[dotnet-linker] Add PreserveSmartEnumConversionsSubStep into the pipeline.

tools/dotnet-linker/Compat.cs

@@ -119,6 +119,22 @@ public class Pipeline {
 	}
 }
 
+namespace Xamarin.Linker {
+	public class Profile {
+		public LinkerConfiguration Configuration { get; private set; }
+
+		public Profile (LinkerConfiguration config)
+		{
+			Configuration = config;
+		}
+
+		public bool IsProductAssembly (AssemblyDefinition assembly)
+		{
+			return assembly.Name.Name == Configuration.PlatformAssembly;
+		}
+	}
+}
+
 namespace Mono.Linker {
 	public static class LinkContextExtensions {
 		public static void LogMessage (this LinkContext context, string messsage)

tools/dotnet-linker/LinkerConfiguration.cs

@@ -10,6 +10,7 @@
 
 using Xamarin.Bundler;
 using Xamarin.Utils;
+using Xamarin.Tuner;
 
 using ObjCRuntime;
 
@@ -38,6 +39,7 @@ public class LinkerConfiguration {
 		public CompilerFlags CompilerFlags;
 
 		public LinkContext Context { get; private set; }
+		public Profile Profile { get; private set; }
 
 		// The list of assemblies is populated in CollectAssembliesStep.
 		public List<AssemblyDefinition> Assemblies = new List<AssemblyDefinition> ();
@@ -62,6 +64,7 @@ public static LinkerConfiguration GetInstance (LinkContext context)
 			if (!File.Exists (linker_file))
 				throw new FileNotFoundException ($"The custom linker file {linker_file} does not exist.");
 
+			Profile = new Profile (this);
 			Application = new Application (this);
 			Target = new Target (Application);
 			CompilerFlags = new CompilerFlags (Target);

tools/dotnet-linker/SetupStep.cs

@@ -55,6 +55,7 @@ protected override void Process ()
 				// [assembly: LinkSafe] attributes, which means we treat them as sdk assemblies and those may have
 				// Preserve attributes.
 				prelink_substeps.Add (new ApplyPreserveAttribute ());
+				prelink_substeps.Add (new PreserveSmartEnumConversionsSubStep ());
 			}
 
 			Steps.Add (new LoadNonSkippedAssembliesStep ());

tools/dotnet-linker/dotnet-linker.csproj

@@ -137,9 +137,15 @@
     <Compile Include="..\linker\ApplyPreserveAttribute.cs">
       <Link>external\tools\linker\ApplyPreserveAttribute.cs</Link>
     </Compile>
+    <Compile Include="..\linker\ExceptionalSubStep.cs">
+      <Link>external\tools\linker\ExceptionalSubStep.cs</Link>
+    </Compile>
     <Compile Include="..\linker\MonoTouch.Tuner\Extensions.cs">
       <Link>external\tools\linker\MonoTouch.Tuner\Extensions.cs</Link>
     </Compile>
+    <Compile Include="..\linker\MonoTouch.Tuner\PreserveSmartEnumConversionsSubStep.cs">
+      <Link>external\tools\linker\MonoTouch.Tuner\PreserveSmartEnumConversionsSubStep.cs</Link>
+    </Compile>
     <Compile Include="..\linker\MobileExtensions.cs">
       <Link>external\tools\linker\MobileExtensions.cs</Link>
     </Compile>

tools/linker/ExceptionalSubStep.cs

@@ -7,15 +7,40 @@
 
 using Xamarin.Tuner;
 
+#if NET
+using Mono.Linker;
+using Mono.Linker.Steps;
+#endif
+
 namespace Xamarin.Linker {
 
 	public abstract class ExceptionalSubStep : BaseSubStep {
 
 		protected DerivedLinkContext LinkContext {
 			get {
+#if NET
+				throw new NotImplementedException ();
+#else
 				return (DerivedLinkContext) base.context;
+#endif
+			}
+		}
+
+#if NET
+		protected LinkContext context {
+			get { return Context; }
+		}
+
+		protected LinkerConfiguration Configuration {
+			get { return LinkerConfiguration.GetInstance (Context);  }
+		}
+
+		protected Profile Profile {
+			get {
+				return Configuration.Profile;
 			}
 		}
+#endif
 
 		public override sealed void ProcessAssembly (AssemblyDefinition assembly)
 		{

tools/linker/MonoTouch.Tuner/PreserveSmartEnumConversionsSubStep.cs

@@ -7,7 +7,11 @@
 using Mono.Cecil.Cil;
 using Mono.Linker;
 using Mono.Tuner;
+#if NET
+using Mono.Linker.Steps;
+#else
 using MonoTouch.Tuner;
+#endif
 
 using Xamarin.Bundler;
 
@@ -21,7 +25,10 @@ public class PreserveSmartEnumConversionsSubStep : ExceptionalSubStep
 
 		public override SubStepTargets Targets {
 			get {
-				return SubStepTargets.Method | SubStepTargets.Property;
+				return
+					SubStepTargets.Method
+					| SubStepTargets.Type // SubStepTargets.Type is only needed to work around a linker bug: https://github.com/mono/linker/issues/1458
+					| SubStepTargets.Property;
 			}
 		}
 
@@ -41,6 +48,18 @@ public override bool IsActiveFor (AssemblyDefinition assembly)
 
 		void Preserve (Tuple<MethodDefinition, MethodDefinition> pair, MethodDefinition conditionA, MethodDefinition conditionB = null)
 		{
+#if NET
+			// The AddPreservedMethod (MethodDefinition, MethodDefinition) has not been exposed yet, so preserve the entire containing type instead.
+			// https://github.com/mono/linker/issues/1456
+			if (conditionA != null) {
+				context.Annotations.AddPreservedMethod (conditionA.DeclaringType, pair.Item1);
+				context.Annotations.AddPreservedMethod (conditionA.DeclaringType, pair.Item2);
+			}
+			if (conditionB != null) {
+				context.Annotations.AddPreservedMethod (conditionB.DeclaringType, pair.Item1);
+				context.Annotations.AddPreservedMethod (conditionB.DeclaringType, pair.Item2);
+			}
+#else
 			if (conditionA != null) {
 				context.Annotations.AddPreservedMethod (conditionA, pair.Item1);
 				context.Annotations.AddPreservedMethod (conditionA, pair.Item2);
@@ -49,6 +68,7 @@ void Preserve (Tuple<MethodDefinition, MethodDefinition> pair, MethodDefinition
 				context.Annotations.AddPreservedMethod (conditionB, pair.Item1);
 				context.Annotations.AddPreservedMethod (conditionB, pair.Item2);
 			}
+#endif
 		}
 
 		void ProcessAttributeProvider (ICustomAttributeProvider provider, MethodDefinition conditionA, MethodDefinition conditionB = null)