gcc/fortran/target-memory.c

   1 /* Simulate storage of variables into target memory.
   2    Copyright (C) 2007, 2008
   3    Free Software Foundation, Inc.
   4    Contributed by Paul Thomas and Brooks Moses
   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 #include "config.h"
  23 #include "system.h"
  24 #include "flags.h"
  25 #include "machmode.h"
  26 #include "tree.h"
  27 #include "gfortran.h"
  28 #include "arith.h"
  29 #include "trans.h"
  30 #include "trans-const.h"
  31 #include "trans-types.h"
  32 #include "target-memory.h"
  33
  34 /* --------------------------------------------------------------- */
  35 /* Calculate the size of an expression.  */
  36
  37 static size_t
  38 size_array (gfc_expr *e)
  39 {
  40   mpz_t array_size;
  41   size_t elt_size = gfc_target_expr_size (e->value.constructor->expr);
  42
  43   gfc_array_size (e, &array_size);
  44   return (size_t)mpz_get_ui (array_size) * elt_size;
  45 }
  46
  47 static size_t
  48 size_integer (int kind)
  49 {
  50   return GET_MODE_SIZE (TYPE_MODE (gfc_get_int_type (kind)));;
  51 }
  52
  53
  54 static size_t
  55 size_float (int kind)
  56 {
  57   return GET_MODE_SIZE (TYPE_MODE (gfc_get_real_type (kind)));;
  58 }
  59
  60
  61 static size_t
  62 size_complex (int kind)
  63 {
  64   return 2 * size_float (kind);
  65 }
  66
  67
  68 static size_t
  69 size_logical (int kind)
  70 {
  71   return GET_MODE_SIZE (TYPE_MODE (gfc_get_logical_type (kind)));;
  72 }
  73
  74
  75 static size_t
  76 size_character (int length, int kind)
  77 {
  78   return length * kind;
  79 }
  80
  81
  82 size_t
  83 gfc_target_expr_size (gfc_expr *e)
  84 {
  85   tree type;
  86
  87   gcc_assert (e != NULL);
  88
  89   if (e->expr_type == EXPR_ARRAY)
  90     return size_array (e);
  91
  92   switch (e->ts.type)
  93     {
  94     case BT_INTEGER:
  95       return size_integer (e->ts.kind);
  96     case BT_REAL:
  97       return size_float (e->ts.kind);
  98     case BT_COMPLEX:
  99       return size_complex (e->ts.kind);
 100     case BT_LOGICAL:
 101       return size_logical (e->ts.kind);
 102     case BT_CHARACTER:
 103       if (e->expr_type == EXPR_SUBSTRING && e->ref)
 104         {
 105           int start, end;
 106
 107           gfc_extract_int (e->ref->u.ss.start, &start);
 108           gfc_extract_int (e->ref->u.ss.end, &end);
 109           return size_character (MAX(end - start + 1, 0), e->ts.kind);
 110         }
 111       else
 112         return size_character (e->value.character.length, e->ts.kind);
 113     case BT_HOLLERITH:
 114       return e->representation.length;
 115     case BT_DERIVED:
 116       type = gfc_typenode_for_spec (&e->ts);
 117       return int_size_in_bytes (type);
 118     default:
 119       gfc_internal_error ("Invalid expression in gfc_target_expr_size.");
 120       return 0;
 121     }
 122 }
 123
 124
 125 /* The encode_* functions export a value into a buffer, and
 126    return the number of bytes of the buffer that have been
 127    used.  */
 128
 129 static int
 130 encode_array (gfc_expr *expr, unsigned char *buffer, size_t buffer_size)
 131 {
 132   mpz_t array_size;
 133   int i;
 134   int ptr = 0;
 135
 136   gfc_array_size (expr, &array_size);
 137   for (i = 0; i < (int)mpz_get_ui (array_size); i++)
 138     {
 139       ptr += gfc_target_encode_expr (gfc_get_array_element (expr, i),
 140                                      &buffer[ptr], buffer_size - ptr);
 141     }
 142
 143   mpz_clear (array_size);
 144   return ptr;
 145 }
 146
 147
 148 static int
 149 encode_integer (int kind, mpz_t integer, unsigned char *buffer,
 150                 size_t buffer_size)
 151 {
 152   return native_encode_expr (gfc_conv_mpz_to_tree (integer, kind),
 153                              buffer, buffer_size);
 154 }
 155
 156
 157 static int
 158 encode_float (int kind, mpfr_t real, unsigned char *buffer, size_t buffer_size)
 159 {
 160   return native_encode_expr (gfc_conv_mpfr_to_tree (real, kind), buffer,
 161                              buffer_size);
 162 }
 163
 164
 165 static int
 166 encode_complex (int kind, mpfr_t real, mpfr_t imaginary, unsigned char *buffer,
 167                 size_t buffer_size)
 168 {
 169   int size;
 170   size = encode_float (kind, real, &buffer[0], buffer_size);
 171   size += encode_float (kind, imaginary, &buffer[size], buffer_size - size);
 172   return size;
 173 }
 174
 175
 176 static int
 177 encode_logical (int kind, int logical, unsigned char *buffer, size_t buffer_size)
 178 {
 179   return native_encode_expr (build_int_cst (gfc_get_logical_type (kind),
 180                                             logical),
 181                              buffer, buffer_size);
 182 }
 183
 184
 185 static int
 186 encode_character (int kind, int length, gfc_char_t *string,
 187                   unsigned char *buffer, size_t buffer_size)
 188 {
 189   char *s;
 190
 191   gcc_assert (buffer_size >= size_character (length, kind));
 192   /* FIXME -- when we support wide character types, we'll need to go
 193      via integers for them.  For now, we keep the simple memcpy().  */
 194   gcc_assert (kind == gfc_default_character_kind);
 195
 196   s = gfc_widechar_to_char (string, length);
 197   memcpy (buffer, s, length);
 198   gfc_free (s);
 199
 200   return length;
 201 }
 202
 203
 204 static int
 205 encode_derived (gfc_expr *source, unsigned char *buffer, size_t buffer_size)
 206 {
 207   gfc_constructor *ctr;
 208   gfc_component *cmp;
 209   int ptr;
 210   tree type;
 211
 212   type = gfc_typenode_for_spec (&source->ts);
 213
 214   ctr = source->value.constructor;
 215   cmp = source->ts.derived->components;
 216   for (;ctr; ctr = ctr->next, cmp = cmp->next)
 217     {
 218       gcc_assert (cmp);
 219       if (!ctr->expr)
 220         continue;
 221       ptr = TREE_INT_CST_LOW(DECL_FIELD_OFFSET(cmp->backend_decl))
 222             + TREE_INT_CST_LOW(DECL_FIELD_BIT_OFFSET(cmp->backend_decl))/8;
 223       gfc_target_encode_expr (ctr->expr, &buffer[ptr],
 224                               buffer_size - ptr);
 225     }
 226
 227   return int_size_in_bytes (type);
 228 }
 229
 230
 231 /* Write a constant expression in binary form to a buffer.  */
 232 int
 233 gfc_target_encode_expr (gfc_expr *source, unsigned char *buffer,
 234                         size_t buffer_size)
 235 {
 236   if (source == NULL)
 237     return 0;
 238
 239   if (source->expr_type == EXPR_ARRAY)
 240     return encode_array (source, buffer, buffer_size);
 241
 242   gcc_assert (source->expr_type == EXPR_CONSTANT
 243               || source->expr_type == EXPR_STRUCTURE
 244               || source->expr_type == EXPR_SUBSTRING);
 245
 246   /* If we already have a target-memory representation, we use that rather
 247      than recreating one.  */
 248   if (source->representation.string)
 249     {
 250       memcpy (buffer, source->representation.string,
 251               source->representation.length);
 252       return source->representation.length;
 253     }
 254
 255   switch (source->ts.type)
 256     {
 257     case BT_INTEGER:
 258       return encode_integer (source->ts.kind, source->value.integer, buffer,
 259                              buffer_size);
 260     case BT_REAL:
 261       return encode_float (source->ts.kind, source->value.real, buffer,
 262                            buffer_size);
 263     case BT_COMPLEX:
 264       return encode_complex (source->ts.kind, source->value.complex.r,
 265                              source->value.complex.i, buffer, buffer_size);
 266     case BT_LOGICAL:
 267       return encode_logical (source->ts.kind, source->value.logical, buffer,
 268                              buffer_size);
 269     case BT_CHARACTER:
 270       if (source->expr_type == EXPR_CONSTANT || source->ref == NULL)
 271         return encode_character (source->ts.kind,
 272                                  source->value.character.length,
 273                                  source->value.character.string, buffer,
 274                                  buffer_size);
 275       else
 276         {
 277           int start, end;
 278
 279           gcc_assert (source->expr_type == EXPR_SUBSTRING);
 280           gfc_extract_int (source->ref->u.ss.start, &start);
 281           gfc_extract_int (source->ref->u.ss.end, &end);
 282           return encode_character (source->ts.kind,
 283                                    MAX(end - start + 1, 0),
 284                                    &source->value.character.string[start-1],
 285                                    buffer, buffer_size);
 286         }
 287
 288     case BT_DERIVED:
 289       return encode_derived (source, buffer, buffer_size);
 290     default:
 291       gfc_internal_error ("Invalid expression in gfc_target_encode_expr.");
 292       return 0;
 293     }
 294 }
 295
 296
 297 static int
 298 interpret_array (unsigned char *buffer, size_t buffer_size, gfc_expr *result)
 299 {
 300   int array_size = 1;
 301   int i;
 302   int ptr = 0;
 303   gfc_constructor *head = NULL, *tail = NULL;
 304
 305   /* Calculate array size from its shape and rank.  */
 306   gcc_assert (result->rank > 0 && result->shape);
 307
 308   for (i = 0; i < result->rank; i++)
 309     array_size *= (int)mpz_get_ui (result->shape[i]);
 310
 311   /* Iterate over array elements, producing constructors.  */
 312   for (i = 0; i < array_size; i++)
 313     {
 314       if (head == NULL)
 315         head = tail = gfc_get_constructor ();
 316       else
 317         {
 318           tail->next = gfc_get_constructor ();
 319           tail = tail->next;
 320         }
 321
 322       tail->where = result->where;
 323       tail->expr = gfc_constant_result (result->ts.type,
 324                                           result->ts.kind, &result->where);
 325       tail->expr->ts = result->ts;
 326
 327       if (tail->expr->ts.type == BT_CHARACTER)
 328         tail->expr->value.character.length = result->value.character.length;
 329
 330       ptr += gfc_target_interpret_expr (&buffer[ptr], buffer_size - ptr,
 331                                         tail->expr);
 332     }
 333   result->value.constructor = head;
 334
 335   return ptr;
 336 }
 337
 338
 339 int
 340 gfc_interpret_integer (int kind, unsigned char *buffer, size_t buffer_size,
 341                    mpz_t integer)
 342 {
 343   mpz_init (integer);
 344   gfc_conv_tree_to_mpz (integer,
 345                         native_interpret_expr (gfc_get_int_type (kind),
 346                                                buffer, buffer_size));
 347   return size_integer (kind);
 348 }
 349
 350
 351 int
 352 gfc_interpret_float (int kind, unsigned char *buffer, size_t buffer_size,
 353                  mpfr_t real)
 354 {
 355   mpfr_init (real);
 356   gfc_conv_tree_to_mpfr (real,
 357                          native_interpret_expr (gfc_get_real_type (kind),
 358                                                 buffer, buffer_size));
 359
 360   return size_float (kind);
 361 }
 362
 363
 364 int
 365 gfc_interpret_complex (int kind, unsigned char *buffer, size_t buffer_size,
 366                    mpfr_t real, mpfr_t imaginary)
 367 {
 368   int size;
 369   size = gfc_interpret_float (kind, &buffer[0], buffer_size, real);
 370   size += gfc_interpret_float (kind, &buffer[size], buffer_size - size,
 371                                imaginary);
 372   return size;
 373 }
 374
 375
 376 int
 377 gfc_interpret_logical (int kind, unsigned char *buffer, size_t buffer_size,
 378                    int *logical)
 379 {
 380   tree t = native_interpret_expr (gfc_get_logical_type (kind), buffer,
 381                                   buffer_size);
 382   *logical = double_int_zero_p (tree_to_double_int (t))
 383              ? 0 : 1;
 384   return size_logical (kind);
 385 }
 386
 387
 388 int
 389 gfc_interpret_character (unsigned char *buffer, size_t buffer_size,
 390                          gfc_expr *result)
 391 {
 392   int i;
 393
 394   if (result->ts.cl && result->ts.cl->length)
 395     result->value.character.length =
 396       (int) mpz_get_ui (result->ts.cl->length->value.integer);
 397
 398   gcc_assert (buffer_size >= size_character (result->value.character.length,
 399                                              result->ts.kind));
 400   result->value.character.string =
 401     gfc_get_wide_string (result->value.character.length + 1);
 402
 403   gcc_assert (result->ts.kind == gfc_default_character_kind);
 404   for (i = 0; i < result->value.character.length; i++)
 405     result->value.character.string[i] = (gfc_char_t) buffer[i];
 406   result->value.character.string[result->value.character.length] = '\0';
 407
 408   return result->value.character.length;
 409 }
 410
 411
 412 int
 413 gfc_interpret_derived (unsigned char *buffer, size_t buffer_size, gfc_expr *result)
 414 {
 415   gfc_component *cmp;
 416   gfc_constructor *head = NULL, *tail = NULL;
 417   int ptr;
 418   tree type;
 419
 420   /* The attributes of the derived type need to be bolted to the floor.  */
 421   result->expr_type = EXPR_STRUCTURE;
 422
 423   type = gfc_typenode_for_spec (&result->ts);
 424   cmp = result->ts.derived->components;
 425
 426   /* Run through the derived type components.  */
 427   for (;cmp; cmp = cmp->next)
 428     {
 429       if (head == NULL)
 430         head = tail = gfc_get_constructor ();
 431       else
 432         {
 433           tail->next = gfc_get_constructor ();
 434           tail = tail->next;
 435         }
 436
 437       /* The constructor points to the component.  */
 438       tail->n.component = cmp;
 439
 440       tail->expr = gfc_constant_result (cmp->ts.type, cmp->ts.kind,
 441                                         &result->where);
 442       tail->expr->ts = cmp->ts;
 443
 444       /* Copy shape, if needed.  */
 445       if (cmp->as && cmp->as->rank)
 446         {
 447           int n;
 448
 449           tail->expr->expr_type = EXPR_ARRAY;
 450           tail->expr->rank = cmp->as->rank;
 451
 452           tail->expr->shape = gfc_get_shape (tail->expr->rank);
 453           for (n = 0; n < tail->expr->rank; n++)
 454              {
 455                mpz_init_set_ui (tail->expr->shape[n], 1);
 456                mpz_add (tail->expr->shape[n], tail->expr->shape[n],
 457                         cmp->as->upper[n]->value.integer);
 458                mpz_sub (tail->expr->shape[n], tail->expr->shape[n],
 459                         cmp->as->lower[n]->value.integer);
 460              }
 461         }
 462
 463       ptr = TREE_INT_CST_LOW (DECL_FIELD_OFFSET (cmp->backend_decl));
 464       gfc_target_interpret_expr (&buffer[ptr], buffer_size - ptr,
 465                                  tail->expr);
 466
 467       result->value.constructor = head;
 468     }
 469
 470   return int_size_in_bytes (type);
 471 }
 472
 473
 474 /* Read a binary buffer to a constant expression.  */
 475 int
 476 gfc_target_interpret_expr (unsigned char *buffer, size_t buffer_size,
 477                            gfc_expr *result)
 478 {
 479   if (result->expr_type == EXPR_ARRAY)
 480     return interpret_array (buffer, buffer_size, result);
 481
 482   switch (result->ts.type)
 483     {
 484     case BT_INTEGER:
 485       result->representation.length =
 486         gfc_interpret_integer (result->ts.kind, buffer, buffer_size,
 487                                result->value.integer);
 488       break;
 489
 490     case BT_REAL:
 491       result->representation.length =
 492         gfc_interpret_float (result->ts.kind, buffer, buffer_size,
 493                              result->value.real);
 494       break;
 495
 496     case BT_COMPLEX:
 497       result->representation.length =
 498         gfc_interpret_complex (result->ts.kind, buffer, buffer_size,
 499                                result->value.complex.r,
 500                                result->value.complex.i);
 501       break;
 502
 503     case BT_LOGICAL:
 504       result->representation.length =
 505         gfc_interpret_logical (result->ts.kind, buffer, buffer_size,
 506                                &result->value.logical);
 507       break;
 508
 509     case BT_CHARACTER:
 510       result->representation.length =
 511         gfc_interpret_character (buffer, buffer_size, result);
 512       break;
 513
 514     case BT_DERIVED:
 515       result->representation.length =
 516         gfc_interpret_derived (buffer, buffer_size, result);
 517       break;
 518
 519     default:
 520       gfc_internal_error ("Invalid expression in gfc_target_interpret_expr.");
 521       break;
 522     }
 523
 524   if (result->ts.type == BT_CHARACTER)
 525     result->representation.string
 526       = gfc_widechar_to_char (result->value.character.string,
 527                               result->value.character.length);
 528   else
 529     {
 530       result->representation.string =
 531         gfc_getmem (result->representation.length + 1);
 532       memcpy (result->representation.string, buffer,
 533               result->representation.length);
 534       result->representation.string[result->representation.length] = '\0';
 535     }
 536
 537   return result->representation.length;
 538 }
 539
 540
 541 /* --------------------------------------------------------------- */
 542 /* Two functions used by trans-common.c to write overlapping
 543    equivalence initializers to a buffer.  This is added to the union
 544    and the original initializers freed.  */
 545
 546
 547 /* Writes the values of a constant expression to a char buffer. If another
 548    unequal initializer has already been written to the buffer, this is an
 549    error.  */
 550
 551 static size_t
 552 expr_to_char (gfc_expr *e, unsigned char *data, unsigned char *chk, size_t len)
 553 {
 554   int i;
 555   int ptr;
 556   gfc_constructor *ctr;
 557   gfc_component *cmp;
 558   unsigned char *buffer;
 559
 560   if (e == NULL)
 561     return 0;
 562
 563   /* Take a derived type, one component at a time, using the offsets from the backend
 564      declaration.  */
 565   if (e->ts.type == BT_DERIVED)
 566     {
 567       ctr = e->value.constructor;
 568       cmp = e->ts.derived->components;
 569       for (;ctr; ctr = ctr->next, cmp = cmp->next)
 570         {
 571           gcc_assert (cmp && cmp->backend_decl);
 572           if (!ctr->expr)
 573             continue;
 574             ptr = TREE_INT_CST_LOW(DECL_FIELD_OFFSET(cmp->backend_decl))
 575                         + TREE_INT_CST_LOW(DECL_FIELD_BIT_OFFSET(cmp->backend_decl))/8;
 576           expr_to_char (ctr->expr, &data[ptr], &chk[ptr], len);
 577         }
 578       return len;
 579     }
 580
 581   /* Otherwise, use the target-memory machinery to write a bitwise image, appropriate
 582      to the target, in a buffer and check off the initialized part of the buffer.  */
 583   len = gfc_target_expr_size (e);
 584   buffer = (unsigned char*)alloca (len);
 585   len = gfc_target_encode_expr (e, buffer, len);
 586
 587     for (i = 0; i < (int)len; i++)
 588     {
 589       if (chk[i] && (buffer[i] != data[i]))
 590         {
 591           gfc_error ("Overlapping unequal initializers in EQUIVALENCE "
 592                      "at %L", &e->where);
 593           return 0;
 594         }
 595       chk[i] = 0xFF;
 596     }
 597
 598   memcpy (data, buffer, len);
 599   return len;
 600 }
 601
 602
 603 /* Writes the values from the equivalence initializers to a char* array
 604    that will be written to the constructor to make the initializer for
 605    the union declaration.  */
 606
 607 size_t
 608 gfc_merge_initializers (gfc_typespec ts, gfc_expr *e, unsigned char *data,
 609                         unsigned char *chk, size_t length)
 610 {
 611   size_t len = 0;
 612   gfc_constructor * c;
 613
 614   switch (e->expr_type)
 615     {
 616     case EXPR_CONSTANT:
 617     case EXPR_STRUCTURE:
 618       len = expr_to_char (e, &data[0], &chk[0], length);
 619
 620       break;
 621
 622     case EXPR_ARRAY:
 623       for (c = e->value.constructor; c; c = c->next)
 624         {
 625           size_t elt_size = gfc_target_expr_size (c->expr);
 626
 627           if (c->n.offset)
 628             len = elt_size * (size_t)mpz_get_si (c->n.offset);
 629
 630           len = len + gfc_merge_initializers (ts, c->expr, &data[len],
 631                                               &chk[len], length - len);
 632         }
 633       break;
 634
 635     default:
 636       return 0;
 637     }
 638
 639   return len;
 640 }
 641
 642
 643 /* Transfer the bitpattern of a (integer) BOZ to real or complex variables.
 644    When successful, no BOZ or nothing to do, true is returned.  */
 645
 646 bool
 647 gfc_convert_boz (gfc_expr *expr, gfc_typespec *ts)
 648 {
 649   size_t buffer_size, boz_bit_size, ts_bit_size;
 650   int index;
 651   unsigned char *buffer;
 652
 653   if (!expr->is_boz)
 654     return true;
 655
 656   gcc_assert (expr->expr_type == EXPR_CONSTANT
 657               && expr->ts.type == BT_INTEGER);
 658
 659   /* Don't convert BOZ to logical, character, derived etc.  */
 660   if (ts->type == BT_REAL)
 661     {
 662       buffer_size = size_float (ts->kind);
 663       ts_bit_size = buffer_size * 8;
 664     }
 665   else if (ts->type == BT_COMPLEX)
 666     {
 667       buffer_size = size_complex (ts->kind);
 668       ts_bit_size = buffer_size * 8 / 2;
 669     }
 670   else
 671     return true;
 672
 673   /* Convert BOZ to the smallest possible integer kind.  */
 674   boz_bit_size = mpz_sizeinbase (expr->value.integer, 2);
 675
 676   if (boz_bit_size > ts_bit_size)
 677     {
 678       gfc_error_now ("BOZ constant at %L is too large (%ld vs %ld bits)",
 679                      &expr->where, (long) boz_bit_size, (long) ts_bit_size);
 680       return false;
 681     }
 682
 683   for (index = 0; gfc_integer_kinds[index].kind != 0; ++index)
 684     {
 685         if ((unsigned) gfc_integer_kinds[index].bit_size >= ts_bit_size)
 686           break;
 687     }
 688
 689   expr->ts.kind = gfc_integer_kinds[index].kind;
 690   buffer_size = MAX (buffer_size, size_integer (expr->ts.kind));
 691
 692   buffer = (unsigned char*)alloca (buffer_size);
 693   encode_integer (expr->ts.kind, expr->value.integer, buffer, buffer_size);
 694   mpz_clear (expr->value.integer);
 695
 696   if (ts->type == BT_REAL)
 697     {
 698       mpfr_init (expr->value.real);
 699       gfc_interpret_float (ts->kind, buffer, buffer_size, expr->value.real);
 700     }
 701   else
 702     {
 703       mpfr_init (expr->value.complex.r);
 704       mpfr_init (expr->value.complex.i);
 705       gfc_interpret_complex (ts->kind, buffer, buffer_size,
 706                              expr->value.complex.r, expr->value.complex.i);
 707     }
 708   expr->is_boz = 0;
 709   expr->ts.type = ts->type;
 710   expr->ts.kind = ts->kind;
 711
 712   return true;
 713 }