nsz Git - libfirm/blob - ir/be/bespill.c

   1 /*
   2  * Copyright (C) 1995-2007 University of Karlsruhe.  All right reserved.
   3  *
   4  * This file is part of libFirm.
   5  *
   6  * This file may be distributed and/or modified under the terms of the
   7  * GNU General Public License version 2 as published by the Free Software
   8  * Foundation and appearing in the file LICENSE.GPL included in the
   9  * packaging of this file.
  10  *
  11  * Licensees holding valid libFirm Professional Edition licenses may use
  12  * this file in accordance with the libFirm Commercial License.
  13  * Agreement provided with the Software.
  14  *
  15  * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
  16  * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  17  * PURPOSE.
  18  */
  19
  20 /**
  21  * @file
  22  * @brief       implementation of the spill/reload placement abstraction layer
  23  * @author      Daniel Grund, Sebastian Hack, Matthias Braun
  24  * @date                29.09.2005
  25  * @version     $Id$
  26  */
  27 #ifdef HAVE_CONFIG_H
  28 #include "config.h"
  29 #endif
  30
  31 #include <stdlib.h>
  32
  33 #include "pset.h"
  34 #include "irnode_t.h"
  35 #include "ircons_t.h"
  36 #include "iredges_t.h"
  37 #include "irbackedge_t.h"
  38 #include "irprintf.h"
  39 #include "ident_t.h"
  40 #include "type_t.h"
  41 #include "entity_t.h"
  42 #include "debug.h"
  43 #include "irgwalk.h"
  44 #include "array.h"
  45 #include "pdeq.h"
  46 #include "execfreq.h"
  47 #include "irnodeset.h"
  48 #include "error.h"
  49
  50 #include "bearch_t.h"
  51 #include "belive_t.h"
  52 #include "besched_t.h"
  53 #include "bespill.h"
  54 #include "belive_t.h"
  55 #include "benode_t.h"
  56 #include "bechordal_t.h"
  57 #include "bejavacoal.h"
  58 #include "benodesets.h"
  59 #include "bespilloptions.h"
  60 #include "bestatevent.h"
  61 #include "bessaconstr.h"
  62 #include "beirg_t.h"
  63 #include "beintlive_t.h"
  64 #include "bemodule.h"
  65
  66 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
  67
  68 #define REMAT_COST_INFINITE  1000
  69
  70 typedef struct reloader_t reloader_t;
  71 struct reloader_t {
  72         reloader_t *next;
  73         ir_node    *can_spill_after;
  74         ir_node    *reloader;
  75         ir_node    *rematted_node;
  76         int         remat_cost_delta; /** costs needed for rematerialization,
  77                                            compared to placing a reload */
  78 };
  79
  80 typedef struct spill_t spill_t;
  81 struct spill_t {
  82         spill_t *next;
  83         ir_node *before;   /**< spill has to be placed before this node (or earlier) */
  84         ir_node *spill;
  85 };
  86
  87 typedef struct spill_info_t spill_info_t;
  88 struct spill_info_t {
  89         ir_node    *to_spill;  /**< the value that should get spilled */
  90         reloader_t *reloaders; /**< list of places where the value should get
  91                                     reloaded */
  92         spill_t    *spills;    /**< list of latest places where spill must be
  93                                     placed */
  94         double      spill_costs; /**< costs needed for spilling the value */
  95         const arch_register_class_t *reload_cls; /** the register class in which the
  96                                                      reload should be placed */
  97 };
  98
  99 struct spill_env_t {
 100         const arch_env_t *arch_env;
 101         ir_graph         *irg;
 102         struct obstack    obst;
 103         be_irg_t         *birg;
 104         int               spill_cost;     /**< the cost of a single spill node */
 105         int               reload_cost;    /**< the cost of a reload node */
 106         set              *spills;         /**< all spill_info_t's, which must be
 107                                                placed */
 108         ir_nodeset_t      mem_phis;       /**< set of all spilled phis. */
 109         ir_exec_freq     *exec_freq;
 110         unsigned          new_nodes_idx;  /**< all old nodes idx is smaller than
 111                                                this */
 112
 113 #ifdef FIRM_STATISTICS
 114         unsigned          spill_count;
 115         unsigned          reload_count;
 116         unsigned          remat_count;
 117         unsigned          spilled_phi_count;
 118 #endif
 119 };
 120
 121 /**
 122  * Compare two spill infos.
 123  */
 124 static int cmp_spillinfo(const void *x, const void *y, size_t size)
 125 {
 126         const spill_info_t *xx = x;
 127         const spill_info_t *yy = y;
 128         (void) size;
 129
 130         return xx->to_spill != yy->to_spill;
 131 }
 132
 133 /**
 134  * Returns spill info for a specific value (the value that is to be spilled)
 135  */
 136 static spill_info_t *get_spillinfo(const spill_env_t *env, ir_node *value)
 137 {
 138         spill_info_t info, *res;
 139         int hash = nodeset_hash(value);
 140
 141         info.to_spill = value;
 142         res = set_find(env->spills, &info, sizeof(info), hash);
 143
 144         if (res == NULL) {
 145                 info.reloaders   = NULL;
 146                 info.spills      = NULL;
 147                 info.spill_costs = -1;
 148                 info.reload_cls  = NULL;
 149                 res = set_insert(env->spills, &info, sizeof(info), hash);
 150         }
 151
 152         return res;
 153 }
 154
 155 spill_env_t *be_new_spill_env(be_irg_t *birg)
 156 {
 157         const arch_env_t *arch_env = birg->main_env->arch_env;
 158
 159         spill_env_t *env        = xmalloc(sizeof(env[0]));
 160         env->spills                     = new_set(cmp_spillinfo, 1024);
 161         env->irg            = be_get_birg_irg(birg);
 162         env->birg           = birg;
 163         env->arch_env       = arch_env;
 164         ir_nodeset_init(&env->mem_phis);
 165         env->spill_cost     = arch_env->isa->spill_cost;
 166         env->reload_cost    = arch_env->isa->reload_cost;
 167         env->exec_freq      = be_get_birg_exec_freq(birg);
 168         obstack_init(&env->obst);
 169
 170 #ifdef FIRM_STATISTICS
 171         env->spill_count       = 0;
 172         env->reload_count      = 0;
 173         env->remat_count       = 0;
 174         env->spilled_phi_count = 0;
 175 #endif
 176
 177         return env;
 178 }
 179
 180 void be_delete_spill_env(spill_env_t *env)
 181 {
 182         del_set(env->spills);
 183         ir_nodeset_destroy(&env->mem_phis);
 184         obstack_free(&env->obst, NULL);
 185         free(env);
 186 }
 187
 188 /*
 189  *  ____  _                  ____      _                 _
 190  * |  _ \| | __ _  ___ ___  |  _ \ ___| | ___   __ _  __| |___
 191  * | |_) | |/ _` |/ __/ _ \ | |_) / _ \ |/ _ \ / _` |/ _` / __|
 192  * |  __/| | (_| | (_|  __/ |  _ <  __/ | (_) | (_| | (_| \__ \
 193  * |_|   |_|\__,_|\___\___| |_| \_\___|_|\___/ \__,_|\__,_|___/
 194  *
 195  */
 196
 197 void be_add_spill(spill_env_t *env, ir_node *to_spill, ir_node *before)
 198 {
 199 #if 1
 200         spill_info_t *spill_info = get_spillinfo(env, to_spill);
 201         spill_t      *spill;
 202         spill_t      *s;
 203         spill_t      *last;
 204
 205         DB((dbg, LEVEL_1, "Add spill of %+F before %+F\n", to_spill, before));
 206
 207         /* spills that are dominated by others are not needed */
 208         last = NULL;
 209         s    = spill_info->spills;
 210         for( ; s != NULL; s = s->next) {
 211                 /* no need to add this spill if it is dominated by another */
 212                 if(value_dominates(s->before, before)) {
 213                         DB((dbg, LEVEL_1, "...dominated by %+F, not added\n", s->before));
 214                         return;
 215                 }
 216                 /* remove spills that we dominate */
 217                 if(value_dominates(before, s->before)) {
 218                         DB((dbg, LEVEL_1, "...remove old spill at %+F\n", s->before));
 219                         if(last != NULL) {
 220                                 last->next         = s->next;
 221                         } else {
 222                                 spill_info->spills = s->next;
 223                         }
 224                 } else {
 225                         last = s;
 226                 }
 227         }
 228
 229         spill         = obstack_alloc(&env->obst, sizeof(spill[0]));
 230         spill->before = before;
 231         spill->next   = spill_info->spills;
 232         spill->spill  = NULL;
 233
 234         spill_info->spills = spill;
 235 #endif
 236 }
 237
 238 void be_add_remat(spill_env_t *env, ir_node *to_spill, ir_node *before,
 239                   ir_node *rematted_node)
 240 {
 241         spill_info_t *spill_info;
 242         reloader_t *reloader;
 243
 244         spill_info = get_spillinfo(env, to_spill);
 245
 246         /* add the remat information */
 247         reloader                   = obstack_alloc(&env->obst, sizeof(reloader[0]));
 248         reloader->next             = spill_info->reloaders;
 249         reloader->reloader         = before;
 250         reloader->rematted_node    = rematted_node;
 251         reloader->remat_cost_delta = 0; /* We will never have a cost win over a
 252                                            reload since we're not even allowed to
 253                                            create a reload */
 254
 255         spill_info->reloaders  = reloader;
 256
 257         DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be rematerialized before %+F\n",
 258                 to_spill, before));
 259 }
 260
 261 void be_add_reload2(spill_env_t *env, ir_node *to_spill, ir_node *before,
 262                 ir_node *can_spill_after, const arch_register_class_t *reload_cls,
 263                 int allow_remat)
 264 {
 265         spill_info_t *info;
 266         reloader_t *rel;
 267
 268         info = get_spillinfo(env, to_spill);
 269
 270         if (is_Phi(to_spill)) {
 271                 int i, arity;
 272
 273                 /* create spillinfos for the phi arguments */
 274                 for (i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
 275                         ir_node *arg = get_irn_n(to_spill, i);
 276                         get_spillinfo(env, arg);
 277                 }
 278         }
 279
 280         assert(!is_Proj(before) && !be_is_Keep(before));
 281
 282         /* put reload into list */
 283         rel                   = obstack_alloc(&env->obst, sizeof(rel[0]));
 284         rel->next             = info->reloaders;
 285         rel->reloader         = before;
 286         rel->rematted_node    = NULL;
 287         rel->can_spill_after  = can_spill_after;
 288         rel->remat_cost_delta = allow_remat ? 0 : REMAT_COST_INFINITE;
 289
 290         info->reloaders  = rel;
 291         assert(info->reload_cls == NULL || info->reload_cls == reload_cls);
 292         info->reload_cls = reload_cls;
 293
 294         DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be reloaded before %+F, may%s be rematerialized\n",
 295                 to_spill, before, allow_remat ? "" : " not"));
 296 }
 297
 298 void be_add_reload(spill_env_t *senv, ir_node *to_spill, ir_node *before,
 299                    const arch_register_class_t *reload_cls, int allow_remat)
 300 {
 301         be_add_reload2(senv, to_spill, before, to_spill, reload_cls, allow_remat);
 302
 303 }
 304
 305 ir_node *be_get_end_of_block_insertion_point(const ir_node *block)
 306 {
 307         ir_node *last = sched_last(block);
 308
 309         /* we might have keeps behind the jump... */
 310         while(be_is_Keep(last)) {
 311                 last = sched_prev(last);
 312                 assert(!sched_is_end(last));
 313         }
 314
 315         assert(is_cfop(last));
 316
 317         /* add the reload before the (cond-)jump */
 318         return last;
 319 }
 320
 321 static ir_node *skip_keeps_phis(ir_node *node)
 322 {
 323         node = sched_next(node);
 324         while(is_Phi(node) || be_is_Keep(node)) {
 325                 node = sched_next(node);
 326         }
 327         return node;
 328 }
 329
 330 /**
 331  * Returns the point at which you can insert a node that should be executed
 332  * before block @p block when coming from pred @p pos.
 333  */
 334 static ir_node *get_block_insertion_point(ir_node *block, int pos)
 335 {
 336         ir_node *predblock;
 337
 338         /* simply add the reload to the beginning of the block if we only have 1
 339          * predecessor. We don't need to check for phis as there can't be any in a
 340          * block with only 1 pred. */
 341         if(get_Block_n_cfgpreds(block) == 1) {
 342                 assert(!is_Phi(sched_first(block)));
 343                 return sched_first(block);
 344         }
 345
 346         /* We have to reload the value in pred-block */
 347         predblock = get_Block_cfgpred_block(block, pos);
 348         return be_get_end_of_block_insertion_point(predblock);
 349 }
 350
 351 void be_add_reload_at_end(spill_env_t *env, ir_node *to_spill,
 352                           const ir_node *block,
 353                           const arch_register_class_t *reload_cls,
 354                           int allow_remat)
 355 {
 356         ir_node *before = be_get_end_of_block_insertion_point(block);
 357         be_add_reload(env, to_spill, before, reload_cls, allow_remat);
 358 }
 359
 360 void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block,
 361                            int pos,     const arch_register_class_t *reload_cls,
 362                            int allow_remat)
 363 {
 364         ir_node *before = get_block_insertion_point(block, pos);
 365         be_add_reload(env, to_spill, before, reload_cls, allow_remat);
 366 }
 367
 368 void be_spill_phi(spill_env_t *env, ir_node *node)
 369 {
 370         ir_node *block;
 371         spill_info_t* spill;
 372         int i, arity;
 373
 374         assert(is_Phi(node));
 375
 376         ir_nodeset_insert(&env->mem_phis, node);
 377
 378         /* create spills for the phi arguments */
 379         block = get_nodes_block(node);
 380         spill = get_spillinfo(env, node);
 381         for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
 382                 ir_node *arg        = get_irn_n(node, i);
 383                 ir_node *insert;
 384                 //get_spillinfo(env, arg);
 385
 386                 /* some backends have virtual noreg/unknown nodes that are not scheduled
 387                  * and simply always available. */
 388                 if(!sched_is_scheduled(arg)) {
 389                         ir_node *pred_block = get_Block_cfgpred_block(block, i);
 390                         insert = be_get_end_of_block_insertion_point(pred_block);
 391                 } else {
 392                         insert = skip_keeps_phis(arg);
 393                 }
 394
 395                 be_add_spill(env, arg, insert);
 396         }
 397 }
 398
 399 /*
 400  *   ____                _         ____        _ _ _
 401  *  / ___|_ __ ___  __ _| |_ ___  / ___| _ __ (_) | |___
 402  * | |   | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
 403  * | |___| | |  __/ (_| | ||  __/  ___) | |_) | | | \__ \
 404  *  \____|_|  \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
 405  *                                      |_|
 406  */
 407
 408 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo);
 409
 410 /**
 411  * Creates a spill.
 412  *
 413  * @param senv      the spill environment
 414  * @param irn       the node that should be spilled
 415  * @param ctx_irn   an user of the spilled node
 416  *
 417  * @return a be_Spill node
 418  */
 419 static void spill_irn(spill_env_t *env, spill_info_t *spillinfo)
 420 {
 421         ir_node *to_spill = spillinfo->to_spill;
 422         spill_t *spill;
 423
 424         /* determine_spill_costs must have been run before */
 425         assert(spillinfo->spill_costs >= 0);
 426
 427         /* some backends have virtual noreg/unknown nodes that are not scheduled
 428          * and simply always available. */
 429         if(!sched_is_scheduled(to_spill)) {
 430                 /* override spillinfos or create a new one */
 431                 spillinfo->spills->spill = new_NoMem();
 432                 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
 433                 return;
 434         }
 435
 436         DBG((dbg, LEVEL_1, "spilling %+F ... ", to_spill));
 437         spill = spillinfo->spills;
 438         for( ; spill != NULL; spill = spill->next) {
 439                 ir_node *block  = get_block(spill->before);
 440                 ir_node *before = spill->before;
 441
 442                 /* place all spills before the reloads (as we can't guarantee the
 443                  * same order as the be_add_spill and be_add_reload calls */
 444                 while(get_irn_idx(sched_prev(before)) > env->new_nodes_idx) {
 445                         before = sched_prev(before);
 446                 }
 447
 448                 spill->spill    = be_spill(env->arch_env, block, to_spill);
 449                 sched_add_before(before, spill->spill);
 450                 DB((dbg, LEVEL_1, "\t%+F before %+F\n", spill->spill, before));
 451 #ifdef FIRM_STATISTICS
 452                 env->spill_count++;
 453 #endif
 454         }
 455         DBG((dbg, LEVEL_1, "\n"));
 456 }
 457
 458 static void spill_node(spill_env_t *env, spill_info_t *spillinfo);
 459
 460 /**
 461  * If the first usage of a Phi result would be out of memory
 462  * there is no sense in allocating a register for it.
 463  * Thus we spill it and all its operands to the same spill slot.
 464  * Therefore the phi/dataB becomes a phi/Memory
 465  *
 466  * @param senv      the spill environment
 467  * @param phi       the Phi node that should be spilled
 468  * @param ctx_irn   an user of the spilled node
 469  */
 470 static void spill_phi(spill_env_t *env, spill_info_t *spillinfo)
 471 {
 472         ir_graph *irg   = env->irg;
 473         ir_node  *phi   = spillinfo->to_spill;
 474         ir_node  *block = get_nodes_block(phi);
 475         ir_node  *unknown;
 476         ir_node **ins;
 477         spill_t  *spill;
 478         int       i;
 479         int       arity;
 480
 481         assert(is_Phi(phi));
 482         assert(!get_opt_cse());
 483         DBG((dbg, LEVEL_1, "spilling Phi %+F:\n", phi));
 484
 485         /* build a new PhiM */
 486         arity   = get_irn_arity(phi);
 487         ins     = alloca(sizeof(ir_node*) * arity);
 488         unknown = new_r_Unknown(irg, mode_M);
 489         for(i = 0; i < arity; ++i) {
 490                 ins[i] = unknown;
 491         }
 492
 493         /* override or replace spills list... */
 494         spill         = obstack_alloc(&env->obst, sizeof(spill[0]));
 495         spill->before = skip_keeps_phis(phi);
 496         spill->spill  = new_r_Phi(irg, block, arity, ins, mode_M);
 497         spill->next   = NULL;
 498
 499         spillinfo->spills = spill;
 500 #ifdef FIRM_STATISTICS
 501         env->spilled_phi_count++;
 502 #endif
 503
 504         for(i = 0; i < arity; ++i) {
 505                 ir_node      *arg      = get_irn_n(phi, i);
 506                 spill_info_t *arg_info = get_spillinfo(env, arg);
 507
 508                 determine_spill_costs(env, arg_info);
 509                 spill_node(env, arg_info);
 510
 511                 set_irn_n(spill->spill, i, arg_info->spills->spill);
 512         }
 513         DBG((dbg, LEVEL_1, "... done spilling Phi %+F, created PhiM %+F\n", phi,
 514              spill->spill));
 515 }
 516
 517 /**
 518  * Spill a node.
 519  *
 520  * @param senv      the spill environment
 521  * @param to_spill  the node that should be spilled
 522  */
 523 static void spill_node(spill_env_t *env, spill_info_t *spillinfo)
 524 {
 525         ir_node *to_spill;
 526
 527         /* node is already spilled */
 528         if(spillinfo->spills != NULL && spillinfo->spills->spill != NULL)
 529                 return;
 530
 531         to_spill = spillinfo->to_spill;
 532
 533         if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
 534                 spill_phi(env, spillinfo);
 535         } else {
 536                 spill_irn(env, spillinfo);
 537         }
 538 }
 539
 540 /*
 541  *
 542  *  ____                      _            _       _ _
 543  * |  _ \ ___ _ __ ___   __ _| |_ ___ _ __(_) __ _| (_)_______
 544  * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_  / _ \
 545  * |  _ <  __/ | | | | | (_| | ||  __/ |  | | (_| | | |/ /  __/
 546  * |_| \_\___|_| |_| |_|\__,_|\__\___|_|  |_|\__,_|_|_/___\___|
 547  *
 548  */
 549
 550 /**
 551  * Tests whether value @p arg is available before node @p reloader
 552  * @returns 1 if value is available, 0 otherwise
 553  */
 554 static int is_value_available(spill_env_t *env, const ir_node *arg,
 555                               const ir_node *reloader)
 556 {
 557         if(is_Unknown(arg) || arg == new_NoMem())
 558                 return 1;
 559
 560         if(be_is_Spill(arg))
 561                 return 1;
 562
 563         if(arg == get_irg_frame(env->irg))
 564                 return 1;
 565
 566         /* hack for now (happens when command should be inserted at end of block) */
 567         if(is_Block(reloader)) {
 568                 return 0;
 569         }
 570
 571         /*
 572          * Ignore registers are always available
 573          */
 574         if(arch_irn_is(env->arch_env, arg, ignore)) {
 575                 return 1;
 576         }
 577
 578         /* the following test does not work while spilling,
 579          * because the liveness info is not adapted yet to the effects of the
 580          * additional spills/reloads.
 581          */
 582 #if 0
 583         /* we want to remat before the insn reloader
 584          * thus an arguments is alive if
 585          *   - it interferes with the reloaders result
 586          *   - or it is (last-) used by reloader itself
 587          */
 588         if (values_interfere(env->birg->lv, reloader, arg)) {
 589                 return 1;
 590         }
 591
 592         arity = get_irn_arity(reloader);
 593         for (i = 0; i < arity; ++i) {
 594                 ir_node *rel_arg = get_irn_n(reloader, i);
 595                 if (rel_arg == arg)
 596                         return 1;
 597         }
 598 #endif
 599
 600         return 0;
 601 }
 602
 603 /**
 604  * Checks whether the node can principally be rematerialized
 605  */
 606 static int is_remat_node(spill_env_t *env, const ir_node *node)
 607 {
 608         const arch_env_t *arch_env = env->arch_env;
 609
 610         assert(!be_is_Spill(node));
 611
 612         if(arch_irn_is(arch_env, node, rematerializable))
 613                 return 1;
 614
 615         return 0;
 616 }
 617
 618 /**
 619  * Check if a node is rematerializable. This tests for the following conditions:
 620  *
 621  * - The node itself is rematerializable
 622  * - All arguments of the node are available or also rematerialisable
 623  * - The costs for the rematerialisation operation is less or equal a limit
 624  *
 625  * Returns the costs needed for rematerialisation or something
 626  * >= REMAT_COST_INFINITE if remat is not possible.
 627  */
 628 static int check_remat_conditions_costs(spill_env_t *env,
 629                 const ir_node *spilled, const ir_node *reloader, int parentcosts)
 630 {
 631         int i, arity;
 632         int argremats;
 633         int costs = 0;
 634
 635         if(!is_remat_node(env, spilled))
 636                 return REMAT_COST_INFINITE;
 637
 638         if(be_is_Reload(spilled)) {
 639                 costs += 2;
 640         } else {
 641                 costs += arch_get_op_estimated_cost(env->arch_env, spilled);
 642         }
 643         if(parentcosts + costs >= env->reload_cost + env->spill_cost) {
 644                 return REMAT_COST_INFINITE;
 645         }
 646         if(arch_irn_is(env->arch_env, spilled, modify_flags)) {
 647                 return REMAT_COST_INFINITE;
 648         }
 649
 650         argremats = 0;
 651         for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
 652                 ir_node *arg = get_irn_n(spilled, i);
 653
 654                 if(is_value_available(env, arg, reloader))
 655                         continue;
 656
 657                 /* we have to rematerialize the argument as well */
 658                 if(argremats >= 1) {
 659                         /* we only support rematerializing 1 argument at the moment,
 660                          * so that we don't have to care about register pressure
 661                          */
 662                         return REMAT_COST_INFINITE;
 663                 }
 664                 argremats++;
 665
 666                 costs += check_remat_conditions_costs(env, arg, reloader,
 667                                                       parentcosts + costs);
 668                 if(parentcosts + costs >= env->reload_cost + env->spill_cost)
 669                         return REMAT_COST_INFINITE;
 670         }
 671
 672         return costs;
 673 }
 674
 675 /**
 676  * Re-materialize a node.
 677  *
 678  * @param senv      the spill environment
 679  * @param spilled   the node that was spilled
 680  * @param reloader  a irn that requires a reload
 681  */
 682 static ir_node *do_remat(spill_env_t *env, ir_node *spilled, ir_node *reloader)
 683 {
 684         int i, arity;
 685         ir_node *res;
 686         ir_node *bl;
 687         ir_node **ins;
 688
 689         if(is_Block(reloader)) {
 690                 bl = reloader;
 691         } else {
 692                 bl = get_nodes_block(reloader);
 693         }
 694
 695         ins = alloca(get_irn_arity(spilled) * sizeof(ins[0]));
 696         for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
 697                 ir_node *arg = get_irn_n(spilled, i);
 698
 699                 if(is_value_available(env, arg, reloader)) {
 700                         ins[i] = arg;
 701                 } else {
 702                         ins[i] = do_remat(env, arg, reloader);
 703 #ifdef FIRM_STATISTICS
 704                         /* don't count the recursive call as remat */
 705                         env->remat_count--;
 706 #endif
 707                 }
 708         }
 709
 710         /* create a copy of the node */
 711         res = new_ir_node(get_irn_dbg_info(spilled), env->irg, bl,
 712                           get_irn_op(spilled), get_irn_mode(spilled),
 713                           get_irn_arity(spilled), ins);
 714         copy_node_attr(spilled, res);
 715         new_backedge_info(res);
 716
 717         DBG((dbg, LEVEL_1, "Insert remat %+F of %+F before reloader %+F\n", res, spilled, reloader));
 718
 719         if (! is_Proj(res)) {
 720                 /* insert in schedule */
 721                 sched_reset(res);
 722                 sched_add_before(reloader, res);
 723 #ifdef FIRM_STATISTICS
 724                 env->remat_count++;
 725 #endif
 726         }
 727
 728         return res;
 729 }
 730
 731 double be_get_spill_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
 732 {
 733         ir_node *block = get_nodes_block(before);
 734         double   freq  = get_block_execfreq(env->exec_freq, block);
 735         (void) to_spill;
 736
 737         return env->spill_cost * freq;
 738 }
 739
 740 double be_get_reload_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
 741 {
 742         ir_node      *block = get_nodes_block(before);
 743         double        freq  = get_block_execfreq(env->exec_freq, block);
 744
 745         if(be_do_remats) {
 746                 /* is the node rematerializable? */
 747                 int costs = check_remat_conditions_costs(env, to_spill, before, 0);
 748                 if(costs < env->reload_cost)
 749                         return costs * freq;
 750         }
 751
 752         return env->reload_cost * freq;
 753 }
 754
 755 int be_is_rematerializable(spill_env_t *env, const ir_node *to_remat,
 756                            const ir_node *before)
 757 {
 758         return check_remat_conditions_costs(env, to_remat, before, 0) < REMAT_COST_INFINITE;
 759 }
 760
 761 double be_get_reload_costs_on_edge(spill_env_t *env, ir_node *to_spill,
 762                                    ir_node *block, int pos)
 763 {
 764         ir_node *before = get_block_insertion_point(block, pos);
 765         return be_get_reload_costs(env, to_spill, before);
 766 }
 767
 768 /*
 769  *  ___                     _     ____      _                 _
 770  * |_ _|_ __  ___  ___ _ __| |_  |  _ \ ___| | ___   __ _  __| |___
 771  *  | || '_ \/ __|/ _ \ '__| __| | |_) / _ \ |/ _ \ / _` |/ _` / __|
 772  *  | || | | \__ \  __/ |  | |_  |  _ <  __/ | (_) | (_| | (_| \__ \
 773  * |___|_| |_|___/\___|_|   \__| |_| \_\___|_|\___/ \__,_|\__,_|___/
 774  *
 775  */
 776
 777 /**
 778  * analyzes how to best spill a node and determine costs for that
 779  */
 780 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo)
 781 {
 782         ir_node *to_spill = spillinfo->to_spill;
 783         ir_node *spill_block;
 784         spill_t *spill;
 785         double   spill_execfreq;
 786
 787         /* already calculated? */
 788         if(spillinfo->spill_costs >= 0)
 789                 return;
 790
 791         assert(! arch_irn_is(env->arch_env, to_spill, dont_spill));
 792         assert(!be_is_Reload(to_spill));
 793
 794         /* some backends have virtual noreg/unknown nodes that are not scheduled
 795          * and simply always available.
 796          * TODO: this is kinda hairy, the NoMem is correct for an Unknown as Phi
 797          * predecessor (of a PhiM) but this test might match other things too...
 798          */
 799         if(!sched_is_scheduled(to_spill)) {
 800                 /* override spillinfos or create a new one */
 801                 spill_t *spill = obstack_alloc(&env->obst, sizeof(spill[0]));
 802                 spill->before  = NULL;
 803                 spill->next    = NULL;
 804                 spill->spill   = new_NoMem();
 805
 806                 spillinfo->spills      = spill;
 807                 spillinfo->spill_costs = 0;
 808
 809                 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
 810                 return;
 811         }
 812
 813         spill_block    = get_nodes_block(to_spill);
 814         spill_execfreq = get_block_execfreq(env->exec_freq, spill_block);
 815
 816         if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
 817                 /* TODO calculate correct costs...
 818                  * (though we can't remat this node anyway so no big problem) */
 819                 spillinfo->spill_costs = env->spill_cost * spill_execfreq;
 820                 return;
 821         }
 822
 823         if(spillinfo->spills != NULL) {
 824                 spill_t *s;
 825                 double   spills_execfreq;
 826
 827                 /* calculate sum of executaion frequencies of individual spills */
 828                 spills_execfreq = 0;
 829                 s               = spillinfo->spills;
 830                 for( ; s != NULL; s = s->next) {
 831                         ir_node *spill_block = s->before;
 832                         double   freq;
 833
 834                         if(!is_Block(spill_block)) {
 835                                 spill_block = get_nodes_block(spill_block);
 836                         }
 837                         freq = get_block_execfreq(env->exec_freq, spill_block);
 838
 839                         spills_execfreq += freq;
 840                 }
 841
 842                 DB((dbg, LEVEL_1, "%+F: latespillcosts %f after def: %f\n", to_spill,
 843                     spills_execfreq * env->spill_cost,
 844                     spill_execfreq * env->spill_cost));
 845
 846                 /* multi-/latespill is advantageous -> return*/
 847                 if(spills_execfreq < spill_execfreq) {
 848                         DB((dbg, LEVEL_1, "use latespills for %+F\n", to_spill));
 849                         spillinfo->spill_costs = spills_execfreq * env->spill_cost;
 850                         return;
 851                 }
 852         }
 853
 854         /* override spillinfos or create a new one */
 855         spill         = obstack_alloc(&env->obst, sizeof(spill[0]));
 856         spill->before = skip_keeps_phis(to_spill);
 857         spill->next   = NULL;
 858         spill->spill  = NULL;
 859
 860         spillinfo->spills      = spill;
 861         spillinfo->spill_costs = spill_execfreq * env->spill_cost;
 862         DB((dbg, LEVEL_1, "spill %+F after definition\n", to_spill));
 863 }
 864
 865 void be_insert_spills_reloads(spill_env_t *env)
 866 {
 867         ir_graph              *irg       = env->irg;
 868         const arch_env_t      *arch_env  = env->arch_env;
 869         const ir_exec_freq    *exec_freq = env->exec_freq;
 870         spill_info_t          *si;
 871         ir_nodeset_iterator_t  iter;
 872         ir_node               *node;
 873
 874         env->new_nodes_idx = get_irg_last_idx(irg);
 875
 876         /* create all phi-ms first, this is needed so, that phis, hanging on
 877            spilled phis work correctly */
 878         foreach_ir_nodeset(&env->mem_phis, node, iter) {
 879                 spill_info_t *info = get_spillinfo(env, node);
 880                 spill_node(env, info);
 881         }
 882
 883         /* process each spilled node */
 884         for (si = set_first(env->spills); si; si = set_next(env->spills)) {
 885                 reloader_t *rld;
 886                 ir_node  *to_spill        = si->to_spill;
 887                 ir_mode  *mode            = get_irn_mode(to_spill);
 888                 ir_node **copies          = NEW_ARR_F(ir_node*, 0);
 889                 double    all_remat_costs = 0; /** costs when we would remat all nodes */
 890                 int       force_remat     = 0;
 891
 892                 DBG((dbg, LEVEL_1, "\nhandling all reloaders of %+F:\n", to_spill));
 893
 894                 determine_spill_costs(env, si);
 895
 896                 /* determine possibility of rematerialisations */
 897                 if(be_do_remats) {
 898                         /* calculate cost savings for each indivial value when it would
 899                            be rematted instead of reloaded */
 900                         for (rld = si->reloaders; rld != NULL; rld = rld->next) {
 901                                 double   freq;
 902                                 int      remat_cost;
 903                                 int      remat_cost_delta;
 904                                 ir_node *block;
 905                                 ir_node *reloader = rld->reloader;
 906
 907                                 if(rld->rematted_node != NULL) {
 908                                         DBG((dbg, LEVEL_2, "\tforced remat %+F before %+F\n",
 909                                              rld->rematted_node, reloader));
 910                                         continue;
 911                                 }
 912                                 if(rld->remat_cost_delta >= REMAT_COST_INFINITE) {
 913                                         DBG((dbg, LEVEL_2, "\treload before %+F is forbidden\n",
 914                                              reloader));
 915                                         all_remat_costs = REMAT_COST_INFINITE;
 916                                         continue;
 917                                 }
 918
 919                                 remat_cost  = check_remat_conditions_costs(env, to_spill,
 920                                                                            reloader, 0);
 921                                 if(remat_cost >= REMAT_COST_INFINITE) {
 922                                         DBG((dbg, LEVEL_2, "\tremat before %+F not possible\n",
 923                                              reloader));
 924                                         rld->remat_cost_delta = REMAT_COST_INFINITE;
 925                                         all_remat_costs       = REMAT_COST_INFINITE;
 926                                         continue;
 927                                 }
 928
 929                                 remat_cost_delta      = remat_cost - env->reload_cost;
 930                                 rld->remat_cost_delta = remat_cost_delta;
 931                                 block                 = is_Block(reloader) ? reloader : get_nodes_block(reloader);
 932                                 freq                  = get_block_execfreq(exec_freq, block);
 933                                 all_remat_costs      += remat_cost_delta * freq;
 934                                 DBG((dbg, LEVEL_2, "\tremat costs delta before %+F: "
 935                                      "%d (rel %f)\n", reloader, remat_cost_delta,
 936                                      remat_cost_delta * freq));
 937                         }
 938                         if(all_remat_costs < REMAT_COST_INFINITE) {
 939                                 /* we don't need the costs for the spill if we can remat
 940                                    all reloaders */
 941                                 all_remat_costs -= si->spill_costs;
 942
 943                                 DBG((dbg, LEVEL_2, "\tspill costs %d (rel %f)\n",
 944                                      env->spill_cost, si->spill_costs));
 945                         }
 946
 947                         if(all_remat_costs < 0) {
 948                                 DBG((dbg, LEVEL_1, "\nforcing remats of all reloaders (%f)\n",
 949                                      all_remat_costs));
 950                                 force_remat = 1;
 951                         }
 952                 }
 953
 954                 /* go through all reloads for this spill */
 955                 for (rld = si->reloaders; rld != NULL; rld = rld->next) {
 956                         ir_node *copy; /* a reload is a "copy" of the original value */
 957
 958                         if (rld->rematted_node != NULL) {
 959                                 copy = rld->rematted_node;
 960                                 sched_add_before(rld->reloader, copy);
 961                         } else if (be_do_remats &&
 962                                         (force_remat || rld->remat_cost_delta < 0)) {
 963                                 copy = do_remat(env, to_spill, rld->reloader);
 964                         } else {
 965                                 /* make sure we have a spill */
 966                                 spill_node(env, si);
 967
 968                                 /* create a reload, use the first spill for now SSA
 969                                  * reconstruction for memory comes below */
 970                                 assert(si->spills != NULL);
 971                                 copy = be_reload(arch_env, si->reload_cls, rld->reloader, mode,
 972                                                  si->spills->spill);
 973 #ifdef FIRM_STATISTICS
 974                                 env->reload_count++;
 975 #endif
 976                         }
 977
 978                         DBG((dbg, LEVEL_1, " %+F of %+F before %+F\n",
 979                              copy, to_spill, rld->reloader));
 980                         ARR_APP1(ir_node*, copies, copy);
 981                 }
 982
 983                 /* if we had any reloads or remats, then we need to reconstruct the
 984                  * SSA form for the spilled value */
 985                 if (ARR_LEN(copies) > 0) {
 986                         be_ssa_construction_env_t senv;
 987                         /* be_lv_t *lv = be_get_birg_liveness(env->birg); */
 988
 989                         be_ssa_construction_init(&senv, env->birg);
 990                         be_ssa_construction_add_copy(&senv, to_spill);
 991                         be_ssa_construction_add_copies(&senv, copies, ARR_LEN(copies));
 992                         be_ssa_construction_fix_users(&senv, to_spill);
 993
 994 #if 0
 995                         /* no need to enable this as long as we invalidate liveness
 996                            after this function... */
 997                         be_ssa_construction_update_liveness_phis(&senv);
 998                         be_liveness_update(to_spill);
 999                         len = ARR_LEN(copies);
1000                         for(i = 0; i < len; ++i) {
1001                                 be_liveness_update(lv, copies[i]);
1002                         }
1003 #endif
1004                         be_ssa_construction_destroy(&senv);
1005                 }
1006                 /* need to reconstruct SSA form if we had multiple spills */
1007                 if (si->spills != NULL && si->spills->next != NULL) {
1008                         spill_t *spill;
1009                         int      spill_count = 0;
1010
1011                         be_ssa_construction_env_t senv;
1012
1013                         be_ssa_construction_init(&senv, env->birg);
1014                         spill = si->spills;
1015                         for( ; spill != NULL; spill = spill->next) {
1016                                 /* maybe we rematerialized the value and need no spill */
1017                                 if(spill->spill == NULL)
1018                                         continue;
1019                                 be_ssa_construction_add_copy(&senv, spill->spill);
1020                                 spill_count++;
1021                         }
1022                         if(spill_count > 1) {
1023                                 /* all reloads are attached to the first spill, fix them now */
1024                                 be_ssa_construction_fix_users(&senv, si->spills->spill);
1025                         }
1026
1027                         be_ssa_construction_destroy(&senv);
1028                 }
1029
1030                 DEL_ARR_F(copies);
1031                 si->reloaders = NULL;
1032         }
1033
1034         stat_ev_dbl("spill_spills", env->spill_count);
1035         stat_ev_dbl("spill_reloads", env->reload_count);
1036         stat_ev_dbl("spill_remats", env->remat_count);
1037         stat_ev_dbl("spill_spilled_phis", env->spilled_phi_count);
1038
1039         /* Matze: In theory be_ssa_construction should take care of the liveness...
1040          * try to disable this again in the future */
1041         be_liveness_invalidate(env->birg->lv);
1042
1043         be_remove_dead_nodes_from_schedule(env->birg);
1044 }
1045
1046 void be_init_spill(void)
1047 {
1048         FIRM_DBG_REGISTER(dbg, "firm.be.spill");
1049 }
1050
1051 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spill);