From: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>,
Joe Perches <joe@perches.com>, Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>,
"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<x86@kernel.org>, Kan Liang <kan.liang@linux.intel.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
Kees Cook <keescook@chromium.org>, Shawn Landden <shawn@git.icu>,
Nick Desaulniers <ndesaulniers@google.com>,
Nathan Chancellor <natechancellor@gmail.com>,
Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Subject: Re: [PATCH] perf/x86/intel: Mark expected switch fall-throughs
Date: Tue, 25 Jun 2019 14:47:29 +0200 [thread overview]
Message-ID: <CANiq72=zzZ+Cx8uM+5UW7HeB9XtbXRhXmC2y2tz5EzPX77gHMw@mail.gmail.com> (raw)
In-Reply-To: <20190625071846.GN3436@hirez.programming.kicks-ass.net>
On Tue, Jun 25, 2019 at 9:19 AM Peter Zijlstra <peterz@infradead.org> wrote:
>
> Can it build a kernel without patches yet? That is, why should I care
> what LLVM does?
Having more than a single compiler is always a good idea. You benefit
from more warnings, more tooling, a second implementation for
reference/comparison, etc.
As for what is the current state, I think they are close, specially
for aarch64, but I let Nick, Nathan et. al. answer that! :-) (Cc'd).
They had a talk in FOSDEM 2019 about it, too.
Also CC'ing Luc since he changed sparse to stop ignoring the attribute
so that __has_attribute() would work, but I am not sure if there has
been further work on supporting it properly.
> > Also note that C2x may get [[fallthrough]]. See N2267 and N2335. At
> > that point, surely tools/IDEs/analyzers will support it :-) The
> > question is whether we want to wait that long to replace the comments.
>
> #define __fallthrough [[fallthrough]]
>
> right?
Yes and no. The exact spelling we use does not matter much. My point
with that paragraph was that since C2x will (maybe) add fallthrough,
as C++17 did, every compiler/analyzer/IDE/etc. that is still missing
support for it will have to eventually add it even if they ignore GNU
attributes. At that point, I would guess most will likely add all
spellings too.
Cheers,
Miguel
next prev parent reply other threads:[~2019-06-25 12:47 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-24 16:19 [PATCH] perf/x86/intel: Mark expected switch fall-throughs Gustavo A. R. Silva
2019-06-24 19:31 ` Peter Zijlstra
2019-06-24 19:45 ` Joe Perches
2019-06-24 20:37 ` Peter Zijlstra
2019-06-24 20:53 ` Gustavo A. R. Silva
2019-06-24 20:57 ` Joe Perches
2019-06-25 7:20 ` Peter Zijlstra
2019-06-24 22:28 ` Miguel Ojeda
2019-06-25 7:18 ` Peter Zijlstra
2019-06-25 12:47 ` Miguel Ojeda [this message]
2019-06-25 18:15 ` Nick Desaulniers
2019-06-25 22:29 ` Joe Perches
2019-06-25 22:57 ` Nick Desaulniers
2019-06-25 23:25 ` Joe Perches
2019-06-26 8:49 ` Peter Zijlstra
2019-06-26 22:14 ` Nick Desaulniers
2019-06-27 7:12 ` Peter Zijlstra
2019-06-28 13:31 ` Peter Zijlstra
2019-06-28 18:44 ` Nick Desaulniers
2019-06-29 7:10 ` Peter Zijlstra
2019-06-25 17:12 ` Kees Cook
2019-06-25 18:05 ` Nathan Chancellor
2019-06-25 19:53 ` Thomas Gleixner
2019-06-25 20:27 ` Nathan Chancellor
2019-06-25 20:37 ` Nick Desaulniers
2019-06-25 21:47 ` Thomas Gleixner
2019-06-26 5:10 ` Nathan Chancellor
2019-06-26 15:18 ` Thomas Gleixner
2019-06-26 19:00 ` Nathan Chancellor
2019-06-26 19:46 ` Thomas Gleixner
2019-06-26 20:03 ` Nathan Chancellor
2019-06-26 9:24 ` Peter Zijlstra
2019-06-26 9:55 ` Peter Zijlstra
2019-06-26 22:23 ` Nick Desaulniers
2019-06-27 7:35 ` Peter Zijlstra
2019-06-26 10:43 ` Peter Zijlstra
2019-06-26 22:15 ` Nick Desaulniers
2019-06-27 7:16 ` Peter Zijlstra
2019-06-26 16:30 ` Peter Zijlstra
2019-06-26 22:33 ` Nick Desaulniers
2019-06-26 23:11 ` Thomas Gleixner
2019-06-27 7:11 ` Peter Zijlstra
2019-06-25 23:46 ` Arnaldo Carvalho de Melo
2019-06-26 5:14 ` Nathan Chancellor
2019-06-25 20:09 ` Kees Cook
2019-06-26 8:06 ` Peter Zijlstra
2019-06-25 7:15 ` Peter Zijlstra
2019-07-25 16:27 ` [tip:perf/urgent] " tip-bot for Gustavo A. R. Silva
2019-07-25 17:06 ` Borislav Petkov
2019-07-25 17:35 ` Peter Zijlstra
2019-07-25 23:18 ` Joe Perches
2019-07-25 23:28 ` Kees Cook
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