Bug 65404 – JSC GC zombie support no longer works, and is likely no longer needed

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[Filip Pizlo]

The JSC GC has support for installing zombie cells in free memory as a way of tracking when a reference in the heap is missed.  But this functionality no longer works, and is not tested during any regressions (either in bots or in command-line tools).  It's not clear that it's needed, since WebCore and JSC appear to track references accurately enough to be correct.  Furthermore, it's not clear that the GC should continue to support a relatively complex piece of untested functionality, which makes implementing new features difficult, and whose existence is predicated upon the GC being broken.  In short, zombie support should be removed unless a good argument can be made for its necessity.

[Filip Pizlo]

Created attachment 102416 [details]
the patch

[Early Warning System Bot]

Comment on attachment 102416 [details]
the patch

Attachment 102416 [details] did not pass qt-ews (qt):
Output: http://queues.webkit.org/results/9267624

[Gyuyoung Kim]

Comment on attachment 102416 [details]
the patch

Attachment 102416 [details] did not pass efl-ews (efl):
Output: http://queues.webkit.org/results/9267623

[Filip Pizlo]

Created attachment 102419 [details]
the patch (fix various platforms)

[WebKit Review Bot]

Comment on attachment 102419 [details]
the patch (fix various platforms)

Clearing flags on attachment: 102419

Committed r92046: <http://trac.webkit.org/changeset/92046>

[WebKit Review Bot]

All reviewed patches have been landed.  Closing bug.

[Zoltan Herczeg]

Sad thing... was a nice feature.