def METHOD_NAME(self, simgr):
    """Prior to stepping the active states, increment the passthrough count on the basic block(s) that will be
    executed next."""
    if self.bb_addrs is None:
        self.bb_addrs = {b.addr for b in self.instance.cfg.nodes()}
    for s in simgr.active:
        for i_addr in s.block().instruction_addrs:
            if i_addr in self.bb_addrs:
                self.passthrough_counts[i_addr] += 1