Re: [PATCH] perf: fix wrong DEBUG configuration

[Arnaldo Carvalho de Melo]

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, usong 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.

- Arnaldo
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