-/** a pointer to the new phases */
-static ir_phase *new_phases[PHASE_LAST];
-
-/**
- * Copies the node to the new obstack. The Ins of the new node point to
- * the predecessors on the old obstack. For block/phi nodes not all
- * predecessors might be copied. n->link points to the new node.
- *
- * @param n The node to be copied
- * @param irg The irg onto which the node should be copied
- */
-static ir_node *copy_node(ir_node *n, ir_graph *irg)
-{
- ir_op *op = get_irn_op(n);
- int arity = get_irn_arity(n);
- dbg_info *dbgi = get_irn_dbg_info(n);
- ir_mode *mode = get_irn_mode(n);
- ir_node *nn;
- ir_node *block;
- int i;
-
- if (op == op_Block) {
- block = NULL;
- n->attr.block.graph_arr = NULL;
- } else {
- block = get_nodes_block(n);
- }
- if (op->opar == oparity_dynamic) {
- nn = new_ir_node(dbgi, irg, block, op, mode, -1, NULL);
- for (i = 0; i < arity; ++i) {
- ir_node *in = get_irn_n(n, i);
- add_irn_n(nn, in);
- }
- } else {
- ir_node **ins = get_irn_in(n)+1;
- nn = new_ir_node(dbgi, irg, block, op, mode, arity, ins);
- }
-
- /* Copy the attributes. These might point to additional data. If this
- was allocated on the old obstack the pointers now are dangling. */
- copy_node_attr(irg, n, nn);
- if (op == op_Block) {
- /* we cannot allow blocks WITHOUT macroblock input */
- set_Block_MacroBlock(nn, get_Block_MacroBlock(n));
- }
-
- /* copy phase information for this node */
- for (i = PHASE_NOT_IRG_MANAGED+1; i < PHASE_LAST; i++) {
- ir_graph *old_irg = get_irn_irg(n);
- ir_phase *old_ph = get_irg_phase(old_irg, i);
- if (old_ph == NULL)
- continue;
- if (!phase_get_irn_data(old_ph, n))
- continue;
- phase_set_irn_data(new_phases[i], nn, phase_get_irn_data(old_ph, n));
- }
-
- set_new_node(n, nn);
- hook_dead_node_elim_subst(current_ir_graph, n, nn);
-
- return nn;
-}
-
-static void copy_node_with_number(ir_node *node, void *env)
-{
- ir_graph *new_irg = (ir_graph*) env;
- ir_node *new_node = copy_node(node, new_irg);
-
- /* preserve the node numbers for easier debugging */
- new_node->node_nr = node->node_nr;
-}
-
-/**
- * Reroute the inputs of a node from nodes in the old graph to copied nodes in
- * the new graph
- */
-static void set_preds(ir_node *node, void *env)
-{
- ir_graph *new_irg = (ir_graph*) env;
- ir_node *new_node;
- int arity;
- int i;
-
- new_node = get_new_node(node);
-
- if (is_Block(node)) {
- /* copy the macro block header */
- ir_node *mbh = get_Block_MacroBlock(node);
-
- /* get the macro block header */
- ir_node *nmbh = get_new_node(mbh);
- assert(nmbh != NULL);
- set_Block_MacroBlock(new_node, nmbh);
- } else {
- ir_node *block = get_nodes_block(node);
- ir_node *new_block = get_new_node(block);
- set_nodes_block(new_node, new_block);
- }
-
- arity = get_irn_arity(new_node);
- for (i = 0; i < arity; ++i) {
- ir_node *in = get_irn_n(node, i);
- ir_node *new_in = get_new_node(in);
- set_irn_n(new_node, i, new_in);
- }
-
- /* Now the new node is complete. We can add it to the hash table for CSE. */
- add_identities(new_irg->value_table, new_node);
-}
-
-/**
- * Copies the graph reachable from current_ir_graph->end to the obstack
- * in current_ir_graph and fixes the environment.
- * Then fixes the fields in current_ir_graph containing nodes of the
- * graph.
- *
- * @param copy_node_nr If non-zero, the node number will be copied
- */
-static void copy_graph_env(ir_graph *irg)
-{
- ir_node *old_end;
- ir_node *new_anchor;
- ir_phase *old_ph;
- int i;
-
- /* init the new_phases array */
- for (i = PHASE_NOT_IRG_MANAGED+1; i < PHASE_LAST; i++) {
- old_ph = get_irg_phase(irg, i);
- if (old_ph == NULL) {
- new_phases[i] = NULL;
- } else {
- new_phases[i] = xmalloc(sizeof(ir_phase));
- phase_init(new_phases[i], "", irg, old_ph->growth_factor,
- old_ph->data_init, old_ph->priv);
- }
- }
-
- /* remove end_except and end_reg nodes */
- old_end = get_irg_end(irg);
- set_irg_end_except(irg, old_end);
- set_irg_end_reg (irg, old_end);
-
- /* copy nodes */
- irg_walk(irg->anchor, copy_node_with_number, set_preds, irg);
-
- /* fix the anchor */
- new_anchor = get_new_node(irg->anchor);
- assert(new_anchor != NULL);
- irg->anchor = new_anchor;
-
- /* copy the new phases into the irg */
- for (i = PHASE_NOT_IRG_MANAGED+1; i < PHASE_LAST; i++) {
- old_ph = get_irg_phase(irg, i);
- if (old_ph == NULL)
- continue;
-
- free_irg_phase(irg, i);
- irg->phases[i] = new_phases[i];
- }
-
- free_End(old_end);
-}
-
-/**
- * Copies all reachable nodes to a new obstack. Removes bad inputs
- * from block nodes and the corresponding inputs from Phi nodes.
- * Merges single exit blocks with single entry blocks and removes
- * 1-input Phis.
- * Adds all new nodes to a new hash table for CSE. Does not
- * perform CSE, so the hash table might contain common subexpressions.
- */
-void dead_node_elimination(ir_graph *irg)
-{
- ir_graph *rem;
-#ifdef INTERPROCEDURAL_VIEW
- int rem_ipview = get_interprocedural_view();
-#endif
- struct obstack *graveyard_obst = NULL;
- struct obstack *rebirth_obst = NULL;
-
- edges_deactivate(irg);
-
- /* inform statistics that we started a dead-node elimination run */
- hook_dead_node_elim(irg, 1);
-
- /* Remember external state of current_ir_graph. */
- rem = current_ir_graph;
- current_ir_graph = irg;
-#ifdef INTERPROCEDURAL_VIEW
- set_interprocedural_view(0);
-#endif
-
- assert(get_irg_phase_state(irg) != phase_building);
-
- /* Handle graph state */
- free_callee_info(irg);
- free_irg_outs(irg);
- free_trouts();
- free_loop_information(irg);
- set_irg_doms_inconsistent(irg);
-
- /* A quiet place, where the old obstack can rest in peace,
- until it will be cremated. */
- graveyard_obst = irg->obst;
-
- /* A new obstack, where the reachable nodes will be copied to. */
- rebirth_obst = XMALLOC(struct obstack);
- irg->obst = rebirth_obst;
- obstack_init(irg->obst);
- irg->last_node_idx = 0;
-
- /* We also need a new value table for CSE */
- del_identities(irg->value_table);
- irg->value_table = new_identities();
-
- /* Copy the graph from the old to the new obstack */
- copy_graph_env(irg);
-
- /* Free memory from old unoptimized obstack */
- obstack_free(graveyard_obst, 0); /* First empty the obstack ... */
- xfree(graveyard_obst); /* ... then free it. */
-
- /* inform statistics that the run is over */
- hook_dead_node_elim(irg, 0);
-
- current_ir_graph = rem;
-#ifdef INTERPROCEDURAL_VIEW
- set_interprocedural_view(rem_ipview);
-#endif
-}
-
-ir_graph_pass_t *dead_node_elimination_pass(const char *name)
-{
- return def_graph_pass(name ? name : "dce", dead_node_elimination);
-}
-
-/*
- __ _ __ __
- (_ __ 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;
- (void) irg;
-
- /* Create a new map before the dead node elimination is performed. */
- if (start) {
- sd->new_places = pmap_create_ex(pmap_count(sd->places));
- } else {
- /* Patch back all nodes if dead node elimination is over and something is to be done. */
- pmap_destroy(sd->places);
- sd->places = sd->new_places;
- sd->new_places = NULL;
- }
-}
-
-/**
- * Hook called when dead node elimination replaces old by nw.
- */
-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);
- (void) irg;
-
- /* 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(survive_dce_t);
- 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);
- xfree(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 = OALLOC(&sd->obst, survive_dce_list_t);
-
- nw->next = curr;
- nw->place = place;
-
- pmap_insert(sd->places, irn, nw);
- }
-}
-