[GHC] #14931: Segfault compiling files with -fprof-all

16 Mar 2018


      #14931: Segfault compiling files with -fprof-all
-------------------------------------+-------------------------------------
           Reporter:  RyanGlScott    |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Profiling      |           Version:  8.4.1
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  Compile-time
  Unknown/Multiple                   |  crash or panic
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 Originally noticed [https://github.com/llvm-hs/llvm-
 hs/issues/86#issuecomment-373710312 here]. Take the following two files:

 {{{#!hs
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE FunctionalDependencies #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE UndecidableInstances #-}
 module State (MonadState(..), Lazy.evalState) where

 import qualified Control.Monad.Trans.State.Lazy as Lazy (StateT, get, put,
 evalState)

 class Monad m => MonadState s m | m -> s where
     get :: m s
     put :: s -> m ()

 instance Monad m => MonadState s (Lazy.StateT s m) where
     get = Lazy.get
     put = Lazy.put
 }}}
 {{{#!hs
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE TemplateHaskell #-}
 module Bug where

 import Prelude (Int, IO, Bool(..), Num(..), Monad(..), not, print)
 import qualified Language.Haskell.TH.Syntax as TH
 import State

 wat :: IO ()
 wat = print $(let playGame []     = do
                       (_, score) <- get
                       return score
                   playGame (x:xs) = do
                       (on, score) <- get
                       case x of
                            'a' | on -> put (on, score + 1)
                            'b' | on -> put (on, score - 1)
                            'c'      -> put (not on, score)
                            _        -> put (on, score)
                       playGame xs

                   startState :: (Bool, Int)
                   startState = (False, 0)
               in TH.lift (evalState (playGame "abcaaacbbcabbab")
 startState) )
 }}}

 Compiling them like so leads to a segfault:

 {{{
 $ ~/Software/ghc-8.4.1/bin/ghc -c -O -static -dynamic-too -dynosuf dyn_o
 -dynhisuf dyn_hi State.hs
 $ ~/Software/ghc-8.4.1/bin/ghc -c -O -prof -osuf p_o -hisuf p_hi State.hs
 -fprof-auto
 $ ~/Software/ghc-8.4.1/bin/ghc -c -O -prof -osuf p_o -hisuf p_hi Bug.hs
 Segmentation fault (core dumped)
 }}}

-- 
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14931
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