2 * Copyright (C) 1995-2007 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
6 * This file may be distributed and/or modified under the terms of the
7 * GNU General Public License version 2 as published by the Free Software
8 * Foundation and appearing in the file LICENSE.GPL included in the
9 * packaging of this file.
11 * Licensees holding valid libFirm Professional Edition licenses may use
12 * this file in accordance with the libFirm Commercial License.
13 * Agreement provided with the Software.
15 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * @brief Interblock liveness analysis.
23 * @author Sebastian Hack
32 #include "iredges_t.h"
34 #include "irprintf_t.h"
40 #include "besched_t.h"
43 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
45 #define LV_STD_SIZE 128
46 #define LV_USE_BINARY_SEARCH
47 #undef LV_INTESIVE_CHECKS
49 static INLINE int is_liveness_node(const ir_node *irn)
51 switch(get_irn_opcode(irn)) {
62 int (be_lv_next_irn)(const struct _be_lv_t *lv, const ir_node *bl, unsigned flags, int i)
64 return _be_lv_next_irn(lv, bl, flags, i);
67 const ir_node * (be_lv_get_irn)(const struct _be_lv_t *lv, const ir_node *bl, int i)
69 return _be_lv_get_irn(lv, bl, i);
72 int (be_is_live_in)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
74 return _be_is_live_xxx(lv, block, irn, be_lv_state_in);
77 int (be_is_live_out)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
79 return _be_is_live_xxx(lv, block, irn, be_lv_state_out);
82 int (be_is_live_end)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
84 return _be_is_live_xxx(lv, block, irn, be_lv_state_end);
88 #ifdef LV_USE_BINARY_SEARCH
89 static INLINE unsigned _be_liveness_bsearch(struct _be_lv_info_t *arr, unsigned idx)
91 struct _be_lv_info_t *payload = arr + 1;
93 unsigned n = arr[0].u.head.n_members;
102 if(idx < payload[0].u.node.idx)
105 if(idx > payload[n - 1].u.node.idx)
109 /* start a binary search for the requested node. */
111 int md = lo + ((hi - lo) >> 1);
112 unsigned md_idx = payload[md].u.node.idx;
116 else if(idx < md_idx)
120 assert(payload[res].u.node.idx == idx);
127 #ifdef LV_INTESIVE_CHECKS
130 for(i = res; i < n; ++i)
131 assert(payload[i].u.node.idx >= idx);
133 for(i = 0; i < res; ++i)
134 assert(payload[i].u.node.idx < idx);
144 * This function searches linearly for the node in the array.
146 static INLINE unsigned _be_liveness_bsearch(struct _be_lv_info_t *arr, unsigned idx) {
147 unsigned n = arr[0].u.head.n_members;
150 for(i = 0; i < n; ++i) {
151 if(arr[i + 1].u.node.idx == idx)
159 struct _be_lv_info_node_t *be_lv_get(const struct _be_lv_t *li, const ir_node *bl, const ir_node *irn)
161 struct _be_lv_info_t *irn_live = phase_get_irn_data(&li->ph, bl);
164 unsigned idx = get_irn_idx(irn);
166 /* Get the position of the index in the array. */
167 int pos = _be_liveness_bsearch(irn_live, idx);
169 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
170 struct _be_lv_info_node_t *res = &irn_live[pos + 1].u.node;
172 /* Check, if the irn is in deed in the array. */
180 static struct _be_lv_info_node_t *be_lv_get_or_set(struct _be_lv_t *li, ir_node *bl, ir_node *irn)
182 struct _be_lv_info_t *irn_live = phase_get_or_set_irn_data(&li->ph, bl);
184 unsigned idx = get_irn_idx(irn);
186 /* Get the position of the index in the array. */
187 unsigned pos = _be_liveness_bsearch(irn_live, idx);
189 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
190 struct _be_lv_info_node_t *res = &irn_live[pos + 1].u.node;
192 /* Check, if the irn is in deed in the array. */
193 if(res->idx != idx) {
194 struct _be_lv_info_t *payload;
195 unsigned n_members = irn_live[0].u.head.n_members;
196 unsigned n_size = irn_live[0].u.head.n_size;
199 if(n_members == n_size - 1) {
200 unsigned new_size = 2 * n_size * sizeof(irn_live[0]);
201 struct _be_lv_info_t *nw = phase_alloc(&li->ph, new_size);
202 memcpy(nw, irn_live, new_size);
203 nw[0].u.head.n_size = new_size;
205 phase_set_irn_data(&li->ph, irn, nw);
208 payload = &irn_live[1];
209 for(i = n_members; i > pos; --i) {
210 payload[i] = payload[i - 1];
213 ++irn_live[0].u.head.n_members;
215 res = &payload[pos].u.node;
220 #ifdef LV_INTESIVE_CHECKS
223 unsigned n = irn_live[0].u.head.n_members;
225 struct _be_lv_info_t *payload = &irn_live[1];
227 for(i = 0; i < n; ++i) {
228 assert(payload[i].u.node.idx >= last);
229 last = payload[i].u.node.idx;
238 * Removes a node from the list of live variables of a block.
239 * @return 1 if the node was live at that block, 0 if not.
241 static int be_lv_remove(struct _be_lv_t *li, ir_node *bl, ir_node *irn)
243 struct _be_lv_info_t *irn_live = phase_get_irn_data(&li->ph, bl);
246 unsigned n = irn_live[0].u.head.n_members;
247 unsigned idx = get_irn_idx(irn);
248 unsigned pos = _be_liveness_bsearch(irn_live, idx);
249 struct _be_lv_info_t *payload = irn_live + 1;
250 struct _be_lv_info_node_t *res = &payload[pos].u.node;
252 /* The node is in deed in the block's array. Let's remove it. */
253 if(res->idx == idx) {
256 for(i = pos + 1; i < n; ++i)
257 payload[i - 1] = payload[i];
259 payload[n - 1].u.node.idx = 0;
260 payload[n - 1].u.node.flags = 0;
262 --irn_live[0].u.head.n_members;
263 DBG((dbg, LEVEL_3, "\tdeleting %+F from %+F at pos %d\n", irn, bl, pos));
271 static void register_node(be_lv_t *lv, const ir_node *irn)
273 unsigned idx = get_irn_idx(irn);
274 if(idx >= bitset_size(lv->nodes)) {
275 bitset_t *nw = bitset_malloc(2 * idx);
276 bitset_copy(nw, lv->nodes);
277 bitset_free(lv->nodes);
281 bitset_set(lv->nodes, idx);
285 * Mark a node as live-in in a block.
287 static INLINE void mark_live_in(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((dbg, LEVEL_2, "marking %+F live in at %+F\n", irn, block));
291 n->flags |= be_lv_state_in;
292 register_node(lv, irn);
296 * Mark a node as live-out in a block.
298 static INLINE void mark_live_out(be_lv_t *lv, ir_node *block, ir_node *irn)
300 struct _be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
301 DBG((dbg, LEVEL_2, "marking %+F live out at %+F\n", irn, block));
302 n->flags |= be_lv_state_out | be_lv_state_end;
303 register_node(lv, irn);
307 * Mark a node as live-end in a block.
309 static INLINE void mark_live_end(be_lv_t *lv, ir_node *block, ir_node *irn)
311 struct _be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
312 DBG((dbg, LEVEL_2, "marking %+F live end at %+F\n", irn, block));
313 n->flags |= be_lv_state_end;
314 register_node(lv, irn);
318 * Mark a node (value) live out at a certain block. Do this also
319 * transitively, i.e. if the block is not the block of the value's
320 * definition, all predecessors are also marked live.
321 * @param def The node (value).
322 * @param block The block to mark the value live out of.
323 * @param visited A set were all visited blocks are recorded.
324 * @param is_true_out Is the node real out there or only live at the end
327 static void live_end_at_block(be_lv_t *lv, ir_node *def, ir_node *block, bitset_t *visited, int is_true_out)
329 mark_live_end(lv, block, def);
331 mark_live_out(lv, block, def);
333 if(!bitset_contains_irn(visited, block)) {
334 bitset_add_irn(visited, block);
337 * If this block is not the definition block, we have to go up
340 if(get_nodes_block(def) != block) {
343 mark_live_in(lv, block, def);
345 for(i = 0, n = get_Block_n_cfgpreds(block); i < n; ++i)
346 live_end_at_block(lv, def, get_Block_cfgpred_block(block, i), visited, 1);
352 struct _lv_walker_t {
358 * Liveness analysis for a value.
359 * This functions is meant to be called by a firm walker, to compute the
360 * set of all blocks a value is live in.
361 * @param irn The node (value).
362 * @param env Ignored.
364 static void liveness_for_node(ir_node *irn, void *data)
366 struct _lv_walker_t *walker = data;
367 be_lv_t *lv = walker->lv;
368 bitset_t *visited = walker->data;
369 const ir_edge_t *edge;
372 /* Don't compute liveness information for non-data nodes. */
373 if(!is_liveness_node(irn))
376 bitset_clear_all(visited);
377 def_block = get_nodes_block(irn);
379 /* Go over all uses of the value */
380 foreach_out_edge(irn, edge) {
381 ir_node *use = edge->src;
385 * If the usage is no data node, skip this use, since it does not
386 * affect the liveness of the node.
388 if(!is_liveness_node(use))
391 /* Get the block where the usage is in. */
392 use_block = get_nodes_block(use);
395 * If the use is a phi function, determine the corresponding block
396 * through which the value reaches the phi function and mark the
397 * value as live out of that block.
400 ir_node *pred_block = get_Block_cfgpred_block(use_block, edge->pos);
401 live_end_at_block(lv, irn, pred_block, visited, 0);
405 * Else, the value is live in at this block. Mark it and call live
406 * out on the predecessors.
408 else if(def_block != use_block) {
411 mark_live_in(lv, use_block, irn);
413 for(i = 0, n = get_Block_n_cfgpreds(use_block); i < n; ++i) {
414 ir_node *pred_block = get_Block_cfgpred_block(use_block, i);
415 live_end_at_block(lv, irn, pred_block, visited, 1);
421 static void lv_remove_irn_walker(ir_node *bl, void *data)
423 struct _lv_walker_t *w = data;
425 ir_node *irn = w->data;
426 be_lv_remove(lv, bl, irn);
429 static const char *lv_flags_to_str(unsigned flags)
431 static const char *states[] = {
442 return states[flags & 7];
445 static void lv_dump_block(void *context, FILE *f, const ir_node *bl)
448 be_lv_t *lv = context;
449 struct _be_lv_info_t *info = phase_get_irn_data(&lv->ph, bl);
451 fprintf(f, "liveness:\n");
453 unsigned n = info[0].u.head.n_members;
456 for(i = 0; i < n; ++i) {
457 struct _be_lv_info_node_t *n = &info[i+1].u.node;
458 ir_fprintf(f, "%s %+F\n", lv_flags_to_str(n->flags), get_idx_irn(lv->irg, n->idx));
464 static void *lv_phase_data_init(ir_phase *phase, ir_node *irn, void *old)
466 struct _be_lv_info_t *info = phase_alloc(phase, LV_STD_SIZE * sizeof(info[0]));
467 memset(info, 0, LV_STD_SIZE * sizeof(info[0]));
468 info[0].u.head.n_size = LV_STD_SIZE - 1;
472 static void compute_liveness(be_lv_t *lv)
474 struct _lv_walker_t w;
476 w.data = bitset_malloc(get_irg_last_idx(lv->irg));
477 irg_walk_graph(lv->irg, liveness_for_node, NULL, &w);
481 /* Compute the inter block liveness for a graph. */
482 be_lv_t *be_liveness(ir_graph *irg)
484 be_lv_t *lv = xmalloc(sizeof(lv[0]));
486 memset(lv, 0, sizeof(lv[0]));
488 lv->nodes = bitset_malloc(2 * get_irg_last_idx(irg));
489 lv->hook_info.context = lv;
490 lv->hook_info.hook._hook_node_info = lv_dump_block;
491 register_hook(hook_node_info, &lv->hook_info);
492 phase_init(&lv->ph, "liveness", irg, PHASE_DEFAULT_GROWTH, lv_phase_data_init, NULL);
493 compute_liveness(lv);
498 void be_liveness_recompute(be_lv_t *lv)
500 unsigned last_idx = get_irg_last_idx(lv->irg);
501 if(last_idx >= bitset_size(lv->nodes)) {
502 bitset_free(lv->nodes);
503 lv->nodes = bitset_malloc(last_idx * 2);
507 bitset_clear_all(lv->nodes);
510 phase_init(&lv->ph, "liveness", lv->irg, PHASE_DEFAULT_GROWTH, lv_phase_data_init, NULL);
511 compute_liveness(lv);
515 void be_liveness_free(be_lv_t *lv)
517 unregister_hook(hook_node_info, &lv->hook_info);
519 bitset_free(lv->nodes);
523 void be_liveness_remove(be_lv_t *lv, ir_node *irn)
525 unsigned idx = get_irn_idx(irn);
526 struct _lv_walker_t w;
529 * Removes a single irn from the liveness information.
530 * Since an irn can only be live at blocks dominated by the block of its
531 * definition, we only have to process that dominance subtree.
535 dom_tree_walk(get_nodes_block(irn), lv_remove_irn_walker, NULL, &w);
536 if(idx < bitset_size(lv->nodes))
537 bitset_clear(lv->nodes, idx);
540 void be_liveness_introduce(be_lv_t *lv, ir_node *irn)
542 struct _lv_walker_t w;
544 w.data = bitset_malloc(get_irg_last_idx(lv->irg));
545 liveness_for_node(irn, &w);
549 void be_liveness_update(be_lv_t *lv, ir_node *irn)
551 be_liveness_remove(lv, irn);
552 be_liveness_introduce(lv, irn);
555 static void lv_add_missing_walker(ir_node *irn, void *data)
557 struct _lv_walker_t *w = data;
558 if(!is_Block(irn) && !bitset_contains_irn(w->lv->nodes, irn)) {
559 liveness_for_node(irn, w);
563 void be_liveness_add_missing(be_lv_t *lv)
565 struct _lv_walker_t w;
567 w.data = bitset_malloc(get_irg_last_idx(lv->irg));
568 irg_walk_graph(lv->irg, lv_add_missing_walker, NULL, &w);
572 static void lv_check_walker(ir_node *bl, void *data)
574 struct _lv_walker_t *w = data;
576 be_lv_t *fresh = w->data;
578 struct _be_lv_info_t *curr = phase_get_irn_data(&lv->ph, bl);
579 struct _be_lv_info_t *fr = phase_get_irn_data(&fresh->ph, bl);
581 if(!fr && curr && curr[0].u.head.n_members > 0) {
584 ir_fprintf(stderr, "%+F liveness should be empty but current liveness contains:\n", bl);
585 for(i = 0; i < curr[0].u.head.n_members; ++i) {
586 ir_fprintf(stderr, "\t%+F\n", get_idx_irn(lv->irg, curr[1 + i].u.node.idx));
591 unsigned n_curr = curr[0].u.head.n_members;
592 unsigned n_fresh = fr[0].u.head.n_members;
596 if(n_curr != n_fresh) {
597 ir_fprintf(stderr, "%+F: liveness set sizes differ. curr %d, correct %d\n", bl, n_curr, n_fresh);
599 ir_fprintf(stderr, "current:\n");
600 for(i = 0; i < n_curr; ++i) {
601 struct _be_lv_info_node_t *n = &curr[1 + i].u.node;
602 ir_fprintf(stderr, "%+F %u %+F %s\n", bl, i, get_idx_irn(lv->irg, n->idx), lv_flags_to_str(n->flags));
605 ir_fprintf(stderr, "correct:\n");
606 for(i = 0; i < n_fresh; ++i) {
607 struct _be_lv_info_node_t *n = &fr[1 + i].u.node;
608 ir_fprintf(stderr, "%+F %u %+F %s\n", bl, i, get_idx_irn(lv->irg, n->idx), lv_flags_to_str(n->flags));
614 void be_liveness_check(be_lv_t *lv)
616 struct _lv_walker_t w;
617 be_lv_t *fresh = be_liveness(lv->irg);
621 irg_block_walk_graph(lv->irg, lv_check_walker, NULL, &w);
622 be_liveness_free(fresh);
626 static void lv_dump_block_walker(ir_node *irn, void *data)
628 struct _lv_walker_t *w = data;
630 lv_dump_block(w->lv, w->data, irn);
634 /* Dump the liveness information for a graph. */
635 void be_liveness_dump(const be_lv_t *lv, FILE *f)
637 struct _lv_walker_t w;
639 w.lv = (be_lv_t *) lv;
641 irg_block_walk_graph(lv->irg, lv_dump_block_walker, NULL, &w);
644 /* Dump the liveness information for a graph. */
645 void be_liveness_dumpto(const be_lv_t *lv, const char *cls_name)
649 ir_snprintf(buf, sizeof(buf), "%F_%s-live.txt", lv->irg, cls_name);
650 if((f = fopen(buf, "wt")) != NULL) {
651 be_liveness_dump(lv, f);
657 * Walker: checks the every predecessors of a node dominate
660 static void dom_check(ir_node *irn, void *data)
662 int *problem_found = data;
664 if(!is_Block(irn) && irn != get_irg_end(get_irn_irg(irn))) {
666 ir_node *bl = get_nodes_block(irn);
668 for(i = 0, n = get_irn_arity(irn); i < n; ++i) {
669 ir_node *op = get_irn_n(irn, i);
670 ir_node *def_bl = get_nodes_block(op);
671 ir_node *use_bl = bl;
674 use_bl = get_Block_cfgpred_block(bl, i);
676 if(get_irn_opcode(use_bl) != iro_Bad
677 && get_irn_opcode(def_bl) != iro_Bad
678 && !block_dominates(def_bl, use_bl)) {
679 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)));
686 /* Check, if the SSA dominance property is fulfilled. */
687 int be_check_dominance(ir_graph *irg)
689 int problem_found = 0;
692 irg_walk_graph(irg, dom_check, NULL, &problem_found);
694 return !problem_found;
697 pset *be_liveness_transfer(const arch_env_t *arch_env, const arch_register_class_t *cls, ir_node *irn, pset *live)
701 /* You should better break out of your loop when hitting the first phi function. */
702 assert(!is_Phi(irn) && "liveness_transfer produces invalid results for phi nodes");
704 if(arch_irn_consider_in_reg_alloc(arch_env, cls, irn)) {
705 ir_node *del = pset_remove_ptr(live, irn);
710 for(i = 0, n = get_irn_arity(irn); i < n; ++i) {
711 ir_node *op = get_irn_n(irn, i);
713 if(arch_irn_consider_in_reg_alloc(arch_env, cls, op))
714 pset_insert_ptr(live, op);
720 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)
723 be_lv_foreach(lv, bl, be_lv_state_end, i) {
724 ir_node *irn = be_lv_get_irn(lv, bl, i);
725 if(arch_irn_consider_in_reg_alloc(arch_env, cls, irn))
726 pset_insert_ptr(live, irn);
732 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)
734 const ir_node *bl = is_Block(pos) ? pos : get_nodes_block(pos);
737 be_liveness_end_of_block(lv, arch_env, cls, bl, live);
738 sched_foreach_reverse(bl, irn) {
740 * If we encounter the node we want to insert the Perm after,
741 * exit immediately, so that this node is still live
746 be_liveness_transfer(arch_env, cls, irn, live);
752 pset *be_liveness_nodes_live_at_input(const be_lv_t *lv, const arch_env_t *arch_env, const arch_register_class_t *cls, const ir_node *pos, pset *live)
754 const ir_node *bl = is_Block(pos) ? pos : get_nodes_block(pos);
757 be_liveness_end_of_block(lv, arch_env, cls, bl, live);
758 sched_foreach_reverse(bl, irn) {
759 be_liveness_transfer(arch_env, cls, irn, live);
767 void be_init_live(void)
769 FIRM_DBG_REGISTER(dbg, "firm.be.liveness");
772 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_live);