From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gateway33.websitewelcome.com (gateway33.websitewelcome.com [192.185.146.119]) by sourceware.org (Postfix) with ESMTPS id 5AE8F3858D35 for ; Sat, 1 Aug 2020 20:46:10 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 5AE8F3858D35 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 cm17.websitewelcome.com (cm17.websitewelcome.com [100.42.49.20]) by gateway33.websitewelcome.com (Postfix) with ESMTP id BE6E444BAA for ; Sat, 1 Aug 2020 15:46:09 -0500 (CDT) Received: from box5379.bluehost.com ([162.241.216.53]) by cmsmtp with SMTP id 1yOPk734PdbRz1yOPkBwP0; Sat, 01 Aug 2020 15:46:09 -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=uMnusLkPCVtKvngl/InQe5QHQzbcwzVFDce05l7BRMU=; b=J/lBVjPsOIWhfSZmyUs1s89mww Xm1GkGj0zJCod3TY2j0IaAq8hWv58K6s6tCNBoKnhYNDZ5jzes8SDUYwh12thZdJ/96tfA3GO+4+X hjjGdtpUt02wnrvqAGpAbX43J; Received: from 174-16-104-48.hlrn.qwest.net ([174.16.104.48]:53080 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 1k1yOP-003wjm-E7; Sat, 01 Aug 2020 14:46:09 -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> X-Attribution: Tom Date: Sat, 01 Aug 2020 14:46:08 -0600 In-Reply-To: <9d4243a6-3b43-802b-b1d6-4cd0497205af@simark.ca> (Simon Marchi's message of "Sat, 1 Aug 2020 12:14:36 -0400") Message-ID: <87d04ap01b.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: 1k1yOP-003wjm-E7 X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: 174-16-104-48.hlrn.qwest.net (bapiya) [174.16.104.48]:53080 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_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: Sat, 01 Aug 2020 20:46:12 -0000 Simon> I don't know if this makes sense: you tell the core of GDB that some Simon> process was signalled (terminated by a signal), but you don't tell Simon> what process it is. I am not sure what the core of GDB can do with Simon> this information. Simon> The contract that the `wait` implementations must respect is not Simon> very well documented I believe, so it's not clear which value is Simon> valid with which event. Yeah. I think it would be good to fix this. The reason I had it return minus_one_ptid is this text in target/target.h: Return pid of child, or -1 in case of error; store status through argument pointer STATUS. remote_target::wait does this as well, though perhaps not with this target waitkind, e.g.: status->kind = TARGET_WAITKIND_NO_RESUMED; return minus_one_ptid; or if (status->kind == TARGET_WAITKIND_NO_RESUMED) return minus_one_ptid; ... though not all returns set the kind. Simon> Note that this waitpid call is blocking (and there's no async stuff in Simon> inf-ptrace.c), so I presume that this is only used in sync targets. Yeah. I found this because I was wondering what it would take to convert the remaining sync targets, and have only target-async left. I suspect the inf-ptrace targets can be converted by just lifting the Linux code into in inf_ptrace_target. This comment in nbsd-nat.c is worrying though: /* The common code passes WNOHANG that leads to crashes, overwrite it. */ 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> Perhaps we could return TARGET_WAITKIND_NO_RESUMED in both cases? remote.c does this in at least one case, though apparently not in all. Tom