By definition, retired blocks do not have "dead" objects, or at least none that we know of yet until the next marking phase has been run over it. So, we should not be sweeping them (even for zombie mode).
Created attachment 230391 [details]
Comment on attachment 230391 [details]
Thanks. Landed in r167948: <http://trac.webkit.org/r167948>.
Why did you do this?
Does this fix a bug in zombie mode? Improve performance?
(In reply to comment #4)
> Why did you do this?
> Does this fix a bug in zombie mode? Improve performance?
This fixes a bug when running with zombie mode. This is needed because unlike the default sweeper that only sweeps after a full collection (which ensures there are no retired blocks during a sweep), the zombie sweep can happen with just an eden collection (and hence, retired blocks can exists, and we'll fail an assertion if we don't ignore them).