From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 16958 invoked by alias); 2 Sep 2009 16:46:51 -0000 Received: (qmail 16822 invoked by uid 22791); 2 Sep 2009 16:46:50 -0000 X-SWARE-Spam-Status: No, hits=-2.3 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 02 Sep 2009 16:46:41 +0000 Received: from int-mx04.intmail.prod.int.phx2.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.17]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id n82Gka54019146; Wed, 2 Sep 2009 12:46:36 -0400 Received: from freie.oliva.athome.lsd.ic.unicamp.br (ovpn01.gateway.prod.ext.phx2.redhat.com [10.5.9.1]) by int-mx04.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id n82GkY82003404 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 2 Sep 2009 12:46:35 -0400 Received: from huru.localdomain (huru.oliva.athome.lsd.ic.unicamp.br [172.31.160.8]) by freie.oliva.athome.lsd.ic.unicamp.br (8.14.3/8.14.3) with ESMTP id n82GkYaq009939; Wed, 2 Sep 2009 13:46:34 -0300 Received: from huru.localdomain (aoliva@localhost [127.0.0.1]) by huru.localdomain (8.14.3/8.14.3/Debian-5) with ESMTP id n82GkXv9014395; Wed, 2 Sep 2009 13:46:33 -0300 Received: (from aoliva@localhost) by huru.localdomain (8.14.3/8.14.3/Submit) id n82GkWDI014393; Wed, 2 Sep 2009 13:46:32 -0300 From: Alexandre Oliva To: gcc@gcc.gnu.org Subject: VTA bootstrap compare failures Date: Wed, 02 Sep 2009 16:46:00 -0000 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-owner@gcc.gnu.org X-SW-Source: 2009-09/txt/msg00049.txt.bz2 Along with the VTA merge, a change was installed that made bootstrap-debug BUILD_CONFIG the default. This means stage2 is built with -g0, and stage3 is built with -g, and then we compare the object files after stripping them. Although this works fine on numerous GNU/Linux platforms on which I tested it, and the bootstrap-debug option has been available and recommended, even in the trunk, for quite a while, without any problem reports whatsoever, making it default immediately showed it hadn't got much testing elsewhere :-( PRs 41224 and 41228 are the ones I know about. Basically, the problem is that stripping is not enough to get identical object files. Significant differences remain, even after stripping. So I guess we'll have to find a way to enable bootstrap-debug only when this works. I can't think of a way to test whether it comparing stripped -g0 and -g object files works using the stage1 compiler, but I guess if we test the compiler used to build stage1 and that works, we should strive to ensure the stage1 compiler works as well. So tonight I'll write a patch that performs a contrib/compare-debug test and enables or disables BUILD_CONFIG=bootstrap-debug accordingly. I hereby ask for help, as mentioned in the bug reports, in coming up with a minimal testcase that is enough to fail contrib/compare-debug on the affected platforms. I assume a trivial main(){} wouldn't do, but perhaps even that might. If you are willing to help, please test: cat > test.c << EOF void f() {} EOF gcc -c -g0 test.c -o test-g0.o gcc -c -g test.c -o test-g.o .../gcc/contrib/compare-debug test-g0.o test-g.o echo $? If it prints 0 at the end, this is too simple a testcase, and we need something more complex to trigger a compare error. If it prints 1, we have something we can use. Now, if you're not interested in helping come up with this minimal testcase, but still want bootstrap to pass, please drop bootstrap-debug from the BUILD_CONFIG line in Makefile.in, or override BUILD_CONFIG in the make command line. If anyone feels this is serious and urgent enough to deserve a reversal, please revert only the Makefile.* changes. I won't be around much for the next 6 hours or so, but I'll deal with it as soon as I return. Thanks, -- Alexandre Oliva, freedom fighter http://FSFLA.org/~lxoliva/ You must be the change you wish to see in the world. -- Gandhi Be Free! -- http://FSFLA.org/ FSF Latin America board member Free Software Evangelist Red Hat Brazil Compiler Engineer