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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - Remove AllocationProfileWatchpoint node"
href="https://bugs.webkit.org/show_bug.cgi?id=143999#c3">Comment # 3</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - Remove AllocationProfileWatchpoint node"
href="https://bugs.webkit.org/show_bug.cgi?id=143999">bug 143999</a>
from <span class="vcard"><a class="email" href="mailto:fpizlo@apple.com" title="Filip Pizlo <fpizlo@apple.com>"> <span class="fn">Filip Pizlo</span></a>
</span></b>
<pre>Comment on <span class=""><a href="attachment.cgi?id=251246&action=diff" name="attach_251246" title="Tentative patch, non thread-safe">attachment 251246</a> <a href="attachment.cgi?id=251246&action=edit" title="Tentative patch, non thread-safe">[details]</a></span>
Tentative patch, non thread-safe
View in context: <a href="https://bugs.webkit.org/attachment.cgi?id=251246&action=review">https://bugs.webkit.org/attachment.cgi?id=251246&action=review</a>
<span class="quote">>> Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp:2643
>> if (Structure* structure = function->allocationStructure()) {
>
> We probably need to freeze the rare data here, in case it is removed by the JS thread and then the GC runs at that point.
> Not sure how to do this, I first need to investigate more deeply how freeze() & the GC works.</span >
It seems that you're using JSFunction's helpers to get things from the rare data. I would make this explicit here, so instead of function->allocationStructure() you'd do something like rareData->allocationStructure(). And instead of function->allocationProfileWatchpointSet() you'd do rareData->allocationProfileWatchpointSet().
Then you'd do:
FunctionRareData* rareData = function->rareData();
if (rareData) {
if (Structure* structure = rareData->structure()) {
m_graph.freeze(rareData);
m_graph.watchpoints().addLazily(rareData->allocationProfileWatchpointSet()); // note that here you don't have to do any null checking - you know that rareData has the InlineWatchpointSet in place rather than via pointer.
... the rest
}
}</pre>
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