func (w traceWriter) writeGoStatus(goid uint64, mid int64, status traceGoStatus, markAssist bool, stackID uint64) traceWriter {
	// The status should never be bad. Some invariant must have been violated.
	if status == traceGoBad {
		print("runtime: goid=", goid, "\n")
		throw("attempted to trace a bad status for a goroutine")
	}

	// Trace the status.
	if stackID == 0 {
		w = w.event(traceEvGoStatus, traceArg(goid), traceArg(uint64(mid)), traceArg(status))

		},
	}
	e.base.args[0] = uint64(s.stack)
	return e
}

// stack represents a goroutine stack sample.
type stack struct {
	pcs []uint64
}

func (s stack) String() string {
	var sb strings.Builder
	for _, frame := range s.pcs {
		fmt.Fprintf(&sb, "\t%#v\n", frame)
	}
	return sb.String()
}

// frame represents a single stack frame.
type frame struct {
	pc     uint64

		if keep {
			filtered.Events = append(filtered.Events, e)
		}
	}
	return
}

func stackFrames(data *format.Data, stackID int) (frames []string) {
	for {
		frame, ok := data.Frames[strconv.Itoa(stackID)]
		if !ok {
			return
		}
		frames = append(frames, frame.Name)
		stackID = frame.Parent
	}
}

func checkProcStartStop(t *testing.T, data format.Data) {
	procStarted := map[uint64]bool{}

		var flushed bool
		w, flushed = w.ensure(2 + 5*traceBytesPerNumber /* traceEvCPUSamples + traceEvCPUSample + timestamp + g + m + p + stack ID */)
		if flushed {
			// Annotate the batch as containing strings.
			w.byte(byte(traceEvCPUSamples))
		}

		// Add the stack to the table.
		stackID := trace.stackTab[gen%2].put(pcBuf[:nstk])

		// Write out the CPU sample.
		w.byte(byte(traceEvCPUSample))
		w.varint(timestamp)

static void*
threadentry(void *v)
{
	ThreadStart ts;
	stack_t ss;

	ts = *(ThreadStart*)v;
	free(v);

	// On NetBSD, a new thread inherits the signal stack of the
	// creating thread. That confuses minit, so we remove that
	// signal stack here before calling the regular mstart. It's
	// a bit baroque to remove a signal stack here only to add one
	// in minit, but it's a simple change that keeps NetBSD

				inlined := (j != len(loc.Line)-1)
				stack.Sources = append(stack.Sources, getSrc(line, inlined))
			}
		}

		leaf := stack.Sources[len(stack.Sources)-1]
		s.Sources[leaf].Self += value
		s.Stacks = append(s.Stacks, stack)
	}
}

func (s *StackSet) fillPlaces() {
	for i, stack := range s.Stacks {
		seenSrcs := map[int]bool{}
		for j, src := range stack.Sources {
			if seenSrcs[src] {
				continue

	// morestack on g0 crash.
	if (g->stacklo >= g->stackhi) {
		fatalf("bad stack bounds: lo=%p hi=%p", (void*)(g->stacklo), (void*)(g->stackhi));
	}
}

void
_cgo_sys_thread_start(ThreadStart *ts)
{
	pthread_attr_t attr;
	sigset_t ign, oset;
	pthread_t p;
	void *base;
	size_t size;
	int err;

	sigfillset(&ign);
	pthread_sigmask(SIG_SETMASK, &ign, &oset);

	pthread_attr_init(&attr);

	size_t size;
	int err;

	sigfillset(&ign);
	pthread_sigmask(SIG_SETMASK, &ign, &oset);

	pthread_attr_init(&attr);
	pthread_attr_getstacksize(&attr, &size);
	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
	ts->g->stackhi = size;
	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);

	pthread_sigmask(SIG_SETMASK, &oset, nil);

	if (err != 0) {
		fatalf("pthread_create failed: %s", strerror(err));

	size_t size;
	int err;

	sigfillset(&ign);
	pthread_sigmask(SIG_SETMASK, &ign, &oset);

	pthread_attr_init(&attr);
	pthread_attr_getstacksize(&attr, &size);
	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
	ts->g->stackhi = size;
	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);

	pthread_sigmask(SIG_SETMASK, &oset, nil);

	if (err != 0) {
		fatalf("pthread_create failed: %s", strerror(err));

	size_t size;
	int err;

	SIGFILLSET(ign);
	pthread_sigmask(SIG_SETMASK, &ign, &oset);

	pthread_attr_init(&attr);
	pthread_attr_getstacksize(&attr, &size);

	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
	ts->g->stackhi = size;
	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);

	pthread_sigmask(SIG_SETMASK, &oset, nil);

	if (err != 0) {
		fatalf("pthread_create failed: %s", strerror(err));