diff --git a/lib/Frontend/CompilerInstance.cpp b/lib/Frontend/CompilerInstance.cpp
index 0ff70ed..fa5338d 100644
--- a/lib/Frontend/CompilerInstance.cpp
+++ b/lib/Frontend/CompilerInstance.cpp
@@ -255,6 +255,8 @@
   llvm::OwningPtr<ExternalASTSource> Source;
   Source.reset(createPCHExternalASTSource(Path, getHeaderSearchOpts().Sysroot,
                                           getPreprocessor(), getASTContext()));
+  // Remember the PCHReader, but in a non-owning way.
+  Reader = static_cast<PCHReader*>(Source.get());
   getASTContext().setExternalSource(Source);
 }
 
diff --git a/lib/Frontend/FrontendActions.cpp b/lib/Frontend/FrontendActions.cpp
index f0b86a9..400d353 100644
--- a/lib/Frontend/FrontendActions.cpp
+++ b/lib/Frontend/FrontendActions.cpp
@@ -81,9 +81,10 @@
     return 0;
 
   if (CI.getFrontendOpts().RelocatablePCH)
-    return CreatePCHGenerator(CI.getPreprocessor(), OS, Sysroot.c_str());
+    return CreatePCHGenerator(CI.getPreprocessor(), OS,
+                              CI.getPCHReader(), Sysroot.c_str());
 
-  return CreatePCHGenerator(CI.getPreprocessor(), OS);
+  return CreatePCHGenerator(CI.getPreprocessor(), OS, CI.getPCHReader());
 }
 
 ASTConsumer *InheritanceViewAction::CreateASTConsumer(CompilerInstance &CI,
diff --git a/lib/Frontend/GeneratePCH.cpp b/lib/Frontend/GeneratePCH.cpp
index 6251bac..9be103e 100644
--- a/lib/Frontend/GeneratePCH.cpp
+++ b/lib/Frontend/GeneratePCH.cpp
@@ -28,6 +28,7 @@
 namespace {
   class PCHGenerator : public SemaConsumer {
     const Preprocessor &PP;
+    const PCHReader *Chain;
     const char *isysroot;
     llvm::raw_ostream *Out;
     Sema *SemaPtr;
@@ -35,6 +36,7 @@
 
   public:
     explicit PCHGenerator(const Preprocessor &PP,
+                          const PCHReader *Chain,
                           const char *isysroot,
                           llvm::raw_ostream *Out);
     virtual void InitializeSema(Sema &S) { SemaPtr = &S; }
@@ -43,9 +45,11 @@
 }
 
 PCHGenerator::PCHGenerator(const Preprocessor &PP,
+                           const PCHReader *Chain,
                            const char *isysroot,
                            llvm::raw_ostream *OS)
-  : PP(PP), isysroot(isysroot), Out(OS), SemaPtr(0), StatCalls(0) {
+  : PP(PP), Chain(Chain), isysroot(isysroot), Out(OS), SemaPtr(0),
+    StatCalls(0) {
 
   // Install a stat() listener to keep track of all of the stat()
   // calls.
@@ -64,7 +68,7 @@
 
   // Emit the PCH file
   assert(SemaPtr && "No Sema?");
-  Writer.WritePCH(*SemaPtr, StatCalls, isysroot);
+  Writer.WritePCH(*SemaPtr, StatCalls, Chain, isysroot);
 
   // Write the generated bitstream to "Out".
   Out->write((char *)&Buffer.front(), Buffer.size());
@@ -75,6 +79,7 @@
 
 ASTConsumer *clang::CreatePCHGenerator(const Preprocessor &PP,
                                        llvm::raw_ostream *OS,
+                                       const PCHReader *Chain,
                                        const char *isysroot) {
-  return new PCHGenerator(PP, isysroot, OS);
+  return new PCHGenerator(PP, Chain, isysroot, OS);
 }
diff --git a/lib/Frontend/PCHWriter.cpp b/lib/Frontend/PCHWriter.cpp
index 8684a06..18ceef9 100644
--- a/lib/Frontend/PCHWriter.cpp
+++ b/lib/Frontend/PCHWriter.cpp
@@ -628,6 +628,7 @@
   RECORD(VERSION_CONTROL_BRANCH_REVISION);
   RECORD(UNUSED_STATIC_FUNCS);
   RECORD(MACRO_DEFINITION_OFFSETS);
+  RECORD(CHAINED_METADATA);
   
   // SourceManager Block.
   BLOCK(SOURCE_MANAGER_BLOCK);
@@ -2075,7 +2076,7 @@
     NumLexicalDeclContexts(0), NumVisibleDeclContexts(0) { }
 
 void PCHWriter::WritePCH(Sema &SemaRef, MemorizeStatCalls *StatCalls,
-                         const char *isysroot) {
+                         const PCHReader *Chain, const char *isysroot) {
   using namespace llvm;
 
   ASTContext &Context = SemaRef.Context;