2 files changed, 28 insertions, 1 deletions
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()) {