- * Copies the graph recursively, compacts the keep-alives of the end node.
- *
- * @param irg the graph to be copied
- * @param copy_node_nr If non-zero, the node number will be copied
- */
-static void copy_graph(ir_graph *irg, int copy_node_nr) {
- ir_node *oe, *ne, *ob, *nb, *om, *nm; /* old end, new end, old bad, new bad, old NoMem, new NoMem */
- ir_node *ka; /* keep alive */
- int i, irn_arity;
- unsigned long vfl;
-
- /* Some nodes must be copied by hand, sigh */
- vfl = get_irg_visited(irg);
- set_irg_visited(irg, vfl + 1);
-
- oe = get_irg_end(irg);
- mark_irn_visited(oe);
- /* copy the end node by hand, allocate dynamic in array! */
- ne = new_ir_node(get_irn_dbg_info(oe),
- irg,
- NULL,
- op_End,
- mode_X,
- -1,
- NULL);
- /* Copy the attributes. Well, there might be some in the future... */
- copy_node_attr(oe, ne);
- set_new_node(oe, ne);
-
- /* copy the Bad node */
- ob = get_irg_bad(irg);
- mark_irn_visited(ob);
- nb = new_ir_node(get_irn_dbg_info(ob),
- irg,
- NULL,
- op_Bad,
- mode_T,
- 0,
- NULL);
- copy_node_attr(ob, nb);
- set_new_node(ob, nb);
-
- /* copy the NoMem node */
- om = get_irg_no_mem(irg);
- mark_irn_visited(om);
- nm = new_ir_node(get_irn_dbg_info(om),
- irg,
- NULL,
- op_NoMem,
- mode_M,
- 0,
- NULL);
- copy_node_attr(om, nm);
- set_new_node(om, nm);
-
- /* copy the live nodes */
- set_irg_visited(irg, vfl);
- irg_walk(get_nodes_block(oe), copy_node, copy_preds, INT_TO_PTR(copy_node_nr));
-
- /* Note: from yet, the visited flag of the graph is equal to vfl + 1 */
-
- /* visit the anchors as well */
- for (i = get_irg_n_anchors(irg) - 1; i >= 0; --i) {
- ir_node *n = get_irg_anchor(irg, i);
-
- if (n && (get_irn_visited(n) <= vfl)) {
- set_irg_visited(irg, vfl);
- irg_walk(n, copy_node, copy_preds, INT_TO_PTR(copy_node_nr));
- }
- }
-
- /* copy_preds for the end node ... */
- set_nodes_block(ne, get_new_node(get_nodes_block(oe)));
-
- /*- ... and now the keep alives. -*/
- /* First pick the not marked block nodes and walk them. We must pick these
- first as else we will oversee blocks reachable from Phis. */
- irn_arity = get_End_n_keepalives(oe);
- for (i = 0; i < irn_arity; i++) {
- ka = get_End_keepalive(oe, i);
- if (is_Block(ka)) {
- if (get_irn_visited(ka) <= vfl) {
- /* We must keep the block alive and copy everything reachable */
- set_irg_visited(irg, vfl);
- irg_walk(ka, copy_node, copy_preds, INT_TO_PTR(copy_node_nr));
- }
- add_End_keepalive(ne, get_new_node(ka));
- }
- }
-
- /* Now pick other nodes. Here we will keep all! */
- irn_arity = get_End_n_keepalives(oe);
- for (i = 0; i < irn_arity; i++) {
- ka = get_End_keepalive(oe, i);
- if (!is_Block(ka)) {
- if (get_irn_visited(ka) <= vfl) {
- /* We didn't copy the node yet. */
- set_irg_visited(irg, vfl);
- irg_walk(ka, copy_node, copy_preds, INT_TO_PTR(copy_node_nr));
- }
- add_End_keepalive(ne, get_new_node(ka));
- }
- }
-
- /* start block sometimes only reached after keep alives */
- set_nodes_block(nb, get_new_node(get_nodes_block(ob)));
- set_nodes_block(nm, get_new_node(get_nodes_block(om)));
-}
-
-/**
- * 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(int copy_node_nr) {
- ir_graph *irg = current_ir_graph;
- ir_node *old_end, *new_anchor;
- int i;
-
- /* 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);
-
- /* Not all nodes remembered in irg might be reachable
- from the end node. Assure their link is set to NULL, so that
- we can test whether new nodes have been computed. */
- for (i = get_irg_n_anchors(irg) - 1; i >= 0; --i) {
- ir_node *n = get_irg_anchor(irg, i);
- if (n != NULL)
- set_new_node(n, NULL);
- }
- /* we use the block walk flag for removing Bads from Blocks ins. */
- inc_irg_block_visited(irg);
-
- /* copy the graph */
- copy_graph(irg, copy_node_nr);
-
- /* fix the anchor */
- old_end = get_irg_end(irg);
- new_anchor = new_Anchor(irg);
-
- for (i = get_irg_n_anchors(irg) - 1; i >= 0; --i) {
- ir_node *n = get_irg_anchor(irg, i);
- if (n)
- set_irn_n(new_anchor, i, get_new_node(n));
- }
- free_End(old_end);
- irg->anchor = new_anchor;
-
- /* ensure the new anchor is placed in the endblock */
- set_nodes_block(new_anchor, get_irg_end_block(irg));
-}
-
-/**
- * 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;
- assert(! edges_activated(irg) && "dead node elimination requires disabled edges");
-
- /* 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();
-
- /* @@@ so far we loose loops when copying */
- 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(sizeof(*rebirth_obst));
- 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(/*copy_node_nr=*/1);
-
- /* 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
-}
-
-/**
- * Relink bad predecessors of a block and store the old in array to the
- * link field. This function is called by relink_bad_predecessors().
- * The array of link field starts with the block operand at position 0.
- * If block has bad predecessors, create a new in array without bad preds.
- * Otherwise let in array untouched.
- */
-static void relink_bad_block_predecessors(ir_node *n, void *env) {
- ir_node **new_in, *irn;
- int i, new_irn_n, old_irn_arity, new_irn_arity = 0;
- (void) env;
-
- /* if link field of block is NULL, look for bad predecessors otherwise
- this is already done */
- if (is_Block(n) && get_irn_link(n) == NULL) {
- /* save old predecessors in link field (position 0 is the block operand)*/
- set_irn_link(n, get_irn_in(n));
-
- /* count predecessors without bad nodes */
- old_irn_arity = get_irn_arity(n);
- for (i = 0; i < old_irn_arity; i++)
- if (!is_Bad(get_irn_n(n, i)))
- ++new_irn_arity;
-
- /* arity changing: set new predecessors without bad nodes */
- if (new_irn_arity < old_irn_arity) {
- /* Get new predecessor array. We do not resize the array, as we must
- keep the old one to update Phis. */
- new_in = NEW_ARR_D(ir_node *, current_ir_graph->obst, (new_irn_arity+1));
-
- /* set new predecessors in array */
- new_in[0] = NULL;
- new_irn_n = 1;
- for (i = 0; i < old_irn_arity; i++) {
- irn = get_irn_n(n, i);
- if (!is_Bad(irn)) {
- new_in[new_irn_n] = irn;
- is_backedge(n, i) ? set_backedge(n, new_irn_n-1) : set_not_backedge(n, new_irn_n-1);
- ++new_irn_n;
- }
- }
- /* ARR_SETLEN(int, n->attr.block.backedge, new_irn_arity); */
- ARR_SHRINKLEN(n->attr.block.backedge, new_irn_arity);
- n->in = new_in;
- } /* ir node has bad predecessors */
- } /* Block is not relinked */
-}
-
-/**
- * Relinks Bad predecessors from Blocks and Phis called by walker
- * remove_bad_predecesors(). If n is a Block, call
- * relink_bad_block_redecessors(). If n is a Phi-node, call also the relinking
- * function of Phi's Block. If this block has bad predecessors, relink preds
- * of the Phi-node.
- */
-static void relink_bad_predecessors(ir_node *n, void *env) {
- ir_node *block, **old_in;
- int i, old_irn_arity, new_irn_arity;
-
- /* relink bad predecessors of a block */
- if (is_Block(n))
- relink_bad_block_predecessors(n, env);
-
- /* If Phi node relink its block and its predecessors */
- if (is_Phi(n)) {
- /* Relink predecessors of phi's block */
- block = get_nodes_block(n);
- if (get_irn_link(block) == NULL)
- relink_bad_block_predecessors(block, env);
-
- old_in = (ir_node **)get_irn_link(block); /* Of Phi's Block */
- old_irn_arity = ARR_LEN(old_in);
-
- /* Relink Phi predecessors if count of predecessors changed */
- if (old_irn_arity != ARR_LEN(get_irn_in(block))) {
- /* set new predecessors in array
- n->in[0] remains the same block */
- new_irn_arity = 1;
- for(i = 1; i < old_irn_arity; i++)
- if (!is_Bad(old_in[i])) {
- n->in[new_irn_arity] = n->in[i];
- is_backedge(n, i) ? set_backedge(n, new_irn_arity) : set_not_backedge(n, new_irn_arity);
- ++new_irn_arity;
- }
-
- ARR_SETLEN(ir_node *, n->in, new_irn_arity);
- ARR_SETLEN(int, n->attr.phi.u.backedge, new_irn_arity);
- }
- } /* n is a Phi node */
-}
-
-/*
- * Removes Bad Bad predecessors from Blocks and the corresponding
- * inputs to Phi nodes as in dead_node_elimination but without
- * copying the graph.
- * On walking up set the link field to NULL, on walking down call
- * relink_bad_predecessors() (This function stores the old in array
- * to the link field and sets a new in array if arity of predecessors
- * changes).
- */
-void remove_bad_predecessors(ir_graph *irg) {
- panic("Fix backedge handling first");
- irg_walk_graph(irg, firm_clear_link, relink_bad_predecessors, NULL);
-}
-
-
-/*
- __ _ __ __
- (_ __ 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(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;
-
-#ifndef FIRM_ENABLE_HOOKS
- assert(0 && "need hooks enabled");
-#endif
-
- 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.