ILVirtualMachine

Brief

a simple implementation of virtual machine which can run il parsed by mono cecil.

Hello World

open SampleScene and run it.

click Hello button, you will see a log Hello World in the console:

which is run by vm, not directly call.

How to use

see HelloBtn.cs:

load assembly by Mono.Cecil first (we default load assembly currently in use, you can replace it also):

// default parse from: "Library/ScriptAssemblies/Assembly-CSharp.dll"
using (var assemblyHandle = new AssemblyHandle())
{
    // ...
}

get MethodDefinition of method which you want to invoke:

// get MethodDefinition of HelloBtn.SayHello
var assemblyDef = assemblyHandle.GetAssembly();
var classTypeDef = assemblyDef.MainModule.GetType("HelloBtn");
var methodTypeDef = classTypeDef.Methods.First(m => m.Name == "SayHello");

invoke it by vm:

var vm = new ILVirtualMachine();
var parameters = new object[] { this };
vm.Execute(methodTypeDef, parameters);

C# Hotfix

you can treat this as a enhanced version of Unity-CSharpHotfix.
it can also replace c# method logic at runtime without stop unity play (and with less bugs).

to do this, you need do:

• compile: generate .dll with new method code, then rollback, we will hotfix old .dll by new one
• inject: add marks on method you want to modify later
• hotfix: run hotfix, then the method logic is replaced by new logic

Compile

for example, modify HelloBtn.cs as:

// use ILVM.Hotfix to mark the method need be replaced
[ILVM.Hotfix]
public void OnClick()
{
    // these are new logic
    Debug.Log("Hello World after hotfix");

    
    // these are old logic
    // // default parse from: "Library/ScriptAssemblies/Assembly-CSharp.dll"
    // using (var assemblyHandle = new AssemblyHandle())
    // {
    //     // get MethodDefinition of HelloBtn.SayHello
    //     var assemblyDef = assemblyHandle.GetAssembly();
    //     var classTypeDef = assemblyDef.MainModule.GetType("HelloBtn");
    //     var methodTypeDef = classTypeDef.Methods.First(m => m.Name == "SayHello");

    //     // invoke method by Virual Machine
    //     var vm = new ILVirtualMachine();
    //     var parameters = new object[] { this };
    //     vm.Execute(methodTypeDef, parameters);
    // }
}  

compile code, we will get a new Assembly-CSharp.dll.
move it to {project}/Library/ILVM folder,
then rollback code modifications.

Inject

you need add HelloBtn to ILVmInjectConfig.json:

{
  "injectClass": [
	"HelloBtn"
  ], 
"nameSpaceFilter": [
		"ILVM",
		"System", 
		"UnityEngine",  
		"UnityEditor" 
	], 
"classNameFilter": [
		"ConsoleProDebug"
	],
"methodNameFilter":  [
	]
}

• injectClass: the class type you may hotfix later
• **Filter: blacklist, filter the namespace & class & method you dont want to hotfix. cause if there're too many, inject will run slowly.

then click Unity Toolbar->ILVM->Inject:

Hotfix

play game, click hello btn, sill get Hello World in console:

then click Unity Toolbar->ILVM->Hotfix:

we can get:

also you can use Clear Hotfix to rollback to old logic.