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

   1 /**
   2  * Implements a list scheduler for the MRIS algorithm in:
   3  * Govindarajan, Yang, Amaral, Zhang, Gao
   4  * Minimum Register Instruction Sequencing to Reduce Register Spills
   5  * in out-of-order issue superscalar architectures
   6  * @author Sebastian Hack
   7  * @date   04.04.2006
   8  */
   9 #ifdef HAVE_CONFIG_H
  10 #include "config.h"
  11 #endif
  12
  13 #include <limits.h>
  14
  15 #include "obst.h"
  16 #include "debug.h"
  17
  18 #include "irgraph_t.h"
  19 #include "irnode_t.h"
  20 #include "iredges_t.h"
  21 #include "ircons_t.h"
  22 #include "irphase_t.h"
  23 #include "irdump_t.h"
  24 #include "irgwalk.h"
  25 #include "irtools.h"
  26 #include "irbitset.h"
  27
  28 #include "height.h"
  29
  30 #include "benode_t.h"
  31 #include "besched_t.h"
  32 #include "beschedmris.h"
  33
  34 struct _mris_env_t {
  35         phase_t            ph;
  36         heights_t         *heights;
  37         const arch_env_t  *aenv;
  38         ir_graph          *irg;
  39         ir_node           *bl;
  40         int               visited;
  41         struct list_head  lineage_head;
  42         struct obstack    obst;
  43         DEBUG_ONLY(firm_dbg_module_t *dbg;)
  44 };
  45
  46 typedef struct _mris_irn_t {
  47         int visited;
  48         ir_node *lineage_start;
  49         ir_node *lineage_next;
  50         ir_node *lineage_end;
  51         struct list_head lineage_list;
  52 } mris_irn_t;
  53
  54 #define to_appear(env, irn) (to_appear_in_schedule(irn) && get_nodes_block(irn) == env->bl)
  55
  56 #define get_mris_irn(env, irn)   ((mris_irn_t *) phase_get_or_set_irn_data(&env->ph, irn))
  57 #define foreach_lineage(env, pos, tmp) list_for_each_entry_safe(mris_irn_t, pos, tmp, &(env)->lineage_head, lineage_list)
  58
  59 static void *mris_irn_data_init(phase_t *ph, ir_node *irn, void *data)
  60 {
  61         mris_irn_t *mi = data ? data : phase_alloc(ph, sizeof(mi[0]));
  62         memset(mi, 0, sizeof(mi[0]));
  63         INIT_LIST_HEAD(&mi->lineage_list);
  64         return mi;
  65 }
  66
  67 #if 0
  68 static int compute_height(mris_env_t *env, ir_node *irn, unsigned long visited)
  69 {
  70         mris_irn_t *mi = get_mris_irn(env, irn);
  71
  72         if(get_irn_visited(irn) >= visited) {
  73                 DBG((env->dbg, LEVEL_3, "\theight of %+F = %d\n", irn, mi->height));
  74                 return mi->height;
  75         }
  76
  77         else {
  78                 const ir_edge_t *edge;
  79
  80                 set_irn_visited(irn, visited);
  81                 mi->height  = 0;
  82
  83                 foreach_out_edge(irn, edge) {
  84                         ir_node *dep = get_edge_src_irn(edge);
  85
  86                         if(!is_Block(dep) && get_nodes_block(dep) == env->bl) {
  87                                 int dep_height = compute_height(env, dep, visited);
  88                                 mi->height     = MAX(mi->height, dep_height);
  89                         }
  90                 }
  91
  92                 mi->height++;
  93                 DBG((env->dbg, LEVEL_3, "\tsetting height of %+F = %d\n", irn, mi->height));
  94         }
  95
  96         return mi->height;
  97 }
  98
  99 static void compute_heights(mris_env_t *env)
 100 {
 101         const ir_edge_t *edge;
 102         unsigned long visited;
 103
 104         visited = get_irg_visited(env->irg) + 1;
 105         set_irg_visited(env->irg, visited);
 106
 107         foreach_out_edge(env->bl, edge) {
 108                 ir_node *dep = get_edge_src_irn(edge);
 109                 if(to_appear(env, dep))
 110                         compute_height(env, dep, visited);
 111         }
 112 }
 113 #endif
 114
 115 #define valid_node(env, dep) (to_appear(env, dep) && !be_is_Keep(dep))
 116
 117 static void grow_all_descendands(mris_env_t *env, ir_node *irn, bitset_t *visited)
 118 {
 119         const ir_edge_t *edge;
 120
 121         // assert(get_irn_mode(irn) != mode_T);
 122
 123         foreach_out_edge(irn, edge) {
 124                 ir_node *desc = get_edge_src_irn(edge);
 125                 if(valid_node(env, desc) && !bitset_contains_irn(visited, desc)) {
 126                         obstack_ptr_grow(&env->obst, desc);
 127                         bitset_add_irn(visited, desc);
 128                 }
 129         }
 130
 131         foreach_out_edge_kind(irn, edge, EDGE_KIND_DEP) {
 132                 ir_node *desc = get_edge_src_irn(edge);
 133                 if(valid_node(env, desc) && !bitset_contains_irn(visited, desc)) {
 134                         obstack_ptr_grow(&env->obst, desc);
 135                         bitset_add_irn(visited, desc);
 136                 }
 137         }
 138 }
 139
 140 static ir_node **all_descendants(mris_env_t *env, ir_node *irn)
 141 {
 142         bitset_t *visited = bitset_irg_malloc(env->irg);
 143
 144         grow_all_descendands(env, irn, visited);
 145
 146 #if 0
 147         if(get_irn_mode(irn) == mode_T) {
 148                 const ir_edge_t *edge;
 149                 foreach_out_edge(irn, edge) {
 150                         ir_node *desc = get_edge_src_irn(edge);
 151                         assert(is_Proj(desc) && get_irn_mode(desc) != mode_T);
 152                         grow_all_descendands(env, desc, visited);
 153                 }
 154         }
 155
 156         else
 157                 grow_all_descendands(env, irn, visited);
 158 #endif
 159         bitset_free(visited);
 160         obstack_ptr_grow(&env->obst, NULL);
 161         return obstack_finish(&env->obst);
 162 }
 163
 164 static ir_node *put_lowest_in_front(mris_env_t *env, ir_node **in)
 165 {
 166         int lowest_index       = 0;
 167         unsigned lowest_height = INT_MAX;
 168         int i;
 169
 170         for(i = 0; in[i]; ++i) {
 171                 unsigned height = get_irn_height(env->heights, in[i]);
 172                 if(height < lowest_height) {
 173                         lowest_height = height;
 174                         lowest_index  = i;
 175                 }
 176         }
 177
 178         if(i > 0) {
 179                 ir_node *tmp     = in[0];
 180                 in[0]            = in[lowest_index];
 181                 in[lowest_index] = tmp;
 182         }
 183
 184         return in[0];
 185 }
 186
 187 #if 0
 188 static void reaches_walker(mris_env_t *env, ir_node *irn, ir_node *tgt, int *found, unsigned long visited)
 189 {
 190         if(get_irn_visited(irn) < visited && get_nodes_block(irn) == env->bl) {
 191
 192                 set_irn_visited(irn, visited);
 193
 194                 if(irn == tgt)
 195                         *found = 1;
 196                 else {
 197                         int i, n;
 198
 199                         for(i = 0, n = get_irn_arity(irn); i < n; ++i) {
 200                                 ir_node *op = get_irn_n(irn, i);
 201                                 if(!*found)
 202                                         reaches_walker(env, op, tgt, found, visited);
 203                         }
 204                 }
 205         }
 206 }
 207
 208 static int reaches(mris_env_t *env, ir_node *src, ir_node *tgt)
 209 {
 210         int found = 0;
 211         unsigned long visited = get_irg_visited(env->irg) + 1;
 212
 213         set_irg_visited(env->irg, visited);
 214         reaches_walker(env, src, tgt, &found, visited);
 215         return found;
 216 }
 217 #endif
 218
 219 static INLINE ir_node *skip_Projs(ir_node *irn)
 220 {
 221         return is_Proj(irn) ? skip_Projs(get_Proj_pred(irn)) : irn;
 222 }
 223
 224 #if 0
 225 static void replace_tuple_by_repr_proj(mris_env_t *env, ir_node **in)
 226 {
 227         int i;
 228
 229         for(i = 0; in[i]; ++i) {
 230                 if(get_irn_mode(in[i]) == mode_T) {
 231                         const ir_edge_t *edge;
 232                         ir_node *proj  = NULL;
 233                         ir_node *first = NULL;
 234
 235                         foreach_out_edge(in[i], edge) {
 236                                 ir_node *desc = get_edge_src_irn(edge);
 237
 238                                 first = first ? first : desc;
 239                                 if(get_irn_mode(desc) == mode_M) {
 240                                         proj = desc;
 241                                         break;
 242                                 }
 243                         }
 244
 245                         proj = proj ? proj : first;
 246                         assert(proj);
 247                         in[i] = proj;
 248                 }
 249         }
 250 }
 251 #endif
 252
 253 static void lineage_formation(mris_env_t *env)
 254 {
 255         firm_dbg_module_t *dbg = env->dbg;
 256         nodeset *nodes         = new_nodeset(128);
 257
 258         const ir_edge_t *edge;
 259
 260         foreach_out_edge(env->bl, edge) {
 261                 ir_node *irn = get_edge_src_irn(edge);
 262                 if(to_appear(env, irn))
 263                         nodeset_insert(nodes, irn);
 264         }
 265
 266         while(nodeset_count(nodes) > 0) {
 267                 mris_irn_t *mi;
 268                 ir_node *irn;
 269                 ir_node *highest_node = NULL;
 270                 ir_node *lowest_desc  = NULL;
 271                 ir_node *start;
 272                 mris_irn_t *start_mi;
 273
 274                 ir_node **in;
 275                 int recompute_height  = 0;
 276                 unsigned  curr_height = 0;
 277
 278                 /* search the highest node which is not yet in a lineage. */
 279                 for(irn = nodeset_first(nodes); irn; irn = nodeset_next(nodes)) {
 280                         unsigned height = get_irn_height(env->heights, irn);
 281                         if(height > curr_height) {
 282                                 highest_node = irn;
 283                                 curr_height  = height;
 284                         }
 285                 }
 286
 287                 assert(highest_node);
 288                 DBG((dbg, LEVEL_2, "highest node is %+F height %d\n", highest_node, get_irn_height(env->heights, highest_node)));
 289
 290                 start = highest_node;
 291                 mi = start_mi = get_mris_irn(env, highest_node);
 292
 293                 /* start a lineage beginning with highest_node. */
 294                 mi->lineage_start = highest_node;
 295                 mi->lineage_next  = NULL;
 296                 mi->lineage_end   = NULL;
 297                 list_add(&mi->lineage_list, &env->lineage_head);
 298                 nodeset_remove(nodes, highest_node);
 299
 300                 /*
 301                         put all descendants in an array.
 302                         we also move the lowest descendant in front, so that the other nodes
 303                         are easily accessible as an array, too.
 304                 */
 305                 in          = all_descendants(env, highest_node);
 306                 lowest_desc = put_lowest_in_front(env, in);
 307
 308                 /* as long as the current highest node has still descendants */
 309                 while(lowest_desc) {
 310                         mris_irn_t *lowest_mi  = get_mris_irn(env, lowest_desc);
 311                         mris_irn_t *highest_mi = get_mris_irn(env, highest_node);
 312                         int highest_is_tuple   = get_irn_mode(highest_node) == mode_T;
 313
 314                         int n_desc;
 315
 316                         DBG((dbg, LEVEL_2, "\tlowest descendant %+F height %d\n", lowest_desc, get_irn_height(env->heights, lowest_desc)));
 317
 318                         /* count the number of all descendants which are not the lowest descendant */
 319                         for(n_desc = 0; in[n_desc]; ++n_desc);
 320
 321                         /*
 322                         we insert a CopyKeep node to express the artificial dependencies from the lowest
 323                         descendant to all other descendants.
 324                         */
 325                         if(n_desc > 1 && !be_is_Keep(lowest_desc)) {
 326                                 ir_node *op;
 327                                 int i, n;
 328
 329                                 for(i = 0, n = get_irn_ins_or_deps(lowest_desc); i < n; ++i) {
 330                                         ir_node *cmp;
 331
 332                                         op  = get_irn_in_or_dep(lowest_desc, i);
 333                                         cmp = highest_is_tuple ? skip_Projs(op) : op;
 334
 335                                         // if(cmp == highest_node)
 336                                         if(op == highest_node)
 337                                                 break;
 338                                 }
 339
 340                                 assert(i < n && "could not find operand");
 341
 342                                 //replace_tuple_by_repr_proj(env, &in[1]);
 343                                 if(!is_Proj(lowest_desc))
 344                                         add_irn_dep(lowest_desc, in[1]);
 345                         }
 346                         obstack_free(&env->obst, in);
 347
 348                         /* if the current lowest node is not yet in a lineage, add it to the current one. */
 349                         if(!lowest_mi->lineage_start) {
 350                                 /* mark the current lowest node as the last one in the lineage. */
 351                                 highest_mi->lineage_next = lowest_desc;
 352                                 start_mi->lineage_end    = lowest_desc;
 353
 354                                 lowest_mi->lineage_start = start;
 355                                 nodeset_remove(nodes, lowest_desc);
 356                         }
 357
 358                         /* else we cannot extend this lineage, so break. */
 359                         else
 360                                 break;
 361
 362                         highest_node = lowest_desc;
 363                         highest_mi   = lowest_mi;
 364
 365                         /* recompute the descendants array and the new lowest descendant. */
 366                         in          = all_descendants(env, highest_node);
 367                         lowest_desc = put_lowest_in_front(env, in);
 368                 }
 369
 370                 /* recompute the heights if desired. */
 371                 if(recompute_height)
 372                         heights_recompute(env->heights);
 373         }
 374 }
 375
 376 static int fuse_two_lineages(mris_env_t *env, mris_irn_t *u, mris_irn_t *v)
 377 {
 378         mris_irn_t *mi;
 379         ir_node *irn, *last;
 380         ir_node *u_end   = u->lineage_end;
 381         ir_node *v_start = v->lineage_start;
 382         ir_node *start   = skip_Projs(v_start);
 383
 384         if(be_is_Keep(start))
 385                 return 0;
 386
 387         /* set lineage end of nodes in u to end of v. */
 388         irn = last = u->lineage_start;
 389         mi         = get_mris_irn(env, irn);
 390         while(irn && irn != u_end) {
 391                 mi = get_mris_irn(env, irn);
 392                 mi->lineage_end = v->lineage_end;
 393                 last = irn;
 394                 irn = mi->lineage_next;
 395         }
 396
 397         /* insert a CopyKeep to make lineage v dependent on u. */
 398         if(get_irn_ins_or_deps(start) == 0)
 399                 return 0;
 400
 401         if(get_irn_mode(last) == mode_T) {
 402                 const ir_edge_t *edge;
 403                 foreach_out_edge(last, edge) {
 404                         last = get_edge_src_irn(edge);
 405                         break;
 406                 }
 407         }
 408
 409         /* irn now points to the last node in lineage u; mi has the info for the node _before_ the terminator of the lineage. */
 410         mi->lineage_next       = v_start;
 411
 412         /* add a dependency from the first node in v's lineage to the last in u's */
 413         add_irn_dep(u_end, v_start);
 414
 415         /* set lineage start of nodes in v to start of u. */
 416         irn = v->lineage_start;
 417         while(irn && irn != v->lineage_end) {
 418                 mris_irn_t *mi = get_mris_irn(env, irn);
 419                 mi->lineage_start = u->lineage_start;
 420                 irn = mi->lineage_next;
 421         }
 422
 423         heights_recompute(env->heights);
 424
 425         mi = get_mris_irn(env, v_start);
 426         list_del(&mi->lineage_list);
 427
 428         return 1;
 429 }
 430
 431 static void fuse_lineages(mris_env_t *env)
 432 {
 433         mris_irn_t *u, *v, *tmp1, *tmp2;
 434
 435 again:
 436         foreach_lineage(env, u, tmp1) {
 437                 foreach_lineage(env, v, tmp2) {
 438                         if(u != v && u->lineage_start && v->lineage_start && u->lineage_end && v->lineage_end
 439                                 && get_nodes_block(u->lineage_start) == get_nodes_block(v->lineage_start)) {
 440                                 int uv = heights_reachable_in_block(env->heights, u->lineage_start, v->lineage_end);
 441                                 int vu = heights_reachable_in_block(env->heights, v->lineage_start, u->lineage_end);
 442
 443                                 if(uv && !vu) {
 444                                         if(fuse_two_lineages(env, u, v))
 445                                                 goto again;
 446                                 }
 447                         }
 448                 }
 449         }
 450 }
 451
 452 static mris_env_t *dump_env = NULL;
 453
 454 static void block_walker(ir_node *bl, void *data)
 455 {
 456         mris_env_t *env = data;
 457         env->bl = bl;
 458         lineage_formation(env);
 459         fuse_lineages(env);
 460 }
 461
 462 static int mris_edge_hook(FILE *F, ir_node *irn)
 463 {
 464         mris_irn_t *mi = get_mris_irn(dump_env, irn);
 465
 466         if(mi->lineage_next) {
 467                 fprintf(F, "edge:{sourcename:\"");
 468                 PRINT_NODEID(mi->lineage_next);
 469                 fprintf(F, "\" targetname:\"");
 470                 PRINT_NODEID(irn);
 471                 fprintf(F, "\" color:lilac}\n");
 472         }
 473         return 1;
 474 }
 475
 476 void dump_ir_block_graph_mris(mris_env_t *env, const char *suffix) {
 477         DUMP_NODE_EDGE_FUNC old = get_dump_node_edge_hook();
 478
 479         dump_consts_local(0);
 480         set_dump_node_edge_hook(mris_edge_hook);
 481         dump_env = env;
 482         dump_ir_block_graph(env->irg, suffix);
 483         set_dump_node_edge_hook(old);
 484 }
 485
 486 mris_env_t *be_sched_mris_preprocess(const be_irg_t *birg)
 487 {
 488         mris_env_t *env = xmalloc(sizeof(env[0]));
 489
 490         phase_init(&env->ph, "mris", birg->irg, 2 * PHASE_DEFAULT_GROWTH, mris_irn_data_init);
 491         env->aenv     = birg->main_env->arch_env;
 492         env->irg      = birg->irg;
 493         env->visited  = 0;
 494         env->heights  = heights_new(birg->irg);
 495         INIT_LIST_HEAD(&env->lineage_head);
 496         FIRM_DBG_REGISTER(env->dbg, "firm.be.sched.mris");
 497         obstack_init(&env->obst);
 498         irg_walk_graph(env->irg, firm_clear_link, NULL, NULL);
 499         irg_block_walk_graph(birg->irg, block_walker, NULL, env);
 500         obstack_free(&env->obst, NULL);
 501         // dump_ir_block_graph_mris(env, "-mris");
 502         return env;
 503 }
 504
 505 void be_sched_mris_free(mris_env_t *env)
 506 {
 507         phase_free(&env->ph);
 508         heights_free(env->heights);
 509         free(env);
 510 }