Remove the nasty LABEL hack with a much less evil one. Now llvm.dbg.func.start implies a stoppoint is set. SelectionDAGISel records a new source line but does not create a ISD::LABEL node for this special stoppoint. Asm printer will magically print this label. This ensures nothing is emitted before.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46635 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/DwarfWriter.cpp

@@ -2721,6 +2721,11 @@ public:
     
     // Assumes in correct section after the entry point.
     EmitLabel("func_begin", ++SubprogramCount);
+
+    // Emit label for the implicitly defined dbg.stoppoint at the start of
+    // the function.
+    const SourceLineInfo &LineInfo = MMI->getSourceLines()[0];
+    Asm->printLabel(LineInfo.getLabelID());
   }
   
   /// EndFunction - Gather and emit post-function debug information.