libgo: Merge to master revision 19184.

The next revision, 19185, renames several runtime files, and
will be handled in a separate change.

From-SVN: r211328

13 files changed, 664 insertions, 192 deletions

diff --git a/libgo/go/runtime/append_test.go b/libgo/go/runtime/append_test.go
index 937c825..a67dc9b 100644
--- a/libgo/go/runtime/append_test.go
+++ b/libgo/go/runtime/append_test.go
@@ -19,6 +19,25 @@ func BenchmarkAppend(b *testing.B) {
 	}
 }
 
+func BenchmarkAppendGrowByte(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		var x []byte
+		for j := 0; j < 1<<20; j++ {
+			x = append(x, byte(j))
+		}
+	}
+}
+
+func BenchmarkAppendGrowString(b *testing.B) {
+	var s string
+	for i := 0; i < b.N; i++ {
+		var x []string
+		for j := 0; j < 1<<20; j++ {
+			x = append(x, s)
+		}
+	}
+}
+
 func benchmarkAppendBytes(b *testing.B, length int) {
 	b.StopTimer()
 	x := make([]byte, 0, N)
diff --git a/libgo/go/runtime/chan_test.go b/libgo/go/runtime/chan_test.go
index eb2c7c6..782176c 100644
--- a/libgo/go/runtime/chan_test.go
+++ b/libgo/go/runtime/chan_test.go
@@ -9,8 +9,327 @@ import (
 	"sync"
 	"sync/atomic"
 	"testing"
+	"time"
 )
 
+func TestChan(t *testing.T) {
+	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(4))
+	N := 200
+	if testing.Short() {
+		N = 20
+	}
+	for chanCap := 0; chanCap < N; chanCap++ {
+		{
+			// Ensure that receive from empty chan blocks.
+			c := make(chan int, chanCap)
+			recv1 := false
+			go func() {
+				_ = <-c
+				recv1 = true
+			}()
+			recv2 := false
+			go func() {
+				_, _ = <-c
+				recv2 = true
+			}()
+			time.Sleep(time.Millisecond)
+			if recv1 || recv2 {
+				t.Fatalf("chan[%d]: receive from empty chan", chanCap)
+			}
+			// Ensure that non-blocking receive does not block.
+			select {
+			case _ = <-c:
+				t.Fatalf("chan[%d]: receive from empty chan", chanCap)
+			default:
+			}
+			select {
+			case _, _ = <-c:
+				t.Fatalf("chan[%d]: receive from empty chan", chanCap)
+			default:
+			}
+			c <- 0
+			c <- 0
+		}
+
+		{
+			// Ensure that send to full chan blocks.
+			c := make(chan int, chanCap)
+			for i := 0; i < chanCap; i++ {
+				c <- i
+			}
+			sent := uint32(0)
+			go func() {
+				c <- 0
+				atomic.StoreUint32(&sent, 1)
+			}()
+			time.Sleep(time.Millisecond)
+			if atomic.LoadUint32(&sent) != 0 {
+				t.Fatalf("chan[%d]: send to full chan", chanCap)
+			}
+			// Ensure that non-blocking send does not block.
+			select {
+			case c <- 0:
+				t.Fatalf("chan[%d]: send to full chan", chanCap)
+			default:
+			}
+			<-c
+		}
+
+		{
+			// Ensure that we receive 0 from closed chan.
+			c := make(chan int, chanCap)
+			for i := 0; i < chanCap; i++ {
+				c <- i
+			}
+			close(c)
+			for i := 0; i < chanCap; i++ {
+				v := <-c
+				if v != i {
+					t.Fatalf("chan[%d]: received %v, expected %v", chanCap, v, i)
+				}
+			}
+			if v := <-c; v != 0 {
+				t.Fatalf("chan[%d]: received %v, expected %v", chanCap, v, 0)
+			}
+			if v, ok := <-c; v != 0 || ok {
+				t.Fatalf("chan[%d]: received %v/%v, expected %v/%v", chanCap, v, ok, 0, false)
+			}
+		}
+
+		{
+			// Ensure that close unblocks receive.
+			c := make(chan int, chanCap)
+			done := make(chan bool)
+			go func() {
+				v, ok := <-c
+				done <- v == 0 && ok == false
+			}()
+			time.Sleep(time.Millisecond)
+			close(c)
+			if !<-done {
+				t.Fatalf("chan[%d]: received non zero from closed chan", chanCap)
+			}
+		}
+
+		{
+			// Send 100 integers,
+			// ensure that we receive them non-corrupted in FIFO order.
+			c := make(chan int, chanCap)
+			go func() {
+				for i := 0; i < 100; i++ {
+					c <- i
+				}
+			}()
+			for i := 0; i < 100; i++ {
+				v := <-c
+				if v != i {
+					t.Fatalf("chan[%d]: received %v, expected %v", chanCap, v, i)
+				}
+			}
+
+			// Same, but using recv2.
+			go func() {
+				for i := 0; i < 100; i++ {
+					c <- i
+				}
+			}()
+			for i := 0; i < 100; i++ {
+				v, ok := <-c
+				if !ok {
+					t.Fatalf("chan[%d]: receive failed, expected %v", chanCap, i)
+				}
+				if v != i {
+					t.Fatalf("chan[%d]: received %v, expected %v", chanCap, v, i)
+				}
+			}
+
+			// Send 1000 integers in 4 goroutines,
+			// ensure that we receive what we send.
+			const P = 4
+			const L = 1000
+			for p := 0; p < P; p++ {
+				go func() {
+					for i := 0; i < L; i++ {
+						c <- i
+					}
+				}()
+			}
+			done := make(chan map[int]int)
+			for p := 0; p < P; p++ {
+				go func() {
+					recv := make(map[int]int)
+					for i := 0; i < L; i++ {
+						v := <-c
+						recv[v] = recv[v] + 1
+					}
+					done <- recv
+				}()
+			}
+			recv := make(map[int]int)
+			for p := 0; p < P; p++ {
+				for k, v := range <-done {
+					recv[k] = recv[k] + v
+				}
+			}
+			if len(recv) != L {
+				t.Fatalf("chan[%d]: received %v values, expected %v", chanCap, len(recv), L)
+			}
+			for _, v := range recv {
+				if v != P {
+					t.Fatalf("chan[%d]: received %v values, expected %v", chanCap, v, P)
+				}
+			}
+		}
+
+		{
+			// Test len/cap.
+			c := make(chan int, chanCap)
+			if len(c) != 0 || cap(c) != chanCap {
+				t.Fatalf("chan[%d]: bad len/cap, expect %v/%v, got %v/%v", chanCap, 0, chanCap, len(c), cap(c))
+			}
+			for i := 0; i < chanCap; i++ {
+				c <- i
+			}
+			if len(c) != chanCap || cap(c) != chanCap {
+				t.Fatalf("chan[%d]: bad len/cap, expect %v/%v, got %v/%v", chanCap, chanCap, chanCap, len(c), cap(c))
+			}
+		}
+
+	}
+}
+
+func TestSelfSelect(t *testing.T) {
+	// Ensure that send/recv on the same chan in select
+	// does not crash nor deadlock.
+	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(2))
+	for _, chanCap := range []int{0, 10} {
+		var wg sync.WaitGroup
+		wg.Add(2)
+		c := make(chan int, chanCap)
+		for p := 0; p < 2; p++ {
+			p := p
+			go func() {
+				defer wg.Done()
+				for i := 0; i < 1000; i++ {
+					if p == 0 || i%2 == 0 {
+						select {
+						case c <- p:
+						case v := <-c:
+							if chanCap == 0 && v == p {
+								t.Fatalf("self receive")
+							}
+						}
+					} else {
+						select {
+						case v := <-c:
+							if chanCap == 0 && v == p {
+								t.Fatalf("self receive")
+							}
+						case c <- p:
+						}
+					}
+				}
+			}()
+		}
+		wg.Wait()
+	}
+}
+
+func TestSelectStress(t *testing.T) {
+	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(10))
+	var c [4]chan int
+	c[0] = make(chan int)
+	c[1] = make(chan int)
+	c[2] = make(chan int, 2)
+	c[3] = make(chan int, 3)
+	N := int(1e5)
+	if testing.Short() {
+		N /= 10
+	}
+	// There are 4 goroutines that send N values on each of the chans,
+	// + 4 goroutines that receive N values on each of the chans,
+	// + 1 goroutine that sends N values on each of the chans in a single select,
+	// + 1 goroutine that receives N values on each of the chans in a single select.
+	// All these sends, receives and selects interact chaotically at runtime,
+	// but we are careful that this whole construct does not deadlock.
+	var wg sync.WaitGroup
+	wg.Add(10)
+	for k := 0; k < 4; k++ {
+		k := k
+		go func() {
+			for i := 0; i < N; i++ {
+				c[k] <- 0
+			}
+			wg.Done()
+		}()
+		go func() {
+			for i := 0; i < N; i++ {
+				<-c[k]
+			}
+			wg.Done()
+		}()
+	}
+	go func() {
+		var n [4]int
+		c1 := c
+		for i := 0; i < 4*N; i++ {
+			select {
+			case c1[3] <- 0:
+				n[3]++
+				if n[3] == N {
+					c1[3] = nil
+				}
+			case c1[2] <- 0:
+				n[2]++
+				if n[2] == N {
+					c1[2] = nil
+				}
+			case c1[0] <- 0:
+				n[0]++
+				if n[0] == N {
+					c1[0] = nil
+				}
+			case c1[1] <- 0:
+				n[1]++
+				if n[1] == N {
+					c1[1] = nil
+				}
+			}
+		}
+		wg.Done()
+	}()
+	go func() {
+		var n [4]int
+		c1 := c
+		for i := 0; i < 4*N; i++ {
+			select {
+			case <-c1[0]:
+				n[0]++
+				if n[0] == N {
+					c1[0] = nil
+				}
+			case <-c1[1]:
+				n[1]++
+				if n[1] == N {
+					c1[1] = nil
+				}
+			case <-c1[2]:
+				n[2]++
+				if n[2] == N {
+					c1[2] = nil
+				}
+			case <-c1[3]:
+				n[3]++
+				if n[3] == N {
+					c1[3] = nil
+				}
+			}
+		}
+		wg.Done()
+	}()
+	wg.Wait()
+}
+
 func TestChanSendInterface(t *testing.T) {
 	type mt struct{}
 	m := &mt{}
@@ -29,34 +348,35 @@ func TestChanSendInterface(t *testing.T) {
 
 func TestPseudoRandomSend(t *testing.T) {
 	n := 100
-	c := make(chan int)
-	l := make([]int, n)
-	var m sync.Mutex
-	m.Lock()
-	go func() {
+	for _, chanCap := range []int{0, n} {
+		c := make(chan int, chanCap)
+		l := make([]int, n)
+		var m sync.Mutex
+		m.Lock()
+		go func() {
+			for i := 0; i < n; i++ {
+				runtime.Gosched()
+				l[i] = <-c
+			}
+			m.Unlock()
+		}()
 		for i := 0; i < n; i++ {
-			runtime.Gosched()
-			l[i] = <-c
+			select {
+			case c <- 1:
+			case c <- 0:
+			}
 		}
-		m.Unlock()
-	}()
-	for i := 0; i < n; i++ {
-		select {
-		case c <- 0:
-		case c <- 1:
+		m.Lock() // wait
+		n0 := 0
+		n1 := 0
+		for _, i := range l {
+			n0 += (i + 1) % 2
+			n1 += i
 		}
-	}
-	m.Lock() // wait
-	n0 := 0
-	n1 := 0
-	for _, i := range l {
-		n0 += (i + 1) % 2
-		n1 += i
-		if n0 > n/10 && n1 > n/10 {
-			return
+		if n0 <= n/10 || n1 <= n/10 {
+			t.Errorf("Want pseudorandom, got %d zeros and %d ones (chan cap %d)", n0, n1, chanCap)
 		}
 	}
-	t.Errorf("Want pseudo random, got %d zeros and %d ones", n0, n1)
 }
 
 func TestMultiConsumer(t *testing.T) {
@@ -110,23 +430,19 @@ func TestMultiConsumer(t *testing.T) {
 	}
 }
 
-func BenchmarkSelectUncontended(b *testing.B) {
+func BenchmarkChanNonblocking(b *testing.B) {
 	const CallsPerSched = 1000
 	procs := runtime.GOMAXPROCS(-1)
 	N := int32(b.N / CallsPerSched)
 	c := make(chan bool, procs)
+	myc := make(chan int)
 	for p := 0; p < procs; p++ {
 		go func() {
-			myc1 := make(chan int, 1)
-			myc2 := make(chan int, 1)
-			myc1 <- 0
 			for atomic.AddInt32(&N, -1) >= 0 {
 				for g := 0; g < CallsPerSched; g++ {
 					select {
-					case <-myc1:
-						myc2 <- 0
-					case <-myc2:
-						myc1 <- 0
+					case <-myc:
+					default:
 					}
 				}
 			}
@@ -138,119 +454,94 @@ func BenchmarkSelectUncontended(b *testing.B) {
 	}
 }
 
+func BenchmarkSelectUncontended(b *testing.B) {
+	b.RunParallel(func(pb *testing.PB) {
+		myc1 := make(chan int, 1)
+		myc2 := make(chan int, 1)
+		myc1 <- 0
+		for pb.Next() {
+			select {
+			case <-myc1:
+				myc2 <- 0
+			case <-myc2:
+				myc1 <- 0
+			}
+		}
+	})
+}
+
 func BenchmarkSelectContended(b *testing.B) {
-	const CallsPerSched = 1000
-	procs := runtime.GOMAXPROCS(-1)
-	N := int32(b.N / CallsPerSched)
-	c := make(chan bool, procs)
+	procs := runtime.GOMAXPROCS(0)
 	myc1 := make(chan int, procs)
 	myc2 := make(chan int, procs)
-	for p := 0; p < procs; p++ {
+	b.RunParallel(func(pb *testing.PB) {
 		myc1 <- 0
-		go func() {
-			for atomic.AddInt32(&N, -1) >= 0 {
-				for g := 0; g < CallsPerSched; g++ {
-					select {
-					case <-myc1:
-						myc2 <- 0
-					case <-myc2:
-						myc1 <- 0
-					}
-				}
+		for pb.Next() {
+			select {
+			case <-myc1:
+				myc2 <- 0
+			case <-myc2:
+				myc1 <- 0
 			}
-			c <- true
-		}()
-	}
-	for p := 0; p < procs; p++ {
-		<-c
-	}
+		}
+	})
 }
 
 func BenchmarkSelectNonblock(b *testing.B) {
-	const CallsPerSched = 1000
-	procs := runtime.GOMAXPROCS(-1)
-	N := int32(b.N / CallsPerSched)
-	c := make(chan bool, procs)
-	for p := 0; p < procs; p++ {
-		go func() {
-			myc1 := make(chan int)
-			myc2 := make(chan int)
-			myc3 := make(chan int, 1)
-			myc4 := make(chan int, 1)
-			for atomic.AddInt32(&N, -1) >= 0 {
-				for g := 0; g < CallsPerSched; g++ {
-					select {
-					case <-myc1:
-					default:
-					}
-					select {
-					case myc2 <- 0:
-					default:
-					}
-					select {
-					case <-myc3:
-					default:
-					}
-					select {
-					case myc4 <- 0:
-					default:
-					}
-				}
+	b.RunParallel(func(pb *testing.PB) {
+		myc1 := make(chan int)
+		myc2 := make(chan int)
+		myc3 := make(chan int, 1)
+		myc4 := make(chan int, 1)
+		for pb.Next() {
+			select {
+			case <-myc1:
+			default:
 			}
-			c <- true
-		}()
-	}
-	for p := 0; p < procs; p++ {
-		<-c
-	}
+			select {
+			case myc2 <- 0:
+			default:
+			}
+			select {
+			case <-myc3:
+			default:
+			}
+			select {
+			case myc4 <- 0:
+			default:
+			}
+		}
+	})
 }
 
 func BenchmarkChanUncontended(b *testing.B) {
-	const CallsPerSched = 1000
-	procs := runtime.GOMAXPROCS(-1)
-	N := int32(b.N / CallsPerSched)
-	c := make(chan bool, procs)
-	for p := 0; p < procs; p++ {
-		go func() {
-			myc := make(chan int, CallsPerSched)
-			for atomic.AddInt32(&N, -1) >= 0 {
-				for g := 0; g < CallsPerSched; g++ {
-					myc <- 0
-				}
-				for g := 0; g < CallsPerSched; g++ {
-					<-myc
-				}
+	const C = 100
+	b.RunParallel(func(pb *testing.PB) {
+		myc := make(chan int, C)
+		for pb.Next() {
+			for i := 0; i < C; i++ {
+				myc <- 0
 			}
-			c <- true
-		}()
-	}
-	for p := 0; p < procs; p++ {
-		<-c
-	}
+			for i := 0; i < C; i++ {
+				<-myc
+			}
+		}
+	})
 }
 
 func BenchmarkChanContended(b *testing.B) {
-	const CallsPerSched = 1000
-	procs := runtime.GOMAXPROCS(-1)
-	N := int32(b.N / CallsPerSched)
-	c := make(chan bool, procs)
-	myc := make(chan int, procs*CallsPerSched)
-	for p := 0; p < procs; p++ {
-		go func() {
-			for atomic.AddInt32(&N, -1) >= 0 {
-				for g := 0; g < CallsPerSched; g++ {
-					myc <- 0
-				}
-				for g := 0; g < CallsPerSched; g++ {
-					<-myc
-				}
+	const C = 100
+	myc := make(chan int, C*runtime.GOMAXPROCS(0))
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			for i := 0; i < C; i++ {
+				myc <- 0
 			}
-			c <- true
-		}()
-	}
-	for p := 0; p < procs; p++ {
-		<-c
-	}
+			for i := 0; i < C; i++ {
+				<-myc
+			}
+		}
+	})
 }
 
 func BenchmarkChanSync(b *testing.B) {
@@ -350,33 +641,95 @@ func BenchmarkChanProdConsWork100(b *testing.B) {
 	benchmarkChanProdCons(b, 100, 100)
 }
 
-func BenchmarkChanCreation(b *testing.B) {
+func BenchmarkSelectProdCons(b *testing.B) {
 	const CallsPerSched = 1000
 	procs := runtime.GOMAXPROCS(-1)
 	N := int32(b.N / CallsPerSched)
-	c := make(chan bool, procs)
+	c := make(chan bool, 2*procs)
+	myc := make(chan int, 128)
+	myclose := make(chan bool)
 	for p := 0; p < procs; p++ {
 		go func() {
+			// Producer: sends to myc.
+			foo := 0
+			// Intended to not fire during benchmarking.
+			mytimer := time.After(time.Hour)
 			for atomic.AddInt32(&N, -1) >= 0 {
 				for g := 0; g < CallsPerSched; g++ {
-					myc := make(chan int, 1)
-					myc <- 0
-					<-myc
+					// Model some local work.
+					for i := 0; i < 100; i++ {
+						foo *= 2
+						foo /= 2
+					}
+					select {
+					case myc <- 1:
+					case <-mytimer:
+					case <-myclose:
+					}
 				}
 			}
-			c <- true
+			myc <- 0
+			c <- foo == 42
+		}()
+		go func() {
+			// Consumer: receives from myc.
+			foo := 0
+			// Intended to not fire during benchmarking.
+			mytimer := time.After(time.Hour)
+		loop:
+			for {
+				select {
+				case v := <-myc:
+					if v == 0 {
+						break loop
+					}
+				case <-mytimer:
+				case <-myclose:
+				}
+				// Model some local work.
+				for i := 0; i < 100; i++ {
+					foo *= 2
+					foo /= 2
+				}
+			}
+			c <- foo == 42
 		}()
 	}
 	for p := 0; p < procs; p++ {
 		<-c
+		<-c
 	}
 }
 
+func BenchmarkChanCreation(b *testing.B) {
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			myc := make(chan int, 1)
+			myc <- 0
+			<-myc
+		}
+	})
+}
+
 func BenchmarkChanSem(b *testing.B) {
 	type Empty struct{}
-	c := make(chan Empty, 1)
-	for i := 0; i < b.N; i++ {
-		c <- Empty{}
+	const CallsPerSched = 1000
+	procs := runtime.GOMAXPROCS(0)
+	N := int32(b.N / CallsPerSched)
+	c := make(chan bool, procs)
+	myc := make(chan Empty, procs)
+	for p := 0; p < procs; p++ {
+		go func() {
+			for atomic.AddInt32(&N, -1) >= 0 {
+				for g := 0; g < CallsPerSched; g++ {
+					myc <- Empty{}
+					<-myc
+				}
+			}
+			c <- true
+		}()
+	}
+	for p := 0; p < procs; p++ {
 		<-c
 	}
 }
diff --git a/libgo/go/runtime/debug/garbage.go b/libgo/go/runtime/debug/garbage.go
index 8337d5d..a724fdf 100644
--- a/libgo/go/runtime/debug/garbage.go
+++ b/libgo/go/runtime/debug/garbage.go
@@ -91,7 +91,9 @@ func (x byDuration) Less(i, j int) bool { return x[i] < x[j] }
 // at startup, or 100 if the variable is not set.
 // A negative percentage disables garbage collection.
 func SetGCPercent(percent int) int {
-	return setGCPercent(percent)
+	old := setGCPercent(percent)
+	runtime.GC()
+	return old
 }
 
 // FreeOSMemory forces a garbage collection followed by an
diff --git a/libgo/go/runtime/debug/stack.go b/libgo/go/runtime/debug/stack.go
index 2896b21..c29b0a2 100644
--- a/libgo/go/runtime/debug/stack.go
+++ b/libgo/go/runtime/debug/stack.go
@@ -18,6 +18,7 @@ var (
 	dunno     = []byte("???")
 	centerDot = []byte("·")
 	dot       = []byte(".")
+	slash     = []byte("/")
 )
 
 // PrintStack prints to standard error the stack trace returned by Stack.
@@ -84,6 +85,11 @@ func function(pc uintptr) []byte {
 	//	runtime/debug.*T·ptrmethod
 	// and want
 	//	*T.ptrmethod
+	// Since the package path might contains dots (e.g. code.google.com/...),
+	// we first remove the path prefix if there is one.
+	if lastslash := bytes.LastIndex(name, slash); lastslash >= 0 {
+		name = name[lastslash+1:]
+	}
 	if period := bytes.Index(name, dot); period >= 0 {
 		name = name[period+1:]
 	}
diff --git a/libgo/go/runtime/error.go b/libgo/go/runtime/error.go
index 88d5df5..d759a54 100644
--- a/libgo/go/runtime/error.go
+++ b/libgo/go/runtime/error.go
@@ -107,19 +107,20 @@ func NewErrorString(s string, ret *interface{}) {
 }
 
 // An errorCString represents a runtime error described by a single C string.
-type errorCString uintptr
+// Not "type errorCString uintptr" because of http://golang.org/issue/7084.
+type errorCString struct{ cstr uintptr }
 
 func (e errorCString) RuntimeError() {}
 
 func cstringToGo(uintptr) string
 
 func (e errorCString) Error() string {
-	return "runtime error: " + cstringToGo(uintptr(e))
+	return "runtime error: " + cstringToGo(e.cstr)
 }
 
 // For calling from C.
 func NewErrorCString(s uintptr, ret *interface{}) {
-	*ret = errorCString(s)
+	*ret = errorCString{s}
 }
 
 type stringer interface {
diff --git a/libgo/go/runtime/export_test.go b/libgo/go/runtime/export_test.go
index 2f678b6..436c28d 100644
--- a/libgo/go/runtime/export_test.go
+++ b/libgo/go/runtime/export_test.go
@@ -82,3 +82,7 @@ var TestSchedLocalQueueSteal1 = testSchedLocalQueueSteal
 
 var hashLoad float64 // declared in hashmap.c
 var HashLoad = &hashLoad
+
+func memclrBytes(b []byte)
+
+var MemclrBytes = memclrBytes
diff --git a/libgo/go/runtime/lfstack_test.go b/libgo/go/runtime/lfstack_test.go
index 505aae6..e518777 100644
--- a/libgo/go/runtime/lfstack_test.go
+++ b/libgo/go/runtime/lfstack_test.go
@@ -71,6 +71,8 @@ func TestLFStack(t *testing.T) {
 	}
 }
 
+var stress []*MyNode
+
 func TestLFStackStress(t *testing.T) {
 	const K = 100
 	P := 4 * GOMAXPROCS(-1)
@@ -80,14 +82,15 @@ func TestLFStackStress(t *testing.T) {
 	}
 	// Create 2 stacks.
 	stacks := [2]*uint64{new(uint64), new(uint64)}
-	// Need to keep additional referenfces to nodes, the stack is not all that type-safe.
-	var nodes []*MyNode
+	// Need to keep additional references to nodes,
+	// the lock-free stack is not type-safe.
+	stress = nil
 	// Push K elements randomly onto the stacks.
 	sum := 0
 	for i := 0; i < K; i++ {
 		sum += i
 		node := &MyNode{data: i}
-		nodes = append(nodes, node)
+		stress = append(stress, node)
 		LFStackPush(stacks[i%2], fromMyNode(node))
 	}
 	c := make(chan bool, P)
@@ -127,4 +130,7 @@ func TestLFStackStress(t *testing.T) {
 	if sum2 != sum {
 		t.Fatalf("Wrong sum %d/%d", sum2, sum)
 	}
+
+	// Let nodes be collected now.
+	stress = nil
 }
diff --git a/libgo/go/runtime/map_test.go b/libgo/go/runtime/map_test.go
index 3d18e3b..fe5d3ad 100644
--- a/libgo/go/runtime/map_test.go
+++ b/libgo/go/runtime/map_test.go
@@ -422,8 +422,7 @@ func TestMapIterOrder(t *testing.T) {
 		t.Skip("skipping for gccgo")
 	}
 
-	// TODO: For issue 6719, add 3 and 7 to this list.
-	for _, n := range [...]int{9, 15} {
+	for _, n := range [...]int{3, 7, 9, 15} {
 		// Make m be {0: true, 1: true, ..., n-1: true}.
 		m := make(map[int]bool)
 		for i := 0; i < n; i++ {
diff --git a/libgo/go/runtime/mem.go b/libgo/go/runtime/mem.go
index ba6d1cf..fb35535 100644
--- a/libgo/go/runtime/mem.go
+++ b/libgo/go/runtime/mem.go
@@ -60,11 +60,10 @@ type MemStats struct {
 
 var Sizeof_C_MStats uintptr // filled in by malloc.goc
 
-var VmemStats MemStats
-
 func init() {
-	if Sizeof_C_MStats != unsafe.Sizeof(VmemStats) {
-		println(Sizeof_C_MStats, unsafe.Sizeof(VmemStats))
+	var memStats MemStats
+	if Sizeof_C_MStats != unsafe.Sizeof(memStats) {
+		println(Sizeof_C_MStats, unsafe.Sizeof(memStats))
 		panic("MStats vs MemStatsType size mismatch")
 	}
 }
diff --git a/libgo/go/runtime/memmove_test.go b/libgo/go/runtime/memmove_test.go
index 9525f06..5c01aac 100644
--- a/libgo/go/runtime/memmove_test.go
+++ b/libgo/go/runtime/memmove_test.go
@@ -5,6 +5,7 @@
 package runtime_test
 
 import (
+	. "runtime"
 	"testing"
 )
 
@@ -80,7 +81,7 @@ func TestMemmoveAlias(t *testing.T) {
 	}
 }
 
-func bmMemmove(n int, b *testing.B) {
+func bmMemmove(b *testing.B, n int) {
 	x := make([]byte, n)
 	y := make([]byte, n)
 	b.SetBytes(int64(n))
@@ -89,28 +90,74 @@ func bmMemmove(n int, b *testing.B) {
 	}
 }
 
-func BenchmarkMemmove0(b *testing.B)    { bmMemmove(0, b) }
-func BenchmarkMemmove1(b *testing.B)    { bmMemmove(1, b) }
-func BenchmarkMemmove2(b *testing.B)    { bmMemmove(2, b) }
-func BenchmarkMemmove3(b *testing.B)    { bmMemmove(3, b) }
-func BenchmarkMemmove4(b *testing.B)    { bmMemmove(4, b) }
-func BenchmarkMemmove5(b *testing.B)    { bmMemmove(5, b) }
-func BenchmarkMemmove6(b *testing.B)    { bmMemmove(6, b) }
-func BenchmarkMemmove7(b *testing.B)    { bmMemmove(7, b) }
-func BenchmarkMemmove8(b *testing.B)    { bmMemmove(8, b) }
-func BenchmarkMemmove9(b *testing.B)    { bmMemmove(9, b) }
-func BenchmarkMemmove10(b *testing.B)   { bmMemmove(10, b) }
-func BenchmarkMemmove11(b *testing.B)   { bmMemmove(11, b) }
-func BenchmarkMemmove12(b *testing.B)   { bmMemmove(12, b) }
-func BenchmarkMemmove13(b *testing.B)   { bmMemmove(13, b) }
-func BenchmarkMemmove14(b *testing.B)   { bmMemmove(14, b) }
-func BenchmarkMemmove15(b *testing.B)   { bmMemmove(15, b) }
-func BenchmarkMemmove16(b *testing.B)   { bmMemmove(16, b) }
-func BenchmarkMemmove32(b *testing.B)   { bmMemmove(32, b) }
-func BenchmarkMemmove64(b *testing.B)   { bmMemmove(64, b) }
-func BenchmarkMemmove128(b *testing.B)  { bmMemmove(128, b) }
-func BenchmarkMemmove256(b *testing.B)  { bmMemmove(256, b) }
-func BenchmarkMemmove512(b *testing.B)  { bmMemmove(512, b) }
-func BenchmarkMemmove1024(b *testing.B) { bmMemmove(1024, b) }
-func BenchmarkMemmove2048(b *testing.B) { bmMemmove(2048, b) }
-func BenchmarkMemmove4096(b *testing.B) { bmMemmove(4096, b) }
+func BenchmarkMemmove0(b *testing.B)    { bmMemmove(b, 0) }
+func BenchmarkMemmove1(b *testing.B)    { bmMemmove(b, 1) }
+func BenchmarkMemmove2(b *testing.B)    { bmMemmove(b, 2) }
+func BenchmarkMemmove3(b *testing.B)    { bmMemmove(b, 3) }
+func BenchmarkMemmove4(b *testing.B)    { bmMemmove(b, 4) }
+func BenchmarkMemmove5(b *testing.B)    { bmMemmove(b, 5) }
+func BenchmarkMemmove6(b *testing.B)    { bmMemmove(b, 6) }
+func BenchmarkMemmove7(b *testing.B)    { bmMemmove(b, 7) }
+func BenchmarkMemmove8(b *testing.B)    { bmMemmove(b, 8) }
+func BenchmarkMemmove9(b *testing.B)    { bmMemmove(b, 9) }
+func BenchmarkMemmove10(b *testing.B)   { bmMemmove(b, 10) }
+func BenchmarkMemmove11(b *testing.B)   { bmMemmove(b, 11) }
+func BenchmarkMemmove12(b *testing.B)   { bmMemmove(b, 12) }
+func BenchmarkMemmove13(b *testing.B)   { bmMemmove(b, 13) }
+func BenchmarkMemmove14(b *testing.B)   { bmMemmove(b, 14) }
+func BenchmarkMemmove15(b *testing.B)   { bmMemmove(b, 15) }
+func BenchmarkMemmove16(b *testing.B)   { bmMemmove(b, 16) }
+func BenchmarkMemmove32(b *testing.B)   { bmMemmove(b, 32) }
+func BenchmarkMemmove64(b *testing.B)   { bmMemmove(b, 64) }
+func BenchmarkMemmove128(b *testing.B)  { bmMemmove(b, 128) }
+func BenchmarkMemmove256(b *testing.B)  { bmMemmove(b, 256) }
+func BenchmarkMemmove512(b *testing.B)  { bmMemmove(b, 512) }
+func BenchmarkMemmove1024(b *testing.B) { bmMemmove(b, 1024) }
+func BenchmarkMemmove2048(b *testing.B) { bmMemmove(b, 2048) }
+func BenchmarkMemmove4096(b *testing.B) { bmMemmove(b, 4096) }
+
+func TestMemclr(t *testing.T) {
+	size := 512
+	if testing.Short() {
+		size = 128 + 16
+	}
+	mem := make([]byte, size)
+	for i := 0; i < size; i++ {
+		mem[i] = 0xee
+	}
+	for n := 0; n < size; n++ {
+		for x := 0; x <= size-n; x++ { // offset in mem
+			MemclrBytes(mem[x : x+n])
+			for i := 0; i < x; i++ {
+				if mem[i] != 0xee {
+					t.Fatalf("overwrite prefix mem[%d] = %d", i, mem[i])
+				}
+			}
+			for i := x; i < x+n; i++ {
+				if mem[i] != 0 {
+					t.Fatalf("failed clear mem[%d] = %d", i, mem[i])
+				}
+				mem[i] = 0xee
+			}
+			for i := x + n; i < size; i++ {
+				if mem[i] != 0xee {
+					t.Fatalf("overwrite suffix mem[%d] = %d", i, mem[i])
+				}
+			}
+		}
+	}
+}
+
+func bmMemclr(b *testing.B, n int) {
+	x := make([]byte, n)
+	b.SetBytes(int64(n))
+	for i := 0; i < b.N; i++ {
+		MemclrBytes(x)
+	}
+}
+func BenchmarkMemclr5(b *testing.B)     { bmMemclr(b, 5) }
+func BenchmarkMemclr16(b *testing.B)    { bmMemclr(b, 16) }
+func BenchmarkMemclr64(b *testing.B)    { bmMemclr(b, 64) }
+func BenchmarkMemclr256(b *testing.B)   { bmMemclr(b, 256) }
+func BenchmarkMemclr4096(b *testing.B)  { bmMemclr(b, 4096) }
+func BenchmarkMemclr65536(b *testing.B) { bmMemclr(b, 65536) }
diff --git a/libgo/go/runtime/pprof/pprof.go b/libgo/go/runtime/pprof/pprof.go
index 3b84285..9808045 100644
--- a/libgo/go/runtime/pprof/pprof.go
+++ b/libgo/go/runtime/pprof/pprof.go
@@ -20,7 +20,7 @@ import (
 	"text/tabwriter"
 )
 
-// BUG(rsc): Profiles are incomplete and inaccuate on NetBSD, OpenBSD, and OS X.
+// BUG(rsc): Profiles are incomplete and inaccuate on NetBSD and OS X.
 // See http://golang.org/issue/6047 for details.
 
 // A Profile is a collection of stack traces showing the call sequences
diff --git a/libgo/go/runtime/pprof/pprof_test.go b/libgo/go/runtime/pprof/pprof_test.go
index e556ca1..923c5b3 100644
--- a/libgo/go/runtime/pprof/pprof_test.go
+++ b/libgo/go/runtime/pprof/pprof_test.go
@@ -33,10 +33,6 @@ func TestCPUProfile(t *testing.T) {
 }
 
 func TestCPUProfileMultithreaded(t *testing.T) {
-	// TODO(brainman): delete when issue 6986 is fixed.
-	if runtime.GOOS == "windows" && runtime.GOARCH == "amd64" {
-		t.Skip("skipping broken test on windows-amd64-race")
-	}
 	buf := make([]byte, 100000)
 	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(2))
 	testCPUProfile(t, []string{"crc32.update"}, func() {
@@ -142,7 +138,11 @@ func testCPUProfile(t *testing.T, need []string, f func()) {
 		t.Logf("no CPU profile samples collected")
 		ok = false
 	}
-	min := total / uintptr(len(have)) / 3
+	// We'd like to check a reasonable minimum, like
+	// total / len(have) / smallconstant, but this test is
+	// pretty flaky (see bug 7095).  So we'll just test to
+	// make sure we got at least one sample.
+	min := uintptr(1)
 	for i, name := range need {
 		if have[i] < min {
 			t.Logf("%s has %d samples out of %d, want at least %d, ideally %d", name, have[i], total, min, total/uintptr(len(have)))
@@ -193,9 +193,6 @@ func TestCPUProfileWithFork(t *testing.T) {
 // If it did, it would see inconsistent state and would either record an incorrect stack
 // or crash because the stack was malformed.
 func TestGoroutineSwitch(t *testing.T) {
-	if runtime.GOOS == "windows" {
-		t.Skip("flaky test; see http://golang.org/issue/6417")
-	}
 	// How much to try. These defaults take about 1 seconds
 	// on a 2012 MacBook Pro. The ones in short mode take
 	// about 0.1 seconds.
@@ -221,7 +218,7 @@ func TestGoroutineSwitch(t *testing.T) {
 			// exists to record a PC without a traceback. Those are okay.
 			if len(stk) == 2 {
 				f := runtime.FuncForPC(stk[1])
-				if f != nil && f.Name() == "System" {
+				if f != nil && (f.Name() == "System" || f.Name() == "ExternalCode") {
 					return
 				}
 			}
@@ -248,10 +245,6 @@ func TestGoroutineSwitch(t *testing.T) {
 
 // Test that profiling of division operations is okay, especially on ARM. See issue 6681.
 func TestMathBigDivide(t *testing.T) {
-	// TODO(brainman): delete when issue 6986 is fixed.
-	if runtime.GOOS == "windows" && runtime.GOARCH == "amd64" {
-		t.Skip("skipping broken test on windows-amd64-race")
-	}
 	testCPUProfile(t, nil, func() {
 		t := time.After(5 * time.Second)
 		pi := new(big.Int)
@@ -272,9 +265,9 @@ func TestMathBigDivide(t *testing.T) {
 
 // Operating systems that are expected to fail the tests. See issue 6047.
 var badOS = map[string]bool{
-	"darwin":  true,
-	"netbsd":  true,
-	"openbsd": true,
+	"darwin": true,
+	"netbsd": true,
+	"plan9":  true,
 }
 
 func TestBlockProfile(t *testing.T) {
diff --git a/libgo/go/runtime/proc_test.go b/libgo/go/runtime/proc_test.go
index 29f71e7..bdcb199 100644
--- a/libgo/go/runtime/proc_test.go
+++ b/libgo/go/runtime/proc_test.go
@@ -246,6 +246,49 @@ func TestPreemptionGC(t *testing.T) {
 	atomic.StoreUint32(&stop, 1)
 }
 
+func TestGCFairness(t *testing.T) {
+	output := executeTest(t, testGCFairnessSource, nil)
+	want := "OK\n"
+	if output != want {
+		t.Fatalf("want %s, got %s\n", want, output)
+	}
+}
+
+const testGCFairnessSource = `
+package main
+
+import (
+	"fmt"
+	"os"
+	"runtime"
+	"time"
+)
+
+func main() {
+	runtime.GOMAXPROCS(1)
+	f, err := os.Open("/dev/null")
+	if os.IsNotExist(err) {
+		// This test tests what it is intended to test only if writes are fast.
+		// If there is no /dev/null, we just don't execute the test.
+		fmt.Println("OK")
+		return
+	}
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+	for i := 0; i < 2; i++ {
+		go func() {
+			for {
+				f.Write([]byte("."))
+			}
+		}()
+	}
+	time.Sleep(10 * time.Millisecond)
+	fmt.Println("OK")
+}
+`
+
 func stackGrowthRecursive(i int) {
 	var pad [128]uint64
 	if i != 0 && pad[0] == 0 {