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 */
65 const arch_register_class_t *cls;
66 const arch_env_t *arch_env;
67 const be_chordal_env_t *chordal_env;
70 int spill_cost; /**< the cost of a single spill node */
71 int reload_cost; /**< the cost of a reload node */
72 set *spills; /**< all spill_info_t's, which must be placed */
73 pset *mem_phis; /**< set of all special spilled phis. allocated and freed separately */
75 DEBUG_ONLY(firm_dbg_module_t *dbg;)
79 * Compare two spill infos.
81 static int cmp_spillinfo(const void *x, const void *y, size_t size) {
82 const spill_info_t *xx = x;
83 const spill_info_t *yy = y;
84 return xx->spilled_node != yy->spilled_node;
88 * Returns spill info for a specific value (returns NULL if the info doesn't
91 static spill_info_t *find_spillinfo(const spill_env_t *env, ir_node *value) {
93 int hash = nodeset_hash(value);
95 info.spilled_node = value;
97 return set_find(env->spills, &info, sizeof(info), hash);
101 * Returns spill info for a specific value (the value that is to be spilled)
103 static spill_info_t *get_spillinfo(const spill_env_t *env, ir_node *value) {
104 spill_info_t info, *res;
105 int hash = nodeset_hash(value);
107 info.spilled_node = value;
108 res = set_find(env->spills, &info, sizeof(info), hash);
111 info.reloaders = NULL;
113 info.old_spill = NULL;
114 res = set_insert(env->spills, &info, sizeof(info), hash);
121 /* Sets the debug module of a spill environment. */
122 void be_set_spill_env_dbg_module(spill_env_t *env, firm_dbg_module_t *dbg) {
127 /* Creates a new spill environment. */
128 spill_env_t *be_new_spill_env(const be_chordal_env_t *chordal_env) {
129 spill_env_t *env = xmalloc(sizeof(env[0]));
130 env->spills = new_set(cmp_spillinfo, 1024);
131 env->cls = chordal_env->cls;
132 env->chordal_env = chordal_env;
133 env->birg = chordal_env->birg;
134 env->arch_env = env->chordal_env->birg->main_env->arch_env;
135 env->mem_phis = pset_new_ptr_default();
136 // TODO, ask backend about costs...
138 env->reload_cost = 5;
139 obstack_init(&env->obst);
143 /* Deletes a spill environment. */
144 void be_delete_spill_env(spill_env_t *env) {
145 del_set(env->spills);
146 del_pset(env->mem_phis);
147 obstack_free(&env->obst, NULL);
153 * | _ \| | __ _ ___ ___ | _ \ ___| | ___ __ _ __| |___
154 * | |_) | |/ _` |/ __/ _ \ | |_) / _ \ |/ _ \ / _` |/ _` / __|
155 * | __/| | (_| | (_| __/ | _ < __/ | (_) | (_| | (_| \__ \
156 * |_| |_|\__,_|\___\___| |_| \_\___|_|\___/ \__,_|\__,_|___/
160 void be_add_reload(spill_env_t *env, ir_node *to_spill, ir_node *before) {
164 assert(arch_irn_consider_in_reg_alloc(env->arch_env, env->cls, to_spill));
166 info = get_spillinfo(env, to_spill);
168 if(is_Phi(to_spill)) {
170 // create spillinfos for the phi arguments
171 for(i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
172 ir_node *arg = get_irn_n(to_spill, i);
173 get_spillinfo(env, arg);
177 // hackery... sometimes the morgan algo spilled the value of a phi,
178 // the belady algo decides later to spill the whole phi, then sees the
179 // spill node and adds a reload for that spill node, problem is the
180 // reload gets attach to that same spill (and is totally unnecessary)
181 if(info->old_spill != NULL &&
182 (before == info->old_spill || value_dominates(before, info->old_spill))) {
183 printf("spilledphi hack was needed...\n");
184 before = sched_next(info->old_spill);
189 rel = obstack_alloc(&env->obst, sizeof(rel[0]));
190 rel->reloader = before;
191 rel->next = info->reloaders;
192 info->reloaders = rel;
195 static ir_node *get_reload_insertion_point(ir_node *block, int pos) {
196 ir_node *predblock, *last;
198 /* simply add the reload to the beginning of the block if we only have 1 predecessor
199 * (we don't need to check for phis as there can't be any in a block with only 1 pred)
201 if(get_Block_n_cfgpreds(block) == 1) {
202 assert(!is_Phi(sched_first(block)));
203 return sched_first(block);
206 /* We have to reload the value in pred-block */
207 predblock = get_Block_cfgpred_block(block, pos);
208 last = sched_last(predblock);
210 /* we might have projs and keepanys behind the jump... */
211 while(is_Proj(last) || be_is_Keep(last)) {
212 last = sched_prev(last);
213 assert(!sched_is_end(last));
217 ir_graph *irg = get_irn_irg(block);
218 ir_node *startblock = get_irg_start_block(irg);
220 last = sched_next(last);
221 // last node must be a cfop, only exception is the start block
222 assert(last == startblock);
225 // add the reload before the (cond-)jump
229 void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block, int pos) {
230 ir_node *before = get_reload_insertion_point(block, pos);
231 be_add_reload(env, to_spill, before);
234 void be_spill_phi(spill_env_t *env, ir_node *node) {
238 assert(is_Phi(node));
240 pset_insert_ptr(env->mem_phis, node);
242 // create spillinfos for the phi arguments
243 spill = get_spillinfo(env, node);
244 for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
245 ir_node *arg = get_irn_n(node, i);
246 get_spillinfo(env, arg);
249 // if we had a spill for the phi value before, then remove this spill from
250 // schedule, as we will remove it in the insert spill/reload phase
251 if(spill->spill != NULL && !is_Phi(spill->spill)) {
252 assert(spill->old_spill == NULL);
253 spill->old_spill = spill->spill;
260 * / ___|_ __ ___ __ _| |_ ___ / ___| _ __ (_) | |___
261 * | | | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
262 * | |___| | | __/ (_| | || __/ ___) | |_) | | | \__ \
263 * \____|_| \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
268 * Schedules a node after an instruction. (That is the place after all projs and phis
269 * that are scheduled after the instruction)
270 * This function also skips phi nodes at the beginning of a block
272 static void sched_add_after_insn(ir_node *sched_after, ir_node *node) {
273 ir_node *next = sched_next(sched_after);
274 while(is_Proj(next) || is_Phi(next)) {
275 next = sched_next(next);
277 assert(next != NULL);
279 if(sched_is_end(next)) {
280 sched_add_after(sched_last(get_nodes_block(sched_after)), node);
282 sched_add_before(next, node);
289 * @param senv the spill environment
290 * @param irn the node that should be spilled
291 * @param ctx_irn an user of the spilled node
293 * @return a be_Spill node
295 static void spill_irn(spill_env_t *env, spill_info_t *spillinfo) {
296 ir_node *to_spill = spillinfo->spilled_node;
298 DBG((env->dbg, LEVEL_1, "%+F\n", to_spill));
300 /* Trying to spill an already spilled value, no need for a new spill
301 * node then, we can simply connect to the same one for this reload
303 * (although rematerialization code should handle most of these cases
304 * this can still happen when spilling Phis)
306 if(be_is_Reload(to_spill)) {
307 spillinfo->spill = get_irn_n(to_spill, be_pos_Reload_mem);
311 if (arch_irn_is(env->arch_env, to_spill, dont_spill)) {
312 if (env->chordal_env->opts->vrfy_option == BE_CH_VRFY_WARN)
313 ir_fprintf(stderr, "Verify warning: spilling 'dont_spill' node %+F\n", to_spill);
314 else if (env->chordal_env->opts->vrfy_option == BE_CH_VRFY_ASSERT)
315 assert(0 && "Attempt to spill a node marked 'dont_spill'");
318 spillinfo->spill = be_spill(env->arch_env, to_spill);
319 sched_add_after_insn(to_spill, spillinfo->spill);
322 static void spill_node(spill_env_t *env, spill_info_t *spillinfo);
325 * If the first usage of a Phi result would be out of memory
326 * there is no sense in allocating a register for it.
327 * Thus we spill it and all its operands to the same spill slot.
328 * Therefore the phi/dataB becomes a phi/Memory
330 * @param senv the spill environment
331 * @param phi the Phi node that should be spilled
332 * @param ctx_irn an user of the spilled node
334 static void spill_phi(spill_env_t *env, spill_info_t *spillinfo) {
335 ir_node *phi = spillinfo->spilled_node;
337 int arity = get_irn_arity(phi);
338 ir_node *block = get_nodes_block(phi);
343 /* build a new PhiM */
344 ins = alloca(sizeof(ir_node*) * arity);
345 for(i = 0; i < arity; ++i) {
346 ins[i] = get_irg_bad(env->chordal_env->irg);
348 spillinfo->spill = new_r_Phi(env->chordal_env->irg, block, arity, ins, mode_M);
350 for(i = 0; i < arity; ++i) {
351 ir_node *arg = get_irn_n(phi, i);
352 spill_info_t *arg_info = get_spillinfo(env, arg);
354 spill_node(env, arg_info);
356 set_irn_n(spillinfo->spill, i, arg_info->spill);
359 // rewire reloads from old_spill to phi
360 if(spillinfo->old_spill != NULL) {
361 const ir_edge_t *edge, *next;
362 ir_node *old_spill = spillinfo->old_spill;
364 foreach_out_edge_safe(old_spill, edge, next) {
365 ir_node* reload = get_edge_src_irn(edge);
366 assert(be_is_Reload(reload) || is_Phi(reload));
367 set_irn_n(reload, get_edge_src_pos(edge), spillinfo->spill);
369 set_irn_n(old_spill, be_pos_Spill_val, new_Bad());
370 //sched_remove(old_spill);
371 spillinfo->old_spill = NULL;
378 * @param senv the spill environment
379 * @param to_spill the node that should be spilled
381 static void spill_node(spill_env_t *env, spill_info_t *spillinfo) {
384 // the node should be tagged for spilling already...
385 if(spillinfo->spill != NULL)
388 to_spill = spillinfo->spilled_node;
389 if (is_Phi(to_spill) && pset_find_ptr(env->mem_phis, spillinfo->spilled_node)) {
390 spill_phi(env, spillinfo);
392 spill_irn(env, spillinfo);
399 * | _ \ ___ _ __ ___ __ _| |_ ___ _ __(_) __ _| (_)_______
400 * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_ / _ \
401 * | _ < __/ | | | | | (_| | || __/ | | | (_| | | |/ / __/
402 * |_| \_\___|_| |_| |_|\__,_|\__\___|_| |_|\__,_|_|_/___\___|
407 * Tests whether value @p arg is available before node @p reloader
408 * @returns 1 if value is available, 0 otherwise
410 static int is_value_available(spill_env_t *env, ir_node *arg, ir_node *reloader) {
411 if(is_Unknown(arg) || arg == new_NoMem())
417 if(arg == get_irg_frame(env->chordal_env->irg))
420 // hack for now (happens when command should be inserted at end of block)
421 if(is_Block(reloader)) {
425 /* the following test does not work while spilling,
426 * because the liveness info is not adapted yet to the effects of the
427 * additional spills/reloads.
429 * So we can only do this test for ignore registers (of our register class)
431 if(arch_get_irn_reg_class(env->arch_env, arg, -1) == env->cls
432 && arch_irn_is(env->arch_env, arg, ignore)) {
435 /* we want to remat before the insn reloader
436 * thus an arguments is alive if
437 * - it interferes with the reloaders result
438 * - or it is (last-) used by reloader itself
440 if (values_interfere(env->birg->lv, reloader, arg)) {
444 arity = get_irn_arity(reloader);
445 for (i = 0; i < arity; ++i) {
446 ir_node *rel_arg = get_irn_n(reloader, i);
456 * Checks whether the node can principally be rematerialized
458 static int is_remat_node(spill_env_t *env, ir_node *node) {
459 const arch_env_t *arch_env = env->arch_env;
461 assert(!be_is_Spill(node));
463 if(arch_irn_is(arch_env, node, rematerializable)) {
467 if(be_is_StackParam(node))
474 * Check if a node is rematerializable. This tests for the following conditions:
476 * - The node itself is rematerializable
477 * - All arguments of the node are available or also rematerialisable
478 * - The costs for the rematerialisation operation is less or equal a limit
480 * Returns the costs needed for rematerialisation or something
481 * > REMAT_COST_LIMIT if remat is not possible.
483 static int check_remat_conditions_costs(spill_env_t *env, ir_node *spilled, ir_node *reloader, int parentcosts) {
488 if(!is_remat_node(env, spilled))
489 return REMAT_COST_LIMIT;
491 if(be_is_Reload(spilled)) {
494 costs += arch_get_op_estimated_cost(env->arch_env, spilled);
496 if(parentcosts + costs >= REMAT_COST_LIMIT) {
497 return REMAT_COST_LIMIT;
501 for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
502 ir_node *arg = get_irn_n(spilled, i);
504 if(is_value_available(env, arg, reloader))
507 // we have to rematerialize the argument as well...
509 /* we only support rematerializing 1 argument at the moment,
510 * so that we don't have to care about register pressure
512 return REMAT_COST_LIMIT;
516 costs += check_remat_conditions_costs(env, arg, reloader, parentcosts + costs);
517 if(parentcosts + costs >= REMAT_COST_LIMIT)
518 return REMAT_COST_LIMIT;
524 static int check_remat_conditions(spill_env_t *env, ir_node *spilled, ir_node *reloader) {
525 int costs = check_remat_conditions_costs(env, spilled, reloader, 0);
527 return costs < REMAT_COST_LIMIT;
531 * Re-materialize a node.
533 * @param senv the spill environment
534 * @param spilled the node that was spilled
535 * @param reloader a irn that requires a reload
537 static ir_node *do_remat(spill_env_t *env, ir_node *spilled, ir_node *reloader) {
543 if(is_Block(reloader)) {
546 bl = get_nodes_block(reloader);
549 ins = alloca(get_irn_arity(spilled) * sizeof(ins[0]));
550 for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
551 ir_node *arg = get_irn_n(spilled, i);
553 if(is_value_available(env, arg, reloader)) {
556 ins[i] = do_remat(env, arg, reloader);
560 /* create a copy of the node */
561 res = new_ir_node(get_irn_dbg_info(spilled), env->chordal_env->irg, bl,
563 get_irn_mode(spilled),
564 get_irn_arity(spilled),
566 copy_node_attr(spilled, res);
567 new_backedge_info(res);
569 DBG((env->dbg, LEVEL_1, "Insert remat %+F before reloader %+F\n", res, reloader));
571 /* insert in schedule */
572 sched_add_before(reloader, res);
577 int be_get_reload_costs(spill_env_t *env, ir_node *to_spill, ir_node *before) {
578 spill_info_t *spill_info;
581 // is the node rematerializable?
582 int costs = check_remat_conditions_costs(env, to_spill, before, 0);
583 if(costs < REMAT_COST_LIMIT)
587 // do we already have a spill?
588 spill_info = find_spillinfo(env, to_spill);
589 if(spill_info != NULL && spill_info->spill != NULL)
590 return env->reload_cost;
592 return env->spill_cost + env->reload_cost;
595 int be_get_reload_costs_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block, int pos) {
596 ir_node *before = get_reload_insertion_point(block, pos);
597 return be_get_reload_costs(env, to_spill, before);
602 * |_ _|_ __ ___ ___ _ __| |_ | _ \ ___| | ___ __ _ __| |___
603 * | || '_ \/ __|/ _ \ '__| __| | |_) / _ \ |/ _ \ / _` |/ _` / __|
604 * | || | | \__ \ __/ | | |_ | _ < __/ | (_) | (_| | (_| \__ \
605 * |___|_| |_|___/\___|_| \__| |_| \_\___|_|\___/ \__,_|\__,_|___/
609 void be_insert_spills_reloads(spill_env_t *env) {
610 const arch_env_t *arch_env = env->arch_env;
616 /* process each spilled node */
617 for(si = set_first(env->spills); si; si = set_next(env->spills)) {
619 ir_mode *mode = get_irn_mode(si->spilled_node);
620 pset *values = pset_new_ptr(16);
622 /* go through all reloads for this spill */
623 for(rld = si->reloaders; rld; rld = rld->next) {
626 if (be_do_remats && check_remat_conditions(env, si->spilled_node, rld->reloader)) {
627 new_val = do_remat(env, si->spilled_node, rld->reloader);
630 /* make sure we have a spill */
631 if(si->spill == NULL) {
636 /* create a reload */
637 new_val = be_reload(arch_env, env->cls, rld->reloader, mode, si->spill);
641 DBG((env->dbg, LEVEL_1, " %+F of %+F before %+F\n", new_val, si->spilled_node, rld->reloader));
642 pset_insert_ptr(values, new_val);
645 if(pset_count(values) > 0) {
646 /* introduce copies, rewire the uses */
647 pset_insert_ptr(values, si->spilled_node);
648 be_ssa_constr_set_ignore(env->birg->dom_front, env->birg->lv, values, env->mem_phis);
653 si->reloaders = NULL;
656 if(be_stat_ev_is_active()) {
657 be_stat_ev("spill_spills", spills);
658 be_stat_ev("spill_reloads", reloads);
659 be_stat_ev("spill_remats", remats);
662 be_remove_dead_nodes_from_schedule(env->chordal_env->irg);
663 //be_liveness_recompute(env->birg->lv);
664 be_invalidate_liveness(env->birg);