ILLink: Add PropertyNode for dependency analysis (#102026)

Adds a node for PropertyDefinitions to the trimmers dependency analysis, and moves the body of MarkProperty to the node's GetStaticDependencies.

Author: jtschuster

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

@@ -15,6 +15,7 @@ internal sealed class NodeFactory (MarkStep markStep)
 			public MarkStep MarkStep { get; } = markStep;
 			readonly NodeCache<TypeDefinition, TypeDefinitionNode> _typeNodes = new (static t => new TypeDefinitionNode(t));
 			readonly NodeCache<MethodDefinition, MethodDefinitionNode> _methodNodes = new (static _ => throw new InvalidOperationException ("Creation of node requires more than the key."));
+			readonly NodeCache<PropertyDefinition, PropertyDefinitionNode> _propertyNodes = new (static p => new PropertyDefinitionNode(p));
 			readonly NodeCache<TypeDefinition, TypeIsRelevantToVariantCastingNode> _typeIsRelevantToVariantCastingNodes = new (static (t) => new TypeIsRelevantToVariantCastingNode (t));
 
 			internal TypeDefinitionNode GetTypeNode (TypeDefinition definition)
@@ -32,6 +33,11 @@ internal TypeIsRelevantToVariantCastingNode GetTypeIsRelevantToVariantCastingNod
 				return _typeIsRelevantToVariantCastingNodes.GetOrAdd (type);
 			}
 
+			internal PropertyDefinitionNode GetPropertyNode (PropertyDefinition prop)
+			{
+				return _propertyNodes.GetOrAdd (prop);
+			}
+
 			struct NodeCache<TKey, TValue> where TKey : notnull
 			{
 				// Change to concurrent dictionary if/when multithreaded marking is enabled

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

@@ -0,0 +1,46 @@
+// 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;
+using ILCompiler.DependencyAnalysisFramework;
+using Mono.Cecil;
+
+namespace Mono.Linker.Steps
+{
+
+	public partial class MarkStep
+	{
+		internal sealed class PropertyDefinitionNode : DependencyNodeCore<NodeFactory>
+		{
+			PropertyDefinition _property;
+			public PropertyDefinitionNode(PropertyDefinition property)
+			{
+				_property = property;
+			}
+
+			public override bool InterestingForDynamicDependencyAnalysis => false;
+
+			public override bool HasDynamicDependencies => false;
+
+			public override bool HasConditionalStaticDependencies => false;
+
+			public override bool StaticDependenciesAreComputed => true;
+
+			public override IEnumerable<CombinedDependencyListEntry>? GetConditionalStaticDependencies (NodeFactory context) => null;
+
+			public override IEnumerable<DependencyListEntry>? GetStaticDependencies (NodeFactory context)
+			{
+				var propertyOrigin = new MessageOrigin (_property);
+
+				// Consider making this more similar to MarkEvent method?
+				context.MarkStep.MarkCustomAttributes (_property, new DependencyInfo (DependencyKind.CustomAttribute, _property), propertyOrigin);
+				context.MarkStep.DoAdditionalPropertyProcessing (_property);
+				return null;
+			}
+
+			public override IEnumerable<CombinedDependencyListEntry>? SearchDynamicDependencies (List<DependencyNodeCore<NodeFactory>> markedNodes, int firstNode, NodeFactory context) => null;
+
+			protected override string GetName (NodeFactory context) => _property.GetDisplayName ();
+		}
+	}
+}

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

@@ -3498,11 +3498,8 @@ protected internal void MarkProperty (PropertyDefinition prop, in DependencyInfo
 			if (!Annotations.MarkProcessed (prop, reason))
 				return;
 
-			var propertyOrigin = new MessageOrigin (prop);
-
-			// Consider making this more similar to MarkEvent method?
-			MarkCustomAttributes (prop, new DependencyInfo (DependencyKind.CustomAttribute, prop), propertyOrigin);
-			DoAdditionalPropertyProcessing (prop);
+			PropertyDefinitionNode propertyNode = _nodeFactory.GetPropertyNode (prop);
+			_dependencyGraph.AddRoot (propertyNode, reason.Kind.ToString ());
 		}
 
 		protected internal virtual void MarkEvent (EventDefinition evt, in DependencyInfo reason, MessageOrigin origin)