configure: How to pass flags to the Objective-C compiler?

configure: How to pass flags to the Objective-C compiler?

[Joshua Seaton]

Hi all,

How does one pass Objective-C compilation flags (e.g., a sysroot
specification) when configuring/building? `configure` exposes
`--extra-cflags` and `--extra-cxxflags` for C/C++ compilation, but
there isn't an equivalent for Objective-C.

In my particular case, I'd like to specify a particular sysroot for a
macOS build.


Joshua.

Re: configure: How to pass flags to the Objective-C compiler?

[Philippe Mathieu-Daudé via]

Hi Joshua,

On 18/2/22 22:58, Joshua Seaton wrote:
> Hi all,
> 
> How does one pass Objective-C compilation flags (e.g., a sysroot
> specification) when configuring/building? `configure` exposes
> `--extra-cflags` and `--extra-cxxflags` for C/C++ compilation, but
> there isn't an equivalent for Objective-C.

You can use this patch (which is going to be merged soon):
https://lore.kernel.org/qemu-devel/20220215080307.69550-3-f4bug@amsat.org/

> In my particular case, I'd like to specify a particular sysroot for a
> macOS build.

Regards,

Phil.

Re: configure: How to pass flags to the Objective-C compiler?

[Joshua Seaton]

Thanks, Philippe.
I was in luck that you already had this prepared.
My naive read of that patch is that it covers specification at the
levels of the configure and meson front-ends, but that it still does
not wire that up to the build (beyond the diagnostic `summary_info`
addition). Is that accurate? If so, will there be follow-up patches?
If not, could you clarify how this amounts to affecting Objective-C
compilation steps? The other references to `objc_args` I see in the
meson build only seem like they amount to kwarg whitelisting for
certain classes (but, then again, I don't yet understand how the meson
build works).


Joshua.

On Fri, Feb 18, 2022 at 2:14 PM Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
>
> Hi Joshua,
>
> On 18/2/22 22:58, Joshua Seaton wrote:
> > Hi all,
> >
> > How does one pass Objective-C compilation flags (e.g., a sysroot
> > specification) when configuring/building? `configure` exposes
> > `--extra-cflags` and `--extra-cxxflags` for C/C++ compilation, but
> > there isn't an equivalent for Objective-C.
>
> You can use this patch (which is going to be merged soon):
> https://lore.kernel.org/qemu-devel/20220215080307.69550-3-f4bug@amsat.org/
>
> > In my particular case, I'd like to specify a particular sysroot for a
> > macOS build.
>
> Regards,
>
> Phil.
>

Re: configure: How to pass flags to the Objective-C compiler?

[Paolo Bonzini]

On 2/19/22 20:17, Joshua Seaton wrote:
> Is that accurate? If so, will there be follow-up patches?
> If not, could you clarify how this amounts to affecting Objective-C
> compilation steps?

This entry in the machine file affects the compilation steps:

+  test -n "$objcc" && echo "objc_args = [$(meson_quote $OBJCFLAGS $EXTRA_OBJCFLAGS)]" >> $cross

Paolo

Re: configure: How to pass flags to the Objective-C compiler?

[Joshua Seaton]

> You can use this patch (which is going to be merged soon):
Any ETA on when this will merge?

> This entry in the machine file affects the compilation steps:
>
> +  test -n "$objcc" && echo "objc_args = [$(meson_quote $OBJCFLAGS $EXTRA_OBJCFLAGS)]" >> $cross
Great! I had naively assumed that there was more plumbing involved
than merely defining the variable`objc_args`.


Joshua.