1 files changed, 827 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/CodeGen/CGRTTI.cpp b/contrib/llvm/tools/clang/lib/CodeGen/CGRTTI.cpp
new file mode 100644
index 0000000..aec1c45
--- /dev/null
+++ b/contrib/llvm/tools/clang/lib/CodeGen/CGRTTI.cpp
@@ -0,0 +1,827 @@
+//===--- CGCXXRTTI.cpp - Emit LLVM Code for C++ RTTI descriptors ----------===//
+//
+//                     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 C++ code generation of RTTI descriptors.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/AST/Type.h"
+#include "clang/AST/RecordLayout.h"
+#include "CodeGenModule.h"
+using namespace clang;
+using namespace CodeGen;
+
+namespace {
+class RTTIBuilder {
+  CodeGenModule &CGM;  // Per-module state.
+  llvm::LLVMContext &VMContext;
+  
+  const llvm::Type *Int8PtrTy;
+  
+  /// Fields - The fields of the RTTI descriptor currently being built.
+  llvm::SmallVector<llvm::Constant *, 16> Fields;
+
+  /// GetAddrOfExternalRTTIDescriptor - Returns the constant for the RTTI 
+  /// descriptor of the given type.
+  llvm::Constant *GetAddrOfExternalRTTIDescriptor(QualType Ty);
+  
+  /// BuildVTablePointer - Build the vtable pointer for the given type.
+  void BuildVTablePointer(const Type *Ty);
+  
+  /// BuildSIClassTypeInfo - Build an abi::__si_class_type_info, used for single
+  /// inheritance, according to the Itanium C++ ABI, 2.9.5p6b.
+  void BuildSIClassTypeInfo(const CXXRecordDecl *RD);
+  
+  /// BuildVMIClassTypeInfo - Build an abi::__vmi_class_type_info, used for
+  /// classes with bases that do not satisfy the abi::__si_class_type_info 
+  /// constraints, according ti the Itanium C++ ABI, 2.9.5p5c.
+  void BuildVMIClassTypeInfo(const CXXRecordDecl *RD);
+  
+  /// BuildPointerTypeInfo - Build an abi::__pointer_type_info struct, used
+  /// for pointer types.
+  void BuildPointerTypeInfo(const PointerType *Ty);
+  
+  /// BuildPointerToMemberTypeInfo - Build an abi::__pointer_to_member_type_info 
+  /// struct, used for member pointer types.
+  void BuildPointerToMemberTypeInfo(const MemberPointerType *Ty);
+  
+public:
+  RTTIBuilder(CodeGenModule &cgm)
+    : CGM(cgm), VMContext(cgm.getModule().getContext()),
+      Int8PtrTy(llvm::Type::getInt8PtrTy(VMContext)) { }
+
+  llvm::Constant *BuildName(QualType Ty, bool Hidden, 
+                            llvm::GlobalVariable::LinkageTypes Linkage) {
+    llvm::SmallString<256> OutName;
+    CGM.getMangleContext().mangleCXXRTTIName(Ty, OutName);
+    llvm::StringRef Name = OutName.str();
+
+    llvm::GlobalVariable *OGV = CGM.getModule().getNamedGlobal(Name);
+    if (OGV && !OGV->isDeclaration())
+      return llvm::ConstantExpr::getBitCast(OGV, Int8PtrTy);
+
+    llvm::Constant *C = llvm::ConstantArray::get(VMContext, Name.substr(4));
+
+    llvm::GlobalVariable *GV = 
+      new llvm::GlobalVariable(CGM.getModule(), C->getType(), true, Linkage,
+                               C, Name);
+    if (OGV) {
+      GV->takeName(OGV);
+      llvm::Constant *NewPtr = llvm::ConstantExpr::getBitCast(GV,
+                                                              OGV->getType());
+      OGV->replaceAllUsesWith(NewPtr);
+      OGV->eraseFromParent();
+    }
+    if (Hidden)
+      GV->setVisibility(llvm::GlobalVariable::HiddenVisibility);
+    return llvm::ConstantExpr::getBitCast(GV, Int8PtrTy);
+  }
+
+  // FIXME: unify with DecideExtern
+  bool DecideHidden(QualType Ty) {
+    // For this type, see if all components are never hidden.
+    if (const MemberPointerType *MPT = Ty->getAs<MemberPointerType>())
+      return (DecideHidden(MPT->getPointeeType())
+              && DecideHidden(QualType(MPT->getClass(), 0)));
+    if (const PointerType *PT = Ty->getAs<PointerType>())
+      return DecideHidden(PT->getPointeeType());
+    if (const FunctionType *FT = Ty->getAs<FunctionType>()) {
+      if (DecideHidden(FT->getResultType()) == false)
+        return false;
+      if (const FunctionProtoType *FPT = Ty->getAs<FunctionProtoType>()) {
+        for (unsigned i = 0; i <FPT->getNumArgs(); ++i)
+          if (DecideHidden(FPT->getArgType(i)) == false)
+            return false;
+        for (unsigned i = 0; i <FPT->getNumExceptions(); ++i)
+          if (DecideHidden(FPT->getExceptionType(i)) == false)
+            return false;
+        return true;
+      }
+    }
+    if (const RecordType *RT = Ty->getAs<RecordType>())
+      if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()))
+        return CGM.getDeclVisibilityMode(RD) == LangOptions::Hidden;
+    return false;
+  }
+  
+  // Pointer type info flags.
+  enum {
+    /// PTI_Const - Type has const qualifier.
+    PTI_Const = 0x1,
+    
+    /// PTI_Volatile - Type has volatile qualifier.
+    PTI_Volatile = 0x2,
+    
+    /// PTI_Restrict - Type has restrict qualifier.
+    PTI_Restrict = 0x4,
+    
+    /// PTI_Incomplete - Type is incomplete.
+    PTI_Incomplete = 0x8,
+    
+    /// PTI_ContainingClassIncomplete - Containing class is incomplete.
+    /// (in pointer to member).
+    PTI_ContainingClassIncomplete = 0x10
+  };
+  
+  // VMI type info flags.
+  enum {
+    /// VMI_NonDiamondRepeat - Class has non-diamond repeated inheritance.
+    VMI_NonDiamondRepeat = 0x1,
+    
+    /// VMI_DiamondShaped - Class is diamond shaped.
+    VMI_DiamondShaped = 0x2
+  };
+  
+  // Base class type info flags.
+  enum {
+    /// BCTI_Virtual - Base class is virtual.
+    BCTI_Virtual = 0x1,
+    
+    /// BCTI_Public - Base class is public.
+    BCTI_Public = 0x2
+  };
+  
+  /// BuildTypeInfo - Build the RTTI type info struct for the given type.
+  ///
+  /// \param Force - true to force the creation of this RTTI value
+  /// \param ForEH - true if this is for exception handling
+  llvm::Constant *BuildTypeInfo(QualType Ty, bool Force = false);
+};
+}
+
+llvm::Constant *RTTIBuilder::GetAddrOfExternalRTTIDescriptor(QualType Ty) {
+  // Mangle the RTTI name.
+  llvm::SmallString<256> OutName;
+  CGM.getMangleContext().mangleCXXRTTI(Ty, OutName);
+  llvm::StringRef Name = OutName.str();
+
+  // Look for an existing global.
+  llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(Name);
+  
+  if (!GV) {
+    // Create a new global variable.
+    GV = new llvm::GlobalVariable(CGM.getModule(), Int8PtrTy, /*Constant=*/true,
+                                  llvm::GlobalValue::ExternalLinkage, 0, Name);
+  }
+  
+  return llvm::ConstantExpr::getBitCast(GV, Int8PtrTy);
+}
+
+/// TypeInfoIsInStandardLibrary - Given a builtin type, returns whether the type
+/// info for that type is defined in the standard library.
+static bool TypeInfoIsInStandardLibrary(const BuiltinType *Ty) {
+  // Itanium C++ ABI 2.9.2:
+  //   Basic type information (e.g. for "int", "bool", etc.) will be kept in
+  //   the run-time support library. Specifically, the run-time support
+  //   library should contain type_info objects for the types X, X* and 
+  //   X const*, for every X in: void, bool, wchar_t, char, unsigned char, 
+  //   signed char, short, unsigned short, int, unsigned int, long, 
+  //   unsigned long, long long, unsigned long long, float, double, long double, 
+  //   char16_t, char32_t, and the IEEE 754r decimal and half-precision 
+  //   floating point types.
+  switch (Ty->getKind()) {
+    case BuiltinType::Void:
+    case BuiltinType::Bool:
+    case BuiltinType::WChar:
+    case BuiltinType::Char_U:
+    case BuiltinType::Char_S:
+    case BuiltinType::UChar:
+    case BuiltinType::SChar:
+    case BuiltinType::Short:
+    case BuiltinType::UShort:
+    case BuiltinType::Int:
+    case BuiltinType::UInt:
+    case BuiltinType::Long:
+    case BuiltinType::ULong:
+    case BuiltinType::LongLong:
+    case BuiltinType::ULongLong:
+    case BuiltinType::Float:
+    case BuiltinType::Double:
+    case BuiltinType::LongDouble:
+    case BuiltinType::Char16:
+    case BuiltinType::Char32:
+    case BuiltinType::Int128:
+    case BuiltinType::UInt128:
+      return true;
+      
+    case BuiltinType::Overload:
+    case BuiltinType::Dependent:
+    case BuiltinType::UndeducedAuto:
+      assert(false && "Should not see this type here!");
+      
+    case BuiltinType::NullPtr:
+      assert(false && "FIXME: nullptr_t is not handled!");
+
+    case BuiltinType::ObjCId:
+    case BuiltinType::ObjCClass:
+    case BuiltinType::ObjCSel:
+      assert(false && "FIXME: Objective-C types are unsupported!");
+  }
+  
+  // Silent gcc.
+  return false;
+}
+
+static bool TypeInfoIsInStandardLibrary(const PointerType *PointerTy) {
+  QualType PointeeTy = PointerTy->getPointeeType();
+  const BuiltinType *BuiltinTy = dyn_cast<BuiltinType>(PointeeTy);
+  if (!BuiltinTy)
+    return false;
+    
+  // Check the qualifiers.
+  Qualifiers Quals = PointeeTy.getQualifiers();
+  Quals.removeConst();
+    
+  if (!Quals.empty())
+    return false;
+    
+  return TypeInfoIsInStandardLibrary(BuiltinTy);
+}
+
+/// ShouldUseExternalRTTIDescriptor - Returns whether the type information for
+/// the given type exists somewhere else, and that we should not emit the type
+/// information in this translation unit.
+static bool ShouldUseExternalRTTIDescriptor(ASTContext &Context,
+                                            QualType Ty) {
+  // Type info for builtin types is defined in the standard library.
+  if (const BuiltinType *BuiltinTy = dyn_cast<BuiltinType>(Ty))
+    return TypeInfoIsInStandardLibrary(BuiltinTy);
+  
+  // Type info for some pointer types to builtin types is defined in the
+  // standard library.
+  if (const PointerType *PointerTy = dyn_cast<PointerType>(Ty))
+    return TypeInfoIsInStandardLibrary(PointerTy);
+
+  // If RTTI is disabled, don't consider key functions.
+  if (!Context.getLangOptions().RTTI) return false;
+
+  if (const RecordType *RecordTy = dyn_cast<RecordType>(Ty)) {
+    const CXXRecordDecl *RD = cast<CXXRecordDecl>(RecordTy->getDecl());
+    if (!RD->hasDefinition())
+      return false;
+
+    if (!RD->isDynamicClass())
+      return false;
+
+    // Get the key function.
+    const CXXMethodDecl *KeyFunction = RD->getASTContext().getKeyFunction(RD);
+    if (KeyFunction && !KeyFunction->getBody()) {
+      // The class has a key function, but it is not defined in this translation
+      // unit, so we should use the external descriptor for it.
+      return true;
+    }
+  }
+  
+  return false;
+}
+
+/// IsIncompleteClassType - Returns whether the given record type is incomplete.
+static bool IsIncompleteClassType(const RecordType *RecordTy) {
+  return !RecordTy->getDecl()->isDefinition();
+}  
+
+/// ContainsIncompleteClassType - Returns whether the given type contains an
+/// incomplete class type. This is true if
+///
+///   * The given type is an incomplete class type.
+///   * The given type is a pointer type whose pointee type contains an 
+///     incomplete class type.
+///   * The given type is a member pointer type whose class is an incomplete
+///     class type.
+///   * The given type is a member pointer type whoise pointee type contains an
+///     incomplete class type.
+/// is an indirect or direct pointer to an incomplete class type.
+static bool ContainsIncompleteClassType(QualType Ty) {
+  if (const RecordType *RecordTy = dyn_cast<RecordType>(Ty)) {
+    if (IsIncompleteClassType(RecordTy))
+      return true;
+  }
+  
+  if (const PointerType *PointerTy = dyn_cast<PointerType>(Ty))
+    return ContainsIncompleteClassType(PointerTy->getPointeeType());
+  
+  if (const MemberPointerType *MemberPointerTy = 
+      dyn_cast<MemberPointerType>(Ty)) {
+    // Check if the class type is incomplete.
+    const RecordType *ClassType = cast<RecordType>(MemberPointerTy->getClass());
+    if (IsIncompleteClassType(ClassType))
+      return true;
+    
+    return ContainsIncompleteClassType(MemberPointerTy->getPointeeType());
+  }
+  
+  return false;
+}
+
+/// getTypeInfoLinkage - Return the linkage that the type info and type info
+/// name constants should have for the given type.
+static llvm::GlobalVariable::LinkageTypes getTypeInfoLinkage(QualType Ty) {
+  // Itanium C++ ABI 2.9.5p7:
+  //   In addition, it and all of the intermediate abi::__pointer_type_info 
+  //   structs in the chain down to the abi::__class_type_info for the
+  //   incomplete class type must be prevented from resolving to the 
+  //   corresponding type_info structs for the complete class type, possibly
+  //   by making them local static objects. Finally, a dummy class RTTI is
+  //   generated for the incomplete type that will not resolve to the final 
+  //   complete class RTTI (because the latter need not exist), possibly by 
+  //   making it a local static object.
+  if (ContainsIncompleteClassType(Ty))
+    return llvm::GlobalValue::InternalLinkage;
+  
+  switch (Ty->getLinkage()) {
+  case NoLinkage:
+  case InternalLinkage:
+  case UniqueExternalLinkage:
+    return llvm::GlobalValue::InternalLinkage;
+
+  case ExternalLinkage:
+    if (const RecordType *Record = dyn_cast<RecordType>(Ty)) {
+      const CXXRecordDecl *RD = cast<CXXRecordDecl>(Record->getDecl());
+      if (RD->isDynamicClass())
+        return CodeGenModule::getVTableLinkage(RD);
+    }
+
+    return llvm::GlobalValue::WeakODRLinkage;
+  }
+
+  return llvm::GlobalValue::WeakODRLinkage;
+}
+
+// CanUseSingleInheritance - Return whether the given record decl has a "single, 
+// public, non-virtual base at offset zero (i.e. the derived class is dynamic 
+// iff the base is)", according to Itanium C++ ABI, 2.95p6b.
+static bool CanUseSingleInheritance(const CXXRecordDecl *RD) {
+  // Check the number of bases.
+  if (RD->getNumBases() != 1)
+    return false;
+  
+  // Get the base.
+  CXXRecordDecl::base_class_const_iterator Base = RD->bases_begin();
+  
+  // Check that the base is not virtual.
+  if (Base->isVirtual())
+    return false;
+  
+  // Check that the base is public.
+  if (Base->getAccessSpecifier() != AS_public)
+    return false;
+  
+  // Check that the class is dynamic iff the base is.
+  const CXXRecordDecl *BaseDecl = 
+    cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
+  if (!BaseDecl->isEmpty() && 
+      BaseDecl->isDynamicClass() != RD->isDynamicClass())
+    return false;
+  
+  return true;
+}
+
+void RTTIBuilder::BuildVTablePointer(const Type *Ty) {
+  const char *VTableName;
+
+  switch (Ty->getTypeClass()) {
+  default: assert(0 && "Unhandled type!");
+
+  case Type::Builtin:
+  // GCC treats vector types as fundamental types.
+  case Type::Vector:
+  case Type::ExtVector:
+    // abi::__fundamental_type_info.
+    VTableName = "_ZTVN10__cxxabiv123__fundamental_type_infoE";
+    break;
+
+  case Type::ConstantArray:
+  case Type::IncompleteArray:
+    // abi::__array_type_info.
+    VTableName = "_ZTVN10__cxxabiv117__array_type_infoE";
+    break;
+
+  case Type::FunctionNoProto:
+  case Type::FunctionProto:
+    // abi::__function_type_info.
+    VTableName = "_ZTVN10__cxxabiv120__function_type_infoE";
+    break;
+
+  case Type::Enum:
+    // abi::__enum_type_info.
+    VTableName = "_ZTVN10__cxxabiv116__enum_type_infoE";
+    break;
+      
+  case Type::Record: {
+    const CXXRecordDecl *RD = 
+      cast<CXXRecordDecl>(cast<RecordType>(Ty)->getDecl());
+    
+    if (!RD->hasDefinition() || !RD->getNumBases()) {
+      // abi::__class_type_info.
+      VTableName = "_ZTVN10__cxxabiv117__class_type_infoE";
+    } else if (CanUseSingleInheritance(RD)) {
+      // abi::__si_class_type_info.
+      VTableName = "_ZTVN10__cxxabiv120__si_class_type_infoE";
+    } else {
+      // abi::__vmi_class_type_info.
+      VTableName = "_ZTVN10__cxxabiv121__vmi_class_type_infoE";
+    }
+    
+    break;
+  }
+
+  case Type::Pointer:
+    // abi::__pointer_type_info.
+    VTableName = "_ZTVN10__cxxabiv119__pointer_type_infoE";
+    break;
+
+  case Type::MemberPointer:
+    // abi::__pointer_to_member_type_info.
+    VTableName = "_ZTVN10__cxxabiv129__pointer_to_member_type_infoE";
+    break;
+  }
+
+  llvm::Constant *VTable = 
+    CGM.getModule().getOrInsertGlobal(VTableName, Int8PtrTy);
+    
+  const llvm::Type *PtrDiffTy = 
+    CGM.getTypes().ConvertType(CGM.getContext().getPointerDiffType());
+
+  // The vtable address point is 2.
+  llvm::Constant *Two = llvm::ConstantInt::get(PtrDiffTy, 2);
+  VTable = llvm::ConstantExpr::getInBoundsGetElementPtr(VTable, &Two, 1);
+  VTable = llvm::ConstantExpr::getBitCast(VTable, Int8PtrTy);
+
+  Fields.push_back(VTable);
+}
+
+llvm::Constant *RTTIBuilder::BuildTypeInfo(QualType Ty,
+                                           bool Force) {
+  // We want to operate on the canonical type.
+  Ty = CGM.getContext().getCanonicalType(Ty);
+
+  // Check if we've already emitted an RTTI descriptor for this type.
+  llvm::SmallString<256> OutName;
+  CGM.getMangleContext().mangleCXXRTTI(Ty, OutName);
+  llvm::StringRef Name = OutName.str();
+  
+  llvm::GlobalVariable *OldGV = CGM.getModule().getNamedGlobal(Name);
+  if (OldGV && !OldGV->isDeclaration())
+    return llvm::ConstantExpr::getBitCast(OldGV, Int8PtrTy);
+  
+  // Check if there is already an external RTTI descriptor for this type.
+  if (!Force && ShouldUseExternalRTTIDescriptor(CGM.getContext(), Ty))
+    return GetAddrOfExternalRTTIDescriptor(Ty);
+
+  llvm::GlobalVariable::LinkageTypes Linkage = getTypeInfoLinkage(Ty);
+
+  // Add the vtable pointer.
+  BuildVTablePointer(cast<Type>(Ty));
+  
+  // And the name.
+  Fields.push_back(BuildName(Ty, DecideHidden(Ty), Linkage));
+  
+  switch (Ty->getTypeClass()) {
+  default: assert(false && "Unhandled type class!");
+
+  // GCC treats vector types as fundamental types.
+  case Type::Builtin:
+  case Type::Vector:
+  case Type::ExtVector:
+    // Itanium C++ ABI 2.9.5p4:
+    // abi::__fundamental_type_info adds no data members to std::type_info.
+    break;
+      
+  case Type::ConstantArray:
+  case Type::IncompleteArray:
+    // Itanium C++ ABI 2.9.5p5:
+    // abi::__array_type_info adds no data members to std::type_info.
+    break;
+
+  case Type::FunctionNoProto:
+  case Type::FunctionProto:
+    // Itanium C++ ABI 2.9.5p5:
+    // abi::__function_type_info adds no data members to std::type_info.
+    break;
+
+  case Type::Enum:
+    // Itanium C++ ABI 2.9.5p5:
+    // abi::__enum_type_info adds no data members to std::type_info.
+    break;
+
+  case Type::Record: {
+    const CXXRecordDecl *RD = 
+      cast<CXXRecordDecl>(cast<RecordType>(Ty)->getDecl());
+    if (!RD->hasDefinition() || !RD->getNumBases()) {
+      // We don't need to emit any fields.
+      break;
+    }
+    
+    if (CanUseSingleInheritance(RD))
+      BuildSIClassTypeInfo(RD);
+    else 
+      BuildVMIClassTypeInfo(RD);
+
+    break;
+  }
+      
+  case Type::Pointer:
+    BuildPointerTypeInfo(cast<PointerType>(Ty));
+    break;
+  
+  case Type::MemberPointer:
+    BuildPointerToMemberTypeInfo(cast<MemberPointerType>(Ty));
+    break;
+  }
+
+  llvm::Constant *Init = 
+    llvm::ConstantStruct::get(VMContext, &Fields[0], Fields.size(), 
+                              /*Packed=*/false);
+
+  llvm::GlobalVariable *GV = 
+    new llvm::GlobalVariable(CGM.getModule(), Init->getType(), 
+                             /*Constant=*/true, Linkage, Init, Name);
+  
+  // If there's already an old global variable, replace it with the new one.
+  if (OldGV) {
+    GV->takeName(OldGV);
+    llvm::Constant *NewPtr = 
+      llvm::ConstantExpr::getBitCast(GV, OldGV->getType());
+    OldGV->replaceAllUsesWith(NewPtr);
+    OldGV->eraseFromParent();
+  }
+    
+  return llvm::ConstantExpr::getBitCast(GV, Int8PtrTy);
+}
+
+/// ComputeQualifierFlags - Compute the pointer type info flags from the
+/// given qualifier.
+static unsigned ComputeQualifierFlags(Qualifiers Quals) {
+  unsigned Flags = 0;
+
+  if (Quals.hasConst())
+    Flags |= RTTIBuilder::PTI_Const;
+  if (Quals.hasVolatile())
+    Flags |= RTTIBuilder::PTI_Volatile;
+  if (Quals.hasRestrict())
+    Flags |= RTTIBuilder::PTI_Restrict;
+
+  return Flags;
+}
+
+/// BuildSIClassTypeInfo - Build an abi::__si_class_type_info, used for single
+/// inheritance, according to the Itanium C++ ABI, 2.95p6b.
+void RTTIBuilder::BuildSIClassTypeInfo(const CXXRecordDecl *RD) {
+  // Itanium C++ ABI 2.9.5p6b:
+  // It adds to abi::__class_type_info a single member pointing to the 
+  // type_info structure for the base type,
+  llvm::Constant *BaseTypeInfo = 
+    RTTIBuilder(CGM).BuildTypeInfo(RD->bases_begin()->getType());
+  Fields.push_back(BaseTypeInfo);
+}
+
+/// SeenBases - Contains virtual and non-virtual bases seen when traversing
+/// a class hierarchy.
+struct SeenBases {
+  llvm::SmallPtrSet<const CXXRecordDecl *, 16> NonVirtualBases;
+  llvm::SmallPtrSet<const CXXRecordDecl *, 16> VirtualBases;
+};
+
+/// ComputeVMIClassTypeInfoFlags - Compute the value of the flags member in
+/// abi::__vmi_class_type_info.
+///
+static unsigned ComputeVMIClassTypeInfoFlags(const CXXBaseSpecifier *Base, 
+                                             SeenBases &Bases) {
+  
+  unsigned Flags = 0;
+  
+  const CXXRecordDecl *BaseDecl = 
+    cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
+  
+  if (Base->isVirtual()) {
+    if (Bases.VirtualBases.count(BaseDecl)) {
+      // If this virtual base has been seen before, then the class is diamond
+      // shaped.
+      Flags |= RTTIBuilder::VMI_DiamondShaped;
+    } else {
+      if (Bases.NonVirtualBases.count(BaseDecl))
+        Flags |= RTTIBuilder::VMI_NonDiamondRepeat;
+
+      // Mark the virtual base as seen.
+      Bases.VirtualBases.insert(BaseDecl);
+    }
+  } else {
+    if (Bases.NonVirtualBases.count(BaseDecl)) {
+      // If this non-virtual base has been seen before, then the class has non-
+      // diamond shaped repeated inheritance.
+      Flags |= RTTIBuilder::VMI_NonDiamondRepeat;
+    } else {
+      if (Bases.VirtualBases.count(BaseDecl))
+        Flags |= RTTIBuilder::VMI_NonDiamondRepeat;
+        
+      // Mark the non-virtual base as seen.
+      Bases.NonVirtualBases.insert(BaseDecl);
+    }
+  }
+
+  // Walk all bases.
+  for (CXXRecordDecl::base_class_const_iterator I = BaseDecl->bases_begin(),
+       E = BaseDecl->bases_end(); I != E; ++I) 
+    Flags |= ComputeVMIClassTypeInfoFlags(I, Bases);
+  
+  return Flags;
+}
+
+static unsigned ComputeVMIClassTypeInfoFlags(const CXXRecordDecl *RD) {
+  unsigned Flags = 0;
+  SeenBases Bases;
+  
+  // Walk all bases.
+  for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
+       E = RD->bases_end(); I != E; ++I) 
+    Flags |= ComputeVMIClassTypeInfoFlags(I, Bases);
+  
+  return Flags;
+}
+
+/// BuildVMIClassTypeInfo - Build an abi::__vmi_class_type_info, used for
+/// classes with bases that do not satisfy the abi::__si_class_type_info 
+/// constraints, according ti the Itanium C++ ABI, 2.9.5p5c.
+void RTTIBuilder::BuildVMIClassTypeInfo(const CXXRecordDecl *RD) {
+  const llvm::Type *UnsignedIntLTy = 
+    CGM.getTypes().ConvertType(CGM.getContext().UnsignedIntTy);
+  
+  // Itanium C++ ABI 2.9.5p6c:
+  //   __flags is a word with flags describing details about the class 
+  //   structure, which may be referenced by using the __flags_masks 
+  //   enumeration. These flags refer to both direct and indirect bases. 
+  unsigned Flags = ComputeVMIClassTypeInfoFlags(RD);
+  Fields.push_back(llvm::ConstantInt::get(UnsignedIntLTy, Flags));
+
+  // Itanium C++ ABI 2.9.5p6c:
+  //   __base_count is a word with the number of direct proper base class 
+  //   descriptions that follow.
+  Fields.push_back(llvm::ConstantInt::get(UnsignedIntLTy, RD->getNumBases()));
+  
+  if (!RD->getNumBases())
+    return;
+  
+  const llvm::Type *LongLTy = 
+    CGM.getTypes().ConvertType(CGM.getContext().LongTy);
+
+  // Now add the base class descriptions.
+  
+  // Itanium C++ ABI 2.9.5p6c:
+  //   __base_info[] is an array of base class descriptions -- one for every 
+  //   direct proper base. Each description is of the type:
+  //
+  //   struct abi::__base_class_type_info {
+	//   public:
+  //     const __class_type_info *__base_type;
+  //     long __offset_flags;
+  //
+  //     enum __offset_flags_masks {
+  //       __virtual_mask = 0x1,
+  //       __public_mask = 0x2,
+  //       __offset_shift = 8
+  //     };
+  //   };
+  for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
+       E = RD->bases_end(); I != E; ++I) {
+    const CXXBaseSpecifier *Base = I;
+
+    // The __base_type member points to the RTTI for the base type.
+    Fields.push_back(RTTIBuilder(CGM).BuildTypeInfo(Base->getType()));
+
+    const CXXRecordDecl *BaseDecl = 
+      cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
+
+    int64_t OffsetFlags = 0;
+    
+    // All but the lower 8 bits of __offset_flags are a signed offset. 
+    // For a non-virtual base, this is the offset in the object of the base
+    // subobject. For a virtual base, this is the offset in the virtual table of
+    // the virtual base offset for the virtual base referenced (negative).
+    if (Base->isVirtual())
+      OffsetFlags = CGM.getVTables().getVirtualBaseOffsetOffset(RD, BaseDecl);
+    else {
+      const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
+      OffsetFlags = Layout.getBaseClassOffset(BaseDecl) / 8;
+    };
+    
+    OffsetFlags <<= 8;
+    
+    // The low-order byte of __offset_flags contains flags, as given by the 
+    // masks from the enumeration __offset_flags_masks.
+    if (Base->isVirtual())
+      OffsetFlags |= BCTI_Virtual;
+    if (Base->getAccessSpecifier() == AS_public)
+      OffsetFlags |= BCTI_Public;
+
+    Fields.push_back(llvm::ConstantInt::get(LongLTy, OffsetFlags));
+  }
+}
+
+/// BuildPointerTypeInfo - Build an abi::__pointer_type_info struct,
+/// used for pointer types.
+void RTTIBuilder::BuildPointerTypeInfo(const PointerType *Ty) {
+  QualType PointeeTy = Ty->getPointeeType();
+  
+  // Itanium C++ ABI 2.9.5p7:
+  //   __flags is a flag word describing the cv-qualification and other 
+  //   attributes of the type pointed to
+  unsigned Flags = ComputeQualifierFlags(PointeeTy.getQualifiers());
+
+  // Itanium C++ ABI 2.9.5p7:
+  //   When the abi::__pbase_type_info is for a direct or indirect pointer to an
+  //   incomplete class type, the incomplete target type flag is set. 
+  if (ContainsIncompleteClassType(PointeeTy))
+    Flags |= PTI_Incomplete;
+
+  const llvm::Type *UnsignedIntLTy = 
+    CGM.getTypes().ConvertType(CGM.getContext().UnsignedIntTy);
+  Fields.push_back(llvm::ConstantInt::get(UnsignedIntLTy, Flags));
+  
+  // Itanium C++ ABI 2.9.5p7:
+  //  __pointee is a pointer to the std::type_info derivation for the 
+  //  unqualified type being pointed to.
+  llvm::Constant *PointeeTypeInfo = 
+    RTTIBuilder(CGM).BuildTypeInfo(PointeeTy.getUnqualifiedType());
+  Fields.push_back(PointeeTypeInfo);
+}
+
+/// BuildPointerToMemberTypeInfo - Build an abi::__pointer_to_member_type_info 
+/// struct, used for member pointer types.
+void RTTIBuilder::BuildPointerToMemberTypeInfo(const MemberPointerType *Ty) {
+  QualType PointeeTy = Ty->getPointeeType();
+  
+  // Itanium C++ ABI 2.9.5p7:
+  //   __flags is a flag word describing the cv-qualification and other 
+  //   attributes of the type pointed to.
+  unsigned Flags = ComputeQualifierFlags(PointeeTy.getQualifiers());
+
+  const RecordType *ClassType = cast<RecordType>(Ty->getClass());
+
+  // Itanium C++ ABI 2.9.5p7:
+  //   When the abi::__pbase_type_info is for a direct or indirect pointer to an
+  //   incomplete class type, the incomplete target type flag is set. 
+  if (ContainsIncompleteClassType(PointeeTy))
+    Flags |= PTI_Incomplete;
+
+  if (IsIncompleteClassType(ClassType))
+    Flags |= PTI_ContainingClassIncomplete;
+  
+  const llvm::Type *UnsignedIntLTy = 
+    CGM.getTypes().ConvertType(CGM.getContext().UnsignedIntTy);
+  Fields.push_back(llvm::ConstantInt::get(UnsignedIntLTy, Flags));
+  
+  // Itanium C++ ABI 2.9.5p7:
+  //   __pointee is a pointer to the std::type_info derivation for the 
+  //   unqualified type being pointed to.
+  llvm::Constant *PointeeTypeInfo = 
+    RTTIBuilder(CGM).BuildTypeInfo(PointeeTy.getUnqualifiedType());
+  Fields.push_back(PointeeTypeInfo);
+
+  // Itanium C++ ABI 2.9.5p9:
+  //   __context is a pointer to an abi::__class_type_info corresponding to the
+  //   class type containing the member pointed to 
+  //   (e.g., the "A" in "int A::*").
+  Fields.push_back(RTTIBuilder(CGM).BuildTypeInfo(QualType(ClassType, 0)));
+}
+
+llvm::Constant *CodeGenModule::GetAddrOfRTTIDescriptor(QualType Ty,
+                                                       bool ForEH) {
+  // Return a bogus pointer if RTTI is disabled, unless it's for EH.
+  // FIXME: should we even be calling this method if RTTI is disabled
+  // and it's not for EH?
+  if (!ForEH && !getContext().getLangOptions().RTTI) {
+    const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(VMContext);
+    return llvm::Constant::getNullValue(Int8PtrTy);
+  }
+
+  return RTTIBuilder(*this).BuildTypeInfo(Ty);
+}
+
+void CodeGenModule::EmitFundamentalRTTIDescriptor(QualType Type) {
+  QualType PointerType = Context.getPointerType(Type);
+  QualType PointerTypeConst = Context.getPointerType(Type.withConst());
+  RTTIBuilder(*this).BuildTypeInfo(Type, true);
+  RTTIBuilder(*this).BuildTypeInfo(PointerType, true);
+  RTTIBuilder(*this).BuildTypeInfo(PointerTypeConst, true);
+}
+
+void CodeGenModule::EmitFundamentalRTTIDescriptors() {
+  QualType FundamentalTypes[] = { Context.VoidTy, Context.Char32Ty,
+                                  Context.Char16Ty, Context.UnsignedLongLongTy,
+                                  Context.LongLongTy, Context.WCharTy,
+                                  Context.UnsignedShortTy, Context.ShortTy,
+                                  Context.UnsignedLongTy, Context.LongTy,
+                                  Context.UnsignedIntTy, Context.IntTy,
+                                  Context.UnsignedCharTy, Context.FloatTy,
+                                  Context.LongDoubleTy, Context.DoubleTy,
+                                  Context.CharTy, Context.BoolTy,
+                                  Context.SignedCharTy };
+  for (unsigned i = 0; i < sizeof(FundamentalTypes)/sizeof(QualType); ++i)
+    EmitFundamentalRTTIDescriptor(FundamentalTypes[i]);
+}