5 files changed, 50 insertions, 6 deletions

diff --git a/clang/include/clang/Serialization/ASTBitCodes.h b/clang/include/clang/Serialization/ASTBitCodes.h
index 3233a83931c..3d234d90859 100644
--- a/clang/include/clang/Serialization/ASTBitCodes.h
+++ b/clang/include/clang/Serialization/ASTBitCodes.h
@@ -448,7 +448,11 @@ namespace clang {
       OBJC_CHAINED_CATEGORIES,
 
       /// \brief Record code for a file sorted array of DeclIDs in a module.
-      FILE_SORTED_DECLS
+      FILE_SORTED_DECLS,
+      
+      /// \brief Record code for an array of all of the (sub)modules that were
+      /// imported by the AST file.
+      IMPORTED_MODULES
     };
 
     /// \brief Record types used within a source manager block.
diff --git a/clang/include/clang/Serialization/ASTReader.h b/clang/include/clang/Serialization/ASTReader.h
index e984e306c8d..203abe403cb 100644
--- a/clang/include/clang/Serialization/ASTReader.h
+++ b/clang/include/clang/Serialization/ASTReader.h
@@ -541,6 +541,9 @@ private:
   /// \brief A list of the namespaces we've seen.
   SmallVector<uint64_t, 4> KnownNamespaces;
 
+  /// \brief A list of modules that were imported by precompiled headers or
+  /// any other non-module AST file.
+  SmallVector<serialization::SubmoduleID, 2> ImportedModules;
   //@}
 
   /// \brief The original file name that was used to build the primary AST file,
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 22e34d62af4..c7b6b512a5d 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -2385,6 +2385,20 @@ ASTReader::ReadASTBlock(ModuleFile &F) {
       for (unsigned I = 0, N = Record.size(); I != N; ++I)
         KnownNamespaces.push_back(getGlobalDeclID(F, Record[I]));
       break;
+        
+    case IMPORTED_MODULES: {
+      if (F.Kind != MK_Module) {
+        // If we aren't loading a module (which has its own exports), make
+        // all of the imported modules visible.
+        // FIXME: Deal with macros-only imports.
+        for (unsigned I = 0, N = Record.size(); I != N; ++I) {
+          if (unsigned GlobalID = getGlobalSubmoduleID(F, Record[I]))
+            ImportedModules.push_back(GlobalID);
+        }
+      }
+      break;
+      
+    }
     }
   }
   Error("premature end of bitstream in AST file");
@@ -2835,6 +2849,13 @@ void ASTReader::InitializeContext() {
     Context.setcudaConfigureCallDecl(
                            cast<FunctionDecl>(GetDecl(CUDASpecialDeclRefs[0])));
   }
+  
+  // Re-export any modules that were imported by a non-module AST file.
+  for (unsigned I = 0, N = ImportedModules.size(); I != N; ++I) {
+    if (Module *Imported = getSubmodule(ImportedModules[I]))
+      makeModuleVisible(Imported, Module::AllVisible);
+  }
+  ImportedModules.clear();
 }
 
 void ASTReader::finalizeForWriting() {
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 00dbfabb451..15db7050e98 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -3335,6 +3335,27 @@ void ASTWriter::WriteASTCore(Sema &SemaRef, MemorizeStatCalls *StatCalls,
        I != E; ++I)
     WriteDeclContextVisibleUpdate(*I);
 
+  // Write the submodules that were imported, if any.
+  RecordData ImportedModules;
+  for (ASTContext::import_iterator I = Context.local_import_begin(),
+                                IEnd = Context.local_import_end();
+       I != IEnd; ++I) {
+    assert(SubmoduleIDs.find(I->getImportedModule()) != SubmoduleIDs.end());
+    ImportedModules.push_back(SubmoduleIDs[I->getImportedModule()]);
+  }
+  if (!ImportedModules.empty()) {
+    // Sort module IDs.
+    llvm::array_pod_sort(ImportedModules.begin(), ImportedModules.end());
+    
+    // Unique module IDs.
+    ImportedModules.erase(std::unique(ImportedModules.begin(), 
+                                      ImportedModules.end()),
+                          ImportedModules.end());
+    
+    Stream.EmitRecord(IMPORTED_MODULES, ImportedModules);
+    ImportedModules.clear();
+  }
+  
   WriteDeclUpdatesBlocks();
   WriteDeclReplacementsBlock();
   WriteChainedObjCCategories();
diff --git a/clang/test/Modules/diamond-pch.c b/clang/test/Modules/diamond-pch.c
index f5b0faa424b..d0f45908cfa 100644
--- a/clang/test/Modules/diamond-pch.c
+++ b/clang/test/Modules/diamond-pch.c
@@ -3,11 +3,6 @@
 
 // in diamond-bottom.h: expected-note{{passing argument to parameter 'x' here}}
 
-// FIXME: The module import below shouldn't be necessary, because importing the
-// precompiled header should make all of the modules visible that were
-// visible when the PCH file was built.
-__import_module__ diamond_bottom;
-
 void test_diamond(int i, float f, double d, char c) {
   top(&i);
   left(&f);