From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 29538 invoked by alias); 22 Sep 2006 02:59:13 -0000 Received: (qmail 29530 invoked by uid 22791); 22 Sep 2006 02:59:12 -0000 X-Spam-Check-By: sourceware.org Received: from nevyn.them.org (HELO nevyn.them.org) (66.93.172.17) by sourceware.org (qpsmtpd/0.31.1) with ESMTP; Fri, 22 Sep 2006 02:59:10 +0000 Received: from drow by nevyn.them.org with local (Exim 4.54) id 1GQbFs-0003W6-In; Thu, 21 Sep 2006 22:59:08 -0400 Date: Fri, 22 Sep 2006 02:59:00 -0000 From: Daniel Jacobowitz To: Michael Snyder Cc: GDB Patches ML Subject: Re: Infinite backtrace on (eg.) ARM Message-ID: <20060922025908.GA13241@nevyn.them.org> Mail-Followup-To: Michael Snyder , GDB Patches ML References: <1158889724.22863.41.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1158889724.22863.41.camel@localhost.localdomain> User-Agent: Mutt/1.5.13 (2006-08-11) X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2006-09/txt/msg00138.txt.bz2 On Thu, Sep 21, 2006 at 06:48:44PM -0700, Michael Snyder wrote: > So we can check for: > * doesn't save its PC, and > * frame->level > 0, and > * frame->next is not a call dummy. > > Except that the information "doesn't save its PC" isn't public > at the point where we want it. It's hidden within frame_register_unwind > and below -- in this case, in trad_frame. So we sort of have a problem > of "what do we know, and when do we know it". > > So -- what if we exported a method to make that info public? > It's rather specific, but in this case important: "does this > frame save its return address?" I think this is about the same as what I did in the third URL I sent you. I used a slightly roundabout way of answering the same question, which didn't require a new interface: if we can tell that the frame is deferring the question "where's my PC" to the next frame, then it couldn't have saved the PC itself. The second patch had some points of disagreement, but I think Mark and I more or less agreed on the first one before I ran out of time to work on it (I'll be back real soon, hopefully next week, to those), and the third could probably be gotten into acceptable shape readily once the first is in. -- Daniel Jacobowitz CodeSourcery