Move marshal method pipeline from outer build to inner (per-RID) build

pr-message.md

@@ -0,0 +1,7 @@
+[marshal methods] Move marshal method pipeline from outer build to inner (per-RID) build
+
+## Summary
+
+Moves marshal method classification, assembly rewriting, and `.ll` LLVM IR generation from the outer build into the inner (per-RID) build's `RewriteMarshalMethods` task, running after ILLink trimming on already-trimmed assemblies. This eliminates the token staleness problem where classification captured token state, then rewriting mutated tokens, then downstream tasks saw stale data.
+
+When marshal methods are enabled, the task classifies, rewrites assemblies, and generates a full `.ll`. When disabled, it generates an empty/minimal `.ll` with just the structural scaffolding the native runtime links against. `GenerateNativeMarshalMethodSources` is stripped down to P/Invoke preservation only.

run-test-similar-androidx.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+# Wrapper script to run the SimilarAndroidXAssemblyNames(False,MonoVM) test case locally.
+# Usage: ./run-test-similar-androidx.sh [Configuration]
+#   Configuration defaults to "Release"
+
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+CONFIG="${1:-Release}"
+TFM="net10.0"
+DLL="$SCRIPT_DIR/bin/Test${CONFIG}/${TFM}/Xamarin.Android.Build.Tests.dll"
+
+if [[ ! -f "$DLL" ]]; then
+    echo "ERROR: Test DLL not found at: $DLL"
+    echo "       You may need to build the tests first, or pass a different Configuration."
+    exit 1
+fi
+
+echo "=== Running: SimilarAndroidXAssemblyNames(False,MonoVM) ==="
+echo "    DLL: $DLL"
+echo ""
+
+exec "$SCRIPT_DIR/dotnet-local.sh" test "$DLL" \
+    --logger "console;verbosity=detailed" \
+    -- NUnit.Where="method == SimilarAndroidXAssemblyNames and test =~ /False,MonoVM/"

run-test.sh

@@ -0,0 +1,18 @@
+#!/bin/bash
+# Run the CustomApplicationClassAndMultiDex(True,MonoVM) test locally
+# This test failed in CI with a build failure related to marshal methods pipeline changes.
+set -euo pipefail
+
+REPO_ROOT="$(cd "$(dirname "$0")" && pwd)"
+TEST_DLL="$REPO_ROOT/bin/TestRelease/net10.0/Xamarin.Android.Build.Tests.dll"
+
+if [ ! -f "$TEST_DLL" ]; then
+    echo "ERROR: Test DLL not found at $TEST_DLL"
+    echo "You may need to build the tests first."
+    exit 1
+fi
+
+echo "Running: CustomApplicationClassAndMultiDex(True,MonoVM)"
+exec "$REPO_ROOT/dotnet-local.sh" test "$TEST_DLL" \
+    --filter "Name~CustomApplicationClassAndMultiDex" \
+    -- NUnit.NumberOfTestWorkers=1

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

@@ -78,13 +78,6 @@
         EnableNativeRuntimeLinking="$(_AndroidEnableNativeRuntimeLinking)">
     </GenerateJavaStubs>
 
-    <RewriteMarshalMethods
-        Condition=" '$(_AndroidUseMarshalMethods)' == 'true' And '$(AndroidIncludeDebugSymbols)' == 'false' "
-        EnableManagedMarshalMethodsLookup="$(_AndroidUseManagedMarshalMethodsLookup)"
-        Environments="@(_EnvironmentFiles)"
-        IntermediateOutputDirectory="$(IntermediateOutputPath)">
-    </RewriteMarshalMethods>
-
     <GenerateTypeMappings
         AndroidRuntime="$(_AndroidRuntime)"
         Debug="$(AndroidIncludeDebugSymbols)"
@@ -137,6 +130,7 @@
     <GenerateAdditionalProviderSources
         AdditionalProviderSources="@(_AdditionalProviderSources)"
         AndroidRuntime="$(_AndroidRuntime)"
+        EnableMarshalMethods="$(_AndroidUseMarshalMethods)"
         Environments="@(_EnvironmentFiles)"
         HttpClientHandlerType="$(AndroidHttpClientHandlerType)"
         EnableSGenConcurrent="$(AndroidEnableSGenConcurrent)"
@@ -250,6 +244,73 @@
         Deterministic="$(Deterministic)" />
   </Target>
 
+  <!--
+    Inner-build marshal method handling.  Always runs (for every RID) to generate
+    the marshal_methods.<abi>.ll LLVM IR file.
+
+    When marshal methods are enabled (Release + MonoVM), the task also classifies
+    marshal methods, rewrites assemblies (adds [UnmanagedCallersOnly] wrappers,
+    removes connectors), and generates a full .ll with marshal method native
+    functions.  Rewritten assemblies are always written to a separate per-RID
+    output directory (never in-place), so parallel inner builds don't conflict
+    even when the input assemblies point to a shared location (e.g. the NuGet
+    runtime pack when PublishTrimmed is false).
+
+    When marshal methods are disabled (Debug, or Release without marshal methods),
+    the task generates an empty/minimal .ll containing only the structural
+    scaffolding the native runtime always links against.
+
+    Runs AfterTargets="_PostTrimmingPipeline" which is itself AfterTargets="ILLink".
+    MSBuild fires AfterTargets hooks even when the referenced target is
+    condition-skipped, so this target runs in both trimmed and untrimmed builds.
+    When trimming IS active, _PostTrimmingPipeline completes first, ensuring
+    assemblies are trimmed before any rewrite.  Runs before ReadyToRun/crossgen2
+    so that R2R images are generated from the rewritten assemblies.
+
+    The .ll file is written to $(_OuterIntermediateOutputPath)android/ so the
+    outer build's _CompileNativeAssemblySources can compile it.
+
+    Skipped for NativeAOT because it does not use .ll-based marshal methods
+    or native assembly sources (those targets are also NativeAOT-excluded).
+  -->
+  <Target Name="_RewriteMarshalMethodsInner"
+      AfterTargets="_PostTrimmingPipeline"
+      Condition=" '$(_AndroidRuntime)' != 'NativeAOT' ">
+    <ItemGroup>
+      <_MarshalMethodsAssembly Include="@(ResolvedFileToPublish)" Condition=" '%(Extension)' == '.dll' " />
+    </ItemGroup>
+    <RewriteMarshalMethods
+        Assemblies="@(_MarshalMethodsAssembly)"
+        CodeGenerationTarget="$(_AndroidJcwCodegenTarget)"
+        EnableManagedMarshalMethodsLookup="$(_AndroidUseManagedMarshalMethodsLookup)"
+        EnableMarshalMethods="$(_AndroidUseMarshalMethods)"
+        Environments="@(_EnvironmentFiles)"
+        MarshalMethodsOutputDirectory="$(_OuterIntermediateOutputPath)android"
+        RewrittenAssembliesOutputDirectory="$(IntermediateOutputPath)rewritten-marshal-methods"
+        ApplicationRegistrationOutputDirectory="$(IntermediateOutputPath)application-registration"
+        AndroidRuntime="$(_AndroidRuntime)"
+        RuntimeIdentifier="$(RuntimeIdentifier)">
+      <Output TaskParameter="RewrittenAssemblies" ItemName="_RewrittenMarshalMethodFile" />
+      <Output TaskParameter="ApplicationRegistrationJavaFile" PropertyName="_InnerBuildApplicationRegistrationJavaFile" />
+    </RewriteMarshalMethods>
+    <!-- Replace original DLL items in @(ResolvedFileToPublish) with the rewritten copies.
+         PDB files are written alongside the rewritten DLLs and are discovered by
+         ProcessAssemblies in the outer build via filesystem fallback.
+         The updated items flow back to the outer build via
+         _ComputeFilesToPublishForRuntimeIdentifiers' Returns attribute. -->
+    <ItemGroup Condition=" '@(_RewrittenMarshalMethodFile)' != '' ">
+      <ResolvedFileToPublish Remove="@(_RewrittenMarshalMethodFile->'%(OriginalItemSpec)')" />
+      <ResolvedFileToPublish Include="@(_RewrittenMarshalMethodFile)" />
+    </ItemGroup>
+    <!-- Copy ApplicationRegistration.java into the shared Java source tree so javac can find it.
+         All RIDs produce identical content; whichever inner build runs last wins (safe). -->
+    <Copy
+        Condition=" '$(_InnerBuildApplicationRegistrationJavaFile)' != '' "
+        SourceFiles="$(_InnerBuildApplicationRegistrationJavaFile)"
+        DestinationFiles="$(_OuterIntermediateOutputPath)android/src/net/dot/android/ApplicationRegistration.java"
+        SkipUnchangedFiles="true" />
+  </Target>
+
   <!-- Inject _TypeMapKind into the property cache -->
   <Target Name="_SetTypemapProperties"
       BeforeTargets="_CreatePropertiesCache">

src/Xamarin.Android.Build.Tasks/Tasks/GenerateAdditionalProviderSources.cs

@@ -37,6 +37,13 @@ public class GenerateAdditionalProviderSources : AndroidTask
 	public string? HttpClientHandlerType { get; set; }
 	public bool EnableSGenConcurrent { get; set; }
 
+	/// <summary>
+	/// When true, <c>ApplicationRegistration.java</c> is generated by the inner build's
+	/// <see cref="RewriteMarshalMethods"/> task (which has the classifier to filter types).
+	/// This task skips generating it to avoid overwriting the inner build's output.
+	/// </summary>
+	public bool EnableMarshalMethods { get; set; }
+
 	AndroidRuntime androidRuntime;
 	JavaPeerStyle codeGenerationTarget;
 
@@ -114,29 +121,34 @@ void Generate (NativeCodeGenStateObject codeGenState)
 		}
 
 		// Create additional application java sources.
-		StringWriter regCallsWriter = new StringWriter ();
-		regCallsWriter.WriteLine ("// Application and Instrumentation ACWs must be registered first.");
-
-		foreach ((string jniName, string assemblyQualifiedName) in codeGenState.ApplicationsAndInstrumentationsToRegister) {
-			regCallsWriter.WriteLine (
-				codeGenerationTarget == JavaPeerStyle.XAJavaInterop1 ?
-					"\t\tmono.android.Runtime.register (\"{0}\", {1}.class, {1}.__md_methods);" :
-					"\t\tnet.dot.jni.ManagedPeer.registerNativeMembers ({1}.class, {1}.__md_methods);",
-				assemblyQualifiedName,
-				jniName
-			);
-		}
+		// When marshal methods are enabled, ApplicationRegistration.java is generated
+		// by RewriteMarshalMethods in the inner build, which has the classifier to
+		// filter out types with no dynamically registered methods.
+		if (!EnableMarshalMethods) {
+			StringWriter regCallsWriter = new StringWriter ();
+			regCallsWriter.WriteLine ("// Application and Instrumentation ACWs must be registered first.");
+
+			foreach ((string jniName, string assemblyQualifiedName) in codeGenState.ApplicationsAndInstrumentationsToRegister) {
+				regCallsWriter.WriteLine (
+					codeGenerationTarget == JavaPeerStyle.XAJavaInterop1 ?
+						"\t\tmono.android.Runtime.register (\"{0}\", {1}.class, {1}.__md_methods);" :
+						"\t\tnet.dot.jni.ManagedPeer.registerNativeMembers ({1}.class, {1}.__md_methods);",
+					assemblyQualifiedName,
+					jniName
+				);
+			}
 
-		regCallsWriter.Close ();
+			regCallsWriter.Close ();
 
-		var real_app_dir = Path.Combine (OutputDirectory, "src", "net", "dot", "android");
-		string applicationTemplateFile = "ApplicationRegistration.java";
-		SaveResource (
-			applicationTemplateFile,
-			applicationTemplateFile,
-			real_app_dir,
-			template => template.Replace ("// REGISTER_APPLICATION_AND_INSTRUMENTATION_CLASSES_HERE", regCallsWriter.ToString ())
-		);
+			var real_app_dir = Path.Combine (OutputDirectory, "src", "net", "dot", "android");
+			string applicationTemplateFile = "ApplicationRegistration.java";
+			SaveResource (
+				applicationTemplateFile,
+				applicationTemplateFile,
+				real_app_dir,
+				template => template.Replace ("// REGISTER_APPLICATION_AND_INSTRUMENTATION_CLASSES_HERE", regCallsWriter.ToString ())
+			);
+		}
 
 		void AppendEnvVarEntry (StringBuilder sb, string value)
 		{

src/Xamarin.Android.Build.Tasks/Tasks/GenerateJavaStubs.cs

@@ -244,12 +244,10 @@ internal static Dictionary<string, ITaskItem> MaybeGetArchAssemblies (Dictionary
 				return (false, null);
 			}
 
-			MarshalMethodsCollection? marshalMethodsCollection = null;
-
-			if (useMarshalMethods)
-				marshalMethodsCollection = MarshalMethodsCollection.FromAssemblies (arch, assemblies.Values.ToList (), resolver, Log);
-
-			return (true, new NativeCodeGenState (arch, tdCache, resolver, allJavaTypes, javaTypesForJCW, marshalMethodsCollection));
+			// Marshal method classification is now done in the inner build by
+			// RewriteMarshalMethods, so we never classify here.  The NativeCodeGenState
+			// will have a null Classifier; downstream tasks must handle that.
+			return (true, new NativeCodeGenState (arch, tdCache, resolver, allJavaTypes, javaTypesForJCW, classifier: null));
 		}
 
 		(List<TypeDefinition> allJavaTypes, List<TypeDefinition> javaTypesForJCW) ScanForJavaTypes (XAAssemblyResolver res, TypeDefinitionCache cache, Dictionary<string, ITaskItem> assemblies, Dictionary<string, ITaskItem> userAssemblies, bool useMarshalMethods)