if arenaBase < zeroedBase {
			// We extended into the non-zeroed part of the
			// arena, so this region needs to be zeroed before use.
			//
			// zeroedBase is monotonically increasing, so if we see this now then
			// we can be sure we need to zero this memory region.
			//
			// We still need to update zeroedBase for this arena, and
			// potentially more arenas.
			needZero = true
		}

func (s bySymValue) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
func (s bySymValue) Less(i, j int) bool { return s[i].v < s[j].v }

// SortSub walks through the sub-symbols for 's' and sorts them
// in place by increasing value. Return value is the new
// sub symbol for the specified outer symbol.
func (l *Loader) SortSub(s Sym) Sym {

	if s == 0 || l.sub[s] == 0 {
		return s
	}