android/config.go - android_build_soong - Gitiles

 // Copyright 2015 Google Inc. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 package android

 import (
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
 	"strconv"
 	"strings"
 	"sync"

 	"github.com/google/blueprint/bootstrap"
 	"github.com/google/blueprint/proptools"
 )

 var Bool = proptools.Bool
 var String = proptools.String
 var FutureApiLevel = 10000

 // The configuration file name
 const configFileName = "soong.config"
 const productVariablesFileName = "soong.variables"

 // A FileConfigurableOptions contains options which can be configured by the
 // config file. These will be included in the config struct.
 type FileConfigurableOptions struct {
 	Mega_device *bool `json:",omitempty"`
 	Ndk_abis    *bool `json:",omitempty"`
 	Host_bionic *bool `json:",omitempty"`
 }

 func (f *FileConfigurableOptions) SetDefaultConfig() {
 	*f = FileConfigurableOptions{}
 }

 // A Config object represents the entire build configuration for Android.
 type Config struct {
 	*config
 }

 func (c Config) BuildDir() string {
 	return c.buildDir
 }

 // A DeviceConfig object represents the configuration for a particular device being built.  For
 // now there will only be one of these, but in the future there may be multiple devices being
 // built
 type DeviceConfig struct {
 	*deviceConfig
 }

 type config struct {
 	FileConfigurableOptions
 	ProductVariables productVariables

 	PrimaryBuilder           string
 	ConfigFileName           string
 	ProductVariablesFileName string

 	Targets        map[OsClass][]Target
 	BuildOsVariant string

 	deviceConfig *deviceConfig

 	srcDir   string // the path of the root source directory
 	buildDir string // the path of the build output directory

 	env       map[string]string
 	envLock   sync.Mutex
 	envDeps   map[string]string
 	envFrozen bool

 	inMake bool

 	captureBuild      bool // true for tests, saves build parameters for each module
 	ignoreEnvironment bool // true for tests, returns empty from all Getenv calls

 	useOpenJDK9    bool // Use OpenJDK9, but possibly target 1.8
 	targetOpenJDK9 bool // Use OpenJDK9 and target 1.9

 	stopBefore bootstrap.StopBefore

 	OncePer
 }

 type deviceConfig struct {
 	config *config
 	OncePer
 }

 type jsonConfigurable interface {
 	SetDefaultConfig()
 }

 func loadConfig(config *config) error {
 	err := loadFromConfigFile(&config.FileConfigurableOptions, config.ConfigFileName)
 	if err != nil {
 		return err
 	}

 	return loadFromConfigFile(&config.ProductVariables, config.ProductVariablesFileName)
 }

 // loads configuration options from a JSON file in the cwd.
 func loadFromConfigFile(configurable jsonConfigurable, filename string) error {
 	// Try to open the file
 	configFileReader, err := os.Open(filename)
 	defer configFileReader.Close()
 	if os.IsNotExist(err) {
 		// Need to create a file, so that blueprint & ninja don't get in
 		// a dependency tracking loop.
 		// Make a file-configurable-options with defaults, write it out using
 		// a json writer.
 		configurable.SetDefaultConfig()
 		err = saveToConfigFile(configurable, filename)
 		if err != nil {
 			return err
 		}
 	} else if err != nil {
 		return fmt.Errorf("config file: could not open %s: %s", filename, err.Error())
 	} else {
 		// Make a decoder for it
 		jsonDecoder := json.NewDecoder(configFileReader)
 		err = jsonDecoder.Decode(configurable)
 		if err != nil {
 			return fmt.Errorf("config file: %s did not parse correctly: %s", filename, err.Error())
 		}
 	}

 	// No error
 	return nil
 }

 // atomically writes the config file in case two copies of soong_build are running simultaneously
 // (for example, docs generation and ninja manifest generation)
 func saveToConfigFile(config jsonConfigurable, filename string) error {
 	data, err := json.MarshalIndent(&config, "", "    ")
 	if err != nil {
 		return fmt.Errorf("cannot marshal config data: %s", err.Error())
 	}

 	f, err := ioutil.TempFile(filepath.Dir(filename), "config")
 	if err != nil {
 		return fmt.Errorf("cannot create empty config file %s: %s\n", filename, err.Error())
 	}
 	defer os.Remove(f.Name())
 	defer f.Close()

 	_, err = f.Write(data)
 	if err != nil {
 		return fmt.Errorf("default config file: %s could not be written: %s", filename, err.Error())
 	}

 	_, err = f.WriteString("\n")
 	if err != nil {
 		return fmt.Errorf("default config file: %s could not be written: %s", filename, err.Error())
 	}

 	f.Close()
 	os.Rename(f.Name(), filename)

 	return nil
 }

 // TestConfig returns a Config object suitable for using for tests
 func TestConfig(buildDir string, env map[string]string) Config {
 	config := &config{
 		ProductVariables: productVariables{
 			DeviceName:           stringPtr("test_device"),
 			Platform_sdk_version: intPtr(26),
 			AAPTConfig:           &[]string{"normal", "large", "xlarge", "hdpi", "xhdpi", "xxhdpi"},
 			AAPTPreferredConfig:  stringPtr("xhdpi"),
 			AAPTCharacteristics:  stringPtr("nosdcard"),
 			AAPTPrebuiltDPI:      &[]string{"xhdpi", "xxhdpi"},
 		},

 		buildDir:     buildDir,
 		captureBuild: true,
 		env:          env,
 	}
 	config.deviceConfig = &deviceConfig{
 		config: config,
 	}

 	if err := config.fromEnv(); err != nil {
 		panic(err)
 	}

 	return Config{config}
 }

 // TestConfig returns a Config object suitable for using for tests that need to run the arch mutator
 func TestArchConfig(buildDir string, env map[string]string) Config {
 	testConfig := TestConfig(buildDir, env)
 	config := testConfig.config

 	config.Targets = map[OsClass][]Target{
 		Device: []Target{
 			{Android, Arch{ArchType: Arm64, ArchVariant: "armv8-a", Native: true}},
 			{Android, Arch{ArchType: Arm, ArchVariant: "armv7-a-neon", Native: true}},
 		},
 		Host: []Target{
 			{BuildOs, Arch{ArchType: X86_64}},
 			{BuildOs, Arch{ArchType: X86}},
 		},
 	}

 	return testConfig
 }

 // New creates a new Config object.  The srcDir argument specifies the path to
 // the root source directory. It also loads the config file, if found.
 func NewConfig(srcDir, buildDir string) (Config, error) {
 	// Make a config with default options
 	config := &config{
 		ConfigFileName:           filepath.Join(buildDir, configFileName),
 		ProductVariablesFileName: filepath.Join(buildDir, productVariablesFileName),

 		env: originalEnv,

 		srcDir:   srcDir,
 		buildDir: buildDir,
 	}

 	config.deviceConfig = &deviceConfig{
 		config: config,
 	}

 	// Sanity check the build and source directories. This won't catch strange
 	// configurations with symlinks, but at least checks the obvious cases.
 	absBuildDir, err := filepath.Abs(buildDir)
 	if err != nil {
 		return Config{}, err
 	}

 	absSrcDir, err := filepath.Abs(srcDir)
 	if err != nil {
 		return Config{}, err
 	}

 	if strings.HasPrefix(absSrcDir, absBuildDir) {
 		return Config{}, fmt.Errorf("Build dir must not contain source directory")
 	}

 	// Load any configurable options from the configuration file
 	err = loadConfig(config)
 	if err != nil {
 		return Config{}, err
 	}

 	inMakeFile := filepath.Join(buildDir, ".soong.in_make")
 	if _, err := os.Stat(inMakeFile); err == nil {
 		config.inMake = true
 	}

 	targets, err := decodeTargetProductVariables(config)
 	if err != nil {
 		return Config{}, err
 	}

 	var archConfig []archConfig
 	if Bool(config.Mega_device) {
 		archConfig = getMegaDeviceConfig()
 	} else if Bool(config.Ndk_abis) {
 		archConfig = getNdkAbisConfig()
 	}

 	if archConfig != nil {
 		deviceTargets, err := decodeArchSettings(archConfig)
 		if err != nil {
 			return Config{}, err
 		}
 		targets[Device] = deviceTargets
 	}

 	config.Targets = targets
 	config.BuildOsVariant = targets[Host][0].String()

 	if err := config.fromEnv(); err != nil {
 		return Config{}, err
 	}

 	return Config{config}, nil
 }

 func (c *config) fromEnv() error {
 	switch c.Getenv("EXPERIMENTAL_USE_OPENJDK9") {
 	case "":
 		if c.Getenv("RUN_ERROR_PRONE") != "true" {
 			// Use OpenJDK9, but target 1.8
 			c.useOpenJDK9 = true
 		}
 	case "false":
 		// Use OpenJDK8
 	case "1.8":
 		// Use OpenJDK9, but target 1.8
 		c.useOpenJDK9 = true
 	case "true":
 		// Use OpenJDK9 and target 1.9
 		c.useOpenJDK9 = true
 		c.targetOpenJDK9 = true
 	default:
 		return fmt.Errorf(`Invalid value for EXPERIMENTAL_USE_OPENJDK9, should be "", "false", "1.8", or "true"`)
 	}

 	return nil
 }

 func (c *config) StopBefore() bootstrap.StopBefore {
 	return c.stopBefore
 }

 func (c *config) SetStopBefore(stopBefore bootstrap.StopBefore) {
 	c.stopBefore = stopBefore
 }

 var _ bootstrap.ConfigStopBefore = (*config)(nil)

 func (c *config) BlueprintToolLocation() string {
 	return filepath.Join(c.buildDir, "host", c.PrebuiltOS(), "bin")
 }

 var _ bootstrap.ConfigBlueprintToolLocation = (*config)(nil)

 // HostSystemTool looks for non-hermetic tools from the system we're running on.
 // Generally shouldn't be used, but useful to find the XCode SDK, etc.
 func (c *config) HostSystemTool(name string) string {
 	for _, dir := range filepath.SplitList(c.Getenv("PATH")) {
 		path := filepath.Join(dir, name)
 		if s, err := os.Stat(path); err != nil {
 			continue
 		} else if m := s.Mode(); !s.IsDir() && m&0111 != 0 {
 			return path
 		}
 	}
 	return name
 }

 // PrebuiltOS returns the name of the host OS used in prebuilts directories
 func (c *config) PrebuiltOS() string {
 	switch runtime.GOOS {
 	case "linux":
 		return "linux-x86"
 	case "darwin":
 		return "darwin-x86"
 	default:
 		panic("Unknown GOOS")
 	}
 }

 // GoRoot returns the path to the root directory of the Go toolchain.
 func (c *config) GoRoot() string {
 	return fmt.Sprintf("%s/prebuilts/go/%s", c.srcDir, c.PrebuiltOS())
 }

 func (c *config) CpPreserveSymlinksFlags() string {
 	switch runtime.GOOS {
 	case "darwin":
 		return "-R"
 	case "linux":
 		return "-d"
 	default:
 		return ""
 	}
 }

 func (c *config) Getenv(key string) string {
 	var val string
 	var exists bool
 	c.envLock.Lock()
 	defer c.envLock.Unlock()
 	if c.envDeps == nil {
 		c.envDeps = make(map[string]string)
 	}
 	if val, exists = c.envDeps[key]; !exists {
 		if c.envFrozen {
 			panic("Cannot access new environment variables after envdeps are frozen")
 		}
 		val, _ = c.env[key]
 		c.envDeps[key] = val
 	}
 	return val
 }

 func (c *config) GetenvWithDefault(key string, defaultValue string) string {
 	ret := c.Getenv(key)
 	if ret == "" {
 		return defaultValue
 	}
 	return ret
 }

 func (c *config) IsEnvTrue(key string) bool {
 	value := c.Getenv(key)
 	return value == "1" || value == "y" || value == "yes" || value == "on" || value == "true"
 }

 func (c *config) IsEnvFalse(key string) bool {
 	value := c.Getenv(key)
 	return value == "0" || value == "n" || value == "no" || value == "off" || value == "false"
 }

 func (c *config) EnvDeps() map[string]string {
 	c.envLock.Lock()
 	defer c.envLock.Unlock()
 	c.envFrozen = true
 	return c.envDeps
 }

 func (c *config) EmbeddedInMake() bool {
 	return c.inMake
 }

 func (c *config) BuildId() string {
 	return String(c.ProductVariables.BuildId)
 }

 func (c *config) BuildNumberFromFile() string {
 	return String(c.ProductVariables.BuildNumberFromFile)
 }

 // DeviceName returns the name of the current device target
 // TODO: take an AndroidModuleContext to select the device name for multi-device builds
 func (c *config) DeviceName() string {
 	return *c.ProductVariables.DeviceName
 }

 func (c *config) ResourceOverlays() []string {
 	if c.ProductVariables.ResourceOverlays == nil {
 		return nil
 	}
 	return *c.ProductVariables.ResourceOverlays
 }

 func (c *config) PlatformSdkVersionInt() int {
 	return *c.ProductVariables.Platform_sdk_version
 }

 func (c *config) PlatformSdkVersion() string {
 	return strconv.Itoa(c.PlatformSdkVersionInt())
 }

 func (c *config) MinSupportedSdkVersion() int {
 	return 14
 }

 func (c *config) DefaultAppTargetSdkInt() int {
 	if Bool(c.ProductVariables.Platform_sdk_final) {
 		return c.PlatformSdkVersionInt()
 	} else {
 		return FutureApiLevel
 	}
 }

 func (c *config) AppsDefaultVersionName() string {
 	return String(c.ProductVariables.AppsDefaultVersionName)
 }

 // Codenames that are active in the current lunch target.
 func (c *config) PlatformVersionActiveCodenames() []string {
 	return c.ProductVariables.Platform_version_active_codenames
 }

 // Codenames that are available in the branch but not included in the current
 // lunch target.
 func (c *config) PlatformVersionFutureCodenames() []string {
 	return c.ProductVariables.Platform_version_future_codenames
 }

 // All possible codenames in the current branch. NB: Not named AllCodenames
 // because "all" has historically meant "active" in make, and still does in
 // build.prop.
 func (c *config) PlatformVersionCombinedCodenames() []string {
 	combined := []string{}
 	combined = append(combined, c.PlatformVersionActiveCodenames()...)
 	combined = append(combined, c.PlatformVersionFutureCodenames()...)
 	return combined
 }

 func (c *config) ProductAAPTConfig() []string {
 	return stringSlice(c.ProductVariables.AAPTConfig)
 }

 func (c *config) ProductAAPTPreferredConfig() string {
 	return String(c.ProductVariables.AAPTPreferredConfig)
 }

 func (c *config) ProductAAPTCharacteristics() string {
 	return String(c.ProductVariables.AAPTCharacteristics)
 }

 func (c *config) ProductAAPTPrebuiltDPI() []string {
 	return stringSlice(c.ProductVariables.AAPTPrebuiltDPI)
 }

 func (c *config) DefaultAppCertificateDir(ctx PathContext) SourcePath {
 	defaultCert := String(c.ProductVariables.DefaultAppCertificate)
 	if defaultCert != "" {
 		return PathForSource(ctx, filepath.Dir(defaultCert))
 	} else {
 		return PathForSource(ctx, "build/target/product/security")
 	}
 }

 func (c *config) DefaultAppCertificate(ctx PathContext) (pem, key SourcePath) {
 	defaultCert := String(c.ProductVariables.DefaultAppCertificate)
 	if defaultCert != "" {
 		return PathForSource(ctx, defaultCert+".x509.pem"), PathForSource(ctx, defaultCert+".pk8")
 	} else {
 		defaultDir := c.DefaultAppCertificateDir(ctx)
 		return defaultDir.Join(ctx, "testkey.x509.pem"), defaultDir.Join(ctx, "testkey.pk8")
 	}
 }

 func (c *config) AllowMissingDependencies() bool {
 	return Bool(c.ProductVariables.Allow_missing_dependencies)
 }

 func (c *config) UnbundledBuild() bool {
 	return Bool(c.ProductVariables.Unbundled_build)
 }

 func (c *config) IsPdkBuild() bool {
 	return Bool(c.ProductVariables.Pdk)
 }

 func (c *config) MinimizeJavaDebugInfo() bool {
 	return Bool(c.ProductVariables.MinimizeJavaDebugInfo) && !Bool(c.ProductVariables.Eng)
 }

 func (c *config) DevicePrefer32BitExecutables() bool {
 	return Bool(c.ProductVariables.DevicePrefer32BitExecutables)
 }

 func (c *config) SkipDeviceInstall() bool {
 	return c.EmbeddedInMake()
 }

 func (c *config) SkipMegaDeviceInstall(path string) bool {
 	return Bool(c.Mega_device) &&
 		strings.HasPrefix(path, filepath.Join(c.buildDir, "target", "product"))
 }

 func (c *config) SanitizeHost() []string {
 	return append([]string(nil), c.ProductVariables.SanitizeHost...)
 }

 func (c *config) SanitizeDevice() []string {
 	return append([]string(nil), c.ProductVariables.SanitizeDevice...)
 }

 func (c *config) SanitizeDeviceDiag() []string {
 	return append([]string(nil), c.ProductVariables.SanitizeDeviceDiag...)
 }

 func (c *config) SanitizeDeviceArch() []string {
 	return append([]string(nil), c.ProductVariables.SanitizeDeviceArch...)
 }

 func (c *config) EnableCFI() bool {
 	if c.ProductVariables.EnableCFI == nil {
 		return true
 	} else {
 		return *c.ProductVariables.EnableCFI
 	}
 }

 func (c *config) Android64() bool {
 	for _, t := range c.Targets[Device] {
 		if t.Arch.ArchType.Multilib == "lib64" {
 			return true
 		}
 	}

 	return false
 }

 func (c *config) UseD8Desugar() bool {
 	return !c.IsEnvFalse("USE_D8_DESUGAR")
 }

 func (c *config) UseGoma() bool {
 	return Bool(c.ProductVariables.UseGoma)
 }

 // Returns true if OpenJDK9 prebuilts are being used
 func (c *config) UseOpenJDK9() bool {
 	return c.useOpenJDK9
 }

 // Returns true if -source 1.9 -target 1.9 is being passed to javac
 func (c *config) TargetOpenJDK9() bool {
 	return c.targetOpenJDK9
 }

 func (c *config) ClangTidy() bool {
 	return Bool(c.ProductVariables.ClangTidy)
 }

 func (c *config) TidyChecks() string {
 	if c.ProductVariables.TidyChecks == nil {
 		return ""
 	}
 	return *c.ProductVariables.TidyChecks
 }

 func (c *config) LibartImgHostBaseAddress() string {
 	return "0x60000000"
 }

 func (c *config) LibartImgDeviceBaseAddress() string {
 	archType := Common
 	if len(c.Targets[Device]) > 0 {
 		archType = c.Targets[Device][0].Arch.ArchType
 	}
 	switch archType {
 	default:
 		return "0x70000000"
 	case Mips, Mips64:
 		return "0x5C000000"
 	}
 }

 func (c *config) ArtUseReadBarrier() bool {
 	return Bool(c.ProductVariables.ArtUseReadBarrier)
 }

 func (c *deviceConfig) Arches() []Arch {
 	var arches []Arch
 	for _, target := range c.config.Targets[Device] {
 		arches = append(arches, target.Arch)
 	}
 	return arches
 }

 func (c *deviceConfig) VendorPath() string {
 	if c.config.ProductVariables.VendorPath != nil {
 		return *c.config.ProductVariables.VendorPath
 	}
 	return "vendor"
 }

 func (c *deviceConfig) VndkVersion() string {
 	return String(c.config.ProductVariables.DeviceVndkVersion)
 }

 func (c *deviceConfig) PlatformVndkVersion() string {
 	return String(c.config.ProductVariables.Platform_vndk_version)
 }

 func (c *deviceConfig) ExtraVndkVersions() []string {
 	return c.config.ProductVariables.ExtraVndkVersions
 }

 func (c *deviceConfig) SystemSdkVersions() []string {
 	if c.config.ProductVariables.DeviceSystemSdkVersions == nil {
 		return nil
 	}
 	return *c.config.ProductVariables.DeviceSystemSdkVersions
 }

 func (c *deviceConfig) PlatformSystemSdkVersions() []string {
 	return c.config.ProductVariables.Platform_systemsdk_versions
 }

 func (c *deviceConfig) OdmPath() string {
 	if c.config.ProductVariables.OdmPath != nil {
 		return *c.config.ProductVariables.OdmPath
 	}
 	return "odm"
 }

 func (c *deviceConfig) ProductPath() string {
 	if c.config.ProductVariables.ProductPath != nil {
 		return *c.config.ProductVariables.ProductPath
 	}
 	return "product"
 }

 func (c *deviceConfig) BtConfigIncludeDir() string {
 	return String(c.config.ProductVariables.BtConfigIncludeDir)
 }

 func (c *deviceConfig) DeviceKernelHeaderDirs() []string {
 	return c.config.ProductVariables.DeviceKernelHeaders
 }

 func (c *deviceConfig) NativeCoverageEnabled() bool {
 	return Bool(c.config.ProductVariables.NativeCoverage)
 }

 func (c *deviceConfig) CoverageEnabledForPath(path string) bool {
 	coverage := false
 	if c.config.ProductVariables.CoveragePaths != nil {
 		if PrefixInList(path, *c.config.ProductVariables.CoveragePaths) {
 			coverage = true
 		}
 	}
 	if coverage && c.config.ProductVariables.CoverageExcludePaths != nil {
 		if PrefixInList(path, *c.config.ProductVariables.CoverageExcludePaths) {
 			coverage = false
 		}
 	}
 	return coverage
 }

 func (c *deviceConfig) PgoAdditionalProfileDirs() []string {
 	return c.config.ProductVariables.PgoAdditionalProfileDirs
 }

 func (c *config) IntegerOverflowDisabledForPath(path string) bool {
 	if c.ProductVariables.IntegerOverflowExcludePaths == nil {
 		return false
 	}
 	return PrefixInList(path, *c.ProductVariables.IntegerOverflowExcludePaths)
 }

 func (c *config) CFIDisabledForPath(path string) bool {
 	if c.ProductVariables.CFIExcludePaths == nil {
 		return false
 	}
 	return PrefixInList(path, *c.ProductVariables.CFIExcludePaths)
 }

 func (c *config) CFIEnabledForPath(path string) bool {
 	if c.ProductVariables.CFIIncludePaths == nil {
 		return false
 	}
 	return PrefixInList(path, *c.ProductVariables.CFIIncludePaths)
 }

 func stringSlice(s *[]string) []string {
 	if s != nil {
 		return *s
 	} else {
 		return nil
 	}
 }
	// Copyright 2015 Google Inc. All rights reserved.
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	package android

	import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"
	"runtime"
	"strconv"
	"strings"
	"sync"

	"github.com/google/blueprint/bootstrap"
	"github.com/google/blueprint/proptools"
	)

	var Bool = proptools.Bool
	var String = proptools.String
	var FutureApiLevel = 10000

	// The configuration file name
	const configFileName = "soong.config"
	const productVariablesFileName = "soong.variables"

	// A FileConfigurableOptions contains options which can be configured by the
	// config file. These will be included in the config struct.
	type FileConfigurableOptions struct {
	Mega_device *bool `json:",omitempty"`
	Ndk_abis *bool `json:",omitempty"`
	Host_bionic *bool `json:",omitempty"`
	}

	func (f *FileConfigurableOptions) SetDefaultConfig() {
	*f = FileConfigurableOptions{}
	}

	// A Config object represents the entire build configuration for Android.
	type Config struct {
	*config
	}

	func (c Config) BuildDir() string {
	return c.buildDir
	}

	// A DeviceConfig object represents the configuration for a particular device being built. For
	// now there will only be one of these, but in the future there may be multiple devices being
	// built
	type DeviceConfig struct {
	*deviceConfig
	}

	type config struct {
	FileConfigurableOptions
	ProductVariables productVariables

	PrimaryBuilder string
	ConfigFileName string
	ProductVariablesFileName string

	Targets map[OsClass][]Target
	BuildOsVariant string

	deviceConfig *deviceConfig

	srcDir string // the path of the root source directory
	buildDir string // the path of the build output directory

	env map[string]string
	envLock sync.Mutex
	envDeps map[string]string
	envFrozen bool

	inMake bool

	captureBuild bool // true for tests, saves build parameters for each module
	ignoreEnvironment bool // true for tests, returns empty from all Getenv calls

	useOpenJDK9 bool // Use OpenJDK9, but possibly target 1.8
	targetOpenJDK9 bool // Use OpenJDK9 and target 1.9

	stopBefore bootstrap.StopBefore

	OncePer
	}

	type deviceConfig struct {
	config *config
	OncePer
	}

	type jsonConfigurable interface {
	SetDefaultConfig()
	}

	func loadConfig(config *config) error {
	err := loadFromConfigFile(&config.FileConfigurableOptions, config.ConfigFileName)
	if err != nil {
	return err
	}

	return loadFromConfigFile(&config.ProductVariables, config.ProductVariablesFileName)
	}

	// loads configuration options from a JSON file in the cwd.
	func loadFromConfigFile(configurable jsonConfigurable, filename string) error {
	// Try to open the file
	configFileReader, err := os.Open(filename)
	defer configFileReader.Close()
	if os.IsNotExist(err) {
	// Need to create a file, so that blueprint & ninja don't get in
	// a dependency tracking loop.
	// Make a file-configurable-options with defaults, write it out using
	// a json writer.
	configurable.SetDefaultConfig()
	err = saveToConfigFile(configurable, filename)
	if err != nil {
	return err
	}
	} else if err != nil {
	return fmt.Errorf("config file: could not open %s: %s", filename, err.Error())
	} else {
	// Make a decoder for it
	jsonDecoder := json.NewDecoder(configFileReader)
	err = jsonDecoder.Decode(configurable)
	if err != nil {
	return fmt.Errorf("config file: %s did not parse correctly: %s", filename, err.Error())
	}
	}

	// No error
	return nil
	}

	// atomically writes the config file in case two copies of soong_build are running simultaneously
	// (for example, docs generation and ninja manifest generation)
	func saveToConfigFile(config jsonConfigurable, filename string) error {
	data, err := json.MarshalIndent(&config, "", " ")
	if err != nil {
	return fmt.Errorf("cannot marshal config data: %s", err.Error())
	}

	f, err := ioutil.TempFile(filepath.Dir(filename), "config")
	if err != nil {
	return fmt.Errorf("cannot create empty config file %s: %s\n", filename, err.Error())
	}
	defer os.Remove(f.Name())
	defer f.Close()

	_, err = f.Write(data)
	if err != nil {
	return fmt.Errorf("default config file: %s could not be written: %s", filename, err.Error())
	}

	_, err = f.WriteString("\n")
	if err != nil {
	return fmt.Errorf("default config file: %s could not be written: %s", filename, err.Error())
	}

	f.Close()
	os.Rename(f.Name(), filename)

	return nil
	}

	// TestConfig returns a Config object suitable for using for tests
	func TestConfig(buildDir string, env map[string]string) Config {
	config := &config{
	ProductVariables: productVariables{
	DeviceName: stringPtr("test_device"),
	Platform_sdk_version: intPtr(26),
	AAPTConfig: &[]string{"normal", "large", "xlarge", "hdpi", "xhdpi", "xxhdpi"},
	AAPTPreferredConfig: stringPtr("xhdpi"),
	AAPTCharacteristics: stringPtr("nosdcard"),
	AAPTPrebuiltDPI: &[]string{"xhdpi", "xxhdpi"},
	},

	buildDir: buildDir,
	captureBuild: true,
	env: env,
	}
	config.deviceConfig = &deviceConfig{
	config: config,
	}

	if err := config.fromEnv(); err != nil {
	panic(err)
	}

	return Config{config}
	}

	// TestConfig returns a Config object suitable for using for tests that need to run the arch mutator
	func TestArchConfig(buildDir string, env map[string]string) Config {
	testConfig := TestConfig(buildDir, env)
	config := testConfig.config

	config.Targets = map[OsClass][]Target{
	Device: []Target{
	{Android, Arch{ArchType: Arm64, ArchVariant: "armv8-a", Native: true}},
	{Android, Arch{ArchType: Arm, ArchVariant: "armv7-a-neon", Native: true}},
	},
	Host: []Target{
	{BuildOs, Arch{ArchType: X86_64}},
	{BuildOs, Arch{ArchType: X86}},
	},
	}

	return testConfig
	}

	// New creates a new Config object. The srcDir argument specifies the path to
	// the root source directory. It also loads the config file, if found.
	func NewConfig(srcDir, buildDir string) (Config, error) {
	// Make a config with default options
	config := &config{
	ConfigFileName: filepath.Join(buildDir, configFileName),
	ProductVariablesFileName: filepath.Join(buildDir, productVariablesFileName),

	env: originalEnv,

	srcDir: srcDir,
	buildDir: buildDir,
	}

	config.deviceConfig = &deviceConfig{
	config: config,
	}

	// Sanity check the build and source directories. This won't catch strange
	// configurations with symlinks, but at least checks the obvious cases.
	absBuildDir, err := filepath.Abs(buildDir)
	if err != nil {
	return Config{}, err
	}

	absSrcDir, err := filepath.Abs(srcDir)
	if err != nil {
	return Config{}, err
	}

	if strings.HasPrefix(absSrcDir, absBuildDir) {
	return Config{}, fmt.Errorf("Build dir must not contain source directory")
	}

	// Load any configurable options from the configuration file
	err = loadConfig(config)
	if err != nil {
	return Config{}, err
	}

	inMakeFile := filepath.Join(buildDir, ".soong.in_make")
	if _, err := os.Stat(inMakeFile); err == nil {
	config.inMake = true
	}

	targets, err := decodeTargetProductVariables(config)
	if err != nil {
	return Config{}, err
	}

	var archConfig []archConfig
	if Bool(config.Mega_device) {
	archConfig = getMegaDeviceConfig()
	} else if Bool(config.Ndk_abis) {
	archConfig = getNdkAbisConfig()
	}

	if archConfig != nil {
	deviceTargets, err := decodeArchSettings(archConfig)
	if err != nil {
	return Config{}, err
	}
	targets[Device] = deviceTargets
	}

	config.Targets = targets
	config.BuildOsVariant = targets[Host][0].String()

	if err := config.fromEnv(); err != nil {
	return Config{}, err
	}

	return Config{config}, nil
	}

	func (c *config) fromEnv() error {
	switch c.Getenv("EXPERIMENTAL_USE_OPENJDK9") {
	case "":
	if c.Getenv("RUN_ERROR_PRONE") != "true" {
	// Use OpenJDK9, but target 1.8
	c.useOpenJDK9 = true
	}
	case "false":
	// Use OpenJDK8
	case "1.8":
	// Use OpenJDK9, but target 1.8
	c.useOpenJDK9 = true
	case "true":
	// Use OpenJDK9 and target 1.9
	c.useOpenJDK9 = true
	c.targetOpenJDK9 = true
	default:
	return fmt.Errorf(`Invalid value for EXPERIMENTAL_USE_OPENJDK9, should be "", "false", "1.8", or "true"`)
	}

	return nil
	}

	func (c *config) StopBefore() bootstrap.StopBefore {
	return c.stopBefore
	}

	func (c *config) SetStopBefore(stopBefore bootstrap.StopBefore) {
	c.stopBefore = stopBefore
	}

	var _ bootstrap.ConfigStopBefore = (*config)(nil)

	func (c *config) BlueprintToolLocation() string {
	return filepath.Join(c.buildDir, "host", c.PrebuiltOS(), "bin")
	}

	var _ bootstrap.ConfigBlueprintToolLocation = (*config)(nil)

	// HostSystemTool looks for non-hermetic tools from the system we're running on.
	// Generally shouldn't be used, but useful to find the XCode SDK, etc.
	func (c *config) HostSystemTool(name string) string {
	for _, dir := range filepath.SplitList(c.Getenv("PATH")) {
	path := filepath.Join(dir, name)
	if s, err := os.Stat(path); err != nil {
	continue
	} else if m := s.Mode(); !s.IsDir() && m&0111 != 0 {
	return path
	}
	}
	return name
	}

	// PrebuiltOS returns the name of the host OS used in prebuilts directories
	func (c *config) PrebuiltOS() string {
	switch runtime.GOOS {
	case "linux":
	return "linux-x86"
	case "darwin":
	return "darwin-x86"
	default:
	panic("Unknown GOOS")
	}
	}

	// GoRoot returns the path to the root directory of the Go toolchain.
	func (c *config) GoRoot() string {
	return fmt.Sprintf("%s/prebuilts/go/%s", c.srcDir, c.PrebuiltOS())
	}

	func (c *config) CpPreserveSymlinksFlags() string {
	switch runtime.GOOS {
	case "darwin":
	return "-R"
	case "linux":
	return "-d"
	default:
	return ""
	}
	}

	func (c *config) Getenv(key string) string {
	var val string
	var exists bool
	c.envLock.Lock()
	defer c.envLock.Unlock()
	if c.envDeps == nil {
	c.envDeps = make(map[string]string)
	}
	if val, exists = c.envDeps[key]; !exists {
	if c.envFrozen {
	panic("Cannot access new environment variables after envdeps are frozen")
	}
	val, _ = c.env[key]
	c.envDeps[key] = val
	}
	return val
	}

	func (c *config) GetenvWithDefault(key string, defaultValue string) string {
	ret := c.Getenv(key)
	if ret == "" {
	return defaultValue
	}
	return ret
	}

	func (c *config) IsEnvTrue(key string) bool {
	value := c.Getenv(key)
	return value == "1" \|\| value == "y" \|\| value == "yes" \|\| value == "on" \|\| value == "true"
	}

	func (c *config) IsEnvFalse(key string) bool {
	value := c.Getenv(key)
	return value == "0" \|\| value == "n" \|\| value == "no" \|\| value == "off" \|\| value == "false"
	}

	func (c *config) EnvDeps() map[string]string {
	c.envLock.Lock()
	defer c.envLock.Unlock()
	c.envFrozen = true
	return c.envDeps
	}

	func (c *config) EmbeddedInMake() bool {
	return c.inMake
	}

	func (c *config) BuildId() string {
	return String(c.ProductVariables.BuildId)
	}

	func (c *config) BuildNumberFromFile() string {
	return String(c.ProductVariables.BuildNumberFromFile)
	}

	// DeviceName returns the name of the current device target
	// TODO: take an AndroidModuleContext to select the device name for multi-device builds
	func (c *config) DeviceName() string {
	return *c.ProductVariables.DeviceName
	}

	func (c *config) ResourceOverlays() []string {
	if c.ProductVariables.ResourceOverlays == nil {
	return nil
	}
	return *c.ProductVariables.ResourceOverlays
	}

	func (c *config) PlatformSdkVersionInt() int {
	return *c.ProductVariables.Platform_sdk_version
	}

	func (c *config) PlatformSdkVersion() string {
	return strconv.Itoa(c.PlatformSdkVersionInt())
	}

	func (c *config) MinSupportedSdkVersion() int {
	return 14
	}

	func (c *config) DefaultAppTargetSdkInt() int {
	if Bool(c.ProductVariables.Platform_sdk_final) {
	return c.PlatformSdkVersionInt()
	} else {
	return FutureApiLevel
	}
	}

	func (c *config) AppsDefaultVersionName() string {
	return String(c.ProductVariables.AppsDefaultVersionName)
	}

	// Codenames that are active in the current lunch target.
	func (c *config) PlatformVersionActiveCodenames() []string {
	return c.ProductVariables.Platform_version_active_codenames
	}

	// Codenames that are available in the branch but not included in the current
	// lunch target.
	func (c *config) PlatformVersionFutureCodenames() []string {
	return c.ProductVariables.Platform_version_future_codenames
	}

	// All possible codenames in the current branch. NB: Not named AllCodenames
	// because "all" has historically meant "active" in make, and still does in
	// build.prop.
	func (c *config) PlatformVersionCombinedCodenames() []string {
	combined := []string{}
	combined = append(combined, c.PlatformVersionActiveCodenames()...)
	combined = append(combined, c.PlatformVersionFutureCodenames()...)
	return combined
	}

	func (c *config) ProductAAPTConfig() []string {
	return stringSlice(c.ProductVariables.AAPTConfig)
	}

	func (c *config) ProductAAPTPreferredConfig() string {
	return String(c.ProductVariables.AAPTPreferredConfig)
	}

	func (c *config) ProductAAPTCharacteristics() string {
	return String(c.ProductVariables.AAPTCharacteristics)
	}

	func (c *config) ProductAAPTPrebuiltDPI() []string {
	return stringSlice(c.ProductVariables.AAPTPrebuiltDPI)
	}

	func (c *config) DefaultAppCertificateDir(ctx PathContext) SourcePath {
	defaultCert := String(c.ProductVariables.DefaultAppCertificate)
	if defaultCert != "" {
	return PathForSource(ctx, filepath.Dir(defaultCert))
	} else {
	return PathForSource(ctx, "build/target/product/security")
	}
	}

	func (c *config) DefaultAppCertificate(ctx PathContext) (pem, key SourcePath) {
	defaultCert := String(c.ProductVariables.DefaultAppCertificate)
	if defaultCert != "" {
	return PathForSource(ctx, defaultCert+".x509.pem"), PathForSource(ctx, defaultCert+".pk8")
	} else {
	defaultDir := c.DefaultAppCertificateDir(ctx)
	return defaultDir.Join(ctx, "testkey.x509.pem"), defaultDir.Join(ctx, "testkey.pk8")
	}
	}

	func (c *config) AllowMissingDependencies() bool {
	return Bool(c.ProductVariables.Allow_missing_dependencies)
	}

	func (c *config) UnbundledBuild() bool {
	return Bool(c.ProductVariables.Unbundled_build)
	}

	func (c *config) IsPdkBuild() bool {
	return Bool(c.ProductVariables.Pdk)
	}

	func (c *config) MinimizeJavaDebugInfo() bool {
	return Bool(c.ProductVariables.MinimizeJavaDebugInfo) && !Bool(c.ProductVariables.Eng)
	}

	func (c *config) DevicePrefer32BitExecutables() bool {
	return Bool(c.ProductVariables.DevicePrefer32BitExecutables)
	}

	func (c *config) SkipDeviceInstall() bool {
	return c.EmbeddedInMake()
	}

	func (c *config) SkipMegaDeviceInstall(path string) bool {
	return Bool(c.Mega_device) &&
	strings.HasPrefix(path, filepath.Join(c.buildDir, "target", "product"))
	}

	func (c *config) SanitizeHost() []string {
	return append([]string(nil), c.ProductVariables.SanitizeHost...)
	}

	func (c *config) SanitizeDevice() []string {
	return append([]string(nil), c.ProductVariables.SanitizeDevice...)
	}

	func (c *config) SanitizeDeviceDiag() []string {
	return append([]string(nil), c.ProductVariables.SanitizeDeviceDiag...)
	}

	func (c *config) SanitizeDeviceArch() []string {
	return append([]string(nil), c.ProductVariables.SanitizeDeviceArch...)
	}

	func (c *config) EnableCFI() bool {
	if c.ProductVariables.EnableCFI == nil {
	return true
	} else {
	return *c.ProductVariables.EnableCFI
	}
	}

	func (c *config) Android64() bool {
	for _, t := range c.Targets[Device] {
	if t.Arch.ArchType.Multilib == "lib64" {
	return true
	}
	}

	return false
	}

	func (c *config) UseD8Desugar() bool {
	return !c.IsEnvFalse("USE_D8_DESUGAR")
	}

	func (c *config) UseGoma() bool {
	return Bool(c.ProductVariables.UseGoma)
	}

	// Returns true if OpenJDK9 prebuilts are being used
	func (c *config) UseOpenJDK9() bool {
	return c.useOpenJDK9
	}

	// Returns true if -source 1.9 -target 1.9 is being passed to javac
	func (c *config) TargetOpenJDK9() bool {
	return c.targetOpenJDK9
	}

	func (c *config) ClangTidy() bool {
	return Bool(c.ProductVariables.ClangTidy)
	}

	func (c *config) TidyChecks() string {
	if c.ProductVariables.TidyChecks == nil {
	return ""
	}
	return *c.ProductVariables.TidyChecks
	}

	func (c *config) LibartImgHostBaseAddress() string {
	return "0x60000000"
	}

	func (c *config) LibartImgDeviceBaseAddress() string {
	archType := Common
	if len(c.Targets[Device]) > 0 {
	archType = c.Targets[Device][0].Arch.ArchType
	}
	switch archType {
	default:
	return "0x70000000"
	case Mips, Mips64:
	return "0x5C000000"
	}
	}

	func (c *config) ArtUseReadBarrier() bool {
	return Bool(c.ProductVariables.ArtUseReadBarrier)
	}

	func (c *deviceConfig) Arches() []Arch {
	var arches []Arch
	for _, target := range c.config.Targets[Device] {
	arches = append(arches, target.Arch)
	}
	return arches
	}

	func (c *deviceConfig) VendorPath() string {
	if c.config.ProductVariables.VendorPath != nil {
	return *c.config.ProductVariables.VendorPath
	}
	return "vendor"
	}

	func (c *deviceConfig) VndkVersion() string {
	return String(c.config.ProductVariables.DeviceVndkVersion)
	}

	func (c *deviceConfig) PlatformVndkVersion() string {
	return String(c.config.ProductVariables.Platform_vndk_version)
	}

	func (c *deviceConfig) ExtraVndkVersions() []string {
	return c.config.ProductVariables.ExtraVndkVersions
	}

	func (c *deviceConfig) SystemSdkVersions() []string {
	if c.config.ProductVariables.DeviceSystemSdkVersions == nil {
	return nil
	}
	return *c.config.ProductVariables.DeviceSystemSdkVersions
	}

	func (c *deviceConfig) PlatformSystemSdkVersions() []string {
	return c.config.ProductVariables.Platform_systemsdk_versions
	}

	func (c *deviceConfig) OdmPath() string {
	if c.config.ProductVariables.OdmPath != nil {
	return *c.config.ProductVariables.OdmPath
	}
	return "odm"
	}

	func (c *deviceConfig) ProductPath() string {
	if c.config.ProductVariables.ProductPath != nil {
	return *c.config.ProductVariables.ProductPath
	}
	return "product"
	}

	func (c *deviceConfig) BtConfigIncludeDir() string {
	return String(c.config.ProductVariables.BtConfigIncludeDir)
	}

	func (c *deviceConfig) DeviceKernelHeaderDirs() []string {
	return c.config.ProductVariables.DeviceKernelHeaders
	}

	func (c *deviceConfig) NativeCoverageEnabled() bool {
	return Bool(c.config.ProductVariables.NativeCoverage)
	}

	func (c *deviceConfig) CoverageEnabledForPath(path string) bool {
	coverage := false
	if c.config.ProductVariables.CoveragePaths != nil {
	if PrefixInList(path, *c.config.ProductVariables.CoveragePaths) {
	coverage = true
	}
	}
	if coverage && c.config.ProductVariables.CoverageExcludePaths != nil {
	if PrefixInList(path, *c.config.ProductVariables.CoverageExcludePaths) {
	coverage = false
	}
	}
	return coverage
	}

	func (c *deviceConfig) PgoAdditionalProfileDirs() []string {
	return c.config.ProductVariables.PgoAdditionalProfileDirs
	}

	func (c *config) IntegerOverflowDisabledForPath(path string) bool {
	if c.ProductVariables.IntegerOverflowExcludePaths == nil {
	return false
	}
	return PrefixInList(path, *c.ProductVariables.IntegerOverflowExcludePaths)
	}

	func (c *config) CFIDisabledForPath(path string) bool {
	if c.ProductVariables.CFIExcludePaths == nil {
	return false
	}
	return PrefixInList(path, *c.ProductVariables.CFIExcludePaths)
	}

	func (c *config) CFIEnabledForPath(path string) bool {
	if c.ProductVariables.CFIIncludePaths == nil {
	return false
	}
	return PrefixInList(path, *c.ProductVariables.CFIIncludePaths)
	}

	func stringSlice(s *[]string) []string {
	if s != nil {
	return *s
	} else {
	return nil
	}
	}