+/* Subroutine of detect_field_duplicates: return whether X and Y,
+ which are both fields in the same struct, have duplicate field
+ names. */
+
+static bool
+is_duplicate_field (tree x, tree y)
+{
+ if (DECL_NAME (x) != NULL_TREE && DECL_NAME (x) == DECL_NAME (y))
+ return true;
+
+ /* When using -fplan9-extensions, an anonymous field whose name is a
+ typedef can duplicate a field name. */
+ if (flag_plan9_extensions
+ && (DECL_NAME (x) == NULL_TREE || DECL_NAME (y) == NULL_TREE))
+ {
+ tree xt, xn, yt, yn;
+
+ xt = TREE_TYPE (x);
+ if (DECL_NAME (x) != NULL_TREE)
+ xn = DECL_NAME (x);
+ else if ((TREE_CODE (xt) == RECORD_TYPE || TREE_CODE (xt) == UNION_TYPE)
+ && TYPE_NAME (xt) != NULL_TREE
+ && TREE_CODE (TYPE_NAME (xt)) == TYPE_DECL)
+ xn = DECL_NAME (TYPE_NAME (xt));
+ else
+ xn = NULL_TREE;
+
+ yt = TREE_TYPE (y);
+ if (DECL_NAME (y) != NULL_TREE)
+ yn = DECL_NAME (y);
+ else if ((TREE_CODE (yt) == RECORD_TYPE || TREE_CODE (yt) == UNION_TYPE)
+ && TYPE_NAME (yt) != NULL_TREE
+ && TREE_CODE (TYPE_NAME (yt)) == TYPE_DECL)
+ yn = DECL_NAME (TYPE_NAME (yt));
+ else
+ yn = NULL_TREE;
+
+ if (xn != NULL_TREE && xn == yn)
+ return true;
+ }
+
+ return false;
+}
+
+/* Subroutine of detect_field_duplicates: add the fields of FIELDLIST
+ to HTAB, giving errors for any duplicates. */
+
+static void
+detect_field_duplicates_hash (tree fieldlist, htab_t htab)
+{
+ tree x, y;
+ void **slot;
+
+ for (x = fieldlist; x ; x = DECL_CHAIN (x))
+ if ((y = DECL_NAME (x)) != 0)
+ {
+ slot = htab_find_slot (htab, y, INSERT);
+ if (*slot)
+ {
+ error ("duplicate member %q+D", x);
+ DECL_NAME (x) = NULL_TREE;
+ }
+ *slot = y;
+ }
+ else if (TREE_CODE (TREE_TYPE (x)) == RECORD_TYPE
+ || TREE_CODE (TREE_TYPE (x)) == UNION_TYPE)
+ {
+ detect_field_duplicates_hash (TYPE_FIELDS (TREE_TYPE (x)), htab);
+
+ /* When using -fplan9-extensions, an anonymous field whose
+ name is a typedef can duplicate a field name. */
+ if (flag_plan9_extensions
+ && TYPE_NAME (TREE_TYPE (x)) != NULL_TREE
+ && TREE_CODE (TYPE_NAME (TREE_TYPE (x))) == TYPE_DECL)
+ {
+ tree xn = DECL_NAME (TYPE_NAME (TREE_TYPE (x)));
+ slot = htab_find_slot (htab, xn, INSERT);
+ if (*slot)
+ error ("duplicate member %q+D", TYPE_NAME (TREE_TYPE (x)));
+ *slot = xn;
+ }
+ }
+}
+