Sharing analysis

Simon Peyton-Jones simonpj at
Tue Jan 23 03:38:16 EST 2007

| Does GHC (still) perform sharing analysis as described in 'Once Upon
| a Polymorphic Type' [2] and/or Keith Wansbrough's PhD thesis [1]? If
| so, how does one inspect the results of the analysis?

No, it doesn't.  It was pretty complicated, and the payoff didn't seem to justify it, although the work was extremely interesting and Keith's thesis is great.

That's not to say that there aren't performance gains to be gotten this way. It's a rich design space and we might not have hit the sweet spot.   There is good work going on at Chalmers exploring this space.  E.g. "Polymorphism, Subtyping, Whole Program Analysis and Accurate Data Types in Usage Analysis" which you can find on Josef Svenningsson's home page


| -----Original Message-----
| From: glasgow-haskell-users-bounces at [mailto:glasgow-haskell-users-bounces at] On
| Behalf Of Stefan Holdermans
| Sent: 23 January 2007 07:18
| To: Glasgow Haskell Users
| Cc: keithw at
| Subject: Sharing analysis
| Dear all,
| Thanks in advance,
|    Stefan
| -----
| [1] Keith Wansbrough. Simple Polymorphic Usage Analysis. Ph.D.
| thesis, University of Cambridge, 2002.
| [2] Keith Wansbrough and Simon Peyton Jones. Once upon a polymorphic
| type. In POPL '99, Proceedings of the 26th ACM SIGPLAN-SIGACT
| Symposium on Principles of Programming Languages, January 20-22,
| 1999, San Antonio, TX, pages 15-18. ACM Press, 1999._______________________________________________
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