From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: Finalizing 'inhibit-automatic-native-compilation' Date: Sat, 28 Jan 2023 12:42:08 -0500 Message-ID: References: <837cx8cey0.fsf@gnu.org> <83357vauh5.fsf@gnu.org> <837cx6a8me.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="2101"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Cc: emacs-devel@gnu.org, akrl@sdf.org, larsi@gnus.org, rlb@defaultvalue.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sat Jan 28 18:43:04 2023 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1pLpEG-0000ON-3x for ged-emacs-devel@m.gmane-mx.org; Sat, 28 Jan 2023 18:43:04 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pLpDX-00012U-1r; Sat, 28 Jan 2023 12:42:19 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pLpDV-00010h-0J for emacs-devel@gnu.org; Sat, 28 Jan 2023 12:42:17 -0500 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pLpDT-0001xj-2R; Sat, 28 Jan 2023 12:42:16 -0500 Original-Received: from pmg1.iro.umontreal.ca (localhost.localdomain [127.0.0.1]) by pmg1.iro.umontreal.ca (Proxmox) with ESMTP id 6D1BE1000D0; Sat, 28 Jan 2023 12:42:12 -0500 (EST) Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg1.iro.umontreal.ca (Proxmox) with ESMTP id 996D81000C3; Sat, 28 Jan 2023 12:42:10 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1674927730; bh=yEinMG5IsxmbtHHZITLWCwr14uZ/Wuufgc9t8uz4re0=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=dX6NyNiyKvUcoVSokRW8jHuhQhpXtff917OoG12vowDvBeyYq9uEQXPe7EagVG25G uas8/pHgexha29pV4UYF728WSkC9AX87jBK/BfhEGwdFUf87OWwhSajh8iK8nUmfRY yXgAvEH+phlCdip1AWzyVi/UUR/0N9gH9fRBRo8eB24vgv/afwNG8CJqegS2RJgUyI Hmn/ro2x2SMlucGRjFDKxwMJAhNq/+lfpteq3SGDC5b1s0LX3Ov41/9Eb95lcGXYDx aukk4GflMF4XtTqBevkjli9cV8+fapJD3CjIBo5HSiwUrieTmet42sTGYB+ib+zzRF cJyvFwN0s9xRg== Original-Received: from pastel (unknown [45.72.216.69]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id 5F6F1122525; Sat, 28 Jan 2023 12:42:10 -0500 (EST) In-Reply-To: <837cx6a8me.fsf@gnu.org> (Eli Zaretskii's message of "Sat, 28 Jan 2023 19:09:45 +0200") Received-SPF: pass client-ip=132.204.25.50; envelope-from=monnier@iro.umontreal.ca; helo=mailscanner.iro.umontreal.ca X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 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-mx.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:302724 Archived-At: >> >> For trampolines, in the short term we should probably add a fallback to >> >> use an eln-cache in the `temporary-file-directory` (i.e. use the code >> >> we currently use when `inhibit-automatic-native-compilation` is non-nil). >> > >> > This have two problems: >> > >> > . it cleans up only on Posix platforms >> >> Yup. I hope it's "good enough" for our immediate needs, tho. > > Not from my POV, no. I assume using Emacs with a non-writable HOME/eln-cache directory is quite rare, and if (in addition to the that) the `temporary-file-directory` is always the same, then those trampoline files that we fail to delete won't keep accumulating ad-infinitum. So the problem is hopefully rare. And we do have a solution: pregenerate the trampolines. >> No: what I'm suggesting is to pregenerate the trampolines before we know >> if we'll need them (a bit like `make trampolines`), but to place them >> alongside the code that might need it, so there's no additional "small" >> files containing nothing but a trampoline. Instead we add tiny chunks >> of code (the trampolines) to other `.eln` files and we do it at a time >> where we know we have GCC at hand. > What do you mean by "alongside"? The code which needs trampolines is > the code which advises primitives, and that is written in C. Where > would "alongside" be in that case? We need trampolines because we call (from .eln files) some functions via (...) instead of looking at the function cell of a symbol, checking what kind of Lisp_Object it holds, etc... When an advice is installed (i.e. when the function cell of the symbol is modified), we need to update the `functionvar` so it points to a trampoline which does the dance of "looking at the function cell of a symbol, checking what kind of Lisp_Object it holds, etc...". So, we could pregenerate the trampoline and store it directly inside the subr that's originally stored in the symbol's function cell. So instead of (comp-subr-trampoline-install SUBR) having to generate the trampoline, it would find it in one of the fields of the subr struct. Stefan