+hook_constcharptr_const_tree_null (const_tree t ATTRIBUTE_UNUSED)
+{
+ return NULL;
+}
+
+tree
+hook_tree_tree_int_treep_bool_null (tree t0 ATTRIBUTE_UNUSED,
+ int i ATTRIBUTE_UNUSED,
+ tree *p ATTRIBUTE_UNUSED,
+ bool ignore ATTRIBUTE_UNUSED)
+{
+ return NULL;
+}
+
+tree
+hook_tree_tree_tree_null (tree t0 ATTRIBUTE_UNUSED, tree t1 ATTRIBUTE_UNUSED)
+{
+ return NULL;
+}
+
+tree
+hook_tree_tree_tree_tree_null (tree t0 ATTRIBUTE_UNUSED,
+ tree t1 ATTRIBUTE_UNUSED,
+ tree t2 ATTRIBUTE_UNUSED)
+{
+ return NULL;
+}
+
+/* Generic hook that takes a rtx and returns a NULL string. */
+const char *
+hook_constcharptr_const_rtx_null (const_rtx r ATTRIBUTE_UNUSED)
+{
+ return NULL;
+}
+
+const char *
+hook_constcharptr_const_tree_const_tree_null (const_tree t0 ATTRIBUTE_UNUSED,
+ const_tree t1 ATTRIBUTE_UNUSED)
+{
+ return NULL;
+}
+
+const char *
+hook_constcharptr_int_const_tree_null (int i ATTRIBUTE_UNUSED,
+ const_tree t0 ATTRIBUTE_UNUSED)
+{
+ return NULL;
+}
+
+const char *
+hook_constcharptr_int_const_tree_const_tree_null (int i ATTRIBUTE_UNUSED,
+ const_tree t0 ATTRIBUTE_UNUSED,
+ const_tree t1 ATTRIBUTE_UNUSED)
+{
+ return NULL;
+}
+
+/* Generic hook that takes a const_tree and returns NULL_TREE. */
+tree
+hook_tree_const_tree_null (const_tree t ATTRIBUTE_UNUSED)