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
28 /* statev is expensive here, only enable when needed */
29 #define DISABLE_STATEV
31 #include "iredges_t.h"
33 #include "irprintf_t.h"
35 #include "irnodeset.h"
47 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
49 #define LV_STD_SIZE 64
51 /* if defined, use binary search for already live nodes, else linear */
52 #define LV_USE_BINARY_SEARCH
53 #undef LV_INTESIVE_CHECKS
55 void be_live_chk_compare(be_lv_t *lv, lv_chk_t *lvc);
58 * Filter out some nodes for which we never need liveness.
60 * @param irn the node t check
61 * @return 0 if no liveness info is needed, 1 else
63 static inline int is_liveness_node(const ir_node *irn)
65 switch (get_irn_opcode(irn)) {
77 int (be_is_live_in)(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_in);
82 int (be_is_live_out)(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_out);
87 int (be_is_live_end)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
89 return _be_is_live_xxx(lv, block, irn, be_lv_state_end);
93 #ifdef LV_USE_BINARY_SEARCH
94 static inline unsigned _be_liveness_bsearch(be_lv_info_t *arr, unsigned idx)
96 be_lv_info_t *payload = arr + 1;
98 unsigned n = arr[0].head.n_members;
107 int md = lo + ((hi - lo) >> 1);
108 unsigned md_idx = payload[md].node.idx;
112 else if (idx < md_idx)
116 assert(payload[res].node.idx == idx);
123 #ifdef LV_INTESIVE_CHECKS
126 for (i = res; i < n; ++i)
127 assert(payload[i].node.idx >= idx);
129 for (i = 0; i < res; ++i)
130 assert(payload[i].node.idx < idx);
140 * This function searches linearly for the node in the array.
142 static inline unsigned _be_liveness_bsearch(be_lv_info_t *arr, unsigned idx)
144 unsigned n = arr[0].head.n_members;
147 for (i = 0; i < n; ++i) {
148 if (arr[i + 1].node.idx == idx)
156 be_lv_info_node_t *be_lv_get(const be_lv_t *li, const ir_node *bl,
159 be_lv_info_t *irn_live;
160 be_lv_info_node_t *res = NULL;
163 irn_live = (be_lv_info_t*)ir_nodehashmap_get(&li->map, bl);
164 if (irn_live != NULL) {
165 unsigned idx = get_irn_idx(irn);
167 /* Get the position of the index in the array. */
168 int pos = _be_liveness_bsearch(irn_live, idx);
170 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
171 be_lv_info_node_t *rec = &irn_live[pos + 1].node;
173 /* Check, if the irn is in deed in the array. */
177 stat_ev_tim_pop("be_lv_get");
182 static be_lv_info_node_t *be_lv_get_or_set(be_lv_t *li, ir_node *bl,
185 be_lv_info_t *irn_live = (be_lv_info_t*)ir_nodehashmap_get(&li->map, bl);
186 if (irn_live == NULL) {
187 irn_live = OALLOCNZ(&li->obst, be_lv_info_t, LV_STD_SIZE);
188 irn_live[0].head.n_size = LV_STD_SIZE-1;
189 ir_nodehashmap_insert(&li->map, bl, irn_live);
192 unsigned idx = get_irn_idx(irn);
194 /* Get the position of the index in the array. */
195 unsigned pos = _be_liveness_bsearch(irn_live, idx);
197 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
198 be_lv_info_node_t *res = &irn_live[pos + 1].node;
200 /* Check, if the irn is in deed in the array. */
201 if (res->idx != idx) {
202 be_lv_info_t *payload;
203 unsigned n_members = irn_live[0].head.n_members;
204 unsigned n_size = irn_live[0].head.n_size;
207 if (n_members + 1 >= n_size) {
208 /* double the array size. Remember that the first entry is
209 * metadata about the array and not a real array element */
210 unsigned old_size_bytes = (n_size + 1) * sizeof(irn_live[0]);
211 unsigned new_size = (2 * n_size) + 1;
212 size_t new_size_bytes = new_size * sizeof(irn_live[0]);
213 be_lv_info_t *nw = OALLOCN(&li->obst, be_lv_info_t, new_size);
214 memcpy(nw, irn_live, old_size_bytes);
215 memset(((char*) nw) + old_size_bytes, 0,
216 new_size_bytes - old_size_bytes);
217 nw[0].head.n_size = new_size - 1;
219 ir_nodehashmap_insert(&li->map, bl, nw);
222 payload = &irn_live[1];
223 for (i = n_members; i > pos; --i) {
224 payload[i] = payload[i - 1];
227 ++irn_live[0].head.n_members;
229 res = &payload[pos].node;
234 #ifdef LV_INTESIVE_CHECKS
237 unsigned n = irn_live[0].head.n_members;
239 be_lv_info_t *payload = &irn_live[1];
241 for (i = 0; i < n; ++i) {
242 assert(payload[i].node.idx >= last);
243 last = payload[i].node.idx;
252 * Removes a node from the list of live variables of a block.
253 * @return 1 if the node was live at that block, 0 if not.
255 static int be_lv_remove(be_lv_t *li, const ir_node *bl,
258 be_lv_info_t *irn_live = (be_lv_info_t*)ir_nodehashmap_get(&li->map, bl);
260 if (irn_live != NULL) {
261 unsigned n = irn_live[0].head.n_members;
262 unsigned idx = get_irn_idx(irn);
263 unsigned pos = _be_liveness_bsearch(irn_live, idx);
264 be_lv_info_t *payload = irn_live + 1;
265 be_lv_info_node_t *res = &payload[pos].node;
267 /* The node is in deed in the block's array. Let's remove it. */
268 if (res->idx == idx) {
271 for (i = pos + 1; i < n; ++i)
272 payload[i - 1] = payload[i];
274 payload[n - 1].node.idx = 0;
275 payload[n - 1].node.flags = 0;
277 --irn_live[0].head.n_members;
278 DBG((dbg, LEVEL_3, "\tdeleting %+F from %+F at pos %d\n", irn, bl, pos));
286 static void register_node(be_lv_t *lv, const ir_node *irn)
288 unsigned idx = get_irn_idx(irn);
289 if (idx >= bitset_size(lv->nodes)) {
290 bitset_t *nw = bitset_malloc(2 * idx);
291 bitset_copy_into(nw, lv->nodes);
292 bitset_free(lv->nodes);
296 bitset_set(lv->nodes, idx);
300 * Mark a node as live-in in a block.
302 static inline void mark_live_in(be_lv_t *lv, ir_node *block, ir_node *irn)
304 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
305 DBG((dbg, LEVEL_2, "marking %+F live in at %+F\n", irn, block));
306 n->flags |= be_lv_state_in;
307 register_node(lv, irn);
311 * Mark a node as live-out in a block.
313 static inline void mark_live_out(be_lv_t *lv, ir_node *block, ir_node *irn)
315 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
316 DBG((dbg, LEVEL_2, "marking %+F live out at %+F\n", irn, block));
317 n->flags |= be_lv_state_out | be_lv_state_end;
318 register_node(lv, irn);
322 * Mark a node as live-end in a block.
324 static inline void mark_live_end(be_lv_t *lv, ir_node *block, ir_node *irn)
326 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
327 DBG((dbg, LEVEL_2, "marking %+F live end at %+F\n", irn, block));
328 n->flags |= be_lv_state_end;
329 register_node(lv, irn);
333 be_lv_t *lv; /**< The liveness object. */
334 ir_node *def; /**< The node (value). */
335 ir_node *def_block; /**< The block of def. */
336 bitset_t *visited; /**< A set were all visited blocks are recorded. */
340 * Mark a node (value) live out at a certain block. Do this also
341 * transitively, i.e. if the block is not the block of the value's
342 * definition, all predecessors are also marked live.
343 * @param block The block to mark the value live out of.
344 * @param is_true_out Is the node real out there or only live at the end
347 static void live_end_at_block(ir_node *block, int is_true_out)
350 ir_node *def = re.def;
353 mark_live_end(lv, block, def);
355 mark_live_out(lv, block, def);
357 visited = re.visited;
358 if (!bitset_is_set(visited, get_irn_idx(block))) {
359 bitset_set(visited, get_irn_idx(block));
362 * If this block is not the definition block, we have to go up
365 if (re.def_block != block) {
368 mark_live_in(lv, block, def);
370 for (i = get_Block_n_cfgpreds(block) - 1; i >= 0; --i)
371 live_end_at_block(get_Block_cfgpred_block(block, i), 1);
376 typedef struct lv_walker_t {
381 typedef struct lv_remove_walker_t {
384 } lv_remove_walker_t;
388 * Liveness analysis for a value.
389 * Compute the set of all blocks a value is live in.
390 * @param irn The node (value).
392 static void liveness_for_node(ir_node *irn)
394 const ir_edge_t *edge;
397 bitset_clear_all(re.visited);
398 def_block = get_nodes_block(irn);
401 re.def_block = def_block;
403 /* Go over all uses of the value */
404 foreach_out_edge(irn, edge) {
405 ir_node *use = edge->src;
408 DBG((dbg, LEVEL_4, "%+F: use at %+F, pos %d in %+F\n", irn, use, edge->pos, get_block(use)));
409 assert(get_irn_n(use, edge->pos) == irn);
412 * If the usage is no data node, skip this use, since it does not
413 * affect the liveness of the node.
415 if (!is_liveness_node(use))
418 /* Get the block where the usage is in. */
419 use_block = get_nodes_block(use);
422 * If the use is a phi function, determine the corresponding block
423 * through which the value reaches the phi function and mark the
424 * value as live out of that block.
427 ir_node *pred_block = get_Block_cfgpred_block(use_block, edge->pos);
428 live_end_at_block(pred_block, 0);
432 * Else, the value is live in at this block. Mark it and call live
433 * out on the predecessors.
435 else if (def_block != use_block) {
438 mark_live_in(re.lv, use_block, irn);
440 for (i = get_Block_n_cfgpreds(use_block) - 1; i >= 0; --i) {
441 ir_node *pred_block = get_Block_cfgpred_block(use_block, i);
442 live_end_at_block(pred_block, 1);
448 static void lv_remove_irn_walker(ir_node *bl, void *data)
450 lv_remove_walker_t *w = (lv_remove_walker_t*)data;
451 be_lv_remove(w->lv, bl, w->irn);
454 static const char *lv_flags_to_str(unsigned flags)
456 static const char *states[] = {
467 return states[flags & 7];
470 static void lv_dump_block(void *context, FILE *f, const ir_node *bl)
473 be_lv_t *lv = (be_lv_t*)context;
474 be_lv_info_t *info = (be_lv_info_t*)ir_nodehashmap_get(&lv->map, bl);
476 fprintf(f, "liveness:\n");
478 unsigned n = info[0].head.n_members;
481 for (i = 0; i < n; ++i) {
482 be_lv_info_node_t *n = &info[i+1].node;
483 ir_fprintf(f, "%s %+F\n", lv_flags_to_str(n->flags), get_idx_irn(lv->irg, n->idx));
490 * Walker, collect all nodes for which we want calculate liveness info
493 static void collect_liveness_nodes(ir_node *irn, void *data)
495 ir_node **nodes = (ir_node**)data;
496 if (is_liveness_node(irn))
497 nodes[get_irn_idx(irn)] = irn;
500 static void compute_liveness(be_lv_t *lv)
506 n = get_irg_last_idx(lv->irg);
507 nodes = NEW_ARR_F(ir_node *, n);
508 memset(nodes, 0, sizeof(nodes[0]) * n);
511 * inserting the variables sorted by their ID is probably
512 * more efficient since the binary sorted set insertion
513 * will not need to move around the data.
515 irg_walk_graph(lv->irg, NULL, collect_liveness_nodes, nodes);
518 re.visited = bitset_malloc(n);
520 for (i = 0; i < n; ++i) {
521 if (nodes[i] != NULL)
522 liveness_for_node(nodes[i]);
527 register_hook(hook_node_info, &lv->hook_info);
528 stat_ev_tim_pop("be_lv_sets_cons");
531 void be_liveness_assure_sets(be_lv_t *lv)
534 be_timer_push(T_LIVE);
536 lv->nodes = bitset_malloc(2 * get_irg_last_idx(lv->irg));
537 ir_nodehashmap_init(&lv->map);
538 obstack_init(&lv->obst);
539 compute_liveness(lv);
540 /* be_live_chk_compare(lv, lv->lvc); */
542 be_timer_pop(T_LIVE);
546 void be_liveness_assure_chk(be_lv_t *lv)
549 be_timer_push(t_verify);
550 be_liveness_assure_sets(lv);
551 be_timer_pop(t_verify);
557 void be_liveness_invalidate(be_lv_t *lv)
559 if (lv && lv->nodes) {
560 unregister_hook(hook_node_info, &lv->hook_info);
561 obstack_free(&lv->obst, NULL);
562 ir_nodehashmap_destroy(&lv->map);
563 bitset_free(lv->nodes);
568 /* Compute the inter block liveness for a graph. */
569 be_lv_t *be_liveness(ir_graph *irg)
571 be_lv_t *lv = XMALLOCZ(be_lv_t);
575 lv->dfs = dfs_new(&absgraph_irg_cfg_succ, irg);
576 lv->lvc = lv_chk_new(lv->irg, lv->dfs);
578 lv->hook_info.context = lv;
579 lv->hook_info.hook._hook_node_info = lv_dump_block;
584 void be_liveness_recompute(be_lv_t *lv)
588 be_timer_push(T_LIVE);
589 last_idx = get_irg_last_idx(lv->irg);
590 if (last_idx >= bitset_size(lv->nodes)) {
591 bitset_free(lv->nodes);
592 lv->nodes = bitset_malloc(last_idx * 2);
594 bitset_clear_all(lv->nodes);
596 ir_nodehashmap_destroy(&lv->map);
597 obstack_free(&lv->obst, NULL);
599 ir_nodehashmap_init(&lv->map);
600 obstack_init(&lv->obst);
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*)ir_nodehashmap_get(&fresh->map, bl);
660 be_lv_info_t *fr = (be_lv_info_t*)ir_nodehashmap_get(&fresh->map, bl);
662 if (!fr && curr && curr[0].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].head.n_members; ++i) {
667 ir_fprintf(stderr, "\t%+F\n", get_idx_irn(lv->irg, curr[1 + i].node.idx));
672 unsigned n_curr = curr[0].head.n_members;
673 unsigned n_fresh = fr[0].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].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].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];
880 for (i = 0; blocks[i]; ++i) {
881 ir_node *bl = blocks[i];
882 int lvr_in = be_is_live_in (lv, bl, irn);
883 int lvr_out = be_is_live_out(lv, bl, irn);
884 int lvr_end = be_is_live_end(lv, bl, irn);
886 int lvc_in = lv_chk_bl_in (lvc, bl, irn);
887 int lvc_out = lv_chk_bl_out(lvc, bl, irn);
888 int lvc_end = lv_chk_bl_end(lvc, bl, irn);
890 if (lvr_in - lvc_in != 0)
891 ir_fprintf(stderr, "live in info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_in, lvc_in);
893 if (lvr_end - lvc_end != 0)
894 ir_fprintf(stderr, "live end info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_end, lvc_end);
896 if (lvr_out - lvc_out != 0)
897 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");