From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.devel Subject: Re: [Emacs-diffs] master d826037 3/3: Remove the need for temacs.in Date: Wed, 10 Apr 2019 12:31:53 -0700 Organization: UCLA Computer Science Department Message-ID: <9093e1cb-7cad-14df-9428-6229313e8f51@cs.ucla.edu> References: <20190409224339.20116.87667@vcs0.savannah.gnu.org> <20190409224342.0DA1F20E54@vcs0.savannah.gnu.org> <86697de6baf024290a9d0b10743ba2b7.squirrel@dancol.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="77045"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 Cc: emacs-devel@gnu.org To: Daniel Colascione Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Wed Apr 10 21:34:18 2019 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1hEIz6-000Jmb-89 for ged-emacs-devel@m.gmane.org; Wed, 10 Apr 2019 21:34:12 +0200 Original-Received: from localhost ([127.0.0.1]:36809 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hEIz5-0007oz-65 for ged-emacs-devel@m.gmane.org; Wed, 10 Apr 2019 15:34:11 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:54144) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hEIwy-00077Q-Nr for emacs-devel@gnu.org; Wed, 10 Apr 2019 15:32:01 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hEIww-0006qh-Rz for emacs-devel@gnu.org; Wed, 10 Apr 2019 15:32:00 -0400 Original-Received: from zimbra.cs.ucla.edu ([131.179.128.68]:37656) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hEIwv-0006p7-57 for emacs-devel@gnu.org; Wed, 10 Apr 2019 15:31:58 -0400 Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id D06C61612CF; Wed, 10 Apr 2019 12:31:54 -0700 (PDT) Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id x74po1v72Cop; Wed, 10 Apr 2019 12:31:54 -0700 (PDT) Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 1A22916169F; Wed, 10 Apr 2019 12:31:54 -0700 (PDT) X-Virus-Scanned: amavisd-new at zimbra.cs.ucla.edu Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id 360hEpPhjhkj; Wed, 10 Apr 2019 12:31:54 -0700 (PDT) Original-Received: from Penguin.CS.UCLA.EDU (Penguin.CS.UCLA.EDU [131.179.64.200]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id 007971612CF; Wed, 10 Apr 2019 12:31:53 -0700 (PDT) Openpgp: preference=signencrypt Autocrypt: addr=eggert@cs.ucla.edu; prefer-encrypt=mutual; keydata= xsFNBEyAcmQBEADAAyH2xoTu7ppG5D3a8FMZEon74dCvc4+q1XA2J2tBy2pwaTqfhpxxdGA9 Jj50UJ3PD4bSUEgN8tLZ0san47l5XTAFLi2456ciSl5m8sKaHlGdt9XmAAtmXqeZVIYX/UFS 96fDzf4xhEmm/y7LbYEPQdUdxu47xA5KhTYp5bltF3WYDz1Ygd7gx07Auwp7iw7eNvnoDTAl KAl8KYDZzbDNCQGEbpY3efZIvPdeI+FWQN4W+kghy+P6au6PrIIhYraeua7XDdb2LS1en3Ss mE3QjqfRqI/A2ue8JMwsvXe/WK38Ezs6x74iTaqI3AFH6ilAhDqpMnd/msSESNFt76DiO1ZK QMr9amVPknjfPmJISqdhgB1DlEdw34sROf6V8mZw0xfqT6PKE46LcFefzs0kbg4GORf8vjG2 Sf1tk5eU8MBiyN/bZ03bKNjNYMpODDQQwuP84kYLkX2wBxxMAhBxwbDVZudzxDZJ1C2VXujC OJVxq2kljBM9ETYuUGqd75AW2LXrLw6+MuIsHFAYAgRr7+KcwDgBAfwhPBYX34nSSiHlmLC+ KaHLeCLF5ZI2vKm3HEeCTtlOg7xZEONgwzL+fdKo+D6SoC8RRxJKs8a3sVfI4t6CnrQzvJbB n6gxdgCu5i29J1QCYrCYvql2UyFPAK+do99/1jOXT4m2836j1wARAQABzSBQYXVsIEVnZ2Vy dCA8ZWdnZXJ0QGNzLnVjbGEuZWR1PsLBfgQTAQIAKAUCTIByZAIbAwUJEswDAAYLCQgHAwIG FQgCCQoLBBYCAwECH In-Reply-To: <86697de6baf024290a9d0b10743ba2b7.squirrel@dancol.org> Content-Language: en-US X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 131.179.128.68 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:235246 Archived-At: On 4/10/19 11:53 AM, Daniel Colascione wrote: > Computing a fingerprint over temacs.in factors link > layout information into the fingerprint hash. Your approach doesn't. It's > possible to link Emacs in different ways from the same object files and > produce different binaries. Computing a fingerprint over temacs.in also omitted layout information. This was particularly true when building position-independent executables. But even for the non-PIE case the fingerprint did not cover dynamically-linked libraries. In practice the omitted layout information didn't matter for temacs.in, as it was not significant for what the fingerprint is used for. Similarly, the information that the new approach omits from temacs is not significant for the fingerprint's intended use, hence we haven't lost anything significant by switching to the simpler-and-faster mechanism.