Re: [PATCH v2 3/4] gdb/progspace: add solib_ops pointer in program_space

[Simon Marchi <simon.marchi@efficios.com>]

On 6/11/25 2:43 PM, Simon Marchi wrote:
> On 6/11/25 2:14 PM, Guinevere Larsen wrote:
>>> @@ -1273,9 +1277,9 @@ solib_name_from_address (struct program_space *pspace, CORE_ADDR address)
>>>   bool
>>>   solib_keep_data_in_core (CORE_ADDR vaddr, unsigned long size)
>>>   {
>>> -  const solib_ops *ops = gdbarch_so_ops (current_inferior ()->arch ());
>>> +  const solib_ops *ops = current_program_space->solib_ops ();
>>>   -  if (ops->keep_data_in_core)
>>> +  if (ops != nullptr && ops->keep_data_in_core != nullptr)
>>
>> Can this function be called before the program space is fully setup?
>>
>> Otherwise I think we should either assume that it was set correctly,
>> or assert it. Better to be loud and easy to find the bug than
>> accidentally adding a regression in a hard-to-spot place.
>>
>> This goes to all other similar places where you check for ops !=
>> nullptr.
> 
> I don't really know for sure for all the methods.
> program_space::m_solib_ops is nullptr before you run the program, and I
> don't know off-hand which methods are reachable with an inferior that's
> not running yet.  I'll try to see if I can figure it out.

I think it would be safer to leave it like this.  There are some
functions in solib.c that are called with m_solib_ops == nullptr (when
the inferior isn't running), and returning early just makes sense there.

Speaking of that, I found out that I am missing an early return in the
newly added print_.  So with this patch, if you do "info shared" without
running the inferior first, GDB crashes.  I'll add it.

It's probable that some of the functions in solib.c are always called in
paths where the inferior is running, so there we could assert that ops
!= nullptr.  But figuring those out seems difficult, and I wouldn't be
that confident to get it right.

If for some reason the program space's solib_ops wasn't properly set up,
I think it would quickly show up in the test results.

Simon