Proposal: Improving the LLVM backend by packaging it

[Austin Seipp]

On Sat, Nov 1, 2014 at 10:43 AM, Ben Gamari <bgamari.foss at gmail.com> wrote:
> Austin Seipp <austin at well-typed.com> writes:
>
>> 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'm certainly not opposed to this idea and there is precedent in this
> area set by the Rust folks. That being said, I suspect some
> distributions may care pretty deeply about being able to compile against
> their own LLVM packaging, especially if they are already shipping the
> same LLVM version as we require. It would be really nice to hear your
> thoughts on this, Joachim.

Yes, this is a worry of mine too.

> Do you envision that LLVM always be built alongside GHC when bringing up a new working tree?

No - on Tier 1 platforms, I suggest we always provide binary packages
for developers to grab. Those same binaries would be shipped with the
actual binary distributions we create.

On Tier 2 platforms, people may have to compile things, but we can
provide some guidelines (and perhaps utilities/scripts) to help manage
this.

> I suppose there will also be a "make fetch-llvm"
> rule to grab a compatible binary snapshot from an archive
> for bringing up builds on small machines (presumably these could be
> built at least for the first-tier platforms?)

Yes, something like that is what I envisioned (a make target or a shell script).

> Cheers,
>
> - Ben



-- 
Regards,

Austin Seipp, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com/