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"
36 #include "irnodeset.h"
48 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
50 #define LV_STD_SIZE 64
52 /* if defined, use binary search for already live nodes, else linear */
53 #define LV_USE_BINARY_SEARCH
54 #undef LV_INTESIVE_CHECKS
56 void be_live_chk_compare(be_lv_t *lv, lv_chk_t *lvc);
59 * Filter out some nodes for which we never need liveness.
61 * @param irn the node t check
62 * @return 0 if no liveness info is needed, 1 else
64 static inline int is_liveness_node(const ir_node *irn)
66 switch (get_irn_opcode(irn)) {
78 int (be_is_live_in)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
80 return _be_is_live_xxx(lv, block, irn, be_lv_state_in);
83 int (be_is_live_out)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
85 return _be_is_live_xxx(lv, block, irn, be_lv_state_out);
88 int (be_is_live_end)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
90 return _be_is_live_xxx(lv, block, irn, be_lv_state_end);
94 #ifdef LV_USE_BINARY_SEARCH
95 static inline unsigned _be_liveness_bsearch(be_lv_info_t *arr, unsigned idx)
97 be_lv_info_t *payload = arr + 1;
99 unsigned n = arr[0].head.n_members;
108 int md = lo + ((hi - lo) >> 1);
109 unsigned md_idx = payload[md].node.idx;
113 else if (idx < md_idx)
117 assert(payload[res].node.idx == idx);
124 #ifdef LV_INTESIVE_CHECKS
127 for (i = res; i < n; ++i)
128 assert(payload[i].node.idx >= idx);
130 for (i = 0; i < res; ++i)
131 assert(payload[i].node.idx < idx);
141 * This function searches linearly for the node in the array.
143 static inline unsigned _be_liveness_bsearch(be_lv_info_t *arr, unsigned idx)
145 unsigned n = arr[0].head.n_members;
148 for (i = 0; i < n; ++i) {
149 if (arr[i + 1].node.idx == idx)
157 be_lv_info_node_t *be_lv_get(const be_lv_t *li, const ir_node *bl,
160 be_lv_info_t *irn_live;
161 be_lv_info_node_t *res = NULL;
164 irn_live = (be_lv_info_t*)ir_nodehashmap_get(&li->map, bl);
165 if (irn_live != NULL) {
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].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,
186 be_lv_info_t *irn_live = (be_lv_info_t*)ir_nodehashmap_get(&li->map, bl);
187 if (irn_live == NULL) {
188 irn_live = OALLOCNZ(&li->obst, be_lv_info_t, LV_STD_SIZE);
189 irn_live[0].head.n_size = LV_STD_SIZE-1;
190 ir_nodehashmap_insert(&li->map, bl, irn_live);
193 unsigned idx = get_irn_idx(irn);
195 /* Get the position of the index in the array. */
196 unsigned pos = _be_liveness_bsearch(irn_live, idx);
198 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
199 be_lv_info_node_t *res = &irn_live[pos + 1].node;
201 /* Check, if the irn is in deed in the array. */
202 if (res->idx != idx) {
203 be_lv_info_t *payload;
204 unsigned n_members = irn_live[0].head.n_members;
205 unsigned n_size = irn_live[0].head.n_size;
208 if (n_members + 1 >= n_size) {
209 /* double the array size. Remember that the first entry is
210 * metadata about the array and not a real array element */
211 unsigned old_size_bytes = (n_size + 1) * sizeof(irn_live[0]);
212 unsigned new_size = (2 * n_size) + 1;
213 size_t new_size_bytes = new_size * sizeof(irn_live[0]);
214 be_lv_info_t *nw = OALLOCN(&li->obst, be_lv_info_t, new_size);
215 memcpy(nw, irn_live, old_size_bytes);
216 memset(((char*) nw) + old_size_bytes, 0,
217 new_size_bytes - old_size_bytes);
218 nw[0].head.n_size = new_size - 1;
220 ir_nodehashmap_insert(&li->map, bl, nw);
223 payload = &irn_live[1];
224 for (i = n_members; i > pos; --i) {
225 payload[i] = payload[i - 1];
228 ++irn_live[0].head.n_members;
230 res = &payload[pos].node;
235 #ifdef LV_INTESIVE_CHECKS
238 unsigned n = irn_live[0].head.n_members;
240 be_lv_info_t *payload = &irn_live[1];
242 for (i = 0; i < n; ++i) {
243 assert(payload[i].node.idx >= last);
244 last = payload[i].node.idx;
253 * Removes a node from the list of live variables of a block.
254 * @return 1 if the node was live at that block, 0 if not.
256 static int be_lv_remove(be_lv_t *li, const ir_node *bl,
259 be_lv_info_t *irn_live = (be_lv_info_t*)ir_nodehashmap_get(&li->map, bl);
261 if (irn_live != NULL) {
262 unsigned n = irn_live[0].head.n_members;
263 unsigned idx = get_irn_idx(irn);
264 unsigned pos = _be_liveness_bsearch(irn_live, idx);
265 be_lv_info_t *payload = irn_live + 1;
266 be_lv_info_node_t *res = &payload[pos].node;
268 /* The node is in deed in the block's array. Let's remove it. */
269 if (res->idx == idx) {
272 for (i = pos + 1; i < n; ++i)
273 payload[i - 1] = payload[i];
275 payload[n - 1].node.idx = 0;
276 payload[n - 1].node.flags = 0;
278 --irn_live[0].head.n_members;
279 DBG((dbg, LEVEL_3, "\tdeleting %+F from %+F at pos %d\n", irn, bl, pos));
287 static void register_node(be_lv_t *lv, const ir_node *irn)
289 unsigned idx = get_irn_idx(irn);
290 if (idx >= bitset_size(lv->nodes)) {
291 bitset_t *nw = bitset_malloc(2 * idx);
292 bitset_copy_into(nw, lv->nodes);
293 bitset_free(lv->nodes);
297 bitset_set(lv->nodes, idx);
301 * Mark a node as live-in in a block.
303 static inline void mark_live_in(be_lv_t *lv, ir_node *block, ir_node *irn)
305 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
306 DBG((dbg, LEVEL_2, "marking %+F live in at %+F\n", irn, block));
307 n->flags |= be_lv_state_in;
308 register_node(lv, irn);
312 * Mark a node as live-out in a block.
314 static inline void mark_live_out(be_lv_t *lv, ir_node *block, ir_node *irn)
316 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
317 DBG((dbg, LEVEL_2, "marking %+F live out at %+F\n", irn, block));
318 n->flags |= be_lv_state_out | be_lv_state_end;
319 register_node(lv, irn);
323 * Mark a node as live-end in a block.
325 static inline void mark_live_end(be_lv_t *lv, ir_node *block, ir_node *irn)
327 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
328 DBG((dbg, LEVEL_2, "marking %+F live end at %+F\n", irn, block));
329 n->flags |= be_lv_state_end;
330 register_node(lv, irn);
334 be_lv_t *lv; /**< The liveness object. */
335 ir_node *def; /**< The node (value). */
336 ir_node *def_block; /**< The block of def. */
337 bitset_t *visited; /**< A set were all visited blocks are recorded. */
341 * Mark a node (value) live out at a certain block. Do this also
342 * transitively, i.e. if the block is not the block of the value's
343 * definition, all predecessors are also marked live.
344 * @param block The block to mark the value live out of.
345 * @param is_true_out Is the node real out there or only live at the end
348 static void live_end_at_block(ir_node *block, int is_true_out)
351 ir_node *def = re.def;
354 mark_live_end(lv, block, def);
356 mark_live_out(lv, block, def);
358 visited = re.visited;
359 if (!bitset_contains_irn(visited, block)) {
360 bitset_add_irn(visited, block);
363 * If this block is not the definition block, we have to go up
366 if (re.def_block != block) {
369 mark_live_in(lv, block, def);
371 for (i = get_Block_n_cfgpreds(block) - 1; i >= 0; --i)
372 live_end_at_block(get_Block_cfgpred_block(block, i), 1);
377 typedef struct lv_walker_t {
382 typedef struct lv_remove_walker_t {
385 } lv_remove_walker_t;
389 * Liveness analysis for a value.
390 * Compute the set of all blocks a value is live in.
391 * @param irn The node (value).
393 static void liveness_for_node(ir_node *irn)
395 const ir_edge_t *edge;
398 bitset_clear_all(re.visited);
399 def_block = get_nodes_block(irn);
402 re.def_block = def_block;
404 /* Go over all uses of the value */
405 foreach_out_edge(irn, edge) {
406 ir_node *use = edge->src;
409 DBG((dbg, LEVEL_4, "%+F: use at %+F, pos %d in %+F\n", irn, use, edge->pos, get_block(use)));
410 assert(get_irn_n(use, edge->pos) == irn);
413 * If the usage is no data node, skip this use, since it does not
414 * affect the liveness of the node.
416 if (!is_liveness_node(use))
419 /* Get the block where the usage is in. */
420 use_block = get_nodes_block(use);
423 * If the use is a phi function, determine the corresponding block
424 * through which the value reaches the phi function and mark the
425 * value as live out of that block.
428 ir_node *pred_block = get_Block_cfgpred_block(use_block, edge->pos);
429 live_end_at_block(pred_block, 0);
433 * Else, the value is live in at this block. Mark it and call live
434 * out on the predecessors.
436 else if (def_block != use_block) {
439 mark_live_in(re.lv, use_block, irn);
441 for (i = get_Block_n_cfgpreds(use_block) - 1; i >= 0; --i) {
442 ir_node *pred_block = get_Block_cfgpred_block(use_block, i);
443 live_end_at_block(pred_block, 1);
449 static void lv_remove_irn_walker(ir_node *bl, void *data)
451 lv_remove_walker_t *w = (lv_remove_walker_t*)data;
452 be_lv_remove(w->lv, bl, w->irn);
455 static const char *lv_flags_to_str(unsigned flags)
457 static const char *states[] = {
468 return states[flags & 7];
471 static void lv_dump_block(void *context, FILE *f, const ir_node *bl)
474 be_lv_t *lv = (be_lv_t*)context;
475 be_lv_info_t *info = (be_lv_info_t*)ir_nodehashmap_get(&lv->map, bl);
477 fprintf(f, "liveness:\n");
479 unsigned n = info[0].head.n_members;
482 for (i = 0; i < n; ++i) {
483 be_lv_info_node_t *n = &info[i+1].node;
484 ir_fprintf(f, "%s %+F\n", lv_flags_to_str(n->flags), get_idx_irn(lv->irg, n->idx));
491 * Walker, collect all nodes for which we want calculate liveness info
494 static void collect_liveness_nodes(ir_node *irn, void *data)
496 ir_node **nodes = (ir_node**)data;
497 if (is_liveness_node(irn))
498 nodes[get_irn_idx(irn)] = irn;
501 static void compute_liveness(be_lv_t *lv)
507 n = get_irg_last_idx(lv->irg);
508 nodes = NEW_ARR_F(ir_node *, n);
509 memset(nodes, 0, sizeof(nodes[0]) * n);
512 * inserting the variables sorted by their ID is probably
513 * more efficient since the binary sorted set insertion
514 * will not need to move around the data.
516 irg_walk_graph(lv->irg, NULL, collect_liveness_nodes, nodes);
519 re.visited = bitset_malloc(n);
521 for (i = 0; i < n; ++i) {
522 if (nodes[i] != NULL)
523 liveness_for_node(nodes[i]);
528 register_hook(hook_node_info, &lv->hook_info);
529 stat_ev_tim_pop("be_lv_sets_cons");
532 void be_liveness_assure_sets(be_lv_t *lv)
535 be_timer_push(T_LIVE);
537 lv->nodes = bitset_malloc(2 * get_irg_last_idx(lv->irg));
538 ir_nodehashmap_init(&lv->map);
539 obstack_init(&lv->obst);
540 compute_liveness(lv);
541 /* be_live_chk_compare(lv, lv->lvc); */
543 be_timer_pop(T_LIVE);
547 void be_liveness_assure_chk(be_lv_t *lv)
550 be_timer_push(t_verify);
551 be_liveness_assure_sets(lv);
552 be_timer_pop(t_verify);
558 void be_liveness_invalidate(be_lv_t *lv)
560 if (lv && lv->nodes) {
561 unregister_hook(hook_node_info, &lv->hook_info);
562 obstack_free(&lv->obst, NULL);
563 ir_nodehashmap_destroy(&lv->map);
564 bitset_free(lv->nodes);
569 /* Compute the inter block liveness for a graph. */
570 be_lv_t *be_liveness(ir_graph *irg)
572 be_lv_t *lv = XMALLOCZ(be_lv_t);
576 lv->dfs = dfs_new(&absgraph_irg_cfg_succ, irg);
577 lv->lvc = lv_chk_new(lv->irg, lv->dfs);
579 lv->hook_info.context = lv;
580 lv->hook_info.hook._hook_node_info = lv_dump_block;
585 void be_liveness_recompute(be_lv_t *lv)
589 be_timer_push(T_LIVE);
590 last_idx = get_irg_last_idx(lv->irg);
591 if (last_idx >= bitset_size(lv->nodes)) {
592 bitset_free(lv->nodes);
593 lv->nodes = bitset_malloc(last_idx * 2);
595 bitset_clear_all(lv->nodes);
597 ir_nodehashmap_destroy(&lv->map);
598 obstack_free(&lv->obst, NULL);
600 ir_nodehashmap_init(&lv->map);
601 obstack_init(&lv->obst);
602 compute_liveness(lv);
604 be_timer_pop(T_LIVE);
608 void be_liveness_free(be_lv_t *lv)
610 be_liveness_invalidate(lv);
612 lv_chk_free(lv->lvc);
618 void be_liveness_remove(be_lv_t *lv, const ir_node *irn)
621 unsigned idx = get_irn_idx(irn);
622 lv_remove_walker_t w;
625 * Removes a single irn from the liveness information.
626 * Since an irn can only be live at blocks dominated by the block of its
627 * definition, we only have to process that dominance subtree.
631 dom_tree_walk(get_nodes_block(irn), lv_remove_irn_walker, NULL, &w);
632 if (idx < bitset_size(lv->nodes))
633 bitset_clear(lv->nodes, idx);
637 void be_liveness_introduce(be_lv_t *lv, ir_node *irn)
639 /* Don't compute liveness information for non-data nodes. */
640 if (lv->nodes && is_liveness_node(irn)) {
642 re.visited = bitset_malloc(get_irg_last_idx(lv->irg));
643 liveness_for_node(irn);
644 bitset_free(re.visited);
648 void be_liveness_update(be_lv_t *lv, ir_node *irn)
650 be_liveness_remove(lv, irn);
651 be_liveness_introduce(lv, irn);
654 static void lv_check_walker(ir_node *bl, void *data)
656 lv_walker_t *w = (lv_walker_t*)data;
658 be_lv_t *fresh = (be_lv_t*)w->data;
660 be_lv_info_t *curr = (be_lv_info_t*)ir_nodehashmap_get(&fresh->map, bl);
661 be_lv_info_t *fr = (be_lv_info_t*)ir_nodehashmap_get(&fresh->map, bl);
663 if (!fr && curr && curr[0].head.n_members > 0) {
666 ir_fprintf(stderr, "%+F liveness should be empty but current liveness contains:\n", bl);
667 for (i = 0; i < curr[0].head.n_members; ++i) {
668 ir_fprintf(stderr, "\t%+F\n", get_idx_irn(lv->irg, curr[1 + i].node.idx));
673 unsigned n_curr = curr[0].head.n_members;
674 unsigned n_fresh = fr[0].head.n_members;
678 if (n_curr != n_fresh) {
679 ir_fprintf(stderr, "%+F: liveness set sizes differ. curr %d, correct %d\n", bl, n_curr, n_fresh);
681 ir_fprintf(stderr, "current:\n");
682 for (i = 0; i < n_curr; ++i) {
683 be_lv_info_node_t *n = &curr[1 + i].node;
684 ir_fprintf(stderr, "%+F %u %+F %s\n", bl, i, get_idx_irn(lv->irg, n->idx), lv_flags_to_str(n->flags));
687 ir_fprintf(stderr, "correct:\n");
688 for (i = 0; i < n_fresh; ++i) {
689 be_lv_info_node_t *n = &fr[1 + i].node;
690 ir_fprintf(stderr, "%+F %u %+F %s\n", bl, i, get_idx_irn(lv->irg, n->idx), lv_flags_to_str(n->flags));
696 void be_liveness_check(be_lv_t *lv)
699 be_lv_t *fresh = be_liveness(lv->irg);
703 irg_block_walk_graph(lv->irg, lv_check_walker, NULL, &w);
704 be_liveness_free(fresh);
708 static void lv_dump_block_walker(ir_node *irn, void *data)
710 lv_walker_t *w = (lv_walker_t*)data;
712 lv_dump_block(w->lv, (FILE*)w->data, irn);
716 /* Dump the liveness information for a graph. */
717 void be_liveness_dump(const be_lv_t *lv, FILE *f)
721 w.lv = (be_lv_t *) lv;
723 irg_block_walk_graph(lv->irg, lv_dump_block_walker, NULL, &w);
726 /* Dump the liveness information for a graph. */
727 void be_liveness_dumpto(const be_lv_t *lv, const char *cls_name)
731 ir_snprintf(buf, sizeof(buf), "%F_%s-live.txt", lv->irg, cls_name);
732 if ((f = fopen(buf, "wt")) != NULL) {
733 be_liveness_dump(lv, f);
739 * Walker: checks that every predecessors of a node dominates the node.
741 static void dom_check(ir_node *irn, void *data)
743 int *problem_found = (int*)data;
745 if (!is_Block(irn) && irn != get_irg_end(get_irn_irg(irn))) {
747 ir_node *bl = get_nodes_block(irn);
749 for (i = 0, n = get_irn_arity(irn); i < n; ++i) {
750 ir_node *op = get_irn_n(irn, i);
751 ir_node *def_bl = get_nodes_block(op);
752 ir_node *use_bl = bl;
755 use_bl = get_Block_cfgpred_block(bl, i);
757 if (get_irn_opcode(use_bl) != iro_Bad
758 && get_irn_opcode(def_bl) != iro_Bad
759 && !block_dominates(def_bl, use_bl)) {
760 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)));
767 /* Check, if the SSA dominance property is fulfilled. */
768 int be_check_dominance(ir_graph *irg)
770 int problem_found = 0;
773 irg_walk_graph(irg, dom_check, NULL, &problem_found);
775 return !problem_found;
778 void be_liveness_transfer(const arch_register_class_t *cls,
779 ir_node *node, ir_nodeset_t *nodeset)
783 /* You should better break out of your loop when hitting the first phi
785 assert(!is_Phi(node) && "liveness_transfer produces invalid results for phi nodes");
787 if (get_irn_mode(node) == mode_T) {
788 const ir_edge_t *edge;
790 foreach_out_edge(node, edge) {
791 ir_node *proj = get_edge_src_irn(edge);
793 if (arch_irn_consider_in_reg_alloc(cls, proj)) {
794 ir_nodeset_remove(nodeset, proj);
797 } else if (arch_irn_consider_in_reg_alloc(cls, node)) {
798 ir_nodeset_remove(nodeset, node);
801 arity = get_irn_arity(node);
802 for (i = 0; i < arity; ++i) {
803 ir_node *op = get_irn_n(node, i);
805 if (arch_irn_consider_in_reg_alloc(cls, op))
806 ir_nodeset_insert(nodeset, op);
812 void be_liveness_end_of_block(const be_lv_t *lv,
813 const arch_register_class_t *cls,
814 const ir_node *block, ir_nodeset_t *live)
818 assert(lv->nodes && "live sets must be computed");
819 be_lv_foreach(lv, block, be_lv_state_end, i) {
820 ir_node *node = be_lv_get_irn(lv, block, i);
821 if (!arch_irn_consider_in_reg_alloc(cls, node))
824 ir_nodeset_insert(live, node);
830 void be_liveness_nodes_live_at(const be_lv_t *lv,
831 const arch_register_class_t *cls,
832 const ir_node *pos, ir_nodeset_t *live)
834 const ir_node *bl = is_Block(pos) ? pos : get_nodes_block(pos);
837 be_liveness_end_of_block(lv, cls, bl, live);
838 sched_foreach_reverse(bl, irn) {
840 * If we encounter the node we want to insert the Perm after,
841 * exit immediately, so that this node is still live
846 be_liveness_transfer(cls, irn, live);
850 static void collect_node(ir_node *irn, void *data)
852 struct obstack *obst = (struct obstack*)data;
853 obstack_ptr_grow(obst, irn);
856 void be_live_chk_compare(be_lv_t *lv, lv_chk_t *lvc)
858 ir_graph *irg = lv->irg;
867 irg_block_walk_graph(irg, collect_node, NULL, &obst);
868 obstack_ptr_grow(&obst, NULL);
869 blocks = (ir_node**)obstack_finish(&obst);
871 irg_walk_graph(irg, collect_node, NULL, &obst);
872 obstack_ptr_grow(&obst, NULL);
873 nodes = (ir_node**)obstack_finish(&obst);
875 stat_ev_ctx_push("be_lv_chk_compare");
876 for (j = 0; nodes[j]; ++j) {
877 ir_node *irn = nodes[j];
881 for (i = 0; blocks[i]; ++i) {
882 ir_node *bl = blocks[i];
883 int lvr_in = be_is_live_in (lv, bl, irn);
884 int lvr_out = be_is_live_out(lv, bl, irn);
885 int lvr_end = be_is_live_end(lv, bl, irn);
887 int lvc_in = lv_chk_bl_in (lvc, bl, irn);
888 int lvc_out = lv_chk_bl_out(lvc, bl, irn);
889 int lvc_end = lv_chk_bl_end(lvc, bl, irn);
891 if (lvr_in - lvc_in != 0)
892 ir_fprintf(stderr, "live in info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_in, lvc_in);
894 if (lvr_end - lvc_end != 0)
895 ir_fprintf(stderr, "live end info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_end, lvc_end);
897 if (lvr_out - lvc_out != 0)
898 ir_fprintf(stderr, "live out info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_out, lvc_out);
901 stat_ev_ctx_pop("be_lv_chk_compare");
903 obstack_free(&obst, NULL);
906 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_live)
907 void be_init_live(void)
909 FIRM_DBG_REGISTER(dbg, "firm.be.liveness");