From c65f4f7f7bbd64763c95144233f29b62661e798b Mon Sep 17 00:00:00 2001 From: "danno@chromium.org" Date: Sun, 14 Jul 2013 22:03:46 +0000 Subject: [PATCH] Don't use StoreIC_ArrayLength on frozen arrays 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 . git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15651 ce2b1a6d-e550-0410-aec6-3dcde31c8c00 --- src/ic.cc | 6 +++-- test/mjsunit/regress/regress-2711.js | 33 ++++++++++++++++++++++++++++ 2 files changed, 37 insertions(+), 2 deletions(-) create mode 100644 test/mjsunit/regress/regress-2711.js diff --git a/src/ic.cc b/src/ic.cc index a15863e141..f84b3b9248 100644 --- a/src/ic.cc +++ b/src/ic.cc @@ -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::cast(receiver)->AllowsSetElementsLength() && - receiver->HasFastProperties()) { + receiver->HasFastProperties() && + !receiver->map()->is_frozen()) { Handle stub = StoreArrayLengthStub(kind(), strict_mode).GetCode(isolate()); set_target(*stub); diff --git a/test/mjsunit/regress/regress-2711.js b/test/mjsunit/regress/regress-2711.js new file mode 100644 index 0000000000..a58e789745 --- /dev/null +++ b/test/mjsunit/regress/regress-2711.js @@ -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);