From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gproxy2-pub.mail.unifiedlayer.com (gproxy2-pub.mail.unifiedlayer.com [69.89.18.3]) by sourceware.org (Postfix) with ESMTPS id 8A22438518B4 for ; Wed, 14 Dec 2022 16:18:03 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 8A22438518B4 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=tromey.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=tromey.com Received: from cmgw14.mail.unifiedlayer.com (unknown [10.0.90.129]) by progateway4.mail.pro1.eigbox.com (Postfix) with ESMTP id EAEF7100476D7 for ; Wed, 14 Dec 2022 16:17:51 +0000 (UTC) Received: from box5379.bluehost.com ([162.241.216.53]) by cmsmtp with ESMTP id 5US7pfWKRXEB25US7poEYy; Wed, 14 Dec 2022 16:17:51 +0000 X-Authority-Reason: nr=8 X-Authority-Analysis: v=2.4 cv=Ab50o1bG c=1 sm=1 tr=0 ts=6399f72f a=ApxJNpeYhEAb1aAlGBBbmA==:117 a=ApxJNpeYhEAb1aAlGBBbmA==:17 a=dLZJa+xiwSxG16/P+YVxDGlgEgI=:19 a=sHyYjHe8cH0A:10:nop_rcvd_month_year a=Qbun_eYptAEA:10:endurance_base64_authed_username_1 a=CCpqsmhAAAAA:8 a=sFov_Ddo2cfXde49IfIA:9 a=ul9cdbp4aOFLsgKbc677:22 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=ICAH/VO48+g3A+iSagq0vmN7M1UmWpGNxfqZbI4uoqk=; b=AyfRJg4oAWCdaT1VlD3fAeBCX6 Hwmvv378PmKnpuqUEFVLK8qQL5E906EL5B+Dw1YP/naT0t77IhMPQUBywMXVlkYzJ8mgQuSaf4nyN PqnHVb7DlmKwGVIf+RN0dEc8v; Received: from 97-122-76-186.hlrn.qwest.net ([97.122.76.186]:56978 helo=murgatroyd) by box5379.bluehost.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1p5US7-002vny-Na; Wed, 14 Dec 2022 09:17:51 -0700 From: Tom Tromey To: Andrew Burgess via Gdb-patches Cc: Andrew Burgess Subject: Re: [PATCH 2/2] gdb: fix crash when getting the value of a label symbol References: <9ec9a8db6a02169c4b18248f131715c54811550a.1671013621.git.aburgess@redhat.com> X-Attribution: Tom Date: Wed, 14 Dec 2022 09:17:47 -0700 In-Reply-To: <9ec9a8db6a02169c4b18248f131715c54811550a.1671013621.git.aburgess@redhat.com> (Andrew Burgess via Gdb-patches's message of "Wed, 14 Dec 2022 10:28:33 +0000") Message-ID: <87cz8mdkno.fsf@tromey.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (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: 97.122.76.186 X-Source-L: No X-Exim-ID: 1p5US7-002vny-Na X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: 97-122-76-186.hlrn.qwest.net (murgatroyd) [97.122.76.186]:56978 X-Source-Auth: tom+tromey.com X-Email-Count: 3 X-Source-Cap: ZWx5bnJvYmk7ZWx5bnJvYmk7Ym94NTM3OS5ibHVlaG9zdC5jb20= X-Local-Domain: yes X-Spam-Status: No, score=-3018.9 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,JMQ_SPF_NEUTRAL,RCVD_IN_BL_SPAMCOP_NET,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: >>>>> "Andrew" == Andrew Burgess via Gdb-patches writes: Andrew> (gdb) p some_label Andrew> No symbol "some_label" in current context. ... Andrew> This all seems a little strange to me, it feels like asking about a Andrew> goto label would not be an unreasonable thing for a user to do. The issue is that that in C, there's no way to refer to a label in an expression, so we'd need an extension of some kind. GNU C has the "&&" address-of-label extension, I suppose we could do that: (info "(gcc) Labels as Values") Andrew> The problem is that label symbols are created using the Andrew> builtin_core_addr type, which is a pure integer type. Andrew> The fix I propose is to change the type used for the value of the Andrew> label symbol, instead of using builtin_core_addr type, we could use Andrew> builtin_func_ptr, after this calling store_typed_address is fine (the Andrew> call to store_typed_address is done indirectly through Andrew> value_from_pointer). In the GNU C extension, a label value uses "void *" as the type. Unclear to me which is preferable, or if users are even likely to notice or care if we decide to change it (like, when/if we implement the extension). Anyway the patch looks fine to me. Tom