// to these types must always fail the `runtime.inheap` check. The type may be used
// for global variables, or for objects in unmanaged memory (e.g., allocated with
// `sysAlloc`, `persistentalloc`, r`fixalloc`, or from a manually-managed span).
//
// Specifically:
//
// 1. `new(T)`, `make([]T)`, `append([]T, ...)` and implicit heap
// allocation of T are disallowed. (Though implicit allocations are

	for _, ai := range mheap_.allArenas {
		arena := mheap_.arenas[ai.l1()][ai.l2()]
		bitmap := arena.checkmarks

		if bitmap == nil {
			// Allocate bitmap on first use.
			bitmap = (*checkmarksMap)(persistentalloc(unsafe.Sizeof(*bitmap), 0, &memstats.gcMiscSys))
			if bitmap == nil {
				throw("out of memory allocating checkmarks bitmap")
			}
			arena.checkmarks = bitmap
		} else {
			// Otherwise clear the existing bitmap.

		v := unsafe.Pointer(f.list)
		f.list = f.list.next
		f.inuse += f.size
		if f.zero {
			memclrNoHeapPointers(v, f.size)
		}
		return v
	}
	if uintptr(f.nchunk) < f.size {
		f.chunk = uintptr(persistentalloc(uintptr(f.nalloc), 0, f.stat))
		f.nchunk = f.nalloc
	}

	v := unsafe.Pointer(f.chunk)
	if f.first != nil {
		f.first(f.arg, v)
	}
	f.chunk = f.chunk + f.size
	f.nchunk -= uint32(f.size)

// outside the Go heap.
// We require lfstack objects to live outside the heap so that
// checkptr passes on the unsafe shenanigans used.
func allocMyNode(data int) *MyNode {
	n := (*MyNode)(PersistentAlloc(unsafe.Sizeof(MyNode{})))
	LFNodeValidate(&n.LFNode)
	n.data = data
	return n
}

func fromMyNode(node *MyNode) *LFNode {
	return (*LFNode)(unsafe.Pointer(node))
}

func toMyNode(node *LFNode) *MyNode {

		}
		// The first word of an interface is a pointer, but we don't
		// treat it as such.
		// 1. If it is a non-empty interface, the pointer points to an itab
		//    which is always in persistentalloc space.
		// 2. If it is an empty interface, the pointer points to a _type.
		//   a. If it is a compile-time-allocated type, it points into
		//      the read-only data section.

		return
	}

	// If the object is pinned, it's safe to store it in C memory. The GC
	// ensures it will not be moved or freed.
	if isPinned(src) {
		return
	}

	// It's OK if writing to memory allocated by persistentalloc.
	// Do this check last because it is more expensive and rarely true.
	// If it is false the expense doesn't matter since we are crashing.
	if inPersistentAlloc(uintptr(unsafe.Pointer(dst))) {
		return
	}