// the reason for waiting in a backtrace, and is used to compute some metrics.
// Otherwise they're functionally identical.
func runtime_SemacquireMutex(s *uint32, lifo bool, skipframes int)
func runtime_SemacquireRWMutexR(s *uint32, lifo bool, skipframes int)
func runtime_SemacquireRWMutex(s *uint32, lifo bool, skipframes int)

// Semrelease atomically increments *s and notifies a waiting goroutine
// if one is blocked in Semacquire.

func sync_runtime_SemacquireMutex(addr *uint32, lifo bool, skipframes int) {
	semacquire1(addr, lifo, semaBlockProfile|semaMutexProfile, skipframes, waitReasonSyncMutexLock)
}

//go:linkname sync_runtime_SemacquireRWMutexR sync.runtime_SemacquireRWMutexR
func sync_runtime_SemacquireRWMutexR(addr *uint32, lifo bool, skipframes int) {
	semacquire1(addr, lifo, semaBlockProfile|semaMutexProfile, skipframes, waitReasonSyncRWMutexRLock)

	node = toMyNode(LFStackPop(stack))
	if node == nil {
		t.Fatalf("stack is empty")
	}
	if node.data != 43 {
		t.Fatalf("no lifo")
	}

	// Pop another.
	node = toMyNode(LFStackPop(stack))
	if node == nil {
		t.Fatalf("stack is empty")
	}
	if node.data != 42 {
		t.Fatalf("no lifo")
	}

	// Check the stack is empty again.
	if LFStackPop(stack) != nil {
		t.Fatalf("stack is not empty")
	}

	posdegree := f.newSparseSet(f.NumBlocks()) // blocks with positive remaining degree
	defer f.retSparseSet(posdegree)
	// blocks with zero remaining degree. Use slice to simulate a LIFO queue to implement
	// the depth-first topology sorting algorithm.
	var zerodegree []ID
	// LIFO queue. Track the successor blocks of the scheduled block so that when we
	// encounter loops, we choose to schedule the successor block of the most recently
	// scheduled block.

// Check adds a check to a test to ensure there are no leaked goroutines
// To use, simply call leak.Check(t) at the start of a test; Do not call it in defer.
// It is recommended to call this as the first step, as Cleanup is called in LIFO order; this ensures any
// Cleanup's called in the test happen first.
// Any existing goroutines before the test starts are filtered out. This ensures a single test failing doesn't

   * additional exceptions that are thrown after that will be suppressed.
   */
  @Override
  public void close() throws IOException {
    Throwable throwable = thrown;

    // close closeables in LIFO order
    while (!stack.isEmpty()) {
      Closeable closeable = stack.removeFirst();
      try {
        closeable.close();
      } catch (Throwable e) {
        if (throwable == null) {

   * additional exceptions that are thrown after that will be suppressed.
   */
  @Override
  public void close() throws IOException {
    Throwable throwable = thrown;

    // close closeables in LIFO order
    while (!stack.isEmpty()) {
      Closeable closeable = stack.removeFirst();
      try {
        closeable.close();
      } catch (Throwable e) {
        if (throwable == null) {

	// This applies only to the innermost frame at an async safe-point.
	conservative bool

	// buf contains the set of possible pointers to stack objects.
	// Organized as a LIFO linked list of buffers.
	// All buffers except possibly the head buffer are full.
	buf     *stackWorkBuf
	freeBuf *stackWorkBuf // keep around one free buffer for allocation hysteresis

      ArrayList<LockGraphNode> acquiredLockList = requireNonNull(acquiredLocks.get());
      LockGraphNode node = lock.getLockGraphNode();
      // Iterate in reverse because locks are usually locked/unlocked in a
      // LIFO order.
      for (int i = acquiredLockList.size() - 1; i >= 0; i--) {
        if (acquiredLockList.get(i) == node) {
          acquiredLockList.remove(i);
          break;
        }
      }
    }
  }

      ArrayList<LockGraphNode> acquiredLockList = requireNonNull(acquiredLocks.get());
      LockGraphNode node = lock.getLockGraphNode();
      // Iterate in reverse because locks are usually locked/unlocked in a
      // LIFO order.
      for (int i = acquiredLockList.size() - 1; i >= 0; i--) {
        if (acquiredLockList.get(i) == node) {
          acquiredLockList.remove(i);
          break;
        }
      }
    }
  }