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