[pf3gnuchains/gcc-fork.git] / gcc / ada / gcc-interface / decl.c

/****************************************************************************
 *                                                                          *
 *                         GNAT COMPILER COMPONENTS                         *
 *                                                                          *
 *                                 D E C L                                  *
 *                                                                          *
 *                          C Implementation File                           *
 *                                                                          *
 *          Copyright (C) 1992-2009, 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 3,  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 along with GCC; see the file COPYING3.  If not see        *
 * <http://www.gnu.org/licenses/>.                                          *
 *                                                                          *
 * 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 "ggc.h"
#include "target.h"
#include "expr.h"
#include "tree-inline.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 "ada-tree.h"
#include "gigi.h"

#ifndef MAX_FIXED_MODE_SIZE
#define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
#endif

/* 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

/* Stack realignment for functions with foreign conventions is provided on a
   per back-end basis now, as it is handled by the prologue expanders and not
   as part of the function's body any more.  It might be requested by way of a
   dedicated function type attribute on the targets that support it.

   We need a way to avoid setting the attribute on the targets that don't
   support it and use FORCE_PREFERRED_STACK_BOUNDARY_IN_MAIN for this purpose.

   It is defined on targets where the circuitry is available, and indicates
   whether the realignment is needed for 'main'.  We use this to decide for
   foreign subprograms as well.

   It is not defined on targets where the circuitry is not implemented, and
   we just never set the attribute in these cases.

   Whether it is defined on all targets that would need it in theory is
   not entirely clear.  We currently trust the base GCC settings for this
   purpose.  */

#ifndef FORCE_PREFERRED_STACK_BOUNDARY_IN_MAIN
#define FORCE_PREFERRED_STACK_BOUNDARY_IN_MAIN 0
#endif

struct incomplete
{
  struct incomplete *next;
  tree old_type;
  Entity_Id full_type;
};

/* These variables are used to defer recursively expanding incomplete types
   while we are processing an array, a record or a subprogram type.  */
static int defer_incomplete_level = 0;
static struct incomplete *defer_incomplete_list;

/* This variable is used to delay expanding From_With_Type types until the
   end of the spec.  */
static struct incomplete *defer_limited_with;

/* These variables are used to defer finalizing types.  The element of the
   list is the TYPE_DECL associated with the type.  */
static int defer_finalize_level = 0;
static VEC (tree,heap) *defer_finalize_list;

/* A hash table used 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;

enum alias_set_op
{
  ALIAS_SET_COPY,
  ALIAS_SET_SUBSET,
  ALIAS_SET_SUPERSET
};

static void relate_alias_sets (tree, tree, enum alias_set_op);

static bool allocatable_size_p (tree, bool);
static void prepend_one_attribute_to (struct attrib **,
                                      enum attr_type, tree, tree, Node_Id);
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 (tree, Entity_Id, tree, bool, bool);
static tree make_packable_type (tree, bool);
static tree gnat_to_gnu_component_type (Entity_Id, bool, bool);
static tree gnat_to_gnu_param (Entity_Id, Mechanism_Type, Entity_Id, bool,
                               bool *);
static tree gnat_to_gnu_field (Entity_Id, tree, int, bool, bool);
static bool same_discriminant_p (Entity_Id, Entity_Id);
static bool array_type_has_nonaliased_component (tree, Entity_Id);
static bool compile_time_known_address_p (Node_Id);
static bool cannot_be_superflat_p (Node_Id);
static void components_to_record (tree, Node_Id, tree, int, bool, tree *,
                                  bool, bool, bool, bool, bool);
static Uint annotate_value (tree);
static void annotate_rep (Entity_Id, tree);
static tree build_position_list (tree, bool, tree, tree, unsigned int, tree);
static tree build_subst_list (Entity_Id, Entity_Id, bool);
static tree build_variant_list (tree, tree, tree);
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 unsigned int ceil_alignment (unsigned HOST_WIDE_INT);
static void check_ok_for_atomic (tree, Entity_Id, bool);
static int compatible_signatures_p (tree, tree);
static tree create_field_decl_from (tree, tree, tree, tree, tree, tree);
static tree get_rep_part (tree);
static tree get_variant_part (tree);
static tree create_variant_part_from (tree, tree, tree, tree, tree);
static void copy_and_substitute_in_size (tree, tree, tree);
static void rest_of_type_decl_compilation_no_defer (tree);
\f
/* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
   entity, return the equivalent GCC tree for that entity (a ..._DECL node)
   and associate 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 a variable.  For
   a renamed entity, 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 is necessary to know whether an
   external declaration or a definition must 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)
{
  /* Contains the kind of the input GNAT node.  */
  const Entity_Kind kind = Ekind (gnat_entity);
  /* True if this is a type.  */
  const bool is_type = IN (kind, Type_Kind);
  /* For a type, contains the equivalent GNAT node to be used in gigi.  */
  Entity_Id gnat_equiv_type = Empty;
  /* Temporary used to walk the GNAT tree.  */
  Entity_Id gnat_temp;
  /* Contains the GCC DECL node which is equivalent to the input GNAT node.
     This node will be associated with the GNAT node by calling at the end
     of the `switch' statement.  */
  tree gnu_decl = NULL_TREE;
  /* Contains the GCC type to be used for the GCC node.  */
  tree gnu_type = NULL_TREE;
  /* Contains the GCC size tree to be used for the GCC node.  */
  tree gnu_size = NULL_TREE;
  /* Contains the GCC name to be used for the GCC node.  */
  tree gnu_entity_name;
  /* True if we have already saved gnu_decl as a GNAT association.  */
  bool saved = false;
  /* True if we incremented defer_incomplete_level.  */
  bool this_deferred = false;
  /* True if we incremented force_global.  */
  bool this_global = false;
  /* True if we should check to see if elaborated during processing.  */
  bool maybe_present = false;
  /* True if we made GNU_DECL and its type here.  */
  bool this_made_decl = false;
  /* True if debug info is requested for this entity.  */
  bool debug_info_p = (Needs_Debug_Info (gnat_entity)
                       || debug_info_level == DINFO_LEVEL_VERBOSE);
  /* True if this entity is to be considered as imported.  */
  bool imported_p = (Is_Imported (gnat_entity)
                     && No (Address_Clause (gnat_entity)));
  /* Size and alignment of the GCC node, if meaningful.  */
  unsigned int esize = 0, align = 0;
  /* Contains the list of attributes directly attached to the entity.  */
  struct attrib *attr_list = NULL;

  /* 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_type
      && 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 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 Itype has an incorrect scope, i.e. that its
         scope does not correspond to the subprogram it is declared in.  */
      gcc_unreachable ();
    }

  /* 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 ((!definition || (is_type && imported_p))
      && present_gnu_tree (gnat_entity))
    {
      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)));

  /* The 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)));

  /* If we get here, it means we have not yet done anything with this entity.
     If we are not defining it, it must be a type or an entity that is defined
     elsewhere or externally, otherwise we should have defined it already.  */
  gcc_assert (definition
              || type_annotate_only
              || is_type
              || kind == E_Discriminant
              || kind == E_Component
              || kind == E_Label
              || (kind == E_Constant && Present (Full_View (gnat_entity)))
              || Is_Public (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_name = get_entity_name (gnat_entity);
  Sloc_to_locus (Sloc (gnat_entity), &input_location);

  /* 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.  */
  if (!definition
      && kind != E_Component
      && kind != E_Discriminant
      && Is_Public (gnat_entity)
      && !Is_Statically_Allocated (gnat_entity))
    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);

  /* Do some common processing for types.  */
  if (is_type)
    {
      /* Compute the equivalent type to be used in gigi.  */
      gnat_equiv_type = Gigi_Equivalent_Type (gnat_entity);

      /* 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 (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);

      /* Compute a default value for the size of the type.  */
      if (Known_Esize (gnat_entity)
          && UI_Is_In_Int_Range (Esize (gnat_entity)))
        {
          unsigned int max_esize;
          esize = UI_To_Int (Esize (gnat_entity));

          if (IN (kind, Float_Kind))
            max_esize = fp_prec_to_size (LONG_DOUBLE_TYPE_SIZE);
          else if (IN (kind, Access_Kind))
            max_esize = POINTER_SIZE * 2;
          else
            max_esize = LONG_LONG_TYPE_SIZE;

          if (esize > max_esize)
           esize = max_esize;
        }
      else
        esize = LONG_LONG_TYPE_SIZE;
    }

  switch (kind)
    {
    case E_Constant:
      /* If this is a use of a deferred constant without address clause,
         get its full definition.  */
      if (!definition
          && No (Address_Clause (gnat_entity))
          && 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 or allocator, 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)
          && (Nkind (Expression (Declaration_Node (gnat_entity)))
              != N_Allocator))
        gnu_expr = gnat_to_gnu (Expression (Declaration_Node (gnat_entity)));

      /* Ignore deferred constant definitions without address clause since
         they are processed fully in the front-end.  If No_Initialization
         is set, this is not a deferred constant but a constant whose value
         is built manually.  And constants that are renamings are handled
         like variables.  */
      if (definition
          && !gnu_expr
          && No (Address_Clause (gnat_entity))
          && !No_Initialization (Declaration_Node (gnat_entity))
          && No (Renamed_Object (gnat_entity)))
        {
          gnu_decl = error_mark_node;
          saved = true;
          break;
        }

      /* Ignore constant definitions already marked with the error node.  See
         the N_Object_Declaration case of gnat_to_gnu for the rationale.  */
      if (definition
          && gnu_expr
          && present_gnu_tree (gnat_entity)
          && get_gnu_tree (gnat_entity) == error_mark_node)
        {
          maybe_present = 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
             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_True_Constant (gnat_entity)
             && !Treat_As_Volatile (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;
        tree gnu_object_size;

        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));

        /* For a debug renaming declaration, build a pure debug entity.  */
        if (Present (Debug_Renaming_Link (gnat_entity)))
          {
            rtx addr;
            gnu_decl = build_decl (input_location,
                                   VAR_DECL, gnu_entity_name, gnu_type);
            /* The (MEM (CONST (0))) pattern is prescribed by STABS.  */
            if (global_bindings_p ())
              addr = gen_rtx_CONST (VOIDmode, const0_rtx);
            else
              addr = stack_pointer_rtx;
            SET_DECL_RTL (gnu_decl, gen_rtx_MEM (Pmode, addr));
            gnat_pushdecl (gnu_decl, gnat_entity);
            break;
          }

        /* 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 an alignment.  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));
            /* No point in changing the type if there is an address clause
               as the final type of the object will be a reference type.  */
            if (Present (Address_Clause (gnat_entity)))
              align = 0;
            else
              gnu_type
                = maybe_pad_type (gnu_type, NULL_TREE, align, gnat_entity,
                                  false, false, definition, true);
          }

        /* 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)
              {
                tree size = TYPE_SIZE (TREE_TYPE (gnu_expr));
                if (CONTAINS_PLACEHOLDER_P (size))
                  {
                    /* If the initializing expression is itself a constant,
                       despite having a nominal type with self-referential
                       size, we can get the size directly from it.  */
                    if (TREE_CODE (gnu_expr) == COMPONENT_REF
                        && TYPE_IS_PADDING_P
                           (TREE_TYPE (TREE_OPERAND (gnu_expr, 0)))
                        && TREE_CODE (TREE_OPERAND (gnu_expr, 0)) == VAR_DECL
                        && (TREE_READONLY (TREE_OPERAND (gnu_expr, 0))
                            || DECL_READONLY_ONCE_ELAB
                               (TREE_OPERAND (gnu_expr, 0))))
                      gnu_size = DECL_SIZE (TREE_OPERAND (gnu_expr, 0));
                    else
                      gnu_size
                        = SUBSTITUTE_PLACEHOLDER_IN_EXPR (size, gnu_expr);
                  }
                else
                  gnu_size = size;
              }
            /* 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)
              && !TREE_OVERFLOW (gnu_size))
             || (TYPE_SIZE (gnu_type)
                 && integer_zerop (TYPE_SIZE (gnu_type))
                 && !TREE_OVERFLOW (TYPE_SIZE (gnu_type))))
            && (!Is_Constr_Subt_For_UN_Aliased (Etype (gnat_entity))
                || !Is_Array_Type (Etype (gnat_entity)))
            && No (Renamed_Object (gnat_entity))
            && No (Address_Clause (gnat_entity)))
          gnu_size = bitsize_unit_node;

        /* If this is an object with no specified size and alignment, and
           if either it is atomic or we are not optimizing alignment for
           space and it is composite and not an exception, an Out parameter
           or a reference to another object, and the size of its type is a
           constant, set the alignment to the smallest one which is not
           smaller than the size, with an appropriate cap.  */
        if (!gnu_size && align == 0
            && (Is_Atomic (gnat_entity)
                || (!Optimize_Alignment_Space (gnat_entity)
                    && kind != E_Exception
                    && kind != E_Out_Parameter
                    && Is_Composite_Type (Etype (gnat_entity))
                    && !Is_Constr_Subt_For_UN_Aliased (Etype (gnat_entity))
                    && !imported_p
                    && No (Renamed_Object (gnat_entity))
                    && No (Address_Clause (gnat_entity))))
            && TREE_CODE (TYPE_SIZE (gnu_type)) == INTEGER_CST)
          {
            /* No point in jumping through all the hoops needed in order
               to support BIGGEST_ALIGNMENT if we don't really have to.
               So we cap to the smallest alignment that corresponds to
               a known efficient memory access pattern of the target.  */
            unsigned int align_cap = Is_Atomic (gnat_entity)
                                     ? BIGGEST_ALIGNMENT
                                     : get_mode_alignment (ptr_mode);

            if (!host_integerp (TYPE_SIZE (gnu_type), 1)
                || compare_tree_int (TYPE_SIZE (gnu_type), align_cap) >= 0)
              align = align_cap;
            else
              align = ceil_alignment (tree_low_cst (TYPE_SIZE (gnu_type), 1));

            /* But make sure not to under-align the object.  */
            if (align <= TYPE_ALIGN (gnu_type))
              align = 0;

            /* And honor the minimum valid atomic alignment, if any.  */
#ifdef MINIMUM_ATOMIC_ALIGNMENT
            else if (align < MINIMUM_ATOMIC_ALIGNMENT)
              align = MINIMUM_ATOMIC_ALIGNMENT;
#endif
          }

        /* 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_name (gnu_entity_name,
                                                           "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.
           But do not take into account alignment promotions to compute the
           size of the object.  */
        gnu_object_size = gnu_size ? gnu_size : TYPE_SIZE (gnu_type);
        if (gnu_size || align > 0)
          gnu_type = maybe_pad_type (gnu_type, gnu_size, align, gnat_entity,
                                     false, false, definition,
                                     gnu_size ? true : false);

        /* If this is a renaming, avoid as much as possible to create a new
           object.  However, in several cases, creating it is required.
           This processing needs to be applied to the raw expression so
           as to make it more likely to rename the underlying object.  */
        if (Present (Renamed_Object (gnat_entity)))
          {
            bool create_normal_object = false;

            /* 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
                 && TYPE_IS_PADDING_P (TREE_TYPE (TREE_OPERAND (gnu_expr, 0))))
                /* Strip useless conversions around the object.  */
                || (TREE_CODE (gnu_expr) == NOP_EXPR
                    && gnat_types_compatible_p
                       (TREE_TYPE (gnu_expr),
                        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 stemming from a function
               call, treat it as a normal object whose initial value is what
               is being renamed.  RM 3.3 says that the result of evaluating a
               function call is a constant object.  As a consequence, it can
               be the inner object of a constant renaming.  In this case, the
               renaming must be fully instantiated, i.e. it cannot be a mere
               reference to (part of) an existing object.  */
            if (const_flag)
              {
                tree inner_object = gnu_expr;
                while (handled_component_p (inner_object))
                  inner_object = TREE_OPERAND (inner_object, 0);
                if (TREE_CODE (inner_object) == CALL_EXPR)
                  create_normal_object = true;
              }

            /* Otherwise, see if we can proceed with a stabilized version of
               the renamed entity or if we need to make a new object.  */
            if (!create_normal_object)
              {
                tree maybe_stable_expr = NULL_TREE;
                bool stable = false;

                /* 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, &stable);

                    if (stable)
                      {
                        /* ??? No DECL_EXPR is created so we need to mark
                           the expression manually lest it is shared.  */
                        if (global_bindings_p ())
                          MARK_VISITED (maybe_stable_expr);
                        gnu_decl = maybe_stable_expr;
                        save_gnu_tree (gnat_entity, gnu_decl, true);
                        saved = true;
                        annotate_object (gnat_entity, gnu_type, NULL_TREE,
                                         false);
                        break;
                      }

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

                /* Case 3: If this is a constant renaming and creating a
                   new object is allowed and cheap, treat it as a normal
                   object whose initial value is what is being renamed.  */
                if (const_flag
                    && !Is_Composite_Type
                        (Underlying_Type (Etype (gnat_entity))))
                  ;

                /* Case 4: Make this into a constant pointer to the object we
                   are to rename and attach the object to the pointer if it is
                   something we can stabilize.

                   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.
                   The pointer is called a "renaming" pointer in this case.

                   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.  */
                else
                  {
                    gnu_type = build_reference_type (gnu_type);
                    inner_const_flag = TREE_READONLY (gnu_expr);
                    const_flag = true;

                    /* If the previous attempt at stabilizing failed, there
                       is no point in trying again and we 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 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.

                       These SAVE_EXPRs will be evaluated at the right place
                       by either the evaluation of the initializer for the
                       non-global case or the elaboration code for the global
                       case, and will be attached to the elaboration procedure
                       in the latter case.  */
                    else
                     {
                        maybe_stable_expr
                          = maybe_stabilize_reference (gnu_expr, true, &stable);

                        if (stable)
                          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;
                  }
              }
          }

        /* Make a volatile version of this object's type if we are to make
           the object volatile.  We also interpret 13.3(19) conservatively
           and disallow any optimizations for such a non-constant object.  */
        if ((Treat_As_Volatile (gnat_entity)
             || (!const_flag
                 && (Is_Exported (gnat_entity)
                     || Is_Imported (gnat_entity)
                     || Present (Address_Clause (gnat_entity)))))
            && !TYPE_VOLATILE (gnu_type))
          gnu_type = build_qualified_type (gnu_type,
                                           (TYPE_QUALS (gnu_type)
                                            | TYPE_QUAL_VOLATILE));

        /* If we are defining 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.  */
        if (definition
            && !gnu_expr
            && TREE_CODE (gnu_type) == RECORD_TYPE
            && (TYPE_CONTAINS_TEMPLATE_P (gnu_type)
                /* Beware that padding might have been introduced above.  */
                || (TYPE_PADDING_P (gnu_type)
                    && TREE_CODE (TREE_TYPE (TYPE_FIELDS (gnu_type)))
                       == RECORD_TYPE
                    && TYPE_CONTAINS_TEMPLATE_P
                       (TREE_TYPE (TYPE_FIELDS (gnu_type))))))
          {
            tree template_field
              = TYPE_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));
          }

        /* 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))
            && !(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 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_IS_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
           either get the address expression from the saved GCC tree for the
           object if it has a Freeze node, or elaborate the address expression
           here since the front-end has guaranteed that the elaboration has no
           effects in this case.  */
        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)
              || compile_time_known_address_p (Expression (Address_Clause
                                                           (gnat_entity)));

            /* If this is a deferred constant, the initializer is attached to
               the full view.  */
            if (kind == E_Constant && Present (Full_View (gnat_entity)))
              gnu_expr
                = gnat_to_gnu
                    (Expression (Declaration_Node (Full_View (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;

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

            /* If it has an address clause whose value is known at compile
               time, make the object a CONST_DECL.  This will avoid a
               useless dereference.  */
            if (Present (Address_Clause (gnat_entity)))
              {
                Node_Id gnat_address
                  = Expression (Address_Clause (gnat_entity));

                if (compile_time_known_address_p (gnat_address))
                  {
                    gnu_expr = gnat_to_gnu (gnat_address);
                    const_flag = true;
                  }
              }

            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,
                                     Empty, Empty, 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 largest stack alignment the back-end can honor, resort to
           a variable of "aligning type".  */
        if (!global_bindings_p () && !static_p && definition
            && !imported_p && TYPE_ALIGN (gnu_type) > BIGGEST_ALIGNMENT)
          {
            /* Create the new variable.  No need for extra room before the
               aligned field as this is in automatic storage.  */
            tree gnu_new_type
              = make_aligning_type (gnu_type, TYPE_ALIGN (gnu_type),
                                    TYPE_SIZE_UNIT (gnu_type),
                                    BIGGEST_ALIGNMENT, 0);
            tree 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);

            /* Initialize the aligned field if we have an initializer.  */
            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);

            /* And setup this entity as a reference to the aligned field.  */
            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))
            && !(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, NULL);

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

        gnu_decl = create_var_decl (gnu_entity_name, 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_UNIT (gnu_decl)
            && get_block_jmpbuf_decl ()
            && (TREE_CODE (DECL_SIZE_UNIT (gnu_decl)) != INTEGER_CST
                || (flag_stack_check == GENERIC_STACK_CHECK
                    && compare_tree_int (DECL_SIZE_UNIT (gnu_decl),
                                         STACK_CHECK_MAX_VAR_SIZE) > 0)))
          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 we are defining an Out parameter and we're not optimizing,
           create a fake PARM_DECL for debugging purposes and make it
           point to the VAR_DECL.  Suppress debug info for the latter
           but make sure it will still live on the stack so it can be
           accessed from within the debugger through the PARM_DECL.  */
        if (kind == E_Out_Parameter && definition && !optimize)
          {
            tree param = create_param_decl (gnu_entity_name, gnu_type, false);
            gnat_pushdecl (param, gnat_entity);
            SET_DECL_VALUE_EXPR (param, gnu_decl);
            DECL_HAS_VALUE_EXPR_P (param) = 1;
            if (debug_info_p)
              debug_info_p = false;
            else
              DECL_IGNORED_P (param) = 1;
            TREE_ADDRESSABLE (gnu_decl) = 1;
          }

        /* 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) && No (Address_Clause (gnat_entity)))
                || !optimize
                || Address_Taken (gnat_entity)
                || Is_Aliased (gnat_entity)
                || Is_Aliased (Etype (gnat_entity))))
          {
            tree gnu_corr_var
              = create_true_var_decl (gnu_entity_name, gnu_ext_name, gnu_type,
                                      gnu_expr, true, Is_Public (gnat_entity),
                                      !definition, static_p, attr_list,
                                      gnat_entity);

            SET_DECL_CONST_CORRESPONDING_VAR (gnu_decl, gnu_corr_var);

            /* As debugging information will be generated for the variable,
               do not generate information for the constant.  */
            DECL_IGNORED_P (gnu_decl) = 1;
          }

        /* 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 Esize and Alignment of the object if not already
           known.  Note that we pick the values of the type, not those of
           the object, to shield ourselves from low-level platform-dependent
           adjustments like alignment promotion.  This is both consistent with
           all the treatment above, where alignment and size are set on the
           type of the object and not on the object directly, and makes it
           possible to support all confirming representation clauses.  */
        annotate_object (gnat_entity, TREE_TYPE (gnu_decl), gnu_object_size,
                         used_by_ref);
      }
      break;

    case E_Void:
      /* Return a TYPE_DECL for "void" that we previously made.  */
      gnu_decl = TYPE_NAME (void_type_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_name;

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

      {
        /* We have a list of enumeral constants in First_Literal.  We make a
           CONST_DECL for each one and build into GNU_LITERAL_LIST the list to
           be placed into TYPE_FIELDS.  Each node in the list is a TREE_LIST
           whose TREE_VALUE is the literal name and whose TREE_PURPOSE is the
           value of the literal.  But when we have a regular boolean type, we
           simplify this a little by using a BOOLEAN_TYPE.  */
        bool is_boolean = Is_Boolean_Type (gnat_entity)
                          && !Has_Non_Standard_Rep (gnat_entity);
        tree gnu_literal_list = NULL_TREE;
        Entity_Id gnat_literal;

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

        TREE_SET_CODE (gnu_type, is_boolean ? BOOLEAN_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);
          }

        if (!is_boolean)
          TYPE_VALUES (gnu_type) = nreverse (gnu_literal_list);

        /* Note that the bounds are updated at the end of this function
           to avoid an infinite recursion since they refer to the 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.  */
        tree gnu_modulus, gnu_high = NULL_TREE;

        /* Packed array types are supposed to be subtypes only.  */
        gcc_assert (!Is_Packed_Array_Type (gnat_entity));

        gnu_type = make_unsigned_type (esize);

        /* 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 the upper bound is not maximal, make an extra subtype.  */
        if (gnu_high
            && !tree_int_cst_equal (gnu_high, TYPE_MAX_VALUE (gnu_type)))
          {
            tree gnu_subtype = make_unsigned_type (esize);
            SET_TYPE_RM_MAX_VALUE (gnu_subtype, gnu_high);
            TREE_TYPE (gnu_subtype) = gnu_type;
            TYPE_EXTRA_SUBTYPE_P (gnu_subtype) = 1;
            TYPE_NAME (gnu_type) = create_concat_name (gnat_entity, "UMT");
            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 create_range_type since we would like each subtype
         node to be distinct.  ??? Historically this was in preparation for
         when memory aliasing is implemented, but that's obsolete now given
         the call to relate_alias_sets below.

         The TREE_TYPE field of the INTEGER_TYPE points to the base 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
         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);

      /* Set the precision to the Esize except for bit-packed arrays.  */
      if (Is_Packed_Array_Type (gnat_entity)
          && Is_Bit_Packed_Array (Original_Array_Type (gnat_entity)))
        esize = UI_To_Int (RM_Size (gnat_entity));

      /* This should be an unsigned type if the base type is unsigned or
         if the lower bound is constant and non-negative or if the type
         is biased.  */
      if (Is_Unsigned_Type (Etype (gnat_entity))
          || Is_Unsigned_Type (gnat_entity)
          || Has_Biased_Representation (gnat_entity))
        gnu_type = make_unsigned_type (esize);
      else
        gnu_type = make_signed_type (esize);
      TREE_TYPE (gnu_type) = get_unpadded_type (Etype (gnat_entity));

      SET_TYPE_RM_MIN_VALUE
        (gnu_type,
         convert (TREE_TYPE (gnu_type),
                  elaborate_expression (Type_Low_Bound (gnat_entity),
                                        gnat_entity, get_identifier ("L"),
                                        definition, true,
                                        Needs_Debug_Info (gnat_entity))));

      SET_TYPE_RM_MAX_VALUE
        (gnu_type,
         convert (TREE_TYPE (gnu_type),
                  elaborate_expression (Type_High_Bound (gnat_entity),
                                        gnat_entity, get_identifier ("U"),
                                        definition, true,
                                        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);

      /* Attach the TYPE_STUB_DECL in case we have a parallel type.  */
      TYPE_STUB_DECL (gnu_type)
        = create_type_stub_decl (gnu_entity_name, 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.  */
      relate_alias_sets (gnu_type, TREE_TYPE (gnu_type), ALIAS_SET_COPY);

      /* For a packed array, make the original array type a parallel type.  */
      if (debug_info_p
          && Is_Packed_Array_Type (gnat_entity)
          && present_gnu_tree (Original_Array_Type (gnat_entity)))
        add_parallel_type (TYPE_STUB_DECL (gnu_type),
                           gnat_to_gnu_type
                           (Original_Array_Type (gnat_entity)));

      /* If the type we are dealing with represents a bit-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 up
         the modular type in an enclosing record type.  */
      if (Is_Packed_Array_Type (gnat_entity)
          && Is_Bit_Packed_Array (Original_Array_Type (gnat_entity)))
        {
          tree gnu_field_type, gnu_field;

          /* Set the RM size before wrapping up the type.  */
          SET_TYPE_RM_SIZE (gnu_type,
                            UI_To_gnu (RM_Size (gnat_entity), bitsizetype));
          TYPE_PACKED_ARRAY_TYPE_P (gnu_type) = 1;
          gnu_field_type = gnu_type;

          gnu_type = make_node (RECORD_TYPE);
          TYPE_NAME (gnu_type) = create_concat_name (gnat_entity, "JM");

          /* Propagate the alignment of the modular type to the record.
             This means that bit-packed arrays have "ceil" alignment for
             their size, which may seem counter-intuitive but makes it
             possible to easily overlay them on modular types.  */
          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 (gnu_entity_name, 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);

          /* Do not emit debug info until after the parallel type is added.  */
          finish_record_type (gnu_type, gnu_field, 0, false);
          TYPE_JUSTIFIED_MODULAR_P (gnu_type) = 1;

          relate_alias_sets (gnu_type, gnu_field_type, ALIAS_SET_COPY);

          if (debug_info_p)
            {
              /* Make the original array type a parallel type.  */
              if (present_gnu_tree (Original_Array_Type (gnat_entity)))
                add_parallel_type (TYPE_STUB_DECL (gnu_type),
                                   gnat_to_gnu_type
                                   (Original_Array_Type (gnat_entity)));

              rest_of_record_type_compilation (gnu_type);
            }
        }

      /* If the type we are dealing with has got a smaller alignment than the
         natural one, we need to wrap it up in a record type and under-align
         the latter.  We reuse the padding machinery for this purpose.  */
      else if (Present (Alignment_Clause (gnat_entity))
               && UI_Is_In_Int_Range (Alignment (gnat_entity))
               && (align = UI_To_Int (Alignment (gnat_entity)) * BITS_PER_UNIT)
               && align < TYPE_ALIGN (gnu_type))
        {
          tree gnu_field_type, gnu_field;

          /* Set the RM size before wrapping up the type.  */
          SET_TYPE_RM_SIZE (gnu_type,
                            UI_To_gnu (RM_Size (gnat_entity), bitsizetype));
          gnu_field_type = gnu_type;

          gnu_type = make_node (RECORD_TYPE);
          TYPE_NAME (gnu_type) = create_concat_name (gnat_entity, "PAD");

          TYPE_ALIGN (gnu_type) = align;
          TYPE_PACKED (gnu_type) = 1;

          /* Create a stripped-down declaration of the original type, mainly
             for debugging.  */
          create_type_decl (gnu_entity_name, 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, 0, debug_info_p);
          TYPE_PADDING_P (gnu_type) = 1;

          relate_alias_sets (gnu_type, gnu_field_type, ALIAS_SET_COPY);
        }

      /* Otherwise reset the alignment lest we computed it above.  */
      else
        align = 0;

      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_GCC_MIN_VALUE (gnu_type)
          = TYPE_GCC_MIN_VALUE (TREE_TYPE (gnu_type));
        TYPE_GCC_MAX_VALUE (gnu_type)
          = TYPE_GCC_MAX_VALUE (TREE_TYPE (gnu_type));
        layout_type (gnu_type);

        SET_TYPE_RM_MIN_VALUE
          (gnu_type,
           convert (TREE_TYPE (gnu_type),
                    elaborate_expression (Type_Low_Bound (gnat_entity),
                                          gnat_entity, get_identifier ("L"),
                                          definition, true,
                                          Needs_Debug_Info (gnat_entity))));

        SET_TYPE_RM_MAX_VALUE
          (gnu_type,
           convert (TREE_TYPE (gnu_type),
                    elaborate_expression (Type_High_Bound (gnat_entity),
                                          gnat_entity, get_identifier ("U"),
                                          definition, true,
                                          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;
          }

        /* Inherit our alias set from what we're a subtype of, as for
           integer subtypes.  */
        relate_alias_sets (gnu_type, TREE_TYPE (gnu_type), ALIAS_SET_COPY);
      }
    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:
      {
        Entity_Id gnat_index, gnat_name;
        const bool convention_fortran_p
          = (Convention (gnat_entity) == Convention_Fortran);
        const int ndim = Number_Dimensions (gnat_entity);
        tree gnu_template_fields = NULL_TREE;
        tree gnu_template_type = make_node (RECORD_TYPE);
        tree gnu_template_reference;
        tree gnu_ptr_template = build_pointer_type (gnu_template_type);
        tree gnu_fat_type = make_node (RECORD_TYPE);
        tree *gnu_index_types = (tree *) alloca (ndim * sizeof (tree));
        tree *gnu_temp_fields = (tree *) alloca (ndim * sizeof (tree));
        tree gnu_max_size = size_one_node, gnu_max_size_unit, tem;
        int index;

        TYPE_NAME (gnu_template_type)
          = create_concat_name (gnat_entity, "XUB");

        /* 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,
                                                   NULL_TREE, NULL_TREE, 0)),
                       create_field_decl (get_identifier ("P_BOUNDS"),
                                          gnu_ptr_template,
                                          gnu_fat_type, 0,
                                          NULL_TREE, NULL_TREE, 0));

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

        /* Do not emit debug info for this record type since the types of its
           fields are still incomplete at this point.  */
        finish_record_type (gnu_fat_type, tem, 0, false);
        TYPE_FAT_POINTER_P (gnu_fat_type) = 1;

        /* 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 = (convention_fortran_p ? ndim - 1 : 0),
             gnat_index = First_Index (gnat_entity);
             0 <= index && index < ndim;
             index += (convention_fortran_p ? - 1 : 1),
             gnat_index = Next_Index (gnat_index))
          {
            char field_name[16];
            tree gnu_index_base_type
              = get_unpadded_type (Base_Type (Etype (gnat_index)));
            tree gnu_low_field, gnu_high_field, gnu_low, gnu_high, gnu_max;

            /* Make the FIELD_DECLs for the low and high bounds of this
               type and then make extractions of these fields from the
               template.  */
            sprintf (field_name, "LB%d", index);
            gnu_low_field = create_field_decl (get_identifier (field_name),
                                               gnu_index_base_type,
                                               gnu_template_type, 0,
                                               NULL_TREE, NULL_TREE, 0);
            Sloc_to_locus (Sloc (gnat_entity),
                           &DECL_SOURCE_LOCATION (gnu_low_field));

            field_name[0] = 'U';
            gnu_high_field = create_field_decl (get_identifier (field_name),
                                                gnu_index_base_type,
                                                gnu_template_type, 0,
                                                NULL_TREE, NULL_TREE, 0);
            Sloc_to_locus (Sloc (gnat_entity),
                           &DECL_SOURCE_LOCATION (gnu_high_field));

            gnu_temp_fields[index] = chainon (gnu_low_field, gnu_high_field);

            /* We can't use build_component_ref here since the template type
               isn't complete yet.  */
            gnu_low = build3 (COMPONENT_REF, gnu_index_base_type,
                              gnu_template_reference, gnu_low_field,
                              NULL_TREE);
            gnu_high = build3 (COMPONENT_REF, gnu_index_base_type,
                               gnu_template_reference, gnu_high_field,
                               NULL_TREE);
            TREE_READONLY (gnu_low) = TREE_READONLY (gnu_high) = 1;

            /* Compute the size of this dimension.  */
            gnu_max
              = build3 (COND_EXPR, gnu_index_base_type,
                        build2 (GE_EXPR, integer_type_node, gnu_high, gnu_low),
                        gnu_high,
                        build2 (MINUS_EXPR, gnu_index_base_type,
                                gnu_low, fold_convert (gnu_index_base_type,
                                                       integer_one_node)));

            /* Make a range type with the new range in the Ada base type.
               Then make an index type with the size range in sizetype.  */
            gnu_index_types[index]
              = create_index_type (convert (sizetype, gnu_low),
                                   convert (sizetype, gnu_max),
                                   create_range_type (gnu_index_base_type,
                                                      gnu_low, gnu_high),
                                   gnat_entity);

            /* Update the maximum size of the array in elements.  */
            if (gnu_max_size)
              {
                tree gnu_index_type = get_unpadded_type (Etype (gnat_index));
                tree gnu_min
                  = convert (sizetype, TYPE_MIN_VALUE (gnu_index_type));
                tree gnu_max
                  = convert (sizetype, TYPE_MAX_VALUE (gnu_index_type));
                tree gnu_this_max
                  = size_binop (MAX_EXPR,
                                size_binop (PLUS_EXPR, size_one_node,
                                            size_binop (MINUS_EXPR,
                                                        gnu_max, gnu_min)),
                                size_zero_node);

                if (TREE_CODE (gnu_this_max) == INTEGER_CST
                    && TREE_OVERFLOW (gnu_this_max))
                  gnu_max_size = NULL_TREE;
                else
                  gnu_max_size
                    = size_binop (MULT_EXPR, gnu_max_size, gnu_this_max);
              }

            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, 0,
                            debug_info_p);
        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_component_type (gnat_entity, definition,
                                          debug_info_p);

        /* 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)));

        /* Compute the maximum size of the array in units and bits.  */
        if (gnu_max_size)
          {
            gnu_max_size_unit = size_binop (MULT_EXPR, gnu_max_size,
                                            TYPE_SIZE_UNIT (tem));
            gnu_max_size = size_binop (MULT_EXPR,
                                       convert (bitsizetype, gnu_max_size),
                                       TYPE_SIZE (tem));
          }
        else
          gnu_max_size_unit = NULL_TREE;

        /* Now build the array type.  */
        for (index = ndim - 1; index >= 0; index--)
          {
            tem = build_array_type (tem, gnu_index_types[index]);
            TYPE_MULTI_ARRAY_P (tem) = (index > 0);
            if (array_type_has_nonaliased_component (tem, gnat_entity))
              TYPE_NONALIASED_COMPONENT (tem) = 1;
          }

        /* If an alignment is specified, use it if valid.  But ignore it
           for the original type of packed array types.  If the alignment
           was requested with an explicit alignment clause, state so.  */
        if (No (Packed_Array_Type (gnat_entity))
            && Known_Alignment (gnat_entity))
          {
            TYPE_ALIGN (tem)
              = validate_alignment (Alignment (gnat_entity), gnat_entity,
                                    TYPE_ALIGN (tem));
            if (Present (Alignment_Clause (gnat_entity)))
              TYPE_USER_ALIGN (tem) = 1;
          }

        TYPE_CONVENTION_FORTRAN_P (tem) = convention_fortran_p;
        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;
        SET_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 (gnu_max_size
            && 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))
          {
            TYPE_SIZE (tem) = size_binop (MIN_EXPR, gnu_max_size,
                                          TYPE_SIZE (tem));
            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);

        /* Give the fat pointer type a name.  If this is a packed type, tell
           the debugger how to interpret the underlying bits.  */
        if (Present (Packed_Array_Type (gnat_entity)))
          gnat_name = Packed_Array_Type (gnat_entity);
        else
          gnat_name = gnat_entity;
        create_type_decl (create_concat_name (gnat_name, "XUP"),
                          gnu_fat_type, NULL, true,
                          debug_info_p, gnat_entity);

       /* Create the type to be used as what a thin pointer designates: an
          record type for the object and its template with the field offsets
          shifted to have the template at a negative offset.  */
        tem = build_unc_object_type (gnu_template_type, tem,
                                     create_concat_name (gnat_name, "XUT"));
        shift_unc_components_for_thin_pointers (tem);

        SET_TYPE_UNCONSTRAINED_ARRAY (tem, gnu_type);
        TYPE_OBJECT_RECORD_TYPE (gnu_type) = tem;
      }
      break;

    case E_String_Subtype:
    case E_Array_Subtype:

      /* This is the actual data type for array variables.  Multidimensional
         arrays are implemented as arrays of arrays.  Note that 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))
        ;
      else
        {
          Entity_Id gnat_index, gnat_base_index;
          const bool convention_fortran_p
            = (Convention (gnat_entity) == Convention_Fortran);
          const int ndim = Number_Dimensions (gnat_entity);
          tree gnu_base_type = gnu_type;
          tree *gnu_index_types = (tree *) alloca (ndim * sizeof (tree));
          tree gnu_max_size = size_one_node, gnu_max_size_unit;
          bool need_index_type_struct = false;
          int index;

          /* First create the GCC type for each index and find out whether
             special types are needed for debugging information.  */
          for (index = (convention_fortran_p ? ndim - 1 : 0),
               gnat_index = First_Index (gnat_entity),
               gnat_base_index
                 = First_Index (Implementation_Base_Type (gnat_entity));
               0 <= index && index < ndim;
               index += (convention_fortran_p ? - 1 : 1),
               gnat_index = Next_Index (gnat_index),
               gnat_base_index = Next_Index (gnat_base_index))
            {
              tree gnu_index_type = get_unpadded_type (Etype (gnat_index));
              const int prec_comp
                = compare_tree_int (TYPE_RM_SIZE (gnu_index_type),
                                    TYPE_PRECISION (sizetype));
              const bool subrange_p = (prec_comp < 0)
                                      || (prec_comp == 0
                                          && TYPE_UNSIGNED (gnu_index_type)
                                             == TYPE_UNSIGNED (sizetype));
              const bool wider_p = (prec_comp > 0);
              tree gnu_orig_min = TYPE_MIN_VALUE (gnu_index_type);
              tree gnu_orig_max = TYPE_MAX_VALUE (gnu_index_type);
              tree gnu_min = convert (sizetype, gnu_orig_min);
              tree gnu_max = convert (sizetype, gnu_orig_max);
              tree gnu_base_index_type
                = get_unpadded_type (Etype (gnat_base_index));
              tree gnu_base_orig_min = TYPE_MIN_VALUE (gnu_base_index_type);
              tree gnu_base_orig_max = TYPE_MAX_VALUE (gnu_base_index_type);
              tree gnu_high, gnu_low;

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

              /* Similarly, if one of the values overflows in sizetype and the
                 range is null, use 1..0 for the sizetype bounds.  */
              else if (!subrange_p
                       && TREE_CODE (gnu_min) == INTEGER_CST
                       && TREE_CODE (gnu_max) == INTEGER_CST
                       && (TREE_OVERFLOW (gnu_min) || TREE_OVERFLOW (gnu_max))
                       && tree_int_cst_lt (gnu_orig_max, gnu_orig_min))
                {
                  gnu_min = size_one_node;
                  gnu_max = size_zero_node;
                  gnu_high = gnu_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 indication.  */
              else if (!subrange_p
                       && TREE_CODE (gnu_min) == INTEGER_CST
                       && TREE_CODE (gnu_max) == INTEGER_CST
                       && TREE_OVERFLOW (gnu_min) && TREE_OVERFLOW (gnu_max)
                       && !TREE_OVERFLOW
                           (convert (sizetype,
                                     fold_build2 (MINUS_EXPR, gnu_index_type,
                                                  gnu_orig_max,
                                                  gnu_orig_min))))
                {
                  TREE_OVERFLOW (gnu_min) = 0;
                  TREE_OVERFLOW (gnu_max) = 0;
                  gnu_high = gnu_max;
                }

              /* Compute the size of this dimension in the general case.  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 type.  */
              else if (Nkind (gnat_index) == N_Range
                       && cannot_be_superflat_p (gnat_index))
                gnu_high = gnu_max;

              /* Otherwise, if we can prove that the low bound minus one and
                 the high bound cannot overflow, we can just use the expression
                 MAX (hb, lb - 1).  Similarly, if we can prove that the high
                 bound plus one and the low bound cannot overflow, we can use
                 the high bound as-is and MIN (hb + 1, lb) for the low bound.
                 Otherwise, we have to fall back to the most general expression
                 (hb >= lb) ? hb : lb - 1.  Note that the comparison must be
                 done in the original index type, to avoid any overflow during
                 the conversion.  */
              else
                {
                  gnu_high = size_binop (MINUS_EXPR, gnu_min, size_one_node);
                  gnu_low = size_binop (PLUS_EXPR, gnu_max, size_one_node);

                  /* If gnu_high is a constant that has overflowed, the low
                     bound is the smallest integer so cannot be the maximum.
                     If gnu_low is a constant that has overflowed, the high
                     bound is the highest integer so cannot be the minimum.  */
                  if ((TREE_CODE (gnu_high) == INTEGER_CST
                       && TREE_OVERFLOW (gnu_high))
                      || (TREE_CODE (gnu_low) == INTEGER_CST
                           && TREE_OVERFLOW (gnu_low)))
                    gnu_high = gnu_max;

                  /* If the index type is a subrange and gnu_high a constant
                     that hasn't overflowed, we can use the maximum.  */
                  else if (subrange_p && TREE_CODE (gnu_high) == INTEGER_CST)
                    gnu_high = size_binop (MAX_EXPR, gnu_max, gnu_high);

                  /* If the index type is a subrange and gnu_low a constant
                     that hasn't overflowed, we can use the minimum.  */
                  else if (subrange_p && TREE_CODE (gnu_low) == INTEGER_CST)
                    {
                      gnu_high = gnu_max;
                      gnu_min = size_binop (MIN_EXPR, gnu_min, gnu_low);
                    }

                  else
                    gnu_high
                      = build_cond_expr (sizetype,
                                         build_binary_op (GE_EXPR,
                                                          integer_type_node,
                                                          gnu_orig_max,
                                                          gnu_orig_min),
                                         gnu_max, gnu_high);
                }

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

              /* Update the maximum size of the array in elements.  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 (gnu_max_size)
                {
                  tree gnu_base_min = convert (sizetype, gnu_base_orig_min);
                  tree gnu_base_max = convert (sizetype, gnu_base_orig_max);
                  tree gnu_base_index_base_type
                    = get_base_type (gnu_base_index_type);
                  tree gnu_base_base_min
                    = convert (sizetype,
                               TYPE_MIN_VALUE (gnu_base_index_base_type));
                  tree gnu_base_base_max
                    = convert (sizetype,
                               TYPE_MAX_VALUE (gnu_base_index_base_type));

                  if (!CONTAINS_PLACEHOLDER_P (gnu_min)
                      || !(TREE_CODE (gnu_base_min) == INTEGER_CST
                           && !TREE_OVERFLOW (gnu_base_min)))
                    gnu_base_min = gnu_min;

                  if (!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))
                    gnu_max_size = NULL_TREE;
                  else
                    {
                      tree 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))
                        gnu_max_size = NULL_TREE;
                      else
                        gnu_max_size
                          = size_binop (MULT_EXPR, gnu_max_size, gnu_this_max);
                    }
                }

              /* We need special types for debugging information to point to
                 the index types if they have variable bounds, are not integer
                 types, are biased or are wider than sizetype.  */
              if (!integer_onep (gnu_orig_min)
                  || TREE_CODE (gnu_orig_max) != INTEGER_CST
                  || TREE_CODE (gnu_index_type) != INTEGER_TYPE
                  || (TREE_TYPE (gnu_index_type)
                      && TREE_CODE (TREE_TYPE (gnu_index_type))
                         != INTEGER_TYPE)
                  || TYPE_BIASED_REPRESENTATION_P (gnu_index_type)
                  || wider_p)
                need_index_type_struct = true;
            }

          /* Then flatten: create the array of arrays.  For an array type
             used to implement a packed array, get the component type from
             the original array type since the representation clauses that
             can affect it are on the latter.  */
          if (Is_Packed_Array_Type (gnat_entity)
              && !Is_Bit_Packed_Array (Original_Array_Type (gnat_entity)))
            {
              gnu_type = gnat_to_gnu_type (Original_Array_Type (gnat_entity));
              for (index = ndim - 1; index >= 0; index--)
                gnu_type = TREE_TYPE (gnu_type);

              /* 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;
                }
            }
          else
            {
              gnu_type = gnat_to_gnu_component_type (gnat_entity, definition,
                                                     debug_info_p);

              /* 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;
                }
            }

          /* Compute the maximum size of the array in units and bits.  */
          if (gnu_max_size)
            {
              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));
            }
          else
            gnu_max_size_unit = NULL_TREE;

          /* Now build the array type.  */
          for (index = ndim - 1; index >= 0; index --)
            {
              gnu_type = build_array_type (gnu_type, gnu_index_types[index]);
              TYPE_MULTI_ARRAY_P (gnu_type) = (index > 0);
              if (array_type_has_nonaliased_component (gnu_type, gnat_entity))
                TYPE_NONALIASED_COMPONENT (gnu_type) = 1;
            }

          /* Attach the TYPE_STUB_DECL in case we have a parallel type.  */
          TYPE_STUB_DECL (gnu_type)
            = create_type_stub_decl (gnu_entity_name, gnu_type);

          /* 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 () && ndim > 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_name (gnu_str_name, "ST"))
                {
                  tree eltype = TREE_TYPE (gnu_arr_type);

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

                  /* ??? 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
                       (build_binary_op (EXACT_DIV_EXPR, sizetype,
                                         TYPE_SIZE_UNIT (gnu_arr_type),
                                         size_int (TYPE_ALIGN (eltype)
                                                   / BITS_PER_UNIT)),
                        gnat_entity, concat_name (gnu_str_name, "A_U"),
                        definition, false),
                       size_int (TYPE_ALIGN (eltype) / BITS_PER_UNIT));

                  /* ??? create_type_decl is not invoked on the inner types so
                     the MULT_EXPR node built above will never be marked.  */
                  MARK_VISITED (TYPE_SIZE_UNIT (gnu_arr_type));
                }
            }

          /* If we need to write out a record type giving the names of the
             bounds for debugging purposes, do it now and make the record
             type a parallel type.  This is not needed for a packed array
             since the bounds are conveyed by the original array type.  */
          if (need_index_type_struct
              && debug_info_p
              && !Is_Packed_Array_Type (gnat_entity))
            {
              tree gnu_bound_rec = make_node (RECORD_TYPE);
              tree gnu_field_list = NULL_TREE;
              tree gnu_field;

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

              for (index = ndim - 1; index >= 0; index--)
                {
                  tree gnu_index = TYPE_INDEX_TYPE (gnu_index_types[index]);
                  tree gnu_index_name = TYPE_NAME (gnu_index);

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

                  /* Make sure to reference the types themselves, and not just
                     their names, as the debugger may fall back on them.  */
                  gnu_field = create_field_decl (gnu_index_name, gnu_index,
                                                 gnu_bound_rec,
                                                 0, NULL_TREE, NULL_TREE, 0);
                  TREE_CHAIN (gnu_field) = gnu_field_list;
                  gnu_field_list = gnu_field;
                }

              finish_record_type (gnu_bound_rec, gnu_field_list, 0, true);
              add_parallel_type (TYPE_STUB_DECL (gnu_type), gnu_bound_rec);
            }

          /* Otherwise, for a packed array, make the original array type a
             parallel type.  */
          else if (debug_info_p
                   && Is_Packed_Array_Type (gnat_entity)
                   && present_gnu_tree (Original_Array_Type (gnat_entity)))
            add_parallel_type (TYPE_STUB_DECL (gnu_type),
                               gnat_to_gnu_type
                               (Original_Array_Type (gnat_entity)));

          TYPE_CONVENTION_FORTRAN_P (gnu_type) = convention_fortran_p;
          TYPE_PACKED_ARRAY_TYPE_P (gnu_type)
            = (Is_Packed_Array_Type (gnat_entity)
               && Is_Bit_Packed_Array (Original_Array_Type (gnat_entity)));

          /* If the size is self-referential and the maximum size doesn't
             overflow, use it.  */
          if (CONTAINS_PLACEHOLDER_P (TYPE_SIZE (gnu_type))
              && gnu_max_size
              && !(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)))
            {
              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.  */
          relate_alias_sets (gnu_type, gnu_base_type, ALIAS_SET_COPY);

          /* 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;

              /* First finish the type we had been making so that we output
                 debugging information for it.  */
              if (Treat_As_Volatile (gnat_entity))
                gnu_type
                  = build_qualified_type (gnu_type,
                                          TYPE_QUALS (gnu_type)
                                          | TYPE_QUAL_VOLATILE);

              /* Make it artificial only if the base type was artificial too.
                 That's sort of "morally" true and will make it possible for
                 the debugger to look it up by name in DWARF, which is needed
                 in order to decode the packed array type.  */
              gnu_decl
                = create_type_decl (gnu_entity_name, gnu_type, attr_list,
                                    !Comes_From_Source (Etype (gnat_entity))
                                    && !Comes_From_Source (gnat_entity),
                                    debug_info_p, gnat_entity);

              /* 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_type = TREE_TYPE (gnu_decl);
              save_gnu_tree (gnat_entity, NULL_TREE, false);

              gnu_inner = gnu_type;
              while (TREE_CODE (gnu_inner) == RECORD_TYPE
                     && (TYPE_JUSTIFIED_MODULAR_P (gnu_inner)
                         || TYPE_PADDING_P (gnu_inner)))
                gnu_inner = TREE_TYPE (TYPE_FIELDS (gnu_inner));

              /* We need to attach the index type to the type we just made so
                 that the actual bounds can later be put into a template.  */
              if ((TREE_CODE (gnu_inner) == ARRAY_TYPE
                   && !TYPE_ACTUAL_BOUNDS (gnu_inner))
                  || (TREE_CODE (gnu_inner) == INTEGER_TYPE
                      && !TYPE_HAS_ACTUAL_BOUNDS_P (gnu_inner)))
                {
                  if (TREE_CODE (gnu_inner) == INTEGER_TYPE)
                    {
                      /* The TYPE_ACTUAL_BOUNDS field is overloaded with the
                         TYPE_MODULUS for modular types so we make an extra
                         subtype if necessary.  */
                      if (TYPE_MODULAR_P (gnu_inner))
                        {
                          tree gnu_subtype
                            = make_unsigned_type (TYPE_PRECISION (gnu_inner));
                          TREE_TYPE (gnu_subtype) = gnu_inner;
                          TYPE_EXTRA_SUBTYPE_P (gnu_subtype) = 1;
                          SET_TYPE_RM_MIN_VALUE (gnu_subtype,
                                                 TYPE_MIN_VALUE (gnu_inner));
                          SET_TYPE_RM_MAX_VALUE (gnu_subtype,
                                                 TYPE_MAX_VALUE (gnu_inner));
                          gnu_inner = gnu_subtype;
                        }

                      TYPE_HAS_ACTUAL_BOUNDS_P (gnu_inner) = 1;

#ifdef ENABLE_CHECKING
                      /* Check for other cases of overloading.  */
                      gcc_assert (!TYPE_ACTUAL_BOUNDS (gnu_inner));
#endif
                    }

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

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

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

          else
            /* Abort if packed array with no Packed_Array_Type field set.  */
            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_index_type
          = create_index_type (convert (sizetype, gnu_lower_bound),
                               convert (sizetype, gnu_upper_bound),
                               create_range_type (gnu_string_index_type,
                                                  gnu_lower_bound,
                                                  gnu_upper_bound),
                               gnat_entity);

        gnu_type
          = build_array_type (gnat_to_gnu_type (Component_Type (gnat_entity)),
                              gnu_index_type);
        if (array_type_has_nonaliased_component (gnu_type, gnat_entity))
          TYPE_NONALIASED_COMPONENT (gnu_type) = 1;
        relate_alias_sets (gnu_type, gnu_string_type, ALIAS_SET_COPY);
      }
      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, gnu_field_list = NULL_TREE, gnu_get_parent;
        /* Set PACKED in keeping with gnat_to_gnu_field.  */
        int packed
          = Is_Packed (gnat_entity)
            ? 1
            : Component_Alignment (gnat_entity) == Calign_Storage_Unit
              ? -1
              : (Known_Alignment (gnat_entity)
                 || (Strict_Alignment (gnat_entity)
                     && Known_Static_Esize (gnat_entity)))
                ? -2
                : 0;
        bool has_discr = Has_Discriminants (gnat_entity);
        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);
        bool is_unchecked_union = Is_Unchecked_Union (gnat_entity);

        /* See if all fields have a rep clause.  Stop when we find one
           that doesn't.  */
        if (all_rep)
          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)
                && No (Component_Clause (gnat_field)))
              {
                all_rep = false;
                break;
              }

        /* 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_name;
        TYPE_PACKED (gnu_type) = (packed != 0) || 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 : ceil_alignment (esize);
        /* If a type needs strict alignment, the minimum size will be the
           type size instead of the RM size (see validate_size).  Cap the
           alignment, lest it causes this type size to become too large.  */
        else if (Strict_Alignment (gnat_entity)
                 && Known_Static_Esize (gnat_entity))
          {
            unsigned int raw_size = UI_To_Int (Esize (gnat_entity));
            unsigned int raw_align = raw_size & -raw_size;
            if (raw_align < BIGGEST_ALIGNMENT)
              TYPE_ALIGN (gnu_type) = raw_align;
          }
        else
          TYPE_ALIGN (gnu_type) = 0;

        /* 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 (input_location,
                                                 FIELD_DECL, NULL_TREE,
                                                 void_type_node),
                                     NULL_TREE);

            if (has_discr)
              for (gnat_field = First_Stored_Discriminant (gnat_entity);
                   Present (gnat_field);
                   gnat_field = Next_Stored_Discriminant (gnat_field))
                if (Present (Corresponding_Discriminant (gnat_field)))
                  {
                    tree gnu_field
                      = gnat_to_gnu_field_decl (Corresponding_Discriminant
                                                (gnat_field));
                    save_gnu_tree
                      (gnat_field,
                       build3 (COMPONENT_REF, TREE_TYPE (gnu_field),
                               gnu_get_parent, gnu_field, NULL_TREE),
                       true);
                  }

            /* Then we build the parent subtype.  If it has discriminants but
               the type itself has unknown discriminants, this means that it
               doesn't contain information about how the discriminants are
               derived from those of the ancestor type, so it cannot be used
               directly.  Instead it is built by cloning the parent subtype
               of the underlying record view of the type, for which the above
               derivation of discriminants has been made explicit.  */
            if (Has_Discriminants (gnat_parent)
                && Has_Unknown_Discriminants (gnat_entity))
              {
                Entity_Id gnat_uview = Underlying_Record_View (gnat_entity);

                /* If we are defining the type, the underlying record
                   view must already have been elaborated at this point.
                   Otherwise do it now as its parent subtype cannot be
                   technically elaborated on its own.  */
                if (definition)
                  gcc_assert (present_gnu_tree (gnat_uview));
                else
                  gnat_to_gnu_entity (gnat_uview, NULL_TREE, 0);

                gnu_parent = gnat_to_gnu_type (Parent_Subtype (gnat_uview));

                /* Substitute the "get to the parent" of the type for that
                   of its underlying record view in the cloned type.  */
                for (gnat_field = First_Stored_Discriminant (gnat_uview);
                     Present (gnat_field);
                     gnat_field = Next_Stored_Discriminant (gnat_field))
                  if (Present (Corresponding_Discriminant (gnat_field)))
                    {
                      tree gnu_field = gnat_to_gnu_field_decl (gnat_field);
                      tree gnu_ref
                        = build3 (COMPONENT_REF, TREE_TYPE (gnu_field),
                                  gnu_get_parent, gnu_field, NULL_TREE);
                      gnu_parent
                        = substitute_in_type (gnu_parent, gnu_field, gnu_ref);
                    }
              }
            else
              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_discr)
              {
                /* The actual parent subtype is the full view.  */
                if (IN (Ekind (gnat_parent), Private_Kind))
                  {
                    if (Present (Full_View (gnat_parent)))
                      gnat_parent = Full_View (gnat_parent);
                    else
                      gnat_parent = Underlying_Full_View (gnat_parent);
                  }

                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
              = create_field_decl (get_identifier
                                   (Get_Name_String (Name_uParent)),
                                   gnu_parent, gnu_type, 0,
                                   has_rep
                                   ? TYPE_SIZE (gnu_parent) : NULL_TREE,
                                   has_rep
                                   ? bitsize_zero_node : NULL_TREE, 1);
            DECL_INTERNAL_P (gnu_field) = 1;
            TREE_OPERAND (gnu_get_parent, 1) = gnu_field;
            TYPE_FIELDS (gnu_type) = gnu_field;
          }

        /* Make the fields for the discriminants and put them into the record
           unless it's an Unchecked_Union.  */
        if (has_discr)
          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 handled it 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,
                                     debug_info_p);

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

              if (!is_unchecked_union)
                {
                  TREE_CHAIN (gnu_field) = gnu_field_list;
                  gnu_field_list = gnu_field;
                }
            }

        /* Add the fields into the record type and finish it up.  */
        components_to_record (gnu_type, Component_List (record_definition),
                              gnu_field_list, packed, definition, NULL,
                              false, all_rep, is_unchecked_union,
                              debug_info_p, false);

        /* If it is a tagged record force the type to BLKmode to insure that
           these objects will always be put in memory.  Likewise for limited
           record types.  */
        if (Is_Tagged_Type (gnat_entity) || Is_Limited_Record (gnat_entity))
          SET_TYPE_MODE (gnu_type, BLKmode);

        /* We used to remove the associations of the discriminants and _Parent
           for validity checking but we may need them if there's a Freeze_Node
           for a subtype used in this record.  */
        TYPE_VOLATILE (gnu_type) = Treat_As_Volatile (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 (gnat_equiv_type != gnat_entity)
        {
          gnu_decl = gnat_to_gnu_entity (gnat_equiv_type, 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;
          break;
        }

      /* 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 the position computed by transforming
         every discriminant reference according to the constraints.  We don't
         see any difference between private and non-private 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;

          if (!definition)
            {
              defer_incomplete_level++;
              this_deferred = true;
            }

          gnu_base_type = gnat_to_gnu_type (gnat_base_type);

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

          /* When the subtype has discriminants and these discriminants affect
             the initial shape it has inherited, factor them in.  But for an
             Unchecked_Union (it must be an Itype), just return the type.
             We can't just test Is_Constrained because private subtypes without
             discriminants of types with discriminants with default expressions
             are Is_Constrained but aren't constrained!  */
          if (IN (Ekind (gnat_base_type), Record_Kind)
              && !Is_Unchecked_Union (gnat_base_type)
              && !Is_For_Access_Subtype (gnat_entity)
              && Is_Constrained (gnat_entity)
              && Has_Discriminants (gnat_entity)
              && Present (Discriminant_Constraint (gnat_entity))
              && Stored_Constraint (gnat_entity) != No_Elist)
            {
              tree gnu_subst_list
                = build_subst_list (gnat_entity, gnat_base_type, definition);
              tree gnu_unpad_base_type, gnu_rep_part, gnu_variant_part, t;
              tree gnu_variant_list, gnu_pos_list, gnu_field_list = NULL_TREE;
              bool selected_variant = false;
              Entity_Id gnat_field;

              gnu_type = make_node (RECORD_TYPE);
              TYPE_NAME (gnu_type) = gnu_entity_name;

              /* Set the size, alignment and alias set of the new type to
                 match that of the old one, doing required substitutions.  */
              copy_and_substitute_in_size (gnu_type, gnu_base_type,
                                           gnu_subst_list);

              if (TYPE_IS_PADDING_P (gnu_base_type))
                gnu_unpad_base_type = TREE_TYPE (TYPE_FIELDS (gnu_base_type));
              else
                gnu_unpad_base_type = gnu_base_type;

              /* Look for a REP part in the base type.  */
              gnu_rep_part = get_rep_part (gnu_unpad_base_type);

              /* Look for a variant part in the base type.  */
              gnu_variant_part = get_variant_part (gnu_unpad_base_type);

              /* If there is a variant part, we must compute whether the
                 constraints statically select a particular variant.  If
                 so, we simply drop the qualified union and flatten the
                 list of fields.  Otherwise we'll build a new qualified
                 union for the variants that are still relevant.  */
              if (gnu_variant_part)
                {
                  gnu_variant_list
                    = build_variant_list (TREE_TYPE (gnu_variant_part),
                                          gnu_subst_list, NULL_TREE);

                  /* If all the qualifiers are unconditionally true, the
                     innermost variant is statically selected.  */
                  selected_variant = true;
                  for (t = gnu_variant_list; t; t = TREE_CHAIN (t))
                    if (!integer_onep (TREE_VEC_ELT (TREE_VALUE (t), 1)))
                      {
                        selected_variant = false;
                        break;
                      }

                  /* Otherwise, create the new variants.  */
                  if (!selected_variant)
                    for (t = gnu_variant_list; t; t = TREE_CHAIN (t))
                      {
                        tree old_variant = TREE_PURPOSE (t);
                        tree new_variant = make_node (RECORD_TYPE);
                        TYPE_NAME (new_variant)
                          = DECL_NAME (TYPE_NAME (old_variant));
                        copy_and_substitute_in_size (new_variant, old_variant,
                                                     gnu_subst_list);
                        TREE_VEC_ELT (TREE_VALUE (t), 2) = new_variant;
                      }
                }
              else
                {
                  gnu_variant_list = NULL_TREE;
                  selected_variant = false;
                }

              gnu_pos_list
                = build_position_list (gnu_unpad_base_type,
                                       gnu_variant_list && !selected_variant,
                                       size_zero_node, bitsize_zero_node,
                                       BIGGEST_ALIGNMENT, NULL_TREE);

              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)
                    && !(Present (Corresponding_Discriminant (gnat_field))
                         && Is_Tagged_Type (gnat_base_type))
                    && Underlying_Type (Scope (Original_Record_Component
                                               (gnat_field)))
                       == gnat_base_type)
                  {
                    Name_Id gnat_name = Chars (gnat_field);
                    Entity_Id gnat_old_field
                      = Original_Record_Component (gnat_field);
                    tree gnu_old_field
                      = gnat_to_gnu_field_decl (gnat_old_field);
                    tree gnu_context = DECL_CONTEXT (gnu_old_field);
                    tree gnu_field, gnu_field_type, gnu_size;
                    tree gnu_cont_type, gnu_last = NULL_TREE;

                    /* If the type is the same, retrieve the GCC type from the
                       old field to take into account possible adjustments.  */
                    if (Etype (gnat_field) == Etype (gnat_old_field))
                      gnu_field_type = TREE_TYPE (gnu_old_field);
                    else
                      gnu_field_type = gnat_to_gnu_type (Etype (gnat_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 (gnat_old_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 the old field was packed and of constant size, we
                       have to get the old size here, as it might differ from
                       what the Etype conveys and the latter might overlap
                       onto the following field.  Try to arrange the type for
                       possible better packing along the way.  */
                    else if (DECL_PACKED (gnu_old_field)
                             && TREE_CODE (DECL_SIZE (gnu_old_field))
                                == INTEGER_CST)
                      {
                        gnu_size = DECL_SIZE (gnu_old_field);
                        if (TREE_CODE (gnu_field_type) == RECORD_TYPE
                            && !TYPE_FAT_POINTER_P (gnu_field_type)
                            && host_integerp (TYPE_SIZE (gnu_field_type), 1))
                          gnu_field_type
                            = make_packable_type (gnu_field_type, true);
                      }

                    else
                      gnu_size = TYPE_SIZE (gnu_field_type);

                    /* If the context of the old field is the base type or its
                       REP part (if any), put the field directly in the new
                       type; otherwise look up the context in the variant list
                       and put the field either in the new type if there is a
                       selected variant or in one of the new variants.  */
                    if (gnu_context == gnu_unpad_base_type
                        || (gnu_rep_part
                            && gnu_context == TREE_TYPE (gnu_rep_part)))
                      gnu_cont_type = gnu_type;
                    else
                      {
                        t = purpose_member (gnu_context, gnu_variant_list);
                        if (t)
                          {
                            if (selected_variant)
                              gnu_cont_type = gnu_type;
                            else
                              gnu_cont_type = TREE_VEC_ELT (TREE_VALUE (t), 2);
                          }
                        else
                          /* The front-end may pass us "ghost" components if
                             it fails to recognize that a constrained subtype
                             is statically constrained.  Discard them.  */
                          continue;
                      }

                    /* Now create the new field modeled on the old one.  */
                    gnu_field
                      = create_field_decl_from (gnu_old_field, gnu_field_type,
                                                gnu_cont_type, gnu_size,
                                                gnu_pos_list, gnu_subst_list);

                    /* Put it in one of the new variants directly.  */
                    if (gnu_cont_type != gnu_type)
                      {
                        TREE_CHAIN (gnu_field) = TYPE_FIELDS (gnu_cont_type);
                        TYPE_FIELDS (gnu_cont_type) = gnu_field;
                      }

                    /* To match the layout crafted in components_to_record,
                       if this is the _Tag or _Parent field, put it before
                       any other fields.  */
                    else if (gnat_name == Name_uTag
                             || gnat_name == Name_uParent)
                      gnu_field_list = chainon (gnu_field_list, gnu_field);

                    /* Similarly, if this is the _Controller field, put
                       it before the other fields except for the _Tag or
                       _Parent field.  */
                    else if (gnat_name == Name_uController && gnu_last)
                      {
                        TREE_CHAIN (gnu_field) = TREE_CHAIN (gnu_last);
                        TREE_CHAIN (gnu_last) = gnu_field;
                      }

                    /* Otherwise, if this is a regular field, put it after
                       the other fields.  */
                    else
                      {
                        TREE_CHAIN (gnu_field) = gnu_field_list;
                        gnu_field_list = gnu_field;
                        if (!gnu_last)
                          gnu_last = gnu_field;
                      }

                    save_gnu_tree (gnat_field, gnu_field, false);
                  }

              /* If there is a variant list and no selected variant, we need
                 to create the nest of variant parts from the old nest.  */
              if (gnu_variant_list && !selected_variant)
                {
                  tree new_variant_part
                    = create_variant_part_from (gnu_variant_part,
                                                gnu_variant_list, gnu_type,
                                                gnu_pos_list, gnu_subst_list);
                  TREE_CHAIN (new_variant_part) = gnu_field_list;
                  gnu_field_list = new_variant_part;
                }

              /* 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);

              /* Do not emit debug info for the type yet since we're going to
                 modify it below.  */
              gnu_field_list = nreverse (gnu_field_list);
              finish_record_type (gnu_type, gnu_field_list, 2, false);

              /* See the E_Record_Type case for the rationale.  */
              if (Is_Tagged_Type (gnat_entity)
                  || Is_Limited_Record (gnat_entity))
                SET_TYPE_MODE (gnu_type, BLKmode);
              else
                compute_record_mode (gnu_type);

              TYPE_VOLATILE (gnu_type) = Treat_As_Volatile (gnat_entity);

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

              /* If debugging information is being written for the type, write
                 a record that shows what we are a subtype of and also make a
                 variable that indicates our size, if still variable.  */
              if (debug_info_p)
                {
                  tree gnu_subtype_marker = make_node (RECORD_TYPE);
                  tree gnu_unpad_base_name = TYPE_NAME (gnu_unpad_base_type);
                  tree gnu_size_unit = TYPE_SIZE_UNIT (gnu_type);

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

                  TYPE_NAME (gnu_subtype_marker)
                    = create_concat_name (gnat_entity, "XVS");
                  finish_record_type (gnu_subtype_marker,
                                      create_field_decl (gnu_unpad_base_name,
                                                         build_reference_type
                                                         (gnu_unpad_base_type),
                                                         gnu_subtype_marker,
                                                         0, NULL_TREE,
                                                         NULL_TREE, 0),
                                      0, true);

                  add_parallel_type (TYPE_STUB_DECL (gnu_type),
                                     gnu_subtype_marker);

                  if (definition
                      && TREE_CODE (gnu_size_unit) != INTEGER_CST
                      && !CONTAINS_PLACEHOLDER_P (gnu_size_unit))
                    create_var_decl (create_concat_name (gnat_entity, "XVZ"),
                                     NULL_TREE, sizetype, gnu_size_unit, false,
                                     false, false, false, NULL, gnat_entity);
                }

              /* Now we can finalize it.  */
              rest_of_record_type_compilation (gnu_type);
            }

          /* Otherwise, go down all the components in the new type and make
             them equivalent to those in the base type.  */
          else
            {
              gnu_type = gnu_base_type;

              for (gnat_temp = First_Entity (gnat_entity);
                   Present (gnat_temp);
                   gnat_temp = Next_Entity (gnat_temp))
                if ((Ekind (gnat_temp) == E_Discr