Support debug info for using directives at global/namespace scope.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@180594 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 5a10602..bf67bd1 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -2819,7 +2819,6 @@
     // No code generation needed.
   case Decl::UsingShadow:
   case Decl::Using:
-  case Decl::UsingDirective:
   case Decl::ClassTemplate:
   case Decl::FunctionTemplate:
   case Decl::TypeAliasTemplate:
@@ -2827,6 +2826,10 @@
   case Decl::Block:
   case Decl::Empty:
     break;
+  case Decl::UsingDirective: // using namespace X; [C++]
+    if (CGDebugInfo *DI = getModuleDebugInfo())
+      DI->EmitUsingDirective(cast<UsingDirectiveDecl>(*D));
+    return;
   case Decl::CXXConstructor:
     // Skip function templates
     if (cast<FunctionDecl>(D)->getDescribedFunctionTemplate() ||