Native construction of RegExp result objects, with in-object index and input.

src/string.js

 // Copyright 2006-2009 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 131 matching lines @@
       }
     }
   }
   if (index < 0) {
     return -1;
   }
   return %StringLastIndexOf(sub, pat, index);
 }
 
 
+function CloneDenseArray(array) {
+  if (array === null) return null;
+  var clone = new $Array(array.length);
+  for (var i = 0; i < array.length; i++) {
+    clone[i] = array[i];
+  }
+  return clone;
+}
+
+
 // ECMA-262 section 15.5.4.9
 //
 // This function is implementation specific.  For now, we do not
 // do anything locale specific.
 function StringLocaleCompare(other) {
   if (%_ArgumentsLength() === 0) return 0;
 
   var this_str = TO_STRING_INLINE(this);
   var other_str = TO_STRING_INLINE(other);
   return %StringLocaleCompare(this_str, other_str);
 }
 
 
 // ECMA-262 section 15.5.4.10
 function StringMatch(regexp) {
-  if (!IS_REGEXP(regexp)) regexp = new $RegExp(regexp);
   var subject = TO_STRING_INLINE(this);
+  if (IS_REGEXP(regexp)) { 
+    if (!regexp.global) return regexp.exec(subject); 
+    
+    var cache = regExpCache;
+    var saveAnswer = false;
 
-  if (!regexp.global) return regexp.exec(subject);
-
-  var cache = regExpCache;
-  var saveAnswer = false;
-
-  if (%_ObjectEquals(cache.type, 'match') &&
-      %_ObjectEquals(cache.regExp, regexp) &&
-      %_ObjectEquals(cache.subject, subject)) {
-    if (cache.answerSaved) {
-      return CloneRegexpAnswer(cache.answer);
-    } else {
-      saveAnswer = true;
+    if (%_ObjectEquals(cache.type, 'match') &&
+        %_ObjectEquals(cache.regExp, regexp) &&
+        %_ObjectEquals(cache.subject, subject)) {
+      if (cache.answerSaved) {
+        return CloneDenseArray(cache.answer);
+      } else {
+        saveAnswer = true;
+      }
     }
+    %_Log('regexp', 'regexp-match,%0S,%1r', [subject, regexp]);
+    // lastMatchInfo is defined in regexp.js.
+    var result = %StringMatch(subject, regexp, lastMatchInfo);
+    cache.type = 'match';
+    cache.regExp = regexp;
+    cache.subject = subject;
+    if (saveAnswer) cache.answer = CloneDenseArray(result);
+    cache.answerSaved = saveAnswer;
+    return result;
   }
-
-  %_Log('regexp', 'regexp-match,%0S,%1r', [subject, regexp]);
-  // lastMatchInfo is defined in regexp.js.
-  var result = %StringMatch(subject, regexp, lastMatchInfo);
-  cache.type = 'match';
-  cache.regExp = regexp;
-  cache.subject = subject;
-  if (saveAnswer) cache.answer = CloneRegexpAnswer(result);
-  cache.answerSaved = saveAnswer;
-  return result;
+  // Non-regexp argument.
+  regexp = new $RegExp(regexp);
+  // Don't check regexp exec cache, since the regexp is new.
+  // TODO(lrn): Change this if we start caching regexps here.
+  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
 // otherwise we call the runtime system.
 function SubString(string, start, end) {
   // Use the one character string cache.
   if (start + 1 == end) {
     var char_code = %_FastCharCodeAt(string, start);
@@ skipping 388 matching lines @@
     return result;
   }
 
   var cache = regExpCache;
   var saveAnswer = false;
 
   if (%_ObjectEquals(cache.type, 'split') &&
       %_ObjectEquals(cache.regExp, separator) &&
       %_ObjectEquals(cache.subject, subject)) {
     if (cache.answerSaved) {
-      return CloneRegexpAnswer(cache.answer);
+      return CloneDenseArray(cache.answer);
     } else {
       saveAnswer = true;
     }
   }
 
   cache.type = 'split';
   cache.regExp = separator;
   cache.subject = subject;
 
   %_Log('regexp', 'regexp-split,%0S,%1r', [subject, separator]);
@@ skipping 45 matching lines @@
       if (start != -1 && end != -1) {
         result[result.length] = SubString(subject, start, end);
       } else {
         result[result.length] = void 0;
       }
       if (result.length === limit) break outer_loop;
     }
 
     startIndex = currentIndex = endIndex;
   }
-  if (saveAnswer) cache.answer = CloneRegexpAnswer(result);
+  if (saveAnswer) cache.answer = CloneDenseArray(result);
   cache.answerSaved = saveAnswer;
   return result;
-  
 }
 
 
 // ECMA-262 section 15.5.4.14
 // Helper function used by split.  This version returns the matchInfo
 // instead of allocating a new array with basically the same information.
 function splitMatch(separator, subject, current_index, start_index) {
   var matchInfo = DoRegExpExec(separator, subject, start_index);
   if (matchInfo == null) return null;
   // Section 15.5.4.14 paragraph two says that we do not allow zero length
@@ skipping 303 matching lines @@
     "small", StringSmall,
     "strike", StringStrike,
     "sub", StringSub,
     "sup", StringSup,
     "toJSON", StringToJSON
   ));
 }
 
 
 SetupString();