Re: [PATCH] Fix DEMANGLE_COMPONENT_TEMPLATE_ARGLIST demangling (PR other/43838)

[Ian Lance Taylor <iant at google dot com>]

Jakub Jelinek <jakub@redhat.com> writes:

> 2010-06-09  Jakub Jelinek  <jakub@redhat.com>
>
> 	PR other/43838
> 	* cp-demangle.c (struct d_print_info): Add flush_count field.
> 	(d_print_init): Initialize it to 0.
> 	(d_print_flush): Increment it.
> 	(d_print_comp): If needed flush before appending ", ".  Only
> 	decrement dpi->len if no flushes happened during the recursive
> 	call.
> 	* testsuite/demangle-expected: Add a test for this.


> @@ -4047,12 +4051,18 @@ d_print_comp (struct d_print_info *dpi,
>        if (d_right (dc) != NULL)
>  	{
>  	  size_t len;
> +	  unsigned long int flush_count;
> +	  /* Make sure ", " isn't flushed by d_append_string, otherwise
> +	     dpi->len -= 2 wouldn't work.  */
> +	  if (dpi->len >= sizeof (dpi->buf) - 2)
> +	    d_print_flush (dpi);
>  	  d_append_string (dpi, ", ");
>  	  len = dpi->len;
> +	  flush_count = dpi->flush_count;
>  	  d_print_comp (dpi, d_right (dc));
>  	  /* If that didn't print anything (which can happen with empty
>  	     template argument packs), remove the comma and space.  */
> -	  if (dpi->len == len)
> +	  if (dpi->flush_count == flush_count && dpi->len == len)
>  	    dpi->len -= 2;
>  	}

I suppose this is OK, but it seems simpler and cleaner to just check
whether the d_print_comp will print anything before appending the
comma.  It seems like it should work to do

    struct demangle_component *right = d_right (dc);
    if (right != NULL && (d_left (right) != NULL || d_right (right) != NULL))
      {
        d_append_string (dpi, ", ");
        d_print_comp (dpi, right);
      }

Ian