//
// traceRegionAllocBlock is allocated from non-GC'd memory, so it must not
// contain heap pointers. Writes to pointers to traceRegionAllocBlocks do
// not need write barriers.
type traceRegionAllocBlock struct {
	_ sys.NotInHeap
	traceRegionAllocBlockHeader
	data [traceRegionAllocBlockData]byte
}

type traceRegionAllocBlockHeader struct {
	next *traceRegionAllocBlock
	off  atomic.Uintptr
}

// Callers can keep state in the object but the first word is
// smashed by freeing and reallocating.
//
// Consider marking fixalloc'd types not in heap by embedding
// runtime/internal/sys.NotInHeap.
type fixalloc struct {
	size   uintptr
	first  func(arg, p unsafe.Pointer) // called first time p is returned
	arg    unsafe.Pointer
	list   *mlink

//     get shifted out during iteration, and new nodes will just be appended to the 0th child).
type traceMapNode struct {
	_ sys.NotInHeap

	children [4]atomic.UnsafePointer // *traceMapNode (can't use generics because it's notinheap)
	hash     uintptr
	id       uint64
	data     []byte
}

// stealID steals an ID from the table, ensuring that it will not
// appear in the table anymore.

func PtrDataSize(t *Type) int64 {
	CalcSize(t)
	x := t.ptrBytes
	if t.Kind() == TPTR && t.Elem().NotInHeap() {
		// Note: this is done here instead of when we're setting
		// the ptrBytes field, because at that time (in NewPtr, usually)
		// the NotInHeap bit of the element type might not be set yet.
		x = 0
	}
	return x

type notInHeap struct{ _ sys.NotInHeap }

func (p *notInHeap) add(bytes uintptr) *notInHeap {
	return (*notInHeap)(unsafe.Pointer(uintptr(unsafe.Pointer(p)) + bytes))
}

// computeRZlog computes the size of the redzone.
// Refer to the implementation of the compiler-rt.
func computeRZlog(userSize uintptr) uintptr {
	switch {
	case userSize <= (64 - 16):

		r := sysReserve(nil, b)
		if r == nil {
			throw("failed to reserve page summary memory")
		}

		// Put this reservation into a slice.
		sl := notInHeapSlice{(*notInHeap)(r), 0, entries}
		p.summary[l] = *(*[]pallocSum)(unsafe.Pointer(&sl))
	}
}

// sysGrow performs architecture-dependent operations on heap
// growth for the page allocator, such as mapping in new memory

// per-arena bitmap with a bit for every word in the arena. The mark
// is stored on the bit corresponding to the first word of the marked
// allocation.
type checkmarksMap struct {
	_ sys.NotInHeap
	b [heapArenaBytes / goarch.PtrSize / 8]uint8
}

// If useCheckmark is true, marking of an object uses the checkmark
// bits instead of the standard mark bits.
var useCheckmark = false

	sysStat *sysMemStat
}

func (a *addrRanges) init(sysStat *sysMemStat) {
	ranges := (*notInHeapSlice)(unsafe.Pointer(&a.ranges))
	ranges.len = 0
	ranges.cap = 16
	ranges.array = (*notInHeap)(persistentalloc(unsafe.Sizeof(addrRange{})*uintptr(ranges.cap), goarch.PtrSize, sysStat))
	a.sysStat = sysStat
	a.totalBytes = 0
}

// findSucc returns the first index in a such that addr is

		l.w.varint(-1)
	}

	return l
}

// A dlogger writes to the debug log.
//
// To obtain a dlogger, call dlog(). When done with the dlogger, call
// end().
type dlogger struct {
	_ sys.NotInHeap
	w debugLogWriter

	// allLink is the next dlogger in the allDloggers list.
	allLink *dlogger

	// owned indicates that this dlogger is owned by an M. This is
	// accessed atomically.
	owned atomic.Uint32

// Yes, if the representation is a single pointer.
func IsDirectIface(t *Type) bool {
	switch t.Kind() {
	case TPTR:
		// Pointers to notinheap types must be stored indirectly. See issue 42076.
		return !t.Elem().NotInHeap()
	case TCHAN,
		TMAP,
		TFUNC,
		TUNSAFEPTR:
		return true

	case TARRAY:
		// Array of 1 direct iface type can be direct.