+/**
+ * Pre-Walker: Copies blocks and nodes from the original method graph
+ * to the copied graph.
+ *
+ * @param n A node from the original method graph.
+ * @param env The copied graph.
+ */
+static void copy_all_nodes(ir_node *n, void *env) {
+ ir_graph *irg = env;
+ ir_op *op = get_irn_op(n);
+ ir_node *nn;
+
+ nn = new_ir_node(get_irn_dbg_info(n),
+ irg,
+ NULL, /* no block yet, will be set later */
+ op,
+ get_irn_mode(n),
+ get_irn_arity(n),
+ get_irn_in(n) + 1);
+
+
+ /* Copy the attributes. These might point to additional data. If this
+ was allocated on the old obstack the pointers now are dangling. This
+ frees e.g. the memory of the graph_arr allocated in new_immBlock. */
+ copy_node_attr(n, nn);
+ new_backedge_info(nn);
+ set_irn_link(n, nn);
+
+ /* fix the irg for blocks */
+ if (is_Block(nn))
+ nn->attr.block.irg = irg;
+
+ /* fix access to entities on the stack frame */
+ if (is_Sel(nn)) {
+ ir_entity *ent = get_Sel_entity(nn);
+ ir_type *tp = get_entity_owner(ent);
+
+ if (is_frame_type(tp)) {
+ /* replace by the copied entity */
+ ent = get_entity_link(ent);
+
+ assert(is_entity(ent));
+ assert(get_entity_owner(ent) == get_irg_frame_type(irg));
+ set_Sel_entity(nn, ent);
+ }
+ }
+}
+
+/**
+ * Post-walker: Set the predecessors of the copied nodes.
+ * The copied nodes are set as link of their original nodes. The links of
+ * "irn" predecessors are the predecessors of copied node.
+ */
+static void set_all_preds(ir_node *irn, void *env) {
+ int i;
+ ir_node *nn, *pred;
+ (void) env;
+
+ nn = get_irn_link(irn);
+
+ if (is_Block(irn)) {
+ ir_node *mbh = get_Block_MacroBlock(irn);
+ set_Block_MacroBlock(nn, get_irn_link(mbh));
+ for (i = get_Block_n_cfgpreds(irn) - 1; i >= 0; i--) {
+ pred = get_Block_cfgpred(irn, i);
+ set_Block_cfgpred(nn, i, get_irn_link(pred));
+ }
+ } else {
+ /* First we set the block our copy if it is not a block.*/
+ set_nodes_block(nn, get_irn_link(get_nodes_block(irn)));
+ for (i = get_irn_arity(irn) - 1; i >= 0; i--) {
+ pred = get_irn_n(irn, i);
+ set_irn_n(nn, i, get_irn_link(pred));
+ }
+ }
+}
+
+#define NN(irn) get_irn_link(irn)
+
+/*
+ * Create a new graph that is a copy of a given one.
+ */
+ir_graph *create_irg_copy(ir_graph *irg) {
+ ir_graph *res;
+
+ res = alloc_graph();
+
+ res->n_loc = 0;
+ res->visited = 0; /* visited flag, for the ir walker */
+ res->block_visited = 0; /* visited flag, for the 'block'-walker */
+#if USE_EXPLICIT_PHI_IN_STACK
+ res->Phi_in_stack = NULL;
+#endif
+ res->obst = xmalloc(sizeof(*res->obst));
+ obstack_init(res->obst);
+ res->extbb_obst = NULL;
+
+ res->last_node_idx = 0;
+
+ res->phase_state = irg->phase_state;
+ res->irg_pinned_state = irg->irg_pinned_state;
+ res->extblk_state = ir_extblk_info_none;
+ res->fp_model = irg->fp_model;
+
+ res->value_table = new_identities();
+
+ /* clone the frame type here for safety */
+ res->frame_type = clone_frame_type(irg->frame_type);
+
+ res->phase_state = irg->phase_state;
+
+ ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
+
+ /* copy all nodes from the graph irg to the new graph res */
+ irg_walk_anchors(irg, copy_all_nodes, set_all_preds, res);
+
+ /* copy the Anchor node */
+ res->anchor = NN(irg->anchor);
+
+ /* -- The end block -- */
+ set_irg_end_block (res, NN(get_irg_end_block(irg)));
+ set_irg_end (res, NN(get_irg_end(irg)));
+ set_irg_end_reg (res, NN(get_irg_end_reg(irg)));
+ set_irg_end_except(res, NN(get_irg_end_except(irg)));
+
+ /* -- The start block -- */
+ set_irg_start_block(res, NN(get_irg_start_block(irg)));
+ set_irg_bad (res, NN(get_irg_bad(irg)));
+ set_irg_no_mem (res, NN(get_irg_no_mem(irg)));
+ set_irg_start (res, NN(get_irg_start(irg)));
+
+ /* Proj results of start node */
+ set_irg_initial_mem(res, NN(get_irg_initial_mem(irg)));
+
+ /* Copy the node count estimation. Would be strange if this
+ is different from the original one. */
+ res->estimated_node_count = irg->estimated_node_count;
+
+ ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
+
+ return res;
+}
+#undef NN
+