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"
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_is_set(visited, get_irn_idx(block))) {
360 bitset_set(visited, get_irn_idx(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_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 = (lv_remove_walker_t*)data;
447 be_lv_remove(w->lv, bl, w->irn);
451 * Walker, collect all nodes for which we want calculate liveness info
454 static void collect_liveness_nodes(ir_node *irn, void *data)
456 ir_node **nodes = (ir_node**)data;
457 if (is_liveness_node(irn))
458 nodes[get_irn_idx(irn)] = irn;
461 static void compute_liveness(be_lv_t *lv)
467 n = get_irg_last_idx(lv->irg);
468 nodes = NEW_ARR_F(ir_node *, n);
469 memset(nodes, 0, sizeof(nodes[0]) * n);
472 * inserting the variables sorted by their ID is probably
473 * more efficient since the binary sorted set insertion
474 * will not need to move around the data.
476 irg_walk_graph(lv->irg, NULL, collect_liveness_nodes, nodes);
479 re.visited = bitset_malloc(n);
481 for (i = 0; i < n; ++i) {
482 if (nodes[i] != NULL)
483 liveness_for_node(nodes[i]);
488 register_hook(hook_node_info, &lv->hook_info);
489 stat_ev_tim_pop("be_lv_sets_cons");
492 void be_liveness_assure_sets(be_lv_t *lv)
495 be_timer_push(T_LIVE);
497 lv->nodes = bitset_malloc(2 * get_irg_last_idx(lv->irg));
498 ir_nodehashmap_init(&lv->map);
499 obstack_init(&lv->obst);
500 compute_liveness(lv);
501 /* be_live_chk_compare(lv, lv->lvc); */
503 be_timer_pop(T_LIVE);
507 void be_liveness_assure_chk(be_lv_t *lv)
510 be_timer_push(t_verify);
511 be_liveness_assure_sets(lv);
512 be_timer_pop(t_verify);
518 void be_liveness_invalidate(be_lv_t *lv)
520 if (lv && lv->nodes) {
521 unregister_hook(hook_node_info, &lv->hook_info);
522 obstack_free(&lv->obst, NULL);
523 ir_nodehashmap_destroy(&lv->map);
524 bitset_free(lv->nodes);
529 /* Compute the inter block liveness for a graph. */
530 be_lv_t *be_liveness(ir_graph *irg)
532 be_lv_t *lv = XMALLOCZ(be_lv_t);
536 lv->dfs = dfs_new(&absgraph_irg_cfg_succ, irg);
537 lv->lvc = lv_chk_new(lv->irg, lv->dfs);
539 lv->hook_info.context = lv;
540 lv->hook_info.hook._hook_node_info = be_dump_liveness_block;
545 void be_liveness_recompute(be_lv_t *lv)
549 be_timer_push(T_LIVE);
550 last_idx = get_irg_last_idx(lv->irg);
551 if (last_idx >= bitset_size(lv->nodes)) {
552 bitset_free(lv->nodes);
553 lv->nodes = bitset_malloc(last_idx * 2);
555 bitset_clear_all(lv->nodes);
557 ir_nodehashmap_destroy(&lv->map);
558 obstack_free(&lv->obst, NULL);
560 ir_nodehashmap_init(&lv->map);
561 obstack_init(&lv->obst);
562 compute_liveness(lv);
564 be_timer_pop(T_LIVE);
568 void be_liveness_free(be_lv_t *lv)
570 be_liveness_invalidate(lv);
572 lv_chk_free(lv->lvc);
578 void be_liveness_remove(be_lv_t *lv, const ir_node *irn)
581 unsigned idx = get_irn_idx(irn);
582 lv_remove_walker_t w;
585 * Removes a single irn from the liveness information.
586 * Since an irn can only be live at blocks dominated by the block of its
587 * definition, we only have to process that dominance subtree.
591 dom_tree_walk(get_nodes_block(irn), lv_remove_irn_walker, NULL, &w);
592 if (idx < bitset_size(lv->nodes))
593 bitset_clear(lv->nodes, idx);
597 void be_liveness_introduce(be_lv_t *lv, ir_node *irn)
599 /* Don't compute liveness information for non-data nodes. */
600 if (lv->nodes && is_liveness_node(irn)) {
602 re.visited = bitset_malloc(get_irg_last_idx(lv->irg));
603 liveness_for_node(irn);
604 bitset_free(re.visited);
608 void be_liveness_update(be_lv_t *lv, ir_node *irn)
610 be_liveness_remove(lv, irn);
611 be_liveness_introduce(lv, irn);
614 void be_liveness_transfer(const arch_register_class_t *cls,
615 ir_node *node, ir_nodeset_t *nodeset)
619 /* You should better break out of your loop when hitting the first phi
621 assert(!is_Phi(node) && "liveness_transfer produces invalid results for phi nodes");
623 if (get_irn_mode(node) == mode_T) {
624 const ir_edge_t *edge;
626 foreach_out_edge(node, edge) {
627 ir_node *proj = get_edge_src_irn(edge);
629 if (arch_irn_consider_in_reg_alloc(cls, proj)) {
630 ir_nodeset_remove(nodeset, proj);
633 } else if (arch_irn_consider_in_reg_alloc(cls, node)) {
634 ir_nodeset_remove(nodeset, node);
637 arity = get_irn_arity(node);
638 for (i = 0; i < arity; ++i) {
639 ir_node *op = get_irn_n(node, i);
641 if (arch_irn_consider_in_reg_alloc(cls, op))
642 ir_nodeset_insert(nodeset, op);
648 void be_liveness_end_of_block(const be_lv_t *lv,
649 const arch_register_class_t *cls,
650 const ir_node *block, ir_nodeset_t *live)
654 assert(lv->nodes && "live sets must be computed");
655 be_lv_foreach(lv, block, be_lv_state_end, i) {
656 ir_node *node = be_lv_get_irn(lv, block, i);
657 if (!arch_irn_consider_in_reg_alloc(cls, node))
660 ir_nodeset_insert(live, node);
666 void be_liveness_nodes_live_at(const be_lv_t *lv,
667 const arch_register_class_t *cls,
668 const ir_node *pos, ir_nodeset_t *live)
670 const ir_node *bl = is_Block(pos) ? pos : get_nodes_block(pos);
673 be_liveness_end_of_block(lv, cls, bl, live);
674 sched_foreach_reverse(bl, irn) {
676 * If we encounter the node we want to insert the Perm after,
677 * exit immediately, so that this node is still live
682 be_liveness_transfer(cls, irn, live);
686 static void collect_node(ir_node *irn, void *data)
688 struct obstack *obst = (struct obstack*)data;
689 obstack_ptr_grow(obst, irn);
692 void be_live_chk_compare(be_lv_t *lv, lv_chk_t *lvc)
694 ir_graph *irg = lv->irg;
703 irg_block_walk_graph(irg, collect_node, NULL, &obst);
704 obstack_ptr_grow(&obst, NULL);
705 blocks = (ir_node**)obstack_finish(&obst);
707 irg_walk_graph(irg, collect_node, NULL, &obst);
708 obstack_ptr_grow(&obst, NULL);
709 nodes = (ir_node**)obstack_finish(&obst);
711 stat_ev_ctx_push("be_lv_chk_compare");
712 for (j = 0; nodes[j]; ++j) {
713 ir_node *irn = nodes[j];
717 for (i = 0; blocks[i]; ++i) {
718 ir_node *bl = blocks[i];
719 int lvr_in = be_is_live_in (lv, bl, irn);
720 int lvr_out = be_is_live_out(lv, bl, irn);
721 int lvr_end = be_is_live_end(lv, bl, irn);
723 int lvc_in = lv_chk_bl_in (lvc, bl, irn);
724 int lvc_out = lv_chk_bl_out(lvc, bl, irn);
725 int lvc_end = lv_chk_bl_end(lvc, bl, irn);
727 if (lvr_in - lvc_in != 0)
728 ir_fprintf(stderr, "live in info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_in, lvc_in);
730 if (lvr_end - lvc_end != 0)
731 ir_fprintf(stderr, "live end info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_end, lvc_end);
733 if (lvr_out - lvc_out != 0)
734 ir_fprintf(stderr, "live out info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_out, lvc_out);
737 stat_ev_ctx_pop("be_lv_chk_compare");
739 obstack_free(&obst, NULL);
742 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_live)
743 void be_init_live(void)
745 FIRM_DBG_REGISTER(dbg, "firm.be.liveness");