From e2713fc5575b170cb881b38079a6773c9fe30912 Mon Sep 17 00:00:00 2001
From: Daniel Romano <108014683+daniel-romano-DD@users.noreply.github.com>
Date: Fri, 12 Jan 2024 11:13:51 +0100
Subject: [PATCH] Removed Activator calls for performance reasons

---
 .../AspectsDefinitionsGenerator.cs            |  2 +-
 .../AspectsDefinitions/Helpers.cs             | 42 ++++++++++++++++++-
 2 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/tracer/src/Datadog.Trace.SourceGenerators/AspectsDefinitions/AspectsDefinitionsGenerator.cs b/tracer/src/Datadog.Trace.SourceGenerators/AspectsDefinitions/AspectsDefinitionsGenerator.cs
index 2ca8ffbdfea1..c565e0926446 100644
--- a/tracer/src/Datadog.Trace.SourceGenerators/AspectsDefinitions/AspectsDefinitionsGenerator.cs
+++ b/tracer/src/Datadog.Trace.SourceGenerators/AspectsDefinitions/AspectsDefinitionsGenerator.cs
@@ -158,7 +158,7 @@ private static IReadOnlyList<string> GetAspectSources(Compilation compilation, I
             var arguments = attribute.ConstructorArguments.Select(a => GetArgument(a)).ToArray();
             var type = Resolve(attribute);
             if (type == null) { return null; }
-            var res = Activator.CreateInstance(type, arguments);
+            var res = Helpers.CreateAttributeInstance(type, arguments); // Activator.CreateInstance(type, arguments);
             return res;
         }
         catch (Exception err)
diff --git a/tracer/src/Datadog.Trace.SourceGenerators/AspectsDefinitions/Helpers.cs b/tracer/src/Datadog.Trace.SourceGenerators/AspectsDefinitions/Helpers.cs
index 35e3afb73842..0fa21a2e84f8 100644
--- a/tracer/src/Datadog.Trace.SourceGenerators/AspectsDefinitions/Helpers.cs
+++ b/tracer/src/Datadog.Trace.SourceGenerators/AspectsDefinitions/Helpers.cs
@@ -7,7 +7,8 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Text;
+using Datadog.Trace.Iast;
+using Datadog.Trace.Iast.Dataflow;
 
 namespace Datadog.Trace.SourceGenerators.AspectsDefinitions
 {
@@ -23,5 +24,44 @@ internal static class Helpers
             Array.Copy(array, destinationArray, array.Length);
             return destinationArray;
         }
+
+        internal static object? CreateAttributeInstance(Type attributeType, object?[] arguments)
+        {
+            int x = 0;
+            if (attributeType == typeof(AspectClassAttribute))
+            {
+                if (arguments == null || arguments.Length == 0) { return new AspectClassAttribute(); }
+                else if (arguments.Length == 1) { return new AspectClassAttribute((string)arguments[x++]!); }
+                else if (arguments.Length == 3) { return new AspectClassAttribute((string)arguments[x++]!, (AspectType)arguments[x++]!, (VulnerabilityType[])arguments[x++]!); }
+                else if (arguments.Length == 4 && arguments[1]?.GetType() == typeof(AspectFilter)) { return new AspectClassAttribute((string)arguments[x++]!, (AspectFilter)arguments[x++]!, (AspectType)arguments[x++]!, (VulnerabilityType[])arguments[x++]!); }
+                else if (arguments.Length == 4) { return new AspectClassAttribute((string)arguments[x++]!, (AspectFilter[])arguments[x++]!, (AspectType)arguments[x++]!, (VulnerabilityType[])arguments[x++]!); }
+            }
+            else if (attributeType == typeof(AspectMethodReplaceAttribute))
+            {
+                if (arguments.Length == 1) { return new AspectMethodReplaceAttribute((string)arguments[x++]!); }
+                else if (arguments.Length == 2) { return new AspectMethodReplaceAttribute((string)arguments[x++]!, (AspectFilter[])arguments[x++]!); }
+                else if (arguments.Length == 3 && arguments[1]?.GetType() == typeof(string)) { return new AspectMethodReplaceAttribute((string)arguments[x++]!, (string)arguments[x++]!, (AspectFilter[])arguments[x++]!); }
+                else if (arguments.Length == 3) { return new AspectMethodReplaceAttribute((string)arguments[x++]!, (AspectType)arguments[x++]!, (VulnerabilityType[])arguments[x++]!); }
+            }
+            else if (attributeType == typeof(AspectCtorReplaceAttribute))
+            {
+                if (arguments.Length == 1) { return new AspectCtorReplaceAttribute((string)arguments[x++]!); }
+                else if (arguments.Length == 2) { return new AspectCtorReplaceAttribute((string)arguments[x++]!, (AspectFilter[])arguments[x++]!); }
+                else if (arguments.Length == 3) { return new AspectCtorReplaceAttribute((string)arguments[x++]!, (AspectType)arguments[x++]!, (VulnerabilityType[])arguments[x++]!); }
+            }
+            else if (attributeType == typeof(AspectMethodInsertAfterAttribute))
+            {
+                if (arguments.Length == 1) { return new AspectMethodInsertAfterAttribute((string)arguments[x++]!); }
+                else if (arguments.Length == 3) { return new AspectMethodInsertAfterAttribute((string)arguments[x++]!, (AspectType)arguments[x++]!, (VulnerabilityType[])arguments[x++]!); }
+            }
+            else if (attributeType == typeof(AspectMethodInsertBeforeAttribute))
+            {
+                if (arguments.Length == 2) { return new AspectMethodInsertBeforeAttribute((string)arguments[x++]!, (int[])arguments[x++]!); }
+                else if (arguments.Length == 3 && arguments[1]?.GetType() == typeof(int)) { return new AspectMethodInsertBeforeAttribute((string)arguments[x++]!, (int)arguments[x++]!, (bool)arguments[x++]!); }
+                else if (arguments.Length == 3) { return new AspectMethodInsertBeforeAttribute((string)arguments[x++]!, (int[])arguments[x++]!, (bool[])arguments[x++]!); }
+            }
+
+            throw new ArgumentException($"No constructor helper for {attributeType} and {arguments.Length} arguments", "attributeType");
+        }
     }
 }