2 * This file is part of libFirm.
3 * Copyright (C) 2012 University of Karlsruhe.
8 * @brief Interblock liveness analysis.
9 * @author Sebastian Hack
14 /* statev is expensive here, only enable when needed */
15 #define DISABLE_STATEV
17 #include "iredges_t.h"
21 #include "irnodeset.h"
32 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
34 #define LV_STD_SIZE 64
36 int (be_is_live_in)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
38 return _be_is_live_xxx(lv, block, irn, be_lv_state_in);
41 int (be_is_live_out)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
43 return _be_is_live_xxx(lv, block, irn, be_lv_state_out);
46 int (be_is_live_end)(const be_lv_t *lv, const ir_node *block, const ir_node *irn)
48 return _be_is_live_xxx(lv, block, irn, be_lv_state_end);
51 static inline unsigned _be_liveness_bsearch(be_lv_info_t *arr, const ir_node *node)
53 be_lv_info_t *payload = arr + 1;
55 unsigned n = arr[0].head.n_members;
64 int md = lo + ((hi - lo) >> 1);
65 ir_node *md_node = payload[md].node.node;
69 else if (node < md_node)
82 be_lv_info_node_t *be_lv_get(const be_lv_t *li, const ir_node *bl,
85 be_lv_info_t *irn_live;
86 be_lv_info_node_t *res = NULL;
89 irn_live = ir_nodehashmap_get(be_lv_info_t, &li->map, bl);
90 if (irn_live != NULL) {
91 /* Get the position of the index in the array. */
92 int pos = _be_liveness_bsearch(irn_live, irn);
94 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
95 be_lv_info_node_t *rec = &irn_live[pos + 1].node;
97 /* Check, if the irn is in deed in the array. */
101 stat_ev_tim_pop("be_lv_get");
106 static be_lv_info_node_t *be_lv_get_or_set(be_lv_t *li, ir_node *bl,
109 be_lv_info_t *irn_live = ir_nodehashmap_get(be_lv_info_t, &li->map, bl);
110 if (irn_live == NULL) {
111 irn_live = OALLOCNZ(&li->obst, be_lv_info_t, LV_STD_SIZE);
112 irn_live[0].head.n_size = LV_STD_SIZE-1;
113 ir_nodehashmap_insert(&li->map, bl, irn_live);
116 /* Get the position of the index in the array. */
117 unsigned pos = _be_liveness_bsearch(irn_live, irn);
119 /* Get the record in question. 1 must be added, since the first record contains information about the array and must be skipped. */
120 be_lv_info_node_t *res = &irn_live[pos + 1].node;
122 /* Check, if the irn is in deed in the array. */
123 if (res->node != irn) {
124 be_lv_info_t *payload;
125 unsigned n_members = irn_live[0].head.n_members;
126 unsigned n_size = irn_live[0].head.n_size;
129 if (n_members + 1 >= n_size) {
130 /* double the array size. Remember that the first entry is
131 * metadata about the array and not a real array element */
132 unsigned old_size_bytes = (n_size + 1) * sizeof(irn_live[0]);
133 unsigned new_size = (2 * n_size) + 1;
134 size_t new_size_bytes = new_size * sizeof(irn_live[0]);
135 be_lv_info_t *nw = OALLOCN(&li->obst, be_lv_info_t, new_size);
136 memcpy(nw, irn_live, old_size_bytes);
137 memset(((char*) nw) + old_size_bytes, 0,
138 new_size_bytes - old_size_bytes);
139 nw[0].head.n_size = new_size - 1;
141 ir_nodehashmap_insert(&li->map, bl, nw);
144 payload = &irn_live[1];
145 for (i = n_members; i > pos; --i) {
146 payload[i] = payload[i - 1];
149 ++irn_live[0].head.n_members;
151 res = &payload[pos].node;
160 * Removes a node from the list of live variables of a block.
161 * @return 1 if the node was live at that block, 0 if not.
163 static int be_lv_remove(be_lv_t *li, const ir_node *bl,
166 be_lv_info_t *irn_live = ir_nodehashmap_get(be_lv_info_t, &li->map, bl);
168 if (irn_live != NULL) {
169 unsigned n = irn_live[0].head.n_members;
170 unsigned pos = _be_liveness_bsearch(irn_live, irn);
171 be_lv_info_t *payload = irn_live + 1;
172 be_lv_info_node_t *res = &payload[pos].node;
174 /* The node is in deed in the block's array. Let's remove it. */
175 if (res->node == irn) {
178 for (i = pos + 1; i < n; ++i)
179 payload[i - 1] = payload[i];
181 payload[n - 1].node.node = NULL;
182 payload[n - 1].node.flags = 0;
184 --irn_live[0].head.n_members;
185 DBG((dbg, LEVEL_3, "\tdeleting %+F from %+F at pos %d\n", irn, bl, pos));
194 be_lv_t *lv; /**< The liveness object. */
195 ir_node *def; /**< The node (value). */
196 ir_node *def_block; /**< The block of def. */
200 * Mark a node (value) live out at a certain block. Do this also
201 * transitively, i.e. if the block is not the block of the value's
202 * definition, all predecessors are also marked live.
203 * @param block The block to mark the value live out of.
204 * @param state The liveness bits to set, either end or end+out.
206 static void live_end_at_block(ir_node *const block, be_lv_state_t const state)
208 be_lv_info_node_t *const n = be_lv_get_or_set(re.lv, block, re.def);
209 be_lv_state_t const before = n->flags;
211 assert(state == be_lv_state_end || state == (be_lv_state_end | be_lv_state_out));
212 DBG((dbg, LEVEL_2, "marking %+F live %s at %+F\n", re.def, state & be_lv_state_out ? "end+out" : "end", block));
215 /* There is no need to recurse further, if we where here before (i.e., any
216 * live state bits were set before). */
217 if (before != be_lv_state_none)
220 /* Stop going up further, if this is the block of the definition. */
221 if (re.def_block == block)
224 DBG((dbg, LEVEL_2, "marking %+F live in at %+F\n", re.def, block));
225 n->flags |= be_lv_state_in;
227 for (int i = get_Block_n_cfgpreds(block); i-- != 0;) {
228 ir_node *const pred_block = get_Block_cfgpred_block(block, i);
229 live_end_at_block(pred_block, be_lv_state_end | be_lv_state_out);
233 typedef struct lv_remove_walker_t {
236 } lv_remove_walker_t;
240 * Liveness analysis for a value.
241 * Compute the set of all blocks a value is live in.
242 * @param irn The node (value).
244 static void liveness_for_node(ir_node *irn)
246 ir_node *const def_block = get_nodes_block(irn);
249 re.def_block = def_block;
251 /* Go over all uses of the value */
252 foreach_out_edge(irn, edge) {
253 ir_node *use = edge->src;
256 DBG((dbg, LEVEL_4, "%+F: use at %+F, pos %d in %+F\n", irn, use, edge->pos, get_block(use)));
257 assert(get_irn_n(use, edge->pos) == irn);
260 * If the usage is no data node, skip this use, since it does not
261 * affect the liveness of the node.
263 if (!is_liveness_node(use))
266 /* Get the block where the usage is in. */
267 use_block = get_nodes_block(use);
270 * If the use is a phi function, determine the corresponding block
271 * through which the value reaches the phi function and mark the
272 * value as live out of that block.
275 ir_node *pred_block = get_Block_cfgpred_block(use_block, edge->pos);
276 live_end_at_block(pred_block, be_lv_state_end);
280 * Else, the value is live in at this block. Mark it and call live
281 * out on the predecessors.
283 else if (def_block != use_block) {
286 be_lv_info_node_t *const n = be_lv_get_or_set(re.lv, use_block, irn);
287 DBG((dbg, LEVEL_2, "marking %+F live in at %+F\n", irn, use_block));
288 n->flags |= be_lv_state_in;
290 for (i = get_Block_n_cfgpreds(use_block) - 1; i >= 0; --i) {
291 ir_node *pred_block = get_Block_cfgpred_block(use_block, i);
292 live_end_at_block(pred_block, be_lv_state_end | be_lv_state_out);
298 static void lv_remove_irn_walker(ir_node *bl, void *data)
300 lv_remove_walker_t *w = (lv_remove_walker_t*)data;
301 be_lv_remove(w->lv, bl, w->irn);
305 * Walker, collect all nodes for which we want calculate liveness info
308 static void collect_liveness_nodes(ir_node *irn, void *data)
310 ir_node **nodes = (ir_node**)data;
311 if (is_liveness_node(irn))
312 nodes[get_irn_idx(irn)] = irn;
315 void be_liveness_compute_sets(be_lv_t *lv)
323 be_timer_push(T_LIVE);
324 ir_nodehashmap_init(&lv->map);
325 obstack_init(&lv->obst);
327 n = get_irg_last_idx(lv->irg);
328 ir_node **const nodes = NEW_ARR_FZ(ir_node*, n);
330 /* inserting the variables sorted by their ID is probably
331 * more efficient since the binary sorted set insertion
332 * will not need to move around the data. */
333 irg_walk_graph(lv->irg, NULL, collect_liveness_nodes, nodes);
337 for (i = 0; i < n; ++i) {
338 if (nodes[i] != NULL)
339 liveness_for_node(nodes[i]);
344 be_timer_pop(T_LIVE);
346 lv->sets_valid = true;
349 void be_liveness_compute_chk(be_lv_t *lv)
353 lv->lvc = lv_chk_new(lv->irg);
356 void be_liveness_invalidate_sets(be_lv_t *lv)
360 obstack_free(&lv->obst, NULL);
361 ir_nodehashmap_destroy(&lv->map);
362 lv->sets_valid = false;
365 void be_liveness_invalidate_chk(be_lv_t *lv)
367 be_liveness_invalidate_sets(lv);
371 lv_chk_free(lv->lvc);
375 be_lv_t *be_liveness_new(ir_graph *irg)
377 be_lv_t *lv = XMALLOCZ(be_lv_t);
384 void be_liveness_free(be_lv_t *lv)
386 be_liveness_invalidate_sets(lv);
387 be_liveness_invalidate_chk(lv);
392 void be_liveness_remove(be_lv_t *lv, const ir_node *irn)
394 if (lv->sets_valid) {
395 lv_remove_walker_t w;
398 * Removes a single irn from the liveness information.
399 * Since an irn can only be live at blocks dominated by the block of its
400 * definition, we only have to process that dominance subtree.
404 dom_tree_walk(get_nodes_block(irn), lv_remove_irn_walker, NULL, &w);
408 void be_liveness_introduce(be_lv_t *lv, ir_node *irn)
410 /* Don't compute liveness information for non-data nodes. */
411 if (lv->sets_valid && is_liveness_node(irn)) {
413 liveness_for_node(irn);
417 void be_liveness_update(be_lv_t *lv, ir_node *irn)
419 be_liveness_remove(lv, irn);
420 be_liveness_introduce(lv, irn);
423 void be_liveness_transfer(const arch_register_class_t *cls,
424 ir_node *node, ir_nodeset_t *nodeset)
426 /* You should better break out of your loop when hitting the first phi
428 assert(!is_Phi(node) && "liveness_transfer produces invalid results for phi nodes");
430 be_foreach_definition(node, cls, value, req,
431 ir_nodeset_remove(nodeset, value);
434 be_foreach_use(node, cls, in_req, op, op_req,
435 ir_nodeset_insert(nodeset, op);
441 void be_liveness_end_of_block(const be_lv_t *lv,
442 const arch_register_class_t *cls,
443 const ir_node *block, ir_nodeset_t *live)
445 assert(lv->sets_valid && "live sets must be computed");
446 be_lv_foreach_cls(lv, block, be_lv_state_end, cls, node) {
447 ir_nodeset_insert(live, node);
453 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)
455 ir_node *const bl = get_nodes_block(pos);
456 be_liveness_end_of_block(lv, cls, bl, live);
457 sched_foreach_reverse(bl, irn) {
458 be_liveness_transfer(cls, irn, live);
464 static void collect_node(ir_node *irn, void *data)
466 struct obstack *obst = (struct obstack*)data;
467 obstack_ptr_grow(obst, irn);
470 static void be_live_chk_compare(be_lv_t *lv, lv_chk_t *lvc)
472 ir_graph *irg = lv->irg;
481 irg_block_walk_graph(irg, collect_node, NULL, &obst);
482 obstack_ptr_grow(&obst, NULL);
483 blocks = (ir_node**)obstack_finish(&obst);
485 irg_walk_graph(irg, collect_node, NULL, &obst);
486 obstack_ptr_grow(&obst, NULL);
487 nodes = (ir_node**)obstack_finish(&obst);
489 stat_ev_ctx_push("be_lv_chk_compare");
490 for (j = 0; nodes[j]; ++j) {
491 ir_node *irn = nodes[j];
495 for (i = 0; blocks[i]; ++i) {
496 ir_node *bl = blocks[i];
497 int lvr_in = be_is_live_in (lv, bl, irn);
498 int lvr_out = be_is_live_out(lv, bl, irn);
499 int lvr_end = be_is_live_end(lv, bl, irn);
501 int lvc_in = lv_chk_bl_in (lvc, bl, irn);
502 int lvc_out = lv_chk_bl_out(lvc, bl, irn);
503 int lvc_end = lv_chk_bl_end(lvc, bl, irn);
505 if (lvr_in - lvc_in != 0)
506 ir_fprintf(stderr, "live in info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_in, lvc_in);
508 if (lvr_end - lvc_end != 0)
509 ir_fprintf(stderr, "live end info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_end, lvc_end);
511 if (lvr_out - lvc_out != 0)
512 ir_fprintf(stderr, "live out info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_out, lvc_out);
515 stat_ev_ctx_pop("be_lv_chk_compare");
517 obstack_free(&obst, NULL);
520 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_live)
521 void be_init_live(void)
523 (void)be_live_chk_compare;
524 FIRM_DBG_REGISTER(dbg, "firm.be.liveness");