From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 14570 invoked by alias); 6 Aug 2010 16:59:46 -0000 Received: (qmail 14558 invoked by uid 22791); 6 Aug 2010 16:59:45 -0000 X-Spam-Check-By: sourceware.org Received: from aquarius.hirmke.de (HELO calimero.vinschen.de) (217.91.18.234) by sourceware.org (qpsmtpd/0.83/v0.83-20-g38e4449) with ESMTP; Fri, 06 Aug 2010 16:59:41 +0000 Received: by calimero.vinschen.de (Postfix, from userid 500) id 9023D6D4171; Fri, 6 Aug 2010 18:59:36 +0200 (CEST) Date: Fri, 06 Aug 2010 16:59:00 -0000 From: Corinna Vinschen To: gdb-patches@sourceware.org Subject: Re: [rfa] frame address size incorrect if address size != ptr size Message-ID: <20100806165936.GF31783@calimero.vinschen.de> Reply-To: gdb-patches@sourceware.org Mail-Followup-To: gdb-patches@sourceware.org References: <20100806155738.GA2815@calimero.vinschen.de> <201008061627.o76GRVra002284@d12av02.megacenter.de.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <201008061627.o76GRVra002284@d12av02.megacenter.de.ibm.com> User-Agent: Mutt/1.5.20 (2009-06-14) X-IsSubscribed: yes 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: 2010-08/txt/msg00076.txt.bz2 On Aug 6 18:27, Ulrich Weigand wrote: > Corinna Vinschen wrote: > > The problem for XStormy16 in 16 bit pointer mode is that a pointer is > > not able to point to every place in the 24 bit address space the CPU can > > address. For function pointers that means that the target potentially > > has to use a jump table. For the stack that means it is restricted to > > the first 64K RAM. > > > > So, afaics, the unwind-pe.h code only works correct for XStormy16, if > > either the application fits into the first 64K of memory, or if > > DW_EH_PE_absptr is not used, rather DW_EH_PE_pcrel, DW_EH_PE_textrel, > > DW_EH_PE_datarel, or DW_EH_PE_funcrel. Oh, and then there's the > > type of _Unwind_Ptr, which would have to be big enough, 32 bit. > > OK, I see what you mean. So if we were to enable DWARF EH for XStormy16, > we'd either have to do what you just described (all of which should in > principle be doable), or else add something new to support larger "pointer" > or address types. I'd assume this might then be a new encoding type ... > > In any case, I'd still say that GDB today ought to match what GCC today > does, which is that DW_EH_PE_absptr encoding uses target-format pointers. > If and when GCC is extended, say to support another encoding type, we'd > then likewise extend GDB to support that new feature. > > > > > I'd reword this to make clear that this value is *not* used for .eh_frame, > > > but solely for .debug_frame. > > > > Ok, will do. I'd just like to put the discussion to an end, first. > > Just tell me what you think of what I wrote above. > > Does the above make sense to you? Yes, fine with me, but that also means the comment I added makes still sense... Corinna -- Corinna Vinschen Cygwin Project Co-Leader Red Hat