public inbox for gcc@gcc.gnu.org
 help / color / mirror / Atom feed
From: Florian Weimer <fweimer@redhat.com>
To: Thomas Koenig via Gcc <gcc@gcc.gnu.org>
Cc: Thomas Koenig <tkoenig@netcologne.de>
Subject: Re: Calling convention for Intel APX extension
Date: Thu, 27 Jul 2023 15:10:04 +0200	[thread overview]
Message-ID: <87cz0d33gz.fsf@oldenburg3.str.redhat.com> (raw)
In-Reply-To: <4fef10d7-71ea-e31d-3dd5-97ba0994b61c@netcologne.de> (Thomas Koenig via Gcc's message of "Thu, 27 Jul 2023 10:38:25 +0200")

* Thomas Koenig via Gcc:

> Intel recommends to have the new registers as caller-saved for
> compatibility with current calling conventions.  If I understand this
> correctly, this is required for exception unwinding, but not if the
> function called is __attribute__((nothrow)).

Nothrow functions still can call longjmp, so that's probably not the
right discriminator.

For glibc on Linux, we have some extra space in jmpbuf in the signal
mask (we have 1024 bits, but the kernel can use just 64, some of those
have already been repurposed), but it's going to be tough for
cancellation support because of a historic microoptimization there.

Thanks,
Florian


  reply	other threads:[~2023-07-27 13:10 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-27  8:38 Thomas Koenig
2023-07-27 13:10 ` Florian Weimer [this message]
2023-07-27 13:43 ` Michael Matz
2023-07-30 15:33   ` Thomas Koenig
2023-07-31 12:43     ` Michael Matz

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=87cz0d33gz.fsf@oldenburg3.str.redhat.com \
    --to=fweimer@redhat.com \
    --cc=gcc@gcc.gnu.org \
    --cc=tkoenig@netcologne.de \
    /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).