From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gateway33.websitewelcome.com (gateway33.websitewelcome.com [192.185.146.21]) by sourceware.org (Postfix) with ESMTPS id DA85F3858D35 for ; Sun, 2 Aug 2020 17:52:12 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org DA85F3858D35 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=tromey.com Authentication-Results: sourceware.org; spf=fail smtp.mailfrom=tom@tromey.com Received: from cm16.websitewelcome.com (cm16.websitewelcome.com [100.42.49.19]) by gateway33.websitewelcome.com (Postfix) with ESMTP id 54F3651677 for ; Sun, 2 Aug 2020 12:52:12 -0500 (CDT) Received: from box5379.bluehost.com ([162.241.216.53]) by cmsmtp with SMTP id 2I9ckk0WdCjCV2I9ckkINY; Sun, 02 Aug 2020 12:52:12 -0500 X-Authority-Reason: nr=8 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=tromey.com; s=default; h=Content-Type:MIME-Version:Message-ID:In-Reply-To:Date: References:Subject:Cc:To:From:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=fRTJZmJwLe8xJO6ZAqA5fAd0BDdEg/lBMHDOe8vnCUA=; b=V+rUNyS5B3gGLLtu6gYpaO2tt0 oBI8agEQw3zE57tf7hELgEO+7tDBTdKprlfAWpI89I/K02XZXQTz/2xSakURdiHRRz8tQYLwVQGmU hqajA0xrYoERet9R0jm8AiggO; Received: from 174-16-104-48.hlrn.qwest.net ([174.16.104.48]:55402 helo=bapiya) by box5379.bluehost.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1k2I9b-003h0b-UJ; Sun, 02 Aug 2020 11:52:12 -0600 From: Tom Tromey To: Simon Marchi Cc: Tom Tromey , Pedro Alves , gdb-patches@sourceware.org Subject: Re: [PATCH 02/23] Don't rely on inferior_ptid in record_full_wait References: <20190906232807.6191-1-palves@redhat.com> <20190906232807.6191-3-palves@redhat.com> <87h7tope4d.fsf@tromey.com> <9d4243a6-3b43-802b-b1d6-4cd0497205af@simark.ca> <87d04ap01b.fsf@tromey.com> X-Attribution: Tom Date: Sun, 02 Aug 2020 11:52:10 -0600 In-Reply-To: (Simon Marchi's message of "Sat, 1 Aug 2020 18:56:08 -0400") Message-ID: <874kplorzp.fsf@tromey.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - box5379.bluehost.com X-AntiAbuse: Original Domain - sourceware.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - tromey.com X-BWhitelist: no X-Source-IP: 174.16.104.48 X-Source-L: No X-Exim-ID: 1k2I9b-003h0b-UJ X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: 174-16-104-48.hlrn.qwest.net (bapiya) [174.16.104.48]:55402 X-Source-Auth: tom+tromey.com X-Email-Count: 3 X-Source-Cap: ZWx5bnJvYmk7ZWx5bnJvYmk7Ym94NTM3OS5ibHVlaG9zdC5jb20= X-Local-Domain: yes X-Spam-Status: No, score=-3025.2 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, JMQ_SPF_NEUTRAL, RCVD_IN_ABUSEAT, RCVD_IN_BARRACUDACENTRAL, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, RCVD_IN_SBL_CSS, SPF_HELO_PASS, SPF_NEUTRAL, TXREP, URIBL_CSS, URIBL_CSS_A autolearn=no autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 02 Aug 2020 17:52:15 -0000 >> ... though not all returns set the kind. Simon> Do you have an example? No, I didn't notice that the wait_as function sets the kind at the start. So some minus_one_ptid returns seem to use TARGET_WAITKIND_IGNORE. >> I suspect the inf-ptrace targets can be converted by just lifting the >> Linux code into in inf_ptrace_target. Simon> Assuming there isn't too much Linux-ism in there. I think the async bits are really just a pipe and the SIGCHLD stuff, which is generic across ptrace-using Unixes. (I'm not sure if that works ok with procfs or not, I'm not familiar with that.) >> /* The common code passes WNOHANG that leads to crashes, overwrite it. */ Simon> Indeed, and that's a recent addition... Yeah :( >> Other targets require a little more research. For Windows, Darwin, and >> remote-sim, I thought perhaps we could put some of the current >> resume/wait code into a separate thread. (Though in the case of the >> sim, I think it would be better to move the sims to using the remote >> protocol.) Simon> For Windows, that's what Pedro suggested here: Simon> https://sourceware.org/legacy-ml/gdb/2016-09/msg00055.html Simon> If we can avoid separate threads, I'd say it's better to, because it's more difficult Simon> to debug. For Windows, that would mean finding if there's an equivalent of SIGCHLD + Simon> the self pipe trick but for Windows. In other words, a way to wake up the event loop Simon> when we know there's an event available. There isn't a way on Windows. A thread is preferable here since then you don't have to poll -- the thread can just block in WaitForDebugEvent. Maybe we need to work around the mingw std::thread situation by introducing our own gdb::thread and using Windows APIs there when possible. Tom