// The location of each known slot, indexed by SlotID.
	slots []VarLoc
	// The slots present in each register, indexed by register number.
	registers [][]SlotID
}

// reset fills state with the live variables from live.
func (state *stateAtPC) reset(live abt.T) {
	slots, registers := state.slots, state.registers
	for i := range slots {
		slots[i] = VarLoc{}
	}
	for i := range registers {

// countRule increments Func.ruleMatches[key].
// If Func.ruleMatches is non-nil at the end
// of compilation, it will be printed to stdout.
// This is intended to make it easier to find which functions
// which contain lots of rules matches when developing new rules.
func countRule(v *Value, key string) bool {
	f := v.Block.Func
	if f.ruleMatches == nil {
		f.ruleMatches = make(map[string]int)
	}
	f.ruleMatches[key]++