EvGoSleep           event.Type = 19 // goroutine calls Sleep [timestamp, stack]
	EvGoBlock           event.Type = 20 // goroutine blocks [timestamp, stack]
	EvGoUnblock         event.Type = 21 // goroutine is unblocked [timestamp, goroutine id, seq, stack]
	EvGoBlockSend       event.Type = 22 // goroutine blocks on chan send [timestamp, stack]
	EvGoBlockRecv       event.Type = 23 // goroutine blocks on chan recv [timestamp, stack]

				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);

	// allocation.
	if newsize < fixedStack {
		return
	}
	// Compute how much of the stack is currently in use and only
	// shrink the stack if gp is using less than a quarter of its
	// current stack. The currently used stack includes everything
	// down to the SP plus the stack guard space that ensures
	// there's room for nosplit functions.
	avail := gp.stack.hi - gp.stack.lo

	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));

	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));

	defer trace.Stop() // in case of early return

	// Now we will do a bunch of things for which we verify stacks later.
	// It is impossible to ensure that a goroutine has actually blocked
	// on a channel, in a select or otherwise. So we kick off goroutines
	// that need to block first in the hope that while we are executing
	// the rest of the test, they will block.
	go func() { // func1
		select {}
	}()
	go func() { // func2
		var c chan int