1 files changed, 132 insertions, 43 deletions
diff --git a/src/pkg/runtime/mfinal_test.go b/src/pkg/runtime/mfinal_test.go
index 6efef9bb0..6b53888ab 100644
--- a/src/pkg/runtime/mfinal_test.go
+++ b/src/pkg/runtime/mfinal_test.go
@@ -6,10 +6,9 @@ package runtime_test
 
 import (
 	"runtime"
-	"sync"
-	"sync/atomic"
 	"testing"
 	"time"
+	"unsafe"
 )
 
 type Tintptr *int // assignable to *int
@@ -46,13 +45,15 @@ func TestFinalizerType(t *testing.T) {
 	}
 
 	for _, tt := range finalizerTests {
+		done := make(chan bool, 1)
 		go func() {
 			v := new(int)
 			*v = 97531
 			runtime.SetFinalizer(tt.convert(v), tt.finalizer)
 			v = nil
+			done <- true
 		}()
-		time.Sleep(1 * time.Second)
+		<-done
 		runtime.GC()
 		select {
 		case <-ch:
@@ -73,6 +74,7 @@ func TestFinalizerInterfaceBig(t *testing.T) {
 		t.Skipf("Skipping on non-amd64 machine")
 	}
 	ch := make(chan bool)
+	done := make(chan bool, 1)
 	go func() {
 		v := &bigValue{0xDEADBEEFDEADBEEF, true, "It matters not how strait the gate"}
 		old := *v
@@ -87,8 +89,9 @@ func TestFinalizerInterfaceBig(t *testing.T) {
 			close(ch)
 		})
 		v = nil
+		done <- true
 	}()
-	time.Sleep(1 * time.Second)
+	<-done
 	runtime.GC()
 	select {
 	case <-ch:
@@ -100,51 +103,137 @@ func TestFinalizerInterfaceBig(t *testing.T) {
 func fin(v *int) {
 }
 
+// Verify we don't crash at least. golang.org/issue/6857
+func TestFinalizerZeroSizedStruct(t *testing.T) {
+	type Z struct{}
+	z := new(Z)
+	runtime.SetFinalizer(z, func(*Z) {})
+}
+
 func BenchmarkFinalizer(b *testing.B) {
-	const CallsPerSched = 1000
-	procs := runtime.GOMAXPROCS(-1)
-	N := int32(b.N / CallsPerSched)
-	var wg sync.WaitGroup
-	wg.Add(procs)
-	for p := 0; p < procs; p++ {
-		go func() {
-			var data [CallsPerSched]*int
-			for i := 0; i < CallsPerSched; i++ {
-				data[i] = new(int)
+	const Batch = 1000
+	b.RunParallel(func(pb *testing.PB) {
+		var data [Batch]*int
+		for i := 0; i < Batch; i++ {
+			data[i] = new(int)
+		}
+		for pb.Next() {
+			for i := 0; i < Batch; i++ {
+				runtime.SetFinalizer(data[i], fin)
 			}
-			for atomic.AddInt32(&N, -1) >= 0 {
-				runtime.Gosched()
-				for i := 0; i < CallsPerSched; i++ {
-					runtime.SetFinalizer(data[i], fin)
-				}
-				for i := 0; i < CallsPerSched; i++ {
-					runtime.SetFinalizer(data[i], nil)
-				}
+			for i := 0; i < Batch; i++ {
+				runtime.SetFinalizer(data[i], nil)
 			}
-			wg.Done()
-		}()
-	}
-	wg.Wait()
+		}
+	})
 }
 
 func BenchmarkFinalizerRun(b *testing.B) {
-	const CallsPerSched = 1000
-	procs := runtime.GOMAXPROCS(-1)
-	N := int32(b.N / CallsPerSched)
-	var wg sync.WaitGroup
-	wg.Add(procs)
-	for p := 0; p < procs; p++ {
-		go func() {
-			for atomic.AddInt32(&N, -1) >= 0 {
-				runtime.Gosched()
-				for i := 0; i < CallsPerSched; i++ {
-					v := new(int)
-					runtime.SetFinalizer(v, fin)
-				}
-				runtime.GC()
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			v := new(int)
+			runtime.SetFinalizer(v, fin)
+		}
+	})
+}
+
+// One chunk must be exactly one sizeclass in size.
+// It should be a sizeclass not used much by others, so we
+// have a greater chance of finding adjacent ones.
+// size class 19: 320 byte objects, 25 per page, 1 page alloc at a time
+const objsize = 320
+
+type objtype [objsize]byte
+
+func adjChunks() (*objtype, *objtype) {
+	var s []*objtype
+
+	for {
+		c := new(objtype)
+		for _, d := range s {
+			if uintptr(unsafe.Pointer(c))+unsafe.Sizeof(*c) == uintptr(unsafe.Pointer(d)) {
+				return c, d
 			}
-			wg.Done()
-		}()
+			if uintptr(unsafe.Pointer(d))+unsafe.Sizeof(*c) == uintptr(unsafe.Pointer(c)) {
+				return d, c
+			}
+		}
+		s = append(s, c)
+	}
+}
+
+// Make sure an empty slice on the stack doesn't pin the next object in memory.
+func TestEmptySlice(t *testing.T) {
+	if true { // disable until bug 7564 is fixed.
+		return
+	}
+	x, y := adjChunks()
+
+	// the pointer inside xs points to y.
+	xs := x[objsize:] // change objsize to objsize-1 and the test passes
+
+	fin := make(chan bool, 1)
+	runtime.SetFinalizer(y, func(z *objtype) { fin <- true })
+	runtime.GC()
+	select {
+	case <-fin:
+	case <-time.After(4 * time.Second):
+		t.Errorf("finalizer of next object in memory didn't run")
+	}
+	xsglobal = xs // keep empty slice alive until here
+}
+
+var xsglobal []byte
+
+func adjStringChunk() (string, *objtype) {
+	b := make([]byte, objsize)
+	for {
+		s := string(b)
+		t := new(objtype)
+		p := *(*uintptr)(unsafe.Pointer(&s))
+		q := uintptr(unsafe.Pointer(t))
+		if p+objsize == q {
+			return s, t
+		}
+	}
+}
+
+// Make sure an empty string on the stack doesn't pin the next object in memory.
+func TestEmptyString(t *testing.T) {
+	x, y := adjStringChunk()
+
+	ss := x[objsize:] // change objsize to objsize-1 and the test passes
+	fin := make(chan bool, 1)
+	// set finalizer on string contents of y
+	runtime.SetFinalizer(y, func(z *objtype) { fin <- true })
+	runtime.GC()
+	select {
+	case <-fin:
+	case <-time.After(4 * time.Second):
+		t.Errorf("finalizer of next string in memory didn't run")
 	}
-	wg.Wait()
+	ssglobal = ss // keep 0-length string live until here
+}
+
+var ssglobal string
+
+// Test for issue 7656.
+func TestFinalizerOnGlobal(t *testing.T) {
+	runtime.SetFinalizer(Foo1, func(p *Object1) {})
+	runtime.SetFinalizer(Foo2, func(p *Object2) {})
+	runtime.SetFinalizer(Foo1, nil)
+	runtime.SetFinalizer(Foo2, nil)
 }
+
+type Object1 struct {
+	Something []byte
+}
+
+type Object2 struct {
+	Something byte
+}
+
+var (
+	Foo2 = &Object2{}
+	Foo1 = &Object1{}
+)