v8/test/mjsunit/regress/readonly2.js
verwaest@chromium.org a8b3215afa Change LookupForWrite to always do a full lookup and check the result.
If we find a property in the prototype-chain that we can overwrite, and
we have a transition, keep the holder in the lookup-result as the actual
holder. We will need it for the consistency-check in GenerateStoreField.

By directly checking the entire chain we avoid having to lazily bail out
to a copy of the miss stub while generating the Field Store IC.

Currently this CL disallows a normal non-receiver holder, given that
that would require a positive lookup + details verification to ensure
the property did not become read-only. This fixes the regressions in the
attached tests.

Review URL: https://chromiumcodereview.appspot.com/12810006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14061 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-03-25 12:55:27 +00:00

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JavaScript

// Copyright 2013 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.
Object.defineProperty(this, "x", { writable:true });
function s(v) {
v.x = 1;
}
function s_strict(v) {
"use strict";
v.x = 1;
}
function c(p) {
return {__proto__: p};
}
var o1 = c(this);
var o2 = c(this);
// Initialize the store IC.
s(c(this));
s(c(this));
s_strict(c(this));
s_strict(c(this));
// Make x non-writable.
Object.defineProperty(this, "x", { writable:false, value:5 });
// Verify that direct setting fails.
o1.x = 20;
assertEquals(5, o1.x);
// Verify that setting through the IC fails.
s(o2);
assertEquals(5, o2.x);
assertThrows("s_strict(o2);", TypeError);