Re: git: 4c0dfd5959bd - main - arm: fail early on gcc builds

On Fri, May 17, 2024 at 09:14:46AM -0700, John Baldwin wrote:
> On 5/17/24 9:01 AM, Brooks Davis wrote:
> > The branch main has been updated by brooks:
> > 
> > URL: https://cgit.FreeBSD.org/src/commit/?id=4c0dfd5959bd499754e3fc9a7ce37c1d5ece31f7
> > 
> > commit 4c0dfd5959bd499754e3fc9a7ce37c1d5ece31f7
> > Author:     Brooks Davis <brooks@FreeBSD.org>
> > AuthorDate: 2024-05-17 15:47:22 +0000
> > Commit:     Brooks Davis <brooks@FreeBSD.org>
> > CommitDate: 2024-05-17 16:01:19 +0000
> > 
> >      arm: fail early on gcc builds
> >      Since at least 2022 (see https://reviews.freebsd.org/D36754), it has
> >      not been possible to build armv6/armv7 with gcc due to atomics macros
> >      gcc doesn't like.  Prevent developers doing due diligance from wasting
> >      time and CPU cycles on this combination as it just fails to build in
> >      libc.
> >      Reviewed by:    imp, andrew
> >      Differential Revision:  https://reviews.freebsd.org/D45193
> 
> As I said in the review, this is a weird change.  Only amd64 and i386 build
> with GCC.  You should blacklist all the others if you are going to blacklist
> any, not just 32-bit arm.  I hadn't blacklisted any to make it possible for
> other developers to work on it.  Also, the review in question is probably not
> the right fix, it's probably that we need to pass different CFLAGS to GCC for
> 32-bit arm.

I think I misunderstood your point in the review.  I've wasted days
trying to do the right thing to let me reapply 4510f2ca9170 (Make
WITHOUT_UNDEFINED_VERSION the default) only to find that it's secret
knowledge that gcc builds are broken except on x86.

IMO there's less than zero value in universe targets that don't work
unless they are clearly fenced.

I propose disabling all the others and adding a flag to ignore this
guard.

-- Brooks

P.S. I've got aarch64 building except for GOOGLETEST and BOOT which both
fail to link due to relocation complaints.