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;
159 typedef struct lv_remove_walker_t {
162 } lv_remove_walker_t;
165 * Removes a node from the list of live variables of a block.
167 static void lv_remove_irn_walker(ir_node *const bl, void *const data)
169 lv_remove_walker_t *const w = (lv_remove_walker_t*)data;
170 ir_node const *const irn = w->irn;
171 be_lv_info_t *const irn_live = ir_nodehashmap_get(be_lv_info_t, &w->lv->map, bl);
172 if (irn_live != NULL) {
173 unsigned n = irn_live[0].head.n_members;
174 unsigned pos = _be_liveness_bsearch(irn_live, irn);
175 be_lv_info_t *payload = irn_live + 1;
176 be_lv_info_node_t *res = &payload[pos].node;
178 /* The node is in deed in the block's array. Let's remove it. */
179 if (res->node == irn) {
182 for (i = pos + 1; i < n; ++i)
183 payload[i - 1] = payload[i];
185 payload[n - 1].node.node = NULL;
186 payload[n - 1].node.flags = 0;
188 --irn_live[0].head.n_members;
189 DBG((dbg, LEVEL_3, "\tdeleting %+F from %+F at pos %d\n", irn, bl, pos));
195 be_lv_t *lv; /**< The liveness object. */
196 ir_node *def; /**< The node (value). */
197 ir_node *def_block; /**< The block of def. */
201 * Mark a node (value) live out at a certain block. Do this also
202 * transitively, i.e. if the block is not the block of the value's
203 * definition, all predecessors are also marked live.
204 * @param block The block to mark the value live out of.
205 * @param state The liveness bits to set, either end or end+out.
207 static void live_end_at_block(ir_node *const block, be_lv_state_t const state)
209 be_lv_info_node_t *const n = be_lv_get_or_set(re.lv, block, re.def);
210 be_lv_state_t const before = n->flags;
212 assert(state == be_lv_state_end || state == (be_lv_state_end | be_lv_state_out));
213 DBG((dbg, LEVEL_2, "marking %+F live %s at %+F\n", re.def, state & be_lv_state_out ? "end+out" : "end", block));
216 /* There is no need to recurse further, if we where here before (i.e., any
217 * live state bits were set before). */
218 if (before != be_lv_state_none)
221 /* Stop going up further, if this is the block of the definition. */
222 if (re.def_block == block)
225 DBG((dbg, LEVEL_2, "marking %+F live in at %+F\n", re.def, block));
226 n->flags |= be_lv_state_in;
228 for (int i = get_Block_n_cfgpreds(block); i-- != 0;) {
229 ir_node *const pred_block = get_Block_cfgpred_block(block, i);
230 live_end_at_block(pred_block, be_lv_state_end | be_lv_state_out);
235 * Liveness analysis for a value.
236 * Compute the set of all blocks a value is live in.
237 * @param irn The node (value).
239 static void liveness_for_node(ir_node *irn)
241 ir_node *const def_block = get_nodes_block(irn);
244 re.def_block = def_block;
246 /* Go over all uses of the value */
247 foreach_out_edge(irn, edge) {
248 ir_node *use = edge->src;
251 DBG((dbg, LEVEL_4, "%+F: use at %+F, pos %d in %+F\n", irn, use, edge->pos, get_block(use)));
252 assert(get_irn_n(use, edge->pos) == irn);
255 * If the usage is no data node, skip this use, since it does not
256 * affect the liveness of the node.
258 if (!is_liveness_node(use))
261 /* Get the block where the usage is in. */
262 use_block = get_nodes_block(use);
265 * If the use is a phi function, determine the corresponding block
266 * through which the value reaches the phi function and mark the
267 * value as live out of that block.
270 ir_node *pred_block = get_Block_cfgpred_block(use_block, edge->pos);
271 live_end_at_block(pred_block, be_lv_state_end);
275 * Else, the value is live in at this block. Mark it and call live
276 * out on the predecessors.
278 else if (def_block != use_block) {
281 be_lv_info_node_t *const n = be_lv_get_or_set(re.lv, use_block, irn);
282 DBG((dbg, LEVEL_2, "marking %+F live in at %+F\n", irn, use_block));
283 n->flags |= be_lv_state_in;
285 for (i = get_Block_n_cfgpreds(use_block) - 1; i >= 0; --i) {
286 ir_node *pred_block = get_Block_cfgpred_block(use_block, i);
287 live_end_at_block(pred_block, be_lv_state_end | be_lv_state_out);
294 * Walker, collect all nodes for which we want calculate liveness info
297 static void collect_liveness_nodes(ir_node *irn, void *data)
299 ir_node **nodes = (ir_node**)data;
300 if (is_liveness_node(irn))
301 nodes[get_irn_idx(irn)] = irn;
304 void be_liveness_compute_sets(be_lv_t *lv)
312 be_timer_push(T_LIVE);
313 ir_nodehashmap_init(&lv->map);
314 obstack_init(&lv->obst);
316 n = get_irg_last_idx(lv->irg);
317 ir_node **const nodes = NEW_ARR_FZ(ir_node*, n);
319 /* inserting the variables sorted by their ID is probably
320 * more efficient since the binary sorted set insertion
321 * will not need to move around the data. */
322 irg_walk_graph(lv->irg, NULL, collect_liveness_nodes, nodes);
326 for (i = 0; i < n; ++i) {
327 if (nodes[i] != NULL)
328 liveness_for_node(nodes[i]);
333 be_timer_pop(T_LIVE);
335 lv->sets_valid = true;
338 void be_liveness_compute_chk(be_lv_t *lv)
342 lv->lvc = lv_chk_new(lv->irg);
345 void be_liveness_invalidate_sets(be_lv_t *lv)
349 obstack_free(&lv->obst, NULL);
350 ir_nodehashmap_destroy(&lv->map);
351 lv->sets_valid = false;
354 void be_liveness_invalidate_chk(be_lv_t *lv)
356 be_liveness_invalidate_sets(lv);
360 lv_chk_free(lv->lvc);
364 be_lv_t *be_liveness_new(ir_graph *irg)
366 be_lv_t *lv = XMALLOCZ(be_lv_t);
373 void be_liveness_free(be_lv_t *lv)
375 be_liveness_invalidate_sets(lv);
376 be_liveness_invalidate_chk(lv);
381 void be_liveness_remove(be_lv_t *lv, const ir_node *irn)
383 if (lv->sets_valid) {
384 lv_remove_walker_t w;
387 * Removes a single irn from the liveness information.
388 * Since an irn can only be live at blocks dominated by the block of its
389 * definition, we only have to process that dominance subtree.
393 dom_tree_walk(get_nodes_block(irn), lv_remove_irn_walker, NULL, &w);
397 void be_liveness_introduce(be_lv_t *lv, ir_node *irn)
399 /* Don't compute liveness information for non-data nodes. */
400 if (lv->sets_valid && is_liveness_node(irn)) {
402 liveness_for_node(irn);
406 void be_liveness_update(be_lv_t *lv, ir_node *irn)
408 be_liveness_remove(lv, irn);
409 be_liveness_introduce(lv, irn);
412 void be_liveness_transfer(const arch_register_class_t *cls,
413 ir_node *node, ir_nodeset_t *nodeset)
415 /* You should better break out of your loop when hitting the first phi
417 assert(!is_Phi(node) && "liveness_transfer produces invalid results for phi nodes");
419 be_foreach_definition(node, cls, value, req,
420 ir_nodeset_remove(nodeset, value);
423 be_foreach_use(node, cls, in_req, op, op_req,
424 ir_nodeset_insert(nodeset, op);
430 void be_liveness_end_of_block(const be_lv_t *lv,
431 const arch_register_class_t *cls,
432 const ir_node *block, ir_nodeset_t *live)
434 assert(lv->sets_valid && "live sets must be computed");
435 be_lv_foreach_cls(lv, block, be_lv_state_end, cls, node) {
436 ir_nodeset_insert(live, node);
442 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)
444 ir_node *const bl = get_nodes_block(pos);
445 be_liveness_end_of_block(lv, cls, bl, live);
446 sched_foreach_reverse(bl, irn) {
447 be_liveness_transfer(cls, irn, live);
453 static void collect_node(ir_node *irn, void *data)
455 struct obstack *obst = (struct obstack*)data;
456 obstack_ptr_grow(obst, irn);
459 static void be_live_chk_compare(be_lv_t *lv, lv_chk_t *lvc)
461 ir_graph *irg = lv->irg;
470 irg_block_walk_graph(irg, collect_node, NULL, &obst);
471 obstack_ptr_grow(&obst, NULL);
472 blocks = (ir_node**)obstack_finish(&obst);
474 irg_walk_graph(irg, collect_node, NULL, &obst);
475 obstack_ptr_grow(&obst, NULL);
476 nodes = (ir_node**)obstack_finish(&obst);
478 stat_ev_ctx_push("be_lv_chk_compare");
479 for (j = 0; nodes[j]; ++j) {
480 ir_node *irn = nodes[j];
484 for (i = 0; blocks[i]; ++i) {
485 ir_node *bl = blocks[i];
486 int lvr_in = be_is_live_in (lv, bl, irn);
487 int lvr_out = be_is_live_out(lv, bl, irn);
488 int lvr_end = be_is_live_end(lv, bl, irn);
490 int lvc_in = lv_chk_bl_in (lvc, bl, irn);
491 int lvc_out = lv_chk_bl_out(lvc, bl, irn);
492 int lvc_end = lv_chk_bl_end(lvc, bl, irn);
494 if (lvr_in - lvc_in != 0)
495 ir_fprintf(stderr, "live in info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_in, lvc_in);
497 if (lvr_end - lvc_end != 0)
498 ir_fprintf(stderr, "live end info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_end, lvc_end);
500 if (lvr_out - lvc_out != 0)
501 ir_fprintf(stderr, "live out info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_out, lvc_out);
504 stat_ev_ctx_pop("be_lv_chk_compare");
506 obstack_free(&obst, NULL);
509 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_live)
510 void be_init_live(void)
512 (void)be_live_chk_compare;
513 FIRM_DBG_REGISTER(dbg, "firm.be.liveness");