2 * Interblock liveness analysis.
3 * @author Sebastian Hack
11 #include "iredges_t.h"
13 #include "irprintf_t.h"
18 #include "besched_t.h"
20 #define DBG_MODULE "firm.be.liveness"
22 #define LV_STD_SIZE 128
23 #define LV_USE_BINARY_SEARCH
24 #undef LV_INTESIVE_CHECKS
26 static INLINE int is_liveness_node(const ir_node *irn)
28 switch(get_irn_opcode(irn)) {
39 int (be_lv_next_irn)(const struct _be_lv_t *lv, const ir_node *bl, unsigned flags, int i)
41 return _be_lv_next_irn(lv, bl, flags, i);
44 const ir_node * (be_lv_get_irn)(const struct _be_lv_t *lv, const ir_node *bl, int i)
46 return _be_lv_get_irn(lv, bl, i);
49 int (be_is_live_in)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
51 return _be_is_live_xxx(lv, block, irn, be_lv_state_in);
54 int (be_is_live_out)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
56 return _be_is_live_xxx(lv, block, irn, be_lv_state_out);
59 int (be_is_live_end)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
61 return _be_is_live_xxx(lv, block, irn, be_lv_state_end);
65 #ifdef LV_USE_BINARY_SEARCH
66 static INLINE unsigned _be_liveness_bsearch(struct _be_lv_info_t *arr, unsigned idx)
68 struct _be_lv_info_t *payload = arr + 1;
70 unsigned n = arr[0].u.head.n_members;
79 if(idx < payload[0].u.node.idx)
82 if(idx > payload[n - 1].u.node.idx)
86 /* start a binary search for the requested node. */
88 int md = lo + ((hi - lo) >> 1);
89 unsigned md_idx = payload[md].u.node.idx;
97 assert(payload[res].u.node.idx == idx);
104 #ifdef LV_INTESIVE_CHECKS
107 for(i = res; i < n; ++i)
108 assert(payload[i].u.node.idx >= idx);
110 for(i = 0; i < res; ++i)
111 assert(payload[i].u.node.idx < idx);
121 * This function searches linearily for the node in the array.
123 static INLINE unsigned _be_liveness_bsearch(struct _be_lv_info_t *arr, unsigned idx) {
124 unsigned n = arr[0].u.head.n_members;
127 for(i = 0; i < n; ++i) {
128 if(arr[i + 1].u.node.idx == idx)
136 struct _be_lv_info_node_t *be_lv_get(const struct _be_lv_t *li, const ir_node *bl, const ir_node *irn)
138 struct _be_lv_info_t *irn_live = phase_get_irn_data(&li->ph, bl);
141 unsigned idx = get_irn_idx(irn);
143 /* Get the position of the index in the array. */
144 int pos = _be_liveness_bsearch(irn_live, idx);
146 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
147 struct _be_lv_info_node_t *res = &irn_live[pos + 1].u.node;
149 /* Check, if the irn is in deed in the array. */
157 static struct _be_lv_info_node_t *be_lv_get_or_set(struct _be_lv_t *li, ir_node *bl, ir_node *irn)
159 struct _be_lv_info_t *irn_live = phase_get_or_set_irn_data(&li->ph, bl);
161 unsigned idx = get_irn_idx(irn);
163 /* Get the position of the index in the array. */
164 unsigned pos = _be_liveness_bsearch(irn_live, idx);
166 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
167 struct _be_lv_info_node_t *res = &irn_live[pos + 1].u.node;
169 /* Check, if the irn is in deed in the array. */
170 if(res->idx != idx) {
171 struct _be_lv_info_t *payload;
172 unsigned n_members = irn_live[0].u.head.n_members;
173 unsigned n_size = irn_live[0].u.head.n_size;
176 if(n_members == n_size - 1) {
177 unsigned new_size = 2 * n_size * sizeof(irn_live[0]);
178 struct _be_lv_info_t *nw = phase_alloc(&li->ph, new_size);
179 memcpy(nw, irn_live, new_size);
180 nw[0].u.head.n_size = new_size;
182 phase_set_irn_data(&li->ph, irn, nw);
185 payload = &irn_live[1];
186 for(i = n_members; i > pos; --i) {
187 payload[i] = payload[i - 1];
190 ++irn_live[0].u.head.n_members;
192 res = &payload[pos].u.node;
197 #ifdef LV_INTESIVE_CHECKS
200 unsigned n = irn_live[0].u.head.n_members;
202 struct _be_lv_info_t *payload = &irn_live[1];
204 for(i = 0; i < n; ++i) {
205 assert(payload[i].u.node.idx >= last);
206 last = payload[i].u.node.idx;
215 * Removes a node from the list of live variables of a block.
216 * @return 1 if the node was live at that block, 0 if not.
218 static int be_lv_remove(struct _be_lv_t *li, ir_node *bl, ir_node *irn)
220 struct _be_lv_info_t *irn_live = phase_get_irn_data(&li->ph, bl);
223 unsigned n = irn_live[0].u.head.n_members;
224 unsigned idx = get_irn_idx(irn);
225 unsigned pos = _be_liveness_bsearch(irn_live, idx);
226 struct _be_lv_info_t *payload = irn_live + 1;
227 struct _be_lv_info_node_t *res = &payload[pos].u.node;
229 /* The node is in deed in the block's array. Let's remove it. */
230 if(res->idx == idx) {
233 for(i = pos + 1; i < n; ++i)
234 payload[i - 1] = payload[i];
236 payload[n - 1].u.node.idx = 0;
237 payload[n - 1].u.node.flags = 0;
239 --irn_live[0].u.head.n_members;
240 DBG((li->dbg, LEVEL_3, "\tdeleting %+F from %+F at pos %d\n", irn, bl, pos));
248 static void register_node(be_lv_t *lv, const ir_node *irn)
250 unsigned idx = get_irn_idx(irn);
251 if(idx >= bitset_size(lv->nodes)) {
252 bitset_t *nw = bitset_malloc(2 * idx);
253 bitset_copy(nw, lv->nodes);
254 bitset_free(lv->nodes);
258 bitset_set(lv->nodes, idx);
262 * Mark a node as live-in in a block.
264 static INLINE void mark_live_in(be_lv_t *lv, ir_node *block, ir_node *irn)
266 struct _be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
267 DBG((lv->dbg, LEVEL_2, "marking %+F live in at %+F\n", irn, block));
268 n->flags |= be_lv_state_in;
269 register_node(lv, irn);
273 * Mark a node as live-out in a block.
275 static INLINE void mark_live_out(be_lv_t *lv, ir_node *block, ir_node *irn)
277 struct _be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
278 DBG((lv->dbg, LEVEL_2, "marking %+F live out at %+F\n", irn, block));
279 n->flags |= be_lv_state_out | be_lv_state_end;
280 register_node(lv, irn);
284 * Mark a node as live-end in a block.
286 static INLINE void mark_live_end(be_lv_t *lv, ir_node *block, ir_node *irn)
288 struct _be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
289 DBG((lv->dbg, LEVEL_2, "marking %+F live end at %+F\n", irn, block));
290 n->flags |= be_lv_state_end;
291 register_node(lv, irn);
295 * Mark a node (value) live out at a certain block. Do this also
296 * transitively, i.e. if the block is not the block of the value's
297 * definition, all predecessors are also marked live.
298 * @param def The node (value).
299 * @param block The block to mark the value live out of.
300 * @param visited A set were all visited blocks are recorded.
301 * @param is_true_out Is the node real out there or only live at the end
304 static void live_end_at_block(be_lv_t *lv, ir_node *def, ir_node *block, bitset_t *visited, int is_true_out)
306 mark_live_end(lv, block, def);
308 mark_live_out(lv, block, def);
310 if(!bitset_contains_irn(visited, block)) {
311 bitset_add_irn(visited, block);
314 * If this block is not the definition block, we have to go up
317 if(get_nodes_block(def) != block) {
320 mark_live_in(lv, block, def);
322 for(i = 0, n = get_Block_n_cfgpreds(block); i < n; ++i)
323 live_end_at_block(lv, def, get_Block_cfgpred_block(block, i), visited, 1);
329 struct _lv_walker_t {
335 * Liveness analysis for a value.
336 * This functions is meant to be called by a firm walker, to compute the
337 * set of all blocks a value is live in.
338 * @param irn The node (value).
339 * @param env Ignored.
341 static void liveness_for_node(ir_node *irn, void *data)
343 struct _lv_walker_t *walker = data;
344 be_lv_t *lv = walker->lv;
345 bitset_t *visited = walker->data;
346 const ir_edge_t *edge;
349 /* Don't compute liveness information for non-data nodes. */
350 if(!is_liveness_node(irn))
353 bitset_clear_all(visited);
354 def_block = get_nodes_block(irn);
356 /* Go over all uses of the value */
357 foreach_out_edge(irn, edge) {
358 ir_node *use = edge->src;
362 * If the usage is no data node, skip this use, since it does not
363 * affect the liveness of the node.
365 if(!is_liveness_node(use))
368 /* Get the block where the usage is in. */
369 use_block = get_nodes_block(use);
372 * If the use is a phi function, determine the corresponding block
373 * through which the value reaches the phi function and mark the
374 * value as live out of that block.
377 ir_node *pred_block = get_Block_cfgpred_block(use_block, edge->pos);
378 live_end_at_block(lv, irn, pred_block, visited, 0);
382 * Else, the value is live in at this block. Mark it and call live
383 * out on the predecessors.
385 else if(def_block != use_block) {
388 mark_live_in(lv, use_block, irn);
390 for(i = 0, n = get_Block_n_cfgpreds(use_block); i < n; ++i) {
391 ir_node *pred_block = get_Block_cfgpred_block(use_block, i);
392 live_end_at_block(lv, irn, pred_block, visited, 1);
398 static void lv_remove_irn_walker(ir_node *bl, void *data)
400 struct _lv_walker_t *w = data;
402 ir_node *irn = w->data;
403 be_lv_remove(lv, bl, irn);
406 static const char *lv_flags_to_str(unsigned flags)
408 static const char *states[] = {
419 return states[flags & 7];
422 static void lv_dump_block(void *context, FILE *f, const ir_node *bl)
425 be_lv_t *lv = context;
426 struct _be_lv_info_t *info = phase_get_irn_data(&lv->ph, bl);
428 fprintf(f, "liveness:\n");
430 unsigned n = info[0].u.head.n_members;
433 for(i = 0; i < n; ++i) {
434 struct _be_lv_info_node_t *n = &info[i+1].u.node;
435 ir_fprintf(f, "%s %+F\n", lv_flags_to_str(n->flags), get_idx_irn(lv->irg, n->idx));
441 static void *lv_phase_data_init(phase_t *phase, ir_node *irn, void *old)
443 struct _be_lv_info_t *info = phase_alloc(phase, LV_STD_SIZE * sizeof(info[0]));
444 memset(info, 0, LV_STD_SIZE * sizeof(info[0]));
445 info[0].u.head.n_size = LV_STD_SIZE - 1;
449 static void compute_liveness(be_lv_t *lv)
451 struct _lv_walker_t w;
453 w.data = bitset_malloc(get_irg_last_idx(lv->irg));
454 irg_walk_graph(lv->irg, liveness_for_node, NULL, &w);
458 /* Compute the inter block liveness for a graph. */
459 be_lv_t *be_liveness(ir_graph *irg)
461 be_lv_t *lv = xmalloc(sizeof(lv[0]));
463 memset(lv, 0, sizeof(lv[0]));
464 FIRM_DBG_REGISTER(lv->dbg, DBG_MODULE);
466 lv->nodes = bitset_malloc(2 * get_irg_last_idx(irg));
467 lv->hook_info.context = lv;
468 lv->hook_info.hook._hook_node_info = lv_dump_block;
469 register_hook(hook_node_info, &lv->hook_info);
470 phase_init(&lv->ph, "liveness", irg, PHASE_DEFAULT_GROWTH, lv_phase_data_init);
471 compute_liveness(lv);
476 void be_liveness_recompute(be_lv_t *lv)
478 unsigned last_idx = get_irg_last_idx(lv->irg);
479 if(last_idx >= bitset_size(lv->nodes)) {
480 bitset_free(lv->nodes);
481 lv->nodes = bitset_malloc(last_idx * 2);
485 bitset_clear_all(lv->nodes);
488 phase_init(&lv->ph, "liveness", lv->irg, PHASE_DEFAULT_GROWTH, lv_phase_data_init);
489 compute_liveness(lv);
493 void be_liveness_free(be_lv_t *lv)
495 unregister_hook(hook_node_info, &lv->hook_info);
497 bitset_free(lv->nodes);
501 void be_liveness_remove(be_lv_t *lv, ir_node *irn)
503 unsigned idx = get_irn_idx(irn);
504 struct _lv_walker_t w;
507 * Removes a single irn from the liveness information.
508 * Since an irn can only be live at blocks dominated by the block of its
509 * definition, we only have to process that dominance subtree.
513 dom_tree_walk(get_nodes_block(irn), lv_remove_irn_walker, NULL, &w);
514 if(idx <= bitset_size(lv->nodes))
515 bitset_clear(lv->nodes, idx);
518 void be_liveness_introduce(be_lv_t *lv, ir_node *irn)
520 struct _lv_walker_t w;
522 w.data = bitset_malloc(get_irg_last_idx(lv->irg));
523 liveness_for_node(irn, &w);
527 void be_liveness_update(be_lv_t *lv, ir_node *irn)
529 be_liveness_remove(lv, irn);
530 be_liveness_introduce(lv, irn);
533 static void lv_add_missing_walker(ir_node *irn, void *data)
535 struct _lv_walker_t *w = data;
536 if(!is_Block(irn) && !bitset_contains_irn(w->lv->nodes, irn)) {
537 liveness_for_node(irn, w);
541 void be_liveness_add_missing(be_lv_t *lv)
543 struct _lv_walker_t w;
545 w.data = bitset_malloc(get_irg_last_idx(lv->irg));
546 irg_walk_graph(lv->irg, lv_add_missing_walker, NULL, &w);
550 static void lv_check_walker(ir_node *bl, void *data)
552 struct _lv_walker_t *w = data;
554 be_lv_t *fresh = w->data;
556 struct _be_lv_info_t *curr = phase_get_irn_data(&lv->ph, bl);
557 struct _be_lv_info_t *fr = phase_get_irn_data(&fresh->ph, bl);
559 if(!fr && curr && curr[0].u.head.n_members > 0) {
562 ir_fprintf(stderr, "%+F liveness should be empty but current liveness contains:\n", bl);
563 for(i = 0; i < curr[0].u.head.n_members; ++i) {
564 ir_fprintf(stderr, "\t%+F\n", get_idx_irn(lv->irg, curr[1 + i].u.node.idx));
569 unsigned n_curr = curr[0].u.head.n_members;
570 unsigned n_fresh = fr[0].u.head.n_members;
574 if(n_curr != n_fresh) {
575 ir_fprintf(stderr, "%+F: liveness set sizes differ. curr %d, correct %d\n", bl, n_curr, n_fresh);
577 ir_fprintf(stderr, "current:\n");
578 for(i = 0; i < n_curr; ++i) {
579 struct _be_lv_info_node_t *n = &curr[1 + i].u.node;
580 ir_fprintf(stderr, "%+F %u %+F %s\n", bl, i, get_idx_irn(lv->irg, n->idx), lv_flags_to_str(n->flags));
583 ir_fprintf(stderr, "correct:\n");
584 for(i = 0; i < n_fresh; ++i) {
585 struct _be_lv_info_node_t *n = &fr[1 + i].u.node;
586 ir_fprintf(stderr, "%+F %u %+F %s\n", bl, i, get_idx_irn(lv->irg, n->idx), lv_flags_to_str(n->flags));
592 void be_liveness_check(be_lv_t *lv)
594 struct _lv_walker_t w;
595 be_lv_t *fresh = be_liveness(lv->irg);
599 irg_block_walk_graph(lv->irg, lv_check_walker, NULL, &w);
600 be_liveness_free(fresh);
604 static void lv_dump_block_walker(ir_node *irn, void *data)
606 struct _lv_walker_t *w = data;
608 lv_dump_block(w->lv, w->data, irn);
612 /* Dump the liveness information for a graph. */
613 void be_liveness_dump(const be_lv_t *lv, FILE *f)
615 struct _lv_walker_t w;
617 w.lv = (be_lv_t *) lv;
619 irg_block_walk_graph(lv->irg, lv_dump_block_walker, NULL, &w);
622 /* Dump the liveness information for a graph. */
623 void be_liveness_dumpto(const be_lv_t *lv, const char *cls_name)
627 ir_snprintf(buf, sizeof(buf), "%F_%s-live.txt", lv->irg, cls_name);
628 if((f = fopen(buf, "wt")) != NULL) {
629 be_liveness_dump(lv, f);
635 * Walker: checks the every predecessors of a node dominate
638 static void dom_check(ir_node *irn, void *data)
640 if(!is_Block(irn) && irn != get_irg_end(get_irn_irg(irn))) {
642 ir_node *bl = get_nodes_block(irn);
644 for(i = 0, n = get_irn_arity(irn); i < n; ++i) {
645 ir_node *op = get_irn_n(irn, i);
646 ir_node *def_bl = get_nodes_block(op);
647 ir_node *use_bl = bl;
650 use_bl = get_Block_cfgpred_block(bl, i);
652 if(!block_dominates(def_bl, use_bl)) {
653 ir_fprintf(stderr, "%+F in %+F must dominate %+F for user %+F\n", op, def_bl, use_bl, irn);
660 /* Check, if the SSA dominance property is fulfilled. */
661 void be_check_dominance(ir_graph *irg)
663 irg_walk_graph(irg, dom_check, NULL, NULL);
666 pset *be_liveness_transfer(const arch_env_t *arch_env, const arch_register_class_t *cls, ir_node *irn, pset *live)
670 FIRM_DBG_REGISTER(firm_dbg_module_t *dbg, DBG_MODULE);
673 DBG((dbg, LEVEL_1, "%+F\n", irn));
674 for(x = pset_first(live); x; x = pset_next(live))
675 DBG((dbg, LEVEL_1, "\tlive: %+F\n", x));
678 /* You should better break out of your loop when hitting the first phi function. */
679 assert(!is_Phi(irn) && "liveness_transfer produces invalid results for phi nodes");
681 if(arch_irn_consider_in_reg_alloc(arch_env, cls, irn)) {
682 ir_node *del = pset_remove_ptr(live, irn);
686 for(i = 0, n = get_irn_arity(irn); i < n; ++i) {
687 ir_node *op = get_irn_n(irn, i);
689 if(arch_irn_consider_in_reg_alloc(arch_env, cls, op))
690 pset_insert_ptr(live, op);
696 pset *be_liveness_end_of_block(const be_lv_t *lv, const arch_env_t *arch_env, const arch_register_class_t *cls, const ir_node *bl, pset *live)
699 be_lv_foreach(lv, bl, be_lv_state_end, i) {
700 ir_node *irn = be_lv_get_irn(lv, bl, i);
701 if(arch_irn_consider_in_reg_alloc(arch_env, cls, irn))
702 pset_insert_ptr(live, irn);
708 pset *be_liveness_nodes_live_at(const be_lv_t *lv, const arch_env_t *arch_env, const arch_register_class_t *cls, const ir_node *pos, pset *live)
710 const ir_node *bl = is_Block(pos) ? pos : get_nodes_block(pos);
713 be_liveness_end_of_block(lv, arch_env, cls, bl, live);
714 sched_foreach_reverse(bl, irn) {
716 * If we encounter the node we want to insert the Perm after,
717 * exit immediately, so that this node is still live
722 be_liveness_transfer(arch_env, cls, irn, live);