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From: Tom Tromey <tom@tromey.com>
To: Simon Marchi via Gdb-patches <gdb-patches@sourceware.org>
Subject: Re: [PATCH 15/16] gdb: make cmd_list_element var an optional union
Date: Wed, 28 Jul 2021 13:47:36 -0600	[thread overview]
Message-ID: <87wnpacjaf.fsf@tromey.com> (raw)
In-Reply-To: <20210714045520.1623120-16-simon.marchi@polymtl.ca> (Simon Marchi via Gdb-patches's message of "Wed, 14 Jul 2021 00:55:19 -0400")

>>>>> "Simon" == Simon Marchi via Gdb-patches <gdb-patches@sourceware.org> writes:

Simon> I propose changing cmd_list_element to be a union of all the possible
Simon> pointer types.  Fundamentally, this doesn't change much what is
Simon> happening.  But I think this helps understand better how the field is
Simon> used and get a bit of type safety (while it is still possible to use the
Simon> wrong member at some point, we can't cast to something completely
Simon> unrealted).

Makes sense to me.

Simon> I wrapped the union in an optional, because we need to check in some
Simon> spots whether var is set or not.  I think that conceptually, an optional
Simon> makes the most sense.  Another option would be to pick an arbitrary
Simon> member of the union and compare it to nullptr, whenever we want to know
Simon> whether var is set, but that seems a bit more hack-ish.

There could be a "void *null_if_not_set" member that's only used for the
check.  This would save some space.  Not sure it matters though.

Tom

  parent reply	other threads:[~2021-07-28 21:19 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-14  4:55 [PATCH 00/16] Bunch of commands related cleanups Simon Marchi
2021-07-14  4:55 ` [PATCH 01/16] gdb/testsuite: split gdb.python/py-parameter.exp in procs Simon Marchi
2021-07-14  4:55 ` [PATCH 02/16] gdb.base/setshow.exp: use save_vars to save/restore gdb_prompt Simon Marchi
2021-07-14  4:55 ` [PATCH 03/16] gdb.base/setshow.exp: split in procs Simon Marchi
2021-07-14  4:55 ` [PATCH 04/16] gdb.base/setshow.exp: fix duplicate test name Simon Marchi
2021-07-14  4:55 ` [PATCH 05/16] gdb: un-share set_inferior_cwd declaration Simon Marchi
2021-07-14  4:55 ` [PATCH 06/16] gdb: remove inferior::{argc,argv} Simon Marchi
2021-07-14  4:55 ` [PATCH 07/16] gdb: add setter/getter for inferior arguments Simon Marchi
2021-07-14  4:55 ` [PATCH 08/16] gdb: add setter/getter for inferior cwd Simon Marchi
2021-07-14  4:55 ` [PATCH 09/16] gdb: make inferior::m_args an std::string Simon Marchi
2021-07-14  4:55 ` [PATCH 10/16] gdb: make inferior::m_cwd " Simon Marchi
2021-07-14  4:55 ` [PATCH 11/16] gdb: make inferior::m_terminal " Simon Marchi
2021-07-14  4:55 ` [PATCH 12/16] gdb: rename cfunc to simple_func Simon Marchi
2021-07-14  4:55 ` [PATCH 13/16] gdb: remove cmd_list_element::function::sfunc Simon Marchi
2021-07-28 19:10   ` Tom Tromey
2021-07-28 21:17     ` Simon Marchi
2021-07-29 17:33       ` Tom Tromey
2021-07-14  4:55 ` [PATCH 14/16] gdb/testsuite: test get/set value of unregistered Guile parameter Simon Marchi
2021-07-23 19:42   ` Simon Marchi
2021-07-14  4:55 ` [PATCH 15/16] gdb: make cmd_list_element var an optional union Simon Marchi
2021-07-14 12:08   ` Lancelot SIX
2021-07-14 17:12     ` Lancelot SIX
2021-07-14 19:22       ` Simon Marchi
2021-07-14 23:22         ` Lancelot SIX
2021-07-19 14:32           ` Simon Marchi
2021-07-19 19:52             ` Simon Marchi
2021-07-20 23:03               ` Lancelot SIX
2021-07-23 19:56                 ` Simon Marchi
2021-07-23 20:46                   ` Lancelot SIX
2021-07-23 21:15                     ` Simon Marchi
2021-07-23 22:55                       ` Lancelot SIX
2021-07-24  2:04                         ` Simon Marchi
2021-07-28 20:13                 ` Tom Tromey
2021-07-28 20:45                   ` Lancelot SIX
2021-07-29 17:47                     ` Tom Tromey
2021-07-29 20:12                       ` Lancelot SIX
2021-07-30  2:09                         ` Simon Marchi
2021-07-30 17:47                           ` Lancelot SIX
2021-07-18 15:44   ` Lancelot SIX
2021-07-19 14:19     ` Simon Marchi
2021-07-19 20:58       ` Lancelot SIX
2021-07-28 19:47   ` Tom Tromey [this message]
2021-07-28 20:59     ` Simon Marchi
2021-07-29 17:41       ` Tom Tromey
2021-07-29 17:44         ` Simon Marchi
2021-07-29 17:49           ` Tom Tromey
2021-07-29 18:00             ` Simon Marchi
2021-07-14  4:55 ` [PATCH 16/16] gdb: make string-like set show commands use std::string variable Simon Marchi
2021-07-28 20:27   ` Tom Tromey
2021-07-28 21:03     ` Simon Marchi

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