libgo: update to Go1.18beta2

gotools/
	* Makefile.am (go_cmd_cgo_files): Add ast_go118.go
	(check-go-tool): Copy golang.org/x/tools directories.
	* Makefile.in: Regenerate.

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/384695

15 files changed, 195 insertions, 186 deletions

diff --git a/libgo/go/os/exec/exec.go b/libgo/go/os/exec/exec.go
index 0c49575..845b737 100644
--- a/libgo/go/os/exec/exec.go
+++ b/libgo/go/os/exec/exec.go
@@ -216,7 +216,7 @@ func (c *Cmd) String() string {
 
 // interfaceEqual protects against panics from doing equality tests on
 // two interfaces with non-comparable underlying types.
-func interfaceEqual(a, b interface{}) bool {
+func interfaceEqual(a, b any) bool {
 	defer func() {
 		recover()
 	}()
@@ -748,12 +748,11 @@ func dedupEnvCase(caseInsensitive bool, env []string) []string {
 	out := make([]string, 0, len(env))
 	saw := make(map[string]int, len(env)) // key => index into out
 	for _, kv := range env {
-		eq := strings.Index(kv, "=")
-		if eq < 0 {
+		k, _, ok := strings.Cut(kv, "=")
+		if !ok {
 			out = append(out, kv)
 			continue
 		}
-		k := kv[:eq]
 		if caseInsensitive {
 			k = strings.ToLower(k)
 		}
@@ -775,11 +774,10 @@ func addCriticalEnv(env []string) []string {
 		return env
 	}
 	for _, kv := range env {
-		eq := strings.Index(kv, "=")
-		if eq < 0 {
+		k, _, ok := strings.Cut(kv, "=")
+		if !ok {
 			continue
 		}
-		k := kv[:eq]
 		if strings.EqualFold(k, "SYSTEMROOT") {
 			// We already have it.
 			return env
diff --git a/libgo/go/os/exec/exec_linux_test.go b/libgo/go/os/exec/exec_linux_test.go
index 3cfa30e..4a37c96 100644
--- a/libgo/go/os/exec/exec_linux_test.go
+++ b/libgo/go/os/exec/exec_linux_test.go
@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build linux && cgo
-// +build linux,cgo
 
 // On systems that use glibc, calling malloc can create a new arena,
 // and creating a new arena can read /sys/devices/system/cpu/online.
diff --git a/libgo/go/os/exec/exec_posix_test.go b/libgo/go/os/exec/exec_posix_test.go
index 7b2c0c0..fd7fb42 100644
--- a/libgo/go/os/exec/exec_posix_test.go
+++ b/libgo/go/os/exec/exec_posix_test.go
@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris
-// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
 
 package exec_test
 
diff --git a/libgo/go/os/exec/exec_test.go b/libgo/go/os/exec/exec_test.go
index d854e0d..73aa35f 100644
--- a/libgo/go/os/exec/exec_test.go
+++ b/libgo/go/os/exec/exec_test.go
@@ -21,7 +21,9 @@ import (
 	"net/http/httptest"
 	"os"
 	"os/exec"
+	"os/exec/internal/fdtest"
 	"path/filepath"
+	"reflect"
 	"runtime"
 	"strconv"
 	"strings"
@@ -29,15 +31,10 @@ import (
 	"time"
 )
 
-// haveUnexpectedFDs is set at init time to report whether any
-// file descriptors were open at program start.
+// haveUnexpectedFDs is set at init time to report whether any file descriptors
+// were open at program start.
 var haveUnexpectedFDs bool
 
-// unfinalizedFiles holds files that should not be finalized,
-// because that would close the associated file descriptor,
-// which we don't want to do.
-var unfinalizedFiles []*os.File
-
 func init() {
 	if os.Getenv("GO_WANT_HELPER_PROCESS") == "1" {
 		return
@@ -49,21 +46,10 @@ func init() {
 		if poll.IsPollDescriptor(fd) {
 			continue
 		}
-		// We have no good portable way to check whether an FD is open.
-		// We use NewFile to create a *os.File, which lets us
-		// know whether it is open, but then we have to cope with
-		// the finalizer on the *os.File.
-		f := os.NewFile(fd, "")
-		if _, err := f.Stat(); err != nil {
-			// Close the file to clear the finalizer.
-			// We expect the Close to fail.
-			f.Close()
-		} else {
-			fmt.Printf("fd %d open at test start\n", fd)
+
+		if fdtest.Exists(fd) {
 			haveUnexpectedFDs = true
-			// Use a global variable to avoid running
-			// the finalizer, which would close the FD.
-			unfinalizedFiles = append(unfinalizedFiles, f)
+			return
 		}
 	}
 }
@@ -166,12 +152,10 @@ func TestCatGoodAndBadFile(t *testing.T) {
 	if _, ok := err.(*exec.ExitError); !ok {
 		t.Errorf("expected *exec.ExitError from cat combined; got %T: %v", err, err)
 	}
-	s := string(bs)
-	sp := strings.SplitN(s, "\n", 2)
-	if len(sp) != 2 {
-		t.Fatalf("expected two lines from cat; got %q", s)
+	errLine, body, ok := strings.Cut(string(bs), "\n")
+	if !ok {
+		t.Fatalf("expected two lines from cat; got %q", bs)
 	}
-	errLine, body := sp[0], sp[1]
 	if !strings.HasPrefix(errLine, "Error: open /bogus/file.foo") {
 		t.Errorf("expected stderr to complain about file; got %q", errLine)
 	}
@@ -379,50 +363,21 @@ func TestStdinCloseRace(t *testing.T) {
 
 // Issue 5071
 func TestPipeLookPathLeak(t *testing.T) {
-	// If we are reading from /proc/self/fd we (should) get an exact result.
-	tolerance := 0
-
-	// Reading /proc/self/fd is more reliable than calling lsof, so try that
-	// first.
-	numOpenFDs := func() (int, []byte, error) {
-		fds, err := os.ReadDir("/proc/self/fd")
-		if err != nil {
-			return 0, nil, err
-		}
-		return len(fds), nil, nil
+	if runtime.GOOS == "windows" {
+		t.Skip("we don't currently suppore counting open handles on windows")
 	}
-	want, before, err := numOpenFDs()
-	if err != nil {
-		// We encountered a problem reading /proc/self/fd (we might be on
-		// a platform that doesn't have it). Fall back onto lsof.
-		t.Logf("using lsof because: %v", err)
-		numOpenFDs = func() (int, []byte, error) {
-			// Android's stock lsof does not obey the -p option,
-			// so extra filtering is needed.
-			// https://golang.org/issue/10206
-			if runtime.GOOS == "android" {
-				// numOpenFDsAndroid handles errors itself and
-				// might skip or fail the test.
-				n, lsof := numOpenFDsAndroid(t)
-				return n, lsof, nil
-			}
-			lsof, err := exec.Command("lsof", "-b", "-n", "-p", strconv.Itoa(os.Getpid())).Output()
-			return bytes.Count(lsof, []byte("\n")), lsof, err
-		}
-
-		// lsof may see file descriptors associated with the fork itself,
-		// so we allow some extra margin if we have to use it.
-		// https://golang.org/issue/19243
-		tolerance = 5
 
-		// Retry reading the number of open file descriptors.
-		want, before, err = numOpenFDs()
-		if err != nil {
-			t.Log(err)
-			t.Skipf("skipping test; error finding or running lsof")
+	openFDs := func() []uintptr {
+		var fds []uintptr
+		for i := uintptr(0); i < 100; i++ {
+			if fdtest.Exists(i) {
+				fds = append(fds, i)
+			}
 		}
+		return fds
 	}
 
+	want := openFDs()
 	for i := 0; i < 6; i++ {
 		cmd := exec.Command("something-that-does-not-exist-executable")
 		cmd.StdoutPipe()
@@ -432,59 +387,10 @@ func TestPipeLookPathLeak(t *testing.T) {
 			t.Fatal("unexpected success")
 		}
 	}
-	got, after, err := numOpenFDs()
-	if err != nil {
-		// numOpenFDs has already succeeded once, it should work here.
-		t.Errorf("unexpected failure: %v", err)
-	}
-	if got-want > tolerance {
-		t.Errorf("number of open file descriptors changed: got %v, want %v", got, want)
-		if before != nil {
-			t.Errorf("before:\n%v\n", before)
-		}
-		if after != nil {
-			t.Errorf("after:\n%v\n", after)
-		}
-	}
-}
-
-func numOpenFDsAndroid(t *testing.T) (n int, lsof []byte) {
-	raw, err := exec.Command("lsof").Output()
-	if err != nil {
-		t.Skip("skipping test; error finding or running lsof")
-	}
-
-	// First find the PID column index by parsing the first line, and
-	// select lines containing pid in the column.
-	pid := []byte(strconv.Itoa(os.Getpid()))
-	pidCol := -1
-
-	s := bufio.NewScanner(bytes.NewReader(raw))
-	for s.Scan() {
-		line := s.Bytes()
-		fields := bytes.Fields(line)
-		if pidCol < 0 {
-			for i, v := range fields {
-				if bytes.Equal(v, []byte("PID")) {
-					pidCol = i
-					break
-				}
-			}
-			lsof = append(lsof, line...)
-			continue
-		}
-		if bytes.Equal(fields[pidCol], pid) {
-			lsof = append(lsof, '\n')
-			lsof = append(lsof, line...)
-		}
-	}
-	if pidCol < 0 {
-		t.Fatal("error processing lsof output: unexpected header format")
-	}
-	if err := s.Err(); err != nil {
-		t.Fatalf("error processing lsof output: %v", err)
+	got := openFDs()
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("set of open file descriptors changed: got %v, want %v", got, want)
 	}
-	return bytes.Count(lsof, []byte("\n")), lsof
 }
 
 func TestExtraFilesFDShuffle(t *testing.T) {
@@ -794,7 +700,7 @@ func TestHelperProcess(*testing.T) {
 	cmd, args := args[0], args[1:]
 	switch cmd {
 	case "echo":
-		iargs := []interface{}{}
+		iargs := []any{}
 		for _, s := range args {
 			iargs = append(iargs, s)
 		}
@@ -1048,6 +954,14 @@ func TestContext(t *testing.T) {
 }
 
 func TestContextCancel(t *testing.T) {
+	if runtime.GOOS == "netbsd" && runtime.GOARCH == "arm64" {
+		testenv.SkipFlaky(t, 42061)
+	}
+
+	// To reduce noise in the final goroutine dump,
+	// let other parallel tests complete if possible.
+	t.Parallel()
+
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 	c := helperCommandContext(t, ctx, "cat")
@@ -1072,14 +986,25 @@ func TestContextCancel(t *testing.T) {
 	// Calling cancel should have killed the process, so writes
 	// should now fail.  Give the process a little while to die.
 	start := time.Now()
+	delay := 1 * time.Millisecond
 	for {
 		if _, err := io.WriteString(stdin, "echo"); err != nil {
 			break
 		}
+
 		if time.Since(start) > time.Minute {
-			t.Fatal("canceling context did not stop program")
+			// Panic instead of calling t.Fatal so that we get a goroutine dump.
+			// We want to know exactly what the os/exec goroutines got stuck on.
+			panic("canceling context did not stop program")
+		}
+
+		// Back off exponentially (up to 1-second sleeps) to give the OS time to
+		// terminate the process.
+		delay *= 2
+		if delay > 1*time.Second {
+			delay = 1 * time.Second
 		}
-		time.Sleep(time.Millisecond)
+		time.Sleep(delay)
 	}
 
 	if err := c.Wait(); err == nil {
diff --git a/libgo/go/os/exec/exec_unix.go b/libgo/go/os/exec/exec_unix.go
index 467c069..c20f352 100644
--- a/libgo/go/os/exec/exec_unix.go
+++ b/libgo/go/os/exec/exec_unix.go
@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build !plan9 && !windows
-// +build !plan9,!windows
 
 package exec
 
diff --git a/libgo/go/os/exec/exec_windows_test.go b/libgo/go/os/exec/exec_windows_test.go
index fbccffe..8e31e47 100644
--- a/libgo/go/os/exec/exec_windows_test.go
+++ b/libgo/go/os/exec/exec_windows_test.go
@@ -3,13 +3,13 @@
 // license that can be found in the LICENSE file.
 
 //go:build windows
-// +build windows
 
 package exec_test
 
 import (
 	"io"
 	"os"
+	"os/exec"
 	"strconv"
 	"syscall"
 	"testing"
@@ -41,3 +41,16 @@ func TestPipePassing(t *testing.T) {
 		t.Error(err)
 	}
 }
+
+func TestNoInheritHandles(t *testing.T) {
+	cmd := exec.Command("cmd", "/c exit 88")
+	cmd.SysProcAttr = &syscall.SysProcAttr{NoInheritHandles: true}
+	err := cmd.Run()
+	exitError, ok := err.(*exec.ExitError)
+	if !ok {
+		t.Fatalf("got error %v; want ExitError", err)
+	}
+	if exitError.ExitCode() != 88 {
+		t.Fatalf("got exit code %d; want 88", exitError.ExitCode())
+	}
+}
diff --git a/libgo/go/os/exec/internal/fdtest/exists_js.go b/libgo/go/os/exec/internal/fdtest/exists_js.go
new file mode 100644
index 0000000..a7ce33c
--- /dev/null
+++ b/libgo/go/os/exec/internal/fdtest/exists_js.go
@@ -0,0 +1,18 @@
+// Copyright 2021 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.
+
+//go:build js
+
+package fdtest
+
+import (
+	"syscall"
+)
+
+// Exists returns true if fd is a valid file descriptor.
+func Exists(fd uintptr) bool {
+	var s syscall.Stat_t
+	err := syscall.Fstat(int(fd), &s)
+	return err != syscall.EBADF
+}
diff --git a/libgo/go/os/exec/internal/fdtest/exists_plan9.go b/libgo/go/os/exec/internal/fdtest/exists_plan9.go
new file mode 100644
index 0000000..8886e06
--- /dev/null
+++ b/libgo/go/os/exec/internal/fdtest/exists_plan9.go
@@ -0,0 +1,20 @@
+// Copyright 2021 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.
+
+//go:build plan9
+
+package fdtest
+
+import (
+	"syscall"
+)
+
+const errBadFd = syscall.ErrorString("fd out of range or not open")
+
+// Exists returns true if fd is a valid file descriptor.
+func Exists(fd uintptr) bool {
+	var buf [1]byte
+	_, err := syscall.Fstat(int(fd), buf[:])
+	return err != errBadFd
+}
diff --git a/libgo/go/os/exec/internal/fdtest/exists_test.go b/libgo/go/os/exec/internal/fdtest/exists_test.go
new file mode 100644
index 0000000..a02dddf
--- /dev/null
+++ b/libgo/go/os/exec/internal/fdtest/exists_test.go
@@ -0,0 +1,21 @@
+// Copyright 2021 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 fdtest
+
+import (
+	"os"
+	"runtime"
+	"testing"
+)
+
+func TestExists(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("Exists not implemented for windows")
+	}
+
+	if !Exists(os.Stdout.Fd()) {
+		t.Errorf("Exists(%d) got false want true", os.Stdout.Fd())
+	}
+}
diff --git a/libgo/go/os/exec/internal/fdtest/exists_unix.go b/libgo/go/os/exec/internal/fdtest/exists_unix.go
new file mode 100644
index 0000000..49f264c
--- /dev/null
+++ b/libgo/go/os/exec/internal/fdtest/exists_unix.go
@@ -0,0 +1,19 @@
+// Copyright 2021 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.
+
+//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris
+
+// Package fdtest provides test helpers for working with file descriptors across exec.
+package fdtest
+
+import (
+	"syscall"
+)
+
+// Exists returns true if fd is a valid file descriptor.
+func Exists(fd uintptr) bool {
+	var s syscall.Stat_t
+	err := syscall.Fstat(int(fd), &s)
+	return err != syscall.EBADF
+}
diff --git a/libgo/go/os/exec/internal/fdtest/exists_windows.go b/libgo/go/os/exec/internal/fdtest/exists_windows.go
new file mode 100644
index 0000000..72b8ccf
--- /dev/null
+++ b/libgo/go/os/exec/internal/fdtest/exists_windows.go
@@ -0,0 +1,12 @@
+// Copyright 2021 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.
+
+//go:build windows
+
+package fdtest
+
+// Exists is not implemented on windows and panics.
+func Exists(fd uintptr) bool {
+	panic("unimplemented")
+}
diff --git a/libgo/go/os/exec/lp_js.go b/libgo/go/os/exec/lp_js.go
index 4eac25f..54ddc4d 100644
--- a/libgo/go/os/exec/lp_js.go
+++ b/libgo/go/os/exec/lp_js.go
@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build js && wasm
-// +build js,wasm
 
 package exec
 
diff --git a/libgo/go/os/exec/lp_unix.go b/libgo/go/os/exec/lp_unix.go
index ebecc74..0935ab9 100644
--- a/libgo/go/os/exec/lp_unix.go
+++ b/libgo/go/os/exec/lp_unix.go
@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build aix || darwin || dragonfly || freebsd || hurd || linux || netbsd || openbsd || solaris
-// +build aix darwin dragonfly freebsd hurd linux netbsd openbsd solaris
 
 package exec
 
diff --git a/libgo/go/os/exec/lp_unix_test.go b/libgo/go/os/exec/lp_unix_test.go
index fe4df1a..bf602fc 100644
--- a/libgo/go/os/exec/lp_unix_test.go
+++ b/libgo/go/os/exec/lp_unix_test.go
@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build aix || darwin || dragonfly || freebsd || hurd || linux || netbsd || openbsd || solaris
-// +build aix darwin dragonfly freebsd hurd linux netbsd openbsd solaris
 
 package exec
 
diff --git a/libgo/go/os/exec/read3.go b/libgo/go/os/exec/read3.go
index a8c7183..10cbfbd 100644
--- a/libgo/go/os/exec/read3.go
+++ b/libgo/go/os/exec/read3.go
@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build ignore
-// +build ignore
 
 // This is a test program that verifies that it can read from
 // descriptor 3 and that no other descriptors are open.
@@ -19,12 +18,15 @@ import (
 	"io"
 	"os"
 	"os/exec"
+	"os/exec/internal/fdtest"
 	"runtime"
 	"strings"
 )
 
 func main() {
 	fd3 := os.NewFile(3, "fd3")
+	defer fd3.Close()
+
 	bs, err := io.ReadAll(fd3)
 	if err != nil {
 		fmt.Printf("ReadAll from fd 3: %v\n", err)
@@ -38,65 +40,52 @@ func main() {
 	// descriptor from parent == 3
 	// All descriptors 4 and up should be available,
 	// except for any used by the network poller.
-	var files []*os.File
-	for wantfd := uintptr(4); wantfd <= 100; wantfd++ {
-		if poll.IsPollDescriptor(wantfd) {
+	for fd := uintptr(4); fd <= 100; fd++ {
+		if poll.IsPollDescriptor(fd) {
 			continue
 		}
-		f, err := os.Open(os.Args[0])
-		if err != nil {
-			fmt.Printf("error opening file with expected fd %d: %v", wantfd, err)
-			os.Exit(1)
+
+		if !fdtest.Exists(fd) {
+			continue
 		}
-		if got := f.Fd(); got != wantfd {
-			fmt.Printf("leaked parent file. fd = %d; want %d\n", got, wantfd)
-			fdfile := fmt.Sprintf("/proc/self/fd/%d", wantfd)
-			link, err := os.Readlink(fdfile)
-			fmt.Printf("readlink(%q) = %q, %v\n", fdfile, link, err)
-			var args []string
-			switch runtime.GOOS {
-			case "plan9":
-				args = []string{fmt.Sprintf("/proc/%d/fd", os.Getpid())}
-			case "aix", "solaris", "illumos":
-				args = []string{fmt.Sprint(os.Getpid())}
-			default:
-				args = []string{"-p", fmt.Sprint(os.Getpid())}
-			}
 
-			// Determine which command to use to display open files.
-			ofcmd := "lsof"
-			switch runtime.GOOS {
-			case "dragonfly", "freebsd", "netbsd", "openbsd":
-				ofcmd = "fstat"
-			case "plan9":
-				ofcmd = "/bin/cat"
-			case "aix":
-				ofcmd = "procfiles"
-			case "solaris", "illumos":
-				ofcmd = "pfiles"
-			}
+		fmt.Printf("leaked parent file. fdtest.Exists(%d) got true want false\n", fd)
+
+		fdfile := fmt.Sprintf("/proc/self/fd/%d", fd)
+		link, err := os.Readlink(fdfile)
+		fmt.Printf("readlink(%q) = %q, %v\n", fdfile, link, err)
 
-			cmd := exec.Command(ofcmd, args...)
-			out, err := cmd.CombinedOutput()
-			if err != nil {
-				fmt.Fprintf(os.Stderr, "%s failed: %v\n", strings.Join(cmd.Args, " "), err)
-			}
-			fmt.Printf("%s", out)
-			os.Exit(1)
+		var args []string
+		switch runtime.GOOS {
+		case "plan9":
+			args = []string{fmt.Sprintf("/proc/%d/fd", os.Getpid())}
+		case "aix", "solaris", "illumos":
+			args = []string{fmt.Sprint(os.Getpid())}
+		default:
+			args = []string{"-p", fmt.Sprint(os.Getpid())}
 		}
-		files = append(files, f)
-	}
 
-	for _, f := range files {
-		f.Close()
-	}
+		// Determine which command to use to display open files.
+		ofcmd := "lsof"
+		switch runtime.GOOS {
+		case "dragonfly", "freebsd", "netbsd", "openbsd":
+			ofcmd = "fstat"
+		case "plan9":
+			ofcmd = "/bin/cat"
+		case "aix":
+			ofcmd = "procfiles"
+		case "solaris", "illumos":
+			ofcmd = "pfiles"
+		}
 
-	// Referring to fd3 here ensures that it is not
-	// garbage collected, and therefore closed, while
-	// executing the wantfd loop above. It doesn't matter
-	// what we do with fd3 as long as we refer to it;
-	// closing it is the easy choice.
-	fd3.Close()
+		cmd := exec.Command(ofcmd, args...)
+		out, err := cmd.CombinedOutput()
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "%s failed: %v\n", strings.Join(cmd.Args, " "), err)
+		}
+		fmt.Printf("%s", out)
+		os.Exit(1)
+	}
 
 	os.Stdout.Write(bs)
 }