DebugInfo: Sink DwarfDebug::ScopeVariables down into DwarfFile

(part of refactoring to allow subprogram emission in both the skeleton
and main units to enable -gmlt-like data to be included in the skeleton
for live inlined backtracing purposes)

llvm-svn: 220578
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index f1ee52d..6fff9ec 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -530,7 +530,7 @@
     unsigned *ChildScopeCount) {
   DIE *ObjectPointer = nullptr;
 
-  for (DbgVariable *DV : DD->getScopeVariables().lookup(Scope))
+  for (DbgVariable *DV : DU->getScopeVariables().lookup(Scope))
     Children.push_back(constructVariableDIE(*DV, *Scope, ObjectPointer));
 
   unsigned ChildCountWithoutScopes = Children.size();