Move AddKeepAlives trimmer step to standalone MSBuild task

src/Microsoft.Android.Sdk.ILLink/Microsoft.Android.Sdk.ILLink.csproj

@@ -14,7 +14,6 @@
 
     <!--Include shared linker sources-->
     <Compile Include="..\Xamarin.Android.Build.Tasks\Linker\External\Linker\BaseMarkHandler.cs" Link="External\BaseMarkHandler.cs" />
-    <Compile Include="..\Xamarin.Android.Build.Tasks\Linker\MonoDroid.Tuner\AddKeepAlivesStep.cs" Link="MonoDroid.Tuner\AddKeepAlivesStep.cs" />
     <Compile Include="..\Xamarin.Android.Build.Tasks\Linker\MonoDroid.Tuner\AndroidLinkConfiguration.cs" Link="MonoDroid.Tuner\AndroidLinkConfiguration.cs" />
     <Compile Include="..\Xamarin.Android.Build.Tasks\Linker\MonoDroid.Tuner\Extensions.cs" Link="MonoDroid.Tuner\Extensions.cs" />
     <Compile Include="..\Xamarin.Android.Build.Tasks\Linker\MonoDroid.Tuner\FixAbstractMethodsStep.cs" Link="MonoDroid.Tuner\FixAbstractMethodsStep.cs" />

src/Xamarin.Android.Build.Tasks/Linker/MonoDroid.Tuner/AddKeepAlivesHelper.cs

@@ -0,0 +1,125 @@
+using System;
+using System.Linq;
+using Java.Interop.Tools.Cecil;
+using Mono.Cecil;
+using Mono.Cecil.Cil;
+using Xamarin.Android.Tasks;
+
+namespace MonoDroid.Tuner
+{
+	static class AddKeepAlivesHelper
+	{
+		internal static bool AddKeepAlives (AssemblyDefinition assembly, IMetadataResolver resolver, Func<AssemblyDefinition> getCorlibAssembly, Action<string> logMessage)
+		{
+			if (!assembly.MainModule.HasTypeReference ("Java.Lang.Object"))
+				return false;
+
+			// Anything that was built against .NET for Android will have
+			// keep-alives already compiled in.
+			if (MonoAndroidHelper.IsDotNetAndroidAssembly (assembly))
+				return false;
+
+			MethodDefinition? methodKeepAlive = null;
+			bool changed = false;
+			foreach (TypeDefinition type in assembly.MainModule.Types)
+				changed |= ProcessType (type, resolver, ref methodKeepAlive, getCorlibAssembly, logMessage);
+
+			return changed;
+		}
+
+		static bool ProcessType (TypeDefinition type, IMetadataResolver resolver, ref MethodDefinition? methodKeepAlive, Func<AssemblyDefinition> getCorlibAssembly, Action<string> logMessage)
+		{
+  			bool changed = false;
+			if (MightNeedFix (type, resolver))
+				changed |= AddKeepAlives (type, ref methodKeepAlive, getCorlibAssembly, logMessage);
+
+			if (type.HasNestedTypes) {
+				foreach (var t in type.NestedTypes) {
+					changed |= ProcessType (t, resolver, ref methodKeepAlive, getCorlibAssembly, logMessage);
+				}
+			}
+
+			return changed;
+		}
+
+		static bool MightNeedFix (TypeDefinition type, IMetadataResolver resolver)
+		{
+			return !type.IsAbstract && type.IsSubclassOf ("Java.Lang.Object", resolver);
+		}
+
+		static bool AddKeepAlives (TypeDefinition type, ref MethodDefinition? methodKeepAlive, Func<AssemblyDefinition> getCorlibAssembly, Action<string> logMessage)
+		{
+			bool changed = false;
+			foreach (MethodDefinition method in type.Methods) {
+				if (method.Parameters.Count == 0)
+					continue;
+
+				if (!method.CustomAttributes.Any (a => a.AttributeType.FullName == "Android.Runtime.RegisterAttribute"))
+					continue;
+
+				var instructions = method.Body.Instructions;
+
+				var found = false;
+				for (int off = Math.Max (0, instructions.Count - 6); off < instructions.Count; off++) {
+					var current = instructions [off];
+					if (current.OpCode == OpCodes.Call && current.Operand.ToString ().Contains ("System.GC::KeepAlive")) {
+						found = true;
+						break;
+					}
+				}
+
+				if (found)
+					continue;
+
+				var processor = method.Body.GetILProcessor ();
+				var module = method.DeclaringType.Module;
+				var end = instructions.Last ();
+				if (end.Previous.OpCode == OpCodes.Endfinally)
+					end = end.Previous;
+
+				for (int i = 0; i < method.Parameters.Count; i++) {
+					if (method.Parameters [i].ParameterType.IsValueType || method.Parameters [i].ParameterType.FullName == "System.String")
+						continue;
+
+					if (methodKeepAlive == null)
+						methodKeepAlive = GetKeepAliveMethod (getCorlibAssembly, logMessage);
+
+					if (methodKeepAlive == null) {
+						logMessage ("Unable to add KeepAlive call, did not find System.GC.KeepAlive method.");
+						break;
+					}
+
+					processor.InsertBefore (end, GetLoadArgumentInstruction (method.IsStatic ? i : i + 1, method.Parameters [i]));
+					processor.InsertBefore (end, Instruction.Create (OpCodes.Call, module.ImportReference (methodKeepAlive)));
+					changed = true;
+				}
+			}
+			return changed;
+		}
+
+		static MethodDefinition? GetKeepAliveMethod (Func<AssemblyDefinition> getCorlibAssembly, Action<string> logMessage)
+		{
+			var corlibAssembly = getCorlibAssembly ();
+			if (corlibAssembly == null)
+				return null;
+
+			var gcType = Extensions.GetType (corlibAssembly, "System.GC");
+			if (gcType == null)
+				return null;
+
+			return Extensions.GetMethod (gcType, "KeepAlive", new string [] { "System.Object" });
+		}
+
+		// Adapted from src/Mono.Android.Export/Mono.CodeGeneration/CodeArgumentReference.cs
+		static Instruction GetLoadArgumentInstruction (int argNum, ParameterDefinition parameter)
+		{
+			switch (argNum) {
+				case 0: return Instruction.Create (OpCodes.Ldarg_0);
+				case 1: return Instruction.Create (OpCodes.Ldarg_1);
+				case 2: return Instruction.Create (OpCodes.Ldarg_2);
+				case 3: return Instruction.Create (OpCodes.Ldarg_3);
+				default: return Instruction.Create (OpCodes.Ldarg, parameter);
+			}
+		}
+	}
+}

src/Xamarin.Android.Build.Tasks/Linker/MonoDroid.Tuner/AddKeepAlivesStep.cs

@@ -1,169 +1,23 @@
-using System;
-using System.Linq;
-using Java.Interop.Tools.Cecil;
 using Mono.Cecil;
-using Mono.Cecil.Cil;
-using Mono.Linker;
 using Mono.Linker.Steps;
 using Xamarin.Android.Tasks;
 
 namespace MonoDroid.Tuner
 {
-	public class AddKeepAlivesStep : BaseStep
-#if !ILLINK
-		, IAssemblyModifierPipelineStep
-#endif  // !ILLINK
+	public class AddKeepAlivesStep : BaseStep, IAssemblyModifierPipelineStep
 	{
 
-		protected override void ProcessAssembly (AssemblyDefinition assembly)
-		{
-			var action = Annotations.HasAction (assembly) ? Annotations.GetAction (assembly) : AssemblyAction.Skip;
-			if (action == AssemblyAction.Delete)
-				return;
-
-			if (AddKeepAlives (assembly)) {
-				if (action == AssemblyAction.Skip || action == AssemblyAction.Copy)
-					Annotations.SetAction (assembly, AssemblyAction.Save);
-			}
-		}
-
-#if !ILLINK
 		public void ProcessAssembly (AssemblyDefinition assembly, StepContext context)
 		{
 			// Only run this step on user Android assemblies
 			if (!context.IsAndroidUserAssembly)
 				return;
 
-			context.IsAssemblyModified |= AddKeepAlives (assembly);
-		}
-#endif  // !ILLINK
-
-		internal bool AddKeepAlives (AssemblyDefinition assembly)
-		{
-			if (!assembly.MainModule.HasTypeReference ("Java.Lang.Object"))
-				return false;
-
-			// Anything that was built against .NET for Android will have
-			// keep-alives already compiled in.
-			if (MonoAndroidHelper.IsDotNetAndroidAssembly (assembly))
-				return false;
-
-			bool changed = false;
-			foreach (TypeDefinition type in assembly.MainModule.Types)
-				changed |= ProcessType (type);
-
-			return changed;
-		}
-
-		bool ProcessType (TypeDefinition type)
-		{
-  			bool changed = false;
-			if (MightNeedFix (type))
-				changed |= AddKeepAlives (type);
-
-			if (type.HasNestedTypes) {
-				foreach (var t in type.NestedTypes) {
-					changed |= ProcessType (t);
-				}
-			}
-
-			return changed;
-		}
-
-		bool MightNeedFix (TypeDefinition type)
-		{
-			return !type.IsAbstract && type.IsSubclassOf ("Java.Lang.Object", Context);
-		}
-
-		MethodDefinition? methodKeepAlive = null;
-
-		bool AddKeepAlives (TypeDefinition type)
-		{
-			bool changed = false;
-			foreach (MethodDefinition method in type.Methods) {
-				if (method.Parameters.Count == 0)
-					continue;
-
-				if (!method.CustomAttributes.Any (a => a.AttributeType.FullName == "Android.Runtime.RegisterAttribute"))
-					continue;
-
-				var instructions = method.Body.Instructions;
-
-				var found = false;
-				for (int off = Math.Max (0, instructions.Count - 6); off < instructions.Count; off++) {
-					var current = instructions [off];
-					if (current.OpCode == OpCodes.Call && current.Operand.ToString ().Contains ("System.GC::KeepAlive")) {
-						found = true;
-						break;
-					}
-				}
-
-				if (found)
-					continue;
-
-				var processor = method.Body.GetILProcessor ();
-				var module = method.DeclaringType.Module;
-				var end = instructions.Last ();
-				if (end.Previous.OpCode == OpCodes.Endfinally)
-					end = end.Previous;
-
-				for (int i = 0; i < method.Parameters.Count; i++) {
-					if (method.Parameters [i].ParameterType.IsValueType || method.Parameters [i].ParameterType.FullName == "System.String")
-						continue;
-
-					if (methodKeepAlive == null)
-						methodKeepAlive = GetKeepAliveMethod ();
-
-					if (methodKeepAlive == null) {
-						LogMessage ("Unable to add KeepAlive call, did not find System.GC.KeepAlive method.");
-						break;
-					}
-
-					processor.InsertBefore (end, GetLoadArgumentInstruction (method.IsStatic ? i : i + 1, method.Parameters [i]));
-					processor.InsertBefore (end, Instruction.Create (OpCodes.Call, module.ImportReference (methodKeepAlive)));
-					changed = true;
-				}
-			}
-			return changed;
-		}
-
-		protected virtual AssemblyDefinition GetCorlibAssembly ()
-		{
-			return Context.GetAssembly ("System.Private.CoreLib");
-		}
-
-		MethodDefinition? GetKeepAliveMethod ()
-		{
-			var corlibAssembly = GetCorlibAssembly ();
-			if (corlibAssembly == null)
-				return null;
-
-			var gcType = Extensions.GetType (corlibAssembly, "System.GC");
-			if (gcType == null)
-				return null;
-
-			return Extensions.GetMethod (gcType, "KeepAlive", new string [] { "System.Object" });
-		}
-
-		public
-#if !ILLINK
-		override
-#endif
-		void LogMessage (string message)
-		{
-			Context.LogMessage (message);
-		}
-
-		// Adapted from src/Mono.Android.Export/Mono.CodeGeneration/CodeArgumentReference.cs
-		static Instruction GetLoadArgumentInstruction (int argNum, ParameterDefinition parameter)
-		{
-			switch (argNum) {
-				case 0: return Instruction.Create (OpCodes.Ldarg_0);
-				case 1: return Instruction.Create (OpCodes.Ldarg_1);
-				case 2: return Instruction.Create (OpCodes.Ldarg_2);
-				case 3: return Instruction.Create (OpCodes.Ldarg_3);
-				default: return Instruction.Create (OpCodes.Ldarg, parameter);
-			}
+			context.IsAssemblyModified |= AddKeepAlivesHelper.AddKeepAlives (
+				assembly,
+				Context,
+				() => Context.GetAssembly ("System.Private.CoreLib"),
+				(msg) => LogMessage (msg));
 		}
 	}
 }

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

@@ -8,6 +8,7 @@
   <UsingTask TaskName="Xamarin.Android.Tasks.RemoveRegisterAttribute" AssemblyFile="$(_XamarinAndroidBuildTasksAssembly)" />
   <UsingTask TaskName="Xamarin.Android.Tasks.GenerateProguardConfiguration" AssemblyFile="$(_XamarinAndroidBuildTasksAssembly)" />
   <UsingTask TaskName="Xamarin.Android.Tasks.StripEmbeddedLibraries" AssemblyFile="$(_XamarinAndroidBuildTasksAssembly)" />
+  <UsingTask TaskName="Xamarin.Android.Tasks.AddKeepAlives" AssemblyFile="$(_XamarinAndroidBuildTasksAssembly)" />
 
   <PropertyGroup>
     <_RemoveRegisterFlag>$(MonoAndroidIntermediateAssemblyDir)shrunk\shrunk.flag</_RemoveRegisterFlag>
@@ -197,12 +198,6 @@
       <_TrimmerCustomSteps Include="$(_AndroidLinkerCustomStepAssembly)" Type="Microsoft.Android.Sdk.ILLink.PreserveJavaInterfaces" />
       <_TrimmerCustomSteps Include="$(_AndroidLinkerCustomStepAssembly)" Type="MonoDroid.Tuner.FixAbstractMethodsStep" />
       <!-- Custom steps that run after MarkStep -->
-      <_TrimmerCustomSteps
-          Condition=" '$(AndroidAddKeepAlives)' == 'true' "
-          Include="$(_AndroidLinkerCustomStepAssembly)"
-          AfterStep="CleanStep"
-          Type="MonoDroid.Tuner.AddKeepAlivesStep"
-      />
       <!-- Custom steps that run after CleanStep -->
       <_TrimmerCustomSteps
           Condition=" '$(AndroidLinkResources)' == 'true' "
@@ -266,6 +261,22 @@
         Deterministic="$(Deterministic)" />
   </Target>
 
+  <!--
+    Inject GC.KeepAlive() calls into binding methods of trimmed assemblies.
+    Runs in the inner build after ILLink but before ReadyToRun/crossgen2 compilation,
+    so R2R images are generated from the already-modified assemblies.
+  -->
+  <Target Name="_AddKeepAlives"
+      AfterTargets="ILLink"
+      Condition=" '$(PublishTrimmed)' == 'true' and '$(AndroidAddKeepAlives)' == 'true' ">
+    <ItemGroup>
+      <_AddKeepAlivesAssembly Include="@(ResolvedFileToPublish)" Condition=" '%(Extension)' == '.dll' " />
+    </ItemGroup>
+    <AddKeepAlives
+        Assemblies="@(_AddKeepAlivesAssembly)"
+        Deterministic="$(Deterministic)" />
+  </Target>
+
   <!-- Inject _TypeMapKind into the property cache -->
   <Target Name="_SetTypemapProperties"
       BeforeTargets="_CreatePropertiesCache">