[GHC] #14829: Linking error with ANN pragma

20 Feb 2018

      #14829: Linking error with ANN pragma
-------------------------------------+-------------------------------------
           Reporter:  ehubinette     |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.2.2
           Keywords:                 |  Operating System:  Linux
       Architecture:                 |   Type of failure:  Compile-time
  Unknown/Multiple                   |  crash or panic
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 There seems to be an issue with the ANN pragma, with fatal compilation
 errors.

 To reproduce, setup two modules as such:

 {{{#!hs
 module Test where

 import Weights (Weight(..))

 {-# ANN mainTest (Weight 2) #-}
 mainTest :: IO ()
 mainTest = return ()
 }}}

 {{{#!hs
 {-# LANGUAGE DeriveDataTypeable #-}
 module Weights (Weight(..)) where

 import Data.Data (Data(..))

 newtype Weight = Weight Integer deriving Data
 }}}

 Compiling with GHC version `8.2.2` yields:

 {{{
 λ ghc Test.hs
 [2 of 2] Compiling Test             ( Test.hs, Test.o )
 Test.hs:5:1: fatal:
     cannot find object file ‘./Weights.dyn_o’
     while linking an interpreted expression
 }}}

 The issue persists with `-dynamic-too`:

 {{{
 λ ghc -dynamic-too Test.hs
 [2 of 2] Compiling Test             ( Test.hs, Test.o )
 Test.hs:5:1: fatal:
     cannot find object file ‘./Weights.dyn_o’
     while linking an interpreted expression
 }}}

 ...but disappears with `-dynamic`:

 {{{
 λ ghc -dynamic Test.hs
 [1 of 2] Compiling Weights          ( Weights.hs, Weights.o )
 [2 of 2] Compiling Test             ( Test.hs, Test.o )
 }}}

 Sidenote: with GHC version `8.5.20180219`, the issue disappears with
 `-dynamic-too` ''or'' `-dynamic`:

 {{{
 λ ../../ghc/inplace/bin/ghc-stage2 -dynamic-too Test.hs
 [1 of 2] Compiling Weights          ( Weights.hs, Weights.o )
 [2 of 2] Compiling Test             ( Test.hs, Test.o )
 }}}

 Remove the ANN pragma, and the compiler behaves just fine with both GHC
 versions. Please tell me if I can provide more information. Cheers.

-- 
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14829
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