From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 19277 invoked by alias); 17 Jan 2009 18:56:41 -0000 Received: (qmail 19268 invoked by uid 22791); 17 Jan 2009 18:56:39 -0000 X-SWARE-Spam-Status: No, hits=-1.9 required=5.0 tests=AWL,BAYES_00,SARE_MSGID_LONG40,SPF_PASS X-Spam-Check-By: sourceware.org Received: from smtp-out.google.com (HELO smtp-out.google.com) (216.239.33.17) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Sat, 17 Jan 2009 18:56:35 +0000 Received: from spaceape9.eur.corp.google.com (spaceape9.eur.corp.google.com [172.28.16.143]) by smtp-out.google.com with ESMTP id n0HIuW7I018889 for ; Sat, 17 Jan 2009 18:56:32 GMT Received: from rv-out-0708.google.com (rvbk29.prod.google.com [10.140.87.29]) by spaceape9.eur.corp.google.com with ESMTP id n0HIuTnO009242 for ; Sat, 17 Jan 2009 10:56:29 -0800 Received: by rv-out-0708.google.com with SMTP id k29so2364187rvb.30 for ; Sat, 17 Jan 2009 10:56:28 -0800 (PST) MIME-Version: 1.0 Received: by 10.140.225.19 with SMTP id x19mr1910938rvg.121.1232218588131; Sat, 17 Jan 2009 10:56:28 -0800 (PST) In-Reply-To: <20090117033152.GM24105@adacore.com> References: <20081106210721.392FF1C799C@localhost> <20090117033152.GM24105@adacore.com> Date: Sat, 17 Jan 2009 18:56:00 -0000 Message-ID: Subject: Re: [RFC] Support for comdat-based dwarf debug info reduction for types. From: Doug Evans To: Joel Brobecker Cc: gdb-patches@sourceware.org, Cary Coutant Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit 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: 2009-01/txt/msg00402.txt.bz2 On Fri, Jan 16, 2009 at 7:31 PM, Joel Brobecker wrote: > Doug, > >> Hi. Here is my current patch to support comdat-based dwarf debug info >> reduction for types. >> >> http://wiki.dwarfstd.org/index.php?title=COMDAT_Type_Sections > > I don't remember anyone answering your email. That's too bad, because > I think that any attempt at reducing the size of debugging info is > interesting. > >> I'm hoping someone can find some to give me a review. >> The patch can't go in today as the corresponding GCC support isn't >> in the main trunk yet. > > Regarding timing, I don't think we have to wait for GCC. As far as I can > tell, this would add a functionality without disturbing the current > behavior, right? Or perhaps the problem is actual testing of your code? Correct, it adds functionality without disturbing current behaviour. [if there is a disturbance, that's a bug] The patch has been well tested with and without the corresponding gcc patch of Cary's. No claim is made that it couldn't use more testing of course. :-) IIRC, there is one known bug, tracking of the source file a type came from; I plan to fix that before the gdb release with the patch goes out of course. Depending on the relative timings of gdb/gcc tree status and releases, we may want to get the gdb support in sooner rather than later (so gdb releases support the feature when it is in gcc). One reason for waiting might be that some other compiler might implement the current proposal, and then the dwarf spec changes and gdb has to support the old version. The proposal only has a few remaining minor issues, and I think the probability of anything like this happening is remote; I offer it for completeness' sake. > Speaking of GCC, do you know the status of the enhancement? We're waiting on gcc to enter stage1. The patch is ready, modulo AIUI it hasn't been reviewed yet, and modulo I don't know how much gcc has changed since the patch was last tested. >> This patch is incomplete in that the proposal has moved the ODR signature >> from the CU header to an attribute. >> This is a trivial change, relative to the entire patch. > > Do you have an updated version of your patch. I've mostyl been hacking > the dwarf2 reader, so hopefully someone more veteran can review the > code eventually, but my comments will (hopefully!) be better than > nothing :). I will resubmit a patch against current CVS head next week. The patch is currently in the archer-dje-dwarf-sig8 archer branch. Thanks.