From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 58250 invoked by alias); 28 Jun 2017 14:39:32 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 58233 invoked by uid 89); 28 Jun 2017 14:39:32 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.4 required=5.0 tests=BAYES_00,RCVD_IN_SORBS_SPAM,RP_MATCHES_RCVD,SPF_HELO_PASS autolearn=no version=3.3.2 spammy=paint X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Wed, 28 Jun 2017 14:39:31 +0000 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E2218C04575B; Wed, 28 Jun 2017 14:39:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com E2218C04575B Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=palves@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com E2218C04575B Received: from [127.0.0.1] (ovpn04.gateway.prod.ext.ams2.redhat.com [10.39.146.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4939189E50; Wed, 28 Jun 2017 14:39:29 +0000 (UTC) Subject: Re: [PATCH 02/40] Eliminate make_cleanup_obstack_free, introduce auto_obstack To: Yao Qi References: <1496406158-12663-1-git-send-email-palves@redhat.com> <1496406158-12663-3-git-send-email-palves@redhat.com> <86lgoce6vh.fsf@gmail.com> Cc: gdb-patches@sourceware.org From: Pedro Alves Message-ID: Date: Wed, 28 Jun 2017 14:39:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <86lgoce6vh.fsf@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-SW-Source: 2017-06/txt/msg00763.txt.bz2 On 06/28/2017 11:36 AM, Yao Qi wrote: > Pedro Alves writes: > >> +/* An obstack that frees itself on scope exit. */ >> +struct auto_obstack : obstack >> +{ >> + auto_obstack () >> + { obstack_init (this); } >> + >> + ~auto_obstack () >> + { obstack_free (this, NULL); } >> + >> + /* Free all memory in the obstack but leave it valid for further >> + allocation. */ >> + void clear () >> + { obstack_free (this, obstack_base (this)); } >> +}; > > Hi Pedro, > Did you consider "upstream" this to include/obstack.h? so that gcc can > use it as well. > A little, but not very seriously. I did name the type as "auto_" thinking that that's what GCC folks tend to name their container/RAII types. But OTOH, it feel a bit too early to propose that; it feels like we could do more with extending the auto_obstack API; but OTOH I'm not sure whether we'll continue to use obstacks directly that much; I suspect that we may end up with allocators instead, thought I haven't given that that much thought. Also, I think that it couldn't be put in include/obstack.h, since the obstack API requires that you define the obstack_chunk_alloc/obstack_chunk_free macros (and GCC defines those differently from us, which would be recipe for ODR violations). Also, unfortunately GCC is still C++03, and I didn't want to paint myself into a corner. :-) Thanks, Pedro Alves