diff --git a/apex/platform_bootclasspath_test.go b/apex/platform_bootclasspath_test.go
index eaee20d..3066c79 100644
--- a/apex/platform_bootclasspath_test.go
+++ b/apex/platform_bootclasspath_test.go
@@ -159,11 +159,12 @@
 		android.AssertPathsRelativeToTopEquals(t, message, expected, info.FlagsFilesByCategory[category])
 	}
 
-	android.AssertPathsRelativeToTopEquals(t, "stub flags", []string{"out/soong/.intermediates/bar-fragment/android_common_apex10000/modular-hiddenapi/stub-flags.csv"}, info.StubFlagsPaths)
 	android.AssertPathsRelativeToTopEquals(t, "annotation flags", []string{"out/soong/.intermediates/bar-fragment/android_common_apex10000/modular-hiddenapi/annotation-flags.csv"}, info.AnnotationFlagsPaths)
 	android.AssertPathsRelativeToTopEquals(t, "metadata flags", []string{"out/soong/.intermediates/bar-fragment/android_common_apex10000/modular-hiddenapi/metadata.csv"}, info.MetadataPaths)
 	android.AssertPathsRelativeToTopEquals(t, "index flags", []string{"out/soong/.intermediates/bar-fragment/android_common_apex10000/modular-hiddenapi/index.csv"}, info.IndexPaths)
-	android.AssertPathsRelativeToTopEquals(t, "all flags", []string{"out/soong/.intermediates/bar-fragment/android_common_apex10000/modular-hiddenapi/all-flags.csv"}, info.AllFlagsPaths)
+
+	android.AssertArrayString(t, "stub flags", []string{"out/soong/.intermediates/bar-fragment/android_common_apex10000/modular-hiddenapi/stub-flags.csv:out/soong/.intermediates/bar-fragment/android_common_apex10000/modular-hiddenapi/signature-patterns.csv"}, info.StubFlagSubsets.RelativeToTop())
+	android.AssertArrayString(t, "all flags", []string{"out/soong/.intermediates/bar-fragment/android_common_apex10000/modular-hiddenapi/all-flags.csv:out/soong/.intermediates/bar-fragment/android_common_apex10000/modular-hiddenapi/signature-patterns.csv"}, info.FlagSubsets.RelativeToTop())
 }
 
 func TestPlatformBootclasspathDependencies(t *testing.T) {
diff --git a/cc/config/global.go b/cc/config/global.go
index 55e0d79..3daee38 100644
--- a/cc/config/global.go
+++ b/cc/config/global.go
@@ -46,7 +46,6 @@
 
 		"-O2",
 		"-g",
-		"-fdebug-default-version=5",
 		"-fdebug-info-for-profiling",
 
 		"-fno-strict-aliasing",
diff --git a/java/bootclasspath_fragment.go b/java/bootclasspath_fragment.go
index 107d34a..bb542c4 100644
--- a/java/bootclasspath_fragment.go
+++ b/java/bootclasspath_fragment.go
@@ -579,6 +579,14 @@
 	common := ctx.Module().(commonBootclasspathFragment)
 	output := common.produceHiddenAPIOutput(ctx, contents, input)
 
+	// If the source or prebuilts module does not provide a signature patterns file then generate one
+	// from the flags.
+	// TODO(b/192868581): Remove once the source and prebuilts provide a signature patterns file of
+	//  their own.
+	if output.SignaturePatternsPath == nil {
+		output.SignaturePatternsPath = buildRuleSignaturePatternsFile(ctx, output.AllFlagsPath)
+	}
+
 	// Initialize a HiddenAPIInfo structure.
 	hiddenAPIInfo := HiddenAPIInfo{
 		// The monolithic hidden API processing needs access to the flag files that override the default
@@ -744,9 +752,6 @@
 	// Flag files by *hiddenAPIFlagFileCategory
 	Flag_files_by_category FlagFilesByCategory
 
-	// The path to the generated stub-flags.csv file.
-	Stub_flags_path android.OptionalPath
-
 	// The path to the generated annotation-flags.csv file.
 	Annotation_flags_path android.OptionalPath
 
@@ -756,6 +761,12 @@
 	// The path to the generated index.csv file.
 	Index_path android.OptionalPath
 
+	// The path to the generated signature-patterns.csv file.
+	Signature_patterns_path android.OptionalPath
+
+	// The path to the generated stub-flags.csv file.
+	Stub_flags_path android.OptionalPath
+
 	// The path to the generated all-flags.csv file.
 	All_flags_path android.OptionalPath
 }
@@ -772,10 +783,12 @@
 	b.Flag_files_by_category = hiddenAPIInfo.FlagFilesByCategory
 
 	// Copy all the generated file paths.
-	b.Stub_flags_path = android.OptionalPathForPath(hiddenAPIInfo.StubFlagsPath)
 	b.Annotation_flags_path = android.OptionalPathForPath(hiddenAPIInfo.AnnotationFlagsPath)
 	b.Metadata_path = android.OptionalPathForPath(hiddenAPIInfo.MetadataPath)
 	b.Index_path = android.OptionalPathForPath(hiddenAPIInfo.IndexPath)
+
+	b.Signature_patterns_path = android.OptionalPathForPath(hiddenAPIInfo.SignaturePatternsPath)
+	b.Stub_flags_path = android.OptionalPathForPath(hiddenAPIInfo.StubFlagsPath)
 	b.All_flags_path = android.OptionalPathForPath(hiddenAPIInfo.AllFlagsPath)
 
 	// Copy stub_libs properties.
@@ -839,10 +852,11 @@
 	}
 
 	// Copy all the generated files, if available.
-	copyOptionalPath(b.Stub_flags_path, "stub_flags")
 	copyOptionalPath(b.Annotation_flags_path, "annotation_flags")
 	copyOptionalPath(b.Metadata_path, "metadata")
 	copyOptionalPath(b.Index_path, "index")
+	copyOptionalPath(b.Signature_patterns_path, "signature_patterns")
+	copyOptionalPath(b.Stub_flags_path, "stub_flags")
 	copyOptionalPath(b.All_flags_path, "all_flags")
 }
 
@@ -852,9 +866,6 @@
 // specific properties.
 type prebuiltBootclasspathFragmentProperties struct {
 	Hidden_api struct {
-		// The path to the stub-flags.csv file created by the bootclasspath_fragment.
-		Stub_flags *string `android:"path"`
-
 		// The path to the annotation-flags.csv file created by the bootclasspath_fragment.
 		Annotation_flags *string `android:"path"`
 
@@ -864,6 +875,12 @@
 		// The path to the index.csv file created by the bootclasspath_fragment.
 		Index *string `android:"path"`
 
+		// The path to the signature-patterns.csv file created by the bootclasspath_fragment.
+		Signature_patterns *string `android:"path"`
+
+		// The path to the stub-flags.csv file created by the bootclasspath_fragment.
+		Stub_flags *string `android:"path"`
+
 		// The path to the all-flags.csv file created by the bootclasspath_fragment.
 		All_flags *string `android:"path"`
 	}
@@ -892,6 +909,12 @@
 
 // produceHiddenAPIOutput returns a path to the prebuilt all-flags.csv or nil if none is specified.
 func (module *prebuiltBootclasspathFragmentModule) produceHiddenAPIOutput(ctx android.ModuleContext, contents []android.Module, input HiddenAPIFlagInput) *HiddenAPIOutput {
+	pathForOptionalSrc := func(src *string) android.Path {
+		if src == nil {
+			return nil
+		}
+		return android.PathForModuleSrc(ctx, *src)
+	}
 	pathForSrc := func(property string, src *string) android.Path {
 		if src == nil {
 			ctx.PropertyErrorf(property, "is required but was not specified")
@@ -906,11 +929,12 @@
 
 	output := HiddenAPIOutput{
 		HiddenAPIFlagOutput: HiddenAPIFlagOutput{
-			AnnotationFlagsPath: pathForSrc("hidden_api.annotation_flags", module.prebuiltProperties.Hidden_api.Annotation_flags),
-			MetadataPath:        pathForSrc("hidden_api.metadata", module.prebuiltProperties.Hidden_api.Metadata),
-			IndexPath:           pathForSrc("hidden_api.index", module.prebuiltProperties.Hidden_api.Index),
-			StubFlagsPath:       pathForSrc("hidden_api.stub_flags", module.prebuiltProperties.Hidden_api.Stub_flags),
-			AllFlagsPath:        pathForSrc("hidden_api.all_flags", module.prebuiltProperties.Hidden_api.All_flags),
+			AnnotationFlagsPath:   pathForSrc("hidden_api.annotation_flags", module.prebuiltProperties.Hidden_api.Annotation_flags),
+			MetadataPath:          pathForSrc("hidden_api.metadata", module.prebuiltProperties.Hidden_api.Metadata),
+			IndexPath:             pathForSrc("hidden_api.index", module.prebuiltProperties.Hidden_api.Index),
+			SignaturePatternsPath: pathForOptionalSrc(module.prebuiltProperties.Hidden_api.Signature_patterns),
+			StubFlagsPath:         pathForSrc("hidden_api.stub_flags", module.prebuiltProperties.Hidden_api.Stub_flags),
+			AllFlagsPath:          pathForSrc("hidden_api.all_flags", module.prebuiltProperties.Hidden_api.All_flags),
 		},
 		EncodedBootDexFilesByModule: encodedBootDexJarsByModule,
 	}
diff --git a/java/hiddenapi_modular.go b/java/hiddenapi_modular.go
index 86ab825..8a06a99 100644
--- a/java/hiddenapi_modular.go
+++ b/java/hiddenapi_modular.go
@@ -297,7 +297,7 @@
 //
 // The rule is initialized but not built so that the caller can modify it and select an appropriate
 // name.
-func buildRuleToGenerateHiddenAPIStubFlagsFile(ctx android.BuilderContext, name, desc string, outputPath android.WritablePath, bootDexJars android.Paths, input HiddenAPIFlagInput, moduleStubFlagsPaths android.Paths) {
+func buildRuleToGenerateHiddenAPIStubFlagsFile(ctx android.BuilderContext, name, desc string, outputPath android.WritablePath, bootDexJars android.Paths, input HiddenAPIFlagInput, stubFlagSubsets SignatureCsvSubsets) {
 	// Singleton rule which applies hiddenapi on all boot class path dex files.
 	rule := android.NewRuleBuilder(pctx, ctx)
 
@@ -317,7 +317,7 @@
 
 	// If no module stub flags paths are provided then this must be being called for a
 	// bootclasspath_fragment and not the whole platform_bootclasspath.
-	if moduleStubFlagsPaths == nil {
+	if stubFlagSubsets == nil {
 		// This is being run on a fragment of the bootclasspath.
 		command.Flag("--fragment")
 	}
@@ -342,8 +342,8 @@
 
 	// If there are stub flag files that have been generated by fragments on which this depends then
 	// use them to validate the stub flag file generated by the rules created by this method.
-	if len(moduleStubFlagsPaths) > 0 {
-		validFile := buildRuleValidateOverlappingCsvFiles(ctx, name, desc, outputPath, moduleStubFlagsPaths)
+	if len(stubFlagSubsets) > 0 {
+		validFile := buildRuleValidateOverlappingCsvFiles(ctx, name, desc, outputPath, stubFlagSubsets)
 
 		// Add the file that indicates that the file generated by this is valid.
 		//
@@ -546,6 +546,20 @@
 	}
 }
 
+// StubFlagSubset returns a SignatureCsvSubset that contains a path to a stub-flags.csv file and a
+// path to a signature-patterns.csv file that defines a subset of the monolithic stub flags file,
+// i.e. out/soong/hiddenapi/hiddenapi-stub-flags.txt, against which it will be compared.
+func (i *HiddenAPIInfo) StubFlagSubset() SignatureCsvSubset {
+	return SignatureCsvSubset{i.StubFlagsPath, i.SignaturePatternsPath}
+}
+
+// FlagSubset returns a SignatureCsvSubset that contains a path to an all-flags.csv file and a
+// path to a signature-patterns.csv file that defines a subset of the monolithic flags file, i.e.
+// out/soong/hiddenapi/hiddenapi-flags.csv, against which it will be compared.
+func (i *HiddenAPIInfo) FlagSubset() SignatureCsvSubset {
+	return SignatureCsvSubset{i.AllFlagsPath, i.SignaturePatternsPath}
+}
+
 var HiddenAPIInfoProvider = blueprint.NewProvider(HiddenAPIInfo{})
 
 // ModuleStubDexJars contains the stub dex jars provided by a single module.
@@ -782,6 +796,10 @@
 
 	// The path to the generated all-flags.csv file.
 	AllFlagsPath android.Path
+
+	// The path to the generated signature-patterns.txt file which defines the subset of the
+	// monolithic hidden API files provided in this.
+	SignaturePatternsPath android.Path
 }
 
 // bootDexJarByModule is a map from base module name (without prebuilt_ prefix) to the boot dex
@@ -848,7 +866,7 @@
 // the annotationFlags.
 func buildRuleToGenerateHiddenApiFlags(ctx android.BuilderContext, name, desc string,
 	outputPath android.WritablePath, baseFlagsPath android.Path, annotationFlagPaths android.Paths,
-	flagFilesByCategory FlagFilesByCategory, allFlagsPaths android.Paths, generatedRemovedDexSignatures android.OptionalPath) {
+	flagFilesByCategory FlagFilesByCategory, flagSubsets SignatureCsvSubsets, generatedRemovedDexSignatures android.OptionalPath) {
 
 	// Create the rule that will generate the flag files.
 	tempPath := tempPathForRestat(ctx, outputPath)
@@ -877,8 +895,8 @@
 
 	// If there are flag files that have been generated by fragments on which this depends then use
 	// them to validate the flag file generated by the rules created by this method.
-	if len(allFlagsPaths) > 0 {
-		validFile := buildRuleValidateOverlappingCsvFiles(ctx, name, desc, outputPath, allFlagsPaths)
+	if len(flagSubsets) > 0 {
+		validFile := buildRuleValidateOverlappingCsvFiles(ctx, name, desc, outputPath, flagSubsets)
 
 		// Add the file that indicates that the file generated by this is valid.
 		//
@@ -890,20 +908,66 @@
 	rule.Build(name, desc)
 }
 
+// SignatureCsvSubset describes a subset of a monolithic flags file, i.e. either
+// out/soong/hiddenapi/hiddenapi-stub-flags.txt or out/soong/hiddenapi/hiddenapi-flags.csv
+type SignatureCsvSubset struct {
+	// The path to the CSV file containing hidden API flags.
+	//
+	// It has the dex member signature as the first column, with flags, one per column, in the
+	// subsequent columns.
+	CsvFile android.Path
+
+	// The path to the CSV file containing the signature patterns.
+	//
+	// It is a single column CSV file with the column containing a signature pattern.
+	SignaturePatternsFile android.Path
+}
+
+type SignatureCsvSubsets []SignatureCsvSubset
+
+func (s SignatureCsvSubsets) RelativeToTop() []string {
+	result := []string{}
+	for _, subset := range s {
+		result = append(result, fmt.Sprintf("%s:%s", subset.CsvFile.RelativeToTop(), subset.SignaturePatternsFile.RelativeToTop()))
+	}
+	return result
+}
+
+// buildRuleSignaturePatternsFile creates a rule to generate a file containing the set of signature
+// patterns that will select a subset of the monolithic flags.
+func buildRuleSignaturePatternsFile(ctx android.ModuleContext, flagsPath android.Path) android.Path {
+	patternsFile := android.PathForModuleOut(ctx, "modular-hiddenapi", "signature-patterns.csv")
+	// Create a rule to validate the output from the following rule.
+	rule := android.NewRuleBuilder(pctx, ctx)
+	rule.Command().
+		BuiltTool("signature_patterns").
+		FlagWithInput("--flags ", flagsPath).
+		FlagWithOutput("--output ", patternsFile)
+	rule.Build("hiddenAPISignaturePatterns", "hidden API signature patterns")
+
+	return patternsFile
+}
+
 // buildRuleValidateOverlappingCsvFiles checks that the modular CSV files, i.e. the files generated
 // by the individual bootclasspath_fragment modules are subsets of the monolithic CSV file.
-func buildRuleValidateOverlappingCsvFiles(ctx android.BuilderContext, name string, desc string, monolithicFilePath android.WritablePath, modularFilePaths android.Paths) android.WritablePath {
+func buildRuleValidateOverlappingCsvFiles(ctx android.BuilderContext, name string, desc string, monolithicFilePath android.WritablePath, csvSubsets SignatureCsvSubsets) android.WritablePath {
 	// The file which is used to record that the flags file is valid.
 	validFile := pathForValidation(ctx, monolithicFilePath)
 
 	// Create a rule to validate the output from the following rule.
 	rule := android.NewRuleBuilder(pctx, ctx)
-	rule.Command().
+	command := rule.Command().
 		BuiltTool("verify_overlaps").
-		Input(monolithicFilePath).
-		Inputs(modularFilePaths).
-		// If validation passes then update the file that records that.
-		Text("&& touch").Output(validFile)
+		Input(monolithicFilePath)
+
+	for _, subset := range csvSubsets {
+		command.
+			Textf("%s:%s", subset.CsvFile, subset.SignaturePatternsFile).
+			Implicit(subset.CsvFile).Implicit(subset.SignaturePatternsFile)
+	}
+
+	// If validation passes then update the file that records that.
+	command.Text("&& touch").Output(validFile)
 	rule.Build(name+"Validation", desc+" validation")
 
 	return validFile
diff --git a/java/hiddenapi_monolithic.go b/java/hiddenapi_monolithic.go
index 404b4c1..5956e3c 100644
--- a/java/hiddenapi_monolithic.go
+++ b/java/hiddenapi_monolithic.go
@@ -29,9 +29,6 @@
 	// that category.
 	FlagsFilesByCategory FlagFilesByCategory
 
-	// The paths to the generated stub-flags.csv files.
-	StubFlagsPaths android.Paths
-
 	// The paths to the generated annotation-flags.csv files.
 	AnnotationFlagsPaths android.Paths
 
@@ -41,8 +38,13 @@
 	// The paths to the generated index.csv files.
 	IndexPaths android.Paths
 
-	// The paths to the generated all-flags.csv files.
-	AllFlagsPaths android.Paths
+	// The subsets of the monolithic hiddenapi-stubs-flags.txt file that are provided by each
+	// bootclasspath_fragment modules.
+	StubFlagSubsets SignatureCsvSubsets
+
+	// The subsets of the monolithic hiddenapi-flags.csv file that are provided by each
+	// bootclasspath_fragment modules.
+	FlagSubsets SignatureCsvSubsets
 
 	// The classes jars from the libraries on the platform bootclasspath.
 	ClassesJars android.Paths
@@ -80,11 +82,12 @@
 // append appends all the files from the supplied info to the corresponding files in this struct.
 func (i *MonolithicHiddenAPIInfo) append(other *HiddenAPIInfo) {
 	i.FlagsFilesByCategory.append(other.FlagFilesByCategory)
-	i.StubFlagsPaths = append(i.StubFlagsPaths, other.StubFlagsPath)
 	i.AnnotationFlagsPaths = append(i.AnnotationFlagsPaths, other.AnnotationFlagsPath)
 	i.MetadataPaths = append(i.MetadataPaths, other.MetadataPath)
 	i.IndexPaths = append(i.IndexPaths, other.IndexPath)
-	i.AllFlagsPaths = append(i.AllFlagsPaths, other.AllFlagsPath)
+
+	i.StubFlagSubsets = append(i.StubFlagSubsets, other.StubFlagSubset())
+	i.FlagSubsets = append(i.FlagSubsets, other.FlagSubset())
 }
 
 var MonolithicHiddenAPIInfoProvider = blueprint.NewProvider(MonolithicHiddenAPIInfo{})
diff --git a/java/platform_bootclasspath.go b/java/platform_bootclasspath.go
index 3ff4c77..36baf7e 100644
--- a/java/platform_bootclasspath.go
+++ b/java/platform_bootclasspath.go
@@ -316,7 +316,7 @@
 
 	// Generate the monolithic stub-flags.csv file.
 	stubFlags := hiddenAPISingletonPaths(ctx).stubFlags
-	buildRuleToGenerateHiddenAPIStubFlagsFile(ctx, "platform-bootclasspath-monolithic-hiddenapi-stub-flags", "monolithic hidden API stub flags", stubFlags, bootDexJarByModule.bootDexJars(), input, monolithicInfo.StubFlagsPaths)
+	buildRuleToGenerateHiddenAPIStubFlagsFile(ctx, "platform-bootclasspath-monolithic-hiddenapi-stub-flags", "monolithic hidden API stub flags", stubFlags, bootDexJarByModule.bootDexJars(), input, monolithicInfo.StubFlagSubsets)
 
 	// Generate the annotation-flags.csv file from all the module annotations.
 	annotationFlags := android.PathForModuleOut(ctx, "hiddenapi-monolithic", "annotation-flags-from-classes.csv")
@@ -329,7 +329,7 @@
 	allAnnotationFlagFiles := android.Paths{annotationFlags}
 	allAnnotationFlagFiles = append(allAnnotationFlagFiles, monolithicInfo.AnnotationFlagsPaths...)
 	allFlags := hiddenAPISingletonPaths(ctx).flags
-	buildRuleToGenerateHiddenApiFlags(ctx, "hiddenAPIFlagsFile", "monolithic hidden API flags", allFlags, stubFlags, allAnnotationFlagFiles, monolithicInfo.FlagsFilesByCategory, monolithicInfo.AllFlagsPaths, android.OptionalPath{})
+	buildRuleToGenerateHiddenApiFlags(ctx, "hiddenAPIFlagsFile", "monolithic hidden API flags", allFlags, stubFlags, allAnnotationFlagFiles, monolithicInfo.FlagsFilesByCategory, monolithicInfo.FlagSubsets, android.OptionalPath{})
 
 	// Generate an intermediate monolithic hiddenapi-metadata.csv file directly from the annotations
 	// in the source code.
diff --git a/scripts/hiddenapi/Android.bp b/scripts/hiddenapi/Android.bp
index c50dc24..7ffda62 100644
--- a/scripts/hiddenapi/Android.bp
+++ b/scripts/hiddenapi/Android.bp
@@ -83,3 +83,60 @@
         },
     },
 }
+
+python_test_host {
+    name: "verify_overlaps_test",
+    main: "verify_overlaps_test.py",
+    srcs: [
+        "verify_overlaps.py",
+        "verify_overlaps_test.py",
+    ],
+    version: {
+        py2: {
+            enabled: false,
+        },
+        py3: {
+            enabled: true,
+            embedded_launcher: true,
+        },
+    },
+    test_options: {
+        unit_test: true,
+    },
+}
+
+python_binary_host {
+    name: "signature_patterns",
+    main: "signature_patterns.py",
+    srcs: ["signature_patterns.py"],
+    version: {
+        py2: {
+            enabled: false,
+        },
+        py3: {
+            enabled: true,
+            embedded_launcher: true,
+        },
+    },
+}
+
+python_test_host {
+    name: "signature_patterns_test",
+    main: "signature_patterns_test.py",
+    srcs: [
+        "signature_patterns.py",
+        "signature_patterns_test.py",
+    ],
+    version: {
+        py2: {
+            enabled: false,
+        },
+        py3: {
+            enabled: true,
+            embedded_launcher: true,
+        },
+    },
+    test_options: {
+        unit_test: true,
+    },
+}
diff --git a/scripts/hiddenapi/signature_patterns.py b/scripts/hiddenapi/signature_patterns.py
new file mode 100755
index 0000000..91328e6
--- /dev/null
+++ b/scripts/hiddenapi/signature_patterns.py
@@ -0,0 +1,56 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2021 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""
+Generate a set of signature patterns from the modular flags generated by a
+bootclasspath_fragment that can be used to select a subset of monolithic flags
+against which the modular flags can be compared.
+"""
+
+import argparse
+import csv
+
+def dict_reader(input):
+    return csv.DictReader(input, delimiter=',', quotechar='|', fieldnames=['signature'])
+
+def produce_patterns_from_file(file):
+    with open(file, 'r') as f:
+        return produce_patterns_from_stream(f)
+
+def produce_patterns_from_stream(stream):
+    patterns = []
+    allFlagsReader = dict_reader(stream)
+    for row in allFlagsReader:
+        signature = row['signature']
+        patterns.append(signature)
+    return patterns
+
+def main(args):
+    args_parser = argparse.ArgumentParser(description='Generate a set of signature patterns that select a subset of monolithic hidden API files.')
+    args_parser.add_argument('--flags', help='The stub flags file which contains an entry for every dex member')
+    args_parser.add_argument('--output', help='Generated signature prefixes')
+    args = args_parser.parse_args(args)
+
+    # Read in all the patterns into a list.
+    patterns = produce_patterns_from_file(args.flags)
+
+    # Write out all the patterns.
+    with open(args.output, 'w') as outputFile:
+        for pattern in patterns:
+            outputFile.write(pattern)
+            outputFile.write("\n")
+
+if __name__ == "__main__":
+    main(sys.argv[1:])
diff --git a/scripts/hiddenapi/signature_patterns_test.py b/scripts/hiddenapi/signature_patterns_test.py
new file mode 100755
index 0000000..83c9db2
--- /dev/null
+++ b/scripts/hiddenapi/signature_patterns_test.py
@@ -0,0 +1,41 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2021 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the 'License');
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an 'AS IS' BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Unit tests for signature_patterns.py."""
+import io
+import unittest
+
+from signature_patterns import *
+
+class TestGeneratedPatterns(unittest.TestCase):
+
+    def produce_patterns_from_string(self, csv):
+        with io.StringIO(csv) as f:
+            return produce_patterns_from_stream(f)
+
+    def test_generate(self):
+        patterns = self.produce_patterns_from_string('''
+Ljava/lang/Object;->hashCode()I,public-api,system-api,test-api
+Ljava/lang/Object;->toString()Ljava/lang/String;,blocked
+''')
+        expected = [
+            "Ljava/lang/Object;->hashCode()I",
+            "Ljava/lang/Object;->toString()Ljava/lang/String;",
+        ]
+        self.assertEqual(expected, patterns)
+
+if __name__ == '__main__':
+    unittest.main(verbosity=2)
diff --git a/scripts/hiddenapi/verify_overlaps.py b/scripts/hiddenapi/verify_overlaps.py
index bb0917e..8579321 100755
--- a/scripts/hiddenapi/verify_overlaps.py
+++ b/scripts/hiddenapi/verify_overlaps.py
@@ -19,51 +19,123 @@
 
 import argparse
 import csv
-
-args_parser = argparse.ArgumentParser(description='Verify that one set of hidden API flags is a subset of another.')
-args_parser.add_argument('all', help='All the flags')
-args_parser.add_argument('subsets', nargs=argparse.REMAINDER, help='Subsets of the flags')
-args = args_parser.parse_args()
-
+from itertools import chain
 
 def dict_reader(input):
     return csv.DictReader(input, delimiter=',', quotechar='|', fieldnames=['signature'])
 
-# Read in all the flags into a dict indexed by signature
-allFlagsBySignature = {}
-with open(args.all, 'r') as allFlagsFile:
-    allFlagsReader = dict_reader(allFlagsFile)
-    for row in allFlagsReader:
+def extract_subset_from_monolithic_flags_as_dict_from_file(monolithicFlagsDict, patternsFile):
+    """
+    Extract a subset of flags from the dict containing all the monolithic flags.
+
+    :param monolithicFlagsDict: the dict containing all the monolithic flags.
+    :param patternsFile: a file containing a list of signature patterns that
+    define the subset.
+    :return: the dict from signature to row.
+    """
+    with open(patternsFile, 'r') as stream:
+        return extract_subset_from_monolithic_flags_as_dict_from_stream(monolithicFlagsDict, stream)
+
+def extract_subset_from_monolithic_flags_as_dict_from_stream(monolithicFlagsDict, stream):
+    """
+    Extract a subset of flags from the dict containing all the monolithic flags.
+
+    :param monolithicFlagsDict: the dict containing all the monolithic flags.
+    :param stream: a stream containing a list of signature patterns that define
+    the subset.
+    :return: the dict from signature to row.
+    """
+    dict = {}
+    for signature in stream:
+        signature = signature.rstrip()
+        dict[signature] = monolithicFlagsDict.get(signature, {})
+    return dict
+
+def read_signature_csv_from_stream_as_dict(stream):
+    """
+    Read the csv contents from the stream into a dict. The first column is assumed to be the
+    signature and used as the key. The whole row is stored as the value.
+
+    :param stream: the csv contents to read
+    :return: the dict from signature to row.
+    """
+    dict = {}
+    reader = dict_reader(stream)
+    for row in reader:
         signature = row['signature']
-        allFlagsBySignature[signature]=row
+        dict[signature] = row
+    return dict
 
-failed = False
-for subsetPath in args.subsets:
+def read_signature_csv_from_file_as_dict(csvFile):
+    """
+    Read the csvFile into a dict. The first column is assumed to be the
+    signature and used as the key. The whole row is stored as the value.
+
+    :param csvFile: the csv file to read
+    :return: the dict from signature to row.
+    """
+    with open(csvFile, 'r') as f:
+        return read_signature_csv_from_stream_as_dict(f)
+
+def compare_signature_flags(monolithicFlagsDict, modularFlagsDict):
+    """
+    Compare the signature flags between the two dicts.
+
+    :param monolithicFlagsDict: the dict containing the subset of the monolithic
+    flags that should be equal to the modular flags.
+    :param modularFlagsDict:the dict containing the flags produced by a single
+    bootclasspath_fragment module.
+    :return: list of mismatches., each mismatch is a tuple where the first item
+    is the signature, and the second and third items are lists of the flags from
+    modular dict, and monolithic dict respectively.
+    """
     mismatchingSignatures = []
-    with open(subsetPath, 'r') as subsetFlagsFile:
-        subsetReader = dict_reader(subsetFlagsFile)
-        for row in subsetReader:
-            signature = row['signature']
-            if signature in allFlagsBySignature:
-                allFlags = allFlagsBySignature.get(signature)
-                if allFlags != row:
-                    mismatchingSignatures.append((signature, row.get(None, []), allFlags.get(None, [])))
-            else:
-                mismatchingSignatures.append((signature, row.get(None, []), []))
+    # Create a sorted set of all the signatures from both the monolithic and
+    # modular dicts.
+    allSignatures = sorted(set(chain(monolithicFlagsDict.keys(), modularFlagsDict.keys())))
+    for signature in allSignatures:
+        monolithicRow = monolithicFlagsDict.get(signature, {})
+        monolithicFlags = monolithicRow.get(None, [])
+        modularRow = modularFlagsDict.get(signature, {})
+        modularFlags = modularRow.get(None, [])
+        if monolithicFlags != modularFlags:
+            mismatchingSignatures.append((signature, modularFlags, monolithicFlags))
+    return mismatchingSignatures
 
+def main(argv):
+    args_parser = argparse.ArgumentParser(description='Verify that sets of hidden API flags are each a subset of the monolithic flag file.')
+    args_parser.add_argument('monolithicFlags', help='The monolithic flag file')
+    args_parser.add_argument('modularFlags', nargs=argparse.REMAINDER, help='Flags produced by individual bootclasspath_fragment modules')
+    args = args_parser.parse_args(argv[1:])
 
-    if mismatchingSignatures:
-        failed = True
-        print("ERROR: Hidden API flags are inconsistent:")
-        print("< " + subsetPath)
-        print("> " + args.all)
-        for mismatch in mismatchingSignatures:
-            print()
-            print("< " + mismatch[0] + "," + ",".join(mismatch[1]))
-            if mismatch[2] != []:
-                print("> " + mismatch[0] + "," + ",".join(mismatch[2]))
-            else:
-                print("> " + mismatch[0] + " - missing")
+    # Read in the monolithic flags into a dict indexed by signature
+    monolithicFlagsPath = args.monolithicFlags
+    monolithicFlagsDict = read_signature_csv_from_file_as_dict(monolithicFlagsPath)
 
-if failed:
-    sys.exit(1)
+    # For each subset specified on the command line, create dicts for the flags
+    # provided by the subset and the corresponding flags from the complete set of
+    # flags and compare them.
+    failed = False
+    for modularPair in args.modularFlags:
+        parts = modularPair.split(":")
+        modularFlagsPath = parts[0]
+        modularPatternsPath = parts[1]
+        modularFlagsDict = read_signature_csv_from_file_as_dict(modularFlagsPath)
+        monolithicFlagsSubsetDict = extract_subset_from_monolithic_flags_as_dict_from_file(monolithicFlagsDict, modularPatternsPath)
+        mismatchingSignatures = compare_signature_flags(monolithicFlagsSubsetDict, modularFlagsDict)
+        if mismatchingSignatures:
+            failed = True
+            print("ERROR: Hidden API flags are inconsistent:")
+            print("< " + modularFlagsPath)
+            print("> " + monolithicFlagsPath)
+            for mismatch in mismatchingSignatures:
+                signature = mismatch[0]
+                print()
+                print("< " + ",".join([signature]+ mismatch[1]))
+                print("> " + ",".join([signature]+ mismatch[2]))
+
+    if failed:
+        sys.exit(1)
+
+if __name__ == "__main__":
+    main(sys.argv)
diff --git a/scripts/hiddenapi/verify_overlaps_test.py b/scripts/hiddenapi/verify_overlaps_test.py
new file mode 100755
index 0000000..b6d5fa3
--- /dev/null
+++ b/scripts/hiddenapi/verify_overlaps_test.py
@@ -0,0 +1,164 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2021 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the 'License');
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an 'AS IS' BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Unit tests for verify_overlaps_test.py."""
+import io
+import unittest
+
+from verify_overlaps import *
+
+class TestDetectOverlaps(unittest.TestCase):
+
+    def read_signature_csv_from_string_as_dict(self, csv):
+        with io.StringIO(csv) as f:
+            return read_signature_csv_from_stream_as_dict(f)
+
+    def extract_subset_from_monolithic_flags_as_dict_from_string(self, monolithic, patterns):
+        with io.StringIO(patterns) as f:
+            return extract_subset_from_monolithic_flags_as_dict_from_stream(monolithic, f)
+
+    extractInput = '''
+Ljava/lang/Object;->hashCode()I,public-api,system-api,test-api
+Ljava/lang/Object;->toString()Ljava/lang/String;,blocked
+'''
+
+    def test_extract_subset(self):
+        monolithic = self.read_signature_csv_from_string_as_dict(TestDetectOverlaps.extractInput)
+        modular = self.read_signature_csv_from_string_as_dict('''
+Ljava/lang/Object;->hashCode()I,public-api,system-api,test-api
+''')
+
+        patterns = 'Ljava/lang/Object;->hashCode()I'
+
+        subset = self.extract_subset_from_monolithic_flags_as_dict_from_string(monolithic, patterns)
+        expected = {
+            'Ljava/lang/Object;->hashCode()I': {
+                None: ['public-api', 'system-api', 'test-api'],
+                'signature': 'Ljava/lang/Object;->hashCode()I',
+            },
+        }
+        self.assertEqual(expected, subset)
+
+    def test_match(self):
+        monolithic = self.read_signature_csv_from_string_as_dict('''
+Ljava/lang/Object;->hashCode()I,public-api,system-api,test-api
+''')
+        modular = self.read_signature_csv_from_string_as_dict('''
+Ljava/lang/Object;->hashCode()I,public-api,system-api,test-api
+''')
+        mismatches = compare_signature_flags(monolithic, modular)
+        expected = []
+        self.assertEqual(expected, mismatches)
+
+    def test_mismatch_overlapping_flags(self):
+        monolithic = self.read_signature_csv_from_string_as_dict('''
+Ljava/lang/Object;->toString()Ljava/lang/String;,public-api
+''')
+        modular = self.read_signature_csv_from_string_as_dict('''
+Ljava/lang/Object;->toString()Ljava/lang/String;,public-api,system-api,test-api
+''')
+        mismatches = compare_signature_flags(monolithic, modular)
+        expected = [
+            (
+                'Ljava/lang/Object;->toString()Ljava/lang/String;',
+                ['public-api', 'system-api', 'test-api'],
+                ['public-api'],
+            ),
+        ]
+        self.assertEqual(expected, mismatches)
+
+
+    def test_mismatch_monolithic_blocked(self):
+        monolithic = self.read_signature_csv_from_string_as_dict('''
+Ljava/lang/Object;->toString()Ljava/lang/String;,blocked
+''')
+        modular = self.read_signature_csv_from_string_as_dict('''
+Ljava/lang/Object;->toString()Ljava/lang/String;,public-api,system-api,test-api
+''')
+        mismatches = compare_signature_flags(monolithic, modular)
+        expected = [
+            (
+                'Ljava/lang/Object;->toString()Ljava/lang/String;',
+                ['public-api', 'system-api', 'test-api'],
+                ['blocked'],
+            ),
+        ]
+        self.assertEqual(expected, mismatches)
+
+    def test_mismatch_modular_blocked(self):
+        monolithic = self.read_signature_csv_from_string_as_dict('''
+Ljava/lang/Object;->toString()Ljava/lang/String;,public-api,system-api,test-api
+''')
+        modular = self.read_signature_csv_from_string_as_dict('''
+Ljava/lang/Object;->toString()Ljava/lang/String;,blocked
+''')
+        mismatches = compare_signature_flags(monolithic, modular)
+        expected = [
+            (
+                'Ljava/lang/Object;->toString()Ljava/lang/String;',
+                ['blocked'],
+                ['public-api', 'system-api', 'test-api'],
+            ),
+        ]
+        self.assertEqual(expected, mismatches)
+
+    def test_missing_from_monolithic(self):
+        monolithic = self.read_signature_csv_from_string_as_dict('')
+        modular = self.read_signature_csv_from_string_as_dict('''
+Ljava/lang/Object;->toString()Ljava/lang/String;,public-api,system-api,test-api
+''')
+        mismatches = compare_signature_flags(monolithic, modular)
+        expected = [
+            (
+                'Ljava/lang/Object;->toString()Ljava/lang/String;',
+                ['public-api', 'system-api', 'test-api'],
+                [],
+            ),
+        ]
+        self.assertEqual(expected, mismatches)
+
+    def test_missing_from_modular(self):
+        monolithic = self.read_signature_csv_from_string_as_dict('''
+Ljava/lang/Object;->hashCode()I,public-api,system-api,test-api
+''')
+        modular = {}
+        mismatches = compare_signature_flags(monolithic, modular)
+        expected = [
+            (
+                'Ljava/lang/Object;->hashCode()I',
+                [],
+                ['public-api', 'system-api', 'test-api'],
+            ),
+        ]
+        self.assertEqual(expected, mismatches)
+
+    def test_blocked_missing_from_modular(self):
+        monolithic = self.read_signature_csv_from_string_as_dict('''
+Ljava/lang/Object;->hashCode()I,blocked
+''')
+        modular = {}
+        mismatches = compare_signature_flags(monolithic, modular)
+        expected = [
+            (
+                'Ljava/lang/Object;->hashCode()I',
+                [],
+                ['blocked'],
+            ),
+        ]
+        self.assertEqual(expected, mismatches)
+
+if __name__ == '__main__':
+    unittest.main(verbosity=2)
diff --git a/sdk/bootclasspath_fragment_sdk_test.go b/sdk/bootclasspath_fragment_sdk_test.go
index c7ad798..9166109 100644
--- a/sdk/bootclasspath_fragment_sdk_test.go
+++ b/sdk/bootclasspath_fragment_sdk_test.go
@@ -134,10 +134,11 @@
     image_name: "art",
     contents: ["mybootlib"],
     hidden_api: {
-        stub_flags: "hiddenapi/stub-flags.csv",
         annotation_flags: "hiddenapi/annotation-flags.csv",
         metadata: "hiddenapi/metadata.csv",
         index: "hiddenapi/index.csv",
+        signature_patterns: "hiddenapi/signature-patterns.csv",
+        stub_flags: "hiddenapi/stub-flags.csv",
         all_flags: "hiddenapi/all-flags.csv",
     },
 }
@@ -161,10 +162,11 @@
     image_name: "art",
     contents: ["mysdk_mybootlib@current"],
     hidden_api: {
-        stub_flags: "hiddenapi/stub-flags.csv",
         annotation_flags: "hiddenapi/annotation-flags.csv",
         metadata: "hiddenapi/metadata.csv",
         index: "hiddenapi/index.csv",
+        signature_patterns: "hiddenapi/signature-patterns.csv",
+        stub_flags: "hiddenapi/stub-flags.csv",
         all_flags: "hiddenapi/all-flags.csv",
     },
 }
@@ -185,10 +187,11 @@
 }
 `),
 		checkAllCopyRules(`
-.intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/stub-flags.csv -> hiddenapi/stub-flags.csv
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/annotation-flags.csv -> hiddenapi/annotation-flags.csv
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/metadata.csv -> hiddenapi/metadata.csv
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/index.csv -> hiddenapi/index.csv
+.intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/signature-patterns.csv -> hiddenapi/signature-patterns.csv
+.intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/stub-flags.csv -> hiddenapi/stub-flags.csv
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/all-flags.csv -> hiddenapi/all-flags.csv
 .intermediates/mysdk/common_os/empty -> java_boot_libs/snapshot/jars/are/invalid/mybootlib.jar
 		`),
@@ -332,10 +335,11 @@
         stub_libs: ["mycoreplatform"],
     },
     hidden_api: {
-        stub_flags: "hiddenapi/stub-flags.csv",
         annotation_flags: "hiddenapi/annotation-flags.csv",
         metadata: "hiddenapi/metadata.csv",
         index: "hiddenapi/index.csv",
+        signature_patterns: "hiddenapi/signature-patterns.csv",
+        stub_flags: "hiddenapi/stub-flags.csv",
         all_flags: "hiddenapi/all-flags.csv",
     },
 }
@@ -416,10 +420,11 @@
         stub_libs: ["mysdk_mycoreplatform@current"],
     },
     hidden_api: {
-        stub_flags: "hiddenapi/stub-flags.csv",
         annotation_flags: "hiddenapi/annotation-flags.csv",
         metadata: "hiddenapi/metadata.csv",
         index: "hiddenapi/index.csv",
+        signature_patterns: "hiddenapi/signature-patterns.csv",
+        stub_flags: "hiddenapi/stub-flags.csv",
         all_flags: "hiddenapi/all-flags.csv",
     },
 }
@@ -494,10 +499,11 @@
 }
 		`),
 		checkAllCopyRules(`
-.intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/stub-flags.csv -> hiddenapi/stub-flags.csv
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/annotation-flags.csv -> hiddenapi/annotation-flags.csv
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/metadata.csv -> hiddenapi/metadata.csv
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/index.csv -> hiddenapi/index.csv
+.intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/signature-patterns.csv -> hiddenapi/signature-patterns.csv
+.intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/stub-flags.csv -> hiddenapi/stub-flags.csv
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/all-flags.csv -> hiddenapi/all-flags.csv
 .intermediates/mysdk/common_os/empty -> java_boot_libs/snapshot/jars/are/invalid/mybootlib.jar
 .intermediates/myothersdklibrary.stubs/android_common/javac/myothersdklibrary.stubs.jar -> sdk_library/public/myothersdklibrary-stubs.jar
@@ -538,8 +544,16 @@
 			rule = module.Output("updatable-bcp-packages.txt")
 			expectedContents := `'mybootlib\nmyothersdklibrary\n'`
 			android.AssertStringEquals(t, "updatable-bcp-packages.txt", expectedContents, rule.Args["content"])
+
+			rule = module.Output("out/soong/hiddenapi/hiddenapi-flags.csv.valid")
+			android.AssertStringDoesContain(t, "verify-overlaps", rule.RuleParams.Command, " snapshot/hiddenapi/all-flags.csv:snapshot/hiddenapi/signature-patterns.csv ")
 		}),
 		snapshotTestPreparer(checkSnapshotWithSourcePreferred, preparerForSnapshot),
+		snapshotTestChecker(checkSnapshotWithSourcePreferred, func(t *testing.T, result *android.TestResult) {
+			module := result.ModuleForTests("platform-bootclasspath", "android_common")
+			rule := module.Output("out/soong/hiddenapi/hiddenapi-flags.csv.valid")
+			android.AssertStringDoesContain(t, "verify-overlaps", rule.RuleParams.Command, " out/soong/.intermediates/mybootclasspathfragment/android_common_myapex/modular-hiddenapi/all-flags.csv:out/soong/.intermediates/mybootclasspathfragment/android_common_myapex/modular-hiddenapi/signature-patterns.csv ")
+		}),
 		snapshotTestPreparer(checkSnapshotPreferredWithSource, preparerForSnapshot),
 	)
 }
@@ -636,10 +650,11 @@
         },
     ],
     hidden_api: {
-        stub_flags: "hiddenapi/stub-flags.csv",
         annotation_flags: "hiddenapi/annotation-flags.csv",
         metadata: "hiddenapi/metadata.csv",
         index: "hiddenapi/index.csv",
+        signature_patterns: "hiddenapi/signature-patterns.csv",
+        stub_flags: "hiddenapi/stub-flags.csv",
         all_flags: "hiddenapi/all-flags.csv",
     },
 }
@@ -838,10 +853,11 @@
         max_target_o_low_priority: ["hiddenapi/my-max-target-o-low-priority.txt"],
         blocked: ["hiddenapi/my-blocked.txt"],
         unsupported_packages: ["hiddenapi/my-unsupported-packages.txt"],
-        stub_flags: "hiddenapi/stub-flags.csv",
         annotation_flags: "hiddenapi/annotation-flags.csv",
         metadata: "hiddenapi/metadata.csv",
         index: "hiddenapi/index.csv",
+        signature_patterns: "hiddenapi/signature-patterns.csv",
+        stub_flags: "hiddenapi/stub-flags.csv",
         all_flags: "hiddenapi/all-flags.csv",
     },
 }
@@ -881,10 +897,11 @@
 my-max-target-o-low-priority.txt -> hiddenapi/my-max-target-o-low-priority.txt
 my-blocked.txt -> hiddenapi/my-blocked.txt
 my-unsupported-packages.txt -> hiddenapi/my-unsupported-packages.txt
-.intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/stub-flags.csv -> hiddenapi/stub-flags.csv
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/annotation-flags.csv -> hiddenapi/annotation-flags.csv
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/metadata.csv -> hiddenapi/metadata.csv
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/index.csv -> hiddenapi/index.csv
+.intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/signature-patterns.csv -> hiddenapi/signature-patterns.csv
+.intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/stub-flags.csv -> hiddenapi/stub-flags.csv
 .intermediates/mybootclasspathfragment/android_common/modular-hiddenapi/all-flags.csv -> hiddenapi/all-flags.csv
 .intermediates/mysdk/common_os/empty -> java_boot_libs/snapshot/jars/are/invalid/mybootlib.jar
 .intermediates/mysdklibrary.stubs/android_common/javac/mysdklibrary.stubs.jar -> sdk_library/public/mysdklibrary-stubs.jar