[PATCH] Support/Unix: use lambda function to fix building errors with clang

[Mauro Rossi via llvm-commits]

Hi Hans,

Sorry, I support android-x86 project my skills as programmer are somehow limited
For more technical items, please check with Chih-Wei, who made the patch.

The patch commit message shows the error happening.

If it can help,  my github branch [0], which is building the only
commit requiring changes in the llvm codebase is the patch sumbitted
to llvm-commit (commit [1])
plus some minor reverts due to warnings treated as errors, all the
rest is building rules/sources lists.
BTW I am working on soong  building rules, which are more easy to maintain.

I would understand if you consider Android a non supported system and
we can live without having the patch in the llvm release_70 codebase
(it is one commit and the important thing is we can build, of course).

I am available for providing further build logs, even if I do not see
too much the point, but I may need instructions to do so.
Mauro

[0] https://github.com/maurossi/llvm/commits/oreo-x86_llvm70_release_70
[1] https://github.com/maurossi/llvm/commit/e15165b1c28562d50c36b592347b55afb101308c
Il giorno lun 27 ago 2018 alle ore 14:09 Hans Wennborg
<hans at chromium.org> ha scritto:
>
> I tried building Path.cpp using Clang built from r300080, but was
> unable to reproduce the problem.
>
> I suppose the declaration of ::open must be different than on my system.
>
> Can you send a preprocessed source file and compiler invocation that
> shows the error?
>
> On Mon, Aug 27, 2018 at 12:25 PM, Mauro Rossi <issor.oruam at gmail.com> wrote:
> > Re-added Pavel, Chih-We and llvm-commits ML,
> > which had erronously omitted in my previous message
> >
> > Mauro
> >
> > Il giorno lun 27 ago 2018 alle ore 12:22 Mauro Rossi
> > <issor.oruam at gmail.com> ha scritto:
> >>
> >> Hi Hans,
> >> thanks for your response
> >>
> >> Il giorno lun 27 ago 2018 alle ore 10:35 Hans Wennborg
> >> <hans at chromium.org> ha scritto:
> >> >
> >> > On Sat, Aug 25, 2018 at 1:22 PM, Mauro Rossi <issor.oruam at gmail.com> wrote:
> >> > > Hi Pavel,
> >> > >
> >> > > Il giorno mar 17 lug 2018 alle ore 08:36 Mauro Rossi
> >> > > <issor.oruam at gmail.com> ha scritto:
> >> > >>
> >> > >> Hi Pavel,
> >> > >>
> >> > >> Il giorno lun 16 lug 2018 alle ore 19:14 Pavel Labath <labath at google.com> ha scritto:
> >> > >>>
> >> > >>> I think all/most systems have open(2) defined as a variadic (...)
> >> > >>> function, so that can't be the only reason why this is failing for
> >> > >>> you. There must be something more which is specific to your platform.
> >> > >>> Nevertheless, the workaround is not bad, so there's no harm in
> >> > >>>
> >> > >>> changing this. Some people would even prefer the lambda based syntax.
> >> > >>
> >> > >>
> >> > >> We are using basically the same Build System/compilers of AOSP,
> >> > >> it seam that just using clang can produce the error because of behavior different from gcc.
> >> > >> In some comments in the web behaviors of gcc and clang were described as different.
> >> > >>
> >> > >> If you are also using clang, are you using the clang version with AOSP (8.1.0_r33 at the time of reporting)
> >> > >> I propose to check in order to identify root cause, then evaluate how to proceed.
> >> > >>
> >> > >> Mauro
> >> > >
> >> > > The building error is happening using default AOSP 8.1.0_r41 clang tool chain
> >> >
> >> > Can you print the "clang --version" output of that toolchain? If we
> >> > fix this, it would be good to put a comment about what compiler was
> >> > having a problem.
> >>
> >> As seen from build log this is the clang version (also used by AOSP,
> >> if I'm not wrong):
> >>
> >> maurossi at ANDROIDDEV:~/oreo-x86_kernel$
> >> prebuilts/clang/host/linux-x86/clang-4053586/bin/clang --version
> >> Android clang version 5.0.300080  (based on LLVM 5.0.300080)
> >> Target: x86_64-unknown-linux
> >> Thread model: posix
> >> InstalledDir: /home/maurossi/oreo-x86_kernel/prebuilts/clang/host/linux-x86/clang-4053586/bin
> >>
> >>
> >> >
> >> > > If you don't see drawbacks, would it be possible to queue the patch
> >> > > that solves the building problem
> >> > > as candidate for llvm 7.0rc3?
> >> > > This would prevent building issues for AOSP current and future Android releases
> >> > >
> >> > > After your feedback, I am adding Hans Wennborg to evaluate if the
> >> > > patch is an acceptable candidate for llvm 7.0rc3
> >> >
> >> > I'm OK with this, but the patch would have to land soon.
> >>
> >> The patch was sent on llvm-commits mailing list on July, 8th 2018,
> >> it can be applied in current release_70 branch as cherry-pick is working for me:
> >>
> >> http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20180702/567254.html
> >>
> >> Could you please modify the final commit message with clang version
> >> information provided?
> >> Thanks
> >>
> >> Kind regards
> >> Mauro
> >>
> >>
> >>
> >>
> >> >
> >> > Thanks,
> >> > Hans