gcc/fortran/trans-const.c

   1 /* Translation of constants
   2    Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
   3    Free Software Foundation, Inc.
   4    Contributed by Paul Brook
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 /* trans-const.c -- convert constant values */
  23
  24 #include "config.h"
  25 #include "system.h"
  26 #include "coretypes.h"
  27 #include "tree.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
  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   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, int 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   return str;
 113 }
 114
 115
 116 /* Build a Fortran character constant from a zero-terminated string.
 117    There a two version of this function, one that translates the string
 118    and one that doesn't.  */
 119 tree
 120 gfc_build_cstring_const (const char *string)
 121 {
 122   return gfc_build_string_const (strlen (string) + 1, string);
 123 }
 124
 125 tree
 126 gfc_build_localized_cstring_const (const char *msgid)
 127 {
 128   const char *localized = _(msgid);
 129   return gfc_build_string_const (strlen (localized) + 1, localized);
 130 }
 131
 132
 133 /* Return a string constant with the given length.  Used for static
 134    initializers.  The constant will be padded or truncated to match
 135    length.  */
 136
 137 tree
 138 gfc_conv_string_init (tree length, gfc_expr * expr)
 139 {
 140   gfc_char_t *s;
 141   HOST_WIDE_INT len;
 142   int slen;
 143   tree str;
 144   bool free_s = false;
 145
 146   gcc_assert (expr->expr_type == EXPR_CONSTANT);
 147   gcc_assert (expr->ts.type == BT_CHARACTER);
 148   gcc_assert (INTEGER_CST_P (length));
 149   gcc_assert (TREE_INT_CST_HIGH (length) == 0);
 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   double_int val = mpz_get_double_int (gfc_get_int_type (kind), i, true);
 205   return double_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   double_int val = tree_to_double_int (source);
 214   mpz_set_double_int (i, val, TYPE_UNSIGNED (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 /* Converts a backend tree into a real constant.  */
 259
 260 void
 261 gfc_conv_tree_to_mpfr (mpfr_ptr f, tree source)
 262 {
 263   mpfr_from_real (f, TREE_REAL_CST_PTR (source), GFC_RND_MODE);
 264 }
 265
 266 /* Translate any literal constant to a tree.  Constants never have
 267    pre or post chains.  Character literal constants are special
 268    special because they have a value and a length, so they cannot be
 269    returned as a single tree.  It is up to the caller to set the
 270    length somewhere if necessary.
 271
 272    Returns the translated constant, or aborts if it gets a type it
 273    can't handle.  */
 274
 275 tree
 276 gfc_conv_constant_to_tree (gfc_expr * expr)
 277 {
 278   tree res;
 279
 280   gcc_assert (expr->expr_type == EXPR_CONSTANT);
 281
 282   /* If it is has a prescribed memory representation, we build a string
 283      constant and VIEW_CONVERT to its type.  */
 284
 285   switch (expr->ts.type)
 286     {
 287     case BT_INTEGER:
 288       if (expr->representation.string)
 289         return fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 290                          gfc_get_int_type (expr->ts.kind),
 291                          gfc_build_string_const (expr->representation.length,
 292                                                  expr->representation.string));
 293       else
 294         return gfc_conv_mpz_to_tree (expr->value.integer, expr->ts.kind);
 295
 296     case BT_REAL:
 297       if (expr->representation.string)
 298         return fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 299                          gfc_get_real_type (expr->ts.kind),
 300                          gfc_build_string_const (expr->representation.length,
 301                                                  expr->representation.string));
 302       else
 303         return gfc_conv_mpfr_to_tree (expr->value.real, expr->ts.kind, expr->is_snan);
 304
 305     case BT_LOGICAL:
 306       if (expr->representation.string)
 307         {
 308           tree tmp = fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 309                         gfc_get_int_type (expr->ts.kind),
 310                         gfc_build_string_const (expr->representation.length,
 311                                                 expr->representation.string));
 312           if (!integer_zerop (tmp) && !integer_onep (tmp))
 313             gfc_warning ("Assigning value other than 0 or 1 to LOGICAL"
 314                          " has undefined result at %L", &expr->where);
 315           return fold_convert (gfc_get_logical_type (expr->ts.kind), tmp);
 316         }
 317       else
 318         return build_int_cst (gfc_get_logical_type (expr->ts.kind),
 319                               expr->value.logical);
 320
 321     case BT_COMPLEX:
 322       if (expr->representation.string)
 323         return fold_build1_loc (input_location, VIEW_CONVERT_EXPR,
 324                          gfc_get_complex_type (expr->ts.kind),
 325                          gfc_build_string_const (expr->representation.length,
 326                                                  expr->representation.string));
 327       else
 328         {
 329           tree real = gfc_conv_mpfr_to_tree (mpc_realref (expr->value.complex),
 330                                           expr->ts.kind, expr->is_snan);
 331           tree imag = gfc_conv_mpfr_to_tree (mpc_imagref (expr->value.complex),
 332                                           expr->ts.kind, expr->is_snan);
 333
 334           return build_complex (gfc_typenode_for_spec (&expr->ts),
 335                                 real, imag);
 336         }
 337
 338     case BT_CHARACTER:
 339       res = gfc_build_wide_string_const (expr->ts.kind,
 340                                          expr->value.character.length,
 341                                          expr->value.character.string);
 342       return res;
 343
 344     case BT_HOLLERITH:
 345       return gfc_build_string_const (expr->representation.length,
 346                                      expr->representation.string);
 347
 348     default:
 349       fatal_error ("gfc_conv_constant_to_tree(): invalid type: %s",
 350                    gfc_typename (&expr->ts));
 351     }
 352 }
 353
 354
 355 /* Like gfc_conv_constant_to_tree, but for a simplified expression.
 356    We can handle character literal constants here as well.  */
 357
 358 void
 359 gfc_conv_constant (gfc_se * se, gfc_expr * expr)
 360 {
 361   gfc_ss *ss;
 362
 363   /* We may be receiving an expression for C_NULL_PTR or C_NULL_FUNPTR.  If
 364      so, the expr_type will not yet be an EXPR_CONSTANT.  We need to make
 365      it so here.  */
 366   if (expr->ts.type == BT_DERIVED && expr->ts.u.derived
 367       && expr->ts.u.derived->attr.is_iso_c)
 368     {
 369       if (expr->symtree->n.sym->intmod_sym_id == ISOCBINDING_NULL_PTR
 370           || expr->symtree->n.sym->intmod_sym_id == ISOCBINDING_NULL_FUNPTR)
 371         {
 372           /* Create a new EXPR_CONSTANT expression for our local uses.  */
 373           expr = gfc_get_int_expr (gfc_default_integer_kind, NULL, 0);
 374         }
 375     }
 376
 377   if (expr->expr_type != EXPR_CONSTANT)
 378     {
 379       gfc_expr *e = gfc_get_int_expr (gfc_default_integer_kind, NULL, 0);
 380       gfc_error ("non-constant initialization expression at %L", &expr->where);
 381       se->expr = gfc_conv_constant_to_tree (e);
 382       return;
 383     }
 384
 385   ss = se->ss;
 386   if (ss != NULL)
 387     {
 388       gfc_ss_info *ss_info;
 389
 390       ss_info = ss->info;
 391       gcc_assert (ss != gfc_ss_terminator);
 392       gcc_assert (ss_info->type == GFC_SS_SCALAR);
 393       gcc_assert (ss_info->expr == expr);
 394
 395       se->expr = se->ss->data.scalar.expr;
 396       se->string_length = se->ss->string_length;
 397       gfc_advance_se_ss_chain (se);
 398       return;
 399     }
 400
 401   /* Translate the constant and put it in the simplifier structure.  */
 402   se->expr = gfc_conv_constant_to_tree (expr);
 403
 404   /* If this is a CHARACTER string, set its length in the simplifier
 405      structure, too.  */
 406   if (expr->ts.type == BT_CHARACTER)
 407     se->string_length = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (se->expr)));
 408 }