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

   1 /*
   2  * Copyright (C) 1995-2008 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 "bespilloptions.h"
  59 #include "bestatevent.h"
  60 #include "bessaconstr.h"
  61 #include "beirg_t.h"
  62 #include "beintlive_t.h"
  63 #include "bemodule.h"
  64 #include "be_t.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 = hash_irn(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         assert(! arch_irn_is(env->arch_env, to_spill, dont_spill));
 206         DB((dbg, LEVEL_1, "Add spill of %+F before %+F\n", to_spill, before));
 207
 208         /* spills that are dominated by others are not needed */
 209         last = NULL;
 210         s    = spill_info->spills;
 211         for( ; s != NULL; s = s->next) {
 212                 /* no need to add this spill if it is dominated by another */
 213                 if(value_dominates(s->before, before)) {
 214                         DB((dbg, LEVEL_1, "...dominated by %+F, not added\n", s->before));
 215                         return;
 216                 }
 217                 /* remove spills that we dominate */
 218                 if(value_dominates(before, s->before)) {
 219                         DB((dbg, LEVEL_1, "...remove old spill at %+F\n", s->before));
 220                         if(last != NULL) {
 221                                 last->next         = s->next;
 222                         } else {
 223                                 spill_info->spills = s->next;
 224                         }
 225                 } else {
 226                         last = s;
 227                 }
 228         }
 229
 230         spill         = obstack_alloc(&env->obst, sizeof(spill[0]));
 231         spill->before = before;
 232         spill->next   = spill_info->spills;
 233         spill->spill  = NULL;
 234
 235         spill_info->spills = spill;
 236 #endif
 237 }
 238
 239 void be_add_remat(spill_env_t *env, ir_node *to_spill, ir_node *before,
 240                   ir_node *rematted_node)
 241 {
 242         spill_info_t *spill_info;
 243         reloader_t *reloader;
 244
 245         spill_info = get_spillinfo(env, to_spill);
 246
 247         /* add the remat information */
 248         reloader                   = obstack_alloc(&env->obst, sizeof(reloader[0]));
 249         reloader->next             = spill_info->reloaders;
 250         reloader->reloader         = before;
 251         reloader->rematted_node    = rematted_node;
 252         reloader->remat_cost_delta = 0; /* We will never have a cost win over a
 253                                            reload since we're not even allowed to
 254                                            create a reload */
 255
 256         spill_info->reloaders  = reloader;
 257
 258         DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be rematerialized before %+F\n",
 259                 to_spill, before));
 260 }
 261
 262 void be_add_reload2(spill_env_t *env, ir_node *to_spill, ir_node *before,
 263                 ir_node *can_spill_after, const arch_register_class_t *reload_cls,
 264                 int allow_remat)
 265 {
 266         spill_info_t *info;
 267         reloader_t *rel;
 268
 269         assert(! arch_irn_is(env->arch_env, to_spill, dont_spill));
 270
 271         info = get_spillinfo(env, to_spill);
 272
 273         if (is_Phi(to_spill)) {
 274                 int i, arity;
 275
 276                 /* create spillinfos for the phi arguments */
 277                 for (i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
 278                         ir_node *arg = get_irn_n(to_spill, i);
 279                         get_spillinfo(env, arg);
 280                 }
 281         }
 282
 283         assert(!is_Proj(before) && !be_is_Keep(before));
 284
 285         /* put reload into list */
 286         rel                   = obstack_alloc(&env->obst, sizeof(rel[0]));
 287         rel->next             = info->reloaders;
 288         rel->reloader         = before;
 289         rel->rematted_node    = NULL;
 290         rel->can_spill_after  = can_spill_after;
 291         rel->remat_cost_delta = allow_remat ? 0 : REMAT_COST_INFINITE;
 292
 293         info->reloaders  = rel;
 294         assert(info->reload_cls == NULL || info->reload_cls == reload_cls);
 295         info->reload_cls = reload_cls;
 296
 297         DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be reloaded before %+F, may%s be rematerialized\n",
 298                 to_spill, before, allow_remat ? "" : " not"));
 299 }
 300
 301 void be_add_reload(spill_env_t *senv, ir_node *to_spill, ir_node *before,
 302                    const arch_register_class_t *reload_cls, int allow_remat)
 303 {
 304         be_add_reload2(senv, to_spill, before, to_spill, reload_cls, allow_remat);
 305
 306 }
 307
 308 ir_node *be_get_end_of_block_insertion_point(const ir_node *block)
 309 {
 310         ir_node *last = sched_last(block);
 311
 312         /* we might have keeps behind the jump... */
 313         while(be_is_Keep(last)) {
 314                 last = sched_prev(last);
 315                 assert(!sched_is_end(last));
 316         }
 317
 318         assert(is_cfop(last));
 319
 320         /* add the reload before the (cond-)jump */
 321         return last;
 322 }
 323
 324 static ir_node *skip_keeps_phis(ir_node *node)
 325 {
 326         node = sched_next(node);
 327         while(is_Phi(node) || be_is_Keep(node)) {
 328                 node = sched_next(node);
 329         }
 330         return node;
 331 }
 332
 333 /**
 334  * Returns the point at which you can insert a node that should be executed
 335  * before block @p block when coming from pred @p pos.
 336  */
 337 static ir_node *get_block_insertion_point(ir_node *block, int pos)
 338 {
 339         ir_node *predblock;
 340
 341         /* simply add the reload to the beginning of the block if we only have 1
 342          * predecessor. We don't need to check for phis as there can't be any in a
 343          * block with only 1 pred. */
 344         if(get_Block_n_cfgpreds(block) == 1) {
 345                 assert(!is_Phi(sched_first(block)));
 346                 return sched_first(block);
 347         }
 348
 349         /* We have to reload the value in pred-block */
 350         predblock = get_Block_cfgpred_block(block, pos);
 351         return be_get_end_of_block_insertion_point(predblock);
 352 }
 353
 354 void be_add_reload_at_end(spill_env_t *env, ir_node *to_spill,
 355                           const ir_node *block,
 356                           const arch_register_class_t *reload_cls,
 357                           int allow_remat)
 358 {
 359         ir_node *before = be_get_end_of_block_insertion_point(block);
 360         be_add_reload(env, to_spill, before, reload_cls, allow_remat);
 361 }
 362
 363 void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block,
 364                            int pos,     const arch_register_class_t *reload_cls,
 365                            int allow_remat)
 366 {
 367         ir_node *before = get_block_insertion_point(block, pos);
 368         be_add_reload(env, to_spill, before, reload_cls, allow_remat);
 369 }
 370
 371 void be_spill_phi(spill_env_t *env, ir_node *node)
 372 {
 373         ir_node *block;
 374         spill_info_t* spill;
 375         int i, arity;
 376
 377         assert(is_Phi(node));
 378
 379         ir_nodeset_insert(&env->mem_phis, node);
 380
 381         /* create spills for the phi arguments */
 382         block = get_nodes_block(node);
 383         spill = get_spillinfo(env, node);
 384         for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
 385                 ir_node *arg        = get_irn_n(node, i);
 386                 ir_node *insert;
 387                 //get_spillinfo(env, arg);
 388
 389                 /* some backends have virtual noreg/unknown nodes that are not scheduled
 390                  * and simply always available. */
 391                 if(!sched_is_scheduled(arg)) {
 392                         ir_node *pred_block = get_Block_cfgpred_block(block, i);
 393                         insert = be_get_end_of_block_insertion_point(pred_block);
 394                 } else {
 395                         insert = skip_keeps_phis(arg);
 396                 }
 397
 398                 be_add_spill(env, arg, insert);
 399         }
 400 }
 401
 402 /*
 403  *   ____                _         ____        _ _ _
 404  *  / ___|_ __ ___  __ _| |_ ___  / ___| _ __ (_) | |___
 405  * | |   | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
 406  * | |___| | |  __/ (_| | ||  __/  ___) | |_) | | | \__ \
 407  *  \____|_|  \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
 408  *                                      |_|
 409  */
 410
 411 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo);
 412
 413 /**
 414  * Creates a spill.
 415  *
 416  * @param senv      the spill environment
 417  * @param irn       the node that should be spilled
 418  * @param ctx_irn   an user of the spilled node
 419  *
 420  * @return a be_Spill node
 421  */
 422 static void spill_irn(spill_env_t *env, spill_info_t *spillinfo)
 423 {
 424         ir_node *to_spill = spillinfo->to_spill;
 425         spill_t *spill;
 426
 427         /* determine_spill_costs must have been run before */
 428         assert(spillinfo->spill_costs >= 0);
 429
 430         /* some backends have virtual noreg/unknown nodes that are not scheduled
 431          * and simply always available. */
 432         if(!sched_is_scheduled(to_spill)) {
 433                 /* override spillinfos or create a new one */
 434                 spillinfo->spills->spill = new_NoMem();
 435                 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
 436                 return;
 437         }
 438
 439         DBG((dbg, LEVEL_1, "spilling %+F ... ", to_spill));
 440         spill = spillinfo->spills;
 441         for( ; spill != NULL; spill = spill->next) {
 442                 ir_node *block  = get_block(spill->before);
 443                 ir_node *before = spill->before;
 444
 445                 /* place all spills before the reloads (as we can't guarantee the
 446                  * same order as the be_add_spill and be_add_reload calls */
 447                 while(get_irn_idx(sched_prev(before)) > env->new_nodes_idx) {
 448                         before = sched_prev(before);
 449                 }
 450
 451                 spill->spill    = be_spill(env->arch_env, block, to_spill);
 452                 sched_add_before(before, spill->spill);
 453                 DB((dbg, LEVEL_1, "\t%+F before %+F\n", spill->spill, before));
 454 #ifdef FIRM_STATISTICS
 455                 env->spill_count++;
 456 #endif
 457         }
 458         DBG((dbg, LEVEL_1, "\n"));
 459 }
 460
 461 static void spill_node(spill_env_t *env, spill_info_t *spillinfo);
 462
 463 /**
 464  * If the first usage of a Phi result would be out of memory
 465  * there is no sense in allocating a register for it.
 466  * Thus we spill it and all its operands to the same spill slot.
 467  * Therefore the phi/dataB becomes a phi/Memory
 468  *
 469  * @param senv      the spill environment
 470  * @param phi       the Phi node that should be spilled
 471  * @param ctx_irn   an user of the spilled node
 472  */
 473 static void spill_phi(spill_env_t *env, spill_info_t *spillinfo)
 474 {
 475         ir_graph *irg   = env->irg;
 476         ir_node  *phi   = spillinfo->to_spill;
 477         ir_node  *block = get_nodes_block(phi);
 478         ir_node  *unknown;
 479         ir_node **ins;
 480         spill_t  *spill;
 481         int       i;
 482         int       arity;
 483
 484         assert(is_Phi(phi));
 485         assert(!get_opt_cse());
 486         DBG((dbg, LEVEL_1, "spilling Phi %+F:\n", phi));
 487
 488         /* build a new PhiM */
 489         arity   = get_irn_arity(phi);
 490         ins     = alloca(sizeof(ir_node*) * arity);
 491         unknown = new_r_Unknown(irg, mode_M);
 492         for(i = 0; i < arity; ++i) {
 493                 ins[i] = unknown;
 494         }
 495
 496         /* override or replace spills list... */
 497         spill         = obstack_alloc(&env->obst, sizeof(spill[0]));
 498         spill->before = skip_keeps_phis(phi);
 499         spill->spill  = new_r_Phi(irg, block, arity, ins, mode_M);
 500         spill->next   = NULL;
 501
 502         spillinfo->spills = spill;
 503 #ifdef FIRM_STATISTICS
 504         env->spilled_phi_count++;
 505 #endif
 506
 507         for(i = 0; i < arity; ++i) {
 508                 ir_node      *arg      = get_irn_n(phi, i);
 509                 spill_info_t *arg_info = get_spillinfo(env, arg);
 510
 511                 determine_spill_costs(env, arg_info);
 512                 spill_node(env, arg_info);
 513
 514                 set_irn_n(spill->spill, i, arg_info->spills->spill);
 515         }
 516         DBG((dbg, LEVEL_1, "... done spilling Phi %+F, created PhiM %+F\n", phi,
 517              spill->spill));
 518 }
 519
 520 /**
 521  * Spill a node.
 522  *
 523  * @param senv      the spill environment
 524  * @param to_spill  the node that should be spilled
 525  */
 526 static void spill_node(spill_env_t *env, spill_info_t *spillinfo)
 527 {
 528         ir_node *to_spill;
 529
 530         /* node is already spilled */
 531         if(spillinfo->spills != NULL && spillinfo->spills->spill != NULL)
 532                 return;
 533
 534         to_spill = spillinfo->to_spill;
 535
 536         if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
 537                 spill_phi(env, spillinfo);
 538         } else {
 539                 spill_irn(env, spillinfo);
 540         }
 541 }
 542
 543 /*
 544  *
 545  *  ____                      _            _       _ _
 546  * |  _ \ ___ _ __ ___   __ _| |_ ___ _ __(_) __ _| (_)_______
 547  * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_  / _ \
 548  * |  _ <  __/ | | | | | (_| | ||  __/ |  | | (_| | | |/ /  __/
 549  * |_| \_\___|_| |_| |_|\__,_|\__\___|_|  |_|\__,_|_|_/___\___|
 550  *
 551  */
 552
 553 /**
 554  * Tests whether value @p arg is available before node @p reloader
 555  * @returns 1 if value is available, 0 otherwise
 556  */
 557 static int is_value_available(spill_env_t *env, const ir_node *arg,
 558                               const ir_node *reloader)
 559 {
 560         if(is_Unknown(arg) || arg == new_NoMem())
 561                 return 1;
 562
 563         if(be_is_Spill(arg))
 564                 return 1;
 565
 566         if(arg == get_irg_frame(env->irg))
 567                 return 1;
 568
 569         /* hack for now (happens when command should be inserted at end of block) */
 570         if(is_Block(reloader)) {
 571                 return 0;
 572         }
 573
 574         /*
 575          * Ignore registers are always available
 576          */
 577         if(arch_irn_is(env->arch_env, arg, ignore)) {
 578                 return 1;
 579         }
 580
 581         /* the following test does not work while spilling,
 582          * because the liveness info is not adapted yet to the effects of the
 583          * additional spills/reloads.
 584          */
 585 #if 0
 586         /* we want to remat before the insn reloader
 587          * thus an arguments is alive if
 588          *   - it interferes with the reloaders result
 589          *   - or it is (last-) used by reloader itself
 590          */
 591         if (values_interfere(env->birg->lv, reloader, arg)) {
 592                 return 1;
 593         }
 594
 595         arity = get_irn_arity(reloader);
 596         for (i = 0; i < arity; ++i) {
 597                 ir_node *rel_arg = get_irn_n(reloader, i);
 598                 if (rel_arg == arg)
 599                         return 1;
 600         }
 601 #endif
 602
 603         return 0;
 604 }
 605
 606 /**
 607  * Checks whether the node can principally be rematerialized
 608  */
 609 static int is_remat_node(spill_env_t *env, const ir_node *node)
 610 {
 611         const arch_env_t *arch_env = env->arch_env;
 612
 613         assert(!be_is_Spill(node));
 614
 615         if(arch_irn_is(arch_env, node, rematerializable))
 616                 return 1;
 617
 618         return 0;
 619 }
 620
 621 /**
 622  * Check if a node is rematerializable. This tests for the following conditions:
 623  *
 624  * - The node itself is rematerializable
 625  * - All arguments of the node are available or also rematerialisable
 626  * - The costs for the rematerialisation operation is less or equal a limit
 627  *
 628  * Returns the costs needed for rematerialisation or something
 629  * >= REMAT_COST_INFINITE if remat is not possible.
 630  */
 631 static int check_remat_conditions_costs(spill_env_t *env,
 632                 const ir_node *spilled, const ir_node *reloader, int parentcosts)
 633 {
 634         int i, arity;
 635         int argremats;
 636         int costs = 0;
 637
 638         if(!is_remat_node(env, spilled))
 639                 return REMAT_COST_INFINITE;
 640
 641         if(be_is_Reload(spilled)) {
 642                 costs += 2;
 643         } else {
 644                 costs += arch_get_op_estimated_cost(env->arch_env, spilled);
 645         }
 646         if(parentcosts + costs >= env->reload_cost + env->spill_cost) {
 647                 return REMAT_COST_INFINITE;
 648         }
 649         if(arch_irn_is(env->arch_env, spilled, modify_flags)) {
 650                 return REMAT_COST_INFINITE;
 651         }
 652
 653         argremats = 0;
 654         for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
 655                 ir_node *arg = get_irn_n(spilled, i);
 656
 657                 if(is_value_available(env, arg, reloader))
 658                         continue;
 659
 660                 /* we have to rematerialize the argument as well */
 661                 if(argremats >= 1) {
 662                         /* we only support rematerializing 1 argument at the moment,
 663                          * so that we don't have to care about register pressure
 664                          */
 665                         return REMAT_COST_INFINITE;
 666                 }
 667                 argremats++;
 668
 669                 costs += check_remat_conditions_costs(env, arg, reloader,
 670                                                       parentcosts + costs);
 671                 if(parentcosts + costs >= env->reload_cost + env->spill_cost)
 672                         return REMAT_COST_INFINITE;
 673         }
 674
 675         return costs;
 676 }
 677
 678 /**
 679  * Re-materialize a node.
 680  *
 681  * @param senv      the spill environment
 682  * @param spilled   the node that was spilled
 683  * @param reloader  a irn that requires a reload
 684  */
 685 static ir_node *do_remat(spill_env_t *env, ir_node *spilled, ir_node *reloader)
 686 {
 687         int i, arity;
 688         ir_node *res;
 689         ir_node *bl;
 690         ir_node **ins;
 691
 692         if(is_Block(reloader)) {
 693                 bl = reloader;
 694         } else {
 695                 bl = get_nodes_block(reloader);
 696         }
 697
 698         ins = alloca(get_irn_arity(spilled) * sizeof(ins[0]));
 699         for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
 700                 ir_node *arg = get_irn_n(spilled, i);
 701
 702                 if(is_value_available(env, arg, reloader)) {
 703                         ins[i] = arg;
 704                 } else {
 705                         ins[i] = do_remat(env, arg, reloader);
 706 #ifdef FIRM_STATISTICS
 707                         /* don't count the recursive call as remat */
 708                         env->remat_count--;
 709 #endif
 710                 }
 711         }
 712
 713         /* create a copy of the node */
 714         res = new_ir_node(get_irn_dbg_info(spilled), env->irg, bl,
 715                           get_irn_op(spilled), get_irn_mode(spilled),
 716                           get_irn_arity(spilled), ins);
 717         copy_node_attr(spilled, res);
 718         new_backedge_info(res);
 719
 720         DBG((dbg, LEVEL_1, "Insert remat %+F of %+F before reloader %+F\n", res, spilled, reloader));
 721
 722         if (! is_Proj(res)) {
 723                 /* insert in schedule */
 724                 sched_reset(res);
 725                 sched_add_before(reloader, res);
 726 #ifdef FIRM_STATISTICS
 727                 env->remat_count++;
 728 #endif
 729         }
 730
 731         return res;
 732 }
 733
 734 double be_get_spill_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
 735 {
 736         ir_node *block = get_nodes_block(before);
 737         double   freq  = get_block_execfreq(env->exec_freq, block);
 738         (void) to_spill;
 739
 740         return env->spill_cost * freq;
 741 }
 742
 743 unsigned be_get_reload_costs_no_weight(spill_env_t *env, const ir_node *to_spill,
 744                                        const ir_node *before)
 745 {
 746         if(be_do_remats) {
 747                 /* is the node rematerializable? */
 748                 unsigned costs = check_remat_conditions_costs(env, to_spill, before, 0);
 749                 if(costs < (unsigned) env->reload_cost)
 750                         return costs;
 751         }
 752
 753         return env->reload_cost;
 754 }
 755
 756 double be_get_reload_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
 757 {
 758         ir_node      *block = get_nodes_block(before);
 759         double        freq  = get_block_execfreq(env->exec_freq, block);
 760
 761         if(be_do_remats) {
 762                 /* is the node rematerializable? */
 763                 int costs = check_remat_conditions_costs(env, to_spill, before, 0);
 764                 if(costs < env->reload_cost)
 765                         return costs * freq;
 766         }
 767
 768         return env->reload_cost * freq;
 769 }
 770
 771 int be_is_rematerializable(spill_env_t *env, const ir_node *to_remat,
 772                            const ir_node *before)
 773 {
 774         return check_remat_conditions_costs(env, to_remat, before, 0) < REMAT_COST_INFINITE;
 775 }
 776
 777 double be_get_reload_costs_on_edge(spill_env_t *env, ir_node *to_spill,
 778                                    ir_node *block, int pos)
 779 {
 780         ir_node *before = get_block_insertion_point(block, pos);
 781         return be_get_reload_costs(env, to_spill, before);
 782 }
 783
 784 /*
 785  *  ___                     _     ____      _                 _
 786  * |_ _|_ __  ___  ___ _ __| |_  |  _ \ ___| | ___   __ _  __| |___
 787  *  | || '_ \/ __|/ _ \ '__| __| | |_) / _ \ |/ _ \ / _` |/ _` / __|
 788  *  | || | | \__ \  __/ |  | |_  |  _ <  __/ | (_) | (_| | (_| \__ \
 789  * |___|_| |_|___/\___|_|   \__| |_| \_\___|_|\___/ \__,_|\__,_|___/
 790  *
 791  */
 792
 793 /**
 794  * analyzes how to best spill a node and determine costs for that
 795  */
 796 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo)
 797 {
 798         ir_node *to_spill = spillinfo->to_spill;
 799         ir_node *spill_block;
 800         spill_t *spill;
 801         double   spill_execfreq;
 802
 803         /* already calculated? */
 804         if(spillinfo->spill_costs >= 0)
 805                 return;
 806
 807         assert(! arch_irn_is(env->arch_env, to_spill, dont_spill));
 808         assert(!be_is_Reload(to_spill));
 809
 810         /* some backends have virtual noreg/unknown nodes that are not scheduled
 811          * and simply always available.
 812          * TODO: this is kinda hairy, the NoMem is correct for an Unknown as Phi
 813          * predecessor (of a PhiM) but this test might match other things too...
 814          */
 815         if(!sched_is_scheduled(to_spill)) {
 816                 /* override spillinfos or create a new one */
 817                 spill_t *spill = obstack_alloc(&env->obst, sizeof(spill[0]));
 818                 spill->before  = NULL;
 819                 spill->next    = NULL;
 820                 spill->spill   = new_NoMem();
 821
 822                 spillinfo->spills      = spill;
 823                 spillinfo->spill_costs = 0;
 824
 825                 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
 826                 return;
 827         }
 828
 829         spill_block    = get_nodes_block(to_spill);
 830         spill_execfreq = get_block_execfreq(env->exec_freq, spill_block);
 831
 832         if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
 833                 /* TODO calculate correct costs...
 834                  * (though we can't remat this node anyway so no big problem) */
 835                 spillinfo->spill_costs = env->spill_cost * spill_execfreq;
 836                 return;
 837         }
 838
 839         if(spillinfo->spills != NULL) {
 840                 spill_t *s;
 841                 double   spills_execfreq;
 842
 843                 /* calculate sum of executaion frequencies of individual spills */
 844                 spills_execfreq = 0;
 845                 s               = spillinfo->spills;
 846                 for( ; s != NULL; s = s->next) {
 847                         ir_node *spill_block = s->before;
 848                         double   freq;
 849
 850                         if(!is_Block(spill_block)) {
 851                                 spill_block = get_nodes_block(spill_block);
 852                         }
 853                         freq = get_block_execfreq(env->exec_freq, spill_block);
 854
 855                         spills_execfreq += freq;
 856                 }
 857
 858                 DB((dbg, LEVEL_1, "%+F: latespillcosts %f after def: %f\n", to_spill,
 859                     spills_execfreq * env->spill_cost,
 860                     spill_execfreq * env->spill_cost));
 861
 862                 /* multi-/latespill is advantageous -> return*/
 863                 if(spills_execfreq < spill_execfreq) {
 864                         DB((dbg, LEVEL_1, "use latespills for %+F\n", to_spill));
 865                         spillinfo->spill_costs = spills_execfreq * env->spill_cost;
 866                         return;
 867                 }
 868         }
 869
 870         /* override spillinfos or create a new one */
 871         spill         = obstack_alloc(&env->obst, sizeof(spill[0]));
 872         spill->before = skip_keeps_phis(to_spill);
 873         spill->next   = NULL;
 874         spill->spill  = NULL;
 875
 876         spillinfo->spills      = spill;
 877         spillinfo->spill_costs = spill_execfreq * env->spill_cost;
 878         DB((dbg, LEVEL_1, "spill %+F after definition\n", to_spill));
 879 }
 880
 881 void be_insert_spills_reloads(spill_env_t *env)
 882 {
 883         ir_graph              *irg       = env->irg;
 884         const arch_env_t      *arch_env  = env->arch_env;
 885         const ir_exec_freq    *exec_freq = env->exec_freq;
 886         spill_info_t          *si;
 887         ir_nodeset_iterator_t  iter;
 888         ir_node               *node;
 889
 890         BE_TIMER_PUSH(t_ra_spill_apply);
 891
 892         env->new_nodes_idx = get_irg_last_idx(irg);
 893
 894         /* create all phi-ms first, this is needed so, that phis, hanging on
 895            spilled phis work correctly */
 896         foreach_ir_nodeset(&env->mem_phis, node, iter) {
 897                 spill_info_t *info = get_spillinfo(env, node);
 898                 spill_node(env, info);
 899         }
 900
 901         /* process each spilled node */
 902         for (si = set_first(env->spills); si; si = set_next(env->spills)) {
 903                 reloader_t *rld;
 904                 ir_node  *to_spill        = si->to_spill;
 905                 ir_mode  *mode            = get_irn_mode(to_spill);
 906                 ir_node **copies          = NEW_ARR_F(ir_node*, 0);
 907                 double    all_remat_costs = 0; /** costs when we would remat all nodes */
 908                 int       force_remat     = 0;
 909
 910                 DBG((dbg, LEVEL_1, "\nhandling all reloaders of %+F:\n", to_spill));
 911
 912                 determine_spill_costs(env, si);
 913
 914                 /* determine possibility of rematerialisations */
 915                 if(be_do_remats) {
 916                         /* calculate cost savings for each indivial value when it would
 917                            be rematted instead of reloaded */
 918                         for (rld = si->reloaders; rld != NULL; rld = rld->next) {
 919                                 double   freq;
 920                                 int      remat_cost;
 921                                 int      remat_cost_delta;
 922                                 ir_node *block;
 923                                 ir_node *reloader = rld->reloader;
 924
 925                                 if(rld->rematted_node != NULL) {
 926                                         DBG((dbg, LEVEL_2, "\tforced remat %+F before %+F\n",
 927                                              rld->rematted_node, reloader));
 928                                         continue;
 929                                 }
 930                                 if(rld->remat_cost_delta >= REMAT_COST_INFINITE) {
 931                                         DBG((dbg, LEVEL_2, "\treload before %+F is forbidden\n",
 932                                              reloader));
 933                                         all_remat_costs = REMAT_COST_INFINITE;
 934                                         continue;
 935                                 }
 936
 937                                 remat_cost  = check_remat_conditions_costs(env, to_spill,
 938                                                                            reloader, 0);
 939                                 if(remat_cost >= REMAT_COST_INFINITE) {
 940                                         DBG((dbg, LEVEL_2, "\tremat before %+F not possible\n",
 941                                              reloader));
 942                                         rld->remat_cost_delta = REMAT_COST_INFINITE;
 943                                         all_remat_costs       = REMAT_COST_INFINITE;
 944                                         continue;
 945                                 }
 946
 947                                 remat_cost_delta      = remat_cost - env->reload_cost;
 948                                 rld->remat_cost_delta = remat_cost_delta;
 949                                 block                 = is_Block(reloader) ? reloader : get_nodes_block(reloader);
 950                                 freq                  = get_block_execfreq(exec_freq, block);
 951                                 all_remat_costs      += remat_cost_delta * freq;
 952                                 DBG((dbg, LEVEL_2, "\tremat costs delta before %+F: "
 953                                      "%d (rel %f)\n", reloader, remat_cost_delta,
 954                                      remat_cost_delta * freq));
 955                         }
 956                         if(all_remat_costs < REMAT_COST_INFINITE) {
 957                                 /* we don't need the costs for the spill if we can remat
 958                                    all reloaders */
 959                                 all_remat_costs -= si->spill_costs;
 960
 961                                 DBG((dbg, LEVEL_2, "\tspill costs %d (rel %f)\n",
 962                                      env->spill_cost, si->spill_costs));
 963                         }
 964
 965                         if(all_remat_costs < 0) {
 966                                 DBG((dbg, LEVEL_1, "\nforcing remats of all reloaders (%f)\n",
 967                                      all_remat_costs));
 968                                 force_remat = 1;
 969                         }
 970                 }
 971
 972                 /* go through all reloads for this spill */
 973                 for (rld = si->reloaders; rld != NULL; rld = rld->next) {
 974                         ir_node *copy; /* a reload is a "copy" of the original value */
 975
 976                         if (rld->rematted_node != NULL) {
 977                                 copy = rld->rematted_node;
 978                                 sched_add_before(rld->reloader, copy);
 979                         } else if (be_do_remats &&
 980                                         (force_remat || rld->remat_cost_delta < 0)) {
 981                                 copy = do_remat(env, to_spill, rld->reloader);
 982                         } else {
 983                                 /* make sure we have a spill */
 984                                 spill_node(env, si);
 985
 986                                 /* create a reload, use the first spill for now SSA
 987                                  * reconstruction for memory comes below */
 988                                 assert(si->spills != NULL);
 989                                 copy = be_reload(arch_env, si->reload_cls, rld->reloader, mode,
 990                                                  si->spills->spill);
 991 #ifdef FIRM_STATISTICS
 992                                 env->reload_count++;
 993 #endif
 994                         }
 995
 996                         DBG((dbg, LEVEL_1, " %+F of %+F before %+F\n",
 997                              copy, to_spill, rld->reloader));
 998                         ARR_APP1(ir_node*, copies, copy);
 999                 }
1000
1001                 /* if we had any reloads or remats, then we need to reconstruct the
1002                  * SSA form for the spilled value */
1003                 if (ARR_LEN(copies) > 0) {
1004                         be_ssa_construction_env_t senv;
1005                         /* be_lv_t *lv = be_get_birg_liveness(env->birg); */
1006
1007                         be_ssa_construction_init(&senv, env->birg);
1008                         be_ssa_construction_add_copy(&senv, to_spill);
1009                         be_ssa_construction_add_copies(&senv, copies, ARR_LEN(copies));
1010                         be_ssa_construction_fix_users(&senv, to_spill);
1011
1012 #if 0
1013                         /* no need to enable this as long as we invalidate liveness
1014                            after this function... */
1015                         be_ssa_construction_update_liveness_phis(&senv);
1016                         be_liveness_update(to_spill);
1017                         len = ARR_LEN(copies);
1018                         for(i = 0; i < len; ++i) {
1019                                 be_liveness_update(lv, copies[i]);
1020                         }
1021 #endif
1022                         be_ssa_construction_destroy(&senv);
1023                 }
1024                 /* need to reconstruct SSA form if we had multiple spills */
1025                 if (si->spills != NULL && si->spills->next != NULL) {
1026                         spill_t *spill;
1027                         int      spill_count = 0;
1028
1029                         be_ssa_construction_env_t senv;
1030
1031                         be_ssa_construction_init(&senv, env->birg);
1032                         spill = si->spills;
1033                         for( ; spill != NULL; spill = spill->next) {
1034                                 /* maybe we rematerialized the value and need no spill */
1035                                 if(spill->spill == NULL)
1036                                         continue;
1037                                 be_ssa_construction_add_copy(&senv, spill->spill);
1038                                 spill_count++;
1039                         }
1040                         if(spill_count > 1) {
1041                                 /* all reloads are attached to the first spill, fix them now */
1042                                 be_ssa_construction_fix_users(&senv, si->spills->spill);
1043                         }
1044
1045                         be_ssa_construction_destroy(&senv);
1046                 }
1047
1048                 DEL_ARR_F(copies);
1049                 si->reloaders = NULL;
1050         }
1051
1052         stat_ev_dbl("spill_spills", env->spill_count);
1053         stat_ev_dbl("spill_reloads", env->reload_count);
1054         stat_ev_dbl("spill_remats", env->remat_count);
1055         stat_ev_dbl("spill_spilled_phis", env->spilled_phi_count);
1056
1057         /* Matze: In theory be_ssa_construction should take care of the liveness...
1058          * try to disable this again in the future */
1059         be_liveness_invalidate(env->birg->lv);
1060
1061         be_remove_dead_nodes_from_schedule(env->birg);
1062
1063         BE_TIMER_POP(t_ra_spill_apply);
1064 }
1065
1066 void be_init_spill(void)
1067 {
1068         FIRM_DBG_REGISTER(dbg, "firm.be.spill");
1069 }
1070
1071 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spill);