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