diff options
Diffstat (limited to 'lib/CodeGen/MicrosoftCXXABI.cpp')
| -rw-r--r-- | lib/CodeGen/MicrosoftCXXABI.cpp | 1268 |
1 files changed, 1024 insertions, 244 deletions
diff --git a/lib/CodeGen/MicrosoftCXXABI.cpp b/lib/CodeGen/MicrosoftCXXABI.cpp index c067fab1e921..de30883c545f 100644 --- a/lib/CodeGen/MicrosoftCXXABI.cpp +++ b/lib/CodeGen/MicrosoftCXXABI.cpp @@ -17,12 +17,16 @@ #include "CGCXXABI.h" #include "CGVTables.h" #include "CodeGenModule.h" +#include "CodeGenTypes.h" +#include "TargetInfo.h" #include "clang/AST/Decl.h" #include "clang/AST/DeclCXX.h" +#include "clang/AST/StmtCXX.h" #include "clang/AST/VTableBuilder.h" #include "llvm/ADT/StringExtras.h" #include "llvm/ADT/StringSet.h" #include "llvm/IR/CallSite.h" +#include "llvm/IR/Intrinsics.h" using namespace clang; using namespace CodeGen; @@ -40,7 +44,8 @@ public: MicrosoftCXXABI(CodeGenModule &CGM) : CGCXXABI(CGM), BaseClassDescriptorType(nullptr), ClassHierarchyDescriptorType(nullptr), - CompleteObjectLocatorType(nullptr) {} + CompleteObjectLocatorType(nullptr), CatchableTypeType(nullptr), + ThrowInfoType(nullptr), CatchHandlerTypeType(nullptr) {} bool HasThisReturn(GlobalDecl GD) const override; bool hasMostDerivedReturn(GlobalDecl GD) const override; @@ -71,11 +76,16 @@ public: const CXXDestructorDecl *Dtor) override; void emitRethrow(CodeGenFunction &CGF, bool isNoReturn) override; + void emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) override; + + void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) override; llvm::GlobalVariable *getMSCompleteObjectLocator(const CXXRecordDecl *RD, const VPtrInfo *Info); llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) override; + llvm::Constant * + getAddrOfCXXCatchHandlerType(QualType Ty, QualType CatchHandlerType) override; bool shouldTypeidBeNullChecked(bool IsDeref, QualType SrcRecordTy) override; void EmitBadTypeidCall(CodeGenFunction &CGF) override; @@ -225,7 +235,7 @@ public: assert(GD.getDtorType() == Dtor_Deleting && "Only deleting destructor thunks are available in this ABI"); CallArgs.add(RValue::get(getStructorImplicitParamValue(CGF)), - CGM.getContext().IntTy); + getContext().IntTy); } void emitVirtualInheritanceTables(const CXXRecordDecl *RD) override; @@ -410,6 +420,9 @@ public: if (!isImageRelative()) return PtrVal; + if (PtrVal->isNullValue()) + return llvm::Constant::getNullValue(CGM.IntTy); + llvm::Constant *ImageBaseAsInt = llvm::ConstantExpr::getPtrToInt(getImageBase(), CGM.IntPtrTy); llvm::Constant *PtrValAsInt = @@ -467,6 +480,10 @@ private: return GetVBaseOffsetFromVBPtr(CGF, Base, VBPOffset, VBTOffset, VBPtr); } + std::pair<llvm::Value *, llvm::Value *> + performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value, + QualType SrcRecordTy); + /// \brief Performs a full virtual base adjustment. Used to dereference /// pointers to members of virtual bases. llvm::Value *AdjustVirtualBase(CodeGenFunction &CGF, const Expr *E, @@ -479,7 +496,8 @@ private: llvm::Constant *EmitFullMemberPointer(llvm::Constant *FirstField, bool IsMemberFunction, const CXXRecordDecl *RD, - CharUnits NonVirtualBaseAdjustment); + CharUnits NonVirtualBaseAdjustment, + unsigned VBTableIndex); llvm::Constant *BuildMemberPointer(const CXXRecordDecl *RD, const CXXMethodDecl *MD, @@ -556,6 +574,94 @@ public: void emitCXXStructor(const CXXMethodDecl *MD, StructorType Type) override; + llvm::StructType *getCatchHandlerTypeType() { + if (!CatchHandlerTypeType) { + llvm::Type *FieldTypes[] = { + CGM.IntTy, // Flags + CGM.Int8PtrTy, // TypeDescriptor + }; + CatchHandlerTypeType = llvm::StructType::create( + CGM.getLLVMContext(), FieldTypes, "eh.CatchHandlerType"); + } + return CatchHandlerTypeType; + } + + llvm::StructType *getCatchableTypeType() { + if (CatchableTypeType) + return CatchableTypeType; + llvm::Type *FieldTypes[] = { + CGM.IntTy, // Flags + getImageRelativeType(CGM.Int8PtrTy), // TypeDescriptor + CGM.IntTy, // NonVirtualAdjustment + CGM.IntTy, // OffsetToVBPtr + CGM.IntTy, // VBTableIndex + CGM.IntTy, // Size + getImageRelativeType(CGM.Int8PtrTy) // CopyCtor + }; + CatchableTypeType = llvm::StructType::create( + CGM.getLLVMContext(), FieldTypes, "eh.CatchableType"); + return CatchableTypeType; + } + + llvm::StructType *getCatchableTypeArrayType(uint32_t NumEntries) { + llvm::StructType *&CatchableTypeArrayType = + CatchableTypeArrayTypeMap[NumEntries]; + if (CatchableTypeArrayType) + return CatchableTypeArrayType; + + llvm::SmallString<23> CTATypeName("eh.CatchableTypeArray."); + CTATypeName += llvm::utostr(NumEntries); + llvm::Type *CTType = + getImageRelativeType(getCatchableTypeType()->getPointerTo()); + llvm::Type *FieldTypes[] = { + CGM.IntTy, // NumEntries + llvm::ArrayType::get(CTType, NumEntries) // CatchableTypes + }; + CatchableTypeArrayType = + llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, CTATypeName); + return CatchableTypeArrayType; + } + + llvm::StructType *getThrowInfoType() { + if (ThrowInfoType) + return ThrowInfoType; + llvm::Type *FieldTypes[] = { + CGM.IntTy, // Flags + getImageRelativeType(CGM.Int8PtrTy), // CleanupFn + getImageRelativeType(CGM.Int8PtrTy), // ForwardCompat + getImageRelativeType(CGM.Int8PtrTy) // CatchableTypeArray + }; + ThrowInfoType = llvm::StructType::create(CGM.getLLVMContext(), FieldTypes, + "eh.ThrowInfo"); + return ThrowInfoType; + } + + llvm::Constant *getThrowFn() { + // _CxxThrowException is passed an exception object and a ThrowInfo object + // which describes the exception. + llvm::Type *Args[] = {CGM.Int8PtrTy, getThrowInfoType()->getPointerTo()}; + llvm::FunctionType *FTy = + llvm::FunctionType::get(CGM.VoidTy, Args, /*IsVarArgs=*/false); + auto *Fn = cast<llvm::Function>( + CGM.CreateRuntimeFunction(FTy, "_CxxThrowException")); + // _CxxThrowException is stdcall on 32-bit x86 platforms. + if (CGM.getTarget().getTriple().getArch() == llvm::Triple::x86) + Fn->setCallingConv(llvm::CallingConv::X86_StdCall); + return Fn; + } + + llvm::Function *getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD, + CXXCtorType CT); + + llvm::Constant *getCatchableType(QualType T, + uint32_t NVOffset = 0, + int32_t VBPtrOffset = -1, + uint32_t VBIndex = 0); + + llvm::GlobalVariable *getCatchableTypeArray(QualType T); + + llvm::GlobalVariable *getThrowInfo(QualType T) override; + private: typedef std::pair<const CXXRecordDecl *, CharUnits> VFTableIdTy; typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalVariable *> VTablesMapTy; @@ -582,11 +688,20 @@ private: /// Map from DeclContext to the current guard variable. We assume that the /// AST is visited in source code order. llvm::DenseMap<const DeclContext *, GuardInfo> GuardVariableMap; + llvm::DenseMap<const DeclContext *, GuardInfo> ThreadLocalGuardVariableMap; + llvm::DenseMap<const DeclContext *, unsigned> ThreadSafeGuardNumMap; llvm::DenseMap<size_t, llvm::StructType *> TypeDescriptorTypeMap; llvm::StructType *BaseClassDescriptorType; llvm::StructType *ClassHierarchyDescriptorType; llvm::StructType *CompleteObjectLocatorType; + + llvm::DenseMap<QualType, llvm::GlobalVariable *> CatchableTypeArrays; + + llvm::StructType *CatchableTypeType; + llvm::DenseMap<uint32_t, llvm::StructType *> CatchableTypeArrayTypeMap; + llvm::StructType *ThrowInfoType; + llvm::StructType *CatchHandlerTypeType; }; } @@ -667,55 +782,73 @@ void MicrosoftCXXABI::emitVirtualObjectDelete(CodeGenFunction &CGF, 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); + llvm::Value *Args[] = { + llvm::ConstantPointerNull::get(CGM.Int8PtrTy), + llvm::ConstantPointerNull::get(getThrowInfoType()->getPointerTo())}; + auto *Fn = getThrowFn(); if (isNoReturn) CGF.EmitNoreturnRuntimeCallOrInvoke(Fn, Args); else CGF.EmitRuntimeCallOrInvoke(Fn, Args); } -/// \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."); +namespace { +struct CallEndCatchMSVC : EHScopeStack::Cleanup { + CallEndCatchMSVC() {} + void Emit(CodeGenFunction &CGF, Flags flags) override { + CGF.EmitNounwindRuntimeCall( + CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_endcatch)); + } +}; } -static std::pair<llvm::Value *, llvm::Value *> -performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value, - QualType SrcRecordTy) { +void MicrosoftCXXABI::emitBeginCatch(CodeGenFunction &CGF, + const CXXCatchStmt *S) { + // In the MS ABI, the runtime handles the copy, and the catch handler is + // responsible for destruction. + VarDecl *CatchParam = S->getExceptionDecl(); + llvm::Value *Exn = CGF.getExceptionFromSlot(); + llvm::Function *BeginCatch = + CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_begincatch); + + // If this is a catch-all or the catch parameter is unnamed, we don't need to + // emit an alloca to the object. + if (!CatchParam || !CatchParam->getDeclName()) { + llvm::Value *Args[2] = {Exn, llvm::Constant::getNullValue(CGF.Int8PtrTy)}; + CGF.EmitNounwindRuntimeCall(BeginCatch, Args); + CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalCleanup); + return; + } + + CodeGenFunction::AutoVarEmission var = CGF.EmitAutoVarAlloca(*CatchParam); + llvm::Value *ParamAddr = + CGF.Builder.CreateBitCast(var.getObjectAddress(CGF), CGF.Int8PtrTy); + llvm::Value *Args[2] = {Exn, ParamAddr}; + CGF.EmitNounwindRuntimeCall(BeginCatch, Args); + CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalCleanup); + CGF.EmitAutoVarCleanups(var); +} + +std::pair<llvm::Value *, llvm::Value *> +MicrosoftCXXABI::performBaseAdjustment(CodeGenFunction &CGF, llvm::Value *Value, + QualType SrcRecordTy) { Value = CGF.Builder.CreateBitCast(Value, CGF.Int8PtrTy); const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl(); + const ASTContext &Context = getContext(); - if (CGF.getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr()) + if (Context.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); + const CXXBaseSpecifier *PolymorphicBase = std::find_if( + SrcDecl->vbases_begin(), SrcDecl->vbases_end(), + [&](const CXXBaseSpecifier &Base) { + const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl(); + return Context.getASTRecordLayout(BaseDecl).hasExtendableVFPtr(); + }); + llvm::Value *Offset = GetVirtualBaseClassOffset( + CGF, Value, SrcDecl, PolymorphicBase->getType()->getAsCXXRecordDecl()); Value = CGF.Builder.CreateInBoundsGEP(Value, Offset); Offset = CGF.Builder.CreateTrunc(Offset, CGF.Int32Ty); return std::make_pair(Value, Offset); @@ -725,7 +858,7 @@ bool MicrosoftCXXABI::shouldTypeidBeNullChecked(bool IsDeref, QualType SrcRecordTy) { const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl(); return IsDeref && - !CGM.getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr(); + !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr(); } static llvm::CallSite emitRTtypeidCall(CodeGenFunction &CGF, @@ -759,7 +892,7 @@ bool MicrosoftCXXABI::shouldDynamicCastCallBeNullChecked(bool SrcIsPtr, QualType SrcRecordTy) { const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl(); return SrcIsPtr && - !CGM.getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr(); + !getContext().getASTRecordLayout(SrcDecl).hasExtendableVFPtr(); } llvm::Value *MicrosoftCXXABI::EmitDynamicCastCall( @@ -817,10 +950,11 @@ bool MicrosoftCXXABI::EmitBadCastCall(CodeGenFunction &CGF) { llvm::Value *MicrosoftCXXABI::GetVirtualBaseClassOffset( CodeGenFunction &CGF, llvm::Value *This, const CXXRecordDecl *ClassDecl, const CXXRecordDecl *BaseClassDecl) { + const ASTContext &Context = getContext(); int64_t VBPtrChars = - getContext().getASTRecordLayout(ClassDecl).getVBPtrOffset().getQuantity(); + Context.getASTRecordLayout(ClassDecl).getVBPtrOffset().getQuantity(); llvm::Value *VBPtrOffset = llvm::ConstantInt::get(CGM.PtrDiffTy, VBPtrChars); - CharUnits IntSize = getContext().getTypeSizeInChars(getContext().IntTy); + CharUnits IntSize = Context.getTypeSizeInChars(Context.IntTy); CharUnits VBTableChars = IntSize * CGM.getMicrosoftVTableContext().getVBTableIndex(ClassDecl, BaseClassDecl); @@ -947,30 +1081,52 @@ void MicrosoftCXXABI::initializeHiddenVirtualInheritanceMembers( } } +static bool hasDefaultCXXMethodCC(ASTContext &Context, + const CXXMethodDecl *MD) { + CallingConv ExpectedCallingConv = Context.getDefaultCallingConvention( + /*IsVariadic=*/false, /*IsCXXMethod=*/true); + CallingConv ActualCallingConv = + MD->getType()->getAs<FunctionProtoType>()->getCallConv(); + return ExpectedCallingConv == ActualCallingConv; +} + void MicrosoftCXXABI::EmitCXXConstructors(const CXXConstructorDecl *D) { // There's only one constructor type in this ABI. CGM.EmitGlobal(GlobalDecl(D, Ctor_Complete)); + + // Exported default constructors either have a simple call-site where they use + // the typical calling convention and have a single 'this' pointer for an + // argument -or- they get a wrapper function which appropriately thunks to the + // real default constructor. This thunk is the default constructor closure. + if (D->hasAttr<DLLExportAttr>() && D->isDefaultConstructor()) + if (!hasDefaultCXXMethodCC(getContext(), D) || D->getNumParams() != 0) { + llvm::Function *Fn = getAddrOfCXXCtorClosure(D, Ctor_DefaultClosure); + Fn->setLinkage(llvm::GlobalValue::WeakODRLinkage); + Fn->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass); + } } void MicrosoftCXXABI::EmitVBPtrStores(CodeGenFunction &CGF, const CXXRecordDecl *RD) { llvm::Value *ThisInt8Ptr = CGF.Builder.CreateBitCast(getThisValue(CGF), CGM.Int8PtrTy, "this.int8"); - const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD); + const ASTContext &Context = getContext(); + const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD); const VBTableGlobals &VBGlobals = enumerateVBTables(RD); for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) { const VPtrInfo *VBT = (*VBGlobals.VBTables)[I]; llvm::GlobalVariable *GV = VBGlobals.Globals[I]; const ASTRecordLayout &SubobjectLayout = - CGM.getContext().getASTRecordLayout(VBT->BaseWithVPtr); + Context.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); + llvm::Value *GVPtr = + CGF.Builder.CreateConstInBoundsGEP2_32(GV->getValueType(), GV, 0, 0); VBPtr = CGF.Builder.CreateBitCast(VBPtr, GVPtr->getType()->getPointerTo(0), "vbptr." + VBT->ReusingBase->getName()); CGF.Builder.CreateStore(GVPtr, VBPtr); @@ -983,7 +1139,7 @@ MicrosoftCXXABI::buildStructorSignature(const CXXMethodDecl *MD, StructorType T, // TODO: 'for base' flag if (T == StructorType::Deleting) { // The scalar deleting destructor takes an implicit int parameter. - ArgTys.push_back(CGM.getContext().IntTy); + ArgTys.push_back(getContext().IntTy); } auto *CD = dyn_cast<CXXConstructorDecl>(MD); if (!CD) @@ -996,9 +1152,9 @@ MicrosoftCXXABI::buildStructorSignature(const CXXMethodDecl *MD, StructorType T, const FunctionProtoType *FPT = CD->getType()->castAs<FunctionProtoType>(); if (Class->getNumVBases()) { if (FPT->isVariadic()) - ArgTys.insert(ArgTys.begin() + 1, CGM.getContext().IntTy); + ArgTys.insert(ArgTys.begin() + 1, getContext().IntTy); else - ArgTys.push_back(CGM.getContext().IntTy); + ArgTys.push_back(getContext().IntTy); } } @@ -1038,7 +1194,7 @@ MicrosoftCXXABI::getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) { if (ML.VBase) { const ASTRecordLayout &DerivedLayout = - CGM.getContext().getASTRecordLayout(MD->getParent()); + getContext().getASTRecordLayout(MD->getParent()); Adjustment += DerivedLayout.getVBaseClassOffset(ML.VBase); } @@ -1104,7 +1260,7 @@ llvm::Value *MicrosoftCXXABI::adjustThisArgumentForVirtualFunctionCall( // 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, + This = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, This, StaticOffset.getQuantity()); } } @@ -1159,8 +1315,8 @@ llvm::Value *MicrosoftCXXABI::adjustThisParameterInVirtualFunctionPrologue( This = CGF.Builder.CreateBitCast(This, charPtrTy); assert(Adjustment.isPositive()); - This = - CGF.Builder.CreateConstInBoundsGEP1_32(This, -Adjustment.getQuantity()); + This = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, This, + -Adjustment.getQuantity()); return CGF.Builder.CreateBitCast(This, thisTy); } @@ -1280,7 +1436,7 @@ llvm::Value *MicrosoftCXXABI::getVTableAddressPointInStructor( llvm::GlobalValue *VTableAddressPoint = VFTablesMap[ID]; if (!VTableAddressPoint) { assert(Base.getBase()->getNumVBases() && - !CGM.getContext().getASTRecordLayout(Base.getBase()).hasOwnVFPtr()); + !getContext().getASTRecordLayout(Base.getBase()).hasOwnVFPtr()); } return VTableAddressPoint; } @@ -1336,98 +1492,96 @@ llvm::GlobalVariable *MicrosoftCXXABI::getAddrOfVTable(const CXXRecordDecl *RD, #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; + VPtrInfo *const *VFPtrI = + std::find_if(VFPtrs.begin(), VFPtrs.end(), [&](VPtrInfo *VPI) { + return VPI->FullOffsetInMDC == VPtrOffset; + }); + if (VFPtrI == VFPtrs.end()) { + VFTablesMap[ID] = nullptr; + return nullptr; + } + VPtrInfo *VFPtr = *VFPtrI; + + SmallString<256> VFTableName; + mangleVFTableName(getMangleContext(), RD, VFPtr, VFTableName); + + llvm::GlobalValue::LinkageTypes VFTableLinkage = CGM.getVTableLinkage(RD); + bool VFTableComesFromAnotherTU = + llvm::GlobalValue::isAvailableExternallyLinkage(VFTableLinkage) || + llvm::GlobalValue::isExternalLinkage(VFTableLinkage); + bool VTableAliasIsRequred = + !VFTableComesFromAnotherTU && getContext().getLangOpts().RTTIData; + + if (llvm::GlobalValue *VFTable = + CGM.getModule().getNamedGlobal(VFTableName)) { + VFTablesMap[ID] = VFTable; + return VTableAliasIsRequred + ? cast<llvm::GlobalVariable>( + cast<llvm::GlobalAlias>(VFTable)->getBaseObject()) + : cast<llvm::GlobalVariable>(VFTable); + } + + uint64_t NumVTableSlots = + VTContext.getVFTableLayout(RD, VFPtr->FullOffsetInMDC) + .getNumVTableComponents(); + llvm::GlobalValue::LinkageTypes VTableLinkage = + VTableAliasIsRequred ? llvm::GlobalValue::PrivateLinkage : VFTableLinkage; + + StringRef VTableName = VTableAliasIsRequred ? StringRef() : VFTableName.str(); + + llvm::ArrayType *VTableType = + llvm::ArrayType::get(CGM.Int8PtrTy, NumVTableSlots); + + // Create a backing variable for the contents of VTable. The VTable may + // or may not include space for a pointer to RTTI data. + llvm::GlobalValue *VFTable; + VTable = new llvm::GlobalVariable(CGM.getModule(), VTableType, + /*isConstant=*/true, VTableLinkage, + /*Initializer=*/nullptr, VTableName); + VTable->setUnnamedAddr(true); + + llvm::Comdat *C = nullptr; + if (!VFTableComesFromAnotherTU && + (llvm::GlobalValue::isWeakForLinker(VFTableLinkage) || + (llvm::GlobalValue::isLocalLinkage(VFTableLinkage) && + VTableAliasIsRequred))) + C = CGM.getModule().getOrInsertComdat(VFTableName.str()); + + // Only insert a pointer into the VFTable for RTTI data if we are not + // importing it. We never reference the RTTI data directly so there is no + // need to make room for it. + if (VTableAliasIsRequred) { + llvm::Value *GEPIndices[] = {llvm::ConstantInt::get(CGM.IntTy, 0), + llvm::ConstantInt::get(CGM.IntTy, 1)}; + // Create a GEP which points just after the first entry in the VFTable, + // this should be the location of the first virtual method. + llvm::Constant *VTableGEP = llvm::ConstantExpr::getInBoundsGetElementPtr( + VTable->getValueType(), VTable, GEPIndices); + if (llvm::GlobalValue::isWeakForLinker(VFTableLinkage)) { + VFTableLinkage = llvm::GlobalValue::ExternalLinkage; + if (C) + C->setSelectionKind(llvm::Comdat::Largest); } - break; + VFTable = llvm::GlobalAlias::create( + cast<llvm::PointerType>(VTableGEP->getType()), VFTableLinkage, + VFTableName.str(), VTableGEP, &CGM.getModule()); + VFTable->setUnnamedAddr(true); + } else { + // We don't need a GlobalAlias to be a symbol for the VTable if we won't + // be referencing any RTTI data. + // The GlobalVariable will end up being an appropriate definition of the + // VFTable. + VFTable = VTable; } + if (C) + VTable->setComdat(C); + + if (RD->hasAttr<DLLImportAttr>()) + VFTable->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass); + else if (RD->hasAttr<DLLExportAttr>()) + VFTable->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass); + VFTablesMap[ID] = VFTable; return VTable; } @@ -1464,7 +1618,7 @@ llvm::Value *MicrosoftCXXABI::EmitVirtualDestructorCall( llvm::Type *Ty = CGF.CGM.getTypes().GetFunctionType(*FInfo); llvm::Value *Callee = getVirtualFunctionPointer(CGF, GD, This, Ty); - ASTContext &Context = CGF.getContext(); + ASTContext &Context = getContext(); llvm::Value *ImplicitParam = llvm::ConstantInt::get( llvm::IntegerType::getInt32Ty(CGF.getLLVMContext()), DtorType == Dtor_Deleting); @@ -1530,6 +1684,8 @@ llvm::Function *MicrosoftCXXABI::EmitVirtualMemPtrThunk( ThunkFn->setLinkage(MD->isExternallyVisible() ? llvm::GlobalValue::LinkOnceODRLinkage : llvm::GlobalValue::InternalLinkage); + if (MD->isExternallyVisible()) + ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName())); CGM.SetLLVMFunctionAttributes(MD, FnInfo, ThunkFn); CGM.SetLLVMFunctionAttributesForDefinition(MD, ThunkFn); @@ -1576,7 +1732,8 @@ void MicrosoftCXXABI::emitVirtualInheritanceTables(const CXXRecordDecl *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); + if (GV->isDeclaration()) + emitVBTableDefinition(*VBT, RD, GV); } } @@ -1603,6 +1760,9 @@ MicrosoftCXXABI::getAddrOfVBTable(const VPtrInfo &VBT, const CXXRecordDecl *RD, else if (RD->hasAttr<DLLExportAttr>()) GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass); + if (!GV->hasExternalLinkage()) + emitVBTableDefinition(VBT, RD, GV); + return GV; } @@ -1615,9 +1775,8 @@ void MicrosoftCXXABI::emitVBTableDefinition(const VPtrInfo &VBT, "should only emit vbtables for classes with vbtables"); const ASTRecordLayout &BaseLayout = - CGM.getContext().getASTRecordLayout(VBT.BaseWithVPtr); - const ASTRecordLayout &DerivedLayout = - CGM.getContext().getASTRecordLayout(RD); + getContext().getASTRecordLayout(VBT.BaseWithVPtr); + const ASTRecordLayout &DerivedLayout = getContext().getASTRecordLayout(RD); SmallVector<llvm::Constant *, 4> Offsets(1 + ReusingBase->getNumVBases(), nullptr); @@ -1651,9 +1810,6 @@ void MicrosoftCXXABI::emitVBTableDefinition(const VPtrInfo &VBT, 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, @@ -1709,8 +1865,8 @@ MicrosoftCXXABI::performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret, if (RA.Virtual.Microsoft.VBIndex) { assert(RA.Virtual.Microsoft.VBIndex > 0); - int32_t IntSize = - getContext().getTypeSizeInChars(getContext().IntTy).getQuantity(); + const ASTContext &Context = getContext(); + int32_t IntSize = Context.getTypeSizeInChars(Context.IntTy).getQuantity(); llvm::Value *VBPtr; llvm::Value *VBaseOffset = GetVBaseOffsetFromVBPtr(CGF, V, RA.Virtual.Microsoft.VBPtrOffset, @@ -1719,7 +1875,7 @@ MicrosoftCXXABI::performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret, } if (RA.NonVirtual) - V = CGF.Builder.CreateConstInBoundsGEP1_32(V, RA.NonVirtual); + V = CGF.Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, V, RA.NonVirtual); // Cast back to the original type. return CGF.Builder.CreateBitCast(V, Ret->getType()); @@ -1835,18 +1991,10 @@ void MicrosoftCXXABI::EmitThreadLocalInitFuncs( 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); + if (llvm::Comdat *C = GV->getComdat()) AddToXDU(F)->setComdat(C); - } else { + else NonComdatInits.push_back(F); - } } if (!NonComdatInits.empty()) { @@ -1868,6 +2016,81 @@ LValue MicrosoftCXXABI::EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, return LValue(); } +static llvm::GlobalVariable *getInitThreadEpochPtr(CodeGenModule &CGM) { + StringRef VarName("_Init_thread_epoch"); + if (auto *GV = CGM.getModule().getNamedGlobal(VarName)) + return GV; + auto *GV = new llvm::GlobalVariable( + CGM.getModule(), CGM.IntTy, + /*Constant=*/false, llvm::GlobalVariable::ExternalLinkage, + /*Initializer=*/nullptr, VarName, + /*InsertBefore=*/nullptr, llvm::GlobalVariable::GeneralDynamicTLSModel); + GV->setAlignment(CGM.getTarget().getIntAlign() / 8); + return GV; +} + +static llvm::Constant *getInitThreadHeaderFn(CodeGenModule &CGM) { + llvm::FunctionType *FTy = + llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()), + CGM.IntTy->getPointerTo(), /*isVarArg=*/false); + return CGM.CreateRuntimeFunction( + FTy, "_Init_thread_header", + llvm::AttributeSet::get(CGM.getLLVMContext(), + llvm::AttributeSet::FunctionIndex, + llvm::Attribute::NoUnwind)); +} + +static llvm::Constant *getInitThreadFooterFn(CodeGenModule &CGM) { + llvm::FunctionType *FTy = + llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()), + CGM.IntTy->getPointerTo(), /*isVarArg=*/false); + return CGM.CreateRuntimeFunction( + FTy, "_Init_thread_footer", + llvm::AttributeSet::get(CGM.getLLVMContext(), + llvm::AttributeSet::FunctionIndex, + llvm::Attribute::NoUnwind)); +} + +static llvm::Constant *getInitThreadAbortFn(CodeGenModule &CGM) { + llvm::FunctionType *FTy = + llvm::FunctionType::get(llvm::Type::getVoidTy(CGM.getLLVMContext()), + CGM.IntTy->getPointerTo(), /*isVarArg=*/false); + return CGM.CreateRuntimeFunction( + FTy, "_Init_thread_abort", + llvm::AttributeSet::get(CGM.getLLVMContext(), + llvm::AttributeSet::FunctionIndex, + llvm::Attribute::NoUnwind)); +} + +namespace { +struct ResetGuardBit : EHScopeStack::Cleanup { + llvm::GlobalVariable *Guard; + unsigned GuardNum; + ResetGuardBit(llvm::GlobalVariable *Guard, unsigned GuardNum) + : Guard(Guard), GuardNum(GuardNum) {} + + void Emit(CodeGenFunction &CGF, Flags flags) override { + // Reset the bit in the mask so that the static variable may be + // reinitialized. + CGBuilderTy &Builder = CGF.Builder; + llvm::LoadInst *LI = Builder.CreateLoad(Guard); + llvm::ConstantInt *Mask = + llvm::ConstantInt::get(CGF.IntTy, ~(1U << GuardNum)); + Builder.CreateStore(Builder.CreateAnd(LI, Mask), Guard); + } +}; + +struct CallInitThreadAbort : EHScopeStack::Cleanup { + llvm::GlobalVariable *Guard; + CallInitThreadAbort(llvm::GlobalVariable *Guard) : Guard(Guard) {} + + void Emit(CodeGenFunction &CGF, Flags flags) override { + // Calling _Init_thread_abort will reset the guard's state. + CGF.EmitNounwindRuntimeCall(getInitThreadAbortFn(CGF.CGM), Guard); + } +}; +} + void MicrosoftCXXABI::EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D, llvm::GlobalVariable *GV, bool PerformInit) { @@ -1875,91 +2098,161 @@ void MicrosoftCXXABI::EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D, 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); + llvm::Function *F = CGF.CurFn; + F->setLinkage(llvm::GlobalValue::LinkOnceODRLinkage); + F->setComdat(CGM.getModule().getOrInsertComdat(F->getName())); 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. + bool ThreadlocalStatic = D.getTLSKind(); + bool ThreadsafeStatic = getContext().getLangOpts().ThreadsafeStatics; - if (D.getTLSKind()) - CGM.ErrorUnsupported(&D, "dynamic TLS initialization"); + // Thread-safe static variables which aren't thread-specific have a + // per-variable guard. + bool HasPerVariableGuard = ThreadsafeStatic && !ThreadlocalStatic; CGBuilderTy &Builder = CGF.Builder; llvm::IntegerType *GuardTy = CGF.Int32Ty; llvm::ConstantInt *Zero = llvm::ConstantInt::get(GuardTy, 0); // Get the guard variable for this function if we have one already. - GuardInfo *GI = &GuardVariableMap[D.getDeclContext()]; - - unsigned BitIndex; - if (D.isStaticLocal() && D.isExternallyVisible()) { + GuardInfo *GI = nullptr; + if (ThreadlocalStatic) + GI = &ThreadLocalGuardVariableMap[D.getDeclContext()]; + else if (!ThreadsafeStatic) + GI = &GuardVariableMap[D.getDeclContext()]; + + llvm::GlobalVariable *GuardVar = GI ? GI->Guard : nullptr; + unsigned GuardNum; + if (D.isExternallyVisible()) { // Externally visible variables have to be numbered in Sema to properly // handle unreachable VarDecls. - BitIndex = getContext().getStaticLocalNumber(&D); - assert(BitIndex > 0); - BitIndex--; + GuardNum = getContext().getStaticLocalNumber(&D); + assert(GuardNum > 0); + GuardNum--; + } else if (HasPerVariableGuard) { + GuardNum = ThreadSafeGuardNumMap[D.getDeclContext()]++; } else { // Non-externally visible variables are numbered here in CodeGen. - BitIndex = GI->BitIndex++; + GuardNum = GI->BitIndex++; } - if (BitIndex >= 32) { + if (!HasPerVariableGuard && GuardNum >= 32) { if (D.isExternallyVisible()) ErrorUnsupportedABI(CGF, "more than 32 guarded initializations"); - BitIndex %= 32; - GI->Guard = nullptr; + GuardNum %= 32; + GuardVar = nullptr; } - // Lazily create the i32 bitfield for this function. - if (!GI->Guard) { + if (!GuardVar) { // Mangle the name for the guard. SmallString<256> GuardName; { llvm::raw_svector_ostream Out(GuardName); - getMangleContext().mangleStaticGuardVariable(&D, Out); + if (HasPerVariableGuard) + getMangleContext().mangleThreadSafeStaticGuardVariable(&D, GuardNum, + Out); + else + 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, + GuardVar = + new llvm::GlobalVariable(CGM.getModule(), GuardTy, /*isConstant=*/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); + GuardVar->setVisibility(GV->getVisibility()); + GuardVar->setDLLStorageClass(GV->getDLLStorageClass()); + if (GuardVar->isWeakForLinker()) + GuardVar->setComdat( + CGM.getModule().getOrInsertComdat(GuardVar->getName())); + if (D.getTLSKind()) + GuardVar->setThreadLocal(true); + if (GI && !HasPerVariableGuard) + GI->Guard = GuardVar; + } + + assert(GuardVar->getLinkage() == GV->getLinkage() && + "static local from the same function had different linkage"); + + if (!HasPerVariableGuard) { + // Pseudo code for the test: + // if (!(GuardVar & MyGuardBit)) { + // GuardVar |= MyGuardBit; + // ... initialize the object ...; + // } + + // Test our bit from the guard variable. + llvm::ConstantInt *Bit = llvm::ConstantInt::get(GuardTy, 1U << GuardNum); + llvm::LoadInst *LI = Builder.CreateLoad(GuardVar); + 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), GuardVar); + CGF.EHStack.pushCleanup<ResetGuardBit>(EHCleanup, GuardVar, GuardNum); + CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit); + CGF.PopCleanupBlock(); + Builder.CreateBr(EndBlock); - // 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); + } else { + // Pseudo code for the test: + // if (TSS > _Init_thread_epoch) { + // _Init_thread_header(&TSS); + // if (TSS == -1) { + // ... initialize the object ...; + // _Init_thread_footer(&TSS); + // } + // } + // + // The algorithm is almost identical to what can be found in the appendix + // found in N2325. + + unsigned IntAlign = CGM.getTarget().getIntAlign() / 8; + + // This BasicBLock determines whether or not we have any work to do. + llvm::LoadInst *FirstGuardLoad = + Builder.CreateAlignedLoad(GuardVar, IntAlign); + FirstGuardLoad->setOrdering(llvm::AtomicOrdering::Unordered); + llvm::LoadInst *InitThreadEpoch = + Builder.CreateLoad(getInitThreadEpochPtr(CGM)); + llvm::Value *IsUninitialized = + Builder.CreateICmpSGT(FirstGuardLoad, InitThreadEpoch); + llvm::BasicBlock *AttemptInitBlock = CGF.createBasicBlock("init.attempt"); + llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end"); + Builder.CreateCondBr(IsUninitialized, AttemptInitBlock, EndBlock); + + // This BasicBlock attempts to determine whether or not this thread is + // responsible for doing the initialization. + CGF.EmitBlock(AttemptInitBlock); + CGF.EmitNounwindRuntimeCall(getInitThreadHeaderFn(CGM), GuardVar); + llvm::LoadInst *SecondGuardLoad = + Builder.CreateAlignedLoad(GuardVar, IntAlign); + SecondGuardLoad->setOrdering(llvm::AtomicOrdering::Unordered); + llvm::Value *ShouldDoInit = + Builder.CreateICmpEQ(SecondGuardLoad, getAllOnesInt()); + llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init"); + Builder.CreateCondBr(ShouldDoInit, InitBlock, EndBlock); + + // Ok, we ended up getting selected as the initializing thread. + CGF.EmitBlock(InitBlock); + CGF.EHStack.pushCleanup<CallInitThreadAbort>(EHCleanup, GuardVar); + CGF.EmitCXXGlobalVarDeclInit(D, GV, PerformInit); + CGF.PopCleanupBlock(); + CGF.EmitNounwindRuntimeCall(getInitThreadFooterFn(CGM), GuardVar); + Builder.CreateBr(EndBlock); - // Continue. - CGF.EmitBlock(EndBlock); + CGF.EmitBlock(EndBlock); + } } bool MicrosoftCXXABI::isZeroInitializable(const MemberPointerType *MPT) { @@ -2040,8 +2333,8 @@ llvm::Constant * MicrosoftCXXABI::EmitFullMemberPointer(llvm::Constant *FirstField, bool IsMemberFunction, const CXXRecordDecl *RD, - CharUnits NonVirtualBaseAdjustment) -{ + CharUnits NonVirtualBaseAdjustment, + unsigned VBTableIndex) { MSInheritanceAttr::Spelling Inheritance = RD->getMSInheritanceModel(); // Single inheritance class member pointer are represented as scalars instead @@ -2065,7 +2358,7 @@ MicrosoftCXXABI::EmitFullMemberPointer(llvm::Constant *FirstField, // The rest of the fields are adjusted by conversions to a more derived class. if (MSInheritanceAttr::hasVBTableOffsetField(Inheritance)) - fields.push_back(getZeroInt()); + fields.push_back(llvm::ConstantInt::get(CGM.IntTy, VBTableIndex)); return llvm::ConstantStruct::getAnon(fields); } @@ -2077,7 +2370,7 @@ MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT, llvm::Constant *FirstField = llvm::ConstantInt::get(CGM.IntTy, offset.getQuantity()); return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/false, RD, - CharUnits::Zero()); + CharUnits::Zero(), /*VBTableIndex=*/0); } llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const CXXMethodDecl *MD) { @@ -2113,6 +2406,7 @@ MicrosoftCXXABI::BuildMemberPointer(const CXXRecordDecl *RD, RD = RD->getMostRecentDecl(); CodeGenTypes &Types = CGM.getTypes(); + unsigned VBTableIndex = 0; llvm::Constant *FirstField; const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>(); if (!MD->isVirtual()) { @@ -2129,8 +2423,6 @@ MicrosoftCXXABI::BuildMemberPointer(const CXXRecordDecl *RD, 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 " @@ -2139,21 +2431,22 @@ MicrosoftCXXABI::BuildMemberPointer(const CXXRecordDecl *RD, } 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 { + auto &VTableContext = CGM.getMicrosoftVTableContext(); + MicrosoftVTableContext::MethodVFTableLocation ML = + VTableContext.getMethodVFTableLocation(MD); 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; + if (ML.VBase) + VBTableIndex = VTableContext.getVBTableIndex(RD, ML.VBase) * 4; } } // The rest of the fields are common with data member pointers. return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/true, RD, - NonVirtualBaseAdjustment); + NonVirtualBaseAdjustment, VBTableIndex); } /// Member pointers are the same if they're either bitwise identical *or* both @@ -2867,7 +3160,11 @@ llvm::GlobalVariable *MSRTTIBuilder::getClassHierarchyDescriptor() { auto Type = ABI.getClassHierarchyDescriptorType(); auto CHD = new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage, /*Initializer=*/nullptr, - MangledName.c_str()); + StringRef(MangledName)); + if (CHD->isWeakForLinker()) + CHD->setComdat(CGM.getModule().getOrInsertComdat(CHD->getName())); + + auto *Bases = getBaseClassArray(Classes); // Initialize the base class ClassHierarchyDescriptor. llvm::Constant *Fields[] = { @@ -2875,7 +3172,7 @@ llvm::GlobalVariable *MSRTTIBuilder::getClassHierarchyDescriptor() { llvm::ConstantInt::get(CGM.IntTy, Flags), llvm::ConstantInt::get(CGM.IntTy, Classes.size()), ABI.getImageRelativeConstant(llvm::ConstantExpr::getInBoundsGetElementPtr( - getBaseClassArray(Classes), + Bases->getValueType(), Bases, llvm::ArrayRef<llvm::Value *>(GEPIndices))), }; CHD->setInitializer(llvm::ConstantStruct::get(Type, Fields)); @@ -2898,9 +3195,12 @@ MSRTTIBuilder::getBaseClassArray(SmallVectorImpl<MSRTTIClass> &Classes) { 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()); + auto *BCA = + new llvm::GlobalVariable(Module, ArrType, + /*Constant=*/true, Linkage, + /*Initializer=*/nullptr, StringRef(MangledName)); + if (BCA->isWeakForLinker()) + BCA->setComdat(CGM.getModule().getOrInsertComdat(BCA->getName())); // Initialize the BaseClassArray. SmallVector<llvm::Constant *, 8> BaseClassArrayData; @@ -2938,9 +3238,11 @@ MSRTTIBuilder::getBaseClassDescriptor(const MSRTTIClass &Class) { // 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()); + auto BCD = + new llvm::GlobalVariable(Module, Type, /*Constant=*/true, Linkage, + /*Initializer=*/nullptr, StringRef(MangledName)); + if (BCD->isWeakForLinker()) + BCD->setComdat(CGM.getModule().getOrInsertComdat(BCD->getName())); // Initialize the BaseClassDescriptor. llvm::Constant *Fields[] = { @@ -2984,7 +3286,7 @@ MSRTTIBuilder::getCompleteObjectLocator(const VPtrInfo *Info) { // 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()); + /*Initializer=*/nullptr, StringRef(MangledName)); // Initialize the CompleteObjectLocator. llvm::Constant *Fields[] = { @@ -3000,15 +3302,91 @@ MSRTTIBuilder::getCompleteObjectLocator(const VPtrInfo *Info) { if (!ABI.isImageRelative()) FieldsRef = FieldsRef.drop_back(); COL->setInitializer(llvm::ConstantStruct::get(Type, FieldsRef)); + if (COL->isWeakForLinker()) + COL->setComdat(CGM.getModule().getOrInsertComdat(COL->getName())); return COL; } +static QualType decomposeTypeForEH(ASTContext &Context, QualType T, + bool &IsConst, bool &IsVolatile) { + T = Context.getExceptionObjectType(T); + + // C++14 [except.handle]p3: + // A handler is a match for an exception object of type E if [...] + // - the handler is of type cv T or const T& where T is a pointer type and + // E is a pointer type that can be converted to T by [...] + // - a qualification conversion + IsConst = false; + IsVolatile = false; + QualType PointeeType = T->getPointeeType(); + if (!PointeeType.isNull()) { + IsConst = PointeeType.isConstQualified(); + IsVolatile = PointeeType.isVolatileQualified(); + } + + // Member pointer types like "const int A::*" are represented by having RTTI + // for "int A::*" and separately storing the const qualifier. + if (const auto *MPTy = T->getAs<MemberPointerType>()) + T = Context.getMemberPointerType(PointeeType.getUnqualifiedType(), + MPTy->getClass()); + + // Pointer types like "const int * const *" are represented by having RTTI + // for "const int **" and separately storing the const qualifier. + if (T->isPointerType()) + T = Context.getPointerType(PointeeType.getUnqualifiedType()); + + return T; +} + +llvm::Constant * +MicrosoftCXXABI::getAddrOfCXXCatchHandlerType(QualType Type, + QualType CatchHandlerType) { + // TypeDescriptors for exceptions never have qualified pointer types, + // qualifiers are stored seperately in order to support qualification + // conversions. + bool IsConst, IsVolatile; + Type = decomposeTypeForEH(getContext(), Type, IsConst, IsVolatile); + + bool IsReference = CatchHandlerType->isReferenceType(); + + uint32_t Flags = 0; + if (IsConst) + Flags |= 1; + if (IsVolatile) + Flags |= 2; + if (IsReference) + Flags |= 8; + + SmallString<256> MangledName; + { + llvm::raw_svector_ostream Out(MangledName); + getMangleContext().mangleCXXCatchHandlerType(Type, Flags, Out); + } + + if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName)) + return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy); + + llvm::Constant *Fields[] = { + llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags + getAddrOfRTTIDescriptor(Type), // TypeDescriptor + }; + llvm::StructType *CatchHandlerTypeType = getCatchHandlerTypeType(); + auto *Var = new llvm::GlobalVariable( + CGM.getModule(), CatchHandlerTypeType, /*Constant=*/true, + llvm::GlobalValue::PrivateLinkage, + llvm::ConstantStruct::get(CatchHandlerTypeType, Fields), + StringRef(MangledName)); + Var->setUnnamedAddr(true); + Var->setSection("llvm.metadata"); + return Var; +} + /// \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; + SmallString<256> MangledName; { llvm::raw_svector_ostream Out(MangledName); getMangleContext().mangleCXXRTTI(Type, Out); @@ -3019,6 +3397,7 @@ llvm::Constant *MicrosoftCXXABI::getAddrOfRTTIDescriptor(QualType Type) { return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy); // Compute the fields for the TypeDescriptor. + SmallString<256> TypeInfoString; { llvm::raw_svector_ostream Out(TypeInfoString); getMangleContext().mangleCXXRTTIName(Type, Out); @@ -3031,13 +3410,14 @@ llvm::Constant *MicrosoftCXXABI::getAddrOfRTTIDescriptor(QualType Type) { 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); + auto *Var = new llvm::GlobalVariable( + CGM.getModule(), TypeDescriptorType, /*Constant=*/false, + getLinkageForRTTI(Type), + llvm::ConstantStruct::get(TypeDescriptorType, Fields), + StringRef(MangledName)); + if (Var->isWeakForLinker()) + Var->setComdat(CGM.getModule().getOrInsertComdat(Var->getName())); + return llvm::ConstantExpr::getBitCast(Var, CGM.Int8PtrTy); } /// \brief Gets or a creates a Microsoft CompleteObjectLocator. @@ -3051,7 +3431,8 @@ 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); + llvm::Function *Fn = CGM.codegenCXXStructor(ctor, StructorType::Complete); + CGM.maybeSetTrivialComdat(*ctor, *Fn); } static void emitCXXDestructor(CodeGenModule &CGM, const CXXDestructorDecl *dtor, @@ -3077,7 +3458,9 @@ static void emitCXXDestructor(CodeGenModule &CGM, const CXXDestructorDecl *dtor, if (dtorType == StructorType::Base && !CGM.TryEmitBaseDestructorAsAlias(dtor)) return; - CGM.codegenCXXStructor(dtor, dtorType); + llvm::Function *Fn = CGM.codegenCXXStructor(dtor, dtorType); + if (Fn->isWeakForLinker()) + Fn->setComdat(CGM.getModule().getOrInsertComdat(Fn->getName())); } void MicrosoftCXXABI::emitCXXStructor(const CXXMethodDecl *MD, @@ -3088,3 +3471,400 @@ void MicrosoftCXXABI::emitCXXStructor(const CXXMethodDecl *MD, } emitCXXDestructor(CGM, cast<CXXDestructorDecl>(MD), Type); } + +llvm::Function * +MicrosoftCXXABI::getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD, + CXXCtorType CT) { + assert(CT == Ctor_CopyingClosure || CT == Ctor_DefaultClosure); + + // Calculate the mangled name. + SmallString<256> ThunkName; + llvm::raw_svector_ostream Out(ThunkName); + getMangleContext().mangleCXXCtor(CD, CT, Out); + 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().arrangeMSCtorClosure(CD, CT); + llvm::FunctionType *ThunkTy = CGM.getTypes().GetFunctionType(FnInfo); + const CXXRecordDecl *RD = CD->getParent(); + QualType RecordTy = getContext().getRecordType(RD); + llvm::Function *ThunkFn = llvm::Function::Create( + ThunkTy, getLinkageForRTTI(RecordTy), ThunkName.str(), &CGM.getModule()); + ThunkFn->setCallingConv(static_cast<llvm::CallingConv::ID>( + FnInfo.getEffectiveCallingConvention())); + bool IsCopy = CT == Ctor_CopyingClosure; + + // Start codegen. + CodeGenFunction CGF(CGM); + CGF.CurGD = GlobalDecl(CD, Ctor_Complete); + + // Build FunctionArgs. + FunctionArgList FunctionArgs; + + // A constructor always starts with a 'this' pointer as its first argument. + buildThisParam(CGF, FunctionArgs); + + // Following the 'this' pointer is a reference to the source object that we + // are copying from. + ImplicitParamDecl SrcParam( + getContext(), nullptr, SourceLocation(), &getContext().Idents.get("src"), + getContext().getLValueReferenceType(RecordTy, + /*SpelledAsLValue=*/true)); + if (IsCopy) + FunctionArgs.push_back(&SrcParam); + + // Constructors for classes which utilize virtual bases have an additional + // parameter which indicates whether or not it is being delegated to by a more + // derived constructor. + ImplicitParamDecl IsMostDerived(getContext(), nullptr, SourceLocation(), + &getContext().Idents.get("is_most_derived"), + getContext().IntTy); + // Only add the parameter to the list if thie class has virtual bases. + if (RD->getNumVBases() > 0) + FunctionArgs.push_back(&IsMostDerived); + + // Start defining the function. + CGF.StartFunction(GlobalDecl(), FnInfo.getReturnType(), ThunkFn, FnInfo, + FunctionArgs, CD->getLocation(), SourceLocation()); + EmitThisParam(CGF); + llvm::Value *This = getThisValue(CGF); + + llvm::Value *SrcVal = + IsCopy ? CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(&SrcParam), "src") + : nullptr; + + CallArgList Args; + + // Push the this ptr. + Args.add(RValue::get(This), CD->getThisType(getContext())); + + // Push the src ptr. + if (SrcVal) + Args.add(RValue::get(SrcVal), SrcParam.getType()); + + // Add the rest of the default arguments. + std::vector<Stmt *> ArgVec; + for (unsigned I = IsCopy ? 1 : 0, E = CD->getNumParams(); I != E; ++I) { + Stmt *DefaultArg = getContext().getDefaultArgExprForConstructor(CD, I); + assert(DefaultArg && "sema forgot to instantiate default args"); + ArgVec.push_back(DefaultArg); + } + + CodeGenFunction::RunCleanupsScope Cleanups(CGF); + + const auto *FPT = CD->getType()->castAs<FunctionProtoType>(); + ConstExprIterator ArgBegin(ArgVec.data()), + ArgEnd(ArgVec.data() + ArgVec.size()); + CGF.EmitCallArgs(Args, FPT, ArgBegin, ArgEnd, CD, IsCopy ? 1 : 0); + + // Insert any ABI-specific implicit constructor arguments. + unsigned ExtraArgs = addImplicitConstructorArgs(CGF, CD, Ctor_Complete, + /*ForVirtualBase=*/false, + /*Delegating=*/false, Args); + + // Call the destructor with our arguments. + llvm::Value *CalleeFn = CGM.getAddrOfCXXStructor(CD, StructorType::Complete); + const CGFunctionInfo &CalleeInfo = CGM.getTypes().arrangeCXXConstructorCall( + Args, CD, Ctor_Complete, ExtraArgs); + CGF.EmitCall(CalleeInfo, CalleeFn, ReturnValueSlot(), Args, CD); + + Cleanups.ForceCleanup(); + + // Emit the ret instruction, remove any temporary instructions created for the + // aid of CodeGen. + CGF.FinishFunction(SourceLocation()); + + return ThunkFn; +} + +llvm::Constant *MicrosoftCXXABI::getCatchableType(QualType T, + uint32_t NVOffset, + int32_t VBPtrOffset, + uint32_t VBIndex) { + assert(!T->isReferenceType()); + + CXXRecordDecl *RD = T->getAsCXXRecordDecl(); + const CXXConstructorDecl *CD = + RD ? CGM.getContext().getCopyConstructorForExceptionObject(RD) : nullptr; + CXXCtorType CT = Ctor_Complete; + if (CD) + if (!hasDefaultCXXMethodCC(getContext(), CD) || CD->getNumParams() != 1) + CT = Ctor_CopyingClosure; + + uint32_t Size = getContext().getTypeSizeInChars(T).getQuantity(); + SmallString<256> MangledName; + { + llvm::raw_svector_ostream Out(MangledName); + getMangleContext().mangleCXXCatchableType(T, CD, CT, Size, NVOffset, + VBPtrOffset, VBIndex, Out); + } + if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName)) + return getImageRelativeConstant(GV); + + // The TypeDescriptor is used by the runtime to determine if a catch handler + // is appropriate for the exception object. + llvm::Constant *TD = getImageRelativeConstant(getAddrOfRTTIDescriptor(T)); + + // The runtime is responsible for calling the copy constructor if the + // exception is caught by value. + llvm::Constant *CopyCtor; + if (CD) { + if (CT == Ctor_CopyingClosure) + CopyCtor = getAddrOfCXXCtorClosure(CD, Ctor_CopyingClosure); + else + CopyCtor = CGM.getAddrOfCXXStructor(CD, StructorType::Complete); + + CopyCtor = llvm::ConstantExpr::getBitCast(CopyCtor, CGM.Int8PtrTy); + } else { + CopyCtor = llvm::Constant::getNullValue(CGM.Int8PtrTy); + } + CopyCtor = getImageRelativeConstant(CopyCtor); + + bool IsScalar = !RD; + bool HasVirtualBases = false; + bool IsStdBadAlloc = false; // std::bad_alloc is special for some reason. + QualType PointeeType = T; + if (T->isPointerType()) + PointeeType = T->getPointeeType(); + if (const CXXRecordDecl *RD = PointeeType->getAsCXXRecordDecl()) { + HasVirtualBases = RD->getNumVBases() > 0; + if (IdentifierInfo *II = RD->getIdentifier()) + IsStdBadAlloc = II->isStr("bad_alloc") && RD->isInStdNamespace(); + } + + // Encode the relevant CatchableType properties into the Flags bitfield. + // FIXME: Figure out how bits 2 or 8 can get set. + uint32_t Flags = 0; + if (IsScalar) + Flags |= 1; + if (HasVirtualBases) + Flags |= 4; + if (IsStdBadAlloc) + Flags |= 16; + + llvm::Constant *Fields[] = { + llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags + TD, // TypeDescriptor + llvm::ConstantInt::get(CGM.IntTy, NVOffset), // NonVirtualAdjustment + llvm::ConstantInt::get(CGM.IntTy, VBPtrOffset), // OffsetToVBPtr + llvm::ConstantInt::get(CGM.IntTy, VBIndex), // VBTableIndex + llvm::ConstantInt::get(CGM.IntTy, Size), // Size + CopyCtor // CopyCtor + }; + llvm::StructType *CTType = getCatchableTypeType(); + auto *GV = new llvm::GlobalVariable( + CGM.getModule(), CTType, /*Constant=*/true, getLinkageForRTTI(T), + llvm::ConstantStruct::get(CTType, Fields), StringRef(MangledName)); + GV->setUnnamedAddr(true); + GV->setSection(".xdata"); + if (GV->isWeakForLinker()) + GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName())); + return getImageRelativeConstant(GV); +} + +llvm::GlobalVariable *MicrosoftCXXABI::getCatchableTypeArray(QualType T) { + assert(!T->isReferenceType()); + + // See if we've already generated a CatchableTypeArray for this type before. + llvm::GlobalVariable *&CTA = CatchableTypeArrays[T]; + if (CTA) + return CTA; + + // Ensure that we don't have duplicate entries in our CatchableTypeArray by + // using a SmallSetVector. Duplicates may arise due to virtual bases + // occurring more than once in the hierarchy. + llvm::SmallSetVector<llvm::Constant *, 2> CatchableTypes; + + // C++14 [except.handle]p3: + // A handler is a match for an exception object of type E if [...] + // - the handler is of type cv T or cv T& and T is an unambiguous public + // base class of E, or + // - the handler is of type cv T or const T& where T is a pointer type and + // E is a pointer type that can be converted to T by [...] + // - a standard pointer conversion (4.10) not involving conversions to + // pointers to private or protected or ambiguous classes + const CXXRecordDecl *MostDerivedClass = nullptr; + bool IsPointer = T->isPointerType(); + if (IsPointer) + MostDerivedClass = T->getPointeeType()->getAsCXXRecordDecl(); + else + MostDerivedClass = T->getAsCXXRecordDecl(); + + // Collect all the unambiguous public bases of the MostDerivedClass. + if (MostDerivedClass) { + const ASTContext &Context = getContext(); + const ASTRecordLayout &MostDerivedLayout = + Context.getASTRecordLayout(MostDerivedClass); + MicrosoftVTableContext &VTableContext = CGM.getMicrosoftVTableContext(); + SmallVector<MSRTTIClass, 8> Classes; + serializeClassHierarchy(Classes, MostDerivedClass); + Classes.front().initialize(/*Parent=*/nullptr, /*Specifier=*/nullptr); + detectAmbiguousBases(Classes); + for (const MSRTTIClass &Class : Classes) { + // Skip any ambiguous or private bases. + if (Class.Flags & + (MSRTTIClass::IsPrivateOnPath | MSRTTIClass::IsAmbiguous)) + continue; + // Write down how to convert from a derived pointer to a base pointer. + uint32_t OffsetInVBTable = 0; + int32_t VBPtrOffset = -1; + if (Class.VirtualRoot) { + OffsetInVBTable = + VTableContext.getVBTableIndex(MostDerivedClass, Class.VirtualRoot)*4; + VBPtrOffset = MostDerivedLayout.getVBPtrOffset().getQuantity(); + } + + // Turn our record back into a pointer if the exception object is a + // pointer. + QualType RTTITy = QualType(Class.RD->getTypeForDecl(), 0); + if (IsPointer) + RTTITy = Context.getPointerType(RTTITy); + CatchableTypes.insert(getCatchableType(RTTITy, Class.OffsetInVBase, + VBPtrOffset, OffsetInVBTable)); + } + } + + // C++14 [except.handle]p3: + // A handler is a match for an exception object of type E if + // - The handler is of type cv T or cv T& and E and T are the same type + // (ignoring the top-level cv-qualifiers) + CatchableTypes.insert(getCatchableType(T)); + + // C++14 [except.handle]p3: + // A handler is a match for an exception object of type E if + // - the handler is of type cv T or const T& where T is a pointer type and + // E is a pointer type that can be converted to T by [...] + // - a standard pointer conversion (4.10) not involving conversions to + // pointers to private or protected or ambiguous classes + // + // C++14 [conv.ptr]p2: + // A prvalue of type "pointer to cv T," where T is an object type, can be + // converted to a prvalue of type "pointer to cv void". + if (IsPointer && T->getPointeeType()->isObjectType()) + CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy)); + + // C++14 [except.handle]p3: + // A handler is a match for an exception object of type E if [...] + // - the handler is of type cv T or const T& where T is a pointer or + // pointer to member type and E is std::nullptr_t. + // + // We cannot possibly list all possible pointer types here, making this + // implementation incompatible with the standard. However, MSVC includes an + // entry for pointer-to-void in this case. Let's do the same. + if (T->isNullPtrType()) + CatchableTypes.insert(getCatchableType(getContext().VoidPtrTy)); + + uint32_t NumEntries = CatchableTypes.size(); + llvm::Type *CTType = + getImageRelativeType(getCatchableTypeType()->getPointerTo()); + llvm::ArrayType *AT = llvm::ArrayType::get(CTType, NumEntries); + llvm::StructType *CTAType = getCatchableTypeArrayType(NumEntries); + llvm::Constant *Fields[] = { + llvm::ConstantInt::get(CGM.IntTy, NumEntries), // NumEntries + llvm::ConstantArray::get( + AT, llvm::makeArrayRef(CatchableTypes.begin(), + CatchableTypes.end())) // CatchableTypes + }; + SmallString<256> MangledName; + { + llvm::raw_svector_ostream Out(MangledName); + getMangleContext().mangleCXXCatchableTypeArray(T, NumEntries, Out); + } + CTA = new llvm::GlobalVariable( + CGM.getModule(), CTAType, /*Constant=*/true, getLinkageForRTTI(T), + llvm::ConstantStruct::get(CTAType, Fields), StringRef(MangledName)); + CTA->setUnnamedAddr(true); + CTA->setSection(".xdata"); + if (CTA->isWeakForLinker()) + CTA->setComdat(CGM.getModule().getOrInsertComdat(CTA->getName())); + return CTA; +} + +llvm::GlobalVariable *MicrosoftCXXABI::getThrowInfo(QualType T) { + bool IsConst, IsVolatile; + T = decomposeTypeForEH(getContext(), T, IsConst, IsVolatile); + + // The CatchableTypeArray enumerates the various (CV-unqualified) types that + // the exception object may be caught as. + llvm::GlobalVariable *CTA = getCatchableTypeArray(T); + // The first field in a CatchableTypeArray is the number of CatchableTypes. + // This is used as a component of the mangled name which means that we need to + // know what it is in order to see if we have previously generated the + // ThrowInfo. + uint32_t NumEntries = + cast<llvm::ConstantInt>(CTA->getInitializer()->getAggregateElement(0U)) + ->getLimitedValue(); + + SmallString<256> MangledName; + { + llvm::raw_svector_ostream Out(MangledName); + getMangleContext().mangleCXXThrowInfo(T, IsConst, IsVolatile, NumEntries, + Out); + } + + // Reuse a previously generated ThrowInfo if we have generated an appropriate + // one before. + if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName)) + return GV; + + // The RTTI TypeDescriptor uses an unqualified type but catch clauses must + // be at least as CV qualified. Encode this requirement into the Flags + // bitfield. + uint32_t Flags = 0; + if (IsConst) + Flags |= 1; + if (IsVolatile) + Flags |= 2; + + // The cleanup-function (a destructor) must be called when the exception + // object's lifetime ends. + llvm::Constant *CleanupFn = llvm::Constant::getNullValue(CGM.Int8PtrTy); + if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl()) + if (CXXDestructorDecl *DtorD = RD->getDestructor()) + if (!DtorD->isTrivial()) + CleanupFn = llvm::ConstantExpr::getBitCast( + CGM.getAddrOfCXXStructor(DtorD, StructorType::Complete), + CGM.Int8PtrTy); + // This is unused as far as we can tell, initialize it to null. + llvm::Constant *ForwardCompat = + getImageRelativeConstant(llvm::Constant::getNullValue(CGM.Int8PtrTy)); + llvm::Constant *PointerToCatchableTypes = getImageRelativeConstant( + llvm::ConstantExpr::getBitCast(CTA, CGM.Int8PtrTy)); + llvm::StructType *TIType = getThrowInfoType(); + llvm::Constant *Fields[] = { + llvm::ConstantInt::get(CGM.IntTy, Flags), // Flags + getImageRelativeConstant(CleanupFn), // CleanupFn + ForwardCompat, // ForwardCompat + PointerToCatchableTypes // CatchableTypeArray + }; + auto *GV = new llvm::GlobalVariable( + CGM.getModule(), TIType, /*Constant=*/true, getLinkageForRTTI(T), + llvm::ConstantStruct::get(TIType, Fields), StringRef(MangledName)); + GV->setUnnamedAddr(true); + GV->setSection(".xdata"); + if (GV->isWeakForLinker()) + GV->setComdat(CGM.getModule().getOrInsertComdat(GV->getName())); + return GV; +} + +void MicrosoftCXXABI::emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) { + const Expr *SubExpr = E->getSubExpr(); + QualType ThrowType = SubExpr->getType(); + // The exception object lives on the stack and it's address is passed to the + // runtime function. + llvm::AllocaInst *AI = CGF.CreateMemTemp(ThrowType); + CGF.EmitAnyExprToMem(SubExpr, AI, ThrowType.getQualifiers(), + /*IsInit=*/true); + + // The so-called ThrowInfo is used to describe how the exception object may be + // caught. + llvm::GlobalVariable *TI = getThrowInfo(ThrowType); + + // Call into the runtime to throw the exception. + llvm::Value *Args[] = {CGF.Builder.CreateBitCast(AI, CGM.Int8PtrTy), TI}; + CGF.EmitNoreturnRuntimeCallOrInvoke(getThrowFn(), Args); +} |