gcc/fortran/trans-const.c

   1 /* Translation of constants
   2    Copyright (C) 2002-2018 Free Software Foundation, Inc.
   3    Contributed by Paul Brook
   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 3, 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 COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 /* trans-const.c -- convert constant values */
  22
  23 #include "config.h"
  24 #include "system.h"
  25 #include "coretypes.h"
  26 #include "tree.h"
  27 #include "gfortran.h"
  28 #include "trans.h"
  29 #include "fold-const.h"
  30 #include "stor-layout.h"
  31 #include "realmpfr.h"
  32 #include "trans-const.h"
  33 #include "trans-types.h"
  34 #include "target-memory.h"
  35
  36 tree gfc_rank_cst[GFC_MAX_DIMENSIONS + 1];
  37
  38 /* Build a constant with given type from an int_cst.  */
  39
  40 tree
  41 gfc_build_const (tree type, tree intval)
  42 {
  43   tree val;
  44   tree zero;
  45
  46   switch (TREE_CODE (type))
  47     {
  48     case INTEGER_TYPE:
  49       val = convert (type, intval);
  50       break;
  51
  52     case REAL_TYPE:
  53       val = build_real_from_int_cst (type, intval);
  54       break;
  55
  56     case COMPLEX_TYPE:
  57       val = build_real_from_int_cst (TREE_TYPE (type), intval);
  58       zero = build_real_from_int_cst (TREE_TYPE (type), integer_zero_node);
  59       val = build_complex (type, val, zero);
  60       break;
  61
  62     default:
  63       gcc_unreachable ();
  64     }
  65   return val;
  66 }
  67
  68 /* Build a string constant with C char type.  */
  69
  70 tree
  71 gfc_build_string_const (size_t length, const char *s)
  72 {
  73   tree str;
  74   tree len;
  75
  76   str = build_string (length, s);
  77   len = size_int (length);
  78   TREE_TYPE (str) =
  79     build_array_type (gfc_character1_type_node,
  80                       build_range_type (gfc_charlen_type_node,
  81                                         size_one_node, len));
  82   TYPE_STRING_FLAG (TREE_TYPE (str)) = 1;
  83   return str;
  84 }
  85
  86
  87 /* Build a string constant with a type given by its kind; take care of
  88    non-default character kinds.  */
  89
  90 tree
  91 gfc_build_wide_string_const (int kind, size_t length, const gfc_char_t *string)
  92 {
  93   int i;
  94   tree str, len;
  95   size_t size;
  96   char *s;
  97
  98   i = gfc_validate_kind (BT_CHARACTER, kind, false);
  99   size = length * gfc_character_kinds[i].bit_size / 8;
 100
 101   s = XCNEWVAR (char, size);
 102   gfc_encode_character (kind, length, string, (unsigned char *) s, size);
 103
 104   str = build_string (size, s);
 105   free (s);
 106
 107   len = size_int (length);
 108   TREE_TYPE (str) =
 109     build_array_type (gfc_get_char_type (kind),
 110                       build_range_type (gfc_charlen_type_node,
 111                                         size_one_node, len));
 112   TYPE_STRING_FLAG (TREE_TYPE (str)) = 1;
 113   return str;
 114 }
 115
 116
 117 /* Build a Fortran character constant from a zero-terminated string.
 118    There a two version of this function, one that translates the string
 119    and one that doesn't.  */
 120 tree
 121 gfc_build_cstring_const (const char *string)
 122 {
 123   return gfc_build_string_const (strlen (string) + 1, string);
 124 }
 125
 126 tree
 127 gfc_build_localized_cstring_const (const char *msgid)
 128 {
 129   const char *localized = _(msgid);
 130   return gfc_build_string_const (strlen (localized) + 1, localized);
 131 }
 132
 133
 134 /* Return a string constant with the given length.  Used for static
 135    initializers.  The constant will be padded or truncated to match
 136    length.  */
 137
 138 tree
 139 gfc_conv_string_init (tree length, gfc_expr * expr)
 140 {
 141   gfc_char_t *s;
 142   HOST_WIDE_INT len;
 143   gfc_charlen_t slen;
 144   tree str;
 145   bool free_s = false;
 146
 147   gcc_assert (expr->expr_type == EXPR_CONSTANT);
 148   gcc_assert (expr->ts.type == BT_CHARACTER);
 149   gcc_assert (tree_fits_uhwi_p (length));
 150
 151   len = TREE_INT_CST_LOW (length);
 152   slen = expr->value.character.length;
 153
 154   if (len > slen)
 155     {
 156       s = gfc_get_wide_string (len);
 157       memcpy (s, expr->value.character.string, slen * sizeof (gfc_char_t));
 158       gfc_wide_memset (&s[slen], ' ', len - slen);
 159       free_s = true;
 160     }
 161   else
 162     s = expr->value.character.string;
 163
 164   str = gfc_build_wide_string_const (expr->ts.kind, len, s);
 165
 166   if (free_s)
 167     free (s);
 168
 169   return str;
 170 }
 171
 172
 173 /* Create a tree node for the string length if it is constant.  */
 174
 175 void
 176 gfc_conv_const_charlen (gfc_charlen * cl)
 177 {
 178   if (!cl || cl->backend_decl)
 179     return;
 180
 181   if (cl->length && cl->length->expr_type == EXPR_CONSTANT)
 182     {
 183       cl->backend_decl = gfc_conv_mpz_to_tree (cl->length->value.integer,
 184                                                cl->length->ts.kind);
 185       cl->backend_decl = fold_convert (gfc_charlen_type_node,
 186                                         cl->backend_decl);
 187     }
 188 }
 189
 190 void
 191 gfc_init_constants (void)
 192 {
 193   int n;
 194
 195   for (n = 0; n <= GFC_MAX_DIMENSIONS; n++)
 196     gfc_rank_cst[n] = build_int_cst (gfc_array_index_type, n);
 197 }
 198
 199 /* Converts a GMP integer into a backend tree node.  */
 200
 201 tree
 202 gfc_conv_mpz_to_tree (mpz_t i, int kind)
 203 {
 204   wide_int val = wi::from_mpz (gfc_get_int_type (kind), i, true);
 205   return wide_int_to_tree (gfc_get_int_type (kind), val);
 206 }
 207
 208
 209 /* Convert a GMP integer into a tree node of type given by the type
 210    argument.  */
 211
 212 tree
 213 gfc_conv_mpz_to_tree_type (mpz_t i, const tree type)
 214 {
 215   const wide_int val = wi::from_mpz (type, i, true);
 216   return wide_int_to_tree (type, val);
 217 }
 218
 219
 220 /* Converts a backend tree into a GMP integer.  */
 221
 222 void
 223 gfc_conv_tree_to_mpz (mpz_t i, tree source)
 224 {
 225   wi::to_mpz (wi::to_wide (source), i, TYPE_SIGN (TREE_TYPE (source)));
 226 }
 227
 228 /* Converts a real constant into backend form.  */
 229
 230 tree
 231 gfc_conv_mpfr_to_tree (mpfr_t f, int kind, int is_snan)
 232 {
 233   tree type;
 234   int n;
 235   REAL_VALUE_TYPE real;
 236
 237   n = gfc_validate_kind (BT_REAL, kind, false);
 238   gcc_assert (gfc_real_kinds[n].radix == 2);
 239
 240   type = gfc_get_real_type (kind);
 241   if (mpfr_nan_p (f) && is_snan)
 242      real_from_string (&real, "SNaN");
 243   else
 244     real_from_mpfr (&real, f, type, GFC_RND_MODE);
 245
 246   return build_real (type, real);
 247 }
 248
 249 /* Returns a real constant that is +Infinity if the target
 250    supports infinities for this floating-point mode, and
 251    +HUGE_VAL otherwise (the largest representable number).  */
 252
 253 tree
 254 gfc_build_inf_or_huge (tree type, int kind)
 255 {
 256   if (HONOR_INFINITIES (TYPE_MODE (type)))
 257     {
 258       REAL_VALUE_TYPE real;
 259       real_inf (&real);
 260       return build_real (type, real);
 261     }
 262   else
 263     {
 264       int k = gfc_validate_kind (BT_REAL, kind, false);
 265       return gfc_conv_mpfr_to_tree (gfc_real_kinds[k].huge, kind, 0);
 266     }
 267 }
 268
 269 /* Returns a floating-point NaN of a given type.  */
 270
 271 tree
 272 gfc_build_nan (tree type, const char *str)
 273 {
 274   REAL_VALUE_TYPE real;
 275   real_nan (&real, str, 1, TYPE_MODE (type));
 276   return build_real (type, real);
 277 }
 278
 279 /* Converts a backend tree into a real constant.  */
 280
 281 void
 282 gfc_conv_tree_to_mpfr (mpfr_ptr f, tree source)
 283 {
 284   mpfr_from_real (f, TREE_REAL_CST_PTR (source), GFC_RND_MODE);
 285 }
 286
 287 /* Translate any literal constant to a tree.  Constants never have
 288    pre or post chains.  Character literal constants are special
 289    special because they have a value and a length, so they cannot be
 290    returned as a single tree.  It is up to the caller to set the
 291    length somewhere if necessary.
 292
 293    Returns the translated constant, or aborts if it gets a type it
 294    can't handle.  */
 295
 296 tree
 297 gfc_conv_constant_to_tree (gfc_expr * expr)
 298 {
 299   tree res;
 300
 301   gcc_assert (expr->expr_type == EXPR_CONSTANT);
 302
 303   /* If it is has a prescribed memory representation, we build a string
 304      constant and VIEW_CONVERT to its type.  */
 305
 306   switch (expr->ts.type)
 307     {
 308     case BT_INTEGER:
 309       if (expr->representation.string)
 310         return fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 311                          gfc_get_int_type (expr->ts.kind),
 312                          gfc_build_string_const (expr->representation.length,
 313                                                  expr->representation.string));
 314       else
 315         return gfc_conv_mpz_to_tree (expr->value.integer, expr->ts.kind);
 316
 317     case BT_REAL:
 318       if (expr->representation.string)
 319         return fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 320                          gfc_get_real_type (expr->ts.kind),
 321                          gfc_build_string_const (expr->representation.length,
 322                                                  expr->representation.string));
 323       else
 324         return gfc_conv_mpfr_to_tree (expr->value.real, expr->ts.kind, expr->is_snan);
 325
 326     case BT_LOGICAL:
 327       if (expr->representation.string)
 328         {
 329           tree tmp = fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 330                         gfc_get_int_type (expr->ts.kind),
 331                         gfc_build_string_const (expr->representation.length,
 332                                                 expr->representation.string));
 333           if (!integer_zerop (tmp) && !integer_onep (tmp))
 334             gfc_warning (0, "Assigning value other than 0 or 1 to LOGICAL"
 335                          " has undefined result at %L", &expr->where);
 336           return fold_convert (gfc_get_logical_type (expr->ts.kind), tmp);
 337         }
 338       else
 339         return build_int_cst (gfc_get_logical_type (expr->ts.kind),
 340                               expr->value.logical);
 341
 342     case BT_COMPLEX:
 343       if (expr->representation.string)
 344         return fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 345                          gfc_get_complex_type (expr->ts.kind),
 346                          gfc_build_string_const (expr->representation.length,
 347                                                  expr->representation.string));
 348       else
 349         {
 350           tree real = gfc_conv_mpfr_to_tree (mpc_realref (expr->value.complex),
 351                                           expr->ts.kind, expr->is_snan);
 352           tree imag = gfc_conv_mpfr_to_tree (mpc_imagref (expr->value.complex),
 353                                           expr->ts.kind, expr->is_snan);
 354
 355           return build_complex (gfc_typenode_for_spec (&expr->ts),
 356                                 real, imag);
 357         }
 358
 359     case BT_CHARACTER:
 360       res = gfc_build_wide_string_const (expr->ts.kind,
 361                                          expr->value.character.length,
 362                                          expr->value.character.string);
 363       return res;
 364
 365     case BT_HOLLERITH:
 366       return gfc_build_string_const (expr->representation.length,
 367                                      expr->representation.string);
 368
 369     default:
 370       gcc_unreachable ();
 371     }
 372 }
 373
 374
 375 /* Like gfc_conv_constant_to_tree, but for a simplified expression.
 376    We can handle character literal constants here as well.  */
 377
 378 void
 379 gfc_conv_constant (gfc_se * se, gfc_expr * expr)
 380 {
 381   gfc_ss *ss;
 382
 383   /* We may be receiving an expression for C_NULL_PTR or C_NULL_FUNPTR.  If
 384      so, the expr_type will not yet be an EXPR_CONSTANT.  We need to make
 385      it so here.  */
 386   if (expr->ts.type == BT_DERIVED && expr->ts.u.derived
 387       && expr->ts.u.derived->attr.is_iso_c)
 388     {
 389       if (expr->symtree->n.sym->intmod_sym_id == ISOCBINDING_NULL_PTR
 390           || expr->symtree->n.sym->intmod_sym_id == ISOCBINDING_NULL_FUNPTR)
 391         {
 392           /* Create a new EXPR_CONSTANT expression for our local uses.  */
 393           expr = gfc_get_int_expr (gfc_default_integer_kind, NULL, 0);
 394         }
 395     }
 396
 397   if (expr->expr_type != EXPR_CONSTANT)
 398     {
 399       gfc_expr *e = gfc_get_int_expr (gfc_default_integer_kind, NULL, 0);
 400       gfc_error ("non-constant initialization expression at %L", &expr->where);
 401       se->expr = gfc_conv_constant_to_tree (e);
 402       return;
 403     }
 404
 405   ss = se->ss;
 406   if (ss != NULL)
 407     {
 408       gfc_ss_info *ss_info;
 409
 410       ss_info = ss->info;
 411       gcc_assert (ss != gfc_ss_terminator);
 412       gcc_assert (ss_info->type == GFC_SS_SCALAR);
 413       gcc_assert (ss_info->expr == expr);
 414
 415       se->expr = ss_info->data.scalar.value;
 416       se->string_length = ss_info->string_length;
 417       gfc_advance_se_ss_chain (se);
 418       return;
 419     }
 420
 421   /* Translate the constant and put it in the simplifier structure.  */
 422   se->expr = gfc_conv_constant_to_tree (expr);
 423
 424   /* If this is a CHARACTER string, set its length in the simplifier
 425      structure, too.  */
 426   if (expr->ts.type == BT_CHARACTER)
 427     se->string_length = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (se->expr)));
 428 }