feat: Add RPC Name Lookup Table Provided by NetworkBehaviourILPP (#875)

* Adding RPC Name Information through ILPP and Code Gen (MTT-802)

* Updated based on comments and feedback

* Updating comment to reflect better

* Setup a list to avoid manipulating the string.
Updated the naming around to better identify the two lists

* Using compiled assembly defines list instead of macros

* Passing defines as argument instead of storing them.
Updated the comment in network manager to better reflect what is going
on.

* minor refactor

Co-authored-by: M. Fatih MAR <mfatihmar@gmail.com>

Author: Jean-Sébastien Fauteux

com.unity.multiplayer.mlapi/Editor/CodeGen/NetworkBehaviourILPP.cs

@@ -57,7 +57,7 @@ public override ILPostProcessResult Process(ICompiledAssembly compiledAssembly)
                     mainModule.GetTypes()
                         .Where(t => t.IsSubclassOf(CodeGenHelpers.NetworkBehaviour_FullName))
                         .ToList()
-                        .ForEach(ProcessNetworkBehaviour);
+                        .ForEach(b => ProcessNetworkBehaviour(b, compiledAssembly.Defines));
                 }
                 else
                 {
@@ -95,6 +95,8 @@ public override ILPostProcessResult Process(ICompiledAssembly compiledAssembly)
         private FieldReference m_NetworkManager_LogLevel_FieldRef;
         private FieldReference m_NetworkManager_ntable_FieldRef;
         private MethodReference m_NetworkManager_ntable_Add_MethodRef;
+        private FieldReference m_NetworkManager_rpc_name_table_FieldRef;
+        private MethodReference m_NetworkManager_rpc_name_table_Add_MethodRef;
         private TypeReference m_NetworkBehaviour_TypeRef;
         private MethodReference m_NetworkBehaviour_BeginSendServerRpc_MethodRef;
         private MethodReference m_NetworkBehaviour_EndSendServerRpc_MethodRef;
@@ -164,6 +166,7 @@ public override ILPostProcessResult Process(ICompiledAssembly compiledAssembly)
         private const string k_NetworkManager_LogLevel = nameof(NetworkManager.LogLevel);
 #pragma warning disable 618
         private const string k_NetworkManager_ntable = nameof(NetworkManager.__ntable);
+        private const string k_NetworkManager_rpc_name_table = nameof(NetworkManager.__rpc_name_table);
 
         private const string k_NetworkBehaviour_BeginSendServerRpc = nameof(NetworkBehaviour.__beginSendServerRpc);
         private const string k_NetworkBehaviour_EndSendServerRpc = nameof(NetworkBehaviour.__endSendServerRpc);
@@ -235,6 +238,10 @@ private bool ImportReferences(ModuleDefinition moduleDefinition)
                         m_NetworkManager_ntable_FieldRef = moduleDefinition.ImportReference(fieldInfo);
                         m_NetworkManager_ntable_Add_MethodRef = moduleDefinition.ImportReference(fieldInfo.FieldType.GetMethod("Add"));
                         break;
+                    case k_NetworkManager_rpc_name_table:
+                        m_NetworkManager_rpc_name_table_FieldRef = moduleDefinition.ImportReference(fieldInfo);
+                        m_NetworkManager_rpc_name_table_Add_MethodRef = moduleDefinition.ImportReference(fieldInfo.FieldType.GetMethod("Add"));
+                        break;
                 }
             }
 
@@ -523,9 +530,13 @@ private bool ImportReferences(ModuleDefinition moduleDefinition)
             return true;
         }
 
-        private void ProcessNetworkBehaviour(TypeDefinition typeDefinition)
+        private void ProcessNetworkBehaviour(TypeDefinition typeDefinition, string[] assemblyDefines)
         {
-            var staticHandlers = new List<(uint Hash, MethodDefinition Method)>();
+            var rpcHandlers = new List<(uint RpcHash, MethodDefinition RpcHandler)>();
+            var rpcNames = new List<(uint RpcHash, string RpcName)>();
+
+            bool isEditorOrDevelopment = assemblyDefines.Contains("UNITY_EDITOR") || assemblyDefines.Contains("DEVELOPMENT_BUILD");
+
             foreach (var methodDefinition in typeDefinition.Methods)
             {
                 var rpcAttribute = CheckAndGetRPCAttribute(methodDefinition);
@@ -541,10 +552,16 @@ private void ProcessNetworkBehaviour(TypeDefinition typeDefinition)
                 }
 
                 InjectWriteAndCallBlocks(methodDefinition, rpcAttribute, methodDefHash);
-                staticHandlers.Add((methodDefHash, GenerateStaticHandler(methodDefinition, rpcAttribute)));
+
+                rpcHandlers.Add((methodDefHash, GenerateStaticHandler(methodDefinition, rpcAttribute)));
+
+                if (isEditorOrDevelopment)
+                {
+                    rpcNames.Add((methodDefHash, methodDefinition.Name));
+                }
             }
 
-            if (staticHandlers.Count > 0)
+            if (rpcHandlers.Count > 0 || rpcNames.Count > 0)
             {
                 var staticCtorMethodDef = typeDefinition.GetStaticConstructor();
                 if (staticCtorMethodDef == null)
@@ -562,24 +579,29 @@ private void ProcessNetworkBehaviour(TypeDefinition typeDefinition)
 
                 var instructions = new List<Instruction>();
                 var processor = staticCtorMethodDef.Body.GetILProcessor();
-                foreach (var (hash, method) in staticHandlers)
-                {
-                    if (hash == 0 || method == null)
-                    {
-                        continue;
-                    }
 
-                    typeDefinition.Methods.Add(method);
+                foreach (var (rpcHash, rpcHandler) in rpcHandlers)
+                {
+                    typeDefinition.Methods.Add(rpcHandler);
 
-                    // NetworkManager.__ntable.Add(HandlerHash, HandlerMethod);
+                    // NetworkManager.__ntable.Add(RpcHash, HandleFunc);
                     instructions.Add(processor.Create(OpCodes.Ldsfld, m_NetworkManager_ntable_FieldRef));
-                    instructions.Add(processor.Create(OpCodes.Ldc_I4, unchecked((int)hash)));
+                    instructions.Add(processor.Create(OpCodes.Ldc_I4, unchecked((int)rpcHash)));
                     instructions.Add(processor.Create(OpCodes.Ldnull));
-                    instructions.Add(processor.Create(OpCodes.Ldftn, method));
+                    instructions.Add(processor.Create(OpCodes.Ldftn, rpcHandler));
                     instructions.Add(processor.Create(OpCodes.Newobj, m_NetworkHandlerDelegateCtor_MethodRef));
                     instructions.Add(processor.Create(OpCodes.Call, m_NetworkManager_ntable_Add_MethodRef));
                 }
 
+                foreach (var (rpcHash, rpcName) in rpcNames)
+                {
+                    // NetworkManager.__rpc_name_table.Add(RpcHash, RpcName);
+                    instructions.Add(processor.Create(OpCodes.Ldsfld, m_NetworkManager_rpc_name_table_FieldRef));
+                    instructions.Add(processor.Create(OpCodes.Ldc_I4, unchecked((int)rpcHash)));
+                    instructions.Add(processor.Create(OpCodes.Ldstr, rpcName));
+                    instructions.Add(processor.Create(OpCodes.Call, m_NetworkManager_rpc_name_table_Add_MethodRef));
+                }
+
                 instructions.Reverse();
                 instructions.ForEach(instruction => processor.Body.Instructions.Insert(0, instruction));
             }

com.unity.multiplayer.mlapi/Editor/CodeGen/RuntimeAccessModifiersILPP.cs

@@ -1,6 +1,7 @@
 #if UNITY_2020_2_OR_NEWER
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using Mono.Cecil;
 using Mono.Cecil.Cil;
 using Unity.CompilationPipeline.Common.Diagnostics;
@@ -49,7 +50,7 @@ public override ILPostProcessResult Process(ICompiledAssembly compiledAssembly)
                     switch (typeDefinition.Name)
                     {
                         case nameof(NetworkManager):
-                            ProcessNetworkManager(typeDefinition);
+                            ProcessNetworkManager(typeDefinition, compiledAssembly.Defines);
                             break;
                         case nameof(NetworkBehaviour):
                             ProcessNetworkBehaviour(typeDefinition);
@@ -81,14 +82,22 @@ public override ILPostProcessResult Process(ICompiledAssembly compiledAssembly)
             return new ILPostProcessResult(new InMemoryAssembly(pe.ToArray(), pdb.ToArray()), m_Diagnostics);
         }
 
-        private void ProcessNetworkManager(TypeDefinition typeDefinition)
+        private void ProcessNetworkManager(TypeDefinition typeDefinition, string[] assemblyDefines)
         {
             foreach (var fieldDefinition in typeDefinition.Fields)
             {
                 if (fieldDefinition.Name == nameof(NetworkManager.__ntable))
                 {
                     fieldDefinition.IsPublic = true;
                 }
+
+                if (assemblyDefines.Contains("UNITY_EDITOR") || assemblyDefines.Contains("DEVELOPMENT_BUILD"))
+                {
+                    if (fieldDefinition.Name == nameof(NetworkManager.__rpc_name_table))
+                    {
+                        fieldDefinition.IsPublic = true;
+                    }
+                }
             }
         }
 

com.unity.multiplayer.mlapi/Runtime/Core/NetworkManager.cs

@@ -35,10 +35,21 @@ public class NetworkManager : MonoBehaviour, INetworkUpdateSystem, IProfilableTr
 #if UNITY_2020_2_OR_NEWER
         // RuntimeAccessModifiersILPP will make this `public`
         internal static readonly Dictionary<uint, Action<NetworkBehaviour, NetworkSerializer, __RpcParams>> __ntable = new Dictionary<uint, Action<NetworkBehaviour, NetworkSerializer, __RpcParams>>();
-#else
+
+#if UNITY_EDITOR || DEVELOPMENT_BUILD
+        // RuntimeAccessModifiersILPP will make this `public`
+        internal static readonly Dictionary<uint, string> __rpc_name_table = new Dictionary<uint, string>();
+#else // !(UNITY_EDITOR || DEVELOPMENT_BUILD)
+        // RuntimeAccessModifiersILPP and NetworkBehaviourILPP requires a variable with this name to exist when outside of Debug build or Editor.
+        // If the name doesn't exist, generation and compilation errors occurs.
+        // For the sake of consistency, we are using the same type.
+        // Final note: this variable will not be used. Since it's never initialized, it will not be in the memory footprint.
+        internal static readonly Dictionary<uint, string> __rpc_name_table = null;
+#endif // UNITY_EDITOR || DEVELOPMENT_BUILD
+#else // !UNITY_2020_2_OR_NEWER
         [Obsolete("Please do not use, will no longer be exposed in the future versions (framework internal)")]
         public static readonly Dictionary<uint, Action<NetworkBehaviour, NetworkSerializer, __RpcParams>> __ntable = new Dictionary<uint, Action<NetworkBehaviour, NetworkSerializer, __RpcParams>>();
-#endif
+#endif // UNITY_2020_2_OR_NEWER
 #pragma warning restore IDE1006 // restore naming rule violation check
 
 #if DEVELOPMENT_BUILD || UNITY_EDITOR