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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 | 3090 |
1 files changed, 3090 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..c067fab --- /dev/null +++ b/contrib/llvm/tools/clang/lib/CodeGen/MicrosoftCXXABI.cpp @@ -0,0 +1,3090 @@ +//===--- 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 "CGVTables.h" +#include "CodeGenModule.h" +#include "clang/AST/Decl.h" +#include "clang/AST/DeclCXX.h" +#include "clang/AST/VTableBuilder.h" +#include "llvm/ADT/StringExtras.h" +#include "llvm/ADT/StringSet.h" +#include "llvm/IR/CallSite.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) {} + + 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; } + + 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; + } + + StringRef GetPureVirtualCallName() override { return "_purecall"; } + StringRef GetDeletedVirtualCallName() override { return "_purecall"; } + + void emitVirtualObjectDelete(CodeGenFunction &CGF, const CXXDeleteExpr *DE, + llvm::Value *Ptr, QualType ElementType, + const CXXDestructorDecl *Dtor) override; + + void emitRethrow(CodeGenFunction &CGF, bool isNoReturn) override; + + llvm::GlobalVariable *getMSCompleteObjectLocator(const CXXRecordDecl *RD, + const VPtrInfo *Info); + + llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) override; + + bool shouldTypeidBeNullChecked(bool IsDeref, QualType SrcRecordTy) override; + void EmitBadTypeidCall(CodeGenFunction &CGF) override; + llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy, + llvm::Value *ThisPtr, + llvm::Type *StdTypeInfoPtrTy) override; + + bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr, + QualType SrcRecordTy) override; + + llvm::Value *EmitDynamicCastCall(CodeGenFunction &CGF, llvm::Value *Value, + QualType SrcRecordTy, QualType DestTy, + QualType DestRecordTy, + llvm::BasicBlock *CastEnd) override; + + llvm::Value *EmitDynamicCastToVoid(CodeGenFunction &CGF, llvm::Value *Value, + QualType SrcRecordTy, + QualType DestTy) override; + + bool EmitBadCastCall(CodeGenFunction &CGF) override; + + llvm::Value * + GetVirtualBaseClassOffset(CodeGenFunction &CGF, llvm::Value *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(); + } + + llvm::Value * + adjustThisArgumentForVirtualFunctionCall(CodeGenFunction &CGF, GlobalDecl GD, + llvm::Value *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, llvm::Value *This) override; + + void emitVTableDefinitions(CodeGenVTables &CGVT, + const CXXRecordDecl *RD) override; + + llvm::Value *getVTableAddressPointInStructor( + CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, + BaseSubobject Base, const CXXRecordDecl *NearestVBase, + bool &NeedsVirtualOffset) 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, + llvm::Value *This, + llvm::Type *Ty) override; + + llvm::Value *EmitVirtualDestructorCall(CodeGenFunction &CGF, + const CXXDestructorDecl *Dtor, + CXXDtorType DtorType, + llvm::Value *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)), + CGM.getContext().IntTy); + } + + void emitVirtualInheritanceTables(const CXXRecordDecl *RD) override; + + llvm::GlobalVariable * + getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD, + llvm::GlobalVariable::LinkageTypes Linkage); + + 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, llvm::Value *This, + const ThisAdjustment &TA) override; + + llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret, + const ReturnAdjustment &RA) override; + + void EmitThreadLocalInitFuncs( + CodeGenModule &CGM, + ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>> + CXXThreadLocals, + ArrayRef<llvm::Function *> CXXThreadLocalInits, + ArrayRef<llvm::GlobalVariable *> 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; + llvm::Value *InitializeArrayCookie(CodeGenFunction &CGF, + llvm::Value *NewPtr, + llvm::Value *NumElements, + const CXXNewExpr *expr, + QualType ElementType) override; + llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF, + llvm::Value *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; + + 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); + } + + llvm::Constant *getConstantOrZeroInt(llvm::Constant *C) { + return C ? C : getZeroInt(); + } + + llvm::Value *getValueOrZeroInt(llvm::Value *C) { + return C ? C : getZeroInt(); + } + + 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, + llvm::Value *Base, + llvm::Value *VBPtrOffset, + llvm::Value *VBTableOffset, + llvm::Value **VBPtr = nullptr); + + llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF, + llvm::Value *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); + } + + /// \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, llvm::Value *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); + + llvm::Constant *BuildMemberPointer(const CXXRecordDecl *RD, + const CXXMethodDecl *MD, + CharUnits NonVirtualBaseAdjustment); + + 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>(); + } + + bool isTypeInfoCalculable(QualType Ty) const override { + if (!CGCXXABI::isTypeInfoCalculable(Ty)) + return false; + if (const auto *MPT = Ty->getAs<MemberPointerType>()) { + const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl(); + if (!RD->hasAttr<MSInheritanceAttr>()) + return false; + } + return true; + } + + llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT) override; + + llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT, + CharUnits offset) override; + llvm::Constant *EmitMemberPointer(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, + llvm::Value *Base, llvm::Value *MemPtr, + const MemberPointerType *MPT) override; + + llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF, + const CastExpr *E, + llvm::Value *Src) override; + + llvm::Constant *EmitMemberPointerConversion(const CastExpr *E, + llvm::Constant *Src) override; + + llvm::Value * + EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, const Expr *E, + llvm::Value *&This, llvm::Value *MemPtr, + const MemberPointerType *MPT) override; + + void emitCXXStructor(const CXXMethodDecl *MD, StructorType Type) 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<size_t, llvm::StructType *> TypeDescriptorTypeMap; + llvm::StructType *BaseClassDescriptorType; + llvm::StructType *ClassHierarchyDescriptorType; + llvm::StructType *CompleteObjectLocatorType; +}; + +} + +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, + llvm::Value *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); +} + +static llvm::Function *getRethrowFn(CodeGenModule &CGM) { + // _CxxThrowException takes two pointer width arguments: a value and a context + // object which points to a TypeInfo object. + llvm::Type *ArgTypes[] = {CGM.Int8PtrTy, CGM.Int8PtrTy}; + llvm::FunctionType *FTy = + llvm::FunctionType::get(CGM.VoidTy, ArgTypes, 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; +} + +void MicrosoftCXXABI::emitRethrow(CodeGenFunction &CGF, bool isNoReturn) { + llvm::Value *Args[] = {llvm::ConstantPointerNull::get(CGM.Int8PtrTy), + llvm::ConstantPointerNull::get(CGM.Int8PtrTy)}; + auto *Fn = getRethrowFn(CGM); + if (isNoReturn) + CGF.EmitNoreturnRuntimeCallOrInvoke(Fn, Args); + else + CGF.EmitRuntimeCallOrInvoke(Fn, Args); +} + +/// \brief Gets the offset to the virtual base that contains the vfptr for +/// MS-ABI polymorphic types. +static llvm::Value *getPolymorphicOffset(CodeGenFunction &CGF, + const CXXRecordDecl *RD, + llvm::Value *Value) { + const ASTContext &Context = RD->getASTContext(); + for (const CXXBaseSpecifier &Base : RD->vbases()) + if (Context.getASTRecordLayout(Base.getType()->getAsCXXRecordDecl()) + .hasExtendableVFPtr()) + return CGF.CGM.getCXXABI().GetVirtualBaseClassOffset( + CGF, Value, RD, Base.getType()->getAsCXXRecordDecl()); + llvm_unreachable("One of our vbases should be polymorphic."); +} + +static std::pair<llvm::Value *, llvm::Value *> +performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value, + QualType SrcRecordTy) { + Value = CGF.Builder.CreateBitCast(Value, CGF.Int8PtrTy); + const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl(); + + if (CGF.getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr()) + return std::make_pair(Value, llvm::ConstantInt::get(CGF.Int32Ty, 0)); + + // Perform a base adjustment. + llvm::Value *Offset = getPolymorphicOffset(CGF, SrcDecl, Value); + Value = CGF.Builder.CreateInBoundsGEP(Value, Offset); + Offset = CGF.Builder.CreateTrunc(Offset, CGF.Int32Ty); + return std::make_pair(Value, Offset); +} + +bool MicrosoftCXXABI::shouldTypeidBeNullChecked(bool IsDeref, + QualType SrcRecordTy) { + const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl(); + return IsDeref && + !CGM.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, + llvm::Value *ThisPtr, + llvm::Type *StdTypeInfoPtrTy) { + llvm::Value *Offset; + std::tie(ThisPtr, Offset) = performBaseAdjustment(CGF, ThisPtr, SrcRecordTy); + return CGF.Builder.CreateBitCast( + emitRTtypeidCall(CGF, ThisPtr).getInstruction(), StdTypeInfoPtrTy); +} + +bool MicrosoftCXXABI::shouldDynamicCastCallBeNullChecked(bool SrcIsPtr, + QualType SrcRecordTy) { + const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl(); + return SrcIsPtr && + !CGM.getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr(); +} + +llvm::Value *MicrosoftCXXABI::EmitDynamicCastCall( + CodeGenFunction &CGF, llvm::Value *Value, 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(Value, Offset) = performBaseAdjustment(CGF, Value, SrcRecordTy); + + // 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[] = { + Value, Offset, SrcRTTI, DestRTTI, + llvm::ConstantInt::get(CGF.Int32Ty, DestTy->isReferenceType())}; + Value = CGF.EmitRuntimeCallOrInvoke(Function, Args).getInstruction(); + return CGF.Builder.CreateBitCast(Value, DestLTy); +} + +llvm::Value * +MicrosoftCXXABI::EmitDynamicCastToVoid(CodeGenFunction &CGF, llvm::Value *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}; + return CGF.EmitRuntimeCall(Function, Args); +} + +bool MicrosoftCXXABI::EmitBadCastCall(CodeGenFunction &CGF) { + return false; +} + +llvm::Value *MicrosoftCXXABI::GetVirtualBaseClassOffset( + CodeGenFunction &CGF, llvm::Value *This, const CXXRecordDecl *ClassDecl, + const CXXRecordDecl *BaseClassDecl) { + int64_t VBPtrChars = + getContext().getASTRecordLayout(ClassDecl).getVBPtrOffset().getQuantity(); + llvm::Value *VBPtrOffset = llvm::ConstantInt::get(CGM.PtrDiffTy, VBPtrChars); + CharUnits IntSize = getContext().getTypeSizeInChars(getContext().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; + + if (FI.isInstanceMethod()) { + // If it's an instance method, aggregates are always returned indirectly via + // the second parameter. + FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*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(0, /*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 = + cast<llvm::PointerType>(getThisValue(CGF)->getType())->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, getThisValue(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.CreateStore(VtorDispValue, VtorDispPtr); + } +} + +void MicrosoftCXXABI::EmitCXXConstructors(const CXXConstructorDecl *D) { + // There's only one constructor type in this ABI. + CGM.EmitGlobal(GlobalDecl(D, Ctor_Complete)); +} + +void MicrosoftCXXABI::EmitVBPtrStores(CodeGenFunction &CGF, + const CXXRecordDecl *RD) { + llvm::Value *ThisInt8Ptr = + CGF.Builder.CreateBitCast(getThisValue(CGF), CGM.Int8PtrTy, "this.int8"); + const ASTRecordLayout &Layout = CGM.getContext().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 = + CGM.getContext().getASTRecordLayout(VBT->BaseWithVPtr); + CharUnits Offs = VBT->NonVirtualOffset; + Offs += SubobjectLayout.getVBPtrOffset(); + if (VBT->getVBaseWithVPtr()) + Offs += Layout.getVBaseClassOffset(VBT->getVBaseWithVPtr()); + llvm::Value *VBPtr = + CGF.Builder.CreateConstInBoundsGEP1_64(ThisInt8Ptr, Offs.getQuantity()); + llvm::Value *GVPtr = CGF.Builder.CreateConstInBoundsGEP2_32(GV, 0, 0); + VBPtr = CGF.Builder.CreateBitCast(VBPtr, GVPtr->getType()->getPointerTo(0), + "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(CGM.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, CGM.getContext().IntTy); + else + ArgTys.push_back(CGM.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 = + CGM.getContext().getASTRecordLayout(MD->getParent()); + Adjustment += DerivedLayout.getVBaseClassOffset(ML.VBase); + } + + return Adjustment; +} + +llvm::Value *MicrosoftCXXABI::adjustThisArgumentForVirtualFunctionCall( + CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *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; + + unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace(); + llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS); + This = CGF.Builder.CreateBitCast(This, charPtrTy); + assert(Adjustment.isPositive()); + return CGF.Builder.CreateConstGEP1_32(This, Adjustment.getQuantity()); + } + + 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); + + unsigned AS = cast<llvm::PointerType>(This->getType())->getAddressSpace(); + llvm::Type *charPtrTy = CGF.Int8Ty->getPointerTo(AS); + 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(); + + if (ML.VBase) { + This = CGF.Builder.CreateBitCast(This, charPtrTy); + llvm::Value *VBaseOffset = + GetVirtualBaseClassOffset(CGF, This, MD->getParent(), ML.VBase); + This = CGF.Builder.CreateInBoundsGEP(This, VBaseOffset); + } + if (!StaticOffset.isZero()) { + assert(StaticOffset.isPositive()); + This = CGF.Builder.CreateBitCast(This, charPtrTy); + 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. + This = CGF.Builder.CreateConstGEP1_32(This, StaticOffset.getQuantity()); + } else { + This = CGF.Builder.CreateConstInBoundsGEP1_32(This, + StaticOffset.getQuantity()); + } + } + return This; +} + +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(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, llvm::Value *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, + /*ImplicitParam=*/nullptr, + /*ImplicitParamTy=*/QualType(), nullptr, + getFromDtorType(Type)); +} + +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); + } +} + +llvm::Value *MicrosoftCXXABI::getVTableAddressPointInStructor( + CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, BaseSubobject Base, + const CXXRecordDecl *NearestVBase, bool &NeedsVirtualOffset) { + NeedsVirtualOffset = (NearestVBase != nullptr); + + (void)getAddrOfVTable(VTableClass, Base.getBaseOffset()); + VFTableIdTy ID(VTableClass, Base.getBaseOffset()); + llvm::GlobalValue *VTableAddressPoint = VFTablesMap[ID]; + if (!VTableAddressPoint) { + assert(Base.getBase()->getNumVBases() && + !CGM.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::getVTableAddressPointForConstExpr( + BaseSubobject Base, const CXXRecordDecl *VTableClass) { + (void)getAddrOfVTable(VTableClass, Base.getBaseOffset()); + VFTableIdTy ID(VTableClass, Base.getBaseOffset()); + llvm::GlobalValue *VFTable = VFTablesMap[ID]; + 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 + } + + for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) { + if (VFPtrs[J]->FullOffsetInMDC != VPtrOffset) + continue; + SmallString<256> VFTableName; + mangleVFTableName(getMangleContext(), RD, VFPtrs[J], VFTableName); + StringRef VTableName = VFTableName; + + uint64_t NumVTableSlots = + VTContext.getVFTableLayout(RD, VFPtrs[J]->FullOffsetInMDC) + .getNumVTableComponents(); + llvm::GlobalValue::LinkageTypes VTableLinkage = + llvm::GlobalValue::ExternalLinkage; + llvm::ArrayType *VTableType = + llvm::ArrayType::get(CGM.Int8PtrTy, NumVTableSlots); + if (getContext().getLangOpts().RTTIData) { + VTableLinkage = llvm::GlobalValue::PrivateLinkage; + VTableName = ""; + } + + VTable = CGM.getModule().getNamedGlobal(VFTableName); + if (!VTable) { + // 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); + + // 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 (getContext().getLangOpts().RTTIData && + !RD->hasAttr<DLLImportAttr>()) { + 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, GEPIndices); + // The symbol for the VFTable is an alias to the GEP. It is + // transparent, to other modules, what the nature of this symbol is; all + // that matters is that the alias be the address of the first virtual + // method. + VFTable = llvm::GlobalAlias::create( + cast<llvm::SequentialType>(VTableGEP->getType())->getElementType(), + /*AddressSpace=*/0, llvm::GlobalValue::ExternalLinkage, + VFTableName.str(), VTableGEP, &CGM.getModule()); + } 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. + VTable->setName(VFTableName.str()); + } + + VFTable->setUnnamedAddr(true); + if (RD->hasAttr<DLLImportAttr>()) + VFTable->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass); + else if (RD->hasAttr<DLLExportAttr>()) + VFTable->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass); + + llvm::GlobalValue::LinkageTypes VFTableLinkage = CGM.getVTableLinkage(RD); + if (VFTable != VTable) { + if (llvm::GlobalValue::isAvailableExternallyLinkage(VFTableLinkage)) { + // AvailableExternally implies that we grabbed the data from another + // executable. No need to stick the alias in a Comdat. + } else if (llvm::GlobalValue::isInternalLinkage(VFTableLinkage) || + llvm::GlobalValue::isWeakODRLinkage(VFTableLinkage) || + llvm::GlobalValue::isLinkOnceODRLinkage(VFTableLinkage)) { + // The alias is going to be dropped into a Comdat, no need to make it + // weak. + if (!llvm::GlobalValue::isInternalLinkage(VFTableLinkage)) + VFTableLinkage = llvm::GlobalValue::ExternalLinkage; + llvm::Comdat *C = + CGM.getModule().getOrInsertComdat(VFTable->getName()); + // We must indicate which VFTable is larger to support linking between + // translation units which do and do not have RTTI data. The largest + // VFTable contains the RTTI data; translation units which reference + // the smaller VFTable always reference it relative to the first + // virtual method. + C->setSelectionKind(llvm::Comdat::Largest); + VTable->setComdat(C); + } else { + llvm_unreachable("unexpected linkage for vftable!"); + } + } + VFTable->setLinkage(VFTableLinkage); + CGM.setGlobalVisibility(VFTable, RD); + VFTablesMap[ID] = VFTable; + } + break; + } + + return VTable; +} + +llvm::Value *MicrosoftCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF, + GlobalDecl GD, + llvm::Value *This, + llvm::Type *Ty) { + GD = GD.getCanonicalDecl(); + CGBuilderTy &Builder = CGF.Builder; + + Ty = Ty->getPointerTo()->getPointerTo(); + llvm::Value *VPtr = + adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true); + llvm::Value *VTable = CGF.GetVTablePtr(VPtr, Ty); + + MicrosoftVTableContext::MethodVFTableLocation ML = + CGM.getMicrosoftVTableContext().getMethodVFTableLocation(GD); + llvm::Value *VFuncPtr = + Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn"); + return Builder.CreateLoad(VFuncPtr); +} + +llvm::Value *MicrosoftCXXABI::EmitVirtualDestructorCall( + CodeGenFunction &CGF, const CXXDestructorDecl *Dtor, CXXDtorType DtorType, + llvm::Value *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); + + ASTContext &Context = CGF.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, + 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); + Out.flush(); + + // 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); + + 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( + getThisValue(CGF), ThunkTy->getPointerTo()->getPointerTo()); + llvm::Value *VFuncPtr = + CGF.Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn"); + llvm::Value *Callee = CGF.Builder.CreateLoad(VFuncPtr); + + 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]; + 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); + Out.flush(); + 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); + + 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 = + CGM.getContext().getASTRecordLayout(VBT.BaseWithVPtr); + const ASTRecordLayout &DerivedLayout = + CGM.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); + + // Set the right visibility. + CGM.setGlobalVisibility(GV, RD); +} + +llvm::Value *MicrosoftCXXABI::performThisAdjustment(CodeGenFunction &CGF, + llvm::Value *This, + const ThisAdjustment &TA) { + if (TA.isEmpty()) + return This; + + llvm::Value *V = CGF.Builder.CreateBitCast(This, CGF.Int8PtrTy); + + if (!TA.Virtual.isEmpty()) { + assert(TA.Virtual.Microsoft.VtordispOffset < 0); + // Adjust the this argument based on the vtordisp value. + llvm::Value *VtorDispPtr = + CGF.Builder.CreateConstGEP1_32(V, TA.Virtual.Microsoft.VtordispOffset); + VtorDispPtr = + CGF.Builder.CreateBitCast(VtorDispPtr, CGF.Int32Ty->getPointerTo()); + llvm::Value *VtorDisp = CGF.Builder.CreateLoad(VtorDispPtr, "vtordisp"); + V = CGF.Builder.CreateGEP(V, CGF.Builder.CreateNeg(VtorDisp)); + + 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, V, -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, llvm::Value *Ret, + const ReturnAdjustment &RA) { + if (RA.isEmpty()) + return Ret; + + llvm::Value *V = CGF.Builder.CreateBitCast(Ret, CGF.Int8PtrTy); + + if (RA.Virtual.Microsoft.VBIndex) { + assert(RA.Virtual.Microsoft.VBIndex > 0); + int32_t IntSize = + getContext().getTypeSizeInChars(getContext().IntTy).getQuantity(); + llvm::Value *VBPtr; + llvm::Value *VBaseOffset = + GetVBaseOffsetFromVBPtr(CGF, V, RA.Virtual.Microsoft.VBPtrOffset, + IntSize * RA.Virtual.Microsoft.VBIndex, &VBPtr); + V = CGF.Builder.CreateInBoundsGEP(VBPtr, VBaseOffset); + } + + if (RA.NonVirtual) + V = CGF.Builder.CreateConstInBoundsGEP1_32(V, RA.NonVirtual); + + // Cast back to the original type. + return CGF.Builder.CreateBitCast(V, Ret->getType()); +} + +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, + llvm::Value *allocPtr, + CharUnits cookieSize) { + unsigned AS = allocPtr->getType()->getPointerAddressSpace(); + llvm::Value *numElementsPtr = + CGF.Builder.CreateBitCast(allocPtr, CGF.SizeTy->getPointerTo(AS)); + return CGF.Builder.CreateLoad(numElementsPtr); +} + +llvm::Value* MicrosoftCXXABI::InitializeArrayCookie(CodeGenFunction &CGF, + llvm::Value *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. + llvm::Value *cookiePtr = newPtr; + + // Write the number of elements into the appropriate slot. + unsigned AS = newPtr->getType()->getPointerAddressSpace(); + llvm::Value *numElementsPtr + = CGF.Builder.CreateBitCast(cookiePtr, CGF.SizeTy->getPointerTo(AS)); + CGF.Builder.CreateStore(numElements, numElementsPtr); + + // Finally, compute a pointer to the actual data buffer by skipping + // over the cookie completely. + return CGF.Builder.CreateConstInBoundsGEP1_64(newPtr, + cookieSize.getQuantity()); +} + +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<std::pair<const VarDecl *, llvm::GlobalVariable *>> + CXXThreadLocals, + ArrayRef<llvm::Function *> CXXThreadLocalInits, + ArrayRef<llvm::GlobalVariable *> 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 = CXXThreadLocalInitVars[I]; + llvm::Function *F = CXXThreadLocalInits[I]; + + // If the GV is already in a comdat group, then we have to join it. + llvm::Comdat *C = GV->getComdat(); + + // LinkOnce and Weak linkage are lowered down to a single-member comdat + // group. + // Make an explicit group so we can join it. + if (!C && (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage())) { + C = CGM.getModule().getOrInsertComdat(GV->getName()); + GV->setComdat(C); + 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", 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(); +} + +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. + CGF.CurFn->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage); + CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit); + return; + } + + // MSVC always uses an i32 bitfield to guard initialization, which is *not* + // threadsafe. Since the user may be linking in inline functions compiled by + // cl.exe, there's no reason to provide a false sense of security by using + // critical sections here. + + if (D.getTLSKind()) + CGM.ErrorUnsupported(&D, "dynamic TLS initialization"); + + CGBuilderTy &Builder = CGF.Builder; + llvm::IntegerType *GuardTy = CGF.Int32Ty; + llvm::ConstantInt *Zero = llvm::ConstantInt::get(GuardTy, 0); + + // Get the guard variable for this function if we have one already. + GuardInfo *GI = &GuardVariableMap[D.getDeclContext()]; + + unsigned BitIndex; + if (D.isStaticLocal() && D.isExternallyVisible()) { + // Externally visible variables have to be numbered in Sema to properly + // handle unreachable VarDecls. + BitIndex = getContext().getStaticLocalNumber(&D); + assert(BitIndex > 0); + BitIndex--; + } else { + // Non-externally visible variables are numbered here in CodeGen. + BitIndex = GI->BitIndex++; + } + + if (BitIndex >= 32) { + if (D.isExternallyVisible()) + ErrorUnsupportedABI(CGF, "more than 32 guarded initializations"); + BitIndex %= 32; + GI->Guard = nullptr; + } + + // Lazily create the i32 bitfield for this function. + if (!GI->Guard) { + // Mangle the name for the guard. + SmallString<256> GuardName; + { + llvm::raw_svector_ostream Out(GuardName); + getMangleContext().mangleStaticGuardVariable(&D, Out); + Out.flush(); + } + + // Create the guard variable with a zero-initializer. Just absorb linkage, + // visibility and dll storage class from the guarded variable. + GI->Guard = + new llvm::GlobalVariable(CGM.getModule(), GuardTy, false, + GV->getLinkage(), Zero, GuardName.str()); + GI->Guard->setVisibility(GV->getVisibility()); + GI->Guard->setDLLStorageClass(GV->getDLLStorageClass()); + } else { + assert(GI->Guard->getLinkage() == GV->getLinkage() && + "static local from the same function had different linkage"); + } + + // 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 << BitIndex); + llvm::LoadInst *LI = Builder.CreateLoad(GI->Guard); + 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), GI->Guard); + CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit); + Builder.CreateBr(EndBlock); + + // Continue. + 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) +{ + 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 (RD->getNumVBases()) + 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(getZeroInt()); + + return llvm::ConstantStruct::getAnon(fields); +} + +llvm::Constant * +MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT, + CharUnits offset) { + const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl(); + llvm::Constant *FirstField = + llvm::ConstantInt::get(CGM.IntTy, offset.getQuantity()); + return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/false, RD, + CharUnits::Zero()); +} + +llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const CXXMethodDecl *MD) { + return BuildMemberPointer(MD->getParent(), MD, CharUnits::Zero()); +} + +llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const APValue &MP, + QualType MPType) { + const MemberPointerType *MPT = MPType->castAs<MemberPointerType>(); + const ValueDecl *MPD = MP.getMemberPointerDecl(); + if (!MPD) + return EmitNullMemberPointer(MPT); + + CharUnits ThisAdjustment = getMemberPointerPathAdjustment(MP); + + // FIXME PR15713: Support virtual inheritance paths. + + if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MPD)) + return BuildMemberPointer(MPT->getMostRecentCXXRecordDecl(), MD, + ThisAdjustment); + + CharUnits FieldOffset = + getContext().toCharUnitsFromBits(getContext().getFieldOffset(MPD)); + return EmitMemberDataPointer(MPT, ThisAdjustment + FieldOffset); +} + +llvm::Constant * +MicrosoftCXXABI::BuildMemberPointer(const CXXRecordDecl *RD, + const CXXMethodDecl *MD, + CharUnits NonVirtualBaseAdjustment) { + assert(MD->isInstance() && "Member function must not be static!"); + MD = MD->getCanonicalDecl(); + RD = RD->getMostRecentDecl(); + CodeGenTypes &Types = CGM.getTypes(); + + 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); + FirstField = llvm::ConstantExpr::getBitCast(FirstField, CGM.VoidPtrTy); + } else { + MicrosoftVTableContext::MethodVFTableLocation ML = + CGM.getMicrosoftVTableContext().getMethodVFTableLocation(MD); + if (!CGM.getTypes().isFuncTypeConvertible( + MD->getType()->castAs<FunctionType>())) { + CGM.ErrorUnsupported(MD, "pointer to virtual member function with " + "incomplete return or parameter type"); + FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy); + } else if (FPT->getCallConv() == CC_X86FastCall) { + CGM.ErrorUnsupported(MD, "pointer to fastcall virtual member function"); + FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy); + } else if (ML.VBase) { + CGM.ErrorUnsupported(MD, "pointer to virtual member function overriding " + "member function in virtual base class"); + FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy); + } else { + llvm::Function *Thunk = EmitVirtualMemPtrThunk(MD, ML); + FirstField = llvm::ConstantExpr::getBitCast(Thunk, CGM.VoidPtrTy); + // Include the vfptr adjustment if the method is in a non-primary vftable. + NonVirtualBaseAdjustment += ML.VFPtrOffset; + } + } + + // The rest of the fields are common with data member pointers. + return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/true, RD, + NonVirtualBaseAdjustment); +} + +/// 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, + llvm::Value *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.CreateBitCast(This, CGM.Int8PtrTy); + llvm::Value *VBPtr = + Builder.CreateInBoundsGEP(This, VBPtrOffset, "vbptr"); + if (VBPtrOut) *VBPtrOut = VBPtr; + VBPtr = Builder.CreateBitCast(VBPtr, + CGM.Int32Ty->getPointerTo(0)->getPointerTo(0)); + llvm::Value *VBTable = Builder.CreateLoad(VBPtr, "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.CreateLoad(VBaseOffs, "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, + llvm::Value *Base, llvm::Value *VBTableOffset, llvm::Value *VBPtrOffset) { + CGBuilderTy &Builder = CGF.Builder; + Base = Builder.CreateBitCast(Base, CGM.Int8PtrTy); + 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, OriginalBB); + Phi->addIncoming(AdjustedBase, VBaseAdjustBB); + return Phi; + } + return AdjustedBase; +} + +llvm::Value *MicrosoftCXXABI::EmitMemberDataPointerAddress( + CodeGenFunction &CGF, const Expr *E, llvm::Value *Base, llvm::Value *MemPtr, + const MemberPointerType *MPT) { + assert(MPT->isMemberDataPointer()); + unsigned AS = Base->getType()->getPointerAddressSpace(); + 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++); + } + + if (VirtualBaseAdjustmentOffset) { + Base = AdjustVirtualBase(CGF, E, RD, Base, VirtualBaseAdjustmentOffset, + VBPtrOffset); + } + + // Cast to char*. + Base = Builder.CreateBitCast(Base, Builder.getInt8Ty()->getPointerTo(AS)); + + // Apply the offset, which we assume is non-null. + llvm::Value *Addr = + Builder.CreateInBoundsGEP(Base, FieldOffset, "memptr.offset"); + + // Cast the address to the appropriate pointer type, adopting the address + // space of the base pointer. + return Builder.CreateBitCast(Addr, PType); +} + +static MSInheritanceAttr::Spelling +getInheritanceFromMemptr(const MemberPointerType *MPT) { + return MPT->getMostRecentCXXRecordDecl()->getMSInheritanceModel(); +} + +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); + + // Decompose src. + llvm::Value *FirstField = Src; + llvm::Value *NonVirtualBaseAdjustment = nullptr; + llvm::Value *VirtualBaseAdjustmentOffset = nullptr; + llvm::Value *VBPtrOffset = nullptr; + MSInheritanceAttr::Spelling SrcInheritance = SrcRD->getMSInheritanceModel(); + 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++); + } + + // For data pointers, we adjust the field offset directly. For functions, we + // have a separate field. + llvm::Constant *Adj = getMemberPointerAdjustment(E); + if (Adj) { + Adj = llvm::ConstantExpr::getTruncOrBitCast(Adj, CGM.IntTy); + llvm::Value *&NVAdjustField = IsFunc ? NonVirtualBaseAdjustment : FirstField; + bool isDerivedToBase = (E->getCastKind() == CK_DerivedToBaseMemberPointer); + if (!NVAdjustField) // If this field didn't exist in src, it's zero. + NVAdjustField = getZeroInt(); + if (isDerivedToBase) + NVAdjustField = Builder.CreateNSWSub(NVAdjustField, Adj, "adj"); + else + NVAdjustField = Builder.CreateNSWAdd(NVAdjustField, Adj, "adj"); + } + + // FIXME PR15713: Support conversions through virtually derived classes. + + // Recompose dst from the null struct and the adjusted fields from src. + MSInheritanceAttr::Spelling DstInheritance = DstRD->getMSInheritanceModel(); + llvm::Value *Dst; + if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance)) { + Dst = FirstField; + } else { + Dst = llvm::UndefValue::get(DstNull->getType()); + unsigned Idx = 0; + Dst = Builder.CreateInsertValue(Dst, FirstField, Idx++); + if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance)) + Dst = Builder.CreateInsertValue( + Dst, getValueOrZeroInt(NonVirtualBaseAdjustment), Idx++); + if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance)) + Dst = Builder.CreateInsertValue( + Dst, getValueOrZeroInt(VBPtrOffset), Idx++); + if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance)) + Dst = Builder.CreateInsertValue( + Dst, getValueOrZeroInt(VirtualBaseAdjustmentOffset), Idx++); + } + 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::Constant * +MicrosoftCXXABI::EmitMemberPointerConversion(const CastExpr *E, + llvm::Constant *Src) { + const MemberPointerType *SrcTy = + E->getSubExpr()->getType()->castAs<MemberPointerType>(); + const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>(); + + // 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 (E->getCastKind() == CK_ReinterpretMemberPointer) + return Src; + + MSInheritanceAttr::Spelling SrcInheritance = getInheritanceFromMemptr(SrcTy); + MSInheritanceAttr::Spelling DstInheritance = getInheritanceFromMemptr(DstTy); + + // Decompose src. + llvm::Constant *FirstField = Src; + llvm::Constant *NonVirtualBaseAdjustment = nullptr; + llvm::Constant *VirtualBaseAdjustmentOffset = nullptr; + llvm::Constant *VBPtrOffset = nullptr; + bool IsFunc = SrcTy->isMemberFunctionPointer(); + if (!MSInheritanceAttr::hasOnlyOneField(IsFunc, SrcInheritance)) { + // We need to extract values. + unsigned I = 0; + FirstField = Src->getAggregateElement(I++); + if (MSInheritanceAttr::hasNVOffsetField(IsFunc, SrcInheritance)) + NonVirtualBaseAdjustment = Src->getAggregateElement(I++); + if (MSInheritanceAttr::hasVBPtrOffsetField(SrcInheritance)) + VBPtrOffset = Src->getAggregateElement(I++); + if (MSInheritanceAttr::hasVBTableOffsetField(SrcInheritance)) + VirtualBaseAdjustmentOffset = Src->getAggregateElement(I++); + } + + // For data pointers, we adjust the field offset directly. For functions, we + // have a separate field. + llvm::Constant *Adj = getMemberPointerAdjustment(E); + if (Adj) { + Adj = llvm::ConstantExpr::getTruncOrBitCast(Adj, CGM.IntTy); + llvm::Constant *&NVAdjustField = + IsFunc ? NonVirtualBaseAdjustment : FirstField; + bool IsDerivedToBase = (E->getCastKind() == CK_DerivedToBaseMemberPointer); + if (!NVAdjustField) // If this field didn't exist in src, it's zero. + NVAdjustField = getZeroInt(); + if (IsDerivedToBase) + NVAdjustField = llvm::ConstantExpr::getNSWSub(NVAdjustField, Adj); + else + NVAdjustField = llvm::ConstantExpr::getNSWAdd(NVAdjustField, Adj); + } + + // FIXME PR15713: Support conversions through virtually derived classes. + + // Recompose dst from the null struct and the adjusted fields from src. + if (MSInheritanceAttr::hasOnlyOneField(IsFunc, DstInheritance)) + return FirstField; + + llvm::SmallVector<llvm::Constant *, 4> Fields; + Fields.push_back(FirstField); + if (MSInheritanceAttr::hasNVOffsetField(IsFunc, DstInheritance)) + Fields.push_back(getConstantOrZeroInt(NonVirtualBaseAdjustment)); + if (MSInheritanceAttr::hasVBPtrOffsetField(DstInheritance)) + Fields.push_back(getConstantOrZeroInt(VBPtrOffset)); + if (MSInheritanceAttr::hasVBTableOffsetField(DstInheritance)) + Fields.push_back(getConstantOrZeroInt(VirtualBaseAdjustmentOffset)); + return llvm::ConstantStruct::getAnon(Fields); +} + +llvm::Value *MicrosoftCXXABI::EmitLoadOfMemberFunctionPointer( + CodeGenFunction &CGF, const Expr *E, llvm::Value *&This, + 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)); + 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) { + This = AdjustVirtualBase(CGF, E, RD, This, VirtualBaseAdjustmentOffset, + VBPtrOffset); + } + + if (NonVirtualBaseAdjustment) { + // Apply the adjustment and cast back to the original struct type. + llvm::Value *Ptr = Builder.CreateBitCast(This, Builder.getInt8PtrTy()); + Ptr = Builder.CreateInBoundsGEP(Ptr, NonVirtualBaseAdjustment); + This = Builder.CreateBitCast(Ptr, This->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.c_str()); + + // 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( + getBaseClassArray(Classes), + 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.c_str()); + + // 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.c_str()); + + // 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.c_str()); + + // 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)); + return COL; +} + +/// \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, TypeInfoString; + { + 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. + { + 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); + return llvm::ConstantExpr::getBitCast( + new llvm::GlobalVariable( + CGM.getModule(), TypeDescriptorType, /*Constant=*/false, + getLinkageForRTTI(Type), + llvm::ConstantStruct::get(TypeDescriptorType, Fields), + MangledName.c_str()), + 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. + CGM.codegenCXXStructor(ctor, StructorType::Complete); +} + +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; + + CGM.codegenCXXStructor(dtor, dtorType); +} + +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); +} |
