gcc/gensupport.c

   1 /* Support routines for the various generation passes.
   2    Copyright (C) 2000 Free Software Foundation, Inc.
   3
   4    This file is part of GNU CC.
   5
   6    GNU CC is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2, or (at your option)
   9    any later version.
  10
  11    GNU CC is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with GNU CC; see the file COPYING.  If not, write to
  18    the Free Software Foundation, 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include "hconfig.h"
  22 #include "system.h"
  23 #include "rtl.h"
  24 #include "obstack.h"
  25 #include "errors.h"
  26 #include "gensupport.h"
  27
  28
  29 static struct obstack obstack;
  30 struct obstack *rtl_obstack = &obstack;
  31
  32 #define obstack_chunk_alloc xmalloc
  33 #define obstack_chunk_free free
  34
  35 static int sequence_num;
  36 static int errors;
  37
  38 static int predicable_default;
  39 static const char *predicable_true;
  40 static const char *predicable_false;
  41
  42 /* We initially queue all patterns, process the define_insn and
  43    define_cond_exec patterns, then return them one at a time.  */
  44
  45 struct queue_elem
  46 {
  47   rtx data;
  48   int lineno;
  49   struct queue_elem *next;
  50 };
  51
  52 static struct queue_elem *define_attr_queue;
  53 static struct queue_elem **define_attr_tail = &define_attr_queue;
  54 static struct queue_elem *define_insn_queue;
  55 static struct queue_elem **define_insn_tail = &define_insn_queue;
  56 static struct queue_elem *define_cond_exec_queue;
  57 static struct queue_elem **define_cond_exec_tail = &define_cond_exec_queue;
  58 static struct queue_elem *other_queue;
  59 static struct queue_elem **other_tail = &other_queue;
  60
  61 static void queue_pattern PARAMS ((rtx, struct queue_elem ***, int));
  62 static void remove_constraints PARAMS ((rtx));
  63 static void process_rtx PARAMS ((rtx, int));
  64
  65 static int is_predicable PARAMS ((struct queue_elem *));
  66 static void identify_predicable_attribute PARAMS ((void));
  67 static int n_alternatives PARAMS ((const char *));
  68 static void collect_insn_data PARAMS ((rtx, int *, int *));
  69 static rtx alter_predicate_for_insn PARAMS ((rtx, int, int, int));
  70 static const char *alter_test_for_insn PARAMS ((struct queue_elem *,
  71                                                 struct queue_elem *));
  72 static char *shift_output_template PARAMS ((char *, const char *, int));
  73 static const char *alter_output_for_insn PARAMS ((struct queue_elem *,
  74                                                   struct queue_elem *,
  75                                                   int, int));
  76 static void process_one_cond_exec PARAMS ((struct queue_elem *));
  77 static void process_define_cond_exec PARAMS ((void));
  78 \f
  79 void
  80 message_with_line VPARAMS ((int lineno, const char *msg, ...))
  81 {
  82 #ifndef ANSI_PROTOTYPES
  83   int lineno;
  84   const char *msg;
  85 #endif
  86   va_list ap;
  87
  88   VA_START (ap, msg);
  89
  90 #ifndef ANSI_PROTOTYPES
  91   lineno = va_arg (ap, int);
  92   msg = va_arg (ap, const char *);
  93 #endif
  94
  95   fprintf (stderr, "%s:%d: ", read_rtx_filename, lineno);
  96   vfprintf (stderr, msg, ap);
  97   fputc ('\n', stderr);
  98
  99   va_end (ap);
 100 }
 101 \f
 102 /* Queue PATTERN on LIST_TAIL.  */
 103
 104 static void
 105 queue_pattern (pattern, list_tail, lineno)
 106      rtx pattern;
 107      struct queue_elem ***list_tail;
 108      int lineno;
 109 {
 110   struct queue_elem *e = (struct queue_elem *) xmalloc (sizeof (*e));
 111   e->data = pattern;
 112   e->lineno = lineno;
 113   e->next = NULL;
 114   **list_tail = e;
 115   *list_tail = &e->next;
 116 }
 117
 118 /* Recursively remove constraints from an rtx.  */
 119
 120 static void
 121 remove_constraints (part)
 122      rtx part;
 123 {
 124   register int i, j;
 125   register const char *format_ptr;
 126
 127   if (part == 0)
 128     return;
 129
 130   if (GET_CODE (part) == MATCH_OPERAND)
 131     XSTR (part, 2) = "";
 132   else if (GET_CODE (part) == MATCH_SCRATCH)
 133     XSTR (part, 1) = "";
 134
 135   format_ptr = GET_RTX_FORMAT (GET_CODE (part));
 136
 137   for (i = 0; i < GET_RTX_LENGTH (GET_CODE (part)); i++)
 138     switch (*format_ptr++)
 139       {
 140       case 'e':
 141       case 'u':
 142         remove_constraints (XEXP (part, i));
 143         break;
 144       case 'E':
 145         if (XVEC (part, i) != NULL)
 146           for (j = 0; j < XVECLEN (part, i); j++)
 147             remove_constraints (XVECEXP (part, i, j));
 148         break;
 149       }
 150 }
 151
 152 /* Process a top level rtx in some way, queueing as appropriate.  */
 153
 154 static void
 155 process_rtx (desc, lineno)
 156      rtx desc;
 157      int lineno;
 158 {
 159   switch (GET_CODE (desc))
 160     {
 161     case DEFINE_INSN:
 162       queue_pattern (desc, &define_insn_tail, lineno);
 163       break;
 164
 165     case DEFINE_COND_EXEC:
 166       queue_pattern (desc, &define_cond_exec_tail, lineno);
 167       break;
 168
 169     case DEFINE_ATTR:
 170       queue_pattern (desc, &define_attr_tail, lineno);
 171       break;
 172
 173     case DEFINE_INSN_AND_SPLIT:
 174       {
 175         const char *split_cond;
 176         rtx split;
 177         rtvec attr;
 178         int i;
 179
 180         /* Create a split with values from the insn_and_split. */
 181         split = rtx_alloc (DEFINE_SPLIT);
 182
 183         i = XVECLEN (desc, 1);
 184         XVEC (split, 0) = rtvec_alloc (i);
 185         while (--i >= 0)
 186           {
 187             XVECEXP (split, 0, i) = copy_rtx (XVECEXP (desc, 1, i));
 188             remove_constraints (XVECEXP (split, 0, i));
 189           }
 190
 191         /* If the split condition starts with "&&", append it to the
 192            insn condition to create the new split condition.  */
 193         split_cond = XSTR (desc, 4);
 194         if (split_cond[0] == '&' && split_cond[1] == '&')
 195           {
 196             const char *insn_cond = XSTR (desc, 2);
 197             size_t insn_cond_len = strlen (insn_cond);
 198             size_t split_cond_len = strlen (split_cond);
 199             char *combined;
 200
 201             combined = (char *) xmalloc (insn_cond_len + split_cond_len + 1);
 202             memcpy (combined, insn_cond, insn_cond_len);
 203             memcpy (combined + insn_cond_len, split_cond, split_cond_len + 1);
 204
 205             split_cond = combined;
 206           }
 207         XSTR (split, 1) = split_cond;
 208         XVEC (split, 2) = XVEC (desc, 5);
 209         XSTR (split, 3) = XSTR (desc, 6);
 210
 211         /* Fix up the DEFINE_INSN.  */
 212         attr = XVEC (desc, 7);
 213         PUT_CODE (desc, DEFINE_INSN);
 214         XVEC (desc, 4) = attr;
 215
 216         /* Queue them.  */
 217         queue_pattern (desc, &define_insn_tail, lineno);
 218         queue_pattern (split, &other_tail, lineno);
 219         break;
 220       }
 221
 222     default:
 223       queue_pattern (desc, &other_tail, lineno);
 224       break;
 225     }
 226 }
 227 \f
 228 /* Return true if attribute PREDICABLE is true for ELEM, which holds
 229    a DEFINE_INSN.  */
 230
 231 static int
 232 is_predicable (elem)
 233      struct queue_elem *elem;
 234 {
 235   rtvec vec = XVEC (elem->data, 4);
 236   const char *value;
 237   int i;
 238
 239   if (! vec)
 240     return predicable_default;
 241
 242   for (i = GET_NUM_ELEM (vec) - 1; i >= 0; --i)
 243     {
 244       rtx sub = RTVEC_ELT (vec, i);
 245       switch (GET_CODE (sub))
 246         {
 247         case SET_ATTR:
 248           if (strcmp (XSTR (sub, 0), "predicable") == 0)
 249             {
 250               value = XSTR (sub, 1);
 251               goto found;
 252             }
 253           break;
 254
 255         case SET_ATTR_ALTERNATIVE:
 256           if (strcmp (XSTR (sub, 0), "predicable") == 0)
 257             {
 258               message_with_line (elem->lineno,
 259                                  "multiple alternatives for `predicable'");
 260               errors = 1;
 261               return 0;
 262             }
 263           break;
 264
 265         case SET:
 266           if (GET_CODE (SET_DEST (sub)) != ATTR
 267               || strcmp (XSTR (SET_DEST (sub), 0), "predicable") != 0)
 268             break;
 269           sub = SET_SRC (sub);
 270           if (GET_CODE (sub) == CONST_STRING)
 271             {
 272               value = XSTR (sub, 0);
 273               goto found;
 274             }
 275
 276           /* ??? It would be possible to handle this if we really tried.
 277              It's not easy though, and I'm not going to bother until it
 278              really proves necessary.  */
 279           message_with_line (elem->lineno,
 280                              "non-constant value for `predicable'");
 281           errors = 1;
 282           return 0;
 283
 284         default:
 285           abort ();
 286         }
 287     }
 288
 289   return predicable_default;
 290
 291  found:
 292   /* Verify that predicability does not vary on the alternative.  */
 293   /* ??? It should be possible to handle this by simply eliminating
 294      the non-predicable alternatives from the insn.  FRV would like
 295      to do this.  Delay this until we've got the basics solid.  */
 296   if (strchr (value, ',') != NULL)
 297     {
 298       message_with_line (elem->lineno,
 299                          "multiple alternatives for `predicable'");
 300       errors = 1;
 301       return 0;
 302     }
 303
 304   /* Find out which value we're looking at.  */
 305   if (strcmp (value, predicable_true) == 0)
 306     return 1;
 307   if (strcmp (value, predicable_false) == 0)
 308     return 0;
 309
 310   message_with_line (elem->lineno,
 311                      "Unknown value `%s' for `predicable' attribute",
 312                      value);
 313   errors = 1;
 314   return 0;
 315 }
 316
 317 /* Examine the attribute "predicable"; discover its boolean values
 318    and its default.  */
 319
 320 static void
 321 identify_predicable_attribute ()
 322 {
 323   struct queue_elem *elem;
 324   char *true, *false;
 325   const char *value;
 326   size_t len;
 327
 328   /* Look for the DEFINE_ATTR for `predicable', which must exist.  */
 329   for (elem = define_attr_queue; elem ; elem = elem->next)
 330     if (strcmp (XSTR (elem->data, 0), "predicable") == 0)
 331       goto found;
 332
 333   message_with_line (define_cond_exec_queue->lineno,
 334                      "Attribute `predicable' not defined");
 335   errors = 1;
 336   return;
 337
 338  found:
 339   value = XSTR (elem->data, 1);
 340   len = strlen (value);
 341   false = (char *) xmalloc (len + 1);
 342   memcpy (false, value, len + 1);
 343
 344   true = strchr (false, ',');
 345   if (true == NULL || strchr (++true, ',') != NULL)
 346     {
 347       message_with_line (elem->lineno,
 348                          "Attribute `predicable' is not a boolean");
 349       errors = 1;
 350       return;
 351     }
 352   true[-1] = '\0';
 353
 354   predicable_true = true;
 355   predicable_false = false;
 356
 357   switch (GET_CODE (XEXP (elem->data, 2)))
 358     {
 359     case CONST_STRING:
 360       value = XSTR (XEXP (elem->data, 2), 0);
 361       break;
 362
 363     case CONST:
 364       message_with_line (elem->lineno,
 365                          "Attribute `predicable' cannot be const");
 366       errors = 1;
 367       return;
 368
 369     default:
 370       message_with_line (elem->lineno,
 371                          "Attribute `predicable' must have a constant default");
 372       errors = 1;
 373       return;
 374     }
 375
 376   if (strcmp (value, true) == 0)
 377     predicable_default = 1;
 378   else if (strcmp (value, false) == 0)
 379     predicable_default = 0;
 380   else
 381     {
 382       message_with_line (elem->lineno,
 383                          "Unknown value `%s' for `predicable' attribute",
 384                          value);
 385       errors = 1;
 386     }
 387 }
 388
 389 /* Return the number of alternatives in constraint S.  */
 390
 391 static int
 392 n_alternatives (s)
 393      const char *s;
 394 {
 395   int n = 1;
 396
 397   if (s)
 398     while (*s)
 399       n += (*s++ == ',');
 400
 401   return n;
 402 }
 403
 404 /* Determine how many alternatives there are in INSN, and how many
 405    operands.  */
 406
 407 static void
 408 collect_insn_data (pattern, palt, pmax)
 409      rtx pattern;
 410      int *palt, *pmax;
 411 {
 412   const char *fmt;
 413   enum rtx_code code;
 414   int i, j, len;
 415
 416   code = GET_CODE (pattern);
 417   switch (code)
 418     {
 419     case MATCH_OPERAND:
 420       i = n_alternatives (XSTR (pattern, 2));
 421       *palt = (i > *palt ? i : *palt);
 422       /* FALLTHRU */
 423
 424     case MATCH_OPERATOR:
 425     case MATCH_SCRATCH:
 426     case MATCH_PARALLEL:
 427     case MATCH_INSN:
 428       i = XINT (pattern, 0);
 429       if (i > *pmax)
 430         *pmax = i;
 431       break;
 432
 433     default:
 434       break;
 435     }
 436
 437   fmt = GET_RTX_FORMAT (code);
 438   len = GET_RTX_LENGTH (code);
 439   for (i = 0; i < len; i++)
 440     {
 441       switch (fmt[i])
 442         {
 443         case 'e': case 'u':
 444           collect_insn_data (XEXP (pattern, i), palt, pmax);
 445           break;
 446
 447         case 'V':
 448           if (XVEC (pattern, i) == NULL)
 449             break;
 450           /* FALLTHRU */
 451         case 'E':
 452           for (j = XVECLEN (pattern, i) - 1; j >= 0; --j)
 453             collect_insn_data (XVECEXP (pattern, i, j), palt, pmax);
 454           break;
 455
 456         case 'i': case 'w': case '0': case 's': case 'S':
 457           break;
 458
 459         default:
 460           abort ();
 461         }
 462     }
 463 }
 464
 465 static rtx
 466 alter_predicate_for_insn (pattern, alt, max_op, lineno)
 467      rtx pattern;
 468      int alt, max_op, lineno;
 469 {
 470   const char *fmt;
 471   enum rtx_code code;
 472   int i, j, len;
 473
 474   code = GET_CODE (pattern);
 475   switch (code)
 476     {
 477     case MATCH_OPERAND:
 478       {
 479         const char *c = XSTR (pattern, 2);
 480
 481         if (n_alternatives (c) != 1)
 482           {
 483             message_with_line (lineno,
 484                                "Too many alternatives for operand %d",
 485                                XINT (pattern, 0));
 486             errors = 1;
 487             return NULL;
 488           }
 489
 490         /* Replicate C as needed to fill out ALT alternatives.  */
 491         if (c && *c && alt > 1)
 492           {
 493             size_t c_len = strlen (c);
 494             size_t len = alt * (c_len + 1);
 495             char *new_c = (char *) xmalloc (len);
 496
 497             memcpy (new_c, c, c_len);
 498             for (i = 1; i < alt; ++i)
 499               {
 500                 new_c[i * (c_len + 1) - 1] = ',';
 501                 memcpy (&new_c[i * (c_len + 1)], c, c_len);
 502               }
 503             new_c[len - 1] = '\0';
 504             XSTR (pattern, 2) = new_c;
 505           }
 506       }
 507       /* FALLTHRU */
 508
 509     case MATCH_OPERATOR:
 510     case MATCH_SCRATCH:
 511     case MATCH_PARALLEL:
 512     case MATCH_INSN:
 513       XINT (pattern, 0) += max_op;
 514       break;
 515
 516     default:
 517       break;
 518     }
 519
 520   fmt = GET_RTX_FORMAT (code);
 521   len = GET_RTX_LENGTH (code);
 522   for (i = 0; i < len; i++)
 523     {
 524       rtx r;
 525
 526       switch (fmt[i])
 527         {
 528         case 'e': case 'u':
 529           r = alter_predicate_for_insn (XEXP (pattern, i), alt,
 530                                         max_op, lineno);
 531           if (r == NULL)
 532             return r;
 533           break;
 534
 535         case 'E':
 536           for (j = XVECLEN (pattern, i) - 1; j >= 0; --j)
 537             {
 538               r = alter_predicate_for_insn (XVECEXP (pattern, i, j),
 539                                             alt, max_op, lineno);
 540               if (r == NULL)
 541                 return r;
 542             }
 543           break;
 544
 545         case 'i': case 'w': case '0': case 's':
 546           break;
 547
 548         default:
 549           abort ();
 550         }
 551     }
 552
 553   return pattern;
 554 }
 555
 556 static const char *
 557 alter_test_for_insn (ce_elem, insn_elem)
 558      struct queue_elem *ce_elem, *insn_elem;
 559 {
 560   const char *ce_test, *insn_test;
 561   char *new_test;
 562   size_t len, ce_len, insn_len;
 563
 564   ce_test = XSTR (ce_elem->data, 1);
 565   insn_test = XSTR (insn_elem->data, 2);
 566   if (!ce_test || *ce_test == '\0')
 567     return insn_test;
 568   if (!insn_test || *insn_test == '\0')
 569     return ce_test;
 570
 571   ce_len = strlen (ce_test);
 572   insn_len = strlen (insn_test);
 573   len = 1 + ce_len + 1 + 4 + 1 + insn_len + 1 + 1;
 574   new_test = (char *) xmalloc (len);
 575
 576   sprintf (new_test, "(%s) && (%s)", ce_test, insn_test);
 577
 578   return new_test;
 579 }
 580
 581 /* Adjust all of the operand numbers in OLD to match the shift they'll
 582    get from an operand displacement of DISP.  Return a pointer after the
 583    adjusted string.  */
 584
 585 static char *
 586 shift_output_template (new, old, disp)
 587      char *new;
 588      const char *old;
 589      int disp;
 590 {
 591   while (*old)
 592     {
 593       char c = *old++;
 594       *new++ = c;
 595       if (c == '%')
 596         {
 597           c = *old++;
 598           if (ISDIGIT ((unsigned char) c))
 599             c += disp;
 600           else if (ISUPPER ((unsigned char) c)
 601                    || ISLOWER ((unsigned char) c))
 602             {
 603               *new++ = c;
 604               c = *old++ + disp;
 605             }
 606           *new++ = c;
 607         }
 608     }
 609
 610   return new;
 611 }
 612
 613 static const char *
 614 alter_output_for_insn (ce_elem, insn_elem, alt, max_op)
 615      struct queue_elem *ce_elem, *insn_elem;
 616      int alt, max_op;
 617 {
 618   const char *ce_out, *insn_out;
 619   char *new, *p;
 620   size_t len, ce_len, insn_len;
 621
 622   /* ??? Could coordinate with genoutput to not duplicate code here.  */
 623
 624   ce_out = XSTR (ce_elem->data, 2);
 625   insn_out = XSTR (insn_elem->data, 3);
 626   if (!ce_out || *ce_out == '\0')
 627     return insn_out;
 628
 629   ce_len = strlen (ce_out);
 630   insn_len = strlen (insn_out);
 631
 632   if (*insn_out == '*')
 633     /* You must take care of the predicate yourself.  */
 634     return insn_out;
 635
 636   if (*insn_out == '@')
 637     {
 638       len = (ce_len + 1) * alt + insn_len + 1;
 639       p = new = xmalloc (len);
 640
 641       do
 642         {
 643           do
 644             *p++ = *insn_out++;
 645           while (ISSPACE ((unsigned char) *insn_out));
 646
 647           if (*insn_out != '#')
 648             {
 649               p = shift_output_template (p, ce_out, max_op);
 650               *p++ = ' ';
 651             }
 652
 653           do
 654             *p++ = *insn_out++;
 655           while (*insn_out && *insn_out != '\n');
 656         }
 657       while (*insn_out);
 658       *p = '\0';
 659     }
 660   else
 661     {
 662       len = ce_len + 1 + insn_len + 1;
 663       new = xmalloc (len);
 664
 665       p = shift_output_template (new, ce_out, max_op);
 666       *p++ = ' ';
 667       memcpy (p, insn_out, insn_len + 1);
 668     }
 669
 670   return new;
 671 }
 672
 673 /* Replicate insns as appropriate for the given DEFINE_COND_EXEC.  */
 674
 675 static void
 676 process_one_cond_exec (ce_elem)
 677      struct queue_elem *ce_elem;
 678 {
 679   struct queue_elem *insn_elem;
 680   for (insn_elem = define_insn_queue; insn_elem ; insn_elem = insn_elem->next)
 681     {
 682       int alternatives, max_operand;
 683       rtx pred, insn, pattern;
 684
 685       if (! is_predicable (insn_elem))
 686         continue;
 687
 688       alternatives = 1;
 689       max_operand = -1;
 690       collect_insn_data (insn_elem->data, &alternatives, &max_operand);
 691       max_operand += 1;
 692
 693       if (XVECLEN (ce_elem->data, 0) != 1)
 694         {
 695           message_with_line (ce_elem->lineno,
 696                              "too many patterns in predicate");
 697           errors = 1;
 698           return;
 699         }
 700
 701       pred = copy_rtx (XVECEXP (ce_elem->data, 0, 0));
 702       pred = alter_predicate_for_insn (pred, alternatives, max_operand,
 703                                        ce_elem->lineno);
 704       if (pred == NULL)
 705         return;
 706
 707       /* Construct a new pattern for the new insn.  */
 708       insn = copy_rtx (insn_elem->data);
 709       XSTR (insn, 0) = "";
 710       pattern = rtx_alloc (COND_EXEC);
 711       XEXP (pattern, 0) = pred;
 712       if (XVECLEN (insn, 1) == 1)
 713         {
 714           XEXP (pattern, 1) = XVECEXP (insn, 1, 0);
 715           XVECEXP (insn, 1, 0) = pattern;
 716           PUT_NUM_ELEM (XVEC (insn, 1), 1);
 717         }
 718       else
 719         {
 720           XEXP (pattern, 1) = rtx_alloc (PARALLEL);
 721           XVEC (XEXP (pattern, 1), 0) = XVEC (insn, 1);
 722           XVEC (insn, 1) = rtvec_alloc (1);
 723           XVECEXP (insn, 1, 0) = pattern;
 724         }
 725
 726       XSTR (insn, 2) = alter_test_for_insn (ce_elem, insn_elem);
 727       XSTR (insn, 3) = alter_output_for_insn (ce_elem, insn_elem,
 728                                               alternatives, max_operand);
 729
 730       /* ??? Set `predicable' to false.  Not crucial since it's really
 731          only used here, and we won't reprocess this new pattern.  */
 732
 733       /* Put the new pattern on the `other' list so that it
 734          (a) is not reprocessed by other define_cond_exec patterns
 735          (b) appears after all normal define_insn patterns.
 736
 737          ??? B is debatable.  If one has normal insns that match
 738          cond_exec patterns, they will be preferred over these
 739          generated patterns.  Whether this matters in practice, or if
 740          it's a good thing, or whether we should thread these new
 741          patterns into the define_insn chain just after their generator
 742          is something we'll have to experiment with.  */
 743
 744       queue_pattern (insn, &other_tail, insn_elem->lineno);
 745     }
 746 }
 747
 748 /* If we have any DEFINE_COND_EXEC patterns, expand the DEFINE_INSN
 749    patterns appropriately.  */
 750
 751 static void
 752 process_define_cond_exec ()
 753 {
 754   struct queue_elem *elem;
 755
 756   identify_predicable_attribute ();
 757   if (errors)
 758     return;
 759
 760   for (elem = define_cond_exec_queue; elem ; elem = elem->next)
 761     process_one_cond_exec (elem);
 762 }
 763 \f
 764 /* The entry point for initializing the reader.  */
 765
 766 int
 767 init_md_reader (filename)
 768      const char *filename;
 769 {
 770   FILE *input_file;
 771   int c;
 772
 773   read_rtx_filename = filename;
 774   input_file = fopen (filename, "r");
 775   if (input_file == 0)
 776     {
 777       perror (filename);
 778       return FATAL_EXIT_CODE;
 779     }
 780
 781   obstack_init (rtl_obstack);
 782   errors = 0;
 783   sequence_num = 0;
 784
 785   /* Read the entire file.  */
 786   while (1)
 787     {
 788       rtx desc;
 789       int lineno;
 790
 791       c = read_skip_spaces (input_file);
 792       if (c == EOF)
 793         break;
 794
 795       ungetc (c, input_file);
 796       lineno = read_rtx_lineno;
 797       desc = read_rtx (input_file);
 798       process_rtx (desc, lineno);
 799     }
 800   fclose (input_file);
 801
 802   /* Process define_cond_exec patterns.  */
 803   if (define_cond_exec_queue != NULL)
 804     process_define_cond_exec ();
 805
 806   return errors ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE;
 807 }
 808
 809 /* The entry point for reading a single rtx from an md file.  */
 810
 811 rtx
 812 read_md_rtx (lineno, seqnr)
 813      int *lineno;
 814      int *seqnr;
 815 {
 816   struct queue_elem **queue, *elem;
 817   rtx desc;
 818
 819   /* Read all patterns from a given queue before moving on to the next.  */
 820   if (define_attr_queue != NULL)
 821     queue = &define_attr_queue;
 822   else if (define_insn_queue != NULL)
 823     queue = &define_insn_queue;
 824   else if (other_queue != NULL)
 825     queue = &other_queue;
 826   else
 827     return NULL_RTX;
 828
 829   elem = *queue;
 830   *queue = elem->next;
 831   desc = elem->data;
 832   *lineno = elem->lineno;
 833   *seqnr = sequence_num;
 834
 835   free (elem);
 836
 837   switch (GET_CODE (desc))
 838     {
 839     case DEFINE_INSN:
 840     case DEFINE_EXPAND:
 841     case DEFINE_SPLIT:
 842     case DEFINE_PEEPHOLE:
 843     case DEFINE_PEEPHOLE2:
 844       sequence_num++;
 845       break;
 846
 847     default:
 848       break;
 849     }
 850
 851   return desc;
 852 }
 853
 854 /* Until we can use the versions in libiberty.  */
 855 char *
 856 xstrdup (input)
 857   const char *input;
 858 {
 859   register size_t len = strlen (input) + 1;
 860   register char *output = xmalloc (len);
 861   memcpy (output, input, len);
 862   return output;
 863 }
 864
 865 PTR
 866 xrealloc (old, size)
 867   PTR old;
 868   size_t size;
 869 {
 870   register PTR ptr;
 871   if (old)
 872     ptr = (PTR) realloc (old, size);
 873   else
 874     ptr = (PTR) malloc (size);
 875   if (!ptr)
 876     fatal ("virtual memory exhausted");
 877   return ptr;
 878 }
 879
 880 PTR
 881 xmalloc (size)
 882   size_t size;
 883 {
 884   register PTR val = (PTR) malloc (size);
 885
 886   if (val == 0)
 887     fatal ("virtual memory exhausted");
 888   return val;
 889 }