Make TypeComponentsCache trimmable (dotnet#80726)

Contributes to dotnet#80165.

Dispensing of reflection member infos is done through a member policies class. This is a generic class that has specialized implementations for each kind of member info.

It used a clever trick to get to the specific implementations. Just access `MemberPolicies<EventInfo>.Default` to get one for events or `MemberPolicies<PropertyInfo>.Default` to get one for properties. It was also absolutely not trimming friendly.

This change removes the clever trick and replaces it with good old fashioned parameter passing.

src/coreclr/nativeaot/System.Private.CoreLib/src/System/Reflection/Runtime/BindingFlagSupport/ConstructorPolicies.cs

@@ -13,6 +13,10 @@ namespace System.Reflection.Runtime.BindingFlagSupport
     //==========================================================================================================================
     internal sealed class ConstructorPolicies : MemberPolicies<ConstructorInfo>
     {
+        public static readonly ConstructorPolicies Instance = new ConstructorPolicies();
+
+        public ConstructorPolicies() : base(MemberTypeIndex.Constructor) { }
+
         [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2070:UnrecognizedReflectionPattern",
             Justification = "Reflection implementation")]
         public sealed override IEnumerable<ConstructorInfo> GetDeclaredMembers(TypeInfo typeInfo)

src/coreclr/nativeaot/System.Private.CoreLib/src/System/Reflection/Runtime/BindingFlagSupport/EventPolicies.cs

@@ -13,6 +13,10 @@ namespace System.Reflection.Runtime.BindingFlagSupport
     //==========================================================================================================================
     internal sealed class EventPolicies : MemberPolicies<EventInfo>
     {
+        public static readonly EventPolicies Instance = new EventPolicies();
+
+        public EventPolicies() : base(MemberTypeIndex.Event) { }
+
         [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2070:UnrecognizedReflectionPattern",
             Justification = "Reflection implementation")]
         public sealed override IEnumerable<EventInfo> GetDeclaredMembers(TypeInfo typeInfo)
@@ -67,7 +71,7 @@ public sealed override bool ImplicitlyOverrides(EventInfo? baseMember, EventInfo
         {
             MethodInfo? baseAccessor = GetAccessorMethod(baseMember!);
             MethodInfo? derivedAccessor = GetAccessorMethod(derivedMember!);
-            return MemberPolicies<MethodInfo>.Default.ImplicitlyOverrides(baseAccessor, derivedAccessor);
+            return MethodPolicies.Instance.ImplicitlyOverrides(baseAccessor, derivedAccessor);
         }
 
         public sealed override bool OkToIgnoreAmbiguity(EventInfo m1, EventInfo m2)

src/coreclr/nativeaot/System.Private.CoreLib/src/System/Reflection/Runtime/BindingFlagSupport/FieldPolicies.cs

@@ -13,6 +13,10 @@ namespace System.Reflection.Runtime.BindingFlagSupport
     //==========================================================================================================================
     internal sealed class FieldPolicies : MemberPolicies<FieldInfo>
     {
+        public static readonly FieldPolicies Instance = new FieldPolicies();
+
+        public FieldPolicies() : base(MemberTypeIndex.Field) { }
+
         [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2070:UnrecognizedReflectionPattern",
             Justification = "Reflection implementation")]
         public sealed override IEnumerable<FieldInfo> GetDeclaredMembers(TypeInfo typeInfo)

src/coreclr/nativeaot/System.Private.CoreLib/src/System/Reflection/Runtime/BindingFlagSupport/MemberPolicies.cs

@@ -15,6 +15,11 @@ namespace System.Reflection.Runtime.BindingFlagSupport
     //=================================================================================================================
     internal abstract class MemberPolicies<M> where M : MemberInfo
     {
+        public MemberPolicies(int index)
+        {
+            Index = index;
+        }
+
         //=================================================================================================================
         // Subclasses for specific MemberInfo types must override these:
         //=================================================================================================================
@@ -184,55 +189,11 @@ private static bool GenericMethodAwareAreParameterTypesEqual(Type t1, Type t2)
             return false;
         }
 
-        static MemberPolicies()
-        {
-            Type t = typeof(M);
-            if (t.Equals(typeof(FieldInfo)))
-            {
-                MemberTypeIndex = BindingFlagSupport.MemberTypeIndex.Field;
-                Default = (MemberPolicies<M>)(object)(new FieldPolicies());
-            }
-            else if (t.Equals(typeof(MethodInfo)))
-            {
-                MemberTypeIndex = BindingFlagSupport.MemberTypeIndex.Method;
-                Default = (MemberPolicies<M>)(object)(new MethodPolicies());
-            }
-            else if (t.Equals(typeof(ConstructorInfo)))
-            {
-                MemberTypeIndex = BindingFlagSupport.MemberTypeIndex.Constructor;
-                Default = (MemberPolicies<M>)(object)(new ConstructorPolicies());
-            }
-            else if (t.Equals(typeof(PropertyInfo)))
-            {
-                MemberTypeIndex = BindingFlagSupport.MemberTypeIndex.Property; ;
-                Default = (MemberPolicies<M>)(object)(new PropertyPolicies());
-            }
-            else if (t.Equals(typeof(EventInfo)))
-            {
-                MemberTypeIndex = BindingFlagSupport.MemberTypeIndex.Event;
-                Default = (MemberPolicies<M>)(object)(new EventPolicies());
-            }
-            else if (t.Equals(typeof(Type)))
-            {
-                MemberTypeIndex = BindingFlagSupport.MemberTypeIndex.NestedType;
-                Default = (MemberPolicies<M>)(object)(new NestedTypePolicies());
-            }
-            else
-            {
-                Debug.Fail("Unknown MemberInfo type.");
-            }
-        }
-
-        //
-        // This is a singleton class one for each MemberInfo category: Return the appropriate one.
-        //
-        public static readonly MemberPolicies<M> Default;
-
         //
         // This returns a fixed value from 0 to MemberIndex.Count-1 with each possible type of M
         // being assigned a unique index (see the MemberTypeIndex for possible values). This is useful
         // for converting a type reference to M to an array index or switch case label.
         //
-        public static readonly int MemberTypeIndex;
+        public int Index { get; }
     }
 }

src/coreclr/nativeaot/System.Private.CoreLib/src/System/Reflection/Runtime/BindingFlagSupport/MethodPolicies.cs

@@ -13,6 +13,10 @@ namespace System.Reflection.Runtime.BindingFlagSupport
     //==========================================================================================================================
     internal sealed class MethodPolicies : MemberPolicies<MethodInfo>
     {
+        public static readonly MethodPolicies Instance = new MethodPolicies();
+
+        public MethodPolicies() : base(MemberTypeIndex.Method) { }
+
         [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2070:UnrecognizedReflectionPattern",
             Justification = "Reflection implementation")]
         public sealed override IEnumerable<MethodInfo> GetDeclaredMembers(TypeInfo typeInfo)

src/coreclr/nativeaot/System.Private.CoreLib/src/System/Reflection/Runtime/BindingFlagSupport/NestedTypePolicies.cs

@@ -23,6 +23,10 @@ namespace System.Reflection.Runtime.BindingFlagSupport
     //==========================================================================================================================
     internal sealed class NestedTypePolicies : MemberPolicies<Type>
     {
+        public static readonly NestedTypePolicies Instance = new NestedTypePolicies();
+
+        public NestedTypePolicies() : base(MemberTypeIndex.NestedType) { }
+
         [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2070:UnrecognizedReflectionPattern",
             Justification = "Reflection implementation")]
         public sealed override IEnumerable<Type> GetDeclaredMembers(TypeInfo typeInfo)

src/coreclr/nativeaot/System.Private.CoreLib/src/System/Reflection/Runtime/BindingFlagSupport/PropertyPolicies.cs

@@ -13,6 +13,10 @@ namespace System.Reflection.Runtime.BindingFlagSupport
     //==========================================================================================================================
     internal sealed class PropertyPolicies : MemberPolicies<PropertyInfo>
     {
+        public static readonly PropertyPolicies Instance = new PropertyPolicies();
+
+        public PropertyPolicies() : base(MemberTypeIndex.Property) { }
+
         [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2070:UnrecognizedReflectionPattern",
             Justification = "Reflection implementation")]
         public sealed override IEnumerable<PropertyInfo> GetDeclaredMembers(TypeInfo typeInfo)
@@ -54,7 +58,7 @@ public sealed override bool ImplicitlyOverrides(PropertyInfo? baseMember, Proper
         {
             MethodInfo? baseAccessor = GetAccessorMethod(baseMember!);
             MethodInfo? derivedAccessor = GetAccessorMethod(derivedMember!);
-            return MemberPolicies<MethodInfo>.Default.ImplicitlyOverrides(baseAccessor, derivedAccessor);
+            return MethodPolicies.Instance.ImplicitlyOverrides(baseAccessor, derivedAccessor);
         }
 
         //

src/coreclr/nativeaot/System.Private.CoreLib/src/System/Reflection/Runtime/BindingFlagSupport/QueriedMemberList.cs

@@ -96,12 +96,10 @@ public QueriedMemberList<M> Filter(Func<M, bool> predicate)
         //
         // Filter by name and visibility from the ReflectedType.
         //
-        public static QueriedMemberList<M> Create(RuntimeTypeInfo type, string optionalNameFilter, bool ignoreCase)
+        public static QueriedMemberList<M> Create(MemberPolicies<M> policies, RuntimeTypeInfo type, string optionalNameFilter, bool ignoreCase)
         {
             RuntimeTypeInfo reflectedType = type;
 
-            MemberPolicies<M> policies = MemberPolicies<M>.Default;
-
             NameFilter? nameFilter;
             if (optionalNameFilter == null)
                 nameFilter = null;

src/coreclr/nativeaot/System.Private.CoreLib/src/System/Reflection/Runtime/BindingFlagSupport/QueryResult.cs

@@ -14,8 +14,9 @@ namespace System.Reflection.Runtime.BindingFlagSupport
     //
     internal partial struct QueryResult<M> where M : MemberInfo
     {
-        public QueryResult(BindingFlags bindingAttr, QueriedMemberList<M> queriedMembers)
+        public QueryResult(MemberPolicies<M> policies, BindingFlags bindingAttr, QueriedMemberList<M> queriedMembers)
         {
+            _policies = policies;
             _lazyCount = 0;
             _bindingAttr = bindingAttr;
             _queriedMembers = queriedMembers;
@@ -114,8 +115,7 @@ public void CopyTo(MemberInfo[] array, int startIndex)
                         if (match.DeclaringType.Equals(challenger.DeclaringType))
                             throw new AmbiguousMatchException();
 
-                        MemberPolicies<M> policies = MemberPolicies<M>.Default;
-                        if (!policies.OkToIgnoreAmbiguity(match, challenger))
+                        if (!_policies.OkToIgnoreAmbiguity(match, challenger))
                             throw new AmbiguousMatchException();
                     }
                     else
@@ -129,6 +129,7 @@ public void CopyTo(MemberInfo[] array, int startIndex)
 
         private int UnfilteredCount => ((_bindingAttr & BindingFlags.DeclaredOnly) != 0) ? _queriedMembers.DeclaredOnlyCount : _queriedMembers.TotalCount;
 
+        private readonly MemberPolicies<M> _policies;
         private readonly BindingFlags _bindingAttr;
         private int _lazyCount; // Intentionally not marking as volatile. QueryResult is for short-term use within a single method call - no aspiration to be thread-safe.
         private QueriedMemberList<M> _queriedMembers;

src/coreclr/nativeaot/System.Private.CoreLib/src/System/Reflection/Runtime/BindingFlagSupport/Shared.cs

@@ -146,9 +146,8 @@ public static bool QualifiesBasedOnParameterCount(this MethodBase methodBase, Bi
         // - MethodImpls ignored. (I didn't say it made sense, this is just how the desktop api we're porting behaves.)
         // - Implemented interfaces ignores. (I didn't say it made sense, this is just how the desktop api we're porting behaves.)
         //
-        public static M GetImplicitlyOverriddenBaseClassMember<M>(this M member) where M : MemberInfo
+        public static M GetImplicitlyOverriddenBaseClassMember<M>(this M member, MemberPolicies<M> policies) where M : MemberInfo
         {
-            MemberPolicies<M> policies = MemberPolicies<M>.Default;
             bool isVirtual;
             bool isNewSlot;
             policies.GetMemberAttributes(member, out _, out _, out isVirtual, out isNewSlot);

src/coreclr/nativeaot/System.Private.CoreLib/src/System/Reflection/Runtime/General/ReflectionCoreCallbacksImplementation.cs

@@ -146,17 +146,17 @@ public sealed override FieldInfo GetFieldFromHandle(RuntimeFieldHandle runtimeFi
 
         public sealed override EventInfo GetImplicitlyOverriddenBaseClassEvent(EventInfo e)
         {
-            return e.GetImplicitlyOverriddenBaseClassMember();
+            return e.GetImplicitlyOverriddenBaseClassMember(EventPolicies.Instance);
         }
 
         public sealed override MethodInfo GetImplicitlyOverriddenBaseClassMethod(MethodInfo m)
         {
-            return m.GetImplicitlyOverriddenBaseClassMember();
+            return m.GetImplicitlyOverriddenBaseClassMember(MethodPolicies.Instance);
         }
 
         public sealed override PropertyInfo GetImplicitlyOverriddenBaseClassProperty(PropertyInfo p)
         {
-            return p.GetImplicitlyOverriddenBaseClassMember();
+            return p.GetImplicitlyOverriddenBaseClassMember(PropertyPolicies.Instance);
         }
 
         private static FieldInfo GetFieldInfo(RuntimeTypeHandle declaringTypeHandle, FieldHandle fieldHandle)

src/coreclr/nativeaot/System.Private.CoreLib/src/System/Reflection/Runtime/MethodInfos/RuntimeMethodInfo.cs

@@ -118,7 +118,7 @@ public sealed override MethodInfo GetBaseDefinition()
 
             while (true)
             {
-                MethodInfo next = method.GetImplicitlyOverriddenBaseClassMember();
+                MethodInfo next = method.GetImplicitlyOverriddenBaseClassMember(MethodPolicies.Instance);
                 if (next == null)
                     return ((RuntimeMethodInfo)method).WithReflectedTypeSetToDeclaringType;