Re: [Qemu-devel] [RFC PATCH v1 0/7] QOM Super class access

[Michael S. Tsirkin]

On Tue, Jun 18, 2013 at 07:43:11PM +1000, address@hidden wrote:
> From: Peter Crosthwaite <address@hidden>
> 
> 
> This series enables QOM super class access and demostrates some usages.
> Replaces the save->override->call via FooClass technique, to reduce
> some of the boiler plate in recently fully QOMified devices.
> 
> Applied the change to ARM CPU, MB CPU and some of Andreas's recently
> QOMified i386 devices, all which have the save->override->call issue.
> ARMCPU I've done a brief test on and seems to work.
> 
> ARM CPU was particularly difficult, as it has 3 layers of heirachy,
> where a non-concrete class (TYPE_ARM_CPU) need to super class itself
> (to TYPE_CPU). This sees the need for super-classers to specify their
> expected base class level. See patches for illustration.
> 
> The main future work to the series is to apply the change pattern to
> the reset of the tree

Looks good to me overall.
Some nits:
- Super is an immediate parent in java and python.
- One of the design points of QOM is that it let
  you ignore which class is a parent and which is a child.
  All casts look the same.

So, why do we need the new APIs with _SUPER?
What's wrong with simple
        object_class_by_name()
and casting to that?


> 
> Peter Crosthwaite (7):
>   target-arm/cpu.c: delete un-needed instance/class sizes
>   qom: Add super class accessor
>   qdev-core: Introduce DEVICE super class cast macros
>   qom/cpu: Introduce CPU super class cast macros
>   target-arm: Remove ARMCPUClass
>   target-microblaze: Remove MicroblazeCPUClass
>   i8254: Remove [KVM]PITClass
> 
>  hw/i386/kvm/i8254.c         | 17 ++---------------
>  hw/timer/i8254.c            | 16 ++--------------
>  include/hw/qdev-core.h      |  4 ++++
>  include/qom/cpu.h           |  4 ++++
>  include/qom/object.h        | 18 ++++++++++++++++++
>  qom/object.c                | 15 +++++++++++++++
>  target-arm/cpu-qom.h        | 20 --------------------
>  target-arm/cpu.c            | 16 +++++-----------
>  target-microblaze/cpu-qom.h | 20 --------------------
>  target-microblaze/cpu.c     | 13 ++++---------
>  10 files changed, 54 insertions(+), 89 deletions(-)
> 
> -- 
> 1.8.3.rc1.44.gb387c77.dirty