cmd/dist: move functions for the better

This belongs to a series of clean-up changes (see below) for cmd/dist.
This is change (6).

These changes include:
(1)  apply minor fixes
(2)  restore behavior of branchtag
(3)  unleash bootstrap optimization for windows
(4)  use standard generated code header
(5)  remove trivial variables + functions
(6)  move functions for the better
(7)  simplify code segments
(8)  use bytes.Buffer for code generation
(9)  rename variables + functions
(10) remove doc.go

Change-Id: I1c49e3427079194210a6416057100a7e94a37619
Reviewed-on: https://go-review.googlesource.com/61012
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/cmd/dist/build.go

@@ -942,24 +942,6 @@ func clean() {
  * command implementations
  */
 
-func usage() {
-	xprintf("usage: go tool dist [command]\n" +
-		"Commands are:\n" +
-		"\n" +
-		"banner         print installation banner\n" +
-		"bootstrap      rebuild everything\n" +
-		"clean          deletes all built files\n" +
-		"env [-p]       print environment (-p: include $PATH)\n" +
-		"install [dir]  install individual directory\n" +
-		"list [-json]   list all supported platforms\n" +
-		"test [-h]      run Go test(s)\n" +
-		"version        print Go version\n" +
-		"\n" +
-		"All commands take -v flags to emit extra information.\n",
-	)
-	xexit(2)
-}
-
 // The env command prints the default environment.
 func cmdenv() {
 	path := flag.Bool("p", false, "emit updated PATH")

src/cmd/dist/main.go

@@ -8,9 +8,29 @@ import (
 	"flag"
 	"fmt"
 	"os"
+	"runtime"
 	"strconv"
+	"strings"
 )
 
+func usage() {
+	xprintf("usage: go tool dist [command]\n" +
+		"Commands are:\n" +
+		"\n" +
+		"banner         print installation banner\n" +
+		"bootstrap      rebuild everything\n" +
+		"clean          deletes all built files\n" +
+		"env [-p]       print environment (-p: include $PATH)\n" +
+		"install [dir]  install individual directory\n" +
+		"list [-json]   list all supported platforms\n" +
+		"test [-h]      run Go test(s)\n" +
+		"version        print Go version\n" +
+		"\n" +
+		"All commands take -v flags to emit extra information.\n",
+	)
+	xexit(2)
+}
+
 // cmdtab records the available commands.
 var cmdtab = []struct {
 	name string
@@ -26,6 +46,125 @@ var cmdtab = []struct {
 	{"version", cmdversion},
 }
 
+// main takes care of OS-specific startup and dispatches to xmain.
+func main() {
+	os.Setenv("TERM", "dumb") // disable escape codes in clang errors
+
+	// provide -check-armv6k first, before checking for $GOROOT so that
+	// it is possible to run this check without having $GOROOT available.
+	if len(os.Args) > 1 && os.Args[1] == "-check-armv6k" {
+		useARMv6K() // might fail with SIGILL
+		println("ARMv6K supported.")
+		os.Exit(0)
+	}
+
+	gohostos = runtime.GOOS
+	switch gohostos {
+	case "darwin":
+		// Even on 64-bit platform, darwin uname -m prints i386.
+		// We don't support any of the OS X versions that run on 32-bit-only hardware anymore.
+		gohostarch = "amd64"
+	case "freebsd":
+		// Since FreeBSD 10 gcc is no longer part of the base system.
+		defaultclang = true
+	case "solaris":
+		// Even on 64-bit platform, solaris uname -m prints i86pc.
+		out := run("", CheckExit, "isainfo", "-n")
+		if strings.Contains(out, "amd64") {
+			gohostarch = "amd64"
+		}
+		if strings.Contains(out, "i386") {
+			gohostarch = "386"
+		}
+	case "plan9":
+		gohostarch = os.Getenv("objtype")
+		if gohostarch == "" {
+			fatal("$objtype is unset")
+		}
+	case "windows":
+		exe = ".exe"
+	}
+
+	sysinit()
+
+	if gohostarch == "" {
+		// Default Unix system.
+		out := run("", CheckExit, "uname", "-m")
+		switch {
+		case strings.Contains(out, "x86_64"), strings.Contains(out, "amd64"):
+			gohostarch = "amd64"
+		case strings.Contains(out, "86"):
+			gohostarch = "386"
+		case strings.Contains(out, "arm"):
+			gohostarch = "arm"
+		case strings.Contains(out, "aarch64"):
+			gohostarch = "arm64"
+		case strings.Contains(out, "ppc64le"):
+			gohostarch = "ppc64le"
+		case strings.Contains(out, "ppc64"):
+			gohostarch = "ppc64"
+		case strings.Contains(out, "mips64"):
+			gohostarch = "mips64"
+			if elfIsLittleEndian(os.Args[0]) {
+				gohostarch = "mips64le"
+			}
+		case strings.Contains(out, "mips"):
+			gohostarch = "mips"
+			if elfIsLittleEndian(os.Args[0]) {
+				gohostarch = "mipsle"
+			}
+		case strings.Contains(out, "s390x"):
+			gohostarch = "s390x"
+		case gohostos == "darwin":
+			if strings.Contains(run("", CheckExit, "uname", "-v"), "RELEASE_ARM_") {
+				gohostarch = "arm"
+			}
+		default:
+			fatal("unknown architecture: %s", out)
+		}
+	}
+
+	if gohostarch == "arm" || gohostarch == "mips64" || gohostarch == "mips64le" {
+		maxbg = min(maxbg, runtime.NumCPU())
+	}
+	bginit()
+
+	// The OS X 10.6 linker does not support external linking mode.
+	// See golang.org/issue/5130.
+	//
+	// OS X 10.6 does not work with clang either, but OS X 10.9 requires it.
+	// It seems to work with OS X 10.8, so we default to clang for 10.8 and later.
+	// See golang.org/issue/5822.
+	//
+	// Roughly, OS X 10.N shows up as uname release (N+4),
+	// so OS X 10.6 is uname version 10 and OS X 10.8 is uname version 12.
+	if gohostos == "darwin" {
+		rel := run("", CheckExit, "uname", "-r")
+		if i := strings.Index(rel, "."); i >= 0 {
+			rel = rel[:i]
+		}
+		osx, _ := strconv.Atoi(rel)
+		if osx <= 6+4 {
+			goextlinkenabled = "0"
+		}
+		if osx >= 8+4 {
+			defaultclang = true
+		}
+	}
+
+	if len(os.Args) > 1 && os.Args[1] == "-check-goarm" {
+		useVFPv1() // might fail with SIGILL
+		println("VFPv1 OK.")
+		useVFPv3() // might fail with SIGILL
+		println("VFPv3 OK.")
+		os.Exit(0)
+	}
+
+	xinit()
+	xmain()
+	xexit(0)
+}
+
 // The OS-specific main calls into the portable code here.
 func xmain() {
 	if len(os.Args) < 2 {
@@ -44,44 +183,6 @@ func xmain() {
 			return
 		}
 	}
-
 	xprintf("unknown command %s\n", cmd)
 	usage()
 }
-
-func xflagparse(maxargs int) {
-	flag.Var((*count)(&vflag), "v", "verbosity")
-	flag.Parse()
-	if maxargs >= 0 && flag.NArg() > maxargs {
-		flag.Usage()
-	}
-}
-
-// 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) IsBoolFlag() bool {
-	return true
-}

src/cmd/dist/util.go

@@ -6,13 +6,13 @@ package main
 
 import (
 	"bytes"
+	"flag"
 	"fmt"
 	"io"
 	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
-	"runtime"
 	"sort"
 	"strconv"
 	"strings"
@@ -372,125 +372,6 @@ func errprintf(format string, args ...interface{}) {
 	fmt.Fprintf(os.Stderr, format, args...)
 }
 
-// main takes care of OS-specific startup and dispatches to xmain.
-func main() {
-	os.Setenv("TERM", "dumb") // disable escape codes in clang errors
-
-	// provide -check-armv6k first, before checking for $GOROOT so that
-	// it is possible to run this check without having $GOROOT available.
-	if len(os.Args) > 1 && os.Args[1] == "-check-armv6k" {
-		useARMv6K() // might fail with SIGILL
-		println("ARMv6K supported.")
-		os.Exit(0)
-	}
-
-	gohostos = runtime.GOOS
-	switch gohostos {
-	case "darwin":
-		// Even on 64-bit platform, darwin uname -m prints i386.
-		// We don't support any of the OS X versions that run on 32-bit-only hardware anymore.
-		gohostarch = "amd64"
-	case "freebsd":
-		// Since FreeBSD 10 gcc is no longer part of the base system.
-		defaultclang = true
-	case "solaris":
-		// Even on 64-bit platform, solaris uname -m prints i86pc.
-		out := run("", CheckExit, "isainfo", "-n")
-		if strings.Contains(out, "amd64") {
-			gohostarch = "amd64"
-		}
-		if strings.Contains(out, "i386") {
-			gohostarch = "386"
-		}
-	case "plan9":
-		gohostarch = os.Getenv("objtype")
-		if gohostarch == "" {
-			fatal("$objtype is unset")
-		}
-	case "windows":
-		exe = ".exe"
-	}
-
-	sysinit()
-
-	if gohostarch == "" {
-		// Default Unix system.
-		out := run("", CheckExit, "uname", "-m")
-		switch {
-		case strings.Contains(out, "x86_64"), strings.Contains(out, "amd64"):
-			gohostarch = "amd64"
-		case strings.Contains(out, "86"):
-			gohostarch = "386"
-		case strings.Contains(out, "arm"):
-			gohostarch = "arm"
-		case strings.Contains(out, "aarch64"):
-			gohostarch = "arm64"
-		case strings.Contains(out, "ppc64le"):
-			gohostarch = "ppc64le"
-		case strings.Contains(out, "ppc64"):
-			gohostarch = "ppc64"
-		case strings.Contains(out, "mips64"):
-			gohostarch = "mips64"
-			if elfIsLittleEndian(os.Args[0]) {
-				gohostarch = "mips64le"
-			}
-		case strings.Contains(out, "mips"):
-			gohostarch = "mips"
-			if elfIsLittleEndian(os.Args[0]) {
-				gohostarch = "mipsle"
-			}
-		case strings.Contains(out, "s390x"):
-			gohostarch = "s390x"
-		case gohostos == "darwin":
-			if strings.Contains(run("", CheckExit, "uname", "-v"), "RELEASE_ARM_") {
-				gohostarch = "arm"
-			}
-		default:
-			fatal("unknown architecture: %s", out)
-		}
-	}
-
-	if gohostarch == "arm" || gohostarch == "mips64" || gohostarch == "mips64le" {
-		maxbg = min(maxbg, runtime.NumCPU())
-	}
-	bginit()
-
-	// The OS X 10.6 linker does not support external linking mode.
-	// See golang.org/issue/5130.
-	//
-	// OS X 10.6 does not work with clang either, but OS X 10.9 requires it.
-	// It seems to work with OS X 10.8, so we default to clang for 10.8 and later.
-	// See golang.org/issue/5822.
-	//
-	// Roughly, OS X 10.N shows up as uname release (N+4),
-	// so OS X 10.6 is uname version 10 and OS X 10.8 is uname version 12.
-	if gohostos == "darwin" {
-		rel := run("", CheckExit, "uname", "-r")
-		if i := strings.Index(rel, "."); i >= 0 {
-			rel = rel[:i]
-		}
-		osx, _ := strconv.Atoi(rel)
-		if osx <= 6+4 {
-			goextlinkenabled = "0"
-		}
-		if osx >= 8+4 {
-			defaultclang = true
-		}
-	}
-
-	if len(os.Args) > 1 && os.Args[1] == "-check-goarm" {
-		useVFPv1() // might fail with SIGILL
-		println("VFPv1 OK.")
-		useVFPv3() // might fail with SIGILL
-		println("VFPv3 OK.")
-		os.Exit(0)
-	}
-
-	xinit()
-	xmain()
-	xexit(0)
-}
-
 // xsamefile reports whether f1 and f2 are the same file (or dir)
 func xsamefile(f1, f2 string) bool {
 	fi1, err1 := os.Stat(f1)
@@ -569,3 +450,40 @@ func elfIsLittleEndian(fn string) bool {
 	}
 	panic("unreachable")
 }
+
+// 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) IsBoolFlag() bool {
+	return true
+}
+
+func xflagparse(maxargs int) {
+	flag.Var((*count)(&vflag), "v", "verbosity")
+	flag.Parse()
+	if maxargs >= 0 && flag.NArg() > maxargs {
+		flag.Usage()
+	}
+}