Re: Proposal: Improving the LLVM backend by packaging it

On Sat, Nov 1, 2014 at 10:43 AM, Ben Gamari wrote:

Austin Seipp 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/