public inbox for gcc-help@gcc.gnu.org
 help / color / mirror / Atom feed
From: Jonathan Wakely <jwakely.gcc@gmail.com>
To: David Brown <david.brown@hesbynett.no>
Cc: gcc-help <gcc-help@gcc.gnu.org>
Subject: Re: Atomic accesses on ARM microcontrollers
Date: Sat, 10 Oct 2020 21:18:05 +0100	[thread overview]
Message-ID: <CAH6eHdRJxBgkhbhjuY2VSjOs5xqXdOhnOW9u3a9BqC1qs=hoUw@mail.gmail.com> (raw)
In-Reply-To: <6cfc20a9-05c5-e2be-d9f0-d10911268b4a@hesbynett.no>

On Sat, 10 Oct 2020 at 20:43, David Brown <david.brown@hesbynett.no> wrote:
> Is this strategy guaranteed to work in gcc, or is it a case of "it works
> in a simple test, but might fail in a complicated program or with
> different flags" ?

I think it works by design. My understanding is that users providing
their own implementation of those calls is fully supported. I think
that's partly why libatomic.so is a distinct library, and not just
part of libgcc_s.so. The docs aren't entirely clear about this, they
just say that if the compiler can't emit lock-free instructions for
the atomic operation "a call is made to an external routine with the
same parameters to be resolved at run time." But I think that "to be
resolved at run time" means that you can choose how those calls will
be resolved.

  reply	other threads:[~2020-10-10 20:18 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-09 18:28 David Brown
2020-10-09 23:28 ` Segher Boessenkool
2020-10-10 12:39 ` Jonathan Wakely
2020-10-10 19:43   ` David Brown
2020-10-10 20:18     ` Jonathan Wakely [this message]
2020-10-11 10:54       ` David Brown
2020-10-12  7:17     ` David Brown
2020-10-12 21:44   ` Patrick Oppenlander
     [not found] ` <b29b1595-9441-68eb-f257-244a35082c82@winterflaw.net>
2020-10-10 19:43   ` David Brown
2020-10-10 20:09     ` Jonathan Wakely
     [not found]     ` <bdf0f96f-0377-bee7-c02e-9704f0bea6a5@winterflaw.net>
2020-10-11 12:16       ` David Brown
     [not found]         ` <24c49c76-43c3-9a0d-6b02-a4340b1fccba@winterflaw.net>
2020-10-11 12:51           ` David Brown
2020-10-13 11:46             ` Richard Earnshaw

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='CAH6eHdRJxBgkhbhjuY2VSjOs5xqXdOhnOW9u3a9BqC1qs=hoUw@mail.gmail.com' \
    --to=jwakely.gcc@gmail.com \
    --cc=david.brown@hesbynett.no \
    --cc=gcc-help@gcc.gnu.org \
    /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 read-only IMAP folder(s) and NNTP newsgroup(s).