PR14606: Debug info for using directives/DW_TAG_imported_module

More changes later for using declarations/DW_TAG_imported_declaration.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179837 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index dedf601..589528e 100644
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -2929,6 +2929,13 @@
                                 getStaticDataMemberDeclaration(VD));
 }
 
+void CGDebugInfo::EmitUsingDirective(const UsingDirectiveDecl &UD) {
+  DBuilder.createImportedModule(
+      getContextDescriptor(cast<Decl>(UD.getDeclContext())),
+      getOrCreateNameSpace(UD.getNominatedNamespace()),
+      getLineNumber(UD.getLocation()));
+}
+
 /// getOrCreateNamesSpace - Return namespace descriptor for the given
 /// namespace decl.
 llvm::DINameSpace