1 files changed, 373 insertions, 0 deletions
diff --git a/src/cmd/internal/objabi/flag.go b/src/cmd/internal/objabi/flag.go
new file mode 100644
index 0000000..847ed48
--- /dev/null
+++ b/src/cmd/internal/objabi/flag.go
@@ -0,0 +1,373 @@
+// 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/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 or string)", f.Name, f.Type))
+		case *int, *string:
+			// 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
+			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 ""
+}