Index: lib/ubsan/ubsan_diag.cc
===================================================================
--- lib/ubsan/ubsan_diag.cc
+++ lib/ubsan/ubsan_diag.cc
@@ -313,12 +313,12 @@
 
   switch (Level) {
   case DL_Error:
-    Printf("%s runtime error: %s%s",
+    Printf("%s UndefinedBehaviorSanitizer runtime error: %s%s",
            Decor.Warning(), Decor.EndWarning(), Decor.Bold());
     break;
 
   case DL_Note:
-    Printf("%s note: %s", Decor.Note(), Decor.EndNote());
+    Printf("%s UndefinedBehaviorSanitizer note: %s", Decor.Note(), Decor.EndNote());
     break;
   }