Migrate GenerateProguardConfiguration from ILLink step to MSBuild task

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

@@ -22,6 +22,9 @@ This file contains the NativeAOT-specific MSBuild logic for .NET for Android.
  <DisableUnsupportedError Condition=" $([MSBuild]::IsOSPlatform('windows')) and '$(DisableUnsupportedError)' == '' ">true</DisableUnsupportedError>
  <!-- HACK: make dotnet restore include Microsoft.NETCore.App.Runtime.NativeAOT.linux-bionic-arm64 -->
  <_IsPublishing Condition=" '$(_IsPublishing)' == '' ">true</_IsPublishing>
+ <!-- ResolvedFileToPublish is not populated until _AndroidComputeIlcCompileInputs, so
+ proguard generation must run after that target instead of after ILLink. -->
+ <_GenerateProguardAfterTargets>_AndroidComputeIlcCompileInputs</_GenerateProguardAfterTargets>
  </PropertyGroup>
 
  <!-- Default property values for NativeAOT Debug configuration -->

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

@@ -6,6 +6,7 @@
  <UsingTask TaskName="Xamarin.Android.Tasks.GenerateTypeMappings" AssemblyFile="$(_XamarinAndroidBuildTasksAssembly)" />
  <UsingTask TaskName="Xamarin.Android.Tasks.GetMonoPlatformJar" AssemblyFile="$(_XamarinAndroidBuildTasksAssembly)" />
  <UsingTask TaskName="Xamarin.Android.Tasks.RemoveRegisterAttribute" AssemblyFile="$(_XamarinAndroidBuildTasksAssembly)" />
+ <UsingTask TaskName="Xamarin.Android.Tasks.GenerateProguardConfiguration" AssemblyFile="$(_XamarinAndroidBuildTasksAssembly)" />
 
  <PropertyGroup>
  <_RemoveRegisterFlag>$(MonoAndroidIntermediateAssemblyDir)shrunk\shrunk.flag</_RemoveRegisterFlag>
@@ -179,11 +180,6 @@
  -->
  <_TrimmerCustomData Include="AndroidHttpClientHandlerType" Value="$(AndroidHttpClientHandlerType)" />
  <_TrimmerCustomData Include="AndroidCustomViewMapFile" Value="$(_OuterCustomViewMapFile)" />
- <_TrimmerCustomData
- Condition=" '$(_ProguardProjectConfiguration)' != '' "
- Include="ProguardConfiguration"
- Value="$(_ProguardProjectConfiguration)"
- />
  <_TrimmerCustomData Include="SystemIOHashingAssemblyPath" Value="$(_SystemIOHashingAssemblyPath)" />
 
  <!--
@@ -200,12 +196,6 @@
  <_TrimmerCustomSteps Include="$(_AndroidLinkerCustomStepAssembly)" Type="Microsoft.Android.Sdk.ILLink.PreserveJavaInterfaces" />
  <_TrimmerCustomSteps Include="$(_AndroidLinkerCustomStepAssembly)" Type="MonoDroid.Tuner.FixAbstractMethodsStep" />
  <!-- Custom steps that run after MarkStep -->
- <_TrimmerCustomSteps
- Condition=" '$(_ProguardProjectConfiguration)' != '' "
- Include="$(_AndroidLinkerCustomStepAssembly)"
- AfterStep="CleanStep"
- Type="Mono.Linker.Steps.GenerateProguardConfiguration"
- />
  <_TrimmerCustomSteps
  Condition=" '$(AndroidAddKeepAlives)' == 'true' "
  Include="$(_AndroidLinkerCustomStepAssembly)"
@@ -350,4 +340,33 @@
  </CollectTypeMapFilesForArchive>
  </Target>
 
+ <!-- In the non-NativeAOT path, ResolvedFileToPublish is populated by the ILLink target
+ (via the SDK's ComputeResolvedFilesToPublishList), so we run proguard generation after ILLink.
+ In NativeAOT, ResolvedFileToPublish remains empty after ILLink because the ILC package's
+ _ComputeManagedAssemblyForILLink replaces ManagedAssemblyToLink after _LinkedResolvedFileToPublishCandidate
+ is computed, so the ILLink target's ResolvedFileToPublish rewrite adds nothing.
+ Instead, _AndroidComputeIlcCompileInputs populates ResolvedFileToPublish, so NativeAOT.targets
+ sets _GenerateProguardAfterTargets to run these targets after that. -->
+ <PropertyGroup>
+ <_GenerateProguardAfterTargets Condition=" '$(_GenerateProguardAfterTargets)' == '' ">ILLink</_GenerateProguardAfterTargets>
+ </PropertyGroup>
+
+ <Target Name="_PrepareLinkedAssembliesForProguard"
+ AfterTargets="$(_GenerateProguardAfterTargets)"
+ Condition=" '$(PublishTrimmed)' == 'true' and '$(_ProguardProjectConfiguration)' != '' ">
+ <ItemGroup>
+ <_LinkedAssemblyForProguard Include="@(ResolvedFileToPublish)" Condition=" '%(Extension)' == '.dll' " />
+ </ItemGroup>
+ </Target>
+
+ <Target Name="_GenerateProguardConfiguration"
+ AfterTargets="_PrepareLinkedAssembliesForProguard"
+ Condition=" '$(PublishTrimmed)' == 'true' and '$(_ProguardProjectConfiguration)' != '' "
+ Inputs="@(_LinkedAssemblyForProguard)"
+ Outputs="$(_ProguardProjectConfiguration)">
+ <GenerateProguardConfiguration
+ LinkedAssemblies="@(_LinkedAssemblyForProguard)"
+ OutputFile="$(_ProguardProjectConfiguration)" />
+ </Target>
+
 </Project>

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

@@ -0,0 +1,137 @@
+#nullable enable
+
+using System;
+using System.IO;
+using System.Reflection.Metadata;
+using System.Reflection.PortableExecutable;
+using Microsoft.Build.Framework;
+using Microsoft.Android.Build.Tasks;
+
+namespace Xamarin.Android.Tasks
+{
+	public class GenerateProguardConfiguration : AndroidTask
+	{
+ public override string TaskPrefix => "GPC";
+
+ [Required]
+ public ITaskItem[] LinkedAssemblies { get; set; } = [];
+
+ [Required]
+ public string OutputFile { get; set; } = "";
+
+ public override bool RunTask ()
+ {
+ var dir = Path.GetDirectoryName (OutputFile);
+ if (!dir.IsNullOrEmpty () && !Directory.Exists (dir)) {
+ Directory.CreateDirectory (dir);
+ }
+ using var writer = File.CreateText (OutputFile);
+
+ foreach (var assembly in LinkedAssemblies) {
+ ProcessAssembly (assembly.ItemSpec, writer);
+ }
+
+ return !Log.HasLoggedErrors;
+ }
+
+ void ProcessAssembly (string assemblyPath, TextWriter writer)
+ {
+ try {
+ using var stream = File.OpenRead (assemblyPath);
+ using var pe = new PEReader (stream);
+
+ if (!pe.HasMetadata)
+ return;
+
+ var reader = pe.GetMetadataReader ();
+
+ // Those assemblies that do not reference Mono.Android.dll (such as System.*
+ // assemblies and Mono.Android.dll itself) can be skipped.
+ // (Mono.Android.dll is special; android.jar is not part of classes.dex).
+ //
+ // FIXME: Those non-embedded jar bindings could visit here too, and they don't have to
+ // be part of proguard configuration. But they don't break (they will be NOTEd though).
+ if (!ReferencesMonoAndroid (reader))
+ return;
+
+ var assemblyName = reader.GetString (reader.GetAssemblyDefinition ().Name);
+ writer.WriteLine ($"# ACW for {assemblyName}");
+
+ foreach (var typeHandle in reader.TypeDefinitions) {
+ var type = reader.GetTypeDefinition (typeHandle);
+ ProcessType (reader, type, writer);
+ }
+ } catch (BadImageFormatException ex) {
+ // Skip non-managed assemblies
+ Log.LogDebugMessage ($"Could not read assembly '{assemblyPath}': {ex.Message}");
+ }
+ }
+
+ static bool ReferencesMonoAndroid (MetadataReader reader)
+ {
+ foreach (var refHandle in reader.AssemblyReferences) {
+ var reference = reader.GetAssemblyReference (refHandle);
+ if (reader.GetString (reference.Name) == "Mono.Android")
+ return true;
+ }
+ return false;
+ }
+
+ void ProcessType (MetadataReader reader, TypeDefinition type, TextWriter writer)
+ {
+ // RegisterAttribute can be applied to interfaces, but proguard rules are only needed for classes.
+ // Structs don't need to be checked because RegisterAttribute cannot be applied to them.
+ if ((type.Attributes & System.Reflection.TypeAttributes.Interface) != 0)
+ return;
+
+ string? javaTypeName = null;
+ foreach (var attrHandle in type.GetCustomAttributes ()) {
+ var attr = reader.GetCustomAttribute (attrHandle);
+ var attrName = reader.GetCustomAttributeFullName (attr, Log);
+ if (attrName == "Android.Runtime.RegisterAttribute") {
+ var args = attr.GetCustomAttributeArguments ();
+ if (args.FixedArguments.Length > 0 && args.FixedArguments[0].Value is string jtype) {
+ javaTypeName = jtype.Replace ('/', '.');
+ }
+ break;
+ }
+ }
+
+ if (javaTypeName == null)
+ return;
+
+ writer.WriteLine ($"-keep class {javaTypeName}");
+ writer.WriteLine ($"-keepclassmembers class {javaTypeName} {{");
+
+ foreach (var methodHandle in type.GetMethods ()) {
+ ProcessMethod (reader, methodHandle, writer);
+ }
+
+ writer.WriteLine ("}");
+ writer.WriteLine ();
+ }
+
+ void ProcessMethod (MetadataReader reader, MethodDefinitionHandle methodHandle, TextWriter writer)
+ {
+ var method = reader.GetMethodDefinition (methodHandle);
+
+ foreach (var attrHandle in method.GetCustomAttributes ()) {
+ var attr = reader.GetCustomAttribute (attrHandle);
+ var attrName = reader.GetCustomAttributeFullName (attr, Log);
+ if (attrName == "Android.Runtime.RegisterAttribute") {
+ var args = attr.GetCustomAttributeArguments ();
+ if (args.FixedArguments.Length >= 2 &&
+ args.FixedArguments[0].Value is string jname &&
+ args.FixedArguments[1].Value is string) {
+ if (jname == ".ctor") {
+ writer.WriteLine (" <init>(...);");
+ } else {
+ writer.WriteLine ($" *** {jname}(...);");
+ }
+ }
+ break;
+ }
+ }
+ }
+	}
+}