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

   1 /*
   2  * Author:      Matthias Braun
   3  * Date:                26.7.06
   4  * Copyright:   (c) Universitaet Karlsruhe
   5  * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
   6  */
   7 #ifdef HAVE_CONFIG_H
   8 #include "config.h"
   9 #endif
  10
  11 #include <stdlib.h>
  12
  13 #include "set.h"
  14
  15 #include "irgwalk.h"
  16 #include "ircons.h"
  17 #include "irprintf.h"
  18 #include "execfreq.h"
  19 #include "unionfind.h"
  20 #include "type.h"
  21 #include "irdump_t.h"
  22
  23 #include "benode_t.h"
  24 #include "besched.h"
  25 #include "bespillslots.h"
  26 #include "bechordal_t.h"
  27 #include "bejavacoal.h"
  28 #include "benodesets.h"
  29 #include "bestatevent.h"
  30 #include "bespilloptions.h"
  31 #include "bemodule.h"
  32
  33 #define DBG_COALESCING          1
  34 #define DBG_INTERFERENCES       2
  35
  36 DEBUG_ONLY(
  37 static firm_dbg_module_t *dbg = NULL;
  38 )
  39
  40 typedef struct _spill_t {
  41         ir_node *spill;
  42         /** mode of the spilled value */
  43         const ir_mode *mode;
  44         /** alignment for the spilled value */
  45         int alignment;
  46         /** index into spillslot_unionfind unionfind structure */
  47         int spillslot;
  48 } spill_t;
  49
  50 typedef struct _affinity_edge_t {
  51         double affinity;
  52         int slot1, slot2;
  53 } affinity_edge_t;
  54
  55 struct _be_fec_env_t {
  56         struct obstack obst;
  57         const arch_env_t *arch_env;
  58         be_irg_t *birg;
  59         set *spills;
  60         ir_node **reloads;
  61         affinity_edge_t **affinity_edges;
  62         set *memperms;
  63 };
  64
  65 /** Compare 2 affinity edges (used in quicksort) */
  66 static int cmp_affinity(const void *d1, const void *d2)
  67 {
  68         const affinity_edge_t * const *e1 = d1;
  69         const affinity_edge_t * const *e2 = d2;
  70
  71         // sort in descending order
  72         return (*e1)->affinity < (*e2)->affinity ? 1 : -1;
  73 }
  74
  75 static int cmp_spill(const void* d1, const void* d2, size_t size)
  76 {
  77         const spill_t* s1 = d1;
  78         const spill_t* s2 = d2;
  79         return s1->spill != s2->spill;
  80 }
  81
  82 static spill_t *get_spill(be_fec_env_t *env, ir_node *node)
  83 {
  84         spill_t spill, *res;
  85         int hash = nodeset_hash(node);
  86
  87         spill.spill = node;
  88         res = set_find(env->spills, &spill, sizeof(spill), hash);
  89
  90         return res;
  91 }
  92
  93 /*
  94  *   ____      _ _           _     ____        _ _ _
  95  *  / ___|___ | | | ___  ___| |_  / ___| _ __ (_) | |___
  96  * | |   / _ \| | |/ _ \/ __| __| \___ \| '_ \| | | / __|
  97  * | |__| (_) | | |  __/ (__| |_   ___) | |_) | | | \__ \
  98  *  \____\___/|_|_|\___|\___|\__| |____/| .__/|_|_|_|___/
  99  *                                      |_|
 100  */
 101
 102 static INLINE ir_node *get_memory_edge(const ir_node *node)
 103 {
 104         int i, arity;
 105
 106         arity = get_irn_arity(node);
 107         for(i = arity - 1; i >= 0; --i) {
 108                 ir_node *arg = get_irn_n(node, i);
 109                 if(get_irn_mode(arg) == mode_M)
 110                         return arg;
 111         }
 112
 113         return NULL;
 114 }
 115
 116 static spill_t *collect_spill(be_fec_env_t *env, ir_node *node,
 117                                       const ir_mode *mode, int align)
 118 {
 119         spill_t spill, *res;
 120         int hash = nodeset_hash(node);
 121
 122         /* insert into set of spills if not already there */
 123         spill.spill = node;
 124         res = set_find(env->spills, &spill, sizeof(spill), hash);
 125
 126         if(res == NULL) {
 127                 spill.spillslot = set_count(env->spills);
 128                 spill.mode = mode;
 129                 spill.alignment = align;
 130                 res = set_insert(env->spills, &spill, sizeof(spill), hash);
 131         } else {
 132                 assert(res->mode == mode);
 133                 assert(res->alignment == align);
 134         }
 135
 136         return res;
 137 }
 138
 139 static spill_t *collect_memphi(be_fec_env_t *env, ir_node *node,
 140                                const ir_mode *mode, int align)
 141 {
 142         int i, arity;
 143         spill_t spill, *res;
 144         int hash = nodeset_hash(node);
 145         const ir_exec_freq *exec_freq = be_get_birg_exec_freq(env->birg);
 146
 147         assert(is_Phi(node));
 148
 149         spill.spill = node;
 150         res = set_find(env->spills, &spill, sizeof(spill), hash);
 151         if(res != NULL) {
 152                 assert(res->mode == mode);
 153                 assert(res->alignment == align);
 154                 return res;
 155         }
 156
 157         spill.spillslot = set_count(env->spills);
 158         spill.mode = mode;
 159         spill.alignment = align;
 160         res = set_insert(env->spills, &spill, sizeof(spill), hash);
 161
 162         // collect attached spills and mem-phis
 163         arity = get_irn_arity(node);
 164         for(i = 0; i < arity; ++i) {
 165                 affinity_edge_t *affinty_edge;
 166                 ir_node *arg = get_irn_n(node, i);
 167                 spill_t *arg_spill;
 168
 169                 if(is_Phi(arg)) {
 170                         arg_spill = collect_memphi(env, arg, mode, align);
 171                 } else {
 172                         arg_spill = collect_spill(env, arg, mode, align);
 173                 }
 174
 175                 // add an affinity edge
 176                 affinty_edge = obstack_alloc(&env->obst, sizeof(affinty_edge[0]));
 177                 affinty_edge->affinity = get_block_execfreq(exec_freq, get_nodes_block(arg));
 178                 affinty_edge->slot1 = res->spillslot;
 179                 affinty_edge->slot2 = arg_spill->spillslot;
 180                 ARR_APP1(affinity_edge_t*, env->affinity_edges, affinty_edge);
 181         }
 182
 183         return res;
 184 }
 185
 186 void be_node_needs_frame_entity(be_fec_env_t *env, ir_node *node,
 187                                 const ir_mode *mode, int align)
 188 {
 189         ir_node *spillnode = get_memory_edge(node);
 190         spill_t *spill;
 191
 192         assert(spillnode != NULL);
 193
 194         if (is_Phi(spillnode)) {
 195                 spill = collect_memphi(env, spillnode, mode, align);
 196         } else {
 197                 spill = collect_spill(env, spillnode, mode, align);
 198         }
 199
 200         ARR_APP1(ir_node *, env->reloads, node);
 201 }
 202
 203 /*
 204  *   ____            _                      ____  _       _
 205  *  / ___|___   __ _| | ___  ___  ___ ___  / ___|| | ___ | |_ ___
 206  * | |   / _ \ / _` | |/ _ \/ __|/ __/ _ \ \___ \| |/ _ \| __/ __|
 207  * | |__| (_) | (_| | |  __/\__ \ (_|  __/  ___) | | (_) | |_\__ \
 208  *  \____\___/ \__,_|_|\___||___/\___\___| |____/|_|\___/ \__|___/
 209  */
 210
 211 static int merge_interferences(be_fec_env_t *env, bitset_t** interferences,
 212                                int* spillslot_unionfind, int s1, int s2)
 213 {
 214         int res;
 215         int i;
 216         int spillcount;
 217
 218         // merge spillslots and interferences
 219         res = uf_union(spillslot_unionfind, s1, s2);
 220         // we assume that we always merge s2 to s1 so swap s1, s2 if necessary
 221         if(res != 0) {
 222                 int t = s1;
 223                 s1 = s2;
 224                 s2 = t;
 225         }
 226
 227         bitset_or(interferences[s1], interferences[s2]);
 228
 229         // update other interferences
 230         spillcount = set_count(env->spills);
 231         for(i = 0; i < spillcount; ++i) {
 232                 bitset_t *intfs = interferences[i];
 233                 if(bitset_is_set(intfs, s2))
 234                         bitset_set(intfs, s1);
 235         }
 236
 237         return res;
 238 }
 239
 240 /**
 241  * A greedy coalescing algorithm for spillslots:
 242  *  1. Sort the list of affinity edges
 243  *  2. Try to merge slots with affinity edges (most expensive slots first)
 244  *  3. Try to merge everything else that is possible
 245  */
 246 static void do_greedy_coalescing(be_fec_env_t *env)
 247 {
 248         int spillcount;
 249         spill_t **spilllist;
 250         spill_t *spill;
 251         int i, i2;
 252         int affinity_edge_count;
 253         bitset_t **interferences;
 254         int* spillslot_unionfind;
 255         const be_lv_t *lv = be_get_birg_liveness(env->birg);
 256
 257         spillcount = set_count(env->spills);
 258         if(spillcount == 0)
 259                 return;
 260
 261         DBG((dbg, DBG_COALESCING, "Coalescing %d spillslots\n", spillcount));
 262
 263         interferences = alloca(spillcount * sizeof(interferences[0]));
 264         spillslot_unionfind = alloca(spillcount * sizeof(spillslot_unionfind[0]));
 265         spilllist = alloca(spillcount * sizeof(spilllist[0]));
 266
 267         uf_init(spillslot_unionfind, 0, spillcount);
 268
 269         DEBUG_ONLY(
 270                 memset(spilllist, 0, spillcount * sizeof(spilllist[0]));
 271         );
 272
 273         for(spill = set_first(env->spills), i = 0; spill != NULL; spill = set_next(env->spills), ++i) {
 274                 assert(spill->spillslot < spillcount);
 275                 spilllist[spill->spillslot] = spill;
 276         }
 277
 278         for(i = 0; i < spillcount; ++i) {
 279                 interferences[i] = bitset_alloca(spillcount);
 280         }
 281
 282         // construct interferences
 283         for(i = 0; i < spillcount; ++i) {
 284                 ir_node *spill1 = spilllist[i]->spill;
 285                 if(is_NoMem(spill1))
 286                         continue;
 287
 288                 for(i2 = i+1; i2 < spillcount; ++i2) {
 289                         ir_node *spill2 = spilllist[i2]->spill;
 290                         if(is_NoMem(spill2))
 291                                 continue;
 292
 293                         if(values_interfere(lv, spill1, spill2)) {
 294                                 DBG((dbg, DBG_INTERFERENCES, "Slot %d and %d interfere\n",
 295                                      i, i2));
 296                                 bitset_set(interferences[i], i2);
 297                                 bitset_set(interferences[i2], i);
 298                         }
 299                 }
 300         }
 301
 302         // sort affinity edges
 303         affinity_edge_count = ARR_LEN(env->affinity_edges);
 304         qsort(env->affinity_edges, affinity_edge_count, sizeof(env->affinity_edges[0]), cmp_affinity);
 305
 306         //dump_interference_graph(env, interferences, "before");
 307
 308         // try to merge affine nodes
 309         for(i = 0; i < affinity_edge_count; ++i) {
 310                 const affinity_edge_t *edge = env->affinity_edges[i];
 311                 int s1 = uf_find(spillslot_unionfind, edge->slot1);
 312                 int s2 = uf_find(spillslot_unionfind, edge->slot2);
 313
 314                 /* test if values interfere */
 315                 if(bitset_is_set(interferences[s1], s2)) {
 316                         assert(bitset_is_set(interferences[s2], s1));
 317                         continue;
 318                 }
 319
 320                 DBG((dbg, DBG_COALESCING, "Merging %d and %d because of affinity edge\n", s1, s2));
 321
 322                 merge_interferences(env, interferences, spillslot_unionfind, s1, s2);
 323         }
 324
 325         // try to merge as much remaining spillslots as possible
 326         for(i = 0; i < spillcount; ++i) {
 327                 int s1 = uf_find(spillslot_unionfind, i);
 328                 if(s1 != i)
 329                         continue;
 330
 331                 for(i2 = i+1; i2 < spillcount; ++i2) {
 332                         int s2 = uf_find(spillslot_unionfind, i2);
 333                         if(s2 != i2)
 334                                 continue;
 335
 336                         /* test if values interfere
 337                          * we have to test n1-n2 and n2-n1, because only 1 side gets updated
 338                          * when node merging occurs
 339                          */
 340                         if(bitset_is_set(interferences[s1], s2)) {
 341                                 assert(bitset_is_set(interferences[s2], s1));
 342                                 continue;
 343                         }
 344
 345                         DBG((dbg, DBG_COALESCING, "Merging %d and %d because it is possible\n", s1, s2));
 346
 347                         if(merge_interferences(env, interferences, spillslot_unionfind, s1, s2) != 0) {
 348                                 // we can break the loop here, because s2 is the new supernode now
 349                                 // and we'll test s2 again later anyway
 350                                 break;
 351                         }
 352                 }
 353         }
 354
 355         // assign spillslots to spills
 356         for(i = 0; i < spillcount; ++i) {
 357                 spill_t *spill = spilllist[i];
 358
 359                 spill->spillslot = uf_find(spillslot_unionfind, i);
 360         }
 361
 362         //dump_interference_graph(env, interferences, "after");
 363 }
 364
 365 /*
 366  *     _            _               _____       _   _ _   _
 367  *    / \   ___ ___(_) __ _ _ __   | ____|_ __ | |_(_) |_(_) ___  ___
 368  *   / _ \ / __/ __| |/ _` | '_ \  |  _| | '_ \| __| | __| |/ _ \/ __|
 369  *  / ___ \\__ \__ \ | (_| | | | | | |___| | | | |_| | |_| |  __/\__ \
 370  * /_/   \_\___/___/_|\__, |_| |_| |_____|_| |_|\__|_|\__|_|\___||___/
 371  *                    |___/
 372  */
 373
 374 typedef struct _spill_slot_t {
 375         int size;
 376         int align;
 377         ir_entity *entity;
 378 } spill_slot_t;
 379
 380 typedef struct _memperm_entry_t {
 381         ir_node* node;
 382         int pos;
 383         ir_entity *in;
 384         ir_entity *out;
 385         struct _memperm_entry_t *next;
 386 } memperm_entry_t;
 387
 388 typedef struct _memperm_t {
 389         ir_node *block;
 390         int entrycount;
 391         memperm_entry_t *entries;
 392 } memperm_t;
 393
 394 static int cmp_memperm(const void* d1, const void* d2, size_t size)
 395 {
 396         const memperm_t* e1 = d1;
 397         const memperm_t* e2 = d2;
 398         return e1->block != e2->block;
 399 }
 400
 401 static memperm_t *get_memperm(be_fec_env_t *env, ir_node *block)
 402 {
 403         memperm_t entry, *res;
 404         int hash;
 405
 406         entry.block = block;
 407         hash = nodeset_hash(block);
 408
 409         res = set_find(env->memperms, &entry, sizeof(entry), hash);
 410
 411         if(res == NULL) {
 412                 entry.entrycount = 0;
 413                 entry.entries = NULL;
 414                 res = set_insert(env->memperms, &entry, sizeof(entry), hash);
 415         }
 416
 417         return res;
 418 }
 419
 420 static ir_entity* create_stack_entity(be_fec_env_t *env, spill_slot_t *slot)
 421 {
 422         ir_graph *irg = be_get_birg_irg(env->birg);
 423         ir_type *frame = get_irg_frame_type(irg);
 424         ir_entity *res = frame_alloc_area(frame, slot->size, slot->align, 0);
 425
 426         // adjust size of the entity type...
 427         ir_type *enttype = get_entity_type(res);
 428         set_type_size_bytes(enttype, slot->size);
 429
 430         slot->entity = res;
 431
 432         return res;
 433 }
 434
 435 /**
 436  * Enlarges a spillslot (if necessary) so that it can carry a value of size
 437  * @p othersize and alignment @p otheralign.
 438  */
 439 static void enlarge_spillslot(spill_slot_t *slot, int otheralign, int othersize)
 440 {
 441         if(othersize > slot->size) {
 442                 slot->size = othersize;
 443         }
 444         if(otheralign > slot->align) {
 445                 if(otheralign % slot->align != 0)
 446                         slot->align *= otheralign;
 447                 else
 448                         slot->align = otheralign;
 449         } else if(slot->align % otheralign != 0) {
 450                 slot->align *= otheralign;
 451         }
 452 }
 453
 454 /**
 455  * Create stack entities for the spillslots and assign them to the spill and
 456  * reload nodes.
 457  */
 458 static void assign_spillslots(be_fec_env_t *env)
 459 {
 460         const arch_env_t *arch_env = env->arch_env;
 461         int i;
 462         int spillcount;
 463         spill_t *spill;
 464         spill_slot_t* spillslots;
 465
 466         spillcount = set_count(env->spills);
 467         spillslots = alloca(spillcount * sizeof(spillslots[0]));
 468
 469         memset(spillslots, 0, spillcount * sizeof(spillslots[0]));
 470
 471         // construct spillslots
 472         for(spill = set_first(env->spills); spill != NULL; spill = set_next(env->spills)) {
 473                 int slotid = spill->spillslot;
 474                 const ir_mode *mode = spill->mode;
 475                 spill_slot_t *slot = & (spillslots[slotid]);
 476                 int size = get_mode_size_bytes(mode);
 477                 int align = spill->alignment;
 478
 479                 if(slot->align == 0 && slot->size == 0) {
 480                         slot->align = align;
 481                         slot->size = size;
 482                 } else {
 483                         enlarge_spillslot(slot, align, size);
 484                 }
 485         }
 486
 487         for(spill = set_first(env->spills); spill != NULL; spill = set_next(env->spills)) {
 488                 spill_slot_t *slot;
 489                 ir_node *node = spill->spill;
 490                 int slotid = spill->spillslot;
 491
 492                 slot = &spillslots[slotid];
 493                 if(slot->entity == NULL) {
 494                         create_stack_entity(env, slot);
 495                 }
 496
 497                 if(is_Phi(node)) {
 498                         int i, arity;
 499                         ir_node *block = get_nodes_block(node);
 500
 501                         // should be a PhiM
 502                         assert(is_Phi(node));
 503
 504                         for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
 505                                 ir_node *arg = get_irn_n(node, i);
 506                                 ir_node *predblock = get_Block_cfgpred_block(block, i);
 507                                 spill_t *argspill;
 508                                 int argslotid;
 509
 510                                 argspill = get_spill(env, arg);
 511                                 assert(argspill != NULL);
 512
 513                                 argslotid = argspill->spillslot;
 514                                 if(slotid != argslotid) {
 515                                         memperm_t *memperm;
 516                                         memperm_entry_t *entry;
 517                                         spill_slot_t *argslot = &spillslots[argslotid];
 518                                         if(argslot->entity == NULL) {
 519                                                 create_stack_entity(env, argslot);
 520                                         }
 521
 522                                         memperm = get_memperm(env, predblock);
 523
 524                                         entry = obstack_alloc(&env->obst, sizeof(entry[0]));
 525                                         entry->node = node;
 526                                         entry->pos = i;
 527                                         entry->in = argslot->entity;
 528                                         entry->out = slot->entity;
 529                                         entry->next = memperm->entries;
 530                                         memperm->entrycount++;
 531                                         memperm->entries = entry;
 532                                 }
 533                         }
 534                 } else {
 535                         if(!is_NoMem(node))
 536                                 arch_set_frame_entity(arch_env, node, slot->entity);
 537                 }
 538         }
 539
 540         for(i = 0; i < ARR_LEN(env->reloads); ++i) {
 541                 ir_node* reload = env->reloads[i];
 542                 ir_node* spillnode = get_memory_edge(reload);
 543                 spill_t *spill = get_spill(env, spillnode);
 544                 const spill_slot_t *slot = & spillslots[spill->spillslot];
 545
 546                 assert(slot->entity != NULL);
 547
 548                 arch_set_frame_entity(arch_env, reload, slot->entity);
 549         }
 550 }
 551
 552 /**
 553  * Returns the last node in a block which is no control flow changing node
 554  */
 555 static ir_node *get_end_of_block_insertion_point(ir_node* block)
 556 {
 557         ir_node* ins = sched_last(block);
 558         while(is_Proj(ins) && get_irn_mode(ins) == mode_X) {
 559                 ins = sched_prev(ins);
 560                 assert(ins != NULL);
 561         }
 562
 563         if(is_cfop(ins)) {
 564                 while(1) {
 565                         ir_node *prev = sched_prev(ins);
 566                         if(!is_cfop(prev))
 567                                 break;
 568                         ins = prev;
 569                 }
 570         }
 571
 572         return ins;
 573 }
 574
 575 static void create_memperms(be_fec_env_t *env)
 576 {
 577         const arch_env_t *arch_env = env->arch_env;
 578         ir_graph *irg = be_get_birg_irg(env->birg);
 579         memperm_t *memperm;
 580
 581         for(memperm = set_first(env->memperms); memperm != NULL; memperm = set_next(env->memperms)) {
 582                 int i;
 583                 memperm_entry_t *entry;
 584                 ir_node *blockend;
 585                 ir_node** nodes = alloca(memperm->entrycount * sizeof(nodes[0]));
 586                 ir_node* mempermnode;
 587
 588                 assert(memperm->entrycount > 0);
 589
 590                 for(entry = memperm->entries, i = 0; entry != NULL; entry = entry->next, ++i) {
 591                         ir_node* arg = get_irn_n(entry->node, entry->pos);
 592                         nodes[i] = arg;
 593                 }
 594
 595                 mempermnode = be_new_MemPerm(arch_env, irg, memperm->block,
 596                                              memperm->entrycount, nodes);
 597
 598                 // insert node into schedule
 599                 blockend = get_end_of_block_insertion_point(memperm->block);
 600                 sched_add_before(blockend, mempermnode);
 601                 be_stat_ev("mem_perm", memperm->entrycount);
 602
 603                 i = 0;
 604                 for(entry = memperm->entries; entry != NULL; entry = entry->next, ++i) {
 605                         ir_node *proj;
 606                         ir_node* arg = get_irn_n(entry->node, entry->pos);
 607
 608                         be_set_MemPerm_in_entity(mempermnode, i, entry->in);
 609                         be_set_MemPerm_out_entity(mempermnode, i, entry->out);
 610                         set_irg_current_block(irg, memperm->block);
 611                         proj = new_Proj(mempermnode, get_irn_mode(arg), i);
 612                         sched_add_before(blockend, proj);
 613
 614                         set_irn_n(entry->node, entry->pos, proj);
 615                 }
 616         }
 617 }
 618
 619 static int count_spillslots(const be_fec_env_t *env)
 620 {
 621         const spill_t *spill;
 622         int spillcount = set_count(env->spills);
 623         bitset_t *counted = bitset_alloca(spillcount);
 624         int slotcount;
 625
 626         slotcount = 0;
 627         for(spill = set_first(env->spills); spill != NULL;
 628             spill = set_next(env->spills)) {
 629                 int spillslot = spill->spillslot;
 630                 if(!bitset_is_set(counted, spillslot)) {
 631                         slotcount++;
 632                         bitset_set(counted, spillslot);
 633                 }
 634         }
 635
 636         return slotcount;
 637 }
 638
 639 be_fec_env_t *be_new_frame_entity_coalescer(be_irg_t *birg)
 640 {
 641         const arch_env_t *arch_env = birg->main_env->arch_env;
 642
 643         be_fec_env_t *env = xmalloc(sizeof(env[0]));
 644
 645         be_assure_liveness(birg);
 646
 647         obstack_init(&env->obst);
 648         env->arch_env = arch_env;
 649         env->birg = birg;
 650         env->spills = new_set(cmp_spill, 10);
 651         env->reloads = NEW_ARR_F(ir_node*, 0);
 652         env->affinity_edges = NEW_ARR_F(affinity_edge_t*, 0);
 653         env->memperms = new_set(cmp_memperm, 10);
 654
 655         return env;
 656 }
 657
 658 void be_free_frame_entity_coalescer(be_fec_env_t *env)
 659 {
 660         del_set(env->memperms);
 661         DEL_ARR_F(env->reloads);
 662         DEL_ARR_F(env->affinity_edges);
 663         del_set(env->spills);
 664         obstack_free(&env->obst, NULL);
 665
 666         free(env);
 667 }
 668
 669 void be_assign_entities(be_fec_env_t *env)
 670 {
 671         if(be_stat_ev_is_active()) {
 672                 int count = set_count(env->spills);
 673                 be_stat_ev("spillslots", count);
 674         }
 675
 676         if(be_coalesce_spill_slots) {
 677                 do_greedy_coalescing(env);
 678         }
 679
 680         if(be_stat_ev_is_active()) {
 681                 int count = count_spillslots(env);
 682                 be_stat_ev("spillslots_after_coalescing", count);
 683         }
 684
 685         assign_spillslots(env);
 686
 687         create_memperms(env);
 688 }
 689
 690 /**
 691  * This walker function searches for reloads and collects all the spills
 692  * and memphis attached to them.
 693  */
 694 static void collect_spills_walker(ir_node *node, void *data)
 695 {
 696         be_fec_env_t *env = data;
 697         const arch_env_t *arch_env = env->arch_env;
 698         const ir_mode *mode;
 699         const arch_register_class_t *cls;
 700         int align;
 701
 702         /* classify returns classification of the irn the proj is attached to */
 703         if (is_Proj(node))
 704                 return;
 705
 706         if (!arch_irn_class_is(arch_env, node, reload))
 707                 return;
 708
 709         mode = get_irn_mode(node);
 710         cls = arch_get_irn_reg_class(arch_env, node, -1);
 711         align = arch_isa_get_reg_class_alignment(arch_env_get_isa(arch_env), cls);
 712
 713         be_node_needs_frame_entity(env, node, mode, align);
 714 }
 715
 716 void be_coalesce_spillslots(be_irg_t *birg)
 717 {
 718         be_fec_env_t *env = be_new_frame_entity_coalescer(birg);
 719
 720         /* collect reloads */
 721         irg_walk_graph(birg->irg, NULL, collect_spills_walker, env);
 722
 723         be_assign_entities(env);
 724
 725         be_free_frame_entity_coalescer(env);
 726 }
 727
 728 void be_init_spillslots(void)
 729 {
 730         FIRM_DBG_REGISTER(dbg, "firm.be.spillslots");
 731 }
 732
 733 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spillslots);