CSharpLLVM is an LLVM-based compiler for CIL (Common Intermediate Language). The main goal for this compiler is to use it in low-level system development (e.g. kernels) in the C# language, where the .NET-framework is unavailable. Note that the project is still work-in-progress and does not support all features of the C# language.
Because this compiler will be mainly used for C# kernels, this means we will not support the following most notable features:
- Garbage collection: implementing this would make the kernel slower, and it is more difficult to implement because certain objects may be coming from userspace
- No .NET-framework
An important difference to the .NET framework is that we treat "System.Char" as 8-bit instead of 16-bit. This decision was influenced by the fact that this compiler's main goal is to work together with kernels.
A list of important features we support (this list does not contain all features):
- Classes, (including virtual calls and inheritance), interfaces
- Structs (with fixed buffer support)
- Most opcodes for CIL
- The basic types
Some notable features we currently don't support:
- Boxing & unboxing (need some sort of garbage collector, or we could work around this, need to investigate)
- Generic types
- Linq (depends on classes in the .NET framework)
Short term planning:
- Add support for delegates
- Add support for "Plug", this means that you will be able to provide your own implementation of certain .NET classes and/or methods.
- ...
This list can change alot. It mostly depends on what is needed, which we will find out while building the kernel.
The compiler generates code that should be linked against some runtime methods that you'll need to implement. There is a standard implementation available for these methods in runtime.c, but you can write custom implementations if you wish. More information about this (and a default implementation) can be found in the runtime folder.
We are using a NuGET package called Swigged.LLVM, the package is a wrapper for LLVM so we can use LLVM in C#. (https://www.nuget.org/packages/swigged.llvm/) For command line parsing we are also using a NuGET package called CommandLineParser. (https://www.nuget.org/packages/CommandLineParser/)