Use map transitions when defining accessor properties.

test/mjsunit/accessor-map-sharing.js

Index: test/mjsunit/accessor-map-sharing.js
diff --git a/test/mjsunit/accessor-map-sharing.js b/test/mjsunit/accessor-map-sharing.js
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+// Copyright 2012 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: --allow-natives-syntax
+
+// Handy abbreviations.
+var dp = Object.defineProperty;
+var gop = Object.getOwnPropertyDescriptor;
+
+function getter() { return 111; }
+function setter(x) { print(222); }
+function anotherGetter() { return 333; }
+function anotherSetter(x) { print(444); }
+var obj1, obj2;
+
+// Two objects with the same getter.
+obj1 = {};
+dp(obj1, "alpha", { get: getter });
+obj2 = {};
+dp(obj2, "alpha", { get: getter });
+assertTrue(%HaveSameMap(obj1, obj2));
+
+// Two objects with the same getter, oldskool.
+obj1 = {};
+obj1.__defineGetter__("bravo", getter);
+assertEquals(getter, obj1.__lookupGetter__("bravo"));
+obj2 = {};
+obj2.__defineGetter__("bravo", getter);
+assertEquals(getter, obj2.__lookupGetter__("bravo"));
+assertTrue(%HaveSameMap(obj1, obj2));
+
+// Two objects with the same setter.
+obj1 = {};
+dp(obj1, "charlie", { set: setter });
+obj2 = {};
+dp(obj2, "charlie", { set: setter });
+assertTrue(%HaveSameMap(obj1, obj2));
+
+// Two objects with the same setter, oldskool.
+obj1 = {};
+obj1.__defineSetter__("delta", setter);
+assertEquals(setter, obj1.__lookupSetter__("delta"));
+obj2 = {};
+obj2.__defineSetter__("delta", setter);
+assertEquals(setter, obj2.__lookupSetter__("delta"));
+assertTrue(%HaveSameMap(obj1, obj2));
+
+// Two objects with the same getter and setter.
+obj1 = {};
+dp(obj1, "foxtrot", { get: getter, set: setter });
+obj2 = {};
+dp(obj2, "foxtrot", { get: getter, set: setter });
+assertTrue(%HaveSameMap(obj1, obj2));
+
+// Two objects with the same getter and setter, set separately.
+obj1 = {};
+dp(obj1, "golf", { get: getter, configurable: true });
+dp(obj1, "golf", { set: setter, configurable: true });
+obj2 = {};
+dp(obj2, "golf", { get: getter, configurable: true });
+dp(obj2, "golf", { set: setter, configurable: true });
+assertTrue(%HaveSameMap(obj1, obj2));
+
+// Two objects with the same getter and setter, set separately, oldskool.
+obj1 = {};
+obj1.__defineGetter__("hotel", getter);
+obj1.__defineSetter__("hotel", setter);
+obj2 = {};
+obj2.__defineGetter__("hotel", getter);
+obj2.__defineSetter__("hotel", setter);
+assertTrue(%HaveSameMap(obj1, obj2));
+
+// Attribute-only change, shouldn't affect previous descriptor properties.
+obj1 = {};
+dp(obj1, "india", { get: getter, configurable: true, enumerable: true });
+assertEquals(getter, gop(obj1, "india").get);
+assertTrue(gop(obj1, "india").configurable);
+assertTrue(gop(obj1, "india").enumerable);
+dp(obj1, "india", { enumerable: false });
+assertEquals(getter, gop(obj1, "india").get);
+assertTrue(gop(obj1, "india").configurable);
+assertFalse(gop(obj1, "india").enumerable);
+
+// Attribute-only change, shouldn't affect objects with previously shared maps.
+obj1 = {};
+dp(obj1, "juliet", { set: setter, configurable: true, enumerable: false });
+assertEquals(setter, gop(obj1, "juliet").set);
+assertTrue(gop(obj1, "juliet").configurable);
+assertFalse(gop(obj1, "juliet").enumerable);
+obj2 = {};
+dp(obj2, "juliet", { set: setter, configurable: true, enumerable: false });
+assertEquals(setter, gop(obj2, "juliet").set);
+assertTrue(gop(obj2, "juliet").configurable);
+assertFalse(gop(obj2, "juliet").enumerable);
+dp(obj1, "juliet", { set: setter, configurable: false, enumerable: true });
+assertEquals(setter, gop(obj1, "juliet").set);
+assertFalse(gop(obj1, "juliet").configurable);
+assertTrue(gop(obj1, "juliet").enumerable);
+assertEquals(setter, gop(obj2, "juliet").set);
+assertTrue(gop(obj2, "juliet").configurable);
+assertFalse(gop(obj2, "juliet").enumerable);
+
+// Two objects with the different getters.
+obj1 = {};
+dp(obj1, "kilo", { get: getter });
+obj2 = {};
+dp(obj2, "kilo", { get: anotherGetter });
+assertEquals(getter, gop(obj1, "kilo").get);
+assertEquals(anotherGetter, gop(obj2, "kilo").get);
+assertFalse(%HaveSameMap(obj1, obj2));
+
+// Two objects with the same getters and different setters.
+obj1 = {};
+dp(obj1, "lima", { get: getter, set: setter });
+obj2 = {};
+dp(obj2, "lima", { get: getter, set: anotherSetter });
+assertEquals(setter, gop(obj1, "lima").set);
+assertEquals(anotherSetter, gop(obj2, "lima").set);
+assertFalse(%HaveSameMap(obj1, obj2));
+
+// Even 'undefined' is a kind of getter.
+obj1 = {};
+dp(obj1, "mike", { get: undefined });
+assertTrue("mike" in obj1);
+assertEquals(undefined, gop(obj1, "mike").get);
+assertEquals(undefined, obj1.__lookupGetter__("mike"));
+assertEquals(undefined, gop(obj1, "mike").set);
+assertEquals(undefined, obj1.__lookupSetter__("mike"));
+
+// Even 'undefined' is a kind of setter.
+obj1 = {};
+dp(obj1, "november", { set: undefined });
+assertTrue("november" in obj1);
+assertEquals(undefined, gop(obj1, "november").get);
+assertEquals(undefined, obj1.__lookupGetter__("november"));
+assertEquals(undefined, gop(obj1, "november").set);
+assertEquals(undefined, obj1.__lookupSetter__("november"));
+
+// Redefining a data property.
+obj1 = {};
+obj1.oscar = 12345;
+dp(obj1, "oscar", { set: setter });
+assertEquals(setter, gop(obj1, "oscar").set);
+
+// Re-adding the same getter/attributes pair.
+obj1 = {};
+dp(obj1, "papa", { get: getter, configurable: true });
+dp(obj1, "papa", { get: getter, set: setter, configurable: true });
+assertEquals(getter, gop(obj1, "papa").get);
+assertEquals(setter, gop(obj1, "papa").set);
+assertTrue(gop(obj1, "papa").configurable);
+assertFalse(gop(obj1, "papa").enumerable);