IL2CPP

IL2CPP stands for Intermediate Language to C++. It is a technology developed by Unity Technologies used to convert code written in C# and other .NET languages into C++ code. This C++ code is then compiled into native machine code for various target platforms. The primary purpose of IL2CPP is to improve performance and enable deployment on platforms that do not natively support the .NET Common Language Runtime (CLR).

When a Unity project is built, the C# scripts are first compiled into Common Intermediate Language (CIL) or MSIL. IL2CPP then takes this CIL bytecode and translates it into equivalent C++ code. This translation process involves mapping CIL instructions to C++ functions and data structures. The generated C++ code is then compiled using a platform-specific C++ compiler, such as Clang for iOS and Android, or MSVC for Windows.

This native compilation offers several advantages. It generally leads to better runtime performance compared to running CIL through a Just-In-Time (JIT) compiler, especially on mobile and console platforms where JIT compilation might be restricted or less efficient. IL2CPP also facilitates deployment to platforms that do not have a managed runtime environment. By converting to C++, Unity games can run on a wider range of hardware. Additionally, IL2CPP can enhance security by making it more difficult to reverse-engineer the game's logic compared to easily decompiled CIL. The technology is a key component of Unity's build pipeline for achieving high performance and broad platform support.