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 #include "benodesets.h"
  34
  35 struct _mris_env_t {
  36         phase_t            ph;
  37         heights_t         *heights;
  38         const arch_env_t  *aenv;
  39         ir_graph          *irg;
  40         ir_node           *bl;
  41         int               visited;
  42         struct list_head  lineage_head;
  43         struct obstack    obst;
  44         DEBUG_ONLY(firm_dbg_module_t *dbg;)
  45 };
  46
  47 typedef struct _mris_irn_t {
  48         int visited;
  49         ir_node *lineage_start;
  50         ir_node *lineage_next;
  51         ir_node *lineage_end;
  52         struct list_head lineage_list;
  53 } mris_irn_t;
  54
  55 #define to_appear(env, irn) (to_appear_in_schedule(irn) && get_nodes_block(irn) == env->bl)
  56
  57 #define get_mris_irn(env, irn)   ((mris_irn_t *) phase_get_or_set_irn_data(&env->ph, irn))
  58 #define foreach_lineage(env, pos, tmp) list_for_each_entry_safe(mris_irn_t, pos, tmp, &(env)->lineage_head, lineage_list)
  59
  60 static void *mris_irn_data_init(phase_t *ph, ir_node *irn, void *data)
  61 {
  62         mris_irn_t *mi = data ? data : phase_alloc(ph, sizeof(mi[0]));
  63         memset(mi, 0, sizeof(mi[0]));
  64         INIT_LIST_HEAD(&mi->lineage_list);
  65         return mi;
  66 }
  67
  68 #if 0
  69 static int compute_height(mris_env_t *env, ir_node *irn, unsigned long visited)
  70 {
  71         mris_irn_t *mi = get_mris_irn(env, irn);
  72
  73         if(get_irn_visited(irn) >= visited) {
  74                 DBG((env->dbg, LEVEL_3, "\theight of %+F = %d\n", irn, mi->height));
  75                 return mi->height;
  76         }
  77
  78         else {
  79                 const ir_edge_t *edge;
  80
  81                 set_irn_visited(irn, visited);
  82                 mi->height  = 0;
  83
  84                 foreach_out_edge(irn, edge) {
  85                         ir_node *dep = get_edge_src_irn(edge);
  86
  87                         if(!is_Block(dep) && get_nodes_block(dep) == env->bl) {
  88                                 int dep_height = compute_height(env, dep, visited);
  89                                 mi->height     = MAX(mi->height, dep_height);
  90                         }
  91                 }
  92
  93                 mi->height++;
  94                 DBG((env->dbg, LEVEL_3, "\tsetting height of %+F = %d\n", irn, mi->height));
  95         }
  96
  97         return mi->height;
  98 }
  99
 100 static void compute_heights(mris_env_t *env)
 101 {
 102         const ir_edge_t *edge;
 103         unsigned long visited;
 104
 105         visited = get_irg_visited(env->irg) + 1;
 106         set_irg_visited(env->irg, visited);
 107
 108         foreach_out_edge(env->bl, edge) {
 109                 ir_node *dep = get_edge_src_irn(edge);
 110                 if(to_appear(env, dep))
 111                         compute_height(env, dep, visited);
 112         }
 113 }
 114 #endif
 115
 116 #define valid_node(env, dep) (to_appear(env, dep) && !be_is_Keep(dep))
 117
 118 static void grow_all_descendands(mris_env_t *env, ir_node *irn, bitset_t *visited)
 119 {
 120         const ir_edge_t *edge;
 121
 122         // assert(get_irn_mode(irn) != mode_T);
 123
 124         foreach_out_edge(irn, edge) {
 125                 ir_node *desc = get_edge_src_irn(edge);
 126                 if(valid_node(env, desc) && !bitset_contains_irn(visited, desc)) {
 127                         obstack_ptr_grow(&env->obst, desc);
 128                         bitset_add_irn(visited, desc);
 129                 }
 130         }
 131
 132         foreach_out_edge_kind(irn, edge, EDGE_KIND_DEP) {
 133                 ir_node *desc = get_edge_src_irn(edge);
 134                 if(valid_node(env, desc) && !bitset_contains_irn(visited, desc)) {
 135                         obstack_ptr_grow(&env->obst, desc);
 136                         bitset_add_irn(visited, desc);
 137                 }
 138         }
 139 }
 140
 141 static ir_node **all_descendants(mris_env_t *env, ir_node *irn)
 142 {
 143         bitset_t *visited = bitset_irg_malloc(env->irg);
 144
 145         grow_all_descendands(env, irn, visited);
 146
 147 #if 0
 148         if(get_irn_mode(irn) == mode_T) {
 149                 const ir_edge_t *edge;
 150                 foreach_out_edge(irn, edge) {
 151                         ir_node *desc = get_edge_src_irn(edge);
 152                         assert(is_Proj(desc) && get_irn_mode(desc) != mode_T);
 153                         grow_all_descendands(env, desc, visited);
 154                 }
 155         }
 156
 157         else
 158                 grow_all_descendands(env, irn, visited);
 159 #endif
 160         bitset_free(visited);
 161         obstack_ptr_grow(&env->obst, NULL);
 162         return obstack_finish(&env->obst);
 163 }
 164
 165 static ir_node *put_lowest_in_front(mris_env_t *env, ir_node **in)
 166 {
 167         int lowest_index       = 0;
 168         unsigned lowest_height = INT_MAX;
 169         int i;
 170
 171         for(i = 0; in[i]; ++i) {
 172                 unsigned height = get_irn_height(env->heights, in[i]);
 173                 if(height < lowest_height) {
 174                         lowest_height = height;
 175                         lowest_index  = i;
 176                 }
 177         }
 178
 179         if(i > 0) {
 180                 ir_node *tmp     = in[0];
 181                 in[0]            = in[lowest_index];
 182                 in[lowest_index] = tmp;
 183         }
 184
 185         return in[0];
 186 }
 187
 188 #if 0
 189 static void reaches_walker(mris_env_t *env, ir_node *irn, ir_node *tgt, int *found, unsigned long visited)
 190 {
 191         if(get_irn_visited(irn) < visited && get_nodes_block(irn) == env->bl) {
 192
 193                 set_irn_visited(irn, visited);
 194
 195                 if(irn == tgt)
 196                         *found = 1;
 197                 else {
 198                         int i, n;
 199
 200                         for(i = 0, n = get_irn_arity(irn); i < n; ++i) {
 201                                 ir_node *op = get_irn_n(irn, i);
 202                                 if(!*found)
 203                                         reaches_walker(env, op, tgt, found, visited);
 204                         }
 205                 }
 206         }
 207 }
 208
 209 static int reaches(mris_env_t *env, ir_node *src, ir_node *tgt)
 210 {
 211         int found = 0;
 212         unsigned long visited = get_irg_visited(env->irg) + 1;
 213
 214         set_irg_visited(env->irg, visited);
 215         reaches_walker(env, src, tgt, &found, visited);
 216         return found;
 217 }
 218 #endif
 219
 220 static INLINE ir_node *skip_Projs(ir_node *irn)
 221 {
 222         return is_Proj(irn) ? skip_Projs(get_Proj_pred(irn)) : irn;
 223 }
 224
 225 #if 0
 226 static void replace_tuple_by_repr_proj(mris_env_t *env, ir_node **in)
 227 {
 228         int i;
 229
 230         for(i = 0; in[i]; ++i) {
 231                 if(get_irn_mode(in[i]) == mode_T) {
 232                         const ir_edge_t *edge;
 233                         ir_node *proj  = NULL;
 234                         ir_node *first = NULL;
 235
 236                         foreach_out_edge(in[i], edge) {
 237                                 ir_node *desc = get_edge_src_irn(edge);
 238
 239                                 first = first ? first : desc;
 240                                 if(get_irn_mode(desc) == mode_M) {
 241                                         proj = desc;
 242                                         break;
 243                                 }
 244                         }
 245
 246                         proj = proj ? proj : first;
 247                         assert(proj);
 248                         in[i] = proj;
 249                 }
 250         }
 251 }
 252 #endif
 253
 254 static void lineage_formation(mris_env_t *env)
 255 {
 256         DEBUG_ONLY(firm_dbg_module_t *dbg = env->dbg);
 257         nodeset *nodes         = new_nodeset(128);
 258
 259         const ir_edge_t *edge;
 260
 261         foreach_out_edge(env->bl, edge) {
 262                 ir_node *irn = get_edge_src_irn(edge);
 263                 if(to_appear(env, irn))
 264                         nodeset_insert(nodes, irn);
 265         }
 266
 267         while(nodeset_count(nodes) > 0) {
 268                 mris_irn_t *mi;
 269                 ir_node *irn;
 270                 ir_node *highest_node = NULL;
 271                 ir_node *lowest_desc  = NULL;
 272                 ir_node *start;
 273                 mris_irn_t *start_mi;
 274
 275                 ir_node **in;
 276                 int recompute_height  = 0;
 277                 unsigned  curr_height = 0;
 278
 279                 /* search the highest node which is not yet in a lineage. */
 280                 for(irn = nodeset_first(nodes); irn; irn = nodeset_next(nodes)) {
 281                         unsigned height = get_irn_height(env->heights, irn);
 282                         if(height > curr_height) {
 283                                 highest_node = irn;
 284                                 curr_height  = height;
 285                         }
 286                 }
 287
 288                 assert(highest_node);
 289                 DBG((dbg, LEVEL_2, "highest node is %+F height %d\n", highest_node, get_irn_height(env->heights, highest_node)));
 290
 291                 start = highest_node;
 292                 mi = start_mi = get_mris_irn(env, highest_node);
 293
 294                 /* start a lineage beginning with highest_node. */
 295                 mi->lineage_start = highest_node;
 296                 mi->lineage_next  = NULL;
 297                 mi->lineage_end   = NULL;
 298                 list_add(&mi->lineage_list, &env->lineage_head);
 299                 nodeset_remove(nodes, highest_node);
 300
 301                 /*
 302                         put all descendants in an array.
 303                         we also move the lowest descendant in front, so that the other nodes
 304                         are easily accessible as an array, too.
 305                 */
 306                 in          = all_descendants(env, highest_node);
 307                 lowest_desc = put_lowest_in_front(env, in);
 308
 309                 /* as long as the current highest node has still descendants */
 310                 while(lowest_desc) {
 311                         mris_irn_t *lowest_mi  = get_mris_irn(env, lowest_desc);
 312                         mris_irn_t *highest_mi = get_mris_irn(env, highest_node);
 313                         int highest_is_tuple   = get_irn_mode(highest_node) == mode_T;
 314
 315                         int n_desc;
 316
 317                         DBG((dbg, LEVEL_2, "\tlowest descendant %+F height %d\n", lowest_desc, get_irn_height(env->heights, lowest_desc)));
 318
 319                         /* count the number of all descendants which are not the lowest descendant */
 320                         for(n_desc = 0; in[n_desc]; ++n_desc);
 321
 322                         /*
 323                         we insert a CopyKeep node to express the artificial dependencies from the lowest
 324                         descendant to all other descendants.
 325                         */
 326                         if(n_desc > 1 && !be_is_Keep(lowest_desc)) {
 327                                 ir_node *op;
 328                                 int i, n;
 329
 330                                 for(i = 0, n = get_irn_ins_or_deps(lowest_desc); i < n; ++i) {
 331                                         ir_node *cmp;
 332
 333                                         op  = get_irn_in_or_dep(lowest_desc, i);
 334                                         cmp = highest_is_tuple ? skip_Projs(op) : op;
 335
 336                                         // if(cmp == highest_node)
 337                                         if(op == highest_node)
 338                                                 break;
 339                                 }
 340
 341                                 assert(i < n && "could not find operand");
 342
 343                                 //replace_tuple_by_repr_proj(env, &in[1]);
 344                                 if(!is_Proj(lowest_desc))
 345                                         add_irn_dep(lowest_desc, in[1]);
 346                         }
 347                         obstack_free(&env->obst, in);
 348
 349                         /* if the current lowest node is not yet in a lineage, add it to the current one. */
 350                         if(!lowest_mi->lineage_start) {
 351                                 /* mark the current lowest node as the last one in the lineage. */
 352                                 highest_mi->lineage_next = lowest_desc;
 353                                 start_mi->lineage_end    = lowest_desc;
 354
 355                                 lowest_mi->lineage_start = start;
 356                                 nodeset_remove(nodes, lowest_desc);
 357                         }
 358
 359                         /* else we cannot extend this lineage, so break. */
 360                         else
 361                                 break;
 362
 363                         highest_node = lowest_desc;
 364                         highest_mi   = lowest_mi;
 365
 366                         /* recompute the descendants array and the new lowest descendant. */
 367                         in          = all_descendants(env, highest_node);
 368                         lowest_desc = put_lowest_in_front(env, in);
 369                 }
 370
 371                 /* recompute the heights if desired. */
 372                 if(recompute_height)
 373                         heights_recompute(env->heights);
 374         }
 375 }
 376
 377 static int fuse_two_lineages(mris_env_t *env, mris_irn_t *u, mris_irn_t *v)
 378 {
 379         mris_irn_t *mi;
 380         ir_node *irn, *last;
 381         ir_node *u_end   = u->lineage_end;
 382         ir_node *v_start = v->lineage_start;
 383         ir_node *start   = skip_Projs(v_start);
 384
 385         if(be_is_Keep(start))
 386                 return 0;
 387
 388         /* set lineage end of nodes in u to end of v. */
 389         irn = last = u->lineage_start;
 390         mi         = get_mris_irn(env, irn);
 391         while(irn && irn != u_end) {
 392                 mi = get_mris_irn(env, irn);
 393                 mi->lineage_end = v->lineage_end;
 394                 last = irn;
 395                 irn = mi->lineage_next;
 396         }
 397
 398         /* insert a CopyKeep to make lineage v dependent on u. */
 399         if(get_irn_ins_or_deps(start) == 0)
 400                 return 0;
 401
 402         if(get_irn_mode(last) == mode_T) {
 403                 const ir_edge_t *edge;
 404                 foreach_out_edge(last, edge) {
 405                         last = get_edge_src_irn(edge);
 406                         break;
 407                 }
 408         }
 409
 410         /* irn now points to the last node in lineage u; mi has the info for the node _before_ the terminator of the lineage. */
 411         mi->lineage_next       = v_start;
 412
 413         /* add a dependency from the first node in v's lineage to the last in u's */
 414         add_irn_dep(u_end, v_start);
 415
 416         /* set lineage start of nodes in v to start of u. */
 417         irn = v->lineage_start;
 418         while(irn && irn != v->lineage_end) {
 419                 mris_irn_t *mi = get_mris_irn(env, irn);
 420                 mi->lineage_start = u->lineage_start;
 421                 irn = mi->lineage_next;
 422         }
 423
 424         heights_recompute(env->heights);
 425
 426         mi = get_mris_irn(env, v_start);
 427         list_del(&mi->lineage_list);
 428
 429         return 1;
 430 }
 431
 432 static void fuse_lineages(mris_env_t *env)
 433 {
 434         mris_irn_t *u, *v, *tmp1, *tmp2;
 435
 436 again:
 437         foreach_lineage(env, u, tmp1) {
 438                 foreach_lineage(env, v, tmp2) {
 439                         if(u != v && u->lineage_start && v->lineage_start && u->lineage_end && v->lineage_end
 440                                 && get_nodes_block(u->lineage_start) == get_nodes_block(v->lineage_start)) {
 441                                 int uv = heights_reachable_in_block(env->heights, u->lineage_start, v->lineage_end);
 442                                 int vu = heights_reachable_in_block(env->heights, v->lineage_start, u->lineage_end);
 443
 444                                 if(uv && !vu) {
 445                                         if(fuse_two_lineages(env, u, v))
 446                                                 goto again;
 447                                 }
 448                         }
 449                 }
 450         }
 451 }
 452
 453 static mris_env_t *dump_env = NULL;
 454
 455 static void block_walker(ir_node *bl, void *data)
 456 {
 457         mris_env_t *env = data;
 458         env->bl = bl;
 459         lineage_formation(env);
 460         fuse_lineages(env);
 461 }
 462
 463 static int mris_edge_hook(FILE *F, ir_node *irn)
 464 {
 465         mris_irn_t *mi = get_mris_irn(dump_env, irn);
 466
 467         if(mi->lineage_next) {
 468                 fprintf(F, "edge:{sourcename:\"");
 469                 PRINT_NODEID(mi->lineage_next);
 470                 fprintf(F, "\" targetname:\"");
 471                 PRINT_NODEID(irn);
 472                 fprintf(F, "\" color:lilac}\n");
 473         }
 474         return 1;
 475 }
 476
 477 void dump_ir_block_graph_mris(mris_env_t *env, const char *suffix) {
 478         DUMP_NODE_EDGE_FUNC old = get_dump_node_edge_hook();
 479
 480         dump_consts_local(0);
 481         set_dump_node_edge_hook(mris_edge_hook);
 482         dump_env = env;
 483         dump_ir_block_graph(env->irg, suffix);
 484         set_dump_node_edge_hook(old);
 485 }
 486
 487 mris_env_t *be_sched_mris_preprocess(const be_irg_t *birg)
 488 {
 489         mris_env_t *env = xmalloc(sizeof(env[0]));
 490
 491         phase_init(&env->ph, "mris", birg->irg, 2 * PHASE_DEFAULT_GROWTH, mris_irn_data_init);
 492         env->aenv     = birg->main_env->arch_env;
 493         env->irg      = birg->irg;
 494         env->visited  = 0;
 495         env->heights  = heights_new(birg->irg);
 496         INIT_LIST_HEAD(&env->lineage_head);
 497         FIRM_DBG_REGISTER(env->dbg, "firm.be.sched.mris");
 498         obstack_init(&env->obst);
 499         irg_walk_graph(env->irg, firm_clear_link, NULL, NULL);
 500         irg_block_walk_graph(birg->irg, block_walker, NULL, env);
 501         obstack_free(&env->obst, NULL);
 502         // dump_ir_block_graph_mris(env, "-mris");
 503         return env;
 504 }
 505
 506 void be_sched_mris_free(mris_env_t *env)
 507 {
 508         phase_free(&env->ph);
 509         heights_free(env->heights);
 510         free(env);
 511 }