path: root/TAO/TAO_IDL/ast/ast_union.cpp

// $Id$

/*

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*/

// AST_Union nodes represent IDL union declarations.
// AST_Union is a subclass of AST_ConcreteType and of UTL_Scope (the
// union branches are managed in a scope).
// AST_Union nodes have a discriminator type (a subclass of AST_ConcreteType),
// a name (an UTL_ScopedName) and a field denoting the discriminator type if
// it is a primitive type (the value of this field is from the union
// AST_Expression::ExprType and serves as a cache). This field is used
// to compute coercions for labels based on the expected discriminator type.

#include "ast_union.h"
#include "ast_union_branch.h"
#include "ast_union_label.h"
#include "ast_field.h"
#include "ast_predefined_type.h"
#include "ast_enum.h"
#include "ast_enum_val.h"
#include "ast_visitor.h"
#include "utl_err.h"
#include "utl_identifier.h"
#include "utl_indenter.h"
#include "global_extern.h"

// FUZZ: disable check_for_streams_include
#include "ace/streams.h"

ACE_RCSID (ast,
           ast_union,
           "$Id$")

AST_Union::AST_Union (void)
  : COMMON_Base (),
    AST_Decl (),
    AST_Type (),
    AST_ConcreteType (),
    UTL_Scope (),
    AST_Structure (),
    default_index_ (-2)
{
}

AST_Union::AST_Union (AST_ConcreteType *dt,
                      UTL_ScopedName *n,
                      bool local,
                      bool abstract)
  : COMMON_Base (local,
                 abstract),
    AST_Decl (AST_Decl::NT_union,
              n),
    AST_Type (AST_Decl::NT_union,
              n),
    AST_ConcreteType (AST_Decl::NT_union,
                      n),
    UTL_Scope (AST_Decl::NT_union),
    AST_Structure (n,
                   local,
                   abstract),
    default_index_ (-2)
{
  this->default_value_.computed_ = -2;

  AST_PredefinedType *pdt = 0;

  if (dt == 0)
    {
      this->pd_disc_type = 0;
      this->pd_udisc_type = AST_Expression::EV_none;
      return;
    }

  // If the discriminator type is a predefined type
  // then install the equivalent coercion target type in
  // the pd_udisc_type field.
  if (dt->node_type () == AST_Decl::NT_pre_defined)
    {
      pdt = AST_PredefinedType::narrow_from_decl (dt);

      if (pdt == 0)
        {
          this->pd_disc_type = 0;
          this->pd_udisc_type = AST_Expression::EV_none;
          return;
        }

      pd_disc_type = dt;

      switch (pdt->pt ())
        {
        case AST_PredefinedType::PT_long:
          this->pd_udisc_type = AST_Expression::EV_long;
          break;
        case AST_PredefinedType::PT_ulong:
          this->pd_udisc_type = AST_Expression::EV_ulong;
          break;
        case AST_PredefinedType::PT_short:
          this->pd_udisc_type = AST_Expression::EV_short;
          break;
        case AST_PredefinedType::PT_ushort:
          this->pd_udisc_type = AST_Expression::EV_ushort;
          break;
        case AST_PredefinedType::PT_char:
          this->pd_udisc_type = AST_Expression::EV_char;
          break;
        case AST_PredefinedType::PT_wchar:
          this->pd_udisc_type = AST_Expression::EV_wchar;
          break;
        case AST_PredefinedType::PT_octet:
          this->pd_udisc_type = AST_Expression::EV_octet;
          break;
        case AST_PredefinedType::PT_boolean:
          this->pd_udisc_type = AST_Expression::EV_bool;
          break;
        default:
          this->pd_udisc_type = AST_Expression::EV_none;
          this->pd_disc_type = 0;
          break;
        }
    }
  else if (dt->node_type () == AST_Decl::NT_enum)
    {
      this->pd_udisc_type = AST_Expression::EV_enum;
      this->pd_disc_type = dt;
    }
  else
    {
      this->pd_udisc_type = AST_Expression::EV_none;
      this->pd_disc_type = 0;
    }

  if (this->pd_disc_type == 0)
    {
      idl_global->err ()->error2 (UTL_Error::EIDL_DISC_TYPE,
                                  this,
                                  dt);
    }
}

AST_Union::~AST_Union (void)
{
}

// Public operations.

void
AST_Union::redefine (AST_Structure *from)
{
  AST_Union *u = AST_Union::narrow_from_decl (from);

  if (u == 0)
    {
      idl_global->err ()->redef_error (from->local_name ()->get_string (),
                                       this->local_name ()->get_string ());
      return;
    }

  // Copy over all the base class members.
  this->AST_Structure::redefine (from);

  this->pd_disc_type = u->pd_disc_type;
  this->pd_udisc_type = u->pd_udisc_type;
  this->default_index_ = u->default_index_;
  this->default_value_ = u->default_value_;
}

// Return the default_index.
int
AST_Union::default_index (void)
{
  if (this->default_index_ == -2)
    {
      this->compute_default_index ();
    }

  return this->default_index_;
}

// Are we or the parameter node involved in any recursion?
bool
AST_Union::in_recursion (ACE_Unbounded_Queue<AST_Type *> &list)
{
  // Proceed if the number of members in our scope is greater than 0.
  if (this->nmembers () > 0)
    {
      ACE_Unbounded_Queue<AST_Type *> scope_list = list;
      scope_list.enqueue_tail (this);

      // Initialize an iterator to iterate thru our scope.
      // Continue until each element is visited.
      for (UTL_ScopeActiveIterator si (this, UTL_Scope::IK_decls);
           !si.is_done ();
           si.next ())
        {
          AST_UnionBranch *field =
            AST_UnionBranch::narrow_from_decl (si.item ());

          if (field == 0)
            // This will be an enum value or other legitimate non-field
            // member - in any case, no recursion.
            {
              continue;
            }

          AST_Type *type = field->field_type ();

          if (type->node_type () == AST_Decl::NT_typedef)
            {
              AST_Typedef *td = AST_Typedef::narrow_from_decl (type);
              type = td->primitive_base_type ();
            }

          if (type == 0)
            {
              ACE_ERROR_RETURN ((LM_ERROR,
                                 ACE_TEXT ("(%N:%l) AST_Union::")
                                 ACE_TEXT ("in_recursion - ")
                                 ACE_TEXT ("bad field type\n")),
                                0);
            }

          if (type->in_recursion (scope_list))
            {
              this->in_recursion_ = 1;
              idl_global->recursive_type_seen_ = true;
              return this->in_recursion_;
            }
        }
    }

  // Not in recursion.
  this->in_recursion_ = 0;
  return this->in_recursion_;
}

// Look up the default branch in union.
AST_UnionBranch *
AST_Union::lookup_default (void)
{
  AST_UnionBranch *b = 0;
  AST_Decl *d = 0;

  for (UTL_ScopeActiveIterator i (this, UTL_Scope::IK_both);
       !i.is_done();
       i.next ())
    {
      d = i.item ();

      if (d->node_type () == AST_Decl::NT_union_branch)
        {
          b = AST_UnionBranch::narrow_from_decl (d);

          if (b == 0)
            {
              continue;
            }

          if (b->label () != 0
              && b->label ()->label_kind () == AST_UnionLabel::UL_default)
            {
              idl_global->err ()->error2 (UTL_Error::EIDL_MULTIPLE_BRANCH,
                                          this,
                                          b);
              return b;
            }
        }
    }

  return 0;
}

// Look up a branch by label.
AST_UnionBranch *
AST_Union::lookup_label (AST_UnionBranch *b)
{
  AST_UnionLabel *label = b->label ();
  AST_Expression *lv = label->label_val ();

  if (label->label_val () == 0)
    {
      return b;
    }

  AST_Decl *d = 0;
  AST_UnionBranch       *fb = 0;

  lv->set_ev (lv->coerce (this->pd_udisc_type));

  if (lv->ev () == 0)
    {
      idl_global->err ()->eval_error (lv);
      return b;
    }

  for (UTL_ScopeActiveIterator i (this, UTL_Scope::IK_decls);
       !i.is_done();
       i.next ())
    {
      d = i.item ();

      if (d->node_type () == AST_Decl::NT_union_branch)
        {
          fb = AST_UnionBranch::narrow_from_decl (d);

          if (fb == 0)
            {
              continue;
            }

          if (fb->label() != 0
              && fb->label ()->label_kind () == AST_UnionLabel::UL_label
              && fb->label ()->label_val ()->compare (lv))
            {
              idl_global->err ()->error2  (UTL_Error::EIDL_MULTIPLE_BRANCH,
                                           this,
                                           b);
              return b;
            }
        }
    }

  return 0;
}

// Look up a branch in an enum which is the discriminator type for this
// union, based on the label value which must be an enumerator in that
// enum.
AST_UnionBranch *
AST_Union::lookup_enum (AST_UnionBranch *b)
{
  AST_UnionLabel *label = b->label();
  AST_Expression *lv = label->label_val ();
  AST_Enum *e = AST_Enum::narrow_from_decl (this->pd_disc_type);
  AST_Decl *d = 0;
  AST_UnionBranch       *fb = 0;

  if (e == 0)
    {
      return 0;
    }

  if (lv == 0)
    {
      return b;
    }

  // Expecting a symbol label.
  if (lv->ec () != AST_Expression::EC_symbol)
    {
      idl_global->err ()->enum_val_expected (this,
                                             label);
      return b;
    }

  // See if the symbol defines a constant in the discriminator enum.
  UTL_ScopedName *sn = lv->n ();
  d = e->lookup_by_name (sn,
                         true);

  if (d == 0 || d->defined_in () != e)
    {
      idl_global->err ()->enum_val_lookup_failure (this,
                                                   e,
                                                   sn);
      return b;
    }

  // OK, now see if this symbol is already used as the label of
  // some other branch.
  for (UTL_ScopeActiveIterator i (this, UTL_Scope::IK_decls);
       !i.is_done();
       i.next ())
    {
      d = i.item ();

      if (d->node_type () == AST_Decl::NT_union_branch)
        {
          fb = AST_UnionBranch::narrow_from_decl (d);

          if (fb == 0)
            {
              continue;
            }

          if (fb->label() != 0
              && fb->label ()->label_kind () == AST_UnionLabel::UL_label
              && fb->label ()->label_val ()->compare (lv))
            {
              idl_global->err ()->error2 (UTL_Error::EIDL_MULTIPLE_BRANCH,
                                          this,
                                          b);
              return b;
            }
        }
    }

  return 0;
}

// Look up a branch by value. This is the top level branch label resolution
// entry point. It dispatches to the right lookup function depending on the
// union discriminator type.
AST_UnionBranch *
AST_Union::lookup_branch (AST_UnionBranch *branch)
{
  AST_UnionLabel *label = 0;

  if (branch != 0)
    {
      label = branch->label ();
    }

  if (label != 0)
    {
      if (label->label_kind () == AST_UnionLabel::UL_default)
        {
          return this->lookup_default ();
        }

      if (this->pd_udisc_type == AST_Expression::EV_enum)
        {
          // CONVENTION: indicates enum discriminant.
          return this->lookup_enum (branch);
        }

      return this->lookup_label (branch);
    }

  return 0;
}

// Return the default value.
int
AST_Union::default_value (AST_Union::DefaultValue &dv)
{
  if (this->default_value_.computed_ == -2)
    {
      // We need to compute it.
      if (this->compute_default_value () == -1)
        {
          ACE_ERROR_RETURN ((LM_ERROR,
                             ACE_TEXT ("(%N:%l) AST_Union::")
                             ACE_TEXT ("default_value - ")
                             ACE_TEXT ("Error computing ")
                             ACE_TEXT ("default value\n")),
                            -1);
        }
    }

  dv = this->default_value_;
  return 0;
}

// Determine the default value (if any).
int
AST_Union::compute_default_value (void)
{
  // Check if we really need a default value. This will be true if there is an
  // explicit default case OR if an implicit default exists because not all
  // values of the discriminant type are covered by the cases.

  // Compute the total true "case" labels i.e., exclude the "default" case.
  int total_case_members = 0;

  // Instantiate a scope iterator.
  for (UTL_ScopeActiveIterator si (this, UTL_Scope::IK_decls);
       !si.is_done ();
       si.next ())
    {
      // Get the next AST decl node.
      AST_UnionBranch *ub =
        AST_UnionBranch::narrow_from_decl (si.item ());

      if (ub != 0)
        {
          // If the label is a case label, increment by 1.
          for (unsigned long i = 0; i < ub->label_list_length (); ++i)
            {
              if (ub->label (i)->label_kind () == AST_UnionLabel::UL_label)
                {
                  ++total_case_members;
                }
            }
        }
    }

  // Check if the total_case_members cover the entire
  // range of values that are permitted by the discriminant type. If they do,
  // then a default value is not necessary. However, if such an explicit
  // default case is provided, it must be flagged off as an error. Our
  // front-end is not able to handle such a case since it is a semantic error
  // and not a syntax error. Such an error is caught here.

  switch (this->udisc_type ())
    {
    case AST_Expression::EV_short:
    case AST_Expression::EV_ushort:
      if (total_case_members == ACE_UINT16_MAX + 1)
        {
          this->default_value_.computed_ = 0;
        }

      break;
    case AST_Expression::EV_long:
    case AST_Expression::EV_ulong:
      if ((unsigned int) total_case_members > ACE_UINT32_MAX)
        {
          this->default_value_.computed_ = 0;
        }

      break;
    case AST_Expression::EV_longlong:
    case AST_Expression::EV_ulonglong:
      // Error for now.
      this->default_value_.computed_ = -1;
      ACE_ERROR_RETURN ((
          LM_ERROR,
          ACE_TEXT ("(%N:%l) AST_Union::compute_default_value ")
          ACE_TEXT ("- unimplemented discriminant type ")
          ACE_TEXT ("(longlong or ulonglong)\n")
        ),
        -1
      );
      ACE_NOTREACHED (break;)
    case AST_Expression::EV_char:
      if (total_case_members == ACE_OCTET_MAX + 1)
        {
          this->default_value_.computed_ = 0;
        }

      break;
    case AST_Expression::EV_wchar:
      if (total_case_members == ACE_WCHAR_MAX + 1)
        {
          this->default_value_.computed_ = 0;
        }

      break;
    case AST_Expression::EV_bool:
      if (total_case_members == 2)
        {
          this->default_value_.computed_ = 0;
        }

      break;
    case AST_Expression::EV_enum:
      // Has to be enum.
      {
        AST_Decl *d = AST_Decl::narrow_from_decl (this->disc_type ());

        if (d->node_type () == AST_Decl::NT_typedef)
          {
            AST_Typedef *bt = AST_Typedef::narrow_from_decl (d);
            d = bt->primitive_base_type ();
          }

        AST_Enum *en = AST_Enum::narrow_from_decl (d);

        if (en != 0)
          {
            if (total_case_members == en->member_count ())
              {
                this->default_value_.computed_ = 0;
              }
          }
        else
          {
            // Error.
            this->default_value_.computed_ = -1;
            ACE_ERROR_RETURN ((LM_ERROR,
                               ACE_TEXT ("(%N:%l) AST_Union::")
                               ACE_TEXT ("compute_default_value ")
                               ACE_TEXT ("- disc type not an ENUM\n")),
                              -1);
          }
      }
      break;
    default:
      // Error.
      this->default_value_.computed_ = -1;
      ACE_ERROR_RETURN ((LM_ERROR,
                         ACE_TEXT ("(%N:%l) AST_Union::compute_default_value")
                         ACE_TEXT (" - Bad discriminant type\n")),
                        -1);
      ACE_NOTREACHED (break;)
    } // End of switch

  // If we have determined that we don't have a default case and even then a
  // default case was provided, flag this off as error.
  if ((this->default_value_.computed_ == 0)
      && (this->default_index () != -1))
    {
      // Error.
      this->default_value_.computed_ = -1;
      ACE_ERROR_RETURN ((LM_ERROR,
                         ACE_TEXT ("(%N:%l) AST_Union::compute_default_value")
                         ACE_TEXT (" - default clause is invalid here\n")),
                        -1);
    }

  // Proceed only if necessary.
  switch (this->default_value_.computed_)
    {
    case -1:
      // Error. We should never be here because errors
      // have already been caught
      // above.
      return -1;
    case 0:
      // Nothing more to do.
      return 0;
    default:
      // Proceed further down.
      break;
    }

  // Initialization of the default value data member.
  switch (this->udisc_type ())
    {
    case AST_Expression::EV_short:
      this->default_value_.u.short_val = ACE_INT16_MIN;
      break;
    case AST_Expression::EV_ushort:
      this->default_value_.u.ushort_val = 0;
      break;
    case AST_Expression::EV_long:
      // The +1 is to avert a warning on many compilers.
      this->default_value_.u.long_val = ACE_INT32_MIN + 1;
      break;
    case AST_Expression::EV_ulong:
      this->default_value_.u.ulong_val = 0;
      break;
    case AST_Expression::EV_char:
      this->default_value_.u.char_val = 0;
      break;
    case AST_Expression::EV_wchar:
      this->default_value_.u.wchar_val = 0;
      break;
    case AST_Expression::EV_bool:
      this->default_value_.u.bool_val = 0;
      break;
    case AST_Expression::EV_enum:
      this->default_value_.u.enum_val = 0;
      break;
    case AST_Expression::EV_longlong:
    case AST_Expression::EV_ulonglong:
      // Unimplemented.
    default:
      // Error caught earlier.
      break;
    }

  // Proceed until we have found the appropriate default value.
  while (this->default_value_.computed_ == -2)
    {
      int break_loop = 0;

      // Instantiate a scope iterator.
      for (UTL_ScopeActiveIterator si (this, UTL_Scope::IK_decls);
           !si.is_done () && break_loop == 0;
           si.next ())
        {
          // Get the next AST decl node
          AST_UnionBranch *ub =
            AST_UnionBranch::narrow_from_decl (si.item ());

          if (ub != 0)
            {
              for (unsigned long i = 0;
                   i < ub->label_list_length () && !break_loop;
                   ++i)
                {
                  if (ub->label (i)->label_kind () == AST_UnionLabel::UL_label)
                    {
                      // Not a default.
                      AST_Expression *expr = ub->label (i)->label_val ();

                      if (expr == 0)
                        {
                          // Error.
                          this->default_value_.computed_ = -1;
                          ACE_ERROR_RETURN ((
                              LM_ERROR,
                              ACE_TEXT ("(%N:%l) AST_Union::")
                              ACE_TEXT ("compute_default_value - ")
                              ACE_TEXT ("Bad case label value\n")
                            ),
                            -1
                          );
                        }

                      switch (expr->ev ()->et)
                        {
                          // Check if they match in which case this
                          // cannot be the implicit default value. So
                          // start with a new value and try the whole loop
                          // again because our case labels may not be sorted.
                        case AST_Expression::EV_short:
                          if (this->default_value_.u.short_val
                                == expr->ev ()->u.sval)
                            {
                              this->default_value_.u.short_val++;
                              break_loop = 1;
                            }

                          break;
                        case AST_Expression::EV_ushort:
                          if (this->default_value_.u.ushort_val
                                == expr->ev ()->u.usval)
                            {
                              this->default_value_.u.ushort_val++;
                              break_loop = 1;
                            }

                          break;
                        case AST_Expression::EV_long:
                          if (this->default_value_.u.long_val
                                == expr->ev ()->u.lval)
                            {
                              this->default_value_.u.long_val++;
                              break_loop = 1;
                            }

                          break;
                        case AST_Expression::EV_ulong:
                          if (this->default_value_.u.ulong_val
                                == expr->ev ()->u.ulval)
                            {
                              this->default_value_.u.ulong_val++;
                              break_loop = 1;
                            }

                          break;
                        case AST_Expression::EV_char:
                          if (this->default_value_.u.char_val
                                == expr->ev ()->u.cval)
                            {
                              this->default_value_.u.char_val++;
                              break_loop = 1;
                            }

                          break;
                        case AST_Expression::EV_wchar:
                          if (this->default_value_.u.wchar_val
                                == expr->ev ()->u.wcval)
                            {
                              this->default_value_.u.wchar_val++;
                              break_loop = 1;
                            }

                          break;
                        case AST_Expression::EV_bool:
                          if (this->default_value_.u.bool_val
                                == expr->ev ()->u.bval)
                            {
                              this->default_value_.u.bool_val ^= true;
                              break_loop = 1;
                            }

                          break;
                        case AST_Expression::EV_enum:
                          // this is the case of enums. We maintain
                          // evaluated values which always start with 0
                          if (this->default_value_.u.enum_val
                                == expr->ev ()->u.eval)
                            {
                              this->default_value_.u.enum_val++;
                              break_loop = 1;
                            }

                          break;
                        case AST_Expression::EV_longlong:
                        case AST_Expression::EV_ulonglong:
                          // Unimplemented. right now - flag as error.
                        default:
                          // Error.
                          break;
                        } // End of switch.
                    } // if label_Kind == label
                } // End of for loop going thru all labels.
            } // If valid union branch.
        } // End of while scope iterator loop.

      // We have not aborted the inner loops which means we have found the
      // default value.
      if (break_loop == 0)
        {
          this->default_value_.computed_ = 1;
        }

    } // End of outer while (default_value.computed == -2).

  return 0;
}

// Private  operations.

// Compute the default index.
int
AST_Union::compute_default_index (void)
{
  AST_Decl *d = 0;
  AST_UnionBranch *ub = 0;
  int i = 0;

  // If default case does not exist, it will have a value of -1 according to
  // the spec.
  this->default_index_ = -1;

  // If there are elements in this scope...
  if (this->nmembers () > 0)
    {
      // Instantiate a scope iterator.
      for (UTL_ScopeActiveIterator si (this, UTL_Scope::IK_decls);
           !si.is_done ();
           si.next ())
        {
          // Get the next AST decl node.
          d = si.item ();

          // If an enum is declared in our scope, its members are
          // added to our scope as well, to detect clashes.
          if (d->node_type () == AST_Decl::NT_enum_val)
            {
              continue;
            }

          if (!d->imported ())
            {
              ub = AST_UnionBranch::narrow_from_decl (d);

              for (unsigned long j = 0; j < ub->label_list_length (); ++j)
                {
                  // Check if we are printing the default case.
                  AST_UnionLabel::UnionLabel ulk = ub->label ()->label_kind ();
                  if (ulk == AST_UnionLabel::UL_default)
                    {
                      // Zero based indexing.
                      this->default_index_ = i;
                    }
                }

              // TAO's Typecode class keeps only a member count (not
              // a label count) so this increment has been moved
              // out of the inner loop.
              ++i;
            }
        }
    }

  return 0;
}

// Redefinition of inherited virtual operations

// Add this AST_UnionBranch node (a node representing one branch in a
// union declaration) to this scope
AST_UnionBranch *
AST_Union::fe_add_union_branch (AST_UnionBranch *t)
{
  AST_Decl *d = 0;

  // If this is a malformed branch, don't do anything with it.
  if (t == 0 || t->label() == 0)
    {
      return 0;
    }

  // If branch with that label already exists, complain.
  if (lookup_branch (t) != 0)
    {
      idl_global->err ()->error2 (UTL_Error::EIDL_MULTIPLE_BRANCH,
                                  this,
                                  t);
      return 0;
    }

  // If branch with same field name exists, complain.
  if ((d = this->lookup_for_add (t, false)) != 0)
    {
      if (!can_be_redefined (d))
        {
          idl_global->err ()->error3 (UTL_Error::EIDL_REDEF,
                                      t,
                                      this,
                                      d);
          return 0;
        }

      if (this->referenced (d, t->local_name ()))
        {
          idl_global->err ()->error3 (UTL_Error::EIDL_DEF_USE,
                                      t,
                                      this,
                                      d);
          return 0;
        }

      if (t->has_ancestor (d))
        {
          idl_global->err ()->redefinition_in_scope (t,
                                                     d);
          return 0;
        }
    }

  // Add it to scope.
  this->add_to_scope (t);

  // If we have an enum discriminator, add the label names to
  // the name_referenced list before we add the union branch,
  // so a branch name clash with a label name will be caught.
  if (this->pd_udisc_type == AST_Expression::EV_enum)
    {
      t->add_labels (this);
    }

  // Add it to set of locally referenced symbols.
  this->add_to_referenced (t,
                           false,
                           t->local_name ());

  AST_Type *ft = t->field_type ();
  UTL_ScopedName *mru = ft->last_referenced_as ();

  if (mru != 0)
    {
      this->add_to_referenced (ft,
                               false,
                               mru->first_component ());
    }

  this->fields_.enqueue_tail (t);

  return t;
}

// Add this AST_Union (manifest union type) to this scope.
AST_Union *
AST_Union::fe_add_union (AST_Union *t)
{
  AST_Decl *d = 0;

  // Already defined and cannot be redefined? Or already used?
  if ((d = this->lookup_for_add (t, false)) != 0)
    {
      if (!can_be_redefined (d))
        {
          idl_global->err ()->error3 (UTL_Error::EIDL_REDEF,
                                      t,
                                      this,
                                      d);
          return 0;
        }

      if (this->referenced (d, t->local_name ()))
        {
          idl_global->err ()->error3 (UTL_Error::EIDL_DEF_USE,
                                      t,
                                      this,
                                      d);
          return 0;
        }

      if (t->has_ancestor (d))
        {
          idl_global->err ()->redefinition_in_scope (t,
                                                     d);
          return 0;
        }
    }

  // Add it to local types.
  this->add_to_local_types (t);

  // Add it to set of locally referenced symbols.
  this->add_to_referenced (t,
                           false,
                           t->local_name ());

  return t;
}

// Add this AST_Structure node (manifest struct type) to this scope.
AST_Structure *
AST_Union::fe_add_structure (AST_Structure *t)
{
  AST_Decl *d = 0;

  // Already defined and cannot be redefined? Or already used?
  if ((d = this->lookup_for_add (t, false)) != 0)
    {
      if (!can_be_redefined (d))
        {
          idl_global->err ()->error3 (UTL_Error::EIDL_REDEF,
                                      t,
                                      this,
                                      d);
          return 0;
        }

      if (this->referenced (d, t->local_name ()))
        {
          idl_global->err ()->error3 (UTL_Error::EIDL_DEF_USE,
                                      t,
                                      this,
                                      d);
          return 0;
        }

      if (t->has_ancestor (d))
        {
          idl_global->err ()->redefinition_in_scope (t,
                                                     d);
          return 0;
        }
    }

  // Add it to local types.
  this->add_to_local_types (t);

  // Add it to set of locally referenced symbols.
  this->add_to_referenced (t,
                           false,
                           t->local_name ());

  return t;
}

// Add this AST_Enum node (manifest enum type) to this scope.
AST_Enum *
AST_Union::fe_add_enum (AST_Enum *t)
{
  AST_Decl *d = 0;

  // Already defined and cannot be redefined? Or already used?
  if ((d = this->lookup_for_add (t, false)) != 0)
    {
      if (!can_be_redefined (d))
        {
          idl_global->err ()->error3 (UTL_Error::EIDL_REDEF,
                                      t,
                                      this,
                                      d);
          return 0;
        }

      if (this->referenced (d, t->local_name ()))
        {
          idl_global->err ()->error3 (UTL_Error::EIDL_DEF_USE,
                                      t,
                                      this,
                                      d);
          return 0;
        }

      if (t->has_ancestor (d))
        {
          idl_global->err ()->redefinition_in_scope (t,
                                                     d);
          return 0;
        }
    }

  // Add it to local types.
  this->add_to_local_types (t);

  // Add it to set of locally referenced symbols.
  this->add_to_referenced (t,
                           false,
                           t->local_name ());

  return t;
}

// Add this AST_EnumVal node (enumerator declaration) to this scope.
// This is done to conform to the C++ scoping rules which declare
// enumerators in the enclosing scope (in addition to declaring them
// in the enum itself).
AST_EnumVal *
AST_Union::fe_add_enum_val (AST_EnumVal *t)
{
  AST_Decl *d = 0;

  // Already defined and cannot be redefined? Or already used?
  if ((d = this->lookup_for_add (t, false)) != 0)
    {
      if (!can_be_redefined (d))
        {
          idl_global->err ()->error3 (UTL_Error::EIDL_REDEF,
                                      t,
                                      this,
                                      d);
          return 0;
        }

      if (this->referenced (d, t->local_name ()))
        {
          idl_global->err ()->error3 (UTL_Error::EIDL_DEF_USE,
                                      t,
                                      this,
                                      d);
          return 0;
        }

      if (t->has_ancestor (d))
        {
          idl_global->err ()->redefinition_in_scope (t,
                                                     d);
          return 0;
        }
    }

  // Add it to scope.
  this->add_to_scope (t);

  // Add it to set of locally referenced symbols.
  this->add_to_referenced (t,
                           false,
                           t->local_name ());

  return t;
}

// Dump this AST_Union node to the ostream o.
void
AST_Union::dump (ACE_OSTREAM_TYPE &o)
{
  o << "union ";
  this->local_name ()->dump (o);
  o << " switch (";
  this->pd_disc_type->local_name ()->dump (o);
  o << ") {\n";
  UTL_Scope::dump (o);
  idl_global->indent ()->skip_to (o);
  o << "}";
}

// Compute the size type of the node in question.
int
AST_Union::compute_size_type (void)
{
  for (UTL_ScopeActiveIterator si (this, UTL_Scope::IK_decls);
       !si.is_done ();
       si.next ())
    {
      // Get the next AST decl node.
      AST_Decl *d = si.item ();

      if (d->node_type () == AST_Decl::NT_enum_val)
        {
          continue;
        }

      AST_Field *f = AST_Field::narrow_from_decl (d);

      if (f != 0)
        {
          AST_Type *t = f->field_type ();
          // Our sizetype depends on the sizetype of our members. Although
          // previous value of sizetype may get overwritten, we are
          // guaranteed by the "size_type" call that once the value reached
          // be_decl::VARIABLE, nothing else can overwrite it.
          this->size_type (t->size_type ());
        }
      else
        {
          ACE_DEBUG ((LM_DEBUG,
                      "WARNING (%N:%l) be_union::compute_size_type - "
                      "narrow_from_decl returned 0\n"));
        }
    }

  return 0;
}

int
AST_Union::ast_accept (ast_visitor *visitor)
{
  return visitor->visit_union (this);
}

// Data accessors.

AST_ConcreteType *
AST_Union::disc_type (void)
{
  return this->pd_disc_type;
}

AST_Expression::ExprType
AST_Union::udisc_type (void)
{
  return this->pd_udisc_type;
}

// Narrowing.
IMPL_NARROW_METHODS1(AST_Union, AST_Structure)
IMPL_NARROW_FROM_DECL(AST_Union)
IMPL_NARROW_FROM_SCOPE(AST_Union)