Re: [RFC] design question re: watchpoint target methods

[David Daney <ddaney@caviumnetworks.com>]

Joel Brobecker wrote:
> Hello everyone,
> 
> Jan said:
>> [...] I find the single functionality being split into two target
>> functions (to_stopped_by_watchpoint and to_stopped_data_address) to be
>> confusing.  Chose a new name to easily be able to keep the old
>> deprecated implementations working until its host maintainers can get
>> to update them as I cannot even compile some of the host files.
> 
> I tend to agree because I do not know of any reason why this separation
> would be needed.  Any reason why we should reject Jan's suggestion to
> have a single target operation instead of two? His proposal is to mark
> the following methods as deprecated:
> 
>     int (*to_stopped_by_watchpoint) (void);
>     int (*to_stopped_data_address) (struct target_ops *, CORE_ADDR *);
> 
> And to replace them by by a new operation:
> 
>     enum stopped_by_watchpoint (*to_thread_stopped_by_watchpoint)
>         (ptid_t ptid, CORE_ADDR *data_address_p);
> 
> Actually, I think that all target_ops operations should take a struct
> target_ops parameter, even if not needed, at least for consistency, but
> also to facilitate transitions if this parameter ever becomes needed
> later on.
> 
> One difference in the new operation is that it is now explicitly
> applicable to a specific ptid rather than being implicitly applicable
> to the current_ptid.
> 
> enum stopped_by_watchpoint is proposed to be:
>> +enum stopped_by_watchpoint
>> +  {
>> +    stopped_by_watchpoint_no,
>> +    stopped_by_watchpoint_yes_address_unknown,
>> +    stopped_by_watchpoint_yes_address_known
>> +  };

FWIW, I think it would be a good change.

I am somewhat ignorant about the namespace of ptid, but in the presence 
of multi-process debugging many of the target operations need to 
differentiate for which process the operation is intended.  I would hope 
that ptid would serve that purpose.

Certainly  mips-linux-nat.c would be affected by such a change.


Thanks,
David Daney