Make default rooting behavior consistent (dotnet/linker#3124)

Now specifying an assembly as a root without any other qualifiers will default to rooting everything.

Commit migrated from dotnet/linker@e775974

src/tools/illink/src/ILLink.Tasks/LinkTask.cs

@@ -43,11 +43,8 @@ public class ILLink : ToolTask
 		/// <summary>
 		///   The names of the assemblies to root. This should contain
 		///   assembly names without an extension, not file names or
-		///   paths. Exactly which parts of the assemblies get rooted
-		///   is subject to change. Currently these get passed to
-		///   illink with "-a", which roots the entry point for
-		///   executables, and everything for libraries. To control
-		///   the behaviour explicitly, set RootMode metadata.
+		///   paths. The default is to root everything in these assemblies.
+		//    For more fine-grained control, set RootMode metadata.
 		/// </summary>
 		[Required]
 		public ITaskItem[] RootAssemblyNames { get; set; }

src/tools/illink/src/ILLink.Tasks/build/Microsoft.NET.ILLink.targets

@@ -279,9 +279,9 @@ Copyright (c) .NET Foundation. All rights reserved.
       <ManagedAssemblyToLink Include="@(_TrimmableManagedAssemblyToLink)" IsTrimmable="true" />
     </ItemGroup>
 
-    <!-- Root the main assembly, whether or not it has IsTrimmable set. -->
+    <!-- Root the main assembly entry point. -->
     <ItemGroup>
-      <TrimmerRootAssembly Include="@(IntermediateAssembly)" />
+      <TrimmerRootAssembly Include="@(IntermediateAssembly)" RootMode="EntryPoint" />
     </ItemGroup>
 
     <!-- For .NET < 6, root and copy assemblies without IsTrimmable=true MSBuild metadata. -->

src/tools/illink/src/linker/Linker.Steps/RootAssemblyInputStep.cs

@@ -42,11 +42,6 @@ protected override void Process ()
 			}
 
 			switch (rootMode) {
-			case AssemblyRootMode.Default:
-				if (assembly.MainModule.Kind == ModuleKind.Dll)
-					goto case AssemblyRootMode.AllMembers;
-				else
-					goto case AssemblyRootMode.EntryPoint;
 			case AssemblyRootMode.EntryPoint:
 				var ep = assembly.MainModule.EntryPoint;
 				if (ep == null) {

src/tools/illink/src/linker/Linker/AssemblyRootMode.cs

@@ -5,9 +5,8 @@ namespace Mono.Linker
 {
 	public enum AssemblyRootMode
 	{
-		Default = 0,
+		AllMembers = 0,
 		EntryPoint,
-		AllMembers,
 		VisibleMembers,
 		Library
 	}

src/tools/illink/src/linker/Linker/Driver.cs

@@ -639,10 +639,10 @@ protected int SetupContext (ILogger? customLogger = null)
 								return -1;
 							}
 
-							AssemblyRootMode rmode = AssemblyRootMode.Default;
+							AssemblyRootMode rmode = AssemblyRootMode.AllMembers;
 							var rootMode = GetNextStringValue ();
 							if (rootMode != null) {
-								var parsed_rmode = ParseAssemblyRootsMode (rootMode);
+								var parsed_rmode = ParseAssemblyRootMode (rootMode);
 								if (parsed_rmode is null)
 									return -1;
 
@@ -1115,11 +1115,9 @@ static string[] ReadLines (string file)
 			return null;
 		}
 
-		AssemblyRootMode? ParseAssemblyRootsMode (string s)
+		AssemblyRootMode? ParseAssemblyRootMode (string s)
 		{
 			switch (s.ToLowerInvariant ()) {
-			case "default":
-				return AssemblyRootMode.Default;
 			case "all":
 				return AssemblyRootMode.AllMembers;
 			case "visible":

src/tools/illink/test/ILLink.RoslynAnalyzer.Tests/generated/ILLink.RoslynAnalyzer.Tests.Generator/ILLink.RoslynAnalyzer.Tests.TestCaseGenerator/Inheritance.Interfaces.BaseProvidesInterfaceEdgeCaseTests.g.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace ILLink.RoslynAnalyzer.Tests.Inheritance.Interfaces
+{
+	public sealed partial class BaseProvidesInterfaceEdgeCaseTests : LinkerTestBase
+	{
+
+		protected override string TestSuiteName => "Inheritance.Interfaces.BaseProvidesInterfaceEdgeCase";
+
+		[Fact]
+		public Task BaseProvidesInterfaceMethodCircularReference ()
+		{
+			return RunTest (allowMissingWarnings: true);
+		}
+
+	}
+}

src/tools/illink/test/ILLink.Tasks.Tests/Mock.cs

@@ -178,7 +178,7 @@ public Dictionary<string, string> GetCustomData ()
 		protected override List<BaseStep> CreateDefaultResolvers ()
 		{
 			return new List<BaseStep> () {
-				new RootAssemblyInput (null, AssemblyRootMode.Default)
+				new RootAssemblyInput (null, AssemblyRootMode.EntryPoint)
 			};
 		}
 	}

src/tools/illink/test/Mono.Linker.Tests.Cases/Inheritance.Interfaces/StaticInterfaceMethods/StaticInterfaceMethodsInPreservedScope.cs

@@ -1,4 +1,4 @@
-// Copyright (c) .NET Foundation and contributors. All rights reserved.
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System;
@@ -15,7 +15,6 @@ namespace Mono.Linker.Tests.Cases.Inheritance.Interfaces.StaticInterfaceMethods
 {
 	[SetupCompileBefore ("library.dll", new[] { "Dependencies/Library.cs" })]
 	[SetupLinkerAction ("skip", "library")]
-	[SetupLinkerArgument ("-a", "test.exe")]
 	public static class StaticInterfaceMethodsInPreservedScope
 	{
 		[Kept]

src/tools/illink/test/Mono.Linker.Tests.Cases/Inheritance.Interfaces/StaticInterfaceMethods/StaticVirtualInterfaceMethodsInPreservedScope.cs

@@ -1,4 +1,4 @@
-// Copyright (c) .NET Foundation and contributors. All rights reserved.
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System;
@@ -15,7 +15,6 @@ namespace Mono.Linker.Tests.Cases.Inheritance.Interfaces.StaticInterfaceMethods
 {
 	[SetupCompileBefore ("library.dll", new[] { "Dependencies/Library.cs" })]
 	[SetupLinkerAction ("skip", "library")]
-	[SetupLinkerArgument ("-a", "test.exe")]
 	public static class StaticVirtualInterfaceMethodsInPreservedScope
 	{
 		[Kept]

src/tools/illink/test/Mono.Linker.Tests.Cases/Libraries/DefaultLibraryLinkBehavior.cs

@@ -1,9 +1,10 @@
-using Mono.Linker.Tests.Cases.Expectations.Assertions;
+using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;
 
 namespace Mono.Linker.Tests.Cases.Libraries
 {
 	[SetupCompileAsLibrary]
+	[SetupLinkerArgument ("-a", "test.dll")]
 	[Kept]
 	[KeptMember (".ctor()")]
 	public class DefaultLibraryLinkBehavior

src/tools/illink/test/Mono.Linker.Tests/TestCasesRunner/LinkerArgumentBuilder.cs

@@ -1,4 +1,4 @@
-// Copyright (c) .NET Foundation and contributors. All rights reserved.
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System.Collections.Generic;
@@ -61,6 +61,7 @@ public virtual void LinkFromAssembly (string fileName)
 		{
 			Append ("-a");
 			Append (fileName);
+			Append ("entrypoint");
 		}
 
 		public virtual void LinkFromPublicAndFamily (string fileName)