Changes to make sharing code with Native AOT easier

src/ILLink.RoslynAnalyzer/TrimAnalysis/FlowAnnotations.cs

@@ -1,6 +1,7 @@
 // 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;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using ILLink.RoslynAnalyzer;
@@ -9,8 +10,17 @@
 
 namespace ILLink.Shared.TrimAnalysis
 {
-	readonly partial struct FlowAnnotations
+	partial class FlowAnnotations
 	{
+		// In the analyzer there's no stateful data the flow annotations need to store
+		// so we just create a singleton on demand.
+		static readonly Lazy<FlowAnnotations> _instance = new (() => new FlowAnnotations (), isThreadSafe: true);
+
+		public static FlowAnnotations Instance { get => _instance.Value; }
+
+		// Hide the default .ctor so that only the one singleton instance can be created
+		private FlowAnnotations () { }
+
 		public static bool RequiresDataFlowAnalysis (IMethodSymbol method)
 		{
 			if (method.GetDynamicallyAccessedMemberTypes () != DynamicallyAccessedMemberTypes.None)
@@ -72,13 +82,13 @@ public static DynamicallyAccessedMemberTypes GetMethodReturnValueAnnotation (IMe
 		// In linker this is an optimization to avoid the heavy lifting of analysis if there's no point
 		// it's unclear if the same optimization makes sense for the analyzer.
 		internal partial bool MethodRequiresDataFlowAnalysis (MethodProxy method)
-			=> FlowAnnotations.RequiresDataFlowAnalysis (method.Method);
+			=> RequiresDataFlowAnalysis (method.Method);
 
 		internal partial MethodReturnValue GetMethodReturnValue (MethodProxy method, DynamicallyAccessedMemberTypes dynamicallyAccessedMemberTypes)
 			=> new MethodReturnValue (method.Method, dynamicallyAccessedMemberTypes);
 
 		internal partial MethodReturnValue GetMethodReturnValue (MethodProxy method)
-			=> GetMethodReturnValue (method, FlowAnnotations.GetMethodReturnValueAnnotation (method.Method));
+			=> GetMethodReturnValue (method, GetMethodReturnValueAnnotation (method.Method));
 
 		internal partial GenericParameterValue GetGenericParameterValue (GenericParameterProxy genericParameter)
 			=> new GenericParameterValue (genericParameter.TypeParameterSymbol);
@@ -94,7 +104,7 @@ internal partial MethodParameterValue GetMethodParameterValue (MethodProxy metho
 
 		internal partial MethodParameterValue GetMethodParameterValue (MethodProxy method, int parameterIndex)
 		{
-			var annotation = FlowAnnotations.GetMethodParameterAnnotation (method.Method.Parameters[parameterIndex]);
+			var annotation = GetMethodParameterAnnotation (method.Method.Parameters[parameterIndex]);
 			return GetMethodParameterValue (method, parameterIndex, annotation);
 		}
 #pragma warning restore CA1822

src/ILLink.RoslynAnalyzer/TrimAnalysis/HandleCallAction.cs

@@ -26,7 +26,7 @@ public HandleCallAction (in DiagnosticContext diagnosticContext, ISymbol owningS
 			_owningSymbol = owningSymbol;
 			_operation = operation;
 			_diagnosticContext = diagnosticContext;
-			_annotations = new FlowAnnotations ();
+			_annotations = FlowAnnotations.Instance;
 			_reflectionAccessAnalyzer = new ReflectionAccessAnalyzer ();
 			_requireDynamicallyAccessedMembersAction = new (diagnosticContext, _reflectionAccessAnalyzer);
 		}

src/ILLink.Shared/Annotations.cs

@@ -8,6 +8,9 @@
 using System.Linq;
 using ILLink.Shared.TrimAnalysis;
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared
 {
 	// Temporary workaround - should be removed once linker can be upgraded to build against

src/ILLink.Shared/DataFlow/DefaultValueDictionary.cs

@@ -7,6 +7,9 @@
 using System.Linq;
 using System.Text;
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared.DataFlow
 {
 	// This is a dictionary along with a default value, where every possible key either maps to

src/ILLink.Shared/DataFlow/DictionaryLattice.cs

@@ -3,6 +3,9 @@
 
 using System;
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared.DataFlow
 {
 	// A lattice over dictionaries where the stored values are also from a lattice.

src/ILLink.Shared/DataFlow/ForwardDataFlowAnalysis.cs

@@ -5,6 +5,9 @@
 using System.Collections.Generic;
 using System.Diagnostics;
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared.DataFlow
 {
 	// A generic implementation of a forward dataflow analysis. Forward means that it flows facts

src/ILLink.Shared/DataFlow/IControlFlowGraph.cs

@@ -6,6 +6,9 @@
 using System.Collections.Immutable;
 using System.Diagnostics.CodeAnalysis;
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared.DataFlow
 {
 	public enum RegionKind

src/ILLink.Shared/DataFlow/IDataFlowState.cs

@@ -3,6 +3,9 @@
 
 using System;
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared.DataFlow
 {
 	public sealed class Box<T> where T : struct

src/ILLink.Shared/DataFlow/IDeepCopyValue.cs

@@ -1,6 +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.
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared.DataFlow
 {
 	// Adds ability to deep copy a value

src/ILLink.Shared/DataFlow/ILattice.cs

@@ -3,6 +3,9 @@
 
 using System;
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared.DataFlow
 {
 	// ILattice represents a lattice (technically a semilattice) of values.

src/ILLink.Shared/DataFlow/ITransfer.cs

@@ -3,6 +3,9 @@
 
 using System;
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared.DataFlow
 {
 	// ITransfer represents the transfer functions for a dataflow analysis.

src/ILLink.Shared/DataFlow/SingleValue.cs

@@ -1,6 +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.
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared.DataFlow
 {
 	// This is a sum type over the various kinds of values we track:

src/ILLink.Shared/DataFlow/ValueSet.cs

@@ -7,6 +7,9 @@
 using System.Linq;
 using System.Text;
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared.DataFlow
 {
 	public readonly struct ValueSet<TValue> : IEquatable<ValueSet<TValue>>, IEnumerable<TValue>

src/ILLink.Shared/DataFlow/ValueSetLattice.cs

@@ -3,6 +3,9 @@
 
 using System;
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared.DataFlow
 {
 	// A lattice over ValueSets where the Meet operation is just set union.

src/ILLink.Shared/DiagnosticCategory.cs

@@ -1,6 +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.
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared
 {
 	internal static class DiagnosticCategory

src/ILLink.Shared/DiagnosticId.cs

@@ -1,6 +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.
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared
 {
 	public enum DiagnosticId

src/ILLink.Shared/DiagnosticString.cs

@@ -3,6 +3,9 @@
 
 using System;
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared
 {
 	public readonly struct DiagnosticString

src/ILLink.Shared/HashUtils.cs

@@ -5,6 +5,9 @@
 using System;
 #endif
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared
 {
 	static class HashUtils

src/ILLink.Shared/IsExternalInit.cs

@@ -1,6 +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.
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 #if NETSTANDARD
 // Allow use of init setters on downlevel frameworks.
 namespace System.Runtime.CompilerServices

src/ILLink.Shared/MessageFormat.cs

@@ -1,6 +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.
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared
 {
 	internal static class MessageFormat

src/ILLink.Shared/MessageSubCategory.cs

@@ -1,9 +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.
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared
 {
-	internal static class MessageSubCategory
+	public static class MessageSubCategory
 	{
 		public const string None = "";
 		public const string TrimAnalysis = "Trim analysis";

src/ILLink.Shared/TrimAnalysis/ArrayValue.cs

@@ -4,6 +4,9 @@
 using ILLink.Shared.DataFlow;
 using MultiValue = ILLink.Shared.DataFlow.ValueSet<ILLink.Shared.DataFlow.SingleValue>;
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared.TrimAnalysis
 {
 	sealed partial record ArrayValue : SingleValue

src/ILLink.Shared/TrimAnalysis/ConstIntValue.cs

@@ -3,6 +3,9 @@
 
 using ILLink.Shared.DataFlow;
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared.TrimAnalysis
 {
 	/// <summary>

src/ILLink.Shared/TrimAnalysis/DiagnosticContext.cs

@@ -1,6 +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.
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared.TrimAnalysis
 {
 	readonly partial struct DiagnosticContext

src/ILLink.Shared/TrimAnalysis/FieldValue.cs

@@ -1,6 +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.
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared.TrimAnalysis
 {
 	sealed partial record FieldValue : ValueWithDynamicallyAccessedMembers;

src/ILLink.Shared/TrimAnalysis/FlowAnnotations.cs

@@ -4,10 +4,13 @@
 using System.Diagnostics.CodeAnalysis;
 using ILLink.Shared.TypeSystemProxy;
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared.TrimAnalysis
 {
 	// Shared helpers to go from MethodProxy to dataflow values.
-	readonly partial struct FlowAnnotations
+	partial class FlowAnnotations
 	{
 		internal partial bool MethodRequiresDataFlowAnalysis (MethodProxy method);
 

src/ILLink.Shared/TrimAnalysis/GenericParameterValue.cs

@@ -3,6 +3,9 @@
 
 using ILLink.Shared.TypeSystemProxy;
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared.TrimAnalysis
 {
 	/// <summary>

src/ILLink.Shared/TrimAnalysis/HandleCallAction.cs

@@ -13,6 +13,9 @@
 using ILLink.Shared.TypeSystemProxy;
 using MultiValue = ILLink.Shared.DataFlow.ValueSet<ILLink.Shared.DataFlow.SingleValue>;
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared.TrimAnalysis
 {
 	[StructLayout (LayoutKind.Auto)] // A good way to avoid CS0282, we don't really care about field order
@@ -1161,6 +1164,10 @@ GenericParameterValue genericParam
 			// Disable warnings for all unimplemented intrinsics. Some intrinsic methods have annotations, but analyzing them
 			// would produce unnecessary warnings even for cases that are intrinsically handled. So we disable handling these calls
 			// until a proper intrinsic handling is made
+			// NOTE: Currently this is done "for the analyzer" and it relies on linker/NativeAOT to not call HandleCallAction
+			// for intrinsics which linker/NativeAOT need special handling for or those which are not implemented here and only there.
+			// Ideally we would run everything through HandleCallAction and it would return "false" for intrinsics it doesn't handle
+			// like it already does for Activator.CreateInstance<T> for example.
 			default:
 				methodReturnValue = MultiValueLattice.Top;
 				return true;

src/ILLink.Shared/TrimAnalysis/IntrinsicId.cs

@@ -1,6 +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.
 
+// This is needed due to NativeAOT which doesn't enable nullable globally yet
+#nullable enable
+
 namespace ILLink.Shared.TrimAnalysis
 {
 	enum IntrinsicId
@@ -43,6 +46,12 @@ enum IntrinsicId
 		Expression_Field,
 		Expression_Property,
 		Expression_New,
+		Enum_GetValues,
+		Marshal_SizeOf,
+		Marshal_OffsetOf,
+		Marshal_PtrToStructure,
+		Marshal_DestroyStructure,
+		Marshal_GetDelegateForFunctionPointer,
 		Activator_CreateInstance_Type,
 		Activator_CreateInstance_AssemblyName_TypeName,
 		Activator_CreateInstanceFrom,