// N.B. Ignore the _Gscan bit. We don't model it in the tracer.
	var tgs traceGoStatus
	switch status &^ _Gscan {
	case _Grunnable:
		tgs = traceGoRunnable
	case _Grunning, _Gcopystack:
		tgs = traceGoRunning
	case _Gsyscall:
		tgs = traceGoSyscall
	case _Gwaiting, _Gpreempted:
		// There are a number of cases where a G might end up in
		// _Gwaiting but it's actually running in a non-preemptive

G_MORIBUND_UNUSED = read_runtime_const("'runtime._Gmoribund_unused'", 5)
G_DEAD = read_runtime_const("'runtime._Gdead'", 6)
G_ENQUEUE_UNUSED = read_runtime_const("'runtime._Genqueue_unused'", 7)
G_COPYSTACK = read_runtime_const("'runtime._Gcopystack'", 8)
G_SCAN = read_runtime_const("'runtime._Gscan'", 0x1000)
G_SCANRUNNABLE = G_SCAN+G_RUNNABLE
G_SCANRUNNING = G_SCAN+G_RUNNING
G_SCANSYSCALL = G_SCAN+G_SYSCALL
G_SCANWAITING = G_SCAN+G_WAITING

	// list.
	_Gdead // 6

	// _Genqueue_unused is currently unused.
	_Genqueue_unused // 7

	// _Gcopystack means this goroutine's stack is being moved. It
	// is not executing user code and is not on a run queue. The
	// stack is owned by the goroutine that put it in _Gcopystack.
	_Gcopystack // 8

	// _Gpreempted means this goroutine stopped itself for a
	// suspendG preemption. It is like _Gwaiting, but nothing is

			//
			// preemptStop may need to be cleared, but
			// doing that here could race with goroutine
			// reuse. Instead, goexit0 clears it.
			return suspendGState{dead: true}

		case _Gcopystack:
			// The stack is being copied. We need to wait
			// until this is done.

		case _Gpreempted:
			// We (or someone else) suspended the G. Claim
			// ownership of it by transitioning it to
			// _Gwaiting.

	// so it must be Grunning (or Gscanrunning).
	casgstatus(gp, _Grunning, _Gcopystack)

	// The concurrent GC will not scan the stack while we are doing the copy since
	// the gp is in a Gcopystack status.
	copystack(gp, newsize)
	if stackDebug >= 1 {
		print("stack grow done\n")
	}
	casgstatus(gp, _Gcopystack, _Grunning)
	gogo(&gp.sched)
}

//go:nosplit
func nilfunc() {

}

var gStatusStrings = [...]string{
	_Gidle:      "idle",
	_Grunnable:  "runnable",
	_Grunning:   "running",
	_Gsyscall:   "syscall",
	_Gwaiting:   "waiting",
	_Gdead:      "dead",
	_Gcopystack: "copystack",
	_Gpreempted: "preempted",
}

func goroutineheader(gp *g) {
	level, _, _ := gotraceback()

	gpstatus := readgstatus(gp)

	isScan := gpstatus&_Gscan != 0

//go:nosplit
func casgcopystack(gp *g) uint32 {
	for {
		oldstatus := readgstatus(gp) &^ _Gscan
		if oldstatus != _Gwaiting && oldstatus != _Grunnable {
			throw("copystack: bad status, not Gwaiting or Grunnable")
		}
		if gp.atomicstatus.CompareAndSwap(oldstatus, _Gcopystack) {
			return oldstatus
		}
	}
}

// casGToPreemptScan transitions gp from _Grunning to _Gscan|_Gpreempted.
//

	gp := getg()
	mysg := acquireSudog()
	mysg.releasetime = 0
	if t0 != 0 {
		mysg.releasetime = -1
	}
	// No stack splits between assigning elem and enqueuing mysg
	// on gp.waiting where copystack can find it.
	mysg.elem = ep
	mysg.waitlink = nil
	mysg.g = gp
	mysg.isSelect = false
	mysg.c = c
	gp.waiting = mysg
	gp.param = nil
	c.sendq.enqueue(mysg)

		casi = int(casei)
		cas = &scases[casi]
		c = cas.c
		sg := acquireSudog()
		sg.g = gp
		sg.isSelect = true
		// No stack splits between assigning elem and enqueuing
		// sg on gp.waiting where copystack can find it.
		sg.elem = cas.elem
		sg.releasetime = 0
		if t0 != 0 {
			sg.releasetime = -1
		}
		sg.c = c
		// Construct waiting list in lock order.
		*nextp = sg
		nextp = &sg.waitlink

		scanframeworker(&u.frame, &state, gcw)
	}

	// Find additional pointers that point into the stack from the heap.
	// Currently this includes defers and panics. See also function copystack.

	// Find and trace other pointers in defer records.
	for d := gp._defer; d != nil; d = d.link {
		if d.fn != nil {
			// Scan the func value, which could be a stack allocated closure.
			// See issue 30453.