+
+#include "pmap.h"
+
+#include "irnode_t.h"
+#include "irhooks.h"
+#include "irgwalk.h"
+
+#include "survive_dce.h"
+
+struct _survive_dce_t {
+ pmap *places;
+ pmap *new_places;
+ hook_entry_t dead_node_elim;
+ hook_entry_t dead_node_elim_subst;
+};
+
+static void dead_node_hook(void *context, ir_graph *irg, int start)
+{
+ survive_dce_t *sd = context;
+
+ /* Create a new map before the dead node elimination is performed. */
+ if(start) {
+ sd->new_places = pmap_create_ex(pmap_count(sd->places));
+ }
+
+ /* Patch back all nodes if dead node elimination is over and something is to be done. */
+ else {
+ pmap_destroy(sd->places);
+ sd->places = sd->new_places;
+ sd->new_places = NULL;
+ }
+}
+
+static void dead_node_subst_hook(void *context, ir_graph *irg, ir_node *old, ir_node *nw)
+{
+ survive_dce_t *sd = context;
+ ir_node **place = (ir_node **) pmap_get(sd->places, old);
+
+ /* If the node is to be patched back, do it. */
+ if(place) {
+ *place = nw;
+ pmap_insert(sd->new_places, nw, (void *) place);
+ }
+}
+
+survive_dce_t *new_survive_dce(void)
+{
+ survive_dce_t *res = xmalloc(sizeof(res[0]));
+ res->places = pmap_create();
+ res->new_places = NULL;
+
+ res->dead_node_elim.hook._hook_dead_node_elim = dead_node_hook;
+ res->dead_node_elim.context = res;
+ res->dead_node_elim.next = NULL;
+
+ res->dead_node_elim_subst.hook._hook_dead_node_elim_subst = dead_node_subst_hook;
+ res->dead_node_elim_subst.context = res;
+ res->dead_node_elim_subst.next = NULL;
+
+ register_hook(hook_dead_node_elim, &res->dead_node_elim);
+ register_hook(hook_dead_node_elim_subst, &res->dead_node_elim_subst);
+ return res;
+}
+
+void free_survive_dce(survive_dce_t *sd)
+{
+ pmap_destroy(sd->places);
+ unregister_hook(hook_dead_node_elim, &sd->dead_node_elim);
+ unregister_hook(hook_dead_node_elim_subst, &sd->dead_node_elim_subst);
+ free(sd);
+}
+
+void survive_dce_register_irn(survive_dce_t *sd, ir_node **place)
+{
+ pmap_insert(sd->places, *place, (void *) place);
+}