Hadrian is a new build system for the Glasgow Haskell Compiler. It is based
on Shake and we hope that it will eventually replace the current
make-based build system. If you are curious about the rationale behind the
project and the architecture of the build system you can find more details in
this Haskell Symposium 2016 paper and this Haskell eXchange 2016 talk.
The new build system can work side-by-side with the existing build system. Note, there is
some interaction between them: they put (some) build results in the same directories,
Your first build
Beware, the build system is in the alpha development phase. Things are shaky and often break; there are numerous known issues. Not afraid? Then put on the helmet and follow these steps:
If you have never built GHC before, start with the preparation guide.
This build system is written in Haskell (obviously) and depends on the following Haskell packages, which need to be installed:
ansi-terminal extra mtl quickcheck shake.
Get the sources. It is important for the build system to be in the
hadriandirectory of the GHC source tree:
git clone --recursive git://git.haskell.org/ghc.git cd ghc git clone git://github.com/snowleopard/hadrian
Build GHC using
hadrian/build.bat(on Windows) instead of
make. You might want to enable parallelism with
-j. We will further refer to the build script simply as
build. If you are interested in building in a Cabal sandbox or using Stack, have a look at
build.stack.shscripts. Also see instructions for building GHC on Windows using Stack. Note, Hadrian runs the
configurescripts automatically on the first build, so that you don't need to. Use
--skip-configureto suppress this behaviour (see overview of command line flags below).
Using the build system
Once your first build is successful, simply run
build to rebuild. Build results
are placed into
Command line flags
In addition to standard Shake flags (try
--help), the build system
currently supports several others:
--flavour=FLAVOUR: choose a build flavour. The following settings are currently supported:
devel2. As an example, the
-O0flag to all GHC invocations and builds libraries only in the
vanillaway, which speeds up builds by 3-4x. Build flavours are documented here.
--haddock: build Haddock documentation.
--integer-simple: build GHC using the
integer-simpleinteger library (instead of
--progress-colour=MODE: choose whether to use colours when printing build progress info. There are three settings:
never(do not use colours),
auto(attempt to detect whether the console supports colours; this is the default setting), and
--progress-info=STYLE: choose how build progress info is printed. There are four settings:
brief(one line per build command),
normal(typically a box per build command; this is the default setting), and
normaljust won't do).
--skip-configure: use this flag to suppress the default behaviour of Hadrian that runs the
configurescripts automatically if need be, so that you don't have to remember to run them manually. With
--skip-configureyou will need to manually run:
./boot ./configure # On Windows run ./configure --enable-tarballs-autodownload
as you normally do when using
make. Beware, by default Hadrian may do network I/O on Windows to download necessary tarballs, which may sometimes be undesirable;
--skip-configureis your friend in such cases.
--split-objects: generate split objects, which are switched off by default. Due to a GHC bug, you need a full clean rebuild when using this flag.
--verbose: run Hadrian in verbose mode. In particular this prints diagnostic messages by Shake oracles.
make-based build system uses
mk/build.mk to specify user build settings. We
hadrian/UserSettings.hs for the same purpose, see documentation.
Clean and full rebuild
build cleanremoves all build artefacts.
build -Bforces Shake to rerun all rules, even if the previous build results are are still up-to-date.
To build a GHC source distribution tarball, run Hadrian with the
build validateruns GHC tests by simply executing
testsuite/testsdirectory. This can be used instead of
sh validate --fast --no-cleanin the existing build system. Note: this will rebuild Stage2 GHC,
hpcif they are out of date.
build testruns GHC tests by calling the
testsuite/driver/runtests.pypython script with appropriate flags. The current implementation is limited and cannot replace the
validatescript (see #187).
build selftestruns tests of the build system. Current test coverage is close to zero (see #197).
The new build system still lacks many important features:
- There is currently no support for the
dynamicbuild way: #4.
- Validation is not implemented: #187.
- Only HTML Haddock documentation is supported (use
- Not all modes of the old build system are supported, e.g. #250.
- Cross-compilation is not implemented: #177.
- There is no support for installation or binary distribution: #219.
Check out milestones to see when we hope to resolve the above limitations.
How to contribute
The best way to contribute is to try the new build system, report the issues you found, and attempt to fix them. Please note: the codebase is very unstable at present and we expect a lot of further refactoring. If you would like to work on a particular issue, please let everyone know by adding a comment about this. The issues that are currently on the critical path and therefore require particular attention are listed in #239.
I started this project as part of my 6-month research visit to Microsoft Research Cambridge, which was funded by Newcastle University, EPSRC, and Microsoft Research. I would like to thank Simon Peyton Jones, Neil Mitchell and Simon Marlow for kick-starting the project and for their guidance. Last but not least, big thanks to the project contributors, who helped me endure and enjoy the project.