Initial commit: Go 1.23 release state

src/runtime/runtime_test.go

@@ -0,0 +1,541 @@
+// Copyright 2012 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 runtime_test
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	. "runtime"
+	"runtime/debug"
+	"slices"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+	"unsafe"
+)
+
+// flagQuick is set by the -quick option to skip some relatively slow tests.
+// This is used by the cmd/dist test runtime:cpu124.
+// The cmd/dist test passes both -test.short and -quick;
+// there are tests that only check testing.Short, and those tests will
+// not be skipped if only -quick is used.
+var flagQuick = flag.Bool("quick", false, "skip slow tests, for cmd/dist test runtime:cpu124")
+
+func init() {
+	// We're testing the runtime, so make tracebacks show things
+	// in the runtime. This only raises the level, so it won't
+	// override GOTRACEBACK=crash from the user.
+	SetTracebackEnv("system")
+}
+
+var errf error
+
+func errfn() error {
+	return errf
+}
+
+func errfn1() error {
+	return io.EOF
+}
+
+func BenchmarkIfaceCmp100(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for j := 0; j < 100; j++ {
+			if errfn() == io.EOF {
+				b.Fatal("bad comparison")
+			}
+		}
+	}
+}
+
+func BenchmarkIfaceCmpNil100(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for j := 0; j < 100; j++ {
+			if errfn1() == nil {
+				b.Fatal("bad comparison")
+			}
+		}
+	}
+}
+
+var efaceCmp1 any
+var efaceCmp2 any
+
+func BenchmarkEfaceCmpDiff(b *testing.B) {
+	x := 5
+	efaceCmp1 = &x
+	y := 6
+	efaceCmp2 = &y
+	for i := 0; i < b.N; i++ {
+		for j := 0; j < 100; j++ {
+			if efaceCmp1 == efaceCmp2 {
+				b.Fatal("bad comparison")
+			}
+		}
+	}
+}
+
+func BenchmarkEfaceCmpDiffIndirect(b *testing.B) {
+	efaceCmp1 = [2]int{1, 2}
+	efaceCmp2 = [2]int{1, 2}
+	for i := 0; i < b.N; i++ {
+		for j := 0; j < 100; j++ {
+			if efaceCmp1 != efaceCmp2 {
+				b.Fatal("bad comparison")
+			}
+		}
+	}
+}
+
+func BenchmarkDefer(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		defer1()
+	}
+}
+
+func defer1() {
+	defer func(x, y, z int) {
+		if recover() != nil || x != 1 || y != 2 || z != 3 {
+			panic("bad recover")
+		}
+	}(1, 2, 3)
+}
+
+func BenchmarkDefer10(b *testing.B) {
+	for i := 0; i < b.N/10; i++ {
+		defer2()
+	}
+}
+
+func defer2() {
+	for i := 0; i < 10; i++ {
+		defer func(x, y, z int) {
+			if recover() != nil || x != 1 || y != 2 || z != 3 {
+				panic("bad recover")
+			}
+		}(1, 2, 3)
+	}
+}
+
+func BenchmarkDeferMany(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		defer func(x, y, z int) {
+			if recover() != nil || x != 1 || y != 2 || z != 3 {
+				panic("bad recover")
+			}
+		}(1, 2, 3)
+	}
+}
+
+func BenchmarkPanicRecover(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		defer3()
+	}
+}
+
+func defer3() {
+	defer func(x, y, z int) {
+		if recover() == nil {
+			panic("failed recover")
+		}
+	}(1, 2, 3)
+	panic("hi")
+}
+
+// golang.org/issue/7063
+func TestStopCPUProfilingWithProfilerOff(t *testing.T) {
+	SetCPUProfileRate(0)
+}
+
+// Addresses to test for faulting behavior.
+// This is less a test of SetPanicOnFault and more a check that
+// the operating system and the runtime can process these faults
+// correctly. That is, we're indirectly testing that without SetPanicOnFault
+// these would manage to turn into ordinary crashes.
+// Note that these are truncated on 32-bit systems, so the bottom 32 bits
+// of the larger addresses must themselves be invalid addresses.
+// We might get unlucky and the OS might have mapped one of these
+// addresses, but probably not: they're all in the first page, very high
+// addresses that normally an OS would reserve for itself, or malformed
+// addresses. Even so, we might have to remove one or two on different
+// systems. We will see.
+
+var faultAddrs = []uint64{
+	// low addresses
+	0,
+	1,
+	0xfff,
+	// high (kernel) addresses
+	// or else malformed.
+	0xffffffffffffffff,
+	0xfffffffffffff001,
+	0xffffffffffff0001,
+	0xfffffffffff00001,
+	0xffffffffff000001,
+	0xfffffffff0000001,
+	0xffffffff00000001,
+	0xfffffff000000001,
+	0xffffff0000000001,
+	0xfffff00000000001,
+	0xffff000000000001,
+	0xfff0000000000001,
+	0xff00000000000001,
+	0xf000000000000001,
+	0x8000000000000001,
+}
+
+func TestSetPanicOnFault(t *testing.T) {
+	old := debug.SetPanicOnFault(true)
+	defer debug.SetPanicOnFault(old)
+
+	nfault := 0
+	for _, addr := range faultAddrs {
+		testSetPanicOnFault(t, uintptr(addr), &nfault)
+	}
+	if nfault == 0 {
+		t.Fatalf("none of the addresses faulted")
+	}
+}
+
+// testSetPanicOnFault tests one potentially faulting address.
+// It deliberately constructs and uses an invalid pointer,
+// so mark it as nocheckptr.
+//
+//go:nocheckptr
+func testSetPanicOnFault(t *testing.T, addr uintptr, nfault *int) {
+	if GOOS == "js" || GOOS == "wasip1" {
+		t.Skip(GOOS + " does not support catching faults")
+	}
+
+	defer func() {
+		if err := recover(); err != nil {
+			*nfault++
+		}
+	}()
+
+	// The read should fault, except that sometimes we hit
+	// addresses that have had C or kernel pages mapped there
+	// readable by user code. So just log the content.
+	// If no addresses fault, we'll fail the test.
+	v := *(*byte)(unsafe.Pointer(addr))
+	t.Logf("addr %#x: %#x\n", addr, v)
+}
+
+func eqstring_generic(s1, s2 string) bool {
+	if len(s1) != len(s2) {
+		return false
+	}
+	// optimization in assembly versions:
+	// if s1.str == s2.str { return true }
+	for i := 0; i < len(s1); i++ {
+		if s1[i] != s2[i] {
+			return false
+		}
+	}
+	return true
+}
+
+func TestEqString(t *testing.T) {
+	// This isn't really an exhaustive test of == on strings, it's
+	// just a convenient way of documenting (via eqstring_generic)
+	// what == does.
+	s := []string{
+		"",
+		"a",
+		"c",
+		"aaa",
+		"ccc",
+		"cccc"[:3], // same contents, different string
+		"1234567890",
+	}
+	for _, s1 := range s {
+		for _, s2 := range s {
+			x := s1 == s2
+			y := eqstring_generic(s1, s2)
+			if x != y {
+				t.Errorf(`("%s" == "%s") = %t, want %t`, s1, s2, x, y)
+			}
+		}
+	}
+}
+
+func TestTrailingZero(t *testing.T) {
+	// make sure we add padding for structs with trailing zero-sized fields
+	type T1 struct {
+		n int32
+		z [0]byte
+	}
+	if unsafe.Sizeof(T1{}) != 8 {
+		t.Errorf("sizeof(%#v)==%d, want 8", T1{}, unsafe.Sizeof(T1{}))
+	}
+	type T2 struct {
+		n int64
+		z struct{}
+	}
+	if unsafe.Sizeof(T2{}) != 8+unsafe.Sizeof(uintptr(0)) {
+		t.Errorf("sizeof(%#v)==%d, want %d", T2{}, unsafe.Sizeof(T2{}), 8+unsafe.Sizeof(uintptr(0)))
+	}
+	type T3 struct {
+		n byte
+		z [4]struct{}
+	}
+	if unsafe.Sizeof(T3{}) != 2 {
+		t.Errorf("sizeof(%#v)==%d, want 2", T3{}, unsafe.Sizeof(T3{}))
+	}
+	// make sure padding can double for both zerosize and alignment
+	type T4 struct {
+		a int32
+		b int16
+		c int8
+		z struct{}
+	}
+	if unsafe.Sizeof(T4{}) != 8 {
+		t.Errorf("sizeof(%#v)==%d, want 8", T4{}, unsafe.Sizeof(T4{}))
+	}
+	// make sure we don't pad a zero-sized thing
+	type T5 struct {
+	}
+	if unsafe.Sizeof(T5{}) != 0 {
+		t.Errorf("sizeof(%#v)==%d, want 0", T5{}, unsafe.Sizeof(T5{}))
+	}
+}
+
+func TestAppendGrowth(t *testing.T) {
+	var x []int64
+	check := func(want int) {
+		if cap(x) != want {
+			t.Errorf("len=%d, cap=%d, want cap=%d", len(x), cap(x), want)
+		}
+	}
+
+	check(0)
+	want := 1
+	for i := 1; i <= 100; i++ {
+		x = append(x, 1)
+		check(want)
+		if i&(i-1) == 0 {
+			want = 2 * i
+		}
+	}
+}
+
+var One = []int64{1}
+
+func TestAppendSliceGrowth(t *testing.T) {
+	var x []int64
+	check := func(want int) {
+		if cap(x) != want {
+			t.Errorf("len=%d, cap=%d, want cap=%d", len(x), cap(x), want)
+		}
+	}
+
+	check(0)
+	want := 1
+	for i := 1; i <= 100; i++ {
+		x = append(x, One...)
+		check(want)
+		if i&(i-1) == 0 {
+			want = 2 * i
+		}
+	}
+}
+
+func TestGoroutineProfileTrivial(t *testing.T) {
+	// Calling GoroutineProfile twice in a row should find the same number of goroutines,
+	// but it's possible there are goroutines just about to exit, so we might end up
+	// with fewer in the second call. Try a few times; it should converge once those
+	// zombies are gone.
+	for i := 0; ; i++ {
+		n1, ok := GoroutineProfile(nil) // should fail, there's at least 1 goroutine
+		if n1 < 1 || ok {
+			t.Fatalf("GoroutineProfile(nil) = %d, %v, want >0, false", n1, ok)
+		}
+		n2, ok := GoroutineProfile(make([]StackRecord, n1))
+		if n2 == n1 && ok {
+			break
+		}
+		t.Logf("GoroutineProfile(%d) = %d, %v, want %d, true", n1, n2, ok, n1)
+		if i >= 10 {
+			t.Fatalf("GoroutineProfile not converging")
+		}
+	}
+}
+
+func BenchmarkGoroutineProfile(b *testing.B) {
+	run := func(fn func() bool) func(b *testing.B) {
+		runOne := func(b *testing.B) {
+			latencies := make([]time.Duration, 0, b.N)
+
+			b.ResetTimer()
+			for i := 0; i < b.N; i++ {
+				start := time.Now()
+				ok := fn()
+				if !ok {
+					b.Fatal("goroutine profile failed")
+				}
+				latencies = append(latencies, time.Since(start))
+			}
+			b.StopTimer()
+
+			// Sort latencies then report percentiles.
+			slices.Sort(latencies)
+			b.ReportMetric(float64(latencies[len(latencies)*50/100]), "p50-ns")
+			b.ReportMetric(float64(latencies[len(latencies)*90/100]), "p90-ns")
+			b.ReportMetric(float64(latencies[len(latencies)*99/100]), "p99-ns")
+		}
+		return func(b *testing.B) {
+			b.Run("idle", runOne)
+
+			b.Run("loaded", func(b *testing.B) {
+				stop := applyGCLoad(b)
+				runOne(b)
+				// Make sure to stop the timer before we wait! The load created above
+				// is very heavy-weight and not easy to stop, so we could end up
+				// confusing the benchmarking framework for small b.N.
+				b.StopTimer()
+				stop()
+			})
+		}
+	}
+
+	// Measure the cost of counting goroutines
+	b.Run("small-nil", run(func() bool {
+		GoroutineProfile(nil)
+		return true
+	}))
+
+	// Measure the cost with a small set of goroutines
+	n := NumGoroutine()
+	p := make([]StackRecord, 2*n+2*GOMAXPROCS(0))
+	b.Run("small", run(func() bool {
+		_, ok := GoroutineProfile(p)
+		return ok
+	}))
+
+	// Measure the cost with a large set of goroutines
+	ch := make(chan int)
+	var ready, done sync.WaitGroup
+	for i := 0; i < 5000; i++ {
+		ready.Add(1)
+		done.Add(1)
+		go func() { ready.Done(); <-ch; done.Done() }()
+	}
+	ready.Wait()
+
+	// Count goroutines with a large allgs list
+	b.Run("large-nil", run(func() bool {
+		GoroutineProfile(nil)
+		return true
+	}))
+
+	n = NumGoroutine()
+	p = make([]StackRecord, 2*n+2*GOMAXPROCS(0))
+	b.Run("large", run(func() bool {
+		_, ok := GoroutineProfile(p)
+		return ok
+	}))
+
+	close(ch)
+	done.Wait()
+
+	// Count goroutines with a large (but unused) allgs list
+	b.Run("sparse-nil", run(func() bool {
+		GoroutineProfile(nil)
+		return true
+	}))
+
+	// Measure the cost of a large (but unused) allgs list
+	n = NumGoroutine()
+	p = make([]StackRecord, 2*n+2*GOMAXPROCS(0))
+	b.Run("sparse", run(func() bool {
+		_, ok := GoroutineProfile(p)
+		return ok
+	}))
+}
+
+func TestVersion(t *testing.T) {
+	// Test that version does not contain \r or \n.
+	vers := Version()
+	if strings.Contains(vers, "\r") || strings.Contains(vers, "\n") {
+		t.Fatalf("cr/nl in version: %q", vers)
+	}
+}
+
+func TestTimediv(t *testing.T) {
+	for _, tc := range []struct {
+		num int64
+		div int32
+		ret int32
+		rem int32
+	}{
+		{
+			num: 8,
+			div: 2,
+			ret: 4,
+			rem: 0,
+		},
+		{
+			num: 9,
+			div: 2,
+			ret: 4,
+			rem: 1,
+		},
+		{
+			// Used by runtime.check.
+			num: 12345*1000000000 + 54321,
+			div: 1000000000,
+			ret: 12345,
+			rem: 54321,
+		},
+		{
+			num: 1<<32 - 1,
+			div: 2,
+			ret: 1<<31 - 1, // no overflow.
+			rem: 1,
+		},
+		{
+			num: 1 << 32,
+			div: 2,
+			ret: 1<<31 - 1, // overflow.
+			rem: 0,
+		},
+		{
+			num: 1 << 40,
+			div: 2,
+			ret: 1<<31 - 1, // overflow.
+			rem: 0,
+		},
+		{
+			num: 1<<40 + 1,
+			div: 1 << 10,
+			ret: 1 << 30,
+			rem: 1,
+		},
+	} {
+		name := fmt.Sprintf("%d div %d", tc.num, tc.div)
+		t.Run(name, func(t *testing.T) {
+			// Double check that the inputs make sense using
+			// standard 64-bit division.
+			ret64 := tc.num / int64(tc.div)
+			rem64 := tc.num % int64(tc.div)
+			if ret64 != int64(int32(ret64)) {
+				// Simulate timediv overflow value.
+				ret64 = 1<<31 - 1
+				rem64 = 0
+			}
+			if ret64 != int64(tc.ret) {
+				t.Errorf("%d / %d got ret %d rem %d want ret %d rem %d", tc.num, tc.div, ret64, rem64, tc.ret, tc.rem)
+			}
+
+			var rem int32
+			ret := Timediv(tc.num, tc.div, &rem)
+			if ret != tc.ret || rem != tc.rem {
+				t.Errorf("timediv %d / %d got ret %d rem %d want ret %d rem %d", tc.num, tc.div, ret, rem, tc.ret, tc.rem)
+			}
+		})
+	}
+}