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

   1 /*
   2  * This file is part of libFirm.
   3  * Copyright (C) 2012 University of Karlsruhe.
   4  */
   5
   6 /**
   7  * @file
   8  * @brief       Performs SSA-Destruction.
   9  * @author      Daniel Grund
  10  * @date        25.05.2005
  11  */
  12 #include "config.h"
  13
  14 #include "bessadestr.h"
  15
  16 #include "debug.h"
  17 #include "set.h"
  18 #include "pmap.h"
  19 #include "irnode_t.h"
  20 #include "ircons_t.h"
  21 #include "iredges_t.h"
  22 #include "irgwalk.h"
  23 #include "irgmod.h"
  24 #include "irdump.h"
  25 #include "irprintf.h"
  26
  27 #include "be_t.h"
  28 #include "beutil.h"
  29 #include "bechordal_t.h"
  30 #include "bearch.h"
  31 #include "belive_t.h"
  32 #include "benode.h"
  33 #include "besched.h"
  34 #include "statev_t.h"
  35 #include "beirg.h"
  36 #include "beintlive_t.h"
  37 #include "bespillutil.h"
  38
  39 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
  40
  41 static void clear_link(ir_node *irn, void *data)
  42 {
  43         (void) data;
  44         set_irn_link(irn, NULL);
  45 }
  46
  47 /**
  48  * For each block build a linked list of phis that
  49  *  - are in that block
  50  *  - have the current register class
  51  * The list is rooted at get_irn_link(BB).
  52  */
  53 static void collect_phis_walker(ir_node *irn, void *data)
  54 {
  55         be_chordal_env_t *env = (be_chordal_env_t*)data;
  56         if (is_Phi(irn) && arch_irn_consider_in_reg_alloc(env->cls, irn)) {
  57                 ir_node *bl = get_nodes_block(irn);
  58                 set_irn_link(irn, get_irn_link(bl));
  59                 set_irn_link(bl, irn);
  60         }
  61 }
  62
  63 /**
  64  * This struct represents a Proj for a Perm.
  65  * It records the argument in the Perm and the corresponding Proj of the
  66  * Perm.
  67  */
  68 typedef struct {
  69         ir_node *arg;  /**< The phi argument to make the Proj for. */
  70         int pos;       /**< The proj number the Proj will get.
  71                                                                          This also denotes the position of @p arg
  72                                                                          in the in array of the Perm. */
  73         ir_node *proj; /**< The proj created for @p arg. */
  74 } perm_proj_t;
  75
  76 static int cmp_perm_proj(const void *a, const void *b, size_t n)
  77 {
  78         const perm_proj_t *p = (const perm_proj_t*)a;
  79         const perm_proj_t *q = (const perm_proj_t*)b;
  80         (void) n;
  81
  82         return !(p->arg == q->arg);
  83 }
  84
  85 /**
  86  * Insert Perms in all predecessors of a block containing a phi
  87  */
  88 static void insert_all_perms_walker(ir_node *bl, void *data)
  89 {
  90         be_chordal_env_t *const chordal_env = (be_chordal_env_t*)data;
  91         be_lv_t *lv = be_get_irg_liveness(chordal_env->irg);
  92         int i, n;
  93
  94         assert(is_Block(bl));
  95
  96         /* If the link flag is NULL, this block has no phis. */
  97         if (!get_irn_link(bl))
  98                 return;
  99
 100         /* Look at all predecessors of the phi block */
 101         for (i = 0, n = get_irn_arity(bl); i < n; ++i) {
 102                 ir_node *phi, *perm, **in;
 103                 set *arg_set     = new_set(cmp_perm_proj, chordal_env->cls->n_regs);
 104                 ir_node *pred_bl = get_Block_cfgpred_block(bl, i);
 105                 int n_projs      = 0;
 106
 107                 /*
 108                  * Note that all phis in the list are in the same
 109                  * register class by construction.
 110                  */
 111                 for (phi = (ir_node*)get_irn_link(bl); phi != NULL;
 112                      phi = (ir_node*)get_irn_link(phi)) {
 113                         ir_node                   *arg = get_irn_n(phi, i);
 114                         unsigned                   hash;
 115                         perm_proj_t                templ;
 116
 117                         hash = hash_irn(arg);
 118                         templ.arg  = arg;
 119                         perm_proj_t *const pp = set_find(perm_proj_t, arg_set, &templ, sizeof(templ), hash);
 120
 121                         /*
 122                          * If a proj_perm_t entry has not been made in the argument set,
 123                          * create one. The only restriction is, that the phi argument
 124                          * may not be live in at the current block, since this argument
 125                          * interferes with the phi and must thus not be member of a
 126                          * Perm. A copy will be inserted for this argument later on.
 127                          */
 128                         if (!pp && !be_is_live_in(lv, bl, arg)) {
 129                                 templ.pos = n_projs++;
 130                                 (void)set_insert(perm_proj_t, arg_set, &templ, sizeof(templ), hash);
 131                         }
 132                 }
 133
 134
 135                 if (n_projs) {
 136                         /*
 137                          * Create a new Perm with the arguments just collected
 138                          * above in the arg_set and insert it into the schedule.
 139                          */
 140                         in = XMALLOCN(ir_node*, n_projs);
 141                         foreach_set(arg_set, perm_proj_t, pp) {
 142                                 in[pp->pos] = pp->arg;
 143                         }
 144
 145                         perm = be_new_Perm(chordal_env->cls, pred_bl, n_projs, in);
 146                         stat_ev_int("phi_perm", n_projs);
 147
 148                         ir_node *const schedpoint = be_get_end_of_block_insertion_point(pred_bl);
 149                         sched_add_before(schedpoint, perm);
 150
 151                         /*
 152                          * Make the Projs for the Perm and insert into schedule.
 153                          * Register allocation is copied from the former phi
 154                          * arguments to the projs (new phi arguments).
 155                          */
 156                         foreach_set(arg_set, perm_proj_t, pp) {
 157                                 ir_node *proj = new_r_Proj(perm, get_irn_mode(pp->arg), pp->pos);
 158                                 pp->proj = proj;
 159                                 assert(arch_get_irn_register(pp->arg));
 160                                 arch_set_irn_register(proj, arch_get_irn_register(pp->arg));
 161                                 DBG((dbg, LEVEL_2, "Copy register assignment %s from %+F to %+F\n", arch_get_irn_register(pp->arg)->name, pp->arg, pp->proj));
 162                         }
 163
 164                         /*
 165                          * Set the phi nodes to their new arguments: The Projs of the Perm
 166                          */
 167                         for (phi = (ir_node*)get_irn_link(bl); phi != NULL;
 168                              phi = (ir_node*)get_irn_link(phi)) {
 169                                 perm_proj_t templ;
 170
 171                                 templ.arg = get_irn_n(phi, i);
 172                                 perm_proj_t *const pp = set_find(perm_proj_t, arg_set, &templ, sizeof(templ), hash_irn(templ.arg));
 173
 174                                 /* If not found, it was an interfering argument */
 175                                 if (pp) {
 176                                         set_irn_n(phi, i, pp->proj);
 177                                         be_liveness_introduce(lv, pp->proj);
 178                                 }
 179                         }
 180
 181                         /* update the liveness of the Perm's operands. It might be changed. */
 182                         {
 183                                 int i;
 184                                 for (i = 0; i < n_projs; ++i)
 185                                         be_liveness_update(lv, in[i]);
 186                         }
 187                         free(in);
 188                 }
 189
 190                 del_set(arg_set);
 191         }
 192 }
 193
 194 #define is_pinned(irn) (get_irn_link(irn))
 195 #define get_pinning_block(irn) ((ir_node *)get_irn_link(irn))
 196 #define pin_irn(irn, lock) (set_irn_link(irn, lock))
 197
 198 /**
 199  * Adjusts the register allocation for the (new) phi-operands
 200  * and insert duplicates iff necessary.
 201  */
 202 static void set_regs_or_place_dupls_walker(ir_node *bl, void *data)
 203 {
 204         be_chordal_env_t *chordal_env = (be_chordal_env_t*)data;
 205         be_lv_t *lv = be_get_irg_liveness(chordal_env->irg);
 206         ir_node *phi;
 207
 208         /* Consider all phis of this block */
 209         for (phi = (ir_node*)get_irn_link(bl); phi != NULL;
 210              phi = (ir_node*)get_irn_link(phi)) {
 211                 ir_node                     *phi_block = get_nodes_block(phi);
 212                 const arch_register_t       *phi_reg   = arch_get_irn_register(phi);
 213                 int                          max;
 214                 int                          i;
 215
 216                 assert(is_Phi(phi) && "Can only handle phi-destruction :)");
 217
 218                 /* process all arguments of the phi */
 219                 for (i = 0, max = get_irn_arity(phi); i < max; ++i) {
 220                         ir_node                   *arg = get_irn_n(phi, i);
 221                         const arch_register_t     *arg_reg;
 222                         ir_node                   *arg_block;
 223
 224                         arg_block = get_Block_cfgpred_block(phi_block, i);
 225                         arg_reg   = arch_get_irn_register(arg);
 226
 227                         assert(arg_reg && "Register must be set while placing perms");
 228
 229                         DBG((dbg, LEVEL_1, "  for %+F(%s) -- %+F(%s)\n", phi, phi_reg->name, arg, arg_reg->name));
 230
 231                         if (phi_reg == arg_reg
 232                                         || (arg_reg->type & arch_register_type_virtual)) {
 233                                 /* Phi and arg have the same register, so pin and continue */
 234                                 pin_irn(arg, phi_block);
 235                                 DBG((dbg, LEVEL_1, "      arg has same reg: pin %+F(%s)\n", arg, arch_get_irn_register(arg)->name));
 236                                 continue;
 237                         }
 238
 239                         if (be_values_interfere(lv, phi, arg)) {
 240                                 /*
 241                                         Insert a duplicate in arguments block,
 242                                         make it the new phi arg,
 243                                         set its register,
 244                                         insert it into schedule,
 245                                         pin it
 246                                 */
 247                                 ir_node *dupl = be_new_Copy(arg_block, arg);
 248
 249                                 set_irn_n(phi, i, dupl);
 250                                 arch_set_irn_register(dupl, phi_reg);
 251                                 ir_node *const schedpoint = be_get_end_of_block_insertion_point(arg_block);
 252                                 sched_add_before(schedpoint, dupl);
 253                                 pin_irn(dupl, phi_block);
 254                                 be_liveness_introduce(lv, dupl);
 255                                 be_liveness_update(lv, arg);
 256                                 DBG((dbg, LEVEL_1, "    they do interfere: insert %+F(%s)\n", dupl, arch_get_irn_register(dupl)->name));
 257                                 continue; /* with next argument */
 258                         }
 259
 260                         DBG((dbg, LEVEL_1, "    they do not interfere\n"));
 261                         assert(is_Proj(arg));
 262                         /*
 263                                 First check if there is an other phi
 264                                 - in the same block
 265                                 - having arg at the current pos in its arg-list
 266                                 - having the same color as arg
 267
 268                                 If found, then pin the arg (for that phi)
 269                         */
 270                         if (! is_pinned(arg)) {
 271                                 ir_node *other_phi;
 272
 273                                 DBG((dbg, LEVEL_1, "      searching for phi with same arg having args register\n"));
 274
 275                                 for (other_phi = (ir_node*)get_irn_link(phi_block);
 276                                      other_phi != NULL;
 277                                      other_phi = (ir_node*)get_irn_link(other_phi)) {
 278
 279                                         assert(is_Phi(other_phi)                               &&
 280                                                 get_nodes_block(phi) == get_nodes_block(other_phi) &&
 281                                                 "link fields are screwed up");
 282
 283                                         if (get_irn_n(other_phi, i) == arg && arch_get_irn_register(other_phi) == arg_reg) {
 284                                                 DBG((dbg, LEVEL_1, "        found %+F(%s)\n", other_phi, arch_get_irn_register(other_phi)->name));
 285                                                 pin_irn(arg, phi_block);
 286                                                 break;
 287                                         }
 288                                 }
 289                         }
 290
 291                         if (is_pinned(arg)) {
 292                                 /*
 293                                         Insert a duplicate of the original value in arguments block,
 294                                         make it the new phi arg,
 295                                         set its register,
 296                                         insert it into schedule,
 297                                         pin it
 298                                 */
 299                                 ir_node *perm = get_Proj_pred(arg);
 300                                 ir_node *dupl = be_new_Copy(arg_block, arg);
 301
 302                                 set_irn_n(phi, i, dupl);
 303                                 arch_set_irn_register(dupl, phi_reg);
 304                                 sched_add_after(perm, dupl);
 305                                 pin_irn(dupl, phi_block);
 306                                 be_liveness_introduce(lv, dupl);
 307                                 be_liveness_update(lv, arg);
 308                                 DBG((dbg, LEVEL_1, "      arg is pinned: insert %+F(%s)\n", dupl, arch_get_irn_register(dupl)->name));
 309                         } else {
 310                                 /*
 311                                         No other phi has the same color (else arg would have been pinned),
 312                                         so just set the register and pin
 313                                 */
 314                                 arch_set_irn_register(arg, phi_reg);
 315                                 pin_irn(arg, phi_block);
 316                                 DBG((dbg, LEVEL_1, "      arg is not pinned: so pin %+F(%s)\n", arg, arch_get_irn_register(arg)->name));
 317                         }
 318                 }
 319         }
 320 }
 321
 322 void be_ssa_destruction(be_chordal_env_t *chordal_env)
 323 {
 324         ir_graph *irg = chordal_env->irg;
 325
 326         FIRM_DBG_REGISTER(dbg, "ir.be.ssadestr");
 327
 328         be_invalidate_live_sets(irg);
 329
 330         /* create a map for fast lookup of perms: block --> perm */
 331         irg_walk_graph(irg, clear_link, collect_phis_walker, chordal_env);
 332
 333         DBG((dbg, LEVEL_1, "Placing perms...\n"));
 334         irg_block_walk_graph(irg, insert_all_perms_walker, NULL, chordal_env);
 335
 336         if (chordal_env->opts->dump_flags & BE_CH_DUMP_SSADESTR)
 337                 dump_ir_graph(irg, "ssa_destr_perms_placed");
 338
 339         be_assure_live_chk(irg);
 340
 341         DBG((dbg, LEVEL_1, "Setting regs and placing dupls...\n"));
 342         irg_block_walk_graph(irg, set_regs_or_place_dupls_walker, NULL, chordal_env);
 343
 344         /* unfortunately updating doesn't work yet. */
 345         be_invalidate_live_chk(irg);
 346
 347         if (chordal_env->opts->dump_flags & BE_CH_DUMP_SSADESTR)
 348                 dump_ir_graph(irg, "ssa_destr_regs_set");
 349 }
 350
 351 static void ssa_destruction_check_walker(ir_node *bl, void *data)
 352 {
 353         ir_node *phi;
 354         int i, max;
 355         (void)data;
 356
 357         for (phi = (ir_node*)get_irn_link(bl); phi != NULL;
 358              phi = (ir_node*)get_irn_link(phi)) {
 359                 const arch_register_t *phi_reg, *arg_reg;
 360
 361                 phi_reg = arch_get_irn_register(phi);
 362                 /* iterate over all args of phi */
 363                 for (i = 0, max = get_irn_arity(phi); i < max; ++i) {
 364                         ir_node                   *arg = get_irn_n(phi, i);
 365                         const arch_register_req_t *req = arch_get_irn_register_req(arg);
 366                         if (arch_register_req_is(req, ignore))
 367                                 continue;
 368
 369                         arg_reg = arch_get_irn_register(arg);
 370
 371                         if (phi_reg != arg_reg) {
 372                                 DBG((dbg, 0, "Error: Registers of %+F and %+F differ: %s %s\n", phi, arg, phi_reg->name, arg_reg->name));
 373                                 assert(0);
 374                         }
 375
 376                         if (! is_pinned(arg)) {
 377                                 DBG((dbg, 0, "Warning: Phi argument %+F is not pinned.\n", arg));
 378                                 assert(0);
 379                         }
 380                 }
 381         }
 382 }
 383
 384 void be_ssa_destruction_check(be_chordal_env_t *chordal_env)
 385 {
 386         irg_block_walk_graph(chordal_env->irg, ssa_destruction_check_walker, NULL, NULL);
 387 }