From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 27181 invoked by alias); 10 Jun 2011 15:15:57 -0000 Received: (qmail 27157 invoked by uid 22791); 10 Jun 2011 15:15:56 -0000 X-SWARE-Spam-Status: No, hits=-1.0 required=5.0 tests=AWL,BAYES_00,DKIM_SIGNED,DKIM_VALID,FREEMAIL_ENVFROM_END_DIGIT,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,RFC_ABUSE_POST X-Spam-Check-By: sourceware.org Received: from mail-qw0-f41.google.com (HELO mail-qw0-f41.google.com) (209.85.216.41) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Fri, 10 Jun 2011 15:15:42 +0000 Received: by qwa26 with SMTP id 26so1853679qwa.0 for ; Fri, 10 Jun 2011 08:15:41 -0700 (PDT) Received: by 10.236.161.228 with SMTP id w64mr2707188yhk.140.1307718941166; Fri, 10 Jun 2011 08:15:41 -0700 (PDT) Received: from anchor.twiddle.net (c-71-227-161-214.hsd1.wa.comcast.net [71.227.161.214]) by mx.google.com with ESMTPS id g5sm776884yhm.82.2011.06.10.08.15.39 (version=TLSv1/SSLv3 cipher=OTHER); Fri, 10 Jun 2011 08:15:40 -0700 (PDT) Message-ID: <4DF23519.7050607@twiddle.net> Date: Fri, 10 Jun 2011 15:15:00 -0000 From: Richard Henderson User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110428 Fedora/3.1.10-1.fc15 Thunderbird/3.1.10 MIME-Version: 1.0 To: Jakub Jelinek CC: libc-alpha@sourceware.org, binutils@sourceware.org, gdb@sourceware.org, Mark Wielaard , Frank Eigler Subject: Re: RFC: Unwind info for PLT References: <20110610074524.GR17079@tyan-ft48-01.lab.bos.redhat.com> In-Reply-To: <20110610074524.GR17079@tyan-ft48-01.lab.bos.redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Mailing-List: contact gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org X-SW-Source: 2011-06/txt/msg00072.txt.bz2 On 06/10/2011 12:45 AM, Jakub Jelinek wrote: > Anyway, I think hardcoding this in the linker would be problematic, > we couldn't tweak it, so providing some special hidden symbols around > the .plt section and let glibc crtfiles provide it sounds like the best > option to me. Would it be problematic beyond the fact that it's easier to write the directives in assembler than it is within bfd? We couldn't tweak it, sure, but don't we need to tweak the linker anyway if the PLT gets changed? It seems more logical to me to emit this within the linker itself. As for the actual unwind info, I agree that using pointer arithmetic is the better expression over decoding the insns. Increasing the alignment is probably a good idea, also for the actual decoding of the insns on the real hardware. r~