From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 16196 invoked by alias); 13 Jun 2011 17:14:15 -0000 Received: (qmail 16175 invoked by uid 22791); 13 Jun 2011 17:14:14 -0000 X-SWARE-Spam-Status: No, hits=-2.0 required=5.0 tests=AWL,BAYES_00,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from sunsite.ms.mff.cuni.cz (HELO sunsite.mff.cuni.cz) (195.113.15.26) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 13 Jun 2011 17:13:59 +0000 Received: from sunsite.mff.cuni.cz (localhost [127.0.0.1]) by sunsite.mff.cuni.cz (8.14.4/8.14.4) with ESMTP id p5DHDsA2025043; Mon, 13 Jun 2011 19:13:54 +0200 Received: (from jj@localhost) by sunsite.mff.cuni.cz (8.14.4/8.14.4/Submit) id p5DHDrpA025042; Mon, 13 Jun 2011 19:13:53 +0200 Date: Mon, 13 Jun 2011 17:14:00 -0000 From: Jakub Jelinek To: Richard Henderson Cc: libc-alpha@sourceware.org, binutils@sourceware.org, gdb@sourceware.org, Mark Wielaard , Frank Eigler Subject: Re: RFC: Unwind info for PLT Message-ID: <20110613171352.GY11563@sunsite.ms.mff.cuni.cz> Reply-To: Jakub Jelinek References: <20110610074524.GR17079@tyan-ft48-01.lab.bos.redhat.com> <4DF23519.7050607@twiddle.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4DF23519.7050607@twiddle.net> User-Agent: Mutt/1.5.21 (2010-09-15) 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/msg00092.txt.bz2 On Fri, Jun 10, 2011 at 08:15:37AM -0700, Richard Henderson wrote: > 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? Yeah, easier to write and easier to change. Anyway, if you prefer to do it in ld, I can try to do it there. Just a question, should it be done unconditionally, or guarded with some ld cmdline option (either existing one, like abuse --eh-frame-hdr for it, or a new one)? On other targets like SPARC or PowerPC -mbss-plt it is the dynamic linker which updates or completely writes .plt section though, should in that case the dynamic linker provide the unwind info instead? > 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. Ok. Jakub