Re: [PATCH] ftrace: Build with CPPFLAGS to get -Qunused-arguments
From: Masahiro Yamada
Date: Wed Sep 19 2018 - 10:55:46 EST
2018-09-18 2:24 GMT+09:00 Nick Desaulniers <ndesaulniers@xxxxxxxxxx>:
> On Mon, Sep 17, 2018 at 12:38 AM Joel Stanley <joel@xxxxxxxxx> wrote:
>> When building to record the mcount locations the kernel uses
>> KBUILD_CFLAGS but not KBUILD_CPPFLAGS. This means it lacks
>> -Qunused-arguments when building with clang, resulting in a lot of
>> noisy warnings.
>> Signed-off-by: Joel Stanley <joel@xxxxxxxxx>
>> Not sure why -Qunused-arguments is in CPP instead of KBUILD_CFLAGS. We
>> could instead put it in KBUILD_CFLAGS, and not need this patch.
> The preprocessor has flags that can change the definitions of macros.
> So there might be unused flags there. I'm not a fan of covering up
> those warnings via -Qunused-arguments; the flags should be feature
> detected via cc-option and friends rather than always added then
> silenced if excessive. That hides flags that are long dead/unused.
> Thanks for this patch!
> Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
>> scripts/Makefile.build | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
Applied to linux-kbuild/fixes. Thanks!