Release stack trace data after firing Error.stack accessor.

src/messages.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 748 matching lines @@
 
 // ----------------------------------------------------------------------------
 // Error implementation
 
 // Defines accessors for a property that is calculated the first time
 // the property is read.
 function DefineOneShotAccessor(obj, name, fun) {
   // Note that the accessors consistently operate on 'obj', not 'this'.
   // Since the object may occur in someone else's prototype chain we
   // can't rely on 'this' being the same as 'obj'.
-  var hasBeenSet = false;
   var value;
+  var getter_function = fun;

[Vyacheslav Egorov (Google), 2012/08/28 16:43:43]

Is there any reason why you can't simply use fun without creating a separate
variable?

If there is one: please add a comment explaining that, otherwise: please use fun
[possibly renaming it into make_value, value_factory or something]

   var getter = function() {
-    if (hasBeenSet) {
+    if (getter_function == null) {
       return value;
     }
-    hasBeenSet = true;
-    value = fun(obj);
+    value = getter_function(obj);
+    getter_function = null;
     return value;
   };
   var setter = function(v) {
-    hasBeenSet = true;
+    getter_function = null;
     value = v;
   };
   %DefineOrRedefineAccessorProperty(obj, name, getter, setter, DONT_ENUM);
 }
 
 function CallSite(receiver, fun, pos) {
   this.receiver = receiver;
   this.fun = fun;
   this.pos = pos;
 }
@@ skipping 468 matching lines @@
     throw e;
   }
 }
 
 
 InstallFunctions($Error.prototype, DONT_ENUM, ['toString', ErrorToString]);
 
 // Boilerplate for exceptions for stack overflows. Used from
 // Isolate::StackOverflow().
 var kStackOverflowBoilerplate = MakeRangeError('stack_overflow', []);