Re: [PATCH 01/14] include/hw: add helpers for defining versioned machine types

[Thomas Huth]

On 01/05/2024 20.27, Daniel P. Berrangé wrote:
> The various targets which define versioned machine types have
> a bunch of obfuscated macro code for defining unique function
> and variable names using string concatenation.
>
> This addes a couple of helpers to improve the clarity of such
> code macro.
>
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
>   include/hw/boards.h | 166 ++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 166 insertions(+)
>
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index 2fa800f11a..47ca450fca 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -414,6 +414,172 @@ struct MachineState {
>       struct NumaState *numa_state;
>   };
>   
> +/*
> + * The macros which follow are intended to facilitate the
> + * definition of versioned machine types, using a somewhat
> + * similar pattern across targets:

I'd suggest to add a sentence at the end saying something like this: "For 
example, to create the macro for setting up a versioned "virt" machine could 
look like this:" (otherwise it's not immediately clear whether the example 
is about only the "macros which follow" or whether it's about how to set up 
a machine type)

> + *  #define DEFINE_VIRT_MACHINE_IMPL(latest, ...) \
> + *      static void MACHINE_VER_SYM(class_init, virt, __VA_ARGS__)( \
> + *          ObjectClass *oc, \
> + *          void *data) \
> + *      { \
> + *          MachineClass *mc = MACHINE_CLASS(oc); \
> + *          MACHINE_VER_SYM(options, virt, __VA_ARGS__)(mc); \
> + *          mc->desc = "QEMU " MACHINE_VER_STR(__VA_ARGS__) " Virtual 
> Machine"; \
> + *          if (latest) { \
> + *              mc->alias = "virt"; \
> + *          } \
> + *      } \
> + *      static const TypeInfo MACHINE_VER_SYM(info, virt, __VA_ARGS__) = { \
> + *          .name = MACHINE_VER_TYPE_NAME("virt", __VA_ARGS__), \
> + *          .parent = TYPE_VIRT_MACHINE, \
> + *          .class_init = MACHINE_VER_SYM(class_init, virt, __VA_ARGS__), \
> + *      }; \
> + *      static void MACHINE_VER_SYM(register, virt, __VA_ARGS__)(void) \
> + *      { \
> + *          type_register_static(&MACHINE_VER_SYM(info, virt, __VA_ARGS__)); \
> + *      } \
> + *      type_init(MACHINE_VER_SYM(register, virt, __VA_ARGS__));
> + *
> + * Following this, one (or more) helpers can be added for
> + * whichever scenarios need to be catered for with a machine:
> + *
> + *  // Normal 2 digit, marked as latest eg 'virt-9.0'
> + *  #define DEFINE_VIRT_MACHINE_LATEST(major, minor) \
> + *      DEFINE_VIRT_MACHINE_IMPL(true, major, minor)
> + *
> + *  // Normal 2 digit eg 'virt-9.0'
> + *  #define DEFINE_VIRT_MACHINE(major, minor) \
> + *      DEFINE_VIRT_MACHINE_IMPL(false, major, minor)
> + *
> + *  // Bugfix 3 digit  eg 'virt-9.0.1'
> + *  #define DEFINE_VIRT_MACHINE_BUGFIX(major, minor, micro) \
> + *      DEFINE_VIRT_MACHINE_IMPL(false, major, minor, micro)
> + *
> + *  // Tagged 2 digit  eg 'virt-9.0-extra'
> + *  #define DEFINE_VIRT_MACHINE_TAGGED(major, minor, tag) \
> + *      DEFINE_VIRT_MACHINE_IMPL(false, major, minor, _, tag)
> + *
> + *  // Tagged bugffix 2 digit  eg 'virt-9.0.1-extra'

s/bugffix/bugfix/

> + *  #define DEFINE_VIRT_MACHINE_TAGGED(major, minor, micro, tag) \
> + *      DEFINE_VIRT_MACHINE_IMPL(false, major, minor, micro, _, tag)
> + */

I'd suggest to add a separate comment for the macro below, explaining that 
it is supposed to be used with __VA_ARGS__ to pick a certain other macro 
depending on the amount of entries in __VA_ARGS__.

> +#define _MACHINE_VER_PICK(x1, x2, x3, x4, x5, x6, ...) x6
> +
> +/*
> + * Construct a human targetted machine version string.

s/targetted/targeted/ according to my spell checker ?

Apart from the nits:
Reviewed-by: Thomas Huth <thuth@redhat.com>

 Thomas