cp-method.c

早期freebsd实现

      try_second = 0;
      break;

    case POSTDECREMENT_EXPR:
      code = PREDECREMENT_EXPR;
      binary_is_unary = 1;
      try_second = 0;
      break;

    case PREDECREMENT_EXPR:
    case POSTINCREMENT_EXPR:
    case COMPONENT_REF:
      binary_is_unary = 1;
      try_second = 0;
      break;

      /* ARRAY_REFs and CALL_EXPRs must overload successfully.
	 If they do not, return error_mark_node instead of NULL_TREE.  */
    case ARRAY_REF:
      if (xarg2 == error_mark_node)
	return error_mark_node;
    case CALL_EXPR:
      rval = error_mark_node;
      binary_is_unary = 0;
      try_second = 0;
      break;

    case NEW_EXPR:
      {
	/* For operators `new' (`delete'), only check visibility
	   if we are in a constructor (destructor), and we are
	   allocating for that constructor's (destructor's) type.  */

	fnname = ansi_opname[(int) NEW_EXPR];
	if (flags & LOOKUP_GLOBAL)
	  return build_overload_call (fnname, tree_cons (NULL_TREE, xarg2, arg3),
				      flags & LOOKUP_COMPLAIN, 0);

	if (current_function_decl == NULL_TREE
	    || !DECL_CONSTRUCTOR_P (current_function_decl)
	    || current_class_type != TYPE_MAIN_VARIANT (type1))
	  flags = LOOKUP_COMPLAIN;
	rval = build_method_call (build1 (NOP_EXPR, xarg1, error_mark_node),
				  fnname, tree_cons (NULL_TREE, xarg2, arg3),
				  NULL_TREE, flags);
	if (rval == error_mark_node)
	  /* User might declare fancy operator new, but invoke it
	     like standard one.  */
	  return rval;

	TREE_TYPE (rval) = xarg1;
	TREE_CALLS_NEW (rval) = 1;
	return rval;
      }
      break;

    case DELETE_EXPR:
      {
	/* See comment above.  */

	fnname = ansi_opname[(int) DELETE_EXPR];
	if (flags & LOOKUP_GLOBAL)
	  return build_overload_call (fnname,
				      tree_cons (NULL_TREE, xarg1,
						 build_tree_list (NULL_TREE, xarg2)),
				      flags & LOOKUP_COMPLAIN, 0);

	if (current_function_decl == NULL_TREE
	    || !DESTRUCTOR_NAME_P (DECL_ASSEMBLER_NAME (current_function_decl))
	    || current_class_type != TYPE_MAIN_VARIANT (type1))
	  flags = LOOKUP_COMPLAIN;
	rval = build_method_call (build1 (NOP_EXPR, TREE_TYPE (xarg1),
					  error_mark_node),
				  fnname, tree_cons (NULL_TREE, xarg1,
						     build_tree_list (NULL_TREE, xarg2)),
				  NULL_TREE, flags);
	/* This happens when the user mis-declares `operator delete'.
	   Should now be impossible.  */
	my_friendly_assert (rval != error_mark_node, 250);
	TREE_TYPE (rval) = void_type_node;
	return rval;
      }
      break;

    default:
      binary_is_unary = 0;
      try_second = tree_code_length [(int) code] == 2;
      if (try_second && xarg2 == error_mark_node)
	return error_mark_node;
      break;
    }

  if (try_second && xarg2 == error_mark_node)
    return error_mark_node;

  /* What ever it was, we do not know how to deal with it.  */
  if (type1 == NULL_TREE)
    return rval;

  if (TREE_CODE (type1) == OFFSET_TYPE)
    type1 = TREE_TYPE (type1);

  if (TREE_CODE (type1) == REFERENCE_TYPE)
    {
      arg1 = convert_from_reference (xarg1);
      type1 = TREE_TYPE (arg1);
    }
  else
    {
      arg1 = xarg1;
    }

  if (!IS_AGGR_TYPE (type1))
    {
      /* Try to fail. First, fail if unary */
      if (! try_second)
	return rval;
      /* Second, see if second argument is non-aggregate. */
      type2 = TREE_TYPE (xarg2);
      if (TREE_CODE (type2) == OFFSET_TYPE)
	type2 = TREE_TYPE (type2);
      if (TREE_CODE (type2) == REFERENCE_TYPE)
	{
	  arg2 = convert_from_reference (xarg2);
	  type2 = TREE_TYPE (arg2);
	}
      else
	{
	  arg2 = xarg2;
	}

      if (!IS_AGGR_TYPE (type2))
	return rval;
      try_second = 0;
    }

  if (try_second)
    {
      /* First arg may succeed; see whether second should.  */
      type2 = TREE_TYPE (xarg2);
      if (TREE_CODE (type2) == OFFSET_TYPE)
	type2 = TREE_TYPE (type2);
      if (TREE_CODE (type2) == REFERENCE_TYPE)
	{
	  arg2 = convert_from_reference (xarg2);
	  type2 = TREE_TYPE (arg2);
	}
      else
	{
	  arg2 = xarg2;
	}

      if (! IS_AGGR_TYPE (type2))
	try_second = 0;
    }

  if (type1 == unknown_type_node
      || (try_second && TREE_TYPE (xarg2) == unknown_type_node))
    {
      /* This will not be implemented in the forseeable future.  */
      return rval;
    }

  if (code == MODIFY_EXPR)
    fnname = ansi_assopname[(int) TREE_CODE (arg3)];
  else
    fnname = ansi_opname[(int) code];

  global_fn = IDENTIFIER_GLOBAL_VALUE (fnname);

  /* This is the last point where we will accept failure.  This
     may be too eager if we wish an overloaded operator not to match,
     but would rather a normal operator be called on a type-converted
     argument.  */

  if (IS_AGGR_TYPE (type1))
    fields1 = lookup_fnfields (TYPE_BINFO (type1), fnname, 0);

  if (fields1 == NULL_TREE && global_fn == NULL_TREE)
    return rval;

  /* If RVAL winds up being `error_mark_node', we will return
     that... There is no way that normal semantics of these
     operators will succeed.  */

  /* This argument may be an uncommitted OFFSET_REF.  This is
     the case for example when dealing with static class members
     which are referenced from their class name rather than
     from a class instance.  */
  if (TREE_CODE (xarg1) == OFFSET_REF
      && TREE_CODE (TREE_OPERAND (xarg1, 1)) == VAR_DECL)
    xarg1 = TREE_OPERAND (xarg1, 1);
  if (try_second && xarg2 && TREE_CODE (xarg2) == OFFSET_REF
      && TREE_CODE (TREE_OPERAND (xarg2, 1)) == VAR_DECL)
    xarg2 = TREE_OPERAND (xarg2, 1);

  if (global_fn)
    flags |= LOOKUP_GLOBAL;

  if (code == CALL_EXPR)
    {
      /* This can only be a member function.  */
      return build_method_call (xarg1, fnname, xarg2,
				NULL_TREE, LOOKUP_NORMAL);
    }
  else if (tree_code_length[(int) code] == 1 || binary_is_unary)
    {
      parms = NULL_TREE;
      rval = build_method_call (xarg1, fnname, NULL_TREE, NULL_TREE, flags);
    }
  else if (code == COND_EXPR)
    {
      parms = tree_cons (0, xarg2, build_tree_list (NULL_TREE, arg3));
      rval = build_method_call (xarg1, fnname, parms, NULL_TREE, flags);
    }
  else if (code == METHOD_CALL_EXPR)
    {
      /* must be a member function.  */
      parms = tree_cons (NULL_TREE, xarg2, arg3);
      return build_method_call (xarg1, fnname, parms, NULL_TREE, LOOKUP_NORMAL);
    }
  else if (fields1)
    {
      parms = build_tree_list (NULL_TREE, xarg2);
      rval = build_method_call (xarg1, fnname, parms, NULL_TREE, flags);
    }
  else
    {
      parms = tree_cons (NULL_TREE, xarg1,
			 build_tree_list (NULL_TREE, xarg2));
      rval = build_overload_call (fnname, parms, flags & LOOKUP_COMPLAIN, 0);
    }

  /* If we did not win, do not lose yet, since type conversion may work.  */
  if (TREE_CODE (rval) == ERROR_MARK)
    {
      if (flags & LOOKUP_COMPLAIN)
	return rval;
      return 0;
    }

  return rval;
}

/* This function takes an identifier, ID, and attempts to figure out what
   it means. There are a number of possible scenarios, presented in increasing
   order of hair:

   1) not in a class's scope
   2) in class's scope, member name of the class's method
   3) in class's scope, but not a member name of the class
   4) in class's scope, member name of a class's variable

   NAME is $1 from the bison rule. It is an IDENTIFIER_NODE.
   VALUE is $$ from the bison rule. It is the value returned by lookup_name ($1)
   yychar is the pending input character (suitably encoded :-).

   As a last ditch, try to look up the name as a label and return that
   address.

   Values which are declared as being of REFERENCE_TYPE are
   automatically dereferenced here (as a hack to make the
   compiler faster).  */

tree
hack_identifier (value, name, yychar)
     tree value, name;
     int yychar;
{
  tree type;

  if (TREE_CODE (value) == ERROR_MARK)
    {
      if (current_class_name)
	{
	  tree fields = lookup_fnfields (TYPE_BINFO (current_class_type), name, 0);
	  if (fields)
	    {
	      tree fndecl;

	      fndecl = TREE_VALUE (fields);
	      my_friendly_assert (TREE_CODE (fndecl) == FUNCTION_DECL, 251);
	      if (DECL_CHAIN (fndecl) == NULL_TREE)
		{
		  warning ("methods cannot be converted to function pointers");
		  return fndecl;
		}
	      else
		{
		  error ("ambiguous request for method pointer `%s'",
			 IDENTIFIER_POINTER (name));
		  return error_mark_node;
		}
	    }
	}
      if (flag_labels_ok && IDENTIFIER_LABEL_VALUE (name))
	{
	  return IDENTIFIER_LABEL_VALUE (name);
	}
      return error_mark_node;
    }

  type = TREE_TYPE (value);
  if (TREE_CODE (value) == FIELD_DECL)
    {
      if (current_class_decl == NULL_TREE)
	{
	  error ("request for member `%s' in static member function",
		 IDENTIFIER_POINTER (DECL_NAME (value)));
	  return error_mark_node;
	}
      TREE_USED (current_class_decl) = 1;
      if (yychar == '(')
	if (! ((TYPE_LANG_SPECIFIC (type)
		&& TYPE_OVERLOADS_CALL_EXPR (type))
	       || (TREE_CODE (type) == REFERENCE_TYPE
		   && TYPE_LANG_SPECIFIC (TREE_TYPE (type))
		   && TYPE_OVERLOADS_CALL_EXPR (TREE_TYPE (type))))
	    && TREE_CODE (type) != FUNCTION_TYPE
	    && TREE_CODE (type) != METHOD_TYPE
	    && (TREE_CODE (type) != POINTER_TYPE
		|| (TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE
		    && TREE_CODE (TREE_TYPE (type)) != METHOD_TYPE)))
	  {
	    error ("component `%s' is not a method",
		   IDENTIFIER_POINTER (name));
	    return error_mark_node;
	  }
      /* Mark so that if we are in a constructor, and then find that
	 this field was initialized by a base initializer,
	 we can emit an error message.  */
      TREE_USED (value) = 1;
      return build_component_ref (C_C_D, name, 0, 1);
    }

  if (TREE_CODE (value) == TREE_LIST)
    {
      tree t = value;
      while (t && TREE_CODE (t) == TREE_LIST)
	{
	  assemble_external (TREE_VALUE (t));
	  TREE_USED (t) = 1;
	  t = TREE_CHAIN (t);
	}
    }
  else
    {
      assemble_external (value);
      TREE_USED (value) = 1;
    }

  if (TREE_CODE_CLASS (TREE_CODE (value)) == 'd' && DECL_NONLOCAL (value))
    {
      if (DECL_CLASS_CONTEXT (value) != current_class_type)
	{
	  tree path;
	  enum visibility_type visibility;
	  register tree context
	    = (TREE_CODE (value) == FUNCTION_DECL && DECL_VIRTUAL_P (value))
	      ? DECL_CLASS_CONTEXT (value)
	      : DECL_CONTEXT (value);

	  get_base_distance (context, current_class_type, 0, &path);
	  visibility = compute_visibility (path, value);
	  if (visibility != visibility_public)
	    {
	      if (TREE_CODE (value) == VAR_DECL)
		error ("static member `%s' is from private base class",
		       IDENTIFIER_POINTER (name));
	      else
		error ("enum `%s' is from private base class",
		       IDENTIFIER_POINTER (name));
	      return error_mark_node;
	    }
	}
      return value;
    }
  if (TREE_CODE (value) == TREE_LIST && TREE_NONLOCAL_FLAG (value))
    {
      if (type == 0)
	{
	  error ("request for member `%s' is ambiguous in multiple inheritance lattice",
		 IDENTIFIER_POINTER (name));
	  return error_mark_node;
	}

      return value;
    }

  if (TREE_CODE (type) == REFERENCE_TYPE)
    {
      my_friendly_assert (TREE_CODE (value) == VAR_DECL
			  || TREE_CODE (value) == PARM_DECL, 252);
      if (DECL_REFERENCE_SLOT (value))
	return DECL_REFERENCE_SLOT (value);
    }
  return value;
}


/* Given an object OF, and a type conversion operator COMPONENT
   build a call to the conversion operator, if a call is requested,
   or return the address (as a pointer to member function) if one is not.

   OF can be a TYPE_DECL or any kind of datum that would normally
   be passed to `build_component_ref'.  It may also be NULL_TREE,
   in which case `current_class_type' and `current_class_decl'
   provide default values.

   BASETYPE_PATH, if non-null, is the path of basetypes
   to go through before we get the the instance of interest.

   PROTECT says whether we apply C++ scoping rules or not.  */
tree
build_component_type_expr (of, component, basetype_path, protect)
     tree of, component, basetype_path;
     int protect;
{
  tree cname = NULL_TREE;
  tree tmp, last;
  tree name;
  int flags = protect ? LOOKUP_NORMAL : LOOKUP_COMPLAIN;

  if (of)
    my_friendly_assert (IS_AGGR_TYPE (TREE_TYPE (of)), 253);
  my_friendly_assert (TREE_CODE (component) == TYPE_EXPR, 254);

  tmp = TREE_OPERAND (component, 0);
  last = NULL_TREE;

  while (tmp)
    {
      switch (TREE_CODE (tmp))
	{
	case CALL_EXPR:
	  if (last)
	    TREE_OPERAND (last, 0) = TREE_OPERAND (tmp, 0);
	  else
	    TREE_OPERAND (component, 0) = TREE_OPERAND (tmp, 0);
	  if (TREE_OPERAND (tmp, 0)
	      && TREE_OPERAND (tmp, 0) != void_list_node)
	    {
	      error ("operator <typename> requires empty parameter list");
	      TREE_OPERAND (tmp, 0) = NULL_TREE;
	    }
	  last = groktypename (build_tree_list (TREE_TYPE (component),
						TREE_OPERAND (component, 0)));
	  name = build_typename_overload (last);
	  TREE_TYPE (name) = last;

	  if (of && TREE_CODE (of) != TYPE_DECL)
	    return build_method_call (of, name, NULL_TREE, NULL_TREE, flags);
	  else if (of)
	    {
	      tree this_this;

	      if (current_class_decl == NULL_TREE)
		{
		  error ("object required for `operator <typename>' call");
		  return error_mark_node;
		}

	      this_this = convert_pointer_to (TREE_TYPE (of), current_class_decl);
	      return build_method_call (this_this, name, NULL_TREE,
					NULL_TREE, flags | LOOKUP_NONVIRTUAL);
	    }
	  else if (current_class_decl)
	    return build_method_call (tmp, name, NULL_TREE, NULL_TREE, flags);

	  error ("object required for `operator <typename>' call");
	  return error_mark_node;

	case INDIRECT_REF:
	case ADDR_EXPR:
	case ARRAY_REF:
	  break;

	case SCOPE_REF:
	  my_friendly_assert (cname == 0, 255);
	  cname = TREE_OPERAND (tmp, 0);
	  tmp = TREE_OPERAND (tmp, 1);
	  break;

	default:
	  my_friendly_abort (77);
	}
      last = tmp;
      tmp = TREE_OPERAND (tmp, 0);
    }

  last = groktypename (build_tree_list (TREE_TYPE (component), TREE_OPERAND (component, 0)));
  name = build_typename_overload (last);
  TREE_TYPE (name) = last;
  if (of && TREE_CODE (of) == TYPE_DECL)
    {
      if (cname == NULL_TREE)
	{
	  cname = DECL_NAME (of);
	  of = NULL_TREE;
	}
      else my_friendly_assert (cname == DECL_NAME (of), 256);
    }

  if (of)
    {
      tree this_this;

      if (current_class_decl == NULL_TREE)
	{
	  error ("object required for `operator <typename>' call");
	  return error_mark_node;
	}

      this_this = convert_pointer_to (TREE_TYPE (of), current_class_decl);
      return build_component_ref (this_this, name, 0, protect);
    }
  else if (cname)
    return build_offset_ref (cname, name);
  else if (current_class_name)
    return build_offset_ref (current_class_name, name);

  error ("object required for `operator <typename>' member reference");
  return error_mark_node;
}