From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.devel Subject: Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps. Date: Fri, 30 Nov 2018 12:14:59 -0800 Organization: UCLA Computer Science Department Message-ID: References: <20181127074336.GA4705@ACM> <0ec5806a-0cc6-8b9f-6bc2-97875e36a511@cs.ucla.edu> <20181127211539.GB4705@ACM> <8c38f335-b25d-9ef6-110c-6efc4fda9d67@cs.ucla.edu> <20181127215347.GC4705@ACM> <23334086-c0a1-7b34-4234-343719618bd1@cs.ucla.edu> <20181128120443.GA4036@ACM> <20181129220552.GI12576@ACM> <9dde4ed7-8401-6022-a668-258d48bb7726@cs.ucla.edu> <20181130185503.GA16256@ACM> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Trace: blaine.gmane.org 1543608802 1059 195.159.176.226 (30 Nov 2018 20:13:22 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Fri, 30 Nov 2018 20:13:22 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.1 Cc: michael_heerdegen@web.de, Eli Zaretskii , emacs-devel@gnu.org, cpitclaudel@gmail.com, monnier@IRO.UMontreal.CA To: Alan Mackenzie Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Nov 30 21:13:18 2018 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1gSpA5-00008a-AT for ged-emacs-devel@m.gmane.org; Fri, 30 Nov 2018 21:13:17 +0100 Original-Received: from localhost ([::1]:34472 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gSpCB-00086D-Lr for ged-emacs-devel@m.gmane.org; Fri, 30 Nov 2018 15:15:27 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:56479) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gSpC3-000860-EB for emacs-devel@gnu.org; Fri, 30 Nov 2018 15:15:22 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gSpBw-0005an-3g for emacs-devel@gnu.org; Fri, 30 Nov 2018 15:15:13 -0500 Original-Received: from zimbra.cs.ucla.edu ([131.179.128.68]:34042) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gSpBp-00056u-EQ; Fri, 30 Nov 2018 15:15:05 -0500 Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 75E16160500; Fri, 30 Nov 2018 12:15:00 -0800 (PST) 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 YmGieG1kUUY7; Fri, 30 Nov 2018 12:14:59 -0800 (PST) Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id A5C2F1604F2; Fri, 30 Nov 2018 12:14:59 -0800 (PST) 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 9SpimV7NFc-H; Fri, 30 Nov 2018 12:14:59 -0800 (PST) Original-Received: from Penguin.CS.UCLA.EDU (Penguin.CS.UCLA.EDU [131.179.64.200]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id 858C316027E; Fri, 30 Nov 2018 12:14:59 -0800 (PST) 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: <20181130185503.GA16256@ACM> Content-Language: en-US X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] 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:231542 Archived-At: On 11/30/18 10:55 AM, Alan Mackenzie wrote: > There are no performance "issues". Emacs with this bug fix is minutely > slower than without it, not enough to matter. I'm afraid we'll have to disagree about that. It's not worth slowing all Emacs computations by 3.5% - 10% or whatever, merely to get more-accurate locations in byte-compiler diagnostics. That is a significant slowdown, and it's too much of a price to pay for such a small benefit. I too have played with the idea to redefine eq, for a different purpose (so that bignums behave more like fixnums), and I gave it up because of similar slowdowns. It wasn't worth the cost there either. Sometimes ideas just don't work out. > The point of the exercise is specific, not vague as you have > misformulated it. It is to print the correct source locations in > compiler warnings which are currently being output as wrong locations. > For example, read bug #9109. Bug #9109 could be fixed by a read variant that returns symbols-with-positions, by changing the byte-compiler to understand the output of this read variant, and by having the byte compiler remove position information before passing a subexpression to a macro. It could also be fixed by a read variant that returns conses-with-positions. Neither fix would slow down ordinary code. However, as I understand it, we don't want either fix because these fixes would still generate subpar locations in diagnostics when byte-compiling other code that calls macros. This is why I have been thinking about other code errors that involve macros, errors that you say are out of scope. When trying to consider alternatives to scratch/accurate-warning-pos, I was trying to get an understanding of problem scope that is independent of the proposed solution. Unfortunately I failed to do that, and this makes it difficult to consider alternatives.