[illink] Remove custom types marking for types which XA does not own …

…for netcore (#5354)

This is or will be handled by BCL libraries and XA tooling should try
not to interfere with more fine tuned handling done by BCL.

Simplifies `[Preserve]` attribute implementation and removes
old code to preserve serialization, which doesn't work
well with new .NET5/6 runtime libraries. (the old serialization
code: https://github.com/xamarin/xamarin-android/blob/master/src/Xamarin.Android.Build.Tasks/Linker/MonoDroid.Tuner/ApplyPreserveAttribute.cs#L57-L82)

The serialization is currently [broken](dotnet/runtime#45559)
and will be fixed in runtime libs. Part of `CustomLinkDescriptionPreserve`
test is thus disabled.

Also the attribute removal is now handled in illink.

The serialization fix leads to great reduction of assemblies size in simple
XA test app by cca 1MB, apkdiff before/after:

    Summary:
      -   1,199,411 Assemblies -55.66% (of 2,154,984)
      -   1,206,333 Package size difference -13.37% (of 9,024,291)

Co-authored-by: Radek Doulik <radekdoulik@gmail.com>

src/Microsoft.Android.Sdk.ILLink/ApplyPreserveAttributeBase.cs → src/Microsoft.Android.Sdk.ILLink/ApplyPreserveAttribute.cs

@@ -11,10 +11,7 @@
 namespace Microsoft.Android.Sdk.ILLink
 {
 
-	public abstract class ApplyPreserveAttributeBase : BaseSubStep {
-
-		// set 'removeAttribute' to true if you want the preserved attribute to be removed from the final assembly
-		protected abstract bool IsPreservedAttribute (ICustomAttributeProvider provider, CustomAttribute attribute, out bool removeAttribute);
+	public class ApplyPreserveAttribute : BaseSubStep {
 
 		public override SubStepTargets Targets {
 			get {
@@ -66,7 +63,7 @@ public override void ProcessEvent (EventDefinition @event)
 
 		void MarkMethodIfPreserved (MethodDefinition method)
 		{
-			foreach (var attribute in GetPreserveAttributes (method)) 
+			foreach (var attribute in GetPreserveAttributes (method))
 				MarkMethod (method, attribute);
 		}
 
@@ -126,6 +123,9 @@ void PreserveUnconditional (IMetadataTokenProvider provider)
 
 		void TryApplyPreserveAttribute (TypeDefinition type)
 		{
+			if (!type.HasCustomAttributes)
+				return;
+
 			foreach (var attribute in GetPreserveAttributes (type)) {
 				Annotations.Mark (type);
 
@@ -138,28 +138,9 @@ void TryApplyPreserveAttribute (TypeDefinition type)
 			}
 		}
 
-		List<CustomAttribute> GetPreserveAttributes (ICustomAttributeProvider provider)
+		static IEnumerable<CustomAttribute> GetPreserveAttributes (ICustomAttributeProvider provider)
 		{
-			List<CustomAttribute> attrs = new List<CustomAttribute> ();
-
-			if (!provider.HasCustomAttributes)
-				return attrs;
-
-			var attributes = provider.CustomAttributes;
-
-			for (int i = attributes.Count - 1; i >= 0; i--) {
-				var attribute = attributes [i];
-
-				bool remote_attribute;
-				if (!IsPreservedAttribute (provider, attribute, out remote_attribute))
-					continue;
-
-				attrs.Add (attribute);
-				if (remote_attribute)
-					attributes.RemoveAt (i);
-			}
-
-			return attrs;
+			return provider.CustomAttributes.Where (a => a.Constructor.DeclaringType.Name == "PreserveAttribute");
 		}
 	}
 }

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

@@ -28,6 +28,7 @@
     <Compile Remove="..\Xamarin.Android.Build.Tasks\Linker\MonoDroid.Tuner\LinkerOptions.cs" />
 
     <!--Steps that are upstreamed, these are OK to remove-->
+    <Compile Remove="..\Xamarin.Android.Build.Tasks\Linker\MonoDroid.Tuner\ApplyPreserveAttribute.cs" />
     <Compile Remove="..\Xamarin.Android.Build.Tasks\Linker\MonoDroid.Tuner\OutputStepWithTimestamps.cs" />
     <Compile Remove="..\Xamarin.Android.Build.Tasks\Linker\MonoDroid.Tuner\PreserveCode.cs" />
     <Compile Remove="..\Xamarin.Android.Build.Tasks\Linker\MonoDroid.Tuner\PreserveDynamicTypes.cs" />
@@ -36,6 +37,7 @@
     <Compile Remove="..\Xamarin.Android.Build.Tasks\Linker\MonoDroid.Tuner\PreserveRuntimeSerialization.cs" />
     <Compile Remove="..\Xamarin.Android.Build.Tasks\Linker\MonoDroid.Tuner\PreserveTlsProvider.cs" />
     <Compile Remove="..\Xamarin.Android.Build.Tasks\Linker\MonoDroid.Tuner\PreserveTypeConverters.cs" />
+    <Compile Remove="..\Xamarin.Android.Build.Tasks\Linker\MonoDroid.Tuner\RemoveAttributes.cs" />
 
     <!--TODO: Subclasses MarkStep-->
     <Compile Remove="..\Xamarin.Android.Build.Tasks\Linker\MonoDroid.Tuner\MonoDroidMarkStep.cs" />

src/Microsoft.Android.Sdk.ILLink/SetupStep.cs

@@ -43,7 +43,6 @@ protected override void Process ()
 			subSteps2.Add (new PreserveApplications ());
 			subSteps2.Add (new PreserveRegistrations (cache));
 			subSteps2.Add (new PreserveJavaInterfaces ());
-			subSteps2.Add (new RemoveAttributes ());
 
 			InsertAfter (new FixAbstractMethodsStep (cache), "RemoveUnreachableBlocksStep");
 			InsertAfter (subSteps2, "RemoveUnreachableBlocksStep");

src/Mono.Android/ILLink/ILLink.LinkAttributes.xml

@@ -0,0 +1,10 @@
+<linker>
+  <assembly fullname="Mono.Android">
+    <type fullname="Android.Runtime.PreserveAttribute">
+      <attribute internal="RemoveAttributeInstances" />
+    </type>
+    <type fullname="Android.Runtime.IntDefinitionAttribute">
+      <attribute internal="RemoveAttributeInstances" />
+    </type>
+  </assembly>
+</linker>

src/Mono.Android/Mono.Android.csproj

@@ -85,6 +85,8 @@
 
   <ItemGroup Condition=" '$(TargetFramework)' == 'netcoreapp3.1' ">
     <ProjectReference Include="..\..\external\Java.Interop\src\Java.Interop\Java.Interop.csproj" />
+
+    <EmbeddedResource Include="ILLink/ILLink.LinkAttributes.xml" />
   </ItemGroup>
 
   <ItemGroup>

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/PackagingTest.cs

@@ -85,38 +85,14 @@ public void CheckIncludedAssemblies ()
 			var expectedFiles = Builder.UseDotNet ?
 				new [] {
 					"Java.Interop.dll",
-					"Microsoft.Win32.Primitives.dll",
 					"Mono.Android.dll",
-					"System.Collections.NonGeneric.dll",
 					"System.ComponentModel.Primitives.dll",
 					"System.Console.dll",
-					"System.Formats.Asn1.dll",
-					"System.IO.Compression.Brotli.dll",
-					"System.IO.Compression.dll",
-					"System.IO.FileSystem.dll",
 					"System.Linq.Expressions.dll",
-					"System.Net.Http.dll",
-					"System.Net.NameResolution.dll",
-					"System.Net.NetworkInformation.dll",
 					"System.Net.Primitives.dll",
-					"System.Net.Quic.dll",
-					"System.Net.Security.dll",
-					"System.Net.Sockets.dll",
 					"System.ObjectModel.dll",
-					"System.Private.Uri.dll",
-					"System.Private.Xml.dll",
-					"System.Private.Xml.Linq.dll",
-					"System.Runtime.CompilerServices.Unsafe.dll",
-					"System.Runtime.InteropServices.RuntimeInformation.dll",
-					"System.Runtime.Numerics.dll",
-					"System.Security.Cryptography.Encoding.dll",
-					"System.Security.Cryptography.OpenSsl.dll",
-					"System.Security.Cryptography.X509Certificates.dll",
 					"System.Runtime.Serialization.Primitives.dll",
-					"System.Security.Cryptography.Algorithms.dll",
 					"System.Security.Cryptography.Primitives.dll",
-					"System.Text.RegularExpressions.dll",
-					"System.Threading.Channels.dll",
 					"System.Private.CoreLib.dll",
 					"System.Collections.Concurrent.dll",
 					"System.Collections.dll",

tests/MSBuildDeviceIntegration/Resources/LinkDescTest/MainActivityReplacement.cs

@@ -117,8 +117,9 @@ protected override void OnCreate(Bundle bundle)
 			Android.Util.Log.Info(TAG, LinkTestLib.Bug21578.MulticastOption_ShouldNotBeStripped());
 			Android.Util.Log.Info(TAG, LinkTestLib.Bug21578.MulticastOption_ShouldNotBeStripped2());
 			Android.Util.Log.Info(TAG, LinkTestLib.Bug35195.AttemptCreateTable());
+#if !NET
 			Android.Util.Log.Info(TAG, LinkTestLib.Bug36250.SerializeSearchRequestWithDictionary());
-
+#endif
 			Android.Util.Log.Info(TAG, "All regression tests completed.");
 		}
 	}

tests/MSBuildDeviceIntegration/Tests/InstallAndRunTests.cs

@@ -330,12 +330,6 @@ public class LinkModeFullClass {
 								return sr.ReadToEnd ();
 						},
 					},
-					new BuildItem.Source ("Bug36250.cs") {
-						TextContent = () => {
-							using (var sr = new StreamReader (typeof (InstallAndRunTests).Assembly.GetManifestResourceStream ("Xamarin.Android.Build.Tests.Resources.LinkDescTest.Bug36250.cs")))
-								return sr.ReadToEnd ();
-						},
-					},
 					new BuildItem.Source ("Bug35195.cs") {
 						TextContent = () => {
 							using (var sr = new StreamReader (typeof (InstallAndRunTests).Assembly.GetManifestResourceStream ("Xamarin.Android.Build.Tests.Resources.LinkDescTest.Bug35195.cs")))
@@ -345,6 +339,17 @@ public class LinkModeFullClass {
 				},
 			};
 
+			if (!Builder.UseDotNet) {
+				// DataContractSerializer is not trimming safe
+				// https://github.com/dotnet/runtime/issues/45559
+				lib2.Sources.Add (new BuildItem.Source ("Bug36250.cs") {
+					TextContent = () => {
+						using (var sr = new StreamReader (typeof (InstallAndRunTests).Assembly.GetManifestResourceStream ("Xamarin.Android.Build.Tests.Resources.LinkDescTest.Bug36250.cs")))
+							return sr.ReadToEnd ();
+					},
+				});
+			}
+
 			proj = new XamarinFormsAndroidApplicationProject () {
 				IsRelease = true,
 				AndroidLinkModeRelease = linkMode,

tests/MSBuildDeviceIntegration/Tests/InstallTests.cs

@@ -217,7 +217,11 @@ public void InstallWithoutSharedRuntime ()
 				//	"The Shared Runtime should not have been installed.");
 				var directorylist = GetContentFromAllOverrideDirectories (proj.PackageName);
 				StringAssert.Contains ($"{proj.ProjectName}.dll", directorylist, $"{proj.ProjectName}.dll should exist in the .__override__ directory.");
-				StringAssert.Contains ($"System.dll", directorylist, $"System.dll should exist in the .__override__ directory.");
+				if (Builder.UseDotNet)
+					StringAssert.Contains ($"System.Private.CoreLib.dll", directorylist, $"System.Private.CoreLib.dll should exist in the .__override__ directory.");
+				else
+					StringAssert.Contains ($"System.dll", directorylist, $"System.dll should exist in the .__override__ directory.");
+
 				StringAssert.Contains ($"Mono.Android.dll", directorylist, $"Mono.Android.dll should exist in the .__override__ directory.");
 				Assert.IsTrue (builder.Uninstall (proj), "unnstall should have succeeded.");
 			}