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
  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 tree
  70 gfc_build_string_const (int length, const char *s)
  71 {
  72   tree str;
  73   tree len;
  74
  75   str = build_string (length, s);
  76   len = build_int_cst (NULL_TREE, length);
  77   TREE_TYPE (str) =
  78     build_array_type (gfc_character1_type_node,
  79                       build_range_type (gfc_charlen_type_node,
  80                                         integer_one_node, len));
  81   return str;
  82 }
  83
  84 /* Build a Fortran character constant from a zero-terminated string.
  85    There a two version of this function, one that translates the string
  86    and one that doesn't.  */
  87 tree
  88 gfc_build_cstring_const (const char *string)
  89 {
  90   return gfc_build_string_const (strlen (string) + 1, string);
  91 }
  92
  93 tree
  94 gfc_build_localized_cstring_const (const char *msgid)
  95 {
  96   const char *localized = _(msgid);
  97   return gfc_build_string_const (strlen (localized) + 1, localized);
  98 }
  99
 100
 101 /* Return a string constant with the given length.  Used for static
 102    initializers.  The constant will be padded or truncated to match
 103    length.  */
 104
 105 tree
 106 gfc_conv_string_init (tree length, gfc_expr * expr)
 107 {
 108   gfc_char_t *s;
 109   char *c;
 110   HOST_WIDE_INT len;
 111   int slen;
 112   tree str;
 113
 114   gcc_assert (expr->expr_type == EXPR_CONSTANT);
 115   gcc_assert (expr->ts.type == BT_CHARACTER && expr->ts.kind == 1);
 116   gcc_assert (INTEGER_CST_P (length));
 117   gcc_assert (TREE_INT_CST_HIGH (length) == 0);
 118
 119   len = TREE_INT_CST_LOW (length);
 120   slen = expr->value.character.length;
 121
 122   if (len > slen)
 123     {
 124       s = gfc_get_wide_string (len);
 125       memcpy (s, expr->value.character.string, slen * sizeof (gfc_char_t));
 126       gfc_wide_memset (&s[slen], ' ', len - slen);
 127
 128       /* FIXME -- currently ignore wide character strings; see assert
 129          above.  */
 130       c = gfc_widechar_to_char (s, len);
 131       gfc_free (s);
 132     }
 133   else
 134     c = gfc_widechar_to_char (expr->value.character.string,
 135                               expr->value.character.length);
 136
 137   str = gfc_build_string_const (len, c);
 138   gfc_free (c);
 139
 140   return str;
 141 }
 142
 143
 144 /* Create a tree node for the string length if it is constant.  */
 145
 146 void
 147 gfc_conv_const_charlen (gfc_charlen * cl)
 148 {
 149   if (cl->backend_decl)
 150     return;
 151
 152   if (cl->length && cl->length->expr_type == EXPR_CONSTANT)
 153     {
 154       cl->backend_decl = gfc_conv_mpz_to_tree (cl->length->value.integer,
 155                                                cl->length->ts.kind);
 156       cl->backend_decl = fold_convert (gfc_charlen_type_node,
 157                                         cl->backend_decl);
 158     }
 159 }
 160
 161 void
 162 gfc_init_constants (void)
 163 {
 164   int n;
 165
 166   for (n = 0; n <= GFC_MAX_DIMENSIONS; n++)
 167     gfc_rank_cst[n] = build_int_cst (gfc_array_index_type, n);
 168 }
 169
 170 /* Converts a GMP integer into a backend tree node.  */
 171
 172 tree
 173 gfc_conv_mpz_to_tree (mpz_t i, int kind)
 174 {
 175   double_int val = mpz_get_double_int (gfc_get_int_type (kind), i, true);
 176   return double_int_to_tree (gfc_get_int_type (kind), val);
 177 }
 178
 179 /* Converts a backend tree into a GMP integer.  */
 180
 181 void
 182 gfc_conv_tree_to_mpz (mpz_t i, tree source)
 183 {
 184   double_int val = tree_to_double_int (source);
 185   mpz_set_double_int (i, val, TYPE_UNSIGNED (TREE_TYPE (source)));
 186 }
 187
 188 /* Converts a real constant into backend form.  */
 189
 190 tree
 191 gfc_conv_mpfr_to_tree (mpfr_t f, int kind)
 192 {
 193   tree type;
 194   int n;
 195   REAL_VALUE_TYPE real;
 196
 197   n = gfc_validate_kind (BT_REAL, kind, false);
 198   gcc_assert (gfc_real_kinds[n].radix == 2);
 199
 200   type = gfc_get_real_type (kind);
 201   real_from_mpfr (&real, f, type, GFC_RND_MODE);
 202   return build_real (type, real);
 203 }
 204
 205 /* Converts a backend tree into a real constant.  */
 206
 207 void
 208 gfc_conv_tree_to_mpfr (mpfr_ptr f, tree source)
 209 {
 210   mpfr_from_real (f, TREE_REAL_CST_PTR (source), GFC_RND_MODE);
 211 }
 212
 213 /* Translate any literal constant to a tree.  Constants never have
 214    pre or post chains.  Character literal constants are special
 215    special because they have a value and a length, so they cannot be
 216    returned as a single tree.  It is up to the caller to set the
 217    length somewhere if necessary.
 218
 219    Returns the translated constant, or aborts if it gets a type it
 220    can't handle.  */
 221
 222 tree
 223 gfc_conv_constant_to_tree (gfc_expr * expr)
 224 {
 225   tree res;
 226   char *s;
 227
 228   gcc_assert (expr->expr_type == EXPR_CONSTANT);
 229
 230   /* If it is has a prescribed memory representation, we build a string
 231      constant and VIEW_CONVERT to its type.  */
 232
 233   switch (expr->ts.type)
 234     {
 235     case BT_INTEGER:
 236       if (expr->representation.string)
 237         return fold_build1 (VIEW_CONVERT_EXPR,
 238                             gfc_get_int_type (expr->ts.kind),
 239                             gfc_build_string_const (expr->representation.length,
 240                                                     expr->representation.string));
 241       else
 242         return gfc_conv_mpz_to_tree (expr->value.integer, expr->ts.kind);
 243
 244     case BT_REAL:
 245       if (expr->representation.string)
 246         return fold_build1 (VIEW_CONVERT_EXPR,
 247                             gfc_get_real_type (expr->ts.kind),
 248                             gfc_build_string_const (expr->representation.length,
 249                                                     expr->representation.string));
 250       else
 251         return gfc_conv_mpfr_to_tree (expr->value.real, expr->ts.kind);
 252
 253     case BT_LOGICAL:
 254       if (expr->representation.string)
 255         return fold_build1 (VIEW_CONVERT_EXPR,
 256                             gfc_get_logical_type (expr->ts.kind),
 257                             gfc_build_string_const (expr->representation.length,
 258                                                     expr->representation.string));
 259       else
 260         return build_int_cst (gfc_get_logical_type (expr->ts.kind),
 261                             expr->value.logical);
 262
 263     case BT_COMPLEX:
 264       if (expr->representation.string)
 265         return fold_build1 (VIEW_CONVERT_EXPR,
 266                             gfc_get_complex_type (expr->ts.kind),
 267                             gfc_build_string_const (expr->representation.length,
 268                                                     expr->representation.string));
 269       else
 270         {
 271           tree real = gfc_conv_mpfr_to_tree (expr->value.complex.r,
 272                                           expr->ts.kind);
 273           tree imag = gfc_conv_mpfr_to_tree (expr->value.complex.i,
 274                                           expr->ts.kind);
 275
 276           return build_complex (gfc_typenode_for_spec (&expr->ts),
 277                                 real, imag);
 278         }
 279
 280     case BT_CHARACTER:
 281       gcc_assert (expr->ts.kind == 1);
 282       s = gfc_widechar_to_char (expr->value.character.string,
 283                                 expr->value.character.length);
 284       res = gfc_build_string_const (expr->value.character.length, s);
 285       gfc_free (s);
 286       return res;
 287
 288     case BT_HOLLERITH:
 289       return gfc_build_string_const (expr->representation.length,
 290                                      expr->representation.string);
 291
 292     default:
 293       fatal_error ("gfc_conv_constant_to_tree(): invalid type: %s",
 294                    gfc_typename (&expr->ts));
 295     }
 296 }
 297
 298
 299 /* Like gfc_conv_constant_to_tree, but for a simplified expression.
 300    We can handle character literal constants here as well.  */
 301
 302 void
 303 gfc_conv_constant (gfc_se * se, gfc_expr * expr)
 304 {
 305   /* We may be receiving an expression for C_NULL_PTR or C_NULL_FUNPTR.  If
 306      so, they expr_type will not yet be an EXPR_CONSTANT.  We need to make
 307      it so here.  */
 308   if (expr->ts.type == BT_DERIVED && expr->ts.derived
 309       && expr->ts.derived->attr.is_iso_c)
 310     {
 311       if (expr->symtree->n.sym->intmod_sym_id == ISOCBINDING_NULL_PTR
 312           || expr->symtree->n.sym->intmod_sym_id == ISOCBINDING_NULL_FUNPTR)
 313         {
 314           /* Create a new EXPR_CONSTANT expression for our local uses.  */
 315           expr = gfc_int_expr (0);
 316         }
 317     }
 318
 319   gcc_assert (expr->expr_type == EXPR_CONSTANT);
 320
 321   if (se->ss != NULL)
 322     {
 323       gcc_assert (se->ss != gfc_ss_terminator);
 324       gcc_assert (se->ss->type == GFC_SS_SCALAR);
 325       gcc_assert (se->ss->expr == expr);
 326
 327       se->expr = se->ss->data.scalar.expr;
 328       se->string_length = se->ss->string_length;
 329       gfc_advance_se_ss_chain (se);
 330       return;
 331     }
 332
 333   /* Translate the constant and put it in the simplifier structure.  */
 334   se->expr = gfc_conv_constant_to_tree (expr);
 335
 336   /* If this is a CHARACTER string, set its length in the simplifier
 337      structure, too.  */
 338   if (expr->ts.type == BT_CHARACTER)
 339     se->string_length = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (se->expr)));
 340 }