Re: [RFC PATCH-for-9.1? 2/2] hw/intc/arm_gic: Only provide query-gic-capabilities when GIC built-in

[Peter Maydell <peter.maydell@linaro.org>]

On Wed, 7 Aug 2024 at 12:10, Markus Armbruster <armbru@redhat.com> wrote:
> Having to manually include a configuration header like CONFIG_DEVICES
> wherever you use configuration symbols strikes me as unadvisable when
> uses include checking for definedness, such as #ifdef: silent miscompile
> when you forget to include.
>
> This is why Autoconf wants you to include config.h first in any .c: it
> makes #ifdef & friends safe.
>
> qemu/osdep.h does include some configuration headers:
>
>     #include "config-host.h"
>     #ifdef COMPILING_PER_TARGET
>     #include CONFIG_TARGET
>     #else
>     #include "exec/poison.h"
>     #endif
>
> Why not CONFIG_DEVICES?

The stuff in CONFIG_DEVICES is target-specific, so wanting
to include it should be rare (currently we include it in
only about 25 files). Any file that includes it has to be
a compile-per-target file, and generally we'd rather avoid that.
Plus it's a bit odd to need to change code based on whether
some other device was configured into the system, so I think
that's something worth restricting to only files that effectively
opt in to it.

thanks
-- PMM