add-log-current-defun-function is a variable defined in `add-log.el'.
Its value is

  • This variable may be risky if used as a file-local variable.

If non-nil, function to guess name of surrounding function.
It is called by `add-log-current-defun' with no argument, and
should return the function's name as a string, or nil if point is
outside a function.

You can customize this variable.