src/cmd/internal/objabi/util.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 (
 	"fmt"
 	"log"
 	"os"
 	"strings"
 )

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

 var (
 	defaultGOROOT string // set by linker

 	GOROOT   = envOr("GOROOT", defaultGOROOT)
 	GOARCH   = envOr("GOARCH", defaultGOARCH)
 	GOOS     = envOr("GOOS", defaultGOOS)
 	GO386    = envOr("GO386", defaultGO386)
 	GOARM    = goarm()
 	GOMIPS   = gomips()
 	GOMIPS64 = gomips64()
 	GOPPC64  = goppc64()
 	GOWASM   = gowasm()
 	GO_LDSO  = defaultGO_LDSO
 	Version  = version

 	// GOEXPERIMENT is a comma-separated list of enabled
 	// experiments. This is derived from the GOEXPERIMENT
 	// environment variable if set, or the value of GOEXPERIMENT
 	// when make.bash was run if not.
 	GOEXPERIMENT string // Set by package init
 )

 const (
 	ElfRelocOffset   = 256
 	MachoRelocOffset = 2048 // reserve enough space for ELF relocations
 )

 func goarm() int {
 	def := defaultGOARM
 	if GOOS == "android" && GOARCH == "arm" {
 		// Android arm devices always support GOARM=7.
 		def = "7"
 	}
 	switch v := envOr("GOARM", def); v {
 	case "5":
 		return 5
 	case "6":
 		return 6
 	case "7":
 		return 7
 	}
 	// Fail here, rather than validate at multiple call sites.
 	log.Fatalf("Invalid GOARM value. Must be 5, 6, or 7.")
 	panic("unreachable")
 }

 func gomips() string {
 	switch v := envOr("GOMIPS", defaultGOMIPS); v {
 	case "hardfloat", "softfloat":
 		return v
 	}
 	log.Fatalf("Invalid GOMIPS value. Must be hardfloat or softfloat.")
 	panic("unreachable")
 }

 func gomips64() string {
 	switch v := envOr("GOMIPS64", defaultGOMIPS64); v {
 	case "hardfloat", "softfloat":
 		return v
 	}
 	log.Fatalf("Invalid GOMIPS64 value. Must be hardfloat or softfloat.")
 	panic("unreachable")
 }

 func goppc64() int {
 	switch v := envOr("GOPPC64", defaultGOPPC64); v {
 	case "power8":
 		return 8
 	case "power9":
 		return 9
 	}
 	log.Fatalf("Invalid GOPPC64 value. Must be power8 or power9.")
 	panic("unreachable")
 }

 type gowasmFeatures struct {
 	SignExt bool
 	SatConv 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:
 			log.Fatalf("Invalid GOWASM value. No such feature: " + opt)
 		}
 	}
 	return
 }

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

 func init() {
 	// Capture "default" experiments.
 	defaultExpstring = Expstring()

 	goexperiment := envOr("GOEXPERIMENT", defaultGOEXPERIMENT)

 	// GOEXPERIMENT=none overrides all experiments enabled at dist time.
 	if goexperiment != "none" {
 		for _, f := range strings.Split(goexperiment, ",") {
 			if f != "" {
 				addexp(f)
 			}
 		}
 	}

 	// regabi is only supported on amd64.
 	if GOARCH != "amd64" {
 		Experiment.regabi = false
 		Experiment.RegabiWrappers = false
 		Experiment.RegabiG = false
 		Experiment.RegabiReflect = false
 		Experiment.RegabiDefer = false
 		Experiment.RegabiArgs = false
 	}
 	// Setting regabi sets working sub-experiments.
 	if Experiment.regabi {
 		Experiment.RegabiWrappers = true
 		Experiment.RegabiG = true
 		Experiment.RegabiReflect = true
 		// Not ready yet:
 		//Experiment.RegabiDefer = true
 		//Experiment.RegabiArgs = true
 	}
 	// Check regabi dependencies.
 	if Experiment.RegabiG && !Experiment.RegabiWrappers {
 		panic("GOEXPERIMENT regabig requires regabiwrappers")
 	}
 	if Experiment.RegabiArgs && !(Experiment.RegabiWrappers && Experiment.RegabiReflect && Experiment.RegabiDefer) {
 		panic("GOEXPERIMENT regabiargs requires regabiwrappers,regabireflect,regabidefer")
 	}

 	// Set GOEXPERIMENT to the parsed and canonicalized set of experiments.
 	// This format must be parseable by runtime.haveexperiment.
 	GOEXPERIMENT = expList()
 }

 // FramePointerEnabled enables the use of platform conventions for
 // saving frame pointers.
 //
 // This used to be an experiment, but now it's always enabled on
 // platforms that support it.
 //
 // Note: must agree with runtime.framepointer_enabled.
 var FramePointerEnabled = GOARCH == "amd64" || GOARCH == "arm64"

 func addexp(s string) {
 	// We could do general integer parsing here, but there's no need yet.
 	v, vb := 1, true
 	name := s
 	if len(name) > 2 && name[:2] == "no" {
 		v, vb = 0, false
 		name = name[2:]
 	}
 	for i := 0; i < len(exper); i++ {
 		if exper[i].name == name {
 			switch val := exper[i].val.(type) {
 			case *int:
 				*val = v
 			case *bool:
 				*val = vb
 			default:
 				panic("bad GOEXPERIMENT type for " + s)
 			}
 			return
 		}
 	}

 	fmt.Printf("unknown experiment %s\n", s)
 	os.Exit(2)
 }

 // Experiment contains flags for GOEXPERIMENTs.
 var Experiment = ExpFlags{}

 type ExpFlags struct {
 	FieldTrack        bool
 	PreemptibleLoops  bool
 	StaticLockRanking bool

 	// regabi is split into several sub-experiments that can be
 	// enabled individually. GOEXPERIMENT=regabi implies the
 	// subset that are currently "working". Not all combinations work.
 	regabi bool
 	// RegabiWrappers enables ABI wrappers for calling between
 	// ABI0 and ABIInternal functions. Without this, the ABIs are
 	// assumed to be identical so cross-ABI calls are direct.
 	RegabiWrappers bool
 	// RegabiG enables dedicated G and zero registers in
 	// ABIInternal.
 	//
 	// Requires wrappers because it makes the ABIs incompatible.
 	RegabiG bool
 	// RegabiReflect enables the register-passing paths in
 	// reflection calls. This is also gated by intArgRegs in
 	// reflect and runtime (which are disabled by default) so it
 	// can be used in targeted tests.
 	RegabiReflect bool
 	// RegabiDefer enables desugaring defer and go calls
 	// into argument-less closures.
 	RegabiDefer bool
 	// RegabiArgs enables register arguments/results in all
 	// compiled Go functions.
 	//
 	// Requires wrappers, reflect, defer.
 	RegabiArgs bool
 }

 // Toolchain experiments.
 // These are controlled by the GOEXPERIMENT environment
 // variable recorded when the toolchain is built.
 var exper = []struct {
 	name string
 	val  interface{} // Must be *int or *bool
 }{
 	{"fieldtrack", &Experiment.FieldTrack},
 	{"preemptibleloops", &Experiment.PreemptibleLoops},
 	{"staticlockranking", &Experiment.StaticLockRanking},
 	{"regabi", &Experiment.regabi},
 	{"regabiwrappers", &Experiment.RegabiWrappers},
 	{"regabig", &Experiment.RegabiG},
 	{"regabireflect", &Experiment.RegabiReflect},
 	{"regabidefer", &Experiment.RegabiDefer},
 	{"regabiargs", &Experiment.RegabiArgs},
 }

 var defaultExpstring string

 // expList returns the list of enabled GOEXPERIMENTS as a
 // commas-separated list.
 func expList() string {
 	buf := ""
 	for i := range exper {
 		switch val := exper[i].val.(type) {
 		case *int:
 			if *val != 0 {
 				buf += "," + exper[i].name
 			}
 		case *bool:
 			if *val {
 				buf += "," + exper[i].name
 			}
 		}
 	}
 	if len(buf) == 0 {
 		return ""
 	}
 	return buf[1:]
 }

 // Expstring returns the GOEXPERIMENT string that should appear in Go
 // version signatures. This always starts with "X:".
 func Expstring() string {
 	list := expList()
 	if list == "" {
 		return "X:none"
 	}
 	return "X:" + list
 }
	// 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 (
	"fmt"
	"log"
	"os"
	"strings"
	)

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

	var (
	defaultGOROOT string // set by linker

	GOROOT = envOr("GOROOT", defaultGOROOT)
	GOARCH = envOr("GOARCH", defaultGOARCH)
	GOOS = envOr("GOOS", defaultGOOS)
	GO386 = envOr("GO386", defaultGO386)
	GOARM = goarm()
	GOMIPS = gomips()
	GOMIPS64 = gomips64()
	GOPPC64 = goppc64()
	GOWASM = gowasm()
	GO_LDSO = defaultGO_LDSO
	Version = version

	// GOEXPERIMENT is a comma-separated list of enabled
	// experiments. This is derived from the GOEXPERIMENT
	// environment variable if set, or the value of GOEXPERIMENT
	// when make.bash was run if not.
	GOEXPERIMENT string // Set by package init
	)

	const (
	ElfRelocOffset = 256
	MachoRelocOffset = 2048 // reserve enough space for ELF relocations
	)

	func goarm() int {
	def := defaultGOARM
	if GOOS == "android" && GOARCH == "arm" {
	// Android arm devices always support GOARM=7.
	def = "7"
	}
	switch v := envOr("GOARM", def); v {
	case "5":
	return 5
	case "6":
	return 6
	case "7":
	return 7
	}
	// Fail here, rather than validate at multiple call sites.
	log.Fatalf("Invalid GOARM value. Must be 5, 6, or 7.")
	panic("unreachable")
	}

	func gomips() string {
	switch v := envOr("GOMIPS", defaultGOMIPS); v {
	case "hardfloat", "softfloat":
	return v
	}
	log.Fatalf("Invalid GOMIPS value. Must be hardfloat or softfloat.")
	panic("unreachable")
	}

	func gomips64() string {
	switch v := envOr("GOMIPS64", defaultGOMIPS64); v {
	case "hardfloat", "softfloat":
	return v
	}
	log.Fatalf("Invalid GOMIPS64 value. Must be hardfloat or softfloat.")
	panic("unreachable")
	}

	func goppc64() int {
	switch v := envOr("GOPPC64", defaultGOPPC64); v {
	case "power8":
	return 8
	case "power9":
	return 9
	}
	log.Fatalf("Invalid GOPPC64 value. Must be power8 or power9.")
	panic("unreachable")
	}

	type gowasmFeatures struct {
	SignExt bool
	SatConv 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:
	log.Fatalf("Invalid GOWASM value. No such feature: " + opt)
	}
	}
	return
	}

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

	func init() {
	// Capture "default" experiments.
	defaultExpstring = Expstring()

	goexperiment := envOr("GOEXPERIMENT", defaultGOEXPERIMENT)

	// GOEXPERIMENT=none overrides all experiments enabled at dist time.
	if goexperiment != "none" {
	for _, f := range strings.Split(goexperiment, ",") {
	if f != "" {
	addexp(f)
	}
	}
	}

	// regabi is only supported on amd64.
	if GOARCH != "amd64" {
	Experiment.regabi = false
	Experiment.RegabiWrappers = false
	Experiment.RegabiG = false
	Experiment.RegabiReflect = false
	Experiment.RegabiDefer = false
	Experiment.RegabiArgs = false
	}
	// Setting regabi sets working sub-experiments.
	if Experiment.regabi {
	Experiment.RegabiWrappers = true
	Experiment.RegabiG = true
	Experiment.RegabiReflect = true
	// Not ready yet:
	//Experiment.RegabiDefer = true
	//Experiment.RegabiArgs = true
	}
	// Check regabi dependencies.
	if Experiment.RegabiG && !Experiment.RegabiWrappers {
	panic("GOEXPERIMENT regabig requires regabiwrappers")
	}
	if Experiment.RegabiArgs && !(Experiment.RegabiWrappers && Experiment.RegabiReflect && Experiment.RegabiDefer) {
	panic("GOEXPERIMENT regabiargs requires regabiwrappers,regabireflect,regabidefer")
	}

	// Set GOEXPERIMENT to the parsed and canonicalized set of experiments.
	// This format must be parseable by runtime.haveexperiment.
	GOEXPERIMENT = expList()
	}

	// FramePointerEnabled enables the use of platform conventions for
	// saving frame pointers.
	//
	// This used to be an experiment, but now it's always enabled on
	// platforms that support it.
	//
	// Note: must agree with runtime.framepointer_enabled.
	var FramePointerEnabled = GOARCH == "amd64" \|\| GOARCH == "arm64"

	func addexp(s string) {
	// We could do general integer parsing here, but there's no need yet.
	v, vb := 1, true
	name := s
	if len(name) > 2 && name[:2] == "no" {
	v, vb = 0, false
	name = name[2:]
	}
	for i := 0; i < len(exper); i++ {
	if exper[i].name == name {
	switch val := exper[i].val.(type) {
	case *int:
	*val = v
	case *bool:
	*val = vb
	default:
	panic("bad GOEXPERIMENT type for " + s)
	}
	return
	}
	}

	fmt.Printf("unknown experiment %s\n", s)
	os.Exit(2)
	}

	// Experiment contains flags for GOEXPERIMENTs.
	var Experiment = ExpFlags{}

	type ExpFlags struct {
	FieldTrack bool
	PreemptibleLoops bool
	StaticLockRanking bool

	// regabi is split into several sub-experiments that can be
	// enabled individually. GOEXPERIMENT=regabi implies the
	// subset that are currently "working". Not all combinations work.
	regabi bool
	// RegabiWrappers enables ABI wrappers for calling between
	// ABI0 and ABIInternal functions. Without this, the ABIs are
	// assumed to be identical so cross-ABI calls are direct.
	RegabiWrappers bool
	// RegabiG enables dedicated G and zero registers in
	// ABIInternal.
	//
	// Requires wrappers because it makes the ABIs incompatible.
	RegabiG bool
	// RegabiReflect enables the register-passing paths in
	// reflection calls. This is also gated by intArgRegs in
	// reflect and runtime (which are disabled by default) so it
	// can be used in targeted tests.
	RegabiReflect bool
	// RegabiDefer enables desugaring defer and go calls
	// into argument-less closures.
	RegabiDefer bool
	// RegabiArgs enables register arguments/results in all
	// compiled Go functions.
	//
	// Requires wrappers, reflect, defer.
	RegabiArgs bool
	}

	// Toolchain experiments.
	// These are controlled by the GOEXPERIMENT environment
	// variable recorded when the toolchain is built.
	var exper = []struct {
	name string
	val interface{} // Must be int or bool
	}{
	{"fieldtrack", &Experiment.FieldTrack},
	{"preemptibleloops", &Experiment.PreemptibleLoops},
	{"staticlockranking", &Experiment.StaticLockRanking},
	{"regabi", &Experiment.regabi},
	{"regabiwrappers", &Experiment.RegabiWrappers},
	{"regabig", &Experiment.RegabiG},
	{"regabireflect", &Experiment.RegabiReflect},
	{"regabidefer", &Experiment.RegabiDefer},
	{"regabiargs", &Experiment.RegabiArgs},
	}

	var defaultExpstring string

	// expList returns the list of enabled GOEXPERIMENTS as a
	// commas-separated list.
	func expList() string {
	buf := ""
	for i := range exper {
	switch val := exper[i].val.(type) {
	case *int:
	if *val != 0 {
	buf += "," + exper[i].name
	}
	case *bool:
	if *val {
	buf += "," + exper[i].name
	}
	}
	}
	if len(buf) == 0 {
	return ""
	}
	return buf[1:]
	}

	// Expstring returns the GOEXPERIMENT string that should appear in Go
	// version signatures. This always starts with "X:".
	func Expstring() string {
	list := expList()
	if list == "" {
	return "X:none"
	}
	return "X:" + list
	}