+/* Assuming that INDEX_DESC_TYPE is an ___XA structure, a structure
+ generated by the GNAT compiler to describe the index type used
+ for each dimension of an array, check whether it follows the latest
+ known encoding. If not, fix it up to conform to the latest encoding.
+ Otherwise, do nothing. This function also does nothing if
+ INDEX_DESC_TYPE is NULL.
+
+ The GNAT encoding used to describle the array index type evolved a bit.
+ Initially, the information would be provided through the name of each
+ field of the structure type only, while the type of these fields was
+ described as unspecified and irrelevant. The debugger was then expected
+ to perform a global type lookup using the name of that field in order
+ to get access to the full index type description. Because these global
+ lookups can be very expensive, the encoding was later enhanced to make
+ the global lookup unnecessary by defining the field type as being
+ the full index type description.
+
+ The purpose of this routine is to allow us to support older versions
+ of the compiler by detecting the use of the older encoding, and by
+ fixing up the INDEX_DESC_TYPE to follow the new one (at this point,
+ we essentially replace each field's meaningless type by the associated
+ index subtype). */
+
+void
+ada_fixup_array_indexes_type (struct type *index_desc_type)
+{
+ int i;
+
+ if (index_desc_type == NULL)
+ return;
+ gdb_assert (TYPE_NFIELDS (index_desc_type) > 0);
+
+ /* Check if INDEX_DESC_TYPE follows the older encoding (it is sufficient
+ to check one field only, no need to check them all). If not, return
+ now.
+
+ If our INDEX_DESC_TYPE was generated using the older encoding,
+ the field type should be a meaningless integer type whose name
+ is not equal to the field name. */
+ if (TYPE_NAME (TYPE_FIELD_TYPE (index_desc_type, 0)) != NULL
+ && strcmp (TYPE_NAME (TYPE_FIELD_TYPE (index_desc_type, 0)),
+ TYPE_FIELD_NAME (index_desc_type, 0)) == 0)
+ return;
+
+ /* Fixup each field of INDEX_DESC_TYPE. */
+ for (i = 0; i < TYPE_NFIELDS (index_desc_type); i++)
+ {
+ char *name = TYPE_FIELD_NAME (index_desc_type, i);
+ struct type *raw_type = ada_check_typedef (ada_find_any_type (name));
+
+ if (raw_type)
+ TYPE_FIELD_TYPE (index_desc_type, i) = raw_type;
+ }
+}
+