From: Joe Perches <joe@perches.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
Kees Cook <keescook@chromium.org>,
Peter Zijlstra <peterz@infradead.org>,
Borislav Petkov <bp@alien8.de>, "H . Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
"Gustavo A . R . Silva" <gustavo@embeddedor.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Kan Liang <kan.liang@linux.intel.com>,
Namhyung Kim <namhyung@kernel.org>, Jiri Olsa <jolsa@redhat.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Shawn Landden <shawn@git.icu>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] compiler_attributes.h: Add 'fallthrough' pseudo keyword for switch/case use
Date: Wed, 31 Jul 2019 10:51:37 -0700 [thread overview]
Message-ID: <ccc7fa72d0f83ddd62067092b105bd801479004b.camel@perches.com> (raw)
In-Reply-To: <20190731171429.GA24222@amd>
On Wed, 2019-07-31 at 19:14 +0200, Pavel Machek wrote:
> On Tue 2019-07-30 22:35:18, Joe Perches wrote:
> > Reserve the pseudo keyword 'fallthrough' for the ability to convert the
> > various case block /* fallthrough */ style comments to appear to be an
> > actual reserved word with the same gcc case block missing fallthrough
> > warning capability.
>
> Acked-by: Pavel Machek <pavel@ucw.cz>
>
> > +/*
> > + * Add the pseudo keyword 'fallthrough' so case statement blocks
> > + * must end with any of these keywords:
> > + * break;
> > + * fallthrough;
> > + * goto <label>;
> > + * return [expression];
> > + *
> > + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Statement-Attributes.html#Statement-Attributes
> > + */
> > +#if __has_attribute(__fallthrough__)
> > +# define fallthrough __attribute__((__fallthrough__))
> > +#else
> > +# define fallthrough do {} while (0) /* fallthrough */
> > +#endif
> > +
>
> Will various checkers (and gcc) recognize, that comment in a macro,
> and disable the warning accordingly?
Current non-gcc tools: I doubt it.
And that's unlikely as the comments are supposed to be stripped
before the macro expansion phase.
gcc 7+, which by now probably most developers actually use, will
though
and likely that's sufficient.
> Explanation that the comment is "magic" might not be a bad idea.
The comment was more for the reader.
cheers, Joe
next prev parent reply other threads:[~2019-07-31 17:51 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-31 5:04 [PATCH] net: sctp: Rename fallthrough label to unhandled Joe Perches
2019-07-31 5:35 ` [RFC PATCH] compiler_attributes.h: Add 'fallthrough' pseudo keyword for switch/case use Joe Perches
2019-07-31 9:02 ` Peter Zijlstra
2019-07-31 9:34 ` Joe Perches
2019-07-31 17:14 ` Pavel Machek
2019-07-31 17:51 ` Joe Perches [this message]
2019-07-31 18:24 ` hpa
2019-07-31 18:48 ` Peter Zijlstra
2019-07-31 20:02 ` Kees Cook
2019-07-31 20:59 ` Miguel Ojeda
2019-07-31 22:07 ` Joe Perches
2019-08-01 0:00 ` Miguel Ojeda
2019-08-01 12:25 ` Peter Zijlstra
2019-08-15 18:15 ` Kees Cook
2019-08-15 22:31 ` Kees Cook
2019-09-16 22:19 ` treewide replacement of fallthrough comments with "fallthrough" macro (was Re: [RFC PATCH] compiler_attributes.h: Add 'fallthrough' pseudo keyword for switch/case use) Kees Cook
2019-09-17 22:26 ` Joe Perches
2019-09-17 23:38 ` Kees Cook
2019-07-31 21:01 ` [RFC PATCH] compiler_attributes.h: Add 'fallthrough' pseudo keyword for switch/case use hpa
2019-07-31 23:55 ` Miguel Ojeda
2019-08-01 6:10 ` hpa
2019-08-01 7:52 ` Joe Perches
2019-08-01 12:24 ` Peter Zijlstra
2019-08-01 20:09 ` hpa
2019-08-01 20:26 ` Miguel Ojeda
2019-08-01 20:47 ` Joe Perches
2019-08-02 11:00 ` Neil Horman
2019-08-02 12:34 ` Pavel Machek
2019-08-02 16:09 ` Kees Cook
2019-08-02 16:16 ` Joe Perches
2019-08-04 18:01 ` Joe Perches
2019-08-04 18:09 ` Linus Torvalds
2019-08-04 19:38 ` Miguel Ojeda
2019-08-05 0:39 ` Joe Perches
2019-08-05 1:18 ` Nathan Chancellor
2019-08-05 2:01 ` Joe Perches
2019-07-31 11:19 ` [PATCH] net: sctp: Rename fallthrough label to unhandled Neil Horman
2019-07-31 11:32 ` Joe Perches
2019-07-31 12:16 ` Neil Horman
2019-07-31 16:35 ` Joe Perches
2019-07-31 20:58 ` Neil Horman
2019-07-31 22:23 ` Joe Perches
2019-08-01 10:50 ` Neil Horman
2019-08-01 17:42 ` Joe Perches
2019-08-01 20:48 ` Neil Horman
2019-08-05 11:49 ` David Laight
2019-08-02 17:47 ` Joe Perches
2019-08-02 23:19 ` David Miller
2019-08-02 23:26 ` Joe Perches
2019-08-03 18:01 ` Joe Perches
2019-08-04 19:26 ` Neil Horman
2019-08-02 17:50 ` Neil Horman
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