gcc/ada:

[pf3gnuchains/gcc-fork.git] / gcc / fortran / trans-decl.c

/* Backend function setup
   Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
   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-decl.c -- Handling of backend function and variable decls, etc */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "tree-dump.h"
#include "gimple.h"     /* For create_tmp_var_raw.  */
#include "ggc.h"
#include "toplev.h"     /* For announce_function/internal_error.  */
#include "output.h"     /* For decl_default_tls_model.  */
#include "target.h"
#include "function.h"
#include "flags.h"
#include "cgraph.h"
#include "debug.h"
#include "gfortran.h"
#include "pointer-set.h"
#include "constructor.h"
#include "trans.h"
#include "trans-types.h"
#include "trans-array.h"
#include "trans-const.h"
/* Only for gfc_trans_code.  Shouldn't need to include this.  */
#include "trans-stmt.h"

#define MAX_LABEL_VALUE 99999


/* Holds the result of the function if no result variable specified.  */

static GTY(()) tree current_fake_result_decl;
static GTY(()) tree parent_fake_result_decl;

static GTY(()) tree current_function_return_label;


/* Holds the variable DECLs for the current function.  */

static GTY(()) tree saved_function_decls;
static GTY(()) tree saved_parent_function_decls;

static struct pointer_set_t *nonlocal_dummy_decl_pset;
static GTY(()) tree nonlocal_dummy_decls;

/* Holds the variable DECLs that are locals.  */

static GTY(()) tree saved_local_decls;

/* The namespace of the module we're currently generating.  Only used while
   outputting decls for module variables.  Do not rely on this being set.  */

static gfc_namespace *module_namespace;


/* List of static constructor functions.  */

tree gfc_static_ctors;


/* Function declarations for builtin library functions.  */

tree gfor_fndecl_pause_numeric;
tree gfor_fndecl_pause_string;
tree gfor_fndecl_stop_numeric;
tree gfor_fndecl_stop_string;
tree gfor_fndecl_error_stop_numeric;
tree gfor_fndecl_error_stop_string;
tree gfor_fndecl_runtime_error;
tree gfor_fndecl_runtime_error_at;
tree gfor_fndecl_runtime_warning_at;
tree gfor_fndecl_os_error;
tree gfor_fndecl_generate_error;
tree gfor_fndecl_set_args;
tree gfor_fndecl_set_fpe;
tree gfor_fndecl_set_options;
tree gfor_fndecl_set_convert;
tree gfor_fndecl_set_record_marker;
tree gfor_fndecl_set_max_subrecord_length;
tree gfor_fndecl_ctime;
tree gfor_fndecl_fdate;
tree gfor_fndecl_ttynam;
tree gfor_fndecl_in_pack;
tree gfor_fndecl_in_unpack;
tree gfor_fndecl_associated;


/* Math functions.  Many other math functions are handled in
   trans-intrinsic.c.  */

gfc_powdecl_list gfor_fndecl_math_powi[4][3];
tree gfor_fndecl_math_ishftc4;
tree gfor_fndecl_math_ishftc8;
tree gfor_fndecl_math_ishftc16;


/* String functions.  */

tree gfor_fndecl_compare_string;
tree gfor_fndecl_concat_string;
tree gfor_fndecl_string_len_trim;
tree gfor_fndecl_string_index;
tree gfor_fndecl_string_scan;
tree gfor_fndecl_string_verify;
tree gfor_fndecl_string_trim;
tree gfor_fndecl_string_minmax;
tree gfor_fndecl_adjustl;
tree gfor_fndecl_adjustr;
tree gfor_fndecl_select_string;
tree gfor_fndecl_compare_string_char4;
tree gfor_fndecl_concat_string_char4;
tree gfor_fndecl_string_len_trim_char4;
tree gfor_fndecl_string_index_char4;
tree gfor_fndecl_string_scan_char4;
tree gfor_fndecl_string_verify_char4;
tree gfor_fndecl_string_trim_char4;
tree gfor_fndecl_string_minmax_char4;
tree gfor_fndecl_adjustl_char4;
tree gfor_fndecl_adjustr_char4;
tree gfor_fndecl_select_string_char4;


/* Conversion between character kinds.  */
tree gfor_fndecl_convert_char1_to_char4;
tree gfor_fndecl_convert_char4_to_char1;


/* Other misc. runtime library functions.  */

tree gfor_fndecl_size0;
tree gfor_fndecl_size1;
tree gfor_fndecl_iargc;
tree gfor_fndecl_clz128;
tree gfor_fndecl_ctz128;

/* Intrinsic functions implemented in Fortran.  */
tree gfor_fndecl_sc_kind;
tree gfor_fndecl_si_kind;
tree gfor_fndecl_sr_kind;

/* BLAS gemm functions.  */
tree gfor_fndecl_sgemm;
tree gfor_fndecl_dgemm;
tree gfor_fndecl_cgemm;
tree gfor_fndecl_zgemm;


static void
gfc_add_decl_to_parent_function (tree decl)
{
  gcc_assert (decl);
  DECL_CONTEXT (decl) = DECL_CONTEXT (current_function_decl);
  DECL_NONLOCAL (decl) = 1;
  TREE_CHAIN (decl) = saved_parent_function_decls;
  saved_parent_function_decls = decl;
}

void
gfc_add_decl_to_function (tree decl)
{
  gcc_assert (decl);
  TREE_USED (decl) = 1;
  DECL_CONTEXT (decl) = current_function_decl;
  TREE_CHAIN (decl) = saved_function_decls;
  saved_function_decls = decl;
}

static void
add_decl_as_local (tree decl)
{
  gcc_assert (decl);
  TREE_USED (decl) = 1;
  DECL_CONTEXT (decl) = current_function_decl;
  TREE_CHAIN (decl) = saved_local_decls;
  saved_local_decls = decl;
}


/* Build a  backend label declaration.  Set TREE_USED for named labels.
   The context of the label is always the current_function_decl.  All
   labels are marked artificial.  */

tree
gfc_build_label_decl (tree label_id)
{
  /* 2^32 temporaries should be enough.  */
  static unsigned int tmp_num = 1;
  tree label_decl;
  char *label_name;

  if (label_id == NULL_TREE)
    {
      /* Build an internal label name.  */
      ASM_FORMAT_PRIVATE_NAME (label_name, "L", tmp_num++);
      label_id = get_identifier (label_name);
    }
  else
    label_name = NULL;

  /* Build the LABEL_DECL node. Labels have no type.  */
  label_decl = build_decl (input_location,
                           LABEL_DECL, label_id, void_type_node);
  DECL_CONTEXT (label_decl) = current_function_decl;
  DECL_MODE (label_decl) = VOIDmode;

  /* We always define the label as used, even if the original source
     file never references the label.  We don't want all kinds of
     spurious warnings for old-style Fortran code with too many
     labels.  */
  TREE_USED (label_decl) = 1;

  DECL_ARTIFICIAL (label_decl) = 1;
  return label_decl;
}


/* Returns the return label for the current function.  */

tree
gfc_get_return_label (void)
{
  char name[GFC_MAX_SYMBOL_LEN + 10];

  if (current_function_return_label)
    return current_function_return_label;

  sprintf (name, "__return_%s",
           IDENTIFIER_POINTER (DECL_NAME (current_function_decl)));

  current_function_return_label =
    gfc_build_label_decl (get_identifier (name));

  DECL_ARTIFICIAL (current_function_return_label) = 1;

  return current_function_return_label;
}


/* Set the backend source location of a decl.  */

void
gfc_set_decl_location (tree decl, locus * loc)
{
  DECL_SOURCE_LOCATION (decl) = loc->lb->location;
}


/* Return the backend label declaration for a given label structure,
   or create it if it doesn't exist yet.  */

tree
gfc_get_label_decl (gfc_st_label * lp)
{
  if (lp->backend_decl)
    return lp->backend_decl;
  else
    {
      char label_name[GFC_MAX_SYMBOL_LEN + 1];
      tree label_decl;

      /* Validate the label declaration from the front end.  */
      gcc_assert (lp != NULL && lp->value <= MAX_LABEL_VALUE);

      /* Build a mangled name for the label.  */
      sprintf (label_name, "__label_%.6d", lp->value);

      /* Build the LABEL_DECL node.  */
      label_decl = gfc_build_label_decl (get_identifier (label_name));

      /* Tell the debugger where the label came from.  */
      if (lp->value <= MAX_LABEL_VALUE) /* An internal label.  */
        gfc_set_decl_location (label_decl, &lp->where);
      else
        DECL_ARTIFICIAL (label_decl) = 1;

      /* Store the label in the label list and return the LABEL_DECL.  */
      lp->backend_decl = label_decl;
      return label_decl;
    }
}


/* Convert a gfc_symbol to an identifier of the same name.  */

static tree
gfc_sym_identifier (gfc_symbol * sym)
{
  if (sym->attr.is_main_program && strcmp (sym->name, "main") == 0)
    return (get_identifier ("MAIN__"));
  else
    return (get_identifier (sym->name));
}


/* Construct mangled name from symbol name.  */

static tree
gfc_sym_mangled_identifier (gfc_symbol * sym)
{
  char name[GFC_MAX_MANGLED_SYMBOL_LEN + 1];

  /* Prevent the mangling of identifiers that have an assigned
     binding label (mainly those that are bind(c)).  */
  if (sym->attr.is_bind_c == 1
      && sym->binding_label[0] != '\0')
    return get_identifier(sym->binding_label);
  
  if (sym->module == NULL)
    return gfc_sym_identifier (sym);
  else
    {
      snprintf (name, sizeof name, "__%s_MOD_%s", sym->module, sym->name);
      return get_identifier (name);
    }
}


/* Construct mangled function name from symbol name.  */

static tree
gfc_sym_mangled_function_id (gfc_symbol * sym)
{
  int has_underscore;
  char name[GFC_MAX_MANGLED_SYMBOL_LEN + 1];

  /* It may be possible to simply use the binding label if it's
     provided, and remove the other checks.  Then we could use it
     for other things if we wished.  */
  if ((sym->attr.is_bind_c == 1 || sym->attr.is_iso_c == 1) &&
      sym->binding_label[0] != '\0')
    /* use the binding label rather than the mangled name */
    return get_identifier (sym->binding_label);

  if (sym->module == NULL || sym->attr.proc == PROC_EXTERNAL
      || (sym->module != NULL && (sym->attr.external
            || sym->attr.if_source == IFSRC_IFBODY)))
    {
      /* Main program is mangled into MAIN__.  */
      if (sym->attr.is_main_program)
        return get_identifier ("MAIN__");

      /* Intrinsic procedures are never mangled.  */
      if (sym->attr.proc == PROC_INTRINSIC)
        return get_identifier (sym->name);

      if (gfc_option.flag_underscoring)
        {
          has_underscore = strchr (sym->name, '_') != 0;
          if (gfc_option.flag_second_underscore && has_underscore)
            snprintf (name, sizeof name, "%s__", sym->name);
          else
            snprintf (name, sizeof name, "%s_", sym->name);
          return get_identifier (name);
        }
      else
        return get_identifier (sym->name);
    }
  else
    {
      snprintf (name, sizeof name, "__%s_MOD_%s", sym->module, sym->name);
      return get_identifier (name);
    }
}


void
gfc_set_decl_assembler_name (tree decl, tree name)
{
  tree target_mangled = targetm.mangle_decl_assembler_name (decl, name);
  SET_DECL_ASSEMBLER_NAME (decl, target_mangled);
}


/* Returns true if a variable of specified size should go on the stack.  */

int
gfc_can_put_var_on_stack (tree size)
{
  unsigned HOST_WIDE_INT low;

  if (!INTEGER_CST_P (size))
    return 0;

  if (gfc_option.flag_max_stack_var_size < 0)
    return 1;

  if (TREE_INT_CST_HIGH (size) != 0)
    return 0;

  low = TREE_INT_CST_LOW (size);
  if (low > (unsigned HOST_WIDE_INT) gfc_option.flag_max_stack_var_size)
    return 0;

/* TODO: Set a per-function stack size limit.  */

  return 1;
}


/* gfc_finish_cray_pointee sets DECL_VALUE_EXPR for a Cray pointee to
   an expression involving its corresponding pointer.  There are
   2 cases; one for variable size arrays, and one for everything else,
   because variable-sized arrays require one fewer level of
   indirection.  */

static void
gfc_finish_cray_pointee (tree decl, gfc_symbol *sym)
{
  tree ptr_decl = gfc_get_symbol_decl (sym->cp_pointer);
  tree value;

  /* Parameters need to be dereferenced.  */
  if (sym->cp_pointer->attr.dummy) 
    ptr_decl = build_fold_indirect_ref_loc (input_location,
                                        ptr_decl);

  /* Check to see if we're dealing with a variable-sized array.  */
  if (sym->attr.dimension
      && TREE_CODE (TREE_TYPE (decl)) == POINTER_TYPE) 
    {  
      /* These decls will be dereferenced later, so we don't dereference
         them here.  */
      value = convert (TREE_TYPE (decl), ptr_decl);
    }
  else
    {
      ptr_decl = convert (build_pointer_type (TREE_TYPE (decl)),
                          ptr_decl);
      value = build_fold_indirect_ref_loc (input_location,
                                       ptr_decl);
    }

  SET_DECL_VALUE_EXPR (decl, value);
  DECL_HAS_VALUE_EXPR_P (decl) = 1;
  GFC_DECL_CRAY_POINTEE (decl) = 1;
  /* This is a fake variable just for debugging purposes.  */
  TREE_ASM_WRITTEN (decl) = 1;
}


/* Finish processing of a declaration without an initial value.  */

static void
gfc_finish_decl (tree decl)
{
  gcc_assert (TREE_CODE (decl) == PARM_DECL
              || DECL_INITIAL (decl) == NULL_TREE);

  if (TREE_CODE (decl) != VAR_DECL)
    return;

  if (DECL_SIZE (decl) == NULL_TREE
      && TYPE_SIZE (TREE_TYPE (decl)) != NULL_TREE)
    layout_decl (decl, 0);

  /* A few consistency checks.  */
  /* A static variable with an incomplete type is an error if it is
     initialized. Also if it is not file scope. Otherwise, let it
     through, but if it is not `extern' then it may cause an error
     message later.  */
  /* An automatic variable with an incomplete type is an error.  */

  /* We should know the storage size.  */
  gcc_assert (DECL_SIZE (decl) != NULL_TREE
              || (TREE_STATIC (decl) 
                  ? (!DECL_INITIAL (decl) || !DECL_CONTEXT (decl))
                  : DECL_EXTERNAL (decl)));

  /* The storage size should be constant.  */
  gcc_assert ((!DECL_EXTERNAL (decl) && !TREE_STATIC (decl))
              || !DECL_SIZE (decl)
              || TREE_CODE (DECL_SIZE (decl)) == INTEGER_CST);
}


/* Apply symbol attributes to a variable, and add it to the function scope.  */

static void
gfc_finish_var_decl (tree decl, gfc_symbol * sym)
{
  tree new_type;
  /* TREE_ADDRESSABLE means the address of this variable is actually needed.
     This is the equivalent of the TARGET variables.
     We also need to set this if the variable is passed by reference in a
     CALL statement.  */

  /* Set DECL_VALUE_EXPR for Cray Pointees.  */
  if (sym->attr.cray_pointee)
    gfc_finish_cray_pointee (decl, sym);

  if (sym->attr.target)
    TREE_ADDRESSABLE (decl) = 1;
  /* If it wasn't used we wouldn't be getting it.  */
  TREE_USED (decl) = 1;

  /* Chain this decl to the pending declarations.  Don't do pushdecl()
     because this would add them to the current scope rather than the
     function scope.  */
  if (current_function_decl != NULL_TREE)
    {
      if (sym->ns->proc_name->backend_decl == current_function_decl
          || sym->result == sym)
        gfc_add_decl_to_function (decl);
      else if (sym->ns->proc_name->attr.flavor == FL_LABEL)
        /* This is a BLOCK construct.  */
        add_decl_as_local (decl);
      else
        gfc_add_decl_to_parent_function (decl);
    }

  if (sym->attr.cray_pointee)
    return;

  if(sym->attr.is_bind_c == 1)
    {
      /* We need to put variables that are bind(c) into the common
         segment of the object file, because this is what C would do.
         gfortran would typically put them in either the BSS or
         initialized data segments, and only mark them as common if
         they were part of common blocks.  However, if they are not put
         into common space, then C cannot initialize global Fortran
         variables that it interoperates with and the draft says that
         either Fortran or C should be able to initialize it (but not
         both, of course.) (J3/04-007, section 15.3).  */
      TREE_PUBLIC(decl) = 1;
      DECL_COMMON(decl) = 1;
    }
  
  /* If a variable is USE associated, it's always external.  */
  if (sym->attr.use_assoc)
    {
      DECL_EXTERNAL (decl) = 1;
      TREE_PUBLIC (decl) = 1;
    }
  else if (sym->module && !sym->attr.result && !sym->attr.dummy)
    {
      /* TODO: Don't set sym->module for result or dummy variables.  */
      gcc_assert (current_function_decl == NULL_TREE || sym->result == sym);
      /* This is the declaration of a module variable.  */
      TREE_PUBLIC (decl) = 1;
      TREE_STATIC (decl) = 1;
    }

  /* Derived types are a bit peculiar because of the possibility of
     a default initializer; this must be applied each time the variable
     comes into scope it therefore need not be static.  These variables
     are SAVE_NONE but have an initializer.  Otherwise explicitly
     initialized variables are SAVE_IMPLICIT and explicitly saved are
     SAVE_EXPLICIT.  */
  if (!sym->attr.use_assoc
        && (sym->attr.save != SAVE_NONE || sym->attr.data
              || (sym->value && sym->ns->proc_name->attr.is_main_program)))
    TREE_STATIC (decl) = 1;

  if (sym->attr.volatile_)
    {
      TREE_THIS_VOLATILE (decl) = 1;
      new_type = build_qualified_type (TREE_TYPE (decl), TYPE_QUAL_VOLATILE);
      TREE_TYPE (decl) = new_type;
    } 

  /* Keep variables larger than max-stack-var-size off stack.  */
  if (!sym->ns->proc_name->attr.recursive
      && INTEGER_CST_P (DECL_SIZE_UNIT (decl))
      && !gfc_can_put_var_on_stack (DECL_SIZE_UNIT (decl))
         /* Put variable length auto array pointers always into stack.  */
      && (TREE_CODE (TREE_TYPE (decl)) != POINTER_TYPE
          || sym->attr.dimension == 0
          || sym->as->type != AS_EXPLICIT
          || sym->attr.pointer
          || sym->attr.allocatable)
      && !DECL_ARTIFICIAL (decl))
    TREE_STATIC (decl) = 1;

  /* Handle threadprivate variables.  */
  if (sym->attr.threadprivate
      && (TREE_STATIC (decl) || DECL_EXTERNAL (decl)))
    DECL_TLS_MODEL (decl) = decl_default_tls_model (decl);

  if (!sym->attr.target
      && !sym->attr.pointer
      && !sym->attr.cray_pointee
      && !sym->attr.proc_pointer)
    DECL_RESTRICTED_P (decl) = 1;
}


/* Allocate the lang-specific part of a decl.  */

void
gfc_allocate_lang_decl (tree decl)
{
  DECL_LANG_SPECIFIC (decl) = ggc_alloc_cleared_lang_decl(sizeof
                                                          (struct lang_decl));
}

/* Remember a symbol to generate initialization/cleanup code at function
   entry/exit.  */

static void
gfc_defer_symbol_init (gfc_symbol * sym)
{
  gfc_symbol *p;
  gfc_symbol *last;
  gfc_symbol *head;

  /* Don't add a symbol twice.  */
  if (sym->tlink)
    return;

  last = head = sym->ns->proc_name;
  p = last->tlink;

  /* Make sure that setup code for dummy variables which are used in the
     setup of other variables is generated first.  */
  if (sym->attr.dummy)
    {
      /* Find the first dummy arg seen after us, or the first non-dummy arg.
         This is a circular list, so don't go past the head.  */
      while (p != head
             && (!p->attr.dummy || p->dummy_order > sym->dummy_order))
        {
          last = p;
          p = p->tlink;
        }
    }
  /* Insert in between last and p.  */
  last->tlink = sym;
  sym->tlink = p;
}


/* Create an array index type variable with function scope.  */

static tree
create_index_var (const char * pfx, int nest)
{
  tree decl;

  decl = gfc_create_var_np (gfc_array_index_type, pfx);
  if (nest)
    gfc_add_decl_to_parent_function (decl);
  else
    gfc_add_decl_to_function (decl);
  return decl;
}


/* Create variables to hold all the non-constant bits of info for a
   descriptorless array.  Remember these in the lang-specific part of the
   type.  */

static void
gfc_build_qualified_array (tree decl, gfc_symbol * sym)
{
  tree type;
  int dim;
  int nest;

  type = TREE_TYPE (decl);

  /* We just use the descriptor, if there is one.  */
  if (GFC_DESCRIPTOR_TYPE_P (type))
    return;

  gcc_assert (GFC_ARRAY_TYPE_P (type));
  nest = (sym->ns->proc_name->backend_decl != current_function_decl)
         && !sym->attr.contained;

  for (dim = 0; dim < GFC_TYPE_ARRAY_RANK (type); dim++)
    {
      if (GFC_TYPE_ARRAY_LBOUND (type, dim) == NULL_TREE)
        {
          GFC_TYPE_ARRAY_LBOUND (type, dim) = create_index_var ("lbound", nest);
          TREE_NO_WARNING (GFC_TYPE_ARRAY_LBOUND (type, dim)) = 1;
        }
      /* Don't try to use the unknown bound for assumed shape arrays.  */
      if (GFC_TYPE_ARRAY_UBOUND (type, dim) == NULL_TREE
          && (sym->as->type != AS_ASSUMED_SIZE
              || dim < GFC_TYPE_ARRAY_RANK (type) - 1))
        {
          GFC_TYPE_ARRAY_UBOUND (type, dim) = create_index_var ("ubound", nest);
          TREE_NO_WARNING (GFC_TYPE_ARRAY_UBOUND (type, dim)) = 1;
        }

      if (GFC_TYPE_ARRAY_STRIDE (type, dim) == NULL_TREE)
        {
          GFC_TYPE_ARRAY_STRIDE (type, dim) = create_index_var ("stride", nest);
          TREE_NO_WARNING (GFC_TYPE_ARRAY_STRIDE (type, dim)) = 1;
        }
    }
  if (GFC_TYPE_ARRAY_OFFSET (type) == NULL_TREE)
    {
      GFC_TYPE_ARRAY_OFFSET (type) = gfc_create_var_np (gfc_array_index_type,
                                                        "offset");
      TREE_NO_WARNING (GFC_TYPE_ARRAY_OFFSET (type)) = 1;

      if (nest)
        gfc_add_decl_to_parent_function (GFC_TYPE_ARRAY_OFFSET (type));
      else
        gfc_add_decl_to_function (GFC_TYPE_ARRAY_OFFSET (type));
    }

  if (GFC_TYPE_ARRAY_SIZE (type) == NULL_TREE
      && sym->as->type != AS_ASSUMED_SIZE)
    {
      GFC_TYPE_ARRAY_SIZE (type) = create_index_var ("size", nest);
      TREE_NO_WARNING (GFC_TYPE_ARRAY_SIZE (type)) = 1;
    }

  if (POINTER_TYPE_P (type))
    {
      gcc_assert (GFC_ARRAY_TYPE_P (TREE_TYPE (type)));
      gcc_assert (TYPE_LANG_SPECIFIC (type)
                  == TYPE_LANG_SPECIFIC (TREE_TYPE (type)));
      type = TREE_TYPE (type);
    }

  if (! COMPLETE_TYPE_P (type) && GFC_TYPE_ARRAY_SIZE (type))
    {
      tree size, range;

      size = fold_build2 (MINUS_EXPR, gfc_array_index_type,
                          GFC_TYPE_ARRAY_SIZE (type), gfc_index_one_node);
      range = build_range_type (gfc_array_index_type, gfc_index_zero_node,
                                size);
      TYPE_DOMAIN (type) = range;
      layout_type (type);
    }

  if (TYPE_NAME (type) != NULL_TREE
      && GFC_TYPE_ARRAY_UBOUND (type, sym->as->rank - 1) != NULL_TREE
      && TREE_CODE (GFC_TYPE_ARRAY_UBOUND (type, sym->as->rank - 1)) == VAR_DECL)
    {
      tree gtype = DECL_ORIGINAL_TYPE (TYPE_NAME (type));

      for (dim = 0; dim < sym->as->rank - 1; dim++)
        {
          gcc_assert (TREE_CODE (gtype) == ARRAY_TYPE);
          gtype = TREE_TYPE (gtype);
        }
      gcc_assert (TREE_CODE (gtype) == ARRAY_TYPE);
      if (TYPE_MAX_VALUE (TYPE_DOMAIN (gtype)) == NULL)
        TYPE_NAME (type) = NULL_TREE;
    }

  if (TYPE_NAME (type) == NULL_TREE)
    {
      tree gtype = TREE_TYPE (type), rtype, type_decl;

      for (dim = sym->as->rank - 1; dim >= 0; dim--)
        {
          tree lbound, ubound;
          lbound = GFC_TYPE_ARRAY_LBOUND (type, dim);
          ubound = GFC_TYPE_ARRAY_UBOUND (type, dim);
          rtype = build_range_type (gfc_array_index_type, lbound, ubound);
          gtype = build_array_type (gtype, rtype);
          /* Ensure the bound variables aren't optimized out at -O0.
             For -O1 and above they often will be optimized out, but
             can be tracked by VTA.  Also clear the artificial
             lbound.N or ubound.N DECL_NAME, so that it doesn't end up
             in debug info.  */
          if (lbound && TREE_CODE (lbound) == VAR_DECL
              && DECL_ARTIFICIAL (lbound) && DECL_IGNORED_P (lbound))
            {
              if (DECL_NAME (lbound)
                  && strstr (IDENTIFIER_POINTER (DECL_NAME (lbound)),
                             "lbound") != 0)
                DECL_NAME (lbound) = NULL_TREE;
              DECL_IGNORED_P (lbound) = 0;
            }
          if (ubound && TREE_CODE (ubound) == VAR_DECL
              && DECL_ARTIFICIAL (ubound) && DECL_IGNORED_P (ubound))
            {
              if (DECL_NAME (ubound)
                  && strstr (IDENTIFIER_POINTER (DECL_NAME (ubound)),
                             "ubound") != 0)
                DECL_NAME (ubound) = NULL_TREE;
              DECL_IGNORED_P (ubound) = 0;
            }
        }
      TYPE_NAME (type) = type_decl = build_decl (input_location,
                                                 TYPE_DECL, NULL, gtype);
      DECL_ORIGINAL_TYPE (type_decl) = gtype;
    }
}


/* For some dummy arguments we don't use the actual argument directly.
   Instead we create a local decl and use that.  This allows us to perform
   initialization, and construct full type information.  */

static tree
gfc_build_dummy_array_decl (gfc_symbol * sym, tree dummy)
{
  tree decl;
  tree type;
  gfc_array_spec *as;
  char *name;
  gfc_packed packed;
  int n;
  bool known_size;

  if (sym->attr.pointer || sym->attr.allocatable)
    return dummy;

  /* Add to list of variables if not a fake result variable.  */
  if (sym->attr.result || sym->attr.dummy)
    gfc_defer_symbol_init (sym);

  type = TREE_TYPE (dummy);
  gcc_assert (TREE_CODE (dummy) == PARM_DECL
          && POINTER_TYPE_P (type));

  /* Do we know the element size?  */
  known_size = sym->ts.type != BT_CHARACTER
          || INTEGER_CST_P (sym->ts.u.cl->backend_decl);
  
  if (known_size && !GFC_DESCRIPTOR_TYPE_P (TREE_TYPE (type)))
    {
      /* For descriptorless arrays with known element size the actual
         argument is sufficient.  */
      gcc_assert (GFC_ARRAY_TYPE_P (type));
      gfc_build_qualified_array (dummy, sym);
      return dummy;
    }

  type = TREE_TYPE (type);
  if (GFC_DESCRIPTOR_TYPE_P (type))
    {
      /* Create a descriptorless array pointer.  */
      as = sym->as;
      packed = PACKED_NO;

      /* Even when -frepack-arrays is used, symbols with TARGET attribute
         are not repacked.  */
      if (!gfc_option.flag_repack_arrays || sym->attr.target)
        {
          if (as->type == AS_ASSUMED_SIZE)
            packed = PACKED_FULL;
        }
      else
        {
          if (as->type == AS_EXPLICIT)
            {
              packed = PACKED_FULL;
              for (n = 0; n < as->rank; n++)
                {
                  if (!(as->upper[n]
                        && as->lower[n]
                        && as->upper[n]->expr_type == EXPR_CONSTANT
                        && as->lower[n]->expr_type == EXPR_CONSTANT))
                    packed = PACKED_PARTIAL;
                }
            }
          else
            packed = PACKED_PARTIAL;
        }

      type = gfc_typenode_for_spec (&sym->ts);
      type = gfc_get_nodesc_array_type (type, sym->as, packed,
                                        !sym->attr.target);
    }
  else
    {
      /* We now have an expression for the element size, so create a fully
         qualified type.  Reset sym->backend decl or this will just return the
         old type.  */
      DECL_ARTIFICIAL (sym->backend_decl) = 1;
      sym->backend_decl = NULL_TREE;
      type = gfc_sym_type (sym);
      packed = PACKED_FULL;
    }

  ASM_FORMAT_PRIVATE_NAME (name, IDENTIFIER_POINTER (DECL_NAME (dummy)), 0);
  decl = build_decl (input_location,
                     VAR_DECL, get_identifier (name), type);

  DECL_ARTIFICIAL (decl) = 1;
  TREE_PUBLIC (decl) = 0;
  TREE_STATIC (decl) = 0;
  DECL_EXTERNAL (decl) = 0;

  /* We should never get deferred shape arrays here.  We used to because of
     frontend bugs.  */
  gcc_assert (sym->as->type != AS_DEFERRED);

  if (packed == PACKED_PARTIAL)
    GFC_DECL_PARTIAL_PACKED_ARRAY (decl) = 1;
  else if (packed == PACKED_FULL)
    GFC_DECL_PACKED_ARRAY (decl) = 1;

  gfc_build_qualified_array (decl, sym);

  if (DECL_LANG_SPECIFIC (dummy))
    DECL_LANG_SPECIFIC (decl) = DECL_LANG_SPECIFIC (dummy);
  else
    gfc_allocate_lang_decl (decl);

  GFC_DECL_SAVED_DESCRIPTOR (decl) = dummy;

  if (sym->ns->proc_name->backend_decl == current_function_decl
      || sym->attr.contained)
    gfc_add_decl_to_function (decl);
  else
    gfc_add_decl_to_parent_function (decl);

  return decl;
}

/* For symbol SYM with GFC_DECL_SAVED_DESCRIPTOR used in contained
   function add a VAR_DECL to the current function with DECL_VALUE_EXPR
   pointing to the artificial variable for debug info purposes.  */

static void
gfc_nonlocal_dummy_array_decl (gfc_symbol *sym)
{
  tree decl, dummy;

  if (! nonlocal_dummy_decl_pset)
    nonlocal_dummy_decl_pset = pointer_set_create ();

  if (pointer_set_insert (nonlocal_dummy_decl_pset, sym->backend_decl))
    return;

  dummy = GFC_DECL_SAVED_DESCRIPTOR (sym->backend_decl);
  decl = build_decl (input_location, VAR_DECL, DECL_NAME (dummy),
                     TREE_TYPE (sym->backend_decl));
  DECL_ARTIFICIAL (decl) = 0;
  TREE_USED (decl) = 1;
  TREE_PUBLIC (decl) = 0;
  TREE_STATIC (decl) = 0;
  DECL_EXTERNAL (decl) = 0;
  if (DECL_BY_REFERENCE (dummy))
    DECL_BY_REFERENCE (decl) = 1;
  DECL_LANG_SPECIFIC (decl) = DECL_LANG_SPECIFIC (sym->backend_decl);
  SET_DECL_VALUE_EXPR (decl, sym->backend_decl);
  DECL_HAS_VALUE_EXPR_P (decl) = 1;
  DECL_CONTEXT (decl) = DECL_CONTEXT (sym->backend_decl);
  TREE_CHAIN (decl) = nonlocal_dummy_decls;
  nonlocal_dummy_decls = decl;
}

/* Return a constant or a variable to use as a string length.  Does not
   add the decl to the current scope.  */

static tree
gfc_create_string_length (gfc_symbol * sym)
{
  gcc_assert (sym->ts.u.cl);
  gfc_conv_const_charlen (sym->ts.u.cl);

  if (sym->ts.u.cl->backend_decl == NULL_TREE)
    {
      tree length;
      char name[GFC_MAX_MANGLED_SYMBOL_LEN + 2];

      /* Also prefix the mangled name.  */
      strcpy (&name[1], sym->name);
      name[0] = '.';
      length = build_decl (input_location,
                           VAR_DECL, get_identifier (name),
                           gfc_charlen_type_node);
      DECL_ARTIFICIAL (length) = 1;
      TREE_USED (length) = 1;
      if (sym->ns->proc_name->tlink != NULL)
        gfc_defer_symbol_init (sym);

      sym->ts.u.cl->backend_decl = length;
    }

  gcc_assert (sym->ts.u.cl->backend_decl != NULL_TREE);
  return sym->ts.u.cl->backend_decl;
}

/* If a variable is assigned a label, we add another two auxiliary
   variables.  */

static void
gfc_add_assign_aux_vars (gfc_symbol * sym)
{
  tree addr;
  tree length;
  tree decl;

  gcc_assert (sym->backend_decl);

  decl = sym->backend_decl;
  gfc_allocate_lang_decl (decl);
  GFC_DECL_ASSIGN (decl) = 1;
  length = build_decl (input_location,
                       VAR_DECL, create_tmp_var_name (sym->name),
                       gfc_charlen_type_node);
  addr = build_decl (input_location,
                     VAR_DECL, create_tmp_var_name (sym->name),
                     pvoid_type_node);
  gfc_finish_var_decl (length, sym);
  gfc_finish_var_decl (addr, sym);
  /*  STRING_LENGTH is also used as flag. Less than -1 means that
      ASSIGN_ADDR can not be used. Equal -1 means that ASSIGN_ADDR is the
      target label's address. Otherwise, value is the length of a format string
      and ASSIGN_ADDR is its address.  */
  if (TREE_STATIC (length))
    DECL_INITIAL (length) = build_int_cst (NULL_TREE, -2);
  else
    gfc_defer_symbol_init (sym);

  GFC_DECL_STRING_LEN (decl) = length;
  GFC_DECL_ASSIGN_ADDR (decl) = addr;
}


static tree
add_attributes_to_decl (symbol_attribute sym_attr, tree list)
{
  unsigned id;
  tree attr;

  for (id = 0; id < EXT_ATTR_NUM; id++)
    if (sym_attr.ext_attr & (1 << id))
      {
        attr = build_tree_list (
                 get_identifier (ext_attr_list[id].middle_end_name),
                                 NULL_TREE);
        list = chainon (list, attr);
      }

  return list;
}


/* Return the decl for a gfc_symbol, create it if it doesn't already
   exist.  */

tree
gfc_get_symbol_decl (gfc_symbol * sym)
{
  tree decl;
  tree length = NULL_TREE;
  tree attributes;
  int byref;

  gcc_assert (sym->attr.referenced
                || sym->attr.use_assoc
                || sym->ns->proc_name->attr.if_source == IFSRC_IFBODY);

  if (sym->ns && sym->ns->proc_name && sym->ns->proc_name->attr.function)
    byref = gfc_return_by_reference (sym->ns->proc_name);
  else
    byref = 0;

  /* Make sure that the vtab for the declared type is completed.  */
  if (sym->ts.type == BT_CLASS)
    {
      gfc_component *c = CLASS_DATA (sym);
      if (!c->ts.u.derived->backend_decl)
        gfc_find_derived_vtab (c->ts.u.derived, true);
    }

  if ((sym->attr.dummy && ! sym->attr.function) || (sym->attr.result && byref))
    {
      /* Return via extra parameter.  */
      if (sym->attr.result && byref
          && !sym->backend_decl)
        {
          sym->backend_decl =
            DECL_ARGUMENTS (sym->ns->proc_name->backend_decl);
          /* For entry master function skip over the __entry
             argument.  */
          if (sym->ns->proc_name->attr.entry_master)
            sym->backend_decl = TREE_CHAIN (sym->backend_decl);
        }

      /* Dummy variables should already have been created.  */
      gcc_assert (sym->backend_decl);

      /* Create a character length variable.  */
      if (sym->ts.type == BT_CHARACTER)
        {
          if (sym->ts.u.cl->backend_decl == NULL_TREE)
            length = gfc_create_string_length (sym);
          else
            length = sym->ts.u.cl->backend_decl;
          if (TREE_CODE (length) == VAR_DECL
              && DECL_CONTEXT (length) == NULL_TREE)
            {
              /* Add the string length to the same context as the symbol.  */
              if (DECL_CONTEXT (sym->backend_decl) == current_function_decl)
                gfc_add_decl_to_function (length);
              else
                gfc_add_decl_to_parent_function (length);

              gcc_assert (DECL_CONTEXT (sym->backend_decl) ==
                            DECL_CONTEXT (length));

              gfc_defer_symbol_init (sym);
            }
        }

      /* Use a copy of the descriptor for dummy arrays.  */
      if (sym->attr.dimension && !TREE_USED (sym->backend_decl))
        {
          decl = gfc_build_dummy_array_decl (sym, sym->backend_decl);
          /* Prevent the dummy from being detected as unused if it is copied.  */
          if (sym->backend_decl != NULL && decl != sym->backend_decl)
            DECL_ARTIFICIAL (sym->backend_decl) = 1;
          sym->backend_decl = decl;
        }

      TREE_USED (sym->backend_decl) = 1;
      if (sym->attr.assign && GFC_DECL_ASSIGN (sym->backend_decl) == 0)
        {
          gfc_add_assign_aux_vars (sym);
        }

      if (sym->attr.dimension
          && DECL_LANG_SPECIFIC (sym->backend_decl)
          && GFC_DECL_SAVED_DESCRIPTOR (sym->backend_decl)
          && DECL_CONTEXT (sym->backend_decl) != current_function_decl)
        gfc_nonlocal_dummy_array_decl (sym);

      return sym->backend_decl;
    }

  if (sym->backend_decl)
    return sym->backend_decl;

  /* If use associated and whole file compilation, use the module
     declaration.  This is only needed for intrinsic types because
     they are substituted for one another during optimization.  */
  if (gfc_option.flag_whole_file
        && sym->attr.flavor == FL_VARIABLE
        && sym->ts.type != BT_DERIVED
        && sym->attr.use_assoc
        && sym->module)
    {
      gfc_gsymbol *gsym;

      gsym =  gfc_find_gsymbol (gfc_gsym_root, sym->module);
      if (gsym && gsym->ns && gsym->type == GSYM_MODULE)
        {
          gfc_symbol *s;
          s = NULL;
          gfc_find_symbol (sym->name, gsym->ns, 0, &s);
          if (s && s->backend_decl)
            {
              if (sym->ts.type == BT_CHARACTER)
                sym->ts.u.cl->backend_decl = s->ts.u.cl->backend_decl;
              return s->backend_decl;
            }
        }
    }

  /* Catch function declarations.  Only used for actual parameters and
     procedure pointers.  */
  if (sym->attr.flavor == FL_PROCEDURE)
    {
      decl = gfc_get_extern_function_decl (sym);
      gfc_set_decl_location (decl, &sym->declared_at);
      return decl;
    }

  if (sym->attr.intrinsic)
    internal_error ("intrinsic variable which isn't a procedure");

  /* Create string length decl first so that they can be used in the
     type declaration.  */
  if (sym->ts.type == BT_CHARACTER)
    length = gfc_create_string_length (sym);

  /* Create the decl for the variable.  */
  decl = build_decl (sym->declared_at.lb->location,
                     VAR_DECL, gfc_sym_identifier (sym), gfc_sym_type (sym));

  /* Add attributes to variables.  Functions are handled elsewhere.  */
  attributes = add_attributes_to_decl (sym->attr, NULL_TREE);
  decl_attributes (&decl, attributes, 0);

  /* Symbols from modules should have their assembler names mangled.
     This is done here rather than in gfc_finish_var_decl because it
     is different for string length variables.  */
  if (sym->module)
    {
      gfc_set_decl_assembler_name (decl, gfc_sym_mangled_identifier (sym));
      if (sym->attr.use_assoc)
        DECL_IGNORED_P (decl) = 1;
    }

  if (sym->attr.dimension)
    {
      /* Create variables to hold the non-constant bits of array info.  */
      gfc_build_qualified_array (decl, sym);

      if ((sym->attr.allocatable || !sym->attr.dummy) && !sym->attr.pointer)
        GFC_DECL_PACKED_ARRAY (decl) = 1;
    }

  /* Remember this variable for allocation/cleanup.  */
  if (sym->attr.dimension || sym->attr.allocatable
      || (sym->ts.type == BT_CLASS &&
          (CLASS_DATA (sym)->attr.dimension
           || CLASS_DATA (sym)->attr.allocatable))
      || (sym->ts.type == BT_DERIVED && sym->ts.u.derived->attr.alloc_comp)
      /* This applies a derived type default initializer.  */
      || (sym->ts.type == BT_DERIVED
          && sym->attr.save == SAVE_NONE
          && !sym->attr.data
          && !sym->attr.allocatable
          && (sym->value && !sym->ns->proc_name->attr.is_main_program)
          && !sym->attr.use_assoc))
    gfc_defer_symbol_init (sym);

  gfc_finish_var_decl (decl, sym);

  if (sym->ts.type == BT_CHARACTER)
    {
      /* Character variables need special handling.  */
      gfc_allocate_lang_decl (decl);

      if (TREE_CODE (length) != INTEGER_CST)
        {
          char name[GFC_MAX_MANGLED_SYMBOL_LEN + 2];

          if (sym->module)
            {
              /* Also prefix the mangled name for symbols from modules.  */
              strcpy (&name[1], sym->name);
              name[0] = '.';
              strcpy (&name[1],
                      IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (length)));
              gfc_set_decl_assembler_name (decl, get_identifier (name));
            }
          gfc_finish_var_decl (length, sym);
          gcc_assert (!sym->value);
        }
    }
  else if (sym->attr.subref_array_pointer)
    {
      /* We need the span for these beasts.  */
      gfc_allocate_lang_decl (decl);
    }

  if (sym->attr.subref_array_pointer)
    {
      tree span;
      GFC_DECL_SUBREF_ARRAY_P (decl) = 1;
      span = build_decl (input_location,
                         VAR_DECL, create_tmp_var_name ("span"),
                         gfc_array_index_type);
      gfc_finish_var_decl (span, sym);
      TREE_STATIC (span) = TREE_STATIC (decl);
      DECL_ARTIFICIAL (span) = 1;
      DECL_INITIAL (span) = build_int_cst (gfc_array_index_type, 0);

      GFC_DECL_SPAN (decl) = span;
      GFC_TYPE_ARRAY_SPAN (TREE_TYPE (decl)) = span;
    }

  sym->backend_decl = decl;

  if (sym->attr.assign)
    gfc_add_assign_aux_vars (sym);

  if (TREE_STATIC (decl) && !sym->attr.use_assoc
      && (sym->attr.save || sym->ns->proc_name->attr.is_main_program
          || gfc_option.flag_max_stack_var_size == 0
          || sym->attr.data || sym->ns->proc_name->attr.flavor == FL_MODULE))
    {
      /* Add static initializer. For procedures, it is only needed if
         SAVE is specified otherwise they need to be reinitialized
         every time the procedure is entered. The TREE_STATIC is
         in this case due to -fmax-stack-var-size=.  */
      DECL_INITIAL (decl) = gfc_conv_initializer (sym->value, &sym->ts,
          TREE_TYPE (decl), sym->attr.dimension,
          sym->attr.pointer || sym->attr.allocatable);
    }

  if (!TREE_STATIC (decl)
      && POINTER_TYPE_P (TREE_TYPE (decl))
      && !sym->attr.pointer
      && !sym->attr.allocatable
      && !sym->attr.proc_pointer)
    DECL_BY_REFERENCE (decl) = 1;

  return decl;
}


/* Substitute a temporary variable in place of the real one.  */

void
gfc_shadow_sym (gfc_symbol * sym, tree decl, gfc_saved_var * save)
{
  save->attr = sym->attr;
  save->decl = sym->backend_decl;

  gfc_clear_attr (&sym->attr);
  sym->attr.referenced = 1;
  sym->attr.flavor = FL_VARIABLE;

  sym->backend_decl = decl;
}


/* Restore the original variable.  */

void
gfc_restore_sym (gfc_symbol * sym, gfc_saved_var * save)
{
  sym->attr = save->attr;
  sym->backend_decl = save->decl;
}


/* Declare a procedure pointer.  */

static tree
get_proc_pointer_decl (gfc_symbol *sym)
{
  tree decl;
  tree attributes;

  decl = sym->backend_decl;
  if (decl)
    return decl;

  decl = build_decl (input_location,
                     VAR_DECL, get_identifier (sym->name),
                     build_pointer_type (gfc_get_function_type (sym)));

  if ((sym->ns->proc_name
      && sym->ns->proc_name->backend_decl == current_function_decl)
      || sym->attr.contained)
    gfc_add_decl_to_function (decl);
  else if (sym->ns->proc_name->attr.flavor != FL_MODULE)
    gfc_add_decl_to_parent_function (decl);

  sym->backend_decl = decl;

  /* If a variable is USE associated, it's always external.  */
  if (sym->attr.use_assoc)
    {
      DECL_EXTERNAL (decl) = 1;
      TREE_PUBLIC (decl) = 1;
    }
  else if (sym->module && sym->ns->proc_name->attr.flavor == FL_MODULE)
    {
      /* This is the declaration of a module variable.  */
      TREE_PUBLIC (decl) = 1;
      TREE_STATIC (decl) = 1;
    }

  if (!sym->attr.use_assoc
        && (sym->attr.save != SAVE_NONE || sym->attr.data
              || (sym->value && sym->ns->proc_name->attr.is_main_program)))
    TREE_STATIC (decl) = 1;

  if (TREE_STATIC (decl) && sym->value)
    {
      /* Add static initializer.  */
      DECL_INITIAL (decl) = gfc_conv_initializer (sym->value, &sym->ts,
          TREE_TYPE (decl),
          sym->attr.proc_pointer ? false : sym->attr.dimension,
          sym->attr.proc_pointer);
    }

  attributes = add_attributes_to_decl (sym->attr, NULL_TREE);
  decl_attributes (&decl, attributes, 0);

  return decl;
}


/* Get a basic decl for an external function.  */

tree
gfc_get_extern_function_decl (gfc_symbol * sym)
{
  tree type;
  tree fndecl;
  tree attributes;
  gfc_expr e;
  gfc_intrinsic_sym *isym;
  gfc_expr argexpr;
  char s[GFC_MAX_SYMBOL_LEN + 23]; /* "_gfortran_f2c_specific" and '\0'.  */
  tree name;
  tree mangled_name;
  gfc_gsymbol *gsym;

  if (sym->backend_decl)
    return sym->backend_decl;

  /* We should never be creating external decls for alternate entry points.
     The procedure may be an alternate entry point, but we don't want/need
     to know that.  */
  gcc_assert (!(sym->attr.entry || sym->attr.entry_master));

  if (sym->attr.proc_pointer)
    return get_proc_pointer_decl (sym);

  /* See if this is an external procedure from the same file.  If so,
     return the backend_decl.  */
  gsym =  gfc_find_gsymbol (gfc_gsym_root, sym->name);

  if (gfc_option.flag_whole_file
        && !sym->attr.use_assoc
        && !sym->backend_decl
        && gsym && gsym->ns
        && ((gsym->type == GSYM_SUBROUTINE) || (gsym->type == GSYM_FUNCTION))
        && gsym->ns->proc_name->backend_decl)
    {
      /* If the namespace has entries, the proc_name is the
         entry master.  Find the entry and use its backend_decl.
         otherwise, use the proc_name backend_decl.  */
      if (gsym->ns->entries)
        {
          gfc_entry_list *entry = gsym->ns->entries;

          for (; entry; entry = entry->next)
            {
              if (strcmp (gsym->name, entry->sym->name) == 0)
                {
                  sym->backend_decl = entry->sym->backend_decl;
                  break;
                }
            }
        }
      else
        {
          sym->backend_decl = gsym->ns->proc_name->backend_decl;
        }

      if (sym->backend_decl)
        return sym->backend_decl;
    }

  /* See if this is a module procedure from the same file.  If so,
     return the backend_decl.  */
  if (sym->module)
    gsym =  gfc_find_gsymbol (gfc_gsym_root, sym->module);

  if (gfc_option.flag_whole_file
        && gsym && gsym->ns
        && gsym->type == GSYM_MODULE)
    {
      gfc_symbol *s;

      s = NULL;
      gfc_find_symbol (sym->name, gsym->ns, 0, &s);
      if (s && s->backend_decl)
        {
          sym->backend_decl = s->backend_decl;
          return sym->backend_decl;
        }
    }

  if (sym->attr.intrinsic)
    {
      /* Call the resolution function to get the actual name.  This is
         a nasty hack which relies on the resolution functions only looking
         at the first argument.  We pass NULL for the second argument
         otherwise things like AINT get confused.  */
      isym = gfc_find_function (sym->name);
      gcc_assert (isym->resolve.f0 != NULL);

      memset (&e, 0, sizeof (e));
      e.expr_type = EXPR_FUNCTION;

      memset (&argexpr, 0, sizeof (argexpr));
      gcc_assert (isym->formal);
      argexpr.ts = isym->formal->ts;

      if (isym->formal->next == NULL)
        isym->resolve.f1 (&e, &argexpr);
      else
        {
          if (isym->formal->next->next == NULL)
            isym->resolve.f2 (&e, &argexpr, NULL);
          else
            {
              if (isym->formal->next->next->next == NULL)
                isym->resolve.f3 (&e, &argexpr, NULL, NULL);
              else
                {
                  /* All specific intrinsics take less than 5 arguments.  */
                  gcc_assert (isym->formal->next->next->next->next == NULL);
                  isym->resolve.f4 (&e, &argexpr, NULL, NULL, NULL);
                }
            }
        }

      if (gfc_option.flag_f2c
          && ((e.ts.type == BT_REAL && e.ts.kind == gfc_default_real_kind)
              || e.ts.type == BT_COMPLEX))
        {
          /* Specific which needs a different implementation if f2c
             calling conventions are used.  */
          sprintf (s, "_gfortran_f2c_specific%s", e.value.function.name);
        }
      else
        sprintf (s, "_gfortran_specific%s", e.value.function.name);

      name = get_identifier (s);
      mangled_name = name;
    }
  else
    {
      name = gfc_sym_identifier (sym);
      mangled_name = gfc_sym_mangled_function_id (sym);
    }

  type = gfc_get_function_type (sym);
  fndecl = build_decl (input_location,
                       FUNCTION_DECL, name, type);

  attributes = add_attributes_to_decl (sym->attr, NULL_TREE);
  decl_attributes (&fndecl, attributes, 0);

  gfc_set_decl_assembler_name (fndecl, mangled_name);

  /* Set the context of this decl.  */
  if (0 && sym->ns && sym->ns->proc_name)
    {
      /* TODO: Add external decls to the appropriate scope.  */
      DECL_CONTEXT (fndecl) = sym->ns->proc_name->backend_decl;
    }
  else
    {
      /* Global declaration, e.g. intrinsic subroutine.  */
      DECL_CONTEXT (fndecl) = NULL_TREE;
    }

  DECL_EXTERNAL (fndecl) = 1;

  /* This specifies if a function is globally addressable, i.e. it is
     the opposite of declaring static in C.  */
  TREE_PUBLIC (fndecl) = 1;

  /* Set attributes for PURE functions. A call to PURE function in the
     Fortran 95 sense is both pure and without side effects in the C
     sense.  */
  if (sym->attr.pure || sym->attr.elemental)
    {
      if (sym->attr.function && !gfc_return_by_reference (sym))
        DECL_PURE_P (fndecl) = 1;
      /* TODO: check if pure SUBROUTINEs don't have INTENT(OUT)
         parameters and don't use alternate returns (is this
         allowed?). In that case, calls to them are meaningless, and
         can be optimized away. See also in build_function_decl().  */
      TREE_SIDE_EFFECTS (fndecl) = 0;
    }

  /* Mark non-returning functions.  */
  if (sym->attr.noreturn)
      TREE_THIS_VOLATILE(fndecl) = 1;

  sym->backend_decl = fndecl;

  if (DECL_CONTEXT (fndecl) == NULL_TREE)
    pushdecl_top_level (fndecl);

  return fndecl;
}


/* Create a declaration for a procedure.  For external functions (in the C
   sense) use gfc_get_extern_function_decl.  HAS_ENTRIES is true if this is
   a master function with alternate entry points.  */

static void
build_function_decl (gfc_symbol * sym)
{
  tree fndecl, type, attributes;
  symbol_attribute attr;
  tree result_decl;
  gfc_formal_arglist *f;

  gcc_assert (!sym->backend_decl);
  gcc_assert (!sym->attr.external);

  /* Set the line and filename.  sym->declared_at seems to point to the
     last statement for subroutines, but it'll do for now.  */
  gfc_set_backend_locus (&sym->declared_at);

  /* Allow only one nesting level.  Allow public declarations.  */
  gcc_assert (current_function_decl == NULL_TREE
              || DECL_CONTEXT (current_function_decl) == NULL_TREE
              || TREE_CODE (DECL_CONTEXT (current_function_decl))
                 == NAMESPACE_DECL);

  type = gfc_get_function_type (sym);
  fndecl = build_decl (input_location,
                       FUNCTION_DECL, gfc_sym_identifier (sym), type);

  attr = sym->attr;

  attributes = add_attributes_to_decl (attr, NULL_TREE);
  decl_attributes (&fndecl, attributes, 0);

  /* Perform name mangling if this is a top level or module procedure.  */
  if (current_function_decl == NULL_TREE)
    gfc_set_decl_assembler_name (fndecl, gfc_sym_mangled_function_id (sym));

  /* Figure out the return type of the declared function, and build a
     RESULT_DECL for it.  If this is a subroutine with alternate
     returns, build a RESULT_DECL for it.  */
  result_decl = NULL_TREE;
  /* TODO: Shouldn't this just be TREE_TYPE (TREE_TYPE (fndecl)).  */
  if (attr.function)
    {
      if (gfc_return_by_reference (sym))
        type = void_type_node;
      else
        {
          if (sym->result != sym)
            result_decl = gfc_sym_identifier (sym->result);

          type = TREE_TYPE (TREE_TYPE (fndecl));
        }
    }
  else
    {
      /* Look for alternate return placeholders.  */
      int has_alternate_returns = 0;
      for (f = sym->formal; f; f = f->next)
        {
          if (f->sym == NULL)
            {
              has_alternate_returns = 1;
              break;
            }
        }

      if (has_alternate_returns)
        type = integer_type_node;
      else
        type = void_type_node;
    }

  result_decl = build_decl (input_location,
                            RESULT_DECL, result_decl, type);
  DECL_ARTIFICIAL (result_decl) = 1;
  DECL_IGNORED_P (result_decl) = 1;
  DECL_CONTEXT (result_decl) = fndecl;
  DECL_RESULT (fndecl) = result_decl;

  /* Don't call layout_decl for a RESULT_DECL.
     layout_decl (result_decl, 0);  */

  /* Set up all attributes for the function.  */
  DECL_CONTEXT (fndecl) = current_function_decl;
  DECL_EXTERNAL (fndecl) = 0;

  /* This specifies if a function is globally visible, i.e. it is
     the opposite of declaring static in C.  */
  if (DECL_CONTEXT (fndecl) == NULL_TREE
      && !sym->attr.entry_master && !sym->attr.is_main_program)
    TREE_PUBLIC (fndecl) = 1;

  /* TREE_STATIC means the function body is defined here.  */
  TREE_STATIC (fndecl) = 1;

  /* Set attributes for PURE functions. A call to a PURE function in the
     Fortran 95 sense is both pure and without side effects in the C
     sense.  */
  if (attr.pure || attr.elemental)
    {
      /* TODO: check if a pure SUBROUTINE has no INTENT(OUT) arguments
         including an alternate return. In that case it can also be
         marked as PURE. See also in gfc_get_extern_function_decl().  */
      if (attr.function && !gfc_return_by_reference (sym))
        DECL_PURE_P (fndecl) = 1;
      TREE_SIDE_EFFECTS (fndecl) = 0;
    }


  /* Layout the function declaration and put it in the binding level
     of the current function.  */
  pushdecl (fndecl);

  sym->backend_decl = fndecl;
}


/* Create the DECL_ARGUMENTS for a procedure.  */

static void
create_function_arglist (gfc_symbol * sym)
{
  tree fndecl;
  gfc_formal_arglist *f;
  tree typelist, hidden_typelist;
  tree arglist, hidden_arglist;
  tree type;
  tree parm;

  fndecl = sym->backend_decl;

  /* Build formal argument list. Make sure that their TREE_CONTEXT is
     the new FUNCTION_DECL node.  */
  arglist = NULL_TREE;
  hidden_arglist = NULL_TREE;
  typelist = TYPE_ARG_TYPES (TREE_TYPE (fndecl));

  if (sym->attr.entry_master)
    {
      type = TREE_VALUE (typelist);
      parm = build_decl (input_location,
                         PARM_DECL, get_identifier ("__entry"), type);
      
      DECL_CONTEXT (parm) = fndecl;
      DECL_ARG_TYPE (parm) = type;
      TREE_READONLY (parm) = 1;
      gfc_finish_decl (parm);
      DECL_ARTIFICIAL (parm) = 1;

      arglist = chainon (arglist, parm);
      typelist = TREE_CHAIN (typelist);
    }

  if (gfc_return_by_reference (sym))
    {
      tree type = TREE_VALUE (typelist), length = NULL;

      if (sym->ts.type == BT_CHARACTER)
        {
          /* Length of character result.  */
          tree len_type = TREE_VALUE (TREE_CHAIN (typelist));
          gcc_assert (len_type == gfc_charlen_type_node);

          length = build_decl (input_location,
                               PARM_DECL,
                               get_identifier (".__result"),
                               len_type);
          if (!sym->ts.u.cl->length)
            {
              sym->ts.u.cl->backend_decl = length;
              TREE_USED (length) = 1;
            }
          gcc_assert (TREE_CODE (length) == PARM_DECL);
          DECL_CONTEXT (length) = fndecl;
          DECL_ARG_TYPE (length) = len_type;
          TREE_READONLY (length) = 1;
          DECL_ARTIFICIAL (length) = 1;
          gfc_finish_decl (length);
          if (sym->ts.u.cl->backend_decl == NULL
              || sym->ts.u.cl->backend_decl == length)
            {
              gfc_symbol *arg;
              tree backend_decl;

              if (sym->ts.u.cl->backend_decl == NULL)
                {
                  tree len = build_decl (input_location,
                                         VAR_DECL,
                                         get_identifier ("..__result"),
                                         gfc_charlen_type_node);
                  DECL_ARTIFICIAL (len) = 1;
                  TREE_USED (len) = 1;
                  sym->ts.u.cl->backend_decl = len;
                }

              /* Make sure PARM_DECL type doesn't point to incomplete type.  */
              arg = sym->result ? sym->result : sym;
              backend_decl = arg->backend_decl;
              /* Temporary clear it, so that gfc_sym_type creates complete
                 type.  */
              arg->backend_decl = NULL;
              type = gfc_sym_type (arg);
              arg->backend_decl = backend_decl;
              type = build_reference_type (type);
            }
        }

      parm = build_decl (input_location,
                         PARM_DECL, get_identifier ("__result"), type);

      DECL_CONTEXT (parm) = fndecl;
      DECL_ARG_TYPE (parm) = TREE_VALUE (typelist);
      TREE_READONLY (parm) = 1;
      DECL_ARTIFICIAL (parm) = 1;
      gfc_finish_decl (parm);

      arglist = chainon (arglist, parm);
      typelist = TREE_CHAIN (typelist);

      if (sym->ts.type == BT_CHARACTER)
        {
          gfc_allocate_lang_decl (parm);
          arglist = chainon (arglist, length);
          typelist = TREE_CHAIN (typelist);
        }
    }

  hidden_typelist = typelist;
  for (f = sym->formal; f; f = f->next)
    if (f->sym != NULL) /* Ignore alternate returns.  */
      hidden_typelist = TREE_CHAIN (hidden_typelist);

  for (f = sym->formal; f; f = f->next)
    {
      char name[GFC_MAX_SYMBOL_LEN + 2];

      /* Ignore alternate returns.  */
      if (f->sym == NULL)
        continue;

      type = TREE_VALUE (typelist);

      if (f->sym->ts.type == BT_CHARACTER
          && (!sym->attr.is_bind_c || sym->attr.entry_master))
        {
          tree len_type = TREE_VALUE (hidden_typelist);
          tree length = NULL_TREE;
          gcc_assert (len_type == gfc_charlen_type_node);

          strcpy (&name[1], f->sym->name);
          name[0] = '_';
          length = build_decl (input_location,
                               PARM_DECL, get_identifier (name), len_type);

          hidden_arglist = chainon (hidden_arglist, length);
          DECL_CONTEXT (length) = fndecl;
          DECL_ARTIFICIAL (length) = 1;
          DECL_ARG_TYPE (length) = len_type;
          TREE_READONLY (length) = 1;
          gfc_finish_decl (length);

          /* Remember the passed value.  */
          if (f->sym->ts.u.cl->passed_length != NULL)
            {
              /* This can happen if the same type is used for multiple
                 arguments. We need to copy cl as otherwise
                 cl->passed_length gets overwritten.  */
              f->sym->ts.u.cl = gfc_new_charlen (f->sym->ns, f->sym->ts.u.cl);
            }
          f->sym->ts.u.cl->passed_length = length;

          /* Use the passed value for assumed length variables.  */
          if (!f->sym->ts.u.cl->length)
            {
              TREE_USED (length) = 1;
              gcc_assert (!f->sym->ts.u.cl->backend_decl);
              f->sym->ts.u.cl->backend_decl = length;
            }

          hidden_typelist = TREE_CHAIN (hidden_typelist);

          if (f->sym->ts.u.cl->backend_decl == NULL
              || f->sym->ts.u.cl->backend_decl == length)
            {
              if (f->sym->ts.u.cl->backend_decl == NULL)
                gfc_create_string_length (f->sym);

              /* Make sure PARM_DECL type doesn't point to incomplete type.  */
              if (f->sym->attr.flavor == FL_PROCEDURE)
                type = build_pointer_type (gfc_get_function_type (f->sym));
              else
                type = gfc_sym_type (f->sym);
            }
        }

      /* For non-constant length array arguments, make sure they use
         a different type node from TYPE_ARG_TYPES type.  */
      if (f->sym->attr.dimension
          && type == TREE_VALUE (typelist)
          && TREE_CODE (type) == POINTER_TYPE
          && GFC_ARRAY_TYPE_P (type)
          && f->sym->as->type != AS_ASSUMED_SIZE
          && ! COMPLETE_TYPE_P (TREE_TYPE (type)))
        {
          if (f->sym->attr.flavor == FL_PROCEDURE)
            type = build_pointer_type (gfc_get_function_type (f->sym));
          else
            type = gfc_sym_type (f->sym);
        }

      if (f->sym->attr.proc_pointer)
        type = build_pointer_type (type);

      /* Build the argument declaration.  */
      parm = build_decl (input_location,
                         PARM_DECL, gfc_sym_identifier (f->sym), type);

      /* Fill in arg stuff.  */
      DECL_CONTEXT (parm) = fndecl;
      DECL_ARG_TYPE (parm) = TREE_VALUE (typelist);
      /* All implementation args are read-only.  */
      TREE_READONLY (parm) = 1;
      if (POINTER_TYPE_P (type)
          && (!f->sym->attr.proc_pointer
              && f->sym->attr.flavor != FL_PROCEDURE))
        DECL_BY_REFERENCE (parm) = 1;

      gfc_finish_decl (parm);

      f->sym->backend_decl = parm;

      arglist = chainon (arglist, parm);
      typelist = TREE_CHAIN (typelist);
    }

  /* Add the hidden string length parameters, unless the procedure
     is bind(C).  */
  if (!sym->attr.is_bind_c)
    arglist = chainon (arglist, hidden_arglist);

  gcc_assert (hidden_typelist == NULL_TREE
              || TREE_VALUE (hidden_typelist) == void_type_node);
  DECL_ARGUMENTS (fndecl) = arglist;
}

/* Do the setup necessary before generating the body of a function.  */

static void
trans_function_start (gfc_symbol * sym)
{
  tree fndecl;

  fndecl = sym->backend_decl;

  /* Let GCC know the current scope is this function.  */
  current_function_decl = fndecl;

  /* Let the world know what we're about to do.  */
  announce_function (fndecl);

  if (DECL_CONTEXT (fndecl) == NULL_TREE)
    {
      /* Create RTL for function declaration.  */
      rest_of_decl_compilation (fndecl, 1, 0);
    }

  /* Create RTL for function definition.  */
  make_decl_rtl (fndecl);

  init_function_start (fndecl);

  /* Even though we're inside a function body, we still don't want to
     call expand_expr to calculate the size of a variable-sized array.
     We haven't necessarily assigned RTL to all variables yet, so it's
     not safe to try to expand expressions involving them.  */
  cfun->dont_save_pending_sizes_p = 1;

  /* function.c requires a push at the start of the function.  */
  pushlevel (0);
}

/* Create thunks for alternate entry points.  */

static void
build_entry_thunks (gfc_namespace * ns)
{
  gfc_formal_arglist *formal;
  gfc_formal_arglist *thunk_formal;
  gfc_entry_list *el;
  gfc_symbol *thunk_sym;
  stmtblock_t body;
  tree thunk_fndecl;
  tree args;
  tree string_args;
  tree tmp;
  locus old_loc;

  /* This should always be a toplevel function.  */
  gcc_assert (current_function_decl == NULL_TREE);

  gfc_get_backend_locus (&old_loc);
  for (el = ns->entries; el; el = el->next)
    {
      thunk_sym = el->sym;
      
      build_function_decl (thunk_sym);
      create_function_arglist (thunk_sym);

      trans_function_start (thunk_sym);

      thunk_fndecl = thunk_sym->backend_decl;

      gfc_init_block (&body);

      /* Pass extra parameter identifying this entry point.  */
      tmp = build_int_cst (gfc_array_index_type, el->id);
      args = tree_cons (NULL_TREE, tmp, NULL_TREE);
      string_args = NULL_TREE;

      if (thunk_sym->attr.function)
        {
          if (gfc_return_by_reference (ns->proc_name))
            {
              tree ref = DECL_ARGUMENTS (current_function_decl);
              args = tree_cons (NULL_TREE, ref, args);
              if (ns->proc_name->ts.type == BT_CHARACTER)
                args = tree_cons (NULL_TREE, TREE_CHAIN (ref),
                                  args);
            }
        }

      for (formal = ns->proc_name->formal; formal; formal = formal->next)
        {
          /* Ignore alternate returns.  */
          if (formal->sym == NULL)
            continue;

          /* We don't have a clever way of identifying arguments, so resort to
             a brute-force search.  */
          for (thunk_formal = thunk_sym->formal;
               thunk_formal;
               thunk_formal = thunk_formal->next)
            {
              if (thunk_formal->sym == formal->sym)
                break;
            }

          if (thunk_formal)
            {
              /* Pass the argument.  */
              DECL_ARTIFICIAL (thunk_formal->sym->backend_decl) = 1;
              args = tree_cons (NULL_TREE, thunk_formal->sym->backend_decl,
                                args);
              if (formal->sym->ts.type == BT_CHARACTER)
                {
                  tmp = thunk_formal->sym->ts.u.cl->backend_decl;
                  string_args = tree_cons (NULL_TREE, tmp, string_args);
                }
            }
          else
            {
              /* Pass NULL for a missing argument.  */
              args = tree_cons (NULL_TREE, null_pointer_node, args);
              if (formal->sym->ts.type == BT_CHARACTER)
                {
                  tmp = build_int_cst (gfc_charlen_type_node, 0);
                  string_args = tree_cons (NULL_TREE, tmp, string_args);
                }
            }
        }

      /* Call the master function.  */
      args = nreverse (args);
      args = chainon (args, nreverse (string_args));
      tmp = ns->proc_name->backend_decl;
      tmp = build_function_call_expr (input_location, tmp, args);
      if (ns->proc_name->attr.mixed_entry_master)
        {
          tree union_decl, field;
          tree master_type = TREE_TYPE (ns->proc_name->backend_decl);

          union_decl = build_decl (input_location,
                                   VAR_DECL, get_identifier ("__result"),
                                   TREE_TYPE (master_type));
          DECL_ARTIFICIAL (union_decl) = 1;
          DECL_EXTERNAL (union_decl) = 0;
          TREE_PUBLIC (union_decl) = 0;
          TREE_USED (union_decl) = 1;
          layout_decl (union_decl, 0);
          pushdecl (union_decl);

          DECL_CONTEXT (union_decl) = current_function_decl;
          tmp = fold_build2 (MODIFY_EXPR, TREE_TYPE (union_decl),
                             union_decl, tmp);
          gfc_add_expr_to_block (&body, tmp);

          for (field = TYPE_FIELDS (TREE_TYPE (union_decl));
               field; field = TREE_CHAIN (field))
            if (strcmp (IDENTIFIER_POINTER (DECL_NAME (field)),
                thunk_sym->result->name) == 0)
              break;
          gcc_assert (field != NULL_TREE);
          tmp = fold_build3 (COMPONENT_REF, TREE_TYPE (field),
                             union_decl, field, NULL_TREE);
          tmp = fold_build2 (MODIFY_EXPR, 
                             TREE_TYPE (DECL_RESULT (current_function_decl)),
                             DECL_RESULT (current_function_decl), tmp);
          tmp = build1_v (RETURN_EXPR, tmp);
        }
      else if (TREE_TYPE (DECL_RESULT (current_function_decl))
               != void_type_node)
        {
          tmp = fold_build2 (MODIFY_EXPR,
                             TREE_TYPE (DECL_RESULT (current_function_decl)),
                             DECL_RESULT (current_function_decl), tmp);
          tmp = build1_v (RETURN_EXPR, tmp);
        }
      gfc_add_expr_to_block (&body, tmp);

      /* Finish off this function and send it for code generation.  */
      DECL_SAVED_TREE (thunk_fndecl) = gfc_finish_block (&body);
      tmp = getdecls ();
      poplevel (1, 0, 1);
      BLOCK_SUPERCONTEXT (DECL_INITIAL (thunk_fndecl)) = thunk_fndecl;
      DECL_SAVED_TREE (thunk_fndecl)
        = build3_v (BIND_EXPR, tmp, DECL_SAVED_TREE (thunk_fndecl),
                    DECL_INITIAL (thunk_fndecl));

      /* Output the GENERIC tree.  */
      dump_function (TDI_original, thunk_fndecl);

      /* Store the end of the function, so that we get good line number
         info for the epilogue.  */
      cfun->function_end_locus = input_location;

      /* We're leaving the context of this function, so zap cfun.
         It's still in DECL_STRUCT_FUNCTION, and we'll restore it in
         tree_rest_of_compilation.  */
      set_cfun (NULL);

      current_function_decl = NULL_TREE;

      cgraph_finalize_function (thunk_fndecl, true);

      /* We share the symbols in the formal argument list with other entry
         points and the master function.  Clear them so that they are
         recreated for each function.  */
      for (formal = thunk_sym->formal; formal; formal = formal->next)
        if (formal->sym != NULL)  /* Ignore alternate returns.  */
          {
            formal->sym->backend_decl = NULL_TREE;
            if (formal->sym->ts.type == BT_CHARACTER)
              formal->sym->ts.u.cl->backend_decl = NULL_TREE;
          }

      if (thunk_sym->attr.function)
        {
          if (thunk_sym->ts.type == BT_CHARACTER)
            thunk_sym->ts.u.cl->backend_decl = NULL_TREE;
          if (thunk_sym->result->ts.type == BT_CHARACTER)
            thunk_sym->result->ts.u.cl->backend_decl = NULL_TREE;
        }
    }

  gfc_set_backend_locus (&old_loc);
}


/* Create a decl for a function, and create any thunks for alternate entry
   points.  */

void
gfc_create_function_decl (gfc_namespace * ns)
{
  /* Create a declaration for the master function.  */
  build_function_decl (ns->proc_name);

  /* Compile the entry thunks.  */
  if (ns->entries)
    build_entry_thunks (ns);

  /* Now create the read argument list.  */
  create_function_arglist (ns->proc_name);
}

/* Return the decl used to hold the function return value.  If
   parent_flag is set, the context is the parent_scope.  */

tree
gfc_get_fake_result_decl (gfc_symbol * sym, int parent_flag)
{
  tree decl;
  tree length;
  tree this_fake_result_decl;
  tree this_function_decl;

  char name[GFC_MAX_SYMBOL_LEN + 10];

  if (parent_flag)
    {
      this_fake_result_decl = parent_fake_result_decl;
      this_function_decl = DECL_CONTEXT (current_function_decl);
    }
  else
    {
      this_fake_result_decl = current_fake_result_decl;
      this_function_decl = current_function_decl;
    }

  if (sym
      && sym->ns->proc_name->backend_decl == this_function_decl
      && sym->ns->proc_name->attr.entry_master
      && sym != sym->ns->proc_name)
    {
      tree t = NULL, var;
      if (this_fake_result_decl != NULL)
        for (t = TREE_CHAIN (this_fake_result_decl); t; t = TREE_CHAIN (t))
          if (strcmp (IDENTIFIER_POINTER (TREE_PURPOSE (t)), sym->name) == 0)
            break;
      if (t)
        return TREE_VALUE (t);
      decl = gfc_get_fake_result_decl (sym->ns->proc_name, parent_flag);

      if (parent_flag)
        this_fake_result_decl = parent_fake_result_decl;
      else
        this_fake_result_decl = current_fake_result_decl;

      if (decl && sym->ns->proc_name->attr.mixed_entry_master)
        {
          tree field;

          for (field = TYPE_FIELDS (TREE_TYPE (decl));
               field; field = TREE_CHAIN (field))
            if (strcmp (IDENTIFIER_POINTER (DECL_NAME (field)),
                sym->name) == 0)
              break;

          gcc_assert (field != NULL_TREE);
          decl = fold_build3 (COMPONENT_REF, TREE_TYPE (field),
                              decl, field, NULL_TREE);
        }

      var = create_tmp_var_raw (TREE_TYPE (decl), sym->name);
      if (parent_flag)
        gfc_add_decl_to_parent_function (var);
      else
        gfc_add_decl_to_function (var);

      SET_DECL_VALUE_EXPR (var, decl);
      DECL_HAS_VALUE_EXPR_P (var) = 1;
      GFC_DECL_RESULT (var) = 1;

      TREE_CHAIN (this_fake_result_decl)
          = tree_cons (get_identifier (sym->name), var,
                       TREE_CHAIN (this_fake_result_decl));
      return var;
    }

  if (this_fake_result_decl != NULL_TREE)
    return TREE_VALUE (this_fake_result_decl);

  /* Only when gfc_get_fake_result_decl is called by gfc_trans_return,
     sym is NULL.  */
  if (!sym)
    return NULL_TREE;

  if (sym->ts.type == BT_CHARACTER)
    {
      if (sym->ts.u.cl->backend_decl == NULL_TREE)
        length = gfc_create_string_length (sym);
      else
        length = sym->ts.u.cl->backend_decl;
      if (TREE_CODE (length) == VAR_DECL
          && DECL_CONTEXT (length) == NULL_TREE)
        gfc_add_decl_to_function (length);
    }

  if (gfc_return_by_reference (sym))
    {
      decl = DECL_ARGUMENTS (this_function_decl);

      if (sym->ns->proc_name->backend_decl == this_function_decl
          && sym->ns->proc_name->attr.entry_master)
        decl = TREE_CHAIN (decl);

      TREE_USED (decl) = 1;
      if (sym->as)
        decl = gfc_build_dummy_array_decl (sym, decl);
    }
  else
    {
      sprintf (name, "__result_%.20s",
               IDENTIFIER_POINTER (DECL_NAME (this_function_decl)));

      if (!sym->attr.mixed_entry_master && sym->attr.function)
        decl = build_decl (DECL_SOURCE_LOCATION (this_function_decl),
                           VAR_DECL, get_identifier (name),
                           gfc_sym_type (sym));
      else
        decl = build_decl (DECL_SOURCE_LOCATION (this_function_decl),
                           VAR_DECL, get_identifier (name),
                           TREE_TYPE (TREE_TYPE (this_function_decl)));
      DECL_ARTIFICIAL (decl) = 1;
      DECL_EXTERNAL (decl) = 0;
      TREE_PUBLIC (decl) = 0;
      TREE_USED (decl) = 1;
      GFC_DECL_RESULT (decl) = 1;
      TREE_ADDRESSABLE (decl) = 1;

      layout_decl (decl, 0);

      if (parent_flag)
        gfc_add_decl_to_parent_function (decl);
      else
        gfc_add_decl_to_function (decl);
    }

  if (parent_flag)
    parent_fake_result_decl = build_tree_list (NULL, decl);
  else
    current_fake_result_decl = build_tree_list (NULL, decl);

  return decl;
}


/* Builds a function decl.  The remaining parameters are the types of the
   function arguments.  Negative nargs indicates a varargs function.  */

static tree
build_library_function_decl_1 (tree name, const char *spec,
                               tree rettype, int nargs, va_list p)
{
  tree arglist;
  tree argtype;
  tree fntype;
  tree fndecl;
  int n;

  /* Library functions must be declared with global scope.  */
  gcc_assert (current_function_decl == NULL_TREE);

  /* Create a list of the argument types.  */
  for (arglist = NULL_TREE, n = abs (nargs); n > 0; n--)
    {
      argtype = va_arg (p, tree);
      arglist = gfc_chainon_list (arglist, argtype);
    }

  if (nargs >= 0)
    {
      /* Terminate the list.  */
      arglist = gfc_chainon_list (arglist, void_type_node);
    }

  /* Build the function type and decl.  */
  fntype = build_function_type (rettype, arglist);
  if (spec)
    {
      tree attr_args = build_tree_list (NULL_TREE,
                                        build_string (strlen (spec), spec));
      tree attrs = tree_cons (get_identifier ("fn spec"),
                              attr_args, TYPE_ATTRIBUTES (fntype));
      fntype = build_type_attribute_variant (fntype, attrs);
    }
  fndecl = build_decl (input_location,
                       FUNCTION_DECL, name, fntype);

  /* Mark this decl as external.  */
  DECL_EXTERNAL (fndecl) = 1;
  TREE_PUBLIC (fndecl) = 1;

  pushdecl (fndecl);

  rest_of_decl_compilation (fndecl, 1, 0);

  return fndecl;
}

/* Builds a function decl.  The remaining parameters are the types of the
   function arguments.  Negative nargs indicates a varargs function.  */

tree
gfc_build_library_function_decl (tree name, tree rettype, int nargs, ...)
{
  tree ret;
  va_list args;
  va_start (args, nargs);
  ret = build_library_function_decl_1 (name, NULL, rettype, nargs, args);
  va_end (args);
  return ret;
}

/* Builds a function decl.  The remaining parameters are the types of the
   function arguments.  Negative nargs indicates a varargs function.
   The SPEC parameter specifies the function argument and return type
   specification according to the fnspec function type attribute.  */

static tree
gfc_build_library_function_decl_with_spec (tree name, const char *spec,
                                           tree rettype, int nargs, ...)
{
  tree ret;
  va_list args;
  va_start (args, nargs);
  ret = build_library_function_decl_1 (name, spec, rettype, nargs, args);
  va_end (args);
  return ret;
}

static void
gfc_build_intrinsic_function_decls (void)
{
  tree gfc_int4_type_node = gfc_get_int_type (4);
  tree gfc_int8_type_node = gfc_get_int_type (8);
  tree gfc_int16_type_node = gfc_get_int_type (16);
  tree gfc_logical4_type_node = gfc_get_logical_type (4);
  tree pchar1_type_node = gfc_get_pchar_type (1);
  tree pchar4_type_node = gfc_get_pchar_type (4);

  /* String functions.  */
  gfor_fndecl_compare_string =
    gfc_build_library_function_decl (get_identifier (PREFIX("compare_string")),
                                     integer_type_node, 4,
                                     gfc_charlen_type_node, pchar1_type_node,
                                     gfc_charlen_type_node, pchar1_type_node);

  gfor_fndecl_concat_string =
    gfc_build_library_function_decl (get_identifier (PREFIX("concat_string")),
                                     void_type_node, 6,
                                     gfc_charlen_type_node, pchar1_type_node,
                                     gfc_charlen_type_node, pchar1_type_node,
                                     gfc_charlen_type_node, pchar1_type_node);

  gfor_fndecl_string_len_trim =
    gfc_build_library_function_decl (get_identifier (PREFIX("string_len_trim")),
                                     gfc_int4_type_node, 2,
                                     gfc_charlen_type_node, pchar1_type_node);

  gfor_fndecl_string_index =
    gfc_build_library_function_decl (get_identifier (PREFIX("string_index")),
                                     gfc_int4_type_node, 5,
                                     gfc_charlen_type_node, pchar1_type_node,
                                     gfc_charlen_type_node, pchar1_type_node,
                                     gfc_logical4_type_node);

  gfor_fndecl_string_scan =
    gfc_build_library_function_decl (get_identifier (PREFIX("string_scan")),
                                     gfc_int4_type_node, 5,
                                     gfc_charlen_type_node, pchar1_type_node,
                                     gfc_charlen_type_node, pchar1_type_node,
                                     gfc_logical4_type_node);

  gfor_fndecl_string_verify =
    gfc_build_library_function_decl (get_identifier (PREFIX("string_verify")),
                                     gfc_int4_type_node, 5,
                                     gfc_charlen_type_node, pchar1_type_node,
                                     gfc_charlen_type_node, pchar1_type_node,
                                     gfc_logical4_type_node);

  gfor_fndecl_string_trim =
    gfc_build_library_function_decl (get_identifier (PREFIX("string_trim")),
                                     void_type_node, 4,
                                     build_pointer_type (gfc_charlen_type_node),
                                     build_pointer_type (pchar1_type_node),
                                     gfc_charlen_type_node, pchar1_type_node);

  gfor_fndecl_string_minmax = 
    gfc_build_library_function_decl (get_identifier (PREFIX("string_minmax")),
                                     void_type_node, -4,
                                     build_pointer_type (gfc_charlen_type_node),
                                     build_pointer_type (pchar1_type_node),
                                     integer_type_node, integer_type_node);

  gfor_fndecl_adjustl =
    gfc_build_library_function_decl (get_identifier (PREFIX("adjustl")),
                                     void_type_node, 3, pchar1_type_node,
                                     gfc_charlen_type_node, pchar1_type_node);

  gfor_fndecl_adjustr =
    gfc_build_library_function_decl (get_identifier (PREFIX("adjustr")),
                                     void_type_node, 3, pchar1_type_node,
                                     gfc_charlen_type_node, pchar1_type_node);

  gfor_fndecl_select_string =
    gfc_build_library_function_decl (get_identifier (PREFIX("select_string")),
                                     integer_type_node, 4, pvoid_type_node,
                                     integer_type_node, pchar1_type_node,
                                     gfc_charlen_type_node);

  gfor_fndecl_compare_string_char4 =
    gfc_build_library_function_decl (get_identifier
                                        (PREFIX("compare_string_char4")),
                                     integer_type_node, 4,
                                     gfc_charlen_type_node, pchar4_type_node,
                                     gfc_charlen_type_node, pchar4_type_node);

  gfor_fndecl_concat_string_char4 =
    gfc_build_library_function_decl (get_identifier
                                        (PREFIX("concat_string_char4")),
                                     void_type_node, 6,
                                     gfc_charlen_type_node, pchar4_type_node,
                                     gfc_charlen_type_node, pchar4_type_node,
                                     gfc_charlen_type_node, pchar4_type_node);

  gfor_fndecl_string_len_trim_char4 =
    gfc_build_library_function_decl (get_identifier
                                        (PREFIX("string_len_trim_char4")),
                                     gfc_charlen_type_node, 2,
                                     gfc_charlen_type_node, pchar4_type_node);

  gfor_fndecl_string_index_char4 =
    gfc_build_library_function_decl (get_identifier
                                        (PREFIX("string_index_char4")),
                                     gfc_charlen_type_node, 5,
                                     gfc_charlen_type_node, pchar4_type_node,
                                     gfc_charlen_type_node, pchar4_type_node,
                                     gfc_logical4_type_node);

  gfor_fndecl_string_scan_char4 =
    gfc_build_library_function_decl (get_identifier
                                        (PREFIX("string_scan_char4")),
                                     gfc_charlen_type_node, 5,
                                     gfc_charlen_type_node, pchar4_type_node,
                                     gfc_charlen_type_node, pchar4_type_node,
                                     gfc_logical4_type_node);

  gfor_fndecl_string_verify_char4 =
    gfc_build_library_function_decl (get_identifier
                                        (PREFIX("string_verify_char4")),
                                     gfc_charlen_type_node, 5,
                                     gfc_charlen_type_node, pchar4_type_node,
                                     gfc_charlen_type_node, pchar4_type_node,
                                     gfc_logical4_type_node);

  gfor_fndecl_string_trim_char4 =
    gfc_build_library_function_decl (get_identifier
                                        (PREFIX("string_trim_char4")),
                                     void_type_node, 4,
                                     build_pointer_type (gfc_charlen_type_node),
                                     build_pointer_type (pchar4_type_node),
                                     gfc_charlen_type_node, pchar4_type_node);

  gfor_fndecl_string_minmax_char4 =
    gfc_build_library_function_decl (get_identifier
                                        (PREFIX("string_minmax_char4")),
                                     void_type_node, -4,
                                     build_pointer_type (gfc_charlen_type_node),
                                     build_pointer_type (pchar4_type_node),
                                     integer_type_node, integer_type_node);

  gfor_fndecl_adjustl_char4 =
    gfc_build_library_function_decl (get_identifier (PREFIX("adjustl_char4")),
                                     void_type_node, 3, pchar4_type_node,
                                     gfc_charlen_type_node, pchar4_type_node);

  gfor_fndecl_adjustr_char4 =
    gfc_build_library_function_decl (get_identifier (PREFIX("adjustr_char4")),
                                     void_type_node, 3, pchar4_type_node,
                                     gfc_charlen_type_node, pchar4_type_node);

  gfor_fndecl_select_string_char4 =
    gfc_build_library_function_decl (get_identifier
                                        (PREFIX("select_string_char4")),
                                     integer_type_node, 4, pvoid_type_node,
                                     integer_type_node, pvoid_type_node,
                                     gfc_charlen_type_node);


  /* Conversion between character kinds.  */

  gfor_fndecl_convert_char1_to_char4 =
    gfc_build_library_function_decl (get_identifier
                                        (PREFIX("convert_char1_to_char4")),
                                     void_type_node, 3,
                                     build_pointer_type (pchar4_type_node),
                                     gfc_charlen_type_node, pchar1_type_node);

  gfor_fndecl_convert_char4_to_char1 =
    gfc_build_library_function_decl (get_identifier
                                        (PREFIX("convert_char4_to_char1")),
                                     void_type_node, 3,
                                     build_pointer_type (pchar1_type_node),
                                     gfc_charlen_type_node, pchar4_type_node);

  /* Misc. functions.  */

  gfor_fndecl_ttynam =
    gfc_build_library_function_decl (get_identifier (PREFIX("ttynam")),
                                     void_type_node,
                                     3,
                                     pchar_type_node,
                                     gfc_charlen_type_node,
                                     integer_type_node);

  gfor_fndecl_fdate =
    gfc_build_library_function_decl (get_identifier (PREFIX("fdate")),
                                     void_type_node,
                                     2,
                                     pchar_type_node,
                                     gfc_charlen_type_node);

  gfor_fndecl_ctime =
    gfc_build_library_function_decl (get_identifier (PREFIX("ctime")),
                                     void_type_node,
                                     3,
                                     pchar_type_node,
                                     gfc_charlen_type_node,
                                     gfc_int8_type_node);

  gfor_fndecl_sc_kind =
    gfc_build_library_function_decl (get_identifier
                                        (PREFIX("selected_char_kind")),
                                     gfc_int4_type_node, 2,
                                     gfc_charlen_type_node, pchar_type_node);

  gfor_fndecl_si_kind =
    gfc_build_library_function_decl (get_identifier
                                        (PREFIX("selected_int_kind")),
                                     gfc_int4_type_node, 1, pvoid_type_node);

  gfor_fndecl_sr_kind =
    gfc_build_library_function_decl (get_identifier
                                        (PREFIX("selected_real_kind")),
                                     gfc_int4_type_node, 2,
                                     pvoid_type_node, pvoid_type_node);

  /* Power functions.  */
  {
    tree ctype, rtype, itype, jtype;
    int rkind, ikind, jkind;
#define NIKINDS 3
#define NRKINDS 4
    static int ikinds[NIKINDS] = {4, 8, 16};
    static int rkinds[NRKINDS] = {4, 8, 10, 16};
    char name[PREFIX_LEN + 12]; /* _gfortran_pow_?n_?n */

    for (ikind=0; ikind < NIKINDS; ikind++)
      {
        itype = gfc_get_int_type (ikinds[ikind]);

        for (jkind=0; jkind < NIKINDS; jkind++)
          {
            jtype = gfc_get_int_type (ikinds[jkind]);
            if (itype && jtype)
              {
                sprintf(name, PREFIX("pow_i%d_i%d"), ikinds[ikind],
                        ikinds[jkind]);
                gfor_fndecl_math_powi[jkind][ikind].integer =
                  gfc_build_library_function_decl (get_identifier (name),
                    jtype, 2, jtype, itype);
                TREE_READONLY (gfor_fndecl_math_powi[jkind][ikind].integer) = 1;
              }
          }

        for (rkind = 0; rkind < NRKINDS; rkind ++)
          {
            rtype = gfc_get_real_type (rkinds[rkind]);
            if (rtype && itype)
              {
                sprintf(name, PREFIX("pow_r%d_i%d"), rkinds[rkind],
                        ikinds[ikind]);
                gfor_fndecl_math_powi[rkind][ikind].real =
                  gfc_build_library_function_decl (get_identifier (name),
                    rtype, 2, rtype, itype);
                TREE_READONLY (gfor_fndecl_math_powi[rkind][ikind].real) = 1;
              }

            ctype = gfc_get_complex_type (rkinds[rkind]);
            if (ctype && itype)
              {
                sprintf(name, PREFIX("pow_c%d_i%d"), rkinds[rkind],
                        ikinds[ikind]);
                gfor_fndecl_math_powi[rkind][ikind].cmplx =
                  gfc_build_library_function_decl (get_identifier (name),
                    ctype, 2,ctype, itype);
                TREE_READONLY (gfor_fndecl_math_powi[rkind][ikind].cmplx) = 1;
              }
          }
      }
#undef NIKINDS
#undef NRKINDS
  }

  gfor_fndecl_math_ishftc4 =
    gfc_build_library_function_decl (get_identifier (PREFIX("ishftc4")),
                                     gfc_int4_type_node,
                                     3, gfc_int4_type_node,
                                     gfc_int4_type_node, gfc_int4_type_node);
  gfor_fndecl_math_ishftc8 =
    gfc_build_library_function_decl (get_identifier (PREFIX("ishftc8")),
                                     gfc_int8_type_node,
                                     3, gfc_int8_type_node,
                                     gfc_int4_type_node, gfc_int4_type_node);
  if (gfc_int16_type_node)
    gfor_fndecl_math_ishftc16 =
      gfc_build_library_function_decl (get_identifier (PREFIX("ishftc16")),
                                       gfc_int16_type_node, 3,
                                       gfc_int16_type_node,
                                       gfc_int4_type_node,
                                       gfc_int4_type_node);

  /* BLAS functions.  */
  {
    tree pint = build_pointer_type (integer_type_node);
    tree ps = build_pointer_type (gfc_get_real_type (gfc_default_real_kind));
    tree pd = build_pointer_type (gfc_get_real_type (gfc_default_double_kind));
    tree pc = build_pointer_type (gfc_get_complex_type (gfc_default_real_kind));
    tree pz = build_pointer_type
                (gfc_get_complex_type (gfc_default_double_kind));

    gfor_fndecl_sgemm = gfc_build_library_function_decl
                          (get_identifier
                             (gfc_option.flag_underscoring ? "sgemm_"
                                                           : "sgemm"),
                           void_type_node, 15, pchar_type_node,
                           pchar_type_node, pint, pint, pint, ps, ps, pint,
                           ps, pint, ps, ps, pint, integer_type_node,
                           integer_type_node);
    gfor_fndecl_dgemm = gfc_build_library_function_decl
                          (get_identifier
                             (gfc_option.flag_underscoring ? "dgemm_"
                                                           : "dgemm"),
                           void_type_node, 15, pchar_type_node,
                           pchar_type_node, pint, pint, pint, pd, pd, pint,
                           pd, pint, pd, pd, pint, integer_type_node,
                           integer_type_node);
    gfor_fndecl_cgemm = gfc_build_library_function_decl
                          (get_identifier
                             (gfc_option.flag_underscoring ? "cgemm_"
                                                           : "cgemm"),
                           void_type_node, 15, pchar_type_node,
                           pchar_type_node, pint, pint, pint, pc, pc, pint,
                           pc, pint, pc, pc, pint, integer_type_node,
                           integer_type_node);
    gfor_fndecl_zgemm = gfc_build_library_function_decl
                          (get_identifier
                             (gfc_option.flag_underscoring ? "zgemm_"
                                                           : "zgemm"),
                           void_type_node, 15, pchar_type_node,
                           pchar_type_node, pint, pint, pint, pz, pz, pint,
                           pz, pint, pz, pz, pint, integer_type_node,
                           integer_type_node);
  }

  /* Other functions.  */
  gfor_fndecl_size0 =
    gfc_build_library_function_decl (get_identifier (PREFIX("size0")),
                                     gfc_array_index_type,
                                     1, pvoid_type_node);
  gfor_fndecl_size1 =
    gfc_build_library_function_decl (get_identifier (PREFIX("size1")),
                                     gfc_array_index_type,
                                     2, pvoid_type_node,
                                     gfc_array_index_type);

  gfor_fndecl_iargc =
    gfc_build_library_function_decl (get_identifier (PREFIX ("iargc")),
                                     gfc_int4_type_node,
                                     0);

  if (gfc_type_for_size (128, true))
    {
      tree uint128 = gfc_type_for_size (128, true);

      gfor_fndecl_clz128 =
        gfc_build_library_function_decl (get_identifier (PREFIX ("clz128")),
                                         integer_type_node, 1, uint128);

      gfor_fndecl_ctz128 =
        gfc_build_library_function_decl (get_identifier (PREFIX ("ctz128")),
                                         integer_type_node, 1, uint128);
    }
}


/* Make prototypes for runtime library functions.  */

void
gfc_build_builtin_function_decls (void)
{
  tree gfc_int4_type_node = gfc_get_int_type (4);

  gfor_fndecl_stop_numeric =
    gfc_build_library_function_decl (get_identifier (PREFIX("stop_numeric")),
                                     void_type_node, 1, gfc_int4_type_node);
  /* STOP doesn't return.  */
  TREE_THIS_VOLATILE (gfor_fndecl_stop_numeric) = 1;


  gfor_fndecl_stop_string =
    gfc_build_library_function_decl (get_identifier (PREFIX("stop_string")),
                                     void_type_node, 2, pchar_type_node,
                                     gfc_int4_type_node);
  /* STOP doesn't return.  */
  TREE_THIS_VOLATILE (gfor_fndecl_stop_string) = 1;


  gfor_fndecl_error_stop_numeric =
    gfc_build_library_function_decl (get_identifier (PREFIX("error_stop_numeric")),
                                     void_type_node, 1, gfc_int4_type_node);
  /* ERROR STOP doesn't return.  */
  TREE_THIS_VOLATILE (gfor_fndecl_error_stop_numeric) = 1;


  gfor_fndecl_error_stop_string =
    gfc_build_library_function_decl (get_identifier (PREFIX("error_stop_string")),
                                     void_type_node, 2, pchar_type_node,
                                     gfc_int4_type_node);
  /* ERROR STOP doesn't return.  */
  TREE_THIS_VOLATILE (gfor_fndecl_error_stop_string) = 1;


  gfor_fndecl_pause_numeric =
    gfc_build_library_function_decl (get_identifier (PREFIX("pause_numeric")),
                                     void_type_node, 1, gfc_int4_type_node);

  gfor_fndecl_pause_string =
    gfc_build_library_function_decl (get_identifier (PREFIX("pause_string")),
                                     void_type_node, 2, pchar_type_node,
                                     gfc_int4_type_node);

  gfor_fndecl_runtime_error =
    gfc_build_library_function_decl (get_identifier (PREFIX("runtime_error")),
                                     void_type_node, -1, pchar_type_node);
  /* The runtime_error function does not return.  */
  TREE_THIS_VOLATILE (gfor_fndecl_runtime_error) = 1;

  gfor_fndecl_runtime_error_at =
    gfc_build_library_function_decl (get_identifier (PREFIX("runtime_error_at")),
                                     void_type_node, -2, pchar_type_node,
                                     pchar_type_node);
  /* The runtime_error_at function does not return.  */
  TREE_THIS_VOLATILE (gfor_fndecl_runtime_error_at) = 1;
  
  gfor_fndecl_runtime_warning_at =
    gfc_build_library_function_decl (get_identifier (PREFIX("runtime_warning_at")),
                                     void_type_node, -2, pchar_type_node,
                                     pchar_type_node);
  gfor_fndecl_generate_error =
    gfc_build_library_function_decl (get_identifier (PREFIX("generate_error")),
                                     void_type_node, 3, pvoid_type_node,
                                     integer_type_node, pchar_type_node);

  gfor_fndecl_os_error =
    gfc_build_library_function_decl (get_identifier (PREFIX("os_error")),
                                     void_type_node, 1, pchar_type_node);
  /* The runtime_error function does not return.  */
  TREE_THIS_VOLATILE (gfor_fndecl_os_error) = 1;

  gfor_fndecl_set_args =
    gfc_build_library_function_decl (get_identifier (PREFIX("set_args")),
                                     void_type_node, 2, integer_type_node,
                                     build_pointer_type (pchar_type_node));

  gfor_fndecl_set_fpe =
    gfc_build_library_function_decl (get_identifier (PREFIX("set_fpe")),
                                    void_type_node, 1, integer_type_node);

  /* Keep the array dimension in sync with the call, later in this file.  */
  gfor_fndecl_set_options =
    gfc_build_library_function_decl (get_identifier (PREFIX("set_options")),
                                    void_type_node, 2, integer_type_node,
                                    build_pointer_type (integer_type_node));

  gfor_fndecl_set_convert =
    gfc_build_library_function_decl (get_identifier (PREFIX("set_convert")),
                                     void_type_node, 1, integer_type_node);

  gfor_fndecl_set_record_marker =
    gfc_build_library_function_decl (get_identifier (PREFIX("set_record_marker")),
                                     void_type_node, 1, integer_type_node);

  gfor_fndecl_set_max_subrecord_length =
    gfc_build_library_function_decl (get_identifier (PREFIX("set_max_subrecord_length")),
                                     void_type_node, 1, integer_type_node);

  gfor_fndecl_in_pack = gfc_build_library_function_decl_with_spec (
        get_identifier (PREFIX("internal_pack")), ".r",
        pvoid_type_node, 1, pvoid_type_node);

  gfor_fndecl_in_unpack = gfc_build_library_function_decl_with_spec (
        get_identifier (PREFIX("internal_unpack")), ".wR",
        void_type_node, 2, pvoid_type_node, pvoid_type_node);

  gfor_fndecl_associated =
    gfc_build_library_function_decl (
                                     get_identifier (PREFIX("associated")),
                                     integer_type_node, 2, ppvoid_type_node,
                                     ppvoid_type_node);

  gfc_build_intrinsic_function_decls ();
  gfc_build_intrinsic_lib_fndecls ();
  gfc_build_io_library_fndecls ();
}


/* Evaluate the length of dummy character variables.  */

static tree
gfc_trans_dummy_character (gfc_symbol *sym, gfc_charlen *cl, tree fnbody)
{
  stmtblock_t body;

  gfc_finish_decl (cl->backend_decl);

  gfc_start_block (&body);

  /* Evaluate the string length expression.  */
  gfc_conv_string_length (cl, NULL, &body);

  gfc_trans_vla_type_sizes (sym, &body);

  gfc_add_expr_to_block (&body, fnbody);
  return gfc_finish_block (&body);
}


/* Allocate and cleanup an automatic character variable.  */

static tree
gfc_trans_auto_character_variable (gfc_symbol * sym, tree fnbody)
{
  stmtblock_t body;
  tree decl;
  tree tmp;

  gcc_assert (sym->backend_decl);
  gcc_assert (sym->ts.u.cl && sym->ts.u.cl->length);

  gfc_start_block (&body);

  /* Evaluate the string length expression.  */
  gfc_conv_string_length (sym->ts.u.cl, NULL, &body);

  gfc_trans_vla_type_sizes (sym, &body);

  decl = sym->backend_decl;

  /* Emit a DECL_EXPR for this variable, which will cause the
     gimplifier to allocate storage, and all that good stuff.  */
  tmp = fold_build1 (DECL_EXPR, TREE_TYPE (decl), decl);
  gfc_add_expr_to_block (&body, tmp);

  gfc_add_expr_to_block (&body, fnbody);
  return gfc_finish_block (&body);
}

/* Set the initial value of ASSIGN statement auxiliary variable explicitly.  */

static tree
gfc_trans_assign_aux_var (gfc_symbol * sym, tree fnbody)
{
  stmtblock_t body;

  gcc_assert (sym->backend_decl);
  gfc_start_block (&body);

  /* Set the initial value to length. See the comments in
     function gfc_add_assign_aux_vars in this file.  */
  gfc_add_modify (&body, GFC_DECL_STRING_LEN (sym->backend_decl),
                       build_int_cst (NULL_TREE, -2));

  gfc_add_expr_to_block (&body, fnbody);
  return gfc_finish_block (&body);
}

static void
gfc_trans_vla_one_sizepos (tree *tp, stmtblock_t *body)
{
  tree t = *tp, var, val;

  if (t == NULL || t == error_mark_node)
    return;
  if (TREE_CONSTANT (t) || DECL_P (t))
    return;

  if (TREE_CODE (t) == SAVE_EXPR)
    {
      if (SAVE_EXPR_RESOLVED_P (t))
        {
          *tp = TREE_OPERAND (t, 0);
          return;
        }
      val = TREE_OPERAND (t, 0);
    }
  else
    val = t;

  var = gfc_create_var_np (TREE_TYPE (t), NULL);
  gfc_add_decl_to_function (var);
  gfc_add_modify (body, var, val);
  if (TREE_CODE (t) == SAVE_EXPR)
    TREE_OPERAND (t, 0) = var;
  *tp = var;
}

static void
gfc_trans_vla_type_sizes_1 (tree type, stmtblock_t *body)
{
  tree t;

  if (type == NULL || type == error_mark_node)
    return;

  type = TYPE_MAIN_VARIANT (type);

  if (TREE_CODE (type) == INTEGER_TYPE)
    {
      gfc_trans_vla_one_sizepos (&TYPE_MIN_VALUE (type), body);
      gfc_trans_vla_one_sizepos (&TYPE_MAX_VALUE (type), body);

      for (t = TYPE_NEXT_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
        {
          TYPE_MIN_VALUE (t) = TYPE_MIN_VALUE (type);
          TYPE_MAX_VALUE (t) = TYPE_MAX_VALUE (type);
        }
    }
  else if (TREE_CODE (type) == ARRAY_TYPE)
    {
      gfc_trans_vla_type_sizes_1 (TREE_TYPE (type), body);
      gfc_trans_vla_type_sizes_1 (TYPE_DOMAIN (type), body);
      gfc_trans_vla_one_sizepos (&TYPE_SIZE (type), body);
      gfc_trans_vla_one_sizepos (&TYPE_SIZE_UNIT (type), body);

      for (t = TYPE_NEXT_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
        {
          TYPE_SIZE (t) = TYPE_SIZE (type);
          TYPE_SIZE_UNIT (t) = TYPE_SIZE_UNIT (type);
        }
    }
}

/* Make sure all type sizes and array domains are either constant,
   or variable or parameter decls.  This is a simplified variant
   of gimplify_type_sizes, but we can't use it here, as none of the
   variables in the expressions have been gimplified yet.
   As type sizes and domains for various variable length arrays
   contain VAR_DECLs that are only initialized at gfc_trans_deferred_vars
   time, without this routine gimplify_type_sizes in the middle-end
   could result in the type sizes being gimplified earlier than where
   those variables are initialized.  */

void
gfc_trans_vla_type_sizes (gfc_symbol *sym, stmtblock_t *body)
{
  tree type = TREE_TYPE (sym->backend_decl);

  if (TREE_CODE (type) == FUNCTION_TYPE
      && (sym->attr.function || sym->attr.result || sym->attr.entry))
    {
      if (! current_fake_result_decl)
        return;

      type = TREE_TYPE (TREE_VALUE (current_fake_result_decl));
    }

  while (POINTER_TYPE_P (type))
    type = TREE_TYPE (type);

  if (GFC_DESCRIPTOR_TYPE_P (type))
    {
      tree etype = GFC_TYPE_ARRAY_DATAPTR_TYPE (type);

      while (POINTER_TYPE_P (etype))
        etype = TREE_TYPE (etype);

      gfc_trans_vla_type_sizes_1 (etype, body);
    }

  gfc_trans_vla_type_sizes_1 (type, body);
}


/* Initialize a derived type by building an lvalue from the symbol
   and using trans_assignment to do the work. Set dealloc to false
   if no deallocation prior the assignment is needed.  */
tree
gfc_init_default_dt (gfc_symbol * sym, tree body, bool dealloc)
{
  stmtblock_t fnblock;
  gfc_expr *e;
  tree tmp;
  tree present;

  gfc_init_block (&fnblock);
  gcc_assert (!sym->attr.allocatable);
  gfc_set_sym_referenced (sym);
  e = gfc_lval_expr_from_sym (sym);
  tmp = gfc_trans_assignment (e, sym->value, false, dealloc);
  if (sym->attr.dummy && (sym->attr.optional
                          || sym->ns->proc_name->attr.entry_master))
    {
      present = gfc_conv_expr_present (sym);
      tmp = build3 (COND_EXPR, TREE_TYPE (tmp), present,
                    tmp, build_empty_stmt (input_location));
    }
  gfc_add_expr_to_block (&fnblock, tmp);
  gfc_free_expr (e);
  if (body)
    gfc_add_expr_to_block (&fnblock, body);
  return gfc_finish_block (&fnblock);
}


/* Initialize INTENT(OUT) derived type dummies.  As well as giving
   them their default initializer, if they do not have allocatable
   components, they have their allocatable components deallocated. */

static tree
init_intent_out_dt (gfc_symbol * proc_sym, tree body)
{
  stmtblock_t fnblock;
  gfc_formal_arglist *f;
  tree tmp;
  tree present;

  gfc_init_block (&fnblock);
  for (f = proc_sym->formal; f; f = f->next)
    if (f->sym && f->sym->attr.intent == INTENT_OUT
        && !f->sym->attr.pointer
        && f->sym->ts.type == BT_DERIVED)
      {
        if (f->sym->ts.u.derived->attr.alloc_comp && !f->sym->value)
          {
            tmp = gfc_deallocate_alloc_comp (f->sym->ts.u.derived,
                                             f->sym->backend_decl,
                                             f->sym->as ? f->sym->as->rank : 0);

            if (f->sym->attr.optional
                || f->sym->ns->proc_name->attr.entry_master)
              {
                present = gfc_conv_expr_present (f->sym);
                tmp = build3 (COND_EXPR, TREE_TYPE (tmp), present,
                              tmp, build_empty_stmt (input_location));
              }

            gfc_add_expr_to_block (&fnblock, tmp);
          }
       else if (f->sym->value)
          body = gfc_init_default_dt (f->sym, body, true);
      }

  gfc_add_expr_to_block (&fnblock, body);
  return gfc_finish_block (&fnblock);
}


/* Generate function entry and exit code, and add it to the function body.
   This includes:
    Allocation and initialization of array variables.
    Allocation of character string variables.
    Initialization and possibly repacking of dummy arrays.
    Initialization of ASSIGN statement auxiliary variable.
    Automatic deallocation.  */

tree
gfc_trans_deferred_vars (gfc_symbol * proc_sym, tree fnbody)
{
  locus loc;
  gfc_symbol *sym;
  gfc_formal_arglist *f;
  stmtblock_t body;
  bool seen_trans_deferred_array = false;

  /* Deal with implicit return variables.  Explicit return variables will
     already have been added.  */
  if (gfc_return_by_reference (proc_sym) && proc_sym->result == proc_sym)
    {
      if (!current_fake_result_decl)
        {
          gfc_entry_list *el = NULL;
          if (proc_sym->attr.entry_master)
            {
              for (el = proc_sym->ns->entries; el; el = el->next)
                if (el->sym != el->sym->result)
                  break;
            }
          /* TODO: move to the appropriate place in resolve.c.  */
          if (warn_return_type && el == NULL)
            gfc_warning ("Return value of function '%s' at %L not set",
                         proc_sym->name, &proc_sym->declared_at);
        }
      else if (proc_sym->as)
        {
          tree result = TREE_VALUE (current_fake_result_decl);
          fnbody = gfc_trans_dummy_array_bias (proc_sym, result, fnbody);

          /* An automatic character length, pointer array result.  */
          if (proc_sym->ts.type == BT_CHARACTER
                && TREE_CODE (proc_sym->ts.u.cl->backend_decl) == VAR_DECL)
            fnbody = gfc_trans_dummy_character (proc_sym, proc_sym->ts.u.cl,
                                                fnbody);
        }
      else if (proc_sym->ts.type == BT_CHARACTER)
        {
          if (TREE_CODE (proc_sym->ts.u.cl->backend_decl) == VAR_DECL)
            fnbody = gfc_trans_dummy_character (proc_sym, proc_sym->ts.u.cl,
                                                fnbody);
        }
      else
        gcc_assert (gfc_option.flag_f2c
                    && proc_sym->ts.type == BT_COMPLEX);
    }

  /* Initialize the INTENT(OUT) derived type dummy arguments.  This
     should be done here so that the offsets and lbounds of arrays
     are available.  */
  fnbody = init_intent_out_dt (proc_sym, fnbody);

  for (sym = proc_sym->tlink; sym != proc_sym; sym = sym->tlink)
    {
      bool sym_has_alloc_comp = (sym->ts.type == BT_DERIVED)
                                   && sym->ts.u.derived->attr.alloc_comp;
      if (sym->attr.dimension)
        {
          switch (sym->as->type)
            {
            case AS_EXPLICIT:
              if (sym->attr.dummy || sym->attr.result)
                fnbody =
                  gfc_trans_dummy_array_bias (sym, sym->backend_decl, fnbody);
              else if (sym->attr.pointer || sym->attr.allocatable)
                {
                  if (TREE_STATIC (sym->backend_decl))
                    gfc_trans_static_array_pointer (sym);
                  else
                    {
                      seen_trans_deferred_array = true;
                      fnbody = gfc_trans_deferred_array (sym, fnbody);
                    }
                }
              else
                {
                  if (sym_has_alloc_comp)
                    {
                      seen_trans_deferred_array = true;
                      fnbody = gfc_trans_deferred_array (sym, fnbody);
                    }
                  else if (sym->ts.type == BT_DERIVED
                             && sym->value
                             && !sym->attr.data
                             && sym->attr.save == SAVE_NONE)
                    fnbody = gfc_init_default_dt (sym, fnbody, false);

                  gfc_get_backend_locus (&loc);
                  gfc_set_backend_locus (&sym->declared_at);
                  fnbody = gfc_trans_auto_array_allocation (sym->backend_decl,
                      sym, fnbody);
                  gfc_set_backend_locus (&loc);
                }
              break;

            case AS_ASSUMED_SIZE:
              /* Must be a dummy parameter.  */
              gcc_assert (sym->attr.dummy || sym->as->cp_was_assumed);

              /* We should always pass assumed size arrays the g77 way.  */
              if (sym->attr.dummy)
                fnbody = gfc_trans_g77_array (sym, fnbody);
              break;

            case AS_ASSUMED_SHAPE:
              /* Must be a dummy parameter.  */
              gcc_assert (sym->attr.dummy);

              fnbody = gfc_trans_dummy_array_bias (sym, sym->backend_decl,
                                                   fnbody);
              break;

            case AS_DEFERRED:
              seen_trans_deferred_array = true;
              fnbody = gfc_trans_deferred_array (sym, fnbody);
              break;

            default:
              gcc_unreachable ();
            }
          if (sym_has_alloc_comp && !seen_trans_deferred_array)
            fnbody = gfc_trans_deferred_array (sym, fnbody);
        }
      else if (sym->attr.allocatable
               || (sym->ts.type == BT_CLASS
                   && CLASS_DATA (sym)->attr.allocatable))
        {
          if (!sym->attr.save)
            {
              /* Nullify and automatic deallocation of allocatable
                 scalars.  */
              tree tmp;
              gfc_expr *e;
              gfc_se se;
              stmtblock_t block;

              e = gfc_lval_expr_from_sym (sym);
              if (sym->ts.type == BT_CLASS)
                gfc_add_component_ref (e, "$data");

              gfc_init_se (&se, NULL);
              se.want_pointer = 1;
              gfc_conv_expr (&se, e);
              gfc_free_expr (e);

              /* Nullify when entering the scope.  */
              gfc_start_block (&block);
              gfc_add_modify (&block, se.expr,
                              fold_convert (TREE_TYPE (se.expr),
                                            null_pointer_node));
              gfc_add_expr_to_block (&block, fnbody);

              /* Deallocate when leaving the scope. Nullifying is not
                 needed.  */
              tmp = gfc_deallocate_with_status (se.expr, NULL_TREE, true,
                                                NULL);
              gfc_add_expr_to_block (&block, tmp);
              fnbody = gfc_finish_block (&block);
            }
        }
      else if (sym_has_alloc_comp)
        fnbody = gfc_trans_deferred_array (sym, fnbody);
      else if (sym->ts.type == BT_CHARACTER)
        {
          gfc_get_backend_locus (&loc);
          gfc_set_backend_locus (&sym->declared_at);
          if (sym->attr.dummy || sym->attr.result)
            fnbody = gfc_trans_dummy_character (sym, sym->ts.u.cl, fnbody);
          else
            fnbody = gfc_trans_auto_character_variable (sym, fnbody);
          gfc_set_backend_locus (&loc);
        }
      else if (sym->attr.assign)
        {
          gfc_get_backend_locus (&loc);
          gfc_set_backend_locus (&sym->declared_at);
          fnbody = gfc_trans_assign_aux_var (sym, fnbody);
          gfc_set_backend_locus (&loc);
        }
      else if (sym->ts.type == BT_DERIVED
                 && sym->value
                 && !sym->attr.data
                 && sym->attr.save == SAVE_NONE)
        fnbody = gfc_init_default_dt (sym, fnbody, false);
      else
        gcc_unreachable ();
    }

  gfc_init_block (&body);

  for (f = proc_sym->formal; f; f = f->next)
    {
      if (f->sym && f->sym->tlink == NULL && f->sym->ts.type == BT_CHARACTER)
        {
          gcc_assert (f->sym->ts.u.cl->backend_decl != NULL);
          if (TREE_CODE (f->sym->ts.u.cl->backend_decl) == PARM_DECL)
            gfc_trans_vla_type_sizes (f->sym, &body);
        }
    }

  if (gfc_return_by_reference (proc_sym) && proc_sym->ts.type == BT_CHARACTER
      && current_fake_result_decl != NULL)
    {
      gcc_assert (proc_sym->ts.u.cl->backend_decl != NULL);
      if (TREE_CODE (proc_sym->ts.u.cl->backend_decl) == PARM_DECL)
        gfc_trans_vla_type_sizes (proc_sym, &body);
    }

  gfc_add_expr_to_block (&body, fnbody);
  return gfc_finish_block (&body);
}

static GTY ((param_is (struct module_htab_entry))) htab_t module_htab;

/* Hash and equality functions for module_htab.  */

static hashval_t
module_htab_do_hash (const void *x)
{
  return htab_hash_string (((const struct module_htab_entry *)x)->name);
}

static int
module_htab_eq (const void *x1, const void *x2)
{
  return strcmp ((((const struct module_htab_entry *)x1)->name),
                 (const char *)x2) == 0;
}

/* Hash and equality functions for module_htab's decls.  */

static hashval_t
module_htab_decls_hash (const void *x)
{
  const_tree t = (const_tree) x;
  const_tree n = DECL_NAME (t);
  if (n == NULL_TREE)
    n = TYPE_NAME (TREE_TYPE (t));
  return htab_hash_string (IDENTIFIER_POINTER (n));
}

static int
module_htab_decls_eq (const void *x1, const void *x2)
{
  const_tree t1 = (const_tree) x1;
  const_tree n1 = DECL_NAME (t1);
  if (n1 == NULL_TREE)
    n1 = TYPE_NAME (TREE_TYPE (t1));
  return strcmp (IDENTIFIER_POINTER (n1), (const char *) x2) == 0;
}

struct module_htab_entry *
gfc_find_module (const char *name)
{
  void **slot;

  if (! module_htab)
    module_htab = htab_create_ggc (10, module_htab_do_hash,
                                   module_htab_eq, NULL);

  slot = htab_find_slot_with_hash (module_htab, name,
                                   htab_hash_string (name), INSERT);
  if (*slot == NULL)
    {
      struct module_htab_entry *entry = ggc_alloc_cleared_module_htab_entry ();

      entry->name = gfc_get_string (name);
      entry->decls = htab_create_ggc (10, module_htab_decls_hash,
                                      module_htab_decls_eq, NULL);
      *slot = (void *) entry;
    }
  return (struct module_htab_entry *) *slot;
}

void
gfc_module_add_decl (struct module_htab_entry *entry, tree decl)
{
  void **slot;
  const char *name;

  if (DECL_NAME (decl))
    name = IDENTIFIER_POINTER (DECL_NAME (decl));
  else
    {
      gcc_assert (TREE_CODE (decl) == TYPE_DECL);
      name = IDENTIFIER_POINTER (TYPE_NAME (TREE_TYPE (decl)));
    }
  slot = htab_find_slot_with_hash (entry->decls, name,
                                   htab_hash_string (name), INSERT);
  if (*slot == NULL)
    *slot = (void *) decl;
}

static struct module_htab_entry *cur_module;

/* Output an initialized decl for a module variable.  */

static void
gfc_create_module_variable (gfc_symbol * sym)
{
  tree decl;

  /* Module functions with alternate entries are dealt with later and
     would get caught by the next condition.  */
  if (sym->attr.entry)
    return;

  /* Make sure we convert the types of the derived types from iso_c_binding
     into (void *).  */
  if (sym->attr.flavor != FL_PROCEDURE && sym->attr.is_iso_c
      && sym->ts.type == BT_DERIVED)
    sym->backend_decl = gfc_typenode_for_spec (&(sym->ts));

  if (sym->attr.flavor == FL_DERIVED
      && sym->backend_decl
      && TREE_CODE (sym->backend_decl) == RECORD_TYPE)
    {
      decl = sym->backend_decl;
      gcc_assert (sym->ns->proc_name->attr.flavor == FL_MODULE);

      /* -fwhole-file mixes up the contexts so these asserts are unnecessary.  */
      if (!(gfc_option.flag_whole_file && sym->attr.use_assoc))
        {
          gcc_assert (TYPE_CONTEXT (decl) == NULL_TREE
                      || TYPE_CONTEXT (decl) == sym->ns->proc_name->backend_decl);
          gcc_assert (DECL_CONTEXT (TYPE_STUB_DECL (decl)) == NULL_TREE
                      || DECL_CONTEXT (TYPE_STUB_DECL (decl))
                           == sym->ns->proc_name->backend_decl);
        }
      TYPE_CONTEXT (decl) = sym->ns->proc_name->backend_decl;
      DECL_CONTEXT (TYPE_STUB_DECL (decl)) = sym->ns->proc_name->backend_decl;
      gfc_module_add_decl (cur_module, TYPE_STUB_DECL (decl));
    }

  /* Only output variables, procedure pointers and array valued,
     or derived type, parameters.  */
  if (sym->attr.flavor != FL_VARIABLE
        && !(sym->attr.flavor == FL_PARAMETER
               && (sym->attr.dimension || sym->ts.type == BT_DERIVED))
        && !(sym->attr.flavor == FL_PROCEDURE && sym->attr.proc_pointer))
    return;

  if ((sym->attr.in_common || sym->attr.in_equivalence) && sym->backend_decl)
    {
      decl = sym->backend_decl;
      gcc_assert (DECL_CONTEXT (decl) == NULL_TREE);
      gcc_assert (sym->ns->proc_name->attr.flavor == FL_MODULE);
      DECL_CONTEXT (decl) = sym->ns->proc_name->backend_decl;
      gfc_module_add_decl (cur_module, decl);
    }

  /* Don't generate variables from other modules. Variables from
     COMMONs will already have been generated.  */
  if (sym->attr.use_assoc || sym->attr.in_common)
    return;

  /* Equivalenced variables arrive here after creation.  */
  if (sym->backend_decl
      && (sym->equiv_built || sym->attr.in_equivalence))
    return;

  if (sym->backend_decl && !sym->attr.vtab)
    internal_error ("backend decl for module variable %s already exists",
                    sym->name);

  /* We always want module variables to be created.  */
  sym->attr.referenced = 1;
  /* Create the decl.  */
  decl = gfc_get_symbol_decl (sym);

  /* Create the variable.  */
  pushdecl (decl);
  gcc_assert (DECL_CONTEXT (decl) == NULL_TREE);
  gcc_assert (sym->ns->proc_name->attr.flavor == FL_MODULE);
  DECL_CONTEXT (decl) = sym->ns->proc_name->backend_decl;
  rest_of_decl_compilation (decl, 1, 0);
  gfc_module_add_decl (cur_module, decl);

  /* Also add length of strings.  */
  if (sym->ts.type == BT_CHARACTER)
    {
      tree length;

      length = sym->ts.u.cl->backend_decl;
      gcc_assert (length || sym->attr.proc_pointer);
      if (length && !INTEGER_CST_P (length))
        {
          pushdecl (length);
          rest_of_decl_compilation (length, 1, 0);
        }
    }
}

/* Emit debug information for USE statements.  */

static void
gfc_trans_use_stmts (gfc_namespace * ns)
{
  gfc_use_list *use_stmt;
  for (use_stmt = ns->use_stmts; use_stmt; use_stmt = use_stmt->next)
    {
      struct module_htab_entry *entry
        = gfc_find_module (use_stmt->module_name);
      gfc_use_rename *rent;

      if (entry->namespace_decl == NULL)
        {
          entry->namespace_decl
            = build_decl (input_location,
                          NAMESPACE_DECL,
                          get_identifier (use_stmt->module_name),
                          void_type_node);
          DECL_EXTERNAL (entry->namespace_decl) = 1;
        }
      gfc_set_backend_locus (&use_stmt->where);
      if (!use_stmt->only_flag)
        (*debug_hooks->imported_module_or_decl) (entry->namespace_decl,
                                                 NULL_TREE,
                                                 ns->proc_name->backend_decl,
                                                 false);
      for (rent = use_stmt->rename; rent; rent = rent->next)
        {
          tree decl, local_name;
          void **slot;

          if (rent->op != INTRINSIC_NONE)
            continue;

          slot = htab_find_slot_with_hash (entry->decls, rent->use_name,
                                           htab_hash_string (rent->use_name),
                                           INSERT);
          if (*slot == NULL)
            {
              gfc_symtree *st;

              st = gfc_find_symtree (ns->sym_root,
                                     rent->local_name[0]
                                     ? rent->local_name : rent->use_name);
              gcc_assert (st);

              /* Sometimes, generic interfaces wind up being over-ruled by a
                 local symbol (see PR41062).  */
              if (!st->n.sym->attr.use_assoc)
                continue;

              if (st->n.sym->backend_decl
                  && DECL_P (st->n.sym->backend_decl)
                  && st->n.sym->module
                  && strcmp (st->n.sym->module, use_stmt->module_name) == 0)
                {
                  gcc_assert (DECL_EXTERNAL (entry->namespace_decl)
                              || (TREE_CODE (st->n.sym->backend_decl)
                                  != VAR_DECL));
                  decl = copy_node (st->n.sym->backend_decl);
                  DECL_CONTEXT (decl) = entry->namespace_decl;
                  DECL_EXTERNAL (decl) = 1;
                  DECL_IGNORED_P (decl) = 0;
                  DECL_INITIAL (decl) = NULL_TREE;
                }
              else
                {
                  *slot = error_mark_node;
                  htab_clear_slot (entry->decls, slot);
                  continue;
                }
              *slot = decl;
            }
          decl = (tree) *slot;
          if (rent->local_name[0])
            local_name = get_identifier (rent->local_name);
          else
            local_name = NULL_TREE;
          gfc_set_backend_locus (&rent->where);
          (*debug_hooks->imported_module_or_decl) (decl, local_name,
                                                   ns->proc_name->backend_decl,
                                                   !use_stmt->only_flag);
        }
    }
}


/* Return true if expr is a constant initializer that gfc_conv_initializer
   will handle.  */

static bool
check_constant_initializer (gfc_expr *expr, gfc_typespec *ts, bool array,
                            bool pointer)
{
  gfc_constructor *c;
  gfc_component *cm;

  if (pointer)
    return true;
  else if (array)
    {
      if (expr->expr_type == EXPR_CONSTANT || expr->expr_type == EXPR_NULL)
        return true;
      else if (expr->expr_type == EXPR_STRUCTURE)
        return check_constant_initializer (expr, ts, false, false);
      else if (expr->expr_type != EXPR_ARRAY)
        return false;
      for (c = gfc_constructor_first (expr->value.constructor);
           c; c = gfc_constructor_next (c))
        {
          if (c->iterator)
            return false;
          if (c->expr->expr_type == EXPR_STRUCTURE)
            {
              if (!check_constant_initializer (c->expr, ts, false, false))
                return false;
            }
          else if (c->expr->expr_type != EXPR_CONSTANT)
            return false;
        }
      return true;
    }
  else switch (ts->type)
    {
    case BT_DERIVED:
      if (expr->expr_type != EXPR_STRUCTURE)
        return false;
      cm = expr->ts.u.derived->components;
      for (c = gfc_constructor_first (expr->value.constructor);
           c; c = gfc_constructor_next (c), cm = cm->next)
        {
          if (!c->expr || cm->attr.allocatable)
            continue;
          if (!check_constant_initializer (c->expr, &cm->ts,
                                           cm->attr.dimension,
                                           cm->attr.pointer))
            return false;
        }
      return true;
    default:
      return expr->expr_type == EXPR_CONSTANT;
    }
}

/* Emit debug info for parameters and unreferenced variables with
   initializers.  */

static void
gfc_emit_parameter_debug_info (gfc_symbol *sym)
{
  tree decl;

  if (sym->attr.flavor != FL_PARAMETER
      && (sym->attr.flavor != FL_VARIABLE || sym->attr.referenced))
    return;

  if (sym->backend_decl != NULL
      || sym->value == NULL
      || sym->attr.use_assoc
      || sym->attr.dummy
      || sym->attr.result
      || sym->attr.function
      || sym->attr.intrinsic
      || sym->attr.pointer
      || sym->attr.allocatable
      || sym->attr.cray_pointee
      || sym->attr.threadprivate
      || sym->attr.is_bind_c
      || sym->attr.subref_array_pointer
      || sym->attr.assign)
    return;

  if (sym->ts.type == BT_CHARACTER)
    {
      gfc_conv_const_charlen (sym->ts.u.cl);
      if (sym->ts.u.cl->backend_decl == NULL
          || TREE_CODE (sym->ts.u.cl->backend_decl) != INTEGER_CST)
        return;
    }
  else if (sym->ts.type == BT_DERIVED && sym->ts.u.derived->attr.alloc_comp)
    return;

  if (sym->as)
    {
      int n;

      if (sym->as->type != AS_EXPLICIT)
        return;
      for (n = 0; n < sym->as->rank; n++)
        if (sym->as->lower[n]->expr_type != EXPR_CONSTANT
            || sym->as->upper[n] == NULL
            || sym->as->upper[n]->expr_type != EXPR_CONSTANT)
          return;
    }

  if (!check_constant_initializer (sym->value, &sym->ts,
                                   sym->attr.dimension, false))
    return;

  /* Create the decl for the variable or constant.  */
  decl = build_decl (input_location,
                     sym->attr.flavor == FL_PARAMETER ? CONST_DECL : VAR_DECL,
                     gfc_sym_identifier (sym), gfc_sym_type (sym));
  if (sym->attr.flavor == FL_PARAMETER)
    TREE_READONLY (decl) = 1;
  gfc_set_decl_location (decl, &sym->declared_at);
  if (sym->attr.dimension)
    GFC_DECL_PACKED_ARRAY (decl) = 1;
  DECL_CONTEXT (decl) = sym->ns->proc_name->backend_decl;
  TREE_STATIC (decl) = 1;
  TREE_USED (decl) = 1;
  if (DECL_CONTEXT (decl) && TREE_CODE (DECL_CONTEXT (decl)) == NAMESPACE_DECL)
    TREE_PUBLIC (decl) = 1;
  DECL_INITIAL (decl)
    = gfc_conv_initializer (sym->value, &sym->ts, TREE_TYPE (decl),
                            sym->attr.dimension, 0);
  debug_hooks->global_decl (decl);
}

/* Generate all the required code for module variables.  */

void
gfc_generate_module_vars (gfc_namespace * ns)
{
  module_namespace = ns;
  cur_module = gfc_find_module (ns->proc_name->name);

  /* Check if the frontend left the namespace in a reasonable state.  */
  gcc_assert (ns->proc_name && !ns->proc_name->tlink);

  /* Generate COMMON blocks.  */
  gfc_trans_common (ns);

  /* Create decls for all the module variables.  */
  gfc_traverse_ns (ns, gfc_create_module_variable);

  cur_module = NULL;

  gfc_trans_use_stmts (ns);
  gfc_traverse_ns (ns, gfc_emit_parameter_debug_info);
}


static void
gfc_generate_contained_functions (gfc_namespace * parent)
{
  gfc_namespace *ns;

  /* We create all the prototypes before generating any code.  */
  for (ns = parent->contained; ns; ns = ns->sibling)
    {
      /* Skip namespaces from used modules.  */
      if (ns->parent != parent)
        continue;

      gfc_create_function_decl (ns);
    }

  for (ns = parent->contained; ns; ns = ns->sibling)
    {
      /* Skip namespaces from used modules.  */
      if (ns->parent != parent)
        continue;

      gfc_generate_function_code (ns);
    }
}


/* Drill down through expressions for the array specification bounds and
   character length calling generate_local_decl for all those variables
   that have not already been declared.  */

static void
generate_local_decl (gfc_symbol *);

/* Traverse expr, marking all EXPR_VARIABLE symbols referenced.  */

static bool
expr_decls (gfc_expr *e, gfc_symbol *sym,
            int *f ATTRIBUTE_UNUSED)
{
  if (e->expr_type != EXPR_VARIABLE
            || sym == e->symtree->n.sym
            || e->symtree->n.sym->mark
            || e->symtree->n.sym->ns != sym->ns)
        return false;

  generate_local_decl (e->symtree->n.sym);
  return false;
}

static void
generate_expr_decls (gfc_symbol *sym, gfc_expr *e)
{
  gfc_traverse_expr (e, sym, expr_decls, 0);
}


/* Check for dependencies in the character length and array spec.  */

static void
generate_dependency_declarations (gfc_symbol *sym)
{
  int i;

  if (sym->ts.type == BT_CHARACTER
      && sym->ts.u.cl
      && sym->ts.u.cl->length
      && sym->ts.u.cl->length->expr_type != EXPR_CONSTANT)
    generate_expr_decls (sym, sym->ts.u.cl->length);

  if (sym->as && sym->as->rank)
    {
      for (i = 0; i < sym->as->rank; i++)
        {
          generate_expr_decls (sym, sym->as->lower[i]);
          generate_expr_decls (sym, sym->as->upper[i]);
        }
    }
}


/* Generate decls for all local variables.  We do this to ensure correct
   handling of expressions which only appear in the specification of
   other functions.  */

static void
generate_local_decl (gfc_symbol * sym)
{
  if (sym->attr.flavor == FL_VARIABLE)
    {
      if (!sym->attr.dummy && !sym->ns->proc_name->attr.entry_master)
        generate_dependency_declarations (sym);

      if (sym->attr.referenced)
        gfc_get_symbol_decl (sym);

      /* Warnings for unused dummy arguments.  */
      else if (sym->attr.dummy)
        {
          /* INTENT(out) dummy arguments are likely meant to be set.  */
          if (gfc_option.warn_unused_dummy_argument
              && sym->attr.intent == INTENT_OUT)
            {
              if (sym->ts.type != BT_DERIVED)
                gfc_warning ("Dummy argument '%s' at %L was declared "
                             "INTENT(OUT) but was not set",  sym->name,
                             &sym->declared_at);
              else if (!gfc_has_default_initializer (sym->ts.u.derived))
                gfc_warning ("Derived-type dummy argument '%s' at %L was "
                             "declared INTENT(OUT) but was not set and "
                             "does not have a default initializer",
                             sym->name, &sym->declared_at);
            }
          else if (gfc_option.warn_unused_dummy_argument)
            gfc_warning ("Unused dummy argument '%s' at %L", sym->name,
                         &sym->declared_at);
        }

      /* Warn for unused variables, but not if they're inside a common
         block or are use-associated.  */
      else if (warn_unused_variable
               && !(sym->attr.in_common || sym->attr.use_assoc || sym->mark))
        gfc_warning ("Unused variable '%s' declared at %L", sym->name,
                     &sym->declared_at);

      /* For variable length CHARACTER parameters, the PARM_DECL already
         references the length variable, so force gfc_get_symbol_decl
         even when not referenced.  If optimize > 0, it will be optimized
         away anyway.  But do this only after emitting -Wunused-parameter
         warning if requested.  */
      if (sym->attr.dummy && !sym->attr.referenced
            && sym->ts.type == BT_CHARACTER
            && sym->ts.u.cl->backend_decl != NULL
            && TREE_CODE (sym->ts.u.cl->backend_decl) == VAR_DECL)
        {
          sym->attr.referenced = 1;
          gfc_get_symbol_decl (sym);
        }

      /* INTENT(out) dummy arguments and result variables with allocatable
         components are reset by default and need to be set referenced to
         generate the code for nullification and automatic lengths.  */
      if (!sym->attr.referenced
            && sym->ts.type == BT_DERIVED
            && sym->ts.u.derived->attr.alloc_comp
            && !sym->attr.pointer
            && ((sym->attr.dummy && sym->attr.intent == INTENT_OUT)
                  ||
                (sym->attr.result && sym != sym->result)))
        {
          sym->attr.referenced = 1;
          gfc_get_symbol_decl (sym);
        }

      /* Check for dependencies in the array specification and string
        length, adding the necessary declarations to the function.  We
        mark the symbol now, as well as in traverse_ns, to prevent
        getting stuck in a circular dependency.  */
      sym->mark = 1;

      /* We do not want the middle-end to warn about unused parameters
         as this was already done above.  */
      if (sym->attr.dummy && sym->backend_decl != NULL_TREE)
          TREE_NO_WARNING(sym->backend_decl) = 1;
    }
  else if (sym->attr.flavor == FL_PARAMETER)
    {
      if (warn_unused_parameter
           && !sym->attr.referenced
           && !sym->attr.use_assoc)
        gfc_warning ("Unused parameter '%s' declared at %L", sym->name,
                     &sym->declared_at);
    }
  else if (sym->attr.flavor == FL_PROCEDURE)
    {
      /* TODO: move to the appropriate place in resolve.c.  */
      if (warn_return_type
          && sym->attr.function
          && sym->result
          && sym != sym->result
          && !sym->result->attr.referenced
          && !sym->attr.use_assoc
          && sym->attr.if_source != IFSRC_IFBODY)
        {
          gfc_warning ("Return value '%s' of function '%s' declared at "
                       "%L not set", sym->result->name, sym->name,
                        &sym->result->declared_at);

          /* Prevents "Unused variable" warning for RESULT variables.  */
          sym->result->mark = 1;
        }
    }

  if (sym->attr.dummy == 1)
    {
      /* Modify the tree type for scalar character dummy arguments of bind(c)
         procedures if they are passed by value.  The tree type for them will
         be promoted to INTEGER_TYPE for the middle end, which appears to be
         what C would do with characters passed by-value.  The value attribute
         implies the dummy is a scalar.  */
      if (sym->attr.value == 1 && sym->backend_decl != NULL
          && sym->ts.type == BT_CHARACTER && sym->ts.is_c_interop
          && sym->ns->proc_name != NULL && sym->ns->proc_name->attr.is_bind_c)
        gfc_conv_scalar_char_value (sym, NULL, NULL);
    }

  /* Make sure we convert the types of the derived types from iso_c_binding
     into (void *).  */
  if (sym->attr.flavor != FL_PROCEDURE && sym->attr.is_iso_c
      && sym->ts.type == BT_DERIVED)
    sym->backend_decl = gfc_typenode_for_spec (&(sym->ts));
}

static void
generate_local_vars (gfc_namespace * ns)
{
  gfc_traverse_ns (ns, generate_local_decl);
}


/* Generate a switch statement to jump to the correct entry point.  Also
   creates the label decls for the entry points.  */

static tree
gfc_trans_entry_master_switch (gfc_entry_list * el)
{
  stmtblock_t block;
  tree label;
  tree tmp;
  tree val;

  gfc_init_block (&block);
  for (; el; el = el->next)
    {
      /* Add the case label.  */
      label = gfc_build_label_decl (NULL_TREE);
      val = build_int_cst (gfc_array_index_type, el->id);
      tmp = build3_v (CASE_LABEL_EXPR, val, NULL_TREE, label);
      gfc_add_expr_to_block (&block, tmp);

      /* And jump to the actual entry point.  */
      label = gfc_build_label_decl (NULL_TREE);
      tmp = build1_v (GOTO_EXPR, label);
      gfc_add_expr_to_block (&block, tmp);

      /* Save the label decl.  */
      el->label = label;
    }
  tmp = gfc_finish_block (&block);
  /* The first argument selects the entry point.  */
  val = DECL_ARGUMENTS (current_function_decl);
  tmp = build3_v (SWITCH_EXPR, val, tmp, NULL_TREE);
  return tmp;
}


/* Add code to string lengths of actual arguments passed to a function against
   the expected lengths of the dummy arguments.  */

static void
add_argument_checking (stmtblock_t *block, gfc_symbol *sym)
{
  gfc_formal_arglist *formal;

  for (formal = sym->formal; formal; formal = formal->next)
    if (formal->sym && formal->sym->ts.type == BT_CHARACTER)
      {
        enum tree_code comparison;
        tree cond;
        tree argname;
        gfc_symbol *fsym;
        gfc_charlen *cl;
        const char *message;

        fsym = formal->sym;
        cl = fsym->ts.u.cl;

        gcc_assert (cl);
        gcc_assert (cl->passed_length != NULL_TREE);
        gcc_assert (cl->backend_decl != NULL_TREE);

        /* For POINTER, ALLOCATABLE and assumed-shape dummy arguments, the
           string lengths must match exactly.  Otherwise, it is only required
           that the actual string length is *at least* the expected one.
           Sequence association allows for a mismatch of the string length
           if the actual argument is (part of) an array, but only if the
           dummy argument is an array. (See "Sequence association" in
           Section 12.4.1.4 for F95 and 12.4.1.5 for F2003.)  */
        if (fsym->attr.pointer || fsym->attr.allocatable
            || (fsym->as && fsym->as->type == AS_ASSUMED_SHAPE))
          {
            comparison = NE_EXPR;
            message = _("Actual string length does not match the declared one"
                        " for dummy argument '%s' (%ld/%ld)");
          }
        else if (fsym->as && fsym->as->rank != 0)
          continue;
        else
          {
            comparison = LT_EXPR;
            message = _("Actual string length is shorter than the declared one"
                        " for dummy argument '%s' (%ld/%ld)");
          }

        /* Build the condition.  For optional arguments, an actual length
           of 0 is also acceptable if the associated string is NULL, which
           means the argument was not passed.  */
        cond = fold_build2 (comparison, boolean_type_node,
                            cl->passed_length, cl->backend_decl);
        if (fsym->attr.optional)
          {
            tree not_absent;
            tree not_0length;
            tree absent_failed;

            not_0length = fold_build2 (NE_EXPR, boolean_type_node,
                                       cl->passed_length,
                                       fold_convert (gfc_charlen_type_node,
                                                     integer_zero_node));
            /* The symbol needs to be referenced for gfc_get_symbol_decl.  */
            fsym->attr.referenced = 1;
            not_absent = gfc_conv_expr_present (fsym);

            absent_failed = fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
                                         not_0length, not_absent);

            cond = fold_build2 (TRUTH_AND_EXPR, boolean_type_node,
                                cond, absent_failed);
          }

        /* Build the runtime check.  */
        argname = gfc_build_cstring_const (fsym->name);
        argname = gfc_build_addr_expr (pchar_type_node, argname);
        gfc_trans_runtime_check (true, false, cond, block, &fsym->declared_at,
                                 message, argname,
                                 fold_convert (long_integer_type_node,
                                               cl->passed_length),
                                 fold_convert (long_integer_type_node,
                                               cl->backend_decl));
      }
}


static void
create_main_function (tree fndecl)
{
  tree old_context;
  tree ftn_main;
  tree tmp, decl, result_decl, argc, argv, typelist, arglist;
  stmtblock_t body;

  old_context = current_function_decl;

  if (old_context)
    {
      push_function_context ();
      saved_parent_function_decls = saved_function_decls;
      saved_function_decls = NULL_TREE;
    }

  /* main() function must be declared with global scope.  */
  gcc_assert (current_function_decl == NULL_TREE);

  /* Declare the function.  */
  tmp =  build_function_type_list (integer_type_node, integer_type_node,
                                   build_pointer_type (pchar_type_node),
                                   NULL_TREE);
  main_identifier_node = get_identifier ("main");
  ftn_main = build_decl (input_location, FUNCTION_DECL,
                         main_identifier_node, tmp);
  DECL_EXTERNAL (ftn_main) = 0;
  TREE_PUBLIC (ftn_main) = 1;
  TREE_STATIC (ftn_main) = 1;
  DECL_ATTRIBUTES (ftn_main)
      = tree_cons (get_identifier("externally_visible"), NULL_TREE, NULL_TREE);

  /* Setup the result declaration (for "return 0").  */
  result_decl = build_decl (input_location,
                            RESULT_DECL, NULL_TREE, integer_type_node);
  DECL_ARTIFICIAL (result_decl) = 1;
  DECL_IGNORED_P (result_decl) = 1;
  DECL_CONTEXT (result_decl) = ftn_main;
  DECL_RESULT (ftn_main) = result_decl;

  pushdecl (ftn_main);

  /* Get the arguments.  */

  arglist = NULL_TREE;
  typelist = TYPE_ARG_TYPES (TREE_TYPE (ftn_main));

  tmp = TREE_VALUE (typelist);
  argc = build_decl (input_location, PARM_DECL, get_identifier ("argc"), tmp);
  DECL_CONTEXT (argc) = ftn_main;
  DECL_ARG_TYPE (argc) = TREE_VALUE (typelist);
  TREE_READONLY (argc) = 1;
  gfc_finish_decl (argc);
  arglist = chainon (arglist, argc);

  typelist = TREE_CHAIN (typelist);
  tmp = TREE_VALUE (typelist);
  argv = build_decl (input_location, PARM_DECL, get_identifier ("argv"), tmp);
  DECL_CONTEXT (argv) = ftn_main;
  DECL_ARG_TYPE (argv) = TREE_VALUE (typelist);
  TREE_READONLY (argv) = 1;
  DECL_BY_REFERENCE (argv) = 1;
  gfc_finish_decl (argv);
  arglist = chainon (arglist, argv);

  DECL_ARGUMENTS (ftn_main) = arglist;
  current_function_decl = ftn_main;
  announce_function (ftn_main);

  rest_of_decl_compilation (ftn_main, 1, 0);
  make_decl_rtl (ftn_main);
  init_function_start (ftn_main);
  pushlevel (0);

  gfc_init_block (&body);

  /* Call some libgfortran initialization routines, call then MAIN__(). */

  /* Call _gfortran_set_args (argc, argv).  */
  TREE_USED (argc) = 1;
  TREE_USED (argv) = 1;
  tmp = build_call_expr_loc (input_location,
                         gfor_fndecl_set_args, 2, argc, argv);
  gfc_add_expr_to_block (&body, tmp);

  /* Add a call to set_options to set up the runtime library Fortran
     language standard parameters.  */
  {
    tree array_type, array, var;
    VEC(constructor_elt,gc) *v = NULL;

    /* Passing a new option to the library requires four modifications:
     + add it to the tree_cons list below
          + change the array size in the call to build_array_type
          + change the first argument to the library call
            gfor_fndecl_set_options
          + modify the library (runtime/compile_options.c)!  */

    CONSTRUCTOR_APPEND_ELT (v, NULL_TREE,
                            build_int_cst (integer_type_node,
                                           gfc_option.warn_std));
    CONSTRUCTOR_APPEND_ELT (v, NULL_TREE,
                            build_int_cst (integer_type_node,
                                           gfc_option.allow_std));
    CONSTRUCTOR_APPEND_ELT (v, NULL_TREE,
                            build_int_cst (integer_type_node, pedantic));
    CONSTRUCTOR_APPEND_ELT (v, NULL_TREE,
                            build_int_cst (integer_type_node,
                                           gfc_option.flag_dump_core));
    CONSTRUCTOR_APPEND_ELT (v, NULL_TREE,
                            build_int_cst (integer_type_node,
                                           gfc_option.flag_backtrace));
    CONSTRUCTOR_APPEND_ELT (v, NULL_TREE,
                            build_int_cst (integer_type_node,
                                           gfc_option.flag_sign_zero));
    CONSTRUCTOR_APPEND_ELT (v, NULL_TREE,
                            build_int_cst (integer_type_node,
                                           (gfc_option.rtcheck
                                            & GFC_RTCHECK_BOUNDS)));
    CONSTRUCTOR_APPEND_ELT (v, NULL_TREE,
                            build_int_cst (integer_type_node,
                                           gfc_option.flag_range_check));

    array_type = build_array_type (integer_type_node,
                       build_index_type (build_int_cst (NULL_TREE, 7)));
    array = build_constructor (array_type, v);
    TREE_CONSTANT (array) = 1;
    TREE_STATIC (array) = 1;

    /* Create a static variable to hold the jump table.  */
    var = gfc_create_var (array_type, "options");
    TREE_CONSTANT (var) = 1;
    TREE_STATIC (var) = 1;
    TREE_READONLY (var) = 1;
    DECL_INITIAL (var) = array;
    var = gfc_build_addr_expr (build_pointer_type (integer_type_node), var);

    tmp = build_call_expr_loc (input_location,
                           gfor_fndecl_set_options, 2,
                           build_int_cst (integer_type_node, 8), var);
    gfc_add_expr_to_block (&body, tmp);
  }

  /* If -ffpe-trap option was provided, add a call to set_fpe so that
     the library will raise a FPE when needed.  */
  if (gfc_option.fpe != 0)
    {
      tmp = build_call_expr_loc (input_location,
                             gfor_fndecl_set_fpe, 1,
                             build_int_cst (integer_type_node,
                                            gfc_option.fpe));
      gfc_add_expr_to_block (&body, tmp);
    }

  /* If this is the main program and an -fconvert option was provided,
     add a call to set_convert.  */

  if (gfc_option.convert != GFC_CONVERT_NATIVE)
    {
      tmp = build_call_expr_loc (input_location,
                             gfor_fndecl_set_convert, 1,
                             build_int_cst (integer_type_node,
                                            gfc_option.convert));
      gfc_add_expr_to_block (&body, tmp);
    }

  /* If this is the main program and an -frecord-marker option was provided,
     add a call to set_record_marker.  */

  if (gfc_option.record_marker != 0)
    {
      tmp = build_call_expr_loc (input_location,
                             gfor_fndecl_set_record_marker, 1,
                             build_int_cst (integer_type_node,
                                            gfc_option.record_marker));
      gfc_add_expr_to_block (&body, tmp);
    }

  if (gfc_option.max_subrecord_length != 0)
    {
      tmp = build_call_expr_loc (input_location,
                             gfor_fndecl_set_max_subrecord_length, 1,
                             build_int_cst (integer_type_node,
                                            gfc_option.max_subrecord_length));
      gfc_add_expr_to_block (&body, tmp);
    }

  /* Call MAIN__().  */
  tmp = build_call_expr_loc (input_location,
                         fndecl, 0);
  gfc_add_expr_to_block (&body, tmp);

  /* Mark MAIN__ as used.  */
  TREE_USED (fndecl) = 1;

  /* "return 0".  */
  tmp = fold_build2 (MODIFY_EXPR, integer_type_node, DECL_RESULT (ftn_main),
                     build_int_cst (integer_type_node, 0));
  tmp = build1_v (RETURN_EXPR, tmp);
  gfc_add_expr_to_block (&body, tmp);


  DECL_SAVED_TREE (ftn_main) = gfc_finish_block (&body);
  decl = getdecls ();

  /* Finish off this function and send it for code generation.  */
  poplevel (1, 0, 1);
  BLOCK_SUPERCONTEXT (DECL_INITIAL (ftn_main)) = ftn_main;

  DECL_SAVED_TREE (ftn_main)
    = build3_v (BIND_EXPR, decl, DECL_SAVED_TREE (ftn_main),
                DECL_INITIAL (ftn_main));

  /* Output the GENERIC tree.  */
  dump_function (TDI_original, ftn_main);

  cgraph_finalize_function (ftn_main, true);

  if (old_context)
    {
      pop_function_context ();
      saved_function_decls = saved_parent_function_decls;
    }
  current_function_decl = old_context;
}


/* Generate code for a function.  */

void
gfc_generate_function_code (gfc_namespace * ns)
{
  tree fndecl;
  tree old_context;
  tree decl;
  tree tmp;
  tree tmp2;
  stmtblock_t block;
  stmtblock_t body;
  tree result;
  tree recurcheckvar = NULL_TREE;
  gfc_symbol *sym;
  int rank;
  bool is_recursive;

  sym = ns->proc_name;

  /* Check that the frontend isn't still using this.  */
  gcc_assert (sym->tlink == NULL);
  sym->tlink = sym;

  /* Create the declaration for functions with global scope.  */
  if (!sym->backend_decl)
    gfc_create_function_decl (ns);

  fndecl = sym->backend_decl;
  old_context = current_function_decl;

  if (old_context)
    {
      push_function_context ();
      saved_parent_function_decls = saved_function_decls;
      saved_function_decls = NULL_TREE;
    }

  trans_function_start (sym);

  gfc_init_block (&block);

  if (ns->entries && ns->proc_name->ts.type == BT_CHARACTER)
    {
      /* Copy length backend_decls to all entry point result
         symbols.  */
      gfc_entry_list *el;
      tree backend_decl;

      gfc_conv_const_charlen (ns->proc_name->ts.u.cl);
      backend_decl = ns->proc_name->result->ts.u.cl->backend_decl;
      for (el = ns->entries; el; el = el->next)
        el->sym->result->ts.u.cl->backend_decl = backend_decl;
    }

  /* Translate COMMON blocks.  */
  gfc_trans_common (ns);

  /* Null the parent fake result declaration if this namespace is
     a module function or an external procedures.  */
  if ((ns->parent && ns->parent->proc_name->attr.flavor == FL_MODULE)
        || ns->parent == NULL)
    parent_fake_result_decl = NULL_TREE;

  gfc_generate_contained_functions (ns);

  nonlocal_dummy_decls = NULL;
  nonlocal_dummy_decl_pset = NULL;

  generate_local_vars (ns);

  /* Keep the parent fake result declaration in module functions
     or external procedures.  */
  if ((ns->parent && ns->parent->proc_name->attr.flavor == FL_MODULE)
        || ns->parent == NULL)
    current_fake_result_decl = parent_fake_result_decl;
  else
    current_fake_result_decl = NULL_TREE;

  current_function_return_label = NULL;

  /* Now generate the code for the body of this function.  */
  gfc_init_block (&body);

   is_recursive = sym->attr.recursive
                  || (sym->attr.entry_master
                      && sym->ns->entries->sym->attr.recursive);
   if ((gfc_option.rtcheck & GFC_RTCHECK_RECURSION)
          && !is_recursive
          && !gfc_option.flag_recursive)
     {
       char * msg;

       asprintf (&msg, "Recursive call to nonrecursive procedure '%s'",
                 sym->name);
       recurcheckvar = gfc_create_var (boolean_type_node, "is_recursive");
       TREE_STATIC (recurcheckvar) = 1;
       DECL_INITIAL (recurcheckvar) = boolean_false_node;
       gfc_add_expr_to_block (&block, recurcheckvar);
       gfc_trans_runtime_check (true, false, recurcheckvar, &block,
                                &sym->declared_at, msg);
       gfc_add_modify (&block, recurcheckvar, boolean_true_node);
       gfc_free (msg);
    }

  if (TREE_TYPE (DECL_RESULT (fndecl)) != void_type_node
        && sym->attr.subroutine)
    {
      tree alternate_return;
      alternate_return = gfc_get_fake_result_decl (sym, 0);
      gfc_add_modify (&body, alternate_return, integer_zero_node);
    }

  if (ns->entries)
    {
      /* Jump to the correct entry point.  */
      tmp = gfc_trans_entry_master_switch (ns->entries);
      gfc_add_expr_to_block (&body, tmp);
    }

  /* If bounds-checking is enabled, generate code to check passed in actual
     arguments against the expected dummy argument attributes (e.g. string
     lengths).  */
  if ((gfc_option.rtcheck & GFC_RTCHECK_BOUNDS) && !sym->attr.is_bind_c)
    add_argument_checking (&body, sym);

  tmp = gfc_trans_code (ns->code);
  gfc_add_expr_to_block (&body, tmp);

  /* Add a return label if needed.  */
  if (current_function_return_label)
    {
      tmp = build1_v (LABEL_EXPR, current_function_return_label);
      gfc_add_expr_to_block (&body, tmp);
    }

  tmp = gfc_finish_block (&body);
  /* Add code to create and cleanup arrays.  */
  tmp = gfc_trans_deferred_vars (sym, tmp);

  if (TREE_TYPE (DECL_RESULT (fndecl)) != void_type_node)
    {
      if (sym->attr.subroutine || sym == sym->result)
        {
          if (current_fake_result_decl != NULL)
            result = TREE_VALUE (current_fake_result_decl);
          else
            result = NULL_TREE;
          current_fake_result_decl = NULL_TREE;
        }
      else
        result = sym->result->backend_decl;

      if (result != NULL_TREE
            && sym->attr.function
            && !sym->attr.pointer)
        {
          if (sym->ts.type == BT_DERIVED
              && sym->ts.u.derived->attr.alloc_comp)
            {
              rank = sym->as ? sym->as->rank : 0;
              tmp2 = gfc_nullify_alloc_comp (sym->ts.u.derived, result, rank);
              gfc_add_expr_to_block (&block, tmp2);
            }
          else if (sym->attr.allocatable && sym->attr.dimension == 0)
            gfc_add_modify (&block, result, fold_convert (TREE_TYPE (result),
                                                          null_pointer_node));
        }

      gfc_add_expr_to_block (&block, tmp);

      /* Reset recursion-check variable.  */
      if ((gfc_option.rtcheck & GFC_RTCHECK_RECURSION)
             && !is_recursive
             && !gfc_option.flag_openmp
             && recurcheckvar != NULL_TREE)
        {
          gfc_add_modify (&block, recurcheckvar, boolean_false_node);
          recurcheckvar = NULL;
        }

      if (result == NULL_TREE)
        {
          /* TODO: move to the appropriate place in resolve.c.  */
          if (warn_return_type && !sym->attr.referenced && sym == sym->result)
            gfc_warning ("Return value of function '%s' at %L not set",
                         sym->name, &sym->declared_at);

          TREE_NO_WARNING(sym->backend_decl) = 1;
        }
      else
        {
          /* Set the return value to the dummy result variable.  The
             types may be different for scalar default REAL functions
             with -ff2c, therefore we have to convert.  */
          tmp = convert (TREE_TYPE (DECL_RESULT (fndecl)), result);
          tmp = fold_build2 (MODIFY_EXPR, TREE_TYPE (tmp),
                             DECL_RESULT (fndecl), tmp);
          tmp = build1_v (RETURN_EXPR, tmp);
          gfc_add_expr_to_block (&block, tmp);
        }
    }
  else
    {
      gfc_add_expr_to_block (&block, tmp);
      /* Reset recursion-check variable.  */
      if ((gfc_option.rtcheck & GFC_RTCHECK_RECURSION)
             && !is_recursive
             && !gfc_option.flag_openmp
             && recurcheckvar != NULL_TREE)
        {
          gfc_add_modify (&block, recurcheckvar, boolean_false_node);
          recurcheckvar = NULL_TREE;
        }
    }


  /* Add all the decls we created during processing.  */
  decl = saved_function_decls;
  while (decl)
    {
      tree next;

      next = TREE_CHAIN (decl);
      TREE_CHAIN (decl) = NULL_TREE;
      pushdecl (decl);
      decl = next;
    }
  saved_function_decls = NULL_TREE;

  DECL_SAVED_TREE (fndecl) = gfc_finish_block (&block);
  decl = getdecls ();

  /* Finish off this function and send it for code generation.  */
  poplevel (1, 0, 1);
  BLOCK_SUPERCONTEXT (DECL_INITIAL (fndecl)) = fndecl;

  DECL_SAVED_TREE (fndecl)
    = build3_v (BIND_EXPR, decl, DECL_SAVED_TREE (fndecl),
                DECL_INITIAL (fndecl));

  if (nonlocal_dummy_decls)
    {
      BLOCK_VARS (DECL_INITIAL (fndecl))
        = chainon (BLOCK_VARS (DECL_INITIAL (fndecl)), nonlocal_dummy_decls);
      pointer_set_destroy (nonlocal_dummy_decl_pset);
      nonlocal_dummy_decls = NULL;
      nonlocal_dummy_decl_pset = NULL;
    }

  /* Output the GENERIC tree.  */
  dump_function (TDI_original, fndecl);

  /* Store the end of the function, so that we get good line number
     info for the epilogue.  */
  cfun->function_end_locus = input_location;

  /* We're leaving the context of this function, so zap cfun.
     It's still in DECL_STRUCT_FUNCTION, and we'll restore it in
     tree_rest_of_compilation.  */
  set_cfun (NULL);

  if (old_context)
    {
      pop_function_context ();
      saved_function_decls = saved_parent_function_decls;
    }
  current_function_decl = old_context;

  if (decl_function_context (fndecl))
    /* Register this function with cgraph just far enough to get it
       added to our parent's nested function list.  */
    (void) cgraph_node (fndecl);
  else
    cgraph_finalize_function (fndecl, true);

  gfc_trans_use_stmts (ns);
  gfc_traverse_ns (ns, gfc_emit_parameter_debug_info);

  if (sym->attr.is_main_program)
    create_main_function (fndecl);
}


void
gfc_generate_constructors (void)
{
  gcc_assert (gfc_static_ctors == NULL_TREE);
#if 0
  tree fnname;
  tree type;
  tree fndecl;
  tree decl;
  tree tmp;

  if (gfc_static_ctors == NULL_TREE)
    return;

  fnname = get_file_function_name ("I");
  type = build_function_type_list (void_type_node, NULL_TREE);

  fndecl = build_decl (input_location,
                       FUNCTION_DECL, fnname, type);
  TREE_PUBLIC (fndecl) = 1;

  decl = build_decl (input_location,
                     RESULT_DECL, NULL_TREE, void_type_node);
  DECL_ARTIFICIAL (decl) = 1;
  DECL_IGNORED_P (decl) = 1;
  DECL_CONTEXT (decl) = fndecl;
  DECL_RESULT (fndecl) = decl;

  pushdecl (fndecl);

  current_function_decl = fndecl;

  rest_of_decl_compilation (fndecl, 1, 0);

  make_decl_rtl (fndecl);

  init_function_start (fndecl);

  pushlevel (0);

  for (; gfc_static_ctors; gfc_static_ctors = TREE_CHAIN (gfc_static_ctors))
    {
      tmp = build_call_expr_loc (input_location,
                             TREE_VALUE (gfc_static_ctors), 0);
      DECL_SAVED_TREE (fndecl) = build_stmt (input_location, EXPR_STMT, tmp);
    }

  decl = getdecls ();
  poplevel (1, 0, 1);

  BLOCK_SUPERCONTEXT (DECL_INITIAL (fndecl)) = fndecl;
  DECL_SAVED_TREE (fndecl)
    = build3_v (BIND_EXPR, decl, DECL_SAVED_TREE (fndecl),
                DECL_INITIAL (fndecl));

  free_after_parsing (cfun);
  free_after_compilation (cfun);

  tree_rest_of_compilation (fndecl);

  current_function_decl = NULL_TREE;
#endif
}

/* Translates a BLOCK DATA program unit. This means emitting the
   commons contained therein plus their initializations. We also emit
   a globally visible symbol to make sure that each BLOCK DATA program
   unit remains unique.  */

void
gfc_generate_block_data (gfc_namespace * ns)
{
  tree decl;
  tree id;

  /* Tell the backend the source location of the block data.  */
  if (ns->proc_name)
    gfc_set_backend_locus (&ns->proc_name->declared_at);
  else
    gfc_set_backend_locus (&gfc_current_locus);

  /* Process the DATA statements.  */
  gfc_trans_common (ns);

  /* Create a global symbol with the mane of the block data.  This is to
     generate linker errors if the same name is used twice.  It is never
     really used.  */
  if (ns->proc_name)
    id = gfc_sym_mangled_function_id (ns->proc_name);
  else
    id = get_identifier ("__BLOCK_DATA__");

  decl = build_decl (input_location,
                     VAR_DECL, id, gfc_array_index_type);
  TREE_PUBLIC (decl) = 1;
  TREE_STATIC (decl) = 1;
  DECL_IGNORED_P (decl) = 1;

  pushdecl (decl);
  rest_of_decl_compilation (decl, 1, 0);
}


/* Process the local variables of a BLOCK construct.  */

void
gfc_process_block_locals (gfc_namespace* ns)
{
  tree decl;

  gcc_assert (saved_local_decls == NULL_TREE);
  generate_local_vars (ns);

  decl = saved_local_decls;
  while (decl)
    {
      tree next;

      next = TREE_CHAIN (decl);
      TREE_CHAIN (decl) = NULL_TREE;
      pushdecl (decl);
      decl = next;
    }
  saved_local_decls = NULL_TREE;
}


#include "gt-fortran-trans-decl.h"