[bug#49569] [PATCH] gnu: Add make-single-arch-llvm procedure.

["Ludovic Courtès" <ludo@gnu.org>]

Efraim Flashner <efraim@flashner.co.il> skribis:

> On Mon, Jul 26, 2021 at 06:47:14PM +0200, Ludovic Courtès wrote:
>> Hi,
>> 
>> Efraim Flashner <efraim@flashner.co.il> skribis:
>> 
>> > * gnu/packages/llvm.scm (make-single-arch-llvm): New procedure.
>> > (llvm-native-12, llvm-native): New variables.
>> > ---
>> >
>> > Using this copy of llvm for packages like mesa will reduce the closure
>> > of those packages. I don't suppose it would work as well for compilers
>> > like rust which use LLVM for compiling and targeting different
>> > architectures.
>> >
>> > This drops the size of llvm-12 from 167M to 111M.
>> 
>> That’s less impressive than I would have thought.

[...]

> I think you're mostly shocked by the large numbers, it is a drop of 33%.
>
> It turns out that llvm-julia uses something similar to only target one
> arch, so the idea's there somewhere. We could probably add it in there
> too for dlang. Icecat/icedove/mozjs-78 should be OK to switch. And
> xf86-video-vmware already has mesa as an input and could likely use a
> special llvm-for-mesa version.

OK, maybe that’d be an improvement, and indeed, 33% is not negligible.

> I can look at mesa and see which libraries from llvm it links to and see
> about just building those. A first look shows 50 llvm libraries from
> mesa and about 150 from llvm@11, with the 4 libraries being
> libOSMesa  libvulkan_radeon  libxatracker  libXvMCnouveau

Makes sense.

Does Mesa require some special GPU compiler backend in addition to the
native backend?

Thanks,
Ludo’.