Re: [PATCH 17/20] Change die_info methods to check the attribute's form

[Simon Marchi <simark@simark.ca>]

On 2020-03-28 3:22 p.m., Tom Tromey wrote:
> This changes two die_info methods to check the form of the attribute
> before using it.
> 
> 2020-03-28  Tom Tromey  <tom@tromey.com>
> 
> 	* dwarf2/die.h (struct die_info) <addr_base, ranges_base>: Check
> 	the attribute's form.
> ---
>  gdb/ChangeLog    |  5 +++++
>  gdb/dwarf2/die.h | 14 ++++++++------
>  2 files changed, 13 insertions(+), 6 deletions(-)
> 
> diff --git a/gdb/dwarf2/die.h b/gdb/dwarf2/die.h
> index 5522ebdf311..37f83a45a50 100644
> --- a/gdb/dwarf2/die.h
> +++ b/gdb/dwarf2/die.h
> @@ -39,11 +39,12 @@ struct die_info
>    gdb::optional<ULONGEST> addr_base ()
>    {
>      for (unsigned i = 0; i < num_attrs; ++i)
> -      if (attrs[i].name == DW_AT_addr_base
> -	  || attrs[i].name == DW_AT_GNU_addr_base)
> +      if ((attrs[i].name == DW_AT_addr_base
> +	   || attrs[i].name == DW_AT_GNU_addr_base)
> +	  && attrs[i].form_is_unsigned ())
>  	{
>  	  /* If both exist, just use the first one.  */
> -	  return DW_UNSND (&attrs[i]);
> +	  return attrs[i].get_unsigned ();
>  	}
>      return gdb::optional<ULONGEST> ();
>    }

A bit like in the previous patch, if there is a DW_AT_addr_base, but it's
not of the right form, I think we should emit a warning saying that we ignore
it, instead of just ignoring it silently.

That's probably out of the scope of this patch though, but I'm just noting it.

Simon