ui/build/kati.go - android_build_soong - Gitiles

 // Copyright 2017 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 build

 import (
 	"android/soong/ui/metrics"
 	"android/soong/ui/status"
 	"crypto/md5"
 	"fmt"
 	"io/ioutil"
 	"os"
 	"os/user"
 	"path/filepath"
 	"strings"
 )

 var spaceSlashReplacer = strings.NewReplacer("/", "_", " ", "_")

 const katiBuildSuffix = ""
 const katiCleanspecSuffix = "-cleanspec"
 const katiPackageSuffix = "-package"

 // genKatiSuffix creates a filename suffix for kati-generated files so that we
 // can cache them based on their inputs. Such files include the generated Ninja
 // files and env.sh environment variable setup files.
 //
 // The filename suffix should encode all common changes to Kati inputs.
 // Currently that includes the TARGET_PRODUCT and kati-processed command line
 // arguments.
 func genKatiSuffix(ctx Context, config Config) {
 	// Construct the base suffix.
 	katiSuffix := "-" + config.TargetProduct()

 	// Append kati arguments to the suffix.
 	if args := config.KatiArgs(); len(args) > 0 {
 		katiSuffix += "-" + spaceSlashReplacer.Replace(strings.Join(args, "_"))
 	}

 	// If the suffix is too long, replace it with a md5 hash and write a
 	// file that contains the original suffix.
 	if len(katiSuffix) > 64 {
 		shortSuffix := "-" + fmt.Sprintf("%x", md5.Sum([]byte(katiSuffix)))
 		config.SetKatiSuffix(shortSuffix)

 		ctx.Verbosef("Kati ninja suffix too long: %q", katiSuffix)
 		ctx.Verbosef("Replacing with: %q", shortSuffix)

 		if err := ioutil.WriteFile(strings.TrimSuffix(config.KatiBuildNinjaFile(), "ninja")+"suf", []byte(katiSuffix), 0777); err != nil {
 			ctx.Println("Error writing suffix file:", err)
 		}
 	} else {
 		config.SetKatiSuffix(katiSuffix)
 	}
 }

 func writeValueIfChanged(ctx Context, config Config, dir string, filename string, value string) {
 	filePath := filepath.Join(dir, filename)
 	previousValue := ""
 	rawPreviousValue, err := ioutil.ReadFile(filePath)
 	if err == nil {
 		previousValue = string(rawPreviousValue)
 	}

 	if previousValue != value {
 		if err = ioutil.WriteFile(filePath, []byte(value), 0666); err != nil {
 			ctx.Fatalf("Failed to write: %v", err)
 		}
 	}
 }

 // Base function to construct and run the Kati command line with additional
 // arguments, and a custom function closure to mutate the environment Kati runs
 // in.
 func runKati(ctx Context, config Config, extraSuffix string, args []string, envFunc func(*Environment)) {
 	executable := config.PrebuiltBuildTool("ckati")
 	// cKati arguments.
 	args = append([]string{
 		// Instead of executing commands directly, generate a Ninja file.
 		"--ninja",
 		// Generate Ninja files in the output directory.
 		"--ninja_dir=" + config.OutDir(),
 		// Filename suffix of the generated Ninja file.
 		"--ninja_suffix=" + config.KatiSuffix() + extraSuffix,
 		// Remove common parts at the beginning of a Ninja file, like build_dir,
 		// local_pool and _kati_always_build_. Allows Kati to be run multiple
 		// times, with generated Ninja files combined in a single invocation
 		// using 'include'.
 		"--no_ninja_prelude",
 		// Support declaring phony outputs in AOSP Ninja.
 		"--use_ninja_phony_output",
 		// Regenerate the Ninja file if environment inputs have changed. e.g.
 		// CLI flags, .mk file timestamps, env vars, $(wildcard ..) and some
 		// $(shell ..) results.
 		"--regen",
 		// Skip '-include' directives starting with the specified path. Used to
 		// ignore generated .mk files.
 		"--ignore_optional_include=" + filepath.Join(config.OutDir(), "%.P"),
 		// Detect the use of $(shell echo ...).
 		"--detect_android_echo",
 		// Colorful ANSI-based warning and error messages.
 		"--color_warnings",
 		// Generate all targets, not just the top level requested ones.
 		"--gen_all_targets",
 		// Use the built-in emulator of GNU find for better file finding
 		// performance. Used with $(shell find ...).
 		"--use_find_emulator",
 		// Fail when the find emulator encounters problems.
 		"--werror_find_emulator",
 		// Do not provide any built-in rules.
 		"--no_builtin_rules",
 		// Fail when suffix rules are used.
 		"--werror_suffix_rules",
 		// Fail when a real target depends on a phony target.
 		"--werror_real_to_phony",
 		// Makes real_to_phony checks assume that any top-level or leaf
 		// dependencies that does *not* have a '/' in it is a phony target.
 		"--top_level_phony",
 		// Fail when a phony target contains slashes.
 		"--werror_phony_looks_real",
 		// Fail when writing to a read-only directory.
 		"--werror_writable",
 		// Print Kati's internal statistics, such as the number of variables,
 		// implicit/explicit/suffix rules, and so on.
 		"--kati_stats",
 	}, args...)

 	// Generate a minimal Ninja file.
 	//
 	// Used for build_test and multiproduct_kati, which runs Kati several
 	// hundred times for different configurations to test file generation logic.
 	// These can result in generating Ninja files reaching ~1GB or more,
 	// resulting in ~hundreds of GBs of writes.
 	//
 	// Since we don't care about executing the Ninja files in these test cases,
 	// generating the Ninja file content wastes time, so skip writing any
 	// information out with --empty_ninja_file.
 	//
 	// From https://github.com/google/kati/commit/87b8da7af2c8bea28b1d8ab17679453d859f96e5
 	if config.EmptyNinjaFile() {
 		args = append(args, "--empty_ninja_file")
 	}

 	// Apply 'local_pool' to to all rules that don't specify a pool.
 	if config.UseRemoteBuild() {
 		args = append(args, "--default_pool=local_pool")
 	}

 	cmd := Command(ctx, config, "ckati", executable, args...)

 	// Set up the nsjail sandbox.
 	cmd.Sandbox = katiSandbox

 	// Set up stdout and stderr.
 	pipe, err := cmd.StdoutPipe()
 	if err != nil {
 		ctx.Fatalln("Error getting output pipe for ckati:", err)
 	}
 	cmd.Stderr = cmd.Stdout

 	var username string
 	// Pass on various build environment metadata to Kati.
 	if usernameFromEnv, ok := cmd.Environment.Get("BUILD_USERNAME"); !ok {
 		username = "unknown"
 		if u, err := user.Current(); err == nil {
 			username = u.Username
 		} else {
 			ctx.Println("Failed to get current user:", err)
 		}
 		cmd.Environment.Set("BUILD_USERNAME", username)
 	} else {
 		username = usernameFromEnv
 	}

 	hostname, ok := cmd.Environment.Get("BUILD_HOSTNAME")
 	// Unset BUILD_HOSTNAME during kati run to avoid kati rerun, kati will use BUILD_HOSTNAME from a file.
 	cmd.Environment.Unset("BUILD_HOSTNAME")
 	if !ok {
 		hostname, err = os.Hostname()
 		if err != nil {
 			ctx.Println("Failed to read hostname:", err)
 			hostname = "unknown"
 		}
 	}
 	writeValueIfChanged(ctx, config, config.SoongOutDir(), "build_hostname.txt", hostname)
 	_, ok = cmd.Environment.Get("BUILD_NUMBER")
 	// Unset BUILD_NUMBER during kati run to avoid kati rerun, kati will use BUILD_NUMBER from a file.
 	cmd.Environment.Unset("BUILD_NUMBER")
 	if ok {
 		cmd.Environment.Set("HAS_BUILD_NUMBER", "true")
 	} else {
 		cmd.Environment.Set("HAS_BUILD_NUMBER", "false")
 	}

 	// Apply the caller's function closure to mutate the environment variables.
 	envFunc(cmd.Environment)

 	cmd.StartOrFatal()
 	// Set up the ToolStatus command line reader for Kati for a consistent UI
 	// for the user.
 	status.KatiReader(ctx.Status.StartTool(), pipe)
 	cmd.WaitOrFatal()
 }

 func runKatiBuild(ctx Context, config Config) {
 	ctx.BeginTrace(metrics.RunKati, "kati build")
 	defer ctx.EndTrace()

 	args := []string{
 		// Mark the output directory as writable.
 		"--writable", config.OutDir() + "/",
 		// Fail when encountering implicit rules. e.g.
 		// %.foo: %.bar
 		//   cp $< $@
 		"--werror_implicit_rules",
 		// Entry point for the Kati Ninja file generation.
 		"-f", "build/make/core/main.mk",
 	}

 	if !config.BuildBrokenDupRules() {
 		// Fail when redefining / duplicating a target.
 		args = append(args, "--werror_overriding_commands")
 	}

 	args = append(args, config.KatiArgs()...)

 	args = append(args,
 		// Location of the Make vars .mk file generated by Soong.
 		"SOONG_MAKEVARS_MK="+config.SoongMakeVarsMk(),
 		// Location of the Android.mk file generated by Soong. This
 		// file contains Soong modules represented as Kati modules,
 		// allowing Kati modules to depend on Soong modules.
 		"SOONG_ANDROID_MK="+config.SoongAndroidMk(),
 		// Directory containing outputs for the target device.
 		"TARGET_DEVICE_DIR="+config.TargetDeviceDir(),
 		// Directory containing .mk files for packaging purposes, such as
 		// the dist.mk file, containing dist-for-goals data.
 		"KATI_PACKAGE_MK_DIR="+config.KatiPackageMkDir())

 	runKati(ctx, config, katiBuildSuffix, args, func(env *Environment) {})

 	// compress and dist the main build ninja file.
 	distGzipFile(ctx, config, config.KatiBuildNinjaFile())

 	// Cleanup steps.
 	cleanCopyHeaders(ctx, config)
 	cleanOldInstalledFiles(ctx, config)
 }

 // Clean out obsolete header files on the disk that were *not copied* during the
 // build with BUILD_COPY_HEADERS and LOCAL_COPY_HEADERS.
 //
 // These should be increasingly uncommon, as it's a deprecated feature and there
 // isn't an equivalent feature in Soong.
 func cleanCopyHeaders(ctx Context, config Config) {
 	ctx.BeginTrace("clean", "clean copy headers")
 	defer ctx.EndTrace()

 	// Read and parse the list of copied headers from a file in the product
 	// output directory.
 	data, err := ioutil.ReadFile(filepath.Join(config.ProductOut(), ".copied_headers_list"))
 	if err != nil {
 		if os.IsNotExist(err) {
 			return
 		}
 		ctx.Fatalf("Failed to read copied headers list: %v", err)
 	}

 	headers := strings.Fields(string(data))
 	if len(headers) < 1 {
 		ctx.Fatal("Failed to parse copied headers list: %q", string(data))
 	}
 	headerDir := headers[0]
 	headers = headers[1:]

 	// Walk the tree and remove any headers that are not in the list of copied
 	// headers in the current build.
 	filepath.Walk(headerDir,
 		func(path string, info os.FileInfo, err error) error {
 			if err != nil {
 				return nil
 			}
 			if info.IsDir() {
 				return nil
 			}
 			if !inList(path, headers) {
 				ctx.Printf("Removing obsolete header %q", path)
 				if err := os.Remove(path); err != nil {
 					ctx.Fatalf("Failed to remove obsolete header %q: %v", path, err)
 				}
 			}
 			return nil
 		})
 }

 // Clean out any previously installed files from the disk that are not installed
 // in the current build.
 func cleanOldInstalledFiles(ctx Context, config Config) {
 	ctx.BeginTrace("clean", "clean old installed files")
 	defer ctx.EndTrace()

 	// We shouldn't be removing files from one side of the two-step asan builds
 	var suffix string
 	if v, ok := config.Environment().Get("SANITIZE_TARGET"); ok {
 		if sanitize := strings.Fields(v); inList("address", sanitize) {
 			suffix = "_asan"
 		}
 	}

 	cleanOldFiles(ctx, config.ProductOut(), ".installable_files"+suffix)

 	cleanOldFiles(ctx, config.HostOut(), ".installable_test_files")
 }

 // Generate the Ninja file containing the packaging command lines for the dist
 // dir.
 func runKatiPackage(ctx Context, config Config) {
 	ctx.BeginTrace(metrics.RunKati, "kati package")
 	defer ctx.EndTrace()

 	args := []string{
 		// Mark the dist dir as writable.
 		"--writable", config.DistDir() + "/",
 		// Fail when encountering implicit rules. e.g.
 		"--werror_implicit_rules",
 		// Fail when redefining / duplicating a target.
 		"--werror_overriding_commands",
 		// Entry point.
 		"-f", "build/make/packaging/main.mk",
 		// Directory containing .mk files for packaging purposes, such as
 		// the dist.mk file, containing dist-for-goals data.
 		"KATI_PACKAGE_MK_DIR=" + config.KatiPackageMkDir(),
 	}

 	// Run Kati against a restricted set of environment variables.
 	runKati(ctx, config, katiPackageSuffix, args, func(env *Environment) {
 		env.Allow([]string{
 			// Some generic basics
 			"LANG",
 			"LC_MESSAGES",
 			"PATH",
 			"PWD",
 			"TMPDIR",

 			// Tool configs
 			"ASAN_SYMBOLIZER_PATH",
 			"JAVA_HOME",
 			"PYTHONDONTWRITEBYTECODE",

 			// Build configuration
 			"ANDROID_BUILD_SHELL",
 			"DIST_DIR",
 			"OUT_DIR",
 			"FILE_NAME_TAG",
 		}...)

 		if config.Dist() {
 			env.Set("DIST", "true")
 			env.Set("DIST_DIR", config.DistDir())
 		}
 	})

 	// Compress and dist the packaging Ninja file.
 	distGzipFile(ctx, config, config.KatiPackageNinjaFile())
 }

 // Run Kati on the cleanspec files to clean the build.
 func runKatiCleanSpec(ctx Context, config Config) {
 	ctx.BeginTrace(metrics.RunKati, "kati cleanspec")
 	defer ctx.EndTrace()

 	runKati(ctx, config, katiCleanspecSuffix, []string{
 		// Fail when encountering implicit rules. e.g.
 		"--werror_implicit_rules",
 		// Fail when redefining / duplicating a target.
 		"--werror_overriding_commands",
 		// Entry point.
 		"-f", "build/make/core/cleanbuild.mk",
 		"SOONG_MAKEVARS_MK=" + config.SoongMakeVarsMk(),
 		"TARGET_DEVICE_DIR=" + config.TargetDeviceDir(),
 	}, func(env *Environment) {})
 }
	// Copyright 2017 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 build

	import (
	"android/soong/ui/metrics"
	"android/soong/ui/status"
	"crypto/md5"
	"fmt"
	"io/ioutil"
	"os"
	"os/user"
	"path/filepath"
	"strings"
	)

	var spaceSlashReplacer = strings.NewReplacer("/", "_", " ", "_")

	const katiBuildSuffix = ""
	const katiCleanspecSuffix = "-cleanspec"
	const katiPackageSuffix = "-package"

	// genKatiSuffix creates a filename suffix for kati-generated files so that we
	// can cache them based on their inputs. Such files include the generated Ninja
	// files and env.sh environment variable setup files.
	//
	// The filename suffix should encode all common changes to Kati inputs.
	// Currently that includes the TARGET_PRODUCT and kati-processed command line
	// arguments.
	func genKatiSuffix(ctx Context, config Config) {
	// Construct the base suffix.
	katiSuffix := "-" + config.TargetProduct()

	// Append kati arguments to the suffix.
	if args := config.KatiArgs(); len(args) > 0 {
	katiSuffix += "-" + spaceSlashReplacer.Replace(strings.Join(args, "_"))
	}

	// If the suffix is too long, replace it with a md5 hash and write a
	// file that contains the original suffix.
	if len(katiSuffix) > 64 {
	shortSuffix := "-" + fmt.Sprintf("%x", md5.Sum([]byte(katiSuffix)))
	config.SetKatiSuffix(shortSuffix)

	ctx.Verbosef("Kati ninja suffix too long: %q", katiSuffix)
	ctx.Verbosef("Replacing with: %q", shortSuffix)

	if err := ioutil.WriteFile(strings.TrimSuffix(config.KatiBuildNinjaFile(), "ninja")+"suf", []byte(katiSuffix), 0777); err != nil {
	ctx.Println("Error writing suffix file:", err)
	}
	} else {
	config.SetKatiSuffix(katiSuffix)
	}
	}

	func writeValueIfChanged(ctx Context, config Config, dir string, filename string, value string) {
	filePath := filepath.Join(dir, filename)
	previousValue := ""
	rawPreviousValue, err := ioutil.ReadFile(filePath)
	if err == nil {
	previousValue = string(rawPreviousValue)
	}

	if previousValue != value {
	if err = ioutil.WriteFile(filePath, []byte(value), 0666); err != nil {
	ctx.Fatalf("Failed to write: %v", err)
	}
	}
	}

	// Base function to construct and run the Kati command line with additional
	// arguments, and a custom function closure to mutate the environment Kati runs
	// in.
	func runKati(ctx Context, config Config, extraSuffix string, args []string, envFunc func(*Environment)) {
	executable := config.PrebuiltBuildTool("ckati")
	// cKati arguments.
	args = append([]string{
	// Instead of executing commands directly, generate a Ninja file.
	"--ninja",
	// Generate Ninja files in the output directory.
	"--ninja_dir=" + config.OutDir(),
	// Filename suffix of the generated Ninja file.
	"--ninja_suffix=" + config.KatiSuffix() + extraSuffix,
	// Remove common parts at the beginning of a Ninja file, like build_dir,
	// local_pool and _kati_always_build_. Allows Kati to be run multiple
	// times, with generated Ninja files combined in a single invocation
	// using 'include'.
	"--no_ninja_prelude",
	// Support declaring phony outputs in AOSP Ninja.
	"--use_ninja_phony_output",
	// Regenerate the Ninja file if environment inputs have changed. e.g.
	// CLI flags, .mk file timestamps, env vars, $(wildcard ..) and some
	// $(shell ..) results.
	"--regen",
	// Skip '-include' directives starting with the specified path. Used to
	// ignore generated .mk files.
	"--ignore_optional_include=" + filepath.Join(config.OutDir(), "%.P"),
	// Detect the use of $(shell echo ...).
	"--detect_android_echo",
	// Colorful ANSI-based warning and error messages.
	"--color_warnings",
	// Generate all targets, not just the top level requested ones.
	"--gen_all_targets",
	// Use the built-in emulator of GNU find for better file finding
	// performance. Used with $(shell find ...).
	"--use_find_emulator",
	// Fail when the find emulator encounters problems.
	"--werror_find_emulator",
	// Do not provide any built-in rules.
	"--no_builtin_rules",
	// Fail when suffix rules are used.
	"--werror_suffix_rules",
	// Fail when a real target depends on a phony target.
	"--werror_real_to_phony",
	// Makes real_to_phony checks assume that any top-level or leaf
	// dependencies that does not have a '/' in it is a phony target.
	"--top_level_phony",
	// Fail when a phony target contains slashes.
	"--werror_phony_looks_real",
	// Fail when writing to a read-only directory.
	"--werror_writable",
	// Print Kati's internal statistics, such as the number of variables,
	// implicit/explicit/suffix rules, and so on.
	"--kati_stats",
	}, args...)

	// Generate a minimal Ninja file.
	//
	// Used for build_test and multiproduct_kati, which runs Kati several
	// hundred times for different configurations to test file generation logic.
	// These can result in generating Ninja files reaching ~1GB or more,
	// resulting in ~hundreds of GBs of writes.
	//
	// Since we don't care about executing the Ninja files in these test cases,
	// generating the Ninja file content wastes time, so skip writing any
	// information out with --empty_ninja_file.
	//
	// From https://github.com/google/kati/commit/87b8da7af2c8bea28b1d8ab17679453d859f96e5
	if config.EmptyNinjaFile() {
	args = append(args, "--empty_ninja_file")
	}

	// Apply 'local_pool' to to all rules that don't specify a pool.
	if config.UseRemoteBuild() {
	args = append(args, "--default_pool=local_pool")
	}

	cmd := Command(ctx, config, "ckati", executable, args...)

	// Set up the nsjail sandbox.
	cmd.Sandbox = katiSandbox

	// Set up stdout and stderr.
	pipe, err := cmd.StdoutPipe()
	if err != nil {
	ctx.Fatalln("Error getting output pipe for ckati:", err)
	}
	cmd.Stderr = cmd.Stdout

	var username string
	// Pass on various build environment metadata to Kati.
	if usernameFromEnv, ok := cmd.Environment.Get("BUILD_USERNAME"); !ok {
	username = "unknown"
	if u, err := user.Current(); err == nil {
	username = u.Username
	} else {
	ctx.Println("Failed to get current user:", err)
	}
	cmd.Environment.Set("BUILD_USERNAME", username)
	} else {
	username = usernameFromEnv
	}

	hostname, ok := cmd.Environment.Get("BUILD_HOSTNAME")
	// Unset BUILD_HOSTNAME during kati run to avoid kati rerun, kati will use BUILD_HOSTNAME from a file.
	cmd.Environment.Unset("BUILD_HOSTNAME")
	if !ok {
	hostname, err = os.Hostname()
	if err != nil {
	ctx.Println("Failed to read hostname:", err)
	hostname = "unknown"
	}
	}
	writeValueIfChanged(ctx, config, config.SoongOutDir(), "build_hostname.txt", hostname)
	_, ok = cmd.Environment.Get("BUILD_NUMBER")
	// Unset BUILD_NUMBER during kati run to avoid kati rerun, kati will use BUILD_NUMBER from a file.
	cmd.Environment.Unset("BUILD_NUMBER")
	if ok {
	cmd.Environment.Set("HAS_BUILD_NUMBER", "true")
	} else {
	cmd.Environment.Set("HAS_BUILD_NUMBER", "false")
	}

	// Apply the caller's function closure to mutate the environment variables.
	envFunc(cmd.Environment)

	cmd.StartOrFatal()
	// Set up the ToolStatus command line reader for Kati for a consistent UI
	// for the user.
	status.KatiReader(ctx.Status.StartTool(), pipe)
	cmd.WaitOrFatal()
	}

	func runKatiBuild(ctx Context, config Config) {
	ctx.BeginTrace(metrics.RunKati, "kati build")
	defer ctx.EndTrace()

	args := []string{
	// Mark the output directory as writable.
	"--writable", config.OutDir() + "/",
	// Fail when encountering implicit rules. e.g.
	// %.foo: %.bar
	// cp $< $@
	"--werror_implicit_rules",
	// Entry point for the Kati Ninja file generation.
	"-f", "build/make/core/main.mk",
	}

	if !config.BuildBrokenDupRules() {
	// Fail when redefining / duplicating a target.
	args = append(args, "--werror_overriding_commands")
	}

	args = append(args, config.KatiArgs()...)

	args = append(args,
	// Location of the Make vars .mk file generated by Soong.
	"SOONG_MAKEVARS_MK="+config.SoongMakeVarsMk(),
	// Location of the Android.mk file generated by Soong. This
	// file contains Soong modules represented as Kati modules,
	// allowing Kati modules to depend on Soong modules.
	"SOONG_ANDROID_MK="+config.SoongAndroidMk(),
	// Directory containing outputs for the target device.
	"TARGET_DEVICE_DIR="+config.TargetDeviceDir(),
	// Directory containing .mk files for packaging purposes, such as
	// the dist.mk file, containing dist-for-goals data.
	"KATI_PACKAGE_MK_DIR="+config.KatiPackageMkDir())

	runKati(ctx, config, katiBuildSuffix, args, func(env *Environment) {})

	// compress and dist the main build ninja file.
	distGzipFile(ctx, config, config.KatiBuildNinjaFile())

	// Cleanup steps.
	cleanCopyHeaders(ctx, config)
	cleanOldInstalledFiles(ctx, config)
	}

	// Clean out obsolete header files on the disk that were not copied during the
	// build with BUILD_COPY_HEADERS and LOCAL_COPY_HEADERS.
	//
	// These should be increasingly uncommon, as it's a deprecated feature and there
	// isn't an equivalent feature in Soong.
	func cleanCopyHeaders(ctx Context, config Config) {
	ctx.BeginTrace("clean", "clean copy headers")
	defer ctx.EndTrace()

	// Read and parse the list of copied headers from a file in the product
	// output directory.
	data, err := ioutil.ReadFile(filepath.Join(config.ProductOut(), ".copied_headers_list"))
	if err != nil {
	if os.IsNotExist(err) {
	return
	}
	ctx.Fatalf("Failed to read copied headers list: %v", err)
	}

	headers := strings.Fields(string(data))
	if len(headers) < 1 {
	ctx.Fatal("Failed to parse copied headers list: %q", string(data))
	}
	headerDir := headers[0]
	headers = headers[1:]

	// Walk the tree and remove any headers that are not in the list of copied
	// headers in the current build.
	filepath.Walk(headerDir,
	func(path string, info os.FileInfo, err error) error {
	if err != nil {
	return nil
	}
	if info.IsDir() {
	return nil
	}
	if !inList(path, headers) {
	ctx.Printf("Removing obsolete header %q", path)
	if err := os.Remove(path); err != nil {
	ctx.Fatalf("Failed to remove obsolete header %q: %v", path, err)
	}
	}
	return nil
	})
	}

	// Clean out any previously installed files from the disk that are not installed
	// in the current build.
	func cleanOldInstalledFiles(ctx Context, config Config) {
	ctx.BeginTrace("clean", "clean old installed files")
	defer ctx.EndTrace()

	// We shouldn't be removing files from one side of the two-step asan builds
	var suffix string
	if v, ok := config.Environment().Get("SANITIZE_TARGET"); ok {
	if sanitize := strings.Fields(v); inList("address", sanitize) {
	suffix = "_asan"
	}
	}

	cleanOldFiles(ctx, config.ProductOut(), ".installable_files"+suffix)

	cleanOldFiles(ctx, config.HostOut(), ".installable_test_files")
	}

	// Generate the Ninja file containing the packaging command lines for the dist
	// dir.
	func runKatiPackage(ctx Context, config Config) {
	ctx.BeginTrace(metrics.RunKati, "kati package")
	defer ctx.EndTrace()

	args := []string{
	// Mark the dist dir as writable.
	"--writable", config.DistDir() + "/",
	// Fail when encountering implicit rules. e.g.
	"--werror_implicit_rules",
	// Fail when redefining / duplicating a target.
	"--werror_overriding_commands",
	// Entry point.
	"-f", "build/make/packaging/main.mk",
	// Directory containing .mk files for packaging purposes, such as
	// the dist.mk file, containing dist-for-goals data.
	"KATI_PACKAGE_MK_DIR=" + config.KatiPackageMkDir(),
	}

	// Run Kati against a restricted set of environment variables.
	runKati(ctx, config, katiPackageSuffix, args, func(env *Environment) {
	env.Allow([]string{
	// Some generic basics
	"LANG",
	"LC_MESSAGES",
	"PATH",
	"PWD",
	"TMPDIR",

	// Tool configs
	"ASAN_SYMBOLIZER_PATH",
	"JAVA_HOME",
	"PYTHONDONTWRITEBYTECODE",

	// Build configuration
	"ANDROID_BUILD_SHELL",
	"DIST_DIR",
	"OUT_DIR",
	"FILE_NAME_TAG",
	}...)

	if config.Dist() {
	env.Set("DIST", "true")
	env.Set("DIST_DIR", config.DistDir())
	}
	})

	// Compress and dist the packaging Ninja file.
	distGzipFile(ctx, config, config.KatiPackageNinjaFile())
	}

	// Run Kati on the cleanspec files to clean the build.
	func runKatiCleanSpec(ctx Context, config Config) {
	ctx.BeginTrace(metrics.RunKati, "kati cleanspec")
	defer ctx.EndTrace()

	runKati(ctx, config, katiCleanspecSuffix, []string{
	// Fail when encountering implicit rules. e.g.
	"--werror_implicit_rules",
	// Fail when redefining / duplicating a target.
	"--werror_overriding_commands",
	// Entry point.
	"-f", "build/make/core/cleanbuild.mk",
	"SOONG_MAKEVARS_MK=" + config.SoongMakeVarsMk(),
	"TARGET_DEVICE_DIR=" + config.TargetDeviceDir(),
	}, func(env *Environment) {})
	}