Re: [PATCH v3] md/define_c_enum: support value assignation

[Andrew Pinski <pinskia@gmail.com>]

On Tue, Aug 31, 2021 at 4:22 AM YunQiang Su <yunqiang.su@cipunited.com> wrote:
>
> Currently, the enums from define_c_enum and define_enum can only
> has values one by one from 0.
>
> In fact we can support the behaviour just like C, aka like
>   (define_enum "mips_isa" [(mips1 1) mips2 (mips32 32) mips32r2]),
> then we can get
>   enum mips_isa {
>     MIPS_ISA_MIPS1 = 1,
>     MIPS_ISA_MIPS2 = 2,
>     MIPS_ISA_MIPS32 = 32,
>     MIPS_ISA_MIPS32R2 = 33
>   };
>
> gcc/ChangeLog:
>         * read-md.c (md_reader::handle_enum): support value assignation.
>         * doc/md.texi: record define_c_enum value assignation support.
> ---
>  gcc/doc/md.texi |  4 ++++
>  gcc/read-md.c   | 21 +++++++++++++++++----
>  2 files changed, 21 insertions(+), 4 deletions(-)
>
> diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
> index f8047aefc..2b41cb7fb 100644
> --- a/gcc/doc/md.texi
> +++ b/gcc/doc/md.texi
> @@ -11074,6 +11074,8 @@ The syntax is as follows:
>  (define_c_enum "@var{name}" [
>    @var{value0}
>    @var{value1}
> +  (@var{value32} 32)
> +  @var{value33}
>    @dots{}
>    @var{valuen}
>  ])
> @@ -11086,6 +11088,8 @@ in @file{insn-constants.h}:
>  enum @var{name} @{
>    @var{value0} = 0,
>    @var{value1} = 1,
> +  @var{value32} = 32,
> +  @var{value33} = 33,
>    @dots{}
>    @var{valuen} = @var{n}
>  @};
> diff --git a/gcc/read-md.c b/gcc/read-md.c
> index bb419e0f6..0fbe924d1 100644
> --- a/gcc/read-md.c
> +++ b/gcc/read-md.c
> @@ -902,7 +902,8 @@ void
>  md_reader::handle_enum (file_location loc, bool md_p)
>  {
>    char *enum_name, *value_name;
> -  struct md_name name;
> +  unsigned int cur_value;
> +  struct md_name name, value;
>    struct enum_type *def;
>    struct enum_value *ev;
>    void **slot;
> @@ -928,6 +929,7 @@ md_reader::handle_enum (file_location loc, bool md_p)
>        *slot = def;
>      }
>
> +  cur_value = def->num_values;
>    require_char_ws ('[');
>
>    while ((c = read_skip_spaces ()) != ']')
> @@ -937,8 +939,18 @@ md_reader::handle_enum (file_location loc, bool md_p)
>           error_at (loc, "unterminated construct");
>           exit (1);
>         }
> -      unread_char (c);
> -      read_name (&name);
> +      if (c == '(')
> +       {
> +         read_name (&name);
> +         read_name (&value);
> +         require_char_ws (')');
> +         cur_value = atoi(value.string);

We really should be avoiding adding atoi.  Yes there are uses already
in the source but https://gcc.gnu.org/PR44574 exists to track those
uses.

Thanks,
Andrew


> +       }
> +      else
> +       {
> +         unread_char (c);
> +         read_name (&name);
> +       }
>
>        ev = XNEW (struct enum_value);
>        ev->next = 0;
> @@ -954,11 +966,12 @@ md_reader::handle_enum (file_location loc, bool md_p)
>           ev->name = value_name;
>         }
>        ev->def = add_constant (get_md_constants (), value_name,
> -                             md_decimal_string (def->num_values), def);
> +                             md_decimal_string (cur_value), def);
>
>        *def->tail_ptr = ev;
>        def->tail_ptr = &ev->next;
>        def->num_values++;
> +      cur_value++;
>      }
>  }
>
> --
> 2.30.2
>