In the Module class, add a reference to the corresponding AST file.

llvm-svn: 164873
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index 6de1531..4cc46b8 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -980,6 +980,9 @@
       Module = PP->getHeaderSearchInfo().getModuleMap()
                  .findModule((Path[0].first->getName()));
     }
+
+    if (Module)
+      Module->setASTFile(ModuleFile);
     
     // Cache the result of this top-level module lookup for later.
     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;