[PATCH, PR 57195] Allow mode iterators inside angle brackets

[Richard Sandiford]

Michael Collison <michael.collison@linaro.org> writes:
> This patch allow mode iterators inside angle brackets in machine
> description files. I discovered the issue when attempting to use
> iterators on match_operand's as follows:
>
> match_operand:<VW:V_widen> 0 "s_register_operand" "=w")
>
> The function 'read_name' is nor properly handling ':' inside angle brackets.
>
> Bootstrapped on arm-linux.

Sorry for the slow review.

> diff --git a/gcc/read-md.c b/gcc/read-md.c
> index 9f158ec..0171fb0 100644
> --- a/gcc/read-md.c
> +++ b/gcc/read-md.c
> @@ -399,17 +399,25 @@ read_name (struct md_name *name)
>   {
>     int c;
>     size_t i;
> +  bool in_angle_bracket;
>
>     c = read_skip_spaces ();
>
>     i = 0;
> +  in_angle_bracket = false;
>     while (1)
>       {
> +      if (c == '<')
> +    in_angle_bracket = true;
> +
> +      if (c == '>')
> +    in_angle_bracket = false;
> +
>         if (c == ' ' || c == '\n' || c == '\t' || c == '\f' || c == '\r'
>         || c == EOF)
>       break;
> -      if (c == ':' || c == ')' || c == ']' || c == '"' || c == '/'
> -      || c == '(' || c == '[')
> +      if (((c == ':') and (!in_angle_bracket)) || c == ')' || c == ']'
> +      || c == '"' || c == '/' || c == '(' || c == '[')
>       {
>         unread_char (c);
>         break;

I think we should have a nesting depth rather than a boolean.
It also seems more natural to skip the final "if" statement above when
inside an angle bracket, rather than treating ':' as a special case.
(We'd still break at the end of the line in the case of a missing '>',
so the error reporting shouldn't be too bad.)

I suppose logically '>' with a nesting depth of 0 should also break
the loop.

Thanks for fixing this.

Richard