Re: [PATCH v2 3/8] machine: Print supported CPU models instead of typenames

[Gavin Shan]

On 7/27/23 09:08, Richard Henderson wrote:
> On 7/25/23 17:32, Gavin Shan wrote:
> > -static const char *q800_machine_valid_cpu_types[] = {
> > +static const char * const q800_machine_valid_cpu_types[] = {
> >       M68K_CPU_TYPE_NAME("m68040"),
> >       NULL
> >   };
> > +static const char * const q800_machine_valid_cpu_models[] = {
> > +    "m68040",
> > +    NULL
> > +};
>
> I really don't like this replication.

Right, it's going to be lots of replications, but gives much flexibility.
There are 21 targets and we don't have fixed pattern for the mapping between
CPU model name and CPU typename. I'm summarizing the used patterns like below.

  1 All CPU model names are mappinged to fixed CPU typename;
  2 CPU model name is same to CPU typename;
  3 CPU model name is alias to CPU typename;
  4 CPU model name is prefix of CPU typename;

  Target         Categories    suffix-of-CPU-typename
  -------------------------------------------------------
  alpha          -234          -alpha-cpu
  arm            ---4          -arm-cpu
  avr            -2--
  cris           --34          -cris-cpu
  hexagon        ---4          -hexagon-cpu
  hppa           1---
  i386           ---4          -i386-cpu
  loongarch      -2-4          -loongarch-cpu
  m68k           ---4          -m68k-cpu
  microblaze     1---
  mips           ---4          -mips64-cpu  -mips-cpu
  nios2          1---
  openrisc       ---4          -or1k-cpu
  ppc            --34          -powerpc64-cpu  -powerpc-cpu
  riscv          ---4          -riscv-cpu
  rx             -2-4          -rx-cpu
  s390x          ---4          -s390x-cpu
  sh4            --34          -superh-cpu
  sparc          -2--
  tricore        ---4          -tricore-cpu
  xtensa         ---4          -xtensa-cpu

There are several options as below. Please let me know which one or something
else is the best.

(a) Keep what we have and use mc->valid_{cpu_types, cpu_models}[] to track
the valid CPU typenames and CPU model names.

(b) Introduce CPUClass::model_name_by_typename(). Every target has their own
implementation to convert CPU typename to CPU model name. The CPU model name
is parsed from mc->valid_cpu_types[i].

    char *CPUClass::model_by_typename(const char *typename);

(c) As we discussed before, use mc->valid_cpu_type_suffix and 
mc->valid_cpu_models
because the CPU type check is currently needed by target arm/m68k/riscv where we
do have fixed pattern to convert CPU model names to CPU typenames. The CPU 
typename
is comprised of CPU model name and suffix. However, it won't be working when 
the CPU
type check is required by other target where we have patterns other than this.

Thanks,
Gavin