return space.isLive(object)
return space.isReachable(object)
  protected int sanityExpectedRC(ObjectReference object,                                            int sanityRootRC) {    Space space = Space.getSpaceForObject(object);    // Nursery    if (space == Gen.nurserySpace) {      return global().preGCSanity()         ? SanityChecker.UNSURE        : SanityChecker.DEAD;    }    // Immortal spaces    if (space == Gen.immortalSpace || space == Gen.vmSpace) {      return space.isReachable(object)        ? SanityChecker.ALIVE          : SanityChecker.DEAD;    }    // Mature space (nursery collection)    if (ActivePlan.global().isCurrentGCNursery()) {      return SanityChecker.UNSURE;    }    // Mature space (full heap collection)    return space.isLive(object)       ? SanityChecker.ALIVE       : SanityChecker.DEAD;  }