Am 23.11.2012 16:56, schrieb Paolo Bonzini:
> Trying to cast a NULL value will cause a crash. Returning
> NULL is also sensible, and it is also what the type-unsafe
> DO_UPCAST macro does.
>
> Reported-by: Markus Armbruster <arm...@redhat.com>
> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
I believe we had a lengthy discussion of where to place the NULL
checks... seems that was never followed up with a v2 then.
In practice however most of NULL assertions stem from misuses of the
cast macros, i.e. using them before qdev_create() or so, which we should
not hide because they lead to segfaults later.
> ---
> qom/object.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/qom/object.c b/qom/object.c
> index d7092b0..2e18c9a 100644
> --- a/qom/object.c
> +++ b/qom/object.c
> @@ -417,7 +417,7 @@ void object_delete(Object *obj)
>
> Object *object_dynamic_cast(Object *obj, const char *typename)
> {
> - if (object_class_dynamic_cast(object_get_class(obj), typename)) {
> + if (obj && object_class_dynamic_cast(object_get_class(obj), typename)) {
> return obj;
> }
>
This is followed by return NULL;
Ack on this part.
> @@ -430,7 +430,7 @@ Object *object_dynamic_cast_assert(Object *obj, const
> char *typename)
>
> inst = object_dynamic_cast(obj, typename);
>
> - if (!inst) {
> + if (!inst && obj) {
> fprintf(stderr, "Object %p is not an instance of type %s\n",
> obj, typename);
> abort();
This is followed by return inst;
Since this function clearly has assert in the name I don't think this is
right. I would expect %p to print 0x0 and the function to abort.
Regards,
Andreas
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