Re: [RFC PATCH v5 08/21] hw/arm: Add DEFINE_MACHINE_[ARM_]AARCH64() macros

[BALATON Zoltan <balaton@eik.bme.hu>]

On Mon, 28 Apr 2025, Pierrick Bouvier wrote:
> On 4/28/25 3:31 AM, BALATON Zoltan wrote:
>> Since you are touching the lines using DEFINE_MACHINE it's a good
>> opportunity to change the macro to be more general to be able to keep
>> using it instead of replacing it with the boiler plate it's supposed to
>> hide. Adding one or two more parameters to the macro is not a big change
>> so I don't see why you don't want to do it. This could be addressed later
>> to revert to use the macro again but in practice it will not be addressed
>> because everybody will be busy doing other things and doing that now would
>> prevent some churn. I too, don't like doing unrelated clean up which is
>> not the main goal, but if it's not much more work then it's not
>> unreasonable to do it. I only oppose to that if it's a lot of work so I
>> would not ask such change but what I asked is not unrelated and quite
>> simple change.
>> 
>> That said, I can't stop you so if you still don't want to do it now then
>> you can move on. I don't care that much as long as you stay within hw/arm,
>> but will raise my concern again when you submit a similar patch that
>> touches parts I care more about. If others don't think it's a problem and
>> not bothered by the boiler plate code then it's not so important but
>> otherwise I think I have a valid point. I remember when I started to get
>> to know QEMU it was quite difficult to wade through all the QOM boiler
>> plate just to see what is related to the actual functionality. These
>> macros help to make code more readable and accessible for new people.
>
> Having been through that recently, I agree with you that it can be hard to 
> follow at first. Luckily, we have perfect compiler based completion for all 
> editors those days (I sincerely hope everyone spent 2 hours configuring this 
> on their own favorite one), and it's easy to see where things are defined and 
> used, even when code is cryptic.

It's not about typing but reading it. The verbose struct definitions are 
hard to follow and makes board code look more complex than it should be.

> That said, pushing to someone adding a new field the responsibility of 
> cleaning up the whole thing is not a fair request. You can't expect your 
> friends to clean your shared house because they brought a cake for dinner.

I tend to get such requests to clean up unrelated things whenever I try to 
change anything in PPC Mac emulation which I also complain about and think 
is not reasonable to ask. But I did not ask for unrelated cleanup here and 
changing the patch so you don't do this:

-DEFINE_MACHINE("none", machine_none_machine_init)
+static const TypeInfo null_machine_types[] = {
+    {
+        .name           = MACHINE_TYPE_NAME("none"),
+        .parent         = TYPE_MACHINE,
+        .class_init     = null_machine_class_init,
+    },
+};
+
+DEFINE_TYPES(null_machine_types)

but instead add the .interfaces field to a variant of DEFINE_MACHINE once 
and keep the one line definition is not something unreasonable to ask. I 
think you can ask your friends to not make a mess in the shared house 
while having a party or at least clean up after that. Adding one more 
parameter to the macro is also simple to do so I don't get why you're so 
opposed to this.

Regards,
BALATON Zoltan