cmd/gc: implement more cases in racewalk.

Add missing CLOSUREVAR in switch.
Mark MAKE, string conversion nodes as impossible.
Control statements do not need instrumentation.
Instrument COM and LROT nodes.
Instrument map length.

Update #4228

R=dvyukov, golang-dev
CC=golang-dev
https://golang.org/cl/7504047

4 files changed, 131 insertions, 4 deletions

diff --git a/src/pkg/runtime/race/testdata/map_test.go b/src/pkg/runtime/race/testdata/map_test.go
index 6f86a50b70..35db8db69b 100644
--- a/src/pkg/runtime/race/testdata/map_test.go
+++ b/src/pkg/runtime/race/testdata/map_test.go
@@ -94,8 +94,7 @@ func TestNoRaceMapRangeRange(t *testing.T) {
 	<-ch
 }
 
-// Map len is not instrumented.
-func TestRaceFailingMapLen(t *testing.T) {
+func TestRaceMapLen(t *testing.T) {
 	m := make(map[string]bool)
 	ch := make(chan bool, 1)
 	go func() {
@@ -117,8 +116,7 @@ func TestRaceMapDelete(t *testing.T) {
 	<-ch
 }
 
-// Map len is not instrumented.
-func TestRaceFailingMapLenDelete(t *testing.T) {
+func TestRaceMapLenDelete(t *testing.T) {
 	m := make(map[string]bool)
 	ch := make(chan bool, 1)
 	go func() {
diff --git a/src/pkg/runtime/race/testdata/mop_test.go b/src/pkg/runtime/race/testdata/mop_test.go
index f2daa37301..26cd3a4e41 100644
--- a/src/pkg/runtime/race/testdata/mop_test.go
+++ b/src/pkg/runtime/race/testdata/mop_test.go
@@ -306,6 +306,102 @@ func TestNoRacePlus(t *testing.T) {
 	<-ch
 }
 
+func TestRaceComplement(t *testing.T) {
+	var x, y, z int
+	ch := make(chan int, 2)
+
+	go func() {
+		x = ^y
+		ch <- 1
+	}()
+	go func() {
+		y = ^z
+		ch <- 1
+	}()
+	<-ch
+	<-ch
+}
+
+func TestRaceDiv(t *testing.T) {
+	var x, y, z int
+	ch := make(chan int, 2)
+
+	go func() {
+		x = y / (z + 1)
+		ch <- 1
+	}()
+	go func() {
+		y = z
+		ch <- 1
+	}()
+	<-ch
+	<-ch
+}
+
+func TestRaceDivConst(t *testing.T) {
+	var x, y, z int
+	ch := make(chan int, 2)
+
+	go func() {
+		x = y / 3
+		ch <- 1
+	}()
+	go func() {
+		y = z
+		ch <- 1
+	}()
+	<-ch
+	<-ch
+}
+
+func TestRaceMod(t *testing.T) {
+	var x, y, z int
+	ch := make(chan int, 2)
+
+	go func() {
+		x = y % (z + 1)
+		ch <- 1
+	}()
+	go func() {
+		y = z
+		ch <- 1
+	}()
+	<-ch
+	<-ch
+}
+
+func TestRaceModConst(t *testing.T) {
+	var x, y, z int
+	ch := make(chan int, 2)
+
+	go func() {
+		x = y % 3
+		ch <- 1
+	}()
+	go func() {
+		y = z
+		ch <- 1
+	}()
+	<-ch
+	<-ch
+}
+
+func TestRaceRotate(t *testing.T) {
+	var x, y, z uint32
+	ch := make(chan int, 2)
+
+	go func() {
+		x = y<<12 | y>>20
+		ch <- 1
+	}()
+	go func() {
+		y = z
+		ch <- 1
+	}()
+	<-ch
+	<-ch
+}
+
 // May crash if the instrumentation is reckless.
 func TestNoRaceEnoughRegisters(t *testing.T) {
 	// from erf.go
diff --git a/src/pkg/runtime/race/testdata/regression_test.go b/src/pkg/runtime/race/testdata/regression_test.go
index afe8cc5ec2..f08ee3ed31 100644
--- a/src/pkg/runtime/race/testdata/regression_test.go
+++ b/src/pkg/runtime/race/testdata/regression_test.go
@@ -45,6 +45,18 @@ func InstrumentMapLen3() {
 	_ = len(*m[0])
 }
 
+func TestRaceUnaddressableMapLen(t *testing.T) {
+	m := make(map[int]map[int]int)
+	ch := make(chan int, 1)
+	m[0] = make(map[int]int)
+	go func() {
+		_ = len(m[0])
+		ch <- 0
+	}()
+	m[0][0] = 1
+	<-ch
+}
+
 type Rect struct {
 	x, y int
 }
diff --git a/src/pkg/runtime/race/testdata/slice_test.go b/src/pkg/runtime/race/testdata/slice_test.go
index 773463662b..1fe051b121 100644
--- a/src/pkg/runtime/race/testdata/slice_test.go
+++ b/src/pkg/runtime/race/testdata/slice_test.go
@@ -463,3 +463,24 @@ func TestRaceSliceRuneToString(t *testing.T) {
 	s[9] = 42
 	<-c
 }
+
+func TestRaceConcatString(t *testing.T) {
+	s := "hello"
+	c := make(chan string, 1)
+	go func() {
+		c <- s + " world"
+	}()
+	s = "world"
+	<-c
+}
+
+func TestRaceCompareString(t *testing.T) {
+	s1 := "hello"
+	s2 := "world"
+	c := make(chan bool, 1)
+	go func() {
+		c <- s1 == s2
+	}()
+	s1 = s2
+	<-c
+}