[GHC] #13252: Perf: Make dep_finsts a map from type family Name to Module

[GHC]

#13252: Perf: Make dep_finsts a map from type family Name to Module
-------------------------------------+-------------------------------------
        Reporter:  ezyang            |                Owner:  (none)
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  8.1
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by Ben Gamari <ben@…>):

 In [changeset:"e5732d2a28dfb8a754ee73e124e3558222a543bb/ghc" e5732d2/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="e5732d2a28dfb8a754ee73e124e3558222a543bb"
 base: Fix hWaitForInput with timeout on POSIX

 This was previously broken (#13252) by
 f46369b8a1bf90a3bdc30f2b566c3a7e03672518, which ported the fdReady
 function from `select` to `poll` and in so doing dropping support for
 timeouts. Unfortunately, while `select` tells us the amount of time not
 slept (on Linux anyways; it turns out this is implementation dependent),
 `poll` does not give us this luxury. Consequently, we manually need to
 track time slept in this case.

 Unfortunately, portably measuring time is hard. Ideally we would use
 `clock_gettime` with the monotonic clock here, but sadly this isn't
 supported on most versions of Darwin. Consequently, we instead use
 `gettimeofday`, running the risk of system time changes messing us up.

 Test Plan: Validate

 Reviewers: simonmar, austin, hvr

 Reviewed By: simonmar

 Subscribers: rwbarton, thomie

 GHC Trac Issues: #13252

 Differential Revision: https://phabricator.haskell.org/D3473
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13252#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler