From 5e1935c310d305cac242ba1d1511073d4135a030 Mon Sep 17 00:00:00 2001
From: PJB3005 <pieterjan.briers+git@gmail.com>
Date: Mon, 13 Jan 2025 05:52:31 +0100
Subject: [PATCH] Optimize ByRefEventAnalyzer

According to a log, like 20 seconds of the build is spent in this analyzer. It now takes ~200ms. Hooray!
---
 Robust.Analyzers/ByRefEventAnalyzer.cs | 48 ++++++++++++++++----------
 1 file changed, 30 insertions(+), 18 deletions(-)

diff --git a/Robust.Analyzers/ByRefEventAnalyzer.cs b/Robust.Analyzers/ByRefEventAnalyzer.cs
index d5c2cad796a..9669892aff2 100644
--- a/Robust.Analyzers/ByRefEventAnalyzer.cs
+++ b/Robust.Analyzers/ByRefEventAnalyzer.cs
@@ -54,32 +54,44 @@ public override void Initialize(AnalysisContext context)
     {
         context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.Analyze | GeneratedCodeAnalysisFlags.ReportDiagnostics);
         context.EnableConcurrentExecution();
-        context.RegisterOperationAction(CheckEventRaise, OperationKind.Invocation);
+        context.RegisterCompilationStartAction(compilationContext =>
+        {
+            var raiseMethods = compilationContext.Compilation
+                .GetTypeByMetadataName("Robust.Shared.GameObjects.EntitySystem")?
+                .GetMembers()
+                .Where(m => m.Name.Contains("RaiseLocalEvent") && m.Kind == SymbolKind.Method)
+                .Cast<IMethodSymbol>();
+
+            var busRaiseMethods = compilationContext.Compilation
+                .GetTypeByMetadataName("Robust.Shared.GameObjects.EntityEventBus")?
+                .GetMembers()
+                .Where(m => m.Name.Contains("RaiseLocalEvent") && m.Kind == SymbolKind.Method)
+                .Cast<IMethodSymbol>();
+
+            if (raiseMethods == null)
+                return;
+
+            if (busRaiseMethods != null)
+                raiseMethods = raiseMethods.Concat(busRaiseMethods);
+
+            var raiseMethodsArray = raiseMethods.ToArray();
+
+            compilationContext.RegisterOperationAction(
+                ctx => CheckEventRaise(ctx, raiseMethodsArray),
+                OperationKind.Invocation);
+        });
     }
 
-    private void CheckEventRaise(OperationAnalysisContext context)
+    private static void CheckEventRaise(
+        OperationAnalysisContext context,
+        IReadOnlyCollection<IMethodSymbol> raiseMethods)
     {
         if (context.Operation is not IInvocationOperation operation)
             return;
 
-        var raiseMethods = context.Compilation
-            .GetTypeByMetadataName("Robust.Shared.GameObjects.EntitySystem")?
-            .GetMembers()
-            .Where(m => m.Name.Contains("RaiseLocalEvent") && m.Kind == SymbolKind.Method)
-            .Cast<IMethodSymbol>();
-
-        var busRaiseMethods = context.Compilation
-            .GetTypeByMetadataName("Robust.Shared.GameObjects.EntityEventBus")?
-            .GetMembers()
-            .Where(m => m.Name.Contains("RaiseLocalEvent") && m.Kind == SymbolKind.Method)
-            .Cast<IMethodSymbol>();
-
-        if (raiseMethods == null)
+        if (!operation.TargetMethod.Name.Contains("RaiseLocalEvent"))
             return;
 
-        if (busRaiseMethods != null)
-            raiseMethods = raiseMethods.Concat(busRaiseMethods);
-
         if (!raiseMethods.Any(m => m.Equals(operation.TargetMethod.OriginalDefinition, Default)))
         {
             // If you try to do this normally by concatenating like busRaiseMethods above