gdb/ChangeLog:

Add support for DW_AT_GNAT_descriptive_type.
        * gdbtypes.h (enum type_specific_kind): New enum.
        (struct main_type) [type_specific_field]: New component.
        [type_specific]: Add new component "gnat_stuff".
        (struct gnat_aux_type): New type.
        (INIT_CPLUS_SPECIFIC): Also set TYPE_SPECIFIC_FIELD (type).
        (HAVE_CPLUS_STRUCT): Also check TYPE_SPECIFIC_FIELD (type).
        (gnat_aux_default, allocate_gnat_aux_type): Add declaration.
        (INIT_GNAT_SPECIFIC, ALLOCATE_GNAT_AUX_TYPE, HAVE_GNAT_AUX_INFO)
        (TYPE_SPECIFIC_FIELD): New macros.
        (TYPE_CPLUS_SPECIFIC): Return cplus_struct_default if the given
        type does not hold any cplus-specific data.
        (TYPE_RAW_CPLUS_SPECIFIC): New macro.
        (TYPE_GNAT_SPECIFIC, TYPE_DESCRIPTIVE_TYPE): New macros.
        (TYPE_IS_OPAQUE): Use HAVE_CPLUS_STRUCT to check if type has
        cplus-specific data.
        * gdbtypes.c (allocate_cplus_struct_type): Minor stylistic rewrite.
        Set new component TYPE_SPECIFIC_FIELD (type).
        (gnat_aux_default): New constant.
        (allocate_gnat_aux_type): New function.
        (init_type): Add initialization the type-specific stuff for
        TYPE_CODE_FLT and TYPE_CODE_FUNC types.
        (print_gnat_stuff): New function.
        (recursive_dump_type): Use HAVE_CPLUS_STRUCT to check for cplus-
        specific data.  Adjust code that prints the contents of the
        type-specific union using the TYPE_SPECIFIC_FIELD value.
        * dwarf2read.c (dwarf2_attach_fields_to_type): Do not allocate
        the type cplus stuff for Ada types.
        (dwarf2_add_member_fn, dwarf2_attach_fn_fields_to_type):
        Error out if these routines are called with an Ada type.
        (read_structure_type, read_array_type, read_subrange_type):
        Add call to set_descriptive_type.
        (set_die_type): Initialize the gnat-specific data if necessary.
        (need_gnat_info, die_descriptive_type, set_descriptive_type):
        New functions.
        * ada-lang.c (decode_constrained_packed_array_type): Use
        decode_constrained_packed_array_type instead of doing a standard
        lookup to locate a parallel type.
        (find_parallel_type_by_descriptive_type): New function.
        (ada_find_parallel_type_with_name): New function.
        (ada_find_parallel_type): Reimplement using
        ada_find_parallel_type_with_name.
        * ada-valprint.c (print_field_values): Use HAVE_CPLUS_STRUCT
        to check if type has a cplus stuff.
        * linespec.c (total_number_of_methods): Likewise.
        * mdebugread.c (new_type): Likewise.

gdb/testsuite/ChangeLog:

        * gdb.base/maint.exp: Adjust the expected output for the
        "maint print type" test. Use gdb_test_multiple instead of
        gdb_sent/gdb_expect.

gdb/dwarf2read.c

@@ -926,6 +926,13 @@ static void dwarf2_const_value_data (struct attribute *attr,
 
 static struct type *die_type (struct die_info *, struct dwarf2_cu *);
 
+static int need_gnat_info (struct dwarf2_cu *);
+
+static struct type *die_descriptive_type (struct die_info *, struct dwarf2_cu *);
+
+static void set_descriptive_type (struct type *, struct die_info *,
+				  struct dwarf2_cu *);
+
 static struct type *die_containing_type (struct die_info *,
 					 struct dwarf2_cu *);
 
@@ -4564,7 +4571,7 @@ dwarf2_attach_fields_to_type (struct field_info *fip, struct type *type,
     TYPE_ALLOC (type, sizeof (struct field) * nfields);
   memset (TYPE_FIELDS (type), 0, sizeof (struct field) * nfields);
 
-  if (fip->non_public_fields)
+  if (fip->non_public_fields && cu->language != language_ada)
     {
       ALLOCATE_CPLUS_STRUCT_TYPE (type);
 
@@ -4583,7 +4590,7 @@ dwarf2_attach_fields_to_type (struct field_info *fip, struct type *type,
 
   /* If the type has baseclasses, allocate and clear a bit vector for
      TYPE_FIELD_VIRTUAL_BITS.  */
-  if (fip->nbaseclasses)
+  if (fip->nbaseclasses && cu->language != language_ada)
     {
       int num_bytes = B_BYTES (fip->nbaseclasses);
       unsigned char *pointer;
@@ -4617,11 +4624,13 @@ dwarf2_attach_fields_to_type (struct field_info *fip, struct type *type,
       switch (fieldp->accessibility)
 	{
 	case DW_ACCESS_private:
-	  SET_TYPE_FIELD_PRIVATE (type, nfields);
+	  if (cu->language != language_ada)
+	    SET_TYPE_FIELD_PRIVATE (type, nfields);
 	  break;
 
 	case DW_ACCESS_protected:
-	  SET_TYPE_FIELD_PROTECTED (type, nfields);
+	  if (cu->language != language_ada)
+	    SET_TYPE_FIELD_PROTECTED (type, nfields);
 	  break;
 
 	case DW_ACCESS_public:
@@ -4641,6 +4650,8 @@ dwarf2_attach_fields_to_type (struct field_info *fip, struct type *type,
 	    {
 	    case DW_VIRTUALITY_virtual:
 	    case DW_VIRTUALITY_pure_virtual:
+	      if (cu->language == language_ada)
+		error ("unexpected virtuality in component of Ada type");
 	      SET_TYPE_FIELD_VIRTUAL (type, nfields);
 	      break;
 	    }
@@ -4664,6 +4675,9 @@ dwarf2_add_member_fn (struct field_info *fip, struct die_info *die,
   struct nextfnfield *new_fnfield;
   struct type *this_type;
 
+  if (cu->language == language_ada)
+    error ("unexpected member function in Ada type");
+
   /* Get name of member function.  */
   fieldname = dwarf2_name (die, cu);
   if (fieldname == NULL)
@@ -4837,6 +4851,9 @@ dwarf2_attach_fn_fields_to_type (struct field_info *fip, struct type *type,
   int total_length = 0;
   int i;
 
+  if (cu->language == language_ada)
+    error ("unexpected member functions in Ada type");
+
   ALLOCATE_CPLUS_STRUCT_TYPE (type);
   TYPE_FN_FIELDLISTS (type) = (struct fn_fieldlist *)
     TYPE_ALLOC (type, sizeof (struct fn_fieldlist) * fip->nfnfields);
@@ -5038,6 +5055,8 @@ read_structure_type (struct die_info *die, struct dwarf2_cu *cu)
   if (die_is_declaration (die, cu))
     TYPE_STUB (type) = 1;
 
+  set_descriptive_type (type, die, cu);
+
   /* We need to add the type field to the die immediately so we don't
      infinitely recurse when dealing with pointers to the structure
      type within the structure itself. */
@@ -5451,6 +5470,8 @@ read_array_type (struct die_info *die, struct dwarf2_cu *cu)
   if (name)
     TYPE_NAME (type) = name;
   
+  set_descriptive_type (type, die, cu);
+
   do_cleanups (back_to);
 
   /* Install the type in the die. */
@@ -6113,6 +6134,8 @@ read_subrange_type (struct die_info *die, struct dwarf2_cu *cu)
   if (attr)
     TYPE_LENGTH (range_type) = DW_UNSND (attr);
 
+  set_descriptive_type (range_type, die, cu);
+
   return set_die_type (die, range_type, cu);
 }
   
@@ -8768,6 +8791,67 @@ die_type (struct die_info *die, struct dwarf2_cu *cu)
   return type;
 }
 
+/* True iff CU's producer generates GNAT Ada auxiliary information
+   that allows to find parallel types through that information instead
+   of having to do expensive parallel lookups by type name.  */
+
+static int
+need_gnat_info (struct dwarf2_cu *cu)
+{
+  /* FIXME: brobecker/2010-10-12: As of now, only the AdaCore version
+     of GNAT produces this auxiliary information, without any indication
+     that it is produced.  Part of enhancing the FSF version of GNAT
+     to produce that information will be to put in place an indicator
+     that we can use in order to determine whether the descriptive type
+     info is available or not.  One suggestion that has been made is
+     to use a new attribute, attached to the CU die.  For now, assume
+     that the descriptive type info is not available.  */
+  return 0;
+}
+
+
+/* Return the auxiliary type of the die in question using its
+   DW_AT_GNAT_descriptive_type attribute.  Returns NULL if the
+   attribute is not present.  */
+
+static struct type *
+die_descriptive_type (struct die_info *die, struct dwarf2_cu *cu)
+{
+  struct type *type;
+  struct attribute *type_attr;
+  struct die_info *type_die;
+
+  type_attr = dwarf2_attr (die, DW_AT_GNAT_descriptive_type, cu);
+  if (!type_attr)
+    return NULL;
+
+  type_die = follow_die_ref (die, type_attr, &cu);
+  type = tag_type_to_type (type_die, cu);
+  if (!type)
+    {
+      dump_die_for_error (type_die);
+      error (_("Dwarf Error: Problem turning type die at offset into gdb type [in module %s]"),
+		      cu->objfile->name);
+    }
+  return type;
+}
+
+/* If DIE has a descriptive_type attribute, then set the TYPE's
+   descriptive type accordingly.  */
+
+static void
+set_descriptive_type (struct type *type, struct die_info *die,
+		      struct dwarf2_cu *cu)
+{
+  struct type *descriptive_type = die_descriptive_type (die, cu);
+
+  if (descriptive_type)
+    {
+      ALLOCATE_GNAT_AUX_TYPE (type);
+      TYPE_DESCRIPTIVE_TYPE (type) = descriptive_type;
+    }
+}
+
 /* Return the containing type of the die in question using its
    DW_AT_containing_type attribute.  */
 
@@ -11724,6 +11808,19 @@ set_die_type (struct die_info *die, struct type *type, struct dwarf2_cu *cu)
 {
   struct dwarf2_offset_and_type **slot, ofs;
 
+  /* For Ada types, make sure that the gnat-specific data is always
+     initialized (if not already set).  There are a few types where
+     we should not be doing so, because the type-specific area is
+     already used to hold some other piece of info (eg: TYPE_CODE_FLT
+     where the type-specific area is used to store the floatformat).
+     But this is not a problem, because the gnat-specific information
+     is actually not needed for these types.  */
+  if (need_gnat_info (cu)
+      && TYPE_CODE (type) != TYPE_CODE_FUNC
+      && TYPE_CODE (type) != TYPE_CODE_FLT
+      && !HAVE_GNAT_AUX_INFO (type))
+    INIT_GNAT_SPECIFIC (type);
+
   if (cu->type_hash == NULL)
     {
       gdb_assert (cu->per_cu != NULL);