gcc/fortran/trans-const.c

   1 /* Translation of constants
   2    Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software
   3    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 "ggc.h"
  29 #include "toplev.h"
  30 #include "real.h"
  31 #include "double-int.h"
  32 #include "gfortran.h"
  33 #include "trans.h"
  34 #include "trans-const.h"
  35 #include "trans-types.h"
  36 #include "target-memory.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 = build_int_cst (NULL_TREE, length);
  80   TREE_TYPE (str) =
  81     build_array_type (gfc_character1_type_node,
  82                       build_range_type (gfc_charlen_type_node,
  83                                         integer_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 = gfc_getmem (size);
 103   gfc_encode_character (kind, length, string, (unsigned char *) s, size);
 104
 105   str = build_string (size, s);
 106   gfc_free (s);
 107
 108   len = build_int_cst (NULL_TREE, length);
 109   TREE_TYPE (str) =
 110     build_array_type (gfc_get_char_type (kind),
 111                       build_range_type (gfc_charlen_type_node,
 112                                         integer_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 (INTEGER_CST_P (length));
 150   gcc_assert (TREE_INT_CST_HIGH (length) == 0);
 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     gfc_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->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   double_int val = mpz_get_double_int (gfc_get_int_type (kind), i, true);
 206   return double_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   double_int val = tree_to_double_int (source);
 215   mpz_set_double_int (i, val, TYPE_UNSIGNED (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)
 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   real_from_mpfr (&real, f, type, GFC_RND_MODE);
 232   return build_real (type, real);
 233 }
 234
 235 /* Converts a backend tree into a real constant.  */
 236
 237 void
 238 gfc_conv_tree_to_mpfr (mpfr_ptr f, tree source)
 239 {
 240   mpfr_from_real (f, TREE_REAL_CST_PTR (source), GFC_RND_MODE);
 241 }
 242
 243 /* Translate any literal constant to a tree.  Constants never have
 244    pre or post chains.  Character literal constants are special
 245    special because they have a value and a length, so they cannot be
 246    returned as a single tree.  It is up to the caller to set the
 247    length somewhere if necessary.
 248
 249    Returns the translated constant, or aborts if it gets a type it
 250    can't handle.  */
 251
 252 tree
 253 gfc_conv_constant_to_tree (gfc_expr * expr)
 254 {
 255   tree res;
 256
 257   gcc_assert (expr->expr_type == EXPR_CONSTANT);
 258
 259   /* If it is has a prescribed memory representation, we build a string
 260      constant and VIEW_CONVERT to its type.  */
 261
 262   switch (expr->ts.type)
 263     {
 264     case BT_INTEGER:
 265       if (expr->representation.string)
 266         return fold_build1 (VIEW_CONVERT_EXPR,
 267                             gfc_get_int_type (expr->ts.kind),
 268                             gfc_build_string_const (expr->representation.length,
 269                                                     expr->representation.string));
 270       else
 271         return gfc_conv_mpz_to_tree (expr->value.integer, expr->ts.kind);
 272
 273     case BT_REAL:
 274       if (expr->representation.string)
 275         return fold_build1 (VIEW_CONVERT_EXPR,
 276                             gfc_get_real_type (expr->ts.kind),
 277                             gfc_build_string_const (expr->representation.length,
 278                                                     expr->representation.string));
 279       else
 280         return gfc_conv_mpfr_to_tree (expr->value.real, expr->ts.kind);
 281
 282     case BT_LOGICAL:
 283       if (expr->representation.string)
 284         return fold_build1 (VIEW_CONVERT_EXPR,
 285                             gfc_get_logical_type (expr->ts.kind),
 286                             gfc_build_string_const (expr->representation.length,
 287                                                     expr->representation.string));
 288       else
 289         return build_int_cst (gfc_get_logical_type (expr->ts.kind),
 290                             expr->value.logical);
 291
 292     case BT_COMPLEX:
 293       if (expr->representation.string)
 294         return fold_build1 (VIEW_CONVERT_EXPR,
 295                             gfc_get_complex_type (expr->ts.kind),
 296                             gfc_build_string_const (expr->representation.length,
 297                                                     expr->representation.string));
 298       else
 299         {
 300           tree real = gfc_conv_mpfr_to_tree (expr->value.complex.r,
 301                                           expr->ts.kind);
 302           tree imag = gfc_conv_mpfr_to_tree (expr->value.complex.i,
 303                                           expr->ts.kind);
 304
 305           return build_complex (gfc_typenode_for_spec (&expr->ts),
 306                                 real, imag);
 307         }
 308
 309     case BT_CHARACTER:
 310       res = gfc_build_wide_string_const (expr->ts.kind,
 311                                          expr->value.character.length,
 312                                          expr->value.character.string);
 313       return res;
 314
 315     case BT_HOLLERITH:
 316       return gfc_build_string_const (expr->representation.length,
 317                                      expr->representation.string);
 318
 319     default:
 320       fatal_error ("gfc_conv_constant_to_tree(): invalid type: %s",
 321                    gfc_typename (&expr->ts));
 322     }
 323 }
 324
 325
 326 /* Like gfc_conv_constant_to_tree, but for a simplified expression.
 327    We can handle character literal constants here as well.  */
 328
 329 void
 330 gfc_conv_constant (gfc_se * se, gfc_expr * expr)
 331 {
 332   /* We may be receiving an expression for C_NULL_PTR or C_NULL_FUNPTR.  If
 333      so, they expr_type will not yet be an EXPR_CONSTANT.  We need to make
 334      it so here.  */
 335   if (expr->ts.type == BT_DERIVED && expr->ts.derived
 336       && expr->ts.derived->attr.is_iso_c)
 337     {
 338       if (expr->symtree->n.sym->intmod_sym_id == ISOCBINDING_NULL_PTR
 339           || expr->symtree->n.sym->intmod_sym_id == ISOCBINDING_NULL_FUNPTR)
 340         {
 341           /* Create a new EXPR_CONSTANT expression for our local uses.  */
 342           expr = gfc_int_expr (0);
 343         }
 344     }
 345
 346   gcc_assert (expr->expr_type == EXPR_CONSTANT);
 347
 348   if (se->ss != NULL)
 349     {
 350       gcc_assert (se->ss != gfc_ss_terminator);
 351       gcc_assert (se->ss->type == GFC_SS_SCALAR);
 352       gcc_assert (se->ss->expr == expr);
 353
 354       se->expr = se->ss->data.scalar.expr;
 355       se->string_length = se->ss->string_length;
 356       gfc_advance_se_ss_chain (se);
 357       return;
 358     }
 359
 360   /* Translate the constant and put it in the simplifier structure.  */
 361   se->expr = gfc_conv_constant_to_tree (expr);
 362
 363   /* If this is a CHARACTER string, set its length in the simplifier
 364      structure, too.  */
 365   if (expr->ts.type == BT_CHARACTER)
 366     se->string_length = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (se->expr)));
 367 }