From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by sourceware.org (Postfix) with ESMTPS id 270F63857813 for ; Wed, 10 Nov 2021 12:05:11 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 270F63857813 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-603-hEeAB5MqNA6NkcME7i5l5A-1; Wed, 10 Nov 2021 07:05:07 -0500 X-MC-Unique: hEeAB5MqNA6NkcME7i5l5A-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A1E3D1006AA0; Wed, 10 Nov 2021 12:05:06 +0000 (UTC) Received: from localhost (unknown [10.33.36.17]) by smtp.corp.redhat.com (Postfix) with ESMTP id 514E710495B0; Wed, 10 Nov 2021 12:05:06 +0000 (UTC) From: Jonathan Wakely To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org Subject: [committed] libstdc++: Disable gthreads weak symbols for glibc 2.34 [PR103133] Date: Wed, 10 Nov 2021 12:05:05 +0000 Message-Id: <20211110120505.2843952-1-jwakely@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" X-Spam-Status: No, score=-14.1 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=unavailable autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libstdc++@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libstdc++ mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 10 Nov 2021 12:05:12 -0000 Tested powerpc64le-linux, glibc 2.17 and 2.34, pushed to trunk. We also want something like this for musl-based targets. And Florian has suggested we should also disable the weak symbols for libstdc++.a, but those need more work. ... Since Glibc 2.34 all pthreads symbols are defined directly in libc not libpthread, and since Glibc 2.32 we have used __libc_single_threaded to avoid unnecessary locking in single-threaded programs. This means there is no reason to avoid linking to libpthread now, and so no reason to use weak symbols defined in gthr-posix.h for all the pthread_xxx functions. libstdc++-v3/ChangeLog: PR libstdc++/100748 PR libstdc++/103133 * config/os/gnu-linux/os_defines.h (_GLIBCXX_GTHREAD_USE_WEAK): Define for glibc 2.34 and later. --- libstdc++-v3/config/os/gnu-linux/os_defines.h | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/libstdc++-v3/config/os/gnu-linux/os_defines.h b/libstdc++-v3/config/os/gnu-linux/os_defines.h index d5bb2a1886e..3a053454195 100644 --- a/libstdc++-v3/config/os/gnu-linux/os_defines.h +++ b/libstdc++-v3/config/os/gnu-linux/os_defines.h @@ -61,4 +61,10 @@ (__gthread_active_p() ? __gthread_self() : (__gthread_t)1) #endif +#if __GLIBC_PREREQ(2, 34) +// Since glibc 2.34 all pthreads functions are usable without linking to +// libpthread. +# define _GLIBCXX_GTHREAD_USE_WEAK 0 +#endif + #endif -- 2.31.1