src/internal/buildcfg/cfg.go - toolchain/go - Git at Google

 // Copyright 2021 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 buildcfg provides access to the build configuration
 // described by the current environment. It is for use by build tools
 // such as cmd/go or cmd/compile and for setting up go/build's Default context.
 //
 // Note that it does NOT provide access to the build configuration used to
 // build the currently-running binary. For that, use runtime.GOOS etc
 // as well as internal/goexperiment.
 package buildcfg

 import (
 	"fmt"
 	"os"
 	"path/filepath"
 	"runtime"
 	"strconv"
 	"strings"
 )

 var (
 	GOROOT   = runtime.GOROOT() // cached for efficiency
 	GOARCH   = envOr("GOARCH", defaultGOARCH)
 	GOOS     = envOr("GOOS", defaultGOOS)
 	GO386    = envOr("GO386", defaultGO386)
 	GOAMD64  = goamd64()
 	GOARM    = goarm()
 	GOMIPS   = gomips()
 	GOMIPS64 = gomips64()
 	GOPPC64  = goppc64()
 	GOWASM   = gowasm()
 	ToolTags = toolTags()
 	GO_LDSO  = defaultGO_LDSO
 	Version  = version
 )

 // Error is one of the errors found (if any) in the build configuration.
 var Error error

 // Check exits the program with a fatal error if Error is non-nil.
 func Check() {
 	if Error != nil {
 		fmt.Fprintf(os.Stderr, "%s: %v\n", filepath.Base(os.Args[0]), Error)
 		os.Exit(2)
 	}
 }

 func envOr(key, value string) string {
 	if x := os.Getenv(key); x != "" {
 		return x
 	}
 	return value
 }

 func goamd64() int {
 	switch v := envOr("GOAMD64", defaultGOAMD64); v {
 	case "v1":
 		return 1
 	case "v2":
 		return 2
 	case "v3":
 		return 3
 	case "v4":
 		return 4
 	}
 	Error = fmt.Errorf("invalid GOAMD64: must be v1, v2, v3, v4")
 	return int(defaultGOAMD64[len("v")] - '0')
 }

 type goarmFeatures struct {
 	Version   int
 	SoftFloat bool
 }

 func (g goarmFeatures) String() string {
 	armStr := strconv.Itoa(g.Version)
 	if g.SoftFloat {
 		armStr += ",softfloat"
 	} else {
 		armStr += ",hardfloat"
 	}
 	return armStr
 }

 func goarm() (g goarmFeatures) {
 	const (
 		softFloatOpt = ",softfloat"
 		hardFloatOpt = ",hardfloat"
 	)
 	def := defaultGOARM
 	if GOOS == "android" && GOARCH == "arm" {
 		// Android arm devices always support GOARM=7.
 		def = "7"
 	}
 	v := envOr("GOARM", def)

 	floatSpecified := false
 	if strings.HasSuffix(v, softFloatOpt) {
 		g.SoftFloat = true
 		floatSpecified = true
 		v = v[:len(v)-len(softFloatOpt)]
 	}
 	if strings.HasSuffix(v, hardFloatOpt) {
 		floatSpecified = true
 		v = v[:len(v)-len(hardFloatOpt)]
 	}

 	switch v {
 	case "5":
 		g.Version = 5
 	case "6":
 		g.Version = 6
 	case "7":
 		g.Version = 7
 	default:
 		Error = fmt.Errorf("invalid GOARM: must start with 5, 6, or 7, and may optionally end in either %q or %q", hardFloatOpt, softFloatOpt)
 		g.Version = int(def[0] - '0')
 	}

 	// 5 defaults to softfloat. 6 and 7 default to hardfloat.
 	if !floatSpecified && g.Version == 5 {
 		g.SoftFloat = true
 	}
 	return
 }

 func gomips() string {
 	switch v := envOr("GOMIPS", defaultGOMIPS); v {
 	case "hardfloat", "softfloat":
 		return v
 	}
 	Error = fmt.Errorf("invalid GOMIPS: must be hardfloat, softfloat")
 	return defaultGOMIPS
 }

 func gomips64() string {
 	switch v := envOr("GOMIPS64", defaultGOMIPS64); v {
 	case "hardfloat", "softfloat":
 		return v
 	}
 	Error = fmt.Errorf("invalid GOMIPS64: must be hardfloat, softfloat")
 	return defaultGOMIPS64
 }

 func goppc64() int {
 	switch v := envOr("GOPPC64", defaultGOPPC64); v {
 	case "power8":
 		return 8
 	case "power9":
 		return 9
 	case "power10":
 		return 10
 	}
 	Error = fmt.Errorf("invalid GOPPC64: must be power8, power9, power10")
 	return int(defaultGOPPC64[len("power")] - '0')
 }

 type gowasmFeatures struct {
 	SatConv bool
 	SignExt bool
 }

 func (f gowasmFeatures) String() string {
 	var flags []string
 	if f.SatConv {
 		flags = append(flags, "satconv")
 	}
 	if f.SignExt {
 		flags = append(flags, "signext")
 	}
 	return strings.Join(flags, ",")
 }

 func gowasm() (f gowasmFeatures) {
 	for _, opt := range strings.Split(envOr("GOWASM", ""), ",") {
 		switch opt {
 		case "satconv":
 			f.SatConv = true
 		case "signext":
 			f.SignExt = true
 		case "":
 			// ignore
 		default:
 			Error = fmt.Errorf("invalid GOWASM: no such feature %q", opt)
 		}
 	}
 	return
 }

 func Getgoextlinkenabled() string {
 	return envOr("GO_EXTLINK_ENABLED", defaultGO_EXTLINK_ENABLED)
 }

 func toolTags() []string {
 	tags := experimentTags()
 	tags = append(tags, gogoarchTags()...)
 	return tags
 }

 func experimentTags() []string {
 	var list []string
 	// For each experiment that has been enabled in the toolchain, define a
 	// build tag with the same name but prefixed by "goexperiment." which can be
 	// used for compiling alternative files for the experiment. This allows
 	// changes for the experiment, like extra struct fields in the runtime,
 	// without affecting the base non-experiment code at all.
 	for _, exp := range Experiment.Enabled() {
 		list = append(list, "goexperiment."+exp)
 	}
 	return list
 }

 // GOGOARCH returns the name and value of the GO$GOARCH setting.
 // For example, if GOARCH is "amd64" it might return "GOAMD64", "v2".
 func GOGOARCH() (name, value string) {
 	switch GOARCH {
 	case "386":
 		return "GO386", GO386
 	case "amd64":
 		return "GOAMD64", fmt.Sprintf("v%d", GOAMD64)
 	case "arm":
 		return "GOARM", GOARM.String()
 	case "mips", "mipsle":
 		return "GOMIPS", GOMIPS
 	case "mips64", "mips64le":
 		return "GOMIPS64", GOMIPS64
 	case "ppc64", "ppc64le":
 		return "GOPPC64", fmt.Sprintf("power%d", GOPPC64)
 	case "wasm":
 		return "GOWASM", GOWASM.String()
 	}
 	return "", ""
 }

 func gogoarchTags() []string {
 	switch GOARCH {
 	case "386":
 		return []string{GOARCH + "." + GO386}
 	case "amd64":
 		var list []string
 		for i := 1; i <= GOAMD64; i++ {
 			list = append(list, fmt.Sprintf("%s.v%d", GOARCH, i))
 		}
 		return list
 	case "arm":
 		var list []string
 		for i := 5; i <= GOARM.Version; i++ {
 			list = append(list, fmt.Sprintf("%s.%d", GOARCH, i))
 		}
 		return list
 	case "mips", "mipsle":
 		return []string{GOARCH + "." + GOMIPS}
 	case "mips64", "mips64le":
 		return []string{GOARCH + "." + GOMIPS64}
 	case "ppc64", "ppc64le":
 		var list []string
 		for i := 8; i <= GOPPC64; i++ {
 			list = append(list, fmt.Sprintf("%s.power%d", GOARCH, i))
 		}
 		return list
 	case "wasm":
 		var list []string
 		if GOWASM.SatConv {
 			list = append(list, GOARCH+".satconv")
 		}
 		if GOWASM.SignExt {
 			list = append(list, GOARCH+".signext")
 		}
 		return list
 	}
 	return nil
 }
	// Copyright 2021 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 buildcfg provides access to the build configuration
	// described by the current environment. It is for use by build tools
	// such as cmd/go or cmd/compile and for setting up go/build's Default context.
	//
	// Note that it does NOT provide access to the build configuration used to
	// build the currently-running binary. For that, use runtime.GOOS etc
	// as well as internal/goexperiment.
	package buildcfg

	import (
	"fmt"
	"os"
	"path/filepath"
	"runtime"
	"strconv"
	"strings"
	)

	var (
	GOROOT = runtime.GOROOT() // cached for efficiency
	GOARCH = envOr("GOARCH", defaultGOARCH)
	GOOS = envOr("GOOS", defaultGOOS)
	GO386 = envOr("GO386", defaultGO386)
	GOAMD64 = goamd64()
	GOARM = goarm()
	GOMIPS = gomips()
	GOMIPS64 = gomips64()
	GOPPC64 = goppc64()
	GOWASM = gowasm()
	ToolTags = toolTags()
	GO_LDSO = defaultGO_LDSO
	Version = version
	)

	// Error is one of the errors found (if any) in the build configuration.
	var Error error

	// Check exits the program with a fatal error if Error is non-nil.
	func Check() {
	if Error != nil {
	fmt.Fprintf(os.Stderr, "%s: %v\n", filepath.Base(os.Args[0]), Error)
	os.Exit(2)
	}
	}

	func envOr(key, value string) string {
	if x := os.Getenv(key); x != "" {
	return x
	}
	return value
	}

	func goamd64() int {
	switch v := envOr("GOAMD64", defaultGOAMD64); v {
	case "v1":
	return 1
	case "v2":
	return 2
	case "v3":
	return 3
	case "v4":
	return 4
	}
	Error = fmt.Errorf("invalid GOAMD64: must be v1, v2, v3, v4")
	return int(defaultGOAMD64[len("v")] - '0')
	}

	type goarmFeatures struct {
	Version int
	SoftFloat bool
	}

	func (g goarmFeatures) String() string {
	armStr := strconv.Itoa(g.Version)
	if g.SoftFloat {
	armStr += ",softfloat"
	} else {
	armStr += ",hardfloat"
	}
	return armStr
	}

	func goarm() (g goarmFeatures) {
	const (
	softFloatOpt = ",softfloat"
	hardFloatOpt = ",hardfloat"
	)
	def := defaultGOARM
	if GOOS == "android" && GOARCH == "arm" {
	// Android arm devices always support GOARM=7.
	def = "7"
	}
	v := envOr("GOARM", def)

	floatSpecified := false
	if strings.HasSuffix(v, softFloatOpt) {
	g.SoftFloat = true
	floatSpecified = true
	v = v[:len(v)-len(softFloatOpt)]
	}
	if strings.HasSuffix(v, hardFloatOpt) {
	floatSpecified = true
	v = v[:len(v)-len(hardFloatOpt)]
	}

	switch v {
	case "5":
	g.Version = 5
	case "6":
	g.Version = 6
	case "7":
	g.Version = 7
	default:
	Error = fmt.Errorf("invalid GOARM: must start with 5, 6, or 7, and may optionally end in either %q or %q", hardFloatOpt, softFloatOpt)
	g.Version = int(def[0] - '0')
	}

	// 5 defaults to softfloat. 6 and 7 default to hardfloat.
	if !floatSpecified && g.Version == 5 {
	g.SoftFloat = true
	}
	return
	}

	func gomips() string {
	switch v := envOr("GOMIPS", defaultGOMIPS); v {
	case "hardfloat", "softfloat":
	return v
	}
	Error = fmt.Errorf("invalid GOMIPS: must be hardfloat, softfloat")
	return defaultGOMIPS
	}

	func gomips64() string {
	switch v := envOr("GOMIPS64", defaultGOMIPS64); v {
	case "hardfloat", "softfloat":
	return v
	}
	Error = fmt.Errorf("invalid GOMIPS64: must be hardfloat, softfloat")
	return defaultGOMIPS64
	}

	func goppc64() int {
	switch v := envOr("GOPPC64", defaultGOPPC64); v {
	case "power8":
	return 8
	case "power9":
	return 9
	case "power10":
	return 10
	}
	Error = fmt.Errorf("invalid GOPPC64: must be power8, power9, power10")
	return int(defaultGOPPC64[len("power")] - '0')
	}

	type gowasmFeatures struct {
	SatConv bool
	SignExt bool
	}

	func (f gowasmFeatures) String() string {
	var flags []string
	if f.SatConv {
	flags = append(flags, "satconv")
	}
	if f.SignExt {
	flags = append(flags, "signext")
	}
	return strings.Join(flags, ",")
	}

	func gowasm() (f gowasmFeatures) {
	for _, opt := range strings.Split(envOr("GOWASM", ""), ",") {
	switch opt {
	case "satconv":
	f.SatConv = true
	case "signext":
	f.SignExt = true
	case "":
	// ignore
	default:
	Error = fmt.Errorf("invalid GOWASM: no such feature %q", opt)
	}
	}
	return
	}

	func Getgoextlinkenabled() string {
	return envOr("GO_EXTLINK_ENABLED", defaultGO_EXTLINK_ENABLED)
	}

	func toolTags() []string {
	tags := experimentTags()
	tags = append(tags, gogoarchTags()...)
	return tags
	}

	func experimentTags() []string {
	var list []string
	// For each experiment that has been enabled in the toolchain, define a
	// build tag with the same name but prefixed by "goexperiment." which can be
	// used for compiling alternative files for the experiment. This allows
	// changes for the experiment, like extra struct fields in the runtime,
	// without affecting the base non-experiment code at all.
	for _, exp := range Experiment.Enabled() {
	list = append(list, "goexperiment."+exp)
	}
	return list
	}

	// GOGOARCH returns the name and value of the GO$GOARCH setting.
	// For example, if GOARCH is "amd64" it might return "GOAMD64", "v2".
	func GOGOARCH() (name, value string) {
	switch GOARCH {
	case "386":
	return "GO386", GO386
	case "amd64":
	return "GOAMD64", fmt.Sprintf("v%d", GOAMD64)
	case "arm":
	return "GOARM", GOARM.String()
	case "mips", "mipsle":
	return "GOMIPS", GOMIPS
	case "mips64", "mips64le":
	return "GOMIPS64", GOMIPS64
	case "ppc64", "ppc64le":
	return "GOPPC64", fmt.Sprintf("power%d", GOPPC64)
	case "wasm":
	return "GOWASM", GOWASM.String()
	}
	return "", ""
	}

	func gogoarchTags() []string {
	switch GOARCH {
	case "386":
	return []string{GOARCH + "." + GO386}
	case "amd64":
	var list []string
	for i := 1; i <= GOAMD64; i++ {
	list = append(list, fmt.Sprintf("%s.v%d", GOARCH, i))
	}
	return list
	case "arm":
	var list []string
	for i := 5; i <= GOARM.Version; i++ {
	list = append(list, fmt.Sprintf("%s.%d", GOARCH, i))
	}
	return list
	case "mips", "mipsle":
	return []string{GOARCH + "." + GOMIPS}
	case "mips64", "mips64le":
	return []string{GOARCH + "." + GOMIPS64}
	case "ppc64", "ppc64le":
	var list []string
	for i := 8; i <= GOPPC64; i++ {
	list = append(list, fmt.Sprintf("%s.power%d", GOARCH, i))
	}
	return list
	case "wasm":
	var list []string
	if GOWASM.SatConv {
	list = append(list, GOARCH+".satconv")
	}
	if GOWASM.SignExt {
	list = append(list, GOARCH+".signext")
	}
	return list
	}
	return nil
	}