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/* Translation of constants

   Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software

   Foundation, Inc.

   Contributed by Paul Brook

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under

the terms of the GNU General Public License as published by the Free

Software Foundation; either version 3, or (at your option) any later

version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY

WARRANTY; without even the implied warranty of MERCHANTABILITY or

FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

for more details.

You should have received a copy of the GNU General Public License

along with GCC; see the file COPYING3.  If not see

<http://www.gnu.org/licenses/>.  */

/* trans-const.c -- convert constant values */

#include "config.h"

#include "system.h"

#include "coretypes.h"

#include "tree.h"

#include "ggc.h"

#include "toplev.h"

#include "real.h"

#include "double-int.h"

#include "gfortran.h"

#include "trans.h"

#include "trans-const.h"

#include "trans-types.h"

#include "target-memory.h"

tree gfc_rank_cst[GFC_MAX_DIMENSIONS + 1];

/* Build a constant with given type from an int_cst.  */

tree

gfc_build_const (tree type, tree intval)

{

  tree val;

  tree zero;

  switch (TREE_CODE (type))

    {

    case INTEGER_TYPE:

      val = convert (type, intval);

      break;

    case REAL_TYPE:

      val = build_real_from_int_cst (type, intval);

      break;

    case COMPLEX_TYPE:

      val = build_real_from_int_cst (TREE_TYPE (type), intval);

      zero = build_real_from_int_cst (TREE_TYPE (type), integer_zero_node);

      val = build_complex (type, val, zero);

      break;

    default:

      gcc_unreachable ();

    }

  return val;

}

/* Build a string constant with C char type.  */

tree

gfc_build_string_const (int length, const char *s)

{

  tree str;

  tree len;

  str = build_string (length, s);

  len = build_int_cst (NULL_TREE, length);

  TREE_TYPE (str) =

    build_array_type (gfc_character1_type_node,

                      build_range_type (gfc_charlen_type_node,

                                        integer_one_node, len));

  return str;

}

/* Build a string constant with a type given by its kind; take care of

   non-default character kinds.  */

tree

gfc_build_wide_string_const (int kind, int length, const gfc_char_t *string)

{

  int i;

  tree str, len;

  size_t size;

  char *s;

  i = gfc_validate_kind (BT_CHARACTER, kind, false);

  size = length * gfc_character_kinds[i].bit_size / 8;

  s = XCNEWVAR (char, size);

  gfc_encode_character (kind, length, string, (unsigned char *) s, size);

  str = build_string (size, s);

  gfc_free (s);

  len = build_int_cst (NULL_TREE, length);

  TREE_TYPE (str) =

    build_array_type (gfc_get_char_type (kind),

                      build_range_type (gfc_charlen_type_node,

                                        integer_one_node, len));

  return str;

}

/* Build a Fortran character constant from a zero-terminated string.

   There a two version of this function, one that translates the string

   and one that doesn't.  */

tree

gfc_build_cstring_const (const char *string)

{

  return gfc_build_string_const (strlen (string) + 1, string);

}

tree

gfc_build_localized_cstring_const (const char *msgid)

{

  const char *localized = _(msgid);

  return gfc_build_string_const (strlen (localized) + 1, localized);

}

/* Return a string constant with the given length.  Used for static

   initializers.  The constant will be padded or truncated to match

   length.  */

tree

gfc_conv_string_init (tree length, gfc_expr * expr)

{

  gfc_char_t *s;

  HOST_WIDE_INT len;

  int slen;

  tree str;

  bool free_s = false;

  gcc_assert (expr->expr_type == EXPR_CONSTANT);

  gcc_assert (expr->ts.type == BT_CHARACTER);

  gcc_assert (INTEGER_CST_P (length));

  gcc_assert (TREE_INT_CST_HIGH (length) == 0);

  len = TREE_INT_CST_LOW (length);

  slen = expr->value.character.length;

  if (len > slen)

    {

      s = gfc_get_wide_string (len);

      memcpy (s, expr->value.character.string, slen * sizeof (gfc_char_t));

      gfc_wide_memset (&s[slen], ' ', len - slen);

      free_s = true;

    }

  else

    s = expr->value.character.string;

  str = gfc_build_wide_string_const (expr->ts.kind, len, s);

  if (free_s)

    gfc_free (s);

  return str;

}

/* Create a tree node for the string length if it is constant.  */

void

gfc_conv_const_charlen (gfc_charlen * cl)

{

  if (!cl || cl->backend_decl)

    return;

  if (cl->length && cl->length->expr_type == EXPR_CONSTANT)

    {

      cl->backend_decl = gfc_conv_mpz_to_tree (cl->length->value.integer,

                                               cl->length->ts.kind);

      cl->backend_decl = fold_convert (gfc_charlen_type_node,

                                        cl->backend_decl);

    }

}

void

gfc_init_constants (void)

{

  int n;

  for (n = 0; n <= GFC_MAX_DIMENSIONS; n++)

    gfc_rank_cst[n] = build_int_cst (gfc_array_index_type, n);

}

/* Converts a GMP integer into a backend tree node.  */

tree

gfc_conv_mpz_to_tree (mpz_t i, int kind)

{

  double_int val = mpz_get_double_int (gfc_get_int_type (kind), i, true);

  return double_int_to_tree (gfc_get_int_type (kind), val);

}

/* Converts a backend tree into a GMP integer.  */

void

gfc_conv_tree_to_mpz (mpz_t i, tree source)

{

  double_int val = tree_to_double_int (source);

  mpz_set_double_int (i, val, TYPE_UNSIGNED (TREE_TYPE (source)));

}

/* Converts a real constant into backend form.  */

tree

gfc_conv_mpfr_to_tree (mpfr_t f, int kind, int is_snan)

{

  tree type;

  int n;

  REAL_VALUE_TYPE real;

  n = gfc_validate_kind (BT_REAL, kind, false);

  gcc_assert (gfc_real_kinds[n].radix == 2);

  type = gfc_get_real_type (kind);

  if (mpfr_nan_p (f) && is_snan)

     real_from_string (&real, "SNaN");

  else

    real_from_mpfr (&real, f, type, GFC_RND_MODE);

  return build_real (type, real);

}

/* Converts a backend tree into a real constant.  */

void

gfc_conv_tree_to_mpfr (mpfr_ptr f, tree source)

{

  mpfr_from_real (f, TREE_REAL_CST_PTR (source), GFC_RND_MODE);

}

/* Translate any literal constant to a tree.  Constants never have

   pre or post chains.  Character literal constants are special

   special because they have a value and a length, so they cannot be

   returned as a single tree.  It is up to the caller to set the

   length somewhere if necessary.

   Returns the translated constant, or aborts if it gets a type it

   can't handle.  */

tree

gfc_conv_constant_to_tree (gfc_expr * expr)

{

  tree res;

  gcc_assert (expr->expr_type == EXPR_CONSTANT);

  /* If it is has a prescribed memory representation, we build a string

     constant and VIEW_CONVERT to its type.  */

  switch (expr->ts.type)

    {

    case BT_INTEGER:

      if (expr->representation.string)

        return fold_build1 (VIEW_CONVERT_EXPR,

                            gfc_get_int_type (expr->ts.kind),

                            gfc_build_string_const (expr->representation.length,

                                                    expr->representation.string));

      else

        return gfc_conv_mpz_to_tree (expr->value.integer, expr->ts.kind);

    case BT_REAL:

      if (expr->representation.string)

        return fold_build1 (VIEW_CONVERT_EXPR,

                            gfc_get_real_type (expr->ts.kind),

                            gfc_build_string_const (expr->representation.length,

                                                    expr->representation.string));

      else

        return gfc_conv_mpfr_to_tree (expr->value.real, expr->ts.kind, expr->is_snan);

    case BT_LOGICAL:

      if (expr->representation.string)

        {

          tree tmp = fold_build1 (VIEW_CONVERT_EXPR,

                                  gfc_get_int_type (expr->ts.kind),

                                  gfc_build_string_const (expr->representation.length,

                                                          expr->representation.string));

          if (!integer_zerop (tmp) && !integer_onep (tmp))

            gfc_warning ("Assigning value other than 0 or 1 to LOGICAL"

                         " has undefined result at %L", &expr->where);

          return fold_convert (gfc_get_logical_type (expr->ts.kind), tmp);

        }

      else

        return build_int_cst (gfc_get_logical_type (expr->ts.kind),

                              expr->value.logical);

    case BT_COMPLEX:

      if (expr->representation.string)

        return fold_build1 (VIEW_CONVERT_EXPR,

                            gfc_get_complex_type (expr->ts.kind),

                            gfc_build_string_const (expr->representation.length,

                                                    expr->representation.string));

      else

        {

          tree real = gfc_conv_mpfr_to_tree (mpc_realref (expr->value.complex),

                                          expr->ts.kind, expr->is_snan);

          tree imag = gfc_conv_mpfr_to_tree (mpc_imagref (expr->value.complex),

                                          expr->ts.kind, expr->is_snan);

          return build_complex (gfc_typenode_for_spec (&expr->ts),

                                real, imag);

        }

    case BT_CHARACTER:

      res = gfc_build_wide_string_const (expr->ts.kind,

                                         expr->value.character.length,

                                         expr->value.character.string);

      return res;

    case BT_HOLLERITH:

      return gfc_build_string_const (expr->representation.length,

                                     expr->representation.string);

    default:

      fatal_error ("gfc_conv_constant_to_tree(): invalid type: %s",

                   gfc_typename (&expr->ts));

    }

}

/* Like gfc_conv_constant_to_tree, but for a simplified expression.

   We can handle character literal constants here as well.  */

void

gfc_conv_constant (gfc_se * se, gfc_expr * expr)

{

  /* We may be receiving an expression for C_NULL_PTR or C_NULL_FUNPTR.  If

     so, the expr_type will not yet be an EXPR_CONSTANT.  We need to make

     it so here.  */

  if (expr->ts.type == BT_DERIVED && expr->ts.u.derived

      && expr->ts.u.derived->attr.is_iso_c)

    {

      if (expr->symtree->n.sym->intmod_sym_id == ISOCBINDING_NULL_PTR

          || expr->symtree->n.sym->intmod_sym_id == ISOCBINDING_NULL_FUNPTR)

        {

          /* Create a new EXPR_CONSTANT expression for our local uses.  */

          expr = gfc_int_expr (0);

        }

    }

  if (expr->expr_type != EXPR_CONSTANT)

    {

      gfc_error ("non-constant initialization expression at %L", &expr->where);

      se->expr = gfc_conv_constant_to_tree (gfc_int_expr (0));

      return;

    }

  if (se->ss != NULL)

    {

      gcc_assert (se->ss != gfc_ss_terminator);

      gcc_assert (se->ss->type == GFC_SS_SCALAR);

      gcc_assert (se->ss->expr == expr);

      se->expr = se->ss->data.scalar.expr;

      se->string_length = se->ss->string_length;

      gfc_advance_se_ss_chain (se);

      return;

    }

  /* Translate the constant and put it in the simplifier structure.  */

  se->expr = gfc_conv_constant_to_tree (expr);

  /* If this is a CHARACTER string, set its length in the simplifier

     structure, too.  */

  if (expr->ts.type == BT_CHARACTER)

    se->string_length = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (se->expr)));

}