Re: [PATCH Rust front-end v2 01/37] Use DW_ATE_UTF for the Rust 'char' type

[Jason Merrill <jason@redhat.com>]

On 8/24/22 04:59, herron.philip@googlemail.com wrote:
> From: Tom Tromey <tom@tromey.com>
> 
> The Rust 'char' type should use the DWARF DW_ATE_UTF encoding.

The DWARF changes are OK.

> ---
>   gcc/dwarf2out.cc | 23 ++++++++++++++++++++++-
>   1 file changed, 22 insertions(+), 1 deletion(-)
> 
> diff --git a/gcc/dwarf2out.cc b/gcc/dwarf2out.cc
> index e3920c898f5..a8bccbabca4 100644
> --- a/gcc/dwarf2out.cc
> +++ b/gcc/dwarf2out.cc
> @@ -5600,6 +5600,16 @@ is_fortran (const_tree decl)
>     return is_fortran ();
>   }
>   
> +/* Return TRUE if the language is Rust.  */
> +
> +static inline bool
> +is_rust ()
> +{
> +  unsigned int lang = get_AT_unsigned (comp_unit_die (), DW_AT_language);
> +
> +  return lang == DW_LANG_Rust || lang == DW_LANG_Rust_old;
> +}
> +
>   /* Return TRUE if the language is Ada.  */
>   
>   static inline bool
> @@ -13231,7 +13241,11 @@ base_type_die (tree type, bool reverse)
>   	}
>         if (TYPE_STRING_FLAG (type))
>   	{
> -	  if (TYPE_UNSIGNED (type))
> +	  if ((dwarf_version >= 4 || !dwarf_strict)
> +	      && is_rust ()
> +	      && int_size_in_bytes (type) == 4)
> +	    encoding = DW_ATE_UTF;
> +	  else if (TYPE_UNSIGNED (type))
>   	    encoding = DW_ATE_unsigned_char;
>   	  else
>   	    encoding = DW_ATE_signed_char;
> @@ -25201,6 +25215,13 @@ gen_compile_unit_die (const char *filename)
>       }
>     else if (strcmp (language_string, "GNU F77") == 0)
>       language = DW_LANG_Fortran77;
> +  else if (strcmp (language_string, "GNU Rust") == 0)
> +    {
> +      if (dwarf_version >= 5 || !dwarf_strict)
> +	language = DW_LANG_Rust;
> +      else
> +	language = DW_LANG_Rust_old;
> +    }
>     else if (dwarf_version >= 3 || !dwarf_strict)
>       {
>         if (strcmp (language_string, "GNU Ada") == 0)