Merge "Stubs variant is used when building for APEX" (421ba99e) · Commits · e / os / android_build_soong

Android.bp

+3 −0

Original line number	Diff line number	Diff line
		@@ -353,6 +353,9 @@ bootstrap_go_package {
		"apex/apex.go",
		"apex/key.go",
		],
		testSrcs: [
		"apex/apex_test.go",
		],
		pluginFor: ["soong_build"],
		}

android/apex.go

+64 −0

Original line number	Diff line number	Diff line
		@@ -14,6 +14,8 @@

		package android

		import "sync"

		// ApexModule is the interface that a module type is expected to implement if
		// the module has to be built differently depending on whether the module
		// is destined for an apex or not (installed to one of the regular partitions).
		@@ -94,6 +96,68 @@ func (m *ApexModuleBase) IsInstallableToApex() bool {
		return false
		}

		// This structure maps a module name to the set of APEX bundle names that the module
		// should be built for. Examples:
		//
		// ...["foo"]["bar"] == true: module foo is directly depended on by APEX bar
		// ...["foo"]["bar"] == false: module foo is indirectly depended on by APEX bar
		// ...["foo"]["bar"] doesn't exist: foo is not built for APEX bar
		// ...["foo"] doesn't exist: foo is not built for any APEX
		func apexBundleNamesMap(config Config) map[string]map[string]bool {
		return config.Once("apexBundleNames", func() interface{} {
		return make(map[string]map[string]bool)
		}).(map[string]map[string]bool)
		}

		var bundleNamesMapMutex sync.Mutex

		// Mark that a module named moduleName should be built for an apex named bundleName
		// directDep should be set to true if the module is a direct dependency of the apex.
		func BuildModuleForApexBundle(ctx BaseModuleContext, moduleName string, bundleName string, directDep bool) {
		bundleNamesMapMutex.Lock()
		defer bundleNamesMapMutex.Unlock()
		bundleNames, ok := apexBundleNamesMap(ctx.Config())[moduleName]
		if !ok {
		bundleNames = make(map[string]bool)
		apexBundleNamesMap(ctx.Config())[moduleName] = bundleNames
		}
		bundleNames[bundleName] = bundleNames[bundleName] \|\| directDep
		}

		// Returns the list of apex bundle names that the module named moduleName
		// should be built for.
		func GetApexBundlesForModule(ctx BaseModuleContext, moduleName string) map[string]bool {
		bundleNamesMapMutex.Lock()
		defer bundleNamesMapMutex.Unlock()
		return apexBundleNamesMap(ctx.Config())[moduleName]
		}

		// Tests if moduleName is directly depended on by bundleName (i.e. referenced in
		// native_shared_libs, etc.)
		func DirectlyInApex(config Config, bundleName string, moduleName string) bool {
		bundleNamesMapMutex.Lock()
		defer bundleNamesMapMutex.Unlock()
		if bundleNames, ok := apexBundleNamesMap(config)[moduleName]; ok {
		return bundleNames[bundleName]
		}
		return false
		}

		// Tests if moduleName is directly depended on by any APEX. If this returns true,
		// that means the module is part of the platform.
		func DirectlyInAnyApex(config Config, moduleName string) bool {
		bundleNamesMapMutex.Lock()
		defer bundleNamesMapMutex.Unlock()
		if bundleNames, ok := apexBundleNamesMap(config)[moduleName]; ok {
		for bn := range bundleNames {
		if bundleNames[bn] {
		return true
		}
		}
		}
		return false
		}

		func InitApexModule(m ApexModule) {
		base := m.apexModuleBase()
		base.canHaveApexVariants = true

apex/apex.go

+8 −14

Original line number	Diff line number	Diff line
		@@ -128,13 +128,6 @@ func init() {
		})
		}

		// maps a module name to set of apex bundle names that the module should be built for
		func apexBundleNamesFor(config android.Config) map[string]map[string]bool {
		return config.Once("apexBundleNames", func() interface{} {
		return make(map[string]map[string]bool)
		}).(map[string]map[string]bool)
		}

		// Mark the direct and transitive dependencies of apex bundles so that they
		// can be built for the apex bundles.
		func apexDepsMutator(mctx android.TopDownMutatorContext) {
		@@ -143,12 +136,9 @@ func apexDepsMutator(mctx android.TopDownMutatorContext) {
		mctx.WalkDeps(func(child, parent android.Module) bool {
		if am, ok := child.(android.ApexModule); ok && am.CanHaveApexVariants() {
		moduleName := mctx.OtherModuleName(am) + "-" + am.Target().String()
		bundleNames, ok := apexBundleNamesFor(mctx.Config())[moduleName]
		if !ok {
		bundleNames = make(map[string]bool)
		apexBundleNamesFor(mctx.Config())[moduleName] = bundleNames
		}
		bundleNames[apexBundleName] = true
		// If the parent is apexBundle, this child is directly depended.
		_, directDep := parent.(*apexBundle)
		android.BuildModuleForApexBundle(mctx, moduleName, apexBundleName, directDep)
		return true
		} else {
		return false
		@@ -161,7 +151,8 @@ func apexDepsMutator(mctx android.TopDownMutatorContext) {
		func apexMutator(mctx android.BottomUpMutatorContext) {
		if am, ok := mctx.Module().(android.ApexModule); ok && am.CanHaveApexVariants() {
		moduleName := mctx.ModuleName() + "-" + am.Target().String()
		if bundleNames, ok := apexBundleNamesFor(mctx.Config())[moduleName]; ok {
		bundleNames := android.GetApexBundlesForModule(mctx, moduleName)
		if len(bundleNames) > 0 {
		variations := []string{"platform"}
		for bn := range bundleNames {
		variations = append(variations, bn)
		@@ -495,6 +486,9 @@ func (a *apexBundle) GenerateAndroidBuildActions(ctx android.ModuleContext) {
		// indirect dependencies
		if am, ok := child.(android.ApexModule); ok && am.CanHaveApexVariants() && am.IsInstallableToApex() {
		if cc, ok := child.(*cc.Module); ok {
		if cc.IsStubs() \|\| cc.HasStubsVariants() {
		return false
		}
		depName := ctx.OtherModuleName(child)
		fileToCopy, dirInApex := getCopyManifestForNativeLibrary(cc)
		filesInfo = append(filesInfo, apexFile{fileToCopy, depName, cc.Arch().ArchType, dirInApex, nativeSharedLib})

apex/apex_test.go

0 → 100644

+369 −0

Original line number	Diff line number	Diff line
		// Copyright 2018 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 apex

		import (
		"android/soong/android"
		"android/soong/cc"
		"io/ioutil"
		"os"
		"strings"
		"testing"
		)

		func testApex(t testing.T, bp string) android.TestContext {
		config, buildDir := setup(t)
		defer teardown(buildDir)

		ctx := android.NewTestArchContext()
		ctx.RegisterModuleType("apex", android.ModuleFactoryAdaptor(apexBundleFactory))
		ctx.RegisterModuleType("apex_key", android.ModuleFactoryAdaptor(apexKeyFactory))

		ctx.PostDepsMutators(func(ctx android.RegisterMutatorsContext) {
		ctx.TopDown("apex_deps", apexDepsMutator)
		ctx.BottomUp("apex", apexMutator)
		})

		ctx.RegisterModuleType("cc_library", android.ModuleFactoryAdaptor(cc.LibraryFactory))
		ctx.RegisterModuleType("cc_library_shared", android.ModuleFactoryAdaptor(cc.LibrarySharedFactory))
		ctx.RegisterModuleType("cc_object", android.ModuleFactoryAdaptor(cc.ObjectFactory))
		ctx.RegisterModuleType("toolchain_library", android.ModuleFactoryAdaptor(cc.ToolchainLibraryFactory))
		ctx.PreDepsMutators(func(ctx android.RegisterMutatorsContext) {
		ctx.BottomUp("link", cc.LinkageMutator).Parallel()
		ctx.BottomUp("version", cc.VersionMutator).Parallel()
		ctx.BottomUp("begin", cc.BeginMutator).Parallel()
		})

		ctx.Register()

		bp = bp + `
		toolchain_library {
		name: "libcompiler_rt-extras",
		src: "",
		}

		toolchain_library {
		name: "libatomic",
		src: "",
		}

		toolchain_library {
		name: "libgcc",
		src: "",
		}

		toolchain_library {
		name: "libclang_rt.builtins-aarch64-android",
		src: "",
		}

		toolchain_library {
		name: "libclang_rt.builtins-arm-android",
		src: "",
		}

		cc_object {
		name: "crtbegin_so",
		stl: "none",
		}

		cc_object {
		name: "crtend_so",
		stl: "none",
		}

		`

		ctx.MockFileSystem(map[string][]byte{
		"Android.bp": []byte(bp),
		"testkey.avbpubkey": nil,
		"testkey.pem": nil,
		"build/target/product/security": nil,
		"apex_manifest.json": nil,
		"system/sepolicy/apex/myapex-file_contexts": nil,
		"mylib.cpp": nil,
		})
		_, errs := ctx.ParseFileList(".", []string{"Android.bp"})
		android.FailIfErrored(t, errs)
		_, errs = ctx.PrepareBuildActions(config)
		android.FailIfErrored(t, errs)

		return ctx
		}

		func setup(t *testing.T) (config android.Config, buildDir string) {
		buildDir, err := ioutil.TempDir("", "soong_apex_test")
		if err != nil {
		t.Fatal(err)
		}

		config = android.TestArchConfig(buildDir, nil)

		return
		}

		func teardown(buildDir string) {
		os.RemoveAll(buildDir)
		}

		// ensure that 'result' contains 'expected'
		func ensureContains(t *testing.T, result string, expected string) {
		if !strings.Contains(result, expected) {
		t.Errorf("%q is not found in %q", expected, result)
		}
		}

		// ensures that 'result' does not contain 'notExpected'
		func ensureNotContains(t *testing.T, result string, notExpected string) {
		if strings.Contains(result, notExpected) {
		t.Errorf("%q is found in %q", notExpected, result)
		}
		}

		func ensureListContains(t *testing.T, result []string, expected string) {
		if !android.InList(expected, result) {
		t.Errorf("%q is not found in %v", expected, result)
		}
		}

		func ensureListNotContains(t *testing.T, result []string, notExpected string) {
		if android.InList(notExpected, result) {
		t.Errorf("%q is found in %v", notExpected, result)
		}
		}

		// Minimal test
		func TestBasicApex(t *testing.T) {
		ctx := testApex(t, `
		apex {
		name: "myapex",
		key: "myapex.key",
		native_shared_libs: ["mylib"],
		}

		apex_key {
		name: "myapex.key",
		public_key: "testkey.avbpubkey",
		private_key: "testkey.pem",
		}

		cc_library {
		name: "mylib",
		srcs: ["mylib.cpp"],
		shared_libs: ["mylib2"],
		system_shared_libs: [],
		stl: "none",
		}

		cc_library {
		name: "mylib2",
		srcs: ["mylib.cpp"],
		system_shared_libs: [],
		stl: "none",
		}
		`)

		apexRule := ctx.ModuleForTests("myapex", "android_common_myapex").Rule("apexRule")
		copyCmds := apexRule.Args["copy_commands"]

		// Ensure that main rule creates an output
		ensureContains(t, apexRule.Output.String(), "myapex.apex.unsigned")

		// Ensure that apex variant is created for the direct dep
		ensureListContains(t, ctx.ModuleVariantsForTests("mylib"), "android_arm64_armv8-a_shared_myapex")

		// Ensure that apex variant is created for the indirect dep
		ensureListContains(t, ctx.ModuleVariantsForTests("mylib2"), "android_arm64_armv8-a_shared_myapex")

		// Ensure that both direct and indirect deps are copied into apex
		ensureContains(t, copyCmds, "image/lib64/mylib.so")
		ensureContains(t, copyCmds, "image/lib64/mylib2.so")
		}

		func TestApexWithStubs(t *testing.T) {
		ctx := testApex(t, `
		apex {
		name: "myapex",
		key: "myapex.key",
		native_shared_libs: ["mylib", "mylib3"],
		}

		apex_key {
		name: "myapex.key",
		public_key: "testkey.avbpubkey",
		private_key: "testkey.pem",
		}

		cc_library {
		name: "mylib",
		srcs: ["mylib.cpp"],
		shared_libs: ["mylib2", "mylib3"],
		system_shared_libs: [],
		stl: "none",
		}

		cc_library {
		name: "mylib2",
		srcs: ["mylib.cpp"],
		system_shared_libs: [],
		stl: "none",
		stubs: {
		versions: ["1", "2", "3"],
		},
		}

		cc_library {
		name: "mylib3",
		srcs: ["mylib.cpp"],
		system_shared_libs: [],
		stl: "none",
		stubs: {
		versions: ["10", "11", "12"],
		},
		}
		`)

		apexRule := ctx.ModuleForTests("myapex", "android_common_myapex").Rule("apexRule")
		copyCmds := apexRule.Args["copy_commands"]

		// Ensure that direct non-stubs dep is always included
		ensureContains(t, copyCmds, "image/lib64/mylib.so")

		// Ensure that indirect stubs dep is not included
		ensureNotContains(t, copyCmds, "image/lib64/mylib2.so")

		// Ensure that direct stubs dep is included
		ensureContains(t, copyCmds, "image/lib64/mylib3.so")

		mylibLdFlags := ctx.ModuleForTests("mylib", "android_arm64_armv8-a_shared_myapex").Rule("ld").Args["libFlags"]

		// Ensure that mylib is linking with the latest version of stubs for mylib2
		ensureContains(t, mylibLdFlags, "mylib2/android_arm64_armv8-a_shared_3_myapex/mylib2.so")
		// ... and not linking to the non-stub (impl) variant of mylib2
		ensureNotContains(t, mylibLdFlags, "mylib2/android_arm64_armv8-a_shared_myapex/mylib2.so")

		// Ensure that mylib is linking with the non-stub (impl) of mylib3 (because mylib3 is in the same apex)
		ensureContains(t, mylibLdFlags, "mylib3/android_arm64_armv8-a_shared_myapex/mylib3.so")
		// .. and not linking to the stubs variant of mylib3
		ensureNotContains(t, mylibLdFlags, "mylib3/android_arm64_armv8-a_shared_12_myapex/mylib3.so")
		}

		func TestApexWithSystemLibsStubs(t *testing.T) {
		ctx := testApex(t, `
		apex {
		name: "myapex",
		key: "myapex.key",
		native_shared_libs: ["mylib", "mylib_shared", "libdl", "libm"],
		}

		apex_key {
		name: "myapex.key",
		public_key: "testkey.avbpubkey",
		private_key: "testkey.pem",
		}

		cc_library {
		name: "mylib",
		srcs: ["mylib.cpp"],
		shared_libs: ["libdl#27"],
		stl: "none",
		}

		cc_library_shared {
		name: "mylib_shared",
		srcs: ["mylib.cpp"],
		shared_libs: ["libdl#27"],
		stl: "none",
		}

		cc_library {
		name: "libc",
		no_libgcc: true,
		nocrt: true,
		system_shared_libs: [],
		stl: "none",
		stubs: {
		versions: ["27", "28", "29"],
		},
		}

		cc_library {
		name: "libm",
		no_libgcc: true,
		nocrt: true,
		system_shared_libs: [],
		stl: "none",
		stubs: {
		versions: ["27", "28", "29"],
		},
		}

		cc_library {
		name: "libdl",
		no_libgcc: true,
		nocrt: true,
		system_shared_libs: [],
		stl: "none",
		stubs: {
		versions: ["27", "28", "29"],
		},
		}
		`)

		apexRule := ctx.ModuleForTests("myapex", "android_common_myapex").Rule("apexRule")
		copyCmds := apexRule.Args["copy_commands"]

		// Ensure that mylib, libm, libdl are included.
		ensureContains(t, copyCmds, "image/lib64/mylib.so")
		ensureContains(t, copyCmds, "image/lib64/libm.so")
		ensureContains(t, copyCmds, "image/lib64/libdl.so")

		// Ensure that libc is not included (since it has stubs and not listed in native_shared_libs)
		ensureNotContains(t, copyCmds, "image/lib64/libc.so")

		mylibLdFlags := ctx.ModuleForTests("mylib", "android_arm64_armv8-a_shared_myapex").Rule("ld").Args["libFlags"]
		mylibCFlags := ctx.ModuleForTests("mylib", "android_arm64_armv8-a_static_myapex").Rule("cc").Args["cFlags"]
		mylibSharedCFlags := ctx.ModuleForTests("mylib_shared", "android_arm64_armv8-a_shared_myapex").Rule("cc").Args["cFlags"]

		// For dependency to libc
		// Ensure that mylib is linking with the latest version of stubs
		ensureContains(t, mylibLdFlags, "libc/android_arm64_armv8-a_shared_29_myapex/libc.so")
		// ... and not linking to the non-stub (impl) variant
		ensureNotContains(t, mylibLdFlags, "libc/android_arm64_armv8-a_shared_myapex/libc.so")
		// ... Cflags from stub is correctly exported to mylib
		ensureContains(t, mylibCFlags, "__LIBC_API__=29")
		ensureContains(t, mylibSharedCFlags, "__LIBC_API__=29")

		// For dependency to libm
		// Ensure that mylib is linking with the non-stub (impl) variant
		ensureContains(t, mylibLdFlags, "libm/android_arm64_armv8-a_shared_myapex/libm.so")
		// ... and not linking to the stub variant
		ensureNotContains(t, mylibLdFlags, "libm/android_arm64_armv8-a_shared_29_myapex/libm.so")
		// ... and is not compiling with the stub
		ensureNotContains(t, mylibCFlags, "__LIBM_API__=29")
		ensureNotContains(t, mylibSharedCFlags, "__LIBM_API__=29")

		// For dependency to libdl
		// Ensure that mylib is linking with the specified version of stubs
		ensureContains(t, mylibLdFlags, "libdl/android_arm64_armv8-a_shared_27_myapex/libdl.so")
		// ... and not linking to the other versions of stubs
		ensureNotContains(t, mylibLdFlags, "libdl/android_arm64_armv8-a_shared_28_myapex/libdl.so")
		ensureNotContains(t, mylibLdFlags, "libdl/android_arm64_armv8-a_shared_29_myapex/libdl.so")
		// ... and not linking to the non-stub (impl) variant
		ensureNotContains(t, mylibLdFlags, "libdl/android_arm64_armv8-a_shared_myapex/libdl.so")
		// ... Cflags from stub is correctly exported to mylib
		ensureContains(t, mylibCFlags, "__LIBDL_API__=27")
		ensureContains(t, mylibSharedCFlags, "__LIBDL_API__=27")
		}

cc/cc.go

+96 −16

Original line number	Diff line number	Diff line
		@@ -39,7 +39,7 @@ func init() {
		ctx.BottomUp("vndk", vndkMutator).Parallel()
		ctx.BottomUp("ndk_api", ndkApiMutator).Parallel()
		ctx.BottomUp("test_per_src", testPerSrcMutator).Parallel()
		ctx.BottomUp("version", versionMutator).Parallel()
		ctx.BottomUp("version", VersionMutator).Parallel()
		ctx.BottomUp("begin", BeginMutator).Parallel()
		})

		@@ -248,6 +248,7 @@ type ModuleContextIntf interface {
		getVndkExtendsModuleName() string
		isPgoCompile() bool
		useClangLld(actx ModuleContext) bool
		isApex() bool
		}

		type ModuleContext interface {
		@@ -308,6 +309,8 @@ type dependencyTag struct {
		library bool

		reexportFlags bool

		explicitlyVersioned bool
		}

		var (
		@@ -511,6 +514,20 @@ func (c *Module) onlyInRecovery() bool {
		return c.ModuleBase.InstallInRecovery()
		}

		func (c *Module) IsStubs() bool {
		if library, ok := c.linker.(*libraryDecorator); ok {
		return library.buildStubs()
		}
		return false
		}

		func (c *Module) HasStubsVariants() bool {
		if library, ok := c.linker.(*libraryDecorator); ok {
		return len(library.Properties.Stubs.Versions) > 0
		}
		return false
		}

		type baseModuleContext struct {
		android.BaseContext
		moduleContextImpl
		@@ -649,6 +666,11 @@ func (ctx *moduleContextImpl) getVndkExtendsModuleName() string {
		return ctx.mod.getVndkExtendsModuleName()
		}

		// Tests if this module is built for APEX
		func (ctx *moduleContextImpl) isApex() bool {
		return ctx.mod.ApexName() != ""
		}

		func newBaseModule(hod android.HostOrDeviceSupported, multilib android.Multilib) *Module {
		return &Module{
		hod: hod,
		@@ -1081,6 +1103,30 @@ func (c *Module) DepsMutator(actx android.BottomUpMutatorContext) {
		{Mutator: "link", Variation: "static"},
		}, lateStaticDepTag, deps.LateStaticLibs...)

		addSharedLibDependencies := func(depTag dependencyTag, name string, version string) {
		var variations []blueprint.Variation
		variations = append(variations, blueprint.Variation{Mutator: "link", Variation: "shared"})
		versionVariantAvail := ctx.Os() == android.Android && !ctx.useVndk() && !c.inRecovery()
		if version != "" && versionVariantAvail {
		// Version is explicitly specified. i.e. libFoo#30
		variations = append(variations, blueprint.Variation{Mutator: "version", Variation: version})
		depTag.explicitlyVersioned = true
		}
		actx.AddVariationDependencies(variations, depTag, name)

		// If the version is not specified, add dependency to the latest stubs library.
		// The stubs library will be used when the depending module is built for APEX and
		// the dependent module is not in the same APEX.
		latestVersion := latestStubsVersionFor(actx.Config(), name)
		if version == "" && latestVersion != "" && versionVariantAvail {
		actx.AddVariationDependencies([]blueprint.Variation{
		{Mutator: "link", Variation: "shared"},
		{Mutator: "version", Variation: latestVersion},
		}, depTag, name)
		// Note that depTag.explicitlyVersioned is false in this case.
		}
		}

		// shared lib names without the #version suffix
		var sharedLibNames []string

		@@ -1091,29 +1137,17 @@ func (c *Module) DepsMutator(actx android.BottomUpMutatorContext) {
		if inList(lib, deps.ReexportSharedLibHeaders) {
		depTag = sharedExportDepTag
		}
		var variations []blueprint.Variation
		variations = append(variations, blueprint.Variation{Mutator: "link", Variation: "shared"})
		if version != "" && ctx.Os() == android.Android && !ctx.useVndk() && !c.inRecovery() {
		variations = append(variations, blueprint.Variation{Mutator: "version", Variation: version})
		}
		actx.AddVariationDependencies(variations, depTag, name)
		addSharedLibDependencies(depTag, name, version)
		}

		for _, lib := range deps.LateSharedLibs {
		name, version := stubsLibNameAndVersion(lib)
		if inList(name, sharedLibNames) {
		if inList(lib, sharedLibNames) {
		// This is to handle the case that some of the late shared libs (libc, libdl, libm, ...)
		// are added also to SharedLibs with version (e.g., libc#10). If not skipped, we will be
		// linking against both the stubs lib and the non-stubs lib at the same time.
		continue
		}
		depTag := lateSharedDepTag
		var variations []blueprint.Variation
		variations = append(variations, blueprint.Variation{Mutator: "link", Variation: "shared"})
		if version != "" && ctx.Os() == android.Android && !ctx.useVndk() && !c.inRecovery() {
		variations = append(variations, blueprint.Variation{Mutator: "version", Variation: version})
		}
		actx.AddVariationDependencies(variations, depTag, name)
		addSharedLibDependencies(lateSharedDepTag, lib, "")
		}

		actx.AddVariationDependencies([]blueprint.Variation{
		@@ -1372,7 +1406,53 @@ func (c *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
		return
		}
		}

		// Extract explicitlyVersioned field from the depTag and reset it inside the struct.
		// Otherwise, sharedDepTag and lateSharedDepTag with explicitlyVersioned set to true
		// won't be matched to sharedDepTag and lateSharedDepTag.
		explicitlyVersioned := false
		if t, ok := depTag.(dependencyTag); ok {
		explicitlyVersioned = t.explicitlyVersioned
		t.explicitlyVersioned = false
		depTag = t
		}

		if t, ok := depTag.(dependencyTag); ok && t.library {
		if dependentLibrary, ok := ccDep.linker.(*libraryDecorator); ok {
		depIsStubs := dependentLibrary.buildStubs()
		depHasStubs := ccDep.HasStubsVariants()
		depNameWithTarget := depName + "-" + ccDep.Target().String()
		depInSameApex := android.DirectlyInApex(ctx.Config(), c.ApexName(), depNameWithTarget)
		depInPlatform := !android.DirectlyInAnyApex(ctx.Config(), depNameWithTarget)

		var useThisDep bool
		if depIsStubs && explicitlyVersioned {
		// Always respect dependency to the versioned stubs (i.e. libX#10)
		useThisDep = true
		} else if !depHasStubs {
		// Use non-stub variant if that is the only choice
		// (i.e. depending on a lib without stubs.version property)
		useThisDep = true
		} else if c.IsForPlatform() {
		// If not building for APEX, use stubs only when it is from
		// an APEX (and not from platform)
		useThisDep = (depInPlatform != depIsStubs)
		if c.inRecovery() {
		// However, for recovery modules, since there is no APEX there,
		// always link to non-stub variant
		useThisDep = !depIsStubs
		}
		} else {
		// If building for APEX, use stubs only when it is not from
		// the same APEX
		useThisDep = (depInSameApex != depIsStubs)
		}

		if !useThisDep {
		return // stop processing this dep
		}
		}

		if i, ok := ccDep.linker.(exportedFlagsProducer); ok {
		flags := i.exportedFlags()
		deps := i.exportedFlagsDeps()