Debug Info: In DIBuilder, the context field of a global variable is updated to

use DIScopeRef.

A paired commit at clang will follow to show cases where we will use an
identifer for the context of a global variable.

rdar://18958417


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222195 91177308-0d34-0410-b5e6-96231b3b80d8

lib/IR/DIBuilder.cpp

@@ -844,7 +844,7 @@ static DIGlobalVariable createGlobalVariableHelper(
                        .concat(isLocalToUnit)
                        .concat(isDefinition)
                        .get(VMContext),
-                   getNonCompileUnitScope(Context), F, Ty, Val,
+                   DIScope(getNonCompileUnitScope(Context)).getRef(), F, Ty, Val,
                    DIDescriptor(Decl)};
 
   return DIGlobalVariable(CreateFunc(Elts));