From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS4713 221.184.0.0/13 X-Spam-Status: No, score=-3.9 required=3.0 tests=AWL,BAYES_00, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from neon.ruby-lang.org (neon.ruby-lang.org [221.186.184.75]) by dcvr.yhbt.net (Postfix) with ESMTP id C58CC20A1E for ; Mon, 10 Dec 2018 20:11:03 +0000 (UTC) Received: from neon.ruby-lang.org (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id 117F0120FAE; Tue, 11 Dec 2018 05:11:00 +0900 (JST) Received: from o1678916x28.outbound-mail.sendgrid.net (o1678916x28.outbound-mail.sendgrid.net [167.89.16.28]) by neon.ruby-lang.org (Postfix) with ESMTPS id 40C32120FA5 for ; Tue, 11 Dec 2018 05:10:54 +0900 (JST) Received: by filter0077p3mdw1.sendgrid.net with SMTP id filter0077p3mdw1-26232-5C0EC84A-49 2018-12-10 20:10:50.961861014 +0000 UTC m=+1357.520406895 Received: from herokuapp.com (ec2-54-166-30-52.compute-1.amazonaws.com [54.166.30.52]) by ismtpd0017p1iad2.sendgrid.net (SG) with ESMTP id h0c2_c08Saewb70TIPHKLg Mon, 10 Dec 2018 20:10:50.851 +0000 (UTC) Date: Mon, 10 Dec 2018 20:10:51 +0000 (UTC) From: tenderlove@ruby-lang.org To: ruby-core@ruby-lang.org Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 65807 X-Redmine-Project: ruby-trunk X-Redmine-Issue-Id: 15393 X-Redmine-Issue-Author: tenderlovemaking X-Redmine-Sender: tenderlovemaking X-Mailer: Redmine X-Redmine-Host: bugs.ruby-lang.org X-Redmine-Site: Ruby Issue Tracking System X-Auto-Response-Suppress: All Auto-Submitted: auto-generated X-SG-EID: ync6xU2WACa70kv/Ymy4QrNMhiuLXJG8OTL2vJD1yS5DLPmrOOZmNdNCzFMwoQuk1CyGmgDn8d1AIJ DRox1o1IhkjbXT1AK64mNdkbmM62iTW5Z0lgVFaTZVUKKlHtQwoigy+0wj4iTbLEAW6pOih8eooJV/ wJumll3TpgrgiOE91/2+Z9HD6ytdZw/M8p5POpCoC0F1yBsKA9NGElf1ew== X-ML-Name: ruby-core X-Mail-Count: 90408 Subject: [ruby-core:90408] [Ruby trunk Feature#15393] Add compilation flags to freeze Array and Hash literals X-BeenThere: ruby-core@ruby-lang.org X-Mailman-Version: 2.1.15 Precedence: list Reply-To: Ruby developers List-Id: Ruby developers List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ruby-core-bounces@ruby-lang.org Sender: "ruby-core" Issue #15393 has been updated by tenderlovemaking (Aaron Patterson). Eregon (Benoit Daloze) wrote: > One alternative idea which would achieve a similar goal is having #deep_freeze on core types, and recognizing `{ 'a' => ['b', { 'c' => 'd' }] }.deep_freeze`. > This would be more general, since it would also work for freezing non-constant/non-literal data structures. I thought about doing this with ".freeze", introducing a special instruction the same way we do for the `"string".freeze` optimization, but dealing with deoptization in the case someone monkey patches the method seems like a pain. The reason I went this direction first is that it side steps the deoptimization problem, and if we want to support a ".deep_freeze" method later we can. I imagine the implementation would be a branch where one of the branches is the same `putobject` instruction that I have in this patch. Anyway, I think the advantages of this patch are: 1. No new methods like "deep_freeze", so you can try this with existing code 2. Any code you write that works with these flags enabled will also work with them disabled (vs deep_freeze that isn't on existing Rubys) 3. This patch should be forward compatible when we figure out what "deep_freeze" solution we're going to have in the future > I would think many `[]` and `{}` are meant to be mutated, so it seems frozen Array/Hash literals them would rather be the exception than the norm (which is less clear for Strings, so I think there the magic comment makes sense). I thought the same thing, but I'm not 100% convinced. Lots of code in Rails (as well as our application at work) is merging some kind of "default hash" like: ~~~ ruby def method(some_hash) some_hash = { :defaults => 'thing' }.merge(some_hash) end ~~~ I'll try to get some numbers on this though. :D ---------------------------------------- Feature #15393: Add compilation flags to freeze Array and Hash literals https://bugs.ruby-lang.org/issues/15393#change-75557 * Author: tenderlovemaking (Aaron Patterson) * Status: Open * Priority: Normal * Assignee: * Target version: ---------------------------------------- Hi, I would like to add VM compilation options to freeze array and hash literals. For example: ~~~ ruby frozen = RubyVM::InstructionSequence.compile(<<-eocode, __FILE__, nil, 0, frozen_string_literal: true, frozen_hash_and_array_literal: true) { 'a' => ['b', { 'c' => 'd' }] } eocode puts frozen.disasm ~~~ Output is: ~~~ $ ./ruby thing.rb == disasm: #@thing.rb:0 (0,0)-(0,34)> (catch: FALSE) 0000 putobject {"a"=>["b", {"c"=>"d"}]} 0002 leave ~~~ Anything nested in the hash that can't be "frozen" will cause it to not be frozen. For example: ~~~ ruby not_frozen = RubyVM::InstructionSequence.compile(<<-eocode, __FILE__, nil, 0, frozen_string_literal: true, frozen_hash_and_array_literal: true) { 'a' => some_method } eocode puts not_frozen.disasm ~~~ Output: ~~~ $ ./ruby thing.rb == disasm: #@thing.rb:0 (0,0)-(0,24)> (catch: FALSE) 0000 putobject "a" 0002 putself 0003 opt_send_without_block , 0006 newhash 2 0008 leave ~~~ Eventually I would like to freeze array and hash literals in source code itself, but I think this is a good first step. The reason I want this feature is I think we can reduce some object allocations, and once Guilds are implemented, easily create immutable data. I've attached a patch that implements the above. (Also I think maybe "frozen_literals" would be a better name, but I don't want to imply that numbers or booleans are frozen too) Thanks! ---Files-------------------------------- 0001-Add-compile-options-for-freezing-hash-and-array-lite.patch (6.14 KB) -- https://bugs.ruby-lang.org/