public void AddResumePoint (ResumableStatement stmt, int pc)
{
if (resume_points == null) {
resume_points = new List<ResumableStatement> ();
first_resume_pc = pc;
}
if (pc != first_resume_pc + resume_points.Count)
throw new InternalErrorException ("missed an intervening AddResumePoint?");
resume_points.Add (stmt);
}