[m-rev.] for review: Add support for weak pointers to the C RTS

[Peter Wang]

On Sat, 19 Jul 2014 11:45:33 +1000, Peter Wang <novalazy at gmail.com> wrote:
> 
> An alternative solution would be to allocate a bit array to mark off the
> elements that have been restored already, as you iterate forwards from
> the oldest update to the newest.  If the i'th bit is set then the i'th
> element of the version array was already restored to an older value, so
> just ignore the current update.  No prev pointers required.

You can also destructively reverse the list of ML_va nodes, then apply
the updates from newest to oldest.  For the case where you need the
original list you can reverse it again afterwards.

Peter