// live_in[5] = use[5]   U (live_out[5] - def[5])
//            = {%3}     U ({∅} - {∅})            = {%3}
// live_in[4] = use[4]   U (live_out[4] - def[4])
//            = {%1, %2} U ({%3} - {%3})          = {%1, %2}
// live_in[3] = use[3]   U (live_out[3] - def[3])
//            = {%0, %1} U ({%1, %2} - {%2})      = {%0, %1}
// live_in[2] = use[2]   U (live_out[2] - def[2])

template <typename ClusterOrLaunchOp>
func::FuncOp BuildFunction(llvm::ArrayRef<Value> live_ins, ClusterOrLaunchOp op,
                           SymbolTable* symbol_table, OpBuilder* builder) {
  llvm::SmallVector<Type, 4> operand_types;
  operand_types.reserve(live_ins.size());
  for (Value v : live_ins) operand_types.emplace_back(v.getType());

  auto func_type = builder->getFunctionType(operand_types, op.getResultTypes());

      continue;
    }
    // Gets the live in values of the `op`
    llvm::SetVector<Value> live_ins(op.operand_begin(), op.operand_end());
    getUsedValuesDefinedAbove(op.getRegions(), live_ins);
    // Inserts if any of the `live_ins` depends on the ops in the cluster.
    if (llvm::any_of(live_ins, [&](Value value) {
          Operation* defining_op = value.getDefiningOp();
          if (!defining_op) {

	//	varkill: killed variables (set in block)
	uevar   bitvec.BitVec
	varkill bitvec.BitVec

	// Computed during Liveness.solve using control flow information:
	//
	//	livein: variables live at block entry
	//	liveout: variables live at block exit
	livein  bitvec.BitVec
	liveout bitvec.BitVec
}

// A collection of global state used by liveness analysis.
type liveness struct {
	fn         *ir.Func
	f          *ssa.Func

//  2. parse the nocallback and noescape directives.
func (f *File) ProcessCgoDirectives() {
	linesIn := strings.Split(f.Preamble, "\n")
	linesOut := make([]string, 0, len(linesIn))
	f.NoCallbacks = make(map[string]bool)
	f.NoEscapes = make(map[string]bool)
	for _, line := range linesIn {
		l := strings.TrimSpace(line)
		if len(l) < 5 || l[:4] != "#cgo" || !unicode.IsSpace(rune(l[4])) {

// Active spinning for sync.Mutex.
//
// sync_runtime_canSpin should be an internal detail,
// but widely used packages access it using linkname.
// Notable members of the hall of shame include:
//   - github.com/livekit/protocol
//   - github.com/sagernet/gvisor
//   - gvisor.dev/gvisor
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname sync_runtime_canSpin sync.runtime_canSpin