gcc/gensupport.c

   1 /* Support routines for the various generation passes.
   2    Copyright (C) 2000, 2001 Free Software Foundation, Inc.
   3
   4    This file is part of GCC.
   5
   6    GCC is free software; you can redistribute it and/or modify it
   7    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    GCC is distributed in the hope that it will be useful, but WITHOUT
  12    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  13    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
  14    License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with GCC; see the file COPYING.  If not, write to the Free
  18    Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  19    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   VA_OPEN (ap, msg);
  83   VA_FIXEDARG (ap, int, lineno);
  84   VA_FIXEDARG (ap, const char *, msg);
  85
  86   fprintf (stderr, "%s:%d: ", read_rtx_filename, lineno);
  87   vfprintf (stderr, msg, ap);
  88   fputc ('\n', stderr);
  89
  90   VA_CLOSE (ap);
  91 }
  92 \f
  93 /* Queue PATTERN on LIST_TAIL.  */
  94
  95 static void
  96 queue_pattern (pattern, list_tail, lineno)
  97      rtx pattern;
  98      struct queue_elem ***list_tail;
  99      int lineno;
 100 {
 101   struct queue_elem *e = (struct queue_elem *) xmalloc (sizeof (*e));
 102   e->data = pattern;
 103   e->lineno = lineno;
 104   e->next = NULL;
 105   **list_tail = e;
 106   *list_tail = &e->next;
 107 }
 108
 109 /* Recursively remove constraints from an rtx.  */
 110
 111 static void
 112 remove_constraints (part)
 113      rtx part;
 114 {
 115   int i, j;
 116   const char *format_ptr;
 117
 118   if (part == 0)
 119     return;
 120
 121   if (GET_CODE (part) == MATCH_OPERAND)
 122     XSTR (part, 2) = "";
 123   else if (GET_CODE (part) == MATCH_SCRATCH)
 124     XSTR (part, 1) = "";
 125
 126   format_ptr = GET_RTX_FORMAT (GET_CODE (part));
 127
 128   for (i = 0; i < GET_RTX_LENGTH (GET_CODE (part)); i++)
 129     switch (*format_ptr++)
 130       {
 131       case 'e':
 132       case 'u':
 133         remove_constraints (XEXP (part, i));
 134         break;
 135       case 'E':
 136         if (XVEC (part, i) != NULL)
 137           for (j = 0; j < XVECLEN (part, i); j++)
 138             remove_constraints (XVECEXP (part, i, j));
 139         break;
 140       }
 141 }
 142
 143 /* Process a top level rtx in some way, queueing as appropriate.  */
 144
 145 static void
 146 process_rtx (desc, lineno)
 147      rtx desc;
 148      int lineno;
 149 {
 150   switch (GET_CODE (desc))
 151     {
 152     case DEFINE_INSN:
 153       queue_pattern (desc, &define_insn_tail, lineno);
 154       break;
 155
 156     case DEFINE_COND_EXEC:
 157       queue_pattern (desc, &define_cond_exec_tail, lineno);
 158       break;
 159
 160     case DEFINE_ATTR:
 161       queue_pattern (desc, &define_attr_tail, lineno);
 162       break;
 163
 164     case DEFINE_INSN_AND_SPLIT:
 165       {
 166         const char *split_cond;
 167         rtx split;
 168         rtvec attr;
 169         int i;
 170
 171         /* Create a split with values from the insn_and_split.  */
 172         split = rtx_alloc (DEFINE_SPLIT);
 173
 174         i = XVECLEN (desc, 1);
 175         XVEC (split, 0) = rtvec_alloc (i);
 176         while (--i >= 0)
 177           {
 178             XVECEXP (split, 0, i) = copy_rtx (XVECEXP (desc, 1, i));
 179             remove_constraints (XVECEXP (split, 0, i));
 180           }
 181
 182         /* If the split condition starts with "&&", append it to the
 183            insn condition to create the new split condition.  */
 184         split_cond = XSTR (desc, 4);
 185         if (split_cond[0] == '&' && split_cond[1] == '&')
 186           {
 187             const char *insn_cond = XSTR (desc, 2);
 188             size_t insn_cond_len = strlen (insn_cond);
 189             size_t split_cond_len = strlen (split_cond);
 190             char *combined;
 191
 192             combined = (char *) xmalloc (insn_cond_len + split_cond_len + 1);
 193             memcpy (combined, insn_cond, insn_cond_len);
 194             memcpy (combined + insn_cond_len, split_cond, split_cond_len + 1);
 195
 196             split_cond = combined;
 197           }
 198         XSTR (split, 1) = split_cond;
 199         XVEC (split, 2) = XVEC (desc, 5);
 200         XSTR (split, 3) = XSTR (desc, 6);
 201
 202         /* Fix up the DEFINE_INSN.  */
 203         attr = XVEC (desc, 7);
 204         PUT_CODE (desc, DEFINE_INSN);
 205         XVEC (desc, 4) = attr;
 206
 207         /* Queue them.  */
 208         queue_pattern (desc, &define_insn_tail, lineno);
 209         queue_pattern (split, &other_tail, lineno);
 210         break;
 211       }
 212
 213     default:
 214       queue_pattern (desc, &other_tail, lineno);
 215       break;
 216     }
 217 }
 218 \f
 219 /* Return true if attribute PREDICABLE is true for ELEM, which holds
 220    a DEFINE_INSN.  */
 221
 222 static int
 223 is_predicable (elem)
 224      struct queue_elem *elem;
 225 {
 226   rtvec vec = XVEC (elem->data, 4);
 227   const char *value;
 228   int i;
 229
 230   if (! vec)
 231     return predicable_default;
 232
 233   for (i = GET_NUM_ELEM (vec) - 1; i >= 0; --i)
 234     {
 235       rtx sub = RTVEC_ELT (vec, i);
 236       switch (GET_CODE (sub))
 237         {
 238         case SET_ATTR:
 239           if (strcmp (XSTR (sub, 0), "predicable") == 0)
 240             {
 241               value = XSTR (sub, 1);
 242               goto found;
 243             }
 244           break;
 245
 246         case SET_ATTR_ALTERNATIVE:
 247           if (strcmp (XSTR (sub, 0), "predicable") == 0)
 248             {
 249               message_with_line (elem->lineno,
 250                                  "multiple alternatives for `predicable'");
 251               errors = 1;
 252               return 0;
 253             }
 254           break;
 255
 256         case SET:
 257           if (GET_CODE (SET_DEST (sub)) != ATTR
 258               || strcmp (XSTR (SET_DEST (sub), 0), "predicable") != 0)
 259             break;
 260           sub = SET_SRC (sub);
 261           if (GET_CODE (sub) == CONST_STRING)
 262             {
 263               value = XSTR (sub, 0);
 264               goto found;
 265             }
 266
 267           /* ??? It would be possible to handle this if we really tried.
 268              It's not easy though, and I'm not going to bother until it
 269              really proves necessary.  */
 270           message_with_line (elem->lineno,
 271                              "non-constant value for `predicable'");
 272           errors = 1;
 273           return 0;
 274
 275         default:
 276           abort ();
 277         }
 278     }
 279
 280   return predicable_default;
 281
 282  found:
 283   /* Verify that predicability does not vary on the alternative.  */
 284   /* ??? It should be possible to handle this by simply eliminating
 285      the non-predicable alternatives from the insn.  FRV would like
 286      to do this.  Delay this until we've got the basics solid.  */
 287   if (strchr (value, ',') != NULL)
 288     {
 289       message_with_line (elem->lineno,
 290                          "multiple alternatives for `predicable'");
 291       errors = 1;
 292       return 0;
 293     }
 294
 295   /* Find out which value we're looking at.  */
 296   if (strcmp (value, predicable_true) == 0)
 297     return 1;
 298   if (strcmp (value, predicable_false) == 0)
 299     return 0;
 300
 301   message_with_line (elem->lineno,
 302                      "Unknown value `%s' for `predicable' attribute",
 303                      value);
 304   errors = 1;
 305   return 0;
 306 }
 307
 308 /* Examine the attribute "predicable"; discover its boolean values
 309    and its default.  */
 310
 311 static void
 312 identify_predicable_attribute ()
 313 {
 314   struct queue_elem *elem;
 315   char *p_true, *p_false;
 316   const char *value;
 317   size_t len;
 318
 319   /* Look for the DEFINE_ATTR for `predicable', which must exist.  */
 320   for (elem = define_attr_queue; elem ; elem = elem->next)
 321     if (strcmp (XSTR (elem->data, 0), "predicable") == 0)
 322       goto found;
 323
 324   message_with_line (define_cond_exec_queue->lineno,
 325                      "Attribute `predicable' not defined");
 326   errors = 1;
 327   return;
 328
 329  found:
 330   value = XSTR (elem->data, 1);
 331   len = strlen (value);
 332   p_false = (char *) xmalloc (len + 1);
 333   memcpy (p_false, value, len + 1);
 334
 335   p_true = strchr (p_false, ',');
 336   if (p_true == NULL || strchr (++p_true, ',') != NULL)
 337     {
 338       message_with_line (elem->lineno,
 339                          "Attribute `predicable' is not a boolean");
 340       errors = 1;
 341       return;
 342     }
 343   p_true[-1] = '\0';
 344
 345   predicable_true = p_true;
 346   predicable_false = p_false;
 347
 348   switch (GET_CODE (XEXP (elem->data, 2)))
 349     {
 350     case CONST_STRING:
 351       value = XSTR (XEXP (elem->data, 2), 0);
 352       break;
 353
 354     case CONST:
 355       message_with_line (elem->lineno,
 356                          "Attribute `predicable' cannot be const");
 357       errors = 1;
 358       return;
 359
 360     default:
 361       message_with_line (elem->lineno,
 362                          "Attribute `predicable' must have a constant default");
 363       errors = 1;
 364       return;
 365     }
 366
 367   if (strcmp (value, p_true) == 0)
 368     predicable_default = 1;
 369   else if (strcmp (value, p_false) == 0)
 370     predicable_default = 0;
 371   else
 372     {
 373       message_with_line (elem->lineno,
 374                          "Unknown value `%s' for `predicable' attribute",
 375                          value);
 376       errors = 1;
 377     }
 378 }
 379
 380 /* Return the number of alternatives in constraint S.  */
 381
 382 static int
 383 n_alternatives (s)
 384      const char *s;
 385 {
 386   int n = 1;
 387
 388   if (s)
 389     while (*s)
 390       n += (*s++ == ',');
 391
 392   return n;
 393 }
 394
 395 /* Determine how many alternatives there are in INSN, and how many
 396    operands.  */
 397
 398 static void
 399 collect_insn_data (pattern, palt, pmax)
 400      rtx pattern;
 401      int *palt, *pmax;
 402 {
 403   const char *fmt;
 404   enum rtx_code code;
 405   int i, j, len;
 406
 407   code = GET_CODE (pattern);
 408   switch (code)
 409     {
 410     case MATCH_OPERAND:
 411       i = n_alternatives (XSTR (pattern, 2));
 412       *palt = (i > *palt ? i : *palt);
 413       /* FALLTHRU */
 414
 415     case MATCH_OPERATOR:
 416     case MATCH_SCRATCH:
 417     case MATCH_PARALLEL:
 418     case MATCH_INSN:
 419       i = XINT (pattern, 0);
 420       if (i > *pmax)
 421         *pmax = i;
 422       break;
 423
 424     default:
 425       break;
 426     }
 427
 428   fmt = GET_RTX_FORMAT (code);
 429   len = GET_RTX_LENGTH (code);
 430   for (i = 0; i < len; i++)
 431     {
 432       switch (fmt[i])
 433         {
 434         case 'e': case 'u':
 435           collect_insn_data (XEXP (pattern, i), palt, pmax);
 436           break;
 437
 438         case 'V':
 439           if (XVEC (pattern, i) == NULL)
 440             break;
 441           /* FALLTHRU */
 442         case 'E':
 443           for (j = XVECLEN (pattern, i) - 1; j >= 0; --j)
 444             collect_insn_data (XVECEXP (pattern, i, j), palt, pmax);
 445           break;
 446
 447         case 'i': case 'w': case '0': case 's': case 'S': case 'T':
 448           break;
 449
 450         default:
 451           abort ();
 452         }
 453     }
 454 }
 455
 456 static rtx
 457 alter_predicate_for_insn (pattern, alt, max_op, lineno)
 458      rtx pattern;
 459      int alt, max_op, lineno;
 460 {
 461   const char *fmt;
 462   enum rtx_code code;
 463   int i, j, len;
 464
 465   code = GET_CODE (pattern);
 466   switch (code)
 467     {
 468     case MATCH_OPERAND:
 469       {
 470         const char *c = XSTR (pattern, 2);
 471
 472         if (n_alternatives (c) != 1)
 473           {
 474             message_with_line (lineno,
 475                                "Too many alternatives for operand %d",
 476                                XINT (pattern, 0));
 477             errors = 1;
 478             return NULL;
 479           }
 480
 481         /* Replicate C as needed to fill out ALT alternatives.  */
 482         if (c && *c && alt > 1)
 483           {
 484             size_t c_len = strlen (c);
 485             size_t len = alt * (c_len + 1);
 486             char *new_c = (char *) xmalloc (len);
 487
 488             memcpy (new_c, c, c_len);
 489             for (i = 1; i < alt; ++i)
 490               {
 491                 new_c[i * (c_len + 1) - 1] = ',';
 492                 memcpy (&new_c[i * (c_len + 1)], c, c_len);
 493               }
 494             new_c[len - 1] = '\0';
 495             XSTR (pattern, 2) = new_c;
 496           }
 497       }
 498       /* FALLTHRU */
 499
 500     case MATCH_OPERATOR:
 501     case MATCH_SCRATCH:
 502     case MATCH_PARALLEL:
 503     case MATCH_INSN:
 504       XINT (pattern, 0) += max_op;
 505       break;
 506
 507     default:
 508       break;
 509     }
 510
 511   fmt = GET_RTX_FORMAT (code);
 512   len = GET_RTX_LENGTH (code);
 513   for (i = 0; i < len; i++)
 514     {
 515       rtx r;
 516
 517       switch (fmt[i])
 518         {
 519         case 'e': case 'u':
 520           r = alter_predicate_for_insn (XEXP (pattern, i), alt,
 521                                         max_op, lineno);
 522           if (r == NULL)
 523             return r;
 524           break;
 525
 526         case 'E':
 527           for (j = XVECLEN (pattern, i) - 1; j >= 0; --j)
 528             {
 529               r = alter_predicate_for_insn (XVECEXP (pattern, i, j),
 530                                             alt, max_op, lineno);
 531               if (r == NULL)
 532                 return r;
 533             }
 534           break;
 535
 536         case 'i': case 'w': case '0': case 's':
 537           break;
 538
 539         default:
 540           abort ();
 541         }
 542     }
 543
 544   return pattern;
 545 }
 546
 547 static const char *
 548 alter_test_for_insn (ce_elem, insn_elem)
 549      struct queue_elem *ce_elem, *insn_elem;
 550 {
 551   const char *ce_test, *insn_test;
 552   char *new_test;
 553   size_t len, ce_len, insn_len;
 554
 555   ce_test = XSTR (ce_elem->data, 1);
 556   insn_test = XSTR (insn_elem->data, 2);
 557   if (!ce_test || *ce_test == '\0')
 558     return insn_test;
 559   if (!insn_test || *insn_test == '\0')
 560     return ce_test;
 561
 562   ce_len = strlen (ce_test);
 563   insn_len = strlen (insn_test);
 564   len = 1 + ce_len + 1 + 4 + 1 + insn_len + 1 + 1;
 565   new_test = (char *) xmalloc (len);
 566
 567   sprintf (new_test, "(%s) && (%s)", ce_test, insn_test);
 568
 569   return new_test;
 570 }
 571
 572 /* Adjust all of the operand numbers in OLD to match the shift they'll
 573    get from an operand displacement of DISP.  Return a pointer after the
 574    adjusted string.  */
 575
 576 static char *
 577 shift_output_template (new, old, disp)
 578      char *new;
 579      const char *old;
 580      int disp;
 581 {
 582   while (*old)
 583     {
 584       char c = *old++;
 585       *new++ = c;
 586       if (c == '%')
 587         {
 588           c = *old++;
 589           if (ISDIGIT ((unsigned char) c))
 590             c += disp;
 591           else if (ISUPPER ((unsigned char) c)
 592                    || ISLOWER ((unsigned char) c))
 593             {
 594               *new++ = c;
 595               c = *old++ + disp;
 596             }
 597           *new++ = c;
 598         }
 599     }
 600
 601   return new;
 602 }
 603
 604 static const char *
 605 alter_output_for_insn (ce_elem, insn_elem, alt, max_op)
 606      struct queue_elem *ce_elem, *insn_elem;
 607      int alt, max_op;
 608 {
 609   const char *ce_out, *insn_out;
 610   char *new, *p;
 611   size_t len, ce_len, insn_len;
 612
 613   /* ??? Could coordinate with genoutput to not duplicate code here.  */
 614
 615   ce_out = XSTR (ce_elem->data, 2);
 616   insn_out = XTMPL (insn_elem->data, 3);
 617   if (!ce_out || *ce_out == '\0')
 618     return insn_out;
 619
 620   ce_len = strlen (ce_out);
 621   insn_len = strlen (insn_out);
 622
 623   if (*insn_out == '*')
 624     /* You must take care of the predicate yourself.  */
 625     return insn_out;
 626
 627   if (*insn_out == '@')
 628     {
 629       len = (ce_len + 1) * alt + insn_len + 1;
 630       p = new = xmalloc (len);
 631
 632       do
 633         {
 634           do
 635             *p++ = *insn_out++;
 636           while (ISSPACE ((unsigned char) *insn_out));
 637
 638           if (*insn_out != '#')
 639             {
 640               p = shift_output_template (p, ce_out, max_op);
 641               *p++ = ' ';
 642             }
 643
 644           do
 645             *p++ = *insn_out++;
 646           while (*insn_out && *insn_out != '\n');
 647         }
 648       while (*insn_out);
 649       *p = '\0';
 650     }
 651   else
 652     {
 653       len = ce_len + 1 + insn_len + 1;
 654       new = xmalloc (len);
 655
 656       p = shift_output_template (new, ce_out, max_op);
 657       *p++ = ' ';
 658       memcpy (p, insn_out, insn_len + 1);
 659     }
 660
 661   return new;
 662 }
 663
 664 /* Replicate insns as appropriate for the given DEFINE_COND_EXEC.  */
 665
 666 static void
 667 process_one_cond_exec (ce_elem)
 668      struct queue_elem *ce_elem;
 669 {
 670   struct queue_elem *insn_elem;
 671   for (insn_elem = define_insn_queue; insn_elem ; insn_elem = insn_elem->next)
 672     {
 673       int alternatives, max_operand;
 674       rtx pred, insn, pattern;
 675
 676       if (! is_predicable (insn_elem))
 677         continue;
 678
 679       alternatives = 1;
 680       max_operand = -1;
 681       collect_insn_data (insn_elem->data, &alternatives, &max_operand);
 682       max_operand += 1;
 683
 684       if (XVECLEN (ce_elem->data, 0) != 1)
 685         {
 686           message_with_line (ce_elem->lineno,
 687                              "too many patterns in predicate");
 688           errors = 1;
 689           return;
 690         }
 691
 692       pred = copy_rtx (XVECEXP (ce_elem->data, 0, 0));
 693       pred = alter_predicate_for_insn (pred, alternatives, max_operand,
 694                                        ce_elem->lineno);
 695       if (pred == NULL)
 696         return;
 697
 698       /* Construct a new pattern for the new insn.  */
 699       insn = copy_rtx (insn_elem->data);
 700       XSTR (insn, 0) = "";
 701       pattern = rtx_alloc (COND_EXEC);
 702       XEXP (pattern, 0) = pred;
 703       if (XVECLEN (insn, 1) == 1)
 704         {
 705           XEXP (pattern, 1) = XVECEXP (insn, 1, 0);
 706           XVECEXP (insn, 1, 0) = pattern;
 707           PUT_NUM_ELEM (XVEC (insn, 1), 1);
 708         }
 709       else
 710         {
 711           XEXP (pattern, 1) = rtx_alloc (PARALLEL);
 712           XVEC (XEXP (pattern, 1), 0) = XVEC (insn, 1);
 713           XVEC (insn, 1) = rtvec_alloc (1);
 714           XVECEXP (insn, 1, 0) = pattern;
 715         }
 716
 717       XSTR (insn, 2) = alter_test_for_insn (ce_elem, insn_elem);
 718       XTMPL (insn, 3) = alter_output_for_insn (ce_elem, insn_elem,
 719                                               alternatives, max_operand);
 720
 721       /* ??? Set `predicable' to false.  Not crucial since it's really
 722          only used here, and we won't reprocess this new pattern.  */
 723
 724       /* Put the new pattern on the `other' list so that it
 725          (a) is not reprocessed by other define_cond_exec patterns
 726          (b) appears after all normal define_insn patterns.
 727
 728          ??? B is debatable.  If one has normal insns that match
 729          cond_exec patterns, they will be preferred over these
 730          generated patterns.  Whether this matters in practice, or if
 731          it's a good thing, or whether we should thread these new
 732          patterns into the define_insn chain just after their generator
 733          is something we'll have to experiment with.  */
 734
 735       queue_pattern (insn, &other_tail, insn_elem->lineno);
 736     }
 737 }
 738
 739 /* If we have any DEFINE_COND_EXEC patterns, expand the DEFINE_INSN
 740    patterns appropriately.  */
 741
 742 static void
 743 process_define_cond_exec ()
 744 {
 745   struct queue_elem *elem;
 746
 747   identify_predicable_attribute ();
 748   if (errors)
 749     return;
 750
 751   for (elem = define_cond_exec_queue; elem ; elem = elem->next)
 752     process_one_cond_exec (elem);
 753 }
 754 \f
 755 /* The entry point for initializing the reader.  */
 756
 757 int
 758 init_md_reader (filename)
 759      const char *filename;
 760 {
 761   FILE *input_file;
 762   int c;
 763
 764   read_rtx_filename = filename;
 765   input_file = fopen (filename, "r");
 766   if (input_file == 0)
 767     {
 768       perror (filename);
 769       return FATAL_EXIT_CODE;
 770     }
 771
 772   obstack_init (rtl_obstack);
 773   errors = 0;
 774   sequence_num = 0;
 775
 776   /* Read the entire file.  */
 777   while (1)
 778     {
 779       rtx desc;
 780       int lineno;
 781
 782       c = read_skip_spaces (input_file);
 783       if (c == EOF)
 784         break;
 785
 786       ungetc (c, input_file);
 787       lineno = read_rtx_lineno;
 788       desc = read_rtx (input_file);
 789       process_rtx (desc, lineno);
 790     }
 791   fclose (input_file);
 792
 793   /* Process define_cond_exec patterns.  */
 794   if (define_cond_exec_queue != NULL)
 795     process_define_cond_exec ();
 796
 797   return errors ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE;
 798 }
 799
 800 /* The entry point for reading a single rtx from an md file.  */
 801
 802 rtx
 803 read_md_rtx (lineno, seqnr)
 804      int *lineno;
 805      int *seqnr;
 806 {
 807   struct queue_elem **queue, *elem;
 808   rtx desc;
 809
 810   /* Read all patterns from a given queue before moving on to the next.  */
 811   if (define_attr_queue != NULL)
 812     queue = &define_attr_queue;
 813   else if (define_insn_queue != NULL)
 814     queue = &define_insn_queue;
 815   else if (other_queue != NULL)
 816     queue = &other_queue;
 817   else
 818     return NULL_RTX;
 819
 820   elem = *queue;
 821   *queue = elem->next;
 822   desc = elem->data;
 823   *lineno = elem->lineno;
 824   *seqnr = sequence_num;
 825
 826   free (elem);
 827
 828   switch (GET_CODE (desc))
 829     {
 830     case DEFINE_INSN:
 831     case DEFINE_EXPAND:
 832     case DEFINE_SPLIT:
 833     case DEFINE_PEEPHOLE:
 834     case DEFINE_PEEPHOLE2:
 835       sequence_num++;
 836       break;
 837
 838     default:
 839       break;
 840     }
 841
 842   return desc;
 843 }
 844
 845 /* Until we can use the versions in libiberty.  */
 846 char *
 847 xstrdup (input)
 848   const char *input;
 849 {
 850   size_t len = strlen (input) + 1;
 851   char *output = xmalloc (len);
 852   memcpy (output, input, len);
 853   return output;
 854 }
 855
 856 PTR
 857 xcalloc (nelem, elsize)
 858   size_t nelem, elsize;
 859 {
 860   PTR newmem;
 861
 862   if (nelem == 0 || elsize == 0)
 863     nelem = elsize = 1;
 864
 865   newmem = really_call_calloc (nelem, elsize);
 866   if (!newmem)
 867     fatal ("virtual memory exhausted");
 868   return (newmem);
 869 }
 870
 871 PTR
 872 xrealloc (old, size)
 873   PTR old;
 874   size_t size;
 875 {
 876   PTR ptr;
 877   if (old)
 878     ptr = (PTR) really_call_realloc (old, size);
 879   else
 880     ptr = (PTR) really_call_malloc (size);
 881   if (!ptr)
 882     fatal ("virtual memory exhausted");
 883   return ptr;
 884 }
 885
 886 PTR
 887 xmalloc (size)
 888   size_t size;
 889 {
 890   PTR val = (PTR) really_call_malloc (size);
 891
 892   if (val == 0)
 893     fatal ("virtual memory exhausted");
 894   return val;
 895 }