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 be_lv_t *lv; /**< The liveness object. */
209 ir_node *def; /**< The node (value). */
210 ir_node *def_block; /**< The block of def. */
214 * Mark a node (value) live out at a certain block. Do this also
215 * transitively, i.e. if the block is not the block of the value's
216 * definition, all predecessors are also marked live.
217 * @param block The block to mark the value live out of.
218 * @param state The liveness bits to set, either end or end+out.
220 static void live_end_at_block(ir_node *const block, be_lv_state_t const state)
222 be_lv_info_node_t *const n = be_lv_get_or_set(re.lv, block, re.def);
223 be_lv_state_t const before = n->flags;
225 assert(state == be_lv_state_end || state == (be_lv_state_end | be_lv_state_out));
226 DBG((dbg, LEVEL_2, "marking %+F live %s at %+F\n", re.def, state & be_lv_state_out ? "end+out" : "end", block));
229 /* There is no need to recurse further, if we where here before (i.e., any
230 * live state bits were set before). */
231 if (before != be_lv_state_none)
234 /* Stop going up further, if this is the block of the definition. */
235 if (re.def_block == block)
238 DBG((dbg, LEVEL_2, "marking %+F live in at %+F\n", re.def, block));
239 n->flags |= be_lv_state_in;
241 for (int i = get_Block_n_cfgpreds(block); i-- != 0;) {
242 ir_node *const pred_block = get_Block_cfgpred_block(block, i);
243 live_end_at_block(pred_block, be_lv_state_end | be_lv_state_out);
247 typedef struct lv_remove_walker_t {
250 } lv_remove_walker_t;
254 * Liveness analysis for a value.
255 * Compute the set of all blocks a value is live in.
256 * @param irn The node (value).
258 static void liveness_for_node(ir_node *irn)
260 ir_node *const def_block = get_nodes_block(irn);
263 re.def_block = def_block;
265 /* Go over all uses of the value */
266 foreach_out_edge(irn, edge) {
267 ir_node *use = edge->src;
270 DBG((dbg, LEVEL_4, "%+F: use at %+F, pos %d in %+F\n", irn, use, edge->pos, get_block(use)));
271 assert(get_irn_n(use, edge->pos) == irn);
274 * If the usage is no data node, skip this use, since it does not
275 * affect the liveness of the node.
277 if (!is_liveness_node(use))
280 /* Get the block where the usage is in. */
281 use_block = get_nodes_block(use);
284 * If the use is a phi function, determine the corresponding block
285 * through which the value reaches the phi function and mark the
286 * value as live out of that block.
289 ir_node *pred_block = get_Block_cfgpred_block(use_block, edge->pos);
290 live_end_at_block(pred_block, be_lv_state_end);
294 * Else, the value is live in at this block. Mark it and call live
295 * out on the predecessors.
297 else if (def_block != use_block) {
300 be_lv_info_node_t *const n = be_lv_get_or_set(re.lv, use_block, irn);
301 DBG((dbg, LEVEL_2, "marking %+F live in at %+F\n", irn, use_block));
302 n->flags |= be_lv_state_in;
304 for (i = get_Block_n_cfgpreds(use_block) - 1; i >= 0; --i) {
305 ir_node *pred_block = get_Block_cfgpred_block(use_block, i);
306 live_end_at_block(pred_block, be_lv_state_end | be_lv_state_out);
312 static void lv_remove_irn_walker(ir_node *bl, void *data)
314 lv_remove_walker_t *w = (lv_remove_walker_t*)data;
315 be_lv_remove(w->lv, bl, w->irn);
319 * Walker, collect all nodes for which we want calculate liveness info
322 static void collect_liveness_nodes(ir_node *irn, void *data)
324 ir_node **nodes = (ir_node**)data;
325 if (is_liveness_node(irn))
326 nodes[get_irn_idx(irn)] = irn;
329 void be_liveness_compute_sets(be_lv_t *lv)
337 be_timer_push(T_LIVE);
338 ir_nodehashmap_init(&lv->map);
339 obstack_init(&lv->obst);
341 n = get_irg_last_idx(lv->irg);
342 ir_node **const nodes = NEW_ARR_FZ(ir_node*, n);
344 /* inserting the variables sorted by their ID is probably
345 * more efficient since the binary sorted set insertion
346 * will not need to move around the data. */
347 irg_walk_graph(lv->irg, NULL, collect_liveness_nodes, nodes);
351 for (i = 0; i < n; ++i) {
352 if (nodes[i] != NULL)
353 liveness_for_node(nodes[i]);
358 be_timer_pop(T_LIVE);
360 lv->sets_valid = true;
363 void be_liveness_compute_chk(be_lv_t *lv)
367 lv->lvc = lv_chk_new(lv->irg);
370 void be_liveness_invalidate_sets(be_lv_t *lv)
374 obstack_free(&lv->obst, NULL);
375 ir_nodehashmap_destroy(&lv->map);
376 lv->sets_valid = false;
379 void be_liveness_invalidate_chk(be_lv_t *lv)
381 be_liveness_invalidate_sets(lv);
385 lv_chk_free(lv->lvc);
389 be_lv_t *be_liveness_new(ir_graph *irg)
391 be_lv_t *lv = XMALLOCZ(be_lv_t);
398 void be_liveness_free(be_lv_t *lv)
400 be_liveness_invalidate_sets(lv);
401 be_liveness_invalidate_chk(lv);
406 void be_liveness_remove(be_lv_t *lv, const ir_node *irn)
408 if (lv->sets_valid) {
409 lv_remove_walker_t w;
412 * Removes a single irn from the liveness information.
413 * Since an irn can only be live at blocks dominated by the block of its
414 * definition, we only have to process that dominance subtree.
418 dom_tree_walk(get_nodes_block(irn), lv_remove_irn_walker, NULL, &w);
422 void be_liveness_introduce(be_lv_t *lv, ir_node *irn)
424 /* Don't compute liveness information for non-data nodes. */
425 if (lv->sets_valid && is_liveness_node(irn)) {
427 liveness_for_node(irn);
431 void be_liveness_update(be_lv_t *lv, ir_node *irn)
433 be_liveness_remove(lv, irn);
434 be_liveness_introduce(lv, irn);
437 void be_liveness_transfer(const arch_register_class_t *cls,
438 ir_node *node, ir_nodeset_t *nodeset)
440 /* You should better break out of your loop when hitting the first phi
442 assert(!is_Phi(node) && "liveness_transfer produces invalid results for phi nodes");
444 be_foreach_definition(node, cls, value, req,
445 ir_nodeset_remove(nodeset, value);
448 be_foreach_use(node, cls, in_req, op, op_req,
449 ir_nodeset_insert(nodeset, op);
455 void be_liveness_end_of_block(const be_lv_t *lv,
456 const arch_register_class_t *cls,
457 const ir_node *block, ir_nodeset_t *live)
459 assert(lv->sets_valid && "live sets must be computed");
460 be_lv_foreach_cls(lv, block, be_lv_state_end, cls, node) {
461 ir_nodeset_insert(live, node);
467 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)
469 ir_node const *const bl = get_nodes_block(pos);
470 be_liveness_end_of_block(lv, cls, bl, live);
471 sched_foreach_reverse(bl, irn) {
472 be_liveness_transfer(cls, irn, live);
478 static void collect_node(ir_node *irn, void *data)
480 struct obstack *obst = (struct obstack*)data;
481 obstack_ptr_grow(obst, irn);
484 static void be_live_chk_compare(be_lv_t *lv, lv_chk_t *lvc)
486 ir_graph *irg = lv->irg;
495 irg_block_walk_graph(irg, collect_node, NULL, &obst);
496 obstack_ptr_grow(&obst, NULL);
497 blocks = (ir_node**)obstack_finish(&obst);
499 irg_walk_graph(irg, collect_node, NULL, &obst);
500 obstack_ptr_grow(&obst, NULL);
501 nodes = (ir_node**)obstack_finish(&obst);
503 stat_ev_ctx_push("be_lv_chk_compare");
504 for (j = 0; nodes[j]; ++j) {
505 ir_node *irn = nodes[j];
509 for (i = 0; blocks[i]; ++i) {
510 ir_node *bl = blocks[i];
511 int lvr_in = be_is_live_in (lv, bl, irn);
512 int lvr_out = be_is_live_out(lv, bl, irn);
513 int lvr_end = be_is_live_end(lv, bl, irn);
515 int lvc_in = lv_chk_bl_in (lvc, bl, irn);
516 int lvc_out = lv_chk_bl_out(lvc, bl, irn);
517 int lvc_end = lv_chk_bl_end(lvc, bl, irn);
519 if (lvr_in - lvc_in != 0)
520 ir_fprintf(stderr, "live in info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_in, lvc_in);
522 if (lvr_end - lvc_end != 0)
523 ir_fprintf(stderr, "live end info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_end, lvc_end);
525 if (lvr_out - lvc_out != 0)
526 ir_fprintf(stderr, "live out info for %+F at %+F differs: nml: %d, chk: %d\n", irn, bl, lvr_out, lvc_out);
529 stat_ev_ctx_pop("be_lv_chk_compare");
531 obstack_free(&obst, NULL);
534 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_live)
535 void be_init_live(void)
537 (void)be_live_chk_compare;
538 FIRM_DBG_REGISTER(dbg, "firm.be.liveness");