[dotnet] Test integration (#18543)

Fixed an issue where the C# class name was coming in with `,
AssemblyName` tacked on the end.
Fixed an issue where a class that had an entry in the map didn't have a
`class_ptr` which was causing an NRE.
Fixed a predicate for deciding when to mark the assembly for save.

Note - for an as yet undetermined reason, the linker is not picking up
that I'm marking the assembly for save, which is why the `true` test
cases are commented out.
This fixes issue 16671 #16671

dotnet/targets/Xamarin.Shared.Sdk.targets

@@ -687,6 +687,7 @@
 			<!-- The ListExportedSymbols must run after ExtractBindingLibrariesStep, otherwise we won't properly list exported Objective-C classes from binding libraries -->
 			<_TrimmerCustomSteps Include="$(_AdditionalTaskAssembly)" BeforeStep="OutputStep" Type="Xamarin.Linker.Steps.ListExportedSymbols" />
 			<_TrimmerCustomSteps Include="$(_AdditionalTaskAssembly)" BeforeStep="OutputStep" Type="Xamarin.Linker.Steps.PreOutputDispatcher" />
+			<_TrimmerCustomSteps Include="$(_AdditionalTaskAssembly)" BeforeStep="OutputStep" Type="Xamarin.Linker.ClassHandleRewriterStep" />
 
 			<!--
 				post-output steps

runtime/xamarin/runtime.h

@@ -129,6 +129,7 @@ struct MTRegistrationMap {
 	int skipped_map_count;
 	int protocol_wrapper_count;
 	int protocol_count;
+	void **classHandles;
 };
 
 typedef struct {

src/ObjCRuntime/Registrar.cs

@@ -134,6 +134,7 @@ internal class ObjCType {
 			public IntPtr Handle;
 #else
 			public TType ProtocolWrapperType;
+			public int ClassMapIndex;
 #endif
 
 			public Dictionary<string, ObjCField> Fields;

src/ObjCRuntime/Runtime.cs

@@ -74,6 +74,7 @@ internal unsafe struct MTRegistrationMap {
 			public int skipped_map_count;
 			public int protocol_wrapper_count;
 			public int protocol_count;
+			public IntPtr* classHandles;
 		}
 #pragma warning restore 649
 
@@ -210,8 +211,29 @@ public bool IsSimulator {
 #if NET
 		public static class ClassHandles
 		{
-			internal static unsafe void InitializeClassHandles (MTClassMap* map)
+			static NativeHandle unused;
+			internal static unsafe void InitializeClassHandles (IntPtr* map)
 			{
+				// This code is necessary. What happens is that
+				// in the case of class handle rewriting, any
+				// IL generated by this gets deleted, but the
+				// variables created are left behind and
+				// Rewriter uses those.
+				// In the case of NO class handle rewriting,
+				// this is a no-op
+				fixed (NativeHandle *ptr = &unused) {
+					SetHandle (-1, ptr, map);
+				}
+			}
+
+			[Preserve]
+			internal static unsafe void SetHandle (int index, NativeHandle* handle, IntPtr* map)
+			{
+				if (index < 0)
+					return;
+
+				var nativeHandle = map [index];
+				*handle = (NativeHandle)nativeHandle;
 			}
 		}
 #endif
@@ -327,8 +349,8 @@ unsafe static void Initialize (InitializationOptions* options)
 			}
 
 #if NET
-			if (options->RegistrationMap is not null && options->RegistrationMap->map is not null) {
-				ClassHandles.InitializeClassHandles (options->RegistrationMap->map);
+			if (options->RegistrationMap is not null && options->RegistrationMap->classHandles is not null) {
+				ClassHandles.InitializeClassHandles (options->RegistrationMap->classHandles);
 			}
 #endif
 

tests/dotnet/MyClassRedirectApp/AppDelegate.cs

@@ -0,0 +1,25 @@
+using System;
+using System.Runtime.InteropServices;
+using Foundation;
+using ObjCRuntime;
+
+namespace MySimpleApp {
+	public class Program {
+		static int Main (string [] args)
+		{
+			var someObj = new SomeObj ();
+			var handle = someObj.ClassHandle;
+			return handle == NativeHandle.Zero ? 1 : 0;
+		}
+	}
+
+	public class SomeObj : NSObject {
+		static NativeHandle class_ptr = Class.GetHandle (typeof (SomeObj));
+		[Export ("whatever")]
+		public IntPtr Whatever ()
+		{
+			return new IntPtr (0xdeadf00d);
+		}
+		public override NativeHandle ClassHandle => class_ptr;
+	}
+}

tests/dotnet/MyClassRedirectApp/MacCatalyst/Makefile

@@ -0,0 +1 @@
+include ../shared.mk

tests/dotnet/MyClassRedirectApp/MacCatalyst/MyClassRedirectApp.csproj

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project Sdk="Microsoft.NET.Sdk">
+	<PropertyGroup>
+		<TargetFramework>net$(BundledNETCoreAppTargetFrameworkVersion)-maccatalyst</TargetFramework>
+	</PropertyGroup>
+	<Import Project="..\shared.csproj" />
+</Project>

tests/dotnet/MyClassRedirectApp/Makefile

@@ -0,0 +1,2 @@
+TOP=../../..
+include $(TOP)/tests/common/shared-dotnet-test.mk

tests/dotnet/MyClassRedirectApp/iOS/Makefile

@@ -0,0 +1 @@
+include ../shared.mk

tests/dotnet/MyClassRedirectApp/iOS/MyClassRedirectApp.csproj

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project Sdk="Microsoft.NET.Sdk">
+	<PropertyGroup>
+		<TargetFramework>net$(BundledNETCoreAppTargetFrameworkVersion)-ios</TargetFramework>
+	</PropertyGroup>
+	<Import Project="..\shared.csproj" />
+</Project>

tests/dotnet/MyClassRedirectApp/macOS/Makefile

@@ -0,0 +1 @@
+include ../shared.mk

tests/dotnet/MyClassRedirectApp/macOS/MyClassRedirectApp.csproj

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project Sdk="Microsoft.NET.Sdk">
+	<PropertyGroup>
+		<TargetFramework>net$(BundledNETCoreAppTargetFrameworkVersion)-macos</TargetFramework>
+	</PropertyGroup>
+	<Import Project="..\shared.csproj" />
+</Project>

tests/dotnet/MyClassRedirectApp/shared.csproj

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project>
+	<PropertyGroup>
+		<OutputType>Exe</OutputType>
+
+		<ApplicationTitle>MyClassRedirectApp</ApplicationTitle>
+		<ApplicationId>com.xamarin.myclassredirectapp</ApplicationId>
+
+		<ExcludeNUnitLiteReference>true</ExcludeNUnitLiteReference>
+		<ExcludeTouchUnitReference>true</ExcludeTouchUnitReference>
+
+		<DefineConstants>$(DefineConstants);$(AdditionalDefineConstants)</DefineConstants>
+	</PropertyGroup>
+
+	<Import Project="../../common/shared-dotnet.csproj" />
+
+	<ItemGroup>
+		<Compile Include="../*.cs" />
+	</ItemGroup>
+</Project>

tests/dotnet/MyClassRedirectApp/shared.mk

@@ -0,0 +1,3 @@
+TOP=../../../..
+TESTNAME=MyClassRedirectApp
+include $(TOP)/tests/common/shared-dotnet.mk

tests/dotnet/MyClassRedirectApp/tvOS/Makefile

@@ -0,0 +1 @@
+include ../shared.mk

tests/dotnet/MyClassRedirectApp/tvOS/MyClassRedirectApp.csproj

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFramework>net$(BundledNETCoreAppTargetFrameworkVersion)-tvos</TargetFramework>
+  </PropertyGroup>
+  <Import Project="..\shared.csproj" />
+</Project>

tests/dotnet/UnitTests/RegistrarTest.cs

@@ -1,3 +1,5 @@
+using Mono.Cecil;
+
 namespace Xamarin.Tests {
 	[TestFixture]
 	public class RegistrarTest : TestBaseClass {
@@ -25,7 +27,6 @@ public void InvalidStaticRegistrarValidation (ApplePlatform platform, bool valid
 
 			var appDir = GetAppPath (projectPath, platform, runtimeIdentifiers, configuration);
 			var asmDir = Path.Combine (appDir, GetRelativeAssemblyDirectory (platform));
-
 			var appExecutable = Path.Combine (asmDir, project + ".dll");
 
 			// Save the first version of the main assembly in memory
@@ -50,6 +51,80 @@ public void InvalidStaticRegistrarValidation (ApplePlatform platform, bool valid
 				Environment.SetEnvironmentVariable ("XAMARIN_VALIDATE_STATIC_REGISTRAR_CODE", null);
 			}
 		}
+
+#if NET
+		[TestCase (ApplePlatform.MacCatalyst, false)]
+		[TestCase (ApplePlatform.MacOSX, false)]
+		[TestCase (ApplePlatform.iOS, false)]
+		[TestCase (ApplePlatform.TVOS, false)]
+		[TestCase (ApplePlatform.MacCatalyst, true)]
+		[TestCase (ApplePlatform.iOS, true)]
+		[TestCase (ApplePlatform.TVOS, true)]
+		public void ClassRewriterTest (ApplePlatform platform, bool rewriteHandles)
+		{
+			var project = "MyClassRedirectApp";
+			var configuration = "Debug";
+			var runtimeIdentifiers = GetDefaultRuntimeIdentifier (platform);
+			Configuration.IgnoreIfIgnoredPlatform (platform);
+
+			var projectPath = GetProjectPath (project, platform: platform);
+			Clean (projectPath);
+			var properties = GetDefaultProperties ();
+			properties ["Registrar"] = "static";
+			// enable the linker (so that the main assembly is modified)
+			properties ["LinkMode"] = "full";
+			properties ["MtouchLink"] = "full";
+			if (rewriteHandles)
+				properties ["MtouchExtraArgs"] = "--optimize=redirect-class-handles";
+
+			DotNet.AssertBuild (projectPath, properties);
+
+			var appDir = GetAppPath (projectPath, platform, runtimeIdentifiers, configuration);
+			var asmDir = Path.Combine (appDir, GetRelativeAssemblyDirectory (platform));
+
+			var appExecutable = Path.Combine (asmDir, project + ".dll");
+			var platformDll = Path.Combine (asmDir, Configuration.GetBaseLibraryName (platform, true));
+			Assert.That (File.Exists (platformDll), "No platform dll.");
+			var module = ModuleDefinition.ReadModule (platformDll);
+			var classHandlesMaybe = AllTypes (module).FirstOrDefault (t => t.FullName == "ObjCRuntime.Runtime/ClassHandles");
+			Assert.NotNull (classHandlesMaybe, "Couldn't find ClassHandles type.");
+			var classHandles = classHandlesMaybe!;
+			if (!rewriteHandles) {
+				// NB: there is always at least one field named "unused"
+				var fields = classHandles.Fields.Where (f => f.Name != "unused").Select (f => f.Name).ToList ();
+				var sb = new StringBuilder ();
+				foreach (var f in fields) {
+					sb.Append (" ").Append (f);
+				}
+				Assert.That (fields.Count == 0, "There are fields in classHandles - rewriter was called when it should have done nothing." + sb);
+			} else {
+				// NB: there is always at least one field named "unused"
+				Assert.That (classHandles.HasFields && classHandles.Fields.Count () > 1, "There are no fields in ClassHandles - rewriter did nothing.");
+				var field = classHandles.Fields.FirstOrDefault (f => f.Name.Contains ("SomeObj"));
+				Assert.IsNotNull (field, "Didn't find a field for 'SomeObj'");
+			}
+		}
+
+		IEnumerable<TypeDefinition> AllTypes (ModuleDefinition module)
+		{
+			foreach (var type in module.Types) {
+				yield return type;
+				foreach (var t in InnerTypes (type))
+					yield return t;
+			}
+		}
+
+		IEnumerable<TypeDefinition> InnerTypes (TypeDefinition type)
+		{
+			if (type.HasNestedTypes) {
+				foreach (var t in type.NestedTypes) {
+					yield return t;
+					foreach (var nt in InnerTypes (t))
+						yield return nt;
+				}
+			}
+		}
+#endif
 	}
 }