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
33 #include "iredges_t.h"
35 #include "irprintf_t.h"
38 #include "irnodeset.h"
50 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
52 #define LV_STD_SIZE 64
54 /* if defined, use binary search for already live nodes, else linear */
55 #define LV_USE_BINARY_SEARCH
56 #undef LV_INTESIVE_CHECKS
58 void be_live_chk_compare(be_lv_t *lv, lv_chk_t *lvc);
61 * Filter out some nodes for which we never need liveness.
63 * @param irn the node t check
64 * @return 0 if no liveness info is needed, 1 else
66 static inline int is_liveness_node(const ir_node *irn)
68 switch (get_irn_opcode(irn)) {
80 int (be_is_live_in)(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_in);
85 int (be_is_live_out)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
87 return _be_is_live_xxx(lv, block, irn, be_lv_state_out);
90 int (be_is_live_end)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
92 return _be_is_live_xxx(lv, block, irn, be_lv_state_end);
96 #ifdef LV_USE_BINARY_SEARCH
97 static inline unsigned _be_liveness_bsearch(struct _be_lv_info_t *arr, unsigned idx)
99 struct _be_lv_info_t *payload = arr + 1;
101 unsigned n = arr[0].u.head.n_members;
110 int md = lo + ((hi - lo) >> 1);
111 unsigned md_idx = payload[md].u.node.idx;
115 else if (idx < md_idx)
119 assert(payload[res].u.node.idx == idx);
126 #ifdef LV_INTESIVE_CHECKS
129 for (i = res; i < n; ++i)
130 assert(payload[i].u.node.idx >= idx);
132 for (i = 0; i < res; ++i)
133 assert(payload[i].u.node.idx < idx);
143 * This function searches linearly for the node in the array.
145 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;
162 struct _be_lv_info_node_t *res = NULL;
165 irn_live = phase_get_irn_data(&li->ph, bl);
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 struct _be_lv_info_node_t *rec = &irn_live[pos + 1].u.node;
175 /* Check, if the irn is in deed in the array. */
179 stat_ev_tim_pop("be_lv_get");
184 static struct _be_lv_info_node_t *be_lv_get_or_set(struct _be_lv_t *li, ir_node *bl, ir_node *irn)
186 struct _be_lv_info_t *irn_live = phase_get_or_set_irn_data(&li->ph, bl);
188 unsigned idx = get_irn_idx(irn);
190 /* Get the position of the index in the array. */
191 unsigned pos = _be_liveness_bsearch(irn_live, idx);
193 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
194 struct _be_lv_info_node_t *res = &irn_live[pos + 1].u.node;
196 /* Check, if the irn is in deed in the array. */
197 if (res->idx != idx) {
198 struct _be_lv_info_t *payload;
199 unsigned n_members = irn_live[0].u.head.n_members;
200 unsigned n_size = irn_live[0].u.head.n_size;
203 if (n_members + 1 >= n_size) {
204 /* double the array size. Remember that the first entry is
205 * metadata about the array and not a real array element */
206 unsigned old_size_bytes = (n_size + 1) * sizeof(irn_live[0]);
207 unsigned new_size = (2 * n_size) + 1;
208 size_t new_size_bytes = new_size * sizeof(irn_live[0]);
209 struct _be_lv_info_t *nw = phase_alloc(&li->ph, new_size_bytes);
210 memcpy(nw, irn_live, old_size_bytes);
211 memset(((char*) nw) + old_size_bytes, 0,
212 new_size_bytes - old_size_bytes);
213 nw[0].u.head.n_size = new_size - 1;
215 phase_set_irn_data(&li->ph, bl, nw);
218 payload = &irn_live[1];
219 for (i = n_members; i > pos; --i) {
220 payload[i] = payload[i - 1];
223 ++irn_live[0].u.head.n_members;
225 res = &payload[pos].u.node;
230 #ifdef LV_INTESIVE_CHECKS
233 unsigned n = irn_live[0].u.head.n_members;
235 struct _be_lv_info_t *payload = &irn_live[1];
237 for (i = 0; i < n; ++i) {
238 assert(payload[i].u.node.idx >= last);
239 last = payload[i].u.node.idx;
248 * Removes a node from the list of live variables of a block.
249 * @return 1 if the node was live at that block, 0 if not.
251 static int be_lv_remove(struct _be_lv_t *li, const ir_node *bl,
254 struct _be_lv_info_t *irn_live = phase_get_irn_data(&li->ph, bl);
257 unsigned n = irn_live[0].u.head.n_members;
258 unsigned idx = get_irn_idx(irn);
259 unsigned pos = _be_liveness_bsearch(irn_live, idx);
260 struct _be_lv_info_t *payload = irn_live + 1;
261 struct _be_lv_info_node_t *res = &payload[pos].u.node;
263 /* The node is in deed in the block's array. Let's remove it. */
264 if (res->idx == idx) {
267 for (i = pos + 1; i < n; ++i)
268 payload[i - 1] = payload[i];
270 payload[n - 1].u.node.idx = 0;
271 payload[n - 1].u.node.flags = 0;
273 --irn_live[0].u.head.n_members;
274 DBG((dbg, LEVEL_3, "\tdeleting %+F from %+F at pos %d\n", irn, bl, pos));
282 static void register_node(be_lv_t *lv, const ir_node *irn)
284 unsigned idx = get_irn_idx(irn);
285 if (idx >= bitset_size(lv->nodes)) {
286 bitset_t *nw = bitset_malloc(2 * idx);
287 bitset_copy_into(nw, lv->nodes);
288 bitset_free(lv->nodes);
292 bitset_set(lv->nodes, idx);
296 * Mark a node as live-in in a block.
298 static inline void mark_live_in(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 in at %+F\n", irn, block));
302 n->flags |= be_lv_state_in;
303 register_node(lv, irn);
307 * Mark a node as live-out in a block.
309 static inline void mark_live_out(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 out at %+F\n", irn, block));
313 n->flags |= be_lv_state_out | be_lv_state_end;
314 register_node(lv, irn);
318 * Mark a node as live-end in a block.
320 static inline void mark_live_end(be_lv_t *lv, ir_node *block, ir_node *irn)
322 struct _be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
323 DBG((dbg, LEVEL_2, "marking %+F live end at %+F\n", irn, block));
324 n->flags |= be_lv_state_end;
325 register_node(lv, irn);
329 be_lv_t *lv; /**< The liveness object. */
330 ir_node *def; /**< The node (value). */
331 ir_node *def_block; /**< The block of def. */
332 bitset_t *visited; /**< A set were all visited blocks are recorded. */
336 * Mark a node (value) live out at a certain block. Do this also
337 * transitively, i.e. if the block is not the block of the value's
338 * definition, all predecessors are also marked live.
339 * @param block The block to mark the value live out of.
340 * @param is_true_out Is the node real out there or only live at the end
343 static void live_end_at_block(ir_node *block, int is_true_out)
346 ir_node *def = re.def;
349 mark_live_end(lv, block, def);
351 mark_live_out(lv, block, def);
353 visited = re.visited;
354 if (!bitset_contains_irn(visited, block)) {
355 bitset_add_irn(visited, block);
358 * If this block is not the definition block, we have to go up
361 if (re.def_block != block) {
364 mark_live_in(lv, block, def);
366 for (i = get_Block_n_cfgpreds(block) - 1; i >= 0; --i)
367 live_end_at_block(get_Block_cfgpred_block(block, i), 1);
372 typedef struct _lv_walker_t {
377 typedef struct lv_remove_walker_t {
380 } lv_remove_walker_t;
384 * Liveness analysis for a value.
385 * Compute the set of all blocks a value is live in.
386 * @param irn The node (value).
388 static void liveness_for_node(ir_node *irn)
390 const ir_edge_t *edge;
393 bitset_clear_all(re.visited);
394 def_block = get_nodes_block(irn);
397 re.def_block = def_block;
399 /* Go over all uses of the value */
400 foreach_out_edge(irn, edge) {
401 ir_node *use = edge->src;
404 DBG((dbg, LEVEL_4, "%+F: use at %+F, pos %d in %+F\n", irn, use, edge->pos, get_block(use)));
405 assert(get_irn_n(use, edge->pos) == irn);
408 * If the usage is no data node, skip this use, since it does not
409 * affect the liveness of the node.
411 if (!is_liveness_node(use))
414 /* Get the block where the usage is in. */
415 use_block = get_nodes_block(use);
418 * If the use is a phi function, determine the corresponding block
419 * through which the value reaches the phi function and mark the
420 * value as live out of that block.
423 ir_node *pred_block = get_Block_cfgpred_block(use_block, edge->pos);
424 live_end_at_block(pred_block, 0);
428 * Else, the value is live in at this block. Mark it and call live
429 * out on the predecessors.
431 else if (def_block != use_block) {
434 mark_live_in(re.lv, use_block, irn);
436 for (i = get_Block_n_cfgpreds(use_block) - 1; i >= 0; --i) {
437 ir_node *pred_block = get_Block_cfgpred_block(use_block, i);
438 live_end_at_block(pred_block, 1);
444 static void lv_remove_irn_walker(ir_node *bl, void *data)
446 lv_remove_walker_t *w = data;
447 be_lv_remove(w->lv, bl, w->irn);
450 static const char *lv_flags_to_str(unsigned flags)
452 static const char *states[] = {
463 return states[flags & 7];
466 static void lv_dump_block(void *context, FILE *f, const ir_node *bl)
469 be_lv_t *lv = context;
470 struct _be_lv_info_t *info = phase_get_irn_data(&lv->ph, bl);
472 fprintf(f, "liveness:\n");
474 unsigned n = info[0].u.head.n_members;
477 for (i = 0; i < n; ++i) {
478 struct _be_lv_info_node_t *n = &info[i+1].u.node;
479 ir_fprintf(f, "%s %+F\n", lv_flags_to_str(n->flags), get_idx_irn(lv->irg, n->idx));
485 static void *lv_phase_data_init(ir_phase *phase, const ir_node *irn, void *old)
487 struct _be_lv_info_t *info = phase_alloc(phase, LV_STD_SIZE * sizeof(info[0]));
491 memset(info, 0, LV_STD_SIZE * sizeof(info[0]));
492 info[0].u.head.n_size = LV_STD_SIZE - 1;
497 * Walker, collect all nodes for which we want calculate liveness info
500 static void collect_liveness_nodes(ir_node *irn, void *data)
502 ir_node **nodes = data;
503 if (is_liveness_node(irn))
504 nodes[get_irn_idx(irn)] = irn;
507 static void compute_liveness(be_lv_t *lv)
513 n = get_irg_last_idx(lv->irg);
514 nodes = NEW_ARR_F(ir_node *, n);
515 memset(nodes, 0, sizeof(nodes[0]) * n);
518 * inserting the variables sorted by their ID is probably
519 * more efficient since the binary sorted set insertion
520 * will not need to move around the data.
522 irg_walk_graph(lv->irg, NULL, collect_liveness_nodes, nodes);
525 re.visited = bitset_malloc(n);
527 for (i = 0; i < n; ++i) {
528 if (nodes[i] != NULL)
529 liveness_for_node(nodes[i]);
534 register_hook(hook_node_info, &lv->hook_info);
535 stat_ev_tim_pop("be_lv_sets_cons");
538 void be_liveness_assure_sets(be_lv_t *lv)
541 be_timer_push(T_LIVE);
543 lv->nodes = bitset_malloc(2 * get_irg_last_idx(lv->irg));
544 phase_init(&lv->ph, lv->irg, lv_phase_data_init);
545 compute_liveness(lv);
546 /* be_live_chk_compare(lv, lv->lvc); */
548 be_timer_pop(T_LIVE);
552 void be_liveness_assure_chk(be_lv_t *lv)
555 be_timer_push(t_verify);
556 be_liveness_assure_sets(lv);
557 be_timer_pop(t_verify);
563 void be_liveness_invalidate(be_lv_t *lv)
565 if (lv && lv->nodes) {
566 unregister_hook(hook_node_info, &lv->hook_info);
567 phase_deinit(&lv->ph);
568 bitset_free(lv->nodes);
573 /* Compute the inter block liveness for a graph. */
574 be_lv_t *be_liveness(ir_graph *irg)
576 be_lv_t *lv = XMALLOCZ(be_lv_t);
580 lv->dfs = dfs_new(&absgraph_irg_cfg_succ, irg);
581 lv->lvc = lv_chk_new(lv->irg, lv->dfs);
583 lv->hook_info.context = lv;
584 lv->hook_info.hook._hook_node_info = lv_dump_block;
589 void be_liveness_recompute(be_lv_t *lv)
593 be_timer_push(T_LIVE);
594 last_idx = get_irg_last_idx(lv->irg);
595 if (last_idx >= bitset_size(lv->nodes)) {
596 bitset_free(lv->nodes);
597 lv->nodes = bitset_malloc(last_idx * 2);
599 bitset_clear_all(lv->nodes);
601 phase_deinit(&lv->ph);
602 phase_init(&lv->ph, lv->irg, lv_phase_data_init);
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 = data;
659 be_lv_t *fresh = w->data;
661 struct _be_lv_info_t *curr = phase_get_irn_data(&lv->ph, bl);
662 struct _be_lv_info_t *fr = phase_get_irn_data(&fresh->ph, bl);
664 if (!fr && curr && curr[0].u.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].u.head.n_members; ++i) {
669 ir_fprintf(stderr, "\t%+F\n", get_idx_irn(lv->irg, curr[1 + i].u.node.idx));
674 unsigned n_curr = curr[0].u.head.n_members;
675 unsigned n_fresh = fr[0].u.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 struct _be_lv_info_node_t *n = &curr[1 + i].u.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 struct _be_lv_info_node_t *n = &fr[1 + i].u.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 = data;
713 lv_dump_block(w->lv, 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 the every predecessors of a node dominate
743 static void dom_check(ir_node *irn, void *data)
745 int *problem_found = data;
747 if (!is_Block(irn) && irn != get_irg_end(get_irn_irg(irn))) {
749 ir_node *bl = get_nodes_block(irn);
751 for (i = 0, n = get_irn_arity(irn); i < n; ++i) {
752 ir_node *op = get_irn_n(irn, i);
753 ir_node *def_bl = get_nodes_block(op);
754 ir_node *use_bl = bl;
757 use_bl = get_Block_cfgpred_block(bl, i);
759 if (get_irn_opcode(use_bl) != iro_Bad
760 && get_irn_opcode(def_bl) != iro_Bad
761 && !block_dominates(def_bl, use_bl)) {
762 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)));
769 /* Check, if the SSA dominance property is fulfilled. */
770 int be_check_dominance(ir_graph *irg)
772 int problem_found = 0;
775 irg_walk_graph(irg, dom_check, NULL, &problem_found);
777 return !problem_found;
780 void be_liveness_transfer(const arch_register_class_t *cls,
781 ir_node *node, ir_nodeset_t *nodeset)
785 /* You should better break out of your loop when hitting the first phi
787 assert(!is_Phi(node) && "liveness_transfer produces invalid results for phi nodes");
789 if (get_irn_mode(node) == mode_T) {
790 const ir_edge_t *edge;
792 foreach_out_edge(node, edge) {
793 ir_node *proj = get_edge_src_irn(edge);
795 if (arch_irn_consider_in_reg_alloc(cls, proj)) {
796 ir_nodeset_remove(nodeset, proj);
799 } else if (arch_irn_consider_in_reg_alloc(cls, node)) {
800 ir_nodeset_remove(nodeset, node);
803 arity = get_irn_arity(node);
804 for (i = 0; i < arity; ++i) {
805 ir_node *op = get_irn_n(node, i);
807 if (arch_irn_consider_in_reg_alloc(cls, op))
808 ir_nodeset_insert(nodeset, op);
814 void be_liveness_end_of_block(const be_lv_t *lv,
815 const arch_register_class_t *cls,
816 const ir_node *block, ir_nodeset_t *live)
820 assert(lv->nodes && "live sets must be computed");
821 be_lv_foreach(lv, block, be_lv_state_end, i) {
822 ir_node *node = be_lv_get_irn(lv, block, i);
823 if (!arch_irn_consider_in_reg_alloc(cls, node))
826 ir_nodeset_insert(live, node);
832 void be_liveness_nodes_live_at(const be_lv_t *lv,
833 const arch_register_class_t *cls,
834 const ir_node *pos, ir_nodeset_t *live)
836 const ir_node *bl = is_Block(pos) ? pos : get_nodes_block(pos);
839 be_liveness_end_of_block(lv, cls, bl, live);
840 sched_foreach_reverse(bl, irn) {
842 * If we encounter the node we want to insert the Perm after,
843 * exit immediately, so that this node is still live
848 be_liveness_transfer(cls, irn, live);
852 static void collect_node(ir_node *irn, void *data)
854 struct obstack *obst = data;
855 obstack_ptr_grow(obst, irn);
858 void be_live_chk_compare(be_lv_t *lv, lv_chk_t *lvc)
860 ir_graph *irg = lv->irg;
869 irg_block_walk_graph(irg, collect_node, NULL, &obst);
870 obstack_ptr_grow(&obst, NULL);
871 blocks = obstack_finish(&obst);
873 irg_walk_graph(irg, collect_node, NULL, &obst);
874 obstack_ptr_grow(&obst, NULL);
875 nodes = obstack_finish(&obst);
877 stat_ev_ctx_push("be_lv_chk_compare");
878 for (j = 0; nodes[j]; ++j) {
879 ir_node *irn = nodes[j];
880 for (i = 0; blocks[i]; ++i) {
881 ir_node *bl = blocks[i];
883 if (!is_Block(irn)) {
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);
903 stat_ev_ctx_pop("be_lv_chk_compare");
905 obstack_free(&obst, NULL);
908 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_live);
909 void be_init_live(void)
911 FIRM_DBG_REGISTER(dbg, "firm.be.liveness");