From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.freebsd.org (mx2.freebsd.org [IPv6:2610:1c1:1:606c::19:2]) by sourceware.org (Postfix) with ESMTPS id 2AE50385828D for ; Wed, 27 Sep 2023 20:28:02 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 2AE50385828D Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=FreeBSD.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [96.47.72.80]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits)) (Client CN "mx1.freebsd.org", Issuer "R3" (verified OK)) by mx2.freebsd.org (Postfix) with ESMTPS id 4Rwp8H3KnFz4v3f; Wed, 27 Sep 2023 20:27:59 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from smtp.freebsd.org (smtp.freebsd.org [96.47.72.83]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "smtp.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4Rwp8H2XNnz4NLh; Wed, 27 Sep 2023 20:27:59 +0000 (UTC) (envelope-from jhb@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1695846479; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=CDbFEgDPVjgYiaBFFsJKTvZg9QnCqDGN5rtqx3W+l8A=; b=tB4bsvzG6CCifDxf0G/XVjjxRf0kxpY6TlRBvsKGG4a2b0ee/mhwN6T+vUYKzYteUG+lm2 PZp1xcRMW764serTq088g4DRkN/zgK2QaZHrtnAA6a4ePCymkhK9fkosbS3wjxTHW4XCbD BlEFvmdY9jjBrLHBD0rq9T7cC7skX8Tu+VPduEyiYVkTdTKSeGNRTArBpmmO/6tmjuYtRX AD/QbPiVo7JlQ3dG1hwrVzCm0k+RgvDpLB5A23jZVGstB+i5vIruglOy2Lqt2td86FzCJG E9utBwpawsAi2/6MEhDqe/abR/jt6LN98uZNtHpakYoFgE8iK4bp0YIIIrtnHA== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1695846479; a=rsa-sha256; cv=none; b=omHZvVzT7c0DSQnZPPDJBb6QCKhYQhodjqpbtwcBlJaMg6lLrbHFze6VgJFDoomSaQhLnv qN6LOIZYQATejDuDo9ItBiqTSd0AUO9HdwLJD8DEdlBI68uz9YqCbah0fxXhs8IBKuLYSv DzxKxiRRIeotffL03YAvO6u0GSqQNHjDjBkDkBmgVTLfyvd/alx5WzEcuDhGlaUojpCC+/ ey4AqB8dS8z/+s61EzitBFqcC5mfP/uPoExPUbDuFaZvz5vc1OxXH1Ckd+KPTiR6lNeOzu 9+4arX6/7XiGCs+FuXs5ZyW2jNqoCdSCp+sgPb9pSV8UcMV78fcpgG4WE/fQIA== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1695846479; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=CDbFEgDPVjgYiaBFFsJKTvZg9QnCqDGN5rtqx3W+l8A=; b=EiNz7F950oNpnu/QiQuSwa36JCWhdmUFZA7eHSsLGRVmBUb2pRHW1PuccqCPOhis/DfOew A36LOAqKwzPD1Ts57kOYuIAR7v1xqh15gngcUCPO65z/DLTpIUa6paeRkS+JEhvqcAJeU/ yAhEoj3w7YjN0ds5q+oif2slTeQ3uLfYRZMPwNu59T4LkIAc0q8i7QuXruv9YTKtbWEdvv 5EgrXmQkpUsyMfJKlNbGW3X8uyI1VxbM4VAGyqO2yay3ZJn8/ramHV2TnPAp5k8sefBDTW mlkiUqZvxqYOuhu/vEOnwwH34dZ2KllL/Y2ZpZfptXAJfHcZR6QEoCzp8Rq+GQ== Received: from [IPV6:2601:648:8683:39a0:7c2a:d4a:3730:4e68] (unknown [IPv6:2601:648:8683:39a0:7c2a:d4a:3730:4e68]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) (Authenticated sender: jhb) by smtp.freebsd.org (Postfix) with ESMTPSA id 4Rwp8G6lJxz1HFd; Wed, 27 Sep 2023 20:27:58 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Message-ID: <453315e3-2483-7a1d-6ecc-23adc7d24fd3@FreeBSD.org> Date: Wed, 27 Sep 2023 13:27:58 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.15.1 Subject: Re: GDB BoF notes - GNU Cauldron 2023 Content-Language: en-US To: Pedro Alves , gdb@sourceware.org References: <1e26c71e-e242-de11-a687-46e05586e608@palves.net> From: John Baldwin In-Reply-To: <1e26c71e-e242-de11-a687-46e05586e608@palves.net> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-5.8 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On 9/27/23 1:41 PM, Pedro Alves wrote: > - Can we require C++17? > > Lancelot has patches for this. > > Looked at / discussed policy established when we migrated to C++11: > https://sourceware.org/gdb/wiki/Internals%20GDB-C-Coding-Standards#When_is_GDB_going_to_start_requiring_C.2B-.2B-NN_.3F > > "Our general policy is to wait until the oldest compiler that > supports C++NN is at least 3 years old." > > Discussion about whether the bump is problematic for current > distros. > > Looked for first GCC version that claims supports C++17. In GCC 9 > release notes: "The C++17 implementation is no longer experimental." > GCC 9.1 was released on May 3, 2019. > > Do we need full C++17, though? We can use language features even if > the standard library implementation doesn't support everything. > > Were there actual ABI breakages between compiler releases before it > was made non-experimental, though? AI: ask Jonathan Wakely. > > On whether we have easy availability of a new enough compiler in > distros, in practice: > > - Tom de Vries to double check for SuSE. > > - Carlos O'Donell confirms that for RHEL we're good, because of GCC > Toolset. > > - Someone should check Debian/Ubuntu and others. > > - BSDs tend to have easy access to recent Clang. Confirming this point. Lancelot had asked me about this earlier and all of the BSD's have succifient clang or GCC in relevant releases. > - Revisiting defaults > > - Can we turn history saving on by default? Maybe default to > history on home dir by default, too (~/.gdb_history). That would > align us with bash. Some in the room have had this enabled in > their gdbinits for so long they no longer remembered this wasn't > on by default. Others weren't even aware you can turn this on. > > - Can we disable pagination by default? Surprisingly, no one in the > room expressed that they like pagination on. Sevearl people > mentioned that they have it off by default, and then use either > the terminal scroll function, or: > > "(gdb) pipe GDB_COMMAND | less" > > when necessary. +1 to both of these. One caveat about the pagination case is that I use custom commands that can sometimes generate a lot of output (e.g. walking linked-lists in a kernel crash image outputting info about each entry, or similar things for entries in descriptor rings). If one of these scripts has a bug that causes an infinite loop, the pager seems to be the only way to stop the command. In particular, Ctrl-C doesn't work in my experience to cancel a user command stuck in an infinite loop. It might be nice to ensure that Ctrl-C can cancel both user and builtin commands that are either stuck or generating reams of output. -- John Baldwin