Don’t panic! It’s only an upgrade
Time for another upgrade of my GHC installation. OK, I know I already posted about this twice but yet again the process was different from the previous ones.
My first attempts of installing GHC and the Haskell
Platform a year ago
relied on using packages from my distribution’s repository. This quickly turned
out to be problematic so I decided for a direct installation of the Haskell
Platform. This worked perfectly fine except for the fact that Haskell packages
were installed in different subdirectories of /usr/local, which lead to a bit
of a mess and problems with controlling what is installed where (this is useful
if you want to remove a package). So the second time I was installing Haskell
Platform I was smarter and refined the whole
process. This
time I confined the installation to a single directory so that both GHC and all
the packages are located in a single, easy to find place.
Yesterday I figured out it would be great to get a new version of GHC. GHC 7.6.1
was released on 6th September 2012 and the updated 7.6.2 version is only two
weeks old. While GHC 7.6.1 has been out for over 5 months it is still not part
of the Haskell Platform and it won’t be for the next three
months. That’s
too long a wait for me so I decided to send the Platform to /dev/null and just
install GHC and its environment from scratch.
My plan to install GHC from precompiled binaries went up the spout:
This build requires
libgmp.so.3.
Watwatwat? Now what is that supposed to mean? Previously released binaries
didn’t depend on one particular version of libgmp library. Of course my system
has libgmp.so.10 and any attempt to install an older version results in
breaking package dependencies. I downloaded binaries anyway and tried to run
them:
[killy@xerxes : ~/ghc-7.6.2/ghc/stage2/build/tmp] ./ghc-stage2 --interactive
./ghc-stage2: error while loading shared libraries: libgmp.so.3: cannot open shared object file: No such file or directoryOK, so that requirement is true - you need the exact version of libgmp. So
what now? I know! Compilation from sources! I’ve been hacking on GHC recently so
I already have sources on my drive. Unfortunately it turned out that after
switching GHC repo and all its subrepos to ghc-7.6 branch I get some
compilation errors. I wasn’t in the mood for debugging this so I switched
everything back to master and downloaded the source
snapshot. From now on things are
easy, assuming that you already have an older version of GHC on your
system. After extracting the sources I copied $(TOP)/mk/build.mk.sample to
$(TOP)/mk/build.mk ($(TOP) refers to directory containing GHC sources) and
uncommented the line BuildFlavour = perf-llvm. This gives me fully optimized
build using LLVM. Now the compilation:
perl boot
./configure --prefix=/usr/local/ghc-7.6.2
makeThis will build GHC and prepare it for installation in /usr/local/ghc-7.6.2.
Fully optimized build takes much over an hour on all 4 cores. After the build is
done all one needs to do is run make install as root. At this stage old GHC
can be removed. You of course need to add /usr/``local/``ghc-7.6.2/bin to
PATH environmental variable. As I already have mentioned I have the habit of
installing all the packages system-wide in a single directory. For that I need
to edit /root/.cabal/config file by adding the following entry:
install-dirs global
prefix:/usr/local/ghc-7.6.2All that is left now is installing
cabal-install. Grab the
sources from hackage, extract them and run (as root) sh bootstrap.sh --global
in the source directory. This installs cabal-install with its dependencies. Now
you can start installing other packages that you need (a.k.a. compile the
World).
This completes Yet Another Installation of GHC.