llvm dev - Mar 2016 - New buildbot with -Werror

Greetings,

I would like to propose adding a buildbot which builds with -Werror. The
reason for a new buildbot in this configuration is twofold:

1. It helps users who track and release from ToT, because they (generally)
seem to build with -Werror. Speaking from experience :-), new warnings tend
to crop up in a large range of commits, and end up blocking one or more of
these downstream users. These users also seem to span several
organizations, which makes coordination difficult.

1a. The current buildbots do not build with -Werror so that they will run
tests even if warnings are generated. It may or may not be reasonable to
enable -Werror by default for buildbots at some point in the future, but I
don't think it's quite reasonable to do so yet (judging based on the
rate
at which new warnings seem to get added, that would leave too many
buildbots broken). Adding a buildbot in the -Werror configuration should
help to inform any such future changes.

2. It helps users who develop without -Werror (either by conscious choice
or by oversight). Commits which inadvertently add warnings often seem to
get reverted; however, if a buildbot can deliver warnings quickly, the
committer can submit a small fix right away.

I have uploaded a diff to Phabricator, however I ask to please keep
high-level comments on this thread:
http://reviews.llvm.org/D18382

This build would be owned and monitored by Google.

If there are no strong objections in the next few days, I will go ahead
with this plan.

Thanks,
dlj
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Could we change the buildbot config to treat
warnings-as-errors-that-continue in the build step? (so we get the benefit
of further execution tests, while still sending fail-mail, etc for the
warning?)

On Tue, Mar 22, 2016 at 5:00 PM, David Jones via cfe-dev <
cfe-dev at lists.llvm.org> wrote:
> Greetings,
>
> I would like to propose adding a buildbot which builds with -Werror. The
> reason for a new buildbot in this configuration is twofold:
>
> 1. It helps users who track and release from ToT, because they (generally)
> seem to build with -Werror. Speaking from experience :-), new warnings tend
> to crop up in a large range of commits, and end up blocking one or more of
> these downstream users. These users also seem to span several
> organizations, which makes coordination difficult.
>
> 1a. The current buildbots do not build with -Werror so that they will run
> tests even if warnings are generated. It may or may not be reasonable to
> enable -Werror by default for buildbots at some point in the future, but I
> don't think it's quite reasonable to do so yet (judging based on
the rate
> at which new warnings seem to get added, that would leave too many
> buildbots broken). Adding a buildbot in the -Werror configuration should
> help to inform any such future changes.
>
> 2. It helps users who develop without -Werror (either by conscious choice
> or by oversight). Commits which inadvertently add warnings often seem to
> get reverted; however, if a buildbot can deliver warnings quickly, the
> committer can submit a small fix right away.
>
> I have uploaded a diff to Phabricator, however I ask to please keep
> high-level comments on this thread:
> http://reviews.llvm.org/D18382
>
> This build would be owned and monitored by Google.
>
> If there are no strong objections in the next few days, I will go ahead
> with this plan.
>
> Thanks,
> dlj
>
>
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>
>
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----- Original Message -----
> From: "David Jones via cfe-dev" <cfe-dev at lists.llvm.org>
> To: cfe-dev at lists.llvm.org, llvm-dev at lists.llvm.org
> Cc: gkistanova at gmail.com
> Sent: Tuesday, March 22, 2016 7:00:28 PM
> Subject: [cfe-dev] New buildbot with -Werror
> 
> Greetings,
> 
> 
> I would like to propose adding a buildbot which builds with -Werror.
> The reason for a new buildbot in this configuration is twofold:
> 
> 
> 1. It helps users who track and release from ToT, because they
> (generally) seem to build with -Werror. Speaking from experience
> :-), new warnings tend to crop up in a large range of commits, and
> end up blocking one or more of these downstream users. These users
> also seem to span several organizations, which makes coordination
> difficult.
> 
> 
> 1a. The current buildbots do not build with -Werror so that they will
> run tests even if warnings are generated. It may or may not be
> reasonable to enable -Werror by default for buildbots at some point
> in the future, but I don't think it's quite reasonable to do so yet
> (judging based on the rate at which new warnings seem to get added,
> that would leave too many buildbots broken). Adding a buildbot in
> the -Werror configuration should help to inform any such future
> changes.
> 
> 
> 2. It helps users who develop without -Werror (either by conscious
> choice or by oversight). Commits which inadvertently add warnings
> often seem to get reverted; however, if a buildbot can deliver
> warnings quickly, the committer can submit a small fix right away.
> 
> 
> I have uploaded a diff to Phabricator, however I ask to please keep
> high-level comments on this thread:
> http://reviews.llvm.org/D18382
> 
> 
> 
> This build would be owned and monitored by Google.
> 
> 
> If there are no strong objections in the next few days, I will go
> ahead with this plan.
> 
I think having -Werror bots is a good idea, at least when self hosting.
Non-self-hosting -Werror (i.e. with older versions of Clang, or with GCC, etc.)
might also be useful, but I'm less sure (since we can't fix those
warnings if the warning is the problem).

 -Hal
> 
> Thanks,
> dlj
> 
> 
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
> 
-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory

My thought was that its reasonable to expect no warnings when building from
bootstrap (as you say) and the last release of Clang. Generally, I think we
should work around warnings in the last release of Clang if only for the
convenience of folks using that release to build stage1 and using Werror.

Certainly, we tend to fix warnings even from earlier Clang versions and
from GCC in order to keep Werror clean.

On Tue, Mar 22, 2016 at 5:06 PM Hal Finkel via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> ----- Original Message -----
> > From: "David Jones via cfe-dev" <cfe-dev at
lists.llvm.org>
> > To: cfe-dev at lists.llvm.org, llvm-dev at lists.llvm.org
> > Cc: gkistanova at gmail.com
> > Sent: Tuesday, March 22, 2016 7:00:28 PM
> > Subject: [cfe-dev] New buildbot with -Werror
> >
> > Greetings,
> >
> >
> > I would like to propose adding a buildbot which builds with -Werror.
> > The reason for a new buildbot in this configuration is twofold:
> >
> >
> > 1. It helps users who track and release from ToT, because they
> > (generally) seem to build with -Werror. Speaking from experience
> > :-), new warnings tend to crop up in a large range of commits, and
> > end up blocking one or more of these downstream users. These users
> > also seem to span several organizations, which makes coordination
> > difficult.
> >
> >
> > 1a. The current buildbots do not build with -Werror so that they will
> > run tests even if warnings are generated. It may or may not be
> > reasonable to enable -Werror by default for buildbots at some point
> > in the future, but I don't think it's quite reasonable to do
so yet
> > (judging based on the rate at which new warnings seem to get added,
> > that would leave too many buildbots broken). Adding a buildbot in
> > the -Werror configuration should help to inform any such future
> > changes.
> >
> >
> > 2. It helps users who develop without -Werror (either by conscious
> > choice or by oversight). Commits which inadvertently add warnings
> > often seem to get reverted; however, if a buildbot can deliver
> > warnings quickly, the committer can submit a small fix right away.
> >
> >
> > I have uploaded a diff to Phabricator, however I ask to please keep
> > high-level comments on this thread:
> > http://reviews.llvm.org/D18382
> >
> >
> >
> > This build would be owned and monitored by Google.
> >
> >
> > If there are no strong objections in the next few days, I will go
> > ahead with this plan.
> >
>
> I think having -Werror bots is a good idea, at least when self hosting.
> Non-self-hosting -Werror (i.e. with older versions of Clang, or with GCC,
> etc.) might also be useful, but I'm less sure (since we can't fix
those
> warnings if the warning is the problem).
>
>  -Hal
>
> >
> > Thanks,
> > dlj
> >
> >
> > _______________________________________________
> > cfe-dev mailing list
> > cfe-dev at lists.llvm.org
> > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
> >
>
> --
> Hal Finkel
> Assistant Computational Scientist
> Leadership Computing Facility
> Argonne National Laboratory
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
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Yeah - tend to prefer self-host, or maybe at most "the prior release of
clang" if we want to be able to get these results quickly (faster than
rebuilding the compiler, etc)

On Tue, Mar 22, 2016 at 5:06 PM, Hal Finkel via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> ----- Original Message -----
> > From: "David Jones via cfe-dev" <cfe-dev at
lists.llvm.org>
> > To: cfe-dev at lists.llvm.org, llvm-dev at lists.llvm.org
> > Cc: gkistanova at gmail.com
> > Sent: Tuesday, March 22, 2016 7:00:28 PM
> > Subject: [cfe-dev] New buildbot with -Werror
> >
> > Greetings,
> >
> >
> > I would like to propose adding a buildbot which builds with -Werror.
> > The reason for a new buildbot in this configuration is twofold:
> >
> >
> > 1. It helps users who track and release from ToT, because they
> > (generally) seem to build with -Werror. Speaking from experience
> > :-), new warnings tend to crop up in a large range of commits, and
> > end up blocking one or more of these downstream users. These users
> > also seem to span several organizations, which makes coordination
> > difficult.
> >
> >
> > 1a. The current buildbots do not build with -Werror so that they will
> > run tests even if warnings are generated. It may or may not be
> > reasonable to enable -Werror by default for buildbots at some point
> > in the future, but I don't think it's quite reasonable to do
so yet
> > (judging based on the rate at which new warnings seem to get added,
> > that would leave too many buildbots broken). Adding a buildbot in
> > the -Werror configuration should help to inform any such future
> > changes.
> >
> >
> > 2. It helps users who develop without -Werror (either by conscious
> > choice or by oversight). Commits which inadvertently add warnings
> > often seem to get reverted; however, if a buildbot can deliver
> > warnings quickly, the committer can submit a small fix right away.
> >
> >
> > I have uploaded a diff to Phabricator, however I ask to please keep
> > high-level comments on this thread:
> > http://reviews.llvm.org/D18382
> >
> >
> >
> > This build would be owned and monitored by Google.
> >
> >
> > If there are no strong objections in the next few days, I will go
> > ahead with this plan.
> >
>
> I think having -Werror bots is a good idea, at least when self hosting.
> Non-self-hosting -Werror (i.e. with older versions of Clang, or with GCC,
> etc.) might also be useful, but I'm less sure (since we can't fix
those
> warnings if the warning is the problem).
>
>  -Hal
>
> >
> > Thanks,
> > dlj
> >
> >
> > _______________________________________________
> > cfe-dev mailing list
> > cfe-dev at lists.llvm.org
> > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
> >
>
> --
> Hal Finkel
> Assistant Computational Scientist
> Leadership Computing Facility
> Argonne National Laboratory
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
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On Tue, Mar 22, 2016 at 5:03 PM, David Blaikie <dblaikie at gmail.com>
wrote:
> Could we change the buildbot config to treat
> warnings-as-errors-that-continue in the build step? (so we get the benefit
> of further execution tests, while still sending fail-mail, etc for the
> warning?)
>
>
That sounds reasonable, although the buildbot implementation seems to be
pretty focused on make:
https://github.com/buildbot/buildbot/blob/master/master/buildbot/steps/shell.py#L374
I'm guessing that between CMake and Ninja, buildbot will probably need some
minor changes.

> On Tue, Mar 22, 2016 at 5:00 PM, David Jones via cfe-dev <
> cfe-dev at lists.llvm.org> wrote:
>
>> Greetings,
>>
>> I would like to propose adding a buildbot which builds with -Werror.
The
>> reason for a new buildbot in this configuration is twofold:
>>
>> 1. It helps users who track and release from ToT, because they
>> (generally) seem to build with -Werror. Speaking from experience :-),
new
>> warnings tend to crop up in a large range of commits, and end up
blocking
>> one or more of these downstream users. These users also seem to span
>> several organizations, which makes coordination difficult.
>>
>> 1a. The current buildbots do not build with -Werror so that they will
run
>> tests even if warnings are generated. It may or may not be reasonable
to
>> enable -Werror by default for buildbots at some point in the future,
but I
>> don't think it's quite reasonable to do so yet (judging based
on the rate
>> at which new warnings seem to get added, that would leave too many
>> buildbots broken). Adding a buildbot in the -Werror configuration
should
>> help to inform any such future changes.
>>
>> 2. It helps users who develop without -Werror (either by conscious
choice
>> or by oversight). Commits which inadvertently add warnings often seem
to
>> get reverted; however, if a buildbot can deliver warnings quickly, the
>> committer can submit a small fix right away.
>>
>> I have uploaded a diff to Phabricator, however I ask to please keep
>> high-level comments on this thread:
>> http://reviews.llvm.org/D18382
>>
>> This build would be owned and monitored by Google.
>>
>> If there are no strong objections in the next few days, I will go ahead
>> with this plan.
>>
>> Thanks,
>> dlj
>>
>>
>> _______________________________________________
>> cfe-dev mailing list
>> cfe-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>>
>>
>
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