// hide pointers from the GC. Use with care and sparingly.
// It is safe to use with values not found in the Go heap.
// Prefer CompareAndSwap instead.
//
//go:nosplit
func (p *Pointer[T]) CompareAndSwapNoWB(old, new *T) bool {
	return p.u.CompareAndSwapNoWB(unsafe.Pointer(old), unsafe.Pointer(new))
}

// CompareAndSwap atomically (with respect to other methods)
// compares u's value with old, and if they're equal,

func atomic_storePointer(ptr *unsafe.Pointer, new unsafe.Pointer) {
	atomicstorep(unsafe.Pointer(ptr), new)
}

// atomic_casPointer is the implementation of runtime/internal/UnsafePointer.CompareAndSwap
// (like CompareAndSwapNoWB but with the write barrier).
//
//go:nosplit
//go:linkname atomic_casPointer internal/runtime/atomic.casPointer
func atomic_casPointer(ptr *unsafe.Pointer, old, new unsafe.Pointer) bool {
	if writeBarrier.enabled {

			// much activity, or the map gets big and races to insert on
			// the same node are much less likely.
			if newNode == nil {
				newNode = tab.newTraceMapNode(data, size, hash, tab.seq.Add(1))
			}
			if m.CompareAndSwapNoWB(nil, unsafe.Pointer(newNode)) {
				return newNode.id, true
			}
			// Reload n. Because pointers are only stored once,
			// we must have lost the race, and therefore n is not nil
			// anymore.

func ReadTrace() []byte {
top:
	var buf []byte
	var park bool
	systemstack(func() {
		buf, park = readTrace0()
	})
	if park {
		gopark(func(gp *g, _ unsafe.Pointer) bool {
			if !trace.reader.CompareAndSwapNoWB(nil, gp) {
				// We're racing with another reader.
				// Wake up and handle this case.
				return false
			}

			if g2 := traceReader(); gp == g2 {
				// New data arrived between unlocking

//
// Nosplit as it is called in a bad stack condition (we know
// morestack would fail).
//
//go:nosplit
//go:nowritebarrierrec
func switchToCrashStack(fn func()) {
	me := getg()
	if crashingG.CompareAndSwapNoWB(nil, me) {
		switchToCrashStack0(fn) // should never return
		abort()
	}
	if crashingG.Load() == me {
		// recursive crashing. too bad.
		writeErrStr("fatal: recursive switchToCrashStack\n")
		abort()