What to do with threads?

[Andrew Cagney <ac131313@redhat.com>]

Hello,

To put it simply, how can one fix this:

static CORE_ADDR
d10v_read_pc (ptid_t ptid)
{
   ....
   read_register (PC_REGNUM);
   ....
}

There are problems at many levels.  Off the top of my head:

- ptid can identify a thread and/or a LWP
- there sometimes isn't even a thread and/or a LWP
- the selected and current thread both fight over the same global data 
structures
- long long term, an objective is to have gdb debug multiple processes / 
  ISAs
- so long term that it is probably funny, an objective is to have gdb 
debugging multiple targets

I think we've fought the frame battle and won (the casualties will take 
ages to recover mind :-), the thread battle, I think, is next.

Andrew