[nnyeah] Fix for handling nfloat (#15021)

nfloat needed a proper reference to System.Runtime.InteropServices.

tools/nnyeah/nnyeah/ModuleExtensions.cs

@@ -4,23 +4,46 @@ using System.Collections.Generic;
 
 namespace Microsoft.MaciOS.Nnyeah {
 	public static class ModuleExtensions {
-		static Dictionary<string, PlatformName> moduleToPlatform = new Dictionary<string, PlatformName> {
+		static Dictionary<string, PlatformName> xamarinModuleToPlatform = new Dictionary<string, PlatformName> {
 			{ "Xamarin.iOS", PlatformName.iOS },
 			{ "Xamarin.Mac", PlatformName.macOS },
 			{ "Xamarin.TVOS", PlatformName.tvOS },
 			{ "Xamarin.WatchOS", PlatformName.watchOS }
 		};
 
+		static Dictionary<string, PlatformName> microsoftModuleToPlatform = new Dictionary<string, PlatformName> {
+			{ "Microsoft.iOS", PlatformName.iOS },
+			{ "Microsoft.macOS", PlatformName.macOS },
+			{ "Microsoft.tvOS", PlatformName.tvOS },
+			{ "Microsoft.watchOS", PlatformName.watchOS }
+		};
+
 		public static bool DependsOnXamarin (this ModuleDefinition module)
 		{
 			return module.XamarinPlatformName () != PlatformName.None;
 		}
 
 		public static PlatformName XamarinPlatformName (this ModuleDefinition module)
+		{
+			return FindPlatformName (module, xamarinModuleToPlatform);
+		}
+
+		public static bool DependsOnMicrosoft (this ModuleDefinition module)
+		{
+			return module.MicrosoftPlatformName () != PlatformName.None;
+		}
+
+		public static PlatformName MicrosoftPlatformName (this ModuleDefinition module)
+		{
+			return FindPlatformName (module, microsoftModuleToPlatform);
+		}
+
+		static PlatformName FindPlatformName (ModuleDefinition module, Dictionary<string, PlatformName> knownModules)
 		{
 			foreach (var possibleModule in module.AssemblyReferences) {
-				if (moduleToPlatform.TryGetValue (possibleModule.Name, out var platformName))
+				if (knownModules.TryGetValue (possibleModule.Name, out var platformName)) {
 					return platformName;
+				}
 			}
 			return PlatformName.None;
 		}

tools/nnyeah/nnyeah/Reworker.cs

@@ -27,6 +27,7 @@ namespace Microsoft.MaciOS.Nnyeah {
 		TypeReference NewNfloatTypeReference;
 		ModuleReference NewNfloatModuleReference;
 		TypeDefinition NewNativeHandleTypeDefinition;
+		AssemblyNameReference InteropServicesAssembly;
 
 		TypeAndMemberMap ModuleMap;
 
@@ -80,6 +81,11 @@ namespace Microsoft.MaciOS.Nnyeah {
 			NativeIntegerAttributeTypeRef = new TypeReference (NativeIntegerAttributeTypeDef.Namespace,
 				NativeIntegerAttributeTypeDef.Name, NativeIntegerAttributeTypeDef.Module, NativeIntegerAttributeTypeDef.Scope);
 
+			if (moduleMap.MicrosoftModule.AssemblyReferences.FirstOrDefault (an => an.Name == "System.Runtime.InteropServices") is AssemblyNameReference validReference) {
+				InteropServicesAssembly = validReference;
+			} else {
+				throw new NotSupportedException ($"Assembly {moduleMap.MicrosoftModule.Name} does not have reference to System.Runtime.InteropServices. This is not possible.");
+			}
 
 			// if these type references aren't found in the module
 			// then we don't ever need to worry about reworking them
@@ -92,10 +98,9 @@ namespace Microsoft.MaciOS.Nnyeah {
 			}
 			if (!module.TryGetTypeReference ("System.nfloat", out NfloatTypeReference)) {
 				NfloatTypeReference = EmptyTypeReference;
+			} else {
+				NewNfloatTypeReference = module.ImportReference (new TypeReference ("System.Runtime.InteropServices", "NFloat", null, InteropServicesAssembly, true));
 			}
-
-			NewNfloatModuleReference = new ModuleReference ("System.Private.CoreLib");
-			NewNfloatTypeReference = new TypeReference ("System.Runtime.InteropServices", "NFloat", null, NewNfloatModuleReference, true);
 			NewNativeHandleTypeDefinition = moduleMap.MicrosoftModule.Types.First (t => t.FullName == "ObjCRuntime.NativeHandle");
 
 			// These must be called last as they depend on Module and NativeIntegerAttributeTypeRef to be setup

tools/nnyeah/tests/DependencyRemovedTests.cs

@@ -12,8 +12,7 @@ namespace Microsoft.MaciOS.Nnyeah.Tests {
 	public class DependencyRemovedTests {
 		[TestCase ("nint")]
 		[TestCase ("nuint")]
-// nfloat has an issue on write.
-//		[TestCase ("nfloat")]
+		[TestCase ("nfloat")]
 		public async Task BasicDependencyRemoved (string type)
 		{
 			var dir = Cache.CreateTemporaryDirectory ($"DependencyRemoved_{type}");
@@ -37,7 +36,7 @@ public class Foo {{
 			var module = ModuleDefinition.ReadModule (targetRewrite);
 
 			var platform = module.XamarinPlatformName ();
-			Assert.AreEqual (Microsoft.MaciOS.Nnyeah.PlatformName.None, platform);
+			Assert.AreEqual (Microsoft.MaciOS.Nnyeah.PlatformName.None, platform, "still has Xamarin dependency");
 		}
 	}
 }