3 files changed, 33 insertions, 9 deletions

diff --git a/include/clang/Serialization/ASTBitCodes.h b/include/clang/Serialization/ASTBitCodes.h
index 97b4cfc028..21fb8fa4ed 100644
--- a/include/clang/Serialization/ASTBitCodes.h
+++ b/include/clang/Serialization/ASTBitCodes.h
@@ -84,9 +84,15 @@ namespace clang {
 
       uint32_t getIndex() const { return Idx; }
       TypeID asTypeID(unsigned FastQuals) const {
+        if (Idx == uint32_t(-1))
+          return TypeID(-1);
+        
         return (Idx << Qualifiers::FastWidth) | FastQuals;
       }
       static TypeIdx fromTypeID(TypeID ID) {
+        if (ID == TypeID(-1))
+          return TypeIdx(-1);
+        
         return TypeIdx(ID >> Qualifiers::FastWidth);
       }
     };
diff --git a/include/clang/Serialization/ASTReader.h b/include/clang/Serialization/ASTReader.h
index e28179d335..e167985e30 100644
--- a/include/clang/Serialization/ASTReader.h
+++ b/include/clang/Serialization/ASTReader.h
@@ -380,9 +380,26 @@ public:
   /// type ID, or the representation of a Type*.
   const uint32_t *TypeOffsets;
   
-  /// \brief Base type ID for types local to this module.
-  serialization::TypeID BaseTypeID;
-  
+  /// \brief Base type ID for types local to this module as represented in 
+  /// the global type ID space.
+  serialization::TypeID GlobalBaseTypeIndex;
+  
+  /// \brief Remapping table for type IDs in this module.
+  ContinuousRangeMap<uint32_t, int, 2> TypeRemap;
+
+  /// \brief Base type ID for types local to this module as represented in
+  /// the module's type ID space.
+  serialization::TypeID LocalBaseTypeIndex;
+
+  /// \brief Remapping table that maps from a type as represented as a module
+  /// and local type index to the index used within the current module to
+  /// refer to that same type.
+  /// 
+  /// This mapping is effectively the reverse of the normal \c TypeRemap, and
+  /// is used specifically by ASTReader::GetTypeIdx() to help map between
+  /// global type IDs and a module's view of the same type ID as a hash value.
+  llvm::DenseMap<Module *, int> ReverseTypeRemap;
+
   // === Miscellaneous ===
   
   /// \brief Diagnostic IDs and their mappings that the user changed.
@@ -1233,6 +1250,10 @@ public:
   /// \brief Map a local type ID within a given AST file into a global type ID.
   serialization::TypeID getGlobalTypeID(Module &F, unsigned LocalID) const;
   
+  /// \brief Map a global type ID to an ID as it would be locally expressed
+  /// in the given model.
+  unsigned getLocalTypeID(Module &M, serialization::TypeID GlobalID);
+  
   /// \brief Read a type from the current position in the given record, which 
   /// was read from the given AST file.
   QualType readType(Module &F, const RecordData &Record, unsigned &Idx) {
diff --git a/include/clang/Serialization/ContinuousRangeMap.h b/include/clang/Serialization/ContinuousRangeMap.h
index 820086e820..42b8954b54 100644
--- a/include/clang/Serialization/ContinuousRangeMap.h
+++ b/include/clang/Serialization/ContinuousRangeMap.h
@@ -34,7 +34,7 @@ namespace clang {
 template <typename Int, typename V, unsigned InitialCapacity>
 class ContinuousRangeMap {
 public:
-  typedef std::pair<const Int, V> value_type;
+  typedef std::pair<Int, V> value_type;
   typedef value_type &reference;
   typedef const value_type &const_reference;
   typedef value_type *pointer;
@@ -94,7 +94,6 @@ public:
   /// from a set of values.
   class Builder {
     ContinuousRangeMap &Self;
-    SmallVector<std::pair<Int, V>, InitialCapacity> Elements;
     
     Builder(const Builder&); // DO NOT IMPLEMENT
     Builder &operator=(const Builder&); // DO NOT IMPLEMENT
@@ -103,13 +102,11 @@ public:
     explicit Builder(ContinuousRangeMap &Self) : Self(Self) { }
     
     ~Builder() {
-      std::sort(Elements.begin(), Elements.end(), Compare());
-      for (unsigned I = 0, N = Elements.size(); I != N; ++I)
-        Self.insert(Elements[I]);
+      std::sort(Self.Rep.begin(), Self.Rep.end(), Compare());
     }
     
     void insert(const value_type &Val) {
-      Elements.push_back(Val);
+      Self.Rep.push_back(Val);
     }
   };
   friend class Builder;