sync/atomic: fix TestSwapPointer test
It plays way too loose with unsafe.Pointer rules.
It runs afoul of the checkptr rules, so some race detector builds
were failing.
Fixes #38210
Change-Id: I5e1c78201d06295524fdedb3fe5b49d61446f443
Reviewed-on: https://go-review.googlesource.com/c/go/+/226880
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
diff --git a/src/sync/atomic/atomic_test.go b/src/sync/atomic/atomic_test.go
index 286eadc..83e7c8d 100644
--- a/src/sync/atomic/atomic_test.go
+++ b/src/sync/atomic/atomic_test.go
@@ -153,6 +153,21 @@
}
}
+var global [1024]byte
+
+func testPointers() []unsafe.Pointer {
+ var pointers []unsafe.Pointer
+ // globals
+ for i := 0; i < 10; i++ {
+ pointers = append(pointers, unsafe.Pointer(&global[1<<i-1]))
+ }
+ // heap
+ pointers = append(pointers, unsafe.Pointer(new(byte)))
+ // nil
+ pointers = append(pointers, nil)
+ return pointers
+}
+
func TestSwapPointer(t *testing.T) {
var x struct {
before uintptr
@@ -163,13 +178,14 @@
magicptr := uintptr(m)
x.before = magicptr
x.after = magicptr
- var j uintptr
- for delta := uintptr(1 << 16); delta+delta > delta; delta += delta {
- k := SwapPointer(&x.i, unsafe.Pointer(delta))
- if uintptr(x.i) != delta || uintptr(k) != j {
- t.Fatalf("delta=%d i=%d j=%d k=%d", delta, x.i, j, k)
+ var j unsafe.Pointer
+
+ for _, p := range testPointers() {
+ k := SwapPointer(&x.i, p)
+ if x.i != p || k != j {
+ t.Fatalf("p=%p i=%p j=%p k=%p", p, x.i, j, k)
}
- j = delta
+ j = p
}
if x.before != magicptr || x.after != magicptr {
t.Fatalf("wrong magic: %#x _ %#x != %#x _ %#x", x.before, x.after, magicptr, magicptr)
@@ -456,20 +472,20 @@
magicptr := uintptr(m)
x.before = magicptr
x.after = magicptr
- for val := uintptr(1 << 16); val+val > val; val += val {
- x.i = unsafe.Pointer(val)
- if !CompareAndSwapPointer(&x.i, unsafe.Pointer(val), unsafe.Pointer(val+1)) {
- t.Fatalf("should have swapped %#x %#x", val, val+1)
+ q := unsafe.Pointer(new(byte))
+ for _, p := range testPointers() {
+ x.i = p
+ if !CompareAndSwapPointer(&x.i, p, q) {
+ t.Fatalf("should have swapped %p %p", p, q)
}
- if x.i != unsafe.Pointer(val+1) {
- t.Fatalf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
+ if x.i != q {
+ t.Fatalf("wrong x.i after swap: x.i=%p want %p", x.i, q)
}
- x.i = unsafe.Pointer(val + 1)
- if CompareAndSwapPointer(&x.i, unsafe.Pointer(val), unsafe.Pointer(val+2)) {
- t.Fatalf("should not have swapped %#x %#x", val, val+2)
+ if CompareAndSwapPointer(&x.i, p, nil) {
+ t.Fatalf("should not have swapped %p nil", p)
}
- if x.i != unsafe.Pointer(val+1) {
- t.Fatalf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
+ if x.i != q {
+ t.Fatalf("wrong x.i after swap: x.i=%p want %p", x.i, q)
}
}
if x.before != magicptr || x.after != magicptr {
@@ -595,12 +611,12 @@
magicptr := uintptr(m)
x.before = magicptr
x.after = magicptr
- for delta := uintptr(1 << 16); delta+delta > delta; delta += delta {
+ for _, p := range testPointers() {
+ x.i = p
k := LoadPointer(&x.i)
- if k != x.i {
- t.Fatalf("delta=%d i=%d k=%d", delta, x.i, k)
+ if k != p {
+ t.Fatalf("p=%x k=%x", p, k)
}
- x.i = unsafe.Pointer(uintptr(x.i) + delta)
}
if x.before != magicptr || x.after != magicptr {
t.Fatalf("wrong magic: %#x _ %#x != %#x _ %#x", x.before, x.after, magicptr, magicptr)
@@ -730,13 +746,11 @@
magicptr := uintptr(m)
x.before = magicptr
x.after = magicptr
- v := unsafe.Pointer(uintptr(0))
- for delta := uintptr(1 << 16); delta+delta > delta; delta += delta {
- StorePointer(&x.i, unsafe.Pointer(v))
- if x.i != v {
- t.Fatalf("delta=%d i=%d v=%d", delta, x.i, v)
+ for _, p := range testPointers() {
+ StorePointer(&x.i, p)
+ if x.i != p {
+ t.Fatalf("x.i=%p p=%p", x.i, p)
}
- v = unsafe.Pointer(uintptr(v) + delta)
}
if x.before != magicptr || x.after != magicptr {
t.Fatalf("wrong magic: %#x _ %#x != %#x _ %#x", x.before, x.after, magicptr, magicptr)
