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