IL Runtime

1. background
   1. iOS The reason why it can't be hotter
      • Apple AppStore In the audit criteria of , It is expressly forbidden for applications to allocate memory with executable permissions
      • with JIT The script virtual machine of function cannot run
      • Unable to load dynamic link library
      • Android Google Play mandatory 64 Bits must also be used IL2CPP 了
   2. Lua and il runtime Can explain and execute
   3. from 2015 R & D started in , Now the latest version is 2.0
      • There are many online mmo, The card , leisure , Chess and card games use il runtime

2、 principle

C# Operating principle ：c# The code is compiled into cil（ Interlingua ）, And then by cil Translate it into clr（ common language ）, Finally, it is compiled into the corresponding machine code

MSIL and MonoCecil Are two key class libraries

Realization principle ：

Read dll Meta information of types and methods in , And in the method body il Assembly instruction , and dll Corresponding pdb Debug symbol file

After reading out the information to be modified , Make changes , And then write back to dll

======================================

3、 Concept note ：

1. about il runtime Come on ,dll It is an ordinary binary resource file , So it can be used assetbundle Compression or encryption ,（ At the same time, it can also be used for the main project unity To reinforce ）
2. Il runtime The object created in is unmanaged memory , You need to manage your own memory , Memory operations can be performed through pointers
3. Il runtime The interpreter of is a huge switch case Method , take c# Compiled intermediate assembly language for execution
   • Il runtime There are two patterns , One is trestle vm, The other is register type vm
   • The more assembly instructions , The lower the performance of the interpreter
   • Plank type vm： The advantage is cross platform , The disadvantage is that there are many instructions
   • register vm： The advantage is that there are fewer instructions （ Because it is associated with hardware ）, The disadvantage is that it corresponds to a specific platform architecture （ Such as x86）
4. I won't support it unsafe ,volatile,p/Invoke And other functions that need to deal with hardware or operating system

4、 Engineering structure

By the main project that does not need heat change and the heat change project of the heat change part , Two projects .

Before each bag , You need to export the heat change project as dll, Put it in the main project streamAsset Under the table of contents

5、il runtime Implementation details

1. iType： all il runtime Base class of inner type
2. iMethod： Base class of all methods
3. ILTypeInstance： All instances are of this type

6、il runtime Use

1. CLR Redirect
2. Use of delegation
3. Ctrip and asynchronous use
4. Use of reflection interface
5. Serialization Library

Be careful ： Cross domain inheritance cannot inherit more , Otherwise, the corresponding adapter will not be found

7、 How the performance

1. Il runtime vs lua （ The data （ Such as calculation , Native interface calls ） Are better than lua）
2. The configuration table should be read on demand , Otherwise, it will occupy a lot of memory
3. Il runtime 2.0 Register mode is added in , It can improve performance in Intensive Computing
4. because il runtime There is a lazy loading mechanism , Therefore, we need to use the preheating mechanism to solve the problem of slow speed for the first time
   1. The heat change project calls the main project , The performance is higher than that of the main project , Therefore, the project structure should be reasonably planned （ Some framework underlying things can be placed in the main project , Some business logic or content that changes frequently is put in hot Engineering ）
5. Update The logic of should also be put in the main project , Call the thermal engineering through events
6. Expensive independent algorithms , Such as physical calculation or routing algorithm , And other tool methods should be in the main project
7. Foreach in Use value type , stay il runtime There will be frequent packing and unpacking operations , It can lead to gc The birth of
8. Registering value type bindings will reduce gc Recycled calls
9. Use... Correctly clr Binding will speed up execution
10. Need to be in release Test in mode （editor There will be many auxiliary tools , It will affect the test results , perhaps debug There will also be a lot of debugging information processing in mode ）

8、 Division of heat range

Main works ：

         Resource management , Scene management , Network message management ,ui frame , Battle frame , Common underlying components

         agreement , Serialization and parsing

        Sdk Integrate

         Third party plug-ins

Hotter Engineering ：

         The business logic of the battle

        Ui Business logic

         agreement , Configuration table

        Sdk Call logic

Be careful ：

Cross module calls should use event dispatch to reduce coupling , Convenient for follow-up heat

Use link.xml Reserve main engineering interface

Used in events that need to be handled by the main project object Universal parameters of

Use xil Of aop The thermal repair scheme provides the minimum guarantee of the main engineering code

Don't use it more frequently in hot projects monobehaver, Because it will be designed to prefabricate and serialize the fields on the corresponding script , This part is in unity The engine layer is complex and the serialization interface is not open