From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 16541 invoked by alias); 28 Nov 2012 11:27:12 -0000 Received: (qmail 16521 invoked by uid 22791); 28 Nov 2012 11:27:11 -0000 X-SWARE-Spam-Status: No, hits=-7.2 required=5.0 tests=AWL,BAYES_00,KHOP_RCVD_UNTRUST,KHOP_THREADED,RCVD_IN_DNSWL_HI,RCVD_IN_HOSTKARMA_W,RP_MATCHES_RCVD,SPF_HELO_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, 28 Nov 2012 11:26:59 +0000 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id qASBQTD2010941 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Wed, 28 Nov 2012 06:26:29 -0500 Received: from [10.36.116.77] (ovpn-116-77.ams2.redhat.com [10.36.116.77]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id qASBQPMI002617; Wed, 28 Nov 2012 06:26:27 -0500 Subject: Re: [RFC] Wrong register numbers in .dwarf_frame on Linux/PowerPC From: Mark Wielaard To: Ulrich Weigand Cc: dje.gcc@gmail.com, geoffk@geoffk.org, jakub@redhat.com, gcc-patches@gcc.gnu.org, binutils@sourceware.org, gdb-patches@sourceware.org In-Reply-To: <201211271849.qARInCSZ031343@d06av02.portsmouth.uk.ibm.com> References: <201211271849.qARInCSZ031343@d06av02.portsmouth.uk.ibm.com> Content-Type: text/plain; charset="UTF-8" Date: Wed, 28 Nov 2012 11:27:00 -0000 Message-ID: <1354101985.3668.4.camel@bordewijk.wildebeest.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2012-11/txt/msg00805.txt.bz2 On Tue, 2012-11-27 at 19:49 +0100, Ulrich Weigand wrote: > Mark Wielaard wrote: > > > Which other unwinders are out there, that might rely on the current > > numbering? > > Well, runtime unwinders using .eh_frame should be fine, since this > uses (and has always used) consistently the GCC numbering. I don't > know if there are other unwinders using .dwarf_frame ... The reason systemtap hits this is that it can do unwinding of both user and kernel space. The linux kernel doesn't include eh_frames, so we have to fall back to .debug_frame. > The change will most likely be to consistently use GCC numbering in > .dwarf_frame as well, which changes only the encoding of the condition > code register. Since you're not using that at all in systemtap, you > shouldn't be affected. Yeah, we only use the unwinder currently to produce backtraces, which are unlikely to rely on the condition code register. > As far as Linux goes, yes, ppc was the only architecture with a > different encoding between .eh_frame and .dwarf_frame. In that case your option 3 seems ideal. Thanks, Mark