From: Simon Marchi <simark@simark.ca>
To: Andrew Burgess <aburgess@redhat.com>, gdb-patches@sourceware.org
Subject: Re: [PATCH] gdb: fix target_ops reference count for some cases
Date: Mon, 26 Sep 2022 10:16:19 -0400 [thread overview]
Message-ID: <1ff3e5de-f218-4657-0798-525158ba4cbe@simark.ca> (raw)
In-Reply-To: <87a66re30o.fsf@redhat.com>
>> Just wondering, why do we need to restore explicitly the current
>> pspace, instead of using just scoped_restore_current_thread?
>>
>> scoped_restore_current_pspace_and_thread's doc says:
>>
>> /* Save/restore the current program space, thread, inferior and frame.
>> Use this when you need to call
>> switch_to_program_space_and_thread. */
>>
>> ... but you are not using switch_to_program_space_and_thread here.
>> Maybe it's ok and I just don't understand. Same in
>> ~scoped_mock_context.
>
> I suspect the comment you quote is just out of date.
>
> switch_to_program_space_and_thread can end up calling
> switch_to_inferior_no_thread if there are no running threads in the
> program space being switched too. But, even if switch_to_thread does
> end up being called we:
>
> - set the program space,
> - set the inferior,
> - set the current thread,
> - reinit the frame cache,
>
> By comparison, switch_to_inferior_no_thread does:
>
> - sets the program space,
> - sets the inferior,
> - sets the current thread (to nullptr this time though),
> - reinits the frame cache,
>
> As you can see they do the same set of things, all of which I think
> should be reverted once we leave the scope, hence
> scoped_restore_current_pspace_and_thread seems like the way to go.
Hmm okay, but won't scoped_restore_current_thread always restore the
pspace one way or another? scoped_restore_current_thread::restore will
either call switch_to_thread or switch_to_inferior_no_thread, which both
end up setting the pspace. I just don't understand why
scoped_restore_current_pspace_and_thread exists, it seems like
scoped_restore_current_thread would always work where
scoped_restore_current_pspace_and_thread is used. I must be missing
something, scoped_restore_current_pspace_and_thread must have been added
for a reason.
Simon
next prev parent reply other threads:[~2022-09-26 14:16 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-21 13:12 Andrew Burgess
2022-09-21 15:30 ` Simon Marchi
2022-09-22 14:21 ` Andrew Burgess
2022-09-22 14:52 ` Simon Marchi
2022-09-22 15:00 ` Simon Marchi
2022-09-22 17:24 ` Andrew Burgess
2022-09-26 14:16 ` Simon Marchi [this message]
2022-10-01 20:58 ` Andrew Burgess
2022-10-02 17:04 ` [PATCHv2 0/7] " Andrew Burgess
2022-10-02 17:04 ` [PATCHv2 1/7] gdb/remote: remove some manual reference count handling Andrew Burgess
2022-10-02 17:04 ` [PATCHv2 2/7] gdb: remove decref_target Andrew Burgess
2022-10-02 17:04 ` [PATCHv2 3/7] gdb: have target_stack automate reference count handling Andrew Burgess
2022-10-02 17:04 ` [PATCHv2 4/7] gdb: remove the pop_all_targets (and friends) global functions Andrew Burgess
2022-10-05 20:49 ` Lancelot SIX
2022-10-06 11:14 ` Andrew Burgess
2022-10-02 17:04 ` [PATCHv2 5/7] gdb: ensure all targets are popped before an inferior is destructed Andrew Burgess
2022-10-02 17:04 ` [PATCHv2 6/7] gdb/maint: add core file name to 'maint info program-spaces' output Andrew Burgess
2022-10-02 17:21 ` Eli Zaretskii
2022-10-02 17:04 ` [PATCHv2 7/7] gdb: some process_stratum_target should not be shared Andrew Burgess
2022-10-02 17:21 ` Eli Zaretskii
2022-10-05 21:15 ` Lancelot SIX
2022-10-06 11:44 ` Andrew Burgess
2022-11-18 16:42 ` [PATCHv3 0/7] gdb: fix target_ops reference count for some cases Andrew Burgess
2022-11-18 16:42 ` [PATCHv3 1/7] gdb/remote: remove some manual reference count handling Andrew Burgess
2022-11-18 16:42 ` [PATCHv3 2/7] gdb: remove decref_target Andrew Burgess
2022-11-18 17:22 ` Tom Tromey
2022-11-18 16:42 ` [PATCHv3 3/7] gdb: have target_stack automate reference count handling Andrew Burgess
2022-11-18 17:25 ` Tom Tromey
2022-11-18 16:42 ` [PATCHv3 4/7] gdb: remove the pop_all_targets (and friends) global functions Andrew Burgess
2022-11-18 17:29 ` Tom Tromey
2022-11-18 16:42 ` [PATCHv3 5/7] gdb: ensure all targets are popped before an inferior is destructed Andrew Burgess
2022-11-18 16:42 ` [PATCHv3 6/7] gdb/maint: add core file name to 'maint info program-spaces' output Andrew Burgess
2022-11-18 17:03 ` Eli Zaretskii
2022-11-18 16:42 ` [PATCHv3 7/7] gdb: some process_stratum_target should not be shared Andrew Burgess
2022-11-18 17:02 ` Eli Zaretskii
2022-11-18 18:04 ` Tom Tromey
2022-12-14 13:57 ` Andrew Burgess
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