decl.c (gnat_to_gnu_entity, [...]): Make constant variant of designated type for...

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

/****************************************************************************
 *                                                                          *
 *                         GNAT COMPILER COMPONENTS                         *
 *                                                                          *
 *                                T R A N S                                 *
 *                                                                          *
 *                          C Implementation File                           *
 *                                                                          *
 *                            $Revision$
 *                                                                          *
 *          Copyright (C) 1992-2001, Free Software Foundation, Inc.         *
 *                                                                          *
 * GNAT is free software;  you can  redistribute it  and/or modify it under *
 * terms of the  GNU General Public License as published  by the Free Soft- *
 * ware  Foundation;  either version 2,  or (at your option) any later ver- *
 * sion.  GNAT is distributed in the hope that it will be useful, but WITH- *
 * OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY *
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License *
 * for  more details.  You should have  received  a copy of the GNU General *
 * Public License  distributed with GNAT;  see file COPYING.  If not, write *
 * to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, *
 * MA 02111-1307, USA.                                                      *
 *                                                                          *
 * GNAT was originally developed  by the GNAT team at  New York University. *
 * It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). *
 *                                                                          *
 ****************************************************************************/

#include "config.h"
#include "system.h"
#include "tree.h"
#include "real.h"
#include "flags.h"
#include "rtl.h"
#include "expr.h"
#include "ggc.h"
#include "function.h"
#include "debug.h"
#include "output.h"
#include "ada.h"
#include "types.h"
#include "atree.h"
#include "elists.h"
#include "namet.h"
#include "nlists.h"
#include "snames.h"
#include "stringt.h"
#include "uintp.h"
#include "urealp.h"
#include "fe.h"
#include "sinfo.h"
#include "einfo.h"
#include "ada-tree.h"
#include "gigi.h"

int max_gnat_nodes;
int number_names;
struct Node *Nodes_Ptr;
Node_Id *Next_Node_Ptr;
Node_Id *Prev_Node_Ptr;
struct Elist_Header *Elists_Ptr;
struct Elmt_Item *Elmts_Ptr;
struct String_Entry *Strings_Ptr;
Char_Code *String_Chars_Ptr;
struct List_Header *List_Headers_Ptr;

/* Current filename without path. */
const char *ref_filename;

/* Flag indicating whether file names are discarded in exception messages */
int discard_file_names;

/* If true, then gigi is being called on an analyzed but unexpanded
   tree, and the only purpose of the call is to properly annotate
   types with representation information. */
int type_annotate_only;

/* List of TREE_LIST nodes representing a block stack.  TREE_VALUE
   of each gives the variable used for the setjmp buffer in the current
   block, if any.  TREE_PURPOSE gives the bottom condition for a loop,
   if this block is for a loop.  The latter is only used to save the tree
   over GC.  */
tree gnu_block_stack;

/* List of TREE_LIST nodes representing a stack of exception pointer
   variables.  TREE_VALUE is the VAR_DECL that stores the address of
   the raised exception.  Nonzero means we are in an exception
   handler.  Set to error_mark_node in the zero-cost case.  */
static tree gnu_except_ptr_stack;

/* Map GNAT tree codes to GCC tree codes for simple expressions.  */
static enum tree_code gnu_codes[Number_Node_Kinds];

/* Current node being treated, in case gigi_abort called.  */
Node_Id error_gnat_node;

/* Variable that stores a list of labels to be used as a goto target instead of
   a return in some functions.  See processing for N_Subprogram_Body.  */
static tree gnu_return_label_stack;

static tree tree_transform              PARAMS((Node_Id));
static void elaborate_all_entities      PARAMS((Node_Id));
static void process_freeze_entity       PARAMS((Node_Id));
static void process_inlined_subprograms PARAMS((Node_Id));
static void process_decls               PARAMS((List_Id, List_Id, Node_Id,
                                                int, int));
static tree emit_access_check           PARAMS((tree));
static tree emit_discriminant_check     PARAMS((tree, Node_Id));
static tree emit_range_check            PARAMS((tree, Node_Id));
static tree emit_index_check            PARAMS((tree, tree, tree, tree));
static tree emit_check                  PARAMS((tree, tree));
static tree convert_with_check          PARAMS((Entity_Id, tree,
                                                int, int, int));
static int addressable_p                PARAMS((tree));
static tree assoc_to_constructor        PARAMS((Node_Id, tree));
static tree extract_values              PARAMS((tree, tree));
static tree pos_to_constructor          PARAMS((Node_Id, tree, Entity_Id));
static tree maybe_implicit_deref        PARAMS((tree));
static tree gnat_stabilize_reference_1  PARAMS((tree, int));
static int build_unit_elab              PARAMS((Entity_Id, int, tree));

/* Constants for +0.5 and -0.5 for float-to-integer rounding.  */
static REAL_VALUE_TYPE dconstp5;
static REAL_VALUE_TYPE dconstmp5;
\f
/* This is the main program of the back-end.  It sets up all the table
   structures and then generates code.  */

void
gigi (gnat_root, max_gnat_node, number_name,
      nodes_ptr, next_node_ptr, prev_node_ptr, elists_ptr, elmts_ptr,
      strings_ptr, string_chars_ptr, list_headers_ptr,
      number_units, file_info_ptr,
      standard_integer, standard_long_long_float, standard_exception_type,
      gigi_operating_mode)

     Node_Id gnat_root;
     int max_gnat_node;
     int number_name;

     struct Node *nodes_ptr;
     Node_Id *next_node_ptr;
     Node_Id *prev_node_ptr;
     struct Elist_Header *elists_ptr;
     struct Elmt_Item *elmts_ptr;
     struct String_Entry *strings_ptr;
     Char_Code *string_chars_ptr;
     struct List_Header *list_headers_ptr;
     Int number_units ATTRIBUTE_UNUSED;
     char *file_info_ptr ATTRIBUTE_UNUSED;

     Entity_Id standard_integer;
     Entity_Id standard_long_long_float;
     Entity_Id standard_exception_type;

     Int gigi_operating_mode;
{
  max_gnat_nodes = max_gnat_node;
  number_names = number_name;
  Nodes_Ptr = nodes_ptr - First_Node_Id;
  Next_Node_Ptr = next_node_ptr - First_Node_Id;
  Prev_Node_Ptr = prev_node_ptr - First_Node_Id;
  Elists_Ptr = elists_ptr - First_Elist_Id;
  Elmts_Ptr = elmts_ptr - First_Elmt_Id;
  Strings_Ptr = strings_ptr - First_String_Id;
  String_Chars_Ptr = string_chars_ptr;
  List_Headers_Ptr = list_headers_ptr - First_List_Id;

  type_annotate_only = (gigi_operating_mode == 1);

  /* See if we should discard file names in exception messages.  */
  discard_file_names = (Global_Discard_Names || Debug_Flag_NN);

  if (Nkind (gnat_root) != N_Compilation_Unit)
    gigi_abort (301);

  set_lineno (gnat_root, 0);

  /* Initialize ourselves.  */
  init_gnat_to_gnu ();
  init_dummy_type ();
  init_code_table ();

  /* Enable GNAT stack checking method if needed */
  if (!Stack_Check_Probes_On_Target) 
    set_stack_check_libfunc (gen_rtx (SYMBOL_REF, Pmode, "_gnat_stack_check"));

  /* Save the type we made for integer as the type for Standard.Integer.
     Then make the rest of the standard types.  Note that some of these
     may be subtypes.  */
  save_gnu_tree (Base_Type (standard_integer),
                 TYPE_NAME (integer_type_node), 0);

  ggc_add_tree_root (&gnu_block_stack, 1);
  ggc_add_tree_root (&gnu_except_ptr_stack, 1);
  ggc_add_tree_root (&gnu_return_label_stack, 1);
  gnu_except_ptr_stack = tree_cons (NULL_TREE, NULL_TREE, NULL_TREE);

  dconstp5 = REAL_VALUE_ATOF ("0.5", DFmode);
  dconstmp5 = REAL_VALUE_ATOF ("-0.5", DFmode);

  init_gigi_decls (gnat_to_gnu_entity (Base_Type (standard_long_long_float),
                                       NULL_TREE, 0),
                   gnat_to_gnu_entity (Base_Type (standard_exception_type),
                                       NULL_TREE, 0));

  /* Emit global symbols containing context list info for the SGI Workshop
     debugger */

#ifdef MIPS_DEBUGGING_INFO
  if (Spec_Context_List != 0)
    emit_unit_label (Spec_Context_List, Spec_Filename);

  if (Body_Context_List != 0)
    emit_unit_label (Body_Context_List, Body_Filename);
#endif

#ifdef ASM_OUTPUT_IDENT
  if (Present (Ident_String (Main_Unit)))
    ASM_OUTPUT_IDENT
      (asm_out_file,
       TREE_STRING_POINTER (gnat_to_gnu (Ident_String (Main_Unit))));
#endif

  gnat_to_code (gnat_root);
}

\f
/* This function is the driver of the GNAT to GCC tree transformation process.
   GNAT_NODE is the root of some gnat tree.  It generates code for that
   part of the tree.  */

void
gnat_to_code (gnat_node)
     Node_Id gnat_node;
{
  tree gnu_root;

  /* Save node number in case error */
  error_gnat_node = gnat_node;

  gnu_root = tree_transform (gnat_node);

  /* This should just generate code, not return a value.  If it returns
     a value, something is wrong.  */
  if (gnu_root != error_mark_node)
    gigi_abort (302);
}

/* GNAT_NODE is the root of some GNAT tree.  Return the root of the GCC
   tree corresponding to that GNAT tree.  Normally, no code is generated.
   We just return an equivalent tree which is used elsewhere to generate
   code.  */

tree
gnat_to_gnu (gnat_node)
     Node_Id gnat_node;
{
  tree gnu_root;

  /* Save node number in case error */
  error_gnat_node = gnat_node;

  gnu_root = tree_transform (gnat_node);

  /* If we got no code as a result, something is wrong.  */
  if (gnu_root == error_mark_node && ! type_annotate_only)
    gigi_abort (303);

  return gnu_root;
}
\f
/* This function is the driver of the GNAT to GCC tree transformation process.
   It is the entry point of the tree transformer.  GNAT_NODE is the root of
   some GNAT tree.  Return the root of the corresponding GCC tree or
   error_mark_node to signal that there is no GCC tree to return.

   The latter is the case if only code generation actions have to be performed
   like in the case of if statements, loops, etc.  This routine is wrapped
   in the above two routines for most purposes.  */

static tree
tree_transform (gnat_node)
     Node_Id gnat_node;
{
  tree gnu_result = error_mark_node; /* Default to no value. */
  tree gnu_result_type = void_type_node;
  tree gnu_expr;
  tree gnu_lhs, gnu_rhs;
  Node_Id gnat_temp;
  Entity_Id gnat_temp_type;

  /* Set input_file_name and lineno from the Sloc in the GNAT tree. */
  set_lineno (gnat_node, 0);

  /* If this is a Statement and we are at top level, we add the statement
     as an elaboration for a null tree.  That will cause it to be placed
     in the elaboration procedure.  */
  if (global_bindings_p ()
      && ((IN (Nkind (gnat_node), N_Statement_Other_Than_Procedure_Call)
           && Nkind (gnat_node) != N_Null_Statement)
          || Nkind (gnat_node) == N_Procedure_Call_Statement
          || Nkind (gnat_node) == N_Label
          || (Nkind (gnat_node) == N_Handled_Sequence_Of_Statements
              && (Present (Exception_Handlers (gnat_node))
                  || Present (At_End_Proc (gnat_node))))
          || ((Nkind (gnat_node) == N_Raise_Constraint_Error
               || Nkind (gnat_node) == N_Raise_Storage_Error
               || Nkind (gnat_node) == N_Raise_Program_Error)
              && (Ekind (Etype (gnat_node)) == E_Void))))
    {
      add_pending_elaborations (NULL_TREE, make_transform_expr (gnat_node));

      return error_mark_node;
    }

  /* If this node is a non-static subexpression and we are only
     annotating types, make this into a NULL_EXPR for non-VOID types
     and error_mark_node for void return types.  But allow
     N_Identifier since we use it for lots of things, including
     getting trees for discriminants. */

  if (type_annotate_only
      && IN (Nkind (gnat_node), N_Subexpr)
      && Nkind (gnat_node) != N_Identifier
      && ! Compile_Time_Known_Value (gnat_node))
    {
      gnu_result_type = get_unpadded_type (Etype (gnat_node));

      if (TREE_CODE (gnu_result_type) == VOID_TYPE)
        return error_mark_node;
      else
        return build1 (NULL_EXPR, gnu_result_type,
                       build_call_raise (raise_constraint_error_decl));
    }

  switch (Nkind (gnat_node))
    {
      /********************************/
      /* Chapter 2: Lexical Elements: */
      /********************************/

    case N_Identifier:
    case N_Expanded_Name:
    case N_Operator_Symbol:
    case N_Defining_Identifier:

      /* If the Etype of this node does not equal the Etype of the
         Entity, something is wrong with the entity map, probably in
         generic instantiation. However, this does not apply to
         types. Since we sometime have strange Ekind's, just do
         this test for objects. Also, if the Etype of the Entity
         is private, the Etype of the N_Identifier is allowed to be the
         full type and also we consider a packed array type to be the
         same as the original type. Finally, if the types are Itypes,
         one may be a copy of the other, which is also legal. */

      gnat_temp = (Nkind (gnat_node) == N_Defining_Identifier
                   ? gnat_node : Entity (gnat_node));
      gnat_temp_type = Etype (gnat_temp);

      if (Etype (gnat_node) != gnat_temp_type
          && ! (Is_Packed (gnat_temp_type)
                && Etype (gnat_node) == Packed_Array_Type (gnat_temp_type))
          && ! (IN (Ekind (gnat_temp_type), Private_Kind)
                && Present (Full_View (gnat_temp_type))
                && ((Etype (gnat_node) == Full_View (gnat_temp_type))
                    || (Is_Packed (Full_View (gnat_temp_type))
                        && Etype (gnat_node) ==
                             Packed_Array_Type (Full_View (gnat_temp_type)))))
          && (!Is_Itype (Etype (gnat_node)) || !Is_Itype (gnat_temp_type))
          && (Ekind (gnat_temp) == E_Variable
              || Ekind (gnat_temp) == E_Component
              || Ekind (gnat_temp) == E_Constant
              || Ekind (gnat_temp) == E_Loop_Parameter
              || IN (Ekind (gnat_temp), Formal_Kind)))
        gigi_abort (304);

      /* If this is a reference to a deferred constant whose partial view
         is an unconstrained private type, the proper type is on the full
         view of the constant, not on the full view of the type, which may
         be unconstrained.

         This may be a reference to a type, for example in the prefix of the
         attribute Position, generated for dispatching code (see Make_DT in
         exp_disp,adb). In that case we need the type itself, not is parent,
         in particular if it is a derived type  */

      if (Is_Private_Type (gnat_temp_type)
          && Has_Unknown_Discriminants (gnat_temp_type)
          && Present (Full_View (gnat_temp))
          && ! Is_Type (gnat_temp))
        {
          gnat_temp = Full_View (gnat_temp);
          gnat_temp_type = Etype (gnat_temp);
          gnu_result_type = get_unpadded_type (gnat_temp_type);
        }
      else
        {
          /* Expand the type of this identitier first, in case it is
             an enumeral literal, which only get made when the type
             is expanded.  There is no order-of-elaboration issue here.
             We want to use the Actual_Subtype if it has already been
             elaborated, otherwise the Etype.  Avoid using Actual_Subtype
             for packed arrays to simplify things.  */
          if ((Ekind (gnat_temp) == E_Constant
               || Ekind (gnat_temp) == E_Variable || Is_Formal (gnat_temp))
              && ! (Is_Array_Type (Etype (gnat_temp))
                    && Present (Packed_Array_Type (Etype (gnat_temp))))
              && Present (Actual_Subtype (gnat_temp))
              && present_gnu_tree (Actual_Subtype (gnat_temp)))
            gnat_temp_type = Actual_Subtype (gnat_temp);
          else
            gnat_temp_type = Etype (gnat_node);

          gnu_result_type = get_unpadded_type (gnat_temp_type);
        }

      gnu_result = gnat_to_gnu_entity (gnat_temp, NULL_TREE, 0);

      /* If we are in an exception handler, force this variable into memory
         to ensure optimization does not remove stores that appear
         redundant but are actually needed in case an exception occurs.

         ??? Note that we need not do this if the variable is declared within
         the handler, only if it is referenced in the handler and declared
         in an enclosing block, but we have no way of testing that
         right now.  */
      if (TREE_VALUE (gnu_except_ptr_stack) != 0)
        {
          mark_addressable (gnu_result);
          flush_addressof (gnu_result);
        }

      /* Some objects (such as parameters passed by reference, globals of
         variable size, and renamed objects) actually represent the address
         of the object.  In that case, we must do the dereference.  Likewise,
         deal with parameters to foreign convention subprograms.  Call fold
         here since GNU_RESULT may be a CONST_DECL.  */
      if (DECL_P (gnu_result)
          && (DECL_BY_REF_P (gnu_result)
              || DECL_BY_COMPONENT_PTR_P (gnu_result)))
        {
          int ro = DECL_POINTS_TO_READONLY_P (gnu_result);

          if (DECL_BY_COMPONENT_PTR_P (gnu_result))
            gnu_result = convert (build_pointer_type (gnu_result_type),
                                  gnu_result);

          gnu_result = build_unary_op (INDIRECT_REF, NULL_TREE,
                                       fold (gnu_result));
          TREE_READONLY (gnu_result) = TREE_STATIC (gnu_result) = ro;
        }

      /* The GNAT tree has the type of a function as the type of its result.
         Also use the type of the result if the Etype is a subtype which
         is nominally unconstrained.  But remove any padding from the
         resulting type.  */
      if (TREE_CODE (TREE_TYPE (gnu_result)) == FUNCTION_TYPE
          || Is_Constr_Subt_For_UN_Aliased (gnat_temp_type))
        {
          gnu_result_type = TREE_TYPE (gnu_result);
          if (TREE_CODE (gnu_result_type) == RECORD_TYPE
              && TYPE_IS_PADDING_P (gnu_result_type))
            gnu_result_type = TREE_TYPE (TYPE_FIELDS (gnu_result_type));
        }

      /* We always want to return the underlying INTEGER_CST for an
         enumeration literal to avoid the need to call fold in lots
         of places.  But don't do this is the parent will be taking
         the address of this object.  */
      if (TREE_CODE (gnu_result) == CONST_DECL)
        {
          gnat_temp = Parent (gnat_node);
          if (DECL_CONST_CORRESPONDING_VAR (gnu_result) == 0
              || (Nkind (gnat_temp) != N_Reference
                  && ! (Nkind (gnat_temp) == N_Attribute_Reference
                        && ((Get_Attribute_Id (Attribute_Name (gnat_temp))
                             == Attr_Address)
                            || (Get_Attribute_Id (Attribute_Name (gnat_temp))
                                == Attr_Access)
                            || (Get_Attribute_Id (Attribute_Name (gnat_temp))
                                == Attr_Unchecked_Access)
                            || (Get_Attribute_Id (Attribute_Name (gnat_temp))
                                == Attr_Unrestricted_Access)))))
            gnu_result = DECL_INITIAL (gnu_result);
        }
      break;

    case N_Integer_Literal:
      {
        tree gnu_type;

        /* Get the type of the result, looking inside any padding and
           left-justified modular types.  Then get the value in that type.  */
        gnu_type = gnu_result_type = get_unpadded_type (Etype (gnat_node));

        if (TREE_CODE (gnu_type) == RECORD_TYPE
            && TYPE_LEFT_JUSTIFIED_MODULAR_P (gnu_type))
          gnu_type = TREE_TYPE (TYPE_FIELDS (gnu_type));

        gnu_result = UI_To_gnu (Intval (gnat_node), gnu_type);
        /* Get the type of the result, looking inside any padding and
           left-justified modular types.  Then get the value in that type.  */
        gnu_type = gnu_result_type = get_unpadded_type (Etype (gnat_node));

        if (TREE_CODE (gnu_type) == RECORD_TYPE
            && TYPE_LEFT_JUSTIFIED_MODULAR_P (gnu_type))
          gnu_type = TREE_TYPE (TYPE_FIELDS (gnu_type));

        gnu_result = UI_To_gnu (Intval (gnat_node), gnu_type);

        /* If the result overflows (meaning it doesn't fit in its base type)
           or is outside of the range of the subtype, we have an illegal tree
           entry, so abort.  Note that the test for of types with biased
           representation is harder, so we don't test in that case.  */
        if (TREE_CONSTANT_OVERFLOW (gnu_result)
            || (TREE_CODE (TYPE_MIN_VALUE (gnu_result_type)) == INTEGER_CST
                && ! TYPE_BIASED_REPRESENTATION_P (gnu_result_type)
                && tree_int_cst_lt (gnu_result,
                                    TYPE_MIN_VALUE (gnu_result_type)))
            || (TREE_CODE (TYPE_MAX_VALUE (gnu_result_type)) == INTEGER_CST
                && ! TYPE_BIASED_REPRESENTATION_P (gnu_result_type)
                && tree_int_cst_lt (TYPE_MAX_VALUE (gnu_result_type),
                                    gnu_result)))
          gigi_abort (305);
      }
      break;

    case N_Character_Literal:
      /* If a Entity is present, it means that this was one of the
         literals in a user-defined character type.  In that case,
         just return the value in the CONST_DECL.  Otherwise, use the
         character code.  In that case, the base type should be an
         INTEGER_TYPE, but we won't bother checking for that.  */
      gnu_result_type = get_unpadded_type (Etype (gnat_node));
      if (Present (Entity (gnat_node)))
        gnu_result = DECL_INITIAL (get_gnu_tree (Entity (gnat_node)));
      else
        gnu_result = convert (gnu_result_type,
                              build_int_2 (Char_Literal_Value (gnat_node), 0));
      break;

    case N_Real_Literal:
      /* If this is of a fixed-point type, the value we want is the
         value of the corresponding integer.  */
      if (IN (Ekind (Underlying_Type (Etype (gnat_node))), Fixed_Point_Kind))
        {
          gnu_result_type = get_unpadded_type (Etype (gnat_node));
          gnu_result = UI_To_gnu (Corresponding_Integer_Value (gnat_node),
                                  gnu_result_type);
          if (TREE_CONSTANT_OVERFLOW (gnu_result)
#if 0
              || (TREE_CODE (TYPE_MIN_VALUE (gnu_result_type)) == INTEGER_CST
                  && tree_int_cst_lt (gnu_result,
                                      TYPE_MIN_VALUE (gnu_result_type)))
              || (TREE_CODE (TYPE_MAX_VALUE (gnu_result_type)) == INTEGER_CST
                  && tree_int_cst_lt (TYPE_MAX_VALUE (gnu_result_type),
                                      gnu_result))
#endif
              )
            gigi_abort (305);
        }
      /* We should never see a Vax_Float type literal, since the front end
         is supposed to transform these using appropriate conversions */
      else if (Vax_Float (Underlying_Type (Etype (gnat_node))))
        gigi_abort (334);

      else
        {
          Ureal ur_realval = Realval (gnat_node);

          gnu_result_type = get_unpadded_type (Etype (gnat_node));

          /* If the real value is zero, so is the result.  Otherwise,
             convert it to a machine number if it isn't already.  That
             forces BASE to 0 or 2 and simplifies the rest of our logic.  */
          if (UR_Is_Zero (ur_realval))
            gnu_result = convert (gnu_result_type, integer_zero_node);
          else
            {
              if (! Is_Machine_Number (gnat_node))
                ur_realval =
                   Machine (Base_Type (Underlying_Type (Etype (gnat_node))),
                                      ur_realval);

              gnu_result
                = UI_To_gnu (Numerator (ur_realval), gnu_result_type);

              /* If we have a base of zero, divide by the denominator.
                 Otherwise, the base must be 2 and we scale the value, which
                 we know can fit in the mantissa of the type (hence the use
                 of that type above).  */
              if (Rbase (ur_realval) == 0)
                gnu_result
                  = build_binary_op (RDIV_EXPR,
                                     get_base_type (gnu_result_type),
                                     gnu_result,
                                     UI_To_gnu (Denominator (ur_realval),
                                                gnu_result_type));
              else if (Rbase (ur_realval) != 2)
                gigi_abort (336);

              else
                gnu_result
                  = build_real (gnu_result_type,
                                REAL_VALUE_LDEXP
                                (TREE_REAL_CST (gnu_result),
                                 - UI_To_Int (Denominator (ur_realval))));
            }

          /* Now see if we need to negate the result.  Do it this way to
             properly handle -0.  */
          if (UR_Is_Negative (Realval (gnat_node)))
            gnu_result
              = build_unary_op (NEGATE_EXPR, get_base_type (gnu_result_type),
                                gnu_result);
        }

      break;

    case N_String_Literal:
      gnu_result_type = get_unpadded_type (Etype (gnat_node));
      if (TYPE_PRECISION (TREE_TYPE (gnu_result_type)) == HOST_BITS_PER_CHAR)
        {
          /* We assume here that all strings are of type standard.string.
             "Weird" types of string have been converted to an aggregate
             by the expander. */
          String_Id gnat_string = Strval (gnat_node);
          int length = String_Length (gnat_string);
          char *string = (char *) alloca (length + 1);
          int i;

          /* Build the string with the characters in the literal.  Note
             that Ada strings are 1-origin.  */
          for (i = 0; i < length; i++)
            string[i] = Get_String_Char (gnat_string, i + 1);

          /* Put a null at the end of the string in case it's in a context
             where GCC will want to treat it as a C string.  */
          string[i] = 0;

          gnu_result = build_string (length, string);

          /* Strings in GCC don't normally have types, but we want
             this to not be converted to the array type.  */
          TREE_TYPE (gnu_result) = gnu_result_type;
        }
      else
        {
          /* Build a list consisting of each character, then make
             the aggregate.  */
          String_Id gnat_string = Strval (gnat_node);
          int length = String_Length (gnat_string);
          int i;
          tree gnu_list = NULL_TREE;

          for (i = 0; i < length; i++)
            gnu_list
              = tree_cons (NULL_TREE,
                           convert (TREE_TYPE (gnu_result_type),
                                    build_int_2 (Get_String_Char (gnat_string,
                                                                  i + 1),
                                                 0)),
                           gnu_list);

          gnu_result
            = build_constructor (gnu_result_type, nreverse (gnu_list));
        }
      break;

    case N_Pragma:
      if (type_annotate_only)
        break;

      /* Check for (and ignore) unrecognized pragma */
      if (! Is_Pragma_Name (Chars (gnat_node)))
        break;

      switch (Get_Pragma_Id (Chars (gnat_node)))
        {
        case Pragma_Inspection_Point:
          /* Do nothing at top level: all such variables are already
             viewable.  */
          if (global_bindings_p ())
            break;

          set_lineno (gnat_node, 1);
          for (gnat_temp = First (Pragma_Argument_Associations (gnat_node));
               Present (gnat_temp);
               gnat_temp = Next (gnat_temp))
            {
              gnu_expr = gnat_to_gnu (Expression (gnat_temp));
              if (TREE_CODE (gnu_expr) == UNCONSTRAINED_ARRAY_REF)
                gnu_expr = TREE_OPERAND (gnu_expr, 0);

              gnu_expr = build1 (USE_EXPR, void_type_node, gnu_expr);
              TREE_SIDE_EFFECTS (gnu_expr) = 1;
              expand_expr_stmt (gnu_expr);
            }
          break;

        case Pragma_Optimize:
          switch (Chars (Expression
                         (First (Pragma_Argument_Associations (gnat_node)))))
            {
            case Name_Time:  case Name_Space:
              if (optimize == 0)
                post_error ("insufficient -O value?", gnat_node);
              break;

            case Name_Off:
              if (optimize != 0)
                post_error ("must specify -O0?", gnat_node);
              break;

            default:
              gigi_abort (331);
              break;
            }
          break;

        case Pragma_Reviewable:
          if (write_symbols == NO_DEBUG)
            post_error ("must specify -g?", gnat_node);
          break;
        }
      break;

    /**************************************/
    /* Chapter 3: Declarations and Types: */
    /**************************************/

    case N_Subtype_Declaration:
    case N_Full_Type_Declaration:
    case N_Incomplete_Type_Declaration:
    case N_Private_Type_Declaration:
    case N_Private_Extension_Declaration:
    case N_Task_Type_Declaration:
      process_type (Defining_Entity (gnat_node));
      break;

    case N_Object_Declaration:
    case N_Exception_Declaration:
      gnat_temp = Defining_Entity (gnat_node);

      /* If we are just annotating types and this object has an unconstrained
         or task type, don't elaborate it.   */
      if (type_annotate_only
          && (((Is_Array_Type (Etype (gnat_temp))
                || Is_Record_Type (Etype (gnat_temp)))
               && ! Is_Constrained (Etype (gnat_temp)))
            || Is_Concurrent_Type (Etype (gnat_temp))))
        break;

      if (Present (Expression (gnat_node)) 
          && ! (Nkind (gnat_node) == N_Object_Declaration 
                && No_Initialization (gnat_node))
          && (! type_annotate_only
              || Compile_Time_Known_Value (Expression (gnat_node))))
        {
          gnu_expr = gnat_to_gnu (Expression (gnat_node));
          if (Do_Range_Check (Expression (gnat_node)))
            gnu_expr = emit_range_check (gnu_expr, Etype (gnat_temp));

          /* If this object has its elaboration delayed, we must force
             evaluation of GNU_EXPR right now and save it for when the object
             is frozen.  */
          if (Present (Freeze_Node (gnat_temp)))
            {
              if ((Is_Public (gnat_temp) || global_bindings_p ())
                  && ! TREE_CONSTANT (gnu_expr))
                gnu_expr
                  = create_var_decl (create_concat_name (gnat_temp, "init"),
                                     NULL_TREE, TREE_TYPE (gnu_expr), gnu_expr,
                                     0, Is_Public (gnat_temp), 0, 0, 0);
              else
                gnu_expr = maybe_variable (gnu_expr, Expression (gnat_node));

              save_gnu_tree (gnat_node, gnu_expr, 1);
            }
        }
      else
        gnu_expr = 0;

      if (type_annotate_only && gnu_expr != 0
          && TREE_CODE (gnu_expr) == ERROR_MARK)
        gnu_expr = 0;

      if (No (Freeze_Node (gnat_temp)))
        gnat_to_gnu_entity (gnat_temp, gnu_expr, 1);
      break;

    case N_Object_Renaming_Declaration:

      gnat_temp = Defining_Entity (gnat_node);

      /* Don't do anything if this renaming handled by the front end.
         or if we are just annotating types and this object has an
         unconstrained or task type, don't elaborate it.  */
      if (! Is_Renaming_Of_Object (gnat_temp)
          && ! (type_annotate_only
                && (((Is_Array_Type (Etype (gnat_temp))
                      || Is_Record_Type (Etype (gnat_temp)))
                     && ! Is_Constrained (Etype (gnat_temp)))
                    || Is_Concurrent_Type (Etype (gnat_temp)))))
        {
          gnu_expr = gnat_to_gnu (Renamed_Object (gnat_temp));
          gnat_to_gnu_entity (gnat_temp, gnu_expr, 1);
        }
      break;

    case N_Implicit_Label_Declaration:
      gnat_to_gnu_entity (Defining_Entity (gnat_node), NULL_TREE, 1);
      break;

    case N_Subprogram_Renaming_Declaration:
    case N_Package_Renaming_Declaration:
    case N_Exception_Renaming_Declaration:
    case N_Number_Declaration:
      /* These are fully handled in the front end.  */
      break;

    /*************************************/
    /* Chapter 4: Names and Expressions: */
    /*************************************/

    case N_Explicit_Dereference:
      gnu_result = gnat_to_gnu (Prefix (gnat_node));
      gnu_result_type = get_unpadded_type (Etype (gnat_node));

      /* Emit access check if necessary */
      if (Do_Access_Check (gnat_node))
        gnu_result = emit_access_check (gnu_result);

      gnu_result = build_unary_op (INDIRECT_REF, NULL_TREE, gnu_result);
      break;

    case N_Indexed_Component:
      {
        tree gnu_array_object = gnat_to_gnu (Prefix (gnat_node));
        tree gnu_type;
        int ndim;
        int i;
        Node_Id *gnat_expr_array;

        /* Emit access check if necessary */
        if (Do_Access_Check (gnat_node))
          gnu_array_object = emit_access_check (gnu_array_object);

        gnu_array_object = maybe_implicit_deref (gnu_array_object);
        gnu_array_object = maybe_unconstrained_array (gnu_array_object);

        /* If we got a padded type, remove it too.  */
        if (TREE_CODE (TREE_TYPE (gnu_array_object)) == RECORD_TYPE
            && TYPE_IS_PADDING_P (TREE_TYPE (gnu_array_object)))
          gnu_array_object
            = convert (TREE_TYPE (TYPE_FIELDS (TREE_TYPE (gnu_array_object))), 
                       gnu_array_object);

        gnu_result = gnu_array_object;

        /* First compute the number of dimensions of the array, then
           fill the expression array, the order depending on whether
           this is a Convention_Fortran array or not.  */
        for (ndim = 1, gnu_type = TREE_TYPE (gnu_array_object);
             TREE_CODE (TREE_TYPE (gnu_type)) == ARRAY_TYPE
             && TYPE_MULTI_ARRAY_P (TREE_TYPE (gnu_type));
             ndim++, gnu_type = TREE_TYPE (gnu_type))
          ;

        gnat_expr_array = (Node_Id *) alloca (ndim * sizeof (Node_Id));

        if (TYPE_CONVENTION_FORTRAN_P (TREE_TYPE (gnu_array_object)))
          for (i = ndim - 1, gnat_temp = First (Expressions (gnat_node));
               i >= 0;
               i--, gnat_temp = Next (gnat_temp))
            gnat_expr_array[i] = gnat_temp;
        else
          for (i = 0, gnat_temp = First (Expressions (gnat_node));
               i < ndim;
               i++, gnat_temp = Next (gnat_temp))
            gnat_expr_array[i] = gnat_temp;

        for (i = 0, gnu_type = TREE_TYPE (gnu_array_object);
             i < ndim; i++, gnu_type = TREE_TYPE (gnu_type))
          {
            if (TREE_CODE (gnu_type) != ARRAY_TYPE)
              gigi_abort (307);

            gnat_temp = gnat_expr_array[i];
            gnu_expr = gnat_to_gnu (gnat_temp);

            if (Do_Range_Check (gnat_temp))
              gnu_expr
                = emit_index_check
                  (gnu_array_object, gnu_expr,
                   TYPE_MIN_VALUE (TYPE_INDEX_TYPE (TYPE_DOMAIN (gnu_type))),
                   TYPE_MAX_VALUE (TYPE_INDEX_TYPE (TYPE_DOMAIN (gnu_type))));

            gnu_result = build_binary_op (ARRAY_REF, NULL_TREE,
                                          gnu_result, gnu_expr);
          }
      }

      gnu_result_type = get_unpadded_type (Etype (gnat_node));
      break;

    case N_Slice:
      {
        tree gnu_type;
        Node_Id gnat_range_node = Discrete_Range (gnat_node);

        gnu_result = gnat_to_gnu (Prefix (gnat_node));
        gnu_result_type = get_unpadded_type (Etype (gnat_node));

        /* Emit access check if necessary */
        if (Do_Access_Check (gnat_node))
          gnu_result = emit_access_check (gnu_result);

        /* Do any implicit dereferences of the prefix and do any needed
           range check.  */
        gnu_result = maybe_implicit_deref (gnu_result);
        gnu_result = maybe_unconstrained_array (gnu_result);
        gnu_type = TREE_TYPE (gnu_result);
        if (Do_Range_Check (gnat_range_node)) 
          {
            /* Get the bounds of the slice. */
            tree gnu_index_type
              = TYPE_INDEX_TYPE (TYPE_DOMAIN (gnu_result_type));
            tree gnu_min_expr = TYPE_MIN_VALUE (gnu_index_type);
            tree gnu_max_expr = TYPE_MAX_VALUE (gnu_index_type);
            tree gnu_expr_l, gnu_expr_h, gnu_expr_type;

            /* Check to see that the minimum slice value is in range */
            gnu_expr_l
              = emit_index_check
                (gnu_result, gnu_min_expr,
                 TYPE_MIN_VALUE (TYPE_INDEX_TYPE (TYPE_DOMAIN (gnu_type))),
                 TYPE_MAX_VALUE (TYPE_INDEX_TYPE (TYPE_DOMAIN (gnu_type))));

            /* Check to see that the maximum slice value is in range */
            gnu_expr_h
              = emit_index_check
                (gnu_result, gnu_max_expr,
                 TYPE_MIN_VALUE (TYPE_INDEX_TYPE (TYPE_DOMAIN (gnu_type))),
                 TYPE_MAX_VALUE (TYPE_INDEX_TYPE (TYPE_DOMAIN (gnu_type))));

            /* Derive a good type to convert everything too */
            gnu_expr_type = get_base_type (TREE_TYPE (gnu_expr_l));

            /* Build a compound expression that does the range checks */
            gnu_expr
              = build_binary_op (COMPOUND_EXPR, gnu_expr_type,
                                 convert (gnu_expr_type, gnu_expr_h),
                                 convert (gnu_expr_type, gnu_expr_l));

            /* Build a conditional expression that returns the range checks
               expression if the slice range is not null (max >= min) or
               returns the min if the slice range is null */
            gnu_expr
              = fold (build (COND_EXPR, gnu_expr_type,
                             build_binary_op (GE_EXPR, gnu_expr_type,
                                              convert (gnu_expr_type,
                                                       gnu_max_expr),
                                              convert (gnu_expr_type,
                                                       gnu_min_expr)),
                             gnu_expr, gnu_min_expr));
          }
        else
          gnu_expr = TYPE_MIN_VALUE (TYPE_DOMAIN (gnu_result_type));

        gnu_result = build_binary_op (ARRAY_RANGE_REF, gnu_result_type,
                                      gnu_result, gnu_expr);
      }
      break;

    case N_Selected_Component:
      {
        tree gnu_prefix = gnat_to_gnu (Prefix (gnat_node));
        Entity_Id gnat_field = Entity (Selector_Name (gnat_node));
        Entity_Id gnat_pref_type = Etype (Prefix (gnat_node));
        tree gnu_field;

        while (IN (Ekind (gnat_pref_type), Incomplete_Or_Private_Kind)
               || IN (Ekind (gnat_pref_type), Access_Kind))
          {
            if (IN (Ekind (gnat_pref_type), Incomplete_Or_Private_Kind)) 
              gnat_pref_type = Underlying_Type (gnat_pref_type);
            else if (IN (Ekind (gnat_pref_type), Access_Kind))
              gnat_pref_type = Designated_Type (gnat_pref_type);
          }

        if (Do_Access_Check (gnat_node))
          gnu_prefix = emit_access_check (gnu_prefix);

        gnu_prefix = maybe_implicit_deref (gnu_prefix);

        /* For discriminant references in tagged types always substitute the
           corresponding discriminant as the actual selected component. */

        if (Is_Tagged_Type (gnat_pref_type))
          while (Present (Corresponding_Discriminant (gnat_field)))
            gnat_field = Corresponding_Discriminant (gnat_field);

        /* For discriminant references of untagged types always substitute the
           corresponding girder discriminant. */

        else if (Present (Corresponding_Discriminant (gnat_field)))
          gnat_field = Original_Record_Component (gnat_field);

        /* Handle extracting the real or imaginary part of a complex.
           The real part is the first field and the imaginary the last.  */

        if (TREE_CODE (TREE_TYPE (gnu_prefix)) == COMPLEX_TYPE)
          gnu_result = build_unary_op (Present (Next_Entity (gnat_field))
                                       ? REALPART_EXPR : IMAGPART_EXPR,
                                       NULL_TREE, gnu_prefix);
        else
          {
            gnu_field = gnat_to_gnu_entity (gnat_field, NULL_TREE, 0);

            /* If there are discriminants, the prefix might be
               evaluated more than once, which is a problem if it has
               side-effects. */

            if (Has_Discriminants (Is_Access_Type (Etype (Prefix (gnat_node)))
                                   ? Designated_Type (Etype
                                                      (Prefix (gnat_node)))
                                   : Etype (Prefix (gnat_node)))
                && TREE_SIDE_EFFECTS (gnu_prefix))
              gnu_prefix = make_save_expr (gnu_prefix);

            /* Emit discriminant check if necessary.  */
            if (Do_Discriminant_Check (gnat_node))
              gnu_prefix = emit_discriminant_check (gnu_prefix, gnat_node);
            gnu_result
              = build_component_ref (gnu_prefix, NULL_TREE, gnu_field);
          }

        if (gnu_result == 0)
          gigi_abort (308);

        gnu_result_type = get_unpadded_type (Etype (gnat_node));
      }
      break;

    case N_Attribute_Reference:
      {
        /* The attribute designator (like an enumeration value). */
        int attribute = Get_Attribute_Id (Attribute_Name (gnat_node));
        int prefix_unused = 0;
        tree gnu_prefix;
        tree gnu_type;

        /* The Elab_Spec and Elab_Body attributes are special in that
           Prefix is a unit, not an object with a GCC equivalent.  Similarly
           for Elaborated, since that variable isn't otherwise known.  */
        if (attribute == Attr_Elab_Body || attribute == Attr_Elab_Spec)
          {
            gnu_prefix
              = create_subprog_decl
                (create_concat_name (Entity (Prefix (gnat_node)),
                                     attribute == Attr_Elab_Body
                                     ? "elabb" : "elabs"),
                 NULL_TREE, void_ftype, NULL_TREE, 0, 1, 1, 0);
            return gnu_prefix;
          }

        gnu_prefix = gnat_to_gnu (Prefix (gnat_node));
        gnu_type = TREE_TYPE (gnu_prefix);

        /* If the input is a NULL_EXPR, make a new one.  */
        if (TREE_CODE (gnu_prefix) == NULL_EXPR)
          {
            gnu_result_type = get_unpadded_type (Etype (gnat_node));
            gnu_result = build1 (NULL_EXPR, gnu_result_type,
                                 TREE_OPERAND (gnu_prefix, 0));
            break;
          }

        switch (attribute)
          {
          case Attr_Pos:
          case Attr_Val:
            /* These are just conversions until since representation
               clauses for enumerations are handled in the front end.  */
            {
              int check_p = Do_Range_Check (First (Expressions (gnat_node)));

              gnu_result = gnat_to_gnu (First (Expressions (gnat_node)));
              gnu_result_type = get_unpadded_type (Etype (gnat_node));
              gnu_result = convert_with_check (Etype (gnat_node), gnu_result,
                                               check_p, check_p, 1);
            }
            break;

          case Attr_Pred:
          case Attr_Succ:
            /* These just add or subject the constant 1.  Representation
               clauses for enumerations are handled in the front-end.  */
            gnu_expr = gnat_to_gnu (First (Expressions (gnat_node)));
            gnu_result_type = get_unpadded_type (Etype (gnat_node));

            if (Do_Range_Check (First (Expressions (gnat_node))))
              {
                gnu_expr = make_save_expr (gnu_expr);
                gnu_expr
                  = emit_check
                    (build_binary_op (EQ_EXPR, integer_type_node,
                                      gnu_expr,
                                      attribute == Attr_Pred
                                      ? TYPE_MIN_VALUE (gnu_result_type)
                                      : TYPE_MAX_VALUE (gnu_result_type)),
                     gnu_expr);
              }

            gnu_result
              = build_binary_op (attribute == Attr_Pred
                                 ? MINUS_EXPR : PLUS_EXPR,
                                 gnu_result_type, gnu_expr,
                                 convert (gnu_result_type, integer_one_node));
            break;

          case Attr_Address:
          case Attr_Unrestricted_Access:

            /* Conversions don't change something's address but can cause
               us to miss the COMPONENT_REF case below, so strip them off.  */
            gnu_prefix = remove_conversions (gnu_prefix);

            /* If we are taking 'Address of an unconstrained object,
               this is the pointer to the underlying array.  */
            gnu_prefix = maybe_unconstrained_array (gnu_prefix);

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

          case Attr_Access:
          case Attr_Unchecked_Access:
          case Attr_Code_Address:

            gnu_result_type = get_unpadded_type (Etype (gnat_node));
            gnu_result
              = build_unary_op (attribute == Attr_Address
                                || attribute == Attr_Unrestricted_Access
                                ? ATTR_ADDR_EXPR : ADDR_EXPR,
                                gnu_result_type, gnu_prefix);

            /* For 'Code_Address, find an inner ADDR_EXPR and mark it
               so that we don't try to build a trampoline.  */
            if (attribute == Attr_Code_Address)
              {
                for (gnu_expr = gnu_result;
                     TREE_CODE (gnu_expr) == NOP_EXPR
                     || TREE_CODE (gnu_expr) == CONVERT_EXPR;
                     gnu_expr = TREE_OPERAND (gnu_expr, 0))
                  TREE_CONSTANT (gnu_expr) = 1;
                  ;

                if (TREE_CODE (gnu_expr) == ADDR_EXPR)
                  TREE_STATIC (gnu_expr) = TREE_CONSTANT (gnu_expr) = 1;
              }

            break;

          case Attr_Size:
          case Attr_Object_Size:
          case Attr_Value_Size:
          case Attr_Max_Size_In_Storage_Elements:

            gnu_expr = gnu_prefix;

            /* Remove NOPS from gnu_expr and conversions from gnu_prefix.
               We only use GNU_EXPR to see if a COMPONENT_REF was involved. */
            while (TREE_CODE (gnu_expr) == NOP_EXPR)
              gnu_expr = TREE_OPERAND (gnu_expr, 0);

            gnu_prefix = remove_conversions (gnu_prefix);
            prefix_unused = 1;
            gnu_type = TREE_TYPE (gnu_prefix);

            /* Replace an unconstrained array type with the type of the
               underlying array.  We can't do this with a call to
               maybe_unconstrained_array since we may have a TYPE_DECL.
               For 'Max_Size_In_Storage_Elements, use the record type
               that will be used to allocate the object and its template.  */

            if (TREE_CODE (gnu_type) == UNCONSTRAINED_ARRAY_TYPE)
              {
                gnu_type = TYPE_OBJECT_RECORD_TYPE (gnu_type);
                if (attribute != Attr_Max_Size_In_Storage_Elements)
                  gnu_type = TREE_TYPE (TREE_CHAIN (TYPE_FIELDS (gnu_type)));
              }

            /* If we are looking for the size of a field, return the
               field size.  Otherwise, if the prefix is an object,
               or if 'Object_Size or 'Max_Size_In_Storage_Elements has
               been specified, the result is the GCC size of the type.
               Otherwise, the result is the RM_Size of the type.  */
            if (TREE_CODE (gnu_prefix) == COMPONENT_REF)
              gnu_result = DECL_SIZE (TREE_OPERAND (gnu_prefix, 1));
            else if (TREE_CODE (gnu_prefix) != TYPE_DECL
                     || attribute == Attr_Object_Size
                     || attribute == Attr_Max_Size_In_Storage_Elements)
              {
                /* If this is a padded type, the GCC size isn't relevant
                   to the programmer.  Normally, what we want is the RM_Size,
                   which was set from the specified size, but if it was not
                   set, we want the size of the relevant field.  Using the MAX
                   of those two produces the right result in all case.  Don't
                   use the size of the field if it's a self-referential type,
                   since that's never what's wanted.  */
                if (TREE_CODE (gnu_type) == RECORD_TYPE
                    && TYPE_IS_PADDING_P (gnu_type)
                    && TREE_CODE (gnu_expr) == COMPONENT_REF)
                  {
                    gnu_result = rm_size (gnu_type);
                    if (! (contains_placeholder_p
                           (DECL_SIZE (TREE_OPERAND (gnu_expr, 1)))))
                      gnu_result
                        = size_binop (MAX_EXPR, gnu_result,
                                      DECL_SIZE (TREE_OPERAND (gnu_expr, 1)));
                  }
                else
                  gnu_result = TYPE_SIZE (gnu_type);
              }
            else
              gnu_result = rm_size (gnu_type);

            if (gnu_result == 0)
              gigi_abort (325);

            /* Deal with a self-referential size by returning the maximum
               size for a type and by qualifying the size with
               the object for 'Size of an object.  */

            if (TREE_CODE (gnu_result) != INTEGER_CST
                && contains_placeholder_p (gnu_result))
              {
                if (TREE_CODE (gnu_prefix) != TYPE_DECL)
                  gnu_result = build (WITH_RECORD_EXPR, TREE_TYPE (gnu_result),
                                      gnu_result, gnu_prefix);
                else
                  gnu_result = max_size (gnu_result, 1);
              }

            /* If the type contains a template, subtract the size of the
               template.  */
            if (TREE_CODE (gnu_type) == RECORD_TYPE
                && TYPE_CONTAINS_TEMPLATE_P (gnu_type))
              gnu_result = size_binop (MINUS_EXPR, gnu_result,
                                       DECL_SIZE (TYPE_FIELDS (gnu_type)));

            /* If the type contains a template, subtract the size of the
               template.  */
            if (TREE_CODE (gnu_type) == RECORD_TYPE
                && TYPE_CONTAINS_TEMPLATE_P (gnu_type))
              gnu_result = size_binop (MINUS_EXPR, gnu_result,
                                       DECL_SIZE (TYPE_FIELDS (gnu_type)));

            gnu_result_type = get_unpadded_type (Etype (gnat_node));

            /* Always perform division using unsigned arithmetic as the
               size cannot be negative, but may be an overflowed positive
               value. This provides correct results for sizes up to 512 MB.
               ??? Size should be calculated in storage elements directly.  */

            if (attribute == Attr_Max_Size_In_Storage_Elements)
              gnu_result = convert (sizetype,
                                    fold (build (CEIL_DIV_EXPR, bitsizetype,
                                                 gnu_result,
                                                 bitsize_unit_node)));
            break;

          case Attr_Alignment:
            if (TREE_CODE (gnu_prefix) == COMPONENT_REF
                && (TREE_CODE (TREE_TYPE (TREE_OPERAND (gnu_prefix, 0)))
                    == RECORD_TYPE)
                && (TYPE_IS_PADDING_P
                    (TREE_TYPE (TREE_OPERAND (gnu_prefix, 0)))))
              gnu_prefix = TREE_OPERAND (gnu_prefix, 0);

            gnu_type = TREE_TYPE (gnu_prefix);
            gnu_result_type = get_unpadded_type (Etype (gnat_node));
            prefix_unused = 1;

            if (TREE_CODE (gnu_prefix) == COMPONENT_REF)
              gnu_result
                = size_int (DECL_ALIGN (TREE_OPERAND (gnu_prefix, 1)));
            else
              gnu_result = size_int (TYPE_ALIGN (gnu_type) / BITS_PER_UNIT);
            break;

          case Attr_First:
          case Attr_Last:
          case Attr_Range_Length:
            prefix_unused = 1;

            if (INTEGRAL_TYPE_P (gnu_type)
                || TREE_CODE (gnu_type) == REAL_TYPE)
              {
                gnu_result_type = get_unpadded_type (Etype (gnat_node));

                if (attribute == Attr_First)
                  gnu_result = TYPE_MIN_VALUE (gnu_type);
                else if (attribute == Attr_Last)
                  gnu_result = TYPE_MAX_VALUE (gnu_type);
                else
                  gnu_result
                    = build_binary_op
                      (MAX_EXPR, get_base_type (gnu_result_type),
                       build_binary_op
                       (PLUS_EXPR, get_base_type (gnu_result_type),
                        build_binary_op (MINUS_EXPR,
                                         get_base_type (gnu_result_type),
                                         convert (gnu_result_type,
                                                  TYPE_MAX_VALUE (gnu_type)),
                                         convert (gnu_result_type,
                                                  TYPE_MIN_VALUE (gnu_type))),
                        convert (gnu_result_type, integer_one_node)),
                       convert (gnu_result_type, integer_zero_node));

                break;
              }
            /* ... fall through ... */
          case Attr_Length:
            {
              int Dimension
                = (Present (Expressions (gnat_node))
                   ? UI_To_Int (Intval (First (Expressions (gnat_node))))
                   : 1);

              /* Emit access check if necessary */
              if (Do_Access_Check (gnat_node))
                gnu_prefix = emit_access_check (gnu_prefix);

              /* Make sure any implicit dereference gets done.  */
              gnu_prefix = maybe_implicit_deref (gnu_prefix);
              gnu_prefix = maybe_unconstrained_array (gnu_prefix);
              gnu_type = TREE_TYPE (gnu_prefix);
              prefix_unused = 1;
              gnu_result_type = get_unpadded_type (Etype (gnat_node));

              if (TYPE_CONVENTION_FORTRAN_P (gnu_type))
                {
                  int ndim;
                  tree gnu_type_temp;

                  for (ndim = 1, gnu_type_temp = gnu_type;
                       TREE_CODE (TREE_TYPE (gnu_type_temp)) == ARRAY_TYPE
                       && TYPE_MULTI_ARRAY_P (TREE_TYPE (gnu_type_temp));
                       ndim++, gnu_type_temp = TREE_TYPE (gnu_type_temp))
                    ;

                  Dimension = ndim + 1 - Dimension;
                }

              for (; Dimension > 1; Dimension--)
                gnu_type = TREE_TYPE (gnu_type);

              if (TREE_CODE (gnu_type) != ARRAY_TYPE)
                gigi_abort (309);

              if (attribute == Attr_First)
                gnu_result
                  = TYPE_MIN_VALUE (TYPE_INDEX_TYPE (TYPE_DOMAIN (gnu_type)));
              else if (attribute == Attr_Last)
                gnu_result
                  = TYPE_MAX_VALUE (TYPE_INDEX_TYPE (TYPE_DOMAIN (gnu_type)));
              else
                /* 'Length or 'Range_Length.  */
                {
                  tree gnu_compute_type
                    = signed_or_unsigned_type
                      (0, get_base_type (gnu_result_type));

                  gnu_result
                  = build_binary_op
                    (MAX_EXPR, gnu_compute_type,
                     build_binary_op
                     (PLUS_EXPR, gnu_compute_type,
                      build_binary_op 
                      (MINUS_EXPR, gnu_compute_type,
                       convert (gnu_compute_type,
                                TYPE_MAX_VALUE
                                (TYPE_INDEX_TYPE (TYPE_DOMAIN (gnu_type)))),
                       convert (gnu_compute_type,
                                TYPE_MIN_VALUE
                                (TYPE_INDEX_TYPE (TYPE_DOMAIN (gnu_type))))),
                      convert (gnu_compute_type, integer_one_node)),
                     convert (gnu_compute_type, integer_zero_node));
                }

              /* If this has a PLACEHOLDER_EXPR, qualify it by the object
                 we are handling.  Note that these attributes could not
                 have been used on an unconstrained array type.  */
              if (TREE_CODE (gnu_result) != INTEGER_CST
                  && contains_placeholder_p (gnu_result))
                gnu_result = build (WITH_RECORD_EXPR, TREE_TYPE (gnu_result),
                                    gnu_result, gnu_prefix);

              break;
            }

          case Attr_Bit_Position:
          case Attr_Position:
          case Attr_First_Bit:
          case Attr_Last_Bit:
          case Attr_Bit:
            {
              HOST_WIDE_INT bitsize;
              HOST_WIDE_INT bitpos;
              tree gnu_offset;
              tree gnu_field_bitpos;
              tree gnu_field_offset;
              tree gnu_inner;
              enum machine_mode mode;
              int unsignedp, volatilep;
              unsigned int alignment;

              gnu_result_type = get_unpadded_type (Etype (gnat_node));
              gnu_prefix = remove_conversions (gnu_prefix);
              prefix_unused = 1;

              /* We can have 'Bit on any object, but if it isn't a
                 COMPONENT_REF, the result is zero.  Do not allow
                 'Bit on a bare component, though.  */
              if (attribute == Attr_Bit
                  && TREE_CODE (gnu_prefix) != COMPONENT_REF
                  && TREE_CODE (gnu_prefix) != FIELD_DECL)
                {
                  gnu_result = integer_zero_node;
                  break;
                }

              else if (TREE_CODE (gnu_prefix) != COMPONENT_REF
                       && ! (attribute == Attr_Bit_Position
                             && TREE_CODE (gnu_prefix) == FIELD_DECL))
                gigi_abort (310);

              get_inner_reference (gnu_prefix, &bitsize, &bitpos, &gnu_offset,
                                   &mode, &unsignedp, &volatilep, &alignment);


              if (TREE_CODE (gnu_prefix) == COMPONENT_REF)
                {
                  gnu_field_bitpos
                    = bit_position (TREE_OPERAND (gnu_prefix, 1));
                  gnu_field_offset
                    = byte_position (TREE_OPERAND (gnu_prefix, 1));

                  for (gnu_inner = TREE_OPERAND (gnu_prefix, 0);
                       TREE_CODE (gnu_inner) == COMPONENT_REF
                       && DECL_INTERNAL_P (TREE_OPERAND (gnu_inner, 1));
                       gnu_inner = TREE_OPERAND (gnu_inner, 0))
                    {
                      gnu_field_bitpos
                        = size_binop (PLUS_EXPR, gnu_field_bitpos,
                                      bit_position (TREE_OPERAND (gnu_inner,
                                                                  1)));
                      gnu_field_offset
                        = size_binop (PLUS_EXPR, gnu_field_offset,
                                      byte_position (TREE_OPERAND (gnu_inner,
                                                                   1)));
                    }
                }
              else if (TREE_CODE (gnu_prefix) == FIELD_DECL)
                {
                  gnu_field_bitpos = bit_position (gnu_prefix);
                  gnu_field_offset = byte_position (gnu_prefix);
                }
              else
                {
                  gnu_field_bitpos = bitsize_zero_node;
                  gnu_field_offset = size_zero_node;
                }

              switch (attribute)
                {
                case Attr_Position:
                  gnu_result = gnu_field_offset;
                  break;


                case Attr_First_Bit:
                case Attr_Bit:
                  gnu_result = size_int (bitpos % BITS_PER_UNIT);
                  break;


                case Attr_Last_Bit:
                  gnu_result = bitsize_int (bitpos % BITS_PER_UNIT);
                  gnu_result
                    = size_binop (PLUS_EXPR, gnu_result,
                                  TYPE_SIZE (TREE_TYPE (gnu_prefix)));
                  gnu_result = size_binop (MINUS_EXPR, gnu_result,
                                           bitsize_one_node);
                  break;

                case Attr_Bit_Position:
                  gnu_result = gnu_field_bitpos;
                  break;
                }

              /* If this has a PLACEHOLDER_EXPR, qualify it by the object
                 we are handling. */
              if (TREE_CODE (gnu_result) != INTEGER_CST
                  && contains_placeholder_p (gnu_result))
                gnu_result = build (WITH_RECORD_EXPR, TREE_TYPE (gnu_result),
                                    gnu_result, gnu_prefix);

              break;
            }

          case Attr_Min:
          case Attr_Max:
            gnu_lhs = gnat_to_gnu (First (Expressions (gnat_node)));
            gnu_rhs =  gnat_to_gnu (Next (First (Expressions (gnat_node))));

            gnu_result_type = get_unpadded_type (Etype (gnat_node));
            gnu_result = build_binary_op (attribute == Attr_Min
                                          ? MIN_EXPR : MAX_EXPR,
                                          gnu_result_type, gnu_lhs, gnu_rhs);
            break;

          case Attr_Passed_By_Reference:
            gnu_result = size_int (default_pass_by_ref (gnu_type)
                                   || must_pass_by_ref (gnu_type));
            gnu_result_type = get_unpadded_type (Etype (gnat_node));
            break;

          case Attr_Component_Size:
            if (TREE_CODE (gnu_prefix) == COMPONENT_REF
                && (TREE_CODE (TREE_TYPE (TREE_OPERAND (gnu_prefix, 0)))
                    == RECORD_TYPE)
                && (TYPE_IS_PADDING_P
                    (TREE_TYPE (TREE_OPERAND (gnu_prefix, 0)))))
              gnu_prefix = TREE_OPERAND (gnu_prefix, 0);

            gnu_prefix = maybe_implicit_deref (gnu_prefix);
            gnu_type = TREE_TYPE (gnu_prefix);

            if (TREE_CODE (gnu_type) == UNCONSTRAINED_ARRAY_TYPE)
              gnu_type
                = TREE_TYPE (TREE_TYPE (TYPE_FIELDS (TREE_TYPE (gnu_type))));

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

            if (TREE_CODE (gnu_type) != ARRAY_TYPE)
              gigi_abort (330);

            /* Note this size cannot be self-referential.  */
            gnu_result = TYPE_SIZE (TREE_TYPE (gnu_type));
            gnu_result_type = get_unpadded_type (Etype (gnat_node));
            prefix_unused = 1;
            break;

          case Attr_Null_Parameter:
            /* This is just a zero cast to the pointer type for
               our prefix and dereferenced.  */
            gnu_result_type = get_unpadded_type (Etype (gnat_node));
            gnu_result
              = build_unary_op (INDIRECT_REF, NULL_TREE,
                                convert (build_pointer_type (gnu_result_type),
                                         integer_zero_node));
            TREE_PRIVATE (gnu_result) = 1;
            break;

          case Attr_Mechanism_Code:
            {
              int code;
              Entity_Id gnat_obj = Entity (Prefix (gnat_node));

              prefix_unused = 1;
              gnu_result_type = get_unpadded_type (Etype (gnat_node));
              if (Present (Expressions (gnat_node)))
                {
                  int i = UI_To_Int (Intval (First (Expressions (gnat_node))));

                  for (gnat_obj = First_Formal (gnat_obj); i > 1;
                       i--, gnat_obj = Next_Formal (gnat_obj))
                    ;
                }

              code = Mechanism (gnat_obj);
              if (code == Default)
                code = ((present_gnu_tree (gnat_obj)
                         && (DECL_BY_REF_P (get_gnu_tree (gnat_obj))
                             || (DECL_BY_COMPONENT_PTR_P
                                 (get_gnu_tree (gnat_obj)))))
                        ? By_Reference : By_Copy);
              gnu_result = convert (gnu_result_type, size_int (- code));
            }
          break;

          default:
            /* Say we have an unimplemented attribute.  Then set the
               value to be returned to be a zero and hope that's something
               we can convert to the type of this attribute.  */

            post_error ("unimplemented attribute", gnat_node);
            gnu_result_type = get_unpadded_type (Etype (gnat_node));
            gnu_result = integer_zero_node;
            break;
          }

        /* If this is an attribute where the prefix was unused,
           force a use of it if it has a side-effect.  */
        if (prefix_unused && TREE_SIDE_EFFECTS (gnu_prefix))
          gnu_result = fold (build (COMPOUND_EXPR, TREE_TYPE (gnu_result),
                                    gnu_prefix, gnu_result));
      }
      break;

    case N_Reference:
      /* Like 'Access as far as we are concerned.  */
      gnu_result = gnat_to_gnu (Prefix (gnat_node));
      gnu_result = build_unary_op (ADDR_EXPR, NULL_TREE, gnu_result);
      gnu_result_type = get_unpadded_type (Etype (gnat_node));
      break;

    case N_Aggregate:
    case N_Extension_Aggregate:
      {
        tree gnu_aggr_type;

        /* ??? It is wrong to evaluate the type now, but there doesn't
           seem to be any other practical way of doing it.  */

        gnu_aggr_type = gnu_result_type
          = get_unpadded_type (Etype (gnat_node));

        if (TREE_CODE (gnu_result_type) == RECORD_TYPE
            && TYPE_CONTAINS_TEMPLATE_P (gnu_result_type))
          gnu_aggr_type
            = TREE_TYPE (TREE_CHAIN (TYPE_FIELDS (gnu_result_type)));

        if (Null_Record_Present (gnat_node))
          gnu_result = build_constructor (gnu_aggr_type, NULL_TREE);

        else if (TREE_CODE (gnu_aggr_type) == RECORD_TYPE)
          gnu_result
            = assoc_to_constructor (First (Component_Associations (gnat_node)),
                                    gnu_aggr_type);
        else if (TREE_CODE (gnu_aggr_type) == UNION_TYPE)
          {
            /* The first element is the discrimant, which we ignore.  The
               next is the field we're building.  Convert the expression
               to the type of the field and then to the union type.  */
            Node_Id gnat_assoc
              = Next (First (Component_Associations (gnat_node)));
            Entity_Id gnat_field = Entity (First (Choices (gnat_assoc)));
            tree gnu_field_type
              = TREE_TYPE (gnat_to_gnu_entity (gnat_field, NULL_TREE, 0));

            gnu_result = convert (gnu_field_type,
                                  gnat_to_gnu (Expression (gnat_assoc)));
          }
        else if (TREE_CODE (gnu_aggr_type) == ARRAY_TYPE)
          gnu_result = pos_to_constructor (First (Expressions (gnat_node)),
                                           gnu_aggr_type,
                                           Component_Type (Etype (gnat_node)));
        else if (TREE_CODE (gnu_aggr_type) == COMPLEX_TYPE)
          gnu_result
            = build_binary_op
              (COMPLEX_EXPR, gnu_aggr_type,
               gnat_to_gnu (Expression (First
                                        (Component_Associations (gnat_node)))),
               gnat_to_gnu (Expression
                            (Next
                             (First (Component_Associations (gnat_node))))));
        else
          gigi_abort (312);

        gnu_result = convert (gnu_result_type, gnu_result);
      }
      break;

    case N_Null:
      gnu_result = null_pointer_node;
      gnu_result_type = get_unpadded_type (Etype (gnat_node));
      break;

    case N_Type_Conversion:
    case N_Qualified_Expression:
      /* Get the operand expression.  */
      gnu_result = gnat_to_gnu (Expression (gnat_node));
      gnu_result_type = get_unpadded_type (Etype (gnat_node));

      gnu_result
        = convert_with_check (Etype (gnat_node), gnu_result,
                              Do_Overflow_Check (gnat_node),
                              Do_Range_Check (Expression (gnat_node)),
                              Nkind (gnat_node) == N_Type_Conversion
                              && Float_Truncate (gnat_node));
      break;

    case N_Unchecked_Type_Conversion:
      gnu_result = gnat_to_gnu (Expression (gnat_node));
      gnu_result_type = get_unpadded_type (Etype (gnat_node));

      /* If the result is a pointer type, see if we are improperly
         converting to a stricter alignment.  */

      if (STRICT_ALIGNMENT && POINTER_TYPE_P (gnu_result_type)
          && IN (Ekind (Etype (gnat_node)), Access_Kind))
        {
          unsigned int align = known_alignment (gnu_result);
          tree gnu_obj_type = TREE_TYPE (gnu_result_type);
          unsigned int oalign
            = TREE_CODE (gnu_obj_type) == FUNCTION_TYPE
              ? FUNCTION_BOUNDARY : TYPE_ALIGN (gnu_obj_type);

          if (align != 0 && align < oalign && ! TYPE_ALIGN_OK_P (gnu_obj_type))
            post_error_ne_tree_2
              ("?source alignment (^) < alignment of & (^)",
               gnat_node, Designated_Type (Etype (gnat_node)),
               size_int (align / BITS_PER_UNIT), oalign / BITS_PER_UNIT);
        }

      gnu_result = unchecked_convert (gnu_result_type, gnu_result);
      break;

    case N_In:
    case N_Not_In:
      {
        tree gnu_object = gnat_to_gnu (Left_Opnd (gnat_node));
        Node_Id gnat_range = Right_Opnd (gnat_node);
        tree gnu_low;
        tree gnu_high;

        /* GNAT_RANGE is either an N_Range node or an identifier
           denoting a subtype.  */
        if (Nkind (gnat_range) == N_Range)
          {
            gnu_low = gnat_to_gnu (Low_Bound (gnat_range));
            gnu_high = gnat_to_gnu (High_Bound (gnat_range));
          }
        else if (Nkind (gnat_range) == N_Identifier
              || Nkind (gnat_range) == N_Expanded_Name)
          {
            tree gnu_range_type = get_unpadded_type (Entity (gnat_range));

            gnu_low = TYPE_MIN_VALUE (gnu_range_type);
            gnu_high = TYPE_MAX_VALUE (gnu_range_type);
          }
        else
          gigi_abort (313);

        gnu_result_type = get_unpadded_type (Etype (gnat_node));

        /* If LOW and HIGH are identical, perform an equality test.
           Otherwise, ensure that GNU_OBJECT is only evaluated once
           and perform a full range test.  */
        if (operand_equal_p (gnu_low, gnu_high, 0))
          gnu_result = build_binary_op (EQ_EXPR, gnu_result_type,
                                        gnu_object, gnu_low);
        else
          {
            gnu_object = make_save_expr (gnu_object);
            gnu_result
              = build_binary_op (TRUTH_ANDIF_EXPR, gnu_result_type,
                                 build_binary_op (GE_EXPR, gnu_result_type,
                                                  gnu_object, gnu_low),
                                 build_binary_op (LE_EXPR, gnu_result_type,
                                                  gnu_object, gnu_high));
          }

        if (Nkind (gnat_node) == N_Not_In)
          gnu_result = invert_truthvalue (gnu_result);
      }
      break;

    case N_Op_Divide:
      gnu_lhs = gnat_to_gnu (Left_Opnd (gnat_node));
      gnu_rhs = gnat_to_gnu (Right_Opnd (gnat_node));
      gnu_result_type = get_unpadded_type (Etype (gnat_node));
      gnu_result = build_binary_op (FLOAT_TYPE_P (gnu_result_type)
                                    ? RDIV_EXPR
                                    : (Rounded_Result (gnat_node)
                                       ? ROUND_DIV_EXPR : TRUNC_DIV_EXPR),
                                    gnu_result_type, gnu_lhs, gnu_rhs);
      break;

    case N_And_Then: case N_Or_Else:
      {
        enum tree_code code = gnu_codes[Nkind (gnat_node)];
        tree gnu_rhs_side;

        /* The elaboration of the RHS may generate code.  If so,
           we need to make sure it gets executed after the LHS.  */
        gnu_lhs = gnat_to_gnu (Left_Opnd (gnat_node));
        clear_last_expr ();
        gnu_rhs_side = expand_start_stmt_expr ();
        gnu_rhs = gnat_to_gnu (Right_Opnd (gnat_node));
        expand_end_stmt_expr (gnu_rhs_side);
        gnu_result_type = get_unpadded_type (Etype (gnat_node));

        if (RTL_EXPR_SEQUENCE (gnu_rhs_side) != 0)
          gnu_rhs = build (COMPOUND_EXPR, gnu_result_type, gnu_rhs_side,
                           gnu_rhs);

        gnu_result = build_binary_op (code, gnu_result_type, gnu_lhs, gnu_rhs);
      }
      break;

    case N_Op_Or:    case N_Op_And:      case N_Op_Xor:
      /* These can either be operations on booleans or on modular types.
         Fall through for boolean types since that's the way GNU_CODES is
         set up.  */
      if (IN (Ekind (Underlying_Type (Etype (gnat_node))),
              Modular_Integer_Kind))
        {
          enum tree_code code
            = (Nkind (gnat_node) == N_Op_Or ? BIT_IOR_EXPR
               : Nkind (gnat_node) == N_Op_And ? BIT_AND_EXPR
               : BIT_XOR_EXPR);

          gnu_lhs = gnat_to_gnu (Left_Opnd (gnat_node));
          gnu_rhs = gnat_to_gnu (Right_Opnd (gnat_node));
          gnu_result_type = get_unpadded_type (Etype (gnat_node));
          gnu_result = build_binary_op (code, gnu_result_type,
                                        gnu_lhs, gnu_rhs);
          break;
        }

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

    case N_Op_Eq:    case N_Op_Ne:       case N_Op_Lt:
    case N_Op_Le:    case N_Op_Gt:       case N_Op_Ge:
    case N_Op_Add:   case N_Op_Subtract: case N_Op_Multiply:
    case N_Op_Mod:   case N_Op_Rem:
    case N_Op_Rotate_Left:
    case N_Op_Rotate_Right:
    case N_Op_Shift_Left:
    case N_Op_Shift_Right:
    case N_Op_Shift_Right_Arithmetic:
      {
        enum tree_code code = gnu_codes[Nkind (gnat_node)];
        tree gnu_type;

        gnu_lhs = gnat_to_gnu (Left_Opnd (gnat_node));
        gnu_rhs = gnat_to_gnu (Right_Opnd (gnat_node));
        gnu_type = gnu_result_type = get_unpadded_type (Etype (gnat_node));

        /* If this is a comparison operator, convert any references to
           an unconstrained array value into a reference to the
           actual array.  */
        if (TREE_CODE_CLASS (code) == '<')
          {
            gnu_lhs = maybe_unconstrained_array (gnu_lhs);
            gnu_rhs = maybe_unconstrained_array (gnu_rhs);
          }

        /* If this is a shift whose count is not guaranteed to be correct,
           we need to adjust the shift count.  */
        if (IN (Nkind (gnat_node), N_Op_Shift)
            && ! Shift_Count_OK (gnat_node))
          {
            tree gnu_count_type = get_base_type (TREE_TYPE (gnu_rhs));
            tree gnu_max_shift
              = convert (gnu_count_type, TYPE_SIZE (gnu_type));

            if (Nkind (gnat_node) == N_Op_Rotate_Left
                || Nkind (gnat_node) == N_Op_Rotate_Right)
              gnu_rhs = build_binary_op (TRUNC_MOD_EXPR, gnu_count_type,
                                         gnu_rhs, gnu_max_shift);
            else if (Nkind (gnat_node) == N_Op_Shift_Right_Arithmetic)
              gnu_rhs
                = build_binary_op
                  (MIN_EXPR, gnu_count_type,
                   build_binary_op (MINUS_EXPR,
                                    gnu_count_type,
                                    gnu_max_shift,
                                    convert (gnu_count_type,
                                             integer_one_node)),
                   gnu_rhs);
          }

        /* For right shifts, the type says what kind of shift to do,
           so we may need to choose a different type.  */
        if (Nkind (gnat_node) == N_Op_Shift_Right
            && ! TREE_UNSIGNED (gnu_type))
          gnu_type = unsigned_type (gnu_type);
        else if (Nkind (gnat_node) == N_Op_Shift_Right_Arithmetic
                 && TREE_UNSIGNED (gnu_type))
          gnu_type = signed_type (gnu_type);

        if (gnu_type != gnu_result_type)
          {
            gnu_lhs = convert (gnu_type, gnu_lhs);
            gnu_rhs = convert (gnu_type, gnu_rhs);
          }

        gnu_result = build_binary_op (code, gnu_type, gnu_lhs, gnu_rhs);

        /* If this is a logical shift with the shift count not verified,
           we must return zero if it is too large.  We cannot compensate
           above in this case.  */
        if ((Nkind (gnat_node) == N_Op_Shift_Left
             || Nkind (gnat_node) == N_Op_Shift_Right)
            && ! Shift_Count_OK (gnat_node))
          gnu_result
            = build_cond_expr
              (gnu_type, 
               build_binary_op (GE_EXPR, integer_type_node,
                                gnu_rhs,
                                convert (TREE_TYPE (gnu_rhs),
                                         TYPE_SIZE (gnu_type))),
               convert (gnu_type, integer_zero_node),
               gnu_result);
      }
      break;

    case N_Conditional_Expression:
      {
        tree gnu_cond = gnat_to_gnu (First (Expressions (gnat_node)));
        tree gnu_true = gnat_to_gnu (Next (First (Expressions (gnat_node))));
        tree gnu_false
          = gnat_to_gnu (Next (Next (First (Expressions (gnat_node)))));

        gnu_result_type = get_unpadded_type (Etype (gnat_node));
        gnu_result = build_cond_expr (gnu_result_type,
                                      truthvalue_conversion (gnu_cond),
                                      gnu_true, gnu_false);
      }
      break;

    case N_Op_Plus:
      gnu_result = gnat_to_gnu (Right_Opnd (gnat_node));
      gnu_result_type = get_unpadded_type (Etype (gnat_node));
      break;

    case N_Op_Not:
      /* This case can apply to a boolean or a modular type.
         Fall through for a boolean operand since GNU_CODES is set
         up to handle this.  */
      if (IN (Ekind (Etype (gnat_node)), Modular_Integer_Kind))
        {
          gnu_expr = gnat_to_gnu (Right_Opnd (gnat_node));
          gnu_result_type = get_unpadded_type (Etype (gnat_node));
          gnu_result = build_unary_op (BIT_NOT_EXPR, gnu_result_type,
                                       gnu_expr);
          break;
        }

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

    case N_Op_Minus:  case N_Op_Abs:
      gnu_expr = gnat_to_gnu (Right_Opnd (gnat_node));

      if (Ekind (Etype (gnat_node)) != E_Private_Type) 
         gnu_result_type = get_unpadded_type (Etype (gnat_node));
      else
         gnu_result_type = get_unpadded_type (Base_Type
                                              (Full_View (Etype (gnat_node))));

      gnu_result = build_unary_op (gnu_codes[Nkind (gnat_node)],
                                   gnu_result_type, gnu_expr);
      break;

    case N_Allocator:
      {
        tree gnu_init = 0;
        tree gnu_type;

        gnat_temp = Expression (gnat_node);

        /* The Expression operand can either be an N_Identifier or
           Expanded_Name, which must represent a type, or a
           N_Qualified_Expression, which contains both the object type and an
           initial value for the object.  */
        if (Nkind (gnat_temp) == N_Identifier
            || Nkind (gnat_temp) == N_Expanded_Name)
          gnu_type = gnat_to_gnu_type (Entity (gnat_temp));
        else if (Nkind (gnat_temp) == N_Qualified_Expression)
          {
            Entity_Id gnat_desig_type
              = Designated_Type (Underlying_Type (Etype (gnat_node)));

            gnu_init = gnat_to_gnu (Expression (gnat_temp));

            gnu_init = maybe_unconstrained_array (gnu_init);
            if (Do_Range_Check (Expression (gnat_temp)))
              gnu_init = emit_range_check (gnu_init, gnat_desig_type);

            if (Is_Elementary_Type (gnat_desig_type)
                || Is_Constrained (gnat_desig_type))
              {
                gnu_type = gnat_to_gnu_type (gnat_desig_type);
                gnu_init = convert (gnu_type, gnu_init);
              }
            else
              {
                gnu_type = gnat_to_gnu_type (Etype (Expression (gnat_temp)));
                if (TREE_CODE (gnu_type) == UNCONSTRAINED_ARRAY_TYPE)
                  gnu_type = TREE_TYPE (gnu_init);

                gnu_init = convert (gnu_type, gnu_init);
              }
          }
        else
          gigi_abort (315);

        gnu_result_type = get_unpadded_type (Etype (gnat_node));
        return build_allocator (gnu_type, gnu_init, gnu_result_type,
                                Procedure_To_Call (gnat_node),
                                Storage_Pool (gnat_node));
      }
      break;

    /***************************/
    /* Chapter 5: Statements:  */
    /***************************/

    case N_Label:
      if (! type_annotate_only)
        {
          tree gnu_label = gnat_to_gnu (Identifier (gnat_node));
          Node_Id gnat_parent = Parent (gnat_node);

          expand_label (gnu_label);

          /* If this is the first label of an exception handler, we must
             mark that any CALL_INSN can jump to it.  */
          if (Present (gnat_parent)
              && Nkind (gnat_parent) == N_Exception_Handler
              && First (Statements (gnat_parent)) == gnat_node)
            nonlocal_goto_handler_labels
              = gen_rtx_EXPR_LIST (VOIDmode, label_rtx (gnu_label),
                                   nonlocal_goto_handler_labels);
        }
      break;

    case N_Null_Statement:
      break;

    case N_Assignment_Statement:
      if (type_annotate_only)
        break;

      /* Get the LHS and RHS of the statement and convert any reference to an
         unconstrained array into a reference to the underlying array.  */
      gnu_lhs = maybe_unconstrained_array (gnat_to_gnu (Name (gnat_node)));
      gnu_rhs
        = maybe_unconstrained_array (gnat_to_gnu (Expression (gnat_node)));

      /* If range check is needed, emit code to generate it */
      if (Do_Range_Check (Expression (gnat_node)))
        gnu_rhs = emit_range_check (gnu_rhs, Etype (Name (gnat_node)));

      set_lineno (gnat_node, 1);

      /* If either side's type has a size that overflows, convert this
         into raise of Storage_Error: execution shouldn't have gotten
         here anyway.  */
      if ((TREE_CODE (TYPE_SIZE (TREE_TYPE (gnu_lhs))) == INTEGER_CST
           && TREE_OVERFLOW (TYPE_SIZE (TREE_TYPE (gnu_lhs))))
          || (TREE_CODE (TYPE_SIZE (TREE_TYPE (gnu_rhs))) == INTEGER_CST
              && TREE_OVERFLOW (TYPE_SIZE (TREE_TYPE (gnu_rhs)))))
        expand_expr_stmt (build_call_raise (raise_storage_error_decl));
      else
        expand_expr_stmt (build_binary_op (MODIFY_EXPR, NULL_TREE,
                                           gnu_lhs, gnu_rhs));
      break;

    case N_If_Statement:
      /* Start an IF statement giving the condition.  */
      gnu_expr = gnat_to_gnu (Condition (gnat_node));
      set_lineno (gnat_node, 1);
      expand_start_cond (gnu_expr, 0);

      /* Generate code for the statements to be executed if the condition
         is true.  */

      for (gnat_temp = First (Then_Statements (gnat_node));
           Present (gnat_temp);
           gnat_temp = Next (gnat_temp))
        gnat_to_code (gnat_temp);

      /* Generate each of the "else if" parts.  */
      if (Present (Elsif_Parts (gnat_node)))
        {
          for (gnat_temp = First (Elsif_Parts (gnat_node));
               Present (gnat_temp);
               gnat_temp = Next (gnat_temp))
            {
              Node_Id gnat_statement;

              expand_start_else ();

              /* Set up the line numbers for each condition we test.  */
              set_lineno (Condition (gnat_temp), 1);
              expand_elseif (gnat_to_gnu (Condition (gnat_temp)));

              for (gnat_statement = First (Then_Statements (gnat_temp));
                   Present (gnat_statement);
                   gnat_statement = Next (gnat_statement))
                gnat_to_code (gnat_statement);
            }
        }

      /* Finally, handle any statements in the "else" part.  */
      if (Present (Else_Statements (gnat_node)))
        {
          expand_start_else ();

          for (gnat_temp = First (Else_Statements (gnat_node));
               Present (gnat_temp);
               gnat_temp = Next (gnat_temp))
            gnat_to_code (gnat_temp);
        }

      expand_end_cond ();
      break;

    case N_Case_Statement:
      {
        Node_Id gnat_when;
        Node_Id gnat_choice;
        tree gnu_label;
        Node_Id gnat_statement;

        gnu_expr = gnat_to_gnu (Expression (gnat_node));
        gnu_expr = convert (get_base_type (TREE_TYPE (gnu_expr)), gnu_expr);

        set_lineno (gnat_node, 1);
        expand_start_case (1, gnu_expr, TREE_TYPE (gnu_expr), "case");

        for (gnat_when = First_Non_Pragma (Alternatives (gnat_node));
             Present (gnat_when);
             gnat_when = Next_Non_Pragma (gnat_when))
          {
            /* First compile all the different case choices for the  current
               WHEN alternative.  */

            for (gnat_choice = First (Discrete_Choices (gnat_when));
                 Present (gnat_choice); gnat_choice = Next (gnat_choice))
              {
                int error_code;

                gnu_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);

                set_lineno (gnat_choice, 1);
                switch (Nkind (gnat_choice))
                  {
                  case N_Range:
                    /* Abort on all errors except range empty, which
                       means we ignore this alternative.  */
                    error_code
                      = pushcase_range (gnat_to_gnu (Low_Bound (gnat_choice)),
                                        gnat_to_gnu (High_Bound (gnat_choice)),
                                        convert, gnu_label, 0);

                    if (error_code != 0 && error_code != 4)
                      gigi_abort (332);
                    break;

                  case N_Subtype_Indication:
                    error_code
                      = pushcase_range
                        (gnat_to_gnu (Low_Bound (Range_Expression
                                                 (Constraint (gnat_choice)))),
                         gnat_to_gnu (High_Bound (Range_Expression
                                                  (Constraint (gnat_choice)))),
                         convert, gnu_label, 0);

                    if (error_code != 0 && error_code != 4)
                      gigi_abort (332);
                    break;

                  case N_Identifier:
                  case N_Expanded_Name:
                    /* This represents either a subtype range or a static value
                       of some kind; Ekind says which.  If a static value,
                       fall through to the next case.  */
                    if (IN (Ekind (Entity (gnat_choice)), Type_Kind))
                      {
                        tree type = get_unpadded_type (Entity (gnat_choice));

                        error_code
                          = pushcase_range (fold (TYPE_MIN_VALUE (type)),
                                            fold (TYPE_MAX_VALUE (type)),
                                            convert, gnu_label, 0);

                        if (error_code != 0 && error_code != 4)
                          gigi_abort (332);
                        break;
                      }
                    /* ... fall through ... */
                  case N_Character_Literal:
                  case N_Integer_Literal:
                    if (pushcase (gnat_to_gnu (gnat_choice), convert,
                                  gnu_label, 0))
                      gigi_abort (332);
                    break;

                  case N_Others_Choice:
                    if (pushcase (NULL_TREE, convert, gnu_label, 0))
                      gigi_abort (332);
                    break;

                  default:
                    gigi_abort (316);
                  }
              }

            /* After compiling the choices attached to the WHEN compile the
               body of statements that have to be executed, should the
               "WHEN ... =>" be taken.  */
            for (gnat_statement = First (Statements (gnat_when));
                 Present (gnat_statement);
                 gnat_statement = Next (gnat_statement))
              gnat_to_code (gnat_statement);

            /* Communicate to GCC that we are done with the current WHEN,
               i.e. insert a "break" statement.  */
            expand_exit_something ();
          }

        expand_end_case (gnu_expr);
      }
      break;

    case N_Loop_Statement:
      {
        /* The loop variable in GCC form, if any. */
        tree gnu_loop_var = NULL_TREE;
        /* PREINCREMENT_EXPR or PREDECREMENT_EXPR.  */
        enum tree_code gnu_update = ERROR_MARK;
        /* Used if this is a named loop for so EXIT can work.  */
        struct nesting *loop_id;
        /* Condition to continue loop tested at top of loop.  */
        tree gnu_top_condition = integer_one_node;
        /* Similar, but tested at bottom of loop.  */
        tree gnu_bottom_condition = integer_one_node;
        Node_Id gnat_statement;
        Node_Id gnat_iter_scheme = Iteration_Scheme (gnat_node);
        Node_Id gnat_top_condition = Empty;
        int enclosing_if_p = 0;

        /* Set the condition that under which the loop should continue.
           For "LOOP .... END LOOP;" the condition is always true.  */
        if (No (gnat_iter_scheme))
          ;
        /* The case "WHILE condition LOOP ..... END LOOP;" */
        else if (Present (Condition (gnat_iter_scheme)))
          gnat_top_condition = Condition (gnat_iter_scheme);
        else
          {
            /* We have an iteration scheme.  */
            Node_Id gnat_loop_spec
              = Loop_Parameter_Specification (gnat_iter_scheme);
            Entity_Id gnat_loop_var = Defining_Entity (gnat_loop_spec);
            Entity_Id gnat_type = Etype (gnat_loop_var);
            tree gnu_type = get_unpadded_type (gnat_type);
            tree gnu_low = TYPE_MIN_VALUE (gnu_type);
            tree gnu_high = TYPE_MAX_VALUE (gnu_type);
            int reversep = Reverse_Present (gnat_loop_spec);
            tree gnu_first = reversep ? gnu_high : gnu_low;
            tree gnu_last = reversep ? gnu_low : gnu_high;
            enum tree_code end_code = reversep ? GE_EXPR : LE_EXPR;
            tree gnu_base_type = get_base_type (gnu_type);
            tree gnu_limit
              = (reversep ? TYPE_MIN_VALUE (gnu_base_type)
                 : TYPE_MAX_VALUE (gnu_base_type));

            /* We know the loop variable will not overflow if GNU_LAST is
               a constant and is not equal to GNU_LIMIT.  If it might
               overflow, we have to move the limit test to the end of
               the loop.  In that case, we have to test for an
               empty loop outside the loop.  */
            if (TREE_CODE (gnu_last) != INTEGER_CST
                || TREE_CODE (gnu_limit) != INTEGER_CST
                || tree_int_cst_equal (gnu_last, gnu_limit))
              {
                gnu_expr = build_binary_op (LE_EXPR, integer_type_node,
                                            gnu_low, gnu_high);
                set_lineno (gnat_loop_spec, 1);
                expand_start_cond (gnu_expr, 0);
                enclosing_if_p = 1;
              }

            /* Open a new nesting level that will surround the loop to declare
               the loop index variable.  */
            pushlevel (0);
            expand_start_bindings (0);

            /* Declare the loop index and set it to its initial value.  */
            gnu_loop_var = gnat_to_gnu_entity (gnat_loop_var, gnu_first, 1);
            if (DECL_BY_REF_P (gnu_loop_var))
              gnu_loop_var = build_unary_op (INDIRECT_REF, NULL_TREE,
                                             gnu_loop_var);

            /* The loop variable might be a padded type, so use `convert' to
               get a reference to the inner variable if so.  */
            gnu_loop_var = convert (get_base_type (gnu_type), gnu_loop_var);

            /* Set either the top or bottom exit condition as
               appropriate depending on whether we know an overflow
               cannot occur or not. */
            if (enclosing_if_p)
              gnu_bottom_condition
                = build_binary_op (NE_EXPR, integer_type_node,
                                   gnu_loop_var, gnu_last);
            else
              gnu_top_condition
                = build_binary_op (end_code, integer_type_node,
                                   gnu_loop_var, gnu_last);

            gnu_update = reversep ? PREDECREMENT_EXPR : PREINCREMENT_EXPR;
          }

        set_lineno (gnat_node, 1);
        if (gnu_loop_var)
          loop_id = expand_start_loop_continue_elsewhere (1);
        else
          loop_id = expand_start_loop (1);

        /* If the loop was named, have the name point to this loop.  In this
           case, the association is not a ..._DECL node; in fact, it isn't
           a GCC tree node at all.  Since this name is referenced inside
           the loop, do it before we process the statements of the loop.  */
        if (Present (Identifier (gnat_node)))
          {
            tree gnu_loop_id = make_node (GNAT_LOOP_ID);

            TREE_LOOP_ID (gnu_loop_id) = (rtx) loop_id;
            save_gnu_tree (Entity (Identifier (gnat_node)), gnu_loop_id, 1);
          }

        set_lineno (gnat_node, 1);

        /* We must evaluate the condition after we've entered the
           loop so that any expression actions get done in the right
           place.  */
        if (Present (gnat_top_condition))
          gnu_top_condition = gnat_to_gnu (gnat_top_condition);

        expand_exit_loop_if_false (0, gnu_top_condition);

        /* Make the loop body into its own block, so any allocated
           storage will be released every iteration.  This is needed
           for stack allocation.  */

        pushlevel (0);
        gnu_block_stack
          = tree_cons (gnu_bottom_condition, NULL_TREE, gnu_block_stack);
        expand_start_bindings (0);

        for (gnat_statement = First (Statements (gnat_node));
             Present (gnat_statement);
             gnat_statement = Next (gnat_statement))
          gnat_to_code (gnat_statement);

        expand_end_bindings (getdecls (), kept_level_p (), 0);
        poplevel (kept_level_p (), 1, 0);
        gnu_block_stack = TREE_CHAIN (gnu_block_stack);

        set_lineno (gnat_node, 1);
        expand_exit_loop_if_false (0, gnu_bottom_condition);

        if (gnu_loop_var)
          {
            expand_loop_continue_here ();
            gnu_expr = build_binary_op (gnu_update, TREE_TYPE (gnu_loop_var),
                                        gnu_loop_var,
                                        convert (TREE_TYPE (gnu_loop_var),
                                                 integer_one_node));
            set_lineno (gnat_iter_scheme, 1);
            expand_expr_stmt (gnu_expr);
          }

        set_lineno (gnat_node, 1);
        expand_end_loop ();

        if (gnu_loop_var)
          {
            /* Close the nesting level that sourround the loop that was used to
               declare the loop index variable.   */
            set_lineno (gnat_node, 1);
            expand_end_bindings (getdecls (), 1, 0);
            poplevel (1, 1, 0);
          }

        if (enclosing_if_p)
          {
            set_lineno (gnat_node, 1);
            expand_end_cond ();
          }
      }
      break;

    case N_Block_Statement:
      pushlevel (0);
      gnu_block_stack = tree_cons (NULL_TREE, NULL_TREE, gnu_block_stack);
      expand_start_bindings (0);
      process_decls (Declarations (gnat_node), Empty, Empty, 1, 1);
      gnat_to_code (Handled_Statement_Sequence (gnat_node));
      expand_end_bindings (getdecls (), kept_level_p (), 0);
      poplevel (kept_level_p (), 1, 0);
      gnu_block_stack = TREE_CHAIN (gnu_block_stack);
      if (Present (Identifier (gnat_node)))
        mark_out_of_scope (Entity (Identifier (gnat_node)));
      break;

    case N_Exit_Statement:
      {
        /* Which loop to exit, NULL if the current loop.   */
        struct nesting *loop_id = 0;
        /* The GCC version of the optional GNAT condition node attached to the
           exit statement. Exit the loop if this is false.  */
        tree gnu_cond = integer_zero_node;

        if (Present (Name (gnat_node)))
          loop_id
            = (struct nesting *)
              TREE_LOOP_ID (get_gnu_tree (Entity (Name (gnat_node))));

        if (Present (Condition (gnat_node)))
          gnu_cond
            = invert_truthvalue
              (truthvalue_conversion (gnat_to_gnu (Condition (gnat_node))));

        set_lineno (gnat_node, 1);
        expand_exit_loop_if_false (loop_id, gnu_cond);
      }
      break;

    case N_Return_Statement:
      if (type_annotate_only)
        break;

      {
        /* The gnu function type of the subprogram currently processed.  */
        tree gnu_subprog_type = TREE_TYPE (current_function_decl);
        /* The return value from the subprogram.  */
        tree gnu_ret_val = 0;

        /* If we are dealing with a "return;" from an Ada procedure with
           parameters passed by copy in copy out, we need to return a record
           containing the final values of these parameters.  If the list
           contains only one entry, return just that entry.

           For a full description of the copy in copy out parameter mechanism,
           see the part of the gnat_to_gnu_entity routine dealing with the
           translation of subprograms.

           But if we have a return label defined, convert this into
           a branch to that label.  */

        if (TREE_VALUE (gnu_return_label_stack) != 0)
          expand_goto (TREE_VALUE (gnu_return_label_stack));

        else if (TYPE_CI_CO_LIST (gnu_subprog_type) != NULL_TREE)
          {
            if (list_length (TYPE_CI_CO_LIST (gnu_subprog_type)) == 1)
              gnu_ret_val = TREE_VALUE (TYPE_CI_CO_LIST (gnu_subprog_type));
            else
              gnu_ret_val
                = build_constructor (TREE_TYPE (gnu_subprog_type),
                                     TYPE_CI_CO_LIST (gnu_subprog_type));
          }

        /* If the Ada subprogram is a function, we just need to return the
           expression.   If the subprogram returns an unconstrained
           array, we have to allocate a new version of the result and
           return it.  If we return by reference, return a pointer.  */

        else if (Present (Expression (gnat_node)))
          {
            gnu_ret_val = gnat_to_gnu (Expression (gnat_node));

            /* Do not remove the padding from GNU_RET_VAL if the inner
               type is self-referential since we want to allocate the fixed
               size in that case.  */
            if (TREE_CODE (gnu_ret_val) == COMPONENT_REF
                && (TYPE_IS_PADDING_P
                    (TREE_TYPE (TREE_OPERAND (gnu_ret_val, 0))))
                && contains_placeholder_p
                (TYPE_SIZE (TREE_TYPE (gnu_ret_val))))
              gnu_ret_val = TREE_OPERAND (gnu_ret_val, 0);

            if (TYPE_RETURNS_BY_REF_P (gnu_subprog_type) 
                || By_Ref (gnat_node))
              gnu_ret_val = build_unary_op (ADDR_EXPR, NULL_TREE, gnu_ret_val);

            else if (TYPE_RETURNS_UNCONSTRAINED_P (gnu_subprog_type))
              {
                gnu_ret_val = maybe_unconstrained_array (gnu_ret_val);

                /* We have two cases: either the function returns with
                   depressed stack or not.  If not, we allocate on the
                   secondary stack.  If so, we allocate in the stack frame. 
                   if no copy is needed, the front end will set By_Ref,
                   which we handle in the case above.  */
                if (TYPE_RETURNS_STACK_DEPRESSED (gnu_subprog_type))
                  gnu_ret_val
                    = build_allocator (TREE_TYPE (gnu_ret_val), gnu_ret_val,
                                       TREE_TYPE (gnu_subprog_type), 0, -1);
                else
                  gnu_ret_val
                    = build_allocator (TREE_TYPE (gnu_ret_val), gnu_ret_val,
                                       TREE_TYPE (gnu_subprog_type),
                                       Procedure_To_Call (gnat_node),
                                       Storage_Pool (gnat_node));
              }
          }

        set_lineno (gnat_node, 1);
        if (gnu_ret_val)
          expand_return (build_binary_op (MODIFY_EXPR, NULL_TREE,
                                          DECL_RESULT (current_function_decl),
                                          gnu_ret_val));
        else
          expand_null_return ();

      }
      break;

    case N_Goto_Statement:
      if (type_annotate_only)
        break;

      gnu_expr = gnat_to_gnu (Name (gnat_node));
      TREE_USED (gnu_expr) = 1;
      set_lineno (gnat_node, 1);
      expand_goto (gnu_expr);
      break;

    /****************************/
    /* Chapter 6: Subprograms:  */
    /****************************/

    case N_Subprogram_Declaration:
      /* Unless there is a freeze node, declare the subprogram.  We consider
         this a "definition" even though we're not generating code for
         the subprogram because we will be making the corresponding GCC
         node here.  */

      if (No (Freeze_Node (Defining_Entity (Specification (gnat_node)))))
        gnat_to_gnu_entity (Defining_Entity (Specification (gnat_node)),
                            NULL_TREE, 1);

      break;

    case N_Abstract_Subprogram_Declaration:
      /* This subprogram doesn't exist for code generation purposes, but we
         have to elaborate the types of any parameters, unless they are
         imported types (nothing to generate in this case).  */
      for (gnat_temp
           = First_Formal (Defining_Entity (Specification (gnat_node)));
           Present (gnat_temp);
           gnat_temp = Next_Formal_With_Extras (gnat_temp))
        if (Is_Itype (Etype (gnat_temp))
            && !From_With_Type (Etype (gnat_temp)))
          gnat_to_gnu_entity (Etype (gnat_temp), NULL_TREE, 0);

      break;

    case N_Defining_Program_Unit_Name:
      /* For a child unit identifier go up a level to get the
         specificaton.  We get this when we try to find the spec of
         a child unit package that is the compilation unit being compiled. */
      gnat_to_code (Parent (gnat_node));
      break;

    case N_Subprogram_Body:
      {
        /* Save debug output mode in case it is reset.  */
        enum debug_info_type save_write_symbols = write_symbols;
        struct gcc_debug_hooks *save_debug_hooks = debug_hooks;
        /* Definining identifier of a parameter to the subprogram.  */
        Entity_Id gnat_param;
        /* The defining identifier for the subprogram body. Note that if a
           specification has appeared before for this body, then the identifier
           occurring in that specification will also be a defining identifier
           and all the calls to this subprogram will point to that
           specification.  */
        Entity_Id gnat_subprog_id
          = (Present (Corresponding_Spec (gnat_node))
             ? Corresponding_Spec (gnat_node) : Defining_Entity (gnat_node));

        /* The FUNCTION_DECL node corresponding to the subprogram spec.   */
        tree gnu_subprog_decl;
        /* The FUNCTION_TYPE node corresponding to the subprogram spec.  */
        tree gnu_subprog_type;
        tree gnu_cico_list;

        /* If this is a generic object or if it has been eliminated, 
           ignore it.  */

        if (Ekind (gnat_subprog_id) == E_Generic_Procedure
            || Ekind (gnat_subprog_id) == E_Generic_Function
            || Is_Eliminated (gnat_subprog_id))
          break;

        /* If debug information is suppressed for the subprogram,
           turn debug mode off for the duration of processing.  */
        if (Debug_Info_Off (gnat_subprog_id))
          {
            write_symbols = NO_DEBUG;  
            debug_hooks = &do_nothing_debug_hooks;
          }

        /* If this subprogram acts as its own spec, define it.  Otherwise,
           just get the already-elaborated tree node.  However, if this
           subprogram had its elaboration deferred, we will already have
           made a tree node for it.  So treat it as not being defined in
           that case.  Such a subprogram cannot have an address clause or
           a freeze node, so this test is safe, though it does disable
           some otherwise-useful error checking.  */
        gnu_subprog_decl
          = gnat_to_gnu_entity (gnat_subprog_id, NULL_TREE, 
                                Acts_As_Spec (gnat_node)
                                && ! present_gnu_tree (gnat_subprog_id));

        gnu_subprog_type = TREE_TYPE (gnu_subprog_decl);

        /* Set the line number in the decl to correspond to that of
           the body so that the line number notes are written 
           correctly.  */
        set_lineno (gnat_node, 0);
        DECL_SOURCE_FILE (gnu_subprog_decl) = input_filename;
        DECL_SOURCE_LINE (gnu_subprog_decl) = lineno;

        begin_subprog_body (gnu_subprog_decl);
        set_lineno (gnat_node, 1);

        pushlevel (0);
        gnu_block_stack = tree_cons (NULL_TREE, NULL_TREE, gnu_block_stack);
        expand_start_bindings (0);

        gnu_cico_list = TYPE_CI_CO_LIST (gnu_subprog_type);

        /* If there are OUT parameters, we need to ensure that the
           return statement properly copies them out.  We do this by
           making a new block and converting any inner return into a goto
           to a label at the end of the block.  */

        if (gnu_cico_list != 0)
          {
            gnu_return_label_stack
              = tree_cons (NULL_TREE, 
                           build_decl (LABEL_DECL, NULL_TREE, NULL_TREE),
                           gnu_return_label_stack);
            pushlevel (0);
            expand_start_bindings (0);
          }
        else
          gnu_return_label_stack
            = tree_cons (NULL_TREE, NULL_TREE, gnu_return_label_stack);

        /* See if there are any parameters for which we don't yet have
           GCC entities.  These must be for OUT parameters for which we
           will be making VAR_DECL nodes here.  Fill them in to
           TYPE_CI_CO_LIST, which must contain the empty entry as well.
           We can match up the entries because TYPE_CI_CO_LIST is in the
           order of the parameters.  */

        for (gnat_param = First_Formal (gnat_subprog_id);
             Present (gnat_param);
             gnat_param = Next_Formal_With_Extras (gnat_param))
          if (present_gnu_tree (gnat_param))
            adjust_decl_rtl (get_gnu_tree (gnat_param));
          else
            {
              /* Skip any entries that have been already filled in; they
                 must correspond to IN OUT parameters.  */
            for (; gnu_cico_list != 0 && TREE_VALUE (gnu_cico_list) != 0;
                 gnu_cico_list = TREE_CHAIN (gnu_cico_list))
              ;

            /* Do any needed references for padded types.  */
            TREE_VALUE (gnu_cico_list)
              = convert (TREE_TYPE (TREE_PURPOSE (gnu_cico_list)),
                         gnat_to_gnu_entity (gnat_param, NULL_TREE, 1));
          }

        process_decls (Declarations (gnat_node), Empty, Empty, 1, 1);

        /* Generate the code of the subprogram itself.  A return statement
           will be present and any OUT parameters will be handled there.  */
        gnat_to_code (Handled_Statement_Sequence (gnat_node));

        expand_end_bindings (getdecls (), kept_level_p (), 0);
        poplevel (kept_level_p (), 1, 0);
        gnu_block_stack = TREE_CHAIN (gnu_block_stack);

        if (TREE_VALUE (gnu_return_label_stack) != 0)
          {
            tree gnu_retval;

            expand_end_bindings (NULL_TREE, kept_level_p (), 0);
            poplevel (kept_level_p (), 1, 0);
            expand_label (TREE_VALUE (gnu_return_label_stack));

            gnu_cico_list = TYPE_CI_CO_LIST (gnu_subprog_type);
            set_lineno (gnat_node, 1);
            if (list_length (gnu_cico_list) == 1)
              gnu_retval = TREE_VALUE (gnu_cico_list);
            else
               gnu_retval = build_constructor (TREE_TYPE (gnu_subprog_type),
                                               gnu_cico_list);

            if (DECL_P (gnu_retval) && DECL_BY_REF_P (gnu_retval))
              gnu_retval
                = build_unary_op (INDIRECT_REF, NULL_TREE, gnu_retval);

            expand_return
              (build_binary_op (MODIFY_EXPR, NULL_TREE,
                                DECL_RESULT (current_function_decl),
                                gnu_retval));

          }

        gnu_return_label_stack = TREE_CHAIN (gnu_return_label_stack);

        /* Disconnect the trees for parameters that we made variables for
           from the GNAT entities since these will become unusable after
           we end the function.  */
        for (gnat_param = First_Formal (gnat_subprog_id);
             Present (gnat_param);
             gnat_param = Next_Formal_With_Extras (gnat_param))
          if (TREE_CODE (get_gnu_tree (gnat_param)) == VAR_DECL)
            save_gnu_tree (gnat_param, NULL_TREE, 0);

        end_subprog_body ();
        mark_out_of_scope (Defining_Unit_Name (Specification (gnat_node)));
        write_symbols = save_write_symbols;
        debug_hooks = save_debug_hooks;
      }
      break;

    case N_Function_Call:
    case N_Procedure_Call_Statement:

      if (type_annotate_only)
        break;

      {
        /* The GCC node corresponding to the GNAT subprogram name.  This can
           either be a FUNCTION_DECL node if we are dealing with a standard
           subprogram call, or an indirect reference expression (an
           INDIRECT_REF node) pointing to a subprogram.  */
        tree gnu_subprog_node = gnat_to_gnu (Name (gnat_node));
        /* The FUNCTION_TYPE node giving the GCC type of the subprogram.  */
        tree gnu_subprog_type = TREE_TYPE (gnu_subprog_node);
        tree gnu_subprog_addr
          = build_unary_op (ADDR_EXPR, NULL_TREE, gnu_subprog_node);
        Entity_Id gnat_formal;
        Node_Id gnat_actual;
        tree gnu_actual_list = NULL_TREE;
        tree gnu_name_list = NULL_TREE;
        tree gnu_after_list = NULL_TREE;
        tree gnu_subprog_call;

        switch (Nkind (Name (gnat_node))) 
          {
          case N_Identifier:
          case N_Operator_Symbol:
          case N_Expanded_Name:
          case N_Attribute_Reference:
            if (Is_Eliminated (Entity (Name (gnat_node))))
              post_error_ne ("cannot call eliminated subprogram &!", 
                             gnat_node, Entity (Name (gnat_node)));
          }

        if (TREE_CODE (gnu_subprog_type) != FUNCTION_TYPE)
          gigi_abort (317);

        /* If we are calling a stubbed function, make this into a 
           raise of Program_Error.  Elaborate all our args first.  */

        if (TREE_CODE (gnu_subprog_node) == FUNCTION_DECL
            && DECL_STUBBED_P (gnu_subprog_node))
          {
            for (gnat_actual = First_Actual (gnat_node);
                 Present (gnat_actual);
                 gnat_actual = Next_Actual (gnat_actual))
              expand_expr_stmt (gnat_to_gnu (gnat_actual));

            if (Nkind (gnat_node) == N_Function_Call)
              {
                gnu_result_type = TREE_TYPE (gnu_subprog_type);
                gnu_result
                  = build1 (NULL_EXPR, gnu_result_type,
                            build_call_raise (raise_program_error_decl));
              }
            else
              expand_expr_stmt (build_call_raise (raise_program_error_decl));
            break;
          }

        /* The only way we can be making a call via an access type is
           if Name is an explicit dereference.  In that case, get the
           list of formal args from the type the access type is pointing
           to.  Otherwise, get the formals from entity being called.  */
        if (Nkind (Name (gnat_node)) == N_Explicit_Dereference)
          gnat_formal = First_Formal (Etype (Name (gnat_node)));
        else if (Nkind (Name (gnat_node)) == N_Attribute_Reference)
          /* Assume here that this must be 'Elab_Body or 'Elab_Spec.  */
          gnat_formal = 0;
        else
          gnat_formal = First_Formal (Entity (Name (gnat_node)));

        /* Create the list of the actual parameters as GCC expects it, namely
           a chain of TREE_LIST nodes in which the TREE_VALUE field of each
           node is a parameter-expression and the TREE_PURPOSE field is
           null.  Skip OUT parameters that are not passed by reference.  */

        for (gnat_actual = First_Actual (gnat_node);
             Present (gnat_actual);
             gnat_formal = Next_Formal_With_Extras (gnat_formal),
             gnat_actual = Next_Actual (gnat_actual))
          {
            tree gnu_formal_type = gnat_to_gnu_type (Etype (gnat_formal));
            Node_Id gnat_name
              = ((Nkind (gnat_actual) == N_Unchecked_Type_Conversion)
                ? Expression (gnat_actual) : gnat_actual);
            tree gnu_name = gnat_to_gnu (gnat_name);
            tree gnu_name_type = gnat_to_gnu_type (Etype (gnat_name));
            tree gnu_actual;

            /* If it's possible we may need to use this expression twice,
               make sure than any side-effects are handled via SAVE_EXPRs. 
               Likewise if we need to force side-effects before the call. 
               ??? This is more conservative than we need since we don't
               need to do this for pass-by-ref with no conversion. 
               If we are passing a non-addressable Out or In Out parameter by
               reference, pass the address of a copy and set up to copy back
               out after the call.  */

            if (Ekind (gnat_formal) != E_In_Parameter)
              {
                gnu_name = gnat_stabilize_reference (gnu_name, 1);
                if (! addressable_p (gnu_name)
                    && present_gnu_tree (gnat_formal)
                    && (DECL_BY_REF_P (get_gnu_tree (gnat_formal))
                        || DECL_BY_COMPONENT_PTR_P (get_gnu_tree (gnat_formal))
                        || DECL_BY_DESCRIPTOR_P (get_gnu_tree (gnat_formal))))
                  {
                    tree gnu_copy = gnu_name;

                    /* Remove any unpadding on the actual and make a copy.  
                       But if the actual is a left-justified modular type,
                       first convert to it.  */
                    if (TREE_CODE (gnu_name) == COMPONENT_REF
                        && (TYPE_IS_PADDING_P
                            (TREE_TYPE (TREE_OPERAND (gnu_name, 0)))))
                      gnu_name = gnu_copy = TREE_OPERAND (gnu_name, 0);
                    else if (TREE_CODE (gnu_name_type) == RECORD_TYPE
                             && (TYPE_LEFT_JUSTIFIED_MODULAR_P
                                 (gnu_name_type)))
                      gnu_name = convert (gnu_name_type, gnu_name);

                    gnu_actual = save_expr (gnu_name);

                    /* Set up to move the copy back to the original.  */
                    gnu_after_list = tree_cons (gnu_copy, gnu_actual,
                                                gnu_after_list);

                    gnu_name = gnu_actual;
                  }
              }

            /* If this was a procedure call, we may not have removed any
               padding.  So do it here for the part we will use as an
               input, if any.  */
            gnu_actual = gnu_name;
            if (Ekind (gnat_formal) != E_Out_Parameter
                && TREE_CODE (TREE_TYPE (gnu_actual)) == RECORD_TYPE
                && TYPE_IS_PADDING_P (TREE_TYPE (gnu_actual)))
              gnu_actual = convert (get_unpadded_type (Etype (gnat_actual)),
                                    gnu_actual);

            if (Ekind (gnat_formal) != E_Out_Parameter
                && Nkind (gnat_actual) != N_Unchecked_Type_Conversion
                && Do_Range_Check (gnat_actual))
              gnu_actual = emit_range_check (gnu_actual, Etype (gnat_formal));

            /* Do any needed conversions.  We need only check for
               unchecked conversion since normal conversions will be handled
               by just converting to the formal type.  */
            if (Nkind (gnat_actual) == N_Unchecked_Type_Conversion)
              {
                gnu_actual
                  = unchecked_convert (gnat_to_gnu_type (Etype (gnat_actual)),
                                       gnu_actual);

                /* One we've done the unchecked conversion, we still
                   must ensure that the object is in range of the formal's
                   type.  */
                if (Ekind (gnat_formal) != E_Out_Parameter
                    && Do_Range_Check (gnat_actual))
                  gnu_actual = emit_range_check (gnu_actual,
                                                 Etype (gnat_formal));
              }
            else
              /* We may have suppressed a conversion to the Etype of the
                 actual since the parent is a procedure call.  So add the
                 conversion here.  */
              gnu_actual = convert (gnat_to_gnu_type (Etype (gnat_actual)),
                                    gnu_actual);

            gnu_actual = convert (gnu_formal_type, gnu_actual);

            /* If we have not saved a GCC object for the formal, it means
               it is an OUT parameter not passed by reference.  Otherwise,
               look at the PARM_DECL to see if it is passed by reference. */
            if (present_gnu_tree (gnat_formal)
                && TREE_CODE (get_gnu_tree (gnat_formal)) == PARM_DECL
                && DECL_BY_REF_P (get_gnu_tree (gnat_formal)))
              {
                if (Ekind (gnat_formal) != E_In_Parameter)
                  {
                    gnu_actual = gnu_name;

                    /* If we have a padded type, be sure we've removed the
                       padding.  */
                    if (TREE_CODE (TREE_TYPE (gnu_actual)) == RECORD_TYPE
                        && TYPE_IS_PADDING_P (TREE_TYPE (gnu_actual)))
                      gnu_actual
                        = convert (get_unpadded_type (Etype (gnat_actual)),
                                   gnu_actual);
                  }

                /* The symmetry of the paths to the type of an entity is
                   broken here since arguments don't know that they will
                   be passed by ref. */
                gnu_formal_type = TREE_TYPE (get_gnu_tree (gnat_formal));
                gnu_actual = build_unary_op (ADDR_EXPR, gnu_formal_type,
                                             gnu_actual);
              }
            else if (present_gnu_tree (gnat_formal)
                     && TREE_CODE (get_gnu_tree (gnat_formal)) == PARM_DECL
                     && DECL_BY_COMPONENT_PTR_P (get_gnu_tree (gnat_formal)))
              {
                gnu_formal_type = TREE_TYPE (get_gnu_tree (gnat_formal));
                gnu_actual = maybe_implicit_deref (gnu_actual);
                gnu_actual = maybe_unconstrained_array (gnu_actual);

                if (TREE_CODE (gnu_formal_type) == RECORD_TYPE
                    && TYPE_IS_PADDING_P (gnu_formal_type))
                  {
                    gnu_formal_type
                      = TREE_TYPE (TYPE_FIELDS (gnu_formal_type));
                    gnu_actual = convert (gnu_formal_type, gnu_actual);
                  }

                /* Take the address of the object and convert to the
                   proper pointer type.  We'd like to actually compute
                   the address of the beginning of the array using 
                   an ADDR_EXPR of an ARRAY_REF, but there's a possibility
                   that the ARRAY_REF might return a constant and we'd
                   be getting the wrong address.  Neither approach is
                   exactly correct, but this is the most likely to work
                   in all cases.  */
                gnu_actual = convert (gnu_formal_type,
                                      build_unary_op (ADDR_EXPR, NULL_TREE,
                                                      gnu_actual));
              }
            else if (present_gnu_tree (gnat_formal)
                     && TREE_CODE (get_gnu_tree (gnat_formal)) == PARM_DECL
                     && DECL_BY_DESCRIPTOR_P (get_gnu_tree (gnat_formal)))
              {
                /* If arg is 'Null_Parameter, pass zero descriptor.  */
                if ((TREE_CODE (gnu_actual) == INDIRECT_REF
                     || TREE_CODE (gnu_actual) == UNCONSTRAINED_ARRAY_REF)
                    && TREE_PRIVATE (gnu_actual))
                  gnu_actual
                    = convert (DECL_ARG_TYPE (get_gnu_tree (gnat_formal)),
                               integer_zero_node);
                else
                  gnu_actual
                    = build_unary_op (ADDR_EXPR, NULL_TREE,
                                      fill_vms_descriptor (gnu_actual,
                                                           gnat_formal));
              }
            else
              {
                tree gnu_actual_size = TYPE_SIZE (TREE_TYPE (gnu_actual));

                if (Ekind (gnat_formal) != E_In_Parameter)
                  gnu_name_list
                    = chainon (gnu_name_list,
                               build_tree_list (NULL_TREE, gnu_name));

                if (! present_gnu_tree (gnat_formal)
                    || TREE_CODE (get_gnu_tree (gnat_formal)) != PARM_DECL)
                  continue;

                /* If this is 'Null_Parameter, pass a zero even though we are
                   dereferencing it.  */
                else if (TREE_CODE (gnu_actual) == INDIRECT_REF
                         && TREE_PRIVATE (gnu_actual)
                         && host_integerp (gnu_actual_size, 1)
                         && 0 >= compare_tree_int (gnu_actual_size, 
                                                   BITS_PER_WORD))
                  gnu_actual
                    = unchecked_convert
                      (DECL_ARG_TYPE (get_gnu_tree (gnat_formal)),
                       convert (type_for_size
                                (tree_low_cst (gnu_actual_size, 1), 1),
                                integer_zero_node));
                else
                  gnu_actual
                    = convert (TYPE_MAIN_VARIANT
                               (DECL_ARG_TYPE (get_gnu_tree (gnat_formal))),
                               gnu_actual);
              }

            gnu_actual_list
              = chainon (gnu_actual_list,
                         build_tree_list (NULL_TREE, gnu_actual));
          }

        gnu_subprog_call = build (CALL_EXPR, TREE_TYPE (gnu_subprog_type),
                                  gnu_subprog_addr, gnu_actual_list,
                                  NULL_TREE);
        TREE_SIDE_EFFECTS (gnu_subprog_call) = 1;

        /* If it is a function call, the result is the call expression.  */
        if (Nkind (gnat_node) == N_Function_Call)
          {
            gnu_result = gnu_subprog_call;

            /* If the function returns an unconstrained array or by reference,
               we have to de-dereference the pointer.  */
            if (TYPE_RETURNS_UNCONSTRAINED_P (gnu_subprog_type)
                || TYPE_RETURNS_BY_REF_P (gnu_subprog_type))
              gnu_result = build_unary_op (INDIRECT_REF, NULL_TREE,
                                           gnu_result);

            gnu_result_type = get_unpadded_type (Etype (gnat_node));
          }

        /* If this is the case where the GNAT tree contains a procedure call
           but the Ada procedure has copy in copy out parameters, the special
           parameter passing mechanism must be used.  */
        else if (TYPE_CI_CO_LIST (gnu_subprog_type) != NULL_TREE)
          {
            /* List of FIELD_DECLs associated with the PARM_DECLs of the copy
               in copy out parameters.  */
            tree scalar_return_list = TYPE_CI_CO_LIST (gnu_subprog_type);
            int length = list_length (scalar_return_list);

            if (length > 1)
              {
                tree gnu_name;

                gnu_subprog_call = make_save_expr (gnu_subprog_call);

                /* If any of the names had side-effects, ensure they are
                   all evaluated before the call.  */
                for (gnu_name = gnu_name_list; gnu_name;
                     gnu_name = TREE_CHAIN (gnu_name))
                  if (TREE_SIDE_EFFECTS (TREE_VALUE (gnu_name)))
                    gnu_subprog_call
                      = build (COMPOUND_EXPR, TREE_TYPE (gnu_subprog_call),
                               TREE_VALUE (gnu_name), gnu_subprog_call);
              }

            if (Nkind (Name (gnat_node)) == N_Explicit_Dereference)
              gnat_formal = First_Formal (Etype (Name (gnat_node)));
            else
              gnat_formal = First_Formal (Entity (Name (gnat_node)));

            for (gnat_actual = First_Actual (gnat_node);
                 Present (gnat_actual);
                 gnat_formal = Next_Formal_With_Extras (gnat_formal),
                 gnat_actual = Next_Actual (gnat_actual))
              /* If we are dealing with a copy in copy out parameter, we must
                 retrieve its value from the record returned in the function
                 call.  */
              if (! (present_gnu_tree (gnat_formal)
                     && TREE_CODE (get_gnu_tree (gnat_formal)) == PARM_DECL
                     && (DECL_BY_REF_P (get_gnu_tree (gnat_formal))
                         || (DECL_BY_COMPONENT_PTR_P 
                             (get_gnu_tree (gnat_formal)))
                         || DECL_BY_DESCRIPTOR_P (get_gnu_tree (gnat_formal))))
                  && Ekind (gnat_formal) != E_In_Parameter)
                {
                  /* Get the value to assign to this OUT or IN OUT
                     parameter.  It is either the result of the function if
                     there is only a single such parameter or the appropriate
                     field from the record returned.  */
                  tree gnu_result
                    = length == 1 ? gnu_subprog_call
                      : build_component_ref
                        (gnu_subprog_call, NULL_TREE,
                         TREE_PURPOSE (scalar_return_list));
                  int unchecked_conversion
                    = Nkind (gnat_actual) == N_Unchecked_Type_Conversion;
                  /* If the actual is a conversion, get the inner expression,
                     which will be the real destination, and convert the
                     result to the type of the actual parameter.  */
                  tree gnu_actual
                    = maybe_unconstrained_array (TREE_VALUE (gnu_name_list));

                  /* If the result is a padded type, remove the padding.  */
                  if (TREE_CODE (TREE_TYPE (gnu_result)) == RECORD_TYPE
                      && TYPE_IS_PADDING_P (TREE_TYPE (gnu_result)))
                    gnu_result
                      = convert (TREE_TYPE (TYPE_FIELDS
                                            (TREE_TYPE (gnu_result))),
                                 gnu_result);

                  /* If the result is a type conversion, do it.  */
                  if (Nkind (gnat_actual) == N_Type_Conversion)
                    gnu_result
                      = convert_with_check
                        (Etype (Expression (gnat_actual)), gnu_result,
                         Do_Overflow_Check (gnat_actual),
                         Do_Range_Check (Expression (gnat_actual)),
                         Float_Truncate (gnat_actual));

                  else if (unchecked_conversion)
                    gnu_result
                      = unchecked_convert (TREE_TYPE (gnu_actual), gnu_result);
                  else
                    {
                      if (Do_Range_Check (gnat_actual))
                        gnu_result = emit_range_check (gnu_result,
                                                       Etype (gnat_actual));

                      if (! (! TREE_CONSTANT (TYPE_SIZE
                                              (TREE_TYPE (gnu_actual)))
                             && TREE_CONSTANT (TYPE_SIZE
                                               (TREE_TYPE (gnu_result)))))
                        gnu_result = convert (TREE_TYPE (gnu_actual),
                                              gnu_result);
                    }

                  set_lineno (gnat_node, 1);
                  expand_expr_stmt (build_binary_op (MODIFY_EXPR, NULL_TREE,
                                                     gnu_actual, gnu_result));
                  scalar_return_list = TREE_CHAIN (scalar_return_list);
                  gnu_name_list = TREE_CHAIN (gnu_name_list);
                }
          }
        else
          {
            set_lineno (gnat_node, 1);
            expand_expr_stmt (gnu_subprog_call);
          }

        /* Handle anything we need to assign back.  */
        for (gnu_expr = gnu_after_list;
             gnu_expr;
             gnu_expr = TREE_CHAIN (gnu_expr))
          expand_expr_stmt (build_binary_op (MODIFY_EXPR, NULL_TREE,
                                             TREE_PURPOSE (gnu_expr),
                                             TREE_VALUE (gnu_expr)));
      }
      break;

    /*************************/
    /* Chapter 7: Packages:  */
    /*************************/

    case N_Package_Declaration:
      gnat_to_code (Specification (gnat_node));
      break;

    case N_Package_Specification:

      process_decls (Visible_Declarations (gnat_node),
                     Private_Declarations (gnat_node), Empty, 1, 1);
      break;

    case N_Package_Body:

      /* If this is the body of a generic package - do nothing */
      if (Ekind (Corresponding_Spec (gnat_node)) == E_Generic_Package)
        break;

      process_decls (Declarations (gnat_node), Empty, Empty, 1, 1);

      if (Present (Handled_Statement_Sequence (gnat_node)))
        {
          gnu_block_stack = tree_cons (NULL_TREE, NULL_TREE, gnu_block_stack);
          gnat_to_code (Handled_Statement_Sequence (gnat_node));
          gnu_block_stack = TREE_CHAIN (gnu_block_stack);
        }
      break;

    /*********************************/
    /* Chapter 8: Visibility Rules:  */
    /*********************************/

    case N_Use_Package_Clause:
    case N_Use_Type_Clause:
      /* Nothing to do here - but these may appear in list of declarations */
      break;

    /***********************/
    /* Chapter 9: Tasks:   */
    /***********************/

    case N_Protected_Type_Declaration:
      break;

    case N_Single_Task_Declaration:
      gnat_to_gnu_entity (Defining_Entity (gnat_node), NULL_TREE, 1);
      break;

    /***********************************************************/
    /* Chapter 10: Program Structure and Compilation Issues:   */
    /***********************************************************/

    case N_Compilation_Unit:

      /* For a body, first process the spec if there is one. */
      if (Nkind (Unit (gnat_node)) == N_Package_Body
          || (Nkind (Unit (gnat_node)) == N_Subprogram_Body
              && ! Acts_As_Spec (gnat_node)))
        gnat_to_code (Library_Unit (gnat_node));

      process_inlined_subprograms (gnat_node);

      if (type_annotate_only && gnat_node == Cunit (Main_Unit))
        {
          elaborate_all_entities (gnat_node);

          if (Nkind (Unit (gnat_node)) == N_Subprogram_Declaration
              || Nkind (Unit (gnat_node)) == N_Generic_Package_Declaration
              || Nkind (Unit (gnat_node)) == N_Generic_Subprogram_Declaration)
            break;
        };

      process_decls (Declarations (Aux_Decls_Node (gnat_node)),
                     Empty, Empty, 1, 1);

      gnat_to_code (Unit (gnat_node));

      /* Process any pragmas following the unit.  */
      if (Present (Pragmas_After (Aux_Decls_Node (gnat_node))))
        for (gnat_temp = First (Pragmas_After (Aux_Decls_Node (gnat_node)));
             gnat_temp; gnat_temp = Next (gnat_temp))
          gnat_to_code (gnat_temp);

      /* Put all the Actions into the elaboration routine if we already had
         elaborations.  This will happen anyway if they are statements, but we
         want to force declarations there too due to order-of-elaboration
         issues.  Most should have Is_Statically_Allocated set.  If we
         have had no elaborations, we have no order-of-elaboration issue and
         don't want to create elaborations here.  */
      if (Is_Non_Empty_List (Actions (Aux_Decls_Node (gnat_node))))
        for (gnat_temp = First (Actions (Aux_Decls_Node (gnat_node)));
             Present (gnat_temp); gnat_temp = Next (gnat_temp))
          {
            if (pending_elaborations_p ())
              add_pending_elaborations (NULL_TREE,
                                        make_transform_expr (gnat_temp));
            else
              gnat_to_code (gnat_temp);
          }

      /* Generate elaboration code for this unit, if necessary, and
         say whether we did or not.  */
      Set_Has_No_Elaboration_Code
        (gnat_node,
         build_unit_elab
         (Defining_Entity (Unit (gnat_node)),
          Nkind (Unit (gnat_node)) == N_Package_Body
          || Nkind (Unit (gnat_node)) == N_Subprogram_Body,
          get_pending_elaborations ()));

      break;

    case N_Subprogram_Body_Stub:
    case N_Package_Body_Stub:
    case N_Protected_Body_Stub:
    case N_Task_Body_Stub:
      /* Simply process whatever unit is being inserted.  */
      gnat_to_code (Unit (Library_Unit (gnat_node)));
      break;

    case N_Subunit:
      gnat_to_code (Proper_Body (gnat_node));
      break;

    /***************************/
    /* Chapter 11: Exceptions: */
    /***************************/

    case N_Handled_Sequence_Of_Statements:
      /* If there are exception handlers, start a new binding level that
         we can exit (since each exception handler will do so).  Then
         declare a variable to save the old __gnat_jmpbuf value and a
         variable for our jmpbuf.  Call setjmp and handle each of the
         possible exceptions if it returns one. */

      if (! type_annotate_only && Present (Exception_Handlers (gnat_node)))
        {
          tree gnu_jmpsave_decl = 0;
          tree gnu_jmpbuf_decl = 0;
          tree gnu_cleanup_call = 0;
          tree gnu_cleanup_decl;

          pushlevel (0);
          expand_start_bindings (1);

          if (! Zero_Cost_Handling (gnat_node))
            {
              gnu_jmpsave_decl
                = create_var_decl (get_identifier ("JMPBUF_SAVE"), NULL_TREE,
                                   jmpbuf_ptr_type,
                                   build_call_0_expr (get_jmpbuf_decl),
                                   0, 0, 0, 0, 0);

              gnu_jmpbuf_decl = create_var_decl (get_identifier ("JMP_BUF"),
                                                 NULL_TREE, jmpbuf_type,
                                                 NULL_TREE, 0, 0, 0, 0,
                                                 0);
              TREE_VALUE (gnu_block_stack) = gnu_jmpbuf_decl;
            }

          /* See if we are to call a function when exiting this block.  */
          if (Present (At_End_Proc (gnat_node)))
            {
              gnu_cleanup_call
                = build_call_0_expr (gnat_to_gnu (At_End_Proc (gnat_node)));

              gnu_cleanup_decl
                = create_var_decl (get_identifier ("CLEANUP"), NULL_TREE,
                                   integer_type_node, NULL_TREE, 0, 0, 0, 0,
                                   0);

              expand_decl_cleanup (gnu_cleanup_decl, gnu_cleanup_call);
            }

          if (! Zero_Cost_Handling (gnat_node))
            {
              /* When we exit this block, restore the saved value.  */
              expand_decl_cleanup (gnu_jmpsave_decl,
                                   build_call_1_expr (set_jmpbuf_decl,
                                                      gnu_jmpsave_decl));

              /* Call setjmp and handle exceptions if it returns one.  */
              set_lineno (gnat_node, 1);
              expand_start_cond
                (build_call_1_expr (setjmp_decl,
                                    build_unary_op (ADDR_EXPR, NULL_TREE,
                                                    gnu_jmpbuf_decl)),
                 0);

              /* Restore our incoming longjmp value before we do anything.  */
              expand_expr_stmt (build_call_1_expr (set_jmpbuf_decl,
                                                   gnu_jmpsave_decl));

              pushlevel (0);
              expand_start_bindings (0);

              gnu_except_ptr_stack
                = tree_cons (NULL_TREE,
                             create_var_decl
                             (get_identifier ("EXCEPT_PTR"), NULL_TREE,
                              build_pointer_type (except_type_node),
                              build_call_0_expr (get_excptr_decl),
                              0, 0, 0, 0, 0),
                             gnu_except_ptr_stack);

              /* Generate code for each exception handler.  The code at
                 N_Exception_Handler below does the real work. Note that
                 we ignore the dummy exception handler for the identifier
                 case, this is used only by the front end */
              if (Present (Exception_Handlers (gnat_node)))
                for (gnat_temp
                     = First_Non_Pragma (Exception_Handlers (gnat_node));
                     Present (gnat_temp);
                     gnat_temp = Next_Non_Pragma (gnat_temp))
                  gnat_to_code (gnat_temp);

              /* If none of the exception handlers did anything, re-raise
                 but do not defer abortion.  */
              set_lineno (gnat_node, 1);
              expand_expr_stmt
                (build_call_1_expr (raise_nodefer_decl,
                                    TREE_VALUE (gnu_except_ptr_stack)));

              gnu_except_ptr_stack = TREE_CHAIN (gnu_except_ptr_stack);
              expand_end_bindings (getdecls (), kept_level_p (), 0);
              poplevel (kept_level_p (), 1, 0);

              /* End the "if" on setjmp.  Note that we have arranged things so
                 control never returns here.  */
              expand_end_cond ();

              /* This is now immediately before the body proper.  Set
                 our jmp_buf as the current buffer.  */
              expand_expr_stmt
                (build_call_1_expr (set_jmpbuf_decl,
                                    build_unary_op (ADDR_EXPR, NULL_TREE,
                                                    gnu_jmpbuf_decl)));
            }
        }

      /* If there are no exception handlers, we must not have an at end
         cleanup identifier, since the cleanup identifier should always
         generate a corresponding exception handler. */
      else if (! type_annotate_only && Present (At_End_Proc (gnat_node)))
        gigi_abort (335);

      /* Generate code and declarations for the prefix of this block, 
         if any.  */
      if (Present (First_Real_Statement (gnat_node)))
        process_decls (Statements (gnat_node), Empty,
                       First_Real_Statement (gnat_node), 1, 1);

      /* Generate code for each statement in the block.  */
      for (gnat_temp = (Present (First_Real_Statement (gnat_node))
                        ? First_Real_Statement (gnat_node)
                        : First (Statements (gnat_node)));
           Present (gnat_temp); gnat_temp = Next (gnat_temp))
        gnat_to_code (gnat_temp);

      /* For zero-cost exceptions, exit the block and then compile
         the handlers.  */
      if (! type_annotate_only && Zero_Cost_Handling (gnat_node)
          && Present (Exception_Handlers (gnat_node)))
        {
          expand_exit_something ();
          gnu_except_ptr_stack
            = tree_cons (NULL_TREE, error_mark_node, gnu_except_ptr_stack);

          for (gnat_temp = First_Non_Pragma (Exception_Handlers (gnat_node));
               Present (gnat_temp);
               gnat_temp = Next_Non_Pragma (gnat_temp))
            gnat_to_code (gnat_temp);

          gnu_except_ptr_stack = TREE_CHAIN (gnu_except_ptr_stack);
        }

      /* If we have handlers, close the block we made.  */
      if (! type_annotate_only && Present (Exception_Handlers (gnat_node)))
        {
          expand_end_bindings (getdecls (), kept_level_p (), 0);
          poplevel (kept_level_p (), 1, 0);
        }

      break;

    case N_Exception_Handler:
      if (! Zero_Cost_Handling (gnat_node))
        {
          /* Unless this is "Others" or the special "Non-Ada" exception
             for Ada, make an "if" statement to select the proper
             exceptions.  For "Others", exclude exceptions where
             Handled_By_Others is nonzero unless the All_Others flag is set.
             For "Non-ada", accept an exception if "Lang" is 'V'.  */
          tree gnu_choice = integer_zero_node;

          for (gnat_temp = First (Exception_Choices (gnat_node));
               gnat_temp; gnat_temp = Next (gnat_temp))
            {
              tree this_choice;

              if (Nkind (gnat_temp) == N_Others_Choice)
                {
                  if (All_Others (gnat_temp))
                    this_choice = integer_one_node;
                  else
                    this_choice
                      = build_binary_op
                        (EQ_EXPR, integer_type_node,
                       convert
                       (integer_type_node,
                        build_component_ref
                        (build_unary_op
                         (INDIRECT_REF, NULL_TREE,
                          TREE_VALUE (gnu_except_ptr_stack)),
                         get_identifier ("not_handled_by_others"), NULL_TREE)),
                         integer_zero_node);
                }

              else if (Nkind (gnat_temp) == N_Identifier
                       || Nkind (gnat_temp) == N_Expanded_Name)
                {
                  /* ??? Note that we have to use gnat_to_gnu_entity here
                     since the type of the exception will be wrong in the
                     VMS case and that's exactly what this test is for.  */
                  gnu_expr
                    = gnat_to_gnu_entity (Entity (gnat_temp), NULL_TREE, 0);

                  /* If this was a VMS exception, check import_code
                     against the value of the exception.  */
                  if (TREE_CODE (TREE_TYPE (gnu_expr)) == INTEGER_TYPE)
                    this_choice
                      = build_binary_op
                        (EQ_EXPR, integer_type_node,
                         build_component_ref
                         (build_unary_op
                          (INDIRECT_REF, NULL_TREE,
                           TREE_VALUE (gnu_except_ptr_stack)),
                          get_identifier ("import_code"), NULL_TREE),
                         gnu_expr);
                  else
                    this_choice
                      = build_binary_op 
                        (EQ_EXPR, integer_type_node,
                         TREE_VALUE (gnu_except_ptr_stack),
                         convert
                         (TREE_TYPE (TREE_VALUE (gnu_except_ptr_stack)), 
                          build_unary_op (ADDR_EXPR, NULL_TREE, gnu_expr)));

                  /* If this is the distinguished exception "Non_Ada_Error"
                     (and we are in VMS mode), also allow a non-Ada
                     exception (a VMS condition) to match.  */
                  if (Is_Non_Ada_Error (Entity (gnat_temp)))
                    {
                      tree gnu_comp
                        = build_component_ref
                          (build_unary_op
                           (INDIRECT_REF, NULL_TREE,
                            TREE_VALUE (gnu_except_ptr_stack)),
                           get_identifier ("lang"), NULL_TREE);

                      this_choice
                        = build_binary_op
                        (TRUTH_ORIF_EXPR, integer_type_node,
                         build_binary_op
                         (EQ_EXPR, integer_type_node, gnu_comp,
                          convert (TREE_TYPE (gnu_comp),
                                   build_int_2 ('V', 0))),
                         this_choice);
                    }
                }
              else
                gigi_abort (318);

              gnu_choice = build_binary_op (TRUTH_ORIF_EXPR, integer_type_node,
                                            gnu_choice, this_choice);
            }

          set_lineno (gnat_node, 1);

          expand_start_cond (gnu_choice, 0);
        }

      for (gnat_temp = First (Statements (gnat_node));
           gnat_temp; gnat_temp = Next (gnat_temp))
        gnat_to_code (gnat_temp);

      /* At the end of the handler, exit the block.  We made this block
         in N_Handled_Sequence_Of_Statements.  */
      expand_exit_something ();

      if (! Zero_Cost_Handling (gnat_node))
        expand_end_cond ();

      break;

    /*******************************/
    /* Chapter 12: Generic Units:  */
    /*******************************/

    case N_Generic_Function_Renaming_Declaration:
    case N_Generic_Package_Renaming_Declaration:
    case N_Generic_Procedure_Renaming_Declaration:
    case N_Generic_Package_Declaration:
    case N_Generic_Subprogram_Declaration:
    case N_Package_Instantiation:
    case N_Procedure_Instantiation:
    case N_Function_Instantiation:
      /* These nodes can appear on a declaration list but there is nothing to
         to be done with them.  */
      break;


    /***************************************************/
    /* Chapter 13: Representation Clauses and          */
    /*             Implementation-Dependent Features:  */
    /***************************************************/

    case N_Attribute_Definition_Clause:

      /* The only one we need deal with is for 'Address.  For the others, SEM
         puts the information elsewhere.  We need only deal with 'Address
         if the object has a Freeze_Node (which it never will currently).  */
      if (Get_Attribute_Id (Chars (gnat_node)) != Attr_Address
          || No (Freeze_Node (Entity (Name (gnat_node)))))
        break;

      /* Get the value to use as the address and save it as the
         equivalent for GNAT_TEMP.  When the object is frozen,
         gnat_to_gnu_entity will do the right thing. */
      gnu_expr = gnat_to_gnu (Expression (gnat_node));
      save_gnu_tree (Entity (Name (gnat_node)), gnu_expr, 1);
      break;

    case N_Enumeration_Representation_Clause:
    case N_Record_Representation_Clause:
    case N_At_Clause:
      /* We do nothing with these.  SEM puts the information elsewhere.  */
      break;

    case N_Code_Statement:
      if (! type_annotate_only)
        {
          tree gnu_template = gnat_to_gnu (Asm_Template (gnat_node));
          tree gnu_input_list = 0, gnu_output_list = 0, gnu_orig_out_list = 0;
          tree gnu_clobber_list = 0;
          char *clobber;

          /* First process inputs, then outputs, then clobbers.  */
          Setup_Asm_Inputs (gnat_node);
          while (Present (gnat_temp = Asm_Input_Value ()))
            {
              tree gnu_value = gnat_to_gnu (gnat_temp);
              tree gnu_constr = build_tree_list (NULL_TREE, gnat_to_gnu
                                                 (Asm_Input_Constraint ()));

              gnu_input_list 
                = tree_cons (gnu_constr, gnu_value, gnu_input_list);
              Next_Asm_Input ();
            }

          Setup_Asm_Outputs (gnat_node);
          while (Present (gnat_temp = Asm_Output_Variable ()))
            {
              tree gnu_value = gnat_to_gnu (gnat_temp);
              tree gnu_constr = build_tree_list (NULL_TREE, gnat_to_gnu
                                                 (Asm_Output_Constraint ()));

              gnu_orig_out_list
                = tree_cons (gnu_constr, gnu_value, gnu_orig_out_list);
              gnu_output_list
                = tree_cons (gnu_constr, gnu_value, gnu_output_list);
              Next_Asm_Output ();
            }

          Clobber_Setup (gnat_node);
          while ((clobber = Clobber_Get_Next ()) != 0)
            gnu_clobber_list
              = tree_cons (NULL_TREE, 
                           build_string (strlen (clobber) + 1, clobber),
                           gnu_clobber_list);

          expand_asm_operands (gnu_template, nreverse (gnu_output_list),
                               nreverse (gnu_input_list), gnu_clobber_list,
                               Is_Asm_Volatile (gnat_node),
                               input_filename, lineno);

          /* Copy all the intermediate outputs into the specified outputs.  */
          for (; gnu_output_list;
               (gnu_output_list = TREE_CHAIN (gnu_output_list),
                gnu_orig_out_list = TREE_CHAIN (gnu_orig_out_list)))
            if (TREE_VALUE (gnu_orig_out_list) != TREE_VALUE (gnu_output_list))
              {
                expand_expr_stmt
                  (build_binary_op (MODIFY_EXPR, NULL_TREE,
                                    TREE_VALUE (gnu_orig_out_list),
                                    TREE_VALUE (gnu_output_list)));
                free_temp_slots ();
              }
        }
      break;

    /***************************************************/
    /* Added Nodes                                     */
    /***************************************************/

    case N_Freeze_Entity:
      process_freeze_entity (gnat_node);
      process_decls (Actions (gnat_node), Empty, Empty, 1, 1);
      break;

    case N_Itype_Reference:
      if (! present_gnu_tree (Itype (gnat_node)))
        process_type (Itype (gnat_node));
      break;

    case N_Free_Statement:
      if (! type_annotate_only)
        {
          tree gnu_ptr = gnat_to_gnu (Expression (gnat_node));
          tree gnu_obj_type;
          tree gnu_obj_size;
          int align;

          /* If this is an unconstrained array, we know the object must
             have been allocated with the template in front of the object.
             So pass the template address, but get the total size.  Do this
             by converting to a thin pointer.  */
          if (TYPE_FAT_POINTER_P (TREE_TYPE (gnu_ptr)))
            gnu_ptr
              = convert (build_pointer_type
                         (TYPE_OBJECT_RECORD_TYPE
                          (TYPE_UNCONSTRAINED_ARRAY (TREE_TYPE (gnu_ptr)))),
                         gnu_ptr);

          gnu_obj_type = TREE_TYPE (TREE_TYPE (gnu_ptr));
          gnu_obj_size = TYPE_SIZE_UNIT (gnu_obj_type);
          align = TYPE_ALIGN (gnu_obj_type);

          if (TREE_CODE (gnu_obj_type) == RECORD_TYPE
              && TYPE_CONTAINS_TEMPLATE_P (gnu_obj_type))
            {
              tree gnu_char_ptr_type = build_pointer_type (char_type_node);
              tree gnu_pos = byte_position (TYPE_FIELDS (gnu_obj_type));
              tree gnu_byte_offset
                = convert (gnu_char_ptr_type,
                           size_diffop (size_zero_node, gnu_pos));

              gnu_ptr = convert (gnu_char_ptr_type, gnu_ptr);
              gnu_ptr = build_binary_op (MINUS_EXPR, gnu_char_ptr_type,
                                         gnu_ptr, gnu_byte_offset);
            }

          set_lineno (gnat_node, 1);
          expand_expr_stmt
            (build_call_alloc_dealloc (gnu_ptr, gnu_obj_size, align,
                                       Procedure_To_Call (gnat_node),
                                       Storage_Pool (gnat_node)));
        }
      break;

    case N_Raise_Constraint_Error:
    case N_Raise_Program_Error:
    case N_Raise_Storage_Error:

      if (type_annotate_only)
        break;

      gnu_result_type = get_unpadded_type (Etype (gnat_node));
      gnu_result
        = build_call_raise
          (Nkind (gnat_node) == N_Raise_Constraint_Error
           ? raise_constraint_error_decl
           : Nkind (gnat_node) == N_Raise_Program_Error
           ? raise_program_error_decl : raise_storage_error_decl);

      /* If the type is VOID, this is a statement, so we need to 
         generate the code for the call.  Handle a Condition, if there
         is one.  */
      if (TREE_CODE (gnu_result_type) == VOID_TYPE)
        {
          set_lineno (gnat_node, 1);

          if (Present (Condition (gnat_node)))
            expand_start_cond (gnat_to_gnu (Condition (gnat_node)), 0);

          expand_expr_stmt (gnu_result);
          if (Present (Condition (gnat_node)))
            expand_end_cond ();
          gnu_result = error_mark_node;
        }
      else
        gnu_result = build1 (NULL_EXPR, gnu_result_type, gnu_result);
      break;

    /* Nothing to do, since front end does all validation using the
       values that Gigi back-annotates.  */
    case N_Validate_Unchecked_Conversion:
      break;

    case N_Raise_Statement:
    case N_Function_Specification:
    case N_Procedure_Specification:
    case N_Op_Concat:
    case N_Component_Association:
    case N_Task_Body:
    default:
      if (! type_annotate_only)
        gigi_abort (321);
    }

  /* If the result is a constant that overflows, raise constraint error.  */
  if (TREE_CODE (gnu_result) == INTEGER_CST
      && TREE_CONSTANT_OVERFLOW (gnu_result))
    {
      post_error ("Constraint_Error will be raised at run-time?", gnat_node);

      gnu_result
        = build1 (NULL_EXPR, gnu_result_type,
                  build_call_raise (raise_constraint_error_decl));
    }

  /* If our result has side-effects and is of an unconstrained type,
     make a SAVE_EXPR so that we can be sure it will only be referenced
     once.  Note we must do this before any conversions.  */
  if (TREE_SIDE_EFFECTS (gnu_result)
      && (TREE_CODE (gnu_result_type) == UNCONSTRAINED_ARRAY_TYPE
          || (TREE_CODE (TYPE_SIZE (gnu_result_type)) != INTEGER_CST
              && contains_placeholder_p (TYPE_SIZE (gnu_result_type)))))
    gnu_result = gnat_stabilize_reference (gnu_result, 0);

  /* Now convert the result to the proper type.  If the type is void or if
     we have no result, return error_mark_node to show we have no result.
     If the type of the result is correct or if we have a label (which doesn't
     have any well-defined type), return our result.  Also don't do the
     conversion if the "desired" type involves a PLACEHOLDER_EXPR in its size
     since those are the cases where the front end may have the type wrong due
     to "instantiating" the unconstrained record with discriminant values
     or if this is a FIELD_DECL.  If this is the Name of an assignment
     statement or a parameter of a procedure call, return what we have since
     the RHS has to be converted to our type there in that case, unless
     GNU_RESULT_TYPE has a simpler size.  Similarly, if the two types are
     record types with the same name, the expression type has integral mode,
     and GNU_RESULT_TYPE BLKmode, don't convert.  This will be the case when
     we are converting from a packable type to its actual type and we need
     those conversions to be NOPs in order for assignments into these types to
     work properly if the inner object is a bitfield and hence can't have
     its address taken.  Finally, don't convert integral types that are the
     operand of an unchecked conversion since we need to ignore those
     conversions (for 'Valid).  Otherwise, convert the result to the proper
     type.  */

  if (Present (Parent (gnat_node))
      && ((Nkind (Parent (gnat_node)) == N_Assignment_Statement
           && Name (Parent (gnat_node)) == gnat_node)
          || (Nkind (Parent (gnat_node)) == N_Procedure_Call_Statement
              && Name (Parent (gnat_node)) != gnat_node)
          || (Nkind (Parent (gnat_node)) == N_Unchecked_Type_Conversion
              && ! AGGREGATE_TYPE_P (gnu_result_type)
              && ! AGGREGATE_TYPE_P (TREE_TYPE (gnu_result)))
          || Nkind (Parent (gnat_node)) == N_Parameter_Association)
      && ! (TYPE_SIZE (gnu_result_type) != 0
            && TYPE_SIZE (TREE_TYPE (gnu_result)) != 0
            && (AGGREGATE_TYPE_P (gnu_result_type)
                == AGGREGATE_TYPE_P (TREE_TYPE (gnu_result)))
            && ((TREE_CODE (TYPE_SIZE (gnu_result_type)) == INTEGER_CST
                 && (TREE_CODE (TYPE_SIZE (TREE_TYPE (gnu_result)))
                     != INTEGER_CST))
                || (TREE_CODE (TYPE_SIZE (gnu_result_type)) != INTEGER_CST
                    && (TREE_CODE (TYPE_SIZE (TREE_TYPE (gnu_result)))
                        != INTEGER_CST)
                    && ! (contains_placeholder_p (TYPE_SIZE (gnu_result_type)))
                    && (contains_placeholder_p
                        (TYPE_SIZE (TREE_TYPE (gnu_result))))))
            && ! (TREE_CODE (gnu_result_type) == RECORD_TYPE
                  && TYPE_LEFT_JUSTIFIED_MODULAR_P (gnu_result_type))))
    {
      /* In this case remove padding only if the inner object is of
         self-referential size: in that case it must be an object of
         unconstrained type with a default discriminant.  In other cases,
         we want to avoid copying too much data.  */
      if (TREE_CODE (TREE_TYPE (gnu_result)) == RECORD_TYPE
          && TYPE_IS_PADDING_P (TREE_TYPE (gnu_result))
          && contains_placeholder_p (TYPE_SIZE
                                     (TREE_TYPE (TYPE_FIELDS
                                                 (TREE_TYPE (gnu_result))))))
        gnu_result = convert (TREE_TYPE (TYPE_FIELDS (TREE_TYPE (gnu_result))),
                              gnu_result);
    }

  else if (TREE_CODE (gnu_result) == LABEL_DECL
           || TREE_CODE (gnu_result) == FIELD_DECL
           || TREE_CODE (gnu_result) == ERROR_MARK
           || (TYPE_SIZE (gnu_result_type) != 0
               && TREE_CODE (TYPE_SIZE (gnu_result_type)) != INTEGER_CST
               && TREE_CODE (gnu_result) != INDIRECT_REF
               && contains_placeholder_p (TYPE_SIZE (gnu_result_type)))
           || ((TYPE_NAME (gnu_result_type)
                == TYPE_NAME (TREE_TYPE (gnu_result)))
               && TREE_CODE (gnu_result_type) == RECORD_TYPE
               && TREE_CODE (TREE_TYPE (gnu_result)) == RECORD_TYPE
               && TYPE_MODE (gnu_result_type) == BLKmode
               && (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (gnu_result)))
                   == MODE_INT)))
    {
      /* Remove any padding record, but do nothing more in this case.  */
      if (TREE_CODE (TREE_TYPE (gnu_result)) == RECORD_TYPE
          && TYPE_IS_PADDING_P (TREE_TYPE (gnu_result)))
        gnu_result = convert (TREE_TYPE (TYPE_FIELDS (TREE_TYPE (gnu_result))),
                              gnu_result);
    }

  else if (gnu_result == error_mark_node
           || gnu_result_type == void_type_node)
    gnu_result =  error_mark_node;
  else if (gnu_result_type != TREE_TYPE (gnu_result))
    gnu_result = convert (gnu_result_type, gnu_result);

  /* We don't need any NOP_EXPR or NON_LVALUE_EXPR on GNU_RESULT.  */
  while ((TREE_CODE (gnu_result) == NOP_EXPR
          || TREE_CODE (gnu_result) == NON_LVALUE_EXPR)
         && TREE_TYPE (TREE_OPERAND (gnu_result, 0)) == TREE_TYPE (gnu_result))
    gnu_result = TREE_OPERAND (gnu_result, 0);

  return gnu_result;
}
\f
/* Force references to each of the entities in packages GNAT_NODE with's
   so that the debugging information for all of them are identical
   in all clients.  Operate recursively on anything it with's, but check
   that we aren't elaborating something more than once.  */

/* The reason for this routine's existence is two-fold.
   First, with some debugging formats, notably MDEBUG on SGI
   IRIX, the linker will remove duplicate debugging information if two
   clients have identical debugguing information.  With the normal scheme
   of elaboration, this does not usually occur, since entities in with'ed
   packages are elaborated on demand, and if clients have different usage
   patterns, the normal case, then the order and selection of entities
   will differ.  In most cases however, it seems that linkers do not know
   how to eliminate duplicate debugging information, even if it is 
   identical, so the use of this routine would increase the total amount
   of debugging information in the final executable.

   Second, this routine is called in type_annotate mode, to compute DDA
   information for types in withed units, for ASIS use  */

static void
elaborate_all_entities (gnat_node)
     Node_Id gnat_node;
{
  Entity_Id gnat_with_clause, gnat_entity;

  save_gnu_tree (gnat_node, integer_zero_node, 1);

  /* Save entities in all context units. A body may have an implicit_with
     on its own spec, if the context includes a child unit, so don't save
     the spec twice.  */

  for (gnat_with_clause = First (Context_Items (gnat_node));
       Present (gnat_with_clause);
       gnat_with_clause = Next (gnat_with_clause))
    if (Nkind (gnat_with_clause) == N_With_Clause
        && ! present_gnu_tree (Library_Unit (gnat_with_clause))
        && Library_Unit (gnat_with_clause) != Library_Unit (Cunit (Main_Unit)))
      {
        elaborate_all_entities (Library_Unit (gnat_with_clause));

        if (Ekind (Entity (Name (gnat_with_clause))) == E_Package)
          for (gnat_entity = First_Entity (Entity (Name (gnat_with_clause)));
               Present (gnat_entity);
               gnat_entity = Next_Entity (gnat_entity))
            if (Is_Public (gnat_entity)
                && Convention (gnat_entity) != Convention_Intrinsic
                && Ekind (gnat_entity) != E_Package
                && Ekind (gnat_entity) != E_Package_Body
                && Ekind (gnat_entity) != E_Operator
                && ! (IN (Ekind (gnat_entity), Type_Kind)
                      && ! Is_Frozen (gnat_entity))
                && ! ((Ekind (gnat_entity) == E_Procedure
                       || Ekind (gnat_entity) == E_Function)
                      && Is_Intrinsic_Subprogram (gnat_entity))
                && ! IN (Ekind (gnat_entity), Named_Kind)
                && ! IN (Ekind (gnat_entity), Generic_Unit_Kind))
              gnat_to_gnu_entity (gnat_entity, NULL_TREE, 0);
      }

  if (Nkind (Unit (gnat_node)) == N_Package_Body && type_annotate_only)
    elaborate_all_entities (Library_Unit (gnat_node));
}
\f
/* Do the processing of N_Freeze_Entity, GNAT_NODE.  */

static void
process_freeze_entity (gnat_node)
     Node_Id gnat_node;
{
  Entity_Id gnat_entity = Entity (gnat_node);
  tree gnu_old;
  tree gnu_new;
  tree gnu_init
    = (Nkind (Declaration_Node (gnat_entity)) == N_Object_Declaration
       && present_gnu_tree (Declaration_Node (gnat_entity)))
      ? get_gnu_tree (Declaration_Node (gnat_entity)) : NULL_TREE;

  /* If this is a package, need to generate code for the package.  */
  if (Ekind (gnat_entity) == E_Package)
    {
      insert_code_for
        (Parent (Corresponding_Body
                 (Parent (Declaration_Node (gnat_entity)))));
      return;
    }

  /* Check for old definition after the above call.  This Freeze_Node
     might be for one its Itypes.  */
  gnu_old
    = present_gnu_tree (gnat_entity) ? get_gnu_tree (gnat_entity) : 0;

  /* If this entity has an Address representation clause, GNU_OLD is the
     address, so discard it here.  */
  if (Present (Address_Clause (gnat_entity)))
    gnu_old = 0;

  /* Don't do anything for class-wide types they are always
     transformed into their root type.  */
  if (Ekind (gnat_entity) == E_Class_Wide_Type
      || (Ekind (gnat_entity) == E_Class_Wide_Subtype
          && Present (Equivalent_Type (gnat_entity))))
    return;

  /* If we have a non-dummy type old tree, we have nothing to do.   Unless
     this is the public view of a private type whose full view was not
     delayed, this node was never delayed as it should have been.
     Also allow this to happen for concurrent types since we may have
     frozen both the Corresponding_Record_Type and this type.  */
  if (gnu_old != 0
      && ! (TREE_CODE (gnu_old) == TYPE_DECL
            && TYPE_IS_DUMMY_P (TREE_TYPE (gnu_old))))
    {
      if (IN (Ekind (gnat_entity), Incomplete_Or_Private_Kind)
          && Present (Full_View (gnat_entity))
          && No (Freeze_Node (Full_View (gnat_entity))))
        return;
      else if (Is_Concurrent_Type (gnat_entity))
        return;
      else
        gigi_abort (320);
    }

  /* Reset the saved tree, if any, and elaborate the object or type for real.
     If there is a full declaration, elaborate it and copy the type to
     GNAT_ENTITY.  Likewise if this is the record subtype corresponding to
     a class wide type or subtype.  */
  if (gnu_old != 0)
    {
      save_gnu_tree (gnat_entity, NULL_TREE, 0);
      if (IN (Ekind (gnat_entity), Incomplete_Or_Private_Kind)
          && Present (Full_View (gnat_entity))
          && present_gnu_tree (Full_View (gnat_entity)))
        save_gnu_tree (Full_View (gnat_entity), NULL_TREE, 0);
      if (Present (Class_Wide_Type (gnat_entity))
          && Class_Wide_Type (gnat_entity) != gnat_entity)
        save_gnu_tree (Class_Wide_Type (gnat_entity), NULL_TREE, 0);
    }

  if (IN (Ekind (gnat_entity), Incomplete_Or_Private_Kind)
      && Present (Full_View (gnat_entity)))
    {
      gnu_new = gnat_to_gnu_entity (Full_View (gnat_entity), NULL_TREE, 1);

      /* The above call may have defined this entity (the simplest example
         of this is when we have a private enumeral type since the bounds
         will have the public view.  */
      if (! present_gnu_tree (gnat_entity))
        save_gnu_tree (gnat_entity, gnu_new, 0);
      if (Present (Class_Wide_Type (gnat_entity))
          && Class_Wide_Type (gnat_entity) != gnat_entity)
        save_gnu_tree (Class_Wide_Type (gnat_entity), gnu_new, 0);
    }
  else
    gnu_new = gnat_to_gnu_entity (gnat_entity, gnu_init, 1);

  /* If we've made any pointers to the old version of this type, we
     have to update them.  Also copy the name of the old object to
     the new one.  */

  if (gnu_old != 0)
    {
      DECL_NAME (gnu_new) = DECL_NAME (gnu_old);
      update_pointer_to (TYPE_MAIN_VARIANT (TREE_TYPE (gnu_old)),
                         TREE_TYPE (gnu_new));
    }
}
\f
/* Process the list of inlined subprograms of GNAT_NODE, which is an
   N_Compilation_Unit.  */

static void
process_inlined_subprograms (gnat_node)
     Node_Id gnat_node;
{
  Entity_Id gnat_entity;
  Node_Id gnat_body;

  /* If we can inline, generate RTL for all the inlined subprograms.
     Define the entity first so we set DECL_EXTERNAL.  */
  if (optimize > 0 && ! flag_no_inline)
    for (gnat_entity = First_Inlined_Subprogram (gnat_node);
         Present (gnat_entity);
         gnat_entity = Next_Inlined_Subprogram (gnat_entity))
      {
        gnat_body = Parent (Declaration_Node (gnat_entity));

        if (Nkind (gnat_body) != N_Subprogram_Body)
          {
            /* ??? This really should always be Present.  */
            if (No (Corresponding_Body (gnat_body)))
              continue;

            gnat_body
              = Parent (Declaration_Node (Corresponding_Body (gnat_body)));
          }

        if (Present (gnat_body))
          {
            gnat_to_gnu_entity (gnat_entity, NULL_TREE, 0);
            gnat_to_code (gnat_body);
          }
      }
}
\f
/* Elaborate decls in the lists GNAT_DECLS and GNAT_DECLS2, if present.
   We make two passes, one to elaborate anything other than bodies (but
   we declare a function if there was no spec).  The second pass
   elaborates the bodies.

   GNAT_END_LIST gives the element in the list past the end.  Normally,
   this is Empty, but can be First_Real_Statement for a
   Handled_Sequence_Of_Statements.

   We make a complete pass through both lists if PASS1P is true, then make
   the second pass over both lists if PASS2P is true.  The lists usually
   correspond to the public and private parts of a package.  */

static void
process_decls (gnat_decls, gnat_decls2, gnat_end_list, pass1p, pass2p)
     List_Id gnat_decls, gnat_decls2;
     Node_Id gnat_end_list;
     int pass1p, pass2p;
{
  List_Id gnat_decl_array[2];
  Node_Id gnat_decl;
  int i;

  gnat_decl_array[0] = gnat_decls, gnat_decl_array[1] = gnat_decls2;

  if (pass1p)
    for (i = 0; i <= 1; i++)
      if (Present (gnat_decl_array[i]))
        for (gnat_decl = First (gnat_decl_array[i]);
             gnat_decl != gnat_end_list; gnat_decl = Next (gnat_decl))
          {
            set_lineno (gnat_decl, 0);

            /* For package specs, we recurse inside the declarations,
               thus taking the two pass approach inside the boundary.  */
            if (Nkind (gnat_decl) == N_Package_Declaration
                && (Nkind (Specification (gnat_decl)
                           == N_Package_Specification)))
              process_decls (Visible_Declarations (Specification (gnat_decl)),
                             Private_Declarations (Specification (gnat_decl)),
                             Empty, 1, 0);

            /* Similarly for any declarations in the actions of a
               freeze node.  */
            else if (Nkind (gnat_decl) == N_Freeze_Entity)
              {
                process_freeze_entity (gnat_decl);
                process_decls (Actions (gnat_decl), Empty, Empty, 1, 0);
              }

            /* Package bodies with freeze nodes get their elaboration deferred
               until the freeze node, but the code must be placed in the right
               place, so record the code position now.  */
            else if (Nkind (gnat_decl) == N_Package_Body
                     && Present (Freeze_Node (Corresponding_Spec (gnat_decl))))
              record_code_position (gnat_decl);

            else if (Nkind (gnat_decl) == N_Package_Body_Stub
                     && Present (Library_Unit (gnat_decl))
                     && Present (Freeze_Node
                                 (Corresponding_Spec
                                  (Proper_Body (Unit
                                                (Library_Unit (gnat_decl)))))))
              record_code_position
                (Proper_Body (Unit (Library_Unit (gnat_decl))));

            /* We defer most subprogram bodies to the second pass.
               However, Init_Proc subprograms cannot be defered, but luckily
               don't need to be. */
            else if ((Nkind (gnat_decl) == N_Subprogram_Body
                      && (Chars (Defining_Entity (gnat_decl))
                          != Name_uInit_Proc)))
              {
                if (Acts_As_Spec (gnat_decl))
                  {
                    Node_Id gnat_subprog_id = Defining_Entity (gnat_decl);

                    if (Ekind (gnat_subprog_id) != E_Generic_Procedure
                        && Ekind (gnat_subprog_id) != E_Generic_Function)
                      gnat_to_gnu_entity (gnat_subprog_id, NULL_TREE, 1);
                  }
              }
            /* For bodies and stubs that act as their own specs, the entity
               itself must be elaborated in the first pass, because it may
               be used in other declarations. */
            else if (Nkind (gnat_decl) == N_Subprogram_Body_Stub)
              {
                  Node_Id gnat_subprog_id =
                     Defining_Entity (Specification (gnat_decl));

                    if    (Ekind (gnat_subprog_id) != E_Subprogram_Body
                        && Ekind (gnat_subprog_id) != E_Generic_Procedure
                        && Ekind (gnat_subprog_id) != E_Generic_Function)
                      gnat_to_gnu_entity (gnat_subprog_id, NULL_TREE, 1);
               }

            /* Concurrent stubs stand for the corresponding subprogram bodies,
               which are deferred like other bodies.  */
              else if (Nkind (gnat_decl) == N_Task_Body_Stub
                       || Nkind (gnat_decl) == N_Protected_Body_Stub)
                ;

            else
              gnat_to_code (gnat_decl);
          }

  /* Here we elaborate everything we deferred above except for package bodies,
     which are elaborated at their freeze nodes.  Note that we must also
     go inside things (package specs and freeze nodes) the first pass did.  */
  if (pass2p)
    for (i = 0; i <= 1; i++)
      if (Present (gnat_decl_array[i]))
        for (gnat_decl = First (gnat_decl_array[i]);
             gnat_decl != gnat_end_list; gnat_decl = Next (gnat_decl))
          {
            if ((Nkind (gnat_decl) == N_Subprogram_Body
                 && (Chars (Defining_Entity (gnat_decl))
                     != Name_uInit_Proc))
                || Nkind (gnat_decl) == N_Subprogram_Body_Stub
                || Nkind (gnat_decl) == N_Task_Body_Stub
                || Nkind (gnat_decl) == N_Protected_Body_Stub)
              gnat_to_code (gnat_decl);

            else if (Nkind (gnat_decl) == N_Package_Declaration
                     && (Nkind (Specification (gnat_decl)
                                == N_Package_Specification)))
              process_decls (Visible_Declarations (Specification (gnat_decl)),
                             Private_Declarations (Specification (gnat_decl)),
                             Empty, 0, 1);

            else if (Nkind (gnat_decl) == N_Freeze_Entity)
              process_decls (Actions (gnat_decl), Empty, Empty, 0, 1);
          }
}
\f
/* Emits an access check. GNU_EXPR is the expression that needs to be
   checked against the NULL pointer. */

static tree
emit_access_check (gnu_expr)
     tree gnu_expr;
{
  tree gnu_type = TREE_TYPE (gnu_expr);

  /* This only makes sense if GNU_TYPE is a pointer of some sort.  */
  if (! POINTER_TYPE_P (gnu_type) && ! TYPE_FAT_POINTER_P (gnu_type))
    gigi_abort (322);

  /* Checked expressions must be evaluated only once. */
  gnu_expr = make_save_expr (gnu_expr);

  return emit_check (build_binary_op (EQ_EXPR, integer_type_node,
                                      gnu_expr,
                                      convert (TREE_TYPE (gnu_expr),
                                               integer_zero_node)),
                     gnu_expr);
}

/* Emits a discriminant check. GNU_EXPR is the expression to be checked and
   GNAT_NODE a N_Selected_Component node. */

static tree
emit_discriminant_check (gnu_expr, gnat_node)
     tree gnu_expr;
     Node_Id gnat_node;
{
  Entity_Id orig_comp
    = Original_Record_Component (Entity (Selector_Name (gnat_node)));
  Entity_Id gnat_discr_fct = Discriminant_Checking_Func (orig_comp);
  tree gnu_discr_fct;
  Entity_Id gnat_discr;
  tree gnu_actual_list = NULL_TREE;
  tree gnu_cond;
  Entity_Id gnat_pref_type;
  tree gnu_pref_type;

  if (Is_Tagged_Type (Scope (orig_comp)))
    gnat_pref_type = Scope (orig_comp);
  else
    gnat_pref_type = Etype (Prefix (gnat_node));

  if (! Present (gnat_discr_fct))
    return gnu_expr;

  gnu_discr_fct = gnat_to_gnu (gnat_discr_fct);

  /* Checked expressions must be evaluated only once. */
  gnu_expr = make_save_expr (gnu_expr);

  /* Create the list of the actual parameters as GCC expects it.
     This list is the list of the discriminant fields of the
     record expression to be discriminant checked. For documentation
     on what is the GCC format for this list see under the
     N_Function_Call case */

 while (IN (Ekind (gnat_pref_type), Incomplete_Or_Private_Kind)
        || IN (Ekind (gnat_pref_type), Access_Kind))
   {
     if (IN (Ekind (gnat_pref_type), Incomplete_Or_Private_Kind)) 
       gnat_pref_type = Underlying_Type (gnat_pref_type);
     else if (IN (Ekind (gnat_pref_type), Access_Kind))
       gnat_pref_type = Designated_Type (gnat_pref_type);
   }

  gnu_pref_type
    = TREE_TYPE (gnat_to_gnu_entity (gnat_pref_type, NULL_TREE, 0));

  for (gnat_discr = First_Discriminant (gnat_pref_type);
       Present (gnat_discr); gnat_discr = Next_Discriminant (gnat_discr))
    {
      Entity_Id gnat_real_discr
        = ((Present (Corresponding_Discriminant (gnat_discr))
            && Present (Parent_Subtype (gnat_pref_type)))
           ? Corresponding_Discriminant (gnat_discr) : gnat_discr);
      tree gnu_discr = gnat_to_gnu_entity (gnat_real_discr, NULL_TREE, 0);

      gnu_actual_list
        = chainon (gnu_actual_list,
                   build_tree_list (NULL_TREE,
                                    build_component_ref 
                                    (convert (gnu_pref_type, gnu_expr),
                                     NULL_TREE, gnu_discr)));
    }

  gnu_cond = build (CALL_EXPR,
                    TREE_TYPE (TREE_TYPE (gnu_discr_fct)),
                    build_unary_op (ADDR_EXPR, NULL_TREE, gnu_discr_fct),
                    gnu_actual_list,
                    NULL_TREE);
  TREE_SIDE_EFFECTS (gnu_cond) = 1;

  return
    build_unary_op
      (INDIRECT_REF, NULL_TREE,
       emit_check (gnu_cond,
                   build_unary_op (ADDR_EXPR,
                                   build_reference_type (TREE_TYPE (gnu_expr)),
                                   gnu_expr)));
}
\f
/* Emit code for a range check. GNU_EXPR is the expression to be checked,
   GNAT_RANGE_TYPE the gnat type or subtype containing the bounds against
   which we have to check. */

static tree
emit_range_check (gnu_expr, gnat_range_type)
     tree gnu_expr;
     Entity_Id gnat_range_type;
{
  tree gnu_range_type = get_unpadded_type (gnat_range_type);
  tree gnu_low  = TYPE_MIN_VALUE (gnu_range_type);
  tree gnu_high = TYPE_MAX_VALUE (gnu_range_type);
  tree gnu_compare_type = get_base_type (TREE_TYPE (gnu_expr));

  /* If GNU_EXPR has an integral type that is narrower than GNU_RANGE_TYPE,
     we can't do anything since we might be truncating the bounds.  No
     check is needed in this case.  */
  if (INTEGRAL_TYPE_P (TREE_TYPE (gnu_expr))
      && (TYPE_PRECISION (gnu_compare_type)
          < TYPE_PRECISION (get_base_type (gnu_range_type))))
    return gnu_expr;

  /* Checked expressions must be evaluated only once. */
  gnu_expr = make_save_expr (gnu_expr);

  /* There's no good type to use here, so we might as well use
     integer_type_node. Note that the form of the check is
        (not (expr >= lo)) or (not (expr >= hi))
      the reason for this slightly convoluted form is that NaN's
      are not considered to be in range in the float case. */
  return emit_check
    (build_binary_op (TRUTH_ORIF_EXPR, integer_type_node,
                      invert_truthvalue
                      (build_binary_op (GE_EXPR, integer_type_node,
                                       convert (gnu_compare_type, gnu_expr),
                                       convert (gnu_compare_type, gnu_low))),
                      invert_truthvalue
                      (build_binary_op (LE_EXPR, integer_type_node,
                                        convert (gnu_compare_type, gnu_expr),
                                        convert (gnu_compare_type,
                                                 gnu_high)))),
     gnu_expr);
}
\f
/* Emit code for an index check. GNU_ARRAY_OBJECT is the array object
   which we are about to index, GNU_EXPR is the index expression to be
   checked, GNU_LOW and GNU_HIGH are the lower and upper bounds
   against which GNU_EXPR has to be checked. Note that for index
   checking we cannot use the emit_range_check function (although very
   similar code needs to be generated in both cases) since for index
   checking the array type against which we are checking the indeces
   may be unconstrained and consequently we need to retrieve the
   actual index bounds from the array object itself
   (GNU_ARRAY_OBJECT). The place where we need to do that is in
   subprograms having unconstrained array formal parameters */

static tree
emit_index_check (gnu_array_object, gnu_expr, gnu_low, gnu_high)
     tree gnu_array_object;
     tree gnu_expr;
     tree gnu_low;
     tree gnu_high;
{
  tree gnu_expr_check;

  /* Checked expressions must be evaluated only once. */
  gnu_expr = make_save_expr (gnu_expr);

  /* Must do this computation in the base type in case the expression's
     type is an unsigned subtypes.  */
  gnu_expr_check = convert (get_base_type (TREE_TYPE (gnu_expr)), gnu_expr);

  /* If GNU_LOW or GNU_HIGH are a PLACEHOLDER_EXPR, qualify them by
     the object we are handling. */
  if (TREE_CODE (gnu_low) != INTEGER_CST && contains_placeholder_p (gnu_low))
    gnu_low = build (WITH_RECORD_EXPR, TREE_TYPE (gnu_low),
                     gnu_low, gnu_array_object);

  if (TREE_CODE (gnu_high) != INTEGER_CST && contains_placeholder_p (gnu_high))
    gnu_high = build (WITH_RECORD_EXPR, TREE_TYPE (gnu_high),
                      gnu_high, gnu_array_object);

  /* There's no good type to use here, so we might as well use
     integer_type_node.   */
  return emit_check
    (build_binary_op (TRUTH_ORIF_EXPR, integer_type_node,
                      build_binary_op (LT_EXPR, integer_type_node,
                                       gnu_expr_check,
                                       convert (TREE_TYPE (gnu_expr_check),
                                                gnu_low)),
                      build_binary_op (GT_EXPR, integer_type_node,
                                       gnu_expr_check,
                                       convert (TREE_TYPE (gnu_expr_check),
                                                gnu_high))),
     gnu_expr);
}
\f
/* Given GNU_COND which contains the condition corresponding to an access,
   discriminant or range check, of value GNU_EXPR, build a COND_EXPR
   that returns GNU_EXPR if GNU_COND is false and raises a
   CONSTRAINT_ERROR if GNU_COND is true.  */

static tree
emit_check (gnu_cond, gnu_expr)
     tree gnu_cond;
     tree gnu_expr;
{
  tree gnu_call;

  gnu_call = build_call_raise (raise_constraint_error_decl);

  /* Use an outer COMPOUND_EXPR to make sure that GNU_EXPR will
     get evaluated in front of the comparison in case it ends
     up being a SAVE_EXPR.  Put the whole thing inside its own
     SAVE_EXPR do the inner SAVE_EXPR doesn't leak out.  */

  return make_save_expr (build (COMPOUND_EXPR, TREE_TYPE (gnu_expr), gnu_expr,
                                fold (build (COND_EXPR, TREE_TYPE (gnu_expr),
                                             gnu_cond,
                                             build (COMPOUND_EXPR,
                                                    TREE_TYPE (gnu_expr),
                                                    gnu_call, gnu_expr),
                                             gnu_expr))));
}
\f
/* Return an expression that converts GNU_EXPR to GNAT_TYPE, doing
   overflow checks if OVERFLOW_P is nonzero and range checks if
   RANGE_P is nonzero.  GNAT_TYPE is known to be an integral type.
   If TRUNCATE_P is nonzero, do a float to integer conversion with
   truncation; otherwise round.  */

static tree
convert_with_check (gnat_type, gnu_expr, overflow_p, range_p, truncate_p)
     Entity_Id gnat_type;
     tree gnu_expr;
     int overflow_p;
     int range_p;
     int truncate_p;
{
  tree gnu_type = get_unpadded_type (gnat_type);
  tree gnu_in_type = TREE_TYPE (gnu_expr);
  tree gnu_in_basetype = get_base_type (gnu_in_type);
  tree gnu_base_type = get_base_type (gnu_type);
  tree gnu_ada_base_type = get_ada_base_type (gnu_type);
  tree gnu_in_lb = TYPE_MIN_VALUE (gnu_in_basetype);
  tree gnu_in_ub = TYPE_MAX_VALUE (gnu_in_basetype);
  tree gnu_out_lb = TYPE_MIN_VALUE (gnu_base_type);
  tree gnu_out_ub = TYPE_MAX_VALUE (gnu_base_type);
  tree gnu_result = gnu_expr;

  /* If we are not doing any checks, the output is an integral type, and
     the input is not a floating type, just do the conversion.  This
     shortcut is required to avoid problems with packed array types
     and simplifies code in all cases anyway.   */
  if (! range_p && ! overflow_p && INTEGRAL_TYPE_P (gnu_base_type)
      && ! FLOAT_TYPE_P (gnu_in_type))
    return convert (gnu_type, gnu_expr);

  /* First convert the expression to its base type.  This
     will never generate code, but makes the tests below much simpler. 
     But don't do this if converting from an integer type to an unconstrained
     array type since then we need to get the bounds from the original
     (unpacked) type.  */
  if (TREE_CODE (gnu_type) != UNCONSTRAINED_ARRAY_TYPE)
    gnu_result = convert (gnu_in_basetype, gnu_result);

  /* If overflow checks are requested,  we need to be sure the result will
     fit in the output base type.  But don't do this if the input
     is integer and the output floating-point.  */
  if (overflow_p
      && ! (FLOAT_TYPE_P (gnu_base_type) && INTEGRAL_TYPE_P (gnu_in_basetype)))
    {
      /* Ensure GNU_EXPR only gets evaluated once.  */
      tree gnu_input = make_save_expr (gnu_result);
      tree gnu_cond = integer_zero_node;

      /* Convert the lower bounds to signed types, so we're sure we're
         comparing them properly.  Likewise, convert the upper bounds
         to unsigned types.  */
      if (INTEGRAL_TYPE_P (gnu_in_basetype) && TREE_UNSIGNED (gnu_in_basetype))
        gnu_in_lb = convert (signed_type (gnu_in_basetype), gnu_in_lb);

      if (INTEGRAL_TYPE_P (gnu_in_basetype)
          && ! TREE_UNSIGNED (gnu_in_basetype))
        gnu_in_ub = convert (unsigned_type (gnu_in_basetype), gnu_in_ub);

      if (INTEGRAL_TYPE_P (gnu_base_type) && TREE_UNSIGNED (gnu_base_type))
        gnu_out_lb = convert (signed_type (gnu_base_type), gnu_out_lb);

      if (INTEGRAL_TYPE_P (gnu_base_type) && ! TREE_UNSIGNED (gnu_base_type))
        gnu_out_ub = convert (unsigned_type (gnu_base_type), gnu_out_ub);

      /* Check each bound separately and only if the result bound
         is tighter than the bound on the input type.  Note that all the
         types are base types, so the bounds must be constant. Also,
         the comparison is done in the base type of the input, which
         always has the proper signedness.  First check for input
         integer (which means output integer), output float (which means
         both float), or mixed, in which case we always compare. 
         Note that we have to do the comparison which would *fail* in the
         case of an error since if it's an FP comparison and one of the
         values is a NaN or Inf, the comparison will fail.  */
      if (INTEGRAL_TYPE_P (gnu_in_basetype)
          ? tree_int_cst_lt (gnu_in_lb, gnu_out_lb)
          : (FLOAT_TYPE_P (gnu_base_type)
             ? REAL_VALUES_LESS (TREE_REAL_CST (gnu_in_lb),
                                 TREE_REAL_CST (gnu_out_lb))
             : 1))
        gnu_cond
          = invert_truthvalue
            (build_binary_op (GE_EXPR, integer_type_node,
                              gnu_input, convert (gnu_in_basetype,
                                                  gnu_out_lb)));

      if (INTEGRAL_TYPE_P (gnu_in_basetype)
          ? tree_int_cst_lt (gnu_out_ub, gnu_in_ub)
          : (FLOAT_TYPE_P (gnu_base_type)
             ? REAL_VALUES_LESS (TREE_REAL_CST (gnu_out_ub),
                                 TREE_REAL_CST (gnu_in_lb))
             : 1))
        gnu_cond
          = build_binary_op (TRUTH_ORIF_EXPR, integer_type_node, gnu_cond,
                             invert_truthvalue
                             (build_binary_op (LE_EXPR, integer_type_node,
                                               gnu_input,
                                               convert (gnu_in_basetype,
                                                        gnu_out_ub))));

      if (! integer_zerop (gnu_cond))
        gnu_result = emit_check (gnu_cond, gnu_input);
    }

  /* Now convert to the result base type.  If this is a non-truncating
     float-to-integer conversion, round.  */
  if (INTEGRAL_TYPE_P (gnu_ada_base_type) && FLOAT_TYPE_P (gnu_in_basetype)
      && ! truncate_p)
    {
      tree gnu_point_5 = build_real (gnu_in_basetype, dconstp5);
      tree gnu_minus_point_5 = build_real (gnu_in_basetype, dconstmp5);
      tree gnu_zero = convert (gnu_in_basetype, integer_zero_node);
      tree gnu_saved_result = save_expr (gnu_result);
      tree gnu_comp = build (GE_EXPR, integer_type_node,
                             gnu_saved_result, gnu_zero);
      tree gnu_adjust = build (COND_EXPR, gnu_in_basetype, gnu_comp,
                               gnu_point_5, gnu_minus_point_5);

      gnu_result
        = build (PLUS_EXPR, gnu_in_basetype, gnu_saved_result, gnu_adjust);
    }

  if (TREE_CODE (gnu_ada_base_type) == INTEGER_TYPE
      && TYPE_HAS_ACTUAL_BOUNDS_P (gnu_ada_base_type)
      && TREE_CODE (gnu_result) == UNCONSTRAINED_ARRAY_REF)
    gnu_result = unchecked_convert (gnu_ada_base_type, gnu_result);
  else
    gnu_result = convert (gnu_ada_base_type, gnu_result);

  /* Finally, do the range check if requested.  Note that if the
     result type is a modular type, the range check is actually
     an overflow check.  */

  if (range_p
      || (TREE_CODE (gnu_base_type) == INTEGER_TYPE
          && TYPE_MODULAR_P (gnu_base_type) && overflow_p))
    gnu_result = emit_range_check (gnu_result, gnat_type);

  return convert (gnu_type, gnu_result);
}
\f
/* Return 1 if GNU_EXPR can be directly addressed.  This is the case unless
   it is an expression involving computation or if it involves a bitfield
   reference.  This returns the same as mark_addressable in most cases.  */

static int
addressable_p (gnu_expr)
     tree gnu_expr;
{
  switch (TREE_CODE (gnu_expr))
    {
    case UNCONSTRAINED_ARRAY_REF:
    case INDIRECT_REF:
    case VAR_DECL:
    case PARM_DECL:
    case FUNCTION_DECL:
    case RESULT_DECL:
    case CONSTRUCTOR:
    case NULL_EXPR:
      return 1;

    case COMPONENT_REF:
      return (! DECL_BIT_FIELD (TREE_OPERAND (gnu_expr, 1))
              && addressable_p (TREE_OPERAND (gnu_expr, 0)));

    case ARRAY_REF:  case ARRAY_RANGE_REF:
    case REALPART_EXPR:  case IMAGPART_EXPR:
    case NOP_EXPR:
      return addressable_p (TREE_OPERAND (gnu_expr, 0));

    case CONVERT_EXPR:
      return (AGGREGATE_TYPE_P (TREE_TYPE (gnu_expr))
              && addressable_p (TREE_OPERAND (gnu_expr, 0)));

    case UNCHECKED_CONVERT_EXPR:
      {
        /* This is addressable if the code in gnat_expand_expr can do
           it by either just taking the operand or by pointer punning.  */
        tree inner = TREE_OPERAND (gnu_expr, 0);
        tree type = TREE_TYPE (gnu_expr);
        tree inner_type = TREE_TYPE (inner);

        return ((TYPE_MODE (type) == TYPE_MODE (inner_type)
                 && (TYPE_ALIGN (type) <= TYPE_ALIGN (inner_type)
                     || TYPE_ALIGN (inner_type) >= BIGGEST_ALIGNMENT))
                || ((TYPE_MODE (type) == BLKmode 
                     || TYPE_MODE (inner_type) == BLKmode)
                    && (TYPE_ALIGN (type) <= TYPE_ALIGN (inner_type)
                        || TYPE_ALIGN (inner_type) >= BIGGEST_ALIGNMENT
                        || TYPE_ALIGN_OK_P (type)
                        || TYPE_ALIGN_OK_P (inner_type))));
      }

    default:
      return 0;
    }
}
\f
/* Do the processing for the declaration of a GNAT_ENTITY, a type.  If
   a separate Freeze node exists, delay the bulk of the processing.  Otherwise
   make a GCC type for GNAT_ENTITY and set up the correspondance.  */

void
process_type (gnat_entity)
     Entity_Id gnat_entity;
{
  tree gnu_old
    = present_gnu_tree (gnat_entity) ? get_gnu_tree (gnat_entity) : 0;
  tree gnu_new;

  /* If we are to delay elaboration of this type, just do any
     elaborations needed for expressions within the declaration and
     make a dummy type entry for this node and its Full_View (if
     any) in case something points to it.  Don't do this if it
     has already been done (the only way that can happen is if
     the private completion is also delayed).  */
  if (Present (Freeze_Node (gnat_entity))
      || (IN (Ekind (gnat_entity), Incomplete_Or_Private_Kind)
          && Present (Full_View (gnat_entity))
          && Freeze_Node (Full_View (gnat_entity))
          && ! present_gnu_tree (Full_View (gnat_entity))))
    {
      elaborate_entity (gnat_entity);

      if (gnu_old == 0)
        {
          tree gnu_decl = create_type_decl (get_entity_name (gnat_entity),
                                            make_dummy_type (gnat_entity),
                                            0, 0, 0);

          save_gnu_tree (gnat_entity, gnu_decl, 0);
          if (IN (Ekind (gnat_entity), Incomplete_Or_Private_Kind)
              && Present (Full_View (gnat_entity)))
            save_gnu_tree (Full_View (gnat_entity), gnu_decl, 0);
        }

      return;
    }

  /* If we saved away a dummy type for this node it means that this
     made the type that corresponds to the full type of an incomplete
     type.  Clear that type for now and then update the type in the
     pointers.  */
  if (gnu_old != 0)
    {
      if (TREE_CODE (gnu_old) != TYPE_DECL
          || ! TYPE_IS_DUMMY_P (TREE_TYPE (gnu_old)))
        {
          /* If this was a withed access type, this is not an error
             and merely indicates we've already elaborated the type
             already. */
          if (Is_Type (gnat_entity) && From_With_Type (gnat_entity))
            return;

          gigi_abort (323);
        }

      save_gnu_tree (gnat_entity, NULL_TREE, 0);
    }

  /* Now fully elaborate the type.  */
  gnu_new = gnat_to_gnu_entity (gnat_entity, NULL_TREE, 1);
  if (TREE_CODE (gnu_new) != TYPE_DECL)
    gigi_abort (324);

  /* If we have an old type and we've made pointers to this type,
     update those pointers.  */
  if (gnu_old != 0)
    update_pointer_to (TYPE_MAIN_VARIANT (TREE_TYPE (gnu_old)),
                       TREE_TYPE (gnu_new));

  /* If this is a record type corresponding to a task or protected type 
     that is a completion of an incomplete type, perform a similar update
     on the type.  */
  /* ??? Including protected types here is a guess. */

  if (IN (Ekind (gnat_entity), Record_Kind)
      && Is_Concurrent_Record_Type (gnat_entity)
      && present_gnu_tree (Corresponding_Concurrent_Type (gnat_entity)))
    {
      tree gnu_task_old
        = get_gnu_tree (Corresponding_Concurrent_Type (gnat_entity));

      save_gnu_tree (Corresponding_Concurrent_Type (gnat_entity),
                     NULL_TREE, 0);
      save_gnu_tree (Corresponding_Concurrent_Type (gnat_entity),
                     gnu_new, 0);

      update_pointer_to (TYPE_MAIN_VARIANT (TREE_TYPE (gnu_task_old)),
                         TREE_TYPE (gnu_new));
    }
}
\f
/* GNAT_ASSOC is the front of the Component_Associations of an N_Aggregate.
   GNU_TYPE is the GCC type of the corresponding record. 

   Return a CONSTRUCTOR to build the record.  */

static tree
assoc_to_constructor (gnat_assoc, gnu_type)
     Node_Id gnat_assoc;
     tree gnu_type;
{
  tree gnu_field, gnu_list, gnu_result;

  /* We test for GNU_FIELD being empty in the case where a variant
     was the last thing since we don't take things off GNAT_ASSOC in
     that case.  We check GNAT_ASSOC in case we have a variant, but it
     has no fields.  */

  for (gnu_list = NULL_TREE; Present (gnat_assoc);
       gnat_assoc = Next (gnat_assoc))
    {
      Node_Id gnat_field = First (Choices (gnat_assoc));
      tree gnu_field = gnat_to_gnu_entity (Entity (gnat_field), NULL_TREE, 0);
      tree gnu_expr = gnat_to_gnu (Expression (gnat_assoc));

      /* The expander is supposed to put a single component selector name
         in every record component association */
      if (Next (gnat_field))
        gigi_abort (328);

      /* Before assigning a value in an aggregate make sure range checks
         are done if required.  Then convert to the type of the field.  */
      if (Do_Range_Check (Expression (gnat_assoc)))
        gnu_expr = emit_range_check (gnu_expr, Etype (gnat_field));

      gnu_expr = convert (TREE_TYPE (gnu_field), gnu_expr);

      /* Add the field and expression to the list.  */
      gnu_list = tree_cons (gnu_field, gnu_expr, gnu_list);
    }

  gnu_result = extract_values (gnu_list, gnu_type);

  /* Verify every enty in GNU_LIST was used.  */
  for (gnu_field = gnu_list; gnu_field; gnu_field = TREE_CHAIN (gnu_field))
    if (! TREE_ADDRESSABLE (gnu_field))
      gigi_abort (311);

  return gnu_result;
}

/* Builds a possibly nested constructor for array aggregates. GNAT_EXPR
   is the first element of an array aggregate. It may itself be an
   aggregate (an array or record aggregate). GNU_ARRAY_TYPE is the gnu type
   corresponding to the array aggregate. GNAT_COMPONENT_TYPE is the type
   of the array component. It is needed for range checking. */

static tree
pos_to_constructor (gnat_expr, gnu_array_type, gnat_component_type)
     Node_Id gnat_expr;
     tree gnu_array_type;
     Entity_Id gnat_component_type;
{
  tree gnu_expr;
  tree gnu_expr_list = NULL_TREE;

  for ( ; Present (gnat_expr); gnat_expr = Next (gnat_expr))
    {
      /* If the expression is itself an array aggregate then first build the
         innermost constructor if it is part of our array (multi-dimensional
         case).  */

      if (Nkind (gnat_expr) == N_Aggregate
          && TREE_CODE (TREE_TYPE (gnu_array_type)) == ARRAY_TYPE
          && TYPE_MULTI_ARRAY_P (TREE_TYPE (gnu_array_type)))
        gnu_expr = pos_to_constructor (First (Expressions (gnat_expr)),
                                       TREE_TYPE (gnu_array_type),
                                       gnat_component_type);
      else
        {
          gnu_expr = gnat_to_gnu (gnat_expr);

          /* before assigning the element to the array make sure it is
             in range */
          if (Do_Range_Check (gnat_expr))
            gnu_expr = emit_range_check (gnu_expr, gnat_component_type);
        }

      gnu_expr_list
        = tree_cons (NULL_TREE, convert (TREE_TYPE (gnu_array_type), gnu_expr),
                     gnu_expr_list);
    }

  return build_constructor (gnu_array_type, nreverse (gnu_expr_list));
}
\f
/* Subroutine of assoc_to_constructor: VALUES is a list of field associations,
   some of which are from RECORD_TYPE.  Return a CONSTRUCTOR consisting
   of the associations that are from RECORD_TYPE.  If we see an internal
   record, make a recursive call to fill it in as well.  */

static tree
extract_values (values, record_type)
     tree values;
     tree record_type;
{
  tree result = NULL_TREE;
  tree field, tem;

  for (field = TYPE_FIELDS (record_type); field; field = TREE_CHAIN (field))
    {
      tree value = 0;

      /* _Parent is an internal field, but may have values in the aggregate,
         so check for values first.  */
      if ((tem = purpose_member (field, values)) != 0)
        {
          value = TREE_VALUE (tem);
          TREE_ADDRESSABLE (tem) = 1;
        }

      else if (DECL_INTERNAL_P (field))
        {
          value = extract_values (values, TREE_TYPE (field));
          if (TREE_CODE (value) == CONSTRUCTOR
              && CONSTRUCTOR_ELTS (value) == 0)
            value = 0;
        }
      else
        /* If we have a record subtype, the names will match, but not the
           actual FIELD_DECLs.  */
        for (tem = values; tem; tem = TREE_CHAIN (tem))
          if (DECL_NAME (TREE_PURPOSE (tem)) == DECL_NAME (field))
            {
              value = convert (TREE_TYPE (field), TREE_VALUE (tem));
              TREE_ADDRESSABLE (tem) = 1;
            }

      if (value == 0)
        continue;

      result = tree_cons (field, value, result);
    }

  return build_constructor (record_type, nreverse (result));
}
\f
/* EXP is to be treated as an array or record.  Handle the cases when it is
   an access object and perform the required dereferences.  */

static tree
maybe_implicit_deref (exp)
     tree exp;
{
  /* If the type is a pointer, dereference it.  */

  if (POINTER_TYPE_P (TREE_TYPE (exp)) || TYPE_FAT_POINTER_P (TREE_TYPE (exp)))
    exp = build_unary_op (INDIRECT_REF, NULL_TREE, exp);

  /* If we got a padded type, remove it too.  */
  if (TREE_CODE (TREE_TYPE (exp)) == RECORD_TYPE
      && TYPE_IS_PADDING_P (TREE_TYPE (exp)))
    exp = convert (TREE_TYPE (TYPE_FIELDS (TREE_TYPE (exp))), exp);

  return exp;
}
\f
/* Surround EXP with a SAVE_EXPR, but handle unconstrained objects specially
   since it doesn't make any sense to put them in a SAVE_EXPR.  */

tree
make_save_expr (exp)
     tree exp;
{
  tree type = TREE_TYPE (exp);

  /* If this is an unchecked conversion, save the input since we may need to
     handle this expression separately if it's the operand of a component
     reference.  */
  if (TREE_CODE (exp) == UNCHECKED_CONVERT_EXPR)
    return build1 (UNCHECKED_CONVERT_EXPR, type,
                   make_save_expr (TREE_OPERAND (exp, 0)));

  /* If this is an aggregate type, we may be doing a dereference of it in
     the LHS side of an assignment.  In that case, we need to evaluate
     it , take its address, make a SAVE_EXPR of that, then do the indirect
     reference.  Note that for an unconstrained array, the effect will be
     to make a SAVE_EXPR of the fat pointer.

     ??? This is an efficiency problem in the case of a type that can be
     placed into memory, but until we can deal with the LHS issue,
     we have to take that hit.  This really should test for BLKmode.  */
  else if (TREE_CODE (type) == UNCONSTRAINED_ARRAY_TYPE
           || (AGGREGATE_TYPE_P (type) && ! TYPE_FAT_POINTER_P (type)))
    return
      build_unary_op (INDIRECT_REF, type,
                      save_expr (build_unary_op (ADDR_EXPR,
                                                 build_reference_type (type),
                                                 exp)));

  /* Otherwise, just do the usual thing.  */
  return save_expr (exp);
}
\f
/* This is equivalent to stabilize_reference in GCC's tree.c, but we know
   how to handle our new nodes and we take an extra argument that says 
   whether to force evaluation of everything.  */

tree
gnat_stabilize_reference (ref, force)
     tree ref;
     int force;
{
  register tree type = TREE_TYPE (ref);
  register enum tree_code code = TREE_CODE (ref);
  register tree result;

  switch (code)
    {
    case VAR_DECL:
    case PARM_DECL:
    case RESULT_DECL:
      /* No action is needed in this case.  */
      return ref;

    case NOP_EXPR:
    case CONVERT_EXPR:
    case FLOAT_EXPR:
    case FIX_TRUNC_EXPR:
    case FIX_FLOOR_EXPR:
    case FIX_ROUND_EXPR:
    case FIX_CEIL_EXPR:
    case UNCHECKED_CONVERT_EXPR:
    case ADDR_EXPR:
      result
        = build1 (code, type,
                  gnat_stabilize_reference (TREE_OPERAND (ref, 0), force));
      break;

    case INDIRECT_REF:
    case UNCONSTRAINED_ARRAY_REF:
      result = build1 (code, type,
                       gnat_stabilize_reference_1 (TREE_OPERAND (ref, 0),
                                                   force));
      break;

    case COMPONENT_REF:
      result = build (COMPONENT_REF, type,
                      gnat_stabilize_reference (TREE_OPERAND (ref, 0),
                                                force),
                      TREE_OPERAND (ref, 1));
      break;

    case BIT_FIELD_REF:
      result = build (BIT_FIELD_REF, type,
                      gnat_stabilize_reference (TREE_OPERAND (ref, 0), force),
                      gnat_stabilize_reference_1 (TREE_OPERAND (ref, 1),
                                                     force),
                      gnat_stabilize_reference_1 (TREE_OPERAND (ref, 2),
                                                  force));
      break;

    case ARRAY_REF:
      result = build (ARRAY_REF, type,
                      gnat_stabilize_reference (TREE_OPERAND (ref, 0), force),
                      gnat_stabilize_reference_1 (TREE_OPERAND (ref, 1),
                                                  force));
      break;

    case ARRAY_RANGE_REF:
      result = build (ARRAY_RANGE_REF, type,
                      gnat_stabilize_reference (TREE_OPERAND (ref, 0), force),
                      gnat_stabilize_reference_1 (TREE_OPERAND (ref, 1),
                                                  force));
      break;

    case COMPOUND_EXPR:
      result = build (COMPOUND_EXPR, type,
                      gnat_stabilize_reference_1 (TREE_OPERAND (ref, 0),
                                                  force),
                      gnat_stabilize_reference (TREE_OPERAND (ref, 1),
                                                force));
      break;

    case RTL_EXPR:
      result = build1 (INDIRECT_REF, type,
                       save_expr (build1 (ADDR_EXPR,
                                          build_reference_type (type), ref)));
      break;

      /* If arg isn't a kind of lvalue we recognize, make no change.
         Caller should recognize the error for an invalid lvalue.  */
    default:
      return ref;

    case ERROR_MARK:
      return error_mark_node;
    }

  TREE_READONLY (result) = TREE_READONLY (ref);
  return result;
}

/* Similar to stabilize_reference_1 in tree.c, but supports an extra
   arg to force a SAVE_EXPR for everything.  */

static tree
gnat_stabilize_reference_1 (e, force)
     tree e;
     int force;
{
  register enum tree_code code = TREE_CODE (e);
  register tree type = TREE_TYPE (e);
  register tree result;

  /* We cannot ignore const expressions because it might be a reference
     to a const array but whose index contains side-effects.  But we can
     ignore things that are actual constant or that already have been
     handled by this function.  */

  if (TREE_CONSTANT (e) || code == SAVE_EXPR)
    return e;

  switch (TREE_CODE_CLASS (code))
    {
    case 'x':
    case 't':
    case 'd':
    case 'b':
    case '<':
    case 's':
    case 'e':
    case 'r':
      if (TREE_SIDE_EFFECTS (e) || force)
        return save_expr (e);
      return e;

    case 'c':
      /* Constants need no processing.  In fact, we should never reach
         here.  */
      return e;

    case '2':
      /* Division is slow and tends to be compiled with jumps,
         especially the division by powers of 2 that is often
         found inside of an array reference.  So do it just once.  */
      if (code == TRUNC_DIV_EXPR || code == TRUNC_MOD_EXPR
          || code == FLOOR_DIV_EXPR || code == FLOOR_MOD_EXPR
          || code == CEIL_DIV_EXPR || code == CEIL_MOD_EXPR
          || code == ROUND_DIV_EXPR || code == ROUND_MOD_EXPR)
        return save_expr (e);
      /* Recursively stabilize each operand.  */
      result = build (code, type,
                      gnat_stabilize_reference_1 (TREE_OPERAND (e, 0), force),
                      gnat_stabilize_reference_1 (TREE_OPERAND (e, 1), force));
      break;

    case '1':
      /* Recursively stabilize each operand.  */
      result = build1 (code, type,
                       gnat_stabilize_reference_1 (TREE_OPERAND (e, 0),
                                                   force));
      break;

    default:
      abort ();
    }

  TREE_READONLY (result) = TREE_READONLY (e);
  return result;
}
\f
/* GNAT_UNIT is the Defining_Identifier for some package or subprogram,
   either a spec or a body, BODY_P says which.  If needed, make a function
   to be the elaboration routine for that object and perform the elaborations
   in GNU_ELAB_LIST.

   Return 1 if we didn't need an elaboration function, zero otherwise.  */

static int
build_unit_elab (gnat_unit, body_p, gnu_elab_list)
     Entity_Id gnat_unit;
     int body_p;
     tree gnu_elab_list;
{
  tree gnu_decl;
  rtx insn;
  int result = 1;

  /* If we have nothing to do, return.  */
  if (gnu_elab_list == 0)
    return 1;

  /* Set our file and line number to that of the object and set up the
     elaboration routine.  */
  gnu_decl = create_subprog_decl (create_concat_name (gnat_unit,
                                                      body_p ?
                                                      "elabb" : "elabs"),
                                  NULL_TREE, void_ftype, NULL_TREE, 0, 1, 0, 
                                  0);
  DECL_ELABORATION_PROC_P (gnu_decl) = 1;

  begin_subprog_body (gnu_decl);
  set_lineno (gnat_unit, 1);
  pushlevel (0);
  gnu_block_stack = tree_cons (NULL_TREE, NULL_TREE, gnu_block_stack);
  expand_start_bindings (0);

  /* Emit the assignments for the elaborations we have to do.  If there
     is no destination, this is just a call to execute some statement
     that was placed within the declarative region.   But first save a
     pointer so we can see if any insns were generated.  */

  insn = get_last_insn ();

  for (; gnu_elab_list; gnu_elab_list = TREE_CHAIN (gnu_elab_list))
    if (TREE_PURPOSE (gnu_elab_list) == NULL_TREE)
      {
        if (TREE_VALUE (gnu_elab_list) != 0)
          expand_expr_stmt (TREE_VALUE (gnu_elab_list));
      }
    else
      {
        tree lhs = TREE_PURPOSE (gnu_elab_list);

        input_filename = DECL_SOURCE_FILE (lhs);
        lineno = DECL_SOURCE_LINE (lhs);

        /* If LHS has a padded type, convert it to the unpadded type
           so the assignment is done properly.  */
        if (TREE_CODE (TREE_TYPE (lhs)) == RECORD_TYPE
            && TYPE_IS_PADDING_P (TREE_TYPE (lhs)))
          lhs = convert (TREE_TYPE (TYPE_FIELDS (TREE_TYPE (lhs))), lhs);

        emit_line_note (input_filename, lineno);
        expand_expr_stmt (build_binary_op (MODIFY_EXPR, NULL_TREE,
                                           TREE_PURPOSE (gnu_elab_list),
                                           TREE_VALUE (gnu_elab_list)));
      }

  /* See if any non-NOTE insns were generated.  */
  for (insn = NEXT_INSN (insn); insn; insn = NEXT_INSN (insn))
    if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
      {
        result = 0;
        break;
      }

  expand_end_bindings (getdecls (), kept_level_p (), 0);
  poplevel (kept_level_p (), 1, 0);
  gnu_block_stack = TREE_CHAIN (gnu_block_stack);
  end_subprog_body ();

  /* If there were no insns, we don't need an elab routine.  It would
     be nice to not output this one, but there's no good way to do that.  */
  return result;
}
\f
extern char *__gnat_to_canonical_file_spec PARAMS ((char *));

/* Determine the input_filename and the lineno from the source location
   (Sloc) of GNAT_NODE node.  Set the global variable input_filename and
   lineno.  If WRITE_NOTE_P is true, emit a line number note.  */

void
set_lineno (gnat_node, write_note_p)
     Node_Id gnat_node;
     int write_note_p;
{
  Source_Ptr source_location = Sloc (gnat_node);

  /* If node not from source code, ignore.  */
  if (source_location < 0)
    return;

  /* Use the identifier table to make a hashed, permanent copy of the filename,
     since the name table gets reallocated after Gigi returns but before all
     the debugging information is output. The call to
     __gnat_to_canonical_file_spec translates filenames from pragmas
     Source_Reference that contain host style syntax not understood by gdb. */
  input_filename
    = IDENTIFIER_POINTER
      (get_identifier
       (__gnat_to_canonical_file_spec
        (Get_Name_String
         (Debug_Source_Name (Get_Source_File_Index (source_location))))));

  /* ref_filename is the reference file name as given by sinput (i.e no
     directory) */
  ref_filename
    = IDENTIFIER_POINTER
      (get_identifier
       (Get_Name_String
        (Reference_Name (Get_Source_File_Index (source_location)))));;
  lineno = Get_Logical_Line_Number (source_location);

  if (write_note_p)
    emit_line_note (input_filename, lineno);
}
\f
/* Post an error message.  MSG is the error message, properly annotated.
   NODE is the node at which to post the error and the node to use for the
   "&" substitution.  */

void
post_error (msg, node)
     const char *msg;
     Node_Id node;
{
  String_Template temp;
  Fat_Pointer fp;

  temp.Low_Bound = 1, temp.High_Bound = strlen (msg);
  fp.Array = msg, fp.Bounds = &temp;
  if (Present (node))
    Error_Msg_N (fp, node);
}

/* Similar, but NODE is the node at which to post the error and ENT
   is the node to use for the "&" substitution.  */

void
post_error_ne (msg, node, ent)
     const char *msg;
     Node_Id node;
     Entity_Id ent;
{
  String_Template temp;
  Fat_Pointer fp;

  temp.Low_Bound = 1, temp.High_Bound = strlen (msg);
  fp.Array = msg, fp.Bounds = &temp;
  if (Present (node))
    Error_Msg_NE (fp, node, ent);
}

/* Similar, but NODE is the node at which to post the error, ENT is the node
   to use for the "&" substitution, and N is the number to use for the ^.  */

void
post_error_ne_num (msg, node, ent, n)
     const char *msg;
     Node_Id node;
     Entity_Id ent;
     int n;
{
  String_Template temp;
  Fat_Pointer fp;

  temp.Low_Bound = 1, temp.High_Bound = strlen (msg);
  fp.Array = msg, fp.Bounds = &temp;
  Error_Msg_Uint_1 = UI_From_Int (n);

  if (Present (node))
    Error_Msg_NE (fp, node, ent);
}
\f
/* Similar to post_error_ne_num, but T is a GCC tree representing the
   number to write.  If the tree represents a constant that fits within
   a host integer, the text inside curly brackets in MSG will be output
   (presumably including a '^').  Otherwise that text will not be output
   and the text inside square brackets will be output instead.  */

void
post_error_ne_tree (msg, node, ent, t)
     const char *msg;
     Node_Id node;
     Entity_Id ent;
     tree t;
{
  char *newmsg = alloca (strlen (msg) + 1);
  String_Template temp = {1, 0};
  Fat_Pointer fp;
  char start_yes, end_yes, start_no, end_no;
  const char *p;
  char *q;

  fp.Array = newmsg, fp.Bounds = &temp;

  if (host_integerp (t, 1)
#if HOST_BITS_PER_WIDE_INT > HOST_BITS_PER_INT
      && compare_tree_int (t, 1 << (HOST_BITS_PER_INT - 2)) < 0
#endif
      )
    {
      Error_Msg_Uint_1 = UI_From_Int (tree_low_cst (t, 1));
      start_yes = '{', end_yes = '}', start_no = '[', end_no = ']';
    }
  else
    start_yes = '[', end_yes = ']', start_no = '{', end_no = '}';

  for (p = msg, q = newmsg; *p != 0; p++)
    {
      if (*p == start_yes)
        for (p++; *p != end_yes; p++)
          *q++ = *p;
      else if (*p == start_no)
        for (p++; *p != end_no; p++)
          ;
      else
        *q++ = *p;
    }

  *q = 0;

  temp.High_Bound = strlen (newmsg);
  if (Present (node))
    Error_Msg_NE (fp, node, ent);
}

/* Similar to post_error_ne_tree, except that NUM is a second
   integer to write in the message.  */

void
post_error_ne_tree_2 (msg, node, ent, t, num)
     const char *msg;
     Node_Id node;
     Entity_Id ent;
     tree t;
     int num;
{
  Error_Msg_Uint_2 = UI_From_Int (num);
  post_error_ne_tree (msg, node, ent, t);
}

/* Set the node for a second '&' in the error message.  */

void
set_second_error_entity (e)
     Entity_Id e;
{
  Error_Msg_Node_2 = e;
}
\f
/* Signal abort, with "Gigi abort" as the error label, and error_gnat_node
   as the relevant node that provides the location info for the error */

void
gigi_abort (code)
     int code;
{
  String_Template temp = {1, 10};
  Fat_Pointer fp;

  fp.Array = "Gigi abort", fp.Bounds = &temp;

  Current_Error_Node = error_gnat_node;
  Compiler_Abort (fp, code);
}
\f
/* Initialize the table that maps GNAT codes to GCC codes for simple
   binary and unary operations.  */

void
init_code_table ()
{
  gnu_codes[N_And_Then] = TRUTH_ANDIF_EXPR;
  gnu_codes[N_Or_Else] = TRUTH_ORIF_EXPR;

  gnu_codes[N_Op_And] = TRUTH_AND_EXPR;
  gnu_codes[N_Op_Or] = TRUTH_OR_EXPR;
  gnu_codes[N_Op_Xor] = TRUTH_XOR_EXPR;
  gnu_codes[N_Op_Eq] = EQ_EXPR;
  gnu_codes[N_Op_Ne] = NE_EXPR;
  gnu_codes[N_Op_Lt] = LT_EXPR;
  gnu_codes[N_Op_Le] = LE_EXPR;
  gnu_codes[N_Op_Gt] = GT_EXPR;
  gnu_codes[N_Op_Ge] = GE_EXPR;
  gnu_codes[N_Op_Add] = PLUS_EXPR;
  gnu_codes[N_Op_Subtract] = MINUS_EXPR;
  gnu_codes[N_Op_Multiply] = MULT_EXPR;
  gnu_codes[N_Op_Mod] = FLOOR_MOD_EXPR;
  gnu_codes[N_Op_Rem] = TRUNC_MOD_EXPR;
  gnu_codes[N_Op_Minus] = NEGATE_EXPR;
  gnu_codes[N_Op_Abs] = ABS_EXPR;
  gnu_codes[N_Op_Not] = TRUTH_NOT_EXPR;
  gnu_codes[N_Op_Rotate_Left] = LROTATE_EXPR;
  gnu_codes[N_Op_Rotate_Right] = RROTATE_EXPR;
  gnu_codes[N_Op_Shift_Left] = LSHIFT_EXPR;
  gnu_codes[N_Op_Shift_Right] = RSHIFT_EXPR;
  gnu_codes[N_Op_Shift_Right_Arithmetic] = RSHIFT_EXPR;
}