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Re: [Qemu-devel] [PATCH 00/18] Clean up includes to reduce compile time
From: |
Markus Armbruster |
Subject: |
Re: [Qemu-devel] [PATCH 00/18] Clean up includes to reduce compile time |
Date: |
Wed, 31 Jan 2018 09:31:49 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.3 (gnu/linux) |
Philippe Mathieu-Daudé <address@hidden> writes:
> On 01/30/2018 07:21 AM, Markus Armbruster wrote:
>> We have awfully many "touch it, recompile the world" headers. Right
>> now, I count about fifty that are prerequisites of more than half the
>> objects in my "build everything" tree.
>>
>> Some of them are that way by necessity. Many of them are not. This
>> series takes care of six I happen to touch, because serve as their
>> maintainer:
>>
>> include/qapi/qmp/qdict.h
>> include/qapi/qmp/qlist.h
>> include/qapi/qmp/qnull.h
>> include/qapi/qmp/qnum.h
>> include/qapi/qmp/qobject.h
>> include/qemu/option.h
>>
>> Before this series, touching any of these recompiles more than 95% of
>> my objects. That's more than 4500 compiler runs. After this series,
>> only 0.3% - 8% of my objects get recompiled.
>
> nice cleanup :)
>
> No more comment than what Eric said (mostly newlines),
> and Zoltan regarding <qemu/osdep.h>, so
> Reviewed-by: Philippe Mathieu-Daudé <address@hidden>
Thanks!
> Is there a way to check if an header got used or not?
> (thinking about a patchew check to not add headers until effectively used).
The only one I know is "drop the include and see whether it still
compiles". Would be nice if the compiler could report superfluous
headers.
For a header, "compiles" means a .c file containing just two includes
(qemu/osdep.h and the header) compiles. Many of our headers don't.
- Re: [Qemu-devel] [PATCH 15/18] Include qapi/qmp/qnull.h exactly where needed, (continued)
- [Qemu-devel] [PATCH 14/18] Include qapi/qmp/qnum.h exactly where needed, Markus Armbruster, 2018/01/30
- [Qemu-devel] [PATCH 04/18] Drop superfluous includes of qapi/qmp/qerror.h, Markus Armbruster, 2018/01/30
- [Qemu-devel] [PATCH 11/18] Include qapi/qmp/qdict.h exactly where needed, Markus Armbruster, 2018/01/30
- [Qemu-devel] [PATCH 09/18] Include qapi/qmp/qobject.h exactly where needed, Markus Armbruster, 2018/01/30
- Re: [Qemu-devel] [PATCH 00/18] Clean up includes to reduce compile time, Philippe Mathieu-Daudé, 2018/01/30
- Re: [Qemu-devel] [PATCH 00/18] Clean up includes to reduce compile time,
Markus Armbruster <=
- Re: [Qemu-devel] [PATCH 00/18] Clean up includes to reduce compile time, no-reply, 2018/01/30
- Re: [Qemu-devel] [PATCH 00/18] Clean up includes to reduce compile time, no-reply, 2018/01/30
- Re: [Qemu-devel] [PATCH 00/18] Clean up includes to reduce compile time, Thomas Huth, 2018/01/31