How to embed LLVM?

Question

The LLVM Core project consists of:

• Compiler - converts source code to LLVM IR
• VM - executes compiled IR code

How can I embed the VM to a C++ application?

Emmott

More typically LLVM is used to compile directly to machine code. I'm not familiar with the latest, but Apple Clang is the most active LLVM project, and it's being postured as a competitor to GCC. – Benford

@Potatoswatter: unfortunately Clang is still a bit lacking (especially in C++0x features) but I have great hope indeed. Also the modular design is just so useful, a great many editors could benefit from its parser. – Pass

Answer 1

Take a look at the HowToUseJIT example in LLVM.

Dichroscope

Answer 2

The LLVM is really a collection of libraries that you can link to, so it's pretty easy to embed. More often the LLVM takes IR that you generate and compiles it directly to machine code. There is also a library available to interpret and execute IR for platforms that do not support JIT compilation.

There's a pretty good tutorial available on the LLVM website here: http://llvm.org/docs/tutorial/. I suggest that you go through that and then ask more specific questions if you have them.

Forbidding

Likely you'll need several of them. LLVMCore, LLVMSupport, and LLVMSystem are the bare minimum. It really depends on what you want to do, exactly. For a somewhat outdated list, see: llvm.org/docs/UsingLibraries.html – Forbidding