From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 29816 invoked by alias); 13 Jun 2005 22:51:21 -0000 Mailing-List: contact gdb-patches-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sources.redhat.com Received: (qmail 29783 invoked by uid 22791); 13 Jun 2005 22:51:15 -0000 Received: from nevyn.them.org (HELO nevyn.them.org) (66.93.172.17) by sourceware.org (qpsmtpd/0.30-dev) with ESMTP; Mon, 13 Jun 2005 22:51:15 +0000 Received: from drow by nevyn.them.org with local (Exim 4.50) id 1Dhxlv-0003g0-F4; Mon, 13 Jun 2005 18:51:11 -0400 Date: Mon, 13 Jun 2005 22:51:00 -0000 From: Daniel Jacobowitz To: Mark Kettenis Cc: jmolenda@apple.com, gdb-patches@sources.redhat.com Subject: Re: The gdb x86 function prologue parser Message-ID: <20050613225111.GC13598@nevyn.them.org> Mail-Followup-To: Mark Kettenis , jmolenda@apple.com, gdb-patches@sources.redhat.com References: <85C775AE-3B05-431E-96D2-49EA9D1413E6@apple.com> <200506120707.j5C77TL6005645@elgar.sibelius.xs4all.nl> <200506132234.j5DMYtxJ032694@elgar.sibelius.xs4all.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200506132234.j5DMYtxJ032694@elgar.sibelius.xs4all.nl> User-Agent: Mutt/1.5.8i X-SW-Source: 2005-06/txt/msg00175.txt.bz2 On Tue, Jun 14, 2005 at 12:34:55AM +0200, Mark Kettenis wrote: > From: Jason Molenda > Date: Mon, 13 Jun 2005 15:04:51 -0700 > > Ah! Now it starts to make sense. I couldn't understand how this had > been so untested. :) > > The one part I'm curious about -- does gdb get the CFI information > out of gcc's eh_frame section or something? How do developers debug > KDE/GNOME applications, where many functions on their stack are from > optimized libraries that don't have any debug info (except maybe > eh_frame)? It seems like these users should be tripping on these > problems all the time. > > Yup. We prefer .debug_frame but if that's not available we suck in > .eh_frame. So anything that's compiled with -fexceptions (wich > implies all C++ code) basically has usable CFI. > I sometimes wonder whether people are using gdb at all... (me too) > ...then I find it incredibly stupid that vendors of an Open Source > operating system ship libraries without debugging information. More and more vendors are shipping libraries with optional debugging information. This is what objcopy --only-keep-debug was invented for. For Debian, I also have a couple of hacks to ship unwind information for some libraries we don't want to provide debug information for by default (like glibc). If you install libc6-dbg, backtraces will suddenly Work Better. No other intervention required. For the next release of Debian I hope we'll be using this feature even more heavily. -- Daniel Jacobowitz CodeSourcery, LLC