Fix additional spec violations wrt RegExp.lastIndex.

src/string.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 176 matching lines @@
   var subject = TO_STRING_INLINE(this);
   if (IS_REGEXP(regexp)) {
     // Emulate RegExp.prototype.exec's side effect in step 5, even though
     // value is discarded.
     ToInteger(regexp.lastIndex);
     if (!regexp.global) return RegExpExecNoTests(regexp, subject, 0);
     %_Log('regexp', 'regexp-match,%0S,%1r', [subject, regexp]);
     // lastMatchInfo is defined in regexp.js.
     var result = %StringMatch(subject, regexp, lastMatchInfo);
     if (result !== null) lastMatchInfoOverride = null;
+    regexp.lastIndex = 0;
     return result;
   }
   // Non-regexp argument.
   regexp = new $RegExp(regexp);
   return RegExpExecNoTests(regexp, subject, 0);
 }
 
 
 // SubString is an internal function that returns the sub string of 'string'.
 // If resulting string is of length 1, we use the one character cache
@@ skipping 30 matching lines @@
     if (IS_SPEC_FUNCTION(replace)) {
       if (search.global) {
         return StringReplaceGlobalRegExpWithFunction(subject, search, replace);
       } else {
         return StringReplaceNonGlobalRegExpWithFunction(subject,
                                                         search,
                                                         replace);
       }
     } else {
       if (lastMatchInfoOverride == null) {
-        return %StringReplaceRegExpWithString(subject,
-                                              search,
-                                              TO_STRING_INLINE(replace),
-                                              lastMatchInfo);
+        var answer = %StringReplaceRegExpWithString(subject,
+                                                    search,
+                                                    TO_STRING_INLINE(replace),
+                                                    lastMatchInfo);
+        if (IS_UNDEFINED(answer)) {  // No match.  Return subject string.
+          search.lastIndex = 0;
+          return subject;
+        }
+        if (search.global) search.lastIndex = 0;
+        return answer;
       } else {
         // We use this hack to detect whether StringReplaceRegExpWithString
-        // found at least one hit.  In that case we need to remove any
+        // found at least one hit. In that case we need to remove any
         // override.
         var saved_subject = lastMatchInfo[LAST_SUBJECT_INDEX];
         lastMatchInfo[LAST_SUBJECT_INDEX] = 0;
         var answer = %StringReplaceRegExpWithString(subject,
                                                     search,
                                                     TO_STRING_INLINE(replace),
                                                     lastMatchInfo);
+        if (IS_UNDEFINED(answer)) {  // No match.  Return subject string.
+          search.lastIndex = 0;
+          lastMatchInfo[LAST_SUBJECT_INDEX] = saved_subject;
+          return subject;
+        }
         if (%_IsSmi(lastMatchInfo[LAST_SUBJECT_INDEX])) {
           lastMatchInfo[LAST_SUBJECT_INDEX] = saved_subject;
         } else {
           lastMatchInfoOverride = null;
         }
+        if (search.global) search.lastIndex = 0;
         return answer;
       }
     }
   }
 
   // Convert the search argument to a string and search for it.
   search = TO_STRING_INLINE(search);
   if (search.length == 1 &&
       subject.length > 0xFF &&
       IS_STRING(replace) &&
@@ skipping 726 matching lines @@
     "fixed", StringFixed,
     "italics", StringItalics,
     "small", StringSmall,
     "strike", StringStrike,
     "sub", StringSub,
     "sup", StringSup
   ));
 }
 
 SetUpString();