From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 13657 invoked by alias); 29 Jul 2008 15:38:41 -0000 Received: (qmail 13628 invoked by uid 22791); 29 Jul 2008 15:38:39 -0000 X-Spam-Check-By: sourceware.org Received: from main.gmane.org (HELO ciao.gmane.org) (80.91.229.2) by sourceware.org (qpsmtpd/0.31) with ESMTP; Tue, 29 Jul 2008 15:38:12 +0000 Received: from list by ciao.gmane.org with local (Exim 4.43) id 1KNrH3-0002dG-Ny for gdb@sources.redhat.com; Tue, 29 Jul 2008 15:38:06 +0000 Received: from entropy.qnx.com ([209.226.137.107]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 29 Jul 2008 15:38:05 +0000 Received: from aristovski by entropy.qnx.com with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 29 Jul 2008 15:38:05 +0000 To: gdb@sources.redhat.com From: Aleksandar Ristovski Subject: Re: PowerPC prologue analysis Date: Tue, 29 Jul 2008 15:42:00 -0000 Message-ID: References: <20080728201312.GA3911@caradoc.them.org> <20080728210800.GA7730@caradoc.them.org> <488F2040.8040202@qnx.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit User-Agent: Thunderbird 2.0.0.16 (Windows/20080708) In-Reply-To: <488F2040.8040202@qnx.com> X-IsSubscribed: yes Mailing-List: contact gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org X-SW-Source: 2008-07/txt/msg00294.txt.bz2 Aleksandar Ristovski wrote: > Daniel Jacobowitz wrote: >> On Mon, Jul 28, 2008 at 04:29:18PM -0400, Aleksandar Ristovski wrote: >>> Thanks for the link! I briefly looked at the patch and it seems to >>> address some of the things I am talking about (r30-r31 issue) but the >>> comment still reads: >>> >>> + All gpr's from saved_gpr to gpr31 are saved (except during the >>> + prologue). */ >>> >>> Is that in the ABI? I would think that if it is, then the code I am >>> looking at is not according to it (gcc issue or just me not >>> understanding powerpc assembly?). >> >> Sorry, I don't know which. >> > > There seems to be no such statement in the PowerPC ABI "all gpr's from > saved_gpr to gpr31 are saved" - non-volatile registers do not need to be > stored in this manner. For example, a function may save r29 but not r30 > and r31. However PPC prologue analysis in gdb will assume there is r31 > saved as well which will make unwind_register(r31) fail (fetch bogus > value). (Note: I am using gcc 4.2.3). > > Another assumption made in gdb code is that if multiple registers are > saved by the prologue, they will be saved in the ascending index order - > I am not sure this is a requirement stated in the ABI either. (Is it?) I > believe there could be cases where registers are saved in different > order, e.g. r30, r28, r29, etc... Hopefully this doesn't happen in > practise. > > I think your patch with gpr_mask covers the first case (not all > registers saved) but the second issue (if real issue) is still not handled. And for the reference: Daniel's patch ( http://sourceware.org/ml/gdb-patches/2007-12/msg00111.html ) does solve the problem with not all registers saved. Why is the patch not in HEAD gdb?