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Date:   Mon, 31 Jul 2023 10:10:36 +0200
From:   Thomas =?utf-8?Q?Wei=C3=9Fschuh?= <linux@weissschuh.net>
To:     Zhangjin Wu <falcon@tinylab.org>
Cc:     linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
        shuah@kernel.org, tanyuan@tinylab.org, w@1wt.eu
Subject: Re: [PATCH 4/4] selftests/nolibc: enable -Wall compiler warnings
Message-ID: <940dcf77-05ae-4cf6-b5f0-5b8cf80adab6@t-8ch.de>
References: <20230731-nolibc-warnings-v1-4-74973d2a52d7@weissschuh.net>
 <20230731071718.21085-1-falcon@tinylab.org>
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On 2023-07-31 15:17:18+0800, Zhangjin Wu wrote:
> > It will help the developers to avoid cruft and detect some bugs.
> > 
> > Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
> > ---
> >  tools/testing/selftests/nolibc/Makefile | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
> > index f42adef87e12..72227d75c6da 100644
> > --- a/tools/testing/selftests/nolibc/Makefile
> > +++ b/tools/testing/selftests/nolibc/Makefile
> > @@ -79,7 +79,7 @@ endif
> >  CFLAGS_s390 = -m64
> >  CFLAGS_mips = -EL
> >  CFLAGS_STACKPROTECTOR ?= $(call cc-option,-mstack-protector-guard=global $(call cc-option,-fstack-protector-all))
> > -CFLAGS  ?= -Os -fno-ident -fno-asynchronous-unwind-tables -std=c89 \
> > +CFLAGS  ?= -Os -fno-ident -fno-asynchronous-unwind-tables -std=c89 -Wall \
> 
> Very good static analyzer support.
> 
> What about further add more options?
> 
>     +CFLAGS  ?= -Os -fno-ident -fno-asynchronous-unwind-tables -std=c89 -Wall -Wextra -Werror\
> 
> A simple test shows, it can catch more issues.

-Wextra will need some further rework for 32bit architectures to avoid
some warnings.
(At least mips for which I tested it)

I don't think -Werror is appropriate. If we want to test the functioning
of nolibc with weird compilers these may very well add new warnings and
that shouldn't break the build.

> 
> Thanks,
> Zhangjin
> 
> >  		$(call cc-option,-fno-stack-protector) \
> >  		$(CFLAGS_$(ARCH)) $(CFLAGS_STACKPROTECTOR)
> >  LDFLAGS := -s
> > 
> > -- 
> > 2.41.0