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;
51 typedef struct _spill_info_t {
52 /** the value that should get spilled */
53 ir_node *spilled_node;
54 /** list of places where the value should get reloaded */
55 reloader_t *reloaders;
57 /** the spill node, or a PhiM node */
59 /** if we had the value of a phi spilled before but not the phi itself then
60 * this field contains the spill for the phi value */
63 /** the register class in which the reload should be placed */
64 const arch_register_class_t *reload_cls;
68 const arch_register_class_t *cls;
69 const arch_env_t *arch_env;
70 const be_chordal_env_t *chordal_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 res = set_insert(env->spills, &info, sizeof(info), hash);
124 /* Sets the debug module of a spill environment. */
125 void be_set_spill_env_dbg_module(spill_env_t *env, firm_dbg_module_t *dbg) {
130 /* Creates a new spill environment. */
131 spill_env_t *be_new_spill_env(const be_chordal_env_t *chordal_env) {
132 spill_env_t *env = xmalloc(sizeof(env[0]));
133 env->spills = new_set(cmp_spillinfo, 1024);
134 env->cls = chordal_env->cls;
135 env->chordal_env = chordal_env;
136 env->birg = chordal_env->birg;
137 env->arch_env = env->chordal_env->birg->main_env->arch_env;
138 env->mem_phis = pset_new_ptr_default();
139 // TODO, ask backend about costs...
141 env->reload_cost = 5;
142 obstack_init(&env->obst);
146 /* Deletes a spill environment. */
147 void be_delete_spill_env(spill_env_t *env) {
148 del_set(env->spills);
149 del_pset(env->mem_phis);
150 obstack_free(&env->obst, NULL);
156 * | _ \| | __ _ ___ ___ | _ \ ___| | ___ __ _ __| |___
157 * | |_) | |/ _` |/ __/ _ \ | |_) / _ \ |/ _ \ / _` |/ _` / __|
158 * | __/| | (_| | (_| __/ | _ < __/ | (_) | (_| | (_| \__ \
159 * |_| |_|\__,_|\___\___| |_| \_\___|_|\___/ \__,_|\__,_|___/
163 void be_add_reload(spill_env_t *env, ir_node *to_spill, ir_node *before, const arch_register_class_t *reload_cls) {
167 assert(arch_irn_consider_in_reg_alloc(env->arch_env, env->cls, to_spill));
169 info = get_spillinfo(env, to_spill);
171 if(is_Phi(to_spill)) {
174 /* create spillinfos for the phi arguments */
175 for (i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
176 ir_node *arg = get_irn_n(to_spill, i);
177 get_spillinfo(env, arg);
181 // hackery... sometimes the morgan algo spilled the value of a phi,
182 // the belady algo decides later to spill the whole phi, then sees the
183 // spill node and adds a reload for that spill node, problem is the
184 // reload gets attach to that same spill (and is totally unnecessary)
185 if (info->old_spill != NULL &&
186 (before == info->old_spill || value_dominates(before, info->old_spill))) {
187 printf("spilledphi hack was needed...\n");
188 before = sched_next(info->old_spill);
193 /* put reload into list */
194 rel = obstack_alloc(&env->obst, sizeof(rel[0]));
195 rel->reloader = before;
196 rel->next = info->reloaders;
198 info->reloaders = rel;
199 info->reload_cls = reload_cls;
202 static ir_node *get_reload_insertion_point(ir_node *block, int pos) {
203 ir_node *predblock, *last;
205 /* simply add the reload to the beginning of the block if we only have 1 predecessor
206 * (we don't need to check for phis as there can't be any in a block with only 1 pred)
208 if(get_Block_n_cfgpreds(block) == 1) {
209 assert(!is_Phi(sched_first(block)));
210 return sched_first(block);
213 /* We have to reload the value in pred-block */
214 predblock = get_Block_cfgpred_block(block, pos);
215 last = sched_last(predblock);
217 /* we might have projs and keepanys behind the jump... */
218 while(is_Proj(last) || be_is_Keep(last)) {
219 last = sched_prev(last);
220 assert(!sched_is_end(last));
224 ir_graph *irg = get_irn_irg(block);
225 ir_node *startblock = get_irg_start_block(irg);
227 last = sched_next(last);
228 // last node must be a cfop, only exception is the start block
229 assert(last == startblock);
232 // add the reload before the (cond-)jump
236 void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill,
237 ir_node *block, int pos, const arch_register_class_t *reload_cls)
239 ir_node *before = get_reload_insertion_point(block, pos);
240 be_add_reload(env, to_spill, before, reload_cls);
243 void be_spill_phi(spill_env_t *env, ir_node *node) {
247 assert(is_Phi(node));
249 pset_insert_ptr(env->mem_phis, node);
251 // create spillinfos for the phi arguments
252 spill = get_spillinfo(env, node);
253 for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
254 ir_node *arg = get_irn_n(node, i);
255 get_spillinfo(env, arg);
258 // if we had a spill for the phi value before, then remove this spill from
259 // schedule, as we will remove it in the insert spill/reload phase
260 if(spill->spill != NULL && !is_Phi(spill->spill)) {
261 assert(spill->old_spill == NULL);
262 spill->old_spill = spill->spill;
269 * / ___|_ __ ___ __ _| |_ ___ / ___| _ __ (_) | |___
270 * | | | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
271 * | |___| | | __/ (_| | || __/ ___) | |_) | | | \__ \
272 * \____|_| \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
277 * Schedules a node after an instruction. (That is the place after all projs and phis
278 * that are scheduled after the instruction)
279 * This function also skips phi nodes at the beginning of a block
281 static void sched_add_after_insn(ir_node *sched_after, ir_node *node) {
282 ir_node *next = sched_next(sched_after);
283 while(is_Proj(next) || is_Phi(next)) {
284 next = sched_next(next);
286 assert(next != NULL);
288 if(sched_is_end(next)) {
289 sched_add_after(sched_last(get_nodes_block(sched_after)), node);
291 sched_add_before(next, node);
298 * @param senv the spill environment
299 * @param irn the node that should be spilled
300 * @param ctx_irn an user of the spilled node
302 * @return a be_Spill node
304 static void spill_irn(spill_env_t *env, spill_info_t *spillinfo) {
305 ir_node *to_spill = spillinfo->spilled_node;
307 DBG((env->dbg, LEVEL_1, "%+F\n", to_spill));
309 /* Trying to spill an already spilled value, no need for a new spill
310 * node then, we can simply connect to the same one for this reload
312 * (although rematerialization code should handle most of these cases
313 * this can still happen when spilling Phis)
315 if(be_is_Reload(to_spill)) {
316 spillinfo->spill = get_irn_n(to_spill, be_pos_Reload_mem);
320 if (arch_irn_is(env->arch_env, to_spill, dont_spill)) {
321 if (env->chordal_env->opts->vrfy_option == BE_CH_VRFY_WARN)
322 ir_fprintf(stderr, "Verify warning: spilling 'dont_spill' node %+F\n", to_spill);
323 else if (env->chordal_env->opts->vrfy_option == BE_CH_VRFY_ASSERT)
324 assert(0 && "Attempt to spill a node marked 'dont_spill'");
327 spillinfo->spill = be_spill(env->arch_env, to_spill);
328 sched_add_after_insn(to_spill, spillinfo->spill);
331 static void spill_node(spill_env_t *env, spill_info_t *spillinfo);
334 * If the first usage of a Phi result would be out of memory
335 * there is no sense in allocating a register for it.
336 * Thus we spill it and all its operands to the same spill slot.
337 * Therefore the phi/dataB becomes a phi/Memory
339 * @param senv the spill environment
340 * @param phi the Phi node that should be spilled
341 * @param ctx_irn an user of the spilled node
343 static void spill_phi(spill_env_t *env, spill_info_t *spillinfo) {
344 ir_node *phi = spillinfo->spilled_node;
346 int arity = get_irn_arity(phi);
347 ir_node *block = get_nodes_block(phi);
352 /* build a new PhiM */
353 ins = alloca(sizeof(ir_node*) * arity);
354 for(i = 0; i < arity; ++i) {
355 ins[i] = get_irg_bad(env->chordal_env->irg);
357 spillinfo->spill = new_r_Phi(env->chordal_env->irg, block, arity, ins, mode_M);
359 for(i = 0; i < arity; ++i) {
360 ir_node *arg = get_irn_n(phi, i);
361 spill_info_t *arg_info = get_spillinfo(env, arg);
363 spill_node(env, arg_info);
365 set_irn_n(spillinfo->spill, i, arg_info->spill);
368 // rewire reloads from old_spill to phi
369 if(spillinfo->old_spill != NULL) {
370 const ir_edge_t *edge, *next;
371 ir_node *old_spill = spillinfo->old_spill;
373 foreach_out_edge_safe(old_spill, edge, next) {
374 ir_node* reload = get_edge_src_irn(edge);
375 assert(be_is_Reload(reload) || is_Phi(reload));
376 set_irn_n(reload, get_edge_src_pos(edge), spillinfo->spill);
378 set_irn_n(old_spill, be_pos_Spill_val, new_Bad());
379 //sched_remove(old_spill);
380 spillinfo->old_spill = NULL;
387 * @param senv the spill environment
388 * @param to_spill the node that should be spilled
390 static void spill_node(spill_env_t *env, spill_info_t *spillinfo) {
393 // the node should be tagged for spilling already...
394 if(spillinfo->spill != NULL)
397 to_spill = spillinfo->spilled_node;
398 if (is_Phi(to_spill) && pset_find_ptr(env->mem_phis, spillinfo->spilled_node)) {
399 spill_phi(env, spillinfo);
401 spill_irn(env, spillinfo);
408 * | _ \ ___ _ __ ___ __ _| |_ ___ _ __(_) __ _| (_)_______
409 * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_ / _ \
410 * | _ < __/ | | | | | (_| | || __/ | | | (_| | | |/ / __/
411 * |_| \_\___|_| |_| |_|\__,_|\__\___|_| |_|\__,_|_|_/___\___|
416 * Tests whether value @p arg is available before node @p reloader
417 * @returns 1 if value is available, 0 otherwise
419 static int is_value_available(spill_env_t *env, ir_node *arg, ir_node *reloader) {
420 if(is_Unknown(arg) || arg == new_NoMem())
426 if(arg == get_irg_frame(env->chordal_env->irg))
429 // hack for now (happens when command should be inserted at end of block)
430 if(is_Block(reloader)) {
434 /* the following test does not work while spilling,
435 * because the liveness info is not adapted yet to the effects of the
436 * additional spills/reloads.
438 * So we can only do this test for ignore registers (of our register class)
440 if(arch_get_irn_reg_class(env->arch_env, arg, -1) == env->cls
441 && arch_irn_is(env->arch_env, arg, ignore)) {
444 /* we want to remat before the insn reloader
445 * thus an arguments is alive if
446 * - it interferes with the reloaders result
447 * - or it is (last-) used by reloader itself
449 if (values_interfere(env->birg->lv, reloader, arg)) {
453 arity = get_irn_arity(reloader);
454 for (i = 0; i < arity; ++i) {
455 ir_node *rel_arg = get_irn_n(reloader, i);
465 * Checks whether the node can principally be rematerialized
467 static int is_remat_node(spill_env_t *env, ir_node *node) {
468 const arch_env_t *arch_env = env->arch_env;
470 assert(!be_is_Spill(node));
472 if(arch_irn_is(arch_env, node, rematerializable)) {
476 if(be_is_StackParam(node))
483 * Check if a node is rematerializable. This tests for the following conditions:
485 * - The node itself is rematerializable
486 * - All arguments of the node are available or also rematerialisable
487 * - The costs for the rematerialisation operation is less or equal a limit
489 * Returns the costs needed for rematerialisation or something
490 * > REMAT_COST_LIMIT if remat is not possible.
492 static int check_remat_conditions_costs(spill_env_t *env, ir_node *spilled, ir_node *reloader, int parentcosts) {
497 if(!is_remat_node(env, spilled))
498 return REMAT_COST_LIMIT;
500 if(be_is_Reload(spilled)) {
503 costs += arch_get_op_estimated_cost(env->arch_env, spilled);
505 if(parentcosts + costs >= REMAT_COST_LIMIT) {
506 return REMAT_COST_LIMIT;
510 for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
511 ir_node *arg = get_irn_n(spilled, i);
513 if(is_value_available(env, arg, reloader))
516 // we have to rematerialize the argument as well...
518 /* we only support rematerializing 1 argument at the moment,
519 * so that we don't have to care about register pressure
521 return REMAT_COST_LIMIT;
525 costs += check_remat_conditions_costs(env, arg, reloader, parentcosts + costs);
526 if(parentcosts + costs >= REMAT_COST_LIMIT)
527 return REMAT_COST_LIMIT;
533 static int check_remat_conditions(spill_env_t *env, ir_node *spilled, ir_node *reloader) {
534 int costs = check_remat_conditions_costs(env, spilled, reloader, 0);
536 return costs < REMAT_COST_LIMIT;
540 * Re-materialize a node.
542 * @param senv the spill environment
543 * @param spilled the node that was spilled
544 * @param reloader a irn that requires a reload
546 static ir_node *do_remat(spill_env_t *env, ir_node *spilled, ir_node *reloader) {
552 if(is_Block(reloader)) {
555 bl = get_nodes_block(reloader);
558 ins = alloca(get_irn_arity(spilled) * sizeof(ins[0]));
559 for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
560 ir_node *arg = get_irn_n(spilled, i);
562 if(is_value_available(env, arg, reloader)) {
565 ins[i] = do_remat(env, arg, reloader);
569 /* create a copy of the node */
570 res = new_ir_node(get_irn_dbg_info(spilled), env->chordal_env->irg, bl,
572 get_irn_mode(spilled),
573 get_irn_arity(spilled),
575 copy_node_attr(spilled, res);
576 new_backedge_info(res);
578 DBG((env->dbg, LEVEL_1, "Insert remat %+F before reloader %+F\n", res, reloader));
580 /* insert in schedule */
581 sched_add_before(reloader, res);
586 int be_get_reload_costs(spill_env_t *env, ir_node *to_spill, ir_node *before) {
587 spill_info_t *spill_info;
590 // is the node rematerializable?
591 int costs = check_remat_conditions_costs(env, to_spill, before, 0);
592 if(costs < REMAT_COST_LIMIT)
596 // do we already have a spill?
597 spill_info = find_spillinfo(env, to_spill);
598 if(spill_info != NULL && spill_info->spill != NULL)
599 return env->reload_cost;
601 return env->spill_cost + env->reload_cost;
604 int be_get_reload_costs_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block, int pos) {
605 ir_node *before = get_reload_insertion_point(block, pos);
606 return be_get_reload_costs(env, to_spill, before);
611 * |_ _|_ __ ___ ___ _ __| |_ | _ \ ___| | ___ __ _ __| |___
612 * | || '_ \/ __|/ _ \ '__| __| | |_) / _ \ |/ _ \ / _` |/ _` / __|
613 * | || | | \__ \ __/ | | |_ | _ < __/ | (_) | (_| | (_| \__ \
614 * |___|_| |_|___/\___|_| \__| |_| \_\___|_|\___/ \__,_|\__,_|___/
618 void be_insert_spills_reloads(spill_env_t *env) {
619 const arch_env_t *arch_env = env->arch_env;
625 /* process each spilled node */
626 for (si = set_first(env->spills); si; si = set_next(env->spills)) {
628 ir_mode *mode = get_irn_mode(si->spilled_node);
629 pset *values = pset_new_ptr(16);
631 /* go through all reloads for this spill */
632 for (rld = si->reloaders; rld; rld = rld->next) {
635 if (be_do_remats && check_remat_conditions(env, si->spilled_node, rld->reloader)) {
636 new_val = do_remat(env, si->spilled_node, rld->reloader);
640 /* make sure we have a spill */
641 if (si->spill == NULL) {
646 /* create a reload */
647 new_val = be_reload(arch_env, si->reload_cls, rld->reloader, mode, si->spill);
651 DBG((env->dbg, LEVEL_1, " %+F of %+F before %+F\n", new_val, si->spilled_node, rld->reloader));
652 pset_insert_ptr(values, new_val);
655 if (pset_count(values) > 0) {
656 /* introduce copies, rewire the uses */
657 pset_insert_ptr(values, si->spilled_node);
658 be_ssa_constr_set_ignore(env->birg->dom_front, env->birg->lv, values, env->mem_phis);
663 si->reloaders = NULL;
666 #ifdef FIRM_STATISTICS
667 if (be_stat_ev_is_active()) {
668 be_stat_ev("spill_spills", spills);
669 be_stat_ev("spill_reloads", reloads);
670 be_stat_ev("spill_remats", remats);
672 #endif /* FIRM_STATISTICS */
674 be_remove_dead_nodes_from_schedule(env->chordal_env->irg);
675 //be_liveness_recompute(env->birg->lv);
676 be_invalidate_liveness(env->birg);