From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 31818 invoked by alias); 19 Jul 2011 17:04:35 -0000 Received: (qmail 31810 invoked by uid 22791); 19 Jul 2011 17:04:34 -0000 X-SWARE-Spam-Status: No, hits=-7.1 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,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; Tue, 19 Jul 2011 17:04:16 +0000 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p6JH4D1K012257 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Tue, 19 Jul 2011 13:04:13 -0400 Received: from tyan-ft48-01.lab.bos.redhat.com (tyan-ft48-01.lab.bos.redhat.com [10.16.42.4]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id p6JH4C6U006352 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Tue, 19 Jul 2011 13:04:13 -0400 Received: from tyan-ft48-01.lab.bos.redhat.com (localhost.localdomain [127.0.0.1]) by tyan-ft48-01.lab.bos.redhat.com (8.14.4/8.14.4) with ESMTP id p6JH4CaN027705; Tue, 19 Jul 2011 19:04:12 +0200 Received: (from jakub@localhost) by tyan-ft48-01.lab.bos.redhat.com (8.14.4/8.14.4/Submit) id p6JH4Cak027703; Tue, 19 Jul 2011 19:04:12 +0200 Date: Tue, 19 Jul 2011 17:22:00 -0000 From: Jakub Jelinek To: Eli Zaretskii Cc: jan.kratochvil@redhat.com, gdb-patches@sourceware.org Subject: Re: [RFC 06/12] entryval: Display @entry parameters in bt full Message-ID: <20110719170411.GF2687@tyan-ft48-01.lab.bos.redhat.com> Reply-To: Jakub Jelinek References: <20110718201852.GG30496@host1.jankratochvil.net> <20110719103055.GA21344@host1.jankratochvil.net> <20110719114148.GA14146@sunsite.ms.mff.cuni.cz> <83d3h66x9q.fsf@gnu.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <83d3h66x9q.fsf@gnu.org> User-Agent: Mutt/1.5.21 (2010-09-15) 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: 2011-07/txt/msg00480.txt.bz2 On Tue, Jul 19, 2011 at 07:38:41PM +0300, Eli Zaretskii wrote: > > 4) only current value is known, entry value isn't provided (the value > > passed to the function in the caller wasn't saved in any call saved > > register or memory slot and wasn't constant, or the compiler didn't > > provide call site info for it) > > Show "optimized out" in calls and backtraces, the current value in > response to "print foo". This is IMHO a bad idea, the current value is still far better than "optimized out", at least when it is obvious from the backtrace which one is which. All -O0 compiled code would show just "optimized out" in backtraces for all arguments, similarly all code compiled by older compilers. And, even for -O2 -g code the entry value will be available in roughly 50% of cases at most. The lack of entry value being provided doesn't mean that the current value isn't the same as the value on entry, just that it wasn't proved. Jakub