Block explicit layout types in sandboxing.

Robust.Shared/ContentPack/AssemblyTypeChecker.cs

@@ -193,6 +193,10 @@ namespace Robust.Shared.ContentPack
 
             _sawmill.Debug($"Unmanaged methods... {fullStopwatch.ElapsedMilliseconds}ms");
 
+            CheckNoTypeAbuse(reader, errors);
+
+            _sawmill.Debug($"Type abuse... {fullStopwatch.ElapsedMilliseconds}ms");
+
             CheckMemberReferences(loadedConfig, members, errors);
 
             foreach (var error in errors)
@@ -311,6 +315,27 @@ namespace Robust.Shared.ContentPack
             }
         }
 
+        private static void CheckNoTypeAbuse(MetadataReader reader, ConcurrentBag<SandboxError> errors)
+        {
+            foreach (var typeDefHandle in reader.TypeDefinitions)
+            {
+                var typeDef = reader.GetTypeDefinition(typeDefHandle);
+                if ((typeDef.Attributes & TypeAttributes.ExplicitLayout) != 0)
+                {
+                    // The C# compiler emits explicit layout types for some array init logic. These have no fields.
+                    // Only ban explicit layout if it has fields.
+
+                    var type = GetTypeFromDefinition(reader, typeDefHandle);
+
+                    if (typeDef.GetFields().Count > 0)
+                    {
+                        var err = $"Explicit layout type {type} may not have fields.";
+                        errors.Add(new SandboxError(err));
+                    }
+                }
+            }
+        }
+
         private void CheckMemberReferences(
             SandboxConfig sandboxConfig,
             List<MMemberRef> members,

Robust.Shared/Timing/ProfilingManager.cs

@@ -0,0 +1,33 @@
+using System.Collections.Generic;
+using Robust.Shared.Utility.Collections;
+
+namespace Robust.Shared.Timing;
+
+// No interfaces here,
+public sealed class ProfilingManager
+{
+    public bool IsEnabled;
+
+    // I don't care that this isn't a tree I will call upon the string tree just like in BYOND.
+    private readonly Dictionary<string, int> _stringTreeIndices = new();
+    private ValueList<string> _stringTree;
+
+    public struct Cmd
+    {
+        public CmdType Type;
+
+        public int StringId;
+        public float Value;
+    }
+
+    public struct CmdSample
+    {
+        // public
+    }
+
+    public enum CmdType
+    {
+        Invalid,
+        Sample
+    }
+}