nsz Git - libfirm/blob - ir/be/becopyilp2.c

   1 /**
   2  * Author:      Daniel Grund
   3  * Date:                28.02.2006
   4  * Copyright:   (c) Universitaet Karlsruhe
   5  * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
   6  *
   7  *
   8  * ILP formalization using G=(V, E, Q):
   9  *  - 2 class of variables: coloring vars x_ic   and   equal color vars y_ij
  10  *  - Path constraints
  11  *  - Clique-star constraints
  12  *
  13  *
  14  *      \min \sum_{ (i,j) \in Q }  w_ij y_ij
  15  *
  16  *              \sum_c x_nc                     =  1                    n \in N, c \in C
  17  *
  18  *              x_nc                            =  0                    n \in N, c \not\in C(n)
  19  *
  20  *              \sum x_nc                       <= 1                    x_nc \in Clique \in AllCliques,  c \in C
  21  *
  22  *              \sum_{e \in p} y_e      >= 1                    p \in P         path constraints
  23  *
  24  *              \sum_{e \in cs} y_e     >= |cs| - 1             cs \in CP       clique-star constraints
  25  *
  26  *              x_nc, y_ij \in N,   w_ij \in R^+
  27  */
  28
  29 #ifdef HAVE_CONFIG_H
  30 #include "config.h"
  31 #endif /* HAVE_CONFIG_H */
  32
  33 #include <bitset.h>
  34 #include "pdeq.h"
  35
  36 #include "irtools.h"
  37 #include "irgwalk.h"
  38 #include "becopyilp_t.h"
  39 #include "beifg_t.h"
  40 #include "besched_t.h"
  41
  42 #define DEBUG_LVL 1
  43
  44 typedef struct _local_env_t {
  45         firm_dbg_module_t *dbg;
  46         double time_limit;
  47         int first_x_var, last_x_var;
  48         pmap *nr_2_irn;
  49 } local_env_t;
  50
  51 static void build_coloring_cstr(ilp_env_t *ienv) {
  52         be_ifg_t *ifg = ienv->co->cenv->ifg;
  53         void *iter = be_ifg_nodes_iter_alloca(ifg);
  54         bitset_t *colors;
  55         ir_node *irn;
  56         char buf[16];
  57
  58         colors = bitset_alloca(arch_register_class_n_regs(ienv->co->cls));
  59
  60         be_ifg_foreach_node(ifg, iter, irn)
  61                 if (!sr_is_removed(ienv->sr, irn)) {
  62                         int col, cst_idx;
  63                         arch_register_req_t req;
  64                         int curr_node_color = get_irn_col(ienv->co, irn);
  65                         int node_nr = (int)get_irn_node_nr(irn);
  66                         local_env_t *lenv = ienv->env;
  67
  68                         pmap_insert(lenv->nr_2_irn, INT_TO_PTR(node_nr), irn);
  69
  70                         arch_get_register_req(ienv->co->aenv, &req, irn, -1);
  71
  72                         /* get assignable colors */
  73                         if (arch_register_req_is(&req, limited))
  74                                 req.limited(req.limited_env, colors);
  75                         else
  76                                 arch_put_non_ignore_regs(ienv->co->aenv, req.cls, colors);
  77
  78                         /* add the coloring constraint */
  79                         cst_idx = lpp_add_cst(ienv->lp, NULL, lpp_equal, 1.0);
  80
  81                         bitset_foreach(colors, col) {
  82                                 int var_idx = lpp_add_var(ienv->lp, name_cdd(buf, 'x', node_nr, col), lpp_binary, 0.0);
  83                                 lpp_set_start_value(ienv->lp, var_idx, (col == curr_node_color) ? 1.0 : 0.0);
  84                                 lpp_set_factor_fast(ienv->lp, cst_idx, var_idx, 1);
  85
  86                                 lenv->last_x_var = var_idx;
  87                                 if (lenv->first_x_var == -1)
  88                                         lenv->first_x_var = var_idx;
  89                         }
  90
  91                         /* add register constraint constraints */
  92                         bitset_foreach_clear(colors, col) {
  93                                 int cst_idx = lpp_add_cst(ienv->lp, NULL, lpp_equal, 0.0);
  94                                 int var_idx = lpp_add_var(ienv->lp, name_cdd(buf, 'x', node_nr, col), lpp_binary, 0.0);
  95                                 lpp_set_start_value(ienv->lp, var_idx, 0.0);
  96                                 lpp_set_factor_fast(ienv->lp, cst_idx, var_idx, 1);
  97
  98                                 lenv->last_x_var = var_idx;
  99                         }
 100                 }
 101 }
 102
 103 static void build_interference_cstr(ilp_env_t *ienv) {
 104         lpp_t *lpp = ienv->lp;
 105         be_ifg_t *ifg = ienv->co->cenv->ifg;
 106         int n_colors = arch_register_class_n_regs(ienv->co->cls);
 107         int i, col;
 108
 109         void *iter = be_ifg_cliques_iter_alloca(ifg);
 110         ir_node **clique = alloca(sizeof(*clique) * n_colors);
 111         int size;
 112
 113         char buf[16];
 114
 115         /* for each maximal clique */
 116         be_ifg_foreach_clique(ifg, iter, clique, &size) {
 117                 int realsize = 0;
 118
 119                 for (i=0; i<size; ++i)
 120                         if (!sr_is_removed(ienv->sr, clique[i]))
 121                                 ++realsize;
 122
 123                 if (realsize < 2)
 124                         continue;
 125
 126                 /* for all colors */
 127                 for (col=0; col<n_colors; ++col) {
 128                         int cst_idx = lpp_add_cst(lpp, NULL, lpp_less, 1.0);
 129
 130                         /* for each member of this clique */
 131                         for (i=0; i<size; ++i) {
 132                                 ir_node *irn = clique[i];
 133
 134                                 if (!sr_is_removed(ienv->sr, irn)) {
 135                                         int var_idx = lpp_get_var_idx(lpp, name_cdd(buf, 'x', (int)get_irn_node_nr(irn), col));
 136                                         lpp_set_factor_fast(lpp, cst_idx, var_idx, 1);
 137                                 }
 138                         }
 139                 }
 140         }
 141 }
 142
 143
 144 /**
 145  * TODO: Remove the dependency of the opt-units data structure
 146  *       by walking over all affinity edges. Graph structure
 147  *       does not provide this walker, yet.
 148  */
 149 static void build_affinity_cstr(ilp_env_t *ienv) {
 150         unit_t *curr;
 151         int n_colors = arch_register_class_n_regs(ienv->co->cls);
 152
 153         /* for all optimization units */
 154         list_for_each_entry(unit_t, curr, &ienv->co->units, units) {
 155                 ir_node *root, *arg;
 156                 int root_nr, arg_nr, i, col, y_idx, root_idx, arg_idx;
 157                 char buf[16];
 158                 int root_col, arg_col;
 159
 160                 root = curr->nodes[0];
 161                 root_nr = (int) get_irn_node_nr(root);
 162                 root_col = get_irn_col(ienv->co, root);
 163
 164                 for (i = 1; i < curr->node_count; ++i) {
 165                         arg = curr->nodes[i];
 166                         arg_nr = (int) get_irn_node_nr(arg);
 167                         arg_col = get_irn_col(ienv->co, arg);
 168
 169                         /* add a new affinity variable */
 170                         y_idx = lpp_add_var(ienv->lp, name_cdd_sorted(buf, 'y', root_nr, arg_nr), lpp_binary, curr->costs[i]);
 171                         lpp_set_start_value(ienv->lp, y_idx, (root_col==arg_col) ? 0.0 : 1.0);
 172
 173                         /* add constraints relating the affinity var to the color vars */
 174                         for (col=0; col<n_colors; ++col) {
 175                                 int cst_idx = lpp_add_cst(ienv->lp, NULL, lpp_less, 0.0);
 176                                 root_idx = lpp_get_var_idx(ienv->lp, name_cdd(buf, 'x', root_nr, col));
 177                                 arg_idx  = lpp_get_var_idx(ienv->lp, name_cdd(buf, 'x', arg_nr,  col));
 178
 179                                 lpp_set_factor_fast(ienv->lp, cst_idx, root_idx,  1.0);
 180                                 lpp_set_factor_fast(ienv->lp, cst_idx, arg_idx,  -1.0);
 181                                 lpp_set_factor_fast(ienv->lp, cst_idx, y_idx, -1.0);
 182                         }
 183                 }
 184         }
 185 }
 186
 187 /**
 188  * Helping stuff for build_clique_star_cstr
 189  */
 190 typedef struct _edge_t {
 191         ir_node *n1, *n2;
 192 } edge_t;
 193
 194 static int compare_edge_t(const void *k1, const void *k2, size_t size) {
 195         const edge_t *e1 = k1;
 196         const edge_t *e2 = k2;
 197
 198         return ! (e1->n1 == e2->n1   &&   e1->n2 == e2->n2);
 199 }
 200
 201 #define HASH_EDGE(e) (HASH_PTR((e)->n1) ^ HASH_PTR((e)->n2))
 202
 203 static INLINE edge_t *add_edge(set *edges, ir_node *n1, ir_node *n2, int *counter) {
 204         edge_t new_edge;
 205
 206         if (PTR_TO_INT(n1) < PTR_TO_INT(n2)) {
 207                 new_edge.n1 = n1;
 208                 new_edge.n2 = n2;
 209         } else {
 210                 new_edge.n1 = n2;
 211                 new_edge.n2 = n1;
 212         }
 213         (*counter)++;
 214         return set_insert(edges, &new_edge, sizeof(new_edge), HASH_EDGE(&new_edge));
 215 }
 216
 217 static INLINE edge_t *find_edge(set *edges, ir_node *n1, ir_node *n2) {
 218         edge_t new_edge;
 219
 220         if (PTR_TO_INT(n1) < PTR_TO_INT(n2)) {
 221                 new_edge.n1 = n1;
 222                 new_edge.n2 = n2;
 223         } else {
 224                 new_edge.n1 = n2;
 225                 new_edge.n2 = n1;
 226         }
 227         return set_find(edges, &new_edge, sizeof(new_edge), HASH_EDGE(&new_edge));
 228 }
 229
 230 static INLINE void remove_edge(set *edges, ir_node *n1, ir_node *n2, int *counter) {
 231         edge_t new_edge, *e;
 232
 233         if (PTR_TO_INT(n1) < PTR_TO_INT(n2)) {
 234                 new_edge.n1 = n1;
 235                 new_edge.n2 = n2;
 236         } else {
 237                 new_edge.n1 = n2;
 238                 new_edge.n2 = n1;
 239         }
 240         e = set_find(edges, &new_edge, sizeof(new_edge), HASH_EDGE(&new_edge));
 241         if (e) {
 242                 e->n1 = NULL;
 243                 e->n2 = NULL;
 244                 (*counter)--;
 245         }
 246 }
 247
 248 #define pset_foreach(pset, irn)  for(irn=pset_first(pset); irn; irn=pset_next(pset))
 249
 250 /**
 251  * Search for an interference clique and an external node
 252  * with affinity edges to all nodes of the clique.
 253  * At most 1 node of the clique can be colored equally with the external node.
 254  */
 255 static void build_clique_star_cstr(ilp_env_t *ienv) {
 256         affinity_node_t *aff;
 257
 258         /* for each node with affinity edges */
 259         co_gs_foreach_aff_node(ienv->co, aff) {
 260                 struct obstack ob;
 261                 neighb_t *nbr;
 262                 ir_node *center = aff->irn;
 263                 ir_node **nodes;
 264                 set *edges;
 265                 int i, o, n_nodes, n_edges;
 266
 267                 obstack_init(&ob);
 268                 edges = new_set(compare_edge_t, 8);
 269
 270                 /* get all affinity neighbours */
 271                 n_nodes = 0;
 272                 co_gs_foreach_neighb(aff, nbr) {
 273                         obstack_ptr_grow(&ob, nbr->irn);
 274                         ++n_nodes;
 275                 }
 276                 nodes = obstack_finish(&ob);
 277
 278                 /* get all interference edges between these */
 279                 n_edges = 0;
 280                 for (i=0; i<n_nodes; ++i)
 281                         for (o=0; o<i; ++o)
 282                                 if (be_ifg_connected(ienv->co->cenv->ifg, nodes[i], nodes[o]))
 283                                         add_edge(edges, nodes[i], nodes[o], &n_edges);
 284
 285                 /* cover all these interference edges with maximal cliques */
 286                 while (n_edges) {
 287                         edge_t *e;
 288                         pset *clique = pset_new_ptr(8);
 289                         int growed;
 290
 291                         /* get 2 starting nodes to form a clique */
 292                         for (e=set_first(edges); !e->n1; e=set_next(edges))
 293                                 /*nothing*/ ;
 294
 295                         pset_insert_ptr(clique, e->n1);
 296                         pset_insert_ptr(clique, e->n2);
 297                         remove_edge(edges, e->n1, e->n2, &n_edges);
 298
 299                         /* while the clique is growing */
 300                         do {
 301                                 growed = 0;
 302
 303                                 /* search for a candidate to extend the clique */
 304                                 for (i=0; i<n_nodes; ++i) {
 305                                         ir_node *member, *cand = nodes[i];
 306                                         int is_cand;
 307
 308                                         /* if its already in the clique try the next */
 309                                         if (pset_find_ptr(clique, cand))
 310                                                 continue;
 311
 312                                         /* are there all necessary interferences? */
 313                                         is_cand = 1;
 314                                         pset_foreach(clique, member) {
 315                                                 if (!find_edge(edges, cand, member)) {
 316                                                         is_cand = 0;
 317                                                         pset_break(clique);
 318                                                         break;
 319                                                 }
 320                                         }
 321
 322                                         /* now we know if we have a clique extender */
 323                                         if (is_cand) {
 324                                                 /* first remove all covered edges */
 325                                                 pset_foreach(clique, member)
 326                                                         remove_edge(edges, cand, member, &n_edges);
 327
 328                                                 /* insert into clique */
 329                                                 pset_insert_ptr(clique, cand);
 330                                                 growed = 1;
 331                                                 break;
 332                                         }
 333                                 }
 334                         } while (growed);
 335
 336                         /* now the clique is maximal. Finally add the constraint */
 337                         {
 338                                 ir_node *member;
 339                                 int var_idx, cst_idx, center_nr, member_nr;
 340                                 char buf[16];
 341
 342                                 cst_idx = lpp_add_cst(ienv->lp, NULL, lpp_greater, pset_count(clique)-1);
 343                                 center_nr = get_irn_node_nr(center);
 344
 345                                 pset_foreach(clique, member) {
 346                                         member_nr = get_irn_node_nr(member);
 347                                         var_idx = lpp_get_var_idx(ienv->lp, name_cdd_sorted(buf, 'y', center_nr, member_nr));
 348                                         lpp_set_factor_fast(ienv->lp, cst_idx, var_idx, 1.0);
 349                                 }
 350                         }
 351
 352                         del_pset(clique);
 353                 }
 354
 355                 del_set(edges);
 356                 obstack_free(&ob, NULL);
 357         }
 358 }
 359
 360
 361 static void extend_path(ilp_env_t *ienv, pdeq *path, ir_node *irn) {
 362         be_ifg_t *ifg = ienv->co->cenv->ifg;
 363         int i, len;
 364         ir_node **curr_path;
 365         affinity_node_t *aff;
 366         neighb_t *nbr;
 367
 368         /* do not walk backwards or in circles */
 369         if (pdeq_contains(path, irn))
 370                 return;
 371
 372         /* insert the new irn */
 373         pdeq_putr(path, irn);
 374
 375
 376
 377         /* check for forbidden interferences */
 378         len = pdeq_len(path);
 379         curr_path = alloca(len * sizeof(*curr_path));
 380         pdeq_copyl(path, curr_path);
 381
 382         for (i=1; i<len; ++i)
 383                 if (be_ifg_connected(ifg, irn, curr_path[i]))
 384                         goto end;
 385
 386
 387
 388         /* check for terminating interference */
 389         if (be_ifg_connected(ifg, irn, curr_path[0])) {
 390
 391                 /* One node is not a path. */
 392                 /* And a path of length 2 is covered by a clique star constraint. */
 393                 if (len > 2) {
 394                         /* finally build the constraint */
 395                         int cst_idx = lpp_add_cst(ienv->lp, NULL, lpp_greater, 1.0);
 396                         for (i=1; i<len; ++i) {
 397                                 char buf[16];
 398                                 int nr_1    = get_irn_node_nr(curr_path[i-1]);
 399                                 int nr_2    = get_irn_node_nr(curr_path[i]);
 400                                 int var_idx = lpp_get_var_idx(ienv->lp, name_cdd_sorted(buf, 'y', nr_1, nr_2));
 401                                 lpp_set_factor_fast(ienv->lp, cst_idx, var_idx, 1.0);
 402                         }
 403                 }
 404
 405                 /* this path cannot be extended anymore */
 406                 goto end;
 407         }
 408
 409
 410
 411         /* recursively extend the path */
 412         aff = get_affinity_info(ienv->co, irn);
 413         co_gs_foreach_neighb(aff, nbr)
 414                 extend_path(ienv, path, nbr->irn);
 415
 416
 417 end:
 418         /* remove the irn */
 419         pdeq_getr(path);
 420
 421 }
 422
 423 /**
 424  *  Search a path of affinity edges, whose ends are connected
 425  *  by an interference edge and there are no other interference
 426  *  edges in between.
 427  *  Then at least one of these affinity edges must break.
 428  */
 429 static void build_path_cstr(ilp_env_t *ienv) {
 430         affinity_node_t *aff_info;
 431
 432         /* for each node with affinity edges */
 433         co_gs_foreach_aff_node(ienv->co, aff_info) {
 434                 pdeq *path = new_pdeq();
 435
 436                 extend_path(ienv, path, aff_info->irn);
 437
 438                 del_pdeq(path);
 439         }
 440 }
 441
 442 static void ilp2_build(ilp_env_t *ienv) {
 443         local_env_t *lenv = ienv->env;
 444         int lower_bound;
 445
 446         ienv->lp = new_lpp(ienv->co->name, lpp_minimize);
 447         build_coloring_cstr(ienv);
 448         build_interference_cstr(ienv);
 449         build_affinity_cstr(ienv);
 450         build_clique_star_cstr(ienv);
 451         build_path_cstr(ienv);
 452
 453         lower_bound = co_get_lower_bound(ienv->co) - co_get_inevit_copy_costs(ienv->co);
 454         lpp_set_bound(ienv->lp, lower_bound);
 455         lpp_set_time_limit(ienv->lp, lenv->time_limit);
 456 }
 457
 458 static void ilp2_apply(ilp_env_t *ienv) {
 459         local_env_t *lenv = ienv->env;
 460         double *sol;
 461         lpp_sol_state_t state;
 462         int i, count;
 463
 464         /* first check if there was sth. to optimize */
 465         if (lenv->first_x_var >= 0) {
 466
 467                 count = lenv->last_x_var - lenv->first_x_var + 1;
 468                 sol = xmalloc(count * sizeof(sol[0]));
 469                 state = lpp_get_solution(ienv->lp, sol, lenv->first_x_var, lenv->last_x_var);
 470                 if (state != lpp_optimal) {
 471                         printf("WARNING %s: Solution state is not 'optimal': %d\n", ienv->co->name, state);
 472                         assert(state >= lpp_feasible && "The solution should at least be feasible!");
 473                 }
 474
 475                 for (i=0; i<count; ++i) {
 476                         int nodenr, color;
 477                         char var_name[16];
 478
 479                         if (sol[i] > 1-EPSILON) { /* split variable name into components */
 480                                 lpp_get_var_name(ienv->lp, lenv->first_x_var+i, var_name, sizeof(var_name));
 481
 482                                 if (sscanf(var_name, "x_%d_%d", &nodenr, &color) == 2) {
 483                                         ir_node *irn = pmap_get(lenv->nr_2_irn, INT_TO_PTR(nodenr));
 484                                         assert(irn && "This node number must be present in the map");
 485
 486                                         set_irn_col(ienv->co, irn, color);
 487                                 } else
 488                                         assert(0 && "This should be a x-var");
 489                         }
 490                 }
 491         }
 492
 493 #ifdef COPYOPT_STAT
 494         /* TODO adapt to multiple possible ILPs */
 495         copystat_add_ilp_time((int)(1000.0*lpp_get_sol_time(pi->curr_lp)));  //now we have ms
 496         copystat_add_ilp_vars(lpp_get_var_count(pi->curr_lp));
 497         copystat_add_ilp_csts(lpp_get_cst_count(pi->curr_lp));
 498         copystat_add_ilp_iter(lpp_get_iter_cnt(pi->curr_lp));
 499 #endif
 500 }
 501
 502 int co_solve_ilp2(copy_opt_t *co, double time_limit) {
 503         lpp_sol_state_t sol_state;
 504         ilp_env_t *ienv;
 505         local_env_t my;
 506
 507         ASSERT_OU_AVAIL(co); //See build_clique_st
 508         ASSERT_GS_AVAIL(co);
 509
 510         my.time_limit  = time_limit;
 511         my.first_x_var = -1;
 512         my.last_x_var  = -1;
 513         my.nr_2_irn    = pmap_create();
 514         my.dbg         = firm_dbg_register("ir.be.coilp2");
 515         firm_dbg_set_mask(my.dbg, DEBUG_LVL);
 516
 517         ienv = new_ilp_env(co, ilp2_build, ilp2_apply, &my);
 518
 519         sol_state = ilp_go(ienv);
 520
 521         pmap_destroy(my.nr_2_irn);
 522         free_ilp_env(ienv);
 523
 524         return sol_state == lpp_optimal;
 525 }