Optimize Object.seal and Object.preventExtensions

test/mjsunit/object-prevent-extensions.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.
 
 // Tests the Object.preventExtensions method - ES 15.2.3.10
 
+// Flags: --allow-natives-syntax
+
 
 var obj1 = {};
 // Extensible defaults to true.
 assertTrue(Object.isExtensible(obj1));
 Object.preventExtensions(obj1);
 
 // Make sure the is_extensible flag is set.
 assertFalse(Object.isExtensible(obj1));
 obj1.x = 42;
 assertEquals(undefined, obj1.x);
@@ skipping 79 matching lines @@
 // assignment should return right hand side value
 var o = Object.preventExtensions({});
 var v = o.v = 50;
 assertEquals(undefined, o.v);
 assertEquals(50, v);
 
 // test same behavior as above, but for integer properties
 var n = o[0] = 100;
 assertEquals(undefined, o[0]);
 assertEquals(100, n);
+
+// Fast properties should remain fast
+obj = { x: 42, y: 'foo' };
+assertTrue(%HasFastProperties(obj));
+Object.preventExtensions(obj);
+assertFalse(Object.isExtensible(obj));
+assertFalse(Object.isSealed(obj));
+assertTrue(%HasFastProperties(obj));
+
+// Non-extensible objects should share maps where possible
+obj = { prop1: 1, prop2: 2 };
+obj2 = { prop1: 3, prop2: 4 };
+assertTrue(%HaveSameMap(obj, obj2));
+Object.preventExtensions(obj);
+Object.preventExtensions(obj2);
+assertFalse(Object.isExtensible(obj));
+assertFalse(Object.isExtensible(obj2));
+assertFalse(Object.isSealed(obj));
+assertFalse(Object.isSealed(obj2));
+assertTrue(%HaveSameMap(obj, obj2));
+
+// Non-extensible objects should share maps even when they have elements
+obj = { prop1: 1, prop2: 2, 75: 'foo' };
+obj2 = { prop1: 3, prop2: 4, 150: 'bar' };
+assertTrue(%HaveSameMap(obj, obj2));
+Object.preventExtensions(obj);
+Object.preventExtensions(obj2);
+assertFalse(Object.isExtensible(obj));
+assertFalse(Object.isExtensible(obj2));
+assertFalse(Object.isSealed(obj));
+assertFalse(Object.isSealed(obj2));
+assertTrue(%HaveSameMap(obj, obj2));