[PATCH] Don't try to get the TIB address without an inferior

[Simon Marchi]

On 2020-03-06 12:06 p.m., Hannes Domani via gdb-patches wrote:
>  Am Freitag, 6. März 2020, 17:57:30 MEZ hat Simon Marchi <simark@simark.ca> Folgendes geschrieben:
> 
>> On 2020-03-06 11:50 a.m., Hannes Domani via gdb-patches wrote:
>>
>>> The target_get_tib_address call always fails in this case, and there is an
>>> error when changing the program with the file command:
>>>
>>> (gdb) file allocer64.exe
>>> Reading symbols from allocer64.exe...
>>> You can't do that when your target is `exec'
>>>
>>> Now it will skip this part, there is no need to rebase the executable without
>>> an inferior anyways.
>>>
>>> gdb/ChangeLog:
>>>
>>> 2020-03-06  Hannes Domani  <ssbssa@yahoo.de>
>>>
>>>      * windows-tdep.c (windows_solib_create_inferior_hook):
>>>      Check inferior_ptid.
>>> ---
>>>   gdb/windows-tdep.c | 3 ++-
>>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/gdb/windows-tdep.c b/gdb/windows-tdep.c
>>> index 4e5d8303ca..a3bacc2211 100644
>>> --- a/gdb/windows-tdep.c
>>> +++ b/gdb/windows-tdep.c
>>> @@ -843,7 +843,8 @@ windows_solib_create_inferior_hook (int from_tty)
>>>       }
>>>     CORE_ADDR tlb;
>>>     gdb_byte buf[8];
>>> -  if (target_get_tib_address (inferior_ptid, &tlb)
>>> +  if (inferior_ptid != null_ptid
>>> +      && target_get_tib_address (inferior_ptid, &tlb)
>>>         && !target_read_memory (tlb + peb_offset, buf, ptr_bytes))
>>>       {
>>>         CORE_ADDR peb = extract_unsigned_integer (buf, ptr_bytes, byte_order);
>>
>>
>> It won't really make much of a difference in practice, but I think it would be
>> appropriate to use "target_has_memory" for this condition.
> 
> I just tried it, but exec_target::has_memory() returns true, although no
> program is running:
> 
> (gdb) l
> 1153    bool
> 1154    exec_target::has_memory ()
> 1155    {
> 1156      /* We can provide memory if we have any file/target sections to read
> 1157         from.  */
> 1158      return (current_target_sections->sections
> 1159              != current_target_sections->sections_end);
> 1160    }
> 1161
> 1162    char *
> (gdb) p current_program_space->target_sections
> $4 = {
>   sections = 0x11f70630,
>   sections_end = 0x11f70710
> }
> 

Oh, right, perhaps target_has_execution then?