Avoid copy action for root assemblies

src/libraries/Common/tests/TestUtilities/System/PlatformDetection.cs

@@ -280,6 +280,7 @@ public static bool IsMetadataTokenSupported
         // Changed to `true` when trimming
         public static bool IsBuiltWithAggressiveTrimming => IsNativeAot;
         public static bool IsNotBuiltWithAggressiveTrimming => !IsBuiltWithAggressiveTrimming;
+        public static bool IsTrimmedWithILLink => IsBuiltWithAggressiveTrimming && !IsNativeAot;
 
         // Windows - Schannel supports alpn from win8.1/2012 R2 and higher.
         // Linux - OpenSsl supports alpn from openssl 1.0.2 and higher.

src/libraries/System.Runtime.Loader/tests/System.Runtime.Loader.Tests.csproj

@@ -72,19 +72,20 @@
     <TrimmerRootDescriptor Include="$(MSBuildThisFileDirectory)ILLink.Descriptors.xml" />
   </ItemGroup>
 
-  <Target Name="PreserveEnCAssembliesFromLinking" Condition="'$(TargetOS)' == 'browser' and '$(EnableAggressiveTrimming)' == 'true'" BeforeTargets="ConfigureTrimming">
+  <Target Name="PreserveEnCAssembliesFromLinking" Condition="'$(TargetOS)' == 'browser' and '$(EnableAggressiveTrimming)' == 'true'" BeforeTargets="PrepareForILLink">
     <ItemGroup>
-      <!-- want to compute the intersection: apply update test assemblies that are also resolved to publish.
+      <!-- want to compute the intersection: apply update test assemblies that are also resolved to link.
         -->
       <ApplyUpdateTestProjectReference Include="@(ProjectReference)" Condition="$([System.String]::new('%(FileName)').StartsWith('$(ApplyUpdateTestPrefix)'))" />
       <ApplyUpdateTestAssemblyName Include="@(ApplyUpdateTestProjectReference->'%(FileName).dll')" />
-      <ResolvedFileToPublishNoDirName Include="%(ResolvedFileToPublish.FileName)%(ResolvedFileToPublish.Extension)">
-        <ResolvedFileToPublish>%(ResolvedFileToPublish.FullPath)</ResolvedFileToPublish>
-      </ResolvedFileToPublishNoDirName>
-      <ResolvedApplyUpdateAssembly Include="@(ResolvedFileToPublishNoDirName)" Condition="'@(ResolvedFileToPublishNoDirName)' == '@(ApplyUpdateTestAssemblyName)' and %(Identity) != ''" />
       <!-- Don't let the IL linker modify EnC test assemblies -->
-      <TrimmerRootAssembly Include="%(ResolvedApplyUpdateAssembly.ResolvedFileToPublish)" />
-    </ItemGroup>
+      <ManagedAssemblyToLink Condition="'%(FileName)%(Extension)' == '@(ApplyUpdateTestAssemblyName)'">
+        <TrimMode>copy</TrimMode>
+      </ManagedAssemblyToLink>
+      <ManagedAssemblyToLink Condition="'%(FileName)%(Extension)' == '@(IntermediateAssembly->'%(FileName)%(Extension)')'">
+        <TrimMode>copy</TrimMode>
+      </ManagedAssemblyToLink>
+    </ItemGroup> 
   </Target>
 
   <Target Name="IncludeDeltasInWasmBundle" BeforeTargets="PrepareForWasmBuildApp" Condition="'$(TargetOS)' == 'browser'">

src/libraries/System.Runtime/tests/System.Reflection.Tests/MemberInfoTests.cs

@@ -166,7 +166,8 @@ public void MethodInfoReflectedTypeDoesNotSurviveRuntimeHandles()
         }
 
         [Fact]
-        [ActiveIssue("https://github.com/dotnet/runtimelab/issues/830", typeof(PlatformDetection), nameof(PlatformDetection.IsNativeAot))]
+        [ActiveIssue("https://github.com/dotnet/linker/issues/2078", typeof(PlatformDetection), nameof(PlatformDetection.IsBuiltWithAggressiveTrimming)),
+            /* Stripping ComVisible because descriptors tell us so */]
         public void GetCustomAttributesData()
         {
             MemberInfo[] m = typeof(MemberInfoTests).GetMember("SampleClass");

src/libraries/System.Runtime/tests/System.Runtime.Tests/System.Runtime.Tests.csproj

@@ -14,6 +14,8 @@
 
     <!-- The test is looking for debugger attributes we would have stripped with NativeAOT -->
     <IlcKeepManagedDebuggerSupport>true</IlcKeepManagedDebuggerSupport>
+    <!-- Same for ILLink -->
+    <DebuggerSupport>true</DebuggerSupport>
   </PropertyGroup>
 
   <!--

src/libraries/System.Runtime/tests/System.Runtime.Tests/System/AttributeTests.cs

@@ -154,7 +154,7 @@ class ChildAttributeWithField : ParentAttribute
             public int Field = 0;
         }
 
-        [ActiveIssue("https://github.com/dotnet/runtimelab/issues/803", typeof(PlatformDetection), nameof(PlatformDetection.IsNativeAot))]
+        [ActiveIssue("https://github.com/dotnet/runtimelab/issues/803", typeof(PlatformDetection), nameof(PlatformDetection.IsBuiltWithAggressiveTrimming))]
         [Fact]
         [StringValue("\uDFFF")]
         public static void StringArgument_InvalidCodeUnits_FallbackUsed()

src/libraries/System.Runtime/tests/System.Runtime.Tests/System/Attributes.cs

@@ -44,7 +44,8 @@ public void TestIsDefined()
         }
 
         [Fact]
-        [ActiveIssue("https://github.com/dotnet/linker/issues/2078", typeof(PlatformDetection), nameof(PlatformDetection.IsNativeAot) /* Stripping ComVisible because descriptors tell us so */)]
+        [ActiveIssue("https://github.com/dotnet/linker/issues/2078", typeof(PlatformDetection), nameof(PlatformDetection.IsBuiltWithAggressiveTrimming)
+            /* Stripping ComVisible because descriptors tell us so */)]
         public void IsDefined_PropertyInfo()
         {
             PropertyInfo pi = typeof(TestBase).GetProperty("PropBase3");
@@ -327,6 +328,8 @@ public static class GetCustomAttribute
     {
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/linker/issues/2078", typeof(PlatformDetection), nameof(PlatformDetection.IsTrimmedWithILLink))
+            /* Stripping security attributes removes UnverifiableCodeAttribute */]
         public static void customAttributeCount()
         {
             List<CustomAttributeData> customAttributes = typeof(GetCustomAttribute).Module.CustomAttributes.ToList();

src/libraries/System.Runtime/tests/System.Runtime.Tests/System/Reflection/CustomAttributeDataTests.cs

@@ -75,7 +75,8 @@ public static void Test_CustomAttribute_Constructor_CrossAssembly1()
 
         [Fact]
         [ComVisible(false)]
-        [ActiveIssue("https://github.com/dotnet/linker/issues/2078", typeof(PlatformDetection), nameof(PlatformDetection.IsNativeAot)) /* Descriptors tell us to remove ComVisibleAttribute */]
+        [ActiveIssue("https://github.com/dotnet/linker/issues/2078", typeof(PlatformDetection), nameof(PlatformDetection.IsBuiltWithAggressiveTrimming))
+            /* Descriptors tell us to remove ComVisibleAttribute */]
         public static void Test_CustomAttribute_Constructor_CrossAssembly2()
         {
             MethodInfo m = (MethodInfo)MethodBase.GetCurrentMethod();

src/tools/illink/src/linker/CompatibilitySuppressions.xml

@@ -1147,6 +1147,12 @@
     <Left>ref/net8.0/illink.dll</Left>
     <Right>lib/net8.0/illink.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Mono.Linker.AnnotationStore.IsRootAssembly(Mono.Cecil.AssemblyDefinition)</Target>
+    <Left>ref/net8.0/illink.dll</Left>
+    <Right>lib/net8.0/illink.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>M:Mono.Linker.AnnotationStore.Mark(Mono.Cecil.CustomAttribute,Mono.Linker.DependencyInfo@)</Target>
@@ -1243,6 +1249,12 @@
     <Left>ref/net8.0/illink.dll</Left>
     <Right>lib/net8.0/illink.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Mono.Linker.AnnotationStore.SetRootAssembly(Mono.Cecil.AssemblyDefinition)</Target>
+    <Left>ref/net8.0/illink.dll</Left>
+    <Right>lib/net8.0/illink.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>M:Mono.Linker.AnnotationStore.SetSubstitutedInit(Mono.Cecil.TypeDefinition)</Target>

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

@@ -153,6 +153,7 @@ internal DynamicallyAccessedMembersTypeHierarchy DynamicallyAccessedMembersTypeH
 			DependencyKind.InterfaceImplementationInterfaceType,
 			DependencyKind.Ldtoken,
 			DependencyKind.ModifierType,
+			DependencyKind.NestedType,
 			DependencyKind.InstructionTypeRef,
 			DependencyKind.ParameterType,
 			DependencyKind.ReferencedBySpecialAttribute,
@@ -373,7 +374,7 @@ internal void MarkEntireType (TypeDefinition type, in DependencyInfo reason)
 					MarkEntireType (nested, new DependencyInfo (DependencyKind.NestedType, type));
 			}
 
-			Annotations.Mark (type, reason, ScopeStack.CurrentScope.Origin);
+			MarkTypeVisibleToReflection (type, type, reason, ScopeStack.CurrentScope.Origin);
 			MarkCustomAttributes (type, new DependencyInfo (DependencyKind.CustomAttribute, type));
 			MarkTypeSpecialCustomAttributes (type);
 
@@ -386,26 +387,27 @@ internal void MarkEntireType (TypeDefinition type, in DependencyInfo reason)
 
 			if (type.HasFields) {
 				foreach (FieldDefinition field in type.Fields) {
-					MarkField (field, new DependencyInfo (DependencyKind.MemberOfType, type), ScopeStack.CurrentScope.Origin);
+					MarkFieldVisibleToReflection (field, new DependencyInfo (DependencyKind.MemberOfType, type), ScopeStack.CurrentScope.Origin);
 				}
 			}
 
 			if (type.HasMethods) {
 				foreach (MethodDefinition method in type.Methods) {
-					Annotations.SetAction (method, MethodAction.ForceParse);
-					MarkMethod (method, new DependencyInfo (DependencyKind.MemberOfType, type), ScopeStack.CurrentScope.Origin);
+					if (IsFullyPreservedAction (Annotations.GetAction (type.Module.Assembly)))
+						Annotations.SetAction (method, MethodAction.ForceParse);
+					MarkMethodVisibleToReflection (method, new DependencyInfo (DependencyKind.MemberOfType, type), ScopeStack.CurrentScope.Origin);
 				}
 			}
 
 			if (type.HasProperties) {
 				foreach (var property in type.Properties) {
-					MarkProperty (property, new DependencyInfo (DependencyKind.MemberOfType, type));
+					MarkPropertyVisibleToReflection (property, new DependencyInfo (DependencyKind.MemberOfType, type), ScopeStack.CurrentScope.Origin);
 				}
 			}
 
 			if (type.HasEvents) {
 				foreach (var ev in type.Events) {
-					MarkEvent (ev, new DependencyInfo (DependencyKind.MemberOfType, type));
+					MarkEventVisibleToReflection (ev, new DependencyInfo (DependencyKind.MemberOfType, type), ScopeStack.CurrentScope.Origin);
 				}
 			}
 		}
@@ -1422,6 +1424,8 @@ protected virtual void MarkAssembly (AssemblyDefinition assembly, DependencyInfo
 					MarkEntireAssembly (assembly);
 				}
 				return;
+			} else if (Annotations.IsRootAssembly (assembly)) {
+				MarkEntireAssembly (assembly);
 			}
 
 			ProcessModuleType (assembly);
@@ -2033,7 +2037,9 @@ internal void MarkStaticConstructorVisibleToReflection (TypeDefinition type, in
 				// will call MarkType on the attribute type itself).
 				// If for some reason we do keep the attribute type (could be because of previous reference which would cause IL2045
 				// or because of a copy assembly with a reference and so on) then we should not spam the warnings due to the type itself.
-				if (!(reason.Source is IMemberDefinition sourceMemberDefinition && sourceMemberDefinition.DeclaringType == type))
+				// Also don't warn when the type is marked due to an assembly being rooted.
+				if (!(reason.Source is IMemberDefinition sourceMemberDefinition && sourceMemberDefinition.DeclaringType == type) &&
+					reason.Kind is not DependencyKind.TypeInAssembly)
 					Context.LogWarning (ScopeStack.CurrentScope.Origin, DiagnosticId.AttributeIsReferencedButTrimmerRemoveAllInstances, type.GetDisplayName ());
 			}
 

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

@@ -87,7 +87,8 @@ protected override void Process ()
 				Context.MetadataTrimming = MetadataTrimming.None;
 				break;
 			case AssemblyRootMode.AllMembers:
-				Context.Annotations.SetAction (assembly, AssemblyAction.Copy);
+				Annotations.SetRootAssembly (assembly);
+				Annotations.Mark (assembly.MainModule, di, origin);
 				return;
 			}
 		}

src/tools/illink/src/linker/Linker.Steps/UnreachableBlocksOptimizer.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;
@@ -1583,7 +1583,7 @@ public bool Analyze (in CalleePayload callee, Stack<MethodDefinition> callStack)
 								return false;
 
 							if (operand is int oint) {
-								if (oint == 1)
+								if (oint != 0)
 									jmpTarget = (Instruction) instr.Operand;
 
 								continue;

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

@@ -59,6 +59,7 @@ public partial class AnnotationStore
 		protected readonly Dictionary<TypeDefinition, TypePreserveMembers> preserved_type_members = new ();
 		protected readonly Dictionary<ExportedType, TypePreserveMembers> preserved_exportedtype_members = new ();
 		protected readonly Dictionary<IMemberDefinition, List<MethodDefinition>> preserved_methods = new Dictionary<IMemberDefinition, List<MethodDefinition>> ();
+		readonly HashSet<AssemblyDefinition> assemblies_with_root_all_members = new ();
 		protected readonly HashSet<IMetadataTokenProvider> public_api = new HashSet<IMetadataTokenProvider> ();
 		protected readonly Dictionary<AssemblyDefinition, ISymbolReader> symbol_readers = new Dictionary<AssemblyDefinition, ISymbolReader> ();
 		readonly Dictionary<IMemberDefinition, LinkerAttributesInformation> linker_attributes = new Dictionary<IMemberDefinition, LinkerAttributesInformation> ();
@@ -399,6 +400,16 @@ public bool TryGetPreservedMembers (ExportedType type, out TypePreserveMembers p
 			return preserved_exportedtype_members.TryGetValue (type, out preserve);
 		}
 
+		public void SetRootAssembly (AssemblyDefinition assembly)
+		{
+			assemblies_with_root_all_members.Add (assembly);
+		}
+
+		public bool IsRootAssembly (AssemblyDefinition assembly)
+		{
+			return assemblies_with_root_all_members.Contains (assembly);
+		}
+
 		public bool TryGetMethodStubValue (MethodDefinition method, out object? value)
 		{
 			return MemberActions.TryGetMethodStubValue (method, out value);

src/tools/illink/test/Mono.Linker.Tests.Cases.Expectations/Metadata/SetupLinkerLinkAllAttribute.cs

@@ -0,0 +1,12 @@
+// 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;
+
+namespace Mono.Linker.Tests.Cases.Expectations.Metadata
+{
+	[AttributeUsage (AttributeTargets.Class, AllowMultiple = false)]
+	public class SetupLinkerLinkAllAttribute : BaseMetadataAttribute
+	{
+	}
+}

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

@@ -1,3 +1,6 @@
+// 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 Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;
 
@@ -6,12 +9,12 @@ namespace Mono.Linker.Tests.Cases.Libraries
 	[IgnoreTestCase ("NativeAOT doesn't implement library trimming the same way", IgnoredBy = Tool.NativeAot)]
 	[KeptAttributeAttribute (typeof (IgnoreTestCaseAttribute), By = Tool.Trimmer)]
 	[SetupCompileAsLibrary]
-	[SetupLinkerArgument ("-a", "test.dll")]
+	[SetupLinkerLinkAll]
 	[Kept]
 	[KeptMember (".ctor()")]
 	public class DefaultLibraryLinkBehavior
 	{
-		// Kept because by default libraries their action set to copy
+		// Kept because by default libraries have all members rooted
 		[Kept]
 		public static void Main ()
 		{

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

@@ -0,0 +1,56 @@
+// 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.Diagnostics.CodeAnalysis;
+using System.Runtime.CompilerServices;
+using Mono.Linker.Tests.Cases.Libraries.Dependencies;
+
+#if RootAllLibrary
+[assembly: TypeForwardedTo (typeof (RootAllLibrary_ExportedType))]
+#endif
+
+namespace Mono.Linker.Tests.Cases.Libraries.Dependencies
+{
+	public class RootAllLibrary
+	{
+		public static void Public ()
+		{
+		}
+
+		private static void Private ()
+		{
+		}
+
+		private class NestedType
+		{
+		}
+
+		public static void RemovedBranch ()
+		{
+			if (SubstitutedProperty)
+				RootAllLibrary_OptionalDependency.Use ();
+		}
+
+		// Substituted to false in RootAllLibrary_Substitutions.xml
+		static bool SubstitutedProperty {
+			get {
+				RequiresUnreferencedCode ();
+				return true;
+			}
+		}
+
+		[RequiresUnreferencedCode (nameof (RequiresUnreferencedCode))]
+		static void RequiresUnreferencedCode ()
+		{
+		}
+
+		[RootAllLibrary_RemovedAttribute]
+		class TypeWithRemovedAttribute
+		{
+		}
+	}
+
+	class NonPublicType
+	{
+	}
+}

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

@@ -0,0 +1,9 @@
+// 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.
+
+namespace Mono.Linker.Tests.Cases.Libraries.Dependencies
+{
+	public class RootAllLibrary_ExportedType
+	{
+	}
+}

src/tools/illink/test/Mono.Linker.Tests.Cases/Libraries/Dependencies/RootAllLibrary_LinkAttributes.xml

@@ -0,0 +1,7 @@
+<linker>
+    <assembly fullname="removedattribute">
+        <type fullname="Mono.Linker.Tests.Cases.Libraries.Dependencies.RootAllLibrary_RemovedAttribute">
+            <attribute internal="RemoveAttributeInstances" />
+        </type>
+    </assembly>
+</linker>

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

@@ -0,0 +1,12 @@
+using System.Diagnostics.CodeAnalysis;
+
+namespace Mono.Linker.Tests.Cases.Libraries.Dependencies
+{
+	public class RootAllLibrary_OptionalDependency
+	{
+		[RequiresUnreferencedCode (nameof (RootAllLibrary_OptionalDependency))]
+		public static void Use ()
+		{
+		}
+	}
+}

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

@@ -0,0 +1,8 @@
+using System;
+
+namespace Mono.Linker.Tests.Cases.Libraries.Dependencies
+{
+	public class RootAllLibrary_RemovedAttribute : Attribute
+	{
+	}
+}

src/tools/illink/test/Mono.Linker.Tests.Cases/Libraries/Dependencies/RootAllLibrary_Substitutions.xml

@@ -0,0 +1,7 @@
+<linker>
+    <assembly fullname="library">
+        <type fullname="Mono.Linker.Tests.Cases.Libraries.Dependencies.RootAllLibrary">
+            <method signature="System.Boolean get_SubstitutedProperty()" body="stub" value="false" />
+        </type>
+    </assembly>
+</linker>