On 03/01/14 12:37, Simon Peyton-Jones wrote:
| I've been tinkering with ARM NCG idea for quite some time now, but
| honestly I've been always in doubts if it's the best way for GHC at all.
| I've thought that the plan was to kind of move out of NCG to LLVM based
| backends and I've though that although this plan may be kind of stuck
| now, it's still on the table.
I have not been following the ARM and LLVM threads very closely, but here's my
take:
* LLVM is (I hope) very much on the table. LLVM itself is a well-resourced
project,
and we can expect it to continue to exist. We should piggy-back on all the
hard work that is going into it.
* But using LLVM has some disadvantages.
a) it imposes a dependency on LLVM
b) it makes compilation slower
Correct
c) we play some efficiency tricks (notably "tables next to code") that
LLVM can't play (yet). I think.
Actually we have to generate tables-next-to-code from LLVM too, because
the LLVM and NCG backends must be compatible (you can choose to use LLVM
on a module-by-module basis using -fllvm). So tables-next-to-code is
currently done using a post-processing step on the asm generated by LLVM.
Cheers,
Simon
So GHC currently aims to have a built-in NCG for popular platforms, and to rely
on LLVM for more esoteric platforms and also for superior optimisation.
Is this still a sensible policy?
Maybe you can articulate your doubts on the ARM NCG?
Simon
| -----Original Message-----
| From: ghc-devs [mailto:[email protected]] On Behalf Of Karel
| Gardas
| Sent: 03 January 2014 11:24
| To: Jens Petersen
| Cc: [email protected]
| Subject: Re: ticket for adding ARM backend to NCG?
|
|
| Guys,
|
| I've been tinkering with ARM NCG idea for quite some time now, but
| honestly I've been always in doubts if it's the best way for GHC at all.
| I've thought that the plan was to kind of move out of NCG to LLVM based
| backends and I've though that although this plan may be kind of stuck
| now, it's still on the table.
|
| Yes, I know that GHC is volunteering effort so if someone comes and asks
| for an ARM NCG implementation merge it'll be probably done in some time,
| but I'm not sure if it's what's the most welcome at the end.
|
| Just some of my doubts about it...
|
| I would really appreciate some authoritative word about the topic from
| more involved GHC developers... I mean especially about NCG future...
|
| Thanks!
| Karel
|
| On 01/ 3/14 09:35 AM, Jens Petersen wrote:
| > On 3 January 2014 03:10, Corey O'Connor <[email protected]
| > <mailto:[email protected]>> wrote:
| >
| > My interest is just to get involved somehow in the NCG. Starting a
| > new backend seemed reasonable only because I couldn't break
| > something that didn't exist. ;-)
| >
| >
| > Well a big +1 from me for armv7 NCG.
| >
| >
| > _______________________________________________
| > ghc-devs mailing list
| > [email protected]
| > http://www.haskell.org/mailman/listinfo/ghc-devs
|
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