These documents relate to the latest version of GHC. For earlier versions click the relevant version on the downloads page.

Online Documentation

Dowloadable/Printable Documentation

Here we've collected together lots of documentation and papers that generally describe stuff we've implemented in the compiler.  This is the "how it works" section - for "how to use it" see the compiler documentation above.

All docs are gzipped A4 Postscript unless otherwise specified.

• The Concurrent Haskell Foreign Function Interface.  This document is a draft Haskell addendum that describes GHC's approach to concurrency and its interaction with the FFI and OS threads.
• An External Representation for the GHC Core Language.   This document describes the syntax of GHC Core (.hcr) files, which can be used to feed GHC intermediate code to other (non-GHC) back-end processors.
• Haskell Execution Platform design document. This document describes the design for an integrated compiler/interpreter API for executing Haskell programs, which forms the heart of the combined Hugs/GHC system.
• Run-time System document.  This document (is supposed to) describe the new run-time system in GHC 4.xx.  Be warned that the implementation and this document are evolving in parallel, so they might not be quite in sync.
• The Spineless Tagless G-Machine.  This paper describes the execution model used by GHC.  It is most relevant to GHC up to version 3.xx---in version 4 we made some changes which are described in the RTS document.
• The UsageSP analysis (ghc/compiler/usageSP/) is described in Keith Wansbrough and Simon Peyton Jones, Once Upon a Polymorphic Type, Technical Report TR-1998-19, Department of Computing Science, University of Glasgow, 1998. Conference version Once Upon a Polymorphic Type, in The Twenty-sixth ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages, January 20-22, 1999, San Antonio, Texas.
• GHC's typechecker implementation is described in the paper Type classes in Haskell, CV Hall, K Hammond, SL Peyton Jones, and PL Wadler, European Symposium On Programming, LNCS 788, Springer Verlag, pp. 241-256, April 1994.
• The New GHC/Hugs Runtime System---a summary of the RTS document.
• Asynchronous Exceptions in Haskell
• Lightweight Extensible Records for Haskell
• Derivable Type Classes
• Pattern Guards and Transformational Patterns
• Secrets of the GHC inliner
• Non-stop Haskell the workings of the incremental garbage collector introduced in GHC 4.
• Concurrent Haskell
• Imprecise Exceptions, Co-Inductively
• A semantics for imprecise exceptions
• Imperative Functional Programming
• Lazy Functional State Threads
• Unboxed Values as First-Class Citizens
• Time and Space Profiling for non-stict, higher-order functional programs
• The Glasgow Haskell Compiler - a Technical Overview - from 1992, not entirely relevant any more.
• Adding an Optimisation Pass to the Glasgow Haskell Compiler (Olaf Chitil).  Somewhat out of date.