The GHC reading list

Suppose you want to start contributing to GHC: what should you read by way of background? Here is an annotated list. Please add to it as you come across useful material.

You can ask questions on ghc-devs@haskell.org. People are friendly. See also working on GHC and GHC contributors.

General background

• The GHC Commentary is a Wiki that describes GHC's implementation. It is a Wiki. That means that you can, and should, fix errors and write new chapters.

•  The Glasgow Haskell Compiler, in  The Architecture of Open Source Applications, Volume II, ed Brown & Wilson. This paper gives an up to date (2012) technical overview of GHC.

• Simon PJ's  home page and  publications page have lots of relevant papers. Some key ones appear below but not all.

• Simon PJ's books:
  •  The Implementation of Functional Programming Languages
  •  Implementing Functional Languages: a tutorial give useful general background. They are not GHC-specific at all, but they have lots of information about functional-language compilers.

Types and type inference

•  Modular type inference with local assumptions, Simon Peyton Jones, Dimitrios Vytiniotis, Tom Schrijvers, Martin Suzmann, Journal of Functional Programming, 2011. This epic 83-page JFP paper brings together, in a single uniform framework, a series of our earlier papers on type inference for type systems involving local constraints, including GADTs and indexed type families.

•  Papers about type equalities in GHC's intermediate language
  • Equality proofs and deferred type errors, Simon Peyton Jones, Dimitrios Vytiniotis and Pedro Magalhaes (ICFP 2012). An exploration of what happens when you take equality proofs seriously in a compiler.
  • Giving Haskell a promotion, Brent Yorgey, Stepanie Weirich, Julien Cretin, Simon Peyton Jones, and Dimitrios Vytiniotis (TLDI 2012). How to (a) add kind polymorphism and (b) promote data types to become data kinds.
  • System F with Type Equality Coercions, Martin Sulzmann, Manuel Chakravarty, and Simon Peyton Jones (TLDI 2007). The first paper about System FC.

•  Unboxed values as first class citizens, SL Peyton Jones and J Launchbury, Functional Programming Languages and Computer Architecture (FPCA'91), Boston, LNCS 523, Springer Verlag, Sept 1991, pp636-666. How unboxed data types work in GHC.

Please add: System FC, GADTs, kind polymorphism etc

Optimisations

•  A transformation-based optimiser for Haskell, SL Peyton Jones and A Santos, Science of Computer Programming 32(1-3), pp3-47, September 1998. Gives an overview of many of the transformations GHC does on Core. Andre's  PhD thesis gives more details.

•  Secrets of the GHC inliner, Simon Peyton Jones and Simon Marlow, Journal of Functional Programming 12(4), July 2002, pp393-434. Describes how the Simplifier does inlining.

•  A short cut to deforestation, A Gill, SL Peyton Jones, J Launchbury, Proc Functional Programming Languages and Computer Architecture (FPCA'93), Copenhagen, June 1993, pp223-232. The famous foldr/build rule. Andy's  PhD thesis has more.

•  Playing by the rules: rewriting as a practical optimisation technique in GHC, Simon Peyton Jones, Andrew Tolmach and Tony Hoare, Haskell Workshop 2001. Describes how RULES work, which are heavily used in GHC.

•  Call-pattern Specialisation for Haskell Programs, Simon Peyton Jones, ICFP 2007. Describe the specialisation optimiser.

•  Let-floating: moving bindings to give faster programs, Simon Peyton Jones, Will Partain, and Andre Santos, ICFP 1996. Describe the let floating and full laziness optimisation passes.

Data Parallel Haskell

•  Data Parallel Haskell: a status report, Manuel M. T. Chakravarty, Roman Leshchinskiy, Simon Peyton Jones, Gabriele Keller, and Simon Marlow. , DAMP 2007: Workshop on Declarative Aspects of Multicore Programming, 2007

•  Harnessing the Multicores: Nested Data Parallelism in Haskell, Simon Peyton Jones, Roman Leshchinskiy, Gabriele Keller, and Manuel M. T. Chakravarty , IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2008), IBFI, Schloss Dagstuhl, 2008.

•  Vectorisation Avoidance, Gabriele Keller, Manuel M. T. Chakravarty, Roman Leshchinskiy, Ben Lippmeier, and Simon Peyton Jones, Proceedings of ACM SIGPLAN Haskell Symposium 2012, ACM Press, 2012.

•  Work Efficient Higher-Order Vectorisation, Ben Lippmeier, Manuel M. T. Chakravarty, Gabriele Keller, Roman Leshchinskiy, and Simon Peyton Jones, The 17th ACM SIGPLAN International Conference on Functional Programming, ACM Press, 2012

Intermediate Representation of GHC (Core & Related)

• An External Representation for the GHC Core Language Gives an overview of the semantics and syntax of Core, GHC's internal intermediate representation for Haskell that most of the optimisation work is done on. A good language to understand when starting with GHC.

• Unboxed Values as First-Class Citizens, Simon L Peyton Jones and John Launchbury, Conference on Functional Programming Languages and Computer Architecture, September 1991. Describe the design of GHC language and internals for handling machine values and boxing / unboxing them as lazy values.

Code generation and virtual machine

•  How to make a fast curry: push/enter vs eval/apply, Simon Marlow and Simon Peyton Jones, International Conference on Functional Programming, Snowbird, Sept 2004, pp4-15.

•  Faster laziness using dynamic pointer tagging (Simon Marlow, Alexey Rodriguez Yakushev, Simon Peyton Jones) In ICFP '07: Proceedings of the ACM SIGPLAN international conference on Functional programming, Freiburg, Germany, ACM Press, October 2007

•  Implementing lazy functional languages on stock hardware: the Spineless Tagless G-machine, SL Peyton Jones, Journal of Functional Programming 2(2), Apr 1992, pp127-202. The original STG paper but still highly relevant.

Please add: Hoopl, C--.

IO and Related

•  Tackling the awkward squad: monadic input/output, concurrency, exceptions, and foreign-language calls in Haskell, Simon Peyton Jones. Deals with the incarnation of IO in Haskell and GHC. The history getting to monads, handling exceptions and handling concurrency.

• Imperative Functional Programming, Simon Peyton Jones, Philip Wadler. POPL, Jan 1993, pp71-84. Presents Monads as a way of implementing IO in Haskell.

• Concurrent Haskell, Simon Peyton Jones, Andrew Gordon, Sigbjorn Finne. Deals with the various concurrency constructs in GHC and the Haskell language. E.g., MVars.

The run-time system and garbage collector

•  Runtime Support for Multicore Haskell (Simon Marlow, Simon Peyton Jones, Satnam Singh) In ICFP '09: Proceeding of the 14th ACM SIGPLAN International Conference on Functional Programming, Edinburgh, Scotland, August 2009

•  Parallel Generational-Copying Garbage Collection with a Block-Structured Heap (Simon Marlow, Tim Harris, Roshan P. James, Simon Peyton Jones) In ISMM '08: Proceedings of the 7th international symposium on Memory management, Tucson, Arizona, ACM, June 2008

•  Haskell on a Shared-Memory Multiprocessor (Tim Harris, Simon Marlow, Simon Peyton Jones) In Haskell '05: Proceedings of the 2005 ACM SIGPLAN workshop on Haskell, pages 49--61, Tallinn, Estonia, ACM Press, September 2005