Implement support for precompiled headers, preambles, and serialized

"main" files that import modules. When loading any of these kinds of
AST files, we make the modules that were imported visible into the
translation unit that loaded the PCH file or preamble.

llvm-svn: 145737

2 files changed, 42 insertions, 0 deletions

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();