Re: [Qemu-devel] [PATCH for-1.5?] target-ppc: Drop unnecessary dynamic cast in ppc_env_get_cpu()

[Andreas Färber]

[resending after bounce]

Am 10.05.2013 17:06, schrieb Anthony Liguori:
> Andreas Färber <address@hidden> writes:
> 
>> A transition from CPUPPCState to PowerPCCPU can be considered safe,
>> just like PowerPCCPU::env access in the opposite direction.
>>
>> This should slightly improve interrupt performance.
>>
>> Reported-by: Anthony Liguori <address@hidden>
>> Signed-off-by: Andreas Färber <address@hidden>
> 
> Another option would be to leave it and do something like:
> 
> diff --git a/qom/object.c b/qom/object.c
> index 75e6aac..cba1d88 100644
> --- a/qom/object.c
> +++ b/qom/object.c
> @@ -126,8 +126,13 @@ static TypeImpl *type_register_internal(const TypeInfo 
> *info)
>  
>  TypeImpl *type_register(const TypeInfo *info)
>  {
> +    TypeImpl *impl;
> +
>      assert(info->parent);
> -    return type_register_internal(info);
> +    impl = type_register_internal(info);
> +    g_free(impl->name);
> +    impl->name = info->name;
> +    return impl;
>  }
>  
>  TypeImpl *type_register_static(const TypeInfo *info)
> @@ -449,10 +490,16 @@ Object *object_dynamic_cast_assert(Object *obj, const 
> char *typename)
>  ObjectClass *object_class_dynamic_cast(ObjectClass *class,
>                                         const char *typename)
>  {
> -    TypeImpl *target_type = type_get_by_name(typename);
> +    TypeImpl *target_type;
>      TypeImpl *type = class->type;
>      ObjectClass *ret = NULL;
>  
> +    if (type->name == typename) {
> +        return class;
> +    }
> +
> +    target_type = type_get_by_name(typename);
> +
>      if (!target_type) {
>          /* target class type unknown, so fail the cast */
>          return NULL;
> 
> Which makes casting an object to it's concrete class free.

Doesn't help here since concrete class is POWER7_v2.1-ppc64-cpu whereas
we're casting to ppc64-cpu, with two-level hierarchy by now:
POWER7_v2.1 -> POWER7 -> ppc64 -> device -> object.

Regards,
Andreas

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