Re: [PATCH v2 10/13] qdev: make properties array "const"

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

Hi,

On 21/10/24 13:35, Paolo Bonzini wrote:
> Constify all accesses to qdev properties, except for the
> ObjectPropertyAccessor itself.  This makes it possible to place them in
> read-only memory, and also lets Rust bindings switch from "static mut"
> arrays to "static"; which is advantageous, because mutable statics are
> highly discouraged.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>   include/hw/qdev-core.h       |  4 ++--
>   include/hw/qdev-properties.h |  4 ++--
>   hw/core/qdev-properties.c    | 26 +++++++++++++-------------
>   system/qdev-monitor.c        |  2 +-
>   4 files changed, 18 insertions(+), 18 deletions(-)


> -void qdev_property_add_static(DeviceState *dev, Property *prop)
> +void qdev_property_add_static(DeviceState *dev, const Property *prop)
>   {
>       Object *obj = OBJECT(dev);
>       ObjectProperty *op;
> @@ -980,7 +980,7 @@ void qdev_property_add_static(DeviceState *dev, Property *prop)
>                                field_prop_getter(prop->info),
>                                field_prop_setter(prop->info),
>                                prop->info->release,
> -                             prop);
> +                             (Property *)prop);

I like the overall patch idea, but I'm not keep on casting
const to non-const. Should we adapt the callee -- here
object_property_add() -- to also take a const argument?

>   
>       object_property_set_description(obj, prop->name,
>                                       prop->info->description);
> @@ -994,7 +994,7 @@ void qdev_property_add_static(DeviceState *dev, Property *prop)
>   }
>   
>   static void qdev_class_add_property(DeviceClass *klass, const char *name,
> -                                    Property *prop)
> +                                    const Property *prop)
>   {
>       ObjectClass *oc = OBJECT_CLASS(klass);
>       ObjectProperty *op;
> @@ -1007,7 +1007,7 @@ static void qdev_class_add_property(DeviceClass *klass, const char *name,
>                                          field_prop_getter(prop->info),
>                                          field_prop_setter(prop->info),
>                                          prop->info->release,
> -                                       prop);
> +                                       (Property *)prop);
>       }
>       if (prop->set_default) {
>           prop->info->set_default_value(op, prop);
> @@ -1046,7 +1046,7 @@ static void qdev_get_legacy_property(Object *obj, Visitor *v,
>    * Do not use this in new code!  QOM Properties added through this interface
>    * will be given names in the "legacy" namespace.
>    */
> -static void qdev_class_add_legacy_property(DeviceClass *dc, Property *prop)
> +static void qdev_class_add_legacy_property(DeviceClass *dc, const Property *prop)
>   {
>       g_autofree char *name = NULL;
>   
> @@ -1058,12 +1058,12 @@ static void qdev_class_add_legacy_property(DeviceClass *dc, Property *prop)
>       name = g_strdup_printf("legacy-%s", prop->name);
>       object_class_property_add(OBJECT_CLASS(dc), name, "str",
>           prop->info->print ? qdev_get_legacy_property : prop->info->get,
> -        NULL, NULL, prop);
> +        NULL, NULL, (Property *)prop);
>   }