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_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);
450 * Walker, collect all nodes for which we want calculate liveness info
453 static void collect_liveness_nodes(ir_node *irn, void *data)
455 ir_node **nodes = (ir_node**)data;
456 if (is_liveness_node(irn))
457 nodes[get_irn_idx(irn)] = irn;
460 static void compute_liveness(be_lv_t *lv)
466 n = get_irg_last_idx(lv->irg);
467 nodes = NEW_ARR_F(ir_node *, n);
468 memset(nodes, 0, sizeof(nodes[0]) * n);
471 * inserting the variables sorted by their ID is probably
472 * more efficient since the binary sorted set insertion
473 * will not need to move around the data.
475 irg_walk_graph(lv->irg, NULL, collect_liveness_nodes, nodes);
478 re.visited = bitset_malloc(n);
480 for (i = 0; i < n; ++i) {
481 if (nodes[i] != NULL)
482 liveness_for_node(nodes[i]);
487 register_hook(hook_node_info, &lv->hook_info);
488 stat_ev_tim_pop("be_lv_sets_cons");
491 void be_liveness_assure_sets(be_lv_t *lv)
494 be_timer_push(T_LIVE);
496 lv->nodes = bitset_malloc(2 * get_irg_last_idx(lv->irg));
497 ir_nodehashmap_init(&lv->map);
498 obstack_init(&lv->obst);
499 compute_liveness(lv);
500 /* be_live_chk_compare(lv, lv->lvc); */
502 be_timer_pop(T_LIVE);
506 void be_liveness_assure_chk(be_lv_t *lv)
509 be_timer_push(t_verify);
510 be_liveness_assure_sets(lv);
511 be_timer_pop(t_verify);
517 void be_liveness_invalidate(be_lv_t *lv)
519 if (lv && lv->nodes) {
520 unregister_hook(hook_node_info, &lv->hook_info);
521 obstack_free(&lv->obst, NULL);
522 ir_nodehashmap_destroy(&lv->map);
523 bitset_free(lv->nodes);
528 /* Compute the inter block liveness for a graph. */
529 be_lv_t *be_liveness(ir_graph *irg)
531 be_lv_t *lv = XMALLOCZ(be_lv_t);
535 lv->lvc = lv_chk_new(lv->irg);
537 lv->hook_info.context = lv;
538 lv->hook_info.hook._hook_node_info = be_dump_liveness_block;
543 void be_liveness_recompute(be_lv_t *lv)
547 be_timer_push(T_LIVE);
548 last_idx = get_irg_last_idx(lv->irg);
549 if (last_idx >= bitset_size(lv->nodes)) {
550 bitset_free(lv->nodes);
551 lv->nodes = bitset_malloc(last_idx * 2);
553 bitset_clear_all(lv->nodes);
555 ir_nodehashmap_destroy(&lv->map);
556 obstack_free(&lv->obst, NULL);
558 ir_nodehashmap_init(&lv->map);
559 obstack_init(&lv->obst);
560 compute_liveness(lv);
562 be_timer_pop(T_LIVE);
566 void be_liveness_free(be_lv_t *lv)
568 be_liveness_invalidate(lv);
570 lv_chk_free(lv->lvc);
575 void be_liveness_remove(be_lv_t *lv, const ir_node *irn)
578 unsigned idx = get_irn_idx(irn);
579 lv_remove_walker_t w;
582 * Removes a single irn from the liveness information.
583 * Since an irn can only be live at blocks dominated by the block of its
584 * definition, we only have to process that dominance subtree.
588 dom_tree_walk(get_nodes_block(irn), lv_remove_irn_walker, NULL, &w);
589 if (idx < bitset_size(lv->nodes))
590 bitset_clear(lv->nodes, idx);
594 void be_liveness_introduce(be_lv_t *lv, ir_node *irn)
596 /* Don't compute liveness information for non-data nodes. */
597 if (lv->nodes && is_liveness_node(irn)) {
599 re.visited = bitset_malloc(get_irg_last_idx(lv->irg));
600 liveness_for_node(irn);
601 bitset_free(re.visited);
605 void be_liveness_update(be_lv_t *lv, ir_node *irn)
607 be_liveness_remove(lv, irn);
608 be_liveness_introduce(lv, irn);
611 void be_liveness_transfer(const arch_register_class_t *cls,
612 ir_node *node, ir_nodeset_t *nodeset)
616 /* You should better break out of your loop when hitting the first phi
618 assert(!is_Phi(node) && "liveness_transfer produces invalid results for phi nodes");
620 if (get_irn_mode(node) == mode_T) {
621 const ir_edge_t *edge;
623 foreach_out_edge(node, edge) {
624 ir_node *proj = get_edge_src_irn(edge);
626 if (arch_irn_consider_in_reg_alloc(cls, proj)) {
627 ir_nodeset_remove(nodeset, proj);
630 } else if (arch_irn_consider_in_reg_alloc(cls, node)) {
631 ir_nodeset_remove(nodeset, node);
634 arity = get_irn_arity(node);
635 for (i = 0; i < arity; ++i) {
636 ir_node *op = get_irn_n(node, i);
638 if (arch_irn_consider_in_reg_alloc(cls, op))
639 ir_nodeset_insert(nodeset, op);
645 void be_liveness_end_of_block(const be_lv_t *lv,
646 const arch_register_class_t *cls,
647 const ir_node *block, ir_nodeset_t *live)
651 assert(lv->nodes && "live sets must be computed");
652 be_lv_foreach(lv, block, be_lv_state_end, i) {
653 ir_node *node = be_lv_get_irn(lv, block, i);
654 if (!arch_irn_consider_in_reg_alloc(cls, node))
657 ir_nodeset_insert(live, node);
663 void be_liveness_nodes_live_at(const be_lv_t *lv,
664 const arch_register_class_t *cls,
665 const ir_node *pos, ir_nodeset_t *live)
667 const ir_node *bl = is_Block(pos) ? pos : get_nodes_block(pos);
670 be_liveness_end_of_block(lv, cls, bl, live);
671 sched_foreach_reverse(bl, irn) {
673 * If we encounter the node we want to insert the Perm after,
674 * exit immediately, so that this node is still live
679 be_liveness_transfer(cls, irn, live);
683 static void collect_node(ir_node *irn, void *data)
685 struct obstack *obst = (struct obstack*)data;
686 obstack_ptr_grow(obst, irn);
689 void be_live_chk_compare(be_lv_t *lv, lv_chk_t *lvc)
691 ir_graph *irg = lv->irg;
700 irg_block_walk_graph(irg, collect_node, NULL, &obst);
701 obstack_ptr_grow(&obst, NULL);
702 blocks = (ir_node**)obstack_finish(&obst);
704 irg_walk_graph(irg, collect_node, NULL, &obst);
705 obstack_ptr_grow(&obst, NULL);
706 nodes = (ir_node**)obstack_finish(&obst);
708 stat_ev_ctx_push("be_lv_chk_compare");
709 for (j = 0; nodes[j]; ++j) {
710 ir_node *irn = nodes[j];
714 for (i = 0; blocks[i]; ++i) {
715 ir_node *bl = blocks[i];
716 int lvr_in = be_is_live_in (lv, bl, irn);
717 int lvr_out = be_is_live_out(lv, bl, irn);
718 int lvr_end = be_is_live_end(lv, bl, irn);
720 int lvc_in = lv_chk_bl_in (lvc, bl, irn);
721 int lvc_out = lv_chk_bl_out(lvc, bl, irn);
722 int lvc_end = lv_chk_bl_end(lvc, bl, irn);
724 if (lvr_in - lvc_in != 0)
725 ir_fprintf(stderr, "live in info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_in, lvc_in);
727 if (lvr_end - lvc_end != 0)
728 ir_fprintf(stderr, "live end info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_end, lvc_end);
730 if (lvr_out - lvc_out != 0)
731 ir_fprintf(stderr, "live out info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_out, lvc_out);
734 stat_ev_ctx_pop("be_lv_chk_compare");
736 obstack_free(&obst, NULL);
739 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_live)
740 void be_init_live(void)
742 FIRM_DBG_REGISTER(dbg, "firm.be.liveness");