init.c

GCC编译器源代码

    {
      dont_use_this = 1;
      decl = build1 (NOP_EXPR, build_pointer_type (type), error_mark_node);
    }
  else
    {
      tree olddecl = current_class_ptr;
      tree oldtype = TREE_TYPE (TREE_TYPE (olddecl));
      if (oldtype != type)
	{
	  tree newtype = build_type_variant (type, TYPE_READONLY (oldtype),
					     TYPE_VOLATILE (oldtype));
	  decl = convert_force (build_pointer_type (newtype), olddecl, 0);
	}
      else
	decl = olddecl;
    }

  decl = build_indirect_ref (decl, NULL_PTR);

  if (method_name == constructor_name (type)
      || method_name == constructor_name_full (type))
    return build_functional_cast (type, parmlist);
  if (t = lookup_fnfields (basetype_path, method_name, 0))
    return build_method_call (decl, 
			      TREE_CODE (name) == TEMPLATE_ID_EXPR
			      ? name : method_name,
			      parmlist, basetype_path,
			      LOOKUP_NORMAL|LOOKUP_NONVIRTUAL);
  if (TREE_CODE (name) == IDENTIFIER_NODE
      && ((t = lookup_field (TYPE_BINFO (type), name, 1, 0))))
    {
      if (t == error_mark_node)
	return error_mark_node;
      if (TREE_CODE (t) == FIELD_DECL)
	{
	  if (dont_use_this)
	    {
	      cp_error ("invalid use of non-static field `%D'", t);
	      return error_mark_node;
	    }
	  decl = build (COMPONENT_REF, TREE_TYPE (t), decl, t);
	}
      else if (TREE_CODE (t) == VAR_DECL)
	decl = t;
      else
	{
	  cp_error ("invalid use of member `%D'", t);
	  return error_mark_node;
	}
      if (TYPE_LANG_SPECIFIC (TREE_TYPE (decl))
	  && TYPE_OVERLOADS_CALL_EXPR (TREE_TYPE (decl)))
	return build_opfncall (CALL_EXPR, LOOKUP_NORMAL, decl, parmlist, NULL_TREE);
      return build_function_call (decl, parmlist);
    }
  else
    {
      cp_error ("no method `%T::%D'", type, name);
      return error_mark_node;
    }
}

/* Build a reference to a member of an aggregate.  This is not a
   C++ `&', but really something which can have its address taken,
   and then act as a pointer to member, for example TYPE :: FIELD
   can have its address taken by saying & TYPE :: FIELD.

   @@ Prints out lousy diagnostics for operator <typename>
   @@ fields.

   @@ This function should be rewritten and placed in search.c.  */

tree
build_offset_ref (type, name)
     tree type, name;
{
  tree decl, fnfields, fields, t = error_mark_node;
  tree basebinfo = NULL_TREE;
  int dtor = 0;

  if (type == std_node)
    return do_scoped_id (name, 0);

  if (processing_template_decl)
    return build_min_nt (SCOPE_REF, type, name);

  /* Handle namespace names fully here.  */
  if (TREE_CODE (type) == IDENTIFIER_NODE
      && get_aggr_from_typedef (type, 0) == 0)
    {
      tree ns = lookup_name (type, 0);
      tree val;
      if (ns && TREE_CODE (ns) == NAMESPACE_DECL)
	{
	  val = lookup_namespace_name (ns, name);
	  if (val)
	    return val;
	  cp_error ("namespace `%D' has no member named `%D'", ns, name);
	  return error_mark_node;
	}
    }

  if (type == NULL_TREE || ! is_aggr_type (type, 1))
    return error_mark_node;

  if (TREE_CODE (name) == BIT_NOT_EXPR)
    {
      dtor = 1;
      name = TREE_OPERAND (name, 0);
    }

  if (name == constructor_name_full (type))
    name = constructor_name (type);

  if (TYPE_SIZE (complete_type (type)) == 0)
    {
      if (type == current_class_type)
	t = IDENTIFIER_CLASS_VALUE (name);
      else
	t = NULL_TREE;
      if (t == 0)
	{
	  cp_error ("incomplete type `%T' does not have member `%D'", type,
		      name);
	  return error_mark_node;
	}
      if (TREE_CODE (t) == TYPE_DECL || TREE_CODE (t) == VAR_DECL
	  || TREE_CODE (t) == CONST_DECL)
	{
	  mark_used (t);
	  return t;
	}
      if (TREE_CODE (t) == FIELD_DECL)
	sorry ("use of member in incomplete aggregate type");
      else if (TREE_CODE (t) == FUNCTION_DECL)
	sorry ("use of member function in incomplete aggregate type");
      else
	my_friendly_abort (52);
      return error_mark_node;
    }

  if (current_class_type == 0
      || get_base_distance (type, current_class_type, 0, &basebinfo) == -1)
    {
      basebinfo = TYPE_BINFO (type);
      decl = build1 (NOP_EXPR, type, error_mark_node);
    }
  else if (current_class_ptr == 0)
    decl = build1 (NOP_EXPR, type, error_mark_node);
  else
    decl = current_class_ref;

  if (constructor_name (BINFO_TYPE (basebinfo)) == name)
    if (dtor)
      name = dtor_identifier;
    else
      name = ctor_identifier;
  else
    if (dtor)
      my_friendly_abort (999);

    
  fnfields = lookup_fnfields (basebinfo, name, 1);
  fields = lookup_field (basebinfo, name, 0, 0);

  if (fields == error_mark_node || fnfields == error_mark_node)
    return error_mark_node;

  /* A lot of this logic is now handled in lookup_field and
     lookup_fnfield.  */
  if (fnfields)
    {
      extern int flag_save_memoized_contexts;
      basebinfo = TREE_PURPOSE (fnfields);

      /* Go from the TREE_BASELINK to the member function info.  */
      t = TREE_VALUE (fnfields);

      if (DECL_CHAIN (t) == NULL_TREE)
	{
	  tree access;

	  /* unique functions are handled easily.  */
	  access = compute_access (basebinfo, t);
	  if (access == access_protected_node)
	    {
	      cp_error_at ("member function `%#D' is protected", t);
	      error ("in this context");
	      return error_mark_node;
	    }
	  if (access == access_private_node)
	    {
	      cp_error_at ("member function `%#D' is private", t);
	      error ("in this context");
	      return error_mark_node;
	    }
	  mark_used (t);
	  return build (OFFSET_REF, TREE_TYPE (t), decl, t);
	}

      /* FNFIELDS is most likely allocated on the search_obstack,
	 which will go away after this class scope.  If we need
	 to save this value for later (either for memoization
	 or for use as an initializer for a static variable), then
	 do so here.

	 ??? The smart thing to do for the case of saving initializers
	 is to resolve them before we're done with this scope.  */
      if (!TREE_PERMANENT (fnfields)
	  && ((flag_save_memoized_contexts && global_bindings_p ())
	      || ! allocation_temporary_p ()))
	fnfields = copy_list (fnfields);

      t = build_tree_list (error_mark_node, fnfields);
      TREE_TYPE (t) = build_offset_type (type, unknown_type_node);
      return t;
    }

  /* Now that we know we are looking for a field, see if we
     have access to that field.  Lookup_field will give us the
     error message.  */

  t = lookup_field (basebinfo, name, 1, 0);

  if (t == error_mark_node)
    return error_mark_node;

  if (t == NULL_TREE)
    {
      cp_error ("`%D' is not a member of type `%T'", name, type);
      return error_mark_node;
    }

  if (TREE_CODE (t) == TYPE_DECL)
    {
      TREE_USED (t) = 1;
      return t;
    }
  /* static class members and class-specific enum
     values can be returned without further ado.  */
  if (TREE_CODE (t) == VAR_DECL || TREE_CODE (t) == CONST_DECL)
    {
      mark_used (t);
      return convert_from_reference (t);
    }

  if (TREE_CODE (t) == FIELD_DECL && DECL_BIT_FIELD (t))
    {
      cp_error ("illegal pointer to bit field `%D'", t);
      return error_mark_node;
    }

  /* static class functions too.  */
  if (TREE_CODE (t) == FUNCTION_DECL
      && TREE_CODE (TREE_TYPE (t)) == FUNCTION_TYPE)
    my_friendly_abort (53);

  /* In member functions, the form `type::name' is no longer
     equivalent to `this->type::name', at least not until
     resolve_offset_ref.  */
  return build (OFFSET_REF, build_offset_type (type, TREE_TYPE (t)), decl, t);
}

/* If a OFFSET_REF made it through to here, then it did
   not have its address taken.  */

tree
resolve_offset_ref (exp)
     tree exp;
{
  tree type = TREE_TYPE (exp);
  tree base = NULL_TREE;
  tree member;
  tree basetype, addr;

  if (TREE_CODE (exp) == TREE_LIST)
    return build_unary_op (ADDR_EXPR, exp, 0);

  if (TREE_CODE (exp) == OFFSET_REF)
    {
      member = TREE_OPERAND (exp, 1);
      base = TREE_OPERAND (exp, 0);
    }
  else
    {
      my_friendly_assert (TREE_CODE (type) == OFFSET_TYPE, 214);
      if (TYPE_OFFSET_BASETYPE (type) != current_class_type)
	{
	  error ("object missing in use of pointer-to-member construct");
	  return error_mark_node;
	}
      member = exp;
      type = TREE_TYPE (type);
      base = current_class_ref;
    }

  if ((TREE_CODE (member) == VAR_DECL
       && ! TYPE_PTRMEMFUNC_P (TREE_TYPE (member)))
      || TREE_CODE (TREE_TYPE (member)) == FUNCTION_TYPE
      || TREE_CODE (TREE_TYPE (member)) == METHOD_TYPE)
    {
      /* These were static members.  */
      if (mark_addressable (member) == 0)
	return error_mark_node;
      return member;
    }

  if (TREE_CODE (TREE_TYPE (member)) == POINTER_TYPE
      && TREE_CODE (TREE_TYPE (TREE_TYPE (member))) == METHOD_TYPE)
    return member;

  /* Syntax error can cause a member which should
     have been seen as static to be grok'd as non-static.  */
  if (TREE_CODE (member) == FIELD_DECL && current_class_ref == NULL_TREE)
    {
      if (TREE_ADDRESSABLE (member) == 0)
	{
	  cp_error_at ("member `%D' is non-static but referenced as a static member",
		       member);
	  error ("at this point in file");
	  TREE_ADDRESSABLE (member) = 1;
	}
      return error_mark_node;
    }

  /* The first case is really just a reference to a member of `this'.  */
  if (TREE_CODE (member) == FIELD_DECL
      && (base == current_class_ref
	  || (TREE_CODE (base) == NOP_EXPR
	      && TREE_OPERAND (base, 0) == error_mark_node)))
    {
      tree basetype_path, access;

      if (TREE_CODE (exp) == OFFSET_REF && TREE_CODE (type) == OFFSET_TYPE)
	basetype = TYPE_OFFSET_BASETYPE (type);
      else
	basetype = DECL_CONTEXT (member);

      base = current_class_ptr;
      
      if (get_base_distance (basetype, TREE_TYPE (TREE_TYPE (base)), 0, &basetype_path) < 0)
	{
	  error_not_base_type (basetype, TREE_TYPE (TREE_TYPE (base)));
	  return error_mark_node;
	}
      addr = convert_pointer_to (basetype, base);
      access = compute_access (basetype_path, member);
      if (access == access_public_node)
	return build (COMPONENT_REF, TREE_TYPE (member),
		      build_indirect_ref (addr, NULL_PTR), member);
      if (access == access_protected_node)
	{
	  cp_error_at ("member `%D' is protected", member);
	  error ("in this context");
	  return error_mark_node;
	}
      if (access == access_private_node)
	{
	  cp_error_at ("member `%D' is private", member);
	  error ("in this context");
	  return error_mark_node;
	}
      my_friendly_abort (55);
    }

  /* Ensure that we have an object.  */
  if (TREE_CODE (base) == NOP_EXPR
      && TREE_OPERAND (base, 0) == error_mark_node)
    addr = error_mark_node;
  else
    {
      /* If this is a reference to a member function, then return the
	 address of the member function (which may involve going
	 through the object's vtable), otherwise, return an expression
	 for the dereferenced pointer-to-member construct.  */
      addr = build_unary_op (ADDR_EXPR, base, 0);
    }

  if (TREE_CODE (TREE_TYPE (member)) == OFFSET_TYPE)
    {
      if (addr == error_mark_node)
	{
	  cp_error ("object missing in `%E'", exp);
	  return error_mark_node;
	}

      basetype = TYPE_OFFSET_BASETYPE (TREE_TYPE (member));
      addr = convert_pointer_to (basetype, addr);
      member = cp_convert (ptrdiff_type_node,
			   build_unary_op (ADDR_EXPR, member, 0));
      
      /* Pointer to data members are offset by one, so that a null
	 pointer with a real value of 0 is distinguishable from an
	 offset of the first member of a structure.  */
      member = build_binary_op (MINUS_EXPR, member,
				cp_convert (ptrdiff_type_node, integer_one_node),
				0);

      return build1 (INDIRECT_REF, type,
		     build (PLUS_EXPR, build_pointer_type (type),
			    addr, member));
    }
  else if (TYPE_PTRMEMFUNC_P (TREE_TYPE (member)))
    {
      return get_member_function_from_ptrfunc (&addr, member);
    }
  my_friendly_abort (56);
  /* NOTREACHED */
  return NULL_TREE;
}

/* Return either DECL or its known constant value (if it has one).  */

tree
decl_constant_value (decl)
     tree decl;
{
  if (! TREE_THIS_VOLATILE (decl)
#if 0
      /* These may be necessary for C, but they break C++.  */
      ! TREE_PUBLIC (decl)
      /* Don't change a variable array bound or initial value to a constant
	 in a place where a variable is invalid.  */
      && ! pedantic
#endif /* 0 */
      && DECL_INITIAL (decl) != 0
      && DECL_INITIAL (decl) != error_mark_node
      /* This is invalid if initial value is not constant.
	 If it has either a function call, a memory reference,
	 or a variable, then re-evaluating it could give different results.  */
      && TREE_CONSTANT (DECL_INITIAL (decl))
      /* Check for cases where this is sub-optimal, even though valid.  */
      && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR
#if 0
      /* We must allow this to work outside of functions so that
	 static constants can be used for array sizes.  */