4 files changed, 32 insertions, 19 deletions
diff --git a/include/clang/Serialization/ASTBitCodes.h b/include/clang/Serialization/ASTBitCodes.h
index 5d9e86cb08..32ac64e47b 100644
--- a/include/clang/Serialization/ASTBitCodes.h
+++ b/include/clang/Serialization/ASTBitCodes.h
@@ -367,9 +367,10 @@ namespace clang {
       /// declarations.
       TU_UPDATE_LEXICAL = 28,
       
-      /// \brief Record code for the array describing the first/last local
-      /// redeclarations of each entity.
-      LOCAL_REDECLARATIONS = 29,
+      /// \brief Record code for the array describing the locations (in the
+      /// LOCAL_REDECLARATIONS record) of the redeclaration chains, indexed by
+      /// the first known ID.
+      LOCAL_REDECLARATIONS_MAP = 29,
 
       /// \brief Record code for declarations that Sema keeps references of.
       SEMA_DECL_REFS = 30,
@@ -455,7 +456,13 @@ namespace clang {
       IMPORTED_MODULES = 51,
       
       /// \brief Record code for the set of merged declarations in an AST file.
-      MERGED_DECLARATIONS = 52
+      MERGED_DECLARATIONS = 52,
+      
+      /// \brief Record code for the array of redeclaration chains.
+      ///
+      /// This array can only be interpreted properly using the local 
+      /// redeclarations map.
+      LOCAL_REDECLARATIONS = 53
     };
 
     /// \brief Record types used within a source manager block.
@@ -1194,8 +1201,7 @@ namespace clang {
     /// \brief Describes the redeclarations of a declaration.
     struct LocalRedeclarationsInfo {
       DeclID FirstID;      // The ID of the first declaration
-      DeclID FirstLocalID; // The ID of the first local declaration
-      DeclID LastLocalID;  // The ID of the last local declaration
+      unsigned Offset;     // Offset into the array of redeclaration chains.
       
       friend bool operator<(const LocalRedeclarationsInfo &X,
                             const LocalRedeclarationsInfo &Y) {
diff --git a/include/clang/Serialization/ASTReader.h b/include/clang/Serialization/ASTReader.h
index 4a704d0c35..e7bdf50ae1 100644
--- a/include/clang/Serialization/ASTReader.h
+++ b/include/clang/Serialization/ASTReader.h
@@ -660,10 +660,10 @@ private:
   /// Objective-C protocols.
   std::deque<Decl *> InterestingDecls;
 
-  /// \brief We delay loading of the previous declaration chain to avoid
-  /// deeply nested calls when there are many redeclarations.
-  std::deque<std::pair<Decl *, serialization::DeclID> > PendingPreviousDecls;
-
+  /// \brief The set of redeclarable declaraations that have been deserialized
+  /// since the last time the declaration chains were linked.
+  llvm::SmallPtrSet<Decl *, 16> RedeclsDeserialized;
+  
   /// \brief The list of redeclaration chains that still need to be 
   /// reconstructed.
   ///
diff --git a/include/clang/Serialization/ASTWriter.h b/include/clang/Serialization/ASTWriter.h
index f0af06f86e..c97c9f42c8 100644
--- a/include/clang/Serialization/ASTWriter.h
+++ b/include/clang/Serialization/ASTWriter.h
@@ -25,6 +25,7 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/SetVector.h"
 #include "llvm/Bitcode/BitstreamWriter.h"
 #include <map>
 #include <queue>
@@ -312,11 +313,12 @@ private:
   /// serialized again. In this case, it is registered here, so that the reader
   /// knows to read the updated version.
   SmallVector<ReplacedDeclInfo, 16> ReplacedDecls;
-                    
-  /// \brief The list of local redeclarations of entities that were
-  /// first declared non-locally.
-  SmallVector<serialization::LocalRedeclarationsInfo, 2> LocalRedeclarations;
-                  
+                 
+  /// \brief The set of declarations that may have redeclaration chains that
+  /// need to be serialized.
+  llvm::SetVector<Decl *, llvm::SmallVector<Decl *, 4>, 
+                  llvm::SmallPtrSet<Decl *, 4> > Redeclarations;
+                                      
   /// \brief Statements that we've encountered while serializing a
   /// declaration or type.
   SmallVector<Stmt *, 16> StmtsToEmit;
@@ -415,6 +417,7 @@ private:
   void WriteDeclContextVisibleUpdate(const DeclContext *DC);
   void WriteFPPragmaOptions(const FPOptions &Opts);
   void WriteOpenCLExtensions(Sema &SemaRef);
+  void WriteRedeclarations();
   void WriteMergedDecls();
                         
   unsigned DeclParmVarAbbrev;
diff --git a/include/clang/Serialization/Module.h b/include/clang/Serialization/Module.h
index cbac5cd148..ad2c98e695 100644
--- a/include/clang/Serialization/Module.h
+++ b/include/clang/Serialization/Module.h
@@ -295,12 +295,16 @@ public:
   /// \brief Array of file-level DeclIDs sorted by file.
   const serialization::DeclID *FileSortedDecls;
 
-  /// \brief Array of redeclaration information within this module file,
-  /// sorted by the first declaration ID.
-  const serialization::LocalRedeclarationsInfo *RedeclarationsInfo;
+  /// \brief Array of redeclaration chain location information within this 
+  /// module file, sorted by the first declaration ID.
+  const serialization::LocalRedeclarationsInfo *RedeclarationsMap;
 
   /// \brief The number of redeclaration info entries in RedeclarationsInfo.
-  unsigned LocalNumRedeclarationsInfos;
+  unsigned LocalNumRedeclarationsInMap;
+  
+  /// \brief The redeclaration chains for declarations local to this
+  /// module file.
+  SmallVector<uint64_t, 1> RedeclarationChains;
   
   // === Types ===