llvm dev - Oct 2020 - 32-bit Architectures no longer tested by any buildbots causing bitrot

While using a raspberry pi 4 for a project, I've discovered 2 recent
regressions caused by the assumption that the target would be 64-bit. In both
cases, the developers noted that they missed the error because none of the
buildbots had picked it up.

I was able to quickly confirm that both issues were related to the size of
pointer types by spooling up a Debian i686 iso and building clang on it.  Could
we add either an i686 or armhf buildbot to avoid this class of bug creeping into
the code base?

Thanks

-Luke

Buildbots are effectively crowdsourced - there's no central pool of
resources/machines for this at the moment. You can contribute buildbots by
bringing up your own machine and having it added as a worker for a
configuration of your choosing.

On Tue, Oct 20, 2020 at 4:25 PM Luke Benes via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> While using a raspberry pi 4 for a project, I've discovered 2 recent
> regressions caused by the assumption that the target would be 64-bit. In
> both cases, the developers noted that they missed the error because none of
> the buildbots had picked it up.
>
> I was able to quickly confirm that both issues were related to the size of
> pointer types by spooling up a Debian i686 iso and building clang on it.
> Could we add either an i686 or armhf buildbot to avoid this class of bug
> creeping into the code base?
>
> Thanks
>
> -Luke
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
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On Tue, Oct 20, 2020 at 7:25 PM Luke Benes via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> While using a raspberry pi 4 for a project, I've discovered 2 recent
> regressions caused by the assumption that the target would be 64-bit.
Is this an assumption that the target would be 64-bit, or an assumption
that the host would be 64-bit?
For the first of those, there may be a different approach than adding a
buildbot: Finding a way to remind developers to add LIT tests that use the
32-bit target.

> In both cases, the developers noted that they missed the error because
> none of the buildbots had picked it up.
>
> I was able to quickly confirm that both issues were related to the size of
> pointer types by spooling up a Debian i686 iso and building clang on it.
> Could we add either an i686 or armhf buildbot to avoid this class of bug
> creeping into the code base?
>
> Thanks
>
> -Luke
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
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Hello Luke!

On 10/17/20 6:27 PM, Luke Benes via llvm-dev wrote:
> While using a raspberry pi 4 for a project, I've discovered 2 recent
regressions caused
> by the assumption that the target would be 64-bit. In both cases, the
developers noted
> that they missed the error because none of the buildbots had picked it up. 
> 
> I was able to quickly confirm that both issues were related to the size of
pointer types
> by spooling up a Debian i686 iso and building clang on it.  Could we add
either an i686
> or armhf buildbot to avoid this class of bug creeping into the code base? 
I'm working to set up a build bot for the upcoming M68k target which is 32
bits. And while
I'm at it, I can also set up build bots for 32-bit MIPS, 32-bit PowerPC and
32-bit ARM.

We need these targets in Debian and openSUSE, so I'm happy to help with this
effort.

We also need the SPARC target and we have enough SPARC hardware idling and
waiting for
work, so that would be a perfect application as well.

I need to become familiar with the build bot setup first as I have not done this
before,
so if someone experienced with those bots is willing to assist me, that would be
great.

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz at debian.org
`. `'   Freie Universitaet Berlin - glaubitz at physik.fu-berlin.de
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

Hello everyone,

Just to save you some effort. There are a quite a few Arm buildbots including
armhf running on http://lab.llvm.org:8011/#/builders maintained by Linaro. For
example: clang-cmake-armv7-full . More bots are always welcome though
particularly if they are checking a different configuration.

I think there has been some buildbot maintenance recently, and the interface has
completely changed since I last looked. There is a possibility that they missed
this particular issue, or it was ignored which can happen if the failure
isn't reproducible locally on a non Arm machine. If the bots aren't
running properly will be worth pinging the maintainer.

Peter



________________________________________
From: llvm-dev <llvm-dev-bounces at lists.llvm.org> on behalf of John Paul
Adrian Glaubitz via llvm-dev <llvm-dev at lists.llvm.org>
Sent: 21 October 2020 08:06
To: Luke Benes
Cc: llvm-dev at lists.llvm.org; Joseph Huber
Subject: Re: [llvm-dev] 32-bit Architectures no longer tested by any buildbots
causing bitrot

Hello Luke!

On 10/17/20 6:27 PM, Luke Benes via llvm-dev wrote:
> While using a raspberry pi 4 for a project, I've discovered 2 recent
regressions caused
> by the assumption that the target would be 64-bit. In both cases, the
developers noted
> that they missed the error because none of the buildbots had picked it up.
>
> I was able to quickly confirm that both issues were related to the size of
pointer types
> by spooling up a Debian i686 iso and building clang on it.  Could we add
either an i686
> or armhf buildbot to avoid this class of bug creeping into the code base?
I'm working to set up a build bot for the upcoming M68k target which is 32
bits. And while
I'm at it, I can also set up build bots for 32-bit MIPS, 32-bit PowerPC and
32-bit ARM.

We need these targets in Debian and openSUSE, so I'm happy to help with this
effort.

We also need the SPARC target and we have enough SPARC hardware idling and
waiting for
work, so that would be a perfect application as well.

I need to become familiar with the build bot setup first as I have not done this
before,
so if someone experienced with those bots is willing to assist me, that would be
great.

Adrian

--
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz at debian.org
`. `'   Freie Universitaet Berlin - glaubitz at physik.fu-berlin.de
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

_______________________________________________
LLVM Developers mailing list
llvm-dev at lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev

Hi,

On Wed, 21 Oct 2020 at 01:25, Luke Benes via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
>
> While using a raspberry pi 4 for a project, I've discovered 2 recent
regressions caused by the assumption that the target would be 64-bit. In both
cases, the developers noted that they missed the error because none of the
buildbots had picked it up.
>
> I was able to quickly confirm that both issues were related to the size of
pointer types by spooling up a Debian i686 iso and building clang on it.  Could
we add either an i686 or armhf buildbot to avoid this class of bug creeping into
the code base?
Is this building *just* clang, without any other subprojects? That
would be very strange, since at least the armv7 bots should have
caught the regressions (unless they were already red when the
regressions were introduced, and then nobody got pinged). If the
regressions were in mlir, then that is expected, since we do not build
mlir on armv7 (or any other 32-bit platform, IIUC). I have asked if
there is interest for this and nobody said anything [1].

Cheers,
Diana

[1] https://llvm.discourse.group/t/mlir-on-armv7/1596
> Thanks
>
> -Luke
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev