Re: [PATCH v1 6/6] perf build: Enable -Wthread-safety with clang

From: Ian Rogers <irogers@google.com>
To: Namhyung Kim <namhyung@kernel.org>
Cc: "Peter Zijlstra" <peterz@infradead.org>,
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	llvm@lists.linux.dev
Subject: Re: [PATCH v1 6/6] perf build: Enable -Wthread-safety with clang
Date: Thu, 18 Aug 2022 06:17:38 -0700	[thread overview]
Message-ID: <CAP-5=fVVV8UPppzet7jwvrf9ig8RpWE1x4mxAJBAnuqbdSbP-Q@mail.gmail.com> (raw)
In-Reply-To: <CAM9d7cgd-KsqJNxh_MbX9h4tr8rOtAqKe-t7Qfck0m9pTxWK7w@mail.gmail.com>

On Wed, Aug 17, 2022, 11:11 PM Namhyung Kim <namhyung@kernel.org> wrote:
>
> Hi Ian,
>
> On Tue, Aug 16, 2022 at 10:39 PM Ian Rogers <irogers@google.com> wrote:
> >
> > If building with clang then enable -Wthread-safety warnings.
>
> Do you know the minimal supported version for the option?
> I'm not sure we have a check for that kind of thing.

It has been supported for a long time, close to 10 years. Looking
around it looks like clang 3.5 had the support. For context, BPF was
supported after clang 3.7. Given this long support, and we don't
version check for BPF, I think it is okay to assume the flag is
supported.

Thanks,
Ian

>
> Thanks,
> Namhyung
>
>
> >
> > Signed-off-by: Ian Rogers <irogers@google.com>
> > ---
> >  tools/perf/Makefile.config | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> > index 0661a1cf9855..0ef6f572485d 100644
> > --- a/tools/perf/Makefile.config
> > +++ b/tools/perf/Makefile.config
> > @@ -19,6 +19,11 @@ detected_var = $(shell echo "$(1)=$($(1))" >> $(OUTPUT).config-detected)
> >  CFLAGS := $(EXTRA_CFLAGS) $(filter-out -Wnested-externs,$(EXTRA_WARNINGS))
> >  HOSTCFLAGS := $(filter-out -Wnested-externs,$(EXTRA_WARNINGS))
> >
> > +# Enabled Wthread-safety analysis for clang builds.
> > +ifeq ($(CC_NO_CLANG), 0)
> > +  CFLAGS += -Wthread-safety
> > +endif
> > +
> >  include $(srctree)/tools/scripts/Makefile.arch
> >
> >  $(call detected_var,SRCARCH)
> > --
> > 2.37.1.595.g718a3a8f04-goog
> >