| //===------- ItaniumCXXABI.cpp - Emit LLVM Code from ASTs for a Module ----===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This provides C++ code generation targeting the Itanium C++ ABI. The class |
| // in this file generates structures that follow the Itanium C++ ABI, which is |
| // documented at: |
| // http://www.codesourcery.com/public/cxx-abi/abi.html |
| // http://www.codesourcery.com/public/cxx-abi/abi-eh.html |
| // |
| // It also supports the closely-related ARM ABI, documented at: |
| // http://infocenter.arm.com/help/topic/com.arm.doc.ihi0041c/IHI0041C_cppabi.pdf |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "CGCXXABI.h" |
| #include "CGCleanup.h" |
| #include "CGRecordLayout.h" |
| #include "CGVTables.h" |
| #include "CodeGenFunction.h" |
| #include "CodeGenModule.h" |
| #include "TargetInfo.h" |
| #include "clang/AST/Attr.h" |
| #include "clang/AST/Mangle.h" |
| #include "clang/AST/StmtCXX.h" |
| #include "clang/AST/Type.h" |
| #include "clang/CodeGen/ConstantInitBuilder.h" |
| #include "llvm/IR/DataLayout.h" |
| #include "llvm/IR/GlobalValue.h" |
| #include "llvm/IR/Instructions.h" |
| #include "llvm/IR/Intrinsics.h" |
| #include "llvm/IR/Value.h" |
| #include "llvm/Support/ScopedPrinter.h" |
| |
| using namespace clang; |
| using namespace CodeGen; |
| |
| namespace { |
| class ItaniumCXXABI : public CodeGen::CGCXXABI { |
| /// VTables - All the vtables which have been defined. |
| llvm::DenseMap<const CXXRecordDecl *, llvm::GlobalVariable *> VTables; |
| |
| /// All the thread wrapper functions that have been used. |
| llvm::SmallVector<std::pair<const VarDecl *, llvm::Function *>, 8> |
| ThreadWrappers; |
| |
| protected: |
| bool UseARMMethodPtrABI; |
| bool UseARMGuardVarABI; |
| bool Use32BitVTableOffsetABI; |
| |
| ItaniumMangleContext &getMangleContext() { |
| return cast<ItaniumMangleContext>(CodeGen::CGCXXABI::getMangleContext()); |
| } |
| |
| public: |
| ItaniumCXXABI(CodeGen::CodeGenModule &CGM, |
| bool UseARMMethodPtrABI = false, |
| bool UseARMGuardVarABI = false) : |
| CGCXXABI(CGM), UseARMMethodPtrABI(UseARMMethodPtrABI), |
| UseARMGuardVarABI(UseARMGuardVarABI), |
| Use32BitVTableOffsetABI(false) { } |
| |
| bool classifyReturnType(CGFunctionInfo &FI) const override; |
| |
| RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const override { |
| // If C++ prohibits us from making a copy, pass by address. |
| if (!RD->canPassInRegisters()) |
| return RAA_Indirect; |
| return RAA_Default; |
| } |
| |
| bool isThisCompleteObject(GlobalDecl GD) const override { |
| // The Itanium ABI has separate complete-object vs. base-object |
| // variants of both constructors and destructors. |
| if (isa<CXXDestructorDecl>(GD.getDecl())) { |
| switch (GD.getDtorType()) { |
| case Dtor_Complete: |
| case Dtor_Deleting: |
| return true; |
| |
| case Dtor_Base: |
| return false; |
| |
| case Dtor_Comdat: |
| llvm_unreachable("emitting dtor comdat as function?"); |
| } |
| llvm_unreachable("bad dtor kind"); |
| } |
| if (isa<CXXConstructorDecl>(GD.getDecl())) { |
| switch (GD.getCtorType()) { |
| case Ctor_Complete: |
| return true; |
| |
| case Ctor_Base: |
| return false; |
| |
| case Ctor_CopyingClosure: |
| case Ctor_DefaultClosure: |
| llvm_unreachable("closure ctors in Itanium ABI?"); |
| |
| case Ctor_Comdat: |
| llvm_unreachable("emitting ctor comdat as function?"); |
| } |
| llvm_unreachable("bad dtor kind"); |
| } |
| |
| // No other kinds. |
| return false; |
| } |
| |
| bool isZeroInitializable(const MemberPointerType *MPT) override; |
| |
| llvm::Type *ConvertMemberPointerType(const MemberPointerType *MPT) override; |
| |
| CGCallee |
| EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, |
| const Expr *E, |
| Address This, |
| llvm::Value *&ThisPtrForCall, |
| llvm::Value *MemFnPtr, |
| const MemberPointerType *MPT) override; |
| |
| llvm::Value * |
| EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E, |
| Address Base, |
| llvm::Value *MemPtr, |
| const MemberPointerType *MPT) override; |
| |
| llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF, |
| const CastExpr *E, |
| llvm::Value *Src) override; |
| llvm::Constant *EmitMemberPointerConversion(const CastExpr *E, |
| llvm::Constant *Src) override; |
| |
| llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT) override; |
| |
| llvm::Constant *EmitMemberFunctionPointer(const CXXMethodDecl *MD) override; |
| llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT, |
| CharUnits offset) override; |
| llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT) override; |
| llvm::Constant *BuildMemberPointer(const CXXMethodDecl *MD, |
| CharUnits ThisAdjustment); |
| |
| llvm::Value *EmitMemberPointerComparison(CodeGenFunction &CGF, |
| llvm::Value *L, llvm::Value *R, |
| const MemberPointerType *MPT, |
| bool Inequality) override; |
| |
| llvm::Value *EmitMemberPointerIsNotNull(CodeGenFunction &CGF, |
| llvm::Value *Addr, |
| const MemberPointerType *MPT) override; |
| |
| void emitVirtualObjectDelete(CodeGenFunction &CGF, const CXXDeleteExpr *DE, |
| Address Ptr, QualType ElementType, |
| const CXXDestructorDecl *Dtor) override; |
| |
| void emitRethrow(CodeGenFunction &CGF, bool isNoReturn) override; |
| void emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) override; |
| |
| void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) override; |
| |
| llvm::CallInst * |
| emitTerminateForUnexpectedException(CodeGenFunction &CGF, |
| llvm::Value *Exn) override; |
| |
| void EmitFundamentalRTTIDescriptors(const CXXRecordDecl *RD); |
| llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) override; |
| CatchTypeInfo |
| getAddrOfCXXCatchHandlerType(QualType Ty, |
| QualType CatchHandlerType) override { |
| return CatchTypeInfo{getAddrOfRTTIDescriptor(Ty), 0}; |
| } |
| |
| bool shouldTypeidBeNullChecked(bool IsDeref, QualType SrcRecordTy) override; |
| void EmitBadTypeidCall(CodeGenFunction &CGF) override; |
| llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy, |
| Address ThisPtr, |
| llvm::Type *StdTypeInfoPtrTy) override; |
| |
| bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr, |
| QualType SrcRecordTy) override; |
| |
| llvm::Value *EmitDynamicCastCall(CodeGenFunction &CGF, Address Value, |
| QualType SrcRecordTy, QualType DestTy, |
| QualType DestRecordTy, |
| llvm::BasicBlock *CastEnd) override; |
| |
| llvm::Value *EmitDynamicCastToVoid(CodeGenFunction &CGF, Address Value, |
| QualType SrcRecordTy, |
| QualType DestTy) override; |
| |
| bool EmitBadCastCall(CodeGenFunction &CGF) override; |
| |
| llvm::Value * |
| GetVirtualBaseClassOffset(CodeGenFunction &CGF, Address This, |
| const CXXRecordDecl *ClassDecl, |
| const CXXRecordDecl *BaseClassDecl) override; |
| |
| void EmitCXXConstructors(const CXXConstructorDecl *D) override; |
| |
| AddedStructorArgCounts |
| buildStructorSignature(GlobalDecl GD, |
| SmallVectorImpl<CanQualType> &ArgTys) override; |
| |
| bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor, |
| CXXDtorType DT) const override { |
| // Itanium does not emit any destructor variant as an inline thunk. |
| // Delegating may occur as an optimization, but all variants are either |
| // emitted with external linkage or as linkonce if they are inline and used. |
| return false; |
| } |
| |
| void EmitCXXDestructors(const CXXDestructorDecl *D) override; |
| |
| void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy, |
| FunctionArgList &Params) override; |
| |
| void EmitInstanceFunctionProlog(CodeGenFunction &CGF) override; |
| |
| AddedStructorArgs getImplicitConstructorArgs(CodeGenFunction &CGF, |
| const CXXConstructorDecl *D, |
| CXXCtorType Type, |
| bool ForVirtualBase, |
| bool Delegating) override; |
| |
| llvm::Value *getCXXDestructorImplicitParam(CodeGenFunction &CGF, |
| const CXXDestructorDecl *DD, |
| CXXDtorType Type, |
| bool ForVirtualBase, |
| bool Delegating) override; |
| |
| void EmitDestructorCall(CodeGenFunction &CGF, const CXXDestructorDecl *DD, |
| CXXDtorType Type, bool ForVirtualBase, |
| bool Delegating, Address This, |
| QualType ThisTy) override; |
| |
| void emitVTableDefinitions(CodeGenVTables &CGVT, |
| const CXXRecordDecl *RD) override; |
| |
| bool isVirtualOffsetNeededForVTableField(CodeGenFunction &CGF, |
| CodeGenFunction::VPtr Vptr) override; |
| |
| bool doStructorsInitializeVPtrs(const CXXRecordDecl *VTableClass) override { |
| return true; |
| } |
| |
| llvm::Constant * |
| getVTableAddressPoint(BaseSubobject Base, |
| const CXXRecordDecl *VTableClass) override; |
| |
| llvm::Value *getVTableAddressPointInStructor( |
| CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, |
| BaseSubobject Base, const CXXRecordDecl *NearestVBase) override; |
| |
| llvm::Value *getVTableAddressPointInStructorWithVTT( |
| CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, |
| BaseSubobject Base, const CXXRecordDecl *NearestVBase); |
| |
| llvm::Constant * |
| getVTableAddressPointForConstExpr(BaseSubobject Base, |
| const CXXRecordDecl *VTableClass) override; |
| |
| llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD, |
| CharUnits VPtrOffset) override; |
| |
| CGCallee getVirtualFunctionPointer(CodeGenFunction &CGF, GlobalDecl GD, |
| Address This, llvm::Type *Ty, |
| SourceLocation Loc) override; |
| |
| llvm::Value *EmitVirtualDestructorCall(CodeGenFunction &CGF, |
| const CXXDestructorDecl *Dtor, |
| CXXDtorType DtorType, Address This, |
| DeleteOrMemberCallExpr E) override; |
| |
| void emitVirtualInheritanceTables(const CXXRecordDecl *RD) override; |
| |
| bool canSpeculativelyEmitVTable(const CXXRecordDecl *RD) const override; |
| bool canSpeculativelyEmitVTableAsBaseClass(const CXXRecordDecl *RD) const; |
| |
| void setThunkLinkage(llvm::Function *Thunk, bool ForVTable, GlobalDecl GD, |
| bool ReturnAdjustment) override { |
| // Allow inlining of thunks by emitting them with available_externally |
| // linkage together with vtables when needed. |
| if (ForVTable && !Thunk->hasLocalLinkage()) |
| Thunk->setLinkage(llvm::GlobalValue::AvailableExternallyLinkage); |
| CGM.setGVProperties(Thunk, GD); |
| } |
| |
| bool exportThunk() override { return true; } |
| |
| llvm::Value *performThisAdjustment(CodeGenFunction &CGF, Address This, |
| const ThisAdjustment &TA) override; |
| |
| llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, Address Ret, |
| const ReturnAdjustment &RA) override; |
| |
| size_t getSrcArgforCopyCtor(const CXXConstructorDecl *, |
| FunctionArgList &Args) const override { |
| assert(!Args.empty() && "expected the arglist to not be empty!"); |
| return Args.size() - 1; |
| } |
| |
| StringRef GetPureVirtualCallName() override { return "__cxa_pure_virtual"; } |
| StringRef GetDeletedVirtualCallName() override |
| { return "__cxa_deleted_virtual"; } |
| |
| CharUnits getArrayCookieSizeImpl(QualType elementType) override; |
| Address InitializeArrayCookie(CodeGenFunction &CGF, |
| Address NewPtr, |
| llvm::Value *NumElements, |
| const CXXNewExpr *expr, |
| QualType ElementType) override; |
| llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF, |
| Address allocPtr, |
| CharUnits cookieSize) override; |
| |
| void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D, |
| llvm::GlobalVariable *DeclPtr, |
| bool PerformInit) override; |
| void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D, |
| llvm::FunctionCallee dtor, |
| llvm::Constant *addr) override; |
| |
| llvm::Function *getOrCreateThreadLocalWrapper(const VarDecl *VD, |
| llvm::Value *Val); |
| void EmitThreadLocalInitFuncs( |
| CodeGenModule &CGM, |
| ArrayRef<const VarDecl *> CXXThreadLocals, |
| ArrayRef<llvm::Function *> CXXThreadLocalInits, |
| ArrayRef<const VarDecl *> CXXThreadLocalInitVars) override; |
| |
| /// Determine whether we will definitely emit this variable with a constant |
| /// initializer, either because the language semantics demand it or because |
| /// we know that the initializer is a constant. |
| bool isEmittedWithConstantInitializer(const VarDecl *VD) const { |
| VD = VD->getMostRecentDecl(); |
| if (VD->hasAttr<ConstInitAttr>()) |
| return true; |
| |
| // All later checks examine the initializer specified on the variable. If |
| // the variable is weak, such examination would not be correct. |
| if (VD->isWeak() || VD->hasAttr<SelectAnyAttr>()) |
| return false; |
| |
| const VarDecl *InitDecl = VD->getInitializingDeclaration(); |
| if (!InitDecl) |
| return false; |
| |
| // If there's no initializer to run, this is constant initialization. |
| if (!InitDecl->hasInit()) |
| return true; |
| |
| // If we have the only definition, we don't need a thread wrapper if we |
| // will emit the value as a constant. |
| if (isUniqueGVALinkage(getContext().GetGVALinkageForVariable(VD))) |
| return !VD->needsDestruction(getContext()) && InitDecl->evaluateValue(); |
| |
| // Otherwise, we need a thread wrapper unless we know that every |
| // translation unit will emit the value as a constant. We rely on |
| // ICE-ness not varying between translation units, which isn't actually |
| // guaranteed by the standard but is necessary for sanity. |
| return InitDecl->isInitKnownICE() && InitDecl->isInitICE(); |
| } |
| |
| bool usesThreadWrapperFunction(const VarDecl *VD) const override { |
| return !isEmittedWithConstantInitializer(VD) || |
| VD->needsDestruction(getContext()); |
| } |
| LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, const VarDecl *VD, |
| QualType LValType) override; |
| |
| bool NeedsVTTParameter(GlobalDecl GD) override; |
| |
| /**************************** RTTI Uniqueness ******************************/ |
| |
| protected: |
| /// Returns true if the ABI requires RTTI type_info objects to be unique |
| /// across a program. |
| virtual bool shouldRTTIBeUnique() const { return true; } |
| |
| public: |
| /// What sort of unique-RTTI behavior should we use? |
| enum RTTIUniquenessKind { |
| /// We are guaranteeing, or need to guarantee, that the RTTI string |
| /// is unique. |
| RUK_Unique, |
| |
| /// We are not guaranteeing uniqueness for the RTTI string, so we |
| /// can demote to hidden visibility but must use string comparisons. |
| RUK_NonUniqueHidden, |
| |
| /// We are not guaranteeing uniqueness for the RTTI string, so we |
| /// have to use string comparisons, but we also have to emit it with |
| /// non-hidden visibility. |
| RUK_NonUniqueVisible |
| }; |
| |
| /// Return the required visibility status for the given type and linkage in |
| /// the current ABI. |
| RTTIUniquenessKind |
| classifyRTTIUniqueness(QualType CanTy, |
| llvm::GlobalValue::LinkageTypes Linkage) const; |
| friend class ItaniumRTTIBuilder; |
| |
| void emitCXXStructor(GlobalDecl GD) override; |
| |
| std::pair<llvm::Value *, const CXXRecordDecl *> |
| LoadVTablePtr(CodeGenFunction &CGF, Address This, |
| const CXXRecordDecl *RD) override; |
| |
| private: |
| bool hasAnyUnusedVirtualInlineFunction(const CXXRecordDecl *RD) const { |
| const auto &VtableLayout = |
| CGM.getItaniumVTableContext().getVTableLayout(RD); |
| |
| for (const auto &VtableComponent : VtableLayout.vtable_components()) { |
| // Skip empty slot. |
| if (!VtableComponent.isUsedFunctionPointerKind()) |
| continue; |
| |
| const CXXMethodDecl *Method = VtableComponent.getFunctionDecl(); |
| if (!Method->getCanonicalDecl()->isInlined()) |
| continue; |
| |
| StringRef Name = CGM.getMangledName(VtableComponent.getGlobalDecl()); |
| auto *Entry = CGM.GetGlobalValue(Name); |
| // This checks if virtual inline function has already been emitted. |
| // Note that it is possible that this inline function would be emitted |
| // after trying to emit vtable speculatively. Because of this we do |
| // an extra pass after emitting all deferred vtables to find and emit |
| // these vtables opportunistically. |
| if (!Entry || Entry->isDeclaration()) |
| return true; |
| } |
| return false; |
| } |
| |
| bool isVTableHidden(const CXXRecordDecl *RD) const { |
| const auto &VtableLayout = |
| CGM.getItaniumVTableContext().getVTableLayout(RD); |
| |
| for (const auto &VtableComponent : VtableLayout.vtable_components()) { |
| if (VtableComponent.isRTTIKind()) { |
| const CXXRecordDecl *RTTIDecl = VtableComponent.getRTTIDecl(); |
| if (RTTIDecl->getVisibility() == Visibility::HiddenVisibility) |
| return true; |
| } else if (VtableComponent.isUsedFunctionPointerKind()) { |
| const CXXMethodDecl *Method = VtableComponent.getFunctionDecl(); |
| if (Method->getVisibility() == Visibility::HiddenVisibility && |
| !Method->isDefined()) |
| return true; |
| } |
| } |
| return false; |
| } |
| }; |
| |
| class ARMCXXABI : public ItaniumCXXABI { |
| public: |
| ARMCXXABI(CodeGen::CodeGenModule &CGM) : |
| ItaniumCXXABI(CGM, /*UseARMMethodPtrABI=*/true, |
| /*UseARMGuardVarABI=*/true) {} |
| |
| bool HasThisReturn(GlobalDecl GD) const override { |
| return (isa<CXXConstructorDecl>(GD.getDecl()) || ( |
| isa<CXXDestructorDecl>(GD.getDecl()) && |
| GD.getDtorType() != Dtor_Deleting)); |
| } |
| |
| void EmitReturnFromThunk(CodeGenFunction &CGF, RValue RV, |
| QualType ResTy) override; |
| |
| CharUnits getArrayCookieSizeImpl(QualType elementType) override; |
| Address InitializeArrayCookie(CodeGenFunction &CGF, |
| Address NewPtr, |
| llvm::Value *NumElements, |
| const CXXNewExpr *expr, |
| QualType ElementType) override; |
| llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF, Address allocPtr, |
| CharUnits cookieSize) override; |
| }; |
| |
| class iOS64CXXABI : public ARMCXXABI { |
| public: |
| iOS64CXXABI(CodeGen::CodeGenModule &CGM) : ARMCXXABI(CGM) { |
| Use32BitVTableOffsetABI = true; |
| } |
| |
| // ARM64 libraries are prepared for non-unique RTTI. |
| bool shouldRTTIBeUnique() const override { return false; } |
| }; |
| |
| class FuchsiaCXXABI final : public ItaniumCXXABI { |
| public: |
| explicit FuchsiaCXXABI(CodeGen::CodeGenModule &CGM) |
| : ItaniumCXXABI(CGM) {} |
| |
| private: |
| bool HasThisReturn(GlobalDecl GD) const override { |
| return isa<CXXConstructorDecl>(GD.getDecl()) || |
| (isa<CXXDestructorDecl>(GD.getDecl()) && |
| GD.getDtorType() != Dtor_Deleting); |
| } |
| }; |
| |
| class WebAssemblyCXXABI final : public ItaniumCXXABI { |
| public: |
| explicit WebAssemblyCXXABI(CodeGen::CodeGenModule &CGM) |
| : ItaniumCXXABI(CGM, /*UseARMMethodPtrABI=*/true, |
| /*UseARMGuardVarABI=*/true) {} |
| void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) override; |
| |
| private: |
| bool HasThisReturn(GlobalDecl GD) const override { |
| return isa<CXXConstructorDecl>(GD.getDecl()) || |
| (isa<CXXDestructorDecl>(GD.getDecl()) && |
| GD.getDtorType() != Dtor_Deleting); |
| } |
| bool canCallMismatchedFunctionType() const override { return false; } |
| }; |
| |
| class XLCXXABI final : public ItaniumCXXABI { |
| public: |
| explicit XLCXXABI(CodeGen::CodeGenModule &CGM) |
| : ItaniumCXXABI(CGM) {} |
| |
| void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D, |
| llvm::FunctionCallee dtor, |
| llvm::Constant *addr) override; |
| |
| bool useSinitAndSterm() const override { return true; } |
| |
| private: |
| void emitCXXStermFinalizer(const VarDecl &D, llvm::Function *dtorStub, |
| llvm::Constant *addr); |
| }; |
| } |
| |
| CodeGen::CGCXXABI *CodeGen::CreateItaniumCXXABI(CodeGenModule &CGM) { |
| switch (CGM.getTarget().getCXXABI().getKind()) { |
| // For IR-generation purposes, there's no significant difference |
| // between the ARM and iOS ABIs. |
| case TargetCXXABI::GenericARM: |
| case TargetCXXABI::iOS: |
| case TargetCXXABI::WatchOS: |
| return new ARMCXXABI(CGM); |
| |
| case TargetCXXABI::iOS64: |
| return new iOS64CXXABI(CGM); |
| |
| case TargetCXXABI::Fuchsia: |
| return new FuchsiaCXXABI(CGM); |
| |
| // Note that AArch64 uses the generic ItaniumCXXABI class since it doesn't |
| // include the other 32-bit ARM oddities: constructor/destructor return values |
| // and array cookies. |
| case TargetCXXABI::GenericAArch64: |
| return new ItaniumCXXABI(CGM, /*UseARMMethodPtrABI=*/true, |
| /*UseARMGuardVarABI=*/true); |
| |
| case TargetCXXABI::GenericMIPS: |
| return new ItaniumCXXABI(CGM, /*UseARMMethodPtrABI=*/true); |
| |
| case TargetCXXABI::WebAssembly: |
| return new WebAssemblyCXXABI(CGM); |
| |
| case TargetCXXABI::XL: |
| return new XLCXXABI(CGM); |
| |
| case TargetCXXABI::GenericItanium: |
| if (CGM.getContext().getTargetInfo().getTriple().getArch() |
| == llvm::Triple::le32) { |
| // For PNaCl, use ARM-style method pointers so that PNaCl code |
| // does not assume anything about the alignment of function |
| // pointers. |
| return new ItaniumCXXABI(CGM, /*UseARMMethodPtrABI=*/true); |
| } |
| return new ItaniumCXXABI(CGM); |
| |
| case TargetCXXABI::Microsoft: |
| llvm_unreachable("Microsoft ABI is not Itanium-based"); |
| } |
| llvm_unreachable("bad ABI kind"); |
| } |
| |
| llvm::Type * |
| ItaniumCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) { |
| if (MPT->isMemberDataPointer()) |
| return CGM.PtrDiffTy; |
| return llvm::StructType::get(CGM.PtrDiffTy, CGM.PtrDiffTy); |
| } |
| |
| /// In the Itanium and ARM ABIs, method pointers have the form: |
| /// struct { ptrdiff_t ptr; ptrdiff_t adj; } memptr; |
| /// |
| /// In the Itanium ABI: |
| /// - method pointers are virtual if (memptr.ptr & 1) is nonzero |
| /// - the this-adjustment is (memptr.adj) |
| /// - the virtual offset is (memptr.ptr - 1) |
| /// |
| /// In the ARM ABI: |
| /// - method pointers are virtual if (memptr.adj & 1) is nonzero |
| /// - the this-adjustment is (memptr.adj >> 1) |
| /// - the virtual offset is (memptr.ptr) |
| /// ARM uses 'adj' for the virtual flag because Thumb functions |
| /// may be only single-byte aligned. |
| /// |
| /// If the member is virtual, the adjusted 'this' pointer points |
| /// to a vtable pointer from which the virtual offset is applied. |
| /// |
| /// If the member is non-virtual, memptr.ptr is the address of |
| /// the function to call. |
| CGCallee ItaniumCXXABI::EmitLoadOfMemberFunctionPointer( |
| CodeGenFunction &CGF, const Expr *E, Address ThisAddr, |
| llvm::Value *&ThisPtrForCall, |
| llvm::Value *MemFnPtr, const MemberPointerType *MPT) { |
| CGBuilderTy &Builder = CGF.Builder; |
| |
| const FunctionProtoType *FPT = |
| MPT->getPointeeType()->getAs<FunctionProtoType>(); |
| auto *RD = |
| cast<CXXRecordDecl>(MPT->getClass()->castAs<RecordType>()->getDecl()); |
| |
| llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType( |
| CGM.getTypes().arrangeCXXMethodType(RD, FPT, /*FD=*/nullptr)); |
| |
| llvm::Constant *ptrdiff_1 = llvm::ConstantInt::get(CGM.PtrDiffTy, 1); |
| |
| llvm::BasicBlock *FnVirtual = CGF.createBasicBlock("memptr.virtual"); |
| llvm::BasicBlock *FnNonVirtual = CGF.createBasicBlock("memptr.nonvirtual"); |
| llvm::BasicBlock *FnEnd = CGF.createBasicBlock("memptr.end"); |
| |
| // Extract memptr.adj, which is in the second field. |
| llvm::Value *RawAdj = Builder.CreateExtractValue(MemFnPtr, 1, "memptr.adj"); |
| |
| // Compute the true adjustment. |
| llvm::Value *Adj = RawAdj; |
| if (UseARMMethodPtrABI) |
| Adj = Builder.CreateAShr(Adj, ptrdiff_1, "memptr.adj.shifted"); |
| |
| // Apply the adjustment and cast back to the original struct type |
| // for consistency. |
| llvm::Value *This = ThisAddr.getPointer(); |
| llvm::Value *Ptr = Builder.CreateBitCast(This, Builder.getInt8PtrTy()); |
| Ptr = Builder.CreateInBoundsGEP(Ptr, Adj); |
| This = Builder.CreateBitCast(Ptr, This->getType(), "this.adjusted"); |
| ThisPtrForCall = This; |
| |
| // Load the function pointer. |
| llvm::Value *FnAsInt = Builder.CreateExtractValue(MemFnPtr, 0, "memptr.ptr"); |
| |
| // If the LSB in the function pointer is 1, the function pointer points to |
| // a virtual function. |
| llvm::Value *IsVirtual; |
| if (UseARMMethodPtrABI) |
| IsVirtual = Builder.CreateAnd(RawAdj, ptrdiff_1); |
| else |
| IsVirtual = Builder.CreateAnd(FnAsInt, ptrdiff_1); |
| IsVirtual = Builder.CreateIsNotNull(IsVirtual, "memptr.isvirtual"); |
| Builder.CreateCondBr(IsVirtual, FnVirtual, FnNonVirtual); |
| |
| // In the virtual path, the adjustment left 'This' pointing to the |
| // vtable of the correct base subobject. The "function pointer" is an |
| // offset within the vtable (+1 for the virtual flag on non-ARM). |
| CGF.EmitBlock(FnVirtual); |
| |
| // Cast the adjusted this to a pointer to vtable pointer and load. |
| llvm::Type *VTableTy = Builder.getInt8PtrTy(); |
| CharUnits VTablePtrAlign = |
| CGF.CGM.getDynamicOffsetAlignment(ThisAddr.getAlignment(), RD, |
| CGF.getPointerAlign()); |
| llvm::Value *VTable = |
| CGF.GetVTablePtr(Address(This, VTablePtrAlign), VTableTy, RD); |
| |
| // Apply the offset. |
| // On ARM64, to reserve extra space in virtual member function pointers, |
| // we only pay attention to the low 32 bits of the offset. |
| llvm::Value *VTableOffset = FnAsInt; |
| if (!UseARMMethodPtrABI) |
| VTableOffset = Builder.CreateSub(VTableOffset, ptrdiff_1); |
| if (Use32BitVTableOffsetABI) { |
| VTableOffset = Builder.CreateTrunc(VTableOffset, CGF.Int32Ty); |
| VTableOffset = Builder.CreateZExt(VTableOffset, CGM.PtrDiffTy); |
| } |
| |
| // Check the address of the function pointer if CFI on member function |
| // pointers is enabled. |
| llvm::Constant *CheckSourceLocation; |
| llvm::Constant *CheckTypeDesc; |
| bool ShouldEmitCFICheck = CGF.SanOpts.has(SanitizerKind::CFIMFCall) && |
| CGM.HasHiddenLTOVisibility(RD); |
| bool ShouldEmitVFEInfo = CGM.getCodeGenOpts().VirtualFunctionElimination && |
| CGM.HasHiddenLTOVisibility(RD); |
| bool ShouldEmitWPDInfo = |
| CGM.getCodeGenOpts().WholeProgramVTables && |
| // Don't insert type tests if we are forcing public std visibility. |
| !CGM.HasLTOVisibilityPublicStd(RD); |
| llvm::Value *VirtualFn = nullptr; |
| |
| { |
| CodeGenFunction::SanitizerScope SanScope(&CGF); |
| llvm::Value *TypeId = nullptr; |
| llvm::Value *CheckResult = nullptr; |
| |
| if (ShouldEmitCFICheck || ShouldEmitVFEInfo || ShouldEmitWPDInfo) { |
| // If doing CFI, VFE or WPD, we will need the metadata node to check |
| // against. |
| llvm::Metadata *MD = |
| CGM.CreateMetadataIdentifierForVirtualMemPtrType(QualType(MPT, 0)); |
| TypeId = llvm::MetadataAsValue::get(CGF.getLLVMContext(), MD); |
| } |
| |
| if (ShouldEmitVFEInfo) { |
| llvm::Value *VFPAddr = Builder.CreateGEP(VTable, VTableOffset); |
| |
| // If doing VFE, load from the vtable with a type.checked.load intrinsic |
| // call. Note that we use the GEP to calculate the address to load from |
| // and pass 0 as the offset to the intrinsic. This is because every |
| // vtable slot of the correct type is marked with matching metadata, and |
| // we know that the load must be from one of these slots. |
| llvm::Value *CheckedLoad = Builder.CreateCall( |
| CGM.getIntrinsic(llvm::Intrinsic::type_checked_load), |
| {VFPAddr, llvm::ConstantInt::get(CGM.Int32Ty, 0), TypeId}); |
| CheckResult = Builder.CreateExtractValue(CheckedLoad, 1); |
| VirtualFn = Builder.CreateExtractValue(CheckedLoad, 0); |
| VirtualFn = Builder.CreateBitCast(VirtualFn, FTy->getPointerTo(), |
| "memptr.virtualfn"); |
| } else { |
| // When not doing VFE, emit a normal load, as it allows more |
| // optimisations than type.checked.load. |
| if (ShouldEmitCFICheck || ShouldEmitWPDInfo) { |
| llvm::Value *VFPAddr = Builder.CreateGEP(VTable, VTableOffset); |
| CheckResult = Builder.CreateCall( |
| CGM.getIntrinsic(llvm::Intrinsic::type_test), |
| {Builder.CreateBitCast(VFPAddr, CGF.Int8PtrTy), TypeId}); |
| } |
| |
| if (CGM.getItaniumVTableContext().isRelativeLayout()) { |
| VirtualFn = CGF.Builder.CreateCall( |
| CGM.getIntrinsic(llvm::Intrinsic::load_relative, |
| {VTableOffset->getType()}), |
| {VTable, VTableOffset}); |
| VirtualFn = CGF.Builder.CreateBitCast(VirtualFn, FTy->getPointerTo()); |
| } else { |
| llvm::Value *VFPAddr = CGF.Builder.CreateGEP(VTable, VTableOffset); |
| VFPAddr = CGF.Builder.CreateBitCast( |
| VFPAddr, FTy->getPointerTo()->getPointerTo()); |
| VirtualFn = CGF.Builder.CreateAlignedLoad( |
| VFPAddr, CGF.getPointerAlign(), "memptr.virtualfn"); |
| } |
| } |
| assert(VirtualFn && "Virtual fuction pointer not created!"); |
| assert((!ShouldEmitCFICheck || !ShouldEmitVFEInfo || !ShouldEmitWPDInfo || |
| CheckResult) && |
| "Check result required but not created!"); |
| |
| if (ShouldEmitCFICheck) { |
| // If doing CFI, emit the check. |
| CheckSourceLocation = CGF.EmitCheckSourceLocation(E->getBeginLoc()); |
| CheckTypeDesc = CGF.EmitCheckTypeDescriptor(QualType(MPT, 0)); |
| llvm::Constant *StaticData[] = { |
| llvm::ConstantInt::get(CGF.Int8Ty, CodeGenFunction::CFITCK_VMFCall), |
| CheckSourceLocation, |
| CheckTypeDesc, |
| }; |
| |
| if (CGM.getCodeGenOpts().SanitizeTrap.has(SanitizerKind::CFIMFCall)) { |
| CGF.EmitTrapCheck(CheckResult); |
| } else { |
| llvm::Value *AllVtables = llvm::MetadataAsValue::get( |
| CGM.getLLVMContext(), |
| llvm::MDString::get(CGM.getLLVMContext(), "all-vtables")); |
| llvm::Value *ValidVtable = Builder.CreateCall( |
| CGM.getIntrinsic(llvm::Intrinsic::type_test), {VTable, AllVtables}); |
| CGF.EmitCheck(std::make_pair(CheckResult, SanitizerKind::CFIMFCall), |
| SanitizerHandler::CFICheckFail, StaticData, |
| {VTable, ValidVtable}); |
| } |
| |
| FnVirtual = Builder.GetInsertBlock(); |
| } |
| } // End of sanitizer scope |
| |
| CGF.EmitBranch(FnEnd); |
| |
| // In the non-virtual path, the function pointer is actually a |
| // function pointer. |
| CGF.EmitBlock(FnNonVirtual); |
| llvm::Value *NonVirtualFn = |
| Builder.CreateIntToPtr(FnAsInt, FTy->getPointerTo(), "memptr.nonvirtualfn"); |
| |
| // Check the function pointer if CFI on member function pointers is enabled. |
| if (ShouldEmitCFICheck) { |
| CXXRecordDecl *RD = MPT->getClass()->getAsCXXRecordDecl(); |
| if (RD->hasDefinition()) { |
| CodeGenFunction::SanitizerScope SanScope(&CGF); |
| |
| llvm::Constant *StaticData[] = { |
| llvm::ConstantInt::get(CGF.Int8Ty, CodeGenFunction::CFITCK_NVMFCall), |
| CheckSourceLocation, |
| CheckTypeDesc, |
| }; |
| |
| llvm::Value *Bit = Builder.getFalse(); |
| llvm::Value *CastedNonVirtualFn = |
| Builder.CreateBitCast(NonVirtualFn, CGF.Int8PtrTy); |
| for (const CXXRecordDecl *Base : CGM.getMostBaseClasses(RD)) { |
| llvm::Metadata *MD = CGM.CreateMetadataIdentifierForType( |
| getContext().getMemberPointerType( |
| MPT->getPointeeType(), |
| getContext().getRecordType(Base).getTypePtr())); |
| llvm::Value *TypeId = |
| llvm::MetadataAsValue::get(CGF.getLLVMContext(), MD); |
| |
| llvm::Value *TypeTest = |
| Builder.CreateCall(CGM.getIntrinsic(llvm::Intrinsic::type_test), |
| {CastedNonVirtualFn, TypeId}); |
| Bit = Builder.CreateOr(Bit, TypeTest); |
| } |
| |
| CGF.EmitCheck(std::make_pair(Bit, SanitizerKind::CFIMFCall), |
| SanitizerHandler::CFICheckFail, StaticData, |
| {CastedNonVirtualFn, llvm::UndefValue::get(CGF.IntPtrTy)}); |
| |
| FnNonVirtual = Builder.GetInsertBlock(); |
| } |
| } |
| |
| // We're done. |
| CGF.EmitBlock(FnEnd); |
| llvm::PHINode *CalleePtr = Builder.CreatePHI(FTy->getPointerTo(), 2); |
| CalleePtr->addIncoming(VirtualFn, FnVirtual); |
| CalleePtr->addIncoming(NonVirtualFn, FnNonVirtual); |
| |
| CGCallee Callee(FPT, CalleePtr); |
| return Callee; |
| } |
| |
| /// Compute an l-value by applying the given pointer-to-member to a |
| /// base object. |
| llvm::Value *ItaniumCXXABI::EmitMemberDataPointerAddress( |
| CodeGenFunction &CGF, const Expr *E, Address Base, llvm::Value *MemPtr, |
| const MemberPointerType *MPT) { |
| assert(MemPtr->getType() == CGM.PtrDiffTy); |
| |
| CGBuilderTy &Builder = CGF.Builder; |
| |
| // Cast to char*. |
| Base = Builder.CreateElementBitCast(Base, CGF.Int8Ty); |
| |
| // Apply the offset, which we assume is non-null. |
| llvm::Value *Addr = |
| Builder.CreateInBoundsGEP(Base.getPointer(), MemPtr, "memptr.offset"); |
| |
| // Cast the address to the appropriate pointer type, adopting the |
| // address space of the base pointer. |
| llvm::Type *PType = CGF.ConvertTypeForMem(MPT->getPointeeType()) |
| ->getPointerTo(Base.getAddressSpace()); |
| return Builder.CreateBitCast(Addr, PType); |
| } |
| |
| /// Perform a bitcast, derived-to-base, or base-to-derived member pointer |
| /// conversion. |
| /// |
| /// Bitcast conversions are always a no-op under Itanium. |
| /// |
| /// Obligatory offset/adjustment diagram: |
| /// <-- offset --> <-- adjustment --> |
| /// |--------------------------|----------------------|--------------------| |
| /// ^Derived address point ^Base address point ^Member address point |
| /// |
| /// So when converting a base member pointer to a derived member pointer, |
| /// we add the offset to the adjustment because the address point has |
| /// decreased; and conversely, when converting a derived MP to a base MP |
| /// we subtract the offset from the adjustment because the address point |
| /// has increased. |
| /// |
| /// The standard forbids (at compile time) conversion to and from |
| /// virtual bases, which is why we don't have to consider them here. |
| /// |
| /// The standard forbids (at run time) casting a derived MP to a base |
| /// MP when the derived MP does not point to a member of the base. |
| /// This is why -1 is a reasonable choice for null data member |
| /// pointers. |
| llvm::Value * |
| ItaniumCXXABI::EmitMemberPointerConversion(CodeGenFunction &CGF, |
| const CastExpr *E, |
| llvm::Value *src) { |
| assert(E->getCastKind() == CK_DerivedToBaseMemberPointer || |
| E->getCastKind() == CK_BaseToDerivedMemberPointer || |
| E->getCastKind() == CK_ReinterpretMemberPointer); |
| |
| // Under Itanium, reinterprets don't require any additional processing. |
| if (E->getCastKind() == CK_ReinterpretMemberPointer) return src; |
| |
| // Use constant emission if we can. |
| if (isa<llvm::Constant>(src)) |
| return EmitMemberPointerConversion(E, cast<llvm::Constant>(src)); |
| |
| llvm::Constant *adj = getMemberPointerAdjustment(E); |
| if (!adj) return src; |
| |
| CGBuilderTy &Builder = CGF.Builder; |
| bool isDerivedToBase = (E->getCastKind() == CK_DerivedToBaseMemberPointer); |
| |
| const MemberPointerType *destTy = |
| E->getType()->castAs<MemberPointerType>(); |
| |
| // For member data pointers, this is just a matter of adding the |
| // offset if the source is non-null. |
| if (destTy->isMemberDataPointer()) { |
| llvm::Value *dst; |
| if (isDerivedToBase) |
| dst = Builder.CreateNSWSub(src, adj, "adj"); |
| else |
| dst = Builder.CreateNSWAdd(src, adj, "adj"); |
| |
| // Null check. |
| llvm::Value *null = llvm::Constant::getAllOnesValue(src->getType()); |
| llvm::Value *isNull = Builder.CreateICmpEQ(src, null, "memptr.isnull"); |
| return Builder.CreateSelect(isNull, src, dst); |
| } |
| |
| // The this-adjustment is left-shifted by 1 on ARM. |
| if (UseARMMethodPtrABI) { |
| uint64_t offset = cast<llvm::ConstantInt>(adj)->getZExtValue(); |
| offset <<= 1; |
| adj = llvm::ConstantInt::get(adj->getType(), offset); |
| } |
| |
| llvm::Value *srcAdj = Builder.CreateExtractValue(src, 1, "src.adj"); |
| llvm::Value *dstAdj; |
| if (isDerivedToBase) |
| dstAdj = Builder.CreateNSWSub(srcAdj, adj, "adj"); |
| else |
| dstAdj = Builder.CreateNSWAdd(srcAdj, adj, "adj"); |
| |
| return Builder.CreateInsertValue(src, dstAdj, 1); |
| } |
| |
| llvm::Constant * |
| ItaniumCXXABI::EmitMemberPointerConversion(const CastExpr *E, |
| llvm::Constant *src) { |
| assert(E->getCastKind() == CK_DerivedToBaseMemberPointer || |
| E->getCastKind() == CK_BaseToDerivedMemberPointer || |
| E->getCastKind() == CK_ReinterpretMemberPointer); |
| |
| // Under Itanium, reinterprets don't require any additional processing. |
| if (E->getCastKind() == CK_ReinterpretMemberPointer) return src; |
| |
| // If the adjustment is trivial, we don't need to do anything. |
| llvm::Constant *adj = getMemberPointerAdjustment(E); |
| if (!adj) return src; |
| |
| bool isDerivedToBase = (E->getCastKind() == CK_DerivedToBaseMemberPointer); |
| |
| const MemberPointerType *destTy = |
| E->getType()->castAs<MemberPointerType>(); |
| |
| // For member data pointers, this is just a matter of adding the |
| // offset if the source is non-null. |
| if (destTy->isMemberDataPointer()) { |
| // null maps to null. |
| if (src->isAllOnesValue()) return src; |
| |
| if (isDerivedToBase) |
| return llvm::ConstantExpr::getNSWSub(src, adj); |
| else |
| return llvm::ConstantExpr::getNSWAdd(src, adj); |
| } |
| |
| // The this-adjustment is left-shifted by 1 on ARM. |
| if (UseARMMethodPtrABI) { |
| uint64_t offset = cast<llvm::ConstantInt>(adj)->getZExtValue(); |
| offset <<= 1; |
| adj = llvm::ConstantInt::get(adj->getType(), offset); |
| } |
| |
| llvm::Constant *srcAdj = llvm::ConstantExpr::getExtractValue(src, 1); |
| llvm::Constant *dstAdj; |
| if (isDerivedToBase) |
| dstAdj = llvm::ConstantExpr::getNSWSub(srcAdj, adj); |
| else |
| dstAdj = llvm::ConstantExpr::getNSWAdd(srcAdj, adj); |
| |
| return llvm::ConstantExpr::getInsertValue(src, dstAdj, 1); |
| } |
| |
| llvm::Constant * |
| ItaniumCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) { |
| // Itanium C++ ABI 2.3: |
| // A NULL pointer is represented as -1. |
| if (MPT->isMemberDataPointer()) |
| return llvm::ConstantInt::get(CGM.PtrDiffTy, -1ULL, /*isSigned=*/true); |
| |
| llvm::Constant *Zero = llvm::ConstantInt::get(CGM.PtrDiffTy, 0); |
| llvm::Constant *Values[2] = { Zero, Zero }; |
| return llvm::ConstantStruct::getAnon(Values); |
| } |
| |
| llvm::Constant * |
| ItaniumCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT, |
| CharUnits offset) { |
| // Itanium C++ ABI 2.3: |
| // A pointer to data member is an offset from the base address of |
| // the class object containing it, represented as a ptrdiff_t |
| return llvm::ConstantInt::get(CGM.PtrDiffTy, offset.getQuantity()); |
| } |
| |
| llvm::Constant * |
| ItaniumCXXABI::EmitMemberFunctionPointer(const CXXMethodDecl *MD) { |
| return BuildMemberPointer(MD, CharUnits::Zero()); |
| } |
| |
| llvm::Constant *ItaniumCXXABI::BuildMemberPointer(const CXXMethodDecl *MD, |
| CharUnits ThisAdjustment) { |
| assert(MD->isInstance() && "Member function must not be static!"); |
| |
| CodeGenTypes &Types = CGM.getTypes(); |
| |
| // Get the function pointer (or index if this is a virtual function). |
| llvm::Constant *MemPtr[2]; |
| if (MD->isVirtual()) { |
| uint64_t Index = CGM.getItaniumVTableContext().getMethodVTableIndex(MD); |
| uint64_t VTableOffset; |
| if (CGM.getItaniumVTableContext().isRelativeLayout()) { |
| // Multiply by 4-byte relative offsets. |
| VTableOffset = Index * 4; |
| } else { |
| const ASTContext &Context = getContext(); |
| CharUnits PointerWidth = Context.toCharUnitsFromBits( |
| Context.getTargetInfo().getPointerWidth(0)); |
| VTableOffset = Index * PointerWidth.getQuantity(); |
| } |
| |
| if (UseARMMethodPtrABI) { |
| // ARM C++ ABI 3.2.1: |
| // This ABI specifies that adj contains twice the this |
| // adjustment, plus 1 if the member function is virtual. The |
| // least significant bit of adj then makes exactly the same |
| // discrimination as the least significant bit of ptr does for |
| // Itanium. |
| MemPtr[0] = llvm::ConstantInt::get(CGM.PtrDiffTy, VTableOffset); |
| MemPtr[1] = llvm::ConstantInt::get(CGM.PtrDiffTy, |
| 2 * ThisAdjustment.getQuantity() + 1); |
| } else { |
| // Itanium C++ ABI 2.3: |
| // For a virtual function, [the pointer field] is 1 plus the |
| // virtual table offset (in bytes) of the function, |
| // represented as a ptrdiff_t. |
| MemPtr[0] = llvm::ConstantInt::get(CGM.PtrDiffTy, VTableOffset + 1); |
| MemPtr[1] = llvm::ConstantInt::get(CGM.PtrDiffTy, |
| ThisAdjustment.getQuantity()); |
| } |
| } else { |
| 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; |
| } |
| llvm::Constant *addr = CGM.GetAddrOfFunction(MD, Ty); |
| |
| MemPtr[0] = llvm::ConstantExpr::getPtrToInt(addr, CGM.PtrDiffTy); |
| MemPtr[1] = llvm::ConstantInt::get(CGM.PtrDiffTy, |
| (UseARMMethodPtrABI ? 2 : 1) * |
| ThisAdjustment.getQuantity()); |
| } |
| |
| return llvm::ConstantStruct::getAnon(MemPtr); |
| } |
| |
| llvm::Constant *ItaniumCXXABI::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); |
| |
| if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MPD)) |
| return BuildMemberPointer(MD, ThisAdjustment); |
| |
| CharUnits FieldOffset = |
| getContext().toCharUnitsFromBits(getContext().getFieldOffset(MPD)); |
| return EmitMemberDataPointer(MPT, ThisAdjustment + FieldOffset); |
| } |
| |
| /// The comparison algorithm is pretty easy: the member pointers are |
| /// the same if they're either bitwise identical *or* both null. |
| /// |
| /// ARM is different here only because null-ness is more complicated. |
| llvm::Value * |
| ItaniumCXXABI::EmitMemberPointerComparison(CodeGenFunction &CGF, |
| llvm::Value *L, |
| llvm::Value *R, |
| const MemberPointerType *MPT, |
| bool Inequality) { |
| CGBuilderTy &Builder = CGF.Builder; |
| |
| 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; |
| } |
| |
| // Member data pointers are easy because there's a unique null |
| // value, so it just comes down to bitwise equality. |
| if (MPT->isMemberDataPointer()) |
| return Builder.CreateICmp(Eq, L, R); |
| |
| // For member function pointers, the tautologies are more complex. |
| // The Itanium tautology is: |
| // (L == R) <==> (L.ptr == R.ptr && (L.ptr == 0 || L.adj == R.adj)) |
| // The ARM tautology is: |
| // (L == R) <==> (L.ptr == R.ptr && |
| // (L.adj == R.adj || |
| // (L.ptr == 0 && ((L.adj|R.adj) & 1) == 0))) |
| // The inequality tautologies have exactly the same structure, except |
| // applying De Morgan's laws. |
| |
| llvm::Value *LPtr = Builder.CreateExtractValue(L, 0, "lhs.memptr.ptr"); |
| llvm::Value *RPtr = Builder.CreateExtractValue(R, 0, "rhs.memptr.ptr"); |
| |
| // This condition tests whether L.ptr == R.ptr. This must always be |
| // true for equality to hold. |
| llvm::Value *PtrEq = Builder.CreateICmp(Eq, LPtr, RPtr, "cmp.ptr"); |
| |
| // This condition, together with the assumption that L.ptr == R.ptr, |
| // tests whether the pointers are both null. ARM imposes an extra |
| // condition. |
| llvm::Value *Zero = llvm::Constant::getNullValue(LPtr->getType()); |
| llvm::Value *EqZero = Builder.CreateICmp(Eq, LPtr, Zero, "cmp.ptr.null"); |
| |
| // This condition tests whether L.adj == R.adj. If this isn't |
| // true, the pointers are unequal unless they're both null. |
| llvm::Value *LAdj = Builder.CreateExtractValue(L, 1, "lhs.memptr.adj"); |
| llvm::Value *RAdj = Builder.CreateExtractValue(R, 1, "rhs.memptr.adj"); |
| llvm::Value *AdjEq = Builder.CreateICmp(Eq, LAdj, RAdj, "cmp.adj"); |
| |
| // Null member function pointers on ARM clear the low bit of Adj, |
| // so the zero condition has to check that neither low bit is set. |
| if (UseARMMethodPtrABI) { |
| llvm::Value *One = llvm::ConstantInt::get(LPtr->getType(), 1); |
| |
| // Compute (l.adj | r.adj) & 1 and test it against zero. |
| llvm::Value *OrAdj = Builder.CreateOr(LAdj, RAdj, "or.adj"); |
| llvm::Value *OrAdjAnd1 = Builder.CreateAnd(OrAdj, One); |
| llvm::Value *OrAdjAnd1EqZero = Builder.CreateICmp(Eq, OrAdjAnd1, Zero, |
| "cmp.or.adj"); |
| EqZero = Builder.CreateBinOp(And, EqZero, OrAdjAnd1EqZero); |
| } |
| |
| // Tie together all our conditions. |
| llvm::Value *Result = Builder.CreateBinOp(Or, EqZero, AdjEq); |
| Result = Builder.CreateBinOp(And, PtrEq, Result, |
| Inequality ? "memptr.ne" : "memptr.eq"); |
| return Result; |
| } |
| |
| llvm::Value * |
| ItaniumCXXABI::EmitMemberPointerIsNotNull(CodeGenFunction &CGF, |
| llvm::Value *MemPtr, |
| const MemberPointerType *MPT) { |
| CGBuilderTy &Builder = CGF.Builder; |
| |
| /// For member data pointers, this is just a check against -1. |
| if (MPT->isMemberDataPointer()) { |
| assert(MemPtr->getType() == CGM.PtrDiffTy); |
| llvm::Value *NegativeOne = |
| llvm::Constant::getAllOnesValue(MemPtr->getType()); |
| return Builder.CreateICmpNE(MemPtr, NegativeOne, "memptr.tobool"); |
| } |
| |
| // In Itanium, a member function pointer is not null if 'ptr' is not null. |
| llvm::Value *Ptr = Builder.CreateExtractValue(MemPtr, 0, "memptr.ptr"); |
| |
| llvm::Constant *Zero = llvm::ConstantInt::get(Ptr->getType(), 0); |
| llvm::Value *Result = Builder.CreateICmpNE(Ptr, Zero, "memptr.tobool"); |
| |
| // On ARM, a member function pointer is also non-null if the low bit of 'adj' |
| // (the virtual bit) is set. |
| if (UseARMMethodPtrABI) { |
| llvm::Constant *One = llvm::ConstantInt::get(Ptr->getType(), 1); |
| llvm::Value *Adj = Builder.CreateExtractValue(MemPtr, 1, "memptr.adj"); |
| llvm::Value *VirtualBit = Builder.CreateAnd(Adj, One, "memptr.virtualbit"); |
| llvm::Value *IsVirtual = Builder.CreateICmpNE(VirtualBit, Zero, |
| "memptr.isvirtual"); |
| Result = Builder.CreateOr(Result, IsVirtual); |
| } |
| |
| return Result; |
| } |
| |
| bool ItaniumCXXABI::classifyReturnType(CGFunctionInfo &FI) const { |
| const CXXRecordDecl *RD = FI.getReturnType()->getAsCXXRecordDecl(); |
| if (!RD) |
| return false; |
| |
| // If C++ prohibits us from making a copy, return by address. |
| if (!RD->canPassInRegisters()) { |
| auto Align = CGM.getContext().getTypeAlignInChars(FI.getReturnType()); |
| FI.getReturnInfo() = ABIArgInfo::getIndirect(Align, /*ByVal=*/false); |
| return true; |
| } |
| return false; |
| } |
| |
| /// The Itanium ABI requires non-zero initialization only for data |
| /// member pointers, for which '0' is a valid offset. |
| bool ItaniumCXXABI::isZeroInitializable(const MemberPointerType *MPT) { |
| return MPT->isMemberFunctionPointer(); |
| } |
| |
| /// The Itanium ABI always places an offset to the complete object |
| /// at entry -2 in the vtable. |
| void ItaniumCXXABI::emitVirtualObjectDelete(CodeGenFunction &CGF, |
| const CXXDeleteExpr *DE, |
| Address Ptr, |
| QualType ElementType, |
| const CXXDestructorDecl *Dtor) { |
| bool UseGlobalDelete = DE->isGlobalDelete(); |
| if (UseGlobalDelete) { |
| // Derive the complete-object pointer, which is what we need |
| // to pass to the deallocation function. |
| |
| // Grab the vtable pointer as an intptr_t*. |
| auto *ClassDecl = |
| cast<CXXRecordDecl>(ElementType->castAs<RecordType>()->getDecl()); |
| llvm::Value *VTable = |
| CGF.GetVTablePtr(Ptr, CGF.IntPtrTy->getPointerTo(), ClassDecl); |
| |
| // Track back to entry -2 and pull out the offset there. |
| llvm::Value *OffsetPtr = CGF.Builder.CreateConstInBoundsGEP1_64( |
| VTable, -2, "complete-offset.ptr"); |
| llvm::Value *Offset = |
| CGF.Builder.CreateAlignedLoad(OffsetPtr, CGF.getPointerAlign()); |
| |
| // Apply the offset. |
| llvm::Value *CompletePtr = |
| CGF.Builder.CreateBitCast(Ptr.getPointer(), CGF.Int8PtrTy); |
| CompletePtr = CGF.Builder.CreateInBoundsGEP(CompletePtr, Offset); |
| |
| // If we're supposed to call the global delete, make sure we do so |
| // even if the destructor throws. |
| CGF.pushCallObjectDeleteCleanup(DE->getOperatorDelete(), CompletePtr, |
| ElementType); |
| } |
| |
| // FIXME: Provide a source location here even though there's no |
| // CXXMemberCallExpr for dtor call. |
| CXXDtorType DtorType = UseGlobalDelete ? Dtor_Complete : Dtor_Deleting; |
| EmitVirtualDestructorCall(CGF, Dtor, DtorType, Ptr, DE); |
| |
| if (UseGlobalDelete) |
| CGF.PopCleanupBlock(); |
| } |
| |
| void ItaniumCXXABI::emitRethrow(CodeGenFunction &CGF, bool isNoReturn) { |
| // void __cxa_rethrow(); |
| |
| llvm::FunctionType *FTy = |
| llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false); |
| |
| llvm::FunctionCallee Fn = CGM.CreateRuntimeFunction(FTy, "__cxa_rethrow"); |
| |
| if (isNoReturn) |
| CGF.EmitNoreturnRuntimeCallOrInvoke(Fn, None); |
| else |
| CGF.EmitRuntimeCallOrInvoke(Fn); |
| } |
| |
| static llvm::FunctionCallee getAllocateExceptionFn(CodeGenModule &CGM) { |
| // void *__cxa_allocate_exception(size_t thrown_size); |
| |
| llvm::FunctionType *FTy = |
| llvm::FunctionType::get(CGM.Int8PtrTy, CGM.SizeTy, /*isVarArg=*/false); |
| |
| return CGM.CreateRuntimeFunction(FTy, "__cxa_allocate_exception"); |
| } |
| |
| static llvm::FunctionCallee getThrowFn(CodeGenModule &CGM) { |
| // void __cxa_throw(void *thrown_exception, std::type_info *tinfo, |
| // void (*dest) (void *)); |
| |
| llvm::Type *Args[3] = { CGM.Int8PtrTy, CGM.Int8PtrTy, CGM.Int8PtrTy }; |
| llvm::FunctionType *FTy = |
| llvm::FunctionType::get(CGM.VoidTy, Args, /*isVarArg=*/false); |
| |
| return CGM.CreateRuntimeFunction(FTy, "__cxa_throw"); |
| } |
| |
| void ItaniumCXXABI::emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) { |
| QualType ThrowType = E->getSubExpr()->getType(); |
| // Now allocate the exception object. |
| llvm::Type *SizeTy = CGF.ConvertType(getContext().getSizeType()); |
| uint64_t TypeSize = getContext().getTypeSizeInChars(ThrowType).getQuantity(); |
| |
| llvm::FunctionCallee AllocExceptionFn = getAllocateExceptionFn(CGM); |
| llvm::CallInst *ExceptionPtr = CGF.EmitNounwindRuntimeCall( |
| AllocExceptionFn, llvm::ConstantInt::get(SizeTy, TypeSize), "exception"); |
| |
| CharUnits ExnAlign = CGF.getContext().getExnObjectAlignment(); |
| CGF.EmitAnyExprToExn(E->getSubExpr(), Address(ExceptionPtr, ExnAlign)); |
| |
| // Now throw the exception. |
| llvm::Constant *TypeInfo = CGM.GetAddrOfRTTIDescriptor(ThrowType, |
| /*ForEH=*/true); |
| |
| // The address of the destructor. If the exception type has a |
| // trivial destructor (or isn't a record), we just pass null. |
| llvm::Constant *Dtor = nullptr; |
| if (const RecordType *RecordTy = ThrowType->getAs<RecordType>()) { |
| CXXRecordDecl *Record = cast<CXXRecordDecl>(RecordTy->getDecl()); |
| if (!Record->hasTrivialDestructor()) { |
| CXXDestructorDecl *DtorD = Record->getDestructor(); |
| Dtor = CGM.getAddrOfCXXStructor(GlobalDecl(DtorD, Dtor_Complete)); |
| Dtor = llvm::ConstantExpr::getBitCast(Dtor, CGM.Int8PtrTy); |
| } |
| } |
| if (!Dtor) Dtor = llvm::Constant::getNullValue(CGM.Int8PtrTy); |
| |
| llvm::Value *args[] = { ExceptionPtr, TypeInfo, Dtor }; |
| CGF.EmitNoreturnRuntimeCallOrInvoke(getThrowFn(CGM), args); |
| } |
| |
| static llvm::FunctionCallee getItaniumDynamicCastFn(CodeGenFunction &CGF) { |
| // void *__dynamic_cast(const void *sub, |
| // const abi::__class_type_info *src, |
| // const abi::__class_type_info *dst, |
| // std::ptrdiff_t src2dst_offset); |
| |
| llvm::Type *Int8PtrTy = CGF.Int8PtrTy; |
| llvm::Type *PtrDiffTy = |
| CGF.ConvertType(CGF.getContext().getPointerDiffType()); |
| |
| llvm::Type *Args[4] = { Int8PtrTy, Int8PtrTy, Int8PtrTy, PtrDiffTy }; |
| |
| llvm::FunctionType *FTy = llvm::FunctionType::get(Int8PtrTy, Args, false); |
| |
| // Mark the function as nounwind readonly. |
| llvm::Attribute::AttrKind FuncAttrs[] = { llvm::Attribute::NoUnwind, |
| llvm::Attribute::ReadOnly }; |
| llvm::AttributeList Attrs = llvm::AttributeList::get( |
| CGF.getLLVMContext(), llvm::AttributeList::FunctionIndex, FuncAttrs); |
| |
| return CGF.CGM.CreateRuntimeFunction(FTy, "__dynamic_cast", Attrs); |
| } |
| |
| static llvm::FunctionCallee getBadCastFn(CodeGenFunction &CGF) { |
| // void __cxa_bad_cast(); |
| llvm::FunctionType *FTy = llvm::FunctionType::get(CGF.VoidTy, false); |
| return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_bad_cast"); |
| } |
| |
| /// Compute the src2dst_offset hint as described in the |
| /// Itanium C++ ABI [2.9.7] |
| static CharUnits computeOffsetHint(ASTContext &Context, |
| const CXXRecordDecl *Src, |
| const CXXRecordDecl *Dst) { |
| CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, |
| /*DetectVirtual=*/false); |
| |
| // If Dst is not derived from Src we can skip the whole computation below and |
| // return that Src is not a public base of Dst. Record all inheritance paths. |
| if (!Dst->isDerivedFrom(Src, Paths)) |
| return CharUnits::fromQuantity(-2ULL); |
| |
| unsigned NumPublicPaths = 0; |
| CharUnits Offset; |
| |
| // Now walk all possible inheritance paths. |
| for (const CXXBasePath &Path : Paths) { |
| if (Path.Access != AS_public) // Ignore non-public inheritance. |
| continue; |
| |
| ++NumPublicPaths; |
| |
| for (const CXXBasePathElement &PathElement : Path) { |
| // If the path contains a virtual base class we can't give any hint. |
| // -1: no hint. |
| if (PathElement.Base->isVirtual()) |
| return CharUnits::fromQuantity(-1ULL); |
| |
| if (NumPublicPaths > 1) // Won't use offsets, skip computation. |
| continue; |
| |
| // Accumulate the base class offsets. |
| const ASTRecordLayout &L = Context.getASTRecordLayout(PathElement.Class); |
| Offset += L.getBaseClassOffset( |
| PathElement.Base->getType()->getAsCXXRecordDecl()); |
| } |
| } |
| |
| // -2: Src is not a public base of Dst. |
| if (NumPublicPaths == 0) |
| return CharUnits::fromQuantity(-2ULL); |
| |
| // -3: Src is a multiple public base type but never a virtual base type. |
| if (NumPublicPaths > 1) |
| return CharUnits::fromQuantity(-3ULL); |
| |
| // Otherwise, the Src type is a unique public nonvirtual base type of Dst. |
| // Return the offset of Src from the origin of Dst. |
| return Offset; |
| } |
| |
| static llvm::FunctionCallee getBadTypeidFn(CodeGenFunction &CGF) { |
| // void __cxa_bad_typeid(); |
| llvm::FunctionType *FTy = llvm::FunctionType::get(CGF.VoidTy, false); |
| |
| return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_bad_typeid"); |
| } |
| |
| bool ItaniumCXXABI::shouldTypeidBeNullChecked(bool IsDeref, |
| QualType SrcRecordTy) { |
| return IsDeref; |
| } |
| |
| void ItaniumCXXABI::EmitBadTypeidCall(CodeGenFunction &CGF) { |
| llvm::FunctionCallee Fn = getBadTypeidFn(CGF); |
| llvm::CallBase *Call = CGF.EmitRuntimeCallOrInvoke(Fn); |
| Call->setDoesNotReturn(); |
| CGF.Builder.CreateUnreachable(); |
| } |
| |
| llvm::Value *ItaniumCXXABI::EmitTypeid(CodeGenFunction &CGF, |
| QualType SrcRecordTy, |
| Address ThisPtr, |
| llvm::Type *StdTypeInfoPtrTy) { |
| auto *ClassDecl = |
| cast<CXXRecordDecl>(SrcRecordTy->castAs<RecordType>()->getDecl()); |
| llvm::Value *Value = |
| CGF.GetVTablePtr(ThisPtr, StdTypeInfoPtrTy->getPointerTo(), ClassDecl); |
| |
| if (CGM.getItaniumVTableContext().isRelativeLayout()) { |
| // Load the type info. |
| Value = CGF.Builder.CreateBitCast(Value, CGM.Int8PtrTy); |
| Value = CGF.Builder.CreateCall( |
| CGM.getIntrinsic(llvm::Intrinsic::load_relative, {CGM.Int32Ty}), |
| {Value, llvm::ConstantInt::get(CGM.Int32Ty, -4)}); |
| |
| // Setup to dereference again since this is a proxy we accessed. |
| Value = CGF.Builder.CreateBitCast(Value, StdTypeInfoPtrTy->getPointerTo()); |
| } else { |
| // Load the type info. |
| Value = CGF.Builder.CreateConstInBoundsGEP1_64(Value, -1ULL); |
| } |
| return CGF.Builder.CreateAlignedLoad(Value, CGF.getPointerAlign()); |
| } |
| |
| bool ItaniumCXXABI::shouldDynamicCastCallBeNullChecked(bool SrcIsPtr, |
| QualType SrcRecordTy) { |
| return SrcIsPtr; |
| } |
| |
| llvm::Value *ItaniumCXXABI::EmitDynamicCastCall( |
| CodeGenFunction &CGF, Address ThisAddr, QualType SrcRecordTy, |
| QualType DestTy, QualType DestRecordTy, llvm::BasicBlock *CastEnd) { |
| llvm::Type *PtrDiffLTy = |
| CGF.ConvertType(CGF.getContext().getPointerDiffType()); |
| llvm::Type *DestLTy = CGF.ConvertType(DestTy); |
| |
| llvm::Value *SrcRTTI = |
| CGF.CGM.GetAddrOfRTTIDescriptor(SrcRecordTy.getUnqualifiedType()); |
| llvm::Value *DestRTTI = |
| CGF.CGM.GetAddrOfRTTIDescriptor(DestRecordTy.getUnqualifiedType()); |
| |
| // Compute the offset hint. |
| const CXXRecordDecl *SrcDecl = SrcRecordTy->getAsCXXRecordDecl(); |
| const CXXRecordDecl *DestDecl = DestRecordTy->getAsCXXRecordDecl(); |
| llvm::Value *OffsetHint = llvm::ConstantInt::get( |
| PtrDiffLTy, |
| computeOffsetHint(CGF.getContext(), SrcDecl, DestDecl).getQuantity()); |
| |
| // Emit the call to __dynamic_cast. |
| llvm::Value *Value = ThisAddr.getPointer(); |
| Value = CGF.EmitCastToVoidPtr(Value); |
| |
| llvm::Value *args[] = {Value, SrcRTTI, DestRTTI, OffsetHint}; |
| Value = CGF.EmitNounwindRuntimeCall(getItaniumDynamicCastFn(CGF), args); |
| Value = CGF.Builder.CreateBitCast(Value, DestLTy); |
| |
| /// C++ [expr.dynamic.cast]p9: |
| /// A failed cast to reference type throws std::bad_cast |
| if (DestTy->isReferenceType()) { |
| llvm::BasicBlock *BadCastBlock = |
| CGF.createBasicBlock("dynamic_cast.bad_cast"); |
| |
| llvm::Value *IsNull = CGF.Builder.CreateIsNull(Value); |
| CGF.Builder.CreateCondBr(IsNull, BadCastBlock, CastEnd); |
| |
| CGF.EmitBlock(BadCastBlock); |
| EmitBadCastCall(CGF); |
| } |
| |
| return Value; |
| } |
| |
| llvm::Value *ItaniumCXXABI::EmitDynamicCastToVoid(CodeGenFunction &CGF, |
| Address ThisAddr, |
| QualType SrcRecordTy, |
| QualType DestTy) { |
| llvm::Type *DestLTy = CGF.ConvertType(DestTy); |
| auto *ClassDecl = |
| cast<CXXRecordDecl>(SrcRecordTy->castAs<RecordType>()->getDecl()); |
| llvm::Value *OffsetToTop; |
| if (CGM.getItaniumVTableContext().isRelativeLayout()) { |
| // Get the vtable pointer. |
| llvm::Value *VTable = |
| CGF.GetVTablePtr(ThisAddr, CGM.Int32Ty->getPointerTo(), ClassDecl); |
| |
| // Get the offset-to-top from the vtable. |
| OffsetToTop = |
| CGF.Builder.CreateConstInBoundsGEP1_32(/*Type=*/nullptr, VTable, -2U); |
| OffsetToTop = CGF.Builder.CreateAlignedLoad( |
| OffsetToTop, CharUnits::fromQuantity(4), "offset.to.top"); |
| } else { |
| llvm::Type *PtrDiffLTy = |
| CGF.ConvertType(CGF.getContext().getPointerDiffType()); |
| |
| // Get the vtable pointer. |
| llvm::Value *VTable = |
| CGF.GetVTablePtr(ThisAddr, PtrDiffLTy->getPointerTo(), ClassDecl); |
| |
| // Get the offset-to-top from the vtable. |
| OffsetToTop = CGF.Builder.CreateConstInBoundsGEP1_64(VTable, -2ULL); |
| OffsetToTop = CGF.Builder.CreateAlignedLoad( |
| OffsetToTop, CGF.getPointerAlign(), "offset.to.top"); |
| } |
| // Finally, add the offset to the pointer. |
| llvm::Value *Value = ThisAddr.getPointer(); |
| Value = CGF.EmitCastToVoidPtr(Value); |
| Value = CGF.Builder.CreateInBoundsGEP(Value, OffsetToTop); |
| return CGF.Builder.CreateBitCast(Value, DestLTy); |
| } |
| |
| bool ItaniumCXXABI::EmitBadCastCall(CodeGenFunction &CGF) { |
| llvm::FunctionCallee Fn = getBadCastFn(CGF); |
| llvm::CallBase *Call = CGF.EmitRuntimeCallOrInvoke(Fn); |
| Call->setDoesNotReturn(); |
| CGF.Builder.CreateUnreachable(); |
| return true; |
| } |
| |
| llvm::Value * |
| ItaniumCXXABI::GetVirtualBaseClassOffset(CodeGenFunction &CGF, |
| Address This, |
| const CXXRecordDecl *ClassDecl, |
| const CXXRecordDecl *BaseClassDecl) { |
| llvm::Value *VTablePtr = CGF.GetVTablePtr(This, CGM.Int8PtrTy, ClassDecl); |
| CharUnits VBaseOffsetOffset = |
| CGM.getItaniumVTableContext().getVirtualBaseOffsetOffset(ClassDecl, |
| BaseClassDecl); |
| llvm::Value *VBaseOffsetPtr = |
| CGF.Builder.CreateConstGEP1_64(VTablePtr, VBaseOffsetOffset.getQuantity(), |
| "vbase.offset.ptr"); |
| |
| llvm::Value *VBaseOffset; |
| if (CGM.getItaniumVTableContext().isRelativeLayout()) { |
| VBaseOffsetPtr = |
| CGF.Builder.CreateBitCast(VBaseOffsetPtr, CGF.Int32Ty->getPointerTo()); |
| VBaseOffset = CGF.Builder.CreateAlignedLoad( |
| VBaseOffsetPtr, CharUnits::fromQuantity(4), "vbase.offset"); |
| } else { |
| VBaseOffsetPtr = CGF.Builder.CreateBitCast(VBaseOffsetPtr, |
| CGM.PtrDiffTy->getPointerTo()); |
| VBaseOffset = CGF.Builder.CreateAlignedLoad( |
| VBaseOffsetPtr, CGF.getPointerAlign(), "vbase.offset"); |
| } |
| return VBaseOffset; |
| } |
| |
| void ItaniumCXXABI::EmitCXXConstructors(const CXXConstructorDecl *D) { |
| // Just make sure we're in sync with TargetCXXABI. |
| assert(CGM.getTarget().getCXXABI().hasConstructorVariants()); |
| |
| // The constructor used for constructing this as a base class; |
| // ignores virtual bases. |
| CGM.EmitGlobal(GlobalDecl(D, Ctor_Base)); |
| |
| // The constructor used for constructing this as a complete class; |
| // constructs the virtual bases, then calls the base constructor. |
| if (!D->getParent()->isAbstract()) { |
| // We don't need to emit the complete ctor if the class is abstract. |
| CGM.EmitGlobal(GlobalDecl(D, Ctor_Complete)); |
| } |
| } |
| |
| CGCXXABI::AddedStructorArgCounts |
| ItaniumCXXABI::buildStructorSignature(GlobalDecl GD, |
| SmallVectorImpl<CanQualType> &ArgTys) { |
| ASTContext &Context = getContext(); |
| |
| // All parameters are already in place except VTT, which goes after 'this'. |
| // These are Clang types, so we don't need to worry about sret yet. |
| |
| // Check if we need to add a VTT parameter (which has type void **). |
| if ((isa<CXXConstructorDecl>(GD.getDecl()) ? GD.getCtorType() == Ctor_Base |
| : GD.getDtorType() == Dtor_Base) && |
| cast<CXXMethodDecl>(GD.getDecl())->getParent()->getNumVBases() != 0) { |
| ArgTys.insert(ArgTys.begin() + 1, |
| Context.getPointerType(Context.VoidPtrTy)); |
| return AddedStructorArgCounts::prefix(1); |
| } |
| return AddedStructorArgCounts{}; |
| } |
| |
| void ItaniumCXXABI::EmitCXXDestructors(const CXXDestructorDecl *D) { |
| // The destructor used for destructing this as a base class; ignores |
| // virtual bases. |
| CGM.EmitGlobal(GlobalDecl(D, Dtor_Base)); |
| |
| // The destructor used for destructing this as a most-derived class; |
| // call the base destructor and then destructs any virtual bases. |
| CGM.EmitGlobal(GlobalDecl(D, Dtor_Complete)); |
| |
| // The destructor in a virtual table is always a 'deleting' |
| // destructor, which calls the complete destructor and then uses the |
| // appropriate operator delete. |
| if (D->isVirtual()) |
| CGM.EmitGlobal(GlobalDecl(D, Dtor_Deleting)); |
| } |
| |
| void ItaniumCXXABI::addImplicitStructorParams(CodeGenFunction &CGF, |
| QualType &ResTy, |
| FunctionArgList &Params) { |
| const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl()); |
| assert(isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD)); |
| |
| // Check if we need a VTT parameter as well. |
| if (NeedsVTTParameter(CGF.CurGD)) { |
| ASTContext &Context = getContext(); |
| |
| // FIXME: avoid the fake decl |
| QualType T = Context.getPointerType(Context.VoidPtrTy); |
| auto *VTTDecl = ImplicitParamDecl::Create( |
| Context, /*DC=*/nullptr, MD->getLocation(), &Context.Idents.get("vtt"), |
| T, ImplicitParamDecl::CXXVTT); |
| Params.insert(Params.begin() + 1, VTTDecl); |
| getStructorImplicitParamDecl(CGF) = VTTDecl; |
| } |
| } |
| |
| void ItaniumCXXABI::EmitInstanceFunctionProlog(CodeGenFunction &CGF) { |
| // Naked functions have no prolog. |
| if (CGF.CurFuncDecl && CGF.CurFuncDecl->hasAttr<NakedAttr>()) |
| return; |
| |
| /// Initialize the 'this' slot. In the Itanium C++ ABI, no prologue |
| /// adjustments are required, because they are all handled by thunks. |
| setCXXABIThisValue(CGF, loadIncomingCXXThis(CGF)); |
| |
| /// Initialize the 'vtt' slot if needed. |
| if (getStructorImplicitParamDecl(CGF)) { |
| getStructorImplicitParamValue(CGF) = CGF.Builder.CreateLoad( |
| CGF.GetAddrOfLocalVar(getStructorImplicitParamDecl(CGF)), "vtt"); |
| } |
| |
| /// 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); |
| } |
| |
| CGCXXABI::AddedStructorArgs ItaniumCXXABI::getImplicitConstructorArgs( |
| CodeGenFunction &CGF, const CXXConstructorDecl *D, CXXCtorType Type, |
| bool ForVirtualBase, bool Delegating) { |
| if (!NeedsVTTParameter(GlobalDecl(D, Type))) |
| return AddedStructorArgs{}; |
| |
| // Insert the implicit 'vtt' argument as the second argument. |
| llvm::Value *VTT = |
| CGF.GetVTTParameter(GlobalDecl(D, Type), ForVirtualBase, Delegating); |
| QualType VTTTy = getContext().getPointerType(getContext().VoidPtrTy); |
| return AddedStructorArgs::prefix({{VTT, VTTTy}}); |
| } |
| |
| llvm::Value *ItaniumCXXABI::getCXXDestructorImplicitParam( |
| CodeGenFunction &CGF, const CXXDestructorDecl *DD, CXXDtorType Type, |
| bool ForVirtualBase, bool Delegating) { |
| GlobalDecl GD(DD, Type); |
| return CGF.GetVTTParameter(GD, ForVirtualBase, Delegating); |
| } |
| |
| void ItaniumCXXABI::EmitDestructorCall(CodeGenFunction &CGF, |
| const CXXDestructorDecl *DD, |
| CXXDtorType Type, bool ForVirtualBase, |
| bool Delegating, Address This, |
| QualType ThisTy) { |
| GlobalDecl GD(DD, Type); |
| llvm::Value *VTT = |
| getCXXDestructorImplicitParam(CGF, DD, Type, ForVirtualBase, Delegating); |
| QualType VTTTy = getContext().getPointerType(getContext().VoidPtrTy); |
| |
| CGCallee Callee; |
| if (getContext().getLangOpts().AppleKext && |
| Type != Dtor_Base && DD->isVirtual()) |
| Callee = CGF.BuildAppleKextVirtualDestructorCall(DD, Type, DD->getParent()); |
| else |
| Callee = CGCallee::forDirect(CGM.getAddrOfCXXStructor(GD), GD); |
| |
| CGF.EmitCXXDestructorCall(GD, Callee, This.getPointer(), ThisTy, VTT, VTTTy, |
| nullptr); |
| } |
| |
| void ItaniumCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT, |
| const CXXRecordDecl *RD) { |
| llvm::GlobalVariable *VTable = getAddrOfVTable(RD, CharUnits()); |
| if (VTable->hasInitializer()) |
| return; |
| |
| ItaniumVTableContext &VTContext = CGM.getItaniumVTableContext(); |
| const VTableLayout &VTLayout = VTContext.getVTableLayout(RD); |
| llvm::GlobalVariable::LinkageTypes Linkage = CGM.getVTableLinkage(RD); |
| llvm::Constant *RTTI = |
| CGM.GetAddrOfRTTIDescriptor(CGM.getContext().getTagDeclType(RD)); |
| |
| // Create and set the initializer. |
| ConstantInitBuilder builder(CGM); |
| auto components = builder.beginStruct(); |
| CGVT.createVTableInitializer(components, VTLayout, RTTI, |
| llvm::GlobalValue::isLocalLinkage(Linkage)); |
| components.finishAndSetAsInitializer(VTable); |
| |
| // Set the correct linkage. |
| VTable->setLinkage(Linkage); |
| |
| if (CGM.supportsCOMDAT() && VTable->isWeakForLinker()) |
| VTable->setComdat(CGM.getModule().getOrInsertComdat(VTable->getName())); |
| |
| // Set the right visibility. |
| CGM.setGVProperties(VTable, RD); |
| |
| // If this is the magic class __cxxabiv1::__fundamental_type_info, |
| // we will emit the typeinfo for the fundamental types. This is the |
| // same behaviour as GCC. |
| const DeclContext *DC = RD->getDeclContext(); |
| if (RD->getIdentifier() && |
| RD->getIdentifier()->isStr("__fundamental_type_info") && |
| isa<NamespaceDecl>(DC) && cast<NamespaceDecl>(DC)->getIdentifier() && |
| cast<NamespaceDecl>(DC)->getIdentifier()->isStr("__cxxabiv1") && |
| DC->getParent()->isTranslationUnit()) |
| EmitFundamentalRTTIDescriptors(RD); |
| |
| if (!VTable->isDeclarationForLinker()) |
| CGM.EmitVTableTypeMetadata(RD, VTable, VTLayout); |
| |
| if (VTContext.isRelativeLayout() && !VTable->isDSOLocal()) |
| CGVT.GenerateRelativeVTableAlias(VTable, VTable->getName()); |
| } |
| |
| bool ItaniumCXXABI::isVirtualOffsetNeededForVTableField( |
| CodeGenFunction &CGF, CodeGenFunction::VPtr Vptr) { |
| if (Vptr.NearestVBase == nullptr) |
| return false; |
| return NeedsVTTParameter(CGF.CurGD); |
| } |
| |
| llvm::Value *ItaniumCXXABI::getVTableAddressPointInStructor( |
| CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, BaseSubobject Base, |
| const CXXRecordDecl *NearestVBase) { |
| |
| if ((Base.getBase()->getNumVBases() || NearestVBase != nullptr) && |
| NeedsVTTParameter(CGF.CurGD)) { |
| return getVTableAddressPointInStructorWithVTT(CGF, VTableClass, Base, |
| NearestVBase); |
| } |
| return getVTableAddressPoint(Base, VTableClass); |
| } |
| |
| llvm::Constant * |
| ItaniumCXXABI::getVTableAddressPoint(BaseSubobject Base, |
| const CXXRecordDecl *VTableClass) { |
| llvm::GlobalValue *VTable = getAddrOfVTable(VTableClass, CharUnits()); |
| |
| // Find the appropriate vtable within the vtable group, and the address point |
| // within that vtable. |
| VTableLayout::AddressPointLocation AddressPoint = |
| CGM.getItaniumVTableContext() |
| .getVTableLayout(VTableClass) |
| .getAddressPoint(Base); |
| llvm::Value *Indices[] = { |
| llvm::ConstantInt::get(CGM.Int32Ty, 0), |
| llvm::ConstantInt::get(CGM.Int32Ty, AddressPoint.VTableIndex), |
| llvm::ConstantInt::get(CGM.Int32Ty, AddressPoint.AddressPointIndex), |
| }; |
| |
| return llvm::ConstantExpr::getGetElementPtr(VTable->getValueType(), VTable, |
| Indices, /*InBounds=*/true, |
| /*InRangeIndex=*/1); |
| } |
| |
| llvm::Value *ItaniumCXXABI::getVTableAddressPointInStructorWithVTT( |
| CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, BaseSubobject Base, |
| const CXXRecordDecl *NearestVBase) { |
| assert((Base.getBase()->getNumVBases() || NearestVBase != nullptr) && |
| NeedsVTTParameter(CGF.CurGD) && "This class doesn't have VTT"); |
| |
| // Get the secondary vpointer index. |
| uint64_t VirtualPointerIndex = |
| CGM.getVTables().getSecondaryVirtualPointerIndex(VTableClass, Base); |
| |
| /// Load the VTT. |
| llvm::Value *VTT = CGF.LoadCXXVTT(); |
| if (VirtualPointerIndex) |
| VTT = CGF.Builder.CreateConstInBoundsGEP1_64(VTT, VirtualPointerIndex); |
| |
| // And load the address point from the VTT. |
| return CGF.Builder.CreateAlignedLoad(VTT, CGF.getPointerAlign()); |
| } |
| |
| llvm::Constant *ItaniumCXXABI::getVTableAddressPointForConstExpr( |
| BaseSubobject Base, const CXXRecordDecl *VTableClass) { |
| return getVTableAddressPoint(Base, VTableClass); |
| } |
| |
| llvm::GlobalVariable *ItaniumCXXABI::getAddrOfVTable(const CXXRecordDecl *RD, |
| CharUnits VPtrOffset) { |
| assert(VPtrOffset.isZero() && "Itanium ABI only supports zero vptr offsets"); |
| |
| llvm::GlobalVariable *&VTable = VTables[RD]; |
| if (VTable) |
| return VTable; |
| |
| // Queue up this vtable for possible deferred emission. |
| CGM.addDeferredVTable(RD); |
| |
| SmallString<256> Name; |
| llvm::raw_svector_ostream Out(Name); |
| getMangleContext().mangleCXXVTable(RD, Out); |
| |
| const VTableLayout &VTLayout = |
| CGM.getItaniumVTableContext().getVTableLayout(RD); |
| llvm::Type *VTableType = CGM.getVTables().getVTableType(VTLayout); |
| |
| // Use pointer alignment for the vtable. Otherwise we would align them based |
| // on the size of the initializer which doesn't make sense as only single |
| // values are read. |
| unsigned PAlign = CGM.getItaniumVTableContext().isRelativeLayout() |
| ? 32 |
| : CGM.getTarget().getPointerAlign(0); |
| |
| VTable = CGM.CreateOrReplaceCXXRuntimeVariable( |
| Name, VTableType, llvm::GlobalValue::ExternalLinkage, |
| getContext().toCharUnitsFromBits(PAlign).getQuantity()); |
| VTable->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global); |
| |
| CGM.setGVProperties(VTable, RD); |
| |
| return VTable; |
| } |
| |
| CGCallee ItaniumCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF, |
| GlobalDecl GD, |
| Address This, |
| llvm::Type *Ty, |
| SourceLocation Loc) { |
| auto *MethodDecl = cast<CXXMethodDecl>(GD.getDecl()); |
| llvm::Value *VTable = CGF.GetVTablePtr( |
| This, Ty->getPointerTo()->getPointerTo(), MethodDecl->getParent()); |
| |
| uint64_t VTableIndex = CGM.getItaniumVTableContext().getMethodVTableIndex(GD); |
| llvm::Value *VFunc; |
| if (CGF.ShouldEmitVTableTypeCheckedLoad(MethodDecl->getParent())) { |
| VFunc = CGF.EmitVTableTypeCheckedLoad( |
| MethodDecl->getParent(), VTable, |
| VTableIndex * CGM.getContext().getTargetInfo().getPointerWidth(0) / 8); |
| } else { |
| CGF.EmitTypeMetadataCodeForVCall(MethodDecl->getParent(), VTable, Loc); |
| |
| llvm::Value *VFuncLoad; |
| if (CGM.getItaniumVTableContext().isRelativeLayout()) { |
| VTable = CGF.Builder.CreateBitCast(VTable, CGM.Int8PtrTy); |
| llvm::Value *Load = CGF.Builder.CreateCall( |
| CGM.getIntrinsic(llvm::Intrinsic::load_relative, {CGM.Int32Ty}), |
| {VTable, llvm::ConstantInt::get(CGM.Int32Ty, 4 * VTableIndex)}); |
| VFuncLoad = CGF.Builder.CreateBitCast(Load, Ty->getPointerTo()); |
| } else { |
| VTable = |
| CGF.Builder.CreateBitCast(VTable, Ty->getPointerTo()->getPointerTo()); |
| llvm::Value *VTableSlotPtr = |
| CGF.Builder.CreateConstInBoundsGEP1_64(VTable, VTableIndex, "vfn"); |
| VFuncLoad = |
| CGF.Builder.CreateAlignedLoad(VTableSlotPtr, CGF.getPointerAlign()); |
| } |
| |
| // Add !invariant.load md to virtual function load to indicate that |
| // function didn't change inside vtable. |
| // It's safe to add it without -fstrict-vtable-pointers, but it would not |
| // help in devirtualization because it will only matter if we will have 2 |
| // the same virtual function loads from the same vtable load, which won't |
| // happen without enabled devirtualization with -fstrict-vtable-pointers. |
| if (CGM.getCodeGenOpts().OptimizationLevel > 0 && |
| CGM.getCodeGenOpts().StrictVTablePointers) { |
| if (auto *VFuncLoadInstr = dyn_cast<llvm::Instruction>(VFuncLoad)) { |
| VFuncLoadInstr->setMetadata( |
| llvm::LLVMContext::MD_invariant_load, |
| llvm::MDNode::get(CGM.getLLVMContext(), |
| llvm::ArrayRef<llvm::Metadata *>())); |
| } |
| } |
| VFunc = VFuncLoad; |
| } |
| |
| CGCallee Callee(GD, VFunc); |
| return Callee; |
| } |
| |
| llvm::Value *ItaniumCXXABI::EmitVirtualDestructorCall( |
| CodeGenFunction &CGF, const CXXDestructorDecl *Dtor, CXXDtorType DtorType, |
| Address This, DeleteOrMemberCallExpr E) { |
| auto *CE = E.dyn_cast<const CXXMemberCallExpr *>(); |
| auto *D = E.dyn_cast<const CXXDeleteExpr *>(); |
| assert((CE != nullptr) ^ (D != nullptr)); |
| assert(CE == nullptr || CE->arg_begin() == CE->arg_end()); |
| assert(DtorType == Dtor_Deleting || DtorType == Dtor_Complete); |
| |
| GlobalDecl GD(Dtor, DtorType); |
| const CGFunctionInfo *FInfo = |
| &CGM.getTypes().arrangeCXXStructorDeclaration(GD); |
| llvm::FunctionType *Ty = CGF.CGM.getTypes().GetFunctionType(*FInfo); |
| CGCallee Callee = CGCallee::forVirtual(CE, GD, This, Ty); |
| |
| QualType ThisTy; |
| if (CE) { |
| ThisTy = CE->getObjectType(); |
| } else { |
| ThisTy = D->getDestroyedType(); |
| } |
| |
| CGF.EmitCXXDestructorCall(GD, Callee, This.getPointer(), ThisTy, nullptr, |
| QualType(), nullptr); |
| return nullptr; |
| } |
| |
| void ItaniumCXXABI::emitVirtualInheritanceTables(const CXXRecordDecl *RD) { |
| CodeGenVTables &VTables = CGM.getVTables(); |
| llvm::GlobalVariable *VTT = VTables.GetAddrOfVTT(RD); |
| VTables.EmitVTTDefinition(VTT, CGM.getVTableLinkage(RD), RD); |
| } |
| |
| bool ItaniumCXXABI::canSpeculativelyEmitVTableAsBaseClass( |
| const CXXRecordDecl *RD) const { |
| // We don't emit available_externally vtables if we are in -fapple-kext mode |
| // because kext mode does not permit devirtualization. |
| if (CGM.getLangOpts().AppleKext) |
| return false; |
| |
| // If the vtable is hidden then it is not safe to emit an available_externally |
| // copy of vtable. |
| if (isVTableHidden(RD)) |
| return false; |
| |
| if (CGM.getCodeGenOpts().ForceEmitVTables) |
| return true; |
| |
| // If we don't have any not emitted inline virtual function then we are safe |
| // to emit an available_externally copy of vtable. |
| // FIXME we can still emit a copy of the vtable if we |
| // can emit definition of the inline functions. |
| if (hasAnyUnusedVirtualInlineFunction(RD)) |
| return false; |
| |
| // For a class with virtual bases, we must also be able to speculatively |
| // emit the VTT, because CodeGen doesn't have separate notions of "can emit |
| // the vtable" and "can emit the VTT". For a base subobject, this means we |
| // need to be able to emit non-virtual base vtables. |
| if (RD->getNumVBases()) { |
| for (const auto &B : RD->bases()) { |
| auto *BRD = B.getType()->getAsCXXRecordDecl(); |
| assert(BRD && "no class for base specifier"); |
| if (B.isVirtual() || !BRD->isDynamicClass()) |
| continue; |
| if (!canSpeculativelyEmitVTableAsBaseClass(BRD)) |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| bool ItaniumCXXABI::canSpeculativelyEmitVTable(const CXXRecordDecl *RD) const { |
| if (!canSpeculativelyEmitVTableAsBaseClass(RD)) |
| return false; |
| |
| // For a complete-object vtable (or more specifically, for the VTT), we need |
| // to be able to speculatively emit the vtables of all dynamic virtual bases. |
| for (const auto &B : RD->vbases()) { |
| auto *BRD = B.getType()->getAsCXXRecordDecl(); |
| assert(BRD && "no class for base specifier"); |
| if (!BRD->isDynamicClass()) |
| continue; |
| if (!canSpeculativelyEmitVTableAsBaseClass(BRD)) |
| return false; |
| } |
| |
| return true; |
| } |
| static llvm::Value *performTypeAdjustment(CodeGenFunction &CGF, |
| Address InitialPtr, |
| int64_t NonVirtualAdjustment, |
| int64_t VirtualAdjustment, |
| bool IsReturnAdjustment) { |
| if (!NonVirtualAdjustment && !VirtualAdjustment) |
| return InitialPtr.getPointer(); |
| |
| Address V = CGF.Builder.CreateElementBitCast(InitialPtr, CGF.Int8Ty); |
| |
| // In a base-to-derived cast, the non-virtual adjustment is applied first. |
| if (NonVirtualAdjustment && !IsReturnAdjustment) { |
| V = CGF.Builder.CreateConstInBoundsByteGEP(V, |
| CharUnits::fromQuantity(NonVirtualAdjustment)); |
| } |
| |
| // Perform the virtual adjustment if we have one. |
| llvm::Value *ResultPtr; |
| if (VirtualAdjustment) { |
| Address VTablePtrPtr = CGF.Builder.CreateElementBitCast(V, CGF.Int8PtrTy); |
| llvm::Value *VTablePtr = CGF.Builder.CreateLoad(VTablePtrPtr); |
| |
| llvm::Value *Offset; |
| llvm::Value *OffsetPtr = |
| CGF.Builder.CreateConstInBoundsGEP1_64(VTablePtr, VirtualAdjustment); |
| if (CGF.CGM.getItaniumVTableContext().isRelativeLayout()) { |
| // Load the adjustment offset from the vtable as a 32-bit int. |
| OffsetPtr = |
| CGF.Builder.CreateBitCast(OffsetPtr, CGF.Int32Ty->getPointerTo()); |
| Offset = |
| CGF.Builder.CreateAlignedLoad(OffsetPtr, CharUnits::fromQuantity(4)); |
| } else { |
| llvm::Type *PtrDiffTy = |
| CGF.ConvertType(CGF.getContext().getPointerDiffType()); |
| |
| OffsetPtr = |
| CGF.Builder.CreateBitCast(OffsetPtr, PtrDiffTy->getPointerTo()); |
| |
| // Load the adjustment offset from the vtable. |
| Offset = CGF.Builder.CreateAlignedLoad(OffsetPtr, CGF.getPointerAlign()); |
| } |
| // Adjust our pointer. |
| ResultPtr = CGF.Builder.CreateInBoundsGEP(V.getPointer(), Offset); |
| } else { |
| ResultPtr = V.getPointer(); |
| } |
| |
| // In a derived-to-base conversion, the non-virtual adjustment is |
| // applied second. |
| if (NonVirtualAdjustment && IsReturnAdjustment) { |
| ResultPtr = CGF.Builder.CreateConstInBoundsGEP1_64(ResultPtr, |
| NonVirtualAdjustment); |
| } |
| |
| // Cast back to the original type. |
| return CGF.Builder.CreateBitCast(ResultPtr, InitialPtr.getType()); |
| } |
| |
| llvm::Value *ItaniumCXXABI::performThisAdjustment(CodeGenFunction &CGF, |
| Address This, |
| const ThisAdjustment &TA) { |
| return performTypeAdjustment(CGF, This, TA.NonVirtual, |
| TA.Virtual.Itanium.VCallOffsetOffset, |
| /*IsReturnAdjustment=*/false); |
| } |
| |
| llvm::Value * |
| ItaniumCXXABI::performReturnAdjustment(CodeGenFunction &CGF, Address Ret, |
| const ReturnAdjustment &RA) { |
| return performTypeAdjustment(CGF, Ret, RA.NonVirtual, |
| RA.Virtual.Itanium.VBaseOffsetOffset, |
| /*IsReturnAdjustment=*/true); |
| } |
| |
| void ARMCXXABI::EmitReturnFromThunk(CodeGenFunction &CGF, |
| RValue RV, QualType ResultType) { |
| if (!isa<CXXDestructorDecl>(CGF.CurGD.getDecl())) |
| return ItaniumCXXABI::EmitReturnFromThunk(CGF, RV, ResultType); |
| |
| // Destructor thunks in the ARM ABI have indeterminate results. |
| llvm::Type *T = CGF.ReturnValue.getElementType(); |
| RValue Undef = RValue::get(llvm::UndefValue::get(T)); |
| return ItaniumCXXABI::EmitReturnFromThunk(CGF, Undef, ResultType); |
| } |
| |
| /************************** Array allocation cookies **************************/ |
| |
| CharUnits ItaniumCXXABI::getArrayCookieSizeImpl(QualType elementType) { |
| // The array cookie is a size_t; pad that up to the element alignment. |
| // The cookie is actually right-justified in that space. |
| return std::max(CharUnits::fromQuantity(CGM.SizeSizeInBytes), |
| CGM.getContext().getTypeAlignInChars(elementType)); |
| } |
| |
| Address ItaniumCXXABI::InitializeArrayCookie(CodeGenFunction &CGF, |
| Address NewPtr, |
| llvm::Value *NumElements, |
| const CXXNewExpr *expr, |
| QualType ElementType) { |
| assert(requiresArrayCookie(expr)); |
| |
| unsigned AS = NewPtr.getAddressSpace(); |
| |
| ASTContext &Ctx = getContext(); |
| CharUnits SizeSize = CGF.getSizeSize(); |
| |
| // The size of the cookie. |
| CharUnits CookieSize = |
| std::max(SizeSize, Ctx.getTypeAlignInChars(ElementType)); |
| assert(CookieSize == getArrayCookieSizeImpl(ElementType)); |
| |
| // Compute an offset to the cookie. |
| Address CookiePtr = NewPtr; |
| CharUnits CookieOffset = CookieSize - SizeSize; |
| if (!CookieOffset.isZero()) |
| CookiePtr = CGF.Builder.CreateConstInBoundsByteGEP(CookiePtr, CookieOffset); |
| |
| // Write the number of elements into the appropriate slot. |
| Address NumElementsPtr = |
| CGF.Builder.CreateElementBitCast(CookiePtr, CGF.SizeTy); |
| llvm::Instruction *SI = CGF.Builder.CreateStore(NumElements, NumElementsPtr); |
| |
| // Handle the array cookie specially in ASan. |
| if (CGM.getLangOpts().Sanitize.has(SanitizerKind::Address) && AS == 0 && |
| (expr->getOperatorNew()->isReplaceableGlobalAllocationFunction() || |
| CGM.getCodeGenOpts().SanitizeAddressPoisonCustomArrayCookie)) { |
| // The store to the CookiePtr does not need to be instrumented. |
| CGM.getSanitizerMetadata()->disableSanitizerForInstruction(SI); |
| llvm::FunctionType *FTy = |
| llvm::FunctionType::get(CGM.VoidTy, NumElementsPtr.getType(), false); |
| llvm::FunctionCallee F = |
| CGM.CreateRuntimeFunction(FTy, "__asan_poison_cxx_array_cookie"); |
| CGF.Builder.CreateCall(F, NumElementsPtr.getPointer()); |
| } |
| |
| // Finally, compute a pointer to the actual data buffer by skipping |
| // over the cookie completely. |
| return CGF.Builder.CreateConstInBoundsByteGEP(NewPtr, CookieSize); |
| } |
| |
| llvm::Value *ItaniumCXXABI::readArrayCookieImpl(CodeGenFunction &CGF, |
| Address allocPtr, |
| CharUnits cookieSize) { |
| // The element size is right-justified in the cookie. |
| Address numElementsPtr = allocPtr; |
| CharUnits numElementsOffset = cookieSize - CGF.getSizeSize(); |
| if (!numElementsOffset.isZero()) |
| numElementsPtr = |
| CGF.Builder.CreateConstInBoundsByteGEP(numElementsPtr, numElementsOffset); |
| |
| unsigned AS = allocPtr.getAddressSpace(); |
| numElementsPtr = CGF.Builder.CreateElementBitCast(numElementsPtr, CGF.SizeTy); |
| if (!CGM.getLangOpts().Sanitize.has(SanitizerKind::Address) || AS != 0) |
| return CGF.Builder.CreateLoad(numElementsPtr); |
| // In asan mode emit a function call instead of a regular load and let the |
| // run-time deal with it: if the shadow is properly poisoned return the |
| // cookie, otherwise return 0 to avoid an infinite loop calling DTORs. |
| // We can't simply ignore this load using nosanitize metadata because |
| // the metadata may be lost. |
| llvm::FunctionType *FTy = |
| llvm::FunctionType::get(CGF.SizeTy, CGF.SizeTy->getPointerTo(0), false); |
| llvm::FunctionCallee F = |
| CGM.CreateRuntimeFunction(FTy, "__asan_load_cxx_array_cookie"); |
| return CGF.Builder.CreateCall(F, numElementsPtr.getPointer()); |
| } |
| |
| CharUnits ARMCXXABI::getArrayCookieSizeImpl(QualType elementType) { |
| // ARM says that the cookie is always: |
| // struct array_cookie { |
| // std::size_t element_size; // element_size != 0 |
| // std::size_t element_count; |
| // }; |
| // But the base ABI doesn't give anything an alignment greater than |
| // 8, so we can dismiss this as typical ABI-author blindness to |
| // actual language complexity and round up to the element alignment. |
| return std::max(CharUnits::fromQuantity(2 * CGM.SizeSizeInBytes), |
| CGM.getContext().getTypeAlignInChars(elementType)); |
| } |
| |
| Address ARMCXXABI::InitializeArrayCookie(CodeGenFunction &CGF, |
| Address newPtr, |
| llvm::Value *numElements, |
| const CXXNewExpr *expr, |
| QualType elementType) { |
| assert(requiresArrayCookie(expr)); |
| |
| // The cookie is always at the start of the buffer. |
| Address cookie = newPtr; |
| |
| // The first element is the element size. |
| cookie = CGF.Builder.CreateElementBitCast(cookie, CGF.SizeTy); |
| llvm::Value *elementSize = llvm::ConstantInt::get(CGF.SizeTy, |
| getContext().getTypeSizeInChars(elementType).getQuantity()); |
| CGF.Builder.CreateStore(elementSize, cookie); |
| |
| // The second element is the element count. |
| cookie = CGF.Builder.CreateConstInBoundsGEP(cookie, 1); |
| CGF.Builder.CreateStore(numElements, cookie); |
| |
| // Finally, compute a pointer to the actual data buffer by skipping |
| // over the cookie completely. |
| CharUnits cookieSize = ARMCXXABI::getArrayCookieSizeImpl(elementType); |
| return CGF.Builder.CreateConstInBoundsByteGEP(newPtr, cookieSize); |
| } |
| |
| llvm::Value *ARMCXXABI::readArrayCookieImpl(CodeGenFunction &CGF, |
| Address allocPtr, |
| CharUnits cookieSize) { |
| // The number of elements is at offset sizeof(size_t) relative to |
| // the allocated pointer. |
| Address numElementsPtr |
| = CGF.Builder.CreateConstInBoundsByteGEP(allocPtr, CGF.getSizeSize()); |
| |
| numElementsPtr = CGF.Builder.CreateElementBitCast(numElementsPtr, CGF.SizeTy); |
| return CGF.Builder.CreateLoad(numElementsPtr); |
| } |
| |
| /*********************** Static local initialization **************************/ |
| |
| static llvm::FunctionCallee getGuardAcquireFn(CodeGenModule &CGM, |
| llvm::PointerType *GuardPtrTy) { |
| // int __cxa_guard_acquire(__guard *guard_object); |
| llvm::FunctionType *FTy = |
| llvm::FunctionType::get(CGM.getTypes().ConvertType(CGM.getContext().IntTy), |
| GuardPtrTy, /*isVarArg=*/false); |
| return CGM.CreateRuntimeFunction( |
| FTy, "__cxa_guard_acquire", |
| llvm::AttributeList::get(CGM.getLLVMContext(), |
| llvm::AttributeList::FunctionIndex, |
| llvm::Attribute::NoUnwind)); |
| } |
| |
| static llvm::FunctionCallee getGuardReleaseFn(CodeGenModule &CGM, |
| llvm::PointerType *GuardPtrTy) { |
| // void __cxa_guard_release(__guard *guard_object); |
| llvm::FunctionType *FTy = |
| llvm::FunctionType::get(CGM.VoidTy, GuardPtrTy, /*isVarArg=*/false); |
| return CGM.CreateRuntimeFunction( |
| FTy, "__cxa_guard_release", |
| llvm::AttributeList::get(CGM.getLLVMContext(), |
| llvm::AttributeList::FunctionIndex, |
| llvm::Attribute::NoUnwind)); |
| } |
| |
| static llvm::FunctionCallee getGuardAbortFn(CodeGenModule &CGM, |
| llvm::PointerType *GuardPtrTy) { |
| // void __cxa_guard_abort(__guard *guard_object); |
| llvm::FunctionType *FTy = |
| llvm::FunctionType::get(CGM.VoidTy, GuardPtrTy, /*isVarArg=*/false); |
| return CGM.CreateRuntimeFunction( |
| FTy, "__cxa_guard_abort", |
| llvm::AttributeList::get(CGM.getLLVMContext(), |
| llvm::AttributeList::FunctionIndex, |
| llvm::Attribute::NoUnwind)); |
| } |
| |
| namespace { |
| struct CallGuardAbort final : EHScopeStack::Cleanup { |
| llvm::GlobalVariable *Guard; |
| CallGuardAbort(llvm::GlobalVariable *Guard) : Guard(Guard) {} |
| |
| void Emit(CodeGenFunction &CGF, Flags flags) override { |
| CGF.EmitNounwindRuntimeCall(getGuardAbortFn(CGF.CGM, Guard->getType()), |
| Guard); |
| } |
| }; |
| } |
| |
| /// The ARM code here follows the Itanium code closely enough that we |
| /// just special-case it at particular places. |
| void ItaniumCXXABI::EmitGuardedInit(CodeGenFunction &CGF, |
| const VarDecl &D, |
| llvm::GlobalVariable *var, |
| bool shouldPerformInit) { |
| CGBuilderTy &Builder = CGF.Builder; |
| |
| // Inline variables that weren't instantiated from variable templates have |
| // partially-ordered initialization within their translation unit. |
| bool NonTemplateInline = |
| D.isInline() && |
| !isTemplateInstantiation(D.getTemplateSpecializationKind()); |
| |
| // We only need to use thread-safe statics for local non-TLS variables and |
| // inline variables; other global initialization is always single-threaded |
| // or (through lazy dynamic loading in multiple threads) unsequenced. |
| bool threadsafe = getContext().getLangOpts().ThreadsafeStatics && |
| (D.isLocalVarDecl() || NonTemplateInline) && |
| !D.getTLSKind(); |
| |
| // If we have a global variable with internal linkage and thread-safe statics |
| // are disabled, we can just let the guard variable be of type i8. |
| bool useInt8GuardVariable = !threadsafe && var->hasInternalLinkage(); |
| |
| llvm::IntegerType *guardTy; |
| CharUnits guardAlignment; |
| if (useInt8GuardVariable) { |
| guardTy = CGF.Int8Ty; |
| guardAlignment = CharUnits::One(); |
| } else { |
| // Guard variables are 64 bits in the generic ABI and size width on ARM |
| // (i.e. 32-bit on AArch32, 64-bit on AArch64). |
| if (UseARMGuardVarABI) { |
| guardTy = CGF.SizeTy; |
| guardAlignment = CGF.getSizeAlign(); |
| } else { |
| guardTy = CGF.Int64Ty; |
| guardAlignment = CharUnits::fromQuantity( |
| CGM.getDataLayout().getABITypeAlignment(guardTy)); |
| } |
| } |
| llvm::PointerType *guardPtrTy = guardTy->getPointerTo(); |
| |
| // Create the guard variable if we don't already have it (as we |
| // might if we're double-emitting this function body). |
| llvm::GlobalVariable *guard = CGM.getStaticLocalDeclGuardAddress(&D); |
| if (!guard) { |
| // Mangle the name for the guard. |
| SmallString<256> guardName; |
| { |
| llvm::raw_svector_ostream out(guardName); |
| getMangleContext().mangleStaticGuardVariable(&D, out); |
| } |
| |
| // Create the guard variable with a zero-initializer. |
| // Just absorb linkage and visibility from the guarded variable. |
| guard = new llvm::GlobalVariable(CGM.getModule(), guardTy, |
| false, var->getLinkage(), |
| llvm::ConstantInt::get(guardTy, 0), |
| guardName.str()); |
| guard->setDSOLocal(var->isDSOLocal()); |
| guard->setVisibility(var->getVisibility()); |
| // If the variable is thread-local, so is its guard variable. |
| guard->setThreadLocalMode(var->getThreadLocalMode()); |
| guard->setAlignment(guardAlignment.getAsAlign()); |
| |
| // The ABI says: "It is suggested that it be emitted in the same COMDAT |
| // group as the associated data object." In practice, this doesn't work for |
| // non-ELF and non-Wasm object formats, so only do it for ELF and Wasm. |
| llvm::Comdat *C = var->getComdat(); |
| if (!D.isLocalVarDecl() && C && |
| (CGM.getTarget().getTriple().isOSBinFormatELF() || |
| CGM.getTarget().getTriple().isOSBinFormatWasm())) { |
| guard->setComdat(C); |
| // An inline variable's guard function is run from the per-TU |
| // initialization function, not via a dedicated global ctor function, so |
| // we can't put it in a comdat. |
| if (!NonTemplateInline) |
| CGF.CurFn->setComdat(C); |
| } else if (CGM.supportsCOMDAT() && guard->isWeakForLinker()) { |
| guard->setComdat(CGM.getModule().getOrInsertComdat(guard->getName())); |
| } |
| |
| CGM.setStaticLocalDeclGuardAddress(&D, guard); |
| } |
| |
| Address guardAddr = Address(guard, guardAlignment); |
| |
| // Test whether the variable has completed initialization. |
| // |
| // Itanium C++ ABI 3.3.2: |
| // The following is pseudo-code showing how these functions can be used: |
| // if (obj_guard.first_byte == 0) { |
| // if ( __cxa_guard_acquire (&obj_guard) ) { |
| // try { |
| // ... initialize the object ...; |
| // } catch (...) { |
| // __cxa_guard_abort (&obj_guard); |
| // throw; |
| // } |
| // ... queue object destructor with __cxa_atexit() ...; |
| // __cxa_guard_release (&obj_guard); |
| // } |
| // } |
| |
| // Load the first byte of the guard variable. |
| llvm::LoadInst *LI = |
| Builder.CreateLoad(Builder.CreateElementBitCast(guardAddr, CGM.Int8Ty)); |
| |
| // Itanium ABI: |
| // An implementation supporting thread-safety on multiprocessor |
| // systems must also guarantee that references to the initialized |
| // object do not occur before the load of the initialization flag. |
| // |
| // In LLVM, we do this by marking the load Acquire. |
| if (threadsafe) |
| LI->setAtomic(llvm::AtomicOrdering::Acquire); |
| |
| // For ARM, we should only check the first bit, rather than the entire byte: |
| // |
| // ARM C++ ABI 3.2.3.1: |
| // To support the potential use of initialization guard variables |
| // as semaphores that are the target of ARM SWP and LDREX/STREX |
| // synchronizing instructions we define a static initialization |
| // guard variable to be a 4-byte aligned, 4-byte word with the |
| // following inline access protocol. |
| // #define INITIALIZED 1 |
| // if ((obj_guard & INITIALIZED) != INITIALIZED) { |
| // if (__cxa_guard_acquire(&obj_guard)) |
| // ... |
| // } |
| // |
| // and similarly for ARM64: |
| // |
| // ARM64 C++ ABI 3.2.2: |
| // This ABI instead only specifies the value bit 0 of the static guard |
| // variable; all other bits are platform defined. Bit 0 shall be 0 when the |
| // variable is not initialized and 1 when it is. |
| llvm::Value *V = |
| (UseARMGuardVarABI && !useInt8GuardVariable) |
| ? Builder.CreateAnd(LI, llvm::ConstantInt::get(CGM.Int8Ty, 1)) |
| : LI; |
| llvm::Value *NeedsInit = Builder.CreateIsNull(V, "guard.uninitialized"); |
| |
| llvm::BasicBlock *InitCheckBlock = CGF.createBasicBlock("init.check"); |
| llvm::BasicBlock *EndBlock = CGF.createBasicBlock("init.end"); |
| |
| // Check if the first byte of the guard variable is zero. |
| CGF.EmitCXXGuardedInitBranch(NeedsInit, InitCheckBlock, EndBlock, |
| CodeGenFunction::GuardKind::VariableGuard, &D); |
| |
| CGF.EmitBlock(InitCheckBlock); |
| |
| // Variables used when coping with thread-safe statics and exceptions. |
| if (threadsafe) { |
| // Call __cxa_guard_acquire. |
| llvm::Value *V |
| = CGF.EmitNounwindRuntimeCall(getGuardAcquireFn(CGM, guardPtrTy), guard); |
| |
| llvm::BasicBlock *InitBlock = CGF.createBasicBlock("init"); |
| |
| Builder.CreateCondBr(Builder.CreateIsNotNull(V, "tobool"), |
| InitBlock, EndBlock); |
| |
| // Call __cxa_guard_abort along the exceptional edge. |
| CGF.EHStack.pushCleanup<CallGuardAbort>(EHCleanup, guard); |
| |
| CGF.EmitBlock(InitBlock); |
| } |
| |
| // Emit the initializer and add a global destructor if appropriate. |
| CGF.EmitCXXGlobalVarDeclInit(D, var, shouldPerformInit); |
| |
| if (threadsafe) { |
| // Pop the guard-abort cleanup if we pushed one. |
| CGF.PopCleanupBlock(); |
| |
| // Call __cxa_guard_release. This cannot throw. |
| CGF.EmitNounwindRuntimeCall(getGuardReleaseFn(CGM, guardPtrTy), |
| guardAddr.getPointer()); |
| } else { |
| Builder.CreateStore(llvm::ConstantInt::get(guardTy, 1), guardAddr); |
| } |
| |
| CGF.EmitBlock(EndBlock); |
| } |
| |
| /// Register a global destructor using __cxa_atexit. |
| static void emitGlobalDtorWithCXAAtExit(CodeGenFunction &CGF, |
| llvm::FunctionCallee dtor, |
| llvm::Constant *addr, bool TLS) { |
| assert((TLS || CGF.getTypes().getCodeGenOpts().CXAAtExit) && |
| "__cxa_atexit is disabled"); |
| const char *Name = "__cxa_atexit"; |
| if (TLS) { |
| const llvm::Triple &T = CGF.getTarget().getTriple(); |
| Name = T.isOSDarwin() ? "_tlv_atexit" : "__cxa_thread_atexit"; |
| } |
| |
| // We're assuming that the destructor function is something we can |
| // reasonably call with the default CC. Go ahead and cast it to the |
| // right prototype. |
| llvm::Type *dtorTy = |
| llvm::FunctionType::get(CGF.VoidTy, CGF.Int8PtrTy, false)->getPointerTo(); |
| |
| // Preserve address space of addr. |
| auto AddrAS = addr ? addr->getType()->getPointerAddressSpace() : 0; |
| auto AddrInt8PtrTy = |
| AddrAS ? CGF.Int8Ty->getPointerTo(AddrAS) : CGF.Int8PtrTy; |
| |
| // Create a variable that binds the atexit to this shared object. |
| llvm::Constant *handle = |
| CGF.CGM.CreateRuntimeVariable(CGF.Int8Ty, "__dso_handle"); |
| auto *GV = cast<llvm::GlobalValue>(handle->stripPointerCasts()); |
| GV->setVisibility(llvm::GlobalValue::HiddenVisibility); |
| |
| // extern "C" int __cxa_atexit(void (*f)(void *), void *p, void *d); |
| llvm::Type *paramTys[] = {dtorTy, AddrInt8PtrTy, handle->getType()}; |
| llvm::FunctionType *atexitTy = |
| llvm::FunctionType::get(CGF.IntTy, paramTys, false); |
| |
| // Fetch the actual function. |
| llvm::FunctionCallee atexit = CGF.CGM.CreateRuntimeFunction(atexitTy, Name); |
| if (llvm::Function *fn = dyn_cast<llvm::Function>(atexit.getCallee())) |
| fn->setDoesNotThrow(); |
| |
| if (!addr) |
| // addr is null when we are trying to register a dtor annotated with |
| // __attribute__((destructor)) in a constructor function. Using null here is |
| // okay because this argument is just passed back to the destructor |
| // function. |
| addr = llvm::Constant::getNullValue(CGF.Int8PtrTy); |
| |
| llvm::Value *args[] = {llvm::ConstantExpr::getBitCast( |
| cast<llvm::Constant>(dtor.getCallee()), dtorTy), |
| llvm::ConstantExpr::getBitCast(addr, AddrInt8PtrTy), |
| handle}; |
| CGF.EmitNounwindRuntimeCall(atexit, args); |
| } |
| |
| void CodeGenModule::registerGlobalDtorsWithAtExit() { |
| for (const auto &I : DtorsUsingAtExit) { |
| int Priority = I.first; |
| const llvm::TinyPtrVector<llvm::Function *> &Dtors = I.second; |
| |
| // Create a function that registers destructors that have the same priority. |
| // |
| // Since constructor functions are run in non-descending order of their |
| // priorities, destructors are registered in non-descending order of their |
| // priorities, and since destructor functions are run in the reverse order |
| // of their registration, destructor functions are run in non-ascending |
| // order of their priorities. |
| CodeGenFunction CGF(*this); |
| std::string GlobalInitFnName = |
| std::string("__GLOBAL_init_") + llvm::to_string(Priority); |
| llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false); |
| llvm::Function *GlobalInitFn = CreateGlobalInitOrCleanUpFunction( |
| FTy, GlobalInitFnName, getTypes().arrangeNullaryFunction(), |
| SourceLocation()); |
| ASTContext &Ctx = getContext(); |
| QualType ReturnTy = Ctx.VoidTy; |
| QualType FunctionTy = Ctx.getFunctionType(ReturnTy, llvm::None, {}); |
| FunctionDecl *FD = FunctionDecl::Create( |
| Ctx, Ctx.getTranslationUnitDecl(), SourceLocation(), SourceLocation(), |
| &Ctx.Idents.get(GlobalInitFnName), FunctionTy, nullptr, SC_Static, |
| false, false); |
| CGF.StartFunction(GlobalDecl(FD), ReturnTy, GlobalInitFn, |
| getTypes().arrangeNullaryFunction(), FunctionArgList(), |
| SourceLocation(), SourceLocation()); |
| |
| for (auto *Dtor : Dtors) { |
| // Register the destructor function calling __cxa_atexit if it is |
| // available. Otherwise fall back on calling atexit. |
| if (getCodeGenOpts().CXAAtExit) |
| emitGlobalDtorWithCXAAtExit(CGF, Dtor, nullptr, false); |
| else |
| CGF.registerGlobalDtorWithAtExit(Dtor); |
| } |
| |
| CGF.FinishFunction(); |
| AddGlobalCtor(GlobalInitFn, Priority, nullptr); |
| } |
| } |
| |
| /// Register a global destructor as best as we know how. |
| void ItaniumCXXABI::registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D, |
| llvm::FunctionCallee dtor, |
| llvm::Constant *addr) { |
| if (D.isNoDestroy(CGM.getContext())) |
| return; |
| |
| // emitGlobalDtorWithCXAAtExit will emit a call to either __cxa_thread_atexit |
| // or __cxa_atexit depending on whether this VarDecl is a thread-local storage |
| // or not. CXAAtExit controls only __cxa_atexit, so use it if it is enabled. |
| // We can always use __cxa_thread_atexit. |
| if (CGM.getCodeGenOpts().CXAAtExit || D.getTLSKind()) |
| return emitGlobalDtorWithCXAAtExit(CGF, dtor, addr, D.getTLSKind()); |
| |
| // In Apple kexts, we want to add a global destructor entry. |
| // FIXME: shouldn't this be guarded by some variable? |
| if (CGM.getLangOpts().AppleKext) { |
| // Generate a global destructor entry. |
| return CGM.AddCXXDtorEntry(dtor, addr); |
| } |
| |
| CGF.registerGlobalDtorWithAtExit(D, dtor, addr); |
| } |
| |
| static bool isThreadWrapperReplaceable(const VarDecl *VD, |
| CodeGen::CodeGenModule &CGM) { |
| assert(!VD->isStaticLocal() && "static local VarDecls don't need wrappers!"); |
| // Darwin prefers to have references to thread local variables to go through |
| // the thread wrapper instead of directly referencing the backing variable. |
| return VD->getTLSKind() == VarDecl::TLS_Dynamic && |
| CGM.getTarget().getTriple().isOSDarwin(); |
| } |
| |
| /// Get the appropriate linkage for the wrapper function. This is essentially |
| /// the weak form of the variable's linkage; every translation unit which needs |
| /// the wrapper emits a copy, and we want the linker to merge them. |
| static llvm::GlobalValue::LinkageTypes |
| getThreadLocalWrapperLinkage(const VarDecl *VD, CodeGen::CodeGenModule &CGM) { |
| llvm::GlobalValue::LinkageTypes VarLinkage = |
| CGM.getLLVMLinkageVarDefinition(VD, /*IsConstant=*/false); |
| |
| // For internal linkage variables, we don't need an external or weak wrapper. |
| if (llvm::GlobalValue::isLocalLinkage(VarLinkage)) |
| return VarLinkage; |
| |
| // If the thread wrapper is replaceable, give it appropriate linkage. |
| if (isThreadWrapperReplaceable(VD, CGM)) |
| if (!llvm::GlobalVariable::isLinkOnceLinkage(VarLinkage) && |
| !llvm::GlobalVariable::isWeakODRLinkage(VarLinkage)) |
| return VarLinkage; |
| return llvm::GlobalValue::WeakODRLinkage; |
| } |
| |
| llvm::Function * |
| ItaniumCXXABI::getOrCreateThreadLocalWrapper(const VarDecl *VD, |
| llvm::Value *Val) { |
| // Mangle the name for the thread_local wrapper function. |
| SmallString<256> WrapperName; |
| { |
| llvm::raw_svector_ostream Out(WrapperName); |
| getMangleContext().mangleItaniumThreadLocalWrapper(VD, Out); |
| } |
| |
| // FIXME: If VD is a definition, we should regenerate the function attributes |
| // before returning. |
| if (llvm::Value *V = CGM.getModule().getNamedValue(WrapperName)) |
| return cast<llvm::Function>(V); |
| |
| QualType RetQT = VD->getType(); |
| if (RetQT->isReferenceType()) |
| RetQT = RetQT.getNonReferenceType(); |
| |
| const CGFunctionInfo &FI = CGM.getTypes().arrangeBuiltinFunctionDeclaration( |
| getContext().getPointerType(RetQT), FunctionArgList()); |
| |
| llvm::FunctionType *FnTy = CGM.getTypes().GetFunctionType(FI); |
| llvm::Function *Wrapper = |
| llvm::Function::Create(FnTy, getThreadLocalWrapperLinkage(VD, CGM), |
| WrapperName.str(), &CGM.getModule()); |
| |
| if (CGM.supportsCOMDAT() && Wrapper->isWeakForLinker()) |
| Wrapper->setComdat(CGM.getModule().getOrInsertComdat(Wrapper->getName())); |
| |
| CGM.SetLLVMFunctionAttributes(GlobalDecl(), FI, Wrapper); |
| |
| // Always resolve references to the wrapper at link time. |
| if (!Wrapper->hasLocalLinkage()) |
| if (!isThreadWrapperReplaceable(VD, CGM) || |
| llvm::GlobalVariable::isLinkOnceLinkage(Wrapper->getLinkage()) || |
| llvm::GlobalVariable::isWeakODRLinkage(Wrapper->getLinkage()) || |
| VD->getVisibility() == HiddenVisibility) |
| Wrapper->setVisibility(llvm::GlobalValue::HiddenVisibility); |
| |
| if (isThreadWrapperReplaceable(VD, CGM)) { |
|