Re: [PATCH] perf: fix wrong DEBUG configuration

[Martin LiÅka]

On 05/22/2015 09:02 AM, Ingo Molnar wrote:
> * Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> wrote:
>
> > Em Wed, May 20, 2015 at 06:16:51PM +0200, Martin LiÅka escreveu:
> > > On 05/20/2015 04:55 PM, Ingo Molnar wrote:
> > > > * Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> wrote:
> > > > > So the rule has been: What are the kernel requirements for the
> > > > > toolchain? tools/perf/ should build with that.
> > > >
> > > > So we could use -Og if it works, like Kbuild does it:
> > > >
> > > >          KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
> > > >
> > > > the 'cc-option' Make function does some magic of silently calling GCC
> > > > with that option and observing the result.
> >
> > > > See:
> >
> > > >    scripts/Kbuild.include:cc-option = $(call try-run,\
> >
> > > I am sorry, I did mistake in understanding of DEBUG variable.
> > > Following patch should be fixed, except missing auto-detection
> > > of -Og option.
> > >
> > > Unfortunately, following hunk does not work, no -Ox is added to CFLAGS?
> > >
> > > --  CFLAGS += -Og
> > > ++  CFLAGS += $(call cc-option,-Og,-O0)
> >
> > I don't know if we have this cc-option, perhaps Ingo is suggesting
> > we get it in tools/build/? Or include scripts/Kbuild.include and
> > then use it?
> >
> > I.e. we have checks to see if we can use, for instance
> > -fstack-protector-all, see tools/build/feature/Makefile, using this
> > cc-option thing, importing it from Kbuild would solve the issue at
> > hand in a definitive way and in line with what we have been
> > pursuing: to make the tools/ build system be based on Kbuild.
>
> So I'd suggest copying any necessary functions instead of outright
> including all of Kbuild in the tooling build system which creates
> non-trivial dependencies that is not necessarily tested as thoroughly
> on the kbuild side as on the tooling side.
>
> Thanks,
>
> 	Ingo

May I ask you Ingo for helping with that? It would be easy to test if you
grab my patch and add necessary bash functions.

Thank you,
Martin
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