Move VTable builder to AST
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@140510 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/VTableBuilder.cpp b/lib/AST/VTableBuilder.cpp
new file mode 100644
index 0000000..49032b4
--- /dev/null
+++ b/lib/AST/VTableBuilder.cpp
@@ -0,0 +1,2404 @@
+//===--- VTableBuilder.cpp - C++ vtable layout builder --------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This contains code dealing with generation of the layout of virtual tables.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/AST/VTableBuilder.h"
+#include "clang/AST/CXXInheritance.h"
+#include "clang/AST/RecordLayout.h"
+#include "clang/Basic/TargetInfo.h"
+#include "llvm/Support/Format.h"
+#include <algorithm>
+#include <cstdio>
+
+using namespace clang;
+
+#define DUMP_OVERRIDERS 0
+
+namespace {
+
+/// BaseOffset - Represents an offset from a derived class to a direct or
+/// indirect base class.
+struct BaseOffset {
+ /// DerivedClass - The derived class.
+ const CXXRecordDecl *DerivedClass;
+
+ /// VirtualBase - If the path from the derived class to the base class
+ /// involves a virtual base class, this holds its declaration.
+ const CXXRecordDecl *VirtualBase;
+
+ /// NonVirtualOffset - The offset from the derived class to the base class.
+ /// (Or the offset from the virtual base class to the base class, if the
+ /// path from the derived class to the base class involves a virtual base
+ /// class.
+ CharUnits NonVirtualOffset;
+
+ BaseOffset() : DerivedClass(0), VirtualBase(0),
+ NonVirtualOffset(CharUnits::Zero()) { }
+ BaseOffset(const CXXRecordDecl *DerivedClass,
+ const CXXRecordDecl *VirtualBase, CharUnits NonVirtualOffset)
+ : DerivedClass(DerivedClass), VirtualBase(VirtualBase),
+ NonVirtualOffset(NonVirtualOffset) { }
+
+ bool isEmpty() const { return NonVirtualOffset.isZero() && !VirtualBase; }
+};
+
+/// FinalOverriders - Contains the final overrider member functions for all
+/// member functions in the base subobjects of a class.
+class FinalOverriders {
+public:
+ /// OverriderInfo - Information about a final overrider.
+ struct OverriderInfo {
+ /// Method - The method decl of the overrider.
+ const CXXMethodDecl *Method;
+
+ /// Offset - the base offset of the overrider in the layout class.
+ CharUnits Offset;
+
+ OverriderInfo() : Method(0), Offset(CharUnits::Zero()) { }
+ };
+
+private:
+ /// MostDerivedClass - The most derived class for which the final overriders
+ /// are stored.
+ const CXXRecordDecl *MostDerivedClass;
+
+ /// MostDerivedClassOffset - If we're building final overriders for a
+ /// construction vtable, this holds the offset from the layout class to the
+ /// most derived class.
+ const CharUnits MostDerivedClassOffset;
+
+ /// LayoutClass - The class we're using for layout information. Will be
+ /// different than the most derived class if the final overriders are for a
+ /// construction vtable.
+ const CXXRecordDecl *LayoutClass;
+
+ ASTContext &Context;
+
+ /// MostDerivedClassLayout - the AST record layout of the most derived class.
+ const ASTRecordLayout &MostDerivedClassLayout;
+
+ /// MethodBaseOffsetPairTy - Uniquely identifies a member function
+ /// in a base subobject.
+ typedef std::pair<const CXXMethodDecl *, CharUnits> MethodBaseOffsetPairTy;
+
+ typedef llvm::DenseMap<MethodBaseOffsetPairTy,
+ OverriderInfo> OverridersMapTy;
+
+ /// OverridersMap - The final overriders for all virtual member functions of
+ /// all the base subobjects of the most derived class.
+ OverridersMapTy OverridersMap;
+
+ /// SubobjectsToOffsetsMapTy - A mapping from a base subobject (represented
+ /// as a record decl and a subobject number) and its offsets in the most
+ /// derived class as well as the layout class.
+ typedef llvm::DenseMap<std::pair<const CXXRecordDecl *, unsigned>,
+ CharUnits> SubobjectOffsetMapTy;
+
+ typedef llvm::DenseMap<const CXXRecordDecl *, unsigned> SubobjectCountMapTy;
+
+ /// ComputeBaseOffsets - Compute the offsets for all base subobjects of the
+ /// given base.
+ void ComputeBaseOffsets(BaseSubobject Base, bool IsVirtual,
+ CharUnits OffsetInLayoutClass,
+ SubobjectOffsetMapTy &SubobjectOffsets,
+ SubobjectOffsetMapTy &SubobjectLayoutClassOffsets,
+ SubobjectCountMapTy &SubobjectCounts);
+
+ typedef llvm::SmallPtrSet<const CXXRecordDecl *, 4> VisitedVirtualBasesSetTy;
+
+ /// dump - dump the final overriders for a base subobject, and all its direct
+ /// and indirect base subobjects.
+ void dump(raw_ostream &Out, BaseSubobject Base,
+ VisitedVirtualBasesSetTy& VisitedVirtualBases);
+
+public:
+ FinalOverriders(const CXXRecordDecl *MostDerivedClass,
+ CharUnits MostDerivedClassOffset,
+ const CXXRecordDecl *LayoutClass);
+
+ /// getOverrider - Get the final overrider for the given method declaration in
+ /// the subobject with the given base offset.
+ OverriderInfo getOverrider(const CXXMethodDecl *MD,
+ CharUnits BaseOffset) const {
+ assert(OverridersMap.count(std::make_pair(MD, BaseOffset)) &&
+ "Did not find overrider!");
+
+ return OverridersMap.lookup(std::make_pair(MD, BaseOffset));
+ }
+
+ /// dump - dump the final overriders.
+ void dump() {
+ VisitedVirtualBasesSetTy VisitedVirtualBases;
+ dump(llvm::errs(), BaseSubobject(MostDerivedClass, CharUnits::Zero()),
+ VisitedVirtualBases);
+ }
+
+};
+
+#define DUMP_OVERRIDERS 0
+
+FinalOverriders::FinalOverriders(const CXXRecordDecl *MostDerivedClass,
+ CharUnits MostDerivedClassOffset,
+ const CXXRecordDecl *LayoutClass)
+ : MostDerivedClass(MostDerivedClass),
+ MostDerivedClassOffset(MostDerivedClassOffset), LayoutClass(LayoutClass),
+ Context(MostDerivedClass->getASTContext()),
+ MostDerivedClassLayout(Context.getASTRecordLayout(MostDerivedClass)) {
+
+ // Compute base offsets.
+ SubobjectOffsetMapTy SubobjectOffsets;
+ SubobjectOffsetMapTy SubobjectLayoutClassOffsets;
+ SubobjectCountMapTy SubobjectCounts;
+ ComputeBaseOffsets(BaseSubobject(MostDerivedClass, CharUnits::Zero()),
+ /*IsVirtual=*/false,
+ MostDerivedClassOffset,
+ SubobjectOffsets, SubobjectLayoutClassOffsets,
+ SubobjectCounts);
+
+ // Get the the final overriders.
+ CXXFinalOverriderMap FinalOverriders;
+ MostDerivedClass->getFinalOverriders(FinalOverriders);
+
+ for (CXXFinalOverriderMap::const_iterator I = FinalOverriders.begin(),
+ E = FinalOverriders.end(); I != E; ++I) {
+ const CXXMethodDecl *MD = I->first;
+ const OverridingMethods& Methods = I->second;
+
+ for (OverridingMethods::const_iterator I = Methods.begin(),
+ E = Methods.end(); I != E; ++I) {
+ unsigned SubobjectNumber = I->first;
+ assert(SubobjectOffsets.count(std::make_pair(MD->getParent(),
+ SubobjectNumber)) &&
+ "Did not find subobject offset!");
+
+ CharUnits BaseOffset = SubobjectOffsets[std::make_pair(MD->getParent(),
+ SubobjectNumber)];
+
+ assert(I->second.size() == 1 && "Final overrider is not unique!");
+ const UniqueVirtualMethod &Method = I->second.front();
+
+ const CXXRecordDecl *OverriderRD = Method.Method->getParent();
+ assert(SubobjectLayoutClassOffsets.count(
+ std::make_pair(OverriderRD, Method.Subobject))
+ && "Did not find subobject offset!");
+ CharUnits OverriderOffset =
+ SubobjectLayoutClassOffsets[std::make_pair(OverriderRD,
+ Method.Subobject)];
+
+ OverriderInfo& Overrider = OverridersMap[std::make_pair(MD, BaseOffset)];
+ assert(!Overrider.Method && "Overrider should not exist yet!");
+
+ Overrider.Offset = OverriderOffset;
+ Overrider.Method = Method.Method;
+ }
+ }
+
+#if DUMP_OVERRIDERS
+ // And dump them (for now).
+ dump();
+#endif
+}
+
+static BaseOffset ComputeBaseOffset(ASTContext &Context,
+ const CXXRecordDecl *DerivedRD,
+ const CXXBasePath &Path) {
+ CharUnits NonVirtualOffset = CharUnits::Zero();
+
+ unsigned NonVirtualStart = 0;
+ const CXXRecordDecl *VirtualBase = 0;
+
+ // First, look for the virtual base class.
+ for (unsigned I = 0, E = Path.size(); I != E; ++I) {
+ const CXXBasePathElement &Element = Path[I];
+
+ if (Element.Base->isVirtual()) {
+ // FIXME: Can we break when we find the first virtual base?
+ // (If we can't, can't we just iterate over the path in reverse order?)
+ NonVirtualStart = I + 1;
+ QualType VBaseType = Element.Base->getType();
+ VirtualBase =
+ cast<CXXRecordDecl>(VBaseType->getAs<RecordType>()->getDecl());
+ }
+ }
+
+ // Now compute the non-virtual offset.
+ for (unsigned I = NonVirtualStart, E = Path.size(); I != E; ++I) {
+ const CXXBasePathElement &Element = Path[I];
+
+ // Check the base class offset.
+ const ASTRecordLayout &Layout = Context.getASTRecordLayout(Element.Class);
+
+ const RecordType *BaseType = Element.Base->getType()->getAs<RecordType>();
+ const CXXRecordDecl *Base = cast<CXXRecordDecl>(BaseType->getDecl());
+
+ NonVirtualOffset += Layout.getBaseClassOffset(Base);
+ }
+
+ // FIXME: This should probably use CharUnits or something. Maybe we should
+ // even change the base offsets in ASTRecordLayout to be specified in
+ // CharUnits.
+ return BaseOffset(DerivedRD, VirtualBase, NonVirtualOffset);
+
+}
+
+static BaseOffset ComputeBaseOffset(ASTContext &Context,
+ const CXXRecordDecl *BaseRD,
+ const CXXRecordDecl *DerivedRD) {
+ CXXBasePaths Paths(/*FindAmbiguities=*/false,
+ /*RecordPaths=*/true, /*DetectVirtual=*/false);
+
+ if (!const_cast<CXXRecordDecl *>(DerivedRD)->
+ isDerivedFrom(const_cast<CXXRecordDecl *>(BaseRD), Paths)) {
+ llvm_unreachable("Class must be derived from the passed in base class!");
+ }
+
+ return ComputeBaseOffset(Context, DerivedRD, Paths.front());
+}
+
+static BaseOffset
+ComputeReturnAdjustmentBaseOffset(ASTContext &Context,
+ const CXXMethodDecl *DerivedMD,
+ const CXXMethodDecl *BaseMD) {
+ const FunctionType *BaseFT = BaseMD->getType()->getAs<FunctionType>();
+ const FunctionType *DerivedFT = DerivedMD->getType()->getAs<FunctionType>();
+
+ // Canonicalize the return types.
+ CanQualType CanDerivedReturnType =
+ Context.getCanonicalType(DerivedFT->getResultType());
+ CanQualType CanBaseReturnType =
+ Context.getCanonicalType(BaseFT->getResultType());
+
+ assert(CanDerivedReturnType->getTypeClass() ==
+ CanBaseReturnType->getTypeClass() &&
+ "Types must have same type class!");
+
+ if (CanDerivedReturnType == CanBaseReturnType) {
+ // No adjustment needed.
+ return BaseOffset();
+ }
+
+ if (isa<ReferenceType>(CanDerivedReturnType)) {
+ CanDerivedReturnType =
+ CanDerivedReturnType->getAs<ReferenceType>()->getPointeeType();
+ CanBaseReturnType =
+ CanBaseReturnType->getAs<ReferenceType>()->getPointeeType();
+ } else if (isa<PointerType>(CanDerivedReturnType)) {
+ CanDerivedReturnType =
+ CanDerivedReturnType->getAs<PointerType>()->getPointeeType();
+ CanBaseReturnType =
+ CanBaseReturnType->getAs<PointerType>()->getPointeeType();
+ } else {
+ llvm_unreachable("Unexpected return type!");
+ }
+
+ // We need to compare unqualified types here; consider
+ // const T *Base::foo();
+ // T *Derived::foo();
+ if (CanDerivedReturnType.getUnqualifiedType() ==
+ CanBaseReturnType.getUnqualifiedType()) {
+ // No adjustment needed.
+ return BaseOffset();
+ }
+
+ const CXXRecordDecl *DerivedRD =
+ cast<CXXRecordDecl>(cast<RecordType>(CanDerivedReturnType)->getDecl());
+
+ const CXXRecordDecl *BaseRD =
+ cast<CXXRecordDecl>(cast<RecordType>(CanBaseReturnType)->getDecl());
+
+ return ComputeBaseOffset(Context, BaseRD, DerivedRD);
+}
+
+void
+FinalOverriders::ComputeBaseOffsets(BaseSubobject Base, bool IsVirtual,
+ CharUnits OffsetInLayoutClass,
+ SubobjectOffsetMapTy &SubobjectOffsets,
+ SubobjectOffsetMapTy &SubobjectLayoutClassOffsets,
+ SubobjectCountMapTy &SubobjectCounts) {
+ const CXXRecordDecl *RD = Base.getBase();
+
+ unsigned SubobjectNumber = 0;
+ if (!IsVirtual)
+ SubobjectNumber = ++SubobjectCounts[RD];
+
+ // Set up the subobject to offset mapping.
+ assert(!SubobjectOffsets.count(std::make_pair(RD, SubobjectNumber))
+ && "Subobject offset already exists!");
+ assert(!SubobjectLayoutClassOffsets.count(std::make_pair(RD, SubobjectNumber))
+ && "Subobject offset already exists!");
+
+ SubobjectOffsets[std::make_pair(RD, SubobjectNumber)] = Base.getBaseOffset();
+ SubobjectLayoutClassOffsets[std::make_pair(RD, SubobjectNumber)] =
+ OffsetInLayoutClass;
+
+ // Traverse our bases.
+ for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
+ E = RD->bases_end(); I != E; ++I) {
+ const CXXRecordDecl *BaseDecl =
+ cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
+
+ CharUnits BaseOffset;
+ CharUnits BaseOffsetInLayoutClass;
+ if (I->isVirtual()) {
+ // Check if we've visited this virtual base before.
+ if (SubobjectOffsets.count(std::make_pair(BaseDecl, 0)))
+ continue;
+
+ const ASTRecordLayout &LayoutClassLayout =
+ Context.getASTRecordLayout(LayoutClass);
+
+ BaseOffset = MostDerivedClassLayout.getVBaseClassOffset(BaseDecl);
+ BaseOffsetInLayoutClass =
+ LayoutClassLayout.getVBaseClassOffset(BaseDecl);
+ } else {
+ const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
+ CharUnits Offset = Layout.getBaseClassOffset(BaseDecl);
+
+ BaseOffset = Base.getBaseOffset() + Offset;
+ BaseOffsetInLayoutClass = OffsetInLayoutClass + Offset;
+ }
+
+ ComputeBaseOffsets(BaseSubobject(BaseDecl, BaseOffset),
+ I->isVirtual(), BaseOffsetInLayoutClass,
+ SubobjectOffsets, SubobjectLayoutClassOffsets,
+ SubobjectCounts);
+ }
+}
+
+void FinalOverriders::dump(raw_ostream &Out, BaseSubobject Base,
+ VisitedVirtualBasesSetTy &VisitedVirtualBases) {
+ const CXXRecordDecl *RD = Base.getBase();
+ const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
+
+ for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
+ E = RD->bases_end(); I != E; ++I) {
+ const CXXRecordDecl *BaseDecl =
+ cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
+
+ // Ignore bases that don't have any virtual member functions.
+ if (!BaseDecl->isPolymorphic())
+ continue;
+
+ CharUnits BaseOffset;
+ if (I->isVirtual()) {
+ if (!VisitedVirtualBases.insert(BaseDecl)) {
+ // We've visited this base before.
+ continue;
+ }
+
+ BaseOffset = MostDerivedClassLayout.getVBaseClassOffset(BaseDecl);
+ } else {
+ BaseOffset = Layout.getBaseClassOffset(BaseDecl) + Base.getBaseOffset();
+ }
+
+ dump(Out, BaseSubobject(BaseDecl, BaseOffset), VisitedVirtualBases);
+ }
+
+ Out << "Final overriders for (" << RD->getQualifiedNameAsString() << ", ";
+ Out << Base.getBaseOffset().getQuantity() << ")\n";
+
+ // Now dump the overriders for this base subobject.
+ for (CXXRecordDecl::method_iterator I = RD->method_begin(),
+ E = RD->method_end(); I != E; ++I) {
+ const CXXMethodDecl *MD = *I;
+
+ if (!MD->isVirtual())
+ continue;
+
+ OverriderInfo Overrider = getOverrider(MD, Base.getBaseOffset());
+
+ Out << " " << MD->getQualifiedNameAsString() << " - (";
+ Out << Overrider.Method->getQualifiedNameAsString();
+ Out << ", " << ", " << Overrider.Offset.getQuantity() << ')';
+
+ BaseOffset Offset;
+ if (!Overrider.Method->isPure())
+ Offset = ComputeReturnAdjustmentBaseOffset(Context, Overrider.Method, MD);
+
+ if (!Offset.isEmpty()) {
+ Out << " [ret-adj: ";
+ if (Offset.VirtualBase)
+ Out << Offset.VirtualBase->getQualifiedNameAsString() << " vbase, ";
+
+ Out << Offset.NonVirtualOffset.getQuantity() << " nv]";
+ }
+
+ Out << "\n";
+ }
+}
+
+/// VCallOffsetMap - Keeps track of vcall offsets when building a vtable.
+struct VCallOffsetMap {
+
+ typedef std::pair<const CXXMethodDecl *, CharUnits> MethodAndOffsetPairTy;
+
+ /// Offsets - Keeps track of methods and their offsets.
+ // FIXME: This should be a real map and not a vector.
+ SmallVector<MethodAndOffsetPairTy, 16> Offsets;
+
+ /// MethodsCanShareVCallOffset - Returns whether two virtual member functions
+ /// can share the same vcall offset.
+ static bool MethodsCanShareVCallOffset(const CXXMethodDecl *LHS,
+ const CXXMethodDecl *RHS);
+
+public:
+ /// AddVCallOffset - Adds a vcall offset to the map. Returns true if the
+ /// add was successful, or false if there was already a member function with
+ /// the same signature in the map.
+ bool AddVCallOffset(const CXXMethodDecl *MD, CharUnits OffsetOffset);
+
+ /// getVCallOffsetOffset - Returns the vcall offset offset (relative to the
+ /// vtable address point) for the given virtual member function.
+ CharUnits getVCallOffsetOffset(const CXXMethodDecl *MD);
+
+ // empty - Return whether the offset map is empty or not.
+ bool empty() const { return Offsets.empty(); }
+};
+
+static bool HasSameVirtualSignature(const CXXMethodDecl *LHS,
+ const CXXMethodDecl *RHS) {
+ ASTContext &C = LHS->getASTContext(); // TODO: thread this down
+ CanQual<FunctionProtoType>
+ LT = C.getCanonicalType(LHS->getType()).getAs<FunctionProtoType>(),
+ RT = C.getCanonicalType(RHS->getType()).getAs<FunctionProtoType>();
+
+ // Fast-path matches in the canonical types.
+ if (LT == RT) return true;
+
+ // Force the signatures to match. We can't rely on the overrides
+ // list here because there isn't necessarily an inheritance
+ // relationship between the two methods.
+ if (LT.getQualifiers() != RT.getQualifiers() ||
+ LT->getNumArgs() != RT->getNumArgs())
+ return false;
+ for (unsigned I = 0, E = LT->getNumArgs(); I != E; ++I)
+ if (LT->getArgType(I) != RT->getArgType(I))
+ return false;
+ return true;
+}
+
+bool VCallOffsetMap::MethodsCanShareVCallOffset(const CXXMethodDecl *LHS,
+ const CXXMethodDecl *RHS) {
+ assert(LHS->isVirtual() && "LHS must be virtual!");
+ assert(RHS->isVirtual() && "LHS must be virtual!");
+
+ // A destructor can share a vcall offset with another destructor.
+ if (isa<CXXDestructorDecl>(LHS))
+ return isa<CXXDestructorDecl>(RHS);
+
+ // FIXME: We need to check more things here.
+
+ // The methods must have the same name.
+ DeclarationName LHSName = LHS->getDeclName();
+ DeclarationName RHSName = RHS->getDeclName();
+ if (LHSName != RHSName)
+ return false;
+
+ // And the same signatures.
+ return HasSameVirtualSignature(LHS, RHS);
+}
+
+bool VCallOffsetMap::AddVCallOffset(const CXXMethodDecl *MD,
+ CharUnits OffsetOffset) {
+ // Check if we can reuse an offset.
+ for (unsigned I = 0, E = Offsets.size(); I != E; ++I) {
+ if (MethodsCanShareVCallOffset(Offsets[I].first, MD))
+ return false;
+ }
+
+ // Add the offset.
+ Offsets.push_back(MethodAndOffsetPairTy(MD, OffsetOffset));
+ return true;
+}
+
+CharUnits VCallOffsetMap::getVCallOffsetOffset(const CXXMethodDecl *MD) {
+ // Look for an offset.
+ for (unsigned I = 0, E = Offsets.size(); I != E; ++I) {
+ if (MethodsCanShareVCallOffset(Offsets[I].first, MD))
+ return Offsets[I].second;
+ }
+
+ llvm_unreachable("Should always find a vcall offset offset!");
+}
+
+/// VCallAndVBaseOffsetBuilder - Class for building vcall and vbase offsets.
+class VCallAndVBaseOffsetBuilder {
+public:
+ typedef llvm::DenseMap<const CXXRecordDecl *, CharUnits>
+ VBaseOffsetOffsetsMapTy;
+
+private:
+ /// MostDerivedClass - The most derived class for which we're building vcall
+ /// and vbase offsets.
+ const CXXRecordDecl *MostDerivedClass;
+
+ /// LayoutClass - The class we're using for layout information. Will be
+ /// different than the most derived class if we're building a construction
+ /// vtable.
+ const CXXRecordDecl *LayoutClass;
+
+ /// Context - The ASTContext which we will use for layout information.
+ ASTContext &Context;
+
+ /// Components - vcall and vbase offset components
+ typedef SmallVector<VTableComponent, 64> VTableComponentVectorTy;
+ VTableComponentVectorTy Components;
+
+ /// VisitedVirtualBases - Visited virtual bases.
+ llvm::SmallPtrSet<const CXXRecordDecl *, 4> VisitedVirtualBases;
+
+ /// VCallOffsets - Keeps track of vcall offsets.
+ VCallOffsetMap VCallOffsets;
+
+
+ /// VBaseOffsetOffsets - Contains the offsets of the virtual base offsets,
+ /// relative to the address point.
+ VBaseOffsetOffsetsMapTy VBaseOffsetOffsets;
+
+ /// FinalOverriders - The final overriders of the most derived class.
+ /// (Can be null when we're not building a vtable of the most derived class).
+ const FinalOverriders *Overriders;
+
+ /// AddVCallAndVBaseOffsets - Add vcall offsets and vbase offsets for the
+ /// given base subobject.
+ void AddVCallAndVBaseOffsets(BaseSubobject Base, bool BaseIsVirtual,
+ CharUnits RealBaseOffset);
+
+ /// AddVCallOffsets - Add vcall offsets for the given base subobject.
+ void AddVCallOffsets(BaseSubobject Base, CharUnits VBaseOffset);
+
+ /// AddVBaseOffsets - Add vbase offsets for the given class.
+ void AddVBaseOffsets(const CXXRecordDecl *Base,
+ CharUnits OffsetInLayoutClass);
+
+ /// getCurrentOffsetOffset - Get the current vcall or vbase offset offset in
+ /// chars, relative to the vtable address point.
+ CharUnits getCurrentOffsetOffset() const;
+
+public:
+ VCallAndVBaseOffsetBuilder(const CXXRecordDecl *MostDerivedClass,
+ const CXXRecordDecl *LayoutClass,
+ const FinalOverriders *Overriders,
+ BaseSubobject Base, bool BaseIsVirtual,
+ CharUnits OffsetInLayoutClass)
+ : MostDerivedClass(MostDerivedClass), LayoutClass(LayoutClass),
+ Context(MostDerivedClass->getASTContext()), Overriders(Overriders) {
+
+ // Add vcall and vbase offsets.
+ AddVCallAndVBaseOffsets(Base, BaseIsVirtual, OffsetInLayoutClass);
+ }
+
+ /// Methods for iterating over the components.
+ typedef VTableComponentVectorTy::const_reverse_iterator const_iterator;
+ const_iterator components_begin() const { return Components.rbegin(); }
+ const_iterator components_end() const { return Components.rend(); }
+
+ const VCallOffsetMap &getVCallOffsets() const { return VCallOffsets; }
+ const VBaseOffsetOffsetsMapTy &getVBaseOffsetOffsets() const {
+ return VBaseOffsetOffsets;
+ }
+};
+
+void
+VCallAndVBaseOffsetBuilder::AddVCallAndVBaseOffsets(BaseSubobject Base,
+ bool BaseIsVirtual,
+ CharUnits RealBaseOffset) {
+ const ASTRecordLayout &Layout = Context.getASTRecordLayout(Base.getBase());
+
+ // Itanium C++ ABI 2.5.2:
+ // ..in classes sharing a virtual table with a primary base class, the vcall
+ // and vbase offsets added by the derived class all come before the vcall
+ // and vbase offsets required by the base class, so that the latter may be
+ // laid out as required by the base class without regard to additions from
+ // the derived class(es).
+
+ // (Since we're emitting the vcall and vbase offsets in reverse order, we'll
+ // emit them for the primary base first).
+ if (const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase()) {
+ bool PrimaryBaseIsVirtual = Layout.isPrimaryBaseVirtual();
+
+ CharUnits PrimaryBaseOffset;
+
+ // Get the base offset of the primary base.
+ if (PrimaryBaseIsVirtual) {
+ assert(Layout.getVBaseClassOffsetInBits(PrimaryBase) == 0 &&
+ "Primary vbase should have a zero offset!");
+
+ const ASTRecordLayout &MostDerivedClassLayout =
+ Context.getASTRecordLayout(MostDerivedClass);
+
+ PrimaryBaseOffset =
+ MostDerivedClassLayout.getVBaseClassOffset(PrimaryBase);
+ } else {
+ assert(Layout.getBaseClassOffsetInBits(PrimaryBase) == 0 &&
+ "Primary base should have a zero offset!");
+
+ PrimaryBaseOffset = Base.getBaseOffset();
+ }
+
+ AddVCallAndVBaseOffsets(
+ BaseSubobject(PrimaryBase,PrimaryBaseOffset),
+ PrimaryBaseIsVirtual, RealBaseOffset);
+ }
+
+ AddVBaseOffsets(Base.getBase(), RealBaseOffset);
+
+ // We only want to add vcall offsets for virtual bases.
+ if (BaseIsVirtual)
+ AddVCallOffsets(Base, RealBaseOffset);
+}
+
+CharUnits VCallAndVBaseOffsetBuilder::getCurrentOffsetOffset() const {
+ // OffsetIndex is the index of this vcall or vbase offset, relative to the
+ // vtable address point. (We subtract 3 to account for the information just
+ // above the address point, the RTTI info, the offset to top, and the
+ // vcall offset itself).
+ int64_t OffsetIndex = -(int64_t)(3 + Components.size());
+
+ CharUnits PointerWidth =
+ Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0));
+ CharUnits OffsetOffset = PointerWidth * OffsetIndex;
+ return OffsetOffset;
+}
+
+void VCallAndVBaseOffsetBuilder::AddVCallOffsets(BaseSubobject Base,
+ CharUnits VBaseOffset) {
+ const CXXRecordDecl *RD = Base.getBase();
+ const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
+
+ const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
+
+ // Handle the primary base first.
+ // We only want to add vcall offsets if the base is non-virtual; a virtual
+ // primary base will have its vcall and vbase offsets emitted already.
+ if (PrimaryBase && !Layout.isPrimaryBaseVirtual()) {
+ // Get the base offset of the primary base.
+ assert(Layout.getBaseClassOffsetInBits(PrimaryBase) == 0 &&
+ "Primary base should have a zero offset!");
+
+ AddVCallOffsets(BaseSubobject(PrimaryBase, Base.getBaseOffset()),
+ VBaseOffset);
+ }
+
+ // Add the vcall offsets.
+ for (CXXRecordDecl::method_iterator I = RD->method_begin(),
+ E = RD->method_end(); I != E; ++I) {
+ const CXXMethodDecl *MD = *I;
+
+ if (!MD->isVirtual())
+ continue;
+
+ CharUnits OffsetOffset = getCurrentOffsetOffset();
+
+ // Don't add a vcall offset if we already have one for this member function
+ // signature.
+ if (!VCallOffsets.AddVCallOffset(MD, OffsetOffset))
+ continue;
+
+ CharUnits Offset = CharUnits::Zero();
+
+ if (Overriders) {
+ // Get the final overrider.
+ FinalOverriders::OverriderInfo Overrider =
+ Overriders->getOverrider(MD, Base.getBaseOffset());
+
+ /// The vcall offset is the offset from the virtual base to the object
+ /// where the function was overridden.
+ Offset = Overrider.Offset - VBaseOffset;
+ }
+
+ Components.push_back(
+ VTableComponent::MakeVCallOffset(Offset));
+ }
+
+ // And iterate over all non-virtual bases (ignoring the primary base).
+ for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
+ E = RD->bases_end(); I != E; ++I) {
+
+ if (I->isVirtual())
+ continue;
+
+ const CXXRecordDecl *BaseDecl =
+ cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
+ if (BaseDecl == PrimaryBase)
+ continue;
+
+ // Get the base offset of this base.
+ CharUnits BaseOffset = Base.getBaseOffset() +
+ Layout.getBaseClassOffset(BaseDecl);
+
+ AddVCallOffsets(BaseSubobject(BaseDecl, BaseOffset),
+ VBaseOffset);
+ }
+}
+
+void
+VCallAndVBaseOffsetBuilder::AddVBaseOffsets(const CXXRecordDecl *RD,
+ CharUnits OffsetInLayoutClass) {
+ const ASTRecordLayout &LayoutClassLayout =
+ Context.getASTRecordLayout(LayoutClass);
+
+ // Add vbase offsets.
+ for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
+ E = RD->bases_end(); I != E; ++I) {
+ const CXXRecordDecl *BaseDecl =
+ cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
+
+ // Check if this is a virtual base that we haven't visited before.
+ if (I->isVirtual() && VisitedVirtualBases.insert(BaseDecl)) {
+ CharUnits Offset =
+ LayoutClassLayout.getVBaseClassOffset(BaseDecl) - OffsetInLayoutClass;
+
+ // Add the vbase offset offset.
+ assert(!VBaseOffsetOffsets.count(BaseDecl) &&
+ "vbase offset offset already exists!");
+
+ CharUnits VBaseOffsetOffset = getCurrentOffsetOffset();
+ VBaseOffsetOffsets.insert(
+ std::make_pair(BaseDecl, VBaseOffsetOffset));
+
+ Components.push_back(
+ VTableComponent::MakeVBaseOffset(Offset));
+ }
+
+ // Check the base class looking for more vbase offsets.
+ AddVBaseOffsets(BaseDecl, OffsetInLayoutClass);
+ }
+}
+
+/// VTableBuilder - Class for building vtable layout information.
+class VTableBuilder {
+public:
+ /// PrimaryBasesSetVectorTy - A set vector of direct and indirect
+ /// primary bases.
+ typedef llvm::SmallSetVector<const CXXRecordDecl *, 8>
+ PrimaryBasesSetVectorTy;
+
+ typedef llvm::DenseMap<const CXXRecordDecl *, CharUnits>
+ VBaseOffsetOffsetsMapTy;
+
+ typedef llvm::DenseMap<BaseSubobject, uint64_t>
+ AddressPointsMapTy;
+
+private:
+ /// VTables - Global vtable information.
+ VTableContext &VTables;
+
+ /// MostDerivedClass - The most derived class for which we're building this
+ /// vtable.
+ const CXXRecordDecl *MostDerivedClass;
+
+ /// MostDerivedClassOffset - If we're building a construction vtable, this
+ /// holds the offset from the layout class to the most derived class.
+ const CharUnits MostDerivedClassOffset;
+
+ /// MostDerivedClassIsVirtual - Whether the most derived class is a virtual
+ /// base. (This only makes sense when building a construction vtable).
+ bool MostDerivedClassIsVirtual;
+
+ /// LayoutClass - The class we're using for layout information. Will be
+ /// different than the most derived class if we're building a construction
+ /// vtable.
+ const CXXRecordDecl *LayoutClass;
+
+ /// Context - The ASTContext which we will use for layout information.
+ ASTContext &Context;
+
+ /// FinalOverriders - The final overriders of the most derived class.
+ const FinalOverriders Overriders;
+
+ /// VCallOffsetsForVBases - Keeps track of vcall offsets for the virtual
+ /// bases in this vtable.
+ llvm::DenseMap<const CXXRecordDecl *, VCallOffsetMap> VCallOffsetsForVBases;
+
+ /// VBaseOffsetOffsets - Contains the offsets of the virtual base offsets for
+ /// the most derived class.
+ VBaseOffsetOffsetsMapTy VBaseOffsetOffsets;
+
+ /// Components - The components of the vtable being built.
+ SmallVector<VTableComponent, 64> Components;
+
+ /// AddressPoints - Address points for the vtable being built.
+ AddressPointsMapTy AddressPoints;
+
+ /// MethodInfo - Contains information about a method in a vtable.
+ /// (Used for computing 'this' pointer adjustment thunks.
+ struct MethodInfo {
+ /// BaseOffset - The base offset of this method.
+ const CharUnits BaseOffset;
+
+ /// BaseOffsetInLayoutClass - The base offset in the layout class of this
+ /// method.
+ const CharUnits BaseOffsetInLayoutClass;
+
+ /// VTableIndex - The index in the vtable that this method has.
+ /// (For destructors, this is the index of the complete destructor).
+ const uint64_t VTableIndex;
+
+ MethodInfo(CharUnits BaseOffset, CharUnits BaseOffsetInLayoutClass,
+ uint64_t VTableIndex)
+ : BaseOffset(BaseOffset),
+ BaseOffsetInLayoutClass(BaseOffsetInLayoutClass),
+ VTableIndex(VTableIndex) { }
+
+ MethodInfo()
+ : BaseOffset(CharUnits::Zero()),
+ BaseOffsetInLayoutClass(CharUnits::Zero()),
+ VTableIndex(0) { }
+ };
+
+ typedef llvm::DenseMap<const CXXMethodDecl *, MethodInfo> MethodInfoMapTy;
+
+ /// MethodInfoMap - The information for all methods in the vtable we're
+ /// currently building.
+ MethodInfoMapTy MethodInfoMap;
+
+ typedef llvm::DenseMap<uint64_t, ThunkInfo> VTableThunksMapTy;
+
+ /// VTableThunks - The thunks by vtable index in the vtable currently being
+ /// built.
+ VTableThunksMapTy VTableThunks;
+
+ typedef SmallVector<ThunkInfo, 1> ThunkInfoVectorTy;
+ typedef llvm::DenseMap<const CXXMethodDecl *, ThunkInfoVectorTy> ThunksMapTy;
+
+ /// Thunks - A map that contains all the thunks needed for all methods in the
+ /// most derived class for which the vtable is currently being built.
+ ThunksMapTy Thunks;
+
+ /// AddThunk - Add a thunk for the given method.
+ void AddThunk(const CXXMethodDecl *MD, const ThunkInfo &Thunk);
+
+ /// ComputeThisAdjustments - Compute the 'this' pointer adjustments for the
+ /// part of the vtable we're currently building.
+ void ComputeThisAdjustments();
+
+ typedef llvm::SmallPtrSet<const CXXRecordDecl *, 4> VisitedVirtualBasesSetTy;
+
+ /// PrimaryVirtualBases - All known virtual bases who are a primary base of
+ /// some other base.
+ VisitedVirtualBasesSetTy PrimaryVirtualBases;
+
+ /// ComputeReturnAdjustment - Compute the return adjustment given a return
+ /// adjustment base offset.
+ ReturnAdjustment ComputeReturnAdjustment(BaseOffset Offset);
+
+ /// ComputeThisAdjustmentBaseOffset - Compute the base offset for adjusting
+ /// the 'this' pointer from the base subobject to the derived subobject.
+ BaseOffset ComputeThisAdjustmentBaseOffset(BaseSubobject Base,
+ BaseSubobject Derived) const;
+
+ /// ComputeThisAdjustment - Compute the 'this' pointer adjustment for the
+ /// given virtual member function, its offset in the layout class and its
+ /// final overrider.
+ ThisAdjustment
+ ComputeThisAdjustment(const CXXMethodDecl *MD,
+ CharUnits BaseOffsetInLayoutClass,
+ FinalOverriders::OverriderInfo Overrider);
+
+ /// AddMethod - Add a single virtual member function to the vtable
+ /// components vector.
+ void AddMethod(const CXXMethodDecl *MD, ReturnAdjustment ReturnAdjustment);
+
+ /// IsOverriderUsed - Returns whether the overrider will ever be used in this
+ /// part of the vtable.
+ ///
+ /// Itanium C++ ABI 2.5.2:
+ ///
+ /// struct A { virtual void f(); };
+ /// struct B : virtual public A { int i; };
+ /// struct C : virtual public A { int j; };
+ /// struct D : public B, public C {};
+ ///
+ /// When B and C are declared, A is a primary base in each case, so although
+ /// vcall offsets are allocated in the A-in-B and A-in-C vtables, no this
+ /// adjustment is required and no thunk is generated. However, inside D
+ /// objects, A is no longer a primary base of C, so if we allowed calls to
+ /// C::f() to use the copy of A's vtable in the C subobject, we would need
+ /// to adjust this from C* to B::A*, which would require a third-party
+ /// thunk. Since we require that a call to C::f() first convert to A*,
+ /// C-in-D's copy of A's vtable is never referenced, so this is not
+ /// necessary.
+ bool IsOverriderUsed(const CXXMethodDecl *Overrider,
+ CharUnits BaseOffsetInLayoutClass,
+ const CXXRecordDecl *FirstBaseInPrimaryBaseChain,
+ CharUnits FirstBaseOffsetInLayoutClass) const;
+
+
+ /// AddMethods - Add the methods of this base subobject and all its
+ /// primary bases to the vtable components vector.
+ void AddMethods(BaseSubobject Base, CharUnits BaseOffsetInLayoutClass,
+ const CXXRecordDecl *FirstBaseInPrimaryBaseChain,
+ CharUnits FirstBaseOffsetInLayoutClass,
+ PrimaryBasesSetVectorTy &PrimaryBases);
+
+ // LayoutVTable - Layout the vtable for the given base class, including its
+ // secondary vtables and any vtables for virtual bases.
+ void LayoutVTable();
+
+ /// LayoutPrimaryAndSecondaryVTables - Layout the primary vtable for the
+ /// given base subobject, as well as all its secondary vtables.
+ ///
+ /// \param BaseIsMorallyVirtual whether the base subobject is a virtual base
+ /// or a direct or indirect base of a virtual base.
+ ///
+ /// \param BaseIsVirtualInLayoutClass - Whether the base subobject is virtual
+ /// in the layout class.
+ void LayoutPrimaryAndSecondaryVTables(BaseSubobject Base,
+ bool BaseIsMorallyVirtual,
+ bool BaseIsVirtualInLayoutClass,
+ CharUnits OffsetInLayoutClass);
+
+ /// LayoutSecondaryVTables - Layout the secondary vtables for the given base
+ /// subobject.
+ ///
+ /// \param BaseIsMorallyVirtual whether the base subobject is a virtual base
+ /// or a direct or indirect base of a virtual base.
+ void LayoutSecondaryVTables(BaseSubobject Base, bool BaseIsMorallyVirtual,
+ CharUnits OffsetInLayoutClass);
+
+ /// DeterminePrimaryVirtualBases - Determine the primary virtual bases in this
+ /// class hierarchy.
+ void DeterminePrimaryVirtualBases(const CXXRecordDecl *RD,
+ CharUnits OffsetInLayoutClass,
+ VisitedVirtualBasesSetTy &VBases);
+
+ /// LayoutVTablesForVirtualBases - Layout vtables for all virtual bases of the
+ /// given base (excluding any primary bases).
+ void LayoutVTablesForVirtualBases(const CXXRecordDecl *RD,
+ VisitedVirtualBasesSetTy &VBases);
+
+ /// isBuildingConstructionVTable - Return whether this vtable builder is
+ /// building a construction vtable.
+ bool isBuildingConstructorVTable() const {
+ return MostDerivedClass != LayoutClass;
+ }
+
+public:
+ VTableBuilder(VTableContext &VTables, const CXXRecordDecl *MostDerivedClass,
+ CharUnits MostDerivedClassOffset,
+ bool MostDerivedClassIsVirtual, const
+ CXXRecordDecl *LayoutClass)
+ : VTables(VTables), MostDerivedClass(MostDerivedClass),
+ MostDerivedClassOffset(MostDerivedClassOffset),
+ MostDerivedClassIsVirtual(MostDerivedClassIsVirtual),
+ LayoutClass(LayoutClass), Context(MostDerivedClass->getASTContext()),
+ Overriders(MostDerivedClass, MostDerivedClassOffset, LayoutClass) {
+
+ LayoutVTable();
+
+ if (Context.getLangOptions().DumpVTableLayouts)
+ dumpLayout(llvm::errs());
+ }
+
+ uint64_t getNumThunks() const {
+ return Thunks.size();
+ }
+
+ ThunksMapTy::const_iterator thunks_begin() const {
+ return Thunks.begin();
+ }
+
+ ThunksMapTy::const_iterator thunks_end() const {
+ return Thunks.end();
+ }
+
+ const VBaseOffsetOffsetsMapTy &getVBaseOffsetOffsets() const {
+ return VBaseOffsetOffsets;
+ }
+
+ const AddressPointsMapTy &getAddressPoints() const {
+ return AddressPoints;
+ }
+
+ /// getNumVTableComponents - Return the number of components in the vtable
+ /// currently built.
+ uint64_t getNumVTableComponents() const {
+ return Components.size();
+ }
+
+ const VTableComponent *vtable_component_begin() const {
+ return Components.begin();
+ }
+
+ const VTableComponent *vtable_component_end() const {
+ return Components.end();
+ }
+
+ AddressPointsMapTy::const_iterator address_points_begin() const {
+ return AddressPoints.begin();
+ }
+
+ AddressPointsMapTy::const_iterator address_points_end() const {
+ return AddressPoints.end();
+ }
+
+ VTableThunksMapTy::const_iterator vtable_thunks_begin() const {
+ return VTableThunks.begin();
+ }
+
+ VTableThunksMapTy::const_iterator vtable_thunks_end() const {
+ return VTableThunks.end();
+ }
+
+ /// dumpLayout - Dump the vtable layout.
+ void dumpLayout(raw_ostream&);
+};
+
+void VTableBuilder::AddThunk(const CXXMethodDecl *MD, const ThunkInfo &Thunk) {
+ assert(!isBuildingConstructorVTable() &&
+ "Can't add thunks for construction vtable");
+
+ SmallVector<ThunkInfo, 1> &ThunksVector = Thunks[MD];
+
+ // Check if we have this thunk already.
+ if (std::find(ThunksVector.begin(), ThunksVector.end(), Thunk) !=
+ ThunksVector.end())
+ return;
+
+ ThunksVector.push_back(Thunk);
+}
+
+typedef llvm::SmallPtrSet<const CXXMethodDecl *, 8> OverriddenMethodsSetTy;
+
+/// ComputeAllOverriddenMethods - Given a method decl, will return a set of all
+/// the overridden methods that the function decl overrides.
+static void
+ComputeAllOverriddenMethods(const CXXMethodDecl *MD,
+ OverriddenMethodsSetTy& OverriddenMethods) {
+ assert(MD->isVirtual() && "Method is not virtual!");
+
+ for (CXXMethodDecl::method_iterator I = MD->begin_overridden_methods(),
+ E = MD->end_overridden_methods(); I != E; ++I) {
+ const CXXMethodDecl *OverriddenMD = *I;
+
+ OverriddenMethods.insert(OverriddenMD);
+
+ ComputeAllOverriddenMethods(OverriddenMD, OverriddenMethods);
+ }
+}
+
+void VTableBuilder::ComputeThisAdjustments() {
+ // Now go through the method info map and see if any of the methods need
+ // 'this' pointer adjustments.
+ for (MethodInfoMapTy::const_iterator I = MethodInfoMap.begin(),
+ E = MethodInfoMap.end(); I != E; ++I) {
+ const CXXMethodDecl *MD = I->first;
+ const MethodInfo &MethodInfo = I->second;
+
+ // Ignore adjustments for unused function pointers.
+ uint64_t VTableIndex = MethodInfo.VTableIndex;
+ if (Components[VTableIndex].getKind() ==
+ VTableComponent::CK_UnusedFunctionPointer)
+ continue;
+
+ // Get the final overrider for this method.
+ FinalOverriders::OverriderInfo Overrider =
+ Overriders.getOverrider(MD, MethodInfo.BaseOffset);
+
+ // Check if we need an adjustment at all.
+ if (MethodInfo.BaseOffsetInLayoutClass == Overrider.Offset) {
+ // When a return thunk is needed by a derived class that overrides a
+ // virtual base, gcc uses a virtual 'this' adjustment as well.
+ // While the thunk itself might be needed by vtables in subclasses or
+ // in construction vtables, there doesn't seem to be a reason for using
+ // the thunk in this vtable. Still, we do so to match gcc.
+ if (VTableThunks.lookup(VTableIndex).Return.isEmpty())
+ continue;
+ }
+
+ ThisAdjustment ThisAdjustment =
+ ComputeThisAdjustment(MD, MethodInfo.BaseOffsetInLayoutClass, Overrider);
+
+ if (ThisAdjustment.isEmpty())
+ continue;
+
+ // Add it.
+ VTableThunks[VTableIndex].This = ThisAdjustment;
+
+ if (isa<CXXDestructorDecl>(MD)) {
+ // Add an adjustment for the deleting destructor as well.
+ VTableThunks[VTableIndex + 1].This = ThisAdjustment;
+ }
+ }
+
+ /// Clear the method info map.
+ MethodInfoMap.clear();
+
+ if (isBuildingConstructorVTable()) {
+ // We don't need to store thunk information for construction vtables.
+ return;
+ }
+
+ for (VTableThunksMapTy::const_iterator I = VTableThunks.begin(),
+ E = VTableThunks.end(); I != E; ++I) {
+ const VTableComponent &Component = Components[I->first];
+ const ThunkInfo &Thunk = I->second;
+ const CXXMethodDecl *MD;
+
+ switch (Component.getKind()) {
+ default:
+ llvm_unreachable("Unexpected vtable component kind!");
+ case VTableComponent::CK_FunctionPointer:
+ MD = Component.getFunctionDecl();
+ break;
+ case VTableComponent::CK_CompleteDtorPointer:
+ MD = Component.getDestructorDecl();
+ break;
+ case VTableComponent::CK_DeletingDtorPointer:
+ // We've already added the thunk when we saw the complete dtor pointer.
+ continue;
+ }
+
+ if (MD->getParent() == MostDerivedClass)
+ AddThunk(MD, Thunk);
+ }
+}
+
+ReturnAdjustment VTableBuilder::ComputeReturnAdjustment(BaseOffset Offset) {
+ ReturnAdjustment Adjustment;
+
+ if (!Offset.isEmpty()) {
+ if (Offset.VirtualBase) {
+ // Get the virtual base offset offset.
+ if (Offset.DerivedClass == MostDerivedClass) {
+ // We can get the offset offset directly from our map.
+ Adjustment.VBaseOffsetOffset =
+ VBaseOffsetOffsets.lookup(Offset.VirtualBase).getQuantity();
+ } else {
+ Adjustment.VBaseOffsetOffset =
+ VTables.getVirtualBaseOffsetOffset(Offset.DerivedClass,
+ Offset.VirtualBase).getQuantity();
+ }
+ }
+
+ Adjustment.NonVirtual = Offset.NonVirtualOffset.getQuantity();
+ }
+
+ return Adjustment;
+}
+
+BaseOffset
+VTableBuilder::ComputeThisAdjustmentBaseOffset(BaseSubobject Base,
+ BaseSubobject Derived) const {
+ const CXXRecordDecl *BaseRD = Base.getBase();
+ const CXXRecordDecl *DerivedRD = Derived.getBase();
+
+ CXXBasePaths Paths(/*FindAmbiguities=*/true,
+ /*RecordPaths=*/true, /*DetectVirtual=*/true);
+
+ if (!const_cast<CXXRecordDecl *>(DerivedRD)->
+ isDerivedFrom(const_cast<CXXRecordDecl *>(BaseRD), Paths)) {
+ llvm_unreachable("Class must be derived from the passed in base class!");
+ }
+
+ // We have to go through all the paths, and see which one leads us to the
+ // right base subobject.
+ for (CXXBasePaths::const_paths_iterator I = Paths.begin(), E = Paths.end();
+ I != E; ++I) {
+ BaseOffset Offset = ComputeBaseOffset(Context, DerivedRD, *I);
+
+ CharUnits OffsetToBaseSubobject = Offset.NonVirtualOffset;
+
+ if (Offset.VirtualBase) {
+ // If we have a virtual base class, the non-virtual offset is relative
+ // to the virtual base class offset.
+ const ASTRecordLayout &LayoutClassLayout =
+ Context.getASTRecordLayout(LayoutClass);
+
+ /// Get the virtual base offset, relative to the most derived class
+ /// layout.
+ OffsetToBaseSubobject +=
+ LayoutClassLayout.getVBaseClassOffset(Offset.VirtualBase);
+ } else {
+ // Otherwise, the non-virtual offset is relative to the derived class
+ // offset.
+ OffsetToBaseSubobject += Derived.getBaseOffset();
+ }
+
+ // Check if this path gives us the right base subobject.
+ if (OffsetToBaseSubobject == Base.getBaseOffset()) {
+ // Since we're going from the base class _to_ the derived class, we'll
+ // invert the non-virtual offset here.
+ Offset.NonVirtualOffset = -Offset.NonVirtualOffset;
+ return Offset;
+ }
+ }
+
+ return BaseOffset();
+}
+
+ThisAdjustment
+VTableBuilder::ComputeThisAdjustment(const CXXMethodDecl *MD,
+ CharUnits BaseOffsetInLayoutClass,
+ FinalOverriders::OverriderInfo Overrider) {
+ // Ignore adjustments for pure virtual member functions.
+ if (Overrider.Method->isPure())
+ return ThisAdjustment();
+
+ BaseSubobject OverriddenBaseSubobject(MD->getParent(),
+ BaseOffsetInLayoutClass);
+
+ BaseSubobject OverriderBaseSubobject(Overrider.Method->getParent(),
+ Overrider.Offset);
+
+ // Compute the adjustment offset.
+ BaseOffset Offset = ComputeThisAdjustmentBaseOffset(OverriddenBaseSubobject,
+ OverriderBaseSubobject);
+ if (Offset.isEmpty())
+ return ThisAdjustment();
+
+ ThisAdjustment Adjustment;
+
+ if (Offset.VirtualBase) {
+ // Get the vcall offset map for this virtual base.
+ VCallOffsetMap &VCallOffsets = VCallOffsetsForVBases[Offset.VirtualBase];
+
+ if (VCallOffsets.empty()) {
+ // We don't have vcall offsets for this virtual base, go ahead and
+ // build them.
+ VCallAndVBaseOffsetBuilder Builder(MostDerivedClass, MostDerivedClass,
+ /*FinalOverriders=*/0,
+ BaseSubobject(Offset.VirtualBase,
+ CharUnits::Zero()),
+ /*BaseIsVirtual=*/true,
+ /*OffsetInLayoutClass=*/
+ CharUnits::Zero());
+
+ VCallOffsets = Builder.getVCallOffsets();
+ }
+
+ Adjustment.VCallOffsetOffset =
+ VCallOffsets.getVCallOffsetOffset(MD).getQuantity();
+ }
+
+ // Set the non-virtual part of the adjustment.
+ Adjustment.NonVirtual = Offset.NonVirtualOffset.getQuantity();
+
+ return Adjustment;
+}
+
+void
+VTableBuilder::AddMethod(const CXXMethodDecl *MD,
+ ReturnAdjustment ReturnAdjustment) {
+ if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
+ assert(ReturnAdjustment.isEmpty() &&
+ "Destructor can't have return adjustment!");
+
+ // Add both the complete destructor and the deleting destructor.
+ Components.push_back(VTableComponent::MakeCompleteDtor(DD));
+ Components.push_back(VTableComponent::MakeDeletingDtor(DD));
+ } else {
+ // Add the return adjustment if necessary.
+ if (!ReturnAdjustment.isEmpty())
+ VTableThunks[Components.size()].Return = ReturnAdjustment;
+
+ // Add the function.
+ Components.push_back(VTableComponent::MakeFunction(MD));
+ }
+}
+
+/// OverridesIndirectMethodInBase - Return whether the given member function
+/// overrides any methods in the set of given bases.
+/// Unlike OverridesMethodInBase, this checks "overriders of overriders".
+/// For example, if we have:
+///
+/// struct A { virtual void f(); }
+/// struct B : A { virtual void f(); }
+/// struct C : B { virtual void f(); }
+///
+/// OverridesIndirectMethodInBase will return true if given C::f as the method
+/// and { A } as the set of bases.
+static bool
+OverridesIndirectMethodInBases(const CXXMethodDecl *MD,
+ VTableBuilder::PrimaryBasesSetVectorTy &Bases) {
+ if (Bases.count(MD->getParent()))
+ return true;
+
+ for (CXXMethodDecl::method_iterator I = MD->begin_overridden_methods(),
+ E = MD->end_overridden_methods(); I != E; ++I) {
+ const CXXMethodDecl *OverriddenMD = *I;
+
+ // Check "indirect overriders".
+ if (OverridesIndirectMethodInBases(OverriddenMD, Bases))
+ return true;
+ }
+
+ return false;
+}
+
+bool
+VTableBuilder::IsOverriderUsed(const CXXMethodDecl *Overrider,
+ CharUnits BaseOffsetInLayoutClass,
+ const CXXRecordDecl *FirstBaseInPrimaryBaseChain,
+ CharUnits FirstBaseOffsetInLayoutClass) const {
+ // If the base and the first base in the primary base chain have the same
+ // offsets, then this overrider will be used.
+ if (BaseOffsetInLayoutClass == FirstBaseOffsetInLayoutClass)
+ return true;
+
+ // We know now that Base (or a direct or indirect base of it) is a primary
+ // base in part of the class hierarchy, but not a primary base in the most
+ // derived class.
+
+ // If the overrider is the first base in the primary base chain, we know
+ // that the overrider will be used.
+ if (Overrider->getParent() == FirstBaseInPrimaryBaseChain)
+ return true;
+
+ VTableBuilder::PrimaryBasesSetVectorTy PrimaryBases;
+
+ const CXXRecordDecl *RD = FirstBaseInPrimaryBaseChain;
+ PrimaryBases.insert(RD);
+
+ // Now traverse the base chain, starting with the first base, until we find
+ // the base that is no longer a primary base.
+ while (true) {
+ const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
+ const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
+
+ if (!PrimaryBase)
+ break;
+
+ if (Layout.isPrimaryBaseVirtual()) {
+ assert(Layout.getVBaseClassOffsetInBits(PrimaryBase) == 0 &&
+ "Primary base should always be at offset 0!");
+
+ const ASTRecordLayout &LayoutClassLayout =
+ Context.getASTRecordLayout(LayoutClass);
+
+ // Now check if this is the primary base that is not a primary base in the
+ // most derived class.
+ if (LayoutClassLayout.getVBaseClassOffset(PrimaryBase) !=
+ FirstBaseOffsetInLayoutClass) {
+ // We found it, stop walking the chain.
+ break;
+ }
+ } else {
+ assert(Layout.getBaseClassOffsetInBits(PrimaryBase) == 0 &&
+ "Primary base should always be at offset 0!");
+ }
+
+ if (!PrimaryBases.insert(PrimaryBase))
+ llvm_unreachable("Found a duplicate primary base!");
+
+ RD = PrimaryBase;
+ }
+
+ // If the final overrider is an override of one of the primary bases,
+ // then we know that it will be used.
+ return OverridesIndirectMethodInBases(Overrider, PrimaryBases);
+}
+
+/// FindNearestOverriddenMethod - Given a method, returns the overridden method
+/// from the nearest base. Returns null if no method was found.
+static const CXXMethodDecl *
+FindNearestOverriddenMethod(const CXXMethodDecl *MD,
+ VTableBuilder::PrimaryBasesSetVectorTy &Bases) {
+ OverriddenMethodsSetTy OverriddenMethods;
+ ComputeAllOverriddenMethods(MD, OverriddenMethods);
+
+ for (int I = Bases.size(), E = 0; I != E; --I) {
+ const CXXRecordDecl *PrimaryBase = Bases[I - 1];
+
+ // Now check the overriden methods.
+ for (OverriddenMethodsSetTy::const_iterator I = OverriddenMethods.begin(),
+ E = OverriddenMethods.end(); I != E; ++I) {
+ const CXXMethodDecl *OverriddenMD = *I;
+
+ // We found our overridden method.
+ if (OverriddenMD->getParent() == PrimaryBase)
+ return OverriddenMD;
+ }
+ }
+
+ return 0;
+}
+
+void
+VTableBuilder::AddMethods(BaseSubobject Base, CharUnits BaseOffsetInLayoutClass,
+ const CXXRecordDecl *FirstBaseInPrimaryBaseChain,
+ CharUnits FirstBaseOffsetInLayoutClass,
+ PrimaryBasesSetVectorTy &PrimaryBases) {
+ const CXXRecordDecl *RD = Base.getBase();
+ const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
+
+ if (const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase()) {
+ CharUnits PrimaryBaseOffset;
+ CharUnits PrimaryBaseOffsetInLayoutClass;
+ if (Layout.isPrimaryBaseVirtual()) {
+ assert(Layout.getVBaseClassOffsetInBits(PrimaryBase) == 0 &&
+ "Primary vbase should have a zero offset!");
+
+ const ASTRecordLayout &MostDerivedClassLayout =
+ Context.getASTRecordLayout(MostDerivedClass);
+
+ PrimaryBaseOffset =
+ MostDerivedClassLayout.getVBaseClassOffset(PrimaryBase);
+
+ const ASTRecordLayout &LayoutClassLayout =
+ Context.getASTRecordLayout(LayoutClass);
+
+ PrimaryBaseOffsetInLayoutClass =
+ LayoutClassLayout.getVBaseClassOffset(PrimaryBase);
+ } else {
+ assert(Layout.getBaseClassOffsetInBits(PrimaryBase) == 0 &&
+ "Primary base should have a zero offset!");
+
+ PrimaryBaseOffset = Base.getBaseOffset();
+ PrimaryBaseOffsetInLayoutClass = BaseOffsetInLayoutClass;
+ }
+
+ AddMethods(BaseSubobject(PrimaryBase, PrimaryBaseOffset),
+ PrimaryBaseOffsetInLayoutClass, FirstBaseInPrimaryBaseChain,
+ FirstBaseOffsetInLayoutClass, PrimaryBases);
+
+ if (!PrimaryBases.insert(PrimaryBase))
+ llvm_unreachable("Found a duplicate primary base!");
+ }
+
+ // Now go through all virtual member functions and add them.
+ for (CXXRecordDecl::method_iterator I = RD->method_begin(),
+ E = RD->method_end(); I != E; ++I) {
+ const CXXMethodDecl *MD = *I;
+
+ if (!MD->isVirtual())
+ continue;
+
+ // Get the final overrider.
+ FinalOverriders::OverriderInfo Overrider =
+ Overriders.getOverrider(MD, Base.getBaseOffset());
+
+ // Check if this virtual member function overrides a method in a primary
+ // base. If this is the case, and the return type doesn't require adjustment
+ // then we can just use the member function from the primary base.
+ if (const CXXMethodDecl *OverriddenMD =
+ FindNearestOverriddenMethod(MD, PrimaryBases)) {
+ if (ComputeReturnAdjustmentBaseOffset(Context, MD,
+ OverriddenMD).isEmpty()) {
+ // Replace the method info of the overridden method with our own
+ // method.
+ assert(MethodInfoMap.count(OverriddenMD) &&
+ "Did not find the overridden method!");
+ MethodInfo &OverriddenMethodInfo = MethodInfoMap[OverriddenMD];
+
+ MethodInfo MethodInfo(Base.getBaseOffset(), BaseOffsetInLayoutClass,
+ OverriddenMethodInfo.VTableIndex);
+
+ assert(!MethodInfoMap.count(MD) &&
+ "Should not have method info for this method yet!");
+
+ MethodInfoMap.insert(std::make_pair(MD, MethodInfo));
+ MethodInfoMap.erase(OverriddenMD);
+
+ // If the overridden method exists in a virtual base class or a direct
+ // or indirect base class of a virtual base class, we need to emit a
+ // thunk if we ever have a class hierarchy where the base class is not
+ // a primary base in the complete object.
+ if (!isBuildingConstructorVTable() && OverriddenMD != MD) {
+ // Compute the this adjustment.
+ ThisAdjustment ThisAdjustment =
+ ComputeThisAdjustment(OverriddenMD, BaseOffsetInLayoutClass,
+ Overrider);
+
+ if (ThisAdjustment.VCallOffsetOffset &&
+ Overrider.Method->getParent() == MostDerivedClass) {
+
+ // There's no return adjustment from OverriddenMD and MD,
+ // but that doesn't mean there isn't one between MD and
+ // the final overrider.
+ BaseOffset ReturnAdjustmentOffset =
+ ComputeReturnAdjustmentBaseOffset(Context, Overrider.Method, MD);
+ ReturnAdjustment ReturnAdjustment =
+ ComputeReturnAdjustment(ReturnAdjustmentOffset);
+
+ // This is a virtual thunk for the most derived class, add it.
+ AddThunk(Overrider.Method,
+ ThunkInfo(ThisAdjustment, ReturnAdjustment));
+ }
+ }
+
+ continue;
+ }
+ }
+
+ // Insert the method info for this method.
+ MethodInfo MethodInfo(Base.getBaseOffset(), BaseOffsetInLayoutClass,
+ Components.size());
+
+ assert(!MethodInfoMap.count(MD) &&
+ "Should not have method info for this method yet!");
+ MethodInfoMap.insert(std::make_pair(MD, MethodInfo));
+
+ // Check if this overrider is going to be used.
+ const CXXMethodDecl *OverriderMD = Overrider.Method;
+ if (!IsOverriderUsed(OverriderMD, BaseOffsetInLayoutClass,
+ FirstBaseInPrimaryBaseChain,
+ FirstBaseOffsetInLayoutClass)) {
+ Components.push_back(VTableComponent::MakeUnusedFunction(OverriderMD));
+ continue;
+ }
+
+ // Check if this overrider needs a return adjustment.
+ // We don't want to do this for pure virtual member functions.
+ BaseOffset ReturnAdjustmentOffset;
+ if (!OverriderMD->isPure()) {
+ ReturnAdjustmentOffset =
+ ComputeReturnAdjustmentBaseOffset(Context, OverriderMD, MD);
+ }
+
+ ReturnAdjustment ReturnAdjustment =
+ ComputeReturnAdjustment(ReturnAdjustmentOffset);
+
+ AddMethod(Overrider.Method, ReturnAdjustment);
+ }
+}
+
+void VTableBuilder::LayoutVTable() {
+ LayoutPrimaryAndSecondaryVTables(BaseSubobject(MostDerivedClass,
+ CharUnits::Zero()),
+ /*BaseIsMorallyVirtual=*/false,
+ MostDerivedClassIsVirtual,
+ MostDerivedClassOffset);
+
+ VisitedVirtualBasesSetTy VBases;
+
+ // Determine the primary virtual bases.
+ DeterminePrimaryVirtualBases(MostDerivedClass, MostDerivedClassOffset,
+ VBases);
+ VBases.clear();
+
+ LayoutVTablesForVirtualBases(MostDerivedClass, VBases);
+
+ // -fapple-kext adds an extra entry at end of vtbl.
+ bool IsAppleKext = Context.getLangOptions().AppleKext;
+ if (IsAppleKext)
+ Components.push_back(VTableComponent::MakeVCallOffset(CharUnits::Zero()));
+}
+
+void
+VTableBuilder::LayoutPrimaryAndSecondaryVTables(BaseSubobject Base,
+ bool BaseIsMorallyVirtual,
+ bool BaseIsVirtualInLayoutClass,
+ CharUnits OffsetInLayoutClass) {
+ assert(Base.getBase()->isDynamicClass() && "class does not have a vtable!");
+
+ // Add vcall and vbase offsets for this vtable.
+ VCallAndVBaseOffsetBuilder Builder(MostDerivedClass, LayoutClass, &Overriders,
+ Base, BaseIsVirtualInLayoutClass,
+ OffsetInLayoutClass);
+ Components.append(Builder.components_begin(), Builder.components_end());
+
+ // Check if we need to add these vcall offsets.
+ if (BaseIsVirtualInLayoutClass && !Builder.getVCallOffsets().empty()) {
+ VCallOffsetMap &VCallOffsets = VCallOffsetsForVBases[Base.getBase()];
+
+ if (VCallOffsets.empty())
+ VCallOffsets = Builder.getVCallOffsets();
+ }
+
+ // If we're laying out the most derived class we want to keep track of the
+ // virtual base class offset offsets.
+ if (Base.getBase() == MostDerivedClass)
+ VBaseOffsetOffsets = Builder.getVBaseOffsetOffsets();
+
+ // Add the offset to top.
+ CharUnits OffsetToTop = MostDerivedClassOffset - OffsetInLayoutClass;
+ Components.push_back(
+ VTableComponent::MakeOffsetToTop(OffsetToTop));
+
+ // Next, add the RTTI.
+ Components.push_back(VTableComponent::MakeRTTI(MostDerivedClass));
+
+ uint64_t AddressPoint = Components.size();
+
+ // Now go through all virtual member functions and add them.
+ PrimaryBasesSetVectorTy PrimaryBases;
+ AddMethods(Base, OffsetInLayoutClass,
+ Base.getBase(), OffsetInLayoutClass,
+ PrimaryBases);
+
+ // Compute 'this' pointer adjustments.
+ ComputeThisAdjustments();
+
+ // Add all address points.
+ const CXXRecordDecl *RD = Base.getBase();
+ while (true) {
+ AddressPoints.insert(std::make_pair(
+ BaseSubobject(RD, OffsetInLayoutClass),
+ AddressPoint));
+
+ const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
+ const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
+
+ if (!PrimaryBase)
+ break;
+
+ if (Layout.isPrimaryBaseVirtual()) {
+ // Check if this virtual primary base is a primary base in the layout
+ // class. If it's not, we don't want to add it.
+ const ASTRecordLayout &LayoutClassLayout =
+ Context.getASTRecordLayout(LayoutClass);
+
+ if (LayoutClassLayout.getVBaseClassOffset(PrimaryBase) !=
+ OffsetInLayoutClass) {
+ // We don't want to add this class (or any of its primary bases).
+ break;
+ }
+ }
+
+ RD = PrimaryBase;
+ }
+
+ // Layout secondary vtables.
+ LayoutSecondaryVTables(Base, BaseIsMorallyVirtual, OffsetInLayoutClass);
+}
+
+void VTableBuilder::LayoutSecondaryVTables(BaseSubobject Base,
+ bool BaseIsMorallyVirtual,
+ CharUnits OffsetInLayoutClass) {
+ // Itanium C++ ABI 2.5.2:
+ // Following the primary virtual table of a derived class are secondary
+ // virtual tables for each of its proper base classes, except any primary
+ // base(s) with which it shares its primary virtual table.
+
+ const CXXRecordDecl *RD = Base.getBase();
+ const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
+ const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
+
+ for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
+ E = RD->bases_end(); I != E; ++I) {
+ // Ignore virtual bases, we'll emit them later.
+ if (I->isVirtual())
+ continue;
+
+ const CXXRecordDecl *BaseDecl =
+ cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
+
+ // Ignore bases that don't have a vtable.
+ if (!BaseDecl->isDynamicClass())
+ continue;
+
+ if (isBuildingConstructorVTable()) {
+ // Itanium C++ ABI 2.6.4:
+ // Some of the base class subobjects may not need construction virtual
+ // tables, which will therefore not be present in the construction
+ // virtual table group, even though the subobject virtual tables are
+ // present in the main virtual table group for the complete object.
+ if (!BaseIsMorallyVirtual && !BaseDecl->getNumVBases())
+ continue;
+ }
+
+ // Get the base offset of this base.
+ CharUnits RelativeBaseOffset = Layout.getBaseClassOffset(BaseDecl);
+ CharUnits BaseOffset = Base.getBaseOffset() + RelativeBaseOffset;
+
+ CharUnits BaseOffsetInLayoutClass =
+ OffsetInLayoutClass + RelativeBaseOffset;
+
+ // Don't emit a secondary vtable for a primary base. We might however want
+ // to emit secondary vtables for other bases of this base.
+ if (BaseDecl == PrimaryBase) {
+ LayoutSecondaryVTables(BaseSubobject(BaseDecl, BaseOffset),
+ BaseIsMorallyVirtual, BaseOffsetInLayoutClass);
+ continue;
+ }
+
+ // Layout the primary vtable (and any secondary vtables) for this base.
+ LayoutPrimaryAndSecondaryVTables(
+ BaseSubobject(BaseDecl, BaseOffset),
+ BaseIsMorallyVirtual,
+ /*BaseIsVirtualInLayoutClass=*/false,
+ BaseOffsetInLayoutClass);
+ }
+}
+
+void
+VTableBuilder::DeterminePrimaryVirtualBases(const CXXRecordDecl *RD,
+ CharUnits OffsetInLayoutClass,
+ VisitedVirtualBasesSetTy &VBases) {
+ const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
+
+ // Check if this base has a primary base.
+ if (const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase()) {
+
+ // Check if it's virtual.
+ if (Layout.isPrimaryBaseVirtual()) {
+ bool IsPrimaryVirtualBase = true;
+
+ if (isBuildingConstructorVTable()) {
+ // Check if the base is actually a primary base in the class we use for
+ // layout.
+ const ASTRecordLayout &LayoutClassLayout =
+ Context.getASTRecordLayout(LayoutClass);
+
+ CharUnits PrimaryBaseOffsetInLayoutClass =
+ LayoutClassLayout.getVBaseClassOffset(PrimaryBase);
+
+ // We know that the base is not a primary base in the layout class if
+ // the base offsets are different.
+ if (PrimaryBaseOffsetInLayoutClass != OffsetInLayoutClass)
+ IsPrimaryVirtualBase = false;
+ }
+
+ if (IsPrimaryVirtualBase)
+ PrimaryVirtualBases.insert(PrimaryBase);
+ }
+ }
+
+ // Traverse bases, looking for more primary virtual bases.
+ for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
+ E = RD->bases_end(); I != E; ++I) {
+ const CXXRecordDecl *BaseDecl =
+ cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
+
+ CharUnits BaseOffsetInLayoutClass;
+
+ if (I->isVirtual()) {
+ if (!VBases.insert(BaseDecl))
+ continue;
+
+ const ASTRecordLayout &LayoutClassLayout =
+ Context.getASTRecordLayout(LayoutClass);
+
+ BaseOffsetInLayoutClass =
+ LayoutClassLayout.getVBaseClassOffset(BaseDecl);
+ } else {
+ BaseOffsetInLayoutClass =
+ OffsetInLayoutClass + Layout.getBaseClassOffset(BaseDecl);
+ }
+
+ DeterminePrimaryVirtualBases(BaseDecl, BaseOffsetInLayoutClass, VBases);
+ }
+}
+
+void
+VTableBuilder::LayoutVTablesForVirtualBases(const CXXRecordDecl *RD,
+ VisitedVirtualBasesSetTy &VBases) {
+ // Itanium C++ ABI 2.5.2:
+ // Then come the virtual base virtual tables, also in inheritance graph
+ // order, and again excluding primary bases (which share virtual tables with
+ // the classes for which they are primary).
+ for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
+ E = RD->bases_end(); I != E; ++I) {
+ const CXXRecordDecl *BaseDecl =
+ cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
+
+ // Check if this base needs a vtable. (If it's virtual, not a primary base
+ // of some other class, and we haven't visited it before).
+ if (I->isVirtual() && BaseDecl->isDynamicClass() &&
+ !PrimaryVirtualBases.count(BaseDecl) && VBases.insert(BaseDecl)) {
+ const ASTRecordLayout &MostDerivedClassLayout =
+ Context.getASTRecordLayout(MostDerivedClass);
+ CharUnits BaseOffset =
+ MostDerivedClassLayout.getVBaseClassOffset(BaseDecl);
+
+ const ASTRecordLayout &LayoutClassLayout =
+ Context.getASTRecordLayout(LayoutClass);
+ CharUnits BaseOffsetInLayoutClass =
+ LayoutClassLayout.getVBaseClassOffset(BaseDecl);
+
+ LayoutPrimaryAndSecondaryVTables(
+ BaseSubobject(BaseDecl, BaseOffset),
+ /*BaseIsMorallyVirtual=*/true,
+ /*BaseIsVirtualInLayoutClass=*/true,
+ BaseOffsetInLayoutClass);
+ }
+
+ // We only need to check the base for virtual base vtables if it actually
+ // has virtual bases.
+ if (BaseDecl->getNumVBases())
+ LayoutVTablesForVirtualBases(BaseDecl, VBases);
+ }
+}
+
+/// dumpLayout - Dump the vtable layout.
+void VTableBuilder::dumpLayout(raw_ostream& Out) {
+
+ if (isBuildingConstructorVTable()) {
+ Out << "Construction vtable for ('";
+ Out << MostDerivedClass->getQualifiedNameAsString() << "', ";
+ Out << MostDerivedClassOffset.getQuantity() << ") in '";
+ Out << LayoutClass->getQualifiedNameAsString();
+ } else {
+ Out << "Vtable for '";
+ Out << MostDerivedClass->getQualifiedNameAsString();
+ }
+ Out << "' (" << Components.size() << " entries).\n";
+
+ // Iterate through the address points and insert them into a new map where
+ // they are keyed by the index and not the base object.
+ // Since an address point can be shared by multiple subobjects, we use an
+ // STL multimap.
+ std::multimap<uint64_t, BaseSubobject> AddressPointsByIndex;
+ for (AddressPointsMapTy::const_iterator I = AddressPoints.begin(),
+ E = AddressPoints.end(); I != E; ++I) {
+ const BaseSubobject& Base = I->first;
+ uint64_t Index = I->second;
+
+ AddressPointsByIndex.insert(std::make_pair(Index, Base));
+ }
+
+ for (unsigned I = 0, E = Components.size(); I != E; ++I) {
+ uint64_t Index = I;
+
+ Out << llvm::format("%4d | ", I);
+
+ const VTableComponent &Component = Components[I];
+
+ // Dump the component.
+ switch (Component.getKind()) {
+
+ case VTableComponent::CK_VCallOffset:
+ Out << "vcall_offset ("
+ << Component.getVCallOffset().getQuantity()
+ << ")";
+ break;
+
+ case VTableComponent::CK_VBaseOffset:
+ Out << "vbase_offset ("
+ << Component.getVBaseOffset().getQuantity()
+ << ")";
+ break;
+
+ case VTableComponent::CK_OffsetToTop:
+ Out << "offset_to_top ("
+ << Component.getOffsetToTop().getQuantity()
+ << ")";
+ break;
+
+ case VTableComponent::CK_RTTI:
+ Out << Component.getRTTIDecl()->getQualifiedNameAsString() << " RTTI";
+ break;
+
+ case VTableComponent::CK_FunctionPointer: {
+ const CXXMethodDecl *MD = Component.getFunctionDecl();
+
+ std::string Str =
+ PredefinedExpr::ComputeName(PredefinedExpr::PrettyFunctionNoVirtual,
+ MD);
+ Out << Str;
+ if (MD->isPure())
+ Out << " [pure]";
+
+ ThunkInfo Thunk = VTableThunks.lookup(I);
+ if (!Thunk.isEmpty()) {
+ // If this function pointer has a return adjustment, dump it.
+ if (!Thunk.Return.isEmpty()) {
+ Out << "\n [return adjustment: ";
+ Out << Thunk.Return.NonVirtual << " non-virtual";
+
+ if (Thunk.Return.VBaseOffsetOffset) {
+ Out << ", " << Thunk.Return.VBaseOffsetOffset;
+ Out << " vbase offset offset";
+ }
+
+ Out << ']';
+ }
+
+ // If this function pointer has a 'this' pointer adjustment, dump it.
+ if (!Thunk.This.isEmpty()) {
+ Out << "\n [this adjustment: ";
+ Out << Thunk.This.NonVirtual << " non-virtual";
+
+ if (Thunk.This.VCallOffsetOffset) {
+ Out << ", " << Thunk.This.VCallOffsetOffset;
+ Out << " vcall offset offset";
+ }
+
+ Out << ']';
+ }
+ }
+
+ break;
+ }
+
+ case VTableComponent::CK_CompleteDtorPointer:
+ case VTableComponent::CK_DeletingDtorPointer: {
+ bool IsComplete =
+ Component.getKind() == VTableComponent::CK_CompleteDtorPointer;
+
+ const CXXDestructorDecl *DD = Component.getDestructorDecl();
+
+ Out << DD->getQualifiedNameAsString();
+ if (IsComplete)
+ Out << "() [complete]";
+ else
+ Out << "() [deleting]";
+
+ if (DD->isPure())
+ Out << " [pure]";
+
+ ThunkInfo Thunk = VTableThunks.lookup(I);
+ if (!Thunk.isEmpty()) {
+ // If this destructor has a 'this' pointer adjustment, dump it.
+ if (!Thunk.This.isEmpty()) {
+ Out << "\n [this adjustment: ";
+ Out << Thunk.This.NonVirtual << " non-virtual";
+
+ if (Thunk.This.VCallOffsetOffset) {
+ Out << ", " << Thunk.This.VCallOffsetOffset;
+ Out << " vcall offset offset";
+ }
+
+ Out << ']';
+ }
+ }
+
+ break;
+ }
+
+ case VTableComponent::CK_UnusedFunctionPointer: {
+ const CXXMethodDecl *MD = Component.getUnusedFunctionDecl();
+
+ std::string Str =
+ PredefinedExpr::ComputeName(PredefinedExpr::PrettyFunctionNoVirtual,
+ MD);
+ Out << "[unused] " << Str;
+ if (MD->isPure())
+ Out << " [pure]";
+ }
+
+ }
+
+ Out << '\n';
+
+ // Dump the next address point.
+ uint64_t NextIndex = Index + 1;
+ if (AddressPointsByIndex.count(NextIndex)) {
+ if (AddressPointsByIndex.count(NextIndex) == 1) {
+ const BaseSubobject &Base =
+ AddressPointsByIndex.find(NextIndex)->second;
+
+ Out << " -- (" << Base.getBase()->getQualifiedNameAsString();
+ Out << ", " << Base.getBaseOffset().getQuantity();
+ Out << ") vtable address --\n";
+ } else {
+ CharUnits BaseOffset =
+ AddressPointsByIndex.lower_bound(NextIndex)->second.getBaseOffset();
+
+ // We store the class names in a set to get a stable order.
+ std::set<std::string> ClassNames;
+ for (std::multimap<uint64_t, BaseSubobject>::const_iterator I =
+ AddressPointsByIndex.lower_bound(NextIndex), E =
+ AddressPointsByIndex.upper_bound(NextIndex); I != E; ++I) {
+ assert(I->second.getBaseOffset() == BaseOffset &&
+ "Invalid base offset!");
+ const CXXRecordDecl *RD = I->second.getBase();
+ ClassNames.insert(RD->getQualifiedNameAsString());
+ }
+
+ for (std::set<std::string>::const_iterator I = ClassNames.begin(),
+ E = ClassNames.end(); I != E; ++I) {
+ Out << " -- (" << *I;
+ Out << ", " << BaseOffset.getQuantity() << ") vtable address --\n";
+ }
+ }
+ }
+ }
+
+ Out << '\n';
+
+ if (isBuildingConstructorVTable())
+ return;
+
+ if (MostDerivedClass->getNumVBases()) {
+ // We store the virtual base class names and their offsets in a map to get
+ // a stable order.
+
+ std::map<std::string, CharUnits> ClassNamesAndOffsets;
+ for (VBaseOffsetOffsetsMapTy::const_iterator I = VBaseOffsetOffsets.begin(),
+ E = VBaseOffsetOffsets.end(); I != E; ++I) {
+ std::string ClassName = I->first->getQualifiedNameAsString();
+ CharUnits OffsetOffset = I->second;
+ ClassNamesAndOffsets.insert(
+ std::make_pair(ClassName, OffsetOffset));
+ }
+
+ Out << "Virtual base offset offsets for '";
+ Out << MostDerivedClass->getQualifiedNameAsString() << "' (";
+ Out << ClassNamesAndOffsets.size();
+ Out << (ClassNamesAndOffsets.size() == 1 ? " entry" : " entries") << ").\n";
+
+ for (std::map<std::string, CharUnits>::const_iterator I =
+ ClassNamesAndOffsets.begin(), E = ClassNamesAndOffsets.end();
+ I != E; ++I)
+ Out << " " << I->first << " | " << I->second.getQuantity() << '\n';
+
+ Out << "\n";
+ }
+
+ if (!Thunks.empty()) {
+ // We store the method names in a map to get a stable order.
+ std::map<std::string, const CXXMethodDecl *> MethodNamesAndDecls;
+
+ for (ThunksMapTy::const_iterator I = Thunks.begin(), E = Thunks.end();
+ I != E; ++I) {
+ const CXXMethodDecl *MD = I->first;
+ std::string MethodName =
+ PredefinedExpr::ComputeName(PredefinedExpr::PrettyFunctionNoVirtual,
+ MD);
+
+ MethodNamesAndDecls.insert(std::make_pair(MethodName, MD));
+ }
+
+ for (std::map<std::string, const CXXMethodDecl *>::const_iterator I =
+ MethodNamesAndDecls.begin(), E = MethodNamesAndDecls.end();
+ I != E; ++I) {
+ const std::string &MethodName = I->first;
+ const CXXMethodDecl *MD = I->second;
+
+ ThunkInfoVectorTy ThunksVector = Thunks[MD];
+ std::sort(ThunksVector.begin(), ThunksVector.end());
+
+ Out << "Thunks for '" << MethodName << "' (" << ThunksVector.size();
+ Out << (ThunksVector.size() == 1 ? " entry" : " entries") << ").\n";
+
+ for (unsigned I = 0, E = ThunksVector.size(); I != E; ++I) {
+ const ThunkInfo &Thunk = ThunksVector[I];
+
+ Out << llvm::format("%4d | ", I);
+
+ // If this function pointer has a return pointer adjustment, dump it.
+ if (!Thunk.Return.isEmpty()) {
+ Out << "return adjustment: " << Thunk.This.NonVirtual;
+ Out << " non-virtual";
+ if (Thunk.Return.VBaseOffsetOffset) {
+ Out << ", " << Thunk.Return.VBaseOffsetOffset;
+ Out << " vbase offset offset";
+ }
+
+ if (!Thunk.This.isEmpty())
+ Out << "\n ";
+ }
+
+ // If this function pointer has a 'this' pointer adjustment, dump it.
+ if (!Thunk.This.isEmpty()) {
+ Out << "this adjustment: ";
+ Out << Thunk.This.NonVirtual << " non-virtual";
+
+ if (Thunk.This.VCallOffsetOffset) {
+ Out << ", " << Thunk.This.VCallOffsetOffset;
+ Out << " vcall offset offset";
+ }
+ }
+
+ Out << '\n';
+ }
+
+ Out << '\n';
+ }
+ }
+
+ // Compute the vtable indices for all the member functions.
+ // Store them in a map keyed by the index so we'll get a sorted table.
+ std::map<uint64_t, std::string> IndicesMap;
+
+ for (CXXRecordDecl::method_iterator i = MostDerivedClass->method_begin(),
+ e = MostDerivedClass->method_end(); i != e; ++i) {
+ const CXXMethodDecl *MD = *i;
+
+ // We only want virtual member functions.
+ if (!MD->isVirtual())
+ continue;
+
+ std::string MethodName =
+ PredefinedExpr::ComputeName(PredefinedExpr::PrettyFunctionNoVirtual,
+ MD);
+
+ if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
+ IndicesMap[VTables.getMethodVTableIndex(GlobalDecl(DD, Dtor_Complete))] =
+ MethodName + " [complete]";
+ IndicesMap[VTables.getMethodVTableIndex(GlobalDecl(DD, Dtor_Deleting))] =
+ MethodName + " [deleting]";
+ } else {
+ IndicesMap[VTables.getMethodVTableIndex(MD)] = MethodName;
+ }
+ }
+
+ // Print the vtable indices for all the member functions.
+ if (!IndicesMap.empty()) {
+ Out << "VTable indices for '";
+ Out << MostDerivedClass->getQualifiedNameAsString();
+ Out << "' (" << IndicesMap.size() << " entries).\n";
+
+ for (std::map<uint64_t, std::string>::const_iterator I = IndicesMap.begin(),
+ E = IndicesMap.end(); I != E; ++I) {
+ uint64_t VTableIndex = I->first;
+ const std::string &MethodName = I->second;
+
+ Out << llvm::format(" %4u | ", VTableIndex) << MethodName << '\n';
+ }
+ }
+
+ Out << '\n';
+}
+
+}
+
+VTableLayout::VTableLayout(uint64_t NumVTableComponents,
+ const VTableComponent *VTableComponents,
+ uint64_t NumVTableThunks,
+ const VTableThunkTy *VTableThunks,
+ const AddressPointsMapTy &AddressPoints)
+ : NumVTableComponents(NumVTableComponents),
+ VTableComponents(new VTableComponent[NumVTableComponents]),
+ NumVTableThunks(NumVTableThunks),
+ VTableThunks(new VTableThunkTy[NumVTableThunks]),
+ AddressPoints(AddressPoints) {
+ std::copy(VTableComponents, VTableComponents+NumVTableComponents,
+ this->VTableComponents);
+ std::copy(VTableThunks, VTableThunks+NumVTableThunks, this->VTableThunks);
+}
+
+VTableLayout::~VTableLayout() {
+ delete[] VTableComponents;
+}
+
+VTableContext::~VTableContext() {
+ llvm::DeleteContainerSeconds(VTableLayouts);
+}
+
+static void
+CollectPrimaryBases(const CXXRecordDecl *RD, ASTContext &Context,
+ VTableBuilder::PrimaryBasesSetVectorTy &PrimaryBases) {
+ const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
+ const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
+
+ if (!PrimaryBase)
+ return;
+
+ CollectPrimaryBases(PrimaryBase, Context, PrimaryBases);
+
+ if (!PrimaryBases.insert(PrimaryBase))
+ llvm_unreachable("Found a duplicate primary base!");
+}
+
+void VTableContext::ComputeMethodVTableIndices(const CXXRecordDecl *RD) {
+
+ // Itanium C++ ABI 2.5.2:
+ // The order of the virtual function pointers in a virtual table is the
+ // order of declaration of the corresponding member functions in the class.
+ //
+ // There is an entry for any virtual function declared in a class,
+ // whether it is a new function or overrides a base class function,
+ // unless it overrides a function from the primary base, and conversion
+ // between their return types does not require an adjustment.
+
+ int64_t CurrentIndex = 0;
+
+ const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
+ const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
+
+ if (PrimaryBase) {
+ assert(PrimaryBase->isDefinition() &&
+ "Should have the definition decl of the primary base!");
+
+ // Since the record decl shares its vtable pointer with the primary base
+ // we need to start counting at the end of the primary base's vtable.
+ CurrentIndex = getNumVirtualFunctionPointers(PrimaryBase);
+ }
+
+ // Collect all the primary bases, so we can check whether methods override
+ // a method from the base.
+ VTableBuilder::PrimaryBasesSetVectorTy PrimaryBases;
+ CollectPrimaryBases(RD, Context, PrimaryBases);
+
+ const CXXDestructorDecl *ImplicitVirtualDtor = 0;
+
+ for (CXXRecordDecl::method_iterator i = RD->method_begin(),
+ e = RD->method_end(); i != e; ++i) {
+ const CXXMethodDecl *MD = *i;
+
+ // We only want virtual methods.
+ if (!MD->isVirtual())
+ continue;
+
+ // Check if this method overrides a method in the primary base.
+ if (const CXXMethodDecl *OverriddenMD =
+ FindNearestOverriddenMethod(MD, PrimaryBases)) {
+ // Check if converting from the return type of the method to the
+ // return type of the overridden method requires conversion.
+ if (ComputeReturnAdjustmentBaseOffset(Context, MD,
+ OverriddenMD).isEmpty()) {
+ // This index is shared between the index in the vtable of the primary
+ // base class.
+ if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
+ const CXXDestructorDecl *OverriddenDD =
+ cast<CXXDestructorDecl>(OverriddenMD);
+
+ // Add both the complete and deleting entries.
+ MethodVTableIndices[GlobalDecl(DD, Dtor_Complete)] =
+ getMethodVTableIndex(GlobalDecl(OverriddenDD, Dtor_Complete));
+ MethodVTableIndices[GlobalDecl(DD, Dtor_Deleting)] =
+ getMethodVTableIndex(GlobalDecl(OverriddenDD, Dtor_Deleting));
+ } else {
+ MethodVTableIndices[MD] = getMethodVTableIndex(OverriddenMD);
+ }
+
+ // We don't need to add an entry for this method.
+ continue;
+ }
+ }
+
+ if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
+ if (MD->isImplicit()) {
+ assert(!ImplicitVirtualDtor &&
+ "Did already see an implicit virtual dtor!");
+ ImplicitVirtualDtor = DD;
+ continue;
+ }
+
+ // Add the complete dtor.
+ MethodVTableIndices[GlobalDecl(DD, Dtor_Complete)] = CurrentIndex++;
+
+ // Add the deleting dtor.
+ MethodVTableIndices[GlobalDecl(DD, Dtor_Deleting)] = CurrentIndex++;
+ } else {
+ // Add the entry.
+ MethodVTableIndices[MD] = CurrentIndex++;
+ }
+ }
+
+ if (ImplicitVirtualDtor) {
+ // Itanium C++ ABI 2.5.2:
+ // If a class has an implicitly-defined virtual destructor,
+ // its entries come after the declared virtual function pointers.
+
+ // Add the complete dtor.
+ MethodVTableIndices[GlobalDecl(ImplicitVirtualDtor, Dtor_Complete)] =
+ CurrentIndex++;
+
+ // Add the deleting dtor.
+ MethodVTableIndices[GlobalDecl(ImplicitVirtualDtor, Dtor_Deleting)] =
+ CurrentIndex++;
+ }
+
+ NumVirtualFunctionPointers[RD] = CurrentIndex;
+}
+
+uint64_t VTableContext::getNumVirtualFunctionPointers(const CXXRecordDecl *RD) {
+ llvm::DenseMap<const CXXRecordDecl *, uint64_t>::iterator I =
+ NumVirtualFunctionPointers.find(RD);
+ if (I != NumVirtualFunctionPointers.end())
+ return I->second;
+
+ ComputeMethodVTableIndices(RD);
+
+ I = NumVirtualFunctionPointers.find(RD);
+ assert(I != NumVirtualFunctionPointers.end() && "Did not find entry!");
+ return I->second;
+}
+
+uint64_t VTableContext::getMethodVTableIndex(GlobalDecl GD) {
+ MethodVTableIndicesTy::iterator I = MethodVTableIndices.find(GD);
+ if (I != MethodVTableIndices.end())
+ return I->second;
+
+ const CXXRecordDecl *RD = cast<CXXMethodDecl>(GD.getDecl())->getParent();
+
+ ComputeMethodVTableIndices(RD);
+
+ I = MethodVTableIndices.find(GD);
+ assert(I != MethodVTableIndices.end() && "Did not find index!");
+ return I->second;
+}
+
+CharUnits
+VTableContext::getVirtualBaseOffsetOffset(const CXXRecordDecl *RD,
+ const CXXRecordDecl *VBase) {
+ ClassPairTy ClassPair(RD, VBase);
+
+ VirtualBaseClassOffsetOffsetsMapTy::iterator I =
+ VirtualBaseClassOffsetOffsets.find(ClassPair);
+ if (I != VirtualBaseClassOffsetOffsets.end())
+ return I->second;
+
+ VCallAndVBaseOffsetBuilder Builder(RD, RD, /*FinalOverriders=*/0,
+ BaseSubobject(RD, CharUnits::Zero()),
+ /*BaseIsVirtual=*/false,
+ /*OffsetInLayoutClass=*/CharUnits::Zero());
+
+ for (VCallAndVBaseOffsetBuilder::VBaseOffsetOffsetsMapTy::const_iterator I =
+ Builder.getVBaseOffsetOffsets().begin(),
+ E = Builder.getVBaseOffsetOffsets().end(); I != E; ++I) {
+ // Insert all types.
+ ClassPairTy ClassPair(RD, I->first);
+
+ VirtualBaseClassOffsetOffsets.insert(
+ std::make_pair(ClassPair, I->second));
+ }
+
+ I = VirtualBaseClassOffsetOffsets.find(ClassPair);
+ assert(I != VirtualBaseClassOffsetOffsets.end() && "Did not find index!");
+
+ return I->second;
+}
+
+static VTableLayout *CreateVTableLayout(const VTableBuilder &Builder) {
+ SmallVector<VTableLayout::VTableThunkTy, 1>
+ VTableThunks(Builder.vtable_thunks_begin(), Builder.vtable_thunks_end());
+ std::sort(VTableThunks.begin(), VTableThunks.end());
+
+ return new VTableLayout(Builder.getNumVTableComponents(),
+ Builder.vtable_component_begin(),
+ VTableThunks.size(),
+ VTableThunks.data(),
+ Builder.getAddressPoints());
+}
+
+void VTableContext::ComputeVTableRelatedInformation(const CXXRecordDecl *RD) {
+ const VTableLayout *&Entry = VTableLayouts[RD];
+
+ // Check if we've computed this information before.
+ if (Entry)
+ return;
+
+ VTableBuilder Builder(*this, RD, CharUnits::Zero(),
+ /*MostDerivedClassIsVirtual=*/0, RD);
+ Entry = CreateVTableLayout(Builder);
+
+ // Add the known thunks.
+ Thunks.insert(Builder.thunks_begin(), Builder.thunks_end());
+
+ // If we don't have the vbase information for this class, insert it.
+ // getVirtualBaseOffsetOffset will compute it separately without computing
+ // the rest of the vtable related information.
+ if (!RD->getNumVBases())
+ return;
+
+ const RecordType *VBaseRT =
+ RD->vbases_begin()->getType()->getAs<RecordType>();
+ const CXXRecordDecl *VBase = cast<CXXRecordDecl>(VBaseRT->getDecl());
+
+ if (VirtualBaseClassOffsetOffsets.count(std::make_pair(RD, VBase)))
+ return;
+
+ for (VTableBuilder::VBaseOffsetOffsetsMapTy::const_iterator I =
+ Builder.getVBaseOffsetOffsets().begin(),
+ E = Builder.getVBaseOffsetOffsets().end(); I != E; ++I) {
+ // Insert all types.
+ ClassPairTy ClassPair(RD, I->first);
+
+ VirtualBaseClassOffsetOffsets.insert(std::make_pair(ClassPair, I->second));
+ }
+}
+
+VTableLayout *VTableContext::createConstructionVTableLayout(
+ const CXXRecordDecl *MostDerivedClass,
+ CharUnits MostDerivedClassOffset,
+ bool MostDerivedClassIsVirtual,
+ const CXXRecordDecl *LayoutClass) {
+ VTableBuilder Builder(*this, MostDerivedClass, MostDerivedClassOffset,
+ MostDerivedClassIsVirtual, LayoutClass);
+ return CreateVTableLayout(Builder);
+}