Re: [GHC] #9332: Memory blowing up for strict sum/strict foldl in ghci

19 Jul 2014

      #9332: Memory blowing up for strict sum/strict foldl in ghci
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              Reporter:              |             Owner:
  artella.coding                     |            Status:  closed
                  Type:  bug         |         Milestone:  7.8.4
              Priority:  high        |           Version:  7.8.3
             Component:  GHCi        |          Keywords:  ghci, strict,
            Resolution:  fixed       |  memory
Differential Revisions:              |  Operating System:  Linux
          Architecture:  x86_64      |   Type of failure:  Runtime
  (amd64)                            |  performance bug
            Difficulty:  Unknown     |         Test Case:
            Blocked By:              |          Blocking:
       Related Tickets:              |
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Comment (by artella.coding):

 OK things are a bit clearer now, but I am still not certain as to whether
 it is a bug or not. If we have :

 {{{
 --Test.hs
 module Main (main) where
 import Data.List

 longList::[Int]
 longList = [1 .. ]

 result :: Int
 result = foldl' (+) 0 $ takeWhile (< 10000000) longList

 main = do
   print $ result
 }}}

 Now if we do :

 a)First clean all .o and .hi files.
 b)Now compile as "ghc Test". This creates .hi and .o files.
 c)Now load into ghci via "ghci Test"
 d)"longList" is in scope. Therefore unsurprisingly running main blows up.

 Now if we do the following :

 a)Clean all .o and .hi files.
 b)Load into ghci via "ghci -fobject-code Test"
 c)Now "longList" is not in scope. This time running main does not blow up.

 I think that Orjan was trying to explain this in
 http://stackoverflow.com/a/24840786/917635

--
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9332#comment:7
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