> VirtualBases; + llvm::SmallPtrSet<const CXXRecordDecl *, 8> UniqueBases; + llvm::SmallPtrSet<const CXXRecordDecl *, 8> AmbiguousBases; + for (MSRTTIClass *Class = &Classes.front(); Class <= &Classes.back();) { + if ((Class->Flags & MSRTTIClass::IsVirtual) && + !VirtualBases.insert(Class->RD).second) { + Class = MSRTTIClass::getNextChild(Class); + continue; + } + if (!UniqueBases.insert(Class->RD).second) + AmbiguousBases.insert(Class->RD); + Class++; + } + if (AmbiguousBases.empty()) + return; + for (MSRTTIClass &Class : Classes) + if (AmbiguousBases.count(Class.RD)) + Class.Flags |= MSRTTIClass::IsAmbiguous; +} + +llvm::GlobalVariable *MSRTTIBuilder::getClassHierarchyDescriptor() { + SmallString<256> MangledName; + { + llvm::raw_svector_ostream Out(MangledName); + ABI.getMangleContext().mangleCXXRTTIClassHierarchyDescriptor(RD, Out); + } + + // Check to see if we've already declared this ClassHierarchyDescriptor. + if (auto CHD = Module.getNamedGlobal(MangledName)) + return CHD; + + // Serialize the class hierarchy and initialize the CHD Fields. + SmallVector<MSRTTIClass, 8> Classes; + serializeClassHierarchy(Classes, RD); + Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr); + detectAmbiguousBases(Classes); + int Flags = 0; + for (auto Class : Classes) { + if (Class.RD->getNumBases() > 1) + Flags |= HasBranchingHierarchy; + // Note: cl.exe does not calculate "HasAmbiguousBases" correctly. We + // believe the field isn't actually used. + if (Class.Flags & MSRTTIClass::IsAmbiguous) + Flags |= HasAmbiguousBases; + } + if ((Flags & HasBranchingHierarchy) && RD->getNumVBases() != 0) + Flags |= HasVirtualBranchingHierarchy; + // These gep indices are used to get the address of the first element of the + // base class array. + llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0), + llvm::ConstantInt::get(CGM.IntTy, 0)}; + + // Forward-declare the class hierarchy descriptor + auto Type = ABI.getClassHierarchyDescriptorType(); + auto CHD = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage, + /*Initializer=*/nullptr, + MangledName); + if (CHD->isWeakForLinker()) + CHD->setComdat(CGM.getModule().getOrInsertComdat(CHD->getName())); + + auto *Bases = getBaseClassArray(Classes); + + // Initialize the base class ClassHierarchyDescriptor. + llvm::Constant *Fields[] = { + llvm::ConstantInt::get(CGM.IntTy, 0), // Unknown + llvm::ConstantInt::get(CGM.IntTy, Flags), + llvm::ConstantInt::get(CGM.IntTy, Classes.size()), + ABI.getImageRelativeConstant(llvm::ConstantExpr::getInBoundsGetElementPtr( + Bases->getValueType(), Bases, + llvm::ArrayRef<llvm::Value *>(GEPIndices))), + }; + CHD->setInitializer(llvm::ConstantStruct::get(Type, Fields)); + return CHD; +} + +llvm::GlobalVariable * +MSRTTIBuilder::getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes) { + SmallString<256> MangledName; + { + llvm::raw_svector_ostream Out(MangledName); + ABI.getMangleContext().mangleCXXRTTIBaseClassArray(RD, Out); + } + + // Forward-declare the base class array. + // cl.exe pads the base class array with 1 (in 32 bit mode) or 4 (in 64 bit + // mode) bytes of padding. We provide a pointer sized amount of padding by + // adding +1 to Classes.size(). The sections have pointer alignment and are + // marked pick-any so it shouldn't matter. + llvm::Type *PtrType = ABI.getImageRelativeType( + ABI.getBaseClassDescriptorType()->getPointerTo()); + auto *ArrType = llvm::ArrayType::get(PtrType, Classes.size() + 1); + auto *BCA = + new llvm::GlobalVariable(Module, ArrType, + /*Constant=*/true, Linkage, + /*Initializer=*/nullptr, MangledName); + if (BCA->isWeakForLinker()) + BCA->setComdat(CGM.getModule().getOrInsertComdat(BCA->getName())); + + // Initialize the BaseClassArray. + SmallVector<llvm::Constant *, 8> BaseClassArrayData; + for (MSRTTIClass &Class : Classes) + BaseClassArrayData.push_back( + ABI.getImageRelativeConstant(getBaseClassDescriptor(Class))); + BaseClassArrayData.push_back(llvm::Constant::getNullValue(PtrType)); + BCA->setInitializer(llvm::ConstantArray::get(ArrType, BaseClassArrayData)); + return BCA; +} + +llvm::GlobalVariable * +MSRTTIBuilder::getBaseClassDescriptor(const MSRTTIClass &Class) { + // Compute the fields for the BaseClassDescriptor. They are computed up front + // because they are mangled into the name of the object. + uint32_t OffsetInVBTable = 0; + int32_t VBPtrOffset = -1; + if (Class.VirtualRoot) { + auto &VTableContext = CGM.getMicrosoftVTableContext(); + OffsetInVBTable = VTableContext.getVBTableIndex(RD, Class.VirtualRoot) * 4; + VBPtrOffset = Context.getASTRecordLayout(RD).getVBPtrOffset().getQuantity(); + } + + SmallString<256> MangledName; + { + llvm::raw_svector_ostream Out(MangledName); + ABI.getMangleContext().mangleCXXRTTIBaseClassDescriptor( + Class.RD, Class.OffsetInVBase, VBPtrOffset, OffsetInVBTable, + Class.Flags, Out); + } + + // Check to see if we've already declared this object. + if (auto BCD = Module.getNamedGlobal(MangledName)) + return BCD; + + // Forward-declare the base class descriptor. + auto Type = ABI.getBaseClassDescriptorType(); + auto BCD = + new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage, + /*Initializer=*/nullptr, MangledName); + if (BCD->isWeakForLinker()) + BCD->setComdat(CGM.getModule().getOrInsertComdat(BCD->getName())); + + // Initialize the BaseClassDescriptor. + llvm::Constant *Fields[] = { + ABI.getImageRelativeConstant( + ABI.getAddrOfRTTIDescriptor(Context.getTypeDeclType(Class.RD))), + llvm::ConstantInt::get(CGM.IntTy, Class.NumBases), + llvm::ConstantInt::get(CGM.IntTy, Class.OffsetInVBase), + llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset), + llvm::ConstantInt::get(CGM.IntTy, OffsetInVBTable), + llvm::ConstantInt::get(CGM.IntTy, Class.Flags), + ABI.getImageRelativeConstant( + MSRTTIBuilder(ABI, Class.RD).getClassHierarchyDescriptor()), + }; + BCD->setInitializer(llvm::ConstantStruct::get(Type, Fields)); + return BCD; +} + +llvm::GlobalVariable * +MSRTTIBuilder::getCompleteObjectLocator(const VPtrInfo *Info) { + SmallString<256> MangledName; + { + llvm::raw_svector_ostream Out(MangledName); + ABI.getMangleContext().mangleCXXRTTICompleteObjectLocator(RD, Info->MangledPath, Out); + } + + // Check to see if we've already computed this complete object locator. + if (auto COL = Module.getNamedGlobal(MangledName)) + return COL; + + // Compute the fields of the complete object locator. + int OffsetToTop = Info->FullOffsetInMDC.getQuantity(); + int VFPtrOffset = 0; + // The offset includes the vtordisp if one exists. + if (const CXXRecordDecl *VBase = Info->getVBaseWithVPtr()) + if (Context.getASTRecordLayout(RD) + .getVBaseOffsetsMap() + .find(VBase) + ->second.hasVtorDisp()) + VFPtrOffset = Info->NonVirtualOffset.getQuantity() + 4; + + // Forward-declare the complete object locator. + llvm::StructType *Type = ABI.getCompleteObjectLocatorType(); + auto COL = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage, + /*Initializer=*/nullptr, MangledName); + + // Initialize the CompleteObjectLocator. + llvm::Constant *Fields[] = { + llvm::ConstantInt::get(CGM.IntTy, ABI.isImageRelative()), + llvm::ConstantInt::get(CGM.IntTy, OffsetToTop), + llvm::ConstantInt::get(CGM.IntTy, VFPtrOffset), + ABI.getImageRelativeConstant( + CGM.GetAddrOfRTTIDescriptor(Context.getTypeDeclType(RD))), + ABI.getImageRelativeConstant(getClassHierarchyDescriptor()), + ABI.getImageRelativeConstant(COL), + }; + llvm::ArrayRef<llvm::Constant *> FieldsRef(Fields); + if (!ABI.isImageRelative()) + FieldsRef = FieldsRef.drop_back(); + COL->setInitializer(llvm::ConstantStruct::get(Type, FieldsRef)); + if (COL->isWeakForLinker()) + COL->setComdat(CGM.getModule().getOrInsertComdat(COL->getName())); + return COL; +} + +static QualType decomposeTypeForEH(ASTContext &Context, QualType T, + bool &IsConst, bool &IsVolatile) { + T = Context.getExceptionObjectType(T); + + // C++14 [except.handle]p3: + // A handler is a match for an exception object of type E if [...] + // - the handler is of type cv T or const T& where T is a pointer type and + // E is a pointer type that can be converted to T by [...] + // - a qualification conversion + IsConst = false; + IsVolatile = false; + QualType PointeeType = T->getPointeeType(); + if (!PointeeType.isNull()) { + IsConst = PointeeType.isConstQualified(); + IsVolatile = PointeeType.isVolatileQualified(); + } + + // Member pointer types like "const int A::*" are represented by having RTTI + // for "int A::*" and separately storing the const qualifier. + if (const auto *MPTy = T->getAs<MemberPointerType>()) + T = Context.getMemberPointerType(PointeeType.getUnqualifiedType(), + MPTy->getClass()); + + // Pointer types like "const int * const *" are represented by having RTTI + // for "const int **" and separately storing the const qualifier. + if (T->isPointerType()) + T = Context.getPointerType(PointeeType.getUnqualifiedType()); + + return T; +} + +CatchTypeInfo +MicrosoftCXXABI::getAddrOfCXXCatchHandlerType(QualType Type, + QualType CatchHandlerType) { + // TypeDescriptors for exceptions never have qualified pointer types, + // qualifiers are stored seperately in order to support qualification + // conversions. + bool IsConst, IsVolatile; + Type = decomposeTypeForEH(getContext(), Type, IsConst, IsVolatile); + + bool IsReference = CatchHandlerType->isReferenceType(); + + uint32_t Flags = 0; + if (IsConst) + Flags |= 1; + if (IsVolatile) + Flags |= 2; + if (IsReference) + Flags |= 8; + + return CatchTypeInfo{getAddrOfRTTIDescriptor(Type)->stripPointerCasts(), + Flags}; +} + +/// \brief Gets a TypeDescriptor. Returns a llvm::Constant * rather than a +/// llvm::GlobalVariable * because different type descriptors have different +/// types, and need to be abstracted. They are abstracting by casting the +/// address to an Int8PtrTy. +llvm::Constant *MicrosoftCXXABI::getAddrOfRTTIDescriptor(QualType Type) { + SmallString<256> MangledName; + { + llvm::raw_svector_ostream Out(MangledName); + getMangleContext().mangleCXXRTTI(Type, Out); + } + + // Check to see if we've already declared this TypeDescriptor. + if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName)) + return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy); + + // Compute the fields for the TypeDescriptor. + SmallString<256> TypeInfoString; + { + llvm::raw_svector_ostream Out(TypeInfoString); + getMangleContext().mangleCXXRTTIName(Type, Out); + } + + // Declare and initialize the TypeDescriptor. + llvm::Constant *Fields[] = { + getTypeInfoVTable(CGM), // VFPtr + llvm::ConstantPointerNull::get(CGM.Int8PtrTy), // Runtime data + llvm::ConstantDataArray::getString(CGM.getLLVMContext(), TypeInfoString)}; + llvm::StructType *TypeDescriptorType = + getTypeDescriptorType(TypeInfoString); + auto *Var = new llvm::GlobalVariable( + CGM.getModule(), TypeDescriptorType, /*Constant=*/false, + getLinkageForRTTI(Type), + llvm::ConstantStruct::get(TypeDescriptorType, Fields), + MangledName); + if (Var->isWeakForLinker()) + Var->setComdat(CGM.getModule().getOrInsertComdat(Var->getName())); + return llvm::ConstantExpr::getBitCast(Var, CGM.Int8PtrTy); +} + +/// \brief Gets or a creates a Microsoft CompleteObjectLocator. +llvm::GlobalVariable * +MicrosoftCXXABI::getMSCompleteObjectLocator(const CXXRecordDecl *RD, + const VPtrInfo *Info) { + return MSRTTIBuilder(*this, RD).getCompleteObjectLocator(Info); +} + +static void emitCXXConstructor(CodeGenModule &CGM, + const CXXConstructorDecl *ctor, + StructorType ctorType) { + // There are no constructor variants, always emit the complete destructor. + llvm::Function *Fn = CGM.codegenCXXStructor(ctor, StructorType::Complete); + CGM.maybeSetTrivialComdat(*ctor, *Fn); +} + +static void emitCXXDestructor(CodeGenModule &CGM, const CXXDestructorDecl *dtor, + StructorType dtorType) { + // The complete destructor is equivalent to the base destructor for + // classes with no virtual bases, so try to emit it as an alias. + if (!dtor->getParent()->getNumVBases() && + (dtorType == StructorType::Complete || dtorType == StructorType::Base)) { + bool ProducedAlias = !CGM.TryEmitDefinitionAsAlias( + GlobalDecl(dtor, Dtor_Complete), GlobalDecl(dtor, Dtor_Base), true); + if (ProducedAlias) { + if (dtorType == StructorType::Complete) + return; + if (dtor->isVirtual()) + CGM.getVTables().EmitThunks(GlobalDecl(dtor, Dtor_Complete)); + } + } + + // The base destructor is equivalent to the base destructor of its + // base class if there is exactly one non-virtual base class with a + // non-trivial destructor, there are no fields with a non-trivial + // destructor, and the body of the destructor is trivial. + if (dtorType == StructorType::Base && !CGM.TryEmitBaseDestructorAsAlias(dtor)) + return; + + llvm::Function *Fn = CGM.codegenCXXStructor(dtor, dtorType); + if (Fn->isWeakForLinker()) + Fn->setComdat(CGM.getModule().getOrInsertComdat(Fn->getName())); +} + +void MicrosoftCXXABI::emitCXXStructor(const CXXMethodDecl *MD, + StructorType Type) { + if (auto *CD = dyn_cast<CXXConstructorDecl>(MD)) { + emitCXXConstructor(CGM, CD, Type); + return; + } + emitCXXDestructor(CGM, cast<CXXDestructorDecl>(MD), Type); +} + +llvm::Function * +MicrosoftCXXABI::getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD, + CXXCtorType CT) { + assert(CT == Ctor_CopyingClosure || CT == Ctor_DefaultClosure); + + // Calculate the mangled name. + SmallString<256> ThunkName; + llvm::raw_svector_ostream Out(ThunkName); + getMangleContext().mangleCXXCtor(CD, CT, Out); + + // If the thunk has been generated previously, just return it. + if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName)) + return cast<llvm::Function>(GV); + + // Create the llvm::Function. + const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeMSCtorClosure(CD, CT); + llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo); + const CXXRecordDecl *RD = CD->getParent(); + QualType RecordTy = getContext().getRecordType(RD); + llvm::Function *ThunkFn = llvm::Function::Create( + ThunkTy, getLinkageForRTTI(RecordTy), ThunkName.str(), &CGM.getModule()); + ThunkFn->setCallingConv(static_cast<llvm::CallingConv::ID>( + FnInfo.getEffectiveCallingConvention())); + if (ThunkFn->isWeakForLinker()) + ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName())); + bool IsCopy = CT == Ctor_CopyingClosure; + + // Start codegen. + CodeGenFunction CGF(CGM); + CGF.CurGD = GlobalDecl(CD, Ctor_Complete); + + // Build FunctionArgs. + FunctionArgList FunctionArgs; + + // A constructor always starts with a 'this' pointer as its first argument. + buildThisParam(CGF, FunctionArgs); + + // Following the 'this' pointer is a reference to the source object that we + // are copying from. + ImplicitParamDecl SrcParam( + getContext(), nullptr, SourceLocation(), &getContext().Idents.get("src"), + getContext().getLValueReferenceType(RecordTy, + /*SpelledAsLValue=*/true)); + if (IsCopy) + FunctionArgs.push_back(&SrcParam); + + // Constructors for classes which utilize virtual bases have an additional + // parameter which indicates whether or not it is being delegated to by a more + // derived constructor. + ImplicitParamDecl IsMostDerived(getContext(), nullptr, SourceLocation(), + &getContext().Idents.get("is_most_derived"), + getContext().IntTy); + // Only add the parameter to the list if thie class has virtual bases. + if (RD->getNumVBases() > 0) + FunctionArgs.push_back(&IsMostDerived); + + // Start defining the function. + CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo, + FunctionArgs, CD->getLocation(), SourceLocation()); + EmitThisParam(CGF); + llvm::Value *This = getThisValue(CGF); + + llvm::Value *SrcVal = + IsCopy ? CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(&SrcParam), "src") + : nullptr; + + CallArgList Args; + + // Push the this ptr. + Args.add(RValue::get(This), CD->getThisType(getContext())); + + // Push the src ptr. + if (SrcVal) + Args.add(RValue::get(SrcVal), SrcParam.getType()); + + // Add the rest of the default arguments. + std::vector<Stmt *> ArgVec; + for (unsigned I = IsCopy ? 1 : 0, E = CD->getNumParams(); I != E; ++I) { + Stmt *DefaultArg = getContext().getDefaultArgExprForConstructor(CD, I); + assert(DefaultArg && "sema forgot to instantiate default args"); + ArgVec.push_back(DefaultArg); + } + + CodeGenFunction::RunCleanupsScope Cleanups(CGF); + + const auto *FPT = CD->getType()->castAs<FunctionProtoType>(); + CGF.EmitCallArgs(Args, FPT, llvm::makeArrayRef(ArgVec), CD, IsCopy ? 1 : 0); + + // Insert any ABI-specific implicit constructor arguments. + unsigned ExtraArgs = addImplicitConstructorArgs(CGF, CD, Ctor_Complete, + /*ForVirtualBase=*/false, + /*Delegating=*/false, Args); + + // Call the destructor with our arguments. + llvm::Value *CalleeFn = CGM.getAddrOfCXXStructor(CD, StructorType::Complete); + const CGFunctionInfo &CalleeInfo = CGM.getTypes().arrangeCXXConstructorCall( + Args, CD, Ctor_Complete, ExtraArgs); + CGF.EmitCall(CalleeInfo, CalleeFn, ReturnValueSlot(), Args, CD); + + Cleanups.ForceCleanup(); + + // Emit the ret instruction, remove any temporary instructions created for the + // aid of CodeGen. + CGF.FinishFunction(SourceLocation()); + + return ThunkFn; +} + +llvm::Constant *MicrosoftCXXABI::getCatchableType(QualType T, + uint32_t NVOffset, + int32_t VBPtrOffset, + uint32_t VBIndex) { + assert(!T->isReferenceType()); + + CXXRecordDecl *RD = T->getAsCXXRecordDecl(); + const CXXConstructorDecl *CD = + RD ? CGM.getContext().getCopyConstructorForExceptionObject(RD) : nullptr; + CXXCtorType CT = Ctor_Complete; + if (CD) + if (!hasDefaultCXXMethodCC(getContext(), CD) || CD->getNumParams() != 1) + CT = Ctor_CopyingClosure; + + uint32_t Size = getContext().getTypeSizeInChars(T).getQuantity(); + SmallString<256> MangledName; + { + llvm::raw_svector_ostream Out(MangledName); + getMangleContext().mangleCXXCatchableType(T, CD, CT, Size, NVOffset, + VBPtrOffset, VBIndex, Out); + } + if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName)) + return getImageRelativeConstant(GV); + + // The TypeDescriptor is used by the runtime to determine if a catch handler + // is appropriate for the exception object. + llvm::Constant *TD = getImageRelativeConstant(getAddrOfRTTIDescriptor(T)); + + // The runtime is responsible for calling the copy constructor if the + // exception is caught by value. + llvm::Constant *CopyCtor; + if (CD) { + if (CT == Ctor_CopyingClosure) + CopyCtor = getAddrOfCXXCtorClosure(CD, Ctor_CopyingClosure); + else + CopyCtor = CGM.getAddrOfCXXStructor(CD, StructorType::Complete); + + CopyCtor = llvm::ConstantExpr::getBitCast(CopyCtor, CGM.Int8PtrTy); + } else { + CopyCtor = llvm::Constant::getNullValue(CGM.Int8PtrTy); + } + CopyCtor = getImageRelativeConstant(CopyCtor); + + bool IsScalar = !RD; + bool HasVirtualBases = false; + bool IsStdBadAlloc = false; // std::bad_alloc is special for some reason. + QualType PointeeType = T; + if (T->isPointerType()) + PointeeType = T->getPointeeType(); + if (const CXXRecordDecl *RD = PointeeType->getAsCXXRecordDecl()) { + HasVirtualBases = RD->getNumVBases() > 0; + if (IdentifierInfo *II = RD->getIdentifier()) + IsStdBadAlloc = II->isStr("bad_alloc") && RD->isInStdNamespace(); + } + + // Encode the relevant CatchableType properties into the Flags bitfield. + // FIXME: Figure out how bits 2 or 8 can get set. + uint32_t Flags = 0; + if (IsScalar) + Flags |= 1; + if (HasVirtualBases) + Flags |= 4; + if (IsStdBadAlloc) + Flags |= 16; + + llvm::Constant *Fields[] = { + llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags + TD, // TypeDescriptor + llvm::ConstantInt::get(CGM.IntTy, NVOffset), // NonVirtualAdjustment + llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset), // OffsetToVBPtr + llvm::ConstantInt::get(CGM.IntTy, VBIndex), // VBTableIndex + llvm::ConstantInt::get(CGM.IntTy, Size), // Size + CopyCtor // CopyCtor + }; + llvm::StructType *CTType = getCatchableTypeType(); + auto *GV = new llvm::GlobalVariable( + CGM.getModule(), CTType, /*Constant=*/true, getLinkageForRTTI(T), + llvm::ConstantStruct::get(CTType, Fields), MangledName); + GV->setUnnamedAddr(true); + GV->setSection(".xdata"); + if (GV->isWeakForLinker()) + GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName())); + return getImageRelativeConstant(GV); +} + +llvm::GlobalVariable *MicrosoftCXXABI::getCatchableTypeArray(QualType T) { + assert(!T->isReferenceType()); + + // See if we've already generated a CatchableTypeArray for this type before. + llvm::GlobalVariable *&CTA = CatchableTypeArrays[T]; + if (CTA) + return CTA; + + // Ensure that we don't have duplicate entries in our CatchableTypeArray by + // using a SmallSetVector. Duplicates may arise due to virtual bases + // occurring more than once in the hierarchy. + llvm::SmallSetVector<llvm::Constant *, 2> CatchableTypes; + + // C++14 [except.handle]p3: + // A handler is a match for an exception object of type E if [...] + // - the handler is of type cv T or cv T& and T is an unambiguous public + // base class of E, or + // - the handler is of type cv T or const T& where T is a pointer type and + // E is a pointer type that can be converted to T by [...] + // - a standard pointer conversion (4.10) not involving conversions to + // pointers to private or protected or ambiguous classes + const CXXRecordDecl *MostDerivedClass = nullptr; + bool IsPointer = T->isPointerType(); + if (IsPointer) + MostDerivedClass = T->getPointeeType()->getAsCXXRecordDecl(); + else + MostDerivedClass = T->getAsCXXRecordDecl(); + + // Collect all the unambiguous public bases of the MostDerivedClass. + if (MostDerivedClass) { + const ASTContext &Context = getContext(); + const ASTRecordLayout &MostDerivedLayout = + Context.getASTRecordLayout(MostDerivedClass); + MicrosoftVTableContext &VTableContext = CGM.getMicrosoftVTableContext(); + SmallVector<MSRTTIClass, 8> Classes; + serializeClassHierarchy(Classes, MostDerivedClass); + Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr); + detectAmbiguousBases(Classes); + for (const MSRTTIClass &Class : Classes) { + // Skip any ambiguous or private bases. + if (Class.Flags & + (MSRTTIClass::IsPrivateOnPath | MSRTTIClass::IsAmbiguous)) + continue; + // Write down how to convert from a derived pointer to a base pointer. + uint32_t OffsetInVBTable = 0; + int32_t VBPtrOffset = -1; + if (Class.VirtualRoot) { + OffsetInVBTable = + VTableContext.getVBTableIndex(MostDerivedClass, Class.VirtualRoot)*4; + VBPtrOffset = MostDerivedLayout.getVBPtrOffset().getQuantity(); + } + + // Turn our record back into a pointer if the exception object is a + // pointer. + QualType RTTITy = QualType(Class.RD->getTypeForDecl(), 0); + if (IsPointer) + RTTITy = Context.getPointerType(RTTITy); + CatchableTypes.insert(getCatchableType(RTTITy, Class.OffsetInVBase, + VBPtrOffset, OffsetInVBTable)); + } + } + + // C++14 [except.handle]p3: + // A handler is a match for an exception object of type E if + // - The handler is of type cv T or cv T& and E and T are the same type + // (ignoring the top-level cv-qualifiers) + CatchableTypes.insert(getCatchableType(T)); + + // C++14 [except.handle]p3: + // A handler is a match for an exception object of type E if + // - the handler is of type cv T or const T& where T is a pointer type and + // E is a pointer type that can be converted to T by [...] + // - a standard pointer conversion (4.10) not involving conversions to + // pointers to private or protected or ambiguous classes + // + // C++14 [conv.ptr]p2: + // A prvalue of type "pointer to cv T," where T is an object type, can be + // converted to a prvalue of type "pointer to cv void". + if (IsPointer && T->getPointeeType()->isObjectType()) + CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy)); + + // C++14 [except.handle]p3: + // A handler is a match for an exception object of type E if [...] + // - the handler is of type cv T or const T& where T is a pointer or + // pointer to member type and E is std::nullptr_t. + // + // We cannot possibly list all possible pointer types here, making this + // implementation incompatible with the standard. However, MSVC includes an + // entry for pointer-to-void in this case. Let's do the same. + if (T->isNullPtrType()) + CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy)); + + uint32_t NumEntries = CatchableTypes.size(); + llvm::Type *CTType = + getImageRelativeType(getCatchableTypeType()->getPointerTo()); + llvm::ArrayType *AT = llvm::ArrayType::get(CTType, NumEntries); + llvm::StructType *CTAType = getCatchableTypeArrayType(NumEntries); + llvm::Constant *Fields[] = { + llvm::ConstantInt::get(CGM.IntTy, NumEntries), // NumEntries + llvm::ConstantArray::get( + AT, llvm::makeArrayRef(CatchableTypes.begin(), + CatchableTypes.end())) // CatchableTypes + }; + SmallString<256> MangledName; + { + llvm::raw_svector_ostream Out(MangledName); + getMangleContext().mangleCXXCatchableTypeArray(T, NumEntries, Out); + } + CTA = new llvm::GlobalVariable( + CGM.getModule(), CTAType, /*Constant=*/true, getLinkageForRTTI(T), + llvm::ConstantStruct::get(CTAType, Fields), MangledName); + CTA->setUnnamedAddr(true); + CTA->setSection(".xdata"); + if (CTA->isWeakForLinker()) + CTA->setComdat(CGM.getModule().getOrInsertComdat(CTA->getName())); + return CTA; +} + +llvm::GlobalVariable *MicrosoftCXXABI::getThrowInfo(QualType T) { + bool IsConst, IsVolatile; + T = decomposeTypeForEH(getContext(), T, IsConst, IsVolatile); + + // The CatchableTypeArray enumerates the various (CV-unqualified) types that + // the exception object may be caught as. + llvm::GlobalVariable *CTA = getCatchableTypeArray(T); + // The first field in a CatchableTypeArray is the number of CatchableTypes. + // This is used as a component of the mangled name which means that we need to + // know what it is in order to see if we have previously generated the + // ThrowInfo. + uint32_t NumEntries = + cast<llvm::ConstantInt>(CTA->getInitializer()->getAggregateElement(0U)) + ->getLimitedValue(); + + SmallString<256> MangledName; + { + llvm::raw_svector_ostream Out(MangledName); + getMangleContext().mangleCXXThrowInfo(T, IsConst, IsVolatile, NumEntries, + Out); + } + + // Reuse a previously generated ThrowInfo if we have generated an appropriate + // one before. + if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName)) + return GV; + + // The RTTI TypeDescriptor uses an unqualified type but catch clauses must + // be at least as CV qualified. Encode this requirement into the Flags + // bitfield. + uint32_t Flags = 0; + if (IsConst) + Flags |= 1; + if (IsVolatile) + Flags |= 2; + + // The cleanup-function (a destructor) must be called when the exception + // object's lifetime ends. + llvm::Constant *CleanupFn = llvm::Constant::getNullValue(CGM.Int8PtrTy); + if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl()) + if (CXXDestructorDecl *DtorD = RD->getDestructor()) + if (!DtorD->isTrivial()) + CleanupFn = llvm::ConstantExpr::getBitCast( + CGM.getAddrOfCXXStructor(DtorD, StructorType::Complete), + CGM.Int8PtrTy); + // This is unused as far as we can tell, initialize it to null. + llvm::Constant *ForwardCompat = + getImageRelativeConstant(llvm::Constant::getNullValue(CGM.Int8PtrTy)); + llvm::Constant *PointerToCatchableTypes = getImageRelativeConstant( + llvm::ConstantExpr::getBitCast(CTA, CGM.Int8PtrTy)); + llvm::StructType *TIType = getThrowInfoType(); + llvm::Constant *Fields[] = { + llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags + getImageRelativeConstant(CleanupFn), // CleanupFn + ForwardCompat, // ForwardCompat + PointerToCatchableTypes // CatchableTypeArray + }; + auto *GV = new llvm::GlobalVariable( + CGM.getModule(), TIType, /*Constant=*/true, getLinkageForRTTI(T), + llvm::ConstantStruct::get(TIType, Fields), StringRef(MangledName)); + GV->setUnnamedAddr(true); + GV->setSection(".xdata"); + if (GV->isWeakForLinker()) + GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName())); + return GV; +} + +void MicrosoftCXXABI::emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) { + const Expr *SubExpr = E->getSubExpr(); + QualType ThrowType = SubExpr->getType(); + // The exception object lives on the stack and it's address is passed to the + // runtime function. + Address AI = CGF.CreateMemTemp(ThrowType); + CGF.EmitAnyExprToMem(SubExpr, AI, ThrowType.getQualifiers(), + /*IsInit=*/true); + + // The so-called ThrowInfo is used to describe how the exception object may be + // caught. + llvm::GlobalVariable *TI = getThrowInfo(ThrowType); + + // Call into the runtime to throw the exception. + llvm::Value *Args[] = { + CGF.Builder.CreateBitCast(AI.getPointer(), CGM.Int8PtrTy), + TI + }; + CGF.EmitNoreturnRuntimeCallOrInvoke(getThrowFn(), Args); +} |
