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/* Supporting functions for resolving DATA statement.

   Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009

   Free Software Foundation, Inc.

   Contributed by Lifang Zeng <zlf605@hotmail.com>

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/>.  */

/* Notes for DATA statement implementation:

   We first assign initial value to each symbol by gfc_assign_data_value

   during resolving DATA statement. Refer to check_data_variable and

   traverse_data_list in resolve.c.

   The complexity exists in the handling of array section, implied do

   and array of struct appeared in DATA statement.

   We call gfc_conv_structure, gfc_con_array_array_initializer,

   etc., to convert the initial value. Refer to trans-expr.c and

   trans-array.c.  */

#include "config.h"

#include "gfortran.h"

#include "data.h"

static void formalize_init_expr (gfc_expr *);

/* Calculate the array element offset.  */

static void

get_array_index (gfc_array_ref *ar, mpz_t *offset)

{

  gfc_expr *e;

  int i;

  mpz_t delta;

  mpz_t tmp;

  mpz_init (tmp);

  mpz_set_si (*offset, 0);

  mpz_init_set_si (delta, 1);

  for (i = 0; i < ar->dimen; i++)

    {

      e = gfc_copy_expr (ar->start[i]);

      gfc_simplify_expr (e, 1);

      if ((gfc_is_constant_expr (ar->as->lower[i]) == 0)

          || (gfc_is_constant_expr (ar->as->upper[i]) == 0)

          || (gfc_is_constant_expr (e) == 0))

        gfc_error ("non-constant array in DATA statement %L", &ar->where);

      mpz_set (tmp, e->value.integer);

      mpz_sub (tmp, tmp, ar->as->lower[i]->value.integer);

      mpz_mul (tmp, tmp, delta);

      mpz_add (*offset, tmp, *offset);

      mpz_sub (tmp, ar->as->upper[i]->value.integer,

               ar->as->lower[i]->value.integer);

      mpz_add_ui (tmp, tmp, 1);

      mpz_mul (delta, tmp, delta);

    }

  mpz_clear (delta);

  mpz_clear (tmp);

}

/* Find if there is a constructor which offset is equal to OFFSET.  */

static gfc_constructor *

find_con_by_offset (splay_tree spt, mpz_t offset)

{

  mpz_t tmp;

  gfc_constructor *ret = NULL;

  gfc_constructor *con;

  splay_tree_node sptn;

  /* The complexity is due to needing quick access to the linked list of

     constructors.  Both a linked list and a splay tree are used, and both

     are kept up to date if they are array elements (which is the only time

     that a specific constructor has to be found).  */

  gcc_assert (spt != NULL);

  mpz_init (tmp);

  sptn = splay_tree_lookup (spt, (splay_tree_key) mpz_get_si (offset));

  if (sptn)

    ret = (gfc_constructor*) sptn->value;

  else

    {

       /* Need to check and see if we match a range, so we will pull

          the next lowest index and see if the range matches.  */

       sptn = splay_tree_predecessor (spt,

                                      (splay_tree_key) mpz_get_si (offset));

       if (sptn)

         {

            con = (gfc_constructor*) sptn->value;

            if (mpz_cmp_ui (con->repeat, 1) > 0)

              {

                 mpz_init (tmp);

                 mpz_add (tmp, con->n.offset, con->repeat);

                 if (mpz_cmp (offset, tmp) < 0)

                   ret = con;

                 mpz_clear (tmp);

              }

            else

              ret = NULL; /* The range did not match.  */

         }

      else

        ret = NULL; /* No pred, so no match.  */

    }

  return ret;

}

/* Find if there is a constructor which component is equal to COM.  */

static gfc_constructor *

find_con_by_component (gfc_component *com, gfc_constructor *con)

{

  for (; con; con = con->next)

    {

      if (com == con->n.component)

        return con;

    }

  return NULL;

}

/* Create a character type initialization expression from RVALUE.

   TS [and REF] describe [the substring of] the variable being initialized.

   INIT is the existing initializer, not NULL.  Initialization is performed

   according to normal assignment rules.  */

static gfc_expr *

create_character_intializer (gfc_expr *init, gfc_typespec *ts,

                             gfc_ref *ref, gfc_expr *rvalue)

{

  int len, start, end;

  gfc_char_t *dest;

  gfc_extract_int (ts->u.cl->length, &len);

  if (init == NULL)

    {

      /* Create a new initializer.  */

      init = gfc_get_expr ();

      init->expr_type = EXPR_CONSTANT;

      init->ts = *ts;

      dest = gfc_get_wide_string (len + 1);

      dest[len] = '\0';

      init->value.character.length = len;

      init->value.character.string = dest;

      /* Blank the string if we're only setting a substring.  */

      if (ref != NULL)

        gfc_wide_memset (dest, ' ', len);

    }

  else

    dest = init->value.character.string;

  if (ref)

    {

      gfc_expr *start_expr, *end_expr;

      gcc_assert (ref->type == REF_SUBSTRING);

      /* Only set a substring of the destination.  Fortran substring bounds

         are one-based [start, end], we want zero based [start, end).  */

      start_expr = gfc_copy_expr (ref->u.ss.start);

      end_expr = gfc_copy_expr (ref->u.ss.end);

      if ((gfc_simplify_expr (start_expr, 1) == FAILURE)

          || (gfc_simplify_expr (end_expr, 1)) == FAILURE)

        {

          gfc_error ("failure to simplify substring reference in DATA "

                     "statement at %L", &ref->u.ss.start->where);

          return NULL;

        }

      gfc_extract_int (start_expr, &start);

      start--;

      gfc_extract_int (end_expr, &end);

    }

  else

    {

      /* Set the whole string.  */

      start = 0;

      end = len;

    }

  /* Copy the initial value.  */

  if (rvalue->ts.type == BT_HOLLERITH)

    len = rvalue->representation.length;

  else

    len = rvalue->value.character.length;

  if (len > end - start)

    {

      len = end - start;

      gfc_warning_now ("initialization string truncated to match variable "

                       "at %L", &rvalue->where);

    }

  if (rvalue->ts.type == BT_HOLLERITH)

    {

      int i;

      for (i = 0; i < len; i++)

        dest[start+i] = rvalue->representation.string[i];

    }

  else

    memcpy (&dest[start], rvalue->value.character.string,

            len * sizeof (gfc_char_t));

  /* Pad with spaces.  Substrings will already be blanked.  */

  if (len < end - start && ref == NULL)

    gfc_wide_memset (&dest[start + len], ' ', end - (start + len));

  if (rvalue->ts.type == BT_HOLLERITH)

    {

      init->representation.length = init->value.character.length;

      init->representation.string

        = gfc_widechar_to_char (init->value.character.string,

                                init->value.character.length);

    }

  return init;

}

/* Assign the initial value RVALUE to  LVALUE's symbol->value. If the

   LVALUE already has an initialization, we extend this, otherwise we

   create a new one.  */

gfc_try

gfc_assign_data_value (gfc_expr *lvalue, gfc_expr *rvalue, mpz_t index)

{

  gfc_ref *ref;

  gfc_expr *init;

  gfc_expr *expr;

  gfc_constructor *con;

  gfc_constructor *last_con;

  gfc_constructor *pred;

  gfc_symbol *symbol;

  gfc_typespec *last_ts;

  mpz_t offset;

  splay_tree spt;

  splay_tree_node sptn;

  symbol = lvalue->symtree->n.sym;

  init = symbol->value;

  last_ts = &symbol->ts;

  last_con = NULL;

  mpz_init_set_si (offset, 0);

  /* Find/create the parent expressions for subobject references.  */

  for (ref = lvalue->ref; ref; ref = ref->next)

    {

      /* Break out of the loop if we find a substring.  */

      if (ref->type == REF_SUBSTRING)

        {

          /* A substring should always be the last subobject reference.  */

          gcc_assert (ref->next == NULL);

          break;

        }

      /* Use the existing initializer expression if it exists.  Otherwise

         create a new one.  */

      if (init == NULL)

        expr = gfc_get_expr ();

      else

        expr = init;

      /* Find or create this element.  */

      switch (ref->type)

        {

        case REF_ARRAY:

          if (init && expr->expr_type != EXPR_ARRAY)

            {

              gfc_error ("'%s' at %L already is initialized at %L",

                         lvalue->symtree->n.sym->name, &lvalue->where,

                         &init->where);

              return FAILURE;

            }

          if (init == NULL)

            {

              /* The element typespec will be the same as the array

                 typespec.  */

              expr->ts = *last_ts;

              /* Setup the expression to hold the constructor.  */

              expr->expr_type = EXPR_ARRAY;

              expr->rank = ref->u.ar.as->rank;

            }

          if (ref->u.ar.type == AR_ELEMENT)

            get_array_index (&ref->u.ar, &offset);

          else

            mpz_set (offset, index);

          /* Check the bounds.  */

          if (mpz_cmp_si (offset, 0) < 0)

            {

              gfc_error ("Data element below array lower bound at %L",

                         &lvalue->where);

              return FAILURE;

            }

          else

            {

              mpz_t size;

              if (spec_size (ref->u.ar.as, &size) == SUCCESS)

                {

                  if (mpz_cmp (offset, size) >= 0)

                  {

                    mpz_clear (size);

                    gfc_error ("Data element above array upper bound at %L",

                               &lvalue->where);

                    return FAILURE;

                  }

                  mpz_clear (size);

                }

            }

          /* Splay tree containing offset and gfc_constructor.  */

          spt = expr->con_by_offset;

          if (spt == NULL)

            {

               spt = splay_tree_new (splay_tree_compare_ints, NULL, NULL);

               expr->con_by_offset = spt;

               con = NULL;

            }

         else

          con = find_con_by_offset (spt, offset);

          if (con == NULL)

            {

              splay_tree_key j;

              /* Create a new constructor.  */

              con = gfc_get_constructor ();

              mpz_set (con->n.offset, offset);

              j = (splay_tree_key) mpz_get_si (offset);

              sptn = splay_tree_insert (spt, j, (splay_tree_value) con);

              /* Fix up the linked list.  */

              sptn = splay_tree_predecessor (spt, j);

              if (sptn == NULL)

                {  /* Insert at the head.  */

                   con->next = expr->value.constructor;

                   expr->value.constructor = con;

                }

              else

                {  /* Insert in the chain.  */

                   pred = (gfc_constructor*) sptn->value;

                   con->next = pred->next;

                   pred->next = con;

                }

            }

          break;

        case REF_COMPONENT:

          if (init == NULL)

            {

              /* Setup the expression to hold the constructor.  */

              expr->expr_type = EXPR_STRUCTURE;

              expr->ts.type = BT_DERIVED;

              expr->ts.u.derived = ref->u.c.sym;

            }

          else

            gcc_assert (expr->expr_type == EXPR_STRUCTURE);

          last_ts = &ref->u.c.component->ts;

          /* Find the same element in the existing constructor.  */

          con = expr->value.constructor;

          con = find_con_by_component (ref->u.c.component, con);

          if (con == NULL)

            {

              /* Create a new constructor.  */

              con = gfc_get_constructor ();

              con->n.component = ref->u.c.component;

              con->next = expr->value.constructor;

              expr->value.constructor = con;

            }

          break;

        default:

          gcc_unreachable ();

        }

      if (init == NULL)

        {

          /* Point the container at the new expression.  */

          if (last_con == NULL)

            symbol->value = expr;

          else

            last_con->expr = expr;

        }

      init = con->expr;

      last_con = con;

    }

  if (ref || last_ts->type == BT_CHARACTER)

    {

      if (lvalue->ts.u.cl->length == NULL && !(ref && ref->u.ss.length != NULL))

        return FAILURE;

      expr = create_character_intializer (init, last_ts, ref, rvalue);

    }

  else

    {

      /* Overwriting an existing initializer is non-standard but usually only

         provokes a warning from other compilers.  */

      if (init != NULL)

        {

          /* Order in which the expressions arrive here depends on whether

             they are from data statements or F95 style declarations.

             Therefore, check which is the most recent.  */

          expr = (LOCATION_LINE (init->where.lb->location)

                  > LOCATION_LINE (rvalue->where.lb->location))

               ? init : rvalue;

          gfc_notify_std (GFC_STD_GNU, "Extension: re-initialization "

                          "of '%s' at %L", symbol->name, &expr->where);

        }

      expr = gfc_copy_expr (rvalue);

      if (!gfc_compare_types (&lvalue->ts, &expr->ts))

        gfc_convert_type (expr, &lvalue->ts, 0);

    }

  if (last_con == NULL)

    symbol->value = expr;

  else

    last_con->expr = expr;

  return SUCCESS;

}

/* Similarly, but initialize REPEAT consecutive values in LVALUE the same

   value in RVALUE.  For the nonce, LVALUE must refer to a full array, not

   an array section.  */

void

gfc_assign_data_value_range (gfc_expr *lvalue, gfc_expr *rvalue,

                             mpz_t index, mpz_t repeat)

{

  gfc_ref *ref;

  gfc_expr *init, *expr;

  gfc_constructor *con, *last_con;

  gfc_constructor *pred;

  gfc_symbol *symbol;

  gfc_typespec *last_ts;

  mpz_t offset;

  splay_tree spt;

  splay_tree_node sptn;

  symbol = lvalue->symtree->n.sym;

  init = symbol->value;

  last_ts = &symbol->ts;

  last_con = NULL;

  mpz_init_set_si (offset, 0);

  /* Find/create the parent expressions for subobject references.  */

  for (ref = lvalue->ref; ref; ref = ref->next)

    {

      /* Use the existing initializer expression if it exists.

         Otherwise create a new one.  */

      if (init == NULL)

        expr = gfc_get_expr ();

      else

        expr = init;

      /* Find or create this element.  */

      switch (ref->type)

        {

        case REF_ARRAY:

          if (init == NULL)

            {

              /* The element typespec will be the same as the array

                 typespec.  */

              expr->ts = *last_ts;

              /* Setup the expression to hold the constructor.  */

              expr->expr_type = EXPR_ARRAY;

              expr->rank = ref->u.ar.as->rank;

            }

          else

            gcc_assert (expr->expr_type == EXPR_ARRAY);

          if (ref->u.ar.type == AR_ELEMENT)

            {

              get_array_index (&ref->u.ar, &offset);

              /* This had better not be the bottom of the reference.

                 We can still get to a full array via a component.  */

              gcc_assert (ref->next != NULL);

            }

          else

            {

              mpz_set (offset, index);

              /* We're at a full array or an array section.  This means

                 that we've better have found a full array, and that we're

                 at the bottom of the reference.  */

              gcc_assert (ref->u.ar.type == AR_FULL);

              gcc_assert (ref->next == NULL);

            }

          /* Find the same element in the existing constructor.  */

          /* Splay tree containing offset and gfc_constructor.  */

          spt = expr->con_by_offset;

          if (spt == NULL)

            {

               spt = splay_tree_new (splay_tree_compare_ints, NULL, NULL);

               expr->con_by_offset = spt;

               con = NULL;

            }

          else

            con = find_con_by_offset (spt, offset);

          if (con == NULL)

            {

              splay_tree_key j;

              /* Create a new constructor.  */

              con = gfc_get_constructor ();

              mpz_set (con->n.offset, offset);

              j = (splay_tree_key) mpz_get_si (offset);

              if (ref->next == NULL)

                mpz_set (con->repeat, repeat);

              sptn = splay_tree_insert (spt, j, (splay_tree_value) con);

              /* Fix up the linked list.  */

              sptn = splay_tree_predecessor (spt, j);

              if (sptn == NULL)

                {  /* Insert at the head.  */

                   con->next = expr->value.constructor;

                   expr->value.constructor = con;

                }

              else

                {  /* Insert in the chain.  */

                   pred = (gfc_constructor*) sptn->value;

                   con->next = pred->next;

                   pred->next = con;

                }

            }

          else

            gcc_assert (ref->next != NULL);

          break;

        case REF_COMPONENT:

          if (init == NULL)

            {

              /* Setup the expression to hold the constructor.  */

              expr->expr_type = EXPR_STRUCTURE;

              expr->ts.type = BT_DERIVED;

              expr->ts.u.derived = ref->u.c.sym;

            }

          else

            gcc_assert (expr->expr_type == EXPR_STRUCTURE);

          last_ts = &ref->u.c.component->ts;

          /* Find the same element in the existing constructor.  */

          con = expr->value.constructor;

          con = find_con_by_component (ref->u.c.component, con);

          if (con == NULL)

            {

              /* Create a new constructor.  */

              con = gfc_get_constructor ();

              con->n.component = ref->u.c.component;

              con->next = expr->value.constructor;

              expr->value.constructor = con;

            }

          /* Since we're only intending to initialize arrays here,

             there better be an inner reference.  */

          gcc_assert (ref->next != NULL);

          break;

        case REF_SUBSTRING:

        default:

          gcc_unreachable ();

        }

      if (init == NULL)

        {

          /* Point the container at the new expression.  */

          if (last_con == NULL)

            symbol->value = expr;

          else

            last_con->expr = expr;

        }

      init = con->expr;

      last_con = con;

    }

  if (last_ts->type == BT_CHARACTER)

    expr = create_character_intializer (init, last_ts, NULL, rvalue);

  else

    {

      /* We should never be overwriting an existing initializer.  */

      gcc_assert (!init);

      expr = gfc_copy_expr (rvalue);

      if (!gfc_compare_types (&lvalue->ts, &expr->ts))

        gfc_convert_type (expr, &lvalue->ts, 0);

    }

  if (last_con == NULL)

    symbol->value = expr;

  else

    last_con->expr = expr;

}

/* Modify the index of array section and re-calculate the array offset.  */

void

gfc_advance_section (mpz_t *section_index, gfc_array_ref *ar,

                     mpz_t *offset_ret)

{

  int i;

  mpz_t delta;

  mpz_t tmp;

  bool forwards;

  int cmp;

  for (i = 0; i < ar->dimen; i++)

    {

      if (ar->dimen_type[i] != DIMEN_RANGE)

        continue;

      if (ar->stride[i])

        {

          mpz_add (section_index[i], section_index[i],

                   ar->stride[i]->value.integer);

        if (mpz_cmp_si (ar->stride[i]->value.integer, 0) >= 0)

          forwards = true;

        else

          forwards = false;

        }

      else

        {

          mpz_add_ui (section_index[i], section_index[i], 1);

          forwards = true;

        }

      if (ar->end[i])

        cmp = mpz_cmp (section_index[i], ar->end[i]->value.integer);

      else

        cmp = mpz_cmp (section_index[i], ar->as->upper[i]->value.integer);

      if ((cmp > 0 && forwards) || (cmp < 0 && !forwards))

        {

          /* Reset index to start, then loop to advance the next index.  */

          if (ar->start[i])

            mpz_set (section_index[i], ar->start[i]->value.integer);

          else

            mpz_set (section_index[i], ar->as->lower[i]->value.integer);

        }

      else

        break;

    }

  mpz_set_si (*offset_ret, 0);

  mpz_init_set_si (delta, 1);