// executed at least once, so it's ok to (effectively) merge
	// together runs derived from different counter modes.
	if d.cmd == percentMode || d.cmd == funcMode || d.cmd == pkglistMode {
		d.cm.SetModeMergePolicy(cmerge.ModeMergeRelaxed)
	}
	if d.cmd == pkglistMode {
		d.pkgpaths = make(map[string]struct{})
	}
	return d
}

// dstate encapsulates state and provides methods for implementing