[builtins] Support SameValue and SameValueZero via runtime functions.

test/mjsunit/samevalue.js

 // Copyright 2010 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 15 matching lines @@
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 
 // Flags: --expose-natives-as natives
 // Test the SameValue and SameValueZero internal methods.
 
 var obj1 = {x: 10, y: 11, z: "test"};
 var obj2 = {x: 10, y: 11, z: "test"};
 
 var sameValue = Object.is;
-var sameValueZero = natives.ImportNow("SameValueZero");
+var sameValueZero = function(x, y) { return %SameValue(x, y); }

[Michael Starzinger, 2016/02/17 09:44:21]

Shouldn't this be %SameValueZero here?

[Benedikt Meurer, 2016/02/17 10:20:26]

Done.

 
 // Calls SameValue and SameValueZero and checks that their results match.
 function sameValueBoth(a, b) {
   var result = sameValue(a, b);
   assertTrue(result === sameValueZero(a, b));
   return result;
 }
 
 // Calls SameValue and SameValueZero and checks that their results don't match.
 function sameValueZeroOnly(a, b) {
@@ skipping 64 matching lines @@
 assertFalse(sameValueBoth("1", 1));
 assertFalse(sameValueBoth("true", true));
 assertFalse(sameValueBoth("false", false));
 assertFalse(sameValueBoth("undefined", undefined));
 assertFalse(sameValueBoth("NaN", NaN));
 
 // SameValue considers -0 and +0 to be different; SameValueZero considers
 // -0 and +0 to be the same.
 assertTrue(sameValueZeroOnly(+0, -0));
 assertTrue(sameValueZeroOnly(-0, +0));