[gcc.git] / gcc / ada / decl.c

/****************************************************************************
 *                                                                          *
 *                         GNAT COMPILER COMPONENTS                         *
 *                                                                          *
 *                                 D E C L                                  *
 *                                                                          *
 *                          C Implementation File                           *
 *                                                                          *
 *          Copyright (C) 1992-2007, Free Software Foundation, Inc.         *
 *                                                                          *
 * GNAT is free software;  you can  redistribute it  and/or modify it under *
 * terms of the  GNU General Public License as published  by the Free Soft- *
 * ware  Foundation;  either version 2,  or (at your option) any later ver- *
 * sion.  GNAT is distributed in the hope that it will be useful, but WITH- *
 * OUT 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  distributed with GNAT;  see file COPYING.  If not, write *
 * to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, *
 * Boston, MA 02110-1301, USA.                                              *
 *                                                                          *
 * GNAT was originally developed  by the GNAT team at  New York University. *
 * Extensive contributions were provided by Ada Core Technologies Inc.      *
 *                                                                          *
 ****************************************************************************/

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "flags.h"
#include "toplev.h"
#include "convert.h"
#include "ggc.h"
#include "obstack.h"
#include "target.h"
#include "expr.h"

#include "ada.h"
#include "types.h"
#include "atree.h"
#include "elists.h"
#include "namet.h"
#include "nlists.h"
#include "repinfo.h"
#include "snames.h"
#include "stringt.h"
#include "uintp.h"
#include "fe.h"
#include "sinfo.h"
#include "einfo.h"
#include "hashtab.h"
#include "ada-tree.h"
#include "gigi.h"

/* Convention_Stdcall should be processed in a specific way on Windows targets
   only.  The macro below is a helper to avoid having to check for a Windows
   specific attribute throughout this unit.  */

#if TARGET_DLLIMPORT_DECL_ATTRIBUTES
#define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
#else
#define Has_Stdcall_Convention(E) (0)
#endif

/* These two variables are used to defer recursively expanding incomplete
   types while we are processing a record or subprogram type.  */

static int defer_incomplete_level = 0;
static struct incomplete
{
  struct incomplete *next;
  tree old_type;
  Entity_Id full_type;
} *defer_incomplete_list = 0;

/* These two variables are used to defer emission of debug information for
   nested incomplete record types  */

static int defer_debug_level = 0;
static tree defer_debug_incomplete_list;

/* A hash table used as to cache the result of annotate_value.  */
static GTY ((if_marked ("tree_int_map_marked_p"), param_is (struct tree_int_map)))
  htab_t annotate_value_cache;

static void copy_alias_set (tree, tree);
static tree substitution_list (Entity_Id, Entity_Id, tree, bool);
static bool allocatable_size_p (tree, bool);
static void prepend_attributes (Entity_Id, struct attrib **);
static tree elaborate_expression (Node_Id, Entity_Id, tree, bool, bool, bool);
static bool is_variable_size (tree);
static tree elaborate_expression_1 (Node_Id, Entity_Id, tree, tree,
                                    bool, bool);
static tree make_packable_type (tree);
static tree gnat_to_gnu_field (Entity_Id, tree, int, bool);
static bool same_discriminant_p (Entity_Id, Entity_Id);
static void components_to_record (tree, Node_Id, tree, int, bool, tree *,
                                  bool, bool, bool, bool);
static int compare_field_bitpos (const PTR, const PTR);
static Uint annotate_value (tree);
static void annotate_rep (Entity_Id, tree);
static tree compute_field_positions (tree, tree, tree, tree, unsigned int);
static tree validate_size (Uint, tree, Entity_Id, enum tree_code, bool, bool);
static void set_rm_size (Uint, tree, Entity_Id);
static tree make_type_from_size (tree, tree, bool);
static unsigned int validate_alignment (Uint, Entity_Id, unsigned int);
static void check_ok_for_atomic (tree, Entity_Id, bool);
static int  compatible_signatures_p (tree ftype1, tree ftype2);

/* Given GNAT_ENTITY, an entity in the incoming GNAT tree, return a
   GCC type corresponding to that entity.  GNAT_ENTITY is assumed to
   refer to an Ada type.  */

tree
gnat_to_gnu_type (Entity_Id gnat_entity)
{
  tree gnu_decl;

  /* The back end never attempts to annotate generic types */
  if (Is_Generic_Type (gnat_entity) && type_annotate_only)
     return void_type_node;

  /* Convert the ada entity type into a GCC TYPE_DECL node.  */
  gnu_decl = gnat_to_gnu_entity (gnat_entity, NULL_TREE, 0);
  gcc_assert (TREE_CODE (gnu_decl) == TYPE_DECL);
  return TREE_TYPE (gnu_decl);
}
\f
/* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
   entity, this routine returns the equivalent GCC tree for that entity
   (an ..._DECL node) and associates the ..._DECL node with the input GNAT
   defining identifier.

   If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
   initial value (in GCC tree form). This is optional for variables.
   For renamed entities, GNU_EXPR gives the object being renamed.

   DEFINITION is nonzero if this call is intended for a definition.  This is
   used for separate compilation where it necessary to know whether an
   external declaration or a definition should be created if the GCC equivalent
   was not created previously.  The value of 1 is normally used for a nonzero
   DEFINITION, but a value of 2 is used in special circumstances, defined in
   the code.  */

tree
gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
{
  tree gnu_entity_id;
  tree gnu_type = NULL_TREE;
  /* Contains the gnu XXXX_DECL tree node which is equivalent to the input
     GNAT tree. This node will be associated with the GNAT node by calling
     the save_gnu_tree routine at the end of the `switch' statement.  */
  tree gnu_decl = NULL_TREE;
  /* true if we have already saved gnu_decl as a gnat association.  */
  bool saved = false;
  /* Nonzero if we incremented defer_incomplete_level.  */
  bool this_deferred = false;
  /* Nonzero if we incremented defer_debug_level.  */
  bool debug_deferred = false;
  /* Nonzero if we incremented force_global.  */
  bool this_global = false;
  /* Nonzero if we should check to see if elaborated during processing.  */
  bool maybe_present = false;
  /* Nonzero if we made GNU_DECL and its type here.  */
  bool this_made_decl = false;
  struct attrib *attr_list = NULL;
  bool debug_info_p = (Needs_Debug_Info (gnat_entity)
                       || debug_info_level == DINFO_LEVEL_VERBOSE);
  Entity_Kind kind = Ekind (gnat_entity);
  Entity_Id gnat_temp;
  unsigned int esize
    = ((Known_Esize (gnat_entity)
        && UI_Is_In_Int_Range (Esize (gnat_entity)))
       ? MIN (UI_To_Int (Esize (gnat_entity)),
              IN (kind, Float_Kind)
              ? fp_prec_to_size (LONG_DOUBLE_TYPE_SIZE)
              : IN (kind, Access_Kind) ? POINTER_SIZE * 2
              : LONG_LONG_TYPE_SIZE)
       : LONG_LONG_TYPE_SIZE);
  tree gnu_size = 0;
  bool imported_p
    = (Is_Imported (gnat_entity) && No (Address_Clause (gnat_entity)));
  unsigned int align = 0;

  /* Since a use of an Itype is a definition, process it as such if it
     is not in a with'ed unit. */

  if (!definition && Is_Itype (gnat_entity)
      && !present_gnu_tree (gnat_entity)
      && In_Extended_Main_Code_Unit (gnat_entity))
    {
      /* Ensure that we are in a subprogram mentioned in the Scope
         chain of this entity, our current scope is global,
         or that we encountered a task or entry (where we can't currently
         accurately check scoping).  */
      if (!current_function_decl
          || DECL_ELABORATION_PROC_P (current_function_decl))
        {
          process_type (gnat_entity);
          return get_gnu_tree (gnat_entity);
        }

      for (gnat_temp = Scope (gnat_entity);
           Present (gnat_temp); gnat_temp = Scope (gnat_temp))
        {
          if (Is_Type (gnat_temp))
            gnat_temp = Underlying_Type (gnat_temp);

          if (Ekind (gnat_temp) == E_Subprogram_Body)
            gnat_temp
              = Corresponding_Spec (Parent (Declaration_Node (gnat_temp)));

          if (IN (Ekind (gnat_temp), Subprogram_Kind)
              && Present (Protected_Body_Subprogram (gnat_temp)))
            gnat_temp = Protected_Body_Subprogram (gnat_temp);

          if (Ekind (gnat_temp) == E_Entry
              || Ekind (gnat_temp) == E_Entry_Family
              || Ekind (gnat_temp) == E_Task_Type
              || (IN (Ekind (gnat_temp), Subprogram_Kind)
                  && present_gnu_tree (gnat_temp)
                  && (current_function_decl
                      == gnat_to_gnu_entity (gnat_temp, NULL_TREE, 0))))
            {
              process_type (gnat_entity);
              return get_gnu_tree (gnat_entity);
            }
        }

      /* This abort means the entity "gnat_entity" has an incorrect scope,
         i.e. that its scope does not correspond to the subprogram in which
         it is declared */
      gcc_unreachable ();
    }

  /* If this is entity 0, something went badly wrong.  */
  gcc_assert (Present (gnat_entity));

  /* If we've already processed this entity, return what we got last time.
     If we are defining the node, we should not have already processed it.
     In that case, we will abort below when we try to save a new GCC tree for
     this object.   We also need to handle the case of getting a dummy type
     when a Full_View exists.  */

  if (present_gnu_tree (gnat_entity)
      && (!definition || (Is_Type (gnat_entity) && imported_p)))
    {
      gnu_decl = get_gnu_tree (gnat_entity);

      if (TREE_CODE (gnu_decl) == TYPE_DECL
          && TYPE_IS_DUMMY_P (TREE_TYPE (gnu_decl))
          && IN (kind, Incomplete_Or_Private_Kind)
          && Present (Full_View (gnat_entity)))
        {
          gnu_decl = gnat_to_gnu_entity (Full_View (gnat_entity),
                                         NULL_TREE, 0);

          save_gnu_tree (gnat_entity, NULL_TREE, false);
          save_gnu_tree (gnat_entity, gnu_decl, false);
        }

      return gnu_decl;
    }

  /* If this is a numeric or enumeral type, or an access type, a nonzero
     Esize must be specified unless it was specified by the programmer.  */
  gcc_assert (!Unknown_Esize (gnat_entity)
              || Has_Size_Clause (gnat_entity)
              || (!IN (kind, Numeric_Kind) && !IN (kind, Enumeration_Kind)
                  && (!IN (kind, Access_Kind)
                      || kind == E_Access_Protected_Subprogram_Type
                      || kind == E_Anonymous_Access_Protected_Subprogram_Type
                      || kind == E_Access_Subtype)));

  /* Likewise, RM_Size must be specified for all discrete and fixed-point
     types.  */
  gcc_assert (!IN (kind, Discrete_Or_Fixed_Point_Kind)
              || !Unknown_RM_Size (gnat_entity));

  /* Get the name of the entity and set up the line number and filename of
     the original definition for use in any decl we make.  */
  gnu_entity_id = get_entity_name (gnat_entity);
  Sloc_to_locus (Sloc (gnat_entity), &input_location);

  /* If we get here, it means we have not yet done anything with this
     entity.  If we are not defining it here, it must be external,
     otherwise we should have defined it already.  */
  gcc_assert (definition || Is_Public (gnat_entity) || type_annotate_only
              || kind == E_Discriminant || kind == E_Component
              || kind == E_Label
              || (kind == E_Constant && Present (Full_View (gnat_entity)))
              || IN (kind, Type_Kind));

  /* For cases when we are not defining (i.e., we are referencing from
     another compilation unit) Public entities, show we are at global level
     for the purpose of computing scopes.  Don't do this for components or
     discriminants since the relevant test is whether or not the record is
     being defined.  But do this for Imported functions or procedures in
     all cases.  */
  if ((!definition && Is_Public (gnat_entity)
       && !Is_Statically_Allocated (gnat_entity)
       && kind != E_Discriminant && kind != E_Component)
      || (Is_Imported (gnat_entity)
          && (kind == E_Function || kind == E_Procedure)))
    force_global++, this_global = true;

  /* Handle any attributes directly attached to the entity.  */
  if (Has_Gigi_Rep_Item (gnat_entity))
    prepend_attributes (gnat_entity, &attr_list);

  /* Machine_Attributes on types are expected to be propagated to subtypes.
     The corresponding Gigi_Rep_Items are only attached to the first subtype
     though, so we handle the propagation here.  */
  if (Is_Type (gnat_entity) && Base_Type (gnat_entity) != gnat_entity
      && !Is_First_Subtype (gnat_entity)
      && Has_Gigi_Rep_Item (First_Subtype (Base_Type (gnat_entity))))
    prepend_attributes (First_Subtype (Base_Type (gnat_entity)), &attr_list);

  switch (kind)
    {
    case E_Constant:
      /* If this is a use of a deferred constant, get its full
         declaration.  */
      if (!definition && Present (Full_View (gnat_entity)))
        {
          gnu_decl = gnat_to_gnu_entity (Full_View (gnat_entity),
                                         gnu_expr, 0);
          saved = true;
          break;
        }

      /* If we have an external constant that we are not defining,
         get the expression that is was defined to represent.  We
         may throw that expression away later if it is not a
         constant.
         Do not retrieve the expression if it is an aggregate, because
         in complex instantiation contexts it may not be expanded  */

      if (!definition
          && Present (Expression (Declaration_Node (gnat_entity)))
          && !No_Initialization (Declaration_Node (gnat_entity))
          && (Nkind (Expression   (Declaration_Node (gnat_entity)))
              != N_Aggregate))
        gnu_expr = gnat_to_gnu (Expression (Declaration_Node (gnat_entity)));

      /* Ignore deferred constant definitions; they are processed fully in the
         front-end.  For deferred constant references, get the full
         definition.  On the other hand, constants that are renamings are
         handled like variable renamings.  If No_Initialization is set, this is
         not a deferred constant but a constant whose value is built
         manually.  */

      if (definition && !gnu_expr
          && !No_Initialization (Declaration_Node (gnat_entity))
          && No (Renamed_Object (gnat_entity)))
        {
          gnu_decl = error_mark_node;
          saved = true;
          break;
        }
      else if (!definition && IN (kind, Incomplete_Or_Private_Kind)
               && Present (Full_View (gnat_entity)))
        {
          gnu_decl =  gnat_to_gnu_entity (Full_View (gnat_entity),
                                          NULL_TREE, 0);
          saved = true;
          break;
        }

      goto object;

    case E_Exception:
      /* We used to special case VMS exceptions here to directly map them to
         their associated condition code.  Since this code had to be masked
         dynamically to strip off the severity bits, this caused trouble in
         the GCC/ZCX case because the "type" pointers we store in the tables
         have to be static.  We now don't special case here anymore, and let
         the regular processing take place, which leaves us with a regular
         exception data object for VMS exceptions too.  The condition code
         mapping is taken care of by the front end and the bitmasking by the
         runtime library.   */
      goto object;

    case E_Discriminant:
    case E_Component:
      {
        /* The GNAT record where the component was defined. */
        Entity_Id gnat_record = Underlying_Type (Scope (gnat_entity));

        /* If the variable is an inherited record component (in the case of
           extended record types), just return the inherited entity, which
           must be a FIELD_DECL.  Likewise for discriminants.
           For discriminants of untagged records which have explicit
           stored discriminants, return the entity for the corresponding
           stored discriminant.  Also use Original_Record_Component
           if the record has a private extension.  */

        if (Present (Original_Record_Component (gnat_entity))
            && Original_Record_Component (gnat_entity) != gnat_entity)
          {
            gnu_decl
              = gnat_to_gnu_entity (Original_Record_Component (gnat_entity),
                                    gnu_expr, definition);
            saved = true;
            break;
          }

        /* If the enclosing record has explicit stored discriminants,
           then it is an untagged record.  If the Corresponding_Discriminant
           is not empty then this must be a renamed discriminant and its
           Original_Record_Component must point to the corresponding explicit
           stored discriminant (i.e., we should have taken the previous
           branch).  */

        else if (Present (Corresponding_Discriminant (gnat_entity))
                 && Is_Tagged_Type (gnat_record))
          {
            /* A tagged record has no explicit stored discriminants. */

            gcc_assert (First_Discriminant (gnat_record)
                       == First_Stored_Discriminant (gnat_record));
            gnu_decl
              = gnat_to_gnu_entity (Corresponding_Discriminant (gnat_entity),
                                    gnu_expr, definition);
            saved = true;
            break;
          }

        else if (Present (CR_Discriminant (gnat_entity))
                 && type_annotate_only)
          {
            gnu_decl = gnat_to_gnu_entity (CR_Discriminant (gnat_entity),
                                           gnu_expr, definition);
            saved = true;
            break;
          }

        /* If the enclosing record has explicit stored discriminants,
           then it is an untagged record. If the Corresponding_Discriminant
           is not empty then this must be a renamed discriminant and its
           Original_Record_Component must point to the corresponding explicit
           stored discriminant (i.e., we should have taken the first
           branch).  */

        else if (Present (Corresponding_Discriminant (gnat_entity))
                 && (First_Discriminant (gnat_record)
                     != First_Stored_Discriminant (gnat_record)))
          gcc_unreachable ();

        /* Otherwise, if we are not defining this and we have no GCC type
           for the containing record, make one for it.  Then we should
           have made our own equivalent.  */
        else if (!definition && !present_gnu_tree (gnat_record))
          {
            /* ??? If this is in a record whose scope is a protected
               type and we have an Original_Record_Component, use it.
               This is a workaround for major problems in protected type
               handling.  */

            Entity_Id Scop = Scope (Scope (gnat_entity));
            if ((Is_Protected_Type (Scop)
                || (Is_Private_Type (Scop)
                     && Present (Full_View (Scop))
                     && Is_Protected_Type (Full_View (Scop))))
                && Present (Original_Record_Component (gnat_entity)))
              {
                gnu_decl
                  = gnat_to_gnu_entity (Original_Record_Component
                                        (gnat_entity),
                                        gnu_expr, 0);
                saved = true;
                break;
              }

            gnat_to_gnu_entity (Scope (gnat_entity), NULL_TREE, 0);
            gnu_decl = get_gnu_tree (gnat_entity);
            saved = true;
            break;
          }

        else
          /* Here we have no GCC type and this is a reference rather than a
             definition. This should never happen. Most likely the cause is a
             reference before declaration in the gnat tree for gnat_entity.  */
          gcc_unreachable ();
      }

    case E_Loop_Parameter:
    case E_Out_Parameter:
    case E_Variable:

      /* Simple variables, loop variables, OUT parameters, and exceptions.  */
    object:
      {
        bool used_by_ref = false;
        bool const_flag
          = ((kind == E_Constant || kind == E_Variable)
             && !Is_Statically_Allocated (gnat_entity)
             && Is_True_Constant (gnat_entity)
             && (((Nkind (Declaration_Node (gnat_entity))
                   == N_Object_Declaration)
                  && Present (Expression (Declaration_Node (gnat_entity))))
                 || Present (Renamed_Object (gnat_entity))));
        bool inner_const_flag = const_flag;
        bool static_p = Is_Statically_Allocated (gnat_entity);
        bool mutable_p = false;
        tree gnu_ext_name = NULL_TREE;
        tree renamed_obj = NULL_TREE;

        if (Present (Renamed_Object (gnat_entity)) && !definition)
          {
            if (kind == E_Exception)
              gnu_expr = gnat_to_gnu_entity (Renamed_Entity (gnat_entity),
                                             NULL_TREE, 0);
            else
              gnu_expr = gnat_to_gnu (Renamed_Object (gnat_entity));
          }

        /* Get the type after elaborating the renamed object.  */
        gnu_type = gnat_to_gnu_type (Etype (gnat_entity));

        /* If this is a loop variable, its type should be the base type.
           This is because the code for processing a loop determines whether
           a normal loop end test can be done by comparing the bounds of the
           loop against those of the base type, which is presumed to be the
           size used for computation.  But this is not correct when the size
           of the subtype is smaller than the type.  */
        if (kind == E_Loop_Parameter)
          gnu_type = get_base_type (gnu_type);

        /* Reject non-renamed objects whose types are unconstrained arrays or
           any object whose type is a dummy type or VOID_TYPE. */

        if ((TREE_CODE (gnu_type) == UNCONSTRAINED_ARRAY_TYPE
             && No (Renamed_Object (gnat_entity)))
            || TYPE_IS_DUMMY_P (gnu_type)
            || TREE_CODE (gnu_type) == VOID_TYPE)
          {
            gcc_assert (type_annotate_only);
            if (this_global)
              force_global--;
            return error_mark_node;
          }

        /* If an alignment is specified, use it if valid.   Note that
           exceptions are objects but don't have alignments.  We must do this
           before we validate the size, since the alignment can affect the
           size.  */
        if (kind != E_Exception && Known_Alignment (gnat_entity))
          {
            gcc_assert (Present (Alignment (gnat_entity)));
            align = validate_alignment (Alignment (gnat_entity), gnat_entity,
                                        TYPE_ALIGN (gnu_type));
            gnu_type = maybe_pad_type (gnu_type, NULL_TREE, align,
                                       gnat_entity, "PAD", 0, definition, 1);
          }

        /* If we are defining the object, see if it has a Size value and
           validate it if so. If we are not defining the object and a Size
           clause applies, simply retrieve the value. We don't want to ignore
           the clause and it is expected to have been validated already.  Then
           get the new type, if any.  */
        if (definition)
          gnu_size = validate_size (Esize (gnat_entity), gnu_type,
                                    gnat_entity, VAR_DECL, false,
                                    Has_Size_Clause (gnat_entity));
        else if (Has_Size_Clause (gnat_entity))
          gnu_size = UI_To_gnu (Esize (gnat_entity), bitsizetype);

        if (gnu_size)
          {
            gnu_type
              = make_type_from_size (gnu_type, gnu_size,
                                     Has_Biased_Representation (gnat_entity));

            if (operand_equal_p (TYPE_SIZE (gnu_type), gnu_size, 0))
              gnu_size = NULL_TREE;
          }

        /* If this object has self-referential size, it must be a record with
           a default value.  We are supposed to allocate an object of the
           maximum size in this case unless it is a constant with an
           initializing expression, in which case we can get the size from
           that.  Note that the resulting size may still be a variable, so
           this may end up with an indirect allocation.  */

        if (No (Renamed_Object (gnat_entity))
            && CONTAINS_PLACEHOLDER_P (TYPE_SIZE (gnu_type)))
          {
            if (gnu_expr && kind == E_Constant)
              gnu_size
                = SUBSTITUTE_PLACEHOLDER_IN_EXPR
                  (TYPE_SIZE (TREE_TYPE (gnu_expr)), gnu_expr);

            /* We may have no GNU_EXPR because No_Initialization is
               set even though there's an Expression.  */
            else if (kind == E_Constant
                     && (Nkind (Declaration_Node (gnat_entity))
                         == N_Object_Declaration)
                     && Present (Expression (Declaration_Node (gnat_entity))))
              gnu_size
                = TYPE_SIZE (gnat_to_gnu_type
                             (Etype
                              (Expression (Declaration_Node (gnat_entity)))));
            else
              {
                gnu_size = max_size (TYPE_SIZE (gnu_type), true);
                mutable_p = true;
              }
          }

        /* If the size is zero bytes, make it one byte since some linkers have
           trouble with zero-sized objects.  If the object will have a
           template, that will make it nonzero so don't bother.  Also avoid
           doing that for an object renaming or an object with an address
           clause, as we would lose useful information on the view size
           (e.g. for null array slices) and we are not allocating the object
           here anyway.  */
        if (((gnu_size && integer_zerop (gnu_size))
             || (TYPE_SIZE (gnu_type) && integer_zerop (TYPE_SIZE (gnu_type))))
            && (!Is_Constr_Subt_For_UN_Aliased (Etype (gnat_entity))
                || !Is_Array_Type (Etype (gnat_entity)))
            && !Present (Renamed_Object (gnat_entity))
            && !Present (Address_Clause (gnat_entity)))
          gnu_size = bitsize_unit_node;

        /* If this is an atomic object with no specified size and alignment,
           but where the size of the type is a constant, set the alignment to
           the lowest power of two greater than the size, or to the
           biggest meaningful alignment, whichever is smaller.  */

        if (Is_Atomic (gnat_entity) && !gnu_size && align == 0
            && TREE_CODE (TYPE_SIZE (gnu_type)) == INTEGER_CST)
          {
            if (!host_integerp (TYPE_SIZE (gnu_type), 1)
                || 0 <= compare_tree_int (TYPE_SIZE (gnu_type),
                                          BIGGEST_ALIGNMENT))
              align = BIGGEST_ALIGNMENT;
            else
              align = ((unsigned int) 1
                       << (floor_log2 (tree_low_cst
                                       (TYPE_SIZE (gnu_type), 1) - 1)
                           + 1));
          }

        /* If the object is set to have atomic components, find the component
           type and validate it.

           ??? Note that we ignore Has_Volatile_Components on objects; it's
           not at all clear what to do in that case. */

        if (Has_Atomic_Components (gnat_entity))
          {
            tree gnu_inner = (TREE_CODE (gnu_type) == ARRAY_TYPE
                              ? TREE_TYPE (gnu_type) : gnu_type);

            while (TREE_CODE (gnu_inner) == ARRAY_TYPE
                   && TYPE_MULTI_ARRAY_P (gnu_inner))
              gnu_inner = TREE_TYPE (gnu_inner);

            check_ok_for_atomic (gnu_inner, gnat_entity, true);
          }

        /* Now check if the type of the object allows atomic access.  Note
           that we must test the type, even if this object has size and
           alignment to allow such access, because we will be going
           inside the padded record to assign to the object.  We could fix
           this by always copying via an intermediate value, but it's not
           clear it's worth the effort.  */
        if (Is_Atomic (gnat_entity))
          check_ok_for_atomic (gnu_type, gnat_entity, false);

        /* If this is an aliased object with an unconstrained nominal subtype,
           make a type that includes the template.  */
        if (Is_Constr_Subt_For_UN_Aliased (Etype (gnat_entity))
            && Is_Array_Type (Etype (gnat_entity))
            && !type_annotate_only)
        {
          tree gnu_fat
            = TREE_TYPE (gnat_to_gnu_type (Base_Type (Etype (gnat_entity))));

          gnu_type
            = build_unc_object_type_from_ptr (gnu_fat, gnu_type,
                                     concat_id_with_name (gnu_entity_id,
                                                          "UNC"));
        }

#ifdef MINIMUM_ATOMIC_ALIGNMENT
        /* If the size is a constant and no alignment is specified, force
           the alignment to be the minimum valid atomic alignment.  The
           restriction on constant size avoids problems with variable-size
           temporaries; if the size is variable, there's no issue with
           atomic access.  Also don't do this for a constant, since it isn't
           necessary and can interfere with constant replacement.  Finally,
           do not do it for Out parameters since that creates an
           size inconsistency with In parameters.  */
        if (align == 0 && MINIMUM_ATOMIC_ALIGNMENT > TYPE_ALIGN (gnu_type)
            && !FLOAT_TYPE_P (gnu_type)
            && !const_flag && No (Renamed_Object (gnat_entity))
            && !imported_p && No (Address_Clause (gnat_entity))
            && kind != E_Out_Parameter
            && (gnu_size ? TREE_CODE (gnu_size) == INTEGER_CST
                : TREE_CODE (TYPE_SIZE (gnu_type)) == INTEGER_CST))
          align = MINIMUM_ATOMIC_ALIGNMENT;
#endif

        /* Make a new type with the desired size and alignment, if needed. */
        gnu_type = maybe_pad_type (gnu_type, gnu_size, align, gnat_entity,
                                   "PAD", false, definition, true);

        /* Make a volatile version of this object's type if we are to
           make the object volatile.  Note that 13.3(19) says that we
           should treat other types of objects as volatile as well.  */
        if ((Treat_As_Volatile (gnat_entity)
             || Is_Exported (gnat_entity)
             || Is_Imported (gnat_entity))
            && !TYPE_VOLATILE (gnu_type))
          gnu_type = build_qualified_type (gnu_type,
                                           (TYPE_QUALS (gnu_type)
                                            | TYPE_QUAL_VOLATILE));

        /* Convert the expression to the type of the object except in the
           case where the object's type is unconstrained or the object's type
           is a padded record whose field is of self-referential size.  In
           the former case, converting will generate unnecessary evaluations
           of the CONSTRUCTOR to compute the size and in the latter case, we
           want to only copy the actual data.  */
        if (gnu_expr
            && TREE_CODE (gnu_type) != UNCONSTRAINED_ARRAY_TYPE
            && !CONTAINS_PLACEHOLDER_P (TYPE_SIZE (gnu_type))
            && !(TREE_CODE (gnu_type) == RECORD_TYPE
                 && TYPE_IS_PADDING_P (gnu_type)
                 && (CONTAINS_PLACEHOLDER_P
                     (TYPE_SIZE (TREE_TYPE (TYPE_FIELDS (gnu_type)))))))
          gnu_expr = convert (gnu_type, gnu_expr);

        /* See if this is a renaming, and handle appropriately depending on
           what is renamed and in which context.  There are three major
           cases:

           1/ This is a constant renaming and we can just make an object
              with what is renamed as its initial value,

           2/ We can reuse a stabilized version of what is renamed in place
              of the renaming,

           3/ If neither 1 or 2 applies, we make the renaming entity a constant
              pointer to what is being renamed.  */

        if (Present (Renamed_Object (gnat_entity)))
          {
            /* If the renamed object had padding, strip off the reference
               to the inner object and reset our type.  */
            if (TREE_CODE (gnu_expr) == COMPONENT_REF
                && (TREE_CODE (TREE_TYPE (TREE_OPERAND (gnu_expr, 0)))
                    == RECORD_TYPE)
                && (TYPE_IS_PADDING_P
                    (TREE_TYPE (TREE_OPERAND (gnu_expr, 0)))))
              {
                gnu_expr = TREE_OPERAND (gnu_expr, 0);
                gnu_type = TREE_TYPE (gnu_expr);
              }

            /* Case 1: If this is a constant renaming, treat it as a normal
               object whose initial value is what is being renamed.  We cannot
               do this if the type is unconstrained or class-wide.  */
            if (const_flag
                && !TREE_SIDE_EFFECTS (gnu_expr)
                && TREE_CODE (gnu_type) != UNCONSTRAINED_ARRAY_TYPE
                && TYPE_MODE (gnu_type) != BLKmode
                && Ekind (Etype (gnat_entity)) != E_Class_Wide_Type
                && !Is_Array_Type (Etype (gnat_entity)))
              ;

            /* Otherwise, see if we can proceed with a stabilized version of
               the renamed entity or if we need to make a pointer.  */
            else
              {
                bool stabilized = false;
                tree maybe_stable_expr = NULL_TREE;

                /* Case 2: If the renaming entity need not be materialized and
                   the renamed expression is something we can stabilize, use
                   that for the renaming.  At the global level, we can only do
                   this if we know no SAVE_EXPRs need be made, because the
                   expression we return might be used in arbitrary conditional
                   branches so we must force the SAVE_EXPRs evaluation
                   immediately and this requires a function context.  */
                if (!Materialize_Entity (gnat_entity)
                    && (!global_bindings_p ()
                        || (staticp (gnu_expr)
                            && !TREE_SIDE_EFFECTS (gnu_expr))))
                  {
                    maybe_stable_expr
                      = maybe_stabilize_reference (gnu_expr, true, false,
                                                   &stabilized);

                    if (stabilized)
                      {
                        gnu_decl = maybe_stable_expr;
                        save_gnu_tree (gnat_entity, gnu_decl, true);
                        saved = true;
                        break;
                      }

                    /* The stabilization failed.  Keep maybe_stable_expr
                       untouched here to let the pointer case below know
                       about that failure.  */
                  }

                /* Case 3: Make this into a constant pointer to the object we
                   are to rename and attach the object to the pointer if it is
                   an lvalue that can be stabilized.

                   From the proper scope, attached objects will be referenced
                   directly instead of indirectly via the pointer to avoid
                   subtle aliasing problems with non addressable entities.
                   They have to be stable because we must not evaluate the
                   variables in the expression every time the renaming is used.
                   They also have to be lvalues because the context in which
                   they are reused sometimes requires so.  We call pointers
                   with an attached object "renaming" pointers.

                   In the rare cases where we cannot stabilize the renamed
                   object, we just make a "bare" pointer, and the renamed
                   entity is always accessed indirectly through it.  */
                {
                  inner_const_flag = TREE_READONLY (gnu_expr);
                  const_flag = true;
                  gnu_type = build_reference_type (gnu_type);

                  /* If a previous attempt at unrestricted stabilization
                     failed, there is no point trying again and we can reuse
                     the result without attaching it to the pointer.  In this
                     case it will only be used as the initializing expression
                     of the pointer and thus needs no special treatment with
                     regard to multiple evaluations.  */
                  if (maybe_stable_expr)
                    ;

                  /* Otherwise, try to stabilize now, restricting to lvalues
                     only, and attach the expression to the pointer if the
                     stabilization succeeds.

                     Note that this might introduce SAVE_EXPRs and we don't
                     check whether we're at the global level or not.  This is
                     fine since we are building a pointer initializer and
                     neither the pointer nor the initializing expression can
                     be accessed before the pointer elaboration has taken
                     place in a correct program.

                     SAVE_EXPRs will be evaluated at the right spots by either
                     create_var_decl->expand_decl_init for the non-global case
                     or build_unit_elab for the global case, and will be
                     attached to the elaboration procedure by the RTL expander
                     in the latter case.  We have no need to force an early
                     evaluation here.  */
                  else
                    {
                      maybe_stable_expr
                        = maybe_stabilize_reference (gnu_expr, true, true,
                                                     &stabilized);

                      if (stabilized)
                        renamed_obj = maybe_stable_expr;

                      /* Attaching is actually performed downstream, as soon
                         as we have a VAR_DECL for the pointer we make.  */
                    }

                  gnu_expr
                    = build_unary_op (ADDR_EXPR, gnu_type, maybe_stable_expr);

                  gnu_size = NULL_TREE;
                  used_by_ref = true;
                }
              }
          }

        /* If this is an aliased object whose nominal subtype is unconstrained,
           the object is a record that contains both the template and
           the object.  If there is an initializer, it will have already
           been converted to the right type, but we need to create the
           template if there is no initializer.  */
        else if (definition && TREE_CODE (gnu_type) == RECORD_TYPE
                 && (TYPE_CONTAINS_TEMPLATE_P (gnu_type)
                     /* Beware that padding might have been introduced
                        via maybe_pad_type above.  */
                     || (TYPE_IS_PADDING_P (gnu_type)
                         && TREE_CODE (TREE_TYPE (TYPE_FIELDS (gnu_type)))
                            == RECORD_TYPE
                         && TYPE_CONTAINS_TEMPLATE_P
                            (TREE_TYPE (TYPE_FIELDS (gnu_type)))))
                 && !gnu_expr)
          {
            tree template_field
              = TYPE_IS_PADDING_P (gnu_type)
                ? TYPE_FIELDS (TREE_TYPE (TYPE_FIELDS (gnu_type)))
                : TYPE_FIELDS (gnu_type);

            gnu_expr
              = gnat_build_constructor
              (gnu_type,
               tree_cons
               (template_field,
                build_template (TREE_TYPE (template_field),
                                TREE_TYPE (TREE_CHAIN (template_field)),
                                NULL_TREE),
                NULL_TREE));
          }

        /* If this is a pointer and it does not have an initializing
           expression, initialize it to NULL, unless the object is
           imported.  */
        if (definition
            && (POINTER_TYPE_P (gnu_type) || TYPE_FAT_POINTER_P (gnu_type))
            && !Is_Imported (gnat_entity) && !gnu_expr)
          gnu_expr = integer_zero_node;

        /* If we are defining the object and it has an Address clause we must
           get the address expression from the saved GCC tree for the
           object if the object has a Freeze_Node.  Otherwise, we elaborate
           the address expression here since the front-end has guaranteed
           in that case that the elaboration has no effects.  Note that
           only the latter mechanism is currently in use.  */
        if (definition && Present (Address_Clause (gnat_entity)))
          {
            tree gnu_address
              = (present_gnu_tree (gnat_entity) ? get_gnu_tree (gnat_entity)
                : gnat_to_gnu (Expression (Address_Clause (gnat_entity))));

            save_gnu_tree (gnat_entity, NULL_TREE, false);

            /* Ignore the size.  It's either meaningless or was handled
               above.  */
            gnu_size = NULL_TREE;
            /* Convert the type of the object to a reference type that can
               alias everything as per 13.3(19).  */
            gnu_type
              = build_reference_type_for_mode (gnu_type, ptr_mode, true);
            gnu_address = convert (gnu_type, gnu_address);
            used_by_ref = true;
            const_flag = !Is_Public (gnat_entity);

            /* If we don't have an initializing expression for the underlying
               variable, the initializing expression for the pointer is the
               specified address.  Otherwise, we have to make a COMPOUND_EXPR
               to assign both the address and the initial value.  */
            if (!gnu_expr)
              gnu_expr = gnu_address;
            else
              gnu_expr
                = build2 (COMPOUND_EXPR, gnu_type,
                          build_binary_op
                          (MODIFY_EXPR, NULL_TREE,
                           build_unary_op (INDIRECT_REF, NULL_TREE,
                                           gnu_address),
                           gnu_expr),
                          gnu_address);
          }

        /* If it has an address clause and we are not defining it, mark it
           as an indirect object.  Likewise for Stdcall objects that are
           imported.  */
        if ((!definition && Present (Address_Clause (gnat_entity)))
            || (Is_Imported (gnat_entity)
                && Has_Stdcall_Convention (gnat_entity)))
          {
            /* Convert the type of the object to a reference type that can
               alias everything as per 13.3(19).  */
            gnu_type
              = build_reference_type_for_mode (gnu_type, ptr_mode, true);
            gnu_size = NULL_TREE;

            gnu_expr = NULL_TREE;
            /* No point in taking the address of an initializing expression
               that isn't going to be used.  */

            used_by_ref = true;
          }

        /* If we are at top level and this object is of variable size,
           make the actual type a hidden pointer to the real type and
           make the initializer be a memory allocation and initialization.
           Likewise for objects we aren't defining (presumed to be
           external references from other packages), but there we do
           not set up an initialization.

           If the object's size overflows, make an allocator too, so that
           Storage_Error gets raised.  Note that we will never free
           such memory, so we presume it never will get allocated.  */

        if (!allocatable_size_p (TYPE_SIZE_UNIT (gnu_type),
                                 global_bindings_p () || !definition
                                 || static_p)
            || (gnu_size
                && ! allocatable_size_p (gnu_size,
                                         global_bindings_p () || !definition
                                         || static_p)))
          {
            gnu_type = build_reference_type (gnu_type);
            gnu_size = NULL_TREE;
            used_by_ref = true;
            const_flag = true;

            /* In case this was a aliased object whose nominal subtype is
               unconstrained, the pointer above will be a thin pointer and
               build_allocator will automatically make the template.

               If we have a template initializer only (that we made above),
               pretend there is none and rely on what build_allocator creates
               again anyway.  Otherwise (if we have a full initializer), get
               the data part and feed that to build_allocator.

               If we are elaborating a mutable object, tell build_allocator to
               ignore a possibly simpler size from the initializer, if any, as
               we must allocate the maximum possible size in this case.  */

            if (definition)
              {
                tree gnu_alloc_type = TREE_TYPE (gnu_type);

                if (TREE_CODE (gnu_alloc_type) == RECORD_TYPE
                    && TYPE_CONTAINS_TEMPLATE_P (gnu_alloc_type))
                  {
                    gnu_alloc_type
                      = TREE_TYPE (TREE_CHAIN (TYPE_FIELDS (gnu_alloc_type)));

                   if (TREE_CODE (gnu_expr) == CONSTRUCTOR
                       && 1 == VEC_length (constructor_elt,
                                            CONSTRUCTOR_ELTS (gnu_expr)))
                     gnu_expr = 0;
                   else
                     gnu_expr
                       = build_component_ref
                         (gnu_expr, NULL_TREE,
                          TREE_CHAIN (TYPE_FIELDS (TREE_TYPE (gnu_expr))),
                          false);
                  }

                if (TREE_CODE (TYPE_SIZE_UNIT (gnu_alloc_type)) == INTEGER_CST
                    && TREE_OVERFLOW (TYPE_SIZE_UNIT (gnu_alloc_type))
                    && !Is_Imported (gnat_entity))
                  post_error ("Storage_Error will be raised at run-time?",
                              gnat_entity);

                gnu_expr = build_allocator (gnu_alloc_type, gnu_expr, gnu_type,
                                            0, 0, gnat_entity, mutable_p);
              }
            else
              {
                gnu_expr = NULL_TREE;
                const_flag = false;
              }
          }

        /* If this object would go into the stack and has an alignment
           larger than the default largest alignment, make a variable
           to hold the "aligning type" with a modified initial value,
           if any, then point to it and make that the value of this
           variable, which is now indirect.  */
        if (!global_bindings_p () && !static_p && definition
            && !imported_p && TYPE_ALIGN (gnu_type) > BIGGEST_ALIGNMENT)
          {
            tree gnu_new_type
              = make_aligning_type (gnu_type, TYPE_ALIGN (gnu_type),
                                    TYPE_SIZE_UNIT (gnu_type));
            tree gnu_new_var;

            gnu_new_var
              = create_var_decl (create_concat_name (gnat_entity, "ALIGN"),
                                 NULL_TREE, gnu_new_type, NULL_TREE, false,
                                 false, false, false, NULL, gnat_entity);

            if (gnu_expr)
              add_stmt_with_node
                (build_binary_op (MODIFY_EXPR, NULL_TREE,
                                  build_component_ref
                                  (gnu_new_var, NULL_TREE,
                                   TYPE_FIELDS (gnu_new_type), false),
                                  gnu_expr),
                 gnat_entity);

            gnu_type = build_reference_type (gnu_type);
            gnu_expr
              = build_unary_op
                (ADDR_EXPR, gnu_type,
                 build_component_ref (gnu_new_var, NULL_TREE,
                                      TYPE_FIELDS (gnu_new_type), false));

            gnu_size = NULL_TREE;
            used_by_ref = true;
            const_flag = true;
          }

        if (const_flag)
          gnu_type = build_qualified_type (gnu_type, (TYPE_QUALS (gnu_type)
                                                      | TYPE_QUAL_CONST));

        /* Convert the expression to the type of the object except in the
           case where the object's type is unconstrained or the object's type
           is a padded record whose field is of self-referential size.  In
           the former case, converting will generate unnecessary evaluations
           of the CONSTRUCTOR to compute the size and in the latter case, we
           want to only copy the actual data.  */
        if (gnu_expr
            && TREE_CODE (gnu_type) != UNCONSTRAINED_ARRAY_TYPE
            && !CONTAINS_PLACEHOLDER_P (TYPE_SIZE (gnu_type))
            && !(TREE_CODE (gnu_type) == RECORD_TYPE
                 && TYPE_IS_PADDING_P (gnu_type)
                 && (CONTAINS_PLACEHOLDER_P
                     (TYPE_SIZE (TREE_TYPE (TYPE_FIELDS (gnu_type)))))))
          gnu_expr = convert (gnu_type, gnu_expr);

        /* If this name is external or there was a name specified, use it,
           unless this is a VMS exception object since this would conflict
           with the symbol we need to export in addition.  Don't use the
           Interface_Name if there is an address clause (see CD30005).  */
        if (!Is_VMS_Exception (gnat_entity)
            && ((Present (Interface_Name (gnat_entity))
                 && No (Address_Clause (gnat_entity)))
                || (Is_Public (gnat_entity)
                    && (!Is_Imported (gnat_entity)
                        || Is_Exported (gnat_entity)))))
          gnu_ext_name = create_concat_name (gnat_entity, 0);

        /* If this is constant initialized to a static constant and the
           object has an aggregate type, force it to be statically
           allocated. */
        if (const_flag && gnu_expr && TREE_CONSTANT (gnu_expr)
            && host_integerp (TYPE_SIZE_UNIT (gnu_type), 1)
            && (AGGREGATE_TYPE_P (gnu_type)
                && !(TREE_CODE (gnu_type) == RECORD_TYPE
                     && TYPE_IS_PADDING_P (gnu_type))))
          static_p = true;

        gnu_decl = create_var_decl (gnu_entity_id, gnu_ext_name, gnu_type,
                                    gnu_expr, const_flag,
                                    Is_Public (gnat_entity),
                                    imported_p || !definition,
                                    static_p, attr_list, gnat_entity);
        DECL_BY_REF_P (gnu_decl) = used_by_ref;
        DECL_POINTS_TO_READONLY_P (gnu_decl) = used_by_ref && inner_const_flag;
        if (TREE_CODE (gnu_decl) == VAR_DECL && renamed_obj)
          {
            SET_DECL_RENAMED_OBJECT (gnu_decl, renamed_obj);
            if (global_bindings_p ())
              {
                DECL_RENAMING_GLOBAL_P (gnu_decl) = 1;
                record_global_renaming_pointer (gnu_decl);
              }
          }

        if (definition && DECL_SIZE (gnu_decl)
            && get_block_jmpbuf_decl ()
            && (TREE_CODE (DECL_SIZE (gnu_decl)) != INTEGER_CST
                || (flag_stack_check && !STACK_CHECK_BUILTIN
                    && 0 < compare_tree_int (DECL_SIZE_UNIT (gnu_decl),
                                             STACK_CHECK_MAX_VAR_SIZE))))
          add_stmt_with_node (build_call_1_expr
                              (update_setjmp_buf_decl,
                               build_unary_op (ADDR_EXPR, NULL_TREE,
                                               get_block_jmpbuf_decl ())),
                              gnat_entity);

        /* If this is a public constant or we're not optimizing and we're not
           making a VAR_DECL for it, make one just for export or debugger use.
           Likewise if the address is taken or if either the object or type is
           aliased.  Make an external declaration for a reference, unless this
           is a Standard entity since there no real symbol at the object level
           for these.  */
        if (TREE_CODE (gnu_decl) == CONST_DECL
            && (definition || Sloc (gnat_entity) > Standard_Location)
            && (Is_Public (gnat_entity)
                || optimize == 0
                || Address_Taken (gnat_entity)
                || Is_Aliased (gnat_entity)
                || Is_Aliased (Etype (gnat_entity))))
          {
            tree gnu_corr_var
              = create_true_var_decl (gnu_entity_id, gnu_ext_name, gnu_type,
                                      gnu_expr, true, Is_Public (gnat_entity),
                                      !definition, static_p, NULL,
                                      gnat_entity);

            SET_DECL_CONST_CORRESPONDING_VAR (gnu_decl, gnu_corr_var);
          }

        /* If this is declared in a block that contains a block with an
           exception handler, we must force this variable in memory to
           suppress an invalid optimization.  */
        if (Has_Nested_Block_With_Handler (Scope (gnat_entity))
            && Exception_Mechanism != Back_End_Exceptions)
          TREE_ADDRESSABLE (gnu_decl) = 1;

        /* Back-annotate the Alignment of the object if not already in the
           tree.  Likewise for Esize if the object is of a constant size.
           But if the "object" is actually a pointer to an object, the
           alignment and size are the same as the type, so don't back-annotate
           the values for the pointer.  */
        if (!used_by_ref && Unknown_Alignment (gnat_entity))
          Set_Alignment (gnat_entity,
                         UI_From_Int (DECL_ALIGN (gnu_decl) / BITS_PER_UNIT));

        if (!used_by_ref && Unknown_Esize (gnat_entity)
            && DECL_SIZE (gnu_decl))
          {
            tree gnu_back_size = DECL_SIZE (gnu_decl);

            if (TREE_CODE (TREE_TYPE (gnu_decl)) == RECORD_TYPE
                && TYPE_CONTAINS_TEMPLATE_P (TREE_TYPE (gnu_decl)))
              gnu_back_size
                = TYPE_SIZE (TREE_TYPE (TREE_CHAIN
                                        (TYPE_FIELDS (TREE_TYPE (gnu_decl)))));

            Set_Esize (gnat_entity, annotate_value (gnu_back_size));
          }
      }
      break;

    case E_Void:
      /* Return a TYPE_DECL for "void" that we previously made.  */
      gnu_decl = void_type_decl_node;
      break;

    case E_Enumeration_Type:
      /* A special case, for the types Character and Wide_Character in
         Standard, we do not list all the literals. So if the literals
         are not specified, make this an unsigned type.  */
      if (No (First_Literal (gnat_entity)))
        {
          gnu_type = make_unsigned_type (esize);
          TYPE_NAME (gnu_type) = gnu_entity_id;

          /* Set the TYPE_STRING_FLAG for Ada Character and
             Wide_Character types. This is needed by the dwarf-2 debug writer to
             distinguish between unsigned integer types and character types.  */
          TYPE_STRING_FLAG (gnu_type) = 1;
          break;
        }

      /* Normal case of non-character type, or non-Standard character type */
      {
        /* Here we have a list of enumeral constants in First_Literal.
           We make a CONST_DECL for each and build into GNU_LITERAL_LIST
           the list to be places into TYPE_FIELDS.  Each node in the list
           is a TREE_LIST node whose TREE_VALUE is the literal name
           and whose TREE_PURPOSE is the value of the literal.

           Esize contains the number of bits needed to represent the enumeral
           type, Type_Low_Bound also points to the first literal and
           Type_High_Bound points to the last literal.  */

        Entity_Id gnat_literal;
        tree gnu_literal_list = NULL_TREE;

        if (Is_Unsigned_Type (gnat_entity))
          gnu_type = make_unsigned_type (esize);
        else
          gnu_type = make_signed_type (esize);

        TREE_SET_CODE (gnu_type, ENUMERAL_TYPE);

        for (gnat_literal = First_Literal (gnat_entity);
             Present (gnat_literal);
             gnat_literal = Next_Literal (gnat_literal))
          {
            tree gnu_value = UI_To_gnu (Enumeration_Rep (gnat_literal),
                                        gnu_type);
            tree gnu_literal
              = create_var_decl (get_entity_name (gnat_literal), NULL_TREE,
                                 gnu_type, gnu_value, true, false, false,
                                 false, NULL, gnat_literal);

            save_gnu_tree (gnat_literal, gnu_literal, false);
            gnu_literal_list = tree_cons (DECL_NAME (gnu_literal),
                                          gnu_value, gnu_literal_list);
          }

        TYPE_VALUES (gnu_type) = nreverse (gnu_literal_list);

        /* Note that the bounds are updated at the end of this function
           because to avoid an infinite recursion when we get the bounds of
           this type, since those bounds are objects of this type.    */
      }
      break;

    case E_Signed_Integer_Type:
    case E_Ordinary_Fixed_Point_Type:
    case E_Decimal_Fixed_Point_Type:
      /* For integer types, just make a signed type the appropriate number
         of bits.  */
      gnu_type = make_signed_type (esize);
      break;

    case E_Modular_Integer_Type:
      /* For modular types, make the unsigned type of the proper number of
         bits and then set up the modulus, if required.  */
      {
        enum machine_mode mode;
        tree gnu_modulus;
        tree gnu_high = 0;

        if (Is_Packed_Array_Type (gnat_entity))
          esize = UI_To_Int (RM_Size (gnat_entity));

        /* Find the smallest mode at least ESIZE bits wide and make a class
           using that mode.  */

        for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT);
             GET_MODE_BITSIZE (mode) < esize;
             mode = GET_MODE_WIDER_MODE (mode))
          ;

        gnu_type = make_unsigned_type (GET_MODE_BITSIZE (mode));
        TYPE_PACKED_ARRAY_TYPE_P (gnu_type)
          = Is_Packed_Array_Type (gnat_entity);

        /* Get the modulus in this type.  If it overflows, assume it is because
           it is equal to 2**Esize.  Note that there is no overflow checking
           done on unsigned type, so we detect the overflow by looking for
           a modulus of zero, which is otherwise invalid.  */
        gnu_modulus = UI_To_gnu (Modulus (gnat_entity), gnu_type);

        if (!integer_zerop (gnu_modulus))
          {
            TYPE_MODULAR_P (gnu_type) = 1;
            SET_TYPE_MODULUS (gnu_type, gnu_modulus);
            gnu_high = fold_build2 (MINUS_EXPR, gnu_type, gnu_modulus,
                                    convert (gnu_type, integer_one_node));
          }

        /* If we have to set TYPE_PRECISION different from its natural value,
           make a subtype to do do.  Likewise if there is a modulus and
           it is not one greater than TYPE_MAX_VALUE.  */
        if (TYPE_PRECISION (gnu_type) != esize
            || (TYPE_MODULAR_P (gnu_type)
                && !tree_int_cst_equal (TYPE_MAX_VALUE (gnu_type), gnu_high)))
          {
            tree gnu_subtype = make_node (INTEGER_TYPE);

            TYPE_NAME (gnu_type) = create_concat_name (gnat_entity, "UMT");
            TREE_TYPE (gnu_subtype) = gnu_type;
            TYPE_MIN_VALUE (gnu_subtype) = TYPE_MIN_VALUE (gnu_type);
            TYPE_MAX_VALUE (gnu_subtype)
              = TYPE_MODULAR_P (gnu_type)
                ? gnu_high : TYPE_MAX_VALUE (gnu_type);
            TYPE_PRECISION (gnu_subtype) = esize;
            TYPE_UNSIGNED (gnu_subtype) = 1;
            TYPE_EXTRA_SUBTYPE_P (gnu_subtype) = 1;
            TYPE_PACKED_ARRAY_TYPE_P (gnu_subtype)
              = Is_Packed_Array_Type (gnat_entity);
            layout_type (gnu_subtype);

            gnu_type = gnu_subtype;
          }
      }
      break;

    case E_Signed_Integer_Subtype:
    case E_Enumeration_Subtype:
    case E_Modular_Integer_Subtype:
    case E_Ordinary_Fixed_Point_Subtype:
    case E_Decimal_Fixed_Point_Subtype:

      /* For integral subtypes, we make a new INTEGER_TYPE.  Note
         that we do not want to call build_range_type since we would
         like each subtype node to be distinct.  This will be important
         when memory aliasing is implemented.

         The TREE_TYPE field of the INTEGER_TYPE we make points to the
         parent type; this fact is used by the arithmetic conversion
         functions.

         We elaborate the Ancestor_Subtype if it is not in the current
         unit and one of our bounds is non-static.  We do this to ensure
         consistent naming in the case where several subtypes share the same
         bounds by always elaborating the first such subtype first, thus
         using its name. */

      if (!definition
          && Present (Ancestor_Subtype (gnat_entity))
          && !In_Extended_Main_Code_Unit (Ancestor_Subtype (gnat_entity))
          && (!Compile_Time_Known_Value (Type_Low_Bound (gnat_entity))
              || !Compile_Time_Known_Value (Type_High_Bound (gnat_entity))))
        gnat_to_gnu_entity (Ancestor_Subtype (gnat_entity),
                            gnu_expr, 0);

      gnu_type = make_node (INTEGER_TYPE);
      if (Is_Packed_Array_Type (gnat_entity))
        {
          esize = UI_To_Int (RM_Size (gnat_entity));
          TYPE_PACKED_ARRAY_TYPE_P (gnu_type) = 1;
        }

      TYPE_PRECISION (gnu_type) = esize;
      TREE_TYPE (gnu_type) = get_unpadded_type (Etype (gnat_entity));

      TYPE_MIN_VALUE (gnu_type)
        = convert (TREE_TYPE (gnu_type),
                   elaborate_expression (Type_Low_Bound (gnat_entity),
                                         gnat_entity,
                                         get_identifier ("L"), definition, 1,
                                         Needs_Debug_Info (gnat_entity)));

      TYPE_MAX_VALUE (gnu_type)
        = convert (TREE_TYPE (gnu_type),
                   elaborate_expression (Type_High_Bound (gnat_entity),
                                         gnat_entity,
                                         get_identifier ("U"), definition, 1,
                                         Needs_Debug_Info (gnat_entity)));

      /* One of the above calls might have caused us to be elaborated,
         so don't blow up if so.  */
      if (present_gnu_tree (gnat_entity))
        {
          maybe_present = true;
          break;
        }

      TYPE_BIASED_REPRESENTATION_P (gnu_type)
        = Has_Biased_Representation (gnat_entity);

     /* This should be an unsigned type if the lower bound is constant
         and non-negative or if the base type is unsigned; a signed type
         otherwise.    */
      TYPE_UNSIGNED (gnu_type)
        = (TYPE_UNSIGNED (TREE_TYPE (gnu_type))
           || (TREE_CODE (TYPE_MIN_VALUE (gnu_type)) == INTEGER_CST
               && TREE_INT_CST_HIGH (TYPE_MIN_VALUE (gnu_type)) >= 0)
           || TYPE_BIASED_REPRESENTATION_P (gnu_type)
           || Is_Unsigned_Type (gnat_entity));

      layout_type (gnu_type);

      /* Inherit our alias set from what we're a subtype of.  Subtypes
         are not different types and a pointer can designate any instance
         within a subtype hierarchy.  */
      copy_alias_set (gnu_type, TREE_TYPE (gnu_type));

      /* If the type we are dealing with is to represent a packed array,
         we need to have the bits left justified on big-endian targets
         and right justified on little-endian targets.  We also need to
         ensure that when the value is read (e.g. for comparison of two
         such values), we only get the good bits, since the unused bits
         are uninitialized.  Both goals are accomplished by wrapping the
         modular value in an enclosing struct.  */
        if (Is_Packed_Array_Type (gnat_entity))
        {
          tree gnu_field_type = gnu_type;
          tree gnu_field;

          TYPE_RM_SIZE_NUM (gnu_field_type)
            = UI_To_gnu (RM_Size (gnat_entity), bitsizetype);
          gnu_type = make_node (RECORD_TYPE);
          TYPE_NAME (gnu_type) = create_concat_name (gnat_entity, "JM");
          TYPE_ALIGN (gnu_type) = TYPE_ALIGN (gnu_field_type);
          TYPE_PACKED (gnu_type) = 1;

          /* Create a stripped-down declaration of the original type, mainly
             for debugging.  */
          create_type_decl (get_entity_name (gnat_entity), gnu_field_type,
                            NULL, true, debug_info_p, gnat_entity);

          /* Don't notify the field as "addressable", since we won't be taking
             it's address and it would prevent create_field_decl from making a
             bitfield.  */
          gnu_field = create_field_decl (get_identifier ("OBJECT"),
                                         gnu_field_type, gnu_type, 1, 0, 0, 0);

          finish_record_type (gnu_type, gnu_field, false, false);
          TYPE_JUSTIFIED_MODULAR_P (gnu_type) = 1;
          SET_TYPE_ADA_SIZE (gnu_type, bitsize_int (esize));

          copy_alias_set (gnu_type, gnu_field_type);
        }

      break;

    case E_Floating_Point_Type:
      /* If this is a VAX floating-point type, use an integer of the proper
         size.  All the operations will be handled with ASM statements.  */
      if (Vax_Float (gnat_entity))
        {
          gnu_type = make_signed_type (esize);
          TYPE_VAX_FLOATING_POINT_P (gnu_type) = 1;
          SET_TYPE_DIGITS_VALUE (gnu_type,
                                 UI_To_gnu (Digits_Value (gnat_entity),
                                            sizetype));
          break;
        }

      /* The type of the Low and High bounds can be our type if this is
         a type from Standard, so set them at the end of the function.  */
      gnu_type = make_node (REAL_TYPE);
      TYPE_PRECISION (gnu_type) = fp_size_to_prec (esize);
      layout_type (gnu_type);
      break;

    case E_Floating_Point_Subtype:
      if (Vax_Float (gnat_entity))
        {
          gnu_type = gnat_to_gnu_type (Etype (gnat_entity));
          break;
        }

      {
        if (!definition
            && Present (Ancestor_Subtype (gnat_entity))
            && !In_Extended_Main_Code_Unit (Ancestor_Subtype (gnat_entity))
            && (!Compile_Time_Known_Value (Type_Low_Bound (gnat_entity))
                || !Compile_Time_Known_Value (Type_High_Bound (gnat_entity))))
          gnat_to_gnu_entity (Ancestor_Subtype (gnat_entity),
                              gnu_expr, 0);

        gnu_type = make_node (REAL_TYPE);
        TREE_TYPE (gnu_type) = get_unpadded_type (Etype (gnat_entity));
        TYPE_PRECISION (gnu_type) = fp_size_to_prec (esize);

        TYPE_MIN_VALUE (gnu_type)
          = convert (TREE_TYPE (gnu_type),
                     elaborate_expression (Type_Low_Bound (gnat_entity),
                                           gnat_entity, get_identifier ("L"),
                                           definition, 1,
                                           Needs_Debug_Info (gnat_entity)));

        TYPE_MAX_VALUE (gnu_type)
          = convert (TREE_TYPE (gnu_type),
                     elaborate_expression (Type_High_Bound (gnat_entity),
                                           gnat_entity, get_identifier ("U"),
                                           definition, 1,
                                           Needs_Debug_Info (gnat_entity)));

        /* One of the above calls might have caused us to be elaborated,
           so don't blow up if so.  */
        if (present_gnu_tree (gnat_entity))
          {
            maybe_present = true;
            break;
          }

        layout_type (gnu_type);

        /* Inherit our alias set from what we're a subtype of, as for
           integer subtypes.  */
        copy_alias_set (gnu_type, TREE_TYPE (gnu_type));
      }
    break;

      /* Array and String Types and Subtypes

         Unconstrained array types are represented by E_Array_Type and
         constrained array types are represented by E_Array_Subtype.  There
         are no actual objects of an unconstrained array type; all we have
         are pointers to that type.

         The following fields are defined on array types and subtypes:

                Component_Type     Component type of the array.
                Number_Dimensions  Number of dimensions (an int).
                First_Index        Type of first index.  */

    case E_String_Type:
    case E_Array_Type:
      {
        tree gnu_template_fields = NULL_TREE;
        tree gnu_template_type = make_node (RECORD_TYPE);
        tree gnu_ptr_template = build_pointer_type (gnu_template_type);
        tree gnu_fat_type = make_node (RECORD_TYPE);
        int ndim = Number_Dimensions (gnat_entity);
        int firstdim
          = (Convention (gnat_entity) == Convention_Fortran) ? ndim - 1 : 0;
        int nextdim
          = (Convention (gnat_entity) == Convention_Fortran) ? - 1 : 1;
        tree *gnu_index_types = (tree *) alloca (ndim * sizeof (tree *));
        tree *gnu_temp_fields = (tree *) alloca (ndim * sizeof (tree *));
        tree gnu_comp_size = 0;
        tree gnu_max_size = size_one_node;
        tree gnu_max_size_unit;
        int index;
        Entity_Id gnat_ind_subtype;
        Entity_Id gnat_ind_base_subtype;
        tree gnu_template_reference;
        tree tem;

        TYPE_NAME (gnu_template_type)
          = create_concat_name (gnat_entity, "XUB");
        TYPE_NAME (gnu_fat_type) = create_concat_name (gnat_entity, "XUP");
        TYPE_IS_FAT_POINTER_P (gnu_fat_type) = 1;
        TYPE_READONLY (gnu_template_type) = 1;

        /* Make a node for the array.  If we are not defining the array
           suppress expanding incomplete types.  */
        gnu_type = make_node (UNCONSTRAINED_ARRAY_TYPE);

        if (!definition)
          defer_incomplete_level++, this_deferred = true;

        /* Build the fat pointer type.  Use a "void *" object instead of
           a pointer to the array type since we don't have the array type
           yet (it will reference the fat pointer via the bounds).  */
        tem = chainon (chainon (NULL_TREE,
                                create_field_decl (get_identifier ("P_ARRAY"),
                                                   ptr_void_type_node,
                                                   gnu_fat_type, 0, 0, 0, 0)),
                       create_field_decl (get_identifier ("P_BOUNDS"),
                                          gnu_ptr_template,
                                          gnu_fat_type, 0, 0, 0, 0));

        /* Make sure we can put this into a register.  */
        TYPE_ALIGN (gnu_fat_type) = MIN (BIGGEST_ALIGNMENT, 2 * POINTER_SIZE);
        finish_record_type (gnu_fat_type, tem, false, true);

        /* Build a reference to the template from a PLACEHOLDER_EXPR that
           is the fat pointer.  This will be used to access the individual
           fields once we build them.  */
        tem = build3 (COMPONENT_REF, gnu_ptr_template,
                      build0 (PLACEHOLDER_EXPR, gnu_fat_type),
                      TREE_CHAIN (TYPE_FIELDS (gnu_fat_type)), NULL_TREE);
        gnu_template_reference
          = build_unary_op (INDIRECT_REF, gnu_template_type, tem);
        TREE_READONLY (gnu_template_reference) = 1;

        /* Now create the GCC type for each index and add the fields for
           that index to the template.  */
        for (index = firstdim, gnat_ind_subtype = First_Index (gnat_entity),
             gnat_ind_base_subtype
               = First_Index (Implementation_Base_Type (gnat_entity));
             index < ndim && index >= 0;
             index += nextdim,
             gnat_ind_subtype = Next_Index (gnat_ind_subtype),
             gnat_ind_base_subtype = Next_Index (gnat_ind_base_subtype))
          {
            char field_name[10];
            tree gnu_ind_subtype
              = get_unpadded_type (Base_Type (Etype (gnat_ind_subtype)));
            tree gnu_base_subtype
              = get_unpadded_type (Etype (gnat_ind_base_subtype));
            tree gnu_base_min
              = convert (sizetype, TYPE_MIN_VALUE (gnu_base_subtype));
            tree gnu_base_max
              = convert (sizetype, TYPE_MAX_VALUE (gnu_base_subtype));
            tree gnu_min_field, gnu_max_field, gnu_min, gnu_max;

            /* Make the FIELD_DECLs for the minimum and maximum of this
               type and then make extractions of that field from the
               template.  */
            sprintf (field_name, "LB%d", index);
            gnu_min_field = create_field_decl (get_identifier (field_name),
                                               gnu_ind_subtype,
                                               gnu_template_type, 0, 0, 0, 0);
            field_name[0] = 'U';
            gnu_max_field = create_field_decl (get_identifier (field_name),
                                               gnu_ind_subtype,
                                               gnu_template_type, 0, 0, 0, 0);

            Sloc_to_locus (Sloc (gnat_entity),
                           &DECL_SOURCE_LOCATION (gnu_min_field));
            Sloc_to_locus (Sloc (gnat_entity),
                           &DECL_SOURCE_LOCATION (gnu_max_field));
            gnu_temp_fields[index] = chainon (gnu_min_field, gnu_max_field);

            /* We can't use build_component_ref here since the template
               type isn't complete yet.  */
            gnu_min = build3 (COMPONENT_REF, gnu_ind_subtype,
                              gnu_template_reference, gnu_min_field,
                              NULL_TREE);
            gnu_max = build3 (COMPONENT_REF, gnu_ind_subtype,
                              gnu_template_reference, gnu_max_field,
                              NULL_TREE);
            TREE_READONLY (gnu_min) = TREE_READONLY (gnu_max) = 1;

            /* Make a range type with the new ranges, but using
               the Ada subtype.  Then we convert to sizetype.  */
            gnu_index_types[index]
              = create_index_type (convert (sizetype, gnu_min),
                                   convert (sizetype, gnu_max),
                                   build_range_type (gnu_ind_subtype,
                                                     gnu_min, gnu_max));
            /* Update the maximum size of the array, in elements. */
            gnu_max_size
              = size_binop (MULT_EXPR, gnu_max_size,
                            size_binop (PLUS_EXPR, size_one_node,
                                        size_binop (MINUS_EXPR, gnu_base_max,
                                                    gnu_base_min)));

            TYPE_NAME (gnu_index_types[index])
              = create_concat_name (gnat_entity, field_name);
          }

        for (index = 0; index < ndim; index++)
          gnu_template_fields
            = chainon (gnu_template_fields, gnu_temp_fields[index]);

        /* Install all the fields into the template.  */
        finish_record_type (gnu_template_type, gnu_template_fields,
                            false, false);
        TYPE_READONLY (gnu_template_type) = 1;

        /* Now make the array of arrays and update the pointer to the array
           in the fat pointer.  Note that it is the first field.  */

        tem = gnat_to_gnu_type (Component_Type (gnat_entity));

        /* Get and validate any specified Component_Size, but if Packed,
           ignore it since the front end will have taken care of it. */
        gnu_comp_size
          = validate_size (Component_Size (gnat_entity), tem,
                           gnat_entity,
                           (Is_Bit_Packed_Array (gnat_entity)
                            ? TYPE_DECL : VAR_DECL),
                           true, Has_Component_Size_Clause (gnat_entity));

        if (Has_Atomic_Components (gnat_entity))
          check_ok_for_atomic (tem, gnat_entity, true);

        /* If the component type is a RECORD_TYPE that has a self-referential
           size, use the maxium size.  */
        if (!gnu_comp_size && TREE_CODE (tem) == RECORD_TYPE
            && CONTAINS_PLACEHOLDER_P (TYPE_SIZE (tem)))
          gnu_comp_size = max_size (TYPE_SIZE (tem), true);

        if (!Is_Bit_Packed_Array (gnat_entity) && gnu_comp_size)
          {
            tem = make_type_from_size (tem, gnu_comp_size, false);
            tem = maybe_pad_type (tem, gnu_comp_size, 0, gnat_entity,
                                  "C_PAD", false, definition, true);
          }

        if (Has_Volatile_Components (gnat_entity))
          tem = build_qualified_type (tem,
                                      TYPE_QUALS (tem) | TYPE_QUAL_VOLATILE);

        /* If Component_Size is not already specified, annotate it with the
           size of the component.  */
        if (Unknown_Component_Size (gnat_entity))
          Set_Component_Size (gnat_entity, annotate_value (TYPE_SIZE (tem)));

        gnu_max_size_unit = size_binop (MAX_EXPR, size_zero_node,
                                        size_binop (MULT_EXPR, gnu_max_size,
                                                    TYPE_SIZE_UNIT (tem)));
        gnu_max_size = size_binop (MAX_EXPR, bitsize_zero_node,
                                   size_binop (MULT_EXPR,
                                               convert (bitsizetype,
                                                        gnu_max_size),
                                               TYPE_SIZE (tem)));

        for (index = ndim - 1; index >= 0; index--)
          {
            tem = build_array_type (tem, gnu_index_types[index]);
            TYPE_MULTI_ARRAY_P (tem) = (index > 0);

            /* If the type below this is a multi-array type, then this
               does not have aliased components.  But we have to make
               them addressable if it must be passed by reference or
               if that is the default.  */
            if ((TREE_CODE (TREE_TYPE (tem)) == ARRAY_TYPE
                 && TYPE_MULTI_ARRAY_P (TREE_TYPE (tem)))
                || (!Has_Aliased_Components (gnat_entity)
                    && !must_pass_by_ref (TREE_TYPE (tem))
                    && !default_pass_by_ref (TREE_TYPE (tem))))
              TYPE_NONALIASED_COMPONENT (tem) = 1;
          }

        /* If an alignment is specified, use it if valid.  But ignore it for
           types that represent the unpacked base type for packed arrays.  */
        if (No (Packed_Array_Type (gnat_entity))
            && Known_Alignment (gnat_entity))
          {
            gcc_assert (Present (Alignment (gnat_entity)));
            TYPE_ALIGN (tem)
              = validate_alignment (Alignment (gnat_entity), gnat_entity,
                                    TYPE_ALIGN (tem));
          }

        TYPE_CONVENTION_FORTRAN_P (tem)
          = (Convention (gnat_entity) == Convention_Fortran);
        TREE_TYPE (TYPE_FIELDS (gnu_fat_type)) = build_pointer_type (tem);

        /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
           corresponding fat pointer.  */
        TREE_TYPE (gnu_type) = TYPE_POINTER_TO (gnu_type)
          = TYPE_REFERENCE_TO (gnu_type) = gnu_fat_type;
        TYPE_MODE (gnu_type) = BLKmode;
        TYPE_ALIGN (gnu_type) = TYPE_ALIGN (tem);
        SET_TYPE_UNCONSTRAINED_ARRAY (gnu_fat_type, gnu_type);

        /* If the maximum size doesn't overflow, use it.  */
        if (TREE_CODE (gnu_max_size) == INTEGER_CST
            && !TREE_OVERFLOW (gnu_max_size))
          TYPE_SIZE (tem)
            = size_binop (MIN_EXPR, gnu_max_size, TYPE_SIZE (tem));
        if (TREE_CODE (gnu_max_size_unit) == INTEGER_CST
            && !TREE_OVERFLOW (gnu_max_size_unit))
          TYPE_SIZE_UNIT (tem)
            = size_binop (MIN_EXPR, gnu_max_size_unit,
                          TYPE_SIZE_UNIT (tem));

        create_type_decl (create_concat_name (gnat_entity, "XUA"),
                          tem, NULL, !Comes_From_Source (gnat_entity),
                          debug_info_p, gnat_entity);

        /* Create a record type for the object and its template and
           set the template at a negative offset.  */
        tem = build_unc_object_type (gnu_template_type, tem,
                                     create_concat_name (gnat_entity, "XUT"));
        DECL_FIELD_OFFSET (TYPE_FIELDS (tem))
          = size_binop (MINUS_EXPR, size_zero_node,
                        byte_position (TREE_CHAIN (TYPE_FIELDS (tem))));
        DECL_FIELD_OFFSET (TREE_CHAIN (TYPE_FIELDS (tem))) = size_zero_node;
        DECL_FIELD_BIT_OFFSET (TREE_CHAIN (TYPE_FIELDS (tem)))
          = bitsize_zero_node;
        SET_TYPE_UNCONSTRAINED_ARRAY (tem, gnu_type);
        TYPE_OBJECT_RECORD_TYPE (gnu_type) = tem;

        /* Give the thin pointer type a name.  */
        create_type_decl (create_concat_name (gnat_entity, "XUX"),
                          build_pointer_type (tem), NULL,
                          !Comes_From_Source (gnat_entity), debug_info_p,
                          gnat_entity);
      }
      break;

    case E_String_Subtype:
    case E_Array_Subtype:

      /* This is the actual data type for array variables.  Multidimensional
         arrays are implemented in the gnu tree as arrays of arrays.  Note
         that for the moment arrays which have sparse enumeration subtypes as
         index components create sparse arrays, which is obviously space
         inefficient but so much easier to code for now.

         Also note that the subtype never refers to the unconstrained
         array type, which is somewhat at variance with Ada semantics.

         First check to see if this is simply a renaming of the array
         type.  If so, the result is the array type.  */

      gnu_type = gnat_to_gnu_type (Etype (gnat_entity));
      if (!Is_Constrained (gnat_entity))
        break;
      else
        {
          int index;
          int array_dim = Number_Dimensions (gnat_entity);
          int first_dim
            = ((Convention (gnat_entity) == Convention_Fortran)
               ? array_dim - 1 : 0);
          int next_dim
            = (Convention (gnat_entity) == Convention_Fortran) ? -1 : 1;
          Entity_Id gnat_ind_subtype;
          Entity_Id gnat_ind_base_subtype;
          tree gnu_base_type = gnu_type;
          tree *gnu_index_type = (tree *) alloca (array_dim * sizeof (tree *));
          tree gnu_comp_size = NULL_TREE;
          tree gnu_max_size = size_one_node;
          tree gnu_max_size_unit;
          bool need_index_type_struct = false;
          bool max_overflow = false;

          /* First create the gnu types for each index.  Create types for
             debugging information to point to the index types if the
             are not integer types, have variable bounds, or are
             wider than sizetype.  */

          for (index = first_dim, gnat_ind_subtype = First_Index (gnat_entity),
               gnat_ind_base_subtype
                 = First_Index (Implementation_Base_Type (gnat_entity));
               index < array_dim && index >= 0;
               index += next_dim,
               gnat_ind_subtype = Next_Index (gnat_ind_subtype),
               gnat_ind_base_subtype = Next_Index (gnat_ind_base_subtype))
            {
              tree gnu_index_subtype
                = get_unpadded_type (Etype (gnat_ind_subtype));
              tree gnu_min
                = convert (sizetype, TYPE_MIN_VALUE (gnu_index_subtype));
              tree gnu_max
                = convert (sizetype, TYPE_MAX_VALUE (gnu_index_subtype));
              tree gnu_base_subtype
                = get_unpadded_type (Etype (gnat_ind_base_subtype));
              tree gnu_base_min
                = convert (sizetype, TYPE_MIN_VALUE (gnu_base_subtype));
              tree gnu_base_max
                = convert (sizetype, TYPE_MAX_VALUE (gnu_base_subtype));
              tree gnu_base_type = get_base_type (gnu_base_subtype);
              tree gnu_base_base_min
                = convert (sizetype, TYPE_MIN_VALUE (gnu_base_type));
              tree gnu_base_base_max
                = convert (sizetype, TYPE_MAX_VALUE (gnu_base_type));
              tree gnu_high;
              tree gnu_this_max;

              /* If the minimum and maximum values both overflow in
                 SIZETYPE, but the difference in the original type
                 does not overflow in SIZETYPE, ignore the overflow
                 indications.  */
              if ((TYPE_PRECISION (gnu_index_subtype)
                   > TYPE_PRECISION (sizetype)
                   || TYPE_UNSIGNED (gnu_index_subtype)
                      != TYPE_UNSIGNED (sizetype))
                  && TREE_CODE (gnu_min) == INTEGER_CST
                  && TREE_CODE (gnu_max) == INTEGER_CST
                  && TREE_OVERFLOW (gnu_min) && TREE_OVERFLOW (gnu_max)
                  && (!TREE_OVERFLOW
                      (fold_build2 (MINUS_EXPR, gnu_index_subtype,
                                    TYPE_MAX_VALUE (gnu_index_subtype),
                                    TYPE_MIN_VALUE (gnu_index_subtype)))))
                {
                  TREE_OVERFLOW (gnu_min) = 0;
                  TREE_OVERFLOW (gnu_max) = 0;
                }

              /* Similarly, if the range is null, use bounds of 1..0 for
                 the sizetype bounds.  */
              else if ((TYPE_PRECISION (gnu_index_subtype)
                        > TYPE_PRECISION (sizetype)
                       || TYPE_UNSIGNED (gnu_index_subtype)
                          != TYPE_UNSIGNED (sizetype))
                       && TREE_CODE (gnu_min) == INTEGER_CST
                       && TREE_CODE (gnu_max) == INTEGER_CST
                       && (TREE_OVERFLOW (gnu_min) || TREE_OVERFLOW (gnu_max))
                       && tree_int_cst_lt (TYPE_MAX_VALUE (gnu_index_subtype),
                                           TYPE_MIN_VALUE (gnu_index_subtype)))
                gnu_min = size_one_node, gnu_max = size_zero_node;

              /* Now compute the size of this bound.  We need to provide
                 GCC with an upper bound to use but have to deal with the
                 "superflat" case.  There are three ways to do this.  If we
                 can prove that the array can never be superflat, we can
                 just use the high bound of the index subtype.  If we can
                 prove that the low bound minus one can't overflow, we
                 can do this as MAX (hb, lb - 1).  Otherwise, we have to use
                 the expression hb >= lb ? hb : lb - 1.  */
              gnu_high = size_binop (MINUS_EXPR, gnu_min, size_one_node);

              /* See if the base array type is already flat.  If it is, we
                 are probably compiling an ACVC test, but it will cause the
                 code below to malfunction if we don't handle it specially.  */
              if (TREE_CODE (gnu_base_min) == INTEGER_CST
                  && TREE_CODE (gnu_base_max) == INTEGER_CST
                  && !TREE_OVERFLOW (gnu_base_min)
                  && !TREE_OVERFLOW (gnu_base_max)
                  && tree_int_cst_lt (gnu_base_max, gnu_base_min))
                gnu_high = size_zero_node, gnu_min = size_one_node;

              /* If gnu_high is now an integer which overflowed, the array
                 cannot be superflat.  */
              else if (TREE_CODE (gnu_high) == INTEGER_CST
                       && TREE_OVERFLOW (gnu_high))
                gnu_high = gnu_max;
              else if (TYPE_UNSIGNED (gnu_base_subtype)
                       || TREE_CODE (gnu_high) == INTEGER_CST)
                gnu_high = size_binop (MAX_EXPR, gnu_max, gnu_high);
              else
                gnu_high
                  = build_cond_expr
                    (sizetype, build_binary_op (GE_EXPR, integer_type_node,
                                                gnu_max, gnu_min),
                     gnu_max, gnu_high);

              gnu_index_type[index]
                = create_index_type (gnu_min, gnu_high, gnu_index_subtype);

              /* Also compute the maximum size of the array.  Here we
                 see if any constraint on the index type of the base type
                 can be used in the case of self-referential bound on
                 the index type of the subtype.  We look for a non-"infinite"
                 and non-self-referential bound from any type involved and
                 handle each bound separately.  */

              if ((TREE_CODE (gnu_min) == INTEGER_CST
                   && !TREE_OVERFLOW (gnu_min)
                   && !operand_equal_p (gnu_min, gnu_base_base_min, 0))
                  || !CONTAINS_PLACEHOLDER_P (gnu_min)
                  || !(TREE_CODE (gnu_base_min) == INTEGER_CST
                       && !TREE_OVERFLOW (gnu_base_min)))
                gnu_base_min = gnu_min;

              if ((TREE_CODE (gnu_max) == INTEGER_CST
                   && !TREE_OVERFLOW (gnu_max)
                   && !operand_equal_p (gnu_max, gnu_base_base_max, 0))
                  || !CONTAINS_PLACEHOLDER_P (gnu_max)
                  || !(TREE_CODE (gnu_base_max) == INTEGER_CST
                       && !TREE_OVERFLOW (gnu_base_max)))
                gnu_base_max = gnu_max;

              if ((TREE_CODE (gnu_base_min) == INTEGER_CST
                   && TREE_OVERFLOW (gnu_base_min))
                  || operand_equal_p (gnu_base_min, gnu_base_base_min, 0)
                  || (TREE_CODE (gnu_base_max) == INTEGER_CST
                      && TREE_OVERFLOW (gnu_base_max))
                  || operand_equal_p (gnu_base_max, gnu_base_base_max, 0))
                max_overflow = true;

              gnu_base_min = size_binop (MAX_EXPR, gnu_base_min, gnu_min);
              gnu_base_max = size_binop (MIN_EXPR, gnu_base_max, gnu_max);

              gnu_this_max
                = size_binop (MAX_EXPR,
                              size_binop (PLUS_EXPR, size_one_node,
                                          size_binop (MINUS_EXPR, gnu_base_max,
                                                      gnu_base_min)),
                              size_zero_node);

              if (TREE_CODE (gnu_this_max) == INTEGER_CST
                  && TREE_OVERFLOW (gnu_this_max))
                max_overflow = true;

              gnu_max_size
                = size_binop (MULT_EXPR, gnu_max_size, gnu_this_max);

              if (!integer_onep (TYPE_MIN_VALUE (gnu_index_subtype))
                  || (TREE_CODE (TYPE_MAX_VALUE (gnu_index_subtype))
                      != INTEGER_CST)
                  || TREE_CODE (gnu_index_subtype) != INTEGER_TYPE
                  || (TREE_TYPE (gnu_index_subtype)
                      && (TREE_CODE (TREE_TYPE (gnu_index_subtype))
                          != INTEGER_TYPE))
                  || TYPE_BIASED_REPRESENTATION_P (gnu_index_subtype)
                  || (TYPE_PRECISION (gnu_index_subtype)
                      > TYPE_PRECISION (sizetype)))
                need_index_type_struct = true;
            }

          /* Then flatten: create the array of arrays.  */

          gnu_type = gnat_to_gnu_type (Component_Type (gnat_entity));

          /* One of the above calls might have caused us to be elaborated,
             so don't blow up if so.  */
          if (present_gnu_tree (gnat_entity))
            {
              maybe_present = true;
              break;
            }

          /* Get and validate any specified Component_Size, but if Packed,
             ignore it since the front end will have taken care of it. */
          gnu_comp_size
            = validate_size (Component_Size (gnat_entity), gnu_type,
                             gnat_entity,
                             (Is_Bit_Packed_Array (gnat_entity)
                              ? TYPE_DECL : VAR_DECL),
                             true, Has_Component_Size_Clause (gnat_entity));

          /* If the component type is a RECORD_TYPE that has a self-referential
             size, use the maxium size.  */
          if (!gnu_comp_size && TREE_CODE (gnu_type) == RECORD_TYPE
              && CONTAINS_PLACEHOLDER_P (TYPE_SIZE (gnu_type)))
            gnu_comp_size = max_size (TYPE_SIZE (gnu_type), true);

          if (!Is_Bit_Packed_Array (gnat_entity) && gnu_comp_size)
            {
              gnu_type = make_type_from_size (gnu_type, gnu_comp_size, false);
              gnu_type = maybe_pad_type (gnu_type, gnu_comp_size, 0,
                                         gnat_entity, "C_PAD", false,
                                         definition, true);
            }

          if (Has_Volatile_Components (Base_Type (gnat_entity)))
            gnu_type = build_qualified_type (gnu_type,
                                             (TYPE_QUALS (gnu_type)
                                              | TYPE_QUAL_VOLATILE));

          gnu_max_size_unit = size_binop (MULT_EXPR, gnu_max_size,
                                          TYPE_SIZE_UNIT (gnu_type));
          gnu_max_size = size_binop (MULT_EXPR,
                                     convert (bitsizetype, gnu_max_size),
                                     TYPE_SIZE (gnu_type));

          for (index = array_dim - 1; index >= 0; index --)
            {
              gnu_type = build_array_type (gnu_type, gnu_index_type[index]);
              TYPE_MULTI_ARRAY_P (gnu_type) = (index > 0);

              /* If the type below this is a multi-array type, then this
                 does not have aliased components.  But we have to make
                 them addressable if it must be passed by reference or
                 if that is the default.  */
              if ((TREE_CODE (TREE_TYPE (gnu_type)) == ARRAY_TYPE
                   && TYPE_MULTI_ARRAY_P (TREE_TYPE (gnu_type)))
                  || (!Has_Aliased_Components (gnat_entity)
                      && !must_pass_by_ref (TREE_TYPE (gnu_type))
                      && !default_pass_by_ref (TREE_TYPE (gnu_type))))
                TYPE_NONALIASED_COMPONENT (gnu_type) = 1;
            }

          /* If we are at file level and this is a multi-dimensional array, we
             need to make a variable corresponding to the stride of the
             inner dimensions.   */
          if (global_bindings_p () && array_dim > 1)
            {
              tree gnu_str_name = get_identifier ("ST");
              tree gnu_arr_type;

              for (gnu_arr_type = TREE_TYPE (gnu_type);
                   TREE_CODE (gnu_arr_type) == ARRAY_TYPE;
                   gnu_arr_type = TREE_TYPE (gnu_arr_type),
                   gnu_str_name = concat_id_with_name (gnu_str_name, "ST"))
                {
                  tree eltype = TREE_TYPE (gnu_arr_type);

                  TYPE_SIZE (gnu_arr_type)
                    = elaborate_expression_1 (gnat_entity, gnat_entity,
                                              TYPE_SIZE (gnu_arr_type),
                                              gnu_str_name, definition, 0);

                  /* ??? For now, store the size as a multiple of the
                     alignment of the element type in bytes so that we
                     can see the alignment from the tree.  */
                  TYPE_SIZE_UNIT (gnu_arr_type)
                    = build_binary_op
                      (MULT_EXPR, sizetype,
                       elaborate_expression_1
                       (gnat_entity, gnat_entity,
                        build_binary_op (EXACT_DIV_EXPR, sizetype,
                                         TYPE_SIZE_UNIT (gnu_arr_type),
                                         size_int (TYPE_ALIGN (eltype)
                                                   / BITS_PER_UNIT)),
                        concat_id_with_name (gnu_str_name, "A_U"),
                        definition, 0),
                       size_int (TYPE_ALIGN (eltype) / BITS_PER_UNIT));
                }
            }

          /* If we need to write out a record type giving the names of
             the bounds, do it now.  */
          if (need_index_type_struct && debug_info_p)
            {
              tree gnu_bound_rec_type = make_node (RECORD_TYPE);
              tree gnu_field_list = NULL_TREE;
              tree gnu_field;

              TYPE_NAME (gnu_bound_rec_type)
                = create_concat_name (gnat_entity, "XA");

              for (index = array_dim - 1; index >= 0; index--)
                {
                  tree gnu_type_name
                    = TYPE_NAME (TYPE_INDEX_TYPE (gnu_index_type[index]));

                  if (TREE_CODE (gnu_type_name) == TYPE_DECL)
                    gnu_type_name = DECL_NAME (gnu_type_name);

                  gnu_field = create_field_decl (gnu_type_name,
                                                 integer_type_node,
                                                 gnu_bound_rec_type,
                                                 0, NULL_TREE, NULL_TREE, 0);
                  TREE_CHAIN (gnu_field) = gnu_field_list;
                  gnu_field_list = gnu_field;
                }

              finish_record_type (gnu_bound_rec_type, gnu_field_list,
                                  false, false);
            }

          TYPE_CONVENTION_FORTRAN_P (gnu_type)
            = (Convention (gnat_entity) == Convention_Fortran);
          TYPE_PACKED_ARRAY_TYPE_P (gnu_type)
            = Is_Packed_Array_Type (gnat_entity);

          /* If our size depends on a placeholder and the maximum size doesn't
             overflow, use it.  */
          if (CONTAINS_PLACEHOLDER_P (TYPE_SIZE (gnu_type))
              && !(TREE_CODE (gnu_max_size) == INTEGER_CST
                   && TREE_OVERFLOW (gnu_max_size))
              && !(TREE_CODE (gnu_max_size_unit) == INTEGER_CST
                   && TREE_OVERFLOW (gnu_max_size_unit))
              && !max_overflow)
            {
              TYPE_SIZE (gnu_type) = size_binop (MIN_EXPR, gnu_max_size,
                                                 TYPE_SIZE (gnu_type));
              TYPE_SIZE_UNIT (gnu_type)
                = size_binop (MIN_EXPR, gnu_max_size_unit,
                              TYPE_SIZE_UNIT (gnu_type));
            }

          /* Set our alias set to that of our base type.  This gives all
             array subtypes the same alias set.  */
          copy_alias_set (gnu_type, gnu_base_type);
        }

      /* If this is a packed type, make this type the same as the packed
         array type, but do some adjusting in the type first.   */

      if (Present (Packed_Array_Type (gnat_entity)))
        {
          Entity_Id gnat_index;
          tree gnu_inner_type;

          /* First finish the type we had been making so that we output
             debugging information for it  */
          gnu_type
            = build_qualified_type (gnu_type,
                                    (TYPE_QUALS (gnu_type)
                                     | (TYPE_QUAL_VOLATILE
                                        * Treat_As_Volatile (gnat_entity))));
          gnu_decl = create_type_decl (gnu_entity_id, gnu_type, attr_list,
                                       !Comes_From_Source (gnat_entity),
                                       debug_info_p, gnat_entity);
          if (!Comes_From_Source (gnat_entity))
            DECL_ARTIFICIAL (gnu_decl) = 1;

          /* Save it as our equivalent in case the call below elaborates
             this type again.  */
          save_gnu_tree (gnat_entity, gnu_decl, false);

          gnu_decl = gnat_to_gnu_entity (Packed_Array_Type (gnat_entity),
                                         NULL_TREE, 0);
          this_made_decl = true;
          gnu_inner_type = gnu_type = TREE_TYPE (gnu_decl);
          save_gnu_tree (gnat_entity, NULL_TREE, false);

          while (TREE_CODE (gnu_inner_type) == RECORD_TYPE
                 && (TYPE_JUSTIFIED_MODULAR_P (gnu_inner_type)
                     || TYPE_IS_PADDING_P (gnu_inner_type)))
            gnu_inner_type = TREE_TYPE (TYPE_FIELDS (gnu_inner_type));

          /* We need to point the type we just made to our index type so
             the actual bounds can be put into a template.  */

          if ((TREE_CODE (gnu_inner_type) == ARRAY_TYPE
               && !TYPE_ACTUAL_BOUNDS (gnu_inner_type))
              || (TREE_CODE (gnu_inner_type) == INTEGER_TYPE
                  && !TYPE_HAS_ACTUAL_BOUNDS_P (gnu_inner_type)))
            {
              if (TREE_CODE (gnu_inner_type) == INTEGER_TYPE)
                {
                  /* The TYPE_ACTUAL_BOUNDS field is also used for the modulus.
                     If it is, we need to make another type.  */
                  if (TYPE_MODULAR_P (gnu_inner_type))
                    {
                      tree gnu_subtype;

                      gnu_subtype = make_node (INTEGER_TYPE);

                      TREE_TYPE (gnu_subtype) = gnu_inner_type;
                      TYPE_MIN_VALUE (gnu_subtype)
                        = TYPE_MIN_VALUE (gnu_inner_type);
                      TYPE_MAX_VALUE (gnu_subtype)
                        = TYPE_MAX_VALUE (gnu_inner_type);
                      TYPE_PRECISION (gnu_subtype)
                        = TYPE_PRECISION (gnu_inner_type);
                      TYPE_UNSIGNED (gnu_subtype)
                        = TYPE_UNSIGNED (gnu_inner_type);
                      TYPE_EXTRA_SUBTYPE_P (gnu_subtype) = 1;
                      layout_type (gnu_subtype);

                      gnu_inner_type = gnu_subtype;
                    }

                  TYPE_HAS_ACTUAL_BOUNDS_P (gnu_inner_type) = 1;
                }

              SET_TYPE_ACTUAL_BOUNDS (gnu_inner_type, NULL_TREE);

              for (gnat_index = First_Index (gnat_entity);
                   Present (gnat_index); gnat_index = Next_Index (gnat_index))
                SET_TYPE_ACTUAL_BOUNDS
                  (gnu_inner_type,
                   tree_cons (NULL_TREE,
                              get_unpadded_type (Etype (gnat_index)),
                              TYPE_ACTUAL_BOUNDS (gnu_inner_type)));

              if (Convention (gnat_entity) != Convention_Fortran)
                SET_TYPE_ACTUAL_BOUNDS
                  (gnu_inner_type,
                   nreverse (TYPE_ACTUAL_BOUNDS (gnu_inner_type)));

              if (TREE_CODE (gnu_type) == RECORD_TYPE
                  && TYPE_JUSTIFIED_MODULAR_P (gnu_type))
                TREE_TYPE (TYPE_FIELDS (gnu_type)) = gnu_inner_type;
            }
        }

      /* Abort if packed array with no packed array type field set. */
      else
        gcc_assert (!Is_Packed (gnat_entity));

      break;

    case E_String_Literal_Subtype:
      /* Create the type for a string literal. */
      {
        Entity_Id gnat_full_type
          = (IN (Ekind (Etype (gnat_entity)), Private_Kind)
             && Present (Full_View (Etype (gnat_entity)))
             ? Full_View (Etype (gnat_entity)) : Etype (gnat_entity));
        tree gnu_string_type = get_unpadded_type (gnat_full_type);
        tree gnu_string_array_type
          = TREE_TYPE (TREE_TYPE (TYPE_FIELDS (TREE_TYPE (gnu_string_type))));
        tree gnu_string_index_type
          = get_base_type (TREE_TYPE (TYPE_INDEX_TYPE
                                      (TYPE_DOMAIN (gnu_string_array_type))));
        tree gnu_lower_bound
          = convert (gnu_string_index_type,
                     gnat_to_gnu (String_Literal_Low_Bound (gnat_entity)));
        int length = UI_To_Int (String_Literal_Length (gnat_entity));
        tree gnu_length = ssize_int (length - 1);
        tree gnu_upper_bound
          = build_binary_op (PLUS_EXPR, gnu_string_index_type,
                             gnu_lower_bound,
                             convert (gnu_string_index_type, gnu_length));
        tree gnu_range_type
          = build_range_type (gnu_string_index_type,
                              gnu_lower_bound, gnu_upper_bound);
        tree gnu_index_type
          = create_index_type (convert (sizetype,
                                        TYPE_MIN_VALUE (gnu_range_type)),
                               convert (sizetype,
                                        TYPE_MAX_VALUE (gnu_range_type)),
                               gnu_range_type);

        gnu_type
          = build_array_type (gnat_to_gnu_type (Component_Type (gnat_entity)),
                              gnu_index_type);
        copy_alias_set (gnu_type,  gnu_string_type);
      }
      break;

    /* Record Types and Subtypes

       The following fields are defined on record types:

                Has_Discriminants       True if the record has discriminants
                First_Discriminant      Points to head of list of discriminants
                First_Entity            Points to head of list of fields
                Is_Tagged_Type          True if the record is tagged

       Implementation of Ada records and discriminated records:

       A record type definition is transformed into the equivalent of a C
       struct definition.  The fields that are the discriminants which are
       found in the Full_Type_Declaration node and the elements of the
       Component_List found in the Record_Type_Definition node.  The
       Component_List can be a recursive structure since each Variant of
       the Variant_Part of the Component_List has a Component_List.

       Processing of a record type definition comprises starting the list of
       field declarations here from the discriminants and the calling the
       function components_to_record to add the rest of the fields from the
       component list and return the gnu type node. The function
       components_to_record will call itself recursively as it traverses
       the tree.  */

    case E_Record_Type:
      if (Has_Complex_Representation (gnat_entity))
        {
          gnu_type
            = build_complex_type
              (get_unpadded_type
               (Etype (Defining_Entity
                       (First (Component_Items
                               (Component_List
                                (Type_Definition
                                 (Declaration_Node (gnat_entity)))))))));

          break;
        }

      {
        Node_Id full_definition = Declaration_Node (gnat_entity);
        Node_Id record_definition = Type_Definition (full_definition);
        Entity_Id gnat_field;
        tree gnu_field;
        tree gnu_field_list = NULL_TREE;
        tree gnu_get_parent;
        int packed = (Is_Packed (gnat_entity) ? 1
                      : (Component_Alignment (gnat_entity)
                         == Calign_Storage_Unit) ? -1
                      : 0);
        bool has_rep = Has_Specified_Layout (gnat_entity);
        bool all_rep = has_rep;
        bool is_extension
          = (Is_Tagged_Type (gnat_entity)
             && Nkind (record_definition) == N_Derived_Type_Definition);

        /* See if all fields have a rep clause.  Stop when we find one
           that doesn't.  */
        for (gnat_field = First_Entity (gnat_entity);
             Present (gnat_field) && all_rep;
             gnat_field = Next_Entity (gnat_field))
          if ((Ekind (gnat_field) == E_Component
               || Ekind (gnat_field) == E_Discriminant)
              && No (Component_Clause (gnat_field)))
            all_rep = false;

        /* If this is a record extension, go a level further to find the
           record definition.  Also, verify we have a Parent_Subtype.  */
        if (is_extension)
          {
            if (!type_annotate_only
                || Present (Record_Extension_Part (record_definition)))
              record_definition = Record_Extension_Part (record_definition);

            gcc_assert (type_annotate_only
                        || Present (Parent_Subtype (gnat_entity)));
          }

        /* Make a node for the record.  If we are not defining the record,
           suppress expanding incomplete types.  */
        gnu_type = make_node (tree_code_for_record_type (gnat_entity));
        TYPE_NAME (gnu_type) = gnu_entity_id;
        /* ??? We should have create_type_decl like in the E_Record_Subtype
           case below.  Unfortunately this would cause GNU_TYPE to be marked
           as visited, thus precluding the subtrees of the type that will be
           built below from being marked as visited when the real TYPE_DECL
           is eventually created.  A solution could be to devise a special
           version of the function under the name create_type_stub_decl.  */
        TYPE_STUB_DECL (gnu_type)
          = build_decl (TYPE_DECL, NULL_TREE, gnu_type);
        TYPE_ALIGN (gnu_type) = 0;
        TYPE_PACKED (gnu_type) = packed || has_rep;

        if (!definition)
          defer_incomplete_level++, this_deferred = true;

        /* If both a size and rep clause was specified, put the size in
           the record type now so that it can get the proper mode.  */
        if (has_rep && Known_Esize (gnat_entity))
          TYPE_SIZE (gnu_type) = UI_To_gnu (Esize (gnat_entity), sizetype);

        /* Always set the alignment here so that it can be used to
           set the mode, if it is making the alignment stricter.  If
           it is invalid, it will be checked again below.  If this is to
           be Atomic, choose a default alignment of a word unless we know
           the size and it's smaller.  */
        if (Known_Alignment (gnat_entity))
          TYPE_ALIGN (gnu_type)
            = validate_alignment (Alignment (gnat_entity), gnat_entity, 0);
        else if (Is_Atomic (gnat_entity))
          TYPE_ALIGN (gnu_type)
            = (esize >= BITS_PER_WORD ? BITS_PER_WORD
               : 1 << (floor_log2 (esize - 1) + 1));

        /* If we have a Parent_Subtype, make a field for the parent.  If
           this record has rep clauses, force the position to zero.  */
        if (Present (Parent_Subtype (gnat_entity)))
          {
            Entity_Id gnat_parent = Parent_Subtype (gnat_entity);
            tree gnu_parent;

            /* A major complexity here is that the parent subtype will
               reference our discriminants in its Discriminant_Constraint
               list.  But those must reference the parent component of this
               record which is of the parent subtype we have not built yet!
               To break the circle we first build a dummy COMPONENT_REF which
               represents the "get to the parent" operation and initialize
               each of those discriminants to a COMPONENT_REF of the above
               dummy parent referencing the corresponding discriminant of the
               base type of the parent subtype.  */
            gnu_get_parent = build3 (COMPONENT_REF, void_type_node,
                                     build0 (PLACEHOLDER_EXPR, gnu_type),
                                     build_decl (FIELD_DECL, NULL_TREE,
                                                 NULL_TREE),
                                     NULL_TREE);

            if (Has_Discriminants (gnat_entity))
              for (gnat_field = First_Stored_Discriminant (gnat_entity);
                   Present (gnat_field);
                   gnat_field = Next_Stored_Discriminant (gnat_field))
                if (Present (Corresponding_Discriminant (gnat_field)))
                  save_gnu_tree
                    (gnat_field,
                     build3 (COMPONENT_REF,
                             get_unpadded_type (Etype (gnat_field)),
                             gnu_get_parent,
                             gnat_to_gnu_field_decl (Corresponding_Discriminant
                                                     (gnat_field)),
                             NULL_TREE),
                     true);

            /* Then we build the parent subtype.  */
            gnu_parent = gnat_to_gnu_type (gnat_parent);

            /* Finally we fix up both kinds of twisted COMPONENT_REF we have
               initially built.  The discriminants must reference the fields
               of the parent subtype and not those of its base type for the
               placeholder machinery to properly work.  */
            if (Has_Discriminants (gnat_entity))
              for (gnat_field = First_Stored_Discriminant (gnat_entity);
                   Present (gnat_field);
                   gnat_field = Next_Stored_Discriminant (gnat_field))
                if (Present (Corresponding_Discriminant (gnat_field)))
                  {
                    Entity_Id field = Empty;
                    for (field = First_Stored_Discriminant (gnat_parent);
                         Present (field);
                         field = Next_Stored_Discriminant (field))
                      if (same_discriminant_p (gnat_field, field))
                        break;
                    gcc_assert (Present (field));
                    TREE_OPERAND (get_gnu_tree (gnat_field), 1)
                      = gnat_to_gnu_field_decl (field);
                  }

            /* The "get to the parent" COMPONENT_REF must be given its
               proper type...  */
            TREE_TYPE (gnu_get_parent) = gnu_parent;

            /* ...and reference the _parent field of this record.  */
            gnu_field_list
              = create_field_decl (get_identifier
                                   (Get_Name_String (Name_uParent)),
                                   gnu_parent, gnu_type, 0,
                                   has_rep ? TYPE_SIZE (gnu_parent) : 0,
                                   has_rep ? bitsize_zero_node : 0, 1);
            DECL_INTERNAL_P (gnu_field_list) = 1;
            TREE_OPERAND (gnu_get_parent, 1) = gnu_field_list;
          }

        /* Make the fields for the discriminants and put them into the record
           unless it's an Unchecked_Union.  */
        if (Has_Discriminants (gnat_entity))
          for (gnat_field = First_Stored_Discriminant (gnat_entity);
               Present (gnat_field);
               gnat_field = Next_Stored_Discriminant (gnat_field))
            {
              /* If this is a record extension and this discriminant
                 is the renaming of another discriminant, we've already
                 handled the discriminant above.  */
              if (Present (Parent_Subtype (gnat_entity))
                  && Present (Corresponding_Discriminant (gnat_field)))
                continue;

              gnu_field
                = gnat_to_gnu_field (gnat_field, gnu_type, packed, definition);

              /* Make an expression using a PLACEHOLDER_EXPR from the
                 FIELD_DECL node just created and link that with the
                 corresponding GNAT defining identifier.  Then add to the
                 list of fields.  */
              save_gnu_tree (gnat_field,
                             build3 (COMPONENT_REF, TREE_TYPE (gnu_field),
                                     build0 (PLACEHOLDER_EXPR,
                                             DECL_CONTEXT (gnu_field)),
                                     gnu_field, NULL_TREE),
                             true);

              if (!Is_Unchecked_Union (gnat_entity))
                {
                  TREE_CHAIN (gnu_field) = gnu_field_list;
                  gnu_field_list = gnu_field;
                }
            }

        /* Put the discriminants into the record (backwards), so we can
           know the appropriate discriminant to use for the names of the
           variants.  */
        TYPE_FIELDS (gnu_type) = gnu_field_list;

        /* Add the listed fields into the record and finish up.  */
        components_to_record (gnu_type, Component_List (record_definition),
                              gnu_field_list, packed, definition, NULL,
                              false, all_rep, this_deferred,
                              Is_Unchecked_Union (gnat_entity));

        if (this_deferred)
          {
            debug_deferred = true;
            defer_debug_level++;

            defer_debug_incomplete_list
              = tree_cons (NULL_TREE, gnu_type,
                           defer_debug_incomplete_list);
          }

        /* We used to remove the associations of the discriminants and
           _Parent for validity checking, but we may need them if there's
           Freeze_Node for a subtype used in this record.  */

        TYPE_VOLATILE (gnu_type) = Treat_As_Volatile (gnat_entity);
        TYPE_BY_REFERENCE_P (gnu_type) = Is_By_Reference_Type (gnat_entity);

        /* If it is a tagged record force the type to BLKmode to insure
           that these objects will always be placed in memory. Do the
           same thing for limited record types. */
        if (Is_Tagged_Type (gnat_entity) || Is_Limited_Record (gnat_entity))
          TYPE_MODE (gnu_type) = BLKmode;

        /* If this is a derived type, we must make the alias set of this type
           the same as that of the type we are derived from.  We assume here
           that the other type is already frozen. */
        if (Etype (gnat_entity) != gnat_entity
            && !(Is_Private_Type (Etype (gnat_entity))
                 && Full_View (Etype (gnat_entity)) == gnat_entity))
          copy_alias_set (gnu_type, gnat_to_gnu_type (Etype (gnat_entity)));

        /* Fill in locations of fields.  */
        annotate_rep (gnat_entity, gnu_type);

        /* If there are any entities in the chain corresponding to
           components that we did not elaborate, ensure we elaborate their
           types if they are Itypes.  */
        for (gnat_temp = First_Entity (gnat_entity);
             Present (gnat_temp); gnat_temp = Next_Entity (gnat_temp))
          if ((Ekind (gnat_temp) == E_Component
               || Ekind (gnat_temp) == E_Discriminant)
              && Is_Itype (Etype (gnat_temp))
              && !present_gnu_tree (gnat_temp))
            gnat_to_gnu_entity (Etype (gnat_temp), NULL_TREE, 0);
      }
      break;

    case E_Class_Wide_Subtype:
      /* If an equivalent type is present, that is what we should use.
         Otherwise, fall through to handle this like a record subtype
         since it may have constraints.  */
      if (Present (Equivalent_Type (gnat_entity)))
        {
          gnu_decl = gnat_to_gnu_entity (Equivalent_Type (gnat_entity),
                                         NULL_TREE, 0);
          maybe_present = true;
          break;
        }

      /* ... fall through ... */

    case E_Record_Subtype:

      /* If Cloned_Subtype is Present it means this record subtype has
         identical layout to that type or subtype and we should use
         that GCC type for this one.  The front end guarantees that
         the component list is shared.  */
      if (Present (Cloned_Subtype (gnat_entity)))
        {
          gnu_decl = gnat_to_gnu_entity (Cloned_Subtype (gnat_entity),
                                         NULL_TREE, 0);
          maybe_present = true;
        }

      /* Otherwise, first ensure the base type is elaborated.  Then, if we are
         changing the type, make a new type with each field having the
         type of the field in the new subtype but having the position
         computed by transforming every discriminant reference according
         to the constraints.  We don't see any difference between
         private and nonprivate type here since derivations from types should
         have been deferred until the completion of the private type.  */
      else
        {
          Entity_Id gnat_base_type = Implementation_Base_Type (gnat_entity);
          tree gnu_base_type;
          tree gnu_orig_type;

          if (!definition)
            defer_incomplete_level++, this_deferred = true;

          /* Get the base type initially for its alignment and sizes.  But
             if it is a padded type, we do all the other work with the
             unpadded type.  */
          gnu_type = gnu_orig_type = gnu_base_type
            = gnat_to_gnu_type (gnat_base_type);

          if (TREE_CODE (gnu_type) == RECORD_TYPE
              && TYPE_IS_PADDING_P (gnu_type))
            gnu_type = gnu_orig_type = TREE_TYPE (TYPE_FIELDS (gnu_type));

          if (present_gnu_tree (gnat_entity))
            {
              maybe_present = true;
              break;
            }

          /* When the type has discriminants, and these discriminants
             affect the shape of what it built, factor them in.

             If we are making a subtype of an Unchecked_Union (must be an
             Itype), just return the type.

             We can't just use Is_Constrained because private subtypes without
             discriminants of full types with discriminants with default
             expressions are Is_Constrained but aren't constrained!  */

          if (IN (Ekind (gnat_base_type), Record_Kind)
              && !Is_For_Access_Subtype (gnat_entity)
              && !Is_Unchecked_Union (gnat_base_type)
              && Is_Constrained (gnat_entity)
              && Stored_Constraint (gnat_entity) != No_Elist
              && Present (Discriminant_Constraint (gnat_entity)))
            {
              Entity_Id gnat_field;
              tree gnu_field_list = 0;
              tree gnu_pos_list
                = compute_field_positions (gnu_orig_type, NULL_TREE,
                                           size_zero_node, bitsize_zero_node,
                                           BIGGEST_ALIGNMENT);
              tree gnu_subst_list
                = substitution_list (gnat_entity, gnat_base_type, NULL_TREE,
                                     definition);
              tree gnu_temp;

              gnu_type = make_node (RECORD_TYPE);
              TYPE_NAME (gnu_type) = gnu_entity_id;
              TYPE_STUB_DECL (gnu_type)
                = create_type_decl (NULL_TREE, gnu_type, NULL, false, false,
                                    gnat_entity);
              TYPE_ALIGN (gnu_type) = TYPE_ALIGN (gnu_base_type);

              for (gnat_field = First_Entity (gnat_entity);
                   Present (gnat_field); gnat_field = Next_Entity (gnat_field))
                if ((Ekind (gnat_field) == E_Component
                     || Ekind (gnat_field) == E_Discriminant)
                    && (Underlying_Type (Scope (Original_Record_Component
                                                (gnat_field)))
                        == gnat_base_type)
                    && (No (Corresponding_Discriminant (gnat_field))
                        || !Is_Tagged_Type (gnat_base_type)))
                  {
                    tree gnu_old_field
                      = gnat_to_gnu_field_decl (Original_Record_Component
                                                (gnat_field));
                    tree gnu_offset
                      = TREE_VALUE (purpose_member (gnu_old_field,
                                                    gnu_pos_list));
                    tree gnu_pos = TREE_PURPOSE (gnu_offset);
                    tree gnu_bitpos = TREE_VALUE (TREE_VALUE (gnu_offset));
                    tree gnu_field_type
                      = gnat_to_gnu_type (Etype (gnat_field));
                    tree gnu_size = TYPE_SIZE (gnu_field_type);
                    tree gnu_new_pos = 0;
                    unsigned int offset_align
                      = tree_low_cst (TREE_PURPOSE (TREE_VALUE (gnu_offset)),
                                      1);
                    tree gnu_field;

                    /* If there was a component clause, the field types must be
                       the same for the type and subtype, so copy the data from
                       the old field to avoid recomputation here.  Also if the
                       field is justified modular and the optimization in
                       gnat_to_gnu_field was applied.  */
                    if (Present (Component_Clause
                                 (Original_Record_Component (gnat_field)))
                        || (TREE_CODE (gnu_field_type) == RECORD_TYPE
                            && TYPE_JUSTIFIED_MODULAR_P (gnu_field_type)
                            && TREE_TYPE (TYPE_FIELDS (gnu_field_type))
                               == TREE_TYPE (gnu_old_field)))
                      {
                        gnu_size = DECL_SIZE (gnu_old_field);
                        gnu_field_type = TREE_TYPE (gnu_old_field);
                      }

                    /* If this was a bitfield, get the size from the old field.
                       Also ensure the type can be placed into a bitfield.  */
                    else if (DECL_BIT_FIELD (gnu_old_field))
                      {
                        gnu_size = DECL_SIZE (gnu_old_field);
                        if (TYPE_MODE (gnu_field_type) == BLKmode
                            && TREE_CODE (gnu_field_type) == RECORD_TYPE
                            && host_integerp (TYPE_SIZE (gnu_field_type), 1))
                          gnu_field_type = make_packable_type (gnu_field_type);
                      }

                    if (CONTAINS_PLACEHOLDER_P (gnu_pos))
                      for (gnu_temp = gnu_subst_list;
                           gnu_temp; gnu_temp = TREE_CHAIN (gnu_temp))
                        gnu_pos = substitute_in_expr (gnu_pos,
                                                      TREE_PURPOSE (gnu_temp),
                                                      TREE_VALUE (gnu_temp));

                    /* If the size is now a constant, we can set it as the
                       size of the field when we make it.  Otherwise, we need
                       to deal with it specially.  */
                    if (TREE_CONSTANT (gnu_pos))
                      gnu_new_pos = bit_from_pos (gnu_pos, gnu_bitpos);

                    gnu_field
                      = create_field_decl
                        (DECL_NAME (gnu_old_field), gnu_field_type, gnu_type,
                         0, gnu_size, gnu_new_pos,
                         !DECL_NONADDRESSABLE_P (gnu_old_field));

                    if (!TREE_CONSTANT (gnu_pos))
                      {
                        normalize_offset (&gnu_pos, &gnu_bitpos, offset_align);
                        DECL_FIELD_OFFSET (gnu_field) = gnu_pos;
                        DECL_FIELD_BIT_OFFSET (gnu_field) = gnu_bitpos;
                        SET_DECL_OFFSET_ALIGN (gnu_field, offset_align);
                        DECL_SIZE (gnu_field) = gnu_size;
                        DECL_SIZE_UNIT (gnu_field)
                          = convert (sizetype,
                                     size_binop (CEIL_DIV_EXPR, gnu_size,
                                                 bitsize_unit_node));
                        layout_decl (gnu_field, DECL_OFFSET_ALIGN (gnu_field));
                      }

                    DECL_INTERNAL_P (gnu_field)
                      = DECL_INTERNAL_P (gnu_old_field);
                    SET_DECL_ORIGINAL_FIELD
                      (gnu_field, (DECL_ORIGINAL_FIELD (gnu_old_field)
                                   ? DECL_ORIGINAL_FIELD (gnu_old_field)
                                   : gnu_old_field));
                    DECL_DISCRIMINANT_NUMBER (gnu_field)
                      = DECL_DISCRIMINANT_NUMBER (gnu_old_field);
                    TREE_THIS_VOLATILE (gnu_field)
                      = TREE_THIS_VOLATILE (gnu_old_field);
                    TREE_CHAIN (gnu_field) = gnu_field_list;
                    gnu_field_list = gnu_field;
                    save_gnu_tree (gnat_field, gnu_field, false);
                  }

              /* Now go through the entities again looking for Itypes that
                 we have not elaborated but should (e.g., Etypes of fields
                 that have Original_Components).  */
              for (gnat_field = First_Entity (gnat_entity);
                   Present (gnat_field); gnat_field = Next_Entity (gnat_field))
                if ((Ekind (gnat_field) == E_Discriminant
                     || Ekind (gnat_field) == E_Component)
                    && !present_gnu_tree (Etype (gnat_field)))
                  gnat_to_gnu_entity (Etype (gnat_field), NULL_TREE, 0);

              finish_record_type (gnu_type, nreverse (gnu_field_list),
                                  true, false);

              /* Now set the size, alignment and alias set of the new type to
                 match that of the old one, doing any substitutions, as
                 above.  */
              TYPE_ALIGN (gnu_type) = TYPE_ALIGN (gnu_base_type);
              TYPE_SIZE (gnu_type) = TYPE_SIZE (gnu_base_type);
              TYPE_SIZE_UNIT (gnu_type) = TYPE_SIZE_UNIT (gnu_base_type);
              SET_TYPE_ADA_SIZE (gnu_type, TYPE_ADA_SIZE (gnu_base_type));
              copy_alias_set (gnu_type, gnu_base_type);

              if (CONTAINS_PLACEHOLDER_P (TYPE_SIZE (gnu_type)))
                for (gnu_temp = gnu_subst_list;
                     gnu_temp; gnu_temp = TREE_CHAIN (gnu_temp))
                  TYPE_SIZE (gnu_type)
                    = substitute_in_expr (TYPE_SIZE (gnu_type),
                                          TREE_PURPOSE (gnu_temp),
                                          TREE_VALUE (gnu_temp));

              if (CONTAINS_PLACEHOLDER_P (TYPE_SIZE_UNIT (gnu_type)))
                for (gnu_temp = gnu_subst_list;
                     gnu_temp; gnu_temp = TREE_CHAIN (gnu_temp))
                  TYPE_SIZE_UNIT (gnu_type)
                    = substitute_in_expr (TYPE_SIZE_UNIT (gnu_type),
                                          TREE_PURPOSE (gnu_temp),
                                          TREE_VALUE (gnu_temp));

              if (CONTAINS_PLACEHOLDER_P (TYPE_ADA_SIZE (gnu_type)))
                for (gnu_temp = gnu_subst_list;
                     gnu_temp; gnu_temp = TREE_CHAIN (gnu_temp))
                  SET_TYPE_ADA_SIZE
                    (gnu_type, substitute_in_expr (TYPE_ADA_SIZE (gnu_type),
                                                   TREE_PURPOSE (gnu_temp),
                                                   TREE_VALUE (gnu_temp)));

              /* Recompute the mode of this record type now that we know its
                 actual size.  */
              compute_record_mode (gnu_type);

              /* Reapply variable_size since we have changed the sizes.  */
              TYPE_SIZE (gnu_type) = variable_size (TYPE_SIZE (gnu_type));
              TYPE_SIZE_UNIT (gnu_type)
                = variable_size (TYPE_SIZE_UNIT (gnu_type));

              /* Fill in locations of fields.  */
              annotate_rep (gnat_entity, gnu_type);
            }

          /* If we've made a new type, record it and make an XVS type to show
             what this is a subtype of.  Some debuggers require the  XVS
             type to be output first, so do it in that order.  */
          if (gnu_type != gnu_orig_type)
            {
              if (debug_info_p)
                {
                  tree gnu_subtype_marker = make_node (RECORD_TYPE);
                  tree gnu_orig_name = TYPE_NAME (gnu_orig_type);

                  if (TREE_CODE (gnu_orig_name) == TYPE_DECL)
                    gnu_orig_name = DECL_NAME (gnu_orig_name);

                  TYPE_NAME (gnu_subtype_marker)
                    = create_concat_name (gnat_entity, "XVS");
                  finish_record_type (gnu_subtype_marker,
                                      create_field_decl (gnu_orig_name,
                                                         integer_type_node,
                                                         gnu_subtype_marker,
                                                         0, NULL_TREE,
                                                         NULL_TREE, 0),
                                      false, false);
                }

              TYPE_VOLATILE (gnu_type) = Treat_As_Volatile (gnat_entity);
              TYPE_NAME (gnu_type) = gnu_entity_id;
              TYPE_STUB_DECL (gnu_type)
                = create_type_decl (TYPE_NAME (gnu_type), gnu_type,
                                    NULL, true, debug_info_p, gnat_entity);
            }

          /* Otherwise, go down all the components in the new type and
             make them equivalent to those in the base type.  */
          else
            for (gnat_temp = First_Entity (gnat_entity); Present (gnat_temp);
                 gnat_temp = Next_Entity (gnat_temp))
              if ((Ekind (gnat_temp) == E_Discriminant
                   && !Is_Unchecked_Union (gnat_base_type))
                  || Ekind (gnat_temp) == E_Component)
                save_gnu_tree (gnat_temp,
                               gnat_to_gnu_field_decl
                               (Original_Record_Component (gnat_temp)), false);
        }
      break;

    case E_Access_Subprogram_Type:
    case E_Anonymous_Access_Subprogram_Type:
      /* If we are not defining this entity, and we have incomplete
         entities being processed above us, make a dummy type and
         fill it in later.  */
      if (!definition && defer_incomplete_level != 0)
        {
          struct incomplete *p
            = (struct incomplete *) xmalloc (sizeof (struct incomplete));

          gnu_type
            = build_pointer_type
              (make_dummy_type (Directly_Designated_Type (gnat_entity)));
          gnu_decl = create_type_decl (gnu_entity_id, gnu_type, attr_list,
                                       !Comes_From_Source (gnat_entity),
                                       debug_info_p, gnat_entity);
          save_gnu_tree (gnat_entity, gnu_decl, false);
          this_made_decl = saved = true;

          p->old_type = TREE_TYPE (gnu_type);
          p->full_type = Directly_Designated_Type (gnat_entity);
          p->next = defer_incomplete_list;
          defer_incomplete_list = p;
          break;
        }

      /* ... fall through ... */

    case E_Allocator_Type:
    case E_Access_Type:
    case E_Access_Attribute_Type:
    case E_Anonymous_Access_Type:
    case E_General_Access_Type:
      {
        Entity_Id gnat_desig_type = Directly_Designated_Type (gnat_entity);
        /* Get the "full view" of this entity.  If this is an incomplete
           entity from a limited with, treat its non-limited view as the
           full view.  Otherwise, if this is an incomplete or private
           type, use the full view.  */
        Entity_Id gnat_desig_full
          = (IN (Ekind (gnat_desig_type), Incomplete_Kind)
             && From_With_Type (gnat_desig_type))
            ? Non_Limited_View (gnat_desig_type)
            : IN (Ekind (gnat_desig_type), Incomplete_Or_Private_Kind)
              ? Full_View (gnat_desig_type)
              : Empty;
        /* We want to know if we'll be seeing the freeze node for any
           incomplete type we may be pointing to.  */
        bool in_main_unit
          = (Present (gnat_desig_full)
             ? In_Extended_Main_Code_Unit (gnat_desig_full)
             : In_Extended_Main_Code_Unit (gnat_desig_type));
        bool got_fat_p = false;
        bool made_dummy = false;
        tree gnu_desig_type = NULL_TREE;
        enum machine_mode p_mode = mode_for_size (esize, MODE_INT, 0);

        if (!targetm.valid_pointer_mode (p_mode))
          p_mode = ptr_mode;

        if (No (gnat_desig_full)
            && (Ekind (gnat_desig_type) == E_Class_Wide_Type
                || (Ekind (gnat_desig_type) == E_Class_Wide_Subtype
                    && Present (Equivalent_Type (gnat_desig_type)))))
          {
            if (Present (Equivalent_Type (gnat_desig_type)))
              {
                gnat_desig_full = Equivalent_Type (gnat_desig_type);
                if (IN (Ekind (gnat_desig_full), Incomplete_Or_Private_Kind))
                  gnat_desig_full = Full_View (gnat_desig_full);
              }
            else if (IN (Ekind (Root_Type (gnat_desig_type)),
                         Incomplete_Or_Private_Kind))
              gnat_desig_full = Full_View (Root_Type (gnat_desig_type));
          }

        if (Present (gnat_desig_full) && Is_Concurrent_Type (gnat_desig_full))
          gnat_desig_full = Corresponding_Record_Type (gnat_desig_full);

        /* If either the designated type or its full view is an
           unconstrained array subtype, replace it with the type it's a
           subtype of.  This avoids problems with multiple copies of
           unconstrained array types.  */
        if (Ekind (gnat_desig_type) == E_Array_Subtype
            && !Is_Constrained (gnat_desig_type))
          gnat_desig_type = Etype (gnat_desig_type);
        if (Present (gnat_desig_full)
            && Ekind (gnat_desig_full) == E_Array_Subtype
            && !Is_Constrained (gnat_desig_full))
          gnat_desig_full = Etype (gnat_desig_full);

        /* If the designated type is a subtype of an incomplete record type,
           use the parent type to avoid order of elaboration issues.  This
           can lose some code efficiency, but there is no alternative.  */
        if (Present (gnat_desig_full)
             && Ekind (gnat_desig_full) == E_Record_Subtype
             && Ekind (Etype (gnat_desig_full)) == E_Record_Type)
          gnat_desig_full = Etype (gnat_desig_full);

        /* If we are pointing to an incomplete type whose completion is an
           unconstrained array, make a fat pointer type instead of a pointer
           to VOID.  The two types in our fields will be pointers to VOID and
           will be replaced in update_pointer_to.  Similarly, if the type
           itself is a dummy type or an unconstrained array.  Also make
           a dummy TYPE_OBJECT_RECORD_TYPE in case we have any thin
           pointers to it.  */

        if ((Present (gnat_desig_full)
             && Is_Array_Type (gnat_desig_full)
             && !Is_Constrained (gnat_desig_full))
            || (present_gnu_tree (gnat_desig_type)
                && TYPE_IS_DUMMY_P (TREE_TYPE
                                     (get_gnu_tree (gnat_desig_type)))
                && Is_Array_Type (gnat_desig_type)
                && !Is_Constrained (gnat_desig_type))
            || (present_gnu_tree (gnat_desig_type)
                && (TREE_CODE (TREE_TYPE (get_gnu_tree (gnat_desig_type)))
                    == UNCONSTRAINED_ARRAY_TYPE)
                && !(TYPE_POINTER_TO (TREE_TYPE
                                     (get_gnu_tree (gnat_desig_type)))))
            || (No (gnat_desig_full) && !in_main_unit
                && defer_incomplete_level
                && !present_gnu_tree (gnat_desig_type)
                && Is_Array_Type (gnat_desig_type)
                && ! Is_Constrained (gnat_desig_type))
            || (in_main_unit && From_With_Type (gnat_entity)
                && (Present (gnat_desig_full)
                    ? Present (Freeze_Node (gnat_desig_full))
                    : Present (Freeze_Node (gnat_desig_type)))
                && Is_Array_Type (gnat_desig_type)
                && !Is_Constrained (gnat_desig_type)))
          {
            tree gnu_old
              = (present_gnu_tree (gnat_desig_type)
                 ? gnat_to_gnu_type (gnat_desig_type)
                 : make_dummy_type (gnat_desig_type));
            tree fields;

            /* Show the dummy we get will be a fat pointer.  */
            got_fat_p = made_dummy = true;

            /* If the call above got something that has a pointer, that
               pointer is our type.  This could have happened either
               because the type was elaborated or because somebody
               else executed the code below.  */
            gnu_type = TYPE_POINTER_TO (gnu_old);
            if (!gnu_type)
              {
                gnu_type = make_node (RECORD_TYPE);
                SET_TYPE_UNCONSTRAINED_ARRAY (gnu_type, gnu_old);
                TYPE_POINTER_TO (gnu_old) = gnu_type;

                Sloc_to_locus (Sloc (gnat_entity), &input_location);
                fields
                  = chainon (chainon (NULL_TREE,
                                      create_field_decl
                                      (get_identifier ("P_ARRAY"),
                                       ptr_void_type_node, gnu_type,
                                       0, 0, 0, 0)),
                             create_field_decl (get_identifier ("P_BOUNDS"),
                                                ptr_void_type_node,
                                                gnu_type, 0, 0, 0, 0));

                /* Make sure we can place this into a register.  */
                TYPE_ALIGN (gnu_type)
                  = MIN (BIGGEST_ALIGNMENT, 2 * POINTER_SIZE);
                TYPE_IS_FAT_POINTER_P (gnu_type) = 1;
                finish_record_type (gnu_type, fields, false, true);

                TYPE_OBJECT_RECORD_TYPE (gnu_old) = make_node (RECORD_TYPE);
                TYPE_NAME (TYPE_OBJECT_RECORD_TYPE (gnu_old))
                  = concat_id_with_name (get_entity_name (gnat_desig_type),
                                         "XUT");
                TYPE_DUMMY_P (TYPE_OBJECT_RECORD_TYPE (gnu_old)) = 1;
              }
          }

        /* If we already know what the full type is, use it.  */
        else if (Present (gnat_desig_full)
                 && present_gnu_tree (gnat_desig_full))
          gnu_desig_type = TREE_TYPE (get_gnu_tree (gnat_desig_full));

        /* Get the type of the thing we are to point to and build a pointer
           to it.  If it is a reference to an incomplete or private type with a
           full view that is a record, make a dummy type node and get the
           actual type later when we have verified it is safe.  */
        else if (!in_main_unit
                 && !present_gnu_tree (gnat_desig_type)
                 && Present (gnat_desig_full)
                 && !present_gnu_tree (gnat_desig_full)
                 && Is_Record_Type (gnat_desig_full))
          {
            gnu_desig_type = make_dummy_type (gnat_desig_type);
            made_dummy = true;
          }

        /* Likewise if we are pointing to a record or array and we are to defer
           elaborating incomplete types.  We do this since this access type
           may be the full view of some private type.  Note that the
           unconstrained array case is handled above. */
        else if ((!in_main_unit || imported_p) && defer_incomplete_level != 0
                 && !present_gnu_tree (gnat_desig_type)
                 && ((Is_Record_Type (gnat_desig_type)
                      || Is_Array_Type (gnat_desig_type))
                     || (Present (gnat_desig_full)
                         && (Is_Record_Type (gnat_desig_full)
                             || Is_Array_Type (gnat_desig_full)))))
          {
            gnu_desig_type = make_dummy_type (gnat_desig_type);
            made_dummy = true;
          }

        /* If this is a reference from a limited_with type back to our
           main unit and there's a Freeze_Node for it, either we have
           already processed the declaration and made the dummy type,
           in which case we just reuse the latter, or we have not yet,
           in which case we make the dummy type and it will be reused
           when the declaration is processed.  In both cases, the pointer
           eventually created below will be automatically adjusted when
           the Freeze_Node is processed.  Note that the unconstrained
           array case is handled above. */
        else if (in_main_unit && From_With_Type (gnat_entity)
                 && (Present (gnat_desig_full)
                     ? Present (Freeze_Node (gnat_desig_full))
                     : Present (Freeze_Node (gnat_desig_type))))
          {
            gnu_desig_type = make_dummy_type (gnat_desig_type);
            made_dummy = true;
          }

        else if (gnat_desig_type == gnat_entity)
          {
            gnu_type
              = build_pointer_type_for_mode (make_node (VOID_TYPE),
                                             p_mode,
                                             No_Strict_Aliasing (gnat_entity));
            TREE_TYPE (gnu_type) = TYPE_POINTER_TO (gnu_type) = gnu_type;
          }

        else
          gnu_desig_type = gnat_to_gnu_type (gnat_desig_type);

        /* It is possible that the above call to gnat_to_gnu_type resolved our
           type.  If so, just return it.  */
        if (present_gnu_tree (gnat_entity))
          {
            maybe_present = true;
            break;
          }

        /* If we have a GCC type for the designated type, possibly modify it
           if we are pointing only to constant objects and then make a pointer
           to it.  Don't do this for unconstrained arrays.  */
        if (!gnu_type && gnu_desig_type)
          {
            if (Is_Access_Constant (gnat_entity)
                && TREE_CODE (gnu_desig_type) != UNCONSTRAINED_ARRAY_TYPE)
              {
                gnu_desig_type
                  = build_qualified_type
                    (gnu_desig_type,
                     TYPE_QUALS (gnu_desig_type) | TYPE_QUAL_CONST);

                /* Some extra processing is required if we are building a
                   pointer to an incomplete type (in the GCC sense). We might
                   have such a type if we just made a dummy, or directly out
                   of the call to gnat_to_gnu_type above if we are processing
                   an access type for a record component designating the
                   record type itself.  */
                if (TYPE_MODE (gnu_desig_type) == VOIDmode)
                  {
                    /* We must ensure that the pointer to variant we make will
                       be processed by update_pointer_to when the initial type
                       is completed. Pretend we made a dummy and let further
                       processing act as usual.  */
                    made_dummy = true;

                    /* We must ensure that update_pointer_to will not retrieve
                       the dummy variant when building a properly qualified
                       version of the complete type. We take advantage of the
                       fact that get_qualified_type is requiring TYPE_NAMEs to
                       match to influence build_qualified_type and then also
                       update_pointer_to here. */
                    TYPE_NAME (gnu_desig_type)
                      = create_concat_name (gnat_desig_type, "INCOMPLETE_CST");
                  }
              }

            gnu_type
              = build_pointer_type_for_mode (gnu_desig_type, p_mode,
                                             No_Strict_Aliasing (gnat_entity));
          }

        /* If we are not defining this object and we made a dummy pointer,
           save our current definition, evaluate the actual type, and replace
           the tentative type we made with the actual one.  If we are to defer
           actually looking up the actual type, make an entry in the
           deferred list.  */

        if (!in_main_unit && made_dummy)
          {
            tree gnu_old_type
              = TYPE_FAT_POINTER_P (gnu_type)
                ? TYPE_UNCONSTRAINED_ARRAY (gnu_type) : TREE_TYPE (gnu_type);

            if (esize == POINTER_SIZE
                && (got_fat_p || TYPE_FAT_POINTER_P (gnu_type)))
              gnu_type
                = build_pointer_type
                  (TYPE_OBJECT_RECORD_TYPE
                   (TYPE_UNCONSTRAINED_ARRAY (gnu_type)));

            gnu_decl = create_type_decl (gnu_entity_id, gnu_type, attr_list,
                                         !Comes_From_Source (gnat_entity),
                                         debug_info_p, gnat_entity);
            save_gnu_tree (gnat_entity, gnu_decl, false);
            this_made_decl = saved = true;

            if (defer_incomplete_level == 0)
              /* Note that the call to gnat_to_gnu_type here might have
                 updated gnu_old_type directly, in which case it is not a
                 dummy type any more when we get into update_pointer_to.

                 This may happen for instance when the designated type is a
                 record type, because their elaboration starts with an
                 initial node from make_dummy_type, which may yield the same
                 node as the one we got.

                 Besides, variants of this non-dummy type might have been
                 created along the way. update_pointer_to is expected to
                 properly take care of those situations.  */
              update_pointer_to (TYPE_MAIN_VARIANT (gnu_old_type),
                                 gnat_to_gnu_type (gnat_desig_type));
            else
              {
                struct incomplete *p
                  = (struct incomplete *) xmalloc (sizeof (struct incomplete));

                p->old_type = gnu_old_type;
                p->full_type = gnat_desig_type;
                p->next = defer_incomplete_list;
                defer_incomplete_list = p;
              }
          }
      }
      break;

    case E_Access_Protected_Subprogram_Type:
    case E_Anonymous_Access_Protected_Subprogram_Type:
      if (type_annotate_only && No (Equivalent_Type (gnat_entity)))
        gnu_type = build_pointer_type (void_type_node);
      else
        {
          /* The runtime representation is the equivalent type. */
          gnu_type = gnat_to_gnu_type (Equivalent_Type (gnat_entity));
          maybe_present = 1;
        }

      if (Is_Itype (Directly_Designated_Type (gnat_entity))
          && !present_gnu_tree (Directly_Designated_Type (gnat_entity))
          && No (Freeze_Node (Directly_Designated_Type (gnat_entity)))
          && !Is_Record_Type (Scope (Directly_Designated_Type (gnat_entity))))
        gnat_to_gnu_entity (Directly_Designated_Type (gnat_entity),
                            NULL_TREE, 0);

      break;

    case E_Access_Subtype:

      /* We treat this as identical to its base type; any constraint is
         meaningful only to the front end.

         The designated type must be elaborated as well, if it does
         not have its own freeze node. Designated (sub)types created
         for constrained components of records with discriminants are
         not frozen by the front end and thus not elaborated by gigi,
         because their use may appear before the base type is frozen,
         and because it is not clear that they are needed anywhere in
         Gigi. With the current model, there is no correct place where
         they could be elaborated.  */

      gnu_type = gnat_to_gnu_type (Etype (gnat_entity));
      if (Is_Itype (Directly_Designated_Type (gnat_entity))
          && !present_gnu_tree (Directly_Designated_Type (gnat_entity))
          && Is_Frozen (Directly_Designated_Type (gnat_entity))
          && No (Freeze_Node (Directly_Designated_Type (gnat_entity))))
        {
          /* If we are not defining this entity, and we have incomplete
             entities being processed above us, make a dummy type and
             elaborate it later.  */
          if (!definition && defer_incomplete_level != 0)
            {
              struct incomplete *p
                = (struct incomplete *) xmalloc (sizeof (struct incomplete));
              tree gnu_ptr_type
                = build_pointer_type
                  (make_dummy_type (Directly_Designated_Type (gnat_entity)));

              p->old_type = TREE_TYPE (gnu_ptr_type);
              p->full_type = Directly_Designated_Type (gnat_entity);
              p->next = defer_incomplete_list;
              defer_incomplete_list = p;
            }
          else if (IN (Ekind (Base_Type
                              (Directly_Designated_Type (gnat_entity))),
                       Incomplete_Or_Private_Kind))
            ;
          else
            gnat_to_gnu_entity (Directly_Designated_Type (gnat_entity),
                                NULL_TREE, 0);
        }

      maybe_present = true;
      break;

    /* Subprogram Entities

       The following access functions are defined for subprograms (functions
       or procedures):

                First_Formal    The first formal parameter.
                Is_Imported     Indicates that the subprogram has appeared in
                                an INTERFACE or IMPORT pragma. For now we
                                assume that the external language is C.
                Is_Inlined      True if the subprogram is to be inlined.

       In addition for function subprograms we have:

                Etype           Return type of the function.

       Each parameter is first checked by calling must_pass_by_ref on its
       type to determine if it is passed by reference.  For parameters which
       are copied in, if they are Ada IN OUT or OUT parameters, their return
       value becomes part of a record which becomes the return type of the
       function (C function - note that this applies only to Ada procedures
       so there is no Ada return type). Additional code to store back the
       parameters will be generated on the caller side.  This transformation
       is done here, not in the front-end.

       The intended result of the transformation can be seen from the
       equivalent source rewritings that follow:

                                                   struct temp {int a,b};
       procedure P (A,B: IN OUT ...) is            temp P (int A,B) {
        ..                                            ..
       end P;                                        return {A,B};
                                                   }
                              procedure call

                                              {
                                                  temp t;
       P(X,Y);                                    t = P(X,Y);
                                                  X = t.a , Y = t.b;
                                              }

       For subprogram types we need to perform mainly the same conversions to
       GCC form that are needed for procedures and function declarations.  The
       only difference is that at the end, we make a type declaration instead
       of a function declaration.  */

    case E_Subprogram_Type:
    case E_Function:
    case E_Procedure:
      {
        /* The first GCC parameter declaration (a PARM_DECL node).  The
           PARM_DECL nodes are chained through the TREE_CHAIN field, so this
           actually is the head of this parameter list.  */
        tree gnu_param_list = NULL_TREE;
        /* The type returned by a function. If the subprogram is a procedure
           this type should be void_type_node.  */
        tree gnu_return_type = void_type_node;
        /* List of fields in return type of procedure with copy in copy out
           parameters.  */
        tree gnu_field_list = NULL_TREE;
        /* Non-null for subprograms containing  parameters passed by copy in
           copy out (Ada IN OUT or OUT parameters not passed by reference),
           in which case it is the list of nodes used to specify the values of
           the in out/out parameters that are returned as a record upon
           procedure return.  The TREE_PURPOSE of an element of this list is
           a field of the record and the TREE_VALUE is the PARM_DECL
           corresponding to that field.  This list will be saved in the
           TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create.  */
        tree gnu_return_list = NULL_TREE;
        /* If an import pragma asks to map this subprogram to a GCC builtin,
           this is the builtin DECL node.  */
        tree gnu_builtin_decl = NULL_TREE;
        Entity_Id gnat_param;
        bool inline_flag = Is_Inlined (gnat_entity);
        bool public_flag = Is_Public (gnat_entity);
        bool extern_flag
          = (Is_Public (gnat_entity) && !definition) || imported_p;
        bool pure_flag = Is_Pure (gnat_entity);
        bool volatile_flag = No_Return (gnat_entity);
        bool returns_by_ref = false;
        bool returns_unconstrained = false;
        bool returns_by_target_ptr = false;
        tree gnu_ext_name = create_concat_name (gnat_entity, 0);
        bool has_copy_in_out = false;
        int parmnum;

        if (kind == E_Subprogram_Type && !definition)
          /* A parameter may refer to this type, so defer completion
             of any incomplete types.  */
          defer_incomplete_level++, this_deferred = true;

        /* If the subprogram has an alias, it is probably inherited, so
           we can use the original one.  If the original "subprogram"
           is actually an enumeration literal, it may be the first use
           of its type, so we must elaborate that type now.  */
        if (Present (Alias (gnat_entity)))
          {
            if (Ekind (Alias (gnat_entity)) == E_Enumeration_Literal)
              gnat_to_gnu_entity (Etype (Alias (gnat_entity)), NULL_TREE, 0);

            gnu_decl = gnat_to_gnu_entity (Alias (gnat_entity),
                                           gnu_expr, 0);

            /* Elaborate any Itypes in the parameters of this entity.  */
            for (gnat_temp = First_Formal_With_Extras (gnat_entity);
                 Present (gnat_temp);
                 gnat_temp = Next_Formal_With_Extras (gnat_temp))
              if (Is_Itype (Etype (gnat_temp)))
                gnat_to_gnu_entity (Etype (gnat_temp), NULL_TREE, 0);

            break;
          }

        /* If this subprogram is expectedly bound to a GCC builtin, fetch the
           corresponding DECL node.

           We still want the parameter associations to take place because the
           proper generation of calls depends on it (a GNAT parameter without
           a corresponding GCC tree has a very specific meaning), so we don't
           just break here.  */
        if (Convention (gnat_entity) == Convention_Intrinsic)
          gnu_builtin_decl = builtin_decl_for (gnu_ext_name);

        /* ??? What if we don't find the builtin node above ? warn ? err ?
           In the current state we neither warn nor err, and calls will just
           be handled as for regular subprograms. */

        if (kind == E_Function || kind == E_Subprogram_Type)
          gnu_return_type = gnat_to_gnu_type (Etype (gnat_entity));

        /* If this function returns by reference, make the actual
           return type of this function the pointer and mark the decl.  */
        if (Returns_By_Ref (gnat_entity))
          {
            returns_by_ref = true;
            gnu_return_type = build_pointer_type (gnu_return_type);
          }

        /* If the Mechanism is By_Reference, ensure the return type uses
           the machine's by-reference mechanism, which may not the same
           as above (e.g., it might be by passing a fake parameter).  */
        else if (kind == E_Function
                 && Mechanism (gnat_entity) == By_Reference)
          {
            TREE_ADDRESSABLE (gnu_return_type) = 1;

            /* We expect this bit to be reset by gigi shortly, so can avoid a
               type node copy here.  This actually also prevents troubles with
               the generation of debug information for the function, because
               we might have issued such info for this type already, and would
               be attaching a distinct type node to the function if we made a
               copy here.  */
          }

        /* If we are supposed to return an unconstrained array,
           actually return a fat pointer and make a note of that.  Return
           a pointer to an unconstrained record of variable size.  */
        else if (TREE_CODE (gnu_return_type) == UNCONSTRAINED_ARRAY_TYPE)
          {
            gnu_return_type = TREE_TYPE (gnu_return_type);
            returns_unconstrained = true;
          }

        /* If the type requires a transient scope, the result is allocated
           on the secondary stack, so the result type of the function is
           just a pointer.  */
        else if (Requires_Transient_Scope (Etype (gnat_entity)))
          {
            gnu_return_type = build_pointer_type (gnu_return_type);
            returns_unconstrained = true;
          }

        /* If the type is a padded type and the underlying type would not
           be passed by reference or this function has a foreign convention,
           return the underlying type.  */
        else if (TREE_CODE (gnu_return_type) == RECORD_TYPE
                 && TYPE_IS_PADDING_P (gnu_return_type)
                 && (!default_pass_by_ref (TREE_TYPE
                                           (TYPE_FIELDS (gnu_return_type)))
                     || Has_Foreign_Convention (gnat_entity)))
          gnu_return_type = TREE_TYPE (TYPE_FIELDS (gnu_return_type));

        /* If the return type is unconstrained, that means it must have a
           maximum size.  We convert the function into a procedure and its
           caller will pass a pointer to an object of that maximum size as the
           first parameter when we call the function.  */
        if (CONTAINS_PLACEHOLDER_P (TYPE_SIZE (gnu_return_type)))
          {
            returns_by_target_ptr = true;
            gnu_param_list
              = create_param_decl (get_identifier ("TARGET"),
                                   build_reference_type (gnu_return_type),
                                   true);
            gnu_return_type = void_type_node;
          }

        /* If the return type has a size that overflows, we cannot have
           a function that returns that type.  This usage doesn't make
           sense anyway, so give an error here.  */
        if (TYPE_SIZE_UNIT (gnu_return_type)
            && TREE_CONSTANT (TYPE_SIZE_UNIT (gnu_return_type))
            && TREE_OVERFLOW (TYPE_SIZE_UNIT (gnu_return_type)))
          {
            post_error ("cannot return type whose size overflows",
                        gnat_entity);
            gnu_return_type = copy_node (gnu_return_type);
            TYPE_SIZE (gnu_return_type) = bitsize_zero_node;
            TYPE_SIZE_UNIT (gnu_return_type) = size_zero_node;
            TYPE_MAIN_VARIANT (gnu_return_type) = gnu_return_type;
            TYPE_NEXT_VARIANT (gnu_return_type) = NULL_TREE;
          }

        /* Look at all our parameters and get the type of
           each.  While doing this, build a copy-out structure if
           we need one.  */

        for (gnat_param = First_Formal_With_Extras (gnat_entity), parmnum = 0;
             Present (gnat_param);
             gnat_param = Next_Formal_With_Extras (gnat_param), parmnum++)
          {
            tree gnu_param_name = get_entity_name (gnat_param);
            tree gnu_param_type = gnat_to_gnu_type (Etype (gnat_param));
            tree gnu_param, gnu_field;
            bool by_ref_p = false;
            bool by_descr_p = false;
            bool by_component_ptr_p = false;
            bool copy_in_copy_out_flag = false;
            bool req_by_copy = false, req_by_ref = false;

            /* Builtins are expanded inline and there is no real call sequence
               involved. so the type expected by the underlying expander is
               always the type of each argument "as is".  */
            if (gnu_builtin_decl)
              req_by_copy = 1;

            /* Otherwise, see if a Mechanism was supplied that forced this
               parameter to be passed one way or another.  */
            else if (Is_Valued_Procedure (gnat_entity) && parmnum == 0)
              req_by_copy = true;
            else if (Mechanism (gnat_param) == Default)
              ;
            else if (Mechanism (gnat_param) == By_Copy)
              req_by_copy = true;
            else if (Mechanism (gnat_param) == By_Reference)
              req_by_ref = true;
            else if (Mechanism (gnat_param) <= By_Descriptor)
              by_descr_p = true;
            else if (Mechanism (gnat_param) > 0)
              {
                if (TREE_CODE (gnu_param_type) == UNCONSTRAINED_ARRAY_TYPE
                    || TREE_CODE (TYPE_SIZE (gnu_param_type)) != INTEGER_CST
                    || 0 < compare_tree_int (TYPE_SIZE (gnu_param_type),
                                             Mechanism (gnat_param)))
                  req_by_ref = true;
                else
                  req_by_copy = true;
              }
            else
              post_error ("unsupported mechanism for&", gnat_param);

            /* If this is either a foreign function or if the
               underlying type won't be passed by reference, strip off
               possible padding type.  */
            if (TREE_CODE (gnu_param_type) == RECORD_TYPE
                && TYPE_IS_PADDING_P (gnu_param_type)
                && (req_by_ref || Has_Foreign_Convention (gnat_entity)
                    || (!must_pass_by_ref (TREE_TYPE (TYPE_FIELDS
                                                      (gnu_param_type)))
                        && (req_by_copy
                            || !default_pass_by_ref (TREE_TYPE
                                                      (TYPE_FIELDS
                                                       (gnu_param_type)))))))
              gnu_param_type = TREE_TYPE (TYPE_FIELDS (gnu_param_type));

            /* If this is an IN parameter it is read-only, so make a variant
               of the type that is read-only.

               ??? However, if this is an unconstrained array, that type can
               be very complex.  So skip it for now.  Likewise for any other
               self-referential type.  */
            if (Ekind (gnat_param) == E_In_Parameter
                && TREE_CODE (gnu_param_type) != UNCONSTRAINED_ARRAY_TYPE
                && !CONTAINS_PLACEHOLDER_P (TYPE_SIZE (gnu_param_type)))
              gnu_param_type
                = build_qualified_type (gnu_param_type,
                                        (TYPE_QUALS (gnu_param_type)
                                         | TYPE_QUAL_CONST));

            /* For foreign conventions, pass arrays as a pointer to the
               underlying type.  First check for unconstrained array and get
               the underlying array.  Then get the component type and build
               a pointer to it.  */
            if (Has_Foreign_Convention (gnat_entity)
                && TREE_CODE (gnu_param_type) == UNCONSTRAINED_ARRAY_TYPE)
              gnu_param_type
                = TREE_TYPE (TREE_TYPE (TYPE_FIELDS
                                        (TREE_TYPE (gnu_param_type))));

            if (by_descr_p)
              gnu_param_type
                = build_pointer_type
                  (build_vms_descriptor (gnu_param_type,
                                         Mechanism (gnat_param), gnat_entity));

            else if (Has_Foreign_Convention (gnat_entity)
                     && !req_by_copy
                     && TREE_CODE (gnu_param_type) == ARRAY_TYPE)
              {
                /* Strip off any multi-dimensional entries, then strip
                   off the last array to get the component type.  */
                while (TREE_CODE (TREE_TYPE (gnu_param_type)) == ARRAY_TYPE
                       && TYPE_MULTI_ARRAY_P (TREE_TYPE (gnu_param_type)))
                  gnu_param_type = TREE_TYPE (gnu_param_type);

                by_component_ptr_p = true;
                gnu_param_type = TREE_TYPE (gnu_param_type);

                if (Ekind (gnat_param) == E_In_Parameter)
                  gnu_param_type
                    = build_qualified_type (gnu_param_type,
                                            (TYPE_QUALS (gnu_param_type)
                                             | TYPE_QUAL_CONST));

                gnu_param_type = build_pointer_type (gnu_param_type);
              }

            /* Fat pointers are passed as thin pointers for foreign
               conventions.  */
            else if (Has_Foreign_Convention (gnat_entity)
                     && TYPE_FAT_POINTER_P (gnu_param_type))
              gnu_param_type
                = make_type_from_size (gnu_param_type,
                                       size_int (POINTER_SIZE), false);

            /* If we must pass or were requested to pass by reference, do so.
               If we were requested to pass by copy, do so.
               Otherwise, for foreign conventions, pass all in out parameters
               or aggregates by reference.  For COBOL and Fortran, pass
               all integer and FP types that way too.  For Convention Ada,
               use the standard Ada default.  */
            else if (must_pass_by_ref (gnu_param_type) || req_by_ref
                     || (!req_by_copy
                         && ((Has_Foreign_Convention (gnat_entity)
                              && (Ekind (gnat_param) != E_In_Parameter
                                  || AGGREGATE_TYPE_P (gnu_param_type)))
                             || (((Convention (gnat_entity)
                                   == Convention_Fortran)
                                  || (Convention (gnat_entity)
                                      == Convention_COBOL))
                                 && (INTEGRAL_TYPE_P (gnu_param_type)
                                     || FLOAT_TYPE_P (gnu_param_type)))
                             /* For convention Ada, see if we pass by reference
                                by default.  */
                             || (!Has_Foreign_Convention (gnat_entity)
                                 && default_pass_by_ref (gnu_param_type)))))
              {
                gnu_param_type = build_reference_type (gnu_param_type);
                by_ref_p = true;
              }

            else if (Ekind (gnat_param) != E_In_Parameter)
              copy_in_copy_out_flag = true;

            if (req_by_copy && (by_ref_p || by_component_ptr_p))
              post_error ("?cannot pass & by copy", gnat_param);

            /* If this is an OUT parameter that isn't passed by reference
               and isn't a pointer or aggregate, we don't make a PARM_DECL
               for it.  Instead, it will be a VAR_DECL created when we process
               the procedure.  For the special parameter of Valued_Procedure,
               never pass it in.

               An exception is made to cover the RM-6.4.1 rule requiring "by
               copy" out parameters with discriminants or implicit initial
               values to be handled like in out parameters. These type are
               normally built as aggregates, and hence passed by reference,
               except for some packed arrays which end up encoded in special
               integer types.

               The exception we need to make is then for packed arrays of
               records with discriminants or implicit initial values. We have
               no light/easy way to check for the latter case, so we merely
               check for packed arrays of records. This may lead to useless
               copy-in operations, but in very rare cases only, as these would
               be exceptions in a set of already exceptional situations.  */
            if (Ekind (gnat_param) == E_Out_Parameter && !by_ref_p
                && ((Is_Valued_Procedure (gnat_entity) && parmnum == 0)
                    || (!by_descr_p
                        && !POINTER_TYPE_P (gnu_param_type)
                        && !AGGREGATE_TYPE_P (gnu_param_type)))
                && !(Is_Array_Type (Etype (gnat_param))
                     && Is_Packed (Etype (gnat_param))
                     && Is_Composite_Type (Component_Type
                                           (Etype (gnat_param)))))
              gnu_param = NULL_TREE;
            else
              {
                gnu_param
                  = create_param_decl
                    (gnu_param_name, gnu_param_type,
                     by_ref_p || by_component_ptr_p
                     || Ekind (gnat_param) == E_In_Parameter);

                DECL_BY_REF_P (gnu_param) = by_ref_p;
                DECL_BY_COMPONENT_PTR_P (gnu_param) = by_component_ptr_p;
                DECL_BY_DESCRIPTOR_P (gnu_param) = by_descr_p;
                DECL_POINTS_TO_READONLY_P (gnu_param)
                  = (Ekind (gnat_param) == E_In_Parameter
                     && (by_ref_p || by_component_ptr_p));
                Sloc_to_locus (Sloc (gnat_param),
                               &DECL_SOURCE_LOCATION (gnu_param));
                save_gnu_tree (gnat_param, gnu_param, false);
                gnu_param_list = chainon (gnu_param, gnu_param_list);

                /* If a parameter is a pointer, this function may modify
                   memory through it and thus shouldn't be considered
                   a pure function.  Also, the memory may be modified
                   between two calls, so they can't be CSE'ed.  The latter
                   case also handles by-ref parameters.  */
                if (POINTER_TYPE_P (gnu_param_type)
                    ||  TYPE_FAT_POINTER_P (gnu_param_type))
                  pure_flag = false;
              }

            if (copy_in_copy_out_flag)
              {
                if (!has_copy_in_out)
                  {
                    gcc_assert (TREE_CODE (gnu_return_type) == VOID_TYPE);
                    gnu_return_type = make_node (RECORD_TYPE);
                    TYPE_NAME (gnu_return_type) = get_identifier ("RETURN");
                    has_copy_in_out = true;
                  }

                gnu_field = create_field_decl (gnu_param_name, gnu_param_type,
                                               gnu_return_type, 0, 0, 0, 0);
                Sloc_to_locus (Sloc (gnat_param),
                               &DECL_SOURCE_LOCATION (gnu_field));
                TREE_CHAIN (gnu_field) = gnu_field_list;
                gnu_field_list = gnu_field;
                gnu_return_list = tree_cons (gnu_field, gnu_param,
                                             gnu_return_list);
              }
          }

        /* Do not compute record for out parameters if subprogram is
           stubbed since structures are incomplete for the back-end.  */
        if (gnu_field_list
            && Convention (gnat_entity) != Convention_Stubbed)
           {
            /* If all types are not complete, defer emission of debug
               information for this record types. Otherwise, we risk emitting
               debug information for a dummy type contained in the fields
               for that record.  */
            finish_record_type (gnu_return_type, nreverse (gnu_field_list),
                                false, defer_incomplete_level);

            if (defer_incomplete_level)
              {
                debug_deferred = true;
                defer_debug_level++;

                defer_debug_incomplete_list
                  = tree_cons (NULL_TREE, gnu_return_type,
                               defer_debug_incomplete_list);
              }
          }

        /* If we have a CICO list but it has only one entry, we convert
           this function into a function that simply returns that one
           object.  */
        if (list_length (gnu_return_list) == 1)
          gnu_return_type = TREE_TYPE (TREE_PURPOSE (gnu_return_list));

        if (Has_Stdcall_Convention (gnat_entity))
          {
            struct attrib *attr
              = (struct attrib *) xmalloc (sizeof (struct attrib));

            attr->next = attr_list;
            attr->type = ATTR_MACHINE_ATTRIBUTE;
            attr->name = get_identifier ("stdcall");
            attr->args = NULL_TREE;
            attr->error_point = gnat_entity;
            attr_list = attr;
          }

        /* Both lists ware built in reverse.  */
        gnu_param_list = nreverse (gnu_param_list);
        gnu_return_list = nreverse (gnu_return_list);

        gnu_type
          = create_subprog_type (gnu_return_type, gnu_param_list,
                                 gnu_return_list, returns_unconstrained,
                                 returns_by_ref,
                                 Function_Returns_With_DSP (gnat_entity),
                                 returns_by_target_ptr);

        /* A subprogram (something that doesn't return anything) shouldn't
           be considered Pure since there would be no reason for such a
           subprogram.  Note that procedures with Out (or In Out) parameters
           have already been converted into a function with a return type. */
        if (TREE_CODE (gnu_return_type) == VOID_TYPE)
          pure_flag = false;

        /* The semantics of "pure" in Ada essentially matches that of "const"
           in the back-end.  In particular, both properties are orthogonal to
           the "nothrow" property.  But this is true only if the EH circuitry
           is explicit in the internal representation of the back-end.  If we
           are to completely hide the EH circuitry from it, we need to declare
           that calls to pure Ada subprograms that can throw have side effects
           since they can trigger an "abnormal" transfer of control flow; thus
           they can be neither "const" nor "pure" in the back-end sense.  */
        gnu_type
          = build_qualified_type (gnu_type,
                                  TYPE_QUALS (gnu_type)
                                  | (Exception_Mechanism == Back_End_Exceptions
                                     ? TYPE_QUAL_CONST * pure_flag : 0)
                                  | (TYPE_QUAL_VOLATILE * volatile_flag));

        Sloc_to_locus (Sloc (gnat_entity), &input_location);

        /* If we have a builtin decl for that function, check the signatures
           compatibilities.  If the signatures are compatible, use the builtin
           decl.  If they are not, we expect the checker predicate to have
           posted the appropriate errors, and just continue with what we have
           so far.  */
        if (gnu_builtin_decl)
          {
            tree gnu_builtin_type =  TREE_TYPE (gnu_builtin_decl);

            if (compatible_signatures_p (gnu_type, gnu_builtin_type))
              {
                gnu_decl = gnu_builtin_decl;
                gnu_type = gnu_builtin_type;
                break;
              }
          }

        /* If there was no specified Interface_Name and the external and
           internal names of the subprogram are the same, only use the
           internal name to allow disambiguation of nested subprograms.  */
        if (No (Interface_Name (gnat_entity)) && gnu_ext_name == gnu_entity_id)
          gnu_ext_name = NULL_TREE;

        /* If we are defining the subprogram and it has an Address clause
           we must get the address expression from the saved GCC tree for the
           subprogram if it has a Freeze_Node.  Otherwise, we elaborate
           the address expression here since the front-end has guaranteed
           in that case that the elaboration has no effects.  If there is
           an Address clause and we are not defining the object, just
           make it a constant.  */
        if (Present (Address_Clause (gnat_entity)))
          {
            tree gnu_address = NULL_TREE;

            if (definition)
              gnu_address
                = (present_gnu_tree (gnat_entity)
                   ? get_gnu_tree (gnat_entity)
                   : gnat_to_gnu (Expression (Address_Clause (gnat_entity))));

            save_gnu_tree (gnat_entity, NULL_TREE, false);

            /* Convert the type of the object to a reference type that can
               alias everything as per 13.3(19).  */
            gnu_type
              = build_reference_type_for_mode (gnu_type, ptr_mode, true);
            if (gnu_address)
              gnu_address = convert (gnu_type, gnu_address);

            gnu_decl
              = create_var_decl (gnu_entity_id, gnu_ext_name, gnu_type,
                                 gnu_address, false, Is_Public (gnat_entity),
                                 extern_flag, false, NULL, gnat_entity);
            DECL_BY_REF_P (gnu_decl) = 1;
          }

        else if (kind == E_Subprogram_Type)
          gnu_decl = create_type_decl (gnu_entity_id, gnu_type, attr_list,
                                       !Comes_From_Source (gnat_entity),
                                       debug_info_p && !defer_incomplete_level,
                                       gnat_entity);
        else
          {
            gnu_decl = create_subprog_decl (gnu_entity_id, gnu_ext_name,
                                            gnu_type, gnu_param_list,
                                            inline_flag, public_flag,
                                            extern_flag, attr_list,
                                            gnat_entity);

            DECL_STUBBED_P (gnu_decl)
              = Convention (gnat_entity) == Convention_Stubbed;
          }
      }
      break;

    case E_Incomplete_Type:
    case E_Incomplete_Subtype:
    case E_Private_Type:
    case E_Private_Subtype:
    case E_Limited_Private_Type:
    case E_Limited_Private_Subtype:
    case E_Record_Type_With_Private:
    case E_Record_Subtype_With_Private:
      {
        /* Get the "full view" of this entity.  If this is an incomplete
           entity from a limited with, treat its non-limited view as the
           full view.  Otherwise, use either the full view or the underlying
           full view, whichever is present.  This is used in all the tests
           below.  */
        Entity_Id full_view
          = (IN (Ekind (gnat_entity), Incomplete_Kind)
             && From_With_Type (gnat_entity))
            ? Non_Limited_View (gnat_entity)
            : Present (Full_View (gnat_entity))
              ? Full_View (gnat_entity)
              : Underlying_Full_View (gnat_entity);

        /* If this is an incomplete type with no full view, it must be a Taft
           Amendment type, in which case we return a dummy type.  Otherwise,
           just get the type from its Etype.  */
        if (No (full_view))
          {
            if (kind == E_Incomplete_Type)
              gnu_type = make_dummy_type (gnat_entity);
            else
              {
                gnu_decl = gnat_to_gnu_entity (Etype (gnat_entity),
                                               NULL_TREE, 0);
                maybe_present = true;
              }
            break;
          }

        /* If we already made a type for the full view, reuse it.  */
        else if (present_gnu_tree (full_view))
          {
            gnu_decl = get_gnu_tree (full_view);
            break;
          }

        /* Otherwise, if we are not defining the type now, get the type
           from the full view.  But always get the type from the full view
           for define on use types, since otherwise we won't see them!  */
        else if (!definition
                 || (Is_Itype (full_view)
                   && No (Freeze_Node (gnat_entity)))
                 || (Is_Itype (gnat_entity)
                   && No (Freeze_Node (full_view))))
          {
            gnu_decl = gnat_to_gnu_entity (full_view, NULL_TREE, 0);
            maybe_present = true;
            break;
          }

        /* For incomplete types, make a dummy type entry which will be
           replaced later.  */
        gnu_type = make_dummy_type (gnat_entity);

        /* Save this type as the full declaration's type so we can do any
           needed updates when we see it.  */
        gnu_decl = create_type_decl (gnu_entity_id, gnu_type, attr_list,
                                     !Comes_From_Source (gnat_entity),
                                     debug_info_p, gnat_entity);
        save_gnu_tree (full_view, gnu_decl, 0);
        break;
      }

      /* Simple class_wide types are always viewed as their root_type
         by Gigi unless an Equivalent_Type is specified.  */
    case E_Class_Wide_Type:
      if (Present (Equivalent_Type (gnat_entity)))
        gnu_decl = gnat_to_gnu_entity (Equivalent_Type (gnat_entity),
                                       NULL_TREE, 0);
      else
        gnu_decl = gnat_to_gnu_entity (Root_Type (gnat_entity),
                                       NULL_TREE, 0);

      maybe_present = true;
      break;

    case E_Task_Type:
    case E_Task_Subtype:
    case E_Protected_Type:
    case E_Protected_Subtype:
      if (type_annotate_only && No (Corresponding_Record_Type (gnat_entity)))
        gnu_type = void_type_node;
      else
        gnu_type = gnat_to_gnu_type (Corresponding_Record_Type (gnat_entity));

      maybe_present = true;
      break;

    case E_Label:
      gnu_decl = create_label_decl (gnu_entity_id);
      break;

    case E_Block:
    case E_Loop:
      /* Nothing at all to do here, so just return an ERROR_MARK and claim
         we've already saved it, so we don't try to.  */
      gnu_decl = error_mark_node;
      saved = true;
      break;

    default:
      gcc_unreachable ();
    }

  /* If we had a case where we evaluated another type and it might have
     defined this one, handle it here.  */
  if (maybe_present && present_gnu_tree (gnat_entity))
    {
      gnu_decl = get_gnu_tree (gnat_entity);
      saved = true;
    }

  /* If we are processing a type and there is either no decl for it or
     we just made one, do some common processing for the type, such as
     handling alignment and possible padding.  */

  if ((!gnu_decl || this_made_decl) && IN (kind, Type_Kind))
    {
      if (Is_Tagged_Type (gnat_entity)
          || Is_Class_Wide_Equivalent_Type (gnat_entity))
        TYPE_ALIGN_OK (gnu_type) = 1;

      if (AGGREGATE_TYPE_P (gnu_type) && Is_By_Reference_Type (gnat_entity))
        TYPE_BY_REFERENCE_P (gnu_type) = 1;

      /* ??? Don't set the size for a String_Literal since it is either
         confirming or we don't handle it properly (if the low bound is
         non-constant).  */
      if (!gnu_size && kind != E_String_Literal_Subtype)
        gnu_size = validate_size (Esize (gnat_entity), gnu_type, gnat_entity,
                                  TYPE_DECL, false,
                                  Has_Size_Clause (gnat_entity));

      /* If a size was specified, see if we can make a new type of that size
         by rearranging the type, for example from a fat to a thin pointer.  */
      if (gnu_size)
        {
          gnu_type
            = make_type_from_size (gnu_type, gnu_size,
                                   Has_Biased_Representation (gnat_entity));

          if (operand_equal_p (TYPE_SIZE (gnu_type), gnu_size, 0)
              && operand_equal_p (rm_size (gnu_type), gnu_size, 0))
            gnu_size = 0;
        }

      /* If the alignment hasn't already been processed and this is
         not an unconstrained array, see if an alignment is specified.
         If not, we pick a default alignment for atomic objects.  */
      if (align != 0 || TREE_CODE (gnu_type) == UNCONSTRAINED_ARRAY_TYPE)
        ;
      else if (Known_Alignment (gnat_entity))
        align = validate_alignment (Alignment (gnat_entity), gnat_entity,
                                    TYPE_ALIGN (gnu_type));
      else if (Is_Atomic (gnat_entity) && !gnu_size
               && host_integerp (TYPE_SIZE (gnu_type), 1)
               && integer_pow2p (TYPE_SIZE (gnu_type)))
        align = MIN (BIGGEST_ALIGNMENT,
                     tree_low_cst (TYPE_SIZE (gnu_type), 1));
      else if (Is_Atomic (gnat_entity) && gnu_size
               && host_integerp (gnu_size, 1)
               && integer_pow2p (gnu_size))
        align = MIN (BIGGEST_ALIGNMENT, tree_low_cst (gnu_size, 1));

      /* See if we need to pad the type.  If we did, and made a record,
         the name of the new type may be changed.  So get it back for
         us when we make the new TYPE_DECL below.  */
      gnu_type = maybe_pad_type (gnu_type, gnu_size, align, gnat_entity, "PAD",
                                 true, definition, false);
      if (TREE_CODE (gnu_type) == RECORD_TYPE
          && TYPE_IS_PADDING_P (gnu_type))
        {
          gnu_entity_id = TYPE_NAME (gnu_type);
          if (TREE_CODE (gnu_entity_id) == TYPE_DECL)
            gnu_entity_id = DECL_NAME (gnu_entity_id);
        }

      set_rm_size (RM_Size (gnat_entity), gnu_type, gnat_entity);

      /* If we are at global level, GCC will have applied variable_size to
         the type, but that won't have done anything.  So, if it's not
         a constant or self-referential, call elaborate_expression_1 to
         make a variable for the size rather than calculating it each time.
         Handle both the RM size and the actual size.  */
      if (global_bindings_p ()
          && TYPE_SIZE (gnu_type)
          && !TREE_CONSTANT (TYPE_SIZE (gnu_type))
          && !CONTAINS_PLACEHOLDER_P (TYPE_SIZE (gnu_type)))
        {
          if (TREE_CODE (gnu_type) == RECORD_TYPE
              && operand_equal_p (TYPE_ADA_SIZE (gnu_type),
                                  TYPE_SIZE (gnu_type), 0))
            {
              TYPE_SIZE (gnu_type)
                = elaborate_expression_1 (gnat_entity, gnat_entity,
                                          TYPE_SIZE (gnu_type),
                                          get_identifier ("SIZE"),
                                          definition, 0);
              SET_TYPE_ADA_SIZE (gnu_type, TYPE_SIZE (gnu_type));
            }
          else
            {
              TYPE_SIZE (gnu_type)
                = elaborate_expression_1 (gnat_entity, gnat_entity,
                                          TYPE_SIZE (gnu_type),
                                          get_identifier ("SIZE"),
                                          definition, 0);

              /* ??? For now, store the size as a multiple of the alignment
                 in bytes so that we can see the alignment from the tree.  */
              TYPE_SIZE_UNIT (gnu_type)
                = build_binary_op
                  (MULT_EXPR, sizetype,
                   elaborate_expression_1
                   (gnat_entity, gnat_entity,
                    build_binary_op (EXACT_DIV_EXPR, sizetype,
                                     TYPE_SIZE_UNIT (gnu_type),
                                     size_int (TYPE_ALIGN (gnu_type)
                                               / BITS_PER_UNIT)),
                    get_identifier ("SIZE_A_UNIT"),
                    definition, 0),
                   size_int (TYPE_ALIGN (gnu_type) / BITS_PER_UNIT));

              if (TREE_CODE (gnu_type) == RECORD_TYPE)
                SET_TYPE_ADA_SIZE
                  (gnu_type,
                   elaborate_expression_1 (gnat_entity,
                                           gnat_entity,
                                           TYPE_ADA_SIZE (gnu_type),
                                           get_identifier ("RM_SIZE"),
                                           definition, 0));
                 }
        }

      /* If this is a record type or subtype, call elaborate_expression_1 on
         any field position.  Do this for both global and local types.
         Skip any fields that we haven't made trees for to avoid problems with
         class wide types.  */
      if (IN (kind, Record_Kind))
        for (gnat_temp = First_Entity (gnat_entity); Present (gnat_temp);
             gnat_temp = Next_Entity (gnat_temp))
          if (Ekind (gnat_temp) == E_Component && present_gnu_tree (gnat_temp))
            {
              tree gnu_field = get_gnu_tree (gnat_temp);

              /* ??? Unfortunately, GCC needs to be able to prove the
                 alignment of this offset and if it's a variable, it can't.
                 In GCC 3.4, we'll use DECL_OFFSET_ALIGN in some way, but
                 right now, we have to put in an explicit multiply and
                 divide by that value.  */
              if (!CONTAINS_PLACEHOLDER_P (DECL_FIELD_OFFSET (gnu_field)))
                {
                DECL_FIELD_OFFSET (gnu_field)
                  = build_binary_op
                    (MULT_EXPR, sizetype,
                     elaborate_expression_1
                     (gnat_temp, gnat_temp,
                      build_binary_op (EXACT_DIV_EXPR, sizetype,
                                       DECL_FIELD_OFFSET (gnu_field),
                                       size_int (DECL_OFFSET_ALIGN (gnu_field)
                                                 / BITS_PER_UNIT)),
                      get_identifier ("OFFSET"),
                      definition, 0),
                     size_int (DECL_OFFSET_ALIGN (gnu_field) / BITS_PER_UNIT));

                /* ??? The context of gnu_field is not necessarily gnu_type so
                   the MULT_EXPR node built above may not be marked by the call
                   to create_type_decl below.  Mark it manually for now.  */
                if (global_bindings_p ())
                  TREE_VISITED (DECL_FIELD_OFFSET (gnu_field)) = 1;
                }
            }

      gnu_type = build_qualified_type (gnu_type,
                                       (TYPE_QUALS (gnu_type)
                                        | (TYPE_QUAL_VOLATILE
                                           * Treat_As_Volatile (gnat_entity))));

      if (Is_Atomic (gnat_entity))
        check_ok_for_atomic (gnu_type, gnat_entity, false);

      if (Known_Alignment (gnat_entity))
        TYPE_USER_ALIGN (gnu_type) = 1;

      if (!gnu_decl)
        gnu_decl = create_type_decl (gnu_entity_id, gnu_type, attr_list,
                                     !Comes_From_Source (gnat_entity),
                                     debug_info_p, gnat_entity);
      else
        TREE_TYPE (gnu_decl) = gnu_type;
    }

  if (IN (kind, Type_Kind) && !TYPE_IS_DUMMY_P (TREE_TYPE (gnu_decl)))
    {
      gnu_type = TREE_TYPE (gnu_decl);

      /* Back-annotate the Alignment of the type if not already in the
         tree.  Likewise for sizes.  */
      if (Unknown_Alignment (gnat_entity))
        Set_Alignment (gnat_entity,
                       UI_From_Int (TYPE_ALIGN (gnu_type) / BITS_PER_UNIT));

      if (Unknown_Esize (gnat_entity) && TYPE_SIZE (gnu_type))
        {
          /* If the size is self-referential, we annotate the maximum
             value of that size.  */
          tree gnu_size = TYPE_SIZE (gnu_type);

          if (CONTAINS_PLACEHOLDER_P (gnu_size))
            gnu_size = max_size (gnu_size, true);

          Set_Esize (gnat_entity, annotate_value (gnu_size));

          if (type_annotate_only && Is_Tagged_Type (gnat_entity))
            {
              /* In this mode the tag and the parent components are not
                 generated by the front-end, so the sizes must be adjusted
                 explicitly now. */

             int size_offset;
             int new_size;

             if (Is_Derived_Type (gnat_entity))
               {
                 size_offset
                   = UI_To_Int (Esize (Etype (Base_Type (gnat_entity))));
                 Set_Alignment (gnat_entity,
                                Alignment (Etype (Base_Type (gnat_entity))));
               }
             else
               size_offset = POINTER_SIZE;

             new_size = UI_To_Int (Esize (gnat_entity)) + size_offset;
             Set_Esize (gnat_entity,
                        UI_From_Int (((new_size + (POINTER_SIZE - 1))
                                      / POINTER_SIZE) * POINTER_SIZE));
             Set_RM_Size (gnat_entity, Esize (gnat_entity));
           }
        }

      if (Unknown_RM_Size (gnat_entity) && rm_size (gnu_type))
        Set_RM_Size (gnat_entity, annotate_value (rm_size (gnu_type)));
    }

  if (!Comes_From_Source (gnat_entity) && DECL_P (gnu_decl))
    DECL_ARTIFICIAL (gnu_decl) = 1;

  if (!debug_info_p && DECL_P (gnu_decl)
      && TREE_CODE (gnu_decl) != FUNCTION_DECL
      && No (Renamed_Object (gnat_entity)))
    DECL_IGNORED_P (gnu_decl) = 1;

  /* If we haven't already, associate the ..._DECL node that we just made with
     the input GNAT entity node. */
  if (!saved)
    save_gnu_tree (gnat_entity, gnu_decl, false);

  /* If this is an enumeral or floating-point type, we were not able to set
     the bounds since they refer to the type.  These bounds are always static.

     For enumeration types, also write debugging information and declare the
     enumeration literal  table, if needed.  */

  if ((kind == E_Enumeration_Type && Present (First_Literal (gnat_entity)))
      || (kind == E_Floating_Point_Type && !Vax_Float (gnat_entity)))
    {
      tree gnu_scalar_type = gnu_type;

      /* If this is a padded type, we need to use the underlying type.  */
      if (TREE_CODE (gnu_scalar_type) == RECORD_TYPE
          && TYPE_IS_PADDING_P (gnu_scalar_type))
        gnu_scalar_type = TREE_TYPE (TYPE_FIELDS (gnu_scalar_type));

      /* If this is a floating point type and we haven't set a floating
         point type yet, use this in the evaluation of the bounds.  */
      if (!longest_float_type_node && kind == E_Floating_Point_Type)
        longest_float_type_node = gnu_type;

      TYPE_MIN_VALUE (gnu_scalar_type)
        = gnat_to_gnu (Type_Low_Bound (gnat_entity));
      TYPE_MAX_VALUE (gnu_scalar_type)
        = gnat_to_gnu (Type_High_Bound (gnat_entity));

      if (TREE_CODE (gnu_scalar_type) == ENUMERAL_TYPE)
        {
          TYPE_STUB_DECL (gnu_scalar_type) = gnu_decl;

          /* Since this has both a typedef and a tag, avoid outputting
             the name twice.  */
          DECL_ARTIFICIAL (gnu_decl) = 1;
          rest_of_type_compilation (gnu_scalar_type, global_bindings_p ());
        }
    }

  /* If we deferred processing of incomplete types, re-enable it.  If there
     were no other disables and we have some to process, do so.  */
  if (this_deferred && --defer_incomplete_level == 0 && defer_incomplete_list)
    {
      struct incomplete *incp = defer_incomplete_list;
      struct incomplete *next;

      defer_incomplete_list = NULL;
      for (; incp; incp = next)
        {
          next = incp->next;

          if (incp->old_type)
            update_pointer_to (TYPE_MAIN_VARIANT (incp->old_type),
                               gnat_to_gnu_type (incp->full_type));
          free (incp);
        }
    }

  /* If we are not defining this type, see if it's in the incomplete list.
     If so, handle that list entry now.  */
  else if (!definition)
    {
      struct incomplete *incp;

      for (incp = defer_incomplete_list; incp; incp = incp->next)
        if (incp->old_type && incp->full_type == gnat_entity)
          {
            update_pointer_to (TYPE_MAIN_VARIANT (incp->old_type),
                               TREE_TYPE (gnu_decl));
            incp->old_type = NULL_TREE;
          }
    }

   /* If there are no incomplete types and we have deferred emission
      of debug information, check whether we have finished defining
      all nested records.
      If so, handle the list now.  */

   if (debug_deferred)
     defer_debug_level--;

   if (defer_debug_incomplete_list
       && !defer_incomplete_level
       && !defer_debug_level)
    {
      tree c, n;

      defer_debug_incomplete_list = nreverse (defer_debug_incomplete_list);

      for (c = defer_debug_incomplete_list; c; c = n)
        {
          n = TREE_CHAIN (c);
          write_record_type_debug_info (TREE_VALUE (c));
        }

      defer_debug_incomplete_list = 0;
    }

  if (this_global)
    force_global--;

  if (Is_Packed_Array_Type (gnat_entity)
      && Is_Itype (Associated_Node_For_Itype (gnat_entity))
      && No (Freeze_Node (Associated_Node_For_Itype (gnat_entity)))
      && !present_gnu_tree (Associated_Node_For_Itype (gnat_entity)))
    gnat_to_gnu_entity (Associated_Node_For_Itype (gnat_entity), NULL_TREE, 0);

  return gnu_decl;
}

/* Similar, but if the returned value is a COMPONENT_REF, return the
   FIELD_DECL.  */

tree
gnat_to_gnu_field_decl (Entity_Id gnat_entity)
{
  tree gnu_field = gnat_to_gnu_entity (gnat_entity, NULL_TREE, 0);

  if (TREE_CODE (gnu_field) == COMPONENT_REF)
    gnu_field = TREE_OPERAND (gnu_field, 1);

  return gnu_field;
}

/* Return true if DISCR1 and DISCR2 represent the same discriminant.  */

static
bool same_discriminant_p (Entity_Id discr1, Entity_Id discr2)
{
  while (Present (Corresponding_Discriminant (discr1)))
    discr1 = Corresponding_Discriminant (discr1);

  while (Present (Corresponding_Discriminant (discr2)))
    discr2 = Corresponding_Discriminant (discr2);

  return
    Original_Record_Component (discr1) == Original_Record_Component (discr2);
}
\f
/* Given GNAT_ENTITY, elaborate all expressions that are required to
   be elaborated at the point of its definition, but do nothing else.  */

void
elaborate_entity (Entity_Id gnat_entity)
{
  switch (Ekind (gnat_entity))
    {
    case E_Signed_Integer_Subtype:
    case E_Modular_Integer_Subtype:
    case E_Enumeration_Subtype:
    case E_Ordinary_Fixed_Point_Subtype:
    case E_Decimal_Fixed_Point_Subtype:
    case E_Floating_Point_Subtype:
      {
        Node_Id gnat_lb = Type_Low_Bound (gnat_entity);
        Node_Id gnat_hb = Type_High_Bound (gnat_entity);

        /* ??? Tests for avoiding static constraint error expression
           is needed until the front stops generating bogus conversions
           on bounds of real types. */

        if (!Raises_Constraint_Error (gnat_lb))
          elaborate_expression (gnat_lb, gnat_entity, get_identifier ("L"),
                                1, 0, Needs_Debug_Info (gnat_entity));
        if (!Raises_Constraint_Error (gnat_hb))
          elaborate_expression (gnat_hb, gnat_entity, get_identifier ("U"),
                                1, 0, Needs_Debug_Info (gnat_entity));
      break;
      }

    case E_Record_Type:
      {
        Node_Id full_definition = Declaration_Node (gnat_entity);
        Node_Id record_definition = Type_Definition (full_definition);

        /* If this is a record extension, go a level further to find the
           record definition.  */
        if (Nkind (record_definition) == N_Derived_Type_Definition)
          record_definition = Record_Extension_Part (record_definition);
      }
      break;

    case E_Record_Subtype:
    case E_Private_Subtype:
    case E_Limited_Private_Subtype:
    case E_Record_Subtype_With_Private:
      if (Is_Constrained (gnat_entity)
          && Has_Discriminants (Base_Type (gnat_entity))
          && Present (Discriminant_Constraint (gnat_entity)))
        {
          Node_Id gnat_discriminant_expr;
          Entity_Id gnat_field;

          for (gnat_field = First_Discriminant (Base_Type (gnat_entity)),
               gnat_discriminant_expr
               = First_Elmt (Discriminant_Constraint (gnat_entity));
               Present (gnat_field);
               gnat_field = Next_Discriminant (gnat_field),
               gnat_discriminant_expr = Next_Elmt (gnat_discriminant_expr))
            /* ??? For now, ignore access discriminants.  */
            if (!Is_Access_Type (Etype (Node (gnat_discriminant_expr))))
              elaborate_expression (Node (gnat_discriminant_expr),
                                    gnat_entity,
                                    get_entity_name (gnat_field), 1, 0, 0);
        }
      break;

    }
}
\f
/* Mark GNAT_ENTITY as going out of scope at this point.  Recursively mark
   any entities on its entity chain similarly.  */

void
mark_out_of_scope (Entity_Id gnat_entity)
{
  Entity_Id gnat_sub_entity;
  unsigned int kind = Ekind (gnat_entity);

  /* If this has an entity list, process all in the list.  */
  if (IN (kind, Class_Wide_Kind) || IN (kind, Concurrent_Kind)
      || IN (kind, Private_Kind)
      || kind == E_Block || kind == E_Entry || kind == E_Entry_Family
      || kind == E_Function || kind == E_Generic_Function
      || kind == E_Generic_Package || kind == E_Generic_Procedure
      || kind == E_Loop || kind == E_Operator || kind == E_Package
      || kind == E_Package_Body || kind == E_Procedure
      || kind == E_Record_Type || kind == E_Record_Subtype
      || kind == E_Subprogram_Body || kind == E_Subprogram_Type)
    for (gnat_sub_entity = First_Entity (gnat_entity);
         Present (gnat_sub_entity);
         gnat_sub_entity = Next_Entity (gnat_sub_entity))
      if (Scope (gnat_sub_entity) == gnat_entity
          && gnat_sub_entity != gnat_entity)
        mark_out_of_scope (gnat_sub_entity);

  /* Now clear this if it has been defined, but only do so if it isn't
     a subprogram or parameter.  We could refine this, but it isn't
     worth it.  If this is statically allocated, it is supposed to
     hang around out of cope.  */
  if (present_gnu_tree (gnat_entity) && !Is_Statically_Allocated (gnat_entity)
      && kind != E_Procedure && kind != E_Function && !IN (kind, Formal_Kind))
    {
      save_gnu_tree (gnat_entity, NULL_TREE, true);
      save_gnu_tree (gnat_entity, error_mark_node, true);
    }
}
\f
/* Set the alias set of GNU_NEW_TYPE to be that of GNU_OLD_TYPE.  If this
   is a multi-dimensional array type, do this recursively.  */

static void
copy_alias_set (tree gnu_new_type, tree gnu_old_type)
{
  /* Remove any padding from GNU_OLD_TYPE.  It doesn't matter in the case
     of a one-dimensional array, since the padding has the same alias set
     as the field type, but if it's a multi-dimensional array, we need to
     see the inner types.  */
  while (TREE_CODE (gnu_old_type) == RECORD_TYPE
         && (TYPE_JUSTIFIED_MODULAR_P (gnu_old_type)
             || TYPE_IS_PADDING_P (gnu_old_type)))
    gnu_old_type = TREE_TYPE (TYPE_FIELDS (gnu_old_type));

  /* We need to be careful here in case GNU_OLD_TYPE is an unconstrained
     array.  In that case, it doesn't have the same shape as GNU_NEW_TYPE,
     so we need to go down to what does.  */
  if (TREE_CODE (gnu_old_type) == UNCONSTRAINED_ARRAY_TYPE)
    gnu_old_type
      = TREE_TYPE (TREE_TYPE (TYPE_FIELDS (TREE_TYPE (gnu_old_type))));

  if (TREE_CODE (gnu_new_type) == ARRAY_TYPE
      && TREE_CODE (TREE_TYPE (gnu_new_type)) == ARRAY_TYPE
      && TYPE_MULTI_ARRAY_P (TREE_TYPE (gnu_new_type)))
    copy_alias_set (TREE_TYPE (gnu_new_type), TREE_TYPE (gnu_old_type));

  TYPE_ALIAS_SET (gnu_new_type) = get_alias_set (gnu_old_type);
  record_component_aliases (gnu_new_type);
}
\f
/* Return a TREE_LIST describing the substitutions needed to reflect
   discriminant substitutions from GNAT_SUBTYPE to GNAT_TYPE and add
   them to GNU_LIST.  If GNAT_TYPE is not specified, use the base type
   of GNAT_SUBTYPE. The substitutions can be in any order.  TREE_PURPOSE
   gives the tree for the discriminant and TREE_VALUES is the replacement
   value.  They are in the form of operands to substitute_in_expr.
   DEFINITION is as in gnat_to_gnu_entity.  */

static tree
substitution_list (Entity_Id gnat_subtype, Entity_Id gnat_type,
                   tree gnu_list, bool definition)
{
  Entity_Id gnat_discrim;
  Node_Id gnat_value;

  if (No (gnat_type))
    gnat_type = Implementation_Base_Type (gnat_subtype);

  if (Has_Discriminants (gnat_type))
    for (gnat_discrim = First_Stored_Discriminant (gnat_type),
         gnat_value = First_Elmt (Stored_Constraint (gnat_subtype));
         Present (gnat_discrim);
         gnat_discrim = Next_Stored_Discriminant (gnat_discrim),
         gnat_value = Next_Elmt (gnat_value))
      /* Ignore access discriminants.  */
      if (!Is_Access_Type (Etype (Node (gnat_value))))
        gnu_list = tree_cons (gnat_to_gnu_field_decl (gnat_discrim),
                              elaborate_expression
                              (Node (gnat_value), gnat_subtype,
                               get_entity_name (gnat_discrim), definition,
                               1, 0),
                              gnu_list);

  return gnu_list;
}
\f
/* Return true if the size represented by GNU_SIZE can be handled by an
   allocation.  If STATIC_P is true, consider only what can be done with a
   static allocation.  */

static bool
allocatable_size_p (tree gnu_size, bool static_p)
{
  HOST_WIDE_INT our_size;

  /* If this is not a static allocation, the only case we want to forbid
     is an overflowing size.  That will be converted into a raise a
     Storage_Error.  */
  if (!static_p)
    return !(TREE_CODE (gnu_size) == INTEGER_CST
             && TREE_OVERFLOW (gnu_size));

  /* Otherwise, we need to deal with both variable sizes and constant
     sizes that won't fit in a host int.  We use int instead of HOST_WIDE_INT
     since assemblers may not like very large sizes.  */
  if (!host_integerp (gnu_size, 1))
    return false;

  our_size = tree_low_cst (gnu_size, 1);
  return (int) our_size == our_size;
}
\f
/* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any.  */

static void
prepend_attributes (Entity_Id gnat_entity, struct attrib ** attr_list)
{
  Node_Id gnat_temp;

  for (gnat_temp = First_Rep_Item (gnat_entity); Present (gnat_temp);
       gnat_temp = Next_Rep_Item (gnat_temp))
    if (Nkind (gnat_temp) == N_Pragma)
      {
        struct attrib *attr;
        tree gnu_arg0 = NULL_TREE, gnu_arg1 = NULL_TREE;
        Node_Id gnat_assoc = Pragma_Argument_Associations (gnat_temp);
        enum attr_type etype;

        if (Present (gnat_assoc) && Present (First (gnat_assoc))
            && Present (Next (First (gnat_assoc)))
            && (Nkind (Expression (Next (First (gnat_assoc))))
                == N_String_Literal))
          {
            gnu_arg0 = get_identifier (TREE_STRING_POINTER
                                       (gnat_to_gnu
                                        (Expression (Next
                                                     (First (gnat_assoc))))));
            if (Present (Next (Next (First (gnat_assoc))))
                && (Nkind (Expression (Next (Next (First (gnat_assoc)))))
                    == N_String_Literal))
              gnu_arg1 = get_identifier (TREE_STRING_POINTER
                                         (gnat_to_gnu
                                          (Expression
                                           (Next (Next
                                                  (First (gnat_assoc)))))));
          }

        switch (Get_Pragma_Id (Chars (gnat_temp)))
          {
          case Pragma_Machine_Attribute:
            etype = ATTR_MACHINE_ATTRIBUTE;
            break;

          case Pragma_Linker_Alias:
            etype = ATTR_LINK_ALIAS;
            break;

          case Pragma_Linker_Section:
            etype = ATTR_LINK_SECTION;
            break;

          case Pragma_Linker_Constructor:
            etype = ATTR_LINK_CONSTRUCTOR;
            break;

          case Pragma_Linker_Destructor:
            etype = ATTR_LINK_DESTRUCTOR;
            break;

          case Pragma_Weak_External:
            etype = ATTR_WEAK_EXTERNAL;
            break;

          default:
            continue;
          }

        attr = (struct attrib *) xmalloc (sizeof (struct attrib));
        attr->next = *attr_list;
        attr->type = etype;
        attr->name = gnu_arg0;

        /* If we have an argument specified together with an attribute name,
           make it a single TREE_VALUE entry in a list of arguments, as GCC
           expects it.  */
        if (gnu_arg1 != NULL_TREE)
          attr->args = build_tree_list (NULL_TREE, gnu_arg1);
        else
          attr->args = NULL_TREE;

        attr->error_point
          = Present (Next (First (gnat_assoc)))
            ? Expression (Next (First (gnat_assoc))) : gnat_temp;
        *attr_list = attr;
      }
}
\f
/* Get the unpadded version of a GNAT type.  */

tree
get_unpadded_type (Entity_Id gnat_entity)
{
  tree type = gnat_to_gnu_type (gnat_entity);

  if (TREE_CODE (type) == RECORD_TYPE && TYPE_IS_PADDING_P (type))
    type = TREE_TYPE (TYPE_FIELDS (type));

  return type;
}
\f
/* Called when we need to protect a variable object using a save_expr.  */

tree
maybe_variable (tree gnu_operand)
{
  if (TREE_CONSTANT (gnu_operand) || TREE_READONLY (gnu_operand)
      || TREE_CODE (gnu_operand) == SAVE_EXPR
      || TREE_CODE (gnu_operand) == NULL_EXPR)
    return gnu_operand;

  if (TREE_CODE (gnu_operand) == UNCONSTRAINED_ARRAY_REF)
    {
      tree gnu_result = build1 (UNCONSTRAINED_ARRAY_REF,
                                TREE_TYPE (gnu_operand),
                                variable_size (TREE_OPERAND (gnu_operand, 0)));

      TREE_READONLY (gnu_result) = TREE_STATIC (gnu_result)
        = TYPE_READONLY (TREE_TYPE (TREE_TYPE (gnu_operand)));
      return gnu_result;
    }
  else
    return variable_size (gnu_operand);
}
\f
/* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
   type definition (either a bound or a discriminant value) for GNAT_ENTITY,
   return the GCC tree to use for that expression.  GNU_NAME is the
   qualification to use if an external name is appropriate and DEFINITION is
   nonzero if this is a definition of GNAT_ENTITY.  If NEED_VALUE is nonzero,
   we need a result.  Otherwise, we are just elaborating this for
   side-effects.  If NEED_DEBUG is nonzero we need the symbol for debugging
   purposes even if it isn't needed for code generation.  */

static tree
elaborate_expression (Node_Id gnat_expr, Entity_Id gnat_entity,
                      tree gnu_name, bool definition, bool need_value,
                      bool need_debug)
{
  tree gnu_expr;

  /* If we already elaborated this expression (e.g., it was involved
     in the definition of a private type), use the old value.  */
  if (present_gnu_tree (gnat_expr))
    return get_gnu_tree (gnat_expr);

  /* If we don't need a value and this is static or a discriminant, we
     don't need to do anything.  */
  else if (!need_value
           && (Is_OK_Static_Expression (gnat_expr)
               || (Nkind (gnat_expr) == N_Identifier
                   && Ekind (Entity (gnat_expr)) == E_Discriminant)))
    return 0;

  /* Otherwise, convert this tree to its GCC equivalent.  */
  gnu_expr
    = elaborate_expression_1 (gnat_expr, gnat_entity, gnat_to_gnu (gnat_expr),
                              gnu_name, definition, need_debug);

  /* Save the expression in case we try to elaborate this entity again.  Since
     this is not a DECL, don't check it.  Don't save if it's a discriminant. */
  if (!CONTAINS_PLACEHOLDER_P (gnu_expr))
    save_gnu_tree (gnat_expr, gnu_expr, true);

  return need_value ? gnu_expr : error_mark_node;
}

/* Similar, but take a GNU expression.  */

static tree
elaborate_expression_1 (Node_Id gnat_expr, Entity_Id gnat_entity,
                        tree gnu_expr, tree gnu_name, bool definition,
                        bool need_debug)
{
  tree gnu_decl = NULL_TREE;
  /* Strip any conversions to see if the expression is a readonly variable.
     ??? This really should remain readonly, but we have to think about
     the typing of the tree here.  */
  tree gnu_inner_expr = remove_conversions (gnu_expr, true);
  bool expr_global = Is_Public (gnat_entity) || global_bindings_p ();
  bool expr_variable;

  /* In most cases, we won't see a naked FIELD_DECL here because a
     discriminant reference will have been replaced with a COMPONENT_REF
     when the type is being elaborated.  However, there are some cases
     involving child types where we will.  So convert it to a COMPONENT_REF
     here.  We have to hope it will be at the highest level of the
     expression in these cases.  */
  if (TREE_CODE (gnu_expr) == FIELD_DECL)
    gnu_expr = build3 (COMPONENT_REF, TREE_TYPE (gnu_expr),
                       build0 (PLACEHOLDER_EXPR, DECL_CONTEXT (gnu_expr)),
                       gnu_expr, NULL_TREE);

  /* If GNU_EXPR is neither a placeholder nor a constant, nor a variable
     that is a constant, make a variable that is initialized to contain the
     bound when the package containing the definition is elaborated.  If
     this entity is defined at top level and a bound or discriminant value
     isn't a constant or a reference to a discriminant, replace the bound
     by the variable; otherwise use a SAVE_EXPR if needed.  Note that we
     rely here on the fact that an expression cannot contain both the
     discriminant and some other variable.  */

  expr_variable = (!CONSTANT_CLASS_P (gnu_expr)
                   && !(TREE_CODE (gnu_inner_expr) == VAR_DECL
                        && (TREE_READONLY (gnu_inner_expr)
                            || DECL_READONLY_ONCE_ELAB (gnu_inner_expr)))
                   && !CONTAINS_PLACEHOLDER_P (gnu_expr));

  /* If this is a static expression or contains a discriminant, we don't
     need the variable for debugging (and can't elaborate anyway if a
     discriminant).  */
  if (need_debug
      && (Is_OK_Static_Expression (gnat_expr)
          || CONTAINS_PLACEHOLDER_P (gnu_expr)))
    need_debug = false;

  /* Now create the variable if we need it.  */
  if (need_debug || (expr_variable && expr_global))
    gnu_decl
      = create_var_decl (create_concat_name (gnat_entity,
                                             IDENTIFIER_POINTER (gnu_name)),
                         NULL_TREE, TREE_TYPE (gnu_expr), gnu_expr,
                         !need_debug, Is_Public (gnat_entity),
                         !definition, false, NULL, gnat_entity);

  /* We only need to use this variable if we are in global context since GCC
     can do the right thing in the local case.  */
  if (expr_global && expr_variable)
    return gnu_decl;
  else if (!expr_variable)
    return gnu_expr;
  else
    return maybe_variable (gnu_expr);
}
\f
/* Create a record type that contains a field of TYPE with a starting bit
   position so that it is aligned to ALIGN bits and is SIZE bytes long.  */

tree
make_aligning_type (tree type, int align, tree size)
{
  tree record_type = make_node (RECORD_TYPE);
  tree place = build0 (PLACEHOLDER_EXPR, record_type);
  tree size_addr_place = convert (sizetype,
                                  build_unary_op (ADDR_EXPR, NULL_TREE,
                                                  place));
  tree name = TYPE_NAME (type);
  tree pos, field;

  if (TREE_CODE (name) == TYPE_DECL)
    name = DECL_NAME (name);

  TYPE_NAME (record_type) = concat_id_with_name (name, "_ALIGN");

  /* The bit position is obtained by "and"ing the alignment minus 1
     with the two's complement of the address and  multiplying
     by the number of bits per unit.  Do all this in sizetype.  */
  pos = size_binop (MULT_EXPR,
                    convert (bitsizetype,
                             size_binop (BIT_AND_EXPR,
                                         size_diffop (size_zero_node,
                                                      size_addr_place),
                                         ssize_int ((align / BITS_PER_UNIT)
                                                    - 1))),
                    bitsize_unit_node);

  /* Create the field, with -1 as the 'addressable' indication to avoid the
     creation of a bitfield.  We don't need one, it would have damaging
     consequences on the alignment computation, and create_field_decl would
     make one without this special argument, for instance because of the
     complex position expression.  */
  field = create_field_decl (get_identifier ("F"), type, record_type, 1, size,
                             pos, -1);

  finish_record_type (record_type, field, true, false);
  TYPE_ALIGN (record_type) = BIGGEST_ALIGNMENT;
  TYPE_SIZE (record_type)
    = size_binop (PLUS_EXPR,
                  size_binop (MULT_EXPR, convert (bitsizetype, size),
                              bitsize_unit_node),
                  bitsize_int (align));
  TYPE_SIZE_UNIT (record_type)
    = size_binop (PLUS_EXPR, size, size_int (align / BITS_PER_UNIT));
  copy_alias_set (record_type, type);
  return record_type;
}
\f
/* TYPE is a RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE, with BLKmode that's
   being used as the field type of a packed record.  See if we can rewrite it
   as a record that has a non-BLKmode type, which we can pack tighter.  If so,
   return the new type.  If not, return the original type.  */

static tree
make_packable_type (tree type)
{
  tree new_type = make_node (TREE_CODE (type));
  tree field_list = NULL_TREE;
  tree old_field;

  /* Copy the name and flags from the old type to that of the new and set
     the alignment to try for an integral type.  For QUAL_UNION_TYPE,
     also copy the size.  */
  TYPE_NAME (new_type) = TYPE_NAME (type);
  TYPE_JUSTIFIED_MODULAR_P (new_type)
    = TYPE_JUSTIFIED_MODULAR_P (type);
  TYPE_CONTAINS_TEMPLATE_P (new_type) = TYPE_CONTAINS_TEMPLATE_P (type);

  if (TREE_CODE (type) == RECORD_TYPE)
    TYPE_IS_PADDING_P (new_type) = TYPE_IS_PADDING_P (type);
  else if (TREE_CODE (type) == QUAL_UNION_TYPE)
    {
      TYPE_SIZE (new_type) = TYPE_SIZE (type);
      TYPE_SIZE_UNIT (new_type) = TYPE_SIZE_UNIT (type);
    }

  TYPE_ALIGN (new_type)
    = ((HOST_WIDE_INT) 1
       << (floor_log2 (tree_low_cst (TYPE_SIZE (type), 1) - 1) + 1));

  /* Now copy the fields, keeping the position and size.  */
  for (old_field = TYPE_FIELDS (type); old_field;
       old_field = TREE_CHAIN (old_field))
    {
      tree new_field_type = TREE_TYPE (old_field);
      tree new_field;

      if (TYPE_MODE (new_field_type) == BLKmode
          && (TREE_CODE (new_field_type) == RECORD_TYPE
              || TREE_CODE (new_field_type) == UNION_TYPE
              || TREE_CODE (new_field_type) == QUAL_UNION_TYPE)
          && host_integerp (TYPE_SIZE (new_field_type), 1))
        new_field_type = make_packable_type (new_field_type);

      new_field = create_field_decl (DECL_NAME (old_field), new_field_type,
                                     new_type, TYPE_PACKED (type),
                                     DECL_SIZE (old_field),
                                     bit_position (old_field),
                                     !DECL_NONADDRESSABLE_P (old_field));

      DECL_INTERNAL_P (new_field) = DECL_INTERNAL_P (old_field);
      SET_DECL_ORIGINAL_FIELD
        (new_field, (DECL_ORIGINAL_FIELD (old_field)
                     ? DECL_ORIGINAL_FIELD (old_field) : old_field));

      if (TREE_CODE (new_type) == QUAL_UNION_TYPE)
        DECL_QUALIFIER (new_field) = DECL_QUALIFIER (old_field);

      TREE_CHAIN (new_field) = field_list;
      field_list = new_field;
    }

  finish_record_type (new_type, nreverse (field_list), true, true);
  copy_alias_set (new_type, type);
  return TYPE_MODE (new_type) == BLKmode ? type : new_type;
}
\f
/* Ensure that TYPE has SIZE and ALIGN.  Make and return a new padded type
   if needed.  We have already verified that SIZE and TYPE are large enough.

   GNAT_ENTITY and NAME_TRAILER are used to name the resulting record and
   to issue a warning.

   IS_USER_TYPE is true if we must be sure we complete the original type.

   DEFINITION is true if this type is being defined.

   SAME_RM_SIZE is true if the RM_Size of the resulting type is to be
   set to its TYPE_SIZE; otherwise, it's set to the RM_Size of the original
   type.  */

tree
maybe_pad_type (tree type, tree size, unsigned int align,
                Entity_Id gnat_entity, const char *name_trailer,
                bool is_user_type, bool definition, bool same_rm_size)
{
  tree orig_size = TYPE_SIZE (type);
  tree record;
  tree field;

  /* If TYPE is a padded type, see if it agrees with any size and alignment
     we were given.  If so, return the original type.  Otherwise, strip
     off the padding, since we will either be returning the inner type
     or repadding it.  If no size or alignment is specified, use that of
     the original padded type.  */

  if (TREE_CODE (type) == RECORD_TYPE && TYPE_IS_PADDING_P (type))
    {
      if ((!size
           || operand_equal_p (round_up (size,
                                         MAX (align, TYPE_ALIGN (type))),
                               round_up (TYPE_SIZE (type),
                                         MAX (align, TYPE_ALIGN (type))),
                               0))
          && (align == 0 || align == TYPE_ALIGN (type)))
        return type;

      if (!size)
        size = TYPE_SIZE (type);
      if (align == 0)
        align = TYPE_ALIGN (type);

      type = TREE_TYPE (TYPE_FIELDS (type));
      orig_size = TYPE_SIZE (type);
    }

  /* If the size is either not being changed or is being made smaller (which
     is not done here (and is only valid for bitfields anyway), show the size
     isn't changing.  Likewise, clear the alignment if it isn't being
     changed.  Then return if we aren't doing anything.  */

  if (size
      && (operand_equal_p (size, orig_size, 0)
          || (TREE_CODE (orig_size) == INTEGER_CST
              && tree_int_cst_lt (size, orig_size))))
    size = NULL_TREE;

  if (align == TYPE_ALIGN (type))
    align = 0;

  if (align == 0 && !size)
    return type;

  /* We used to modify the record in place in some cases, but that could
     generate incorrect debugging information.  So make a new record
     type and name.  */
  record = make_node (RECORD_TYPE);

  if (Present (gnat_entity))
    TYPE_NAME (record) = create_concat_name (gnat_entity, name_trailer);

  /* If we were making a type, complete the original type and give it a
     name.  */
  if (is_user_type)
    create_type_decl (get_entity_name (gnat_entity), type,
                      NULL, !Comes_From_Source (gnat_entity),
                      !(TYPE_NAME (type)
                        && TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
                        && DECL_IGNORED_P (TYPE_NAME (type))),
                      gnat_entity);

  /* If we are changing the alignment and the input type is a record with
     BLKmode and a small constant size, try to make a form that has an
     integral mode.  That might allow this record to have an integral mode,
     which will be much more efficient.  There is no point in doing this if a
     size is specified unless it is also smaller than the biggest alignment
     and it is incorrect to do this if the size of the original type is not a
     multiple of the alignment.  */
  if (align != 0
      && TREE_CODE (type) == RECORD_TYPE
      && TYPE_MODE (type) == BLKmode
      && host_integerp (orig_size, 1)
      && compare_tree_int (orig_size, BIGGEST_ALIGNMENT) <= 0
      && (!size
          || (TREE_CODE (size) == INTEGER_CST
              && compare_tree_int (size, BIGGEST_ALIGNMENT) <= 0))
      && tree_low_cst (orig_size, 1) % align == 0)
    type = make_packable_type (type);

  field  = create_field_decl (get_identifier ("F"), type, record, 0,
                              NULL_TREE, bitsize_zero_node, 1);

  DECL_INTERNAL_P (field) = 1;
  TYPE_SIZE (record) = size ? size : orig_size;
  TYPE_SIZE_UNIT (record)
    = (size ? convert (sizetype,
                       size_binop (CEIL_DIV_EXPR, size, bitsize_unit_node))
       : TYPE_SIZE_UNIT (type));

  TYPE_ALIGN (record) = align;
  TYPE_IS_PADDING_P (record) = 1;
  TYPE_VOLATILE (record)
    = Present (gnat_entity) && Treat_As_Volatile (gnat_entity);
  finish_record_type (record, field, true, false);

  /* Keep the RM_Size of the padded record as that of the old record
     if requested.  */
  SET_TYPE_ADA_SIZE (record, same_rm_size ? size : rm_size (type));

  /* Unless debugging information isn't being written for the input type,
     write a record that shows what we are a subtype of and also make a
     variable that indicates our size, if variable. */
  if (TYPE_NAME (record) && AGGREGATE_TYPE_P (type)
      && (TREE_CODE (TYPE_NAME (type)) != TYPE_DECL
          || !DECL_IGNORED_P (TYPE_NAME (type))))
    {
      tree marker = make_node (RECORD_TYPE);
      tree name = (TREE_CODE (TYPE_NAME (record)) == TYPE_DECL
                   ? DECL_NAME (TYPE_NAME (record))
                   : TYPE_NAME (record));
      tree orig_name = TYPE_NAME (type);

      if (TREE_CODE (orig_name) == TYPE_DECL)
        orig_name = DECL_NAME (orig_name);

      TYPE_NAME (marker) = concat_id_with_name (name, "XVS");
      finish_record_type (marker,
                          create_field_decl (orig_name, integer_type_node,
                                             marker, 0, NULL_TREE, NULL_TREE,
                                             0),
                          false, false);

      if (size && TREE_CODE (size) != INTEGER_CST && definition)
        create_var_decl (concat_id_with_name (name, "XVZ"), NULL_TREE,
                         bitsizetype, TYPE_SIZE (record), false, false, false,
                         false, NULL, gnat_entity);
    }

  type = record;

  if (CONTAINS_PLACEHOLDER_P (orig_size))
    orig_size = max_size (orig_size, true);

  /* If the size was widened explicitly, maybe give a warning.  */
  if (size && Present (gnat_entity)
      && !operand_equal_p (size, orig_size, 0)
      && !(TREE_CODE (size) == INTEGER_CST
           && TREE_CODE (orig_size) == INTEGER_CST
           && tree_int_cst_lt (size, orig_size)))
    {
      Node_Id gnat_error_node = Empty;

      if (Is_Packed_Array_Type (gnat_entity))
        gnat_entity = Associated_Node_For_Itype (gnat_entity);

      if ((Ekind (gnat_entity) == E_Component
           || Ekind (gnat_entity) == E_Discriminant)
          && Present (Component_Clause (gnat_entity)))
        gnat_error_node = Last_Bit (Component_Clause (gnat_entity));
      else if (Present (Size_Clause (gnat_entity)))
        gnat_error_node = Expression (Size_Clause (gnat_entity));

      /* Generate message only for entities that come from source, since
         if we have an entity created by expansion, the message will be
         generated for some other corresponding source entity.  */
      if (Comes_From_Source (gnat_entity) && Present (gnat_error_node))
        post_error_ne_tree ("{^ }bits of & unused?", gnat_error_node,
                            gnat_entity,
                            size_diffop (size, orig_size));

      else if (*name_trailer == 'C' && !Is_Internal (gnat_entity))
        post_error_ne_tree ("component of& padded{ by ^ bits}?",
                            gnat_entity, gnat_entity,
                            size_diffop (size, orig_size));
    }

  return type;
}
\f
/* Given a GNU tree and a GNAT list of choices, generate an expression to test
   the value passed against the list of choices.  */

tree
choices_to_gnu (tree operand, Node_Id choices)
{
  Node_Id choice;
  Node_Id gnat_temp;
  tree result = integer_zero_node;
  tree this_test, low = 0, high = 0, single = 0;

  for (choice = First (choices); Present (choice); choice = Next (choice))
    {
      switch (Nkind (choice))
        {
        case N_Range:
          low = gnat_to_gnu (Low_Bound (choice));
          high = gnat_to_gnu (High_Bound (choice));

          /* There's no good type to use here, so we might as well use
             integer_type_node.  */
          this_test
            = build_binary_op (TRUTH_ANDIF_EXPR, integer_type_node,
                               build_binary_op (GE_EXPR, integer_type_node,
                                                operand, low),
                               build_binary_op (LE_EXPR, integer_type_node,
                                                operand, high));

          break;

        case N_Subtype_Indication:
          gnat_temp = Range_Expression (Constraint (choice));
          low = gnat_to_gnu (Low_Bound (gnat_temp));
          high = gnat_to_gnu (High_Bound (gnat_temp));

          this_test
            = build_binary_op (TRUTH_ANDIF_EXPR, integer_type_node,
                               build_binary_op (GE_EXPR, integer_type_node,
                                                operand, low),
                               build_binary_op (LE_EXPR, integer_type_node,
                                                operand, high));
          break;

        case N_Identifier:
        case N_Expanded_Name:
          /* This represents either a subtype range, an enumeration
             literal, or a constant  Ekind says which.  If an enumeration
             literal or constant, fall through to the next case.  */
          if (Ekind (Entity (choice)) != E_Enumeration_Literal
              && Ekind (Entity (choice)) != E_Constant)
            {
              tree type = gnat_to_gnu_type (Entity (choice));

              low = TYPE_MIN_VALUE (type);
              high = TYPE_MAX_VALUE (type);

              this_test
                = build_binary_op (TRUTH_ANDIF_EXPR, integer_type_node,
                                   build_binary_op (GE_EXPR, integer_type_node,
                                                    operand, low),
                                   build_binary_op (LE_EXPR, integer_type_node,
                                                    operand, high));
              break;
            }
          /* ... fall through ... */
        case N_Character_Literal:
        case N_Integer_Literal:
          single = gnat_to_gnu (choice);
          this_test = build_binary_op (EQ_EXPR, integer_type_node, operand,
                                       single);
          break;

        case N_Others_Choice:
          this_test = integer_one_node;
          break;

        default:
          gcc_unreachable ();
        }

      result = build_binary_op (TRUTH_ORIF_EXPR, integer_type_node,
                                result, this_test);
    }

  return result;
}
\f
/* Return a GCC tree for a field corresponding to GNAT_FIELD to be
   placed in GNU_RECORD_TYPE.

   PACKED is 1 if the enclosing record is packed and -1 if the enclosing
   record has a Component_Alignment of Storage_Unit.

   DEFINITION is true if this field is for a record being defined.  */

static tree
gnat_to_gnu_field (Entity_Id gnat_field, tree gnu_record_type, int packed,
                   bool definition)
{
  tree gnu_field_id = get_entity_name (gnat_field);
  tree gnu_field_type = gnat_to_gnu_type (Etype (gnat_field));
  tree gnu_pos = 0;
  tree gnu_size = 0;
  tree gnu_field;
  bool needs_strict_alignment
    = (Is_Aliased (gnat_field) || Strict_Alignment (Etype (gnat_field))
       || Treat_As_Volatile (gnat_field));

  /* If this field requires strict alignment or contains an item of
     variable sized, pretend it isn't packed.  */
  if (needs_strict_alignment || is_variable_size (gnu_field_type))
    packed = 0;

  /* For packed records, this is one of the few occasions on which we use
     the official RM size for discrete or fixed-point components, instead
     of the normal GNAT size stored in Esize. See description in Einfo:
     "Handling of Type'Size Values" for further details.  */

  if (packed == 1)
    gnu_size = validate_size (RM_Size (Etype (gnat_field)), gnu_field_type,
                              gnat_field, FIELD_DECL, false, true);

  if (Known_Static_Esize (gnat_field))
    gnu_size = validate_size (Esize (gnat_field), gnu_field_type,
                              gnat_field, FIELD_DECL, false, true);

  /* If we have a specified size that's smaller than that of the field type,
     or a position is specified, and the field type is also a record that's
     BLKmode and with a small constant size, see if we can get an integral
     mode form of the type when appropriate.  If we can, show a size was
     specified for the field if there wasn't one already, so we know to make
     this a bitfield and avoid making things wider.

     Doing this is first useful if the record is packed because we can then
     place the field at a non-byte-aligned position and so achieve tighter
     packing.

     This is in addition *required* if the field shares a byte with another
     field and the front-end lets the back-end handle the references, because
     GCC does not handle BLKmode bitfields properly.

     We avoid the transformation if it is not required or potentially useful,
     as it might entail an increase of the field's alignment and have ripple
     effects on the outer record type.  A typical case is a field known to be
     byte aligned and not to share a byte with another field.

     Besides, we don't even look the possibility of a transformation in cases
     known to be in error already, for instance when an invalid size results
     from a component clause.  */

  if (TREE_CODE (gnu_field_type) == RECORD_TYPE
      && TYPE_MODE (gnu_field_type) == BLKmode
      && host_integerp (TYPE_SIZE (gnu_field_type), 1)
      && compare_tree_int (TYPE_SIZE (gnu_field_type), BIGGEST_ALIGNMENT) <= 0
      && (packed == 1
          || (gnu_size
              && tree_int_cst_lt (gnu_size, TYPE_SIZE (gnu_field_type)))
          || (Present (Component_Clause (gnat_field)) && gnu_size != 0)))
    {
      /* See what the alternate type and size would be.  */
      tree gnu_packable_type = make_packable_type (gnu_field_type);

      bool has_byte_aligned_clause
        = Present (Component_Clause (gnat_field))
          && (UI_To_Int (Component_Bit_Offset (gnat_field))
              % BITS_PER_UNIT == 0);

      /* Compute whether we should avoid the substitution.  */
      int reject =
        /* There is no point substituting if there is no change.  */
        (gnu_packable_type == gnu_field_type
         ||
         /* ... nor when the field is known to be byte aligned and not to
            share a byte with another field.  */
         (has_byte_aligned_clause
          && value_factor_p (gnu_size, BITS_PER_UNIT))
         ||
         /* The size of an aliased field must be an exact multiple of the
            type's alignment, which the substitution might increase.  Reject
            substitutions that would so invalidate a component clause when the
            specified position is byte aligned, as the change would have no
            real benefit from the packing standpoint anyway.  */
         (Is_Aliased (gnat_field)
          && has_byte_aligned_clause
          && ! value_factor_p (gnu_size, TYPE_ALIGN (gnu_packable_type)))
         );

      /* Substitute unless told otherwise.  */
      if (!reject)
        {
          gnu_field_type = gnu_packable_type;

          if (gnu_size == 0)
            gnu_size = rm_size (gnu_field_type);
        }
    }

  /* If we are packing the record and the field is BLKmode, round the
     size up to a byte boundary.  */
  if (packed && TYPE_MODE (gnu_field_type) == BLKmode && gnu_size)
    gnu_size = round_up (gnu_size, BITS_PER_UNIT);

  if (Present (Component_Clause (gnat_field)))
    {
      gnu_pos = UI_To_gnu (Component_Bit_Offset (gnat_field), bitsizetype);
      gnu_size = validate_size (Esize (gnat_field), gnu_field_type,
                                gnat_field, FIELD_DECL, false, true);

      /* Ensure the position does not overlap with the parent subtype,
         if there is one.  */
      if (Present (Parent_Subtype (Underlying_Type (Scope (gnat_field)))))
        {
          tree gnu_parent
            = gnat_to_gnu_type (Parent_Subtype
                                (Underlying_Type (Scope (gnat_field))));

          if (TREE_CODE (TYPE_SIZE (gnu_parent)) == INTEGER_CST
              && tree_int_cst_lt (gnu_pos, TYPE_SIZE (gnu_parent)))
            {
              post_error_ne_tree
                ("offset of& must be beyond parent{, minimum allowed is ^}",
                 First_Bit (Component_Clause (gnat_field)), gnat_field,
                 TYPE_SIZE_UNIT (gnu_parent));
            }
        }

      /* If this field needs strict alignment, ensure the record is
         sufficiently aligned and that that position and size are
         consistent with the alignment.  */
      if (needs_strict_alignment)
        {
          tree gnu_rounded_size = round_up (rm_size (gnu_field_type),
                                            TYPE_ALIGN (gnu_field_type));

          TYPE_ALIGN (gnu_record_type)
            = MAX (TYPE_ALIGN (gnu_record_type), TYPE_ALIGN (gnu_field_type));

          /* If Atomic, the size must match exactly that of the field.  */
          if ((Is_Atomic (gnat_field) || Is_Atomic (Etype (gnat_field)))
              && !operand_equal_p (gnu_size, TYPE_SIZE (gnu_field_type), 0))
            {
              post_error_ne_tree
                ("atomic field& must be natural size of type{ (^)}",
                 Last_Bit (Component_Clause (gnat_field)), gnat_field,
                 TYPE_SIZE (gnu_field_type));

              gnu_size = NULL_TREE;
            }

          /* If Aliased, the size must match exactly the rounded size.  We
             used to be more accommodating here and accept greater sizes, but
             fully supporting this case on big-endian platforms would require
             switching to a more involved layout for the field.  */
          else if (Is_Aliased (gnat_field)
                   && gnu_size
                   && ! operand_equal_p (gnu_size, gnu_rounded_size, 0))
            {
              post_error_ne_tree
                ("size of aliased field& must be ^ bits",
                 Last_Bit (Component_Clause (gnat_field)), gnat_field,
                 gnu_rounded_size);
              gnu_size = NULL_TREE;
            }

          if (!integer_zerop (size_binop
                              (TRUNC_MOD_EXPR, gnu_pos,
                               bitsize_int (TYPE_ALIGN (gnu_field_type)))))
            {
              if (Is_Aliased (gnat_field))
                post_error_ne_num
                  ("position of aliased field& must be multiple of ^ bits",
                   First_Bit (Component_Clause (gnat_field)), gnat_field,
                   TYPE_ALIGN (gnu_field_type));

              else if (Treat_As_Volatile (gnat_field))
                post_error_ne_num
                  ("position of volatile field& must be multiple of ^ bits",
                   First_Bit (Component_Clause (gnat_field)), gnat_field,
                   TYPE_ALIGN (gnu_field_type));

              else if (Strict_Alignment (Etype (gnat_field)))
                post_error_ne_num
  ("position of & with aliased or tagged components not multiple of ^ bits",
                   First_Bit (Component_Clause (gnat_field)), gnat_field,
                   TYPE_ALIGN (gnu_field_type));
              else
                gcc_unreachable ();

              gnu_pos = NULL_TREE;
            }
        }

      if (Is_Atomic (gnat_field))
        check_ok_for_atomic (gnu_field_type, gnat_field, false);
    }

  /* If the record has rep clauses and this is the tag field, make a rep
     clause for it as well.  */
  else if (Has_Specified_Layout (Scope (gnat_field))
           && Chars (gnat_field) == Name_uTag)
    {
      gnu_pos = bitsize_zero_node;
      gnu_size = TYPE_SIZE (gnu_field_type);
    }

  /* We need to make the size the maximum for the type if it is
     self-referential and an unconstrained type.  In that case, we can't
     pack the field since we can't make a copy to align it.  */
  if (TREE_CODE (gnu_field_type) == RECORD_TYPE
      && !gnu_size
      && CONTAINS_PLACEHOLDER_P (TYPE_SIZE (gnu_field_type))
      && !Is_Constrained (Underlying_Type (Etype (gnat_field))))
    {
      gnu_size = max_size (TYPE_SIZE (gnu_field_type), true);
      packed = 0;
    }

  /* If no size is specified (or if there was an error), don't specify a
     position.  */
  if (!gnu_size)
    gnu_pos = NULL_TREE;
  else
    {
      /* If the field's type is justified modular, we would need to remove
         the wrapper to (better) meet the layout requirements.  However we
         can do so only if the field is not aliased to preserve the unique
         layout and if the prescribed size is not greater than that of the
         packed array to preserve the justification.  */
      if (!needs_strict_alignment
          && TREE_CODE (gnu_field_type) == RECORD_TYPE
          && TYPE_JUSTIFIED_MODULAR_P (gnu_field_type)
          && tree_int_cst_compare (gnu_size, TYPE_ADA_SIZE (gnu_field_type))
               <= 0)
        gnu_field_type = TREE_TYPE (TYPE_FIELDS (gnu_field_type));

      gnu_field_type
        = make_type_from_size (gnu_field_type, gnu_size,
                               Has_Biased_Representation (gnat_field));
      gnu_field_type = maybe_pad_type (gnu_field_type, gnu_size, 0, gnat_field,
                                       "PAD", false, definition, true);
    }

  gcc_assert (TREE_CODE (gnu_field_type) != RECORD_TYPE
              || !TYPE_CONTAINS_TEMPLATE_P (gnu_field_type));

  /* Now create the decl for the field.  */
  gnu_field = create_field_decl (gnu_field_id, gnu_field_type, gnu_record_type,
                                 packed, gnu_size, gnu_pos,
                                 Is_Aliased (gnat_field));
  Sloc_to_locus (Sloc (gnat_field), &DECL_SOURCE_LOCATION (gnu_field));
  TREE_THIS_VOLATILE (gnu_field) = Treat_As_Volatile (gnat_field);

  if (Ekind (gnat_field) == E_Discriminant)
    DECL_DISCRIMINANT_NUMBER (gnu_field)
      = UI_To_gnu (Discriminant_Number (gnat_field), sizetype);

  return gnu_field;
}
\f
/* Return true if TYPE is a type with variable size, a padding type with a
   field of variable size or is a record that has a field such a field.  */

static bool
is_variable_size (tree type)
{
  tree field;

  /* We need not be concerned about this at all if we don't have
     strict alignment.  */
  if (!STRICT_ALIGNMENT)
    return false;
  else if (!TREE_CONSTANT (TYPE_SIZE (type)))
    return true;
  else if (TREE_CODE (type) == RECORD_TYPE && TYPE_IS_PADDING_P (type)
           && !TREE_CONSTANT (DECL_SIZE (TYPE_FIELDS (type))))
    return true;
  else if (TREE_CODE (type) != RECORD_TYPE
           && TREE_CODE (type) != UNION_TYPE
           && TREE_CODE (type) != QUAL_UNION_TYPE)
    return false;

  for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
    if (is_variable_size (TREE_TYPE (field)))
      return true;

  return false;
}
\f
/* Return a GCC tree for a record type given a GNAT Component_List and a chain
   of GCC trees for fields that are in the record and have already been
   processed.  When called from gnat_to_gnu_entity during the processing of a
   record type definition, the GCC nodes for the discriminants will be on
   the chain.  The other calls to this function are recursive calls from
   itself for the Component_List of a variant and the chain is empty.

   PACKED is 1 if this is for a record with "pragma pack" and -1 is this is
   for a record type with "pragma component_alignment (storage_unit)".

   DEFINITION is true if we are defining this record.

   P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
   with a rep clause is to be added.  If it is nonzero, that is all that
   should be done with such fields.

   CANCEL_ALIGNMENT, if true, means the alignment should be zeroed before
   laying out the record.  This means the alignment only serves to force fields
   to be bitfields, but not require the record to be that aligned.  This is
   used for variants.

   ALL_REP, if true, means a rep clause was found for all the fields.  This
   simplifies the logic since we know we're not in the mixed case.

   DEFER_DEBUG, if true, means that the debugging routines should not be
   called when finishing constructing the record type.

   UNCHECKED_UNION, if tree, means that we are building a type for a record
   with a Pragma Unchecked_Union.

   The processing of the component list fills in the chain with all of the
   fields of the record and then the record type is finished.  */

static void
components_to_record (tree gnu_record_type, Node_Id component_list,
                      tree gnu_field_list, int packed, bool definition,
                      tree *p_gnu_rep_list, bool cancel_alignment,
                      bool all_rep, bool defer_debug, bool unchecked_union)
{
  Node_Id component_decl;
  Entity_Id gnat_field;
  Node_Id variant_part;
  tree gnu_our_rep_list = NULL_TREE;
  tree gnu_field, gnu_last;
  bool layout_with_rep = false;
  bool all_rep_and_size = all_rep && TYPE_SIZE (gnu_record_type);

  /* For each variable within each component declaration create a GCC field
     and add it to the list, skipping any pragmas in the list.  */

  if (Present (Component_Items (component_list)))
    for (component_decl = First_Non_Pragma (Component_Items (component_list));
         Present (component_decl);
         component_decl = Next_Non_Pragma (component_decl))
      {
        gnat_field = Defining_Entity (component_decl);

        if (Chars (gnat_field) == Name_uParent)
          gnu_field = tree_last (TYPE_FIELDS (gnu_record_type));
        else
          {
            gnu_field = gnat_to_gnu_field (gnat_field, gnu_record_type,
                                           packed, definition);

            /* If this is the _Tag field, put it before any discriminants,
               instead of after them as is the case for all other fields.
               Ignore field of void type if only annotating.  */
            if (Chars (gnat_field) == Name_uTag)
              gnu_field_list = chainon (gnu_field_list, gnu_field);
            else
              {
                TREE_CHAIN (gnu_field) = gnu_field_list;
                gnu_field_list = gnu_field;
              }
          }

          save_gnu_tree (gnat_field, gnu_field, false);
        }

  /* At the end of the component list there may be a variant part.  */
  variant_part = Variant_Part (component_list);

  /* We create a QUAL_UNION_TYPE for the variant part since the variants are
     mutually exclusive and should go in the same memory.  To do this we need
     to treat each variant as a record whose elements are created from the
     component list for the variant.  So here we create the records from the
     lists for the variants and put them all into the QUAL_UNION_TYPE.
     If this is an Unchecked_Union, we make a UNION_TYPE instead or
     use GNU_RECORD_TYPE if there are no fields so far.  */
  if (Present (variant_part))
    {
      tree gnu_discriminant = gnat_to_gnu (Name (variant_part));
      Node_Id variant;
      tree gnu_name = TYPE_NAME (gnu_record_type);
      tree gnu_var_name
        = concat_id_with_name (get_identifier (Get_Name_String
                                               (Chars (Name (variant_part)))),
                               "XVN");
      tree gnu_union_type;
      tree gnu_union_name;
      tree gnu_union_field;
      tree gnu_variant_list = NULL_TREE;

      if (TREE_CODE (gnu_name) == TYPE_DECL)
        gnu_name = DECL_NAME (gnu_name);

      gnu_union_name = concat_id_with_name (gnu_name,
                                            IDENTIFIER_POINTER (gnu_var_name));

      if (!gnu_field_list && TREE_CODE (gnu_record_type) == UNION_TYPE)
        gnu_union_type = gnu_record_type;
      else
        {

          gnu_union_type
            = make_node (unchecked_union ? UNION_TYPE : QUAL_UNION_TYPE);

          TYPE_NAME (gnu_union_type) = gnu_union_name;
          TYPE_PACKED (gnu_union_type) = TYPE_PACKED (gnu_record_type);
        }

      for (variant = First_Non_Pragma (Variants (variant_part));
           Present (variant);
           variant = Next_Non_Pragma (variant))
        {
          tree gnu_variant_type = make_node (RECORD_TYPE);
          tree gnu_inner_name;
          tree gnu_qual;

          Get_Variant_Encoding (variant);
          gnu_inner_name = get_identifier (Name_Buffer);
          TYPE_NAME (gnu_variant_type)
            = concat_id_with_name (gnu_union_name,
                                   IDENTIFIER_POINTER (gnu_inner_name));

          /* Set the alignment of the inner type in case we need to make
             inner objects into bitfields, but then clear it out
             so the record actually gets only the alignment required.  */
          TYPE_ALIGN (gnu_variant_type) = TYPE_ALIGN (gnu_record_type);
          TYPE_PACKED (gnu_variant_type) = TYPE_PACKED (gnu_record_type);

          /* Similarly, if the outer record has a size specified and all fields
             have record rep clauses, we can propagate the size into the
             variant part.  */
          if (all_rep_and_size)
            {
              TYPE_SIZE (gnu_variant_type) = TYPE_SIZE (gnu_record_type);
              TYPE_SIZE_UNIT (gnu_variant_type)
                = TYPE_SIZE_UNIT (gnu_record_type);
            }

          /* Create the record for the variant.  Note that we defer emitting
             debug info for it until after we are sure to actually use it.  */
          components_to_record (gnu_variant_type, Component_List (variant),
                                NULL_TREE, packed, definition,
                                &gnu_our_rep_list, !all_rep_and_size, all_rep,
                                true, unchecked_union);

          gnu_qual = choices_to_gnu (gnu_discriminant,
                                     Discrete_Choices (variant));

          Set_Present_Expr (variant, annotate_value (gnu_qual));

          /* If this is an Unchecked_Union and we have exactly one field,
             use that field here.  */
          if (unchecked_union && TYPE_FIELDS (gnu_variant_type)
              && !TREE_CHAIN (TYPE_FIELDS (gnu_variant_type)))
            gnu_field = TYPE_FIELDS (gnu_variant_type);
          else
            {
              /* Emit debug info for the record.  We used to throw away
                 empty records but we no longer do that because we need
                 them to generate complete debug info for the variant;
                 otherwise, the union type definition will be lacking
                 the fields associated with these empty variants.  */
              write_record_type_debug_info (gnu_variant_type);

              gnu_field = create_field_decl (gnu_inner_name, gnu_variant_type,
                                             gnu_union_type, 0,
                                             (all_rep_and_size
                                              ? TYPE_SIZE (gnu_record_type)
                                              : 0),
                                             (all_rep_and_size
                                              ? bitsize_zero_node : 0),
                                             0);

              DECL_INTERNAL_P (gnu_field) = 1;

              if (!unchecked_union)
                DECL_QUALIFIER (gnu_field) = gnu_qual;
            }

          TREE_CHAIN (gnu_field) = gnu_variant_list;
          gnu_variant_list = gnu_field;
        }

      /* Only make the QUAL_UNION_TYPE if there are any non-empty variants.  */
      if (gnu_variant_list)
        {
          if (all_rep_and_size)
            {
              TYPE_SIZE (gnu_union_type) = TYPE_SIZE (gnu_record_type);
              TYPE_SIZE_UNIT (gnu_union_type)
                = TYPE_SIZE_UNIT (gnu_record_type);
            }

          finish_record_type (gnu_union_type, nreverse (gnu_variant_list),
                              all_rep_and_size, false);

          /* If GNU_UNION_TYPE is our record type, it means we must have an
             Unchecked_Union with no fields.  Verify that and, if so, just
             return.  */
          if (gnu_union_type == gnu_record_type)
            {
              gcc_assert (!gnu_field_list && unchecked_union);
              return;
            }

          gnu_union_field
            = create_field_decl (gnu_var_name, gnu_union_type, gnu_record_type,
                                 packed,
                                 all_rep ? TYPE_SIZE (gnu_union_type) : 0,
                                 all_rep ? bitsize_zero_node : 0, 0);

          DECL_INTERNAL_P (gnu_union_field) = 1;
          TREE_CHAIN (gnu_union_field) = gnu_field_list;
          gnu_field_list = gnu_union_field;
        }
    }

  /* Scan GNU_FIELD_LIST and see if any fields have rep clauses.  If they
     do, pull them out and put them into GNU_OUR_REP_LIST.  We have to do this
     in a separate pass since we want to handle the discriminants but can't
     play with them until we've used them in debugging data above.

     ??? Note: if we then reorder them, debugging information will be wrong,
     but there's nothing that can be done about this at the moment.  */

  for (gnu_field = gnu_field_list, gnu_last = NULL_TREE; gnu_field; )
    {
      if (DECL_FIELD_OFFSET (gnu_field))
        {
          tree gnu_next = TREE_CHAIN (gnu_field);

          if (!gnu_last)
            gnu_field_list = gnu_next;
          else
            TREE_CHAIN (gnu_last) = gnu_next;

          TREE_CHAIN (gnu_field) = gnu_our_rep_list;
          gnu_our_rep_list = gnu_field;
          gnu_field = gnu_next;
        }
      else
        {
          gnu_last = gnu_field;
          gnu_field = TREE_CHAIN (gnu_field);
        }
    }

  /* If we have any items in our rep'ed field list, it is not the case that all
     the fields in the record have rep clauses, and P_REP_LIST is nonzero,
     set it and ignore the items.  */
  if (gnu_our_rep_list && p_gnu_rep_list && !all_rep)
    *p_gnu_rep_list = chainon (*p_gnu_rep_list, gnu_our_rep_list);
  else if (gnu_our_rep_list)
    {
      /* Otherwise, sort the fields by bit position and put them into their
         own record if we have any fields without rep clauses. */
      tree gnu_rep_type
        = (gnu_field_list ? make_node (RECORD_TYPE) : gnu_record_type);
      int len = list_length (gnu_our_rep_list);
      tree *gnu_arr = (tree *) alloca (sizeof (tree) * len);
      int i;

      for (i = 0, gnu_field = gnu_our_rep_list; gnu_field;
           gnu_field = TREE_CHAIN (gnu_field), i++)
        gnu_arr[i] = gnu_field;

      qsort (gnu_arr, len, sizeof (tree), compare_field_bitpos);

      /* Put the fields in the list in order of increasing position, which
         means we start from the end.  */
      gnu_our_rep_list = NULL_TREE;
      for (i = len - 1; i >= 0; i--)
        {
          TREE_CHAIN (gnu_arr[i]) = gnu_our_rep_list;
          gnu_our_rep_list = gnu_arr[i];
          DECL_CONTEXT (gnu_arr[i]) = gnu_rep_type;
        }

      if (gnu_field_list)
        {
          finish_record_type (gnu_rep_type, gnu_our_rep_list, true, false);
          gnu_field = create_field_decl (get_identifier ("REP"), gnu_rep_type,
                                         gnu_record_type, 0, 0, 0, 1);
          DECL_INTERNAL_P (gnu_field) = 1;
          gnu_field_list = chainon (gnu_field_list, gnu_field);
        }
      else
        {
          layout_with_rep = true;
          gnu_field_list = nreverse (gnu_our_rep_list);
        }
    }

  if (cancel_alignment)
    TYPE_ALIGN (gnu_record_type) = 0;

  finish_record_type (gnu_record_type, nreverse (gnu_field_list),
                      layout_with_rep, defer_debug);
}
\f
/* Called via qsort from the above.  Returns -1, 1, depending on the
   bit positions and ordinals of the two fields.  Use DECL_UID to ensure
   a stable sort.  */

static int
compare_field_bitpos (const PTR rt1, const PTR rt2)
{
  tree *t1 = (tree *) rt1;
  tree *t2 = (tree *) rt2;

  if (tree_int_cst_equal (bit_position (*t1), bit_position (*t2)))
    return DECL_UID (*t1) < DECL_UID (*t2) ? -1 : 1;
  else if (tree_int_cst_lt (bit_position (*t1), bit_position (*t2)))
    return -1;
  else
    return 1;
}
\f
/* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
   placed into an Esize, Component_Bit_Offset, or Component_Size value
   in the GNAT tree.  */

static Uint
annotate_value (tree gnu_size)
{
  int len = TREE_CODE_LENGTH (TREE_CODE (gnu_size));
  TCode tcode;
  Node_Ref_Or_Val ops[3], ret;
  int i;
  int size;
  struct tree_int_map **h = NULL;

  /* See if we've already saved the value for this node.  */
  if (EXPR_P (gnu_size))
    {
      struct tree_int_map in;
      if (!annotate_value_cache)
        annotate_value_cache = htab_create_ggc (512, tree_int_map_hash,
                                                tree_int_map_eq, 0);
      in.base.from = gnu_size;
      h = (struct tree_int_map **)
            htab_find_slot (annotate_value_cache, &in, INSERT);

      if (*h)
        return (Node_Ref_Or_Val) (*h)->to;
    }

  /* If we do not return inside this switch, TCODE will be set to the
     code to use for a Create_Node operand and LEN (set above) will be
     the number of recursive calls for us to make.  */

  switch (TREE_CODE (gnu_size))
    {
    case INTEGER_CST:
      if (TREE_OVERFLOW (gnu_size))
        return No_Uint;

      /* This may have come from a conversion from some smaller type,
         so ensure this is in bitsizetype.  */
      gnu_size = convert (bitsizetype, gnu_size);

      /* For negative values, use NEGATE_EXPR of the supplied value.  */
      if (tree_int_cst_sgn (gnu_size) < 0)
        {
          /* The ridiculous code below is to handle the case of the largest
             negative integer.  */
          tree negative_size = size_diffop (bitsize_zero_node, gnu_size);
          bool adjust = false;
          tree temp;

          if (TREE_OVERFLOW (negative_size))
            {
              negative_size
                = size_binop (MINUS_EXPR, bitsize_zero_node,
                              size_binop (PLUS_EXPR, gnu_size,
                                          bitsize_one_node));
              adjust = true;
            }

          temp = build1 (NEGATE_EXPR, bitsizetype, negative_size);
          if (adjust)
            temp = build2 (MINUS_EXPR, bitsizetype, temp, bitsize_one_node);

          return annotate_value (temp);
        }

      if (!host_integerp (gnu_size, 1))
        return No_Uint;

      size = tree_low_cst (gnu_size, 1);

      /* This peculiar test is to make sure that the size fits in an int
         on machines where HOST_WIDE_INT is not "int".  */
      if (tree_low_cst (gnu_size, 1) == size)
        return UI_From_Int (size);
      else
        return No_Uint;

    case COMPONENT_REF:
      /* The only case we handle here is a simple discriminant reference.  */
      if (TREE_CODE (TREE_OPERAND (gnu_size, 0)) == PLACEHOLDER_EXPR
          && TREE_CODE (TREE_OPERAND (gnu_size, 1)) == FIELD_DECL
          && DECL_DISCRIMINANT_NUMBER (TREE_OPERAND (gnu_size, 1)))
        return Create_Node (Discrim_Val,
                            annotate_value (DECL_DISCRIMINANT_NUMBER
                                            (TREE_OPERAND (gnu_size, 1))),
                            No_Uint, No_Uint);
      else
        return No_Uint;

    case NOP_EXPR:  case CONVERT_EXPR:   case NON_LVALUE_EXPR:
      return annotate_value (TREE_OPERAND (gnu_size, 0));

      /* Now just list the operations we handle.  */
    case COND_EXPR:             tcode = Cond_Expr; break;
    case PLUS_EXPR:             tcode = Plus_Expr; break;
    case MINUS_EXPR:            tcode = Minus_Expr; break;
    case MULT_EXPR:             tcode = Mult_Expr; break;
    case TRUNC_DIV_EXPR:        tcode = Trunc_Div_Expr; break;
    case CEIL_DIV_EXPR:         tcode = Ceil_Div_Expr; break;
    case FLOOR_DIV_EXPR:        tcode = Floor_Div_Expr; break;
    case TRUNC_MOD_EXPR:        tcode = Trunc_Mod_Expr; break;
    case CEIL_MOD_EXPR:         tcode = Ceil_Mod_Expr; break;
    case FLOOR_MOD_EXPR:        tcode = Floor_Mod_Expr; break;
    case EXACT_DIV_EXPR:        tcode = Exact_Div_Expr; break;
    case NEGATE_EXPR:           tcode = Negate_Expr; break;
    case MIN_EXPR:              tcode = Min_Expr; break;
    case MAX_EXPR:              tcode = Max_Expr; break;
    case ABS_EXPR:              tcode = Abs_Expr; break;
    case TRUTH_ANDIF_EXPR:      tcode = Truth_Andif_Expr; break;
    case TRUTH_ORIF_EXPR:       tcode = Truth_Orif_Expr; break;
    case TRUTH_AND_EXPR:        tcode = Truth_And_Expr; break;
    case TRUTH_OR_EXPR:         tcode = Truth_Or_Expr; break;
    case TRUTH_XOR_EXPR:        tcode = Truth_Xor_Expr; break;
    case TRUTH_NOT_EXPR:        tcode = Truth_Not_Expr; break;
    case BIT_AND_EXPR:          tcode = Bit_And_Expr; break;
    case LT_EXPR:               tcode = Lt_Expr; break;
    case LE_EXPR:               tcode = Le_Expr; break;
    case GT_EXPR:               tcode = Gt_Expr; break;
    case GE_EXPR:               tcode = Ge_Expr; break;
    case EQ_EXPR:               tcode = Eq_Expr; break;
    case NE_EXPR:               tcode = Ne_Expr; break;

    default:
      return No_Uint;
    }

  /* Now get each of the operands that's relevant for this code.  If any
     cannot be expressed as a repinfo node, say we can't.  */
  for (i = 0; i < 3; i++)
    ops[i] = No_Uint;

  for (i = 0; i < len; i++)
    {
      ops[i] = annotate_value (TREE_OPERAND (gnu_size, i));
      if (ops[i] == No_Uint)
        return No_Uint;
    }

  ret = Create_Node (tcode, ops[0], ops[1], ops[2]);

  /* Save the result in the cache.  */
  if (h)
    {
      *h = ggc_alloc (sizeof (struct tree_int_map));
      (*h)->base.from = gnu_size;
      (*h)->to = ret;
    }

  return ret;
}

/* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding
   GCC type, set Component_Bit_Offset and Esize to the position and size
   used by Gigi.  */

static void
annotate_rep (Entity_Id gnat_entity, tree gnu_type)
{
  tree gnu_list;
  tree gnu_entry;
  Entity_Id gnat_field;

  /* We operate by first making a list of all fields and their positions
     (we can get the sizes easily at any time) by a recursive call
     and then update all the sizes into the tree.  */
  gnu_list = compute_field_positions (gnu_type, NULL_TREE,
                                      size_zero_node, bitsize_zero_node,
                                      BIGGEST_ALIGNMENT);

  for (gnat_field = First_Entity (gnat_entity); Present (gnat_field);
       gnat_field = Next_Entity (gnat_field))
    if ((Ekind (gnat_field) == E_Component
         || (Ekind (gnat_field) == E_Discriminant
             && !Is_Unchecked_Union (Scope (gnat_field)))))
      {
        tree parent_offset = bitsize_zero_node;

        gnu_entry = purpose_member (gnat_to_gnu_field_decl (gnat_field),
                                    gnu_list);

        if (gnu_entry)
          {
            if (type_annotate_only && Is_Tagged_Type (gnat_entity))
              {
                /* In this mode the tag and parent components have not been
                   generated, so we add the appropriate offset to each
                   component.  For a component appearing in the current
                   extension, the offset is the size of the parent.  */
            if (Is_Derived_Type (gnat_entity)
                && Original_Record_Component (gnat_field) == gnat_field)
              parent_offset
                = UI_To_gnu (Esize (Etype (Base_Type (gnat_entity))),
                             bitsizetype);
            else
              parent_offset = bitsize_int (POINTER_SIZE);
          }

          Set_Component_Bit_Offset
            (gnat_field,
             annotate_value
             (size_binop (PLUS_EXPR,
                          bit_from_pos (TREE_PURPOSE (TREE_VALUE (gnu_entry)),
                                        TREE_VALUE (TREE_VALUE
                                                    (TREE_VALUE (gnu_entry)))),
                          parent_offset)));

            Set_Esize (gnat_field,
                       annotate_value (DECL_SIZE (TREE_PURPOSE (gnu_entry))));
          }
        else if (Is_Tagged_Type (gnat_entity)
                 && Is_Derived_Type (gnat_entity))
          {
            /* If there is no gnu_entry, this is an inherited component whose
               position is the same as in the parent type.  */
            Set_Component_Bit_Offset
              (gnat_field,
               Component_Bit_Offset (Original_Record_Component (gnat_field)));
            Set_Esize (gnat_field,
                       Esize (Original_Record_Component (gnat_field)));
          }
      }
}

/* Scan all fields in GNU_TYPE and build entries where TREE_PURPOSE is the
   FIELD_DECL and TREE_VALUE a TREE_LIST with TREE_PURPOSE being the byte
   position and TREE_VALUE being a TREE_LIST with TREE_PURPOSE the value to be
   placed into DECL_OFFSET_ALIGN and TREE_VALUE the bit position.  GNU_POS is
   to be added to the position, GNU_BITPOS to the bit position, OFFSET_ALIGN is
   the present value of DECL_OFFSET_ALIGN and GNU_LIST is a list of the entries
   so far.  */

static tree
compute_field_positions (tree gnu_type, tree gnu_list, tree gnu_pos,
                         tree gnu_bitpos, unsigned int offset_align)
{
  tree gnu_field;
  tree gnu_result = gnu_list;

  for (gnu_field = TYPE_FIELDS (gnu_type); gnu_field;
       gnu_field = TREE_CHAIN (gnu_field))
    {
      tree gnu_our_bitpos = size_binop (PLUS_EXPR, gnu_bitpos,
                                        DECL_FIELD_BIT_OFFSET (gnu_field));
      tree gnu_our_offset = size_binop (PLUS_EXPR, gnu_pos,
                                        DECL_FIELD_OFFSET (gnu_field));
      unsigned int our_offset_align
        = MIN (offset_align, DECL_OFFSET_ALIGN (gnu_field));

      gnu_result
        = tree_cons (gnu_field,
                     tree_cons (gnu_our_offset,
                                tree_cons (size_int (our_offset_align),
                                           gnu_our_bitpos, NULL_TREE),
                                NULL_TREE),
                     gnu_result);

      if (DECL_INTERNAL_P (gnu_field))
        gnu_result
          = compute_field_positions (TREE_TYPE (gnu_field), gnu_result,
                                     gnu_our_offset, gnu_our_bitpos,
                                     our_offset_align);
    }

  return gnu_result;
}
\f
/* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
   corresponding to GNAT_OBJECT.  If size is valid, return a tree corresponding
   to its value.  Otherwise return 0.  KIND is VAR_DECL is we are specifying
   the size for an object, TYPE_DECL for the size of a type, and FIELD_DECL
   for the size of a field.  COMPONENT_P is true if we are being called
   to process the Component_Size of GNAT_OBJECT.  This is used for error
   message handling and to indicate to use the object size of GNU_TYPE.
   ZERO_OK is true if a size of zero is permitted; if ZERO_OK is false,
   it means that a size of zero should be treated as an unspecified size.  */

static tree
validate_size (Uint uint_size, tree gnu_type, Entity_Id gnat_object,
               enum tree_code kind, bool component_p, bool zero_ok)
{
  Node_Id gnat_error_node;
  tree type_size
    = kind == VAR_DECL ? TYPE_SIZE (gnu_type) : rm_size (gnu_type);
  tree size;

  /* Find the node to use for errors.  */
  if ((Ekind (gnat_object) == E_Component
       || Ekind (gnat_object) == E_Discriminant)
      && Present (Component_Clause (gnat_object)))
    gnat_error_node = Last_Bit (Component_Clause (gnat_object));
  else if (Present (Size_Clause (gnat_object)))
    gnat_error_node = Expression (Size_Clause (gnat_object));
  else
    gnat_error_node = gnat_object;

  /* Return 0 if no size was specified, either because Esize was not Present or
     the specified size was zero.  */
  if (No (uint_size) || uint_size == No_Uint)
    return NULL_TREE;

  /* Get the size as a tree.  Give an error if a size was specified, but cannot
     be represented as in sizetype. */
  size = UI_To_gnu (uint_size, bitsizetype);
  if (TREE_OVERFLOW (size))
    {
      post_error_ne (component_p ? "component size of & is too large"
                     : "size of & is too large",
                     gnat_error_node, gnat_object);
      return NULL_TREE;
    }

  /* Ignore a negative size since that corresponds to our back-annotation.
     Also ignore a zero size unless a size clause exists.  */
  else if (tree_int_cst_sgn (size) < 0 || (integer_zerop (size) && !zero_ok))
    return NULL_TREE;

  /* The size of objects is always a multiple of a byte.  */
  if (kind == VAR_DECL
      && !integer_zerop (size_binop (TRUNC_MOD_EXPR, size, bitsize_unit_node)))
    {
      if (component_p)
        post_error_ne ("component size for& is not a multiple of Storage_Unit",
                       gnat_error_node, gnat_object);
      else
        post_error_ne ("size for& is not a multiple of Storage_Unit",
                       gnat_error_node, gnat_object);
      return NULL_TREE;
    }

  /* If this is an integral type or a packed array type, the front-end has
     verified the size, so we need not do it here (which would entail
     checking against the bounds).  However, if this is an aliased object, it
     may not be smaller than the type of the object.  */
  if ((INTEGRAL_TYPE_P (gnu_type) || TYPE_IS_PACKED_ARRAY_TYPE_P (gnu_type))
      && !(kind == VAR_DECL && Is_Aliased (gnat_object)))
    return size;

  /* If the object is a record that contains a template, add the size of
     the template to the specified size.  */
  if (TREE_CODE (gnu_type) == RECORD_TYPE
      && TYPE_CONTAINS_TEMPLATE_P (gnu_type))
    size = size_binop (PLUS_EXPR, DECL_SIZE (TYPE_FIELDS (gnu_type)), size);

  /* Modify the size of the type to be that of the maximum size if it has a
     discriminant or the size of a thin pointer if this is a fat pointer.  */
  if (type_size && CONTAINS_PLACEHOLDER_P (type_size))
    type_size = max_size (type_size, true);
  else if (TYPE_FAT_POINTER_P (gnu_type))
    type_size = bitsize_int (POINTER_SIZE);

  /* If this is an access type, the minimum size is that given by the smallest
     integral mode that's valid for pointers.  */
  if (TREE_CODE (gnu_type) == POINTER_TYPE)
    {
      enum machine_mode p_mode;

      for (p_mode = GET_CLASS_NARROWEST_MODE (MODE_INT);
           !targetm.valid_pointer_mode (p_mode);
           p_mode = GET_MODE_WIDER_MODE (p_mode))
        ;

      type_size = bitsize_int (GET_MODE_BITSIZE (p_mode));
    }

  /* If the size of the object is a constant, the new size must not be
     smaller.  */
  if (TREE_CODE (type_size) != INTEGER_CST
      || TREE_OVERFLOW (type_size)
      || tree_int_cst_lt (size, type_size))
    {
      if (component_p)
        post_error_ne_tree
          ("component size for& too small{, minimum allowed is ^}",
           gnat_error_node, gnat_object, type_size);
      else
        post_error_ne_tree ("size for& too small{, minimum allowed is ^}",
                            gnat_error_node, gnat_object, type_size);

      if (kind == VAR_DECL && !component_p
          && TREE_CODE (rm_size (gnu_type)) == INTEGER_CST
          && !tree_int_cst_lt (size, rm_size (gnu_type)))
        post_error_ne_tree_2
          ("\\size of ^ is not a multiple of alignment (^ bits)",
           gnat_error_node, gnat_object, rm_size (gnu_type),
           TYPE_ALIGN (gnu_type));

      else if (INTEGRAL_TYPE_P (gnu_type))
        post_error_ne ("\\size would be legal if & were not aliased!",
                       gnat_error_node, gnat_object);

      return NULL_TREE;
    }

  return size;
}
\f
/* Similarly, but both validate and process a value of RM_Size.  This
   routine is only called for types.  */

static void
set_rm_size (Uint uint_size, tree gnu_type, Entity_Id gnat_entity)
{
  /* Only give an error if a Value_Size clause was explicitly given.
     Otherwise, we'd be duplicating an error on the Size clause.  */
  Node_Id gnat_attr_node
    = Get_Attribute_Definition_Clause (gnat_entity, Attr_Value_Size);
  tree old_size = rm_size (gnu_type);
  tree size;

  /* Get the size as a tree.  Do nothing if none was specified, either
     because RM_Size was not Present or if the specified size was zero.
     Give an error if a size was specified, but cannot be represented as
     in sizetype.  */
  if (No (uint_size) || uint_size == No_Uint)
    return;

  size = UI_To_gnu (uint_size, bitsizetype);
  if (TREE_OVERFLOW (size))
    {
      if (Present (gnat_attr_node))
        post_error_ne ("Value_Size of & is too large", gnat_attr_node,
                       gnat_entity);

      return;
    }

  /* Ignore a negative size since that corresponds to our back-annotation.
     Also ignore a zero size unless a size clause exists, a Value_Size
     clause exists, or this is an integer type, in which case the
     front end will have always set it.  */
  else if (tree_int_cst_sgn (size) < 0
           || (integer_zerop (size) && No (gnat_attr_node)
               && !Has_Size_Clause (gnat_entity)
               && !Is_Discrete_Or_Fixed_Point_Type (gnat_entity)))
    return;

  /* If the old size is self-referential, get the maximum size.  */
  if (CONTAINS_PLACEHOLDER_P (old_size))
    old_size = max_size (old_size, true);

  /* If the size of the object is a constant, the new size must not be
     smaller (the front end checks this for scalar types).  */
  if (TREE_CODE (old_size) != INTEGER_CST
      || TREE_OVERFLOW (old_size)
      || (AGGREGATE_TYPE_P (gnu_type)
          && tree_int_cst_lt (size, old_size)))
    {
      if (Present (gnat_attr_node))
        post_error_ne_tree
          ("Value_Size for& too small{, minimum allowed is ^}",
           gnat_attr_node, gnat_entity, old_size);

      return;
    }

  /* Otherwise, set the RM_Size.  */
  if (TREE_CODE (gnu_type) == INTEGER_TYPE
      && Is_Discrete_Or_Fixed_Point_Type (gnat_entity))
    TYPE_RM_SIZE_NUM (gnu_type) = size;
  else if (TREE_CODE (gnu_type) == ENUMERAL_TYPE)
    TYPE_RM_SIZE_NUM (gnu_type) = size;
  else if ((TREE_CODE (gnu_type) == RECORD_TYPE
            || TREE_CODE (gnu_type) == UNION_TYPE
            || TREE_CODE (gnu_type) == QUAL_UNION_TYPE)
           && !TYPE_IS_FAT_POINTER_P (gnu_type))
    SET_TYPE_ADA_SIZE (gnu_type, size);
}
\f
/* Given a type TYPE, return a new type whose size is appropriate for SIZE.
   If TYPE is the best type, return it.  Otherwise, make a new type.  We
   only support new integral and pointer types.  BIASED_P is nonzero if
   we are making a biased type.  */

static tree
make_type_from_size (tree type, tree size_tree, bool biased_p)
{
  tree new_type;
  unsigned HOST_WIDE_INT size;
  bool unsigned_p;

  /* If size indicates an error, just return TYPE to avoid propagating the
     error.  Likewise if it's too large to represent.  */
  if (!size_tree || !host_integerp (size_tree, 1))
    return type;

  size = tree_low_cst (size_tree, 1);
  switch (TREE_CODE (type))
    {
    case INTEGER_TYPE:
    case ENUMERAL_TYPE:
      /* Only do something if the type is not already the proper size and is
         not a packed array type.  */
      if (TYPE_PACKED_ARRAY_TYPE_P (type)
          || (TYPE_PRECISION (type) == size
              && biased_p == (TREE_CODE (type) == INTEGER_CST
                              && TYPE_BIASED_REPRESENTATION_P (type))))
        break;

      biased_p |= (TREE_CODE (type) == INTEGER_TYPE
                   && TYPE_BIASED_REPRESENTATION_P (type));
      unsigned_p = TYPE_UNSIGNED (type) || biased_p;

      size = MIN (size, LONG_LONG_TYPE_SIZE);
      new_type
        = unsigned_p ? make_unsigned_type (size) : make_signed_type (size);
      TREE_TYPE (new_type) = TREE_TYPE (type) ? TREE_TYPE (type) : type;
      TYPE_MIN_VALUE (new_type)
        = convert (TREE_TYPE (new_type), TYPE_MIN_VALUE (type));
      TYPE_MAX_VALUE (new_type)
        = convert (TREE_TYPE (new_type), TYPE_MAX_VALUE (type));
      TYPE_BIASED_REPRESENTATION_P (new_type) = biased_p;
      TYPE_RM_SIZE_NUM (new_type) = bitsize_int (size);
      return new_type;

    case RECORD_TYPE:
      /* Do something if this is a fat pointer, in which case we
         may need to return the thin pointer.  */
      if (TYPE_IS_FAT_POINTER_P (type) && size < POINTER_SIZE * 2)
        return
          build_pointer_type
            (TYPE_OBJECT_RECORD_TYPE (TYPE_UNCONSTRAINED_ARRAY (type)));
      break;

    case POINTER_TYPE:
      /* Only do something if this is a thin pointer, in which case we
         may need to return the fat pointer.  */
      if (TYPE_THIN_POINTER_P (type) && size >= POINTER_SIZE * 2)
        return
          build_pointer_type (TYPE_UNCONSTRAINED_ARRAY (TREE_TYPE (type)));

      break;

    default:
      break;
    }

  return type;
}
\f
/* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
   a type or object whose present alignment is ALIGN.  If this alignment is
   valid, return it.  Otherwise, give an error and return ALIGN.  */

static unsigned int
validate_alignment (Uint alignment, Entity_Id gnat_entity, unsigned int align)
{
  Node_Id gnat_error_node = gnat_entity;
  unsigned int new_align;

#ifndef MAX_OFILE_ALIGNMENT
#define MAX_OFILE_ALIGNMENT BIGGEST_ALIGNMENT
#endif

  if (Present (Alignment_Clause (gnat_entity)))
    gnat_error_node = Expression (Alignment_Clause (gnat_entity));

  /* Don't worry about checking alignment if alignment was not specified
     by the source program and we already posted an error for this entity.  */

  if (Error_Posted (gnat_entity) && !Has_Alignment_Clause (gnat_entity))
    return align;

  /* Within GCC, an alignment is an integer, so we must make sure a
     value is specified that fits in that range.  Also, alignments of
     more than MAX_OFILE_ALIGNMENT can't be supported.  */

  if (! UI_Is_In_Int_Range (alignment)
      || ((new_align = UI_To_Int (alignment))
           > MAX_OFILE_ALIGNMENT / BITS_PER_UNIT))
    post_error_ne_num ("largest supported alignment for& is ^",
                       gnat_error_node, gnat_entity,
                       MAX_OFILE_ALIGNMENT / BITS_PER_UNIT);
  else if (!(Present (Alignment_Clause (gnat_entity))
             && From_At_Mod (Alignment_Clause (gnat_entity)))
           && new_align * BITS_PER_UNIT < align)
    post_error_ne_num ("alignment for& must be at least ^",
                       gnat_error_node, gnat_entity,
                       align / BITS_PER_UNIT);
  else
    align = MAX (align, new_align == 0 ? 1 : new_align * BITS_PER_UNIT);

  return align;
}
\f
/* Verify that OBJECT, a type or decl, is something we can implement
   atomically.  If not, give an error for GNAT_ENTITY.  COMP_P is true
   if we require atomic components.  */

static void
check_ok_for_atomic (tree object, Entity_Id gnat_entity, bool comp_p)
{
  Node_Id gnat_error_point = gnat_entity;
  Node_Id gnat_node;
  enum machine_mode mode;
  unsigned int align;
  tree size;

  /* There are three case of what OBJECT can be.  It can be a type, in which
     case we take the size, alignment and mode from the type.  It can be a
     declaration that was indirect, in which case the relevant values are
     that of the type being pointed to, or it can be a normal declaration,
     in which case the values are of the decl.  The code below assumes that
     OBJECT is either a type or a decl.  */
  if (TYPE_P (object))
    {
      mode = TYPE_MODE (object);
      align = TYPE_ALIGN (object);
      size = TYPE_SIZE (object);
    }
  else if (DECL_BY_REF_P (object))
    {
      mode = TYPE_MODE (TREE_TYPE (TREE_TYPE (object)));
      align = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (object)));
      size = TYPE_SIZE (TREE_TYPE (TREE_TYPE (object)));
    }
  else
    {
      mode = DECL_MODE (object);
      align = DECL_ALIGN (object);
      size = DECL_SIZE (object);
    }

  /* Consider all floating-point types atomic and any types that that are
     represented by integers no wider than a machine word.  */
  if (GET_MODE_CLASS (mode) == MODE_FLOAT
      || ((GET_MODE_CLASS (mode) == MODE_INT
           || GET_MODE_CLASS (mode) == MODE_PARTIAL_INT)
          && GET_MODE_BITSIZE (mode) <= BITS_PER_WORD))
    return;

  /* For the moment, also allow anything that has an alignment equal
     to its size and which is smaller than a word.  */
  if (size && TREE_CODE (size) == INTEGER_CST
      && compare_tree_int (size, align) == 0
      && align <= BITS_PER_WORD)
    return;

  for (gnat_node = First_Rep_Item (gnat_entity); Present (gnat_node);
       gnat_node = Next_Rep_Item (gnat_node))
    {
      if (!comp_p && Nkind (gnat_node) == N_Pragma
          && Get_Pragma_Id (Chars (gnat_node)) == Pragma_Atomic)
        gnat_error_point = First (Pragma_Argument_Associations (gnat_node));
      else if (comp_p && Nkind (gnat_node) == N_Pragma
               && (Get_Pragma_Id (Chars (gnat_node))
                   == Pragma_Atomic_Components))
        gnat_error_point = First (Pragma_Argument_Associations (gnat_node));
    }

  if (comp_p)
    post_error_ne ("atomic access to component of & cannot be guaranteed",
                   gnat_error_point, gnat_entity);
  else
    post_error_ne ("atomic access to & cannot be guaranteed",
                   gnat_error_point, gnat_entity);
}
\f
/* Check if FTYPE1 and FTYPE2, two potentially different function type nodes,
   have compatible signatures so that a call using one type may be safely
   issued if the actual target function type is the other. Return 1 if it is
   the case, 0 otherwise, and post errors on the incompatibilities.

   This is used when an Ada subprogram is mapped onto a GCC builtin, to ensure
   that calls to the subprogram will have arguments suitable for the later
   underlying builtin expansion.  */

static int
compatible_signatures_p (tree ftype1, tree ftype2)
{
  /* As of now, we only perform very trivial tests and consider it's the
     programmer's responsibility to ensure the type correctness in the Ada
     declaration, as in the regular Import cases.

     Mismatches typically result in either error messages from the builtin
     expander, internal compiler errors, or in a real call sequence.  This
     should be refined to issue diagnostics helping error detection and
     correction.  */

  /* Almost fake test, ensuring a use of each argument.  */
  if (ftype1 == ftype2)
    return 1;

  return 1;
}
\f
/* Given a type T, a FIELD_DECL F, and a replacement value R, return a new type
   with all size expressions that contain F updated by replacing F with R.
   This is identical to GCC's substitute_in_type except that it knows about
   TYPE_INDEX_TYPE.  If F is NULL_TREE, always make a new RECORD_TYPE, even if
   nothing has changed.  */

tree
gnat_substitute_in_type (tree t, tree f, tree r)
{
  tree new = t;
  tree tem;

  switch (TREE_CODE (t))
    {
    case INTEGER_TYPE:
    case ENUMERAL_TYPE:
    case BOOLEAN_TYPE:
      if (CONTAINS_PLACEHOLDER_P (TYPE_MIN_VALUE (t))
          || CONTAINS_PLACEHOLDER_P (TYPE_MAX_VALUE (t)))
        {
          tree low = SUBSTITUTE_IN_EXPR (TYPE_MIN_VALUE (t), f, r);
          tree high = SUBSTITUTE_IN_EXPR (TYPE_MAX_VALUE (t), f, r);

          if (low == TYPE_MIN_VALUE (t) && high == TYPE_MAX_VALUE (t))
            return t;

          new = build_range_type (TREE_TYPE (t), low, high);
          if (TYPE_INDEX_TYPE (t))
            SET_TYPE_INDEX_TYPE
              (new, gnat_substitute_in_type (TYPE_INDEX_TYPE (t), f, r));
          return new;
        }

      return t;

    case REAL_TYPE:
      if (CONTAINS_PLACEHOLDER_P (TYPE_MIN_VALUE (t))
          || CONTAINS_PLACEHOLDER_P (TYPE_MAX_VALUE (t)))
        {
          tree low = NULL_TREE, high = NULL_TREE;

          if (TYPE_MIN_VALUE (t))
            low = SUBSTITUTE_IN_EXPR (TYPE_MIN_VALUE (t), f, r);
          if (TYPE_MAX_VALUE (t))
            high = SUBSTITUTE_IN_EXPR (TYPE_MAX_VALUE (t), f, r);

          if (low == TYPE_MIN_VALUE (t) && high == TYPE_MAX_VALUE (t))
            return t;

          t = copy_type (t);
          TYPE_MIN_VALUE (t) = low;
          TYPE_MAX_VALUE (t) = high;
        }
      return t;

    case COMPLEX_TYPE:
      tem = gnat_substitute_in_type (TREE_TYPE (t), f, r);
      if (tem == TREE_TYPE (t))
        return t;

      return build_complex_type (tem);

    case OFFSET_TYPE:
    case METHOD_TYPE:
    case FUNCTION_TYPE:
    case LANG_TYPE:
      /* Don't know how to do these yet.  */
      gcc_unreachable ();

    case ARRAY_TYPE:
      {
        tree component = gnat_substitute_in_type (TREE_TYPE (t), f, r);
        tree domain = gnat_substitute_in_type (TYPE_DOMAIN (t), f, r);

        if (component == TREE_TYPE (t) && domain == TYPE_DOMAIN (t))
          return t;

        new = build_array_type (component, domain);
        TYPE_SIZE (new) = 0;
        TYPE_MULTI_ARRAY_P (new) = TYPE_MULTI_ARRAY_P (t);
        TYPE_CONVENTION_FORTRAN_P (new) = TYPE_CONVENTION_FORTRAN_P (t);
        layout_type (new);
        TYPE_ALIGN (new) = TYPE_ALIGN (t);

        /* If we had bounded the sizes of T by a constant, bound the sizes of
           NEW by the same constant.  */
        if (TREE_CODE (TYPE_SIZE (t)) == MIN_EXPR)
          TYPE_SIZE (new)
            = size_binop (MIN_EXPR, TREE_OPERAND (TYPE_SIZE (t), 1),
                          TYPE_SIZE (new));
        if (TREE_CODE (TYPE_SIZE_UNIT (t)) == MIN_EXPR)
          TYPE_SIZE_UNIT (new)
            = size_binop (MIN_EXPR, TREE_OPERAND (TYPE_SIZE_UNIT (t), 1),
                          TYPE_SIZE_UNIT (new));
        return new;
      }

    case RECORD_TYPE:
    case UNION_TYPE:
    case QUAL_UNION_TYPE:
      {
        tree field;
        bool changed_field
          = (f == NULL_TREE && !TREE_CONSTANT (TYPE_SIZE (t)));
        bool field_has_rep = false;
        tree last_field = NULL_TREE;

        tree new = copy_type (t);

        /* Start out with no fields, make new fields, and chain them
           in.  If we haven't actually changed the type of any field,
           discard everything we've done and return the old type.  */

        TYPE_FIELDS (new) = NULL_TREE;
        TYPE_SIZE (new) = NULL_TREE;

        for (field = TYPE_FIELDS (t); field; field = TREE_CHAIN (field))
          {
            tree new_field = copy_node (field);

            TREE_TYPE (new_field)
              = gnat_substitute_in_type (TREE_TYPE (new_field), f, r);

            if (DECL_HAS_REP_P (field) && !DECL_INTERNAL_P (field))
              field_has_rep = true;
            else if (TREE_TYPE (new_field) != TREE_TYPE (field))
              changed_field = true;

            /* If this is an internal field and the type of this field is
               a UNION_TYPE or RECORD_TYPE with no elements, ignore it.  If
               the type just has one element, treat that as the field.
               But don't do this if we are processing a QUAL_UNION_TYPE.  */
            if (TREE_CODE (t) != QUAL_UNION_TYPE
                && DECL_INTERNAL_P (new_field)
                && (TREE_CODE (TREE_TYPE (new_field)) == UNION_TYPE
                    || TREE_CODE (TREE_TYPE (new_field)) == RECORD_TYPE))
              {
                if (!TYPE_FIELDS (TREE_TYPE (new_field)))
                  continue;

                if (!TREE_CHAIN (TYPE_FIELDS (TREE_TYPE (new_field))))
                  {
                    tree next_new_field
                      = copy_node (TYPE_FIELDS (TREE_TYPE (new_field)));

                    /* Make sure omitting the union doesn't change
                       the layout.  */
                    DECL_ALIGN (next_new_field) = DECL_ALIGN (new_field);
                    new_field = next_new_field;
                  }
              }

            DECL_CONTEXT (new_field) = new;
            SET_DECL_ORIGINAL_FIELD (new_field,
                                     (DECL_ORIGINAL_FIELD (field)
                                      ? DECL_ORIGINAL_FIELD (field) : field));

            /* If the size of the old field was set at a constant,
               propagate the size in case the type's size was variable.
               (This occurs in the case of a variant or discriminated
               record with a default size used as a field of another
               record.)  */
            DECL_SIZE (new_field)
              = TREE_CODE (DECL_SIZE (field)) == INTEGER_CST
                ? DECL_SIZE (field) : NULL_TREE;
            DECL_SIZE_UNIT (new_field)
              = TREE_CODE (DECL_SIZE_UNIT (field)) == INTEGER_CST
                ? DECL_SIZE_UNIT (field) : NULL_TREE;

            if (TREE_CODE (t) == QUAL_UNION_TYPE)
              {
                tree new_q = SUBSTITUTE_IN_EXPR (DECL_QUALIFIER (field), f, r);

                if (new_q != DECL_QUALIFIER (new_field))
                  changed_field = true;

                /* Do the substitution inside the qualifier and if we find
                   that this field will not be present, omit it.  */
                DECL_QUALIFIER (new_field) = new_q;

                if (integer_zerop (DECL_QUALIFIER (new_field)))
                  continue;
              }

            if (!last_field)
              TYPE_FIELDS (new) = new_field;
            else
              TREE_CHAIN (last_field) = new_field;

            last_field = new_field;

            /* If this is a qualified type and this field will always be
               present, we are done.  */
            if (TREE_CODE (t) == QUAL_UNION_TYPE
                && integer_onep (DECL_QUALIFIER (new_field)))
              break;
          }

        /* If this used to be a qualified union type, but we now know what
           field will be present, make this a normal union.  */
        if (changed_field && TREE_CODE (new) == QUAL_UNION_TYPE
            && (!TYPE_FIELDS (new)
                || integer_onep (DECL_QUALIFIER (TYPE_FIELDS (new)))))
          TREE_SET_CODE (new, UNION_TYPE);
        else if (!changed_field)
          return t;

        gcc_assert (!field_has_rep);
        layout_type (new);

        /* If the size was originally a constant use it.  */
        if (TYPE_SIZE (t) && TREE_CODE (TYPE_SIZE (t)) == INTEGER_CST
            && TREE_CODE (TYPE_SIZE (new)) != INTEGER_CST)
          {
            TYPE_SIZE (new) = TYPE_SIZE (t);
            TYPE_SIZE_UNIT (new) = TYPE_SIZE_UNIT (t);
            SET_TYPE_ADA_SIZE (new, TYPE_ADA_SIZE (t));
          }

        return new;
      }

    default:
      return t;
    }
}
\f
/* Return the "RM size" of GNU_TYPE.  This is the actual number of bits
   needed to represent the object.  */

tree
rm_size (tree gnu_type)
{
  /* For integer types, this is the precision.  For record types, we store
     the size explicitly.  For other types, this is just the size.  */

  if (INTEGRAL_TYPE_P (gnu_type) && TYPE_RM_SIZE (gnu_type))
    return TYPE_RM_SIZE (gnu_type);
  else if (TREE_CODE (gnu_type) == RECORD_TYPE
           && TYPE_CONTAINS_TEMPLATE_P (gnu_type))
    /* Return the rm_size of the actual data plus the size of the template.  */
    return
      size_binop (PLUS_EXPR,
                  rm_size (TREE_TYPE (TREE_CHAIN (TYPE_FIELDS (gnu_type)))),
                  DECL_SIZE (TYPE_FIELDS (gnu_type)));
  else if ((TREE_CODE (gnu_type) == RECORD_TYPE
            || TREE_CODE (gnu_type) == UNION_TYPE
            || TREE_CODE (gnu_type) == QUAL_UNION_TYPE)
           && !TYPE_IS_FAT_POINTER_P (gnu_type)
           && TYPE_ADA_SIZE (gnu_type))
    return TYPE_ADA_SIZE (gnu_type);
  else
    return TYPE_SIZE (gnu_type);
}
\f
/* Return an identifier representing the external name to be used for
   GNAT_ENTITY.  If SUFFIX is specified, the name is followed by "___"
   and the specified suffix.  */

tree
create_concat_name (Entity_Id gnat_entity, const char *suffix)
{
  Entity_Kind kind = Ekind (gnat_entity);

  const char *str = (!suffix ? "" : suffix);
  String_Template temp = {1, strlen (str)};
  Fat_Pointer fp = {str, &temp};

  Get_External_Name_With_Suffix (gnat_entity, fp);

  /* A variable using the Stdcall convention (meaning we are running
     on a Windows box) live in a DLL. Here we adjust its name to use
     the jump-table, the _imp__NAME contains the address for the NAME
     variable. */
  if ((kind == E_Variable || kind == E_Constant)
      && Has_Stdcall_Convention (gnat_entity))
    {
      const char *prefix = "_imp__";
      int k, plen = strlen (prefix);

      for (k = 0; k <= Name_Len; k++)
        Name_Buffer [Name_Len - k + plen] = Name_Buffer [Name_Len - k];
      strncpy (Name_Buffer, prefix, plen);
    }

  return get_identifier (Name_Buffer);
}

/* Return the name to be used for GNAT_ENTITY.  If a type, create a
   fully-qualified name, possibly with type information encoding.
   Otherwise, return the name.  */

tree
get_entity_name (Entity_Id gnat_entity)
{
  Get_Encoded_Name (gnat_entity);
  return get_identifier (Name_Buffer);
}

/* Given GNU_ID, an IDENTIFIER_NODE containing a name and SUFFIX, a
   string, return a new IDENTIFIER_NODE that is the concatenation of
   the name in GNU_ID and SUFFIX.  */

tree
concat_id_with_name (tree gnu_id, const char *suffix)
{
  int len = IDENTIFIER_LENGTH (gnu_id);

  strncpy (Name_Buffer, IDENTIFIER_POINTER (gnu_id),
           IDENTIFIER_LENGTH (gnu_id));
  strncpy (Name_Buffer + len, "___", 3);
  len += 3;
  strcpy (Name_Buffer + len, suffix);
  return get_identifier (Name_Buffer);
}

#include "gt-ada-decl.h"