These Nix expressions provide an environment for GHC development.
This repository does not contain the GHC sources themselves, so make sure you've cloned that repository first. The directions at https://ghc.dev are an excellent place to start.
Simple usage
Quickstart
To enter an environment without cloning this repository you can run:
nix-shell https://github.com/alpmestan/ghc.nix/archive/master.tar.gz
Building GHC
These commands assume you have cloned this repository
to ~/ghc.nix
. default.nix
has many parameters, all
of them optional. You should take a look at default.nix
for more details.
$ echo "BuildFlavour = quick" > mk/build.mk
$ cat mk/build.mk.sample >> mk/build.mk
$ nix-shell ~/ghc.nix/ --run './boot && ./configure $CONFIGURE_ARGS && make -j4'
# works with --pure too
Note that we passed $CONFIGURE_ARGS
to ./configure
. While this is
technically optional, this argument ensures that configure
knows where the
compiler's dependencies (e.g. gmp
, libnuma
, libdw
) are found, allowing
the compiler to be used even outsite of nix-shell
. For convenience, the
nix-shell
environment also exports a convenience command, configure_ghc
,
which invokes configure
as indicated.
If you are using zsh, you must pass ${=CONFIGURE_ARGS}
instead; otherwise
zsh will escape the spaces in $CONFIGURE_ARGS
and interpret it as one single
argument. See also https://unix.stackexchange.com/a/19533/61132.
You can alternatively use Hadrian to build GHC:
$ nix-shell ~/ghc.nix/
# from the nix shell:
$ ./boot && ./configure $CONFIGURE_ARGS # In zsh, use ${=CONFIGURE_ARGS}
# example hadrian command: use 4 cores, build a 'quickest' flavoured GHC
# and place all the build artifacts under ./_mybuild/.
$ hadrian/build -j4 --flavour=quickest --build-root=_mybuild
# if you have never used cabal-install on your machine, you will likely
# need to run the following before the hadrian command:
$ cabal update
Or when you want to let nix fetch Hadrian dependencies enter the shell with
$ nix-shell ~/ghc.nix/ --arg withHadrianDeps true
ghcide
Using You can also use ghc.nix
to provide the right version of ghcide
if you
want to use ghcide
whilst developing on GHC. In order to do so, pass the withIde
argument to your nix-shell
invocation.
nix-shell ~/.ghc.nix --arg withIde true
./validate
Running $ nix-shell ~/ghc.nix/ --pure --run 'THREADS=4 ./validate'
See other flags of validate
by invoking ./validate --help
or just by reading its source code. Note that ./validate --slow
builds the compiler in debug mode which has the side-effect of disabling performance tests.
Building and running for i686-linux from x86_64-linux
It's trivial!
$ nix-shell ~/ghc.nix/ --arg nixpkgs '(import <nixpkgs> {}).pkgsi686Linux'
Cachix
There is a Cachix cache (ghc-nix) which is filled by our CI. To use it, run the following command and follow the instructions:
cachix use ghc-nix
The cache contains Linux x64 binaries of all packages that are used during a default build (i.e. a build without any overridden arguments).
ghc.nix
Updating We are using niv for dependency management of ghc.nix
.
Our main external dependencies are nixpkgs
and ghcide-nix
.
To update the revisions of those dependencies, you need to run:
$ niv update
If you want to only update a single dependency, e.g. ghcide, you may run
$ niv update ghcide-nix
If you need to switch the branch of nixpkgs, you need to run niv update nixpkgs -b <branch-name>
.
As an example, assume you want to use the nightly nixpkgs channel, you run:
$ niv update nixpkgs -b nixos-unstable
After a brief wait time, the revision is updated.
TODO
- We currently can't just invoke
nix-build
(#1) - We do not support all the cross compilation machinery that
head.nix
from nixpkgs supports.