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PhenX merged 4 commits into from
Mar 4, 2026
Merged

Add source generator self-benchmark covering all expression transformers #168

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Add GeneratorBenchmarks: source generator self-benchmark with MemoryD…
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Expand GeneratorBenchmarks: cover all expression transformers + proje…
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Mar 4, 2026
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5 changes: 4 additions & 1 deletion ...yFrameworkCore.Projectables.Benchmarks/EntityFrameworkCore.Projectables.Benchmarks.csproj
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<ItemGroup>
<PackageReference Include="BenchmarkDotNet" />
<PackageReference Include="Microsoft.CodeAnalysis.CSharp" />
<PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" />
<PackageReference Include="Basic.Reference.Assemblies.Net80" Condition="'$(TargetFramework)' == 'net8.0'" />
<PackageReference Include="Basic.Reference.Assemblies.Net100" Condition="'$(TargetFramework)' == 'net10.0'" />
</ItemGroup>

<ItemGroup>
<ProjectReference Include="..\..\src\EntityFrameworkCore.Projectables.Generator\EntityFrameworkCore.Projectables.Generator.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
<ProjectReference Include="..\..\src\EntityFrameworkCore.Projectables.Generator\EntityFrameworkCore.Projectables.Generator.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="true" />
<ProjectReference Include="..\..\src\EntityFrameworkCore.Projectables\EntityFrameworkCore.Projectables.csproj" />
</ItemGroup>

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233 changes: 233 additions & 0 deletions benchmarks/EntityFrameworkCore.Projectables.Benchmarks/GeneratorBenchmarks.cs
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using System.Text;
using BenchmarkDotNet.Attributes;
using EntityFrameworkCore.Projectables;
using EntityFrameworkCore.Projectables.Generator;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.Text;

namespace EntityFrameworkCore.Projectables.Benchmarks;

[MemoryDiagnoser]
public class GeneratorBenchmarks
{
[Params(1, 100, 1000)]
public int ProjectableCount { get; set; }

private Compilation _compilation = null!;
private GeneratorDriver _warmedDriver = null!;
private Compilation _modifiedCompilation = null!;

[GlobalSetup]
public void Setup()
{
_compilation = CreateCompilation(ProjectableCount);

// Warm up the driver once so incremental state is established.
_warmedDriver = CSharpGeneratorDriver
.Create(new ProjectionExpressionGenerator())
.RunGeneratorsAndUpdateCompilation(_compilation, out _, out _);

// Create a slightly modified compilation that doesn't affect any
// [Projectable] members — used to exercise the incremental cache path.
var originalTree = _compilation.SyntaxTrees.First();
var originalText = originalTree.GetText().ToString();
var modifiedText = originalText + "\n// bench-edit";
var modifiedTree = originalTree.WithChangedText(SourceText.From(modifiedText));
_modifiedCompilation = _compilation.ReplaceSyntaxTree(originalTree, modifiedTree);
}

/// <summary>Cold run: a fresh driver is created every iteration.</summary>
[Benchmark]
public GeneratorDriver RunGenerator()
{
return CSharpGeneratorDriver
.Create(new ProjectionExpressionGenerator())
.RunGeneratorsAndUpdateCompilation(_compilation, out _, out _);
}

/// <summary>
/// Warm incremental run: the pre-warmed driver processes a trivial one-line
/// edit that does not touch any <c>[Projectable]</c> member, exercising the
/// incremental caching path.
/// </summary>
[Benchmark]
public GeneratorDriver RunGenerator_Incremental()
{
return _warmedDriver
.RunGeneratorsAndUpdateCompilation(_modifiedCompilation, out _, out _);
}

private static Compilation CreateCompilation(int projectableCount)
{
var source = BuildSource(projectableCount);

var references = Basic.Reference.Assemblies.
#if NET10_0
Net100
#else
Net80
#endif
.References.All.ToList();

references.Add(MetadataReference.CreateFromFile(typeof(ProjectableAttribute).Assembly.Location));

return CSharpCompilation.Create(
"GeneratorBenchmarkInput",
new[] { CSharpSyntaxTree.ParseText(source) },
references,
new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary));
}

private static string BuildSource(int projectableCount)
{
var sb = new StringBuilder();
sb.AppendLine("using System;");
sb.AppendLine("using EntityFrameworkCore.Projectables;");
sb.AppendLine();
sb.AppendLine("namespace GeneratorBenchmarkInput;");
sb.AppendLine();

// Enum used by the switch-expression and is-pattern members.
sb.AppendLine("public enum OrderStatus { Pending, Active, Completed, Cancelled }");
sb.AppendLine();

sb.AppendLine("public class Order");
sb.AppendLine("{");
sb.AppendLine(" public string FirstName { get; set; } = string.Empty;");
sb.AppendLine(" public string LastName { get; set; } = string.Empty;");
sb.AppendLine(" public string? Email { get; set; }");
sb.AppendLine(" public decimal Amount { get; set; }");
sb.AppendLine(" public decimal TaxRate { get; set; }");
sb.AppendLine(" public DateTime? DeletedAt { get; set; }");
sb.AppendLine(" public bool IsEnabled { get; set; }");
sb.AppendLine(" public int Priority { get; set; }");
sb.AppendLine(" public OrderStatus Status { get; set; }");
sb.AppendLine();

// Nine member kinds — one per transformer path in the generator:
// 0 simple string-concat property (ExpressionSyntaxRewriter baseline)
// 1 boolean null-check property (ExpressionSyntaxRewriter, logical AND)
// 2 single-param decimal method (ExpressionSyntaxRewriter, arithmetic)
// 3 multi-param string method (ExpressionSyntaxRewriter, concat)
// 4 null-conditional property (NullConditionalRewrite, Rewrite mode)
// 5 switch-expression method (SwitchExpressionRewrite, relational patterns)
// 6 is-pattern property (VisitIsPatternExpression, not-null pattern)
// 7 block-bodied if/else chain (BlockStatementConverter)
// 8 block-bodied switch with local var (BlockStatementConverter + local replacement)
for (int i = 0; i < projectableCount; i++)
{
switch (i % 9)
{
case 0:
// Expression-bodied: simple string concatenation.
sb.AppendLine(" [Projectable]");
sb.AppendLine($" public string FullName{i} => FirstName + \" \" + LastName;");
break;

case 1:
// Expression-bodied: null check combined with logical AND.
sb.AppendLine(" [Projectable]");
sb.AppendLine($" public bool IsActive{i} => DeletedAt == null && IsEnabled;");
break;

case 2:
// Expression-bodied: single-param decimal arithmetic.
sb.AppendLine(" [Projectable]");
sb.AppendLine($" public decimal TotalWithTax{i}(decimal taxRate) => Amount * (1 + taxRate);");
break;

case 3:
// Expression-bodied: multi-param string method.
sb.AppendLine(" [Projectable]");
sb.AppendLine($" public string FormatSummary{i}(string prefix, int count) => prefix + \": \" + FirstName + \" x\" + count;");
break;

case 4:
// Null-conditional member access — exercises NullConditionalRewrite transformer.
sb.AppendLine(" [Projectable(NullConditionalRewriteSupport = NullConditionalRewriteSupport.Rewrite)]");
sb.AppendLine($" public int? EmailLength{i} => Email?.Length;");
break;

case 5:
// Switch expression with relational patterns — exercises SwitchExpressionRewrite transformer.
sb.AppendLine(" [Projectable]");
sb.AppendLine($" public string GetGrade{i}(int score) => score switch {{ >= 90 => \"A\", >= 70 => \"B\", _ => \"C\" }};");
break;

case 6:
// Is-pattern (not-null) — exercises ExpressionSyntaxRewriter.VisitIsPatternExpression.
sb.AppendLine(" [Projectable]");
sb.AppendLine($" public bool HasEmail{i} => Email is not null;");
break;

case 7:
// Block-bodied if/else chain — exercises BlockStatementConverter.
sb.AppendLine(" [Projectable(AllowBlockBody = true)]");
sb.AppendLine($" public string GetStatusLabel{i}()");
sb.AppendLine(" {");
sb.AppendLine(" if (DeletedAt != null)");
sb.AppendLine(" {");
sb.AppendLine(" return \"Deleted\";");
sb.AppendLine(" }");
sb.AppendLine(" if (IsEnabled)");
sb.AppendLine(" {");
sb.AppendLine(" return \"Active: \" + FirstName;");
sb.AppendLine(" }");
sb.AppendLine(" return \"Inactive\";");
sb.AppendLine(" }");
break;

case 8:
// Block-bodied switch statement with a local variable — exercises
// BlockStatementConverter together with local-variable replacement.
sb.AppendLine(" [Projectable(AllowBlockBody = true)]");
sb.AppendLine($" public string GetPriorityName{i}()");
sb.AppendLine(" {");
sb.AppendLine(" var p = Priority;");
sb.AppendLine(" switch (p)");
sb.AppendLine(" {");
sb.AppendLine(" case 1: return \"Low\";");
sb.AppendLine(" case 2: return \"Medium\";");
sb.AppendLine(" case 3: return \"High\";");
sb.AppendLine(" default: return \"Unknown\";");
sb.AppendLine(" }");
sb.AppendLine(" }");
break;
}

sb.AppendLine();
}

sb.AppendLine("}");
sb.AppendLine();

// DTO classes with [Projectable] constructors — exercises the constructor
// projection path (ProjectableInterpreter constructor handling).
// Count scales proportionally: roughly one DTO per nine Order members.
int ctorCount = Math.Max(1, projectableCount / 9);
for (int j = 0; j < ctorCount; j++)
{
sb.AppendLine($"public class OrderSummaryDto{j}");
sb.AppendLine("{");
sb.AppendLine(" public string FullName { get; set; } = string.Empty;");
sb.AppendLine(" public decimal Total { get; set; }");
sb.AppendLine(" public bool IsActive { get; set; }");
sb.AppendLine();
// Parameterless constructor required by [Projectable] constructor support.
sb.AppendLine($" public OrderSummaryDto{j}() {{ }}");
sb.AppendLine();
sb.AppendLine(" [Projectable]");
sb.AppendLine($" public OrderSummaryDto{j}(string firstName, string lastName, decimal amount, decimal taxRate, bool isActive)");
sb.AppendLine(" {");
sb.AppendLine(" FullName = firstName + \" \" + lastName;");
sb.AppendLine(" Total = amount * (1 + taxRate);");
sb.AppendLine(" IsActive = isActive && amount > 0;");
sb.AppendLine(" }");
sb.AppendLine("}");
sb.AppendLine();
}

return sb.ToString();
}
}