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_register_class_t *cls;
70 const arch_env_t *arch_env;
71 const be_chordal_env_t *chordal_env;
74 int spill_cost; /**< the cost of a single spill node */
75 int reload_cost; /**< the cost of a reload node */
76 set *spills; /**< all spill_info_t's, which must be placed */
77 pset *mem_phis; /**< set of all special spilled phis. allocated and freed separately */
79 DEBUG_ONLY(firm_dbg_module_t *dbg;)
83 * Compare two spill infos.
85 static int cmp_spillinfo(const void *x, const void *y, size_t size) {
86 const spill_info_t *xx = x;
87 const spill_info_t *yy = y;
88 return xx->spilled_node != yy->spilled_node;
92 * Returns spill info for a specific value (returns NULL if the info doesn't
95 static spill_info_t *find_spillinfo(const spill_env_t *env, ir_node *value) {
97 int hash = nodeset_hash(value);
99 info.spilled_node = value;
101 return set_find(env->spills, &info, sizeof(info), hash);
105 * Returns spill info for a specific value (the value that is to be spilled)
107 static spill_info_t *get_spillinfo(const spill_env_t *env, ir_node *value) {
108 spill_info_t info, *res;
109 int hash = nodeset_hash(value);
111 info.spilled_node = value;
112 res = set_find(env->spills, &info, sizeof(info), hash);
115 info.reloaders = NULL;
117 info.old_spill = NULL;
118 info.reload_cls = NULL;
119 res = set_insert(env->spills, &info, sizeof(info), hash);
126 /* Sets the debug module of a spill environment. */
127 void be_set_spill_env_dbg_module(spill_env_t *env, firm_dbg_module_t *dbg) {
132 /* Creates a new spill environment. */
133 spill_env_t *be_new_spill_env(const be_chordal_env_t *chordal_env) {
134 spill_env_t *env = xmalloc(sizeof(env[0]));
135 env->spills = new_set(cmp_spillinfo, 1024);
136 env->cls = chordal_env->cls;
137 env->chordal_env = chordal_env;
138 env->birg = chordal_env->birg;
139 env->arch_env = env->chordal_env->birg->main_env->arch_env;
140 env->mem_phis = pset_new_ptr_default();
141 // TODO, ask backend about costs...
143 env->reload_cost = 5;
144 obstack_init(&env->obst);
148 /* Deletes a spill environment. */
149 void be_delete_spill_env(spill_env_t *env) {
150 del_set(env->spills);
151 del_pset(env->mem_phis);
152 obstack_free(&env->obst, NULL);
158 * | _ \| | __ _ ___ ___ | _ \ ___| | ___ __ _ __| |___
159 * | |_) | |/ _` |/ __/ _ \ | |_) / _ \ |/ _ \ / _` |/ _` / __|
160 * | __/| | (_| | (_| __/ | _ < __/ | (_) | (_| | (_| \__ \
161 * |_| |_|\__,_|\___\___| |_| \_\___|_|\___/ \__,_|\__,_|___/
165 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) {
166 spill_info_t *spill_info;
167 reloader_t *reloader;
169 spill_info = get_spillinfo(env, to_spill);
171 reloader = obstack_alloc(&env->obst, sizeof(reloader[0]));
172 reloader->next = spill_info->reloaders;
173 reloader->reloader = before;
174 reloader->rematted_node = rematted_node;
176 spill_info->reloaders = reloader;
177 assert(spill_info->reload_cls == NULL || spill_info->reload_cls == reload_cls);
178 spill_info->reload_cls = reload_cls;
181 void be_add_reload(spill_env_t *env, ir_node *to_spill, ir_node *before, const arch_register_class_t *reload_cls) {
185 assert(arch_irn_consider_in_reg_alloc(env->arch_env, env->cls, to_spill));
187 info = get_spillinfo(env, to_spill);
189 if(is_Phi(to_spill)) {
192 /* create spillinfos for the phi arguments */
193 for (i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
194 ir_node *arg = get_irn_n(to_spill, i);
195 get_spillinfo(env, arg);
199 // hackery... sometimes the morgan algo spilled the value of a phi,
200 // the belady algo decides later to spill the whole phi, then sees the
201 // spill node and adds a reload for that spill node, problem is the
202 // reload gets attach to that same spill (and is totally unnecessary)
203 if (info->old_spill != NULL &&
204 (before == info->old_spill || value_dominates(before, info->old_spill))) {
205 printf("spilledphi hack was needed...\n");
206 before = sched_next(info->old_spill);
211 /* put reload into list */
212 rel = obstack_alloc(&env->obst, sizeof(rel[0]));
213 rel->next = info->reloaders;
214 rel->reloader = before;
215 rel->rematted_node = NULL;
217 info->reloaders = rel;
218 assert(info->reload_cls == NULL || info->reload_cls == reload_cls);
219 info->reload_cls = reload_cls;
222 static ir_node *get_reload_insertion_point(ir_node *block, int pos) {
223 ir_node *predblock, *last;
225 /* simply add the reload to the beginning of the block if we only have 1 predecessor
226 * (we don't need to check for phis as there can't be any in a block with only 1 pred)
228 if(get_Block_n_cfgpreds(block) == 1) {
229 assert(!is_Phi(sched_first(block)));
230 return sched_first(block);
233 /* We have to reload the value in pred-block */
234 predblock = get_Block_cfgpred_block(block, pos);
235 last = sched_last(predblock);
237 /* we might have projs and keepanys behind the jump... */
238 while(is_Proj(last) || be_is_Keep(last)) {
239 last = sched_prev(last);
240 assert(!sched_is_end(last));
244 ir_graph *irg = get_irn_irg(block);
245 ir_node *startblock = get_irg_start_block(irg);
247 last = sched_next(last);
248 // last node must be a cfop, only exception is the start block
249 assert(last == startblock);
252 // add the reload before the (cond-)jump
256 void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill,
257 ir_node *block, int pos, const arch_register_class_t *reload_cls)
259 ir_node *before = get_reload_insertion_point(block, pos);
260 be_add_reload(env, to_spill, before, reload_cls);
263 void be_spill_phi(spill_env_t *env, ir_node *node) {
267 assert(is_Phi(node));
269 pset_insert_ptr(env->mem_phis, node);
271 // create spillinfos for the phi arguments
272 spill = get_spillinfo(env, node);
273 for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
274 ir_node *arg = get_irn_n(node, i);
275 get_spillinfo(env, arg);
278 // if we had a spill for the phi value before, then remove this spill from
279 // schedule, as we will remove it in the insert spill/reload phase
280 if(spill->spill != NULL && !is_Phi(spill->spill)) {
281 assert(spill->old_spill == NULL);
282 spill->old_spill = spill->spill;
289 * / ___|_ __ ___ __ _| |_ ___ / ___| _ __ (_) | |___
290 * | | | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
291 * | |___| | | __/ (_| | || __/ ___) | |_) | | | \__ \
292 * \____|_| \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
297 * Schedules a node after an instruction. (That is the place after all projs and phis
298 * that are scheduled after the instruction)
299 * This function also skips phi nodes at the beginning of a block
301 static void sched_add_after_insn(ir_node *sched_after, ir_node *node) {
302 ir_node *next = sched_next(sched_after);
303 while(is_Proj(next) || is_Phi(next)) {
304 next = sched_next(next);
306 assert(next != NULL);
308 if(sched_is_end(next)) {
309 sched_add_after(sched_last(get_nodes_block(sched_after)), node);
311 sched_add_before(next, node);
318 * @param senv the spill environment
319 * @param irn the node that should be spilled
320 * @param ctx_irn an user of the spilled node
322 * @return a be_Spill node
324 static void spill_irn(spill_env_t *env, spill_info_t *spillinfo) {
325 ir_node *to_spill = spillinfo->spilled_node;
327 DBG((env->dbg, LEVEL_1, "%+F\n", to_spill));
329 /* Trying to spill an already spilled value, no need for a new spill
330 * node then, we can simply connect to the same one for this reload
332 * (although rematerialization code should handle most of these cases
333 * this can still happen when spilling Phis)
335 if(be_is_Reload(to_spill)) {
336 spillinfo->spill = get_irn_n(to_spill, be_pos_Reload_mem);
340 if (arch_irn_is(env->arch_env, to_spill, dont_spill)) {
341 if (env->chordal_env->opts->vrfy_option == BE_CH_VRFY_WARN)
342 ir_fprintf(stderr, "Verify warning: spilling 'dont_spill' node %+F\n", to_spill);
343 else if (env->chordal_env->opts->vrfy_option == BE_CH_VRFY_ASSERT)
344 assert(0 && "Attempt to spill a node marked 'dont_spill'");
347 spillinfo->spill = be_spill(env->arch_env, to_spill);
348 sched_add_after_insn(to_spill, spillinfo->spill);
351 static void spill_node(spill_env_t *env, spill_info_t *spillinfo);
354 * If the first usage of a Phi result would be out of memory
355 * there is no sense in allocating a register for it.
356 * Thus we spill it and all its operands to the same spill slot.
357 * Therefore the phi/dataB becomes a phi/Memory
359 * @param senv the spill environment
360 * @param phi the Phi node that should be spilled
361 * @param ctx_irn an user of the spilled node
363 static void spill_phi(spill_env_t *env, spill_info_t *spillinfo) {
364 ir_node *phi = spillinfo->spilled_node;
366 int arity = get_irn_arity(phi);
367 ir_node *block = get_nodes_block(phi);
372 /* build a new PhiM */
373 ins = alloca(sizeof(ir_node*) * arity);
374 for(i = 0; i < arity; ++i) {
375 ins[i] = get_irg_bad(env->chordal_env->irg);
377 spillinfo->spill = new_r_Phi(env->chordal_env->irg, block, arity, ins, mode_M);
379 for(i = 0; i < arity; ++i) {
380 ir_node *arg = get_irn_n(phi, i);
381 spill_info_t *arg_info = get_spillinfo(env, arg);
383 spill_node(env, arg_info);
385 set_irn_n(spillinfo->spill, i, arg_info->spill);
388 // rewire reloads from old_spill to phi
389 if(spillinfo->old_spill != NULL) {
390 const ir_edge_t *edge, *next;
391 ir_node *old_spill = spillinfo->old_spill;
393 foreach_out_edge_safe(old_spill, edge, next) {
394 ir_node* reload = get_edge_src_irn(edge);
395 assert(be_is_Reload(reload) || is_Phi(reload));
396 set_irn_n(reload, get_edge_src_pos(edge), spillinfo->spill);
398 set_irn_n(old_spill, be_pos_Spill_val, new_Bad());
399 //sched_remove(old_spill);
400 spillinfo->old_spill = NULL;
407 * @param senv the spill environment
408 * @param to_spill the node that should be spilled
410 static void spill_node(spill_env_t *env, spill_info_t *spillinfo) {
413 // the node should be tagged for spilling already...
414 if(spillinfo->spill != NULL)
417 to_spill = spillinfo->spilled_node;
418 if (is_Phi(to_spill) && pset_find_ptr(env->mem_phis, spillinfo->spilled_node)) {
419 spill_phi(env, spillinfo);
421 spill_irn(env, spillinfo);
428 * | _ \ ___ _ __ ___ __ _| |_ ___ _ __(_) __ _| (_)_______
429 * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_ / _ \
430 * | _ < __/ | | | | | (_| | || __/ | | | (_| | | |/ / __/
431 * |_| \_\___|_| |_| |_|\__,_|\__\___|_| |_|\__,_|_|_/___\___|
436 * Tests whether value @p arg is available before node @p reloader
437 * @returns 1 if value is available, 0 otherwise
439 static int is_value_available(spill_env_t *env, ir_node *arg, ir_node *reloader) {
440 if(is_Unknown(arg) || arg == new_NoMem())
446 if(arg == get_irg_frame(env->chordal_env->irg))
449 // hack for now (happens when command should be inserted at end of block)
450 if(is_Block(reloader)) {
454 /* the following test does not work while spilling,
455 * because the liveness info is not adapted yet to the effects of the
456 * additional spills/reloads.
458 * So we can only do this test for ignore registers (of our register class)
460 if(arch_get_irn_reg_class(env->arch_env, arg, -1) == env->cls
461 && arch_irn_is(env->arch_env, arg, ignore)) {
464 /* we want to remat before the insn reloader
465 * thus an arguments is alive if
466 * - it interferes with the reloaders result
467 * - or it is (last-) used by reloader itself
469 if (values_interfere(env->birg->lv, reloader, arg)) {
473 arity = get_irn_arity(reloader);
474 for (i = 0; i < arity; ++i) {
475 ir_node *rel_arg = get_irn_n(reloader, i);
485 * Checks whether the node can principally be rematerialized
487 static int is_remat_node(spill_env_t *env, ir_node *node) {
488 const arch_env_t *arch_env = env->arch_env;
490 assert(!be_is_Spill(node));
492 if(arch_irn_is(arch_env, node, rematerializable)) {
496 if(be_is_StackParam(node))
503 * Check if a node is rematerializable. This tests for the following conditions:
505 * - The node itself is rematerializable
506 * - All arguments of the node are available or also rematerialisable
507 * - The costs for the rematerialisation operation is less or equal a limit
509 * Returns the costs needed for rematerialisation or something
510 * > REMAT_COST_LIMIT if remat is not possible.
512 static int check_remat_conditions_costs(spill_env_t *env, ir_node *spilled, ir_node *reloader, int parentcosts) {
517 if(!is_remat_node(env, spilled))
518 return REMAT_COST_LIMIT;
520 if(be_is_Reload(spilled)) {
523 costs += arch_get_op_estimated_cost(env->arch_env, spilled);
525 if(parentcosts + costs >= REMAT_COST_LIMIT) {
526 return REMAT_COST_LIMIT;
530 for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
531 ir_node *arg = get_irn_n(spilled, i);
533 if(is_value_available(env, arg, reloader))
536 // we have to rematerialize the argument as well...
538 /* we only support rematerializing 1 argument at the moment,
539 * so that we don't have to care about register pressure
541 return REMAT_COST_LIMIT;
545 costs += check_remat_conditions_costs(env, arg, reloader, parentcosts + costs);
546 if(parentcosts + costs >= REMAT_COST_LIMIT)
547 return REMAT_COST_LIMIT;
553 static int check_remat_conditions(spill_env_t *env, ir_node *spilled, ir_node *reloader) {
554 int costs = check_remat_conditions_costs(env, spilled, reloader, 0);
556 return costs < REMAT_COST_LIMIT;
560 * Re-materialize a node.
562 * @param senv the spill environment
563 * @param spilled the node that was spilled
564 * @param reloader a irn that requires a reload
566 static ir_node *do_remat(spill_env_t *env, ir_node *spilled, ir_node *reloader) {
572 if(is_Block(reloader)) {
575 bl = get_nodes_block(reloader);
578 ins = alloca(get_irn_arity(spilled) * sizeof(ins[0]));
579 for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
580 ir_node *arg = get_irn_n(spilled, i);
582 if(is_value_available(env, arg, reloader)) {
585 ins[i] = do_remat(env, arg, reloader);
589 /* create a copy of the node */
590 res = new_ir_node(get_irn_dbg_info(spilled), env->chordal_env->irg, bl,
592 get_irn_mode(spilled),
593 get_irn_arity(spilled),
595 copy_node_attr(spilled, res);
596 new_backedge_info(res);
599 DBG((env->dbg, LEVEL_1, "Insert remat %+F before reloader %+F\n", res, reloader));
601 /* insert in schedule */
602 sched_add_before(reloader, res);
607 int be_get_reload_costs(spill_env_t *env, ir_node *to_spill, ir_node *before) {
608 spill_info_t *spill_info;
611 // is the node rematerializable?
612 int costs = check_remat_conditions_costs(env, to_spill, before, 0);
613 if(costs < REMAT_COST_LIMIT)
617 // do we already have a spill?
618 spill_info = find_spillinfo(env, to_spill);
619 if(spill_info != NULL && spill_info->spill != NULL)
620 return env->reload_cost;
622 return env->spill_cost + env->reload_cost;
625 int be_get_reload_costs_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block, int pos) {
626 ir_node *before = get_reload_insertion_point(block, pos);
627 return be_get_reload_costs(env, to_spill, before);
632 * |_ _|_ __ ___ ___ _ __| |_ | _ \ ___| | ___ __ _ __| |___
633 * | || '_ \/ __|/ _ \ '__| __| | |_) / _ \ |/ _ \ / _` |/ _` / __|
634 * | || | | \__ \ __/ | | |_ | _ < __/ | (_) | (_| | (_| \__ \
635 * |___|_| |_|___/\___|_| \__| |_| \_\___|_|\___/ \__,_|\__,_|___/
639 void be_insert_spills_reloads(spill_env_t *env) {
640 const arch_env_t *arch_env = env->arch_env;
646 /* process each spilled node */
647 for (si = set_first(env->spills); si; si = set_next(env->spills)) {
649 ir_mode *mode = get_irn_mode(si->spilled_node);
650 pset *values = pset_new_ptr(16);
652 /* go through all reloads for this spill */
653 for (rld = si->reloaders; rld; rld = rld->next) {
656 if(rld->rematted_node != NULL) {
657 new_val = rld->rematted_node;
659 } else if (be_do_remats && check_remat_conditions(env, si->spilled_node, rld->reloader)) {
660 new_val = do_remat(env, si->spilled_node, rld->reloader);
664 /* make sure we have a spill */
665 if (si->spill == NULL) {
670 /* create a reload */
671 new_val = be_reload(arch_env, si->reload_cls, rld->reloader, mode, si->spill);
675 DBG((env->dbg, LEVEL_1, " %+F of %+F before %+F\n", new_val, si->spilled_node, rld->reloader));
676 pset_insert_ptr(values, new_val);
679 if (pset_count(values) > 0) {
680 /* introduce copies, rewire the uses */
681 pset_insert_ptr(values, si->spilled_node);
682 be_ssa_constr_set_ignore(env->birg->dom_front, env->birg->lv, values, env->mem_phis);
687 si->reloaders = NULL;
690 #ifdef FIRM_STATISTICS
691 if (be_stat_ev_is_active()) {
692 be_stat_ev("spill_spills", spills);
693 be_stat_ev("spill_reloads", reloads);
694 be_stat_ev("spill_remats", remats);
696 #endif /* FIRM_STATISTICS */
698 be_remove_dead_nodes_from_schedule(env->chordal_env->irg);
699 //be_liveness_recompute(env->birg->lv);
700 be_invalidate_liveness(env->birg);