[es6] re-implement rest parameters via desugaring

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'.
 
@@ skipping 45 matching lines @@
 var CONCAT_ITERABLE_TO_ARRAY;
 var APPLY_PREPARE;
 var REFLECT_APPLY_PREPARE;
 var REFLECT_CONSTRUCT_PREPARE;
 var STACK_OVERFLOW;
 var TO_OBJECT;
 var TO_NUMBER;
 var TO_STRING;
 var TO_NAME;
 
+var $createEmptyArray;
 var $defaultNumber;
 var $defaultString;
 var $NaN;
 var $nonNumberToNumber;
 var $nonStringToString;
 var $sameValue;
 var $sameValueZero;
 var $toBoolean;
 var $toInt32;
 var $toInteger;
@@ skipping 883 matching lines @@
   }
   throw MakeTypeError(kCannotConvertToPrimitive);
 }
 
 function ToPositiveInteger(x, rangeErrorIndex) {
   var i = TO_INTEGER_MAP_MINUS_ZERO(x);
   if (i < 0) throw MakeRangeError(rangeErrorIndex);
   return i;
 }
 
+function CreateEmptyArray() {
+  return [];
+}
+
 //----------------------------------------------------------------------------
 
 // NOTE: Setting the prototype for Array must take place as early as
 // possible due to code generation for array literals.  When
 // generating code for a array literal a boilerplate array is created
 // that is cloned when running the code.  It is essential that the
 // boilerplate gets the right prototype.
 %FunctionSetPrototype(GlobalArray, new GlobalArray(0));
 
 //----------------------------------------------------------------------------
@@ skipping 10 matching lines @@
 $toInt32 = ToInt32;
 $toInteger = ToInteger;
 $toLength = ToLength;
 $toName = ToName;
 $toNumber = ToNumber;
 $toObject = ToObject;
 $toPositiveInteger = ToPositiveInteger;
 $toPrimitive = ToPrimitive;
 $toString = ToString;
 $toUint32 = ToUint32;
-
+$createEmptyArray = CreateEmptyArray;
 })