+ /**
+ * Called before scheduling starts on a block.
+ * May be NULL.
+ *
+ * @param graph_env The environment.
+ * @param block The block which is to be scheduled.
+ * @return A per-block pointer that is additionally passed to select.
+ */
+ void *(*init_block)(void *graph_env, ir_node *block);
+
+ /**
+ * The selection function.
+ * It picks one node out of the ready list to be scheduled next.
+ * The function does not have to delete the node from the ready set.
+ * MUST be implemented.
+ *
+ * @param block_env Some private information as returned by init_block().
+ * @param sched_head The schedule so far.
+ * @param ready_set A set containing all ready nodes. Pick one of these nodes.
+ * @return The chosen node.
+ */
+ ir_node *(*select)(void *block_env, ir_nodeset_t *ready_set);
+
+ /**
+ * This function gets executed after a node finally has been made ready.
+ * May be NULL.
+ *
+ * @param block_env The block environment.
+ * @param irn The node made ready.
+ * @param pred The previously scheduled node.
+ */
+ void (*node_ready)(void *block_env, ir_node *irn, ir_node *pred);
+
+ /**
+ * This function gets executed after a node finally has been selected.
+ * May be NULL.
+ *
+ * @param block_env The block environment.
+ * @param irn The selected node.
+ */
+ void (*node_selected)(void *block_env, ir_node *irn);
+
+ /**
+ * Called after a block has been scheduled.
+ * May be NULL.
+ *
+ * @param env The environment.
+ * @param block_env The per block environment as returned by init_block().
+ */
+ void (*finish_block)(void *block_env);
+
+ /**
+ * Called after a whole graph has been scheduled.
+ * May be NULL.
+ *
+ * @param env The environment.
+ */
+ void (*finish_graph)(void *env);
+} list_sched_selector_t;