From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 119980 invoked by alias); 25 Apr 2016 17:35:59 -0000 Mailing-List: contact binutils-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: binutils-owner@sourceware.org Received: (qmail 119914 invoked by uid 89); 25 Apr 2016 17:35:58 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00,KAM_LAZY_DOMAIN_SECURITY,RP_MATCHES_RCVD,SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=Hx-languages-length:1289 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Mon, 25 Apr 2016 17:35:48 +0000 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7F0523455AA; Mon, 25 Apr 2016 17:35:47 +0000 (UTC) Received: from localhost.localdomain (ovpn-113-93.phx2.redhat.com [10.3.113.93]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u3PHZkmv002984; Mon, 25 Apr 2016 13:35:47 -0400 Subject: Re: Preventing preemption of 'protected' symbols in GNU ld 2.26 [aka should we revert the fix for 65248] To: Richard Biener , Alan Modra References: <6AAD87D2-90F9-4AD7-A195-AC91B76EA6AE@apple.com> <56FB5061.9010303@redhat.com> <20160330143421.GM15812@bubble.grove.modra.org> <571161D0.10601@redhat.com> <20160418144911.GG15088@bubble.grove.modra.org> <20160419050805.GI15088@bubble.grove.modra.org> Cc: "H.J. Lu" , Cary Coutant , Joe Groff , Binutils , GCC From: Jeff Law Message-ID: <08719312-4e17-21f9-7513-6ad4b92833fc@redhat.com> Date: Mon, 25 Apr 2016 17:35:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2016-04/txt/msg00419.txt.bz2 On 04/19/2016 02:20 AM, Richard Biener wrote: > On Tue, Apr 19, 2016 at 7:08 AM, Alan Modra wrote: >> On Mon, Apr 18, 2016 at 07:59:50AM -0700, H.J. Lu wrote: >>> On Mon, Apr 18, 2016 at 7:49 AM, Alan Modra wrote: >>>> On Mon, Apr 18, 2016 at 11:01:48AM +0200, Richard Biener wrote: >>>>> To summarize: there is currently no testcase for a wrong-code issue >>>>> because there is no wrong-code issue. >> >> I've added a testcase at >> https://sourceware.org/bugzilla/show_bug.cgi?id=19965#c3 >> that shows the address problem (&x != x) with older gcc *or* older >> glibc, and shows the program behaviour problem with current >> binutils+gcc+glibc. > > Thanks. > > So with all this it sounds that current protected visibility is just broken > and we should forgo with it, making it equal to default visibility? No, we revert to the gcc-4.9 behavior WRT protected visibility and ensure that we're getting a proper diagnostic from the linker. That direction is consistent with the intent of protected visibility, fixes the problem with preemption of protected symbols and gives us a diagnostic for the case that can't be reasonably handled. Jeff