[GHC] #9885: ghc-pkg parser eats too much memory

[GHC]

#9885: ghc-pkg parser eats too much memory
-------------------------------------+-------------------------------------
              Reporter:  gnezdo      |            Owner:
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:
             Component:  ghc-pkg     |          Version:  7.8.3
            Resolution:              |         Keywords:
      Operating System:  Linux       |     Architecture:  Unknown/Multiple
       Type of failure:  Runtime     |       Difficulty:  Moderate (less
  performance bug                    |  than a day)
             Test Case:              |       Blocked By:
              Blocking:              |  Related Tickets:
Differential Revisions:              |
-------------------------------------+-------------------------------------

Comment (by gnezdo):

 The most expensive place seems to be this (quoted from .hp file, lightly
 munged):

 {{{
 (953)>>=.\.\.(...)
         >>=.\.\
         >>=.\
         >>=
         many1
         many
         sepBy1
         sepBy
         parseSepList
         parseOptCommaList
         listField
         installedFieldDescrs
         accumFields.setField
         accumFields
         parseFieldsFlat.\
         parseFieldsFlat
         parseInstalledPackageInfo
         parsePackageInfo
         registerPackage
         runit
         main    794023536

 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9885#comment:2>
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