[PATCH] Fix dwarf2_string_attr for -gsplit-dwarf

[Simon Marchi]

Hi Leszek,

On 2017-08-01 11:20, Leszek Swirski via gdb-patches wrote:
> The dwarf2_string_attr did not allow DW_FORM_GNU_str_index as a form 
> for
> string types. This manifested as null strings in the namespace_name
> lookup (replaced with "(anonymous namespace)") when debugging
> Fission-compiled code.

Thanks for the patch.  I am not very knowledgeable in that area, but I 
looked at the problem for a while and I think the change is good.  
DW_STRING (attr) is set for attribute values of this form in 
read_attribute_value.  Other functions like dwarf2_const_value_attr and 
dump_die_shallow read DW_STRING (attr) when dealing with an attribute of 
form DW_FORM_GNU_str_index as well.

If you think this will be a one-time contribution, we can merge the 
patch for you, and there is no need for copyright assignment for a 
simple patch like that.  However, if you'd like to contribute further to 
GDB, we can look into giving you write access, so you'll be able to push 
patches by yourself.  Let me know which one you prefer.

I just have some formatting comments about the patch itself.  No need 
for a v2, especially if we push for you, but just so you are aware of 
the GNU/GDB coding standards.

> gdb/doc/ChangeLog:

The ChangeLog entry for this patch will go in the gdb/ChangeLog file.

> 
> 	* dwarf2read.c: Fix dwarf2_string_attr to allow
> 	DW_FORM_GNU_str_index

The ChangeLog format has the function name in parentheses, for example:

   * dwarf2read.c (dwarf2_string_attr): Allow DW_FORM_GNU_strp_alt.

> ---
>  gdb/dwarf2read.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
> index 2c2ecda7fc..f5bed09116 100644
> --- a/gdb/dwarf2read.c
> +++ b/gdb/dwarf2read.c
> @@ -17623,7 +17623,8 @@ dwarf2_string_attr (struct die_info *die,
> unsigned int name, struct dwarf2_cu *c
>    if (attr != NULL)
>      {
>        if (attr->form == DW_FORM_strp || attr->form == 
> DW_FORM_line_strp
> -	  || attr->form == DW_FORM_string || attr->form == 
> DW_FORM_GNU_strp_alt)
> +	  || attr->form == DW_FORM_string || DW_FORM_GNU_str_index
> +          || attr->form == DW_FORM_GNU_strp_alt)

The indentation for this line should be one tab + two spaces (like the 
previous line).

Thanks,

Simon