dotnet · rolfbjarne · May 20, 2025 · May 21, 2025 · May 22, 2025 · May 22, 2025
@@ -21,6 +21,7 @@
 // Copyright 2011-2014 Xamarin Inc.
 //
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 using System.Collections;
 using System.Runtime.InteropServices;
@@ -124,5 +125,18 @@ public NSTimer (NSDate date, TimeSpan when, Action<NSTimer> action, System.Boole
 			: this (date, when.TotalSeconds, new NSTimerActionDispatcher (action), NSTimerActionDispatcher.Selector, null, repeats)
 		{
 		}
+
+		// The dependency attribute is required because:
+		// * We inject a call to Invalidate in the generated Dispose method
+		// * We optimize Dispose methods to not touch fields that aren't otherwise used, which we do by
+		//   removing the contents of the Dispose method before the linker runs, then after the linker runs
+		//   we determine which fields the Dispose method touches have been linked away and remove any such code.
+		//   We won't remove the call to Invalidate, but the linker may have trimmed away the Invalidate method
+		///  itself (because we temporarly removed the call to it). So make sure the linker doesn't remove it.
+		[DynamicDependency ("Invalidate()")]
+		static NSTimer ()
+		{
+			GC.KeepAlive (null);
+		}
 	}
 }
diff --git a/src/bgen/Generator.cs b/src/bgen/Generator.cs
@@ -1597,11 +1597,6 @@ void GenerateTrampolinesForQueue (TrampolineInfo [] queue)
 			print ("//\n// This class bridges native block invocations that call into C#\n//");
 			PrintExperimentalAttribute (ti.Type);
 			print ("static internal class {0} {{", ti.StaticName); indent++;
-			// it can't be conditional without fixing https://github.com/mono/linker/issues/516
-			// but we have a workaround in place because we can't fix old, binary bindings so...
-			// print ("[Preserve (Conditional=true)]");
-			// For .NET we fix it using the DynamicDependency attribute below
-			print ("[Preserve (Conditional = true)]");
 			print ("[UnmanagedCallersOnly]");
 			print ("[UserDelegateType (typeof ({0}))]", ti.UserDelegate);
 			print ("internal static unsafe {0} Invoke ({1}) {{", ti.ReturnType, ti.Parameters);
@@ -1674,7 +1669,12 @@ void GenerateTrampolinesForQueue (TrampolineInfo [] queue)
 			print ("invoker = block->GetDelegateForBlock<{0}> ();", ti.DelegateName);
 			indent--; print ("}");
 			print ("");
-			print ("[Preserve (Conditional=true)]");
+			print ("[DynamicDependency (nameof (Create))]");
+			print ($"static {ti.NativeInvokerName} ()");
+			print ("{");
+			print ("\tGC.KeepAlive (null);"); // need to do _something_ (doesn't seem to matter what), otherwise the static cctor (and the DynamicDependency attributes) are trimmed away.
+			print ("}");
+			print ("");
 			print_generated_code ();
 			print ("public unsafe static {0}? Create (IntPtr block)\n{{", ti.UserDelegate); indent++;
 			print ("if (block == IntPtr.Zero)"); indent++;
@@ -1812,13 +1812,11 @@ void GenerateStrongDictionaryTypes ()
 				if (BindingTouch.SupportsXmlDocumentation) {
 					print ($"/// <summary>Creates a new <see cref=\"{typeName}\" /> with default (empty) values.</summary>");
 				}
-				print ("[Preserve (Conditional = true)]");
 				print ("public {0} () : base (new NSMutableDictionary ()) {{}}\n", typeName);
 				if (BindingTouch.SupportsXmlDocumentation) {
 					print ($"/// <summary>Creates a new <see cref=\"{typeName}\" /> from the values that are specified in <paramref name=\"dictionary\" />.</summary>");
 					print ($"/// <param name=\"dictionary\">The dictionary to use to populate the properties of this type.</param>");
 				}
-				print ("[Preserve (Conditional = true)]");
 				print ("public {0} (NSDictionary? dictionary) : base (dictionary) {{}}\n", typeName);

 				foreach (var pi in dictType.GatherProperties (this)) {
@@ -4986,6 +4984,7 @@ void GenerateProtocolTypes (Type type, string class_visibility, string TypeName,
 			}
 		}
 
+		var dynamicDependencies = new List<string> ();
 		if (instanceMethods.Any () || instanceProperties.Any ()) {
 			// Tell the trimmer to not remove any instance method/property if the interface itself isn't trimmed away.
 			// These members are required for the registrar to determine if a particular implementing method
@@ -4996,10 +4995,14 @@ void GenerateProtocolTypes (Type type, string class_visibility, string TypeName,
 			var docIds = instanceMethods
 				.Select (mi => DocumentationManager.GetDocId (mi, includeDeclaringType: false, alwaysIncludeParenthesis: true))
 				.Concat (instanceProperties.Select (v => v.Name))
-				.OrderBy (name => name);
-			foreach (var docId in docIds) {
-				print ($"[DynamicDependencyAttribute (\"{docId}\")]");
-			}
+				.Select (v => $"\"{v}\"");
+			dynamicDependencies.AddRange (docIds);
+		}
+		// Tell the trimmer to not remove the wrapper type if the interface itself isn't trimmed away
+		dynamicDependencies.Add ($"DynamicallyAccessedMemberTypes.Interfaces | DynamicallyAccessedMemberTypes.PublicConstructors, typeof ({TypeName}Wrapper)");
+		if (dynamicDependencies.Count > 0) {
+			foreach (var dd in dynamicDependencies.OrderBy (v => v))
+				print ($"[DynamicDependencyAttribute ({dd})]");
 			print ("[BindingImpl (BindingImplOptions.GeneratedCode | BindingImplOptions.Optimizable)]");
 			print ($"static I{TypeName} ()");
 			print ("{");
@@ -5112,7 +5115,6 @@ void GenerateProtocolTypes (Type type, string class_visibility, string TypeName,
 		indent++;
 		// ctor (IntPtr, bool)
 		PrintExperimentalAttribute (type);
-		print ("[Preserve (Conditional = true)]");
 		print ("public {0}Wrapper ({1} handle, bool owns)", TypeName, NativeHandleType);
 		print ("\t: base (handle, owns)");
 		print ("{");
@@ -5330,6 +5332,9 @@ public void PrintPreserveAttribute (ICustomAttributeProvider mi)
 		if (p is null)
 			return;
 
+		if (!BindThirdPartyLibrary)
+			throw new InvalidOperationException ($"Found [Preserve] on {FormatProvider (mi)}: [Preserve] is deprecated, so don't use it.");
+
 		if (p.AllMembers)
 			print ("[Preserve (AllMembers = true)]");
 		else if (p.Conditional)
@@ -6522,7 +6527,6 @@ public void Generate (Type type)
 						} else
 							print ("internal {0}? {1};", Nomenclator.GetDelegateName (mi), miname);
 
-						print ("[Preserve (Conditional = true)]");
 						if (isProtocolEventBacked)
 							print ("[Export (\"{0}\")]", FindSelector (dtype, mi));
 
@@ -6629,7 +6633,6 @@ public void Generate (Type type)
 							selRespondsToSelector = "selRespondsToSelector";
 						}
 
-						print ("[Preserve (Conditional = true)]");
 						print ("public override bool RespondsToSelector (Selector? sel)");
 						print ("{");
 						++indent;

@@ -7154,8 +7154,6 @@ interface NSTimer {
 		[Export ("fireDate", ArgumentSemantic.Copy)]
 		NSDate FireDate { get; set; }
 
-		// Note: preserving this member allows us to re-enable the `Optimizable` binding flag
-		[Preserve (Conditional = true)]
 		[Export ("invalidate")]
 		void Invalidate ();
 

diff --git a/tests/common/shared-dotnet.csproj b/tests/common/shared-dotnet.csproj
@@ -61,14 +61,6 @@
 		<CustomBeforeMicrosoftCommonTargets>$(CustomBeforeMicrosoftCommonTargets);$(MSBuildThisFileDirectory)SupportedOSPlatformVersions.targets</CustomBeforeMicrosoftCommonTargets>
 	</PropertyGroup>
 
-	<!-- Logic for NativeAOT -->
-	<PropertyGroup Condition="'$(PublishAot)' == 'true' And '$(_IsPublishing)' == 'true'">
-		<!-- Define NATIVEAOT when using NativeAOT -->
-		<DefineConstants>$(DefineConstants);NATIVEAOT</DefineConstants>
-		<!-- We're enabling warnaserror by default, but we're not warning-free for ILC (especially for NUnit), so disable warnaserror for ILC - https://github.com/dotnet/macios/issues/19911 -->
-		<IlcTreatWarningsAsErrors>false</IlcTreatWarningsAsErrors>
-	</PropertyGroup>
-
 	<!-- Trimmer options -->
 	<!-- We want to ignore any trimmer warnings from NUnit. We do this by:
 		* Enable all warnings
@@ -102,6 +94,14 @@
 
 	<Import Project="$(GeneratedProjectFile)" Condition="'$(GeneratedProjectFile)' != ''" />
 
+	<!-- Logic for NativeAOT -->
+	<PropertyGroup Condition="'$(PublishAot)' == 'true' And '$(_IsPublishing)' == 'true'">
+		<!-- Define NATIVEAOT when using NativeAOT -->
+		<DefineConstants>$(DefineConstants);NATIVEAOT</DefineConstants>
+		<!-- We're enabling warnaserror by default, but we're not warning-free for ILC (especially for NUnit), so disable warnaserror for ILC - https://github.com/dotnet/macios/issues/19911 -->
+		<IlcTreatWarningsAsErrors>false</IlcTreatWarningsAsErrors>
+	</PropertyGroup>
+
 	<!--
 		This is a helper target for our tests to zip up the app bundle.
 		This is useful when building remotely, and we want to inspect the results on Windows:

diff --git a/tests/common/shared-dotnet.mk b/tests/common/shared-dotnet.mk
@@ -208,7 +208,7 @@ diag: prepare
 		select binlog in $(BINLOGS); do $(DOTNET) build /v:diag $$binlog; break; done \
 	fi
 
-list-variations listvariations show-variations showvariations variations:
+list-variations listvariations show-variations showvariations variations help:
 	$(Q) if ! command -v jq > /dev/null; then echo "$(shell tput setaf 9)jq isn't installed. Install by doing 'brew install jq'$(shell tput sgr0)"; exit 1; fi
 	$(Q) echo "Test variations for $(shell tput setaf 6)$(TESTNAME)$(shell tput sgr0):"
 	$(Q) echo ""

diff --git a/tests/common/test-variations.csproj b/tests/common/test-variations.csproj
@@ -4,13 +4,31 @@
 	<ItemGroup>
 		<TestVariations Include="interpreter" Description="Run with the interpreter ('UseInterpreter=true')" />
 		<TestVariations Include="bundle-original-resources" Description="Bundle original resources ('BundleOriginalResources=true')" />
-		<TestVariations Include="do-not-bundle-original-resources" Description="Do not original resources ('BundleOriginalResources=false')" />
+		<TestVariations Include="do-not-bundle-original-resources" Description="Do not bundle original resources ('BundleOriginalResources=false')" />
+		<TestVariations Include="nativeaot" Description="Run with NativeAOT" />
+		<TestVariations Include="linksdk" Description="Run with trimmer (MtouchLink/LinkMode) set to 'SdkOnly'" />
+		<TestVariations Include="linkall" Description="Run with trimmer (MtouchLink/LinkMode) set to 'Full'" />
 	</ItemGroup>
 
 	<PropertyGroup Condition="'$(TestVariation)' == 'interpreter'">
 		<UseInterpreter>true</UseInterpreter>
 	</PropertyGroup>
 
+	<PropertyGroup Condition="'$(TestVariation)' == 'nativeaot'">
+		<PublishAot>true</PublishAot>
+		<_IsPublishing>true</_IsPublishing>
+	</PropertyGroup>
+
+	<PropertyGroup Condition="'$(TestVariation)' == 'linksdk'">
+		<MtouchLink>SdkOnly</MtouchLink>
+		<LinkMode>$(MtouchLink)</LinkMode>
+	</PropertyGroup>
+
+	<PropertyGroup Condition="'$(TestVariation)' == 'linkall'">
+		<MtouchLink>Full</MtouchLink>
+		<LinkMode>$(MtouchLink)</LinkMode>
+	</PropertyGroup>
+
 	<PropertyGroup Condition="'$(TestVariation)' == 'bundle-original-resources'">
 		<BundleOriginalResources>true</BundleOriginalResources>
 	</PropertyGroup>

diff --git a/tests/monotouch-test/Photos/LivePhotoEditingContextTest.cs b/tests/monotouch-test/Photos/LivePhotoEditingContextTest.cs
@@ -48,6 +48,17 @@ public void Linker ()
 		[UnconditionalSuppressMessage ("Trimming", "IL2026", Justification = "This test pokes at internals, so it's expected to not be trimmer safe. It works though, so unless something changes, we're going to assume it's trimmer-compatible.")]
 		[UnconditionalSuppressMessage ("Trimming", "IL2075", Justification = "This test pokes at internals, so it's expected to not be trimmer safe. It works though, so unless something changes, we're going to assume it's trimmer-compatible.")]
 		[Test]
+#if __MACOS__
+		[DynamicDependency ("Invoke", "ObjCRuntime.Trampolines.SDPHLivePhotoFrameProcessingBlock", "Microsoft.macOS")]
+#elif __TVOS__
+		[DynamicDependency ("Invoke", "ObjCRuntime.Trampolines.SDPHLivePhotoFrameProcessingBlock", "Microsoft.tvOS")]
+#elif __MACCATALYST__
+		[DynamicDependency ("Invoke", "ObjCRuntime.Trampolines.SDPHLivePhotoFrameProcessingBlock", "Microsoft.MacCatalyst")]
+#elif __IOS__
+		[DynamicDependency ("Invoke", "ObjCRuntime.Trampolines.SDPHLivePhotoFrameProcessingBlock", "Microsoft.iOS")]
+#else
+#error Unknown platform
+#endif
 		public unsafe void FrameProcessingBlock2 ()
 		{
 			if (!Runtime.DynamicRegistrationSupported)

diff --git a/tools/dotnet-linker/Steps/ManagedRegistrarLookupTablesStep.cs b/tools/dotnet-linker/Steps/ManagedRegistrarLookupTablesStep.cs
@@ -393,8 +393,14 @@ void GenerateConstructINativeObject (TypeDefinition registrarType)
 					var ctor = abr.CurrentAssembly.MainModule.ImportReference (ctorRef);
 
 					// we need to preserve the constructor because it might not be used anywhere else
-					if (IsTrimmed (ctor))
-						Annotations.Mark (ctor.Resolve ());
+					if (IsTrimmed (ctor)) {
+						var ctorDefinition = ctor.Resolve ();
+						Annotations.Mark (ctorDefinition);
+						foreach (var instr in ctorDefinition.Body.Instructions) {
+							if (instr.Operand is MethodReference mr)
+								Annotations.Mark (mr.Resolve ());
+						}
+					}
 
 					if (!ManagedRegistrarStep.IsOpenType (type)) {
 						EnsureVisible (createInstanceMethod, ctor);

diff --git a/tools/dotnet-linker/Steps/SetBeforeFieldInitStep.cs b/tools/dotnet-linker/Steps/SetBeforeFieldInitStep.cs
@@ -45,6 +45,12 @@ protected override void Process (TypeDefinition type)
 			if (Configuration.DerivedLinkContext.App.Optimizations.RegisterProtocols != true)
 				return;
 
+			if (Configuration.DerivedLinkContext.App.XamarinRuntime == Bundler.XamarinRuntime.NativeAOT) {
+				// We can't remove the static constructor in the trimmer if we're using NativeAOT,
+				// because NativeAOT needs it for its own trimming logic.
+				return;
+			}
+
 			if (!type.IsBeforeFieldInit && type.IsInterface && type.HasMethods) {
 				var cctor = type.GetTypeConstructor ();
 				if (cctor is not null && cctor.IsBindingImplOptimizableCode (LinkContext))

diff --git a/tools/linker/CoreOptimizeGeneratedCode.cs b/tools/linker/CoreOptimizeGeneratedCode.cs
@@ -1413,7 +1413,27 @@ bool ProcessProtocolInterfaceStaticConstructor (MethodDefinition method)
 			Driver.Log (4, "Optimized static constructor in the protocol interface {0} (static constructor was cleared and custom attributes removed)", method.DeclaringType.FullName);
 			method.Body.Instructions.Clear ();
 			method.Body.Instructions.Add (Instruction.Create (OpCodes.Ret));
-			method.CustomAttributes.Clear ();
+
+			// Only remove DynamicDependency attributes that takes a single string argument.
+			// The generator generates other DynamicDependency attributes, and we don't want to remove those.
+			for (var i = method.CustomAttributes.Count - 1; i >= 0; i--) {
+				var ca = method.CustomAttributes [i];
+
+				if (!ca.AttributeType.Is ("System.Diagnostics.CodeAnalysis", "DynamicDependencyAttribute"))
+					continue;
+
+				if (!ca.HasConstructorArguments)
+					continue;
+
+				if (ca.ConstructorArguments.Count != 1)
+					continue;
+
+				if (!ca.ConstructorArguments [0].Type.Is ("System", "String"))
+					continue;
+
+				method.CustomAttributes.RemoveAt (i);
+			}
+
 			return true;
 		}
 	}