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sync/atomic: fix TestSwapPointer test

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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>
This commit is contained in:
Keith Randall 2020-04-01 16:34:50 -07:00
parent 2681efaf0e
commit 95773ab9b0
1 changed files with 41 additions and 27 deletions
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68
src/sync/atomic/atomic_test.go
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@ -153,6 +153,21 @@ func TestSwapUintptr(t *testing.T) {
}
}
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 @@ func TestSwapPointer(t *testing.T) {
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 @@ func TestCompareAndSwapPointer(t *testing.T) {
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 @@ func TestLoadPointer(t *testing.T) {
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 @@ func TestStorePointer(t *testing.T) {
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)