nsz Git - libfirm/blob - ir/be/bessadestr.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       Performs SSA-Destruction.
  23  * @author      Daniel Grund
  24  * @date        25.05.2005
  25  * @version     $Id$
  26  */
  27 #include "config.h"
  28
  29 #include "bessadestr.h"
  30
  31 #include "debug.h"
  32 #include "set.h"
  33 #include "pmap.h"
  34 #include "irnode_t.h"
  35 #include "ircons_t.h"
  36 #include "iredges_t.h"
  37 #include "irgwalk.h"
  38 #include "irgmod.h"
  39 #include "irdump.h"
  40 #include "irprintf.h"
  41
  42 #include "be_t.h"
  43 #include "beutil.h"
  44 #include "bechordal_t.h"
  45 #include "bearch.h"
  46 #include "belive_t.h"
  47 #include "benode.h"
  48 #include "besched.h"
  49 #include "bestatevent.h"
  50 #include "beirg.h"
  51 #include "beintlive_t.h"
  52
  53 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
  54
  55 static void clear_link(ir_node *irn, void *data)
  56 {
  57         (void) data;
  58         set_irn_link(irn, NULL);
  59 }
  60
  61 /**
  62  * For each block build a linked list of phis that
  63  *  - are in that block
  64  *  - have the current register class
  65  * The list is rooted at get_irn_link(BB).
  66  */
  67 static void collect_phis_walker(ir_node *irn, void *data)
  68 {
  69         be_chordal_env_t *env = (be_chordal_env_t*)data;
  70         if (is_Phi(irn) && chordal_has_class(env, irn)) {
  71                 ir_node *bl = get_nodes_block(irn);
  72                 set_irn_link(irn, get_irn_link(bl));
  73                 set_irn_link(bl, irn);
  74         }
  75 }
  76
  77 /**
  78  * This struct represents a Proj for a Perm.
  79  * It records the argument in the Perm and the corresponding Proj of the
  80  * Perm.
  81  */
  82 typedef struct {
  83         ir_node *arg;  /**< The phi argument to make the Proj for. */
  84         int pos;       /**< The proj number the Proj will get.
  85                                                                          This also denotes the position of @p arg
  86                                                                          in the in array of the Perm. */
  87         ir_node *proj; /**< The proj created for @p arg. */
  88 } perm_proj_t;
  89
  90 static int cmp_perm_proj(const void *a, const void *b, size_t n)
  91 {
  92         const perm_proj_t *p = (const perm_proj_t*)a;
  93         const perm_proj_t *q = (const perm_proj_t*)b;
  94         (void) n;
  95
  96         return !(p->arg == q->arg);
  97 }
  98
  99 typedef struct insert_all_perms_env_t {
 100         be_chordal_env_t *chordal_env;
 101         pmap *perm_map;
 102 } insert_all_perms_env_t;
 103
 104 /**
 105  * Insert Perms in all predecessors of a block containing a phi
 106  */
 107 static void insert_all_perms_walker(ir_node *bl, void *data)
 108 {
 109         insert_all_perms_env_t *env = (insert_all_perms_env_t*)data;
 110         be_chordal_env_t *chordal_env = env->chordal_env;
 111         pmap *perm_map = env->perm_map;
 112         be_lv_t *lv = be_get_irg_liveness(chordal_env->irg);
 113         int i, n;
 114
 115         assert(is_Block(bl));
 116
 117         /* If the link flag is NULL, this block has no phis. */
 118         if (!get_irn_link(bl))
 119                 return;
 120
 121         /* Look at all predecessors of the phi block */
 122         for (i = 0, n = get_irn_arity(bl); i < n; ++i) {
 123                 ir_node *phi, *perm, *insert_after, **in;
 124                 perm_proj_t *pp;
 125                 set *arg_set     = new_set(cmp_perm_proj, chordal_env->cls->n_regs);
 126                 ir_node *pred_bl = get_Block_cfgpred_block(bl, i);
 127                 int n_projs      = 0;
 128
 129                 assert(!pmap_contains(perm_map, pred_bl) && "Already permed that block");
 130
 131                 /*
 132                  * Note that all phis in the list are in the same
 133                  * register class by construction.
 134                  */
 135                 for (phi = (ir_node*)get_irn_link(bl); phi != NULL;
 136                      phi = (ir_node*)get_irn_link(phi)) {
 137                         ir_node                   *arg = get_irn_n(phi, i);
 138                         unsigned                   hash;
 139                         perm_proj_t                templ;
 140
 141                         hash = hash_irn(arg);
 142                         templ.arg  = arg;
 143                         pp         = (perm_proj_t*)set_find(arg_set, &templ, sizeof(templ), hash);
 144
 145                         /*
 146                          * If a proj_perm_t entry has not been made in the argument set,
 147                          * create one. The only restriction is, that the phi argument
 148                          * may not be live in at the current block, since this argument
 149                          * interferes with the phi and must thus not be member of a
 150                          * Perm. A copy will be inserted for this argument later on.
 151                          */
 152                         if (!pp && !be_is_live_in(lv, bl, arg)) {
 153                                 templ.pos = n_projs++;
 154                                 set_insert(arg_set, &templ, sizeof(templ), hash);
 155                         }
 156                 }
 157
 158
 159                 if (n_projs) {
 160                         /*
 161                          * Create a new Perm with the arguments just collected
 162                          * above in the arg_set and insert it into the schedule.
 163                          */
 164                         in = XMALLOCN(ir_node*, n_projs);
 165                         foreach_set(arg_set, perm_proj_t*, pp) {
 166                                 in[pp->pos] = pp->arg;
 167                         }
 168
 169                         perm = be_new_Perm(chordal_env->cls, pred_bl, n_projs, in);
 170                         be_stat_ev("phi_perm", n_projs);
 171
 172                         insert_after = pred_bl;
 173                         do {
 174                                 insert_after = sched_prev(insert_after);
 175                         } while (is_cfop(insert_after));
 176                         sched_add_after(insert_after, perm);
 177
 178                         /*
 179                          * Make the Projs for the Perm and insert into schedule.
 180                          * Register allocation is copied from the former phi
 181                          * arguments to the projs (new phi arguments).
 182                          */
 183                         insert_after = perm;
 184                         foreach_set(arg_set, perm_proj_t*, pp) {
 185                                 ir_node *proj = new_r_Proj(perm, get_irn_mode(pp->arg), pp->pos);
 186                                 pp->proj = proj;
 187                                 assert(arch_get_irn_register(pp->arg));
 188                                 arch_set_irn_register(proj, arch_get_irn_register(pp->arg));
 189                                 insert_after = proj;
 190                                 DBG((dbg, LEVEL_2, "Copy register assignment %s from %+F to %+F\n", arch_get_irn_register(pp->arg)->name, pp->arg, pp->proj));
 191                         }
 192
 193                         /*
 194                          * Set the phi nodes to their new arguments: The Projs of the Perm
 195                          */
 196                         for (phi = (ir_node*)get_irn_link(bl); phi != NULL;
 197                              phi = (ir_node*)get_irn_link(phi)) {
 198                                 perm_proj_t templ;
 199
 200                                 templ.arg = get_irn_n(phi, i);
 201                                 pp        = (perm_proj_t*)set_find(arg_set, &templ, sizeof(templ), hash_irn(templ.arg));
 202
 203                                 /* If not found, it was an interfering argument */
 204                                 if (pp) {
 205                                         set_irn_n(phi, i, pp->proj);
 206                                         be_liveness_introduce(lv, pp->proj);
 207                                 }
 208                         }
 209
 210                         /* update the liveness of the Perm's operands. It might be changed. */
 211                         {
 212                                 int i;
 213                                 for (i = 0; i < n_projs; ++i)
 214                                         be_liveness_update(lv, in[i]);
 215                         }
 216                         free(in);
 217
 218                         /* register in perm map */
 219                         pmap_insert(perm_map, pred_bl, perm);
 220                 }
 221
 222                 del_set(arg_set);
 223         }
 224 }
 225
 226 #define is_pinned(irn) (get_irn_link(irn))
 227 #define get_pinning_block(irn) ((ir_node *)get_irn_link(irn))
 228 #define pin_irn(irn, lock) (set_irn_link(irn, lock))
 229
 230 /**
 231  * Adjusts the register allocation for the (new) phi-operands
 232  * and insert duplicates iff necessary.
 233  */
 234 static void set_regs_or_place_dupls_walker(ir_node *bl, void *data)
 235 {
 236         be_chordal_env_t *chordal_env = (be_chordal_env_t*)data;
 237         be_lv_t *lv = be_get_irg_liveness(chordal_env->irg);
 238         ir_node *phi;
 239
 240         /* Consider all phis of this block */
 241         for (phi = (ir_node*)get_irn_link(bl); phi != NULL;
 242              phi = (ir_node*)get_irn_link(phi)) {
 243                 ir_node                     *phi_block = get_nodes_block(phi);
 244                 const arch_register_t       *phi_reg   = arch_get_irn_register(phi);
 245                 int                          max;
 246                 int                          i;
 247
 248                 assert(is_Phi(phi) && "Can only handle phi-destruction :)");
 249
 250                 /* process all arguments of the phi */
 251                 for (i = 0, max = get_irn_arity(phi); i < max; ++i) {
 252                         ir_node                   *arg = get_irn_n(phi, i);
 253                         const arch_register_t     *arg_reg;
 254                         ir_node                   *arg_block;
 255
 256                         arg_block = get_Block_cfgpred_block(phi_block, i);
 257                         arg_reg   = arch_get_irn_register(arg);
 258
 259                         assert(arg_reg && "Register must be set while placing perms");
 260
 261                         DBG((dbg, LEVEL_1, "  for %+F(%s) -- %+F(%s)\n", phi, phi_reg->name, arg, arg_reg->name));
 262
 263                         if (phi_reg == arg_reg
 264                                         || (arg_reg->type & arch_register_type_joker)
 265                                         || (arg_reg->type & arch_register_type_virtual)) {
 266                                 /* Phi and arg have the same register, so pin and continue */
 267                                 pin_irn(arg, phi_block);
 268                                 DBG((dbg, LEVEL_1, "      arg has same reg: pin %+F(%s)\n", arg, arch_get_irn_register(arg)->name));
 269                                 continue;
 270                         }
 271
 272                         if (be_values_interfere(lv, phi, arg)) {
 273                                 ir_node *schedpoint;
 274
 275                                 /*
 276                                         Insert a duplicate in arguments block,
 277                                         make it the new phi arg,
 278                                         set its register,
 279                                         insert it into schedule,
 280                                         pin it
 281                                 */
 282                                 ir_node *dupl = be_new_Copy(arg_block, arg);
 283
 284                                 set_irn_n(phi, i, dupl);
 285                                 arch_set_irn_register(dupl, phi_reg);
 286                                 schedpoint = arg_block;
 287                                 do {
 288                                         schedpoint = sched_prev(schedpoint);
 289                                 } while (is_cfop(schedpoint));
 290                                 sched_add_after(schedpoint, dupl);
 291                                 pin_irn(dupl, phi_block);
 292                                 be_liveness_introduce(lv, dupl);
 293                                 be_liveness_update(lv, arg);
 294                                 DBG((dbg, LEVEL_1, "    they do interfere: insert %+F(%s)\n", dupl, arch_get_irn_register(dupl)->name));
 295                                 continue; /* with next argument */
 296                         }
 297
 298                         DBG((dbg, LEVEL_1, "    they do not interfere\n"));
 299                         assert(is_Proj(arg));
 300                         /*
 301                                 First check if there is an other phi
 302                                 - in the same block
 303                                 - having arg at the current pos in its arg-list
 304                                 - having the same color as arg
 305
 306                                 If found, then pin the arg (for that phi)
 307                         */
 308                         if (! is_pinned(arg)) {
 309                                 ir_node *other_phi;
 310
 311                                 DBG((dbg, LEVEL_1, "      searching for phi with same arg having args register\n"));
 312
 313                                 for (other_phi = (ir_node*)get_irn_link(phi_block);
 314                                      other_phi != NULL;
 315                                      other_phi = (ir_node*)get_irn_link(other_phi)) {
 316
 317                                         assert(is_Phi(other_phi)                               &&
 318                                                 get_nodes_block(phi) == get_nodes_block(other_phi) &&
 319                                                 "link fields are screwed up");
 320
 321                                         if (get_irn_n(other_phi, i) == arg && arch_get_irn_register(other_phi) == arg_reg) {
 322                                                 DBG((dbg, LEVEL_1, "        found %+F(%s)\n", other_phi, arch_get_irn_register(other_phi)->name));
 323                                                 pin_irn(arg, phi_block);
 324                                                 break;
 325                                         }
 326                                 }
 327                         }
 328
 329                         if (is_pinned(arg)) {
 330                                 /*
 331                                         Insert a duplicate of the original value in arguments block,
 332                                         make it the new phi arg,
 333                                         set its register,
 334                                         insert it into schedule,
 335                                         pin it
 336                                 */
 337                                 ir_node *perm = get_Proj_pred(arg);
 338                                 ir_node *dupl = be_new_Copy(arg_block, arg);
 339                                 ir_node *ins;
 340
 341                                 set_irn_n(phi, i, dupl);
 342                                 arch_set_irn_register(dupl, phi_reg);
 343                                 /* skip the Perm's Projs and insert the copies behind. */
 344                                 for (ins = sched_next(perm); is_Proj(ins); ins = sched_next(ins)) {
 345                                 }
 346                                 sched_add_before(ins, dupl);
 347                                 pin_irn(dupl, phi_block);
 348                                 be_liveness_introduce(lv, dupl);
 349                                 be_liveness_update(lv, arg);
 350                                 DBG((dbg, LEVEL_1, "      arg is pinned: insert %+F(%s)\n", dupl, arch_get_irn_register(dupl)->name));
 351                         } else {
 352                                 /*
 353                                         No other phi has the same color (else arg would have been pinned),
 354                                         so just set the register and pin
 355                                 */
 356                                 arch_set_irn_register(arg, phi_reg);
 357                                 pin_irn(arg, phi_block);
 358                                 DBG((dbg, LEVEL_1, "      arg is not pinned: so pin %+F(%s)\n", arg, arch_get_irn_register(arg)->name));
 359                         }
 360                 }
 361         }
 362 }
 363
 364 void be_ssa_destruction(be_chordal_env_t *chordal_env)
 365 {
 366         insert_all_perms_env_t insert_perms_env;
 367         pmap     *perm_map = pmap_create();
 368         ir_graph *irg      = chordal_env->irg;
 369         be_lv_t  *lv       = be_assure_liveness(irg);
 370
 371         FIRM_DBG_REGISTER(dbg, "ir.be.ssadestr");
 372
 373         be_liveness_invalidate(lv);
 374
 375         /* create a map for fast lookup of perms: block --> perm */
 376         irg_walk_graph(irg, clear_link, collect_phis_walker, chordal_env);
 377
 378         DBG((dbg, LEVEL_1, "Placing perms...\n"));
 379         insert_perms_env.chordal_env = chordal_env;
 380         insert_perms_env.perm_map = perm_map;
 381         irg_block_walk_graph(irg, insert_all_perms_walker, NULL, &insert_perms_env);
 382
 383         // Matze: really needed here?
 384         // Sebastian: Yes. the walker function uses interference.
 385         be_liveness_invalidate(lv);
 386
 387         if (chordal_env->opts->dump_flags & BE_CH_DUMP_SSADESTR)
 388                 dump_ir_graph(irg, "ssa_destr_perms_placed");
 389
 390         be_liveness_assure_chk(lv);
 391
 392         DBG((dbg, LEVEL_1, "Setting regs and placing dupls...\n"));
 393         irg_block_walk_graph(irg, set_regs_or_place_dupls_walker, NULL, chordal_env);
 394
 395         /* TODO: unfortunately updating doesn't work yet. */
 396         be_liveness_invalidate(lv);
 397
 398         if (chordal_env->opts->dump_flags & BE_CH_DUMP_SSADESTR)
 399                 dump_ir_graph(irg, "ssa_destr_regs_set");
 400
 401         pmap_destroy(perm_map);
 402 }
 403
 404 static void ssa_destruction_check_walker(ir_node *bl, void *data)
 405 {
 406         ir_node *phi;
 407         int i, max;
 408         (void)data;
 409
 410         for (phi = (ir_node*)get_irn_link(bl); phi != NULL;
 411              phi = (ir_node*)get_irn_link(phi)) {
 412                 const arch_register_t *phi_reg, *arg_reg;
 413
 414                 phi_reg = arch_get_irn_register(phi);
 415                 /* iterate over all args of phi */
 416                 for (i = 0, max = get_irn_arity(phi); i < max; ++i) {
 417                         ir_node                   *arg = get_irn_n(phi, i);
 418                         const arch_register_req_t *req = arch_get_irn_register_req(arg);
 419
 420                         if (req->type & arch_register_req_type_ignore)
 421                                 continue;
 422
 423                         arg_reg = arch_get_irn_register(arg);
 424
 425                         if (phi_reg != arg_reg) {
 426                                 DBG((dbg, 0, "Error: Registers of %+F and %+F differ: %s %s\n", phi, arg, phi_reg->name, arg_reg->name));
 427                                 assert(0);
 428                         }
 429
 430                         if (! is_pinned(arg)) {
 431                                 DBG((dbg, 0, "Warning: Phi argument %+F is not pinned.\n", arg));
 432                                 assert(0);
 433                         }
 434                 }
 435         }
 436 }
 437
 438 void be_ssa_destruction_check(be_chordal_env_t *chordal_env)
 439 {
 440         irg_block_walk_graph(chordal_env->irg, ssa_destruction_check_walker, NULL, NULL);
 441 }