+extern int arch_get_allocatable_regs(const arch_env_t *env, const ir_node *irn,
+ int pos, const arch_register_class_t *cls, bitset_t *bs);
+
+/**
+ * Check, if a register is assignable to an operand of a node.
+ * @param env The architecture environment.
+ * @param irn The node.
+ * @param pos The position of the operand.
+ * @param reg The register.
+ * @return 1, if the register might be allocated to the operand 0 if not.
+ */
+extern int arch_reg_is_allocatable(const arch_env_t *env,
+ const ir_node *irn, int pos, const arch_register_t *reg);
+
+/**
+ * Get the register class of an operand of a node.
+ * @param env The architecture environment.
+ * @param irn The node.
+ * @param pos The position of the operand.
+ * @return The register class of the operand or NULL, if
+ * operand is a non-register operand.
+ */
+extern const arch_register_class_t *
+arch_get_irn_reg_class(const arch_env_t *env, const ir_node *irn, int pos);
+
+/**
+ * Get the register allocated at a certain output operand of a node.
+ * @param env The arch environment.
+ * @param irn The node.
+ * @return The register allocated for this operand
+ */
+extern const arch_register_t *
+arch_get_irn_register(const arch_env_t *env, const ir_node *irn);
+
+/**
+ * Set the register for a certain output operand.
+ * @param env The architecture environment.
+ * @param irn The node.
+ * @param idx The index of the output operand.
+ * @param reg The register.
+ */
+extern void arch_set_irn_register(const arch_env_t *env, ir_node *irn,
+ const arch_register_t *reg);
+
+/**
+ * Classify a node.
+ * @param env The architecture environment.
+ * @param irn The node.
+ * @return A classification of the node.
+ */
+extern arch_irn_class_t arch_irn_classify(const arch_env_t *env, const ir_node *irn);
+
+/**
+ * Get the flags of a node.
+ * @param env The architecture environment.
+ * @param irn The node.
+ * @return The flags.
+ */
+extern arch_irn_flags_t arch_irn_get_flags(const arch_env_t *env, const ir_node *irn);
+
+#define arch_irn_has_reg_class(env, irn, pos, cls) \
+ ((cls) == arch_get_irn_reg_class(env, irn, pos))
+
+/**
+ * Somebody who can be asked about nodes.
+ */
+struct _arch_irn_handler_t {
+
+ /**
+ * Get the operations of an irn.
+ * @param self The handler from which the method is invoked.
+ * @param irn Some node.
+ * @return Operations for that irn.
+ */
+ const arch_irn_ops_t *(*get_irn_ops)(const arch_irn_handler_t *handler,
+ const ir_node *irn);
+