gcc/fortran/trans-const.c

   1 /* Translation of constants
   2    Copyright (C) 2002-2015 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 "gfortran.h"
  27 #include "hash-set.h"
  28 #include "machmode.h"
  29 #include "vec.h"
  30 #include "double-int.h"
  31 #include "input.h"
  32 #include "alias.h"
  33 #include "symtab.h"
  34 #include "options.h"
  35 #include "real.h"
  36 #include "wide-int.h"
  37 #include "inchash.h"
  38 #include "tree.h"
  39 #include "fold-const.h"
  40 #include "stor-layout.h"
  41 #include "realmpfr.h"
  42 #include "diagnostic-core.h"    /* For fatal_error.  */
  43 #include "double-int.h"
  44 #include "trans.h"
  45 #include "trans-const.h"
  46 #include "trans-types.h"
  47 #include "target-memory.h"
  48
  49 tree gfc_rank_cst[GFC_MAX_DIMENSIONS + 1];
  50
  51 /* Build a constant with given type from an int_cst.  */
  52
  53 tree
  54 gfc_build_const (tree type, tree intval)
  55 {
  56   tree val;
  57   tree zero;
  58
  59   switch (TREE_CODE (type))
  60     {
  61     case INTEGER_TYPE:
  62       val = convert (type, intval);
  63       break;
  64
  65     case REAL_TYPE:
  66       val = build_real_from_int_cst (type, intval);
  67       break;
  68
  69     case COMPLEX_TYPE:
  70       val = build_real_from_int_cst (TREE_TYPE (type), intval);
  71       zero = build_real_from_int_cst (TREE_TYPE (type), integer_zero_node);
  72       val = build_complex (type, val, zero);
  73       break;
  74
  75     default:
  76       gcc_unreachable ();
  77     }
  78   return val;
  79 }
  80
  81 /* Build a string constant with C char type.  */
  82
  83 tree
  84 gfc_build_string_const (int length, const char *s)
  85 {
  86   tree str;
  87   tree len;
  88
  89   str = build_string (length, s);
  90   len = size_int (length);
  91   TREE_TYPE (str) =
  92     build_array_type (gfc_character1_type_node,
  93                       build_range_type (gfc_charlen_type_node,
  94                                         size_one_node, len));
  95   TYPE_STRING_FLAG (TREE_TYPE (str)) = 1;
  96   return str;
  97 }
  98
  99
 100 /* Build a string constant with a type given by its kind; take care of
 101    non-default character kinds.  */
 102
 103 tree
 104 gfc_build_wide_string_const (int kind, int length, const gfc_char_t *string)
 105 {
 106   int i;
 107   tree str, len;
 108   size_t size;
 109   char *s;
 110
 111   i = gfc_validate_kind (BT_CHARACTER, kind, false);
 112   size = length * gfc_character_kinds[i].bit_size / 8;
 113
 114   s = XCNEWVAR (char, size);
 115   gfc_encode_character (kind, length, string, (unsigned char *) s, size);
 116
 117   str = build_string (size, s);
 118   free (s);
 119
 120   len = size_int (length);
 121   TREE_TYPE (str) =
 122     build_array_type (gfc_get_char_type (kind),
 123                       build_range_type (gfc_charlen_type_node,
 124                                         size_one_node, len));
 125   TYPE_STRING_FLAG (TREE_TYPE (str)) = 1;
 126   return str;
 127 }
 128
 129
 130 /* Build a Fortran character constant from a zero-terminated string.
 131    There a two version of this function, one that translates the string
 132    and one that doesn't.  */
 133 tree
 134 gfc_build_cstring_const (const char *string)
 135 {
 136   return gfc_build_string_const (strlen (string) + 1, string);
 137 }
 138
 139 tree
 140 gfc_build_localized_cstring_const (const char *msgid)
 141 {
 142   const char *localized = _(msgid);
 143   return gfc_build_string_const (strlen (localized) + 1, localized);
 144 }
 145
 146
 147 /* Return a string constant with the given length.  Used for static
 148    initializers.  The constant will be padded or truncated to match
 149    length.  */
 150
 151 tree
 152 gfc_conv_string_init (tree length, gfc_expr * expr)
 153 {
 154   gfc_char_t *s;
 155   HOST_WIDE_INT len;
 156   int slen;
 157   tree str;
 158   bool free_s = false;
 159
 160   gcc_assert (expr->expr_type == EXPR_CONSTANT);
 161   gcc_assert (expr->ts.type == BT_CHARACTER);
 162   gcc_assert (tree_fits_uhwi_p (length));
 163
 164   len = TREE_INT_CST_LOW (length);
 165   slen = expr->value.character.length;
 166
 167   if (len > slen)
 168     {
 169       s = gfc_get_wide_string (len);
 170       memcpy (s, expr->value.character.string, slen * sizeof (gfc_char_t));
 171       gfc_wide_memset (&s[slen], ' ', len - slen);
 172       free_s = true;
 173     }
 174   else
 175     s = expr->value.character.string;
 176
 177   str = gfc_build_wide_string_const (expr->ts.kind, len, s);
 178
 179   if (free_s)
 180     free (s);
 181
 182   return str;
 183 }
 184
 185
 186 /* Create a tree node for the string length if it is constant.  */
 187
 188 void
 189 gfc_conv_const_charlen (gfc_charlen * cl)
 190 {
 191   if (!cl || cl->backend_decl)
 192     return;
 193
 194   if (cl->length && cl->length->expr_type == EXPR_CONSTANT)
 195     {
 196       cl->backend_decl = gfc_conv_mpz_to_tree (cl->length->value.integer,
 197                                                cl->length->ts.kind);
 198       cl->backend_decl = fold_convert (gfc_charlen_type_node,
 199                                         cl->backend_decl);
 200     }
 201 }
 202
 203 void
 204 gfc_init_constants (void)
 205 {
 206   int n;
 207
 208   for (n = 0; n <= GFC_MAX_DIMENSIONS; n++)
 209     gfc_rank_cst[n] = build_int_cst (gfc_array_index_type, n);
 210 }
 211
 212 /* Converts a GMP integer into a backend tree node.  */
 213
 214 tree
 215 gfc_conv_mpz_to_tree (mpz_t i, int kind)
 216 {
 217   wide_int val = wi::from_mpz (gfc_get_int_type (kind), i, true);
 218   return wide_int_to_tree (gfc_get_int_type (kind), val);
 219 }
 220
 221 /* Converts a backend tree into a GMP integer.  */
 222
 223 void
 224 gfc_conv_tree_to_mpz (mpz_t i, tree source)
 225 {
 226   wi::to_mpz (source, i, TYPE_SIGN (TREE_TYPE (source)));
 227 }
 228
 229 /* Converts a real constant into backend form.  */
 230
 231 tree
 232 gfc_conv_mpfr_to_tree (mpfr_t f, int kind, int is_snan)
 233 {
 234   tree type;
 235   int n;
 236   REAL_VALUE_TYPE real;
 237
 238   n = gfc_validate_kind (BT_REAL, kind, false);
 239   gcc_assert (gfc_real_kinds[n].radix == 2);
 240
 241   type = gfc_get_real_type (kind);
 242   if (mpfr_nan_p (f) && is_snan)
 243      real_from_string (&real, "SNaN");
 244   else
 245     real_from_mpfr (&real, f, type, GFC_RND_MODE);
 246
 247   return build_real (type, real);
 248 }
 249
 250 /* Returns a real constant that is +Infinity if the target
 251    supports infinities for this floating-point mode, and
 252    +HUGE_VAL otherwise (the largest representable number).  */
 253
 254 tree
 255 gfc_build_inf_or_huge (tree type, int kind)
 256 {
 257   if (HONOR_INFINITIES (TYPE_MODE (type)))
 258     {
 259       REAL_VALUE_TYPE real;
 260       real_inf (&real);
 261       return build_real (type, real);
 262     }
 263   else
 264     {
 265       int k = gfc_validate_kind (BT_REAL, kind, false);
 266       return gfc_conv_mpfr_to_tree (gfc_real_kinds[k].huge, kind, 0);
 267     }
 268 }
 269
 270 /* Returns a floating-point NaN of a given type.  */
 271
 272 tree
 273 gfc_build_nan (tree type, const char *str)
 274 {
 275   REAL_VALUE_TYPE real;
 276   real_nan (&real, str, 1, TYPE_MODE (type));
 277   return build_real (type, real);
 278 }
 279
 280 /* Converts a backend tree into a real constant.  */
 281
 282 void
 283 gfc_conv_tree_to_mpfr (mpfr_ptr f, tree source)
 284 {
 285   mpfr_from_real (f, TREE_REAL_CST_PTR (source), GFC_RND_MODE);
 286 }
 287
 288 /* Translate any literal constant to a tree.  Constants never have
 289    pre or post chains.  Character literal constants are special
 290    special because they have a value and a length, so they cannot be
 291    returned as a single tree.  It is up to the caller to set the
 292    length somewhere if necessary.
 293
 294    Returns the translated constant, or aborts if it gets a type it
 295    can't handle.  */
 296
 297 tree
 298 gfc_conv_constant_to_tree (gfc_expr * expr)
 299 {
 300   tree res;
 301
 302   gcc_assert (expr->expr_type == EXPR_CONSTANT);
 303
 304   /* If it is has a prescribed memory representation, we build a string
 305      constant and VIEW_CONVERT to its type.  */
 306
 307   switch (expr->ts.type)
 308     {
 309     case BT_INTEGER:
 310       if (expr->representation.string)
 311         return fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 312                          gfc_get_int_type (expr->ts.kind),
 313                          gfc_build_string_const (expr->representation.length,
 314                                                  expr->representation.string));
 315       else
 316         return gfc_conv_mpz_to_tree (expr->value.integer, expr->ts.kind);
 317
 318     case BT_REAL:
 319       if (expr->representation.string)
 320         return fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 321                          gfc_get_real_type (expr->ts.kind),
 322                          gfc_build_string_const (expr->representation.length,
 323                                                  expr->representation.string));
 324       else
 325         return gfc_conv_mpfr_to_tree (expr->value.real, expr->ts.kind, expr->is_snan);
 326
 327     case BT_LOGICAL:
 328       if (expr->representation.string)
 329         {
 330           tree tmp = fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 331                         gfc_get_int_type (expr->ts.kind),
 332                         gfc_build_string_const (expr->representation.length,
 333                                                 expr->representation.string));
 334           if (!integer_zerop (tmp) && !integer_onep (tmp))
 335             gfc_warning (0, "Assigning value other than 0 or 1 to LOGICAL"
 336                          " has undefined result at %L", &expr->where);
 337           return fold_convert (gfc_get_logical_type (expr->ts.kind), tmp);
 338         }
 339       else
 340         return build_int_cst (gfc_get_logical_type (expr->ts.kind),
 341                               expr->value.logical);
 342
 343     case BT_COMPLEX:
 344       if (expr->representation.string)
 345         return fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 346                          gfc_get_complex_type (expr->ts.kind),
 347                          gfc_build_string_const (expr->representation.length,
 348                                                  expr->representation.string));
 349       else
 350         {
 351           tree real = gfc_conv_mpfr_to_tree (mpc_realref (expr->value.complex),
 352                                           expr->ts.kind, expr->is_snan);
 353           tree imag = gfc_conv_mpfr_to_tree (mpc_imagref (expr->value.complex),
 354                                           expr->ts.kind, expr->is_snan);
 355
 356           return build_complex (gfc_typenode_for_spec (&expr->ts),
 357                                 real, imag);
 358         }
 359
 360     case BT_CHARACTER:
 361       res = gfc_build_wide_string_const (expr->ts.kind,
 362                                          expr->value.character.length,
 363                                          expr->value.character.string);
 364       return res;
 365
 366     case BT_HOLLERITH:
 367       return gfc_build_string_const (expr->representation.length,
 368                                      expr->representation.string);
 369
 370     default:
 371       fatal_error (input_location,
 372                    "gfc_conv_constant_to_tree(): invalid type: %s",
 373                    gfc_typename (&expr->ts));
 374     }
 375 }
 376
 377
 378 /* Like gfc_conv_constant_to_tree, but for a simplified expression.
 379    We can handle character literal constants here as well.  */
 380
 381 void
 382 gfc_conv_constant (gfc_se * se, gfc_expr * expr)
 383 {
 384   gfc_ss *ss;
 385
 386   /* We may be receiving an expression for C_NULL_PTR or C_NULL_FUNPTR.  If
 387      so, the expr_type will not yet be an EXPR_CONSTANT.  We need to make
 388      it so here.  */
 389   if (expr->ts.type == BT_DERIVED && expr->ts.u.derived
 390       && expr->ts.u.derived->attr.is_iso_c)
 391     {
 392       if (expr->symtree->n.sym->intmod_sym_id == ISOCBINDING_NULL_PTR
 393           || expr->symtree->n.sym->intmod_sym_id == ISOCBINDING_NULL_FUNPTR)
 394         {
 395           /* Create a new EXPR_CONSTANT expression for our local uses.  */
 396           expr = gfc_get_int_expr (gfc_default_integer_kind, NULL, 0);
 397         }
 398     }
 399
 400   if (expr->expr_type != EXPR_CONSTANT)
 401     {
 402       gfc_expr *e = gfc_get_int_expr (gfc_default_integer_kind, NULL, 0);
 403       gfc_error ("non-constant initialization expression at %L", &expr->where);
 404       se->expr = gfc_conv_constant_to_tree (e);
 405       return;
 406     }
 407
 408   ss = se->ss;
 409   if (ss != NULL)
 410     {
 411       gfc_ss_info *ss_info;
 412
 413       ss_info = ss->info;
 414       gcc_assert (ss != gfc_ss_terminator);
 415       gcc_assert (ss_info->type == GFC_SS_SCALAR);
 416       gcc_assert (ss_info->expr == expr);
 417
 418       se->expr = ss_info->data.scalar.value;
 419       se->string_length = ss_info->string_length;
 420       gfc_advance_se_ss_chain (se);
 421       return;
 422     }
 423
 424   /* Translate the constant and put it in the simplifier structure.  */
 425   se->expr = gfc_conv_constant_to_tree (expr);
 426
 427   /* If this is a CHARACTER string, set its length in the simplifier
 428      structure, too.  */
 429   if (expr->ts.type == BT_CHARACTER)
 430     se->string_length = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (se->expr)));
 431 }