On October 7, 2020 2:02:53 PM EDT, David Feuer <david.fe...@gmail.com> wrote: >Yes, the bitmap structures used to encode the structure of stack >frames. These *look* like they might be reusable for mix-and-match >arrays in Haskell-land. If so, that could be a pretty cheap new >feature.
Ahh, yes. In principle we could expose a new array type allowing the user to specify the pointer-ness of each entry. This wouldn't reuse any of the large bitmap machinery since these must be specified in the info table rather than the closure but the idea is similar. Implementation would require a new set of primops along with GC support but I suspect that none of this is too hard. All these being said, this may not be terribly efficient for garbage collection since the GC will need to walk over both pointers and non-pointers, trashing a good amount of cache in the process. Moreover, the array itself would be larger, due to the two bitmaps. I suspect most applications would be on the whole better served by a structure of arrays approach to achieve the same idea. If you have multiple pointers and locality is a concern then you can even pack all of your pointers into a single array with some indexing magic and an unsafeCoerce. Cheers, - Ben _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
