diff --git a/java/bootclasspath_fragment.go b/java/bootclasspath_fragment.go
index b6b179c..85c17d3 100644
--- a/java/bootclasspath_fragment.go
+++ b/java/bootclasspath_fragment.go
@@ -769,7 +769,7 @@
 	//  their own.
 	if output.SignaturePatternsPath == nil {
 		output.SignaturePatternsPath = buildRuleSignaturePatternsFile(
-			ctx, output.AllFlagsPath, []string{"*"}, nil, nil)
+			ctx, output.AllFlagsPath, []string{"*"}, nil, nil, "")
 	}
 
 	// Initialize a HiddenAPIInfo structure.
@@ -853,12 +853,10 @@
 	return false
 }
 
-// produceHiddenAPIOutput produces the hidden API all-flags.csv file (and supporting files)
-// for the fragment as well as encoding the flags in the boot dex jars.
-func (b *BootclasspathFragmentModule) produceHiddenAPIOutput(ctx android.ModuleContext, contents []android.Module, input HiddenAPIFlagInput) *HiddenAPIOutput {
+func (b *BootclasspathFragmentModule) generateHiddenApiFlagRules(ctx android.ModuleContext, contents []android.Module, input HiddenAPIFlagInput, bootDexInfoByModule bootDexInfoByModule, suffix string) HiddenAPIFlagOutput {
 	// Generate the rules to create the hidden API flags and update the supplied hiddenAPIInfo with the
 	// paths to the created files.
-	output := hiddenAPIRulesForBootclasspathFragment(ctx, contents, input)
+	flagOutput := hiddenAPIFlagRulesForBootclasspathFragment(ctx, bootDexInfoByModule, contents, input, suffix)
 
 	// If the module specifies split_packages or package_prefixes then use those to generate the
 	// signature patterns.
@@ -866,8 +864,8 @@
 	packagePrefixes := b.sourceOnlyProperties.Hidden_api.Package_prefixes
 	singlePackages := b.sourceOnlyProperties.Hidden_api.Single_packages
 	if splitPackages != nil || packagePrefixes != nil || singlePackages != nil {
-		output.SignaturePatternsPath = buildRuleSignaturePatternsFile(
-			ctx, output.AllFlagsPath, splitPackages, packagePrefixes, singlePackages)
+		flagOutput.SignaturePatternsPath = buildRuleSignaturePatternsFile(
+			ctx, flagOutput.AllFlagsPath, splitPackages, packagePrefixes, singlePackages, suffix)
 	} else if !b.isTestFragment() {
 		ctx.ModuleErrorf(`Must specify at least one of the split_packages, package_prefixes and single_packages properties
   If this is a new bootclasspath_fragment or you are unsure what to do add the
@@ -879,6 +877,49 @@
   should specify here. If you are happy with its suggestions then you can add
   the --fix option and it will fix them for you.`, b.BaseModuleName())
 	}
+	return flagOutput
+}
+
+// produceHiddenAPIOutput produces the hidden API all-flags.csv file (and supporting files)
+// for the fragment as well as encoding the flags in the boot dex jars.
+func (b *BootclasspathFragmentModule) produceHiddenAPIOutput(ctx android.ModuleContext, contents []android.Module, input HiddenAPIFlagInput) *HiddenAPIOutput {
+	// Gather information about the boot dex files for the boot libraries provided by this fragment.
+	bootDexInfoByModule := extractBootDexInfoFromModules(ctx, contents)
+
+	flagOutput := b.generateHiddenApiFlagRules(ctx, contents, input, bootDexInfoByModule, "")
+
+	encodedBootDexFilesByModule := hiddenAPIEncodeRulesForBootclasspathFragment(ctx, bootDexInfoByModule, flagOutput.AllFlagsPath)
+
+	output := &HiddenAPIOutput{
+		HiddenAPIFlagOutput:         flagOutput,
+		EncodedBootDexFilesByModule: encodedBootDexFilesByModule,
+	}
+
+	config := ctx.Config()
+	targetApiLevel := android.ApiLevelOrPanic(ctx,
+		config.GetenvWithDefault("SOONG_SDK_SNAPSHOT_TARGET_BUILD_RELEASE", "current"))
+
+	filterContents := []android.Module{}
+	for _, module := range contents {
+		minApiLevel := android.MinApiLevelForSdkSnapshot(ctx, module)
+		if minApiLevel.GreaterThan(targetApiLevel) {
+			delete(bootDexInfoByModule, module.Name())
+			delete(input.StubDexJarsByScope, module.Name())
+			continue
+		}
+
+		filterContents = append(filterContents, module)
+	}
+
+	if len(filterContents) != len(contents) {
+		flagOutput = b.generateHiddenApiFlagRules(ctx, filterContents, input, bootDexInfoByModule, "-for-sdk-snapshot")
+	}
+
+	// Copy the information and make it available for sdk snapshot.
+	ctx.SetProvider(HiddenAPIInfoForSdkProvider, HiddenAPIInfoForSdk{
+		FlagFilesByCategory: input.FlagFilesByCategory,
+		HiddenAPIFlagOutput: flagOutput,
+	})
 
 	return output
 }
@@ -1044,7 +1085,7 @@
 
 	// Get the hidden API information from the module.
 	mctx := ctx.SdkModuleContext()
-	hiddenAPIInfo := mctx.OtherModuleProvider(module, HiddenAPIInfoProvider).(HiddenAPIInfo)
+	hiddenAPIInfo := mctx.OtherModuleProvider(module, HiddenAPIInfoForSdkProvider).(HiddenAPIInfoForSdk)
 	b.Flag_files_by_category = hiddenAPIInfo.FlagFilesByCategory
 
 	// Copy all the generated file paths.
@@ -1223,6 +1264,15 @@
 	output.FilteredStubFlagsPath = pathForOptionalSrc(module.prebuiltProperties.Hidden_api.Filtered_stub_flags, output.StubFlagsPath)
 	output.FilteredFlagsPath = pathForOptionalSrc(module.prebuiltProperties.Hidden_api.Filtered_flags, output.AllFlagsPath)
 
+	// If the prebuilts module does not provide a signature patterns file then generate one from the
+	// flags.
+	// TODO(b/192868581): Remove once the prebuilts all provide a signature patterns file of their
+	//  own.
+	if output.SignaturePatternsPath == nil {
+		output.SignaturePatternsPath = buildRuleSignaturePatternsFile(
+			ctx, output.AllFlagsPath, []string{"*"}, nil, nil, "")
+	}
+
 	return &output
 }