[Fwd: Proposal: Improving the LLVM backend by packaging it]

Sylvestre Ledru sylvestre at debian.org
Thu Oct 30 15:49:03 UTC 2014


Obviously, I don't really like code duplication on a project like LLVM.
Especially since it seems like a fork.

If upstream goes this way (and I agree that it is going to be hard for the Debian
maintainer of ghc to go against that), it is going to be hard for the maintainer,
especially if there is no plan to sync LLVM from time to time (if they do,
well, you should be quite fine, LLVM is not super hard to maintain and we
can always exchange info).

However, I think upstream (ghc) should try to work more closely with LLVM and find a better
way to collaborate. Having patches applied in LLVM itself is simple and usually

BTW, there are discussion on LLVM mailing list on this topic.

So, I am not going to give a green or red light. I don't think this is going
to affect my work... Mostly, it is going to affect yours.


On 25/10/2014 11:23, Joachim Breitner wrote:
> Dear LLVM-Packaging-Team, Dear FTP-Masters,
> I’m maintaining the GHC package. GHC is the main Haskell compiler, and
> supports compiling via LLVM’s IR. For reasons well outlined at
> https://ghc.haskell.org/trac/ghc/wiki/ImprovedLLVMBackend
> they consider it impractical to support any arbitrary version of LLVM
> out there, as LLVM guarantees no stability in the IR code, and plan to
> bundle LLVM with GHC, possible with GHC-specific changes.
> They explicit want to hear our opinion on this, knowing about our
> avoid-code-copy-policy. Given the technicalities around it, I think they
> have a point and I don’t see what Debian could do different here, once
> upstream decides to go this way.
> Do you agree and can I give them a green light on this change?
> Greetings,
> Joachim
> -------- Weitergeleitete Nachricht --------
> Von: Austin Seipp <austin at well-typed.com>
> An: ghc-devs at haskell.org <ghc-devs at haskell.org>
> Kopie: Joachim Breitner <mail at joachim-breitner.de>, Nathan Howell
> <nathan.d.howell at gmail.com>, Reid Barton <rwbarton at gmail.com>, Ben
> Gamari <bgamari.foss at gmail.com>
> Betreff: Proposal: Improving the LLVM backend by packaging it
> Datum: Fri, 24 Oct 2014 18:52:53 -0500
> X-spam-score: -6.6 (------)
> Hi *,
> A few days ago a discussion on IRC occurred about the LLVM backend,
> its current status, and what we could do to make it a rock solid part
> of GHC for all our users.
> Needless to say, the situation right now isn't so hot: we have no
> commitment to version support, two major versions are busted, others
> are seriously buggy, and yet there are lots of things we could improve
> on.
> So I give you a proposal, from a few of us to you all, about improving it:
> https://ghc.haskell.org/trac/ghc/wiki/ImprovedLLVMBackend
> I won't repeat what's on the wiki page too much, but the TL;DR version
> is: we should start packaging a version of LLVM, and shipping it with
> e.g. binary distributions of GHC. It's just a lot better for everyone.
> I know we're normally fairly hesitant about things like this (shipping
> external dependencies), but I think it's the only sane thing to do
> here, and the situation is fairly unique in that it's not actually
> very complicated to implement or support, I think.
> We'd like to do this for 7.12. I've also wrangled some people to help.
> Those people know who they are (because they're CC'd), and I will now
> badger them into submission until it is fixed for 7.12.
> Please let me know what you think.
> PS. Joachim, I would be particularly interested in upstream needs for
> Debian, as I know of their standard packaging policy to not duplicate
> things.
> _______________________________________________
> Pkg-llvm-team mailing list
> Pkg-llvm-team at lists.alioth.debian.org
> http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/pkg-llvm-team

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