LLVM JIT: An Example

This code builds a minimal JIT engine to execute LLVM-IR. It does not cover generation of LLVM-IR.

Build

• Adding repository for LLVM-10
  • For Ubuntu 18.04 (Ubuntu 20.04 already has LLVM-10 in the repository)

    sudo apt-add-repository "deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-10 main"

  • Others: Visit the LLVM apt website above and follow instructions.
• sudo apt-get install libllvm10 llvm-10-dev clang-10
• make

This should produce an executable named lljit.exe.

Run

• This will JIT compile the LLVM-IR in examples/helloworld.ll and execute the function jitentry in it. It should print "Hello world" on your terminal.

  ./lljit.exe examples/helloworld.ll

• The helloworld example LLVM-IR was generated from its C file using the command

  clang-10 -emit-llvm -S helloworld.c

Testsuite

Building the project should also build testsuite.exe, which can simply be run as ./testsuite.exe, and it will JIT compile and run the helloworld.ll example described above.