Re: [PATCH] meson.build: Always require an objc compiler on macos hosts

[Daniel P . Berrangé]

On Mon, Mar 11, 2024 at 01:33:34PM +0000, Peter Maydell wrote:
> We currently only insist that an ObjectiveC compiler is present on
> macos hosts if we're building the Cocoa UI.  However, since then
> we've added some other parts of QEMU which are also written in ObjC:
> the coreaudio audio backend, and the vmnet net backend.  This means
> that if you try to configure QEMU on macos with --disable-cocoa the
> build will fail:
> 
> ../meson.build:3741:13: ERROR: No host machine compiler for 
> 'audio/coreaudio.m'
> 
> Since in practice any macos host will have an ObjC compiler
> available, rather than trying to gate the compiler detection on an
> increasingly complicated list of every bit of QEMU that uses ObjC,
> just require it unconditionally on macos hosts.
> 
> Resolves https://gitlab.com/qemu-project/qemu/-/issues/2138
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
> Per the commit message, in theory we could allow a no-objc
> build and disable coreaudio, vmnet, etc. But I didn't really see
> a reason why that would be useful, and it's bound to keep
> breaking unless we actively defend it in CI. So I preferred
> to simply require ObjC on macos.

Yeah, I think simplicity wins here, unless someone can provide
a compelling reason why they absolutely must be able to build
without objc being present, even if it were unused.

>  meson.build | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>


> 
> diff --git a/meson.build b/meson.build
> index f9dbe7634e5..e3fab8ce9ff 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -66,7 +66,7 @@ if host_os == 'windows' and add_languages('cpp', required: 
> false, native: false)
>    cxx = meson.get_compiler('cpp')
>  endif
>  if host_os == 'darwin' and \
> -   add_languages('objc', required: get_option('cocoa'), native: false)
> +   add_languages('objc', required: true, native: false)
>    all_languages += ['objc']
>    objc = meson.get_compiler('objc')
>  endif
> -- 
> 2.34.1
> 

With regards,
Daniel
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