linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Masahiro Yamada <yamada.masahiro@socionext.com>
To: Nathan Huckleberry <nhuck@google.com>
Cc: Michal Marek <michal.lkml@markovi.net>,
	Joe Perches <joe@perches.com>,
	Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
	Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	clang-built-linux <clang-built-linux@googlegroups.com>,
	Nathan Chancellor <natechancellor@gmail.com>
Subject: Re: [PATCH v2] kbuild: Require W=1 for -Wimplicit-fallthrough with clang
Date: Mon, 19 Aug 2019 01:43:08 +0900	[thread overview]
Message-ID: <CAK7LNATsA0foyeaE2W3xe=_Hkf9S=q0eD5WHqwPXkMw8udkDPg@mail.gmail.com> (raw)
In-Reply-To: <20190815225844.145726-1-nhuck@google.com>

Hi.

On Fri, Aug 16, 2019 at 7:59 AM Nathan Huckleberry <nhuck@google.com> wrote:
>
> Clang is updating to support -Wimplicit-fallthrough on C
> https://reviews.llvm.org/D64838. Since clang does not
> support the comment version of fallthrough annotations
> this update causes an additional 50k warnings. Most
> of these warnings (>49k) are duplicates from header files.
>
> This patch is intended to be reverted after the warnings
> have been cleaned up.
>
> Signed-off-by: Nathan Huckleberry <nhuck@google.com>
> Suggested-by: Nathan Chancellor <natechancellor@gmail.com>
> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
> Changes v1->v2
> * Move code to preexisting ifdef
>  scripts/Makefile.extrawarn | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
> index a74ce2e3c33e..95973a1ee999 100644
> --- a/scripts/Makefile.extrawarn
> +++ b/scripts/Makefile.extrawarn
> @@ -70,5 +70,6 @@ KBUILD_CFLAGS += -Wno-initializer-overrides
>  KBUILD_CFLAGS += -Wno-format
>  KBUILD_CFLAGS += -Wno-sign-compare
>  KBUILD_CFLAGS += -Wno-format-zero-length
> +KBUILD_CFLAGS += $(call cc-option,-Wno-implicit-fallthrough)
>  endif
>  endif
> --
> 2.23.0.rc1.153.gdeed80330f-goog
>


Perhaps, is the following even cleaner?



diff --git a/Makefile b/Makefile
index 1b23f95db176..cebc6bf5372e 100644
--- a/Makefile
+++ b/Makefile
@@ -751,6 +751,9 @@ else
 # These warnings generated too much noise in a regular build.
 # Use make W=1 to enable them (see scripts/Makefile.extrawarn)
 KBUILD_CFLAGS += -Wno-unused-but-set-variable
+
+# Warn about unmarked fall-throughs in switch statement.
+KBUILD_CFLAGS += $(call cc-option,-Wimplicit-fallthrough,)
 endif

 KBUILD_CFLAGS += $(call cc-disable-warning, unused-const-variable)
@@ -845,9 +848,6 @@ NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC)
-print-file-name=include)
 # warn about C99 declaration after statement
 KBUILD_CFLAGS += -Wdeclaration-after-statement

-# Warn about unmarked fall-throughs in switch statement.
-KBUILD_CFLAGS += $(call cc-option,-Wimplicit-fallthrough,)
-
 # Variable Length Arrays (VLAs) should not be used anywhere in the kernel
 KBUILD_CFLAGS += -Wvla



-- 
Best Regards
Masahiro Yamada

  parent reply	other threads:[~2019-08-18 16:44 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-15 18:20 [PATCH] kbuild: Require W=1 for -Wimplicit-fallthrough with clang Nathan Huckleberry
2019-08-15 20:45 ` Nathan Chancellor
2019-08-15 22:50   ` Nick Desaulniers
2019-08-15 22:58     ` [PATCH v2] " Nathan Huckleberry
2019-08-15 23:04       ` Nick Desaulniers
2019-08-18 16:43       ` Masahiro Yamada [this message]
2019-08-18 18:43         ` Nathan Chancellor
2019-08-19  3:05           ` Masahiro Yamada
2019-08-27  0:41       ` [PATCH] kbuild: Do not enable -Wimplicit-fallthrough for clang for now Nathan Chancellor
2019-08-28 16:20         ` Masahiro Yamada
2019-08-28 16:44           ` Miguel Ojeda
2019-08-28 17:39             ` Nick Desaulniers
2019-08-28 17:44               ` Nick Desaulniers
2019-08-29 17:18                 ` Masahiro Yamada
2019-08-28 18:02           ` Gustavo A. R. Silva
2019-08-15 22:59   ` [PATCH] kbuild: Require W=1 for -Wimplicit-fallthrough with clang Miguel Ojeda
2019-08-15 23:05     ` Nick Desaulniers
2019-08-15 23:53       ` Miguel Ojeda

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAK7LNATsA0foyeaE2W3xe=_Hkf9S=q0eD5WHqwPXkMw8udkDPg@mail.gmail.com' \
    --to=yamada.masahiro@socionext.com \
    --cc=clang-built-linux@googlegroups.com \
    --cc=joe@perches.com \
    --cc=linux-kbuild@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=michal.lkml@markovi.net \
    --cc=miguel.ojeda.sandonis@gmail.com \
    --cc=natechancellor@gmail.com \
    --cc=nhuck@google.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).