From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 29642 invoked by alias); 4 Sep 2008 14:05:10 -0000 Received: (qmail 29621 invoked by uid 22791); 4 Sep 2008 14:05:09 -0000 X-Spam-Check-By: sourceware.org Received: from aussmtpmrkps320.us.dell.com (HELO aussmtpmrkps320.us.dell.com) (143.166.224.254) by sourceware.org (qpsmtpd/0.31) with ESMTP; Thu, 04 Sep 2008 14:04:28 +0000 X-IronPort-AV: E=Sophos;i="4.32,320,1217826000"; d="scan'208";a="370255127" Received: from unknown (HELO M31.equallogic.com) ([12.110.134.31]) by aussmtpmrkps320.us.dell.com with SMTP; 04 Sep 2008 09:04:27 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <18623.60121.742830.903401@gargle.gargle.HOWL> Date: Thu, 04 Sep 2008 14:05:00 -0000 From: Paul Koning To: dewar@adacore.com Cc: schwab@suse.de, eliz@gnu.org, fche@redhat.com, msnyder@vmware.com, brobecker@adacore.com, jreiver@free.fr, gdb@sourceware.org Subject: Re: how to examine data with compiler optimization option set? References: <1220390777.48bdaf79617dd@imp.free.fr> <48BDB1B0.4040703@adacore.com> <1220391632.48bdb2d04bfd7@imp.free.fr> <48BDB4E2.9010301@adacore.com> <20080902215623.GA3779@adacore.com> <48BDD4B7.5060503@vmware.com> <48BF04C6.8030108@adacore.com> <48BFBE10.30902@adacore.com> X-Mailer: VM 7.17 under 21.4 (patch 19) "Constant Variable" XEmacs Lucid X-IsSubscribed: yes 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: 2008-09/txt/msg00026.txt.bz2 >>>>> "Robert" == Robert Dewar writes: Robert> Andreas Schwab wrote: >> Robert Dewar writes: >> >>> Well you always had local variables disappearing in earlier >>> versions but enough worked so you could debug, in particular >>> parameters were always available and reliable. >> If parameters are passed in registers they are very likely to get >> lost. Even on i386 parameters sometimes get passed in registers, >> eg. when calling local functions. Robert> Yes, indeed parameters do get lost and I find it impossible Robert> in practice to debug at -O1 (whereas this was ny normal Robert> practice for many years). Robert> What I am saying is that if an effort is put in to improve Robert> the debugging information, for me this would be the primary Robert> target. Is the problem inadequate debug information (i.e., the values are there, but there isn't debug data that points to the correct registers or stack slots) -- or is the problem that the values you want to see are dead by the time you get to them and the registers holding them have been reused by then? Or something in between, i.e., the values are technically dead, but the registers have NOT yet been reused so the debug information can (and should) still show where they are. paul