ES6: Array.prototype.slice and friends should use ToLength instead of ToUint32

src/runtime.js

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This files contains runtime support implemented in JavaScript.
 
 // CAUTION: Some of the functions specified in this file are called
 // directly from compiled code. These are the functions with names in
 // ALL CAPS. The compiled code passes the first argument in 'this'.
 
 
 // The following declarations are shared with other native JS files.
 // They are all declared at this one spot to avoid redeclaration errors.
 var $defaultNumber;
 var $defaultString;
 var $NaN;
 var $nonNumberToNumber;
 var $nonStringToString;
 var $sameValue;
 var $sameValueZero;
 var $toInteger;
 var $toLength;
 var $toName;
 var $toNumber;
 var $toPositiveInteger;
 var $toPrimitive;
 var $toString;
 
+var harmony_tolength = false;
+
 (function(global, utils) {
 
 %CheckIsBootstrapping();
 
 var GlobalArray = global.Array;
 var GlobalBoolean = global.Boolean;
 var GlobalString = global.String;
 var GlobalNumber = global.Number;
 
 // ----------------------------------------------------------------------------
@@ skipping 666 matching lines @@
 
 
 // ES6, draft 08-24-14, section 7.1.15
 function ToLength(arg) {
   arg = ToInteger(arg);
   if (arg < 0) return 0;
   return arg < GlobalNumber.MAX_SAFE_INTEGER ? arg
                                              : GlobalNumber.MAX_SAFE_INTEGER;
 }
 
+function ToLengthFlagged(arg) {

[Camillo Bruni, 2015/09/08 07:18:07]

I would create a TO_LENGTH macro out of this (see src/macros.py).

[aperez, 2015/09/09 12:48:43]

Acknowledged.

+  return (harmony_tolength) ? ToLength(arg) : TO_UINT32(arg);
+}
 
 // ES5, section 9.12
 function SameValue(x, y) {
   if (typeof x != typeof y) return false;
   if (IS_NUMBER(x)) {
     if (NUMBER_IS_NAN(x) && NUMBER_IS_NAN(y)) return true;
     // x is +0 and y is -0 or vice versa.
     if (x === 0 && y === 0 && %_IsMinusZero(x) != %_IsMinusZero(y)) {
       return false;
     }
@@ skipping 171 matching lines @@
   "to_string_fun", ToString,
 ]);
 
 utils.Export(function(to) {
   to.ToBoolean = ToBoolean;
   to.ToLength = ToLength;
   to.ToName = ToName;
   to.ToNumber = ToNumber;
   to.ToPrimitive = ToPrimitive;
   to.ToString = ToString;
+  to.ToLengthFlagged = ToLengthFlagged;
 });
 
 })