gcc/cfg.c

   1 /* Control flow graph manipulation code for GNU compiler.
   2    Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999, 2000, 2001, 2002 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to the Free
  19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  20 02111-1307, USA.  */
  21
  22 /* This file contains low level functions to manipulate the CFG and
  23    analyze it.  All other modules should not transform the datastructure
  24    directly and use abstraction instead.  The file is supposed to be
  25    ordered bottom-up and should not contain any code dependent on a
  26    particular intermediate language (RTL or trees).
  27
  28    Available functionality:
  29      - Initialization/deallocation
  30          init_flow, clear_edges
  31      - Low level basic block manipulation
  32          alloc_block, expunge_block
  33      - Edge manipulation
  34          make_edge, make_single_succ_edge, cached_make_edge, remove_edge
  35          - Low level edge redirection (without updating instruction chain)
  36              redirect_edge_succ, redirect_edge_succ_nodup, redirect_edge_pred
  37      - Dumping and debugging
  38          dump_flow_info, debug_flow_info, dump_edge_info
  39      - Allocation of AUX fields for basic blocks
  40          alloc_aux_for_blocks, free_aux_for_blocks, alloc_aux_for_block
  41      - clear_bb_flags
  42  */
  43 \f
  44 #include "config.h"
  45 #include "system.h"
  46 #include "tree.h"
  47 #include "rtl.h"
  48 #include "hard-reg-set.h"
  49 #include "basic-block.h"
  50 #include "regs.h"
  51 #include "flags.h"
  52 #include "output.h"
  53 #include "function.h"
  54 #include "except.h"
  55 #include "toplev.h"
  56 #include "tm_p.h"
  57 #include "obstack.h"
  58
  59 /* The obstack on which the flow graph components are allocated.  */
  60
  61 struct obstack flow_obstack;
  62 static char *flow_firstobj;
  63
  64 /* Number of basic blocks in the current function.  */
  65
  66 int n_basic_blocks;
  67
  68 /* First free basic block number.  */
  69
  70 int last_basic_block;
  71
  72 /* Number of edges in the current function.  */
  73
  74 int n_edges;
  75
  76 /* First edge in the deleted edges chain.  */
  77
  78 edge first_deleted_edge;
  79 static basic_block first_deleted_block;
  80
  81 /* The basic block array.  */
  82
  83 varray_type basic_block_info;
  84
  85 /* The special entry and exit blocks.  */
  86
  87 struct basic_block_def entry_exit_blocks[2]
  88 = {{NULL,                       /* head */
  89     NULL,                       /* end */
  90     NULL,                       /* head_tree */
  91     NULL,                       /* end_tree */
  92     NULL,                       /* pred */
  93     NULL,                       /* succ */
  94     NULL,                       /* local_set */
  95     NULL,                       /* cond_local_set */
  96     NULL,                       /* global_live_at_start */
  97     NULL,                       /* global_live_at_end */
  98     NULL,                       /* aux */
  99     ENTRY_BLOCK,                /* index */
 100     NULL,                       /* prev_bb */
 101     EXIT_BLOCK_PTR,             /* next_bb */
 102     0,                          /* loop_depth */
 103     NULL,                       /* loop_father */
 104     0,                          /* count */
 105     0,                          /* frequency */
 106     0                           /* flags */
 107   },
 108   {
 109     NULL,                       /* head */
 110     NULL,                       /* end */
 111     NULL,                       /* head_tree */
 112     NULL,                       /* end_tree */
 113     NULL,                       /* pred */
 114     NULL,                       /* succ */
 115     NULL,                       /* local_set */
 116     NULL,                       /* cond_local_set */
 117     NULL,                       /* global_live_at_start */
 118     NULL,                       /* global_live_at_end */
 119     NULL,                       /* aux */
 120     EXIT_BLOCK,                 /* index */
 121     ENTRY_BLOCK_PTR,            /* prev_bb */
 122     NULL,                       /* next_bb */
 123     0,                          /* loop_depth */
 124     NULL,                       /* loop_father */
 125     0,                          /* count */
 126     0,                          /* frequency */
 127     0                           /* flags */
 128   }
 129 };
 130
 131 void debug_flow_info                    PARAMS ((void));
 132 static void free_edge                   PARAMS ((edge));
 133 \f
 134 /* Called once at initialization time.  */
 135
 136 void
 137 init_flow ()
 138 {
 139   static int initialized;
 140
 141   first_deleted_edge = 0;
 142   first_deleted_block = 0;
 143   n_edges = 0;
 144
 145   if (!initialized)
 146     {
 147       gcc_obstack_init (&flow_obstack);
 148       flow_firstobj = (char *) obstack_alloc (&flow_obstack, 0);
 149       initialized = 1;
 150     }
 151   else
 152     {
 153       obstack_free (&flow_obstack, flow_firstobj);
 154       flow_firstobj = (char *) obstack_alloc (&flow_obstack, 0);
 155     }
 156 }
 157 \f
 158 /* Helper function for remove_edge and clear_edges.  Frees edge structure
 159    without actually unlinking it from the pred/succ lists.  */
 160
 161 static void
 162 free_edge (e)
 163      edge e;
 164 {
 165   n_edges--;
 166   memset (e, 0, sizeof *e);
 167   e->succ_next = first_deleted_edge;
 168   first_deleted_edge = e;
 169 }
 170
 171 /* Free the memory associated with the edge structures.  */
 172
 173 void
 174 clear_edges ()
 175 {
 176   basic_block bb;
 177   edge e;
 178
 179   FOR_EACH_BB (bb)
 180     {
 181       edge e = bb->succ;
 182
 183       while (e)
 184         {
 185           edge next = e->succ_next;
 186
 187           free_edge (e);
 188           e = next;
 189         }
 190
 191       bb->succ = NULL;
 192       bb->pred = NULL;
 193     }
 194
 195   e = ENTRY_BLOCK_PTR->succ;
 196   while (e)
 197     {
 198       edge next = e->succ_next;
 199
 200       free_edge (e);
 201       e = next;
 202     }
 203
 204   EXIT_BLOCK_PTR->pred = NULL;
 205   ENTRY_BLOCK_PTR->succ = NULL;
 206
 207   if (n_edges)
 208     abort ();
 209 }
 210 \f
 211 /* Allocate memory for basic_block.  */
 212
 213 basic_block
 214 alloc_block ()
 215 {
 216   basic_block bb;
 217
 218   if (first_deleted_block)
 219     {
 220       bb = first_deleted_block;
 221       first_deleted_block = (basic_block) bb->succ;
 222       bb->succ = NULL;
 223     }
 224   else
 225     {
 226       bb = (basic_block) obstack_alloc (&flow_obstack, sizeof *bb);
 227       memset (bb, 0, sizeof *bb);
 228     }
 229   return bb;
 230 }
 231
 232 /* Link block B to chain after AFTER.  */
 233 void
 234 link_block (b, after)
 235      basic_block b, after;
 236 {
 237   b->next_bb = after->next_bb;
 238   b->prev_bb = after;
 239   after->next_bb = b;
 240   b->next_bb->prev_bb = b;
 241 }
 242
 243 /* Unlink block B from chain.  */
 244 void
 245 unlink_block (b)
 246      basic_block b;
 247 {
 248   b->next_bb->prev_bb = b->prev_bb;
 249   b->prev_bb->next_bb = b->next_bb;
 250 }
 251
 252 /* Sequentially order blocks and compact the arrays.  */
 253 void
 254 compact_blocks ()
 255 {
 256   int i;
 257   basic_block bb;
 258
 259   i = 0;
 260   FOR_EACH_BB (bb)
 261     {
 262       BASIC_BLOCK (i) = bb;
 263       bb->index = i;
 264       i++;
 265     }
 266
 267   if (i != n_basic_blocks)
 268     abort ();
 269
 270   last_basic_block = n_basic_blocks;
 271 }
 272
 273
 274 /* Remove block B from the basic block array.  */
 275
 276 void
 277 expunge_block (b)
 278      basic_block b;
 279 {
 280   unlink_block (b);
 281   BASIC_BLOCK (b->index) = NULL;
 282   n_basic_blocks--;
 283
 284   /* Invalidate data to make bughunting easier.  */
 285   memset (b, 0, sizeof *b);
 286   b->index = -3;
 287   b->succ = (edge) first_deleted_block;
 288   first_deleted_block = (basic_block) b;
 289 }
 290 \f
 291 /* Create an edge connecting SRC and DST with FLAGS optionally using
 292    edge cache CACHE.  Return the new edge, NULL if already exist.  */
 293
 294 edge
 295 cached_make_edge (edge_cache, src, dst, flags)
 296      sbitmap *edge_cache;
 297      basic_block src, dst;
 298      int flags;
 299 {
 300   int use_edge_cache;
 301   edge e;
 302
 303   /* Don't bother with edge cache for ENTRY or EXIT, if there aren't that
 304      many edges to them, or we didn't allocate memory for it.  */
 305   use_edge_cache = (edge_cache
 306                     && src != ENTRY_BLOCK_PTR && dst != EXIT_BLOCK_PTR);
 307
 308   /* Make sure we don't add duplicate edges.  */
 309   switch (use_edge_cache)
 310     {
 311     default:
 312       /* Quick test for non-existence of the edge.  */
 313       if (! TEST_BIT (edge_cache[src->index], dst->index))
 314         break;
 315
 316       /* The edge exists; early exit if no work to do.  */
 317       if (flags == 0)
 318         return NULL;
 319
 320       /* FALLTHRU */
 321     case 0:
 322       for (e = src->succ; e; e = e->succ_next)
 323         if (e->dest == dst)
 324           {
 325             e->flags |= flags;
 326             return NULL;
 327           }
 328       break;
 329     }
 330
 331   if (first_deleted_edge)
 332     {
 333       e = first_deleted_edge;
 334       first_deleted_edge = e->succ_next;
 335     }
 336   else
 337     {
 338       e = (edge) obstack_alloc (&flow_obstack, sizeof *e);
 339       memset (e, 0, sizeof *e);
 340     }
 341   n_edges++;
 342
 343   e->succ_next = src->succ;
 344   e->pred_next = dst->pred;
 345   e->src = src;
 346   e->dest = dst;
 347   e->flags = flags;
 348
 349   src->succ = e;
 350   dst->pred = e;
 351
 352   if (use_edge_cache)
 353     SET_BIT (edge_cache[src->index], dst->index);
 354
 355   return e;
 356 }
 357
 358 /* Create an edge connecting SRC and DEST with flags FLAGS.  Return newly
 359    created edge or NULL if already exist.  */
 360
 361 edge
 362 make_edge (src, dest, flags)
 363      basic_block src, dest;
 364      int flags;
 365 {
 366   return cached_make_edge (NULL, src, dest, flags);
 367 }
 368
 369 /* Create an edge connecting SRC to DEST and set probability by knowing
 370    that it is the single edge leaving SRC.  */
 371
 372 edge
 373 make_single_succ_edge (src, dest, flags)
 374      basic_block src, dest;
 375      int flags;
 376 {
 377   edge e = make_edge (src, dest, flags);
 378
 379   e->probability = REG_BR_PROB_BASE;
 380   e->count = src->count;
 381   return e;
 382 }
 383
 384 /* This function will remove an edge from the flow graph.  */
 385
 386 void
 387 remove_edge (e)
 388      edge e;
 389 {
 390   edge last_pred = NULL;
 391   edge last_succ = NULL;
 392   edge tmp;
 393   basic_block src, dest;
 394
 395   src = e->src;
 396   dest = e->dest;
 397   for (tmp = src->succ; tmp && tmp != e; tmp = tmp->succ_next)
 398     last_succ = tmp;
 399
 400   if (!tmp)
 401     abort ();
 402   if (last_succ)
 403     last_succ->succ_next = e->succ_next;
 404   else
 405     src->succ = e->succ_next;
 406
 407   for (tmp = dest->pred; tmp && tmp != e; tmp = tmp->pred_next)
 408     last_pred = tmp;
 409
 410   if (!tmp)
 411     abort ();
 412   if (last_pred)
 413     last_pred->pred_next = e->pred_next;
 414   else
 415     dest->pred = e->pred_next;
 416
 417   free_edge (e);
 418 }
 419
 420 /* Redirect an edge's successor from one block to another.  */
 421
 422 void
 423 redirect_edge_succ (e, new_succ)
 424      edge e;
 425      basic_block new_succ;
 426 {
 427   edge *pe;
 428
 429   /* Disconnect the edge from the old successor block.  */
 430   for (pe = &e->dest->pred; *pe != e; pe = &(*pe)->pred_next)
 431     continue;
 432   *pe = (*pe)->pred_next;
 433
 434   /* Reconnect the edge to the new successor block.  */
 435   e->pred_next = new_succ->pred;
 436   new_succ->pred = e;
 437   e->dest = new_succ;
 438 }
 439
 440 /* Like previous but avoid possible duplicate edge.  */
 441
 442 edge
 443 redirect_edge_succ_nodup (e, new_succ)
 444      edge e;
 445      basic_block new_succ;
 446 {
 447   edge s;
 448
 449   /* Check whether the edge is already present.  */
 450   for (s = e->src->succ; s; s = s->succ_next)
 451     if (s->dest == new_succ && s != e)
 452       break;
 453
 454   if (s)
 455     {
 456       s->flags |= e->flags;
 457       s->probability += e->probability;
 458       if (s->probability > REG_BR_PROB_BASE)
 459         s->probability = REG_BR_PROB_BASE;
 460       s->count += e->count;
 461       remove_edge (e);
 462       e = s;
 463     }
 464   else
 465     redirect_edge_succ (e, new_succ);
 466
 467   return e;
 468 }
 469
 470 /* Redirect an edge's predecessor from one block to another.  */
 471
 472 void
 473 redirect_edge_pred (e, new_pred)
 474      edge e;
 475      basic_block new_pred;
 476 {
 477   edge *pe;
 478
 479   /* Disconnect the edge from the old predecessor block.  */
 480   for (pe = &e->src->succ; *pe != e; pe = &(*pe)->succ_next)
 481     continue;
 482
 483   *pe = (*pe)->succ_next;
 484
 485   /* Reconnect the edge to the new predecessor block.  */
 486   e->succ_next = new_pred->succ;
 487   new_pred->succ = e;
 488   e->src = new_pred;
 489 }
 490
 491 void
 492 clear_bb_flags ()
 493 {
 494   basic_block bb;
 495
 496   FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
 497     bb->flags = 0;
 498 }
 499 \f
 500 void
 501 dump_flow_info (file)
 502      FILE *file;
 503 {
 504   int i;
 505   basic_block bb;
 506   static const char * const reg_class_names[] = REG_CLASS_NAMES;
 507
 508   fprintf (file, "%d registers.\n", max_regno);
 509   for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
 510     if (REG_N_REFS (i))
 511       {
 512         enum reg_class class, altclass;
 513
 514         fprintf (file, "\nRegister %d used %d times across %d insns",
 515                  i, REG_N_REFS (i), REG_LIVE_LENGTH (i));
 516         if (REG_BASIC_BLOCK (i) >= 0)
 517           fprintf (file, " in block %d", REG_BASIC_BLOCK (i));
 518         if (REG_N_SETS (i))
 519           fprintf (file, "; set %d time%s", REG_N_SETS (i),
 520                    (REG_N_SETS (i) == 1) ? "" : "s");
 521         if (regno_reg_rtx[i] != NULL && REG_USERVAR_P (regno_reg_rtx[i]))
 522           fprintf (file, "; user var");
 523         if (REG_N_DEATHS (i) != 1)
 524           fprintf (file, "; dies in %d places", REG_N_DEATHS (i));
 525         if (REG_N_CALLS_CROSSED (i) == 1)
 526           fprintf (file, "; crosses 1 call");
 527         else if (REG_N_CALLS_CROSSED (i))
 528           fprintf (file, "; crosses %d calls", REG_N_CALLS_CROSSED (i));
 529         if (regno_reg_rtx[i] != NULL
 530             && PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD)
 531           fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i));
 532
 533         class = reg_preferred_class (i);
 534         altclass = reg_alternate_class (i);
 535         if (class != GENERAL_REGS || altclass != ALL_REGS)
 536           {
 537             if (altclass == ALL_REGS || class == ALL_REGS)
 538               fprintf (file, "; pref %s", reg_class_names[(int) class]);
 539             else if (altclass == NO_REGS)
 540               fprintf (file, "; %s or none", reg_class_names[(int) class]);
 541             else
 542               fprintf (file, "; pref %s, else %s",
 543                        reg_class_names[(int) class],
 544                        reg_class_names[(int) altclass]);
 545           }
 546
 547         if (regno_reg_rtx[i] != NULL && REG_POINTER (regno_reg_rtx[i]))
 548           fprintf (file, "; pointer");
 549         fprintf (file, ".\n");
 550       }
 551
 552   fprintf (file, "\n%d basic blocks, %d edges.\n", n_basic_blocks, n_edges);
 553   FOR_EACH_BB (bb)
 554     {
 555       edge e;
 556       int sum;
 557       gcov_type lsum;
 558
 559       fprintf (file, "\nBasic block %d: first insn %d, last %d, ",
 560                bb->index, INSN_UID (bb->head), INSN_UID (bb->end));
 561       fprintf (file, "prev %d, next %d, ",
 562                bb->prev_bb->index, bb->next_bb->index);
 563       fprintf (file, "loop_depth %d, count ", bb->loop_depth);
 564       fprintf (file, HOST_WIDEST_INT_PRINT_DEC, bb->count);
 565       fprintf (file, ", freq %i", bb->frequency);
 566       if (maybe_hot_bb_p (bb))
 567         fprintf (file, ", maybe hot");
 568       if (probably_never_executed_bb_p (bb))
 569         fprintf (file, ", probably never executed");
 570       fprintf (file, ".\n");
 571
 572       fprintf (file, "Predecessors: ");
 573       for (e = bb->pred; e; e = e->pred_next)
 574         dump_edge_info (file, e, 0);
 575
 576       fprintf (file, "\nSuccessors: ");
 577       for (e = bb->succ; e; e = e->succ_next)
 578         dump_edge_info (file, e, 1);
 579
 580       fprintf (file, "\nRegisters live at start:");
 581       dump_regset (bb->global_live_at_start, file);
 582
 583       fprintf (file, "\nRegisters live at end:");
 584       dump_regset (bb->global_live_at_end, file);
 585
 586       putc ('\n', file);
 587
 588       /* Check the consistency of profile information.  We can't do that
 589          in verify_flow_info, as the counts may get invalid for incompletely
 590          solved graphs, later elliminating of conditionals or roundoff errors.
 591          It is still practical to have them reported for debugging of simple
 592          testcases.  */
 593       sum = 0;
 594       for (e = bb->succ; e; e = e->succ_next)
 595         sum += e->probability;
 596       if (bb->succ && abs (sum - REG_BR_PROB_BASE) > 100)
 597         fprintf (file, "Invalid sum of outgoing probabilities %.1f%%\n",
 598                  sum * 100.0 / REG_BR_PROB_BASE);
 599       sum = 0;
 600       for (e = bb->pred; e; e = e->pred_next)
 601         sum += EDGE_FREQUENCY (e);
 602       if (abs (sum - bb->frequency) > 100)
 603         fprintf (file,
 604                  "Invalid sum of incomming frequencies %i, should be %i\n",
 605                  sum, bb->frequency);
 606       lsum = 0;
 607       for (e = bb->pred; e; e = e->pred_next)
 608         lsum += e->count;
 609       if (lsum - bb->count > 100 || lsum - bb->count < -100)
 610         fprintf (file, "Invalid sum of incomming counts %i, should be %i\n",
 611                  (int)lsum, (int)bb->count);
 612       lsum = 0;
 613       for (e = bb->succ; e; e = e->succ_next)
 614         lsum += e->count;
 615       if (bb->succ && (lsum - bb->count > 100 || lsum - bb->count < -100))
 616         fprintf (file, "Invalid sum of incomming counts %i, should be %i\n",
 617                  (int)lsum, (int)bb->count);
 618     }
 619
 620   putc ('\n', file);
 621 }
 622
 623 void
 624 debug_flow_info ()
 625 {
 626   dump_flow_info (stderr);
 627 }
 628
 629 void
 630 dump_edge_info (file, e, do_succ)
 631      FILE *file;
 632      edge e;
 633      int do_succ;
 634 {
 635   basic_block side = (do_succ ? e->dest : e->src);
 636
 637   if (side == ENTRY_BLOCK_PTR)
 638     fputs (" ENTRY", file);
 639   else if (side == EXIT_BLOCK_PTR)
 640     fputs (" EXIT", file);
 641   else
 642     fprintf (file, " %d", side->index);
 643
 644   if (e->probability)
 645     fprintf (file, " [%.1f%%] ", e->probability * 100.0 / REG_BR_PROB_BASE);
 646
 647   if (e->count)
 648     {
 649       fprintf (file, " count:");
 650       fprintf (file, HOST_WIDEST_INT_PRINT_DEC, e->count);
 651     }
 652
 653   if (e->flags)
 654     {
 655       static const char * const bitnames[]
 656         = {"fallthru", "ab", "abcall", "eh", "fake", "dfs_back", "can_fallthru"};
 657       int comma = 0;
 658       int i, flags = e->flags;
 659
 660       fputs (" (", file);
 661       for (i = 0; flags; i++)
 662         if (flags & (1 << i))
 663           {
 664             flags &= ~(1 << i);
 665
 666             if (comma)
 667               fputc (',', file);
 668             if (i < (int) ARRAY_SIZE (bitnames))
 669               fputs (bitnames[i], file);
 670             else
 671               fprintf (file, "%d", i);
 672             comma = 1;
 673           }
 674
 675       fputc (')', file);
 676     }
 677 }
 678 \f
 679 /* Simple routines to easily allocate AUX fields of basic blocks.  */
 680
 681 static struct obstack block_aux_obstack;
 682 static void *first_block_aux_obj = 0;
 683 static struct obstack edge_aux_obstack;
 684 static void *first_edge_aux_obj = 0;
 685
 686 /* Allocate an memory block of SIZE as BB->aux.  The obstack must
 687    be first initialized by alloc_aux_for_blocks.  */
 688
 689 inline void
 690 alloc_aux_for_block (bb, size)
 691      basic_block bb;
 692      int size;
 693 {
 694   /* Verify that aux field is clear.  */
 695   if (bb->aux || !first_block_aux_obj)
 696     abort ();
 697   bb->aux = obstack_alloc (&block_aux_obstack, size);
 698   memset (bb->aux, 0, size);
 699 }
 700
 701 /* Initialize the block_aux_obstack and if SIZE is nonzero, call
 702    alloc_aux_for_block for each basic block.  */
 703
 704 void
 705 alloc_aux_for_blocks (size)
 706      int size;
 707 {
 708   static int initialized;
 709
 710   if (!initialized)
 711     {
 712       gcc_obstack_init (&block_aux_obstack);
 713       initialized = 1;
 714     }
 715
 716   /* Check whether AUX data are still allocated.  */
 717   else if (first_block_aux_obj)
 718     abort ();
 719   first_block_aux_obj = (char *) obstack_alloc (&block_aux_obstack, 0);
 720   if (size)
 721     {
 722       basic_block bb;
 723
 724       FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
 725         alloc_aux_for_block (bb, size);
 726     }
 727 }
 728
 729 /* Clear AUX pointers of all blocks.  */
 730
 731 void
 732 clear_aux_for_blocks ()
 733 {
 734   basic_block bb;
 735
 736   FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
 737     bb->aux = NULL;
 738 }
 739
 740 /* Free data allocated in block_aux_obstack and clear AUX pointers
 741    of all blocks.  */
 742
 743 void
 744 free_aux_for_blocks ()
 745 {
 746   if (!first_block_aux_obj)
 747     abort ();
 748   obstack_free (&block_aux_obstack, first_block_aux_obj);
 749   first_block_aux_obj = NULL;
 750
 751   clear_aux_for_blocks ();
 752 }
 753
 754 /* Allocate an memory edge of SIZE as BB->aux.  The obstack must
 755    be first initialized by alloc_aux_for_edges.  */
 756
 757 inline void
 758 alloc_aux_for_edge (e, size)
 759      edge e;
 760      int size;
 761 {
 762   /* Verify that aux field is clear.  */
 763   if (e->aux || !first_edge_aux_obj)
 764     abort ();
 765   e->aux = obstack_alloc (&edge_aux_obstack, size);
 766   memset (e->aux, 0, size);
 767 }
 768
 769 /* Initialize the edge_aux_obstack and if SIZE is nonzero, call
 770    alloc_aux_for_edge for each basic edge.  */
 771
 772 void
 773 alloc_aux_for_edges (size)
 774      int size;
 775 {
 776   static int initialized;
 777
 778   if (!initialized)
 779     {
 780       gcc_obstack_init (&edge_aux_obstack);
 781       initialized = 1;
 782     }
 783
 784   /* Check whether AUX data are still allocated.  */
 785   else if (first_edge_aux_obj)
 786     abort ();
 787
 788   first_edge_aux_obj = (char *) obstack_alloc (&edge_aux_obstack, 0);
 789   if (size)
 790     {
 791       basic_block bb;
 792
 793       FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
 794         {
 795           edge e;
 796
 797           for (e = bb->succ; e; e = e->succ_next)
 798             alloc_aux_for_edge (e, size);
 799         }
 800     }
 801 }
 802
 803 /* Clear AUX pointers of all edges.  */
 804
 805 void
 806 clear_aux_for_edges ()
 807 {
 808   basic_block bb;
 809   edge e;
 810
 811   FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
 812     {
 813       for (e = bb->succ; e; e = e->succ_next)
 814         e->aux = NULL;
 815     }
 816 }
 817
 818 /* Free data allocated in edge_aux_obstack and clear AUX pointers
 819    of all edges.  */
 820
 821 void
 822 free_aux_for_edges ()
 823 {
 824   if (!first_edge_aux_obj)
 825     abort ();
 826   obstack_free (&edge_aux_obstack, first_edge_aux_obj);
 827   first_edge_aux_obj = NULL;
 828
 829   clear_aux_for_edges ();
 830 }