This repository is for more experimental work, of production quality, on the middle end and backend of the OCaml compiler. This is also the home of the Flambda 2 optimiser.

The Flambda backend is currently based on OCaml 4.12.0.

The following gives basic instructions for getting set up. Please see HACKING.md for more detailed instructions if you want to develop in this repo. That file also contains instructions for installing the Flambda backend compiler in a way that it can be used to build OPAM packages. (The Flambda backend is expected to appear in the main OPAM repository by the end of 2021.)

Only currently tested on Linux/x86-64 and macOS/x86-64.

One-time setup:

$ opam switch 4.12.0  # or "opam switch create 4.12.0" if you haven't got that switch already
$ eval $(opam env)
$ opam install dune

You probably then want to fork the ocaml-flambda/flambda-backend repo to your own Github org.

Use normal commands to make a branch from the desired upstream branch (typically main), e.g.:

$ git clone https://github.com/ocaml-flambda/flambda-backend
$ cd flambda-backend
$ git checkout -b myfeature origin/main

The Flambda backend tree has to be configured before building. The configure script is not checked in; you have to run autoconf. For example:

$ autoconf
$ ./configure --prefix=/path/to/install/dir --enable-middle-end=closure --with-dune=$DUNE_DIR/dune.exe

You can also specify --enable-middle-end=flambda or --enable-middle-end=flambda2. (The Flambda 2 compiler is not yet ready for production use.)

To build and install the Flambda backend, which produces a compiler installation directory whose layout is compatible with upstream, run:

$ make install