From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 30172 invoked by alias); 9 Apr 2002 18:52:18 -0000 Mailing-List: contact gdb-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sources.redhat.com Received: (qmail 30062 invoked from network); 9 Apr 2002 18:52:14 -0000 Received: from unknown (HELO localhost.redhat.com) (216.138.202.10) by sources.redhat.com with SMTP; 9 Apr 2002 18:52:14 -0000 Received: from cygnus.com (localhost [127.0.0.1]) by localhost.redhat.com (Postfix) with ESMTP id C04B33CC2; Tue, 9 Apr 2002 14:52:15 -0400 (EDT) Message-ID: <3CB3385F.10209@cygnus.com> Date: Tue, 09 Apr 2002 11:52:00 -0000 From: Andrew Cagney User-Agent: Mozilla/5.0 (X11; U; NetBSD macppc; en-US; rv:0.9.9) Gecko/20020328 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Daniel Berlin Cc: gdb@sources.redhat.com Subject: Re: think-o: dwarf2 CFA != frame->frame (x86-64) References: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-SW-Source: 2002-04/txt/msg00139.txt.bz2 > So you can't say that it should use DW_AT_frame_base. It can't. >> > DW_AT_frame_base is a completely different concept. It is not intended to >> > have anything to do with unwinding the stack. It also has nothing >> > necessarily to do with a real frame base. See 3.3.5. This is why it's in >> > quotes. Most compiler use it in way 1 described in that section, to >> > simplify location descriptions. > >> >> (Didn't I point you at 3.3.5? :-). >> >> Location expressions use DW_OP_fbreg when they need to refer to the >> stack. DW_OP_fpreg is defined in terms of DW_AT_frame_base. Can you >> please point me to the section where a location expression OP directly >> (not indirectly as in a register) refers to the CFA? > > > No, why would I need to? > For all intents and purposes, you could severe the CFA sections of the > dwarf2 spec, and place them into something called "the CFA spec". > It doesn't change the fact that frame->base with CFA info can't use > DW_AT_frame_base. There are two concepts here (frame_base and CFA). GDB's frame->frame can only correspond to one. My point is that GDB's concept of a frame->frame best fits DW_AT_frame_base (the high level language frame pointer) and not CFA (something for reverse engineering register locations). Perhaphs GDB's concept is wrong. Given it is for debugging high level languages I don't think so. Andrew