What?
Dockerfile for building a GHC package for Debian/Ubuntu which supports
statically linking Haskell dependencies into dynamic (e.g. .so) libraries.
Supported GHC versions:
- 8.6.5
How?
If you're on a Debian-based system
Add my Debian repository to your sources, then install the package with apt:
echo deb https://deb.ekblad.cc/ubuntu disco main | sudo tee /etc/apt/sources.list.d/ekblad-cc-disco
wget -O - https://ekblad.cc/key.asc | sudo apt-key add -
sudo apt update
sudo apt install ghc-sd
Otherwise
Install docker, run make, wait. When make is done, you'll find your package
in the deb subdirectory.
To build a shared library with all Haskell dependencies statically linked, use the following GHC flags:
-fPIC -shared -optl-Wl,-Bstatic -lHSrts -lCffi -optl-Wl,-Bdynamic -lrt -lpthread
Unfortunately, cabal has its own ideas about what flags to pass to the linker,
which makes it unable to produce shared libraries with statically linked Haskell
dependencies even when properly setting ld-options and/or ghc-options.
Why?
Because it's nice to be able to distribute Haskell .so files without having to
also distribute the roughly seven million libHSwhatever-x.y.z.so it ends
up depending on with dynamic linking.
With the right flags, this GHC build produces .so files that are only dependent
on the standard system libraries libc, libm, librt and libpthread,
plus libgmp.