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].u.head.n_members;
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(be_lv_info_t *arr, unsigned idx)
146 unsigned n = arr[0].u.head.n_members;
149 for (i = 0; i < n; ++i) {
150 if (arr[i + 1].u.node.idx == idx)
158 be_lv_info_node_t *be_lv_get(const be_lv_t *li, const ir_node *bl, const ir_node *irn)
160 be_lv_info_t *irn_live;
161 be_lv_info_node_t *res = NULL;
164 irn_live = (be_lv_info_t*)phase_get_irn_data(&li->ph, bl);
166 unsigned idx = get_irn_idx(irn);
168 /* Get the position of the index in the array. */
169 int pos = _be_liveness_bsearch(irn_live, idx);
171 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
172 be_lv_info_node_t *rec = &irn_live[pos + 1].u.node;
174 /* Check, if the irn is in deed in the array. */
178 stat_ev_tim_pop("be_lv_get");
183 static be_lv_info_node_t *be_lv_get_or_set(be_lv_t *li, ir_node *bl, ir_node *irn)
185 be_lv_info_t *irn_live = (be_lv_info_t*)phase_get_or_set_irn_data(&li->ph, bl);
187 unsigned idx = get_irn_idx(irn);
189 /* Get the position of the index in the array. */
190 unsigned pos = _be_liveness_bsearch(irn_live, idx);
192 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
193 be_lv_info_node_t *res = &irn_live[pos + 1].u.node;
195 /* Check, if the irn is in deed in the array. */
196 if (res->idx != idx) {
197 be_lv_info_t *payload;
198 unsigned n_members = irn_live[0].u.head.n_members;
199 unsigned n_size = irn_live[0].u.head.n_size;
202 if (n_members + 1 >= n_size) {
203 /* double the array size. Remember that the first entry is
204 * metadata about the array and not a real array element */
205 unsigned old_size_bytes = (n_size + 1) * sizeof(irn_live[0]);
206 unsigned new_size = (2 * n_size) + 1;
207 size_t new_size_bytes = new_size * sizeof(irn_live[0]);
208 be_lv_info_t *nw = (be_lv_info_t*)phase_alloc(&li->ph, new_size_bytes);
209 memcpy(nw, irn_live, old_size_bytes);
210 memset(((char*) nw) + old_size_bytes, 0,
211 new_size_bytes - old_size_bytes);
212 nw[0].u.head.n_size = new_size - 1;
214 phase_set_irn_data(&li->ph, bl, nw);
217 payload = &irn_live[1];
218 for (i = n_members; i > pos; --i) {
219 payload[i] = payload[i - 1];
222 ++irn_live[0].u.head.n_members;
224 res = &payload[pos].u.node;
229 #ifdef LV_INTESIVE_CHECKS
232 unsigned n = irn_live[0].u.head.n_members;
234 be_lv_info_t *payload = &irn_live[1];
236 for (i = 0; i < n; ++i) {
237 assert(payload[i].u.node.idx >= last);
238 last = payload[i].u.node.idx;
247 * Removes a node from the list of live variables of a block.
248 * @return 1 if the node was live at that block, 0 if not.
250 static int be_lv_remove(be_lv_t *li, const ir_node *bl,
253 be_lv_info_t *irn_live = (be_lv_info_t*)phase_get_irn_data(&li->ph, bl);
256 unsigned n = irn_live[0].u.head.n_members;
257 unsigned idx = get_irn_idx(irn);
258 unsigned pos = _be_liveness_bsearch(irn_live, idx);
259 be_lv_info_t *payload = irn_live + 1;
260 be_lv_info_node_t *res = &payload[pos].u.node;
262 /* The node is in deed in the block's array. Let's remove it. */
263 if (res->idx == idx) {
266 for (i = pos + 1; i < n; ++i)
267 payload[i - 1] = payload[i];
269 payload[n - 1].u.node.idx = 0;
270 payload[n - 1].u.node.flags = 0;
272 --irn_live[0].u.head.n_members;
273 DBG((dbg, LEVEL_3, "\tdeleting %+F from %+F at pos %d\n", irn, bl, pos));
281 static void register_node(be_lv_t *lv, const ir_node *irn)
283 unsigned idx = get_irn_idx(irn);
284 if (idx >= bitset_size(lv->nodes)) {
285 bitset_t *nw = bitset_malloc(2 * idx);
286 bitset_copy_into(nw, lv->nodes);
287 bitset_free(lv->nodes);
291 bitset_set(lv->nodes, idx);
295 * Mark a node as live-in in a block.
297 static inline void mark_live_in(be_lv_t *lv, ir_node *block, ir_node *irn)
299 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
300 DBG((dbg, LEVEL_2, "marking %+F live in at %+F\n", irn, block));
301 n->flags |= be_lv_state_in;
302 register_node(lv, irn);
306 * Mark a node as live-out in a block.
308 static inline void mark_live_out(be_lv_t *lv, ir_node *block, ir_node *irn)
310 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
311 DBG((dbg, LEVEL_2, "marking %+F live out at %+F\n", irn, block));
312 n->flags |= be_lv_state_out | be_lv_state_end;
313 register_node(lv, irn);
317 * Mark a node as live-end in a block.
319 static inline void mark_live_end(be_lv_t *lv, ir_node *block, ir_node *irn)
321 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
322 DBG((dbg, LEVEL_2, "marking %+F live end at %+F\n", irn, block));
323 n->flags |= be_lv_state_end;
324 register_node(lv, irn);
328 be_lv_t *lv; /**< The liveness object. */
329 ir_node *def; /**< The node (value). */
330 ir_node *def_block; /**< The block of def. */
331 bitset_t *visited; /**< A set were all visited blocks are recorded. */
335 * Mark a node (value) live out at a certain block. Do this also
336 * transitively, i.e. if the block is not the block of the value's
337 * definition, all predecessors are also marked live.
338 * @param block The block to mark the value live out of.
339 * @param is_true_out Is the node real out there or only live at the end
342 static void live_end_at_block(ir_node *block, int is_true_out)
345 ir_node *def = re.def;
348 mark_live_end(lv, block, def);
350 mark_live_out(lv, block, def);
352 visited = re.visited;
353 if (!bitset_contains_irn(visited, block)) {
354 bitset_add_irn(visited, block);
357 * If this block is not the definition block, we have to go up
360 if (re.def_block != block) {
363 mark_live_in(lv, block, def);
365 for (i = get_Block_n_cfgpreds(block) - 1; i >= 0; --i)
366 live_end_at_block(get_Block_cfgpred_block(block, i), 1);
371 typedef struct lv_walker_t {
376 typedef struct lv_remove_walker_t {
379 } lv_remove_walker_t;
383 * Liveness analysis for a value.
384 * Compute the set of all blocks a value is live in.
385 * @param irn The node (value).
387 static void liveness_for_node(ir_node *irn)
389 const ir_edge_t *edge;
392 bitset_clear_all(re.visited);
393 def_block = get_nodes_block(irn);
396 re.def_block = def_block;
398 /* Go over all uses of the value */
399 foreach_out_edge(irn, edge) {
400 ir_node *use = edge->src;
403 DBG((dbg, LEVEL_4, "%+F: use at %+F, pos %d in %+F\n", irn, use, edge->pos, get_block(use)));
404 assert(get_irn_n(use, edge->pos) == irn);
407 * If the usage is no data node, skip this use, since it does not
408 * affect the liveness of the node.
410 if (!is_liveness_node(use))
413 /* Get the block where the usage is in. */
414 use_block = get_nodes_block(use);
417 * If the use is a phi function, determine the corresponding block
418 * through which the value reaches the phi function and mark the
419 * value as live out of that block.
422 ir_node *pred_block = get_Block_cfgpred_block(use_block, edge->pos);
423 live_end_at_block(pred_block, 0);
427 * Else, the value is live in at this block. Mark it and call live
428 * out on the predecessors.
430 else if (def_block != use_block) {
433 mark_live_in(re.lv, use_block, irn);
435 for (i = get_Block_n_cfgpreds(use_block) - 1; i >= 0; --i) {
436 ir_node *pred_block = get_Block_cfgpred_block(use_block, i);
437 live_end_at_block(pred_block, 1);
443 static void lv_remove_irn_walker(ir_node *bl, void *data)
445 lv_remove_walker_t *w = (lv_remove_walker_t*)data;
446 be_lv_remove(w->lv, bl, w->irn);
449 static const char *lv_flags_to_str(unsigned flags)
451 static const char *states[] = {
462 return states[flags & 7];
465 static void lv_dump_block(void *context, FILE *f, const ir_node *bl)
468 be_lv_t *lv = (be_lv_t*)context;
469 be_lv_info_t *info = (be_lv_info_t*)phase_get_irn_data(&lv->ph, bl);
471 fprintf(f, "liveness:\n");
473 unsigned n = info[0].u.head.n_members;
476 for (i = 0; i < n; ++i) {
477 be_lv_info_node_t *n = &info[i+1].u.node;
478 ir_fprintf(f, "%s %+F\n", lv_flags_to_str(n->flags), get_idx_irn(lv->irg, n->idx));
484 static void *lv_phase_data_init(ir_phase *phase, const ir_node *irn)
486 be_lv_info_t *info = (be_lv_info_t*)phase_alloc(phase, LV_STD_SIZE * sizeof(info[0]));
489 memset(info, 0, LV_STD_SIZE * sizeof(info[0]));
490 info[0].u.head.n_size = LV_STD_SIZE - 1;
495 * Walker, collect all nodes for which we want calculate liveness info
498 static void collect_liveness_nodes(ir_node *irn, void *data)
500 ir_node **nodes = (ir_node**)data;
501 if (is_liveness_node(irn))
502 nodes[get_irn_idx(irn)] = irn;
505 static void compute_liveness(be_lv_t *lv)
511 n = get_irg_last_idx(lv->irg);
512 nodes = NEW_ARR_F(ir_node *, n);
513 memset(nodes, 0, sizeof(nodes[0]) * n);
516 * inserting the variables sorted by their ID is probably
517 * more efficient since the binary sorted set insertion
518 * will not need to move around the data.
520 irg_walk_graph(lv->irg, NULL, collect_liveness_nodes, nodes);
523 re.visited = bitset_malloc(n);
525 for (i = 0; i < n; ++i) {
526 if (nodes[i] != NULL)
527 liveness_for_node(nodes[i]);
532 register_hook(hook_node_info, &lv->hook_info);
533 stat_ev_tim_pop("be_lv_sets_cons");
536 void be_liveness_assure_sets(be_lv_t *lv)
539 be_timer_push(T_LIVE);
541 lv->nodes = bitset_malloc(2 * get_irg_last_idx(lv->irg));
542 phase_init(&lv->ph, lv->irg, lv_phase_data_init);
543 compute_liveness(lv);
544 /* be_live_chk_compare(lv, lv->lvc); */
546 be_timer_pop(T_LIVE);
550 void be_liveness_assure_chk(be_lv_t *lv)
553 be_timer_push(t_verify);
554 be_liveness_assure_sets(lv);
555 be_timer_pop(t_verify);
561 void be_liveness_invalidate(be_lv_t *lv)
563 if (lv && lv->nodes) {
564 unregister_hook(hook_node_info, &lv->hook_info);
565 phase_deinit(&lv->ph);
566 bitset_free(lv->nodes);
571 /* Compute the inter block liveness for a graph. */
572 be_lv_t *be_liveness(ir_graph *irg)
574 be_lv_t *lv = XMALLOCZ(be_lv_t);
578 lv->dfs = dfs_new(&absgraph_irg_cfg_succ, irg);
579 lv->lvc = lv_chk_new(lv->irg, lv->dfs);
581 lv->hook_info.context = lv;
582 lv->hook_info.hook._hook_node_info = lv_dump_block;
587 void be_liveness_recompute(be_lv_t *lv)
591 be_timer_push(T_LIVE);
592 last_idx = get_irg_last_idx(lv->irg);
593 if (last_idx >= bitset_size(lv->nodes)) {
594 bitset_free(lv->nodes);
595 lv->nodes = bitset_malloc(last_idx * 2);
597 bitset_clear_all(lv->nodes);
599 phase_deinit(&lv->ph);
600 phase_init(&lv->ph, lv->irg, lv_phase_data_init);
601 compute_liveness(lv);
603 be_timer_pop(T_LIVE);
607 void be_liveness_free(be_lv_t *lv)
609 be_liveness_invalidate(lv);
611 lv_chk_free(lv->lvc);
617 void be_liveness_remove(be_lv_t *lv, const ir_node *irn)
620 unsigned idx = get_irn_idx(irn);
621 lv_remove_walker_t w;
624 * Removes a single irn from the liveness information.
625 * Since an irn can only be live at blocks dominated by the block of its
626 * definition, we only have to process that dominance subtree.
630 dom_tree_walk(get_nodes_block(irn), lv_remove_irn_walker, NULL, &w);
631 if (idx < bitset_size(lv->nodes))
632 bitset_clear(lv->nodes, idx);
636 void be_liveness_introduce(be_lv_t *lv, ir_node *irn)
638 /* Don't compute liveness information for non-data nodes. */
639 if (lv->nodes && is_liveness_node(irn)) {
641 re.visited = bitset_malloc(get_irg_last_idx(lv->irg));
642 liveness_for_node(irn);
643 bitset_free(re.visited);
647 void be_liveness_update(be_lv_t *lv, ir_node *irn)
649 be_liveness_remove(lv, irn);
650 be_liveness_introduce(lv, irn);
653 static void lv_check_walker(ir_node *bl, void *data)
655 lv_walker_t *w = (lv_walker_t*)data;
657 be_lv_t *fresh = (be_lv_t*)w->data;
659 be_lv_info_t *curr = (be_lv_info_t*)phase_get_irn_data(&lv->ph, bl);
660 be_lv_info_t *fr = (be_lv_info_t*)phase_get_irn_data(&fresh->ph, bl);
662 if (!fr && curr && curr[0].u.head.n_members > 0) {
665 ir_fprintf(stderr, "%+F liveness should be empty but current liveness contains:\n", bl);
666 for (i = 0; i < curr[0].u.head.n_members; ++i) {
667 ir_fprintf(stderr, "\t%+F\n", get_idx_irn(lv->irg, curr[1 + i].u.node.idx));
672 unsigned n_curr = curr[0].u.head.n_members;
673 unsigned n_fresh = fr[0].u.head.n_members;
677 if (n_curr != n_fresh) {
678 ir_fprintf(stderr, "%+F: liveness set sizes differ. curr %d, correct %d\n", bl, n_curr, n_fresh);
680 ir_fprintf(stderr, "current:\n");
681 for (i = 0; i < n_curr; ++i) {
682 be_lv_info_node_t *n = &curr[1 + i].u.node;
683 ir_fprintf(stderr, "%+F %u %+F %s\n", bl, i, get_idx_irn(lv->irg, n->idx), lv_flags_to_str(n->flags));
686 ir_fprintf(stderr, "correct:\n");
687 for (i = 0; i < n_fresh; ++i) {
688 be_lv_info_node_t *n = &fr[1 + i].u.node;
689 ir_fprintf(stderr, "%+F %u %+F %s\n", bl, i, get_idx_irn(lv->irg, n->idx), lv_flags_to_str(n->flags));
695 void be_liveness_check(be_lv_t *lv)
698 be_lv_t *fresh = be_liveness(lv->irg);
702 irg_block_walk_graph(lv->irg, lv_check_walker, NULL, &w);
703 be_liveness_free(fresh);
707 static void lv_dump_block_walker(ir_node *irn, void *data)
709 lv_walker_t *w = (lv_walker_t*)data;
711 lv_dump_block(w->lv, (FILE*)w->data, irn);
715 /* Dump the liveness information for a graph. */
716 void be_liveness_dump(const be_lv_t *lv, FILE *f)
720 w.lv = (be_lv_t *) lv;
722 irg_block_walk_graph(lv->irg, lv_dump_block_walker, NULL, &w);
725 /* Dump the liveness information for a graph. */
726 void be_liveness_dumpto(const be_lv_t *lv, const char *cls_name)
730 ir_snprintf(buf, sizeof(buf), "%F_%s-live.txt", lv->irg, cls_name);
731 if ((f = fopen(buf, "wt")) != NULL) {
732 be_liveness_dump(lv, f);
738 * Walker: checks that every predecessors of a node dominates the node.
740 static void dom_check(ir_node *irn, void *data)
742 int *problem_found = (int*)data;
744 if (!is_Block(irn) && irn != get_irg_end(get_irn_irg(irn))) {
746 ir_node *bl = get_nodes_block(irn);
748 for (i = 0, n = get_irn_arity(irn); i < n; ++i) {
749 ir_node *op = get_irn_n(irn, i);
750 ir_node *def_bl = get_nodes_block(op);
751 ir_node *use_bl = bl;
754 use_bl = get_Block_cfgpred_block(bl, i);
756 if (get_irn_opcode(use_bl) != iro_Bad
757 && get_irn_opcode(def_bl) != iro_Bad
758 && !block_dominates(def_bl, use_bl)) {
759 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)));
766 /* Check, if the SSA dominance property is fulfilled. */
767 int be_check_dominance(ir_graph *irg)
769 int problem_found = 0;
772 irg_walk_graph(irg, dom_check, NULL, &problem_found);
774 return !problem_found;
777 void be_liveness_transfer(const arch_register_class_t *cls,
778 ir_node *node, ir_nodeset_t *nodeset)
782 /* You should better break out of your loop when hitting the first phi
784 assert(!is_Phi(node) && "liveness_transfer produces invalid results for phi nodes");
786 if (get_irn_mode(node) == mode_T) {
787 const ir_edge_t *edge;
789 foreach_out_edge(node, edge) {
790 ir_node *proj = get_edge_src_irn(edge);
792 if (arch_irn_consider_in_reg_alloc(cls, proj)) {
793 ir_nodeset_remove(nodeset, proj);
796 } else if (arch_irn_consider_in_reg_alloc(cls, node)) {
797 ir_nodeset_remove(nodeset, node);
800 arity = get_irn_arity(node);
801 for (i = 0; i < arity; ++i) {
802 ir_node *op = get_irn_n(node, i);
804 if (arch_irn_consider_in_reg_alloc(cls, op))
805 ir_nodeset_insert(nodeset, op);
811 void be_liveness_end_of_block(const be_lv_t *lv,
812 const arch_register_class_t *cls,
813 const ir_node *block, ir_nodeset_t *live)
817 assert(lv->nodes && "live sets must be computed");
818 be_lv_foreach(lv, block, be_lv_state_end, i) {
819 ir_node *node = be_lv_get_irn(lv, block, i);
820 if (!arch_irn_consider_in_reg_alloc(cls, node))
823 ir_nodeset_insert(live, node);
829 void be_liveness_nodes_live_at(const be_lv_t *lv,
830 const arch_register_class_t *cls,
831 const ir_node *pos, ir_nodeset_t *live)
833 const ir_node *bl = is_Block(pos) ? pos : get_nodes_block(pos);
836 be_liveness_end_of_block(lv, cls, bl, live);
837 sched_foreach_reverse(bl, irn) {
839 * If we encounter the node we want to insert the Perm after,
840 * exit immediately, so that this node is still live
845 be_liveness_transfer(cls, irn, live);
849 static void collect_node(ir_node *irn, void *data)
851 struct obstack *obst = (struct obstack*)data;
852 obstack_ptr_grow(obst, irn);
855 void be_live_chk_compare(be_lv_t *lv, lv_chk_t *lvc)
857 ir_graph *irg = lv->irg;
866 irg_block_walk_graph(irg, collect_node, NULL, &obst);
867 obstack_ptr_grow(&obst, NULL);
868 blocks = (ir_node**)obstack_finish(&obst);
870 irg_walk_graph(irg, collect_node, NULL, &obst);
871 obstack_ptr_grow(&obst, NULL);
872 nodes = (ir_node**)obstack_finish(&obst);
874 stat_ev_ctx_push("be_lv_chk_compare");
875 for (j = 0; nodes[j]; ++j) {
876 ir_node *irn = nodes[j];
877 for (i = 0; blocks[i]; ++i) {
878 ir_node *bl = blocks[i];
880 if (!is_Block(irn)) {
881 int lvr_in = be_is_live_in (lv, bl, irn);
882 int lvr_out = be_is_live_out(lv, bl, irn);
883 int lvr_end = be_is_live_end(lv, bl, irn);
885 int lvc_in = lv_chk_bl_in (lvc, bl, irn);
886 int lvc_out = lv_chk_bl_out(lvc, bl, irn);
887 int lvc_end = lv_chk_bl_end(lvc, bl, irn);
889 if (lvr_in - lvc_in != 0)
890 ir_fprintf(stderr, "live in info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_in, lvc_in);
892 if (lvr_end - lvc_end != 0)
893 ir_fprintf(stderr, "live end info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_end, lvc_end);
895 if (lvr_out - lvc_out != 0)
896 ir_fprintf(stderr, "live out info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_out, lvc_out);
900 stat_ev_ctx_pop("be_lv_chk_compare");
902 obstack_free(&obst, NULL);
905 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_live)
906 void be_init_live(void)
908 FIRM_DBG_REGISTER(dbg, "firm.be.liveness");