[TrimmableTypeMap] Add GenerateTrimmableTypeMap MSBuild task and targets (#10924)

* [TrimmableTypeMap] Add GenerateTrimmableTypeMap MSBuild task and targets

Add the MSBuild task that wires the TrimmableTypeMap scanner and generators
into the build pipeline, replacing the stub _GenerateJavaStubs target.

### Task (GenerateTrimmableTypeMap)
- Extends AndroidTask, TaskPrefix 'GTT'
- Scans resolved assemblies for Java peer types
- Generates per-assembly TypeMap .dll assemblies
- Generates root _Microsoft.Android.TypeMaps.dll
- Generates JCW .java source files for ACW types

### Targets
- Microsoft.Android.Sdk.TypeMap.Trimmable.targets: replaces stub with
  real GenerateTrimmableTypeMap task call
- CoreCLR.targets: adds generated assemblies as TrimmerRootAssembly,
  configures RuntimeHostConfigurationOption for TypeMappingEntryAssembly
- NativeAOT.targets: adds to IlcReference, UnmanagedEntryPointsAssembly,
  and TrimmerRootAssembly

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Add unit tests for GenerateTrimmableTypeMap task

Tests using MockBuildEngine:
- Empty assembly list succeeds with no outputs
- Real Mono.Android.dll produces per-assembly + root typemap assemblies
- Different TargetFrameworkVersion formats all parse correctly

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Add integration tests for trimmable TypeMap build pipeline

Full build integration tests:
- Build with _AndroidTypeMapImplementation=trimmable succeeds on CoreCLR
- Incremental build skips _GenerateJavaStubs when nothing changed

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Improve GenerateTrimmableTypeMap: extract methods, filter BCL, fail on bad version

- Extract Phase 1-5 into named methods (ScanAssemblies, GenerateTypeMapAssemblies,
  GenerateJcwJavaSources) — no more // Phase N comments
- Filter BCL assemblies: skip FrameworkAssembly=true unless HasMonoAndroidReference
- Throw on unparseable TargetFrameworkVersion instead of silent fallback
- Use LINQ for grouping peers by assembly and filtering paths
- Deterministic output ordering via OrderBy on assembly name

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix task return types, Java output dir, remove TrimmerRootAssembly

- Both GenerateTypeMapAssemblies and GenerateJcwJavaSources now return
  ITaskItem[] directly — no intermediate conversion in RunTask
- Move Java output under typemap dir (typemap/java instead of android/src)
- Remove TrimmerRootAssembly from generated assemblies — the trimmer must
  process TypeMapAttributes and trim entries whose trimTarget types were
  removed. TrimmerRootAssembly would prevent this, defeating the purpose.
- NativeAOT: keep IlcReference + UnmanagedEntryPointsAssembly but remove
  TrimmerRootAssembly for the same reason.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Add per-assembly timestamp check to skip up-to-date typemaps

Compare source assembly timestamp against generated typemap .dll — skip
emission when the output is newer. Root assembly only regenerated when
any per-assembly typemap changed.

Typical incremental build: only app assembly changed → scan all (for
cross-assembly resolution) but only emit _MyApp.TypeMap.dll + root.
Mono.Android scan is unavoidable (xref resolution) but its typemap
emission is skipped.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Add thorough incrementality tests for GenerateTrimmableTypeMap

- SecondRun_SkipsUpToDateAssemblies: run twice with same inputs,
  verify typemap file timestamp unchanged and 'up to date' logged
- SourceTouched_RegeneratesOnlyChangedAssembly: touch source assembly,
  verify typemap is regenerated with newer timestamp
- InvalidTargetFrameworkVersion_Throws: verify ArgumentException
- Extracted CreateTask helper to reduce test boilerplate
- ParsesTargetFrameworkVersion converted to [TestCase] parameterized test

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Document future scan optimization path in task

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Move TypeMappingEntryAssembly config to shared targets

Both CoreCLR and NativeAOT need to know the TypeMap entry assembly.
RuntimeHostConfigurationOption works for both (runtimeconfig.json for
CoreCLR, ILC feature switch for NativeAOT).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Make scanner/generator types public, fix invalid TFV test

Make types consumed by the MSBuild task public (they're build-time only,
not shipped in apps): JavaPeerInfo, MarshalMethodInfo, JniParameterInfo,
JavaConstructorInfo, ActivationCtorInfo, ActivationCtorStyle,
JavaPeerScanner, TypeMapAssemblyGenerator, RootTypeMapAssemblyGenerator,
JcwJavaSourceGenerator.

Fix Execute_InvalidTargetFrameworkVersion test: AndroidTask catches
exceptions and logs them as errors, so Assert.Throws doesn't work.
Check task.Execute() returns false and errors are logged instead.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Skip writing unchanged JCW Java files for faster incremental builds

Generate Java content to StringWriter first, compare with existing file.
Only write to disk if content changed. This avoids unnecessary javac
recompilation on incremental builds where types haven't changed.

Benchmark showed JCW file writing was the biggest bottleneck (~511ms p50
for 315 files). With this change, incremental builds that don't change
any types skip all disk writes.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Revert "Skip writing unchanged JCW Java files for faster incremental builds"

This reverts commit ac4227b.

* Move UsingTask to Trimmable.targets — only needed in trimmable path

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Sign TrimmableTypeMap assembly with product.snk

The Xamarin.Android.Build.Tasks project is strong-name signed and
references Microsoft.Android.Sdk.TrimmableTypeMap, which was not signed.
This caused CS8002 on all CI platforms.

Add SignAssembly + AssemblyOriginatorKeyFile to both the library and its
unit test project, and add the public key to the InternalsVisibleTo entry.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Address review: FileWrites, ->Count(), #nullable enable

- Add @(FileWrites) for generated typemap assemblies and Java files to
  prevent IncrementalClean from deleting them.
- Use ->Count() instead of != '' for item group empty checks in
  CoreCLR and NativeAOT targets.
- Add #nullable enable to GenerateTrimmableTypeMap.cs.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix malformed <Touch> element in Trimmable.targets

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Add test: no peers found with non-empty assembly input

Exercises the early-return path in RunTask() when the scanner finds
no [Register] types in the provided assemblies.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix FindMonoAndroidDll to use TestEnvironment.MonoAndroidFrameworkDirectory

Remove hardcoded Microsoft.Android.Ref.35 path that would break when
the API level changes. MonoAndroidFrameworkDirectory already resolves
the correct version dynamically via XABuildConfig.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Address review: use MonoAndroidHelper, leave outputs null, drop LINQ

- Leave GeneratedAssemblies/GeneratedJavaFiles null when no peers found
  instead of assigning empty arrays (review: jonathanpeppers)
- Use MonoAndroidHelper.IsMonoAndroidAssembly() instead of custom
  FrameworkAssembly/HasMonoAndroidReference logic (review: jonathanpeppers)
- Replace LINQ Select+ToArray with simple loop in GenerateJcwJavaSources
  to avoid unnecessary ITaskItem cloning (review: jonathanpeppers)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix UsingTask to use $(_XamarinAndroidBuildTasksAssembly)

The bare filename 'Xamarin.Android.Build.Tasks.dll' doesn't resolve
at runtime. All other shipped UsingTask elements use the
$(_XamarinAndroidBuildTasksAssembly) property which contains the
full path to the task assembly.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix CI: package TrimmableTypeMap DLL and add metadata to test TaskItems

Two fixes for CI test failures:

1. Integration tests (BuildWithTrimmableTypeMap*): Add
   Microsoft.Android.Sdk.TrimmableTypeMap.dll/pdb to _MSBuildFiles in
   create-installers.targets so the dependency is packaged into the
   SDK tools directory. Without this, GenerateTrimmableTypeMap task
   fails at runtime with a missing assembly error.

2. Unit tests (Execute*): FindMonoAndroidDll now returns ITaskItem
   with HasMonoAndroidReference=True metadata. The review change in
   64725e6 switched GetJavaInteropAssemblyPaths to use
   MonoAndroidHelper.IsMonoAndroidAssembly which requires metadata
   on TaskItems. Bare TaskItem(path) was rejected, causing 0
   assemblies to be scanned.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Make JavaFieldInfo record public for MSBuild task consumption

JavaFieldInfo is exposed through the public JavaPeerInfo.JavaFields property
but was not itself marked public, causing CS0050 accessibility errors when
building Xamarin.Android.Build.Tasks which references the assembly.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix integration tests: target _GenerateJavaStubs only

Full Build,SignAndroidPackage cannot succeed yet because manifest
generation (GenerateMainAndroidManifest) is not implemented for the
trimmable typemap path. Scope tests to _GenerateJavaStubs target
which validates the typemap + JCW generation that is implemented.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix CI: ensure stamp directory exists for trimmable _GenerateJavaStubs

When _GenerateJavaStubs is invoked directly (e.g., via /t:_GenerateJavaStubs
in tests), the Build target does not run, so _CleanIntermediateIfNeeded
never creates the stamp directory. The Touch task then fails because
the stamp/ directory doesn't exist.

Fix by:
1. Adding _CleanIntermediateIfNeeded to DependsOnTargets so the stamp
   directory and properties cache are created (needed for incremental
   builds).
2. Adding a defensive MakeDir before Touch as a safety net.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix CI: use full Build for trimmable typemap integration tests

Running _GenerateJavaStubs directly fails because _ResolveAssemblies
needs the compiled project DLL and Resource.Designer.dll which only
exist after a full Build. Instead, run the full Build,SignAndroidPackage
target with ThrowOnBuildFailure=false (the build fails downstream at
manifest generation, which is not yet implemented for the trimmable
path) and verify _GenerateJavaStubs ran by checking typemap outputs.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: simonrozsival

build-tools/installers/create-installers.targets

@@ -153,6 +153,8 @@
     <_MSBuildFiles Include="$(MicrosoftAndroidSdkOutDir)Microsoft.Android.Sdk.Bindings.Gradle.targets" />
     <_MSBuildFiles Include="$(MicrosoftAndroidSdkOutDir)Xamarin.Android.Build.Tasks.dll" />
     <_MSBuildFiles Include="$(MicrosoftAndroidSdkOutDir)Xamarin.Android.Build.Tasks.pdb" />
+    <_MSBuildFiles Include="$(MicrosoftAndroidSdkOutDir)Microsoft.Android.Sdk.TrimmableTypeMap.dll" />
+    <_MSBuildFiles Include="$(MicrosoftAndroidSdkOutDir)Microsoft.Android.Sdk.TrimmableTypeMap.pdb" />
     <_MSBuildFiles Include="@(_LocalizationLanguages->'$(MicrosoftAndroidSdkOutDir)%(Identity)\Microsoft.Android.Build.BaseTasks.resources.dll')" />
     <_MSBuildFiles Include="@(_LocalizationLanguages->'$(MicrosoftAndroidSdkOutDir)%(Identity)\Xamarin.Android.Build.Tasks.resources.dll')" />
     <_MSBuildFiles Include="@(_LocalizationLanguages->'$(MicrosoftAndroidSdkOutDir)%(Identity)\Xamarin.Android.Tools.AndroidSdk.resources.dll')" />

src/Microsoft.Android.Sdk.TrimmableTypeMap/Generator/JcwJavaSourceGenerator.cs

@@ -39,7 +39,7 @@ namespace Microsoft.Android.Sdk.TrimmableTypeMap;
 /// }
 /// </code>
 /// </remarks>
-sealed class JcwJavaSourceGenerator
+public sealed class JcwJavaSourceGenerator
 {
 	/// <summary>
 	/// Generates .java source files for all ACW types and writes them to the output directory.

src/Microsoft.Android.Sdk.TrimmableTypeMap/Generator/RootTypeMapAssemblyGenerator.cs

@@ -19,7 +19,7 @@ namespace Microsoft.Android.Sdk.TrimmableTypeMap;
 /// [assembly: TypeMapAssemblyTarget<Java.Lang.Object>("_MyApp.TypeMap")]
 /// </code>
 /// </remarks>
-sealed class RootTypeMapAssemblyGenerator
+public sealed class RootTypeMapAssemblyGenerator
 {
 	const string DefaultAssemblyName = "_Microsoft.Android.TypeMaps";
 

src/Microsoft.Android.Sdk.TrimmableTypeMap/Generator/TypeMapAssemblyGenerator.cs

@@ -8,7 +8,7 @@ namespace Microsoft.Android.Sdk.TrimmableTypeMap;
 /// High-level API: builds the model from peers, then emits the PE assembly.
 /// Composes <see cref="ModelBuilder"/> + <see cref="TypeMapAssemblyEmitter"/>.
 /// </summary>
-sealed class TypeMapAssemblyGenerator
+public sealed class TypeMapAssemblyGenerator
 {
 	readonly Version _systemRuntimeVersion;
 

src/Microsoft.Android.Sdk.TrimmableTypeMap/Microsoft.Android.Sdk.TrimmableTypeMap.csproj

@@ -6,12 +6,14 @@
     <Nullable>enable</Nullable>
     <WarningsAsErrors>Nullable</WarningsAsErrors>
     <RootNamespace>Microsoft.Android.Sdk.TrimmableTypeMap</RootNamespace>
+    <SignAssembly>true</SignAssembly>
+    <AssemblyOriginatorKeyFile>..\..\product.snk</AssemblyOriginatorKeyFile>
   </PropertyGroup>
 
   <ItemGroup>
     <PackageReference Include="System.IO.Hashing" Version="$(SystemIOHashingPackageVersion)" />
     <PackageReference Include="System.Reflection.Metadata" Version="$(SystemReflectionMetadataPackageVersion)" />
-    <InternalsVisibleTo Include="Microsoft.Android.Sdk.TrimmableTypeMap.Tests" />
+    <InternalsVisibleTo Include="Microsoft.Android.Sdk.TrimmableTypeMap.Tests" Key="0024000004800000940000000602000000240000525341310004000011000000438ac2a5acfbf16cbd2b2b47a62762f273df9cb2795ceccdf77d10bf508e69e7a362ea7a45455bbf3ac955e1f2e2814f144e5d817efc4c6502cc012df310783348304e3ae38573c6d658c234025821fda87a0be8a0d504df564e2c93b2b878925f42503e9d54dfef9f9586d9e6f38a305769587b1de01f6c0410328b2c9733db" />
   </ItemGroup>
 
   <ItemGroup>

src/Microsoft.Android.Sdk.TrimmableTypeMap/Scanner/JavaPeerInfo.cs

@@ -8,7 +8,7 @@ namespace Microsoft.Android.Sdk.TrimmableTypeMap;
 /// Contains all data needed by downstream generators (TypeMap IL, UCO wrappers, JCW Java sources).
 /// Generators consume this data model — they never touch PEReader/MetadataReader.
 /// </summary>
-sealed record JavaPeerInfo
+public sealed record JavaPeerInfo
 {
 	/// <summary>
 	/// JNI type name, e.g., "android/app/Activity".
@@ -124,7 +124,7 @@ sealed record JavaPeerInfo
 /// Contains all data needed to generate a UCO wrapper, a JCW native declaration,
 /// and a RegisterNatives call.
 /// </summary>
-sealed record MarshalMethodInfo
+public sealed record MarshalMethodInfo
 {
 	/// <summary>
 	/// JNI method name, e.g., "onCreate".
@@ -208,7 +208,7 @@ sealed record MarshalMethodInfo
 /// <summary>
 /// Describes a JNI parameter for UCO method generation.
 /// </summary>
-sealed record JniParameterInfo
+public sealed record JniParameterInfo
 {
 	/// <summary>
 	/// JNI type descriptor, e.g., "Landroid/os/Bundle;", "I", "Z".
@@ -224,7 +224,7 @@ sealed record JniParameterInfo
 /// <summary>
 /// Describes a Java constructor to emit in the JCW .java source file.
 /// </summary>
-sealed record JavaConstructorInfo
+public sealed record JavaConstructorInfo
 {
 	/// <summary>
 	/// JNI constructor signature, e.g., "(Landroid/content/Context;)V".
@@ -247,7 +247,7 @@ sealed record JavaConstructorInfo
 /// Describes a Java field from an [ExportField] attribute.
 /// The field is initialized by calling the annotated method.
 /// </summary>
-sealed record JavaFieldInfo
+public sealed record JavaFieldInfo
 {
 	/// <summary>
 	/// Java field name, e.g., "STATIC_INSTANCE".
@@ -278,7 +278,7 @@ sealed record JavaFieldInfo
 /// <summary>
 /// Describes how to call the activation constructor for a Java peer type.
 /// </summary>
-sealed record ActivationCtorInfo
+public sealed record ActivationCtorInfo
 {
 	/// <summary>
 	/// The type that declares the activation constructor.
@@ -297,7 +297,7 @@ sealed record ActivationCtorInfo
 	public required ActivationCtorStyle Style { get; init; }
 }
 
-enum ActivationCtorStyle
+public enum ActivationCtorStyle
 {
 	/// <summary>
 	/// Xamarin.Android style: (IntPtr handle, JniHandleOwnership transfer)

src/Microsoft.Android.Sdk.TrimmableTypeMap/Scanner/JavaPeerScanner.cs

@@ -14,7 +14,7 @@ namespace Microsoft.Android.Sdk.TrimmableTypeMap;
 ///   Phase 1: Build per-assembly indices (fast, O(1) lookups)
 ///   Phase 2: Analyze types using cached indices
 /// </summary>
-sealed class JavaPeerScanner : IDisposable
+public sealed class JavaPeerScanner : IDisposable
 {
 	readonly Dictionary<string, AssemblyIndex> assemblyCache = new (StringComparer.Ordinal);
 	readonly Dictionary<(string typeName, string assemblyName), ActivationCtorInfo> activationCtorCache = new ();

src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.CoreCLR.targets

@@ -1,5 +1,16 @@
-<!-- Trimmable typemap targets for CoreCLR runtime (stub).
-     The actual implementation will be added in a follow-up. -->
+<!-- Trimmable typemap targets for CoreCLR runtime.
+     Adds generated typemap assemblies to the linker inputs. -->
 <Project>
 
+  <!-- After typemap generation, add generated assemblies to resolved assemblies for the linker.
+       NOT as TrimmerRootAssembly — the trimmer must process TypeMapAttributes and trim entries
+       whose trimTarget types were removed. -->
+  <Target Name="_AddTrimmableTypeMapAssembliesToLinker"
+      AfterTargets="_GenerateJavaStubs"
+      Condition=" '@(_GeneratedTypeMapAssemblies->Count())' != '0' ">
+    <ItemGroup>
+      <_ResolvedAssemblies Include="@(_GeneratedTypeMapAssemblies)" />
+    </ItemGroup>
+  </Target>
+
 </Project>

src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.NativeAOT.targets

@@ -1,4 +1,17 @@
-<!-- Trimmable typemap targets for NativeAOT runtime (stub).
-     The actual implementation will be added in a follow-up. -->
+<!-- Trimmable typemap targets for NativeAOT runtime.
+     Adds generated typemap assemblies to ILC inputs. -->
 <Project>
+
+  <!-- After typemap generation, add generated assemblies to ILC inputs.
+       NOT as TrimmerRootAssembly — ILC must process TypeMapAttributes and trim entries
+       whose trimTarget types were removed. -->
+  <Target Name="_AddTrimmableTypeMapAssembliesToIlc"
+      AfterTargets="_GenerateJavaStubs"
+      Condition=" '@(_GeneratedTypeMapAssemblies->Count())' != '0' ">
+    <ItemGroup>
+      <IlcReference Include="@(_GeneratedTypeMapAssemblies)" />
+      <UnmanagedEntryPointsAssembly Include="@(_GeneratedTypeMapAssemblies)" />
+    </ItemGroup>
+  </Target>
+
 </Project>

src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.targets

@@ -1,12 +1,27 @@
 <!-- Trimmable typemap: managed type mapping instead of native binary typemaps.
-     This is a stub — the actual implementation will be added in a follow-up. -->
+     Generates per-assembly TypeMap .dll assemblies, a root _Microsoft.Android.TypeMaps.dll,
+     and JCW .java source files with registerNatives. -->
 <Project>
 
+  <UsingTask TaskName="Xamarin.Android.Tasks.GenerateTrimmableTypeMap" AssemblyFile="$(_XamarinAndroidBuildTasksAssembly)" />
+
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.Android.Sdk.TypeMap.Trimmable.CoreCLR.targets"
       Condition=" '$(_AndroidRuntime)' == 'CoreCLR' " />
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.Android.Sdk.TypeMap.Trimmable.NativeAOT.targets"
       Condition=" '$(_AndroidRuntime)' == 'NativeAOT' " />
 
+  <PropertyGroup>
+    <_TypeMapAssemblyName>_Microsoft.Android.TypeMaps</_TypeMapAssemblyName>
+    <_TypeMapOutputDirectory>$(IntermediateOutputPath)typemap\</_TypeMapOutputDirectory>
+    <_TypeMapJavaOutputDirectory>$(IntermediateOutputPath)typemap\java</_TypeMapJavaOutputDirectory>
+  </PropertyGroup>
+
+  <!-- Tell the runtime which assembly contains the TypeMap attributes -->
+  <ItemGroup>
+    <RuntimeHostConfigurationOption Include="System.Runtime.InteropServices.TypeMappingEntryAssembly"
+        Value="$(_TypeMapAssemblyName)" />
+  </ItemGroup>
+
   <Target Name="_ValidateTrimmableTypeMapRuntime"
       BeforeTargets="Build"
       Condition=" '$(_AndroidRuntime)' != 'CoreCLR' And '$(_AndroidRuntime)' != 'NativeAOT' ">
@@ -18,10 +33,25 @@
        from the Cecil-based GenerateJavaStubs task. Extracting them into a shared target
        requires decoupling from NativeCodeGenState first. See #10807. -->
   <Target Name="_GenerateJavaStubs"
-      DependsOnTargets="_SetLatestTargetFrameworkVersion;_PrepareAssemblies;_GetGenerateJavaStubsInputs"
+      DependsOnTargets="_SetLatestTargetFrameworkVersion;_CleanIntermediateIfNeeded;_PrepareAssemblies;_GetGenerateJavaStubsInputs"
       Inputs="@(_GenerateJavaStubsInputs)"
       Outputs="$(_AndroidStampDirectory)_GenerateJavaStubs.stamp">
-    <Message Text="Trimmable typemap: skipping legacy _GenerateJavaStubs" Importance="High" />
+
+    <GenerateTrimmableTypeMap
+        ResolvedAssemblies="@(_ResolvedAssemblies)"
+        OutputDirectory="$(_TypeMapOutputDirectory)"
+        JavaSourceOutputDirectory="$(_TypeMapJavaOutputDirectory)"
+        TargetFrameworkVersion="$(TargetFrameworkVersion)">
+      <Output TaskParameter="GeneratedAssemblies" ItemName="_GeneratedTypeMapAssemblies" />
+      <Output TaskParameter="GeneratedJavaFiles" ItemName="_GeneratedJavaFiles" />
+    </GenerateTrimmableTypeMap>
+
+    <ItemGroup>
+      <FileWrites Include="@(_GeneratedTypeMapAssemblies)" />
+      <FileWrites Include="@(_GeneratedJavaFiles)" />
+    </ItemGroup>
+
+    <MakeDir Directories="$(_AndroidStampDirectory)" Condition=" !Exists('$(_AndroidStampDirectory)') " />
     <Touch Files="$(_AndroidStampDirectory)_GenerateJavaStubs.stamp" AlwaysCreate="True" />
   </Target>