From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 25286 invoked by alias); 10 Jul 2008 02:46:38 -0000 Received: (qmail 25278 invoked by uid 22791); 10 Jul 2008 02:46:37 -0000 X-Spam-Check-By: sourceware.org Received: from bluesmobile.specifix.com (HELO bluesmobile.specifix.com) (216.129.118.140) by sourceware.org (qpsmtpd/0.31) with ESMTP; Thu, 10 Jul 2008 02:46:13 +0000 Received: from [127.0.0.1] (bluesmobile.specifix.com [216.129.118.140]) by bluesmobile.specifix.com (Postfix) with ESMTP id 0ABD43C163; Wed, 9 Jul 2008 19:46:11 -0700 (PDT) Subject: Re: [RFA] set/show enable-software-singlestep From: Michael Snyder To: Pedro Alves Cc: Daniel Jacobowitz , gdb-patches@sourceware.org, Joel Brobecker In-Reply-To: <1214862215.3601.1525.camel@localhost.localdomain> References: <1214331534.3601.1211.camel@localhost.localdomain> <200806251514.40869.pedro@codesourcery.com> <20080625144215.GA12011@caradoc.them.org> <200806251603.51908.pedro@codesourcery.com> <1214862215.3601.1525.camel@localhost.localdomain> Content-Type: text/plain Date: Thu, 10 Jul 2008 02:46:00 -0000 Message-Id: <1215657970.3549.157.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.10.3 (2.10.3-7.fc7) Content-Transfer-Encoding: 7bit X-IsSubscribed: yes 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: 2008-07/txt/msg00142.txt.bz2 Silence equals assent? On Mon, 2008-06-30 at 14:43 -0700, Michael Snyder wrote: > Any convergence on this? > > On Wed, 2008-06-25 at 16:03 +0100, Pedro Alves wrote: > > A Wednesday 25 June 2008 15:42:15, Daniel Jacobowitz escreveu: > > > On Wed, Jun 25, 2008 at 03:14:38PM +0100, Pedro Alves wrote: > > > > A Wednesday 25 June 2008 14:34:57, Daniel Jacobowitz wrote: > > > > > I think it should already be auto. can-use-software-singlestep is > > > > > unintuitive - either do use it, don't use it, or use GDB's best > > > > > judgement. And if the user selects to use it and it isn't supported, > > > > > that's an error when we next want to singlestep. WDYT? > > > > > > > > Well, not really auto. If a ARM stub does software singlestepping itself > > > > (say we add it to gdbserver), gdb will still do software > > > > single-stepping (breakpoint dance), wont it? > > > > > > What Joel said elsewhere in the thread just now. If we get a stub > > > that reports definitively that it can single step, that should take > > > priority over GDB knowing that software singlestep is implemented for > > > this architecture. > > > > > > > What I said elsewhere in the thread just now. :-) The stub should > > report it, and a new target method is required, that takes precedence > > for stepping operations. > > > > > Um, uh-oh. This will break the overloading of software single step > > > for bypassing atomic operations. Clearly more thought is required! > > > > > > > The stub should just either step it all atomically, and GDB sees > > only one SIGTRAP, or we force continuing over the sequence with a > > single-step breakpoint (as we do today), not telling the > > stub to step at all (as we don't do today...). We seems we need > > to distinguish this in the reporting mechanism. Another issue is > > that the atomic operations bypassing is implemented inside > > the software_singlestepping gdbarch methods. It should be > > factored out. > > > > > Another unfortunate note: we can't trust the vCont reply for this even > > > though it's clearly the right thing :-( Since current versions of GDB > > > reject replies without s/S. > > > > Yep, I noticed that. We'll need something else, probably > > qSupported (if we're thinking of supporting multi arch > > stubs, care must be taken here as well). > > >