Make gctwa O(n) instead of O(n^2)

[lars-t-hansen]

This is much faster and I think it's still correct. With 200000 dead symbols on the oblist it runs in 90ms instead of 40s on my MacBook Pro.

It's ugly that it writes the proplists of candidate symbols while it's running; to do better we would use a separate hash table.

[WillClinger]

Thank you, Lars. Later today, when I have more time, I will accept this pull request and then simplify it a bit.

[lars-t-hansen]

Thanks, Will. In retrospect it is unnecessary to make the cookie an object, this hammers on the write barrier constantly. #f would be good enough. I think I was trying to preserve the type invariant of the property list field. Maybe the code ought to be wrapped in call-without-interrupts too. On Jul 20, 2017 1:08 PM, "Will Clinger" <notifications@github.com> wrote: Thank you, Lars. Later today, when I have more time, I will accept this pull request and then simplify it a bit. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#811 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AEmYlsmNNmItu9kroE1GRYhMv40FcmWcks5sP7PFgaJpZM4OeYgm> .