gcc/fortran/trans-const.c

   1 /* Translation of constants
   2    Copyright (C) 2002-2014 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 "stor-layout.h"
  28 #include "realmpfr.h"
  29 #include "diagnostic-core.h"    /* For fatal_error.  */
  30 #include "double-int.h"
  31 #include "gfortran.h"
  32 #include "trans.h"
  33 #include "trans-const.h"
  34 #include "trans-types.h"
  35 #include "target-memory.h"
  36 #include "wide-int.h"
  37
  38 tree gfc_rank_cst[GFC_MAX_DIMENSIONS + 1];
  39
  40 /* Build a constant with given type from an int_cst.  */
  41
  42 tree
  43 gfc_build_const (tree type, tree intval)
  44 {
  45   tree val;
  46   tree zero;
  47
  48   switch (TREE_CODE (type))
  49     {
  50     case INTEGER_TYPE:
  51       val = convert (type, intval);
  52       break;
  53
  54     case REAL_TYPE:
  55       val = build_real_from_int_cst (type, intval);
  56       break;
  57
  58     case COMPLEX_TYPE:
  59       val = build_real_from_int_cst (TREE_TYPE (type), intval);
  60       zero = build_real_from_int_cst (TREE_TYPE (type), integer_zero_node);
  61       val = build_complex (type, val, zero);
  62       break;
  63
  64     default:
  65       gcc_unreachable ();
  66     }
  67   return val;
  68 }
  69
  70 /* Build a string constant with C char type.  */
  71
  72 tree
  73 gfc_build_string_const (int length, const char *s)
  74 {
  75   tree str;
  76   tree len;
  77
  78   str = build_string (length, s);
  79   len = size_int (length);
  80   TREE_TYPE (str) =
  81     build_array_type (gfc_character1_type_node,
  82                       build_range_type (gfc_charlen_type_node,
  83                                         size_one_node, len));
  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   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   int 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 /* Converts a backend tree into a GMP integer.  */
 209
 210 void
 211 gfc_conv_tree_to_mpz (mpz_t i, tree source)
 212 {
 213   wi::to_mpz (source, i, TYPE_SIGN (TREE_TYPE (source)));
 214 }
 215
 216 /* Converts a real constant into backend form.  */
 217
 218 tree
 219 gfc_conv_mpfr_to_tree (mpfr_t f, int kind, int is_snan)
 220 {
 221   tree type;
 222   int n;
 223   REAL_VALUE_TYPE real;
 224
 225   n = gfc_validate_kind (BT_REAL, kind, false);
 226   gcc_assert (gfc_real_kinds[n].radix == 2);
 227
 228   type = gfc_get_real_type (kind);
 229   if (mpfr_nan_p (f) && is_snan)
 230      real_from_string (&real, "SNaN");
 231   else
 232     real_from_mpfr (&real, f, type, GFC_RND_MODE);
 233
 234   return build_real (type, real);
 235 }
 236
 237 /* Returns a real constant that is +Infinity if the target
 238    supports infinities for this floating-point mode, and
 239    +HUGE_VAL otherwise (the largest representable number).  */
 240
 241 tree
 242 gfc_build_inf_or_huge (tree type, int kind)
 243 {
 244   if (HONOR_INFINITIES (TYPE_MODE (type)))
 245     {
 246       REAL_VALUE_TYPE real;
 247       real_inf (&real);
 248       return build_real (type, real);
 249     }
 250   else
 251     {
 252       int k = gfc_validate_kind (BT_REAL, kind, false);
 253       return gfc_conv_mpfr_to_tree (gfc_real_kinds[k].huge, kind, 0);
 254     }
 255 }
 256
 257 /* Converts a backend tree into a real constant.  */
 258
 259 void
 260 gfc_conv_tree_to_mpfr (mpfr_ptr f, tree source)
 261 {
 262   mpfr_from_real (f, TREE_REAL_CST_PTR (source), GFC_RND_MODE);
 263 }
 264
 265 /* Translate any literal constant to a tree.  Constants never have
 266    pre or post chains.  Character literal constants are special
 267    special because they have a value and a length, so they cannot be
 268    returned as a single tree.  It is up to the caller to set the
 269    length somewhere if necessary.
 270
 271    Returns the translated constant, or aborts if it gets a type it
 272    can't handle.  */
 273
 274 tree
 275 gfc_conv_constant_to_tree (gfc_expr * expr)
 276 {
 277   tree res;
 278
 279   gcc_assert (expr->expr_type == EXPR_CONSTANT);
 280
 281   /* If it is has a prescribed memory representation, we build a string
 282      constant and VIEW_CONVERT to its type.  */
 283
 284   switch (expr->ts.type)
 285     {
 286     case BT_INTEGER:
 287       if (expr->representation.string)
 288         return fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 289                          gfc_get_int_type (expr->ts.kind),
 290                          gfc_build_string_const (expr->representation.length,
 291                                                  expr->representation.string));
 292       else
 293         return gfc_conv_mpz_to_tree (expr->value.integer, expr->ts.kind);
 294
 295     case BT_REAL:
 296       if (expr->representation.string)
 297         return fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 298                          gfc_get_real_type (expr->ts.kind),
 299                          gfc_build_string_const (expr->representation.length,
 300                                                  expr->representation.string));
 301       else
 302         return gfc_conv_mpfr_to_tree (expr->value.real, expr->ts.kind, expr->is_snan);
 303
 304     case BT_LOGICAL:
 305       if (expr->representation.string)
 306         {
 307           tree tmp = fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 308                         gfc_get_int_type (expr->ts.kind),
 309                         gfc_build_string_const (expr->representation.length,
 310                                                 expr->representation.string));
 311           if (!integer_zerop (tmp) && !integer_onep (tmp))
 312             gfc_warning ("Assigning value other than 0 or 1 to LOGICAL"
 313                          " has undefined result at %L", &expr->where);
 314           return fold_convert (gfc_get_logical_type (expr->ts.kind), tmp);
 315         }
 316       else
 317         return build_int_cst (gfc_get_logical_type (expr->ts.kind),
 318                               expr->value.logical);
 319
 320     case BT_COMPLEX:
 321       if (expr->representation.string)
 322         return fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 323                          gfc_get_complex_type (expr->ts.kind),
 324                          gfc_build_string_const (expr->representation.length,
 325                                                  expr->representation.string));
 326       else
 327         {
 328           tree real = gfc_conv_mpfr_to_tree (mpc_realref (expr->value.complex),
 329                                           expr->ts.kind, expr->is_snan);
 330           tree imag = gfc_conv_mpfr_to_tree (mpc_imagref (expr->value.complex),
 331                                           expr->ts.kind, expr->is_snan);
 332
 333           return build_complex (gfc_typenode_for_spec (&expr->ts),
 334                                 real, imag);
 335         }
 336
 337     case BT_CHARACTER:
 338       res = gfc_build_wide_string_const (expr->ts.kind,
 339                                          expr->value.character.length,
 340                                          expr->value.character.string);
 341       return res;
 342
 343     case BT_HOLLERITH:
 344       return gfc_build_string_const (expr->representation.length,
 345                                      expr->representation.string);
 346
 347     default:
 348       fatal_error ("gfc_conv_constant_to_tree(): invalid type: %s",
 349                    gfc_typename (&expr->ts));
 350     }
 351 }
 352
 353
 354 /* Like gfc_conv_constant_to_tree, but for a simplified expression.
 355    We can handle character literal constants here as well.  */
 356
 357 void
 358 gfc_conv_constant (gfc_se * se, gfc_expr * expr)
 359 {
 360   gfc_ss *ss;
 361
 362   /* We may be receiving an expression for C_NULL_PTR or C_NULL_FUNPTR.  If
 363      so, the expr_type will not yet be an EXPR_CONSTANT.  We need to make
 364      it so here.  */
 365   if (expr->ts.type == BT_DERIVED && expr->ts.u.derived
 366       && expr->ts.u.derived->attr.is_iso_c)
 367     {
 368       if (expr->symtree->n.sym->intmod_sym_id == ISOCBINDING_NULL_PTR
 369           || expr->symtree->n.sym->intmod_sym_id == ISOCBINDING_NULL_FUNPTR)
 370         {
 371           /* Create a new EXPR_CONSTANT expression for our local uses.  */
 372           expr = gfc_get_int_expr (gfc_default_integer_kind, NULL, 0);
 373         }
 374     }
 375
 376   if (expr->expr_type != EXPR_CONSTANT)
 377     {
 378       gfc_expr *e = gfc_get_int_expr (gfc_default_integer_kind, NULL, 0);
 379       gfc_error ("non-constant initialization expression at %L", &expr->where);
 380       se->expr = gfc_conv_constant_to_tree (e);
 381       return;
 382     }
 383
 384   ss = se->ss;
 385   if (ss != NULL)
 386     {
 387       gfc_ss_info *ss_info;
 388
 389       ss_info = ss->info;
 390       gcc_assert (ss != gfc_ss_terminator);
 391       gcc_assert (ss_info->type == GFC_SS_SCALAR);
 392       gcc_assert (ss_info->expr == expr);
 393
 394       se->expr = ss_info->data.scalar.value;
 395       se->string_length = ss_info->string_length;
 396       gfc_advance_se_ss_chain (se);
 397       return;
 398     }
 399
 400   /* Translate the constant and put it in the simplifier structure.  */
 401   se->expr = gfc_conv_constant_to_tree (expr);
 402
 403   /* If this is a CHARACTER string, set its length in the simplifier
 404      structure, too.  */
 405   if (expr->ts.type == BT_CHARACTER)
 406     se->string_length = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (se->expr)));
 407 }