Merge bleeding_edge from version 2.1.3 up to revision 4205...

src/regexp.js

Index: src/regexp.js
===================================================================
--- src/regexp.js	(revision 4205)
+++ src/regexp.js	(working copy)
@@ -95,6 +95,7 @@
     %IgnoreAttributesAndSetProperty(object, 'ignoreCase', ignoreCase);
     %IgnoreAttributesAndSetProperty(object, 'multiline', multiline);
     %IgnoreAttributesAndSetProperty(object, 'lastIndex', 0);
+    regExpCache.type = 'none';
   }
 
   // Call internal function to compile the pattern.
@@ -140,11 +141,51 @@
 }
 
 
+function RegExpCache() {
+  this.type = 'none';
+  this.regExp = 0;
+  this.subject = 0;
+  this.replaceString = 0;
+  this.lastIndex = 0;
+  this.answer = 0;
+}
+
+
+var regExpCache = new RegExpCache();
+
+
+function CloneRegexpAnswer(array) {
+  var len = array.length;
+  var answer = new $Array(len);
+  for (var i = 0; i < len; i++) {
+    answer[i] = array[i];
+  }
+  answer.index = array.index;
+  answer.input = array.input;
+  return answer;
+}
+
+
 function RegExpExec(string) {
   if (!IS_REGEXP(this)) {
     throw MakeTypeError('incompatible_method_receiver',
                         ['RegExp.prototype.exec', this]);
   }
+
+  var cache = regExpCache;
+
+  if (%_ObjectEquals(cache.type, 'exec') &&
+      %_ObjectEquals(cache.lastIndex, this.lastIndex) &&
+      %_ObjectEquals(cache.regExp, this) &&
+      %_ObjectEquals(cache.subject, string)) {
+    var last = cache.answer;
+    if (last == null) {
+      return last;
+    } else {
+      return CloneRegexpAnswer(last);
+    }
+  }
+
   if (%_ArgumentsLength() == 0) {
     var regExpInput = LAST_INPUT(lastMatchInfo);
     if (IS_UNDEFINED(regExpInput)) {
@@ -159,6 +200,7 @@
     s = ToString(string);
   }
   var lastIndex = this.lastIndex;
+
   var i = this.global ? TO_INTEGER(lastIndex) : 0;
 
   if (i < 0 || i > s.length) {
@@ -172,7 +214,12 @@
 
   if (matchIndices == null) {
     if (this.global) this.lastIndex = 0;
-    return matchIndices; // no match
+    cache.lastIndex = lastIndex;
+    cache.regExp = this;
+    cache.subject = s;
+    cache.answer = matchIndices;  // Null.
+    cache.type = 'exec';
+    return matchIndices;        // No match.
   }
 
   var numResults = NUMBER_OF_CAPTURES(lastMatchInfo) >> 1;
@@ -196,11 +243,19 @@
     }
   }
 
-  if (this.global)
-    this.lastIndex = lastMatchInfo[CAPTURE1];
   result.index = lastMatchInfo[CAPTURE0];
   result.input = s;
-  return result;
+  if (this.global) {
+    this.lastIndex = lastMatchInfo[CAPTURE1];
+    return result;
+  } else {
+    cache.regExp = this;
+    cache.subject = s;
+    cache.lastIndex = lastIndex;
+    cache.answer = result;
+    cache.type = 'exec';
+    return CloneRegexpAnswer(result);
+  }
 }
 
 
@@ -220,13 +275,35 @@
     }
     string = regExpInput;
   }
-  var s = ToString(string);
+  var s;
+  if (IS_STRING(string)) {
+    s = string;
+  } else {
+    s = ToString(string);
+  }
+
+  var lastIndex = this.lastIndex;
+
+  var cache = regExpCache;
+
+  if (%_ObjectEquals(cache.type, 'test') &&
+      %_ObjectEquals(cache.regExp, this) &&
+      %_ObjectEquals(cache.subject, string) &&
+      %_ObjectEquals(cache.lastIndex, lastIndex)) {
+    return cache.answer;
+  }
+
   var length = s.length;
-  var lastIndex = this.lastIndex;
   var i = this.global ? TO_INTEGER(lastIndex) : 0;
 
+  cache.type = 'test';
+  cache.regExp = this;
+  cache.subject = s;
+  cache.lastIndex = i;
+
   if (i < 0 || i > s.length) {
     this.lastIndex = 0;
+    cache.answer = false;
     return false;
   }
 
@@ -236,10 +313,12 @@
 
   if (matchIndices == null) {
     if (this.global) this.lastIndex = 0;
+    cache.answer = false;
     return false;
   }
 
   if (this.global) this.lastIndex = lastMatchInfo[CAPTURE1];
+  cache.answer = true;
   return true;
 }
 
@@ -358,6 +437,7 @@
     return IS_UNDEFINED(regExpInput) ? "" : regExpInput;
   }
   function RegExpSetInput(string) {
+    regExpCache.type = 'none';
     LAST_INPUT(lastMatchInfo) = ToString(string);
   };