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"
25 #include "unionfind.h"
29 #include "besched_t.h"
33 #include "bechordal_t.h"
34 #include "bejavacoal.h"
36 // only rematerialise when costs are less than REMAT_COST_LIMIT
37 // TODO determine a good value here...
38 #define REMAT_COST_LIMIT 80
40 typedef struct _reloader_t reloader_t;
47 typedef struct _spill_info_t {
48 ir_node *spilled_node;
49 reloader_t *reloaders;
55 const arch_register_class_t *cls;
56 const arch_env_t *arch_env;
57 const be_chordal_env_t *chordal_env;
59 set *spills; /**< all spill_info_t's, which must be placed */
60 pset *mem_phis; /**< set of all special spilled phis. allocated and freed separately */
62 DEBUG_ONLY(firm_dbg_module_t *dbg;)
66 * Compare two spill infos.
68 static int cmp_spillinfo(const void *x, const void *y, size_t size) {
69 const spill_info_t *xx = x;
70 const spill_info_t *yy = y;
71 return xx->spilled_node != yy->spilled_node;
75 * Returns spill info for a specific value (the value that is to be spilled)
77 static spill_info_t *get_spillinfo(const spill_env_t *env, ir_node *value) {
78 spill_info_t info, *res;
79 int hash = HASH_PTR(value);
81 info.spilled_node = value;
82 res = set_find(env->spills, &info, sizeof(info), hash);
85 info.reloaders = NULL;
87 res = set_insert(env->spills, &info, sizeof(info), hash);
94 /* Sets the debug module of a spill environment. */
95 void be_set_spill_env_dbg_module(spill_env_t *env, firm_dbg_module_t *dbg) {
100 /* Creates a new spill environment. */
101 spill_env_t *be_new_spill_env(const be_chordal_env_t *chordal_env) {
102 spill_env_t *env = xmalloc(sizeof(env[0]));
103 env->spills = new_set(cmp_spillinfo, 1024);
104 env->cls = chordal_env->cls;
105 env->chordal_env = chordal_env;
106 env->arch_env = env->chordal_env->birg->main_env->arch_env;
107 env->mem_phis = pset_new_ptr_default();
108 obstack_init(&env->obst);
112 /* Deletes a spill environment. */
113 void be_delete_spill_env(spill_env_t *env) {
114 del_set(env->spills);
115 del_pset(env->mem_phis);
116 obstack_free(&env->obst, NULL);
122 * | _ \| | __ _ ___ ___ | _ \ ___| | ___ __ _ __| |___
123 * | |_) | |/ _` |/ __/ _ \ | |_) / _ \ |/ _ \ / _` |/ _` / __|
124 * | __/| | (_| | (_| __/ | _ < __/ | (_) | (_| | (_| \__ \
125 * |_| |_|\__,_|\___\___| |_| \_\___|_|\___/ \__,_|\__,_|___/
129 void be_add_reload(spill_env_t *env, ir_node *to_spill, ir_node *before) {
133 assert(sched_is_scheduled(before));
134 assert(arch_irn_consider_in_reg_alloc(env->arch_env, env->cls, to_spill));
136 info = get_spillinfo(env, to_spill);
138 if(is_Phi(to_spill)) {
140 // create spillinfos for the phi arguments
141 for(i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
142 ir_node *arg = get_irn_n(to_spill, i);
143 get_spillinfo(env, arg);
147 rel = obstack_alloc(&env->obst, sizeof(rel[0]));
148 rel->reloader = before;
149 rel->next = info->reloaders;
150 info->reloaders = rel;
151 be_liveness_add_missing(env->chordal_env->lv);
154 void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block, int pos) {
155 ir_node *predblock, *last;
157 /* simply add the reload to the beginning of the block if we only have 1 predecessor
158 * (we don't need to check for phis as there can't be any in a block with only 1 pred)
160 if(get_Block_n_cfgpreds(block) == 1) {
161 assert(!is_Phi(sched_first(block)));
162 be_add_reload(env, to_spill, sched_first(block));
166 /* We have to reload the value in pred-block */
167 predblock = get_Block_cfgpred_block(block, pos);
168 last = sched_last(predblock);
170 /* we might have projs and keepanys behind the jump... */
171 while(is_Proj(last) || be_is_Keep(last)) {
172 last = sched_prev(last);
173 assert(!sched_is_end(last));
175 assert(is_cfop(last));
177 // add the reload before the (cond-)jump
178 be_add_reload(env, to_spill, last);
181 void be_spill_phi(spill_env_t *env, ir_node *node) {
184 assert(is_Phi(node));
186 pset_insert_ptr(env->mem_phis, node);
188 // create spillinfos for the phi arguments
189 get_spillinfo(env, node);
190 for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
191 ir_node *arg = get_irn_n(node, i);
192 get_spillinfo(env, arg);
198 * / ___|_ __ ___ __ _| |_ ___ / ___| _ __ (_) | |___
199 * | | | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
200 * | |___| | | __/ (_| | || __/ ___) | |_) | | | \__ \
201 * \____|_| \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
206 * Schedules a node after an instruction. (That is the place after all projs and phis
207 * that are scheduled after the instruction)
208 * This function also skips phi nodes at the beginning of a block
210 static void sched_add_after_insn(ir_node *sched_after, ir_node *node) {
211 ir_node *next = sched_next(sched_after);
212 while(is_Proj(next) || is_Phi(next)) {
213 next = sched_next(next);
215 assert(next != NULL);
217 if(sched_is_end(next)) {
218 sched_add_after(sched_last(get_nodes_block(sched_after)), node);
220 sched_add_before(next, node);
227 * @param senv the spill environment
228 * @param irn the node that should be spilled
229 * @param ctx_irn an user of the spilled node
231 * @return a be_Spill node
233 static void spill_irn(spill_env_t *env, spill_info_t *spillinfo) {
234 ir_node *to_spill = spillinfo->spilled_node;
236 DBG((env->dbg, LEVEL_1, "%+F\n", to_spill));
238 /* Trying to spill an already spilled value, no need for a new spill
239 * node then, we can simply connect to the same one for this reload
241 * (although rematerialization code should handle most of these cases
242 * this can still happen when spilling Phis)
244 if(be_is_Reload(to_spill)) {
245 spillinfo->spill = get_irn_n(to_spill, be_pos_Reload_mem);
249 if (arch_irn_is(env->arch_env, to_spill, dont_spill)) {
250 if (env->chordal_env->opts->vrfy_option == BE_CH_VRFY_WARN)
251 ir_fprintf(stderr, "Verify warning: spilling 'dont_spill' node %+F\n", to_spill);
252 else if (env->chordal_env->opts->vrfy_option == BE_CH_VRFY_ASSERT)
253 assert(0 && "Attempt to spill a node marked 'dont_spill'");
256 spillinfo->spill = be_spill(env->arch_env, to_spill);
257 sched_add_after_insn(to_spill, spillinfo->spill);
260 static void spill_node(spill_env_t *env, spill_info_t *spillinfo);
263 * If the first usage of a Phi result would be out of memory
264 * there is no sense in allocating a register for it.
265 * Thus we spill it and all its operands to the same spill slot.
266 * Therefore the phi/dataB becomes a phi/Memory
268 * @param senv the spill environment
269 * @param phi the Phi node that should be spilled
270 * @param ctx_irn an user of the spilled node
272 static void spill_phi(spill_env_t *env, spill_info_t *spillinfo) {
273 ir_node *phi = spillinfo->spilled_node;
275 int arity = get_irn_arity(phi);
276 ir_node *block = get_nodes_block(phi);
281 /* build a new PhiM */
282 ins = alloca(sizeof(ir_node*) * arity);
283 for(i = 0; i < arity; ++i) {
284 ins[i] = get_irg_bad(env->chordal_env->irg);
286 spillinfo->spill = new_r_Phi(env->chordal_env->irg, block, arity, ins, mode_M);
288 for(i = 0; i < arity; ++i) {
289 ir_node *arg = get_irn_n(phi, i);
290 spill_info_t *arg_info = get_spillinfo(env, arg);
292 spill_node(env, arg_info);
294 set_irn_n(spillinfo->spill, i, arg_info->spill);
301 * @param senv the spill environment
302 * @param to_spill the node that should be spilled
304 static void spill_node(spill_env_t *env, spill_info_t *spillinfo) {
307 // the node should be tagged for spilling already...
308 if(spillinfo->spill != NULL)
311 to_spill = spillinfo->spilled_node;
312 if (is_Phi(to_spill) && pset_find_ptr(env->mem_phis, spillinfo->spilled_node)) {
313 spill_phi(env, spillinfo);
315 spill_irn(env, spillinfo);
322 * | _ \ ___ _ __ ___ __ _| |_ ___ _ __(_) __ _| (_)_______
323 * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_ / _ \
324 * | _ < __/ | | | | | (_| | || __/ | | | (_| | | |/ / __/
325 * |_| \_\___|_| |_| |_|\__,_|\__\___|_| |_|\__,_|_|_/___\___|
330 * Tests whether value @p arg is available before node @p reloader
331 * @returns 1 if value is available, 0 otherwise
333 static int is_value_available(spill_env_t *env, ir_node *arg, ir_node *reloader) {
334 if(is_Unknown(arg) || arg == new_NoMem())
340 if(arg == get_irg_frame(env->chordal_env->irg))
343 /* the following test does not work while spilling,
344 * because the liveness info is not adapted yet to the effects of the
345 * additional spills/reloads.
347 * So we can only do this test for ignore registers (of our register class)
349 if(arch_get_irn_reg_class(env->arch_env, arg, -1) == env->chordal_env->cls
350 && arch_irn_is(env->arch_env, arg, ignore)) {
353 /* we want to remat before the insn reloader
354 * thus an arguments is alive if
355 * - it interferes with the reloaders result
356 * - or it is (last-) used by reloader itself
358 if (values_interfere(env->chordal_env->lv, reloader, arg)) {
362 arity = get_irn_arity(reloader);
363 for (i = 0; i < arity; ++i) {
364 ir_node *rel_arg = get_irn_n(reloader, i);
374 * Checks whether the node can principally be rematerialized
376 static int is_remat_node(spill_env_t *env, ir_node *node) {
377 const arch_env_t *arch_env = env->arch_env;
379 assert(!be_is_Spill(node));
381 if(be_is_Reload(node))
384 // TODO why does arch_irn_is say rematerializable anyway?
385 if(be_is_Barrier(node))
388 if(arch_irn_is(arch_env, node, rematerializable))
391 if(be_is_StackParam(node))
398 * Check if a node is rematerializable. This tests for the following conditions:
400 * - The node itself is rematerializable
401 * - All arguments of the node are available or also rematerialisable
402 * - The costs for the rematerialisation operation is less or equal a limit
404 * Returns the costs needed for rematerialisation or something
405 * > REMAT_COST_LIMIT if remat is not possible.
407 static int check_remat_conditions_costs(spill_env_t *env, ir_node *spilled, ir_node *reloader, int parentcosts) {
412 if(!is_remat_node(env, spilled))
413 return REMAT_COST_LIMIT;
415 if(be_is_Reload(spilled)) {
418 costs += arch_get_op_estimated_cost(env->arch_env, spilled);
420 if(parentcosts + costs >= REMAT_COST_LIMIT)
421 return REMAT_COST_LIMIT;
424 for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
425 ir_node *arg = get_irn_n(spilled, i);
427 if(is_value_available(env, arg, reloader))
430 // we have to rematerialize the argument as well...
432 /* we only support rematerializing 1 argument at the moment,
433 * so that we don't have to care about register pressure
435 return REMAT_COST_LIMIT;
439 // TODO can we get more accurate costs than +1?
440 costs += check_remat_conditions_costs(env, arg, reloader, parentcosts + costs);
441 if(parentcosts + costs >= REMAT_COST_LIMIT)
442 return REMAT_COST_LIMIT;
448 static int check_remat_conditions(spill_env_t *env, ir_node *spilled, ir_node *reloader) {
449 int costs = check_remat_conditions_costs(env, spilled, reloader, 1);
451 return costs < REMAT_COST_LIMIT;
455 * Re-materialize a node.
457 * @param senv the spill environment
458 * @param spilled the node that was spilled
459 * @param reloader a irn that requires a reload
461 static ir_node *do_remat(spill_env_t *env, ir_node *spilled, ir_node *reloader) {
464 ir_node *bl = get_nodes_block(reloader);
467 ins = alloca(get_irn_arity(spilled) * sizeof(ins[0]));
468 for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
469 ir_node *arg = get_irn_n(spilled, i);
471 if(is_value_available(env, arg, reloader)) {
474 ins[i] = do_remat(env, arg, reloader);
478 /* create a copy of the node */
479 res = new_ir_node(get_irn_dbg_info(spilled), env->chordal_env->irg, bl,
481 get_irn_mode(spilled),
482 get_irn_arity(spilled),
484 copy_node_attr(spilled, res);
486 DBG((env->dbg, LEVEL_1, "Insert remat %+F before reloader %+F\n", res, reloader));
488 /* insert in schedule */
489 assert(!is_Block(reloader));
490 sched_add_before(reloader, res);
497 * |_ _|_ __ ___ ___ _ __| |_ | _ \ ___| | ___ __ _ __| |___
498 * | || '_ \/ __|/ _ \ '__| __| | |_) / _ \ |/ _ \ / _` |/ _` / __|
499 * | || | | \__ \ __/ | | |_ | _ < __/ | (_) | (_| | (_| \__ \
500 * |___|_| |_|___/\___|_| \__| |_| \_\___|_|\___/ \__,_|\__,_|___/
504 void be_insert_spills_reloads(spill_env_t *env) {
505 const arch_env_t *arch_env = env->arch_env;
508 /* process each spilled node */
509 DBG((env->dbg, LEVEL_1, "Insert spills and reloads:\n"));
510 for(si = set_first(env->spills); si; si = set_next(env->spills)) {
512 ir_mode *mode = get_irn_mode(si->spilled_node);
513 pset *values = pset_new_ptr(16);
515 /* go through all reloads for this spill */
516 for(rld = si->reloaders; rld; rld = rld->next) {
519 if (check_remat_conditions(env, si->spilled_node, rld->reloader)) {
520 new_val = do_remat(env, si->spilled_node, rld->reloader);
522 /* make sure we have a spill */
526 new_val = be_reload(arch_env, env->cls, rld->reloader, mode, si->spill);
529 DBG((env->dbg, LEVEL_1, " %+F of %+F before %+F\n", new_val, si->spilled_node, rld->reloader));
530 pset_insert_ptr(values, new_val);
533 if(pset_count(values) > 0) {
534 /* introduce copies, rewire the uses */
535 pset_insert_ptr(values, si->spilled_node);
536 be_ssa_constr_set_ignore(env->chordal_env->dom_front, env->chordal_env->lv, values, env->mem_phis);
542 // reloads are placed now, but we might reuse the spill environment for further spilling decisions
543 del_set(env->spills);
544 env->spills = new_set(cmp_spillinfo, 1024);