gc: treat uintptr as potentially containing a pointer

Fixes #2376

R=golang-dev, lvd, rsc
CC=golang-dev
https://golang.org/cl/5278048

src/cmd/gc/reflect.c

@@ -516,7 +516,6 @@ haspointers(Type *t)
 	case TUINT32:
 	case TINT64:
 	case TUINT64:
-	case TUINTPTR:
 	case TFLOAT32:
 	case TFLOAT64:
 	case TBOOL:
@@ -534,6 +533,7 @@ haspointers(Type *t)
 	case TPTR32:
 	case TPTR64:
 	case TUNSAFEPTR:
+	case TUINTPTR:
 	case TINTER:
 	case TCHAN:
 	case TMAP:

src/pkg/runtime/gc_test.go

@@ -3,6 +3,7 @@ package runtime_test
 import (
 	"runtime"
 	"testing"
+	"unsafe"
 )
 
 func TestGcSys(t *testing.T) {
@@ -22,3 +23,73 @@ func TestGcSys(t *testing.T) {
 func workthegc() []byte {
 	return make([]byte, 1029)
 }
+
+func TestGcUintptr(t *testing.T) {
+	p1 := unsafe.Pointer(new(int))
+	*(*int)(unsafe.Pointer(p1)) = 42
+	p2 := uintptr(unsafe.Pointer(new(int)))
+	*(*int)(unsafe.Pointer(p2)) = 42
+	var a1 [1]unsafe.Pointer
+	a1[0] = unsafe.Pointer(new(int))
+	*(*int)(unsafe.Pointer(a1[0])) = 42
+	var a2 [1]uintptr
+	a2[0] = uintptr(unsafe.Pointer(new(int)))
+	*(*int)(unsafe.Pointer(a2[0])) = 42
+	s1 := make([]unsafe.Pointer, 1)
+	s1[0] = unsafe.Pointer(new(int))
+	*(*int)(unsafe.Pointer(s1[0])) = 42
+	s2 := make([]uintptr, 1)
+	s2[0] = uintptr(unsafe.Pointer(new(int)))
+	*(*int)(unsafe.Pointer(s2[0])) = 42
+	m1 := make(map[int]unsafe.Pointer)
+	m1[0] = unsafe.Pointer(new(int))
+	*(*int)(unsafe.Pointer(m1[0])) = 42
+	m2 := make(map[int]uintptr)
+	m2[0] = uintptr(unsafe.Pointer(new(int)))
+	*(*int)(unsafe.Pointer(m2[0])) = 42
+	c1 := make(chan unsafe.Pointer, 1)
+	func() {
+		p := new(int)
+		*p = 42
+		c1 <- unsafe.Pointer(p)
+	}()
+	c2 := make(chan uintptr, 1)
+	func() {
+		p := new(int)
+		*p = 42
+		c2 <- uintptr(unsafe.Pointer(p))
+	}()
+
+	runtime.GC()
+
+	if p, _ := runtime.Lookup((*byte)(unsafe.Pointer(p1))); p == nil || *(*int)(unsafe.Pointer(p)) != 42 {
+		t.Fatalf("p1 is freed")
+	}
+	if p, _ := runtime.Lookup((*byte)(unsafe.Pointer(p2))); p == nil || *(*int)(unsafe.Pointer(p)) != 42 {
+		t.Fatalf("p2 is freed")
+	}
+	if p, _ := runtime.Lookup((*byte)(unsafe.Pointer(a1[0]))); p == nil || *(*int)(unsafe.Pointer(p)) != 42 {
+		t.Fatalf("a1[0] is freed")
+	}
+	if p, _ := runtime.Lookup((*byte)(unsafe.Pointer(a2[0]))); p == nil || *(*int)(unsafe.Pointer(p)) != 42 {
+		t.Fatalf("a2[0] is freed")
+	}
+	if p, _ := runtime.Lookup((*byte)(unsafe.Pointer(s1[0]))); p == nil || *(*int)(unsafe.Pointer(p)) != 42 {
+		t.Fatalf("s1[0] is freed")
+	}
+	if p, _ := runtime.Lookup((*byte)(unsafe.Pointer(s2[0]))); p == nil || *(*int)(unsafe.Pointer(p)) != 42 {
+		t.Fatalf("s2[0] is freed")
+	}
+	if p, _ := runtime.Lookup((*byte)(unsafe.Pointer(m1[0]))); p == nil || *(*int)(unsafe.Pointer(p)) != 42 {
+		t.Fatalf("m1[0] is freed")
+	}
+	if p, _ := runtime.Lookup((*byte)(unsafe.Pointer(m2[0]))); p == nil || *(*int)(unsafe.Pointer(p)) != 42 {
+		t.Fatalf("m2[0] is freed")
+	}
+	if p, _ := runtime.Lookup((*byte)(unsafe.Pointer(<-c1))); p == nil || *(*int)(unsafe.Pointer(p)) != 42 {
+		t.Fatalf("<-c1 is freed")
+	}
+	if p, _ := runtime.Lookup((*byte)(unsafe.Pointer(<-c2))); p == nil || *(*int)(unsafe.Pointer(p)) != 42 {
+		t.Fatalf("<-c2 is freed")
+	}
+}