Re: [PATCH] ui/gtk: fix NULL pointer dereference

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 3/8/21 3:17 PM, Akihiko Odaki wrote:
> 2021年3月8日(月) 23:03 Christian Schoenebeck <qemu_oss@crudebyte.com>:
>>
>> BTW, there is __nonnull supported by clang, e.g.:
>>
>> static void foo(void *__nonnull p) {
>>         ...
>> }
>>
>> Maybe as an optionally defined macro (if supported by compiler) this could be
>> a useful tool for such intended nonnull designs, as it immediately emits
>> compiler errors.
>>
>> Best regards,
>> Christian Schoenebeck
>>
>>
> 
> GCC has nonnull attribute and clang accepts it too. However, it
> specifies argument indices, which is harder to understand and to
> maintain.
> __attribute__((nonnull(2)))
> void f(void *k, void *l);

Richard once suggested to add QEMU_NONNULL(), I have been using
it on a series trying to enforce non-null uses of QOM
'struct Object *owner' but it didn't work out because migrations
of MemoryRegion, some have NULL owner in MachineState.

I also discarded it because Daniel said it could have side-effects
https://www.mail-archive.com/qemu-devel@nongnu.org/msg720739.html