Improve performance and memory usage of TagHelperBinder

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/DefaultRazorTagHelperBinderPhaseTest.cs

@@ -295,7 +295,7 @@ public void Execute_DirectiveWithoutQuotes_RewritesTagHelpers_TagHelperMatchesEl
 
         var formTagHelper = Assert.Single(tagHelperNodes);
         Assert.Equal("form", formTagHelper.TagHelperInfo.TagName);
-        Assert.Equal(2, formTagHelper.TagHelperInfo.BindingResult.Mappings[tagHelper].Length);
+        Assert.Equal(2, formTagHelper.TagHelperInfo.BindingResult.GetBoundRules(tagHelper).Length);
     }
 
     [Fact]
@@ -340,7 +340,7 @@ public void Execute_DirectiveWithQuotes_RewritesTagHelpers_TagHelperMatchesEleme
 
         var formTagHelper = Assert.Single(tagHelperNodes);
         Assert.Equal("form", formTagHelper.TagHelperInfo.TagName);
-        Assert.Equal(2, formTagHelper.TagHelperInfo.BindingResult.Mappings[tagHelper].Length);
+        Assert.Equal(2, formTagHelper.TagHelperInfo.BindingResult.GetBoundRules(tagHelper).Length);
     }
 
     [Fact]
@@ -441,6 +441,7 @@ public void Execute_SetsTagHelperDocumentContext()
 
         // Assert
         var context = codeDocument.GetTagHelperContext();
+        Assert.NotNull(context);
         Assert.Null(context.Prefix);
         Assert.Empty(context.TagHelpers);
     }

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/ComponentDiscoveryIntegrationTest.cs

@@ -32,8 +32,9 @@ public class MyComponent : ComponentBase
         var result = CompileToCSharp(string.Empty);
 
         // Assert
-        var bindings = result.CodeDocument.GetTagHelperContext();
-        Assert.Contains(bindings.TagHelpers, t => t.Name == "Test.MyComponent");
+        var context = result.CodeDocument.GetTagHelperContext();
+        Assert.NotNull(context);
+        Assert.Contains(context.TagHelpers, t => t.Name == "Test.MyComponent");
     }
 
     [Fact]
@@ -55,15 +56,16 @@ public class MyComponent : ComponentBase
         var result = CompileToCSharp(string.Empty);
 
         // Assert
-        var bindings = result.CodeDocument.GetTagHelperContext();
+        var context = result.CodeDocument.GetTagHelperContext();
+        Assert.NotNull(context);
 
-        Assert.Contains(bindings.TagHelpers, t =>
+        Assert.Contains(context.TagHelpers, t =>
         {
             return t.Name == "Test.AnotherNamespace.MyComponent" &&
                 t.IsComponentFullyQualifiedNameMatch;
         });
 
-        Assert.DoesNotContain(bindings.TagHelpers, t =>
+        Assert.DoesNotContain(context.TagHelpers, t =>
         {
             return t.Name == "Test.AnotherNamespace.MyComponent" &&
                 !t.IsComponentFullyQualifiedNameMatch;
@@ -79,8 +81,10 @@ public void ComponentDiscovery_CanFindComponent_DefinedinCshtml()
         var result = CompileToCSharp("UniqueName.cshtml", cshtmlContent: string.Empty);
 
         // Assert
-        var bindings = result.CodeDocument.GetTagHelperContext();
-        Assert.Contains(bindings.TagHelpers, t => t.Name == "Test.UniqueName");
+        var context = result.CodeDocument.GetTagHelperContext();
+        Assert.NotNull(context);
+
+        Assert.Contains(context.TagHelpers, t => t.Name == "Test.UniqueName");
     }
 
     [Fact]
@@ -96,8 +100,10 @@ @typeparam TItem
 }");
 
         // Assert
-        var bindings = result.CodeDocument.GetTagHelperContext();
-        Assert.Contains(bindings.TagHelpers, t => t.Name == "Test.UniqueName<TItem>");
+        var context = result.CodeDocument.GetTagHelperContext();
+        Assert.NotNull(context);
+
+        Assert.Contains(context.TagHelpers, t => t.Name == "Test.UniqueName<TItem>");
     }
 
     [Fact]
@@ -113,8 +119,10 @@ public void ComponentDiscovery_CanFindComponent_WithTypeParameterAndSemicolon()
 }");
 
         // Assert
-        var bindings = result.CodeDocument.GetTagHelperContext();
-        Assert.Contains(bindings.TagHelpers, t => t.Name == "Test.UniqueName<TItem>");
+        var context = result.CodeDocument.GetTagHelperContext();
+        Assert.NotNull(context);
+
+        Assert.Contains(context.TagHelpers, t => t.Name == "Test.UniqueName<TItem>");
     }
 
     [Fact]
@@ -132,8 +140,10 @@ @typeparam TItem3
 }");
 
         // Assert
-        var bindings = result.CodeDocument.GetTagHelperContext();
-        Assert.Contains(bindings.TagHelpers, t => t.Name == "Test.UniqueName<TItem1, TItem2, TItem3>");
+        var context = result.CodeDocument.GetTagHelperContext();
+        Assert.NotNull(context);
+
+        Assert.Contains(context.TagHelpers, t => t.Name == "Test.UniqueName<TItem1, TItem2, TItem3>");
     }
 
     [Fact]
@@ -151,7 +161,9 @@ @typeparam TItem3
 }");
 
         // Assert
-        var bindings = result.CodeDocument.GetTagHelperContext();
-        Assert.Contains(bindings.TagHelpers, t => t.Name == "Test.UniqueName<TItem1, TItem2, TItem3>");
+        var context = result.CodeDocument.GetTagHelperContext();
+        Assert.NotNull(context);
+
+        Assert.Contains(context.TagHelpers, t => t.Name == "Test.UniqueName<TItem1, TItem2, TItem3>");
     }
 }

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/RazorCodeDocumentExtensionsTest.cs

@@ -137,13 +137,13 @@ public void SetCSharpDocument_SetsCSharpDocument()
     }
 
     [Fact]
-    public void GetTagHelperContext_ReturnsTagHelperContext()
+    public void GetAndSetTagHelperContext_ReturnsTagHelperContext()
     {
         // Arrange
         var codeDocument = TestRazorCodeDocument.CreateEmpty();
 
         var expected = TagHelperDocumentContext.Create(prefix: null, tagHelpers: []);
-        codeDocument.Items[typeof(TagHelperDocumentContext)] = expected;
+        codeDocument.SetTagHelperContext(expected);
 
         // Act
         var actual = codeDocument.GetTagHelperContext();
@@ -152,21 +152,6 @@ public void GetTagHelperContext_ReturnsTagHelperContext()
         Assert.Same(expected, actual);
     }
 
-    [Fact]
-    public void SetTagHelperContext_SetsTagHelperContext()
-    {
-        // Arrange
-        var codeDocument = TestRazorCodeDocument.CreateEmpty();
-
-        var expected = TagHelperDocumentContext.Create(prefix: null, tagHelpers: []);
-
-        // Act
-        codeDocument.SetTagHelperContext(expected);
-
-        // Assert
-        Assert.Same(expected, codeDocument.Items[typeof(TagHelperDocumentContext)]);
-    }
-
     [Fact]
     public void TryComputeNamespace_RootNamespaceNotSet_ReturnsNull()
     {

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TagHelperBinderTest.cs

@@ -38,8 +38,8 @@ public void GetBinding_ReturnsBindingWithInformation()
         Assert.Equal("th:div", bindingResult.TagName);
         Assert.Equal("body", bindingResult.ParentTagName);
         Assert.Equal<KeyValuePair<string, string>>(expectedAttributes, bindingResult.Attributes);
-        Assert.Equal("th:", bindingResult.TagHelperPrefix);
-        Assert.Equal<TagMatchingRuleDescriptor>(divTagHelper.TagMatchingRules, bindingResult.Mappings[divTagHelper]);
+        Assert.Equal("th:", bindingResult.TagNamePrefix);
+        Assert.Equal<TagMatchingRuleDescriptor>(divTagHelper.TagMatchingRules, bindingResult.GetBoundRules(divTagHelper));
     }
 
     [Fact]
@@ -81,7 +81,7 @@ void TestTagName(string tagName, TagMatchingRuleDescriptor expectedBindingResult
                 Assert.Equal<TagHelperDescriptor>(expectedDescriptors, bindingResult.Descriptors);
 
                 Assert.Equal(tagName, bindingResult.TagName);
-                var mapping = Assert.Single(bindingResult.Mappings[multiTagHelper]);
+                var mapping = Assert.Single(bindingResult.GetBoundRules(multiTagHelper));
                 Assert.Equal(expectedBindingResult, mapping);
             }
         }
@@ -136,7 +136,7 @@ void TestTagName(string tagName, TagHelperDescriptor[] expectedDescriptors, TagM
 
                 for (int i = 0; i < expectedDescriptors.Length; i++)
                 {
-                    var mapping = Assert.Single(bindingResult.Mappings[expectedDescriptors[i]]);
+                    var mapping = Assert.Single(bindingResult.GetBoundRules(expectedDescriptors[i]));
                     Assert.Equal(expectedBindingResults[i], mapping);
                 }
             }
@@ -598,7 +598,7 @@ public void GetBinding_DescriptorWithMultipleRules_CorrectlySelectsMatchingRules
         // Assert
         var boundDescriptor = Assert.Single(binding.Descriptors);
         Assert.Same(multiRuleDescriptor, boundDescriptor);
-        var boundRules = binding.Mappings[boundDescriptor];
+        var boundRules = binding.GetBoundRules(boundDescriptor);
         var boundRule = Assert.Single(boundRules);
         Assert.Equal("div", boundRule.TagName);
     }
@@ -626,7 +626,7 @@ public void GetBinding_PrefixedParent_ReturnsBinding()
         // Assert
         var boundDescriptor = Assert.Single(bindingResult.Descriptors);
         Assert.Same(divDescriptor, boundDescriptor);
-        var boundRules = bindingResult.Mappings[boundDescriptor];
+        var boundRules = bindingResult.GetBoundRules(boundDescriptor);
         var boundRule = Assert.Single(boundRules);
         Assert.Equal("div", boundRule.TagName);
         Assert.Equal("p", boundRule.ParentTag);

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

@@ -12,7 +12,7 @@ protected override void ExecuteCore(RazorCodeDocument codeDocument, Cancellation
     {
         var syntaxTree = codeDocument.GetPreTagHelperSyntaxTree();
         var context = codeDocument.GetTagHelperContext();
-        if (syntaxTree is null || context.TagHelpers.Length == 0)
+        if (syntaxTree is null || context is not { TagHelpers.Length: > 0 })
         {
             // No descriptors, no-op.
             return;

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Legacy/TagHelperBlockRewriter.cs

@@ -27,10 +27,9 @@ public static TagMode GetTagMode(
         }
 
         var hasDirectiveAttribute = false;
-        foreach (var descriptor in bindingResult.Descriptors)
+        foreach (var boundRulesInfo in bindingResult.AllBoundRules)
         {
-            var boundRules = bindingResult.Mappings[descriptor];
-            var nonDefaultRule = boundRules.FirstOrDefault(static rule => rule.TagStructure != TagStructure.Unspecified);
+            var nonDefaultRule = boundRulesInfo.Rules.FirstOrDefault(static rule => rule.TagStructure != TagStructure.Unspecified);
 
             if (nonDefaultRule?.TagStructure == TagStructure.WithoutEndTag)
             {
@@ -42,6 +41,7 @@ public static TagMode GetTagMode(
             // <input @onclick="..."> vs <input onclick="..." />
             //
             // We don't want this to become an error just because you added a directive attribute.
+            var descriptor = boundRulesInfo.Descriptor;
             if (descriptor.IsAnyComponentDocumentTagHelper() && !descriptor.IsComponentOrChildContentTagHelper)
             {
                 hasDirectiveAttribute = true;

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Legacy/TagHelperParseTreeRewriter.cs

@@ -34,9 +34,9 @@ public static RazorSyntaxTree Rewrite(RazorSyntaxTree syntaxTree, TagHelperBinde
         builder.AddRange(treeDiagnostics);
         builder.AddRange(sinkDiagnostics);
 
-        foreach (var tagHelper in binder.TagHelpers)
+        foreach (var descriptor in binder.Descriptors)
         {
-            foreach (var diagnostic in tagHelper.GetAllDiagnostics())
+            foreach (var diagnostic in descriptor.GetAllDiagnostics())
             {
                 builder.Add(diagnostic);
             }
@@ -137,7 +137,7 @@ public override SyntaxNode VisitMarkupElement(MarkupElementSyntax node)
                     else
                     {
                         // Tag helper start tag. Keep track.
-                        var tracker = new TagHelperTracker(_binder.TagHelperPrefix, tagHelperInfo);
+                        var tracker = new TagHelperTracker(_binder.TagNamePrefix, tagHelperInfo);
                         _trackerStack.Push(tracker);
                     }
                 }
@@ -347,10 +347,9 @@ private bool TryRewriteTagHelperEnd(
                     return false;
                 }
 
-                foreach (var descriptor in tagHelperBinding.Descriptors)
+                foreach (var boundRulesInfo in tagHelperBinding.AllBoundRules)
                 {
-                    var boundRules = tagHelperBinding.Mappings[descriptor];
-                    var invalidRule = boundRules.FirstOrDefault(static rule => rule.TagStructure == TagStructure.WithoutEndTag);
+                    var invalidRule = boundRulesInfo.Rules.FirstOrDefault(static rule => rule.TagStructure == TagStructure.WithoutEndTag);
 
                     if (invalidRule != null)
                     {
@@ -359,7 +358,7 @@ private bool TryRewriteTagHelperEnd(
                             RazorDiagnosticFactory.CreateParsing_TagHelperMustNotHaveAnEndTag(
                                 new SourceSpan(SourceLocationTracker.Advance(endTag.GetSourceLocation(_source), "</"), tagName.Length),
                                 tagName,
-                                descriptor.DisplayName,
+                                boundRulesInfo.Descriptor.DisplayName,
                                 invalidRule.TagStructure));
 
                         return false;
@@ -462,10 +461,11 @@ private void ValidateBinding(
             TagHelperDescriptor? baseDescriptor = null;
             TagStructure? baseStructure = null;
 
-            foreach (var descriptor in bindingResult.Descriptors)
+            foreach (var boundRulesInfo in bindingResult.AllBoundRules)
             {
-                var boundRules = bindingResult.Mappings[descriptor];
-                foreach (var rule in boundRules)
+                var descriptor = boundRulesInfo.Descriptor;
+
+                foreach (var rule in boundRulesInfo.Rules)
                 {
                     if (rule.TagStructure != TagStructure.Unspecified)
                     {
@@ -726,18 +726,18 @@ private record TagHelperTracker : TagTracker
         {
             public uint OpenMatchingTags;
 
-            private readonly string? _tagHelperPrefix;
+            private readonly string? _tagNamePrefix;
             private readonly TagHelperBinding _binding;
 
             private readonly Lazy<(ImmutableArray<string> Names, HashSet<string> NameSet)> _lazyAllowedChildren;
             private readonly Lazy<HashSet<string>> _lazyPrefixedAllowedChildrenNameSet;
 
             public ImmutableArray<string> AllowedChildren => _lazyAllowedChildren.Value.Names;
 
-            public TagHelperTracker(string? tagHelperPrefix, TagHelperInfo info)
+            public TagHelperTracker(string? tagNamePrefix, TagHelperInfo info)
                 : base(info.TagName, IsTagHelper: true)
             {
-                _tagHelperPrefix = tagHelperPrefix;
+                _tagNamePrefix = tagNamePrefix;
                 _binding = info.BindingResult;
 
                 _lazyAllowedChildren = new(CreateAllowedChildren);
@@ -773,7 +773,7 @@ public bool AllowsChild(string tagName, bool nameIncludesPrefix)
 
             private HashSet<string> CreatePrefixedAllowedChildren()
             {
-                if (_tagHelperPrefix is not string tagHelperPrefix)
+                if (_tagNamePrefix is not string tagNamePrefix)
                 {
                     return _lazyAllowedChildren.Value.NameSet;
                 }
@@ -782,7 +782,7 @@ private HashSet<string> CreatePrefixedAllowedChildren()
 
                 foreach (var childName in AllowedChildren)
                 {
-                    distinctSet.Add(tagHelperPrefix + childName);
+                    distinctSet.Add(tagNamePrefix + childName);
                 }
 
                 return distinctSet;

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

@@ -2,6 +2,8 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Collections.Immutable;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using Microsoft.CodeAnalysis;
 
 namespace Microsoft.AspNetCore.Razor.Language;
@@ -17,6 +19,8 @@ public sealed class RazorCodeDocument
 
     public string FileKind => ParserOptions.FileKind;
 
+    private TagHelperDocumentContext? _tagHelperContext;
+
     private RazorCodeDocument(
         RazorSourceDocument source,
         ImmutableArray<RazorSourceDocument> imports,
@@ -52,4 +56,23 @@ public static RazorCodeDocument Create(
 
         return new RazorCodeDocument(source, imports, parserOptions, codeGenerationOptions);
     }
+
+    internal bool TryGetTagHelperContext([NotNullWhen(true)] out TagHelperDocumentContext? result)
+    {
+        result = _tagHelperContext;
+        return result is not null;
+    }
+
+    internal TagHelperDocumentContext? GetTagHelperContext()
+        => _tagHelperContext;
+
+    internal TagHelperDocumentContext GetRequiredTagHelperContext()
+        => _tagHelperContext.AssumeNotNull();
+
+    internal void SetTagHelperContext(TagHelperDocumentContext context)
+    {
+        ArgHelper.ThrowIfNull(context);
+
+        _tagHelperContext = context;
+    }
 }