// should not be used". x86_64 kernel requires it. Only use it on
	// x86.
	if GOARCH == "386" || GOARCH == "amd64" {
		sa.sa_restorer = abi.FuncPCABI0(sigreturn__sigaction)
	}
	if fn == abi.FuncPCABIInternal(sighandler) { // abi.FuncPCABIInternal(sighandler) matches the callers in signal_unix.go
		if iscgo {
			fn = abi.FuncPCABI0(cgoSigtramp)
		} else {
			fn = abi.FuncPCABI0(sigtramp)
		}
	}
	sa.sa_handler = fn

		throw("unreachable")
	}

	if debugChan {
		print("chansend: chan=", c, "\n")
	}

	if raceenabled {
		racereadpc(c.raceaddr(), callerpc, abi.FuncPCABIInternal(chansend))
	}

	// Fast path: check for failed non-blocking operation without acquiring the lock.
	//
	// After observing that the channel is not closed, we observe that the channel is

// asyncPreempt call.
var asyncPreemptStack = ^uintptr(0)

func init() {
	f := findfunc(abi.FuncPCABI0(asyncPreempt))
	total := funcMaxSPDelta(f)
	f = findfunc(abi.FuncPCABIInternal(asyncPreempt2))
	total += funcMaxSPDelta(f)
	// Add some overhead for return PCs, etc.
	asyncPreemptStack = uintptr(total) + 8*goarch.PtrSize
	if asyncPreemptStack > stackNosplit {

}

func (t rtype) textOff(off textOff) unsafe.Pointer {
	if off == -1 {
		// -1 is the sentinel value for unreachable code.
		// See cmd/link/internal/ld/data.go:relocsym.
		return unsafe.Pointer(abi.FuncPCABIInternal(unreachableMethod))
	}
	base := uintptr(unsafe.Pointer(t.Type))
	var md *moduledata
	for next := &firstmoduledata; next != nil; next = next.next {
		if base >= next.types && base < next.etypes {
			md = next

func IsFuncPCIntrinsic(n *CallExpr) bool {
	if n.Op() != OCALLFUNC || n.Fun.Op() != ONAME {
		return false
	}
	fn := n.Fun.(*Name).Sym()
	return (fn.Name == "FuncPCABI0" || fn.Name == "FuncPCABIInternal") &&
		fn.Pkg.Path == "internal/abi"
}

// IsIfaceOfFunc inspects whether n is an interface conversion from a direct
// reference of a func. If so, it returns referenced Func; otherwise nil.
//

// See the doc comment for deferrangefunc for details.
func deferprocat(fn func(), frame any) {
	head := frame.(*atomic.Pointer[_defer])
	if raceenabled {
		racewritepc(unsafe.Pointer(head), getcallerpc(), abi.FuncPCABIInternal(deferprocat))
	}
	d1 := newdefer()
	d1.fn = fn
	for {
		d1.link = head.Load()
		if d1.link == badDefer() {
			throw("defer after range func returned")
		}
		if head.CompareAndSwap(d1.link, d1) {

	}

	stk := make([]uintptr, 32)
	n := runtime.Callers(skip+1, stk[:])
	stk = stk[:n]
	if len(stk) == 0 {
		// The value for skip is too large, and there's no stack trace to record.
		stk = []uintptr{abi.FuncPCABIInternal(lostProfileEvent)}
	}

	p.mu.Lock()
	defer p.mu.Unlock()
	if p.m[value] != nil {
		panic("pprof: Profile.Add of duplicate value")
	}
	p.m[value] = stk
}

		n = 2
		if inVDSOPage(pc) {
			pc = abi.FuncPCABIInternal(_VDSO) + sys.PCQuantum
		} else if pc > firstmoduledata.etext {
			// "ExternalCode" is better than "etext".
			pc = abi.FuncPCABIInternal(_ExternalCode) + sys.PCQuantum
		}
		stk[0] = pc
		if mp.preemptoff != "" {
			stk[1] = abi.FuncPCABIInternal(_GC) + sys.PCQuantum
		} else {
			stk[1] = abi.FuncPCABIInternal(_System) + sys.PCQuantum
		}
	}

		name := n.Fun.(*ir.Name).Sym().Name
		arg := n.Args[0]
		var wantABI obj.ABI
		switch name {
		case "FuncPCABI0":
			wantABI = obj.ABI0
		case "FuncPCABIInternal":
			wantABI = obj.ABIInternal
		}
		if n.Type() != types.Types[types.TUINTPTR] {
			base.FatalfAt(n.Pos(), "FuncPC intrinsic should return uintptr, got %v", n.Type()) // as expected by typecheck.FuncPC.
		}

func gostartcallfn(gobuf *gobuf, fv *funcval) {
	var fn unsafe.Pointer
	if fv != nil {
		fn = unsafe.Pointer(fv.fn)
	} else {
		fn = unsafe.Pointer(abi.FuncPCABIInternal(nilfunc))
	}
	gostartcall(gobuf, fn, unsafe.Pointer(fv))
}

// isShrinkStackSafe returns whether it's safe to attempt to shrink
// gp's stack. Shrinking the stack is only safe when we have precise