From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
 id C07043950C24; Wed, 23 Sep 2020 17:23:16 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org C07043950C24
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
 s=default; t=1600881796;
 bh=UQeoDq27pMV0xxFfSYYVFclcNd7uVbo5koew0axprrU=;
 h=From:To:Subject:Date:From;
 b=VDus+Q+t2ROQMlE00J3a1TsACOBv/PWcChY7dDPQIQNHEADmyMypPX25St3p2aH5/
 yWlZRR/lynstPt+peKEpzJaS5qyVJZpHerjQHc1InnjNDz8e1e5VYyQZJmrKnwDGFz
 KdwSaSB2AiLumDtn9AwF9UFnejDpvjeuwBGLo1NA=
From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/97182] New: Add support for targets that only define
 SYS_futex_time64 and not SYS_futex
Date: Wed, 23 Sep 2020 17:23:16 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: libstdc++
X-Bugzilla-Version: 11.0
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: redi at gcc dot gnu.org
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: bug_id short_desc product version bug_status
 bug_severity priority component assigned_to reporter target_milestone
Message-ID: <bug-97182-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-BeenThere: gcc-bugs@gcc.gnu.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Gcc-bugs mailing list <gcc-bugs.gcc.gnu.org>
List-Unsubscribe: <https://gcc.gnu.org/mailman/options/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=unsubscribe>
List-Archive: <https://gcc.gnu.org/pipermail/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-request@gcc.gnu.org?subject=help>
List-Subscribe: <https://gcc.gnu.org/mailman/listinfo/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=subscribe>
X-List-Received-Date: Wed, 23 Sep 2020 17:23:16 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D97182

            Bug ID: 97182
           Summary: Add support for targets that only define
                    SYS_futex_time64 and not SYS_futex
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: redi at gcc dot gnu.org
  Target Milestone: ---

I'm told this affects 32-bit RISC-V.

If SYS_futex isn't defined then libstdc++ won't use futexes, even though th=
ey
might be available via the new SYS_futex_time64 syscall instead.

The autoconf checks for SYS_futex should be updated to look for
SYS_futex_time64 as well, and then src/c++11/futex.cc needs to use the best=
 one
available, and possibly have a fallback for the case where both were define=
d at
configure time but one returns ENOSYS at runtime. Ugh.

This probably also affects our uses of SYS_clock_gettime in both
src/c++11/futex.cc and src/c++11/chrono.cc=