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

   1 /*
   2  * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
   3  *
   4  * This file is part of libFirm.
   5  *
   6  * This file may be distributed and/or modified under the terms of the
   7  * GNU General Public License version 2 as published by the Free Software
   8  * Foundation and appearing in the file LICENSE.GPL included in the
   9  * packaging of this file.
  10  *
  11  * Licensees holding valid libFirm Professional Edition licenses may use
  12  * this file in accordance with the libFirm Commercial License.
  13  * Agreement provided with the Software.
  14  *
  15  * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
  16  * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  17  * PURPOSE.
  18  */
  19
  20 /**
  21  * @file
  22  * @brief       ILP based copy minimization.
  23  * @author      Daniel Grund
  24  * @date        28.02.2006
  25  *
  26  * ILP formalization using G=(V, E, Q):
  27  *  - 2 class of variables: coloring vars x_ic   and   equal color vars y_ij
  28  *  - Path constraints
  29  *  - Clique-star constraints
  30  *
  31  *
  32  * \min \sum_{ (i,j) \in Q }  w_ij y_ij
  33  *
  34  *     \sum_c x_nc           =  1           n \in N, c \in C
  35  *
  36  *     x_nc                  =  0           n \in N, c \not\in C(n)
  37  *
  38  *     \sum x_nc            <=  1           x_nc \in Clique \in AllCliques,  c \in C
  39  *
  40  *     \sum_{e \in p} y_e   >=  1           p \in P      path constraints
  41  *
  42  *     \sum_{e \in cs} y_e  >= |cs| - 1     cs \in CP    clique-star constraints
  43  *
  44  *     x_nc, y_ij \in N,   w_ij \in R^+
  45  */
  46 #include "config.h"
  47
  48 #include "bitset.h"
  49 #include "raw_bitset.h"
  50 #include "pdeq.h"
  51
  52 #include "util.h"
  53 #include "irgwalk.h"
  54 #include "becopyilp_t.h"
  55 #include "beifg.h"
  56 #include "besched.h"
  57 #include "bemodule.h"
  58
  59 DEBUG_ONLY(static firm_dbg_module_t *dbg;)
  60
  61 typedef struct local_env_t {
  62         int       first_x_var;
  63         int       last_x_var;
  64         unsigned  n_colors;
  65         unsigned *normal_colors;
  66 } local_env_t;
  67
  68 static void make_color_var_name(char *buf, size_t buf_size,
  69                                 const ir_node *node, unsigned color)
  70 {
  71         unsigned node_idx = get_irn_idx(node);
  72         snprintf(buf, buf_size, "x_%u_%u", node_idx, color);
  73 }
  74
  75 static void build_coloring_cstr(ilp_env_t *ienv)
  76 {
  77         local_env_t *lenv   = ienv->env;
  78         be_ifg_t    *ifg    = ienv->co->cenv->ifg;
  79         unsigned     n_regs = arch_register_class_n_regs(ienv->co->cls);
  80         nodes_iter_t iter;
  81         unsigned    *colors;
  82         ir_node     *irn;
  83         char         buf[32];
  84
  85         rbitset_alloca(colors, n_regs);
  86
  87         be_ifg_foreach_node(ifg, &iter, irn) {
  88                 const arch_register_req_t *req;
  89                 unsigned                   col;
  90                 int                        cst_idx;
  91                 unsigned                   curr_node_color;
  92
  93                 if (sr_is_removed(ienv->sr, irn))
  94                         continue;
  95
  96                 req = arch_get_irn_register_req(irn);
  97
  98                 /* get assignable colors */
  99                 if (arch_register_req_is(req, limited)) {
 100                         rbitset_copy(colors, req->limited, n_regs);
 101                 } else {
 102                         rbitset_copy(colors, lenv->normal_colors, n_regs);
 103                 }
 104
 105                 /* add the coloring constraint */
 106                 cst_idx = lpp_add_cst(ienv->lp, NULL, lpp_equal, 1.0);
 107
 108                 curr_node_color = get_irn_col(irn);
 109                 for (col = 0; col < n_regs; ++col) {
 110                         int    var_idx;
 111                         double val;
 112                         if (!rbitset_is_set(colors, col))
 113                                 continue;
 114
 115                         make_color_var_name(buf, sizeof(buf), irn, col);
 116                         var_idx = lpp_add_var(ienv->lp, buf, lpp_binary, 0.0);
 117                         lpp_set_factor_fast(ienv->lp, cst_idx, var_idx, 1);
 118
 119                         val = (col == curr_node_color) ? 1.0 : 0.0;
 120                         lpp_set_start_value(ienv->lp, var_idx, val);
 121
 122                         lenv->last_x_var = var_idx;
 123                         if (lenv->first_x_var == -1)
 124                                 lenv->first_x_var = var_idx;
 125                 }
 126
 127                 /* add register constraint constraints */
 128                 for (col = 0; col < n_regs; ++col) {
 129                         int cst_idx;
 130                         int var_idx;
 131                         if (rbitset_is_set(colors, col))
 132                                 continue;
 133
 134                         make_color_var_name(buf, sizeof(buf), irn, col);
 135                         cst_idx = lpp_add_cst(ienv->lp, NULL, lpp_equal, 0.0);
 136                         var_idx = lpp_add_var(ienv->lp, buf, lpp_binary, 0.0);
 137                         lpp_set_start_value(ienv->lp, var_idx, 0.0);
 138                         lpp_set_factor_fast(ienv->lp, cst_idx, var_idx, 1);
 139
 140                         lenv->last_x_var = var_idx;
 141                 }
 142         }
 143 }
 144
 145 static void build_interference_cstr(ilp_env_t *ienv)
 146 {
 147         lpp_t         *lpp      = ienv->lp;
 148         local_env_t   *lenv     = ienv->env;
 149         be_ifg_t      *ifg      = ienv->co->cenv->ifg;
 150         unsigned       n_colors = lenv->n_colors;
 151         ir_node      **clique   = ALLOCAN(ir_node*, n_colors);
 152         cliques_iter_t iter;
 153         int            size;
 154         unsigned       col;
 155         int            i;
 156
 157         /* for each maximal clique */
 158         be_ifg_foreach_clique(ifg, &iter, clique, &size) {
 159                 unsigned realsize = 0;
 160
 161                 for (i=0; i<size; ++i) {
 162                         if (!sr_is_removed(ienv->sr, clique[i]))
 163                                 ++realsize;
 164                 }
 165
 166                 if (realsize < 2)
 167                         continue;
 168
 169                 /* for all colors */
 170                 for (col=0; col<n_colors; ++col) {
 171                         int cst_idx = lpp_add_cst(lpp, NULL, lpp_less_equal, 1.0);
 172
 173                         /* for each member of this clique */
 174                         for (i=0; i<size; ++i) {
 175                                 ir_node *irn = clique[i];
 176                                 char     buf[32];
 177                                 int      var_idx;
 178
 179                                 if (sr_is_removed(ienv->sr, irn))
 180                                         continue;
 181
 182                                 make_color_var_name(buf, sizeof(buf), irn, col);
 183                                 var_idx = lpp_get_var_idx(lpp, buf);
 184                                 lpp_set_factor_fast(lpp, cst_idx, var_idx, 1);
 185                         }
 186                 }
 187         }
 188 }
 189
 190 static void make_affinity_var_name(char *buf, size_t buf_size,
 191                                    const ir_node *node1, const ir_node *node2)
 192 {
 193         unsigned n1 = get_irn_idx(node1);
 194         unsigned n2 = get_irn_idx(node2);
 195         if (n1 < n2) {
 196                 snprintf(buf, buf_size, "y_%u_%u", n1, n2);
 197         } else {
 198                 snprintf(buf, buf_size, "y_%u_%u", n2, n1);
 199         }
 200 }
 201
 202
 203 /**
 204  * TODO: Remove the dependency of the opt-units data structure
 205  *       by walking over all affinity edges. Graph structure
 206  *       does not provide this walker, yet.
 207  */
 208 static void build_affinity_cstr(ilp_env_t *ienv)
 209 {
 210         local_env_t *lenv     = ienv->env;
 211         unsigned     n_colors = lenv->n_colors;
 212         unit_t      *curr;
 213
 214         /* for all optimization units */
 215         list_for_each_entry(unit_t, curr, &ienv->co->units, units) {
 216                 ir_node *root     = curr->nodes[0];
 217                 unsigned root_col = get_irn_col(root);
 218                 int      i;
 219
 220                 for (i = 1; i < curr->node_count; ++i) {
 221                         ir_node *arg     = curr->nodes[i];
 222                         unsigned arg_col = get_irn_col(arg);
 223                         double   val;
 224                         char     buf[32];
 225                         unsigned col;
 226                         int      y_idx;
 227
 228                         /* add a new affinity variable */
 229                         make_affinity_var_name(buf, sizeof(buf), arg, root);
 230                         y_idx = lpp_add_var(ienv->lp, buf, lpp_binary, curr->costs[i]);
 231                         val   = (root_col == arg_col) ? 0.0 : 1.0;
 232                         lpp_set_start_value(ienv->lp, y_idx, val);
 233
 234                         /* add constraints relating the affinity var to the color vars */
 235                         for (col=0; col<n_colors; ++col) {
 236                                 int cst_idx = lpp_add_cst(ienv->lp, NULL, lpp_less_equal, 0.0);
 237                                 int root_idx;
 238                                 int arg_idx;
 239
 240                                 make_color_var_name(buf, sizeof(buf), root, col);
 241                                 root_idx = lpp_get_var_idx(ienv->lp, buf);
 242                                 make_color_var_name(buf, sizeof(buf), arg, col);
 243                                 arg_idx  = lpp_get_var_idx(ienv->lp, buf);
 244
 245                                 lpp_set_factor_fast(ienv->lp, cst_idx, root_idx,  1.0);
 246                                 lpp_set_factor_fast(ienv->lp, cst_idx, arg_idx,  -1.0);
 247                                 lpp_set_factor_fast(ienv->lp, cst_idx, y_idx, -1.0);
 248                         }
 249                 }
 250         }
 251 }
 252
 253 /**
 254  * Helping stuff for build_clique_star_cstr
 255  */
 256 typedef struct edge_t {
 257         ir_node *n1;
 258         ir_node *n2;
 259 } edge_t;
 260
 261 static int compare_edge_t(const void *k1, const void *k2, size_t size)
 262 {
 263         const edge_t *e1 = k1;
 264         const edge_t *e2 = k2;
 265         (void) size;
 266
 267         return ! (e1->n1 == e2->n1 && e1->n2 == e2->n2);
 268 }
 269
 270 #define HASH_EDGE(e) (hash_irn((e)->n1) ^ hash_irn((e)->n2))
 271
 272 static inline edge_t *add_edge(set *edges, ir_node *n1, ir_node *n2, size_t *counter)
 273 {
 274         edge_t new_edge;
 275
 276         if (PTR_TO_INT(n1) < PTR_TO_INT(n2)) {
 277                 new_edge.n1 = n1;
 278                 new_edge.n2 = n2;
 279         } else {
 280                 new_edge.n1 = n2;
 281                 new_edge.n2 = n1;
 282         }
 283         (*counter)++;
 284         return set_insert(edges, &new_edge, sizeof(new_edge), HASH_EDGE(&new_edge));
 285 }
 286
 287 static inline edge_t *find_edge(set *edges, ir_node *n1, ir_node *n2)
 288 {
 289         edge_t new_edge;
 290
 291         if (PTR_TO_INT(n1) < PTR_TO_INT(n2)) {
 292                 new_edge.n1 = n1;
 293                 new_edge.n2 = n2;
 294         } else {
 295                 new_edge.n1 = n2;
 296                 new_edge.n2 = n1;
 297         }
 298         return set_find(edges, &new_edge, sizeof(new_edge), HASH_EDGE(&new_edge));
 299 }
 300
 301 static inline void remove_edge(set *edges, ir_node *n1, ir_node *n2, size_t *counter)
 302 {
 303         edge_t new_edge, *e;
 304
 305         if (PTR_TO_INT(n1) < PTR_TO_INT(n2)) {
 306                 new_edge.n1 = n1;
 307                 new_edge.n2 = n2;
 308         } else {
 309                 new_edge.n1 = n2;
 310                 new_edge.n2 = n1;
 311         }
 312         e = set_find(edges, &new_edge, sizeof(new_edge), HASH_EDGE(&new_edge));
 313         if (e) {
 314                 e->n1 = NULL;
 315                 e->n2 = NULL;
 316                 (*counter)--;
 317         }
 318 }
 319
 320 #define pset_foreach(pset, irn)  for (irn=pset_first(pset); irn; irn=pset_next(pset))
 321
 322 /**
 323  * Search for an interference clique and an external node
 324  * with affinity edges to all nodes of the clique.
 325  * At most 1 node of the clique can be colored equally with the external node.
 326  */
 327 static void build_clique_star_cstr(ilp_env_t *ienv)
 328 {
 329         affinity_node_t *aff;
 330
 331         /* for each node with affinity edges */
 332         co_gs_foreach_aff_node(ienv->co, aff) {
 333                 struct obstack ob;
 334                 neighb_t *nbr;
 335                 const ir_node *center = aff->irn;
 336                 ir_node **nodes;
 337                 set *edges;
 338                 int i, o, n_nodes;
 339                 size_t n_edges;
 340
 341                 if (arch_irn_is_ignore(aff->irn))
 342                         continue;
 343
 344                 obstack_init(&ob);
 345                 edges = new_set(compare_edge_t, 8);
 346
 347                 /* get all affinity neighbours */
 348                 n_nodes = 0;
 349                 co_gs_foreach_neighb(aff, nbr) {
 350                         if (!arch_irn_is_ignore(nbr->irn)) {
 351                                 obstack_ptr_grow(&ob, nbr->irn);
 352                                 ++n_nodes;
 353                         }
 354                 }
 355                 nodes = obstack_finish(&ob);
 356
 357                 /* get all interference edges between these */
 358                 n_edges = 0;
 359                 for (i=0; i<n_nodes; ++i) {
 360                         for (o=0; o<i; ++o) {
 361                                 if (be_ifg_connected(ienv->co->cenv->ifg, nodes[i], nodes[o]))
 362                                         add_edge(edges, nodes[i], nodes[o], &n_edges);
 363                         }
 364                 }
 365
 366                 /* cover all these interference edges with maximal cliques */
 367                 while (n_edges) {
 368                         edge_t *e;
 369                         pset   *clique = pset_new_ptr(8);
 370                         bool    growed;
 371
 372                         /* get 2 starting nodes to form a clique */
 373                         for (e=set_first(edges); !e->n1; e=set_next(edges)) {
 374                         }
 375
 376                         /* we could be stepped out of the loop before the set iterated to the end */
 377                         set_break(edges);
 378
 379                         pset_insert_ptr(clique, e->n1);
 380                         pset_insert_ptr(clique, e->n2);
 381                         remove_edge(edges, e->n1, e->n2, &n_edges);
 382
 383                         /* while the clique is growing */
 384                         do {
 385                                 growed = false;
 386
 387                                 /* search for a candidate to extend the clique */
 388                                 for (i=0; i<n_nodes; ++i) {
 389                                         ir_node *cand = nodes[i];
 390                                         ir_node *member;
 391                                         bool     is_cand;
 392
 393                                         /* if its already in the clique try the next */
 394                                         if (pset_find_ptr(clique, cand))
 395                                                 continue;
 396
 397                                         /* are there all necessary interferences? */
 398                                         is_cand = true;
 399                                         pset_foreach(clique, member) {
 400                                                 if (!find_edge(edges, cand, member)) {
 401                                                         is_cand = false;
 402                                                         pset_break(clique);
 403                                                         break;
 404                                                 }
 405                                         }
 406
 407                                         /* now we know if we have a clique extender */
 408                                         if (is_cand) {
 409                                                 /* first remove all covered edges */
 410                                                 pset_foreach(clique, member)
 411                                                         remove_edge(edges, cand, member, &n_edges);
 412
 413                                                 /* insert into clique */
 414                                                 pset_insert_ptr(clique, cand);
 415                                                 growed = true;
 416                                                 break;
 417                                         }
 418                                 }
 419                         } while (growed);
 420
 421                         /* now the clique is maximal. Finally add the constraint */
 422                         {
 423                                 ir_node *member;
 424                                 int      var_idx;
 425                                 int      cst_idx;
 426                                 char     buf[32];
 427
 428                                 cst_idx = lpp_add_cst(ienv->lp, NULL, lpp_greater_equal, pset_count(clique)-1);
 429
 430                                 pset_foreach(clique, member) {
 431                                         make_affinity_var_name(buf, sizeof(buf), center, member);
 432                                         var_idx = lpp_get_var_idx(ienv->lp, buf);
 433                                         lpp_set_factor_fast(ienv->lp, cst_idx, var_idx, 1.0);
 434                                 }
 435                         }
 436
 437                         del_pset(clique);
 438                 }
 439
 440                 del_set(edges);
 441                 obstack_free(&ob, NULL);
 442         }
 443 }
 444
 445 static void extend_path(ilp_env_t *ienv, pdeq *path, const ir_node *irn)
 446 {
 447         be_ifg_t *ifg = ienv->co->cenv->ifg;
 448         int i, len;
 449         ir_node **curr_path;
 450         affinity_node_t *aff;
 451         neighb_t *nbr;
 452
 453         /* do not walk backwards or in circles */
 454         if (pdeq_contains(path, irn))
 455                 return;
 456
 457         if (arch_irn_is_ignore(irn))
 458                 return;
 459
 460         /* insert the new irn */
 461         pdeq_putr(path, irn);
 462
 463         /* check for forbidden interferences */
 464         len       = pdeq_len(path);
 465         curr_path = ALLOCAN(ir_node*, len);
 466         pdeq_copyl(path, (const void **)curr_path);
 467
 468         for (i=1; i<len; ++i) {
 469                 if (be_ifg_connected(ifg, irn, curr_path[i]))
 470                         goto end;
 471         }
 472
 473         /* check for terminating interference */
 474         if (be_ifg_connected(ifg, irn, curr_path[0])) {
 475                 /* One node is not a path. */
 476                 /* And a path of length 2 is covered by a clique star constraint. */
 477                 if (len > 2) {
 478                         /* finally build the constraint */
 479                         int cst_idx = lpp_add_cst(ienv->lp, NULL, lpp_greater_equal, 1.0);
 480                         for (i=1; i<len; ++i) {
 481                                 char buf[32];
 482                                 int  var_idx;
 483
 484                                 make_affinity_var_name(buf, sizeof(buf), curr_path[i-1], curr_path[i]);
 485                                 var_idx = lpp_get_var_idx(ienv->lp, buf);
 486                                 lpp_set_factor_fast(ienv->lp, cst_idx, var_idx, 1.0);
 487                         }
 488                 }
 489
 490                 /* this path cannot be extended anymore */
 491                 goto end;
 492         }
 493
 494         /* recursively extend the path */
 495         aff = get_affinity_info(ienv->co, irn);
 496         co_gs_foreach_neighb(aff, nbr) {
 497                 extend_path(ienv, path, nbr->irn);
 498         }
 499
 500 end:
 501         /* remove the irn */
 502         pdeq_getr(path);
 503 }
 504
 505 /**
 506  *  Search a path of affinity edges, whose ends are connected
 507  *  by an interference edge and there are no other interference
 508  *  edges in between.
 509  *  Then at least one of these affinity edges must break.
 510  */
 511 static void build_path_cstr(ilp_env_t *ienv)
 512 {
 513         affinity_node_t *aff_info;
 514
 515         /* for each node with affinity edges */
 516         co_gs_foreach_aff_node(ienv->co, aff_info) {
 517                 pdeq *path = new_pdeq();
 518
 519                 extend_path(ienv, path, aff_info->irn);
 520
 521                 del_pdeq(path);
 522         }
 523 }
 524
 525 static void ilp2_build(ilp_env_t *ienv)
 526 {
 527         int lower_bound;
 528
 529         ienv->lp = lpp_new(ienv->co->name, lpp_minimize);
 530         build_coloring_cstr(ienv);
 531         build_interference_cstr(ienv);
 532         build_affinity_cstr(ienv);
 533         build_clique_star_cstr(ienv);
 534         build_path_cstr(ienv);
 535
 536         lower_bound = co_get_lower_bound(ienv->co) - co_get_inevit_copy_costs(ienv->co);
 537         lpp_set_bound(ienv->lp, lower_bound);
 538 }
 539
 540 static void ilp2_apply(ilp_env_t *ienv)
 541 {
 542         local_env_t *lenv = ienv->env;
 543         ir_graph    *irg  = ienv->co->irg;
 544
 545         /* first check if there was sth. to optimize */
 546         if (lenv->first_x_var >= 0) {
 547                 int              count = lenv->last_x_var - lenv->first_x_var + 1;
 548                 double          *sol   = XMALLOCN(double, count);
 549                 lpp_sol_state_t  state = lpp_get_solution(ienv->lp, sol, lenv->first_x_var, lenv->last_x_var);
 550                 int              i;
 551
 552                 if (state != lpp_optimal) {
 553                         printf("WARNING %s: Solution state is not 'optimal': %d\n",
 554                                ienv->co->name, (int)state);
 555                         if (state < lpp_feasible) {
 556                                 panic("Copy coalescing solution not feasible!");
 557                         }
 558                 }
 559
 560                 for (i=0; i<count; ++i) {
 561                         unsigned nodenr;
 562                         unsigned color;
 563                         char     var_name[32];
 564                         if (sol[i] <= 1-EPSILON)
 565                                 continue;
 566                         /* split variable name into components */
 567                         lpp_get_var_name(ienv->lp, lenv->first_x_var+i, var_name, sizeof(var_name));
 568
 569                         if (sscanf(var_name, "x_%u_%u", &nodenr, &color) == 2) {
 570                                 ir_node *irn = get_idx_irn(irg, nodenr);
 571                                 set_irn_col(ienv->co->cls, irn, color);
 572                         } else {
 573                                 panic("This should be a x-var");
 574                         }
 575                 }
 576
 577                 xfree(sol);
 578         }
 579
 580 #ifdef COPYOPT_STAT
 581         /* TODO adapt to multiple possible ILPs */
 582         copystat_add_ilp_time((int)(1000.0*lpp_get_sol_time(pi->curr_lp)));  //now we have ms
 583         copystat_add_ilp_vars(lpp_get_var_count(pi->curr_lp));
 584         copystat_add_ilp_csts(lpp_get_cst_count(pi->curr_lp));
 585         copystat_add_ilp_iter(lpp_get_iter_cnt(pi->curr_lp));
 586 #endif
 587 }
 588
 589 /**
 590  * Solves the problem using mixed integer programming
 591  * @returns 1 iff solution state was optimal
 592  * Uses the OU and the GRAPH data structure
 593  * Dependency of the OU structure can be removed
 594  */
 595 static int co_solve_ilp2(copy_opt_t *co)
 596 {
 597         unsigned        n_regs = arch_register_class_n_regs(co->cls);
 598         lpp_sol_state_t sol_state;
 599         ilp_env_t      *ienv;
 600         local_env_t     my;
 601
 602         ASSERT_OU_AVAIL(co); //See build_clique_st
 603         ASSERT_GS_AVAIL(co);
 604
 605         my.first_x_var = -1;
 606         my.last_x_var  = -1;
 607         FIRM_DBG_REGISTER(dbg, "firm.be.coilp2");
 608
 609         rbitset_alloca(my.normal_colors, n_regs);
 610         be_set_allocatable_regs(co->irg, co->cls, my.normal_colors);
 611         my.n_colors = rbitset_popcount(my.normal_colors, n_regs);
 612
 613         ienv = new_ilp_env(co, ilp2_build, ilp2_apply, &my);
 614
 615         sol_state = ilp_go(ienv);
 616
 617         free_ilp_env(ienv);
 618
 619         return sol_state == lpp_optimal;
 620 }
 621
 622 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_copyilp2)
 623 void be_init_copyilp2(void)
 624 {
 625         static co_algo_info copyheur = {
 626                 co_solve_ilp2, 1
 627         };
 628
 629         be_register_copyopt("ilp", &copyheur);
 630 }