diff options
| -rw-r--r-- | clang/lib/AST/RecordLayoutBuilder.cpp | 176 |
1 files changed, 169 insertions, 7 deletions
diff --git a/clang/lib/AST/RecordLayoutBuilder.cpp b/clang/lib/AST/RecordLayoutBuilder.cpp index 56a152a0b9f..df7ed57a580 100644 --- a/clang/lib/AST/RecordLayoutBuilder.cpp +++ b/clang/lib/AST/RecordLayoutBuilder.cpp @@ -31,10 +31,35 @@ class EmptySubobjectMap { /// Class - The class whose empty entries we're keeping track of. const CXXRecordDecl *Class; + /// EmptyClassOffsets - A map from offsets to empty record decls. + typedef llvm::SmallVector<const CXXRecordDecl *, 1> ClassVectorTy; + typedef llvm::DenseMap<uint64_t, ClassVectorTy> EmptyClassOffsetsMapTy; + EmptyClassOffsetsMapTy EmptyClassOffsets; + /// ComputeEmptySubobjectSizes - Compute the size of the largest base or /// member subobject that is empty. void ComputeEmptySubobjectSizes(); + struct BaseInfo { + const CXXRecordDecl *Class; + bool IsVirtual; + + const CXXRecordDecl *PrimaryVirtualBase; + + llvm::SmallVector<BaseInfo*, 4> Bases; + const BaseInfo *Derived; + }; + + llvm::DenseMap<const CXXRecordDecl *, BaseInfo *> VirtualBaseInfo; + llvm::DenseMap<const CXXRecordDecl *, BaseInfo *> NonVirtualBaseInfo; + + BaseInfo *ComputeBaseInfo(const CXXRecordDecl *RD, bool IsVirtual, + const BaseInfo *Derived); + void ComputeBaseInfo(); + + bool CanPlaceBaseSubobjectAtOffset(const BaseInfo *Info, uint64_t Offset); + void UpdateEmptyBaseSubobjects(const BaseInfo *Info, uint64_t Offset); + public: /// This holds the size of the largest empty subobject (either a base /// or a member). Will be zero if the record being built doesn't contain @@ -44,6 +69,8 @@ public: EmptySubobjectMap(ASTContext &Context, const CXXRecordDecl *Class) : Context(Context), Class(Class), SizeOfLargestEmptySubobject(0) { ComputeEmptySubobjectSizes(); + + ComputeBaseInfo(); } /// CanPlaceBaseAtOffset - Return whether the given base class can be placed @@ -103,15 +130,153 @@ void EmptySubobjectMap::ComputeEmptySubobjectSizes() { } } +EmptySubobjectMap::BaseInfo * +EmptySubobjectMap::ComputeBaseInfo(const CXXRecordDecl *RD, bool IsVirtual, + const BaseInfo *Derived) { + BaseInfo *Info; + + if (IsVirtual) { + BaseInfo *&InfoSlot = VirtualBaseInfo[RD]; + if (InfoSlot) { + assert(InfoSlot->Class == RD && "Wrong class for virtual base info!"); + return InfoSlot; + } + + InfoSlot = new (Context) BaseInfo; + Info = InfoSlot; + } else { + Info = new (Context) BaseInfo; + } + + Info->Class = RD; + Info->IsVirtual = IsVirtual; + Info->Derived = Derived; + Info->PrimaryVirtualBase = 0; + + if (RD->getNumVBases()) { + // Check if this class has a primary virtual base. + const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD); + if (Layout.getPrimaryBaseWasVirtual()) { + Info->PrimaryVirtualBase = Layout.getPrimaryBase(); + assert(Info->PrimaryVirtualBase && + "Didn't have a primary virtual base!"); + } + } + + for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(), + E = RD->bases_end(); I != E; ++I) { + bool IsVirtual = I->isVirtual(); + + const CXXRecordDecl *BaseDecl = + cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl()); + + Info->Bases.push_back(ComputeBaseInfo(BaseDecl, IsVirtual, Info)); + } + + return Info; +} + +void EmptySubobjectMap::ComputeBaseInfo() { + for (CXXRecordDecl::base_class_const_iterator I = Class->bases_begin(), + E = Class->bases_end(); I != E; ++I) { + bool IsVirtual = I->isVirtual(); + + const CXXRecordDecl *BaseDecl = + cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl()); + + BaseInfo *Info = ComputeBaseInfo(BaseDecl, IsVirtual, /*Derived=*/0); + if (IsVirtual) { + // ComputeBaseInfo has already added this base for us. + continue; + } + + // Add the base info to the map of non-virtual bases. + assert(!NonVirtualBaseInfo.count(BaseDecl) && + "Non-virtual base already exists!"); + NonVirtualBaseInfo.insert(std::make_pair(BaseDecl, Info)); + } +} + bool -EmptySubobjectMap::CanPlaceBaseAtOffset(const CXXRecordDecl *RD, - bool BaseIsVirtual, - uint64_t Offset) { +EmptySubobjectMap::CanPlaceBaseSubobjectAtOffset(const BaseInfo *Info, + uint64_t Offset) { + // Traverse all non-virtual bases. + for (unsigned I = 0, E = Info->Bases.size(); I != E; ++I) { + BaseInfo* Base = Info->Bases[I]; + if (Base->IsVirtual) + continue; + + const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class); + uint64_t BaseOffset = Offset + Layout.getBaseClassOffset(Base->Class); + + if (!CanPlaceBaseSubobjectAtOffset(Base, BaseOffset)) + return false; + } + + if (Info->PrimaryVirtualBase) { + BaseInfo *PrimaryVirtualBaseInfo = + VirtualBaseInfo.lookup(Info->PrimaryVirtualBase); + assert(PrimaryVirtualBaseInfo && "Didn't find base info!"); + + if (Info == PrimaryVirtualBaseInfo->Derived) { + if (!CanPlaceBaseSubobjectAtOffset(PrimaryVirtualBaseInfo, Offset)) + return false; + } + } + + // FIXME: Member variables. + return true; +} + +void EmptySubobjectMap::UpdateEmptyBaseSubobjects(const BaseInfo *Info, + uint64_t Offset) { + if (Info->Class->isEmpty()) { + // FIXME: Record that there is an empty class at this offset. + } + + // Traverse all non-virtual bases. + for (unsigned I = 0, E = Info->Bases.size(); I != E; ++I) { + BaseInfo* Base = Info->Bases[I]; + if (Base->IsVirtual) + continue; + + const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class); + uint64_t BaseOffset = Offset + Layout.getBaseClassOffset(Base->Class); + + UpdateEmptyBaseSubobjects(Base, BaseOffset); + } + + if (Info->PrimaryVirtualBase) { + BaseInfo *PrimaryVirtualBaseInfo = + VirtualBaseInfo.lookup(Info->PrimaryVirtualBase); + assert(PrimaryVirtualBaseInfo && "Didn't find base info!"); + + if (Info == PrimaryVirtualBaseInfo->Derived) + UpdateEmptyBaseSubobjects(PrimaryVirtualBaseInfo, Offset); + } + + // FIXME: Member variables. +} + +bool EmptySubobjectMap::CanPlaceBaseAtOffset(const CXXRecordDecl *RD, + bool BaseIsVirtual, + uint64_t Offset) { // If we know this class doesn't have any empty subobjects we don't need to // bother checking. if (!SizeOfLargestEmptySubobject) return true; + BaseInfo *Info; + + if (BaseIsVirtual) + Info = VirtualBaseInfo.lookup(RD); + else + Info = NonVirtualBaseInfo.lookup(RD); + + if (!CanPlaceBaseSubobjectAtOffset(Info, Offset)) + return false; + + UpdateEmptyBaseSubobjects(Info, Offset); return true; } @@ -799,10 +964,6 @@ void RecordLayoutBuilder::Layout(const RecordDecl *D) { } void RecordLayoutBuilder::Layout(const CXXRecordDecl *RD) { - // Create our empty subobject offset map. - EmptySubobjectMap EmptySubobjectMap(Context, RD); - EmptySubobjects = &EmptySubobjectMap; - InitializeLayout(RD); // Lay out the vtable and the non-virtual bases. @@ -1145,6 +1306,7 @@ const ASTRecordLayout &ASTContext::getASTRecordLayout(const RecordDecl *D) { if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D)) { EmptySubobjectMap EmptySubobjects(*this, RD); + RecordLayoutBuilder Builder(*this, &EmptySubobjects); Builder.Layout(RD); |
