2 * Interblock liveness analysis.
3 * @author Sebastian Hack
11 #include "iredges_t.h"
13 #include "irprintf_t.h"
19 #include "besched_t.h"
21 #define DBG_MODULE "firm.be.liveness"
23 #define LV_STD_SIZE 128
24 #define LV_USE_BINARY_SEARCH
25 #undef LV_INTESIVE_CHECKS
27 static INLINE int is_liveness_node(const ir_node *irn)
29 switch(get_irn_opcode(irn)) {
40 int (be_lv_next_irn)(const struct _be_lv_t *lv, const ir_node *bl, unsigned flags, int i)
42 return _be_lv_next_irn(lv, bl, flags, i);
45 const ir_node * (be_lv_get_irn)(const struct _be_lv_t *lv, const ir_node *bl, int i)
47 return _be_lv_get_irn(lv, bl, i);
50 int (be_is_live_in)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
52 return _be_is_live_xxx(lv, block, irn, be_lv_state_in);
55 int (be_is_live_out)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
57 return _be_is_live_xxx(lv, block, irn, be_lv_state_out);
60 int (be_is_live_end)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
62 return _be_is_live_xxx(lv, block, irn, be_lv_state_end);
66 #ifdef LV_USE_BINARY_SEARCH
67 static INLINE unsigned _be_liveness_bsearch(struct _be_lv_info_t *arr, unsigned idx)
69 struct _be_lv_info_t *payload = arr + 1;
71 unsigned n = arr[0].u.head.n_members;
80 if(idx < payload[0].u.node.idx)
83 if(idx > payload[n - 1].u.node.idx)
87 /* start a binary search for the requested node. */
89 int md = lo + ((hi - lo) >> 1);
90 unsigned md_idx = payload[md].u.node.idx;
98 assert(payload[res].u.node.idx == idx);
105 #ifdef LV_INTESIVE_CHECKS
108 for(i = res; i < n; ++i)
109 assert(payload[i].u.node.idx >= idx);
111 for(i = 0; i < res; ++i)
112 assert(payload[i].u.node.idx < idx);
122 * This function searches linearly for the node in the array.
124 static INLINE unsigned _be_liveness_bsearch(struct _be_lv_info_t *arr, unsigned idx) {
125 unsigned n = arr[0].u.head.n_members;
128 for(i = 0; i < n; ++i) {
129 if(arr[i + 1].u.node.idx == idx)
137 struct _be_lv_info_node_t *be_lv_get(const struct _be_lv_t *li, const ir_node *bl, const ir_node *irn)
139 struct _be_lv_info_t *irn_live = phase_get_irn_data(&li->ph, bl);
142 unsigned idx = get_irn_idx(irn);
144 /* Get the position of the index in the array. */
145 int pos = _be_liveness_bsearch(irn_live, idx);
147 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
148 struct _be_lv_info_node_t *res = &irn_live[pos + 1].u.node;
150 /* Check, if the irn is in deed in the array. */
158 static struct _be_lv_info_node_t *be_lv_get_or_set(struct _be_lv_t *li, ir_node *bl, ir_node *irn)
160 struct _be_lv_info_t *irn_live = phase_get_or_set_irn_data(&li->ph, bl);
162 unsigned idx = get_irn_idx(irn);
164 /* Get the position of the index in the array. */
165 unsigned pos = _be_liveness_bsearch(irn_live, idx);
167 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
168 struct _be_lv_info_node_t *res = &irn_live[pos + 1].u.node;
170 /* Check, if the irn is in deed in the array. */
171 if(res->idx != idx) {
172 struct _be_lv_info_t *payload;
173 unsigned n_members = irn_live[0].u.head.n_members;
174 unsigned n_size = irn_live[0].u.head.n_size;
177 if(n_members == n_size - 1) {
178 unsigned new_size = 2 * n_size * sizeof(irn_live[0]);
179 struct _be_lv_info_t *nw = phase_alloc(&li->ph, new_size);
180 memcpy(nw, irn_live, new_size);
181 nw[0].u.head.n_size = new_size;
183 phase_set_irn_data(&li->ph, irn, nw);
186 payload = &irn_live[1];
187 for(i = n_members; i > pos; --i) {
188 payload[i] = payload[i - 1];
191 ++irn_live[0].u.head.n_members;
193 res = &payload[pos].u.node;
198 #ifdef LV_INTESIVE_CHECKS
201 unsigned n = irn_live[0].u.head.n_members;
203 struct _be_lv_info_t *payload = &irn_live[1];
205 for(i = 0; i < n; ++i) {
206 assert(payload[i].u.node.idx >= last);
207 last = payload[i].u.node.idx;
216 * Removes a node from the list of live variables of a block.
217 * @return 1 if the node was live at that block, 0 if not.
219 static int be_lv_remove(struct _be_lv_t *li, ir_node *bl, ir_node *irn)
221 struct _be_lv_info_t *irn_live = phase_get_irn_data(&li->ph, bl);
224 unsigned n = irn_live[0].u.head.n_members;
225 unsigned idx = get_irn_idx(irn);
226 unsigned pos = _be_liveness_bsearch(irn_live, idx);
227 struct _be_lv_info_t *payload = irn_live + 1;
228 struct _be_lv_info_node_t *res = &payload[pos].u.node;
230 /* The node is in deed in the block's array. Let's remove it. */
231 if(res->idx == idx) {
234 for(i = pos + 1; i < n; ++i)
235 payload[i - 1] = payload[i];
237 payload[n - 1].u.node.idx = 0;
238 payload[n - 1].u.node.flags = 0;
240 --irn_live[0].u.head.n_members;
241 DBG((li->dbg, LEVEL_3, "\tdeleting %+F from %+F at pos %d\n", irn, bl, pos));
249 static void register_node(be_lv_t *lv, const ir_node *irn)
251 unsigned idx = get_irn_idx(irn);
252 if(idx >= bitset_size(lv->nodes)) {
253 bitset_t *nw = bitset_malloc(2 * idx);
254 bitset_copy(nw, lv->nodes);
255 bitset_free(lv->nodes);
259 bitset_set(lv->nodes, idx);
263 * Mark a node as live-in in a block.
265 static INLINE void mark_live_in(be_lv_t *lv, ir_node *block, ir_node *irn)
267 struct _be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
268 DBG((lv->dbg, LEVEL_2, "marking %+F live in at %+F\n", irn, block));
269 n->flags |= be_lv_state_in;
270 register_node(lv, irn);
274 * Mark a node as live-out in a block.
276 static INLINE void mark_live_out(be_lv_t *lv, ir_node *block, ir_node *irn)
278 struct _be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
279 DBG((lv->dbg, LEVEL_2, "marking %+F live out at %+F\n", irn, block));
280 n->flags |= be_lv_state_out | be_lv_state_end;
281 register_node(lv, irn);
285 * Mark a node as live-end in a block.
287 static INLINE void mark_live_end(be_lv_t *lv, ir_node *block, ir_node *irn)
289 struct _be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
290 DBG((lv->dbg, LEVEL_2, "marking %+F live end at %+F\n", irn, block));
291 n->flags |= be_lv_state_end;
292 register_node(lv, irn);
296 * Mark a node (value) live out at a certain block. Do this also
297 * transitively, i.e. if the block is not the block of the value's
298 * definition, all predecessors are also marked live.
299 * @param def The node (value).
300 * @param block The block to mark the value live out of.
301 * @param visited A set were all visited blocks are recorded.
302 * @param is_true_out Is the node real out there or only live at the end
305 static void live_end_at_block(be_lv_t *lv, ir_node *def, ir_node *block, bitset_t *visited, int is_true_out)
307 mark_live_end(lv, block, def);
309 mark_live_out(lv, block, def);
311 if(!bitset_contains_irn(visited, block)) {
312 bitset_add_irn(visited, block);
315 * If this block is not the definition block, we have to go up
318 if(get_nodes_block(def) != block) {
321 mark_live_in(lv, block, def);
323 for(i = 0, n = get_Block_n_cfgpreds(block); i < n; ++i)
324 live_end_at_block(lv, def, get_Block_cfgpred_block(block, i), visited, 1);
330 struct _lv_walker_t {
336 * Liveness analysis for a value.
337 * This functions is meant to be called by a firm walker, to compute the
338 * set of all blocks a value is live in.
339 * @param irn The node (value).
340 * @param env Ignored.
342 static void liveness_for_node(ir_node *irn, void *data)
344 struct _lv_walker_t *walker = data;
345 be_lv_t *lv = walker->lv;
346 bitset_t *visited = walker->data;
347 const ir_edge_t *edge;
350 /* Don't compute liveness information for non-data nodes. */
351 if(!is_liveness_node(irn))
354 bitset_clear_all(visited);
355 def_block = get_nodes_block(irn);
357 /* Go over all uses of the value */
358 foreach_out_edge(irn, edge) {
359 ir_node *use = edge->src;
363 * If the usage is no data node, skip this use, since it does not
364 * affect the liveness of the node.
366 if(!is_liveness_node(use))
369 /* Get the block where the usage is in. */
370 use_block = get_nodes_block(use);
373 * If the use is a phi function, determine the corresponding block
374 * through which the value reaches the phi function and mark the
375 * value as live out of that block.
378 ir_node *pred_block = get_Block_cfgpred_block(use_block, edge->pos);
379 live_end_at_block(lv, irn, pred_block, visited, 0);
383 * Else, the value is live in at this block. Mark it and call live
384 * out on the predecessors.
386 else if(def_block != use_block) {
389 mark_live_in(lv, use_block, irn);
391 for(i = 0, n = get_Block_n_cfgpreds(use_block); i < n; ++i) {
392 ir_node *pred_block = get_Block_cfgpred_block(use_block, i);
393 live_end_at_block(lv, irn, pred_block, visited, 1);
399 static void lv_remove_irn_walker(ir_node *bl, void *data)
401 struct _lv_walker_t *w = data;
403 ir_node *irn = w->data;
404 be_lv_remove(lv, bl, irn);
407 static const char *lv_flags_to_str(unsigned flags)
409 static const char *states[] = {
420 return states[flags & 7];
423 static void lv_dump_block(void *context, FILE *f, const ir_node *bl)
426 be_lv_t *lv = context;
427 struct _be_lv_info_t *info = phase_get_irn_data(&lv->ph, bl);
429 fprintf(f, "liveness:\n");
431 unsigned n = info[0].u.head.n_members;
434 for(i = 0; i < n; ++i) {
435 struct _be_lv_info_node_t *n = &info[i+1].u.node;
436 ir_fprintf(f, "%s %+F\n", lv_flags_to_str(n->flags), get_idx_irn(lv->irg, n->idx));
442 static void *lv_phase_data_init(phase_t *phase, ir_node *irn, void *old)
444 struct _be_lv_info_t *info = phase_alloc(phase, LV_STD_SIZE * sizeof(info[0]));
445 memset(info, 0, LV_STD_SIZE * sizeof(info[0]));
446 info[0].u.head.n_size = LV_STD_SIZE - 1;
450 static void compute_liveness(be_lv_t *lv)
452 struct _lv_walker_t w;
454 w.data = bitset_malloc(get_irg_last_idx(lv->irg));
455 irg_walk_graph(lv->irg, liveness_for_node, NULL, &w);
459 /* Compute the inter block liveness for a graph. */
460 be_lv_t *be_liveness(ir_graph *irg)
462 be_lv_t *lv = xmalloc(sizeof(lv[0]));
464 memset(lv, 0, sizeof(lv[0]));
465 FIRM_DBG_REGISTER(lv->dbg, DBG_MODULE);
467 lv->nodes = bitset_malloc(2 * get_irg_last_idx(irg));
468 lv->hook_info.context = lv;
469 lv->hook_info.hook._hook_node_info = lv_dump_block;
470 register_hook(hook_node_info, &lv->hook_info);
471 phase_init(&lv->ph, "liveness", irg, PHASE_DEFAULT_GROWTH, lv_phase_data_init);
472 compute_liveness(lv);
477 void be_liveness_recompute(be_lv_t *lv)
479 unsigned last_idx = get_irg_last_idx(lv->irg);
480 if(last_idx >= bitset_size(lv->nodes)) {
481 bitset_free(lv->nodes);
482 lv->nodes = bitset_malloc(last_idx * 2);
486 bitset_clear_all(lv->nodes);
489 phase_init(&lv->ph, "liveness", lv->irg, PHASE_DEFAULT_GROWTH, lv_phase_data_init);
490 compute_liveness(lv);
494 void be_liveness_free(be_lv_t *lv)
496 unregister_hook(hook_node_info, &lv->hook_info);
498 bitset_free(lv->nodes);
502 void be_liveness_remove(be_lv_t *lv, ir_node *irn)
504 unsigned idx = get_irn_idx(irn);
505 struct _lv_walker_t w;
508 * Removes a single irn from the liveness information.
509 * Since an irn can only be live at blocks dominated by the block of its
510 * definition, we only have to process that dominance subtree.
514 dom_tree_walk(get_nodes_block(irn), lv_remove_irn_walker, NULL, &w);
515 if(idx <= bitset_size(lv->nodes))
516 bitset_clear(lv->nodes, idx);
519 void be_liveness_introduce(be_lv_t *lv, ir_node *irn)
521 struct _lv_walker_t w;
523 w.data = bitset_malloc(get_irg_last_idx(lv->irg));
524 liveness_for_node(irn, &w);
528 void be_liveness_update(be_lv_t *lv, ir_node *irn)
530 be_liveness_remove(lv, irn);
531 be_liveness_introduce(lv, irn);
534 static void lv_add_missing_walker(ir_node *irn, void *data)
536 struct _lv_walker_t *w = data;
537 if(!is_Block(irn) && !bitset_contains_irn(w->lv->nodes, irn)) {
538 liveness_for_node(irn, w);
542 void be_liveness_add_missing(be_lv_t *lv)
544 struct _lv_walker_t w;
546 w.data = bitset_malloc(get_irg_last_idx(lv->irg));
547 irg_walk_graph(lv->irg, lv_add_missing_walker, NULL, &w);
551 static void lv_check_walker(ir_node *bl, void *data)
553 struct _lv_walker_t *w = data;
555 be_lv_t *fresh = w->data;
557 struct _be_lv_info_t *curr = phase_get_irn_data(&lv->ph, bl);
558 struct _be_lv_info_t *fr = phase_get_irn_data(&fresh->ph, bl);
560 if(!fr && curr && curr[0].u.head.n_members > 0) {
563 ir_fprintf(stderr, "%+F liveness should be empty but current liveness contains:\n", bl);
564 for(i = 0; i < curr[0].u.head.n_members; ++i) {
565 ir_fprintf(stderr, "\t%+F\n", get_idx_irn(lv->irg, curr[1 + i].u.node.idx));
570 unsigned n_curr = curr[0].u.head.n_members;
571 unsigned n_fresh = fr[0].u.head.n_members;
575 if(n_curr != n_fresh) {
576 ir_fprintf(stderr, "%+F: liveness set sizes differ. curr %d, correct %d\n", bl, n_curr, n_fresh);
578 ir_fprintf(stderr, "current:\n");
579 for(i = 0; i < n_curr; ++i) {
580 struct _be_lv_info_node_t *n = &curr[1 + i].u.node;
581 ir_fprintf(stderr, "%+F %u %+F %s\n", bl, i, get_idx_irn(lv->irg, n->idx), lv_flags_to_str(n->flags));
584 ir_fprintf(stderr, "correct:\n");
585 for(i = 0; i < n_fresh; ++i) {
586 struct _be_lv_info_node_t *n = &fr[1 + i].u.node;
587 ir_fprintf(stderr, "%+F %u %+F %s\n", bl, i, get_idx_irn(lv->irg, n->idx), lv_flags_to_str(n->flags));
593 void be_liveness_check(be_lv_t *lv)
595 struct _lv_walker_t w;
596 be_lv_t *fresh = be_liveness(lv->irg);
600 irg_block_walk_graph(lv->irg, lv_check_walker, NULL, &w);
601 be_liveness_free(fresh);
605 static void lv_dump_block_walker(ir_node *irn, void *data)
607 struct _lv_walker_t *w = data;
609 lv_dump_block(w->lv, w->data, irn);
613 /* Dump the liveness information for a graph. */
614 void be_liveness_dump(const be_lv_t *lv, FILE *f)
616 struct _lv_walker_t w;
618 w.lv = (be_lv_t *) lv;
620 irg_block_walk_graph(lv->irg, lv_dump_block_walker, NULL, &w);
623 /* Dump the liveness information for a graph. */
624 void be_liveness_dumpto(const be_lv_t *lv, const char *cls_name)
628 ir_snprintf(buf, sizeof(buf), "%F_%s-live.txt", lv->irg, cls_name);
629 if((f = fopen(buf, "wt")) != NULL) {
630 be_liveness_dump(lv, f);
636 * Walker: checks the every predecessors of a node dominate
639 static void dom_check(ir_node *irn, void *data)
641 int *problem_found = data;
643 if(!is_Block(irn) && irn != get_irg_end(get_irn_irg(irn))) {
645 ir_node *bl = get_nodes_block(irn);
647 for(i = 0, n = get_irn_arity(irn); i < n; ++i) {
648 ir_node *op = get_irn_n(irn, i);
649 ir_node *def_bl = get_nodes_block(op);
650 ir_node *use_bl = bl;
653 use_bl = get_Block_cfgpred_block(bl, i);
655 if(get_irn_opcode(use_bl) != iro_Bad
656 && get_irn_opcode(def_bl) != iro_Bad
657 && !block_dominates(def_bl, use_bl)) {
658 ir_fprintf(stderr, "Verify warning: %+F in %+F must dominate %+F for user %+F (%s)\n", op, def_bl, use_bl, irn, get_irg_dump_name(get_irn_irg(op)));
665 /* Check, if the SSA dominance property is fulfilled. */
666 int be_check_dominance(ir_graph *irg)
668 int problem_found = 0;
671 irg_walk_graph(irg, dom_check, NULL, &problem_found);
673 return !problem_found;
676 pset *be_liveness_transfer(const arch_env_t *arch_env, const arch_register_class_t *cls, ir_node *irn, pset *live)
679 FIRM_DBG_REGISTER(firm_dbg_module_t *dbg, DBG_MODULE);
683 DBG((dbg, LEVEL_1, "%+F\n", irn));
684 for(x = pset_first(live); x; x = pset_next(live))
685 DBG((dbg, LEVEL_1, "\tlive: %+F\n", x));
688 /* You should better break out of your loop when hitting the first phi function. */
689 assert(!is_Phi(irn) && "liveness_transfer produces invalid results for phi nodes");
691 if(arch_irn_consider_in_reg_alloc(arch_env, cls, irn)) {
692 ir_node *del = pset_remove_ptr(live, irn);
696 for(i = 0, n = get_irn_arity(irn); i < n; ++i) {
697 ir_node *op = get_irn_n(irn, i);
699 if(arch_irn_consider_in_reg_alloc(arch_env, cls, op))
700 pset_insert_ptr(live, op);
706 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)
709 be_lv_foreach(lv, bl, be_lv_state_end, i) {
710 ir_node *irn = be_lv_get_irn(lv, bl, i);
711 if(arch_irn_consider_in_reg_alloc(arch_env, cls, irn))
712 pset_insert_ptr(live, irn);
718 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)
720 const ir_node *bl = is_Block(pos) ? pos : get_nodes_block(pos);
723 be_liveness_end_of_block(lv, arch_env, cls, bl, live);
724 sched_foreach_reverse(bl, irn) {
726 * If we encounter the node we want to insert the Perm after,
727 * exit immediately, so that this node is still live
732 be_liveness_transfer(arch_env, cls, irn, live);