From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 17845 invoked by alias); 26 May 2005 15:08:48 -0000 Mailing-List: contact gdb-patches-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sources.redhat.com Received: (qmail 17835 invoked by uid 22791); 26 May 2005 15:08:43 -0000 Received: from nevyn.them.org (HELO nevyn.them.org) (66.93.172.17) by sourceware.org (qpsmtpd/0.30-dev) with ESMTP; Thu, 26 May 2005 15:08:43 +0000 Received: from drow by nevyn.them.org with local (Exim 4.50) id 1DbJyU-0002Ze-07; Thu, 26 May 2005 11:08:42 -0400 Date: Thu, 26 May 2005 20:40:00 -0000 From: Daniel Jacobowitz To: Orjan Friberg Cc: gdb-patches@sources.redhat.com Subject: Re: Dwarf-2 unwinding vs. manual prologue analysis Message-ID: <20050526150841.GA9804@nevyn.them.org> Mail-Followup-To: Orjan Friberg , gdb-patches@sources.redhat.com References: <4295E439.7070104@axis.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4295E439.7070104@axis.com> User-Agent: Mutt/1.5.8i X-SW-Source: 2005-05/txt/msg00559.txt.bz2 Please use gdb@ for questions; I expect most messages to gdb-patches to be in need of review :-) On Thu, May 26, 2005 at 04:59:05PM +0200, Orjan Friberg wrote: > When adding the CRISv32 support, it seemed like a good idea to avoid having > to do manual prologue analysis to determine where registers are saved, > figuring out the return address etc. For some reason I imagined I wouldn't > have to do this if I could use the Dwarf-2 frame sniffer (because all code > would have Dwarf-2 CFI). I hooked in the Dwarf-2 frame sniffer and > everything ran fine, and it wasn't until just recently that I discovered > (to my horror) that the prologue scanner (meant for CRISv10 only; the ISAs > are not compatible) was not only called when debugging CRISv32, but simple > things like 'next' broke in various places in the testsuite when I didn't > do it. > > I do feel a bit embarrased asking this, as one would think I'd know this > already. Since I obviously don't, here we go: > > Do I need to able to do manual prologue analysis when there's Dwarf-2 CFI > available? If so, is there a set of minimum requirements for what that > analysis must be able figure out? No. If enabling the DWARF-2 CFI support causes things to break, then you need to inspect your CFI; it is probably broken. You need to do prologue analysis if there's anything without CFI that you need to handle, which there usually is - for instance PLT stubs. -- Daniel Jacobowitz CodeSourcery, LLC