source: webkit/trunk/JavaScriptCore/runtime/StructureChain.h@ 43383

Last change on this file since 43383 was 41232, checked in by [email protected], 16 years ago

JavaScriptCore:

2009-02-25 Geoffrey Garen <[email protected]>

Reviewed by Maciej Stachowiak.


Fixed <rdar://problem/6611174> REGRESSION (r36701): Unable to select
messages on hotmail (24052)


The bug was that for-in enumeration used a cached prototype chain without
validating that it was up-to-date.


This led me to refactor prototype chain caching so it was easier to work
with and harder to get wrong.


After a bit of inlining, this patch is performance-neutral on SunSpider
and the v8 benchmarks.

  • interpreter/Interpreter.cpp: (JSC::Interpreter::tryCachePutByID): (JSC::Interpreter::tryCacheGetByID):
  • jit/JITStubs.cpp: (JSC::JITStubs::tryCachePutByID): (JSC::JITStubs::tryCacheGetByID): (JSC::JITStubs::cti_op_get_by_id_proto_list): Use the new refactored goodness. See lines beginning with "-" and smile.
  • runtime/JSGlobalObject.h: (JSC::Structure::prototypeForLookup): A shout out to const.
  • runtime/JSPropertyNameIterator.h: (JSC::JSPropertyNameIterator::next): We can use a pointer comparison to see if our cached structure chain is equal to the object's structure chain, since in the case of a cache hit, we share references to the same structure chain.
  • runtime/Operations.h: (JSC::countPrototypeChainEntriesAndCheckForProxies): Use the new refactored goodness.
  • runtime/PropertyNameArray.h: (JSC::PropertyNameArray::PropertyNameArray): (JSC::PropertyNameArray::setShouldCache): (JSC::PropertyNameArray::shouldCache): Renamed "cacheable" to "shouldCache" to communicate that the client is specifying a recommendation, not a capability.


  • runtime/Structure.cpp: (JSC::Structure::Structure): No need to initialize a RefPtr. (JSC::Structure::getEnumerablePropertyNames): Moved some code into helper functions.

(JSC::Structure::prototypeChain): New centralized accessor for a prototype
chain. Revalidates on every access, since the objects in the prototype
chain may have mutated.

(JSC::Structure::isValid): Helper function for revalidating a cached
prototype chain.

(JSC::Structure::getEnumerableNamesFromPropertyTable):
(JSC::Structure::getEnumerableNamesFromClassInfoTable): Factored out of
getEnumerablePropertyNames.

  • runtime/Structure.h:
  • runtime/StructureChain.cpp: (JSC::StructureChain::StructureChain):
  • runtime/StructureChain.h: (JSC::StructureChain::create): No need for structureChainsAreEqual, since we use pointer equality now. Refactored StructureChain to make a little more sense and eliminate special cases for null prototypes.

LayoutTests:

2009-02-24 Geoffrey Garen <[email protected]>

Reviewed by Maciej Stachowiak.


Added a test for <rdar://problem/6611174> REGRESSION (r36701): Unable to
select messages on hotmail (24052)

  • fast/js/for-in-cached-expected.txt: Added.
  • fast/js/for-in-cached.html: Added.
  • fast/js/resources/for-in-cached.js: Added. (forIn):
File size: 1.9 KB
Line 
1/*
2 * Copyright (C) 2008 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef StructureChain_h
27#define StructureChain_h
28
29#include <wtf/OwnArrayPtr.h>
30#include <wtf/PassRefPtr.h>
31#include <wtf/RefCounted.h>
32#include <wtf/RefPtr.h>
33
34namespace JSC {
35
36 class Structure;
37
38 class StructureChain : public RefCounted<StructureChain> {
39 public:
40 static PassRefPtr<StructureChain> create(Structure* head) { return adoptRef(new StructureChain(head)); }
41 RefPtr<Structure>* head() { return m_vector.get(); }
42
43 private:
44 StructureChain(Structure* head);
45
46 OwnArrayPtr<RefPtr<Structure> > m_vector;
47 };
48
49} // namespace JSC
50
51#endif // StructureChain_h
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