Re: Display of read/access watchpoints when HAVE_NONSTEPPABLE_WATCHPOINT

[Orjan Friberg <orjan.friberg@axis.com>]

Orjan Friberg wrote:
> 
> 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).

On second thought, this actually is no good for a target which *can* set 
pure read watchpoints.  If there's both a watch and an rwatch on a 
variable that is written, we'll get a false read watchpoint hit.

For the sake of argument, say that the implementation is called 
TARGET_CANNOT_SET_PURE_READ_WATCHPOINTS (the i386 would return 1, my 
target would return 0).  The check for a read watchpoint would then be

   case WP_VALUE_CHANGED:
     if (b->type == bp_read_watchpoint
         && TARGET_CANNOT_SET_PURE_READ_WATCHPOINTS)
     /* Don't stop.  */

For i386, nothing would change.  For my target, the following would 
happen (foo is watched and rwatched, original value != 0):

   a = foo;   /* foo read; read watchpoint hits.  */
   foo = 1;   /* foo written; write watchpoint hits, read watchpoint
                 hits incorrectly.  */

-- 
Orjan Friberg
Axis Communications