From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 14768 invoked by alias); 8 Jun 2010 21:19:07 -0000 Received: (qmail 14759 invoked by uid 22791); 8 Jun 2010 21:19:06 -0000 X-SWARE-Spam-Status: No, hits=-5.8 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,SPF_HELO_PASS,T_RP_MATCHES_RCVD 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; Tue, 08 Jun 2010 21:19:02 +0000 Received: from int-mx03.intmail.prod.int.phx2.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.16]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o58LIruR029523 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Tue, 8 Jun 2010 17:18:53 -0400 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx03.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o58LIqtd003393; Tue, 8 Jun 2010 17:18:52 -0400 Received: from opsy.redhat.com (ovpn01.gateway.prod.ext.phx2.redhat.com [10.5.9.1]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id o58LIqst015236; Tue, 8 Jun 2010 17:18:52 -0400 Received: by opsy.redhat.com (Postfix, from userid 500) id DB89B3785F0; Tue, 8 Jun 2010 15:18:51 -0600 (MDT) From: Tom Tromey To: Stan Shebs Cc: "gdb\@sourceware.org" Subject: Re: [RFC] Collecting strings at tracepoints References: <4C0983C3.6000604@codesourcery.com> Reply-To: tromey@redhat.com Date: Tue, 08 Jun 2010 21:19:00 -0000 In-Reply-To: <4C0983C3.6000604@codesourcery.com> (Stan Shebs's message of "Fri, 04 Jun 2010 15:52:51 -0700") 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 gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org X-SW-Source: 2010-06/txt/msg00033.txt.bz2 >>>>> "Stan" == Stan Shebs writes: Stan> For tracepoint collection, I think the automatic heuristic is probably Stan> not a good idea. I agree. Stan> Looking at how '@' syntax works, we can extend it without disrupting Stan> expression parsing much. For instance, "str@@" could mean to Stan> deference str, and collect bytes until a 0 is seen, or the print Stan> elements limit is reached (implication is that we would have to tell Stan> the target that number). The user could exercise even finer control Stan> by supplying the limit explicitly, for instance "str@/80" to collect Stan> at most 80 chars of the string. ("str@@80" seems like it would cause Stan> ambiguity problems vs "str@@"). Wouldn't it be "*str @@ 80" (note the leading "*"). I'm not super fond of the syntax, but I think it is probably as good as anything else I'd think up :-) Stan> Under the hood, it's not yet clear if we will need additional Stan> bytecodes, but probably so. If you add additional AX bytecodes, please consider adding what is needed for DWARF location expressions at the same time: http://sourceware.org/bugzilla/show_bug.cgi?id=11662 It seems better to batch such changes. Tom