Moved survive dce stuff here.

[r7447]

diff --git a/ir/ir/irgopt.c b/ir/ir/irgopt.c
index 14867bb..3592807 100644 (file)
--- a/ir/ir/irgopt.c
+++ b/ir/ir/irgopt.c
@@ -29,6 +29,7 @@
 
 #include "array.h"
 #include "pset.h"
+#include "pmap.h"
 #include "eset.h"
 #include "pdeq.h"       /* Fuer code placement */
 #include "xmalloc.h"
@@ -665,6 +666,118 @@ void remove_bad_predecessors(ir_graph *irg) {
 }
 
 
+/*
+        __                      _  __ __
+       (_     __    o     _    | \/  |_
+       __)|_| | \_/ | \_/(/_   |_/\__|__
+
+  The following stuff implements a facility that automatically patches
+  registered ir_node pointers to the new node when a dead node elimination occurs.
+*/
+
+struct _survive_dce_t {
+       struct obstack obst;
+       pmap *places;
+       pmap *new_places;
+       hook_entry_t dead_node_elim;
+       hook_entry_t dead_node_elim_subst;
+};
+
+typedef struct _survive_dce_list_t {
+       struct _survive_dce_list_t *next;
+       ir_node **place;
+} survive_dce_list_t;
+
+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;
+       survive_dce_list_t *list = pmap_get(sd->places, old);
+
+       /* If the node is to be patched back, write the new address to all registered locations. */
+       if(list) {
+               survive_dce_list_t *p;
+
+               for(p = list; p; p = p->next)
+                       *(p->place) = nw;
+
+               pmap_insert(sd->new_places, nw, list);
+       }
+}
+
+/**
+ * Make a new Survive DCE environment.
+ */
+survive_dce_t *new_survive_dce(void)
+{
+       survive_dce_t *res = xmalloc(sizeof(res[0]));
+       obstack_init(&res->obst);
+       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;
+}
+
+/**
+ * Free a Survive DCE environment.
+ */
+void free_survive_dce(survive_dce_t *sd)
+{
+       obstack_free(&sd->obst, NULL);
+       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);
+}
+
+/**
+ * Register a node pointer to be patched upon DCE.
+ * When DCE occurs, the node pointer specified by @p place will be
+ * patched to the new address of the node it is pointing to.
+ *
+ * @param sd    The Survive DCE environment.
+ * @param place The address of the node pointer.
+ */
+void survive_dce_register_irn(survive_dce_t *sd, ir_node **place)
+{
+       if(*place != NULL) {
+               ir_node *irn      = *place;
+               survive_dce_list_t *curr = pmap_get(sd->places, irn);
+               survive_dce_list_t *nw   = obstack_alloc(&sd->obst, sizeof(nw));
+
+               nw->next  = curr;
+               nw->place = place;
+
+               pmap_insert(sd->places, irn, nw);
+       }
+}
+
 /*--------------------------------------------------------------------*/
 /*  Functionality for inlining                                         */
 /*--------------------------------------------------------------------*/

diff --git a/ir/ir/irgopt.h b/ir/ir/irgopt.h
index 5dab689..789186c 100644 (file)
--- a/ir/ir/irgopt.h
+++ b/ir/ir/irgopt.h
@@ -58,6 +58,28 @@ void local_optimize_graph (ir_graph *irg);
  */
 void dead_node_elimination(ir_graph *irg);
 
+typedef struct _survive_dce_t survive_dce_t;
+
+/**
+ * Make a new Survive DCE environment.
+ */
+survive_dce_t *new_survive_dce(void);
+
+/**
+ * Free a Survive DCE environment.
+ */
+void free_survive_dce(survive_dce_t *sd);
+
+/**
+ * Register a node pointer to be patched upon DCE.
+ * When DCE occurs, the node pointer specified by @p place will be
+ * patched to the new address of the node it is pointing to.
+ *
+ * @param sd    The Survive DCE environment.
+ * @param place The address of the node pointer.
+ */
+void survive_dce_register_irn(survive_dce_t *sd, ir_node **place);
+
 /**  Cleans the control flow from Bad predecesors.
  *
  * Removes Bad predecesors from Blocks and the corresponding