From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 17091 invoked by alias); 16 Oct 2008 12:35:08 -0000 Received: (qmail 17078 invoked by uid 22791); 16 Oct 2008 12:35:07 -0000 X-Spam-Check-By: sourceware.org Received: from NaN.false.org (HELO nan.false.org) (208.75.86.248) by sourceware.org (qpsmtpd/0.31) with ESMTP; Thu, 16 Oct 2008 12:34:25 +0000 Received: from nan.false.org (localhost [127.0.0.1]) by nan.false.org (Postfix) with ESMTP id 1F012108C6; Thu, 16 Oct 2008 12:34:23 +0000 (GMT) Received: from caradoc.them.org (209.195.188.212.nauticom.net [209.195.188.212]) by nan.false.org (Postfix) with ESMTP id BDA2110009; Thu, 16 Oct 2008 12:34:22 +0000 (GMT) Received: from drow by caradoc.them.org with local (Exim 4.69) (envelope-from ) id 1KqS3a-0008UE-AX; Thu, 16 Oct 2008 08:34:22 -0400 Date: Thu, 16 Oct 2008 12:35:00 -0000 From: Daniel Jacobowitz To: Eli Zaretskii Cc: Pedro Alves , teawater@gmail.com, gdb-patches@sourceware.org, brobecker@adacore.com, msnyder@vmware.com Subject: Re: [RFA] Displaced stepping just enable in non-stop mode Message-ID: <20081016123422.GA31057@caradoc.them.org> Mail-Followup-To: Eli Zaretskii , Pedro Alves , teawater@gmail.com, gdb-patches@sourceware.org, brobecker@adacore.com, msnyder@vmware.com References: <200810160107.42525.pedro@codesourcery.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2008-05-11) 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: 2008-10/txt/msg00401.txt.bz2 On Thu, Oct 16, 2008 at 10:12:37AM +0200, Eli Zaretskii wrote: > . Why isn't it better to use displaced stepping, if supported, even > if non-stop mode is not in effect? I think the linkage between > the two is confusing and unnecessary. It is generally good to use displaced stepping. But in some circumstances it is slower, and in others it doesn't work at all. It requires we have a small scratchpad area on the target which is writeable and executable. By default we use the area at _start; this doesn't work on some simulator targets, on targets which execute code from ROM or flash memory, or during reverse debugging. Some of those cases could be fixed by adding a user knob for where to put the scratchpad, though others can't. It's linked to non-stop because for non-stop it is required. I'm not sure what else to call displaced stepping. "Step around breakpoints"? -- Daniel Jacobowitz CodeSourcery