Re: [PATCH v4] RISC-V: Add -march=help for gas

[Kito Cheng <kito.cheng@gmail.com>]

LGTM :)

On Fri, Feb 23, 2024 at 2:18 PM Hau Hsu <hau.hsu@sifive.com> wrote:
>
> Use -march=help for gas to print all supported extensions and versions.
>
> Here is part of the output of `as -march=help`:
> All available -march extensions for RISC-V:
>         e                                       1.9
>         i                                       2.1, 2.0
>         m                                       2.0
>         a                                       2.1, 2.0
>         f                                       2.2, 2.0
>         d                                       2.2, 2.0
>         q                                       2.2, 2.0
>         c                                       2.0
>         v                                       1.0
>         h                                       1.0
>         zicbom                                  1.0
>         zicbop                                  1.0
>         ...
>
> This patch assumes that the supported extensions with the same versions
> are listed together. For example:
> static struct riscv_supported_ext riscv_supported_std_ext[] =
> {
>   ...
>   {"i",         ISA_SPEC_CLASS_20191213,        2, 1, 0 },
>   {"i",         ISA_SPEC_CLASS_20190608,        2, 1, 0 },
>   {"i",         ISA_SPEC_CLASS_2P2,             2, 0, 0 },
>   ...
> };
>
> For the "i" extension, 2.1.0 with different spec class are listed together.
> This patch records the previous printed extension and version.  If the
> current extension and version are the same as the previous one, skip
> printing.
> ---
>  bfd/ChangeLog         |  9 ++++++
>  bfd/elfxx-riscv.c     | 64 +++++++++++++++++++++++++++++++++++++++++++
>  bfd/elfxx-riscv.h     |  3 ++
>  gas/ChangeLog         |  4 +++
>  gas/config/tc-riscv.c |  6 ++++
>  5 files changed, 86 insertions(+)
>
> diff --git a/bfd/ChangeLog b/bfd/ChangeLog
> index 97d0c585a56..66572927998 100644
> --- a/bfd/ChangeLog
> +++ b/bfd/ChangeLog
> @@ -1,3 +1,12 @@
> +2024-02-21 Hau Hsu  <hau.hsu@sifive.com>
> +
> +       * elfxx-riscv.h (riscv_print_extensions): New declaration.
> +       * elfxx-riscv.c (riscv_print_extensions): New function. Print
> +       available extensions and versions.
> +       (riscv_same_extension_version): New function.
> +       (riscv_same_extension_diff_version): New function.
> +       (riscv_valid_ext): New function.
> +
>  2024-01-15  Nick Clifton  <nickc@redhat.com>
>
>         * 2.42 branch point.
> diff --git a/bfd/elfxx-riscv.c b/bfd/elfxx-riscv.c
> index 9a121b47121..108e26d5b30 100644
> --- a/bfd/elfxx-riscv.c
> +++ b/bfd/elfxx-riscv.c
> @@ -2051,6 +2051,70 @@ riscv_set_default_arch (riscv_parse_subset_t *rps)
>      }
>  }
>
> +static
> +bool riscv_same_extension_version(
> +  const struct riscv_supported_ext* ext1,
> +  const struct riscv_supported_ext* ext2)
> +{
> +  return (strcmp(ext1->name, ext2->name) == 0
> +          && ext1->major_version == ext2->major_version
> +          && ext1->minor_version == ext2->minor_version);
> +}
> +
> +static
> +bool riscv_same_extension_diff_version(
> +  const struct riscv_supported_ext* ext1,
> +  const struct riscv_supported_ext* ext2)
> +{
> +  return (strcmp(ext1->name, ext2->name) == 0
> +          && !(ext1->major_version == ext2->major_version
> +               && ext1->minor_version == ext2->minor_version));
> +}
> +
> +static
> +bool riscv_valid_ext(const struct riscv_supported_ext *ext)
> +{
> +  return (ext->isa_spec_class != ISA_SPEC_CLASS_NONE
> +          && ext->major_version != RISCV_UNKNOWN_VERSION
> +          && ext->minor_version != RISCV_UNKNOWN_VERSION);
> +}
> +
> +void riscv_print_extensions(void)
> +{
> +  /* Record the previous pritned extension.
> +     Print the current one if they are not the same.  */
> +  const struct riscv_supported_ext *cur = NULL, *prev = NULL;
> +
> +  int i, j;
> +  printf ("All available -march extensions for RISC-V:");
> +  for (i = 0; riscv_all_supported_ext[i] != NULL; i++)
> +    {
> +      const struct riscv_supported_ext *exts = riscv_all_supported_ext[i];
> +      prev = NULL;
> +      for (j = 0; exts[j].name != NULL; j++)
> +        {
> +          cur = &exts[j];
> +          if (!riscv_valid_ext (cur))
> +            continue;
> +
> +          if (prev && riscv_same_extension_version (prev, cur))
> +            continue;
> +
> +          if (!prev || !riscv_same_extension_diff_version (prev, cur))
> +            {
> +              printf("\n\t%-40s%d.%d", cur->name, cur->major_version, cur->minor_version);
> +              prev = &exts[j];
> +            }
> +          else
> +            {
> +              printf(", %d.%d", cur->major_version, cur->minor_version);
> +              prev = &exts[j];
> +            }
> +        }
> +    }
> +  printf ("\n");
> +}
> +
>  /* Function for parsing ISA string.
>
>     Return Value:
> diff --git a/bfd/elfxx-riscv.h b/bfd/elfxx-riscv.h
> index ae4cbee7bc3..f3710ec7fab 100644
> --- a/bfd/elfxx-riscv.h
> +++ b/bfd/elfxx-riscv.h
> @@ -121,6 +121,9 @@ riscv_multi_subset_supports (riscv_parse_subset_t *, enum riscv_insn_class);
>  extern const char *
>  riscv_multi_subset_supports_ext (riscv_parse_subset_t *, enum riscv_insn_class);
>
> +extern void
> +riscv_print_extensions(void);
> +
>  extern void
>  bfd_elf32_riscv_set_data_segment_info (struct bfd_link_info *, int *);
>  extern void
> diff --git a/gas/ChangeLog b/gas/ChangeLog
> index 88e61083c44..cebd9d94ae5 100644
> --- a/gas/ChangeLog
> +++ b/gas/ChangeLog
> @@ -1,3 +1,7 @@
> +2024-02-21 Hau Hsu  <hau.hsu@sifive.com>
> +       * gas/config/tc-riscv.c (md_parse_option): Parse 'help' keyword in
> +       march to print available extensions and versions.
> +
>  2024-02-19 Will Hawkins  <hawkinsw@obs.cr>
>
>         * config/tc-bpf.c (parse_expression): Change switch to if so that
> diff --git a/gas/config/tc-riscv.c b/gas/config/tc-riscv.c
> index a4161420128..e0910f59157 100644
> --- a/gas/config/tc-riscv.c
> +++ b/gas/config/tc-riscv.c
> @@ -4034,6 +4034,12 @@ md_parse_option (int c, const char *arg)
>    switch (c)
>      {
>      case OPTION_MARCH:
> +      /* List all avaiable archs. */
> +      if (strcmp (arg, "help") == 0)
> +        {
> +          riscv_print_extensions();
> +          exit (EXIT_SUCCESS);
> +        }
>        default_arch_with_ext = arg;
>        break;
>
> --
> 2.31.1
>