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
21 * Interblock liveness analysis.
22 * @author Sebastian Hack
30 #include "iredges_t.h"
32 #include "irprintf_t.h"
38 #include "besched_t.h"
41 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
43 #define LV_STD_SIZE 128
44 #define LV_USE_BINARY_SEARCH
45 #undef LV_INTESIVE_CHECKS
47 static INLINE int is_liveness_node(const ir_node *irn)
49 switch(get_irn_opcode(irn)) {
60 int (be_lv_next_irn)(const struct _be_lv_t *lv, const ir_node *bl, unsigned flags, int i)
62 return _be_lv_next_irn(lv, bl, flags, i);
65 const ir_node * (be_lv_get_irn)(const struct _be_lv_t *lv, const ir_node *bl, int i)
67 return _be_lv_get_irn(lv, bl, i);
70 int (be_is_live_in)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
72 return _be_is_live_xxx(lv, block, irn, be_lv_state_in);
75 int (be_is_live_out)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
77 return _be_is_live_xxx(lv, block, irn, be_lv_state_out);
80 int (be_is_live_end)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
82 return _be_is_live_xxx(lv, block, irn, be_lv_state_end);
86 #ifdef LV_USE_BINARY_SEARCH
87 static INLINE unsigned _be_liveness_bsearch(struct _be_lv_info_t *arr, unsigned idx)
89 struct _be_lv_info_t *payload = arr + 1;
91 unsigned n = arr[0].u.head.n_members;
100 if(idx < payload[0].u.node.idx)
103 if(idx > payload[n - 1].u.node.idx)
107 /* start a binary search for the requested node. */
109 int md = lo + ((hi - lo) >> 1);
110 unsigned md_idx = payload[md].u.node.idx;
114 else if(idx < md_idx)
118 assert(payload[res].u.node.idx == idx);
125 #ifdef LV_INTESIVE_CHECKS
128 for(i = res; i < n; ++i)
129 assert(payload[i].u.node.idx >= idx);
131 for(i = 0; i < res; ++i)
132 assert(payload[i].u.node.idx < idx);
142 * This function searches linearly for the node in the array.
144 static INLINE unsigned _be_liveness_bsearch(struct _be_lv_info_t *arr, unsigned idx) {
145 unsigned n = arr[0].u.head.n_members;
148 for(i = 0; i < n; ++i) {
149 if(arr[i + 1].u.node.idx == idx)
157 struct _be_lv_info_node_t *be_lv_get(const struct _be_lv_t *li, const ir_node *bl, const ir_node *irn)
159 struct _be_lv_info_t *irn_live = phase_get_irn_data(&li->ph, bl);
162 unsigned idx = get_irn_idx(irn);
164 /* Get the position of the index in the array. */
165 int 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. */
178 static struct _be_lv_info_node_t *be_lv_get_or_set(struct _be_lv_t *li, ir_node *bl, ir_node *irn)
180 struct _be_lv_info_t *irn_live = phase_get_or_set_irn_data(&li->ph, bl);
182 unsigned idx = get_irn_idx(irn);
184 /* Get the position of the index in the array. */
185 unsigned pos = _be_liveness_bsearch(irn_live, idx);
187 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
188 struct _be_lv_info_node_t *res = &irn_live[pos + 1].u.node;
190 /* Check, if the irn is in deed in the array. */
191 if(res->idx != idx) {
192 struct _be_lv_info_t *payload;
193 unsigned n_members = irn_live[0].u.head.n_members;
194 unsigned n_size = irn_live[0].u.head.n_size;
197 if(n_members == n_size - 1) {
198 unsigned new_size = 2 * n_size * sizeof(irn_live[0]);
199 struct _be_lv_info_t *nw = phase_alloc(&li->ph, new_size);
200 memcpy(nw, irn_live, new_size);
201 nw[0].u.head.n_size = new_size;
203 phase_set_irn_data(&li->ph, irn, nw);
206 payload = &irn_live[1];
207 for(i = n_members; i > pos; --i) {
208 payload[i] = payload[i - 1];
211 ++irn_live[0].u.head.n_members;
213 res = &payload[pos].u.node;
218 #ifdef LV_INTESIVE_CHECKS
221 unsigned n = irn_live[0].u.head.n_members;
223 struct _be_lv_info_t *payload = &irn_live[1];
225 for(i = 0; i < n; ++i) {
226 assert(payload[i].u.node.idx >= last);
227 last = payload[i].u.node.idx;
236 * Removes a node from the list of live variables of a block.
237 * @return 1 if the node was live at that block, 0 if not.
239 static int be_lv_remove(struct _be_lv_t *li, ir_node *bl, ir_node *irn)
241 struct _be_lv_info_t *irn_live = phase_get_irn_data(&li->ph, bl);
244 unsigned n = irn_live[0].u.head.n_members;
245 unsigned idx = get_irn_idx(irn);
246 unsigned pos = _be_liveness_bsearch(irn_live, idx);
247 struct _be_lv_info_t *payload = irn_live + 1;
248 struct _be_lv_info_node_t *res = &payload[pos].u.node;
250 /* The node is in deed in the block's array. Let's remove it. */
251 if(res->idx == idx) {
254 for(i = pos + 1; i < n; ++i)
255 payload[i - 1] = payload[i];
257 payload[n - 1].u.node.idx = 0;
258 payload[n - 1].u.node.flags = 0;
260 --irn_live[0].u.head.n_members;
261 DBG((dbg, LEVEL_3, "\tdeleting %+F from %+F at pos %d\n", irn, bl, pos));
269 static void register_node(be_lv_t *lv, const ir_node *irn)
271 unsigned idx = get_irn_idx(irn);
272 if(idx >= bitset_size(lv->nodes)) {
273 bitset_t *nw = bitset_malloc(2 * idx);
274 bitset_copy(nw, lv->nodes);
275 bitset_free(lv->nodes);
279 bitset_set(lv->nodes, idx);
283 * Mark a node as live-in in a block.
285 static INLINE void mark_live_in(be_lv_t *lv, ir_node *block, ir_node *irn)
287 struct _be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
288 DBG((dbg, LEVEL_2, "marking %+F live in at %+F\n", irn, block));
289 n->flags |= be_lv_state_in;
290 register_node(lv, irn);
294 * Mark a node as live-out in a block.
296 static INLINE void mark_live_out(be_lv_t *lv, ir_node *block, ir_node *irn)
298 struct _be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
299 DBG((dbg, LEVEL_2, "marking %+F live out at %+F\n", irn, block));
300 n->flags |= be_lv_state_out | be_lv_state_end;
301 register_node(lv, irn);
305 * Mark a node as live-end in a block.
307 static INLINE void mark_live_end(be_lv_t *lv, ir_node *block, ir_node *irn)
309 struct _be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
310 DBG((dbg, LEVEL_2, "marking %+F live end at %+F\n", irn, block));
311 n->flags |= be_lv_state_end;
312 register_node(lv, irn);
316 * Mark a node (value) live out at a certain block. Do this also
317 * transitively, i.e. if the block is not the block of the value's
318 * definition, all predecessors are also marked live.
319 * @param def The node (value).
320 * @param block The block to mark the value live out of.
321 * @param visited A set were all visited blocks are recorded.
322 * @param is_true_out Is the node real out there or only live at the end
325 static void live_end_at_block(be_lv_t *lv, ir_node *def, ir_node *block, bitset_t *visited, int is_true_out)
327 mark_live_end(lv, block, def);
329 mark_live_out(lv, block, def);
331 if(!bitset_contains_irn(visited, block)) {
332 bitset_add_irn(visited, block);
335 * If this block is not the definition block, we have to go up
338 if(get_nodes_block(def) != block) {
341 mark_live_in(lv, block, def);
343 for(i = 0, n = get_Block_n_cfgpreds(block); i < n; ++i)
344 live_end_at_block(lv, def, get_Block_cfgpred_block(block, i), visited, 1);
350 struct _lv_walker_t {
356 * Liveness analysis for a value.
357 * This functions is meant to be called by a firm walker, to compute the
358 * set of all blocks a value is live in.
359 * @param irn The node (value).
360 * @param env Ignored.
362 static void liveness_for_node(ir_node *irn, void *data)
364 struct _lv_walker_t *walker = data;
365 be_lv_t *lv = walker->lv;
366 bitset_t *visited = walker->data;
367 const ir_edge_t *edge;
370 /* Don't compute liveness information for non-data nodes. */
371 if(!is_liveness_node(irn))
374 bitset_clear_all(visited);
375 def_block = get_nodes_block(irn);
377 /* Go over all uses of the value */
378 foreach_out_edge(irn, edge) {
379 ir_node *use = edge->src;
383 * If the usage is no data node, skip this use, since it does not
384 * affect the liveness of the node.
386 if(!is_liveness_node(use))
389 /* Get the block where the usage is in. */
390 use_block = get_nodes_block(use);
393 * If the use is a phi function, determine the corresponding block
394 * through which the value reaches the phi function and mark the
395 * value as live out of that block.
398 ir_node *pred_block = get_Block_cfgpred_block(use_block, edge->pos);
399 live_end_at_block(lv, irn, pred_block, visited, 0);
403 * Else, the value is live in at this block. Mark it and call live
404 * out on the predecessors.
406 else if(def_block != use_block) {
409 mark_live_in(lv, use_block, irn);
411 for(i = 0, n = get_Block_n_cfgpreds(use_block); i < n; ++i) {
412 ir_node *pred_block = get_Block_cfgpred_block(use_block, i);
413 live_end_at_block(lv, irn, pred_block, visited, 1);
419 static void lv_remove_irn_walker(ir_node *bl, void *data)
421 struct _lv_walker_t *w = data;
423 ir_node *irn = w->data;
424 be_lv_remove(lv, bl, irn);
427 static const char *lv_flags_to_str(unsigned flags)
429 static const char *states[] = {
440 return states[flags & 7];
443 static void lv_dump_block(void *context, FILE *f, const ir_node *bl)
446 be_lv_t *lv = context;
447 struct _be_lv_info_t *info = phase_get_irn_data(&lv->ph, bl);
449 fprintf(f, "liveness:\n");
451 unsigned n = info[0].u.head.n_members;
454 for(i = 0; i < n; ++i) {
455 struct _be_lv_info_node_t *n = &info[i+1].u.node;
456 ir_fprintf(f, "%s %+F\n", lv_flags_to_str(n->flags), get_idx_irn(lv->irg, n->idx));
462 static void *lv_phase_data_init(ir_phase *phase, ir_node *irn, void *old)
464 struct _be_lv_info_t *info = phase_alloc(phase, LV_STD_SIZE * sizeof(info[0]));
465 memset(info, 0, LV_STD_SIZE * sizeof(info[0]));
466 info[0].u.head.n_size = LV_STD_SIZE - 1;
470 static void compute_liveness(be_lv_t *lv)
472 struct _lv_walker_t w;
474 w.data = bitset_malloc(get_irg_last_idx(lv->irg));
475 irg_walk_graph(lv->irg, liveness_for_node, NULL, &w);
479 /* Compute the inter block liveness for a graph. */
480 be_lv_t *be_liveness(ir_graph *irg)
482 be_lv_t *lv = xmalloc(sizeof(lv[0]));
484 memset(lv, 0, sizeof(lv[0]));
486 lv->nodes = bitset_malloc(2 * get_irg_last_idx(irg));
487 lv->hook_info.context = lv;
488 lv->hook_info.hook._hook_node_info = lv_dump_block;
489 register_hook(hook_node_info, &lv->hook_info);
490 phase_init(&lv->ph, "liveness", irg, PHASE_DEFAULT_GROWTH, lv_phase_data_init, NULL);
491 compute_liveness(lv);
496 void be_liveness_recompute(be_lv_t *lv)
498 unsigned last_idx = get_irg_last_idx(lv->irg);
499 if(last_idx >= bitset_size(lv->nodes)) {
500 bitset_free(lv->nodes);
501 lv->nodes = bitset_malloc(last_idx * 2);
505 bitset_clear_all(lv->nodes);
508 phase_init(&lv->ph, "liveness", lv->irg, PHASE_DEFAULT_GROWTH, lv_phase_data_init, NULL);
509 compute_liveness(lv);
513 void be_liveness_free(be_lv_t *lv)
515 unregister_hook(hook_node_info, &lv->hook_info);
517 bitset_free(lv->nodes);
521 void be_liveness_remove(be_lv_t *lv, ir_node *irn)
523 unsigned idx = get_irn_idx(irn);
524 struct _lv_walker_t w;
527 * Removes a single irn from the liveness information.
528 * Since an irn can only be live at blocks dominated by the block of its
529 * definition, we only have to process that dominance subtree.
533 dom_tree_walk(get_nodes_block(irn), lv_remove_irn_walker, NULL, &w);
534 if(idx <= bitset_size(lv->nodes))
535 bitset_clear(lv->nodes, idx);
538 void be_liveness_introduce(be_lv_t *lv, ir_node *irn)
540 struct _lv_walker_t w;
542 w.data = bitset_malloc(get_irg_last_idx(lv->irg));
543 liveness_for_node(irn, &w);
547 void be_liveness_update(be_lv_t *lv, ir_node *irn)
549 be_liveness_remove(lv, irn);
550 be_liveness_introduce(lv, irn);
553 static void lv_add_missing_walker(ir_node *irn, void *data)
555 struct _lv_walker_t *w = data;
556 if(!is_Block(irn) && !bitset_contains_irn(w->lv->nodes, irn)) {
557 liveness_for_node(irn, w);
561 void be_liveness_add_missing(be_lv_t *lv)
563 struct _lv_walker_t w;
565 w.data = bitset_malloc(get_irg_last_idx(lv->irg));
566 irg_walk_graph(lv->irg, lv_add_missing_walker, NULL, &w);
570 static void lv_check_walker(ir_node *bl, void *data)
572 struct _lv_walker_t *w = data;
574 be_lv_t *fresh = w->data;
576 struct _be_lv_info_t *curr = phase_get_irn_data(&lv->ph, bl);
577 struct _be_lv_info_t *fr = phase_get_irn_data(&fresh->ph, bl);
579 if(!fr && curr && curr[0].u.head.n_members > 0) {
582 ir_fprintf(stderr, "%+F liveness should be empty but current liveness contains:\n", bl);
583 for(i = 0; i < curr[0].u.head.n_members; ++i) {
584 ir_fprintf(stderr, "\t%+F\n", get_idx_irn(lv->irg, curr[1 + i].u.node.idx));
589 unsigned n_curr = curr[0].u.head.n_members;
590 unsigned n_fresh = fr[0].u.head.n_members;
594 if(n_curr != n_fresh) {
595 ir_fprintf(stderr, "%+F: liveness set sizes differ. curr %d, correct %d\n", bl, n_curr, n_fresh);
597 ir_fprintf(stderr, "current:\n");
598 for(i = 0; i < n_curr; ++i) {
599 struct _be_lv_info_node_t *n = &curr[1 + i].u.node;
600 ir_fprintf(stderr, "%+F %u %+F %s\n", bl, i, get_idx_irn(lv->irg, n->idx), lv_flags_to_str(n->flags));
603 ir_fprintf(stderr, "correct:\n");
604 for(i = 0; i < n_fresh; ++i) {
605 struct _be_lv_info_node_t *n = &fr[1 + i].u.node;
606 ir_fprintf(stderr, "%+F %u %+F %s\n", bl, i, get_idx_irn(lv->irg, n->idx), lv_flags_to_str(n->flags));
612 void be_liveness_check(be_lv_t *lv)
614 struct _lv_walker_t w;
615 be_lv_t *fresh = be_liveness(lv->irg);
619 irg_block_walk_graph(lv->irg, lv_check_walker, NULL, &w);
620 be_liveness_free(fresh);
624 static void lv_dump_block_walker(ir_node *irn, void *data)
626 struct _lv_walker_t *w = data;
628 lv_dump_block(w->lv, w->data, irn);
632 /* Dump the liveness information for a graph. */
633 void be_liveness_dump(const be_lv_t *lv, FILE *f)
635 struct _lv_walker_t w;
637 w.lv = (be_lv_t *) lv;
639 irg_block_walk_graph(lv->irg, lv_dump_block_walker, NULL, &w);
642 /* Dump the liveness information for a graph. */
643 void be_liveness_dumpto(const be_lv_t *lv, const char *cls_name)
647 ir_snprintf(buf, sizeof(buf), "%F_%s-live.txt", lv->irg, cls_name);
648 if((f = fopen(buf, "wt")) != NULL) {
649 be_liveness_dump(lv, f);
655 * Walker: checks the every predecessors of a node dominate
658 static void dom_check(ir_node *irn, void *data)
660 int *problem_found = data;
662 if(!is_Block(irn) && irn != get_irg_end(get_irn_irg(irn))) {
664 ir_node *bl = get_nodes_block(irn);
666 for(i = 0, n = get_irn_arity(irn); i < n; ++i) {
667 ir_node *op = get_irn_n(irn, i);
668 ir_node *def_bl = get_nodes_block(op);
669 ir_node *use_bl = bl;
672 use_bl = get_Block_cfgpred_block(bl, i);
674 if(get_irn_opcode(use_bl) != iro_Bad
675 && get_irn_opcode(def_bl) != iro_Bad
676 && !block_dominates(def_bl, use_bl)) {
677 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)));
684 /* Check, if the SSA dominance property is fulfilled. */
685 int be_check_dominance(ir_graph *irg)
687 int problem_found = 0;
690 irg_walk_graph(irg, dom_check, NULL, &problem_found);
692 return !problem_found;
695 pset *be_liveness_transfer(const arch_env_t *arch_env, const arch_register_class_t *cls, ir_node *irn, pset *live)
699 /* You should better break out of your loop when hitting the first phi function. */
700 assert(!is_Phi(irn) && "liveness_transfer produces invalid results for phi nodes");
702 if(arch_irn_consider_in_reg_alloc(arch_env, cls, irn)) {
703 ir_node *del = pset_remove_ptr(live, irn);
708 for(i = 0, n = get_irn_arity(irn); i < n; ++i) {
709 ir_node *op = get_irn_n(irn, i);
711 if(arch_irn_consider_in_reg_alloc(arch_env, cls, op))
712 pset_insert_ptr(live, op);
718 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)
721 be_lv_foreach(lv, bl, be_lv_state_end, i) {
722 ir_node *irn = be_lv_get_irn(lv, bl, i);
723 if(arch_irn_consider_in_reg_alloc(arch_env, cls, irn))
724 pset_insert_ptr(live, irn);
730 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)
732 const ir_node *bl = is_Block(pos) ? pos : get_nodes_block(pos);
735 be_liveness_end_of_block(lv, arch_env, cls, bl, live);
736 sched_foreach_reverse(bl, irn) {
738 * If we encounter the node we want to insert the Perm after,
739 * exit immediately, so that this node is still live
744 be_liveness_transfer(arch_env, cls, irn, live);
750 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)
752 const ir_node *bl = is_Block(pos) ? pos : get_nodes_block(pos);
755 be_liveness_end_of_block(lv, arch_env, cls, bl, live);
756 sched_foreach_reverse(bl, irn) {
757 be_liveness_transfer(arch_env, cls, irn, live);
765 void be_init_live(void)
767 FIRM_DBG_REGISTER(dbg, "firm.be.liveness");
770 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_live);