struct address_space *aspace2,
CORE_ADDR addr2);
+static int watchpoint_locations_match (struct bp_location *loc1,
+ struct bp_location *loc2);
+
static void breakpoints_info (char *, int);
static void breakpoint_1 (int, int);
watchpoints. It's not clear that it's necessary... */
&& bpt->owner->disposition != disp_del_at_next_stop)
{
- val = target_insert_watchpoint (bpt->address,
+ val = target_insert_watchpoint (bpt->address,
bpt->length,
bpt->watchpoint_type);
- bpt->inserted = (val != -1);
+
+ /* If trying to set a read-watchpoint, and it turns out it's not
+ supported, try emulating one with an access watchpoint. */
+ if (val == 1 && bpt->watchpoint_type == hw_read)
+ {
+ struct bp_location *loc, **loc_temp;
+
+ /* But don't try to insert it, if there's already another
+ hw_access location that would be considered a duplicate
+ of this one. */
+ ALL_BP_LOCATIONS (loc, loc_temp)
+ if (loc != bpt
+ && loc->watchpoint_type == hw_access
+ && watchpoint_locations_match (bpt, loc))
+ {
+ bpt->duplicate = 1;
+ bpt->inserted = 1;
+ bpt->target_info = loc->target_info;
+ bpt->watchpoint_type = hw_access;
+ val = 0;
+ break;
+ }
+
+ if (val == 1)
+ {
+ val = target_insert_watchpoint (bpt->address,
+ bpt->length,
+ hw_access);
+ if (val == 0)
+ bpt->watchpoint_type = hw_access;
+ }
+ }
+
+ bpt->inserted = (val == 0);
}
else if (bpt->owner->type == bp_catchpoint)
case WP_VALUE_CHANGED:
if (b->type == bp_read_watchpoint)
{
- /* Don't stop: read watchpoints shouldn't fire if
- the value has changed. This is for targets
- which cannot set read-only watchpoints. */
- bs->print_it = print_it_noop;
- bs->stop = 0;
+ /* There are two cases to consider here:
+
+ 1. we're watching the triggered memory for reads.
+ In that case, trust the target, and always report
+ the watchpoint hit to the user. Even though
+ reads don't cause value changes, the value may
+ have changed since the last time it was read, and
+ since we're not trapping writes, we will not see
+ those, and as such we should ignore our notion of
+ old value.
+
+ 2. we're watching the triggered memory for both
+ reads and writes. There are two ways this may
+ happen:
+
+ 2.1. this is a target that can't break on data
+ reads only, but can break on accesses (reads or
+ writes), such as e.g., x86. We detect this case
+ at the time we try to insert read watchpoints.
+
+ 2.2. otherwise, the target supports read
+ watchpoints, but, the user set an access or write
+ watchpoint watching the same memory as this read
+ watchpoint.
+
+ If we're watching memory writes as well as reads,
+ ignore watchpoint hits when we find that the
+ value hasn't changed, as reads don't cause
+ changes. This still gives false positives when
+ the program writes the same value to memory as
+ what there was already in memory (we will confuse
+ it for a read), but it's much better than
+ nothing. */
+
+ int other_write_watchpoint = 0;
+
+ if (bl->watchpoint_type == hw_read)
+ {
+ struct breakpoint *other_b;
+
+ ALL_BREAKPOINTS (other_b)
+ if ((other_b->type == bp_hardware_watchpoint
+ || other_b->type == bp_access_watchpoint)
+ && (other_b->watchpoint_triggered
+ == watch_triggered_yes))
+ {
+ other_write_watchpoint = 1;
+ break;
+ }
+ }
+
+ if (other_write_watchpoint
+ || bl->watchpoint_type == hw_access)
+ {
+ /* We're watching the same memory for writes,
+ and the value changed since the last time we
+ updated it, so this trap must be for a write.
+ Ignore it. */
+ bs->print_it = print_it_noop;
+ bs->stop = 0;
+ }
}
break;
case WP_VALUE_NOT_CHANGED:
static int
watchpoint_locations_match (struct bp_location *loc1, struct bp_location *loc2)
{
+ /* Note that this checks the owner's type, not the location's. In
+ case the target does not support read watchpoints, but does
+ support access watchpoints, we'll have bp_read_watchpoint
+ watchpoints with hw_access locations. Those should be considered
+ duplicates of hw_read locations. The hw_read locations will
+ become hw_access locations later. */
return (loc1->owner->type == loc2->owner->type
&& loc1->pspace->aspace == loc2->pspace->aspace
&& loc1->address == loc2->address
/* For the sake of should_be_inserted.
Duplicates check below will fix up this later. */
loc2->duplicate = 0;
+
+ /* Read watchpoint locations are switched to
+ access watchpoints, if the former are not
+ supported, but the latter are. */
+ if (is_hardware_watchpoint (old_loc->owner))
+ {
+ gdb_assert (is_hardware_watchpoint (loc2->owner));
+ loc2->watchpoint_type = old_loc->watchpoint_type;
+ }
+
if (loc2 != old_loc && should_be_inserted (loc2))
{
loc2->inserted = 1;
projects / deliverable / binutils-gdb.git / blobdiff