RegExp: remove last match info override.

src/js/string.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 (function(global, utils) {
 
 %CheckIsBootstrapping();
 
 // -------------------------------------------------------------------
 // Imports
@@ skipping 139 matching lines @@
 
 
 // ECMA-262 section 15.5.4.10
 function StringMatchJS(regexp) {
   CHECK_OBJECT_COERCIBLE(this, "String.prototype.match");
 
   var subject = TO_STRING(this);
   if (IS_REGEXP(regexp)) {
     if (!regexp.global) return RegExpExecNoTests(regexp, subject, 0);
     var result = %StringMatch(subject, regexp, RegExpLastMatchInfo);
-    if (result !== null) $regexpLastMatchInfoOverride = null;
     regexp.lastIndex = 0;
     return result;
   }
   // Non-regexp argument.
   regexp = new GlobalRegExp(regexp);
   return RegExpExecNoTests(regexp, subject, 0);
 }
 
 
 // ECMA-262 v6, section 21.1.3.12
@@ skipping 66 matching lines @@
           return %_SubString(subject, 0, match[CAPTURE0]) +
                  %_SubString(subject, match[CAPTURE1], subject.length)
         }
         return ExpandReplacement(replace, subject, RegExpLastMatchInfo,
                                  %_SubString(subject, 0, match[CAPTURE0])) +
                %_SubString(subject, match[CAPTURE1], subject.length);
       }
 
       // Global regexp search, string replace.
       search.lastIndex = 0;
-      if ($regexpLastMatchInfoOverride == null) {
-        return %StringReplaceGlobalRegExpWithString(
-            subject, search, replace, RegExpLastMatchInfo);
-      } else {
-        // We use this hack to detect whether StringReplaceRegExpWithString
-        // found at least one hit. In that case we need to remove any
-        // override.
-        var saved_subject = RegExpLastMatchInfo[LAST_SUBJECT_INDEX];
-        RegExpLastMatchInfo[LAST_SUBJECT_INDEX] = 0;
-        var answer = %StringReplaceGlobalRegExpWithString(
-            subject, search, replace, RegExpLastMatchInfo);
-        if (%_IsSmi(RegExpLastMatchInfo[LAST_SUBJECT_INDEX])) {
-          RegExpLastMatchInfo[LAST_SUBJECT_INDEX] = saved_subject;
-        } else {
-          $regexpLastMatchInfoOverride = null;
-        }
-        return answer;
-      }
+      return %StringReplaceGlobalRegExpWithString(
+          subject, search, replace, RegExpLastMatchInfo);
     }
 
     if (search.global) {
       // Global regexp search, function replace.
       return StringReplaceGlobalRegExpWithFunction(subject, search, replace);
     }
     // Non-global regexp search, function replace.
     return StringReplaceNonGlobalRegExpWithFunction(subject, search, replace);
   }
 
@@ skipping 156 matching lines @@
   }
   var len = res.length;
   if (NUMBER_OF_CAPTURES(RegExpLastMatchInfo) == 2) {
     // If the number of captures is two then there are no explicit captures in
     // the regexp, just the implicit capture that captures the whole match.  In
     // this case we can simplify quite a bit and end up with something faster.
     // The builder will consist of some integers that indicate slices of the
     // input string and some replacements that were returned from the replace
     // function.
     var match_start = 0;
-    var override = new InternalPackedArray(null, 0, subject);
     for (var i = 0; i < len; i++) {
       var elem = res[i];
       if (%_IsSmi(elem)) {
-        // Integers represent slices of the original string.  Use these to
-        // get the offsets we need for the override array (so things like
-        // RegExp.leftContext work during the callback function.
+        // Integers represent slices of the original string.
         if (elem > 0) {
           match_start = (elem >> 11) + (elem & 0x7ff);
         } else {
           match_start = res[++i] - elem;
         }
       } else {
-        override[0] = elem;
-        override[1] = match_start;
-        $regexpLastMatchInfoOverride = override;
         var func_result = replace(elem, match_start, subject);
         // Overwrite the i'th element in the results with the string we got
         // back from the callback function.
         res[i] = TO_STRING(func_result);
         match_start += elem.length;
       }
     }
   } else {
     for (var i = 0; i < len; i++) {
       var elem = res[i];
       if (!%_IsSmi(elem)) {
         // elem must be an Array.
         // Use the apply argument as backing for global RegExp properties.
-        $regexpLastMatchInfoOverride = elem;
         var func_result = %Apply(replace, UNDEFINED, elem, 0, elem.length);
         // Overwrite the i'th element in the results with the string we got
         // back from the callback function.
         res[i] = TO_STRING(func_result);
       }
     }
   }
-  var result = %StringBuilderConcat(res, res.length, subject);
+  var result = %StringBuilderConcat(res, len, subject);
   resultArray.length = 0;
   reusableReplaceArray = resultArray;
   return result;
 }
 
 
 function StringReplaceNonGlobalRegExpWithFunction(subject, regexp, replace) {
   var matchInfo = RegExpExec(regexp, subject, 0);
   if (IS_NULL(matchInfo)) {
     regexp.lastIndex = 0;
@@ skipping 705 matching lines @@
   to.StringLastIndexOf = StringLastIndexOfJS;
   to.StringMatch = StringMatchJS;
   to.StringReplace = StringReplace;
   to.StringSlice = StringSlice;
   to.StringSplit = StringSplitJS;
   to.StringSubstr = StringSubstr;
   to.StringSubstring = StringSubstring;
 });
 
 })