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
53 * Filter out some nodes for which we never need liveness.
55 * @param irn the node t check
56 * @return 0 if no liveness info is needed, 1 else
58 static inline int is_liveness_node(const ir_node *irn)
60 switch (get_irn_opcode(irn)) {
72 int (be_is_live_in)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
74 return _be_is_live_xxx(lv, block, irn, be_lv_state_in);
77 int (be_is_live_out)(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_out);
82 int (be_is_live_end)(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_end);
87 static inline unsigned _be_liveness_bsearch(be_lv_info_t *arr, unsigned idx)
89 be_lv_info_t *payload = arr + 1;
91 unsigned n = arr[0].head.n_members;
100 int md = lo + ((hi - lo) >> 1);
101 unsigned md_idx = payload[md].node.idx;
105 else if (idx < md_idx)
109 assert(payload[res].node.idx == idx);
119 be_lv_info_node_t *be_lv_get(const be_lv_t *li, const ir_node *bl,
122 be_lv_info_t *irn_live;
123 be_lv_info_node_t *res = NULL;
126 irn_live = ir_nodehashmap_get(be_lv_info_t, &li->map, bl);
127 if (irn_live != NULL) {
128 unsigned idx = get_irn_idx(irn);
130 /* Get the position of the index in the array. */
131 int pos = _be_liveness_bsearch(irn_live, idx);
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 *rec = &irn_live[pos + 1].node;
136 /* Check, if the irn is in deed in the array. */
140 stat_ev_tim_pop("be_lv_get");
145 static be_lv_info_node_t *be_lv_get_or_set(be_lv_t *li, ir_node *bl,
148 be_lv_info_t *irn_live = ir_nodehashmap_get(be_lv_info_t, &li->map, bl);
149 if (irn_live == NULL) {
150 irn_live = OALLOCNZ(&li->obst, be_lv_info_t, LV_STD_SIZE);
151 irn_live[0].head.n_size = LV_STD_SIZE-1;
152 ir_nodehashmap_insert(&li->map, bl, irn_live);
155 unsigned idx = get_irn_idx(irn);
157 /* Get the position of the index in the array. */
158 unsigned pos = _be_liveness_bsearch(irn_live, idx);
160 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
161 be_lv_info_node_t *res = &irn_live[pos + 1].node;
163 /* Check, if the irn is in deed in the array. */
164 if (res->idx != idx) {
165 be_lv_info_t *payload;
166 unsigned n_members = irn_live[0].head.n_members;
167 unsigned n_size = irn_live[0].head.n_size;
170 if (n_members + 1 >= n_size) {
171 /* double the array size. Remember that the first entry is
172 * metadata about the array and not a real array element */
173 unsigned old_size_bytes = (n_size + 1) * sizeof(irn_live[0]);
174 unsigned new_size = (2 * n_size) + 1;
175 size_t new_size_bytes = new_size * sizeof(irn_live[0]);
176 be_lv_info_t *nw = OALLOCN(&li->obst, be_lv_info_t, new_size);
177 memcpy(nw, irn_live, old_size_bytes);
178 memset(((char*) nw) + old_size_bytes, 0,
179 new_size_bytes - old_size_bytes);
180 nw[0].head.n_size = new_size - 1;
182 ir_nodehashmap_insert(&li->map, bl, nw);
185 payload = &irn_live[1];
186 for (i = n_members; i > pos; --i) {
187 payload[i] = payload[i - 1];
190 ++irn_live[0].head.n_members;
192 res = &payload[pos].node;
201 * Removes a node from the list of live variables of a block.
202 * @return 1 if the node was live at that block, 0 if not.
204 static int be_lv_remove(be_lv_t *li, const ir_node *bl,
207 be_lv_info_t *irn_live = ir_nodehashmap_get(be_lv_info_t, &li->map, bl);
209 if (irn_live != NULL) {
210 unsigned n = irn_live[0].head.n_members;
211 unsigned idx = get_irn_idx(irn);
212 unsigned pos = _be_liveness_bsearch(irn_live, idx);
213 be_lv_info_t *payload = irn_live + 1;
214 be_lv_info_node_t *res = &payload[pos].node;
216 /* The node is in deed in the block's array. Let's remove it. */
217 if (res->idx == idx) {
220 for (i = pos + 1; i < n; ++i)
221 payload[i - 1] = payload[i];
223 payload[n - 1].node.idx = 0;
224 payload[n - 1].node.flags = 0;
226 --irn_live[0].head.n_members;
227 DBG((dbg, LEVEL_3, "\tdeleting %+F from %+F at pos %d\n", irn, bl, pos));
236 * Mark a node as live-in in a block.
238 static inline void mark_live_in(be_lv_t *lv, ir_node *block, ir_node *irn)
240 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
241 DBG((dbg, LEVEL_2, "marking %+F live in at %+F\n", irn, block));
242 n->flags |= be_lv_state_in;
246 * Mark a node as live-out in a block.
248 static inline void mark_live_out(be_lv_t *lv, ir_node *block, ir_node *irn)
250 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
251 DBG((dbg, LEVEL_2, "marking %+F live out at %+F\n", irn, block));
252 n->flags |= be_lv_state_out | be_lv_state_end;
256 * Mark a node as live-end in a block.
258 static inline void mark_live_end(be_lv_t *lv, ir_node *block, ir_node *irn)
260 be_lv_info_node_t *n = be_lv_get_or_set(lv, block, irn);
261 DBG((dbg, LEVEL_2, "marking %+F live end at %+F\n", irn, block));
262 n->flags |= be_lv_state_end;
266 be_lv_t *lv; /**< The liveness object. */
267 ir_node *def; /**< The node (value). */
268 ir_node *def_block; /**< The block of def. */
269 bitset_t *visited; /**< A set were all visited blocks are recorded. */
273 * Mark a node (value) live out at a certain block. Do this also
274 * transitively, i.e. if the block is not the block of the value's
275 * definition, all predecessors are also marked live.
276 * @param block The block to mark the value live out of.
277 * @param is_true_out Is the node real out there or only live at the end
280 static void live_end_at_block(ir_node *block, int is_true_out)
283 ir_node *def = re.def;
286 mark_live_end(lv, block, def);
288 mark_live_out(lv, block, def);
290 visited = re.visited;
291 if (!bitset_is_set(visited, get_irn_idx(block))) {
292 bitset_set(visited, get_irn_idx(block));
295 * If this block is not the definition block, we have to go up
298 if (re.def_block != block) {
301 mark_live_in(lv, block, def);
303 for (i = get_Block_n_cfgpreds(block) - 1; i >= 0; --i)
304 live_end_at_block(get_Block_cfgpred_block(block, i), 1);
309 typedef struct lv_remove_walker_t {
312 } lv_remove_walker_t;
316 * Liveness analysis for a value.
317 * Compute the set of all blocks a value is live in.
318 * @param irn The node (value).
320 static void liveness_for_node(ir_node *irn)
324 bitset_clear_all(re.visited);
325 def_block = get_nodes_block(irn);
328 re.def_block = def_block;
330 /* Go over all uses of the value */
331 foreach_out_edge(irn, edge) {
332 ir_node *use = edge->src;
335 DBG((dbg, LEVEL_4, "%+F: use at %+F, pos %d in %+F\n", irn, use, edge->pos, get_block(use)));
336 assert(get_irn_n(use, edge->pos) == irn);
339 * If the usage is no data node, skip this use, since it does not
340 * affect the liveness of the node.
342 if (!is_liveness_node(use))
345 /* Get the block where the usage is in. */
346 use_block = get_nodes_block(use);
349 * If the use is a phi function, determine the corresponding block
350 * through which the value reaches the phi function and mark the
351 * value as live out of that block.
354 ir_node *pred_block = get_Block_cfgpred_block(use_block, edge->pos);
355 live_end_at_block(pred_block, 0);
359 * Else, the value is live in at this block. Mark it and call live
360 * out on the predecessors.
362 else if (def_block != use_block) {
365 mark_live_in(re.lv, use_block, irn);
367 for (i = get_Block_n_cfgpreds(use_block) - 1; i >= 0; --i) {
368 ir_node *pred_block = get_Block_cfgpred_block(use_block, i);
369 live_end_at_block(pred_block, 1);
375 static void lv_remove_irn_walker(ir_node *bl, void *data)
377 lv_remove_walker_t *w = (lv_remove_walker_t*)data;
378 be_lv_remove(w->lv, bl, w->irn);
382 * Walker, collect all nodes for which we want calculate liveness info
385 static void collect_liveness_nodes(ir_node *irn, void *data)
387 ir_node **nodes = (ir_node**)data;
388 if (is_liveness_node(irn))
389 nodes[get_irn_idx(irn)] = irn;
392 void be_liveness_compute_sets(be_lv_t *lv)
401 be_timer_push(T_LIVE);
402 ir_nodehashmap_init(&lv->map);
403 obstack_init(&lv->obst);
405 n = get_irg_last_idx(lv->irg);
406 nodes = NEW_ARR_F(ir_node *, n);
407 memset(nodes, 0, sizeof(nodes[0]) * n);
409 /* inserting the variables sorted by their ID is probably
410 * more efficient since the binary sorted set insertion
411 * will not need to move around the data. */
412 irg_walk_graph(lv->irg, NULL, collect_liveness_nodes, nodes);
415 re.visited = bitset_malloc(n);
417 for (i = 0; i < n; ++i) {
418 if (nodes[i] != NULL)
419 liveness_for_node(nodes[i]);
424 register_hook(hook_node_info, &lv->hook_info);
426 be_timer_pop(T_LIVE);
428 lv->sets_valid = true;
431 void be_liveness_compute_chk(be_lv_t *lv)
435 lv->lvc = lv_chk_new(lv->irg);
438 void be_liveness_invalidate_sets(be_lv_t *lv)
442 unregister_hook(hook_node_info, &lv->hook_info);
443 obstack_free(&lv->obst, NULL);
444 ir_nodehashmap_destroy(&lv->map);
445 lv->sets_valid = false;
448 void be_liveness_invalidate_chk(be_lv_t *lv)
450 be_liveness_invalidate_sets(lv);
454 lv_chk_free(lv->lvc);
458 be_lv_t *be_liveness_new(ir_graph *irg)
460 be_lv_t *lv = XMALLOCZ(be_lv_t);
463 lv->hook_info.context = lv;
464 lv->hook_info.hook._hook_node_info = be_dump_liveness_block;
469 void be_liveness_free(be_lv_t *lv)
471 be_liveness_invalidate_sets(lv);
472 be_liveness_invalidate_chk(lv);
477 void be_liveness_remove(be_lv_t *lv, const ir_node *irn)
479 if (lv->sets_valid) {
480 lv_remove_walker_t w;
483 * Removes a single irn from the liveness information.
484 * Since an irn can only be live at blocks dominated by the block of its
485 * definition, we only have to process that dominance subtree.
489 dom_tree_walk(get_nodes_block(irn), lv_remove_irn_walker, NULL, &w);
493 void be_liveness_introduce(be_lv_t *lv, ir_node *irn)
495 /* Don't compute liveness information for non-data nodes. */
496 if (lv->sets_valid && is_liveness_node(irn)) {
498 re.visited = bitset_malloc(get_irg_last_idx(lv->irg));
499 liveness_for_node(irn);
500 bitset_free(re.visited);
504 void be_liveness_update(be_lv_t *lv, ir_node *irn)
506 be_liveness_remove(lv, irn);
507 be_liveness_introduce(lv, irn);
510 void be_liveness_transfer(const arch_register_class_t *cls,
511 ir_node *node, ir_nodeset_t *nodeset)
513 /* You should better break out of your loop when hitting the first phi
515 assert(!is_Phi(node) && "liveness_transfer produces invalid results for phi nodes");
517 be_foreach_definition(node, cls, value,
518 ir_nodeset_remove(nodeset, value);
521 int arity = get_irn_arity(node);
522 for (int i = 0; i < arity; ++i) {
523 ir_node *op = get_irn_n(node, i);
524 if (!arch_irn_consider_in_reg_alloc(cls, op))
526 ir_nodeset_insert(nodeset, op);
532 void be_liveness_end_of_block(const be_lv_t *lv,
533 const arch_register_class_t *cls,
534 const ir_node *block, ir_nodeset_t *live)
536 assert(lv->sets_valid && "live sets must be computed");
537 be_lv_foreach(lv, block, be_lv_state_end, node) {
538 if (!arch_irn_consider_in_reg_alloc(cls, node))
541 ir_nodeset_insert(live, node);
547 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)
549 ir_node const *const bl = get_nodes_block(pos);
550 be_liveness_end_of_block(lv, cls, bl, live);
551 sched_foreach_reverse(bl, irn) {
552 be_liveness_transfer(cls, irn, live);
558 static void collect_node(ir_node *irn, void *data)
560 struct obstack *obst = (struct obstack*)data;
561 obstack_ptr_grow(obst, irn);
564 static void be_live_chk_compare(be_lv_t *lv, lv_chk_t *lvc)
566 ir_graph *irg = lv->irg;
575 irg_block_walk_graph(irg, collect_node, NULL, &obst);
576 obstack_ptr_grow(&obst, NULL);
577 blocks = (ir_node**)obstack_finish(&obst);
579 irg_walk_graph(irg, collect_node, NULL, &obst);
580 obstack_ptr_grow(&obst, NULL);
581 nodes = (ir_node**)obstack_finish(&obst);
583 stat_ev_ctx_push("be_lv_chk_compare");
584 for (j = 0; nodes[j]; ++j) {
585 ir_node *irn = nodes[j];
589 for (i = 0; blocks[i]; ++i) {
590 ir_node *bl = blocks[i];
591 int lvr_in = be_is_live_in (lv, bl, irn);
592 int lvr_out = be_is_live_out(lv, bl, irn);
593 int lvr_end = be_is_live_end(lv, bl, irn);
595 int lvc_in = lv_chk_bl_in (lvc, bl, irn);
596 int lvc_out = lv_chk_bl_out(lvc, bl, irn);
597 int lvc_end = lv_chk_bl_end(lvc, bl, irn);
599 if (lvr_in - lvc_in != 0)
600 ir_fprintf(stderr, "live in info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_in, lvc_in);
602 if (lvr_end - lvc_end != 0)
603 ir_fprintf(stderr, "live end info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_end, lvc_end);
605 if (lvr_out - lvc_out != 0)
606 ir_fprintf(stderr, "live out info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_out, lvc_out);
609 stat_ev_ctx_pop("be_lv_chk_compare");
611 obstack_free(&obst, NULL);
614 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_live)
615 void be_init_live(void)
617 (void)be_live_chk_compare;
618 FIRM_DBG_REGISTER(dbg, "firm.be.liveness");