From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 1688 invoked by alias); 4 Jun 2010 21:39:21 -0000 Received: (qmail 1678 invoked by uid 22791); 4 Jun 2010 21:39:20 -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; Fri, 04 Jun 2010 21:39:11 +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 o54LdAd7014150 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 4 Jun 2010 17:39:10 -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 o54Ld9Px002088; Fri, 4 Jun 2010 17:39:09 -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 o54Ld64R005543; Fri, 4 Jun 2010 17:39:07 -0400 Received: by opsy.redhat.com (Postfix, from userid 500) id B425637897F; Fri, 4 Jun 2010 15:39:06 -0600 (MDT) From: Tom Tromey To: Jan Kratochvil Cc: gdb-patches@sourceware.org Subject: Re: RFC: partially fix empty DW_OP_piece References: <20100514223521.GA3975@host0.dyn.jankratochvil.net> <20100602185354.GA11125@host0.dyn.jankratochvil.net> <20100603174558.GA22100@host0.dyn.jankratochvil.net> <20100604191045.GA32716@host0.dyn.jankratochvil.net> Reply-To: Tom Tromey Date: Fri, 04 Jun 2010 21:39:00 -0000 In-Reply-To: <20100604191045.GA32716@host0.dyn.jankratochvil.net> (Jan Kratochvil's message of "Fri, 4 Jun 2010 21:10:45 +0200") 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-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: 2010-06/txt/msg00139.txt.bz2 >>>>> "Jan" == Jan Kratochvil writes: Jan> OK, that probably means there really must remain a way to convert Jan> `inferior dependent struct value' into an `inferior independent Jan> struct value'. Yeah, at least as far as the bounds are concerned. IMO. The current gdb model is sort of mixed. A struct value is a snapshot of some bit of state. But, when printing a value, we might refer to other state in the target. For example: struct x { char *name; }; If we have a value of that type, gdb will try to dereference the pointer when printing. But, we make no attempt to save this memory alongside the value somewhere. So, if you have a complicated debug session and then after many re-runs or whatever do "print $1", you can get weird answers. There may be some other odd cases, too. We could fix this, of course, but it isn't clear that it is worth the effort. Tom