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         const ir_edge_t *edge;
 144
 145         grow_all_descendands(env, irn, visited);
 146
 147 #if 0
 148         if(get_irn_mode(irn) == mode_T) {
 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 static void replace_tuple_by_repr_proj(mris_env_t *env, ir_node **in)
 225 {
 226         int i;
 227
 228         for(i = 0; in[i]; ++i) {
 229                 if(get_irn_mode(in[i]) == mode_T) {
 230                         const ir_edge_t *edge;
 231                         ir_node *proj  = NULL;
 232                         ir_node *first = NULL;
 233
 234                         foreach_out_edge(in[i], edge) {
 235                                 ir_node *desc = get_edge_src_irn(edge);
 236
 237                                 first = first ? first : desc;
 238                                 if(get_irn_mode(desc) == mode_M) {
 239                                         proj = desc;
 240                                         break;
 241                                 }
 242                         }
 243
 244                         proj = proj ? proj : first;
 245                         assert(proj);
 246                         in[i] = proj;
 247                 }
 248         }
 249 }
 250
 251 static void lineage_formation(mris_env_t *env)
 252 {
 253         firm_dbg_module_t *dbg = env->dbg;
 254         nodeset *nodes         = new_nodeset(128);
 255
 256         const ir_edge_t *edge;
 257
 258         foreach_out_edge(env->bl, edge) {
 259                 ir_node *irn = get_edge_src_irn(edge);
 260                 if(to_appear(env, irn))
 261                         nodeset_insert(nodes, irn);
 262         }
 263
 264         while(nodeset_count(nodes) > 0) {
 265                 mris_irn_t *mi;
 266                 ir_node *irn;
 267                 ir_node *highest_node = NULL;
 268                 ir_node *lowest_desc  = NULL;
 269                 ir_node *start;
 270                 mris_irn_t *start_mi;
 271
 272                 ir_node **in;
 273                 int recompute_height  = 0;
 274                 unsigned  curr_height = 0;
 275
 276                 /* search the highest node which is not yet in a lineage. */
 277                 for(irn = nodeset_first(nodes); irn; irn = nodeset_next(nodes)) {
 278                         unsigned height = get_irn_height(env->heights, irn);
 279                         if(height > curr_height) {
 280                                 highest_node = irn;
 281                                 curr_height  = height;
 282                         }
 283                 }
 284
 285                 assert(highest_node);
 286                 DBG((dbg, LEVEL_2, "highest node is %+F height %d\n", highest_node, get_irn_height(env->heights, highest_node)));
 287
 288                 start = highest_node;
 289                 mi = start_mi = get_mris_irn(env, highest_node);
 290
 291                 /* start a lineage beginning with highest_node. */
 292                 mi->lineage_start = highest_node;
 293                 mi->lineage_next  = NULL;
 294                 mi->lineage_end   = NULL;
 295                 list_add(&mi->lineage_list, &env->lineage_head);
 296                 nodeset_remove(nodes, highest_node);
 297
 298                 /*
 299                         put all descendants in an array.
 300                         we also move the lowest descendant in front, so that the other nodes
 301                         are easily accessible as an array, too.
 302                 */
 303                 in          = all_descendants(env, highest_node);
 304                 lowest_desc = put_lowest_in_front(env, in);
 305
 306                 /* as long as the current highest node has still descendants */
 307                 while(lowest_desc) {
 308                         mris_irn_t *lowest_mi  = get_mris_irn(env, lowest_desc);
 309                         mris_irn_t *highest_mi = get_mris_irn(env, highest_node);
 310                         int highest_is_tuple   = get_irn_mode(highest_node) == mode_T;
 311
 312                         int n_desc;
 313
 314                         DBG((dbg, LEVEL_2, "\tlowest descendant %+F height %d\n", lowest_desc, get_irn_height(env->heights, lowest_desc)));
 315
 316                         /* count the number of all descendants which are not the lowest descendant */
 317                         for(n_desc = 0; in[n_desc]; ++n_desc);
 318
 319                         /*
 320                         we insert a CopyKeep node to express the artificial dependencies from the lowest
 321                         descendant to all other descendants.
 322                         */
 323                         if(n_desc > 1 && !be_is_Keep(lowest_desc)) {
 324                                 ir_node *op;
 325                                 int i, n;
 326
 327                                 for(i = 0, n = get_irn_ins_or_deps(lowest_desc); i < n; ++i) {
 328                                         ir_node *cmp;
 329
 330                                         op  = get_irn_in_or_dep(lowest_desc, i);
 331                                         cmp = highest_is_tuple ? skip_Projs(op) : op;
 332
 333                                         // if(cmp == highest_node)
 334                                         if(op == highest_node)
 335                                                 break;
 336                                 }
 337
 338                                 assert(i < n && "could not find operand");
 339
 340                                 //replace_tuple_by_repr_proj(env, &in[1]);
 341                                 if(!is_Proj(lowest_desc))
 342                                         add_irn_dep(lowest_desc, in[1]);
 343                         }
 344                         obstack_free(&env->obst, in);
 345
 346                         /* if the current lowest node is not yet in a lineage, add it to the current one. */
 347                         if(!lowest_mi->lineage_start) {
 348                                 /* mark the current lowest node as the last one in the lineage. */
 349                                 highest_mi->lineage_next = lowest_desc;
 350                                 start_mi->lineage_end    = lowest_desc;
 351
 352                                 lowest_mi->lineage_start = start;
 353                                 nodeset_remove(nodes, lowest_desc);
 354                         }
 355
 356                         /* else we cannot extend this lineage, so break. */
 357                         else
 358                                 break;
 359
 360                         highest_node = lowest_desc;
 361                         highest_mi   = lowest_mi;
 362
 363                         /* recompute the descendants array and the new lowest descendant. */
 364                         in          = all_descendants(env, highest_node);
 365                         lowest_desc = put_lowest_in_front(env, in);
 366                 }
 367
 368                 /* recompute the heights if desired. */
 369                 if(recompute_height)
 370                         heights_recompute(env->heights);
 371         }
 372 }
 373
 374 static int fuse_two_lineages(mris_env_t *env, mris_irn_t *u, mris_irn_t *v)
 375 {
 376         mris_irn_t *mi;
 377         ir_node *irn, *last;
 378         ir_node *u_end   = u->lineage_end;
 379         ir_node *v_start = v->lineage_start;
 380         ir_node *start   = skip_Projs(v_start);
 381
 382         if(be_is_Keep(start))
 383                 return 0;
 384
 385         /* set lineage end of nodes in u to end of v. */
 386         irn = last = u->lineage_start;
 387         mi         = get_mris_irn(env, irn);
 388         while(irn && irn != u_end) {
 389                 mi = get_mris_irn(env, irn);
 390                 mi->lineage_end = v->lineage_end;
 391                 last = irn;
 392                 irn = mi->lineage_next;
 393         }
 394
 395         /* insert a CopyKeep to make lineage v dependent on u. */
 396         if(get_irn_ins_or_deps(start) == 0)
 397                 return 0;
 398
 399         if(get_irn_mode(last) == mode_T) {
 400                 const ir_edge_t *edge;
 401                 foreach_out_edge(last, edge) {
 402                         last = get_edge_src_irn(edge);
 403                         break;
 404                 }
 405         }
 406
 407         /* irn now points to the last node in lineage u; mi has the info for the node _before_ the terminator of the lineage. */
 408         mi->lineage_next       = v_start;
 409
 410         /* add a dependency from the first node in v's lineage to the last in u's */
 411         add_irn_dep(u_end, v_start);
 412
 413         /* set lineage start of nodes in v to start of u. */
 414         irn = v->lineage_start;
 415         while(irn && irn != v->lineage_end) {
 416                 mris_irn_t *mi = get_mris_irn(env, irn);
 417                 mi->lineage_start = u->lineage_start;
 418                 irn = mi->lineage_next;
 419         }
 420
 421         heights_recompute(env->heights);
 422
 423         mi = get_mris_irn(env, v_start);
 424         list_del(&mi->lineage_list);
 425
 426         return 1;
 427 }
 428
 429 static void fuse_lineages(mris_env_t *env)
 430 {
 431         mris_irn_t *u, *v, *tmp1, *tmp2;
 432
 433 again:
 434         foreach_lineage(env, u, tmp1) {
 435                 foreach_lineage(env, v, tmp2) {
 436                         if(u != v && u->lineage_start && v->lineage_start && u->lineage_end && v->lineage_end
 437                                 && get_nodes_block(u->lineage_start) == get_nodes_block(v->lineage_start)) {
 438                                 int uv = heights_reachable_in_block(env->heights, u->lineage_start, v->lineage_end);
 439                                 int vu = heights_reachable_in_block(env->heights, v->lineage_start, u->lineage_end);
 440
 441                                 if(uv && !vu) {
 442                                         if(fuse_two_lineages(env, u, v))
 443                                                 goto again;
 444                                 }
 445                         }
 446                 }
 447         }
 448 }
 449
 450 static mris_env_t *dump_env = NULL;
 451
 452 static void block_walker(ir_node *bl, void *data)
 453 {
 454         mris_env_t *env = data;
 455         env->bl = bl;
 456         lineage_formation(env);
 457         fuse_lineages(env);
 458 }
 459
 460 static int mris_edge_hook(FILE *F, ir_node *irn)
 461 {
 462         mris_irn_t *mi = get_mris_irn(dump_env, irn);
 463
 464         if(mi->lineage_next) {
 465                 fprintf(F, "edge:{sourcename:\"");
 466                 PRINT_NODEID(mi->lineage_next);
 467                 fprintf(F, "\" targetname:\"");
 468                 PRINT_NODEID(irn);
 469                 fprintf(F, "\" color:lilac}\n");
 470         }
 471         return 1;
 472 }
 473
 474 void dump_ir_block_graph_mris(mris_env_t *env, const char *suffix) {
 475         DUMP_NODE_EDGE_FUNC old = get_dump_node_edge_hook();
 476
 477         dump_consts_local(0);
 478         set_dump_node_edge_hook(mris_edge_hook);
 479         dump_env = env;
 480         dump_ir_block_graph(env->irg, suffix);
 481         set_dump_node_edge_hook(old);
 482 }
 483
 484 mris_env_t *be_sched_mris_preprocess(const be_irg_t *birg)
 485 {
 486         mris_env_t *env = xmalloc(sizeof(env[0]));
 487
 488         phase_init(&env->ph, "mris", birg->irg, 2 * PHASE_DEFAULT_GROWTH, mris_irn_data_init);
 489         env->aenv     = birg->main_env->arch_env;
 490         env->irg      = birg->irg;
 491         env->visited  = 0;
 492         env->heights  = heights_new(birg->irg);
 493         INIT_LIST_HEAD(&env->lineage_head);
 494         FIRM_DBG_REGISTER(env->dbg, "firm.be.sched.mris");
 495         obstack_init(&env->obst);
 496         irg_walk_graph(env->irg, firm_clear_link, NULL, NULL);
 497         irg_block_walk_graph(birg->irg, block_walker, NULL, env);
 498         obstack_free(&env->obst, NULL);
 499         dump_ir_block_graph_mris(env, "-mris");
 500         return env;
 501 }
 502
 503 void be_sched_mris_free(mris_env_t *env)
 504 {
 505         phase_free(&env->ph);
 506         heights_free(env->heights);
 507         free(env);
 508 }