Re: [PATCH 1/2] bsd-user: Only process meson rules on BSD host

[Daniel P . Berrangé]

On Mon, Sep 27, 2021 at 12:01:02AM +0200, Philippe Mathieu-Daudé wrote:
> Reported-by: Warner Losh <imp@bsdimp.com>
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
>  bsd-user/meson.build | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/bsd-user/meson.build b/bsd-user/meson.build
> index 03695493408..a7607e1c884 100644
> --- a/bsd-user/meson.build
> +++ b/bsd-user/meson.build
> @@ -1,3 +1,7 @@
> +if not config_host.has_key('CONFIG_BSD')
> +  subdir_done()
> +endif
> +
>  bsd_user_ss.add(files(
>    'bsdload.c',
>    'elfload.c',

If we look at the big picture across the root meson.build, and this
meson.build we have


  bsd_user_ss = ss.source_set()

  ...

  bsd_user_ss.add(files(
    'bsdload.c',
    'elfload.c',
    'main.c',
    'mmap.c',
    'signal.c',
    'strace.c',
    'syscall.c',
    'uaccess.c',
  ))

  ...

  bsd_user_ss.add(files('gdbstub.c'))
  specific_ss.add_all(when: 'CONFIG_BSD_USER', if_true: bsd_user_ss)


So without this change, we're already correctly dropping bsd_user_ss
in its entirity, when not on BSD.

With this change, we're dropping some, but not all, of bsd_user_ss
files - gdbstub.c remains.

So this change on its own doesn't make a whole lot of sense.

If we look at linux-user/meson.build though things are more complex.
There we have alot of sub-dirs, and meson.biuld in those dirs adds
generators for various files. So conceivably skipping linux-user
will mean we won't auto-generate files we don't need on non-Linux.

With that in mind, I think it makes conceptual sense to have this
bsd-user/meson.build change, for the purpose of design consistency,
even if it doesn't have any real world benefit for bsd-user today.

Regards,
Daniel
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