RE: git: 58dba5b8212f - main - devel/llvm19: prune build on 32-bit archs

> Brooks Davis <brooks_at_freebsd.org> wrote on
> Date: Tue, 27 Aug 2024 21:19:02 UTC :
> 
> On Tue, Aug 27, 2024 at 07:23:37PM +0000, Brooks Davis wrote:
> > The branch main has been updated by brooks:
> > 
> > URL: https://cgit.FreeBSD.org/ports/commit/?id=58dba5b8212fd4dc77e07f58810ae959ae29fc6e
> > 
> > commit 58dba5b8212fd4dc77e07f58810ae959ae29fc6e
> > Author: Brooks Davis <brooks@FreeBSD.org>
> > AuthorDate: 2024-08-27 19:23:23 +0000
> > Commit: Brooks Davis <brooks@FreeBSD.org>
> > CommitDate: 2024-08-27 19:23:23 +0000
> > 
> > devel/llvm19: prune build on 32-bit archs
> > 
> > Given trends in compiler resource use, it is incresingly implausible to
> > consider cross-development from a 32-bit system. As such, stop spending
> > time building LLVM bits are are vinishingly unlikely to be used on
> > 32-bit systems.
> > 
> > Default to BE_NATIVE (no cross build support) on 32-bit plaforms.
> > Disable BE_AMDGPU and BE_WASM as well. BE_AMDGPU consumes enormous
> > amounts of memory. BE_WASM is less problematic, but no one has stood up
> > to say they need it so turn it off for now.
> > 
> > Completely disable MLIR and POLLY on 32-bit. Just building MLIR fails
> > routinly on armv7 and there aren't a lot of direct users (it's used by
> > FLANG, but FLANG is 64-bit only). Polly is pretty niche and adds quite
> > a bit of build time.
> 
> I'm looking for feedback on this change and plan to merge a version of it
> back to older LLVM ports after a suitable period. If you need something
> I've disabled in your use case, let me know.

Another thing that had some discussion was making the 32-bit ld.lld
default for threads behave like --threads=1 when not explicitly set.
This mostly avoids memory pressure and, also, the likes of having,
say, up to 16 threads active for 4 builders when there are 4 cores
if all 4 builders end up running ld.lld in parallel over a time.

Is there an intent to also do that? Are you looking for feedback on
that idea as well?

===
Mark Millard
marklmi at yahoo.com