Sorry, I confused 'DynamicGhcPrograms' merely with 'DynamicGhc'. In other words: DynamicGhc means exactly what I said before - dynamic GHC, static everything else.
As for the reason why the switch wasn't made for x86, I was not privvy to the decision at the time, but I imagine it's one of consistency. To ship a x64 GHC with these features (where it was acceptable) but not a 32bit one means essentially you force 32bit users into one of two situations: - Your compiled program may not work in GHCi, or at all in some corner cases, and most of the bugs that were there are effectively unfixed. - Your compiled program suffers a noticeable performance hit, due to register theft. Which is rather unfortunate. On the other hand, if you dynamically link GHC only, only GHC itself pays a hit on the dynamic linking, and your remaining programs are unaffected. On Mon, Oct 20, 2014 at 9:32 AM, Jeremy <volderm...@hotmail.com> wrote: > Austin Seipp <austin <at> well-typed.com> writes: > >> As far as I'm aware, Dynamic-by-default GHC is actually broken, and I >> don't know for how long this has been the case. >> >> For some history: originally when all this was being decided to try >> and fix the linker issues in GHC, dynamic by default was considered an >> option, but was rejected in favor of DynamicGhcPrograms. Why was it >> rejected? Well, dynamic by default particularly hurts 32bit x86, which >> suffers from a very pathetic set of registers, and dynamic programs >> steal one of these for the GOT (%ebx IIRC). >> >> On the other hand, DynamicGhcPrograms instead means GHC builds >> everything statically, *except itself*, which it builds as a >> dynamically linked executable. The idea is you dynamically link GHC >> itself to fix linker issues, and end-user programs remain static, >> which is the expected mode of operation. > > Thank you for the detailed explanation (although I still don't understand > why DYNAMIC_BY_DEFAULT by default wasn't kept for x64.) > > Where does GhcDynamic fit into this? > > _______________________________________________ > Glasgow-haskell-users mailing list > Glasgow-haskell-users@haskell.org > http://www.haskell.org/mailman/listinfo/glasgow-haskell-users > -- Regards, Austin Seipp, Haskell Consultant Well-Typed LLP, http://www.well-typed.com/ _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
