4 files changed, 37 insertions, 4 deletions
diff --git a/lib/Frontend/FrontendActions.cpp b/lib/Frontend/FrontendActions.cpp
index 24960cf6a0..f4ea5d3da0 100644
--- a/lib/Frontend/FrontendActions.cpp
+++ b/lib/Frontend/FrontendActions.cpp
@@ -132,7 +132,7 @@ ASTConsumer *GenerateModuleAction::CreateASTConsumer(CompilerInstance &CI,
 }
 
 /// \brief Collect the set of header includes needed to construct the given 
-/// module.
+/// module and update the TopHeaders file set of the module.
 ///
 /// \param Module The module we're collecting includes from.
 ///
@@ -149,15 +149,18 @@ static void collectModuleHeaderIncludes(const LangOptions &LangOpts,
 
   // Add includes for each of these headers.
   for (unsigned I = 0, N = Module->Headers.size(); I != N; ++I) {
+    const FileEntry *Header = Module->Headers[I];
+    Module->TopHeaders.insert(Header);
     if (LangOpts.ObjC1)
       Includes += "#import \"";
     else
       Includes += "#include \"";
-    Includes += Module->Headers[I]->getName();
+    Includes += Header->getName();
     Includes += "\"\n";
   }
 
   if (const FileEntry *UmbrellaHeader = Module->getUmbrellaHeader()) {
+    Module->TopHeaders.insert(UmbrellaHeader);
     if (Module->Parent) {
       // Include the umbrella header for submodules.
       if (LangOpts.ObjC1)
@@ -184,9 +187,11 @@ static void collectModuleHeaderIncludes(const LangOptions &LangOpts,
       
       // If this header is marked 'unavailable' in this module, don't include 
       // it.
-      if (const FileEntry *Header = FileMgr.getFile(Dir->path()))
+      if (const FileEntry *Header = FileMgr.getFile(Dir->path())) {
         if (ModMap.isHeaderInUnavailableModule(Header))
           continue;
+        Module->TopHeaders.insert(Header);
+      }
       
       // Include this header umbrella header for submodules.
       if (LangOpts.ObjC1)
diff --git a/lib/Lex/ModuleMap.cpp b/lib/Lex/ModuleMap.cpp
index 5c9a9b4fef..a0caf03e77 100644
--- a/lib/Lex/ModuleMap.cpp
+++ b/lib/Lex/ModuleMap.cpp
@@ -152,6 +152,7 @@ Module *ModuleMap::findModuleForHeader(const FileEntry *File) {
         StringRef Name = llvm::sys::path::stem(File->getName());
         Result = findOrCreateModule(Name, Result, /*IsFramework=*/false,
                                     Explicit).first;
+        Result->TopHeaders.insert(File);
         
         // If inferred submodules export everything they import, add a 
         // wildcard to the set of exports.
diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index 79173f50c5..ff418caf9e 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -3230,7 +3230,23 @@ ASTReader::ASTReadResult ASTReader::ReadSubmoduleBlock(ModuleFile &F) {
       }
       break;      
     }
-        
+
+    case SUBMODULE_TOPHEADER: {
+      if (First) {
+        Error("missing submodule metadata record at beginning of block");
+        return Failure;
+      }
+
+      if (!CurrentModule)
+        break;
+
+      // FIXME: Be more lazy about this!
+      StringRef FileName(BlobStart, BlobLen);
+      if (const FileEntry *File = PP.getFileManager().getFile(FileName))
+        CurrentModule->TopHeaders.insert(File);
+      break;
+    }
+
     case SUBMODULE_UMBRELLA_DIR: {
       if (First) {
         Error("missing submodule metadata record at beginning of block");
diff --git a/lib/Serialization/ASTWriter.cpp b/lib/Serialization/ASTWriter.cpp
index 59061792af..b8a0c28938 100644
--- a/lib/Serialization/ASTWriter.cpp
+++ b/lib/Serialization/ASTWriter.cpp
@@ -1952,6 +1952,11 @@ void ASTWriter::WriteSubmodules(Module *WritingModule) {
   unsigned HeaderAbbrev = Stream.EmitAbbrev(Abbrev);
 
   Abbrev = new BitCodeAbbrev();
+  Abbrev->Add(BitCodeAbbrevOp(SUBMODULE_TOPHEADER));
+  Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob)); // Name
+  unsigned TopHeaderAbbrev = Stream.EmitAbbrev(Abbrev);
+
+  Abbrev = new BitCodeAbbrev();
   Abbrev->Add(BitCodeAbbrevOp(SUBMODULE_UMBRELLA_DIR));
   Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob)); // Name
   unsigned UmbrellaDirAbbrev = Stream.EmitAbbrev(Abbrev);
@@ -2022,6 +2027,12 @@ void ASTWriter::WriteSubmodules(Module *WritingModule) {
       Stream.EmitRecordWithBlob(HeaderAbbrev, Record, 
                                 Mod->Headers[I]->getName());
     }
+    for (unsigned I = 0, N = Mod->TopHeaders.size(); I != N; ++I) {
+      Record.clear();
+      Record.push_back(SUBMODULE_TOPHEADER);
+      Stream.EmitRecordWithBlob(TopHeaderAbbrev, Record,
+                                Mod->TopHeaders[I]->getName());
+    }
 
     // Emit the imports. 
     if (!Mod->Imports.empty()) {