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"
46 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
48 #define LV_STD_SIZE 64
50 int (be_is_live_in)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
52 return _be_is_live_xxx(lv, block, irn, be_lv_state_in);
55 int (be_is_live_out)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
57 return _be_is_live_xxx(lv, block, irn, be_lv_state_out);
60 int (be_is_live_end)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
62 return _be_is_live_xxx(lv, block, irn, be_lv_state_end);
65 static inline unsigned _be_liveness_bsearch(be_lv_info_t *arr, const ir_node *node)
67 be_lv_info_t *payload = arr + 1;
69 unsigned n = arr[0].head.n_members;
78 int md = lo + ((hi - lo) >> 1);
79 ir_node *md_node = payload[md].node.node;
83 else if (node < md_node)
96 be_lv_info_node_t *be_lv_get(const be_lv_t *li, const ir_node *bl,
99 be_lv_info_t *irn_live;
100 be_lv_info_node_t *res = NULL;
103 irn_live = ir_nodehashmap_get(be_lv_info_t, &li->map, bl);
104 if (irn_live != NULL) {
105 /* Get the position of the index in the array. */
106 int pos = _be_liveness_bsearch(irn_live, irn);
108 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
109 be_lv_info_node_t *rec = &irn_live[pos + 1].node;
111 /* Check, if the irn is in deed in the array. */
112 if (rec->node == irn)
115 stat_ev_tim_pop("be_lv_get");
120 static be_lv_info_node_t *be_lv_get_or_set(be_lv_t *li, ir_node *bl,
123 be_lv_info_t *irn_live = ir_nodehashmap_get(be_lv_info_t, &li->map, bl);
124 if (irn_live == NULL) {
125 irn_live = OALLOCNZ(&li->obst, be_lv_info_t, LV_STD_SIZE);
126 irn_live[0].head.n_size = LV_STD_SIZE-1;
127 ir_nodehashmap_insert(&li->map, bl, irn_live);
130 /* Get the position of the index in the array. */
131 unsigned pos = _be_liveness_bsearch(irn_live, irn);
133 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
134 be_lv_info_node_t *res = &irn_live[pos + 1].node;
136 /* Check, if the irn is in deed in the array. */
137 if (res->node != irn) {
138 be_lv_info_t *payload;
139 unsigned n_members = irn_live[0].head.n_members;
140 unsigned n_size = irn_live[0].head.n_size;
143 if (n_members + 1 >= n_size) {
144 /* double the array size. Remember that the first entry is
145 * metadata about the array and not a real array element */
146 unsigned old_size_bytes = (n_size + 1) * sizeof(irn_live[0]);
147 unsigned new_size = (2 * n_size) + 1;
148 size_t new_size_bytes = new_size * sizeof(irn_live[0]);
149 be_lv_info_t *nw = OALLOCN(&li->obst, be_lv_info_t, new_size);
150 memcpy(nw, irn_live, old_size_bytes);
151 memset(((char*) nw) + old_size_bytes, 0,
152 new_size_bytes - old_size_bytes);
153 nw[0].head.n_size = new_size - 1;
155 ir_nodehashmap_insert(&li->map, bl, nw);
158 payload = &irn_live[1];
159 for (i = n_members; i > pos; --i) {
160 payload[i] = payload[i - 1];
163 ++irn_live[0].head.n_members;
165 res = &payload[pos].node;
174 * Removes a node from the list of live variables of a block.
175 * @return 1 if the node was live at that block, 0 if not.
177 static int be_lv_remove(be_lv_t *li, const ir_node *bl,
180 be_lv_info_t *irn_live = ir_nodehashmap_get(be_lv_info_t, &li->map, bl);
182 if (irn_live != NULL) {
183 unsigned n = irn_live[0].head.n_members;
184 unsigned pos = _be_liveness_bsearch(irn_live, irn);
185 be_lv_info_t *payload = irn_live + 1;
186 be_lv_info_node_t *res = &payload[pos].node;
188 /* The node is in deed in the block's array. Let's remove it. */
189 if (res->node == irn) {
192 for (i = pos + 1; i < n; ++i)
193 payload[i - 1] = payload[i];
195 payload[n - 1].node.node = NULL;
196 payload[n - 1].node.flags = 0;
198 --irn_live[0].head.n_members;
199 DBG((dbg, LEVEL_3, "\tdeleting %+F from %+F at pos %d\n", irn, bl, pos));
208 * Mark a node as live-in in a block.
210 static inline void mark_live_in(be_lv_t *lv, ir_node *block, ir_node *irn)
212 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
213 DBG((dbg, LEVEL_2, "marking %+F live in at %+F\n", irn, block));
214 n->flags |= be_lv_state_in;
218 * Mark a node as live-out in a block.
220 static inline void mark_live_out(be_lv_t *lv, ir_node *block, ir_node *irn)
222 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
223 DBG((dbg, LEVEL_2, "marking %+F live out at %+F\n", irn, block));
224 n->flags |= be_lv_state_out | be_lv_state_end;
228 * Mark a node as live-end in a block.
230 static inline void mark_live_end(be_lv_t *lv, ir_node *block, ir_node *irn)
232 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
233 DBG((dbg, LEVEL_2, "marking %+F live end at %+F\n", irn, block));
234 n->flags |= be_lv_state_end;
238 be_lv_t *lv; /**< The liveness object. */
239 ir_node *def; /**< The node (value). */
240 ir_node *def_block; /**< The block of def. */
241 bitset_t *visited; /**< A set were all visited blocks are recorded. */
245 * Mark a node (value) live out at a certain block. Do this also
246 * transitively, i.e. if the block is not the block of the value's
247 * definition, all predecessors are also marked live.
248 * @param block The block to mark the value live out of.
249 * @param is_true_out Is the node real out there or only live at the end
252 static void live_end_at_block(ir_node *block, int is_true_out)
255 ir_node *def = re.def;
258 mark_live_end(lv, block, def);
260 mark_live_out(lv, block, def);
262 visited = re.visited;
263 if (!bitset_is_set(visited, get_irn_idx(block))) {
264 bitset_set(visited, get_irn_idx(block));
267 * If this block is not the definition block, we have to go up
270 if (re.def_block != block) {
273 mark_live_in(lv, block, def);
275 for (i = get_Block_n_cfgpreds(block) - 1; i >= 0; --i)
276 live_end_at_block(get_Block_cfgpred_block(block, i), 1);
281 typedef struct lv_remove_walker_t {
284 } lv_remove_walker_t;
288 * Liveness analysis for a value.
289 * Compute the set of all blocks a value is live in.
290 * @param irn The node (value).
292 static void liveness_for_node(ir_node *irn)
296 bitset_clear_all(re.visited);
297 def_block = get_nodes_block(irn);
300 re.def_block = def_block;
302 /* Go over all uses of the value */
303 foreach_out_edge(irn, edge) {
304 ir_node *use = edge->src;
307 DBG((dbg, LEVEL_4, "%+F: use at %+F, pos %d in %+F\n", irn, use, edge->pos, get_block(use)));
308 assert(get_irn_n(use, edge->pos) == irn);
311 * If the usage is no data node, skip this use, since it does not
312 * affect the liveness of the node.
314 if (!is_liveness_node(use))
317 /* Get the block where the usage is in. */
318 use_block = get_nodes_block(use);
321 * If the use is a phi function, determine the corresponding block
322 * through which the value reaches the phi function and mark the
323 * value as live out of that block.
326 ir_node *pred_block = get_Block_cfgpred_block(use_block, edge->pos);
327 live_end_at_block(pred_block, 0);
331 * Else, the value is live in at this block. Mark it and call live
332 * out on the predecessors.
334 else if (def_block != use_block) {
337 mark_live_in(re.lv, use_block, irn);
339 for (i = get_Block_n_cfgpreds(use_block) - 1; i >= 0; --i) {
340 ir_node *pred_block = get_Block_cfgpred_block(use_block, i);
341 live_end_at_block(pred_block, 1);
347 static void lv_remove_irn_walker(ir_node *bl, void *data)
349 lv_remove_walker_t *w = (lv_remove_walker_t*)data;
350 be_lv_remove(w->lv, bl, w->irn);
354 * Walker, collect all nodes for which we want calculate liveness info
357 static void collect_liveness_nodes(ir_node *irn, void *data)
359 ir_node **nodes = (ir_node**)data;
360 if (is_liveness_node(irn))
361 nodes[get_irn_idx(irn)] = irn;
364 void be_liveness_compute_sets(be_lv_t *lv)
373 be_timer_push(T_LIVE);
374 ir_nodehashmap_init(&lv->map);
375 obstack_init(&lv->obst);
377 n = get_irg_last_idx(lv->irg);
378 nodes = NEW_ARR_F(ir_node *, n);
379 memset(nodes, 0, sizeof(nodes[0]) * n);
381 /* inserting the variables sorted by their ID is probably
382 * more efficient since the binary sorted set insertion
383 * will not need to move around the data. */
384 irg_walk_graph(lv->irg, NULL, collect_liveness_nodes, nodes);
387 re.visited = bitset_malloc(n);
389 for (i = 0; i < n; ++i) {
390 if (nodes[i] != NULL)
391 liveness_for_node(nodes[i]);
397 be_timer_pop(T_LIVE);
399 lv->sets_valid = true;
402 void be_liveness_compute_chk(be_lv_t *lv)
406 lv->lvc = lv_chk_new(lv->irg);
409 void be_liveness_invalidate_sets(be_lv_t *lv)
413 obstack_free(&lv->obst, NULL);
414 ir_nodehashmap_destroy(&lv->map);
415 lv->sets_valid = false;
418 void be_liveness_invalidate_chk(be_lv_t *lv)
420 be_liveness_invalidate_sets(lv);
424 lv_chk_free(lv->lvc);
428 be_lv_t *be_liveness_new(ir_graph *irg)
430 be_lv_t *lv = XMALLOCZ(be_lv_t);
437 void be_liveness_free(be_lv_t *lv)
439 be_liveness_invalidate_sets(lv);
440 be_liveness_invalidate_chk(lv);
445 void be_liveness_remove(be_lv_t *lv, const ir_node *irn)
447 if (lv->sets_valid) {
448 lv_remove_walker_t w;
451 * Removes a single irn from the liveness information.
452 * Since an irn can only be live at blocks dominated by the block of its
453 * definition, we only have to process that dominance subtree.
457 dom_tree_walk(get_nodes_block(irn), lv_remove_irn_walker, NULL, &w);
461 void be_liveness_introduce(be_lv_t *lv, ir_node *irn)
463 /* Don't compute liveness information for non-data nodes. */
464 if (lv->sets_valid && is_liveness_node(irn)) {
466 re.visited = bitset_malloc(get_irg_last_idx(lv->irg));
467 liveness_for_node(irn);
468 bitset_free(re.visited);
472 void be_liveness_update(be_lv_t *lv, ir_node *irn)
474 be_liveness_remove(lv, irn);
475 be_liveness_introduce(lv, irn);
478 void be_liveness_transfer(const arch_register_class_t *cls,
479 ir_node *node, ir_nodeset_t *nodeset)
481 /* You should better break out of your loop when hitting the first phi
483 assert(!is_Phi(node) && "liveness_transfer produces invalid results for phi nodes");
485 be_foreach_definition(node, cls, value,
486 ir_nodeset_remove(nodeset, value);
489 int arity = get_irn_arity(node);
490 for (int i = 0; i < arity; ++i) {
491 const arch_register_req_t *in_req = arch_get_irn_register_req_in(node, i);
492 if (in_req->cls != cls)
494 ir_node *op = get_irn_n(node, i);
495 const arch_register_req_t *op_req = arch_get_irn_register_req(op);
496 if (arch_register_req_is(op_req, ignore))
498 ir_nodeset_insert(nodeset, op);
504 void be_liveness_end_of_block(const be_lv_t *lv,
505 const arch_register_class_t *cls,
506 const ir_node *block, ir_nodeset_t *live)
508 assert(lv->sets_valid && "live sets must be computed");
509 be_lv_foreach_cls(lv, block, be_lv_state_end, cls, node) {
510 ir_nodeset_insert(live, node);
516 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)
518 ir_node const *const bl = get_nodes_block(pos);
519 be_liveness_end_of_block(lv, cls, bl, live);
520 sched_foreach_reverse(bl, irn) {
521 be_liveness_transfer(cls, irn, live);
527 static void collect_node(ir_node *irn, void *data)
529 struct obstack *obst = (struct obstack*)data;
530 obstack_ptr_grow(obst, irn);
533 static void be_live_chk_compare(be_lv_t *lv, lv_chk_t *lvc)
535 ir_graph *irg = lv->irg;
544 irg_block_walk_graph(irg, collect_node, NULL, &obst);
545 obstack_ptr_grow(&obst, NULL);
546 blocks = (ir_node**)obstack_finish(&obst);
548 irg_walk_graph(irg, collect_node, NULL, &obst);
549 obstack_ptr_grow(&obst, NULL);
550 nodes = (ir_node**)obstack_finish(&obst);
552 stat_ev_ctx_push("be_lv_chk_compare");
553 for (j = 0; nodes[j]; ++j) {
554 ir_node *irn = nodes[j];
558 for (i = 0; blocks[i]; ++i) {
559 ir_node *bl = blocks[i];
560 int lvr_in = be_is_live_in (lv, bl, irn);
561 int lvr_out = be_is_live_out(lv, bl, irn);
562 int lvr_end = be_is_live_end(lv, bl, irn);
564 int lvc_in = lv_chk_bl_in (lvc, bl, irn);
565 int lvc_out = lv_chk_bl_out(lvc, bl, irn);
566 int lvc_end = lv_chk_bl_end(lvc, bl, irn);
568 if (lvr_in - lvc_in != 0)
569 ir_fprintf(stderr, "live in info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_in, lvc_in);
571 if (lvr_end - lvc_end != 0)
572 ir_fprintf(stderr, "live end info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_end, lvc_end);
574 if (lvr_out - lvc_out != 0)
575 ir_fprintf(stderr, "live out info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_out, lvc_out);
578 stat_ev_ctx_pop("be_lv_chk_compare");
580 obstack_free(&obst, NULL);
583 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_live)
584 void be_init_live(void)
586 (void)be_live_chk_compare;
587 FIRM_DBG_REGISTER(dbg, "firm.be.liveness");