From: Markus Armbruster <armbru@redhat.com>
To: Thomas Huth <thuth@redhat.com>
Cc: qemu-trivial@nongnu.org,
"Philippe Mathieu-Daudé" <philmd@redhat.com>,
qemu-devel@nongnu.org
Subject: Re: [PATCH 2/4] Do not include hw/boards.h if it's not really necessary
Date: Sat, 17 Apr 2021 11:50:11 +0200 [thread overview]
Message-ID: <87o8ed1bqk.fsf@dusky.pond.sub.org> (raw)
In-Reply-To: <f877e682-7c9b-26d8-1ef5-b22b268bb29e@redhat.com> (Thomas Huth's message of "Fri, 16 Apr 2021 20:04:48 +0200")
Thomas Huth <thuth@redhat.com> writes:
> On 16/04/2021 19.53, Philippe Mathieu-Daudé wrote:
>> Hi Thomas,
>> On 4/16/21 7:13 PM, Thomas Huth wrote:
>>> Stop including hw/boards.h in files that don't need it.
>>>
>>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>>> ---
>>> accel/tcg/tcg-accel-ops-icount.c | 1 -
>>> accel/tcg/tcg-accel-ops-rr.c | 1 -
>>> accel/tcg/tcg-accel-ops.c | 1 -
>>> hw/acpi/cpu.c | 1 -
>>> hw/acpi/memory_hotplug.c | 1 -
>>> hw/alpha/typhoon.c | 1 -
>>> hw/arm/aspeed.c | 1 -
>> It requires the macros declared by:
>> OBJECT_DECLARE_TYPE(MachineState, MachineClass, MACHINE)
>
> "hw/boards.h" is already included in include/hw/arm/aspeed.h, that's
> why it's working ... Hmm, do we have a policy whether a header should
> be included again in the .c file if it's already included by a .h
> file?
I'm not aware of a formal policy.
The most common "method" for dealing with #include is probably "when the
compiler demands declarations, throw #include at it until it shuts up".
This "method" only ever adds, never deletes. It can easily lead to
including headers many times, and to including headers unnecessarily.
Including many times isn't much of a problem in practice. A
sufficiently smart C compiler should be able to skip #include of a
"safe" header it has already seen, so redundant #include should not slow
down the build noticeably. I prefer to avoid / delete obviously
duplicate inclusions anyway.
Including unnecessarily *is* a problem. A massive one. But it's not
what you asked about.
[...]
next prev parent reply other threads:[~2021-04-17 9:51 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-16 17:13 [PATCH for-6.1 0/4] Remove more superfluous include statements Thomas Huth
2021-04-16 17:13 ` [PATCH 1/4] Do not include sysemu/sysemu.h if it's not really necessary Thomas Huth
2021-04-30 15:59 ` Laurent Vivier
2021-04-16 17:13 ` [PATCH 2/4] Do not include hw/boards.h " Thomas Huth
2021-04-16 17:53 ` Philippe Mathieu-Daudé
2021-04-16 18:04 ` Thomas Huth
2021-04-17 9:50 ` Markus Armbruster [this message]
2021-04-30 15:59 ` Laurent Vivier
2021-04-16 17:13 ` [PATCH 3/4] Do not include cpu.h " Thomas Huth
2021-04-30 15:59 ` Laurent Vivier
2021-04-16 17:13 ` [PATCH 4/4] Do not include exec/address-spaces.h " Thomas Huth
2021-04-30 15:59 ` Laurent Vivier
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