Bug 213687

Summary:	findGCObjectPointersForMarking may have optimization opportunities
Product:	WebKit	Reporter:	Keith Miller <keith_miller>
Component:	JavaScriptCore	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Normal
Priority:	P2
Version:	WebKit Nightly Build
Hardware:	Unspecified
OS:	Unspecified

Description Keith Miller 2020-06-27 16:47:07 PDT

https://bugs.webkit.org/show_bug.cgi?id=213686 indicated it was a 2% perf regression on Speedo2 and JetStream2 to not return early from findGCObjectPointersForMarking after finding a live pointer to some HeapKind::JSCell. Likely, that regression comes from trying to determine if the pointer was live. It's possible most of this is from checking if the different pointers are live. 

Some improvements could be specializing findGCObjectPointersForMarking on the HeapKind or passing all values simultaneously to MarkedBlock::isLive.