diff --git a/Driver/ASTConsumers.cpp b/Driver/ASTConsumers.cpp
index 790baf5..332f589 100644
--- a/Driver/ASTConsumers.cpp
+++ b/Driver/ASTConsumers.cpp
@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "ASTConsumers.h"
+#include "TranslationUnit.h"
 #include "clang/AST/AST.h"
 #include "clang/AST/ASTConsumer.h"
 #include "clang/AST/CFG.h"
@@ -604,3 +605,40 @@
   return new LLVMEmitter(Diags, Features);
 }
 
+//===----------------------------------------------------------------------===//
+// AST Serializer
+
+namespace {
+  class ASTSerializer : public ASTConsumer {
+    Diagnostic &Diags;
+    TranslationUnit TU;
+    const llvm::sys::Path FName;
+  public:
+    ASTSerializer(const llvm::sys::Path& F, Diagnostic &diags,
+                  const LangOptions &LO)
+    : Diags(diags), TU(LO), FName(F) {}
+
+    
+    virtual void Initialize(ASTContext &Context, unsigned MainFileID) {
+      TU.setContext(&Context);
+    }
+    
+    virtual void HandleTopLevelDecl(Decl *D) {
+      // If an error occurred, stop code generation, but continue parsing and
+      // semantic analysis (to ensure all warnings and errors are emitted).
+      if (Diags.hasErrorOccurred())
+        return;
+      
+      TU.AddTopLevelDecl(D);
+    }
+    
+    ~ASTSerializer() { TU.EmitBitcodeFile(FName); }
+  }; 
+} // end anonymous namespace
+
+
+ASTConsumer *clang::CreateASTSerializer(const llvm::sys::Path& FName,
+                                        Diagnostic &Diags,
+                                        const LangOptions &Features) {
+  return new ASTSerializer(FName, Diags, Features);
+}
diff --git a/Driver/ASTConsumers.h b/Driver/ASTConsumers.h
index ab2f0ee..027370f 100644
--- a/Driver/ASTConsumers.h
+++ b/Driver/ASTConsumers.h
@@ -16,6 +16,8 @@
 
 #include <iosfwd>
 
+namespace llvm { namespace sys { class Path; }}
+
 namespace clang {
 
 class ASTConsumer;
@@ -34,6 +36,9 @@
 ASTConsumer *CreateCodeRewriterTest(Diagnostic &Diags);
 ASTConsumer *CreateSerializationTest(Diagnostic &Diags, FileManager& FMgr, 
                                      const LangOptions &LOpts);
+  
+ASTConsumer *CreateASTSerializer(const llvm::sys::Path& FName,
+                                 Diagnostic &Diags, const LangOptions &LOpts);
 
 } // end clang namespace
 
diff --git a/Driver/TranslationUnit.cpp b/Driver/TranslationUnit.cpp
index 62a27f5..398afb0 100644
--- a/Driver/TranslationUnit.cpp
+++ b/Driver/TranslationUnit.cpp
@@ -33,7 +33,7 @@
 
 using namespace clang;
 
-bool TranslationUnit::EmitBitcodeFile(llvm::sys::Path& Filename) const {  
+bool TranslationUnit::EmitBitcodeFile(const llvm::sys::Path& Filename) const {  
 
   // Reserve 256K for bitstream buffer.
   std::vector<unsigned char> Buffer;
@@ -122,8 +122,9 @@
   Sezr.ExitBlock();  // exit "ASTContextBlock"
 }
 
-TranslationUnit* TranslationUnit::ReadBitcodeFile(llvm::sys::Path& Filename,
-                                                  FileManager& FMgr) {
+TranslationUnit*
+TranslationUnit::ReadBitcodeFile(const llvm::sys::Path& Filename,
+                                 FileManager& FMgr) {
   
   // Create the memory buffer that contains the contents of the file.  
   llvm::scoped_ptr<llvm::MemoryBuffer> 
diff --git a/Driver/TranslationUnit.h b/Driver/TranslationUnit.h
index f0c9366..b22ec46 100644
--- a/Driver/TranslationUnit.h
+++ b/Driver/TranslationUnit.h
@@ -47,7 +47,7 @@
   const LangOptions& getLangOpts() const { return LangOpts; }
   
   /// EmitBitcodeFile - Emit the translation unit to a bitcode file.
-  bool EmitBitcodeFile(llvm::sys::Path& Filename) const;
+  bool EmitBitcodeFile(const llvm::sys::Path& Filename) const;
   
   /// Emit - Emit the translation unit to an arbitray bitcode stream.
   void Emit(llvm::Serializer& S) const;
@@ -56,7 +56,7 @@
   static TranslationUnit* Create(llvm::Deserializer& D, FileManager& FMgr);
   
   /// ReadBitcodeFile - Reconsitute a translation unit from a bitcode file.
-  static TranslationUnit* ReadBitcodeFile(llvm::sys::Path& Filename,
+  static TranslationUnit* ReadBitcodeFile(const llvm::sys::Path& Filename,
                                           FileManager& FMgr); 
   
   // Accessors
diff --git a/Driver/clang.cpp b/Driver/clang.cpp
index 76cad92..8c08d7c 100644
--- a/Driver/clang.cpp
+++ b/Driver/clang.cpp
@@ -53,6 +53,7 @@
 enum ProgActions {
   RewriteTest,                  // Rewriter testing stuff.
   EmitLLVM,                     // Emit a .ll file.
+  SerializeAST,                 // Emit a .ast file.
   ASTPrint,                     // Parse ASTs and print them.
   ASTDump,                      // Parse ASTs and dump them.
   ASTView,                      // Parse ASTs and view them in Graphviz.
@@ -107,6 +108,8 @@
                         "Run prototype serializtion code."),
              clEnumValN(EmitLLVM, "emit-llvm",
                         "Build ASTs then convert to LLVM, emit .ll file"),
+             clEnumValN(SerializeAST, "serialize-ast",
+                        "Build ASTs and emit .ast file"),
              clEnumValN(RewriteTest, "rewrite-test",
                         "Playground for the code rewriter"),
              clEnumValEnd));
@@ -816,7 +819,8 @@
 /// CreateASTConsumer - Create the ASTConsumer for the corresponding program
 ///  action.  These consumers can operate on both ASTs that are freshly
 ///  parsed from source files as well as those deserialized from Bitcode.
-static ASTConsumer* CreateASTConsumer(Diagnostic& Diag, FileManager& FileMgr, 
+static ASTConsumer* CreateASTConsumer(const std::string& InFile,
+                                      Diagnostic& Diag, FileManager& FileMgr, 
                                       const LangOptions& LangOpts) {
   switch (ProgAction) {
     default:
@@ -850,6 +854,21 @@
     case EmitLLVM:
       return CreateLLVMEmitter(Diag, LangOpts);
       
+    case SerializeAST: {
+      // FIXME: Allow user to tailor where the file is written.
+      llvm::sys::Path FName = llvm::sys::Path::GetTemporaryDirectory(NULL);
+      FName.appendComponent((InFile + ".ast").c_str());
+      
+      if (FName.makeUnique(true,NULL)) {
+        fprintf (stderr, "error: cannot create serialized file: '%s'\n",
+                 FName.c_str());
+        
+        return NULL;
+      }
+      
+      return CreateASTSerializer(FName, Diag, LangOpts);
+    }
+      
     case RewriteTest:
       return CreateCodeRewriterTest(Diag);
   }
@@ -869,7 +888,8 @@
   
   switch (ProgAction) {
   default:
-    Consumer = CreateASTConsumer(PP.getDiagnostics(), HeaderInfo.getFileMgr(),
+    Consumer = CreateASTConsumer(InFile, PP.getDiagnostics(),
+                                 HeaderInfo.getFileMgr(),
                                  PP.getLangOptions());
     
     if (!Consumer) {      
@@ -964,7 +984,8 @@
   }
   
   TranslationUnit* TU = TranslationUnit::ReadBitcodeFile(Filename,FileMgr);  
-  ASTConsumer* Consumer = CreateASTConsumer(Diag,FileMgr,TU->getLangOpts());
+  ASTConsumer* Consumer = CreateASTConsumer(InFile,Diag,
+                                            FileMgr,TU->getLangOpts());
   
   if (!Consumer) {      
     fprintf(stderr, "Unsupported program action with serialized ASTs!\n");