all: retire architecture letter in file names, public API

This CL removes the remaining visible uses of the "architecture letter" concept.
(They are no longer in tool names nor in source directory names.)

Because the architecture letter concept is now gone, delete GOCHAR
from "go env" output, and change go/build.ArchChar to return an
error always.

The architecture letter is still used in the compiler and linker sources
as a clumsy architecture enumeration, but that use is not visible to
Go users and can be cleaned up separately.

Change-Id: I4d97a38f372003fb610c9c5241bea440d9dbeb8d
Reviewed-on: https://go-review.googlesource.com/10289
Reviewed-by: Rob Pike <r@golang.org>

11 files changed, 51 insertions, 130 deletions

diff --git a/src/cmd/asm/internal/flags/flags.go b/src/cmd/asm/internal/flags/flags.go
index c74f26974a..bf5cb1eef3 100644
--- a/src/cmd/asm/internal/flags/flags.go
+++ b/src/cmd/asm/internal/flags/flags.go
@@ -51,7 +51,7 @@ func Usage() {
 	os.Exit(2)
 }
 
-func Parse(theChar int) {
+func Parse() {
 	flag.Usage = Usage
 	flag.Parse()
 	if flag.NArg() != 1 {
@@ -64,6 +64,6 @@ func Parse(theChar int) {
 		if strings.HasSuffix(input, ".s") {
 			input = input[:len(input)-2]
 		}
-		*OutputFile = fmt.Sprintf("%s.%c", input, theChar)
+		*OutputFile = fmt.Sprintf("%s.o", input)
 	}
 }
diff --git a/src/cmd/asm/main.go b/src/cmd/asm/main.go
index 32bdee6624..db0e28e2e5 100644
--- a/src/cmd/asm/main.go
+++ b/src/cmd/asm/main.go
@@ -29,7 +29,7 @@ func main() {
 		log.Fatalf("asm: unrecognized architecture %s", GOARCH)
 	}
 
-	flags.Parse(architecture.Thechar)
+	flags.Parse()
 
 	// Create object file, write header.
 	fd, err := os.Create(*flags.OutputFile)
diff --git a/src/cmd/compile/internal/gc/lex.go b/src/cmd/compile/internal/gc/lex.go
index f9211407fb..3b93207ef1 100644
--- a/src/cmd/compile/internal/gc/lex.go
+++ b/src/cmd/compile/internal/gc/lex.go
@@ -583,7 +583,7 @@ func findpkg(name string) (file string, ok bool) {
 		if obj.Access(file, 0) >= 0 {
 			return file, true
 		}
-		file = fmt.Sprintf("%s.%c", name, Thearch.Thechar)
+		file = fmt.Sprintf("%s.o", name)
 		if obj.Access(file, 0) >= 0 {
 			return file, true
 		}
@@ -605,7 +605,7 @@ func findpkg(name string) (file string, ok bool) {
 		if obj.Access(file, 0) >= 0 {
 			return file, true
 		}
-		file = fmt.Sprintf("%s/%s.%c", p.dir, name, Thearch.Thechar)
+		file = fmt.Sprintf("%s/%s.o", p.dir, name)
 		if obj.Access(file, 0) >= 0 {
 			return file, true
 		}
@@ -626,7 +626,7 @@ func findpkg(name string) (file string, ok bool) {
 		if obj.Access(file, 0) >= 0 {
 			return file, true
 		}
-		file = fmt.Sprintf("%s/pkg/%s_%s%s%s/%s.%c", goroot, goos, goarch, suffixsep, suffix, name, Thearch.Thechar)
+		file = fmt.Sprintf("%s/pkg/%s_%s%s%s/%s.o", goroot, goos, goarch, suffixsep, suffix, name)
 		if obj.Access(file, 0) >= 0 {
 			return file, true
 		}
@@ -637,7 +637,7 @@ func findpkg(name string) (file string, ok bool) {
 
 func fakeimport() {
 	importpkg = mkpkg("fake")
-	cannedimports("fake.6", "$$\n")
+	cannedimports("fake.o", "$$\n")
 }
 
 func importfile(f *Val, line int) {
@@ -679,7 +679,7 @@ func importfile(f *Val, line int) {
 		}
 
 		importpkg = mkpkg(f.U.(string))
-		cannedimports("unsafe.6", unsafeimport)
+		cannedimports("unsafe.o", unsafeimport)
 		imported_unsafe = 1
 		return
 	}
@@ -2596,6 +2596,6 @@ func mkpackage(pkgname string) {
 		if i := strings.LastIndex(p, "."); i >= 0 {
 			p = p[:i]
 		}
-		outfile = fmt.Sprintf("%s.%c", p, Thearch.Thechar)
+		outfile = fmt.Sprintf("%s.o", p)
 	}
 }
diff --git a/src/cmd/compile/internal/gc/mkbuiltin.go b/src/cmd/compile/internal/gc/mkbuiltin.go
index b2362a6f01..f4569b48c2 100644
--- a/src/cmd/compile/internal/gc/mkbuiltin.go
+++ b/src/cmd/compile/internal/gc/mkbuiltin.go
@@ -13,21 +13,14 @@ package main
 import (
 	"bufio"
 	"fmt"
-	"go/build"
 	"io"
 	"log"
 	"os"
 	"os/exec"
-	"runtime"
 	"strings"
 )
 
 func main() {
-	gochar, err := build.ArchChar(runtime.GOARCH)
-	if err != nil {
-		log.Fatal(err)
-	}
-
 	f, err := os.Create("builtin.go")
 	if err != nil {
 		log.Fatal(err)
@@ -40,7 +33,7 @@ func main() {
 	fmt.Fprintln(w, "package gc")
 
 	for _, name := range os.Args[1:] {
-		mkbuiltin(w, gochar, name)
+		mkbuiltin(w, name)
 	}
 
 	if err := w.Flush(); err != nil {
@@ -49,11 +42,11 @@ func main() {
 }
 
 // Compile .go file, import data from .6 file, and write Go string version.
-func mkbuiltin(w io.Writer, gochar string, name string) {
-	if err := exec.Command("go", "tool", gochar+"g", "-A", "builtin/"+name+".go").Run(); err != nil {
+func mkbuiltin(w io.Writer, name string) {
+	if err := exec.Command("go", "tool", "compile", "-A", "builtin/"+name+".go").Run(); err != nil {
 		log.Fatal(err)
 	}
-	obj := fmt.Sprintf("%s.%s", name, gochar)
+	obj := "name.o"
 	defer os.Remove(obj)
 
 	r, err := os.Open(obj)
@@ -77,7 +70,7 @@ Begin:
 	fmt.Fprintf(w, "\nconst %simport = \"\" +\n", name)
 
 	// sys.go claims to be in package PACKAGE to avoid
-	// conflicts during "6g sys.go".  Rename PACKAGE to $2.
+	// conflicts during "go tool compile sys.go".  Rename PACKAGE to $2.
 	replacer := strings.NewReplacer("PACKAGE", name)
 
 	// Process imports, stopping at $$ that closes them.
diff --git a/src/cmd/compile/internal/gc/obj.go b/src/cmd/compile/internal/gc/obj.go
index 2afd786dc1..9bb334ca34 100644
--- a/src/cmd/compile/internal/gc/obj.go
+++ b/src/cmd/compile/internal/gc/obj.go
@@ -102,8 +102,7 @@ func dumpobj() {
 			obj.Bputc(bout, 0)
 		}
 		obj.Bseek(bout, startobj-ArhdrSize, 0)
-		name := fmt.Sprintf("_go_.%c", Thearch.Thechar)
-		formathdr(arhdr[:], name, size)
+		formathdr(arhdr[:], "_go_.o", size)
 		bout.Write(arhdr[:])
 	}
 
diff --git a/src/cmd/dist/build.go b/src/cmd/dist/build.go
index d6cfaf02cb..0cdb7d69f7 100644
--- a/src/cmd/dist/build.go
+++ b/src/cmd/dist/build.go
@@ -20,7 +20,6 @@ var (
 	goarch           string
 	gobin            string
 	gohostarch       string
-	gohostchar       string
 	gohostos         string
 	goos             string
 	goarm            string
@@ -30,10 +29,8 @@ var (
 	goextlinkenabled string
 	workdir          string
 	tooldir          string
-	gochar           string
 	oldgoos          string
 	oldgoarch        string
-	oldgochar        string
 	slash            string
 	exe              string
 	defaultcc        string
@@ -48,17 +45,13 @@ var (
 	vflag int  // verbosity
 )
 
-// The known architecture letters.
-var gochars = "5667899"
-
 // The known architectures.
 var okgoarch = []string{
-	// same order as gochars
-	"arm",
+	"386",
 	"amd64",
 	"amd64p32",
+	"arm",
 	"arm64",
-	"386",
 	"ppc64",
 	"ppc64le",
 }
@@ -147,22 +140,18 @@ func xinit() {
 		gohostarch = b
 	}
 
-	i := find(gohostarch, okgoarch)
-	if i < 0 {
+	if find(gohostarch, okgoarch) < 0 {
 		fatal("unknown $GOHOSTARCH %s", gohostarch)
 	}
-	gohostchar = gochars[i : i+1]
 
 	b = os.Getenv("GOARCH")
 	if b == "" {
 		b = gohostarch
 	}
 	goarch = b
-	i = find(goarch, okgoarch)
-	if i < 0 {
+	if find(goarch, okgoarch) < 0 {
 		fatal("unknown $GOARCH %s", goarch)
 	}
-	gochar = gochars[i : i+1]
 
 	b = os.Getenv("GO_EXTLINK_ENABLED")
 	if b != "" {
@@ -436,7 +425,7 @@ func setup() {
 	}
 
 	// If $GOBIN is set and has a Go compiler, it must be cleaned.
-	for _, char := range gochars {
+	for _, char := range "56789" {
 		if isfile(pathf("%s%s%c%s", gobin, slash, char, "g")) {
 			for _, old := range oldtool {
 				xremove(pathf("%s/%s", gobin, old))
@@ -703,11 +692,7 @@ func install(dir string) {
 		b := pathf("%s/%s", workdir, filepath.Base(p))
 
 		// Change the last character of the output file (which was c or s).
-		if gohostos == "plan9" {
-			b = b[:len(b)-1] + gohostchar
-		} else {
-			b = b[:len(b)-1] + "o"
-		}
+		b = b[:len(b)-1] + "o"
 		compile = append(compile, "-o", b, p)
 		bgrun(path, compile...)
 
@@ -1035,7 +1020,6 @@ func cmdenv() {
 	xprintf(format, "GOHOSTARCH", gohostarch)
 	xprintf(format, "GOHOSTOS", gohostos)
 	xprintf(format, "GOTOOLDIR", tooldir)
-	xprintf(format, "GOCHAR", gochar)
 	if goarch == "arm" {
 		xprintf(format, "GOARM", goarm)
 	}
@@ -1080,10 +1064,8 @@ func cmdbootstrap() {
 	// For the main bootstrap, building for host os/arch.
 	oldgoos = goos
 	oldgoarch = goarch
-	oldgochar = gochar
 	goos = gohostos
 	goarch = gohostarch
-	gochar = gohostchar
 	os.Setenv("GOHOSTARCH", gohostarch)
 	os.Setenv("GOHOSTOS", gohostos)
 	os.Setenv("GOARCH", goarch)
@@ -1097,37 +1079,22 @@ func cmdbootstrap() {
 	// than in a standard release like Go 1.4, so don't do this rebuild by default.
 	if false {
 		xprintf("##### Building Go toolchain using itself.\n")
-		for _, pattern := range buildorder {
-			if pattern == "cmd/go" {
+		for _, dir := range buildorder {
+			if dir == "cmd/go" {
 				break
 			}
-			dir := pattern
-			if strings.Contains(pattern, "%s") {
-				dir = fmt.Sprintf(pattern, gohostchar)
-			}
 			install(dir)
-			if oldgochar != gohostchar && strings.Contains(pattern, "%s") {
-				install(fmt.Sprintf(pattern, oldgochar))
-			}
 		}
 		xprintf("\n")
 	}
 
 	xprintf("##### Building compilers and go_bootstrap for host, %s/%s.\n", gohostos, gohostarch)
-	for _, pattern := range buildorder {
-		dir := pattern
-		if strings.Contains(pattern, "%s") {
-			dir = fmt.Sprintf(pattern, gohostchar)
-		}
+	for _, dir := range buildorder {
 		install(dir)
-		if oldgochar != gohostchar && strings.Contains(pattern, "%s") {
-			install(fmt.Sprintf(pattern, oldgochar))
-		}
 	}
 
 	goos = oldgoos
 	goarch = oldgoarch
-	gochar = oldgochar
 	os.Setenv("GOARCH", goarch)
 	os.Setenv("GOOS", goos)
 
diff --git a/src/cmd/go/build.go b/src/cmd/go/build.go
index aa9a408eff..17ff7e0cbb 100644
--- a/src/cmd/go/build.go
+++ b/src/cmd/go/build.go
@@ -547,9 +547,6 @@ var (
 	goarch    string
 	goos      string
 	exeSuffix string
-
-	archCharVal string
-	archCharErr error
 )
 
 func init() {
@@ -558,16 +555,6 @@ func init() {
 	if goos == "windows" {
 		exeSuffix = ".exe"
 	}
-	archCharVal, archCharErr = build.ArchChar(goarch)
-}
-
-// archChar returns the architecture character.  This is only needed
-// for the gc toolchain, so only fail if we actually need it.
-func archChar() string {
-	if archCharErr != nil {
-		fatalf("%s", archCharErr)
-	}
-	return archCharVal
 }
 
 // A builder holds global state about a build.
@@ -1208,7 +1195,7 @@ func (b *builder) build(a *action) (err error) {
 		fmt.Fprintf(os.Stderr, "%s\n", a.p.ImportPath)
 	}
 
-	if a.p.Standard && a.p.ImportPath == "runtime" && buildContext.Compiler == "gc" && archChar() != "" &&
+	if a.p.Standard && a.p.ImportPath == "runtime" && buildContext.Compiler == "gc" &&
 		(!hasString(a.p.GoFiles, "zgoos_"+buildContext.GOOS+".go") ||
 			!hasString(a.p.GoFiles, "zgoarch_"+buildContext.GOARCH+".go")) {
 		return fmt.Errorf("%s/%s must be bootstrapped using make%v", buildContext.GOOS, buildContext.GOARCH, defaultSuffix())
@@ -1371,15 +1358,8 @@ func (b *builder) build(a *action) (err error) {
 		}
 	}
 
-	var objExt string
-	if _, ok := buildToolchain.(gccgoToolchain); ok {
-		objExt = "o"
-	} else {
-		objExt = archChar()
-	}
-
 	for _, file := range cfiles {
-		out := file[:len(file)-len(".c")] + "." + objExt
+		out := file[:len(file)-len(".c")] + ".o"
 		if err := buildToolchain.cc(b, a.p, obj, obj+out, file); err != nil {
 			return err
 		}
@@ -1388,7 +1368,7 @@ func (b *builder) build(a *action) (err error) {
 
 	// Assemble .s files.
 	for _, file := range sfiles {
-		out := file[:len(file)-len(".s")] + "." + objExt
+		out := file[:len(file)-len(".s")] + ".o"
 		if err := buildToolchain.asm(b, a.p, obj, obj+out, file); err != nil {
 			return err
 		}
@@ -2120,7 +2100,7 @@ func (gcToolchain) gc(b *builder, p *Package, archive, obj string, asmhdr bool,
 	if archive != "" {
 		ofile = archive
 	} else {
-		out := "_go_." + archChar()
+		out := "_go_.o"
 		ofile = obj + out
 	}
 
@@ -2182,9 +2162,22 @@ func (gcToolchain) asm(b *builder, p *Package, obj, ofile, sfile string) error {
 	}
 	// Disable checks when additional flags are passed, as the old assemblers
 	// don't implement some of them (e.g., -shared).
-	if verifyAsm && goarch != "arm64" && len(buildAsmflags) == 0 {
-		if err := toolVerify(b, p, "old"+archChar()+"a", ofile, args); err != nil {
-			return err
+	if verifyAsm && len(buildAsmflags) == 0 {
+		old := ""
+		switch goarch {
+		case "arm":
+			old = "old5a"
+		case "amd64", "amd64p32":
+			old = "old6a"
+		case "386":
+			old = "old8a"
+		case "ppc64", "ppc64le":
+			old = "old9a"
+		}
+		if old != "" {
+			if err := toolVerify(b, p, old, ofile, args); err != nil {
+				return err
+			}
 		}
 	}
 	return nil
@@ -2785,13 +2778,6 @@ func (b *builder) cgo(p *Package, cgoExe, obj string, pcCFLAGS, pcLDFLAGS, cgofi
 	cgoflags := []string{}
 	// TODO: make cgo not depend on $GOARCH?
 
-	var objExt string
-	if _, ok := buildToolchain.(gccgoToolchain); ok {
-		objExt = "o"
-	} else {
-		objExt = archChar()
-	}
-
 	if p.Standard && p.ImportPath == "runtime/cgo" {
 		cgoflags = append(cgoflags, "-import_runtime_cgo=false")
 	}
@@ -2836,7 +2822,7 @@ func (b *builder) cgo(p *Package, cgoExe, obj string, pcCFLAGS, pcLDFLAGS, cgofi
 	// cc _cgo_defun.c
 	_, gccgo := buildToolchain.(gccgoToolchain)
 	if gccgo {
-		defunObj := obj + "_cgo_defun." + objExt
+		defunObj := obj + "_cgo_defun.o"
 		if err := buildToolchain.cc(b, p, obj, defunObj, defunC); err != nil {
 			return nil, nil, err
 		}
diff --git a/src/cmd/go/env.go b/src/cmd/go/env.go
index 863eb4d26e..8d427b37c2 100644
--- a/src/cmd/go/env.go
+++ b/src/cmd/go/env.go
@@ -49,10 +49,6 @@ func mkEnv() []envVar {
 		{"TERM", "dumb"},
 	}
 
-	if archCharErr == nil {
-		env = append(env, envVar{"GOCHAR", archChar()})
-	}
-
 	if goos != "plan9" {
 		cmd := b.gccCmd(".")
 		env = append(env, envVar{"CC", cmd[0]})
diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go
index a36cd0f8f4..6cf0b525e5 100644
--- a/src/cmd/link/internal/ld/lib.go
+++ b/src/cmd/link/internal/ld/lib.go
@@ -1627,7 +1627,7 @@ func Cput(c uint8) {
 }
 
 func usage() {
-	fmt.Fprintf(os.Stderr, "usage: %cl [options] obj.%c\n", Thearch.Thechar, Thearch.Thechar)
+	fmt.Fprintf(os.Stderr, "usage: link [options] main.o\n")
 	obj.Flagprint(2)
 	Exit(2)
 }
diff --git a/src/cmd/link/internal/ld/pobj.go b/src/cmd/link/internal/ld/pobj.go
index 8568744c3d..5b24428059 100644
--- a/src/cmd/link/internal/ld/pobj.go
+++ b/src/cmd/link/internal/ld/pobj.go
@@ -160,10 +160,9 @@ func Ldmain() {
 	}
 
 	if outfile == "" {
+		outfile = "a.out"
 		if HEADTYPE == obj.Hwindows {
-			outfile = fmt.Sprintf("%c.out.exe", Thearch.Thechar)
-		} else {
-			outfile = fmt.Sprintf("%c.out", Thearch.Thechar)
+			outfile += ".exe"
 		}
 	}
 
diff --git a/src/cmd/pack/pack_test.go b/src/cmd/pack/pack_test.go
index 97992059b9..cd32020501 100644
--- a/src/cmd/pack/pack_test.go
+++ b/src/cmd/pack/pack_test.go
@@ -13,7 +13,6 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
-	"regexp"
 	"runtime"
 	"testing"
 	"time"
@@ -223,15 +222,13 @@ func TestHello(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	char := findChar(t, dir)
-
 	run := func(args ...string) string {
 		return doRun(t, dir, args...)
 	}
 
 	run("go", "build", "cmd/pack") // writes pack binary to dir
 	run("go", "tool", "compile", "hello.go")
-	run("./pack", "grc", "hello.a", "hello."+char)
+	run("./pack", "grc", "hello.a", "hello.o")
 	run("go", "tool", "link", "-o", "a.out", "hello.a")
 	out := run("./a.out")
 	if out != "hello world\n" {
@@ -297,17 +294,15 @@ func TestLargeDefs(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	char := findChar(t, dir)
-
 	run := func(args ...string) string {
 		return doRun(t, dir, args...)
 	}
 
 	run("go", "build", "cmd/pack") // writes pack binary to dir
 	run("go", "tool", "compile", "large.go")
-	run("./pack", "grc", "large.a", "large."+char)
+	run("./pack", "grc", "large.a", "large.o")
 	run("go", "tool", "compile", "-I", ".", "main.go")
-	run("go", "tool", "link", "-L", ".", "-o", "a.out", "main."+char)
+	run("go", "tool", "link", "-L", ".", "-o", "a.out", "main.o")
 	out := run("./a.out")
 	if out != "ok\n" {
 		t.Fatalf("incorrect output: %q, want %q", out, "ok\n")
@@ -325,20 +320,6 @@ func doRun(t *testing.T, dir string, args ...string) string {
 	return string(out)
 }
 
-// findChar returns the architecture character for the go command.
-func findChar(t *testing.T, dir string) string {
-	out := doRun(t, dir, "go", "env")
-	re, err := regexp.Compile(`\s*GOCHAR=['"]?(\w)['"]?`)
-	if err != nil {
-		t.Fatal(err)
-	}
-	fields := re.FindStringSubmatch(out)
-	if fields == nil {
-		t.Fatal("cannot find GOCHAR in 'go env' output:\n", out)
-	}
-	return fields[1]
-}
-
 // Fake implementation of files.
 
 var helloFile = &FakeFile{