Faster invocation of custom comparator function.

src/array.js

 // Copyright 2006-2008 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 626 matching lines @@
 
   // Return the deleted elements.
   return deleted_elements;
 }
 
 
 function ArraySort(comparefn) {
   // In-place QuickSort algorithm.
   // For short (length <= 22) arrays, insertion sort is used for efficiency.
 
+  var global_receiver;
+
   function InsertionSortWithFunc(a, from, to) {
     for (var i = from + 1; i < to; i++) {
       var element = a[i];
       // place element in a[from..i[
       // binary search
       var min = from;
       var max = i;
       // The search interval is a[min..max[
       while (min < max) {
         var mid = min + ((max - min) >> 1);
-        var order = (a[mid] === element) ?
-            0 : comparefn.call(null, a[mid], element);
+        var order = %_CallFunction(global_receiver, a[mid], element, comparefn);
         if (order == 0) {
           min = max = mid;
           break;
         }
         if (order < 0) {
           min = mid + 1;
         } else {
           max = mid;
         }
       }
@@ skipping 16 matching lines @@
     // Issue 95: Keep the pivot element out of the comparisons to avoid
     // infinite recursion if comparefn(pivot, pivot) != 0.
     a[pivot_index] = a[from];
     a[from] = pivot;
     var low_end = from;   // Upper bound of the elements lower than pivot.
     var high_start = to;  // Lower bound of the elements greater than pivot.
     // From low_end to i are elements equal to pivot.
     // From i to high_start are elements that haven't been compared yet.
     for (var i = from + 1; i < high_start; ) {
       var element = a[i];
-      var order = (element === pivot) ?
-          0 : comparefn.call(null, element, pivot);
+      var order = %_CallFunction(global_receiver, element, pivot, comparefn);
       if (order < 0) {
         a[i] = a[low_end];
         a[low_end] = element;
         i++;
         low_end++;
       } else if (order > 0) {
         high_start--;
         a[i] = a[high_start];
         a[high_start] = element;
       } else {  // order == 0
@@ skipping 224 matching lines @@
 
   var num_non_undefined = %RemoveArrayHoles(this, length);
   if (num_non_undefined == -1) {
     // There were indexed accessors in the array.  Move array holes and
     // undefineds to the end using a Javascript function that is safe
     // in the presence of accessors.
     num_non_undefined = SafeRemoveArrayHoles(this);
   }
 
   if(IS_FUNCTION(comparefn)) {
+    global_receiver = %GetGlobalReceiver();
     QuickSortWithFunc(this, 0, num_non_undefined);
   } else {
     QuickSort(this, 0, num_non_undefined);
   }
 
   if (!is_array && (num_non_undefined + 1 < max_prototype_element)) {
     // For compatibility with JSC, we shadow any elements in the prototype
     // chain that has become exposed by sort moving a hole to its position.
     ShadowPrototypeElements(this, num_non_undefined, max_prototype_element);
   }
@@ skipping 259 matching lines @@
     "lastIndexOf", getFunction("lastIndexOf", ArrayLastIndexOf, 1),
     "reduce", getFunction("reduce", ArrayReduce, 1),
     "reduceRight", getFunction("reduceRight", ArrayReduceRight, 1)
   ));
 
   %FinishArrayPrototypeSetup($Array.prototype);
 }
 
 
 SetupArray();