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/DIE.h b/lib/CodeGen/AsmPrinter/DIE.h
index d073da7..dc6a70a 100644
--- a/lib/CodeGen/AsmPrinter/DIE.h
+++ b/lib/CodeGen/AsmPrinter/DIE.h
@@ -277,9 +277,9 @@
   /// DIEString - A string value DIE.
   ///
   class DIEString : public DIEValue {
-    const std::string Str;
+    const StringRef Str;
   public:
-    explicit DIEString(const std::string &S) : DIEValue(isString), Str(S) {}
+    explicit DIEString(const StringRef S) : DIEValue(isString), Str(S) {}
 
     /// EmitValue - Emit string value.
     ///