Compiling DynFlags is jolly slow
|Reported by:||simonpj||Owned by:||simonpj|
|Keywords:||deriving-perf||Cc:||iustin@…, pho@…, dterei, bgamari, asr, gidyn, HairyDude, RyanGlScott|
|Type of failure:||Compile-time performance bug||Test Case:|
|Related Tickets:||Differential Rev(s):|
DynFlags really takes a long time these days.
Ian thinks that it's due to the
Show instances he has added (see attached
Simon M suggests: instead of using
Read/Show, you could generate some code in
mkDerivedConstants to use
Outputable, which should be much smaller and faster.
This ticket is
- To see if we can speed up compilation of
- To check WHY it is so slow. Are there any lessons we can learn or ways to make it compile faster? Is it tickling some asymptotically-bad corner of the compiler?