2 * Copyright (C) 1995-2008 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
29 /* statev is expensive here, only enable when needed */
30 #define DISABLE_STATEV
32 #include "iredges_t.h"
34 #include "irprintf_t.h"
37 #include "irnodeset.h"
49 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
51 #define LV_STD_SIZE 64
53 /* if defined, use binary search for already live nodes, else linear */
54 #define LV_USE_BINARY_SEARCH
55 #undef LV_INTESIVE_CHECKS
57 void be_live_chk_compare(be_lv_t *lv, lv_chk_t *lvc);
60 * Filter out some nodes for which we never need liveness.
62 * @param irn the node t check
63 * @return 0 if no liveness info is needed, 1 else
65 static inline int is_liveness_node(const ir_node *irn)
67 switch (get_irn_opcode(irn)) {
79 int (be_is_live_in)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
81 return _be_is_live_xxx(lv, block, irn, be_lv_state_in);
84 int (be_is_live_out)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
86 return _be_is_live_xxx(lv, block, irn, be_lv_state_out);
89 int (be_is_live_end)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
91 return _be_is_live_xxx(lv, block, irn, be_lv_state_end);
95 #ifdef LV_USE_BINARY_SEARCH
96 static inline unsigned _be_liveness_bsearch(be_lv_info_t *arr, unsigned idx)
98 be_lv_info_t *payload = arr + 1;
100 unsigned n = arr[0].head.n_members;
109 int md = lo + ((hi - lo) >> 1);
110 unsigned md_idx = payload[md].node.idx;
114 else if (idx < md_idx)
118 assert(payload[res].node.idx == idx);
125 #ifdef LV_INTESIVE_CHECKS
128 for (i = res; i < n; ++i)
129 assert(payload[i].node.idx >= idx);
131 for (i = 0; i < res; ++i)
132 assert(payload[i].node.idx < idx);
142 * This function searches linearly for the node in the array.
144 static inline unsigned _be_liveness_bsearch(be_lv_info_t *arr, unsigned idx)
146 unsigned n = arr[0].head.n_members;
149 for (i = 0; i < n; ++i) {
150 if (arr[i + 1].node.idx == idx)
158 be_lv_info_node_t *be_lv_get(const be_lv_t *li, const ir_node *bl,
161 be_lv_info_t *irn_live;
162 be_lv_info_node_t *res = NULL;
165 irn_live = (be_lv_info_t*)ir_nodehashmap_get(&li->map, bl);
166 if (irn_live != NULL) {
167 unsigned idx = get_irn_idx(irn);
169 /* Get the position of the index in the array. */
170 int pos = _be_liveness_bsearch(irn_live, idx);
172 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
173 be_lv_info_node_t *rec = &irn_live[pos + 1].node;
175 /* Check, if the irn is in deed in the array. */
179 stat_ev_tim_pop("be_lv_get");
184 static be_lv_info_node_t *be_lv_get_or_set(be_lv_t *li, ir_node *bl,
187 be_lv_info_t *irn_live = (be_lv_info_t*)ir_nodehashmap_get(&li->map, bl);
188 if (irn_live == NULL) {
189 irn_live = OALLOCNZ(&li->obst, be_lv_info_t, LV_STD_SIZE);
190 irn_live[0].head.n_size = LV_STD_SIZE-1;
191 ir_nodehashmap_insert(&li->map, bl, irn_live);
194 unsigned idx = get_irn_idx(irn);
196 /* Get the position of the index in the array. */
197 unsigned pos = _be_liveness_bsearch(irn_live, idx);
199 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
200 be_lv_info_node_t *res = &irn_live[pos + 1].node;
202 /* Check, if the irn is in deed in the array. */
203 if (res->idx != idx) {
204 be_lv_info_t *payload;
205 unsigned n_members = irn_live[0].head.n_members;
206 unsigned n_size = irn_live[0].head.n_size;
209 if (n_members + 1 >= n_size) {
210 /* double the array size. Remember that the first entry is
211 * metadata about the array and not a real array element */
212 unsigned old_size_bytes = (n_size + 1) * sizeof(irn_live[0]);
213 unsigned new_size = (2 * n_size) + 1;
214 size_t new_size_bytes = new_size * sizeof(irn_live[0]);
215 be_lv_info_t *nw = OALLOCN(&li->obst, be_lv_info_t, new_size);
216 memcpy(nw, irn_live, old_size_bytes);
217 memset(((char*) nw) + old_size_bytes, 0,
218 new_size_bytes - old_size_bytes);
219 nw[0].head.n_size = new_size - 1;
221 ir_nodehashmap_insert(&li->map, bl, nw);
224 payload = &irn_live[1];
225 for (i = n_members; i > pos; --i) {
226 payload[i] = payload[i - 1];
229 ++irn_live[0].head.n_members;
231 res = &payload[pos].node;
236 #ifdef LV_INTESIVE_CHECKS
239 unsigned n = irn_live[0].head.n_members;
241 be_lv_info_t *payload = &irn_live[1];
243 for (i = 0; i < n; ++i) {
244 assert(payload[i].node.idx >= last);
245 last = payload[i].node.idx;
254 * Removes a node from the list of live variables of a block.
255 * @return 1 if the node was live at that block, 0 if not.
257 static int be_lv_remove(be_lv_t *li, const ir_node *bl,
260 be_lv_info_t *irn_live = (be_lv_info_t*)ir_nodehashmap_get(&li->map, bl);
262 if (irn_live != NULL) {
263 unsigned n = irn_live[0].head.n_members;
264 unsigned idx = get_irn_idx(irn);
265 unsigned pos = _be_liveness_bsearch(irn_live, idx);
266 be_lv_info_t *payload = irn_live + 1;
267 be_lv_info_node_t *res = &payload[pos].node;
269 /* The node is in deed in the block's array. Let's remove it. */
270 if (res->idx == idx) {
273 for (i = pos + 1; i < n; ++i)
274 payload[i - 1] = payload[i];
276 payload[n - 1].node.idx = 0;
277 payload[n - 1].node.flags = 0;
279 --irn_live[0].head.n_members;
280 DBG((dbg, LEVEL_3, "\tdeleting %+F from %+F at pos %d\n", irn, bl, pos));
288 static void register_node(be_lv_t *lv, const ir_node *irn)
290 unsigned idx = get_irn_idx(irn);
291 if (idx >= bitset_size(lv->nodes)) {
292 bitset_t *nw = bitset_malloc(2 * idx);
293 bitset_copy_into(nw, lv->nodes);
294 bitset_free(lv->nodes);
298 bitset_set(lv->nodes, idx);
302 * Mark a node as live-in in a block.
304 static inline void mark_live_in(be_lv_t *lv, ir_node *block, ir_node *irn)
306 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
307 DBG((dbg, LEVEL_2, "marking %+F live in at %+F\n", irn, block));
308 n->flags |= be_lv_state_in;
309 register_node(lv, irn);
313 * Mark a node as live-out in a block.
315 static inline void mark_live_out(be_lv_t *lv, ir_node *block, ir_node *irn)
317 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
318 DBG((dbg, LEVEL_2, "marking %+F live out at %+F\n", irn, block));
319 n->flags |= be_lv_state_out | be_lv_state_end;
320 register_node(lv, irn);
324 * Mark a node as live-end in a block.
326 static inline void mark_live_end(be_lv_t *lv, ir_node *block, ir_node *irn)
328 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
329 DBG((dbg, LEVEL_2, "marking %+F live end at %+F\n", irn, block));
330 n->flags |= be_lv_state_end;
331 register_node(lv, irn);
335 be_lv_t *lv; /**< The liveness object. */
336 ir_node *def; /**< The node (value). */
337 ir_node *def_block; /**< The block of def. */
338 bitset_t *visited; /**< A set were all visited blocks are recorded. */
342 * Mark a node (value) live out at a certain block. Do this also
343 * transitively, i.e. if the block is not the block of the value's
344 * definition, all predecessors are also marked live.
345 * @param block The block to mark the value live out of.
346 * @param is_true_out Is the node real out there or only live at the end
349 static void live_end_at_block(ir_node *block, int is_true_out)
352 ir_node *def = re.def;
355 mark_live_end(lv, block, def);
357 mark_live_out(lv, block, def);
359 visited = re.visited;
360 if (!bitset_contains_irn(visited, block)) {
361 bitset_add_irn(visited, block);
364 * If this block is not the definition block, we have to go up
367 if (re.def_block != block) {
370 mark_live_in(lv, block, def);
372 for (i = get_Block_n_cfgpreds(block) - 1; i >= 0; --i)
373 live_end_at_block(get_Block_cfgpred_block(block, i), 1);
378 typedef struct lv_walker_t {
383 typedef struct lv_remove_walker_t {
386 } lv_remove_walker_t;
390 * Liveness analysis for a value.
391 * Compute the set of all blocks a value is live in.
392 * @param irn The node (value).
394 static void liveness_for_node(ir_node *irn)
396 const ir_edge_t *edge;
399 bitset_clear_all(re.visited);
400 def_block = get_nodes_block(irn);
403 re.def_block = def_block;
405 /* Go over all uses of the value */
406 foreach_out_edge(irn, edge) {
407 ir_node *use = edge->src;
410 DBG((dbg, LEVEL_4, "%+F: use at %+F, pos %d in %+F\n", irn, use, edge->pos, get_block(use)));
411 assert(get_irn_n(use, edge->pos) == irn);
414 * If the usage is no data node, skip this use, since it does not
415 * affect the liveness of the node.
417 if (!is_liveness_node(use))
420 /* Get the block where the usage is in. */
421 use_block = get_nodes_block(use);
424 * If the use is a phi function, determine the corresponding block
425 * through which the value reaches the phi function and mark the
426 * value as live out of that block.
429 ir_node *pred_block = get_Block_cfgpred_block(use_block, edge->pos);
430 live_end_at_block(pred_block, 0);
434 * Else, the value is live in at this block. Mark it and call live
435 * out on the predecessors.
437 else if (def_block != use_block) {
440 mark_live_in(re.lv, use_block, irn);
442 for (i = get_Block_n_cfgpreds(use_block) - 1; i >= 0; --i) {
443 ir_node *pred_block = get_Block_cfgpred_block(use_block, i);
444 live_end_at_block(pred_block, 1);
450 static void lv_remove_irn_walker(ir_node *bl, void *data)
452 lv_remove_walker_t *w = (lv_remove_walker_t*)data;
453 be_lv_remove(w->lv, bl, w->irn);
456 static const char *lv_flags_to_str(unsigned flags)
458 static const char *states[] = {
469 return states[flags & 7];
472 static void lv_dump_block(void *context, FILE *f, const ir_node *bl)
475 be_lv_t *lv = (be_lv_t*)context;
476 be_lv_info_t *info = (be_lv_info_t*)ir_nodehashmap_get(&lv->map, bl);
478 fprintf(f, "liveness:\n");
480 unsigned n = info[0].head.n_members;
483 for (i = 0; i < n; ++i) {
484 be_lv_info_node_t *n = &info[i+1].node;
485 ir_fprintf(f, "%s %+F\n", lv_flags_to_str(n->flags), get_idx_irn(lv->irg, n->idx));
492 * Walker, collect all nodes for which we want calculate liveness info
495 static void collect_liveness_nodes(ir_node *irn, void *data)
497 ir_node **nodes = (ir_node**)data;
498 if (is_liveness_node(irn))
499 nodes[get_irn_idx(irn)] = irn;
502 static void compute_liveness(be_lv_t *lv)
508 n = get_irg_last_idx(lv->irg);
509 nodes = NEW_ARR_F(ir_node *, n);
510 memset(nodes, 0, sizeof(nodes[0]) * n);
513 * inserting the variables sorted by their ID is probably
514 * more efficient since the binary sorted set insertion
515 * will not need to move around the data.
517 irg_walk_graph(lv->irg, NULL, collect_liveness_nodes, nodes);
520 re.visited = bitset_malloc(n);
522 for (i = 0; i < n; ++i) {
523 if (nodes[i] != NULL)
524 liveness_for_node(nodes[i]);
529 register_hook(hook_node_info, &lv->hook_info);
530 stat_ev_tim_pop("be_lv_sets_cons");
533 void be_liveness_assure_sets(be_lv_t *lv)
536 be_timer_push(T_LIVE);
538 lv->nodes = bitset_malloc(2 * get_irg_last_idx(lv->irg));
539 ir_nodehashmap_init(&lv->map);
540 obstack_init(&lv->obst);
541 compute_liveness(lv);
542 /* be_live_chk_compare(lv, lv->lvc); */
544 be_timer_pop(T_LIVE);
548 void be_liveness_assure_chk(be_lv_t *lv)
551 be_timer_push(t_verify);
552 be_liveness_assure_sets(lv);
553 be_timer_pop(t_verify);
559 void be_liveness_invalidate(be_lv_t *lv)
561 if (lv && lv->nodes) {
562 unregister_hook(hook_node_info, &lv->hook_info);
563 obstack_free(&lv->obst, NULL);
564 ir_nodehashmap_destroy(&lv->map);
565 bitset_free(lv->nodes);
570 /* Compute the inter block liveness for a graph. */
571 be_lv_t *be_liveness(ir_graph *irg)
573 be_lv_t *lv = XMALLOCZ(be_lv_t);
577 lv->dfs = dfs_new(&absgraph_irg_cfg_succ, irg);
578 lv->lvc = lv_chk_new(lv->irg, lv->dfs);
580 lv->hook_info.context = lv;
581 lv->hook_info.hook._hook_node_info = lv_dump_block;
586 void be_liveness_recompute(be_lv_t *lv)
590 be_timer_push(T_LIVE);
591 last_idx = get_irg_last_idx(lv->irg);
592 if (last_idx >= bitset_size(lv->nodes)) {
593 bitset_free(lv->nodes);
594 lv->nodes = bitset_malloc(last_idx * 2);
596 bitset_clear_all(lv->nodes);
598 ir_nodehashmap_destroy(&lv->map);
599 obstack_free(&lv->obst, NULL);
601 ir_nodehashmap_init(&lv->map);
602 obstack_init(&lv->obst);
603 compute_liveness(lv);
605 be_timer_pop(T_LIVE);
609 void be_liveness_free(be_lv_t *lv)
611 be_liveness_invalidate(lv);
613 lv_chk_free(lv->lvc);
619 void be_liveness_remove(be_lv_t *lv, const ir_node *irn)
622 unsigned idx = get_irn_idx(irn);
623 lv_remove_walker_t w;
626 * Removes a single irn from the liveness information.
627 * Since an irn can only be live at blocks dominated by the block of its
628 * definition, we only have to process that dominance subtree.
632 dom_tree_walk(get_nodes_block(irn), lv_remove_irn_walker, NULL, &w);
633 if (idx < bitset_size(lv->nodes))
634 bitset_clear(lv->nodes, idx);
638 void be_liveness_introduce(be_lv_t *lv, ir_node *irn)
640 /* Don't compute liveness information for non-data nodes. */
641 if (lv->nodes && is_liveness_node(irn)) {
643 re.visited = bitset_malloc(get_irg_last_idx(lv->irg));
644 liveness_for_node(irn);
645 bitset_free(re.visited);
649 void be_liveness_update(be_lv_t *lv, ir_node *irn)
651 be_liveness_remove(lv, irn);
652 be_liveness_introduce(lv, irn);
655 static void lv_check_walker(ir_node *bl, void *data)
657 lv_walker_t *w = (lv_walker_t*)data;
659 be_lv_t *fresh = (be_lv_t*)w->data;
661 be_lv_info_t *curr = (be_lv_info_t*)ir_nodehashmap_get(&fresh->map, bl);
662 be_lv_info_t *fr = (be_lv_info_t*)ir_nodehashmap_get(&fresh->map, bl);
664 if (!fr && curr && curr[0].head.n_members > 0) {
667 ir_fprintf(stderr, "%+F liveness should be empty but current liveness contains:\n", bl);
668 for (i = 0; i < curr[0].head.n_members; ++i) {
669 ir_fprintf(stderr, "\t%+F\n", get_idx_irn(lv->irg, curr[1 + i].node.idx));
674 unsigned n_curr = curr[0].head.n_members;
675 unsigned n_fresh = fr[0].head.n_members;
679 if (n_curr != n_fresh) {
680 ir_fprintf(stderr, "%+F: liveness set sizes differ. curr %d, correct %d\n", bl, n_curr, n_fresh);
682 ir_fprintf(stderr, "current:\n");
683 for (i = 0; i < n_curr; ++i) {
684 be_lv_info_node_t *n = &curr[1 + i].node;
685 ir_fprintf(stderr, "%+F %u %+F %s\n", bl, i, get_idx_irn(lv->irg, n->idx), lv_flags_to_str(n->flags));
688 ir_fprintf(stderr, "correct:\n");
689 for (i = 0; i < n_fresh; ++i) {
690 be_lv_info_node_t *n = &fr[1 + i].node;
691 ir_fprintf(stderr, "%+F %u %+F %s\n", bl, i, get_idx_irn(lv->irg, n->idx), lv_flags_to_str(n->flags));
697 void be_liveness_check(be_lv_t *lv)
700 be_lv_t *fresh = be_liveness(lv->irg);
704 irg_block_walk_graph(lv->irg, lv_check_walker, NULL, &w);
705 be_liveness_free(fresh);
709 static void lv_dump_block_walker(ir_node *irn, void *data)
711 lv_walker_t *w = (lv_walker_t*)data;
713 lv_dump_block(w->lv, (FILE*)w->data, irn);
717 /* Dump the liveness information for a graph. */
718 void be_liveness_dump(const be_lv_t *lv, FILE *f)
722 w.lv = (be_lv_t *) lv;
724 irg_block_walk_graph(lv->irg, lv_dump_block_walker, NULL, &w);
727 /* Dump the liveness information for a graph. */
728 void be_liveness_dumpto(const be_lv_t *lv, const char *cls_name)
732 ir_snprintf(buf, sizeof(buf), "%F_%s-live.txt", lv->irg, cls_name);
733 if ((f = fopen(buf, "wt")) != NULL) {
734 be_liveness_dump(lv, f);
740 * Walker: checks that every predecessors of a node dominates the node.
742 static void dom_check(ir_node *irn, void *data)
744 int *problem_found = (int*)data;
746 if (!is_Block(irn) && irn != get_irg_end(get_irn_irg(irn))) {
748 ir_node *bl = get_nodes_block(irn);
750 for (i = 0, n = get_irn_arity(irn); i < n; ++i) {
751 ir_node *op = get_irn_n(irn, i);
752 ir_node *def_bl = get_nodes_block(op);
753 ir_node *use_bl = bl;
756 use_bl = get_Block_cfgpred_block(bl, i);
758 if (get_irn_opcode(use_bl) != iro_Bad
759 && get_irn_opcode(def_bl) != iro_Bad
760 && !block_dominates(def_bl, use_bl)) {
761 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)));
768 /* Check, if the SSA dominance property is fulfilled. */
769 int be_check_dominance(ir_graph *irg)
771 int problem_found = 0;
774 irg_walk_graph(irg, dom_check, NULL, &problem_found);
776 return !problem_found;
779 void be_liveness_transfer(const arch_register_class_t *cls,
780 ir_node *node, ir_nodeset_t *nodeset)
784 /* You should better break out of your loop when hitting the first phi
786 assert(!is_Phi(node) && "liveness_transfer produces invalid results for phi nodes");
788 if (get_irn_mode(node) == mode_T) {
789 const ir_edge_t *edge;
791 foreach_out_edge(node, edge) {
792 ir_node *proj = get_edge_src_irn(edge);
794 if (arch_irn_consider_in_reg_alloc(cls, proj)) {
795 ir_nodeset_remove(nodeset, proj);
798 } else if (arch_irn_consider_in_reg_alloc(cls, node)) {
799 ir_nodeset_remove(nodeset, node);
802 arity = get_irn_arity(node);
803 for (i = 0; i < arity; ++i) {
804 ir_node *op = get_irn_n(node, i);
806 if (arch_irn_consider_in_reg_alloc(cls, op))
807 ir_nodeset_insert(nodeset, op);
813 void be_liveness_end_of_block(const be_lv_t *lv,
814 const arch_register_class_t *cls,
815 const ir_node *block, ir_nodeset_t *live)
819 assert(lv->nodes && "live sets must be computed");
820 be_lv_foreach(lv, block, be_lv_state_end, i) {
821 ir_node *node = be_lv_get_irn(lv, block, i);
822 if (!arch_irn_consider_in_reg_alloc(cls, node))
825 ir_nodeset_insert(live, node);
831 void be_liveness_nodes_live_at(const be_lv_t *lv,
832 const arch_register_class_t *cls,
833 const ir_node *pos, ir_nodeset_t *live)
835 const ir_node *bl = is_Block(pos) ? pos : get_nodes_block(pos);
838 be_liveness_end_of_block(lv, cls, bl, live);
839 sched_foreach_reverse(bl, irn) {
841 * If we encounter the node we want to insert the Perm after,
842 * exit immediately, so that this node is still live
847 be_liveness_transfer(cls, irn, live);
851 static void collect_node(ir_node *irn, void *data)
853 struct obstack *obst = (struct obstack*)data;
854 obstack_ptr_grow(obst, irn);
857 void be_live_chk_compare(be_lv_t *lv, lv_chk_t *lvc)
859 ir_graph *irg = lv->irg;
868 irg_block_walk_graph(irg, collect_node, NULL, &obst);
869 obstack_ptr_grow(&obst, NULL);
870 blocks = (ir_node**)obstack_finish(&obst);
872 irg_walk_graph(irg, collect_node, NULL, &obst);
873 obstack_ptr_grow(&obst, NULL);
874 nodes = (ir_node**)obstack_finish(&obst);
876 stat_ev_ctx_push("be_lv_chk_compare");
877 for (j = 0; nodes[j]; ++j) {
878 ir_node *irn = nodes[j];
882 for (i = 0; blocks[i]; ++i) {
883 ir_node *bl = blocks[i];
884 int lvr_in = be_is_live_in (lv, bl, irn);
885 int lvr_out = be_is_live_out(lv, bl, irn);
886 int lvr_end = be_is_live_end(lv, bl, irn);
888 int lvc_in = lv_chk_bl_in (lvc, bl, irn);
889 int lvc_out = lv_chk_bl_out(lvc, bl, irn);
890 int lvc_end = lv_chk_bl_end(lvc, bl, irn);
892 if (lvr_in - lvc_in != 0)
893 ir_fprintf(stderr, "live in info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_in, lvc_in);
895 if (lvr_end - lvc_end != 0)
896 ir_fprintf(stderr, "live end info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_end, lvc_end);
898 if (lvr_out - lvc_out != 0)
899 ir_fprintf(stderr, "live out info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_out, lvc_out);
902 stat_ev_ctx_pop("be_lv_chk_compare");
904 obstack_free(&obst, NULL);
907 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_live)
908 void be_init_live(void)
910 FIRM_DBG_REGISTER(dbg, "firm.be.liveness");