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// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package atomic_test
import (
"runtime"
"runtime/internal/atomic"
"runtime/internal/sys"
"testing"
"unsafe"
)
func runParallel(N, iter int, f func()) {
defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(int(N)))
done := make(chan bool)
for i := 0; i < N; i++ {
go func() {
for j := 0; j < iter; j++ {
f()
}
done <- true
}()
}
for i := 0; i < N; i++ {
<-done
}
}
func TestXadduintptr(t *testing.T) {
N := 20
iter := 100000
if testing.Short() {
N = 10
iter = 10000
}
inc := uintptr(100)
total := uintptr(0)
runParallel(N, iter, func() {
atomic.Xadduintptr(&total, inc)
})
if want := uintptr(N*iter) * inc; want != total {
t.Fatalf("xadduintpr error, want %d, got %d", want, total)
}
total = 0
runParallel(N, iter, func() {
atomic.Xadduintptr(&total, inc)
atomic.Xadduintptr(&total, uintptr(-int64(inc)))
})
if total != 0 {
t.Fatalf("xadduintpr total error, want %d, got %d", 0, total)
}
}
// Tests that xadduintptr correctly updates 64-bit values. The place where
// we actually do so is mstats.go, functions mSysStat{Inc,Dec}.
func TestXadduintptrOnUint64(t *testing.T) {
if sys.BigEndian {
// On big endian architectures, we never use xadduintptr to update
// 64-bit values and hence we skip the test. (Note that functions
// mSysStat{Inc,Dec} in mstats.go have explicit checks for
// big-endianness.)
t.Skip("skip xadduintptr on big endian architecture")
}
const inc = 100
val := uint64(0)
atomic.Xadduintptr((*uintptr)(unsafe.Pointer(&val)), inc)
if inc != val {
t.Fatalf("xadduintptr should increase lower-order bits, want %d, got %d", inc, val)
}
}
func shouldPanic(t *testing.T, name string, f func()) {
defer func() {
if recover() == nil {
t.Errorf("%s did not panic", name)
}
}()
f()
}
// Variant of sync/atomic's TestUnaligned64:
func TestUnaligned64(t *testing.T) {
// Unaligned 64-bit atomics on 32-bit systems are
// a continual source of pain. Test that on 32-bit systems they crash
// instead of failing silently.
switch runtime.GOARCH {
default:
if unsafe.Sizeof(int(0)) != 4 {
t.Skip("test only runs on 32-bit systems")
}
case "amd64p32":
// amd64p32 can handle unaligned atomics.
t.Skipf("test not needed on %v", runtime.GOARCH)
}
x := make([]uint32, 4)
u := unsafe.Pointer(uintptr(unsafe.Pointer(&x[0])) | 4) // force alignment to 4
up64 := (*uint64)(u) // misaligned
p64 := (*int64)(u) // misaligned
shouldPanic(t, "Load64", func() { atomic.Load64(up64) })
shouldPanic(t, "Loadint64", func() { atomic.Loadint64(p64) })
shouldPanic(t, "Store64", func() { atomic.Store64(up64, 0) })
shouldPanic(t, "Xadd64", func() { atomic.Xadd64(up64, 1) })
shouldPanic(t, "Xchg64", func() { atomic.Xchg64(up64, 1) })
shouldPanic(t, "Cas64", func() { atomic.Cas64(up64, 1, 2) })
}
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