gcc/fortran/data.c

   1 /* Supporting functions for resolving DATA statement.
   2    Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
   3    Contributed by Lifang Zeng <zlf605@hotmail.com>
   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, 51 Franklin Street, Fifth Floor,Boston, MA
  20 02110-1301, USA.  */
  21
  22
  23 /* Notes for DATA statement implementation:
  24
  25    We first assign initial value to each symbol by gfc_assign_data_value
  26    during resolveing DATA statement. Refer to check_data_variable and
  27    traverse_data_list in resolve.c.
  28
  29    The complexity exists in the handling of array section, implied do
  30    and array of struct appeared in DATA statement.
  31
  32    We call gfc_conv_structure, gfc_con_array_array_initializer,
  33    etc., to convert the initial value. Refer to trans-expr.c and
  34    trans-array.c.  */
  35
  36 #include "config.h"
  37 #include "gfortran.h"
  38
  39 static void formalize_init_expr (gfc_expr *);
  40
  41 /* Calculate the array element offset.  */
  42
  43 static void
  44 get_array_index (gfc_array_ref * ar, mpz_t * offset)
  45 {
  46   gfc_expr *e;
  47   int i;
  48   try re;
  49   mpz_t delta;
  50   mpz_t tmp;
  51
  52   mpz_init (tmp);
  53   mpz_set_si (*offset, 0);
  54   mpz_init_set_si (delta, 1);
  55   for (i = 0; i < ar->dimen; i++)
  56     {
  57       e = gfc_copy_expr (ar->start[i]);
  58       re = gfc_simplify_expr (e, 1);
  59
  60       if ((gfc_is_constant_expr (ar->as->lower[i]) == 0)
  61           || (gfc_is_constant_expr (ar->as->upper[i]) == 0)
  62           || (gfc_is_constant_expr (e) == 0))
  63         gfc_error ("non-constant array in DATA statement %L.", &ar->where);
  64       mpz_set (tmp, e->value.integer);
  65       mpz_sub (tmp, tmp, ar->as->lower[i]->value.integer);
  66       mpz_mul (tmp, tmp, delta);
  67       mpz_add (*offset, tmp, *offset);
  68
  69       mpz_sub (tmp, ar->as->upper[i]->value.integer,
  70       ar->as->lower[i]->value.integer);
  71       mpz_add_ui (tmp, tmp, 1);
  72       mpz_mul (delta, tmp, delta);
  73     }
  74   mpz_clear (delta);
  75   mpz_clear (tmp);
  76 }
  77
  78
  79 /* Find if there is a constructor which offset is equal to OFFSET.  */
  80
  81 static gfc_constructor *
  82 find_con_by_offset (mpz_t offset, gfc_constructor *con)
  83 {
  84   mpz_t tmp;
  85   gfc_constructor *ret = NULL;
  86
  87   mpz_init (tmp);
  88
  89   for (; con; con = con->next)
  90     {
  91       int cmp = mpz_cmp (offset, con->n.offset);
  92
  93       /* We retain a sorted list, so if we're too large, we're done.  */
  94       if (cmp < 0)
  95         break;
  96
  97       /* Yaye for exact matches.  */
  98       if (cmp == 0)
  99         {
 100           ret = con;
 101           break;
 102         }
 103
 104       /* If the constructor element is a range, match any element.  */
 105       if (mpz_cmp_ui (con->repeat, 1) > 0)
 106         {
 107           mpz_add (tmp, con->n.offset, con->repeat);
 108           if (mpz_cmp (offset, tmp) < 0)
 109             {
 110               ret = con;
 111               break;
 112             }
 113         }
 114     }
 115
 116   mpz_clear (tmp);
 117   return ret;
 118 }
 119
 120
 121 /* Find if there is a constructor which component is equal to COM.  */
 122
 123 static gfc_constructor *
 124 find_con_by_component (gfc_component *com, gfc_constructor *con)
 125 {
 126   for (; con; con = con->next)
 127     {
 128       if (com == con->n.component)
 129         return con;
 130     }
 131   return NULL;
 132 }
 133
 134
 135 /* Create a character type initialization expression from RVALUE.
 136    TS [and REF] describe [the substring of] the variable being initialized.
 137    INIT is thh existing initializer, not NULL.  Initialization is performed
 138    according to normal assignment rules.  */
 139
 140 static gfc_expr *
 141 create_character_intializer (gfc_expr * init, gfc_typespec * ts,
 142                              gfc_ref * ref, gfc_expr * rvalue)
 143 {
 144   int len;
 145   int start;
 146   int end;
 147   char *dest;
 148
 149   gfc_extract_int (ts->cl->length, &len);
 150
 151   if (init == NULL)
 152     {
 153       /* Create a new initializer.  */
 154       init = gfc_get_expr ();
 155       init->expr_type = EXPR_CONSTANT;
 156       init->ts = *ts;
 157
 158       dest = gfc_getmem (len);
 159       init->value.character.length = len;
 160       init->value.character.string = dest;
 161       /* Blank the string if we're only setting a substring.  */
 162       if (ref != NULL)
 163         memset (dest, ' ', len);
 164     }
 165   else
 166     dest = init->value.character.string;
 167
 168   if (ref)
 169     {
 170       gcc_assert (ref->type == REF_SUBSTRING);
 171
 172       /* Only set a substring of the destination.  Fortran substring bounds
 173          are one-based [start, end], we want zero based [start, end).  */
 174       gfc_extract_int (ref->u.ss.start, &start);
 175       start--;
 176       gfc_extract_int (ref->u.ss.end, &end);
 177     }
 178   else
 179     {
 180       /* Set the whole string.  */
 181       start = 0;
 182       end = len;
 183     }
 184
 185   /* Copy the initial value.  */
 186   len = rvalue->value.character.length;
 187   if (len > end - start)
 188     len = end - start;
 189   memcpy (&dest[start], rvalue->value.character.string, len);
 190
 191   /* Pad with spaces.  Substrings will already be blanked.  */
 192   if (len < end - start && ref == NULL)
 193     memset (&dest[start + len], ' ', end - (start + len));
 194
 195   return init;
 196 }
 197
 198 /* Assign the initial value RVALUE to  LVALUE's symbol->value. If the
 199    LVALUE already has an initialization, we extend this, otherwise we
 200    create a new one.  */
 201
 202 void
 203 gfc_assign_data_value (gfc_expr * lvalue, gfc_expr * rvalue, mpz_t index)
 204 {
 205   gfc_ref *ref;
 206   gfc_expr *init;
 207   gfc_expr *expr;
 208   gfc_constructor *con;
 209   gfc_constructor *last_con;
 210   gfc_symbol *symbol;
 211   gfc_typespec *last_ts;
 212   mpz_t offset;
 213
 214   symbol = lvalue->symtree->n.sym;
 215   init = symbol->value;
 216   last_ts = &symbol->ts;
 217   last_con = NULL;
 218   mpz_init_set_si (offset, 0);
 219
 220   /* Find/create the parent expressions for subobject references.  */
 221   for (ref = lvalue->ref; ref; ref = ref->next)
 222     {
 223       /* Break out of the loop if we find a substring.  */
 224       if (ref->type == REF_SUBSTRING)
 225         {
 226           /* A substring should always br the last subobject reference.  */
 227           gcc_assert (ref->next == NULL);
 228           break;
 229         }
 230
 231       /* Use the existing initializer expression if it exists.  Otherwise
 232          create a new one.  */
 233       if (init == NULL)
 234         expr = gfc_get_expr ();
 235       else
 236         expr = init;
 237
 238       /* Find or create this element.  */
 239       switch (ref->type)
 240         {
 241         case REF_ARRAY:
 242           if (init == NULL)
 243             {
 244               /* The element typespec will be the same as the array
 245                  typespec.  */
 246               expr->ts = *last_ts;
 247               /* Setup the expression to hold the constructor.  */
 248               expr->expr_type = EXPR_ARRAY;
 249               expr->rank = ref->u.ar.as->rank;
 250             }
 251           else
 252             gcc_assert (expr->expr_type == EXPR_ARRAY);
 253
 254           if (ref->u.ar.type == AR_ELEMENT)
 255             get_array_index (&ref->u.ar, &offset);
 256           else
 257             mpz_set (offset, index);
 258
 259           /* Find the same element in the existing constructor.  */
 260           con = expr->value.constructor;
 261           con = find_con_by_offset (offset, con);
 262
 263           if (con == NULL)
 264             {
 265               /* Create a new constructor.  */
 266               con = gfc_get_constructor ();
 267               mpz_set (con->n.offset, offset);
 268               gfc_insert_constructor (expr, con);
 269             }
 270           break;
 271
 272         case REF_COMPONENT:
 273           if (init == NULL)
 274             {
 275               /* Setup the expression to hold the constructor.  */
 276               expr->expr_type = EXPR_STRUCTURE;
 277               expr->ts.type = BT_DERIVED;
 278               expr->ts.derived = ref->u.c.sym;
 279             }
 280           else
 281             gcc_assert (expr->expr_type == EXPR_STRUCTURE);
 282           last_ts = &ref->u.c.component->ts;
 283
 284           /* Find the same element in the existing constructor.  */
 285           con = expr->value.constructor;
 286           con = find_con_by_component (ref->u.c.component, con);
 287
 288           if (con == NULL)
 289             {
 290               /* Create a new constructor.  */
 291               con = gfc_get_constructor ();
 292               con->n.component = ref->u.c.component;
 293               con->next = expr->value.constructor;
 294               expr->value.constructor = con;
 295             }
 296           break;
 297
 298         default:
 299           gcc_unreachable ();
 300         }
 301
 302       if (init == NULL)
 303         {
 304           /* Point the container at the new expression.  */
 305           if (last_con == NULL)
 306             symbol->value = expr;
 307           else
 308             last_con->expr = expr;
 309         }
 310       init = con->expr;
 311       last_con = con;
 312     }
 313
 314   if (ref || last_ts->type == BT_CHARACTER)
 315     expr = create_character_intializer (init, last_ts, ref, rvalue);
 316   else
 317     {
 318       /* Overwriting an existing initializer is non-standard but usually only
 319          provokes a warning from other compilers.  */
 320       if (init != NULL)
 321         {
 322           /* Order in which the expressions arrive here depends on whether they
 323              are from data statements or F95 style declarations. Therefore,
 324              check which is the most recent.  */
 325           expr = (init->where.lb->linenum > rvalue->where.lb->linenum) ?
 326                     init : rvalue;
 327           gfc_notify_std (GFC_STD_GNU, "Extension: re-initialization "
 328                           "of '%s' at %L",  symbol->name, &expr->where);
 329           return;
 330         }
 331
 332       expr = gfc_copy_expr (rvalue);
 333       if (!gfc_compare_types (&lvalue->ts, &expr->ts))
 334         gfc_convert_type (expr, &lvalue->ts, 0);
 335     }
 336
 337   if (last_con == NULL)
 338     symbol->value = expr;
 339   else
 340     last_con->expr = expr;
 341 }
 342
 343 /* Similarly, but initialize REPEAT consecutive values in LVALUE the same
 344    value in RVALUE.  For the nonce, LVALUE must refer to a full array, not
 345    an array section.  */
 346
 347 void
 348 gfc_assign_data_value_range (gfc_expr * lvalue, gfc_expr * rvalue,
 349                              mpz_t index, mpz_t repeat)
 350 {
 351   gfc_ref *ref;
 352   gfc_expr *init, *expr;
 353   gfc_constructor *con, *last_con;
 354   gfc_symbol *symbol;
 355   gfc_typespec *last_ts;
 356   mpz_t offset;
 357
 358   symbol = lvalue->symtree->n.sym;
 359   init = symbol->value;
 360   last_ts = &symbol->ts;
 361   last_con = NULL;
 362   mpz_init_set_si (offset, 0);
 363
 364   /* Find/create the parent expressions for subobject references.  */
 365   for (ref = lvalue->ref; ref; ref = ref->next)
 366     {
 367       /* Use the existing initializer expression if it exists.
 368          Otherwise create a new one.  */
 369       if (init == NULL)
 370         expr = gfc_get_expr ();
 371       else
 372         expr = init;
 373
 374       /* Find or create this element.  */
 375       switch (ref->type)
 376         {
 377         case REF_ARRAY:
 378           if (init == NULL)
 379             {
 380               /* The element typespec will be the same as the array
 381                  typespec.  */
 382               expr->ts = *last_ts;
 383               /* Setup the expression to hold the constructor.  */
 384               expr->expr_type = EXPR_ARRAY;
 385               expr->rank = ref->u.ar.as->rank;
 386             }
 387           else
 388             gcc_assert (expr->expr_type == EXPR_ARRAY);
 389
 390           if (ref->u.ar.type == AR_ELEMENT)
 391             {
 392               get_array_index (&ref->u.ar, &offset);
 393
 394               /* This had better not be the bottom of the reference.
 395                  We can still get to a full array via a component.  */
 396               gcc_assert (ref->next != NULL);
 397             }
 398           else
 399             {
 400               mpz_set (offset, index);
 401
 402               /* We're at a full array or an array section.  This means
 403                  that we've better have found a full array, and that we're
 404                  at the bottom of the reference.  */
 405               gcc_assert (ref->u.ar.type == AR_FULL);
 406               gcc_assert (ref->next == NULL);
 407             }
 408
 409           /* Find the same element in the existing constructor.  */
 410           con = expr->value.constructor;
 411           con = find_con_by_offset (offset, con);
 412
 413           /* Create a new constructor.  */
 414           if (con == NULL)
 415             {
 416               con = gfc_get_constructor ();
 417               mpz_set (con->n.offset, offset);
 418               if (ref->next == NULL)
 419                 mpz_set (con->repeat, repeat);
 420               gfc_insert_constructor (expr, con);
 421             }
 422           else
 423             gcc_assert (ref->next != NULL);
 424           break;
 425
 426         case REF_COMPONENT:
 427           if (init == NULL)
 428             {
 429               /* Setup the expression to hold the constructor.  */
 430               expr->expr_type = EXPR_STRUCTURE;
 431               expr->ts.type = BT_DERIVED;
 432               expr->ts.derived = ref->u.c.sym;
 433             }
 434           else
 435             gcc_assert (expr->expr_type == EXPR_STRUCTURE);
 436           last_ts = &ref->u.c.component->ts;
 437
 438           /* Find the same element in the existing constructor.  */
 439           con = expr->value.constructor;
 440           con = find_con_by_component (ref->u.c.component, con);
 441
 442           if (con == NULL)
 443             {
 444               /* Create a new constructor.  */
 445               con = gfc_get_constructor ();
 446               con->n.component = ref->u.c.component;
 447               con->next = expr->value.constructor;
 448               expr->value.constructor = con;
 449             }
 450
 451           /* Since we're only intending to initialize arrays here,
 452              there better be an inner reference.  */
 453           gcc_assert (ref->next != NULL);
 454           break;
 455
 456         case REF_SUBSTRING:
 457         default:
 458           gcc_unreachable ();
 459         }
 460
 461       if (init == NULL)
 462         {
 463           /* Point the container at the new expression.  */
 464           if (last_con == NULL)
 465             symbol->value = expr;
 466           else
 467             last_con->expr = expr;
 468         }
 469       init = con->expr;
 470       last_con = con;
 471     }
 472
 473   if (last_ts->type == BT_CHARACTER)
 474     expr = create_character_intializer (init, last_ts, NULL, rvalue);
 475   else
 476     {
 477       /* We should never be overwriting an existing initializer.  */
 478       gcc_assert (!init);
 479
 480       expr = gfc_copy_expr (rvalue);
 481       if (!gfc_compare_types (&lvalue->ts, &expr->ts))
 482         gfc_convert_type (expr, &lvalue->ts, 0);
 483     }
 484
 485   if (last_con == NULL)
 486     symbol->value = expr;
 487   else
 488     last_con->expr = expr;
 489 }
 490
 491 /* Modify the index of array section and re-calculate the array offset.  */
 492
 493 void
 494 gfc_advance_section (mpz_t *section_index, gfc_array_ref *ar,
 495                      mpz_t *offset_ret)
 496 {
 497   int i;
 498   mpz_t delta;
 499   mpz_t tmp;
 500   bool forwards;
 501   int cmp;
 502
 503   for (i = 0; i < ar->dimen; i++)
 504     {
 505       if (ar->dimen_type[i] != DIMEN_RANGE)
 506         continue;
 507
 508       if (ar->stride[i])
 509         {
 510           mpz_add (section_index[i], section_index[i],
 511                    ar->stride[i]->value.integer);
 512         if (mpz_cmp_si (ar->stride[i]->value.integer, 0) >= 0)
 513           forwards = true;
 514         else
 515           forwards = false;
 516         }
 517       else
 518         {
 519           mpz_add_ui (section_index[i], section_index[i], 1);
 520           forwards = true;
 521         }
 522
 523       if (ar->end[i])
 524         cmp = mpz_cmp (section_index[i], ar->end[i]->value.integer);
 525       else
 526         cmp = mpz_cmp (section_index[i], ar->as->upper[i]->value.integer);
 527
 528       if ((cmp > 0 && forwards)
 529           || (cmp < 0 && ! forwards))
 530         {
 531           /* Reset index to start, then loop to advance the next index.  */
 532           if (ar->start[i])
 533             mpz_set (section_index[i], ar->start[i]->value.integer);
 534           else
 535             mpz_set (section_index[i], ar->as->lower[i]->value.integer);
 536         }
 537       else
 538         break;
 539     }
 540
 541   mpz_set_si (*offset_ret, 0);
 542   mpz_init_set_si (delta, 1);
 543   mpz_init (tmp);
 544   for (i = 0; i < ar->dimen; i++)
 545     {
 546       mpz_sub (tmp, section_index[i], ar->as->lower[i]->value.integer);
 547       mpz_mul (tmp, tmp, delta);
 548       mpz_add (*offset_ret, tmp, *offset_ret);
 549
 550       mpz_sub (tmp, ar->as->upper[i]->value.integer,
 551                ar->as->lower[i]->value.integer);
 552       mpz_add_ui (tmp, tmp, 1);
 553       mpz_mul (delta, tmp, delta);
 554     }
 555   mpz_clear (tmp);
 556   mpz_clear (delta);
 557 }
 558
 559
 560 /* Rearrange a structure constructor so the elements are in the specified
 561    order.  Also insert NULL entries if necessary.  */
 562
 563 static void
 564 formalize_structure_cons (gfc_expr * expr)
 565 {
 566   gfc_constructor *head;
 567   gfc_constructor *tail;
 568   gfc_constructor *cur;
 569   gfc_constructor *last;
 570   gfc_constructor *c;
 571   gfc_component *order;
 572
 573   c = expr->value.constructor;
 574
 575   /* Constructor is already formalized.  */
 576   if (c->n.component == NULL)
 577     return;
 578
 579   head = tail = NULL;
 580   for (order = expr->ts.derived->components; order; order = order->next)
 581     {
 582       /* Find the next component.  */
 583       last = NULL;
 584       cur = c;
 585       while (cur != NULL && cur->n.component != order)
 586         {
 587           last = cur;
 588           cur = cur->next;
 589         }
 590
 591       if (cur == NULL)
 592         {
 593           /* Create a new one.  */
 594           cur = gfc_get_constructor ();
 595         }
 596       else
 597         {
 598           /* Remove it from the chain.  */
 599           if (last == NULL)
 600             c = cur->next;
 601           else
 602             last->next = cur->next;
 603           cur->next = NULL;
 604
 605           formalize_init_expr (cur->expr);
 606         }
 607
 608       /* Add it to the new constructor.  */
 609       if (head == NULL)
 610         head = tail = cur;
 611       else
 612         {
 613           tail->next = cur;
 614           tail = tail->next;
 615         }
 616     }
 617   gcc_assert (c == NULL);
 618   expr->value.constructor = head;
 619 }
 620
 621
 622 /* Make sure an initialization expression is in normalized form.  Ie. all
 623    elements of the constructors are in the correct order.  */
 624
 625 static void
 626 formalize_init_expr (gfc_expr * expr)
 627 {
 628   expr_t type;
 629   gfc_constructor *c;
 630
 631   if (expr == NULL)
 632     return;
 633
 634   type = expr->expr_type;
 635   switch (type)
 636     {
 637     case EXPR_ARRAY:
 638       c = expr->value.constructor;
 639       while (c)
 640         {
 641           formalize_init_expr (c->expr);
 642           c = c->next;
 643         }
 644       break;
 645
 646     case EXPR_STRUCTURE:
 647       formalize_structure_cons (expr);
 648       break;
 649
 650     default:
 651       break;
 652     }
 653 }
 654
 655
 656 /* Resolve symbol's initial value after all data statement.  */
 657
 658 void
 659 gfc_formalize_init_value (gfc_symbol *sym)
 660 {
 661   formalize_init_expr (sym->value);
 662 }
 663
 664
 665 /* Get the integer value into RET_AS and SECTION from AS and AR, and return
 666    offset.  */
 667
 668 void
 669 gfc_get_section_index (gfc_array_ref *ar, mpz_t *section_index, mpz_t *offset)
 670 {
 671   int i;
 672   mpz_t delta;
 673   mpz_t tmp;
 674
 675   mpz_set_si (*offset, 0);
 676   mpz_init (tmp);
 677   mpz_init_set_si (delta, 1);
 678   for (i = 0; i < ar->dimen; i++)
 679     {
 680       mpz_init (section_index[i]);
 681       switch (ar->dimen_type[i])
 682         {
 683         case DIMEN_ELEMENT:
 684         case DIMEN_RANGE:
 685           if (ar->start[i])
 686             {
 687               mpz_sub (tmp, ar->start[i]->value.integer,
 688                        ar->as->lower[i]->value.integer);
 689               mpz_mul (tmp, tmp, delta);
 690               mpz_add (*offset, tmp, *offset);
 691               mpz_set (section_index[i], ar->start[i]->value.integer);
 692             }
 693           else
 694               mpz_set (section_index[i], ar->as->lower[i]->value.integer);
 695           break;
 696
 697         case DIMEN_VECTOR:
 698           gfc_internal_error ("TODO: Vector sections in data statements");
 699
 700         default:
 701           gcc_unreachable ();
 702         }
 703
 704       mpz_sub (tmp, ar->as->upper[i]->value.integer,
 705                ar->as->lower[i]->value.integer);
 706       mpz_add_ui (tmp, tmp, 1);
 707       mpz_mul (delta, tmp, delta);
 708     }
 709
 710   mpz_clear (tmp);
 711   mpz_clear (delta);
 712 }
 713