spill    *Value
	needSlot bool
	isArg    bool
}

// stackalloc allocates storage in the stack frame for
// all Values that did not get a register.
// Returns a map from block ID to the stack values live at the end of that block.
func stackalloc(f *Func, spillLive [][]ID) [][]ID {
	if f.pass.debug > stackDebug {
		fmt.Println("before stackalloc")
		fmt.Println(f.String())
	}
	s := newStackAllocState(f)

		unlock(&stackpool[order].item.mu)
	}
}

// stackalloc allocates an n byte stack.
//
// stackalloc must run on the system stack because it uses per-P
// resources and must not split the stack.
//
//go:systemstack
func stackalloc(n uint32) stack {
	// Stackalloc must be called on scheduler stack, so that we
	// never try to grow the stack during the code that stackalloc runs.
	// Doing so would cause a deadlock (issue 1547).

  bool IsAllocOnly() const { return IsAlloc() && effects_.count() == 1; }
  bool IsReadOnly() const { return IsRead() && effects_.count() == 1; }
  ResourceId GetResourceId() const { return resource_id_; }

  void SetAlloc() { effects_.set(kAlloc); }
  void SetFree() { effects_.set(kFree); }
  void SetRead() { effects_.set(kRead); }
  void SetWrite() { effects_.set(kWrite); }
  void SetUnknownEffect() { effects_.set(); }

				l = l1
				break
			}
		}
	}

	// If that failed, allocate a new logger.
	if l == nil {
		// Use sysAllocOS instead of sysAlloc because we want to interfere
		// with the runtime as little as possible, and sysAlloc updates accounting.
		l = (*dlogger)(sysAllocOS(unsafe.Sizeof(dlogger{})))
		if l == nil {
			throw("failed to allocate debug log")
		}
		l.w.r.data = &l.w.data

		if i > (len(service.Spec.ClusterIPs) - 1) {
			service.Spec.ClusterIPs = append(service.Spec.ClusterIPs, "" /* just a marker */)
		}

		toAlloc[ipFamily] = service.Spec.ClusterIPs[i]
	}

	// allocate
	allocated, err := al.allocIPs(service, toAlloc, dryRun)

	// set if successful
	if err == nil {
		for family, ip := range allocated {
			for i, check := range service.Spec.IPFamilies {

There are three mechanisms for allocating unmanaged memory:

* sysAlloc obtains memory directly from the OS. This comes in whole
  multiples of the system page size, but it can be freed with sysFree.

* persistentalloc combines multiple smaller allocations into a single
  sysAlloc to avoid fragmentation. However, there is no way to free
  persistentalloced objects (hence the name).

			hintList = &h.arenaHints
		}
		v, size := h.sysAlloc(userArenaChunkBytes, hintList, false)
		if size%userArenaChunkBytes != 0 {
			throw("sysAlloc size is not divisible by userArenaChunkBytes")
		}
		if size > userArenaChunkBytes {
			// We got more than we asked for. This can happen if
			// heapArenaSize > userArenaChunkSize, or if sysAlloc just returns

		throw("newosproc")
	}
}

// Version of newosproc that doesn't require a valid G.
//
//go:nosplit
func newosproc0(stacksize uintptr, fn unsafe.Pointer) {
	stack := sysAlloc(stacksize, &memstats.stacks_sys)
	if stack == nil {
		writeErrStr(failallocatestack)
		exit(1)
	}
	// This code "knows" it's being called once from the library

		t.FailNow()
	}
}

type acLink struct {
	x [1 << 20]byte
}

var arenaCollisionSink []*acLink

func TestArenaCollision(t *testing.T) {
	testenv.MustHaveExec(t)

	// Test that mheap.sysAlloc handles collisions with other
	// memory mappings.
	if os.Getenv("TEST_ARENA_COLLISION") != "1" {
		cmd := testenv.CleanCmdEnv(exec.Command(os.Args[0], "-test.run=^TestArenaCollision$", "-test.v"))

	nptr := size / goarch.PtrSize
	if uintptr(len(tmpbuf)) < nptr/8+1 {
		if tmpbuf != nil {
			sysFree(unsafe.Pointer(&tmpbuf[0]), uintptr(len(tmpbuf)), &memstats.other_sys)
		}
		n := nptr/8 + 1
		p := sysAlloc(n, &memstats.other_sys)
		if p == nil {
			throw("heapdump: out of memory")
		}
		tmpbuf = (*[1 << 30]byte)(p)[:n]
	}
	// Convert heap bitmap to pointer bitmap.
	clear(tmpbuf[:nptr/8+1])
	s := spanOf(p)