Bug 162006

Summary: There is no good reason for WeakBlock to care about newly allocated objects
Product: WebKit Reporter: Filip Pizlo <fpizlo>
Component: JavaScriptCoreAssignee: Filip Pizlo <fpizlo>
Status: RESOLVED FIXED    
Severity: Normal CC: barraclough, benjamin, commit-queue, ggaren, jfbastien, keith_miller, mark.lam, mhahnenb, msaboff, oliver, saam, sam
Priority: P2    
Version: WebKit Nightly Build   
Hardware: All   
OS: All   
Bug Depends on:    
Bug Blocks: 149432    
Attachments:
Description Flags
possibly the patch fpizlo: review+

Filip Pizlo
Reported 2016-09-14 19:45:51 PDT
WeakBlock scans itself in two modes: visit: if a Weak in the block belongs to an unmarked object, ask the Weak to consider whether it should do things. reap: if a Weak in a block belongs to an unmarked object, delete the Weak. Except that "unmarked" has a peculiar meaning: WeakBlock defines it as !markedOrNewlyAllocated. So, a newly allocated object will never be consulted about anything. That sounds scary until you realize that newlyAllocated must have been cleared before we even got here. So, we were paying the price of checking newlyAllocated for no reason.
Attachments
possibly the patch (4.90 KB, patch)
2016-09-14 19:48 PDT, Filip Pizlo 		fpizlo: review+
DetailsFormatted DiffDiff
View All Add attachment proposed patch, testcase, etc.
Filip Pizlo
Comment 1 2016-09-14 19:48:35 PDT
Created attachment 288919 [details] possibly the patch
Filip Pizlo
Comment 2 2016-09-15 10:17:45 PDT
Comment on attachment 288919 [details] possibly the patch r=ggaren in person
Filip Pizlo
Comment 3 2016-09-15 10:19:32 PDT
Landed in https://trac.webkit.org/changeset/205979
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