2 * Author: Daniel Grund, Sebastian Hack, Matthias Braun
4 * Copyright: (c) Universitaet Karlsruhe
5 * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
16 #include "iredges_t.h"
17 #include "irbackedge_t.h"
26 #include "unionfind.h"
30 #include "besched_t.h"
34 #include "bechordal_t.h"
35 #include "bejavacoal.h"
36 #include "benodesets.h"
37 #include "bespilloptions.h"
38 #include "bestatevent.h"
40 // only rematerialise when costs are less than REMAT_COST_LIMIT
41 // TODO determine a good value here...
42 #define REMAT_COST_LIMIT 10
44 typedef struct _reloader_t reloader_t;
49 ir_node *rematted_node;
52 typedef struct _spill_info_t {
53 /** the value that should get spilled */
54 ir_node *spilled_node;
55 /** list of places where the value should get reloaded */
56 reloader_t *reloaders;
58 /** the spill node, or a PhiM node */
60 /** if we had the value of a phi spilled before but not the phi itself then
61 * this field contains the spill for the phi value */
64 /** the register class in which the reload should be placed */
65 const arch_register_class_t *reload_cls;
69 const arch_env_t *arch_env;
73 int spill_cost; /**< the cost of a single spill node */
74 int reload_cost; /**< the cost of a reload node */
75 set *spills; /**< all spill_info_t's, which must be placed */
76 pset *mem_phis; /**< set of all special spilled phis. allocated and freed separately */
78 DEBUG_ONLY(firm_dbg_module_t *dbg;)
82 * Compare two spill infos.
84 static int cmp_spillinfo(const void *x, const void *y, size_t size) {
85 const spill_info_t *xx = x;
86 const spill_info_t *yy = y;
87 return xx->spilled_node != yy->spilled_node;
91 * Returns spill info for a specific value (returns NULL if the info doesn't
94 static spill_info_t *find_spillinfo(const spill_env_t *env, ir_node *value) {
96 int hash = nodeset_hash(value);
98 info.spilled_node = value;
100 return set_find(env->spills, &info, sizeof(info), hash);
104 * Returns spill info for a specific value (the value that is to be spilled)
106 static spill_info_t *get_spillinfo(const spill_env_t *env, ir_node *value) {
107 spill_info_t info, *res;
108 int hash = nodeset_hash(value);
110 info.spilled_node = value;
111 res = set_find(env->spills, &info, sizeof(info), hash);
114 info.reloaders = NULL;
116 info.old_spill = NULL;
117 info.reload_cls = NULL;
118 res = set_insert(env->spills, &info, sizeof(info), hash);
125 /* Sets the debug module of a spill environment. */
126 void be_set_spill_env_dbg_module(spill_env_t *env, firm_dbg_module_t *dbg) {
131 /* Creates a new spill environment. */
132 spill_env_t *be_new_spill_env(be_irg_t *birg) {
133 spill_env_t *env = xmalloc(sizeof(env[0]));
134 env->spills = new_set(cmp_spillinfo, 1024);
135 env->irg = be_get_birg_irg(birg);
137 env->arch_env = birg->main_env->arch_env;
138 env->mem_phis = pset_new_ptr_default();
139 // TODO, ask backend about costs..., or even ask backend whether we should
142 env->reload_cost = 5;
143 obstack_init(&env->obst);
147 /* Deletes a spill environment. */
148 void be_delete_spill_env(spill_env_t *env) {
149 del_set(env->spills);
150 del_pset(env->mem_phis);
151 obstack_free(&env->obst, NULL);
157 * | _ \| | __ _ ___ ___ | _ \ ___| | ___ __ _ __| |___
158 * | |_) | |/ _` |/ __/ _ \ | |_) / _ \ |/ _ \ / _` |/ _` / __|
159 * | __/| | (_| | (_| __/ | _ < __/ | (_) | (_| | (_| \__ \
160 * |_| |_|\__,_|\___\___| |_| \_\___|_|\___/ \__,_|\__,_|___/
164 void be_add_remat(spill_env_t *env, ir_node *to_spill, ir_node *before, ir_node *rematted_node, const arch_register_class_t *reload_cls) {
165 spill_info_t *spill_info;
166 reloader_t *reloader;
168 spill_info = get_spillinfo(env, to_spill);
170 reloader = obstack_alloc(&env->obst, sizeof(reloader[0]));
171 reloader->next = spill_info->reloaders;
172 reloader->reloader = before;
173 reloader->rematted_node = rematted_node;
175 spill_info->reloaders = reloader;
176 assert(spill_info->reload_cls == NULL || spill_info->reload_cls == reload_cls);
177 spill_info->reload_cls = reload_cls;
180 void be_add_reload(spill_env_t *env, ir_node *to_spill, ir_node *before, const arch_register_class_t *reload_cls) {
184 info = get_spillinfo(env, to_spill);
186 if(is_Phi(to_spill)) {
189 /* create spillinfos for the phi arguments */
190 for (i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
191 ir_node *arg = get_irn_n(to_spill, i);
192 get_spillinfo(env, arg);
196 // hackery... sometimes the morgan algo spilled the value of a phi,
197 // the belady algo decides later to spill the whole phi, then sees the
198 // spill node and adds a reload for that spill node, problem is the
199 // reload gets attach to that same spill (and is totally unnecessary)
200 if (info->old_spill != NULL &&
201 (before == info->old_spill || value_dominates(before, info->old_spill))) {
202 printf("spilledphi hack was needed...\n");
203 before = sched_next(info->old_spill);
208 /* put reload into list */
209 rel = obstack_alloc(&env->obst, sizeof(rel[0]));
210 rel->next = info->reloaders;
211 rel->reloader = before;
212 rel->rematted_node = NULL;
214 info->reloaders = rel;
215 assert(info->reload_cls == NULL || info->reload_cls == reload_cls);
216 info->reload_cls = reload_cls;
219 static ir_node *get_reload_insertion_point(ir_node *block, int pos) {
220 ir_node *predblock, *last;
222 /* simply add the reload to the beginning of the block if we only have 1 predecessor
223 * (we don't need to check for phis as there can't be any in a block with only 1 pred)
225 if(get_Block_n_cfgpreds(block) == 1) {
226 assert(!is_Phi(sched_first(block)));
227 return sched_first(block);
230 /* We have to reload the value in pred-block */
231 predblock = get_Block_cfgpred_block(block, pos);
232 last = sched_last(predblock);
234 /* we might have projs and keepanys behind the jump... */
235 while(is_Proj(last) || be_is_Keep(last)) {
236 last = sched_prev(last);
237 assert(!sched_is_end(last));
241 ir_graph *irg = get_irn_irg(block);
242 ir_node *startblock = get_irg_start_block(irg);
244 last = sched_next(last);
245 // last node must be a cfop, only exception is the start block
246 assert(last == startblock);
249 // add the reload before the (cond-)jump
253 void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill,
254 ir_node *block, int pos, const arch_register_class_t *reload_cls)
256 ir_node *before = get_reload_insertion_point(block, pos);
257 be_add_reload(env, to_spill, before, reload_cls);
260 void be_spill_phi(spill_env_t *env, ir_node *node) {
264 assert(is_Phi(node));
266 pset_insert_ptr(env->mem_phis, node);
268 // create spillinfos for the phi arguments
269 spill = get_spillinfo(env, node);
270 for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
271 ir_node *arg = get_irn_n(node, i);
272 get_spillinfo(env, arg);
275 // if we had a spill for the phi value before, then remove this spill from
276 // schedule, as we will remove it in the insert spill/reload phase
277 if(spill->spill != NULL && !is_Phi(spill->spill)) {
278 assert(spill->old_spill == NULL);
279 spill->old_spill = spill->spill;
286 * / ___|_ __ ___ __ _| |_ ___ / ___| _ __ (_) | |___
287 * | | | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
288 * | |___| | | __/ (_| | || __/ ___) | |_) | | | \__ \
289 * \____|_| \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
294 * Schedules a node after an instruction. (That is the place after all projs and phis
295 * that are scheduled after the instruction)
296 * This function also skips phi nodes at the beginning of a block
298 static void sched_add_after_insn(ir_node *sched_after, ir_node *node) {
299 ir_node *next = sched_next(sched_after);
300 while(is_Proj(next) || is_Phi(next)) {
301 next = sched_next(next);
303 assert(next != NULL);
305 if(sched_is_end(next)) {
306 sched_add_after(sched_last(get_nodes_block(sched_after)), node);
308 sched_add_before(next, node);
315 * @param senv the spill environment
316 * @param irn the node that should be spilled
317 * @param ctx_irn an user of the spilled node
319 * @return a be_Spill node
321 static void spill_irn(spill_env_t *env, spill_info_t *spillinfo) {
322 ir_node *to_spill = spillinfo->spilled_node;
324 DBG((env->dbg, LEVEL_1, "%+F\n", to_spill));
326 /* Trying to spill an already spilled value, no need for a new spill
327 * node then, we can simply connect to the same one for this reload
329 * (although rematerialization code should handle most of these cases
330 * this can still happen when spilling Phis)
332 if(be_is_Reload(to_spill)) {
333 spillinfo->spill = get_irn_n(to_spill, be_pos_Reload_mem);
337 if (arch_irn_is(env->arch_env, to_spill, dont_spill)) {
338 assert(0 && "Attempt to spill a node marked 'dont_spill'");
341 spillinfo->spill = be_spill(env->arch_env, to_spill);
342 sched_add_after_insn(to_spill, spillinfo->spill);
345 static void spill_node(spill_env_t *env, spill_info_t *spillinfo);
348 * If the first usage of a Phi result would be out of memory
349 * there is no sense in allocating a register for it.
350 * Thus we spill it and all its operands to the same spill slot.
351 * Therefore the phi/dataB becomes a phi/Memory
353 * @param senv the spill environment
354 * @param phi the Phi node that should be spilled
355 * @param ctx_irn an user of the spilled node
357 static void spill_phi(spill_env_t *env, spill_info_t *spillinfo) {
358 ir_node *phi = spillinfo->spilled_node;
360 int arity = get_irn_arity(phi);
361 ir_node *block = get_nodes_block(phi);
366 /* build a new PhiM */
367 ins = alloca(sizeof(ir_node*) * arity);
368 for(i = 0; i < arity; ++i) {
369 ins[i] = get_irg_bad(env->irg);
371 spillinfo->spill = new_r_Phi(env->irg, block, arity, ins, mode_M);
373 for(i = 0; i < arity; ++i) {
374 ir_node *arg = get_irn_n(phi, i);
375 spill_info_t *arg_info = get_spillinfo(env, arg);
377 spill_node(env, arg_info);
379 set_irn_n(spillinfo->spill, i, arg_info->spill);
382 // rewire reloads from old_spill to phi
383 if(spillinfo->old_spill != NULL) {
384 const ir_edge_t *edge, *next;
385 ir_node *old_spill = spillinfo->old_spill;
387 foreach_out_edge_safe(old_spill, edge, next) {
388 ir_node* reload = get_edge_src_irn(edge);
389 assert(be_is_Reload(reload) || is_Phi(reload));
390 set_irn_n(reload, get_edge_src_pos(edge), spillinfo->spill);
392 set_irn_n(old_spill, be_pos_Spill_val, new_Bad());
393 //sched_remove(old_spill);
394 spillinfo->old_spill = NULL;
401 * @param senv the spill environment
402 * @param to_spill the node that should be spilled
404 static void spill_node(spill_env_t *env, spill_info_t *spillinfo) {
407 // the node should be tagged for spilling already...
408 if(spillinfo->spill != NULL)
411 to_spill = spillinfo->spilled_node;
412 if (is_Phi(to_spill) && pset_find_ptr(env->mem_phis, spillinfo->spilled_node)) {
413 spill_phi(env, spillinfo);
415 spill_irn(env, spillinfo);
422 * | _ \ ___ _ __ ___ __ _| |_ ___ _ __(_) __ _| (_)_______
423 * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_ / _ \
424 * | _ < __/ | | | | | (_| | || __/ | | | (_| | | |/ / __/
425 * |_| \_\___|_| |_| |_|\__,_|\__\___|_| |_|\__,_|_|_/___\___|
430 * Tests whether value @p arg is available before node @p reloader
431 * @returns 1 if value is available, 0 otherwise
433 static int is_value_available(spill_env_t *env, ir_node *arg, ir_node *reloader) {
434 if(is_Unknown(arg) || arg == new_NoMem())
440 if(arg == get_irg_frame(env->irg))
443 // hack for now (happens when command should be inserted at end of block)
444 if(is_Block(reloader)) {
449 * Ignore registers are always available
451 if(arch_irn_is(env->arch_env, arg, ignore)) {
456 /* the following test does not work while spilling,
457 * because the liveness info is not adapted yet to the effects of the
458 * additional spills/reloads.
461 /* we want to remat before the insn reloader
462 * thus an arguments is alive if
463 * - it interferes with the reloaders result
464 * - or it is (last-) used by reloader itself
466 if (values_interfere(env->birg->lv, reloader, arg)) {
470 arity = get_irn_arity(reloader);
471 for (i = 0; i < arity; ++i) {
472 ir_node *rel_arg = get_irn_n(reloader, i);
482 * Checks whether the node can principally be rematerialized
484 static int is_remat_node(spill_env_t *env, ir_node *node) {
485 const arch_env_t *arch_env = env->arch_env;
487 assert(!be_is_Spill(node));
489 if(arch_irn_is(arch_env, node, rematerializable)) {
493 if(be_is_StackParam(node))
500 * Check if a node is rematerializable. This tests for the following conditions:
502 * - The node itself is rematerializable
503 * - All arguments of the node are available or also rematerialisable
504 * - The costs for the rematerialisation operation is less or equal a limit
506 * Returns the costs needed for rematerialisation or something
507 * > REMAT_COST_LIMIT if remat is not possible.
509 static int check_remat_conditions_costs(spill_env_t *env, ir_node *spilled, ir_node *reloader, int parentcosts) {
514 if(!is_remat_node(env, spilled))
515 return REMAT_COST_LIMIT;
517 if(be_is_Reload(spilled)) {
520 costs += arch_get_op_estimated_cost(env->arch_env, spilled);
522 if(parentcosts + costs >= REMAT_COST_LIMIT) {
523 return REMAT_COST_LIMIT;
527 for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
528 ir_node *arg = get_irn_n(spilled, i);
530 if(is_value_available(env, arg, reloader))
533 // we have to rematerialize the argument as well...
535 /* we only support rematerializing 1 argument at the moment,
536 * so that we don't have to care about register pressure
538 return REMAT_COST_LIMIT;
542 costs += check_remat_conditions_costs(env, arg, reloader, parentcosts + costs);
543 if(parentcosts + costs >= REMAT_COST_LIMIT)
544 return REMAT_COST_LIMIT;
550 static int check_remat_conditions(spill_env_t *env, ir_node *spilled, ir_node *reloader) {
551 int costs = check_remat_conditions_costs(env, spilled, reloader, 0);
553 return costs < REMAT_COST_LIMIT;
557 * Re-materialize a node.
559 * @param senv the spill environment
560 * @param spilled the node that was spilled
561 * @param reloader a irn that requires a reload
563 static ir_node *do_remat(spill_env_t *env, ir_node *spilled, ir_node *reloader) {
569 if(is_Block(reloader)) {
572 bl = get_nodes_block(reloader);
575 ins = alloca(get_irn_arity(spilled) * sizeof(ins[0]));
576 for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
577 ir_node *arg = get_irn_n(spilled, i);
579 if(is_value_available(env, arg, reloader)) {
582 ins[i] = do_remat(env, arg, reloader);
586 /* create a copy of the node */
587 res = new_ir_node(get_irn_dbg_info(spilled), env->irg, bl,
589 get_irn_mode(spilled),
590 get_irn_arity(spilled),
592 copy_node_attr(spilled, res);
593 new_backedge_info(res);
596 DBG((env->dbg, LEVEL_1, "Insert remat %+F before reloader %+F\n", res, reloader));
598 /* insert in schedule */
599 sched_add_before(reloader, res);
604 int be_get_reload_costs(spill_env_t *env, ir_node *to_spill, ir_node *before) {
605 spill_info_t *spill_info;
608 // is the node rematerializable?
609 int costs = check_remat_conditions_costs(env, to_spill, before, 0);
610 if(costs < REMAT_COST_LIMIT)
614 // do we already have a spill?
615 spill_info = find_spillinfo(env, to_spill);
616 if(spill_info != NULL && spill_info->spill != NULL)
617 return env->reload_cost;
619 return env->spill_cost + env->reload_cost;
622 int be_get_reload_costs_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block, int pos) {
623 ir_node *before = get_reload_insertion_point(block, pos);
624 return be_get_reload_costs(env, to_spill, before);
629 * |_ _|_ __ ___ ___ _ __| |_ | _ \ ___| | ___ __ _ __| |___
630 * | || '_ \/ __|/ _ \ '__| __| | |_) / _ \ |/ _ \ / _` |/ _` / __|
631 * | || | | \__ \ __/ | | |_ | _ < __/ | (_) | (_| | (_| \__ \
632 * |___|_| |_|___/\___|_| \__| |_| \_\___|_|\___/ \__,_|\__,_|___/
636 void be_insert_spills_reloads(spill_env_t *env) {
637 const arch_env_t *arch_env = env->arch_env;
643 /* process each spilled node */
644 for (si = set_first(env->spills); si; si = set_next(env->spills)) {
646 ir_mode *mode = get_irn_mode(si->spilled_node);
647 pset *values = pset_new_ptr(16);
649 /* go through all reloads for this spill */
650 for (rld = si->reloaders; rld; rld = rld->next) {
653 if(rld->rematted_node != NULL) {
654 new_val = rld->rematted_node;
656 sched_add_before(rld->reloader, new_val);
657 } else if (be_do_remats && check_remat_conditions(env, si->spilled_node, rld->reloader)) {
658 new_val = do_remat(env, si->spilled_node, rld->reloader);
662 /* make sure we have a spill */
663 if (si->spill == NULL) {
668 /* create a reload */
669 new_val = be_reload(arch_env, si->reload_cls, rld->reloader, mode, si->spill);
673 DBG((env->dbg, LEVEL_1, " %+F of %+F before %+F\n", new_val, si->spilled_node, rld->reloader));
674 pset_insert_ptr(values, new_val);
677 if (pset_count(values) > 0) {
678 /* introduce copies, rewire the uses */
679 pset_insert_ptr(values, si->spilled_node);
680 be_ssa_constr_set_ignore(env->birg->dom_front, env->birg->lv, values, env->mem_phis);
685 si->reloaders = NULL;
688 #ifdef FIRM_STATISTICS
689 if (be_stat_ev_is_active()) {
690 be_stat_ev("spill_spills", spills);
691 be_stat_ev("spill_reloads", reloads);
692 be_stat_ev("spill_remats", remats);
694 #endif /* FIRM_STATISTICS */
696 be_remove_dead_nodes_from_schedule(env->irg);
697 //be_liveness_recompute(env->birg->lv);
698 be_invalidate_liveness(env->birg);