From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 129959 invoked by alias); 25 Jul 2016 11:04:31 -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 129945 invoked by uid 89); 25 Jul 2016 11:04:30 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-3.2 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD,SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=Hx-languages-length:1731, H*F:U*palves 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 (AES256-GCM-SHA384 encrypted) ESMTPS; Mon, 25 Jul 2016 11:04:19 +0000 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id AE54285540; Mon, 25 Jul 2016 11:04:18 +0000 (UTC) Received: from [127.0.0.1] (ovpn01.gateway.prod.ext.ams2.redhat.com [10.39.146.11]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u6PB4Hf5018638; Mon, 25 Jul 2016 07:04:17 -0400 Subject: Re: [RFA] PR python/18565 - make Frame.function work for inline frames To: Yao Qi , Tom Tromey References: <1466439050-11330-1-git-send-email-tom@tromey.com> <86ziqfq6sz.fsf@gmail.com> <8737o5kqtv.fsf@tromey.com> Cc: "gdb-patches@sourceware.org" From: Pedro Alves Message-ID: Date: Mon, 25 Jul 2016 11:04:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-SW-Source: 2016-07/txt/msg00323.txt.bz2 On 07/25/2016 11:23 AM, Yao Qi wrote: > Sorry, I missed this mail, > > On Wed, Jun 22, 2016 at 7:42 PM, Tom Tromey wrote: >>>>>>> "Yao" == Yao Qi writes: >> >> Yao> Tom Tromey writes: >>>> TRY >>>> { >>>> + char *funname; >>>> + enum language funlang; >>>> + >>>> FRAPY_REQUIRE_VALID (self, frame); >>>> >>>> - sym = find_pc_function (get_frame_address_in_block (frame)); >>>> + find_frame_funname (frame, &funname, &funlang, &sym); >>>> + xfree (funname); >>>> } >>>> CATCH (except, RETURN_MASK_ALL) >>>> { >> >> Yao> Call xfree in CATCH block? Otherwise, patch is good to me. >> >> I looked at this. I think it's probably better as-is. >> My reasoning is that "funname" is initialized by the call to >> find_frame_funname and isn't otherwise used. So, putting the free where >> it appears now means that there is no gap between initialization and >> free. >> > > The reason I suggested that way is that the exception may be thrown out in > find_frame_funname after the memory is allocated for funname, so we need > xfree in CATCH, and also need xfree afterwards. I disagree. In general, I think that up until the called function does a normal return, the memory for output parameters is owned by the called function. A normal return then transfers ownership of the output parameters' memory to the caller. So I think that it's find_frame_funname that should be responsible for making sure that memory for output parameters is cleaned up on exception, or be written in a way that never throws after the memory allocation, which it may be already, but I haven't checked in detail. Thanks, Pedro Alves