From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 18680 invoked by alias); 3 Oct 2019 18:31:38 -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 18672 invoked by uid 89); 3 Oct 2019 18:31:37 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-6.1 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS autolearn=ham version=3.3.1 spammy=HContent-Transfer-Encoding:8bit X-HELO: simark.ca Received: from simark.ca (HELO simark.ca) (158.69.221.121) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Thu, 03 Oct 2019 18:31:36 +0000 Received: from [172.16.0.120] (192-222-181-218.qc.cable.ebox.net [192.222.181.218]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by simark.ca (Postfix) with ESMTPSA id CC8991E592; Thu, 3 Oct 2019 14:31:34 -0400 (EDT) Subject: Re: [PATCH v2] gdb: CTF support To: Wei-min Pan , gdb-patches@sourceware.org References: <1564530195-27659-1-git-send-email-weimin.pan@oracle.com> <5377c457-52b0-583d-15b5-47024eae1f48@simark.ca> <895f47d4-3e01-4d5a-474b-43dd2dd037b4@oracle.com> <0fe82814-46b8-79c2-6a25-5f5d51b158e1@simark.ca> <1055d18f-9e5c-3344-114a-3777876c9c63@oracle.com> <3a67839f-73d0-06ed-4140-073306fc618d@simark.ca> <75851ff5-771d-16fb-0a74-661c9e0722d3@simark.ca> From: Simon Marchi Message-ID: <93caabd4-f25d-61e3-a11d-52bcd8fbe3b6@simark.ca> Date: Thu, 03 Oct 2019 18:31:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-SW-Source: 2019-10/txt/msg00124.txt.bz2 On 2019-10-03 2:21 p.m., Wei-min Pan wrote: > > Let's use an example (checking omitted): > > We're replacing: >   name = ctf_type_aname_raw (fp, tid); >   TYPE_NAME (type) = obstack_strdup (&of->objfile_obstack, name); >   free (name); > > with >   gdb::unique_xmalloc_ptr name (ctf_type_aname_raw (fp, tid)); >   TYPE_NAME (type) = obstack_strdup (&of->objfile_obstack, name.get ()); > > The allocated copy from ctf_type_aname_raw is not freed. Or did I miss something? > > Weimin Yes, the second snippet frees the copy returned by ctf_type_aname_raw. It might just be that you are not familiar with the concept of std::unique_ptr in C++: https://en.cppreference.com/w/cpp/memory/unique_ptr It's a wrapper around a simple pointer that automatically calls a deleter function when it goes out of scope. gdb::unique_xmalloc_ptr is a specialization of std::unique_ptr that uses xfree as the deleter function. Here's a similar use: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=blob;f=gdb/fbsd-tdep.c;h=9422e3c1a7e1a65c76b088f42bb5986bd13a089f;hb=HEAD#l1530 `fbsd_core_vnode_path` return a pointer to an allocated C String, which `cwd` wraps. When it goes out of scope, `cwd` automatically calls `xfree` with the pointer. Simon