From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 13066 invoked by alias); 2 Jul 2003 21:39:06 -0000 Mailing-List: contact gdb-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sources.redhat.com Received: (qmail 13052 invoked from network); 2 Jul 2003 21:39:06 -0000 Received: from unknown (HELO crack.them.org) (146.82.138.56) by sources.redhat.com with SMTP; 2 Jul 2003 21:39:06 -0000 Received: from dsl093-172-017.pit1.dsl.speakeasy.net ([66.93.172.17] helo=nevyn.them.org ident=mail) by crack.them.org with asmtp (Exim 3.12 #1 (Debian)) id 19XpKe-0002bT-00 for ; Wed, 02 Jul 2003 16:40:04 -0500 Received: from drow by nevyn.them.org with local (Exim 3.36 #1 (Debian)) id 19XpJf-0004O7-00 for ; Wed, 02 Jul 2003 17:39:03 -0400 Date: Wed, 02 Jul 2003 21:39:00 -0000 From: Daniel Jacobowitz To: gdb@sources.redhat.com Subject: Re: Dwarf unwinder problems with store.exp and preserved regs Message-ID: <20030702213903.GA16851@nevyn.them.org> Mail-Followup-To: gdb@sources.redhat.com References: <20030701214429.GA3913@nevyn.them.org> <20030702191059.GD1914@redhat.com> <20030702191907.GA26551@nevyn.them.org> <20030702213311.GA2115@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030702213311.GA2115@redhat.com> User-Agent: Mutt/1.5.1i X-SW-Source: 2003-07/txt/msg00053.txt.bz2 On Wed, Jul 02, 2003 at 02:33:11PM -0700, Richard Henderson wrote: > On Wed, Jul 02, 2003 at 03:19:07PM -0400, Daniel Jacobowitz wrote: > > So if the initial row assumes all registers are valid, we'd print out a > > value in the caller's $eax incorrectly. > > Ok, so? Except you forget that variables that are live across > that call are either (1) in call saved registers or (2) on the > stack. So I don't see that the problem will actually affect > folk debugging real programs. > > The only time you get a false positive is when the variable is > dead at the call site. And the results you get there will be > no different than when the variable is dead and the register > gets re-used /in the same function/ without location expressions > to note the exact time of death. We'll have that information someday... but I see your point. > The best argument, IMO, is that if you switch the default from > undefined to samevalue, then you'll get useful information some > of the time as opposed to none of the time. That's good enough for me. -- Daniel Jacobowitz MontaVista Software Debian GNU/Linux Developer