From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 29161 invoked by alias); 8 Nov 2007 16:11:27 -0000 Received: (qmail 29144 invoked by uid 22791); 8 Nov 2007 16:11:26 -0000 X-Spam-Check-By: sourceware.org Received: from mail.suse.de (HELO mx1.suse.de) (195.135.220.2) by sourceware.org (qpsmtpd/0.31) with ESMTP; Thu, 08 Nov 2007 16:11:20 +0000 Received: from Relay2.suse.de (mail2.suse.de [195.135.221.8]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.suse.de (Postfix) with ESMTP id 94F7C1B10C; Thu, 8 Nov 2007 17:11:17 +0100 (CET) Date: Thu, 08 Nov 2007 16:11:00 -0000 From: Michael Matz To: Robert Dewar Cc: Alexandre Oliva , Richard Guenther , gcc-patches@gcc.gnu.org, gcc@gcc.gnu.org Subject: Re: Designs for better debug info in GCC In-Reply-To: <47331636.9010308@adacore.com> Message-ID: References: <84fc9c000711050327x74845c78ya18a3329fcf9e4d2@mail.gmail.com> <47331636.9010308@adacore.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-IsSubscribed: yes Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org X-SW-Source: 2007-11/txt/msg00428.txt.bz2 Hi, On Thu, 8 Nov 2007, Robert Dewar wrote: > significantly degraded -O1 debugging. I have found for > instance that debugging the GNAT compiler itself, -O1 > used to be perfectly fine, but now far too many arguments > and variables disappear. Yes. That problem is addressed by Alexandre's approach and by ours. If you want to be really sure no arguments disappear (necessary for instance for meaningful use of systemtap) you also need to inhibit some transformations, which can be done under a certain option (which might or might not be on by default for -O1). > 3. The quality of code at -O0 is really terrible compared > to the competition (at least in the case of Ada), and > large scale programs are just too big at -O0 to be > practical (there is a big difference between a 50 > megabyte image and a 100 megabyte image). This is a problem on it's own. We're planning to work on this somewhen during the next months, i.e. improve code quality at -O0 at least to a point it was in the 3.x line of GCC. Ciao, Michael.