Re: Display of read/access watchpoints when HAVE_NONSTEPPABLE_WATCHPOINT

[Orjan Friberg <orjan dot friberg at axis dot com>]

Eli Zaretskii wrote:
> However, it seems to me that the right thing to do is to fix the cited
> code in bpstat_stop_status (and perhaps elsewhere in breakpoint.c) to
> DTRT for the test program posted by Orjan, since it clearly should
> work with i386 as well, and since this specific failure of GDB has
> nothing to do with read-only vs read-write watchpoints.

The test program (repeated below) *does* work for i386 (though I didn't 
say that), because it also stops when foo is written (thus updating the 
value of foo when watchpoint_check is called), so by the time it stops 
when the second read happens the value hasn't changed since the last 
time and GDB decides it's a valid hit.

  volatile int foo = 0;
  int a;

  a = foo;
  foo = 1;
  a = foo;

Question is how to fix this (comments are most welcome):

1. Add a check if the target cannot set "pure" read watchpoints to the 
b->type == bp_read_watchpoint check at WP_VALUE_CHANGED (my 
interpretation of Eli's suggestion).

or

2. Somehow don't update the value in watchpoint_check when it's a false 
hit.  (Then the b->type == bp_read_watchpoint check at WP_VALUE_CHANGED 
isn't needed.)

or

3. Add some distinction between "wanted watchpoint type" and "actual 
watchpoint type".

--
Orjan Friberg
Axis Communications