build: separate compiler and libs

compiler/internal/lib/os/env.go

@@ -0,0 +1,159 @@
+// Copyright 2010 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.
+
+// General environment variables.
+
+package os
+
+import (
+	"syscall"
+)
+
+// Expand replaces ${var} or $var in the string based on the mapping function.
+// For example, os.ExpandEnv(s) is equivalent to os.Expand(s, os.Getenv).
+func Expand(s string, mapping func(string) string) string {
+	var buf []byte
+	// ${} is all ASCII, so bytes are fine for this operation.
+	i := 0
+	for j := 0; j < len(s); j++ {
+		if s[j] == '$' && j+1 < len(s) {
+			if buf == nil {
+				buf = make([]byte, 0, 2*len(s))
+			}
+			buf = append(buf, s[i:j]...)
+			name, w := getShellName(s[j+1:])
+			if name == "" && w > 0 {
+				// Encountered invalid syntax; eat the
+				// characters.
+			} else if name == "" {
+				// Valid syntax, but $ was not followed by a
+				// name. Leave the dollar character untouched.
+				buf = append(buf, s[j])
+			} else {
+				buf = append(buf, mapping(name)...)
+			}
+			j += w
+			i = j + 1
+		}
+	}
+	if buf == nil {
+		return s
+	}
+	return string(buf) + s[i:]
+}
+
+// ExpandEnv replaces ${var} or $var in the string according to the values
+// of the current environment variables. References to undefined
+// variables are replaced by the empty string.
+func ExpandEnv(s string) string {
+	return Expand(s, Getenv)
+}
+
+// isShellSpecialVar reports whether the character identifies a special
+// shell variable such as $*.
+func isShellSpecialVar(c uint8) bool {
+	switch c {
+	case '*', '#', '$', '@', '!', '?', '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
+		return true
+	}
+	return false
+}
+
+// isAlphaNum reports whether the byte is an ASCII letter, number, or underscore.
+func isAlphaNum(c uint8) bool {
+	return c == '_' || '0' <= c && c <= '9' || 'a' <= c && c <= 'z' || 'A' <= c && c <= 'Z'
+}
+
+// getShellName returns the name that begins the string and the number of bytes
+// consumed to extract it. If the name is enclosed in {}, it's part of a ${}
+// expansion and two more bytes are needed than the length of the name.
+func getShellName(s string) (string, int) {
+	switch {
+	case s[0] == '{':
+		if len(s) > 2 && isShellSpecialVar(s[1]) && s[2] == '}' {
+			return s[1:2], 3
+		}
+		// Scan to closing brace
+		for i := 1; i < len(s); i++ {
+			if s[i] == '}' {
+				if i == 1 {
+					return "", 2 // Bad syntax; eat "${}"
+				}
+				return s[1:i], i + 1
+			}
+		}
+		return "", 1 // Bad syntax; eat "${"
+	case isShellSpecialVar(s[0]):
+		return s[0:1], 1
+	}
+	// Scan alphanumerics.
+	var i int
+	for i = 0; i < len(s) && isAlphaNum(s[i]); i++ {
+	}
+	return s[:i], i
+}
+
+// Getenv retrieves the value of the environment variable named by the key.
+// It returns the value, which will be empty if the variable is not present.
+// To distinguish between an empty value and an unset value, use LookupEnv.
+func Getenv(key string) string {
+	v, _ := syscall.Getenv(key)
+	return v
+}
+
+/* TODO(xsw):
+func Getenv(key string) string {
+	return c.GoString(os.Getenv(c.AllocaCStr(key)))
+}
+*/
+
+// LookupEnv retrieves the value of the environment variable named
+// by the key. If the variable is present in the environment the
+// value (which may be empty) is returned and the boolean is true.
+// Otherwise the returned value will be empty and the boolean will
+// be false.
+func LookupEnv(key string) (string, bool) {
+	return syscall.Getenv(key)
+}
+
+// Setenv sets the value of the environment variable named by the key.
+// It returns an error, if any.
+func Setenv(key, value string) error {
+	err := syscall.Setenv(key, value)
+	if err != nil {
+		return NewSyscallError("setenv", err)
+	}
+	return nil
+}
+
+/* TODO(xsw):
+func Setenv(key, value string) error {
+	ret := os.Setenv(c.AllocaCStr(key), c.AllocaCStr(value), 1)
+	if ret == 0 {
+		return nil
+	}
+	return &SyscallError{"setenv", syscall.Errno(ret)}
+}
+*/
+
+// Unsetenv unsets a single environment variable.
+func Unsetenv(key string) error {
+	return syscall.Unsetenv(key)
+}
+
+/* TODO(xsw):
+func Unsetenv(key string) error {
+	ret := os.Unsetenv(c.AllocaCStr(key))
+	if ret == 0 {
+		return nil
+	}
+	return syscall.Errno(ret)
+}
+*/
+
+// Environ returns a copy of strings representing the environment,
+// in the form "key=value".
+func Environ() []string {
+	return syscall.Environ()
+}

compiler/internal/lib/os/error.go

@@ -0,0 +1,144 @@
+// Copyright 2009 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 os
+
+import (
+	"io/fs"
+	"syscall"
+)
+
+// Portable analogs of some common system call errors.
+//
+// Errors returned from this package may be tested against these errors
+// with errors.Is.
+var (
+	// ErrInvalid indicates an invalid argument.
+	// Methods on File will return this error when the receiver is nil.
+	ErrInvalid = fs.ErrInvalid // "invalid argument"
+
+	ErrPermission = fs.ErrPermission // "permission denied"
+	ErrExist      = fs.ErrExist      // "file already exists"
+	ErrNotExist   = fs.ErrNotExist   // "file does not exist"
+	ErrClosed     = fs.ErrClosed     // "file already closed"
+
+	// TODO(xsw):
+	// ErrNoDeadline       = errNoDeadline()       // "file type does not support deadline"
+	// ErrDeadlineExceeded = errDeadlineExceeded() // "i/o timeout"
+)
+
+// func errNoDeadline() error { return poll.ErrNoDeadline }
+
+// errDeadlineExceeded returns the value for os.ErrDeadlineExceeded.
+// This error comes from the internal/poll package, which is also
+// used by package net. Doing it this way ensures that the net
+// package will return os.ErrDeadlineExceeded for an exceeded deadline,
+// as documented by net.Conn.SetDeadline, without requiring any extra
+// work in the net package and without requiring the internal/poll
+// package to import os (which it can't, because that would be circular).
+// func errDeadlineExceeded() error { return poll.ErrDeadlineExceeded }
+
+type timeout interface {
+	Timeout() bool
+}
+
+// PathError records an error and the operation and file path that caused it.
+type PathError = fs.PathError
+
+// SyscallError records an error from a specific system call.
+type SyscallError struct {
+	Syscall string
+	Err     error
+}
+
+func (e *SyscallError) Error() string { return e.Syscall + ": " + e.Err.Error() }
+
+func (e *SyscallError) Unwrap() error { return e.Err }
+
+// Timeout reports whether this error represents a timeout.
+func (e *SyscallError) Timeout() bool {
+	t, ok := e.Err.(timeout)
+	return ok && t.Timeout()
+}
+
+// NewSyscallError returns, as an error, a new SyscallError
+// with the given system call name and error details.
+// As a convenience, if err is nil, NewSyscallError returns nil.
+func NewSyscallError(syscall string, err error) error {
+	if err == nil {
+		return nil
+	}
+	return &SyscallError{syscall, err}
+}
+
+// IsExist returns a boolean indicating whether the error is known to report
+// that a file or directory already exists. It is satisfied by ErrExist as
+// well as some syscall errors.
+//
+// This function predates errors.Is. It only supports errors returned by
+// the os package. New code should use errors.Is(err, fs.ErrExist).
+func IsExist(err error) bool {
+	return underlyingErrorIs(err, ErrExist)
+}
+
+// IsNotExist returns a boolean indicating whether the error is known to
+// report that a file or directory does not exist. It is satisfied by
+// ErrNotExist as well as some syscall errors.
+//
+// This function predates errors.Is. It only supports errors returned by
+// the os package. New code should use errors.Is(err, fs.ErrNotExist).
+func IsNotExist(err error) bool {
+	return underlyingErrorIs(err, ErrNotExist)
+}
+
+// IsPermission returns a boolean indicating whether the error is known to
+// report that permission is denied. It is satisfied by ErrPermission as well
+// as some syscall errors.
+//
+// This function predates errors.Is. It only supports errors returned by
+// the os package. New code should use errors.Is(err, fs.ErrPermission).
+func IsPermission(err error) bool {
+	return underlyingErrorIs(err, ErrPermission)
+}
+
+// IsTimeout returns a boolean indicating whether the error is known
+// to report that a timeout occurred.
+//
+// This function predates errors.Is, and the notion of whether an
+// error indicates a timeout can be ambiguous. For example, the Unix
+// error EWOULDBLOCK sometimes indicates a timeout and sometimes does not.
+// New code should use errors.Is with a value appropriate to the call
+// returning the error, such as os.ErrDeadlineExceeded.
+func IsTimeout(err error) bool {
+	terr, ok := underlyingError(err).(timeout)
+	return ok && terr.Timeout()
+}
+
+type syscallErrorType = syscall.Errno
+
+func underlyingErrorIs(err, target error) bool {
+	// Note that this function is not errors.Is:
+	// underlyingError only unwraps the specific error-wrapping types
+	// that it historically did, not all errors implementing Unwrap().
+	err = underlyingError(err)
+	if err == target {
+		return true
+	}
+	// To preserve prior behavior, only examine syscall errors.
+	e, ok := err.(syscallErrorType)
+	return ok && e.Is(target)
+}
+
+// underlyingError returns the underlying error for known os error types.
+func underlyingError(err error) error {
+	switch err := err.(type) {
+	case *PathError:
+		return err.Err
+	case *LinkError:
+		return err.Err
+	case *SyscallError:
+		return err.Err
+	}
+	return err
+}

compiler/internal/lib/os/exec.go

@@ -0,0 +1,172 @@
+// Copyright 2009 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 os
+
+import (
+	"errors"
+	"runtime"
+	"sync"
+	"sync/atomic"
+	"syscall"
+	"time"
+)
+
+// ErrProcessDone indicates a Process has finished.
+var ErrProcessDone = errors.New("os: process already finished")
+
+// Process stores the information about a process created by StartProcess.
+type Process struct {
+	Pid    int
+	handle uintptr      // handle is accessed atomically on Windows
+	isdone atomic.Bool  // process has been successfully waited on
+	sigMu  sync.RWMutex // avoid race between wait and signal
+}
+
+func newProcess(pid int, handle uintptr) *Process {
+	p := &Process{Pid: pid, handle: handle}
+	runtime.SetFinalizer(p, (*Process).Release)
+	return p
+}
+
+func (p *Process) setDone() {
+	p.isdone.Store(true)
+}
+
+func (p *Process) done() bool {
+	return p.isdone.Load()
+}
+
+// ProcAttr holds the attributes that will be applied to a new process
+// started by StartProcess.
+type ProcAttr struct {
+	// If Dir is non-empty, the child changes into the directory before
+	// creating the process.
+	Dir string
+	// If Env is non-nil, it gives the environment variables for the
+	// new process in the form returned by Environ.
+	// If it is nil, the result of Environ will be used.
+	Env []string
+	// Files specifies the open files inherited by the new process. The
+	// first three entries correspond to standard input, standard output, and
+	// standard error. An implementation may support additional entries,
+	// depending on the underlying operating system. A nil entry corresponds
+	// to that file being closed when the process starts.
+	// On Unix systems, StartProcess will change these File values
+	// to blocking mode, which means that SetDeadline will stop working
+	// and calling Close will not interrupt a Read or Write.
+	Files []*File
+
+	// Operating system-specific process creation attributes.
+	// Note that setting this field means that your program
+	// may not execute properly or even compile on some
+	// operating systems.
+	Sys *syscall.SysProcAttr
+}
+
+// A Signal represents an operating system signal.
+// The usual underlying implementation is operating system-dependent:
+// on Unix it is syscall.Signal.
+type Signal interface {
+	String() string
+	Signal() // to distinguish from other Stringers
+}
+
+// FindProcess looks for a running process by its pid.
+//
+// The Process it returns can be used to obtain information
+// about the underlying operating system process.
+//
+// On Unix systems, FindProcess always succeeds and returns a Process
+// for the given pid, regardless of whether the process exists. To test whether
+// the process actually exists, see whether p.Signal(syscall.Signal(0)) reports
+// an error.
+func FindProcess(pid int) (*Process, error) {
+	return findProcess(pid)
+}
+
+// StartProcess starts a new process with the program, arguments and attributes
+// specified by name, argv and attr. The argv slice will become os.Args in the
+// new process, so it normally starts with the program name.
+//
+// If the calling goroutine has locked the operating system thread
+// with runtime.LockOSThread and modified any inheritable OS-level
+// thread state (for example, Linux or Plan 9 name spaces), the new
+// process will inherit the caller's thread state.
+//
+// StartProcess is a low-level interface. The os/exec package provides
+// higher-level interfaces.
+//
+// If there is an error, it will be of type *PathError.
+func StartProcess(name string, argv []string, attr *ProcAttr) (*Process, error) {
+	return startProcess(name, argv, attr)
+}
+
+// Release releases any resources associated with the Process p,
+// rendering it unusable in the future.
+// Release only needs to be called if Wait is not.
+func (p *Process) Release() error {
+	return p.release()
+}
+
+// Kill causes the Process to exit immediately. Kill does not wait until
+// the Process has actually exited. This only kills the Process itself,
+// not any other processes it may have started.
+func (p *Process) Kill() error {
+	return p.kill()
+}
+
+// Wait waits for the Process to exit, and then returns a
+// ProcessState describing its status and an error, if any.
+// Wait releases any resources associated with the Process.
+// On most operating systems, the Process must be a child
+// of the current process or an error will be returned.
+func (p *Process) Wait() (*ProcessState, error) {
+	return p.wait()
+}
+
+// Signal sends a signal to the Process.
+// Sending Interrupt on Windows is not implemented.
+func (p *Process) Signal(sig Signal) error {
+	return p.signal(sig)
+}
+
+// UserTime returns the user CPU time of the exited process and its children.
+func (p *ProcessState) UserTime() time.Duration {
+	return p.userTime()
+}
+
+// SystemTime returns the system CPU time of the exited process and its children.
+func (p *ProcessState) SystemTime() time.Duration {
+	return p.systemTime()
+}
+
+// Exited reports whether the program has exited.
+// On Unix systems this reports true if the program exited due to calling exit,
+// but false if the program terminated due to a signal.
+func (p *ProcessState) Exited() bool {
+	return p.exited()
+}
+
+// Success reports whether the program exited successfully,
+// such as with exit status 0 on Unix.
+func (p *ProcessState) Success() bool {
+	return p.success()
+}
+
+// Sys returns system-dependent exit information about
+// the process. Convert it to the appropriate underlying
+// type, such as syscall.WaitStatus on Unix, to access its contents.
+func (p *ProcessState) Sys() any {
+	return p.sys()
+}
+
+// SysUsage returns system-dependent resource usage information about
+// the exited process. Convert it to the appropriate underlying
+// type, such as *syscall.Rusage on Unix, to access its contents.
+// (On Unix, *syscall.Rusage matches struct rusage as defined in the
+// getrusage(2) manual page.)
+func (p *ProcessState) SysUsage() any {
+	return p.sysUsage()
+}

compiler/internal/lib/os/exec/exec_plan9.go

@@ -0,0 +1,19 @@
+// Copyright 2019 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 exec
+
+import "io/fs"
+
+// skipStdinCopyError optionally specifies a function which reports
+// whether the provided stdin copy error should be ignored.
+func skipStdinCopyError(err error) bool {
+	// Ignore hungup errors copying to stdin if the program
+	// completed successfully otherwise.
+	// See Issue 35753.
+	pe, ok := err.(*fs.PathError)
+	return ok &&
+		pe.Op == "write" && pe.Path == "|1" &&
+		pe.Err.Error() == "i/o on hungup channel"
+}

compiler/internal/lib/os/exec/exec_unix.go

@@ -0,0 +1,24 @@
+// 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.
+
+//go:build !plan9 && !windows
+
+package exec
+
+import (
+	"io/fs"
+	"syscall"
+)
+
+// skipStdinCopyError optionally specifies a function which reports
+// whether the provided stdin copy error should be ignored.
+func skipStdinCopyError(err error) bool {
+	// Ignore EPIPE errors copying to stdin if the program
+	// completed successfully otherwise.
+	// See Issue 9173.
+	pe, ok := err.(*fs.PathError)
+	return ok &&
+		pe.Op == "write" && pe.Path == "|1" &&
+		pe.Err == syscall.EPIPE
+}

compiler/internal/lib/os/exec/exec_windows.go

@@ -0,0 +1,23 @@
+// Copyright 2017 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 exec
+
+import (
+	"io/fs"
+	"syscall"
+)
+
+// skipStdinCopyError optionally specifies a function which reports
+// whether the provided stdin copy error should be ignored.
+func skipStdinCopyError(err error) bool {
+	// Ignore ERROR_BROKEN_PIPE and ERROR_NO_DATA errors copying
+	// to stdin if the program completed successfully otherwise.
+	// See Issue 20445.
+	const _ERROR_NO_DATA = syscall.Errno(0xe8)
+	pe, ok := err.(*fs.PathError)
+	return ok &&
+		pe.Op == "write" && pe.Path == "|1" &&
+		(pe.Err == syscall.ERROR_BROKEN_PIPE || pe.Err == _ERROR_NO_DATA)
+}

compiler/internal/lib/os/exec/lp_plan9.go

@@ -0,0 +1,66 @@
+// Copyright 2011 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 exec
+
+import (
+	"errors"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// ErrNotFound is the error resulting if a path search failed to find an executable file.
+var ErrNotFound = errors.New("executable file not found in $path")
+
+func findExecutable(file string) error {
+	d, err := os.Stat(file)
+	if err != nil {
+		return err
+	}
+	if m := d.Mode(); !m.IsDir() && m&0111 != 0 {
+		return nil
+	}
+	return fs.ErrPermission
+}
+
+// LookPath searches for an executable named file in the
+// directories named by the path environment variable.
+// If file begins with "/", "#", "./", or "../", it is tried
+// directly and the path is not consulted.
+// On success, the result is an absolute path.
+//
+// In older versions of Go, LookPath could return a path relative to the current directory.
+// As of Go 1.19, LookPath will instead return that path along with an error satisfying
+// errors.Is(err, ErrDot). See the package documentation for more details.
+func LookPath(file string) (string, error) {
+	// skip the path lookup for these prefixes
+	skip := []string{"/", "#", "./", "../"}
+
+	for _, p := range skip {
+		if strings.HasPrefix(file, p) {
+			err := findExecutable(file)
+			if err == nil {
+				return file, nil
+			}
+			return "", &Error{file, err}
+		}
+	}
+
+	path := os.Getenv("path")
+	for _, dir := range filepath.SplitList(path) {
+		path := filepath.Join(dir, file)
+		if err := findExecutable(path); err == nil {
+			if !filepath.IsAbs(path) {
+				if execerrdot.Value() != "0" {
+					return path, &Error{file, ErrDot}
+				}
+				execerrdot.IncNonDefault()
+			}
+			return path, nil
+		}
+	}
+	return "", &Error{file, ErrNotFound}
+}

compiler/internal/lib/os/exec/lp_unix.go

@@ -0,0 +1,84 @@
+// Copyright 2010 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 unix
+
+package exec
+
+import (
+	"errors"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+	"syscall"
+)
+
+// ErrNotFound is the error resulting if a path search failed to find an executable file.
+var ErrNotFound = errors.New("executable file not found in $PATH")
+
+func findExecutable(file string) error {
+	d, err := os.Stat(file)
+	if err != nil {
+		return err
+	}
+	m := d.Mode()
+	if m.IsDir() {
+		return syscall.EISDIR
+	}
+	err = unixEaccess(file, unix_X_OK)
+	// ENOSYS means Eaccess is not available or not implemented.
+	// EPERM can be returned by Linux containers employing seccomp.
+	// In both cases, fall back to checking the permission bits.
+	if err == nil || (err != syscall.ENOSYS && err != syscall.EPERM) {
+		return err
+	}
+	if m&0111 != 0 {
+		return nil
+	}
+	return fs.ErrPermission
+}
+
+// LookPath searches for an executable named file in the
+// directories named by the PATH environment variable.
+// If file contains a slash, it is tried directly and the PATH is not consulted.
+// Otherwise, on success, the result is an absolute path.
+//
+// In older versions of Go, LookPath could return a path relative to the current directory.
+// As of Go 1.19, LookPath will instead return that path along with an error satisfying
+// errors.Is(err, ErrDot). See the package documentation for more details.
+func LookPath(file string) (string, error) {
+	// NOTE(rsc): I wish we could use the Plan 9 behavior here
+	// (only bypass the path if file begins with / or ./ or ../)
+	// but that would not match all the Unix shells.
+
+	if strings.Contains(file, "/") {
+		err := findExecutable(file)
+		if err == nil {
+			return file, nil
+		}
+		return "", &Error{file, err}
+	}
+	path := os.Getenv("PATH")
+	for _, dir := range filepath.SplitList(path) {
+		if dir == "" {
+			// Unix shell semantics: path element "" means "."
+			dir = "."
+		}
+		path := filepath.Join(dir, file)
+		if err := findExecutable(path); err == nil {
+			if !filepath.IsAbs(path) {
+				/* TODO(xsw):
+				if execerrdot.Value() != "0" {
+					return path, &Error{file, ErrDot}
+				}
+				execerrdot.IncNonDefault()
+				*/
+				panic("todo: exec.LookPath: !filepath.IsAbs(path)")
+			}
+			return path, nil
+		}
+	}
+	return "", &Error{file, ErrNotFound}
+}

compiler/internal/lib/os/exec/lp_wasm.go

@@ -0,0 +1,23 @@
+// Copyright 2018 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 wasm
+
+package exec
+
+import (
+	"errors"
+)
+
+// ErrNotFound is the error resulting if a path search failed to find an executable file.
+var ErrNotFound = errors.New("executable file not found in $PATH")
+
+// LookPath searches for an executable named file in the
+// directories named by the PATH environment variable.
+// If file contains a slash, it is tried directly and the PATH is not consulted.
+// The result may be an absolute path or a path relative to the current directory.
+func LookPath(file string) (string, error) {
+	// Wasm can not execute processes, so act as if there are no executables at all.
+	return "", &Error{file, ErrNotFound}
+}

compiler/internal/lib/os/exec/lp_windows.go

@@ -0,0 +1,145 @@
+// Copyright 2010 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 exec
+
+import (
+	"errors"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+	"syscall"
+)
+
+// ErrNotFound is the error resulting if a path search failed to find an executable file.
+var ErrNotFound = errors.New("executable file not found in %PATH%")
+
+func chkStat(file string) error {
+	d, err := os.Stat(file)
+	if err != nil {
+		return err
+	}
+	if d.IsDir() {
+		return fs.ErrPermission
+	}
+	return nil
+}
+
+func hasExt(file string) bool {
+	i := strings.LastIndex(file, ".")
+	if i < 0 {
+		return false
+	}
+	return strings.LastIndexAny(file, `:\/`) < i
+}
+
+func findExecutable(file string, exts []string) (string, error) {
+	if len(exts) == 0 {
+		return file, chkStat(file)
+	}
+	if hasExt(file) {
+		if chkStat(file) == nil {
+			return file, nil
+		}
+	}
+	for _, e := range exts {
+		if f := file + e; chkStat(f) == nil {
+			return f, nil
+		}
+	}
+	return "", fs.ErrNotExist
+}
+
+// LookPath searches for an executable named file in the
+// directories named by the PATH environment variable.
+// LookPath also uses PATHEXT environment variable to match
+// a suitable candidate.
+// If file contains a slash, it is tried directly and the PATH is not consulted.
+// Otherwise, on success, the result is an absolute path.
+//
+// In older versions of Go, LookPath could return a path relative to the current directory.
+// As of Go 1.19, LookPath will instead return that path along with an error satisfying
+// errors.Is(err, ErrDot). See the package documentation for more details.
+func LookPath(file string) (string, error) {
+	var exts []string
+	x := os.Getenv(`PATHEXT`)
+	if x != "" {
+		for _, e := range strings.Split(strings.ToLower(x), `;`) {
+			if e == "" {
+				continue
+			}
+			if e[0] != '.' {
+				e = "." + e
+			}
+			exts = append(exts, e)
+		}
+	} else {
+		exts = []string{".com", ".exe", ".bat", ".cmd"}
+	}
+
+	if strings.ContainsAny(file, `:\/`) {
+		f, err := findExecutable(file, exts)
+		if err == nil {
+			return f, nil
+		}
+		return "", &Error{file, err}
+	}
+
+	// On Windows, creating the NoDefaultCurrentDirectoryInExePath
+	// environment variable (with any value or no value!) signals that
+	// path lookups should skip the current directory.
+	// In theory we are supposed to call NeedCurrentDirectoryForExePathW
+	// "as the registry location of this environment variable can change"
+	// but that seems exceedingly unlikely: it would break all users who
+	// have configured their environment this way!
+	// https://docs.microsoft.com/en-us/windows/win32/api/processenv/nf-processenv-needcurrentdirectoryforexepathw
+	// See also go.dev/issue/43947.
+	var (
+		dotf   string
+		dotErr error
+	)
+	if _, found := syscall.Getenv("NoDefaultCurrentDirectoryInExePath"); !found {
+		if f, err := findExecutable(filepath.Join(".", file), exts); err == nil {
+			if execerrdot.Value() == "0" {
+				execerrdot.IncNonDefault()
+				return f, nil
+			}
+			dotf, dotErr = f, &Error{file, ErrDot}
+		}
+	}
+
+	path := os.Getenv("path")
+	for _, dir := range filepath.SplitList(path) {
+		if f, err := findExecutable(filepath.Join(dir, file), exts); err == nil {
+			if dotErr != nil {
+				// https://go.dev/issue/53536: if we resolved a relative path implicitly,
+				// and it is the same executable that would be resolved from the explicit %PATH%,
+				// prefer the explicit name for the executable (and, likely, no error) instead
+				// of the equivalent implicit name with ErrDot.
+				//
+				// Otherwise, return the ErrDot for the implicit path as soon as we find
+				// out that the explicit one doesn't match.
+				dotfi, dotfiErr := os.Lstat(dotf)
+				fi, fiErr := os.Lstat(f)
+				if dotfiErr != nil || fiErr != nil || !os.SameFile(dotfi, fi) {
+					return dotf, dotErr
+				}
+			}
+
+			if !filepath.IsAbs(f) {
+				if execerrdot.Value() != "0" {
+					return f, &Error{file, ErrDot}
+				}
+				execerrdot.IncNonDefault()
+			}
+			return f, nil
+		}
+	}
+
+	if dotErr != nil {
+		return dotf, dotErr
+	}
+	return "", &Error{file, ErrNotFound}
+}

compiler/internal/lib/os/exec/unix_constants.go

@@ -0,0 +1,13 @@
+// Copyright 2022 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 unix
+
+package exec
+
+const (
+	unix_R_OK = 0x4
+	unix_W_OK = 0x2
+	unix_X_OK = 0x1
+)

compiler/internal/lib/os/exec/unix_eaccess_linux.go

@@ -0,0 +1,15 @@
+// Copyright 2022 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 exec
+
+import (
+	"syscall"
+
+	"github.com/goplus/llgo/c/syscall/unix"
+)
+
+func unixEaccess(path string, mode uint32) error {
+	return syscall.Faccessat(unix.AT_FDCWD, path, mode, unix.AT_EACCESS)
+}

compiler/internal/lib/os/exec/unix_eaccess_other.go

@@ -0,0 +1,13 @@
+// Copyright 2022 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 unix && !linux
+
+package exec
+
+import "syscall"
+
+func unixEaccess(path string, mode uint32) error {
+	return syscall.ENOSYS
+}

compiler/internal/lib/os/exec_plan9.go

@@ -0,0 +1,149 @@
+// Copyright 2009 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 os
+
+import (
+	"internal/itoa"
+	"runtime"
+	"syscall"
+	"time"
+)
+
+// The only signal values guaranteed to be present in the os package
+// on all systems are Interrupt (send the process an interrupt) and
+// Kill (force the process to exit). Interrupt is not implemented on
+// Windows; using it with os.Process.Signal will return an error.
+var (
+	Interrupt Signal = syscall.Note("interrupt")
+	Kill      Signal = syscall.Note("kill")
+)
+
+func startProcess(name string, argv []string, attr *ProcAttr) (p *Process, err error) {
+	sysattr := &syscall.ProcAttr{
+		Dir: attr.Dir,
+		Env: attr.Env,
+		Sys: attr.Sys,
+	}
+
+	sysattr.Files = make([]uintptr, 0, len(attr.Files))
+	for _, f := range attr.Files {
+		sysattr.Files = append(sysattr.Files, f.Fd())
+	}
+
+	pid, h, e := syscall.StartProcess(name, argv, sysattr)
+	if e != nil {
+		return nil, &PathError{Op: "fork/exec", Path: name, Err: e}
+	}
+
+	return newProcess(pid, h), nil
+}
+
+func (p *Process) writeProcFile(file string, data string) error {
+	f, e := OpenFile("/proc/"+itoa.Itoa(p.Pid)+"/"+file, O_WRONLY, 0)
+	if e != nil {
+		return e
+	}
+	defer f.Close()
+	_, e = f.Write([]byte(data))
+	return e
+}
+
+func (p *Process) signal(sig Signal) error {
+	if p.done() {
+		return ErrProcessDone
+	}
+	if e := p.writeProcFile("note", sig.String()); e != nil {
+		return NewSyscallError("signal", e)
+	}
+	return nil
+}
+
+func (p *Process) kill() error {
+	return p.signal(Kill)
+}
+
+func (p *Process) wait() (ps *ProcessState, err error) {
+	var waitmsg syscall.Waitmsg
+
+	if p.Pid == -1 {
+		return nil, ErrInvalid
+	}
+	err = syscall.WaitProcess(p.Pid, &waitmsg)
+	if err != nil {
+		return nil, NewSyscallError("wait", err)
+	}
+
+	p.setDone()
+	ps = &ProcessState{
+		pid:    waitmsg.Pid,
+		status: &waitmsg,
+	}
+	return ps, nil
+}
+
+func (p *Process) release() error {
+	// NOOP for Plan 9.
+	p.Pid = -1
+	// no need for a finalizer anymore
+	runtime.SetFinalizer(p, nil)
+	return nil
+}
+
+func findProcess(pid int) (p *Process, err error) {
+	// NOOP for Plan 9.
+	return newProcess(pid, 0), nil
+}
+
+// ProcessState stores information about a process, as reported by Wait.
+type ProcessState struct {
+	pid    int              // The process's id.
+	status *syscall.Waitmsg // System-dependent status info.
+}
+
+// Pid returns the process id of the exited process.
+func (p *ProcessState) Pid() int {
+	return p.pid
+}
+
+func (p *ProcessState) exited() bool {
+	return p.status.Exited()
+}
+
+func (p *ProcessState) success() bool {
+	return p.status.ExitStatus() == 0
+}
+
+func (p *ProcessState) sys() any {
+	return p.status
+}
+
+func (p *ProcessState) sysUsage() any {
+	return p.status
+}
+
+func (p *ProcessState) userTime() time.Duration {
+	return time.Duration(p.status.Time[0]) * time.Millisecond
+}
+
+func (p *ProcessState) systemTime() time.Duration {
+	return time.Duration(p.status.Time[1]) * time.Millisecond
+}
+
+func (p *ProcessState) String() string {
+	if p == nil {
+		return "<nil>"
+	}
+	return "exit status: " + p.status.Msg
+}
+
+// ExitCode returns the exit code of the exited process, or -1
+// if the process hasn't exited or was terminated by a signal.
+func (p *ProcessState) ExitCode() int {
+	// return -1 if the process hasn't started.
+	if p == nil {
+		return -1
+	}
+	return p.status.ExitStatus()
+}

compiler/internal/lib/os/exec_posix.go

@@ -0,0 +1,138 @@
+// Copyright 2009 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 unix || (js && wasm) || wasip1 || windows
+
+package os
+
+import (
+	"runtime"
+	"syscall"
+
+	"github.com/goplus/llgo/compiler/internal/lib/internal/itoa"
+	"github.com/goplus/llgo/compiler/internal/lib/internal/syscall/execenv"
+)
+
+// The only signal values guaranteed to be present in the os package on all
+// systems are os.Interrupt (send the process an interrupt) and os.Kill (force
+// the process to exit). On Windows, sending os.Interrupt to a process with
+// os.Process.Signal is not implemented; it will return an error instead of
+// sending a signal.
+var (
+	Interrupt Signal = syscall.SIGINT
+	Kill      Signal = syscall.SIGKILL
+)
+
+func startProcess(name string, argv []string, attr *ProcAttr) (p *Process, err error) {
+	// If there is no SysProcAttr (ie. no Chroot or changed
+	// UID/GID), double-check existence of the directory we want
+	// to chdir into. We can make the error clearer this way.
+	if attr != nil && attr.Sys == nil && attr.Dir != "" {
+		if _, err := Stat(attr.Dir); err != nil {
+			pe := err.(*PathError)
+			pe.Op = "chdir"
+			return nil, pe
+		}
+	}
+
+	sysattr := &syscall.ProcAttr{
+		Dir: attr.Dir,
+		Env: attr.Env,
+		Sys: attr.Sys,
+	}
+	if sysattr.Env == nil {
+		sysattr.Env, err = execenv.Default(sysattr.Sys)
+		if err != nil {
+			return nil, err
+		}
+	}
+	sysattr.Files = make([]uintptr, 0, len(attr.Files))
+	for _, f := range attr.Files {
+		sysattr.Files = append(sysattr.Files, f.Fd())
+	}
+
+	pid, h, e := syscall.StartProcess(name, argv, sysattr)
+
+	// TODO(xsw):
+	// Make sure we don't run the finalizers of attr.Files.
+	// runtime.KeepAlive(attr)
+
+	if e != nil {
+		return nil, &PathError{Op: "fork/exec", Path: name, Err: e}
+	}
+
+	return newProcess(pid, h), nil
+}
+
+func (p *Process) kill() error {
+	return p.Signal(Kill)
+}
+
+// ProcessState stores information about a process, as reported by Wait.
+type ProcessState struct {
+	pid    int                // The process's id.
+	status syscall.WaitStatus // System-dependent status info.
+	rusage *syscall.Rusage
+}
+
+// Pid returns the process id of the exited process.
+func (p *ProcessState) Pid() int {
+	return p.pid
+}
+
+func (p *ProcessState) exited() bool {
+	return p.status.Exited()
+}
+
+func (p *ProcessState) success() bool {
+	return p.status.ExitStatus() == 0
+}
+
+func (p *ProcessState) sys() any {
+	return p.status
+}
+
+func (p *ProcessState) sysUsage() any {
+	return p.rusage
+}
+
+func (p *ProcessState) String() string {
+	if p == nil {
+		return "<nil>"
+	}
+	status := p.Sys().(syscall.WaitStatus)
+	res := ""
+	switch {
+	case status.Exited():
+		code := status.ExitStatus()
+		if runtime.GOOS == "windows" && uint(code) >= 1<<16 { // windows uses large hex numbers
+			res = "exit status " + uitox(uint(code))
+		} else { // unix systems use small decimal integers
+			res = "exit status " + itoa.Itoa(code) // unix
+		}
+	case status.Signaled():
+		res = "signal: " + status.Signal().String()
+	case status.Stopped():
+		res = "stop signal: " + status.StopSignal().String()
+		if status.StopSignal() == syscall.SIGTRAP && status.TrapCause() != 0 {
+			res += " (trap " + itoa.Itoa(status.TrapCause()) + ")"
+		}
+	case status.Continued():
+		res = "continued"
+	}
+	if status.CoreDump() {
+		res += " (core dumped)"
+	}
+	return res
+}
+
+// ExitCode returns the exit code of the exited process, or -1
+// if the process hasn't exited or was terminated by a signal.
+func (p *ProcessState) ExitCode() int {
+	// return -1 if the process hasn't started.
+	if p == nil {
+		return -1
+	}
+	return p.status.ExitStatus()
+}

compiler/internal/lib/os/exec_unix.go

@@ -0,0 +1,106 @@
+// Copyright 2009 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 unix || (js && wasm) || wasip1
+
+package os
+
+import (
+	"errors"
+	"runtime"
+	"syscall"
+	"time"
+)
+
+func (p *Process) wait() (ps *ProcessState, err error) {
+	if p.Pid == -1 {
+		return nil, syscall.EINVAL
+	}
+
+	// If we can block until Wait4 will succeed immediately, do so.
+	ready, err := p.blockUntilWaitable()
+	if err != nil {
+		return nil, err
+	}
+	if ready {
+		// Mark the process done now, before the call to Wait4,
+		// so that Process.signal will not send a signal.
+		p.setDone()
+		// Acquire a write lock on sigMu to wait for any
+		// active call to the signal method to complete.
+		p.sigMu.Lock()
+		p.sigMu.Unlock()
+	}
+
+	var (
+		status syscall.WaitStatus
+		rusage syscall.Rusage
+		pid1   int
+		e      error
+	)
+	for {
+		pid1, e = syscall.Wait4(p.Pid, &status, 0, &rusage)
+		if e != syscall.EINTR {
+			break
+		}
+	}
+	if e != nil {
+		return nil, NewSyscallError("wait", e)
+	}
+	if pid1 != 0 {
+		p.setDone()
+	}
+	ps = &ProcessState{
+		pid:    pid1,
+		status: status,
+		rusage: &rusage,
+	}
+	return ps, nil
+}
+
+func (p *Process) signal(sig Signal) error {
+	if p.Pid == -1 {
+		return errors.New("os: process already released")
+	}
+	if p.Pid == 0 {
+		return errors.New("os: process not initialized")
+	}
+	p.sigMu.RLock()
+	defer p.sigMu.RUnlock()
+	if p.done() {
+		return ErrProcessDone
+	}
+	s, ok := sig.(syscall.Signal)
+	if !ok {
+		return errors.New("os: unsupported signal type")
+	}
+	if e := syscall.Kill(p.Pid, s); e != nil {
+		if e == syscall.ESRCH {
+			return ErrProcessDone
+		}
+		return e
+	}
+	return nil
+}
+
+func (p *Process) release() error {
+	// NOOP for unix.
+	p.Pid = -1
+	// no need for a finalizer anymore
+	runtime.SetFinalizer(p, nil)
+	return nil
+}
+
+func findProcess(pid int) (p *Process, err error) {
+	// NOOP for unix.
+	return newProcess(pid, 0), nil
+}
+
+func (p *ProcessState) userTime() time.Duration {
+	return time.Duration(p.rusage.Utime.Nano()) * time.Nanosecond
+}
+
+func (p *ProcessState) systemTime() time.Duration {
+	return time.Duration(p.rusage.Stime.Nano()) * time.Nanosecond
+}

compiler/internal/lib/os/exec_windows.go

@@ -0,0 +1,183 @@
+// Copyright 2009 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 os
+
+import (
+	"internal/syscall/windows"
+	"runtime"
+	"sync/atomic"
+	"syscall"
+	"time"
+)
+
+func (p *Process) wait() (ps *ProcessState, err error) {
+	/* TODO(xsw):
+	handle := atomic.LoadUintptr(&p.handle)
+	s, e := syscall.WaitForSingleObject(syscall.Handle(handle), syscall.INFINITE)
+	switch s {
+	case syscall.WAIT_OBJECT_0:
+		break
+	case syscall.WAIT_FAILED:
+		return nil, NewSyscallError("WaitForSingleObject", e)
+	default:
+		return nil, errors.New("os: unexpected result from WaitForSingleObject")
+	}
+	var ec uint32
+	e = syscall.GetExitCodeProcess(syscall.Handle(handle), &ec)
+	if e != nil {
+		return nil, NewSyscallError("GetExitCodeProcess", e)
+	}
+	var u syscall.Rusage
+	e = syscall.GetProcessTimes(syscall.Handle(handle), &u.CreationTime, &u.ExitTime, &u.KernelTime, &u.UserTime)
+	if e != nil {
+		return nil, NewSyscallError("GetProcessTimes", e)
+	}
+	p.setDone()
+	// NOTE(brainman): It seems that sometimes process is not dead
+	// when WaitForSingleObject returns. But we do not know any
+	// other way to wait for it. Sleeping for a while seems to do
+	// the trick sometimes.
+	// See https://golang.org/issue/25965 for details.
+	defer time.Sleep(5 * time.Millisecond)
+	defer p.Release()
+	return &ProcessState{p.Pid, syscall.WaitStatus{ExitCode: ec}, &u}, nil
+	*/
+	panic("todo: os.Process.wait")
+}
+
+func (p *Process) signal(sig Signal) error {
+	handle := atomic.LoadUintptr(&p.handle)
+	if handle == uintptr(syscall.InvalidHandle) {
+		return syscall.EINVAL
+	}
+	if p.done() {
+		return ErrProcessDone
+	}
+	if sig == Kill {
+		var terminationHandle syscall.Handle
+		e := syscall.DuplicateHandle(^syscall.Handle(0), syscall.Handle(handle), ^syscall.Handle(0), &terminationHandle, syscall.PROCESS_TERMINATE, false, 0)
+		if e != nil {
+			return NewSyscallError("DuplicateHandle", e)
+		}
+		runtime.KeepAlive(p)
+		defer syscall.CloseHandle(terminationHandle)
+		e = syscall.TerminateProcess(syscall.Handle(terminationHandle), 1)
+		return NewSyscallError("TerminateProcess", e)
+	}
+	// TODO(rsc): Handle Interrupt too?
+	return syscall.Errno(syscall.EWINDOWS)
+}
+
+func (p *Process) release() error {
+	handle := atomic.SwapUintptr(&p.handle, uintptr(syscall.InvalidHandle))
+	if handle == uintptr(syscall.InvalidHandle) {
+		return syscall.EINVAL
+	}
+	e := syscall.CloseHandle(syscall.Handle(handle))
+	if e != nil {
+		return NewSyscallError("CloseHandle", e)
+	}
+	// no need for a finalizer anymore
+	runtime.SetFinalizer(p, nil)
+	return nil
+}
+
+func findProcess(pid int) (p *Process, err error) {
+	const da = syscall.STANDARD_RIGHTS_READ |
+		syscall.PROCESS_QUERY_INFORMATION | syscall.SYNCHRONIZE
+	h, e := syscall.OpenProcess(da, false, uint32(pid))
+	if e != nil {
+		return nil, NewSyscallError("OpenProcess", e)
+	}
+	return newProcess(pid, uintptr(h)), nil
+}
+
+func init() {
+	cmd := windows.UTF16PtrToString(syscall.GetCommandLine())
+	if len(cmd) == 0 {
+		arg0, _ := Executable()
+		Args = []string{arg0}
+	} else {
+		Args = commandLineToArgv(cmd)
+	}
+}
+
+// appendBSBytes appends n '\\' bytes to b and returns the resulting slice.
+func appendBSBytes(b []byte, n int) []byte {
+	for ; n > 0; n-- {
+		b = append(b, '\\')
+	}
+	return b
+}
+
+// readNextArg splits command line string cmd into next
+// argument and command line remainder.
+func readNextArg(cmd string) (arg []byte, rest string) {
+	var b []byte
+	var inquote bool
+	var nslash int
+	for ; len(cmd) > 0; cmd = cmd[1:] {
+		c := cmd[0]
+		switch c {
+		case ' ', '\t':
+			if !inquote {
+				return appendBSBytes(b, nslash), cmd[1:]
+			}
+		case '"':
+			b = appendBSBytes(b, nslash/2)
+			if nslash%2 == 0 {
+				// use "Prior to 2008" rule from
+				// http://daviddeley.com/autohotkey/parameters/parameters.htm
+				// section 5.2 to deal with double double quotes
+				if inquote && len(cmd) > 1 && cmd[1] == '"' {
+					b = append(b, c)
+					cmd = cmd[1:]
+				}
+				inquote = !inquote
+			} else {
+				b = append(b, c)
+			}
+			nslash = 0
+			continue
+		case '\\':
+			nslash++
+			continue
+		}
+		b = appendBSBytes(b, nslash)
+		nslash = 0
+		b = append(b, c)
+	}
+	return appendBSBytes(b, nslash), ""
+}
+
+// commandLineToArgv splits a command line into individual argument
+// strings, following the Windows conventions documented
+// at http://daviddeley.com/autohotkey/parameters/parameters.htm#WINARGV
+func commandLineToArgv(cmd string) []string {
+	var args []string
+	for len(cmd) > 0 {
+		if cmd[0] == ' ' || cmd[0] == '\t' {
+			cmd = cmd[1:]
+			continue
+		}
+		var arg []byte
+		arg, cmd = readNextArg(cmd)
+		args = append(args, string(arg))
+	}
+	return args
+}
+
+func ftToDuration(ft *syscall.Filetime) time.Duration {
+	n := int64(ft.HighDateTime)<<32 + int64(ft.LowDateTime) // in 100-nanosecond intervals
+	return time.Duration(n*100) * time.Nanosecond
+}
+
+func (p *ProcessState) userTime() time.Duration {
+	return ftToDuration(&p.rusage.UserTime)
+}
+
+func (p *ProcessState) systemTime() time.Duration {
+	return ftToDuration(&p.rusage.KernelTime)
+}

compiler/internal/lib/os/file.go

@@ -0,0 +1,530 @@
+// Copyright 2009 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 os
+
+import (
+	"errors"
+	"io"
+	"syscall"
+	"time"
+)
+
+// Name returns the name of the file as presented to Open.
+func (f *File) Name() string { return f.name }
+
+// Stdin, Stdout, and Stderr are open Files pointing to the standard input,
+// standard output, and standard error file descriptors.
+//
+// Note that the Go runtime writes to standard error for panics and crashes;
+// closing Stderr may cause those messages to go elsewhere, perhaps
+// to a file opened later.
+var (
+	Stdin  = NewFile(uintptr(syscall.Stdin), "/dev/stdin")
+	Stdout = NewFile(uintptr(syscall.Stdout), "/dev/stdout")
+	Stderr = NewFile(uintptr(syscall.Stderr), "/dev/stderr")
+)
+
+// Flags to OpenFile wrapping those of the underlying system. Not all
+// flags may be implemented on a given system.
+const (
+	// Exactly one of O_RDONLY, O_WRONLY, or O_RDWR must be specified.
+	O_RDONLY int = syscall.O_RDONLY // open the file read-only.
+	O_WRONLY int = syscall.O_WRONLY // open the file write-only.
+	O_RDWR   int = syscall.O_RDWR   // open the file read-write.
+	// The remaining values may be or'ed in to control behavior.
+	O_APPEND int = syscall.O_APPEND // append data to the file when writing.
+	O_CREATE int = syscall.O_CREAT  // create a new file if none exists.
+	O_EXCL   int = syscall.O_EXCL   // used with O_CREATE, file must not exist.
+	O_SYNC   int = syscall.O_SYNC   // open for synchronous I/O.
+	O_TRUNC  int = syscall.O_TRUNC  // truncate regular writable file when opened.
+)
+
+// Seek whence values.
+//
+// Deprecated: Use io.SeekStart, io.SeekCurrent, and io.SeekEnd.
+const (
+	SEEK_SET int = 0 // seek relative to the origin of the file
+	SEEK_CUR int = 1 // seek relative to the current offset
+	SEEK_END int = 2 // seek relative to the end
+)
+
+// Read reads up to len(b) bytes from the File and stores them in b.
+// It returns the number of bytes read and any error encountered.
+// At end of file, Read returns 0, io.EOF.
+func (f *File) Read(b []byte) (n int, err error) {
+	if err := f.checkValid("read"); err != nil {
+		return 0, err
+	}
+	n, e := f.read(b)
+	return n, f.wrapErr("read", e)
+}
+
+// ReadAt reads len(b) bytes from the File starting at byte offset off.
+// It returns the number of bytes read and the error, if any.
+// ReadAt always returns a non-nil error when n < len(b).
+// At end of file, that error is io.EOF.
+func (f *File) ReadAt(b []byte, off int64) (n int, err error) {
+	/*
+		if err := f.checkValid("read"); err != nil {
+			return 0, err
+		}
+
+		if off < 0 {
+			return 0, &PathError{Op: "readat", Path: f.name, Err: errors.New("negative offset")}
+		}
+
+		for len(b) > 0 {
+			m, e := f.pread(b, off)
+			if e != nil {
+				err = f.wrapErr("read", e)
+				break
+			}
+			n += m
+			b = b[m:]
+			off += int64(m)
+		}
+		return
+	*/
+	panic("todo: os.File.ReadAt")
+}
+
+// ReadFrom implements io.ReaderFrom.
+func (f *File) ReadFrom(r io.Reader) (n int64, err error) {
+	/*
+		if err := f.checkValid("write"); err != nil {
+			return 0, err
+		}
+		n, handled, e := f.readFrom(r)
+		if !handled {
+			return genericReadFrom(f, r) // without wrapping
+		}
+		return n, f.wrapErr("write", e)
+	*/
+	panic("todo: os.File.ReadFrom")
+}
+
+func genericReadFrom(f *File, r io.Reader) (int64, error) {
+	return io.Copy(fileWithoutReadFrom{f}, r)
+}
+
+// fileWithoutReadFrom implements all the methods of *File other
+// than ReadFrom. This is used to permit ReadFrom to call io.Copy
+// without leading to a recursive call to ReadFrom.
+type fileWithoutReadFrom struct {
+	*File
+}
+
+// This ReadFrom method hides the *File ReadFrom method.
+func (fileWithoutReadFrom) ReadFrom(fileWithoutReadFrom) {
+	panic("unreachable")
+}
+
+// Write writes len(b) bytes from b to the File.
+// It returns the number of bytes written and an error, if any.
+// Write returns a non-nil error when n != len(b).
+func (f *File) Write(b []byte) (n int, err error) {
+	if err := f.checkValid("write"); err != nil {
+		return 0, err
+	}
+	n, e := f.write(b)
+
+	// TODO(xsw):
+	// epipecheck(f, e)
+
+	if e != nil {
+		err = f.wrapErr("write", e)
+	} else if n != len(b) {
+		err = io.ErrShortWrite
+	}
+	return n, err
+}
+
+var errWriteAtInAppendMode = errors.New("os: invalid use of WriteAt on file opened with O_APPEND")
+
+// WriteAt writes len(b) bytes to the File starting at byte offset off.
+// It returns the number of bytes written and an error, if any.
+// WriteAt returns a non-nil error when n != len(b).
+//
+// If file was opened with the O_APPEND flag, WriteAt returns an error.
+func (f *File) WriteAt(b []byte, off int64) (n int, err error) {
+	/*
+		if err := f.checkValid("write"); err != nil {
+			return 0, err
+		}
+		if f.appendMode {
+			return 0, errWriteAtInAppendMode
+		}
+
+		if off < 0 {
+			return 0, &PathError{Op: "writeat", Path: f.name, Err: errors.New("negative offset")}
+		}
+
+		for len(b) > 0 {
+			m, e := f.pwrite(b, off)
+			if e != nil {
+				err = f.wrapErr("write", e)
+				break
+			}
+			n += m
+			b = b[m:]
+			off += int64(m)
+		}
+		return
+	*/
+	panic("todo: os.(*File).WriteAt")
+}
+
+// Seek sets the offset for the next Read or Write on file to offset, interpreted
+// according to whence: 0 means relative to the origin of the file, 1 means
+// relative to the current offset, and 2 means relative to the end.
+// It returns the new offset and an error, if any.
+// The behavior of Seek on a file opened with O_APPEND is not specified.
+func (f *File) Seek(offset int64, whence int) (ret int64, err error) {
+	/*
+		if err := f.checkValid("seek"); err != nil {
+			return 0, err
+		}
+		r, e := f.seek(offset, whence)
+		if e == nil && f.dirinfo != nil && r != 0 {
+			e = syscall.EISDIR
+		}
+		if e != nil {
+			return 0, f.wrapErr("seek", e)
+		}
+		return r, nil
+	*/
+	panic("todo: os.(*File).Seek")
+}
+
+// WriteString is like Write, but writes the contents of string s rather than
+// a slice of bytes.
+func (f *File) WriteString(s string) (n int, err error) {
+	/*
+		b := unsafe.Slice(unsafe.StringData(s), len(s))
+		return f.Write(b)
+	*/
+	panic("todo: os.(*File).WriteString")
+}
+
+// setStickyBit adds ModeSticky to the permission bits of path, non atomic.
+func setStickyBit(name string) error {
+	fi, err := Stat(name)
+	if err != nil {
+		return err
+	}
+	return Chmod(name, fi.Mode()|ModeSticky)
+}
+
+// Open opens the named file for reading. If successful, methods on
+// the returned file can be used for reading; the associated file
+// descriptor has mode O_RDONLY.
+// If there is an error, it will be of type *PathError.
+func Open(name string) (*File, error) {
+	return OpenFile(name, O_RDONLY, 0)
+}
+
+// Create creates or truncates the named file. If the file already exists,
+// it is truncated. If the file does not exist, it is created with mode 0666
+// (before umask). If successful, methods on the returned File can
+// be used for I/O; the associated file descriptor has mode O_RDWR.
+// If there is an error, it will be of type *PathError.
+func Create(name string) (*File, error) {
+	return OpenFile(name, O_RDWR|O_CREATE|O_TRUNC, 0666)
+}
+
+// OpenFile is the generalized open call; most users will use Open
+// or Create instead. It opens the named file with specified flag
+// (O_RDONLY etc.). If the file does not exist, and the O_CREATE flag
+// is passed, it is created with mode perm (before umask). If successful,
+// methods on the returned File can be used for I/O.
+// If there is an error, it will be of type *PathError.
+func OpenFile(name string, flag int, perm FileMode) (*File, error) {
+	f, err := openFileNolog(name, flag, perm)
+	if err != nil {
+		return nil, err
+	}
+	f.appendMode = flag&O_APPEND != 0
+
+	return f, nil
+}
+
+/*
+// lstat is overridden in tests.
+var lstat = Lstat
+
+// Many functions in package syscall return a count of -1 instead of 0.
+// Using fixCount(call()) instead of call() corrects the count.
+func fixCount(n int, err error) (int, error) {
+	if n < 0 {
+		n = 0
+	}
+	return n, err
+}
+*/
+
+// TODO(xsw):
+// checkWrapErr is the test hook to enable checking unexpected wrapped errors of poll.ErrFileClosing.
+// It is set to true in the export_test.go for tests (including fuzz tests).
+// var checkWrapErr = false
+
+// wrapErr wraps an error that occurred during an operation on an open file.
+// It passes io.EOF through unchanged, otherwise converts
+// poll.ErrFileClosing to ErrClosed and wraps the error in a PathError.
+func (f *File) wrapErr(op string, err error) error {
+	if err == nil || err == io.EOF {
+		return err
+	}
+	/* TODO(xsw):
+	if err == poll.ErrFileClosing {
+		err = ErrClosed
+	} else if checkWrapErr && errors.Is(err, poll.ErrFileClosing) {
+		panic("unexpected error wrapping poll.ErrFileClosing: " + err.Error())
+	}
+	*/
+	return &PathError{Op: op, Path: f.name, Err: err}
+}
+
+// TempDir returns the default directory to use for temporary files.
+//
+// On Unix systems, it returns $TMPDIR if non-empty, else /tmp.
+// On Windows, it uses GetTempPath, returning the first non-empty
+// value from %TMP%, %TEMP%, %USERPROFILE%, or the Windows directory.
+// On Plan 9, it returns /tmp.
+//
+// The directory is neither guaranteed to exist nor have accessible
+// permissions.
+func TempDir() string {
+	return tempDir()
+}
+
+// Chmod changes the mode of the file to mode.
+// If there is an error, it will be of type *PathError.
+func (f *File) Chmod(mode FileMode) error { return f.chmod(mode) }
+
+// SetDeadline sets the read and write deadlines for a File.
+// It is equivalent to calling both SetReadDeadline and SetWriteDeadline.
+//
+// Only some kinds of files support setting a deadline. Calls to SetDeadline
+// for files that do not support deadlines will return ErrNoDeadline.
+// On most systems ordinary files do not support deadlines, but pipes do.
+//
+// A deadline is an absolute time after which I/O operations fail with an
+// error instead of blocking. The deadline applies to all future and pending
+// I/O, not just the immediately following call to Read or Write.
+// After a deadline has been exceeded, the connection can be refreshed
+// by setting a deadline in the future.
+//
+// If the deadline is exceeded a call to Read or Write or to other I/O
+// methods will return an error that wraps ErrDeadlineExceeded.
+// This can be tested using errors.Is(err, os.ErrDeadlineExceeded).
+// That error implements the Timeout method, and calling the Timeout
+// method will return true, but there are other possible errors for which
+// the Timeout will return true even if the deadline has not been exceeded.
+//
+// An idle timeout can be implemented by repeatedly extending
+// the deadline after successful Read or Write calls.
+//
+// A zero value for t means I/O operations will not time out.
+func (f *File) SetDeadline(t time.Time) error {
+	return f.setDeadline(t)
+}
+
+// SetReadDeadline sets the deadline for future Read calls and any
+// currently-blocked Read call.
+// A zero value for t means Read will not time out.
+// Not all files support setting deadlines; see SetDeadline.
+func (f *File) SetReadDeadline(t time.Time) error {
+	return f.setReadDeadline(t)
+}
+
+// SetWriteDeadline sets the deadline for any future Write calls and any
+// currently-blocked Write call.
+// Even if Write times out, it may return n > 0, indicating that
+// some of the data was successfully written.
+// A zero value for t means Write will not time out.
+// Not all files support setting deadlines; see SetDeadline.
+func (f *File) SetWriteDeadline(t time.Time) error {
+	return f.setWriteDeadline(t)
+}
+
+// SyscallConn returns a raw file.
+// This implements the syscall.Conn interface.
+func (f *File) SyscallConn() (syscall.RawConn, error) {
+	/*
+		if err := f.checkValid("SyscallConn"); err != nil {
+			return nil, err
+		}
+		return newRawConn(f)
+	*/
+	panic("todo: os.(*File).SyscallConn")
+}
+
+/* TODO(xsw):
+// DirFS returns a file system (an fs.FS) for the tree of files rooted at the directory dir.
+//
+// Note that DirFS("/prefix") only guarantees that the Open calls it makes to the
+// operating system will begin with "/prefix": DirFS("/prefix").Open("file") is the
+// same as os.Open("/prefix/file"). So if /prefix/file is a symbolic link pointing outside
+// the /prefix tree, then using DirFS does not stop the access any more than using
+// os.Open does. Additionally, the root of the fs.FS returned for a relative path,
+// DirFS("prefix"), will be affected by later calls to Chdir. DirFS is therefore not
+// a general substitute for a chroot-style security mechanism when the directory tree
+// contains arbitrary content.
+//
+// The directory dir must not be "".
+//
+// The result implements [io/fs.StatFS], [io/fs.ReadFileFS] and
+// [io/fs.ReadDirFS].
+func DirFS(dir string) fs.FS {
+	return dirFS(dir)
+}
+
+// containsAny reports whether any bytes in chars are within s.
+func containsAny(s, chars string) bool {
+	for i := 0; i < len(s); i++ {
+		for j := 0; j < len(chars); j++ {
+			if s[i] == chars[j] {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+type dirFS string
+
+func (dir dirFS) Open(name string) (fs.File, error) {
+	fullname, err := dir.join(name)
+	if err != nil {
+		return nil, &PathError{Op: "stat", Path: name, Err: err}
+	}
+	f, err := Open(fullname)
+	if err != nil {
+		// DirFS takes a string appropriate for GOOS,
+		// while the name argument here is always slash separated.
+		// dir.join will have mixed the two; undo that for
+		// error reporting.
+		err.(*PathError).Path = name
+		return nil, err
+	}
+	return f, nil
+}
+
+// The ReadFile method calls the [ReadFile] function for the file
+// with the given name in the directory. The function provides
+// robust handling for small files and special file systems.
+// Through this method, dirFS implements [io/fs.ReadFileFS].
+func (dir dirFS) ReadFile(name string) ([]byte, error) {
+	fullname, err := dir.join(name)
+	if err != nil {
+		return nil, &PathError{Op: "readfile", Path: name, Err: err}
+	}
+	return ReadFile(fullname)
+}
+
+// ReadDir reads the named directory, returning all its directory entries sorted
+// by filename. Through this method, dirFS implements [io/fs.ReadDirFS].
+func (dir dirFS) ReadDir(name string) ([]DirEntry, error) {
+	fullname, err := dir.join(name)
+	if err != nil {
+		return nil, &PathError{Op: "readdir", Path: name, Err: err}
+	}
+	return ReadDir(fullname)
+}
+
+func (dir dirFS) Stat(name string) (fs.FileInfo, error) {
+	fullname, err := dir.join(name)
+	if err != nil {
+		return nil, &PathError{Op: "stat", Path: name, Err: err}
+	}
+	f, err := Stat(fullname)
+	if err != nil {
+		// See comment in dirFS.Open.
+		err.(*PathError).Path = name
+		return nil, err
+	}
+	return f, nil
+}
+
+// join returns the path for name in dir.
+func (dir dirFS) join(name string) (string, error) {
+	if dir == "" {
+		return "", errors.New("os: DirFS with empty root")
+	}
+	if !fs.ValidPath(name) {
+		return "", ErrInvalid
+	}
+	name, err := safefilepath.FromFS(name)
+	if err != nil {
+		return "", ErrInvalid
+	}
+	if IsPathSeparator(dir[len(dir)-1]) {
+		return string(dir) + name, nil
+	}
+	return string(dir) + string(PathSeparator) + name, nil
+}
+*/
+
+// ReadFile reads the named file and returns the contents.
+// A successful call returns err == nil, not err == EOF.
+// Because ReadFile reads the whole file, it does not treat an EOF from Read
+// as an error to be reported.
+func ReadFile(name string) ([]byte, error) {
+	f, err := Open(name)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	var size int
+	if info, err := f.Stat(); err == nil {
+		size64 := info.Size()
+		if int64(int(size64)) == size64 {
+			size = int(size64)
+		}
+	}
+	size++ // one byte for final read at EOF
+
+	// If a file claims a small size, read at least 512 bytes.
+	// In particular, files in Linux's /proc claim size 0 but
+	// then do not work right if read in small pieces,
+	// so an initial read of 1 byte would not work correctly.
+	if size < 512 {
+		size = 512
+	}
+
+	data := make([]byte, 0, size)
+	for {
+		if len(data) >= cap(data) {
+			d := append(data[:cap(data)], 0)
+			data = d[:len(data)]
+		}
+		n, err := f.Read(data[len(data):cap(data)])
+		data = data[:len(data)+n]
+		if err != nil {
+			if err == io.EOF {
+				err = nil
+			}
+			return data, err
+		}
+	}
+}
+
+// WriteFile writes data to the named file, creating it if necessary.
+// If the file does not exist, WriteFile creates it with permissions perm (before umask);
+// otherwise WriteFile truncates it before writing, without changing permissions.
+// Since WriteFile requires multiple system calls to complete, a failure mid-operation
+// can leave the file in a partially written state.
+func WriteFile(name string, data []byte, perm FileMode) error {
+	f, err := OpenFile(name, O_WRONLY|O_CREATE|O_TRUNC, perm)
+	if err != nil {
+		return err
+	}
+	_, err = f.Write(data)
+	if err1 := f.Close(); err1 != nil && err == nil {
+		err = err1
+	}
+	return err
+}

compiler/internal/lib/os/file_posix.go

@@ -0,0 +1,240 @@
+// Copyright 2009 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 unix || (js && wasm) || wasip1 || windows
+
+package os
+
+import (
+	"syscall"
+	"time"
+)
+
+// Close closes the File, rendering it unusable for I/O.
+// On files that support SetDeadline, any pending I/O operations will
+// be canceled and return immediately with an ErrClosed error.
+// Close will return an error if it has already been called.
+func (f *File) Close() error {
+	if f == nil {
+		return ErrInvalid
+	}
+	return f.close()
+}
+
+// pread reads len(b) bytes from the File starting at byte offset off.
+// It returns the number of bytes read and the error, if any.
+// EOF is signaled by a zero count with err set to nil.
+func (f *File) pread(b []byte, off int64) (n int, err error) {
+	/*
+		n, err = f.pfd.Pread(b, off)
+		runtime.KeepAlive(f)
+		return n, err
+	*/
+	panic("todo: os.(*File).pread")
+}
+
+// pwrite writes len(b) bytes to the File starting at byte offset off.
+// It returns the number of bytes written and an error, if any.
+func (f *File) pwrite(b []byte, off int64) (n int, err error) {
+	/*
+		n, err = f.pfd.Pwrite(b, off)
+		runtime.KeepAlive(f)
+		return n, err
+	*/
+	panic("todo: os.(*File).pwrite")
+}
+
+// syscallMode returns the syscall-specific mode bits from Go's portable mode bits.
+func syscallMode(i FileMode) (o uint32) {
+	o |= uint32(i.Perm())
+	if i&ModeSetuid != 0 {
+		o |= syscall.S_ISUID
+	}
+	if i&ModeSetgid != 0 {
+		o |= syscall.S_ISGID
+	}
+	if i&ModeSticky != 0 {
+		o |= syscall.S_ISVTX
+	}
+	// No mapping for Go's ModeTemporary (plan9 only).
+	return
+}
+
+/* TODO(xsw):
+// See docs in file.go:Chmod.
+func chmod(name string, mode FileMode) error {
+	longName := fixLongPath(name)
+	e := ignoringEINTR(func() error {
+		return syscall.Chmod(longName, syscallMode(mode))
+	})
+	if e != nil {
+		return &PathError{Op: "chmod", Path: name, Err: e}
+	}
+	return nil
+}
+*/
+
+// See docs in file.go:(*File).Chmod.
+func (f *File) chmod(mode FileMode) error {
+	/*
+		if err := f.checkValid("chmod"); err != nil {
+			return err
+		}
+		if e := f.pfd.Fchmod(syscallMode(mode)); e != nil {
+			return f.wrapErr("chmod", e)
+		}
+		return nil
+	*/
+	panic("todo: os.(*File).chmod")
+}
+
+// Chown changes the numeric uid and gid of the named file.
+// If there is an error, it will be of type *PathError.
+//
+// On Windows, it always returns the syscall.EWINDOWS error, wrapped
+// in *PathError.
+func (f *File) Chown(uid, gid int) error {
+	/*
+		if err := f.checkValid("chown"); err != nil {
+			return err
+		}
+		if e := f.pfd.Fchown(uid, gid); e != nil {
+			return f.wrapErr("chown", e)
+		}
+		return nil
+	*/
+	panic("todo: os.(*File).Chown")
+}
+
+// Truncate changes the size of the file.
+// It does not change the I/O offset.
+// If there is an error, it will be of type *PathError.
+func (f *File) Truncate(size int64) error {
+	/*
+		if err := f.checkValid("truncate"); err != nil {
+			return err
+		}
+		if e := f.pfd.Ftruncate(size); e != nil {
+			return f.wrapErr("truncate", e)
+		}
+		return nil
+	*/
+	panic("todo: os.(*File).Truncate")
+}
+
+// Sync commits the current contents of the file to stable storage.
+// Typically, this means flushing the file system's in-memory copy
+// of recently written data to disk.
+func (f *File) Sync() error {
+	/*
+		if err := f.checkValid("sync"); err != nil {
+			return err
+		}
+		if e := f.pfd.Fsync(); e != nil {
+			return f.wrapErr("sync", e)
+		}
+		return nil
+	*/
+	panic("todo: os.(*File).Sync")
+}
+
+/*
+// Chtimes changes the access and modification times of the named
+// file, similar to the Unix utime() or utimes() functions.
+// A zero time.Time value will leave the corresponding file time unchanged.
+//
+// The underlying filesystem may truncate or round the values to a
+// less precise time unit.
+// If there is an error, it will be of type *PathError.
+func Chtimes(name string, atime time.Time, mtime time.Time) error {
+	var utimes [2]syscall.Timespec
+	set := func(i int, t time.Time) {
+		if t.IsZero() {
+			utimes[i] = syscall.Timespec{Sec: _UTIME_OMIT, Nsec: _UTIME_OMIT}
+		} else {
+			utimes[i] = syscall.NsecToTimespec(t.UnixNano())
+		}
+	}
+	set(0, atime)
+	set(1, mtime)
+	if e := syscall.UtimesNano(fixLongPath(name), utimes[0:]); e != nil {
+		return &PathError{Op: "chtimes", Path: name, Err: e}
+	}
+	return nil
+}
+*/
+
+// Chdir changes the current working directory to the file,
+// which must be a directory.
+// If there is an error, it will be of type *PathError.
+func (f *File) Chdir() error {
+	/*
+		if err := f.checkValid("chdir"); err != nil {
+			return err
+		}
+		if e := f.pfd.Fchdir(); e != nil {
+			return f.wrapErr("chdir", e)
+		}
+		return nil
+	*/
+	panic("todo: os.(*File).Chdir")
+}
+
+// setDeadline sets the read and write deadline.
+func (f *File) setDeadline(t time.Time) error {
+	/*
+		if err := f.checkValid("SetDeadline"); err != nil {
+			return err
+		}
+		return f.pfd.SetDeadline(t)
+	*/
+	panic("todo: os.(*File).setDeadline")
+}
+
+// setReadDeadline sets the read deadline.
+func (f *File) setReadDeadline(t time.Time) error {
+	/*
+		if err := f.checkValid("SetReadDeadline"); err != nil {
+			return err
+		}
+		return f.pfd.SetReadDeadline(t)
+	*/
+	panic("todo: os.(*File).setReadDeadline")
+}
+
+// setWriteDeadline sets the write deadline.
+func (f *File) setWriteDeadline(t time.Time) error {
+	/*
+		if err := f.checkValid("SetWriteDeadline"); err != nil {
+			return err
+		}
+		return f.pfd.SetWriteDeadline(t)
+	*/
+	panic("todo: os.(*File).setWriteDeadline")
+}
+
+// checkValid checks whether f is valid for use.
+// If not, it returns an appropriate error, perhaps incorporating the operation name op.
+func (f *File) checkValid(op string) error {
+	if f == nil {
+		return ErrInvalid
+	}
+	return nil
+}
+
+// ignoringEINTR makes a function call and repeats it if it returns an
+// EINTR error. This appears to be required even though we install all
+// signal handlers with SA_RESTART: see #22838, #38033, #38836, #40846.
+// Also #20400 and #36644 are issues in which a signal handler is
+// installed without setting SA_RESTART. None of these are the common case,
+// but there are enough of them that it seems that we can't avoid
+// an EINTR loop.
+func ignoringEINTR(fn func() error) error {
+	for {
+		err := fn()
+		if err != syscall.EINTR {
+			return err
+		}
+	}
+}

compiler/internal/lib/os/file_unix.go

@@ -0,0 +1,334 @@
+// Copyright 2009 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 unix || (js && wasm) || wasip1
+
+package os
+
+import (
+	"runtime"
+	"syscall"
+
+	"github.com/goplus/llgo/compiler/internal/lib/internal/syscall/unix"
+)
+
+// Fd returns the integer Unix file descriptor referencing the open file.
+// If f is closed, the file descriptor becomes invalid.
+// If f is garbage collected, a finalizer may close the file descriptor,
+// making it invalid; see runtime.SetFinalizer for more information on when
+// a finalizer might be run. On Unix systems this will cause the SetDeadline
+// methods to stop working.
+// Because file descriptors can be reused, the returned file descriptor may
+// only be closed through the Close method of f, or by its finalizer during
+// garbage collection. Otherwise, during garbage collection the finalizer
+// may close an unrelated file descriptor with the same (reused) number.
+//
+// As an alternative, see the f.SyscallConn method.
+func (f *File) Fd() uintptr {
+	if f == nil {
+		return ^(uintptr(0))
+	}
+
+	return f.fd
+}
+
+func NewFile(fd uintptr, name string) *File {
+	return &File{fd: fd, name: name}
+}
+
+/* TODO(xsw):
+// NewFile returns a new File with the given file descriptor and
+// name. The returned value will be nil if fd is not a valid file
+// descriptor. On Unix systems, if the file descriptor is in
+// non-blocking mode, NewFile will attempt to return a pollable File
+// (one for which the SetDeadline methods work).
+//
+// After passing it to NewFile, fd may become invalid under the same
+// conditions described in the comments of the Fd method, and the same
+// constraints apply.
+func NewFile(fd uintptr, name string) *File {
+	fdi := int(fd)
+	if fdi < 0 {
+		return nil
+	}
+
+	kind := kindNewFile
+	appendMode := false
+	if flags, err := unix.Fcntl(fdi, syscall.F_GETFL, 0); err == nil {
+		if unix.HasNonblockFlag(flags) {
+			kind = kindNonBlock
+		}
+		appendMode = flags&syscall.O_APPEND != 0
+	}
+	f := newFile(fdi, name, kind)
+	f.appendMode = appendMode
+	return f
+}
+
+// net_newUnixFile is a hidden entry point called by net.conn.File.
+// This is used so that a nonblocking network connection will become
+// blocking if code calls the Fd method. We don't want that for direct
+// calls to NewFile: passing a nonblocking descriptor to NewFile should
+// remain nonblocking if you get it back using Fd. But for net.conn.File
+// the call to NewFile is hidden from the user. Historically in that case
+// the Fd method has returned a blocking descriptor, and we want to
+// retain that behavior because existing code expects it and depends on it.
+//
+//-go:linkname net_newUnixFile net.newUnixFile
+func net_newUnixFile(fd int, name string) *File {
+	if fd < 0 {
+		panic("invalid FD")
+	}
+
+	f := newFile(fd, name, kindNonBlock)
+	f.nonblock = true // tell Fd to return blocking descriptor
+	return f
+}
+*/
+
+// newFileKind describes the kind of file to newFile.
+type newFileKind int
+
+const (
+	// kindNewFile means that the descriptor was passed to us via NewFile.
+	kindNewFile newFileKind = iota
+	// kindOpenFile means that the descriptor was opened using
+	// Open, Create, or OpenFile (without O_NONBLOCK).
+	kindOpenFile
+	// kindPipe means that the descriptor was opened using Pipe.
+	kindPipe
+	// kindNonBlock means that the descriptor is already in
+	// non-blocking mode.
+	kindNonBlock
+	// kindNoPoll means that we should not put the descriptor into
+	// non-blocking mode, because we know it is not a pipe or FIFO.
+	// Used by openFdAt for directories.
+	kindNoPoll
+)
+
+// newFile is like NewFile, but if called from OpenFile or Pipe
+// (as passed in the kind parameter) it tries to add the file to
+// the runtime poller.
+func newFile(fd int, name string, kind newFileKind) *File {
+	f := &File{
+		fd:          uintptr(fd),
+		name:        name,
+		stdoutOrErr: fd == 1 || fd == 2,
+	}
+
+	/* TODO(xsw):
+	pollable := kind == kindOpenFile || kind == kindPipe || kind == kindNonBlock
+
+	// If the caller passed a non-blocking filedes (kindNonBlock),
+	// we assume they know what they are doing so we allow it to be
+	// used with kqueue.
+	if kind == kindOpenFile {
+		switch runtime.GOOS {
+		case "darwin", "ios", "dragonfly", "freebsd", "netbsd", "openbsd":
+			var st syscall.Stat_t
+			err := ignoringEINTR(func() error {
+				return syscall.Fstat(fd, &st)
+			})
+			typ := st.Mode & syscall.S_IFMT
+			// Don't try to use kqueue with regular files on *BSDs.
+			// On FreeBSD a regular file is always
+			// reported as ready for writing.
+			// On Dragonfly, NetBSD and OpenBSD the fd is signaled
+			// only once as ready (both read and write).
+			// Issue 19093.
+			// Also don't add directories to the netpoller.
+			if err == nil && (typ == syscall.S_IFREG || typ == syscall.S_IFDIR) {
+				pollable = false
+			}
+
+			// In addition to the behavior described above for regular files,
+			// on Darwin, kqueue does not work properly with fifos:
+			// closing the last writer does not cause a kqueue event
+			// for any readers. See issue #24164.
+			if (runtime.GOOS == "darwin" || runtime.GOOS == "ios") && typ == syscall.S_IFIFO {
+				pollable = false
+			}
+		}
+	}
+
+	clearNonBlock := false
+	if pollable {
+		if kind == kindNonBlock {
+			// The descriptor is already in non-blocking mode.
+			// We only set f.nonblock if we put the file into
+			// non-blocking mode.
+		} else if err := syscall.SetNonblock(fd, true); err == nil {
+			f.nonblock = true
+			clearNonBlock = true
+		} else {
+			pollable = false
+		}
+	}
+
+	// An error here indicates a failure to register
+	// with the netpoll system. That can happen for
+	// a file descriptor that is not supported by
+	// epoll/kqueue; for example, disk files on
+	// Linux systems. We assume that any real error
+	// will show up in later I/O.
+	// We do restore the blocking behavior if it was set by us.
+	if pollErr := f.pfd.Init("file", pollable); pollErr != nil && clearNonBlock {
+		if err := syscall.SetNonblock(fd, false); err == nil {
+			f.nonblock = false
+		}
+	}
+
+	runtime.SetFinalizer(f.file, (*file).close)
+	*/
+	return f
+}
+
+// TODO(xsw):
+// func sigpipe() // implemented in package runtime
+
+// epipecheck raises SIGPIPE if we get an EPIPE error on standard
+// output or standard error. See the SIGPIPE docs in os/signal, and
+// issue 11845.
+func epipecheck(file *File, e error) {
+	/* TODO(xsw):
+	if e == syscall.EPIPE && file.stdoutOrErr {
+		sigpipe()
+	}
+	*/
+	panic("todo: os.epipecheck")
+}
+
+// DevNull is the name of the operating system's “null device.”
+// On Unix-like systems, it is "/dev/null"; on Windows, "NUL".
+const DevNull = "/dev/null"
+
+// openFileNolog is the Unix implementation of OpenFile.
+// Changes here should be reflected in openFdAt, if relevant.
+func openFileNolog(name string, flag int, perm FileMode) (*File, error) {
+	setSticky := false
+	if !supportsCreateWithStickyBit && flag&O_CREATE != 0 && perm&ModeSticky != 0 {
+		if _, err := Stat(name); IsNotExist(err) {
+			setSticky = true
+		}
+	}
+
+	var r int
+	for {
+		var e error
+		r, e = syscall.Open(name, flag|syscall.O_CLOEXEC, syscallMode(perm))
+		if e == nil {
+			break
+		}
+
+		// We have to check EINTR here, per issues 11180 and 39237.
+		if e == syscall.EINTR {
+			continue
+		}
+
+		return nil, &PathError{Op: "open", Path: name, Err: e}
+	}
+
+	// open(2) itself won't handle the sticky bit on *BSD and Solaris
+	if setSticky {
+		setStickyBit(name)
+	}
+
+	// There's a race here with fork/exec, which we are
+	// content to live with. See ../syscall/exec_unix.go.
+	if !supportsCloseOnExec {
+		syscall.CloseOnExec(r)
+	}
+
+	kind := kindOpenFile
+	if unix.HasNonblockFlag(flag) {
+		kind = kindNonBlock
+		panic("todo: os.openFileNolog: unix.HasNonblockFlag")
+	}
+
+	f := newFile(r, name, kind)
+	return f, nil
+}
+
+func (file *File) close() error {
+	return syscall.Close(int(file.fd))
+	/* TODO(xsw):
+	if file.dirinfo != nil {
+		file.dirinfo.close()
+		file.dirinfo = nil
+	}
+	var err error
+	if e := file.pfd.Close(); e != nil {
+		if e == poll.ErrFileClosing {
+			e = ErrClosed
+		}
+		err = &PathError{Op: "close", Path: file.name, Err: e}
+	}
+
+	// no need for a finalizer anymore
+	runtime.SetFinalizer(file, nil)
+	return err
+	*/
+}
+
+func tempDir() string {
+	dir := Getenv("TMPDIR")
+	if dir == "" {
+		if runtime.GOOS == "android" {
+			dir = "/data/local/tmp"
+		} else {
+			dir = "/tmp"
+		}
+	}
+	return dir
+}
+
+type unixDirent struct {
+	parent string
+	name   string
+	typ    FileMode
+	info   FileInfo
+}
+
+func (d *unixDirent) Name() string   { return d.name }
+func (d *unixDirent) IsDir() bool    { return d.typ.IsDir() }
+func (d *unixDirent) Type() FileMode { return d.typ }
+
+func (d *unixDirent) Info() (FileInfo, error) {
+	/* TODO(xsw):
+	if d.info != nil {
+		return d.info, nil
+	}
+	return lstat(d.parent + "/" + d.name)
+	*/
+	panic("todo: os.unixDirent.Info")
+}
+
+func (d *unixDirent) String() string {
+	/* TODO(xsw):
+	return fs.FormatDirEntry(d)
+	*/
+	panic("todo: os.unixDirent.String")
+}
+
+/* TODO(xsw):
+func newUnixDirent(parent, name string, typ FileMode) (DirEntry, error) {
+	ude := &unixDirent{
+		parent: parent,
+		name:   name,
+		typ:    typ,
+	}
+	if typ != ^FileMode(0) && !testingForceReadDirLstat {
+		return ude, nil
+	}
+
+	info, err := lstat(parent + "/" + name)
+	if err != nil {
+		return nil, err
+	}
+
+	ude.typ = info.Mode().Type()
+	ude.info = info
+	return ude, nil
+}
+*/

compiler/internal/lib/os/os.go

@@ -0,0 +1,464 @@
+/*
+ * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package os
+
+// llgo:skipall
+import (
+	"errors"
+	"runtime"
+	"syscall"
+	_ "unsafe"
+
+	"github.com/goplus/llgo/c"
+	"github.com/goplus/llgo/c/os"
+)
+
+const (
+	LLGoPackage = true
+)
+
+// LinkError records an error during a link or symlink or rename
+// system call and the paths that caused it.
+type LinkError struct {
+	Op  string
+	Old string
+	New string
+	Err error
+}
+
+func (e *LinkError) Error() string {
+	return e.Op + " " + e.Old + " " + e.New + ": " + e.Err.Error()
+}
+
+func (e *LinkError) Unwrap() error {
+	return e.Err
+}
+
+func toPathErr(op, path string, errno c.Int) error {
+	return &PathError{Op: op, Path: path, Err: syscall.Errno(errno)}
+}
+
+func Chdir(dir string) error {
+	ret := os.Chdir(c.AllocaCStr(dir))
+	if ret == 0 {
+		return nil
+	}
+	return toPathErr("chdir", dir, ret)
+}
+
+/* TODO(xsw):
+// Chdir changes the current working directory to the named directory.
+// If there is an error, it will be of type *PathError.
+func Chdir(dir string) error {
+	if e := syscall.Chdir(dir); e != nil {
+		testlog.Open(dir) // observe likely non-existent directory
+		return &PathError{Op: "chdir", Path: dir, Err: e}
+	}
+	if log := testlog.Logger(); log != nil {
+		wd, err := Getwd()
+		if err == nil {
+			log.Chdir(wd)
+		}
+	}
+	return nil
+}
+*/
+
+func Chmod(name string, mode FileMode) error {
+	ret := os.Chmod(c.AllocaCStr(name), os.ModeT(syscallMode(mode)))
+	if ret == 0 {
+		return nil
+	}
+	return toPathErr("chmod", name, ret)
+}
+
+/* TODO(xsw):
+// Chmod changes the mode of the named file to mode.
+// If the file is a symbolic link, it changes the mode of the link's target.
+// If there is an error, it will be of type *PathError.
+//
+// A different subset of the mode bits are used, depending on the
+// operating system.
+//
+// On Unix, the mode's permission bits, ModeSetuid, ModeSetgid, and
+// ModeSticky are used.
+//
+// On Windows, only the 0200 bit (owner writable) of mode is used; it
+// controls whether the file's read-only attribute is set or cleared.
+// The other bits are currently unused. For compatibility with Go 1.12
+// and earlier, use a non-zero mode. Use mode 0400 for a read-only
+// file and 0600 for a readable+writable file.
+//
+// On Plan 9, the mode's permission bits, ModeAppend, ModeExclusive,
+// and ModeTemporary are used.
+func Chmod(name string, mode FileMode) error { return chmod(name, mode) }
+*/
+
+func Chown(name string, uid, gid int) error {
+	ret := os.Chown(c.AllocaCStr(name), os.UidT(uid), os.GidT(gid))
+	if ret == 0 {
+		return nil
+	}
+	return toPathErr("chown", name, ret)
+}
+
+/* TODO(xsw):
+// Chown changes the numeric uid and gid of the named file.
+// If the file is a symbolic link, it changes the uid and gid of the link's target.
+// A uid or gid of -1 means to not change that value.
+// If there is an error, it will be of type *PathError.
+//
+// On Windows or Plan 9, Chown always returns the syscall.EWINDOWS or
+// EPLAN9 error, wrapped in *PathError.
+func Chown(name string, uid, gid int) error {
+	e := ignoringEINTR(func() error {
+		return syscall.Chown(name, uid, gid)
+	})
+	if e != nil {
+		return &PathError{Op: "chown", Path: name, Err: e}
+	}
+	return nil
+}
+*/
+
+// TODO(xsw):
+// func Chtimes(name string, atime time.Time, mtime time.Time) error
+
+//go:linkname Clearenv C.clearenv
+func Clearenv()
+
+// TODO(xsw):
+// func DirFS(dir string) fs.FS
+
+// func Executable() (string, error)
+
+// TODO(xsw):
+// func Expand(s string, mapping func(string) string) string
+// func ExpandEnv(s string) string
+
+func Getegid() int {
+	return int(os.Getegid())
+}
+
+func Geteuid() int {
+	return int(os.Geteuid())
+}
+
+func Getgid() int {
+	return int(os.Getgid())
+}
+
+// TODO(xsw):
+// func Getgroups() ([]int, error)
+// func Getpagesize() int
+
+func Getpid() int {
+	return int(os.Getpid())
+}
+
+func Getppid() int {
+	return int(os.Getppid())
+}
+
+func Getuid() int {
+	return int(os.Getuid())
+}
+
+func Getwd() (dir string, err error) {
+	wd := os.Getcwd(c.Alloca(os.PATH_MAX), os.PATH_MAX)
+	if wd != nil {
+		return c.GoString(wd), nil
+	}
+	return "", syscall.Errno(os.Errno())
+}
+
+// TODO(xsw):
+// func Hostname() (name string, err error)
+// func IsExist(err error) bool
+// func IsNotExist(err error) bool
+// func IsPermission(err error) bool
+// func IsTimeout(err error) bool
+
+func Lchown(name string, uid, gid int) error {
+	ret := os.Lchown(c.AllocaCStr(name), os.UidT(uid), os.GidT(gid))
+	if ret == 0 {
+		return nil
+	}
+	return toPathErr("lchown", name, ret)
+}
+
+/* TODO(xsw):
+// Lchown changes the numeric uid and gid of the named file.
+// If the file is a symbolic link, it changes the uid and gid of the link itself.
+// If there is an error, it will be of type *PathError.
+//
+// On Windows, it always returns the syscall.EWINDOWS error, wrapped
+// in *PathError.
+func Lchown(name string, uid, gid int) error {
+	e := ignoringEINTR(func() error {
+		return syscall.Lchown(name, uid, gid)
+	})
+	if e != nil {
+		return &PathError{Op: "lchown", Path: name, Err: e}
+	}
+	return nil
+}
+*/
+
+func Link(oldname, newname string) error {
+	ret := os.Link(c.AllocaCStr(oldname), c.AllocaCStr(newname))
+	if ret == 0 {
+		return nil
+	}
+	return &LinkError{"link", oldname, newname, syscall.Errno(ret)}
+}
+
+// TODO(xsw):
+// func LookupEnv(key string) (string, bool)
+
+func Mkdir(name string, perm FileMode) error {
+	ret := os.Mkdir(c.AllocaCStr(name), os.ModeT(syscallMode(perm)))
+	if ret == 0 {
+		return nil
+	}
+	return toPathErr("mkdir", name, ret)
+}
+
+/* TODO(xsw):
+// Mkdir creates a new directory with the specified name and permission
+// bits (before umask).
+// If there is an error, it will be of type *PathError.
+func Mkdir(name string, perm FileMode) error {
+	longName := fixLongPath(name)
+	e := ignoringEINTR(func() error {
+		return syscall.Mkdir(longName, syscallMode(perm))
+	})
+
+	if e != nil {
+		return &PathError{Op: "mkdir", Path: name, Err: e}
+	}
+
+	// mkdir(2) itself won't handle the sticky bit on *BSD and Solaris
+	if !supportsCreateWithStickyBit && perm&ModeSticky != 0 {
+		e = setStickyBit(name)
+
+		if e != nil {
+			Remove(name)
+			return e
+		}
+	}
+
+	return nil
+}
+*/
+
+// TODO(xsw):
+// func NewSyscallError(syscall string, err error) error
+
+// func ReadFile(name string) ([]byte, error)
+
+func Readlink(name string) (string, error) {
+	ptr := c.Alloca(os.PATH_MAX)
+	ret := os.Readlink(c.AllocaCStr(name), ptr, os.PATH_MAX)
+	if ret < os.PATH_MAX {
+		return c.GoString((*c.Char)(ptr), ret), nil
+	}
+	panic("todo: buffer too small")
+}
+
+func Remove(name string) error {
+	ret := os.Remove(c.AllocaCStr(name))
+	if ret == 0 {
+		return nil
+	}
+	return toPathErr("remove", name, ret)
+}
+
+// TODO(xsw):
+// func RemoveAll(path string) error
+
+func Rename(oldpath, newpath string) error {
+	ret := os.Rename(c.AllocaCStr(oldpath), c.AllocaCStr(newpath))
+	if ret == 0 {
+		return nil
+	}
+	return &LinkError{"rename", oldpath, newpath, syscall.Errno(ret)}
+}
+
+/* TODO(xsw):
+// Rename renames (moves) oldpath to newpath.
+// If newpath already exists and is not a directory, Rename replaces it.
+// OS-specific restrictions may apply when oldpath and newpath are in different directories.
+// Even within the same directory, on non-Unix platforms Rename is not an atomic operation.
+// If there is an error, it will be of type *LinkError.
+func Rename(oldpath, newpath string) error {
+	return rename(oldpath, newpath)
+}
+*/
+
+// TODO(xsw):
+// func SameFile(fi1, fi2 FileInfo) bool
+
+func Symlink(oldname, newname string) error {
+	ret := os.Symlink(c.AllocaCStr(oldname), c.AllocaCStr(newname))
+	if ret == 0 {
+		return nil
+	}
+	return &LinkError{"symlink", oldname, newname, syscall.Errno(ret)}
+}
+
+func Truncate(name string, size int64) error {
+	ret := os.Truncate(c.AllocaCStr(name), os.OffT(size))
+	if ret == 0 {
+		return nil
+	}
+	return toPathErr("truncate", name, ret)
+}
+
+// UserCacheDir returns the default root directory to use for user-specific
+// cached data. Users should create their own application-specific subdirectory
+// within this one and use that.
+//
+// On Unix systems, it returns $XDG_CACHE_HOME as specified by
+// https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html if
+// non-empty, else $HOME/.cache.
+// On Darwin, it returns $HOME/Library/Caches.
+// On Windows, it returns %LocalAppData%.
+// On Plan 9, it returns $home/lib/cache.
+//
+// If the location cannot be determined (for example, $HOME is not defined),
+// then it will return an error.
+func UserCacheDir() (string, error) {
+	var dir string
+
+	switch runtime.GOOS {
+	case "windows":
+		dir = Getenv("LocalAppData")
+		if dir == "" {
+			return "", errors.New("%LocalAppData% is not defined")
+		}
+
+	case "darwin", "ios":
+		dir = Getenv("HOME")
+		if dir == "" {
+			return "", errors.New("$HOME is not defined")
+		}
+		dir += "/Library/Caches"
+
+	case "plan9":
+		dir = Getenv("home")
+		if dir == "" {
+			return "", errors.New("$home is not defined")
+		}
+		dir += "/lib/cache"
+
+	default: // Unix
+		dir = Getenv("XDG_CACHE_HOME")
+		if dir == "" {
+			dir = Getenv("HOME")
+			if dir == "" {
+				return "", errors.New("neither $XDG_CACHE_HOME nor $HOME are defined")
+			}
+			dir += "/.cache"
+		}
+	}
+
+	return dir, nil
+}
+
+// UserConfigDir returns the default root directory to use for user-specific
+// configuration data. Users should create their own application-specific
+// subdirectory within this one and use that.
+//
+// On Unix systems, it returns $XDG_CONFIG_HOME as specified by
+// https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html if
+// non-empty, else $HOME/.config.
+// On Darwin, it returns $HOME/Library/Application Support.
+// On Windows, it returns %AppData%.
+// On Plan 9, it returns $home/lib.
+//
+// If the location cannot be determined (for example, $HOME is not defined),
+// then it will return an error.
+func UserConfigDir() (string, error) {
+	var dir string
+
+	switch runtime.GOOS {
+	case "windows":
+		dir = Getenv("AppData")
+		if dir == "" {
+			return "", errors.New("%AppData% is not defined")
+		}
+
+	case "darwin", "ios":
+		dir = Getenv("HOME")
+		if dir == "" {
+			return "", errors.New("$HOME is not defined")
+		}
+		dir += "/Library/Application Support"
+
+	case "plan9":
+		dir = Getenv("home")
+		if dir == "" {
+			return "", errors.New("$home is not defined")
+		}
+		dir += "/lib"
+
+	default: // Unix
+		dir = Getenv("XDG_CONFIG_HOME")
+		if dir == "" {
+			dir = Getenv("HOME")
+			if dir == "" {
+				return "", errors.New("neither $XDG_CONFIG_HOME nor $HOME are defined")
+			}
+			dir += "/.config"
+		}
+	}
+
+	return dir, nil
+}
+
+// UserHomeDir returns the current user's home directory.
+//
+// On Unix, including macOS, it returns the $HOME environment variable.
+// On Windows, it returns %USERPROFILE%.
+// On Plan 9, it returns the $home environment variable.
+//
+// If the expected variable is not set in the environment, UserHomeDir
+// returns either a platform-specific default value or a non-nil error.
+func UserHomeDir() (string, error) {
+	env, enverr := "HOME", "$HOME"
+	switch runtime.GOOS {
+	case "windows":
+		env, enverr = "USERPROFILE", "%userprofile%"
+	case "plan9":
+		env, enverr = "home", "$home"
+	}
+	if v := Getenv(env); v != "" {
+		return v, nil
+	}
+	// On some geese the home directory is not always defined.
+	switch runtime.GOOS {
+	case "android":
+		return "/sdcard", nil
+	case "ios":
+		return "/", nil
+	}
+	return "", errors.New(enverr + " is not defined")
+}
+
+// TODO(xsw):
+// func WriteFile(name string, data []byte, perm FileMode) error

compiler/internal/lib/os/path.go

@@ -0,0 +1,55 @@
+package os
+
+import (
+	"syscall"
+)
+
+// MkdirAll creates a directory named path,
+// along with any necessary parents, and returns nil,
+// or else returns an error.
+// The permission bits perm (before umask) are used for all
+// directories that MkdirAll creates.
+// If path is already a directory, MkdirAll does nothing
+// and returns nil.
+func MkdirAll(path string, perm FileMode) error {
+	// Fast path: if we can tell whether path is a directory or file, stop with success or error.
+	dir, err := Stat(path)
+	if err == nil {
+		if dir.IsDir() {
+			return nil
+		}
+		return &PathError{Op: "mkdir", Path: path, Err: syscall.ENOTDIR}
+	}
+
+	// Slow path: make sure parent exists and then call Mkdir for path.
+	i := len(path)
+	for i > 0 && IsPathSeparator(path[i-1]) { // Skip trailing path separator.
+		i--
+	}
+
+	j := i
+	for j > 0 && !IsPathSeparator(path[j-1]) { // Scan backward over element.
+		j--
+	}
+
+	if j > 1 {
+		// Create parent.
+		err = MkdirAll(fixRootDirectory(path[:j-1]), perm)
+		if err != nil {
+			return err
+		}
+	}
+
+	// Parent now exists; invoke Mkdir and use its result.
+	err = Mkdir(path, perm)
+	if err != nil {
+		// Handle arguments like "foo/." by
+		// double-checking that directory doesn't exist.
+		dir, err1 := Lstat(path)
+		if err1 == nil && dir.IsDir() {
+			return nil
+		}
+		return err
+	}
+	return nil
+}

compiler/internal/lib/os/path_plan9.go

@@ -0,0 +1,19 @@
+// Copyright 2011 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 os
+
+const (
+	PathSeparator     = '/'    // OS-specific path separator
+	PathListSeparator = '\000' // OS-specific path list separator
+)
+
+// IsPathSeparator reports whether c is a directory separator character.
+func IsPathSeparator(c uint8) bool {
+	return PathSeparator == c
+}
+
+func fixRootDirectory(p string) string {
+	return p
+}

compiler/internal/lib/os/path_unix.go

@@ -0,0 +1,75 @@
+// Copyright 2011 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 unix || (js && wasm) || wasip1
+
+package os
+
+const (
+	PathSeparator     = '/' // OS-specific path separator
+	PathListSeparator = ':' // OS-specific path list separator
+)
+
+// IsPathSeparator reports whether c is a directory separator character.
+func IsPathSeparator(c uint8) bool {
+	return PathSeparator == c
+}
+
+// basename removes trailing slashes and the leading directory name from path name.
+func basename(name string) string {
+	i := len(name) - 1
+	// Remove trailing slashes
+	for ; i > 0 && name[i] == '/'; i-- {
+		name = name[:i]
+	}
+	// Remove leading directory name
+	for i--; i >= 0; i-- {
+		if name[i] == '/' {
+			name = name[i+1:]
+			break
+		}
+	}
+
+	return name
+}
+
+// splitPath returns the base name and parent directory.
+func splitPath(path string) (string, string) {
+	// if no better parent is found, the path is relative from "here"
+	dirname := "."
+
+	// Remove all but one leading slash.
+	for len(path) > 1 && path[0] == '/' && path[1] == '/' {
+		path = path[1:]
+	}
+
+	i := len(path) - 1
+
+	// Remove trailing slashes.
+	for ; i > 0 && path[i] == '/'; i-- {
+		path = path[:i]
+	}
+
+	// if no slashes in path, base is path
+	basename := path
+
+	// Remove leading directory path
+	for i--; i >= 0; i-- {
+		if path[i] == '/' {
+			if i == 0 {
+				dirname = path[:1]
+			} else {
+				dirname = path[:i]
+			}
+			basename = path[i+1:]
+			break
+		}
+	}
+
+	return dirname, basename
+}
+
+func fixRootDirectory(p string) string {
+	return p
+}

compiler/internal/lib/os/path_windows.go

@@ -0,0 +1,227 @@
+// Copyright 2011 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 os
+
+const (
+	PathSeparator     = '\\' // OS-specific path separator
+	PathListSeparator = ';'  // OS-specific path list separator
+)
+
+// IsPathSeparator reports whether c is a directory separator character.
+func IsPathSeparator(c uint8) bool {
+	// NOTE: Windows accepts / as path separator.
+	return c == '\\' || c == '/'
+}
+
+// basename removes trailing slashes and the leading
+// directory name and drive letter from path name.
+func basename(name string) string {
+	// Remove drive letter
+	if len(name) == 2 && name[1] == ':' {
+		name = "."
+	} else if len(name) > 2 && name[1] == ':' {
+		name = name[2:]
+	}
+	i := len(name) - 1
+	// Remove trailing slashes
+	for ; i > 0 && (name[i] == '/' || name[i] == '\\'); i-- {
+		name = name[:i]
+	}
+	// Remove leading directory name
+	for i--; i >= 0; i-- {
+		if name[i] == '/' || name[i] == '\\' {
+			name = name[i+1:]
+			break
+		}
+	}
+	return name
+}
+
+func isAbs(path string) (b bool) {
+	v := volumeName(path)
+	if v == "" {
+		return false
+	}
+	path = path[len(v):]
+	if path == "" {
+		return false
+	}
+	return IsPathSeparator(path[0])
+}
+
+func volumeName(path string) (v string) {
+	if len(path) < 2 {
+		return ""
+	}
+	// with drive letter
+	c := path[0]
+	if path[1] == ':' &&
+		('0' <= c && c <= '9' || 'a' <= c && c <= 'z' ||
+			'A' <= c && c <= 'Z') {
+		return path[:2]
+	}
+	// is it UNC
+	if l := len(path); l >= 5 && IsPathSeparator(path[0]) && IsPathSeparator(path[1]) &&
+		!IsPathSeparator(path[2]) && path[2] != '.' {
+		// first, leading `\\` and next shouldn't be `\`. its server name.
+		for n := 3; n < l-1; n++ {
+			// second, next '\' shouldn't be repeated.
+			if IsPathSeparator(path[n]) {
+				n++
+				// third, following something characters. its share name.
+				if !IsPathSeparator(path[n]) {
+					if path[n] == '.' {
+						break
+					}
+					for ; n < l; n++ {
+						if IsPathSeparator(path[n]) {
+							break
+						}
+					}
+					return path[:n]
+				}
+				break
+			}
+		}
+	}
+	return ""
+}
+
+func fromSlash(path string) string {
+	// Replace each '/' with '\\' if present
+	var pathbuf []byte
+	var lastSlash int
+	for i, b := range path {
+		if b == '/' {
+			if pathbuf == nil {
+				pathbuf = make([]byte, len(path))
+			}
+			copy(pathbuf[lastSlash:], path[lastSlash:i])
+			pathbuf[i] = '\\'
+			lastSlash = i + 1
+		}
+	}
+	if pathbuf == nil {
+		return path
+	}
+
+	copy(pathbuf[lastSlash:], path[lastSlash:])
+	return string(pathbuf)
+}
+
+func dirname(path string) string {
+	vol := volumeName(path)
+	i := len(path) - 1
+	for i >= len(vol) && !IsPathSeparator(path[i]) {
+		i--
+	}
+	dir := path[len(vol) : i+1]
+	last := len(dir) - 1
+	if last > 0 && IsPathSeparator(dir[last]) {
+		dir = dir[:last]
+	}
+	if dir == "" {
+		dir = "."
+	}
+	return vol + dir
+}
+
+// This is set via go:linkname on runtime.canUseLongPaths, and is true when the OS
+// supports opting into proper long path handling without the need for fixups.
+var canUseLongPaths bool
+
+// fixLongPath returns the extended-length (\\?\-prefixed) form of
+// path when needed, in order to avoid the default 260 character file
+// path limit imposed by Windows. If path is not easily converted to
+// the extended-length form (for example, if path is a relative path
+// or contains .. elements), or is short enough, fixLongPath returns
+// path unmodified.
+//
+// See https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx#maxpath
+func fixLongPath(path string) string {
+	if canUseLongPaths {
+		return path
+	}
+	// Do nothing (and don't allocate) if the path is "short".
+	// Empirically (at least on the Windows Server 2013 builder),
+	// the kernel is arbitrarily okay with < 248 bytes. That
+	// matches what the docs above say:
+	// "When using an API to create a directory, the specified
+	// path cannot be so long that you cannot append an 8.3 file
+	// name (that is, the directory name cannot exceed MAX_PATH
+	// minus 12)." Since MAX_PATH is 260, 260 - 12 = 248.
+	//
+	// The MSDN docs appear to say that a normal path that is 248 bytes long
+	// will work; empirically the path must be less then 248 bytes long.
+	if len(path) < 248 {
+		// Don't fix. (This is how Go 1.7 and earlier worked,
+		// not automatically generating the \\?\ form)
+		return path
+	}
+
+	// The extended form begins with \\?\, as in
+	// \\?\c:\windows\foo.txt or \\?\UNC\server\share\foo.txt.
+	// The extended form disables evaluation of . and .. path
+	// elements and disables the interpretation of / as equivalent
+	// to \. The conversion here rewrites / to \ and elides
+	// . elements as well as trailing or duplicate separators. For
+	// simplicity it avoids the conversion entirely for relative
+	// paths or paths containing .. elements. For now,
+	// \\server\share paths are not converted to
+	// \\?\UNC\server\share paths because the rules for doing so
+	// are less well-specified.
+	if len(path) >= 2 && path[:2] == `\\` {
+		// Don't canonicalize UNC paths.
+		return path
+	}
+	if !isAbs(path) {
+		// Relative path
+		return path
+	}
+
+	const prefix = `\\?`
+
+	pathbuf := make([]byte, len(prefix)+len(path)+len(`\`))
+	copy(pathbuf, prefix)
+	n := len(path)
+	r, w := 0, len(prefix)
+	for r < n {
+		switch {
+		case IsPathSeparator(path[r]):
+			// empty block
+			r++
+		case path[r] == '.' && (r+1 == n || IsPathSeparator(path[r+1])):
+			// /./
+			r++
+		case r+1 < n && path[r] == '.' && path[r+1] == '.' && (r+2 == n || IsPathSeparator(path[r+2])):
+			// /../ is currently unhandled
+			return path
+		default:
+			pathbuf[w] = '\\'
+			w++
+			for ; r < n && !IsPathSeparator(path[r]); r++ {
+				pathbuf[w] = path[r]
+				w++
+			}
+		}
+	}
+	// A drive's root directory needs a trailing \
+	if w == len(`\\?\c:`) {
+		pathbuf[w] = '\\'
+		w++
+	}
+	return string(pathbuf[:w])
+}
+
+// fixRootDirectory fixes a reference to a drive's root directory to
+// have the required trailing slash.
+func fixRootDirectory(p string) string {
+	if len(p) == len(`\\?\c:`) {
+		if IsPathSeparator(p[0]) && IsPathSeparator(p[1]) && p[2] == '?' && IsPathSeparator(p[3]) && p[5] == ':' {
+			return p + `\`
+		}
+	}
+	return p
+}

compiler/internal/lib/os/pipe2_unix.go

@@ -0,0 +1,22 @@
+// Copyright 2017 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 dragonfly || freebsd || linux || netbsd || openbsd || solaris
+
+package os
+
+import "syscall"
+
+// Pipe returns a connected pair of Files; reads from r return bytes written to w.
+// It returns the files and an error, if any.
+func Pipe() (r *File, w *File, err error) {
+	var p [2]int
+
+	e := syscall.Pipe2(p[0:], syscall.O_CLOEXEC)
+	if e != nil {
+		return nil, nil, NewSyscallError("pipe2", e)
+	}
+
+	return newFile(p[0], "|0", kindPipe), newFile(p[1], "|1", kindPipe), nil
+}

compiler/internal/lib/os/pipe_unix.go

@@ -0,0 +1,28 @@
+// Copyright 2009 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
+
+package os
+
+import "syscall"
+
+// Pipe returns a connected pair of Files; reads from r return bytes written to w.
+// It returns the files and an error, if any.
+func Pipe() (r *File, w *File, err error) {
+	var p [2]int
+
+	// See ../syscall/exec.go for description of lock.
+	syscall.ForkLock.RLock()
+	e := syscall.Pipe(p[0:])
+	if e != nil {
+		syscall.ForkLock.RUnlock()
+		return nil, nil, NewSyscallError("pipe", e)
+	}
+	syscall.CloseOnExec(p[0])
+	syscall.CloseOnExec(p[1])
+	syscall.ForkLock.RUnlock()
+
+	return newFile(p[0], "|0", kindPipe), newFile(p[1], "|1", kindPipe), nil
+}

compiler/internal/lib/os/pipe_wasm.go

@@ -0,0 +1,16 @@
+// Copyright 2023 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 wasm
+
+package os
+
+import "syscall"
+
+// Pipe returns a connected pair of Files; reads from r return bytes written to w.
+// It returns the files and an error, if any.
+func Pipe() (r *File, w *File, err error) {
+	// Neither GOOS=js nor GOOS=wasip1 have pipes.
+	return nil, nil, NewSyscallError("pipe", syscall.ENOSYS)
+}

compiler/internal/lib/os/proc.go

@@ -0,0 +1,65 @@
+// Copyright 2009 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.
+
+// Process etc.
+
+package os
+
+import (
+	"runtime"
+	"unsafe"
+
+	"github.com/goplus/llgo/c"
+	"github.com/goplus/llgo/c/os"
+)
+
+// Args hold the command-line arguments, starting with the program name.
+var Args []string
+
+func init() {
+	if runtime.GOOS == "windows" {
+		// TODO(xsw): check windows implementation
+		// Initialized in exec_windows.go.
+		return
+	}
+	Args = runtimeArgs(int(c.Argc), c.Argv)
+}
+
+func runtimeArgs(argc int, argv **c.Char) []string {
+	args := make([]string, argc)
+	for i := 0; i < argc; i++ {
+		arg := *c.Advance(argv, i)
+		args[i] = unsafe.String((*byte)(unsafe.Pointer(arg)), c.Strlen(arg))
+	}
+	return args
+}
+
+// Getgroups returns a list of the numeric ids of groups that the caller belongs to.
+//
+// On Windows, it returns syscall.EWINDOWS. See the os/user package
+// for a possible alternative.
+func Getgroups() ([]int, error) {
+	/* TODO(xsw):
+	gids, e := syscall.Getgroups()
+	return gids, NewSyscallError("getgroups", e)
+	*/
+	panic("todo: os.Getgroups")
+}
+
+// Exit causes the current program to exit with the given status code.
+// Conventionally, code zero indicates success, non-zero an error.
+// The program terminates immediately; deferred functions are not run.
+//
+// For portability, the status code should be in the range [0, 125].
+func Exit(code int) {
+	// Inform the runtime that os.Exit is being called. If -race is
+	// enabled, this will give race detector a chance to fail the
+	// program (racy programs do not have the right to finish
+	// successfully). If coverage is enabled, then this call will
+	// enable us to write out a coverage data file.
+	// TODO(xsw):
+	// runtime_beforeExit(code)
+
+	os.Exit(c.Int(code))
+}

compiler/internal/lib/os/stat.go

@@ -0,0 +1,19 @@
+// Copyright 2017 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 os
+
+// Stat returns a FileInfo describing the named file.
+// If there is an error, it will be of type *PathError.
+func Stat(name string) (FileInfo, error) {
+	return statNolog(name)
+}
+
+// Lstat returns a FileInfo describing the named file.
+// If the file is a symbolic link, the returned FileInfo
+// describes the symbolic link. Lstat makes no attempt to follow the link.
+// If there is an error, it will be of type *PathError.
+func Lstat(name string) (FileInfo, error) {
+	return lstatNolog(name)
+}

compiler/internal/lib/os/stat_darwin.go

@@ -0,0 +1,43 @@
+// Copyright 2009 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 os
+
+import (
+	"time"
+
+	"github.com/goplus/llgo/c/syscall"
+)
+
+func fillFileStatFromSys(fs *fileStat, name string) {
+	fs.name = basename(name)
+	fs.size = fs.sys.Size
+	fs.modTime = time.Unix(fs.sys.Mtimespec.Unix())
+	fs.mode = FileMode(fs.sys.Mode & 0777)
+	switch fs.sys.Mode & syscall.S_IFMT {
+	case syscall.S_IFBLK, syscall.S_IFWHT:
+		fs.mode |= ModeDevice
+	case syscall.S_IFCHR:
+		fs.mode |= ModeDevice | ModeCharDevice
+	case syscall.S_IFDIR:
+		fs.mode |= ModeDir
+	case syscall.S_IFIFO:
+		fs.mode |= ModeNamedPipe
+	case syscall.S_IFLNK:
+		fs.mode |= ModeSymlink
+	case syscall.S_IFREG:
+		// nothing to do
+	case syscall.S_IFSOCK:
+		fs.mode |= ModeSocket
+	}
+	if fs.sys.Mode&syscall.S_ISGID != 0 {
+		fs.mode |= ModeSetgid
+	}
+	if fs.sys.Mode&syscall.S_ISUID != 0 {
+		fs.mode |= ModeSetuid
+	}
+	if fs.sys.Mode&syscall.S_ISVTX != 0 {
+		fs.mode |= ModeSticky
+	}
+}

compiler/internal/lib/os/stat_linux.go

@@ -0,0 +1,42 @@
+// Copyright 2009 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 os
+
+import (
+	"syscall"
+	"time"
+)
+
+func fillFileStatFromSys(fs *fileStat, name string) {
+	fs.name = basename(name)
+	fs.size = fs.sys.Size
+	fs.modTime = time.Unix(fs.sys.Mtim.Unix())
+	fs.mode = FileMode(fs.sys.Mode & 0777)
+	switch fs.sys.Mode & syscall.S_IFMT {
+	case syscall.S_IFBLK:
+		fs.mode |= ModeDevice
+	case syscall.S_IFCHR:
+		fs.mode |= ModeDevice | ModeCharDevice
+	case syscall.S_IFDIR:
+		fs.mode |= ModeDir
+	case syscall.S_IFIFO:
+		fs.mode |= ModeNamedPipe
+	case syscall.S_IFLNK:
+		fs.mode |= ModeSymlink
+	case syscall.S_IFREG:
+		// nothing to do
+	case syscall.S_IFSOCK:
+		fs.mode |= ModeSocket
+	}
+	if fs.sys.Mode&syscall.S_ISGID != 0 {
+		fs.mode |= ModeSetgid
+	}
+	if fs.sys.Mode&syscall.S_ISUID != 0 {
+		fs.mode |= ModeSetuid
+	}
+	if fs.sys.Mode&syscall.S_ISVTX != 0 {
+		fs.mode |= ModeSticky
+	}
+}

compiler/internal/lib/os/stat_unix.go

@@ -0,0 +1,54 @@
+// Copyright 2016 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 unix || (js && wasm) || wasip1
+
+package os
+
+import (
+	"github.com/goplus/llgo/c"
+	"github.com/goplus/llgo/c/os"
+	"github.com/goplus/llgo/compiler/internal/lib/syscall"
+)
+
+// Stat returns the FileInfo structure describing file.
+// If there is an error, it will be of type *PathError.
+func (f *File) Stat() (FileInfo, error) {
+	if f == nil {
+		return nil, ErrInvalid
+	}
+	var fs fileStat
+	err := os.Fstat(c.Int(f.fd), &fs.sys)
+	if err != 0 {
+		return nil, &PathError{Op: "stat", Path: f.name, Err: syscall.Errno(err)}
+	}
+	fillFileStatFromSys(&fs, f.name)
+	return &fs, nil
+}
+
+// statNolog stats a file with no test logging.
+func statNolog(name string) (FileInfo, error) {
+	var fs fileStat
+	err := ignoringEINTR(func() error {
+		return syscall.Stat(name, &fs.sys)
+	})
+	if err != nil {
+		return nil, &PathError{Op: "stat", Path: name, Err: err}
+	}
+	fillFileStatFromSys(&fs, name)
+	return &fs, nil
+}
+
+// lstatNolog lstats a file with no test logging.
+func lstatNolog(name string) (FileInfo, error) {
+	var fs fileStat
+	err := ignoringEINTR(func() error {
+		return syscall.Lstat(name, &fs.sys)
+	})
+	if err != nil {
+		return nil, &PathError{Op: "lstat", Path: name, Err: err}
+	}
+	fillFileStatFromSys(&fs, name)
+	return &fs, nil
+}

compiler/internal/lib/os/sticky_bsd.go

@@ -0,0 +1,11 @@
+// Copyright 2014 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 || (js && wasm) || netbsd || openbsd || solaris || wasip1
+
+package os
+
+// According to sticky(8), neither open(2) nor mkdir(2) will create
+// a file with the sticky bit set.
+const supportsCreateWithStickyBit = false

compiler/internal/lib/os/sticky_nonbsd.go

@@ -0,0 +1,9 @@
+// Copyright 2014 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 && !js && !netbsd && !openbsd && !solaris && !wasip1
+
+package os
+
+const supportsCreateWithStickyBit = true

compiler/internal/lib/os/str.go

@@ -0,0 +1,39 @@
+// Copyright 2009 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.
+
+// Simple conversions to avoid depending on strconv.
+
+package os
+
+// itox converts val (an int) to a hexadecimal string.
+func itox(val int) string {
+	if val < 0 {
+		return "-" + uitox(uint(-val))
+	}
+	return uitox(uint(val))
+}
+
+const hex = "0123456789abcdef"
+
+// uitox converts val (a uint) to a hexadecimal string.
+func uitox(val uint) string {
+	if val == 0 { // avoid string allocation
+		return "0x0"
+	}
+	var buf [20]byte // big enough for 64bit value base 16 + 0x
+	i := len(buf) - 1
+	for val >= 16 {
+		q := val / 16
+		buf[i] = hex[val%16]
+		i--
+		val = q
+	}
+	// val < 16
+	buf[i] = hex[val%16]
+	i--
+	buf[i] = 'x'
+	i--
+	buf[i] = '0'
+	return string(buf[i:])
+}

compiler/internal/lib/os/sys_js.go

@@ -0,0 +1,11 @@
+// Copyright 2018 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 && wasm
+
+package os
+
+// supportsCloseOnExec reports whether the platform supports the
+// O_CLOEXEC flag.
+const supportsCloseOnExec = false

compiler/internal/lib/os/sys_unix.go

@@ -0,0 +1,14 @@
+// Copyright 2014 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 unix
+
+package os
+
+// supportsCloseOnExec reports whether the platform supports the
+// O_CLOEXEC flag.
+// On Darwin, the O_CLOEXEC flag was introduced in OS X 10.7 (Darwin 11.0.0).
+// See https://support.apple.com/kb/HT1633.
+// On FreeBSD, the O_CLOEXEC flag was introduced in version 8.3.
+const supportsCloseOnExec = true

compiler/internal/lib/os/sys_wasip1.go

@@ -0,0 +1,11 @@
+// Copyright 2023 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 wasip1
+
+package os
+
+// supportsCloseOnExec reports whether the platform supports the
+// O_CLOEXEC flag.
+const supportsCloseOnExec = false

compiler/internal/lib/os/tempfile.go

@@ -0,0 +1,115 @@
+// Copyright 2009 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 os
+
+import (
+	"errors"
+
+	"github.com/goplus/llgo/c"
+	"github.com/goplus/llgo/compiler/internal/lib/internal/bytealg"
+	"github.com/goplus/llgo/compiler/internal/lib/internal/itoa"
+)
+
+func nextRandom() string {
+	return itoa.Uitoa(uint(uint32(c.Rand())))
+}
+
+// CreateTemp creates a new temporary file in the directory dir,
+// opens the file for reading and writing, and returns the resulting file.
+// The filename is generated by taking pattern and adding a random string to the end.
+// If pattern includes a "*", the random string replaces the last "*".
+// If dir is the empty string, CreateTemp uses the default directory for temporary files, as returned by TempDir.
+// Multiple programs or goroutines calling CreateTemp simultaneously will not choose the same file.
+// The caller can use the file's Name method to find the pathname of the file.
+// It is the caller's responsibility to remove the file when it is no longer needed.
+func CreateTemp(dir, pattern string) (*File, error) {
+	if dir == "" {
+		dir = TempDir()
+	}
+
+	prefix, suffix, err := prefixAndSuffix(pattern)
+	if err != nil {
+		return nil, &PathError{Op: "createtemp", Path: pattern, Err: err}
+	}
+	prefix = joinPath(dir, prefix)
+
+	try := 0
+	for {
+		name := prefix + nextRandom() + suffix
+		f, err := OpenFile(name, O_RDWR|O_CREATE|O_EXCL, 0600)
+		if IsExist(err) {
+			if try++; try < 10000 {
+				continue
+			}
+			return nil, &PathError{Op: "createtemp", Path: prefix + "*" + suffix, Err: ErrExist}
+		}
+		return f, err
+	}
+}
+
+var errPatternHasSeparator = errors.New("pattern contains path separator")
+
+// prefixAndSuffix splits pattern by the last wildcard "*", if applicable,
+// returning prefix as the part before "*" and suffix as the part after "*".
+func prefixAndSuffix(pattern string) (prefix, suffix string, err error) {
+	for i := 0; i < len(pattern); i++ {
+		if IsPathSeparator(pattern[i]) {
+			return "", "", errPatternHasSeparator
+		}
+	}
+	if pos := bytealg.LastIndexByteString(pattern, '*'); pos != -1 {
+		prefix, suffix = pattern[:pos], pattern[pos+1:]
+	} else {
+		prefix = pattern
+	}
+	return prefix, suffix, nil
+}
+
+// MkdirTemp creates a new temporary directory in the directory dir
+// and returns the pathname of the new directory.
+// The new directory's name is generated by adding a random string to the end of pattern.
+// If pattern includes a "*", the random string replaces the last "*" instead.
+// If dir is the empty string, MkdirTemp uses the default directory for temporary files, as returned by TempDir.
+// Multiple programs or goroutines calling MkdirTemp simultaneously will not choose the same directory.
+// It is the caller's responsibility to remove the directory when it is no longer needed.
+func MkdirTemp(dir, pattern string) (string, error) {
+	if dir == "" {
+		dir = TempDir()
+	}
+
+	prefix, suffix, err := prefixAndSuffix(pattern)
+	if err != nil {
+		return "", &PathError{Op: "mkdirtemp", Path: pattern, Err: err}
+	}
+	prefix = joinPath(dir, prefix)
+
+	try := 0
+	for {
+		name := prefix + nextRandom() + suffix
+		err := Mkdir(name, 0700)
+		if err == nil {
+			return name, nil
+		}
+		if IsExist(err) {
+			if try++; try < 10000 {
+				continue
+			}
+			return "", &PathError{Op: "mkdirtemp", Path: dir + string(PathSeparator) + prefix + "*" + suffix, Err: ErrExist}
+		}
+		if IsNotExist(err) {
+			if _, err := Stat(dir); IsNotExist(err) {
+				return "", err
+			}
+		}
+		return "", err
+	}
+}
+
+func joinPath(dir, name string) string {
+	if len(dir) > 0 && IsPathSeparator(dir[len(dir)-1]) {
+		return dir + name
+	}
+	return dir + string(PathSeparator) + name
+}

compiler/internal/lib/os/types.go

@@ -0,0 +1,126 @@
+// Copyright 2009 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 os
+
+import (
+	"io"
+	"io/fs"
+	"syscall"
+	"unsafe"
+
+	"github.com/goplus/llgo/c"
+	"github.com/goplus/llgo/c/os"
+)
+
+// Getpagesize returns the underlying system's memory page size.
+func Getpagesize() int { return syscall.Getpagesize() }
+
+// File represents an open file descriptor.
+type File struct {
+	fd          uintptr
+	name        string
+	appendMode  bool
+	nonblock    bool
+	stdoutOrErr bool
+}
+
+// write writes len(b) bytes to the File.
+// It returns the number of bytes written and an error, if any.
+func (f *File) write(b []byte) (int, error) {
+	ret := os.Write(c.Int(f.fd), unsafe.Pointer(unsafe.SliceData(b)), uintptr(len(b)))
+	if ret >= 0 {
+		return int(ret), nil
+	}
+	return 0, syscall.Errno(os.Errno())
+}
+
+/* TODO(xsw):
+// write writes len(b) bytes to the File.
+// It returns the number of bytes written and an error, if any.
+func (f *File) write(b []byte) (n int, err error) {
+	n, err = f.pfd.Write(b)
+	runtime.KeepAlive(f)
+	return n, err
+}
+*/
+
+// read reads up to len(b) bytes from the File.
+// It returns the number of bytes read and an error, if any.
+func (f *File) read(b []byte) (int, error) {
+	ret := os.Read(c.Int(f.fd), unsafe.Pointer(unsafe.SliceData(b)), uintptr(len(b)))
+	if ret > 0 {
+		return int(ret), nil
+	}
+	if ret == 0 {
+		return 0, io.EOF
+	}
+	return 0, syscall.Errno(os.Errno())
+}
+
+/* TODO(xsw):
+// read reads up to len(b) bytes from the File.
+// It returns the number of bytes read and an error, if any.
+func (f *File) read(b []byte) (n int, err error) {
+	n, err = f.pfd.Read(b)
+	runtime.KeepAlive(f)
+	return n, err
+}
+*/
+
+// A FileInfo describes a file and is returned by Stat and Lstat.
+type FileInfo = fs.FileInfo
+
+// A FileMode represents a file's mode and permission bits.
+// The bits have the same definition on all systems, so that
+// information about files can be moved from one system
+// to another portably. Not all bits apply to all systems.
+// The only required bit is ModeDir for directories.
+type FileMode = fs.FileMode
+
+// The defined file mode bits are the most significant bits of the FileMode.
+// The nine least-significant bits are the standard Unix rwxrwxrwx permissions.
+// The values of these bits should be considered part of the public API and
+// may be used in wire protocols or disk representations: they must not be
+// changed, although new bits might be added.
+const (
+	// The single letters are the abbreviations
+	// used by the String method's formatting.
+	ModeDir        = fs.ModeDir        // d: is a directory
+	ModeAppend     = fs.ModeAppend     // a: append-only
+	ModeExclusive  = fs.ModeExclusive  // l: exclusive use
+	ModeTemporary  = fs.ModeTemporary  // T: temporary file; Plan 9 only
+	ModeSymlink    = fs.ModeSymlink    // L: symbolic link
+	ModeDevice     = fs.ModeDevice     // D: device file
+	ModeNamedPipe  = fs.ModeNamedPipe  // p: named pipe (FIFO)
+	ModeSocket     = fs.ModeSocket     // S: Unix domain socket
+	ModeSetuid     = fs.ModeSetuid     // u: setuid
+	ModeSetgid     = fs.ModeSetgid     // g: setgid
+	ModeCharDevice = fs.ModeCharDevice // c: Unix character device, when ModeDevice is set
+	ModeSticky     = fs.ModeSticky     // t: sticky
+	ModeIrregular  = fs.ModeIrregular  // ?: non-regular file; nothing else is known about this file
+
+	// Mask for the type bits. For regular files, none will be set.
+	ModeType = fs.ModeType
+
+	ModePerm = fs.ModePerm // Unix permission bits, 0o777
+)
+
+func (fs *fileStat) Name() string { return fs.name }
+func (fs *fileStat) IsDir() bool  { return fs.Mode().IsDir() }
+
+// SameFile reports whether fi1 and fi2 describe the same file.
+// For example, on Unix this means that the device and inode fields
+// of the two underlying structures are identical; on other systems
+// the decision may be based on the path names.
+// SameFile only applies to results returned by this package's Stat.
+// It returns false in other cases.
+func SameFile(fi1, fi2 FileInfo) bool {
+	fs1, ok1 := fi1.(*fileStat)
+	fs2, ok2 := fi2.(*fileStat)
+	if !ok1 || !ok2 {
+		return false
+	}
+	return sameFile(fs1, fs2)
+}

compiler/internal/lib/os/types_plan9.go

@@ -0,0 +1,30 @@
+// Copyright 2009 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 os
+
+import (
+	"syscall"
+	"time"
+)
+
+// A fileStat is the implementation of FileInfo returned by Stat and Lstat.
+type fileStat struct {
+	name    string
+	size    int64
+	mode    FileMode
+	modTime time.Time
+	sys     any
+}
+
+func (fs *fileStat) Size() int64        { return fs.size }
+func (fs *fileStat) Mode() FileMode     { return fs.mode }
+func (fs *fileStat) ModTime() time.Time { return fs.modTime }
+func (fs *fileStat) Sys() any           { return fs.sys }
+
+func sameFile(fs1, fs2 *fileStat) bool {
+	a := fs1.sys.(*syscall.Dir)
+	b := fs2.sys.(*syscall.Dir)
+	return a.Qid.Path == b.Qid.Path && a.Type == b.Type && a.Dev == b.Dev
+}

compiler/internal/lib/os/types_unix.go

@@ -0,0 +1,31 @@
+// Copyright 2009 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 && !plan9
+
+package os
+
+import (
+	"time"
+
+	"github.com/goplus/llgo/compiler/internal/lib/syscall"
+)
+
+// A fileStat is the implementation of FileInfo returned by Stat and Lstat.
+type fileStat struct {
+	name    string
+	size    int64
+	mode    FileMode
+	modTime time.Time
+	sys     syscall.Stat_t
+}
+
+func (fs *fileStat) Size() int64        { return fs.size }
+func (fs *fileStat) Mode() FileMode     { return fs.mode }
+func (fs *fileStat) ModTime() time.Time { return fs.modTime }
+func (fs *fileStat) Sys() any           { return &fs.sys }
+
+func sameFile(fs1, fs2 *fileStat) bool {
+	return fs1.sys.Dev == fs2.sys.Dev && fs1.sys.Ino == fs2.sys.Ino
+}

compiler/internal/lib/os/types_windows.go

@@ -0,0 +1,241 @@
+// Copyright 2009 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 os
+
+import (
+	"internal/syscall/windows"
+	"sync"
+	"syscall"
+	"time"
+	"unsafe"
+)
+
+// A fileStat is the implementation of FileInfo returned by Stat and Lstat.
+type fileStat struct {
+	name string
+
+	// from ByHandleFileInformation, Win32FileAttributeData and Win32finddata
+	FileAttributes uint32
+	CreationTime   syscall.Filetime
+	LastAccessTime syscall.Filetime
+	LastWriteTime  syscall.Filetime
+	FileSizeHigh   uint32
+	FileSizeLow    uint32
+
+	// from Win32finddata
+	ReparseTag uint32
+
+	// what syscall.GetFileType returns
+	filetype uint32
+
+	// used to implement SameFile
+	sync.Mutex
+	path             string
+	vol              uint32
+	idxhi            uint32
+	idxlo            uint32
+	appendNameToPath bool
+}
+
+// newFileStatFromGetFileInformationByHandle calls GetFileInformationByHandle
+// to gather all required information about the file handle h.
+func newFileStatFromGetFileInformationByHandle(path string, h syscall.Handle) (fs *fileStat, err error) {
+	var d syscall.ByHandleFileInformation
+	err = syscall.GetFileInformationByHandle(h, &d)
+	if err != nil {
+		return nil, &PathError{Op: "GetFileInformationByHandle", Path: path, Err: err}
+	}
+
+	var ti windows.FILE_ATTRIBUTE_TAG_INFO
+	err = windows.GetFileInformationByHandleEx(h, windows.FileAttributeTagInfo, (*byte)(unsafe.Pointer(&ti)), uint32(unsafe.Sizeof(ti)))
+	if err != nil {
+		if errno, ok := err.(syscall.Errno); ok && errno == windows.ERROR_INVALID_PARAMETER {
+			// It appears calling GetFileInformationByHandleEx with
+			// FILE_ATTRIBUTE_TAG_INFO fails on FAT file system with
+			// ERROR_INVALID_PARAMETER. Clear ti.ReparseTag in that
+			// instance to indicate no symlinks are possible.
+			ti.ReparseTag = 0
+		} else {
+			return nil, &PathError{Op: "GetFileInformationByHandleEx", Path: path, Err: err}
+		}
+	}
+
+	return &fileStat{
+		name:           basename(path),
+		FileAttributes: d.FileAttributes,
+		CreationTime:   d.CreationTime,
+		LastAccessTime: d.LastAccessTime,
+		LastWriteTime:  d.LastWriteTime,
+		FileSizeHigh:   d.FileSizeHigh,
+		FileSizeLow:    d.FileSizeLow,
+		vol:            d.VolumeSerialNumber,
+		idxhi:          d.FileIndexHigh,
+		idxlo:          d.FileIndexLow,
+		ReparseTag:     ti.ReparseTag,
+		// fileStat.path is used by os.SameFile to decide if it needs
+		// to fetch vol, idxhi and idxlo. But these are already set,
+		// so set fileStat.path to "" to prevent os.SameFile doing it again.
+	}, nil
+}
+
+// newFileStatFromWin32finddata copies all required information
+// from syscall.Win32finddata d into the newly created fileStat.
+func newFileStatFromWin32finddata(d *syscall.Win32finddata) *fileStat {
+	fs := &fileStat{
+		FileAttributes: d.FileAttributes,
+		CreationTime:   d.CreationTime,
+		LastAccessTime: d.LastAccessTime,
+		LastWriteTime:  d.LastWriteTime,
+		FileSizeHigh:   d.FileSizeHigh,
+		FileSizeLow:    d.FileSizeLow,
+	}
+	if d.FileAttributes&syscall.FILE_ATTRIBUTE_REPARSE_POINT != 0 {
+		// Per https://learn.microsoft.com/en-us/windows/win32/api/minwinbase/ns-minwinbase-win32_find_dataw:
+		// “If the dwFileAttributes member includes the FILE_ATTRIBUTE_REPARSE_POINT
+		// attribute, this member specifies the reparse point tag. Otherwise, this
+		// value is undefined and should not be used.”
+		fs.ReparseTag = d.Reserved0
+	}
+	return fs
+}
+
+func (fs *fileStat) isSymlink() bool {
+	// As of https://go.dev/cl/86556, we treat MOUNT_POINT reparse points as
+	// symlinks because otherwise certain directory junction tests in the
+	// path/filepath package would fail.
+	//
+	// However,
+	// https://learn.microsoft.com/en-us/windows/win32/fileio/hard-links-and-junctions
+	// seems to suggest that directory junctions should be treated like hard
+	// links, not symlinks.
+	//
+	// TODO(bcmills): Get more input from Microsoft on what the behavior ought to
+	// be for MOUNT_POINT reparse points.
+
+	return fs.ReparseTag == syscall.IO_REPARSE_TAG_SYMLINK ||
+		fs.ReparseTag == windows.IO_REPARSE_TAG_MOUNT_POINT
+}
+
+func (fs *fileStat) Size() int64 {
+	return int64(fs.FileSizeHigh)<<32 + int64(fs.FileSizeLow)
+}
+
+func (fs *fileStat) Mode() (m FileMode) {
+	if fs.FileAttributes&syscall.FILE_ATTRIBUTE_READONLY != 0 {
+		m |= 0444
+	} else {
+		m |= 0666
+	}
+	if fs.isSymlink() {
+		return m | ModeSymlink
+	}
+	if fs.FileAttributes&syscall.FILE_ATTRIBUTE_DIRECTORY != 0 {
+		m |= ModeDir | 0111
+	}
+	switch fs.filetype {
+	case syscall.FILE_TYPE_PIPE:
+		m |= ModeNamedPipe
+	case syscall.FILE_TYPE_CHAR:
+		m |= ModeDevice | ModeCharDevice
+	}
+	if fs.FileAttributes&syscall.FILE_ATTRIBUTE_REPARSE_POINT != 0 && m&ModeType == 0 {
+		m |= ModeIrregular
+	}
+	return m
+}
+
+func (fs *fileStat) ModTime() time.Time {
+	return time.Unix(0, fs.LastWriteTime.Nanoseconds())
+}
+
+// Sys returns syscall.Win32FileAttributeData for file fs.
+func (fs *fileStat) Sys() any {
+	return &syscall.Win32FileAttributeData{
+		FileAttributes: fs.FileAttributes,
+		CreationTime:   fs.CreationTime,
+		LastAccessTime: fs.LastAccessTime,
+		LastWriteTime:  fs.LastWriteTime,
+		FileSizeHigh:   fs.FileSizeHigh,
+		FileSizeLow:    fs.FileSizeLow,
+	}
+}
+
+func (fs *fileStat) loadFileId() error {
+	fs.Lock()
+	defer fs.Unlock()
+	if fs.path == "" {
+		// already done
+		return nil
+	}
+	var path string
+	if fs.appendNameToPath {
+		path = fs.path + `\` + fs.name
+	} else {
+		path = fs.path
+	}
+	pathp, err := syscall.UTF16PtrFromString(path)
+	if err != nil {
+		return err
+	}
+
+	// Per https://learn.microsoft.com/en-us/windows/win32/fileio/reparse-points-and-file-operations,
+	// “Applications that use the CreateFile function should specify the
+	// FILE_FLAG_OPEN_REPARSE_POINT flag when opening the file if it is a reparse
+	// point.”
+	//
+	// And per https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilew,
+	// “If the file is not a reparse point, then this flag is ignored.”
+	//
+	// So we set FILE_FLAG_OPEN_REPARSE_POINT unconditionally, since we want
+	// information about the reparse point itself.
+	//
+	// If the file is a symlink, the symlink target should have already been
+	// resolved when the fileStat was created, so we don't need to worry about
+	// resolving symlink reparse points again here.
+	attrs := uint32(syscall.FILE_FLAG_BACKUP_SEMANTICS | syscall.FILE_FLAG_OPEN_REPARSE_POINT)
+
+	h, err := syscall.CreateFile(pathp, 0, 0, nil, syscall.OPEN_EXISTING, attrs, 0)
+	if err != nil {
+		return err
+	}
+	defer syscall.CloseHandle(h)
+	var i syscall.ByHandleFileInformation
+	err = syscall.GetFileInformationByHandle(h, &i)
+	if err != nil {
+		return err
+	}
+	fs.path = ""
+	fs.vol = i.VolumeSerialNumber
+	fs.idxhi = i.FileIndexHigh
+	fs.idxlo = i.FileIndexLow
+	return nil
+}
+
+// saveInfoFromPath saves full path of the file to be used by os.SameFile later,
+// and set name from path.
+func (fs *fileStat) saveInfoFromPath(path string) error {
+	fs.path = path
+	if !isAbs(fs.path) {
+		var err error
+		fs.path, err = syscall.FullPath(fs.path)
+		if err != nil {
+			return &PathError{Op: "FullPath", Path: path, Err: err}
+		}
+	}
+	fs.name = basename(path)
+	return nil
+}
+
+func sameFile(fs1, fs2 *fileStat) bool {
+	e := fs1.loadFileId()
+	if e != nil {
+		return false
+	}
+	e = fs2.loadFileId()
+	if e != nil {
+		return false
+	}
+	return fs1.vol == fs2.vol && fs1.idxhi == fs2.idxhi && fs1.idxlo == fs2.idxlo
+}

compiler/internal/lib/os/wait_unimp.go

@@ -0,0 +1,21 @@
+// Copyright 2016 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.
+
+// aix, darwin, js/wasm, openbsd, solaris and wasip1/wasm don't implement
+// waitid/wait6.
+
+//go:build aix || darwin || (js && wasm) || openbsd || solaris || wasip1
+
+package os
+
+// blockUntilWaitable attempts to block until a call to p.Wait will
+// succeed immediately, and reports whether it has done so.
+// It does not actually call p.Wait.
+// This version is used on systems that do not implement waitid,
+// or where we have not implemented it yet. Note that this is racy:
+// a call to Process.Signal can in an extremely unlikely case send a
+// signal to the wrong process, see issue #13987.
+func (p *Process) blockUntilWaitable() (bool, error) {
+	return false, nil
+}

compiler/internal/lib/os/wait_wait6.go

@@ -0,0 +1,32 @@
+// Copyright 2016 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 dragonfly || freebsd || netbsd
+
+package os
+
+import (
+	"syscall"
+)
+
+// blockUntilWaitable attempts to block until a call to p.Wait will
+// succeed immediately, and reports whether it has done so.
+// It does not actually call p.Wait.
+func (p *Process) blockUntilWaitable() (bool, error) {
+	var errno syscall.Errno
+	for {
+		_, errno = wait6(_P_PID, p.Pid, syscall.WEXITED|syscall.WNOWAIT)
+		if errno != syscall.EINTR {
+			break
+		}
+	}
+	// TODO(xsw):
+	// runtime.KeepAlive(p)
+	if errno == syscall.ENOSYS {
+		return false, nil
+	} else if errno != 0 {
+		return false, NewSyscallError("wait6", errno)
+	}
+	return true, nil
+}

compiler/internal/lib/os/wait_waitid.go

@@ -0,0 +1,55 @@
+// Copyright 2016 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.
+
+// We used to used this code for Darwin, but according to issue #19314
+// waitid returns if the process is stopped, even when using WEXITED.
+
+//go:build linux
+
+package os
+
+import (
+	"syscall"
+	_ "unsafe"
+
+	"github.com/goplus/llgo/c"
+)
+
+const _P_PID = 1
+
+// int waitid(idtype_t idtype, id_t id, siginfo_t *infop, int options);
+//
+//go:linkname waitid C.waitid
+func waitid(idtype, id uintptr, infop *uint64, options c.Int) c.Int
+
+// blockUntilWaitable attempts to block until a call to p.Wait will
+// succeed immediately, and reports whether it has done so.
+// It does not actually call p.Wait.
+func (p *Process) blockUntilWaitable() (bool, error) {
+	// The waitid system call expects a pointer to a siginfo_t,
+	// which is 128 bytes on all Linux systems.
+	// On darwin/amd64, it requires 104 bytes.
+	// We don't care about the values it returns.
+	var siginfo [16]uint64
+	psig := &siginfo[0]
+	var e syscall.Errno
+	for {
+		e = syscall.Errno(waitid(_P_PID, uintptr(p.Pid), psig, syscall.WEXITED|syscall.WNOWAIT))
+		if e != syscall.EINTR {
+			break
+		}
+	}
+	// TODO(xsw):
+	// runtime.KeepAlive(p)
+	if e != 0 {
+		// waitid has been available since Linux 2.6.9, but
+		// reportedly is not available in Ubuntu on Windows.
+		// See issue 16610.
+		if e == syscall.ENOSYS {
+			return false, nil
+		}
+		return false, NewSyscallError("waitid", e)
+	}
+	return true, nil
+}