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/* Supporting functions for resolving DATA statement.

   Copyright (C) 2002, 2003, 2004, 2005 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 2, 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 COPYING.  If not, write to the Free

Software Foundation, 51 Franklin Street, Fifth Floor,Boston, MA

02110-1301, USA.  */

/* Notes for DATA statement implementation:

   We first assign initial value to each symbol by gfc_assign_data_value

   during resolveing 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"

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;

  try re;

  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]);

      re = 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 (mpz_t offset, gfc_constructor *con)

{

  mpz_t tmp;

  gfc_constructor *ret = NULL;

  mpz_init (tmp);

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

    {

      int cmp = mpz_cmp (offset, con->n.offset);

      /* We retain a sorted list, so if we're too large, we're done.  */

      if (cmp < 0)

        break;

      /* Yaye for exact matches.  */

      if (cmp == 0)

        {

          ret = con;

          break;

        }

      /* If the constructor element is a range, match any element.  */

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

        {

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

          if (mpz_cmp (offset, tmp) < 0)

            {

              ret = con;

              break;

            }

        }

    }

  mpz_clear (tmp);

  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 thh 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;

  int start;

  int end;

  char *dest;

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

  if (init == NULL)

    {

      /* Create a new initializer.  */

      init = gfc_get_expr ();

      init->expr_type = EXPR_CONSTANT;

      init->ts = *ts;

      dest = gfc_getmem (len);

      init->value.character.length = len;

      init->value.character.string = dest;

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

      if (ref != NULL)

        memset (dest, ' ', len);

    }

  else

    dest = init->value.character.string;

  if (ref)

    {

      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).  */

      gfc_extract_int (ref->u.ss.start, &start);

      start--;

      gfc_extract_int (ref->u.ss.end, &end);

    }

  else

    {

      /* Set the whole string.  */

      start = 0;

      end = len;

    }

  /* Copy the initial value.  */

  len = rvalue->value.character.length;

  if (len > end - start)

    len = end - start;

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

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

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

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

  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.  */

void

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_symbol *symbol;

  gfc_typespec *last_ts;

  mpz_t offset;

  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 br 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 == 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);

          else

            mpz_set (offset, index);

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

          con = expr->value.constructor;

          con = find_con_by_offset (offset, con);

          if (con == NULL)

            {

              /* Create a new constructor.  */

              con = gfc_get_constructor ();

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

              gfc_insert_constructor (expr, 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.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)

    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 = (init->where.lb->linenum > rvalue->where.lb->linenum) ?

                    init : rvalue;

          gfc_notify_std (GFC_STD_GNU, "Extension: re-initialization "

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

          return;

        }

      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;

}

/* 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_symbol *symbol;

  gfc_typespec *last_ts;

  mpz_t offset;

  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.  */

          con = expr->value.constructor;

          con = find_con_by_offset (offset, con);

          /* Create a new constructor.  */

          if (con == NULL)

            {

              con = gfc_get_constructor ();

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

              if (ref->next == NULL)

                mpz_set (con->repeat, repeat);

              gfc_insert_constructor (expr, 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.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);

  mpz_init (tmp);

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

    {

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

      mpz_mul (tmp, tmp, delta);

      mpz_add (*offset_ret, tmp, *offset_ret);

      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 (tmp);

  mpz_clear (delta);

}

/* Rearrange a structure constructor so the elements are in the specified

   order.  Also insert NULL entries if necessary.  */

static void

formalize_structure_cons (gfc_expr * expr)

{

  gfc_constructor *head;

  gfc_constructor *tail;

  gfc_constructor *cur;

  gfc_constructor *last;

  gfc_constructor *c;

  gfc_component *order;

  c = expr->value.constructor;

  /* Constructor is already formalized.  */

  if (c->n.component == NULL)

    return;

  head = tail = NULL;

  for (order = expr->ts.derived->components; order; order = order->next)

    {

      /* Find the next component.  */

      last = NULL;

      cur = c;

      while (cur != NULL && cur->n.component != order)

        {

          last = cur;

          cur = cur->next;

        }

      if (cur == NULL)

        {

          /* Create a new one.  */

          cur = gfc_get_constructor ();

        }

      else

        {

          /* Remove it from the chain.  */

          if (last == NULL)

            c = cur->next;

          else

            last->next = cur->next;

          cur->next = NULL;

          formalize_init_expr (cur->expr);

        }

      /* Add it to the new constructor.  */

      if (head == NULL)

        head = tail = cur;

      else

        {

          tail->next = cur;

          tail = tail->next;

        }

    }

  gcc_assert (c == NULL);

  expr->value.constructor = head;

}

/* Make sure an initialization expression is in normalized form.  Ie. all

   elements of the constructors are in the correct order.  */

static void

formalize_init_expr (gfc_expr * expr)

{

  expr_t type;

  gfc_constructor *c;

  if (expr == NULL)

    return;

  type = expr->expr_type;

  switch (type)

    {

    case EXPR_ARRAY:

      c = expr->value.constructor;

      while (c)

        {

          formalize_init_expr (c->expr);

          c = c->next;

        }

      break;

    case EXPR_STRUCTURE:

      formalize_structure_cons (expr);

      break;

    default:

      break;

    }

}

/* Resolve symbol's initial value after all data statement.  */

void

gfc_formalize_init_value (gfc_symbol *sym)

{

  formalize_init_expr (sym->value);

}

/* Get the integer value into RET_AS and SECTION from AS and AR, and return

   offset.  */

void

gfc_get_section_index (gfc_array_ref *ar, mpz_t *section_index, mpz_t *offset)

{

  int i;

  mpz_t delta;

  mpz_t tmp;

  mpz_set_si (*offset, 0);

  mpz_init (tmp);

  mpz_init_set_si (delta, 1);

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

    {

      mpz_init (section_index[i]);

      switch (ar->dimen_type[i])

        {

        case DIMEN_ELEMENT:

        case DIMEN_RANGE:

          if (ar->start[i])

            {

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

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