<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head><meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>[210659] branches/safari-603-branch/Source/JavaScriptCore</title>
</head>
<body>
<style type="text/css"><!--
#msg dl.meta { border: 1px #006 solid; background: #369; padding: 6px; color: #fff; }
#msg dl.meta dt { float: left; width: 6em; font-weight: bold; }
#msg dt:after { content:':';}
#msg dl, #msg dt, #msg ul, #msg li, #header, #footer, #logmsg { font-family: verdana,arial,helvetica,sans-serif; font-size: 10pt; }
#msg dl a { font-weight: bold}
#msg dl a:link { color:#fc3; }
#msg dl a:active { color:#ff0; }
#msg dl a:visited { color:#cc6; }
h3 { font-family: verdana,arial,helvetica,sans-serif; font-size: 10pt; font-weight: bold; }
#msg pre { overflow: auto; background: #ffc; border: 1px #fa0 solid; padding: 6px; }
#logmsg { background: #ffc; border: 1px #fa0 solid; padding: 1em 1em 0 1em; }
#logmsg p, #logmsg pre, #logmsg blockquote { margin: 0 0 1em 0; }
#logmsg p, #logmsg li, #logmsg dt, #logmsg dd { line-height: 14pt; }
#logmsg h1, #logmsg h2, #logmsg h3, #logmsg h4, #logmsg h5, #logmsg h6 { margin: .5em 0; }
#logmsg h1:first-child, #logmsg h2:first-child, #logmsg h3:first-child, #logmsg h4:first-child, #logmsg h5:first-child, #logmsg h6:first-child { margin-top: 0; }
#logmsg ul, #logmsg ol { padding: 0; list-style-position: inside; margin: 0 0 0 1em; }
#logmsg ul { text-indent: -1em; padding-left: 1em; }#logmsg ol { text-indent: -1.5em; padding-left: 1.5em; }
#logmsg > ul, #logmsg > ol { margin: 0 0 1em 0; }
#logmsg pre { background: #eee; padding: 1em; }
#logmsg blockquote { border: 1px solid #fa0; border-left-width: 10px; padding: 1em 1em 0 1em; background: white;}
#logmsg dl { margin: 0; }
#logmsg dt { font-weight: bold; }
#logmsg dd { margin: 0; padding: 0 0 0.5em 0; }
#logmsg dd:before { content:'\00bb';}
#logmsg table { border-spacing: 0px; border-collapse: collapse; border-top: 4px solid #fa0; border-bottom: 1px solid #fa0; background: #fff; }
#logmsg table th { text-align: left; font-weight: normal; padding: 0.2em 0.5em; border-top: 1px dotted #fa0; }
#logmsg table td { text-align: right; border-top: 1px dotted #fa0; padding: 0.2em 0.5em; }
#logmsg table thead th { text-align: center; border-bottom: 1px solid #fa0; }
#logmsg table th.Corner { text-align: left; }
#logmsg hr { border: none 0; border-top: 2px dashed #fa0; height: 1px; }
#header, #footer { color: #fff; background: #636; border: 1px #300 solid; padding: 6px; }
#patch { width: 100%; }
#patch h4 {font-family: verdana,arial,helvetica,sans-serif;font-size:10pt;padding:8px;background:#369;color:#fff;margin:0;}
#patch .propset h4, #patch .binary h4 {margin:0;}
#patch pre {padding:0;line-height:1.2em;margin:0;}
#patch .diff {width:100%;background:#eee;padding: 0 0 10px 0;overflow:auto;}
#patch .propset .diff, #patch .binary .diff {padding:10px 0;}
#patch span {display:block;padding:0 10px;}
#patch .modfile, #patch .addfile, #patch .delfile, #patch .propset, #patch .binary, #patch .copfile {border:1px solid #ccc;margin:10px 0;}
#patch ins {background:#dfd;text-decoration:none;display:block;padding:0 10px;}
#patch del {background:#fdd;text-decoration:none;display:block;padding:0 10px;}
#patch .lines, .info {color:#888;background:#fff;}
--></style>
<div id="msg">
<dl class="meta">
<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/210659">210659</a></dd>
<dt>Author</dt> <dd>matthew_hanson@apple.com</dd>
<dt>Date</dt> <dd>2017-01-12 08:46:05 -0800 (Thu, 12 Jan 2017)</dd>
</dl>
<h3>Log Message</h3>
<pre>Merge <a href="http://trac.webkit.org/projects/webkit/changeset/210553">r210553</a>. rdar://problem/29941356</pre>
<h3>Modified Paths</h3>
<ul>
<li><a href="#branchessafari603branchSourceJavaScriptCoreChangeLog">branches/safari-603-branch/Source/JavaScriptCore/ChangeLog</a></li>
<li><a href="#branchessafari603branchSourceJavaScriptCoreheapDeferGCh">branches/safari-603-branch/Source/JavaScriptCore/heap/DeferGC.h</a></li>
<li><a href="#branchessafari603branchSourceJavaScriptCoreruntimeJSArraycpp">branches/safari-603-branch/Source/JavaScriptCore/runtime/JSArray.cpp</a></li>
<li><a href="#branchessafari603branchSourceJavaScriptCoreruntimeJSArrayh">branches/safari-603-branch/Source/JavaScriptCore/runtime/JSArray.h</a></li>
<li><a href="#branchessafari603branchSourceJavaScriptCoreruntimeJSObjectcpp">branches/safari-603-branch/Source/JavaScriptCore/runtime/JSObject.cpp</a></li>
</ul>
</div>
<div id="patch">
<h3>Diff</h3>
<a id="branchessafari603branchSourceJavaScriptCoreChangeLog"></a>
<div class="modfile"><h4>Modified: branches/safari-603-branch/Source/JavaScriptCore/ChangeLog (210658 => 210659)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-603-branch/Source/JavaScriptCore/ChangeLog 2017-01-12 16:46:02 UTC (rev 210658)
+++ branches/safari-603-branch/Source/JavaScriptCore/ChangeLog 2017-01-12 16:46:05 UTC (rev 210659)
</span><span class="lines">@@ -1,5 +1,41 @@
</span><span class="cx"> 2017-01-12 Matthew Hanson <matthew_hanson@apple.com>
</span><span class="cx">
</span><ins>+ Merge r210553. rdar://problem/29941356
+
+ 2017-01-09 Filip Pizlo <fpizlo@apple.com>
+
+ JSArray has some object scanning races
+ https://bugs.webkit.org/show_bug.cgi?id=166874
+
+ Reviewed by Mark Lam.
+
+ This fixes two separate bugs, both of which I detected by running
+ array-splice-contiguous.js in extreme anger:
+
+ 1) Some of the paths of shifting and unshifting were not grabbing the internal cell
+ lock. This was causing the array storage scan to crash, even though it was well
+ synchronized (the scan does hold the lock). The fix is just to hold the lock anywhere
+ that memmoves the innards of the butterfly.
+
+ 2) Out of line property scanning was synchronized using double collect snapshot. Array
+ storage scanning was synchronized using locks. But what if array storage
+ transformations messed up the out of line properties? It turns out that we actually
+ need to hoist the array storage scanner's locking up into the double collect
+ snapshot.
+
+ I don't know how to write a test that does any better of a job of catching this than
+ array-splice-contiguous.js.
+
+ * heap/DeferGC.h: Make DisallowGC usable even if NDEBUG.
+ * runtime/JSArray.cpp:
+ (JSC::JSArray::unshiftCountSlowCase):
+ (JSC::JSArray::shiftCountWithArrayStorage):
+ (JSC::JSArray::unshiftCountWithArrayStorage):
+ * runtime/JSObject.cpp:
+ (JSC::JSObject::visitButterflyImpl):
+
+2017-01-12 Matthew Hanson <matthew_hanson@apple.com>
+
</ins><span class="cx"> Merge r210530. rdar://problem/29909896
</span><span class="cx">
</span><span class="cx"> 2017-01-09 Filip Pizlo <fpizlo@apple.com>
</span></span></pre></div>
<a id="branchessafari603branchSourceJavaScriptCoreheapDeferGCh"></a>
<div class="modfile"><h4>Modified: branches/safari-603-branch/Source/JavaScriptCore/heap/DeferGC.h (210658 => 210659)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-603-branch/Source/JavaScriptCore/heap/DeferGC.h 2017-01-12 16:46:02 UTC (rev 210658)
+++ branches/safari-603-branch/Source/JavaScriptCore/heap/DeferGC.h 2017-01-12 16:46:05 UTC (rev 210659)
</span><span class="lines">@@ -1,5 +1,5 @@
</span><span class="cx"> /*
</span><del>- * Copyright (C) 2013 Apple Inc. All rights reserved.
</del><ins>+ * Copyright (C) 2013-2017 Apple Inc. All rights reserved.
</ins><span class="cx"> *
</span><span class="cx"> * Redistribution and use in source and binary forms, with or without
</span><span class="cx"> * modification, are permitted provided that the following conditions
</span><span class="lines">@@ -67,31 +67,41 @@
</span><span class="cx"> Heap& m_heap;
</span><span class="cx"> };
</span><span class="cx">
</span><del>-#ifndef NDEBUG
</del><span class="cx"> class DisallowGC {
</span><span class="cx"> WTF_MAKE_NONCOPYABLE(DisallowGC);
</span><span class="cx"> public:
</span><span class="cx"> DisallowGC()
</span><span class="cx"> {
</span><ins>+#ifndef NDEBUG
</ins><span class="cx"> WTF::threadSpecificSet(s_isGCDisallowedOnCurrentThread, reinterpret_cast<void*>(true));
</span><ins>+#endif
</ins><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> ~DisallowGC()
</span><span class="cx"> {
</span><ins>+#ifndef NDEBUG
</ins><span class="cx"> WTF::threadSpecificSet(s_isGCDisallowedOnCurrentThread, reinterpret_cast<void*>(false));
</span><ins>+#endif
</ins><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> static bool isGCDisallowedOnCurrentThread()
</span><span class="cx"> {
</span><ins>+#ifndef NDEBUG
</ins><span class="cx"> return !!WTF::threadSpecificGet(s_isGCDisallowedOnCurrentThread);
</span><ins>+#else
+ return false;
+#endif
</ins><span class="cx"> }
</span><span class="cx"> static void initialize()
</span><span class="cx"> {
</span><ins>+#ifndef NDEBUG
</ins><span class="cx"> WTF::threadSpecificKeyCreate(&s_isGCDisallowedOnCurrentThread, 0);
</span><ins>+#endif
</ins><span class="cx"> }
</span><span class="cx">
</span><ins>+#ifndef NDEBUG
</ins><span class="cx"> JS_EXPORT_PRIVATE static WTF::ThreadSpecificKey s_isGCDisallowedOnCurrentThread;
</span><ins>+#endif
</ins><span class="cx"> };
</span><del>-#endif // NDEBUG
</del><span class="cx">
</span><span class="cx"> } // namespace JSC
</span></span></pre></div>
<a id="branchessafari603branchSourceJavaScriptCoreruntimeJSArraycpp"></a>
<div class="modfile"><h4>Modified: branches/safari-603-branch/Source/JavaScriptCore/runtime/JSArray.cpp (210658 => 210659)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-603-branch/Source/JavaScriptCore/runtime/JSArray.cpp 2017-01-12 16:46:02 UTC (rev 210658)
+++ branches/safari-603-branch/Source/JavaScriptCore/runtime/JSArray.cpp 2017-01-12 16:46:05 UTC (rev 210659)
</span><span class="lines">@@ -1,6 +1,6 @@
</span><span class="cx"> /*
</span><span class="cx"> * Copyright (C) 1999-2000 Harri Porten (porten@kde.org)
</span><del>- * Copyright (C) 2003, 2007-2009, 2012-2013, 2015-2016 Apple Inc. All rights reserved.
</del><ins>+ * Copyright (C) 2003-2017 Apple Inc. All rights reserved.
</ins><span class="cx"> * Copyright (C) 2003 Peter Kelly (pmk@post.com)
</span><span class="cx"> * Copyright (C) 2006 Alexey Proskuryakov (ap@nypop.com)
</span><span class="cx"> *
</span><span class="lines">@@ -298,7 +298,7 @@
</span><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> // This method makes room in the vector, but leaves the new space for count slots uncleared.
</span><del>-bool JSArray::unshiftCountSlowCase(VM& vm, DeferGC&, bool addToFront, unsigned count)
</del><ins>+bool JSArray::unshiftCountSlowCase(const AbstractLocker&, VM& vm, DeferGC&, bool addToFront, unsigned count)
</ins><span class="cx"> {
</span><span class="cx"> ArrayStorage* storage = ensureArrayStorage(vm);
</span><span class="cx"> Butterfly* butterfly = storage->butterfly();
</span><span class="lines">@@ -892,6 +892,9 @@
</span><span class="cx"> if (startIndex >= vectorLength)
</span><span class="cx"> return true;
</span><span class="cx">
</span><ins>+ DisallowGC disallowGC;
+ auto locker = holdLock(*this);
+
</ins><span class="cx"> if (startIndex + count > vectorLength)
</span><span class="cx"> count = vectorLength - startIndex;
</span><span class="cx">
</span><span class="lines">@@ -930,7 +933,7 @@
</span><span class="cx"> // the start of the Butterfly, which needs to point at the first indexed property in the used
</span><span class="cx"> // portion of the vector.
</span><span class="cx"> Butterfly* butterfly = m_butterfly.get()->shift(structure(), count);
</span><del>- m_butterfly.setWithoutBarrier(butterfly);
</del><ins>+ setButterfly(vm, butterfly);
</ins><span class="cx"> storage = butterfly->arrayStorage();
</span><span class="cx"> storage->m_indexBias += count;
</span><span class="cx">
</span><span class="lines">@@ -1098,7 +1101,7 @@
</span><span class="cx"> setButterfly(vm, newButterfly);
</span><span class="cx"> } else if (!moveFront && vectorLength - length >= count)
</span><span class="cx"> storage = storage->butterfly()->arrayStorage();
</span><del>- else if (unshiftCountSlowCase(vm, deferGC, moveFront, count))
</del><ins>+ else if (unshiftCountSlowCase(locker, vm, deferGC, moveFront, count))
</ins><span class="cx"> storage = arrayStorage();
</span><span class="cx"> else {
</span><span class="cx"> throwOutOfMemoryError(exec, scope);
</span></span></pre></div>
<a id="branchessafari603branchSourceJavaScriptCoreruntimeJSArrayh"></a>
<div class="modfile"><h4>Modified: branches/safari-603-branch/Source/JavaScriptCore/runtime/JSArray.h (210658 => 210659)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-603-branch/Source/JavaScriptCore/runtime/JSArray.h 2017-01-12 16:46:02 UTC (rev 210658)
+++ branches/safari-603-branch/Source/JavaScriptCore/runtime/JSArray.h 2017-01-12 16:46:05 UTC (rev 210659)
</span><span class="lines">@@ -1,6 +1,6 @@
</span><span class="cx"> /*
</span><span class="cx"> * Copyright (C) 1999-2000 Harri Porten (porten@kde.org)
</span><del>- * Copyright (C) 2003, 2007, 2008, 2009, 2012, 2015-2016 Apple Inc. All rights reserved.
</del><ins>+ * Copyright (C) 2003-2017 Apple Inc. All rights reserved.
</ins><span class="cx"> *
</span><span class="cx"> * This library is free software; you can redistribute it and/or
</span><span class="cx"> * modify it under the terms of the GNU Lesser General Public
</span><span class="lines">@@ -177,7 +177,7 @@
</span><span class="cx">
</span><span class="cx"> bool unshiftCountWithAnyIndexingType(ExecState*, unsigned startIndex, unsigned count);
</span><span class="cx"> bool unshiftCountWithArrayStorage(ExecState*, unsigned startIndex, unsigned count, ArrayStorage*);
</span><del>- bool unshiftCountSlowCase(VM&, DeferGC&, bool, unsigned);
</del><ins>+ bool unshiftCountSlowCase(const AbstractLocker&, VM&, DeferGC&, bool, unsigned);
</ins><span class="cx">
</span><span class="cx"> bool setLengthWithArrayStorage(ExecState*, unsigned newLength, bool throwException, ArrayStorage*);
</span><span class="cx"> void setLengthWritable(ExecState*, bool writable);
</span></span></pre></div>
<a id="branchessafari603branchSourceJavaScriptCoreruntimeJSObjectcpp"></a>
<div class="modfile"><h4>Modified: branches/safari-603-branch/Source/JavaScriptCore/runtime/JSObject.cpp (210658 => 210659)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-603-branch/Source/JavaScriptCore/runtime/JSObject.cpp 2017-01-12 16:46:02 UTC (rev 210658)
+++ branches/safari-603-branch/Source/JavaScriptCore/runtime/JSObject.cpp 2017-01-12 16:46:05 UTC (rev 210659)
</span><span class="lines">@@ -383,6 +383,20 @@
</span><span class="cx"> return nullptr;
</span><span class="cx"> structure = vm.getStructure(structureID);
</span><span class="cx"> lastOffset = structure->lastOffset();
</span><ins>+ IndexingType indexingType = structure->indexingType();
+ Locker<JSCell> locker(NoLockingNecessary);
+ switch (indexingType) {
+ case ALL_CONTIGUOUS_INDEXING_TYPES:
+ case ALL_ARRAY_STORAGE_INDEXING_TYPES:
+ // We need to hold this lock to protect against changes to the innards of the butterfly
+ // that can happen when the butterfly is used for array storage. We conservatively
+ // assume that a contiguous butterfly may transform into an array storage one, though
+ // this is probably more conservative than necessary.
+ locker = Locker<JSCell>(*this);
+ break;
+ default:
+ break;
+ }
</ins><span class="cx"> WTF::loadLoadFence();
</span><span class="cx"> butterfly = this->butterfly();
</span><span class="cx"> if (!butterfly)
</span><span class="lines">@@ -395,27 +409,17 @@
</span><span class="cx">
</span><span class="cx"> markAuxiliaryAndVisitOutOfLineProperties(visitor, butterfly, structure, lastOffset);
</span><span class="cx">
</span><del>- IndexingType oldType = structure->indexingType();
- switch (oldType) {
</del><ins>+ ASSERT(indexingType == structure->indexingType());
+
+ switch (indexingType) {
</ins><span class="cx"> case ALL_CONTIGUOUS_INDEXING_TYPES:
</span><del>- case ALL_ARRAY_STORAGE_INDEXING_TYPES: {
- // This lock is here to protect Contiguous->ArrayStorage transitions, but we could make that
- // race work if we needed to.
- auto locker = holdLock(*this);
- IndexingType newType = this->indexingType();
- butterfly = this->butterfly();
- switch (newType) {
- case ALL_CONTIGUOUS_INDEXING_TYPES:
- visitor.appendValuesHidden(butterfly->contiguous().data(), butterfly->publicLength());
- break;
- default: // ALL_ARRAY_STORAGE_INDEXING_TYPES
- visitor.appendValuesHidden(butterfly->arrayStorage()->m_vector, butterfly->arrayStorage()->vectorLength());
- if (butterfly->arrayStorage()->m_sparseMap)
- visitor.append(butterfly->arrayStorage()->m_sparseMap);
- break;
- }
</del><ins>+ visitor.appendValuesHidden(butterfly->contiguous().data(), butterfly->publicLength());
</ins><span class="cx"> break;
</span><del>- }
</del><ins>+ case ALL_ARRAY_STORAGE_INDEXING_TYPES:
+ visitor.appendValuesHidden(butterfly->arrayStorage()->m_vector, butterfly->arrayStorage()->vectorLength());
+ if (butterfly->arrayStorage()->m_sparseMap)
+ visitor.append(butterfly->arrayStorage()->m_sparseMap);
+ break;
</ins><span class="cx"> default:
</span><span class="cx"> break;
</span><span class="cx"> }
</span></span></pre>
</div>
</div>
</body>
</html>