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