220 19897 article Path: news.gmane.org!not-for-mail From: "dgutson ." Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: First working prototype for static allocation: we can have complex containers in ROM Date: Tue, 18 Aug 2015 13:51:05 -0300 Lines: 71 Approved: news@gmane.org Message-ID: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Trace: ger.gmane.org 1439916671 16222 80.91.229.3 (18 Aug 2015 16:51:11 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 18 Aug 2015 16:51:11 +0000 (UTC) To: std-proposals , andrewtomazos@gmail.com Original-X-From: std-proposals+bncBDE3NBMV6UFBB6OEZWXAKGQEYE7DRLA@isocpp.org Tue Aug 18 18:51:10 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-qk0-f200.google.com ([209.85.220.200]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZRk6N-0002u2-9E for gclcip-std-proposals@m.gmane.org; Tue, 18 Aug 2015 18:51:07 +0200 Original-Received: by qkfn3 with SMTP id n3sf246819510qkf.3 for ; Tue, 18 Aug 2015 09:51:06 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:date:message-id:subject:from:to :content-type:content-transfer-encoding:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=CxGQN9pldvJrrw7S2fjyXALsbwyLz7K6D/4Jn2cEtfI=; b=Gi5d3yJX/YGSS+8gx/SuepOHqc/ji9UDkV5ko/LU/peKCuvFEVIDTwqGrtzELseB8K LfVjaRCmRPoK1RGrKe+cTdjDqBdLgs4n1NPFrxePHVgpbUIPIDkL7k+YjW/Qe1K6iBdI 83cdgMc5cnG6o4LzqUuE0H+bgzOHzyQnOzFnFEurSstCLt9xY5lFyLSRwTk/4L85MwQO LIgd5iIj1DemwgJ/mgrq5bEis98mS9EcUyUaVC7ejUIsCfpk2hGAh/a5wiS95a9AXOtT xiAM+rMDES6M5m/ELYyHNElUXpCu7qI9xtqoy4CrIsYp4+iFXuTKHXAxQm8UOmAl56KB 4blA== X-Gm-Message-State: ALoCoQmYd8c32JsAvUm36nOF+EX54cEnWC4eMxJSGqpiZWnWIh7RxcI/qcVkpN8KoKuDAxcW2h/Q X-Received: by 10.13.203.77 with SMTP id n74mr6635156ywd.35.1439916666532; Tue, 18 Aug 2015 09:51:06 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.107.25.194 with SMTP id 185ls2014124ioz.90.gmail; Tue, 18 Aug 2015 09:51:05 -0700 (PDT) X-Received: by 10.107.10.9 with SMTP id u9mr7345618ioi.118.1439916665613; Tue, 18 Aug 2015 09:51:05 -0700 (PDT) Original-Received: from mail-ig0-x229.google.com (mail-ig0-x229.google.com. [2607:f8b0:4001:c05::229]) by mx.google.com with ESMTPS id c199si12530734ioc.129.2015.08.18.09.51.05 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 18 Aug 2015 09:51:05 -0700 (PDT) Received-SPF: pass (google.com: domain of danielgutson@gmail.com designates 2607:f8b0:4001:c05::229 as permitted sender) client-ip=2607:f8b0:4001:c05::229; Original-Received: by igxp17 with SMTP id p17so85471751igx.1 for ; Tue, 18 Aug 2015 09:51:05 -0700 (PDT) X-Received: by 10.50.64.147 with SMTP id o19mr24345571igs.15.1439916665443; Tue, 18 Aug 2015 09:51:05 -0700 (PDT) Original-Received: by 10.36.116.147 with HTTP; Tue, 18 Aug 2015 09:51:05 -0700 (PDT) X-Original-Sender: danielgutson@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of danielgutson@gmail.com designates 2607:f8b0:4001:c05::229 as permitted sender) smtp.mailfrom=danielgutson@gmail.com; dkim=pass header.i=@gmail.com; dmarc=pass (p=NONE dis=NONE) header.from=gmail.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Spam-Checked-In-Group: std-proposals@isocpp.org X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:19897 Archived-At: Hi. We are working in a custom gcc (plus a plugin) which is able to "statically allocate" memory and modify its content during constexpr constructors. We basically provide a "static_alloc(size_t n)" function for this purpos= e. With this infrastructure, we were able to write two examples: - an uppercase_static_string class that receives a C-string in its constexpr ctor, allocates a (const) char array, copies the content transforming all the characters to uppercase. The whole object is stored in the .rodata section of the binary. The access methods are a subset of the const of the std::string. - a static_sorted_array class that receives an initializer_list, allocates the content and sorts it. The resulting array also is stored in the .rodata section. We are working towards applying the same infrastructure for non-constant objects (of static storage duration) as a superior solution to allocators with pre-allocated memory pools, since the exact required memory is calculated during compile time and out-of-memory detection can cause a compilation failure. This work is mainly inspired by embedded and safety systems needs, and has relation with Andrew's "predynamic storage". As for our need, we have to provide a "static" version of some STL containers, though a deeper analysis has to be done in order to see if this infrastructure (or the "static_alloc" direction) could be applied to the current STL containers by adding new constexpr constructors (I don't think it's possible, but I didn't get into it yet). If there are people attending the forthcoming meetings interested in championship this and being a co-author, please let me know (PM) and we will provide details and the prototype (which is actively under development in order to overcome two implementation issues). We are also looking for help to implement the static containers (we will implement only the unordered_map and multiset counterparts). What is going to happen soon is: we will send some patches to gcc and I will write a technical report about this with details. Thanks, Daniel. --=20 Who=E2=80=99s got the sweetest disposition? One guess, that=E2=80=99s who? Who=E2=80=99d never, ever start an argument? Who never shows a bit of temperament? Who's never wrong but always right? Who'd never dream of starting a fight? Who get stuck with all the bad luck? --=20 ---=20 You received this message because you are subscribed to the Google Groups "= ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposa= ls/. .