return (*T)(unsafe.Pointer(x ^ 0))
}

// Not all cgocallback frames are actually cgocallback,
// so not all have these arguments. Mark them uintptr so that the GC
// does not misinterpret memory when the arguments are not present.
// cgocallback is not called from Go, only from crosscall2.
// This in turn calls cgocallbackg, which is where we'll find
// pointer-declared arguments.
//

// unset since we're in Go code.
GLOBL zeroTLS<>(SB),RODATA,$const_tlsSize
#endif

// func cgocallback(fn, frame unsafe.Pointer, ctxt uintptr)
// See cgocall.go for more details.
TEXT ·cgocallback(SB),NOSPLIT,$24-24
	NO_LOCAL_POINTERS

	// Skip cgocallbackg, just dropm when fn is nil, and frame is the saved g.
	// It is used to dropm while thread is exiting.
	MOVQ	fn+0(FP), AX
	CMPQ	AX, $0

Brad Fitzpatrick <******@****.***> 1456873066 +0000

typedef struct cb {
        int foo;
} cb;
extern void goCallback();
static inline void *threadFunc(void *p) {
	goCallback();
	return 0;
}
static inline void startThread(cb* c) {
	pthread_t th;
	pthread_create(&th, 0, threadFunc, 0);
}
*/
import "C"

var done chan bool
var racy int

//export goCallback
func goCallback() {
	racy++
	done <- true
}

func main() {

var runtime_inittasks []*initTask

// main_init_done is a signal used by cgocallbackg that initialization
// has been completed. It is made before _cgo_notify_runtime_init_done,
// so all cgo calls can rely on it existing. When main_init is complete,
// it is closed, meaning cgocallbackg can reliably receive from it.
var main_init_done chan bool

//go:linkname main_main main.main
func main_main()

		// The exact function names are not going to be the same.
		t.Skip("skipping for non-gc toolchain")
	}
	pc := make([]uintptr, 100)
	n := 0
	name := []string{
		"runtime.cgocallbackg1",
		"runtime.cgocallbackg",
		"runtime.cgocallback",
		"runtime.systemstack_switch",
		"runtime.cgocall",
		"test._Cfunc_callback",
		"test.nestedCall.func1",
		"test.nestedCall",
		"test.testCallbackCallers",

		// until they have been, because that is where a call to
		// SetCgoTraceback is likely to occur. We are going to wait for Go
		// initialization to be complete anyhow, later, by waiting for
		// main_init_done to be closed in cgocallbackg1. We should wait here
		// instead. See also issue #15943.
		pfn = __atomic_load_n(&cgo_context_function, __ATOMIC_CONSUME);

		__atomic_store_n(&runtime_init_done, done, __ATOMIC_RELEASE);

TEXT crosscall2_trampoline<>(SB),NOSPLIT,$0-0
	JMP	crosscall2(SB)

// Called by C code generated by cmd/cgo.
// func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)
// Saves C callee-saved registers and calls cgocallback with three arguments.
// fn is the PC of a func(a unsafe.Pointer) function.
TEXT crosscall2(SB),NOSPLIT|NOFRAME,$0
	SUB	$(8*9), R13 // Reserve space for the floating point registers.

    pthread_join(th, 0);
}
*/
import "C"

import (
	"fmt"
	"os"
	"runtime"
	"sync/atomic"
	_ "unsafe" // for go:linkname
)

func init() {
	register("CgoCallbackGC", CgoCallbackGC)
}

//export go_callback
func go_callback() {
	if e := extraMInUse.Load(); e == 0 {
		fmt.Printf("in callback extraMInUse got %d want >0\n", e)
		os.Exit(1)
	}

	runtime.GC()
	grow()

	case "Callback":
		testCallback()
	}
	println("OK")
}

func fatal(f string, args ...any) {
	fmt.Fprintln(os.Stderr, fmt.Sprintf(f, args...))
	os.Exit(1)
}

type GoCallback struct{}

func (p *GoCallback) Run() string {
	return "GoCallback.Run"
}

func testCall() {
	c := NewCaller()
	cb := NewCallback()

	c.SetCallback(cb)
	s := c.Call()
	if s != "Callback::run" {