3 files changed, 49 insertions, 7 deletions
diff --git a/lib/Frontend/ASTUnit.cpp b/lib/Frontend/ASTUnit.cpp
index 5e534b3d57..41f2442a11 100644
--- a/lib/Frontend/ASTUnit.cpp
+++ b/lib/Frontend/ASTUnit.cpp
@@ -92,7 +92,8 @@ const unsigned DefaultPreambleRebuildInterval = 5;
 static llvm::sys::cas_flag ActiveASTUnitObjects;
 
 ASTUnit::ASTUnit(bool _MainFileIsAST)
-  : CaptureDiagnostics(false), MainFileIsAST(_MainFileIsAST), 
+  : OnlyLocalDecls(false), CaptureDiagnostics(false),
+    MainFileIsAST(_MainFileIsAST), 
     CompleteTranslationUnit(true), WantTiming(getenv("LIBCLANG_TIMING")),
     OwnsRemappedFileBuffers(true),
     NumStoredDiagnosticsFromDriver(0),
@@ -1522,6 +1523,19 @@ llvm::StringRef ASTUnit::getMainFileName() const {
   return Invocation->getFrontendOpts().Inputs[0].second;
 }
 
+ASTUnit *ASTUnit::create(CompilerInvocation *CI,
+                         llvm::IntrusiveRefCntPtr<Diagnostic> Diags) {
+  llvm::OwningPtr<ASTUnit> AST;
+  AST.reset(new ASTUnit(false));
+  ConfigureDiags(Diags, 0, 0, *AST, /*CaptureDiagnostics=*/false);
+  AST->Diagnostics = Diags;
+  AST->Invocation.reset(CI);
+  AST->FileMgr.reset(new FileManager(CI->getFileSystemOpts()));
+  AST->SourceMgr.reset(new SourceManager(*Diags, *AST->FileMgr));
+
+  return AST.take();
+}
+
 bool ASTUnit::LoadFromCompilerInvocation(bool PrecompilePreamble) {
   if (!Invocation)
     return true;
@@ -2148,7 +2162,16 @@ bool ASTUnit::Save(llvm::StringRef File) {
                            llvm::raw_fd_ostream::F_Binary);
   if (!ErrorInfo.empty() || Out.has_error())
     return true;
-  
+
+  serialize(Out);
+  Out.close();
+  return Out.has_error();
+}
+
+bool ASTUnit::serialize(llvm::raw_ostream &OS) {
+  if (getDiagnostics().hasErrorOccurred())
+    return true;
+
   std::vector<unsigned char> Buffer;
   llvm::BitstreamWriter Stream(Buffer);
   ASTWriter Writer(Stream);
@@ -2156,7 +2179,7 @@ bool ASTUnit::Save(llvm::StringRef File) {
   
   // Write the generated bitstream to "Out".
   if (!Buffer.empty())
-    Out.write((char *)&Buffer.front(), Buffer.size());  
-  Out.close();
-  return Out.has_error();
+    OS.write((char *)&Buffer.front(), Buffer.size());
+
+  return false;
 }
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 8f99403923..d8de7c08b4 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -704,6 +704,10 @@ static void PreprocessorOptsToArgs(const PreprocessorOptions &Opts,
       assert(Opts.ImplicitPTHInclude == Opts.TokenCache &&
              "Unsupported option combination!");
   }
+  for (unsigned i = 0, e = Opts.ChainedIncludes.size(); i != e; ++i) {
+    Res.push_back("-chain-include");
+    Res.push_back(Opts.ChainedIncludes[i]);
+  }
   for (unsigned i = 0, e = Opts.RemappedFiles.size(); i != e; ++i) {
     Res.push_back("-remap-file");
     Res.push_back(Opts.RemappedFiles[i].first + ";" +
@@ -1562,6 +1566,12 @@ static void ParsePreprocessorArgs(PreprocessorOptions &Opts, ArgList &Args,
       Opts.Includes.push_back(A->getValue(Args));
   }
 
+  for (arg_iterator it = Args.filtered_begin(OPT_chain_include),
+         ie = Args.filtered_end(); it != ie; ++it) {
+    const Arg *A = *it;
+    Opts.ChainedIncludes.push_back(A->getValue(Args));
+  }
+
   // Include 'altivec.h' if -faltivec option present
   if (Args.hasArg(OPT_faltivec))
     Opts.Includes.push_back("altivec.h");
diff --git a/lib/Frontend/FrontendAction.cpp b/lib/Frontend/FrontendAction.cpp
index e3d8b85941..5c34e9491b 100644
--- a/lib/Frontend/FrontendAction.cpp
+++ b/lib/Frontend/FrontendAction.cpp
@@ -20,6 +20,7 @@
 #include "clang/Frontend/MultiplexConsumer.h"
 #include "clang/Parse/ParseAST.h"
 #include "clang/Serialization/ASTDeserializationListener.h"
+#include "clang/Serialization/ChainedIncludesSource.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -209,8 +210,16 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
 
     CI.getASTContext().setASTMutationListener(Consumer->GetASTMutationListener());
 
-    /// Use PCH?
-    if (!CI.getPreprocessorOpts().ImplicitPCHInclude.empty()) {
+    if (!CI.getPreprocessorOpts().ChainedIncludes.empty()) {
+      // Convert headers to PCH and chain them.
+      llvm::OwningPtr<ExternalASTSource> source;
+      source.reset(ChainedIncludesSource::create(CI));
+      if (!source)
+        goto failure;
+      CI.getASTContext().setExternalSource(source);
+
+    } else if (!CI.getPreprocessorOpts().ImplicitPCHInclude.empty()) {
+      // Use PCH.
       assert(hasPCHSupport() && "This action does not have PCH support!");
       ASTDeserializationListener *DeserialListener
           = CI.getInvocation().getFrontendOpts().ChainedPCH ?