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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	[thread overview]
Message-ID: <bug-97182-4@http.gcc.gnu.org/bugzilla/> (raw)

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97182

            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 they
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 defined 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

             reply	other threads:[~2020-09-23 17:23 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-23 17:23 redi at gcc dot gnu.org [this message]
2020-09-23 17:28 ` [Bug libstdc++/97182] " redi at gcc dot gnu.org
2020-09-23 18:47 ` jakub at gcc dot gnu.org
2020-09-23 19:27 ` wilson at gcc dot gnu.org
2020-09-23 19:35 ` jakub at gcc dot gnu.org
2020-09-24 23:09 ` wilson at gcc dot gnu.org

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