RLLVM is an R interface to LLVM. This interface allows one to create compiled code from within R through LLVM's intermediate representation (IR), which LLVM can then extensively and efficiently optimize.
For examples, see the RLLVM page on Omegahat.
The current repository builds against LLVM 3.5, 3.6, 3.7, and3.8. Importantly, recent versions of LLVM default to the MCJIT execution engine. This unfortunately has very limited ability to invoke routines compiled via Rllvm, i.e., using the .llvm() and run() functions. Acccordingly, we have implemented a simple (but reasonably comprehensive) mechanism to invoke these routines. We use the Rffi package to do this. We might shift to the rdyncall package.
So this package now requires the Rffi package. This comes with its own version of libffi, but will find a more up-to-date version if it is installed (see pkg-config).
These packages are not yet on CRAN.