From: Arnd Bergmann <arnd@arndb.de>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: Andrew Lunn <andrew@lunn.ch>,
Nick Desaulniers <ndesaulniers@google.com>,
netdev <netdev@vger.kernel.org>,
David Miller <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Michal Marek <michal.lkml@markovi.net>,
Rohit Maheshwari <rohitm@chelsio.com>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH net-next v2 1/2] Makefile.extrawarn: Add symbol for W=1 warnings for today
Date: Mon, 12 Oct 2020 10:11:53 +0200 [thread overview]
Message-ID: <CAK8P3a2LxR7BXhMktQN-Q-JpYq0ziMZVPHhu47k3CQ9OuKWUTg@mail.gmail.com> (raw)
In-Reply-To: <CAK7LNASB6ashOzmL5XntkPSq9a+8VoWCowP5CAt+oX0o=0y=dA@mail.gmail.com>
On Sun, Oct 11, 2020 at 3:04 PM Masahiro Yamada <masahiroy@kernel.org> wrote:
> On Tue, Oct 6, 2020 at 6:08 AM Andrew Lunn <andrew@lunn.ch> wrote:
>
>
> I am not a big fan of KBUILD_CFLAGS_W1_<timestamp>
> since it is ugly.
>
> I'd like to start with adding individual flags
> like drivers/gpu/drm/i915/Makefile, and see
> how difficult it would be to maintain it.
I don't really like that either, to be honest, mostly because that is
somewhat incompatible with my plan to move all the warning flags
out the command line and into _Pragma() lines in header files.
> One drawback of your approach is that
> you cannot set KBUILD_CFLAGS_W1_20200930
> until you eliminate all the warnings in the
> sub-directory in interest.
> (i.e. all or nothing approach)
>
> At best, you can only work out from 'old -> new' order
> because KBUILD_CFLAGS_W1_20200326 is a suer-set of
> KBUILD_CFLAGS_W1_20190907, which is a suer-set of
> KBUILD_CFLAGS_W1_20190617 ...
>
>
>
> If you add flags individually, you can start with
> low-hanging fruits, or ones with higher priority
> as Arnd mentions about -Wmissing-{declaration,prototypes}.
>
>
> For example, you might be able to set
> 'subdir-ccflags-y += -Wmissing-declarations'
> to drivers/net/Makefile, while
> 'subdir-ccflags-y += -Wunused-but-set-variable'
> stays in drivers/net/ethernet/Makefile.
I agree with the goal though. In particular it may be helpful to pick
a set of warning flags to always be enabled without also setting
-Wextra, which has different meanings depending on compiler
version, or between gcc and clang.
I wonder how different they really are, and we can probably find
out from https://github.com/Barro/compiler-warnings, but I have
not checked myself.
Arnd
next prev parent reply other threads:[~2020-10-12 8:12 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-01 1:12 [RFC PATCH net-next v2 0/2] driver/net/ethernet W=1 by default Andrew Lunn
2020-10-01 1:12 ` [PATCH net-next v2 1/2] Makefile.extrawarn: Add symbol for W=1 warnings for today Andrew Lunn
2020-10-01 23:09 ` Nick Desaulniers
2020-10-02 1:44 ` Andrew Lunn
2020-10-02 12:20 ` Arnd Bergmann
2020-10-02 12:51 ` Andrew Lunn
2020-10-02 13:15 ` Arnd Bergmann
2020-10-12 1:00 ` Masahiro Yamada
2020-10-12 8:05 ` Arnd Bergmann
2020-10-05 17:31 ` Nick Desaulniers
2020-10-05 19:49 ` Andrew Lunn
2020-10-05 20:03 ` Arnd Bergmann
2020-10-05 21:08 ` Andrew Lunn
2020-10-11 13:03 ` Masahiro Yamada
2020-10-12 8:11 ` Arnd Bergmann [this message]
2020-10-16 14:12 ` Andrew Lunn
[not found] ` <CAK8P3a1nBhmf1PQwHHbEjiVgRTXi4UuJAbwuK92CKEbR=yKGWw@mail.gmail.com>
2020-10-17 14:57 ` Andrew Lunn
2020-10-02 11:08 ` kernel test robot
2020-10-01 1:12 ` [PATCH net-next v2 2/2] driver/net/ethernet: Sign up for W=1 as defined on 20200930 Andrew Lunn
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