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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 | 1941 |
1 files changed, 1941 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..7318fe7 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/CodeGen/MicrosoftCXXABI.cpp @@ -0,0 +1,1941 @@ +//===--- 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 "CodeGenModule.h" +#include "CGVTables.h" +#include "MicrosoftVBTables.h" +#include "clang/AST/Decl.h" +#include "clang/AST/DeclCXX.h" +#include "clang/AST/VTableBuilder.h" +#include "llvm/ADT/StringSet.h" + +using namespace clang; +using namespace CodeGen; + +namespace { + +class MicrosoftCXXABI : public CGCXXABI { +public: + MicrosoftCXXABI(CodeGenModule &CGM) : CGCXXABI(CGM) {} + + bool HasThisReturn(GlobalDecl GD) const; + + bool isReturnTypeIndirect(const CXXRecordDecl *RD) const { + // Structures that are not C++03 PODs are always indirect. + return !RD->isPOD(); + } + + RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const { + if (RD->hasNonTrivialCopyConstructor() || RD->hasNonTrivialDestructor()) + return RAA_DirectInMemory; + return RAA_Default; + } + + StringRef GetPureVirtualCallName() { return "_purecall"; } + // No known support for deleted functions in MSVC yet, so this choice is + // arbitrary. + StringRef GetDeletedVirtualCallName() { return "_purecall"; } + + bool isInlineInitializedStaticDataMemberLinkOnce() { return true; } + + llvm::Value *adjustToCompleteObject(CodeGenFunction &CGF, + llvm::Value *ptr, + QualType type); + + llvm::Value *GetVirtualBaseClassOffset(CodeGenFunction &CGF, + llvm::Value *This, + const CXXRecordDecl *ClassDecl, + const CXXRecordDecl *BaseClassDecl); + + void BuildConstructorSignature(const CXXConstructorDecl *Ctor, + CXXCtorType Type, + CanQualType &ResTy, + SmallVectorImpl<CanQualType> &ArgTys); + + llvm::BasicBlock *EmitCtorCompleteObjectHandler(CodeGenFunction &CGF, + const CXXRecordDecl *RD); + + void initializeHiddenVirtualInheritanceMembers(CodeGenFunction &CGF, + const CXXRecordDecl *RD); + + void EmitCXXConstructors(const CXXConstructorDecl *D); + + // 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 BuildDestructorSignature(const CXXDestructorDecl *Dtor, + CXXDtorType Type, + CanQualType &ResTy, + SmallVectorImpl<CanQualType> &ArgTys); + + /// Non-base dtors should be emitted as delegating thunks in this ABI. + bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor, + CXXDtorType DT) const { + return DT != Dtor_Base; + } + + void EmitCXXDestructors(const CXXDestructorDecl *D); + + const CXXRecordDecl *getThisArgumentTypeForMethod(const CXXMethodDecl *MD) { + 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 0; + } + return MD->getParent(); + } + + llvm::Value *adjustThisArgumentForVirtualCall(CodeGenFunction &CGF, + GlobalDecl GD, + llvm::Value *This); + + void BuildInstanceFunctionParams(CodeGenFunction &CGF, + QualType &ResTy, + FunctionArgList &Params); + + llvm::Value *adjustThisParameterInVirtualFunctionPrologue( + CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This); + + void EmitInstanceFunctionProlog(CodeGenFunction &CGF); + + void EmitConstructorCall(CodeGenFunction &CGF, + const CXXConstructorDecl *D, CXXCtorType Type, + bool ForVirtualBase, bool Delegating, + llvm::Value *This, + CallExpr::const_arg_iterator ArgBeg, + CallExpr::const_arg_iterator ArgEnd); + + void emitVTableDefinitions(CodeGenVTables &CGVT, const CXXRecordDecl *RD); + + llvm::Value *getVTableAddressPointInStructor( + CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, + BaseSubobject Base, const CXXRecordDecl *NearestVBase, + bool &NeedsVirtualOffset); + + llvm::Constant * + getVTableAddressPointForConstExpr(BaseSubobject Base, + const CXXRecordDecl *VTableClass); + + llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD, + CharUnits VPtrOffset); + + llvm::Value *getVirtualFunctionPointer(CodeGenFunction &CGF, GlobalDecl GD, + llvm::Value *This, llvm::Type *Ty); + + void EmitVirtualDestructorCall(CodeGenFunction &CGF, + const CXXDestructorDecl *Dtor, + CXXDtorType DtorType, SourceLocation CallLoc, + llvm::Value *This); + + void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF, GlobalDecl GD, + CallArgList &CallArgs) { + 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); + + void setThunkLinkage(llvm::Function *Thunk, bool ForVTable) { + Thunk->setLinkage(llvm::GlobalValue::WeakAnyLinkage); + } + + llvm::Value *performThisAdjustment(CodeGenFunction &CGF, llvm::Value *This, + const ThisAdjustment &TA); + + llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret, + const ReturnAdjustment &RA); + + void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D, + llvm::GlobalVariable *DeclPtr, + bool PerformInit); + + // ==== 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); + bool requiresArrayCookie(const CXXNewExpr *expr); + CharUnits getArrayCookieSizeImpl(QualType type); + llvm::Value *InitializeArrayCookie(CodeGenFunction &CGF, + llvm::Value *NewPtr, + llvm::Value *NumElements, + const CXXNewExpr *expr, + QualType ElementType); + llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF, + llvm::Value *allocPtr, + CharUnits cookieSize); + +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(); + } + + void + GetNullMemberPointerFields(const MemberPointerType *MPT, + llvm::SmallVectorImpl<llvm::Constant *> &fields); + + /// \brief Finds the offset from the base of RD to the vbptr it uses, even if + /// it is reusing a vbptr from a non-virtual base. RD must have morally + /// virtual bases. + CharUnits GetVBPtrOffsetFromBases(const CXXRecordDecl *RD); + + /// \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 = 0); + + llvm::Value *GetVBaseOffsetFromVBPtr(CodeGenFunction &CGF, + llvm::Value *Base, + int32_t VBPtrOffset, + int32_t VBTableOffset, + llvm::Value **VBPtr = 0) { + 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 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 VBTableVector &EnumerateVBTables(const CXXRecordDecl *RD); + + /// \brief Generate a thunk for calling a virtual member function MD. + llvm::Function *EmitVirtualMemPtrThunk(const CXXMethodDecl *MD, + StringRef ThunkName); + +public: + virtual llvm::Type *ConvertMemberPointerType(const MemberPointerType *MPT); + + virtual bool isZeroInitializable(const MemberPointerType *MPT); + + virtual llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT); + + virtual llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT, + CharUnits offset); + virtual llvm::Constant *EmitMemberPointer(const CXXMethodDecl *MD); + virtual llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT); + + virtual llvm::Value *EmitMemberPointerComparison(CodeGenFunction &CGF, + llvm::Value *L, + llvm::Value *R, + const MemberPointerType *MPT, + bool Inequality); + + virtual llvm::Value *EmitMemberPointerIsNotNull(CodeGenFunction &CGF, + llvm::Value *MemPtr, + const MemberPointerType *MPT); + + virtual llvm::Value *EmitMemberDataPointerAddress(CodeGenFunction &CGF, + llvm::Value *Base, + llvm::Value *MemPtr, + const MemberPointerType *MPT); + + virtual llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF, + const CastExpr *E, + llvm::Value *Src); + + virtual llvm::Constant *EmitMemberPointerConversion(const CastExpr *E, + llvm::Constant *Src); + + virtual llvm::Value * + EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, + llvm::Value *&This, + llvm::Value *MemPtr, + const MemberPointerType *MPT); + +private: + typedef std::pair<const CXXRecordDecl *, CharUnits> VFTableIdTy; + typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalVariable *> VFTablesMapTy; + /// \brief All the vftables that have been referenced. + VFTablesMapTy VFTablesMap; + + /// \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 *, VBTableVector> 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(0), 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::Value *MicrosoftCXXABI::adjustToCompleteObject(CodeGenFunction &CGF, + llvm::Value *ptr, + QualType type) { + // FIXME: implement + return ptr; +} + +/// \brief Finds the first non-virtual base of RD that has virtual bases. If RD +/// doesn't have a vbptr, it will reuse the vbptr of the returned class. +static const CXXRecordDecl *FindFirstNVBaseWithVBases(const CXXRecordDecl *RD) { + for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(), + E = RD->bases_end(); I != E; ++I) { + const CXXRecordDecl *Base = I->getType()->getAsCXXRecordDecl(); + if (!I->isVirtual() && Base->getNumVBases() > 0) + return Base; + } + llvm_unreachable("RD must have an nv base with vbases"); +} + +CharUnits MicrosoftCXXABI::GetVBPtrOffsetFromBases(const CXXRecordDecl *RD) { + assert(RD->getNumVBases()); + CharUnits Total = CharUnits::Zero(); + while (RD) { + const ASTRecordLayout &RDLayout = getContext().getASTRecordLayout(RD); + CharUnits VBPtrOffset = RDLayout.getVBPtrOffset(); + // -1 is the sentinel for no vbptr. + if (VBPtrOffset != CharUnits::fromQuantity(-1)) { + Total += VBPtrOffset; + break; + } + RD = FindFirstNVBaseWithVBases(RD); + Total += RDLayout.getBaseClassOffset(RD); + } + return Total; +} + +llvm::Value * +MicrosoftCXXABI::GetVirtualBaseClassOffset(CodeGenFunction &CGF, + llvm::Value *This, + const CXXRecordDecl *ClassDecl, + const CXXRecordDecl *BaseClassDecl) { + int64_t VBPtrChars = GetVBPtrOffsetFromBases(ClassDecl).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()); +} + +void MicrosoftCXXABI::BuildConstructorSignature(const CXXConstructorDecl *Ctor, + CXXCtorType Type, + CanQualType &ResTy, + SmallVectorImpl<CanQualType> &ArgTys) { + // 'this' parameter and 'this' return are already in place + + const CXXRecordDecl *Class = Ctor->getParent(); + if (Class->getNumVBases()) { + // Constructors of classes with virtual bases take an implicit parameter. + ArgTys.push_back(CGM.getContext().IntTy); + } +} + +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 = 0; // 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 VBTableVector &VBTables = EnumerateVBTables(RD); + for (VBTableVector::const_iterator I = VBTables.begin(), E = VBTables.end(); + I != E; ++I) { + const ASTRecordLayout &SubobjectLayout = + CGM.getContext().getASTRecordLayout(I->VBPtrSubobject.getBase()); + uint64_t Offs = (I->VBPtrSubobject.getBaseOffset() + + SubobjectLayout.getVBPtrOffset()).getQuantity(); + llvm::Value *VBPtr = + CGF.Builder.CreateConstInBoundsGEP1_64(ThisInt8Ptr, Offs); + VBPtr = CGF.Builder.CreateBitCast(VBPtr, I->GV->getType()->getPointerTo(0), + "vbptr." + I->ReusingBase->getName()); + CGF.Builder.CreateStore(I->GV, VBPtr); + } +} + +void MicrosoftCXXABI::BuildDestructorSignature(const CXXDestructorDecl *Dtor, + CXXDtorType Type, + CanQualType &ResTy, + SmallVectorImpl<CanQualType> &ArgTys) { + // 'this' is already in place + + // TODO: 'for base' flag + + if (Type == Dtor_Deleting) { + // The scalar deleting destructor takes an implicit int parameter. + 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)); +} + +llvm::Value *MicrosoftCXXABI::adjustThisArgumentForVirtualCall( + CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) { + GD = GD.getCanonicalDecl(); + const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl()); + // FIXME: consider splitting the vdtor vs regular method code into two + // functions. + + 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; + if (ML.VBase) { + bool AvoidVirtualOffset = false; + if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base) { + // A base destructor can only be called from a complete destructor of the + // same record type or another destructor of a more derived type; + // or a constructor of the same record type if an exception is thrown. + assert(isa<CXXDestructorDecl>(CGF.CurGD.getDecl()) || + isa<CXXConstructorDecl>(CGF.CurGD.getDecl())); + const CXXRecordDecl *CurRD = + cast<CXXMethodDecl>(CGF.CurGD.getDecl())->getParent(); + + if (MD->getParent() == CurRD) { + if (isa<CXXDestructorDecl>(CGF.CurGD.getDecl())) + assert(CGF.CurGD.getDtorType() == Dtor_Complete); + if (isa<CXXConstructorDecl>(CGF.CurGD.getDecl())) + assert(CGF.CurGD.getCtorType() == Ctor_Complete); + // We're calling the main base dtor from a complete structor, + // so we know the "this" offset statically. + AvoidVirtualOffset = true; + } else { + // Let's see if we try to call a destructor of a non-virtual base. + for (CXXRecordDecl::base_class_const_iterator I = CurRD->bases_begin(), + E = CurRD->bases_end(); I != E; ++I) { + if (I->getType()->getAsCXXRecordDecl() != MD->getParent()) + continue; + // If we call a base destructor for a non-virtual base, we statically + // know where it expects the vfptr and "this" to be. + // The total offset should reflect the adjustment done by + // adjustThisParameterInVirtualFunctionPrologue(). + AvoidVirtualOffset = true; + break; + } + } + } + + if (AvoidVirtualOffset) { + const ASTRecordLayout &Layout = + CGF.getContext().getASTRecordLayout(MD->getParent()); + StaticOffset += Layout.getVBaseClassOffset(ML.VBase); + } else { + 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; +} + +static bool IsDeletingDtor(GlobalDecl GD) { + const CXXMethodDecl* MD = cast<CXXMethodDecl>(GD.getDecl()); + if (isa<CXXDestructorDecl>(MD)) { + return GD.getDtorType() == Dtor_Deleting; + } + return false; +} + +void MicrosoftCXXABI::BuildInstanceFunctionParams(CodeGenFunction &CGF, + QualType &ResTy, + FunctionArgList &Params) { + BuildThisParam(CGF, Params); + + ASTContext &Context = getContext(); + const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl()); + if (isa<CXXConstructorDecl>(MD) && MD->getParent()->getNumVBases()) { + ImplicitParamDecl *IsMostDerived + = ImplicitParamDecl::Create(Context, 0, + CGF.CurGD.getDecl()->getLocation(), + &Context.Idents.get("is_most_derived"), + Context.IntTy); + Params.push_back(IsMostDerived); + getStructorImplicitParamDecl(CGF) = IsMostDerived; + } else if (IsDeletingDtor(CGF.CurGD)) { + ImplicitParamDecl *ShouldDelete + = ImplicitParamDecl::Create(Context, 0, + 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) { + 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 This; + + // 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); + } + + // 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 ther 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. + + MicrosoftVTableContext::MethodVFTableLocation ML = + CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD); + CharUnits Adjustment = ML.VFPtrOffset; + if (ML.VBase) { + const ASTRecordLayout &DerivedLayout = + CGF.getContext().getASTRecordLayout(MD->getParent()); + Adjustment += DerivedLayout.getVBaseClassOffset(ML.VBase); + } + + 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); + + 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"); + } +} + +void MicrosoftCXXABI::EmitConstructorCall(CodeGenFunction &CGF, + const CXXConstructorDecl *D, + CXXCtorType Type, + bool ForVirtualBase, + bool Delegating, + llvm::Value *This, + CallExpr::const_arg_iterator ArgBeg, + CallExpr::const_arg_iterator ArgEnd) { + assert(Type == Ctor_Complete || Type == Ctor_Base); + llvm::Value *Callee = CGM.GetAddrOfCXXConstructor(D, Ctor_Complete); + + llvm::Value *ImplicitParam = 0; + QualType ImplicitParamTy; + if (D->getParent()->getNumVBases()) { + ImplicitParam = llvm::ConstantInt::get(CGM.Int32Ty, Type == Ctor_Complete); + ImplicitParamTy = getContext().IntTy; + } + + // FIXME: Provide a source location here. + CGF.EmitCXXMemberCall(D, SourceLocation(), Callee, ReturnValueSlot(), This, + ImplicitParam, ImplicitParamTy, ArgBeg, ArgEnd); +} + +void MicrosoftCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT, + const CXXRecordDecl *RD) { + MicrosoftVTableContext &VFTContext = CGM.getMicrosoftVTableContext(); + MicrosoftVTableContext::VFPtrListTy VFPtrs = VFTContext.getVFPtrOffsets(RD); + llvm::GlobalVariable::LinkageTypes Linkage = CGM.getVTableLinkage(RD); + + for (MicrosoftVTableContext::VFPtrListTy::iterator I = VFPtrs.begin(), + E = VFPtrs.end(); I != E; ++I) { + llvm::GlobalVariable *VTable = getAddrOfVTable(RD, I->VFPtrFullOffset); + if (VTable->hasInitializer()) + continue; + + const VTableLayout &VTLayout = + VFTContext.getVFTableLayout(RD, I->VFPtrFullOffset); + llvm::Constant *Init = CGVT.CreateVTableInitializer( + RD, VTLayout.vtable_component_begin(), + VTLayout.getNumVTableComponents(), VTLayout.vtable_thunk_begin(), + VTLayout.getNumVTableThunks()); + VTable->setInitializer(Init); + + VTable->setLinkage(Linkage); + CGM.setTypeVisibility(VTable, RD, CodeGenModule::TVK_ForVTable); + } +} + +llvm::Value *MicrosoftCXXABI::getVTableAddressPointInStructor( + CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, BaseSubobject Base, + const CXXRecordDecl *NearestVBase, bool &NeedsVirtualOffset) { + NeedsVirtualOffset = (NearestVBase != 0); + + llvm::Value *VTableAddressPoint = + getAddrOfVTable(VTableClass, Base.getBaseOffset()); + if (!VTableAddressPoint) { + assert(Base.getBase()->getNumVBases() && + !CGM.getContext().getASTRecordLayout(Base.getBase()).hasOwnVFPtr()); + } + return VTableAddressPoint; +} + +static void mangleVFTableName(MicrosoftMangleContext &MangleContext, + const CXXRecordDecl *RD, const VFPtrInfo &VFPtr, + SmallString<256> &Name) { + llvm::raw_svector_ostream Out(Name); + MangleContext.mangleCXXVFTable(RD, VFPtr.PathToMangle, Out); +} + +llvm::Constant *MicrosoftCXXABI::getVTableAddressPointForConstExpr( + BaseSubobject Base, const CXXRecordDecl *VTableClass) { + llvm::Constant *VTable = getAddrOfVTable(VTableClass, Base.getBaseOffset()); + assert(VTable && "Couldn't find a vftable for the given base?"); + return VTable; +} + +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); + VFTablesMapTy::iterator I; + bool Inserted; + llvm::tie(I, Inserted) = VFTablesMap.insert( + std::make_pair(ID, static_cast<llvm::GlobalVariable *>(0))); + if (!Inserted) + return I->second; + + llvm::GlobalVariable *&VTable = I->second; + + MicrosoftVTableContext &VTContext = CGM.getMicrosoftVTableContext(); + const MicrosoftVTableContext::VFPtrListTy &VFPtrs = + VTContext.getVFPtrOffsets(RD); + + if (DeferredVFTables.insert(RD)) { + // 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())) + llvm_unreachable("Already saw this mangling before?"); + } +#endif + } + + for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) { + if (VFPtrs[J].VFPtrFullOffset != VPtrOffset) + continue; + + llvm::ArrayType *ArrayType = llvm::ArrayType::get( + CGM.Int8PtrTy, + VTContext.getVFTableLayout(RD, VFPtrs[J].VFPtrFullOffset) + .getNumVTableComponents()); + + SmallString<256> Name; + mangleVFTableName(getMangleContext(), RD, VFPtrs[J], Name); + VTable = CGM.CreateOrReplaceCXXRuntimeVariable( + Name.str(), ArrayType, llvm::GlobalValue::ExternalLinkage); + VTable->setUnnamedAddr(true); + 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 = adjustThisArgumentForVirtualCall(CGF, GD, This); + 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); +} + +void MicrosoftCXXABI::EmitVirtualDestructorCall(CodeGenFunction &CGF, + const CXXDestructorDecl *Dtor, + CXXDtorType DtorType, + SourceLocation CallLoc, + llvm::Value *This) { + 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().arrangeCXXDestructor(Dtor, Dtor_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 = adjustThisArgumentForVirtualCall(CGF, GD, This); + CGF.EmitCXXMemberCall(Dtor, CallLoc, Callee, ReturnValueSlot(), This, + ImplicitParam, Context.IntTy, 0, 0); +} + +const VBTableVector & +MicrosoftCXXABI::EnumerateVBTables(const CXXRecordDecl *RD) { + // At this layer, we can key the cache off of a single class, which is much + // easier than caching at the GlobalVariable layer. + llvm::DenseMap<const CXXRecordDecl*, VBTableVector>::iterator I; + bool added; + llvm::tie(I, added) = VBTablesMap.insert(std::make_pair(RD, VBTableVector())); + VBTableVector &VBTables = I->second; + if (!added) + return VBTables; + + VBTableBuilder(CGM, RD).enumerateVBTables(VBTables); + + return VBTables; +} + +llvm::Function * +MicrosoftCXXABI::EmitVirtualMemPtrThunk(const CXXMethodDecl *MD, + StringRef ThunkName) { + // 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().arrangeGlobalDeclaration(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); + + // Start codegen. + CodeGenFunction CGF(CGM); + CGF.StartThunk(ThunkFn, MD, FnInfo); + + // Get to the Callee. + llvm::Value *This = CGF.LoadCXXThis(); + llvm::Value *Callee = getVirtualFunctionPointer(CGF, MD, This, ThunkTy); + + // Make the call and return the result. + CGF.EmitCallAndReturnForThunk(MD, Callee, 0); + + return ThunkFn; +} + +void MicrosoftCXXABI::emitVirtualInheritanceTables(const CXXRecordDecl *RD) { + const VBTableVector &VBTables = EnumerateVBTables(RD); + llvm::GlobalVariable::LinkageTypes Linkage = CGM.getVTableLinkage(RD); + + for (VBTableVector::const_iterator I = VBTables.begin(), E = VBTables.end(); + I != E; ++I) { + I->EmitVBTableDefinition(CGM, RD, Linkage); + } +} + +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()); +} + +void MicrosoftCXXABI::EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D, + llvm::GlobalVariable *GV, + bool PerformInit) { + // 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.isExternallyVisible()) { + // Externally visible variables have to be numbered in Sema to properly + // handle unreachable VarDecls. + BitIndex = getContext().getManglingNumber(&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 = 0; + } + + // 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 + // and visibility from the guarded variable. + GI.Guard = new llvm::GlobalVariable(CGM.getModule(), GuardTy, false, + GV->getLinkage(), Zero, GuardName.str()); + GI.Guard->setVisibility(GV->getVisibility()); + } 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); +} + +// Member pointer helpers. +static bool hasVBPtrOffsetField(MSInheritanceModel Inheritance) { + return Inheritance == MSIM_Unspecified; +} + +static bool hasOnlyOneField(bool IsMemberFunction, + MSInheritanceModel Inheritance) { + return Inheritance <= MSIM_SinglePolymorphic || + (!IsMemberFunction && Inheritance <= MSIM_MultiplePolymorphic); +} + +// Only member pointers to functions need a this adjustment, since it can be +// combined with the field offset for data pointers. +static bool hasNonVirtualBaseAdjustmentField(bool IsMemberFunction, + MSInheritanceModel Inheritance) { + return (IsMemberFunction && Inheritance >= MSIM_Multiple); +} + +static bool hasVirtualBaseAdjustmentField(MSInheritanceModel Inheritance) { + return Inheritance >= MSIM_Virtual; +} + +// Use zero for the field offset of a null data member pointer if we can +// guarantee that zero is not a valid field offset, or if the member pointer has +// multiple fields. Polymorphic classes have a vfptr at offset zero, so we can +// use zero for null. If there are multiple fields, we can use zero even if it +// is a valid field offset because null-ness testing will check the other +// fields. +static bool nullFieldOffsetIsZero(MSInheritanceModel Inheritance) { + return Inheritance != MSIM_Multiple && Inheritance != MSIM_Single; +} + +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->getClass()->getAsCXXRecordDecl(); + MSInheritanceModel Inheritance = RD->getMSInheritanceModel(); + return (!hasVirtualBaseAdjustmentField(Inheritance) && + nullFieldOffsetIsZero(Inheritance)); +} + +llvm::Type * +MicrosoftCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) { + const CXXRecordDecl *RD = MPT->getClass()->getAsCXXRecordDecl(); + MSInheritanceModel 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 (hasNonVirtualBaseAdjustmentField(MPT->isMemberFunctionPointer(), + Inheritance)) + fields.push_back(CGM.IntTy); + if (hasVBPtrOffsetField(Inheritance)) + fields.push_back(CGM.IntTy); + if (hasVirtualBaseAdjustmentField(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->getClass()->getAsCXXRecordDecl(); + MSInheritanceModel Inheritance = RD->getMSInheritanceModel(); + if (MPT->isMemberFunctionPointer()) { + // FunctionPointerOrVirtualThunk + fields.push_back(llvm::Constant::getNullValue(CGM.VoidPtrTy)); + } else { + if (nullFieldOffsetIsZero(Inheritance)) + fields.push_back(getZeroInt()); // FieldOffset + else + fields.push_back(getAllOnesInt()); // FieldOffset + } + + if (hasNonVirtualBaseAdjustmentField(MPT->isMemberFunctionPointer(), + Inheritance)) + fields.push_back(getZeroInt()); + if (hasVBPtrOffsetField(Inheritance)) + fields.push_back(getZeroInt()); + if (hasVirtualBaseAdjustmentField(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) +{ + MSInheritanceModel Inheritance = RD->getMSInheritanceModel(); + + // Single inheritance class member pointer are represented as scalars instead + // of aggregates. + if (hasOnlyOneField(IsMemberFunction, Inheritance)) + return FirstField; + + llvm::SmallVector<llvm::Constant *, 4> fields; + fields.push_back(FirstField); + + if (hasNonVirtualBaseAdjustmentField(IsMemberFunction, Inheritance)) + fields.push_back(llvm::ConstantInt::get( + CGM.IntTy, NonVirtualBaseAdjustment.getQuantity())); + + if (hasVBPtrOffsetField(Inheritance)) { + CharUnits Offs = CharUnits::Zero(); + if (RD->getNumVBases()) + Offs = GetVBPtrOffsetFromBases(RD); + 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 (hasVirtualBaseAdjustmentField(Inheritance)) + fields.push_back(getZeroInt()); + + return llvm::ConstantStruct::getAnon(fields); +} + +llvm::Constant * +MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT, + CharUnits offset) { + const CXXRecordDecl *RD = MPT->getClass()->getAsCXXRecordDecl(); + 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->getClass()->getAsCXXRecordDecl(), + 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(); + CodeGenTypes &Types = CGM.getTypes(); + + llvm::Constant *FirstField; + if (!MD->isVirtual()) { + const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>(); + 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 (MD->isVariadic()) { + CGM.ErrorUnsupported(MD, "pointer to variadic virtual member function"); + FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy); + } else 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 (ML.VBase) { + CGM.ErrorUnsupported(MD, "pointer to virtual member function overriding " + "member function in virtual base class"); + FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy); + } else { + SmallString<256> ThunkName; + CharUnits PointerWidth = getContext().toCharUnitsFromBits( + getContext().getTargetInfo().getPointerWidth(0)); + uint64_t OffsetInVFTable = ML.Index * PointerWidth.getQuantity(); + llvm::raw_svector_ostream Out(ThunkName); + getMangleContext().mangleVirtualMemPtrThunk(MD, OffsetInVFTable, Out); + Out.flush(); + + llvm::Function *Thunk = EmitVirtualMemPtrThunk(MD, ThunkName.str()); + FirstField = llvm::ConstantExpr::getBitCast(Thunk, CGM.VoidPtrTy); + } + } + + // 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->getClass()->getAsCXXRecordDecl(); + MSInheritanceModel Inheritance = RD->getMSInheritanceModel(); + if (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 = 0; + 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.CreateAnd(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.Int8PtrTy->getPointerTo(0)); + llvm::Value *VBTable = Builder.CreateLoad(VBPtr, "vbtable"); + + // Load an i32 offset from the vb-table. + llvm::Value *VBaseOffs = Builder.CreateInBoundsGEP(VBTable, VBTableOffset); + 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 CXXRecordDecl *RD, llvm::Value *Base, + llvm::Value *VBTableOffset, + llvm::Value *VBPtrOffset) { + CGBuilderTy &Builder = CGF.Builder; + Base = Builder.CreateBitCast(Base, CGM.Int8PtrTy); + llvm::BasicBlock *OriginalBB = 0; + llvm::BasicBlock *SkipAdjustBB = 0; + llvm::BasicBlock *VBaseAdjustBB = 0; + + // 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->getNumVBases()) { + offs = GetVBPtrOffsetFromBases(RD); + } + VBPtrOffset = llvm::ConstantInt::get(CGM.IntTy, offs.getQuantity()); + } + llvm::Value *VBPtr = 0; + 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, + 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->getClass()->getAsCXXRecordDecl(); + MSInheritanceModel 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 = 0; + llvm::Value *VBPtrOffset = 0; + if (MemPtr->getType()->isStructTy()) { + // We need to extract values. + unsigned I = 0; + FieldOffset = Builder.CreateExtractValue(MemPtr, I++); + if (hasVBPtrOffsetField(Inheritance)) + VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++); + if (hasVirtualBaseAdjustmentField(Inheritance)) + VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++); + } + + if (VirtualBaseAdjustmentOffset) { + Base = AdjustVirtualBase(CGF, RD, Base, VirtualBaseAdjustmentOffset, + VBPtrOffset); + } + 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 MSInheritanceModel +getInheritanceFromMemptr(const MemberPointerType *MPT) { + return MPT->getClass()->getAsCXXRecordDecl()->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>(); + MSInheritanceModel SrcInheritance = getInheritanceFromMemptr(SrcTy); + MSInheritanceModel DstInheritance = getInheritanceFromMemptr(DstTy); + 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 || + nullFieldOffsetIsZero(SrcInheritance) == + nullFieldOffsetIsZero(DstInheritance))) + 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 = 0; + llvm::Value *VirtualBaseAdjustmentOffset = 0; + llvm::Value *VBPtrOffset = 0; + if (!hasOnlyOneField(IsFunc, SrcInheritance)) { + // We need to extract values. + unsigned I = 0; + FirstField = Builder.CreateExtractValue(Src, I++); + if (hasNonVirtualBaseAdjustmentField(IsFunc, SrcInheritance)) + NonVirtualBaseAdjustment = Builder.CreateExtractValue(Src, I++); + if (hasVBPtrOffsetField(SrcInheritance)) + VBPtrOffset = Builder.CreateExtractValue(Src, I++); + if (hasVirtualBaseAdjustmentField(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. + llvm::Value *Dst; + if (hasOnlyOneField(IsFunc, DstInheritance)) { + Dst = FirstField; + } else { + Dst = llvm::UndefValue::get(DstNull->getType()); + unsigned Idx = 0; + Dst = Builder.CreateInsertValue(Dst, FirstField, Idx++); + if (hasNonVirtualBaseAdjustmentField(IsFunc, DstInheritance)) + Dst = Builder.CreateInsertValue( + Dst, getValueOrZeroInt(NonVirtualBaseAdjustment), Idx++); + if (hasVBPtrOffsetField(DstInheritance)) + Dst = Builder.CreateInsertValue( + Dst, getValueOrZeroInt(VBPtrOffset), Idx++); + if (hasVirtualBaseAdjustmentField(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; + + MSInheritanceModel SrcInheritance = getInheritanceFromMemptr(SrcTy); + MSInheritanceModel DstInheritance = getInheritanceFromMemptr(DstTy); + + // Decompose src. + llvm::Constant *FirstField = Src; + llvm::Constant *NonVirtualBaseAdjustment = 0; + llvm::Constant *VirtualBaseAdjustmentOffset = 0; + llvm::Constant *VBPtrOffset = 0; + bool IsFunc = SrcTy->isMemberFunctionPointer(); + if (!hasOnlyOneField(IsFunc, SrcInheritance)) { + // We need to extract values. + unsigned I = 0; + FirstField = Src->getAggregateElement(I++); + if (hasNonVirtualBaseAdjustmentField(IsFunc, SrcInheritance)) + NonVirtualBaseAdjustment = Src->getAggregateElement(I++); + if (hasVBPtrOffsetField(SrcInheritance)) + VBPtrOffset = Src->getAggregateElement(I++); + if (hasVirtualBaseAdjustmentField(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 (hasOnlyOneField(IsFunc, DstInheritance)) + return FirstField; + + llvm::SmallVector<llvm::Constant *, 4> Fields; + Fields.push_back(FirstField); + if (hasNonVirtualBaseAdjustmentField(IsFunc, DstInheritance)) + Fields.push_back(getConstantOrZeroInt(NonVirtualBaseAdjustment)); + if (hasVBPtrOffsetField(DstInheritance)) + Fields.push_back(getConstantOrZeroInt(VBPtrOffset)); + if (hasVirtualBaseAdjustmentField(DstInheritance)) + Fields.push_back(getConstantOrZeroInt(VirtualBaseAdjustmentOffset)); + return llvm::ConstantStruct::getAnon(Fields); +} + +llvm::Value * +MicrosoftCXXABI::EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, + llvm::Value *&This, + llvm::Value *MemPtr, + const MemberPointerType *MPT) { + assert(MPT->isMemberFunctionPointer()); + const FunctionProtoType *FPT = + MPT->getPointeeType()->castAs<FunctionProtoType>(); + const CXXRecordDecl *RD = MPT->getClass()->getAsCXXRecordDecl(); + llvm::FunctionType *FTy = + CGM.getTypes().GetFunctionType( + CGM.getTypes().arrangeCXXMethodType(RD, FPT)); + CGBuilderTy &Builder = CGF.Builder; + + MSInheritanceModel 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 = NULL; + llvm::Value *VirtualBaseAdjustmentOffset = NULL; + llvm::Value *VBPtrOffset = NULL; + if (MemPtr->getType()->isStructTy()) { + // We need to extract values. + unsigned I = 0; + FunctionPointer = Builder.CreateExtractValue(MemPtr, I++); + if (hasNonVirtualBaseAdjustmentField(MPT, Inheritance)) + NonVirtualBaseAdjustment = Builder.CreateExtractValue(MemPtr, I++); + if (hasVBPtrOffsetField(Inheritance)) + VBPtrOffset = Builder.CreateExtractValue(MemPtr, I++); + if (hasVirtualBaseAdjustmentField(Inheritance)) + VirtualBaseAdjustmentOffset = Builder.CreateExtractValue(MemPtr, I++); + } + + if (VirtualBaseAdjustmentOffset) { + This = AdjustVirtualBase(CGF, 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); +} |
