Implement V8 extras utils object

src/prologue.js

Index: src/prologue.js
diff --git a/src/prologue.js b/src/prologue.js
index 5defb534d671d6e7c4a26577a82c5d0177e28dce..96da85859f4023120df2b68e1ec3d058f49537ad 100644
--- a/src/prologue.js
+++ b/src/prologue.js
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-(function(global, utils) {
+(function(global, utils, extrasUtils) {
 
 "use strict";
 
@@ -267,4 +267,57 @@ utils.PostDebug = PostDebug;
 
 %ToFastProperties(utils);
 
+// -----------------------------------------------------------------------
+
+%OptimizeObjectForAddingMultipleProperties(extrasUtils, 7);
+
+extrasUtils.logStackTrace = function logStackTrace() {
+  %DebugTrace();
+};
+
+extrasUtils.log = function log() {
+  let message = '';
+  for (const arg of arguments) {
+    message += arg;
+  }
+
+  %GlobalPrint(message);
+};
+
+// Extras need the ability to store private state on their objects without
+// exposing it to the outside world.
+
+extrasUtils.createPrivateSymbol = function createPrivateSymbol(name) {
+  return %CreatePrivateSymbol(name);
+};
+
+// These functions are key for safe meta-programming:
+// http://wiki.ecmascript.org/doku.php?id=conventions:safe_meta_programming
+//
+// Technically they could all be derived from combinations of
+// Function.prototype.{bind,call,apply} but that introduces lots of layers of
+// indirection and slowness given how un-optimized bind is.
+
+extrasUtils.call = function call(func, thisArg) {
+  return %Apply(func, thisArg, arguments, 2, arguments.length - 2);

[Yang, 2015/09/16 18:41:34]

%Apply should not be any faster than Function.prototype.apply iirc. So I'm not
sure exposing this here makes any sense. I would favor the alternative where the
extras code would grab Function.prototype.apply on initialization and use it. Is
there any downside to that alternative?

+};
+
+extrasUtils.apply = function apply(func, thisArg, args) {
+  return %Apply(func, thisArg, args, 0, args.length);
+};
+
+extrasUtils.simpleBind = function simpleBind(func, thisArg) {
+  return function() {
+    return %Apply(func, thisArg, arguments, 0, arguments.length);
+  };
+};
+
+extrasUtils.uncurryThis = function uncurryThis(func) {
+  return function(thisArg) {
+    return %Apply(func, thisArg, arguments, 1, arguments.length - 1);
+  };
+};
+
+%ToFastProperties(extrasUtils);
+
 })