cmd/gc: properly race-instrument for loops

Instrumentation of ntest expression should go to ntest->init.
Same for nincr.
Fixes #5340.

R=golang-dev, daniel.morsing
CC=golang-dev
https://golang.org/cl/10026046

2 files changed, 105 insertions, 0 deletions

diff --git a/src/pkg/runtime/race/testdata/mop_test.go b/src/pkg/runtime/race/testdata/mop_test.go
index d221f444e3..620b7ab6e4 100644
--- a/src/pkg/runtime/race/testdata/mop_test.go
+++ b/src/pkg/runtime/race/testdata/mop_test.go
@@ -306,6 +306,94 @@ func TestRaceRange(t *testing.T) {
 	}
 }
 
+func TestRaceForInit(t *testing.T) {
+	c := make(chan int)
+	x := 0
+	go func() {
+		c <- x
+	}()
+	for x = 42; false; {
+	}
+	<-c
+}
+
+func TestNoRaceForInit(t *testing.T) {
+	done := make(chan bool)
+	c := make(chan bool)
+	x := 0
+	go func() {
+		for {
+			_, ok := <-c
+			if !ok {
+				done <- true
+				return
+			}
+			x++
+		}
+	}()
+	i := 0
+	for x = 42; i < 10; i++ {
+		c <- true
+	}
+	close(c)
+	<-done
+}
+
+func TestRaceForTest(t *testing.T) {
+	done := make(chan bool)
+	c := make(chan bool)
+	stop := false
+	go func() {
+		for {
+			_, ok := <-c
+			if !ok {
+				done <- true
+				return
+			}
+			stop = true
+		}
+	}()
+	for !stop {
+		c <- true
+	}
+	close(c)
+	<-done
+}
+
+func TestRaceForIncr(t *testing.T) {
+	done := make(chan bool)
+	c := make(chan bool)
+	x := 0
+	go func() {
+		for {
+			_, ok := <-c
+			if !ok {
+				done <- true
+				return
+			}
+			x++
+		}
+	}()
+	for i := 0; i < 10; x++ {
+		i++
+		c <- true
+	}
+	close(c)
+	<-done
+}
+
+func TestNoRaceForIncr(t *testing.T) {
+	done := make(chan bool)
+	x := 0
+	go func() {
+		x++
+		done <- true
+	}()
+	for i := 0; i < 0; x++ {
+	}
+	<-done
+}
+
 func TestRacePlus(t *testing.T) {
 	var x, y, z int
 	ch := make(chan int, 2)
diff --git a/src/pkg/runtime/race/testdata/regression_test.go b/src/pkg/runtime/race/testdata/regression_test.go
index 49e03d9082..d461269d98 100644
--- a/src/pkg/runtime/race/testdata/regression_test.go
+++ b/src/pkg/runtime/race/testdata/regression_test.go
@@ -175,3 +175,20 @@ type inltype struct {
 func inlinetest(p **inltype) *inltype {
 	return *p
 }
+
+type iface interface {
+	Foo() *struct{ b bool }
+}
+
+type Int int
+
+func (i Int) Foo() *struct{ b bool } {
+	return &struct{ b bool }{false}
+}
+
+func TestNoRaceForInfiniteLoop(t *testing.T) {
+	var x Int
+	// interface conversion causes nodes to be put on init list
+	for iface(x).Foo().b {
+	}
+}