diff --git a/aconfig/aconfig_declarations.go b/aconfig/aconfig_declarations.go
index 250fd56..d9a862c 100644
--- a/aconfig/aconfig_declarations.go
+++ b/aconfig/aconfig_declarations.go
@@ -88,6 +88,13 @@
 		ctx.PropertyErrorf("container", "missing container property")
 	}
 
+	// treating system_ext as system partition as we are combining them as one container
+	// TODO remove this logic once we start enforcing that system_ext cannot be specified as
+	// container in the container field.
+	if module.properties.Container == "system_ext" {
+		module.properties.Container = "system"
+	}
+
 	// Add a dependency on the aconfig_value_sets defined in
 	// RELEASE_ACONFIG_VALUE_SETS, and add any aconfig_values that
 	// match our package.
diff --git a/aconfig/aconfig_value_set.go b/aconfig/aconfig_value_set.go
index 7ba76c0..d72ec48 100644
--- a/aconfig/aconfig_value_set.go
+++ b/aconfig/aconfig_value_set.go
@@ -16,6 +16,9 @@
 
 import (
 	"android/soong/android"
+	"fmt"
+	"strings"
+
 	"github.com/google/blueprint"
 )
 
@@ -27,6 +30,9 @@
 	properties struct {
 		// aconfig_values modules
 		Values []string
+
+		// Paths to the Android.bp files where the aconfig_values modules are defined.
+		Srcs []string
 	}
 }
 
@@ -56,7 +62,35 @@
 
 var valueSetProviderKey = blueprint.NewProvider[valueSetProviderData]()
 
+func (module *ValueSetModule) FindAconfigValuesFromSrc(ctx android.BottomUpMutatorContext) map[string]android.Path {
+	moduleDir := ctx.ModuleDir()
+	srcs := android.PathsForModuleSrcExcludes(ctx, module.properties.Srcs, []string{ctx.BlueprintsFile()})
+
+	aconfigValuesPrefix := strings.Replace(module.Name(), "aconfig_value_set", "aconfig-values", 1)
+	moduleNamesSrcMap := make(map[string]android.Path)
+	for _, src := range srcs {
+		subDir := strings.TrimPrefix(src.String(), moduleDir+"/")
+		packageName, _, found := strings.Cut(subDir, "/")
+		if found {
+			moduleName := fmt.Sprintf("%s-%s-all", aconfigValuesPrefix, packageName)
+			moduleNamesSrcMap[moduleName] = src
+		}
+	}
+	return moduleNamesSrcMap
+}
+
 func (module *ValueSetModule) DepsMutator(ctx android.BottomUpMutatorContext) {
+
+	// TODO: b/366285733 - Replace the file path based solution with more robust solution.
+	aconfigValuesMap := module.FindAconfigValuesFromSrc(ctx)
+	for _, moduleName := range android.SortedKeys(aconfigValuesMap) {
+		if ctx.OtherModuleExists(moduleName) {
+			ctx.AddDependency(ctx.Module(), valueSetTag, moduleName)
+		} else {
+			ctx.ModuleErrorf("module %q not found. Rename the aconfig_values module defined in %q to %q", moduleName, aconfigValuesMap[moduleName], moduleName)
+		}
+	}
+
 	deps := ctx.AddDependency(ctx.Module(), valueSetTag, module.properties.Values...)
 	for _, dep := range deps {
 		_, ok := dep.(*ValuesModule)
diff --git a/aconfig/aconfig_value_set_test.go b/aconfig/aconfig_value_set_test.go
index 32c31cb..3b7281e 100644
--- a/aconfig/aconfig_value_set_test.go
+++ b/aconfig/aconfig_value_set_test.go
@@ -18,6 +18,8 @@
 	"testing"
 
 	"android/soong/android"
+
+	"github.com/google/blueprint"
 )
 
 func TestAconfigValueSet(t *testing.T) {
@@ -41,3 +43,112 @@
 	depData, _ := android.OtherModuleProvider(result, module, valueSetProviderKey)
 	android.AssertStringEquals(t, "AvailablePackages", "blah.aconfig_values", depData.AvailablePackages["foo.package"][0].String())
 }
+
+func TestAconfigValueSetBpGlob(t *testing.T) {
+	result := android.GroupFixturePreparers(
+		PrepareForTestWithAconfigBuildComponents,
+		android.FixtureMergeMockFs(
+			map[string][]byte{
+				// .../some_release/android.foo/
+				"some_release/android.foo/Android.bp": []byte(`
+				aconfig_values {
+					name: "aconfig-values-platform_build_release-some_release-android.foo-all",
+					package: "android.foo",
+					srcs: [
+						"*.textproto",
+					],
+				}
+				`),
+				"some_release/android.foo/flag.textproto": nil,
+
+				// .../some_release/android.bar/
+				"some_release/android.bar/Android.bp": []byte(`
+				aconfig_values {
+					name: "aconfig-values-platform_build_release-some_release-android.bar-all",
+					package: "android.bar",
+					srcs: [
+						"*.textproto",
+					],
+				}
+				`),
+				"some_release/android.bar/flag.textproto": nil,
+
+				// .../some_release/
+				"some_release/Android.bp": []byte(`
+				aconfig_value_set {
+					name: "aconfig_value_set-platform_build_release-some_release",
+					srcs: [
+						"*/Android.bp",
+					],
+				}
+				`),
+			},
+		),
+	).RunTest(t)
+
+	checkModuleHasDependency := func(name, variant, dep string) bool {
+		t.Helper()
+		module := result.ModuleForTests(name, variant).Module()
+		depFound := false
+		result.VisitDirectDeps(module, func(m blueprint.Module) {
+			if m.Name() == dep {
+				depFound = true
+			}
+		})
+		return depFound
+	}
+	android.AssertBoolEquals(t,
+		"aconfig_value_set expected to depend on aconfig_value via srcs",
+		true,
+		checkModuleHasDependency(
+			"aconfig_value_set-platform_build_release-some_release",
+			"",
+			"aconfig-values-platform_build_release-some_release-android.foo-all",
+		),
+	)
+	android.AssertBoolEquals(t,
+		"aconfig_value_set expected to depend on aconfig_value via srcs",
+		true,
+		checkModuleHasDependency(
+			"aconfig_value_set-platform_build_release-some_release",
+			"",
+			"aconfig-values-platform_build_release-some_release-android.bar-all",
+		),
+	)
+}
+
+func TestAconfigValueSetBpGlobError(t *testing.T) {
+	android.GroupFixturePreparers(
+		PrepareForTestWithAconfigBuildComponents,
+		android.FixtureMergeMockFs(
+			map[string][]byte{
+				// .../some_release/android.bar/
+				"some_release/android.bar/Android.bp": []byte(`
+				aconfig_values {
+					name: "aconfig-values-platform_build_release-some_release-android_bar-all",
+					package: "android.bar",
+					srcs: [
+						"*.textproto",
+					],
+				}
+				`),
+				"some_release/android.bar/flag.textproto": nil,
+
+				// .../some_release/
+				"some_release/Android.bp": []byte(`
+				aconfig_value_set {
+					name: "aconfig_value_set-platform_build_release-some_release",
+					srcs: [
+						"*/Android.bp",
+					],
+				}
+				`),
+			},
+		),
+	).ExtendWithErrorHandler(android.FixtureExpectsOneErrorPattern(
+		`module "aconfig_value_set-platform_build_release-some_release": module ` +
+			`"aconfig-values-platform_build_release-some_release-android.bar-all" not found. ` +
+			`Rename the aconfig_values module defined in "some_release/android.bar/Android.bp" ` +
+			`to "aconfig-values-platform_build_release-some_release-android.bar-all"`),
+	).RunTest(t)
+}
diff --git a/aconfig/codegen/java_aconfig_library_test.go b/aconfig/codegen/java_aconfig_library_test.go
index 87b54a4..d8372f3 100644
--- a/aconfig/codegen/java_aconfig_library_test.go
+++ b/aconfig/codegen/java_aconfig_library_test.go
@@ -260,7 +260,7 @@
 			aconfig_declarations {
 				name: "my_aconfig_declarations_bar",
 				package: "com.example.package.bar",
-				container: "system_ext",
+				container: "vendor",
 				srcs: ["bar.aconfig"],
 			}
 
diff --git a/android/aconfig_providers.go b/android/aconfig_providers.go
index cb88e01..d2a9622 100644
--- a/android/aconfig_providers.go
+++ b/android/aconfig_providers.go
@@ -233,7 +233,8 @@
 	} else if m.ProductSpecific() {
 		container = "product"
 	} else if m.SystemExtSpecific() {
-		container = "system_ext"
+		// system_ext and system partitions should be treated as one container
+		container = "system"
 	}
 
 	paths = append(paths, aconfigFiles[container]...)
diff --git a/android/arch.go b/android/arch.go
index a7868ba..942727a 100644
--- a/android/arch.go
+++ b/android/arch.go
@@ -396,20 +396,21 @@
 // device_supported and host_supported properties to determine which OsTypes are enabled for this
 // module, then searches through the Targets to determine which have enabled Targets for this
 // module.
-func osMutator(mctx BottomUpMutatorContext) {
-	module := mctx.Module()
-	base := module.base()
+type osTransitionMutator struct{}
 
-	// Nothing to do for modules that are not architecture specific (e.g. a genrule).
-	if !base.ArchSpecific() {
-		return
-	}
+type allOsInfo struct {
+	Os         map[string]OsType
+	Variations []string
+}
 
-	// Collect a list of OSTypes supported by this module based on the HostOrDevice value
-	// passed to InitAndroidArchModule and the device_supported and host_supported properties.
+var allOsProvider = blueprint.NewMutatorProvider[*allOsInfo]("os_propagate")
+
+// moduleOSList collects a list of OSTypes supported by this module based on the HostOrDevice
+// value passed to InitAndroidArchModule and the device_supported and host_supported properties.
+func moduleOSList(ctx ConfigContext, base *ModuleBase) []OsType {
 	var moduleOSList []OsType
 	for _, os := range osTypeList {
-		for _, t := range mctx.Config().Targets[os] {
+		for _, t := range ctx.Config().Targets[os] {
 			if base.supportsTarget(t) {
 				moduleOSList = append(moduleOSList, os)
 				break
@@ -417,53 +418,91 @@
 		}
 	}
 
-	createCommonOSVariant := base.commonProperties.CreateCommonOSVariant
+	if base.commonProperties.CreateCommonOSVariant {
+		// A CommonOS variant was requested so add it to the list of OS variants to
+		// create. It needs to be added to the end because it needs to depend on the
+		// the other variants and inter variant dependencies can only be created from a
+		// later variant in that list to an earlier one. That is because variants are
+		// always processed in the order in which they are created.
+		moduleOSList = append(moduleOSList, CommonOS)
+	}
+
+	return moduleOSList
+}
+
+func (o *osTransitionMutator) Split(ctx BaseModuleContext) []string {
+	module := ctx.Module()
+	base := module.base()
+
+	// Nothing to do for modules that are not architecture specific (e.g. a genrule).
+	if !base.ArchSpecific() {
+		return []string{""}
+	}
+
+	moduleOSList := moduleOSList(ctx, base)
 
 	// If there are no supported OSes then disable the module.
-	if len(moduleOSList) == 0 && !createCommonOSVariant {
+	if len(moduleOSList) == 0 {
 		base.Disable()
-		return
+		return []string{""}
 	}
 
 	// Convert the list of supported OsTypes to the variation names.
 	osNames := make([]string, len(moduleOSList))
+	osMapping := make(map[string]OsType, len(moduleOSList))
 	for i, os := range moduleOSList {
 		osNames[i] = os.String()
+		osMapping[osNames[i]] = os
 	}
 
-	if createCommonOSVariant {
-		// A CommonOS variant was requested so add it to the list of OS variants to
-		// create. It needs to be added to the end because it needs to depend on the
-		// the other variants in the list returned by CreateVariations(...) and inter
-		// variant dependencies can only be created from a later variant in that list to
-		// an earlier one. That is because variants are always processed in the order in
-		// which they are returned from CreateVariations(...).
-		osNames = append(osNames, CommonOS.Name)
-		moduleOSList = append(moduleOSList, CommonOS)
+	SetProvider(ctx, allOsProvider, &allOsInfo{
+		Os:         osMapping,
+		Variations: osNames,
+	})
+
+	return osNames
+}
+
+func (o *osTransitionMutator) OutgoingTransition(ctx OutgoingTransitionContext, sourceVariation string) string {
+	return sourceVariation
+}
+
+func (o *osTransitionMutator) IncomingTransition(ctx IncomingTransitionContext, incomingVariation string) string {
+	module := ctx.Module()
+	base := module.base()
+
+	if !base.ArchSpecific() {
+		return ""
 	}
 
-	// Create the variations, annotate each one with which OS it was created for, and
+	return incomingVariation
+}
+
+func (o *osTransitionMutator) Mutate(ctx BottomUpMutatorContext, variation string) {
+	module := ctx.Module()
+	base := module.base()
+
+	if variation == "" {
+		return
+	}
+
+	allOsInfo, ok := ModuleProvider(ctx, allOsProvider)
+	if !ok {
+		panic(fmt.Errorf("missing allOsProvider"))
+	}
+
+	// Annotate this variant with which OS it was created for, and
 	// squash the appropriate OS-specific properties into the top level properties.
-	modules := mctx.CreateVariations(osNames...)
-	for i, m := range modules {
-		m.base().commonProperties.CompileOS = moduleOSList[i]
-		m.base().setOSProperties(mctx)
-	}
+	base.commonProperties.CompileOS = allOsInfo.Os[variation]
+	base.setOSProperties(ctx)
 
-	if createCommonOSVariant {
+	if variation == CommonOS.String() {
 		// A CommonOS variant was requested so add dependencies from it (the last one in
 		// the list) to the OS type specific variants.
-		last := len(modules) - 1
-		commonOSVariant := modules[last]
-		commonOSVariant.base().commonProperties.CommonOSVariant = true
-		for _, module := range modules[0:last] {
-			// Ignore modules that are enabled. Note, this will only avoid adding
-			// dependencies on OsType variants that are explicitly disabled in their
-			// properties. The CommonOS variant will still depend on disabled variants
-			// if they are disabled afterwards, e.g. in archMutator if
-			if module.Enabled(mctx) {
-				mctx.AddInterVariantDependency(commonOsToOsSpecificVariantTag, commonOSVariant, module)
-			}
+		osList := allOsInfo.Variations[:len(allOsInfo.Variations)-1]
+		for _, os := range osList {
+			variation := []blueprint.Variation{{"os", os}}
+			ctx.AddVariationDependencies(variation, commonOsToOsSpecificVariantTag, ctx.ModuleName())
 		}
 	}
 }
@@ -496,7 +535,7 @@
 
 var DarwinUniversalVariantTag = archDepTag{name: "darwin universal binary"}
 
-// archMutator splits a module into a variant for each Target requested by the module.  Target selection
+// archTransitionMutator splits a module into a variant for each Target requested by the module.  Target selection
 // for a module is in three levels, OsClass, multilib, and then Target.
 // OsClass selection is determined by:
 //   - The HostOrDeviceSupported value passed in to InitAndroidArchModule by the module type factory, which selects
@@ -527,25 +566,32 @@
 //
 // Modules can be initialized with InitAndroidMultiTargetsArchModule, in which case they will be split by OsClass,
 // but will have a common Target that is expected to handle all other selected Targets via ctx.MultiTargets().
-func archMutator(mctx BottomUpMutatorContext) {
-	module := mctx.Module()
+type archTransitionMutator struct{}
+
+type allArchInfo struct {
+	Targets      map[string]Target
+	MultiTargets []Target
+	Primary      string
+	Multilib     string
+}
+
+var allArchProvider = blueprint.NewMutatorProvider[*allArchInfo]("arch_propagate")
+
+func (a *archTransitionMutator) Split(ctx BaseModuleContext) []string {
+	module := ctx.Module()
 	base := module.base()
 
 	if !base.ArchSpecific() {
-		return
+		return []string{""}
 	}
 
 	os := base.commonProperties.CompileOS
 	if os == CommonOS {
-		// Make sure that the target related properties are initialized for the
-		// CommonOS variant.
-		addTargetProperties(module, commonTargetMap[os.Name], nil, true)
-
 		// Do not create arch specific variants for the CommonOS variant.
-		return
+		return []string{""}
 	}
 
-	osTargets := mctx.Config().Targets[os]
+	osTargets := ctx.Config().Targets[os]
 
 	image := base.commonProperties.ImageVariation
 	// Filter NativeBridge targets unless they are explicitly supported.
@@ -572,19 +618,18 @@
 	prefer32 := os == Windows
 
 	// Determine the multilib selection for this module.
-	ignorePrefer32OnDevice := mctx.Config().IgnorePrefer32OnDevice()
-	multilib, extraMultilib := decodeMultilib(base, os, ignorePrefer32OnDevice)
+	multilib, extraMultilib := decodeMultilib(ctx, base)
 
 	// Convert the multilib selection into a list of Targets.
 	targets, err := decodeMultilibTargets(multilib, osTargets, prefer32)
 	if err != nil {
-		mctx.ModuleErrorf("%s", err.Error())
+		ctx.ModuleErrorf("%s", err.Error())
 	}
 
 	// If there are no supported targets disable the module.
 	if len(targets) == 0 {
 		base.Disable()
-		return
+		return []string{""}
 	}
 
 	// If the module is using extraMultilib, decode the extraMultilib selection into
@@ -593,7 +638,7 @@
 	if extraMultilib != "" {
 		multiTargets, err = decodeMultilibTargets(extraMultilib, osTargets, prefer32)
 		if err != nil {
-			mctx.ModuleErrorf("%s", err.Error())
+			ctx.ModuleErrorf("%s", err.Error())
 		}
 		multiTargets = filterHostCross(multiTargets, targets[0].HostCross)
 	}
@@ -601,7 +646,7 @@
 	// Recovery is always the primary architecture, filter out any other architectures.
 	// Common arch is also allowed
 	if image == RecoveryVariation {
-		primaryArch := mctx.Config().DevicePrimaryArchType()
+		primaryArch := ctx.Config().DevicePrimaryArchType()
 		targets = filterToArch(targets, primaryArch, Common)
 		multiTargets = filterToArch(multiTargets, primaryArch, Common)
 	}
@@ -609,37 +654,109 @@
 	// If there are no supported targets disable the module.
 	if len(targets) == 0 {
 		base.Disable()
-		return
+		return []string{""}
 	}
 
 	// Convert the targets into a list of arch variation names.
 	targetNames := make([]string, len(targets))
+	targetMapping := make(map[string]Target, len(targets))
 	for i, target := range targets {
 		targetNames[i] = target.ArchVariation()
+		targetMapping[targetNames[i]] = targets[i]
 	}
 
-	// Create the variations, annotate each one with which Target it was created for, and
-	// squash the appropriate arch-specific properties into the top level properties.
-	modules := mctx.CreateVariations(targetNames...)
-	for i, m := range modules {
-		addTargetProperties(m, targets[i], multiTargets, i == 0)
-		m.base().setArchProperties(mctx)
+	SetProvider(ctx, allArchProvider, &allArchInfo{
+		Targets:      targetMapping,
+		MultiTargets: multiTargets,
+		Primary:      targetNames[0],
+		Multilib:     multilib,
+	})
+	return targetNames
+}
 
-		// Install support doesn't understand Darwin+Arm64
-		if os == Darwin && targets[i].HostCross {
-			m.base().commonProperties.SkipInstall = true
+func (a *archTransitionMutator) OutgoingTransition(ctx OutgoingTransitionContext, sourceVariation string) string {
+	return sourceVariation
+}
+
+func (a *archTransitionMutator) IncomingTransition(ctx IncomingTransitionContext, incomingVariation string) string {
+	module := ctx.Module()
+	base := module.base()
+
+	if !base.ArchSpecific() {
+		return ""
+	}
+
+	os := base.commonProperties.CompileOS
+	if os == CommonOS {
+		// Do not create arch specific variants for the CommonOS variant.
+		return ""
+	}
+
+	if incomingVariation == "" {
+		multilib, _ := decodeMultilib(ctx, base)
+		if multilib == "common" {
+			return "common"
 		}
 	}
+	return incomingVariation
+}
+
+func (a *archTransitionMutator) Mutate(ctx BottomUpMutatorContext, variation string) {
+	module := ctx.Module()
+	base := module.base()
+	os := base.commonProperties.CompileOS
+
+	if os == CommonOS {
+		// Make sure that the target related properties are initialized for the
+		// CommonOS variant.
+		addTargetProperties(module, commonTargetMap[os.Name], nil, true)
+		return
+	}
+
+	if variation == "" {
+		return
+	}
+
+	if !base.ArchSpecific() {
+		panic(fmt.Errorf("found variation %q for non arch specifc module", variation))
+	}
+
+	allArchInfo, ok := ModuleProvider(ctx, allArchProvider)
+	if !ok {
+		return
+	}
+
+	target, ok := allArchInfo.Targets[variation]
+	if !ok {
+		panic(fmt.Errorf("missing Target for %q", variation))
+	}
+	primary := variation == allArchInfo.Primary
+	multiTargets := allArchInfo.MultiTargets
+
+	// Annotate the new variant with which Target it was created for, and
+	// squash the appropriate arch-specific properties into the top level properties.
+	addTargetProperties(ctx.Module(), target, multiTargets, primary)
+	base.setArchProperties(ctx)
+
+	// Install support doesn't understand Darwin+Arm64
+	if os == Darwin && target.HostCross {
+		base.commonProperties.SkipInstall = true
+	}
 
 	// Create a dependency for Darwin Universal binaries from the primary to secondary
 	// architecture. The module itself will be responsible for calling lipo to merge the outputs.
 	if os == Darwin {
-		if multilib == "darwin_universal" && len(modules) == 2 {
-			mctx.AddInterVariantDependency(DarwinUniversalVariantTag, modules[1], modules[0])
-		} else if multilib == "darwin_universal_common_first" && len(modules) == 3 {
-			mctx.AddInterVariantDependency(DarwinUniversalVariantTag, modules[2], modules[1])
+		isUniversalBinary := (allArchInfo.Multilib == "darwin_universal" && len(allArchInfo.Targets) == 2) ||
+			allArchInfo.Multilib == "darwin_universal_common_first" && len(allArchInfo.Targets) == 3
+		isPrimary := variation == ctx.Config().BuildArch.String()
+		hasSecondaryConfigured := len(ctx.Config().Targets[Darwin]) > 1
+		if isUniversalBinary && isPrimary && hasSecondaryConfigured {
+			secondaryArch := ctx.Config().Targets[Darwin][1].Arch.String()
+			variation := []blueprint.Variation{{"arch", secondaryArch}}
+			ctx.AddVariationDependencies(variation, DarwinUniversalVariantTag, ctx.ModuleName())
 		}
 	}
+
 }
 
 // addTargetProperties annotates a variant with the Target is is being compiled for, the list
@@ -656,7 +773,9 @@
 // multilib from the factory's call to InitAndroidArchModule if none was set.  For modules that
 // called InitAndroidMultiTargetsArchModule it always returns "common" for multilib, and returns
 // the actual multilib in extraMultilib.
-func decodeMultilib(base *ModuleBase, os OsType, ignorePrefer32OnDevice bool) (multilib, extraMultilib string) {
+func decodeMultilib(ctx ConfigContext, base *ModuleBase) (multilib, extraMultilib string) {
+	os := base.commonProperties.CompileOS
+	ignorePrefer32OnDevice := ctx.Config().IgnorePrefer32OnDevice()
 	// First check the "android.compile_multilib" or "host.compile_multilib" properties.
 	switch os.Class {
 	case Device:
diff --git a/android/arch_test.go b/android/arch_test.go
index 6134a06..57c9010 100644
--- a/android/arch_test.go
+++ b/android/arch_test.go
@@ -451,7 +451,7 @@
 
 	for _, tt := range testCases {
 		t.Run(tt.name, func(t *testing.T) {
-			if tt.goOS != runtime.GOOS {
+			if tt.goOS != "" && tt.goOS != runtime.GOOS {
 				t.Skipf("requries runtime.GOOS %s", tt.goOS)
 			}
 
diff --git a/android/module.go b/android/module.go
index 47fdc23..f5a611c 100644
--- a/android/module.go
+++ b/android/module.go
@@ -443,12 +443,6 @@
 	// Set at module initialization time by calling InitCommonOSAndroidMultiTargetsArchModule
 	CreateCommonOSVariant bool `blueprint:"mutated"`
 
-	// If set to true then this variant is the CommonOS variant that has dependencies on its
-	// OsType specific variants.
-	//
-	// Set by osMutator.
-	CommonOSVariant bool `blueprint:"mutated"`
-
 	// When set to true, this module is not installed to the full install path (ex: under
 	// out/target/product/<name>/<partition>). It can be installed only to the packaging
 	// modules like android_filesystem.
@@ -1221,7 +1215,7 @@
 
 // True if the current variant is a CommonOS variant, false otherwise.
 func (m *ModuleBase) IsCommonOSVariant() bool {
-	return m.commonProperties.CommonOSVariant
+	return m.commonProperties.CompileOS == CommonOS
 }
 
 // supportsTarget returns true if the given Target is supported by the current module.
@@ -1346,6 +1340,14 @@
 	return m.commonProperties.Enabled.GetOrDefault(m.ConfigurableEvaluator(ctx), !m.Os().DefaultDisabled)
 }
 
+// Returns a copy of the enabled property, useful for passing it on to sub-modules
+func (m *ModuleBase) EnabledProperty() proptools.Configurable[bool] {
+	if m.commonProperties.ForcedDisabled {
+		return proptools.NewSimpleConfigurable(false)
+	}
+	return m.commonProperties.Enabled.Clone()
+}
+
 func (m *ModuleBase) Disable() {
 	m.commonProperties.ForcedDisabled = true
 }
@@ -2204,9 +2206,14 @@
 	return proptools.Bool(m.commonProperties.Native_bridge_supported)
 }
 
+type ConfigContext interface {
+	Config() Config
+}
+
 type ConfigurableEvaluatorContext interface {
 	Config() Config
 	OtherModulePropertyErrorf(module Module, property string, fmt string, args ...interface{})
+	HasMutatorFinished(mutatorName string) bool
 }
 
 type configurationEvalutor struct {
@@ -2228,6 +2235,12 @@
 func (e configurationEvalutor) EvaluateConfiguration(condition proptools.ConfigurableCondition, property string) proptools.ConfigurableValue {
 	ctx := e.ctx
 	m := e.m
+
+	if !ctx.HasMutatorFinished("defaults") {
+		ctx.OtherModulePropertyErrorf(m, property, "Cannot evaluate configurable property before the defaults mutator has run")
+		return proptools.ConfigurableValueUndefined()
+	}
+
 	switch condition.FunctionName() {
 	case "release_flag":
 		if condition.NumArgs() != 1 {
diff --git a/android/mutator.go b/android/mutator.go
index 2ef4d7f..18a9777 100644
--- a/android/mutator.go
+++ b/android/mutator.go
@@ -148,9 +148,9 @@
 }
 
 func registerArchMutator(ctx RegisterMutatorsContext) {
-	ctx.BottomUp("os", osMutator).Parallel()
+	ctx.Transition("os", &osTransitionMutator{})
 	ctx.Transition("image", &imageTransitionMutator{})
-	ctx.BottomUp("arch", archMutator).Parallel()
+	ctx.Transition("arch", &archTransitionMutator{})
 }
 
 var preDeps = []RegisterMutatorFunc{
diff --git a/android/packaging_test.go b/android/packaging_test.go
index 0f7bb39..f5b1020 100644
--- a/android/packaging_test.go
+++ b/android/packaging_test.go
@@ -118,6 +118,7 @@
 	}
 
 	result := GroupFixturePreparers(
+		PrepareForTestWithDefaults,
 		PrepareForTestWithArchMutator,
 		FixtureRegisterWithContext(func(ctx RegistrationContext) {
 			ctx.RegisterModuleType("component", componentTestModuleFactory)
diff --git a/cc/config/global.go b/cc/config/global.go
index c838357..9d3de6d 100644
--- a/cc/config/global.go
+++ b/cc/config/global.go
@@ -286,6 +286,8 @@
 		// New warnings to be fixed after clang-r468909
 		"-Wno-error=deprecated-builtins", // http://b/241601211
 		"-Wno-error=deprecated",          // in external/googletest/googletest
+		// Disabling until the warning is fixed in libc++abi header files b/366180429
+		"-Wno-deprecated-dynamic-exception-spec",
 		// New warnings to be fixed after clang-r475365
 		"-Wno-error=enum-constexpr-conversion", // http://b/243964282
 		// New warnings to be fixed after clang-r522817
diff --git a/docs/tidy.md b/docs/tidy.md
index ae0ca93..2e4c957 100644
--- a/docs/tidy.md
+++ b/docs/tidy.md
@@ -38,7 +38,7 @@
 clang-tidy is enabled explicitly and with a different check list:
 ```
 cc_defaults {
-    name: "bpf_defaults",
+    name: "bpf_cc_defaults",
     // snipped
     tidy: true,
     tidy_checks: [
@@ -52,7 +52,7 @@
 }
 ```
 That means in normal builds, even without `WITH_TIDY=1`,
-the modules that use `bpf_defaults` _should_ run clang-tidy
+the modules that use `bpf_cc_defaults` _should_ run clang-tidy
 over C/C++ source files with the given `tidy_checks`.
 
 However since clang-tidy warnings and its runtime cost might
diff --git a/filesystem/system_image.go b/filesystem/system_image.go
index a8fd368..805249e 100644
--- a/filesystem/system_image.go
+++ b/filesystem/system_image.go
@@ -27,7 +27,7 @@
 
 type systemImageProperties struct {
 	// Path to the input linker config json file.
-	Linker_config_src *string
+	Linker_config_src *string `android:"path"`
 }
 
 // android_system_image is a specialization of android_filesystem for the 'system' partition.
diff --git a/golang/golang.go b/golang/golang.go
index ede2150..618a085 100644
--- a/golang/golang.go
+++ b/golang/golang.go
@@ -96,17 +96,31 @@
 	outputFile := android.PathForArbitraryOutput(ctx, android.Rel(ctx, ctx.Config().OutDir(), g.IntermediateFile())).WithoutRel()
 	g.outputFile = outputFile
 
-	installPath := ctx.InstallFile(android.PathForModuleInstall(ctx, "bin"), ctx.ModuleName(), outputFile)
+	// Don't create install rules for modules used by bootstrap, the install command line will differ from
+	// what was used during bootstrap, which will cause ninja to rebuild the module on the next run,
+	// triggering reanalysis.
+	if !usedByBootstrap(ctx.ModuleName()) {
+		installPath := ctx.InstallFile(android.PathForModuleInstall(ctx, "bin"), ctx.ModuleName(), outputFile)
 
-	if !ctx.Config().KatiEnabled() || g.ExportedToMake() {
 		// Modules in an unexported namespace have no install rule, only add modules in the exported namespaces
 		// to the blueprint_tools phony rules.
-		ctx.Phony("blueprint_tools", installPath)
+		if !ctx.Config().KatiEnabled() || g.ExportedToMake() {
+			ctx.Phony("blueprint_tools", installPath)
+		}
 	}
 
 	ctx.SetOutputFiles(android.Paths{outputFile}, "")
 }
 
+func usedByBootstrap(name string) bool {
+	switch name {
+	case "loadplugins", "soong_build":
+		return true
+	default:
+		return false
+	}
+}
+
 func (g *GoBinary) HostToolPath() android.OptionalPath {
 	return android.OptionalPathForPath(g.outputFile)
 }
diff --git a/java/config/kotlin.go b/java/config/kotlin.go
index e5e187c..302d021 100644
--- a/java/config/kotlin.go
+++ b/java/config/kotlin.go
@@ -50,4 +50,11 @@
 	}, " "))
 
 	pctx.StaticVariable("KotlincGlobalFlags", strings.Join([]string{}, " "))
+	// Use KotlincKytheGlobalFlags to prevent kotlinc version skew issues between android and
+	// g3 kythe indexers.
+	// This is necessary because there might be instances of kotlin code in android
+	// platform that are not fully compatible with the kotlinc used in g3 kythe indexers.
+	// e.g. uninitialized variables are a warning in 1.*, but an error in 2.*
+	// https://github.com/JetBrains/kotlin/blob/master/compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt#L748
+	pctx.StaticVariable("KotlincKytheGlobalFlags", strings.Join([]string{"-language-version 1.9"}, " "))
 }
diff --git a/java/dex.go b/java/dex.go
index 7d42efc..9d12b9a 100644
--- a/java/dex.go
+++ b/java/dex.go
@@ -245,6 +245,16 @@
 	if err != nil {
 		ctx.PropertyErrorf("min_sdk_version", "%s", err)
 	}
+	if !Bool(d.dexProperties.No_dex_container) && effectiveVersion.FinalOrFutureInt() >= 36 {
+		// W is 36, but we have not bumped the SDK version yet, so check for both.
+		if ctx.Config().PlatformSdkVersion().FinalInt() >= 36 ||
+			ctx.Config().PlatformSdkCodename() == "Wear" {
+			// TODO(b/329465418): Skip this module since it causes issue with app DRM
+			if ctx.ModuleName() != "framework-minus-apex" {
+				flags = append([]string{"-JDcom.android.tools.r8.dexContainerExperiment"}, flags...)
+			}
+		}
+	}
 
 	// If the specified SDK level is 10000, then configure the compiler to use the
 	// current platform SDK level and to compile the build as a platform build.
diff --git a/java/kotlin.go b/java/kotlin.go
index 3573f1e..f42d163 100644
--- a/java/kotlin.go
+++ b/java/kotlin.go
@@ -65,8 +65,6 @@
 	"headerClassesDir", "headerJar", "kotlinJvmTarget", "kotlinBuildFile", "emptyDir", "name")
 
 var kotlinKytheExtract = pctx.AndroidStaticRule("kotlinKythe",
-	// TODO (b/265428637): To prevent kotlinc version skew between android builds and internal kotlin indexers (g3), consider embedding the kotlinc used by android into the kzip file.
-	// This has an impact on .kzip sizes, so defer that for now.
 	blueprint.RuleParams{
 		Command: `rm -rf "$srcJarDir" && mkdir -p "$srcJarDir" && ` +
 			`${config.ZipSyncCmd} -d $srcJarDir -l $srcJarDir/list -f "*.java" -f "*.kt" $srcJars && ` +
@@ -76,7 +74,8 @@
 			// Skip header jars, those should not have an effect on kythe results.
 			` --args '${config.KotlincGlobalFlags} ` +
 			` ${config.KotlincSuppressJDK9Warnings} ${config.JavacHeapFlags} ` +
-			` $kotlincFlags -jvm-target $kotlinJvmTarget'`,
+			` $kotlincFlags -jvm-target $kotlinJvmTarget ` +
+			`${config.KotlincKytheGlobalFlags}'`,
 		CommandDeps: []string{
 			"${config.KotlinKytheExtractor}",
 			"${config.ZipSyncCmd}",
diff --git a/java/ravenwood.go b/java/ravenwood.go
index bb136cf..3fa73e6 100644
--- a/java/ravenwood.go
+++ b/java/ravenwood.go
@@ -33,7 +33,6 @@
 var ravenwoodLibContentTag = dependencyTag{name: "ravenwoodlibcontent"}
 var ravenwoodUtilsTag = dependencyTag{name: "ravenwoodutils"}
 var ravenwoodRuntimeTag = dependencyTag{name: "ravenwoodruntime"}
-var ravenwoodDataTag = dependencyTag{name: "ravenwooddata"}
 var ravenwoodTestResourceApkTag = dependencyTag{name: "ravenwoodtestresapk"}
 
 const ravenwoodUtilsName = "ravenwood-utils"
@@ -228,7 +227,10 @@
 	Jni_libs []string
 
 	// We use this to copy framework-res.apk to the ravenwood runtime directory.
-	Data []string
+	Data []string `android:"path,arch_variant"`
+
+	// We use this to copy font files to the ravenwood runtime directory.
+	Fonts []string `android:"path,arch_variant"`
 }
 
 type ravenwoodLibgroup struct {
@@ -267,9 +269,6 @@
 	for _, lib := range r.ravenwoodLibgroupProperties.Jni_libs {
 		ctx.AddVariationDependencies(ctx.Config().BuildOSTarget.Variations(), jniLibTag, lib)
 	}
-	for _, data := range r.ravenwoodLibgroupProperties.Data {
-		ctx.AddVariationDependencies(nil, ravenwoodDataTag, data)
-	}
 }
 
 func (r *ravenwoodLibgroup) GenerateAndroidBuildActions(ctx android.ModuleContext) {
@@ -309,12 +308,17 @@
 	}
 
 	dataInstallPath := installPath.Join(ctx, "ravenwood-data")
-	for _, data := range r.ravenwoodLibgroupProperties.Data {
-		libModule := ctx.GetDirectDepWithTag(data, ravenwoodDataTag)
-		file := android.OutputFileForModule(ctx, libModule, "")
+	data := android.PathsForModuleSrc(ctx, r.ravenwoodLibgroupProperties.Data)
+	for _, file := range data {
 		ctx.InstallFile(dataInstallPath, file.Base(), file)
 	}
 
+	fontsInstallPath := installPath.Join(ctx, "fonts")
+	fonts := android.PathsForModuleSrc(ctx, r.ravenwoodLibgroupProperties.Fonts)
+	for _, file := range fonts {
+		ctx.InstallFile(fontsInstallPath, file.Base(), file)
+	}
+
 	// Normal build should perform install steps
 	ctx.Phony(r.BaseModuleName(), android.PathForPhony(ctx, r.BaseModuleName()+"-install"))
 }
diff --git a/java/ravenwood_test.go b/java/ravenwood_test.go
index d26db93..0a1b089 100644
--- a/java/ravenwood_test.go
+++ b/java/ravenwood_test.go
@@ -19,6 +19,7 @@
 	"testing"
 
 	"android/soong/android"
+	"android/soong/etc"
 )
 
 var prepareRavenwoodRuntime = android.GroupFixturePreparers(
@@ -59,11 +60,15 @@
 		}
 		android_app {
 			name: "app1",
-            sdk_version: "current",
+			sdk_version: "current",
 		}
 		android_app {
 			name: "app2",
-            sdk_version: "current",
+			sdk_version: "current",
+		}
+		prebuilt_font {
+			name: "Font.ttf",
+			src: "Font.ttf",
 		}
 		android_ravenwood_libgroup {
 			name: "ravenwood-runtime",
@@ -76,7 +81,10 @@
 				"ravenwood-runtime-jni2",
 			],
 			data: [
-				"app1",
+				":app1",
+			],
+			fonts: [
+				":Font.ttf"
 			],
 		}
 		android_ravenwood_libgroup {
@@ -97,6 +105,7 @@
 
 	ctx := android.GroupFixturePreparers(
 		PrepareForIntegrationTestWithJava,
+		etc.PrepareForTestWithPrebuiltEtc,
 		prepareRavenwoodRuntime,
 	).RunTest(t)
 
@@ -114,6 +123,7 @@
 	runtime.Output(installPathPrefix + "/ravenwood-runtime/lib64/libred.so")
 	runtime.Output(installPathPrefix + "/ravenwood-runtime/lib64/ravenwood-runtime-jni3.so")
 	runtime.Output(installPathPrefix + "/ravenwood-runtime/ravenwood-data/app1.apk")
+	runtime.Output(installPathPrefix + "/ravenwood-runtime/fonts/Font.ttf")
 	utils := ctx.ModuleForTests("ravenwood-utils", "android_common")
 	utils.Output(installPathPrefix + "/ravenwood-utils/framework-rules.ravenwood.jar")
 }
@@ -125,29 +135,30 @@
 
 	ctx := android.GroupFixturePreparers(
 		PrepareForIntegrationTestWithJava,
+		etc.PrepareForTestWithPrebuiltEtc,
 		prepareRavenwoodRuntime,
 	).RunTestWithBp(t, `
-	cc_library_shared {
-		name: "jni-lib1",
-		host_supported: true,
-		srcs: ["jni.cpp"],
-	}
-	cc_library_shared {
-		name: "jni-lib2",
-		host_supported: true,
-		srcs: ["jni.cpp"],
-		stem: "libblue",
-		shared_libs: [
-			"jni-lib3",
-		],
-	}
-	cc_library_shared {
-		name: "jni-lib3",
-		host_supported: true,
-		srcs: ["jni.cpp"],
-		stem: "libpink",
-	}
-	android_ravenwood_test {
+		cc_library_shared {
+			name: "jni-lib1",
+			host_supported: true,
+			srcs: ["jni.cpp"],
+		}
+		cc_library_shared {
+			name: "jni-lib2",
+			host_supported: true,
+			srcs: ["jni.cpp"],
+			stem: "libblue",
+			shared_libs: [
+				"jni-lib3",
+			],
+		}
+		cc_library_shared {
+			name: "jni-lib3",
+			host_supported: true,
+			srcs: ["jni.cpp"],
+			stem: "libpink",
+		}
+		android_ravenwood_test {
 			name: "ravenwood-test",
 			srcs: ["Test.java"],
 			jni_libs: [
diff --git a/java/sdk_library.go b/java/sdk_library.go
index 725aaed..9f0564a 100644
--- a/java/sdk_library.go
+++ b/java/sdk_library.go
@@ -1727,6 +1727,7 @@
 	staticLibs.AppendSimpleValue(module.sdkLibraryProperties.Impl_only_static_libs)
 	props := struct {
 		Name           *string
+		Enabled        proptools.Configurable[bool]
 		Visibility     []string
 		Libs           []string
 		Static_libs    proptools.Configurable[[]string]
@@ -1734,6 +1735,7 @@
 		Stem           *string
 	}{
 		Name:       proptools.StringPtr(module.implLibraryModuleName()),
+		Enabled:    module.EnabledProperty(),
 		Visibility: visibility,
 
 		Libs: append(module.properties.Libs, module.sdkLibraryProperties.Impl_only_libs...),
@@ -1762,6 +1764,7 @@
 
 type libraryProperties struct {
 	Name           *string
+	Enabled        proptools.Configurable[bool]
 	Visibility     []string
 	Srcs           []string
 	Installable    *bool
@@ -1788,6 +1791,7 @@
 
 func (module *SdkLibrary) stubsLibraryProps(mctx android.DefaultableHookContext, apiScope *apiScope) libraryProperties {
 	props := libraryProperties{}
+	props.Enabled = module.EnabledProperty()
 	props.Visibility = []string{"//visibility:override", "//visibility:private"}
 	// sources are generated from the droiddoc
 	sdkVersion := module.sdkVersionForStubsLibrary(mctx, apiScope)
@@ -1838,6 +1842,7 @@
 func (module *SdkLibrary) createStubsSourcesAndApi(mctx android.DefaultableHookContext, apiScope *apiScope, name string, scopeSpecificDroidstubsArgs []string) {
 	props := struct {
 		Name                             *string
+		Enabled                          proptools.Configurable[bool]
 		Visibility                       []string
 		Srcs                             []string
 		Installable                      *bool
@@ -1879,6 +1884,7 @@
 	// * libs (static_libs/libs)
 
 	props.Name = proptools.StringPtr(name)
+	props.Enabled = module.EnabledProperty()
 	props.Visibility = childModuleVisibility(module.sdkLibraryProperties.Stubs_source_visibility)
 	props.Srcs = append(props.Srcs, module.properties.Srcs...)
 	props.Srcs = append(props.Srcs, module.sdkLibraryProperties.Api_srcs...)
@@ -2004,6 +2010,7 @@
 func (module *SdkLibrary) createApiLibrary(mctx android.DefaultableHookContext, apiScope *apiScope) {
 	props := struct {
 		Name              *string
+		Enabled           proptools.Configurable[bool]
 		Visibility        []string
 		Api_contributions []string
 		Libs              proptools.Configurable[[]string]
@@ -2016,6 +2023,7 @@
 	}{}
 
 	props.Name = proptools.StringPtr(module.apiLibraryModuleName(apiScope))
+	props.Enabled = module.EnabledProperty()
 	props.Visibility = []string{"//visibility:override", "//visibility:private"}
 
 	apiContributions := []string{}
@@ -2066,6 +2074,7 @@
 func (module *SdkLibrary) topLevelStubsLibraryProps(mctx android.DefaultableHookContext, apiScope *apiScope, doDist bool) libraryProperties {
 	props := libraryProperties{}
 
+	props.Enabled = module.EnabledProperty()
 	props.Visibility = childModuleVisibility(module.sdkLibraryProperties.Stubs_library_visibility)
 	sdkVersion := module.sdkVersionForStubsLibrary(mctx, apiScope)
 	props.Sdk_version = proptools.StringPtr(sdkVersion)
@@ -2158,6 +2167,7 @@
 	}
 	props := struct {
 		Name                      *string
+		Enabled                   proptools.Configurable[bool]
 		Lib_name                  *string
 		Apex_available            []string
 		On_bootclasspath_since    *string
@@ -2168,6 +2178,7 @@
 		Uses_libs_dependencies    []string
 	}{
 		Name:                      proptools.StringPtr(module.xmlPermissionsModuleName()),
+		Enabled:                   module.EnabledProperty(),
 		Lib_name:                  proptools.StringPtr(module.BaseModuleName()),
 		Apex_available:            module.ApexProperties.Apex_available,
 		On_bootclasspath_since:    module.commonSdkLibraryProperties.On_bootclasspath_since,
@@ -2263,11 +2274,6 @@
 // runtime libs and xml file. If requested, the stubs and docs are created twice
 // once for public API level and once for system API level
 func (module *SdkLibrary) CreateInternalModules(mctx android.DefaultableHookContext) {
-	// If the module has been disabled then don't create any child modules.
-	if !module.Enabled(mctx) {
-		return
-	}
-
 	if len(module.properties.Srcs) == 0 {
 		mctx.PropertyErrorf("srcs", "java_sdk_library must specify srcs")
 		return
diff --git a/rust/clippy.go b/rust/clippy.go
index 6f0ed7f..426fd73 100644
--- a/rust/clippy.go
+++ b/rust/clippy.go
@@ -38,11 +38,14 @@
 }
 
 func (c *clippy) flags(ctx ModuleContext, flags Flags, deps PathDeps) (Flags, PathDeps) {
-	enabled, lints, err := config.ClippyLintsForDir(ctx.ModuleDir(), c.Properties.Clippy_lints)
+	dirEnabled, lints, err := config.ClippyLintsForDir(ctx.ModuleDir(), c.Properties.Clippy_lints)
 	if err != nil {
 		ctx.PropertyErrorf("clippy_lints", err.Error())
 	}
-	flags.Clippy = enabled
+
+	envDisable := ctx.Config().IsEnvTrue("SOONG_DISABLE_CLIPPY")
+
+	flags.Clippy = dirEnabled && !envDisable
 	flags.ClippyFlags = append(flags.ClippyFlags, lints)
 	return flags, deps
 }
diff --git a/rust/coverage.go b/rust/coverage.go
index 91a7806..381fcf1 100644
--- a/rust/coverage.go
+++ b/rust/coverage.go
@@ -87,10 +87,6 @@
 }
 
 func (cov *coverage) begin(ctx BaseModuleContext) {
-	if ctx.Host() {
-		// Host coverage not yet supported.
-	} else {
-		// Update useSdk and sdkVersion args if Rust modules become SDK aware.
-		cov.Properties = cc.SetCoverageProperties(ctx, cov.Properties, ctx.RustModule().nativeCoverage(), false, "")
-	}
+	// Update useSdk and sdkVersion args if Rust modules become SDK aware.
+	cov.Properties = cc.SetCoverageProperties(ctx, cov.Properties, ctx.RustModule().nativeCoverage(), false, "")
 }
diff --git a/scripts/check_prebuilt_presigned_apk.py b/scripts/check_prebuilt_presigned_apk.py
index abab2e1..db64f90 100755
--- a/scripts/check_prebuilt_presigned_apk.py
+++ b/scripts/check_prebuilt_presigned_apk.py
@@ -36,7 +36,7 @@
                 if fail:
                     sys.exit(args.apk + ': Contains compressed JNI libraries')
                 return True
-            # It's ok for non-privileged apps to have compressed dex files, see go/gms-uncompressed-jni-slides
+            # It's ok for non-privileged apps to have compressed dex files
             if args.privileged and args.uncompress_priv_app_dex:
                 if info.filename.endswith('.dex') and info.compress_type != zipfile.ZIP_STORED:
                     if fail:
@@ -46,6 +46,10 @@
 
 
 def main():
+    # This script enforces requirements for presigned apps as documented in:
+    # go/gms-uncompressed-jni-slides
+    # https://docs.partner.android.com/gms/building/integrating/jni-libs
+    # https://docs.partner.android.com/gms/policies/domains/mba#jni-lib
     parser = argparse.ArgumentParser()
     parser.add_argument('--aapt2', help = "the path to the aapt2 executable")
     parser.add_argument('--zipalign', help = "the path to the zipalign executable")
diff --git a/scripts/manifest.py b/scripts/manifest.py
index 81f9c61..32603e8 100755
--- a/scripts/manifest.py
+++ b/scripts/manifest.py
@@ -23,9 +23,40 @@
 android_ns = 'http://schemas.android.com/apk/res/android'
 
 
+def get_or_create_applications(doc, manifest):
+  """Get all <application> tags from the manifest, or create one if none exist.
+  Multiple <application> tags may exist when manifest feature flagging is used.
+  """
+  applications = get_children_with_tag(manifest, 'application')
+  if len(applications) == 0:
+    application = doc.createElement('application')
+    indent = get_indent(manifest.firstChild, 1)
+    first = manifest.firstChild
+    manifest.insertBefore(doc.createTextNode(indent), first)
+    manifest.insertBefore(application, first)
+    applications.append(application)
+  return applications
+
+
+def get_or_create_uses_sdks(doc, manifest):
+  """Get all <uses-sdk> tags from the manifest, or create one if none exist.
+  Multiple <uses-sdk> tags may exist when manifest feature flagging is used.
+  """
+  uses_sdks = get_children_with_tag(manifest, 'uses-sdk')
+  if len(uses_sdks) == 0:
+    uses_sdk = doc.createElement('uses-sdk')
+    indent = get_indent(manifest.firstChild, 1)
+    manifest.insertBefore(uses_sdk, manifest.firstChild)
+
+    # Insert an indent before uses-sdk to line it up with the indentation of the
+    # other children of the <manifest> tag.
+    manifest.insertBefore(doc.createTextNode(indent), manifest.firstChild)
+    uses_sdks.append(uses_sdk)
+  return uses_sdks
+
 def get_children_with_tag(parent, tag_name):
   children = []
-  for child in  parent.childNodes:
+  for child in parent.childNodes:
     if child.nodeType == minidom.Node.ELEMENT_NODE and \
        child.tagName == tag_name:
       children.append(child)
diff --git a/scripts/manifest_check.py b/scripts/manifest_check.py
index b101259..1e32d1d 100755
--- a/scripts/manifest_check.py
+++ b/scripts/manifest_check.py
@@ -25,10 +25,7 @@
 import sys
 from xml.dom import minidom
 
-from manifest import android_ns
-from manifest import get_children_with_tag
-from manifest import parse_manifest
-from manifest import write_xml
+from manifest import *
 
 
 class ManifestMismatchError(Exception):
@@ -122,7 +119,7 @@
     # handles module names specified in Android.bp properties. However not all
     # <uses-library> entries in the manifest correspond to real modules: some of
     # the optional libraries may be missing at build time. Therefor this script
-    # accepts raw module names as spelled in Android.bp/Amdroid.mk and trims the
+    # accepts raw module names as spelled in Android.bp/Android.mk and trims the
     # optional namespace part manually.
     required = trim_namespace_parts(required)
     optional = trim_namespace_parts(optional)
@@ -205,15 +202,9 @@
     """Extract <uses-library> tags from the manifest."""
 
     manifest = parse_manifest(xml)
-    elems = get_children_with_tag(manifest, 'application')
-    if len(elems) > 1:
-        raise RuntimeError('found multiple <application> tags')
-    if not elems:
-        return [], [], []
-
-    application = elems[0]
-
-    libs = get_children_with_tag(application, 'uses-library')
+    libs = [child
+            for application in get_or_create_applications(xml, manifest)
+            for child in get_children_with_tag(application, 'uses-library')]
 
     required = [uses_library_name(x) for x in libs if uses_library_required(x)]
     optional = [
@@ -266,7 +257,7 @@
     manifest: manifest (either parsed XML or aapt dump of APK)
     is_apk:   if the manifest comes from an APK or an XML file
     """
-    if is_apk: #pylint: disable=no-else-return
+    if is_apk:  #pylint: disable=no-else-return
         return extract_target_sdk_version_apk(manifest)
     else:
         return extract_target_sdk_version_xml(manifest)
@@ -376,7 +367,7 @@
 
             # Create a status file that is empty on success, or contains an
             # error message on failure. When exceptions are suppressed,
-            # dexpreopt command command will check file size to determine if
+            # dexpreopt command will check file size to determine if
             # the check has failed.
             if args.enforce_uses_libraries_status:
                 with open(args.enforce_uses_libraries_status, 'w') as f:
@@ -386,7 +377,7 @@
         if args.extract_target_sdk_version:
             try:
                 print(extract_target_sdk_version(manifest, is_apk))
-            except: #pylint: disable=bare-except
+            except:  #pylint: disable=bare-except
                 # Failed; don't crash, return "any" SDK version. This will
                 # result in dexpreopt not adding any compatibility libraries.
                 print(10000)
diff --git a/scripts/manifest_check_test.py b/scripts/manifest_check_test.py
index 8003b3e..abe0d8b 100755
--- a/scripts/manifest_check_test.py
+++ b/scripts/manifest_check_test.py
@@ -44,8 +44,8 @@
 class EnforceUsesLibrariesTest(unittest.TestCase):
     """Unit tests for add_extract_native_libs function."""
 
-    def run_test(self, xml, apk, uses_libraries=[], optional_uses_libraries=[],
-                 missing_optional_uses_libraries=[]): #pylint: disable=dangerous-default-value
+    def run_test(self, xml, apk, uses_libraries=(), optional_uses_libraries=(),
+                 missing_optional_uses_libraries=()):  #pylint: disable=dangerous-default-value
         doc = minidom.parseString(xml)
         try:
             relax = False
@@ -114,14 +114,14 @@
         self.assertFalse(matches)
 
     def test_missing_uses_library(self):
-        xml = self.xml_tmpl % ('')
-        apk = self.apk_tmpl % ('')
+        xml = self.xml_tmpl % ''
+        apk = self.apk_tmpl % ''
         matches = self.run_test(xml, apk, uses_libraries=['foo'])
         self.assertFalse(matches)
 
     def test_missing_optional_uses_library(self):
-        xml = self.xml_tmpl % ('')
-        apk = self.apk_tmpl % ('')
+        xml = self.xml_tmpl % ''
+        apk = self.apk_tmpl % ''
         matches = self.run_test(xml, apk, optional_uses_libraries=['foo'])
         self.assertFalse(matches)
 
@@ -234,6 +234,32 @@
             optional_uses_libraries=['//x/y/z:bar'])
         self.assertTrue(matches)
 
+    def test_multiple_applications(self):
+        xml = """<?xml version="1.0" encoding="utf-8"?>
+            <manifest xmlns:android="http://schemas.android.com/apk/res/android">
+                <application android:featureFlag="foo">
+                    <uses-library android:name="foo" />
+                    <uses-library android:name="bar" android:required="false" />
+                </application>
+                <application android:featureFlag="!foo">
+                    <uses-library android:name="foo" />
+                    <uses-library android:name="qux" android:required="false" />
+                </application>
+            </manifest>
+        """
+        apk = self.apk_tmpl % ('\n'.join([
+            uses_library_apk('foo'),
+            uses_library_apk('bar', required_apk(False)),
+            uses_library_apk('foo'),
+            uses_library_apk('qux', required_apk(False))
+        ]))
+        matches = self.run_test(
+            xml,
+            apk,
+            uses_libraries=['//x/y/z:foo'],
+            optional_uses_libraries=['//x/y/z:bar', '//x/y/z:qux'])
+        self.assertTrue(matches)
+
 
 class ExtractTargetSdkVersionTest(unittest.TestCase):
 
@@ -256,12 +282,12 @@
         "targetSdkVersion:'%s'\n"
         "uses-permission: name='android.permission.ACCESS_NETWORK_STATE'\n")
 
-    def test_targert_sdk_version_28(self):
+    def test_target_sdk_version_28(self):
         xml = self.xml_tmpl % '28'
         apk = self.apk_tmpl % '28'
         self.run_test(xml, apk, '28')
 
-    def test_targert_sdk_version_29(self):
+    def test_target_sdk_version_29(self):
         xml = self.xml_tmpl % '29'
         apk = self.apk_tmpl % '29'
         self.run_test(xml, apk, '29')
diff --git a/scripts/manifest_fixer.py b/scripts/manifest_fixer.py
index 58079aa..9847ad5 100755
--- a/scripts/manifest_fixer.py
+++ b/scripts/manifest_fixer.py
@@ -23,15 +23,7 @@
 from xml.dom import minidom
 
 
-from manifest import android_ns
-from manifest import compare_version_gt
-from manifest import ensure_manifest_android_ns
-from manifest import find_child_with_attribute
-from manifest import get_children_with_tag
-from manifest import get_indent
-from manifest import parse_manifest
-from manifest import write_xml
-
+from manifest import *
 
 def parse_args():
   """Parse commandline arguments."""
@@ -48,9 +40,9 @@
   parser.add_argument('--library', dest='library', action='store_true',
                       help='manifest is for a static library')
   parser.add_argument('--uses-library', dest='uses_libraries', action='append',
-                      help='specify additional <uses-library> tag to add. android:requred is set to true')
+                      help='specify additional <uses-library> tag to add. android:required is set to true')
   parser.add_argument('--optional-uses-library', dest='optional_uses_libraries', action='append',
-                      help='specify additional <uses-library> tag to add. android:requred is set to false')
+                      help='specify additional <uses-library> tag to add. android:required is set to false')
   parser.add_argument('--uses-non-sdk-api', dest='uses_non_sdk_api', action='store_true',
                       help='manifest is for a package built against the platform')
   parser.add_argument('--logging-parent', dest='logging_parent', default='',
@@ -91,47 +83,33 @@
 
   manifest = parse_manifest(doc)
 
-  # Get or insert the uses-sdk element
-  uses_sdk = get_children_with_tag(manifest, 'uses-sdk')
-  if len(uses_sdk) > 1:
-    raise RuntimeError('found multiple uses-sdk elements')
-  elif len(uses_sdk) == 1:
-    element = uses_sdk[0]
-  else:
-    element = doc.createElement('uses-sdk')
-    indent = get_indent(manifest.firstChild, 1)
-    manifest.insertBefore(element, manifest.firstChild)
-
-    # Insert an indent before uses-sdk to line it up with the indentation of the
-    # other children of the <manifest> tag.
-    manifest.insertBefore(doc.createTextNode(indent), manifest.firstChild)
-
-  # Get or insert the minSdkVersion attribute.  If it is already present, make
-  # sure it as least the requested value.
-  min_attr = element.getAttributeNodeNS(android_ns, 'minSdkVersion')
-  if min_attr is None:
-    min_attr = doc.createAttributeNS(android_ns, 'android:minSdkVersion')
-    min_attr.value = min_sdk_version
-    element.setAttributeNode(min_attr)
-  else:
-    if compare_version_gt(min_sdk_version, min_attr.value):
+  for uses_sdk in get_or_create_uses_sdks(doc, manifest):
+    # Get or insert the minSdkVersion attribute.  If it is already present, make
+    # sure it as least the requested value.
+    min_attr = uses_sdk.getAttributeNodeNS(android_ns, 'minSdkVersion')
+    if min_attr is None:
+      min_attr = doc.createAttributeNS(android_ns, 'android:minSdkVersion')
       min_attr.value = min_sdk_version
-
-  # Insert the targetSdkVersion attribute if it is missing.  If it is already
-  # present leave it as is.
-  target_attr = element.getAttributeNodeNS(android_ns, 'targetSdkVersion')
-  if target_attr is None:
-    target_attr = doc.createAttributeNS(android_ns, 'android:targetSdkVersion')
-    if library:
-      # TODO(b/117122200): libraries shouldn't set targetSdkVersion at all, but
-      # ManifestMerger treats minSdkVersion="Q" as targetSdkVersion="Q" if it
-      # is empty.  Set it to something low so that it will be overriden by the
-      # main manifest, but high enough that it doesn't cause implicit
-      # permissions grants.
-      target_attr.value = '16'
+      uses_sdk.setAttributeNode(min_attr)
     else:
-      target_attr.value = target_sdk_version
-    element.setAttributeNode(target_attr)
+      if compare_version_gt(min_sdk_version, min_attr.value):
+        min_attr.value = min_sdk_version
+
+    # Insert the targetSdkVersion attribute if it is missing.  If it is already
+    # present leave it as is.
+    target_attr = uses_sdk.getAttributeNodeNS(android_ns, 'targetSdkVersion')
+    if target_attr is None:
+      target_attr = doc.createAttributeNS(android_ns, 'android:targetSdkVersion')
+      if library:
+        # TODO(b/117122200): libraries shouldn't set targetSdkVersion at all, but
+        # ManifestMerger treats minSdkVersion="Q" as targetSdkVersion="Q" if it
+        # is empty.  Set it to something low so that it will be overridden by the
+        # main manifest, but high enough that it doesn't cause implicit
+        # permissions grants.
+        target_attr.value = '16'
+      else:
+        target_attr.value = target_sdk_version
+      uses_sdk.setAttributeNode(target_attr)
 
 
 def add_logging_parent(doc, logging_parent_value):
@@ -147,37 +125,27 @@
   manifest = parse_manifest(doc)
 
   logging_parent_key = 'android.content.pm.LOGGING_PARENT'
-  elems = get_children_with_tag(manifest, 'application')
-  application = elems[0] if len(elems) == 1 else None
-  if len(elems) > 1:
-    raise RuntimeError('found multiple <application> tags')
-  elif not elems:
-    application = doc.createElement('application')
-    indent = get_indent(manifest.firstChild, 1)
-    first = manifest.firstChild
-    manifest.insertBefore(doc.createTextNode(indent), first)
-    manifest.insertBefore(application, first)
+  for application in get_or_create_applications(doc, manifest):
+    indent = get_indent(application.firstChild, 2)
 
-  indent = get_indent(application.firstChild, 2)
-
-  last = application.lastChild
-  if last is not None and last.nodeType != minidom.Node.TEXT_NODE:
-    last = None
-
-  if not find_child_with_attribute(application, 'meta-data', android_ns,
-                                   'name', logging_parent_key):
-    ul = doc.createElement('meta-data')
-    ul.setAttributeNS(android_ns, 'android:name', logging_parent_key)
-    ul.setAttributeNS(android_ns, 'android:value', logging_parent_value)
-    application.insertBefore(doc.createTextNode(indent), last)
-    application.insertBefore(ul, last)
     last = application.lastChild
+    if last is not None and last.nodeType != minidom.Node.TEXT_NODE:
+      last = None
 
-  # align the closing tag with the opening tag if it's not
-  # indented
-  if last and last.nodeType != minidom.Node.TEXT_NODE:
-    indent = get_indent(application.previousSibling, 1)
-    application.appendChild(doc.createTextNode(indent))
+    if not find_child_with_attribute(application, 'meta-data', android_ns,
+                                     'name', logging_parent_key):
+      ul = doc.createElement('meta-data')
+      ul.setAttributeNS(android_ns, 'android:name', logging_parent_key)
+      ul.setAttributeNS(android_ns, 'android:value', logging_parent_value)
+      application.insertBefore(doc.createTextNode(indent), last)
+      application.insertBefore(ul, last)
+      last = application.lastChild
+
+    # align the closing tag with the opening tag if it's not
+    # indented
+    if last and last.nodeType != minidom.Node.TEXT_NODE:
+      indent = get_indent(application.previousSibling, 1)
+      application.appendChild(doc.createTextNode(indent))
 
 
 def add_uses_libraries(doc, new_uses_libraries, required):
@@ -192,42 +160,32 @@
   """
 
   manifest = parse_manifest(doc)
-  elems = get_children_with_tag(manifest, 'application')
-  application = elems[0] if len(elems) == 1 else None
-  if len(elems) > 1:
-    raise RuntimeError('found multiple <application> tags')
-  elif not elems:
-    application = doc.createElement('application')
-    indent = get_indent(manifest.firstChild, 1)
-    first = manifest.firstChild
-    manifest.insertBefore(doc.createTextNode(indent), first)
-    manifest.insertBefore(application, first)
+  for application in get_or_create_applications(doc, manifest):
+    indent = get_indent(application.firstChild, 2)
 
-  indent = get_indent(application.firstChild, 2)
+    last = application.lastChild
+    if last is not None and last.nodeType != minidom.Node.TEXT_NODE:
+      last = None
 
-  last = application.lastChild
-  if last is not None and last.nodeType != minidom.Node.TEXT_NODE:
-    last = None
+    for name in new_uses_libraries:
+      if find_child_with_attribute(application, 'uses-library', android_ns,
+                                   'name', name) is not None:
+        # If the uses-library tag of the same 'name' attribute value exists,
+        # respect it.
+        continue
 
-  for name in new_uses_libraries:
-    if find_child_with_attribute(application, 'uses-library', android_ns,
-                                 'name', name) is not None:
-      # If the uses-library tag of the same 'name' attribute value exists,
-      # respect it.
-      continue
+      ul = doc.createElement('uses-library')
+      ul.setAttributeNS(android_ns, 'android:name', name)
+      ul.setAttributeNS(android_ns, 'android:required', str(required).lower())
 
-    ul = doc.createElement('uses-library')
-    ul.setAttributeNS(android_ns, 'android:name', name)
-    ul.setAttributeNS(android_ns, 'android:required', str(required).lower())
+      application.insertBefore(doc.createTextNode(indent), last)
+      application.insertBefore(ul, last)
 
-    application.insertBefore(doc.createTextNode(indent), last)
-    application.insertBefore(ul, last)
-
-  # align the closing tag with the opening tag if it's not
-  # indented
-  if application.lastChild.nodeType != minidom.Node.TEXT_NODE:
-    indent = get_indent(application.previousSibling, 1)
-    application.appendChild(doc.createTextNode(indent))
+    # align the closing tag with the opening tag if it's not
+    # indented
+    if application.lastChild.nodeType != minidom.Node.TEXT_NODE:
+      indent = get_indent(application.previousSibling, 1)
+      application.appendChild(doc.createTextNode(indent))
 
 
 def add_uses_non_sdk_api(doc):
@@ -240,111 +198,63 @@
   """
 
   manifest = parse_manifest(doc)
-  elems = get_children_with_tag(manifest, 'application')
-  application = elems[0] if len(elems) == 1 else None
-  if len(elems) > 1:
-    raise RuntimeError('found multiple <application> tags')
-  elif not elems:
-    application = doc.createElement('application')
-    indent = get_indent(manifest.firstChild, 1)
-    first = manifest.firstChild
-    manifest.insertBefore(doc.createTextNode(indent), first)
-    manifest.insertBefore(application, first)
-
-  attr = application.getAttributeNodeNS(android_ns, 'usesNonSdkApi')
-  if attr is None:
-    attr = doc.createAttributeNS(android_ns, 'android:usesNonSdkApi')
-    attr.value = 'true'
-    application.setAttributeNode(attr)
+  for application in get_or_create_applications(doc, manifest):
+    attr = application.getAttributeNodeNS(android_ns, 'usesNonSdkApi')
+    if attr is None:
+      attr = doc.createAttributeNS(android_ns, 'android:usesNonSdkApi')
+      attr.value = 'true'
+      application.setAttributeNode(attr)
 
 
 def add_use_embedded_dex(doc):
   manifest = parse_manifest(doc)
-  elems = get_children_with_tag(manifest, 'application')
-  application = elems[0] if len(elems) == 1 else None
-  if len(elems) > 1:
-    raise RuntimeError('found multiple <application> tags')
-  elif not elems:
-    application = doc.createElement('application')
-    indent = get_indent(manifest.firstChild, 1)
-    first = manifest.firstChild
-    manifest.insertBefore(doc.createTextNode(indent), first)
-    manifest.insertBefore(application, first)
-
-  attr = application.getAttributeNodeNS(android_ns, 'useEmbeddedDex')
-  if attr is None:
-    attr = doc.createAttributeNS(android_ns, 'android:useEmbeddedDex')
-    attr.value = 'true'
-    application.setAttributeNode(attr)
-  elif attr.value != 'true':
-    raise RuntimeError('existing attribute mismatches the option of --use-embedded-dex')
+  for application in get_or_create_applications(doc, manifest):
+    attr = application.getAttributeNodeNS(android_ns, 'useEmbeddedDex')
+    if attr is None:
+      attr = doc.createAttributeNS(android_ns, 'android:useEmbeddedDex')
+      attr.value = 'true'
+      application.setAttributeNode(attr)
+    elif attr.value != 'true':
+      raise RuntimeError('existing attribute mismatches the option of --use-embedded-dex')
 
 
 def add_extract_native_libs(doc, extract_native_libs):
   manifest = parse_manifest(doc)
-  elems = get_children_with_tag(manifest, 'application')
-  application = elems[0] if len(elems) == 1 else None
-  if len(elems) > 1:
-    raise RuntimeError('found multiple <application> tags')
-  elif not elems:
-    application = doc.createElement('application')
-    indent = get_indent(manifest.firstChild, 1)
-    first = manifest.firstChild
-    manifest.insertBefore(doc.createTextNode(indent), first)
-    manifest.insertBefore(application, first)
-
-  value = str(extract_native_libs).lower()
-  attr = application.getAttributeNodeNS(android_ns, 'extractNativeLibs')
-  if attr is None:
-    attr = doc.createAttributeNS(android_ns, 'android:extractNativeLibs')
-    attr.value = value
-    application.setAttributeNode(attr)
-  elif attr.value != value:
-    raise RuntimeError('existing attribute extractNativeLibs="%s" conflicts with --extract-native-libs="%s"' %
-                       (attr.value, value))
+  for application in get_or_create_applications(doc, manifest):
+    value = str(extract_native_libs).lower()
+    attr = application.getAttributeNodeNS(android_ns, 'extractNativeLibs')
+    if attr is None:
+      attr = doc.createAttributeNS(android_ns, 'android:extractNativeLibs')
+      attr.value = value
+      application.setAttributeNode(attr)
+    elif attr.value != value:
+      raise RuntimeError('existing attribute extractNativeLibs="%s" conflicts with --extract-native-libs="%s"' %
+                         (attr.value, value))
 
 
 def set_has_code_to_false(doc):
   manifest = parse_manifest(doc)
-  elems = get_children_with_tag(manifest, 'application')
-  application = elems[0] if len(elems) == 1 else None
-  if len(elems) > 1:
-    raise RuntimeError('found multiple <application> tags')
-  elif not elems:
-    application = doc.createElement('application')
-    indent = get_indent(manifest.firstChild, 1)
-    first = manifest.firstChild
-    manifest.insertBefore(doc.createTextNode(indent), first)
-    manifest.insertBefore(application, first)
+  for application in get_or_create_applications(doc, manifest):
+    attr = application.getAttributeNodeNS(android_ns, 'hasCode')
+    if attr is not None:
+      # Do nothing if the application already has a hasCode attribute.
+      continue
+    attr = doc.createAttributeNS(android_ns, 'android:hasCode')
+    attr.value = 'false'
+    application.setAttributeNode(attr)
 
-  attr = application.getAttributeNodeNS(android_ns, 'hasCode')
-  if attr is not None:
-    # Do nothing if the application already has a hasCode attribute.
-    return
-  attr = doc.createAttributeNS(android_ns, 'android:hasCode')
-  attr.value = 'false'
-  application.setAttributeNode(attr)
 
 def set_test_only_flag_to_true(doc):
   manifest = parse_manifest(doc)
-  elems = get_children_with_tag(manifest, 'application')
-  application = elems[0] if len(elems) == 1 else None
-  if len(elems) > 1:
-    raise RuntimeError('found multiple <application> tags')
-  elif not elems:
-    application = doc.createElement('application')
-    indent = get_indent(manifest.firstChild, 1)
-    first = manifest.firstChild
-    manifest.insertBefore(doc.createTextNode(indent), first)
-    manifest.insertBefore(application, first)
+  for application in get_or_create_applications(doc, manifest):
+    attr = application.getAttributeNodeNS(android_ns, 'testOnly')
+    if attr is not None:
+      # Do nothing If the application already has a testOnly attribute.
+      continue
+    attr = doc.createAttributeNS(android_ns, 'android:testOnly')
+    attr.value = 'true'
+    application.setAttributeNode(attr)
 
-  attr = application.getAttributeNodeNS(android_ns, 'testOnly')
-  if attr is not None:
-    # Do nothing If the application already has a testOnly attribute.
-    return
-  attr = doc.createAttributeNS(android_ns, 'android:testOnly')
-  attr.value = 'true'
-  application.setAttributeNode(attr)
 
 def set_max_sdk_version(doc, max_sdk_version):
   """Replace the maxSdkVersion attribute value for permission and
@@ -364,6 +274,7 @@
       if max_attr and max_attr.value == 'current':
         max_attr.value = max_sdk_version
 
+
 def override_placeholder_version(doc, new_version):
   """Replace the versionCode attribute value if it\'s currently
   set to the placeholder version of 0.
@@ -374,9 +285,10 @@
   """
   manifest = parse_manifest(doc)
   version = manifest.getAttribute("android:versionCode")
-  if (version == '0'):
+  if version == '0':
     manifest.setAttribute("android:versionCode", new_version)
 
+
 def main():
   """Program entry point."""
   try:
@@ -427,5 +339,6 @@
     print('error: ' + str(err), file=sys.stderr)
     sys.exit(-1)
 
+
 if __name__ == '__main__':
   main()
diff --git a/scripts/manifest_fixer_test.py b/scripts/manifest_fixer_test.py
index 0a62b10..e4d8dc3 100755
--- a/scripts/manifest_fixer_test.py
+++ b/scripts/manifest_fixer_test.py
@@ -20,12 +20,13 @@
 import sys
 import unittest
 from xml.dom import minidom
-import xml.etree.ElementTree as ET
+import xml.etree.ElementTree as ElementTree
 
 import manifest_fixer
 
 sys.dont_write_bytecode = True
 
+
 class CompareVersionGtTest(unittest.TestCase):
   """Unit tests for compare_version_gt function."""
 
@@ -69,25 +70,24 @@
       '%s'
       '</manifest>\n')
 
-  # pylint: disable=redefined-builtin
-  def uses_sdk(self, min=None, target=None, extra=''):
+  def uses_sdk(self, min_sdk=None, target_sdk=None, extra=''):
     attrs = ''
-    if min:
-      attrs += ' android:minSdkVersion="%s"' % (min)
-    if target:
-      attrs += ' android:targetSdkVersion="%s"' % (target)
+    if min_sdk:
+      attrs += ' android:minSdkVersion="%s"' % min_sdk
+    if target_sdk:
+      attrs += ' android:targetSdkVersion="%s"' % target_sdk
     if extra:
       attrs += ' ' + extra
-    return '    <uses-sdk%s/>\n' % (attrs)
+    return '    <uses-sdk%s/>\n' % attrs
 
   def assert_xml_equal(self, output, expected):
-    self.assertEqual(ET.canonicalize(output), ET.canonicalize(expected))
+    self.assertEqual(ElementTree.canonicalize(output), ElementTree.canonicalize(expected))
 
   def test_no_uses_sdk(self):
     """Tests inserting a uses-sdk element into a manifest."""
 
     manifest_input = self.manifest_tmpl % ''
-    expected = self.manifest_tmpl % self.uses_sdk(min='28', target='28')
+    expected = self.manifest_tmpl % self.uses_sdk(min_sdk='28', target_sdk='28')
     output = self.raise_min_sdk_version_test(manifest_input, '28', '28', False)
     self.assert_xml_equal(output, expected)
 
@@ -95,7 +95,7 @@
     """Tests inserting a minSdkVersion attribute into a uses-sdk element."""
 
     manifest_input = self.manifest_tmpl % '    <uses-sdk extra="foo"/>\n'
-    expected = self.manifest_tmpl % self.uses_sdk(min='28', target='28',
+    expected = self.manifest_tmpl % self.uses_sdk(min_sdk='28', target_sdk='28',
                                                   extra='extra="foo"')
     output = self.raise_min_sdk_version_test(manifest_input, '28', '28', False)
     self.assert_xml_equal(output, expected)
@@ -103,64 +103,64 @@
   def test_raise_min(self):
     """Tests inserting a minSdkVersion attribute into a uses-sdk element."""
 
-    manifest_input = self.manifest_tmpl % self.uses_sdk(min='27')
-    expected = self.manifest_tmpl % self.uses_sdk(min='28', target='28')
+    manifest_input = self.manifest_tmpl % self.uses_sdk(min_sdk='27')
+    expected = self.manifest_tmpl % self.uses_sdk(min_sdk='28', target_sdk='28')
     output = self.raise_min_sdk_version_test(manifest_input, '28', '28', False)
     self.assert_xml_equal(output, expected)
 
   def test_raise(self):
     """Tests raising a minSdkVersion attribute."""
 
-    manifest_input = self.manifest_tmpl % self.uses_sdk(min='27')
-    expected = self.manifest_tmpl % self.uses_sdk(min='28', target='28')
+    manifest_input = self.manifest_tmpl % self.uses_sdk(min_sdk='27')
+    expected = self.manifest_tmpl % self.uses_sdk(min_sdk='28', target_sdk='28')
     output = self.raise_min_sdk_version_test(manifest_input, '28', '28', False)
     self.assert_xml_equal(output, expected)
 
   def test_no_raise_min(self):
     """Tests a minSdkVersion that doesn't need raising."""
 
-    manifest_input = self.manifest_tmpl % self.uses_sdk(min='28')
-    expected = self.manifest_tmpl % self.uses_sdk(min='28', target='27')
+    manifest_input = self.manifest_tmpl % self.uses_sdk(min_sdk='28')
+    expected = self.manifest_tmpl % self.uses_sdk(min_sdk='28', target_sdk='27')
     output = self.raise_min_sdk_version_test(manifest_input, '27', '27', False)
     self.assert_xml_equal(output, expected)
 
   def test_raise_codename(self):
     """Tests raising a minSdkVersion attribute to a codename."""
 
-    manifest_input = self.manifest_tmpl % self.uses_sdk(min='28')
-    expected = self.manifest_tmpl % self.uses_sdk(min='P', target='P')
+    manifest_input = self.manifest_tmpl % self.uses_sdk(min_sdk='28')
+    expected = self.manifest_tmpl % self.uses_sdk(min_sdk='P', target_sdk='P')
     output = self.raise_min_sdk_version_test(manifest_input, 'P', 'P', False)
     self.assert_xml_equal(output, expected)
 
   def test_no_raise_codename(self):
     """Tests a minSdkVersion codename that doesn't need raising."""
 
-    manifest_input = self.manifest_tmpl % self.uses_sdk(min='P')
-    expected = self.manifest_tmpl % self.uses_sdk(min='P', target='28')
+    manifest_input = self.manifest_tmpl % self.uses_sdk(min_sdk='P')
+    expected = self.manifest_tmpl % self.uses_sdk(min_sdk='P', target_sdk='28')
     output = self.raise_min_sdk_version_test(manifest_input, '28', '28', False)
     self.assert_xml_equal(output, expected)
 
   def test_target(self):
     """Tests an existing targetSdkVersion is preserved."""
 
-    manifest_input = self.manifest_tmpl % self.uses_sdk(min='26', target='27')
-    expected = self.manifest_tmpl % self.uses_sdk(min='28', target='27')
+    manifest_input = self.manifest_tmpl % self.uses_sdk(min_sdk='26', target_sdk='27')
+    expected = self.manifest_tmpl % self.uses_sdk(min_sdk='28', target_sdk='27')
     output = self.raise_min_sdk_version_test(manifest_input, '28', '29', False)
     self.assert_xml_equal(output, expected)
 
   def test_no_target(self):
     """Tests inserting targetSdkVersion when minSdkVersion exists."""
 
-    manifest_input = self.manifest_tmpl % self.uses_sdk(min='27')
-    expected = self.manifest_tmpl % self.uses_sdk(min='28', target='29')
+    manifest_input = self.manifest_tmpl % self.uses_sdk(min_sdk='27')
+    expected = self.manifest_tmpl % self.uses_sdk(min_sdk='28', target_sdk='29')
     output = self.raise_min_sdk_version_test(manifest_input, '28', '29', False)
     self.assert_xml_equal(output, expected)
 
   def test_target_no_min(self):
     """"Tests inserting targetSdkVersion when minSdkVersion exists."""
 
-    manifest_input = self.manifest_tmpl % self.uses_sdk(target='27')
-    expected = self.manifest_tmpl % self.uses_sdk(min='28', target='27')
+    manifest_input = self.manifest_tmpl % self.uses_sdk(target_sdk='27')
+    expected = self.manifest_tmpl % self.uses_sdk(min_sdk='28', target_sdk='27')
     output = self.raise_min_sdk_version_test(manifest_input, '28', '29', False)
     self.assert_xml_equal(output, expected)
 
@@ -168,23 +168,23 @@
     """Tests inserting targetSdkVersion when minSdkVersion does not exist."""
 
     manifest_input = self.manifest_tmpl % ''
-    expected = self.manifest_tmpl % self.uses_sdk(min='28', target='29')
+    expected = self.manifest_tmpl % self.uses_sdk(min_sdk='28', target_sdk='29')
     output = self.raise_min_sdk_version_test(manifest_input, '28', '29', False)
     self.assert_xml_equal(output, expected)
 
   def test_library_no_target(self):
     """Tests inserting targetSdkVersion when minSdkVersion exists."""
 
-    manifest_input = self.manifest_tmpl % self.uses_sdk(min='27')
-    expected = self.manifest_tmpl % self.uses_sdk(min='28', target='16')
+    manifest_input = self.manifest_tmpl % self.uses_sdk(min_sdk='27')
+    expected = self.manifest_tmpl % self.uses_sdk(min_sdk='28', target_sdk='16')
     output = self.raise_min_sdk_version_test(manifest_input, '28', '29', True)
     self.assert_xml_equal(output, expected)
 
   def test_library_target_no_min(self):
     """Tests inserting targetSdkVersion when minSdkVersion exists."""
 
-    manifest_input = self.manifest_tmpl % self.uses_sdk(target='27')
-    expected = self.manifest_tmpl % self.uses_sdk(min='28', target='27')
+    manifest_input = self.manifest_tmpl % self.uses_sdk(target_sdk='27')
+    expected = self.manifest_tmpl % self.uses_sdk(min_sdk='28', target_sdk='27')
     output = self.raise_min_sdk_version_test(manifest_input, '28', '29', True)
     self.assert_xml_equal(output, expected)
 
@@ -192,7 +192,7 @@
     """Tests inserting targetSdkVersion when minSdkVersion does not exist."""
 
     manifest_input = self.manifest_tmpl % ''
-    expected = self.manifest_tmpl % self.uses_sdk(min='28', target='16')
+    expected = self.manifest_tmpl % self.uses_sdk(min_sdk='28', target_sdk='16')
     output = self.raise_min_sdk_version_test(manifest_input, '28', '29', True)
     self.assert_xml_equal(output, expected)
 
@@ -228,12 +228,24 @@
 
     self.assert_xml_equal(output, expected)
 
+  def test_multiple_uses_sdks(self):
+    """Tests a manifest that contains multiple uses_sdks elements."""
+
+    manifest_input = self.manifest_tmpl % (
+        '    <uses-sdk android:featureFlag="foo" android:minSdkVersion="21" />\n'
+        '    <uses-sdk android:featureFlag="!foo" android:minSdkVersion="22" />\n')
+    expected = self.manifest_tmpl % (
+      '    <uses-sdk android:featureFlag="foo" android:minSdkVersion="28" android:targetSdkVersion="28" />\n'
+      '    <uses-sdk android:featureFlag="!foo" android:minSdkVersion="28" android:targetSdkVersion="28" />\n')
+
+    output = self.raise_min_sdk_version_test(manifest_input, '28', '28', False)
+    self.assert_xml_equal(output, expected)
 
 class AddLoggingParentTest(unittest.TestCase):
   """Unit tests for add_logging_parent function."""
 
   def assert_xml_equal(self, output, expected):
-    self.assertEqual(ET.canonicalize(output), ET.canonicalize(expected))
+    self.assertEqual(ElementTree.canonicalize(output), ElementTree.canonicalize(expected))
 
   def add_logging_parent_test(self, input_manifest, logging_parent=None):
     doc = minidom.parseString(input_manifest)
@@ -253,8 +265,8 @@
     attrs = ''
     if logging_parent:
       meta_text = ('<meta-data android:name="android.content.pm.LOGGING_PARENT" '
-                   'android:value="%s"/>\n') % (logging_parent)
-      attrs += '    <application>\n        %s    </application>\n' % (meta_text)
+                   'android:value="%s"/>\n') % logging_parent
+      attrs += '    <application>\n        %s    </application>\n' % meta_text
 
     return attrs
 
@@ -277,7 +289,7 @@
   """Unit tests for add_uses_libraries function."""
 
   def assert_xml_equal(self, output, expected):
-    self.assertEqual(ET.canonicalize(output), ET.canonicalize(expected))
+    self.assertEqual(ElementTree.canonicalize(output), ElementTree.canonicalize(expected))
 
   def run_test(self, input_manifest, new_uses_libraries):
     doc = minidom.parseString(input_manifest)
@@ -289,18 +301,16 @@
   manifest_tmpl = (
       '<?xml version="1.0" encoding="utf-8"?>\n'
       '<manifest xmlns:android="http://schemas.android.com/apk/res/android">\n'
-      '    <application>\n'
       '%s'
-      '    </application>\n'
       '</manifest>\n')
 
   def uses_libraries(self, name_required_pairs):
-    ret = ''
+    ret = '    <application>\n'
     for name, required in name_required_pairs:
       ret += (
           '        <uses-library android:name="%s" android:required="%s"/>\n'
       ) % (name, required)
-
+    ret += '    </application>\n'
     return ret
 
   def test_empty(self):
@@ -361,12 +371,23 @@
     output = self.run_test(manifest_input, ['foo', 'bar'])
     self.assert_xml_equal(output, expected)
 
+  def test_multiple_application(self):
+    """When there are multiple applications, the libs are added to each."""
+    manifest_input = self.manifest_tmpl % (
+            self.uses_libraries([('foo', 'false')]) +
+            self.uses_libraries([('bar', 'false')]))
+    expected = self.manifest_tmpl % (
+            self.uses_libraries([('foo', 'false'), ('bar', 'true')]) +
+            self.uses_libraries([('bar', 'false'), ('foo', 'true')]))
+    output = self.run_test(manifest_input, ['foo', 'bar'])
+    self.assert_xml_equal(output, expected)
+
 
 class AddUsesNonSdkApiTest(unittest.TestCase):
   """Unit tests for add_uses_libraries function."""
 
   def assert_xml_equal(self, output, expected):
-    self.assertEqual(ET.canonicalize(output), ET.canonicalize(expected))
+    self.assertEqual(ElementTree.canonicalize(output), ElementTree.canonicalize(expected))
 
   def run_test(self, input_manifest):
     doc = minidom.parseString(input_manifest)
@@ -378,11 +399,11 @@
   manifest_tmpl = (
       '<?xml version="1.0" encoding="utf-8"?>\n'
       '<manifest xmlns:android="http://schemas.android.com/apk/res/android">\n'
-      '    <application%s/>\n'
+      '    %s\n'
       '</manifest>\n')
 
   def uses_non_sdk_api(self, value):
-    return ' android:usesNonSdkApi="true"' if value else ''
+    return '<application %s/>' % ('android:usesNonSdkApi="true"' if value else '')
 
   def test_set_true(self):
     """Empty new_uses_libraries must not touch the manifest."""
@@ -398,12 +419,19 @@
     output = self.run_test(manifest_input)
     self.assert_xml_equal(output, expected)
 
+  def test_multiple_applications(self):
+    """new_uses_libraries must be added to all applications."""
+    manifest_input = self.manifest_tmpl % (self.uses_non_sdk_api(True) +  self.uses_non_sdk_api(False))
+    expected = self.manifest_tmpl % (self.uses_non_sdk_api(True) +  self.uses_non_sdk_api(True))
+    output = self.run_test(manifest_input)
+    self.assert_xml_equal(output, expected)
+
 
 class UseEmbeddedDexTest(unittest.TestCase):
   """Unit tests for add_use_embedded_dex function."""
 
   def assert_xml_equal(self, output, expected):
-    self.assertEqual(ET.canonicalize(output), ET.canonicalize(expected))
+    self.assertEqual(ElementTree.canonicalize(output), ElementTree.canonicalize(expected))
 
   def run_test(self, input_manifest):
     doc = minidom.parseString(input_manifest)
@@ -415,14 +443,14 @@
   manifest_tmpl = (
       '<?xml version="1.0" encoding="utf-8"?>\n'
       '<manifest xmlns:android="http://schemas.android.com/apk/res/android">\n'
-      '    <application%s/>\n'
+      '    %s\n'
       '</manifest>\n')
 
   def use_embedded_dex(self, value):
-    return ' android:useEmbeddedDex="%s"' % value
+    return '<application android:useEmbeddedDex="%s" />' % value
 
   def test_manifest_with_undeclared_preference(self):
-    manifest_input = self.manifest_tmpl % ''
+    manifest_input = self.manifest_tmpl % '<application/>'
     expected = self.manifest_tmpl % self.use_embedded_dex('true')
     output = self.run_test(manifest_input)
     self.assert_xml_equal(output, expected)
@@ -437,12 +465,24 @@
     manifest_input = self.manifest_tmpl % self.use_embedded_dex('false')
     self.assertRaises(RuntimeError, self.run_test, manifest_input)
 
+  def test_multiple_applications(self):
+    manifest_input = self.manifest_tmpl % (
+        self.use_embedded_dex('true') +
+        '<application/>'
+    )
+    expected = self.manifest_tmpl % (
+        self.use_embedded_dex('true') +
+        self.use_embedded_dex('true')
+    )
+    output = self.run_test(manifest_input)
+    self.assert_xml_equal(output, expected)
+
 
 class AddExtractNativeLibsTest(unittest.TestCase):
   """Unit tests for add_extract_native_libs function."""
 
   def assert_xml_equal(self, output, expected):
-    self.assertEqual(ET.canonicalize(output), ET.canonicalize(expected))
+    self.assertEqual(ElementTree.canonicalize(output), ElementTree.canonicalize(expected))
 
   def run_test(self, input_manifest, value):
     doc = minidom.parseString(input_manifest)
@@ -454,20 +494,20 @@
   manifest_tmpl = (
       '<?xml version="1.0" encoding="utf-8"?>\n'
       '<manifest xmlns:android="http://schemas.android.com/apk/res/android">\n'
-      '    <application%s/>\n'
+      '    %s\n'
       '</manifest>\n')
 
   def extract_native_libs(self, value):
-    return ' android:extractNativeLibs="%s"' % value
+    return '<application android:extractNativeLibs="%s" />' % value
 
   def test_set_true(self):
-    manifest_input = self.manifest_tmpl % ''
+    manifest_input = self.manifest_tmpl % '<application/>'
     expected = self.manifest_tmpl % self.extract_native_libs('true')
     output = self.run_test(manifest_input, True)
     self.assert_xml_equal(output, expected)
 
   def test_set_false(self):
-    manifest_input = self.manifest_tmpl % ''
+    manifest_input = self.manifest_tmpl % '<application/>'
     expected = self.manifest_tmpl % self.extract_native_libs('false')
     output = self.run_test(manifest_input, False)
     self.assert_xml_equal(output, expected)
@@ -482,12 +522,18 @@
     manifest_input = self.manifest_tmpl % self.extract_native_libs('true')
     self.assertRaises(RuntimeError, self.run_test, manifest_input, False)
 
+  def test_multiple_applications(self):
+    manifest_input = self.manifest_tmpl % (self.extract_native_libs('true') + '<application/>')
+    expected = self.manifest_tmpl % (self.extract_native_libs('true') + self.extract_native_libs('true'))
+    output = self.run_test(manifest_input, True)
+    self.assert_xml_equal(output, expected)
+
 
 class AddNoCodeApplicationTest(unittest.TestCase):
   """Unit tests for set_has_code_to_false function."""
 
   def assert_xml_equal(self, output, expected):
-    self.assertEqual(ET.canonicalize(output), ET.canonicalize(expected))
+    self.assertEqual(ElementTree.canonicalize(output), ElementTree.canonicalize(expected))
 
   def run_test(self, input_manifest):
     doc = minidom.parseString(input_manifest)
@@ -515,7 +561,7 @@
     self.assert_xml_equal(output, expected)
 
   def test_has_application_has_code_false(self):
-    """ Do nothing if there's already an application elemeent. """
+    """ Do nothing if there's already an application element. """
     manifest_input = self.manifest_tmpl % '    <application android:hasCode="false"/>\n'
     output = self.run_test(manifest_input)
     self.assert_xml_equal(output, manifest_input)
@@ -527,12 +573,25 @@
     output = self.run_test(manifest_input)
     self.assert_xml_equal(output, manifest_input)
 
+  def test_multiple_applications(self):
+    """ Apply to all applications  """
+    manifest_input = self.manifest_tmpl % (
+        '    <application android:hasCode="true" />\n' +
+        '    <application android:hasCode="false" />\n' +
+        '    <application/>\n')
+    expected = self.manifest_tmpl % (
+        '    <application android:hasCode="true" />\n' +
+        '    <application android:hasCode="false" />\n' +
+        '    <application android:hasCode="false" />\n')
+    output = self.run_test(manifest_input)
+    self.assert_xml_equal(output, expected)
+
 
 class AddTestOnlyApplicationTest(unittest.TestCase):
   """Unit tests for set_test_only_flag_to_true function."""
 
   def assert_xml_equal(self, output, expected):
-    self.assertEqual(ET.canonicalize(output), ET.canonicalize(expected))
+    self.assertEqual(ElementTree.canonicalize(output), ElementTree.canonicalize(expected))
 
   def run_test(self, input_manifest):
     doc = minidom.parseString(input_manifest)
@@ -571,12 +630,26 @@
     output = self.run_test(manifest_input)
     self.assert_xml_equal(output, manifest_input)
 
+  def test_multiple_applications(self):
+    manifest_input = self.manifest_tmpl % (
+        '    <application android:testOnly="true" />\n' +
+        '    <application android:testOnly="false" />\n' +
+        '    <application/>\n'
+    )
+    expected = self.manifest_tmpl % (
+        '    <application android:testOnly="true" />\n' +
+        '    <application android:testOnly="false" />\n' +
+        '    <application android:testOnly="true" />\n'
+    )
+    output = self.run_test(manifest_input)
+    self.assert_xml_equal(output, expected)
+
 
 class SetMaxSdkVersionTest(unittest.TestCase):
   """Unit tests for set_max_sdk_version function."""
 
   def assert_xml_equal(self, output, expected):
-    self.assertEqual(ET.canonicalize(output), ET.canonicalize(expected))
+    self.assertEqual(ElementTree.canonicalize(output), ElementTree.canonicalize(expected))
 
   def run_test(self, input_manifest, max_sdk_version):
     doc = minidom.parseString(input_manifest)
@@ -591,15 +664,15 @@
       '%s'
       '</manifest>\n')
 
-  def permission(self, max=None):
-    if max is None:
+  def permission(self, max_sdk=None):
+    if max_sdk is None:
       return '   <permission/>'
-    return '    <permission android:maxSdkVersion="%s"/>\n' % max
+    return '    <permission android:maxSdkVersion="%s"/>\n' % max_sdk
 
-  def uses_permission(self, max=None):
-    if max is None:
+  def uses_permission(self, max_sdk=None):
+    if max_sdk is None:
       return '   <uses-permission/>'
-    return '    <uses-permission android:maxSdkVersion="%s"/>\n' % max
+    return '    <uses-permission android:maxSdkVersion="%s"/>\n' % max_sdk
 
   def test_permission_no_max_sdk_version(self):
     """Tests if permission has no maxSdkVersion attribute"""
@@ -643,11 +716,12 @@
     output = self.run_test(manifest_input, '9000')
     self.assert_xml_equal(output, expected)
 
+
 class OverrideDefaultVersionTest(unittest.TestCase):
   """Unit tests for override_default_version function."""
 
   def assert_xml_equal(self, output, expected):
-    self.assertEqual(ET.canonicalize(output), ET.canonicalize(expected))
+    self.assertEqual(ElementTree.canonicalize(output), ElementTree.canonicalize(expected))
 
   def run_test(self, input_manifest, version):
     doc = minidom.parseString(input_manifest)
diff --git a/ui/build/config.go b/ui/build/config.go
index f02222e..851a22a 100644
--- a/ui/build/config.go
+++ b/ui/build/config.go
@@ -54,6 +54,16 @@
 	rbeRandPrefix = rand.Intn(1000)
 }
 
+// Which builder are we using?
+type ninjaCommandType = int
+
+const (
+	_ = iota
+	NINJA_NINJA
+	NINJA_N2
+	NINJA_SISO
+)
+
 type Config struct{ *configImpl }
 
 type configImpl struct {
@@ -123,9 +133,8 @@
 	// could consider merging them.
 	moduleDebugFile string
 
-	// Whether to use n2 instead of ninja.  This is controlled with the
-	// environment variable SOONG_USE_N2
-	useN2 bool
+	// Which builder are we using
+	ninjaCommand ninjaCommandType
 }
 
 type NinjaWeightListSource uint
@@ -288,8 +297,16 @@
 		ret.moduleDebugFile, _ = filepath.Abs(shared.JoinPath(ret.SoongOutDir(), "soong-debug-info.json"))
 	}
 
-	if os.Getenv("SOONG_USE_N2") == "true" {
-		ret.useN2 = true
+	ret.ninjaCommand = NINJA_NINJA
+	switch os.Getenv("SOONG_NINJA") {
+	case "n2":
+		ret.ninjaCommand = NINJA_N2
+	case "siso":
+		ret.ninjaCommand = NINJA_SISO
+	default:
+		if os.Getenv("SOONG_USE_N2") == "true" {
+			ret.ninjaCommand = NINJA_N2
+		}
 	}
 
 	ret.environ.Unset(
@@ -349,7 +366,8 @@
 		// We read it here already, don't let others share in the fun
 		"GENERATE_SOONG_DEBUG",
 
-		// Use config.useN2 instead.
+		// Use config.ninjaCommand instead.
+		"SOONG_NINJA",
 		"SOONG_USE_N2",
 	)
 
@@ -1375,8 +1393,10 @@
 	// Perform a log directory cleanup only when the log directory
 	// is auto created by the build rather than user-specified.
 	for _, f := range []string{"RBE_proxy_log_dir", "FLAG_output_dir"} {
-		if _, ok := c.environ.Get(f); ok {
-			return false
+		if v, ok := c.environ.Get(f); ok {
+			if v != c.rbeTmpDir() {
+				return false
+			}
 		}
 	}
 	return true
@@ -1641,6 +1661,12 @@
 	return strings.ReplaceAll(path, "/linux-x86/", "/linux_musl-x86/")
 }
 
+func (c *configImpl) SisoBin() string {
+	path := c.PrebuiltBuildTool("siso")
+	// Use musl instead of glibc because glibc on the build server is old and has bugs
+	return strings.ReplaceAll(path, "/linux-x86/", "/linux_musl-x86/")
+}
+
 func (c *configImpl) PrebuiltBuildTool(name string) string {
 	if v, ok := c.environ.Get("SANITIZE_HOST"); ok {
 		if sanitize := strings.Fields(v); inList("address", sanitize) {
diff --git a/ui/build/ninja.go b/ui/build/ninja.go
index 4e3e544..def0783 100644
--- a/ui/build/ninja.go
+++ b/ui/build/ninja.go
@@ -49,14 +49,10 @@
 	nr := status.NewNinjaReader(ctx, ctx.Status.StartTool(), fifo)
 	defer nr.Close()
 
-	executable := config.NinjaBin()
-	args := []string{
-		"-d", "keepdepfile",
-		"-d", "keeprsp",
-		"-d", "stats",
-		"--frontend_file", fifo,
-	}
-	if config.useN2 {
+	var executable string
+	var args []string
+	switch config.ninjaCommand {
+	case NINJA_N2:
 		executable = config.N2Bin()
 		args = []string{
 			"-d", "trace",
@@ -66,8 +62,31 @@
 			//"-d", "stats",
 			"--frontend-file", fifo,
 		}
+	case NINJA_SISO:
+		executable = config.SisoBin()
+		args = []string{
+			"ninja",
+			"--log_dir", config.SoongOutDir(),
+			// TODO: implement these features, or remove them.
+			//"-d", "trace",
+			//"-d", "keepdepfile",
+			//"-d", "keeprsp",
+			//"-d", "stats",
+			//"--frontend-file", fifo,
+		}
+	default:
+		// NINJA_NINJA is the default.
+		executable = config.NinjaBin()
+		args = []string{
+			"-d", "keepdepfile",
+			"-d", "keeprsp",
+			"-d", "stats",
+			"--frontend_file", fifo,
+			"-o", "usesphonyoutputs=yes",
+			"-w", "dupbuild=err",
+			"-w", "missingdepfile=err",
+		}
 	}
-
 	args = append(args, config.NinjaArgs()...)
 
 	var parallel int
@@ -83,17 +102,10 @@
 
 	args = append(args, "-f", config.CombinedNinjaFile())
 
-	if !config.useN2 {
-		args = append(args,
-			"-o", "usesphonyoutputs=yes",
-			"-w", "dupbuild=err",
-			"-w", "missingdepfile=err")
-	}
-
 	if !config.BuildBrokenMissingOutputs() {
 		// Missing outputs will be treated as errors.
 		// BUILD_BROKEN_MISSING_OUTPUTS can be used to bypass this check.
-		if !config.useN2 {
+		if config.ninjaCommand != NINJA_N2 {
 			args = append(args,
 				"-w", "missingoutfile=err",
 			)
@@ -110,21 +122,18 @@
 		cmd.Environment.AppendFromKati(config.KatiEnvFile())
 	}
 
-	switch config.NinjaWeightListSource() {
-	case NINJA_LOG:
-		if !config.useN2 {
+	// TODO(b/346806126): implement this for the other ninjaCommand values.
+	if config.ninjaCommand == NINJA_NINJA {
+		switch config.NinjaWeightListSource() {
+		case NINJA_LOG:
 			cmd.Args = append(cmd.Args, "-o", "usesninjalogasweightlist=yes")
-		}
-	case EVENLY_DISTRIBUTED:
-		// pass empty weight list means ninja considers every tasks's weight as 1(default value).
-		if !config.useN2 {
+		case EVENLY_DISTRIBUTED:
+			// pass empty weight list means ninja considers every tasks's weight as 1(default value).
 			cmd.Args = append(cmd.Args, "-o", "usesweightlist=/dev/null")
-		}
-	case EXTERNAL_FILE:
-		fallthrough
-	case HINT_FROM_SOONG:
-		// The weight list is already copied/generated.
-		if !config.useN2 {
+		case EXTERNAL_FILE:
+			fallthrough
+		case HINT_FROM_SOONG:
+			// The weight list is already copied/generated.
 			ninjaWeightListPath := filepath.Join(config.OutDir(), ninjaWeightListFileName)
 			cmd.Args = append(cmd.Args, "-o", "usesweightlist="+ninjaWeightListPath)
 		}
@@ -227,6 +236,8 @@
 			// We don't want this build broken flag to cause reanalysis, so allow it through to the
 			// actions.
 			"BUILD_BROKEN_INCORRECT_PARTITION_IMAGES",
+			// Do not do reanalysis just because we changed ninja commands.
+			"SOONG_NINJA",
 			"SOONG_USE_N2",
 			"RUST_BACKTRACE",
 			"RUST_LOG",
@@ -235,8 +246,11 @@
 
 	cmd.Environment.Set("DIST_DIR", config.DistDir())
 	cmd.Environment.Set("SHELL", "/bin/bash")
-	if config.useN2 {
+	switch config.ninjaCommand {
+	case NINJA_N2:
 		cmd.Environment.Set("RUST_BACKTRACE", "1")
+	default:
+		// Only set RUST_BACKTRACE for n2.
 	}
 
 	// Print the environment variables that Ninja is operating in.
diff --git a/ui/build/soong.go b/ui/build/soong.go
index 97bc997..eb51022 100644
--- a/ui/build/soong.go
+++ b/ui/build/soong.go
@@ -588,19 +588,11 @@
 		nr := status.NewNinjaReader(ctx, ctx.Status.StartTool(), fifo)
 		defer nr.Close()
 
-		ninjaArgs := []string{
-			"-d", "keepdepfile",
-			"-d", "stats",
-			"-o", "usesphonyoutputs=yes",
-			"-o", "preremoveoutputs=yes",
-			"-w", "dupbuild=err",
-			"-w", "outputdir=err",
-			"-w", "missingoutfile=err",
-			"-j", strconv.Itoa(config.Parallel()),
-			"--frontend_file", fifo,
-			"-f", filepath.Join(config.SoongOutDir(), "bootstrap.ninja"),
-		}
-		if config.useN2 {
+		var ninjaCmd string
+		var ninjaArgs []string
+		switch config.ninjaCommand {
+		case NINJA_N2:
+			ninjaCmd = config.N2Bin()
 			ninjaArgs = []string{
 				// TODO: implement these features, or remove them.
 				//"-d", "keepdepfile",
@@ -615,6 +607,39 @@
 				"--frontend-file", fifo,
 				"-f", filepath.Join(config.SoongOutDir(), "bootstrap.ninja"),
 			}
+		case NINJA_SISO:
+			ninjaCmd = config.SisoBin()
+			ninjaArgs = []string{
+				"ninja",
+				// TODO: implement these features, or remove them.
+				//"-d", "keepdepfile",
+				//"-d", "stats",
+				//"-o", "usesphonyoutputs=yes",
+				//"-o", "preremoveoutputs=yes",
+				//"-w", "dupbuild=err",
+				//"-w", "outputdir=err",
+				//"-w", "missingoutfile=err",
+				"-v",
+				"-j", strconv.Itoa(config.Parallel()),
+				//"--frontend-file", fifo,
+				"--log_dir", config.SoongOutDir(),
+				"-f", filepath.Join(config.SoongOutDir(), "bootstrap.ninja"),
+			}
+		default:
+			// NINJA_NINJA is the default.
+			ninjaCmd = config.NinjaBin()
+			ninjaArgs = []string{
+				"-d", "keepdepfile",
+				"-d", "stats",
+				"-o", "usesphonyoutputs=yes",
+				"-o", "preremoveoutputs=yes",
+				"-w", "dupbuild=err",
+				"-w", "outputdir=err",
+				"-w", "missingoutfile=err",
+				"-j", strconv.Itoa(config.Parallel()),
+				"--frontend_file", fifo,
+				"-f", filepath.Join(config.SoongOutDir(), "bootstrap.ninja"),
+			}
 		}
 
 		if extra, ok := config.Environment().Get("SOONG_UI_NINJA_ARGS"); ok {
@@ -623,10 +648,6 @@
 		}
 
 		ninjaArgs = append(ninjaArgs, targets...)
-		ninjaCmd := config.NinjaBin()
-		if config.useN2 {
-			ninjaCmd = config.N2Bin()
-		}
 
 		cmd := Command(ctx, config, "soong bootstrap",
 			ninjaCmd, ninjaArgs...)