diff --git a/include/clang/Serialization/ASTBitCodes.h b/include/clang/Serialization/ASTBitCodes.h
index a01bf62..4e7b0fa 100644
--- a/include/clang/Serialization/ASTBitCodes.h
+++ b/include/clang/Serialization/ASTBitCodes.h
@@ -47,6 +47,12 @@
     /// should be increased.
     const unsigned VERSION_MINOR = 0;
 
+    /// \brief An ID number that refers to an identifier in an AST file.
+    /// 
+    /// The ID numbers of identifiers are consecutive (in order of discovery)
+    /// and start at 1. 0 is reserved for NULL.
+    typedef uint32_t IdentifierID;
+    
     /// \brief An ID number that refers to a declaration in an AST file.
     ///
     /// The ID numbers of declarations are consecutive (in order of
diff --git a/include/clang/Serialization/ASTReader.h b/include/clang/Serialization/ASTReader.h
index bd21150..319c231 100644
--- a/include/clang/Serialization/ASTReader.h
+++ b/include/clang/Serialization/ASTReader.h
@@ -1424,20 +1424,21 @@
   /// \brief Report a diagnostic.
   DiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID);
 
-  IdentifierInfo *DecodeIdentifierInfo(unsigned Idx);
+  IdentifierInfo *DecodeIdentifierInfo(serialization::IdentifierID ID);
 
-  IdentifierInfo *GetIdentifierInfo(const RecordData &Record, unsigned &Idx) {
-    return DecodeIdentifierInfo(Record[Idx++]);
+  IdentifierInfo *GetIdentifierInfo(Module &M, const RecordData &Record, 
+                                    unsigned &Idx) {
+    return DecodeIdentifierInfo(getGlobalIdentifierID(M, Record[Idx++]));
   }
 
-  virtual IdentifierInfo *GetIdentifier(unsigned ID) {
+  virtual IdentifierInfo *GetIdentifier(serialization::IdentifierID ID) {
     return DecodeIdentifierInfo(ID);
   }
 
-  unsigned getGlobalIdentifierID(Module &M, unsigned LocalID) {
-    // FIXME: Remap local -> global identifier IDs
-    return LocalID;
-  }
+  IdentifierInfo *getLocalIdentifier(Module &M, unsigned LocalID);
+  
+  serialization::IdentifierID getGlobalIdentifierID(Module &M, 
+                                                    unsigned LocalID);
                                  
   /// \brief Read the source location entry with index ID.
   virtual bool ReadSLocEntry(int ID);
diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index acd31c9..1c9c106 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -523,7 +523,7 @@
     SelectorTable &SelTable = Reader.getContext()->Selectors;
     unsigned N = ReadUnalignedLE16(d);
     IdentifierInfo *FirstII
-      = Reader.DecodeIdentifierInfo(ReadUnalignedLE32(d));
+      = Reader.getLocalIdentifier(F, ReadUnalignedLE32(d));
     if (N == 0)
       return SelTable.getNullarySelector(FirstII);
     else if (N == 1)
@@ -532,7 +532,7 @@
     SmallVector<IdentifierInfo *, 16> Args;
     Args.push_back(FirstII);
     for (unsigned I = 1; I != N; ++I)
-      Args.push_back(Reader.DecodeIdentifierInfo(ReadUnalignedLE32(d)));
+      Args.push_back(Reader.getLocalIdentifier(F, ReadUnalignedLE32(d)));
 
     return SelTable.getSelector(N, Args.data());
   }
@@ -877,7 +877,7 @@
     Key.Kind = (DeclarationName::NameKind)*d++;
     switch (Key.Kind) {
     case DeclarationName::Identifier:
-      Key.Data = (uint64_t)Reader.DecodeIdentifierInfo(ReadUnalignedLE32(d));
+      Key.Data = (uint64_t)Reader.getLocalIdentifier(F, ReadUnalignedLE32(d));
       break;
     case DeclarationName::ObjCZeroArgSelector:
     case DeclarationName::ObjCOneArgSelector:
@@ -894,7 +894,7 @@
       Key.Data = *d++; // OverloadedOperatorKind
       break;
     case DeclarationName::CXXLiteralOperatorName:
-      Key.Data = (uint64_t)Reader.DecodeIdentifierInfo(ReadUnalignedLE32(d));
+      Key.Data = (uint64_t)Reader.getLocalIdentifier(F, ReadUnalignedLE32(d));
       break;
     case DeclarationName::CXXUsingDirective:
       break;
@@ -1462,7 +1462,7 @@
       if (Macro)
         return 0;
 
-      IdentifierInfo *II = DecodeIdentifierInfo(Record[0]);
+      IdentifierInfo *II = getLocalIdentifier(F, Record[0]);
       if (II == 0) {
         Error("macro must have a name in AST file");
         return 0;
@@ -1483,7 +1483,7 @@
         unsigned NumArgs = Record[5];
         NextIndex = 6 + NumArgs;
         for (unsigned i = 0; i != NumArgs; ++i)
-          MacroArgs.push_back(DecodeIdentifierInfo(Record[6+i]));
+          MacroArgs.push_back(getLocalIdentifier(F, Record[6+i]));
 
         // Install function-like macro info.
         MI->setIsFunctionLike();
@@ -1519,7 +1519,7 @@
       Tok.startToken();
       Tok.setLocation(ReadSourceLocation(F, Record[0]));
       Tok.setLength(Record[1]);
-      if (IdentifierInfo *II = DecodeIdentifierInfo(Record[2]))
+      if (IdentifierInfo *II = getLocalIdentifier(F, Record[2]))
         Tok.setIdentifierInfo(II);
       Tok.setKind((tok::TokenKind)Record[3]);
       Tok.setFlag((Token::TokenFlags)Record[4]);
@@ -1570,7 +1570,7 @@
       return PE;
     
     MacroExpansion *ME =
-      new (PPRec) MacroExpansion(DecodeIdentifierInfo(Record[3]),
+      new (PPRec) MacroExpansion(getLocalIdentifier(F, Record[3]),
                                  SourceRange(ReadSourceLocation(F, Record[1]),
                                              ReadSourceLocation(F, Record[2])),
                                  getMacroDefinition(Record[4]));
@@ -1589,7 +1589,7 @@
     
     // Decode the identifier info and then check again; if the macro is
     // still defined and associated with the identifier,
-    IdentifierInfo *II = DecodeIdentifierInfo(Record[4]);
+    IdentifierInfo *II = getLocalIdentifier(F, Record[4]);
     if (!MacroDefinitionsLoaded[Record[1] - 1]) {
       MacroDefinition *MD
         = new (PPRec) MacroDefinition(II,
@@ -1647,6 +1647,8 @@
   /// inode numbers, so that the search can cope with non-normalized path names
   /// and symlinks.
   class HeaderFileInfoTrait {
+    ASTReader &Reader;
+    Module &M;
     HeaderSearch *HS;
     const char *FrameworkStrings;
     const char *SearchPath;
@@ -1671,10 +1673,11 @@
     
     typedef HeaderFileInfo data_type;
     
-    HeaderFileInfoTrait(HeaderSearch *HS,
+    HeaderFileInfoTrait(ASTReader &Reader, Module &M, HeaderSearch *HS,
                         const char *FrameworkStrings,
                         const char *SearchPath = 0) 
-      : HS(HS), FrameworkStrings(FrameworkStrings), SearchPath(SearchPath) { }
+      : Reader(Reader), M(M), HS(HS), FrameworkStrings(FrameworkStrings), 
+        SearchPath(SearchPath) { }
     
     static unsigned ComputeHash(const char *path) {
       return llvm::HashString(llvm::sys::path::filename(path));
@@ -1721,7 +1724,7 @@
       HFI.Resolved = (Flags >> 1) & 0x01;
       HFI.IndexHeaderMapHeader = Flags & 0x01;
       HFI.NumIncludes = ReadUnalignedLE16(d);
-      HFI.ControllingMacroID = ReadUnalignedLE32(d);
+      HFI.ControllingMacroID = Reader.getGlobalDeclID(M, ReadUnalignedLE32(d));
       if (unsigned FrameworkOffset = ReadUnalignedLE32(d)) {
         // The framework offset is 1 greater than the actual offset, 
         // since 0 is used as an indicator for "no framework name".
@@ -1795,7 +1798,7 @@
 
       case PP_MACRO_OBJECT_LIKE:
       case PP_MACRO_FUNCTION_LIKE:
-        DecodeIdentifierInfo(Record[0]);
+        getLocalIdentifier(**I, Record[0]);
         break;
 
       case PP_TOKEN:
@@ -2492,7 +2495,8 @@
           = HeaderFileInfoLookupTable::Create(
                    (const unsigned char *)F.HeaderFileInfoTableData + Record[0],
                    (const unsigned char *)F.HeaderFileInfoTableData,
-                   HeaderFileInfoTrait(PP? &PP->getHeaderSearchInfo() : 0,
+                   HeaderFileInfoTrait(*this, F, 
+                                       PP? &PP->getHeaderSearchInfo() : 0,
                                        BlobStart + Record[2]));
         if (PP)
           PP->getHeaderSearchInfo().SetExternalSource(this);
@@ -3142,7 +3146,7 @@
   for (ModuleIterator I = ModuleMgr.begin(), E = ModuleMgr.end(); I != E; ++I) {
     Module &F = *(*I);
 
-    HeaderFileInfoTrait Trait(&PP->getHeaderSearchInfo(),
+    HeaderFileInfoTrait Trait(*this, F, &PP->getHeaderSearchInfo(),
                               F.HeaderFileFrameworkStrings,
                               FE->getName());
     
@@ -3565,7 +3569,7 @@
     unsigned Idx = 0;
     ElaboratedTypeKeyword Keyword = (ElaboratedTypeKeyword)Record[Idx++];
     NestedNameSpecifier *NNS = ReadNestedNameSpecifier(*Loc.F, Record, Idx);
-    const IdentifierInfo *Name = this->GetIdentifierInfo(Record, Idx);
+    const IdentifierInfo *Name = this->GetIdentifierInfo(*Loc.F, Record, Idx);
     QualType Canon = readType(*Loc.F, Record, Idx);
     if (!Canon.isNull())
       Canon = Context->getCanonicalType(Canon);
@@ -3576,7 +3580,7 @@
     unsigned Idx = 0;
     ElaboratedTypeKeyword Keyword = (ElaboratedTypeKeyword)Record[Idx++];
     NestedNameSpecifier *NNS = ReadNestedNameSpecifier(*Loc.F, Record, Idx);
-    const IdentifierInfo *Name = this->GetIdentifierInfo(Record, Idx);
+    const IdentifierInfo *Name = this->GetIdentifierInfo(*Loc.F, Record, Idx);
     unsigned NumArgs = Record[Idx++];
     SmallVector<TemplateArgument, 8> Args;
     Args.reserve(NumArgs);
@@ -4667,7 +4671,7 @@
   ReadMethodPool(Sel);
 }
 
-void ASTReader::SetIdentifierInfo(unsigned ID, IdentifierInfo *II) {
+void ASTReader::SetIdentifierInfo(IdentifierID ID, IdentifierInfo *II) {
   assert(ID && "Non-zero identifier ID required");
   assert(ID <= IdentifiersLoaded.size() && "identifier ID out of range");
   IdentifiersLoaded[ID - 1] = II;
@@ -4722,7 +4726,7 @@
   }
 }
 
-IdentifierInfo *ASTReader::DecodeIdentifierInfo(unsigned ID) {
+IdentifierInfo *ASTReader::DecodeIdentifierInfo(IdentifierID ID) {
   if (ID == 0)
     return 0;
 
@@ -4757,6 +4761,15 @@
   return IdentifiersLoaded[ID];
 }
 
+IdentifierInfo *ASTReader::getLocalIdentifier(Module &M, unsigned LocalID) {
+  return DecodeIdentifierInfo(getGlobalIdentifierID(M, LocalID));
+}
+
+IdentifierID ASTReader::getGlobalIdentifierID(Module &M, unsigned LocalID) {
+  // FIXME: Perform local-to-global remapping
+  return LocalID;
+}
+
 bool ASTReader::ReadSLocEntry(int ID) {
   return ReadSLocEntryRecord(ID) != Success;
 }
@@ -4807,7 +4820,7 @@
   DeclarationName::NameKind Kind = (DeclarationName::NameKind)Record[Idx++];
   switch (Kind) {
   case DeclarationName::Identifier:
-    return DeclarationName(GetIdentifierInfo(Record, Idx));
+    return DeclarationName(GetIdentifierInfo(F, Record, Idx));
 
   case DeclarationName::ObjCZeroArgSelector:
   case DeclarationName::ObjCOneArgSelector:
@@ -4832,7 +4845,7 @@
 
   case DeclarationName::CXXLiteralOperatorName:
     return Context->DeclarationNames.getCXXLiteralOperatorName(
-                                       GetIdentifierInfo(Record, Idx));
+                                       GetIdentifierInfo(F, Record, Idx));
 
   case DeclarationName::CXXUsingDirective:
     return DeclarationName::getUsingDirectiveName();
@@ -4924,7 +4937,8 @@
     NestedNameSpecifier *NNS = ReadNestedNameSpecifier(F, Record, Idx);
     if (Record[Idx++])  // isIdentifier
       return Context->getDependentTemplateName(NNS,
-                                               GetIdentifierInfo(Record, Idx));
+                                               GetIdentifierInfo(F, Record, 
+                                                                 Idx));
     return Context->getDependentTemplateName(NNS,
                                          (OverloadedOperatorKind)Record[Idx++]);
   }
@@ -5146,7 +5160,7 @@
       = (NestedNameSpecifier::SpecifierKind)Record[Idx++];
     switch (Kind) {
     case NestedNameSpecifier::Identifier: {
-      IdentifierInfo *II = GetIdentifierInfo(Record, Idx);
+      IdentifierInfo *II = GetIdentifierInfo(F, Record, Idx);
       NNS = NestedNameSpecifier::Create(*Context, Prev, II);
       break;
     }
@@ -5195,7 +5209,7 @@
       = (NestedNameSpecifier::SpecifierKind)Record[Idx++];
     switch (Kind) {
     case NestedNameSpecifier::Identifier: {
-      IdentifierInfo *II = GetIdentifierInfo(Record, Idx);      
+      IdentifierInfo *II = GetIdentifierInfo(F, Record, Idx);      
       SourceRange Range = ReadSourceRange(F, Record, Idx);
       Builder.Extend(*Context, II, Range.getBegin(), Range.getEnd());
       break;
diff --git a/lib/Serialization/ASTReaderDecl.cpp b/lib/Serialization/ASTReaderDecl.cpp
index 289b6c8..5b36743 100644
--- a/lib/Serialization/ASTReaderDecl.cpp
+++ b/lib/Serialization/ASTReaderDecl.cpp
@@ -650,7 +650,7 @@
 
 void ASTDeclReader::VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D) {
   VisitObjCImplDecl(D);
-  D->setIdentifier(Reader.GetIdentifierInfo(Record, Idx));
+  D->setIdentifier(Reader.GetIdentifierInfo(F, Record, Idx));
 }
 
 void ASTDeclReader::VisitObjCImplementationDecl(ObjCImplementationDecl *D) {
diff --git a/lib/Serialization/ASTReaderStmt.cpp b/lib/Serialization/ASTReaderStmt.cpp
index 7a3c589..5e8262b 100644
--- a/lib/Serialization/ASTReaderStmt.cpp
+++ b/lib/Serialization/ASTReaderStmt.cpp
@@ -287,7 +287,7 @@
   SmallVector<StringLiteral*, 16> Constraints;
   SmallVector<Stmt*, 16> Exprs;
   for (unsigned I = 0, N = NumOutputs + NumInputs; I != N; ++I) {
-    Names.push_back(Reader.GetIdentifierInfo(Record, Idx));
+    Names.push_back(Reader.GetIdentifierInfo(F, Record, Idx));
     Constraints.push_back(cast_or_null<StringLiteral>(Reader.ReadSubStmt()));
     Exprs.push_back(Reader.ReadSubStmt());
   }
@@ -440,7 +440,10 @@
       break;
 
     case Node::Identifier:
-      E->setComponent(I, Node(Start, Reader.GetIdentifier(Record[Idx++]), End));
+      E->setComponent(I, 
+                      Node(Start, 
+                           Reader.GetIdentifierInfo(F, Record, Idx),
+                           End));
       break;
         
     case Node::Base: {
@@ -593,7 +596,7 @@
 void ASTStmtReader::VisitExtVectorElementExpr(ExtVectorElementExpr *E) {
   VisitExpr(E);
   E->setBase(Reader.ReadSubExpr());
-  E->setAccessor(Reader.GetIdentifierInfo(Record, Idx));
+  E->setAccessor(Reader.GetIdentifierInfo(F, Record, Idx));
   E->setAccessorLoc(ReadSourceLocation(Record, Idx));
 }
 
@@ -650,7 +653,7 @@
     }
 
     case DESIG_FIELD_NAME: {
-      const IdentifierInfo *Name = Reader.GetIdentifierInfo(Record, Idx);
+      const IdentifierInfo *Name = Reader.GetIdentifierInfo(F, Record, Idx);
       SourceLocation DotLoc
         = ReadSourceLocation(Record, Idx);
       SourceLocation FieldLoc
@@ -1128,7 +1131,7 @@
   E->ColonColonLoc = ReadSourceLocation(Record, Idx);
   E->TildeLoc = ReadSourceLocation(Record, Idx);
   
-  IdentifierInfo *II = Reader.GetIdentifierInfo(Record, Idx);
+  IdentifierInfo *II = Reader.GetIdentifierInfo(F, Record, Idx);
   if (II)
     E->setDestroyedType(II, ReadSourceLocation(Record, Idx));
   else