rtti.c

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	goto fail;
      if (TYPE_SIZE (complete_type (TREE_TYPE (type))) == NULL_TREE)
	goto fail;
      break;
      /* else fall through */
    default:
      goto fail;
    }

  /* Apply trivial conversion T -> T& for dereferenced ptrs.  */
  if (ec == RECORD_TYPE)
    {
      exprtype = build_type_variant (exprtype, TREE_READONLY (expr),
				     TREE_THIS_VOLATILE (expr));
      exprtype = build_reference_type (exprtype);
      expr = convert_to_reference (exprtype, expr, CONV_IMPLICIT,
				   LOOKUP_NORMAL, NULL_TREE);
      ec = REFERENCE_TYPE;
    }

  if (tc == REFERENCE_TYPE)
    {
      if (ec != REFERENCE_TYPE)
	goto fail;
      if (TREE_CODE (TREE_TYPE (exprtype)) != RECORD_TYPE)
	goto fail;
      if (TYPE_SIZE (complete_type (TREE_TYPE (exprtype))) == NULL_TREE)
	goto fail;
      if (TREE_READONLY (TREE_TYPE (exprtype))
	  && ! TYPE_READONLY (TREE_TYPE (type)))
	goto fail;
    }

  /* If *type is an unambiguous accessible base class of *exprtype,
     convert statically.  */
  {
    int distance;
    tree path;

    distance = get_base_distance (TREE_TYPE (type), TREE_TYPE (exprtype), 1,
				  &path);
    if (distance >= 0)
      return build_vbase_path (PLUS_EXPR, type, expr, path, 0);
  }

  /* Otherwise *exprtype must be a polymorphic class (have a vtbl).  */
  if (TYPE_VIRTUAL_P (TREE_TYPE (exprtype)))
    {
      tree expr1;
      /* if TYPE is `void *', return pointer to complete object.  */
      if (tc == POINTER_TYPE
	  && TYPE_MAIN_VARIANT (TREE_TYPE (type)) == void_type_node)
	{
	  /* if b is an object, dynamic_cast<void *>(&b) == (void *)&b.  */
	  if (TREE_CODE (expr) == ADDR_EXPR
	      && TREE_CODE (TREE_OPERAND (expr, 0)) == VAR_DECL
	      && TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == RECORD_TYPE)
	    return build1 (NOP_EXPR, type, expr);

	  /* Since expr is used twice below, save it.  */
	  expr = save_expr (expr);

	  expr1 = build_headof (expr);
	  if (TREE_TYPE (expr1) != type)
	    expr1 = build1 (NOP_EXPR, type, expr1);
	  return ifnonnull (expr, expr1);
	}
      else
	{
	  tree retval;
          tree result, td1, td2, td3, elems, expr2;

 	  /* If we got here, we can't convert statically.  Therefore,
	     dynamic_cast<D&>(b) (b an object) cannot succeed.  */
	  if (ec == REFERENCE_TYPE)
	    {
	      if (TREE_CODE (expr) == VAR_DECL
		  && TREE_CODE (TREE_TYPE (expr)) == RECORD_TYPE)
		{
		  cp_warning ("dynamic_cast of `%#D' to `%#T' can never succeed",
			      expr, type);
		  return throw_bad_cast ();
		}
	    }
	  /* Ditto for dynamic_cast<D*>(&b).  */
	  else if (TREE_CODE (expr) == ADDR_EXPR)
	    {
	      tree op = TREE_OPERAND (expr, 0);
	      if (TREE_CODE (op) == VAR_DECL
		  && TREE_CODE (TREE_TYPE (op)) == RECORD_TYPE)
		{
		  cp_warning ("dynamic_cast of `%#D' to `%#T' can never succeed",
			      expr, type);
		  retval = build_int_2 (0, 0); 
		  TREE_TYPE (retval) = type; 
		  return retval;
		}
	    }

	  /* Since expr is used twice below, save it.  */
	  expr = save_expr (expr);

	  expr1 = expr;
	  if (tc == REFERENCE_TYPE)
	    expr1 = build_unary_op (ADDR_EXPR, expr1, 0);

	  /* Build run-time conversion.  */
	  expr2 = build_headof (expr1);

	  if (ec == POINTER_TYPE)
	    td1 = get_tinfo_fn_dynamic (build_indirect_ref (expr, NULL_PTR));
	  else
	    td1 = get_tinfo_fn_dynamic (expr);
	  td1 = decay_conversion (td1);
	  
	  td2 = decay_conversion
	    (get_tinfo_fn (TYPE_MAIN_VARIANT (TREE_TYPE (type))));
	  td3 = decay_conversion
	    (get_tinfo_fn (TYPE_MAIN_VARIANT (TREE_TYPE (exprtype))));

          elems = tree_cons
	    (NULL_TREE, td1, tree_cons
	     (NULL_TREE, td2, tree_cons
	      (NULL_TREE, build_int_2 (1, 0), tree_cons
	       (NULL_TREE, expr2, tree_cons
		(NULL_TREE, td3, tree_cons
		 (NULL_TREE, expr1, NULL_TREE))))));

	  dcast_fn = get_identifier ("__dynamic_cast");
	  if (IDENTIFIER_GLOBAL_VALUE (dcast_fn))
	    dcast_fn = IDENTIFIER_GLOBAL_VALUE (dcast_fn);
	  else
	    {
	      tree tmp;

	      push_obstacks (&permanent_obstack, &permanent_obstack);
	      tmp = tree_cons
		(NULL_TREE, TREE_TYPE (td1), tree_cons
		 (NULL_TREE, TREE_TYPE (td1), tree_cons
		  (NULL_TREE, integer_type_node, tree_cons
		   (NULL_TREE, ptr_type_node, tree_cons
		    (NULL_TREE, TREE_TYPE (td1), tree_cons
		     (NULL_TREE, ptr_type_node, void_list_node))))));
	      tmp = build_function_type (ptr_type_node, tmp);
	      dcast_fn = build_lang_decl (FUNCTION_DECL, dcast_fn, tmp);
	      DECL_EXTERNAL (dcast_fn) = 1;
	      TREE_PUBLIC (dcast_fn) = 1;
	      DECL_ARTIFICIAL (dcast_fn) = 1;
	      pushdecl_top_level (dcast_fn);
	      make_function_rtl (dcast_fn);
	      assemble_external (dcast_fn);
	      pop_obstacks ();
	    }
	  
          result = build_call
	    (dcast_fn, TREE_TYPE (TREE_TYPE (dcast_fn)), elems);

	  if (tc == REFERENCE_TYPE)
	    {
	      expr1 = throw_bad_cast ();
	      expr1 = build_compound_expr
		(expr_tree_cons (NULL_TREE, expr1,
			    build_expr_list (NULL_TREE, cp_convert (type, integer_zero_node))));
	      TREE_TYPE (expr1) = type;
	      result = save_expr (result);
	      return build (COND_EXPR, type, result, result, expr1);
	    }

	  /* Now back to the type we want from a void*.  */
	  result = cp_convert (type, result);
          return ifnonnull (expr, result);
	}
    }

 fail:
  cp_error ("cannot dynamic_cast `%E' (of type `%#T') to type `%#T'",
	    expr, exprtype, type);
  return error_mark_node;
}

tree
build_dynamic_cast (type, expr)
     tree type, expr;
{
  return convert_from_reference (build_dynamic_cast_1 (type, expr));
}

/* Build and initialize various sorts of descriptors.  Every descriptor
   node has a name associated with it (the name created by mangling).
   For this reason, we use the identifier as our access to the __*_desc
   nodes, instead of sticking them directly in the types.  Otherwise we
   would burden all built-in types (and pointer types) with slots that
   we don't necessarily want to use.

   For each descriptor we build, we build a variable that contains
   the descriptor's information.  When we need this info at runtime,
   all we need is access to these variables.

   Note: these constructors always return the address of the descriptor
   info, since that is simplest for their mutual interaction.  */

extern tree const_string_type_node;

/* Build an initializer for a __si_type_info node.  */

static void
expand_si_desc (tdecl, type)
     tree tdecl;
     tree type;
{
  tree t, elems, fn;
  char *name = build_overload_name (type, 1, 1);
  tree name_string = combine_strings (build_string (strlen (name)+1, name));

  type = BINFO_TYPE (TREE_VEC_ELT (TYPE_BINFO_BASETYPES (type), 0));
  expand_expr_stmt (get_typeid_1 (type));
  t = decay_conversion (get_tinfo_var (type));
  elems = tree_cons
    (NULL_TREE, decay_conversion (tdecl), tree_cons
     (NULL_TREE, decay_conversion (name_string), tree_cons
      (NULL_TREE, t, NULL_TREE)));

  fn = get_identifier ("__rtti_si");
  if (IDENTIFIER_GLOBAL_VALUE (fn))
    fn = IDENTIFIER_GLOBAL_VALUE (fn);
  else
    {
      tree tmp;
      push_obstacks (&permanent_obstack, &permanent_obstack);
      tmp = tree_cons
	(NULL_TREE, ptr_type_node, tree_cons
	 (NULL_TREE, const_string_type_node, tree_cons
	  (NULL_TREE, build_pointer_type (type_info_type_node),
	   void_list_node)));
      tmp = build_function_type	(void_type_node, tmp);
  
      fn = build_lang_decl (FUNCTION_DECL, fn, tmp);
      DECL_EXTERNAL (fn) = 1;
      TREE_PUBLIC (fn) = 1;
      DECL_ARTIFICIAL (fn) = 1;
      pushdecl_top_level (fn);
      make_function_rtl (fn);
      assemble_external (fn);
      pop_obstacks ();
    }

  fn = build_call (fn, TREE_TYPE (TREE_TYPE (fn)), elems);
  expand_expr_stmt (fn);
}

/* Build an initializer for a __class_type_info node.  */

static void
expand_class_desc (tdecl, type)
     tree tdecl;
     tree type;
{
  tree name_string;
  tree fn, tmp;
  char *name;

  int i = CLASSTYPE_N_BASECLASSES (type);
  int base_cnt = 0;
  tree binfos = TYPE_BINFO_BASETYPES (type);
#if 0
  /* See code below that used these.  */
  tree vb = CLASSTYPE_VBASECLASSES (type);
  int n_base = i;
#endif
  tree base, elems, access, offset, isvir;
  tree elt, elts = NULL_TREE;
  static tree base_info_type_node;

  if (base_info_type_node == NULL_TREE)
    {
      tree fields [4];

      /* A reasonably close approximation of __class_type_info::base_info */

      push_obstacks (&permanent_obstack, &permanent_obstack);
      base_info_type_node = make_lang_type (RECORD_TYPE);

      /* Actually const __user_type_info * */
      fields [0] = build_lang_field_decl
	(FIELD_DECL, NULL_TREE,
	 build_pointer_type (build_type_variant (type_info_type_node, 1, 0)));
      fields [1] = build_lang_field_decl
	(FIELD_DECL, NULL_TREE, unsigned_intSI_type_node);
      DECL_BIT_FIELD (fields[1]) = 1;
      DECL_FIELD_SIZE (fields[1]) = 29;

      fields [2] = build_lang_field_decl
	(FIELD_DECL, NULL_TREE, boolean_type_node);
      DECL_BIT_FIELD (fields[2]) = 1;
      DECL_FIELD_SIZE (fields[2]) = 1;

      /* Actually enum access */
      fields [3] = build_lang_field_decl
	(FIELD_DECL, NULL_TREE, integer_type_node);
      DECL_BIT_FIELD (fields[3]) = 1;
      DECL_FIELD_SIZE (fields[3]) = 2;

      finish_builtin_type (base_info_type_node, "__base_info", fields,
			   3, ptr_type_node);
      pop_obstacks ();
    }

  while (--i >= 0)
    {
      tree binfo = TREE_VEC_ELT (binfos, i);

      expand_expr_stmt (get_typeid_1 (BINFO_TYPE (binfo)));
      base = decay_conversion (get_tinfo_var (BINFO_TYPE (binfo)));

      if (TREE_VIA_VIRTUAL (binfo))
	{
	  tree t = BINFO_TYPE (binfo);
	  char *name;
	  tree field;

	  name = (char *) alloca (TYPE_NAME_LENGTH (t)+sizeof (VBASE_NAME)+1);
	  sprintf (name, VBASE_NAME_FORMAT, TYPE_NAME_STRING (t));
	  field = lookup_field (type, get_identifier (name), 0, 0);
	  offset = size_binop (FLOOR_DIV_EXPR, 
		DECL_FIELD_BITPOS (field), size_int (BITS_PER_UNIT));
	}
      else
	offset = BINFO_OFFSET (binfo);

      if (TREE_VIA_PUBLIC (binfo))
        access = access_public_node;
      else if (TREE_VIA_PROTECTED (binfo))
	access = access_protected_node;
      else
	access = access_private_node;
      if (TREE_VIA_VIRTUAL (binfo))
	isvir = boolean_true_node;
      else
	isvir = boolean_false_node;

      elt = build
	(CONSTRUCTOR, base_info_type_node, NULL_TREE, tree_cons
	 (NULL_TREE, base, tree_cons
	  (NULL_TREE, offset, tree_cons
	   (NULL_TREE, isvir, tree_cons
	    (NULL_TREE, access, NULL_TREE)))));
      TREE_HAS_CONSTRUCTOR (elt) = TREE_CONSTANT (elt) = TREE_STATIC (elt) = 1;
      elts = expr_tree_cons (NULL_TREE, elt, elts);
      base_cnt++;
    }
#if 0
  i = n_base;
  while (vb)
    {
      tree b;
      access = access_public_node;
      while (--i >= 0)
	{
	  b = TREE_VEC_ELT (binfos, i);
	  if (BINFO_TYPE (vb) == BINFO_TYPE (b) && TREE_VIA_VIRTUAL (b))
	    {
	      if (TREE_VIA_PUBLIC (b))
		access = access_public_node;
	      else if (TREE_VIA_PROTECTED (b))
		access = access_protected_node;
	      else
		access = access_private_node;
	      break;
	    }
	}
      base = build_t_desc (BINFO_TYPE (vb), 1);
      offset = BINFO_OFFSET (vb);
      isvir = build_int_2 (1, 0);

      base_list = expr_tree_cons (NULL_TREE, base, base_list);
      isvir_list = expr_tree_cons (NULL_TREE, isvir, isvir_list);
      acc_list = expr_tree_cons (NULL_TREE, access, acc_list);
      off_list = expr_tree_cons (NULL_TREE, offset, off_list);

      base_cnt++;
      vb = TREE_CHAIN (vb);
    }
#endif

  name = build_overload_name (type, 1, 1);
  name_string = combine_strings (build_string (strlen (name)+1, name));

  {
    tree arrtype = build_array_type (base_info_type_node, NULL_TREE);
    elts = build (CONSTRUCTOR, arrtype, NULL_TREE, elts);
    TREE_HAS_CONSTRUCTOR (elts) = TREE_CONSTANT (elts)
      = TREE_STATIC (elts) = 1;
    complete_array_type (arrtype, elts, 1);
  }

  elems = tree_cons
    (NULL_TREE, decay_conversion (tdecl), tree_cons
     (NULL_TREE, decay_conversion (name_string), tree_cons
      (NULL_TREE, decay_conversion (elts), tree_cons
       (NULL_TREE, cp_convert (sizetype, build_int_2 (base_cnt, 0)),
	NULL_TREE))));

  fn = get_identifier ("__rtti_class");
  if (IDENTIFIER_GLOBAL_VALUE (fn))
    fn = IDENTIFIER_GLOBAL_VALUE (fn);
  else
    {
      push_obstacks (&permanent_obstack, &permanent_obstack);
      tmp = tree_cons
	(NULL_TREE, ptr_type_node, tree_cons
	 (NULL_TREE, const_string_type_node, tree_cons
	  (NULL_TREE, build_pointer_type (base_info_type_node), tree_cons
	   (NULL_TREE, sizetype, void_list_node))));
      tmp = build_function_type	(void_type_node, tmp);
  
      fn = build_lang_decl (FUNCTION_DECL, fn, tmp);
      DECL_EXTERNAL (fn) = 1;
      TREE_PUBLIC (fn) = 1;
      DECL_ARTIFICIAL (fn) = 1;
      pushdecl_top_level (fn);
      make_function_rtl (fn);
      assemble_external (fn);
      pop_obstacks ();
    }

  fn = build_call (fn, TREE_TYPE (TREE_TYPE (fn)), elems);
  expand_expr_stmt (fn);
}

/* Build an initializer for a __pointer_type_info node.  */

static void
expand_ptr_desc (tdecl, type)
     tree tdecl;
     tree type;
{
  tree t, elems, fn;
  char *name = build_overload_name (type, 1, 1);
  tree name_string = combine_strings (build_string (strlen (name)+1, name));

  type = TREE_TYPE (type);
  expand_expr_stmt (get_typeid_1 (type));
  t = decay_conversion (get_tinfo_var (type));
  elems = tree_cons
    (NULL_TREE, decay_conversion (tdecl), tree_cons
     (NULL_TREE, decay_conversion (name_string), tree_cons
      (NULL_TREE, t, NULL_TREE)));

  fn = get_identifier ("__rtti_ptr");
  if (IDENTIFIER_GLOBAL_VALUE (fn))
    fn = IDENTIFIER_GLOBAL_VALUE (fn);
  else
    {
      tree tmp;
      push_obstacks (&permanent_obstack, &permanent_obstack);
      tmp = tree_cons
	(NULL_TREE, ptr_type_node, tree_cons
	 (NULL_TREE, const_string_type_node, tree_cons
	  (NULL_TREE, build_pointer_type (type_info_type_node),
	   void_list_node)));
      tmp = build_function_type	(void_type_node, tmp);
  
      fn = build_lang_decl (FUNCTION_DECL, fn, tmp);
      DECL_EXTERNAL (fn) = 1;
      TREE_PUBLIC (fn) = 1;