4 files changed, 54 insertions, 5 deletions
diff --git a/include/clang/Serialization/ASTBitCodes.h b/include/clang/Serialization/ASTBitCodes.h
index 22dc0b974c..3cfafd192e 100644
--- a/include/clang/Serialization/ASTBitCodes.h
+++ b/include/clang/Serialization/ASTBitCodes.h
@@ -127,7 +127,7 @@ namespace clang {
     /// \brief The number of predefined identifier IDs.
     const unsigned int NUM_PREDEF_IDENT_IDS = 1;
     
-    /// \brief An ID number that refers to an ObjC selctor in an AST file.
+    /// \brief An ID number that refers to an ObjC selector in an AST file.
     typedef uint32_t SelectorID;
 
     /// \brief The number of predefined selector IDs.
@@ -141,6 +141,12 @@ namespace clang {
     /// preprocessing record.
     typedef uint32_t PreprocessedEntityID;
 
+    /// \brief An ID number that refers to a submodule in a module file.
+    typedef uint32_t SubmoduleID;
+    
+    /// \brief The number of predefined submodule IDs.
+    const unsigned int NUM_PREDEF_SUBMODULE_IDS = 1;
+
     /// \brief Source range/offset of a preprocessed entity.
     struct PPEntityOffset {
       /// \brief Raw source location of beginning of range.
@@ -504,7 +510,9 @@ namespace clang {
       /// if any.
       SUBMODULE_UMBRELLA = 1,
       /// \brief Specifies a header that falls into this (sub)module.
-      SUBMODULE_HEADER = 2
+      SUBMODULE_HEADER = 2,
+      /// \brief Metadata for submodules as a whole.
+      SUBMODULE_METADATA = 3
     };
     
     /// \defgroup ASTAST AST file AST constants
diff --git a/include/clang/Serialization/ASTReader.h b/include/clang/Serialization/ASTReader.h
index c38ceb94c5..0e659acfa0 100644
--- a/include/clang/Serialization/ASTReader.h
+++ b/include/clang/Serialization/ASTReader.h
@@ -369,6 +369,20 @@ private:
   /// global identifier ID to produce a local ID.
   GlobalIdentifierMapType GlobalIdentifierMap;
 
+  /// \brief A vector containing submodules that have already been loaded.
+  ///
+  /// This vector is indexed by the Submodule ID (-1). NULL submodule entries
+  /// indicate that the particular submodule ID has not yet been loaded.
+  SmallVector<Module *, 2> SubmodulesLoaded;
+  
+  typedef ContinuousRangeMap<serialization::SubmoduleID, ModuleFile *, 4>
+    GlobalSubmoduleMapType;
+  
+  /// \brief Mapping from global submodule IDs to the module file in which the
+  /// submodule resides along with the offset that should be added to the
+  /// global submodule ID to produce a local ID.
+  GlobalSubmoduleMapType GlobalSubmoduleMap;
+
   /// \brief A vector containing selectors that have already been loaded.
   ///
   /// This vector is indexed by the Selector ID (-1). NULL selector
@@ -866,6 +880,11 @@ public:
     return static_cast<unsigned>(DeclsLoaded.size());
   }
 
+  /// \brief Returns the number of submodules known.
+  unsigned getTotalNumSubmodules() const {
+    return static_cast<unsigned>(SubmodulesLoaded.size());
+  }
+  
   /// \brief Returns the number of selectors found in the chain.
   unsigned getTotalNumSelectors() const {
     return static_cast<unsigned>(SelectorsLoaded.size());
@@ -1146,6 +1165,15 @@ public:
   /// \brief Read the source location entry with index ID.
   virtual bool ReadSLocEntry(int ID);
 
+  /// \brief Retrieve the global submodule ID given a module and its local ID
+  /// number.
+  serialization::SubmoduleID 
+  getGlobalSubmoduleID(ModuleFile &M, unsigned LocalID);
+  
+  /// \brief Retrieve the submodule that corresponds to a global submodule ID.
+  ///
+  Module *getSubmodule(serialization::SubmoduleID GlobalID);
+  
   /// \brief Retrieve a selector from the given module with its local ID
   /// number.
   Selector getLocalSelector(ModuleFile &M, unsigned LocalID);
diff --git a/include/clang/Serialization/ASTWriter.h b/include/clang/Serialization/ASTWriter.h
index b2ea48d5ae..ca29517d81 100644
--- a/include/clang/Serialization/ASTWriter.h
+++ b/include/clang/Serialization/ASTWriter.h
@@ -204,10 +204,16 @@ private:
   /// table.
   std::vector<uint32_t> IdentifierOffsets;
 
+  /// \brief The first ID number we can use for our own submodules.
+  serialization::SubmoduleID FirstSubmoduleID;
+  
+  /// \brief The submodule ID that will be assigned to the next new submodule.
+  serialization::SubmoduleID NextSubmoduleID;
+
   /// \brief The first ID number we can use for our own selectors.
   serialization::SelectorID FirstSelectorID;
 
-  /// \brief The selector ID that will be assigned to the next new identifier.
+  /// \brief The selector ID that will be assigned to the next new selector.
   serialization::SelectorID NextSelectorID;
 
   /// \brief Map that provides the ID numbers of each Selector.
diff --git a/include/clang/Serialization/Module.h b/include/clang/Serialization/Module.h
index 8874679eea..16d9779e04 100644
--- a/include/clang/Serialization/Module.h
+++ b/include/clang/Serialization/Module.h
@@ -201,8 +201,15 @@ public:
   /// search information.
   const char *HeaderFileFrameworkStrings;
 
-  // === Submodule information ===
-  llvm::SmallVector<Module *, 2> Submodules;
+  // === Submodule information ===  
+  /// \brief The number of submodules in this module.
+  unsigned LocalNumSubmodules;
+  
+  /// \brief Base submodule ID for submodules local to this module.
+  serialization::SubmoduleID BaseSubmoduleID;
+  
+  /// \brief Remapping table for submodule IDs in this module.
+  ContinuousRangeMap<uint32_t, int, 2> SubmoduleRemap;
   
   // === Selectors ===