nsz Git - libfirm/blob - ir/be/bespillutil.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 #include "config.h"
  28
  29 #include <stdlib.h>
  30 #include <stdbool.h>
  31
  32 #include "pset.h"
  33 #include "irnode_t.h"
  34 #include "ircons_t.h"
  35 #include "iredges_t.h"
  36 #include "irbackedge_t.h"
  37 #include "irprintf.h"
  38 #include "ident_t.h"
  39 #include "type_t.h"
  40 #include "entity_t.h"
  41 #include "debug.h"
  42 #include "irgwalk.h"
  43 #include "array.h"
  44 #include "pdeq.h"
  45 #include "execfreq.h"
  46 #include "irnodeset.h"
  47 #include "error.h"
  48
  49 #include "bearch.h"
  50 #include "belive_t.h"
  51 #include "besched.h"
  52 #include "bespill.h"
  53 #include "bespillutil.h"
  54 #include "belive_t.h"
  55 #include "benode.h"
  56 #include "bechordal_t.h"
  57 #include "bestatevent.h"
  58 #include "bessaconstr.h"
  59 #include "beirg.h"
  60 #include "beintlive_t.h"
  61 #include "bemodule.h"
  62 #include "be_t.h"
  63
  64 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
  65
  66 #define REMAT_COST_INFINITE  1000
  67
  68 typedef struct reloader_t reloader_t;
  69 struct reloader_t {
  70         reloader_t *next;
  71         ir_node    *can_spill_after;
  72         ir_node    *reloader;
  73         ir_node    *rematted_node;
  74         int         remat_cost_delta; /** costs needed for rematerialization,
  75                                            compared to placing a reload */
  76 };
  77
  78 typedef struct spill_t spill_t;
  79 struct spill_t {
  80         spill_t *next;
  81         ir_node *after;  /**< spill has to be placed after this node (or earlier) */
  82         ir_node *spill;
  83 };
  84
  85 typedef struct spill_info_t spill_info_t;
  86 struct spill_info_t {
  87         ir_node    *to_spill;  /**< the value that should get spilled */
  88         reloader_t *reloaders; /**< list of places where the value should get
  89                                     reloaded */
  90         spill_t    *spills;    /**< list of latest places where spill must be
  91                                     placed */
  92         double      spill_costs; /**< costs needed for spilling the value */
  93         const arch_register_class_t *reload_cls; /** the register class in which the
  94                                                      reload should be placed */
  95 };
  96
  97 struct spill_env_t {
  98         const arch_env_t *arch_env;
  99         ir_graph         *irg;
 100         struct obstack    obst;
 101         be_irg_t         *birg;
 102         int               spill_cost;     /**< the cost of a single spill node */
 103         int               reload_cost;    /**< the cost of a reload node */
 104         set              *spills;         /**< all spill_info_t's, which must be
 105                                                placed */
 106         ir_nodeset_t      mem_phis;       /**< set of all spilled phis. */
 107         ir_exec_freq     *exec_freq;
 108
 109 #ifdef FIRM_STATISTICS
 110         unsigned          spill_count;
 111         unsigned          reload_count;
 112         unsigned          remat_count;
 113         unsigned          spilled_phi_count;
 114 #endif
 115 };
 116
 117 /**
 118  * Compare two spill infos.
 119  */
 120 static int cmp_spillinfo(const void *x, const void *y, size_t size)
 121 {
 122         const spill_info_t *xx = x;
 123         const spill_info_t *yy = y;
 124         (void) size;
 125
 126         return xx->to_spill != yy->to_spill;
 127 }
 128
 129 /**
 130  * Returns spill info for a specific value (the value that is to be spilled)
 131  */
 132 static spill_info_t *get_spillinfo(const spill_env_t *env, ir_node *value)
 133 {
 134         spill_info_t info, *res;
 135         int hash = hash_irn(value);
 136
 137         info.to_spill = value;
 138         res = set_find(env->spills, &info, sizeof(info), hash);
 139
 140         if (res == NULL) {
 141                 info.reloaders   = NULL;
 142                 info.spills      = NULL;
 143                 info.spill_costs = -1;
 144                 info.reload_cls  = NULL;
 145                 res = set_insert(env->spills, &info, sizeof(info), hash);
 146         }
 147
 148         return res;
 149 }
 150
 151 spill_env_t *be_new_spill_env(be_irg_t *birg)
 152 {
 153         const arch_env_t *arch_env = birg->main_env->arch_env;
 154
 155         spill_env_t *env = XMALLOC(spill_env_t);
 156         env->spills                     = new_set(cmp_spillinfo, 1024);
 157         env->irg            = be_get_birg_irg(birg);
 158         env->birg           = birg;
 159         env->arch_env       = arch_env;
 160         ir_nodeset_init(&env->mem_phis);
 161         env->spill_cost     = arch_env->spill_cost;
 162         env->reload_cost    = arch_env->reload_cost;
 163         env->exec_freq      = be_get_birg_exec_freq(birg);
 164         obstack_init(&env->obst);
 165
 166 #ifdef FIRM_STATISTICS
 167         env->spill_count       = 0;
 168         env->reload_count      = 0;
 169         env->remat_count       = 0;
 170         env->spilled_phi_count = 0;
 171 #endif
 172
 173         return env;
 174 }
 175
 176 void be_delete_spill_env(spill_env_t *env)
 177 {
 178         del_set(env->spills);
 179         ir_nodeset_destroy(&env->mem_phis);
 180         obstack_free(&env->obst, NULL);
 181         free(env);
 182 }
 183
 184 /*
 185  *  ____  _                  ____      _                 _
 186  * |  _ \| | __ _  ___ ___  |  _ \ ___| | ___   __ _  __| |___
 187  * | |_) | |/ _` |/ __/ _ \ | |_) / _ \ |/ _ \ / _` |/ _` / __|
 188  * |  __/| | (_| | (_|  __/ |  _ <  __/ | (_) | (_| | (_| \__ \
 189  * |_|   |_|\__,_|\___\___| |_| \_\___|_|\___/ \__,_|\__,_|___/
 190  *
 191  */
 192
 193 void be_add_spill(spill_env_t *env, ir_node *to_spill, ir_node *after)
 194 {
 195         spill_info_t  *spill_info = get_spillinfo(env, to_spill);
 196         const ir_node *insn       = skip_Proj_const(to_spill);
 197         spill_t       *spill;
 198         spill_t       *s;
 199         spill_t       *last;
 200
 201         assert(!arch_irn_is(insn, dont_spill));
 202         DB((dbg, LEVEL_1, "Add spill of %+F after %+F\n", to_spill, after));
 203
 204         /* Just for safety make sure that we do not insert the spill in front of a phi */
 205         assert(!is_Phi(sched_next(after)));
 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->after, after)) {
 213                         DB((dbg, LEVEL_1, "...dominated by %+F, not added\n", s->after));
 214                         return;
 215                 }
 216                 /* remove spills that we dominate */
 217                 if (value_dominates(after, s->after)) {
 218                         DB((dbg, LEVEL_1, "...remove old spill at %+F\n", s->after));
 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         = OALLOC(&env->obst, spill_t);
 230         spill->after  = after;
 231         spill->next   = spill_info->spills;
 232         spill->spill  = NULL;
 233
 234         spill_info->spills = spill;
 235 }
 236
 237 void be_add_remat(spill_env_t *env, ir_node *to_spill, ir_node *before,
 238                   ir_node *rematted_node)
 239 {
 240         spill_info_t *spill_info;
 241         reloader_t *reloader;
 242
 243         spill_info = get_spillinfo(env, to_spill);
 244
 245         /* add the remat information */
 246         reloader                   = OALLOC(&env->obst, reloader_t);
 247         reloader->next             = spill_info->reloaders;
 248         reloader->reloader         = before;
 249         reloader->rematted_node    = rematted_node;
 250         reloader->remat_cost_delta = 0; /* We will never have a cost win over a
 251                                            reload since we're not even allowed to
 252                                            create a reload */
 253
 254         spill_info->reloaders  = reloader;
 255
 256         DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be rematerialized before %+F\n",
 257                 to_spill, before));
 258 }
 259
 260 void be_add_reload2(spill_env_t *env, ir_node *to_spill, ir_node *before,
 261                 ir_node *can_spill_after, const arch_register_class_t *reload_cls,
 262                 int allow_remat)
 263 {
 264         spill_info_t  *info;
 265         reloader_t    *rel;
 266         const ir_node *insn = skip_Proj_const(to_spill);
 267
 268         assert(!arch_irn_is(insn, dont_spill));
 269
 270         info = get_spillinfo(env, to_spill);
 271
 272         if (is_Phi(to_spill)) {
 273                 int i, arity;
 274
 275                 /* create spillinfos for the phi arguments */
 276                 for (i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
 277                         ir_node *arg = get_irn_n(to_spill, i);
 278                         get_spillinfo(env, arg);
 279                 }
 280         }
 281
 282         assert(!is_Proj(before) && !be_is_Keep(before));
 283
 284         /* put reload into list */
 285         rel                   = OALLOC(&env->obst, reloader_t);
 286         rel->next             = info->reloaders;
 287         rel->reloader         = before;
 288         rel->rematted_node    = NULL;
 289         rel->can_spill_after  = can_spill_after;
 290         rel->remat_cost_delta = allow_remat ? 0 : REMAT_COST_INFINITE;
 291
 292         info->reloaders  = rel;
 293         assert(info->reload_cls == NULL || info->reload_cls == reload_cls);
 294         info->reload_cls = reload_cls;
 295
 296         DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be reloaded before %+F, may%s be rematerialized\n",
 297                 to_spill, before, allow_remat ? "" : " not"));
 298 }
 299
 300 void be_add_reload(spill_env_t *senv, ir_node *to_spill, ir_node *before,
 301                    const arch_register_class_t *reload_cls, int allow_remat)
 302 {
 303         be_add_reload2(senv, to_spill, before, to_spill, reload_cls, allow_remat);
 304
 305 }
 306
 307 ir_node *be_get_end_of_block_insertion_point(const ir_node *block)
 308 {
 309         ir_node *last = sched_last(block);
 310
 311         /* we might have keeps behind the jump... */
 312         while (be_is_Keep(last)) {
 313                 last = sched_prev(last);
 314                 assert(!sched_is_end(last));
 315         }
 316
 317         assert(is_cfop(last));
 318
 319         /* add the reload before the (cond-)jump */
 320         return last;
 321 }
 322
 323 static ir_node *skip_keeps_phis(ir_node *node)
 324 {
 325         while (true) {
 326                 ir_node *next = sched_next(node);
 327                 if (!is_Phi(next) && !be_is_Keep(next) && !be_is_CopyKeep(next))
 328                         break;
 329                 node = next;
 330         }
 331         return node;
 332 }
 333
 334 /**
 335  * Returns the point at which you can insert a node that should be executed
 336  * before block @p block when coming from pred @p pos.
 337  */
 338 static ir_node *get_block_insertion_point(ir_node *block, int pos)
 339 {
 340         ir_node *predblock;
 341
 342         /* simply add the reload to the beginning of the block if we only have 1
 343          * predecessor. We don't need to check for phis as there can't be any in a
 344          * block with only 1 pred. */
 345         if (get_Block_n_cfgpreds(block) == 1) {
 346                 assert(!is_Phi(sched_first(block)));
 347                 return sched_first(block);
 348         }
 349
 350         /* We have to reload the value in pred-block */
 351         predblock = get_Block_cfgpred_block(block, pos);
 352         return be_get_end_of_block_insertion_point(predblock);
 353 }
 354
 355 void be_add_reload_at_end(spill_env_t *env, ir_node *to_spill,
 356                           const ir_node *block,
 357                           const arch_register_class_t *reload_cls,
 358                           int allow_remat)
 359 {
 360         ir_node *before = be_get_end_of_block_insertion_point(block);
 361         be_add_reload(env, to_spill, before, reload_cls, allow_remat);
 362 }
 363
 364 void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block,
 365                            int pos,     const arch_register_class_t *reload_cls,
 366                            int allow_remat)
 367 {
 368         ir_node *before = get_block_insertion_point(block, pos);
 369         be_add_reload(env, to_spill, before, reload_cls, allow_remat);
 370 }
 371
 372 void be_spill_phi(spill_env_t *env, ir_node *node)
 373 {
 374         ir_node *block;
 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         for (i = 0, arity = get_irn_arity(node); i < arity; ++i) {
 384                 ir_node *arg = get_irn_n(node, i);
 385                 ir_node *insert;
 386
 387                 /* some backends have virtual noreg/unknown nodes that are not scheduled
 388                  * and simply always available. */
 389                 if (!sched_is_scheduled(arg)) {
 390                         ir_node *pred_block = get_Block_cfgpred_block(block, i);
 391                         insert = be_get_end_of_block_insertion_point(pred_block);
 392                         insert = sched_prev(insert);
 393                 } else {
 394                         insert = skip_keeps_phis(arg);
 395                 }
 396
 397                 be_add_spill(env, arg, insert);
 398         }
 399 }
 400
 401 /*
 402  *   ____                _         ____        _ _ _
 403  *  / ___|_ __ ___  __ _| |_ ___  / ___| _ __ (_) | |___
 404  * | |   | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
 405  * | |___| | |  __/ (_| | ||  __/  ___) | |_) | | | \__ \
 406  *  \____|_|  \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
 407  *                                      |_|
 408  */
 409
 410 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo);
 411
 412 /**
 413  * Creates a spill.
 414  *
 415  * @param senv      the spill environment
 416  * @param irn       the node that should be spilled
 417  * @param ctx_irn   an user of the spilled node
 418  *
 419  * @return a be_Spill node
 420  */
 421 static void spill_irn(spill_env_t *env, spill_info_t *spillinfo)
 422 {
 423         ir_node       *to_spill = spillinfo->to_spill;
 424         const ir_node *insn     = skip_Proj_const(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(insn)) {
 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 ... \n", to_spill));
 440         spill = spillinfo->spills;
 441         for ( ; spill != NULL; spill = spill->next) {
 442                 ir_node *after = spill->after;
 443                 ir_node *block = get_block(after);
 444
 445                 after = skip_keeps_phis(after);
 446
 447                 spill->spill = be_spill(block, to_spill);
 448                 sched_add_after(skip_Proj(after), spill->spill);
 449                 DB((dbg, LEVEL_1, "\t%+F after %+F\n", spill->spill, after));
 450 #ifdef FIRM_STATISTICS
 451                 env->spill_count++;
 452 #endif
 453         }
 454         DBG((dbg, LEVEL_1, "\n"));
 455 }
 456
 457 static void spill_node(spill_env_t *env, spill_info_t *spillinfo);
 458
 459 /**
 460  * If the first usage of a Phi result would be out of memory
 461  * there is no sense in allocating a register for it.
 462  * Thus we spill it and all its operands to the same spill slot.
 463  * Therefore the phi/dataB becomes a phi/Memory
 464  *
 465  * @param senv      the spill environment
 466  * @param phi       the Phi node that should be spilled
 467  * @param ctx_irn   an user of the spilled node
 468  */
 469 static void spill_phi(spill_env_t *env, spill_info_t *spillinfo)
 470 {
 471         ir_graph *irg   = env->irg;
 472         ir_node  *phi   = spillinfo->to_spill;
 473         ir_node  *block = get_nodes_block(phi);
 474         ir_node  *unknown;
 475         ir_node **ins;
 476         spill_t  *spill;
 477         int       i;
 478         int       arity;
 479
 480         assert(is_Phi(phi));
 481         assert(!get_opt_cse());
 482         DBG((dbg, LEVEL_1, "spilling Phi %+F:\n", phi));
 483
 484         /* build a new PhiM */
 485         arity   = get_irn_arity(phi);
 486         ins     = ALLOCAN(ir_node*, arity);
 487         unknown = new_r_Unknown(irg, mode_M);
 488         for (i = 0; i < arity; ++i) {
 489                 ins[i] = unknown;
 490         }
 491
 492         /* override or replace spills list... */
 493         spill         = OALLOC(&env->obst, spill_t);
 494         spill->after  = skip_keeps_phis(phi);
 495         spill->spill  = new_r_Phi(block, arity, ins, mode_M);
 496         spill->next   = NULL;
 497
 498         spillinfo->spills = spill;
 499 #ifdef FIRM_STATISTICS
 500         env->spilled_phi_count++;
 501 #endif
 502
 503         for (i = 0; i < arity; ++i) {
 504                 ir_node      *arg      = get_irn_n(phi, i);
 505                 spill_info_t *arg_info = get_spillinfo(env, arg);
 506
 507                 determine_spill_costs(env, arg_info);
 508                 spill_node(env, arg_info);
 509
 510                 set_irn_n(spill->spill, i, arg_info->spills->spill);
 511         }
 512         DBG((dbg, LEVEL_1, "... done spilling Phi %+F, created PhiM %+F\n", phi,
 513              spill->spill));
 514 }
 515
 516 /**
 517  * Spill a node.
 518  *
 519  * @param senv      the spill environment
 520  * @param to_spill  the node that should be spilled
 521  */
 522 static void spill_node(spill_env_t *env, spill_info_t *spillinfo)
 523 {
 524         ir_node *to_spill;
 525
 526         /* node is already spilled */
 527         if (spillinfo->spills != NULL && spillinfo->spills->spill != NULL)
 528                 return;
 529
 530         to_spill = spillinfo->to_spill;
 531
 532         if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
 533                 spill_phi(env, spillinfo);
 534         } else {
 535                 spill_irn(env, spillinfo);
 536         }
 537 }
 538
 539 /*
 540  *
 541  *  ____                      _            _       _ _
 542  * |  _ \ ___ _ __ ___   __ _| |_ ___ _ __(_) __ _| (_)_______
 543  * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_  / _ \
 544  * |  _ <  __/ | | | | | (_| | ||  __/ |  | | (_| | | |/ /  __/
 545  * |_| \_\___|_| |_| |_|\__,_|\__\___|_|  |_|\__,_|_|_/___\___|
 546  *
 547  */
 548
 549 /**
 550  * Tests whether value @p arg is available before node @p reloader
 551  * @returns 1 if value is available, 0 otherwise
 552  */
 553 static int is_value_available(spill_env_t *env, const ir_node *arg,
 554                               const ir_node *reloader)
 555 {
 556         if (is_Unknown(arg) || arg == new_NoMem())
 557                 return 1;
 558
 559         if (be_is_Spill(skip_Proj_const(arg)))
 560                 return 1;
 561
 562         if (arg == get_irg_frame(env->irg))
 563                 return 1;
 564
 565         (void)reloader;
 566
 567         /*
 568          * Ignore registers are always available
 569          */
 570         if (arch_irn_is_ignore(arg))
 571                 return 1;
 572
 573         return 0;
 574 }
 575
 576 /**
 577  * Check if a node is rematerializable. This tests for the following conditions:
 578  *
 579  * - The node itself is rematerializable
 580  * - All arguments of the node are available or also rematerialisable
 581  * - The costs for the rematerialisation operation is less or equal a limit
 582  *
 583  * Returns the costs needed for rematerialisation or something
 584  * >= REMAT_COST_INFINITE if remat is not possible.
 585  */
 586 static int check_remat_conditions_costs(spill_env_t *env,
 587                 const ir_node *spilled, const ir_node *reloader, int parentcosts)
 588 {
 589         int i, arity;
 590         int argremats;
 591         int costs = 0;
 592         const ir_node *insn = skip_Proj_const(spilled);
 593
 594         assert(!be_is_Spill(insn));
 595         if (!arch_irn_is(insn, rematerializable))
 596                 return REMAT_COST_INFINITE;
 597
 598         if (be_is_Reload(insn)) {
 599                 costs += 2;
 600         } else {
 601                 costs += arch_get_op_estimated_cost(insn);
 602         }
 603         if (parentcosts + costs >= env->reload_cost + env->spill_cost) {
 604                 return REMAT_COST_INFINITE;
 605         }
 606         /* never rematerialize a node which modifies the flags.
 607          * (would be better to test wether the flags are actually live at point
 608          * reloader...)
 609          */
 610         if (arch_irn_is(insn, modify_flags)) {
 611                 return REMAT_COST_INFINITE;
 612         }
 613
 614         argremats = 0;
 615         for (i = 0, arity = get_irn_arity(insn); i < arity; ++i) {
 616                 ir_node *arg = get_irn_n(insn, i);
 617
 618                 if (is_value_available(env, arg, reloader))
 619                         continue;
 620
 621                 /* we have to rematerialize the argument as well */
 622                 ++argremats;
 623                 if (argremats > 1) {
 624                         /* we only support rematerializing 1 argument at the moment,
 625                          * as multiple arguments could increase register pressure */
 626                         return REMAT_COST_INFINITE;
 627                 }
 628
 629                 costs += check_remat_conditions_costs(env, arg, reloader,
 630                                                       parentcosts + costs);
 631                 if (parentcosts + costs >= env->reload_cost + env->spill_cost)
 632                         return REMAT_COST_INFINITE;
 633         }
 634
 635         return costs;
 636 }
 637
 638 /**
 639  * Re-materialize a node.
 640  *
 641  * @param senv      the spill environment
 642  * @param spilled   the node that was spilled
 643  * @param reloader  a irn that requires a reload
 644  */
 645 static ir_node *do_remat(spill_env_t *env, ir_node *spilled, ir_node *reloader)
 646 {
 647         int i, arity;
 648         ir_node *res;
 649         ir_node *bl;
 650         ir_node **ins;
 651
 652         if (is_Block(reloader)) {
 653                 bl = reloader;
 654         } else {
 655                 bl = get_nodes_block(reloader);
 656         }
 657
 658         ins = ALLOCAN(ir_node*, get_irn_arity(spilled));
 659         for (i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
 660                 ir_node *arg = get_irn_n(spilled, i);
 661
 662                 if (is_value_available(env, arg, reloader)) {
 663                         ins[i] = arg;
 664                 } else {
 665                         ins[i] = do_remat(env, arg, reloader);
 666 #ifdef FIRM_STATISTICS
 667                         /* don't count the recursive call as remat */
 668                         env->remat_count--;
 669 #endif
 670                 }
 671         }
 672
 673         /* create a copy of the node */
 674         res = new_ir_node(get_irn_dbg_info(spilled), env->irg, bl,
 675                           get_irn_op(spilled), get_irn_mode(spilled),
 676                           get_irn_arity(spilled), ins);
 677         copy_node_attr(env->irg, spilled, res);
 678         arch_env_mark_remat(env->arch_env, res);
 679
 680         DBG((dbg, LEVEL_1, "Insert remat %+F of %+F before reloader %+F\n", res, spilled, reloader));
 681
 682         if (! is_Proj(res)) {
 683                 /* insert in schedule */
 684                 sched_reset(res);
 685                 sched_add_before(reloader, res);
 686 #ifdef FIRM_STATISTICS
 687                 env->remat_count++;
 688 #endif
 689         }
 690
 691         return res;
 692 }
 693
 694 double be_get_spill_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
 695 {
 696         ir_node *block = get_nodes_block(before);
 697         double   freq  = get_block_execfreq(env->exec_freq, block);
 698         (void) to_spill;
 699
 700         return env->spill_cost * freq;
 701 }
 702
 703 unsigned be_get_reload_costs_no_weight(spill_env_t *env, const ir_node *to_spill,
 704                                        const ir_node *before)
 705 {
 706         if (be_do_remats) {
 707                 /* is the node rematerializable? */
 708                 unsigned costs = check_remat_conditions_costs(env, to_spill, before, 0);
 709                 if (costs < (unsigned) env->reload_cost)
 710                         return costs;
 711         }
 712
 713         return env->reload_cost;
 714 }
 715
 716 double be_get_reload_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
 717 {
 718         ir_node      *block = get_nodes_block(before);
 719         double        freq  = get_block_execfreq(env->exec_freq, block);
 720
 721         if (be_do_remats) {
 722                 /* is the node rematerializable? */
 723                 int costs = check_remat_conditions_costs(env, to_spill, before, 0);
 724                 if (costs < env->reload_cost)
 725                         return costs * freq;
 726         }
 727
 728         return env->reload_cost * freq;
 729 }
 730
 731 int be_is_rematerializable(spill_env_t *env, const ir_node *to_remat,
 732                            const ir_node *before)
 733 {
 734         return check_remat_conditions_costs(env, to_remat, before, 0) < REMAT_COST_INFINITE;
 735 }
 736
 737 double be_get_reload_costs_on_edge(spill_env_t *env, ir_node *to_spill,
 738                                    ir_node *block, int pos)
 739 {
 740         ir_node *before = get_block_insertion_point(block, pos);
 741         return be_get_reload_costs(env, to_spill, before);
 742 }
 743
 744 /*
 745  *  ___                     _     ____      _                 _
 746  * |_ _|_ __  ___  ___ _ __| |_  |  _ \ ___| | ___   __ _  __| |___
 747  *  | || '_ \/ __|/ _ \ '__| __| | |_) / _ \ |/ _ \ / _` |/ _` / __|
 748  *  | || | | \__ \  __/ |  | |_  |  _ <  __/ | (_) | (_| | (_| \__ \
 749  * |___|_| |_|___/\___|_|   \__| |_| \_\___|_|\___/ \__,_|\__,_|___/
 750  *
 751  */
 752
 753 /**
 754  * analyzes how to best spill a node and determine costs for that
 755  */
 756 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo)
 757 {
 758         ir_node       *to_spill = spillinfo->to_spill;
 759         const ir_node *insn     = skip_Proj_const(to_spill);
 760         ir_node       *spill_block;
 761         spill_t       *spill;
 762         double         spill_execfreq;
 763
 764         /* already calculated? */
 765         if (spillinfo->spill_costs >= 0)
 766                 return;
 767
 768         assert(!arch_irn_is(insn, dont_spill));
 769         assert(!be_is_Reload(insn));
 770
 771         /* some backends have virtual noreg/unknown nodes that are not scheduled
 772          * and simply always available.
 773          * TODO: this is kinda hairy, the NoMem is correct for an Unknown as Phi
 774          * predecessor (of a PhiM) but this test might match other things too...
 775          */
 776         if (!sched_is_scheduled(insn)) {
 777                 /* override spillinfos or create a new one */
 778                 spill_t *spill = OALLOC(&env->obst, spill_t);
 779                 spill->after = NULL;
 780                 spill->next  = NULL;
 781                 spill->spill = new_NoMem();
 782
 783                 spillinfo->spills      = spill;
 784                 spillinfo->spill_costs = 0;
 785
 786                 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
 787                 return;
 788         }
 789
 790         spill_block    = get_nodes_block(insn);
 791         spill_execfreq = get_block_execfreq(env->exec_freq, spill_block);
 792
 793         if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
 794                 /* TODO calculate correct costs...
 795                  * (though we can't remat this node anyway so no big problem) */
 796                 spillinfo->spill_costs = env->spill_cost * spill_execfreq;
 797                 return;
 798         }
 799
 800         if (spillinfo->spills != NULL) {
 801                 spill_t *s;
 802                 double   spills_execfreq;
 803
 804                 /* calculate sum of execution frequencies of individual spills */
 805                 spills_execfreq = 0;
 806                 s               = spillinfo->spills;
 807                 for ( ; s != NULL; s = s->next) {
 808                         ir_node *spill_block = get_block(s->after);
 809                         double   freq = get_block_execfreq(env->exec_freq, spill_block);
 810
 811                         spills_execfreq += freq;
 812                 }
 813
 814                 DB((dbg, LEVEL_1, "%+F: latespillcosts %f after def: %f\n", to_spill,
 815                     spills_execfreq * env->spill_cost,
 816                     spill_execfreq * env->spill_cost));
 817
 818                 /* multi-/latespill is advantageous -> return*/
 819                 if (spills_execfreq < spill_execfreq) {
 820                         DB((dbg, LEVEL_1, "use latespills for %+F\n", to_spill));
 821                         spillinfo->spill_costs = spills_execfreq * env->spill_cost;
 822                         return;
 823                 }
 824         }
 825
 826         /* override spillinfos or create a new one */
 827         spill        = OALLOC(&env->obst, spill_t);
 828         spill->after = skip_keeps_phis(to_spill);
 829         spill->next  = NULL;
 830         spill->spill = NULL;
 831
 832         spillinfo->spills      = spill;
 833         spillinfo->spill_costs = spill_execfreq * env->spill_cost;
 834         DB((dbg, LEVEL_1, "spill %+F after definition\n", to_spill));
 835 }
 836
 837 void make_spill_locations_dominate_irn(spill_env_t *env, ir_node *irn)
 838 {
 839         const spill_info_t *si = get_spillinfo(env, irn);
 840         ir_node *start_block   = get_irg_start_block(get_irn_irg(irn));
 841         int n_blocks           = get_Block_dom_max_subtree_pre_num(start_block);
 842         bitset_t *reloads      = bitset_alloca(n_blocks);
 843         reloader_t *r;
 844         spill_t *s;
 845
 846         if (si == NULL)
 847                 return;
 848
 849         /* Fill the bitset with the dominance pre-order numbers
 850          * of the blocks the reloads are located in. */
 851         for (r = si->reloaders; r != NULL; r = r->next) {
 852                 ir_node *bl = get_nodes_block(r->reloader);
 853                 bitset_set(reloads, get_Block_dom_tree_pre_num(bl));
 854         }
 855
 856         /* Now, cancel out all the blocks that are dominated by each spill.
 857          * If the bitset is not empty after that, we have reloads that are
 858          * not dominated by any spill. */
 859         for (s = si->spills; s != NULL; s = s->next) {
 860                 ir_node *bl = get_nodes_block(s->after);
 861                 int start   = get_Block_dom_tree_pre_num(bl);
 862                 int end     = get_Block_dom_max_subtree_pre_num(bl);
 863
 864                 bitset_clear_range(reloads, start, end);
 865         }
 866
 867         if (!bitset_is_empty(reloads))
 868                 be_add_spill(env, si->to_spill, si->to_spill);
 869 }
 870
 871 void be_insert_spills_reloads(spill_env_t *env)
 872 {
 873         const ir_exec_freq    *exec_freq = env->exec_freq;
 874         spill_info_t          *si;
 875         ir_nodeset_iterator_t  iter;
 876         ir_node               *node;
 877
 878         be_timer_push(T_RA_SPILL_APPLY);
 879
 880         /* create all phi-ms first, this is needed so, that phis, hanging on
 881            spilled phis work correctly */
 882         foreach_ir_nodeset(&env->mem_phis, node, iter) {
 883                 spill_info_t *info = get_spillinfo(env, node);
 884                 spill_node(env, info);
 885         }
 886
 887         /* process each spilled node */
 888         for (si = set_first(env->spills); si; si = set_next(env->spills)) {
 889                 reloader_t *rld;
 890                 ir_node  *to_spill        = si->to_spill;
 891                 ir_mode  *mode            = get_irn_mode(to_spill);
 892                 ir_node **copies          = NEW_ARR_F(ir_node*, 0);
 893                 double    all_remat_costs = 0; /** costs when we would remat all nodes */
 894                 int       force_remat     = 0;
 895
 896                 DBG((dbg, LEVEL_1, "\nhandling all reloaders of %+F:\n", to_spill));
 897
 898                 determine_spill_costs(env, si);
 899
 900                 /* determine possibility of rematerialisations */
 901                 if (be_do_remats) {
 902                         /* calculate cost savings for each indivial value when it would
 903                            be rematted instead of reloaded */
 904                         for (rld = si->reloaders; rld != NULL; rld = rld->next) {
 905                                 double   freq;
 906                                 int      remat_cost;
 907                                 int      remat_cost_delta;
 908                                 ir_node *block;
 909                                 ir_node *reloader = rld->reloader;
 910
 911                                 if (rld->rematted_node != NULL) {
 912                                         DBG((dbg, LEVEL_2, "\tforced remat %+F before %+F\n",
 913                                              rld->rematted_node, reloader));
 914                                         continue;
 915                                 }
 916                                 if (rld->remat_cost_delta >= REMAT_COST_INFINITE) {
 917                                         DBG((dbg, LEVEL_2, "\treload before %+F is forbidden\n",
 918                                              reloader));
 919                                         all_remat_costs = REMAT_COST_INFINITE;
 920                                         continue;
 921                                 }
 922
 923                                 remat_cost  = check_remat_conditions_costs(env, to_spill,
 924                                                                            reloader, 0);
 925                                 if (remat_cost >= REMAT_COST_INFINITE) {
 926                                         DBG((dbg, LEVEL_2, "\tremat before %+F not possible\n",
 927                                              reloader));
 928                                         rld->remat_cost_delta = REMAT_COST_INFINITE;
 929                                         all_remat_costs       = REMAT_COST_INFINITE;
 930                                         continue;
 931                                 }
 932
 933                                 remat_cost_delta      = remat_cost - env->reload_cost;
 934                                 rld->remat_cost_delta = remat_cost_delta;
 935                                 block                 = is_Block(reloader) ? reloader : get_nodes_block(reloader);
 936                                 freq                  = get_block_execfreq(exec_freq, block);
 937                                 all_remat_costs      += remat_cost_delta * freq;
 938                                 DBG((dbg, LEVEL_2, "\tremat costs delta before %+F: "
 939                                      "%d (rel %f)\n", reloader, remat_cost_delta,
 940                                      remat_cost_delta * freq));
 941                         }
 942                         if (all_remat_costs < REMAT_COST_INFINITE) {
 943                                 /* we don't need the costs for the spill if we can remat
 944                                    all reloaders */
 945                                 all_remat_costs -= si->spill_costs;
 946
 947                                 DBG((dbg, LEVEL_2, "\tspill costs %d (rel %f)\n",
 948                                      env->spill_cost, si->spill_costs));
 949                         }
 950
 951                         if (all_remat_costs < 0) {
 952                                 DBG((dbg, LEVEL_1, "\nforcing remats of all reloaders (%f)\n",
 953                                      all_remat_costs));
 954                                 force_remat = 1;
 955                         }
 956                 }
 957
 958                 /* go through all reloads for this spill */
 959                 for (rld = si->reloaders; rld != NULL; rld = rld->next) {
 960                         ir_node *copy; /* a reload is a "copy" of the original value */
 961
 962                         if (rld->rematted_node != NULL) {
 963                                 copy = rld->rematted_node;
 964                                 sched_add_before(rld->reloader, copy);
 965                         } else if (be_do_remats &&
 966                                         (force_remat || rld->remat_cost_delta < 0)) {
 967                                 copy = do_remat(env, to_spill, rld->reloader);
 968                         } else {
 969                                 /* make sure we have a spill */
 970                                 spill_node(env, si);
 971
 972                                 /* create a reload, use the first spill for now SSA
 973                                  * reconstruction for memory comes below */
 974                                 assert(si->spills != NULL);
 975                                 copy = be_reload(si->reload_cls, rld->reloader, mode,
 976                                                  si->spills->spill);
 977 #ifdef FIRM_STATISTICS
 978                                 env->reload_count++;
 979 #endif
 980                         }
 981
 982                         DBG((dbg, LEVEL_1, " %+F of %+F before %+F\n",
 983                              copy, to_spill, rld->reloader));
 984                         ARR_APP1(ir_node*, copies, copy);
 985                 }
 986
 987                 /* if we had any reloads or remats, then we need to reconstruct the
 988                  * SSA form for the spilled value */
 989                 if (ARR_LEN(copies) > 0) {
 990                         be_ssa_construction_env_t senv;
 991                         /* be_lv_t *lv = be_get_birg_liveness(env->birg); */
 992
 993                         be_ssa_construction_init(&senv, env->birg);
 994                         be_ssa_construction_add_copy(&senv, to_spill);
 995                         be_ssa_construction_add_copies(&senv, copies, ARR_LEN(copies));
 996                         be_ssa_construction_fix_users(&senv, to_spill);
 997
 998 #if 0
 999                         /* no need to enable this as long as we invalidate liveness
1000                            after this function... */
1001                         be_ssa_construction_update_liveness_phis(&senv);
1002                         be_liveness_update(to_spill);
1003                         len = ARR_LEN(copies);
1004                         for (i = 0; i < len; ++i) {
1005                                 be_liveness_update(lv, copies[i]);
1006                         }
1007 #endif
1008                         be_ssa_construction_destroy(&senv);
1009                 }
1010                 /* need to reconstruct SSA form if we had multiple spills */
1011                 if (si->spills != NULL && si->spills->next != NULL) {
1012                         spill_t *spill;
1013                         int      spill_count = 0;
1014
1015                         be_ssa_construction_env_t senv;
1016
1017                         be_ssa_construction_init(&senv, env->birg);
1018                         spill = si->spills;
1019                         for ( ; spill != NULL; spill = spill->next) {
1020                                 /* maybe we rematerialized the value and need no spill */
1021                                 if (spill->spill == NULL)
1022                                         continue;
1023                                 be_ssa_construction_add_copy(&senv, spill->spill);
1024                                 spill_count++;
1025                         }
1026                         if (spill_count > 1) {
1027                                 /* all reloads are attached to the first spill, fix them now */
1028                                 be_ssa_construction_fix_users(&senv, si->spills->spill);
1029                         }
1030
1031                         be_ssa_construction_destroy(&senv);
1032                 }
1033
1034                 DEL_ARR_F(copies);
1035                 si->reloaders = NULL;
1036         }
1037
1038         stat_ev_dbl("spill_spills", env->spill_count);
1039         stat_ev_dbl("spill_reloads", env->reload_count);
1040         stat_ev_dbl("spill_remats", env->remat_count);
1041         stat_ev_dbl("spill_spilled_phis", env->spilled_phi_count);
1042
1043         /* Matze: In theory be_ssa_construction should take care of the liveness...
1044          * try to disable this again in the future */
1045         be_liveness_invalidate(env->birg->lv);
1046
1047         be_remove_dead_nodes_from_schedule(env->birg);
1048
1049         be_timer_pop(T_RA_SPILL_APPLY);
1050 }
1051
1052 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spill);
1053 void be_init_spill(void)
1054 {
1055         FIRM_DBG_REGISTER(dbg, "firm.be.spill");
1056 }