diff --git a/llvm/lib/Support/StringExtras.cpp b/llvm/lib/Support/StringExtras.cpp
--- a/llvm/lib/Support/StringExtras.cpp
+++ b/llvm/lib/Support/StringExtras.cpp
@@ -67,7 +67,7 @@
     else if (isPrint(C) && C != '"')
       Out << C;
     else
-      Out << '\\' << hexdigit(C >> 4) << hexdigit(C & 0x0F);
+      Out << "\\x" << hexdigit(C >> 4) << hexdigit(C & 0x0F);
   }
 }