src/cmd/internal/objabi/flag.go - go - Git at Google

 // Copyright 2015 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 package objabi

 import (
 	"flag"
 	"fmt"
 	"internal/bisect"
 	"internal/buildcfg"
 	"io"
 	"log"
 	"os"
 	"reflect"
 	"sort"
 	"strconv"
 	"strings"
 )

 func Flagcount(name, usage string, val *int) {
 	flag.Var((*count)(val), name, usage)
 }

 func Flagfn1(name, usage string, f func(string)) {
 	flag.Var(fn1(f), name, usage)
 }

 func Flagprint(w io.Writer) {
 	flag.CommandLine.SetOutput(w)
 	flag.PrintDefaults()
 }

 func Flagparse(usage func()) {
 	flag.Usage = usage
 	os.Args = expandArgs(os.Args)
 	flag.Parse()
 }

 // expandArgs expands "response files" arguments in the provided slice.
 //
 // A "response file" argument starts with '@' and the rest of that
 // argument is a filename with CR-or-CRLF-separated arguments. Each
 // argument in the named files can also contain response file
 // arguments. See Issue 18468.
 //
 // The returned slice 'out' aliases 'in' iff the input did not contain
 // any response file arguments.
 //
 // TODO: handle relative paths of recursive expansions in different directories?
 // Is there a spec for this? Are relative paths allowed?
 func expandArgs(in []string) (out []string) {
 	// out is nil until we see a "@" argument.
 	for i, s := range in {
 		if strings.HasPrefix(s, "@") {
 			if out == nil {
 				out = make([]string, 0, len(in)*2)
 				out = append(out, in[:i]...)
 			}
 			slurp, err := os.ReadFile(s[1:])
 			if err != nil {
 				log.Fatal(err)
 			}
 			args := strings.Split(strings.TrimSpace(strings.Replace(string(slurp), "\r", "", -1)), "\n")
 			for i, arg := range args {
 				args[i] = DecodeArg(arg)
 			}
 			out = append(out, expandArgs(args)...)
 		} else if out != nil {
 			out = append(out, s)
 		}
 	}
 	if out == nil {
 		return in
 	}
 	return
 }

 func AddVersionFlag() {
 	flag.Var(versionFlag{}, "V", "print version and exit")
 }

 var buildID string // filled in by linker

 type versionFlag struct{}

 func (versionFlag) IsBoolFlag() bool { return true }
 func (versionFlag) Get() interface{} { return nil }
 func (versionFlag) String() string   { return "" }
 func (versionFlag) Set(s string) error {
 	name := os.Args[0]
 	name = name[strings.LastIndex(name, `/`)+1:]
 	name = name[strings.LastIndex(name, `\`)+1:]
 	name = strings.TrimSuffix(name, ".exe")

 	p := ""

 	if s == "goexperiment" {
 		// test/run.go uses this to discover the full set of
 		// experiment tags. Report everything.
 		p = " X:" + strings.Join(buildcfg.Experiment.All(), ",")
 	} else {
 		// If the enabled experiments differ from the baseline,
 		// include that difference.
 		if goexperiment := buildcfg.Experiment.String(); goexperiment != "" {
 			p = " X:" + goexperiment
 		}
 	}

 	// The go command invokes -V=full to get a unique identifier
 	// for this tool. It is assumed that the release version is sufficient
 	// for releases, but during development we include the full
 	// build ID of the binary, so that if the compiler is changed and
 	// rebuilt, we notice and rebuild all packages.
 	if s == "full" {
 		if strings.HasPrefix(buildcfg.Version, "devel") {
 			p += " buildID=" + buildID
 		}
 	}

 	fmt.Printf("%s version %s%s\n", name, buildcfg.Version, p)
 	os.Exit(0)
 	return nil
 }

 // count is a flag.Value that is like a flag.Bool and a flag.Int.
 // If used as -name, it increments the count, but -name=x sets the count.
 // Used for verbose flag -v.
 type count int

 func (c *count) String() string {
 	return fmt.Sprint(int(*c))
 }

 func (c *count) Set(s string) error {
 	switch s {
 	case "true":
 		*c++
 	case "false":
 		*c = 0
 	default:
 		n, err := strconv.Atoi(s)
 		if err != nil {
 			return fmt.Errorf("invalid count %q", s)
 		}
 		*c = count(n)
 	}
 	return nil
 }

 func (c *count) Get() interface{} {
 	return int(*c)
 }

 func (c *count) IsBoolFlag() bool {
 	return true
 }

 func (c *count) IsCountFlag() bool {
 	return true
 }

 type fn1 func(string)

 func (f fn1) Set(s string) error {
 	f(s)
 	return nil
 }

 func (f fn1) String() string { return "" }

 // DecodeArg decodes an argument.
 //
 // This function is public for testing with the parallel encoder.
 func DecodeArg(arg string) string {
 	// If no encoding, fastpath out.
 	if !strings.ContainsAny(arg, "\\\n") {
 		return arg
 	}

 	var b strings.Builder
 	var wasBS bool
 	for _, r := range arg {
 		if wasBS {
 			switch r {
 			case '\\':
 				b.WriteByte('\\')
 			case 'n':
 				b.WriteByte('\n')
 			default:
 				// This shouldn't happen. The only backslashes that reach here
 				// should encode '\n' and '\\' exclusively.
 				panic("badly formatted input")
 			}
 		} else if r == '\\' {
 			wasBS = true
 			continue
 		} else {
 			b.WriteRune(r)
 		}
 		wasBS = false
 	}
 	return b.String()
 }

 type debugField struct {
 	name         string
 	help         string
 	concurrentOk bool        // true if this field/flag is compatible with concurrent compilation
 	val          interface{} // *int or *string
 }

 type DebugFlag struct {
 	tab          map[string]debugField
 	concurrentOk *bool    // this is non-nil only for compiler's DebugFlags, but only compiler has concurrent:ok fields
 	debugSSA     DebugSSA // this is non-nil only for compiler's DebugFlags.
 }

 // A DebugSSA function is called to set a -d ssa/... option.
 // If nil, those options are reported as invalid options.
 // If DebugSSA returns a non-empty string, that text is reported as a compiler error.
 // If phase is "help", it should print usage information and terminate the process.
 type DebugSSA func(phase, flag string, val int, valString string) string

 // NewDebugFlag constructs a DebugFlag for the fields of debug, which
 // must be a pointer to a struct.
 //
 // Each field of *debug is a different value, named for the lower-case of the field name.
 // Each field must be an int or string and must have a `help` struct tag.
 // There may be an "Any bool" field, which will be set if any debug flags are set.
 //
 // The returned flag takes a comma-separated list of settings.
 // Each setting is name=value; for ints, name is short for name=1.
 //
 // If debugSSA is non-nil, any debug flags of the form ssa/... will be
 // passed to debugSSA for processing.
 func NewDebugFlag(debug interface{}, debugSSA DebugSSA) *DebugFlag {
 	flag := &DebugFlag{
 		tab:      make(map[string]debugField),
 		debugSSA: debugSSA,
 	}

 	v := reflect.ValueOf(debug).Elem()
 	t := v.Type()
 	for i := 0; i < t.NumField(); i++ {
 		f := t.Field(i)
 		ptr := v.Field(i).Addr().Interface()
 		if f.Name == "ConcurrentOk" {
 			switch ptr := ptr.(type) {
 			default:
 				panic("debug.ConcurrentOk must have type bool")
 			case *bool:
 				flag.concurrentOk = ptr
 			}
 			continue
 		}
 		name := strings.ToLower(f.Name)
 		help := f.Tag.Get("help")
 		if help == "" {
 			panic(fmt.Sprintf("debug.%s is missing help text", f.Name))
 		}
 		concurrent := f.Tag.Get("concurrent")

 		switch ptr.(type) {
 		default:
 			panic(fmt.Sprintf("debug.%s has invalid type %v (must be int, string, or *bisect.Matcher)", f.Name, f.Type))
 		case *int, *string, **bisect.Matcher:
 			// ok
 		}
 		flag.tab[name] = debugField{name, help, concurrent == "ok", ptr}
 	}

 	return flag
 }

 func (f *DebugFlag) Set(debugstr string) error {
 	if debugstr == "" {
 		return nil
 	}
 	for _, name := range strings.Split(debugstr, ",") {
 		if name == "" {
 			continue
 		}
 		// display help about the debug option itself and quit
 		if name == "help" {
 			fmt.Print(debugHelpHeader)
 			maxLen, names := 0, []string{}
 			if f.debugSSA != nil {
 				maxLen = len("ssa/help")
 			}
 			for name := range f.tab {
 				if len(name) > maxLen {
 					maxLen = len(name)
 				}
 				names = append(names, name)
 			}
 			sort.Strings(names)
 			// Indent multi-line help messages.
 			nl := fmt.Sprintf("\n\t%-*s\t", maxLen, "")
 			for _, name := range names {
 				help := f.tab[name].help
 				fmt.Printf("\t%-*s\t%s\n", maxLen, name, strings.Replace(help, "\n", nl, -1))
 			}
 			if f.debugSSA != nil {
 				// ssa options have their own help
 				fmt.Printf("\t%-*s\t%s\n", maxLen, "ssa/help", "print help about SSA debugging")
 			}
 			os.Exit(0)
 		}

 		val, valstring, haveInt := 1, "", true
 		if i := strings.IndexAny(name, "=:"); i >= 0 {
 			var err error
 			name, valstring = name[:i], name[i+1:]
 			val, err = strconv.Atoi(valstring)
 			if err != nil {
 				val, haveInt = 1, false
 			}
 		}

 		if t, ok := f.tab[name]; ok {
 			switch vp := t.val.(type) {
 			case nil:
 				// Ignore
 			case *string:
 				*vp = valstring
 			case *int:
 				if !haveInt {
 					log.Fatalf("invalid debug value %v", name)
 				}
 				*vp = val
 			case **bisect.Matcher:
 				var err error
 				*vp, err = bisect.New(valstring)
 				if err != nil {
 					log.Fatalf("debug flag %v: %v", name, err)
 				}
 			default:
 				panic("bad debugtab type")
 			}
 			// assembler DebugFlags don't have a ConcurrentOk field to reset, so check against that.
 			if !t.concurrentOk && f.concurrentOk != nil {
 				*f.concurrentOk = false
 			}
 		} else if f.debugSSA != nil && strings.HasPrefix(name, "ssa/") {
 			// expect form ssa/phase/flag
 			// e.g. -d=ssa/generic_cse/time
 			// _ in phase name also matches space
 			phase := name[4:]
 			flag := "debug" // default flag is debug
 			if i := strings.Index(phase, "/"); i >= 0 {
 				flag = phase[i+1:]
 				phase = phase[:i]
 			}
 			err := f.debugSSA(phase, flag, val, valstring)
 			if err != "" {
 				log.Fatalf(err)
 			}
 			// Setting this false for -d=ssa/... preserves old behavior
 			// of turning off concurrency for any debug flags.
 			// It's not known for sure if this is necessary, but it is safe.
 			*f.concurrentOk = false

 		} else {
 			return fmt.Errorf("unknown debug key %s\n", name)
 		}
 	}

 	return nil
 }

 const debugHelpHeader = `usage: -d arg[,arg]* and arg is <key>[=<value>]

 <key> is one of:

 `

 func (f *DebugFlag) String() string {
 	return ""
 }
	// Copyright 2015 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	package objabi

	import (
	"flag"
	"fmt"
	"internal/bisect"
	"internal/buildcfg"
	"io"
	"log"
	"os"
	"reflect"
	"sort"
	"strconv"
	"strings"
	)

	func Flagcount(name, usage string, val *int) {
	flag.Var((*count)(val), name, usage)
	}

	func Flagfn1(name, usage string, f func(string)) {
	flag.Var(fn1(f), name, usage)
	}

	func Flagprint(w io.Writer) {
	flag.CommandLine.SetOutput(w)
	flag.PrintDefaults()
	}

	func Flagparse(usage func()) {
	flag.Usage = usage
	os.Args = expandArgs(os.Args)
	flag.Parse()
	}

	// expandArgs expands "response files" arguments in the provided slice.
	//
	// A "response file" argument starts with '@' and the rest of that
	// argument is a filename with CR-or-CRLF-separated arguments. Each
	// argument in the named files can also contain response file
	// arguments. See Issue 18468.
	//
	// The returned slice 'out' aliases 'in' iff the input did not contain
	// any response file arguments.
	//
	// TODO: handle relative paths of recursive expansions in different directories?
	// Is there a spec for this? Are relative paths allowed?
	func expandArgs(in []string) (out []string) {
	// out is nil until we see a "@" argument.
	for i, s := range in {
	if strings.HasPrefix(s, "@") {
	if out == nil {
	out = make([]string, 0, len(in)*2)
	out = append(out, in[:i]...)
	}
	slurp, err := os.ReadFile(s[1:])
	if err != nil {
	log.Fatal(err)
	}
	args := strings.Split(strings.TrimSpace(strings.Replace(string(slurp), "\r", "", -1)), "\n")
	for i, arg := range args {
	args[i] = DecodeArg(arg)
	}
	out = append(out, expandArgs(args)...)
	} else if out != nil {
	out = append(out, s)
	}
	}
	if out == nil {
	return in
	}
	return
	}

	func AddVersionFlag() {
	flag.Var(versionFlag{}, "V", "print version and exit")
	}

	var buildID string // filled in by linker

	type versionFlag struct{}

	func (versionFlag) IsBoolFlag() bool { return true }
	func (versionFlag) Get() interface{} { return nil }
	func (versionFlag) String() string { return "" }
	func (versionFlag) Set(s string) error {
	name := os.Args[0]
	name = name[strings.LastIndex(name, `/`)+1:]
	name = name[strings.LastIndex(name, `\`)+1:]
	name = strings.TrimSuffix(name, ".exe")

	p := ""

	if s == "goexperiment" {
	// test/run.go uses this to discover the full set of
	// experiment tags. Report everything.
	p = " X:" + strings.Join(buildcfg.Experiment.All(), ",")
	} else {
	// If the enabled experiments differ from the baseline,
	// include that difference.
	if goexperiment := buildcfg.Experiment.String(); goexperiment != "" {
	p = " X:" + goexperiment
	}
	}

	// The go command invokes -V=full to get a unique identifier
	// for this tool. It is assumed that the release version is sufficient
	// for releases, but during development we include the full
	// build ID of the binary, so that if the compiler is changed and
	// rebuilt, we notice and rebuild all packages.
	if s == "full" {
	if strings.HasPrefix(buildcfg.Version, "devel") {
	p += " buildID=" + buildID
	}
	}

	fmt.Printf("%s version %s%s\n", name, buildcfg.Version, p)
	os.Exit(0)
	return nil
	}

	// count is a flag.Value that is like a flag.Bool and a flag.Int.
	// If used as -name, it increments the count, but -name=x sets the count.
	// Used for verbose flag -v.
	type count int

	func (c *count) String() string {
	return fmt.Sprint(int(*c))
	}

	func (c *count) Set(s string) error {
	switch s {
	case "true":
	*c++
	case "false":
	*c = 0
	default:
	n, err := strconv.Atoi(s)
	if err != nil {
	return fmt.Errorf("invalid count %q", s)
	}
	*c = count(n)
	}
	return nil
	}

	func (c *count) Get() interface{} {
	return int(*c)
	}

	func (c *count) IsBoolFlag() bool {
	return true
	}

	func (c *count) IsCountFlag() bool {
	return true
	}

	type fn1 func(string)

	func (f fn1) Set(s string) error {
	f(s)
	return nil
	}

	func (f fn1) String() string { return "" }

	// DecodeArg decodes an argument.
	//
	// This function is public for testing with the parallel encoder.
	func DecodeArg(arg string) string {
	// If no encoding, fastpath out.
	if !strings.ContainsAny(arg, "\\\n") {
	return arg
	}

	var b strings.Builder
	var wasBS bool
	for _, r := range arg {
	if wasBS {
	switch r {
	case '\\':
	b.WriteByte('\\')
	case 'n':
	b.WriteByte('\n')
	default:
	// This shouldn't happen. The only backslashes that reach here
	// should encode '\n' and '\\' exclusively.
	panic("badly formatted input")
	}
	} else if r == '\\' {
	wasBS = true
	continue
	} else {
	b.WriteRune(r)
	}
	wasBS = false
	}
	return b.String()
	}

	type debugField struct {
	name string
	help string
	concurrentOk bool // true if this field/flag is compatible with concurrent compilation
	val interface{} // int or string
	}

	type DebugFlag struct {
	tab map[string]debugField
	concurrentOk *bool // this is non-nil only for compiler's DebugFlags, but only compiler has concurrent:ok fields
	debugSSA DebugSSA // this is non-nil only for compiler's DebugFlags.
	}

	// A DebugSSA function is called to set a -d ssa/... option.
	// If nil, those options are reported as invalid options.
	// If DebugSSA returns a non-empty string, that text is reported as a compiler error.
	// If phase is "help", it should print usage information and terminate the process.
	type DebugSSA func(phase, flag string, val int, valString string) string

	// NewDebugFlag constructs a DebugFlag for the fields of debug, which
	// must be a pointer to a struct.
	//
	// Each field of *debug is a different value, named for the lower-case of the field name.
	// Each field must be an int or string and must have a `help` struct tag.
	// There may be an "Any bool" field, which will be set if any debug flags are set.
	//
	// The returned flag takes a comma-separated list of settings.
	// Each setting is name=value; for ints, name is short for name=1.
	//
	// If debugSSA is non-nil, any debug flags of the form ssa/... will be
	// passed to debugSSA for processing.
	func NewDebugFlag(debug interface{}, debugSSA DebugSSA) *DebugFlag {
	flag := &DebugFlag{
	tab: make(map[string]debugField),
	debugSSA: debugSSA,
	}

	v := reflect.ValueOf(debug).Elem()
	t := v.Type()
	for i := 0; i < t.NumField(); i++ {
	f := t.Field(i)
	ptr := v.Field(i).Addr().Interface()
	if f.Name == "ConcurrentOk" {
	switch ptr := ptr.(type) {
	default:
	panic("debug.ConcurrentOk must have type bool")
	case *bool:
	flag.concurrentOk = ptr
	}
	continue
	}
	name := strings.ToLower(f.Name)
	help := f.Tag.Get("help")
	if help == "" {
	panic(fmt.Sprintf("debug.%s is missing help text", f.Name))
	}
	concurrent := f.Tag.Get("concurrent")

	switch ptr.(type) {
	default:
	panic(fmt.Sprintf("debug.%s has invalid type %v (must be int, string, or *bisect.Matcher)", f.Name, f.Type))
	case int, string, **bisect.Matcher:
	// ok
	}
	flag.tab[name] = debugField{name, help, concurrent == "ok", ptr}
	}

	return flag
	}

	func (f *DebugFlag) Set(debugstr string) error {
	if debugstr == "" {
	return nil
	}
	for _, name := range strings.Split(debugstr, ",") {
	if name == "" {
	continue
	}
	// display help about the debug option itself and quit
	if name == "help" {
	fmt.Print(debugHelpHeader)
	maxLen, names := 0, []string{}
	if f.debugSSA != nil {
	maxLen = len("ssa/help")
	}
	for name := range f.tab {
	if len(name) > maxLen {
	maxLen = len(name)
	}
	names = append(names, name)
	}
	sort.Strings(names)
	// Indent multi-line help messages.
	nl := fmt.Sprintf("\n\t%-*s\t", maxLen, "")
	for _, name := range names {
	help := f.tab[name].help
	fmt.Printf("\t%-*s\t%s\n", maxLen, name, strings.Replace(help, "\n", nl, -1))
	}
	if f.debugSSA != nil {
	// ssa options have their own help
	fmt.Printf("\t%-*s\t%s\n", maxLen, "ssa/help", "print help about SSA debugging")
	}
	os.Exit(0)
	}

	val, valstring, haveInt := 1, "", true
	if i := strings.IndexAny(name, "=:"); i >= 0 {
	var err error
	name, valstring = name[:i], name[i+1:]
	val, err = strconv.Atoi(valstring)
	if err != nil {
	val, haveInt = 1, false
	}
	}

	if t, ok := f.tab[name]; ok {
	switch vp := t.val.(type) {
	case nil:
	// Ignore
	case *string:
	*vp = valstring
	case *int:
	if !haveInt {
	log.Fatalf("invalid debug value %v", name)
	}
	*vp = val
	case **bisect.Matcher:
	var err error
	*vp, err = bisect.New(valstring)
	if err != nil {
	log.Fatalf("debug flag %v: %v", name, err)
	}
	default:
	panic("bad debugtab type")
	}
	// assembler DebugFlags don't have a ConcurrentOk field to reset, so check against that.
	if !t.concurrentOk && f.concurrentOk != nil {
	*f.concurrentOk = false
	}
	} else if f.debugSSA != nil && strings.HasPrefix(name, "ssa/") {
	// expect form ssa/phase/flag
	// e.g. -d=ssa/generic_cse/time
	// _ in phase name also matches space
	phase := name[4:]
	flag := "debug" // default flag is debug
	if i := strings.Index(phase, "/"); i >= 0 {
	flag = phase[i+1:]
	phase = phase[:i]
	}
	err := f.debugSSA(phase, flag, val, valstring)
	if err != "" {
	log.Fatalf(err)
	}
	// Setting this false for -d=ssa/... preserves old behavior
	// of turning off concurrency for any debug flags.
	// It's not known for sure if this is necessary, but it is safe.
	*f.concurrentOk = false

	} else {
	return fmt.Errorf("unknown debug key %s\n", name)
	}
	}

	return nil
	}

	const debugHelpHeader = `usage: -d arg[,arg]* and arg is <key>[=<value>]

	<key> is one of:

	`

	func (f *DebugFlag) String() string {
	return ""
	}