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"
24 #include "unionfind.h"
28 #include "besched_t.h"
32 #include "bechordal_t.h"
33 #include "bejavacoal.h"
35 // only rematerialise when costs are less than REMAT_COST_LIMIT
36 // TODO determine a good value here...
37 #define REMAT_COST_LIMIT 80
39 typedef struct _reloader_t reloader_t;
46 typedef struct _spill_info_t {
47 ir_node *spilled_node;
48 reloader_t *reloaders;
54 const arch_register_class_t *cls;
55 const arch_env_t *arch_env;
56 const be_chordal_env_t *chordal_env;
58 set *spills; /**< all spill_info_t's, which must be placed */
59 pset *mem_phis; /**< set of all special spilled phis. allocated and freed separately */
61 DEBUG_ONLY(firm_dbg_module_t *dbg;)
65 * Compare two spill infos.
67 static int cmp_spillinfo(const void *x, const void *y, size_t size) {
68 const spill_info_t *xx = x;
69 const spill_info_t *yy = y;
70 return xx->spilled_node != yy->spilled_node;
74 * Returns spill info for a specific value (the value that is to be spilled)
76 static spill_info_t *get_spillinfo(const spill_env_t *env, ir_node *value) {
77 spill_info_t info, *res;
78 int hash = HASH_PTR(value);
80 info.spilled_node = value;
81 res = set_find(env->spills, &info, sizeof(info), hash);
84 info.reloaders = NULL;
86 res = set_insert(env->spills, &info, sizeof(info), hash);
93 /* Sets the debug module of a spill environment. */
94 void be_set_spill_env_dbg_module(spill_env_t *env, firm_dbg_module_t *dbg) {
99 /* Creates a new spill environment. */
100 spill_env_t *be_new_spill_env(const be_chordal_env_t *chordal_env) {
101 spill_env_t *env = xmalloc(sizeof(env[0]));
102 env->spills = new_set(cmp_spillinfo, 1024);
103 env->cls = chordal_env->cls;
104 env->chordal_env = chordal_env;
105 env->arch_env = env->chordal_env->birg->main_env->arch_env;
106 env->mem_phis = pset_new_ptr_default();
107 obstack_init(&env->obst);
111 /* Deletes a spill environment. */
112 void be_delete_spill_env(spill_env_t *env) {
113 del_set(env->spills);
114 del_pset(env->mem_phis);
115 obstack_free(&env->obst, NULL);
121 * | _ \| | __ _ ___ ___ | _ \ ___| | ___ __ _ __| |___
122 * | |_) | |/ _` |/ __/ _ \ | |_) / _ \ |/ _ \ / _` |/ _` / __|
123 * | __/| | (_| | (_| __/ | _ < __/ | (_) | (_| | (_| \__ \
124 * |_| |_|\__,_|\___\___| |_| \_\___|_|\___/ \__,_|\__,_|___/
128 void be_add_reload(spill_env_t *env, ir_node *to_spill, ir_node *before) {
132 assert(sched_is_scheduled(before));
133 assert(arch_irn_consider_in_reg_alloc(env->arch_env, env->cls, to_spill));
135 info = get_spillinfo(env, to_spill);
137 if(is_Phi(to_spill)) {
139 // create spillinfos for the phi arguments
140 for(i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
141 ir_node *arg = get_irn_n(to_spill, i);
142 get_spillinfo(env, arg);
146 rel = obstack_alloc(&env->obst, sizeof(rel[0]));
147 rel->reloader = before;
148 rel->next = info->reloaders;
149 info->reloaders = rel;
150 be_liveness_add_missing(env->chordal_env->lv);
153 void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block, int pos) {
154 ir_node *predblock, *last;
156 /* simply add the reload to the beginning of the block if we only have 1 predecessor
157 * (we don't need to check for phis as there can't be any in a block with only 1 pred)
159 if(get_Block_n_cfgpreds(block) == 1) {
160 assert(!is_Phi(sched_first(block)));
161 be_add_reload(env, to_spill, sched_first(block));
165 /* We have to reload the value in pred-block */
166 predblock = get_Block_cfgpred_block(block, pos);
167 last = sched_last(predblock);
169 /* we might have projs and keepanys behind the jump... */
170 while(is_Proj(last) || be_is_Keep(last)) {
171 last = sched_prev(last);
172 assert(!sched_is_end(last));
174 assert(is_cfop(last));
176 // add the reload before the (cond-)jump
177 be_add_reload(env, to_spill, last);
180 void be_spill_phi(spill_env_t *env, ir_node *node) {
183 assert(is_Phi(node));
185 pset_insert_ptr(env->mem_phis, node);
187 // create spillinfos for the phi arguments
188 get_spillinfo(env, node);
189 for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
190 ir_node *arg = get_irn_n(node, i);
191 get_spillinfo(env, arg);
197 * / ___|_ __ ___ __ _| |_ ___ / ___| _ __ (_) | |___
198 * | | | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
199 * | |___| | | __/ (_| | || __/ ___) | |_) | | | \__ \
200 * \____|_| \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
205 * Schedules a node after an instruction. (That is the place after all projs and phis
206 * that are scheduled after the instruction)
207 * This function also skips phi nodes at the beginning of a block
209 static void sched_add_after_insn(ir_node *sched_after, ir_node *node) {
210 ir_node *next = sched_next(sched_after);
211 while(is_Proj(next) || is_Phi(next)) {
212 next = sched_next(next);
214 assert(next != NULL);
216 if(sched_is_end(next)) {
217 sched_add_after(sched_last(get_nodes_block(sched_after)), node);
219 sched_add_before(next, node);
226 * @param senv the spill environment
227 * @param irn the node that should be spilled
228 * @param ctx_irn an user of the spilled node
230 * @return a be_Spill node
232 static void spill_irn(spill_env_t *env, spill_info_t *spillinfo) {
233 ir_node *to_spill = spillinfo->spilled_node;
235 DBG((env->dbg, LEVEL_1, "%+F\n", to_spill));
237 /* Trying to spill an already spilled value, no need for a new spill
238 * node then, we can simply connect to the same one for this reload
240 * (although rematerialisation code should handle most of these cases
241 * this can still happen when spilling Phis)
243 if(be_is_Reload(to_spill)) {
244 spillinfo->spill = get_irn_n(to_spill, be_pos_Reload_mem);
248 spillinfo->spill = be_spill(env->arch_env, to_spill);
249 sched_add_after_insn(to_spill, spillinfo->spill);
252 static void spill_node(spill_env_t *env, spill_info_t *spillinfo);
255 * If the first usage of a Phi result would be out of memory
256 * there is no sense in allocating a register for it.
257 * Thus we spill it and all its operands to the same spill slot.
258 * Therefore the phi/dataB becomes a phi/Memory
260 * @param senv the spill environment
261 * @param phi the Phi node that should be spilled
262 * @param ctx_irn an user of the spilled node
264 static void spill_phi(spill_env_t *env, spill_info_t *spillinfo) {
265 ir_node *phi = spillinfo->spilled_node;
267 int arity = get_irn_arity(phi);
268 ir_node *block = get_nodes_block(phi);
273 /* build a new PhiM */
274 ins = alloca(sizeof(ir_node*) * arity);
275 for(i = 0; i < arity; ++i) {
276 ins[i] = get_irg_bad(env->chordal_env->irg);
278 spillinfo->spill = new_r_Phi(env->chordal_env->irg, block, arity, ins, mode_M);
280 for(i = 0; i < arity; ++i) {
281 ir_node *arg = get_irn_n(phi, i);
282 spill_info_t *arg_info = get_spillinfo(env, arg);
284 spill_node(env, arg_info);
286 set_irn_n(spillinfo->spill, i, arg_info->spill);
293 * @param senv the spill environment
294 * @param to_spill the node that should be spilled
296 static void spill_node(spill_env_t *env, spill_info_t *spillinfo) {
299 // the node should be tagged for spilling already...
300 if(spillinfo->spill != NULL)
303 to_spill = spillinfo->spilled_node;
304 if (is_Phi(to_spill) && pset_find_ptr(env->mem_phis, spillinfo->spilled_node)) {
305 spill_phi(env, spillinfo);
307 spill_irn(env, spillinfo);
314 * | _ \ ___ _ __ ___ __ _| |_ ___ _ __(_) __ _| (_)_______
315 * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_ / _ \
316 * | _ < __/ | | | | | (_| | || __/ | | | (_| | | |/ / __/
317 * |_| \_\___|_| |_| |_|\__,_|\__\___|_| |_|\__,_|_|_/___\___|
322 * Tests whether value @p arg is available before node @p reloader
323 * @returns 1 if value is available, 0 otherwise
325 static int is_value_available(spill_env_t *env, ir_node *arg, ir_node *reloader) {
326 if(is_Unknown(arg) || arg == new_NoMem())
332 if(arg == get_irg_frame(env->chordal_env->irg))
335 /* the following test does not work while spilling,
336 * because the liveness info is not adapted yet to the effects of the
337 * additional spills/reloads.
339 * So we can only do this test for ignore registers (of our register class)
341 if(arch_get_irn_reg_class(env->arch_env, arg, -1) == env->chordal_env->cls
342 && arch_irn_is(env->arch_env, arg, ignore)) {
345 /* we want to remat before the insn reloader
346 * thus an arguments is alive if
347 * - it interferes with the reloaders result
348 * - or it is (last-) used by reloader itself
350 if (values_interfere(env->chordal_env->lv, reloader, arg)) {
354 arity = get_irn_arity(reloader);
355 for (i = 0; i < arity; ++i) {
356 ir_node *rel_arg = get_irn_n(reloader, i);
366 * Checks whether the node can principally be rematerialized
368 static int is_remat_node(spill_env_t *env, ir_node *node) {
369 const arch_env_t *arch_env = env->arch_env;
371 assert(!be_is_Spill(node));
373 if(be_is_Reload(node))
376 // TODO why does arch_irn_is say rematerializable anyway?
377 if(be_is_Barrier(node))
380 if(arch_irn_is(arch_env, node, rematerializable))
383 if(be_is_StackParam(node))
390 * Check if a node is rematerializable. This tests for the following conditions:
392 * - The node itself is rematerializable
393 * - All arguments of the node are available or also rematerialisable
394 * - The costs for the rematerialisation operation is less or equal a limit
396 * Returns the costs needed for rematerialisation or something
397 * > REMAT_COST_LIMIT if remat is not possible.
399 static int check_remat_conditions_costs(spill_env_t *env, ir_node *spilled, ir_node *reloader, int parentcosts) {
404 if(!is_remat_node(env, spilled))
405 return REMAT_COST_LIMIT;
407 if(be_is_Reload(spilled)) {
410 costs += arch_get_op_estimated_cost(env->arch_env, spilled);
412 if(parentcosts + costs >= REMAT_COST_LIMIT)
413 return REMAT_COST_LIMIT;
416 for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
417 ir_node *arg = get_irn_n(spilled, i);
419 if(is_value_available(env, arg, reloader))
422 // we have to rematerialize the argument as well...
424 /* we only support rematerializing 1 argument at the moment,
425 * so that we don't have to care about register pressure
427 return REMAT_COST_LIMIT;
431 // TODO can we get more accurate costs than +1?
432 costs += check_remat_conditions_costs(env, arg, reloader, parentcosts + costs);
433 if(parentcosts + costs >= REMAT_COST_LIMIT)
434 return REMAT_COST_LIMIT;
440 static int check_remat_conditions(spill_env_t *env, ir_node *spilled, ir_node *reloader) {
441 int costs = check_remat_conditions_costs(env, spilled, reloader, 1);
443 return costs < REMAT_COST_LIMIT;
447 * Re-materialize a node.
449 * @param senv the spill environment
450 * @param spilled the node that was spilled
451 * @param reloader a irn that requires a reload
453 static ir_node *do_remat(spill_env_t *env, ir_node *spilled, ir_node *reloader) {
456 ir_node *bl = get_nodes_block(reloader);
459 ins = alloca(get_irn_arity(spilled) * sizeof(ins[0]));
460 for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
461 ir_node *arg = get_irn_n(spilled, i);
463 if(is_value_available(env, arg, reloader)) {
466 ins[i] = do_remat(env, arg, reloader);
470 /* create a copy of the node */
471 res = new_ir_node(get_irn_dbg_info(spilled), env->chordal_env->irg, bl,
473 get_irn_mode(spilled),
474 get_irn_arity(spilled),
476 copy_node_attr(spilled, res);
478 DBG((env->dbg, LEVEL_1, "Insert remat %+F before reloader %+F\n", res, reloader));
480 /* insert in schedule */
481 assert(!is_Block(reloader));
482 sched_add_before(reloader, res);
489 * |_ _|_ __ ___ ___ _ __| |_ | _ \ ___| | ___ __ _ __| |___
490 * | || '_ \/ __|/ _ \ '__| __| | |_) / _ \ |/ _ \ / _` |/ _` / __|
491 * | || | | \__ \ __/ | | |_ | _ < __/ | (_) | (_| | (_| \__ \
492 * |___|_| |_|___/\___|_| \__| |_| \_\___|_|\___/ \__,_|\__,_|___/
496 void be_insert_spills_reloads(spill_env_t *env) {
497 const arch_env_t *arch_env = env->arch_env;
500 /* process each spilled node */
501 DBG((env->dbg, LEVEL_1, "Insert spills and reloads:\n"));
502 for(si = set_first(env->spills); si; si = set_next(env->spills)) {
504 ir_mode *mode = get_irn_mode(si->spilled_node);
505 pset *values = pset_new_ptr(16);
507 /* go through all reloads for this spill */
508 for(rld = si->reloaders; rld; rld = rld->next) {
511 if (check_remat_conditions(env, si->spilled_node, rld->reloader)) {
512 new_val = do_remat(env, si->spilled_node, rld->reloader);
514 /* make sure we have a spill */
518 new_val = be_reload(arch_env, env->cls, rld->reloader, mode, si->spill);
521 DBG((env->dbg, LEVEL_1, " %+F of %+F before %+F\n", new_val, si->spilled_node, rld->reloader));
522 pset_insert_ptr(values, new_val);
525 if(pset_count(values) > 0) {
526 /* introduce copies, rewire the uses */
527 pset_insert_ptr(values, si->spilled_node);
528 be_ssa_constr_set_ignore(env->chordal_env->dom_front, env->chordal_env->lv, values, env->mem_phis);
534 // reloads are placed now, but we might reuse the spill environment for further spilling decisions
535 del_set(env->spills);
536 env->spills = new_set(cmp_spillinfo, 1024);