From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 62701 invoked by alias); 26 Oct 2016 18:16:05 -0000 Mailing-List: contact gnu-gabi-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Post: List-Help: List-Subscribe: Sender: gnu-gabi-owner@sourceware.org Received: (qmail 60083 invoked by uid 89); 26 Oct 2016 18:16:04 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Checked: by ClamAV 0.99.2 on sourceware.org X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.5 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,RCVD_IN_SORBS_SPAM,SPF_PASS autolearn=no version=3.3.2 spammy=*not*, Properties, divided, risk X-Spam-Status: No, score=-1.5 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,RCVD_IN_SORBS_SPAM,SPF_PASS autolearn=no version=3.3.2 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on sourceware.org X-Spam-Level: X-HELO: mail-qk0-f182.google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=fY+1YlpEzqlQz2xlRko/EzgQJ31bSV5nOKwtaGwHZJI=; b=vEgMYhaPbwFy8iST6sPDd43b7nFXbTEAJ4MPtvbId37Zn+Gwt/PRbSfMrC1zvF7g9Q QWmdXi2DzWW2HChKCRgDSOGNcmb5y1YMHHRqDQuxQ7Eio0hRLgl5Eia1EzjlHabPPxM1 lvUAAznWtMIYJTg62w4Memw0yrN8vXDArUmkKWiqXHMp6iMe1o9974257oA8W+Yb9zrj BHp5QBh/Eilmx/7z8xflGaFH7/yBkBq1hmgM29+B0aRT7Qll4KNj9JYJTmjsUiePBxJd AtgS35o7aioobvpLgIlQcTLVosqoWwTjF2iORcI8CkVdN/0ewyK2qbpzgKRMhD/bj4L/ iwIw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=fY+1YlpEzqlQz2xlRko/EzgQJ31bSV5nOKwtaGwHZJI=; b=KUjSkwf2GAQ78f+6XRNtJNk8ONFZjvMzLYRZQJYNSd6mqNGI9XVUbFPET+RgG+L8KH eazmATsZPaJiNfkuDQxRYn3hdbU8gjlGyrfYhod1K6jr7aMCMis/6EoJ24c/lYyPu0mq soC1ookKL/PpsPwm8RoW7la6dCDJqeTEWs3x5KCcK3urEG0gRSyviVAL8aw5ZmwLD2cD Z7lpOSv1dbFZKMY7pbha4jAl2A3j/0oxNlIGgsQfC2NnfexhugrKoJ3rObxXuwb0l71y baFKU0zdBCQyRRByCg+YjnEdJRApkOsmAdkZoSLzx/PA1UP0L61WPYUl4badBTHNsoAS YpvQ== X-Gm-Message-State: ABUngvfxrn2MZWRy6y2LQSrNXTwvyEA0SYKo4a9IhLWXsFq7ZoJYGgIB82FnS1GLRzotH2JKMo3S0PLVTkvHcg== X-Received: by 10.55.18.145 with SMTP id 17mr2627400qks.34.1477505752435; Wed, 26 Oct 2016 11:15:52 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <969fb6da-f13c-eb14-3e53-94a594384518@redhat.com> From: "H.J. Lu" Date: Fri, 01 Jan 2016 00:00:00 -0000 Message-ID: Subject: Re: RFC: Program Properties To: "Maciej W. Rozycki" Cc: "Carlos O'Donell" , gnu-gabi@sourceware.org, Nick Clifton Content-Type: text/plain; charset=UTF-8 X-SW-Source: 2016-q4/txt/msg00024.txt.bz2 On Tue, Oct 25, 2016 at 4:46 AM, Maciej W. Rozycki wrote: > On Mon, 17 Oct 2016, H.J. Lu wrote: > >> > 4. A reject flag: if such annotated the ABI flag requires explicit support >> > (special handling beyond the three variants above) and linking fails if >> > it is set in any input object and the linker does know this ABI flag. >> >> "reject" isn't very clear. Is "mandatory" better? > > Such property seen by the component addressed (be it the static linker, > dynamic loader or OS kernel) would cause the binary to be rejected unless > already explicitly recognised by the component. Or IOW unknown such > properties would be rejected and known ones handled as required. Hence > the name proposed. > > That written, having thought about it some more, I think we don't > actually need such an explicit flag as I think we can reasonably set this > semantics as the default. That is any unknown property *not* annotated > with one of the known flags would be rejected, making an explicit "reject" > flag redundant. > >> > Such annotation would of course have to be consistent across input files. >> > >> > Such ABI flag flags would allow ABIs to define new ABI flags processed >> > automatically in static linking without the need to upgrade the linker >> > each time a flag is added. >> > >> > Thoughts? >> >> Property values can be divided into ranges of different rules, including >> rules which differ from above. > > I'm not sure defining fixed ranges has an advantage over using property > annotation. I think it's hard to assess beforehand how many values we may > need in each range and if we make a range allocated too narrow, then we > risk running out of entries within, whereas if we make one too broad, then We can add another property note if we run out of property types. > we risk running out of the allocation space. On the other hand by using > explicit property annotation we will only have consumed as much of the > allocation space as has actually been defined at any point in time. > > Have I missed anything? > The question is where annotation is stored. It is either stored in property type or property data. If it is encoded in type, it will limit number of usable types. It it hard to tell how many types will be needed in the future. I can't image that we need hundreds of property types in a file and we can always add a new note if needed. If it is encoded in data, it should be stored in the first few bytes, which increases data size or make run-time processing less efficient because of little endian vs big endian. We can first identify how many different annotations we need and figure out what the best way to encode them for both extensibility as well as run-time efficiency. -- H.J.