From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 24539 invoked by alias); 25 Jul 2005 17:58:38 -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 24527 invoked by uid 22791); 25 Jul 2005 17:58:33 -0000 Received: from palrel11.hp.com (HELO palrel11.hp.com) (156.153.255.246) by sourceware.org (qpsmtpd/0.30-dev) with ESMTP; Mon, 25 Jul 2005 17:58:33 +0000 Received: from cllmail.cup.hp.com (cllmail.cup.hp.com [15.244.92.83]) by palrel11.hp.com (Postfix) with ESMTP id 45FEE3C2F; Mon, 25 Jul 2005 10:58:31 -0700 (PDT) Received: from [15.244.95.35] (powerbook.americas.hpqcorp.net [15.244.95.35]) by cllmail.cup.hp.com (8.9.3 (PHNE_29774)/8.9.3 SMKit7.04) with ESMTP id KAA13292; Mon, 25 Jul 2005 10:58:31 -0700 (PDT) In-Reply-To: <20050725173545.GA11163@nevyn.them.org> References: <20050705195104.GA1584@ns1.xcllnt.net> <20050715000144.GB21620@nevyn.them.org> <2845064d598c2c3d2433909ea136f830@cup.hp.com> <20050715021634.GA27723@nevyn.them.org> <81d1f4d6faa9a09741ad6d68f3c1e5a9@cup.hp.com> <20050724212649.GA13210@nevyn.them.org> <20050725173545.GA11163@nevyn.them.org> Mime-Version: 1.0 (Apple Message framework v622) Content-Type: text/plain; charset=US-ASCII; format=flowed Message-Id: <03c60378b24ce0cdffee57bd8f06c9d2@cup.hp.com> Content-Transfer-Encoding: 7bit Cc: gdb-patches@sources.redhat.com From: Marcel Moolenaar Subject: Re: [PATCH] New port: ia64-*-freebsd Date: Mon, 25 Jul 2005 17:58:00 -0000 To: Daniel Jacobowitz X-SW-Source: 2005-07/txt/msg00191.txt.bz2 On Jul 25, 2005, at 10:35 AM, Daniel Jacobowitz wrote: > On Mon, Jul 25, 2005 at 10:32:27AM -0700, Marcel Moolenaar wrote: >>> That's where I get confused. How is >>> the data in the core file mapped onto the memory space? >> >> I'm not quite sure I get your drift. Let me just answer what I think >> you mean: >> >> The backing store is nothing more than a second stack. The first being >> the well-known memory stack onto which (stacked) local variables live. >> The backing store grows upwards and the memory stack grows downwards. >> So, in essence, it's a mmap'd region. Either created by the kernel >> when >> the process is created, or created by the threading implementation. >> In the core file the backing store is part of some loadable segment. >> Either by itself or part of a larger block of memory. > > No, that's not what I mean. > > Here and further below you think I'm talking about the concept of the > target object. I'm not. I'm talking specifically about the corefile > implementation you included. > > That implementation reads from an address in memory to find the > registers. If there's no room for them in memory, where the heck are > they, and how can you find them by reading from memory? They're lost. If the core file is created because the process ran out of backing store, then you're pretty much hosed. There's no way you can get a stack trace because the stacked registers you'll need first are the dirty ones and those aren't in the core file. This is the fundamental problem that Linux has. >>> I really recommend fixing your notes first and not making GDB support >>> this scheme. >> >> I've thought about it. The point is that GDB already needs to support >> it >> for Linux, so splitting up the work in such a way that FreeBSD >> temporarily >> has the same "limitations" as Linux seemed ideal. Not only is it >> possible >> to improve the overall core file support in FreeBSD, it also allows >> Linux >> to move away from the abstraction. In that sense, the abstraction is >> gradually moved out of GDB. And as for any interim solution: there is >> bound >> to be some icky code for a while. > > So the answer to my above question is "you can't yet"? Correct. >> All I can say is that I'll think about it: The FreeBSD release >> schedule >> is >> now in my advantage, but getting binutils to grok a whole new kind of >> core >> notes may by itself turn out to be... euh... challenging... :-) > > Actually it's quite easy. Challenge extended... ... Challenge accepted :-) "I'll be back" -- A. Schwarzenegger -- Marcel Moolenaar USPA: A-39004 marcel@xcllnt.net