Installations for the synthesizer-llvm tutorial

The following instructions might appear to be lengthy and cumbersome, but they boil essentially down to: Install LLVM and SoX, create and install a custom llvm.pc file and then install synthesizer-llvm via the common Cabal workflow.

Installing LLVM

The tutorial relies on the LLVM compiler framework. The synthesizer-llvm package uses it like a machine-independent assembly language. Currently we support LLVM-3.8 optimally. This was the current version until 2016-09-02. In principle we support LLVM versions back to 3.4, but there were some changes in the types of so called intrinsics that are used to address processor specific machine instructions. If your LLVM version is too old, some synthesizer-llvm examples will fail with errors like this one:

Intrinsic has incorrect argument type!
<4 x float> (<4 x float>, <4 x float>, i8)* @llvm.x86.sse41.dpps
LLVM ERROR: Broken function found, compilation aborted!

If you cannot manage to install LLVM-3.8, you may ask me and we will find fixes to support older versions of LLVM. However, LLVM-3.6 had a serious problem with callback functions that I could not work around.

On Debian and Ubuntu you can install appropriate LLVM-3.8 packages from the LLVM package repositories.

On Windows 64 bit you may download my pre-built binaries either as big ZIP archive or as small Tar XZ archive. They are built with MSYS2 and must be unpacked under /usr/local such that the complete installation path is /usr/local/llvm-3.8. I assume that an MSYS2 installation is not even necessary, but I have not tested it.

I do not have an idea of the installation procedure on Mac. However, LLVM is developed by Apple thus installation should not be overly complicated.

You may also build LLVM yourself from sources. I suggest that you configure the build with

cmake -G "Unix Makefiles" -DCMAKE_INSTALL_PREFIX=/usr/local/llvm-3.8 -DLLVM_BUILD_LLVM_DYLIB=ON -DLLVM_LINK_LLVM_DYLIB=ON -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_ASSERTIONS=ON /your/path/to/llvm-3.8.1.src/

The default configuration is a Debug build that gnerates more than 6 GB of data. By switching to Release build with asserts and dynamic linking as above, it will only build about 600 MB of data. I think that for our needs you even only need the content of the include directory and the lib/ on Linux or the bin/LLVM.dll on Windows.

Installing llvm-ffi

The first step in the setup of Haskell packages should be

cabal update

in order to fetch the list of all recently updated packages.

The good news is: My packages work with any version of GHC from 7.4 to 8.0. The bad news is: The low-level bindings to LLVM, namely the package llvm-ffi, require extra steps for installation. The ancestor package llvm-base tried to do the configuration automatically using autoconf and some Setup.hs stuff that depended on a particular Cabal version. I replaced this by pkg-config configuration because Cabal supports that optimally. However, in order to work nicely it would require that LLVM comes with a PkgConfig file, which it does not.

It is pretty simple to create such a config file, though. You may install and run my program llvm-pkg-config. It should create a configuration like this one:

Name: LLVM
Description: Low-level Virtual Machine compiler framework
Version: 3.8
Libs: -L/usr/lib/llvm-3.8/lib -lLLVM-3.8
Cflags: -I/usr/lib/llvm-3.8/include -std=c++11

You may just adapt the above content to your needs and write it to /usr/local/lib/pkgconfig/llvm-3.8.pc or to any other location you find appropriate. Then adapt the environment variable PKG_CONFIG_PATH appropriately.

You may now install llvm-ffi:

cabal install -fbuildExamples llvm-ffi

If you run llvm-ffi-example it should emit:


At least, it should not crash.

Installation of synthesizer-llvm

Now installation of the main package should no longer be difficult.

cabal install -fbuildExamples synthesizer-llvm

This should build all necessary packages and some example executables. If you have SoX installed, you may play a MIDI file using

synthi-llvm-render your-music.mid

where your-music.mid is a MIDI file of your choice. The instruments won’t match the ones you expect, but there should be some musical noise. (And due to a SoX bug, playback will silence after about 2 minutes.)

You may also try


This should generate a big file called speedtest.f32 containing a filter effect. You can play it via SoX’ play command:

play -r 44100 speedtest.f32

We will use SoX throughout the tutorial, so please install that, too.

If you are on Linux you should also compile support for Linux’ audio system ALSA.

cabal install -fbuildExamples synthesizer-alsa synthesizer-llvm

This will support live processing of MIDI commands.

On any platform you may also install JACK

cabal install -fbuildExamples -fjack jack synthesizer-llvm

for support of live processing.

Final words

If you have trouble with installation, please contact me via <>.