Use StringRef instead of std::string in DIEString.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89793 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 01d0e3c..19583b8 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -244,7 +244,7 @@
   /// addString - Add a string attribute data and value.
   ///
   void addString(DIE *Die, unsigned Attribute, unsigned Form,
-                 const std::string &String);
+                 const StringRef Str);
 
   /// addLabel - Add a Dwarf label attribute data and value.
   ///