gcc/fortran/array.c

   1 /* Array things
   2    Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc.
   3    Contributed by Andy Vaught
   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 #include "config.h"
  23 #include "gfortran.h"
  24 #include "match.h"
  25
  26 #include <string.h>
  27 #include <assert.h>
  28
  29 /* This parameter is the size of the largest array constructor that we
  30    will expand to an array constructor without iterators.
  31    Constructors larger than this will remain in the iterator form.  */
  32
  33 #define GFC_MAX_AC_EXPAND 100
  34
  35
  36 /**************** Array reference matching subroutines *****************/
  37
  38 /* Copy an array reference structure.  */
  39
  40 gfc_array_ref *
  41 gfc_copy_array_ref (gfc_array_ref * src)
  42 {
  43   gfc_array_ref *dest;
  44   int i;
  45
  46   if (src == NULL)
  47     return NULL;
  48
  49   dest = gfc_get_array_ref ();
  50
  51   *dest = *src;
  52
  53   for (i = 0; i < GFC_MAX_DIMENSIONS; i++)
  54     {
  55       dest->start[i] = gfc_copy_expr (src->start[i]);
  56       dest->end[i] = gfc_copy_expr (src->end[i]);
  57       dest->stride[i] = gfc_copy_expr (src->stride[i]);
  58     }
  59
  60   dest->offset = gfc_copy_expr (src->offset);
  61
  62   return dest;
  63 }
  64
  65
  66 /* Match a single dimension of an array reference.  This can be a
  67    single element or an array section.  Any modifications we've made
  68    to the ar structure are cleaned up by the caller.  If the init
  69    is set, we require the subscript to be a valid initialization
  70    expression.  */
  71
  72 static match
  73 match_subscript (gfc_array_ref * ar, int init)
  74 {
  75   match m;
  76   int i;
  77
  78   i = ar->dimen;
  79
  80   ar->c_where[i] = *gfc_current_locus ();
  81   ar->start[i] = ar->end[i] = ar->stride[i] = NULL;
  82
  83   /* We can't be sure of the difference between DIMEN_ELEMENT and
  84      DIMEN_VECTOR until we know the type of the element itself at
  85      resolution time.  */
  86
  87   ar->dimen_type[i] = DIMEN_UNKNOWN;
  88
  89   if (gfc_match_char (':') == MATCH_YES)
  90     goto end_element;
  91
  92   /* Get start element.  */
  93   if (init)
  94     m = gfc_match_init_expr (&ar->start[i]);
  95   else
  96     m = gfc_match_expr (&ar->start[i]);
  97
  98   if (m == MATCH_NO)
  99     gfc_error ("Expected array subscript at %C");
 100   if (m != MATCH_YES)
 101     return MATCH_ERROR;
 102
 103   if (gfc_match_char (':') == MATCH_NO)
 104     return MATCH_YES;
 105
 106   /* Get an optional end element.  Because we've seen the colon, we
 107      definitely have a range along this dimension.  */
 108 end_element:
 109   ar->dimen_type[i] = DIMEN_RANGE;
 110
 111   if (init)
 112     m = gfc_match_init_expr (&ar->end[i]);
 113   else
 114     m = gfc_match_expr (&ar->end[i]);
 115
 116   if (m == MATCH_ERROR)
 117     return MATCH_ERROR;
 118
 119   /* See if we have an optional stride.  */
 120   if (gfc_match_char (':') == MATCH_YES)
 121     {
 122       m = init ? gfc_match_init_expr (&ar->stride[i])
 123         : gfc_match_expr (&ar->stride[i]);
 124
 125       if (m == MATCH_NO)
 126         gfc_error ("Expected array subscript stride at %C");
 127       if (m != MATCH_YES)
 128         return MATCH_ERROR;
 129     }
 130
 131   return MATCH_YES;
 132 }
 133
 134
 135 /* Match an array reference, whether it is the whole array or a
 136    particular elements or a section. If init is set, the reference has
 137    to consist of init expressions.  */
 138
 139 match
 140 gfc_match_array_ref (gfc_array_ref * ar, gfc_array_spec * as, int init)
 141 {
 142   match m;
 143
 144   memset (ar, '\0', sizeof (ar));
 145
 146   ar->where = *gfc_current_locus ();
 147   ar->as = as;
 148
 149   if (gfc_match_char ('(') != MATCH_YES)
 150     {
 151       ar->type = AR_FULL;
 152       ar->dimen = 0;
 153       return MATCH_YES;
 154     }
 155
 156   ar->type = AR_UNKNOWN;
 157
 158   for (ar->dimen = 0; ar->dimen < GFC_MAX_DIMENSIONS; ar->dimen++)
 159     {
 160       m = match_subscript (ar, init);
 161       if (m == MATCH_ERROR)
 162         goto error;
 163
 164       if (gfc_match_char (')') == MATCH_YES)
 165         goto matched;
 166
 167       if (gfc_match_char (',') != MATCH_YES)
 168         {
 169           gfc_error ("Invalid form of array reference at %C");
 170           goto error;
 171         }
 172     }
 173
 174   gfc_error ("Array reference at %C cannot have more than "
 175              stringize (GFC_MAX_DIMENSIONS) " dimensions");
 176
 177 error:
 178   return MATCH_ERROR;
 179
 180 matched:
 181   ar->dimen++;
 182
 183   return MATCH_YES;
 184 }
 185
 186
 187 /************** Array specification matching subroutines ***************/
 188
 189 /* Free all of the expressions associated with array bounds
 190    specifications.  */
 191
 192 void
 193 gfc_free_array_spec (gfc_array_spec * as)
 194 {
 195   int i;
 196
 197   if (as == NULL)
 198     return;
 199
 200   for (i = 0; i < as->rank; i++)
 201     {
 202       gfc_free_expr (as->lower[i]);
 203       gfc_free_expr (as->upper[i]);
 204     }
 205
 206   gfc_free (as);
 207 }
 208
 209
 210 /* Take an array bound, resolves the expression, that make up the
 211    shape and check associated constraints.  */
 212
 213 static try
 214 resolve_array_bound (gfc_expr * e, int check_constant)
 215 {
 216
 217   if (e == NULL)
 218     return SUCCESS;
 219
 220   if (gfc_resolve_expr (e) == FAILURE
 221       || gfc_specification_expr (e) == FAILURE)
 222     return FAILURE;
 223
 224   if (check_constant && gfc_is_constant_expr (e) == 0)
 225     {
 226       gfc_error ("Variable '%s' at %L in this context must be constant",
 227                  e->symtree->n.sym->name, &e->where);
 228       return FAILURE;
 229     }
 230
 231   return SUCCESS;
 232 }
 233
 234
 235 /* Takes an array specification, resolves the expressions that make up
 236    the shape and make sure everything is integral.  */
 237
 238 try
 239 gfc_resolve_array_spec (gfc_array_spec * as, int check_constant)
 240 {
 241   gfc_expr *e;
 242   int i;
 243
 244   if (as == NULL)
 245     return SUCCESS;
 246
 247   for (i = 0; i < as->rank; i++)
 248     {
 249       e = as->lower[i];
 250       if (resolve_array_bound (e, check_constant) == FAILURE)
 251         return FAILURE;
 252
 253       e = as->upper[i];
 254       if (resolve_array_bound (e, check_constant) == FAILURE)
 255         return FAILURE;
 256     }
 257
 258   return SUCCESS;
 259 }
 260
 261
 262 /* Match a single array element specification.  The return values as
 263    well as the upper and lower bounds of the array spec are filled
 264    in according to what we see on the input.  The caller makes sure
 265    individual specifications make sense as a whole.
 266
 267
 268         Parsed       Lower   Upper  Returned
 269         ------------------------------------
 270           :          NULL    NULL   AS_DEFERRED (*)
 271           x           1       x     AS_EXPLICIT
 272           x:          x      NULL   AS_ASSUMED_SHAPE
 273           x:y         x       y     AS_EXPLICIT
 274           x:*         x      NULL   AS_ASSUMED_SIZE
 275           *           1      NULL   AS_ASSUMED_SIZE
 276
 277   (*) For non-pointer dummy arrays this is AS_ASSUMED_SHAPE.  This
 278   is fixed during the resolution of formal interfaces.
 279
 280    Anything else AS_UNKNOWN.  */
 281
 282 static array_type
 283 match_array_element_spec (gfc_array_spec * as)
 284 {
 285   gfc_expr **upper, **lower;
 286   match m;
 287
 288   lower = &as->lower[as->rank - 1];
 289   upper = &as->upper[as->rank - 1];
 290
 291   if (gfc_match_char ('*') == MATCH_YES)
 292     {
 293       *lower = gfc_int_expr (1);
 294       return AS_ASSUMED_SIZE;
 295     }
 296
 297   if (gfc_match_char (':') == MATCH_YES)
 298     return AS_DEFERRED;
 299
 300   m = gfc_match_expr (upper);
 301   if (m == MATCH_NO)
 302     gfc_error ("Expected expression in array specification at %C");
 303   if (m != MATCH_YES)
 304     return AS_UNKNOWN;
 305
 306   if (gfc_match_char (':') == MATCH_NO)
 307     {
 308       *lower = gfc_int_expr (1);
 309       return AS_EXPLICIT;
 310     }
 311
 312   *lower = *upper;
 313   *upper = NULL;
 314
 315   if (gfc_match_char ('*') == MATCH_YES)
 316     return AS_ASSUMED_SIZE;
 317
 318   m = gfc_match_expr (upper);
 319   if (m == MATCH_ERROR)
 320     return AS_UNKNOWN;
 321   if (m == MATCH_NO)
 322     return AS_ASSUMED_SHAPE;
 323
 324   return AS_EXPLICIT;
 325 }
 326
 327
 328 /* Matches an array specification, incidentally figuring out what sort
 329    it is.  */
 330
 331 match
 332 gfc_match_array_spec (gfc_array_spec ** asp)
 333 {
 334   array_type current_type;
 335   gfc_array_spec *as;
 336   int i;
 337
 338   if (gfc_match_char ('(') != MATCH_YES)
 339     {
 340       *asp = NULL;
 341       return MATCH_NO;
 342     }
 343
 344   as = gfc_get_array_spec ();
 345
 346   for (i = 0; i < GFC_MAX_DIMENSIONS; i++)
 347     {
 348       as->lower[i] = NULL;
 349       as->upper[i] = NULL;
 350     }
 351
 352   as->rank = 1;
 353
 354   for (;;)
 355     {
 356       current_type = match_array_element_spec (as);
 357
 358       if (as->rank == 1)
 359         {
 360           if (current_type == AS_UNKNOWN)
 361             goto cleanup;
 362           as->type = current_type;
 363         }
 364       else
 365         switch (as->type)
 366           {                     /* See how current spec meshes with the existing */
 367           case AS_UNKNOWN:
 368             goto cleanup;
 369
 370           case AS_EXPLICIT:
 371             if (current_type == AS_ASSUMED_SIZE)
 372               {
 373                 as->type = AS_ASSUMED_SIZE;
 374                 break;
 375               }
 376
 377             if (current_type == AS_EXPLICIT)
 378               break;
 379
 380             gfc_error
 381               ("Bad array specification for an explicitly shaped array"
 382                " at %C");
 383
 384             goto cleanup;
 385
 386           case AS_ASSUMED_SHAPE:
 387             if ((current_type == AS_ASSUMED_SHAPE)
 388                 || (current_type == AS_DEFERRED))
 389               break;
 390
 391             gfc_error
 392               ("Bad array specification for assumed shape array at %C");
 393             goto cleanup;
 394
 395           case AS_DEFERRED:
 396             if (current_type == AS_DEFERRED)
 397               break;
 398
 399             if (current_type == AS_ASSUMED_SHAPE)
 400               {
 401                 as->type = AS_ASSUMED_SHAPE;
 402                 break;
 403               }
 404
 405             gfc_error ("Bad specification for deferred shape array at %C");
 406             goto cleanup;
 407
 408           case AS_ASSUMED_SIZE:
 409             gfc_error ("Bad specification for assumed size array at %C");
 410             goto cleanup;
 411           }
 412
 413       if (gfc_match_char (')') == MATCH_YES)
 414         break;
 415
 416       if (gfc_match_char (',') != MATCH_YES)
 417         {
 418           gfc_error ("Expected another dimension in array declaration at %C");
 419           goto cleanup;
 420         }
 421
 422       if (as->rank >= GFC_MAX_DIMENSIONS)
 423         {
 424           gfc_error ("Array specification at %C has more than "
 425                      stringize (GFC_MAX_DIMENSIONS) " dimensions");
 426           goto cleanup;
 427         }
 428
 429       as->rank++;
 430     }
 431
 432   /* If a lower bounds of an assumed shape array is blank, put in one.  */
 433   if (as->type == AS_ASSUMED_SHAPE)
 434     {
 435       for (i = 0; i < as->rank; i++)
 436         {
 437           if (as->lower[i] == NULL)
 438             as->lower[i] = gfc_int_expr (1);
 439         }
 440     }
 441   *asp = as;
 442   return MATCH_YES;
 443
 444 cleanup:
 445   /* Something went wrong.  */
 446   gfc_free_array_spec (as);
 447   return MATCH_ERROR;
 448 }
 449
 450
 451 /* Given a symbol and an array specification, modify the symbol to
 452    have that array specification.  The error locus is needed in case
 453    something goes wrong.  On failure, the caller must free the spec.  */
 454
 455 try
 456 gfc_set_array_spec (gfc_symbol * sym, gfc_array_spec * as, locus * error_loc)
 457 {
 458
 459   if (as == NULL)
 460     return SUCCESS;
 461
 462   if (gfc_add_dimension (&sym->attr, error_loc) == FAILURE)
 463     return FAILURE;
 464
 465   sym->as = as;
 466
 467   return SUCCESS;
 468 }
 469
 470
 471 /* Copy an array specification.  */
 472
 473 gfc_array_spec *
 474 gfc_copy_array_spec (gfc_array_spec * src)
 475 {
 476   gfc_array_spec *dest;
 477   int i;
 478
 479   if (src == NULL)
 480     return NULL;
 481
 482   dest = gfc_get_array_spec ();
 483
 484   *dest = *src;
 485
 486   for (i = 0; i < dest->rank; i++)
 487     {
 488       dest->lower[i] = gfc_copy_expr (dest->lower[i]);
 489       dest->upper[i] = gfc_copy_expr (dest->upper[i]);
 490     }
 491
 492   return dest;
 493 }
 494
 495 /* Returns nonzero if the two expressions are equal.  Only handles integer
 496    constants.  */
 497
 498 static int
 499 compare_bounds (gfc_expr * bound1, gfc_expr * bound2)
 500 {
 501   if (bound1 == NULL || bound2 == NULL
 502       || bound1->expr_type != EXPR_CONSTANT
 503       || bound2->expr_type != EXPR_CONSTANT
 504       || bound1->ts.type != BT_INTEGER
 505       || bound2->ts.type != BT_INTEGER)
 506     gfc_internal_error ("gfc_compare_array_spec(): Array spec clobbered");
 507
 508   if (mpz_cmp (bound1->value.integer, bound2->value.integer) == 0)
 509     return 1;
 510   else
 511     return 0;
 512 }
 513
 514 /* Compares two array specifications.  They must be constant or deferred
 515    shape.  */
 516
 517 int
 518 gfc_compare_array_spec (gfc_array_spec * as1, gfc_array_spec * as2)
 519 {
 520   int i;
 521
 522   if (as1 == NULL && as2 == NULL)
 523     return 1;
 524
 525   if (as1 == NULL || as2 == NULL)
 526     return 0;
 527
 528   if (as1->rank != as2->rank)
 529     return 0;
 530
 531   if (as1->rank == 0)
 532     return 1;
 533
 534   if (as1->type != as2->type)
 535     return 0;
 536
 537   if (as1->type == AS_EXPLICIT)
 538     for (i = 0; i < as1->rank; i++)
 539       {
 540         if (compare_bounds (as1->lower[i], as2->lower[i]) == 0)
 541           return 0;
 542
 543         if (compare_bounds (as1->upper[i], as2->upper[i]) == 0)
 544           return 0;
 545       }
 546
 547   return 1;
 548 }
 549
 550
 551 /****************** Array constructor functions ******************/
 552
 553 /* Start an array constructor.  The constructor starts with zero
 554    elements and should be appended to by gfc_append_constructor().  */
 555
 556 gfc_expr *
 557 gfc_start_constructor (bt type, int kind, locus * where)
 558 {
 559   gfc_expr *result;
 560
 561   result = gfc_get_expr ();
 562
 563   result->expr_type = EXPR_ARRAY;
 564   result->rank = 1;
 565
 566   result->ts.type = type;
 567   result->ts.kind = kind;
 568   result->where = *where;
 569   return result;
 570 }
 571
 572
 573 /* Given an array constructor expression, append the new expression
 574    node onto the constructor.  */
 575
 576 void
 577 gfc_append_constructor (gfc_expr * base, gfc_expr * new)
 578 {
 579   gfc_constructor *c;
 580
 581   if (base->value.constructor == NULL)
 582     base->value.constructor = c = gfc_get_constructor ();
 583   else
 584     {
 585       c = base->value.constructor;
 586       while (c->next)
 587         c = c->next;
 588
 589       c->next = gfc_get_constructor ();
 590       c = c->next;
 591     }
 592
 593   c->expr = new;
 594
 595   if (new->ts.type != base->ts.type || new->ts.kind != base->ts.kind)
 596     gfc_internal_error ("gfc_append_constructor(): New node has wrong kind");
 597 }
 598
 599
 600 /* Given an array constructor expression, insert the new expression's
 601    constructor onto the base's one according to the offset.  */
 602
 603 void
 604 gfc_insert_constructor (gfc_expr * base, gfc_constructor * c1)
 605 {
 606   gfc_constructor *c, *pre;
 607   expr_t type;
 608
 609   type = base->expr_type;
 610
 611   if (base->value.constructor == NULL)
 612     base->value.constructor = c1;
 613   else
 614     {
 615       c = pre = base->value.constructor;
 616       while (c)
 617         {
 618           if (type == EXPR_ARRAY)
 619             {
 620               if (mpz_cmp (c->n.offset, c1->n.offset) < 0)
 621                 {
 622                   pre = c;
 623                   c = c->next;
 624                 }
 625               else if (mpz_cmp (c->n.offset, c1->n.offset) == 0)
 626                 {
 627                   gfc_error ("duplicated initializer");
 628                   break;
 629                 }
 630               else
 631                 break;
 632             }
 633           else
 634             {
 635               pre = c;
 636               c = c->next;
 637             }
 638         }
 639
 640       if (pre != c)
 641         {
 642           pre->next = c1;
 643           c1->next = c;
 644         }
 645       else
 646         {
 647           c1->next = c;
 648           base->value.constructor = c1;
 649         }
 650     }
 651 }
 652
 653
 654 /* Get a new constructor.  */
 655
 656 gfc_constructor *
 657 gfc_get_constructor (void)
 658 {
 659   gfc_constructor *c;
 660
 661   c = gfc_getmem (sizeof(gfc_constructor));
 662   c->expr = NULL;
 663   c->iterator = NULL;
 664   c->next = NULL;
 665   mpz_init_set_si (c->n.offset, 0);
 666   mpz_init_set_si (c->repeat, 0);
 667   return c;
 668 }
 669
 670
 671 /* Free chains of gfc_constructor structures.  */
 672
 673 void
 674 gfc_free_constructor (gfc_constructor * p)
 675 {
 676   gfc_constructor *next;
 677
 678   if (p == NULL)
 679     return;
 680
 681   for (; p; p = next)
 682     {
 683       next = p->next;
 684
 685       if (p->expr)
 686         gfc_free_expr (p->expr);
 687       if (p->iterator != NULL)
 688         gfc_free_iterator (p->iterator, 1);
 689       mpz_clear (p->n.offset);
 690       mpz_clear (p->repeat);
 691       gfc_free (p);
 692     }
 693 }
 694
 695
 696 /* Given an expression node that might be an array constructor and a
 697    symbol, make sure that no iterators in this or child constructors
 698    use the symbol as an implied-DO iterator.  Returns nonzero if a
 699    duplicate was found.  */
 700
 701 static int
 702 check_duplicate_iterator (gfc_constructor * c, gfc_symbol * master)
 703 {
 704   gfc_expr *e;
 705
 706   for (; c; c = c->next)
 707     {
 708       e = c->expr;
 709
 710       if (e->expr_type == EXPR_ARRAY
 711           && check_duplicate_iterator (e->value.constructor, master))
 712         return 1;
 713
 714       if (c->iterator == NULL)
 715         continue;
 716
 717       if (c->iterator->var->symtree->n.sym == master)
 718         {
 719           gfc_error
 720             ("DO-iterator '%s' at %L is inside iterator of the same name",
 721              master->name, &c->where);
 722
 723           return 1;
 724         }
 725     }
 726
 727   return 0;
 728 }
 729
 730
 731 /* Forward declaration because these functions are mutually recursive.  */
 732 static match match_array_cons_element (gfc_constructor **);
 733
 734 /* Match a list of array elements.  */
 735
 736 static match
 737 match_array_list (gfc_constructor ** result)
 738 {
 739   gfc_constructor *p, *head, *tail, *new;
 740   gfc_iterator iter;
 741   locus old_loc;
 742   gfc_expr *e;
 743   match m;
 744   int n;
 745
 746   old_loc = *gfc_current_locus ();
 747
 748   if (gfc_match_char ('(') == MATCH_NO)
 749     return MATCH_NO;
 750
 751   memset (&iter, '\0', sizeof (gfc_iterator));
 752   head = NULL;
 753
 754   m = match_array_cons_element (&head);
 755   if (m != MATCH_YES)
 756     goto cleanup;
 757
 758   tail = head;
 759
 760   if (gfc_match_char (',') != MATCH_YES)
 761     {
 762       m = MATCH_NO;
 763       goto cleanup;
 764     }
 765
 766   for (n = 1;; n++)
 767     {
 768       m = gfc_match_iterator (&iter, 0);
 769       if (m == MATCH_YES)
 770         break;
 771       if (m == MATCH_ERROR)
 772         goto cleanup;
 773
 774       m = match_array_cons_element (&new);
 775       if (m == MATCH_ERROR)
 776         goto cleanup;
 777       if (m == MATCH_NO)
 778         {
 779           if (n > 2)
 780             goto syntax;
 781           m = MATCH_NO;
 782           goto cleanup;         /* Could be a complex constant */
 783         }
 784
 785       tail->next = new;
 786       tail = new;
 787
 788       if (gfc_match_char (',') != MATCH_YES)
 789         {
 790           if (n > 2)
 791             goto syntax;
 792           m = MATCH_NO;
 793           goto cleanup;
 794         }
 795     }
 796
 797   if (gfc_match_char (')') != MATCH_YES)
 798     goto syntax;
 799
 800   if (check_duplicate_iterator (head, iter.var->symtree->n.sym))
 801     {
 802       m = MATCH_ERROR;
 803       goto cleanup;
 804     }
 805
 806   e = gfc_get_expr ();
 807   e->expr_type = EXPR_ARRAY;
 808   e->where = old_loc;
 809   e->value.constructor = head;
 810
 811   p = gfc_get_constructor ();
 812   p->where = *gfc_current_locus ();
 813   p->iterator = gfc_get_iterator ();
 814   *p->iterator = iter;
 815
 816   p->expr = e;
 817   *result = p;
 818
 819   return MATCH_YES;
 820
 821 syntax:
 822   gfc_error ("Syntax error in array constructor at %C");
 823   m = MATCH_ERROR;
 824
 825 cleanup:
 826   gfc_free_constructor (head);
 827   gfc_free_iterator (&iter, 0);
 828   gfc_set_locus (&old_loc);
 829   return m;
 830 }
 831
 832
 833 /* Match a single element of an array constructor, which can be a
 834    single expression or a list of elements.  */
 835
 836 static match
 837 match_array_cons_element (gfc_constructor ** result)
 838 {
 839   gfc_constructor *p;
 840   gfc_expr *expr;
 841   match m;
 842
 843   m = match_array_list (result);
 844   if (m != MATCH_NO)
 845     return m;
 846
 847   m = gfc_match_expr (&expr);
 848   if (m != MATCH_YES)
 849     return m;
 850
 851   p = gfc_get_constructor ();
 852   p->where = *gfc_current_locus ();
 853   p->expr = expr;
 854
 855   *result = p;
 856   return MATCH_YES;
 857 }
 858
 859
 860 /* Match an array constructor.  */
 861
 862 match
 863 gfc_match_array_constructor (gfc_expr ** result)
 864 {
 865   gfc_constructor *head, *tail, *new;
 866   gfc_expr *expr;
 867   locus where;
 868   match m;
 869
 870   if (gfc_match (" (/") == MATCH_NO)
 871     return MATCH_NO;
 872
 873   where = *gfc_current_locus ();
 874   head = tail = NULL;
 875
 876   if (gfc_match (" /)") == MATCH_YES)
 877     goto empty;                 /* Special case */
 878
 879   for (;;)
 880     {
 881       m = match_array_cons_element (&new);
 882       if (m == MATCH_ERROR)
 883         goto cleanup;
 884       if (m == MATCH_NO)
 885         goto syntax;
 886
 887       if (head == NULL)
 888         head = new;
 889       else
 890         tail->next = new;
 891
 892       tail = new;
 893
 894       if (gfc_match_char (',') == MATCH_NO)
 895         break;
 896     }
 897
 898   if (gfc_match (" /)") == MATCH_NO)
 899     goto syntax;
 900
 901 empty:
 902   expr = gfc_get_expr ();
 903
 904   expr->expr_type = EXPR_ARRAY;
 905
 906   expr->value.constructor = head;
 907   /* Size must be calculated at resolution time.  */
 908
 909   expr->where = where;
 910   expr->rank = 1;
 911
 912   *result = expr;
 913   return MATCH_YES;
 914
 915 syntax:
 916   gfc_error ("Syntax error in array constructor at %C");
 917
 918 cleanup:
 919   gfc_free_constructor (head);
 920   return MATCH_ERROR;
 921 }
 922
 923
 924
 925 /************** Check array constructors for correctness **************/
 926
 927 /* Given an expression, compare it's type with the type of the current
 928    constructor.  Returns nonzero if an error was issued.  The
 929    cons_state variable keeps track of whether the type of the
 930    constructor being read or resolved is known to be good, bad or just
 931    starting out.  */
 932
 933 static gfc_typespec constructor_ts;
 934 static enum
 935 { CONS_START, CONS_GOOD, CONS_BAD }
 936 cons_state;
 937
 938 static int
 939 check_element_type (gfc_expr * expr)
 940 {
 941
 942   if (cons_state == CONS_BAD)
 943     return 0;                   /* Supress further errors */
 944
 945   if (cons_state == CONS_START)
 946     {
 947       if (expr->ts.type == BT_UNKNOWN)
 948         cons_state = CONS_BAD;
 949       else
 950         {
 951           cons_state = CONS_GOOD;
 952           constructor_ts = expr->ts;
 953         }
 954
 955       return 0;
 956     }
 957
 958   if (gfc_compare_types (&constructor_ts, &expr->ts))
 959     return 0;
 960
 961   gfc_error ("Element in %s array constructor at %L is %s",
 962              gfc_typename (&constructor_ts), &expr->where,
 963              gfc_typename (&expr->ts));
 964
 965   cons_state = CONS_BAD;
 966   return 1;
 967 }
 968
 969
 970 /* Recursive work function for gfc_check_constructor_type(). */
 971
 972 static try
 973 check_constructor_type (gfc_constructor * c)
 974 {
 975   gfc_expr *e;
 976
 977   for (; c; c = c->next)
 978     {
 979       e = c->expr;
 980
 981       if (e->expr_type == EXPR_ARRAY)
 982         {
 983           if (check_constructor_type (e->value.constructor) == FAILURE)
 984             return FAILURE;
 985
 986           continue;
 987         }
 988
 989       if (check_element_type (e))
 990         return FAILURE;
 991     }
 992
 993   return SUCCESS;
 994 }
 995
 996
 997 /* Check that all elements of an array constructor are the same type.
 998    On FAILURE, an error has been generated.  */
 999
1000 try
1001 gfc_check_constructor_type (gfc_expr * e)
1002 {
1003   try t;
1004
1005   cons_state = CONS_START;
1006   gfc_clear_ts (&constructor_ts);
1007
1008   t = check_constructor_type (e->value.constructor);
1009   if (t == SUCCESS && e->ts.type == BT_UNKNOWN)
1010     e->ts = constructor_ts;
1011
1012   return t;
1013 }
1014
1015
1016
1017 typedef struct cons_stack
1018 {
1019   gfc_iterator *iterator;
1020   struct cons_stack *previous;
1021 }
1022 cons_stack;
1023
1024 static cons_stack *base;
1025
1026 static try check_constructor (gfc_constructor *, try (*)(gfc_expr *));
1027
1028 /* Check an EXPR_VARIABLE expression in a constructor to make sure
1029    that that variable is an iteration variables.  */
1030
1031 try
1032 gfc_check_iter_variable (gfc_expr * expr)
1033 {
1034
1035   gfc_symbol *sym;
1036   cons_stack *c;
1037
1038   sym = expr->symtree->n.sym;
1039
1040   for (c = base; c; c = c->previous)
1041     if (sym == c->iterator->var->symtree->n.sym)
1042       return SUCCESS;
1043
1044   return FAILURE;
1045 }
1046
1047
1048 /* Recursive work function for gfc_check_constructor().  This amounts
1049    to calling the check function for each expression in the
1050    constructor, giving variables with the names of iterators a pass.  */
1051
1052 static try
1053 check_constructor (gfc_constructor * c, try (*check_function) (gfc_expr *))
1054 {
1055   cons_stack element;
1056   gfc_expr *e;
1057   try t;
1058
1059   for (; c; c = c->next)
1060     {
1061       e = c->expr;
1062
1063       if (e->expr_type != EXPR_ARRAY)
1064         {
1065           if ((*check_function) (e) == FAILURE)
1066             return FAILURE;
1067           continue;
1068         }
1069
1070       element.previous = base;
1071       element.iterator = c->iterator;
1072
1073       base = &element;
1074       t = check_constructor (e->value.constructor, check_function);
1075       base = element.previous;
1076
1077       if (t == FAILURE)
1078         return FAILURE;
1079     }
1080
1081   /* Nothing went wrong, so all OK.  */
1082   return SUCCESS;
1083 }
1084
1085
1086 /* Checks a constructor to see if it is a particular kind of
1087    expression -- specification, restricted, or initialization as
1088    determined by the check_function.  */
1089
1090 try
1091 gfc_check_constructor (gfc_expr * expr, try (*check_function) (gfc_expr *))
1092 {
1093   cons_stack *base_save;
1094   try t;
1095
1096   base_save = base;
1097   base = NULL;
1098
1099   t = check_constructor (expr->value.constructor, check_function);
1100   base = base_save;
1101
1102   return t;
1103 }
1104
1105
1106
1107 /**************** Simplification of array constructors ****************/
1108
1109 iterator_stack *iter_stack;
1110
1111 typedef struct
1112 {
1113   gfc_constructor *new_head, *new_tail;
1114   int extract_count, extract_n;
1115   gfc_expr *extracted;
1116   mpz_t *count;
1117
1118   mpz_t *offset;
1119   gfc_component *component;
1120   mpz_t *repeat;
1121
1122   try (*expand_work_function) (gfc_expr *);
1123 }
1124 expand_info;
1125
1126 static expand_info current_expand;
1127
1128 static try expand_constructor (gfc_constructor *);
1129
1130
1131 /* Work function that counts the number of elements present in a
1132    constructor.  */
1133
1134 static try
1135 count_elements (gfc_expr * e)
1136 {
1137   mpz_t result;
1138
1139   if (e->rank == 0)
1140     mpz_add_ui (*current_expand.count, *current_expand.count, 1);
1141   else
1142     {
1143       if (gfc_array_size (e, &result) == FAILURE)
1144         {
1145           gfc_free_expr (e);
1146           return FAILURE;
1147         }
1148
1149       mpz_add (*current_expand.count, *current_expand.count, result);
1150       mpz_clear (result);
1151     }
1152
1153   gfc_free_expr (e);
1154   return SUCCESS;
1155 }
1156
1157
1158 /* Work function that extracts a particular element from an array
1159    constructor, freeing the rest.  */
1160
1161 static try
1162 extract_element (gfc_expr * e)
1163 {
1164
1165   if (e->rank != 0)
1166     {                           /* Something unextractable */
1167       gfc_free_expr (e);
1168       return FAILURE;
1169     }
1170
1171   if (current_expand.extract_count == current_expand.extract_n)
1172     current_expand.extracted = e;
1173   else
1174     gfc_free_expr (e);
1175
1176   current_expand.extract_count++;
1177   return SUCCESS;
1178 }
1179
1180
1181 /* Work function that constructs a new constructor out of the old one,
1182    stringing new elements together.  */
1183
1184 static try
1185 expand (gfc_expr * e)
1186 {
1187
1188   if (current_expand.new_head == NULL)
1189     current_expand.new_head = current_expand.new_tail =
1190       gfc_get_constructor ();
1191   else
1192     {
1193       current_expand.new_tail->next = gfc_get_constructor ();
1194       current_expand.new_tail = current_expand.new_tail->next;
1195     }
1196
1197   current_expand.new_tail->where = e->where;
1198   current_expand.new_tail->expr = e;
1199
1200   mpz_set (current_expand.new_tail->n.offset, *current_expand.offset);
1201   current_expand.new_tail->n.component = current_expand.component;
1202   mpz_set (current_expand.new_tail->repeat, *current_expand.repeat);
1203   return SUCCESS;
1204 }
1205
1206
1207 /* Given an initialization expression that is a variable reference,
1208    substitute the current value of the iteration variable.  */
1209
1210 void
1211 gfc_simplify_iterator_var (gfc_expr * e)
1212 {
1213   iterator_stack *p;
1214
1215   for (p = iter_stack; p; p = p->prev)
1216     if (e->symtree == p->variable)
1217       break;
1218
1219   if (p == NULL)
1220     return;             /* Variable not found */
1221
1222   gfc_replace_expr (e, gfc_int_expr (0));
1223
1224   mpz_set (e->value.integer, p->value);
1225
1226   return;
1227 }
1228
1229
1230 /* Expand an expression with that is inside of a constructor,
1231    recursing into other constructors if present.  */
1232
1233 static try
1234 expand_expr (gfc_expr * e)
1235 {
1236
1237   if (e->expr_type == EXPR_ARRAY)
1238     return expand_constructor (e->value.constructor);
1239
1240   e = gfc_copy_expr (e);
1241
1242   if (gfc_simplify_expr (e, 1) == FAILURE)
1243     {
1244       gfc_free_expr (e);
1245       return FAILURE;
1246     }
1247
1248   return current_expand.expand_work_function (e);
1249 }
1250
1251
1252 static try
1253 expand_iterator (gfc_constructor * c)
1254 {
1255   gfc_expr *start, *end, *step;
1256   iterator_stack frame;
1257   mpz_t trip;
1258   try t;
1259
1260   end = step = NULL;
1261
1262   t = FAILURE;
1263
1264   mpz_init (trip);
1265   mpz_init (frame.value);
1266
1267   start = gfc_copy_expr (c->iterator->start);
1268   if (gfc_simplify_expr (start, 1) == FAILURE)
1269     goto cleanup;
1270
1271   if (start->expr_type != EXPR_CONSTANT || start->ts.type != BT_INTEGER)
1272     goto cleanup;
1273
1274   end = gfc_copy_expr (c->iterator->end);
1275   if (gfc_simplify_expr (end, 1) == FAILURE)
1276     goto cleanup;
1277
1278   if (end->expr_type != EXPR_CONSTANT || end->ts.type != BT_INTEGER)
1279     goto cleanup;
1280
1281   step = gfc_copy_expr (c->iterator->step);
1282   if (gfc_simplify_expr (step, 1) == FAILURE)
1283     goto cleanup;
1284
1285   if (step->expr_type != EXPR_CONSTANT || step->ts.type != BT_INTEGER)
1286     goto cleanup;
1287
1288   if (mpz_sgn (step->value.integer) == 0)
1289     {
1290       gfc_error ("Iterator step at %L cannot be zero", &step->where);
1291       goto cleanup;
1292     }
1293
1294   /* Calculate the trip count of the loop.  */
1295   mpz_sub (trip, end->value.integer, start->value.integer);
1296   mpz_add (trip, trip, step->value.integer);
1297   mpz_tdiv_q (trip, trip, step->value.integer);
1298
1299   mpz_set (frame.value, start->value.integer);
1300
1301   frame.prev = iter_stack;
1302   frame.variable = c->iterator->var->symtree;
1303   iter_stack = &frame;
1304
1305   while (mpz_sgn (trip) > 0)
1306     {
1307       if (expand_expr (c->expr) == FAILURE)
1308         goto cleanup;
1309
1310       mpz_add (frame.value, frame.value, step->value.integer);
1311       mpz_sub_ui (trip, trip, 1);
1312     }
1313
1314   t = SUCCESS;
1315
1316 cleanup:
1317   gfc_free_expr (start);
1318   gfc_free_expr (end);
1319   gfc_free_expr (step);
1320
1321   mpz_clear (trip);
1322   mpz_clear (frame.value);
1323
1324   iter_stack = frame.prev;
1325
1326   return t;
1327 }
1328
1329
1330 /* Expand a constructor into constant constructors without any
1331    iterators, calling the work function for each of the expanded
1332    expressions.  The work function needs to either save or free the
1333    passed expression.  */
1334
1335 static try
1336 expand_constructor (gfc_constructor * c)
1337 {
1338   gfc_expr *e;
1339
1340   for (; c; c = c->next)
1341     {
1342       if (c->iterator != NULL)
1343         {
1344           if (expand_iterator (c) == FAILURE)
1345             return FAILURE;
1346           continue;
1347         }
1348
1349       e = c->expr;
1350
1351       if (e->expr_type == EXPR_ARRAY)
1352         {
1353           if (expand_constructor (e->value.constructor) == FAILURE)
1354             return FAILURE;
1355
1356           continue;
1357         }
1358
1359       e = gfc_copy_expr (e);
1360       if (gfc_simplify_expr (e, 1) == FAILURE)
1361         {
1362           gfc_free_expr (e);
1363           return FAILURE;
1364         }
1365       current_expand.offset = &c->n.offset;
1366       current_expand.component = c->n.component;
1367       current_expand.repeat = &c->repeat;
1368       if (current_expand.expand_work_function (e) == FAILURE)
1369         return FAILURE;
1370     }
1371   return SUCCESS;
1372 }
1373
1374
1375 /* Top level subroutine for expanding constructors.  We only expand
1376    constructor if they are small enough.  */
1377
1378 try
1379 gfc_expand_constructor (gfc_expr * e)
1380 {
1381   expand_info expand_save;
1382   gfc_expr *f;
1383   try rc;
1384
1385   f = gfc_get_array_element (e, GFC_MAX_AC_EXPAND);
1386   if (f != NULL)
1387     {
1388       gfc_free_expr (f);
1389       return SUCCESS;
1390     }
1391
1392   expand_save = current_expand;
1393   current_expand.new_head = current_expand.new_tail = NULL;
1394
1395   iter_stack = NULL;
1396
1397   current_expand.expand_work_function = expand;
1398
1399   if (expand_constructor (e->value.constructor) == FAILURE)
1400     {
1401       gfc_free_constructor (current_expand.new_head);
1402       rc = FAILURE;
1403       goto done;
1404     }
1405
1406   gfc_free_constructor (e->value.constructor);
1407   e->value.constructor = current_expand.new_head;
1408
1409   rc = SUCCESS;
1410
1411 done:
1412   current_expand = expand_save;
1413
1414   return rc;
1415 }
1416
1417
1418 /* Work function for checking that an element of a constructor is a
1419    constant, after removal of any iteration variables.  We return
1420    FAILURE if not so.  */
1421
1422 static try
1423 constant_element (gfc_expr * e)
1424 {
1425   int rv;
1426
1427   rv = gfc_is_constant_expr (e);
1428   gfc_free_expr (e);
1429
1430   return rv ? SUCCESS : FAILURE;
1431 }
1432
1433
1434 /* Given an array constructor, determine if the constructor is
1435    constant or not by expanding it and making sure that all elements
1436    are constants.  This is a bit of a hack since something like (/ (i,
1437    i=1,100000000) /) will take a while as* opposed to a more clever
1438    function that traverses the expression tree. FIXME.  */
1439
1440 int
1441 gfc_constant_ac (gfc_expr * e)
1442 {
1443   expand_info expand_save;
1444   try rc;
1445
1446   iter_stack = NULL;
1447   expand_save = current_expand;
1448   current_expand.expand_work_function = constant_element;
1449
1450   rc = expand_constructor (e->value.constructor);
1451
1452   current_expand = expand_save;
1453   if (rc == FAILURE)
1454     return 0;
1455
1456   return 1;
1457 }
1458
1459
1460 /* Returns nonzero if an array constructor has been completely
1461    expanded (no iterators) and zero if iterators are present.  */
1462
1463 int
1464 gfc_expanded_ac (gfc_expr * e)
1465 {
1466   gfc_constructor *p;
1467
1468   if (e->expr_type == EXPR_ARRAY)
1469     for (p = e->value.constructor; p; p = p->next)
1470       if (p->iterator != NULL || !gfc_expanded_ac (p->expr))
1471         return 0;
1472
1473   return 1;
1474 }
1475
1476
1477 /*************** Type resolution of array constructors ***************/
1478
1479 /* Recursive array list resolution function.  All of the elements must
1480    be of the same type.  */
1481
1482 static try
1483 resolve_array_list (gfc_constructor * p)
1484 {
1485   try t;
1486
1487   t = SUCCESS;
1488
1489   for (; p; p = p->next)
1490     {
1491       if (p->iterator != NULL
1492           && gfc_resolve_iterator (p->iterator) == FAILURE)
1493         t = FAILURE;
1494
1495       if (gfc_resolve_expr (p->expr) == FAILURE)
1496         t = FAILURE;
1497     }
1498
1499   return t;
1500 }
1501
1502
1503 /* Resolve all of the expressions in an array list.
1504    TODO: String lengths.  */
1505
1506 try
1507 gfc_resolve_array_constructor (gfc_expr * expr)
1508 {
1509   try t;
1510
1511   t = resolve_array_list (expr->value.constructor);
1512   if (t == SUCCESS)
1513     t = gfc_check_constructor_type (expr);
1514
1515   return t;
1516 }
1517
1518
1519 /* Copy an iterator structure.  */
1520
1521 static gfc_iterator *
1522 copy_iterator (gfc_iterator * src)
1523 {
1524   gfc_iterator *dest;
1525
1526   if (src == NULL)
1527     return NULL;
1528
1529   dest = gfc_get_iterator ();
1530
1531   dest->var = gfc_copy_expr (src->var);
1532   dest->start = gfc_copy_expr (src->start);
1533   dest->end = gfc_copy_expr (src->end);
1534   dest->step = gfc_copy_expr (src->step);
1535
1536   return dest;
1537 }
1538
1539
1540 /* Copy a constructor structure.  */
1541
1542 gfc_constructor *
1543 gfc_copy_constructor (gfc_constructor * src)
1544 {
1545   gfc_constructor *dest;
1546   gfc_constructor *tail;
1547
1548   if (src == NULL)
1549     return NULL;
1550
1551   dest = tail = NULL;
1552   while (src)
1553     {
1554       if (dest == NULL)
1555         dest = tail = gfc_get_constructor ();
1556       else
1557         {
1558           tail->next = gfc_get_constructor ();
1559           tail = tail->next;
1560         }
1561       tail->where = src->where;
1562       tail->expr = gfc_copy_expr (src->expr);
1563       tail->iterator = copy_iterator (src->iterator);
1564       mpz_set (tail->n.offset, src->n.offset);
1565       tail->n.component = src->n.component;
1566       mpz_set (tail->repeat, src->repeat);
1567       src = src->next;
1568     }
1569
1570   return dest;
1571 }
1572
1573
1574 /* Given an array expression and an element number (starting at zero),
1575    return a pointer to the array element.  NULL is returned if the
1576    size of the array has been exceeded.  The expression node returned
1577    remains a part of the array and should not be freed.  Access is not
1578    efficient at all, but this is another place where things do not
1579    have to be particularly fast.  */
1580
1581 gfc_expr *
1582 gfc_get_array_element (gfc_expr * array, int element)
1583 {
1584   expand_info expand_save;
1585   gfc_expr *e;
1586   try rc;
1587
1588   expand_save = current_expand;
1589   current_expand.extract_n = element;
1590   current_expand.expand_work_function = extract_element;
1591   current_expand.extracted = NULL;
1592   current_expand.extract_count = 0;
1593
1594   iter_stack = NULL;
1595
1596   rc = expand_constructor (array->value.constructor);
1597   e = current_expand.extracted;
1598   current_expand = expand_save;
1599
1600   if (rc == FAILURE)
1601     return NULL;
1602
1603   return e;
1604 }
1605
1606
1607 /********* Subroutines for determining the size of an array *********/
1608
1609 /* These are needed just to accomodate RESHAPE().  There are no
1610    diagnostics here, we just return a negative number if something
1611    goes wrong. */
1612
1613
1614 /* Get the size of single dimension of an array specification.  The
1615    array is guaranteed to be one dimensional.  */
1616
1617 static try
1618 spec_dimen_size (gfc_array_spec * as, int dimen, mpz_t * result)
1619 {
1620
1621   if (as == NULL)
1622     return FAILURE;
1623
1624   if (dimen < 0 || dimen > as->rank - 1)
1625     gfc_internal_error ("spec_dimen_size(): Bad dimension");
1626
1627   if (as->type != AS_EXPLICIT
1628       || as->lower[dimen]->expr_type != EXPR_CONSTANT
1629       || as->upper[dimen]->expr_type != EXPR_CONSTANT)
1630     return FAILURE;
1631
1632   mpz_init (*result);
1633
1634   mpz_sub (*result, as->upper[dimen]->value.integer,
1635            as->lower[dimen]->value.integer);
1636
1637   mpz_add_ui (*result, *result, 1);
1638
1639   return SUCCESS;
1640 }
1641
1642
1643 try
1644 spec_size (gfc_array_spec * as, mpz_t * result)
1645 {
1646   mpz_t size;
1647   int d;
1648
1649   mpz_init_set_ui (*result, 1);
1650
1651   for (d = 0; d < as->rank; d++)
1652     {
1653       if (spec_dimen_size (as, d, &size) == FAILURE)
1654         {
1655           mpz_clear (*result);
1656           return FAILURE;
1657         }
1658
1659       mpz_mul (*result, *result, size);
1660       mpz_clear (size);
1661     }
1662
1663   return SUCCESS;
1664 }
1665
1666
1667 /* Get the number of elements in an array section.  */
1668
1669 static try
1670 ref_dimen_size (gfc_array_ref * ar, int dimen, mpz_t * result)
1671 {
1672   mpz_t upper, lower, stride;
1673   try t;
1674
1675   if (dimen < 0 || ar == NULL || dimen > ar->dimen - 1)
1676     gfc_internal_error ("ref_dimen_size(): Bad dimension");
1677
1678   switch (ar->dimen_type[dimen])
1679     {
1680     case DIMEN_ELEMENT:
1681       mpz_init (*result);
1682       mpz_set_ui (*result, 1);
1683       t = SUCCESS;
1684       break;
1685
1686     case DIMEN_VECTOR:
1687       t = gfc_array_size (ar->start[dimen], result);    /* Recurse! */
1688       break;
1689
1690     case DIMEN_RANGE:
1691       mpz_init (upper);
1692       mpz_init (lower);
1693       mpz_init (stride);
1694       t = FAILURE;
1695
1696       if (ar->start[dimen] == NULL)
1697         {
1698           if (ar->as->lower[dimen] == NULL
1699               || ar->as->lower[dimen]->expr_type != EXPR_CONSTANT)
1700             goto cleanup;
1701           mpz_set (lower, ar->as->lower[dimen]->value.integer);
1702         }
1703       else
1704         {
1705           if (ar->start[dimen]->expr_type != EXPR_CONSTANT)
1706             goto cleanup;
1707           mpz_set (lower, ar->start[dimen]->value.integer);
1708         }
1709
1710       if (ar->end[dimen] == NULL)
1711         {
1712           if (ar->as->upper[dimen] == NULL
1713               || ar->as->upper[dimen]->expr_type != EXPR_CONSTANT)
1714             goto cleanup;
1715           mpz_set (upper, ar->as->upper[dimen]->value.integer);
1716         }
1717       else
1718         {
1719           if (ar->end[dimen]->expr_type != EXPR_CONSTANT)
1720             goto cleanup;
1721           mpz_set (upper, ar->end[dimen]->value.integer);
1722         }
1723
1724       if (ar->stride[dimen] == NULL)
1725         mpz_set_ui (stride, 1);
1726       else
1727         {
1728           if (ar->stride[dimen]->expr_type != EXPR_CONSTANT)
1729             goto cleanup;
1730           mpz_set (stride, ar->stride[dimen]->value.integer);
1731         }
1732
1733       mpz_init (*result);
1734       mpz_sub (*result, upper, lower);
1735       mpz_add (*result, *result, stride);
1736       mpz_div (*result, *result, stride);
1737
1738       /* Zero stride caught earlier.  */
1739       if (mpz_cmp_ui (*result, 0) < 0)
1740         mpz_set_ui (*result, 0);
1741       t = SUCCESS;
1742
1743     cleanup:
1744       mpz_clear (upper);
1745       mpz_clear (lower);
1746       mpz_clear (stride);
1747       return t;
1748
1749     default:
1750       gfc_internal_error ("ref_dimen_size(): Bad dimen_type");
1751     }
1752
1753   return t;
1754 }
1755
1756
1757 static try
1758 ref_size (gfc_array_ref * ar, mpz_t * result)
1759 {
1760   mpz_t size;
1761   int d;
1762
1763   mpz_init_set_ui (*result, 1);
1764
1765   for (d = 0; d < ar->dimen; d++)
1766     {
1767       if (ref_dimen_size (ar, d, &size) == FAILURE)
1768         {
1769           mpz_clear (*result);
1770           return FAILURE;
1771         }
1772
1773       mpz_mul (*result, *result, size);
1774       mpz_clear (size);
1775     }
1776
1777   return SUCCESS;
1778 }
1779
1780
1781 /* Given an array expression and a dimension, figure out how many
1782    elements it has along that dimension.  Returns SUCCESS if we were
1783    able to return a result in the 'result' variable, FAILURE
1784    otherwise.  */
1785
1786 try
1787 gfc_array_dimen_size (gfc_expr * array, int dimen, mpz_t * result)
1788 {
1789   gfc_ref *ref;
1790   int i;
1791
1792   if (dimen < 0 || array == NULL || dimen > array->rank - 1)
1793     gfc_internal_error ("gfc_array_dimen_size(): Bad dimension");
1794
1795   switch (array->expr_type)
1796     {
1797     case EXPR_VARIABLE:
1798     case EXPR_FUNCTION:
1799       for (ref = array->ref; ref; ref = ref->next)
1800         {
1801           if (ref->type != REF_ARRAY)
1802             continue;
1803
1804           if (ref->u.ar.type == AR_FULL)
1805             return spec_dimen_size (ref->u.ar.as, dimen, result);
1806
1807           if (ref->u.ar.type == AR_SECTION)
1808             {
1809               for (i = 0; dimen >= 0; i++)
1810                 if (ref->u.ar.dimen_type[i] != DIMEN_ELEMENT)
1811                   dimen--;
1812
1813               return ref_dimen_size (&ref->u.ar, i - 1, result);
1814             }
1815         }
1816
1817       if (spec_dimen_size (array->symtree->n.sym->as, dimen, result) == FAILURE)
1818         return FAILURE;
1819
1820       break;
1821
1822     case EXPR_ARRAY:
1823       if (array->shape == NULL) {
1824         /* Expressions with rank > 1 should have "shape" properly set */
1825         if ( array->rank != 1 )
1826           gfc_internal_error ("gfc_array_dimen_size(): Bad EXPR_ARRAY expr");
1827         return gfc_array_size(array, result);
1828       }
1829
1830       /* Fall through */
1831     default:
1832       if (array->shape == NULL)
1833         return FAILURE;
1834
1835       mpz_init_set (*result, array->shape[dimen]);
1836
1837       break;
1838     }
1839
1840   return SUCCESS;
1841 }
1842
1843
1844 /* Given an array expression, figure out how many elements are in the
1845    array.  Returns SUCCESS if this is possible, and sets the 'result'
1846    variable.  Otherwise returns FAILURE.  */
1847
1848 try
1849 gfc_array_size (gfc_expr * array, mpz_t * result)
1850 {
1851   expand_info expand_save;
1852   gfc_ref *ref;
1853   int i, flag;
1854   try t;
1855
1856   switch (array->expr_type)
1857     {
1858     case EXPR_ARRAY:
1859       flag = gfc_suppress_error;
1860       gfc_suppress_error = 1;
1861
1862       expand_save = current_expand;
1863
1864       current_expand.count = result;
1865       mpz_init_set_ui (*result, 0);
1866
1867       current_expand.expand_work_function = count_elements;
1868       iter_stack = NULL;
1869
1870       t = expand_constructor (array->value.constructor);
1871       gfc_suppress_error = flag;
1872
1873       if (t == FAILURE)
1874         mpz_clear (*result);
1875       current_expand = expand_save;
1876       return t;
1877
1878     case EXPR_VARIABLE:
1879       for (ref = array->ref; ref; ref = ref->next)
1880         {
1881           if (ref->type != REF_ARRAY)
1882             continue;
1883
1884           if (ref->u.ar.type == AR_FULL)
1885             return spec_size (ref->u.ar.as, result);
1886
1887           if (ref->u.ar.type == AR_SECTION)
1888             return ref_size (&ref->u.ar, result);
1889         }
1890
1891       return spec_size (array->symtree->n.sym->as, result);
1892
1893
1894     default:
1895       if (array->rank == 0 || array->shape == NULL)
1896         return FAILURE;
1897
1898       mpz_init_set_ui (*result, 1);
1899
1900       for (i = 0; i < array->rank; i++)
1901         mpz_mul (*result, *result, array->shape[i]);
1902
1903       break;
1904     }
1905
1906   return SUCCESS;
1907 }
1908
1909
1910 /* Given an array reference, return the shape of the reference in an
1911    array of mpz_t integers.  */
1912
1913 try
1914 gfc_array_ref_shape (gfc_array_ref * ar, mpz_t * shape)
1915 {
1916   int d;
1917   int i;
1918
1919   d = 0;
1920
1921   switch (ar->type)
1922     {
1923     case AR_FULL:
1924       for (; d < ar->as->rank; d++)
1925         if (spec_dimen_size (ar->as, d, &shape[d]) == FAILURE)
1926           goto cleanup;
1927
1928       return SUCCESS;
1929
1930     case AR_SECTION:
1931       for (i = 0; i < ar->dimen; i++)
1932         {
1933           if (ar->dimen_type[i] != DIMEN_ELEMENT)
1934             {
1935               if (ref_dimen_size (ar, i, &shape[d]) == FAILURE)
1936                 goto cleanup;
1937               d++;
1938             }
1939         }
1940
1941       return SUCCESS;
1942
1943     default:
1944       break;
1945     }
1946
1947 cleanup:
1948   for (d--; d >= 0; d--)
1949     mpz_clear (shape[d]);
1950
1951   return FAILURE;
1952 }
1953
1954
1955 /* Given an array expression, find the array reference structure that
1956    characterizes the reference.  */
1957
1958 gfc_array_ref *
1959 gfc_find_array_ref (gfc_expr * e)
1960 {
1961   gfc_ref *ref;
1962
1963   for (ref = e->ref; ref; ref = ref->next)
1964     if (ref->type == REF_ARRAY
1965         && (ref->u.ar.type == AR_FULL
1966             || ref->u.ar.type == AR_SECTION))
1967       break;
1968
1969   if (ref == NULL)
1970     gfc_internal_error ("gfc_find_array_ref(): No ref found");
1971
1972   return &ref->u.ar;
1973 }