[GHC] #14379: Regression - GHC 2.8.1 Consumes All Memory On Build (was: GHC 2.8.1 Consumes All Memory On Build)

[GHC]

#14379: Regression - GHC 2.8.1 Consumes All Memory On Build
-------------------------------------+-------------------------------------
        Reporter:  jm4games          |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:
       Component:  Compiler          |              Version:  8.2.1
      Resolution:                    |             Keywords:
Operating System:  Linux             |         Architecture:  x86_64
 Type of failure:  Compile-time      |  (amd64)
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  8.0.2
       Wiki Page:                    |
-------------------------------------+-------------------------------------
Changes (by jm4games):

 * differential:   => 8.0.2


Old description:

> The following code will cause GHC to consume all memory/swap and
> eventually crash.
>
> {{{
> #!div style="font-size: 80%"
> Code highlighting:
>   {{{#!haskell
> module Test.Test where
>
> import Data.Text (Text)
>
> import Data.Monoid ((<>))
> import Data.Vector as V
> import TextShow (showt)
>
> compileTest :: V.Vector (Text, V.Vector (Int, V.Vector a)) -> V.Vector
> (Text, V.Vector (Int, V.Vector a)) -> Either Text ()
> compileTest vecA vecB = V.ifoldl' validateSym (Right ()) vecB
>   where
>     validateSym :: Either Text () -> Int -> (Text, V.Vector (Int,
> V.Vector a)) -> Either Text ()
>     validateSym res iSym (sym, freqs)
>       | Just sym == (fst <$> (vecA V.!? iSym)) = V.ifoldl' validateFreq
> res freqs
>       | otherwise = Left $
>             if iSym < V.length vecA then
>               "Seed data" <> " not found at index [" <> showt iSym <>
> "]."
>               else "No " <> sym <> " at index " <> showt iSym <> "."
>       where
>         validateFreq :: Either Text () -> Int -> (Int, V.Vector a) ->
> Either Text ()
>         validateFreq res2 iFreq (freq, _)
>           | freq == fst (snd (vecA V.! iSym) V.! iFreq) = res2
>           | otherwise = Left $
>                 "Seed data " <> (fst (vecA V.! iSym)) <>
>                 " at frequency " <> showt (fst (snd (vecA V.! iSym) V.!
> iFreq)) <>
>                 " not found at index [" <> showt iSym <> "][" <> showt
> iFreq -- <> "]."
>   }}}
> }}}
>
> NOTE: The snippet is large (and messy) because there seems to be an exact
> sequence of evaluation to causing the out of memory. For example if you
> comment out line 26 (<> showt iFreq) it will allow the code to compile.
> Like wise if I comment out all of line 25 it will compile. I can't seem
> to figure out what exact combination of things causes the issue.
>
> Cabal file (used with stack 1.5.1, resolver: nightly-2017-10-21).
> {{{
> #!div style="font-size: 80%"
> Code highlighting:
>   {{{#!text
> name:                some-test
> version:             0.2.1.0
> build-type:          Simple
> cabal-version:       >= 1.10
>
> library
>   default-language: Haskell2010
>   ghc-options:      -Wall -fwarn-tabs -funbox-strict-fields -fno-warn-
> unused-do-bind -O2
>   ghc-prof-options: -fprof-auto
>
>   exposed-modules:
>     Test.Test
>
>   build-depends:
>     base                    >= 4.9   && < 4.11,
>     text                    >= 1.2,
>     text-show               >= 3.4   && < 3.7,
>     vector                  >= 0.10  && < 0.13
>
>   default-extensions:
>     OverloadedStrings
>   }}}
> }}}

New description:

 The following code will cause GHC to consume all memory/swap and
 eventually crash (a regression from 8.0.2).

 {{{
 #!div style="font-size: 80%"
 Code highlighting:
   {{{#!haskell
 module Test.Test where

 import Data.Text (Text)

 import Data.Monoid ((<>))
 import Data.Vector as V
 import TextShow (showt)

 compileTest :: V.Vector (Text, V.Vector (Int, V.Vector a)) -> V.Vector
 (Text, V.Vector (Int, V.Vector a)) -> Either Text ()
 compileTest vecA vecB = V.ifoldl' validateSym (Right ()) vecB
   where
     validateSym :: Either Text () -> Int -> (Text, V.Vector (Int, V.Vector
 a)) -> Either Text ()
     validateSym res iSym (sym, freqs)
       | Just sym == (fst <$> (vecA V.!? iSym)) = V.ifoldl' validateFreq
 res freqs
       | otherwise = Left $
             if iSym < V.length vecA then
               "Seed data" <> " not found at index [" <> showt iSym <> "]."
               else "No " <> sym <> " at index " <> showt iSym <> "."
       where
         validateFreq :: Either Text () -> Int -> (Int, V.Vector a) ->
 Either Text ()
         validateFreq res2 iFreq (freq, _)
           | freq == fst (snd (vecA V.! iSym) V.! iFreq) = res2
           | otherwise = Left $
                 "Seed data " <> (fst (vecA V.! iSym)) <>
                 " at frequency " <> showt (fst (snd (vecA V.! iSym) V.!
 iFreq)) <>
                 " not found at index [" <> showt iSym <> "][" <> showt
 iFreq -- <> "]."
   }}}
 }}}

 NOTE: The snippet is large (and messy) because there seems to be an exact
 sequence of evaluation to causing the out of memory. For example if you
 comment out line 26 (<> showt iFreq) it will allow the code to compile.
 Like wise if I comment out all of line 25 it will compile. I can't seem to
 figure out what exact combination of things causes the issue.

 Cabal file (used with stack 1.5.1, resolver: nightly-2017-10-21).
 {{{
 #!div style="font-size: 80%"
 Code highlighting:
   {{{#!text
 name:                some-test
 version:             0.2.1.0
 build-type:          Simple
 cabal-version:       >= 1.10

 library
   default-language: Haskell2010
   ghc-options:      -Wall -fwarn-tabs -funbox-strict-fields -fno-warn-
 unused-do-bind -O2
   ghc-prof-options: -fprof-auto

   exposed-modules:
     Test.Test

   build-depends:
     base                    >= 4.9   && < 4.11,
     text                    >= 1.2,
     text-show               >= 3.4   && < 3.7,
     vector                  >= 0.10  && < 0.13

   default-extensions:
     OverloadedStrings
   }}}
 }}}

--

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14379#comment:1>
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