Clean up object pools and improve PooledHashSet<T> (#12406)

This represents some clean-up and a small performance improvement that
I've intended to do for a long while. In fact, it's been sitting on my
machine across a handful of branches for months. So, I decided to bring
it together and submit a PR.

Key Changes:
- The custom pool classes are now instance classes rather than static
classes. So, it's not possible to create an instance of an
`ArrayBuilderPool<T>` rather than an
`ObjectPool<ImmutableArray<T>.Builder>`.
- Introduce a `SpecializedPools` static class that pulls together
`StringHashSetPool`, `StringDictionaryPool<TValue>`, and
`ReferenceEqualityHashSetPool<T>`.
- Add `MaximumObjectSize` as a knob when creating new custom pools to
avoid _always_ having to create a new `IPooledObjectPolicy<T>`
implementation.
- Introduce an `IPoolableObject` interface and way to create pools of
`IPoolableObjects`.
- Improve `PooledHashSet<T>` to avoid acquiring a `HashSet<T>` from a
pool until there are at least two items.

----
CI Build:
https://dev.azure.com/dnceng/internal/_build/results?buildId=2826683&view=results
Test Insertion:
https://dev.azure.com/devdiv/DevDiv/_git/VS/pullrequest/684259
Toolset Run:
https://dev.azure.com/dnceng/internal/_build/results?buildId=2826684&view=results

Author: DustinCampbell

SpellingExclusions.dic

@@ -7,3 +7,4 @@ microsoft
 vsls
 Blazor
 Metacode
+Poolable

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/CSharp/ComponentTagHelperDescriptorProvider.cs

@@ -125,7 +125,7 @@ private static TagHelperDescriptor CreateNameMatchingDescriptor(
             {
                 metadata.IsGeneric = true;
 
-                using var cascadeGenericTypeAttributes = new PooledHashSet<string>(StringHashSetPool.Ordinal);
+                using var cascadeGenericTypeAttributes = new PooledHashSet<string>(StringComparer.Ordinal);
 
                 foreach (var attribute in type.GetAttributes())
                 {
@@ -610,7 +610,7 @@ private static void CreateContextParameter(TagHelperDescriptorBuilder builder, s
         // - are not indexers
         private static ImmutableArray<(IPropertySymbol property, PropertyKind kind)> GetProperties(INamedTypeSymbol type)
         {
-            using var names = new PooledHashSet<string>(StringHashSetPool.Ordinal);
+            using var names = new PooledHashSet<string>(StringComparer.Ordinal);
             using var results = new PooledArrayBuilder<(IPropertySymbol, PropertyKind)>();
 
             var currentType = type;

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/CSharp/DefaultTagHelperDescriptorFactory.cs

@@ -375,7 +375,7 @@ private static bool IsPotentialDictionaryProperty(IPropertySymbol property)
     private static void CollectAccessibleProperties(
         INamedTypeSymbol typeSymbol, ref PooledArrayBuilder<IPropertySymbol> properties)
     {
-        using var names = new PooledHashSet<string>(StringHashSetPool.Ordinal);
+        using var names = new PooledHashSet<string>(StringComparer.Ordinal);
 
         // Traverse the type hierarchy to find all accessible properties.
         var currentType = typeSymbol;

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/AllowedChildTagDescriptorBuilder_Pooling.cs

@@ -8,7 +8,8 @@ namespace Microsoft.AspNetCore.Razor.Language;
 
 public partial class AllowedChildTagDescriptorBuilder
 {
-    internal static readonly ObjectPool<AllowedChildTagDescriptorBuilder> Pool = DefaultPool.Create(Policy.Instance);
+    internal static readonly ObjectPool<AllowedChildTagDescriptorBuilder> Pool =
+        DefaultPool.Create(static () => new AllowedChildTagDescriptorBuilder());
 
     internal static AllowedChildTagDescriptorBuilder GetInstance(TagHelperDescriptorBuilder parent)
     {
@@ -26,15 +27,4 @@ private protected override void Reset()
         Name = null;
         DisplayName = null;
     }
-
-    private sealed class Policy : PooledBuilderPolicy<AllowedChildTagDescriptorBuilder>
-    {
-        public static readonly Policy Instance = new();
-
-        private Policy()
-        {
-        }
-
-        public override AllowedChildTagDescriptorBuilder Create() => new();
-    }
 }

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/BoundAttributeDescriptorBuilder_Pooling.cs

@@ -8,7 +8,8 @@ namespace Microsoft.AspNetCore.Razor.Language;
 
 public partial class BoundAttributeDescriptorBuilder
 {
-    internal static readonly ObjectPool<BoundAttributeDescriptorBuilder> Pool = DefaultPool.Create(Policy.Instance);
+    internal static readonly ObjectPool<BoundAttributeDescriptorBuilder> Pool =
+        DefaultPool.Create(static () => new BoundAttributeDescriptorBuilder());
 
     internal static BoundAttributeDescriptorBuilder GetInstance(TagHelperDescriptorBuilder parent)
     {
@@ -36,15 +37,4 @@ private protected override void Reset()
         ContainingType = null;
         Parameters.Clear();
     }
-
-    private sealed class Policy : PooledBuilderPolicy<BoundAttributeDescriptorBuilder>
-    {
-        public static readonly Policy Instance = new();
-
-        private Policy()
-        {
-        }
-
-        public override BoundAttributeDescriptorBuilder Create() => new();
-    }
 }

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/BoundAttributeParameterDescriptorBuilder_Pooling.cs

@@ -8,7 +8,8 @@ namespace Microsoft.AspNetCore.Razor.Language;
 
 public partial class BoundAttributeParameterDescriptorBuilder
 {
-    internal static readonly ObjectPool<BoundAttributeParameterDescriptorBuilder> Pool = DefaultPool.Create(Policy.Instance);
+    internal static readonly ObjectPool<BoundAttributeParameterDescriptorBuilder> Pool =
+        DefaultPool.Create(static () => new BoundAttributeParameterDescriptorBuilder());
 
     internal static BoundAttributeParameterDescriptorBuilder GetInstance(BoundAttributeDescriptorBuilder parent)
     {
@@ -29,15 +30,4 @@ private protected override void Reset()
         Name = null;
         PropertyName = null;
     }
-
-    private sealed class Policy : PooledBuilderPolicy<BoundAttributeParameterDescriptorBuilder>
-    {
-        public static readonly Policy Instance = new();
-
-        private Policy()
-        {
-        }
-
-        public override BoundAttributeParameterDescriptorBuilder Create() => new();
-    }
 }

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Components/ComponentBindLoweringPass.cs

@@ -217,7 +217,7 @@ private static void ProcessDuplicates(
         ref PooledArrayBuilder<IntermediateNodeReference<TagHelperDirectiveAttributeIntermediateNode>> references,
         ref PooledArrayBuilder<IntermediateNodeReference<TagHelperDirectiveAttributeParameterIntermediateNode>> parameterReferences)
     {
-        using var _ = ReferenceEqualityHashSetPool<IntermediateNode>.GetPooledObject(out var parents);
+        using var _ = SpecializedPools.GetPooledReferenceEqualityHashSet<IntermediateNode>(out var parents);
 
         foreach (var reference in references)
         {
@@ -307,7 +307,7 @@ private static void ProcessDuplicateAttributes(IntermediateNode node)
         // If we still have duplicates at this point then they are genuine conflicts.
         // Use a hash set to quickly determine whether there are any duplicates.
         // If so, we need to do a more expensive pass to identify and remove them.
-        using var _ = StringHashSetPool.Ordinal.GetPooledObject(out var duplicates);
+        using var _ = SpecializedPools.GetPooledStringHashSet(out var duplicates);
 
         foreach (var child in children)
         {
@@ -329,7 +329,7 @@ static void ReportDiagnosticAndRemoveDuplicates(IntermediateNode node)
         {
             var children = node.Children;
 
-            using var _ = StringDictionaryPool<ImmutableArray<AttributeInfo>.Builder>.Ordinal.GetPooledObject(out var duplicates);
+            using var _ = SpecializedPools.GetPooledStringDictionary<ImmutableArray<AttributeInfo>.Builder>(out var duplicates);
 
             for (var i = 0; i < children.Count; i++)
             {

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Components/ComponentEventHandlerLoweringPass.cs

@@ -36,7 +36,7 @@ protected override void ExecuteCore(
         // For each event handler *usage* we need to rewrite the tag helper node to map to basic constructs.
         // Each usage will be represented by a tag helper property that is a descendant of either
         // a component or element.
-        using var _ = ReferenceEqualityHashSetPool<IntermediateNode>.GetPooledObject(out var parents);
+        using var _ = SpecializedPools.GetPooledReferenceEqualityHashSet<IntermediateNode>(out var parents);
         var references = documentNode.FindDescendantReferences<TagHelperDirectiveAttributeIntermediateNode>();
 
         foreach (var reference in references)

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/DefaultRazorIntermediateNodeLoweringPhase.cs

@@ -187,7 +187,7 @@ private static IReadOnlyList<UsingReference> ImportDirectives(
 
     private static void PostProcessImportedDirectives(DocumentIntermediateNode document)
     {
-        using var _ = ReferenceEqualityHashSetPool<DirectiveDescriptor>.GetPooledObject(out var seenDirectives);
+        using var _ = SpecializedPools.GetPooledReferenceEqualityHashSet<DirectiveDescriptor>(out var seenDirectives);
         var references = document.FindDescendantReferences<DirectiveIntermediateNode>();
 
         for (var i = references.Length - 1; i >= 0; i--)

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/DefaultRazorTagHelperContextDiscoveryPhase.cs

@@ -12,7 +12,6 @@
 using Microsoft.AspNetCore.Razor.Language.Legacy;
 using Microsoft.AspNetCore.Razor.Language.Syntax;
 using Microsoft.AspNetCore.Razor.PooledObjects;
-using Microsoft.Extensions.ObjectPool;
 
 namespace Microsoft.AspNetCore.Razor.Language;
 
@@ -73,7 +72,7 @@ internal static ReadOnlyMemory<char> GetMemoryWithoutGlobalPrefix(string s)
         return mem;
     }
 
-    internal abstract class DirectiveVisitor : SyntaxWalker
+    internal abstract class DirectiveVisitor : SyntaxWalker, IPoolableObject
     {
         private bool _isInitialized;
         private string? _filePath;
@@ -173,7 +172,7 @@ internal sealed class TagHelperDirectiveVisitor : DirectiveVisitor
         /// A larger pool of <see cref="TagHelperDescriptor"/> lists to handle scenarios where tag helpers
         /// originate from a large number of assemblies.
         /// </summary>
-        private static readonly ObjectPool<List<TagHelperDescriptor>> s_pool = ListPool<TagHelperDescriptor>.Create(100);
+        private static readonly ListPool<TagHelperDescriptor> s_pool = ListPool<TagHelperDescriptor>.Create(poolSize: 100);
 
         /// <summary>
         /// A map from assembly name to list of <see cref="TagHelperDescriptor"/>. Lists are allocated from and returned to