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Don't use StoreIC_ArrayLength on frozen arrays

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The code previously assumed that an array with fast properties must have
a writable length property. But Object.freeze() now exposes a way to make
length read-only without moving the object into slow mode. This patch
simply adds a !is_frozen check to the IC code. Any future optimizations
to attribute-setting on JSArrays will need to make similar accomodations.

R=danno
BUG=v8:2711,259548

Review URL: https://chromiumcodereview.appspot.com/19115002
Patch from Adam Klein <adamk@chromium.org>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15651 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
danno@chromium.org 2013-07-14 22:03:46 +00:00
parent 625a0e9759
commit c65f4f7f7b
2 changed files with 37 additions and 2 deletions
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6
src/ic.cc
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@ -1662,12 +1662,14 @@ MaybeObject* StoreIC::Store(State state,
// Use specialized code for setting the length of arrays with fast
// properties. Slow properties might indicate redefinition of the length
// property.
// property. Note that when redefined using Object.freeze, it's possible
// to have fast properties but a read-only length.
if (FLAG_use_ic &&
receiver->IsJSArray() &&
name->Equals(isolate()->heap()->length_string()) &&
Handle<JSArray>::cast(receiver)->AllowsSetElementsLength() &&
receiver->HasFastProperties()) {
receiver->HasFastProperties() &&
!receiver->map()->is_frozen()) {
Handle<Code> stub =
StoreArrayLengthStub(kind(), strict_mode).GetCode(isolate());
set_target(*stub);

33
test/mjsunit/regress/regress-2711.js Normal file
View File

@ -0,0 +1,33 @@
// 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.
// Test that frozen arrays don't let their length change
var a = Object.freeze([1]);
a.push(2);
assertEquals(1, a.length);
a.push(2);
assertEquals(1, a.length);