Constified a little bit.

[r4539]

ir/ir/irnode.c

@@ -238,19 +238,19 @@ set_irn_in (ir_node *node, int arity, ir_node **in) {
 }
 
 ir_node *
-(get_irn_intra_n)(ir_node *node, int n) {
+(get_irn_intra_n)(const ir_node *node, int n) {
   return __get_irn_intra_n (node, n);
 }
 
 ir_node *
-(get_irn_inter_n)(ir_node *node, int n) {
+(get_irn_inter_n)(const ir_node *node, int n) {
   return __get_irn_inter_n (node, n);
 }
 
-ir_node *(*__get_irn_n)(ir_node *node, int n) = __get_irn_intra_n;
+ir_node *(*__get_irn_n)(const ir_node *node, int n) = __get_irn_intra_n;
 
 ir_node *
-(get_irn_n)(ir_node *node, int n) {
+(get_irn_n)(const ir_node *node, int n) {
   return __get_irn_n(node, n);
 }
 
@@ -527,7 +527,7 @@ get_irn_except_attr (ir_node *node)
 
 /* this works for all except Block */
 ir_node *
-get_nodes_block (ir_node *node) {
+get_nodes_block (const ir_node *node) {
   assert (!(node->op == op_Block));
   return get_irn_n(node, -1);
 }

ir/ir/irnode.h

@@ -133,9 +133,9 @@ void          set_irn_in            (ir_node *node, int arity,
  * Get the n-th predecessor of a node.
  * This function removes Id predecessors.
  */
-ir_node      *get_irn_n             (ir_node *node, int n);
-ir_node      *get_irn_intra_n       (ir_node *node, int n);
-ir_node      *get_irn_inter_n       (ir_node *node, int n);
+ir_node      *get_irn_n             (const ir_node *node, int n);
+ir_node      *get_irn_intra_n       (const ir_node *node, int n);
+ir_node      *get_irn_inter_n       (const ir_node *node, int n);
 
 /** Replace the n-th predecessor of a node with a new one. */
 void          set_irn_n             (ir_node *node, int n, ir_node *in);
@@ -223,7 +223,7 @@ new_ir_node (dbg_info *db,
  * To express the difference to access routines that work for all
  * nodes we use infix "nodes" and do not name this function
  * get_irn_block. */
-ir_node  *get_nodes_block (ir_node *node);
+ir_node  *get_nodes_block (const ir_node *node);
 
 /** Sets the Block of a node. */
 void      set_nodes_block (ir_node *node, ir_node *block);
@@ -904,7 +904,16 @@ int is_forking_op(const ir_node *node);
  * @return A pointer of type @p type.
  */
 #define get_irn_data(node,type,off) \
- (assert(off > 0 && "Invalid node data offset"), (type *) ((char *) (node) - (off)))
+  (assert(off > 0 && "Invalid node data offset"), (type *) ((char *) (node) - (off)))
+
+/**
+ * Get the pointer to the node some custom data belongs to.
+ * @param data The pointer to the custom data.
+ * @param off The number as returned by register_additional_node_data().
+ * @return A pointer to the ir node the custom data belongs to.
+ */
+#define get_irn_data_base(data,off) \
+  (assert(off > 0 && "Invalid node data offset"), (ir_node *) ((char *) (data) + (off)))
 
 /**
  * Request additional data to be allocated with an ir node.

ir/ir/irnode_t.h

@@ -41,6 +41,7 @@
 #include "entity_t.h"
 #include "type_t.h"
 
+
 /** ir node attributes **/
 
 /** Block attributes */
@@ -339,7 +340,7 @@ extern int (*__get_irn_arity)(const ir_node *node);
  * Intern version for libFirm.
  */
 static INLINE ir_node *
-__get_irn_intra_n (ir_node *node, int n) {
+__get_irn_intra_n (const ir_node *node, int n) {
   assert(node); assert(-1 <= n && n < __get_irn_intra_arity(node));
 
   return (node->in[n + 1] = skip_Id(node->in[n + 1]));
@@ -349,7 +350,7 @@ __get_irn_intra_n (ir_node *node, int n) {
  * Intern version for libFirm.
  */
 static INLINE ir_node*
-__get_irn_inter_n (ir_node *node, int n) {
+__get_irn_inter_n (const ir_node *node, int n) {
   assert(node); assert(-1 <= n && n < __get_irn_inter_arity(node));
 
   /* handle Filter and Block specially */
@@ -371,7 +372,7 @@ __get_irn_inter_n (ir_node *node, int n) {
  * If it is a block, the entry -1 is NULL.
  * Intern version for libFirm.
  */
-extern ir_node *(*__get_irn_n)(ir_node *node, int n);
+extern ir_node *(*__get_irn_n)(const ir_node *node, int n);
 
 /**
  * Gets the mode of a node.