Refactor the samevalue internal method and add tests for this method.

Noticing that the only difference between samevalue and strict equality is on
numbers we can simplify SameValue.

The old version did not return a correct answer if called on two strings since 
StringEquals (from runtime.cc) returns an answer that is the negated value 
(if treated as a boolean).


Review URL: http://codereview.chromium.org/2136024

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4713 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/runtime.js

@@ -559,19 +559,15 @@ function ToInt32(x) {
 // ES5, section 9.12
 function SameValue(x, y) {
   if (typeof x != typeof y) return false;
-  if (IS_NULL_OR_UNDEFINED(x)) return true;
   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 && (1 / x) != (1 / y)) {
       return false;
     }
-    return x == y;
+    return x === y;
   }
-  if (IS_STRING(x)) return %StringEquals(x, y);
-  if (IS_BOOLEAN(x)) return y == x;
-
-  return %_ObjectEquals(x, y);
+  return x === y
 }
 
 

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
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+// Flags: --expose-natives_as natives
+// Test the SameValue internal method.
+
+var obj1 = {x: 10, y: 11, z: "test"};
+var obj2 = {x: 10, y: 11, z: "test"};
+
+assertTrue(natives.SameValue(0, 0));
+assertTrue(natives.SameValue(+0, +0));
+assertTrue(natives.SameValue(-0, -0));
+assertTrue(natives.SameValue(1, 1));
+assertTrue(natives.SameValue(2, 2));
+assertTrue(natives.SameValue(-1, -1));
+assertTrue(natives.SameValue(0.5, 0.5));
+assertTrue(natives.SameValue(true, true));
+assertTrue(natives.SameValue(false, false));
+assertTrue(natives.SameValue(NaN, NaN));
+assertTrue(natives.SameValue(null, null));
+assertTrue(natives.SameValue("foo", "foo"));
+assertTrue(natives.SameValue(obj1, obj1));
+// Undefined values.
+assertTrue(natives.SameValue());
+assertTrue(natives.SameValue(undefined, undefined));
+
+assertFalse(natives.SameValue(0,1));
+assertFalse(natives.SameValue("foo", "bar"));
+assertFalse(natives.SameValue(obj1, obj2));
+assertFalse(natives.SameValue(true, false));
+
+assertFalse(natives.SameValue(obj1, true));
+assertFalse(natives.SameValue(obj1, "foo"));
+assertFalse(natives.SameValue(obj1, 1));
+assertFalse(natives.SameValue(obj1, undefined));
+assertFalse(natives.SameValue(obj1, NaN));
+
+assertFalse(natives.SameValue(undefined, true));
+assertFalse(natives.SameValue(undefined, "foo"));
+assertFalse(natives.SameValue(undefined, 1));
+assertFalse(natives.SameValue(undefined, obj1));
+assertFalse(natives.SameValue(undefined, NaN));
+
+assertFalse(natives.SameValue(NaN, true));
+assertFalse(natives.SameValue(NaN, "foo"));
+assertFalse(natives.SameValue(NaN, 1));
+assertFalse(natives.SameValue(NaN, obj1));
+assertFalse(natives.SameValue(NaN, undefined));
+
+assertFalse(natives.SameValue("foo", true));
+assertFalse(natives.SameValue("foo", 1));
+assertFalse(natives.SameValue("foo", obj1));
+assertFalse(natives.SameValue("foo", undefined));
+assertFalse(natives.SameValue("foo", NaN));
+
+assertFalse(natives.SameValue(true, 1));
+assertFalse(natives.SameValue(true, obj1));
+assertFalse(natives.SameValue(true, undefined));
+assertFalse(natives.SameValue(true, NaN));
+assertFalse(natives.SameValue(true, "foo"));
+
+assertFalse(natives.SameValue(1, true));
+assertFalse(natives.SameValue(1, obj1));
+assertFalse(natives.SameValue(1, undefined));
+assertFalse(natives.SameValue(1, NaN));
+assertFalse(natives.SameValue(1, "foo"));
+
+// Special string cases.
+assertFalse(natives.SameValue("1", 1));
+assertFalse(natives.SameValue("true", true));
+assertFalse(natives.SameValue("false", false));
+assertFalse(natives.SameValue("undefined", undefined));
+assertFalse(natives.SameValue("NaN", NaN));
+
+// -0 and +0 are should be different
+assertFalse(natives.SameValue(+0, -0));
+assertFalse(natives.SameValue(-0, +0));