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The GHC Team

GHC has an enormous "surface area", and has grown way beyond the capacity of any individual, or even research group, to maintain and develop. Its continued success is built on the active contributions of a large group of highly talented people, who take responsiblity for significant parts of the system. This page summarises who does what.

See also the working on GHC page.

What it means to "own" part of GHC

What does it mean to be the "owner" of a chunk of GHC, say X?

  • Being the owner of a chunk of GHC is a public service. Everyone else gives the owner lots of kudos for looking after X on our behalf.
  • The owner is the first port of call for guidance about how X works.
  • If you want to work on X, it makes sense to talk to the owner first, to see what he or she is planning, and to debate the design.
  • The owner feels a sense of ownership. That means taking responsibility for keeping it clean and beautiful, and refactoring when necessary.
  • The owner can't be expected to fix every buglet, but feels a sense of responsibility to make sure that serious bugs are fixed.
  • Owners are expected to step down if they are no longer able to make the time commitment required.

Ownership means being the "first among equals" rather than "having exclusive control":

  • It does not mean that everyone else can relax and say "oh Fred is dealing with X". Fred needs help!
  • It does not mean that no changes can happen to X without the owner's say-so, most especially if the owner becomes hard to contact.
  • It does not mean that the owner can make decisions that the community disagrees with. Being willing to roll up your sleeves lends weight to your voice, but owners should seek consensus for contentious issues.

When contacting an owner, always cc, so that others can contribute. It's a community thing.

The GHC repository is held on a machine called "Abott".

Current Owners

This section lists the current owners of various parts of GHC. If you'd like to take responsibility for something, tell us (on the ghc-devs list). Ideally all parts of GHC should have someone who claims responsibility for it. Although some of these parts are cross-cutting concerns, we also list the directories in the GHC source tree that are most directly implicated.

  • Overall guidance and advice (the GHC Tsars)
    • Simon Peyton Jones, Simon Marlow
  • Build system, release process.
    • Ian Lynagh
    • Directories: mk/, distrib/, ghc-tarballs/, rules/, utils/, compiler/main

  • Foreign function interface (FFI)
    • Ian Lynagh
    • Directories: libffi/
  • The main HsSyn data type
    • Simon Peyton Jones
    • Directories: compiler/hsSyn
  • Renamer
    • Simon Peyton Jones
    • Directories: compiler/rename
  • Type inference and interface files
    • Simon Peyton Jones
    • Directories: compiler/types, compiler/typecheck, compiler/iface

  • Core, System FC, Simplifier and other optimisations on Core
    • Simon Peyton Jones
    • Directories: compiler/coreSyn, compiler/deSugar, compiler/simplCore, compiler/specialise, compiler/stranal
  • Native code generator, register allocation
    • Ben Lippmeier, Simon Marlow
    • Directories: compiler/nativeGen
  • LLVM code generation
    • David Terei
    • Directories: compiler/llvmGen
  • Runtime system, SMP support
    • Simon Marlow
    • Directories: rts/, includes/
  • GHCi, and debugger
    • Needs love
    • Directories: compiler/ghci, ghc/, driver/.
  • Template Haskell
    • Simon Peyton Jones
    • Directories: libraries/template-haskell, plus bits scattered over compiler/
  • Data Parallel Haskell
    • Manuel Chakravarty, Ben Lippmeier
    • Directories: compiler/vectorise
  • Safe Haskell
    • David Terei
    • Directories: compiler/basicTypes, compiler/deSugar, compiler/ghci, compiler/hsSyn, compiler/iface, compiler/main, compiler/parser, compiler/rename, compiler/typecheck, compiler/types
  • Cloud Haskell
    • Tim Watson, Jeff Epstein
    • Code at:
  • Performance Tsars
    • Johan Tibell, David Terei, Bryan O'Sullivan
    • Directories: nofib/

Cross-cutting compiler directories: parser/, prelude/, profiling/, utils/.


Some libraries are very closely coupled to GHC, come with any GHC installation, and are properly considered part of GHC. (This list is very incomplete.)

  • IO Manager
    • Johan Tibell, Andreas Voellmy

Current Committers

The following is a list of all the people who are authorized to commit to GHC. (We've also had many wonderful people in the past who are listed at the bottom of this page.)

For more details, see Committers?.

  • Andreas Voellmy
  • Austin Seipp
  • Ben Lippmeier
  • David Terei
  • David Waern
  • Dimitrios Vytiniotis
  • Duncan Coutts
  • Edsko de Vries
  • Erik de Castro Lopo
  • Edward Yang
  • Geoffrey Mainland
  • Gabor Greif
  • Herbert Valerio Riedel
  • Ian Lynagh
  • Iavor Diatchki
  • Ilya Sergey
  • Johan Tibell
  • José Pedro Magalhães
  • Jan Stolarek
  • Manuel Chakravarty
  • Max Bolingbroke
  • Nicolas Frisby
  • Páli Gábor János
  • Paolo Capriotti
  • Richard Eisenberg
  • Roman Leshchinskiy
  • Ross Patterson
  • Ryan Newton
  • Simon Hengel
  • Simon Marlow
  • Simon Peyton Jones
  • Thomas Schilling

Platform maintainers

The following table lists the people who have generously agreed to be responsible for the GHC port to a particular platform, or to produce binary packages for a certain platform.

For a full description of GHC support for various platforms, see Platforms.

  • x86
    • Windows (targetting mingw): Sigbjorn Finne
    • Windows (targetting Cygwin): Position open; port bitrotted
    • Linux (generic): Simon Marlow, Simon Peyton Jones
    • FreeBSD/i386: FreeBSD Haskell Team
    • OpenBSD: Matthias Kilian
    • SuSE Linux/x86 packages: Sven Panne,Ralf Hinze
    • Gentoo Linux/x86 packages: Gentoo Haskell team
    • Debian GNU/Linux/x86 packages: Kari Pahula
    • MacOS X: Manuel Chakravarty
    • Fedora packages: Fedora Haskell SIG
  • PowerPC
    • AIX: Audrey Tang
    • Linux: Ryan Lortie, Erik de Castro Lopo
    • Gentoo Linux packages (32 and 64bit): Gentoo Haskell team
    • Debian GNU/Linux/powerpc packages: Kari Pahula
    • MacOS X: Wolfgang Thaller,Thorkil Naur
    • Fedora packages: Fedora Haskell SIG (until F12)
  • Sparc
    • Solaris: Position open
    • Linux: Position open
    • Gentoo Linux packages: Gentoo Haskell team
    • Debian GNU/Linux/sparc packages: Kari Pahula
  • x86_64
    • Linux: Simon Marlow
    • Gentoo Linux packages: Gentoo Haskell team
    • Debian GNU/Linux/amd64 packages: Kari Pahula
    • FreeBSD/amd64: FreeBSD Haskell Team
    • OpenBSD: Matthias Kilian
    • Fedora packages: Fedora Haskell SIG
  • Mips64
    • Irix: Don Stewart
  • Mips
    • Debian GNU/Linux/mips packages: Kari Pahula
  • Mipsel
    • Debian GNU/Linux/mipsel packages: Kari Pahula
  • IA-64
    • Linux: Matt Chapman
    • Gentoo Linux packages: Gentoo Haskell team
    • Debian GNU/Linux/ia64 packages: Kari Pahula
  • Alpha
    • Dec OSF: Ken Shan
    • Linux: Position open.
    • Gentoo Linux packages: Gentoo Haskell team
    • Debian GNU/Linux/alpha packages: Kari Pahula
  • HPPA
    • Gentoo Linux packages: Gentoo Haskell team
    • Debian GNU/Linux/hppa packages: Kari Pahula
  • S/390
    • Debian GNU/Linux/s390 packages: Kari Pahula
  • Arm
    • Debian GNU/Linux/arm packages: Kari Pahula

Past contributors

These people have contributed to GHC and its core libraries in the past, in various wonderful ways:

Krasimir Angelov, Lennart Augustsson (including work on many core libraries, originally for hbc), Jean-Philippe Bernardy (Maintenance of Data.*Map/*Set libraries), Jost Berthold (Parallel Haskell: Eden), Bjorn Bringert, Sebastien Carlier, Andrew Cheadle, Tim Chevalier (External Core, strictness analysis, ticky-ticky profiling), Duncan Coutts (parallel profiling, package system), Iavor S Diatchki (type-level literals), Richard Eisenberg, Sigbjorn Finne, Andy Gill (Haskell Program Coverage), Kevin Glynn, John Goerzen, Cordy Hall, Kevin Hammond, Tim Harris (Transactional memory, concurrency), David Himmelstrup (GHC developer), José Iborra (GHCi Debugger), Isaac Jones (Cabal, libraries), Ralf Laemmel, Roman Leshchinskiy, Andres Loeh, Hans Wolfgang Loidl, John Launchbury, Ryan Lortie (PowerPC Linux port, packages), Jim Mattson, John Meacham, Darren Moffat, Nick Nethercote, Thomas Nordin, Sven Panne, Sungwoo Park, Will Partain, Ross Paterson, Juan Quintela, Norman Ramsey (a little refactoring in the back end), Alastair Reid, Ben Rudiak-Gould, Patrick Sansom, André Santos, Sean Seefried (Plug-in optimisations (in pluggable-branch)), Julian Seward, Dominic Steinitz (Cryptographic library), Don Stewart (OpenBSD support), Volker Stolz, Josef Svenningsson, Audrey Tang (Perl-related tools (ghc-asm, ghc-split), AIX port), Dinko Tenev, Wolfgang Thaller (Darwin/Mac OS X ports, position-independent code generation), Mike Thomas, Reuben Thomas, Christopher D. Thompson-Walsh, Dylan Thurston, Phil Trinder, Mark Tullsen, David N Turner, Philip Wadler, David Waern (Haddock comment support), Malcolm Wallace, Michael Weber, Ashley Yakeley (Time library), N. Xu.