libgo: update to Go1.14beta1

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/214297

3 files changed, 15 insertions, 13 deletions

diff --git a/libgo/go/sync/atomic/atomic_test.go b/libgo/go/sync/atomic/atomic_test.go
index 39c40c6..286eadc 100644
--- a/libgo/go/sync/atomic/atomic_test.go
+++ b/libgo/go/sync/atomic/atomic_test.go
@@ -1140,6 +1140,9 @@ func hammerStoreLoadUintptr(t *testing.T, paddr unsafe.Pointer) {
 	StoreUintptr(addr, new)
 }
 
+//go:nocheckptr
+// This code is just testing that LoadPointer/StorePointer operate
+// atomically; it's not actually calculating pointers.
 func hammerStoreLoadPointer(t *testing.T, paddr unsafe.Pointer) {
 	addr := (*unsafe.Pointer)(paddr)
 	v := uintptr(LoadPointer(addr))
@@ -1391,15 +1394,8 @@ func TestUnaligned64(t *testing.T) {
 	// Unaligned 64-bit atomics on 32-bit systems are
 	// a continual source of pain. Test that on 32-bit systems they crash
 	// instead of failing silently.
-
-	switch runtime.GOARCH {
-	default:
-		if !arch32 {
-			t.Skip("test only runs on 32-bit systems")
-		}
-	case "amd64p32":
-		// amd64p32 can handle unaligned atomics.
-		t.Skipf("test not needed on %v", runtime.GOARCH)
+	if !arch32 {
+		t.Skip("test only runs on 32-bit systems")
 	}
 
 	x := make([]uint32, 4)
diff --git a/libgo/go/sync/mutex.go b/libgo/go/sync/mutex.go
index 11ad20c..3028552 100644
--- a/libgo/go/sync/mutex.go
+++ b/libgo/go/sync/mutex.go
@@ -216,7 +216,8 @@ func (m *Mutex) unlockSlow(new int32) {
 			old = m.state
 		}
 	} else {
-		// Starving mode: handoff mutex ownership to the next waiter.
+		// Starving mode: handoff mutex ownership to the next waiter, and yield
+		// our time slice so that the next waiter can start to run immediately.
 		// Note: mutexLocked is not set, the waiter will set it after wakeup.
 		// But mutex is still considered locked if mutexStarving is set,
 		// so new coming goroutines won't acquire it.
diff --git a/libgo/go/sync/waitgroup_test.go b/libgo/go/sync/waitgroup_test.go
index 4ab438c..c569e0f 100644
--- a/libgo/go/sync/waitgroup_test.go
+++ b/libgo/go/sync/waitgroup_test.go
@@ -147,7 +147,7 @@ func TestWaitGroupMisuse3(t *testing.T) {
 		}
 	}()
 	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(4))
-	done := make(chan interface{}, 2)
+	done := make(chan interface{}, 3)
 	// The detection is opportunistically, so we want it to panic
 	// at least in one run out of a million.
 	for i := 0; i < 1e6; i++ {
@@ -171,8 +171,13 @@ func TestWaitGroupMisuse3(t *testing.T) {
 			}()
 			wg.Wait()
 		}()
-		wg.Wait()
-		for j := 0; j < 2; j++ {
+		go func() {
+			defer func() {
+				done <- recover()
+			}()
+			wg.Wait()
+		}()
+		for j := 0; j < 3; j++ {
 			if err := <-done; err != nil {
 				panic(err)
 			}