1 files changed, 386 insertions, 0 deletions
diff --git a/src/runtime/internal/atomic/atomic_test.go b/src/runtime/internal/atomic/atomic_test.go
new file mode 100644
index 0000000..2427bfd
--- /dev/null
+++ b/src/runtime/internal/atomic/atomic_test.go
@@ -0,0 +1,386 @@
+// 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 (
+	"internal/goarch"
+	"runtime"
+	"runtime/internal/atomic"
+	"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 goarch.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() {
+		// Check that all GC maps are sane.
+		runtime.GC()
+
+		err := recover()
+		want := "unaligned 64-bit atomic operation"
+		if err == nil {
+			t.Errorf("%s did not panic", name)
+		} else if s, _ := err.(string); s != want {
+			t.Errorf("%s: wanted panic %q, got %q", name, want, err)
+		}
+	}()
+	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.
+
+	if unsafe.Sizeof(int(0)) != 4 {
+		t.Skip("test only runs on 32-bit systems")
+	}
+
+	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) })
+}
+
+func TestAnd8(t *testing.T) {
+	// Basic sanity check.
+	x := uint8(0xff)
+	for i := uint8(0); i < 8; i++ {
+		atomic.And8(&x, ^(1 << i))
+		if r := uint8(0xff) << (i + 1); x != r {
+			t.Fatalf("clearing bit %#x: want %#x, got %#x", uint8(1<<i), r, x)
+		}
+	}
+
+	// Set every bit in array to 1.
+	a := make([]uint8, 1<<12)
+	for i := range a {
+		a[i] = 0xff
+	}
+
+	// Clear array bit-by-bit in different goroutines.
+	done := make(chan bool)
+	for i := 0; i < 8; i++ {
+		m := ^uint8(1 << i)
+		go func() {
+			for i := range a {
+				atomic.And8(&a[i], m)
+			}
+			done <- true
+		}()
+	}
+	for i := 0; i < 8; i++ {
+		<-done
+	}
+
+	// Check that the array has been totally cleared.
+	for i, v := range a {
+		if v != 0 {
+			t.Fatalf("a[%v] not cleared: want %#x, got %#x", i, uint8(0), v)
+		}
+	}
+}
+
+func TestAnd(t *testing.T) {
+	// Basic sanity check.
+	x := uint32(0xffffffff)
+	for i := uint32(0); i < 32; i++ {
+		atomic.And(&x, ^(1 << i))
+		if r := uint32(0xffffffff) << (i + 1); x != r {
+			t.Fatalf("clearing bit %#x: want %#x, got %#x", uint32(1<<i), r, x)
+		}
+	}
+
+	// Set every bit in array to 1.
+	a := make([]uint32, 1<<12)
+	for i := range a {
+		a[i] = 0xffffffff
+	}
+
+	// Clear array bit-by-bit in different goroutines.
+	done := make(chan bool)
+	for i := 0; i < 32; i++ {
+		m := ^uint32(1 << i)
+		go func() {
+			for i := range a {
+				atomic.And(&a[i], m)
+			}
+			done <- true
+		}()
+	}
+	for i := 0; i < 32; i++ {
+		<-done
+	}
+
+	// Check that the array has been totally cleared.
+	for i, v := range a {
+		if v != 0 {
+			t.Fatalf("a[%v] not cleared: want %#x, got %#x", i, uint32(0), v)
+		}
+	}
+}
+
+func TestOr8(t *testing.T) {
+	// Basic sanity check.
+	x := uint8(0)
+	for i := uint8(0); i < 8; i++ {
+		atomic.Or8(&x, 1<<i)
+		if r := (uint8(1) << (i + 1)) - 1; x != r {
+			t.Fatalf("setting bit %#x: want %#x, got %#x", uint8(1)<<i, r, x)
+		}
+	}
+
+	// Start with every bit in array set to 0.
+	a := make([]uint8, 1<<12)
+
+	// Set every bit in array bit-by-bit in different goroutines.
+	done := make(chan bool)
+	for i := 0; i < 8; i++ {
+		m := uint8(1 << i)
+		go func() {
+			for i := range a {
+				atomic.Or8(&a[i], m)
+			}
+			done <- true
+		}()
+	}
+	for i := 0; i < 8; i++ {
+		<-done
+	}
+
+	// Check that the array has been totally set.
+	for i, v := range a {
+		if v != 0xff {
+			t.Fatalf("a[%v] not fully set: want %#x, got %#x", i, uint8(0xff), v)
+		}
+	}
+}
+
+func TestOr(t *testing.T) {
+	// Basic sanity check.
+	x := uint32(0)
+	for i := uint32(0); i < 32; i++ {
+		atomic.Or(&x, 1<<i)
+		if r := (uint32(1) << (i + 1)) - 1; x != r {
+			t.Fatalf("setting bit %#x: want %#x, got %#x", uint32(1)<<i, r, x)
+		}
+	}
+
+	// Start with every bit in array set to 0.
+	a := make([]uint32, 1<<12)
+
+	// Set every bit in array bit-by-bit in different goroutines.
+	done := make(chan bool)
+	for i := 0; i < 32; i++ {
+		m := uint32(1 << i)
+		go func() {
+			for i := range a {
+				atomic.Or(&a[i], m)
+			}
+			done <- true
+		}()
+	}
+	for i := 0; i < 32; i++ {
+		<-done
+	}
+
+	// Check that the array has been totally set.
+	for i, v := range a {
+		if v != 0xffffffff {
+			t.Fatalf("a[%v] not fully set: want %#x, got %#x", i, uint32(0xffffffff), v)
+		}
+	}
+}
+
+func TestBitwiseContended8(t *testing.T) {
+	// Start with every bit in array set to 0.
+	a := make([]uint8, 16)
+
+	// Iterations to try.
+	N := 1 << 16
+	if testing.Short() {
+		N = 1 << 10
+	}
+
+	// Set and then clear every bit in the array bit-by-bit in different goroutines.
+	done := make(chan bool)
+	for i := 0; i < 8; i++ {
+		m := uint8(1 << i)
+		go func() {
+			for n := 0; n < N; n++ {
+				for i := range a {
+					atomic.Or8(&a[i], m)
+					if atomic.Load8(&a[i])&m != m {
+						t.Errorf("a[%v] bit %#x not set", i, m)
+					}
+					atomic.And8(&a[i], ^m)
+					if atomic.Load8(&a[i])&m != 0 {
+						t.Errorf("a[%v] bit %#x not clear", i, m)
+					}
+				}
+			}
+			done <- true
+		}()
+	}
+	for i := 0; i < 8; i++ {
+		<-done
+	}
+
+	// Check that the array has been totally cleared.
+	for i, v := range a {
+		if v != 0 {
+			t.Fatalf("a[%v] not cleared: want %#x, got %#x", i, uint8(0), v)
+		}
+	}
+}
+
+func TestBitwiseContended(t *testing.T) {
+	// Start with every bit in array set to 0.
+	a := make([]uint32, 16)
+
+	// Iterations to try.
+	N := 1 << 16
+	if testing.Short() {
+		N = 1 << 10
+	}
+
+	// Set and then clear every bit in the array bit-by-bit in different goroutines.
+	done := make(chan bool)
+	for i := 0; i < 32; i++ {
+		m := uint32(1 << i)
+		go func() {
+			for n := 0; n < N; n++ {
+				for i := range a {
+					atomic.Or(&a[i], m)
+					if atomic.Load(&a[i])&m != m {
+						t.Errorf("a[%v] bit %#x not set", i, m)
+					}
+					atomic.And(&a[i], ^m)
+					if atomic.Load(&a[i])&m != 0 {
+						t.Errorf("a[%v] bit %#x not clear", i, m)
+					}
+				}
+			}
+			done <- true
+		}()
+	}
+	for i := 0; i < 32; i++ {
+		<-done
+	}
+
+	// Check that the array has been totally cleared.
+	for i, v := range a {
+		if v != 0 {
+			t.Fatalf("a[%v] not cleared: want %#x, got %#x", i, uint32(0), v)
+		}
+	}
+}
+
+func TestCasRel(t *testing.T) {
+	const _magic = 0x5a5aa5a5
+	var x struct {
+		before uint32
+		i      uint32
+		after  uint32
+		o      uint32
+		n      uint32
+	}
+
+	x.before = _magic
+	x.after = _magic
+	for j := 0; j < 32; j += 1 {
+		x.i = (1 << j) + 0
+		x.o = (1 << j) + 0
+		x.n = (1 << j) + 1
+		if !atomic.CasRel(&x.i, x.o, x.n) {
+			t.Fatalf("should have swapped %#x %#x", x.o, x.n)
+		}
+
+		if x.i != x.n {
+			t.Fatalf("wrong x.i after swap: x.i=%#x x.n=%#x", x.i, x.n)
+		}
+
+		if x.before != _magic || x.after != _magic {
+			t.Fatalf("wrong magic: %#x _ %#x != %#x _ %#x", x.before, x.after, _magic, _magic)
+		}
+	}
+}
+
+func TestStorepNoWB(t *testing.T) {
+	var p [2]*int
+	for i := range p {
+		atomic.StorepNoWB(unsafe.Pointer(&p[i]), unsafe.Pointer(new(int)))
+	}
+	if p[0] == p[1] {
+		t.Error("Bad escape analysis of StorepNoWB")
+	}
+}