gcc/fortran/data.c

   1 /* Supporting functions for resolving DATA statement.
   2    Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
   3    Free Software Foundation, Inc.
   4    Contributed by Lifang Zeng <zlf605@hotmail.com>
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  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 resolving 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 "system.h"
  38 #include "gfortran.h"
  39 #include "data.h"
  40 #include "constructor.h"
  41
  42 static void formalize_init_expr (gfc_expr *);
  43
  44 /* Calculate the array element offset.  */
  45
  46 static void
  47 get_array_index (gfc_array_ref *ar, mpz_t *offset)
  48 {
  49   gfc_expr *e;
  50   int i;
  51   mpz_t delta;
  52   mpz_t tmp;
  53
  54   mpz_init (tmp);
  55   mpz_set_si (*offset, 0);
  56   mpz_init_set_si (delta, 1);
  57   for (i = 0; i < ar->dimen; i++)
  58     {
  59       e = gfc_copy_expr (ar->start[i]);
  60       gfc_simplify_expr (e, 1);
  61
  62       if ((gfc_is_constant_expr (ar->as->lower[i]) == 0)
  63           || (gfc_is_constant_expr (ar->as->upper[i]) == 0)
  64           || (gfc_is_constant_expr (e) == 0))
  65         gfc_error ("non-constant array in DATA statement %L", &ar->where);
  66
  67       mpz_set (tmp, e->value.integer);
  68       mpz_sub (tmp, tmp, ar->as->lower[i]->value.integer);
  69       mpz_mul (tmp, tmp, delta);
  70       mpz_add (*offset, tmp, *offset);
  71
  72       mpz_sub (tmp, ar->as->upper[i]->value.integer,
  73                ar->as->lower[i]->value.integer);
  74       mpz_add_ui (tmp, tmp, 1);
  75       mpz_mul (delta, tmp, delta);
  76     }
  77   mpz_clear (delta);
  78   mpz_clear (tmp);
  79 }
  80
  81 /* Find if there is a constructor which component is equal to COM.
  82    TODO: remove this, use symbol.c(gfc_find_component) instead.  */
  83
  84 static gfc_constructor *
  85 find_con_by_component (gfc_component *com, gfc_constructor_base base)
  86 {
  87   gfc_constructor *c;
  88
  89   for (c = gfc_constructor_first (base); c; c = gfc_constructor_next (c))
  90     if (com == c->n.component)
  91       return c;
  92
  93   return NULL;
  94 }
  95
  96
  97 /* Create a character type initialization expression from RVALUE.
  98    TS [and REF] describe [the substring of] the variable being initialized.
  99    INIT is the existing initializer, not NULL.  Initialization is performed
 100    according to normal assignment rules.  */
 101
 102 static gfc_expr *
 103 create_character_initializer (gfc_expr *init, gfc_typespec *ts,
 104                               gfc_ref *ref, gfc_expr *rvalue)
 105 {
 106   int len, start, end;
 107   gfc_char_t *dest;
 108
 109   gfc_extract_int (ts->u.cl->length, &len);
 110
 111   if (init == NULL)
 112     {
 113       /* Create a new initializer.  */
 114       init = gfc_get_character_expr (ts->kind, NULL, NULL, len);
 115       init->ts = *ts;
 116     }
 117
 118   dest = init->value.character.string;
 119
 120   if (ref)
 121     {
 122       gfc_expr *start_expr, *end_expr;
 123
 124       gcc_assert (ref->type == REF_SUBSTRING);
 125
 126       /* Only set a substring of the destination.  Fortran substring bounds
 127          are one-based [start, end], we want zero based [start, end).  */
 128       start_expr = gfc_copy_expr (ref->u.ss.start);
 129       end_expr = gfc_copy_expr (ref->u.ss.end);
 130
 131       if ((gfc_simplify_expr (start_expr, 1) == FAILURE)
 132           || (gfc_simplify_expr (end_expr, 1)) == FAILURE)
 133         {
 134           gfc_error ("failure to simplify substring reference in DATA "
 135                      "statement at %L", &ref->u.ss.start->where);
 136           return NULL;
 137         }
 138
 139       gfc_extract_int (start_expr, &start);
 140       start--;
 141       gfc_extract_int (end_expr, &end);
 142     }
 143   else
 144     {
 145       /* Set the whole string.  */
 146       start = 0;
 147       end = len;
 148     }
 149
 150   /* Copy the initial value.  */
 151   if (rvalue->ts.type == BT_HOLLERITH)
 152     len = rvalue->representation.length - rvalue->ts.u.pad;
 153   else
 154     len = rvalue->value.character.length;
 155
 156   if (len > end - start)
 157     {
 158       gfc_warning_now ("Initialization string starting at %L was "
 159                        "truncated to fit the variable (%d/%d)",
 160                        &rvalue->where, end - start, len);
 161       len = end - start;
 162     }
 163
 164   if (rvalue->ts.type == BT_HOLLERITH)
 165     {
 166       int i;
 167       for (i = 0; i < len; i++)
 168         dest[start+i] = rvalue->representation.string[i];
 169     }
 170   else
 171     memcpy (&dest[start], rvalue->value.character.string,
 172             len * sizeof (gfc_char_t));
 173
 174   /* Pad with spaces.  Substrings will already be blanked.  */
 175   if (len < end - start && ref == NULL)
 176     gfc_wide_memset (&dest[start + len], ' ', end - (start + len));
 177
 178   if (rvalue->ts.type == BT_HOLLERITH)
 179     {
 180       init->representation.length = init->value.character.length;
 181       init->representation.string
 182         = gfc_widechar_to_char (init->value.character.string,
 183                                 init->value.character.length);
 184     }
 185
 186   return init;
 187 }
 188
 189
 190 /* Assign the initial value RVALUE to  LVALUE's symbol->value. If the
 191    LVALUE already has an initialization, we extend this, otherwise we
 192    create a new one.  */
 193
 194 gfc_try
 195 gfc_assign_data_value (gfc_expr *lvalue, gfc_expr *rvalue, mpz_t index)
 196 {
 197   gfc_ref *ref;
 198   gfc_expr *init;
 199   gfc_expr *expr;
 200   gfc_constructor *con;
 201   gfc_constructor *last_con;
 202   gfc_symbol *symbol;
 203   gfc_typespec *last_ts;
 204   mpz_t offset;
 205
 206   symbol = lvalue->symtree->n.sym;
 207   init = symbol->value;
 208   last_ts = &symbol->ts;
 209   last_con = NULL;
 210   mpz_init_set_si (offset, 0);
 211
 212   /* Find/create the parent expressions for subobject references.  */
 213   for (ref = lvalue->ref; ref; ref = ref->next)
 214     {
 215       /* Break out of the loop if we find a substring.  */
 216       if (ref->type == REF_SUBSTRING)
 217         {
 218           /* A substring should always be the last subobject reference.  */
 219           gcc_assert (ref->next == NULL);
 220           break;
 221         }
 222
 223       /* Use the existing initializer expression if it exists.  Otherwise
 224          create a new one.  */
 225       if (init == NULL)
 226         expr = gfc_get_expr ();
 227       else
 228         expr = init;
 229
 230       /* Find or create this element.  */
 231       switch (ref->type)
 232         {
 233         case REF_ARRAY:
 234           if (ref->u.ar.as->rank == 0)
 235             {
 236               gcc_assert (ref->u.ar.as->corank > 0);
 237               if (init == NULL)
 238                 gfc_free (expr);
 239               continue;
 240             }
 241
 242           if (init && expr->expr_type != EXPR_ARRAY)
 243             {
 244               gfc_error ("'%s' at %L already is initialized at %L",
 245                          lvalue->symtree->n.sym->name, &lvalue->where,
 246                          &init->where);
 247               goto abort;
 248             }
 249
 250           if (init == NULL)
 251             {
 252               /* The element typespec will be the same as the array
 253                  typespec.  */
 254               expr->ts = *last_ts;
 255               /* Setup the expression to hold the constructor.  */
 256               expr->expr_type = EXPR_ARRAY;
 257               expr->rank = ref->u.ar.as->rank;
 258             }
 259
 260           if (ref->u.ar.type == AR_ELEMENT)
 261             get_array_index (&ref->u.ar, &offset);
 262           else
 263             mpz_set (offset, index);
 264
 265           /* Check the bounds.  */
 266           if (mpz_cmp_si (offset, 0) < 0)
 267             {
 268               gfc_error ("Data element below array lower bound at %L",
 269                          &lvalue->where);
 270               goto abort;
 271             }
 272           else
 273             {
 274               mpz_t size;
 275               if (spec_size (ref->u.ar.as, &size) == SUCCESS)
 276                 {
 277                   if (mpz_cmp (offset, size) >= 0)
 278                     {
 279                       mpz_clear (size);
 280                       gfc_error ("Data element above array upper bound at %L",
 281                                  &lvalue->where);
 282                       goto abort;
 283                     }
 284                   mpz_clear (size);
 285                 }
 286             }
 287
 288           con = gfc_constructor_lookup (expr->value.constructor,
 289                                         mpz_get_si (offset));
 290           if (!con)
 291             {
 292               con = gfc_constructor_insert_expr (&expr->value.constructor,
 293                                                  NULL, &rvalue->where,
 294                                                  mpz_get_si (offset));
 295             }
 296           break;
 297
 298         case REF_COMPONENT:
 299           if (init == NULL)
 300             {
 301               /* Setup the expression to hold the constructor.  */
 302               expr->expr_type = EXPR_STRUCTURE;
 303               expr->ts.type = BT_DERIVED;
 304               expr->ts.u.derived = ref->u.c.sym;
 305             }
 306           else
 307             gcc_assert (expr->expr_type == EXPR_STRUCTURE);
 308           last_ts = &ref->u.c.component->ts;
 309
 310           /* Find the same element in the existing constructor.  */
 311           con = find_con_by_component (ref->u.c.component,
 312                                        expr->value.constructor);
 313
 314           if (con == NULL)
 315             {
 316               /* Create a new constructor.  */
 317               con = gfc_constructor_append_expr (&expr->value.constructor,
 318                                                  NULL, NULL);
 319               con->n.component = ref->u.c.component;
 320             }
 321           break;
 322
 323         default:
 324           gcc_unreachable ();
 325         }
 326
 327       if (init == NULL)
 328         {
 329           /* Point the container at the new expression.  */
 330           if (last_con == NULL)
 331             symbol->value = expr;
 332           else
 333             last_con->expr = expr;
 334         }
 335       init = con->expr;
 336       last_con = con;
 337     }
 338
 339   mpz_clear (offset);
 340
 341   if (ref || last_ts->type == BT_CHARACTER)
 342     {
 343       if (lvalue->ts.u.cl->length == NULL && !(ref && ref->u.ss.length != NULL))
 344         return FAILURE;
 345       expr = create_character_initializer (init, last_ts, ref, rvalue);
 346     }
 347   else
 348     {
 349       /* Overwriting an existing initializer is non-standard but usually only
 350          provokes a warning from other compilers.  */
 351       if (init != NULL)
 352         {
 353           /* Order in which the expressions arrive here depends on whether
 354              they are from data statements or F95 style declarations.
 355              Therefore, check which is the most recent.  */
 356           expr = (LOCATION_LINE (init->where.lb->location)
 357                   > LOCATION_LINE (rvalue->where.lb->location))
 358                ? init : rvalue;
 359           if (gfc_notify_std (GFC_STD_GNU,"Extension: "
 360                               "re-initialization of '%s' at %L",
 361                               symbol->name, &expr->where) == FAILURE)
 362             return FAILURE;
 363         }
 364
 365       expr = gfc_copy_expr (rvalue);
 366       if (!gfc_compare_types (&lvalue->ts, &expr->ts))
 367         gfc_convert_type (expr, &lvalue->ts, 0);
 368     }
 369
 370   if (last_con == NULL)
 371     symbol->value = expr;
 372   else
 373     last_con->expr = expr;
 374
 375   return SUCCESS;
 376
 377 abort:
 378   mpz_clear (offset);
 379   return FAILURE;
 380 }
 381
 382
 383 /* Similarly, but initialize REPEAT consecutive values in LVALUE the same
 384    value in RVALUE.  */
 385
 386 gfc_try
 387 gfc_assign_data_value_range (gfc_expr *lvalue, gfc_expr *rvalue,
 388                              mpz_t index, mpz_t repeat)
 389 {
 390   mpz_t offset, last_offset;
 391   gfc_try t;
 392
 393   mpz_init (offset);
 394   mpz_init (last_offset);
 395   mpz_add (last_offset, index, repeat);
 396
 397   t = SUCCESS;
 398   for (mpz_set(offset, index) ; mpz_cmp(offset, last_offset) < 0;
 399                    mpz_add_ui (offset, offset, 1))
 400     if (gfc_assign_data_value (lvalue, rvalue, offset) == FAILURE)
 401       {
 402         t = FAILURE;
 403         break;
 404       }
 405
 406   mpz_clear (offset);
 407   mpz_clear (last_offset);
 408
 409   return t;
 410 }
 411
 412
 413 /* Modify the index of array section and re-calculate the array offset.  */
 414
 415 void
 416 gfc_advance_section (mpz_t *section_index, gfc_array_ref *ar,
 417                      mpz_t *offset_ret)
 418 {
 419   int i;
 420   mpz_t delta;
 421   mpz_t tmp;
 422   bool forwards;
 423   int cmp;
 424
 425   for (i = 0; i < ar->dimen; i++)
 426     {
 427       if (ar->dimen_type[i] != DIMEN_RANGE)
 428         continue;
 429
 430       if (ar->stride[i])
 431         {
 432           mpz_add (section_index[i], section_index[i],
 433                    ar->stride[i]->value.integer);
 434         if (mpz_cmp_si (ar->stride[i]->value.integer, 0) >= 0)
 435           forwards = true;
 436         else
 437           forwards = false;
 438         }
 439       else
 440         {
 441           mpz_add_ui (section_index[i], section_index[i], 1);
 442           forwards = true;
 443         }
 444
 445       if (ar->end[i])
 446         cmp = mpz_cmp (section_index[i], ar->end[i]->value.integer);
 447       else
 448         cmp = mpz_cmp (section_index[i], ar->as->upper[i]->value.integer);
 449
 450       if ((cmp > 0 && forwards) || (cmp < 0 && !forwards))
 451         {
 452           /* Reset index to start, then loop to advance the next index.  */
 453           if (ar->start[i])
 454             mpz_set (section_index[i], ar->start[i]->value.integer);
 455           else
 456             mpz_set (section_index[i], ar->as->lower[i]->value.integer);
 457         }
 458       else
 459         break;
 460     }
 461
 462   mpz_set_si (*offset_ret, 0);
 463   mpz_init_set_si (delta, 1);
 464   mpz_init (tmp);
 465   for (i = 0; i < ar->dimen; i++)
 466     {
 467       mpz_sub (tmp, section_index[i], ar->as->lower[i]->value.integer);
 468       mpz_mul (tmp, tmp, delta);
 469       mpz_add (*offset_ret, tmp, *offset_ret);
 470
 471       mpz_sub (tmp, ar->as->upper[i]->value.integer,
 472                ar->as->lower[i]->value.integer);
 473       mpz_add_ui (tmp, tmp, 1);
 474       mpz_mul (delta, tmp, delta);
 475     }
 476   mpz_clear (tmp);
 477   mpz_clear (delta);
 478 }
 479
 480
 481 /* Rearrange a structure constructor so the elements are in the specified
 482    order.  Also insert NULL entries if necessary.  */
 483
 484 static void
 485 formalize_structure_cons (gfc_expr *expr)
 486 {
 487   gfc_constructor_base base = NULL;
 488   gfc_constructor *cur;
 489   gfc_component *order;
 490
 491   /* Constructor is already formalized.  */
 492   cur = gfc_constructor_first (expr->value.constructor);
 493   if (!cur || cur->n.component == NULL)
 494     return;
 495
 496   for (order = expr->ts.u.derived->components; order; order = order->next)
 497     {
 498       cur = find_con_by_component (order, expr->value.constructor);
 499       if (cur)
 500         gfc_constructor_append_expr (&base, cur->expr, &cur->expr->where);
 501       else
 502         gfc_constructor_append_expr (&base, NULL, NULL);
 503     }
 504
 505   /* For all what it's worth, one would expect
 506        gfc_constructor_free (expr->value.constructor);
 507      here. However, if the constructor is actually free'd,
 508      hell breaks loose in the testsuite?!  */
 509
 510   expr->value.constructor = base;
 511 }
 512
 513
 514 /* Make sure an initialization expression is in normalized form, i.e., all
 515    elements of the constructors are in the correct order.  */
 516
 517 static void
 518 formalize_init_expr (gfc_expr *expr)
 519 {
 520   expr_t type;
 521   gfc_constructor *c;
 522
 523   if (expr == NULL)
 524     return;
 525
 526   type = expr->expr_type;
 527   switch (type)
 528     {
 529     case EXPR_ARRAY:
 530       for (c = gfc_constructor_first (expr->value.constructor);
 531            c; c = gfc_constructor_next (c))
 532         formalize_init_expr (c->expr);
 533
 534     break;
 535
 536     case EXPR_STRUCTURE:
 537       formalize_structure_cons (expr);
 538       break;
 539
 540     default:
 541       break;
 542     }
 543 }
 544
 545
 546 /* Resolve symbol's initial value after all data statement.  */
 547
 548 void
 549 gfc_formalize_init_value (gfc_symbol *sym)
 550 {
 551   formalize_init_expr (sym->value);
 552 }
 553
 554
 555 /* Get the integer value into RET_AS and SECTION from AS and AR, and return
 556    offset.  */
 557
 558 void
 559 gfc_get_section_index (gfc_array_ref *ar, mpz_t *section_index, mpz_t *offset)
 560 {
 561   int i;
 562   mpz_t delta;
 563   mpz_t tmp;
 564
 565   mpz_set_si (*offset, 0);
 566   mpz_init (tmp);
 567   mpz_init_set_si (delta, 1);
 568   for (i = 0; i < ar->dimen; i++)
 569     {
 570       mpz_init (section_index[i]);
 571       switch (ar->dimen_type[i])
 572         {
 573         case DIMEN_ELEMENT:
 574         case DIMEN_RANGE:
 575           if (ar->start[i])
 576             {
 577               mpz_sub (tmp, ar->start[i]->value.integer,
 578                        ar->as->lower[i]->value.integer);
 579               mpz_mul (tmp, tmp, delta);
 580               mpz_add (*offset, tmp, *offset);
 581               mpz_set (section_index[i], ar->start[i]->value.integer);
 582             }
 583           else
 584               mpz_set (section_index[i], ar->as->lower[i]->value.integer);
 585           break;
 586
 587         case DIMEN_VECTOR:
 588           gfc_internal_error ("TODO: Vector sections in data statements");
 589
 590         default:
 591           gcc_unreachable ();
 592         }
 593
 594       mpz_sub (tmp, ar->as->upper[i]->value.integer,
 595                ar->as->lower[i]->value.integer);
 596       mpz_add_ui (tmp, tmp, 1);
 597       mpz_mul (delta, tmp, delta);
 598     }
 599
 600   mpz_clear (tmp);
 601   mpz_clear (delta);
 602 }
 603