Move android_library resource handling to Bazel's ResourceProcessorBusyBox

The R.Java files generated by aapt2 link --no-static-lib-packages cause scaling problems by combining all resources into every package listed in a dependencies' AndroidManifest.xml file. For SystemUI-core this results in 74 R.java files, each with 76k lines, and takes 20 seconds to compile in javac. Both AGP and Bazel have workarounds for this that avoid using the R.java files generated by aapt2, instead generating more efficient R.class files directly based on the R.txt file. Bazel uses the ResourceProcessorBusyBox tool that is already present in our tree to process the resources. Reuse the same tool in Soong to create the R.jar. The more efficient R.class files require modifiying source files that use incorrect packages to refer to resources. Ignore-AOSP-First: merge conflict Bug: 284023594 Test: TestAndroidResourceProcessor Change-Id: I026073b40dabcfdb10e5d7a52e9348205b0e9a66
2023-06-20 22:40:02 -07:00
parent 2c5ed9e9ec
commit 039d8dfb67
7 changed files with 486 additions and 62 deletions
--- a/java/aar.go
+++ b/java/aar.go
@@ -88,16 +88,28 @@ type aaptProperties struct {
 	// do not include AndroidManifest from dependent libraries
 	Dont_merge_manifests *bool

+	// If use_resource_processor is set, use Bazel's resource processor instead of aapt2 to generate R.class files.
+	// The resource processor produces more optimal R.class files that only list resources in the package of the
+	// library that provided them, as opposed to aapt2 which produces R.java files for every package containing
+	// every resource.  Using the resource processor can provide significant build time speedups, but requires
+	// fixing the module to use the correct package to reference each resource, and to avoid having any other
+	// libraries in the tree that use the same package name.  Defaults to false, but will default to true in the
+	// future.
+	Use_resource_processor *bool
+
 	// true if RRO is enforced for any of the dependent modules
 	RROEnforcedForDependent bool `blueprint:"mutated"`
 }

 type aapt struct {
 	aaptSrcJar                     android.Path
+	transitiveAaptRJars            android.Paths
+	transitiveAaptResourcePackages android.Paths
 	exportPackage                  android.Path
 	manifestPath                   android.Path
 	proguardOptionsFile            android.Path
 	rTxt                           android.Path
+	rJar                           android.Path
 	extraAaptPackagesFile          android.Path
 	mergedManifestFile             android.Path
 	noticeFile                     android.OptionalPath
@@ -139,6 +151,10 @@ func propagateRROEnforcementMutator(ctx android.TopDownMutatorContext) {
 	}
 }

+func (a *aapt) useResourceProcessorBusyBox() bool {
+	return BoolDefault(a.aaptProperties.Use_resource_processor, false)
+}
+
 func (a *aapt) ExportPackage() android.Path {
 	return a.exportPackage
 }
@@ -175,7 +191,6 @@ func (a *aapt) aapt2Flags(ctx android.ModuleContext, sdkContext android.SdkConte
 	// Flags specified in Android.bp
 	linkFlags = append(linkFlags, a.aaptProperties.Aaptflags...)

-	linkFlags = append(linkFlags, "--no-static-lib-packages")
 	linkFlags = append(linkFlags, "--enable-compact-entries")

 	// Find implicit or explicit asset and resource dirs
@@ -349,6 +364,19 @@ func (a *aapt) buildActions(ctx android.ModuleContext, sdkContext android.SdkCon
 		linkFlags = append(linkFlags, "--static-lib")
 	}

+	if a.isLibrary && a.useResourceProcessorBusyBox() {
+		// When building an android_library using ResourceProcessorBusyBox the resources are merged into
+		// package-res.apk with --merge-only, but --no-static-lib-packages is not used so that R.txt only
+		// contains resources from this library.
+		linkFlags = append(linkFlags, "--merge-only")
+	} else {
+		// When building and app or when building an android_library without ResourceProcessorBusyBox
+		// --no-static-lib-packages is used to put all the resources into the app.  If ResourceProcessorBusyBox
+		// is used then the app's R.txt will be post-processed along with the R.txt files from dependencies to
+		// sort resources into the right packages in R.class.
+		linkFlags = append(linkFlags, "--no-static-lib-packages")
+	}
+
 	packageRes := android.PathForModuleOut(ctx, "package-res.apk")
 	// the subdir "android" is required to be filtered by package names
 	srcJar := android.PathForModuleGen(ctx, "android", "R.srcjar")
@@ -356,6 +384,7 @@ func (a *aapt) buildActions(ctx android.ModuleContext, sdkContext android.SdkCon
 	rTxt := android.PathForModuleOut(ctx, "R.txt")
 	// This file isn't used by Soong, but is generated for exporting
 	extraPackages := android.PathForModuleOut(ctx, "extra_packages")
+	var transitiveRJars android.Paths

 	var compiledResDirs []android.Paths
 	for _, dir := range resDirs {
@@ -375,7 +404,23 @@ func (a *aapt) buildActions(ctx android.ModuleContext, sdkContext android.SdkCon
 	// of transitiveStaticLibs.
 	transitiveStaticLibs := android.ReversePaths(staticDeps.resPackages())

+	if a.isLibrary && a.useResourceProcessorBusyBox() {
+		// When building an android_library with ResourceProcessorBusyBox enabled treat static library dependencies
+		// as imports.  The resources from dependencies will not be merged into this module's package-res.apk, and
+		// instead modules depending on this module will reference package-res.apk from all transitive static
+		// dependencies.
+		for _, staticDep := range staticDeps {
+			linkDeps = append(linkDeps, staticDep.resPackage)
+			linkFlags = append(linkFlags, "-I "+staticDep.resPackage.String())
+			if staticDep.usedResourceProcessor {
+				transitiveRJars = append(transitiveRJars, staticDep.rJar)
+			}
+		}
+	} else {
+		// When building an app or building a library without ResourceProcessorBusyBox enabled all static
+		// dependencies are compiled into this module's package-res.apk as overlays.
 		compiledOverlay = append(compiledOverlay, transitiveStaticLibs...)
+	}

 	if len(transitiveStaticLibs) > 0 {
 		// If we are using static android libraries, every source file becomes an overlay.
@@ -438,7 +483,16 @@ func (a *aapt) buildActions(ctx android.ModuleContext, sdkContext android.SdkCon
 		a.assetPackage = android.OptionalPathForPath(assets)
 	}

+	if a.useResourceProcessorBusyBox() {
+		rJar := android.PathForModuleOut(ctx, "busybox/R.jar")
+		resourceProcessorBusyBoxGenerateBinaryR(ctx, rTxt, a.mergedManifestFile, rJar, staticDeps, a.isLibrary)
+		transitiveRJars = append(transitiveRJars, rJar)
+		a.rJar = rJar
+	}
+
 	a.aaptSrcJar = srcJar
+	a.transitiveAaptRJars = transitiveRJars
+	a.transitiveAaptResourcePackages = staticDeps.resPackages()
 	a.exportPackage = packageRes
 	a.manifestPath = manifestPath
 	a.proguardOptionsFile = proguardOptionsFile
@@ -450,7 +504,11 @@ func (a *aapt) buildActions(ctx android.ModuleContext, sdkContext android.SdkCon
 			resPackage:          a.exportPackage,
 			manifest:            a.manifestPath,
 			additionalManifests: additionalManifests,
+			rTxt:                a.rTxt,
+			rJar:                a.rJar,
 			assets:              a.assetPackage,
+
+			usedResourceProcessor: a.useResourceProcessorBusyBox(),
 		}).
 		Transitive(staticResourcesNodesDepSet).Build()
 	a.rroDirsDepSet = android.NewDepSetBuilder[rroDir](android.TOPOLOGICAL).
@@ -462,34 +520,93 @@ func (a *aapt) buildActions(ctx android.ModuleContext, sdkContext android.SdkCon
 		Transitive(staticManifestsDepSet).Build()
 }

+var resourceProcessorBusyBox = pctx.AndroidStaticRule("resourceProcessorBusyBox",
+	blueprint.RuleParams{
+		Command: "${config.JavaCmd} -cp ${config.ResourceProcessorBusyBox} " +
+			"com.google.devtools.build.android.ResourceProcessorBusyBox --tool=GENERATE_BINARY_R -- @${out}.args && " +
+			"if cmp -s ${out}.tmp ${out} ; then rm ${out}.tmp ; else mv ${out}.tmp ${out}; fi",
+		CommandDeps:    []string{"${config.ResourceProcessorBusyBox}"},
+		Rspfile:        "${out}.args",
+		RspfileContent: "--primaryRTxt ${rTxt} --primaryManifest ${manifest} --classJarOutput ${out}.tmp ${args}",
+		Restat:         true,
+	}, "rTxt", "manifest", "args")
+
+// resourceProcessorBusyBoxGenerateBinaryR converts the R.txt file produced by aapt2 into R.class files
+// using Bazel's ResourceProcessorBusyBox tool, which is faster than compiling the R.java files and
+// supports producing classes for static dependencies that only include resources from that dependency.
+func resourceProcessorBusyBoxGenerateBinaryR(ctx android.ModuleContext, rTxt, manifest android.Path,
+	rJar android.WritablePath, transitiveDeps transitiveAarDeps, isLibrary bool) {
+
+	var args []string
+	var deps android.Paths
+
+	if !isLibrary {
+		// When compiling an app, pass all R.txt and AndroidManifest.xml from transitive static library dependencies
+		// to ResourceProcessorBusyBox so that it can regenerate R.class files with the final resource IDs for each
+		// package.
+		args, deps = transitiveDeps.resourceProcessorDeps()
+	} else {
+		// When compiling a library don't pass any dependencies as it only needs to generate an R.class file for this
+		// library.  Pass --finalFields=false so that the R.class file contains non-final fields so they don't get
+		// inlined into the library before the final IDs are assigned during app compilation.
+		args = append(args, "--finalFields=false")
+	}
+
+	deps = append(deps, rTxt, manifest)
+
+	ctx.Build(pctx, android.BuildParams{
+		Rule:        resourceProcessorBusyBox,
+		Output:      rJar,
+		Implicits:   deps,
+		Description: "ResourceProcessorBusyBox",
+		Args: map[string]string{
+			"rTxt":     rTxt.String(),
+			"manifest": manifest.String(),
+			"args":     strings.Join(args, " "),
+		},
+	})
+}
+
 type resourcesNode struct {
 	resPackage          android.Path
 	manifest            android.Path
 	additionalManifests android.Paths
+	rTxt                android.Path
+	rJar                android.Path
 	assets              android.OptionalPath
+
+	usedResourceProcessor bool
 }

 type transitiveAarDeps []*resourcesNode

 func (t transitiveAarDeps) resPackages() android.Paths {
-	var paths android.Paths
+	paths := make(android.Paths, 0, len(t))
 	for _, dep := range t {
 		paths = append(paths, dep.resPackage)
 	}
-	return android.FirstUniquePaths(paths)
+	return paths
 }

 func (t transitiveAarDeps) manifests() android.Paths {
-	var paths android.Paths
+	paths := make(android.Paths, 0, len(t))
 	for _, dep := range t {
 		paths = append(paths, dep.manifest)
 		paths = append(paths, dep.additionalManifests...)
 	}
-	return android.FirstUniquePaths(paths)
+	return paths
+}
+
+func (t transitiveAarDeps) resourceProcessorDeps() (args []string, deps android.Paths) {
+	for _, dep := range t {
+		args = append(args, "--library="+dep.rTxt.String()+","+dep.manifest.String())
+		deps = append(deps, dep.rTxt, dep.manifest)
+	}
+	return args, deps
 }

 func (t transitiveAarDeps) assets() android.Paths {
-	var paths android.Paths
+	paths := make(android.Paths, 0, len(t))
 	for _, dep := range t {
 		if dep.assets.Valid() {
 			paths = append(paths, dep.assets.Path())
@@ -614,9 +731,12 @@ func (a *AndroidLibrary) GenerateAndroidBuildActions(ctx android.ModuleContext)

 	a.stem = proptools.StringDefault(a.overridableDeviceProperties.Stem, ctx.ModuleName())

-	ctx.CheckbuildFile(a.proguardOptionsFile)
-	ctx.CheckbuildFile(a.exportPackage)
-	ctx.CheckbuildFile(a.aaptSrcJar)
+	ctx.CheckbuildFile(a.aapt.proguardOptionsFile)
+	ctx.CheckbuildFile(a.aapt.exportPackage)
+	ctx.CheckbuildFile(a.aapt.aaptSrcJar)
+	if a.useResourceProcessorBusyBox() {
+		ctx.CheckbuildFile(a.aapt.rJar)
+	}

 	// apps manifests are handled by aapt, don't let Module see them
 	a.properties.Manifest = nil
@@ -628,7 +748,22 @@ func (a *AndroidLibrary) GenerateAndroidBuildActions(ctx android.ModuleContext)
 	a.Module.extraProguardFlagFiles = append(a.Module.extraProguardFlagFiles,
 		a.proguardOptionsFile)

-	a.Module.compile(ctx, a.aaptSrcJar)
+	var extraSrcJars android.Paths
+	var extraCombinedJars android.Paths
+	var extraClasspathJars android.Paths
+	if a.useResourceProcessorBusyBox() {
+		// When building a library with ResourceProcessorBusyBox enabled ResourceProcessorBusyBox for this
+		// library and each of the transitive static android_library dependencies has already created an
+		// R.class file for the appropriate package.  Add all of those R.class files to the classpath.
+		extraClasspathJars = a.transitiveAaptRJars
+	} else {
+		// When building a library without ResourceProcessorBusyBox the aapt2 rule creates R.srcjar containing
+		// R.java files for the library's package and the packages from all transitive static android_library
+		// dependencies.  Compile the srcjar alongside the rest of the sources.
+		extraSrcJars = android.Paths{a.aapt.aaptSrcJar}
+	}
+
+	a.Module.compile(ctx, extraSrcJars, extraClasspathJars, extraCombinedJars)

 	a.aarFile = android.PathForModuleOut(ctx, ctx.ModuleName()+".aar")
 	var res android.Paths
@@ -733,9 +868,12 @@ type AARImport struct {
 	classpathFile                  android.WritablePath
 	proguardFlags                  android.WritablePath
 	exportPackage                  android.WritablePath
+	transitiveAaptResourcePackages android.Paths
 	extraAaptPackagesFile          android.WritablePath
 	manifest                       android.WritablePath
 	assetsPackage                  android.WritablePath
+	rTxt                           android.WritablePath
+	rJar                           android.WritablePath

 	resourcesNodesDepSet *android.DepSet[*resourcesNode]
 	manifestsDepSet      *android.DepSet[android.Path]
@@ -904,12 +1042,13 @@ func (a *AARImport) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	a.classpathFile = extractedAARDir.Join(ctx, "classes-combined.jar")
 	a.proguardFlags = extractedAARDir.Join(ctx, "proguard.txt")
 	a.manifest = extractedAARDir.Join(ctx, "AndroidManifest.xml")
+	aarRTxt := extractedAARDir.Join(ctx, "R.txt")
 	a.assetsPackage = android.PathForModuleOut(ctx, "assets.zip")

 	ctx.Build(pctx, android.BuildParams{
 		Rule:        unzipAAR,
 		Input:       a.aarPath,
-		Outputs:     android.WritablePaths{a.classpathFile, a.proguardFlags, a.manifest, a.assetsPackage},
+		Outputs:     android.WritablePaths{a.classpathFile, a.proguardFlags, a.manifest, a.assetsPackage, aarRTxt},
 		Description: "unzip AAR",
 		Args: map[string]string{
 			"outDir":             extractedAARDir.String(),
@@ -929,14 +1068,14 @@ func (a *AARImport) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	// the subdir "android" is required to be filtered by package names
 	srcJar := android.PathForModuleGen(ctx, "android", "R.srcjar")
 	proguardOptionsFile := android.PathForModuleGen(ctx, "proguard.options")
-	rTxt := android.PathForModuleOut(ctx, "R.txt")
+	a.rTxt = android.PathForModuleOut(ctx, "R.txt")
 	a.extraAaptPackagesFile = android.PathForModuleOut(ctx, "extra_packages")

 	var linkDeps android.Paths

 	linkFlags := []string{
 		"--static-lib",
-		"--no-static-lib-packages",
+		"--merge-only",
 		"--auto-add-overlay",
 	}

@@ -949,25 +1088,35 @@ func (a *AARImport) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	_ = staticRRODirsDepSet
 	staticDeps := transitiveAarDeps(staticResourcesNodesDepSet.ToList())

-	// AAPT2 overlays are in lowest to highest priority order, reverse the topological order
-	// of transitiveStaticLibs.
-	transitiveStaticLibs := android.ReversePaths(staticDeps.resPackages())
-
 	linkDeps = append(linkDeps, sharedLibs...)
-	linkDeps = append(linkDeps, transitiveStaticLibs...)
+	linkDeps = append(linkDeps, staticDeps.resPackages()...)
 	linkFlags = append(linkFlags, libFlags...)

-	overlayRes := append(android.Paths{flata}, transitiveStaticLibs...)
+	overlayRes := android.Paths{flata}
+
+	// Treat static library dependencies of static libraries as imports.
+	transitiveStaticLibs := staticDeps.resPackages()
+	linkDeps = append(linkDeps, transitiveStaticLibs...)
+	for _, staticLib := range transitiveStaticLibs {
+		linkFlags = append(linkFlags, "-I "+staticLib.String())
+	}

 	transitiveAssets := android.ReverseSliceInPlace(staticDeps.assets())
-	aapt2Link(ctx, a.exportPackage, srcJar, proguardOptionsFile, rTxt, a.extraAaptPackagesFile,
+	aapt2Link(ctx, a.exportPackage, srcJar, proguardOptionsFile, a.rTxt, a.extraAaptPackagesFile,
 		linkFlags, linkDeps, nil, overlayRes, transitiveAssets, nil)

+	a.rJar = android.PathForModuleOut(ctx, "busybox/R.jar")
+	resourceProcessorBusyBoxGenerateBinaryR(ctx, a.rTxt, a.manifest, a.rJar, nil, true)
+
 	resourcesNodesDepSetBuilder := android.NewDepSetBuilder[*resourcesNode](android.TOPOLOGICAL)
 	resourcesNodesDepSetBuilder.Direct(&resourcesNode{
 		resPackage: a.exportPackage,
 		manifest:   a.manifest,
+		rTxt:       a.rTxt,
+		rJar:       a.rJar,
 		assets:     android.OptionalPathForPath(a.assetsPackage),
+
+		usedResourceProcessor: true,
 	})
 	resourcesNodesDepSetBuilder.Transitive(staticResourcesNodesDepSet)
 	a.resourcesNodesDepSet = resourcesNodesDepSetBuilder.Build()
@@ -982,6 +1131,8 @@ func (a *AARImport) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	_ = staticManifestsDepSet
 	a.manifestsDepSet = manifestDepSetBuilder.Build()

+	a.transitiveAaptResourcePackages = staticDeps.resPackages()
+
 	a.collectTransitiveHeaderJars(ctx)
 	ctx.SetProvider(JavaInfoProvider, JavaInfo{
 		HeaderJars:                     android.PathsIfNonNil(a.classpathFile),
--- a/java/androidmk.go
+++ b/java/androidmk.go
@@ -265,6 +265,7 @@ func (prebuilt *AARImport) AndroidMkEntries() []android.AndroidMkEntries {
 				entries.SetPath("LOCAL_SOONG_HEADER_JAR", prebuilt.classpathFile)
 				entries.SetPath("LOCAL_SOONG_CLASSES_JAR", prebuilt.classpathFile)
 				entries.SetPath("LOCAL_SOONG_RESOURCE_EXPORT_PACKAGE", prebuilt.exportPackage)
+				entries.SetPaths("LOCAL_SOONG_TRANSITIVE_RES_PACKAGES", prebuilt.transitiveAaptResourcePackages)
 				entries.SetPath("LOCAL_SOONG_EXPORT_PROGUARD_FLAGS", prebuilt.proguardFlags)
 				entries.SetPath("LOCAL_SOONG_STATIC_LIBRARY_EXTRA_PACKAGES", prebuilt.extraAaptPackagesFile)
 				entries.SetPath("LOCAL_FULL_MANIFEST_FILE", prebuilt.manifest)
@@ -508,6 +509,7 @@ func (a *AndroidLibrary) AndroidMkEntries() []android.AndroidMkEntries {
 		}

 		entries.SetPath("LOCAL_SOONG_RESOURCE_EXPORT_PACKAGE", a.exportPackage)
+		entries.SetPaths("LOCAL_SOONG_TRANSITIVE_RES_PACKAGES", a.transitiveAaptResourcePackages)
 		entries.SetPath("LOCAL_SOONG_STATIC_LIBRARY_EXTRA_PACKAGES", a.extraAaptPackagesFile)
 		entries.SetPath("LOCAL_FULL_MANIFEST_FILE", a.mergedManifestFile)
 		entries.AddStrings("LOCAL_SOONG_EXPORT_PROGUARD_FLAGS", a.exportedProguardFlagFiles.Strings()...)
--- a/java/app.go
+++ b/java/app.go
@@ -521,7 +521,23 @@ func (a *AndroidApp) dexBuildActions(ctx android.ModuleContext) android.Path {
 	a.dexpreopter.preventInstall = a.appProperties.PreventInstall

 	if ctx.ModuleName() != "framework-res" {
-		a.Module.compile(ctx, a.aaptSrcJar)
+		var extraSrcJars android.Paths
+		var extraClasspathJars android.Paths
+		var extraCombinedJars android.Paths
+		if a.useResourceProcessorBusyBox() {
+			// When building an app with ResourceProcessorBusyBox enabled ResourceProcessorBusyBox has already
+			// created R.class files that provide IDs for resources in busybox/R.jar.  Pass that file in the
+			// classpath when compiling everything else, and add it to the final classes jar.
+			extraClasspathJars = android.Paths{a.aapt.rJar}
+			extraCombinedJars = android.Paths{a.aapt.rJar}
+		} else {
+			// When building an app without ResourceProcessorBusyBox the aapt2 rule creates R.srcjar containing
+			// R.java files for the app's package and the packages from all transitive static android_library
+			// dependencies.  Compile the srcjar alongside the rest of the sources.
+			extraSrcJars = android.Paths{a.aapt.aaptSrcJar}
+		}
+
+		a.Module.compile(ctx, extraSrcJars, extraClasspathJars, extraCombinedJars)
 	}

 	return a.dexJarFile.PathOrNil()
--- a/java/app_test.go
+++ b/java/app_test.go
@@ -723,6 +723,9 @@ func TestAppJavaResources(t *testing.T) {
 func TestAndroidResourceProcessor(t *testing.T) {
 	testCases := []struct {
 		name                string
+		appUsesRP           bool
+		directLibUsesRP     bool
+		transitiveLibUsesRP bool

 		dontVerifyApp bool
 		appResources  []string
@@ -759,7 +762,12 @@ func TestAndroidResourceProcessor(t *testing.T) {
 		transitiveImportImports    []string
 	}{
 		{
+			// Test with all modules set to use_resource_processor: false (except android_library_import modules,
+			// which always use resource processor).
 			name:                "legacy",
+			appUsesRP:           false,
+			directLibUsesRP:     false,
+			transitiveLibUsesRP: false,

 			appResources: nil,
 			appOverlays: []string{
@@ -771,7 +779,6 @@ func TestAndroidResourceProcessor(t *testing.T) {
 				"out/soong/.intermediates/direct_import/android_common/package-res.apk",
 				"out/soong/.intermediates/app/android_common/aapt2/app/res/values_strings.arsc.flat",
 			},
-
 			appImports: []string{"out/soong/.intermediates/default/java/framework-res/android_common/package-res.apk"},
 			appSrcJars: []string{"out/soong/.intermediates/app/android_common/gen/android/R.srcjar"},
 			appClasspath: []string{
@@ -792,7 +799,6 @@ func TestAndroidResourceProcessor(t *testing.T) {
 				"out/soong/.intermediates/transitive_import/android_common/package-res.apk",
 				"out/soong/.intermediates/direct/android_common/aapt2/direct/res/values_strings.arsc.flat",
 			},
-
 			directImports: []string{"out/soong/.intermediates/default/java/framework-res/android_common/package-res.apk"},
 			directSrcJars: []string{"out/soong/.intermediates/direct/android_common/gen/android/R.srcjar"},
 			directClasspath: []string{
@@ -814,18 +820,256 @@ func TestAndroidResourceProcessor(t *testing.T) {
 			transitiveCombined:  nil,

 			directImportResources: nil,
-			directImportOverlays: []string{
-				"out/soong/.intermediates/direct_import/android_common/flat-res/gen_res.flata",
+			directImportOverlays:  []string{"out/soong/.intermediates/direct_import/android_common/flat-res/gen_res.flata"},
+			directImportImports: []string{
+				"out/soong/.intermediates/default/java/framework-res/android_common/package-res.apk",
 				"out/soong/.intermediates/direct_import_dep/android_common/package-res.apk",
 			},
-			directImportImports: []string{"out/soong/.intermediates/default/java/framework-res/android_common/package-res.apk"},

 			transitiveImportResources: nil,
-			transitiveImportOverlays: []string{
-				"out/soong/.intermediates/transitive_import/android_common/flat-res/gen_res.flata",
+			transitiveImportOverlays:  []string{"out/soong/.intermediates/transitive_import/android_common/flat-res/gen_res.flata"},
+			transitiveImportImports: []string{
+				"out/soong/.intermediates/default/java/framework-res/android_common/package-res.apk",
 				"out/soong/.intermediates/transitive_import_dep/android_common/package-res.apk",
 			},
-			transitiveImportImports: []string{"out/soong/.intermediates/default/java/framework-res/android_common/package-res.apk"},
+		},
+		{
+			// Test with all modules set to use_resource_processor: true.
+			name:                "resource_processor",
+			appUsesRP:           true,
+			directLibUsesRP:     true,
+			transitiveLibUsesRP: true,
+
+			appResources: nil,
+			appOverlays: []string{
+				"out/soong/.intermediates/transitive/android_common/package-res.apk",
+				"out/soong/.intermediates/transitive_import_dep/android_common/package-res.apk",
+				"out/soong/.intermediates/transitive_import/android_common/package-res.apk",
+				"out/soong/.intermediates/direct/android_common/package-res.apk",
+				"out/soong/.intermediates/direct_import_dep/android_common/package-res.apk",
+				"out/soong/.intermediates/direct_import/android_common/package-res.apk",
+				"out/soong/.intermediates/app/android_common/aapt2/app/res/values_strings.arsc.flat",
+			},
+			appImports: []string{"out/soong/.intermediates/default/java/framework-res/android_common/package-res.apk"},
+			appSrcJars: nil,
+			appClasspath: []string{
+				"out/soong/.intermediates/default/java/android_stubs_current/android_common/turbine-combined/android_stubs_current.jar",
+				"out/soong/.intermediates/app/android_common/busybox/R.jar",
+				"out/soong/.intermediates/direct/android_common/turbine-combined/direct.jar",
+				"out/soong/.intermediates/direct_import/android_common/aar/classes-combined.jar",
+			},
+			appCombined: []string{
+				"out/soong/.intermediates/app/android_common/busybox/R.jar",
+				"out/soong/.intermediates/app/android_common/javac/app.jar",
+				"out/soong/.intermediates/direct/android_common/combined/direct.jar",
+				"out/soong/.intermediates/direct_import/android_common/aar/classes-combined.jar",
+			},
+
+			directResources: nil,
+			directOverlays:  []string{"out/soong/.intermediates/direct/android_common/aapt2/direct/res/values_strings.arsc.flat"},
+			directImports: []string{
+				"out/soong/.intermediates/default/java/framework-res/android_common/package-res.apk",
+				"out/soong/.intermediates/transitive_import/android_common/package-res.apk",
+				"out/soong/.intermediates/transitive_import_dep/android_common/package-res.apk",
+				"out/soong/.intermediates/transitive/android_common/package-res.apk",
+			},
+			directSrcJars: nil,
+			directClasspath: []string{
+				"out/soong/.intermediates/default/java/android_stubs_current/android_common/turbine-combined/android_stubs_current.jar",
+				"out/soong/.intermediates/transitive_import/android_common/busybox/R.jar",
+				"out/soong/.intermediates/transitive_import_dep/android_common/busybox/R.jar",
+				"out/soong/.intermediates/transitive/android_common/busybox/R.jar",
+				"out/soong/.intermediates/direct/android_common/busybox/R.jar",
+				"out/soong/.intermediates/transitive/android_common/turbine-combined/transitive.jar",
+				"out/soong/.intermediates/transitive_import/android_common/aar/classes-combined.jar",
+			},
+			directCombined: []string{
+				"out/soong/.intermediates/direct/android_common/javac/direct.jar",
+				"out/soong/.intermediates/transitive/android_common/javac/transitive.jar",
+				"out/soong/.intermediates/transitive_import/android_common/aar/classes-combined.jar",
+			},
+
+			transitiveResources: []string{"out/soong/.intermediates/transitive/android_common/aapt2/transitive/res/values_strings.arsc.flat"},
+			transitiveOverlays:  nil,
+			transitiveImports:   []string{"out/soong/.intermediates/default/java/framework-res/android_common/package-res.apk"},
+			transitiveSrcJars:   nil,
+			transitiveClasspath: []string{
+				"out/soong/.intermediates/default/java/android_stubs_current/android_common/turbine-combined/android_stubs_current.jar",
+				"out/soong/.intermediates/transitive/android_common/busybox/R.jar",
+			},
+			transitiveCombined: nil,
+
+			directImportResources: nil,
+			directImportOverlays:  []string{"out/soong/.intermediates/direct_import/android_common/flat-res/gen_res.flata"},
+			directImportImports: []string{
+				"out/soong/.intermediates/default/java/framework-res/android_common/package-res.apk",
+				"out/soong/.intermediates/direct_import_dep/android_common/package-res.apk",
+			},
+
+			transitiveImportResources: nil,
+			transitiveImportOverlays:  []string{"out/soong/.intermediates/transitive_import/android_common/flat-res/gen_res.flata"},
+			transitiveImportImports: []string{
+				"out/soong/.intermediates/default/java/framework-res/android_common/package-res.apk",
+				"out/soong/.intermediates/transitive_import_dep/android_common/package-res.apk",
+			},
+		}, {
+			// Test an app building with resource processor enabled but with dependencies built without
+			// resource processor.
+			name:                "app_resource_processor",
+			appUsesRP:           true,
+			directLibUsesRP:     false,
+			transitiveLibUsesRP: false,
+
+			appResources: nil,
+			appOverlays: []string{
+				"out/soong/.intermediates/transitive/android_common/package-res.apk",
+				"out/soong/.intermediates/transitive_import_dep/android_common/package-res.apk",
+				"out/soong/.intermediates/transitive_import/android_common/package-res.apk",
+				"out/soong/.intermediates/direct/android_common/package-res.apk",
+				"out/soong/.intermediates/direct_import_dep/android_common/package-res.apk",
+				"out/soong/.intermediates/direct_import/android_common/package-res.apk",
+				"out/soong/.intermediates/app/android_common/aapt2/app/res/values_strings.arsc.flat",
+			},
+			appImports: []string{"out/soong/.intermediates/default/java/framework-res/android_common/package-res.apk"},
+			appSrcJars: nil,
+			appClasspath: []string{
+				"out/soong/.intermediates/default/java/android_stubs_current/android_common/turbine-combined/android_stubs_current.jar",
+				// R.jar has to come before direct.jar
+				"out/soong/.intermediates/app/android_common/busybox/R.jar",
+				"out/soong/.intermediates/direct/android_common/turbine-combined/direct.jar",
+				"out/soong/.intermediates/direct_import/android_common/aar/classes-combined.jar",
+			},
+			appCombined: []string{
+				"out/soong/.intermediates/app/android_common/busybox/R.jar",
+				"out/soong/.intermediates/app/android_common/javac/app.jar",
+				"out/soong/.intermediates/direct/android_common/combined/direct.jar",
+				"out/soong/.intermediates/direct_import/android_common/aar/classes-combined.jar",
+			},
+
+			dontVerifyDirect:           true,
+			dontVerifyTransitive:       true,
+			dontVerifyDirectImport:     true,
+			dontVerifyTransitiveImport: true,
+		},
+		{
+			// Test an app building without resource processor enabled but with a dependency built with
+			// resource processor.
+			name:                "app_dependency_lib_resource_processor",
+			appUsesRP:           false,
+			directLibUsesRP:     true,
+			transitiveLibUsesRP: false,
+
+			appOverlays: []string{
+				"out/soong/.intermediates/transitive/android_common/package-res.apk",
+				"out/soong/.intermediates/transitive_import_dep/android_common/package-res.apk",
+				"out/soong/.intermediates/transitive_import/android_common/package-res.apk",
+				"out/soong/.intermediates/direct/android_common/package-res.apk",
+				"out/soong/.intermediates/direct_import_dep/android_common/package-res.apk",
+				"out/soong/.intermediates/direct_import/android_common/package-res.apk",
+				"out/soong/.intermediates/app/android_common/aapt2/app/res/values_strings.arsc.flat",
+			},
+			appImports: []string{"out/soong/.intermediates/default/java/framework-res/android_common/package-res.apk"},
+			appSrcJars: []string{"out/soong/.intermediates/app/android_common/gen/android/R.srcjar"},
+			appClasspath: []string{
+				"out/soong/.intermediates/default/java/android_stubs_current/android_common/turbine-combined/android_stubs_current.jar",
+				"out/soong/.intermediates/direct/android_common/turbine-combined/direct.jar",
+				"out/soong/.intermediates/direct_import/android_common/aar/classes-combined.jar",
+			},
+			appCombined: []string{
+				"out/soong/.intermediates/app/android_common/javac/app.jar",
+				"out/soong/.intermediates/direct/android_common/combined/direct.jar",
+				"out/soong/.intermediates/direct_import/android_common/aar/classes-combined.jar",
+			},
+
+			directResources: nil,
+			directOverlays:  []string{"out/soong/.intermediates/direct/android_common/aapt2/direct/res/values_strings.arsc.flat"},
+			directImports: []string{
+				"out/soong/.intermediates/default/java/framework-res/android_common/package-res.apk",
+				"out/soong/.intermediates/transitive_import/android_common/package-res.apk",
+				"out/soong/.intermediates/transitive_import_dep/android_common/package-res.apk",
+				"out/soong/.intermediates/transitive/android_common/package-res.apk",
+			},
+			directSrcJars: nil,
+			directClasspath: []string{
+				"out/soong/.intermediates/default/java/android_stubs_current/android_common/turbine-combined/android_stubs_current.jar",
+				"out/soong/.intermediates/transitive_import/android_common/busybox/R.jar",
+				"out/soong/.intermediates/transitive_import_dep/android_common/busybox/R.jar",
+				"out/soong/.intermediates/direct/android_common/busybox/R.jar",
+				"out/soong/.intermediates/transitive/android_common/turbine-combined/transitive.jar",
+				"out/soong/.intermediates/transitive_import/android_common/aar/classes-combined.jar",
+			},
+			directCombined: []string{
+				"out/soong/.intermediates/direct/android_common/javac/direct.jar",
+				"out/soong/.intermediates/transitive/android_common/javac/transitive.jar",
+				"out/soong/.intermediates/transitive_import/android_common/aar/classes-combined.jar",
+			},
+
+			dontVerifyTransitive:       true,
+			dontVerifyDirectImport:     true,
+			dontVerifyTransitiveImport: true,
+		},
+		{
+			// Test a library building without resource processor enabled but with a dependency built with
+			// resource processor.
+			name:                "lib_dependency_lib_resource_processor",
+			appUsesRP:           false,
+			directLibUsesRP:     false,
+			transitiveLibUsesRP: true,
+
+			appOverlays: []string{
+				"out/soong/.intermediates/transitive/android_common/package-res.apk",
+				"out/soong/.intermediates/transitive_import_dep/android_common/package-res.apk",
+				"out/soong/.intermediates/transitive_import/android_common/package-res.apk",
+				"out/soong/.intermediates/direct/android_common/package-res.apk",
+				"out/soong/.intermediates/direct_import_dep/android_common/package-res.apk",
+				"out/soong/.intermediates/direct_import/android_common/package-res.apk",
+				"out/soong/.intermediates/app/android_common/aapt2/app/res/values_strings.arsc.flat",
+			},
+			appImports: []string{"out/soong/.intermediates/default/java/framework-res/android_common/package-res.apk"},
+			appSrcJars: []string{"out/soong/.intermediates/app/android_common/gen/android/R.srcjar"},
+			appClasspath: []string{
+				"out/soong/.intermediates/default/java/android_stubs_current/android_common/turbine-combined/android_stubs_current.jar",
+				"out/soong/.intermediates/direct/android_common/turbine-combined/direct.jar",
+				"out/soong/.intermediates/direct_import/android_common/aar/classes-combined.jar",
+			},
+			appCombined: []string{
+				"out/soong/.intermediates/app/android_common/javac/app.jar",
+				"out/soong/.intermediates/direct/android_common/combined/direct.jar",
+				"out/soong/.intermediates/direct_import/android_common/aar/classes-combined.jar",
+			},
+
+			directResources: nil,
+			directOverlays: []string{
+				"out/soong/.intermediates/transitive/android_common/package-res.apk",
+				"out/soong/.intermediates/transitive_import_dep/android_common/package-res.apk",
+				"out/soong/.intermediates/transitive_import/android_common/package-res.apk",
+				"out/soong/.intermediates/direct/android_common/aapt2/direct/res/values_strings.arsc.flat",
+			},
+			directImports: []string{"out/soong/.intermediates/default/java/framework-res/android_common/package-res.apk"},
+			directSrcJars: []string{"out/soong/.intermediates/direct/android_common/gen/android/R.srcjar"},
+			directClasspath: []string{
+				"out/soong/.intermediates/default/java/android_stubs_current/android_common/turbine-combined/android_stubs_current.jar",
+				"out/soong/.intermediates/transitive/android_common/turbine-combined/transitive.jar",
+				"out/soong/.intermediates/transitive_import/android_common/aar/classes-combined.jar",
+			},
+			directCombined: []string{
+				"out/soong/.intermediates/direct/android_common/javac/direct.jar",
+				"out/soong/.intermediates/transitive/android_common/javac/transitive.jar",
+				"out/soong/.intermediates/transitive_import/android_common/aar/classes-combined.jar",
+			},
+
+			transitiveResources: []string{"out/soong/.intermediates/transitive/android_common/aapt2/transitive/res/values_strings.arsc.flat"},
+			transitiveOverlays:  nil,
+			transitiveImports:   []string{"out/soong/.intermediates/default/java/framework-res/android_common/package-res.apk"},
+			transitiveSrcJars:   nil,
+			transitiveClasspath: []string{
+				"out/soong/.intermediates/default/java/android_stubs_current/android_common/turbine-combined/android_stubs_current.jar",
+				"out/soong/.intermediates/transitive/android_common/busybox/R.jar",
+			},
+			transitiveCombined: nil,
+
+			dontVerifyDirectImport:     true,
+			dontVerifyTransitiveImport: true,
 		},
 	}

@@ -839,6 +1083,7 @@ func TestAndroidResourceProcessor(t *testing.T) {
 					resource_dirs: ["app/res"],
 					manifest: "app/AndroidManifest.xml",
 					static_libs: ["direct", "direct_import"],
+					use_resource_processor: %v,
 				}

 				android_library {
@@ -848,6 +1093,7 @@ func TestAndroidResourceProcessor(t *testing.T) {
 					resource_dirs: ["direct/res"],
 					manifest: "direct/AndroidManifest.xml",
 					static_libs: ["transitive", "transitive_import"],
+					use_resource_processor: %v,
 				}

 				android_library {
@@ -856,6 +1102,7 @@ func TestAndroidResourceProcessor(t *testing.T) {
 					srcs: ["transitive/transitive.java"],
 					resource_dirs: ["transitive/res"],
 					manifest: "transitive/AndroidManifest.xml",
+					use_resource_processor: %v,
 				}

 				android_library_import {
@@ -883,7 +1130,7 @@ func TestAndroidResourceProcessor(t *testing.T) {
 					sdk_version: "current",
 					aars: ["transitive_import_dep.aar"],
 				}
-			`)
+			`, testCase.appUsesRP, testCase.directLibUsesRP, testCase.transitiveLibUsesRP)

 			fs := android.MockFS{
 				"app/res/values/strings.xml":        nil,
--- a/java/base.go
+++ b/java/base.go
@@ -1057,7 +1057,7 @@ func (module *Module) addGeneratedSrcJars(path android.Path) {
 	module.properties.Generated_srcjars = append(module.properties.Generated_srcjars, path)
 }

-func (j *Module) compile(ctx android.ModuleContext, aaptSrcJar android.Path) {
+func (j *Module) compile(ctx android.ModuleContext, extraSrcJars, extraClasspathJars, extraCombinedJars android.Paths) {
 	j.exportAidlIncludeDirs = android.PathsForModuleSrc(ctx, j.deviceProperties.Aidl.Export_include_dirs)

 	deps := j.collectDeps(ctx)
@@ -1095,9 +1095,7 @@ func (j *Module) compile(ctx android.ModuleContext, aaptSrcJar android.Path) {

 	srcJars := srcFiles.FilterByExt(".srcjar")
 	srcJars = append(srcJars, deps.srcJars...)
-	if aaptSrcJar != nil {
-		srcJars = append(srcJars, aaptSrcJar)
-	}
+	srcJars = append(srcJars, extraSrcJars...)
 	srcJars = append(srcJars, j.properties.Generated_srcjars...)
 	srcFiles = srcFiles.FilterOutByExt(".srcjar")

@@ -1140,6 +1138,11 @@ func (j *Module) compile(ctx android.ModuleContext, aaptSrcJar android.Path) {
 	var kotlinJars android.Paths
 	var kotlinHeaderJars android.Paths

+	// Prepend extraClasspathJars to classpath so that the resource processor R.jar comes before
+	// any dependencies so that it can override any non-final R classes from dependencies with the
+	// final R classes from the app.
+	flags.classpath = append(android.CopyOf(extraClasspathJars), flags.classpath...)
+
 	if srcFiles.HasExt(".kt") {
 		// When using kotlin sources turbine is used to generate annotation processor sources,
 		// including for annotation processors that generate API, so we can use turbine for
@@ -1233,8 +1236,9 @@ func (j *Module) compile(ctx android.ModuleContext, aaptSrcJar android.Path) {
 			// allow for the use of annotation processors that do function correctly
 			// with sharding enabled. See: b/77284273.
 		}
+		extraJars := append(android.CopyOf(extraCombinedJars), kotlinHeaderJars...)
 		headerJarFileWithoutDepsOrJarjar, j.headerJarFile =
-			j.compileJavaHeader(ctx, uniqueJavaFiles, srcJars, deps, flags, jarName, kotlinHeaderJars)
+			j.compileJavaHeader(ctx, uniqueJavaFiles, srcJars, deps, flags, jarName, extraJars)
 		if ctx.Failed() {
 			return
 		}
@@ -1385,6 +1389,8 @@ func (j *Module) compile(ctx android.ModuleContext, aaptSrcJar android.Path) {
 		jars = append(jars, servicesJar)
 	}

+	jars = append(android.CopyOf(extraCombinedJars), jars...)
+
 	// Combine the classes built from sources, any manifests, and any static libraries into
 	// classes.jar. If there is only one input jar this step will be skipped.
 	var outputFile android.OutputPath
--- a/java/config/config.go
+++ b/java/config/config.go
@@ -148,6 +148,8 @@ func init() {
 	pctx.SourcePathVariable("JavaKytheExtractorJar", "prebuilts/build-tools/common/framework/javac_extractor.jar")
 	pctx.SourcePathVariable("Ziptime", "prebuilts/build-tools/${hostPrebuiltTag}/bin/ziptime")

+	pctx.SourcePathVariable("ResourceProcessorBusyBox", "prebuilts/bazel/common/android_tools/android_tools/all_android_tools_deploy.jar")
+
 	pctx.HostBinToolVariable("GenKotlinBuildFileCmd", "gen-kotlin-build-file")

 	pctx.SourcePathVariable("JarArgsCmd", "build/soong/scripts/jar-args.sh")
--- a/java/java.go
+++ b/java/java.go
@@ -692,7 +692,7 @@ func (j *Library) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 		j.dexpreopter.uncompressedDex = *j.dexProperties.Uncompress_dex
 		j.classLoaderContexts = j.usesLibrary.classLoaderContextForUsesLibDeps(ctx)
 	}
-	j.compile(ctx, nil)
+	j.compile(ctx, nil, nil, nil)

 	// Collect the module directory for IDE info in java/jdeps.go.
 	j.modulePaths = append(j.modulePaths, ctx.ModuleDir())