[llvm-commits] RFC: LLVM incubation, or requirements for committing new backends

[Tom Stellard]

On Mon, Jul 16, 2012 at 01:21:18PM -0700, Eric Christopher wrote:
> 
> On Jul 16, 2012, at 1:17 PM, Tom Stellard <thomas.stellard at amd.com> wrote:
> 
> > I am in favor of this.  I think having specific criteria and time lines
> > will be beneficial for both maintainers and reviewers.
> > 
> > However, instead of having a separate branch, what do you think about
> > adding the backend to the main tree, but not building it by default.
> > This would make it easier for the backend maintainer to keep it up to date
> > and also make it easier for users to test it.  At the same time, the
> > backend maintainer would still be responsible for updating it for changes
> > to the LLVM core API, so other developers wouldn't need to worry about
> > breaking the "backend-in-training".
> 
> Actually a branch is a better idea for a couple of reasons:
> 
> 1) It'll help show that you're dedicated to the idea of maintaining the target, and
> 2) If the overhead of merging is too high for the target there are probably patches
> that need to be either a) upstreamed or b) the target needs to be rewritten since it
> shouldn't affect the main code base.
> 
> The part about other users is a good idea, but how often are users (not developers)
> checking out a copy of random ToT llvm in order to use it?
>

This is very common for users of the Mesa Project[1], which the R600/SI
backend is currently a part of.  Also some distributions package the
current TOT of various projects to offer users an easy way to try out the latest code.

-Tom

[1] http://www.mesa3d.org