diff --git a/android/allowlists/allowlists.go b/android/allowlists/allowlists.go
index 26cfd57..28dc8b4 100644
--- a/android/allowlists/allowlists.go
+++ b/android/allowlists/allowlists.go
@@ -104,12 +104,14 @@
 		"external/google-benchmark":                          Bp2BuildDefaultTrueRecursively,
 		"external/googletest":                                Bp2BuildDefaultTrueRecursively,
 		"external/gwp_asan":                                  Bp2BuildDefaultTrueRecursively,
+		"external/hamcrest":                                  Bp2BuildDefaultTrueRecursively,
 		"external/icu":                                       Bp2BuildDefaultTrueRecursively,
 		"external/icu/android_icu4j":                         Bp2BuildDefaultFalse, // java rules incomplete
 		"external/icu/icu4j":                                 Bp2BuildDefaultFalse, // java rules incomplete
 		"external/javapoet":                                  Bp2BuildDefaultTrueRecursively,
 		"external/jemalloc_new":                              Bp2BuildDefaultTrueRecursively,
 		"external/jsoncpp":                                   Bp2BuildDefaultTrueRecursively,
+		"external/junit":                                     Bp2BuildDefaultTrueRecursively,
 		"external/libcap":                                    Bp2BuildDefaultTrueRecursively,
 		"external/libcxx":                                    Bp2BuildDefaultTrueRecursively,
 		"external/libcxxabi":                                 Bp2BuildDefaultTrueRecursively,
@@ -122,6 +124,7 @@
 		"external/pcre":                                      Bp2BuildDefaultTrueRecursively,
 		"external/protobuf":                                  Bp2BuildDefaultTrueRecursively,
 		"external/python/six":                                Bp2BuildDefaultTrueRecursively,
+		"external/rappor":                                    Bp2BuildDefaultTrueRecursively,
 		"external/scudo":                                     Bp2BuildDefaultTrueRecursively,
 		"external/selinux/libselinux":                        Bp2BuildDefaultTrueRecursively,
 		"external/selinux/libsepol":                          Bp2BuildDefaultTrueRecursively,
diff --git a/android/apex.go b/android/apex.go
index b127f74..030fbdc 100644
--- a/android/apex.go
+++ b/android/apex.go
@@ -870,10 +870,6 @@
 	"gemmlowp_headers":                                         30,
 	"guava-listenablefuture-prebuilt-jar":                      30,
 	"ike-internals":                                            30,
-	"kotlinx-coroutines-android":                               28,
-	"kotlinx-coroutines-android-nodeps":                        30,
-	"kotlinx-coroutines-core":                                  28,
-	"kotlinx-coroutines-core-nodeps":                           30,
 	"libbrotli":                                                30,
 	"libcrypto_static":                                         30,
 	"libeigen":                                                 30,
diff --git a/android/bazel_handler.go b/android/bazel_handler.go
index 6b2be69..fa26fc8 100644
--- a/android/bazel_handler.go
+++ b/android/bazel_handler.go
@@ -28,6 +28,7 @@
 
 	"android/soong/bazel/cquery"
 	"android/soong/shared"
+	"github.com/google/blueprint"
 
 	"android/soong/bazel"
 )
@@ -101,6 +102,9 @@
 
 	// Returns build statements which should get registered to reflect Bazel's outputs.
 	BuildStatementsToRegister() []bazel.BuildStatement
+
+	// Returns the depsets defined in Bazel's aquery response.
+	AqueryDepsets() []bazel.AqueryDepset
 }
 
 type bazelRunner interface {
@@ -128,6 +132,9 @@
 
 	// Build statements which should get registered to reflect Bazel's outputs.
 	buildStatements []bazel.BuildStatement
+
+	// Depsets which should be used for Bazel's build statements.
+	depsets []bazel.AqueryDepset
 }
 
 var _ BazelContext = &bazelContext{}
@@ -175,6 +182,10 @@
 	return []bazel.BuildStatement{}
 }
 
+func (m MockBazelContext) AqueryDepsets() []bazel.AqueryDepset {
+	return []bazel.AqueryDepset{}
+}
+
 var _ BazelContext = MockBazelContext{}
 
 func (bazelCtx *bazelContext) GetOutputFiles(label string, cfgKey configKey) ([]string, bool) {
@@ -236,6 +247,10 @@
 	return []bazel.BuildStatement{}
 }
 
+func (m noopBazelContext) AqueryDepsets() []bazel.AqueryDepset {
+	return []bazel.AqueryDepset{}
+}
+
 func NewBazelContext(c *config) (BazelContext, error) {
 	// TODO(cparsons): Assess USE_BAZEL=1 instead once "mixed Soong/Bazel builds"
 	// are production ready.
@@ -746,7 +761,7 @@
 		return err
 	}
 
-	context.buildStatements, err = bazel.AqueryBuildStatements([]byte(aqueryOutput))
+	context.buildStatements, context.depsets, err = bazel.AqueryBuildStatements([]byte(aqueryOutput))
 	if err != nil {
 		return err
 	}
@@ -772,6 +787,10 @@
 	return context.buildStatements
 }
 
+func (context *bazelContext) AqueryDepsets() []bazel.AqueryDepset {
+	return context.depsets
+}
+
 func (context *bazelContext) OutputBase() string {
 	return context.paths.outputBase
 }
@@ -804,6 +823,23 @@
 		ctx.AddNinjaFileDeps(file)
 	}
 
+	for _, depset := range ctx.Config().BazelContext.AqueryDepsets() {
+		var outputs []Path
+		for _, depsetDepId := range depset.TransitiveDepSetIds {
+			otherDepsetName := bazelDepsetName(depsetDepId)
+			outputs = append(outputs, PathForPhony(ctx, otherDepsetName))
+		}
+		for _, artifactPath := range depset.DirectArtifacts {
+			outputs = append(outputs, PathForBazelOut(ctx, artifactPath))
+		}
+		thisDepsetName := bazelDepsetName(depset.Id)
+		ctx.Build(pctx, BuildParams{
+			Rule:      blueprint.Phony,
+			Outputs:   []WritablePath{PathForPhony(ctx, thisDepsetName)},
+			Implicits: outputs,
+		})
+	}
+
 	// Register bazel-owned build statements (obtained from the aquery invocation).
 	for index, buildStatement := range ctx.Config().BazelContext.BuildStatementsToRegister() {
 		if len(buildStatement.Command) < 1 {
@@ -838,6 +874,10 @@
 		for _, inputPath := range buildStatement.InputPaths {
 			cmd.Implicit(PathForBazelOut(ctx, inputPath))
 		}
+		for _, inputDepsetId := range buildStatement.InputDepsetIds {
+			otherDepsetName := bazelDepsetName(inputDepsetId)
+			cmd.Implicit(PathForPhony(ctx, otherDepsetName))
+		}
 
 		if depfile := buildStatement.Depfile; depfile != nil {
 			cmd.ImplicitDepFile(PathForBazelOut(ctx, *depfile))
@@ -883,3 +923,7 @@
 		osType: ctx.Os(),
 	}
 }
+
+func bazelDepsetName(depsetId int) string {
+	return fmt.Sprintf("bazel_depset_%d", depsetId)
+}
diff --git a/android/config.go b/android/config.go
index 250c312..ee058e8 100644
--- a/android/config.go
+++ b/android/config.go
@@ -1486,6 +1486,10 @@
 	return c.productVariables.MissingUsesLibraries
 }
 
+func (c *config) TargetMultitreeUpdateMeta() bool {
+	return c.productVariables.MultitreeUpdateMeta
+}
+
 func (c *deviceConfig) DeviceArch() string {
 	return String(c.config.productVariables.DeviceArch)
 }
diff --git a/android/paths.go b/android/paths.go
index e7829b9..e0e5ae5 100644
--- a/android/paths.go
+++ b/android/paths.go
@@ -1057,7 +1057,8 @@
 	}
 
 	// absolute path already checked by validateSafePath
-	if strings.HasPrefix(ret.String(), ctx.Config().soongOutDir) {
+	// special-case api surface gen files for now
+	if strings.HasPrefix(ret.String(), ctx.Config().soongOutDir) && !strings.Contains(ret.String(), ctx.Config().soongOutDir+"/.export") {
 		return ret, fmt.Errorf("source path %q is in output", ret.String())
 	}
 
@@ -1073,7 +1074,8 @@
 	}
 
 	// absolute path already checked by validatePath
-	if strings.HasPrefix(ret.String(), ctx.Config().soongOutDir) {
+	// special-case for now
+	if strings.HasPrefix(ret.String(), ctx.Config().soongOutDir) && !strings.Contains(ret.String(), ctx.Config().soongOutDir+"/.export") {
 		return ret, fmt.Errorf("source path %q is in output", ret.String())
 	}
 
diff --git a/android/variable.go b/android/variable.go
index 373891a..90cb6ff 100644
--- a/android/variable.go
+++ b/android/variable.go
@@ -352,6 +352,8 @@
 	RecoverySnapshotDirsIncluded []string `json:",omitempty"`
 	HostFakeSnapshotEnabled      bool     `json:",omitempty"`
 
+	MultitreeUpdateMeta bool `json:",omitempty"`
+
 	BoardVendorSepolicyDirs           []string `json:",omitempty"`
 	BoardOdmSepolicyDirs              []string `json:",omitempty"`
 	BoardReqdMaskPolicy               []string `json:",omitempty"`
diff --git a/androidmk/parser/make_strings.go b/androidmk/parser/make_strings.go
index 8030326..416e430 100644
--- a/androidmk/parser/make_strings.go
+++ b/androidmk/parser/make_strings.go
@@ -279,7 +279,7 @@
 
 func (ms *MakeString) EndsWith(ch rune) bool {
 	s := ms.Strings[len(ms.Strings)-1]
-	return s[len(s)-1] == uint8(ch)
+	return len(s) > 0 && s[len(s)-1] == uint8(ch)
 }
 
 func (ms *MakeString) ReplaceLiteral(input string, output string) {
diff --git a/androidmk/parser/make_strings_test.go b/androidmk/parser/make_strings_test.go
index fbb289b..e243ece 100644
--- a/androidmk/parser/make_strings_test.go
+++ b/androidmk/parser/make_strings_test.go
@@ -217,6 +217,36 @@
 	}
 }
 
+var endsWithTestCases = []struct {
+	in       *MakeString
+	endsWith rune
+	expected bool
+}{
+	{
+		in:       genMakeString("foo", "X", "bar ="),
+		endsWith: '=',
+		expected: true,
+	},
+	{
+		in:       genMakeString("foo", "X", "bar ="),
+		endsWith: ':',
+		expected: false,
+	},
+	{
+		in:       genMakeString("foo", "X", ""),
+		endsWith: '=',
+		expected: false,
+	},
+}
+
+func TestMakeStringEndsWith(t *testing.T) {
+	for _, test := range endsWithTestCases {
+		if test.in.EndsWith(test.endsWith) != test.expected {
+			t.Errorf("with:\n%q\nexpected:\n%t\ngot:\n%t", test.in.Dump(), test.expected, !test.expected)
+		}
+	}
+}
+
 func dumpArray(a []*MakeString) string {
 	ret := make([]string, len(a))
 
diff --git a/apex/Android.bp b/apex/Android.bp
index 41224ec..d3417c2 100644
--- a/apex/Android.bp
+++ b/apex/Android.bp
@@ -14,6 +14,7 @@
         "soong-cc",
         "soong-filesystem",
         "soong-java",
+        "soong-multitree",
         "soong-provenance",
         "soong-python",
         "soong-rust",
diff --git a/apex/apex.go b/apex/apex.go
index 76af1b8..f16b72d 100644
--- a/apex/apex.go
+++ b/apex/apex.go
@@ -33,6 +33,7 @@
 	prebuilt_etc "android/soong/etc"
 	"android/soong/filesystem"
 	"android/soong/java"
+	"android/soong/multitree"
 	"android/soong/python"
 	"android/soong/rust"
 	"android/soong/sh"
@@ -358,6 +359,7 @@
 	android.OverridableModuleBase
 	android.SdkBase
 	android.BazelModuleBase
+	multitree.ExportableModuleBase
 
 	// Properties
 	properties            apexBundleProperties
@@ -1359,6 +1361,21 @@
 	}
 }
 
+var _ multitree.Exportable = (*apexBundle)(nil)
+
+func (a *apexBundle) Exportable() bool {
+	if a.properties.ApexType == flattenedApex {
+		return false
+	}
+	return true
+}
+
+func (a *apexBundle) TaggedOutputs() map[string]android.Paths {
+	ret := make(map[string]android.Paths)
+	ret["apex"] = android.Paths{a.outputFile}
+	return ret
+}
+
 var _ cc.Coverage = (*apexBundle)(nil)
 
 // Implements cc.Coverage
@@ -2372,6 +2389,7 @@
 	android.InitSdkAwareModule(module)
 	android.InitOverridableModule(module, &module.overridableProperties.Overrides)
 	android.InitBazelModule(module)
+	multitree.InitExportableModule(module)
 	return module
 }
 
diff --git a/bazel/aquery.go b/bazel/aquery.go
index fd8cf67..e05cbd6 100644
--- a/bazel/aquery.go
+++ b/bazel/aquery.go
@@ -43,6 +43,18 @@
 	Value string
 }
 
+// AqueryDepset is a depset definition from Bazel's aquery response. This is
+// akin to the `depSetOfFiles` in the response proto, except that direct
+// artifacts are enumerated by full path instead of by ID.
+// A depset is a data structure for efficient transitive handling of artifact
+// paths. A single depset consists of one or more artifact paths and one or
+// more "child" depsets.
+type AqueryDepset struct {
+	Id                  int
+	DirectArtifacts     []string
+	TransitiveDepSetIds []int
+}
+
 // depSetOfFiles contains relevant portions of Bazel's aquery proto, DepSetOfFiles.
 // Represents a data structure containing one or more files. Depsets in Bazel are an efficient
 // data structure for storing large numbers of file paths.
@@ -79,21 +91,21 @@
 	Command      string
 	Depfile      *string
 	OutputPaths  []string
-	InputPaths   []string
 	SymlinkPaths []string
 	Env          []KeyValuePair
 	Mnemonic     string
+
+	// Inputs of this build statement, either as unexpanded depsets or expanded
+	// input paths. There should be no overlap between these fields; an input
+	// path should either be included as part of an unexpanded depset or a raw
+	// input path string, but not both.
+	InputDepsetIds []int
+	InputPaths     []string
 }
 
 // A helper type for aquery processing which facilitates retrieval of path IDs from their
 // less readable Bazel structures (depset and path fragment).
 type aqueryArtifactHandler struct {
-	// Maps middleman artifact Id to input artifact depset ID.
-	// Middleman artifacts are treated as "substitute" artifacts for mixed builds. For example,
-	// if we find a middleman action which has outputs [foo, bar], and output [baz_middleman], then,
-	// for each other action which has input [baz_middleman], we add [foo, bar] to the inputs for
-	// that action instead.
-	middlemanIdToDepsetIds map[int][]int
 	// Maps depset Id to depset struct.
 	depsetIdToDepset map[int]depSetOfFiles
 	// depsetIdToArtifactIdsCache is a memoization of depset flattening, because flattening
@@ -132,12 +144,11 @@
 		artifactIdToPath[artifact.Id] = artifactPath
 	}
 
-	depsetIdToDepset := map[int]depSetOfFiles{}
-	for _, depset := range aqueryResult.DepSetOfFiles {
-		depsetIdToDepset[depset.Id] = depset
-	}
-
-	// Do a pass through all actions to identify which artifacts are middleman artifacts.
+	// Map middleman artifact Id to input artifact depset ID.
+	// Middleman artifacts are treated as "substitute" artifacts for mixed builds. For example,
+	// if we find a middleman action which has outputs [foo, bar], and output [baz_middleman], then,
+	// for each other action which has input [baz_middleman], we add [foo, bar] to the inputs for
+	// that action instead.
 	middlemanIdToDepsetIds := map[int][]int{}
 	for _, actionEntry := range aqueryResult.Actions {
 		if actionEntry.Mnemonic == "Middleman" {
@@ -146,14 +157,64 @@
 			}
 		}
 	}
+
+	// Store all depset IDs to validate all depset links are resolvable.
+	depsetIds := map[int]bool{}
+	for _, depset := range aqueryResult.DepSetOfFiles {
+		depsetIds[depset.Id] = true
+	}
+
+	depsetIdToDepset := map[int]depSetOfFiles{}
+	// Validate and adjust aqueryResult.DepSetOfFiles values.
+	for _, depset := range aqueryResult.DepSetOfFiles {
+		filteredArtifactIds := []int{}
+		for _, artifactId := range depset.DirectArtifactIds {
+			path, pathExists := artifactIdToPath[artifactId]
+			if !pathExists {
+				return nil, fmt.Errorf("undefined input artifactId %d", artifactId)
+			}
+			// Filter out any inputs which are universally dropped, and swap middleman
+			// artifacts with their corresponding depsets.
+			if depsetsToUse, isMiddleman := middlemanIdToDepsetIds[artifactId]; isMiddleman {
+				// Swap middleman artifacts with their corresponding depsets and drop the middleman artifacts.
+				depset.TransitiveDepSetIds = append(depset.TransitiveDepSetIds, depsetsToUse...)
+			} else if strings.HasSuffix(path, py3wrapperFileName) || manifestFilePattern.MatchString(path) {
+				// Drop these artifacts.
+				// See go/python-binary-host-mixed-build for more details.
+				// 1) For py3wrapper.sh, there is no action for creating py3wrapper.sh in the aquery output of
+				// Bazel py_binary targets, so there is no Ninja build statements generated for creating it.
+				// 2) For MANIFEST file, SourceSymlinkManifest action is in aquery output of Bazel py_binary targets,
+				// but it doesn't contain sufficient information so no Ninja build statements are generated
+				// for creating it.
+				// So in mixed build mode, when these two are used as input of some Ninja build statement,
+				// since there is no build statement to create them, they should be removed from input paths.
+				// TODO(b/197135294): Clean up this custom runfiles handling logic when
+				// SourceSymlinkManifest and SymlinkTree actions are supported.
+			} else {
+				// TODO(b/216194240): Filter out bazel tools.
+				filteredArtifactIds = append(filteredArtifactIds, artifactId)
+			}
+		}
+		depset.DirectArtifactIds = filteredArtifactIds
+		for _, childDepsetId := range depset.TransitiveDepSetIds {
+			if _, exists := depsetIds[childDepsetId]; !exists {
+				return nil, fmt.Errorf("undefined input depsetId %d (referenced by depsetId %d)", childDepsetId, depset.Id)
+			}
+		}
+		depsetIdToDepset[depset.Id] = depset
+	}
+
 	return &aqueryArtifactHandler{
-		middlemanIdToDepsetIds:     middlemanIdToDepsetIds,
 		depsetIdToDepset:           depsetIdToDepset,
 		depsetIdToArtifactIdsCache: map[int][]int{},
 		artifactIdToPath:           artifactIdToPath,
 	}, nil
 }
 
+// getInputPaths flattens the depsets of the given IDs and returns all transitive
+// input paths contained in these depsets.
+// This is a potentially expensive operation, and should not be invoked except
+// for actions which need specialized input handling.
 func (a *aqueryArtifactHandler) getInputPaths(depsetIds []int) ([]string, error) {
 	inputPaths := []string{}
 
@@ -163,48 +224,15 @@
 			return nil, err
 		}
 		for _, inputId := range inputArtifacts {
-			if middlemanInputDepsetIds, isMiddlemanArtifact := a.middlemanIdToDepsetIds[inputId]; isMiddlemanArtifact {
-				// Add all inputs from middleman actions which created middleman artifacts which are
-				// in the inputs for this action.
-				swappedInputPaths, err := a.getInputPaths(middlemanInputDepsetIds)
-				if err != nil {
-					return nil, err
-				}
-				inputPaths = append(inputPaths, swappedInputPaths...)
-			} else {
-				inputPath, exists := a.artifactIdToPath[inputId]
-				if !exists {
-					return nil, fmt.Errorf("undefined input artifactId %d", inputId)
-				}
-				inputPaths = append(inputPaths, inputPath)
+			inputPath, exists := a.artifactIdToPath[inputId]
+			if !exists {
+				return nil, fmt.Errorf("undefined input artifactId %d", inputId)
 			}
+			inputPaths = append(inputPaths, inputPath)
 		}
 	}
 
-	// TODO(b/197135294): Clean up this custom runfiles handling logic when
-	// SourceSymlinkManifest and SymlinkTree actions are supported.
-	filteredInputPaths := filterOutPy3wrapperAndManifestFileFromInputPaths(inputPaths)
-
-	return filteredInputPaths, nil
-}
-
-// See go/python-binary-host-mixed-build for more details.
-// 1) For py3wrapper.sh, there is no action for creating py3wrapper.sh in the aquery output of
-// Bazel py_binary targets, so there is no Ninja build statements generated for creating it.
-// 2) For MANIFEST file, SourceSymlinkManifest action is in aquery output of Bazel py_binary targets,
-// but it doesn't contain sufficient information so no Ninja build statements are generated
-// for creating it.
-// So in mixed build mode, when these two are used as input of some Ninja build statement,
-// since there is no build statement to create them, they should be removed from input paths.
-func filterOutPy3wrapperAndManifestFileFromInputPaths(inputPaths []string) []string {
-	filteredInputPaths := []string{}
-	for _, path := range inputPaths {
-		if strings.HasSuffix(path, py3wrapperFileName) || manifestFilePattern.MatchString(path) {
-			continue
-		}
-		filteredInputPaths = append(filteredInputPaths, path)
-	}
-	return filteredInputPaths
+	return inputPaths, nil
 }
 
 func (a *aqueryArtifactHandler) artifactIdsFromDepsetId(depsetId int) ([]int, error) {
@@ -227,115 +255,233 @@
 	}
 }
 
-// AqueryBuildStatements returns an array of BuildStatements which should be registered (and output
-// to a ninja file) to correspond one-to-one with the given action graph json proto (from a bazel
-// aquery invocation).
-func AqueryBuildStatements(aqueryJsonProto []byte) ([]BuildStatement, error) {
+// AqueryBuildStatements returns a slice of BuildStatements and a slice of AqueryDepset
+// which should be registered (and output  to a ninja file) to correspond with Bazel's
+// action graph, as described by the given action graph json proto.
+// BuildStatements are one-to-one with actions in the given action graph, and AqueryDepsets
+// are one-to-one with Bazel's depSetOfFiles objects.
+func AqueryBuildStatements(aqueryJsonProto []byte) ([]BuildStatement, []AqueryDepset, error) {
 	buildStatements := []BuildStatement{}
+	depsets := []AqueryDepset{}
 
 	var aqueryResult actionGraphContainer
 	err := json.Unmarshal(aqueryJsonProto, &aqueryResult)
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 	aqueryHandler, err := newAqueryHandler(aqueryResult)
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 
 	for _, actionEntry := range aqueryResult.Actions {
 		if shouldSkipAction(actionEntry) {
 			continue
 		}
-		outputPaths := []string{}
-		var depfile *string
-		for _, outputId := range actionEntry.OutputIds {
-			outputPath, exists := aqueryHandler.artifactIdToPath[outputId]
-			if !exists {
-				return nil, fmt.Errorf("undefined outputId %d", outputId)
-			}
-			ext := filepath.Ext(outputPath)
-			if ext == ".d" {
-				if depfile != nil {
-					return nil, fmt.Errorf("found multiple potential depfiles %q, %q", *depfile, outputPath)
-				} else {
-					depfile = &outputPath
-				}
-			} else {
-				outputPaths = append(outputPaths, outputPath)
-			}
-		}
-		inputPaths, err := aqueryHandler.getInputPaths(actionEntry.InputDepSetIds)
-		if err != nil {
-			return nil, err
-		}
 
-		buildStatement := BuildStatement{
-			Command:     strings.Join(proptools.ShellEscapeListIncludingSpaces(actionEntry.Arguments), " "),
-			Depfile:     depfile,
-			OutputPaths: outputPaths,
-			InputPaths:  inputPaths,
-			Env:         actionEntry.EnvironmentVariables,
-			Mnemonic:    actionEntry.Mnemonic,
-		}
-
+		var buildStatement BuildStatement
 		if isSymlinkAction(actionEntry) {
-			if len(inputPaths) != 1 || len(outputPaths) != 1 {
-				return nil, fmt.Errorf("Expect 1 input and 1 output to symlink action, got: input %q, output %q", inputPaths, outputPaths)
-			}
-			out := outputPaths[0]
-			outDir := proptools.ShellEscapeIncludingSpaces(filepath.Dir(out))
-			out = proptools.ShellEscapeIncludingSpaces(out)
-			in := filepath.Join("$PWD", proptools.ShellEscapeIncludingSpaces(inputPaths[0]))
-			// Use absolute paths, because some soong actions don't play well with relative paths (for example, `cp -d`).
-			buildStatement.Command = fmt.Sprintf("mkdir -p %[1]s && rm -f %[2]s && ln -sf %[3]s %[2]s", outDir, out, in)
-			buildStatement.SymlinkPaths = outputPaths[:]
+			buildStatement, err = aqueryHandler.symlinkActionBuildStatement(actionEntry)
 		} else if isTemplateExpandAction(actionEntry) && len(actionEntry.Arguments) < 1 {
-			if len(outputPaths) != 1 {
-				return nil, fmt.Errorf("Expect 1 output to template expand action, got: output %q", outputPaths)
-			}
-			expandedTemplateContent := expandTemplateContent(actionEntry)
-			// The expandedTemplateContent is escaped for being used in double quotes and shell unescape,
-			// and the new line characters (\n) are also changed to \\n which avoids some Ninja escape on \n, which might
-			// change \n to space and mess up the format of Python programs.
-			// sed is used to convert \\n back to \n before saving to output file.
-			// See go/python-binary-host-mixed-build for more details.
-			command := fmt.Sprintf(`/bin/bash -c 'echo "%[1]s" | sed "s/\\\\n/\\n/g" > %[2]s && chmod a+x %[2]s'`,
-				escapeCommandlineArgument(expandedTemplateContent), outputPaths[0])
-			buildStatement.Command = command
+			buildStatement, err = aqueryHandler.templateExpandActionBuildStatement(actionEntry)
 		} else if isPythonZipperAction(actionEntry) {
-			if len(inputPaths) < 1 || len(outputPaths) != 1 {
-				return nil, fmt.Errorf("Expect 1+ input and 1 output to python zipper action, got: input %q, output %q", inputPaths, outputPaths)
-			}
-			buildStatement.InputPaths, buildStatement.Command = removePy3wrapperScript(buildStatement)
-			buildStatement.Command = addCommandForPyBinaryRunfilesDir(buildStatement, inputPaths[0], outputPaths[0])
-			// Add the python zip file as input of the corresponding python binary stub script in Ninja build statements.
-			// In Ninja build statements, the outputs of dependents of a python binary have python binary stub script as input,
-			// which is not sufficient without the python zip file from which runfiles directory is created for py_binary.
-			//
-			// The following logic relies on that Bazel aquery output returns actions in the order that
-			// PythonZipper is after TemplateAction of creating Python binary stub script. If later Bazel doesn't return actions
-			// in that order, the following logic might not find the build statement generated for Python binary
-			// stub script and the build might fail. So the check of pyBinaryFound is added to help debug in case later Bazel might change aquery output.
-			// See go/python-binary-host-mixed-build for more details.
-			pythonZipFilePath := outputPaths[0]
-			pyBinaryFound := false
-			for i, _ := range buildStatements {
-				if len(buildStatements[i].OutputPaths) == 1 && buildStatements[i].OutputPaths[0]+".zip" == pythonZipFilePath {
-					buildStatements[i].InputPaths = append(buildStatements[i].InputPaths, pythonZipFilePath)
-					pyBinaryFound = true
-				}
-			}
-			if !pyBinaryFound {
-				return nil, fmt.Errorf("Could not find the correspondinging Python binary stub script of PythonZipper: %q", outputPaths)
-			}
+			buildStatement, err = aqueryHandler.pythonZipperActionBuildStatement(actionEntry, buildStatements)
 		} else if len(actionEntry.Arguments) < 1 {
-			return nil, fmt.Errorf("received action with no command: [%v]", buildStatement)
+			return nil, nil, fmt.Errorf("received action with no command: [%s]", actionEntry.Mnemonic)
+		} else {
+			buildStatement, err = aqueryHandler.normalActionBuildStatement(actionEntry)
+		}
+
+		if err != nil {
+			return nil, nil, err
 		}
 		buildStatements = append(buildStatements, buildStatement)
 	}
 
-	return buildStatements, nil
+	// Iterate over depset IDs in the initial aquery order to preserve determinism.
+	for _, depset := range aqueryResult.DepSetOfFiles {
+		// Use the depset in the aqueryHandler, as this contains the augmented depsets.
+		depset = aqueryHandler.depsetIdToDepset[depset.Id]
+		directPaths := []string{}
+		for _, artifactId := range depset.DirectArtifactIds {
+			pathString := aqueryHandler.artifactIdToPath[artifactId]
+			directPaths = append(directPaths, pathString)
+		}
+		aqueryDepset := AqueryDepset{
+			Id:                  depset.Id,
+			DirectArtifacts:     directPaths,
+			TransitiveDepSetIds: depset.TransitiveDepSetIds,
+		}
+		depsets = append(depsets, aqueryDepset)
+	}
+	return buildStatements, depsets, nil
+}
+
+func (aqueryHandler *aqueryArtifactHandler) validateInputDepsets(inputDepsetIds []int) ([]int, error) {
+	// Validate input depsets correspond to real depsets.
+	for _, depsetId := range inputDepsetIds {
+		if _, exists := aqueryHandler.depsetIdToDepset[depsetId]; !exists {
+			return nil, fmt.Errorf("undefined input depsetId %d", depsetId)
+		}
+	}
+	return inputDepsetIds, nil
+}
+
+func (aqueryHandler *aqueryArtifactHandler) normalActionBuildStatement(actionEntry action) (BuildStatement, error) {
+	command := strings.Join(proptools.ShellEscapeListIncludingSpaces(actionEntry.Arguments), " ")
+	inputDepsetIds, err := aqueryHandler.validateInputDepsets(actionEntry.InputDepSetIds)
+	if err != nil {
+		return BuildStatement{}, err
+	}
+	outputPaths, depfile, err := aqueryHandler.getOutputPaths(actionEntry)
+	if err != nil {
+		return BuildStatement{}, err
+	}
+
+	buildStatement := BuildStatement{
+		Command:        command,
+		Depfile:        depfile,
+		OutputPaths:    outputPaths,
+		InputDepsetIds: inputDepsetIds,
+		Env:            actionEntry.EnvironmentVariables,
+		Mnemonic:       actionEntry.Mnemonic,
+	}
+	return buildStatement, nil
+}
+
+func (aqueryHandler *aqueryArtifactHandler) pythonZipperActionBuildStatement(actionEntry action, prevBuildStatements []BuildStatement) (BuildStatement, error) {
+	inputPaths, err := aqueryHandler.getInputPaths(actionEntry.InputDepSetIds)
+	if err != nil {
+		return BuildStatement{}, err
+	}
+	outputPaths, depfile, err := aqueryHandler.getOutputPaths(actionEntry)
+	if err != nil {
+		return BuildStatement{}, err
+	}
+
+	if len(inputPaths) < 1 || len(outputPaths) != 1 {
+		return BuildStatement{}, fmt.Errorf("Expect 1+ input and 1 output to python zipper action, got: input %q, output %q", inputPaths, outputPaths)
+	}
+	command := strings.Join(proptools.ShellEscapeListIncludingSpaces(actionEntry.Arguments), " ")
+	inputPaths, command = removePy3wrapperScript(inputPaths, command)
+	command = addCommandForPyBinaryRunfilesDir(command, inputPaths[0], outputPaths[0])
+	// Add the python zip file as input of the corresponding python binary stub script in Ninja build statements.
+	// In Ninja build statements, the outputs of dependents of a python binary have python binary stub script as input,
+	// which is not sufficient without the python zip file from which runfiles directory is created for py_binary.
+	//
+	// The following logic relies on that Bazel aquery output returns actions in the order that
+	// PythonZipper is after TemplateAction of creating Python binary stub script. If later Bazel doesn't return actions
+	// in that order, the following logic might not find the build statement generated for Python binary
+	// stub script and the build might fail. So the check of pyBinaryFound is added to help debug in case later Bazel might change aquery output.
+	// See go/python-binary-host-mixed-build for more details.
+	pythonZipFilePath := outputPaths[0]
+	pyBinaryFound := false
+	for i, _ := range prevBuildStatements {
+		if len(prevBuildStatements[i].OutputPaths) == 1 && prevBuildStatements[i].OutputPaths[0]+".zip" == pythonZipFilePath {
+			prevBuildStatements[i].InputPaths = append(prevBuildStatements[i].InputPaths, pythonZipFilePath)
+			pyBinaryFound = true
+		}
+	}
+	if !pyBinaryFound {
+		return BuildStatement{}, fmt.Errorf("Could not find the correspondinging Python binary stub script of PythonZipper: %q", outputPaths)
+	}
+
+	buildStatement := BuildStatement{
+		Command:     command,
+		Depfile:     depfile,
+		OutputPaths: outputPaths,
+		InputPaths:  inputPaths,
+		Env:         actionEntry.EnvironmentVariables,
+		Mnemonic:    actionEntry.Mnemonic,
+	}
+	return buildStatement, nil
+}
+
+func (aqueryHandler *aqueryArtifactHandler) templateExpandActionBuildStatement(actionEntry action) (BuildStatement, error) {
+	outputPaths, depfile, err := aqueryHandler.getOutputPaths(actionEntry)
+	if err != nil {
+		return BuildStatement{}, err
+	}
+	if len(outputPaths) != 1 {
+		return BuildStatement{}, fmt.Errorf("Expect 1 output to template expand action, got: output %q", outputPaths)
+	}
+	expandedTemplateContent := expandTemplateContent(actionEntry)
+	// The expandedTemplateContent is escaped for being used in double quotes and shell unescape,
+	// and the new line characters (\n) are also changed to \\n which avoids some Ninja escape on \n, which might
+	// change \n to space and mess up the format of Python programs.
+	// sed is used to convert \\n back to \n before saving to output file.
+	// See go/python-binary-host-mixed-build for more details.
+	command := fmt.Sprintf(`/bin/bash -c 'echo "%[1]s" | sed "s/\\\\n/\\n/g" > %[2]s && chmod a+x %[2]s'`,
+		escapeCommandlineArgument(expandedTemplateContent), outputPaths[0])
+	inputDepsetIds, err := aqueryHandler.validateInputDepsets(actionEntry.InputDepSetIds)
+	if err != nil {
+		return BuildStatement{}, err
+	}
+
+	buildStatement := BuildStatement{
+		Command:        command,
+		Depfile:        depfile,
+		OutputPaths:    outputPaths,
+		InputDepsetIds: inputDepsetIds,
+		Env:            actionEntry.EnvironmentVariables,
+		Mnemonic:       actionEntry.Mnemonic,
+	}
+	return buildStatement, nil
+}
+
+func (aqueryHandler *aqueryArtifactHandler) symlinkActionBuildStatement(actionEntry action) (BuildStatement, error) {
+	outputPaths, depfile, err := aqueryHandler.getOutputPaths(actionEntry)
+	if err != nil {
+		return BuildStatement{}, err
+	}
+
+	inputPaths, err := aqueryHandler.getInputPaths(actionEntry.InputDepSetIds)
+	if err != nil {
+		return BuildStatement{}, err
+	}
+	if len(inputPaths) != 1 || len(outputPaths) != 1 {
+		return BuildStatement{}, fmt.Errorf("Expect 1 input and 1 output to symlink action, got: input %q, output %q", inputPaths, outputPaths)
+	}
+	out := outputPaths[0]
+	outDir := proptools.ShellEscapeIncludingSpaces(filepath.Dir(out))
+	out = proptools.ShellEscapeIncludingSpaces(out)
+	in := filepath.Join("$PWD", proptools.ShellEscapeIncludingSpaces(inputPaths[0]))
+	// Use absolute paths, because some soong actions don't play well with relative paths (for example, `cp -d`).
+	command := fmt.Sprintf("mkdir -p %[1]s && rm -f %[2]s && ln -sf %[3]s %[2]s", outDir, out, in)
+	symlinkPaths := outputPaths[:]
+
+	buildStatement := BuildStatement{
+		Command:      command,
+		Depfile:      depfile,
+		OutputPaths:  outputPaths,
+		InputPaths:   inputPaths,
+		Env:          actionEntry.EnvironmentVariables,
+		Mnemonic:     actionEntry.Mnemonic,
+		SymlinkPaths: symlinkPaths,
+	}
+	return buildStatement, nil
+}
+
+func (aqueryHandler *aqueryArtifactHandler) getOutputPaths(actionEntry action) (outputPaths []string, depfile *string, err error) {
+	for _, outputId := range actionEntry.OutputIds {
+		outputPath, exists := aqueryHandler.artifactIdToPath[outputId]
+		if !exists {
+			err = fmt.Errorf("undefined outputId %d", outputId)
+			return
+		}
+		ext := filepath.Ext(outputPath)
+		if ext == ".d" {
+			if depfile != nil {
+				err = fmt.Errorf("found multiple potential depfiles %q, %q", *depfile, outputPath)
+				return
+			} else {
+				depfile = &outputPath
+			}
+		} else {
+			outputPaths = append(outputPaths, outputPath)
+		}
+	}
+	return
 }
 
 // expandTemplateContent substitutes the tokens in a template.
@@ -372,10 +518,10 @@
 // removed from input paths and command of creating python zip file.
 // See go/python-binary-host-mixed-build for more details.
 // TODO(b/205879240) remove this after py3wrapper.sh could be created in the mixed build mode.
-func removePy3wrapperScript(bs BuildStatement) (newInputPaths []string, newCommand string) {
+func removePy3wrapperScript(inputPaths []string, command string) (newInputPaths []string, newCommand string) {
 	// Remove from inputs
 	filteredInputPaths := []string{}
-	for _, path := range bs.InputPaths {
+	for _, path := range inputPaths {
 		if !strings.HasSuffix(path, py3wrapperFileName) {
 			filteredInputPaths = append(filteredInputPaths, path)
 		}
@@ -384,7 +530,7 @@
 
 	// Remove from command line
 	var re = regexp.MustCompile(`\S*` + py3wrapperFileName)
-	newCommand = re.ReplaceAllString(bs.Command, "")
+	newCommand = re.ReplaceAllString(command, "")
 	return
 }
 
@@ -395,14 +541,14 @@
 // so MANIFEST file could not be created, which also blocks the creation of runfiles directory.
 // See go/python-binary-host-mixed-build for more details.
 // TODO(b/197135294) create runfiles directory from MANIFEST file once it can be created from SourceSymlinkManifest action.
-func addCommandForPyBinaryRunfilesDir(bs BuildStatement, zipperCommandPath, zipFilePath string) string {
+func addCommandForPyBinaryRunfilesDir(oldCommand string, zipperCommandPath, zipFilePath string) string {
 	// Unzip the zip file, zipFilePath looks like <python_binary>.zip
 	runfilesDirName := zipFilePath[0:len(zipFilePath)-4] + ".runfiles"
 	command := fmt.Sprintf("%s x %s -d %s", zipperCommandPath, zipFilePath, runfilesDirName)
 	// Create a symbolic link in <python_binary>.runfiles/, which is the expected structure
 	// when running the python binary stub script.
 	command += fmt.Sprintf(" && ln -sf runfiles/__main__ %s", runfilesDirName)
-	return bs.Command + " && " + command
+	return oldCommand + " && " + command
 }
 
 func isSymlinkAction(a action) bool {
diff --git a/bazel/aquery_test.go b/bazel/aquery_test.go
index 68e50c2..2328411 100644
--- a/bazel/aquery_test.go
+++ b/bazel/aquery_test.go
@@ -223,7 +223,7 @@
     "parentId": 13
   }]
 }`
-	actualbuildStatements, _ := AqueryBuildStatements([]byte(inputString))
+	actualbuildStatements, actualDepsets, _ := AqueryBuildStatements([]byte(inputString))
 	expectedBuildStatements := []BuildStatement{}
 	for _, arch := range []string{"arm", "arm64", "x86", "x86_64"} {
 		expectedBuildStatements = append(expectedBuildStatements,
@@ -234,11 +234,7 @@
 				OutputPaths: []string{
 					fmt.Sprintf("bazel-out/sourceroot/k8-fastbuild/bin/bionic/libc/syscalls-%s.S", arch),
 				},
-				InputPaths: []string{
-					"../sourceroot/bionic/libc/SYSCALLS.TXT",
-					"../sourceroot/bionic/libc/tools/gensyscalls.py",
-					"../bazel_tools/tools/genrule/genrule-setup.sh",
-				},
+				InputDepsetIds: []int{1},
 				Env: []KeyValuePair{
 					KeyValuePair{Key: "PATH", Value: "/bin:/usr/bin:/usr/local/bin"},
 				},
@@ -246,6 +242,16 @@
 			})
 	}
 	assertBuildStatements(t, expectedBuildStatements, actualbuildStatements)
+
+	expectedFlattenedInputs := []string{
+		"../sourceroot/bionic/libc/SYSCALLS.TXT",
+		"../sourceroot/bionic/libc/tools/gensyscalls.py",
+		"../bazel_tools/tools/genrule/genrule-setup.sh",
+	}
+	actualFlattenedInputs := flattenDepsets([]int{1}, actualDepsets)
+	if !reflect.DeepEqual(actualFlattenedInputs, expectedFlattenedInputs) {
+		t.Errorf("Expected flattened inputs %v, but got %v", expectedFlattenedInputs, actualFlattenedInputs)
+	}
 }
 
 func TestInvalidOutputId(t *testing.T) {
@@ -280,11 +286,11 @@
   }]
 }`
 
-	_, err := AqueryBuildStatements([]byte(inputString))
+	_, _, err := AqueryBuildStatements([]byte(inputString))
 	assertError(t, err, "undefined outputId 3")
 }
 
-func TestInvalidInputDepsetId(t *testing.T) {
+func TestInvalidInputDepsetIdFromAction(t *testing.T) {
 	const inputString = `
 {
   "artifacts": [{
@@ -316,10 +322,47 @@
   }]
 }`
 
-	_, err := AqueryBuildStatements([]byte(inputString))
+	_, _, err := AqueryBuildStatements([]byte(inputString))
 	assertError(t, err, "undefined input depsetId 2")
 }
 
+func TestInvalidInputDepsetIdFromDepset(t *testing.T) {
+	const inputString = `
+{
+  "artifacts": [{
+    "id": 1,
+    "pathFragmentId": 1
+  }, {
+    "id": 2,
+    "pathFragmentId": 2
+  }],
+  "actions": [{
+    "targetId": 1,
+    "actionKey": "x",
+    "mnemonic": "x",
+    "arguments": ["touch", "foo"],
+    "inputDepSetIds": [1],
+    "outputIds": [1],
+    "primaryOutputId": 1
+  }],
+  "depSetOfFiles": [{
+    "id": 1,
+    "directArtifactIds": [1, 2],
+    "transitiveDepSetIds": [42]
+  }],
+  "pathFragments": [{
+    "id": 1,
+    "label": "one"
+  }, {
+    "id": 2,
+    "label": "two"
+  }]
+}`
+
+	_, _, err := AqueryBuildStatements([]byte(inputString))
+	assertError(t, err, "undefined input depsetId 42 (referenced by depsetId 1)")
+}
+
 func TestInvalidInputArtifactId(t *testing.T) {
 	const inputString = `
 {
@@ -352,7 +395,7 @@
   }]
 }`
 
-	_, err := AqueryBuildStatements([]byte(inputString))
+	_, _, err := AqueryBuildStatements([]byte(inputString))
 	assertError(t, err, "undefined input artifactId 3")
 }
 
@@ -389,7 +432,7 @@
   }]
 }`
 
-	_, err := AqueryBuildStatements([]byte(inputString))
+	_, _, err := AqueryBuildStatements([]byte(inputString))
 	assertError(t, err, "undefined path fragment id 3")
 }
 
@@ -431,7 +474,7 @@
   }]
 }`
 
-	actual, err := AqueryBuildStatements([]byte(inputString))
+	actual, _, err := AqueryBuildStatements([]byte(inputString))
 	if err != nil {
 		t.Errorf("Unexpected error %q", err)
 	}
@@ -492,7 +535,7 @@
   }]
 }`
 
-	_, err := AqueryBuildStatements([]byte(inputString))
+	_, _, err := AqueryBuildStatements([]byte(inputString))
 	assertError(t, err, `found multiple potential depfiles "two.d", "other.d"`)
 }
 
@@ -699,23 +742,31 @@
   }]
 }`
 
-	actualbuildStatements, _ := AqueryBuildStatements([]byte(inputString))
-	// Inputs for the action are test_{i} from 1 to 20, and test_root. These inputs
-	// are given via a deep depset, but the depset is flattened when returned as a
-	// BuildStatement slice.
-	inputPaths := []string{"bazel-out/sourceroot/k8-fastbuild/bin/testpkg/test_root"}
-	for i := 1; i < 20; i++ {
-		inputPaths = append(inputPaths, fmt.Sprintf("bazel-out/sourceroot/k8-fastbuild/bin/testpkg/test_%d", i))
-	}
+	actualbuildStatements, actualDepsets, _ := AqueryBuildStatements([]byte(inputString))
+
 	expectedBuildStatements := []BuildStatement{
 		BuildStatement{
-			Command:     "/bin/bash -c 'touch bazel-out/sourceroot/k8-fastbuild/bin/testpkg/test_out'",
-			OutputPaths: []string{"bazel-out/sourceroot/k8-fastbuild/bin/testpkg/test_out"},
-			InputPaths:  inputPaths,
-			Mnemonic:    "Action",
+			Command:        "/bin/bash -c 'touch bazel-out/sourceroot/k8-fastbuild/bin/testpkg/test_out'",
+			OutputPaths:    []string{"bazel-out/sourceroot/k8-fastbuild/bin/testpkg/test_out"},
+			InputDepsetIds: []int{1},
+			Mnemonic:       "Action",
 		},
 	}
 	assertBuildStatements(t, expectedBuildStatements, actualbuildStatements)
+
+	// Inputs for the action are test_{i} from 1 to 20, and test_root. These inputs
+	// are given via a deep depset, but the depset is flattened when returned as a
+	// BuildStatement slice.
+	expectedFlattenedInputs := []string{}
+	for i := 1; i < 20; i++ {
+		expectedFlattenedInputs = append(expectedFlattenedInputs, fmt.Sprintf("bazel-out/sourceroot/k8-fastbuild/bin/testpkg/test_%d", i))
+	}
+	expectedFlattenedInputs = append(expectedFlattenedInputs, "bazel-out/sourceroot/k8-fastbuild/bin/testpkg/test_root")
+
+	actualFlattenedInputs := flattenDepsets([]int{1}, actualDepsets)
+	if !reflect.DeepEqual(actualFlattenedInputs, expectedFlattenedInputs) {
+		t.Errorf("Expected flattened inputs %v, but got %v", expectedFlattenedInputs, actualFlattenedInputs)
+	}
 }
 
 func TestMiddlemenAction(t *testing.T) {
@@ -785,24 +836,74 @@
   }]
 }`
 
-	actual, err := AqueryBuildStatements([]byte(inputString))
+	actualBuildStatements, actualDepsets, err := AqueryBuildStatements([]byte(inputString))
 	if err != nil {
 		t.Errorf("Unexpected error %q", err)
 	}
-	if expected := 1; len(actual) != expected {
-		t.Fatalf("Expected %d build statements, got %d", expected, len(actual))
+	if expected := 1; len(actualBuildStatements) != expected {
+		t.Fatalf("Expected %d build statements, got %d", expected, len(actualBuildStatements))
 	}
 
-	bs := actual[0]
-	expectedInputs := []string{"middleinput_one", "middleinput_two", "maininput_one", "maininput_two"}
-	if !reflect.DeepEqual(bs.InputPaths, expectedInputs) {
-		t.Errorf("Expected main action inputs %q, but got %q", expectedInputs, bs.InputPaths)
+	bs := actualBuildStatements[0]
+	if len(bs.InputPaths) > 0 {
+		t.Errorf("Expected main action raw inputs to be empty, but got %q", bs.InputPaths)
+	}
+
+	expectedInputDepsets := []int{2}
+	if !reflect.DeepEqual(bs.InputDepsetIds, expectedInputDepsets) {
+		t.Errorf("Expected main action depset IDs %v, but got %v", expectedInputDepsets, bs.InputDepsetIds)
 	}
 
 	expectedOutputs := []string{"output"}
 	if !reflect.DeepEqual(bs.OutputPaths, expectedOutputs) {
 		t.Errorf("Expected main action outputs %q, but got %q", expectedOutputs, bs.OutputPaths)
 	}
+
+	expectedAllDepsets := []AqueryDepset{
+		{
+			Id:              1,
+			DirectArtifacts: []string{"middleinput_one", "middleinput_two"},
+		},
+		{
+			Id:                  2,
+			DirectArtifacts:     []string{"maininput_one", "maininput_two"},
+			TransitiveDepSetIds: []int{1},
+		},
+	}
+	if !reflect.DeepEqual(actualDepsets, expectedAllDepsets) {
+		t.Errorf("Expected depsets %v, but got %v", expectedAllDepsets, actualDepsets)
+	}
+
+	expectedFlattenedInputs := []string{"middleinput_one", "middleinput_two", "maininput_one", "maininput_two"}
+	actualFlattenedInputs := flattenDepsets(bs.InputDepsetIds, actualDepsets)
+
+	if !reflect.DeepEqual(actualFlattenedInputs, expectedFlattenedInputs) {
+		t.Errorf("Expected flattened inputs %v, but got %v", expectedFlattenedInputs, actualFlattenedInputs)
+	}
+}
+
+// Returns the contents of given depsets in concatenated post order.
+func flattenDepsets(depsetIdsToFlatten []int, allDepsets []AqueryDepset) []string {
+	depsetsById := map[int]AqueryDepset{}
+	for _, depset := range allDepsets {
+		depsetsById[depset.Id] = depset
+	}
+	result := []string{}
+	for _, depsetId := range depsetIdsToFlatten {
+		result = append(result, flattenDepset(depsetId, depsetsById)...)
+	}
+	return result
+}
+
+// Returns the contents of a given depset in post order.
+func flattenDepset(depsetIdToFlatten int, allDepsets map[int]AqueryDepset) []string {
+	depset := allDepsets[depsetIdToFlatten]
+	result := []string{}
+	for _, depsetId := range depset.TransitiveDepSetIds {
+		result = append(result, flattenDepset(depsetId, allDepsets)...)
+	}
+	result = append(result, depset.DirectArtifacts...)
+	return result
 }
 
 func TestSimpleSymlink(t *testing.T) {
@@ -849,7 +950,7 @@
   }]
 }`
 
-	actual, err := AqueryBuildStatements([]byte(inputString))
+	actual, _, err := AqueryBuildStatements([]byte(inputString))
 
 	if err != nil {
 		t.Errorf("Unexpected error %q", err)
@@ -913,7 +1014,7 @@
   }]
 }`
 
-	actual, err := AqueryBuildStatements([]byte(inputString))
+	actual, _, err := AqueryBuildStatements([]byte(inputString))
 
 	if err != nil {
 		t.Errorf("Unexpected error %q", err)
@@ -970,7 +1071,7 @@
   }]
 }`
 
-	_, err := AqueryBuildStatements([]byte(inputString))
+	_, _, err := AqueryBuildStatements([]byte(inputString))
 	assertError(t, err, `Expect 1 input and 1 output to symlink action, got: input ["file" "other_file"], output ["symlink"]`)
 }
 
@@ -1011,7 +1112,7 @@
   }]
 }`
 
-	_, err := AqueryBuildStatements([]byte(inputString))
+	_, _, err := AqueryBuildStatements([]byte(inputString))
 	assertError(t, err, `Expect 1 input and 1 output to symlink action, got: input ["file"], output ["symlink" "other_symlink"]`)
 }
 
@@ -1045,7 +1146,7 @@
   }]
 }`
 
-	actual, err := AqueryBuildStatements([]byte(inputString))
+	actual, _, err := AqueryBuildStatements([]byte(inputString))
 
 	if err != nil {
 		t.Errorf("Unexpected error %q", err)
@@ -1091,7 +1192,7 @@
   }]
 }`
 
-	_, err := AqueryBuildStatements([]byte(inputString))
+	_, _, err := AqueryBuildStatements([]byte(inputString))
 	assertError(t, err, `Expect 1 output to template expand action, got: output []`)
 }
 
@@ -1211,7 +1312,7 @@
     "label": "python_binary"
   }]
 }`
-	actual, err := AqueryBuildStatements([]byte(inputString))
+	actual, _, err := AqueryBuildStatements([]byte(inputString))
 
 	if err != nil {
 		t.Errorf("Unexpected error %q", err)
@@ -1264,7 +1365,7 @@
     "label": "python_binary.zip"
   }]
 }`
-	_, err := AqueryBuildStatements([]byte(inputString))
+	_, _, err := AqueryBuildStatements([]byte(inputString))
 	assertError(t, err, `Expect 1+ input and 1 output to python zipper action, got: input [], output ["python_binary.zip"]`)
 }
 
@@ -1360,7 +1461,7 @@
     "parentId": 11
   }]
 }`
-	_, err := AqueryBuildStatements([]byte(inputString))
+	_, _, err := AqueryBuildStatements([]byte(inputString))
 	assertError(t, err, `Expect 1+ input and 1 output to python zipper action, got: input ["../bazel_tools/tools/zip/zipper/zipper" "python_binary.py"], output []`)
 }
 
diff --git a/bp2build/android_app_conversion_test.go b/bp2build/android_app_conversion_test.go
index 3824586..a216c9d 100644
--- a/bp2build/android_app_conversion_test.go
+++ b/bp2build/android_app_conversion_test.go
@@ -74,7 +74,8 @@
         package_name: "com.google",
         resource_dirs: ["resa", "resb"],
         manifest: "manifest/AndroidManifest.xml",
-        static_libs: ["static_lib_dep"]
+        static_libs: ["static_lib_dep"],
+        java_version: "7",
 }
 `,
 		expectedBazelTargets: []string{
@@ -87,6 +88,7 @@
     ]`,
 				"custom_package": `"com.google"`,
 				"deps":           `[":static_lib_dep"]`,
+				"javacopts":      `["-source 1.7 -target 1.7"]`,
 			}),
 		}})
 }
diff --git a/bp2build/java_binary_host_conversion_test.go b/bp2build/java_binary_host_conversion_test.go
index 4fc07e0..d7a76a8 100644
--- a/bp2build/java_binary_host_conversion_test.go
+++ b/bp2build/java_binary_host_conversion_test.go
@@ -52,6 +52,7 @@
     jni_libs: ["jni-lib-1"],
     javacflags: ["-Xdoclint:all/protected"],
     bazel_module: { bp2build_available: true },
+    java_version: "8",
 }`,
 		expectedBazelTargets: []string{
 			makeBazelTarget("java_binary", "java-binary-host-1", attrNameToString{
@@ -59,7 +60,10 @@
 				"main_class": `"com.android.test.MainClass"`,
 				"deps":       `["//other:jni-lib-1"]`,
 				"jvm_flags":  `["-Djava.library.path=$${RUNPATH}other"]`,
-				"javacopts":  `["-Xdoclint:all/protected"]`,
+				"javacopts": `[
+        "-Xdoclint:all/protected",
+        "-source 1.8 -target 1.8",
+    ]`,
 				"target_compatible_with": `select({
         "//build/bazel/platforms/os:android": ["@platforms//:incompatible"],
         "//conditions:default": [],
diff --git a/bp2build/java_library_conversion_test.go b/bp2build/java_library_conversion_test.go
index ccc52ef..3b66369 100644
--- a/bp2build/java_library_conversion_test.go
+++ b/bp2build/java_library_conversion_test.go
@@ -158,6 +158,22 @@
 	})
 }
 
+func TestJavaLibraryJavaVersion(t *testing.T) {
+	runJavaLibraryTestCase(t, bp2buildTestCase{
+		blueprint: `java_library {
+    name: "java-lib-1",
+    srcs: ["a.java"],
+    java_version: "11",
+}`,
+		expectedBazelTargets: []string{
+			makeBazelTarget("java_library", "java-lib-1", attrNameToString{
+				"srcs":      `["a.java"]`,
+				"javacopts": `["-source 11 -target 11"]`,
+			}),
+		},
+	})
+}
+
 func TestJavaLibraryErrorproneJavacflagsEnabledManually(t *testing.T) {
 	runJavaLibraryTestCase(t, bp2buildTestCase{
 		blueprint: `java_library {
diff --git a/bp2build/java_library_host_conversion_test.go b/bp2build/java_library_host_conversion_test.go
index 73abdd2..83cc551 100644
--- a/bp2build/java_library_host_conversion_test.go
+++ b/bp2build/java_library_host_conversion_test.go
@@ -43,6 +43,7 @@
     name: "java-lib-host-2",
     srcs: ["c.java"],
     bazel_module: { bp2build_available: true },
+    java_version: "9",
 }`,
 		expectedBazelTargets: []string{
 			makeBazelTarget("java_library", "java-lib-host-1", attrNameToString{
@@ -54,7 +55,8 @@
     })`,
 			}),
 			makeBazelTarget("java_library", "java-lib-host-2", attrNameToString{
-				"srcs": `["c.java"]`,
+				"javacopts": `["-source 1.9 -target 1.9"]`,
+				"srcs":      `["c.java"]`,
 				"target_compatible_with": `select({
         "//build/bazel/platforms/os:android": ["@platforms//:incompatible"],
         "//conditions:default": [],
diff --git a/bp2build/java_plugin_conversion_test.go b/bp2build/java_plugin_conversion_test.go
index c2a2182..dc763e7 100644
--- a/bp2build/java_plugin_conversion_test.go
+++ b/bp2build/java_plugin_conversion_test.go
@@ -39,6 +39,7 @@
     libs: ["java-lib-1"],
     static_libs: ["java-lib-2"],
     bazel_module: { bp2build_available: true },
+    java_version: "7",
 }
 
 java_library {
@@ -66,6 +67,7 @@
         "a.java",
         "b.java",
     ]`,
+				"javacopts": `["-source 1.7 -target 1.7"]`,
 			}),
 		},
 	})
diff --git a/bp2build/java_proto_conversion_test.go b/bp2build/java_proto_conversion_test.go
index 67f8044..c6feeb8 100644
--- a/bp2build/java_proto_conversion_test.go
+++ b/bp2build/java_proto_conversion_test.go
@@ -102,6 +102,7 @@
 		blueprint: `java_library_static {
     name: "java-protos",
     srcs: ["a.proto"],
+    java_version: "7",
 }
 `,
 		expectedBazelTargets: []string{
@@ -115,7 +116,8 @@
 					"deps": `[":java-protos_proto"]`,
 				}),
 			makeBazelTarget("java_library", "java-protos", attrNameToString{
-				"exports": `[":java-protos_java_proto_lite"]`,
+				"exports":   `[":java-protos_java_proto_lite"]`,
+				"javacopts": `["-source 1.7 -target 1.7"]`,
 			}),
 		},
 	})
diff --git a/cc/Android.bp b/cc/Android.bp
index b105e7c..60d329e 100644
--- a/cc/Android.bp
+++ b/cc/Android.bp
@@ -15,6 +15,7 @@
         "soong-etc",
         "soong-fuzz",
         "soong-genrule",
+        "soong-multitree",
         "soong-snapshot",
         "soong-tradefed",
     ],
@@ -65,6 +66,7 @@
         "library.go",
         "library_headers.go",
         "library_sdk_member.go",
+        "library_stub.go",
         "native_bridge_sdk_trait.go",
         "object.go",
         "test.go",
@@ -94,6 +96,7 @@
         "gen_test.go",
         "genrule_test.go",
         "library_headers_test.go",
+        "library_stub_test.go",
         "library_test.go",
         "object_test.go",
         "prebuilt_test.go",
diff --git a/cc/builder.go b/cc/builder.go
index 525b1a1..107cd58 100644
--- a/cc/builder.go
+++ b/cc/builder.go
@@ -855,13 +855,24 @@
 	deps = append(deps, crtBegin...)
 	deps = append(deps, crtEnd...)
 
+	var depFile android.WritablePath
+	var depFileLdFlags string
+	depsType := blueprint.DepsNone
+	if !ctx.Windows() && !ctx.Darwin() {
+		// lld only supports --dependency-file for elf files
+		depFile = outputFile.ReplaceExtension(ctx, "d")
+		depFileLdFlags = " -Wl,--dependency-file=" + depFile.String()
+		depsType = blueprint.DepsGCC
+		implicitOutputs = append(implicitOutputs, depFile)
+	}
+
 	rule := ld
 	args := map[string]string{
 		"ldCmd":         ldCmd,
 		"crtBegin":      strings.Join(crtBegin.Strings(), " "),
 		"libFlags":      strings.Join(libFlagsList, " "),
 		"extraLibFlags": flags.extraLibFlags,
-		"ldFlags":       flags.globalLdFlags + " " + flags.localLdFlags,
+		"ldFlags":       flags.globalLdFlags + " " + flags.localLdFlags + depFileLdFlags,
 		"crtEnd":        strings.Join(crtEnd.Strings(), " "),
 	}
 	if ctx.Config().UseRBE() && ctx.Config().IsEnvTrue("RBE_CXX_LINKS") {
@@ -872,6 +883,8 @@
 
 	ctx.Build(pctx, android.BuildParams{
 		Rule:            rule,
+		Deps:            depsType,
+		Depfile:         depFile,
 		Description:     "link " + outputFile.Base(),
 		Output:          outputFile,
 		ImplicitOutputs: implicitOutputs,
@@ -1025,18 +1038,33 @@
 
 	ldCmd := "${config.ClangBin}/clang++"
 
+	var implicitOutputs android.WritablePaths
+	var depFile android.WritablePath
+	var depFileLdFlags string
+	depsType := blueprint.DepsNone
+	if !ctx.Windows() && !ctx.Darwin() {
+		// lld only supports --dependency-file for elf files
+		depFile = outputFile.ReplaceExtension(ctx, "d")
+		depFileLdFlags = " -Wl,--dependency-file=" + depFile.String()
+		depsType = blueprint.DepsGCC
+		implicitOutputs = append(implicitOutputs, depFile)
+	}
+
 	rule := partialLd
 	args := map[string]string{
 		"ldCmd":   ldCmd,
-		"ldFlags": flags.globalLdFlags + " " + flags.localLdFlags,
+		"ldFlags": flags.globalLdFlags + " " + flags.localLdFlags + depFileLdFlags,
 	}
 	if ctx.Config().UseRBE() && ctx.Config().IsEnvTrue("RBE_CXX_LINKS") {
 		rule = partialLdRE
 		args["inCommaList"] = strings.Join(objFiles.Strings(), ",")
 		args["implicitInputs"] = strings.Join(deps.Strings(), ",")
+		args["implicitOutputs"] = strings.Join(implicitOutputs.Strings(), ",")
 	}
 	ctx.Build(pctx, android.BuildParams{
 		Rule:        rule,
+		Deps:        depsType,
+		Depfile:     depFile,
 		Description: "link " + outputFile.Base(),
 		Output:      outputFile,
 		Inputs:      objFiles,
diff --git a/cc/config/global.go b/cc/config/global.go
index 3caf327..dc6310c 100644
--- a/cc/config/global.go
+++ b/cc/config/global.go
@@ -286,8 +286,8 @@
 
 	// prebuilts/clang default settings.
 	ClangDefaultBase         = "prebuilts/clang/host"
-	ClangDefaultVersion      = "clang-r450784d"
-	ClangDefaultShortVersion = "14.0.6"
+	ClangDefaultVersion      = "clang-r450784e"
+	ClangDefaultShortVersion = "14.0.7"
 
 	// Directories with warnings from Android.bp files.
 	WarningAllowedProjects = []string{
diff --git a/cc/libbuildversion/tests/Android.bp b/cc/libbuildversion/tests/Android.bp
index 0e97fed..c616a33 100644
--- a/cc/libbuildversion/tests/Android.bp
+++ b/cc/libbuildversion/tests/Android.bp
@@ -35,6 +35,16 @@
                 dir: "host/",
             },
         },
+        linux_musl_x86: {
+            dist: {
+                dir: "host32/",
+            },
+        },
+        linux_musl_x86_64: {
+            dist: {
+                dir: "host/",
+            },
+        },
         linux_glibc_x86: {
             dist: {
                 dir: "host32/",
diff --git a/cc/library_stub.go b/cc/library_stub.go
new file mode 100644
index 0000000..4d0148d
--- /dev/null
+++ b/cc/library_stub.go
@@ -0,0 +1,163 @@
+// Copyright 2021 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cc
+
+import (
+	"android/soong/android"
+	"android/soong/multitree"
+)
+
+func init() {
+	RegisterLibraryStubBuildComponents(android.InitRegistrationContext)
+}
+
+func RegisterLibraryStubBuildComponents(ctx android.RegistrationContext) {
+	// cc_api_stub_library shares a lot of ndk_library, and this will be refactored later
+	ctx.RegisterModuleType("cc_api_stub_library", CcApiStubLibraryFactory)
+	ctx.RegisterModuleType("cc_api_contribution", CcApiContributionFactory)
+}
+
+func CcApiStubLibraryFactory() android.Module {
+	module, decorator := NewLibrary(android.DeviceSupported)
+	apiStubDecorator := &apiStubDecorator{
+		libraryDecorator: decorator,
+	}
+	apiStubDecorator.BuildOnlyShared()
+
+	module.compiler = apiStubDecorator
+	module.linker = apiStubDecorator
+	module.installer = nil
+	module.library = apiStubDecorator
+	module.Properties.HideFromMake = true // TODO: remove
+
+	android.InitAndroidArchModule(module, android.DeviceSupported, android.MultilibBoth)
+	module.AddProperties(&module.Properties,
+		&apiStubDecorator.properties,
+		&apiStubDecorator.MutatedProperties,
+		&apiStubDecorator.apiStubLibraryProperties)
+	return module
+}
+
+type apiStubLiraryProperties struct {
+	Imported_includes []string `android:"path"`
+}
+
+type apiStubDecorator struct {
+	*libraryDecorator
+	properties               libraryProperties
+	apiStubLibraryProperties apiStubLiraryProperties
+}
+
+func (compiler *apiStubDecorator) stubsVersions(ctx android.BaseMutatorContext) []string {
+	firstVersion := String(compiler.properties.First_version)
+	return ndkLibraryVersions(ctx, android.ApiLevelOrPanic(ctx, firstVersion))
+}
+
+func (decorator *apiStubDecorator) compile(ctx ModuleContext, flags Flags, deps PathDeps) Objects {
+	if decorator.stubsVersion() == "" {
+		decorator.setStubsVersion("current")
+	} // TODO: fix
+	symbolFile := String(decorator.properties.Symbol_file)
+	nativeAbiResult := parseNativeAbiDefinition(ctx, symbolFile,
+		android.ApiLevelOrPanic(ctx, decorator.stubsVersion()),
+		"")
+	return compileStubLibrary(ctx, flags, nativeAbiResult.stubSrc)
+}
+
+func (decorator *apiStubDecorator) link(ctx ModuleContext, flags Flags, deps PathDeps, objects Objects) android.Path {
+	decorator.reexportDirs(android.PathsForModuleSrc(ctx, decorator.apiStubLibraryProperties.Imported_includes)...)
+	return decorator.libraryDecorator.link(ctx, flags, deps, objects)
+}
+
+func init() {
+	pctx.HostBinToolVariable("gen_api_surface_build_files", "gen_api_surface_build_files")
+}
+
+type CcApiContribution struct {
+	android.ModuleBase
+	properties ccApiContributionProperties
+}
+
+type ccApiContributionProperties struct {
+	Symbol_file        *string `android:"path"`
+	First_version      *string
+	Export_include_dir *string
+}
+
+func CcApiContributionFactory() android.Module {
+	module := &CcApiContribution{}
+	module.AddProperties(&module.properties)
+	android.InitAndroidModule(module)
+	return module
+}
+
+// Do some simple validations
+// Majority of the build rules will be created in the ctx of the api surface this module contributes to
+func (contrib *CcApiContribution) GenerateAndroidBuildActions(ctx android.ModuleContext) {
+	if contrib.properties.Symbol_file == nil {
+		ctx.PropertyErrorf("symbol_file", "%v does not have symbol file", ctx.ModuleName())
+	}
+	if contrib.properties.First_version == nil {
+		ctx.PropertyErrorf("first_version", "%v does not have first_version for stub variants", ctx.ModuleName())
+	}
+}
+
+// Path is out/soong/.export/ but will be different in final multi-tree layout
+func outPathApiSurface(ctx android.ModuleContext, myModuleName string, pathComponent string) android.OutputPath {
+	return android.PathForOutput(ctx, ".export", ctx.ModuleName(), myModuleName, pathComponent)
+}
+
+func (contrib *CcApiContribution) CopyFilesWithTag(apiSurfaceContext android.ModuleContext) map[string]android.Paths {
+	// copy map.txt for now
+	// hardlinks cannot be created since nsjail creates a different mountpoint for out/
+	myDir := apiSurfaceContext.OtherModuleDir(contrib)
+	genMapTxt := outPathApiSurface(apiSurfaceContext, contrib.Name(), String(contrib.properties.Symbol_file))
+	apiSurfaceContext.Build(pctx, android.BuildParams{
+		Rule:        android.Cp,
+		Description: "import map.txt file",
+		Input:       android.PathForSource(apiSurfaceContext, myDir, String(contrib.properties.Symbol_file)),
+		Output:      genMapTxt,
+	})
+
+	outputs := make(map[string]android.Paths)
+	outputs["map"] = []android.Path{genMapTxt}
+
+	if contrib.properties.Export_include_dir != nil {
+		includeDir := android.PathForSource(apiSurfaceContext, myDir, String(contrib.properties.Export_include_dir))
+		outputs["export_include_dir"] = []android.Path{includeDir}
+	}
+	return outputs
+}
+
+var _ multitree.ApiContribution = (*CcApiContribution)(nil)
+
+/*
+func (contrib *CcApiContribution) GenerateBuildFiles(apiSurfaceContext android.ModuleContext) android.Paths {
+	genAndroidBp := outPathApiSurface(apiSurfaceContext, contrib.Name(), "Android.bp")
+
+	// generate Android.bp
+	apiSurfaceContext.Build(pctx, android.BuildParams{
+		Rule:        genApiSurfaceBuildFiles,
+		Description: "generate API surface build files",
+		Outputs:     []android.WritablePath{genAndroidBp},
+		Args: map[string]string{
+			"name":          contrib.Name() + "." + apiSurfaceContext.ModuleName(), //e.g. liblog.ndk
+			"symbol_file":   String(contrib.properties.Symbol_file),
+			"first_version": String(contrib.properties.First_version),
+		},
+	})
+	return []android.Path{genAndroidBp}
+}
+*/
diff --git a/cc/library_stub_test.go b/cc/library_stub_test.go
new file mode 100644
index 0000000..15b56d2
--- /dev/null
+++ b/cc/library_stub_test.go
@@ -0,0 +1,108 @@
+// Copyright 2021 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cc
+
+import (
+	_ "fmt"
+	_ "sort"
+
+	"testing"
+
+	"android/soong/android"
+	"android/soong/multitree"
+)
+
+func TestCcApiStubLibraryOutputFiles(t *testing.T) {
+	bp := `
+		cc_api_stub_library {
+			name: "foo",
+			symbol_file: "foo.map.txt",
+			first_version: "29",
+		}
+	`
+	result := prepareForCcTest.RunTestWithBp(t, bp)
+	outputs := result.ModuleForTests("foo", "android_arm64_armv8-a_shared").AllOutputs()
+	expected_file_suffixes := []string{".c", "stub.map", ".o", ".so"}
+	for _, expected_file_suffix := range expected_file_suffixes {
+		android.AssertBoolEquals(t, expected_file_suffix+" file not found in output", true, android.SuffixInList(outputs, expected_file_suffix))
+	}
+}
+
+func TestCcApiStubLibraryVariants(t *testing.T) {
+	bp := `
+		cc_api_stub_library {
+			name: "foo",
+			symbol_file: "foo.map.txt",
+			first_version: "29",
+		}
+	`
+	result := prepareForCcTest.RunTestWithBp(t, bp)
+	variants := result.ModuleVariantsForTests("foo")
+	expected_variants := []string{"29", "30", "S", "Tiramisu"} //TODO: make this test deterministic by using fixtures
+	for _, expected_variant := range expected_variants {
+		android.AssertBoolEquals(t, expected_variant+" variant not found in foo", true, android.SubstringInList(variants, expected_variant))
+	}
+}
+
+func TestCcLibraryUsesCcApiStubLibrary(t *testing.T) {
+	bp := `
+		cc_api_stub_library {
+			name: "foo",
+			symbol_file: "foo.map.txt",
+			first_version: "29",
+		}
+		cc_library {
+			name: "foo_user",
+			shared_libs: [
+				"foo#29",
+			],
+		}
+
+	`
+	prepareForCcTest.RunTestWithBp(t, bp)
+}
+
+func TestApiSurfaceOutputs(t *testing.T) {
+	bp := `
+		api_surface {
+			name: "mysdk",
+			contributions: [
+				"foo",
+			],
+		}
+
+		cc_api_contribution {
+			name: "foo",
+			symbol_file: "foo.map.txt",
+			first_version: "29",
+		}
+	`
+	result := android.GroupFixturePreparers(
+		prepareForCcTest,
+		multitree.PrepareForTestWithApiSurface,
+	).RunTestWithBp(t, bp)
+	mysdk := result.ModuleForTests("mysdk", "")
+
+	actual_surface_inputs := mysdk.Rule("phony").BuildParams.Inputs.Strings()
+	expected_file_suffixes := []string{"mysdk/foo/foo.map.txt"}
+	for _, expected_file_suffix := range expected_file_suffixes {
+		android.AssertBoolEquals(t, expected_file_suffix+" file not found in input", true, android.SuffixInList(actual_surface_inputs, expected_file_suffix))
+	}
+
+	// check args/inputs to rule
+	/*api_surface_gen_rule_args := result.ModuleForTests("mysdk", "").Rule("genApiSurfaceBuildFiles").Args
+	android.AssertStringEquals(t, "name", "foo.mysdk", api_surface_gen_rule_args["name"])
+	android.AssertStringEquals(t, "symbol_file", "foo.map.txt", api_surface_gen_rule_args["symbol_file"])*/
+}
diff --git a/cc/ndk_library.go b/cc/ndk_library.go
index 5ef41ea..c031b14 100644
--- a/cc/ndk_library.go
+++ b/cc/ndk_library.go
@@ -93,7 +93,7 @@
 type libraryProperties struct {
 	// Relative path to the symbol map.
 	// An example file can be seen here: TODO(danalbert): Make an example.
-	Symbol_file *string
+	Symbol_file *string `android:"path"`
 
 	// The first API level a library was available. A library will be generated
 	// for every API level beginning with this one.
diff --git a/cc/testing.go b/cc/testing.go
index 32f7c60..ecdae8b 100644
--- a/cc/testing.go
+++ b/cc/testing.go
@@ -29,6 +29,7 @@
 	RegisterBinaryBuildComponents(ctx)
 	RegisterLibraryBuildComponents(ctx)
 	RegisterLibraryHeadersBuildComponents(ctx)
+	RegisterLibraryStubBuildComponents(ctx)
 
 	ctx.RegisterModuleType("cc_benchmark", BenchmarkFactory)
 	ctx.RegisterModuleType("cc_object", ObjectFactory)
diff --git a/dexpreopt/class_loader_context.go b/dexpreopt/class_loader_context.go
index 36513b6..d0a6a39 100644
--- a/dexpreopt/class_loader_context.go
+++ b/dexpreopt/class_loader_context.go
@@ -678,6 +678,9 @@
 	jClcMap := make(jsonClassLoaderContextMap)
 	for sdkVer, clcs := range clcMap {
 		sdkVerStr := fmt.Sprintf("%d", sdkVer)
+		if sdkVer == AnySdkVersion {
+			sdkVerStr = "any"
+		}
 		jClcMap[sdkVerStr] = toJsonClassLoaderContextRec(clcs)
 	}
 	return jClcMap
diff --git a/dexpreopt/class_loader_context_test.go b/dexpreopt/class_loader_context_test.go
index 5d3a9d9..614681f 100644
--- a/dexpreopt/class_loader_context_test.go
+++ b/dexpreopt/class_loader_context_test.go
@@ -389,6 +389,38 @@
 	})
 }
 
+// Test that CLC is correctly serialized to JSON.
+func TestCLCtoJSON(t *testing.T) {
+	ctx := testContext()
+	optional := false
+	implicit := true
+	m := make(ClassLoaderContextMap)
+	m.AddContext(ctx, 28, "a", optional, implicit, buildPath(ctx, "a"), installPath(ctx, "a"), nil)
+	m.AddContext(ctx, AnySdkVersion, "b", optional, implicit, buildPath(ctx, "b"), installPath(ctx, "b"), nil)
+	android.AssertStringEquals(t, "output CLCM ", `{
+  "28": [
+    {
+      "Name": "a",
+      "Optional": false,
+      "Implicit": true,
+      "Host": "out/soong/a.jar",
+      "Device": "/system/a.jar",
+      "Subcontexts": []
+    }
+  ],
+  "any": [
+    {
+      "Name": "b",
+      "Optional": false,
+      "Implicit": true,
+      "Host": "out/soong/b.jar",
+      "Device": "/system/b.jar",
+      "Subcontexts": []
+    }
+  ]
+}`, m.Dump())
+}
+
 func checkError(t *testing.T, have error, want string) {
 	if have == nil {
 		t.Errorf("\nwant error: '%s'\nhave: none", want)
diff --git a/dexpreopt/config.go b/dexpreopt/config.go
index 153b025..ab9e418 100644
--- a/dexpreopt/config.go
+++ b/dexpreopt/config.go
@@ -36,8 +36,6 @@
 
 	PreoptWithUpdatableBcp bool // If updatable boot jars are included in dexpreopt or not.
 
-	UseArtImage bool // use the art image (use other boot class path dex files without image)
-
 	HasSystemOther        bool     // store odex files that match PatternsOnSystemOther on the system_other partition
 	PatternsOnSystemOther []string // patterns (using '%' to denote a prefix match) to put odex on the system_other partition
 
diff --git a/java/config/config.go b/java/config/config.go
index 46c91a2..d744002 100644
--- a/java/config/config.go
+++ b/java/config/config.go
@@ -68,6 +68,11 @@
 		"-J-XX:+TieredCompilation",
 		"-J-XX:TieredStopAtLevel=1",
 	}
+	dexerJavaVmFlagsList = []string{
+		`-JXX:OnError="cat hs_err_pid%p.log"`,
+		"-JXX:CICompilerCount=6",
+		"-JXX:+UseDynamicNumberOfGCThreads",
+	}
 )
 
 func init() {
@@ -83,19 +88,14 @@
 
 	// D8 invocations are shorter lived, so we restrict their JIT tiering relative to R8.
 	// Note that the `-JXX` prefix syntax is specific to the R8/D8 invocation wrappers.
-	exportedVars.ExportStringListStaticVariable("D8Flags", []string{
-		`-JXX:OnError="cat hs_err_pid%p.log"`,
-		"-JXX:CICompilerCount=6",
-		"-JXX:+UseDynamicNumberOfGCThreads",
+	exportedVars.ExportStringListStaticVariable("D8Flags", append([]string{
+		"-JXmx2048M",
 		"-JXX:+TieredCompilation",
 		"-JXX:TieredStopAtLevel=1",
-	})
-
-	exportedVars.ExportStringListStaticVariable("R8Flags", []string{
-		`-JXX:OnError="cat hs_err_pid%p.log"`,
-		"-JXX:CICompilerCount=6",
-		"-JXX:+UseDynamicNumberOfGCThreads",
-	})
+	}, dexerJavaVmFlagsList...))
+	exportedVars.ExportStringListStaticVariable("R8Flags", append([]string{
+		"-JXmx2048M",
+	}, dexerJavaVmFlagsList...))
 
 	exportedVars.ExportStringListStaticVariable("CommonJdkFlags", []string{
 		`-Xmaxerrs 9999999`,
diff --git a/java/config/makevars.go b/java/config/makevars.go
index bc6848f..273aca0 100644
--- a/java/config/makevars.go
+++ b/java/config/makevars.go
@@ -43,9 +43,10 @@
 	ctx.Strict("JAVADOC", "${JavadocCmd}")
 	ctx.Strict("COMMON_JDK_FLAGS", "${CommonJdkFlags}")
 
-	ctx.Strict("DX", "${D8Cmd}")
-	ctx.Strict("DX_COMMAND", "${D8Cmd} -JXms16M -JXmx2048M")
-	ctx.Strict("R8_COMPAT_PROGUARD", "${R8Cmd}")
+	ctx.Strict("D8", "${D8Cmd}")
+	ctx.Strict("R8", "${R8Cmd}")
+	ctx.Strict("D8_COMMAND", "${D8Cmd} ${D8Flags}")
+	ctx.Strict("R8_COMMAND", "${R8Cmd} ${R8Flags}")
 
 	ctx.Strict("TURBINE", "${TurbineJar}")
 
@@ -78,9 +79,6 @@
 	ctx.Strict("CLASS2NONSDKLIST", "${Class2NonSdkList}")
 	ctx.Strict("HIDDENAPI", "${HiddenAPI}")
 
-	ctx.Strict("D8_FLAGS", "${D8Flags}")
-	ctx.Strict("R8_FLAGS", "${R8Flags}")
-
 	ctx.Strict("AIDL", "${AidlCmd}")
 	ctx.Strict("AAPT2", "${Aapt2Cmd}")
 	ctx.Strict("ZIPALIGN", "${ZipAlign}")
diff --git a/java/dexpreopt.go b/java/dexpreopt.go
index 7c5f055..0adaf99 100644
--- a/java/dexpreopt.go
+++ b/java/dexpreopt.go
@@ -259,10 +259,6 @@
 	isSystemServerJar := global.AllSystemServerJars(ctx).ContainsJar(moduleName(ctx))
 
 	bootImage := defaultBootImageConfig(ctx)
-	if global.UseArtImage {
-		bootImage = artBootImageConfig(ctx)
-	}
-
 	dexFiles, dexLocations := bcpForDexpreopt(ctx, global.PreoptWithUpdatableBcp)
 
 	targets := ctx.MultiTargets()
diff --git a/java/dexpreopt_bootjars.go b/java/dexpreopt_bootjars.go
index 3d91aec..7c4da3e 100644
--- a/java/dexpreopt_bootjars.go
+++ b/java/dexpreopt_bootjars.go
@@ -213,12 +213,6 @@
 // writes out a few DEXPREOPT_IMAGE_* variables for Make; these variables contain boot image names,
 // paths and so on.
 //
-// 2.5. JIT-Zygote configuration
-// -----------------------------
-//
-// One special configuration is JIT-Zygote build, when the primary ART image is used for compiling
-// apps instead of the Framework boot image extension (see DEXPREOPT_USE_ART_IMAGE and UseArtImage).
-//
 
 var artApexNames = []string{
 	"com.android.art",
@@ -938,11 +932,8 @@
 		ctx.Strict("DEXPREOPT_BOOTCLASSPATH_DEX_LOCATIONS", strings.Join(dexLocations, " "))
 
 		var imageNames []string
-		// TODO: the primary ART boot image should not be exposed to Make, as it is installed in a
-		// different way as a part of the ART APEX. However, there is a special JIT-Zygote build
-		// configuration which uses the primary ART image instead of the Framework boot image
-		// extension, and it relies on the ART image being exposed to Make. To fix this, it is
-		// necessary to rework the logic in makefiles.
+		// The primary ART boot image is exposed to Make for testing (gtests) and benchmarking
+		// (golem) purposes.
 		for _, current := range append(d.otherImages, image) {
 			imageNames = append(imageNames, current.name)
 			for _, variant := range current.variants {
diff --git a/java/hiddenapi.go b/java/hiddenapi.go
index 3af5f1c..cf9c7ad 100644
--- a/java/hiddenapi.go
+++ b/java/hiddenapi.go
@@ -65,6 +65,8 @@
 type hiddenAPIModule interface {
 	android.Module
 	hiddenAPIIntf
+
+	MinSdkVersion(ctx android.EarlyModuleContext) android.SdkSpec
 }
 
 type hiddenAPIIntf interface {
@@ -148,7 +150,7 @@
 	// Create a copy of the dex jar which has been encoded with hiddenapi flags.
 	flagsCSV := hiddenAPISingletonPaths(ctx).flags
 	outputDir := android.PathForModuleOut(ctx, "hiddenapi").OutputPath
-	encodedDex := hiddenAPIEncodeDex(ctx, dexJar, flagsCSV, uncompressDex, outputDir)
+	encodedDex := hiddenAPIEncodeDex(ctx, dexJar, flagsCSV, uncompressDex, android.SdkSpecNone, outputDir)
 
 	// Use the encoded dex jar from here onwards.
 	return encodedDex
@@ -246,7 +248,7 @@
 // The encode dex rule requires unzipping, encoding and rezipping the classes.dex files along with
 // all the resources from the input jar. It also ensures that if it was uncompressed in the input
 // it stays uncompressed in the output.
-func hiddenAPIEncodeDex(ctx android.ModuleContext, dexInput, flagsCSV android.Path, uncompressDex bool, outputDir android.OutputPath) android.OutputPath {
+func hiddenAPIEncodeDex(ctx android.ModuleContext, dexInput, flagsCSV android.Path, uncompressDex bool, minSdkVersion android.SdkSpec, outputDir android.OutputPath) android.OutputPath {
 
 	// The output file has the same name as the input file and is in the output directory.
 	output := outputDir.Join(ctx, dexInput.Base())
@@ -274,6 +276,15 @@
 		hiddenapiFlags = "--no-force-assign-all"
 	}
 
+	// If the library is targeted for Q and/or R then make sure that they do not
+	// have any S+ flags encoded as that will break the runtime.
+	minApiLevel := minSdkVersion.ApiLevel
+	if !minApiLevel.IsNone() {
+		if minApiLevel.LessThanOrEqualTo(android.ApiLevelOrPanic(ctx, "R")) {
+			hiddenapiFlags = hiddenapiFlags + " --max-hiddenapi-level=max-target-r"
+		}
+	}
+
 	ctx.Build(pctx, android.BuildParams{
 		Rule:        hiddenAPIEncodeDexRule,
 		Description: "hiddenapi encode dex",
diff --git a/java/hiddenapi_modular.go b/java/hiddenapi_modular.go
index 534a814..c90b2ff 100644
--- a/java/hiddenapi_modular.go
+++ b/java/hiddenapi_modular.go
@@ -1104,7 +1104,7 @@
 	for _, name := range android.SortedStringKeys(bootDexInfoByModule) {
 		bootDexInfo := bootDexInfoByModule[name]
 		unencodedDex := bootDexInfo.path
-		encodedDex := hiddenAPIEncodeDex(ctx, unencodedDex, allFlagsCSV, bootDexInfo.uncompressDex, outputDir)
+		encodedDex := hiddenAPIEncodeDex(ctx, unencodedDex, allFlagsCSV, bootDexInfo.uncompressDex, bootDexInfo.minSdkVersion, outputDir)
 		encodedBootDexJarsByModule[name] = encodedDex
 	}
 
@@ -1188,6 +1188,9 @@
 
 	// Indicates whether the dex jar needs uncompressing before encoding.
 	uncompressDex bool
+
+	// The minimum sdk version that the dex jar will be used on.
+	minSdkVersion android.SdkSpec
 }
 
 // bootDexInfoByModule is a map from module name (as returned by module.Name()) to the boot dex
@@ -1213,6 +1216,7 @@
 		bootDexJarsByModule[module.Name()] = bootDexInfo{
 			path:          bootDexJar,
 			uncompressDex: *hiddenAPIModule.uncompressDex(),
+			minSdkVersion: hiddenAPIModule.MinSdkVersion(ctx),
 		}
 	}
 
diff --git a/java/java.go b/java/java.go
index b34d6de..4e7e14c 100644
--- a/java/java.go
+++ b/java/java.go
@@ -2089,6 +2089,11 @@
 	if m.properties.Javacflags != nil {
 		javacopts = append(javacopts, m.properties.Javacflags...)
 	}
+	if m.properties.Java_version != nil {
+		javaVersion := normalizeJavaVersion(ctx, *m.properties.Java_version).String()
+		javacopts = append(javacopts, fmt.Sprintf("-source %s -target %s", javaVersion, javaVersion))
+	}
+
 	epEnabled := m.properties.Errorprone.Enabled
 	//TODO(b/227504307) add configuration that depends on RUN_ERROR_PRONE environment variable
 	if Bool(epEnabled) {
diff --git a/java/sdk_library.go b/java/sdk_library.go
index c37ed1a..cd8e875 100644
--- a/java/sdk_library.go
+++ b/java/sdk_library.go
@@ -377,6 +377,9 @@
 	// List of Java libraries that will be in the classpath when building the implementation lib
 	Impl_only_libs []string `android:"arch_variant"`
 
+	// List of Java libraries that will included in the implementation lib.
+	Impl_only_static_libs []string `android:"arch_variant"`
+
 	// List of Java libraries that will be in the classpath when building stubs
 	Stub_only_libs []string `android:"arch_variant"`
 
@@ -1346,10 +1349,12 @@
 	visibility := childModuleVisibility(module.sdkLibraryProperties.Impl_library_visibility)
 
 	props := struct {
-		Name       *string
-		Visibility []string
-		Instrument bool
-		Libs       []string
+		Name           *string
+		Visibility     []string
+		Instrument     bool
+		Libs           []string
+		Static_libs    []string
+		Apex_available []string
 	}{
 		Name:       proptools.StringPtr(module.implLibraryModuleName()),
 		Visibility: visibility,
@@ -1358,6 +1363,12 @@
 		// Set the impl_only libs. Note that the module's "Libs" get appended as well, via the
 		// addition of &module.properties below.
 		Libs: module.sdkLibraryProperties.Impl_only_libs,
+		// Set the impl_only static libs. Note that the module's "static_libs" get appended as well, via the
+		// addition of &module.properties below.
+		Static_libs: module.sdkLibraryProperties.Impl_only_static_libs,
+		// Pass the apex_available settings down so that the impl library can be statically
+		// embedded within a library that is added to an APEX. Needed for updatable-media.
+		Apex_available: module.ApexAvailable(),
 	}
 
 	properties := []interface{}{
@@ -1814,8 +1825,9 @@
 		*javaSdkLibraries = append(*javaSdkLibraries, module.BaseModuleName())
 	}
 
-	// Add the impl_only_libs *after* we're done using the Libs prop in submodules.
+	// Add the impl_only_libs and impl_only_static_libs *after* we're done using them in submodules.
 	module.properties.Libs = append(module.properties.Libs, module.sdkLibraryProperties.Impl_only_libs...)
+	module.properties.Static_libs = append(module.properties.Static_libs, module.sdkLibraryProperties.Impl_only_static_libs...)
 }
 
 func (module *SdkLibrary) InitSdkLibraryProperties() {
@@ -2211,8 +2223,23 @@
 	return module.uniqueApexVariations()
 }
 
+// MinSdkVersion - Implements hiddenAPIModule
+func (module *SdkLibraryImport) MinSdkVersion(ctx android.EarlyModuleContext) android.SdkSpec {
+	return android.SdkSpecNone
+}
+
+var _ hiddenAPIModule = (*SdkLibraryImport)(nil)
+
 func (module *SdkLibraryImport) OutputFiles(tag string) (android.Paths, error) {
-	return module.commonOutputFiles(tag)
+	paths, err := module.commonOutputFiles(tag)
+	if paths != nil || err != nil {
+		return paths, err
+	}
+	if module.implLibraryModule != nil {
+		return module.implLibraryModule.OutputFiles(tag)
+	} else {
+		return nil, nil
+	}
 }
 
 func (module *SdkLibraryImport) GenerateAndroidBuildActions(ctx android.ModuleContext) {
diff --git a/mk2rbc/cmd/mk2rbc.go b/mk2rbc/cmd/mk2rbc.go
index e84eacd..cc83430 100644
--- a/mk2rbc/cmd/mk2rbc.go
+++ b/mk2rbc/cmd/mk2rbc.go
@@ -173,7 +173,7 @@
 	}
 	ok := true
 	for _, mkFile := range files {
-		ok = convertOne(mkFile) && ok
+		ok = convertOne(mkFile, []string{}) && ok
 	}
 
 	if *launcher != "" {
@@ -183,7 +183,7 @@
 		if *inputVariables == "" {
 			quit(fmt.Errorf("the product launcher requires an input variables file"))
 		}
-		if !convertOne(*inputVariables) {
+		if !convertOne(*inputVariables, []string{}) {
 			quit(fmt.Errorf("the product launcher input variables file failed to convert"))
 		}
 
@@ -201,7 +201,7 @@
 		if *inputVariables == "" {
 			quit(fmt.Errorf("the board launcher requires an input variables file"))
 		}
-		if !convertOne(*inputVariables) {
+		if !convertOne(*inputVariables, []string{}) {
 			quit(fmt.Errorf("the board launcher input variables file failed to convert"))
 		}
 		err := writeGenerated(*boardlauncher, mk2rbc.BoardLauncher(
@@ -310,9 +310,13 @@
 // the output hierarchy, or to the stdout.
 // Optionally, recursively convert the files this one includes by
 // $(call inherit-product) or an include statement.
-func convertOne(mkFile string) (ok bool) {
+func convertOne(mkFile string, loadStack []string) (ok bool) {
 	if v, ok := converted[mkFile]; ok {
-		return v != nil
+		if v == nil {
+			fmt.Fprintf(os.Stderr, "Cycle in load graph:\n%s\n%s\n\n", strings.Join(loadStack, "\n"), mkFile)
+			return false
+		}
+		return true
 	}
 	converted[mkFile] = nil
 	defer func() {
@@ -356,6 +360,7 @@
 			return false
 		}
 	}
+	loadStack = append(loadStack, mkFile)
 	ok = true
 	if *recurse {
 		for _, sub := range ss.SubConfigFiles() {
@@ -363,7 +368,7 @@
 			if _, err := os.Stat(sub); os.IsNotExist(err) {
 				continue
 			}
-			ok = convertOne(sub) && ok
+			ok = convertOne(sub, loadStack) && ok
 		}
 	}
 	converted[mkFile] = ss
diff --git a/mk2rbc/expr.go b/mk2rbc/expr.go
index 9266520..6a6eb46 100644
--- a/mk2rbc/expr.go
+++ b/mk2rbc/expr.go
@@ -741,8 +741,8 @@
 	return starlarkTypeUnknown
 }
 
-func (_ *badExpr) emitListVarCopy(_ *generationContext) {
-	panic("implement me")
+func (b *badExpr) emitListVarCopy(gctx *generationContext) {
+	b.emit(gctx)
 }
 
 func (b *badExpr) transform(transformer func(expr starlarkExpr) starlarkExpr) starlarkExpr {
diff --git a/mk2rbc/mk2rbc.go b/mk2rbc/mk2rbc.go
index 02b3d08..1041108 100644
--- a/mk2rbc/mk2rbc.go
+++ b/mk2rbc/mk2rbc.go
@@ -116,6 +116,7 @@
 	"subst":    &substCallParser{fname: "subst"},
 	"warning":  &makeControlFuncParser{name: baseName + ".mkwarning"},
 	"word":     &wordCallParser{},
+	"words":    &wordsCallParser{},
 	"wildcard": &simpleCallParser{name: baseName + ".expand_wildcard", returnType: starlarkTypeList},
 }
 
@@ -130,6 +131,14 @@
 	"foreach":                   &foreachCallNodeParser{},
 }
 
+// These look like variables, but are actually functions, and would give
+// undefined variable errors if we converted them as variables. Instead,
+// emit an error instead of converting them.
+var unsupportedFunctions = map[string]bool{
+	"local-generated-sources-dir": true,
+	"local-intermediates-dir":     true,
+}
+
 // These are functions that we don't implement conversions for, but
 // we allow seeing their definitions in the product config files.
 var ignoredDefines = map[string]bool{
@@ -562,9 +571,6 @@
 	if lhs.valueType() == starlarkTypeUnknown {
 		// Try to divine variable type from the RHS
 		asgn.value = ctx.parseMakeString(a, a.Value)
-		if xBad, ok := asgn.value.(*badExpr); ok {
-			return []starlarkNode{&exprNode{xBad}}
-		}
 		inferred_type := asgn.value.typ()
 		if inferred_type != starlarkTypeUnknown {
 			lhs.setValueType(inferred_type)
@@ -573,21 +579,19 @@
 	if lhs.valueType() == starlarkTypeList {
 		xConcat, xBad := ctx.buildConcatExpr(a)
 		if xBad != nil {
-			return []starlarkNode{&exprNode{expr: xBad}}
-		}
-		switch len(xConcat.items) {
-		case 0:
-			asgn.value = &listExpr{}
-		case 1:
-			asgn.value = xConcat.items[0]
-		default:
-			asgn.value = xConcat
+			asgn.value = xBad
+		} else {
+			switch len(xConcat.items) {
+			case 0:
+				asgn.value = &listExpr{}
+			case 1:
+				asgn.value = xConcat.items[0]
+			default:
+				asgn.value = xConcat
+			}
 		}
 	} else {
 		asgn.value = ctx.parseMakeString(a, a.Value)
-		if xBad, ok := asgn.value.(*badExpr); ok {
-			return []starlarkNode{&exprNode{expr: xBad}}
-		}
 	}
 
 	if asgn.lhs.valueType() == starlarkTypeString &&
@@ -817,35 +821,40 @@
 	//       rblf.inherit(handle, _e[0], _e[1])
 	//
 	var matchingPaths []string
-	varPath, ok := pathExpr.(*interpolateExpr)
-	if !ok {
+	var needsWarning = false
+	if interpolate, ok := pathExpr.(*interpolateExpr); ok {
+		pathPattern := []string{interpolate.chunks[0]}
+		for _, chunk := range interpolate.chunks[1:] {
+			if chunk != "" {
+				pathPattern = append(pathPattern, chunk)
+			}
+		}
+		if pathPattern[0] == "" && len(ctx.includeTops) > 0 {
+			// If pattern starts from the top. restrict it to the directories where
+			// we know inherit-product uses dynamically calculated path.
+			for _, p := range ctx.includeTops {
+				pathPattern[0] = p
+				matchingPaths = append(matchingPaths, ctx.findMatchingPaths(pathPattern)...)
+			}
+		} else {
+			matchingPaths = ctx.findMatchingPaths(pathPattern)
+		}
+		needsWarning = pathPattern[0] == "" && len(ctx.includeTops) == 0
+	} else if len(ctx.includeTops) > 0 {
+		for _, p := range ctx.includeTops {
+			matchingPaths = append(matchingPaths, ctx.findMatchingPaths([]string{p, ""})...)
+		}
+	} else {
 		return []starlarkNode{ctx.newBadNode(v, "inherit-product/include argument is too complex")}
 	}
 
-	pathPattern := []string{varPath.chunks[0]}
-	for _, chunk := range varPath.chunks[1:] {
-		if chunk != "" {
-			pathPattern = append(pathPattern, chunk)
-		}
-	}
-	if pathPattern[0] == "" && len(ctx.includeTops) > 0 {
-		// If pattern starts from the top. restrict it to the directories where
-		// we know inherit-product uses dynamically calculated path.
-		for _, p := range ctx.includeTops {
-			pathPattern[0] = p
-			matchingPaths = append(matchingPaths, ctx.findMatchingPaths(pathPattern)...)
-		}
-	} else {
-		matchingPaths = ctx.findMatchingPaths(pathPattern)
-	}
 	// Safeguard against $(call inherit-product,$(PRODUCT_PATH))
 	const maxMatchingFiles = 150
 	if len(matchingPaths) > maxMatchingFiles {
 		return []starlarkNode{ctx.newBadNode(v, "there are >%d files matching the pattern, please rewrite it", maxMatchingFiles)}
 	}
 
-	needsWarning := pathPattern[0] == "" && len(ctx.includeTops) == 0
-	res := inheritedDynamicModule{*varPath, []*moduleInfo{}, loadAlways, ctx.errorLocation(v), needsWarning}
+	res := inheritedDynamicModule{pathExpr, []*moduleInfo{}, loadAlways, ctx.errorLocation(v), needsWarning}
 	for _, p := range matchingPaths {
 		// A product configuration files discovered dynamically may attempt to inherit
 		// from another one which does not exist in this source tree. Prevent load errors
@@ -895,8 +904,9 @@
 	})
 }
 
-func (ctx *parseContext) handleInclude(v mkparser.Node, pathExpr starlarkExpr, loadAlways bool) []starlarkNode {
-	return ctx.handleSubConfig(v, pathExpr, loadAlways, func(im inheritedModule) starlarkNode {
+func (ctx *parseContext) handleInclude(v *mkparser.Directive) []starlarkNode {
+	loadAlways := v.Name[0] != '-'
+	return ctx.handleSubConfig(v, ctx.parseMakeString(v, v.Args), loadAlways, func(im inheritedModule) starlarkNode {
 		return &includeNode{im, loadAlways}
 	})
 }
@@ -1074,6 +1084,18 @@
 				return otherOperand
 			}
 		}
+		if otherOperand.typ() == starlarkTypeList {
+			fields := strings.Fields(stringOperand)
+			elements := make([]starlarkExpr, len(fields))
+			for i, s := range fields {
+				elements[i] = &stringLiteralExpr{literal: s}
+			}
+			return &eqExpr{
+				left:  otherOperand,
+				right: &listExpr{elements},
+				isEq:  isEq,
+			}
+		}
 		if intOperand, err := strconv.Atoi(strings.TrimSpace(stringOperand)); err == nil && otherOperand.typ() == starlarkTypeInt {
 			return &eqExpr{
 				left:  otherOperand,
@@ -1119,8 +1141,6 @@
 	switch call.name {
 	case baseName + ".filter":
 		return ctx.parseCompareFilterFuncResult(directive, call, value, isEq)
-	case baseName + ".expand_wildcard":
-		return ctx.parseCompareWildcardFuncResult(directive, call, value, !isEq), true
 	case baseName + ".findstring":
 		return ctx.parseCheckFindstringFuncResult(directive, call, value, !isEq), true
 	case baseName + ".strip":
@@ -1165,22 +1185,6 @@
 	}
 }
 
-func (ctx *parseContext) parseCompareWildcardFuncResult(directive *mkparser.Directive,
-	xCall *callExpr, xValue starlarkExpr, negate bool) starlarkExpr {
-	if !isEmptyString(xValue) {
-		return ctx.newBadExpr(directive, "wildcard result can be compared only to empty: %s", xValue)
-	}
-	callFunc := baseName + ".file_wildcard_exists"
-	if s, ok := xCall.args[0].(*stringLiteralExpr); ok && !strings.ContainsAny(s.literal, "*?{[") {
-		callFunc = baseName + ".file_exists"
-	}
-	var cc starlarkExpr = &callExpr{name: callFunc, args: xCall.args, returnType: starlarkTypeBool}
-	if !negate {
-		cc = &notExpr{cc}
-	}
-	return cc
-}
-
 func (ctx *parseContext) parseCheckFindstringFuncResult(directive *mkparser.Directive,
 	xCall *callExpr, xValue starlarkExpr, negate bool) starlarkExpr {
 	if isEmptyString(xValue) {
@@ -1268,6 +1272,12 @@
 		return ctx.newBadExpr(node, "reference is too complex: %s", refDump)
 	}
 
+	if name, _, ok := ctx.maybeParseFunctionCall(node, ref); ok {
+		if _, unsupported := unsupportedFunctions[name]; unsupported {
+			return ctx.newBadExpr(node, "%s is not supported", refDump)
+		}
+	}
+
 	// If it is a single word, it can be a simple variable
 	// reference or a function call
 	if len(words) == 1 && !isMakeControlFunc(refDump) && refDump != "shell" && refDump != "eval" {
@@ -1315,9 +1325,8 @@
 		} else {
 			return ctx.newBadExpr(node, "cannot handle invoking %s", name)
 		}
-	} else {
-		return ctx.newBadExpr(node, "cannot handle %s", refDump)
 	}
+	return ctx.newBadExpr(node, "cannot handle %s", refDump)
 }
 
 type simpleCallParser struct {
@@ -1593,6 +1602,16 @@
 		for _, n := range a.actions {
 			transformNode(n, transformer)
 		}
+	case *inheritNode:
+		if b, ok := a.module.(inheritedDynamicModule); ok {
+			b.path = b.path.transform(transformer)
+			a.module = b
+		}
+	case *includeNode:
+		if b, ok := a.module.(inheritedDynamicModule); ok {
+			b.path = b.path.transform(transformer)
+			a.module = b
+		}
 	}
 }
 
@@ -1643,9 +1662,11 @@
 	if len(words) != 2 {
 		return ctx.newBadExpr(node, "word function should have 2 arguments")
 	}
-	var index uint64 = 0
+	var index = 0
 	if words[0].Const() {
-		index, _ = strconv.ParseUint(strings.TrimSpace(words[0].Strings[0]), 10, 64)
+		if i, err := strconv.Atoi(strings.TrimSpace(words[0].Strings[0])); err == nil {
+			index = i
+		}
 	}
 	if index < 1 {
 		return ctx.newBadExpr(node, "word index should be constant positive integer")
@@ -1653,13 +1674,40 @@
 	words[1].TrimLeftSpaces()
 	words[1].TrimRightSpaces()
 	array := ctx.parseMakeString(node, words[1])
-	if xBad, ok := array.(*badExpr); ok {
-		return xBad
+	if bad, ok := array.(*badExpr); ok {
+		return bad
 	}
 	if array.typ() != starlarkTypeList {
-		array = &callExpr{object: array, name: "split", returnType: starlarkTypeList}
+		array = &callExpr{
+			name:       baseName + ".words",
+			args:       []starlarkExpr{array},
+			returnType: starlarkTypeList,
+		}
 	}
-	return &indexExpr{array, &intLiteralExpr{int(index - 1)}}
+	return &indexExpr{array, &intLiteralExpr{index - 1}}
+}
+
+type wordsCallParser struct{}
+
+func (p *wordsCallParser) parse(ctx *parseContext, node mkparser.Node, args *mkparser.MakeString) starlarkExpr {
+	args.TrimLeftSpaces()
+	args.TrimRightSpaces()
+	array := ctx.parseMakeString(node, args)
+	if bad, ok := array.(*badExpr); ok {
+		return bad
+	}
+	if array.typ() != starlarkTypeList {
+		array = &callExpr{
+			name:       baseName + ".words",
+			args:       []starlarkExpr{array},
+			returnType: starlarkTypeList,
+		}
+	}
+	return &callExpr{
+		name:       "len",
+		args:       []starlarkExpr{array},
+		returnType: starlarkTypeInt,
+	}
 }
 
 type firstOrLastwordCallParser struct {
@@ -1765,10 +1813,23 @@
 			}
 		case *mkparser.Comment:
 			return []starlarkNode{&commentNode{strings.TrimSpace("#" + n.Comment)}}
+		case *mkparser.Directive:
+			if n.Name == "include" || n.Name == "-include" {
+				return ctx.handleInclude(n)
+			}
+		case *mkparser.Variable:
+			// Technically inherit-product(-if-exists) don't need to be put inside
+			// an eval, but some makefiles do it, presumably because they copy+pasted
+			// from a $(eval include ...)
+			if name, _, ok := ctx.maybeParseFunctionCall(n, n.Name); ok {
+				if name == "inherit-product" || name == "inherit-product-if-exists" {
+					return ctx.handleVariable(n)
+				}
+			}
 		}
 	}
 
-	return []starlarkNode{ctx.newBadNode(node, "Eval expression too complex; only assignments and comments are supported")}
+	return []starlarkNode{ctx.newBadNode(node, "Eval expression too complex; only assignments, comments, includes, and inherit-products are supported")}
 }
 
 func (ctx *parseContext) parseMakeString(node mkparser.Node, mk *mkparser.MakeString) starlarkExpr {
@@ -1828,7 +1889,7 @@
 				result = []starlarkNode{res}
 			}
 		case "include", "-include":
-			result = ctx.handleInclude(node, ctx.parseMakeString(node, x.Args), x.Name[0] != '-')
+			result = ctx.handleInclude(x)
 		case "ifeq", "ifneq", "ifdef", "ifndef":
 			result = []starlarkNode{ctx.handleIfBlock(x)}
 		default:
diff --git a/mk2rbc/mk2rbc_test.go b/mk2rbc/mk2rbc_test.go
index 9485a42..de2dc3c 100644
--- a/mk2rbc/mk2rbc_test.go
+++ b/mk2rbc/mk2rbc_test.go
@@ -117,8 +117,8 @@
 
 def init(g, handle):
   cfg = rblf.cfg(handle)
-  rblf.mk2rbc_error("product.mk:2", "cannot handle invoking foo1")
-  rblf.mk2rbc_error("product.mk:3", "cannot handle invoking foo0")
+  cfg["PRODUCT_NAME"] = rblf.mk2rbc_error("product.mk:2", "cannot handle invoking foo1")
+  cfg["PRODUCT_NAME"] = rblf.mk2rbc_error("product.mk:3", "cannot handle invoking foo0")
 `,
 	},
 	{
@@ -568,14 +568,18 @@
 endif
 ifneq (,$(wildcard foo*.mk))
 endif
+ifeq (foo1.mk foo2.mk barxyz.mk,$(wildcard foo*.mk bar*.mk))
+endif
 `,
 		expected: `load("//build/make/core:product_config.rbc", "rblf")
 
 def init(g, handle):
   cfg = rblf.cfg(handle)
-  if not rblf.file_exists("foo.mk"):
+  if not rblf.expand_wildcard("foo.mk"):
     pass
-  if rblf.file_wildcard_exists("foo*.mk"):
+  if rblf.expand_wildcard("foo*.mk"):
+    pass
+  if rblf.expand_wildcard("foo*.mk bar*.mk") == ["foo1.mk", "foo2.mk", "barxyz.mk"]:␤
     pass
 `,
 	},
@@ -808,6 +812,10 @@
 PRODUCT_COPY_FILES := $(addprefix pfx-,a b c)
 PRODUCT_COPY_FILES := $(addsuffix .sff, a b c)
 PRODUCT_NAME := $(word 1, $(subst ., ,$(TARGET_BOARD_PLATFORM)))
+ifeq (1,$(words $(SOME_UNKNOWN_VARIABLE)))
+endif
+ifeq ($(words $(SOME_OTHER_VARIABLE)),$(SOME_INT_VARIABLE))
+endif
 $(info $(patsubst %.pub,$(PRODUCT_NAME)%,$(PRODUCT_ADB_KEYS)))
 $(info $$(dir foo/bar): $(dir foo/bar))
 $(info $(firstword $(PRODUCT_COPY_FILES)))
@@ -830,7 +838,11 @@
   cfg = rblf.cfg(handle)
   cfg["PRODUCT_COPY_FILES"] = rblf.addprefix("pfx-", "a b c")
   cfg["PRODUCT_COPY_FILES"] = rblf.addsuffix(".sff", "a b c")
-  cfg["PRODUCT_NAME"] = ((g.get("TARGET_BOARD_PLATFORM", "")).replace(".", " ")).split()[0]
+  cfg["PRODUCT_NAME"] = rblf.words((g.get("TARGET_BOARD_PLATFORM", "")).replace(".", " "))[0]
+  if len(rblf.words(g.get("SOME_UNKNOWN_VARIABLE", ""))) == 1:
+    pass
+  if ("%d" % (len(rblf.words(g.get("SOME_OTHER_VARIABLE", ""))))) == g.get("SOME_INT_VARIABLE", ""):
+    pass
   rblf.mkinfo("product.mk", rblf.mkpatsubst("%.pub", "%s%%" % cfg["PRODUCT_NAME"], g.get("PRODUCT_ADB_KEYS", "")))
   rblf.mkinfo("product.mk", "$(dir foo/bar): %s" % rblf.dir("foo/bar"))
   rblf.mkinfo("product.mk", cfg["PRODUCT_COPY_FILES"][0])
@@ -975,7 +987,7 @@
   rblf.soong_config_namespace(g, "cvd")
   rblf.soong_config_set(g, "cvd", "launch_configs", "cvd_config_auto.json")
   rblf.soong_config_append(g, "cvd", "grub_config", "grub.cfg")
-  rblf.mk2rbc_error("product.mk:7", "SOONG_CONFIG_ variables cannot be referenced, use soong_config_get instead: SOONG_CONFIG_cvd_grub_config")
+  _x = rblf.mk2rbc_error("product.mk:7", "SOONG_CONFIG_ variables cannot be referenced, use soong_config_get instead: SOONG_CONFIG_cvd_grub_config")
 `,
 	}, {
 		desc:   "soong namespace accesses",
@@ -1142,6 +1154,11 @@
 MY_PATH:=foo
 #RBC# include_top vendor/foo1
 $(call inherit-product,$(MY_PATH)/cfg.mk)
+#RBC# include_top vendor/foo1
+$(call inherit-product,$(MY_OTHER_PATH))
+#RBC# include_top vendor/foo1
+$(foreach f,$(MY_MAKEFILES), \
+	$(call inherit-product,$(f)))
 `,
 		expected: `load("//build/make/core:product_config.rbc", "rblf")
 load("//vendor/foo1:cfg.star|init", _cfg_init = "init")
@@ -1156,6 +1173,21 @@
   if not _varmod_init:
     rblf.mkerror("product.mk", "Cannot find %s" % ("%s/cfg.mk" % g["MY_PATH"]))
   rblf.inherit(handle, _varmod, _varmod_init)
+  _entry = {
+    "vendor/foo1/cfg.mk": ("vendor/foo1/cfg", _cfg_init),
+  }.get(g.get("MY_OTHER_PATH", ""))
+  (_varmod, _varmod_init) = _entry if _entry else (None, None)
+  if not _varmod_init:
+    rblf.mkerror("product.mk", "Cannot find %s" % (g.get("MY_OTHER_PATH", "")))
+  rblf.inherit(handle, _varmod, _varmod_init)
+  for f in rblf.words(g.get("MY_MAKEFILES", "")):
+    _entry = {
+      "vendor/foo1/cfg.mk": ("vendor/foo1/cfg", _cfg_init),
+    }.get(f)
+    (_varmod, _varmod_init) = _entry if _entry else (None, None)
+    if not _varmod_init:
+      rblf.mkerror("product.mk", "Cannot find %s" % (f))
+    rblf.inherit(handle, _varmod, _varmod_init)
 `,
 	},
 	{
@@ -1271,6 +1303,7 @@
 		in: `
 ifeq (,$(call foobar))
 endif
+my_sources := $(local-generated-sources-dir)
 `,
 		expected: `load("//build/make/core:product_config.rbc", "rblf")
 
@@ -1278,6 +1311,7 @@
   cfg = rblf.cfg(handle)
   if rblf.mk2rbc_error("build/product.mk:2", "cannot handle invoking foobar"):
     pass
+  _my_sources = rblf.mk2rbc_error("build/product.mk:4", "local-generated-sources-dir is not supported")
 `,
 	},
 	{
@@ -1511,24 +1545,40 @@
 $(eval MY_VAR := foo)
 $(eval # This is a test of eval functions)
 $(eval $(TOO_COMPLICATED) := bar)
+$(eval include foo/font.mk)
+$(eval $(call inherit-product,vendor/foo1/cfg.mk))
+
 $(foreach x,$(MY_LIST_VAR), \
   $(eval PRODUCT_COPY_FILES += foo/bar/$(x):$(TARGET_COPY_OUT_VENDOR)/etc/$(x)) \
-  $(if $(MY_OTHER_VAR),$(eval PRODUCT_COPY_FILES += $(MY_OTHER_VAR):foo/bar/$(x))) \
-)
+  $(if $(MY_OTHER_VAR),$(eval PRODUCT_COPY_FILES += $(MY_OTHER_VAR):foo/bar/$(x))))
 
+$(foreach x,$(MY_LIST_VAR), \
+  $(eval include foo/$(x).mk))
 `,
 		expected: `load("//build/make/core:product_config.rbc", "rblf")
+load("//foo:font.star", _font_init = "init")
+load("//vendor/foo1:cfg.star", _cfg_init = "init")
 
 def init(g, handle):
   cfg = rblf.cfg(handle)
   g["MY_VAR"] = "foo"
   # This is a test of eval functions
-  rblf.mk2rbc_error("product.mk:5", "Eval expression too complex; only assignments and comments are supported")
+  rblf.mk2rbc_error("product.mk:5", "Eval expression too complex; only assignments, comments, includes, and inherit-products are supported")
+  _font_init(g, handle)
+  rblf.inherit(handle, "vendor/foo1/cfg", _cfg_init)
   for x in rblf.words(g.get("MY_LIST_VAR", "")):
     rblf.setdefault(handle, "PRODUCT_COPY_FILES")
     cfg["PRODUCT_COPY_FILES"] += ("foo/bar/%s:%s/etc/%s" % (x, g.get("TARGET_COPY_OUT_VENDOR", ""), x)).split()
     if g.get("MY_OTHER_VAR", ""):
       cfg["PRODUCT_COPY_FILES"] += ("%s:foo/bar/%s" % (g.get("MY_OTHER_VAR", ""), x)).split()
+  for x in rblf.words(g.get("MY_LIST_VAR", "")):
+    _entry = {
+      "foo/font.mk": ("foo/font", _font_init),
+    }.get("foo/%s.mk" % _x)
+    (_varmod, _varmod_init) = _entry if _entry else (None, None)
+    if not _varmod_init:
+      rblf.mkerror("product.mk", "Cannot find %s" % ("foo/%s.mk" % _x))
+    _varmod_init(g, handle)
 `,
 	},
 	{
diff --git a/mk2rbc/node.go b/mk2rbc/node.go
index 7c39b9e..a01abd8 100644
--- a/mk2rbc/node.go
+++ b/mk2rbc/node.go
@@ -83,7 +83,7 @@
 }
 
 type inheritedDynamicModule struct {
-	path             interpolateExpr
+	path             starlarkExpr
 	candidateModules []*moduleInfo
 	loadAlways       bool
 	location         ErrorLocation
@@ -120,7 +120,7 @@
 }
 
 func (i inheritedDynamicModule) pathExpr() starlarkExpr {
-	return &i.path
+	return i.path
 }
 
 func (i inheritedDynamicModule) needsLoadCheck() bool {
diff --git a/multitree/Android.bp b/multitree/Android.bp
new file mode 100644
index 0000000..9b16d20
--- /dev/null
+++ b/multitree/Android.bp
@@ -0,0 +1,19 @@
+package {
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+bootstrap_go_package {
+    name: "soong-multitree",
+    pkgPath: "android/soong/multitree",
+    deps: [
+        "blueprint",
+        "soong-android",
+    ],
+    srcs: [
+        "api_surface.go",
+        "export.go",
+        "metadata.go",
+        "import.go",
+    ],
+    pluginFor: ["soong_build"],
+}
diff --git a/multitree/api_surface.go b/multitree/api_surface.go
new file mode 100644
index 0000000..f739a24
--- /dev/null
+++ b/multitree/api_surface.go
@@ -0,0 +1,119 @@
+// Copyright 2021 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package multitree
+
+import (
+	"android/soong/android"
+	"fmt"
+
+	"github.com/google/blueprint"
+)
+
+var (
+	pctx = android.NewPackageContext("android/soong/multitree")
+)
+
+func init() {
+	RegisterApiSurfaceBuildComponents(android.InitRegistrationContext)
+}
+
+var PrepareForTestWithApiSurface = android.FixtureRegisterWithContext(RegisterApiSurfaceBuildComponents)
+
+func RegisterApiSurfaceBuildComponents(ctx android.RegistrationContext) {
+	ctx.RegisterModuleType("api_surface", ApiSurfaceFactory)
+}
+
+type ApiSurface struct {
+	android.ModuleBase
+	ExportableModuleBase
+	properties apiSurfaceProperties
+
+	allOutputs    android.Paths
+	taggedOutputs map[string]android.Paths
+}
+
+type apiSurfaceProperties struct {
+	Contributions []string
+}
+
+func ApiSurfaceFactory() android.Module {
+	module := &ApiSurface{}
+	module.AddProperties(&module.properties)
+	android.InitAndroidModule(module)
+	InitExportableModule(module)
+	return module
+}
+
+func (surface *ApiSurface) DepsMutator(ctx android.BottomUpMutatorContext) {
+	if surface.properties.Contributions != nil {
+		ctx.AddVariationDependencies(nil, nil, surface.properties.Contributions...)
+	}
+
+}
+func (surface *ApiSurface) GenerateAndroidBuildActions(ctx android.ModuleContext) {
+	contributionFiles := make(map[string]android.Paths)
+	var allOutputs android.Paths
+	ctx.WalkDeps(func(child, parent android.Module) bool {
+		if contribution, ok := child.(ApiContribution); ok {
+			copied := contribution.CopyFilesWithTag(ctx)
+			for tag, files := range copied {
+				contributionFiles[child.Name()+"#"+tag] = files
+			}
+			for _, paths := range copied {
+				allOutputs = append(allOutputs, paths...)
+			}
+			return false // no transitive dependencies
+		}
+		return false
+	})
+
+	// phony target
+	ctx.Build(pctx, android.BuildParams{
+		Rule:   blueprint.Phony,
+		Output: android.PathForPhony(ctx, ctx.ModuleName()),
+		Inputs: allOutputs,
+	})
+
+	surface.allOutputs = allOutputs
+	surface.taggedOutputs = contributionFiles
+}
+
+func (surface *ApiSurface) OutputFiles(tag string) (android.Paths, error) {
+	if tag != "" {
+		return nil, fmt.Errorf("unknown tag: %q", tag)
+	}
+	return surface.allOutputs, nil
+}
+
+func (surface *ApiSurface) TaggedOutputs() map[string]android.Paths {
+	return surface.taggedOutputs
+}
+
+func (surface *ApiSurface) Exportable() bool {
+	return true
+}
+
+var _ android.OutputFileProducer = (*ApiSurface)(nil)
+var _ Exportable = (*ApiSurface)(nil)
+
+type ApiContribution interface {
+	// copy files necessaryt to construct an API surface
+	// For C, it will be map.txt and .h files
+	// For Java, it will be api.txt
+	CopyFilesWithTag(ctx android.ModuleContext) map[string]android.Paths // output paths
+
+	// Generate Android.bp in out/ to use the exported .txt files
+	// GenerateBuildFiles(ctx ModuleContext) Paths //output paths
+}
diff --git a/multitree/export.go b/multitree/export.go
new file mode 100644
index 0000000..aecade5
--- /dev/null
+++ b/multitree/export.go
@@ -0,0 +1,67 @@
+// Copyright 2022 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package multitree
+
+import (
+	"android/soong/android"
+
+	"github.com/google/blueprint/proptools"
+)
+
+type moduleExportProperty struct {
+	// True if the module is exported to the other components in a multi-tree.
+	// Any components in the multi-tree can import this module to use.
+	Export *bool
+}
+
+type ExportableModuleBase struct {
+	properties moduleExportProperty
+}
+
+type Exportable interface {
+	// Properties for the exporable module.
+	exportableModuleProps() *moduleExportProperty
+
+	// Check if this module can be exported.
+	// If this returns false, the module will not be exported regardless of the 'export' value.
+	Exportable() bool
+
+	// Returns 'true' if this module has 'export: true'
+	// This module will not be exported if it returns 'false' to 'Exportable()' interface even if
+	// it has 'export: true'.
+	IsExported() bool
+
+	// Map from tags to outputs.
+	// Each module can tag their outputs for convenience.
+	TaggedOutputs() map[string]android.Paths
+}
+
+type ExportableModule interface {
+	android.Module
+	android.OutputFileProducer
+	Exportable
+}
+
+func InitExportableModule(module ExportableModule) {
+	module.AddProperties(module.exportableModuleProps())
+}
+
+func (m *ExportableModuleBase) exportableModuleProps() *moduleExportProperty {
+	return &m.properties
+}
+
+func (m *ExportableModuleBase) IsExported() bool {
+	return proptools.Bool(m.properties.Export)
+}
diff --git a/multitree/import.go b/multitree/import.go
new file mode 100644
index 0000000..1e5c421
--- /dev/null
+++ b/multitree/import.go
@@ -0,0 +1,96 @@
+// Copyright 2022 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package multitree
+
+import (
+	"android/soong/android"
+)
+
+var (
+	nameSuffix = ".imported"
+)
+
+type MultitreeImportedModuleInterface interface {
+	GetMultitreeImportedModuleName() string
+}
+
+func init() {
+	android.RegisterModuleType("imported_filegroup", importedFileGroupFactory)
+
+	android.PreArchMutators(RegisterMultitreePreArchMutators)
+}
+
+type importedFileGroupProperties struct {
+	// Imported modules from the other components in a multi-tree
+	Imported []string
+}
+
+type importedFileGroup struct {
+	android.ModuleBase
+
+	properties importedFileGroupProperties
+	srcs       android.Paths
+}
+
+func (ifg *importedFileGroup) Name() string {
+	return ifg.BaseModuleName() + nameSuffix
+}
+
+func importedFileGroupFactory() android.Module {
+	module := &importedFileGroup{}
+	module.AddProperties(&module.properties)
+
+	android.InitAndroidModule(module)
+	return module
+}
+
+var _ MultitreeImportedModuleInterface = (*importedFileGroup)(nil)
+
+func (ifg *importedFileGroup) GetMultitreeImportedModuleName() string {
+	// The base module name of the imported filegroup is used as the imported module name
+	return ifg.BaseModuleName()
+}
+
+var _ android.SourceFileProducer = (*importedFileGroup)(nil)
+
+func (ifg *importedFileGroup) Srcs() android.Paths {
+	return ifg.srcs
+}
+
+func (ifg *importedFileGroup) GenerateAndroidBuildActions(ctx android.ModuleContext) {
+	// srcs from this module must not be used. Adding a dot path to avoid the empty
+	// source failure. Still soong returns error when a module wants to build against
+	// this source, which is intended.
+	ifg.srcs = android.PathsForModuleSrc(ctx, []string{"."})
+}
+
+func RegisterMultitreePreArchMutators(ctx android.RegisterMutatorsContext) {
+	ctx.BottomUp("multitree_imported_rename", MultitreeImportedRenameMutator).Parallel()
+}
+
+func MultitreeImportedRenameMutator(ctx android.BottomUpMutatorContext) {
+	if m, ok := ctx.Module().(MultitreeImportedModuleInterface); ok {
+		name := m.GetMultitreeImportedModuleName()
+		if !ctx.OtherModuleExists(name) {
+			// Provide an empty filegroup not to break the build while updating the metadata.
+			// In other cases, soong will report an error to guide users to run 'm update-meta'
+			// first.
+			if !ctx.Config().TargetMultitreeUpdateMeta() {
+				ctx.ModuleErrorf("\"%s\" filegroup must be imported.\nRun 'm update-meta' first to import the filegroup.", name)
+			}
+			ctx.Rename(name)
+		}
+	}
+}
diff --git a/multitree/metadata.go b/multitree/metadata.go
new file mode 100644
index 0000000..3fd7215
--- /dev/null
+++ b/multitree/metadata.go
@@ -0,0 +1,74 @@
+// Copyright 2022 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package multitree
+
+import (
+	"android/soong/android"
+	"encoding/json"
+)
+
+func init() {
+	android.RegisterSingletonType("update-meta", UpdateMetaSingleton)
+}
+
+func UpdateMetaSingleton() android.Singleton {
+	return &updateMetaSingleton{}
+}
+
+type jsonImported struct {
+	FileGroups map[string][]string `json:",omitempty"`
+}
+
+type metadataJsonFlags struct {
+	Imported jsonImported        `json:",omitempty"`
+	Exported map[string][]string `json:",omitempty"`
+}
+
+type updateMetaSingleton struct {
+	importedModules       []string
+	generatedMetadataFile android.OutputPath
+}
+
+func (s *updateMetaSingleton) GenerateBuildActions(ctx android.SingletonContext) {
+	metadata := metadataJsonFlags{
+		Imported: jsonImported{
+			FileGroups: make(map[string][]string),
+		},
+		Exported: make(map[string][]string),
+	}
+	ctx.VisitAllModules(func(module android.Module) {
+		if ifg, ok := module.(*importedFileGroup); ok {
+			metadata.Imported.FileGroups[ifg.BaseModuleName()] = ifg.properties.Imported
+		}
+		if e, ok := module.(ExportableModule); ok {
+			if e.IsExported() && e.Exportable() {
+				for tag, files := range e.TaggedOutputs() {
+					// TODO(b/219846705): refactor this to a dictionary
+					metadata.Exported[e.Name()+":"+tag] = append(metadata.Exported[e.Name()+":"+tag], files.Strings()...)
+				}
+			}
+		}
+	})
+	jsonStr, err := json.Marshal(metadata)
+	if err != nil {
+		ctx.Errorf(err.Error())
+	}
+	s.generatedMetadataFile = android.PathForOutput(ctx, "multitree", "metadata.json")
+	android.WriteFileRule(ctx, s.generatedMetadataFile, string(jsonStr))
+}
+
+func (s *updateMetaSingleton) MakeVars(ctx android.MakeVarsContext) {
+	ctx.Strict("MULTITREE_METADATA", s.generatedMetadataFile.String())
+}
diff --git a/rust/test.go b/rust/test.go
index 250b765..6e53935 100644
--- a/rust/test.go
+++ b/rust/test.go
@@ -15,6 +15,8 @@
 package rust
 
 import (
+	"path/filepath"
+
 	"github.com/google/blueprint/proptools"
 
 	"android/soong/android"
@@ -151,9 +153,15 @@
 			ctx.ModuleErrorf("data_lib %q is not a linkable module", depName)
 		}
 		if linkableDep.OutputFile().Valid() {
+			// Copy the output in "lib[64]" so that it's compatible with
+			// the default rpath values.
+			libDir := "lib"
+			if linkableDep.Target().Arch.ArchType.Multilib == "lib64" {
+				libDir = "lib64"
+			}
 			test.data = append(test.data,
 				android.DataPath{SrcPath: linkableDep.OutputFile().Path(),
-					RelativeInstallPath: linkableDep.RelativeInstallPath()})
+					RelativeInstallPath: filepath.Join(libDir, linkableDep.RelativeInstallPath())})
 		}
 	})
 
diff --git a/rust/test_test.go b/rust/test_test.go
index 1124176..8906f1c 100644
--- a/rust/test_test.go
+++ b/rust/test_test.go
@@ -187,12 +187,12 @@
 		t.Errorf("expected test output file to be 'main_test', but was '%s'", outputPath)
 	}
 	entries := android.AndroidMkEntriesForTest(t, ctx, module)[0]
-	if !strings.HasSuffix(entries.EntryMap["LOCAL_TEST_DATA"][0], ":test_lib.so:foo/bar/baz") {
-		t.Errorf("expected LOCAL_TEST_DATA to end with `:test_lib.so:foo/bar/baz`,"+
+	if !strings.HasSuffix(entries.EntryMap["LOCAL_TEST_DATA"][0], ":test_lib.so:lib64/foo/bar/baz") {
+		t.Errorf("expected LOCAL_TEST_DATA to end with `:test_lib.so:lib64/foo/bar/baz`,"+
 			" but was '%s'", entries.EntryMap["LOCAL_TEST_DATA"][0])
 	}
-	if !strings.HasSuffix(entries.EntryMap["LOCAL_TEST_DATA"][1], ":librust_test_lib.so:foo/bar/baz") {
-		t.Errorf("expected LOCAL_TEST_DATA to end with `:librust_test_lib.so:foo/bar/baz`,"+
+	if !strings.HasSuffix(entries.EntryMap["LOCAL_TEST_DATA"][1], ":librust_test_lib.so:lib64/foo/bar/baz") {
+		t.Errorf("expected LOCAL_TEST_DATA to end with `:librust_test_lib.so:lib64/foo/bar/baz`,"+
 			" but was '%s'", entries.EntryMap["LOCAL_TEST_DATA"][1])
 	}
 	if !strings.HasSuffix(entries.EntryMap["LOCAL_TEST_DATA"][2], ":rusty:foo/bar/baz") {
diff --git a/ui/build/config.go b/ui/build/config.go
index e271bfc..0092ff1 100644
--- a/ui/build/config.go
+++ b/ui/build/config.go
@@ -1223,6 +1223,21 @@
 	return "RBE_use_application_default_credentials", "true"
 }
 
+func (c *configImpl) IsGooglerEnvironment() bool {
+	cf := "ANDROID_BUILD_ENVIRONMENT_CONFIG"
+	if v, ok := c.environ.Get(cf); ok {
+		return v == "googler"
+	}
+	return false
+}
+
+func (c *configImpl) GoogleProdCredsExist() bool {
+	if _, err := exec.Command("/usr/bin/prodcertstatus", "--simple_output", "--nocheck_loas").Output(); err != nil {
+		return false
+	}
+	return true
+}
+
 func (c *configImpl) UseRemoteBuild() bool {
 	return c.UseGoma() || c.UseRBE()
 }
diff --git a/ui/build/rbe.go b/ui/build/rbe.go
index 8f9a699..78d37b4 100644
--- a/ui/build/rbe.go
+++ b/ui/build/rbe.go
@@ -119,6 +119,7 @@
 }
 
 func stopRBE(ctx Context, config Config) {
+	defer checkProdCreds(ctx, config)
 	cmd := Command(ctx, config, "stopRBE bootstrap", rbeCommand(ctx, config, bootstrapCmd), "-shutdown")
 	output, err := cmd.CombinedOutput()
 	if err != nil {
@@ -131,6 +132,15 @@
 	}
 }
 
+func checkProdCreds(ctx Context, config Config) {
+	if !config.IsGooglerEnvironment() || config.GoogleProdCredsExist() {
+		return
+	}
+	fmt.Fprintln(ctx.Writer, "")
+	fmt.Fprintln(ctx.Writer, "\033[33mWARNING: Missing LOAS credentials, please run `gcert`. This will result in failing RBE builds in the future, see go/build-fast#authentication.\033[0m")
+	fmt.Fprintln(ctx.Writer, "")
+}
+
 // DumpRBEMetrics creates a metrics protobuf file containing RBE related metrics.
 // The protobuf file is created if RBE is enabled and the proxy service has
 // started. The proxy service is shutdown in order to dump the RBE metrics to the