From: Alexey Dobriyan <adobriyan@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Drop -Wdeclaration-after-statement
Date: Tue, 12 Mar 2019 20:24:47 +0300 [thread overview]
Message-ID: <20190312172447.GA10166@avx2> (raw)
In-Reply-To: <20190311173845.53c2e4e4d2257a3701fa2033@linux-foundation.org>
On Mon, Mar 11, 2019 at 05:38:45PM -0700, Andrew Morton wrote:
> On Sun, 10 Mar 2019 16:35:35 +0300 Alexey Dobriyan <adobriyan@gmail.com> wrote:
>
> > Newly added static_assert() is formally a declaration, which will give
> > a warning if used in the middle of the function.
> >
> > ...
> >
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -792,9 +792,6 @@ endif
> > # arch Makefile may override CC so keep this after arch Makefile is included
> > NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)
> >
> > -# warn about C99 declaration after statement
> > -KBUILD_CFLAGS += -Wdeclaration-after-statement
> > -
> > # Variable Length Arrays (VLAs) should not be used anywhere in the kernel
> > KBUILD_CFLAGS += $(call cc-option,-Wvla)
>
> I do wish your changelogs were more elaborate :(
> So the proposal is to disable -Wdeclaration-after-statement in all
> cases for all time because static_assert() doesn't work correctly?
Yes. I converted 2 cases in /proc to static_assert() and you can't write
{
[code]
static_assert()
}
without a warning because static_assert() is declaration.
So people would move BUILD_BUG_ON() to where it doesn't belong.
> Surely there's something we can do to squish the static_assert() issue
> while retaining -Wdeclaration-after-statement?
It is not good in my opinion to stick to -Wdeclaration-after-statement.
> Perhaps by making
> static_assert() a nop if -Wdeclaration-after-statement is in use.
> Perhaps simply by putting { } around the static_assert()?
Making a statement out of it would disable current cases where it is
placed in headers.
next prev parent reply other threads:[~2019-03-12 17:24 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-10 13:35 [PATCH] Drop -Wdeclaration-after-statement Alexey Dobriyan
2019-03-12 0:38 ` Andrew Morton
2019-03-12 17:24 ` Alexey Dobriyan [this message]
2019-03-12 19:50 ` Andrew Morton
2019-03-12 20:18 ` Alexey Dobriyan
2019-03-12 20:53 ` Andrew Morton
2019-03-12 20:24 ` Alexey Dobriyan
2022-02-25 8:15 Alexey Dobriyan
2022-02-25 10:01 ` David Laight
2022-02-25 17:24 ` Alexey Dobriyan
2022-02-26 1:10 ` Andrew Morton
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