gcc/fortran/trans-const.c

   1 /* Translation of constants
   2    Copyright (C) 2002-2017 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 "diagnostic-core.h"    /* For fatal_error.  */
  30 #include "fold-const.h"
  31 #include "stor-layout.h"
  32 #include "realmpfr.h"
  33 #include "trans-const.h"
  34 #include "trans-types.h"
  35 #include "target-memory.h"
  36
  37 tree gfc_rank_cst[GFC_MAX_DIMENSIONS + 1];
  38
  39 /* Build a constant with given type from an int_cst.  */
  40
  41 tree
  42 gfc_build_const (tree type, tree intval)
  43 {
  44   tree val;
  45   tree zero;
  46
  47   switch (TREE_CODE (type))
  48     {
  49     case INTEGER_TYPE:
  50       val = convert (type, intval);
  51       break;
  52
  53     case REAL_TYPE:
  54       val = build_real_from_int_cst (type, intval);
  55       break;
  56
  57     case COMPLEX_TYPE:
  58       val = build_real_from_int_cst (TREE_TYPE (type), intval);
  59       zero = build_real_from_int_cst (TREE_TYPE (type), integer_zero_node);
  60       val = build_complex (type, val, zero);
  61       break;
  62
  63     default:
  64       gcc_unreachable ();
  65     }
  66   return val;
  67 }
  68
  69 /* Build a string constant with C char type.  */
  70
  71 tree
  72 gfc_build_string_const (int length, const char *s)
  73 {
  74   tree str;
  75   tree len;
  76
  77   str = build_string (length, s);
  78   len = size_int (length);
  79   TREE_TYPE (str) =
  80     build_array_type (gfc_character1_type_node,
  81                       build_range_type (gfc_charlen_type_node,
  82                                         size_one_node, len));
  83   TYPE_STRING_FLAG (TREE_TYPE (str)) = 1;
  84   return str;
  85 }
  86
  87
  88 /* Build a string constant with a type given by its kind; take care of
  89    non-default character kinds.  */
  90
  91 tree
  92 gfc_build_wide_string_const (int kind, int length, const gfc_char_t *string)
  93 {
  94   int i;
  95   tree str, len;
  96   size_t size;
  97   char *s;
  98
  99   i = gfc_validate_kind (BT_CHARACTER, kind, false);
 100   size = length * gfc_character_kinds[i].bit_size / 8;
 101
 102   s = XCNEWVAR (char, size);
 103   gfc_encode_character (kind, length, string, (unsigned char *) s, size);
 104
 105   str = build_string (size, s);
 106   free (s);
 107
 108   len = size_int (length);
 109   TREE_TYPE (str) =
 110     build_array_type (gfc_get_char_type (kind),
 111                       build_range_type (gfc_charlen_type_node,
 112                                         size_one_node, len));
 113   TYPE_STRING_FLAG (TREE_TYPE (str)) = 1;
 114   return str;
 115 }
 116
 117
 118 /* Build a Fortran character constant from a zero-terminated string.
 119    There a two version of this function, one that translates the string
 120    and one that doesn't.  */
 121 tree
 122 gfc_build_cstring_const (const char *string)
 123 {
 124   return gfc_build_string_const (strlen (string) + 1, string);
 125 }
 126
 127 tree
 128 gfc_build_localized_cstring_const (const char *msgid)
 129 {
 130   const char *localized = _(msgid);
 131   return gfc_build_string_const (strlen (localized) + 1, localized);
 132 }
 133
 134
 135 /* Return a string constant with the given length.  Used for static
 136    initializers.  The constant will be padded or truncated to match
 137    length.  */
 138
 139 tree
 140 gfc_conv_string_init (tree length, gfc_expr * expr)
 141 {
 142   gfc_char_t *s;
 143   HOST_WIDE_INT len;
 144   int slen;
 145   tree str;
 146   bool free_s = false;
 147
 148   gcc_assert (expr->expr_type == EXPR_CONSTANT);
 149   gcc_assert (expr->ts.type == BT_CHARACTER);
 150   gcc_assert (tree_fits_uhwi_p (length));
 151
 152   len = TREE_INT_CST_LOW (length);
 153   slen = expr->value.character.length;
 154
 155   if (len > slen)
 156     {
 157       s = gfc_get_wide_string (len);
 158       memcpy (s, expr->value.character.string, slen * sizeof (gfc_char_t));
 159       gfc_wide_memset (&s[slen], ' ', len - slen);
 160       free_s = true;
 161     }
 162   else
 163     s = expr->value.character.string;
 164
 165   str = gfc_build_wide_string_const (expr->ts.kind, len, s);
 166
 167   if (free_s)
 168     free (s);
 169
 170   return str;
 171 }
 172
 173
 174 /* Create a tree node for the string length if it is constant.  */
 175
 176 void
 177 gfc_conv_const_charlen (gfc_charlen * cl)
 178 {
 179   if (!cl || cl->backend_decl)
 180     return;
 181
 182   if (cl->length && cl->length->expr_type == EXPR_CONSTANT)
 183     {
 184       cl->backend_decl = gfc_conv_mpz_to_tree (cl->length->value.integer,
 185                                                cl->length->ts.kind);
 186       cl->backend_decl = fold_convert (gfc_charlen_type_node,
 187                                         cl->backend_decl);
 188     }
 189 }
 190
 191 void
 192 gfc_init_constants (void)
 193 {
 194   int n;
 195
 196   for (n = 0; n <= GFC_MAX_DIMENSIONS; n++)
 197     gfc_rank_cst[n] = build_int_cst (gfc_array_index_type, n);
 198 }
 199
 200 /* Converts a GMP integer into a backend tree node.  */
 201
 202 tree
 203 gfc_conv_mpz_to_tree (mpz_t i, int kind)
 204 {
 205   wide_int val = wi::from_mpz (gfc_get_int_type (kind), i, true);
 206   return wide_int_to_tree (gfc_get_int_type (kind), val);
 207 }
 208
 209 /* Converts a backend tree into a GMP integer.  */
 210
 211 void
 212 gfc_conv_tree_to_mpz (mpz_t i, tree source)
 213 {
 214   wi::to_mpz (source, i, TYPE_SIGN (TREE_TYPE (source)));
 215 }
 216
 217 /* Converts a real constant into backend form.  */
 218
 219 tree
 220 gfc_conv_mpfr_to_tree (mpfr_t f, int kind, int is_snan)
 221 {
 222   tree type;
 223   int n;
 224   REAL_VALUE_TYPE real;
 225
 226   n = gfc_validate_kind (BT_REAL, kind, false);
 227   gcc_assert (gfc_real_kinds[n].radix == 2);
 228
 229   type = gfc_get_real_type (kind);
 230   if (mpfr_nan_p (f) && is_snan)
 231      real_from_string (&real, "SNaN");
 232   else
 233     real_from_mpfr (&real, f, type, GFC_RND_MODE);
 234
 235   return build_real (type, real);
 236 }
 237
 238 /* Returns a real constant that is +Infinity if the target
 239    supports infinities for this floating-point mode, and
 240    +HUGE_VAL otherwise (the largest representable number).  */
 241
 242 tree
 243 gfc_build_inf_or_huge (tree type, int kind)
 244 {
 245   if (HONOR_INFINITIES (TYPE_MODE (type)))
 246     {
 247       REAL_VALUE_TYPE real;
 248       real_inf (&real);
 249       return build_real (type, real);
 250     }
 251   else
 252     {
 253       int k = gfc_validate_kind (BT_REAL, kind, false);
 254       return gfc_conv_mpfr_to_tree (gfc_real_kinds[k].huge, kind, 0);
 255     }
 256 }
 257
 258 /* Returns a floating-point NaN of a given type.  */
 259
 260 tree
 261 gfc_build_nan (tree type, const char *str)
 262 {
 263   REAL_VALUE_TYPE real;
 264   real_nan (&real, str, 1, TYPE_MODE (type));
 265   return build_real (type, real);
 266 }
 267
 268 /* Converts a backend tree into a real constant.  */
 269
 270 void
 271 gfc_conv_tree_to_mpfr (mpfr_ptr f, tree source)
 272 {
 273   mpfr_from_real (f, TREE_REAL_CST_PTR (source), GFC_RND_MODE);
 274 }
 275
 276 /* Translate any literal constant to a tree.  Constants never have
 277    pre or post chains.  Character literal constants are special
 278    special because they have a value and a length, so they cannot be
 279    returned as a single tree.  It is up to the caller to set the
 280    length somewhere if necessary.
 281
 282    Returns the translated constant, or aborts if it gets a type it
 283    can't handle.  */
 284
 285 tree
 286 gfc_conv_constant_to_tree (gfc_expr * expr)
 287 {
 288   tree res;
 289
 290   gcc_assert (expr->expr_type == EXPR_CONSTANT);
 291
 292   /* If it is has a prescribed memory representation, we build a string
 293      constant and VIEW_CONVERT to its type.  */
 294
 295   switch (expr->ts.type)
 296     {
 297     case BT_INTEGER:
 298       if (expr->representation.string)
 299         return fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 300                          gfc_get_int_type (expr->ts.kind),
 301                          gfc_build_string_const (expr->representation.length,
 302                                                  expr->representation.string));
 303       else
 304         return gfc_conv_mpz_to_tree (expr->value.integer, expr->ts.kind);
 305
 306     case BT_REAL:
 307       if (expr->representation.string)
 308         return fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 309                          gfc_get_real_type (expr->ts.kind),
 310                          gfc_build_string_const (expr->representation.length,
 311                                                  expr->representation.string));
 312       else
 313         return gfc_conv_mpfr_to_tree (expr->value.real, expr->ts.kind, expr->is_snan);
 314
 315     case BT_LOGICAL:
 316       if (expr->representation.string)
 317         {
 318           tree tmp = fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 319                         gfc_get_int_type (expr->ts.kind),
 320                         gfc_build_string_const (expr->representation.length,
 321                                                 expr->representation.string));
 322           if (!integer_zerop (tmp) && !integer_onep (tmp))
 323             gfc_warning (0, "Assigning value other than 0 or 1 to LOGICAL"
 324                          " has undefined result at %L", &expr->where);
 325           return fold_convert (gfc_get_logical_type (expr->ts.kind), tmp);
 326         }
 327       else
 328         return build_int_cst (gfc_get_logical_type (expr->ts.kind),
 329                               expr->value.logical);
 330
 331     case BT_COMPLEX:
 332       if (expr->representation.string)
 333         return fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 334                          gfc_get_complex_type (expr->ts.kind),
 335                          gfc_build_string_const (expr->representation.length,
 336                                                  expr->representation.string));
 337       else
 338         {
 339           tree real = gfc_conv_mpfr_to_tree (mpc_realref (expr->value.complex),
 340                                           expr->ts.kind, expr->is_snan);
 341           tree imag = gfc_conv_mpfr_to_tree (mpc_imagref (expr->value.complex),
 342                                           expr->ts.kind, expr->is_snan);
 343
 344           return build_complex (gfc_typenode_for_spec (&expr->ts),
 345                                 real, imag);
 346         }
 347
 348     case BT_CHARACTER:
 349       res = gfc_build_wide_string_const (expr->ts.kind,
 350                                          expr->value.character.length,
 351                                          expr->value.character.string);
 352       return res;
 353
 354     case BT_HOLLERITH:
 355       return gfc_build_string_const (expr->representation.length,
 356                                      expr->representation.string);
 357
 358     default:
 359       fatal_error (input_location,
 360                    "gfc_conv_constant_to_tree(): invalid type: %s",
 361                    gfc_typename (&expr->ts));
 362     }
 363 }
 364
 365
 366 /* Like gfc_conv_constant_to_tree, but for a simplified expression.
 367    We can handle character literal constants here as well.  */
 368
 369 void
 370 gfc_conv_constant (gfc_se * se, gfc_expr * expr)
 371 {
 372   gfc_ss *ss;
 373
 374   /* We may be receiving an expression for C_NULL_PTR or C_NULL_FUNPTR.  If
 375      so, the expr_type will not yet be an EXPR_CONSTANT.  We need to make
 376      it so here.  */
 377   if (expr->ts.type == BT_DERIVED && expr->ts.u.derived
 378       && expr->ts.u.derived->attr.is_iso_c)
 379     {
 380       if (expr->symtree->n.sym->intmod_sym_id == ISOCBINDING_NULL_PTR
 381           || expr->symtree->n.sym->intmod_sym_id == ISOCBINDING_NULL_FUNPTR)
 382         {
 383           /* Create a new EXPR_CONSTANT expression for our local uses.  */
 384           expr = gfc_get_int_expr (gfc_default_integer_kind, NULL, 0);
 385         }
 386     }
 387
 388   if (expr->expr_type != EXPR_CONSTANT)
 389     {
 390       gfc_expr *e = gfc_get_int_expr (gfc_default_integer_kind, NULL, 0);
 391       gfc_error ("non-constant initialization expression at %L", &expr->where);
 392       se->expr = gfc_conv_constant_to_tree (e);
 393       return;
 394     }
 395
 396   ss = se->ss;
 397   if (ss != NULL)
 398     {
 399       gfc_ss_info *ss_info;
 400
 401       ss_info = ss->info;
 402       gcc_assert (ss != gfc_ss_terminator);
 403       gcc_assert (ss_info->type == GFC_SS_SCALAR);
 404       gcc_assert (ss_info->expr == expr);
 405
 406       se->expr = ss_info->data.scalar.value;
 407       se->string_length = ss_info->string_length;
 408       gfc_advance_se_ss_chain (se);
 409       return;
 410     }
 411
 412   /* Translate the constant and put it in the simplifier structure.  */
 413   se->expr = gfc_conv_constant_to_tree (expr);
 414
 415   /* If this is a CHARACTER string, set its length in the simplifier
 416      structure, too.  */
 417   if (expr->ts.type == BT_CHARACTER)
 418     se->string_length = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (se->expr)));
 419 }