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
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, unsigned idx)
88 be_lv_info_t *payload = arr + 1;
90 unsigned n = arr[0].head.n_members;
99 int md = lo + ((hi - lo) >> 1);
100 unsigned md_idx = payload[md].node.idx;
104 else if (idx < md_idx)
108 assert(payload[res].node.idx == idx);
118 be_lv_info_node_t *be_lv_get(const be_lv_t *li, const ir_node *bl,
121 be_lv_info_t *irn_live;
122 be_lv_info_node_t *res = NULL;
125 irn_live = ir_nodehashmap_get(be_lv_info_t, &li->map, bl);
126 if (irn_live != NULL) {
127 unsigned idx = get_irn_idx(irn);
129 /* Get the position of the index in the array. */
130 int pos = _be_liveness_bsearch(irn_live, idx);
132 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
133 be_lv_info_node_t *rec = &irn_live[pos + 1].node;
135 /* Check, if the irn is in deed in the array. */
139 stat_ev_tim_pop("be_lv_get");
144 static be_lv_info_node_t *be_lv_get_or_set(be_lv_t *li, ir_node *bl,
147 be_lv_info_t *irn_live = ir_nodehashmap_get(be_lv_info_t, &li->map, bl);
148 if (irn_live == NULL) {
149 irn_live = OALLOCNZ(&li->obst, be_lv_info_t, LV_STD_SIZE);
150 irn_live[0].head.n_size = LV_STD_SIZE-1;
151 ir_nodehashmap_insert(&li->map, bl, irn_live);
154 unsigned idx = get_irn_idx(irn);
156 /* Get the position of the index in the array. */
157 unsigned pos = _be_liveness_bsearch(irn_live, idx);
159 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
160 be_lv_info_node_t *res = &irn_live[pos + 1].node;
162 /* Check, if the irn is in deed in the array. */
163 if (res->idx != idx) {
164 be_lv_info_t *payload;
165 unsigned n_members = irn_live[0].head.n_members;
166 unsigned n_size = irn_live[0].head.n_size;
169 if (n_members + 1 >= n_size) {
170 /* double the array size. Remember that the first entry is
171 * metadata about the array and not a real array element */
172 unsigned old_size_bytes = (n_size + 1) * sizeof(irn_live[0]);
173 unsigned new_size = (2 * n_size) + 1;
174 size_t new_size_bytes = new_size * sizeof(irn_live[0]);
175 be_lv_info_t *nw = OALLOCN(&li->obst, be_lv_info_t, new_size);
176 memcpy(nw, irn_live, old_size_bytes);
177 memset(((char*) nw) + old_size_bytes, 0,
178 new_size_bytes - old_size_bytes);
179 nw[0].head.n_size = new_size - 1;
181 ir_nodehashmap_insert(&li->map, bl, nw);
184 payload = &irn_live[1];
185 for (i = n_members; i > pos; --i) {
186 payload[i] = payload[i - 1];
189 ++irn_live[0].head.n_members;
191 res = &payload[pos].node;
200 * Removes a node from the list of live variables of a block.
201 * @return 1 if the node was live at that block, 0 if not.
203 static int be_lv_remove(be_lv_t *li, const ir_node *bl,
206 be_lv_info_t *irn_live = ir_nodehashmap_get(be_lv_info_t, &li->map, bl);
208 if (irn_live != NULL) {
209 unsigned n = irn_live[0].head.n_members;
210 unsigned idx = get_irn_idx(irn);
211 unsigned pos = _be_liveness_bsearch(irn_live, idx);
212 be_lv_info_t *payload = irn_live + 1;
213 be_lv_info_node_t *res = &payload[pos].node;
215 /* The node is in deed in the block's array. Let's remove it. */
216 if (res->idx == idx) {
219 for (i = pos + 1; i < n; ++i)
220 payload[i - 1] = payload[i];
222 payload[n - 1].node.idx = 0;
223 payload[n - 1].node.flags = 0;
225 --irn_live[0].head.n_members;
226 DBG((dbg, LEVEL_3, "\tdeleting %+F from %+F at pos %d\n", irn, bl, pos));
235 * Mark a node as live-in in a block.
237 static inline void mark_live_in(be_lv_t *lv, ir_node *block, ir_node *irn)
239 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
240 DBG((dbg, LEVEL_2, "marking %+F live in at %+F\n", irn, block));
241 n->flags |= be_lv_state_in;
245 * Mark a node as live-out in a block.
247 static inline void mark_live_out(be_lv_t *lv, ir_node *block, ir_node *irn)
249 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
250 DBG((dbg, LEVEL_2, "marking %+F live out at %+F\n", irn, block));
251 n->flags |= be_lv_state_out | be_lv_state_end;
255 * Mark a node as live-end in a block.
257 static inline void mark_live_end(be_lv_t *lv, ir_node *block, ir_node *irn)
259 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
260 DBG((dbg, LEVEL_2, "marking %+F live end at %+F\n", irn, block));
261 n->flags |= be_lv_state_end;
265 be_lv_t *lv; /**< The liveness object. */
266 ir_node *def; /**< The node (value). */
267 ir_node *def_block; /**< The block of def. */
268 bitset_t *visited; /**< A set were all visited blocks are recorded. */
272 * Mark a node (value) live out at a certain block. Do this also
273 * transitively, i.e. if the block is not the block of the value's
274 * definition, all predecessors are also marked live.
275 * @param block The block to mark the value live out of.
276 * @param is_true_out Is the node real out there or only live at the end
279 static void live_end_at_block(ir_node *block, int is_true_out)
282 ir_node *def = re.def;
285 mark_live_end(lv, block, def);
287 mark_live_out(lv, block, def);
289 visited = re.visited;
290 if (!bitset_is_set(visited, get_irn_idx(block))) {
291 bitset_set(visited, get_irn_idx(block));
294 * If this block is not the definition block, we have to go up
297 if (re.def_block != block) {
300 mark_live_in(lv, block, def);
302 for (i = get_Block_n_cfgpreds(block) - 1; i >= 0; --i)
303 live_end_at_block(get_Block_cfgpred_block(block, i), 1);
308 typedef struct lv_remove_walker_t {
311 } lv_remove_walker_t;
315 * Liveness analysis for a value.
316 * Compute the set of all blocks a value is live in.
317 * @param irn The node (value).
319 static void liveness_for_node(ir_node *irn)
323 bitset_clear_all(re.visited);
324 def_block = get_nodes_block(irn);
327 re.def_block = def_block;
329 /* Go over all uses of the value */
330 foreach_out_edge(irn, edge) {
331 ir_node *use = edge->src;
334 DBG((dbg, LEVEL_4, "%+F: use at %+F, pos %d in %+F\n", irn, use, edge->pos, get_block(use)));
335 assert(get_irn_n(use, edge->pos) == irn);
338 * If the usage is no data node, skip this use, since it does not
339 * affect the liveness of the node.
341 if (!is_liveness_node(use))
344 /* Get the block where the usage is in. */
345 use_block = get_nodes_block(use);
348 * If the use is a phi function, determine the corresponding block
349 * through which the value reaches the phi function and mark the
350 * value as live out of that block.
353 ir_node *pred_block = get_Block_cfgpred_block(use_block, edge->pos);
354 live_end_at_block(pred_block, 0);
358 * Else, the value is live in at this block. Mark it and call live
359 * out on the predecessors.
361 else if (def_block != use_block) {
364 mark_live_in(re.lv, use_block, irn);
366 for (i = get_Block_n_cfgpreds(use_block) - 1; i >= 0; --i) {
367 ir_node *pred_block = get_Block_cfgpred_block(use_block, i);
368 live_end_at_block(pred_block, 1);
374 static void lv_remove_irn_walker(ir_node *bl, void *data)
376 lv_remove_walker_t *w = (lv_remove_walker_t*)data;
377 be_lv_remove(w->lv, bl, w->irn);
381 * Walker, collect all nodes for which we want calculate liveness info
384 static void collect_liveness_nodes(ir_node *irn, void *data)
386 ir_node **nodes = (ir_node**)data;
387 if (is_liveness_node(irn))
388 nodes[get_irn_idx(irn)] = irn;
391 void be_liveness_compute_sets(be_lv_t *lv)
400 be_timer_push(T_LIVE);
401 ir_nodehashmap_init(&lv->map);
402 obstack_init(&lv->obst);
404 n = get_irg_last_idx(lv->irg);
405 nodes = NEW_ARR_F(ir_node *, n);
406 memset(nodes, 0, sizeof(nodes[0]) * n);
408 /* inserting the variables sorted by their ID is probably
409 * more efficient since the binary sorted set insertion
410 * will not need to move around the data. */
411 irg_walk_graph(lv->irg, NULL, collect_liveness_nodes, nodes);
414 re.visited = bitset_malloc(n);
416 for (i = 0; i < n; ++i) {
417 if (nodes[i] != NULL)
418 liveness_for_node(nodes[i]);
423 register_hook(hook_node_info, &lv->hook_info);
425 be_timer_pop(T_LIVE);
427 lv->sets_valid = true;
430 void be_liveness_compute_chk(be_lv_t *lv)
434 lv->lvc = lv_chk_new(lv->irg);
437 void be_liveness_invalidate_sets(be_lv_t *lv)
441 unregister_hook(hook_node_info, &lv->hook_info);
442 obstack_free(&lv->obst, NULL);
443 ir_nodehashmap_destroy(&lv->map);
444 lv->sets_valid = false;
447 void be_liveness_invalidate_chk(be_lv_t *lv)
449 be_liveness_invalidate_sets(lv);
453 lv_chk_free(lv->lvc);
457 be_lv_t *be_liveness_new(ir_graph *irg)
459 be_lv_t *lv = XMALLOCZ(be_lv_t);
462 lv->hook_info.context = lv;
463 lv->hook_info.hook._hook_node_info = be_dump_liveness_block;
468 void be_liveness_free(be_lv_t *lv)
470 be_liveness_invalidate_sets(lv);
471 be_liveness_invalidate_chk(lv);
476 void be_liveness_remove(be_lv_t *lv, const ir_node *irn)
478 if (lv->sets_valid) {
479 lv_remove_walker_t w;
482 * Removes a single irn from the liveness information.
483 * Since an irn can only be live at blocks dominated by the block of its
484 * definition, we only have to process that dominance subtree.
488 dom_tree_walk(get_nodes_block(irn), lv_remove_irn_walker, NULL, &w);
492 void be_liveness_introduce(be_lv_t *lv, ir_node *irn)
494 /* Don't compute liveness information for non-data nodes. */
495 if (lv->sets_valid && is_liveness_node(irn)) {
497 re.visited = bitset_malloc(get_irg_last_idx(lv->irg));
498 liveness_for_node(irn);
499 bitset_free(re.visited);
503 void be_liveness_update(be_lv_t *lv, ir_node *irn)
505 be_liveness_remove(lv, irn);
506 be_liveness_introduce(lv, irn);
509 void be_liveness_transfer(const arch_register_class_t *cls,
510 ir_node *node, ir_nodeset_t *nodeset)
514 /* You should better break out of your loop when hitting the first phi
516 assert(!is_Phi(node) && "liveness_transfer produces invalid results for phi nodes");
518 if (get_irn_mode(node) == mode_T) {
519 foreach_out_edge(node, edge) {
520 ir_node *proj = get_edge_src_irn(edge);
522 if (arch_irn_consider_in_reg_alloc(cls, proj)) {
523 ir_nodeset_remove(nodeset, proj);
526 } else if (arch_irn_consider_in_reg_alloc(cls, node)) {
527 ir_nodeset_remove(nodeset, node);
530 arity = get_irn_arity(node);
531 for (i = 0; i < arity; ++i) {
532 ir_node *op = get_irn_n(node, i);
534 if (arch_irn_consider_in_reg_alloc(cls, op))
535 ir_nodeset_insert(nodeset, op);
541 void be_liveness_end_of_block(const be_lv_t *lv,
542 const arch_register_class_t *cls,
543 const ir_node *block, ir_nodeset_t *live)
545 assert(lv->sets_valid && "live sets must be computed");
546 be_lv_foreach(lv, block, be_lv_state_end, node) {
547 if (!arch_irn_consider_in_reg_alloc(cls, node))
550 ir_nodeset_insert(live, node);
556 void be_liveness_nodes_live_at(const be_lv_t *lv,
557 const arch_register_class_t *cls,
558 const ir_node *pos, ir_nodeset_t *live)
560 const ir_node *bl = is_Block(pos) ? pos : get_nodes_block(pos);
562 be_liveness_end_of_block(lv, cls, bl, live);
563 sched_foreach_reverse(bl, irn) {
565 * If we encounter the node we want to insert the Perm after,
566 * exit immediately, so that this node is still live
571 be_liveness_transfer(cls, irn, live);
575 static void collect_node(ir_node *irn, void *data)
577 struct obstack *obst = (struct obstack*)data;
578 obstack_ptr_grow(obst, irn);
581 static void be_live_chk_compare(be_lv_t *lv, lv_chk_t *lvc)
583 ir_graph *irg = lv->irg;
592 irg_block_walk_graph(irg, collect_node, NULL, &obst);
593 obstack_ptr_grow(&obst, NULL);
594 blocks = (ir_node**)obstack_finish(&obst);
596 irg_walk_graph(irg, collect_node, NULL, &obst);
597 obstack_ptr_grow(&obst, NULL);
598 nodes = (ir_node**)obstack_finish(&obst);
600 stat_ev_ctx_push("be_lv_chk_compare");
601 for (j = 0; nodes[j]; ++j) {
602 ir_node *irn = nodes[j];
606 for (i = 0; blocks[i]; ++i) {
607 ir_node *bl = blocks[i];
608 int lvr_in = be_is_live_in (lv, bl, irn);
609 int lvr_out = be_is_live_out(lv, bl, irn);
610 int lvr_end = be_is_live_end(lv, bl, irn);
612 int lvc_in = lv_chk_bl_in (lvc, bl, irn);
613 int lvc_out = lv_chk_bl_out(lvc, bl, irn);
614 int lvc_end = lv_chk_bl_end(lvc, bl, irn);
616 if (lvr_in - lvc_in != 0)
617 ir_fprintf(stderr, "live in info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_in, lvc_in);
619 if (lvr_end - lvc_end != 0)
620 ir_fprintf(stderr, "live end info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_end, lvc_end);
622 if (lvr_out - lvc_out != 0)
623 ir_fprintf(stderr, "live out info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_out, lvc_out);
626 stat_ev_ctx_pop("be_lv_chk_compare");
628 obstack_free(&obst, NULL);
631 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_live)
632 void be_init_live(void)
634 (void)be_live_chk_compare;
635 FIRM_DBG_REGISTER(dbg, "firm.be.liveness");