gcc/fortran/trans-const.c

   1 /* Translation of constants
   2    Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007 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    Since this is mainly used for error messages, the string will get
  86    translated.  */
  87 tree
  88 gfc_build_cstring_const (const char *msgid)
  89 {
  90   return gfc_build_string_const (strlen (msgid) + 1, _(msgid));
  91 }
  92
  93 /* Return a string constant with the given length.  Used for static
  94    initializers.  The constant will be padded or truncated to match
  95    length.  */
  96
  97 tree
  98 gfc_conv_string_init (tree length, gfc_expr * expr)
  99 {
 100   char *s;
 101   HOST_WIDE_INT len;
 102   int slen;
 103   tree str;
 104
 105   gcc_assert (expr->expr_type == EXPR_CONSTANT);
 106   gcc_assert (expr->ts.type == BT_CHARACTER && expr->ts.kind == 1);
 107   gcc_assert (INTEGER_CST_P (length));
 108   gcc_assert (TREE_INT_CST_HIGH (length) == 0);
 109
 110   len = TREE_INT_CST_LOW (length);
 111   slen = expr->value.character.length;
 112
 113   if (len > slen)
 114     {
 115       s = gfc_getmem (len);
 116       memcpy (s, expr->value.character.string, slen);
 117       memset (&s[slen], ' ', len - slen);
 118       str = gfc_build_string_const (len, s);
 119       gfc_free (s);
 120     }
 121   else
 122     str = gfc_build_string_const (len, expr->value.character.string);
 123
 124   return str;
 125 }
 126
 127
 128 /* Create a tree node for the string length if it is constant.  */
 129
 130 void
 131 gfc_conv_const_charlen (gfc_charlen * cl)
 132 {
 133   if (cl->backend_decl)
 134     return;
 135
 136   if (cl->length && cl->length->expr_type == EXPR_CONSTANT)
 137     {
 138       cl->backend_decl = gfc_conv_mpz_to_tree (cl->length->value.integer,
 139                                                cl->length->ts.kind);
 140       cl->backend_decl = fold_convert (gfc_charlen_type_node,
 141                                         cl->backend_decl);
 142     }
 143 }
 144
 145 void
 146 gfc_init_constants (void)
 147 {
 148   int n;
 149
 150   for (n = 0; n <= GFC_MAX_DIMENSIONS; n++)
 151     gfc_rank_cst[n] = build_int_cst (gfc_array_index_type, n);
 152 }
 153
 154 /* Converts a GMP integer into a backend tree node.  */
 155
 156 tree
 157 gfc_conv_mpz_to_tree (mpz_t i, int kind)
 158 {
 159   double_int val = mpz_get_double_int (gfc_get_int_type (kind), i, true);
 160   return double_int_to_tree (gfc_get_int_type (kind), val);
 161 }
 162
 163 /* Converts a backend tree into a GMP integer.  */
 164
 165 void
 166 gfc_conv_tree_to_mpz (mpz_t i, tree source)
 167 {
 168   double_int val = tree_to_double_int (source);
 169   mpz_set_double_int (i, val, TYPE_UNSIGNED (TREE_TYPE (source)));
 170 }
 171
 172 /* Converts a real constant into backend form.  */
 173
 174 tree
 175 gfc_conv_mpfr_to_tree (mpfr_t f, int kind)
 176 {
 177   tree type;
 178   int n;
 179   REAL_VALUE_TYPE real;
 180
 181   n = gfc_validate_kind (BT_REAL, kind, false);
 182   gcc_assert (gfc_real_kinds[n].radix == 2);
 183
 184   type = gfc_get_real_type (kind);
 185   real_from_mpfr (&real, f, type, GFC_RND_MODE);
 186   return build_real (type, real);
 187 }
 188
 189 /* Converts a backend tree into a real constant.  */
 190
 191 void
 192 gfc_conv_tree_to_mpfr (mpfr_ptr f, tree source)
 193 {
 194   mpfr_from_real (f, TREE_REAL_CST_PTR (source), GFC_RND_MODE);
 195 }
 196
 197 /* Translate any literal constant to a tree.  Constants never have
 198    pre or post chains.  Character literal constants are special
 199    special because they have a value and a length, so they cannot be
 200    returned as a single tree.  It is up to the caller to set the
 201    length somewhere if necessary.
 202
 203    Returns the translated constant, or aborts if it gets a type it
 204    can't handle.  */
 205
 206 tree
 207 gfc_conv_constant_to_tree (gfc_expr * expr)
 208 {
 209   gcc_assert (expr->expr_type == EXPR_CONSTANT);
 210
 211   /* If it is has a prescribed memory representation, we build a string
 212      constant and VIEW_CONVERT to its type.  */
 213
 214   switch (expr->ts.type)
 215     {
 216     case BT_INTEGER:
 217       if (expr->representation.string)
 218         return build1 (VIEW_CONVERT_EXPR,
 219                         gfc_get_int_type (expr->ts.kind),
 220                         gfc_build_string_const (expr->representation.length,
 221                                 expr->representation.string));
 222       else
 223         return gfc_conv_mpz_to_tree (expr->value.integer, expr->ts.kind);
 224
 225     case BT_REAL:
 226       if (expr->representation.string)
 227         return build1 (VIEW_CONVERT_EXPR,
 228                         gfc_get_real_type (expr->ts.kind),
 229                         gfc_build_string_const (expr->representation.length,
 230                                 expr->representation.string));
 231       else
 232         return gfc_conv_mpfr_to_tree (expr->value.real, expr->ts.kind);
 233
 234     case BT_LOGICAL:
 235       if (expr->representation.string)
 236         return build1 (VIEW_CONVERT_EXPR,
 237                         gfc_get_logical_type (expr->ts.kind),
 238                         gfc_build_string_const (expr->representation.length,
 239                                 expr->representation.string));
 240       else
 241         return build_int_cst (gfc_get_logical_type (expr->ts.kind),
 242                             expr->value.logical);
 243
 244     case BT_COMPLEX:
 245       if (expr->representation.string)
 246         return build1 (VIEW_CONVERT_EXPR,
 247                         gfc_get_complex_type (expr->ts.kind),
 248                         gfc_build_string_const (expr->representation.length,
 249                                 expr->representation.string));
 250       else
 251         {
 252           tree real = gfc_conv_mpfr_to_tree (expr->value.complex.r,
 253                                           expr->ts.kind);
 254           tree imag = gfc_conv_mpfr_to_tree (expr->value.complex.i,
 255                                           expr->ts.kind);
 256
 257           return build_complex (gfc_typenode_for_spec (&expr->ts),
 258                                 real, imag);
 259         }
 260
 261     case BT_CHARACTER:
 262       return gfc_build_string_const (expr->value.character.length,
 263                                      expr->value.character.string);
 264
 265     case BT_HOLLERITH:
 266       return gfc_build_string_const (expr->representation.length,
 267                                      expr->representation.string);
 268
 269     default:
 270       fatal_error ("gfc_conv_constant_to_tree(): invalid type: %s",
 271                    gfc_typename (&expr->ts));
 272     }
 273 }
 274
 275
 276 /* Like gfc_conv_constant_to_tree, but for a simplified expression.
 277    We can handle character literal constants here as well.  */
 278
 279 void
 280 gfc_conv_constant (gfc_se * se, gfc_expr * expr)
 281 {
 282   /* We may be receiving an expression for C_NULL_PTR or C_NULL_FUNPTR.  If
 283      so, they expr_type will not yet be an EXPR_CONSTANT.  We need to make
 284      it so here.  */
 285   if (expr->ts.type == BT_DERIVED && expr->ts.derived
 286       && expr->ts.derived->attr.is_iso_c)
 287     {
 288       if (expr->symtree->n.sym->intmod_sym_id == ISOCBINDING_NULL_PTR
 289           || expr->symtree->n.sym->intmod_sym_id == ISOCBINDING_NULL_FUNPTR)
 290         {
 291           /* Create a new EXPR_CONSTANT expression for our local uses.  */
 292           expr = gfc_int_expr (0);
 293         }
 294     }
 295
 296   gcc_assert (expr->expr_type == EXPR_CONSTANT);
 297
 298   if (se->ss != NULL)
 299     {
 300       gcc_assert (se->ss != gfc_ss_terminator);
 301       gcc_assert (se->ss->type == GFC_SS_SCALAR);
 302       gcc_assert (se->ss->expr == expr);
 303
 304       se->expr = se->ss->data.scalar.expr;
 305       se->string_length = se->ss->string_length;
 306       gfc_advance_se_ss_chain (se);
 307       return;
 308     }
 309
 310   /* Translate the constant and put it in the simplifier structure.  */
 311   se->expr = gfc_conv_constant_to_tree (expr);
 312
 313   /* If this is a CHARACTER string, set its length in the simplifier
 314      structure, too.  */
 315   if (expr->ts.type == BT_CHARACTER)
 316     se->string_length = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (se->expr)));
 317 }