735 lines
26 KiB
C++
735 lines
26 KiB
C++
//===--- CGVTables.cpp - Emit LLVM Code for C++ vtables -------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This contains code dealing with C++ code generation of virtual tables.
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//
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//===----------------------------------------------------------------------===//
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#include "CodeGenModule.h"
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#include "CodeGenFunction.h"
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#include "CGCXXABI.h"
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#include "clang/AST/CXXInheritance.h"
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#include "clang/AST/RecordLayout.h"
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#include "clang/Frontend/CodeGenOptions.h"
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#include "llvm/ADT/DenseSet.h"
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#include "llvm/ADT/SetVector.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/Format.h"
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#include "llvm/Transforms/Utils/Cloning.h"
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#include <algorithm>
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#include <cstdio>
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using namespace clang;
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using namespace CodeGen;
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CodeGenVTables::CodeGenVTables(CodeGenModule &CGM)
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: CGM(CGM), VTContext(CGM.getContext()) { }
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bool CodeGenVTables::ShouldEmitVTableInThisTU(const CXXRecordDecl *RD) {
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assert(RD->isDynamicClass() && "Non dynamic classes have no VTable.");
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TemplateSpecializationKind TSK = RD->getTemplateSpecializationKind();
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if (TSK == TSK_ExplicitInstantiationDeclaration)
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return false;
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const CXXMethodDecl *KeyFunction = CGM.getContext().getKeyFunction(RD);
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if (!KeyFunction)
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return true;
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// Itanium C++ ABI, 5.2.6 Instantiated Templates:
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// An instantiation of a class template requires:
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// - In the object where instantiated, the virtual table...
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if (TSK == TSK_ImplicitInstantiation ||
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TSK == TSK_ExplicitInstantiationDefinition)
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return true;
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// If we're building with optimization, we always emit VTables since that
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// allows for virtual function calls to be devirtualized.
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// (We don't want to do this in -fapple-kext mode however).
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if (CGM.getCodeGenOpts().OptimizationLevel && !CGM.getLangOpts().AppleKext)
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return true;
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return KeyFunction->hasBody();
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}
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llvm::Constant *CodeGenModule::GetAddrOfThunk(GlobalDecl GD,
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const ThunkInfo &Thunk) {
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const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
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// Compute the mangled name.
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SmallString<256> Name;
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llvm::raw_svector_ostream Out(Name);
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if (const CXXDestructorDecl* DD = dyn_cast<CXXDestructorDecl>(MD))
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getCXXABI().getMangleContext().mangleCXXDtorThunk(DD, GD.getDtorType(),
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Thunk.This, Out);
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else
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getCXXABI().getMangleContext().mangleThunk(MD, Thunk, Out);
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Out.flush();
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llvm::Type *Ty = getTypes().GetFunctionTypeForVTable(GD);
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return GetOrCreateLLVMFunction(Name, Ty, GD, /*ForVTable=*/true);
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}
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static llvm::Value *PerformTypeAdjustment(CodeGenFunction &CGF,
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llvm::Value *Ptr,
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int64_t NonVirtualAdjustment,
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int64_t VirtualAdjustment) {
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if (!NonVirtualAdjustment && !VirtualAdjustment)
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return Ptr;
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llvm::Type *Int8PtrTy = CGF.Int8PtrTy;
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llvm::Value *V = CGF.Builder.CreateBitCast(Ptr, Int8PtrTy);
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if (NonVirtualAdjustment) {
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// Do the non-virtual adjustment.
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V = CGF.Builder.CreateConstInBoundsGEP1_64(V, NonVirtualAdjustment);
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}
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if (VirtualAdjustment) {
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llvm::Type *PtrDiffTy =
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CGF.ConvertType(CGF.getContext().getPointerDiffType());
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// Do the virtual adjustment.
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llvm::Value *VTablePtrPtr =
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CGF.Builder.CreateBitCast(V, Int8PtrTy->getPointerTo());
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llvm::Value *VTablePtr = CGF.Builder.CreateLoad(VTablePtrPtr);
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llvm::Value *OffsetPtr =
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CGF.Builder.CreateConstInBoundsGEP1_64(VTablePtr, VirtualAdjustment);
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OffsetPtr = CGF.Builder.CreateBitCast(OffsetPtr, PtrDiffTy->getPointerTo());
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// Load the adjustment offset from the vtable.
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llvm::Value *Offset = CGF.Builder.CreateLoad(OffsetPtr);
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// Adjust our pointer.
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V = CGF.Builder.CreateInBoundsGEP(V, Offset);
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}
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// Cast back to the original type.
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return CGF.Builder.CreateBitCast(V, Ptr->getType());
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}
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static void setThunkVisibility(CodeGenModule &CGM, const CXXMethodDecl *MD,
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const ThunkInfo &Thunk, llvm::Function *Fn) {
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CGM.setGlobalVisibility(Fn, MD);
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if (!CGM.getCodeGenOpts().HiddenWeakVTables)
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return;
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// If the thunk has weak/linkonce linkage, but the function must be
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// emitted in every translation unit that references it, then we can
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// emit its thunks with hidden visibility, since its thunks must be
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// emitted when the function is.
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// This follows CodeGenModule::setTypeVisibility; see the comments
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// there for explanation.
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if ((Fn->getLinkage() != llvm::GlobalVariable::LinkOnceODRLinkage &&
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Fn->getLinkage() != llvm::GlobalVariable::WeakODRLinkage) ||
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Fn->getVisibility() != llvm::GlobalVariable::DefaultVisibility)
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return;
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if (MD->getExplicitVisibility())
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return;
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switch (MD->getTemplateSpecializationKind()) {
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case TSK_ExplicitInstantiationDefinition:
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case TSK_ExplicitInstantiationDeclaration:
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return;
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case TSK_Undeclared:
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break;
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case TSK_ExplicitSpecialization:
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case TSK_ImplicitInstantiation:
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if (!CGM.getCodeGenOpts().HiddenWeakTemplateVTables)
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return;
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break;
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}
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// If there's an explicit definition, and that definition is
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// out-of-line, then we can't assume that all users will have a
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// definition to emit.
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const FunctionDecl *Def = 0;
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if (MD->hasBody(Def) && Def->isOutOfLine())
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return;
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Fn->setVisibility(llvm::GlobalValue::HiddenVisibility);
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}
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#ifndef NDEBUG
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static bool similar(const ABIArgInfo &infoL, CanQualType typeL,
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const ABIArgInfo &infoR, CanQualType typeR) {
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return (infoL.getKind() == infoR.getKind() &&
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(typeL == typeR ||
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(isa<PointerType>(typeL) && isa<PointerType>(typeR)) ||
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(isa<ReferenceType>(typeL) && isa<ReferenceType>(typeR))));
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}
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#endif
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static RValue PerformReturnAdjustment(CodeGenFunction &CGF,
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QualType ResultType, RValue RV,
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const ThunkInfo &Thunk) {
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// Emit the return adjustment.
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bool NullCheckValue = !ResultType->isReferenceType();
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llvm::BasicBlock *AdjustNull = 0;
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llvm::BasicBlock *AdjustNotNull = 0;
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llvm::BasicBlock *AdjustEnd = 0;
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llvm::Value *ReturnValue = RV.getScalarVal();
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if (NullCheckValue) {
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AdjustNull = CGF.createBasicBlock("adjust.null");
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AdjustNotNull = CGF.createBasicBlock("adjust.notnull");
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AdjustEnd = CGF.createBasicBlock("adjust.end");
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llvm::Value *IsNull = CGF.Builder.CreateIsNull(ReturnValue);
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CGF.Builder.CreateCondBr(IsNull, AdjustNull, AdjustNotNull);
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CGF.EmitBlock(AdjustNotNull);
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}
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ReturnValue = PerformTypeAdjustment(CGF, ReturnValue,
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Thunk.Return.NonVirtual,
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Thunk.Return.VBaseOffsetOffset);
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if (NullCheckValue) {
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CGF.Builder.CreateBr(AdjustEnd);
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CGF.EmitBlock(AdjustNull);
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CGF.Builder.CreateBr(AdjustEnd);
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CGF.EmitBlock(AdjustEnd);
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llvm::PHINode *PHI = CGF.Builder.CreatePHI(ReturnValue->getType(), 2);
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PHI->addIncoming(ReturnValue, AdjustNotNull);
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PHI->addIncoming(llvm::Constant::getNullValue(ReturnValue->getType()),
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AdjustNull);
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ReturnValue = PHI;
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}
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return RValue::get(ReturnValue);
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}
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// This function does roughly the same thing as GenerateThunk, but in a
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// very different way, so that va_start and va_end work correctly.
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// FIXME: This function assumes "this" is the first non-sret LLVM argument of
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// a function, and that there is an alloca built in the entry block
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// for all accesses to "this".
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// FIXME: This function assumes there is only one "ret" statement per function.
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// FIXME: Cloning isn't correct in the presence of indirect goto!
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// FIXME: This implementation of thunks bloats codesize by duplicating the
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// function definition. There are alternatives:
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// 1. Add some sort of stub support to LLVM for cases where we can
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// do a this adjustment, then a sibcall.
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// 2. We could transform the definition to take a va_list instead of an
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// actual variable argument list, then have the thunks (including a
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// no-op thunk for the regular definition) call va_start/va_end.
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// There's a bit of per-call overhead for this solution, but it's
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// better for codesize if the definition is long.
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void CodeGenFunction::GenerateVarArgsThunk(
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llvm::Function *Fn,
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const CGFunctionInfo &FnInfo,
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GlobalDecl GD, const ThunkInfo &Thunk) {
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const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
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const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
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QualType ResultType = FPT->getResultType();
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// Get the original function
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assert(FnInfo.isVariadic());
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llvm::Type *Ty = CGM.getTypes().GetFunctionType(FnInfo);
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llvm::Value *Callee = CGM.GetAddrOfFunction(GD, Ty, /*ForVTable=*/true);
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llvm::Function *BaseFn = cast<llvm::Function>(Callee);
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// Clone to thunk.
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llvm::Function *NewFn = llvm::CloneFunction(BaseFn);
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CGM.getModule().getFunctionList().push_back(NewFn);
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Fn->replaceAllUsesWith(NewFn);
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NewFn->takeName(Fn);
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Fn->eraseFromParent();
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Fn = NewFn;
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// "Initialize" CGF (minimally).
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CurFn = Fn;
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// Get the "this" value
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llvm::Function::arg_iterator AI = Fn->arg_begin();
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if (CGM.ReturnTypeUsesSRet(FnInfo))
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++AI;
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// Find the first store of "this", which will be to the alloca associated
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// with "this".
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llvm::Value *ThisPtr = &*AI;
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llvm::BasicBlock *EntryBB = Fn->begin();
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llvm::Instruction *ThisStore = 0;
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for (llvm::BasicBlock::iterator I = EntryBB->begin(), E = EntryBB->end();
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I != E; I++) {
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if (isa<llvm::StoreInst>(I) && I->getOperand(0) == ThisPtr) {
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ThisStore = cast<llvm::StoreInst>(I);
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break;
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}
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}
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assert(ThisStore && "Store of this should be in entry block?");
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// Adjust "this", if necessary.
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Builder.SetInsertPoint(ThisStore);
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llvm::Value *AdjustedThisPtr =
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PerformTypeAdjustment(*this, ThisPtr,
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Thunk.This.NonVirtual,
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Thunk.This.VCallOffsetOffset);
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ThisStore->setOperand(0, AdjustedThisPtr);
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if (!Thunk.Return.isEmpty()) {
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// Fix up the returned value, if necessary.
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for (llvm::Function::iterator I = Fn->begin(), E = Fn->end(); I != E; I++) {
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llvm::Instruction *T = I->getTerminator();
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if (isa<llvm::ReturnInst>(T)) {
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RValue RV = RValue::get(T->getOperand(0));
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T->eraseFromParent();
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Builder.SetInsertPoint(&*I);
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RV = PerformReturnAdjustment(*this, ResultType, RV, Thunk);
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Builder.CreateRet(RV.getScalarVal());
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break;
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}
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}
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}
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}
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void CodeGenFunction::GenerateThunk(llvm::Function *Fn,
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const CGFunctionInfo &FnInfo,
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GlobalDecl GD, const ThunkInfo &Thunk) {
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const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
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const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
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QualType ResultType = FPT->getResultType();
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QualType ThisType = MD->getThisType(getContext());
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FunctionArgList FunctionArgs;
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// FIXME: It would be nice if more of this code could be shared with
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// CodeGenFunction::GenerateCode.
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// Create the implicit 'this' parameter declaration.
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CurGD = GD;
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CGM.getCXXABI().BuildInstanceFunctionParams(*this, ResultType, FunctionArgs);
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// Add the rest of the parameters.
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for (FunctionDecl::param_const_iterator I = MD->param_begin(),
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E = MD->param_end(); I != E; ++I) {
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ParmVarDecl *Param = *I;
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FunctionArgs.push_back(Param);
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}
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StartFunction(GlobalDecl(), ResultType, Fn, FnInfo, FunctionArgs,
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SourceLocation());
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CGM.getCXXABI().EmitInstanceFunctionProlog(*this);
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CXXThisValue = CXXABIThisValue;
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// Adjust the 'this' pointer if necessary.
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llvm::Value *AdjustedThisPtr =
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PerformTypeAdjustment(*this, LoadCXXThis(),
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Thunk.This.NonVirtual,
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Thunk.This.VCallOffsetOffset);
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CallArgList CallArgs;
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// Add our adjusted 'this' pointer.
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CallArgs.add(RValue::get(AdjustedThisPtr), ThisType);
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// Add the rest of the parameters.
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for (FunctionDecl::param_const_iterator I = MD->param_begin(),
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E = MD->param_end(); I != E; ++I) {
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ParmVarDecl *param = *I;
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EmitDelegateCallArg(CallArgs, param);
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}
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// Get our callee.
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llvm::Type *Ty =
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CGM.getTypes().GetFunctionType(CGM.getTypes().arrangeGlobalDeclaration(GD));
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llvm::Value *Callee = CGM.GetAddrOfFunction(GD, Ty, /*ForVTable=*/true);
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#ifndef NDEBUG
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const CGFunctionInfo &CallFnInfo =
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CGM.getTypes().arrangeCXXMethodCall(CallArgs, FPT,
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RequiredArgs::forPrototypePlus(FPT, 1));
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assert(CallFnInfo.getRegParm() == FnInfo.getRegParm() &&
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CallFnInfo.isNoReturn() == FnInfo.isNoReturn() &&
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CallFnInfo.getCallingConvention() == FnInfo.getCallingConvention());
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assert(isa<CXXDestructorDecl>(MD) || // ignore dtor return types
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similar(CallFnInfo.getReturnInfo(), CallFnInfo.getReturnType(),
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FnInfo.getReturnInfo(), FnInfo.getReturnType()));
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assert(CallFnInfo.arg_size() == FnInfo.arg_size());
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for (unsigned i = 0, e = FnInfo.arg_size(); i != e; ++i)
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assert(similar(CallFnInfo.arg_begin()[i].info,
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CallFnInfo.arg_begin()[i].type,
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FnInfo.arg_begin()[i].info, FnInfo.arg_begin()[i].type));
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#endif
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// Determine whether we have a return value slot to use.
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ReturnValueSlot Slot;
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if (!ResultType->isVoidType() &&
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FnInfo.getReturnInfo().getKind() == ABIArgInfo::Indirect &&
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hasAggregateLLVMType(CurFnInfo->getReturnType()))
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Slot = ReturnValueSlot(ReturnValue, ResultType.isVolatileQualified());
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// Now emit our call.
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RValue RV = EmitCall(FnInfo, Callee, Slot, CallArgs, MD);
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if (!Thunk.Return.isEmpty())
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RV = PerformReturnAdjustment(*this, ResultType, RV, Thunk);
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if (!ResultType->isVoidType() && Slot.isNull())
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CGM.getCXXABI().EmitReturnFromThunk(*this, RV, ResultType);
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FinishFunction();
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// Set the right linkage.
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CGM.setFunctionLinkage(MD, Fn);
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// Set the right visibility.
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setThunkVisibility(CGM, MD, Thunk, Fn);
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}
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void CodeGenVTables::EmitThunk(GlobalDecl GD, const ThunkInfo &Thunk,
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bool UseAvailableExternallyLinkage)
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{
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const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeGlobalDeclaration(GD);
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// FIXME: re-use FnInfo in this computation.
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llvm::Constant *Entry = CGM.GetAddrOfThunk(GD, Thunk);
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// Strip off a bitcast if we got one back.
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if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) {
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assert(CE->getOpcode() == llvm::Instruction::BitCast);
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Entry = CE->getOperand(0);
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}
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// There's already a declaration with the same name, check if it has the same
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// type or if we need to replace it.
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if (cast<llvm::GlobalValue>(Entry)->getType()->getElementType() !=
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CGM.getTypes().GetFunctionTypeForVTable(GD)) {
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llvm::GlobalValue *OldThunkFn = cast<llvm::GlobalValue>(Entry);
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// If the types mismatch then we have to rewrite the definition.
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assert(OldThunkFn->isDeclaration() &&
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"Shouldn't replace non-declaration");
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// Remove the name from the old thunk function and get a new thunk.
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OldThunkFn->setName(StringRef());
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Entry = CGM.GetAddrOfThunk(GD, Thunk);
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// If needed, replace the old thunk with a bitcast.
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if (!OldThunkFn->use_empty()) {
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llvm::Constant *NewPtrForOldDecl =
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llvm::ConstantExpr::getBitCast(Entry, OldThunkFn->getType());
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OldThunkFn->replaceAllUsesWith(NewPtrForOldDecl);
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}
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// Remove the old thunk.
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OldThunkFn->eraseFromParent();
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}
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llvm::Function *ThunkFn = cast<llvm::Function>(Entry);
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if (!ThunkFn->isDeclaration()) {
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if (UseAvailableExternallyLinkage) {
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// There is already a thunk emitted for this function, do nothing.
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return;
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}
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// If a function has a body, it should have available_externally linkage.
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assert(ThunkFn->hasAvailableExternallyLinkage() &&
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"Function should have available_externally linkage!");
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// Change the linkage.
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CGM.setFunctionLinkage(cast<CXXMethodDecl>(GD.getDecl()), ThunkFn);
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return;
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}
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if (ThunkFn->isVarArg()) {
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// Varargs thunks are special; we can't just generate a call because
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// we can't copy the varargs. Our implementation is rather
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// expensive/sucky at the moment, so don't generate the thunk unless
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// we have to.
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// FIXME: Do something better here; GenerateVarArgsThunk is extremely ugly.
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if (!UseAvailableExternallyLinkage)
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CodeGenFunction(CGM).GenerateVarArgsThunk(ThunkFn, FnInfo, GD, Thunk);
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} else {
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// Normal thunk body generation.
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CodeGenFunction(CGM).GenerateThunk(ThunkFn, FnInfo, GD, Thunk);
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}
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if (UseAvailableExternallyLinkage)
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ThunkFn->setLinkage(llvm::GlobalValue::AvailableExternallyLinkage);
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}
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void CodeGenVTables::MaybeEmitThunkAvailableExternally(GlobalDecl GD,
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const ThunkInfo &Thunk) {
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// We only want to do this when building with optimizations.
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if (!CGM.getCodeGenOpts().OptimizationLevel)
|
|
return;
|
|
|
|
// We can't emit thunks for member functions with incomplete types.
|
|
const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
|
|
if (!CGM.getTypes().isFuncTypeConvertible(
|
|
cast<FunctionType>(MD->getType().getTypePtr())))
|
|
return;
|
|
|
|
EmitThunk(GD, Thunk, /*UseAvailableExternallyLinkage=*/true);
|
|
}
|
|
|
|
void CodeGenVTables::EmitThunks(GlobalDecl GD)
|
|
{
|
|
const CXXMethodDecl *MD =
|
|
cast<CXXMethodDecl>(GD.getDecl())->getCanonicalDecl();
|
|
|
|
// We don't need to generate thunks for the base destructor.
|
|
if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base)
|
|
return;
|
|
|
|
const VTableContext::ThunkInfoVectorTy *ThunkInfoVector =
|
|
VTContext.getThunkInfo(MD);
|
|
if (!ThunkInfoVector)
|
|
return;
|
|
|
|
for (unsigned I = 0, E = ThunkInfoVector->size(); I != E; ++I)
|
|
EmitThunk(GD, (*ThunkInfoVector)[I],
|
|
/*UseAvailableExternallyLinkage=*/false);
|
|
}
|
|
|
|
llvm::Constant *
|
|
CodeGenVTables::CreateVTableInitializer(const CXXRecordDecl *RD,
|
|
const VTableComponent *Components,
|
|
unsigned NumComponents,
|
|
const VTableLayout::VTableThunkTy *VTableThunks,
|
|
unsigned NumVTableThunks) {
|
|
SmallVector<llvm::Constant *, 64> Inits;
|
|
|
|
llvm::Type *Int8PtrTy = CGM.Int8PtrTy;
|
|
|
|
llvm::Type *PtrDiffTy =
|
|
CGM.getTypes().ConvertType(CGM.getContext().getPointerDiffType());
|
|
|
|
QualType ClassType = CGM.getContext().getTagDeclType(RD);
|
|
llvm::Constant *RTTI = CGM.GetAddrOfRTTIDescriptor(ClassType);
|
|
|
|
unsigned NextVTableThunkIndex = 0;
|
|
|
|
llvm::Constant* PureVirtualFn = 0;
|
|
|
|
for (unsigned I = 0; I != NumComponents; ++I) {
|
|
VTableComponent Component = Components[I];
|
|
|
|
llvm::Constant *Init = 0;
|
|
|
|
switch (Component.getKind()) {
|
|
case VTableComponent::CK_VCallOffset:
|
|
Init = llvm::ConstantInt::get(PtrDiffTy,
|
|
Component.getVCallOffset().getQuantity());
|
|
Init = llvm::ConstantExpr::getIntToPtr(Init, Int8PtrTy);
|
|
break;
|
|
case VTableComponent::CK_VBaseOffset:
|
|
Init = llvm::ConstantInt::get(PtrDiffTy,
|
|
Component.getVBaseOffset().getQuantity());
|
|
Init = llvm::ConstantExpr::getIntToPtr(Init, Int8PtrTy);
|
|
break;
|
|
case VTableComponent::CK_OffsetToTop:
|
|
Init = llvm::ConstantInt::get(PtrDiffTy,
|
|
Component.getOffsetToTop().getQuantity());
|
|
Init = llvm::ConstantExpr::getIntToPtr(Init, Int8PtrTy);
|
|
break;
|
|
case VTableComponent::CK_RTTI:
|
|
Init = llvm::ConstantExpr::getBitCast(RTTI, Int8PtrTy);
|
|
break;
|
|
case VTableComponent::CK_FunctionPointer:
|
|
case VTableComponent::CK_CompleteDtorPointer:
|
|
case VTableComponent::CK_DeletingDtorPointer: {
|
|
GlobalDecl GD;
|
|
|
|
// Get the right global decl.
|
|
switch (Component.getKind()) {
|
|
default:
|
|
llvm_unreachable("Unexpected vtable component kind");
|
|
case VTableComponent::CK_FunctionPointer:
|
|
GD = Component.getFunctionDecl();
|
|
break;
|
|
case VTableComponent::CK_CompleteDtorPointer:
|
|
GD = GlobalDecl(Component.getDestructorDecl(), Dtor_Complete);
|
|
break;
|
|
case VTableComponent::CK_DeletingDtorPointer:
|
|
GD = GlobalDecl(Component.getDestructorDecl(), Dtor_Deleting);
|
|
break;
|
|
}
|
|
|
|
if (cast<CXXMethodDecl>(GD.getDecl())->isPure()) {
|
|
// We have a pure virtual member function.
|
|
if (!PureVirtualFn) {
|
|
llvm::FunctionType *Ty =
|
|
llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
|
|
PureVirtualFn =
|
|
CGM.CreateRuntimeFunction(Ty, "__cxa_pure_virtual");
|
|
PureVirtualFn = llvm::ConstantExpr::getBitCast(PureVirtualFn,
|
|
Int8PtrTy);
|
|
}
|
|
|
|
Init = PureVirtualFn;
|
|
} else {
|
|
// Check if we should use a thunk.
|
|
if (NextVTableThunkIndex < NumVTableThunks &&
|
|
VTableThunks[NextVTableThunkIndex].first == I) {
|
|
const ThunkInfo &Thunk = VTableThunks[NextVTableThunkIndex].second;
|
|
|
|
MaybeEmitThunkAvailableExternally(GD, Thunk);
|
|
Init = CGM.GetAddrOfThunk(GD, Thunk);
|
|
|
|
NextVTableThunkIndex++;
|
|
} else {
|
|
llvm::Type *Ty = CGM.getTypes().GetFunctionTypeForVTable(GD);
|
|
|
|
Init = CGM.GetAddrOfFunction(GD, Ty, /*ForVTable=*/true);
|
|
}
|
|
|
|
Init = llvm::ConstantExpr::getBitCast(Init, Int8PtrTy);
|
|
}
|
|
break;
|
|
}
|
|
|
|
case VTableComponent::CK_UnusedFunctionPointer:
|
|
Init = llvm::ConstantExpr::getNullValue(Int8PtrTy);
|
|
break;
|
|
};
|
|
|
|
Inits.push_back(Init);
|
|
}
|
|
|
|
llvm::ArrayType *ArrayType = llvm::ArrayType::get(Int8PtrTy, NumComponents);
|
|
return llvm::ConstantArray::get(ArrayType, Inits);
|
|
}
|
|
|
|
llvm::GlobalVariable *CodeGenVTables::GetAddrOfVTable(const CXXRecordDecl *RD) {
|
|
llvm::GlobalVariable *&VTable = VTables[RD];
|
|
if (VTable)
|
|
return VTable;
|
|
|
|
// We may need to generate a definition for this vtable.
|
|
if (ShouldEmitVTableInThisTU(RD))
|
|
CGM.DeferredVTables.push_back(RD);
|
|
|
|
SmallString<256> OutName;
|
|
llvm::raw_svector_ostream Out(OutName);
|
|
CGM.getCXXABI().getMangleContext().mangleCXXVTable(RD, Out);
|
|
Out.flush();
|
|
StringRef Name = OutName.str();
|
|
|
|
llvm::ArrayType *ArrayType =
|
|
llvm::ArrayType::get(CGM.Int8PtrTy,
|
|
VTContext.getVTableLayout(RD).getNumVTableComponents());
|
|
|
|
VTable =
|
|
CGM.CreateOrReplaceCXXRuntimeVariable(Name, ArrayType,
|
|
llvm::GlobalValue::ExternalLinkage);
|
|
VTable->setUnnamedAddr(true);
|
|
return VTable;
|
|
}
|
|
|
|
void
|
|
CodeGenVTables::EmitVTableDefinition(llvm::GlobalVariable *VTable,
|
|
llvm::GlobalVariable::LinkageTypes Linkage,
|
|
const CXXRecordDecl *RD) {
|
|
const VTableLayout &VTLayout = VTContext.getVTableLayout(RD);
|
|
|
|
// Create and set the initializer.
|
|
llvm::Constant *Init =
|
|
CreateVTableInitializer(RD,
|
|
VTLayout.vtable_component_begin(),
|
|
VTLayout.getNumVTableComponents(),
|
|
VTLayout.vtable_thunk_begin(),
|
|
VTLayout.getNumVTableThunks());
|
|
VTable->setInitializer(Init);
|
|
|
|
// Set the correct linkage.
|
|
VTable->setLinkage(Linkage);
|
|
|
|
// Set the right visibility.
|
|
CGM.setTypeVisibility(VTable, RD, CodeGenModule::TVK_ForVTable);
|
|
}
|
|
|
|
llvm::GlobalVariable *
|
|
CodeGenVTables::GenerateConstructionVTable(const CXXRecordDecl *RD,
|
|
const BaseSubobject &Base,
|
|
bool BaseIsVirtual,
|
|
llvm::GlobalVariable::LinkageTypes Linkage,
|
|
VTableAddressPointsMapTy& AddressPoints) {
|
|
OwningPtr<VTableLayout> VTLayout(
|
|
VTContext.createConstructionVTableLayout(Base.getBase(),
|
|
Base.getBaseOffset(),
|
|
BaseIsVirtual, RD));
|
|
|
|
// Add the address points.
|
|
AddressPoints = VTLayout->getAddressPoints();
|
|
|
|
// Get the mangled construction vtable name.
|
|
SmallString<256> OutName;
|
|
llvm::raw_svector_ostream Out(OutName);
|
|
CGM.getCXXABI().getMangleContext().
|
|
mangleCXXCtorVTable(RD, Base.getBaseOffset().getQuantity(), Base.getBase(),
|
|
Out);
|
|
Out.flush();
|
|
StringRef Name = OutName.str();
|
|
|
|
llvm::ArrayType *ArrayType =
|
|
llvm::ArrayType::get(CGM.Int8PtrTy, VTLayout->getNumVTableComponents());
|
|
|
|
// Create the variable that will hold the construction vtable.
|
|
llvm::GlobalVariable *VTable =
|
|
CGM.CreateOrReplaceCXXRuntimeVariable(Name, ArrayType, Linkage);
|
|
CGM.setTypeVisibility(VTable, RD, CodeGenModule::TVK_ForConstructionVTable);
|
|
|
|
// V-tables are always unnamed_addr.
|
|
VTable->setUnnamedAddr(true);
|
|
|
|
// Create and set the initializer.
|
|
llvm::Constant *Init =
|
|
CreateVTableInitializer(Base.getBase(),
|
|
VTLayout->vtable_component_begin(),
|
|
VTLayout->getNumVTableComponents(),
|
|
VTLayout->vtable_thunk_begin(),
|
|
VTLayout->getNumVTableThunks());
|
|
VTable->setInitializer(Init);
|
|
|
|
return VTable;
|
|
}
|
|
|
|
void
|
|
CodeGenVTables::GenerateClassData(llvm::GlobalVariable::LinkageTypes Linkage,
|
|
const CXXRecordDecl *RD) {
|
|
llvm::GlobalVariable *VTable = GetAddrOfVTable(RD);
|
|
if (VTable->hasInitializer())
|
|
return;
|
|
|
|
EmitVTableDefinition(VTable, Linkage, RD);
|
|
|
|
if (RD->getNumVBases()) {
|
|
llvm::GlobalVariable *VTT = GetAddrOfVTT(RD);
|
|
EmitVTTDefinition(VTT, Linkage, 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())
|
|
CGM.EmitFundamentalRTTIDescriptors();
|
|
}
|