From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 13731 invoked by alias); 3 Sep 2003 20:41:43 -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 13720 invoked from network); 3 Sep 2003 20:41:42 -0000 Received: from unknown (HELO nevyn.them.org) (66.93.172.17) by sources.redhat.com with SMTP; 3 Sep 2003 20:41:42 -0000 Received: from drow by nevyn.them.org with local (Exim 4.22 #1 (Debian)) id 19ueRg-0004kS-9H; Wed, 03 Sep 2003 16:41:40 -0400 Date: Wed, 03 Sep 2003 20:41:00 -0000 From: Daniel Jacobowitz To: Richard.Earnshaw@buzzard.freeserve.co.uk Cc: gdb-patches@sources.redhat.com, Richard.Earnshaw@arm.com Subject: Re: [RFA] Repost ARM frame patches Message-ID: <20030903204139.GA9605@nevyn.them.org> Mail-Followup-To: Richard.Earnshaw@buzzard.freeserve.co.uk, gdb-patches@sources.redhat.com, Richard.Earnshaw@arm.com References: <20030829014956.GA30404@nevyn.them.org> <200309022252.h82MqQum001042@buzzard.buzzard.freeserve.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200309022252.h82MqQum001042@buzzard.buzzard.freeserve.co.uk> User-Agent: Mutt/1.5.1i X-SW-Source: 2003-09/txt/msg00024.txt.bz2 On Tue, Sep 02, 2003 at 11:52:26PM +0100, Richard Earnshaw wrote: > Daniel, > > My appologies for not reviewing this before. Just way too much day job... > > It looks fine to me (at least, it seems better than what's there at > present). > > My only question is, once we start using the dwarf2 unwinder, can it cope > with the fact that gcc currently does not emit frame unwind information > for Thumb code? (ie can it handle a mix of code that uses dwarf2 and > traditional unwinding?) I was going to say yes, but... drow@nevyn:/big/fsf/projects/arm/obj/gdb/testsuite/interwork% readelf -wf test1.o The section .debug_frame contains: 00000000 0000000c ffffffff CIE Version: 1 Augmentation: "" Code alignment factor: 1 Data alignment factor: -4 Return address column: 14 DW_CFA_def_cfa: r13 ofs 0 00000010 0000000c 00000000 FDE cie=00000000 pc=00000000..0000001c 00000020 0000000c 00000000 FDE cie=00000000 pc=0000001c..00000046 i.e. GCC emits _empty_ dwarf unwind information for thumb functions, rather than none at all. That's unlikely to work. We'd need to modify the dwarf2 unwinder to ignore empty FDEs. I'll check in the non-dwarf parts now, and then we can figure out what to do about that. -- Daniel Jacobowitz MontaVista Software Debian GNU/Linux Developer