<!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>[171571] branches/safari-600.1-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/171571">171571</a></dd>
<dt>Author</dt> <dd>lforschler@apple.com</dd>
<dt>Date</dt> <dd>2014-07-24 18:12:26 -0700 (Thu, 24 Jul 2014)</dd>
</dl>
<h3>Log Message</h3>
<pre>Merged <a href="http://trac.webkit.org/projects/webkit/changeset/171564">r171564</a>. <rdar://problem/17757800></pre>
<h3>Modified Paths</h3>
<ul>
<li><a href="#branchessafari6001branchSourceJavaScriptCoreAPIJSWrapperMapmm">branches/safari-600.1-branch/Source/JavaScriptCore/API/JSWrapperMap.mm</a></li>
<li><a href="#branchessafari6001branchSourceJavaScriptCoreChangeLog">branches/safari-600.1-branch/Source/JavaScriptCore/ChangeLog</a></li>
</ul>
</div>
<div id="patch">
<h3>Diff</h3>
<a id="branchessafari6001branchSourceJavaScriptCoreAPIJSWrapperMapmm"></a>
<div class="modfile"><h4>Modified: branches/safari-600.1-branch/Source/JavaScriptCore/API/JSWrapperMap.mm (171570 => 171571)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-600.1-branch/Source/JavaScriptCore/API/JSWrapperMap.mm 2014-07-25 01:11:24 UTC (rev 171570)
+++ branches/safari-600.1-branch/Source/JavaScriptCore/API/JSWrapperMap.mm 2014-07-25 01:12:26 UTC (rev 171571)
</span><span class="lines">@@ -464,6 +464,11 @@
</span><span class="cx"> m_prototype = toJS(JSValueToObject(cContext, valueInternalValue(prototype), 0));
</span><span class="cx"> }
</span><span class="cx"> } else {
</span><ins>+ // We need to hold a reference to the superclass prototype here on the stack
+ // to that it won't get GC'ed while we do allocations between now and when we
+ // set it in this class' prototype below.
+ JSC::JSObject* superClassPrototype = superClassInfo->m_prototype.get();
+
</ins><span class="cx"> const char* className = class_getName(m_class);
</span><span class="cx">
</span><span class="cx"> // Create or grab the prototype/constructor pair.
</span><span class="lines">@@ -493,13 +498,15 @@
</span><span class="cx"> });
</span><span class="cx">
</span><span class="cx"> // Set [Prototype].
</span><del>- JSObjectSetPrototype([m_context JSGlobalContextRef], toRef(m_prototype.get()), toRef(superClassInfo->m_prototype.get()));
</del><ins>+ JSObjectSetPrototype([m_context JSGlobalContextRef], toRef(m_prototype.get()), toRef(superClassPrototype));
</ins><span class="cx"> }
</span><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> - (void)reallocateConstructorAndOrPrototype
</span><span class="cx"> {
</span><span class="cx"> [self allocateConstructorAndPrototypeWithSuperClassInfo:[m_context.wrapperMap classInfoForClass:class_getSuperclass(m_class)]];
</span><ins>+ // We should not add any code here that can trigger a GC or the prototype and
+ // constructor that we just created may be collected before they can be used.
</ins><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> - (JSValue *)wrapperForObject:(id)object
</span><span class="lines">@@ -519,9 +526,12 @@
</span><span class="cx"> if (!m_prototype)
</span><span class="cx"> [self reallocateConstructorAndOrPrototype];
</span><span class="cx"> ASSERT(!!m_prototype);
</span><ins>+ // We need to hold a reference to the prototype here on the stack to that it won't
+ // get GC'ed while we create the wrapper below.
+ JSC::JSObject* prototype = m_prototype.get();
</ins><span class="cx">
</span><span class="cx"> JSObjectRef wrapper = makeWrapper([m_context JSGlobalContextRef], m_classRef, object);
</span><del>- JSObjectSetPrototype([m_context JSGlobalContextRef], wrapper, toRef(m_prototype.get()));
</del><ins>+ JSObjectSetPrototype([m_context JSGlobalContextRef], wrapper, toRef(prototype));
</ins><span class="cx"> return [JSValue valueWithJSValueRef:wrapper inContext:m_context];
</span><span class="cx"> }
</span><span class="cx">
</span><span class="lines">@@ -530,6 +540,9 @@
</span><span class="cx"> if (!m_constructor)
</span><span class="cx"> [self reallocateConstructorAndOrPrototype];
</span><span class="cx"> ASSERT(!!m_constructor);
</span><ins>+ // If we need to add any code here in the future that can trigger a GC, we should
+ // cache the constructor pointer in a stack local var first so that it is protected
+ // from the GC until it gets used below.
</ins><span class="cx"> return [JSValue valueWithJSValueRef:toRef(m_constructor.get()) inContext:m_context];
</span><span class="cx"> }
</span><span class="cx">
</span></span></pre></div>
<a id="branchessafari6001branchSourceJavaScriptCoreChangeLog"></a>
<div class="modfile"><h4>Modified: branches/safari-600.1-branch/Source/JavaScriptCore/ChangeLog (171570 => 171571)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-600.1-branch/Source/JavaScriptCore/ChangeLog 2014-07-25 01:11:24 UTC (rev 171570)
+++ branches/safari-600.1-branch/Source/JavaScriptCore/ChangeLog 2014-07-25 01:12:26 UTC (rev 171571)
</span><span class="lines">@@ -1,5 +1,30 @@
</span><span class="cx"> 2014-07-24 Lucas Forschler <lforschler@apple.com>
</span><span class="cx">
</span><ins>+ Merge r171564
+
+ 2014-07-24 Mark Lam <mark.lam@apple.com>
+
+ JSWrapperMap's jsWrapperForObject() needs to keep weak prototype and constructors from being GCed.
+ <https://webkit.org/b/135258>
+
+ Reviewed by Mark Hahnenberg.
+
+ Where needed, we cache the prototype object pointer in a stack local var.
+ This allows it to be scanned by the GC, and hence be kept alive until
+ we use it. The constructor object will in turn be kept alive by the
+ prototype object.
+
+ Also added some comments to warn against future code additions that could
+ regress this issue.
+
+ * API/JSWrapperMap.mm:
+ (-[JSObjCClassInfo allocateConstructorAndPrototypeWithSuperClassInfo:]):
+ (-[JSObjCClassInfo reallocateConstructorAndOrPrototype]):
+ (-[JSObjCClassInfo wrapperForObject:]):
+ (-[JSObjCClassInfo constructor]):
+
+2014-07-24 Lucas Forschler <lforschler@apple.com>
+
</ins><span class="cx"> Merge r171558
</span><span class="cx">
</span><span class="cx"> 2014-07-24 Joseph Pecoraro <pecoraro@apple.com>
</span></span></pre>
</div>
</div>
</body>
</html>