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"
35 #include "irnodeset.h"
47 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
49 #define LV_STD_SIZE 64
52 * Filter out some nodes for which we never need liveness.
54 * @param irn the node t check
55 * @return 0 if no liveness info is needed, 1 else
57 static inline int is_liveness_node(const ir_node *irn)
59 switch (get_irn_opcode(irn)) {
71 int (be_is_live_in)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
73 return _be_is_live_xxx(lv, block, irn, be_lv_state_in);
76 int (be_is_live_out)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
78 return _be_is_live_xxx(lv, block, irn, be_lv_state_out);
81 int (be_is_live_end)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
83 return _be_is_live_xxx(lv, block, irn, be_lv_state_end);
86 static inline unsigned _be_liveness_bsearch(be_lv_info_t *arr, const ir_node *node)
88 be_lv_info_t *payload = arr + 1;
90 unsigned n = arr[0].head.n_members;
99 int md = lo + ((hi - lo) >> 1);
100 ir_node *md_node = payload[md].node.node;
104 else if (node < md_node)
117 be_lv_info_node_t *be_lv_get(const be_lv_t *li, const ir_node *bl,
120 be_lv_info_t *irn_live;
121 be_lv_info_node_t *res = NULL;
124 irn_live = ir_nodehashmap_get(be_lv_info_t, &li->map, bl);
125 if (irn_live != NULL) {
126 /* Get the position of the index in the array. */
127 int pos = _be_liveness_bsearch(irn_live, irn);
129 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
130 be_lv_info_node_t *rec = &irn_live[pos + 1].node;
132 /* Check, if the irn is in deed in the array. */
133 if (rec->node == irn)
136 stat_ev_tim_pop("be_lv_get");
141 static be_lv_info_node_t *be_lv_get_or_set(be_lv_t *li, ir_node *bl,
144 be_lv_info_t *irn_live = ir_nodehashmap_get(be_lv_info_t, &li->map, bl);
145 if (irn_live == NULL) {
146 irn_live = OALLOCNZ(&li->obst, be_lv_info_t, LV_STD_SIZE);
147 irn_live[0].head.n_size = LV_STD_SIZE-1;
148 ir_nodehashmap_insert(&li->map, bl, irn_live);
151 /* Get the position of the index in the array. */
152 unsigned pos = _be_liveness_bsearch(irn_live, irn);
154 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
155 be_lv_info_node_t *res = &irn_live[pos + 1].node;
157 /* Check, if the irn is in deed in the array. */
158 if (res->node != irn) {
159 be_lv_info_t *payload;
160 unsigned n_members = irn_live[0].head.n_members;
161 unsigned n_size = irn_live[0].head.n_size;
164 if (n_members + 1 >= n_size) {
165 /* double the array size. Remember that the first entry is
166 * metadata about the array and not a real array element */
167 unsigned old_size_bytes = (n_size + 1) * sizeof(irn_live[0]);
168 unsigned new_size = (2 * n_size) + 1;
169 size_t new_size_bytes = new_size * sizeof(irn_live[0]);
170 be_lv_info_t *nw = OALLOCN(&li->obst, be_lv_info_t, new_size);
171 memcpy(nw, irn_live, old_size_bytes);
172 memset(((char*) nw) + old_size_bytes, 0,
173 new_size_bytes - old_size_bytes);
174 nw[0].head.n_size = new_size - 1;
176 ir_nodehashmap_insert(&li->map, bl, nw);
179 payload = &irn_live[1];
180 for (i = n_members; i > pos; --i) {
181 payload[i] = payload[i - 1];
184 ++irn_live[0].head.n_members;
186 res = &payload[pos].node;
195 * Removes a node from the list of live variables of a block.
196 * @return 1 if the node was live at that block, 0 if not.
198 static int be_lv_remove(be_lv_t *li, const ir_node *bl,
201 be_lv_info_t *irn_live = ir_nodehashmap_get(be_lv_info_t, &li->map, bl);
203 if (irn_live != NULL) {
204 unsigned n = irn_live[0].head.n_members;
205 unsigned pos = _be_liveness_bsearch(irn_live, irn);
206 be_lv_info_t *payload = irn_live + 1;
207 be_lv_info_node_t *res = &payload[pos].node;
209 /* The node is in deed in the block's array. Let's remove it. */
210 if (res->node == irn) {
213 for (i = pos + 1; i < n; ++i)
214 payload[i - 1] = payload[i];
216 payload[n - 1].node.node = NULL;
217 payload[n - 1].node.flags = 0;
219 --irn_live[0].head.n_members;
220 DBG((dbg, LEVEL_3, "\tdeleting %+F from %+F at pos %d\n", irn, bl, pos));
229 * Mark a node as live-in in a block.
231 static inline void mark_live_in(be_lv_t *lv, ir_node *block, ir_node *irn)
233 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
234 DBG((dbg, LEVEL_2, "marking %+F live in at %+F\n", irn, block));
235 n->flags |= be_lv_state_in;
239 * Mark a node as live-out in a block.
241 static inline void mark_live_out(be_lv_t *lv, ir_node *block, ir_node *irn)
243 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
244 DBG((dbg, LEVEL_2, "marking %+F live out at %+F\n", irn, block));
245 n->flags |= be_lv_state_out | be_lv_state_end;
249 * Mark a node as live-end in a block.
251 static inline void mark_live_end(be_lv_t *lv, ir_node *block, ir_node *irn)
253 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
254 DBG((dbg, LEVEL_2, "marking %+F live end at %+F\n", irn, block));
255 n->flags |= be_lv_state_end;
259 be_lv_t *lv; /**< The liveness object. */
260 ir_node *def; /**< The node (value). */
261 ir_node *def_block; /**< The block of def. */
262 bitset_t *visited; /**< A set were all visited blocks are recorded. */
266 * Mark a node (value) live out at a certain block. Do this also
267 * transitively, i.e. if the block is not the block of the value's
268 * definition, all predecessors are also marked live.
269 * @param block The block to mark the value live out of.
270 * @param is_true_out Is the node real out there or only live at the end
273 static void live_end_at_block(ir_node *block, int is_true_out)
276 ir_node *def = re.def;
279 mark_live_end(lv, block, def);
281 mark_live_out(lv, block, def);
283 visited = re.visited;
284 if (!bitset_is_set(visited, get_irn_idx(block))) {
285 bitset_set(visited, get_irn_idx(block));
288 * If this block is not the definition block, we have to go up
291 if (re.def_block != block) {
294 mark_live_in(lv, block, def);
296 for (i = get_Block_n_cfgpreds(block) - 1; i >= 0; --i)
297 live_end_at_block(get_Block_cfgpred_block(block, i), 1);
302 typedef struct lv_remove_walker_t {
305 } lv_remove_walker_t;
309 * Liveness analysis for a value.
310 * Compute the set of all blocks a value is live in.
311 * @param irn The node (value).
313 static void liveness_for_node(ir_node *irn)
317 bitset_clear_all(re.visited);
318 def_block = get_nodes_block(irn);
321 re.def_block = def_block;
323 /* Go over all uses of the value */
324 foreach_out_edge(irn, edge) {
325 ir_node *use = edge->src;
328 DBG((dbg, LEVEL_4, "%+F: use at %+F, pos %d in %+F\n", irn, use, edge->pos, get_block(use)));
329 assert(get_irn_n(use, edge->pos) == irn);
332 * If the usage is no data node, skip this use, since it does not
333 * affect the liveness of the node.
335 if (!is_liveness_node(use))
338 /* Get the block where the usage is in. */
339 use_block = get_nodes_block(use);
342 * If the use is a phi function, determine the corresponding block
343 * through which the value reaches the phi function and mark the
344 * value as live out of that block.
347 ir_node *pred_block = get_Block_cfgpred_block(use_block, edge->pos);
348 live_end_at_block(pred_block, 0);
352 * Else, the value is live in at this block. Mark it and call live
353 * out on the predecessors.
355 else if (def_block != use_block) {
358 mark_live_in(re.lv, use_block, irn);
360 for (i = get_Block_n_cfgpreds(use_block) - 1; i >= 0; --i) {
361 ir_node *pred_block = get_Block_cfgpred_block(use_block, i);
362 live_end_at_block(pred_block, 1);
368 static void lv_remove_irn_walker(ir_node *bl, void *data)
370 lv_remove_walker_t *w = (lv_remove_walker_t*)data;
371 be_lv_remove(w->lv, bl, w->irn);
375 * Walker, collect all nodes for which we want calculate liveness info
378 static void collect_liveness_nodes(ir_node *irn, void *data)
380 ir_node **nodes = (ir_node**)data;
381 if (is_liveness_node(irn))
382 nodes[get_irn_idx(irn)] = irn;
385 void be_liveness_compute_sets(be_lv_t *lv)
394 be_timer_push(T_LIVE);
395 ir_nodehashmap_init(&lv->map);
396 obstack_init(&lv->obst);
398 n = get_irg_last_idx(lv->irg);
399 nodes = NEW_ARR_F(ir_node *, n);
400 memset(nodes, 0, sizeof(nodes[0]) * n);
402 /* inserting the variables sorted by their ID is probably
403 * more efficient since the binary sorted set insertion
404 * will not need to move around the data. */
405 irg_walk_graph(lv->irg, NULL, collect_liveness_nodes, nodes);
408 re.visited = bitset_malloc(n);
410 for (i = 0; i < n; ++i) {
411 if (nodes[i] != NULL)
412 liveness_for_node(nodes[i]);
417 register_hook(hook_node_info, &lv->hook_info);
419 be_timer_pop(T_LIVE);
421 lv->sets_valid = true;
424 void be_liveness_compute_chk(be_lv_t *lv)
428 lv->lvc = lv_chk_new(lv->irg);
431 void be_liveness_invalidate_sets(be_lv_t *lv)
435 unregister_hook(hook_node_info, &lv->hook_info);
436 obstack_free(&lv->obst, NULL);
437 ir_nodehashmap_destroy(&lv->map);
438 lv->sets_valid = false;
441 void be_liveness_invalidate_chk(be_lv_t *lv)
443 be_liveness_invalidate_sets(lv);
447 lv_chk_free(lv->lvc);
451 be_lv_t *be_liveness_new(ir_graph *irg)
453 be_lv_t *lv = XMALLOCZ(be_lv_t);
456 lv->hook_info.context = lv;
457 lv->hook_info.hook._hook_node_info = be_dump_liveness_block;
462 void be_liveness_free(be_lv_t *lv)
464 be_liveness_invalidate_sets(lv);
465 be_liveness_invalidate_chk(lv);
470 void be_liveness_remove(be_lv_t *lv, const ir_node *irn)
472 if (lv->sets_valid) {
473 lv_remove_walker_t w;
476 * Removes a single irn from the liveness information.
477 * Since an irn can only be live at blocks dominated by the block of its
478 * definition, we only have to process that dominance subtree.
482 dom_tree_walk(get_nodes_block(irn), lv_remove_irn_walker, NULL, &w);
486 void be_liveness_introduce(be_lv_t *lv, ir_node *irn)
488 /* Don't compute liveness information for non-data nodes. */
489 if (lv->sets_valid && is_liveness_node(irn)) {
491 re.visited = bitset_malloc(get_irg_last_idx(lv->irg));
492 liveness_for_node(irn);
493 bitset_free(re.visited);
497 void be_liveness_update(be_lv_t *lv, ir_node *irn)
499 be_liveness_remove(lv, irn);
500 be_liveness_introduce(lv, irn);
503 void be_liveness_transfer(const arch_register_class_t *cls,
504 ir_node *node, ir_nodeset_t *nodeset)
506 /* You should better break out of your loop when hitting the first phi
508 assert(!is_Phi(node) && "liveness_transfer produces invalid results for phi nodes");
510 be_foreach_definition(node, cls, value,
511 ir_nodeset_remove(nodeset, value);
514 int arity = get_irn_arity(node);
515 for (int i = 0; i < arity; ++i) {
516 const arch_register_req_t *in_req = arch_get_irn_register_req_in(node, i);
517 if (in_req->cls != cls)
519 ir_node *op = get_irn_n(node, i);
520 const arch_register_req_t *op_req = arch_get_irn_register_req(op);
521 if (arch_register_req_is(op_req, ignore))
523 ir_nodeset_insert(nodeset, op);
529 void be_liveness_end_of_block(const be_lv_t *lv,
530 const arch_register_class_t *cls,
531 const ir_node *block, ir_nodeset_t *live)
533 assert(lv->sets_valid && "live sets must be computed");
534 be_lv_foreach(lv, block, be_lv_state_end, node) {
535 if (!arch_irn_consider_in_reg_alloc(cls, node))
538 ir_nodeset_insert(live, node);
544 void be_liveness_nodes_live_before(be_lv_t const *const lv, arch_register_class_t const *const cls, ir_node const *const pos, ir_nodeset_t *const live)
546 ir_node const *const bl = get_nodes_block(pos);
547 be_liveness_end_of_block(lv, cls, bl, live);
548 sched_foreach_reverse(bl, irn) {
549 be_liveness_transfer(cls, irn, live);
555 static void collect_node(ir_node *irn, void *data)
557 struct obstack *obst = (struct obstack*)data;
558 obstack_ptr_grow(obst, irn);
561 static void be_live_chk_compare(be_lv_t *lv, lv_chk_t *lvc)
563 ir_graph *irg = lv->irg;
572 irg_block_walk_graph(irg, collect_node, NULL, &obst);
573 obstack_ptr_grow(&obst, NULL);
574 blocks = (ir_node**)obstack_finish(&obst);
576 irg_walk_graph(irg, collect_node, NULL, &obst);
577 obstack_ptr_grow(&obst, NULL);
578 nodes = (ir_node**)obstack_finish(&obst);
580 stat_ev_ctx_push("be_lv_chk_compare");
581 for (j = 0; nodes[j]; ++j) {
582 ir_node *irn = nodes[j];
586 for (i = 0; blocks[i]; ++i) {
587 ir_node *bl = blocks[i];
588 int lvr_in = be_is_live_in (lv, bl, irn);
589 int lvr_out = be_is_live_out(lv, bl, irn);
590 int lvr_end = be_is_live_end(lv, bl, irn);
592 int lvc_in = lv_chk_bl_in (lvc, bl, irn);
593 int lvc_out = lv_chk_bl_out(lvc, bl, irn);
594 int lvc_end = lv_chk_bl_end(lvc, bl, irn);
596 if (lvr_in - lvc_in != 0)
597 ir_fprintf(stderr, "live in info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_in, lvc_in);
599 if (lvr_end - lvc_end != 0)
600 ir_fprintf(stderr, "live end info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_end, lvc_end);
602 if (lvr_out - lvc_out != 0)
603 ir_fprintf(stderr, "live out info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_out, lvc_out);
606 stat_ev_ctx_pop("be_lv_chk_compare");
608 obstack_free(&obst, NULL);
611 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_live)
612 void be_init_live(void)
614 (void)be_live_chk_compare;
615 FIRM_DBG_REGISTER(dbg, "firm.be.liveness");