Add a new definition of variable.

        :param SimVariable variable: The variable being defined.
        :param CodeLocation location: Location of the varaible being defined.
        :param int size_threshold: The maximum bytes to consider for the variable.
        :return: True if the definition was new, False otherwise
        :rtype: bool

def add_def(self, variable, location, size_threshold=32):
        """
        Add a new definition of variable.

        :param SimVariable variable: The variable being defined.
        :param CodeLocation location: Location of the varaible being defined.
        :param int size_threshold: The maximum bytes to consider for the variable.
        :return: True if the definition was new, False otherwise
        :rtype: bool
        """

        new_defs_added = False

        if isinstance(variable, SimRegisterVariable):
            if variable.reg is None:
                l.warning('add_def: Got a None for a SimRegisterVariable. Consider fixing.')
                return new_defs_added

            size = min(variable.size, size_threshold)
            offset = variable.reg
            while offset < variable.reg + size:
                if location not in self._register_map[offset]:
                    new_defs_added = True
                self._register_map[offset].add(location)
                offset += 1

            self._defs[variable].add(location)

        elif isinstance(variable, SimMemoryVariable):
            size = min(variable.size, size_threshold)
            offset = variable.addr
            while offset < variable.addr + size:
                if location not in self._memory_map[offset]:
                    new_defs_added = True
                self._memory_map[offset].add(location)
                offset += 1

            self._defs[variable].add(location)

        else:
            l.error('Unsupported variable type "%s".', type(variable))

        return new_defs_added