diff --git a/android/allowlists/allowlists.go b/android/allowlists/allowlists.go
index 3d64ae3..6014deb 100644
--- a/android/allowlists/allowlists.go
+++ b/android/allowlists/allowlists.go
@@ -503,6 +503,7 @@
 		"prebuilts/clang-tools":/* recursive = */ true,
 		"prebuilts/gcc":/* recursive = */ true,
 		"prebuilts/build-tools":/* recursive = */ true,
+		"prebuilts/jdk/jdk8":/* recursive = */ true,
 		"prebuilts/jdk/jdk17":/* recursive = */ true,
 		"prebuilts/misc":/* recursive = */ false, // not recursive because we need bp2build converted build files in prebuilts/misc/common/asm
 		"prebuilts/sdk":/* recursive = */ false,
@@ -939,6 +940,7 @@
 		"libopenjdkjvmti_headers",
 
 		// tradefed deps
+		"apache-commons-compress",
 		"tradefed-protos",
 		"grpc-java",
 		"grpc-java-api",
@@ -987,6 +989,11 @@
 		"platformprotos",
 		"perfetto_metrics-full",
 		"test-services-normalized.apk",
+		"tradefed-common-util",
+		"tradefed-clearcut-client",
+		"tradefed-result-interfaces",
+		"tradefed-device-build-interfaces",
+		"tradefed-invocation-interfaces",
 	}
 
 	Bp2buildModuleTypeAlwaysConvertList = []string{
diff --git a/android/config.go b/android/config.go
index b3ff86b..f0fc15b 100644
--- a/android/config.go
+++ b/android/config.go
@@ -675,6 +675,7 @@
 		"framework-media":                   {},
 		"framework-mediaprovider":           {},
 		"framework-ondevicepersonalization": {},
+		"framework-pdf":                     {},
 		"framework-permission":              {},
 		"framework-permission-s":            {},
 		"framework-scheduling":              {},
diff --git a/android/filegroup.go b/android/filegroup.go
index 5a8c4b9..b6e37a5 100644
--- a/android/filegroup.go
+++ b/android/filegroup.go
@@ -22,7 +22,6 @@
 	"android/soong/bazel"
 	"android/soong/bazel/cquery"
 	"android/soong/ui/metrics/bp2build_metrics_proto"
-
 	"github.com/google/blueprint"
 	"github.com/google/blueprint/proptools"
 )
@@ -106,8 +105,10 @@
 		if f.Label == fg.Name() {
 			if len(srcs.Value.Includes) > 1 {
 				ctx.ModuleErrorf("filegroup '%s' cannot contain a file with the same name", fg.Name())
+				ctx.MarkBp2buildUnconvertible(bp2build_metrics_proto.UnconvertedReasonType_SRC_NAME_COLLISION, "")
+			} else {
+				panic("This situation should have been handled by FileGroupFactory's call to InitBazelModuleAsHandcrafted")
 			}
-			ctx.MarkBp2buildUnconvertible(bp2build_metrics_proto.UnconvertedReasonType_SRC_NAME_COLLISION, "")
 			return
 		}
 	}
@@ -253,6 +254,16 @@
 	module.AddProperties(&module.properties)
 	InitAndroidModule(module)
 	InitBazelModule(module)
+	AddBazelHandcraftedHook(module, func(ctx LoadHookContext) string {
+		// If there is a single src with the same name as the filegroup module name,
+		// then don't generate this filegroup. It will be OK for other targets
+		// to depend on this source file by name directly.
+		fg := ctx.Module().(*fileGroup)
+		if len(fg.properties.Srcs) == 1 && fg.Name() == fg.properties.Srcs[0] {
+			return fg.Name()
+		}
+		return ""
+	})
 	InitDefaultableModule(module)
 	return module
 }
diff --git a/bazel/aquery.go b/bazel/aquery.go
index 7195a97..641f16b 100644
--- a/bazel/aquery.go
+++ b/bazel/aquery.go
@@ -372,18 +372,20 @@
 		defer eventHandler.End("build_statements")
 		wg := sync.WaitGroup{}
 		var errOnce sync.Once
-
+		id2targets := make(map[uint32]string, len(aqueryProto.Targets))
+		for _, t := range aqueryProto.Targets {
+			id2targets[t.GetId()] = t.GetLabel()
+		}
 		for i, actionEntry := range aqueryProto.Actions {
 			wg.Add(1)
 			go func(i int, actionEntry *analysis_v2_proto.Action) {
-				if buildStatement, aErr := aqueryHandler.actionToBuildStatement(actionEntry); aErr != nil {
+				if strings.HasPrefix(id2targets[actionEntry.TargetId], "@bazel_tools//") {
+					// bazel_tools are removed depsets in `populateDepsetMaps()` so skipping
+					// conversion to build statements as well
+					buildStatements[i] = nil
+				} else if buildStatement, aErr := aqueryHandler.actionToBuildStatement(actionEntry); aErr != nil {
 					errOnce.Do(func() {
-						for _, t := range aqueryProto.Targets {
-							if t.GetId() == actionEntry.GetTargetId() {
-								aErr = fmt.Errorf("%s: [%s] [%s]", aErr.Error(), actionEntry.GetMnemonic(), t.GetLabel())
-								break
-							}
-						}
+						aErr = fmt.Errorf("%s: [%s] [%s]", aErr.Error(), actionEntry.GetMnemonic(), id2targets[actionEntry.TargetId])
 						err = aErr
 					})
 				} else {
diff --git a/bazel/aquery_test.go b/bazel/aquery_test.go
index 32c87a0..cbd2791 100644
--- a/bazel/aquery_test.go
+++ b/bazel/aquery_test.go
@@ -178,8 +178,8 @@
    { "id": 2, "path_fragment_id": 2 }],
  "actions": [{
    "target_id": 1,
-   "action_key": "x",
-   "mnemonic": "x",
+   "action_key": "action_x",
+   "mnemonic": "X",
    "arguments": ["touch", "foo"],
    "input_dep_set_ids": [1],
    "output_ids": [3],
@@ -198,7 +198,7 @@
 		return
 	}
 	_, _, err = AqueryBuildStatements(data, &metrics.EventHandler{})
-	assertError(t, err, "undefined outputId 3")
+	assertError(t, err, "undefined outputId 3: [X] []")
 }
 
 func TestInvalidInputDepsetIdFromAction(t *testing.T) {
@@ -209,13 +209,17 @@
    { "id": 2, "path_fragment_id": 2 }],
  "actions": [{
    "target_id": 1,
-   "action_key": "x",
-   "mnemonic": "x",
+   "action_key": "action_x",
+   "mnemonic": "X",
    "arguments": ["touch", "foo"],
    "input_dep_set_ids": [2],
    "output_ids": [1],
    "primary_output_id": 1
  }],
+ "targets": [{
+   "id": 1,
+   "label": "target_x"
+ }],
  "dep_set_of_files": [
    { "id": 1, "direct_artifact_ids": [1, 2] }],
  "path_fragments": [
@@ -229,7 +233,7 @@
 		return
 	}
 	_, _, err = AqueryBuildStatements(data, &metrics.EventHandler{})
-	assertError(t, err, "undefined (not even empty) input depsetId 2")
+	assertError(t, err, "undefined (not even empty) input depsetId 2: [X] [target_x]")
 }
 
 func TestInvalidInputDepsetIdFromDepset(t *testing.T) {
@@ -383,8 +387,8 @@
    { "id": 4, "path_fragment_id": 4 }],
  "actions": [{
    "target_id": 1,
-   "action_key": "x",
-   "mnemonic": "x",
+   "action_key": "action_x",
+   "mnemonic": "X",
    "arguments": ["touch", "foo"],
    "input_dep_set_ids": [1],
    "output_ids": [2,3,4],
@@ -407,7 +411,7 @@
 		return
 	}
 	_, _, err = AqueryBuildStatements(data, &metrics.EventHandler{})
-	assertError(t, err, `found multiple potential depfiles "two.d", "other.d"`)
+	assertError(t, err, `found multiple potential depfiles "two.d", "other.d": [X] []`)
 }
 
 func TestTransitiveInputDepsets(t *testing.T) {
@@ -559,7 +563,7 @@
 	}, actual)
 }
 
-func TestBazelOutRemovalFromInputDepsets(t *testing.T) {
+func TestBazelToolsRemovalFromInputDepsets(t *testing.T) {
 	const inputString = `{
  "artifacts": [
    { "id": 1, "path_fragment_id": 10 },
@@ -637,7 +641,55 @@
 	}
 }
 
-func TestBazelOutRemovalFromTransitiveInputDepsets(t *testing.T) {
+func TestBazelToolsRemovalFromTargets(t *testing.T) {
+	const inputString = `{
+ "artifacts": [{ "id": 1, "path_fragment_id": 10 }],
+ "targets": [
+   { "id": 100, "label": "targetX" },
+   { "id": 200, "label": "@bazel_tools//tool_y" }
+],
+ "actions": [{
+   "target_id": 100,
+   "action_key": "actionX",
+   "arguments": ["bogus", "command"],
+   "mnemonic" : "x",
+   "output_ids": [1]
+ }, {
+   "target_id": 200,
+   "action_key": "y"
+ }],
+ "path_fragments": [{ "id": 10, "label": "outputX"}]
+}`
+	data, err := JsonToActionGraphContainer(inputString)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	actualBuildStatements, actualDepsets, _ := AqueryBuildStatements(data, &metrics.EventHandler{})
+	if len(actualDepsets) != 0 {
+		t.Errorf("expected 0 depset but found %#v", actualDepsets)
+		return
+	}
+	expectedBuildStatement := &BuildStatement{
+		Command:      "bogus command",
+		OutputPaths:  []string{"outputX"},
+		Mnemonic:     "x",
+		SymlinkPaths: []string{},
+	}
+	buildStatementFound := false
+	for _, actualBuildStatement := range actualBuildStatements {
+		if buildStatementEquals(actualBuildStatement, expectedBuildStatement) == "" {
+			buildStatementFound = true
+			break
+		}
+	}
+	if !buildStatementFound {
+		t.Errorf("expected but missing %#v in %#v build statements", expectedBuildStatement, len(actualBuildStatements))
+		return
+	}
+}
+
+func TestBazelToolsRemovalFromTransitiveInputDepsets(t *testing.T) {
 	const inputString = `{
  "artifacts": [
    { "id": 1, "path_fragment_id": 10 },
@@ -939,7 +991,7 @@
    { "id": 3, "path_fragment_id": 3 }],
  "actions": [{
    "target_id": 1,
-   "action_key": "x",
+   "action_key": "action_x",
    "mnemonic": "Symlink",
    "input_dep_set_ids": [1],
    "output_ids": [3],
@@ -958,7 +1010,7 @@
 		return
 	}
 	_, _, err = AqueryBuildStatements(data, &metrics.EventHandler{})
-	assertError(t, err, `Expect 1 input and 1 output to symlink action, got: input ["file" "other_file"], output ["symlink"]`)
+	assertError(t, err, `Expect 1 input and 1 output to symlink action, got: input ["file" "other_file"], output ["symlink"]: [Symlink] []`)
 }
 
 func TestSymlinkMultipleOutputs(t *testing.T) {
@@ -989,7 +1041,7 @@
 		return
 	}
 	_, _, err = AqueryBuildStatements(data, &metrics.EventHandler{})
-	assertError(t, err, "undefined outputId 2")
+	assertError(t, err, "undefined outputId 2: [Symlink] []")
 }
 
 func TestTemplateExpandActionSubstitutions(t *testing.T) {
@@ -1066,7 +1118,7 @@
 		return
 	}
 	_, _, err = AqueryBuildStatements(data, &metrics.EventHandler{})
-	assertError(t, err, `Expect 1 output to template expand action, got: output []`)
+	assertError(t, err, `Expect 1 output to template expand action, got: output []: [TemplateExpand] []`)
 }
 
 func TestFileWrite(t *testing.T) {
diff --git a/bp2build/filegroup_conversion_test.go b/bp2build/filegroup_conversion_test.go
index cb2e207..9c49dac 100644
--- a/bp2build/filegroup_conversion_test.go
+++ b/bp2build/filegroup_conversion_test.go
@@ -40,7 +40,9 @@
     srcs: ["foo"],
 }
 `,
-		ExpectedBazelTargets: []string{}})
+		ExpectedBazelTargets:       []string{},
+		ExpectedHandcraftedModules: []string{"foo"}},
+	)
 }
 
 func TestFilegroupSameNameAsFile_MultipleFiles(t *testing.T) {
diff --git a/bp2build/symlink_forest.go b/bp2build/symlink_forest.go
index 966b94a..06e63ca 100644
--- a/bp2build/symlink_forest.go
+++ b/bp2build/symlink_forest.go
@@ -22,7 +22,6 @@
 	"regexp"
 	"sort"
 	"strconv"
-	"strings"
 	"sync"
 	"sync/atomic"
 
@@ -32,19 +31,12 @@
 )
 
 // A tree structure that describes what to do at each directory in the created
-// symlink tree. Currently it is used to enumerate which files/directories
+// symlink tree. Currently, it is used to enumerate which files/directories
 // should be excluded from symlinking. Each instance of "node" represents a file
 // or a directory. If excluded is true, then that file/directory should be
 // excluded from symlinking. Otherwise, the node is not excluded, but one of its
 // descendants is (otherwise the node in question would not exist)
 
-// This is a version int written to a file called symlink_forest_version at the root of the
-// symlink forest. If the version here does not match the version in the file, then we'll
-// clean the whole symlink forest and recreate it. This number can be bumped whenever there's
-// an incompatible change to the forest layout or a bug in incrementality that needs to be fixed
-// on machines that may still have the bug present in their forest.
-const symlinkForestVersion = 2
-
 type instructionsNode struct {
 	name     string
 	excluded bool // If false, this is just an intermediate node
@@ -193,7 +185,7 @@
 	srcPath := shared.JoinPath(topdir, src)
 	dstPath := shared.JoinPath(topdir, dst)
 
-	// Check if a symlink already exists.
+	// Check whether a symlink already exists.
 	if dstInfo, err := os.Lstat(dstPath); err != nil {
 		if !os.IsNotExist(err) {
 			fmt.Fprintf(os.Stderr, "Failed to lstat '%s': %s", dst, err)
@@ -240,44 +232,49 @@
 	return false
 }
 
-// maybeCleanSymlinkForest will remove the whole symlink forest directory if the version recorded
-// in the symlink_forest_version file is not equal to symlinkForestVersion.
-func maybeCleanSymlinkForest(topdir, forest string, verbose bool) error {
-	versionFilePath := shared.JoinPath(topdir, forest, "symlink_forest_version")
-	versionFileContents, err := os.ReadFile(versionFilePath)
+// Returns the hash of the soong_build binary to determine whether we should
+// force symlink_forest to re-execute
+// This is similar to a version number increment - but that shouldn't be required
+// for every update to this file
+func getSoongBuildMTime() int64 {
+	binaryPath, err := os.Executable()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error finding executable path %s\n", err)
+		os.Exit(1)
+	}
+
+	info, err := os.Stat(binaryPath)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error stating executable path %s\n", err)
+	}
+
+	return info.ModTime().UnixMilli()
+}
+
+// maybeCleanSymlinkForest will remove the whole symlink forest directory  if the soong_build
+// binary has changed since the last execution.
+func maybeCleanSymlinkForest(topdir, forest string, verbose bool, soongBuildMTime int64) error {
+	mtimeFilePath := shared.JoinPath(topdir, forest, "soong_build_mtime")
+	mtimeFileContents, err := os.ReadFile(mtimeFilePath)
 	if err != nil && !os.IsNotExist(err) {
 		return err
 	}
-	versionFileString := strings.TrimSpace(string(versionFileContents))
-	symlinkForestVersionString := strconv.Itoa(symlinkForestVersion)
-	if err != nil || versionFileString != symlinkForestVersionString {
-		if verbose {
-			fmt.Fprintf(os.Stderr, "Old symlink_forest_version was %q, current is %q. Cleaning symlink forest before recreating...\n", versionFileString, symlinkForestVersionString)
-		}
+
+	if string(soongBuildMTime) != string(mtimeFileContents) {
 		err = os.RemoveAll(shared.JoinPath(topdir, forest))
 		if err != nil {
 			return err
 		}
 	}
+
 	return nil
 }
 
-// maybeWriteVersionFile will write the symlink_forest_version file containing symlinkForestVersion
-// if it doesn't exist already. If it exists we know it must contain symlinkForestVersion because
-// we checked for that already in maybeCleanSymlinkForest
-func maybeWriteVersionFile(topdir, forest string) error {
-	versionFilePath := shared.JoinPath(topdir, forest, "symlink_forest_version")
-	_, err := os.Stat(versionFilePath)
-	if err != nil {
-		if !os.IsNotExist(err) {
-			return err
-		}
-		err = os.WriteFile(versionFilePath, []byte(strconv.Itoa(symlinkForestVersion)+"\n"), 0666)
-		if err != nil {
-			return err
-		}
-	}
-	return nil
+func writeSoongBuildMTimeFile(topdir, forest string, mtime int64) error {
+	hashFilePath := shared.JoinPath(topdir, forest, "soong_build_mtime")
+	contents := []byte(strconv.FormatInt(mtime, 10))
+
+	return os.WriteFile(hashFilePath, contents, 0666)
 }
 
 // Recursively plants a symlink forest at forestDir. The symlink tree will
@@ -473,7 +470,10 @@
 		symlinkCount: atomic.Uint64{},
 	}
 
-	err := maybeCleanSymlinkForest(topdir, forest, verbose)
+	// Check whether soong_build has been modified since the last run
+	soongBuildMTime := getSoongBuildMTime()
+
+	err := maybeCleanSymlinkForest(topdir, forest, verbose, soongBuildMTime)
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)
@@ -491,11 +491,10 @@
 		deps = append(deps, dep)
 	}
 
-	err = maybeWriteVersionFile(topdir, forest)
+	err = writeSoongBuildMTimeFile(topdir, forest, soongBuildMTime)
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)
 	}
-
 	return deps, context.mkdirCount.Load(), context.symlinkCount.Load()
 }
diff --git a/cc/config/global.go b/cc/config/global.go
index a586a3f..62b008b 100644
--- a/cc/config/global.go
+++ b/cc/config/global.go
@@ -29,83 +29,112 @@
 	// Flags used by lots of devices.  Putting them in package static variables
 	// will save bytes in build.ninja so they aren't repeated for every file
 	commonGlobalCflags = []string{
-		"-DANDROID",
-		"-fmessage-length=0",
-		"-W",
+		// Enable some optimization by default.
+		"-O2",
+
+		// Warnings enabled by default. Reference:
+		// https://clang.llvm.org/docs/DiagnosticsReference.html
 		"-Wall",
-		"-Wno-unused",
+		"-Wextra",
 		"-Winit-self",
 		"-Wpointer-arith",
-		"-Wunreachable-code-loop-increment",
+		"-Wunguarded-availability",
 
-		// Make paths in deps files relative
-		"-no-canonical-prefixes",
+		// Warnings treated as errors by default.
+		// See also noOverrideGlobalCflags for errors that cannot be disabled
+		// from Android.bp files.
 
-		"-DNDEBUG",
-		"-UDEBUG",
-
-		"-fno-exceptions",
-
-		"-O2",
-		"-fdebug-default-version=5",
-
-		"-fno-strict-aliasing",
-
+		// Using __DATE__/__TIME__ causes build nondeterminism.
 		"-Werror=date-time",
+		// Detects forgotten */& that usually cause a crash
+		"-Werror=int-conversion",
+		// Detects unterminated alignment modification pragmas, which often lead
+		// to ABI mismatch between modules and hard-to-debug crashes.
 		"-Werror=pragma-pack",
+		// Same as above, but detects alignment pragmas around a header
+		// inclusion.
 		"-Werror=pragma-pack-suspicious-include",
+		// Detects dividing an array size by itself, which is a common typo that
+		// leads to bugs.
+		"-Werror=sizeof-array-div",
+		// Detects a typo that cuts off a prefix from a string literal.
 		"-Werror=string-plus-int",
+		// Detects for loops that will never execute more than once (for example
+		// due to unconditional break), but have a non-empty loop increment
+		// clause. Often a mistake/bug.
 		"-Werror=unreachable-code-loop-increment",
 
-		// Force deprecation warnings to be warnings for code that compiles with -Werror.
-		// Making deprecated usages an error causes extreme pain when trying to deprecate anything.
-		"-Wno-error=deprecated-declarations",
+		// Warnings that should not be errors even for modules with -Werror.
 
+		// Making deprecated usages an error causes extreme pain when trying to
+		// deprecate anything.
+		"-Wno-error=deprecated-declarations",
+		// This rarely indicates a bug. http://b/145210666
+		"-Wno-error=reorder-init-list",
+
+		// Warnings disabled by default.
+
+		// Designated initializer syntax is recommended by the Google C++ style
+		// and is OK to use even if not formally supported by the chosen C++
+		// version.
+		"-Wno-c99-designator",
+		// Detects uses of a GNU C extension equivalent to a limited form of
+		// constexpr. Enabling this would require replacing many constants with
+		// macros, which is not a good trade-off.
+		"-Wno-gnu-folding-constant",
+		// AIDL generated code redeclares pure virtual methods in each
+		// subsequent version of an interface, so this warning is currently
+		// infeasible to enable.
+		"-Wno-inconsistent-missing-override",
+		// Incompatible with the Google C++ style guidance to use 'int' for loop
+		// indices; poor signal to noise ratio.
+		"-Wno-sign-compare",
+		// Poor signal to noise ratio.
+		"-Wno-unused",
+
+		// Global preprocessor constants.
+
+		"-DANDROID",
+		"-DNDEBUG",
+		"-UDEBUG",
 		"-D__compiler_offsetof=__builtin_offsetof",
+		// Allows the bionic versioning.h to indirectly determine whether the
+		// option -Wunguarded-availability is on or not.
+		"-D__ANDROID_UNAVAILABLE_SYMBOLS_ARE_WEAK__",
+
+		// -f and -g options.
 
 		// Emit address-significance table which allows linker to perform safe ICF. Clang does
 		// not emit the table by default on Android since NDK still uses GNU binutils.
 		"-faddrsig",
 
-		// Help catch common 32/64-bit errors.
-		"-Werror=int-conversion",
+		// Emit debugging data in a modern format (DWARF v5).
+		"-fdebug-default-version=5",
 
 		// Force clang to always output color diagnostics. Ninja will strip the ANSI
 		// color codes if it is not running in a terminal.
 		"-fcolor-diagnostics",
 
-		// -Wno-sign-compare is incompatible with the Google C++ style guidance
-		// to use 'int' for loop indices, and the signal to noise ratio is poor
-		// anyway.
-		"-Wno-sign-compare",
-
-		// AIDL generated code redeclares pure virtual methods in each
-		// subsequent version of an interface, so this is currently infeasible
-		// to enable.
-		"-Wno-inconsistent-missing-override",
-
-		// Designated initializer syntax is recommended by the Google C++ style
-		// guide and should not be a warning, at least by default.
-		"-Wno-c99-designator",
-
-		// Warnings from clang-12
-		"-Wno-gnu-folding-constant",
-
-		// http://b/145210666
-		"-Wno-error=reorder-init-list",
-
-		// Calls to the APIs that are newer than the min sdk version of the caller should be
-		// guarded with __builtin_available.
-		"-Wunguarded-availability",
-		// This macro allows the bionic versioning.h to indirectly determine whether the
-		// option -Wunguarded-availability is on or not.
-		"-D__ANDROID_UNAVAILABLE_SYMBOLS_ARE_WEAK__",
-
 		// Turn off FMA which got enabled by default in clang-r445002 (http://b/218805949)
 		"-ffp-contract=off",
 
+		// Google C++ style does not allow exceptions, turn them off by default.
+		"-fno-exceptions",
+
+		// Disable optimizations based on strict aliasing by default.
+		// The performance benefit of enabling them currently does not outweigh
+		// the risk of hard-to-reproduce bugs.
+		"-fno-strict-aliasing",
+
+		// Disable line wrapping for error messages - it interferes with
+		// displaying logs in web browsers.
+		"-fmessage-length=0",
+
 		// Using simple template names reduces the size of debug builds.
 		"-gsimple-template-names",
+
+		// Make paths in deps files relative.
+		"-no-canonical-prefixes",
 	}
 
 	commonGlobalConlyflags = []string{}
@@ -117,6 +146,7 @@
 		"-fdebug-default-version=4",
 	}
 
+	// Compilation flags for device code; not applied to host code.
 	deviceGlobalCflags = []string{
 		"-ffunction-sections",
 		"-fdata-sections",
@@ -152,6 +182,7 @@
 		"-fvisibility-inlines-hidden",
 	}
 
+	// Linking flags for device code; not applied to host binaries.
 	deviceGlobalLdflags = []string{
 		"-Wl,-z,noexecstack",
 		"-Wl,-z,relro",
@@ -180,8 +211,6 @@
 	hostGlobalLldflags = commonGlobalLldflags
 
 	commonGlobalCppflags = []string{
-		"-Wsign-promo",
-
 		// -Wimplicit-fallthrough is not enabled by -Wall.
 		"-Wimplicit-fallthrough",
 
@@ -194,6 +223,14 @@
 
 	// These flags are appended after the module's cflags, so they cannot be
 	// overridden from Android.bp files.
+	//
+	// NOTE: if you need to disable a warning to unblock a compiler upgrade
+	// and it is only triggered by third party code, add it to
+	// extraExternalCflags (if possible) or noOverrideExternalGlobalCflags
+	// (if the former doesn't work). If the new warning also occurs in first
+	// party code, try adding it to commonGlobalCflags first. Adding it here
+	// should be the last resort, because it prevents all code in Android from
+	// opting into the warning.
 	noOverrideGlobalCflags = []string{
 		"-Werror=bool-operation",
 		"-Werror=format-insufficient-args",
@@ -245,35 +282,9 @@
 
 	noOverride64GlobalCflags = []string{}
 
-	// Similar to noOverrideGlobalCflags, but applies only to third-party code
-	// (anything for which IsThirdPartyPath() in build/soong/android/paths.go
-	// returns true - includes external/, most of vendor/ and most of hardware/)
-	noOverrideExternalGlobalCflags = []string{
-		// http://b/151457797
-		"-fcommon",
-		// http://b/191699019
-		"-Wno-format-insufficient-args",
-		// http://b/296321145
-		// Indicates potential memory or stack corruption, so should be changed
-		// to a hard error. Currently triggered by some vendor code.
-		"-Wno-incompatible-function-pointer-types",
-		// http://b/296321508
-		// Introduced in response to a critical security vulnerability and
-		// should be a hard error - it requires only whitespace changes to fix.
-		"-Wno-misleading-indentation",
-		// Triggered by old LLVM code in external/llvm. Likely not worth
-		// enabling since it's a cosmetic issue.
-		"-Wno-bitwise-instead-of-logical",
-
-		"-Wno-unused-but-set-variable",
-		"-Wno-unused-but-set-parameter",
-		"-Wno-unqualified-std-cast-call",
-		"-Wno-array-parameter",
-		"-Wno-gnu-offsetof-extensions",
-	}
-
-	// Extra cflags for external third-party projects to disable warnings that
-	// are infeasible to fix in all the external projects and their upstream repos.
+	// Extra cflags applied to third-party code (anything for which
+	// IsThirdPartyPath() in build/soong/android/paths.go returns true;
+	// includes external/, most of vendor/ and most of hardware/)
 	extraExternalCflags = []string{
 		"-Wno-enum-compare",
 		"-Wno-enum-compare-switch",
@@ -303,11 +314,41 @@
 		"-Wno-deprecated-non-prototype",
 	}
 
+	// Similar to noOverrideGlobalCflags, but applies only to third-party code
+	// (see extraExternalCflags).
+	// This section can unblock compiler upgrades when a third party module that
+	// enables -Werror and some group of warnings explicitly triggers newly
+	// added warnings.
+	noOverrideExternalGlobalCflags = []string{
+		// http://b/151457797
+		"-fcommon",
+		// http://b/191699019
+		"-Wno-format-insufficient-args",
+		// http://b/296321145
+		// Indicates potential memory or stack corruption, so should be changed
+		// to a hard error. Currently triggered by some vendor code.
+		"-Wno-incompatible-function-pointer-types",
+		// http://b/296321508
+		// Introduced in response to a critical security vulnerability and
+		// should be a hard error - it requires only whitespace changes to fix.
+		"-Wno-misleading-indentation",
+		// Triggered by old LLVM code in external/llvm. Likely not worth
+		// enabling since it's a cosmetic issue.
+		"-Wno-bitwise-instead-of-logical",
+
+		"-Wno-unused-but-set-variable",
+		"-Wno-unused-but-set-parameter",
+		"-Wno-unqualified-std-cast-call",
+		"-Wno-array-parameter",
+		"-Wno-gnu-offsetof-extensions",
+	}
+
 	llvmNextExtraCommonGlobalCflags = []string{
 		// Do not report warnings when testing with the top of trunk LLVM.
 		"-Wno-error",
 	}
 
+	// Flags that must not appear in any command line.
 	IllegalFlags = []string{
 		"-w",
 	}
diff --git a/cc/fdo_profile.go b/cc/fdo_profile.go
index 05a8f46..cd3eb1e 100644
--- a/cc/fdo_profile.go
+++ b/cc/fdo_profile.go
@@ -72,7 +72,8 @@
 
 	ctx.CreateBazelTargetModuleWithRestrictions(
 		bazel.BazelTargetModuleProperties{
-			Rule_class: "fdo_profile",
+			Bzl_load_location: "//build/bazel/rules/fdo:fdo_profile.bzl",
+			Rule_class:        "fdo_profile",
 		},
 		android.CommonAttributes{
 			Name: fp.Name(),
diff --git a/java/base.go b/java/base.go
index 53414d9..c685fba 100644
--- a/java/base.go
+++ b/java/base.go
@@ -641,6 +641,11 @@
 		return nil, fmt.Errorf("%q was requested, but no output file was found.", tag)
 	case ".generated_srcjars":
 		return j.properties.Generated_srcjars, nil
+	case ".lint":
+		if j.linter.outputs.xml != nil {
+			return android.Paths{j.linter.outputs.xml}, nil
+		}
+		return nil, fmt.Errorf("%q was requested, but no output file was found.", tag)
 	default:
 		return nil, fmt.Errorf("unsupported module reference tag %q", tag)
 	}
diff --git a/java/dex.go b/java/dex.go
index c1d51c7..3468a70 100644
--- a/java/dex.go
+++ b/java/dex.go
@@ -110,7 +110,8 @@
 			`${config.Zip2ZipCmd} -i $in -o $tmpJar -x '**/*.dex' && ` +
 			`$d8Template${config.D8Cmd} ${config.D8Flags} --output $outDir $d8Flags $tmpJar && ` +
 			`$zipTemplate${config.SoongZipCmd} $zipFlags -o $outDir/classes.dex.jar -C $outDir -f "$outDir/classes*.dex" && ` +
-			`${config.MergeZipsCmd} -D -stripFile "**/*.class" $mergeZipsFlags $out $outDir/classes.dex.jar $in`,
+			`${config.MergeZipsCmd} -D -stripFile "**/*.class" $mergeZipsFlags $out $outDir/classes.dex.jar $in && ` +
+			`rm -f "$tmpJar" "$outDir/classes*.dex" "$outDir/classes.dex.jar"`,
 		CommandDeps: []string{
 			"${config.D8Cmd}",
 			"${config.Zip2ZipCmd}",
@@ -152,7 +153,8 @@
 			`${config.SoongZipCmd} -o ${outUsageZip} -C ${outUsageDir} -f ${outUsage} && ` +
 			`rm -rf ${outUsageDir} && ` +
 			`$zipTemplate${config.SoongZipCmd} $zipFlags -o $outDir/classes.dex.jar -C $outDir -f "$outDir/classes*.dex" && ` +
-			`${config.MergeZipsCmd} -D -stripFile "**/*.class" $mergeZipsFlags $out $outDir/classes.dex.jar $in`,
+			`${config.MergeZipsCmd} -D -stripFile "**/*.class" $mergeZipsFlags $out $outDir/classes.dex.jar $in && ` +
+			`rm -f "$tmpJar" "$outDir/classes*.dex" "$outDir/classes.dex.jar"`,
 		Depfile: "${out}.d",
 		Deps:    blueprint.DepsGCC,
 		CommandDeps: []string{
diff --git a/java/lint.go b/java/lint.go
index f84f1c0..34720e5 100644
--- a/java/lint.go
+++ b/java/lint.go
@@ -66,6 +66,10 @@
 		// This will be true by default for test module types, false otherwise.
 		// If soong gets support for testonly, this flag should be replaced with that.
 		Test *bool
+
+		// Whether to ignore the exit code of Android lint. This is the --exit_code
+		// option. Defaults to false.
+		Suppress_exit_code *bool
 	}
 }
 
@@ -504,7 +508,8 @@
 	rule.Temporary(lintPaths.projectXML)
 	rule.Temporary(lintPaths.configXML)
 
-	if exitCode := ctx.Config().Getenv("ANDROID_LINT_SUPPRESS_EXIT_CODE"); exitCode == "" {
+	suppressExitCode := BoolDefault(l.properties.Lint.Suppress_exit_code, false)
+	if exitCode := ctx.Config().Getenv("ANDROID_LINT_SUPPRESS_EXIT_CODE"); exitCode == "" && !suppressExitCode {
 		cmd.Flag("--exitcode")
 	}
 
diff --git a/rust/builder.go b/rust/builder.go
index b1f049d..9614d4f 100644
--- a/rust/builder.go
+++ b/rust/builder.go
@@ -373,17 +373,24 @@
 	}
 
 	rustcOutputFile := outputFile
+	var rustcImplicitOutputs android.WritablePaths
 	usesLinker := crateType == "bin" || crateType == "dylib" || crateType == "cdylib" || crateType == "proc-macro"
 	if usesLinker {
 		rustcOutputFile = android.PathForModuleOut(ctx, outputFile.Base()+".rsp")
+		rustcImplicitOutputs = android.WritablePaths{
+			android.PathForModuleOut(ctx, rustcOutputFile.Base()+".whole.a"),
+			android.PathForModuleOut(ctx, rustcOutputFile.Base()+".a"),
+		}
+
 	}
 
 	ctx.Build(pctx, android.BuildParams{
-		Rule:        rustc,
-		Description: "rustc " + main.Rel(),
-		Output:      rustcOutputFile,
-		Inputs:      inputs,
-		Implicits:   implicits,
+		Rule:            rustc,
+		Description:     "rustc " + main.Rel(),
+		Output:          rustcOutputFile,
+		Inputs:          inputs,
+		Implicits:       implicits,
+		ImplicitOutputs: rustcImplicitOutputs,
 		Args: map[string]string{
 			"rustcFlags": strings.Join(rustcFlags, " "),
 			"libFlags":   strings.Join(libFlags, " "),
diff --git a/rust/builder_test.go b/rust/builder_test.go
index 5c11cb7..1fd675f 100644
--- a/rust/builder_test.go
+++ b/rust/builder_test.go
@@ -14,7 +14,11 @@
 
 package rust
 
-import "testing"
+import (
+	"android/soong/android"
+	"sort"
+	"testing"
+)
 
 func TestSourceProviderCollision(t *testing.T) {
 	testRustError(t, "multiple source providers generate the same filename output: bindings.rs", `
@@ -40,3 +44,122 @@
 		}
 	`)
 }
+
+func TestCompilationOutputFiles(t *testing.T) {
+	ctx := testRust(t, `
+		rust_library {
+			name: "libfizz_buzz",
+			crate_name:"fizz_buzz",
+			srcs: ["lib.rs"],
+		}
+		rust_binary {
+			name: "fizz_buzz",
+			crate_name:"fizz_buzz",
+			srcs: ["lib.rs"],
+		}
+		rust_ffi {
+			name: "librust_ffi",
+			crate_name: "rust_ffi",
+			srcs: ["lib.rs"],
+		}
+	`)
+	testcases := []struct {
+		testName      string
+		moduleName    string
+		variant       string
+		expectedFiles []string
+	}{
+		{
+			testName:   "dylib",
+			moduleName: "libfizz_buzz",
+			variant:    "android_arm64_armv8-a_dylib",
+			expectedFiles: []string{
+				"out/soong/.intermediates/libfizz_buzz/android_arm64_armv8-a_dylib/libfizz_buzz.dylib.so",
+				"out/soong/.intermediates/libfizz_buzz/android_arm64_armv8-a_dylib/libfizz_buzz.dylib.so.clippy",
+				"out/soong/.intermediates/libfizz_buzz/android_arm64_armv8-a_dylib/libfizz_buzz.dylib.so.rsp",
+				"out/soong/.intermediates/libfizz_buzz/android_arm64_armv8-a_dylib/libfizz_buzz.dylib.so.rsp.a",
+				"out/soong/.intermediates/libfizz_buzz/android_arm64_armv8-a_dylib/libfizz_buzz.dylib.so.rsp.whole.a",
+				"out/soong/.intermediates/libfizz_buzz/android_arm64_armv8-a_dylib/unstripped/libfizz_buzz.dylib.so",
+				"out/soong/target/product/test_device/system/lib64/libfizz_buzz.dylib.so",
+				"out/soong/.intermediates/libfizz_buzz/android_arm64_armv8-a_dylib/meta_lic",
+			},
+		},
+		{
+			testName:   "rlib dylib-std",
+			moduleName: "libfizz_buzz",
+			variant:    "android_arm64_armv8-a_rlib_dylib-std",
+			expectedFiles: []string{
+				"out/soong/.intermediates/libfizz_buzz/android_arm64_armv8-a_rlib_dylib-std/libfizz_buzz.rlib",
+				"out/soong/.intermediates/libfizz_buzz/android_arm64_armv8-a_rlib_dylib-std/libfizz_buzz.rlib.clippy",
+				"out/soong/.intermediates/libfizz_buzz/android_arm64_armv8-a_rlib_dylib-std/meta_lic",
+			},
+		},
+		{
+			testName:   "rlib rlib-std",
+			moduleName: "libfizz_buzz",
+			variant:    "android_arm64_armv8-a_rlib_rlib-std",
+			expectedFiles: []string{
+				"out/soong/.intermediates/libfizz_buzz/android_arm64_armv8-a_rlib_rlib-std/libfizz_buzz.rlib",
+				"out/soong/.intermediates/libfizz_buzz/android_arm64_armv8-a_rlib_rlib-std/libfizz_buzz.rlib.clippy",
+				"out/soong/.intermediates/libfizz_buzz/android_arm64_armv8-a_rlib_rlib-std/meta_lic",
+				"out/soong/.intermediates/libfizz_buzz/android_arm64_armv8-a_rlib_rlib-std/rustdoc.timestamp",
+			},
+		},
+		{
+			testName:   "rust_binary",
+			moduleName: "fizz_buzz",
+			variant:    "android_arm64_armv8-a",
+			expectedFiles: []string{
+				"out/soong/.intermediates/fizz_buzz/android_arm64_armv8-a/fizz_buzz",
+				"out/soong/.intermediates/fizz_buzz/android_arm64_armv8-a/fizz_buzz.clippy",
+				"out/soong/.intermediates/fizz_buzz/android_arm64_armv8-a/fizz_buzz.rsp",
+				"out/soong/.intermediates/fizz_buzz/android_arm64_armv8-a/fizz_buzz.rsp.a",
+				"out/soong/.intermediates/fizz_buzz/android_arm64_armv8-a/fizz_buzz.rsp.whole.a",
+				"out/soong/.intermediates/fizz_buzz/android_arm64_armv8-a/unstripped/fizz_buzz",
+				"out/soong/target/product/test_device/system/bin/fizz_buzz",
+				"out/soong/.intermediates/fizz_buzz/android_arm64_armv8-a/meta_lic",
+			},
+		},
+		{
+			testName:   "rust_ffi static",
+			moduleName: "librust_ffi",
+			variant:    "android_arm64_armv8-a_static",
+			expectedFiles: []string{
+				"out/soong/.intermediates/librust_ffi/android_arm64_armv8-a_static/librust_ffi.a",
+				"out/soong/.intermediates/librust_ffi/android_arm64_armv8-a_static/librust_ffi.a.clippy",
+				"out/soong/.intermediates/librust_ffi/android_arm64_armv8-a_static/meta_lic",
+				"out/soong/.intermediates/librust_ffi/android_arm64_armv8-a_static/rustdoc.timestamp",
+			},
+		},
+		{
+			testName:   "rust_ffi shared",
+			moduleName: "librust_ffi",
+			variant:    "android_arm64_armv8-a_shared",
+			expectedFiles: []string{
+				"out/soong/.intermediates/librust_ffi/android_arm64_armv8-a_shared/librust_ffi.so",
+				"out/soong/.intermediates/librust_ffi/android_arm64_armv8-a_shared/librust_ffi.so.clippy",
+				"out/soong/.intermediates/librust_ffi/android_arm64_armv8-a_shared/librust_ffi.so.rsp",
+				"out/soong/.intermediates/librust_ffi/android_arm64_armv8-a_shared/librust_ffi.so.rsp.a",
+				"out/soong/.intermediates/librust_ffi/android_arm64_armv8-a_shared/librust_ffi.so.rsp.whole.a",
+				"out/soong/.intermediates/librust_ffi/android_arm64_armv8-a_shared/unstripped/librust_ffi.so",
+				"out/soong/.intermediates/librust_ffi/android_arm64_armv8-a_shared/unstripped/librust_ffi.so.toc",
+				"out/soong/.intermediates/librust_ffi/android_arm64_armv8-a_shared/meta_lic",
+				"out/soong/target/product/test_device/system/lib64/librust_ffi.so",
+			},
+		},
+	}
+	for _, tc := range testcases {
+		t.Run(tc.testName, func(t *testing.T) {
+			modOutputs := ctx.ModuleForTests(tc.moduleName, tc.variant).AllOutputs()
+			sort.Strings(tc.expectedFiles)
+			sort.Strings(modOutputs)
+			android.AssertStringPathsRelativeToTopEquals(
+				t,
+				"incorrect outputs from rust module",
+				ctx.Config(),
+				tc.expectedFiles,
+				modOutputs,
+			)
+		})
+	}
+}
diff --git a/tests/run_integration_tests.sh b/tests/run_integration_tests.sh
index 6b9ff8b..2349993 100755
--- a/tests/run_integration_tests.sh
+++ b/tests/run_integration_tests.sh
@@ -10,6 +10,7 @@
 "$TOP/build/soong/tests/persistent_bazel_test.sh"
 "$TOP/build/soong/tests/soong_test.sh"
 "$TOP/build/soong/tests/stale_metrics_files_test.sh"
+"$TOP/build/soong/tests/symlink_forest_rerun_test.sh"
 "$TOP/prebuilts/build-tools/linux-x86/bin/py3-cmd" "$TOP/build/bazel/ci/rbc_dashboard.py" aosp_arm64-userdebug
 
 # The following tests build against the full source tree and don't rely on the
diff --git a/tests/sbom_test.sh b/tests/sbom_test.sh
index 73fbeab..8dc1630 100755
--- a/tests/sbom_test.sh
+++ b/tests/sbom_test.sh
@@ -35,14 +35,15 @@
 }
 
 function run_soong {
-  target_product="$1";shift
-  out_dir="$1"; shift
-  targets="$1"; shift
+  local out_dir="$1"; shift
+  local targets="$1"; shift
   if [ "$#" -ge 1 ]; then
-    apps=$1; shift
-    TARGET_PRODUCT="${target_product}" TARGET_BUILD_VARIANT=userdebug OUT_DIR="${out_dir}" TARGET_BUILD_UNBUNDLED=true TARGET_BUILD_APPS=$apps build/soong/soong_ui.bash --make-mode ${targets}
+    local apps=$1; shift
+    TARGET_PRODUCT="${target_product}" TARGET_RELEASE="${target_release}" TARGET_BUILD_VARIANT="${target_build_variant}" OUT_DIR="${out_dir}" TARGET_BUILD_UNBUNDLED=true TARGET_BUILD_APPS=$apps \
+        build/soong/soong_ui.bash --make-mode ${targets}
   else
-    TARGET_PRODUCT="${target_product}" TARGET_BUILD_VARIANT=userdebug OUT_DIR="${out_dir}" build/soong/soong_ui.bash --make-mode ${targets}
+    TARGET_PRODUCT="${target_product}" TARGET_RELEASE="${target_release}" TARGET_BUILD_VARIANT="${target_build_variant}" OUT_DIR="${out_dir}" \
+        build/soong/soong_ui.bash --make-mode ${targets}
   fi
 }
 
@@ -67,7 +68,7 @@
 
   # Test
   # m droid, build sbom later in case additional dependencies might be built and included in partition images.
-  run_soong "aosp_cf_x86_64_phone" "${out_dir}" "droid dump.erofs lz4"
+  run_soong "${out_dir}" "droid dump.erofs lz4"
 
   product_out=$out_dir/target/product/vsoc_x86_64
   sbom_test=$product_out/sbom_test
@@ -75,7 +76,7 @@
   cp $product_out/*.img $sbom_test
 
   # m sbom
-  run_soong "aosp_cf_x86_64_phone" "${out_dir}" sbom
+  run_soong "${out_dir}" sbom
 
   # Generate installed file list from .img files in PRODUCT_OUT
   dump_erofs=$out_dir/host/linux-x86/bin/dump.erofs
@@ -217,7 +218,7 @@
   out_dir="$(setup)"
 
   # run_soong to build com.android.adbd.apex
-  run_soong "module_arm64" "${out_dir}" "sbom deapexer" "com.android.adbd"
+  run_soong "${out_dir}" "sbom deapexer" "com.android.adbd"
 
   deapexer=${out_dir}/host/linux-x86/bin/deapexer
   debugfs=${out_dir}/host/linux-x86/bin/debugfs_static
@@ -249,7 +250,7 @@
   out_dir="$(setup)"
 
   # run_soong to build Browser2.apk
-  run_soong "module_arm64" "${out_dir}" "sbom" "Browser2"
+  run_soong "${out_dir}" "sbom" "Browser2"
 
   sbom_file=${out_dir}/target/product/module_arm64/system/product/app/Browser2/Browser2.apk.spdx.json
   echo "============ Diffing files in Browser2.apk and SBOM"
@@ -271,6 +272,41 @@
   cleanup "${out_dir}"
 }
 
-test_sbom_aosp_cf_x86_64_phone
-test_sbom_unbundled_apex
-test_sbom_unbundled_apk
\ No newline at end of file
+target_product=aosp_cf_x86_64_phone
+target_release=trunk_staging
+target_build_variant=userdebug
+for i in "$@"; do
+  case $i in
+    TARGET_PRODUCT=*)
+      target_product=${i#*=}
+      shift
+      ;;
+    TARGET_RELEASE=*)
+      target_release=${i#*=}
+      shift
+      ;;
+    TARGET_BUILD_VARIANT=*)
+      target_build_variant=${i#*=}
+      shift
+      ;;
+    *)
+      echo "Unknown command line arguments: $i"
+      exit 1
+      ;;
+  esac
+done
+
+echo "target product: $target_product, target_release: $target_release, target build variant: $target_build_variant"
+case $target_product in
+  aosp_cf_x86_64_phone)
+    test_sbom_aosp_cf_x86_64_phone
+    ;;
+  module_arm64)
+    test_sbom_unbundled_apex
+    test_sbom_unbundled_apk
+    ;;
+  *)
+    echo "Unknown TARGET_PRODUCT: $target_product"
+    exit 1
+    ;;
+esac
\ No newline at end of file
diff --git a/tests/symlink_forest_rerun_test.sh b/tests/symlink_forest_rerun_test.sh
new file mode 100755
index 0000000..b704222
--- /dev/null
+++ b/tests/symlink_forest_rerun_test.sh
@@ -0,0 +1,42 @@
+#!/bin/bash -eu
+
+set -o pipefail
+
+# Tests that symlink_Forest will rerun if soong_build has schanged
+
+source "$(dirname "$0")/lib.sh"
+
+function test_symlink_forest_reruns {
+  setup
+
+  mkdir -p a
+  touch a/g.txt
+  cat > a/Android.bp <<'EOF'
+filegroup {
+    name: "g",
+    srcs: ["g.txt"],
+  }
+EOF
+
+  run_soong g
+
+  mtime=`cat out/soong/workspace/soong_build_mtime`
+  # rerun with no changes - ensure that it hasn't changed
+  run_soong g
+  newmtime=`cat out/soong/workspace/soong_build_mtime`
+  if [[ ! "$mtime" == "$mtime" ]]; then
+     fail "symlink forest reran when it shouldn't have"
+  fi
+
+  # change exit codes to force a soong_build rebuild.
+  sed -i 's/os.Exit(1)/os.Exit(2)/g' build/soong/bp2build/symlink_forest.go
+
+  run_soong g
+  newmtime=`cat out/soong/workspace/soong_build_mtime`
+  if [[ "$mtime" == "$newmtime" ]]; then
+     fail "symlink forest did not rerun when it should have"
+  fi
+
+}
+
+scan_and_run_tests
diff --git a/ui/build/build.go b/ui/build/build.go
index 14d23a7..9d5c330 100644
--- a/ui/build/build.go
+++ b/ui/build/build.go
@@ -15,11 +15,13 @@
 package build
 
 import (
+	"fmt"
 	"io/ioutil"
 	"os"
 	"path/filepath"
 	"sync"
 	"text/template"
+	"time"
 
 	"android/soong/ui/metrics"
 )
@@ -29,6 +31,7 @@
 func SetupOutDir(ctx Context, config Config) {
 	ensureEmptyFileExists(ctx, filepath.Join(config.OutDir(), "Android.mk"))
 	ensureEmptyFileExists(ctx, filepath.Join(config.OutDir(), "CleanSpec.mk"))
+	ensureEmptyDirectoriesExist(ctx, config.TempDir())
 
 	// Potentially write a marker file for whether kati is enabled. This is used by soong_build to
 	// potentially run the AndroidMk singleton and postinstall commands.
@@ -56,6 +59,31 @@
 	} else {
 		ctx.Fatalln("Missing BUILD_DATETIME_FILE")
 	}
+
+	// BUILD_NUMBER should be set to the source control value that
+	// represents the current state of the source code.  E.g., a
+	// perforce changelist number or a git hash.  Can be an arbitrary string
+	// (to allow for source control that uses something other than numbers),
+	// but must be a single word and a valid file name.
+	//
+	// If no BUILD_NUMBER is set, create a useful "I am an engineering build
+	// from this date/time" value.  Make it start with a non-digit so that
+	// anyone trying to parse it as an integer will probably get "0".
+	buildNumber, ok := config.environ.Get("BUILD_NUMBER")
+	if ok {
+		writeValueIfChanged(ctx, config, config.OutDir(), "file_name_tag.txt", buildNumber)
+	} else {
+		var username string
+		if username, ok = config.environ.Get("BUILD_USERNAME"); !ok {
+			ctx.Fatalln("Missing BUILD_USERNAME")
+		}
+		buildNumber = fmt.Sprintf("eng.%.6s.%s", username, time.Now().Format("20060102.150405" /* YYYYMMDD.HHMMSS */))
+		writeValueIfChanged(ctx, config, config.OutDir(), "file_name_tag.txt", username)
+	}
+	// Write the build number to a file so it can be read back in
+	// without changing the command line every time.  Avoids rebuilds
+	// when using ninja.
+	writeValueIfChanged(ctx, config, config.SoongOutDir(), "build_number.txt", buildNumber)
 }
 
 var combinedBuildNinjaTemplate = template.Must(template.New("combined").Parse(`
@@ -246,8 +274,6 @@
 	// checkCaseSensitivity issues a warning if a case-insensitive file system is being used.
 	checkCaseSensitivity(ctx, config)
 
-	ensureEmptyDirectoriesExist(ctx, config.TempDir())
-
 	SetupPath(ctx, config)
 
 	what := evaluateWhatToRun(config, ctx.Verboseln)
diff --git a/ui/build/config.go b/ui/build/config.go
index 084d28d..f80868c 100644
--- a/ui/build/config.go
+++ b/ui/build/config.go
@@ -22,6 +22,7 @@
 	"math/rand"
 	"os"
 	"os/exec"
+	"os/user"
 	"path/filepath"
 	"runtime"
 	"strconv"
@@ -455,6 +456,16 @@
 
 	ret.environ.Set("BUILD_DATETIME_FILE", buildDateTimeFile)
 
+	if _, ok := ret.environ.Get("BUILD_USERNAME"); !ok {
+		username := "unknown"
+		if u, err := user.Current(); err == nil {
+			username = u.Username
+		} else {
+			ctx.Println("Failed to get current user:", err)
+		}
+		ret.environ.Set("BUILD_USERNAME", username)
+	}
+
 	if ret.UseRBE() {
 		for k, v := range getRBEVars(ctx, Config{ret}) {
 			ret.environ.Set(k, v)
diff --git a/ui/build/kati.go b/ui/build/kati.go
index aea56d3..31e7440 100644
--- a/ui/build/kati.go
+++ b/ui/build/kati.go
@@ -15,6 +15,8 @@
 package build
 
 import (
+	"android/soong/ui/metrics"
+	"android/soong/ui/status"
 	"crypto/md5"
 	"fmt"
 	"io/ioutil"
@@ -22,10 +24,6 @@
 	"os/user"
 	"path/filepath"
 	"strings"
-	"time"
-
-	"android/soong/ui/metrics"
-	"android/soong/ui/status"
 )
 
 var spaceSlashReplacer = strings.NewReplacer("/", "_", " ", "_")
@@ -198,32 +196,14 @@
 		}
 	}
 	writeValueIfChanged(ctx, config, config.SoongOutDir(), "build_hostname.txt", hostname)
-
-	// BUILD_NUMBER should be set to the source control value that
-	// represents the current state of the source code.  E.g., a
-	// perforce changelist number or a git hash.  Can be an arbitrary string
-	// (to allow for source control that uses something other than numbers),
-	// but must be a single word and a valid file name.
-	//
-	// If no BUILD_NUMBER is set, create a useful "I am an engineering build
-	// from this date/time" value.  Make it start with a non-digit so that
-	// anyone trying to parse it as an integer will probably get "0".
-	cmd.Environment.Unset("HAS_BUILD_NUMBER")
-	buildNumber, ok := cmd.Environment.Get("BUILD_NUMBER")
+	_, ok = cmd.Environment.Get("BUILD_NUMBER")
 	// Unset BUILD_NUMBER during kati run to avoid kati rerun, kati will use BUILD_NUMBER from a file.
 	cmd.Environment.Unset("BUILD_NUMBER")
 	if ok {
 		cmd.Environment.Set("HAS_BUILD_NUMBER", "true")
-		writeValueIfChanged(ctx, config, config.OutDir(), "file_name_tag.txt", buildNumber)
 	} else {
-		buildNumber = fmt.Sprintf("eng.%.6s.%s", username, time.Now().Format("20060102.150405" /* YYYYMMDD.HHMMSS */))
 		cmd.Environment.Set("HAS_BUILD_NUMBER", "false")
-		writeValueIfChanged(ctx, config, config.OutDir(), "file_name_tag.txt", username)
 	}
-	// Write the build number to a file so it can be read back in
-	// without changing the command line every time.  Avoids rebuilds
-	// when using ninja.
-	writeValueIfChanged(ctx, config, config.SoongOutDir(), "build_number.txt", buildNumber)
 
 	// Apply the caller's function closure to mutate the environment variables.
 	envFunc(cmd.Environment)