DLL: Add initial code to create custom attributes

Il2CppInspector.Common/Il2CppInspector.csproj

@@ -38,6 +38,7 @@
   </ItemGroup>
 
   <ItemGroup>
+    <PackageReference Include="dnlib" Version="3.3.2" />
     <PackageReference Include="McMaster.NETCore.Plugins" Version="1.3.1" />
     <PackageReference Include="Microsoft.NETCore.Targets" Version="3.0.0" PrivateAssets="all" />
     <PackageReference Include="CxxDemangler" Version="0.2.4.11">

Il2CppInspector.Common/Outputs/AssemblyShims.cs

@@ -0,0 +1,109 @@
+/*
+    Copyright 2017-2020 Perfare - https://github.com/Perfare/Il2CppDumper
+    Copyright 2021 Katy Coe - http://www.djkaty.com - https://github.com/djkaty
+
+    All rights reserved.
+*/
+
+using System;
+using System.IO;
+using dnlib.DotNet;
+using dnlib.DotNet.Emit;
+using Il2CppInspector.Reflection;
+using Assembly = System.Reflection.Assembly;
+using BindingFlags = System.Reflection.BindingFlags;
+
+namespace Il2CppInspector.Outputs
+{
+    public static class dnlibExtensions
+    {
+        // Add a default parameterless constructor that calls a specified base constructor
+        public static MethodDefUser AddDefaultConstructor(this TypeDefUser type, IMethod @base) {
+            var ctor = new MethodDefUser(".ctor", MethodSig.CreateInstance(type.Module.CorLibTypes.Void),
+                MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.SpecialName | MethodAttributes.RTSpecialName);
+
+            var ctorBody = new CilBody();
+            ctorBody.Instructions.Add(OpCodes.Ldarg_0.ToInstruction());
+            ctorBody.Instructions.Add(OpCodes.Call.ToInstruction(@base));
+            ctorBody.Instructions.Add(OpCodes.Ret.ToInstruction());
+
+            type.Methods.Add(ctor);
+            return ctor;
+        }
+    }
+
+    // Output module to create .NET DLLs containing type definitions
+    public class AssemblyShims
+    {
+        private readonly TypeModel model;
+
+        // The namespace for our custom types
+        private const string rootNamespace = "Il2CppInspector.DLL"; // Il2CppDummyDll
+
+        public AssemblyShims(TypeModel model) => this.model = model;
+
+        // Create a new DLL assembly definition
+        private ModuleDefUser CreateAssembly(string name) {
+            var module = new ModuleDefUser(name + ".dll") { Kind = ModuleKind.Dll };
+
+            var ourVersion = Assembly.GetAssembly(typeof(Il2CppInspector)).GetName().Version;
+
+            var asm = new AssemblyDefUser(name, ourVersion);
+            asm.Modules.Add(module);
+
+            return module;
+        }
+
+        // Generate and save all DLLs
+        public void Write(string outputPath) {
+            Directory.CreateDirectory(outputPath);
+
+            // Create DLL with our custom types
+            var module = CreateAssembly("Il2CppInspector");
+
+            var importer = new Importer(module);
+            var attributeCtor = typeof(Attribute).GetConstructors(BindingFlags.NonPublic | BindingFlags.Instance)[0];
+            var attributeTypeRef = importer.Import(typeof(Attribute));
+            var attributeCtorRef = importer.Import(attributeCtor);
+
+            var stringField = new FieldSig(module.CorLibTypes.String);
+
+            // Create a type deriving from System.Attribute and add it to the assembly
+            TypeDefUser createAttribute(string name) {
+                var attribute = new TypeDefUser(rootNamespace, name, attributeTypeRef);
+                attribute.Attributes = TypeAttributes.Public | TypeAttributes.BeforeFieldInit;
+                module.Types.Add(attribute);
+                return attribute;
+            }
+
+            // Create our custom attributes for compatibility with Il2CppDumper
+            var addressAttribute = createAttribute("AddressAttribute");
+            addressAttribute.Fields.Add(new FieldDefUser("RVA", stringField, FieldAttributes.Public));
+            addressAttribute.Fields.Add(new FieldDefUser("Offset", stringField, FieldAttributes.Public));
+            addressAttribute.Fields.Add(new FieldDefUser("VA", stringField, FieldAttributes.Public));
+            addressAttribute.Fields.Add(new FieldDefUser("Slot", stringField, FieldAttributes.Public));
+            addressAttribute.AddDefaultConstructor(attributeCtorRef);
+
+            var fieldOffsetAttribute = createAttribute("FieldOffsetAttribute");
+            fieldOffsetAttribute.Fields.Add(new FieldDefUser("Offset", stringField, FieldAttributes.Public));
+            fieldOffsetAttribute.AddDefaultConstructor(attributeCtorRef);
+
+            var attributeAttribute = createAttribute("AttributeAttribute");
+            attributeAttribute.Fields.Add(new FieldDefUser("Name", stringField, FieldAttributes.Public));
+            attributeAttribute.Fields.Add(new FieldDefUser("RVA", stringField, FieldAttributes.Public));
+            attributeAttribute.Fields.Add(new FieldDefUser("Offset", stringField, FieldAttributes.Public));
+            attributeAttribute.AddDefaultConstructor(attributeCtorRef);
+
+            var metadataOffsetAttribute = createAttribute("MetadataOffsetAttribute");
+            metadataOffsetAttribute.Fields.Add(new FieldDefUser("Offset", stringField, FieldAttributes.Public));
+            metadataOffsetAttribute.AddDefaultConstructor(attributeCtorRef);
+
+            var tokenAttribute = createAttribute("TokenAttribute");
+            tokenAttribute.Fields.Add(new FieldDefUser("Token", stringField, FieldAttributes.Public));
+            tokenAttribute.AddDefaultConstructor(attributeCtorRef);
+
+            // Write DLL to disk
+            module.Write(Path.Combine(outputPath, module.Name));
+        }
+    }
+}

README.md

@@ -707,6 +707,7 @@ This project uses:
 - [Ookii.Dialogs.Wpf](https://github.com/augustoproiete/ookii-dialogs-wpf)
 - [XamlAnimatedGif](https://github.com/XamlAnimatedGif/WpfAnimatedGif) by Thomas Levesque
 - [.NET Core Plugins](https://github.com/natemcmaster/DotNetCorePlugins) by Nate McMaster
+- [dnlib](https://github.com/0xd4d/dnlib) by 0xd4d
 
 Thanks to the following individuals whose code and research helped me develop this tool: