runtime: fix finalizer test on amd64

Not scanning the stack by frames means we are reintroducing
a few false positives into the collection. Run the finalizer registration
in its own goroutine so that stack is guaranteed to be out of
consideration in a later collection.

This is working around a regression from yesterday's tip, but
it's not a regression from Go 1.1.

R=golang-dev
TBR=golang-dev
CC=golang-dev
https://golang.org/cl/14290043

diff --git a/src/pkg/runtime/mfinal_test.go b/src/pkg/runtime/mfinal_test.go
index ae06dd291ab97548ba0c8d9a8da4770008aef787..6efef9bb0340e64aca04e6083d07c670cb95d2db 100644 (file)
--- a/src/pkg/runtime/mfinal_test.go
+++ b/src/pkg/runtime/mfinal_test.go
@@ -46,17 +46,18 @@ func TestFinalizerType(t *testing.T) {
        }
 
        for _, tt := range finalizerTests {
-               func() {
+               go func() {
                        v := new(int)
                        *v = 97531
                        runtime.SetFinalizer(tt.convert(v), tt.finalizer)
                        v = nil
                }()
+               time.Sleep(1 * time.Second)
                runtime.GC()
                select {
                case <-ch:
                case <-time.After(time.Second * 4):
-                       t.Errorf("Finalizer of type %T didn't run", tt.finalizer)
+                       t.Errorf("finalizer for type %T didn't run", tt.finalizer)
                }
        }
 }
@@ -72,25 +73,27 @@ func TestFinalizerInterfaceBig(t *testing.T) {
                t.Skipf("Skipping on non-amd64 machine")
        }
        ch := make(chan bool)
-       func() {
+       go func() {
                v := &bigValue{0xDEADBEEFDEADBEEF, true, "It matters not how strait the gate"}
+               old := *v
                runtime.SetFinalizer(v, func(v interface{}) {
                        i, ok := v.(*bigValue)
                        if !ok {
-                               t.Errorf("Expected *bigValue from interface{} in finalizer, got %v", *i)
+                               t.Errorf("finalizer called with type %T, want *bigValue", v)
                        }
-                       if i.fill != 0xDEADBEEFDEADBEEF && i.it != true && i.up != "It matters not how strait the gate" {
-                               t.Errorf("*bigValue from interface{} has the wrong value: %v\n", *i)
+                       if *i != old {
+                               t.Errorf("finalizer called with %+v, want %+v", *i, old)
                        }
                        close(ch)
                })
                v = nil
        }()
+       time.Sleep(1 * time.Second)
        runtime.GC()
        select {
        case <-ch:
-       case <-time.After(time.Second * 4):
-               t.Errorf("Finalizer set by SetFinalizer(*bigValue, func(interface{})) didn't run")
+       case <-time.After(4 * time.Second):
+               t.Errorf("finalizer for type *bigValue didn't run")
        }
 }