Added support for generate DWARF .debug_aranges sections automatically.

llvm-svn: 191052
diff --git a/llvm/lib/MC/MCNullStreamer.cpp b/llvm/lib/MC/MCNullStreamer.cpp
index 87a7db6..2ddc4f0 100644
--- a/llvm/lib/MC/MCNullStreamer.cpp
+++ b/llvm/lib/MC/MCNullStreamer.cpp
@@ -37,7 +37,7 @@
     virtual void EmitLabel(MCSymbol *Symbol) {
       assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
       assert(getCurrentSection().first &&"Cannot emit before setting section!");
-      Symbol->setSection(*getCurrentSection().first);
+      AssignSection(Symbol, getCurrentSection().first);
     }
     virtual void EmitDebugLabel(MCSymbol *Symbol) {
       EmitLabel(Symbol);