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   if (rvalue->ts.type == BT_HOLLERITH)
 196     init->from_H = 1;
 197
 198   return init;
 199 }
 200
 201 /* Assign the initial value RVALUE to  LVALUE's symbol->value. If the
 202    LVALUE already has an initialization, we extend this, otherwise we
 203    create a new one.  */
 204
 205 void
 206 gfc_assign_data_value (gfc_expr * lvalue, gfc_expr * rvalue, mpz_t index)
 207 {
 208   gfc_ref *ref;
 209   gfc_expr *init;
 210   gfc_expr *expr;
 211   gfc_constructor *con;
 212   gfc_constructor *last_con;
 213   gfc_symbol *symbol;
 214   gfc_typespec *last_ts;
 215   mpz_t offset;
 216
 217   symbol = lvalue->symtree->n.sym;
 218   init = symbol->value;
 219   last_ts = &symbol->ts;
 220   last_con = NULL;
 221   mpz_init_set_si (offset, 0);
 222
 223   /* Find/create the parent expressions for subobject references.  */
 224   for (ref = lvalue->ref; ref; ref = ref->next)
 225     {
 226       /* Break out of the loop if we find a substring.  */
 227       if (ref->type == REF_SUBSTRING)
 228         {
 229           /* A substring should always br the last subobject reference.  */
 230           gcc_assert (ref->next == NULL);
 231           break;
 232         }
 233
 234       /* Use the existing initializer expression if it exists.  Otherwise
 235          create a new one.  */
 236       if (init == NULL)
 237         expr = gfc_get_expr ();
 238       else
 239         expr = init;
 240
 241       /* Find or create this element.  */
 242       switch (ref->type)
 243         {
 244         case REF_ARRAY:
 245           if (init == NULL)
 246             {
 247               /* The element typespec will be the same as the array
 248                  typespec.  */
 249               expr->ts = *last_ts;
 250               /* Setup the expression to hold the constructor.  */
 251               expr->expr_type = EXPR_ARRAY;
 252               expr->rank = ref->u.ar.as->rank;
 253             }
 254           else
 255             gcc_assert (expr->expr_type == EXPR_ARRAY);
 256
 257           if (ref->u.ar.type == AR_ELEMENT)
 258             get_array_index (&ref->u.ar, &offset);
 259           else
 260             mpz_set (offset, index);
 261
 262           /* Find the same element in the existing constructor.  */
 263           con = expr->value.constructor;
 264           con = find_con_by_offset (offset, con);
 265
 266           if (con == NULL)
 267             {
 268               /* Create a new constructor.  */
 269               con = gfc_get_constructor ();
 270               mpz_set (con->n.offset, offset);
 271               gfc_insert_constructor (expr, con);
 272             }
 273           break;
 274
 275         case REF_COMPONENT:
 276           if (init == NULL)
 277             {
 278               /* Setup the expression to hold the constructor.  */
 279               expr->expr_type = EXPR_STRUCTURE;
 280               expr->ts.type = BT_DERIVED;
 281               expr->ts.derived = ref->u.c.sym;
 282             }
 283           else
 284             gcc_assert (expr->expr_type == EXPR_STRUCTURE);
 285           last_ts = &ref->u.c.component->ts;
 286
 287           /* Find the same element in the existing constructor.  */
 288           con = expr->value.constructor;
 289           con = find_con_by_component (ref->u.c.component, con);
 290
 291           if (con == NULL)
 292             {
 293               /* Create a new constructor.  */
 294               con = gfc_get_constructor ();
 295               con->n.component = ref->u.c.component;
 296               con->next = expr->value.constructor;
 297               expr->value.constructor = con;
 298             }
 299           break;
 300
 301         default:
 302           gcc_unreachable ();
 303         }
 304
 305       if (init == NULL)
 306         {
 307           /* Point the container at the new expression.  */
 308           if (last_con == NULL)
 309             symbol->value = expr;
 310           else
 311             last_con->expr = expr;
 312         }
 313       init = con->expr;
 314       last_con = con;
 315     }
 316
 317   if (ref || last_ts->type == BT_CHARACTER)
 318     expr = create_character_intializer (init, last_ts, ref, rvalue);
 319   else
 320     {
 321       /* Overwriting an existing initializer is non-standard but usually only
 322          provokes a warning from other compilers.  */
 323       if (init != NULL)
 324         {
 325           /* Order in which the expressions arrive here depends on whether they
 326              are from data statements or F95 style declarations. Therefore,
 327              check which is the most recent.  */
 328           expr = (init->where.lb->linenum > rvalue->where.lb->linenum) ?
 329                     init : rvalue;
 330           gfc_notify_std (GFC_STD_GNU, "Extension: re-initialization "
 331                           "of '%s' at %L",  symbol->name, &expr->where);
 332           return;
 333         }
 334
 335       expr = gfc_copy_expr (rvalue);
 336       if (!gfc_compare_types (&lvalue->ts, &expr->ts))
 337         gfc_convert_type (expr, &lvalue->ts, 0);
 338     }
 339
 340   if (last_con == NULL)
 341     symbol->value = expr;
 342   else
 343     last_con->expr = expr;
 344 }
 345
 346 /* Similarly, but initialize REPEAT consecutive values in LVALUE the same
 347    value in RVALUE.  For the nonce, LVALUE must refer to a full array, not
 348    an array section.  */
 349
 350 void
 351 gfc_assign_data_value_range (gfc_expr * lvalue, gfc_expr * rvalue,
 352                              mpz_t index, mpz_t repeat)
 353 {
 354   gfc_ref *ref;
 355   gfc_expr *init, *expr;
 356   gfc_constructor *con, *last_con;
 357   gfc_symbol *symbol;
 358   gfc_typespec *last_ts;
 359   mpz_t offset;
 360
 361   symbol = lvalue->symtree->n.sym;
 362   init = symbol->value;
 363   last_ts = &symbol->ts;
 364   last_con = NULL;
 365   mpz_init_set_si (offset, 0);
 366
 367   /* Find/create the parent expressions for subobject references.  */
 368   for (ref = lvalue->ref; ref; ref = ref->next)
 369     {
 370       /* Use the existing initializer expression if it exists.
 371          Otherwise create a new one.  */
 372       if (init == NULL)
 373         expr = gfc_get_expr ();
 374       else
 375         expr = init;
 376
 377       /* Find or create this element.  */
 378       switch (ref->type)
 379         {
 380         case REF_ARRAY:
 381           if (init == NULL)
 382             {
 383               /* The element typespec will be the same as the array
 384                  typespec.  */
 385               expr->ts = *last_ts;
 386               /* Setup the expression to hold the constructor.  */
 387               expr->expr_type = EXPR_ARRAY;
 388               expr->rank = ref->u.ar.as->rank;
 389             }
 390           else
 391             gcc_assert (expr->expr_type == EXPR_ARRAY);
 392
 393           if (ref->u.ar.type == AR_ELEMENT)
 394             {
 395               get_array_index (&ref->u.ar, &offset);
 396
 397               /* This had better not be the bottom of the reference.
 398                  We can still get to a full array via a component.  */
 399               gcc_assert (ref->next != NULL);
 400             }
 401           else
 402             {
 403               mpz_set (offset, index);
 404
 405               /* We're at a full array or an array section.  This means
 406                  that we've better have found a full array, and that we're
 407                  at the bottom of the reference.  */
 408               gcc_assert (ref->u.ar.type == AR_FULL);
 409               gcc_assert (ref->next == NULL);
 410             }
 411
 412           /* Find the same element in the existing constructor.  */
 413           con = expr->value.constructor;
 414           con = find_con_by_offset (offset, con);
 415
 416           /* Create a new constructor.  */
 417           if (con == NULL)
 418             {
 419               con = gfc_get_constructor ();
 420               mpz_set (con->n.offset, offset);
 421               if (ref->next == NULL)
 422                 mpz_set (con->repeat, repeat);
 423               gfc_insert_constructor (expr, con);
 424             }
 425           else
 426             gcc_assert (ref->next != NULL);
 427           break;
 428
 429         case REF_COMPONENT:
 430           if (init == NULL)
 431             {
 432               /* Setup the expression to hold the constructor.  */
 433               expr->expr_type = EXPR_STRUCTURE;
 434               expr->ts.type = BT_DERIVED;
 435               expr->ts.derived = ref->u.c.sym;
 436             }
 437           else
 438             gcc_assert (expr->expr_type == EXPR_STRUCTURE);
 439           last_ts = &ref->u.c.component->ts;
 440
 441           /* Find the same element in the existing constructor.  */
 442           con = expr->value.constructor;
 443           con = find_con_by_component (ref->u.c.component, con);
 444
 445           if (con == NULL)
 446             {
 447               /* Create a new constructor.  */
 448               con = gfc_get_constructor ();
 449               con->n.component = ref->u.c.component;
 450               con->next = expr->value.constructor;
 451               expr->value.constructor = con;
 452             }
 453
 454           /* Since we're only intending to initialize arrays here,
 455              there better be an inner reference.  */
 456           gcc_assert (ref->next != NULL);
 457           break;
 458
 459         case REF_SUBSTRING:
 460         default:
 461           gcc_unreachable ();
 462         }
 463
 464       if (init == NULL)
 465         {
 466           /* Point the container at the new expression.  */
 467           if (last_con == NULL)
 468             symbol->value = expr;
 469           else
 470             last_con->expr = expr;
 471         }
 472       init = con->expr;
 473       last_con = con;
 474     }
 475
 476   if (last_ts->type == BT_CHARACTER)
 477     expr = create_character_intializer (init, last_ts, NULL, rvalue);
 478   else
 479     {
 480       /* We should never be overwriting an existing initializer.  */
 481       gcc_assert (!init);
 482
 483       expr = gfc_copy_expr (rvalue);
 484       if (!gfc_compare_types (&lvalue->ts, &expr->ts))
 485         gfc_convert_type (expr, &lvalue->ts, 0);
 486     }
 487
 488   if (last_con == NULL)
 489     symbol->value = expr;
 490   else
 491     last_con->expr = expr;
 492 }
 493
 494 /* Modify the index of array section and re-calculate the array offset.  */
 495
 496 void
 497 gfc_advance_section (mpz_t *section_index, gfc_array_ref *ar,
 498                      mpz_t *offset_ret)
 499 {
 500   int i;
 501   mpz_t delta;
 502   mpz_t tmp;
 503   bool forwards;
 504   int cmp;
 505
 506   for (i = 0; i < ar->dimen; i++)
 507     {
 508       if (ar->dimen_type[i] != DIMEN_RANGE)
 509         continue;
 510
 511       if (ar->stride[i])
 512         {
 513           mpz_add (section_index[i], section_index[i],
 514                    ar->stride[i]->value.integer);
 515         if (mpz_cmp_si (ar->stride[i]->value.integer, 0) >= 0)
 516           forwards = true;
 517         else
 518           forwards = false;
 519         }
 520       else
 521         {
 522           mpz_add_ui (section_index[i], section_index[i], 1);
 523           forwards = true;
 524         }
 525
 526       if (ar->end[i])
 527         cmp = mpz_cmp (section_index[i], ar->end[i]->value.integer);
 528       else
 529         cmp = mpz_cmp (section_index[i], ar->as->upper[i]->value.integer);
 530
 531       if ((cmp > 0 && forwards)
 532           || (cmp < 0 && ! forwards))
 533         {
 534           /* Reset index to start, then loop to advance the next index.  */
 535           if (ar->start[i])
 536             mpz_set (section_index[i], ar->start[i]->value.integer);
 537           else
 538             mpz_set (section_index[i], ar->as->lower[i]->value.integer);
 539         }
 540       else
 541         break;
 542     }
 543
 544   mpz_set_si (*offset_ret, 0);
 545   mpz_init_set_si (delta, 1);
 546   mpz_init (tmp);
 547   for (i = 0; i < ar->dimen; i++)
 548     {
 549       mpz_sub (tmp, section_index[i], ar->as->lower[i]->value.integer);
 550       mpz_mul (tmp, tmp, delta);
 551       mpz_add (*offset_ret, tmp, *offset_ret);
 552
 553       mpz_sub (tmp, ar->as->upper[i]->value.integer,
 554                ar->as->lower[i]->value.integer);
 555       mpz_add_ui (tmp, tmp, 1);
 556       mpz_mul (delta, tmp, delta);
 557     }
 558   mpz_clear (tmp);
 559   mpz_clear (delta);
 560 }
 561
 562
 563 /* Rearrange a structure constructor so the elements are in the specified
 564    order.  Also insert NULL entries if necessary.  */
 565
 566 static void
 567 formalize_structure_cons (gfc_expr * expr)
 568 {
 569   gfc_constructor *head;
 570   gfc_constructor *tail;
 571   gfc_constructor *cur;
 572   gfc_constructor *last;
 573   gfc_constructor *c;
 574   gfc_component *order;
 575
 576   c = expr->value.constructor;
 577
 578   /* Constructor is already formalized.  */
 579   if (c->n.component == NULL)
 580     return;
 581
 582   head = tail = NULL;
 583   for (order = expr->ts.derived->components; order; order = order->next)
 584     {
 585       /* Find the next component.  */
 586       last = NULL;
 587       cur = c;
 588       while (cur != NULL && cur->n.component != order)
 589         {
 590           last = cur;
 591           cur = cur->next;
 592         }
 593
 594       if (cur == NULL)
 595         {
 596           /* Create a new one.  */
 597           cur = gfc_get_constructor ();
 598         }
 599       else
 600         {
 601           /* Remove it from the chain.  */
 602           if (last == NULL)
 603             c = cur->next;
 604           else
 605             last->next = cur->next;
 606           cur->next = NULL;
 607
 608           formalize_init_expr (cur->expr);
 609         }
 610
 611       /* Add it to the new constructor.  */
 612       if (head == NULL)
 613         head = tail = cur;
 614       else
 615         {
 616           tail->next = cur;
 617           tail = tail->next;
 618         }
 619     }
 620   gcc_assert (c == NULL);
 621   expr->value.constructor = head;
 622 }
 623
 624
 625 /* Make sure an initialization expression is in normalized form.  Ie. all
 626    elements of the constructors are in the correct order.  */
 627
 628 static void
 629 formalize_init_expr (gfc_expr * expr)
 630 {
 631   expr_t type;
 632   gfc_constructor *c;
 633
 634   if (expr == NULL)
 635     return;
 636
 637   type = expr->expr_type;
 638   switch (type)
 639     {
 640     case EXPR_ARRAY:
 641       c = expr->value.constructor;
 642       while (c)
 643         {
 644           formalize_init_expr (c->expr);
 645           c = c->next;
 646         }
 647       break;
 648
 649     case EXPR_STRUCTURE:
 650       formalize_structure_cons (expr);
 651       break;
 652
 653     default:
 654       break;
 655     }
 656 }
 657
 658
 659 /* Resolve symbol's initial value after all data statement.  */
 660
 661 void
 662 gfc_formalize_init_value (gfc_symbol *sym)
 663 {
 664   formalize_init_expr (sym->value);
 665 }
 666
 667
 668 /* Get the integer value into RET_AS and SECTION from AS and AR, and return
 669    offset.  */
 670
 671 void
 672 gfc_get_section_index (gfc_array_ref *ar, mpz_t *section_index, mpz_t *offset)
 673 {
 674   int i;
 675   mpz_t delta;
 676   mpz_t tmp;
 677
 678   mpz_set_si (*offset, 0);
 679   mpz_init (tmp);
 680   mpz_init_set_si (delta, 1);
 681   for (i = 0; i < ar->dimen; i++)
 682     {
 683       mpz_init (section_index[i]);
 684       switch (ar->dimen_type[i])
 685         {
 686         case DIMEN_ELEMENT:
 687         case DIMEN_RANGE:
 688           if (ar->start[i])
 689             {
 690               mpz_sub (tmp, ar->start[i]->value.integer,
 691                        ar->as->lower[i]->value.integer);
 692               mpz_mul (tmp, tmp, delta);
 693               mpz_add (*offset, tmp, *offset);
 694               mpz_set (section_index[i], ar->start[i]->value.integer);
 695             }
 696           else
 697               mpz_set (section_index[i], ar->as->lower[i]->value.integer);
 698           break;
 699
 700         case DIMEN_VECTOR:
 701           gfc_internal_error ("TODO: Vector sections in data statements");
 702
 703         default:
 704           gcc_unreachable ();
 705         }
 706
 707       mpz_sub (tmp, ar->as->upper[i]->value.integer,
 708                ar->as->lower[i]->value.integer);
 709       mpz_add_ui (tmp, tmp, 1);
 710       mpz_mul (delta, tmp, delta);
 711     }
 712
 713   mpz_clear (tmp);
 714   mpz_clear (delta);
 715 }
 716