diff --git a/cc/Android.bp b/cc/Android.bp
index 88104e2..33f3db2 100644
--- a/cc/Android.bp
+++ b/cc/Android.bp
@@ -31,6 +31,7 @@
         "sanitize.go",
         "sabi.go",
         "sdk.go",
+        "snapshot_prebuilt.go",
         "snapshot_utils.go",
         "stl.go",
         "strip.go",
diff --git a/cc/cc.go b/cc/cc.go
index 986bf2b..7baaa66 100644
--- a/cc/cc.go
+++ b/cc/cc.go
@@ -1595,7 +1595,7 @@
 
 		// glob exported headers for snapshot, if BOARD_VNDK_VERSION is current.
 		if i, ok := c.linker.(snapshotLibraryInterface); ok && ctx.DeviceConfig().VndkVersion() == "current" {
-			if isSnapshotAware(ctx, c, apexInfo) {
+			if shouldCollectHeadersForSnapshot(ctx, c, apexInfo) {
 				i.collectHeadersForSnapshot(ctx)
 			}
 		}
diff --git a/cc/snapshot_prebuilt.go b/cc/snapshot_prebuilt.go
new file mode 100644
index 0000000..b291bd0
--- /dev/null
+++ b/cc/snapshot_prebuilt.go
@@ -0,0 +1,844 @@
+// Copyright 2020 The Android Open Source Project
+//
+// 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 cc
+
+// This file defines snapshot prebuilt modules, e.g. vendor snapshot and recovery snapshot. Such
+// snapshot modules will override original source modules with setting BOARD_VNDK_VERSION, with
+// snapshot mutators and snapshot information maps which are also defined in this file.
+
+import (
+	"strings"
+	"sync"
+
+	"android/soong/android"
+)
+
+// Defines the specifics of different images to which the snapshot process is applicable, e.g.,
+// vendor, recovery, ramdisk.
+type snapshotImage interface {
+	// Used to register callbacks with the build system.
+	init()
+
+	// Function that returns true if the module is included in this image.
+	// Using a function return instead of a value to prevent early
+	// evalution of a function that may be not be defined.
+	inImage(m *Module) func() bool
+
+	// Returns the value of the "available" property for a given module for
+	// and snapshot, e.g., "vendor_available", "recovery_available", etc.
+	// or nil if the property is not defined.
+	available(m *Module) *bool
+
+	// Returns true if a dir under source tree is an SoC-owned proprietary
+	// directory, such as device/, vendor/, etc.
+	//
+	// For a given snapshot (e.g., vendor, recovery, etc.) if
+	// isProprietaryPath(dir) returns true, then the module in dir will be
+	// built from sources.
+	isProprietaryPath(dir string) bool
+
+	// Whether to include VNDK in the snapshot for this image.
+	includeVndk() bool
+
+	// Whether a given module has been explicitly excluded from the
+	// snapshot, e.g., using the exclude_from_vendor_snapshot or
+	// exclude_from_recovery_snapshot properties.
+	excludeFromSnapshot(m *Module) bool
+}
+
+type vendorSnapshotImage struct{}
+type recoverySnapshotImage struct{}
+
+func (vendorSnapshotImage) init() {
+	android.RegisterSingletonType("vendor-snapshot", VendorSnapshotSingleton)
+	android.RegisterModuleType("vendor_snapshot_shared", VendorSnapshotSharedFactory)
+	android.RegisterModuleType("vendor_snapshot_static", VendorSnapshotStaticFactory)
+	android.RegisterModuleType("vendor_snapshot_header", VendorSnapshotHeaderFactory)
+	android.RegisterModuleType("vendor_snapshot_binary", VendorSnapshotBinaryFactory)
+	android.RegisterModuleType("vendor_snapshot_object", VendorSnapshotObjectFactory)
+}
+
+func (vendorSnapshotImage) inImage(m *Module) func() bool {
+	return m.inVendor
+}
+
+func (vendorSnapshotImage) available(m *Module) *bool {
+	return m.VendorProperties.Vendor_available
+}
+
+func (vendorSnapshotImage) isProprietaryPath(dir string) bool {
+	return isVendorProprietaryPath(dir)
+}
+
+// vendor snapshot includes static/header libraries with vndk: {enabled: true}.
+func (vendorSnapshotImage) includeVndk() bool {
+	return true
+}
+
+func (vendorSnapshotImage) excludeFromSnapshot(m *Module) bool {
+	return m.ExcludeFromVendorSnapshot()
+}
+
+func (recoverySnapshotImage) init() {
+	android.RegisterSingletonType("recovery-snapshot", RecoverySnapshotSingleton)
+	android.RegisterModuleType("recovery_snapshot_shared", RecoverySnapshotSharedFactory)
+	android.RegisterModuleType("recovery_snapshot_static", RecoverySnapshotStaticFactory)
+	android.RegisterModuleType("recovery_snapshot_header", RecoverySnapshotHeaderFactory)
+	android.RegisterModuleType("recovery_snapshot_binary", RecoverySnapshotBinaryFactory)
+	android.RegisterModuleType("recovery_snapshot_object", RecoverySnapshotObjectFactory)
+}
+
+func (recoverySnapshotImage) inImage(m *Module) func() bool {
+	return m.InRecovery
+}
+
+func (recoverySnapshotImage) available(m *Module) *bool {
+	return m.Properties.Recovery_available
+}
+
+func (recoverySnapshotImage) isProprietaryPath(dir string) bool {
+	return isRecoveryProprietaryPath(dir)
+}
+
+// recovery snapshot does NOT treat vndk specially.
+func (recoverySnapshotImage) includeVndk() bool {
+	return false
+}
+
+func (recoverySnapshotImage) excludeFromSnapshot(m *Module) bool {
+	return m.ExcludeFromRecoverySnapshot()
+}
+
+var vendorSnapshotImageSingleton vendorSnapshotImage
+var recoverySnapshotImageSingleton recoverySnapshotImage
+
+func init() {
+	vendorSnapshotImageSingleton.init()
+	recoverySnapshotImageSingleton.init()
+}
+
+const (
+	vendorSnapshotHeaderSuffix = ".vendor_header."
+	vendorSnapshotSharedSuffix = ".vendor_shared."
+	vendorSnapshotStaticSuffix = ".vendor_static."
+	vendorSnapshotBinarySuffix = ".vendor_binary."
+	vendorSnapshotObjectSuffix = ".vendor_object."
+)
+
+const (
+	recoverySnapshotHeaderSuffix = ".recovery_header."
+	recoverySnapshotSharedSuffix = ".recovery_shared."
+	recoverySnapshotStaticSuffix = ".recovery_static."
+	recoverySnapshotBinarySuffix = ".recovery_binary."
+	recoverySnapshotObjectSuffix = ".recovery_object."
+)
+
+var (
+	vendorSnapshotsLock         sync.Mutex
+	vendorSuffixModulesKey      = android.NewOnceKey("vendorSuffixModules")
+	vendorSnapshotHeaderLibsKey = android.NewOnceKey("vendorSnapshotHeaderLibs")
+	vendorSnapshotStaticLibsKey = android.NewOnceKey("vendorSnapshotStaticLibs")
+	vendorSnapshotSharedLibsKey = android.NewOnceKey("vendorSnapshotSharedLibs")
+	vendorSnapshotBinariesKey   = android.NewOnceKey("vendorSnapshotBinaries")
+	vendorSnapshotObjectsKey    = android.NewOnceKey("vendorSnapshotObjects")
+)
+
+// vendorSuffixModules holds names of modules whose vendor variants should have the vendor suffix.
+// This is determined by source modules, and then this will be used when exporting snapshot modules
+// to Makefile.
+//
+// For example, if libbase has "vendor_available: true", the name of core variant will be "libbase"
+// while the name of vendor variant will be "libbase.vendor". In such cases, the vendor snapshot of
+// "libbase" should be exported with the name "libbase.vendor".
+//
+// Refer to VendorSnapshotSourceMutator and makeLibName which use this.
+func vendorSuffixModules(config android.Config) map[string]bool {
+	return config.Once(vendorSuffixModulesKey, func() interface{} {
+		return make(map[string]bool)
+	}).(map[string]bool)
+}
+
+// these are vendor snapshot maps holding names of vendor snapshot modules
+func vendorSnapshotHeaderLibs(config android.Config) *snapshotMap {
+	return config.Once(vendorSnapshotHeaderLibsKey, func() interface{} {
+		return newSnapshotMap()
+	}).(*snapshotMap)
+}
+
+func vendorSnapshotSharedLibs(config android.Config) *snapshotMap {
+	return config.Once(vendorSnapshotSharedLibsKey, func() interface{} {
+		return newSnapshotMap()
+	}).(*snapshotMap)
+}
+
+func vendorSnapshotStaticLibs(config android.Config) *snapshotMap {
+	return config.Once(vendorSnapshotStaticLibsKey, func() interface{} {
+		return newSnapshotMap()
+	}).(*snapshotMap)
+}
+
+func vendorSnapshotBinaries(config android.Config) *snapshotMap {
+	return config.Once(vendorSnapshotBinariesKey, func() interface{} {
+		return newSnapshotMap()
+	}).(*snapshotMap)
+}
+
+func vendorSnapshotObjects(config android.Config) *snapshotMap {
+	return config.Once(vendorSnapshotObjectsKey, func() interface{} {
+		return newSnapshotMap()
+	}).(*snapshotMap)
+}
+
+type baseSnapshotDecoratorProperties struct {
+	// snapshot version.
+	Version string
+
+	// Target arch name of the snapshot (e.g. 'arm64' for variant 'aosp_arm64')
+	Target_arch string
+}
+
+// baseSnapshotDecorator provides common basic functions for all snapshot modules, such as snapshot
+// version, snapshot arch, etc. It also adds a special suffix to Soong module name, so it doesn't
+// collide with source modules. e.g. the following example module,
+//
+// vendor_snapshot_static {
+//     name: "libbase",
+//     arch: "arm64",
+//     version: 30,
+//     ...
+// }
+//
+// will be seen as "libbase.vendor_static.30.arm64" by Soong.
+type baseSnapshotDecorator struct {
+	baseProperties baseSnapshotDecoratorProperties
+	moduleSuffix   string
+}
+
+func (p *baseSnapshotDecorator) Name(name string) string {
+	return name + p.NameSuffix()
+}
+
+func (p *baseSnapshotDecorator) NameSuffix() string {
+	versionSuffix := p.version()
+	if p.arch() != "" {
+		versionSuffix += "." + p.arch()
+	}
+
+	return p.moduleSuffix + versionSuffix
+}
+
+func (p *baseSnapshotDecorator) version() string {
+	return p.baseProperties.Version
+}
+
+func (p *baseSnapshotDecorator) arch() string {
+	return p.baseProperties.Target_arch
+}
+
+func (p *baseSnapshotDecorator) isSnapshotPrebuilt() bool {
+	return true
+}
+
+// Call this with a module suffix after creating a snapshot module, such as
+// vendorSnapshotSharedSuffix, recoverySnapshotBinarySuffix, etc.
+func (p *baseSnapshotDecorator) init(m *Module, suffix string) {
+	p.moduleSuffix = suffix
+	m.AddProperties(&p.baseProperties)
+	android.AddLoadHook(m, func(ctx android.LoadHookContext) {
+		vendorSnapshotLoadHook(ctx, p)
+	})
+}
+
+// vendorSnapshotLoadHook disables snapshots if it's not BOARD_VNDK_VERSION.
+// As vendor snapshot is only for vendor, such modules won't be used at all.
+func vendorSnapshotLoadHook(ctx android.LoadHookContext, p *baseSnapshotDecorator) {
+	if p.version() != ctx.DeviceConfig().VndkVersion() {
+		ctx.Module().Disable()
+		return
+	}
+}
+
+//
+// Module definitions for snapshots of libraries (shared, static, header).
+//
+// Modules (vendor|recovery)_snapshot_(shared|static|header) are defined here. Shared libraries and
+// static libraries have their prebuilt library files (.so for shared, .a for static) as their src,
+// which can be installed or linked against. Also they export flags needed when linked, such as
+// include directories, c flags, sanitize dependency information, etc.
+//
+// These modules are auto-generated by development/vendor_snapshot/update.py.
+type snapshotLibraryProperties struct {
+	// Prebuilt file for each arch.
+	Src *string `android:"arch_variant"`
+
+	// list of directories that will be added to the include path (using -I).
+	Export_include_dirs []string `android:"arch_variant"`
+
+	// list of directories that will be added to the system path (using -isystem).
+	Export_system_include_dirs []string `android:"arch_variant"`
+
+	// list of flags that will be used for any module that links against this module.
+	Export_flags []string `android:"arch_variant"`
+
+	// Whether this prebuilt needs to depend on sanitize ubsan runtime or not.
+	Sanitize_ubsan_dep *bool `android:"arch_variant"`
+
+	// Whether this prebuilt needs to depend on sanitize minimal runtime or not.
+	Sanitize_minimal_dep *bool `android:"arch_variant"`
+}
+
+type snapshotSanitizer interface {
+	isSanitizerEnabled(t sanitizerType) bool
+	setSanitizerVariation(t sanitizerType, enabled bool)
+}
+
+type snapshotLibraryDecorator struct {
+	baseSnapshotDecorator
+	*libraryDecorator
+	properties          snapshotLibraryProperties
+	sanitizerProperties struct {
+		CfiEnabled bool `blueprint:"mutated"`
+
+		// Library flags for cfi variant.
+		Cfi snapshotLibraryProperties `android:"arch_variant"`
+	}
+	androidMkVendorSuffix bool
+}
+
+func (p *snapshotLibraryDecorator) linkerFlags(ctx ModuleContext, flags Flags) Flags {
+	p.libraryDecorator.libName = strings.TrimSuffix(ctx.ModuleName(), p.NameSuffix())
+	return p.libraryDecorator.linkerFlags(ctx, flags)
+}
+
+func (p *snapshotLibraryDecorator) matchesWithDevice(config android.DeviceConfig) bool {
+	arches := config.Arches()
+	if len(arches) == 0 || arches[0].ArchType.String() != p.arch() {
+		return false
+	}
+	if !p.header() && p.properties.Src == nil {
+		return false
+	}
+	return true
+}
+
+// cc modules' link functions are to link compiled objects into final binaries.
+// As snapshots are prebuilts, this just returns the prebuilt binary after doing things which are
+// done by normal library decorator, e.g. exporting flags.
+func (p *snapshotLibraryDecorator) link(ctx ModuleContext, flags Flags, deps PathDeps, objs Objects) android.Path {
+	m := ctx.Module().(*Module)
+	p.androidMkVendorSuffix = vendorSuffixModules(ctx.Config())[m.BaseModuleName()]
+
+	if p.header() {
+		return p.libraryDecorator.link(ctx, flags, deps, objs)
+	}
+
+	if p.sanitizerProperties.CfiEnabled {
+		p.properties = p.sanitizerProperties.Cfi
+	}
+
+	if !p.matchesWithDevice(ctx.DeviceConfig()) {
+		return nil
+	}
+
+	p.libraryDecorator.reexportDirs(android.PathsForModuleSrc(ctx, p.properties.Export_include_dirs)...)
+	p.libraryDecorator.reexportSystemDirs(android.PathsForModuleSrc(ctx, p.properties.Export_system_include_dirs)...)
+	p.libraryDecorator.reexportFlags(p.properties.Export_flags...)
+
+	in := android.PathForModuleSrc(ctx, *p.properties.Src)
+	p.unstrippedOutputFile = in
+
+	if p.shared() {
+		libName := in.Base()
+		builderFlags := flagsToBuilderFlags(flags)
+
+		// Optimize out relinking against shared libraries whose interface hasn't changed by
+		// depending on a table of contents file instead of the library itself.
+		tocFile := android.PathForModuleOut(ctx, libName+".toc")
+		p.tocFile = android.OptionalPathForPath(tocFile)
+		transformSharedObjectToToc(ctx, in, tocFile, builderFlags)
+
+		ctx.SetProvider(SharedLibraryInfoProvider, SharedLibraryInfo{
+			SharedLibrary:           in,
+			UnstrippedSharedLibrary: p.unstrippedOutputFile,
+
+			TableOfContents: p.tocFile,
+		})
+	}
+
+	if p.static() {
+		depSet := android.NewDepSetBuilder(android.TOPOLOGICAL).Direct(in).Build()
+		ctx.SetProvider(StaticLibraryInfoProvider, StaticLibraryInfo{
+			StaticLibrary: in,
+
+			TransitiveStaticLibrariesForOrdering: depSet,
+		})
+	}
+
+	p.libraryDecorator.flagExporter.setProvider(ctx)
+
+	return in
+}
+
+func (p *snapshotLibraryDecorator) install(ctx ModuleContext, file android.Path) {
+	if p.matchesWithDevice(ctx.DeviceConfig()) && (p.shared() || p.static()) {
+		p.baseInstaller.install(ctx, file)
+	}
+}
+
+func (p *snapshotLibraryDecorator) nativeCoverage() bool {
+	return false
+}
+
+func (p *snapshotLibraryDecorator) isSanitizerEnabled(t sanitizerType) bool {
+	switch t {
+	case cfi:
+		return p.sanitizerProperties.Cfi.Src != nil
+	default:
+		return false
+	}
+}
+
+func (p *snapshotLibraryDecorator) setSanitizerVariation(t sanitizerType, enabled bool) {
+	if !enabled {
+		return
+	}
+	switch t {
+	case cfi:
+		p.sanitizerProperties.CfiEnabled = true
+	default:
+		return
+	}
+}
+
+func snapshotLibraryFactory(suffix string) (*Module, *snapshotLibraryDecorator) {
+	module, library := NewLibrary(android.DeviceSupported)
+
+	module.stl = nil
+	module.sanitize = nil
+	library.disableStripping()
+
+	prebuilt := &snapshotLibraryDecorator{
+		libraryDecorator: library,
+	}
+
+	prebuilt.baseLinker.Properties.No_libcrt = BoolPtr(true)
+	prebuilt.baseLinker.Properties.Nocrt = BoolPtr(true)
+
+	// Prevent default system libs (libc, libm, and libdl) from being linked
+	if prebuilt.baseLinker.Properties.System_shared_libs == nil {
+		prebuilt.baseLinker.Properties.System_shared_libs = []string{}
+	}
+
+	module.compiler = nil
+	module.linker = prebuilt
+	module.installer = prebuilt
+
+	prebuilt.init(module, suffix)
+	module.AddProperties(
+		&prebuilt.properties,
+		&prebuilt.sanitizerProperties,
+	)
+
+	return module, prebuilt
+}
+
+// vendor_snapshot_shared is a special prebuilt shared library which is auto-generated by
+// development/vendor_snapshot/update.py. As a part of vendor snapshot, vendor_snapshot_shared
+// overrides the vendor variant of the cc shared library with the same name, if BOARD_VNDK_VERSION
+// is set.
+func VendorSnapshotSharedFactory() android.Module {
+	module, prebuilt := snapshotLibraryFactory(vendorSnapshotSharedSuffix)
+	prebuilt.libraryDecorator.BuildOnlyShared()
+	return module.Init()
+}
+
+// recovery_snapshot_shared is a special prebuilt shared library which is auto-generated by
+// development/vendor_snapshot/update.py. As a part of recovery snapshot, recovery_snapshot_shared
+// overrides the recovery variant of the cc shared library with the same name, if BOARD_VNDK_VERSION
+// is set.
+func RecoverySnapshotSharedFactory() android.Module {
+	module, prebuilt := snapshotLibraryFactory(recoverySnapshotSharedSuffix)
+	prebuilt.libraryDecorator.BuildOnlyShared()
+	return module.Init()
+}
+
+// vendor_snapshot_static is a special prebuilt static library which is auto-generated by
+// development/vendor_snapshot/update.py. As a part of vendor snapshot, vendor_snapshot_static
+// overrides the vendor variant of the cc static library with the same name, if BOARD_VNDK_VERSION
+// is set.
+func VendorSnapshotStaticFactory() android.Module {
+	module, prebuilt := snapshotLibraryFactory(vendorSnapshotStaticSuffix)
+	prebuilt.libraryDecorator.BuildOnlyStatic()
+	return module.Init()
+}
+
+// recovery_snapshot_static is a special prebuilt static library which is auto-generated by
+// development/vendor_snapshot/update.py. As a part of recovery snapshot, recovery_snapshot_static
+// overrides the recovery variant of the cc static library with the same name, if BOARD_VNDK_VERSION
+// is set.
+func RecoverySnapshotStaticFactory() android.Module {
+	module, prebuilt := snapshotLibraryFactory(recoverySnapshotStaticSuffix)
+	prebuilt.libraryDecorator.BuildOnlyStatic()
+	return module.Init()
+}
+
+// vendor_snapshot_header is a special header library which is auto-generated by
+// development/vendor_snapshot/update.py. As a part of vendor snapshot, vendor_snapshot_header
+// overrides the vendor variant of the cc header library with the same name, if BOARD_VNDK_VERSION
+// is set.
+func VendorSnapshotHeaderFactory() android.Module {
+	module, prebuilt := snapshotLibraryFactory(vendorSnapshotHeaderSuffix)
+	prebuilt.libraryDecorator.HeaderOnly()
+	return module.Init()
+}
+
+// recovery_snapshot_header is a special header library which is auto-generated by
+// development/vendor_snapshot/update.py. As a part of recovery snapshot, recovery_snapshot_header
+// overrides the recovery variant of the cc header library with the same name, if BOARD_VNDK_VERSION
+// is set.
+func RecoverySnapshotHeaderFactory() android.Module {
+	module, prebuilt := snapshotLibraryFactory(recoverySnapshotHeaderSuffix)
+	prebuilt.libraryDecorator.HeaderOnly()
+	return module.Init()
+}
+
+var _ snapshotSanitizer = (*snapshotLibraryDecorator)(nil)
+
+//
+// Module definitions for snapshots of executable binaries.
+//
+// Modules (vendor|recovery)_snapshot_binary are defined here. They have their prebuilt executable
+// binaries (e.g. toybox, sh) as their src, which can be installed.
+//
+// These modules are auto-generated by development/vendor_snapshot/update.py.
+type snapshotBinaryProperties struct {
+	// Prebuilt file for each arch.
+	Src *string `android:"arch_variant"`
+}
+
+type snapshotBinaryDecorator struct {
+	baseSnapshotDecorator
+	*binaryDecorator
+	properties            snapshotBinaryProperties
+	androidMkVendorSuffix bool
+}
+
+func (p *snapshotBinaryDecorator) matchesWithDevice(config android.DeviceConfig) bool {
+	if config.DeviceArch() != p.arch() {
+		return false
+	}
+	if p.properties.Src == nil {
+		return false
+	}
+	return true
+}
+
+// cc modules' link functions are to link compiled objects into final binaries.
+// As snapshots are prebuilts, this just returns the prebuilt binary
+func (p *snapshotBinaryDecorator) link(ctx ModuleContext, flags Flags, deps PathDeps, objs Objects) android.Path {
+	if !p.matchesWithDevice(ctx.DeviceConfig()) {
+		return nil
+	}
+
+	in := android.PathForModuleSrc(ctx, *p.properties.Src)
+	p.unstrippedOutputFile = in
+	binName := in.Base()
+
+	m := ctx.Module().(*Module)
+	p.androidMkVendorSuffix = vendorSuffixModules(ctx.Config())[m.BaseModuleName()]
+
+	// use cpExecutable to make it executable
+	outputFile := android.PathForModuleOut(ctx, binName)
+	ctx.Build(pctx, android.BuildParams{
+		Rule:        android.CpExecutable,
+		Description: "prebuilt",
+		Output:      outputFile,
+		Input:       in,
+	})
+
+	return outputFile
+}
+
+func (p *snapshotBinaryDecorator) nativeCoverage() bool {
+	return false
+}
+
+// vendor_snapshot_binary is a special prebuilt executable binary which is auto-generated by
+// development/vendor_snapshot/update.py. As a part of vendor snapshot, vendor_snapshot_binary
+// overrides the vendor variant of the cc binary with the same name, if BOARD_VNDK_VERSION is set.
+func VendorSnapshotBinaryFactory() android.Module {
+	return snapshotBinaryFactory(vendorSnapshotBinarySuffix)
+}
+
+// recovery_snapshot_binary is a special prebuilt executable binary which is auto-generated by
+// development/vendor_snapshot/update.py. As a part of recovery snapshot, recovery_snapshot_binary
+// overrides the recovery variant of the cc binary with the same name, if BOARD_VNDK_VERSION is set.
+func RecoverySnapshotBinaryFactory() android.Module {
+	return snapshotBinaryFactory(recoverySnapshotBinarySuffix)
+}
+
+func snapshotBinaryFactory(suffix string) android.Module {
+	module, binary := NewBinary(android.DeviceSupported)
+	binary.baseLinker.Properties.No_libcrt = BoolPtr(true)
+	binary.baseLinker.Properties.Nocrt = BoolPtr(true)
+
+	// Prevent default system libs (libc, libm, and libdl) from being linked
+	if binary.baseLinker.Properties.System_shared_libs == nil {
+		binary.baseLinker.Properties.System_shared_libs = []string{}
+	}
+
+	prebuilt := &snapshotBinaryDecorator{
+		binaryDecorator: binary,
+	}
+
+	module.compiler = nil
+	module.sanitize = nil
+	module.stl = nil
+	module.linker = prebuilt
+
+	prebuilt.init(module, suffix)
+	module.AddProperties(&prebuilt.properties)
+	return module.Init()
+}
+
+//
+// Module definitions for snapshots of object files (*.o).
+//
+// Modules (vendor|recovery)_snapshot_object are defined here. They have their prebuilt object
+// files (*.o) as their src.
+//
+// These modules are auto-generated by development/vendor_snapshot/update.py.
+type vendorSnapshotObjectProperties struct {
+	// Prebuilt file for each arch.
+	Src *string `android:"arch_variant"`
+}
+
+type snapshotObjectLinker struct {
+	baseSnapshotDecorator
+	objectLinker
+	properties            vendorSnapshotObjectProperties
+	androidMkVendorSuffix bool
+}
+
+func (p *snapshotObjectLinker) matchesWithDevice(config android.DeviceConfig) bool {
+	if config.DeviceArch() != p.arch() {
+		return false
+	}
+	if p.properties.Src == nil {
+		return false
+	}
+	return true
+}
+
+// cc modules' link functions are to link compiled objects into final binaries.
+// As snapshots are prebuilts, this just returns the prebuilt binary
+func (p *snapshotObjectLinker) link(ctx ModuleContext, flags Flags, deps PathDeps, objs Objects) android.Path {
+	if !p.matchesWithDevice(ctx.DeviceConfig()) {
+		return nil
+	}
+
+	m := ctx.Module().(*Module)
+	p.androidMkVendorSuffix = vendorSuffixModules(ctx.Config())[m.BaseModuleName()]
+
+	return android.PathForModuleSrc(ctx, *p.properties.Src)
+}
+
+func (p *snapshotObjectLinker) nativeCoverage() bool {
+	return false
+}
+
+// vendor_snapshot_object is a special prebuilt compiled object file which is auto-generated by
+// development/vendor_snapshot/update.py. As a part of vendor snapshot, vendor_snapshot_object
+// overrides the vendor variant of the cc object with the same name, if BOARD_VNDK_VERSION is set.
+func VendorSnapshotObjectFactory() android.Module {
+	module := newObject()
+
+	prebuilt := &snapshotObjectLinker{
+		objectLinker: objectLinker{
+			baseLinker: NewBaseLinker(nil),
+		},
+	}
+	module.linker = prebuilt
+
+	prebuilt.init(module, vendorSnapshotObjectSuffix)
+	module.AddProperties(&prebuilt.properties)
+	return module.Init()
+}
+
+// recovery_snapshot_object is a special prebuilt compiled object file which is auto-generated by
+// development/vendor_snapshot/update.py. As a part of recovery snapshot, recovery_snapshot_object
+// overrides the recovery variant of the cc object with the same name, if BOARD_VNDK_VERSION is set.
+func RecoverySnapshotObjectFactory() android.Module {
+	module := newObject()
+
+	prebuilt := &snapshotObjectLinker{
+		objectLinker: objectLinker{
+			baseLinker: NewBaseLinker(nil),
+		},
+	}
+	module.linker = prebuilt
+
+	prebuilt.init(module, recoverySnapshotObjectSuffix)
+	module.AddProperties(&prebuilt.properties)
+	return module.Init()
+}
+
+type snapshotInterface interface {
+	matchesWithDevice(config android.DeviceConfig) bool
+}
+
+var _ snapshotInterface = (*vndkPrebuiltLibraryDecorator)(nil)
+var _ snapshotInterface = (*snapshotLibraryDecorator)(nil)
+var _ snapshotInterface = (*snapshotBinaryDecorator)(nil)
+var _ snapshotInterface = (*snapshotObjectLinker)(nil)
+
+//
+// Mutators that helps vendor snapshot modules override source modules.
+//
+
+// VendorSnapshotMutator gathers all snapshots for vendor, and disable all snapshots which don't
+// match with device, e.g.
+//   - snapshot version is different with BOARD_VNDK_VERSION
+//   - snapshot arch is different with device's arch (e.g. arm vs x86)
+//
+// This also handles vndk_prebuilt_shared, except for they won't be disabled in any cases, given
+// that any versions of VNDK might be packed into vndk APEX.
+//
+// TODO(b/145966707): remove mutator and utilize android.Prebuilt to override source modules
+func VendorSnapshotMutator(ctx android.BottomUpMutatorContext) {
+	vndkVersion := ctx.DeviceConfig().VndkVersion()
+	// don't need snapshot if current
+	if vndkVersion == "current" || vndkVersion == "" {
+		return
+	}
+
+	module, ok := ctx.Module().(*Module)
+	if !ok || !module.Enabled() || module.VndkVersion() != vndkVersion {
+		return
+	}
+
+	if !module.isSnapshotPrebuilt() {
+		return
+	}
+
+	// isSnapshotPrebuilt ensures snapshotInterface
+	if !module.linker.(snapshotInterface).matchesWithDevice(ctx.DeviceConfig()) {
+		// Disable unnecessary snapshot module, but do not disable
+		// vndk_prebuilt_shared because they might be packed into vndk APEX
+		if !module.IsVndk() {
+			module.Disable()
+		}
+		return
+	}
+
+	var snapshotMap *snapshotMap
+
+	if lib, ok := module.linker.(libraryInterface); ok {
+		if lib.static() {
+			snapshotMap = vendorSnapshotStaticLibs(ctx.Config())
+		} else if lib.shared() {
+			snapshotMap = vendorSnapshotSharedLibs(ctx.Config())
+		} else {
+			// header
+			snapshotMap = vendorSnapshotHeaderLibs(ctx.Config())
+		}
+	} else if _, ok := module.linker.(*snapshotBinaryDecorator); ok {
+		snapshotMap = vendorSnapshotBinaries(ctx.Config())
+	} else if _, ok := module.linker.(*snapshotObjectLinker); ok {
+		snapshotMap = vendorSnapshotObjects(ctx.Config())
+	} else {
+		return
+	}
+
+	vendorSnapshotsLock.Lock()
+	defer vendorSnapshotsLock.Unlock()
+	snapshotMap.add(module.BaseModuleName(), ctx.Arch().ArchType, ctx.ModuleName())
+}
+
+// VendorSnapshotSourceMutator disables source modules which have corresponding snapshots.
+func VendorSnapshotSourceMutator(ctx android.BottomUpMutatorContext) {
+	if !ctx.Device() {
+		return
+	}
+
+	vndkVersion := ctx.DeviceConfig().VndkVersion()
+	// don't need snapshot if current
+	if vndkVersion == "current" || vndkVersion == "" {
+		return
+	}
+
+	module, ok := ctx.Module().(*Module)
+	if !ok {
+		return
+	}
+
+	// vendor suffix should be added to snapshots if the source module isn't vendor: true.
+	if !module.SocSpecific() {
+		// But we can't just check SocSpecific() since we already passed the image mutator.
+		// Check ramdisk and recovery to see if we are real "vendor: true" module.
+		ramdisk_available := module.InRamdisk() && !module.OnlyInRamdisk()
+		vendor_ramdisk_available := module.InVendorRamdisk() && !module.OnlyInVendorRamdisk()
+		recovery_available := module.InRecovery() && !module.OnlyInRecovery()
+
+		if !ramdisk_available && !recovery_available && !vendor_ramdisk_available {
+			vendorSnapshotsLock.Lock()
+			defer vendorSnapshotsLock.Unlock()
+
+			vendorSuffixModules(ctx.Config())[ctx.ModuleName()] = true
+		}
+	}
+
+	if module.isSnapshotPrebuilt() || module.VndkVersion() != ctx.DeviceConfig().VndkVersion() {
+		// only non-snapshot modules with BOARD_VNDK_VERSION
+		return
+	}
+
+	// .. and also filter out llndk library
+	if module.isLlndk(ctx.Config()) {
+		return
+	}
+
+	var snapshotMap *snapshotMap
+
+	if lib, ok := module.linker.(libraryInterface); ok {
+		if lib.static() {
+			snapshotMap = vendorSnapshotStaticLibs(ctx.Config())
+		} else if lib.shared() {
+			snapshotMap = vendorSnapshotSharedLibs(ctx.Config())
+		} else {
+			// header
+			snapshotMap = vendorSnapshotHeaderLibs(ctx.Config())
+		}
+	} else if module.binary() {
+		snapshotMap = vendorSnapshotBinaries(ctx.Config())
+	} else if module.object() {
+		snapshotMap = vendorSnapshotObjects(ctx.Config())
+	} else {
+		return
+	}
+
+	if _, ok := snapshotMap.get(ctx.ModuleName(), ctx.Arch().ArchType); !ok {
+		// Corresponding snapshot doesn't exist
+		return
+	}
+
+	// Disables source modules if corresponding snapshot exists.
+	if lib, ok := module.linker.(libraryInterface); ok && lib.buildStatic() && lib.buildShared() {
+		// But do not disable because the shared variant depends on the static variant.
+		module.SkipInstall()
+		module.Properties.HideFromMake = true
+	} else {
+		module.Disable()
+	}
+}
diff --git a/cc/snapshot_utils.go b/cc/snapshot_utils.go
index a3d52e6..e841a54 100644
--- a/cc/snapshot_utils.go
+++ b/cc/snapshot_utils.go
@@ -13,6 +13,8 @@
 // limitations under the License.
 package cc
 
+// This file contains utility types and functions for VNDK / vendor snapshot.
+
 import (
 	"android/soong/android"
 )
@@ -21,15 +23,24 @@
 	headerExts = []string{".h", ".hh", ".hpp", ".hxx", ".h++", ".inl", ".inc", ".ipp", ".h.generic"}
 )
 
+// snapshotLibraryInterface is an interface for libraries captured to VNDK / vendor snapshots.
 type snapshotLibraryInterface interface {
 	libraryInterface
+
+	// collectHeadersForSnapshot is called in GenerateAndroidBuildActions for snapshot aware
+	// modules (See isSnapshotAware below).
+	// This function should gather all headers needed for snapshot.
 	collectHeadersForSnapshot(ctx android.ModuleContext)
+
+	// snapshotHeaders should return collected headers by collectHeadersForSnapshot.
+	// Calling snapshotHeaders before collectHeadersForSnapshot is an error.
 	snapshotHeaders() android.Paths
 }
 
 var _ snapshotLibraryInterface = (*prebuiltLibraryLinker)(nil)
 var _ snapshotLibraryInterface = (*libraryDecorator)(nil)
 
+// snapshotMap is a helper wrapper to a map from base module name to snapshot module name.
 type snapshotMap struct {
 	snapshots map[string]string
 }
@@ -57,43 +68,14 @@
 	return snapshot, found
 }
 
-func isSnapshotAware(ctx android.ModuleContext, m *Module, apexInfo android.ApexInfo) bool {
-	if _, _, ok := isVndkSnapshotLibrary(ctx.DeviceConfig(), m, apexInfo); ok {
+// shouldCollectHeadersForSnapshot determines if the module is a possible candidate for snapshot.
+// If it's true, collectHeadersForSnapshot will be called in GenerateAndroidBuildActions.
+func shouldCollectHeadersForSnapshot(ctx android.ModuleContext, m *Module, apexInfo android.ApexInfo) bool {
+	if _, _, ok := isVndkSnapshotAware(ctx.DeviceConfig(), m, apexInfo); ok {
 		return ctx.Config().VndkSnapshotBuildArtifacts()
-	} else if isVendorSnapshotModule(m, isVendorProprietaryPath(ctx.ModuleDir()), apexInfo) ||
-		isRecoverySnapshotModule(m, isVendorProprietaryPath(ctx.ModuleDir()), apexInfo) {
+	} else if isVendorSnapshotAware(m, isVendorProprietaryPath(ctx.ModuleDir()), apexInfo) ||
+		isRecoverySnapshotAware(m, isRecoveryProprietaryPath(ctx.ModuleDir()), apexInfo) {
 		return true
 	}
 	return false
 }
-
-func copyFile(ctx android.SingletonContext, path android.Path, out string) android.OutputPath {
-	outPath := android.PathForOutput(ctx, out)
-	ctx.Build(pctx, android.BuildParams{
-		Rule:        android.Cp,
-		Input:       path,
-		Output:      outPath,
-		Description: "Cp " + out,
-		Args: map[string]string{
-			"cpFlags": "-f -L",
-		},
-	})
-	return outPath
-}
-
-func combineNotices(ctx android.SingletonContext, paths android.Paths, out string) android.OutputPath {
-	outPath := android.PathForOutput(ctx, out)
-	ctx.Build(pctx, android.BuildParams{
-		Rule:        android.Cat,
-		Inputs:      paths,
-		Output:      outPath,
-		Description: "combine notices for " + out,
-	})
-	return outPath
-}
-
-func writeStringToFile(ctx android.SingletonContext, content, out string) android.OutputPath {
-	outPath := android.PathForOutput(ctx, out)
-	android.WriteFileRule(ctx, outPath, content)
-	return outPath
-}
diff --git a/cc/util.go b/cc/util.go
index 40374bf..1220d84 100644
--- a/cc/util.go
+++ b/cc/util.go
@@ -125,3 +125,52 @@
 	return "mkdir -p " + dir + " && " +
 		"ln -sf " + target + " " + filepath.Join(dir, linkName)
 }
+
+func copyFileRule(ctx android.SingletonContext, path android.Path, out string) android.OutputPath {
+	outPath := android.PathForOutput(ctx, out)
+	ctx.Build(pctx, android.BuildParams{
+		Rule:        android.Cp,
+		Input:       path,
+		Output:      outPath,
+		Description: "copy " + path.String() + " -> " + out,
+		Args: map[string]string{
+			"cpFlags": "-f -L",
+		},
+	})
+	return outPath
+}
+
+func combineNoticesRule(ctx android.SingletonContext, paths android.Paths, out string) android.OutputPath {
+	outPath := android.PathForOutput(ctx, out)
+	ctx.Build(pctx, android.BuildParams{
+		Rule:        android.Cat,
+		Inputs:      paths,
+		Output:      outPath,
+		Description: "combine notices for " + out,
+	})
+	return outPath
+}
+
+func writeStringToFileRule(ctx android.SingletonContext, content, out string) android.OutputPath {
+	outPath := android.PathForOutput(ctx, out)
+	android.WriteFileRule(ctx, outPath, content)
+	return outPath
+}
+
+// Dump a map to a list file as:
+//
+// {key1} {value1}
+// {key2} {value2}
+// ...
+func installMapListFileRule(ctx android.SingletonContext, m map[string]string, path string) android.OutputPath {
+	var txtBuilder strings.Builder
+	for idx, k := range android.SortedStringKeys(m) {
+		if idx > 0 {
+			txtBuilder.WriteString("\n")
+		}
+		txtBuilder.WriteString(k)
+		txtBuilder.WriteString(" ")
+		txtBuilder.WriteString(m[k])
+	}
+	return writeStringToFileRule(ctx, txtBuilder.String(), path)
+}
diff --git a/cc/vendor_snapshot.go b/cc/vendor_snapshot.go
index 3ef0b62..25960ab 100644
--- a/cc/vendor_snapshot.go
+++ b/cc/vendor_snapshot.go
@@ -13,625 +13,27 @@
 // limitations under the License.
 package cc
 
+// This file contains singletons to capture vendor and recovery snapshot. They consist of prebuilt
+// modules under AOSP so older vendor and recovery can be built with a newer system in a single
+// source tree.
+
 import (
 	"encoding/json"
 	"path/filepath"
 	"sort"
 	"strings"
-	"sync"
 
 	"github.com/google/blueprint/proptools"
 
 	"android/soong/android"
 )
 
-// Defines the specifics of different images to which the snapshot process is
-// applicable, e.g., vendor, recovery, ramdisk.
-type image interface {
-	// Used to register callbacks with the build system.
-	init()
-
-	// Function that returns true if the module is included in this image.
-	// Using a function return instead of a value to prevent early
-	// evalution of a function that may be not be defined.
-	inImage(m *Module) func() bool
-
-	// Returns the value of the "available" property for a given module for
-	// and snapshot, e.g., "vendor_available", "recovery_available", etc.
-	// or nil if the property is not defined.
-	available(m *Module) *bool
-
-	// Returns true if a dir under source tree is an SoC-owned proprietary
-	// directory, such as device/, vendor/, etc.
-	//
-	// For a given snapshot (e.g., vendor, recovery, etc.) if
-	// isProprietaryPath(dir) returns true, then the module in dir will be
-	// built from sources.
-	isProprietaryPath(dir string) bool
-
-	// Whether to include VNDK in the snapshot for this image.
-	includeVndk() bool
-
-	// Whether a given module has been explicitly excluded from the
-	// snapshot, e.g., using the exclude_from_vendor_snapshot or
-	// exclude_from_recovery_snapshot properties.
-	excludeFromSnapshot(m *Module) bool
-}
-
-type vendorImage struct{}
-type recoveryImage struct{}
-
-func (vendorImage) init() {
-	android.RegisterSingletonType(
-		"vendor-snapshot", VendorSnapshotSingleton)
-	android.RegisterModuleType(
-		"vendor_snapshot_shared", VendorSnapshotSharedFactory)
-	android.RegisterModuleType(
-		"vendor_snapshot_static", VendorSnapshotStaticFactory)
-	android.RegisterModuleType(
-		"vendor_snapshot_header", VendorSnapshotHeaderFactory)
-	android.RegisterModuleType(
-		"vendor_snapshot_binary", VendorSnapshotBinaryFactory)
-	android.RegisterModuleType(
-		"vendor_snapshot_object", VendorSnapshotObjectFactory)
-}
-
-func (vendorImage) inImage(m *Module) func() bool {
-	return m.inVendor
-}
-
-func (vendorImage) available(m *Module) *bool {
-	return m.VendorProperties.Vendor_available
-}
-
-func (vendorImage) isProprietaryPath(dir string) bool {
-	return isVendorProprietaryPath(dir)
-}
-
-func (vendorImage) includeVndk() bool {
-	return true
-}
-
-func (vendorImage) excludeFromSnapshot(m *Module) bool {
-	return m.ExcludeFromVendorSnapshot()
-}
-
-func (recoveryImage) init() {
-	android.RegisterSingletonType(
-		"recovery-snapshot", RecoverySnapshotSingleton)
-	android.RegisterModuleType(
-		"recovery_snapshot_shared", RecoverySnapshotSharedFactory)
-	android.RegisterModuleType(
-		"recovery_snapshot_static", RecoverySnapshotStaticFactory)
-	android.RegisterModuleType(
-		"recovery_snapshot_header", RecoverySnapshotHeaderFactory)
-	android.RegisterModuleType(
-		"recovery_snapshot_binary", RecoverySnapshotBinaryFactory)
-	android.RegisterModuleType(
-		"recovery_snapshot_object", RecoverySnapshotObjectFactory)
-}
-
-func (recoveryImage) inImage(m *Module) func() bool {
-	return m.InRecovery
-}
-
-func (recoveryImage) available(m *Module) *bool {
-	return m.Properties.Recovery_available
-}
-
-func (recoveryImage) isProprietaryPath(dir string) bool {
-	return isRecoveryProprietaryPath(dir)
-}
-
-func (recoveryImage) includeVndk() bool {
-	return false
-}
-
-func (recoveryImage) excludeFromSnapshot(m *Module) bool {
-	return m.ExcludeFromRecoverySnapshot()
-}
-
-var vendorImageSingleton vendorImage
-var recoveryImageSingleton recoveryImage
-
-const (
-	vendorSnapshotHeaderSuffix = ".vendor_header."
-	vendorSnapshotSharedSuffix = ".vendor_shared."
-	vendorSnapshotStaticSuffix = ".vendor_static."
-	vendorSnapshotBinarySuffix = ".vendor_binary."
-	vendorSnapshotObjectSuffix = ".vendor_object."
-)
-
-const (
-	recoverySnapshotHeaderSuffix = ".recovery_header."
-	recoverySnapshotSharedSuffix = ".recovery_shared."
-	recoverySnapshotStaticSuffix = ".recovery_static."
-	recoverySnapshotBinarySuffix = ".recovery_binary."
-	recoverySnapshotObjectSuffix = ".recovery_object."
-)
-
-var (
-	vendorSnapshotsLock         sync.Mutex
-	vendorSuffixModulesKey      = android.NewOnceKey("vendorSuffixModules")
-	vendorSnapshotHeaderLibsKey = android.NewOnceKey("vendorSnapshotHeaderLibs")
-	vendorSnapshotStaticLibsKey = android.NewOnceKey("vendorSnapshotStaticLibs")
-	vendorSnapshotSharedLibsKey = android.NewOnceKey("vendorSnapshotSharedLibs")
-	vendorSnapshotBinariesKey   = android.NewOnceKey("vendorSnapshotBinaries")
-	vendorSnapshotObjectsKey    = android.NewOnceKey("vendorSnapshotObjects")
-)
-
-// vendor snapshot maps hold names of vendor snapshot modules per arch
-func vendorSuffixModules(config android.Config) map[string]bool {
-	return config.Once(vendorSuffixModulesKey, func() interface{} {
-		return make(map[string]bool)
-	}).(map[string]bool)
-}
-
-func vendorSnapshotHeaderLibs(config android.Config) *snapshotMap {
-	return config.Once(vendorSnapshotHeaderLibsKey, func() interface{} {
-		return newSnapshotMap()
-	}).(*snapshotMap)
-}
-
-func vendorSnapshotSharedLibs(config android.Config) *snapshotMap {
-	return config.Once(vendorSnapshotSharedLibsKey, func() interface{} {
-		return newSnapshotMap()
-	}).(*snapshotMap)
-}
-
-func vendorSnapshotStaticLibs(config android.Config) *snapshotMap {
-	return config.Once(vendorSnapshotStaticLibsKey, func() interface{} {
-		return newSnapshotMap()
-	}).(*snapshotMap)
-}
-
-func vendorSnapshotBinaries(config android.Config) *snapshotMap {
-	return config.Once(vendorSnapshotBinariesKey, func() interface{} {
-		return newSnapshotMap()
-	}).(*snapshotMap)
-}
-
-func vendorSnapshotObjects(config android.Config) *snapshotMap {
-	return config.Once(vendorSnapshotObjectsKey, func() interface{} {
-		return newSnapshotMap()
-	}).(*snapshotMap)
-}
-
-type vendorSnapshotBaseProperties struct {
-	// snapshot version.
-	Version string
-
-	// Target arch name of the snapshot (e.g. 'arm64' for variant 'aosp_arm64')
-	Target_arch string
-}
-
-// vendorSnapshotModuleBase provides common basic functions for all snapshot modules.
-type vendorSnapshotModuleBase struct {
-	baseProperties vendorSnapshotBaseProperties
-	moduleSuffix   string
-}
-
-func (p *vendorSnapshotModuleBase) Name(name string) string {
-	return name + p.NameSuffix()
-}
-
-func (p *vendorSnapshotModuleBase) NameSuffix() string {
-	versionSuffix := p.version()
-	if p.arch() != "" {
-		versionSuffix += "." + p.arch()
-	}
-
-	return p.moduleSuffix + versionSuffix
-}
-
-func (p *vendorSnapshotModuleBase) version() string {
-	return p.baseProperties.Version
-}
-
-func (p *vendorSnapshotModuleBase) arch() string {
-	return p.baseProperties.Target_arch
-}
-
-func (p *vendorSnapshotModuleBase) isSnapshotPrebuilt() bool {
-	return true
-}
-
-// Call this after creating a snapshot module with module suffix
-// such as vendorSnapshotSharedSuffix
-func (p *vendorSnapshotModuleBase) init(m *Module, suffix string) {
-	p.moduleSuffix = suffix
-	m.AddProperties(&p.baseProperties)
-	android.AddLoadHook(m, func(ctx android.LoadHookContext) {
-		vendorSnapshotLoadHook(ctx, p)
-	})
-}
-
-func vendorSnapshotLoadHook(ctx android.LoadHookContext, p *vendorSnapshotModuleBase) {
-	if p.version() != ctx.DeviceConfig().VndkVersion() {
-		ctx.Module().Disable()
-		return
-	}
-}
-
-type snapshotLibraryProperties struct {
-	// Prebuilt file for each arch.
-	Src *string `android:"arch_variant"`
-
-	// list of directories that will be added to the include path (using -I).
-	Export_include_dirs []string `android:"arch_variant"`
-
-	// list of directories that will be added to the system path (using -isystem).
-	Export_system_include_dirs []string `android:"arch_variant"`
-
-	// list of flags that will be used for any module that links against this module.
-	Export_flags []string `android:"arch_variant"`
-
-	// Whether this prebuilt needs to depend on sanitize ubsan runtime or not.
-	Sanitize_ubsan_dep *bool `android:"arch_variant"`
-
-	// Whether this prebuilt needs to depend on sanitize minimal runtime or not.
-	Sanitize_minimal_dep *bool `android:"arch_variant"`
-}
-
-type snapshotSanitizer interface {
-	isSanitizerEnabled(t sanitizerType) bool
-	setSanitizerVariation(t sanitizerType, enabled bool)
-}
-
-type snapshotLibraryDecorator struct {
-	vendorSnapshotModuleBase
-	*libraryDecorator
-	properties          snapshotLibraryProperties
-	sanitizerProperties struct {
-		CfiEnabled bool `blueprint:"mutated"`
-
-		// Library flags for cfi variant.
-		Cfi snapshotLibraryProperties `android:"arch_variant"`
-	}
-	androidMkVendorSuffix bool
-}
-
-func (p *snapshotLibraryDecorator) linkerFlags(ctx ModuleContext, flags Flags) Flags {
-	p.libraryDecorator.libName = strings.TrimSuffix(ctx.ModuleName(), p.NameSuffix())
-	return p.libraryDecorator.linkerFlags(ctx, flags)
-}
-
-func (p *snapshotLibraryDecorator) matchesWithDevice(config android.DeviceConfig) bool {
-	arches := config.Arches()
-	if len(arches) == 0 || arches[0].ArchType.String() != p.arch() {
-		return false
-	}
-	if !p.header() && p.properties.Src == nil {
-		return false
-	}
-	return true
-}
-
-func (p *snapshotLibraryDecorator) link(ctx ModuleContext,
-	flags Flags, deps PathDeps, objs Objects) android.Path {
-	m := ctx.Module().(*Module)
-	p.androidMkVendorSuffix = vendorSuffixModules(ctx.Config())[m.BaseModuleName()]
-
-	if p.header() {
-		return p.libraryDecorator.link(ctx, flags, deps, objs)
-	}
-
-	if p.sanitizerProperties.CfiEnabled {
-		p.properties = p.sanitizerProperties.Cfi
-	}
-
-	if !p.matchesWithDevice(ctx.DeviceConfig()) {
-		return nil
-	}
-
-	p.libraryDecorator.reexportDirs(android.PathsForModuleSrc(ctx, p.properties.Export_include_dirs)...)
-	p.libraryDecorator.reexportSystemDirs(android.PathsForModuleSrc(ctx, p.properties.Export_system_include_dirs)...)
-	p.libraryDecorator.reexportFlags(p.properties.Export_flags...)
-
-	in := android.PathForModuleSrc(ctx, *p.properties.Src)
-	p.unstrippedOutputFile = in
-
-	if p.shared() {
-		libName := in.Base()
-		builderFlags := flagsToBuilderFlags(flags)
-
-		// Optimize out relinking against shared libraries whose interface hasn't changed by
-		// depending on a table of contents file instead of the library itself.
-		tocFile := android.PathForModuleOut(ctx, libName+".toc")
-		p.tocFile = android.OptionalPathForPath(tocFile)
-		transformSharedObjectToToc(ctx, in, tocFile, builderFlags)
-
-		ctx.SetProvider(SharedLibraryInfoProvider, SharedLibraryInfo{
-			SharedLibrary:           in,
-			UnstrippedSharedLibrary: p.unstrippedOutputFile,
-
-			TableOfContents: p.tocFile,
-		})
-	}
-
-	if p.static() {
-		depSet := android.NewDepSetBuilder(android.TOPOLOGICAL).Direct(in).Build()
-		ctx.SetProvider(StaticLibraryInfoProvider, StaticLibraryInfo{
-			StaticLibrary: in,
-
-			TransitiveStaticLibrariesForOrdering: depSet,
-		})
-	}
-
-	p.libraryDecorator.flagExporter.setProvider(ctx)
-
-	return in
-}
-
-func (p *snapshotLibraryDecorator) install(ctx ModuleContext, file android.Path) {
-	if p.matchesWithDevice(ctx.DeviceConfig()) && (p.shared() || p.static()) {
-		p.baseInstaller.install(ctx, file)
-	}
-}
-
-func (p *snapshotLibraryDecorator) nativeCoverage() bool {
-	return false
-}
-
-func (p *snapshotLibraryDecorator) isSanitizerEnabled(t sanitizerType) bool {
-	switch t {
-	case cfi:
-		return p.sanitizerProperties.Cfi.Src != nil
-	default:
-		return false
-	}
-}
-
-func (p *snapshotLibraryDecorator) setSanitizerVariation(t sanitizerType, enabled bool) {
-	if !enabled {
-		return
-	}
-	switch t {
-	case cfi:
-		p.sanitizerProperties.CfiEnabled = true
-	default:
-		return
-	}
-}
-
-func snapshotLibrary(suffix string) (*Module, *snapshotLibraryDecorator) {
-	module, library := NewLibrary(android.DeviceSupported)
-
-	module.stl = nil
-	module.sanitize = nil
-	library.disableStripping()
-
-	prebuilt := &snapshotLibraryDecorator{
-		libraryDecorator: library,
-	}
-
-	prebuilt.baseLinker.Properties.No_libcrt = BoolPtr(true)
-	prebuilt.baseLinker.Properties.Nocrt = BoolPtr(true)
-
-	// Prevent default system libs (libc, libm, and libdl) from being linked
-	if prebuilt.baseLinker.Properties.System_shared_libs == nil {
-		prebuilt.baseLinker.Properties.System_shared_libs = []string{}
-	}
-
-	module.compiler = nil
-	module.linker = prebuilt
-	module.installer = prebuilt
-
-	prebuilt.init(module, suffix)
-	module.AddProperties(
-		&prebuilt.properties,
-		&prebuilt.sanitizerProperties,
-	)
-
-	return module, prebuilt
-}
-
-func VendorSnapshotSharedFactory() android.Module {
-	module, prebuilt := snapshotLibrary(vendorSnapshotSharedSuffix)
-	prebuilt.libraryDecorator.BuildOnlyShared()
-	return module.Init()
-}
-
-func RecoverySnapshotSharedFactory() android.Module {
-	module, prebuilt := snapshotLibrary(recoverySnapshotSharedSuffix)
-	prebuilt.libraryDecorator.BuildOnlyShared()
-	return module.Init()
-}
-
-func VendorSnapshotStaticFactory() android.Module {
-	module, prebuilt := snapshotLibrary(vendorSnapshotStaticSuffix)
-	prebuilt.libraryDecorator.BuildOnlyStatic()
-	return module.Init()
-}
-
-func RecoverySnapshotStaticFactory() android.Module {
-	module, prebuilt := snapshotLibrary(recoverySnapshotStaticSuffix)
-	prebuilt.libraryDecorator.BuildOnlyStatic()
-	return module.Init()
-}
-
-func VendorSnapshotHeaderFactory() android.Module {
-	module, prebuilt := snapshotLibrary(vendorSnapshotHeaderSuffix)
-	prebuilt.libraryDecorator.HeaderOnly()
-	return module.Init()
-}
-
-func RecoverySnapshotHeaderFactory() android.Module {
-	module, prebuilt := snapshotLibrary(recoverySnapshotHeaderSuffix)
-	prebuilt.libraryDecorator.HeaderOnly()
-	return module.Init()
-}
-
-var _ snapshotSanitizer = (*snapshotLibraryDecorator)(nil)
-
-type snapshotBinaryProperties struct {
-	// Prebuilt file for each arch.
-	Src *string `android:"arch_variant"`
-}
-
-type snapshotBinaryDecorator struct {
-	vendorSnapshotModuleBase
-	*binaryDecorator
-	properties            snapshotBinaryProperties
-	androidMkVendorSuffix bool
-}
-
-func (p *snapshotBinaryDecorator) matchesWithDevice(config android.DeviceConfig) bool {
-	if config.DeviceArch() != p.arch() {
-		return false
-	}
-	if p.properties.Src == nil {
-		return false
-	}
-	return true
-}
-
-func (p *snapshotBinaryDecorator) link(ctx ModuleContext,
-	flags Flags, deps PathDeps, objs Objects) android.Path {
-	if !p.matchesWithDevice(ctx.DeviceConfig()) {
-		return nil
-	}
-
-	in := android.PathForModuleSrc(ctx, *p.properties.Src)
-	stripFlags := flagsToStripFlags(flags)
-	p.unstrippedOutputFile = in
-	binName := in.Base()
-	if p.stripper.NeedsStrip(ctx) {
-		stripped := android.PathForModuleOut(ctx, "stripped", binName)
-		p.stripper.StripExecutableOrSharedLib(ctx, in, stripped, stripFlags)
-		in = stripped
-	}
-
-	m := ctx.Module().(*Module)
-	p.androidMkVendorSuffix = vendorSuffixModules(ctx.Config())[m.BaseModuleName()]
-
-	// use cpExecutable to make it executable
-	outputFile := android.PathForModuleOut(ctx, binName)
-	ctx.Build(pctx, android.BuildParams{
-		Rule:        android.CpExecutable,
-		Description: "prebuilt",
-		Output:      outputFile,
-		Input:       in,
-	})
-
-	return outputFile
-}
-
-func (p *snapshotBinaryDecorator) nativeCoverage() bool {
-	return false
-}
-
-func VendorSnapshotBinaryFactory() android.Module {
-	return snapshotBinaryFactory(vendorSnapshotBinarySuffix)
-}
-
-func RecoverySnapshotBinaryFactory() android.Module {
-	return snapshotBinaryFactory(recoverySnapshotBinarySuffix)
-}
-
-func snapshotBinaryFactory(suffix string) android.Module {
-	module, binary := NewBinary(android.DeviceSupported)
-	binary.baseLinker.Properties.No_libcrt = BoolPtr(true)
-	binary.baseLinker.Properties.Nocrt = BoolPtr(true)
-
-	// Prevent default system libs (libc, libm, and libdl) from being linked
-	if binary.baseLinker.Properties.System_shared_libs == nil {
-		binary.baseLinker.Properties.System_shared_libs = []string{}
-	}
-
-	prebuilt := &snapshotBinaryDecorator{
-		binaryDecorator: binary,
-	}
-
-	module.compiler = nil
-	module.sanitize = nil
-	module.stl = nil
-	module.linker = prebuilt
-
-	prebuilt.init(module, suffix)
-	module.AddProperties(&prebuilt.properties)
-	return module.Init()
-}
-
-type vendorSnapshotObjectProperties struct {
-	// Prebuilt file for each arch.
-	Src *string `android:"arch_variant"`
-}
-
-type snapshotObjectLinker struct {
-	vendorSnapshotModuleBase
-	objectLinker
-	properties            vendorSnapshotObjectProperties
-	androidMkVendorSuffix bool
-}
-
-func (p *snapshotObjectLinker) matchesWithDevice(config android.DeviceConfig) bool {
-	if config.DeviceArch() != p.arch() {
-		return false
-	}
-	if p.properties.Src == nil {
-		return false
-	}
-	return true
-}
-
-func (p *snapshotObjectLinker) link(ctx ModuleContext,
-	flags Flags, deps PathDeps, objs Objects) android.Path {
-	if !p.matchesWithDevice(ctx.DeviceConfig()) {
-		return nil
-	}
-
-	m := ctx.Module().(*Module)
-	p.androidMkVendorSuffix = vendorSuffixModules(ctx.Config())[m.BaseModuleName()]
-
-	return android.PathForModuleSrc(ctx, *p.properties.Src)
-}
-
-func (p *snapshotObjectLinker) nativeCoverage() bool {
-	return false
-}
-
-func VendorSnapshotObjectFactory() android.Module {
-	module := newObject()
-
-	prebuilt := &snapshotObjectLinker{
-		objectLinker: objectLinker{
-			baseLinker: NewBaseLinker(nil),
-		},
-	}
-	module.linker = prebuilt
-
-	prebuilt.init(module, vendorSnapshotObjectSuffix)
-	module.AddProperties(&prebuilt.properties)
-	return module.Init()
-}
-
-func RecoverySnapshotObjectFactory() android.Module {
-	module := newObject()
-
-	prebuilt := &snapshotObjectLinker{
-		objectLinker: objectLinker{
-			baseLinker: NewBaseLinker(nil),
-		},
-	}
-	module.linker = prebuilt
-
-	prebuilt.init(module, recoverySnapshotObjectSuffix)
-	module.AddProperties(&prebuilt.properties)
-	return module.Init()
-}
-
-func init() {
-	vendorImageSingleton.init()
-	recoveryImageSingleton.init()
-}
-
 var vendorSnapshotSingleton = snapshotSingleton{
 	"vendor",
 	"SOONG_VENDOR_SNAPSHOT_ZIP",
 	android.OptionalPath{},
 	true,
-	vendorImageSingleton,
+	vendorSnapshotImageSingleton,
 }
 
 var recoverySnapshotSingleton = snapshotSingleton{
@@ -639,7 +41,7 @@
 	"SOONG_RECOVERY_SNAPSHOT_ZIP",
 	android.OptionalPath{},
 	false,
-	recoveryImageSingleton,
+	recoverySnapshotImageSingleton,
 }
 
 func VendorSnapshotSingleton() android.Singleton {
@@ -667,13 +69,12 @@
 	// Implementation of the image interface specific to the image
 	// associated with this snapshot (e.g., specific to the vendor image,
 	// recovery image, etc.).
-	image image
+	image snapshotImage
 }
 
 var (
 	// Modules under following directories are ignored. They are OEM's and vendor's
 	// proprietary modules(device/, kernel/, vendor/, and hardware/).
-	// TODO(b/65377115): Clean up these with more maintainable way
 	vendorProprietaryDirs = []string{
 		"device",
 		"kernel",
@@ -683,7 +84,6 @@
 
 	// Modules under following directories are ignored. They are OEM's and vendor's
 	// proprietary modules(device/, kernel/, vendor/, and hardware/).
-	// TODO(b/65377115): Clean up these with more maintainable way
 	recoveryProprietaryDirs = []string{
 		"bootable/recovery",
 		"device",
@@ -694,7 +94,6 @@
 
 	// Modules under following directories are included as they are in AOSP,
 	// although hardware/ and kernel/ are normally for vendor's own.
-	// TODO(b/65377115): Clean up these with more maintainable way
 	aospDirsUnderProprietary = []string{
 		"kernel/configs",
 		"kernel/prebuilts",
@@ -738,10 +137,8 @@
 }
 
 func isVendorProprietaryModule(ctx android.BaseModuleContext) bool {
-
 	// Any module in a vendor proprietary path is a vendor proprietary
 	// module.
-
 	if isVendorProprietaryPath(ctx.ModuleDir()) {
 		return true
 	}
@@ -750,7 +147,6 @@
 	// still be a vendor proprietary module. This happens for cc modules
 	// that are excluded from the vendor snapshot, and it means that the
 	// vendor has assumed control of the framework-provided module.
-
 	if c, ok := ctx.Module().(*Module); ok {
 		if c.ExcludeFromVendorSnapshot() {
 			return true
@@ -766,15 +162,21 @@
 // AOSP. They are not guaranteed to be compatible with older vendor images. (e.g. might
 // depend on newer VNDK) So they are captured as vendor snapshot To build older vendor
 // image and newer system image altogether.
-func isVendorSnapshotModule(m *Module, inVendorProprietaryPath bool, apexInfo android.ApexInfo) bool {
-	return isSnapshotModule(m, inVendorProprietaryPath, apexInfo, vendorImageSingleton)
+func isVendorSnapshotAware(m *Module, inVendorProprietaryPath bool, apexInfo android.ApexInfo) bool {
+	return isSnapshotAware(m, inVendorProprietaryPath, apexInfo, vendorSnapshotImageSingleton)
 }
 
-func isRecoverySnapshotModule(m *Module, inRecoveryProprietaryPath bool, apexInfo android.ApexInfo) bool {
-	return isSnapshotModule(m, inRecoveryProprietaryPath, apexInfo, recoveryImageSingleton)
+// Determine if a module is going to be included in recovery snapshot or not.
+//
+// Targets of recovery snapshot are "recovery: true" or "recovery_available: true"
+// modules in AOSP. They are not guaranteed to be compatible with older recovery images.
+// So they are captured as recovery snapshot To build older recovery image.
+func isRecoverySnapshotAware(m *Module, inRecoveryProprietaryPath bool, apexInfo android.ApexInfo) bool {
+	return isSnapshotAware(m, inRecoveryProprietaryPath, apexInfo, recoverySnapshotImageSingleton)
 }
 
-func isSnapshotModule(m *Module, inProprietaryPath bool, apexInfo android.ApexInfo, image image) bool {
+// Determines if the module is a candidate for snapshot.
+func isSnapshotAware(m *Module, inProprietaryPath bool, apexInfo android.ApexInfo, image snapshotImage) bool {
 	if !m.Enabled() || m.Properties.HideFromMake {
 		return false
 	}
@@ -799,7 +201,7 @@
 	if m.Target().NativeBridge == android.NativeBridgeEnabled {
 		return false
 	}
-	// the module must be installed in /vendor
+	// the module must be installed in target image
 	if !apexInfo.IsForPlatform() || m.isSnapshotPrebuilt() || !image.inImage(m)() {
 		return false
 	}
@@ -817,7 +219,6 @@
 
 	// Libraries
 	if l, ok := m.linker.(snapshotLibraryInterface); ok {
-		// TODO(b/65377115): add full support for sanitizer
 		if m.sanitize != nil {
 			// scs and hwasan export both sanitized and unsanitized variants for static and header
 			// Always use unsanitized variants of them.
@@ -827,6 +228,8 @@
 				}
 			}
 			// cfi also exports both variants. But for static, we capture both.
+			// This is because cfi static libraries can't be linked from non-cfi modules,
+			// and vice versa. This isn't the case for scs and hwasan sanitizers.
 			if !l.static() && !l.shared() && m.sanitize.isSanitizerEnabled(cfi) {
 				return false
 			}
@@ -856,6 +259,33 @@
 	return false
 }
 
+// This is to be saved as .json files, which is for development/vendor_snapshot/update.py.
+// These flags become Android.bp snapshot module properties.
+type snapshotJsonFlags struct {
+	ModuleName          string `json:",omitempty"`
+	RelativeInstallPath string `json:",omitempty"`
+
+	// library flags
+	ExportedDirs       []string `json:",omitempty"`
+	ExportedSystemDirs []string `json:",omitempty"`
+	ExportedFlags      []string `json:",omitempty"`
+	Sanitize           string   `json:",omitempty"`
+	SanitizeMinimalDep bool     `json:",omitempty"`
+	SanitizeUbsanDep   bool     `json:",omitempty"`
+
+	// binary flags
+	Symlinks []string `json:",omitempty"`
+
+	// dependencies
+	SharedLibs  []string `json:",omitempty"`
+	RuntimeLibs []string `json:",omitempty"`
+	Required    []string `json:",omitempty"`
+
+	// extra config files
+	InitRc         []string `json:",omitempty"`
+	VintfFragments []string `json:",omitempty"`
+}
+
 func (c *snapshotSingleton) GenerateBuildActions(ctx android.SingletonContext) {
 	// BOARD_VNDK_VERSION must be set to 'current' in order to generate a vendor snapshot.
 	if ctx.DeviceConfig().VndkVersion() != "current" {
@@ -909,6 +339,8 @@
 
 	var headers android.Paths
 
+	// installSnapshot function copies prebuilt file (.so, .a, or executable) and json flag file.
+	// For executables, init_rc and vintf_fragments files are also copied.
 	installSnapshot := func(m *Module) android.Paths {
 		targetArch := "arch-" + m.Target().Arch.ArchType.String()
 		if m.Target().Arch.ArchVariant != "" {
@@ -917,30 +349,7 @@
 
 		var ret android.Paths
 
-		prop := struct {
-			ModuleName          string `json:",omitempty"`
-			RelativeInstallPath string `json:",omitempty"`
-
-			// library flags
-			ExportedDirs       []string `json:",omitempty"`
-			ExportedSystemDirs []string `json:",omitempty"`
-			ExportedFlags      []string `json:",omitempty"`
-			Sanitize           string   `json:",omitempty"`
-			SanitizeMinimalDep bool     `json:",omitempty"`
-			SanitizeUbsanDep   bool     `json:",omitempty"`
-
-			// binary flags
-			Symlinks []string `json:",omitempty"`
-
-			// dependencies
-			SharedLibs  []string `json:",omitempty"`
-			RuntimeLibs []string `json:",omitempty"`
-			Required    []string `json:",omitempty"`
-
-			// extra config files
-			InitRc         []string `json:",omitempty"`
-			VintfFragments []string `json:",omitempty"`
-		}{}
+		prop := snapshotJsonFlags{}
 
 		// Common properties among snapshots.
 		prop.ModuleName = ctx.ModuleName(m)
@@ -968,7 +377,7 @@
 			out := filepath.Join(configsDir, path.Base())
 			if !installedConfigs[out] {
 				installedConfigs[out] = true
-				ret = append(ret, copyFile(ctx, path, out))
+				ret = append(ret, copyFileRule(ctx, path, out))
 			}
 		}
 
@@ -1019,7 +428,7 @@
 					prop.ModuleName += ".cfi"
 				}
 				snapshotLibOut := filepath.Join(snapshotArchDir, targetArch, libType, stem)
-				ret = append(ret, copyFile(ctx, libPath, snapshotLibOut))
+				ret = append(ret, copyFileRule(ctx, libPath, snapshotLibOut))
 			} else {
 				stem = ctx.ModuleName(m)
 			}
@@ -1033,7 +442,7 @@
 			// install bin
 			binPath := m.outputFile.Path()
 			snapshotBinOut := filepath.Join(snapshotArchDir, targetArch, "binary", binPath.Base())
-			ret = append(ret, copyFile(ctx, binPath, snapshotBinOut))
+			ret = append(ret, copyFileRule(ctx, binPath, snapshotBinOut))
 			propOut = snapshotBinOut + ".json"
 		} else if m.object() {
 			// object files aren't installed to the device, so their names can conflict.
@@ -1041,7 +450,7 @@
 			objPath := m.outputFile.Path()
 			snapshotObjOut := filepath.Join(snapshotArchDir, targetArch, "object",
 				ctx.ModuleName(m)+filepath.Ext(objPath.Base()))
-			ret = append(ret, copyFile(ctx, objPath, snapshotObjOut))
+			ret = append(ret, copyFileRule(ctx, objPath, snapshotObjOut))
 			propOut = snapshotObjOut + ".json"
 		} else {
 			ctx.Errorf("unknown module %q in vendor snapshot", m.String())
@@ -1053,7 +462,7 @@
 			ctx.Errorf("json marshal to %q failed: %#v", propOut, err)
 			return nil
 		}
-		ret = append(ret, writeStringToFile(ctx, string(j), propOut))
+		ret = append(ret, writeStringToFileRule(ctx, string(j), propOut))
 
 		return ret
 	}
@@ -1088,11 +497,14 @@
 			}
 		}
 
-		if !isSnapshotModule(m, inProprietaryPath, apexInfo, c.image) {
+		if !isSnapshotAware(m, inProprietaryPath, apexInfo, c.image) {
 			return
 		}
 
+		// installSnapshot installs prebuilts and json flag files
 		snapshotOutputs = append(snapshotOutputs, installSnapshot(m)...)
+
+		// just gather headers and notice files here, because they are to be deduplicated
 		if l, ok := m.linker.(snapshotLibraryInterface); ok {
 			headers = append(headers, l.snapshotHeaders()...)
 		}
@@ -1103,7 +515,7 @@
 			// skip already copied notice file
 			if !installedNotices[noticeOut] {
 				installedNotices[noticeOut] = true
-				snapshotOutputs = append(snapshotOutputs, combineNotices(
+				snapshotOutputs = append(snapshotOutputs, combineNoticesRule(
 					ctx, m.NoticeFiles(), noticeOut))
 			}
 		}
@@ -1111,7 +523,7 @@
 
 	// install all headers after removing duplicates
 	for _, header := range android.FirstUniquePaths(headers) {
-		snapshotOutputs = append(snapshotOutputs, copyFile(
+		snapshotOutputs = append(snapshotOutputs, copyFileRule(
 			ctx, header, filepath.Join(includeDir, header.String())))
 	}
 
@@ -1155,141 +567,3 @@
 		c.makeVar,
 		c.snapshotZipFile.String())
 }
-
-type snapshotInterface interface {
-	matchesWithDevice(config android.DeviceConfig) bool
-}
-
-var _ snapshotInterface = (*vndkPrebuiltLibraryDecorator)(nil)
-var _ snapshotInterface = (*snapshotLibraryDecorator)(nil)
-var _ snapshotInterface = (*snapshotBinaryDecorator)(nil)
-var _ snapshotInterface = (*snapshotObjectLinker)(nil)
-
-// gathers all snapshot modules for vendor, and disable unnecessary snapshots
-// TODO(b/145966707): remove mutator and utilize android.Prebuilt to override source modules
-func VendorSnapshotMutator(ctx android.BottomUpMutatorContext) {
-	vndkVersion := ctx.DeviceConfig().VndkVersion()
-	// don't need snapshot if current
-	if vndkVersion == "current" || vndkVersion == "" {
-		return
-	}
-
-	module, ok := ctx.Module().(*Module)
-	if !ok || !module.Enabled() || module.VndkVersion() != vndkVersion {
-		return
-	}
-
-	if !module.isSnapshotPrebuilt() {
-		return
-	}
-
-	// isSnapshotPrebuilt ensures snapshotInterface
-	if !module.linker.(snapshotInterface).matchesWithDevice(ctx.DeviceConfig()) {
-		// Disable unnecessary snapshot module, but do not disable
-		// vndk_prebuilt_shared because they might be packed into vndk APEX
-		if !module.IsVndk() {
-			module.Disable()
-		}
-		return
-	}
-
-	var snapshotMap *snapshotMap
-
-	if lib, ok := module.linker.(libraryInterface); ok {
-		if lib.static() {
-			snapshotMap = vendorSnapshotStaticLibs(ctx.Config())
-		} else if lib.shared() {
-			snapshotMap = vendorSnapshotSharedLibs(ctx.Config())
-		} else {
-			// header
-			snapshotMap = vendorSnapshotHeaderLibs(ctx.Config())
-		}
-	} else if _, ok := module.linker.(*snapshotBinaryDecorator); ok {
-		snapshotMap = vendorSnapshotBinaries(ctx.Config())
-	} else if _, ok := module.linker.(*snapshotObjectLinker); ok {
-		snapshotMap = vendorSnapshotObjects(ctx.Config())
-	} else {
-		return
-	}
-
-	vendorSnapshotsLock.Lock()
-	defer vendorSnapshotsLock.Unlock()
-	snapshotMap.add(module.BaseModuleName(), ctx.Arch().ArchType, ctx.ModuleName())
-}
-
-// Disables source modules which have snapshots
-func VendorSnapshotSourceMutator(ctx android.BottomUpMutatorContext) {
-	if !ctx.Device() {
-		return
-	}
-
-	vndkVersion := ctx.DeviceConfig().VndkVersion()
-	// don't need snapshot if current
-	if vndkVersion == "current" || vndkVersion == "" {
-		return
-	}
-
-	module, ok := ctx.Module().(*Module)
-	if !ok {
-		return
-	}
-
-	// vendor suffix should be added to snapshots if the source module isn't vendor: true.
-	if !module.SocSpecific() {
-		// But we can't just check SocSpecific() since we already passed the image mutator.
-		// Check ramdisk and recovery to see if we are real "vendor: true" module.
-		ramdisk_available := module.InRamdisk() && !module.OnlyInRamdisk()
-		vendor_ramdisk_available := module.InVendorRamdisk() && !module.OnlyInVendorRamdisk()
-		recovery_available := module.InRecovery() && !module.OnlyInRecovery()
-
-		if !ramdisk_available && !recovery_available && !vendor_ramdisk_available {
-			vendorSnapshotsLock.Lock()
-			defer vendorSnapshotsLock.Unlock()
-
-			vendorSuffixModules(ctx.Config())[ctx.ModuleName()] = true
-		}
-	}
-
-	if module.isSnapshotPrebuilt() || module.VndkVersion() != ctx.DeviceConfig().VndkVersion() {
-		// only non-snapshot modules with BOARD_VNDK_VERSION
-		return
-	}
-
-	// .. and also filter out llndk library
-	if module.isLlndk(ctx.Config()) {
-		return
-	}
-
-	var snapshotMap *snapshotMap
-
-	if lib, ok := module.linker.(libraryInterface); ok {
-		if lib.static() {
-			snapshotMap = vendorSnapshotStaticLibs(ctx.Config())
-		} else if lib.shared() {
-			snapshotMap = vendorSnapshotSharedLibs(ctx.Config())
-		} else {
-			// header
-			snapshotMap = vendorSnapshotHeaderLibs(ctx.Config())
-		}
-	} else if module.binary() {
-		snapshotMap = vendorSnapshotBinaries(ctx.Config())
-	} else if module.object() {
-		snapshotMap = vendorSnapshotObjects(ctx.Config())
-	} else {
-		return
-	}
-
-	if _, ok := snapshotMap.get(ctx.ModuleName(), ctx.Arch().ArchType); !ok {
-		// Corresponding snapshot doesn't exist
-		return
-	}
-
-	// Disables source modules if corresponding snapshot exists.
-	if lib, ok := module.linker.(libraryInterface); ok && lib.buildStatic() && lib.buildShared() {
-		// But do not disable because the shared variant depends on the static variant.
-		module.SkipInstall()
-		module.Properties.HideFromMake = true
-	} else {
-		module.Disable()
-	}
-}
diff --git a/cc/vndk.go b/cc/vndk.go
index d57cdf7..eca1cdf 100644
--- a/cc/vndk.go
+++ b/cc/vndk.go
@@ -533,7 +533,7 @@
 	vndkSnapshotZipFile android.OptionalPath
 }
 
-func isVndkSnapshotLibrary(config android.DeviceConfig, m *Module,
+func isVndkSnapshotAware(config android.DeviceConfig, m *Module,
 	apexInfo android.ApexInfo) (i snapshotLibraryInterface, vndkType string, isVndkSnapshotLib bool) {
 
 	if m.Target().NativeBridge == android.NativeBridgeEnabled {
@@ -622,6 +622,9 @@
 
 	var headers android.Paths
 
+	// installVndkSnapshotLib copies built .so file from the module.
+	// Also, if the build artifacts is on, write a json file which contains all exported flags
+	// with FlagExporterInfo.
 	installVndkSnapshotLib := func(m *Module, vndkType string) (android.Paths, bool) {
 		var ret android.Paths
 
@@ -632,7 +635,7 @@
 
 		libPath := m.outputFile.Path()
 		snapshotLibOut := filepath.Join(snapshotArchDir, targetArch, "shared", vndkType, libPath.Base())
-		ret = append(ret, copyFile(ctx, libPath, snapshotLibOut))
+		ret = append(ret, copyFileRule(ctx, libPath, snapshotLibOut))
 
 		if ctx.Config().VndkSnapshotBuildArtifacts() {
 			prop := struct {
@@ -654,7 +657,7 @@
 				ctx.Errorf("json marshal to %q failed: %#v", propOut, err)
 				return nil, false
 			}
-			ret = append(ret, writeStringToFile(ctx, string(j), propOut))
+			ret = append(ret, writeStringToFileRule(ctx, string(j), propOut))
 		}
 		return ret, true
 	}
@@ -667,11 +670,21 @@
 
 		apexInfo := ctx.ModuleProvider(module, android.ApexInfoProvider).(android.ApexInfo)
 
-		l, vndkType, ok := isVndkSnapshotLibrary(ctx.DeviceConfig(), m, apexInfo)
+		l, vndkType, ok := isVndkSnapshotAware(ctx.DeviceConfig(), m, apexInfo)
 		if !ok {
 			return
 		}
 
+		// For all snapshot candidates, the followings are captured.
+		//   - .so files
+		//   - notice files
+		//
+		// The followings are also captured if VNDK_SNAPSHOT_BUILD_ARTIFACTS.
+		//   - .json files containing exported flags
+		//   - exported headers from collectHeadersForSnapshot()
+		//
+		// Headers are deduplicated after visiting all modules.
+
 		// install .so files for appropriate modules.
 		// Also install .json files if VNDK_SNAPSHOT_BUILD_ARTIFACTS
 		libs, ok := installVndkSnapshotLib(m, vndkType)
@@ -690,7 +703,7 @@
 			// skip already copied notice file
 			if _, ok := noticeBuilt[noticeName]; !ok {
 				noticeBuilt[noticeName] = true
-				snapshotOutputs = append(snapshotOutputs, combineNotices(
+				snapshotOutputs = append(snapshotOutputs, combineNoticesRule(
 					ctx, m.NoticeFiles(), filepath.Join(noticeDir, noticeName)))
 			}
 		}
@@ -702,7 +715,7 @@
 
 	// install all headers after removing duplicates
 	for _, header := range android.FirstUniquePaths(headers) {
-		snapshotOutputs = append(snapshotOutputs, copyFile(
+		snapshotOutputs = append(snapshotOutputs, copyFileRule(
 			ctx, header, filepath.Join(includeDir, header.String())))
 	}
 
@@ -712,38 +725,18 @@
 		if !ok || !m.Enabled() || m.Name() == vndkUsingCoreVariantLibrariesTxt {
 			return
 		}
-		snapshotOutputs = append(snapshotOutputs, copyFile(
+		snapshotOutputs = append(snapshotOutputs, copyFileRule(
 			ctx, m.OutputFile(), filepath.Join(configsDir, m.Name())))
 	})
 
 	/*
-		Dump a map to a list file as:
-
-		{key1} {value1}
-		{key2} {value2}
-		...
-	*/
-	installMapListFile := func(m map[string]string, path string) android.OutputPath {
-		var txtBuilder strings.Builder
-		for idx, k := range android.SortedStringKeys(m) {
-			if idx > 0 {
-				txtBuilder.WriteString("\n")
-			}
-			txtBuilder.WriteString(k)
-			txtBuilder.WriteString(" ")
-			txtBuilder.WriteString(m[k])
-		}
-		return writeStringToFile(ctx, txtBuilder.String(), path)
-	}
-
-	/*
 		module_paths.txt contains paths on which VNDK modules are defined.
 		e.g.,
 			libbase.so system/libbase
 			libc.so bionic/libc
 			...
 	*/
-	snapshotOutputs = append(snapshotOutputs, installMapListFile(modulePaths, filepath.Join(configsDir, "module_paths.txt")))
+	snapshotOutputs = append(snapshotOutputs, installMapListFileRule(ctx, modulePaths, filepath.Join(configsDir, "module_paths.txt")))
 
 	/*
 		module_names.txt contains names as which VNDK modules are defined,
@@ -754,7 +747,7 @@
 			libprotobuf-cpp-full-3.9.2.so libprotobuf-cpp-full
 			...
 	*/
-	snapshotOutputs = append(snapshotOutputs, installMapListFile(moduleNames, filepath.Join(configsDir, "module_names.txt")))
+	snapshotOutputs = append(snapshotOutputs, installMapListFileRule(ctx, moduleNames, filepath.Join(configsDir, "module_names.txt")))
 
 	// All artifacts are ready. Sort them to normalize ninja and then zip.
 	sort.Slice(snapshotOutputs, func(i, j int) bool {
@@ -764,7 +757,7 @@
 	zipPath := android.PathForOutput(ctx, snapshotDir, "android-vndk-"+ctx.DeviceConfig().DeviceArch()+".zip")
 	zipRule := android.NewRuleBuilder(pctx, ctx)
 
-	// filenames in rspfile from FlagWithRspFileInputList might be single-quoted. Remove it with xargs
+	// filenames in rspfile from FlagWithRspFileInputList might be single-quoted. Remove it with tr
 	snapshotOutputList := android.PathForOutput(ctx, snapshotDir, "android-vndk-"+ctx.DeviceConfig().DeviceArch()+"_list")
 	zipRule.Command().
 		Text("tr").