From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 29964 invoked by alias); 23 Apr 2008 09:50:07 -0000 Received: (qmail 29941 invoked by uid 22791); 23 Apr 2008 09:50:05 -0000 X-Spam-Check-By: sourceware.org Received: from mail.codesourcery.com (HELO mail.codesourcery.com) (65.74.133.4) by sourceware.org (qpsmtpd/0.31) with ESMTP; Wed, 23 Apr 2008 09:49:46 +0000 Received: (qmail 8749 invoked from network); 23 Apr 2008 09:49:42 -0000 Received: from unknown (HELO localhost) (vladimir@127.0.0.2) by mail.codesourcery.com with ESMTPA; 23 Apr 2008 09:49:42 -0000 From: Vladimir Prus To: Nick Roberts , gdb-patches@sourceware.org Subject: Re: [PATCH] -stack-info-frame/-stack-list-frames Date: Wed, 23 Apr 2008 10:32:00 -0000 User-Agent: KMail/1.9.6 (enterprise 0.20070907.709405) References: <18446.45778.889114.789630@kahikatea.snap.net.nz> <200804230933.04964.vladimir@codesourcery.com> <18446.63716.779534.2827@kahikatea.snap.net.nz> In-Reply-To: <18446.63716.779534.2827@kahikatea.snap.net.nz> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200804231349.35190.vladimir@codesourcery.com> 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: 2008-04/txt/msg00507.txt.bz2 On Wednesday 23 April 2008 12:52:52 you wrote: > > > The frame address is probably of more interest than the pc address, at > > > least for frames other than the current one. If the call stack includes > > > the frame address for each frame and the watch window gives the variable's > > > address then it is possible to infer to which frame that variable belongs. > > > > What do you mean by "watch window" here, and how the information about frame > > a variable belongs to is useful? > > I mean the window showing a variable's value (represented in Gdb as a variable > object). Does that window shows: 1. Value of variable named XXX in the frame where that variable was added to the window? 2. Value of variable named XXX in the current frame 3. Something else? > > > > In any case, the extra field comes at almost no cost and a frontend can > > > choose to ignore it. > > > > I supposed you don't plan to write documentation that say "these fields are > > just in case you need them, feel free to ignore"? > > Not really because that applies equally to all the other fields, already > present, that a front end might not use. Well, for other frames I know what they are used for. > > I'm trying to understand > > what is *your* intended use of this information, so that I can make up my > > mind as to best way to do that. We talked about frame ids before, I think > > Dan prefers frame ids, if exposed, to be totally opaque. You appear to > > suggest some smart uses of frame addresses, on the other hand, and I don't > > understand exactly what uses. > > I'm just intending to present the frame address to the user to help him > understand what he's looking at, not use it as a frame id in any rigorous way. > I see that the Totalview debugger presents this information in their call stack > (which they call stack trace) window and I think this would be useful, for the > reason, I've given too. Well, I still fail to see what further "understanding" the user might get from that information, but I'd be happy to be told :-) My biggest worry about this is that we'll be providing some information which is highly compiler dependent and which we cannot document in any way other that "it is hex number". I don't think a random frontend author knows what DWARF CFI is :-) - Volodya