[llvm-dev] [RFC] FileCheck: (dis)allowing unused prefixes

James Henderson via llvm-dev
2020-11-06T10:22:42Z

I think it would make more sense to add it at each individual call site.
This ensures that all cases are fixed, rather than just one in a file. It
also ensures that in the (hopefully unlikely) event that there are both
intentional and unintentional use-cases within a file, each one gets
checked.

On Thu, 5 Nov 2020 at 20:29, Mircea Trofin via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

> Thanks!
>
> On Thu, Nov 5, 2020 at 11:50 AM Fāng-ruì Sòng <maskray at google.com>
wrote:
>
>> On Thu, Nov 5, 2020 at 11:36 AM David Blaikie via llvm-dev
>> <llvm-dev at lists.llvm.org> wrote:
>> >
>> >
>> >
>> > On Thu, Nov 5, 2020 at 10:46 AM Mircea Trofin <mtrofin at
google.com>
>> wrote:
>> >>
>> >>
>> >>
>> >> On Thu, Nov 5, 2020 at 10:40 AM David Blaikie <dblaikie at
gmail.com>
>> wrote:
>> >>>
>> >>>
>> >>>
>> >>> On Thu, Nov 5, 2020 at 7:30 AM Mircea Trofin via llvm-dev
<
>> llvm-dev at lists.llvm.org> wrote:
>> >>>>
>> >>>> There are currently 1350 owner-less failures in the
spreadsheet.
>> These seem to be the larger areas there.
>> >>>>
>> >>>> If you see an area you have ownership or expertise in,
please sign
>> up for fixing the tests by Monday, Nov. 9.
>> >>>>
>> >>>> Otherwise, I will "blanket-add"
--allow-unused-prefixes=true to the
>> remaining failing tests.
>> >>>
>> >>>
>> >>> If/when you do that, probably worth adding a comment at
each site to
>> clarify that this was added automatically, not vetted/intentionally
added
>> by a human. Something like "// FIXME: Verify that unused prefixes
are used
>> intentionally" or the like.
>> >>
>> >> Ack. or, we can grep for -allow-unused-prefixes=true, wdyt?
>> >
>> >
>> > Not sure I understand who/when
<https://teams.googleplex.com/u/when>
>> they would grep for that?
>>
>
> AAh! Nevermind me :) forgot that there are reasonable cases using it. Yes,
> it makes sense to add a FIXME, perhaps at the start of each file
>
>
>> >
>> > I was suggesting adding an explicit "this use of
>> --allow-unused-prefixes=true hasn't been confirmed as
intentional" so that
>> the backwards compatibility cases can be distinguished from the
intentional
>> cases when someone is reading the test case, rather than puzzling over
why
>> this flag was added (which looks intentional) though the unused prefix
may
>> not make sense in that particular test. It'll make it easier in the
future
>> when someone does look at the test for them to not feel like
they're being
>> implicitly told "this use of unused prefixes is intentional"
(by the
>> presence of an explicit flag requesting such support) while staring at
the
>> test and not being able to see why someone would've done that
intentionally.
>>
>> Directly CCing some folks who can fix or find people to fix some
>> directories (*/AMDGPU, */X86, */OpenMP, */AArch64) on
>>
>>
https://docs.google.com/spreadsheets/d/1o6q3XH1n3DDyyccnYZ_kVfhFbTDzC_S09e973_cwYuw/edit#gid=0
>> After these big directories are cleaned up, the remaining tests should
>> be manageable in amount.
>>
>> How to reproduce:
>>
>> sed -i '/allow-unused-prefixes/s/true/false/'
>> llvm/utils/FileCheck/FileCheck.cpp
>> git update-index --assume-unchanged llvm/utils/FileCheck/FileCheck.cpp
>> ninja check-llvm   # or check-clang ...
>>
>>
>>
>>
>> >>>
>> >>>
>> >>>>
>> >>>>
>> >>>>
>> >>>> On Fri, Oct 30, 2020 at 12:48 PM Mircea Trofin
<mtrofin at google.com>
>> wrote:
>> >>>>>
>> >>>>> An update: as of 871d658c9ceb, the flag is now
available, if folks
>> need to use it.
>> >>>>>
>> >>>>> On Thu, Oct 29, 2020 at 10:28 AM Mircea Trofin
<mtrofin at google.com>
>> wrote:
>> >>>>>>
>> >>>>>> Hello all,
>> >>>>>>
>> >>>>>> TL;DR; if you used FileCheck --check-prefixes
and you missed
>> (misspelled, for instance) one of the prefixes in your test, FileCheck
>> silently ignores that and the test passes.
>> >>>>>>
>> >>>>>> 1579 tests have this property.
>> >>>>>>
>> >>>>>>
>> >>>>>> The details
>> >>>>>> ========>> >>>>>>
Please refer to https://reviews.llvm.org/D90281 and the
>> discussion there for more details (make sure you open "older
changes" for
>> full context)
>> >>>>>>
>> >>>>>> The problem is covered by the TL;DR;.
>> >>>>>>
>> >>>>>> The proposal is to add an explicit flag to
FileCheck,
>> --allow-unused-prefixes, to indicate whether the current behavior is
>> intended (for instance, jdoerfert contributed a scenario where that is
the
>> case).
>> >>>>>>
>> >>>>>> We want the default behavior to be
'strict', i.e.
>> --allow-unused-prefixes=false. Doing that right now would lead to 1500
test
>> failures.
>> >>>>>>
>> >>>>>> To get there (thanks, maskray, for
suggestion), we propose we:
>> >>>>>> * land D90281 where the flag is introduced,
but is flipped to
>> match today's behavior
>> >>>>>> * employ a 'busy beavers' approach,
where test maintainers patch
>> their tests:
>> >>>>>>   - either leveraging the flag, to explicitly
indicate that unused
>> prefixes is intended (i.e. add --allow-unused-patches=true); or
>> >>>>>>   - fix the test (e.g. maybe there was a
misspelling
>> issue/omission/etc).
>> >>>>>>
>> >>>>>> A spreadsheet with the failing tests is
available here [1].
>> >>>>>>
>> >>>>>> The request to the community members is to
please sign up for
>> their respective area in the spreadsheet, and then mark it completed
when
>> that's the case (yes/no in the respective column).
>> >>>>>>
>> >>>>>> When all the tests are fixed, we will then
flip
>> --allow-unused-prefixes to false by default.
>> >>>>>>
>> >>>>>> Meanwhile, please consider leveraging the flag
explicitly when you
>> author new tests that use --check-prefixes. That can be then cleaned up
>> easily after we switch to the 'strict' behavior.
>> >>>>>>
>> >>>>>> Thanks!
>> >>>>>>
>> >>>>>> [1]
>>
https://docs.google.com/spreadsheets/d/1o6q3XH1n3DDyyccnYZ_kVfhFbTDzC_S09e973_cwYuw/edit?usp=sharing
>> >>>>
>> >>>> _______________________________________________
>> >>>> LLVM Developers mailing list
>> >>>> llvm-dev at lists.llvm.org
>> >>>>
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>> >
>> > _______________________________________________
>> > LLVM Developers mailing list
>> > llvm-dev at lists.llvm.org
>> > https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
>>
>>
>> --
>> 宋方睿
>>
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