Messages in this thread | | | Date | Fri, 22 May 2015 09:02:50 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] perf: fix wrong DEBUG configuration |
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* Arnaldo Carvalho de Melo <acme@kernel.org> wrote:
> Em Wed, May 20, 2015 at 06:16:51PM +0200, Martin Liška escreveu: > > On 05/20/2015 04:55 PM, Ingo Molnar wrote: > > >* Arnaldo Carvalho de Melo <acme@kernel.org> 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
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