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         int               spill_cost;     /**< the cost of a single spill node */
 102         int               reload_cost;    /**< the cost of a reload node */
 103         set              *spills;         /**< all spill_info_t's, which must be
 104                                                placed */
 105         ir_nodeset_t      mem_phis;       /**< set of all spilled phis. */
 106         ir_exec_freq     *exec_freq;
 107
 108 #ifdef FIRM_STATISTICS
 109         unsigned          spill_count;
 110         unsigned          reload_count;
 111         unsigned          remat_count;
 112         unsigned          spilled_phi_count;
 113 #endif
 114 };
 115
 116 /**
 117  * Compare two spill infos.
 118  */
 119 static int cmp_spillinfo(const void *x, const void *y, size_t size)
 120 {
 121         const spill_info_t *xx = (const spill_info_t*)x;
 122         const spill_info_t *yy = (const spill_info_t*)y;
 123         (void) size;
 124
 125         return xx->to_spill != yy->to_spill;
 126 }
 127
 128 /**
 129  * Returns spill info for a specific value (the value that is to be spilled)
 130  */
 131 static spill_info_t *get_spillinfo(const spill_env_t *env, ir_node *value)
 132 {
 133         spill_info_t info, *res;
 134         int hash = hash_irn(value);
 135
 136         info.to_spill = value;
 137         res = (spill_info_t*)set_find(env->spills, &info, sizeof(info), hash);
 138
 139         if (res == NULL) {
 140                 info.reloaders   = NULL;
 141                 info.spills      = NULL;
 142                 info.spill_costs = -1;
 143                 info.reload_cls  = NULL;
 144                 res = (spill_info_t*)set_insert(env->spills, &info, sizeof(info), hash);
 145         }
 146
 147         return res;
 148 }
 149
 150 spill_env_t *be_new_spill_env(ir_graph *irg)
 151 {
 152         const arch_env_t *arch_env = be_get_irg_arch_env(irg);
 153
 154         spill_env_t *env = XMALLOC(spill_env_t);
 155         env->spills         = new_set(cmp_spillinfo, 1024);
 156         env->irg            = irg;
 157         env->arch_env       = arch_env;
 158         ir_nodeset_init(&env->mem_phis);
 159         env->spill_cost     = arch_env->spill_cost;
 160         env->reload_cost    = arch_env->reload_cost;
 161         env->exec_freq      = be_get_irg_exec_freq(irg);
 162         obstack_init(&env->obst);
 163
 164 #ifdef FIRM_STATISTICS
 165         env->spill_count       = 0;
 166         env->reload_count      = 0;
 167         env->remat_count       = 0;
 168         env->spilled_phi_count = 0;
 169 #endif
 170
 171         return env;
 172 }
 173
 174 void be_delete_spill_env(spill_env_t *env)
 175 {
 176         del_set(env->spills);
 177         ir_nodeset_destroy(&env->mem_phis);
 178         obstack_free(&env->obst, NULL);
 179         free(env);
 180 }
 181
 182 /*
 183  *  ____  _                  ____      _                 _
 184  * |  _ \| | __ _  ___ ___  |  _ \ ___| | ___   __ _  __| |___
 185  * | |_) | |/ _` |/ __/ _ \ | |_) / _ \ |/ _ \ / _` |/ _` / __|
 186  * |  __/| | (_| | (_|  __/ |  _ <  __/ | (_) | (_| | (_| \__ \
 187  * |_|   |_|\__,_|\___\___| |_| \_\___|_|\___/ \__,_|\__,_|___/
 188  *
 189  */
 190
 191 void be_add_spill(spill_env_t *env, ir_node *to_spill, ir_node *after)
 192 {
 193         spill_info_t  *spill_info = get_spillinfo(env, to_spill);
 194         spill_t       *spill;
 195         spill_t       *s;
 196         spill_t       *last;
 197
 198         assert(!arch_irn_is(skip_Proj_const(to_spill), dont_spill));
 199         DB((dbg, LEVEL_1, "Add spill of %+F after %+F\n", to_spill, after));
 200
 201         /* Just for safety make sure that we do not insert the spill in front of a phi */
 202         assert(!is_Phi(sched_next(after)));
 203
 204         /* spills that are dominated by others are not needed */
 205         last = NULL;
 206         s    = spill_info->spills;
 207         for ( ; s != NULL; s = s->next) {
 208                 /* no need to add this spill if it is dominated by another */
 209                 if (value_dominates(s->after, after)) {
 210                         DB((dbg, LEVEL_1, "...dominated by %+F, not added\n", s->after));
 211                         return;
 212                 }
 213                 /* remove spills that we dominate */
 214                 if (value_dominates(after, s->after)) {
 215                         DB((dbg, LEVEL_1, "...remove old spill at %+F\n", s->after));
 216                         if (last != NULL) {
 217                                 last->next         = s->next;
 218                         } else {
 219                                 spill_info->spills = s->next;
 220                         }
 221                 } else {
 222                         last = s;
 223                 }
 224         }
 225
 226         spill         = OALLOC(&env->obst, spill_t);
 227         spill->after  = after;
 228         spill->next   = spill_info->spills;
 229         spill->spill  = NULL;
 230
 231         spill_info->spills = spill;
 232 }
 233
 234 void be_add_remat(spill_env_t *env, ir_node *to_spill, ir_node *before,
 235                   ir_node *rematted_node)
 236 {
 237         spill_info_t *spill_info;
 238         reloader_t *reloader;
 239
 240         spill_info = get_spillinfo(env, to_spill);
 241
 242         /* add the remat information */
 243         reloader                   = OALLOC(&env->obst, reloader_t);
 244         reloader->next             = spill_info->reloaders;
 245         reloader->reloader         = before;
 246         reloader->rematted_node    = rematted_node;
 247         reloader->remat_cost_delta = 0; /* We will never have a cost win over a
 248                                            reload since we're not even allowed to
 249                                            create a reload */
 250
 251         spill_info->reloaders  = reloader;
 252
 253         DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be rematerialized before %+F\n",
 254                 to_spill, before));
 255 }
 256
 257 void be_add_reload2(spill_env_t *env, ir_node *to_spill, ir_node *before,
 258                 ir_node *can_spill_after, const arch_register_class_t *reload_cls,
 259                 int allow_remat)
 260 {
 261         spill_info_t  *info;
 262         reloader_t    *rel;
 263
 264         assert(!arch_irn_is(skip_Proj_const(to_spill), dont_spill));
 265
 266         info = get_spillinfo(env, to_spill);
 267
 268         if (is_Phi(to_spill)) {
 269                 int i, arity;
 270
 271                 /* create spillinfos for the phi arguments */
 272                 for (i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
 273                         ir_node *arg = get_irn_n(to_spill, i);
 274                         get_spillinfo(env, arg);
 275                 }
 276         }
 277
 278         assert(!is_Proj(before) && !be_is_Keep(before));
 279
 280         /* put reload into list */
 281         rel                   = OALLOC(&env->obst, reloader_t);
 282         rel->next             = info->reloaders;
 283         rel->reloader         = before;
 284         rel->rematted_node    = NULL;
 285         rel->can_spill_after  = can_spill_after;
 286         rel->remat_cost_delta = allow_remat ? 0 : REMAT_COST_INFINITE;
 287
 288         info->reloaders  = rel;
 289         assert(info->reload_cls == NULL || info->reload_cls == reload_cls);
 290         info->reload_cls = reload_cls;
 291
 292         DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be reloaded before %+F, may%s be rematerialized\n",
 293                 to_spill, before, allow_remat ? "" : " not"));
 294 }
 295
 296 void be_add_reload(spill_env_t *senv, ir_node *to_spill, ir_node *before,
 297                    const arch_register_class_t *reload_cls, int allow_remat)
 298 {
 299         be_add_reload2(senv, to_spill, before, to_spill, reload_cls, allow_remat);
 300
 301 }
 302
 303 ir_node *be_get_end_of_block_insertion_point(const ir_node *block)
 304 {
 305         ir_node *last = sched_last(block);
 306
 307         /* we might have keeps behind the jump... */
 308         while (be_is_Keep(last)) {
 309                 last = sched_prev(last);
 310                 assert(!sched_is_end(last));
 311         }
 312
 313         assert(is_cfop(last));
 314
 315         /* add the reload before the (cond-)jump */
 316         return last;
 317 }
 318
 319 static ir_node *skip_keeps_phis(ir_node *node)
 320 {
 321         while (true) {
 322                 ir_node *next = sched_next(node);
 323                 if (!is_Phi(next) && !be_is_Keep(next) && !be_is_CopyKeep(next))
 324                         break;
 325                 node = next;
 326         }
 327         return node;
 328 }
 329
 330 /**
 331  * Returns the point at which you can insert a node that should be executed
 332  * before block @p block when coming from pred @p pos.
 333  */
 334 static ir_node *get_block_insertion_point(ir_node *block, int pos)
 335 {
 336         ir_node *predblock;
 337
 338         /* simply add the reload to the beginning of the block if we only have 1
 339          * predecessor. We don't need to check for phis as there can't be any in a
 340          * block with only 1 pred. */
 341         if (get_Block_n_cfgpreds(block) == 1) {
 342                 assert(!is_Phi(sched_first(block)));
 343                 return sched_first(block);
 344         }
 345
 346         /* We have to reload the value in pred-block */
 347         predblock = get_Block_cfgpred_block(block, pos);
 348         return be_get_end_of_block_insertion_point(predblock);
 349 }
 350
 351 void be_add_reload_at_end(spill_env_t *env, ir_node *to_spill,
 352                           const ir_node *block,
 353                           const arch_register_class_t *reload_cls,
 354                           int allow_remat)
 355 {
 356         ir_node *before = be_get_end_of_block_insertion_point(block);
 357         be_add_reload(env, to_spill, before, reload_cls, allow_remat);
 358 }
 359
 360 void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block,
 361                            int pos, const arch_register_class_t *reload_cls,
 362                            int allow_remat)
 363 {
 364         ir_node *before = get_block_insertion_point(block, pos);
 365         be_add_reload(env, to_spill, before, reload_cls, allow_remat);
 366 }
 367
 368 void be_spill_phi(spill_env_t *env, ir_node *node)
 369 {
 370         ir_node *block;
 371         int i, arity;
 372
 373         assert(is_Phi(node));
 374
 375         ir_nodeset_insert(&env->mem_phis, node);
 376
 377         /* create spills for the phi arguments */
 378         block = get_nodes_block(node);
 379         for (i = 0, arity = get_irn_arity(node); i < arity; ++i) {
 380                 ir_node *arg = get_irn_n(node, i);
 381                 ir_node *insert;
 382
 383                 /* some backends have virtual noreg/unknown nodes that are not scheduled
 384                  * and simply always available. */
 385                 if (!sched_is_scheduled(arg)) {
 386                         ir_node *pred_block = get_Block_cfgpred_block(block, i);
 387                         insert = be_get_end_of_block_insertion_point(pred_block);
 388                         insert = sched_prev(insert);
 389                 } else {
 390                         insert = skip_keeps_phis(arg);
 391                 }
 392
 393                 be_add_spill(env, arg, insert);
 394         }
 395 }
 396
 397 /*
 398  *   ____                _         ____        _ _ _
 399  *  / ___|_ __ ___  __ _| |_ ___  / ___| _ __ (_) | |___
 400  * | |   | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
 401  * | |___| | |  __/ (_| | ||  __/  ___) | |_) | | | \__ \
 402  *  \____|_|  \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
 403  *                                      |_|
 404  */
 405
 406 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo);
 407
 408 /**
 409  * Creates a spill.
 410  *
 411  * @param senv      the spill environment
 412  * @param irn       the node that should be spilled
 413  * @param ctx_irn   an user of the spilled node
 414  *
 415  * @return a be_Spill node
 416  */
 417 static void spill_irn(spill_env_t *env, spill_info_t *spillinfo)
 418 {
 419         ir_node       *to_spill = spillinfo->to_spill;
 420         const ir_node *insn     = skip_Proj_const(to_spill);
 421         spill_t *spill;
 422
 423         /* determine_spill_costs must have been run before */
 424         assert(spillinfo->spill_costs >= 0);
 425
 426         /* some backends have virtual noreg/unknown nodes that are not scheduled
 427          * and simply always available. */
 428         if (!sched_is_scheduled(insn)) {
 429                 /* override spillinfos or create a new one */
 430                 ir_graph *irg = get_irn_irg(to_spill);
 431                 spillinfo->spills->spill = new_r_NoMem(irg);
 432                 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
 433                 return;
 434         }
 435
 436         DBG((dbg, LEVEL_1, "spilling %+F ... \n", to_spill));
 437         spill = spillinfo->spills;
 438         for ( ; spill != NULL; spill = spill->next) {
 439                 ir_node *after = spill->after;
 440                 ir_node *block = get_block(after);
 441
 442                 after = skip_keeps_phis(after);
 443
 444                 spill->spill = be_spill(block, to_spill);
 445                 sched_add_after(skip_Proj(after), spill->spill);
 446                 DB((dbg, LEVEL_1, "\t%+F after %+F\n", spill->spill, after));
 447 #ifdef FIRM_STATISTICS
 448                 env->spill_count++;
 449 #endif
 450         }
 451         DBG((dbg, LEVEL_1, "\n"));
 452 }
 453
 454 static void spill_node(spill_env_t *env, spill_info_t *spillinfo);
 455
 456 /**
 457  * If the first usage of a Phi result would be out of memory
 458  * there is no sense in allocating a register for it.
 459  * Thus we spill it and all its operands to the same spill slot.
 460  * Therefore the phi/dataB becomes a phi/Memory
 461  *
 462  * @param senv      the spill environment
 463  * @param phi       the Phi node that should be spilled
 464  * @param ctx_irn   an user of the spilled node
 465  */
 466 static void spill_phi(spill_env_t *env, spill_info_t *spillinfo)
 467 {
 468         ir_graph *irg   = env->irg;
 469         ir_node  *phi   = spillinfo->to_spill;
 470         ir_node  *block = get_nodes_block(phi);
 471         ir_node  *unknown;
 472         ir_node **ins;
 473         spill_t  *spill;
 474         int       i;
 475         int       arity;
 476
 477         assert(is_Phi(phi));
 478         assert(!get_opt_cse());
 479         DBG((dbg, LEVEL_1, "spilling Phi %+F:\n", phi));
 480
 481         /* build a new PhiM */
 482         arity   = get_irn_arity(phi);
 483         ins     = ALLOCAN(ir_node*, arity);
 484         unknown = new_r_Unknown(irg, mode_M);
 485         for (i = 0; i < arity; ++i) {
 486                 ins[i] = unknown;
 487         }
 488
 489         /* override or replace spills list... */
 490         spill         = OALLOC(&env->obst, spill_t);
 491         spill->after  = skip_keeps_phis(phi);
 492         spill->spill  = new_r_Phi(block, arity, ins, mode_M);
 493         spill->next   = NULL;
 494
 495         spillinfo->spills = spill;
 496 #ifdef FIRM_STATISTICS
 497         env->spilled_phi_count++;
 498 #endif
 499
 500         for (i = 0; i < arity; ++i) {
 501                 ir_node      *arg      = get_irn_n(phi, i);
 502                 spill_info_t *arg_info = get_spillinfo(env, arg);
 503
 504                 determine_spill_costs(env, arg_info);
 505                 spill_node(env, arg_info);
 506
 507                 set_irn_n(spill->spill, i, arg_info->spills->spill);
 508         }
 509         DBG((dbg, LEVEL_1, "... done spilling Phi %+F, created PhiM %+F\n", phi,
 510              spill->spill));
 511 }
 512
 513 /**
 514  * Spill a node.
 515  *
 516  * @param senv      the spill environment
 517  * @param to_spill  the node that should be spilled
 518  */
 519 static void spill_node(spill_env_t *env, spill_info_t *spillinfo)
 520 {
 521         ir_node *to_spill;
 522
 523         /* node is already spilled */
 524         if (spillinfo->spills != NULL && spillinfo->spills->spill != NULL)
 525                 return;
 526
 527         to_spill = spillinfo->to_spill;
 528
 529         if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
 530                 spill_phi(env, spillinfo);
 531         } else {
 532                 spill_irn(env, spillinfo);
 533         }
 534 }
 535
 536 /*
 537  *
 538  *  ____                      _            _       _ _
 539  * |  _ \ ___ _ __ ___   __ _| |_ ___ _ __(_) __ _| (_)_______
 540  * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_  / _ \
 541  * |  _ <  __/ | | | | | (_| | ||  __/ |  | | (_| | | |/ /  __/
 542  * |_| \_\___|_| |_| |_|\__,_|\__\___|_|  |_|\__,_|_|_/___\___|
 543  *
 544  */
 545
 546 /**
 547  * Tests whether value @p arg is available before node @p reloader
 548  * @returns 1 if value is available, 0 otherwise
 549  */
 550 static int is_value_available(spill_env_t *env, const ir_node *arg,
 551                               const ir_node *reloader)
 552 {
 553         if (is_Unknown(arg) || is_NoMem(arg))
 554                 return 1;
 555
 556         if (be_is_Spill(skip_Proj_const(arg)))
 557                 return 1;
 558
 559         if (arg == get_irg_frame(env->irg))
 560                 return 1;
 561
 562         (void)reloader;
 563
 564         if (get_irn_mode(arg) == mode_T)
 565                 return 0;
 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                 ir_graph *irg = get_irn_irg(to_spill);
 778                 /* override spillinfos or create a new one */
 779                 spill_t *spill = OALLOC(&env->obst, spill_t);
 780                 spill->after = NULL;
 781                 spill->next  = NULL;
 782                 spill->spill = new_r_NoMem(irg);
 783
 784                 spillinfo->spills      = spill;
 785                 spillinfo->spill_costs = 0;
 786
 787                 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
 788                 return;
 789         }
 790
 791         spill_block    = get_nodes_block(insn);
 792         spill_execfreq = get_block_execfreq(env->exec_freq, spill_block);
 793
 794         if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
 795                 /* TODO calculate correct costs...
 796                  * (though we can't remat this node anyway so no big problem) */
 797                 spillinfo->spill_costs = env->spill_cost * spill_execfreq;
 798                 return;
 799         }
 800
 801         if (spillinfo->spills != NULL) {
 802                 spill_t *s;
 803                 double   spills_execfreq;
 804
 805                 /* calculate sum of execution frequencies of individual spills */
 806                 spills_execfreq = 0;
 807                 s               = spillinfo->spills;
 808                 for ( ; s != NULL; s = s->next) {
 809                         ir_node *spill_block = get_block(s->after);
 810                         double   freq = get_block_execfreq(env->exec_freq, spill_block);
 811
 812                         spills_execfreq += freq;
 813                 }
 814
 815                 DB((dbg, LEVEL_1, "%+F: latespillcosts %f after def: %f\n", to_spill,
 816                     spills_execfreq * env->spill_cost,
 817                     spill_execfreq * env->spill_cost));
 818
 819                 /* multi-/latespill is advantageous -> return*/
 820                 if (spills_execfreq < spill_execfreq) {
 821                         DB((dbg, LEVEL_1, "use latespills for %+F\n", to_spill));
 822                         spillinfo->spill_costs = spills_execfreq * env->spill_cost;
 823                         return;
 824                 }
 825         }
 826
 827         /* override spillinfos or create a new one */
 828         spill        = OALLOC(&env->obst, spill_t);
 829         spill->after = skip_keeps_phis(to_spill);
 830         spill->next  = NULL;
 831         spill->spill = NULL;
 832
 833         spillinfo->spills      = spill;
 834         spillinfo->spill_costs = spill_execfreq * env->spill_cost;
 835         DB((dbg, LEVEL_1, "spill %+F after definition\n", to_spill));
 836 }
 837
 838 void make_spill_locations_dominate_irn(spill_env_t *env, ir_node *irn)
 839 {
 840         const spill_info_t *si = get_spillinfo(env, irn);
 841         ir_node *start_block   = get_irg_start_block(get_irn_irg(irn));
 842         int n_blocks           = get_Block_dom_max_subtree_pre_num(start_block);
 843         bitset_t *reloads      = bitset_alloca(n_blocks);
 844         reloader_t *r;
 845         spill_t *s;
 846
 847         if (si == NULL)
 848                 return;
 849
 850         /* Fill the bitset with the dominance pre-order numbers
 851          * of the blocks the reloads are located in. */
 852         for (r = si->reloaders; r != NULL; r = r->next) {
 853                 ir_node *bl = get_nodes_block(r->reloader);
 854                 bitset_set(reloads, get_Block_dom_tree_pre_num(bl));
 855         }
 856
 857         /* Now, cancel out all the blocks that are dominated by each spill.
 858          * If the bitset is not empty after that, we have reloads that are
 859          * not dominated by any spill. */
 860         for (s = si->spills; s != NULL; s = s->next) {
 861                 ir_node *bl = get_nodes_block(s->after);
 862                 int start   = get_Block_dom_tree_pre_num(bl);
 863                 int end     = get_Block_dom_max_subtree_pre_num(bl);
 864
 865                 bitset_clear_range(reloads, start, end);
 866         }
 867
 868         if (!bitset_is_empty(reloads))
 869                 be_add_spill(env, si->to_spill, si->to_spill);
 870 }
 871
 872 void be_insert_spills_reloads(spill_env_t *env)
 873 {
 874         const ir_exec_freq    *exec_freq = env->exec_freq;
 875         spill_info_t          *si;
 876         ir_nodeset_iterator_t  iter;
 877         ir_node               *node;
 878
 879         be_timer_push(T_RA_SPILL_APPLY);
 880
 881         /* create all phi-ms first, this is needed so, that phis, hanging on
 882            spilled phis work correctly */
 883         foreach_ir_nodeset(&env->mem_phis, node, iter) {
 884                 spill_info_t *info = get_spillinfo(env, node);
 885                 spill_node(env, info);
 886         }
 887
 888         /* process each spilled node */
 889         foreach_set(env->spills, spill_info_t*, si) {
 890                 reloader_t *rld;
 891                 ir_node  *to_spill        = si->to_spill;
 892                 ir_mode  *mode            = get_irn_mode(to_spill);
 893                 ir_node **copies          = NEW_ARR_F(ir_node*, 0);
 894                 double    all_remat_costs = 0; /** costs when we would remat all nodes */
 895                 int       force_remat     = 0;
 896
 897                 DBG((dbg, LEVEL_1, "\nhandling all reloaders of %+F:\n", to_spill));
 898
 899                 determine_spill_costs(env, si);
 900
 901                 /* determine possibility of rematerialisations */
 902                 if (be_do_remats) {
 903                         /* calculate cost savings for each indivial value when it would
 904                            be rematted instead of reloaded */
 905                         for (rld = si->reloaders; rld != NULL; rld = rld->next) {
 906                                 double   freq;
 907                                 int      remat_cost;
 908                                 int      remat_cost_delta;
 909                                 ir_node *block;
 910                                 ir_node *reloader = rld->reloader;
 911
 912                                 if (rld->rematted_node != NULL) {
 913                                         DBG((dbg, LEVEL_2, "\tforced remat %+F before %+F\n",
 914                                              rld->rematted_node, reloader));
 915                                         continue;
 916                                 }
 917                                 if (rld->remat_cost_delta >= REMAT_COST_INFINITE) {
 918                                         DBG((dbg, LEVEL_2, "\treload before %+F is forbidden\n",
 919                                              reloader));
 920                                         all_remat_costs = REMAT_COST_INFINITE;
 921                                         continue;
 922                                 }
 923
 924                                 remat_cost  = check_remat_conditions_costs(env, to_spill,
 925                                                                            reloader, 0);
 926                                 if (remat_cost >= REMAT_COST_INFINITE) {
 927                                         DBG((dbg, LEVEL_2, "\tremat before %+F not possible\n",
 928                                              reloader));
 929                                         rld->remat_cost_delta = REMAT_COST_INFINITE;
 930                                         all_remat_costs       = REMAT_COST_INFINITE;
 931                                         continue;
 932                                 }
 933
 934                                 remat_cost_delta      = remat_cost - env->reload_cost;
 935                                 rld->remat_cost_delta = remat_cost_delta;
 936                                 block                 = is_Block(reloader) ? reloader : get_nodes_block(reloader);
 937                                 freq                  = get_block_execfreq(exec_freq, block);
 938                                 all_remat_costs      += remat_cost_delta * freq;
 939                                 DBG((dbg, LEVEL_2, "\tremat costs delta before %+F: "
 940                                      "%d (rel %f)\n", reloader, remat_cost_delta,
 941                                      remat_cost_delta * freq));
 942                         }
 943                         if (all_remat_costs < REMAT_COST_INFINITE) {
 944                                 /* we don't need the costs for the spill if we can remat
 945                                    all reloaders */
 946                                 all_remat_costs -= si->spill_costs;
 947
 948                                 DBG((dbg, LEVEL_2, "\tspill costs %d (rel %f)\n",
 949                                      env->spill_cost, si->spill_costs));
 950                         }
 951
 952                         if (all_remat_costs < 0) {
 953                                 DBG((dbg, LEVEL_1, "\nforcing remats of all reloaders (%f)\n",
 954                                      all_remat_costs));
 955                                 force_remat = 1;
 956                         }
 957                 }
 958
 959                 /* go through all reloads for this spill */
 960                 for (rld = si->reloaders; rld != NULL; rld = rld->next) {
 961                         ir_node *copy; /* a reload is a "copy" of the original value */
 962
 963                         if (rld->rematted_node != NULL) {
 964                                 copy = rld->rematted_node;
 965                                 sched_add_before(rld->reloader, copy);
 966                         } else if (be_do_remats &&
 967                                         (force_remat || rld->remat_cost_delta < 0)) {
 968                                 copy = do_remat(env, to_spill, rld->reloader);
 969                         } else {
 970                                 /* make sure we have a spill */
 971                                 spill_node(env, si);
 972
 973                                 /* create a reload, use the first spill for now SSA
 974                                  * reconstruction for memory comes below */
 975                                 assert(si->spills != NULL);
 976                                 copy = be_reload(si->reload_cls, rld->reloader, mode,
 977                                                  si->spills->spill);
 978 #ifdef FIRM_STATISTICS
 979                                 env->reload_count++;
 980 #endif
 981                         }
 982
 983                         DBG((dbg, LEVEL_1, " %+F of %+F before %+F\n",
 984                              copy, to_spill, rld->reloader));
 985                         ARR_APP1(ir_node*, copies, copy);
 986                 }
 987
 988                 /* if we had any reloads or remats, then we need to reconstruct the
 989                  * SSA form for the spilled value */
 990                 if (ARR_LEN(copies) > 0) {
 991                         be_ssa_construction_env_t senv;
 992                         /* be_lv_t *lv = be_get_irg_liveness(env->irg); */
 993
 994                         be_ssa_construction_init(&senv, env->irg);
 995                         be_ssa_construction_add_copy(&senv, to_spill);
 996                         be_ssa_construction_add_copies(&senv, copies, ARR_LEN(copies));
 997                         be_ssa_construction_fix_users(&senv, to_spill);
 998
 999 #if 0
1000                         /* no need to enable this as long as we invalidate liveness
1001                            after this function... */
1002                         be_ssa_construction_update_liveness_phis(&senv);
1003                         be_liveness_update(to_spill);
1004                         len = ARR_LEN(copies);
1005                         for (i = 0; i < len; ++i) {
1006                                 be_liveness_update(lv, copies[i]);
1007                         }
1008 #endif
1009                         be_ssa_construction_destroy(&senv);
1010                 }
1011                 /* need to reconstruct SSA form if we had multiple spills */
1012                 if (si->spills != NULL && si->spills->next != NULL) {
1013                         spill_t *spill;
1014                         int      spill_count = 0;
1015
1016                         be_ssa_construction_env_t senv;
1017
1018                         be_ssa_construction_init(&senv, env->irg);
1019                         spill = si->spills;
1020                         for ( ; spill != NULL; spill = spill->next) {
1021                                 /* maybe we rematerialized the value and need no spill */
1022                                 if (spill->spill == NULL)
1023                                         continue;
1024                                 be_ssa_construction_add_copy(&senv, spill->spill);
1025                                 spill_count++;
1026                         }
1027                         if (spill_count > 1) {
1028                                 /* all reloads are attached to the first spill, fix them now */
1029                                 be_ssa_construction_fix_users(&senv, si->spills->spill);
1030                         }
1031
1032                         be_ssa_construction_destroy(&senv);
1033                 }
1034
1035                 DEL_ARR_F(copies);
1036                 si->reloaders = NULL;
1037         }
1038
1039         stat_ev_dbl("spill_spills", env->spill_count);
1040         stat_ev_dbl("spill_reloads", env->reload_count);
1041         stat_ev_dbl("spill_remats", env->remat_count);
1042         stat_ev_dbl("spill_spilled_phis", env->spilled_phi_count);
1043
1044         /* Matze: In theory be_ssa_construction should take care of the liveness...
1045          * try to disable this again in the future */
1046         be_liveness_invalidate(be_get_irg_liveness(env->irg));
1047
1048         be_remove_dead_nodes_from_schedule(env->irg);
1049
1050         be_timer_pop(T_RA_SPILL_APPLY);
1051 }
1052
1053 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spill);
1054 void be_init_spill(void)
1055 {
1056         FIRM_DBG_REGISTER(dbg, "firm.be.spill");
1057 }