Baby’s First Garbage Collector - Sweep

gc.c

void sweep(VM* vm) {
  Object* object = vm->firstObject;  // vm->firstObject might be a dangling pointer after this :/
  while (object) {
    if (!object->marked) {
      /* This object wasn't reached, so remove it from the list
         and free it. */
      Object* unreached = object;

      object = unreached->next;
      free(unreached);
    } else {
      /* This object was reached, so unmark it (for the next GC)
         and move on to the next. */
      object->marked = 0;
      object = object->next;
    }
  }
}