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->spill_cost;
 166         env->reload_cost    = arch_env->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         /* Just for safety make sure that we do not insert the spill in front of a phi */
 209         for (; is_Phi(before); before = sched_next(before));
 210
 211         /* spills that are dominated by others are not needed */
 212         last = NULL;
 213         s    = spill_info->spills;
 214         for( ; s != NULL; s = s->next) {
 215                 /* no need to add this spill if it is dominated by another */
 216                 if(value_dominates(s->before, before)) {
 217                         DB((dbg, LEVEL_1, "...dominated by %+F, not added\n", s->before));
 218                         return;
 219                 }
 220                 /* remove spills that we dominate */
 221                 if(value_dominates(before, s->before)) {
 222                         DB((dbg, LEVEL_1, "...remove old spill at %+F\n", s->before));
 223                         if(last != NULL) {
 224                                 last->next         = s->next;
 225                         } else {
 226                                 spill_info->spills = s->next;
 227                         }
 228                 } else {
 229                         last = s;
 230                 }
 231         }
 232
 233         spill         = obstack_alloc(&env->obst, sizeof(spill[0]));
 234         spill->before = before;
 235         spill->next   = spill_info->spills;
 236         spill->spill  = NULL;
 237
 238         spill_info->spills = spill;
 239 #endif
 240 }
 241
 242 void be_add_remat(spill_env_t *env, ir_node *to_spill, ir_node *before,
 243                   ir_node *rematted_node)
 244 {
 245         spill_info_t *spill_info;
 246         reloader_t *reloader;
 247
 248         spill_info = get_spillinfo(env, to_spill);
 249
 250         /* add the remat information */
 251         reloader                   = obstack_alloc(&env->obst, sizeof(reloader[0]));
 252         reloader->next             = spill_info->reloaders;
 253         reloader->reloader         = before;
 254         reloader->rematted_node    = rematted_node;
 255         reloader->remat_cost_delta = 0; /* We will never have a cost win over a
 256                                            reload since we're not even allowed to
 257                                            create a reload */
 258
 259         spill_info->reloaders  = reloader;
 260
 261         DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be rematerialized before %+F\n",
 262                 to_spill, before));
 263 }
 264
 265 void be_add_reload2(spill_env_t *env, ir_node *to_spill, ir_node *before,
 266                 ir_node *can_spill_after, const arch_register_class_t *reload_cls,
 267                 int allow_remat)
 268 {
 269         spill_info_t *info;
 270         reloader_t *rel;
 271
 272         assert(! arch_irn_is(env->arch_env, to_spill, dont_spill));
 273
 274         info = get_spillinfo(env, to_spill);
 275
 276         if (is_Phi(to_spill)) {
 277                 int i, arity;
 278
 279                 /* create spillinfos for the phi arguments */
 280                 for (i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
 281                         ir_node *arg = get_irn_n(to_spill, i);
 282                         get_spillinfo(env, arg);
 283                 }
 284         }
 285
 286         assert(!is_Proj(before) && !be_is_Keep(before));
 287
 288         /* put reload into list */
 289         rel                   = obstack_alloc(&env->obst, sizeof(rel[0]));
 290         rel->next             = info->reloaders;
 291         rel->reloader         = before;
 292         rel->rematted_node    = NULL;
 293         rel->can_spill_after  = can_spill_after;
 294         rel->remat_cost_delta = allow_remat ? 0 : REMAT_COST_INFINITE;
 295
 296         info->reloaders  = rel;
 297         assert(info->reload_cls == NULL || info->reload_cls == reload_cls);
 298         info->reload_cls = reload_cls;
 299
 300         DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be reloaded before %+F, may%s be rematerialized\n",
 301                 to_spill, before, allow_remat ? "" : " not"));
 302 }
 303
 304 void be_add_reload(spill_env_t *senv, ir_node *to_spill, ir_node *before,
 305                    const arch_register_class_t *reload_cls, int allow_remat)
 306 {
 307         be_add_reload2(senv, to_spill, before, to_spill, reload_cls, allow_remat);
 308
 309 }
 310
 311 ir_node *be_get_end_of_block_insertion_point(const ir_node *block)
 312 {
 313         ir_node *last = sched_last(block);
 314
 315         /* we might have keeps behind the jump... */
 316         while (be_is_Keep(last)) {
 317                 last = sched_prev(last);
 318                 assert(!sched_is_end(last));
 319         }
 320
 321         assert(is_cfop(last));
 322
 323         /* add the reload before the (cond-)jump */
 324         return last;
 325 }
 326
 327 static ir_node *skip_keeps_phis(ir_node *node)
 328 {
 329         node = sched_next(node);
 330         while(is_Phi(node) || be_is_Keep(node)) {
 331                 node = sched_next(node);
 332         }
 333         return node;
 334 }
 335
 336 /**
 337  * Returns the point at which you can insert a node that should be executed
 338  * before block @p block when coming from pred @p pos.
 339  */
 340 static ir_node *get_block_insertion_point(ir_node *block, int pos)
 341 {
 342         ir_node *predblock;
 343
 344         /* simply add the reload to the beginning of the block if we only have 1
 345          * predecessor. We don't need to check for phis as there can't be any in a
 346          * block with only 1 pred. */
 347         if(get_Block_n_cfgpreds(block) == 1) {
 348                 assert(!is_Phi(sched_first(block)));
 349                 return sched_first(block);
 350         }
 351
 352         /* We have to reload the value in pred-block */
 353         predblock = get_Block_cfgpred_block(block, pos);
 354         return be_get_end_of_block_insertion_point(predblock);
 355 }
 356
 357 void be_add_reload_at_end(spill_env_t *env, ir_node *to_spill,
 358                           const ir_node *block,
 359                           const arch_register_class_t *reload_cls,
 360                           int allow_remat)
 361 {
 362         ir_node *before = be_get_end_of_block_insertion_point(block);
 363         be_add_reload(env, to_spill, before, reload_cls, allow_remat);
 364 }
 365
 366 void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block,
 367                            int pos,     const arch_register_class_t *reload_cls,
 368                            int allow_remat)
 369 {
 370         ir_node *before = get_block_insertion_point(block, pos);
 371         be_add_reload(env, to_spill, before, reload_cls, allow_remat);
 372 }
 373
 374 void be_spill_phi(spill_env_t *env, ir_node *node)
 375 {
 376         ir_node *block;
 377         spill_info_t* spill;
 378         int i, arity;
 379
 380         assert(is_Phi(node));
 381
 382         ir_nodeset_insert(&env->mem_phis, node);
 383
 384         /* create spills for the phi arguments */
 385         block = get_nodes_block(node);
 386         spill = get_spillinfo(env, node);
 387         for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
 388                 ir_node *arg        = get_irn_n(node, i);
 389                 ir_node *insert;
 390                 //get_spillinfo(env, arg);
 391
 392                 /* some backends have virtual noreg/unknown nodes that are not scheduled
 393                  * and simply always available. */
 394                 if(!sched_is_scheduled(arg)) {
 395                         ir_node *pred_block = get_Block_cfgpred_block(block, i);
 396                         insert = be_get_end_of_block_insertion_point(pred_block);
 397                 } else {
 398                         insert = skip_keeps_phis(arg);
 399                 }
 400
 401                 be_add_spill(env, arg, insert);
 402         }
 403 }
 404
 405 /*
 406  *   ____                _         ____        _ _ _
 407  *  / ___|_ __ ___  __ _| |_ ___  / ___| _ __ (_) | |___
 408  * | |   | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
 409  * | |___| | |  __/ (_| | ||  __/  ___) | |_) | | | \__ \
 410  *  \____|_|  \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
 411  *                                      |_|
 412  */
 413
 414 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo);
 415
 416 /**
 417  * Creates a spill.
 418  *
 419  * @param senv      the spill environment
 420  * @param irn       the node that should be spilled
 421  * @param ctx_irn   an user of the spilled node
 422  *
 423  * @return a be_Spill node
 424  */
 425 static void spill_irn(spill_env_t *env, spill_info_t *spillinfo)
 426 {
 427         ir_node *to_spill = spillinfo->to_spill;
 428         spill_t *spill;
 429
 430         /* determine_spill_costs must have been run before */
 431         assert(spillinfo->spill_costs >= 0);
 432
 433         /* some backends have virtual noreg/unknown nodes that are not scheduled
 434          * and simply always available. */
 435         if(!sched_is_scheduled(to_spill)) {
 436                 /* override spillinfos or create a new one */
 437                 spillinfo->spills->spill = new_NoMem();
 438                 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
 439                 return;
 440         }
 441
 442         DBG((dbg, LEVEL_1, "spilling %+F ... \n", to_spill));
 443         spill = spillinfo->spills;
 444         for( ; spill != NULL; spill = spill->next) {
 445                 ir_node *block  = get_block(spill->before);
 446                 ir_node *before = spill->before;
 447
 448                 /* place all spills before the reloads (as we can't guarantee the
 449                  * same order as the be_add_spill and be_add_reload calls.
 450                  * Also make sure that we do not run into Phis when going up. */
 451                 while(get_irn_idx(sched_prev(before)) > env->new_nodes_idx && !is_Phi(sched_prev(before))) {
 452                         before = sched_prev(before);
 453                 }
 454
 455                 spill->spill    = be_spill(env->arch_env, block, to_spill);
 456                 sched_add_before(before, spill->spill);
 457                 DB((dbg, LEVEL_1, "\t%+F before %+F\n", spill->spill, before));
 458 #ifdef FIRM_STATISTICS
 459                 env->spill_count++;
 460 #endif
 461         }
 462         DBG((dbg, LEVEL_1, "\n"));
 463 }
 464
 465 static void spill_node(spill_env_t *env, spill_info_t *spillinfo);
 466
 467 /**
 468  * If the first usage of a Phi result would be out of memory
 469  * there is no sense in allocating a register for it.
 470  * Thus we spill it and all its operands to the same spill slot.
 471  * Therefore the phi/dataB becomes a phi/Memory
 472  *
 473  * @param senv      the spill environment
 474  * @param phi       the Phi node that should be spilled
 475  * @param ctx_irn   an user of the spilled node
 476  */
 477 static void spill_phi(spill_env_t *env, spill_info_t *spillinfo)
 478 {
 479         ir_graph *irg   = env->irg;
 480         ir_node  *phi   = spillinfo->to_spill;
 481         ir_node  *block = get_nodes_block(phi);
 482         ir_node  *unknown;
 483         ir_node **ins;
 484         spill_t  *spill;
 485         int       i;
 486         int       arity;
 487
 488         assert(is_Phi(phi));
 489         assert(!get_opt_cse());
 490         DBG((dbg, LEVEL_1, "spilling Phi %+F:\n", phi));
 491
 492         /* build a new PhiM */
 493         arity   = get_irn_arity(phi);
 494         ins     = alloca(sizeof(ir_node*) * arity);
 495         unknown = new_r_Unknown(irg, mode_M);
 496         for(i = 0; i < arity; ++i) {
 497                 ins[i] = unknown;
 498         }
 499
 500         /* override or replace spills list... */
 501         spill         = obstack_alloc(&env->obst, sizeof(spill[0]));
 502         spill->before = skip_keeps_phis(phi);
 503         spill->spill  = new_r_Phi(irg, block, arity, ins, mode_M);
 504         spill->next   = NULL;
 505
 506         spillinfo->spills = spill;
 507 #ifdef FIRM_STATISTICS
 508         env->spilled_phi_count++;
 509 #endif
 510
 511         for(i = 0; i < arity; ++i) {
 512                 ir_node      *arg      = get_irn_n(phi, i);
 513                 spill_info_t *arg_info = get_spillinfo(env, arg);
 514
 515                 determine_spill_costs(env, arg_info);
 516                 spill_node(env, arg_info);
 517
 518                 set_irn_n(spill->spill, i, arg_info->spills->spill);
 519         }
 520         DBG((dbg, LEVEL_1, "... done spilling Phi %+F, created PhiM %+F\n", phi,
 521              spill->spill));
 522 }
 523
 524 /**
 525  * Spill a node.
 526  *
 527  * @param senv      the spill environment
 528  * @param to_spill  the node that should be spilled
 529  */
 530 static void spill_node(spill_env_t *env, spill_info_t *spillinfo)
 531 {
 532         ir_node *to_spill;
 533
 534         /* node is already spilled */
 535         if(spillinfo->spills != NULL && spillinfo->spills->spill != NULL)
 536                 return;
 537
 538         to_spill = spillinfo->to_spill;
 539
 540         if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
 541                 spill_phi(env, spillinfo);
 542         } else {
 543                 spill_irn(env, spillinfo);
 544         }
 545 }
 546
 547 /*
 548  *
 549  *  ____                      _            _       _ _
 550  * |  _ \ ___ _ __ ___   __ _| |_ ___ _ __(_) __ _| (_)_______
 551  * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_  / _ \
 552  * |  _ <  __/ | | | | | (_| | ||  __/ |  | | (_| | | |/ /  __/
 553  * |_| \_\___|_| |_| |_|\__,_|\__\___|_|  |_|\__,_|_|_/___\___|
 554  *
 555  */
 556
 557 /**
 558  * Tests whether value @p arg is available before node @p reloader
 559  * @returns 1 if value is available, 0 otherwise
 560  */
 561 static int is_value_available(spill_env_t *env, const ir_node *arg,
 562                               const ir_node *reloader)
 563 {
 564         if(is_Unknown(arg) || arg == new_NoMem())
 565                 return 1;
 566
 567         if(be_is_Spill(arg))
 568                 return 1;
 569
 570         if(arg == get_irg_frame(env->irg))
 571                 return 1;
 572
 573         /* hack for now (happens when command should be inserted at end of block) */
 574         if(is_Block(reloader)) {
 575                 return 0;
 576         }
 577
 578         /*
 579          * Ignore registers are always available
 580          */
 581         if(arch_irn_is(env->arch_env, arg, ignore)) {
 582                 return 1;
 583         }
 584
 585         /* the following test does not work while spilling,
 586          * because the liveness info is not adapted yet to the effects of the
 587          * additional spills/reloads.
 588          */
 589 #if 0
 590         /* we want to remat before the insn reloader
 591          * thus an arguments is alive if
 592          *   - it interferes with the reloaders result
 593          *   - or it is (last-) used by reloader itself
 594          */
 595         if (values_interfere(env->birg->lv, reloader, arg)) {
 596                 return 1;
 597         }
 598
 599         arity = get_irn_arity(reloader);
 600         for (i = 0; i < arity; ++i) {
 601                 ir_node *rel_arg = get_irn_n(reloader, i);
 602                 if (rel_arg == arg)
 603                         return 1;
 604         }
 605 #endif
 606
 607         return 0;
 608 }
 609
 610 /**
 611  * Checks whether the node can principally be rematerialized
 612  */
 613 static int is_remat_node(spill_env_t *env, const ir_node *node)
 614 {
 615         const arch_env_t *arch_env = env->arch_env;
 616
 617         assert(!be_is_Spill(node));
 618
 619         if(arch_irn_is(arch_env, node, rematerializable))
 620                 return 1;
 621
 622         return 0;
 623 }
 624
 625 /**
 626  * Check if a node is rematerializable. This tests for the following conditions:
 627  *
 628  * - The node itself is rematerializable
 629  * - All arguments of the node are available or also rematerialisable
 630  * - The costs for the rematerialisation operation is less or equal a limit
 631  *
 632  * Returns the costs needed for rematerialisation or something
 633  * >= REMAT_COST_INFINITE if remat is not possible.
 634  */
 635 static int check_remat_conditions_costs(spill_env_t *env,
 636                 const ir_node *spilled, const ir_node *reloader, int parentcosts)
 637 {
 638         int i, arity;
 639         int argremats;
 640         int costs = 0;
 641
 642         if(!is_remat_node(env, spilled))
 643                 return REMAT_COST_INFINITE;
 644
 645         if(be_is_Reload(spilled)) {
 646                 costs += 2;
 647         } else {
 648                 costs += arch_get_op_estimated_cost(env->arch_env, spilled);
 649         }
 650         if(parentcosts + costs >= env->reload_cost + env->spill_cost) {
 651                 return REMAT_COST_INFINITE;
 652         }
 653         if(arch_irn_is(env->arch_env, spilled, modify_flags)) {
 654                 return REMAT_COST_INFINITE;
 655         }
 656
 657         argremats = 0;
 658         for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
 659                 ir_node *arg = get_irn_n(spilled, i);
 660
 661                 if(is_value_available(env, arg, reloader))
 662                         continue;
 663
 664                 /* we have to rematerialize the argument as well */
 665                 if(argremats >= 1) {
 666                         /* we only support rematerializing 1 argument at the moment,
 667                          * so that we don't have to care about register pressure
 668                          */
 669                         return REMAT_COST_INFINITE;
 670                 }
 671                 argremats++;
 672
 673                 costs += check_remat_conditions_costs(env, arg, reloader,
 674                                                       parentcosts + costs);
 675                 if(parentcosts + costs >= env->reload_cost + env->spill_cost)
 676                         return REMAT_COST_INFINITE;
 677         }
 678
 679         return costs;
 680 }
 681
 682 /**
 683  * Re-materialize a node.
 684  *
 685  * @param senv      the spill environment
 686  * @param spilled   the node that was spilled
 687  * @param reloader  a irn that requires a reload
 688  */
 689 static ir_node *do_remat(spill_env_t *env, ir_node *spilled, ir_node *reloader)
 690 {
 691         int i, arity;
 692         ir_node *res;
 693         ir_node *bl;
 694         ir_node **ins;
 695
 696         if(is_Block(reloader)) {
 697                 bl = reloader;
 698         } else {
 699                 bl = get_nodes_block(reloader);
 700         }
 701
 702         ins = alloca(get_irn_arity(spilled) * sizeof(ins[0]));
 703         for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
 704                 ir_node *arg = get_irn_n(spilled, i);
 705
 706                 if(is_value_available(env, arg, reloader)) {
 707                         ins[i] = arg;
 708                 } else {
 709                         ins[i] = do_remat(env, arg, reloader);
 710 #ifdef FIRM_STATISTICS
 711                         /* don't count the recursive call as remat */
 712                         env->remat_count--;
 713 #endif
 714                 }
 715         }
 716
 717         /* create a copy of the node */
 718         res = new_ir_node(get_irn_dbg_info(spilled), env->irg, bl,
 719                           get_irn_op(spilled), get_irn_mode(spilled),
 720                           get_irn_arity(spilled), ins);
 721         copy_node_attr(spilled, res);
 722         new_backedge_info(res);
 723
 724         DBG((dbg, LEVEL_1, "Insert remat %+F of %+F before reloader %+F\n", res, spilled, reloader));
 725
 726         if (! is_Proj(res)) {
 727                 /* insert in schedule */
 728                 sched_reset(res);
 729                 sched_add_before(reloader, res);
 730 #ifdef FIRM_STATISTICS
 731                 env->remat_count++;
 732 #endif
 733         }
 734
 735         return res;
 736 }
 737
 738 double be_get_spill_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
 739 {
 740         ir_node *block = get_nodes_block(before);
 741         double   freq  = get_block_execfreq(env->exec_freq, block);
 742         (void) to_spill;
 743
 744         return env->spill_cost * freq;
 745 }
 746
 747 unsigned be_get_reload_costs_no_weight(spill_env_t *env, const ir_node *to_spill,
 748                                        const ir_node *before)
 749 {
 750         if(be_do_remats) {
 751                 /* is the node rematerializable? */
 752                 unsigned costs = check_remat_conditions_costs(env, to_spill, before, 0);
 753                 if(costs < (unsigned) env->reload_cost)
 754                         return costs;
 755         }
 756
 757         return env->reload_cost;
 758 }
 759
 760 double be_get_reload_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
 761 {
 762         ir_node      *block = get_nodes_block(before);
 763         double        freq  = get_block_execfreq(env->exec_freq, block);
 764
 765         if(be_do_remats) {
 766                 /* is the node rematerializable? */
 767                 int costs = check_remat_conditions_costs(env, to_spill, before, 0);
 768                 if(costs < env->reload_cost)
 769                         return costs * freq;
 770         }
 771
 772         return env->reload_cost * freq;
 773 }
 774
 775 int be_is_rematerializable(spill_env_t *env, const ir_node *to_remat,
 776                            const ir_node *before)
 777 {
 778         return check_remat_conditions_costs(env, to_remat, before, 0) < REMAT_COST_INFINITE;
 779 }
 780
 781 double be_get_reload_costs_on_edge(spill_env_t *env, ir_node *to_spill,
 782                                    ir_node *block, int pos)
 783 {
 784         ir_node *before = get_block_insertion_point(block, pos);
 785         return be_get_reload_costs(env, to_spill, before);
 786 }
 787
 788 /*
 789  *  ___                     _     ____      _                 _
 790  * |_ _|_ __  ___  ___ _ __| |_  |  _ \ ___| | ___   __ _  __| |___
 791  *  | || '_ \/ __|/ _ \ '__| __| | |_) / _ \ |/ _ \ / _` |/ _` / __|
 792  *  | || | | \__ \  __/ |  | |_  |  _ <  __/ | (_) | (_| | (_| \__ \
 793  * |___|_| |_|___/\___|_|   \__| |_| \_\___|_|\___/ \__,_|\__,_|___/
 794  *
 795  */
 796
 797 /**
 798  * analyzes how to best spill a node and determine costs for that
 799  */
 800 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo)
 801 {
 802         ir_node *to_spill = spillinfo->to_spill;
 803         ir_node *spill_block;
 804         spill_t *spill;
 805         double   spill_execfreq;
 806
 807         /* already calculated? */
 808         if(spillinfo->spill_costs >= 0)
 809                 return;
 810
 811         assert(! arch_irn_is(env->arch_env, to_spill, dont_spill));
 812         assert(!be_is_Reload(to_spill));
 813
 814         /* some backends have virtual noreg/unknown nodes that are not scheduled
 815          * and simply always available.
 816          * TODO: this is kinda hairy, the NoMem is correct for an Unknown as Phi
 817          * predecessor (of a PhiM) but this test might match other things too...
 818          */
 819         if(!sched_is_scheduled(to_spill)) {
 820                 /* override spillinfos or create a new one */
 821                 spill_t *spill = obstack_alloc(&env->obst, sizeof(spill[0]));
 822                 spill->before  = NULL;
 823                 spill->next    = NULL;
 824                 spill->spill   = new_NoMem();
 825
 826                 spillinfo->spills      = spill;
 827                 spillinfo->spill_costs = 0;
 828
 829                 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
 830                 return;
 831         }
 832
 833         spill_block    = get_nodes_block(to_spill);
 834         spill_execfreq = get_block_execfreq(env->exec_freq, spill_block);
 835
 836         if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
 837                 /* TODO calculate correct costs...
 838                  * (though we can't remat this node anyway so no big problem) */
 839                 spillinfo->spill_costs = env->spill_cost * spill_execfreq;
 840                 return;
 841         }
 842
 843         if(spillinfo->spills != NULL) {
 844                 spill_t *s;
 845                 double   spills_execfreq;
 846
 847                 /* calculate sum of executaion frequencies of individual spills */
 848                 spills_execfreq = 0;
 849                 s               = spillinfo->spills;
 850                 for( ; s != NULL; s = s->next) {
 851                         ir_node *spill_block = s->before;
 852                         double   freq;
 853
 854                         if(!is_Block(spill_block)) {
 855                                 spill_block = get_nodes_block(spill_block);
 856                         }
 857                         freq = get_block_execfreq(env->exec_freq, spill_block);
 858
 859                         spills_execfreq += freq;
 860                 }
 861
 862                 DB((dbg, LEVEL_1, "%+F: latespillcosts %f after def: %f\n", to_spill,
 863                     spills_execfreq * env->spill_cost,
 864                     spill_execfreq * env->spill_cost));
 865
 866                 /* multi-/latespill is advantageous -> return*/
 867                 if(spills_execfreq < spill_execfreq) {
 868                         DB((dbg, LEVEL_1, "use latespills for %+F\n", to_spill));
 869                         spillinfo->spill_costs = spills_execfreq * env->spill_cost;
 870                         return;
 871                 }
 872         }
 873
 874         /* override spillinfos or create a new one */
 875         spill         = obstack_alloc(&env->obst, sizeof(spill[0]));
 876         spill->before = skip_keeps_phis(to_spill);
 877         spill->next   = NULL;
 878         spill->spill  = NULL;
 879
 880         spillinfo->spills      = spill;
 881         spillinfo->spill_costs = spill_execfreq * env->spill_cost;
 882         DB((dbg, LEVEL_1, "spill %+F after definition\n", to_spill));
 883 }
 884
 885 void make_spill_locations_dominate_irn(spill_env_t *env, ir_node *irn)
 886 {
 887         const spill_info_t *si = get_spillinfo(env, irn);
 888         ir_node *start_block   = get_irg_start_block(get_irn_irg(irn));
 889         int n_blocks           = get_Block_dom_max_subtree_pre_num(start_block);
 890         bitset_t *reloads      = bitset_alloca(n_blocks);
 891         reloader_t *r;
 892         spill_t *s;
 893
 894         if (si == NULL)
 895                 return;
 896
 897         /* Fill the bitset with the dominance pre-order numbers
 898          * of the blocks the reloads are located in. */
 899         for (r = si->reloaders; r != NULL; r = r->next) {
 900                 ir_node *bl = get_nodes_block(r->reloader);
 901                 bitset_set(reloads, get_Block_dom_tree_pre_num(bl));
 902         }
 903
 904         /* Now, cancel out all the blocks that are dominated by each spill.
 905          * If the bitset is not empty after that, we have reloads that are
 906          * not dominated by any spill. */
 907         for (s = si->spills; s != NULL; s = s->next) {
 908                 ir_node *bl = get_nodes_block(s->before);
 909                 int start   = get_Block_dom_tree_pre_num(bl);
 910                 int end     = get_Block_dom_max_subtree_pre_num(bl);
 911
 912                 bitset_clear_range(reloads, start, end);
 913         }
 914
 915         if (!bitset_is_empty(reloads))
 916                 be_add_spill(env, si->to_spill, sched_next(si->to_spill));
 917 }
 918
 919 void be_insert_spills_reloads(spill_env_t *env)
 920 {
 921         ir_graph              *irg       = env->irg;
 922         const arch_env_t      *arch_env  = env->arch_env;
 923         const ir_exec_freq    *exec_freq = env->exec_freq;
 924         spill_info_t          *si;
 925         ir_nodeset_iterator_t  iter;
 926         ir_node               *node;
 927
 928         BE_TIMER_PUSH(t_ra_spill_apply);
 929
 930         env->new_nodes_idx = get_irg_last_idx(irg);
 931
 932         /* create all phi-ms first, this is needed so, that phis, hanging on
 933            spilled phis work correctly */
 934         foreach_ir_nodeset(&env->mem_phis, node, iter) {
 935                 spill_info_t *info = get_spillinfo(env, node);
 936                 spill_node(env, info);
 937         }
 938
 939         /* process each spilled node */
 940         for (si = set_first(env->spills); si; si = set_next(env->spills)) {
 941                 reloader_t *rld;
 942                 ir_node  *to_spill        = si->to_spill;
 943                 ir_mode  *mode            = get_irn_mode(to_spill);
 944                 ir_node **copies          = NEW_ARR_F(ir_node*, 0);
 945                 double    all_remat_costs = 0; /** costs when we would remat all nodes */
 946                 int       force_remat     = 0;
 947
 948                 DBG((dbg, LEVEL_1, "\nhandling all reloaders of %+F:\n", to_spill));
 949
 950                 determine_spill_costs(env, si);
 951
 952                 /* determine possibility of rematerialisations */
 953                 if(be_do_remats) {
 954                         /* calculate cost savings for each indivial value when it would
 955                            be rematted instead of reloaded */
 956                         for (rld = si->reloaders; rld != NULL; rld = rld->next) {
 957                                 double   freq;
 958                                 int      remat_cost;
 959                                 int      remat_cost_delta;
 960                                 ir_node *block;
 961                                 ir_node *reloader = rld->reloader;
 962
 963                                 if(rld->rematted_node != NULL) {
 964                                         DBG((dbg, LEVEL_2, "\tforced remat %+F before %+F\n",
 965                                              rld->rematted_node, reloader));
 966                                         continue;
 967                                 }
 968                                 if(rld->remat_cost_delta >= REMAT_COST_INFINITE) {
 969                                         DBG((dbg, LEVEL_2, "\treload before %+F is forbidden\n",
 970                                              reloader));
 971                                         all_remat_costs = REMAT_COST_INFINITE;
 972                                         continue;
 973                                 }
 974
 975                                 remat_cost  = check_remat_conditions_costs(env, to_spill,
 976                                                                            reloader, 0);
 977                                 if(remat_cost >= REMAT_COST_INFINITE) {
 978                                         DBG((dbg, LEVEL_2, "\tremat before %+F not possible\n",
 979                                              reloader));
 980                                         rld->remat_cost_delta = REMAT_COST_INFINITE;
 981                                         all_remat_costs       = REMAT_COST_INFINITE;
 982                                         continue;
 983                                 }
 984
 985                                 remat_cost_delta      = remat_cost - env->reload_cost;
 986                                 rld->remat_cost_delta = remat_cost_delta;
 987                                 block                 = is_Block(reloader) ? reloader : get_nodes_block(reloader);
 988                                 freq                  = get_block_execfreq(exec_freq, block);
 989                                 all_remat_costs      += remat_cost_delta * freq;
 990                                 DBG((dbg, LEVEL_2, "\tremat costs delta before %+F: "
 991                                      "%d (rel %f)\n", reloader, remat_cost_delta,
 992                                      remat_cost_delta * freq));
 993                         }
 994                         if(all_remat_costs < REMAT_COST_INFINITE) {
 995                                 /* we don't need the costs for the spill if we can remat
 996                                    all reloaders */
 997                                 all_remat_costs -= si->spill_costs;
 998
 999                                 DBG((dbg, LEVEL_2, "\tspill costs %d (rel %f)\n",
1000                                      env->spill_cost, si->spill_costs));
1001                         }
1002
1003                         if(all_remat_costs < 0) {
1004                                 DBG((dbg, LEVEL_1, "\nforcing remats of all reloaders (%f)\n",
1005                                      all_remat_costs));
1006                                 force_remat = 1;
1007                         }
1008                 }
1009
1010                 /* go through all reloads for this spill */
1011                 for (rld = si->reloaders; rld != NULL; rld = rld->next) {
1012                         ir_node *copy; /* a reload is a "copy" of the original value */
1013
1014                         if (rld->rematted_node != NULL) {
1015                                 copy = rld->rematted_node;
1016                                 sched_add_before(rld->reloader, copy);
1017                         } else if (be_do_remats &&
1018                                         (force_remat || rld->remat_cost_delta < 0)) {
1019                                 copy = do_remat(env, to_spill, rld->reloader);
1020                         } else {
1021                                 /* make sure we have a spill */
1022                                 spill_node(env, si);
1023
1024                                 /* create a reload, use the first spill for now SSA
1025                                  * reconstruction for memory comes below */
1026                                 assert(si->spills != NULL);
1027                                 copy = be_reload(arch_env, si->reload_cls, rld->reloader, mode,
1028                                                  si->spills->spill);
1029 #ifdef FIRM_STATISTICS
1030                                 env->reload_count++;
1031 #endif
1032                         }
1033
1034                         DBG((dbg, LEVEL_1, " %+F of %+F before %+F\n",
1035                              copy, to_spill, rld->reloader));
1036                         ARR_APP1(ir_node*, copies, copy);
1037                 }
1038
1039                 /* if we had any reloads or remats, then we need to reconstruct the
1040                  * SSA form for the spilled value */
1041                 if (ARR_LEN(copies) > 0) {
1042                         be_ssa_construction_env_t senv;
1043                         /* be_lv_t *lv = be_get_birg_liveness(env->birg); */
1044
1045                         be_ssa_construction_init(&senv, env->birg);
1046                         be_ssa_construction_add_copy(&senv, to_spill);
1047                         be_ssa_construction_add_copies(&senv, copies, ARR_LEN(copies));
1048                         be_ssa_construction_fix_users(&senv, to_spill);
1049
1050 #if 0
1051                         /* no need to enable this as long as we invalidate liveness
1052                            after this function... */
1053                         be_ssa_construction_update_liveness_phis(&senv);
1054                         be_liveness_update(to_spill);
1055                         len = ARR_LEN(copies);
1056                         for(i = 0; i < len; ++i) {
1057                                 be_liveness_update(lv, copies[i]);
1058                         }
1059 #endif
1060                         be_ssa_construction_destroy(&senv);
1061                 }
1062                 /* need to reconstruct SSA form if we had multiple spills */
1063                 if (si->spills != NULL && si->spills->next != NULL) {
1064                         spill_t *spill;
1065                         int      spill_count = 0;
1066
1067                         be_ssa_construction_env_t senv;
1068
1069                         be_ssa_construction_init(&senv, env->birg);
1070                         spill = si->spills;
1071                         for( ; spill != NULL; spill = spill->next) {
1072                                 /* maybe we rematerialized the value and need no spill */
1073                                 if(spill->spill == NULL)
1074                                         continue;
1075                                 be_ssa_construction_add_copy(&senv, spill->spill);
1076                                 spill_count++;
1077                         }
1078                         if(spill_count > 1) {
1079                                 /* all reloads are attached to the first spill, fix them now */
1080                                 be_ssa_construction_fix_users(&senv, si->spills->spill);
1081                         }
1082
1083                         be_ssa_construction_destroy(&senv);
1084                 }
1085
1086                 DEL_ARR_F(copies);
1087                 si->reloaders = NULL;
1088         }
1089
1090         stat_ev_dbl("spill_spills", env->spill_count);
1091         stat_ev_dbl("spill_reloads", env->reload_count);
1092         stat_ev_dbl("spill_remats", env->remat_count);
1093         stat_ev_dbl("spill_spilled_phis", env->spilled_phi_count);
1094
1095         /* Matze: In theory be_ssa_construction should take care of the liveness...
1096          * try to disable this again in the future */
1097         be_liveness_invalidate(env->birg->lv);
1098
1099         be_remove_dead_nodes_from_schedule(env->birg);
1100
1101         BE_TIMER_POP(t_ra_spill_apply);
1102 }
1103
1104 void be_init_spill(void)
1105 {
1106         FIRM_DBG_REGISTER(dbg, "firm.be.spill");
1107 }
1108
1109 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spill);