From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 6153 invoked by alias); 13 Dec 2006 21:53:10 -0000 Received: (qmail 6144 invoked by uid 22791); 13 Dec 2006 21:53:10 -0000 X-Spam-Check-By: sourceware.org Received: from smtp-vbr15.xs4all.nl (HELO smtp-vbr15.xs4all.nl) (194.109.24.35) by sourceware.org (qpsmtpd/0.31) with ESMTP; Wed, 13 Dec 2006 21:53:05 +0000 Received: from webmail.xs4all.nl (dovemail3.xs4all.nl [194.109.26.5]) by smtp-vbr15.xs4all.nl (8.13.8/8.13.8) with ESMTP id kBDLqpa2086956; Wed, 13 Dec 2006 22:52:52 +0100 (CET) (envelope-from mark.kettenis@xs4all.nl) Received: from 82.92.89.47 (SquirrelMail authenticated user sibelius) by webmail.xs4all.nl with HTTP; Wed, 13 Dec 2006 22:52:52 +0100 (CET) Message-ID: <5950.82.92.89.47.1166046772.squirrel@webmail.xs4all.nl> In-Reply-To: <20061213214540.GA28965@nevyn.them.org> References: <20061211190300.GA4372@host0.dyn.jankratochvil.net> <20061211224022.AD76E1800E7@magilla.sf.frob.com> <20061212155233.GH29911@devserv.devel.redhat.com> <20061213204603.GA11741@host0.dyn.jankratochvil.net> <20061213210357.GA27039@nevyn.them.org> <23342.82.92.89.47.1166046052.squirrel@webmail.xs4all.nl> <20061213214540.GA28965@nevyn.them.org> Date: Wed, 13 Dec 2006 21:53:00 -0000 Subject: Re: [PATCH] Re: Unwinding CFI gcc practice of assumed `same value' regs From: "Mark Kettenis" To: "Mark Kettenis" , "Jan Kratochvil" , gdb-patches@sourceware.org User-Agent: SquirrelMail/1.4.8 MIME-Version: 1.0 Content-Type: text/plain;charset=iso-8859-1 Content-Transfer-Encoding: 8bit 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: 2006-12/txt/msg00182.txt.bz2 > On Wed, Dec 13, 2006 at 10:40:52PM +0100, Mark Kettenis wrote: > > It's a perfectly reasonable thing for the libgcc unwinder to do (just > > as it is for us in GDB). But in a debugger I want to see that PC == 0 > > if it is an abnormal backtrace termination. > > > > What really needs to be done is making the DWARF2 unwinder recognize the > > condition and return a suitable frame id for that. > > Sorry, but I'm confused again :-( > > Do you mean making the DWARF2 unwinder decide that ra == 0 is a clean > terminator? That seems like a bad thing to do if you want to ever show > PC == 0 as abnormal termination; then it will do so only if the last > frame left on the stack didn't have DWARF2 info. Or do you mean some > other change to the unwinder? No, sorry, it is me who is confused. I didn't actually look at Jan's patch and assumed it did the the right thing of marking the return address as undefined. Mark