[commit: ghc] ghc-8.2: Optimise common cases of GHC.setProgramDynFlags (7724964)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : ghc-8.2
Link       : http://ghc.haskell.org/trac/ghc/changeset/77249644052c6f3309ff57f7db5c19eb19138d5b/ghc

>---------------------------------------------------------------

commit 77249644052c6f3309ff57f7db5c19eb19138d5b
Author: Simon Marlow <marlowsd at gmail.com>
Date:   Sat Apr 1 11:51:43 2017 -0400

    Optimise common cases of GHC.setProgramDynFlags
    
    * If the package flags haven't changed, don't do initPackages (which
      might take multiple seconds in extreme cases)
    
    * Provide a way to change the log_action without invalidating the
      summary cache.
    
    Test Plan: validate
    
    Reviewers: niteria, bgamari, austin, erikd, ezyang
    
    Reviewed By: bgamari
    
    Subscribers: mpickering, rwbarton, thomie
    
    Differential Revision: https://phabricator.haskell.org/D3392
    
    (cherry picked from commit f7cc1fdebd6aa8b5cb0498ae245a5e8cf3e38f6f)


>---------------------------------------------------------------

77249644052c6f3309ff57f7db5c19eb19138d5b
 compiler/main/DriverPipeline.hs | 10 ++++++-
 compiler/main/DynFlags.hs       | 64 +++++++++++++++++++++++++----------------
 compiler/main/GHC.hs            | 30 +++++++++++++++----
 compiler/main/Packages.hs       | 24 +++++++++++++---
 ghc/GHCi/UI.hs                  |  7 -----
 5 files changed, 94 insertions(+), 41 deletions(-)

Diff suppressed because of size. To see it, use:

    git diff-tree --root --patch-with-stat --no-color --find-copies-harder --ignore-space-at-eol --cc 77249644052c6f3309ff57f7db5c19eb19138d5b