2011-01-11 Sergio Durigan Junior <sergiodj@linux.vnet.ibm.com>

	    Thiago Jung Bauermann  <bauerman@br.ibm.com>

	Implement support for PowerPC BookE ranged watchpoints.

gdb/
	* breakpoint.h
	(struct breakpoint_ops) <resources_needed>: New method.
	Initialize to NULL in all existing breakpoint_ops instances.
	(struct breakpoint) <exact>: New field.
	(target_exact_watchpoints): Declare external global.
	* breakpoint.c (target_exact_watchpoints): New global flag.
	(update_watchpoint): Set b->type to bp_hardware_watchpoint and
	b->enable_state to bp_enabled before calling
	hw_watchpoint_used_count.
	(hw_watchpoint_used_count): Iterate over all bp_locations in a
	watchpoint.  Call breakpoint's breakpoint_ops.resources_needed
	if available.
	(insert_watchpoint, remove_watchpoint): Use fixed length of 1 byte
	if the watchpoint is exact.
	(resources_needed_watchpoint): New function.
	(watchpoint_breakpoint_ops): Add resources_needed_watchpoint.
	(watch_command_1): Set b->exact if the user asked for an exact
	watchpoint and one can be set.
	(can_use_hardware_watchpoint): Add exact_watchpoints argument.
	Pass fixed length of 1 to target_region_ok_for_hw_watchpoint if
	the user asks for an exact watchpoint and one can be set.  Return
	number of needed debug registers to watch the expression.
	* gdbtypes.c (is_scalar_type): New function, based on
	valprint.c:scalar_type_p.
	(is_scalar_type_recursive): New function.
	* gdbtypes.h (is_scalar_type_recursive): Declare.
	* ppc-linux-nat.c (ppc_linux_region_ok_for_hw_watchpoint): Always
	handle regions when ranged watchpoints are available.
	(create_watchpoint_request): New function.
	(ppc_linux_insert_watchpoint, ppc_linux_remove_watchpoint): Use
	create_watchpoint_request.
	* rs6000-tdep.c (show_powerpc_exact_watchpoints): New function.
	(_initialize_rs6000_tdep): Add `exact-watchpoints' boolean to the
	`set powerpc' and `show powerpc' commands.
	* target.h (struct target_ops) <to_region_ok_for_hw_watchpoint>:
	Mention documentation comment in the target macro.
	(target_region_ok_for_hw_watchpoint): Document return value.

gdb/doc/
	* gdb.texinfo (PowerPC Embedded): Document ranged watchpoints and
	the "set powerpc exact-watchpoints" flag.

1 files changed, 62 insertions, 0 deletions

diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
index 94ae1792f77..a01f326e8d3 100644
--- a/gdb/gdbtypes.c
+++ b/gdb/gdbtypes.c
@@ -1955,6 +1955,68 @@ is_integral_type (struct type *t)
 	 || (TYPE_CODE (t) == TYPE_CODE_BOOL)));
 }
 
+/* Return true if TYPE is scalar.  */
+
+static int
+is_scalar_type (struct type *type)
+{
+  CHECK_TYPEDEF (type);
+
+  switch (TYPE_CODE (type))
+    {
+    case TYPE_CODE_ARRAY:
+    case TYPE_CODE_STRUCT:
+    case TYPE_CODE_UNION:
+    case TYPE_CODE_SET:
+    case TYPE_CODE_STRING:
+    case TYPE_CODE_BITSTRING:
+      return 0;
+    default:
+      return 1;
+    }
+}
+
+/* Return true if T is scalar, or a composite type which in practice has
+   the memory layout of a scalar type. E.g., an array or struct with only one
+   scalar element inside it, or a union with only scalar elements.  */
+
+int
+is_scalar_type_recursive (struct type *t)
+{
+  CHECK_TYPEDEF (t);
+
+  if (is_scalar_type (t))
+    return 1;
+  /* Are we dealing with an array or string of known dimensions?  */
+  else if ((TYPE_CODE (t) == TYPE_CODE_ARRAY
+	    || TYPE_CODE (t) == TYPE_CODE_STRING) && TYPE_NFIELDS (t) == 1
+	   && TYPE_CODE (TYPE_INDEX_TYPE (t)) == TYPE_CODE_RANGE)
+    {
+      LONGEST low_bound, high_bound;
+      struct type *elt_type = check_typedef (TYPE_TARGET_TYPE (t));
+
+      get_discrete_bounds (TYPE_INDEX_TYPE (t), &low_bound, &high_bound);
+
+      return high_bound == low_bound && is_scalar_type_recursive (elt_type);
+    }
+  /* Are we dealing with a struct with one element?  */
+  else if (TYPE_CODE (t) == TYPE_CODE_STRUCT && TYPE_NFIELDS (t) == 1)
+    return is_scalar_type_recursive (TYPE_FIELD_TYPE (t, 0));
+  else if (TYPE_CODE (t) == TYPE_CODE_UNION)
+    {
+      int i, n = TYPE_NFIELDS (t);
+
+      /* If all elements of the union are scalar, then the union is scalar.  */
+      for (i = 0; i < n; i++)
+	if (!is_scalar_type_recursive (TYPE_FIELD_TYPE (t, i)))
+	  return 0;
+
+      return 1;
+    }
+
+  return 0;
+}
+
 /* A helper function which returns true if types A and B represent the
    "same" class type.  This is true if the types have the same main
    type, or the same name.  */