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 "gfortran.h"
  27 #include "tree.h"
  28 #include "stor-layout.h"
  29 #include "realmpfr.h"
  30 #include "diagnostic-core.h"    /* For fatal_error.  */
  31 #include "double-int.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   TYPE_STRING_FLAG (TREE_TYPE (str)) = 1;
  85   return str;
  86 }
  87
  88
  89 /* Build a string constant with a type given by its kind; take care of
  90    non-default character kinds.  */
  91
  92 tree
  93 gfc_build_wide_string_const (int kind, int length, const gfc_char_t *string)
  94 {
  95   int i;
  96   tree str, len;
  97   size_t size;
  98   char *s;
  99
 100   i = gfc_validate_kind (BT_CHARACTER, kind, false);
 101   size = length * gfc_character_kinds[i].bit_size / 8;
 102
 103   s = XCNEWVAR (char, size);
 104   gfc_encode_character (kind, length, string, (unsigned char *) s, size);
 105
 106   str = build_string (size, s);
 107   free (s);
 108
 109   len = size_int (length);
 110   TREE_TYPE (str) =
 111     build_array_type (gfc_get_char_type (kind),
 112                       build_range_type (gfc_charlen_type_node,
 113                                         size_one_node, len));
 114   TYPE_STRING_FLAG (TREE_TYPE (str)) = 1;
 115   return str;
 116 }
 117
 118
 119 /* Build a Fortran character constant from a zero-terminated string.
 120    There a two version of this function, one that translates the string
 121    and one that doesn't.  */
 122 tree
 123 gfc_build_cstring_const (const char *string)
 124 {
 125   return gfc_build_string_const (strlen (string) + 1, string);
 126 }
 127
 128 tree
 129 gfc_build_localized_cstring_const (const char *msgid)
 130 {
 131   const char *localized = _(msgid);
 132   return gfc_build_string_const (strlen (localized) + 1, localized);
 133 }
 134
 135
 136 /* Return a string constant with the given length.  Used for static
 137    initializers.  The constant will be padded or truncated to match
 138    length.  */
 139
 140 tree
 141 gfc_conv_string_init (tree length, gfc_expr * expr)
 142 {
 143   gfc_char_t *s;
 144   HOST_WIDE_INT len;
 145   int slen;
 146   tree str;
 147   bool free_s = false;
 148
 149   gcc_assert (expr->expr_type == EXPR_CONSTANT);
 150   gcc_assert (expr->ts.type == BT_CHARACTER);
 151   gcc_assert (tree_fits_uhwi_p (length));
 152
 153   len = TREE_INT_CST_LOW (length);
 154   slen = expr->value.character.length;
 155
 156   if (len > slen)
 157     {
 158       s = gfc_get_wide_string (len);
 159       memcpy (s, expr->value.character.string, slen * sizeof (gfc_char_t));
 160       gfc_wide_memset (&s[slen], ' ', len - slen);
 161       free_s = true;
 162     }
 163   else
 164     s = expr->value.character.string;
 165
 166   str = gfc_build_wide_string_const (expr->ts.kind, len, s);
 167
 168   if (free_s)
 169     free (s);
 170
 171   return str;
 172 }
 173
 174
 175 /* Create a tree node for the string length if it is constant.  */
 176
 177 void
 178 gfc_conv_const_charlen (gfc_charlen * cl)
 179 {
 180   if (!cl || cl->backend_decl)
 181     return;
 182
 183   if (cl->length && cl->length->expr_type == EXPR_CONSTANT)
 184     {
 185       cl->backend_decl = gfc_conv_mpz_to_tree (cl->length->value.integer,
 186                                                cl->length->ts.kind);
 187       cl->backend_decl = fold_convert (gfc_charlen_type_node,
 188                                         cl->backend_decl);
 189     }
 190 }
 191
 192 void
 193 gfc_init_constants (void)
 194 {
 195   int n;
 196
 197   for (n = 0; n <= GFC_MAX_DIMENSIONS; n++)
 198     gfc_rank_cst[n] = build_int_cst (gfc_array_index_type, n);
 199 }
 200
 201 /* Converts a GMP integer into a backend tree node.  */
 202
 203 tree
 204 gfc_conv_mpz_to_tree (mpz_t i, int kind)
 205 {
 206   wide_int val = wi::from_mpz (gfc_get_int_type (kind), i, true);
 207   return wide_int_to_tree (gfc_get_int_type (kind), val);
 208 }
 209
 210 /* Converts a backend tree into a GMP integer.  */
 211
 212 void
 213 gfc_conv_tree_to_mpz (mpz_t i, tree source)
 214 {
 215   wi::to_mpz (source, i, TYPE_SIGN (TREE_TYPE (source)));
 216 }
 217
 218 /* Converts a real constant into backend form.  */
 219
 220 tree
 221 gfc_conv_mpfr_to_tree (mpfr_t f, int kind, int is_snan)
 222 {
 223   tree type;
 224   int n;
 225   REAL_VALUE_TYPE real;
 226
 227   n = gfc_validate_kind (BT_REAL, kind, false);
 228   gcc_assert (gfc_real_kinds[n].radix == 2);
 229
 230   type = gfc_get_real_type (kind);
 231   if (mpfr_nan_p (f) && is_snan)
 232      real_from_string (&real, "SNaN");
 233   else
 234     real_from_mpfr (&real, f, type, GFC_RND_MODE);
 235
 236   return build_real (type, real);
 237 }
 238
 239 /* Returns a real constant that is +Infinity if the target
 240    supports infinities for this floating-point mode, and
 241    +HUGE_VAL otherwise (the largest representable number).  */
 242
 243 tree
 244 gfc_build_inf_or_huge (tree type, int kind)
 245 {
 246   if (HONOR_INFINITIES (TYPE_MODE (type)))
 247     {
 248       REAL_VALUE_TYPE real;
 249       real_inf (&real);
 250       return build_real (type, real);
 251     }
 252   else
 253     {
 254       int k = gfc_validate_kind (BT_REAL, kind, false);
 255       return gfc_conv_mpfr_to_tree (gfc_real_kinds[k].huge, kind, 0);
 256     }
 257 }
 258
 259 /* Returns a floating-point NaN of a given type.  */
 260
 261 tree
 262 gfc_build_nan (tree type, const char *str)
 263 {
 264   REAL_VALUE_TYPE real;
 265   real_nan (&real, str, 1, TYPE_MODE (type));
 266   return build_real (type, real);
 267 }
 268
 269 /* Converts a backend tree into a real constant.  */
 270
 271 void
 272 gfc_conv_tree_to_mpfr (mpfr_ptr f, tree source)
 273 {
 274   mpfr_from_real (f, TREE_REAL_CST_PTR (source), GFC_RND_MODE);
 275 }
 276
 277 /* Translate any literal constant to a tree.  Constants never have
 278    pre or post chains.  Character literal constants are special
 279    special because they have a value and a length, so they cannot be
 280    returned as a single tree.  It is up to the caller to set the
 281    length somewhere if necessary.
 282
 283    Returns the translated constant, or aborts if it gets a type it
 284    can't handle.  */
 285
 286 tree
 287 gfc_conv_constant_to_tree (gfc_expr * expr)
 288 {
 289   tree res;
 290
 291   gcc_assert (expr->expr_type == EXPR_CONSTANT);
 292
 293   /* If it is has a prescribed memory representation, we build a string
 294      constant and VIEW_CONVERT to its type.  */
 295
 296   switch (expr->ts.type)
 297     {
 298     case BT_INTEGER:
 299       if (expr->representation.string)
 300         return fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 301                          gfc_get_int_type (expr->ts.kind),
 302                          gfc_build_string_const (expr->representation.length,
 303                                                  expr->representation.string));
 304       else
 305         return gfc_conv_mpz_to_tree (expr->value.integer, expr->ts.kind);
 306
 307     case BT_REAL:
 308       if (expr->representation.string)
 309         return fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 310                          gfc_get_real_type (expr->ts.kind),
 311                          gfc_build_string_const (expr->representation.length,
 312                                                  expr->representation.string));
 313       else
 314         return gfc_conv_mpfr_to_tree (expr->value.real, expr->ts.kind, expr->is_snan);
 315
 316     case BT_LOGICAL:
 317       if (expr->representation.string)
 318         {
 319           tree tmp = fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 320                         gfc_get_int_type (expr->ts.kind),
 321                         gfc_build_string_const (expr->representation.length,
 322                                                 expr->representation.string));
 323           if (!integer_zerop (tmp) && !integer_onep (tmp))
 324             gfc_warning ("Assigning value other than 0 or 1 to LOGICAL"
 325                          " has undefined result at %L", &expr->where);
 326           return fold_convert (gfc_get_logical_type (expr->ts.kind), tmp);
 327         }
 328       else
 329         return build_int_cst (gfc_get_logical_type (expr->ts.kind),
 330                               expr->value.logical);
 331
 332     case BT_COMPLEX:
 333       if (expr->representation.string)
 334         return fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 335                          gfc_get_complex_type (expr->ts.kind),
 336                          gfc_build_string_const (expr->representation.length,
 337                                                  expr->representation.string));
 338       else
 339         {
 340           tree real = gfc_conv_mpfr_to_tree (mpc_realref (expr->value.complex),
 341                                           expr->ts.kind, expr->is_snan);
 342           tree imag = gfc_conv_mpfr_to_tree (mpc_imagref (expr->value.complex),
 343                                           expr->ts.kind, expr->is_snan);
 344
 345           return build_complex (gfc_typenode_for_spec (&expr->ts),
 346                                 real, imag);
 347         }
 348
 349     case BT_CHARACTER:
 350       res = gfc_build_wide_string_const (expr->ts.kind,
 351                                          expr->value.character.length,
 352                                          expr->value.character.string);
 353       return res;
 354
 355     case BT_HOLLERITH:
 356       return gfc_build_string_const (expr->representation.length,
 357                                      expr->representation.string);
 358
 359     default:
 360       fatal_error ("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 }