[GHC] #15492: Plugin recompilation check fails when profiling is enabled

[GHC]

#15492: Plugin recompilation check fails when profiling is enabled
-------------------------------------+-------------------------------------
           Reporter:  mpickering     |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  highest        |         Milestone:  8.6.1
          Component:  Compiler       |           Version:  8.4.3
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 When compiling with profiling enabled and using a plugin, GHC will panic
 as follows:

 {{{
 ghc: panic! (the 'impossible' happened)
   (GHC version 8.6.1.20180803 for x86_64-unknown-linux):
         mkPluginUsage: no dylibs
   GraphMod
   Call stack:
       CallStack (from HasCallStack):
         callStackDoc, called at compiler/utils/Outputable.hs:1164:37 in
 ghc:Outputable
         pprPanic, called at compiler/deSugar/DsUsage.hs:178:15 in
 ghc:DsUsage
 }}}

 Investigating determines that the following paths are being inspected:

 {{{
 /nix/store/m0ylnbifx5ba1qwi8vzipxq4p7ma3073-graphmod-
 plugin-0.1.0.0/lib/ghc-8.6.1.20180803/x86_64-linux-ghc-8.6.1.20180803
 /libHSgraphmod-plugin-0.1.0.0-3YjHj1EtcCZGtpEicyDU7w_p-
 ghc8.6.1.20180803.so

 /nix/store/q8rg4mca5zqv98arpxd7164pqa72hf1n-ncurses-6.1/lib/libHSgraphmod-
 plugin-0.1.0.0-3YjHj1EtcCZGtpEicyDU7w_p-ghc8.6.1.20180803.so

 /nix/store/hhzvw77vrmn5f506kfyb1yh1sdinkbwf-gmp-6.1.2/lib/libHSgraphmod-
 plugin-0.1.0.0-3YjHj1EtcCZGtpEicyDU7w_p-ghc8.6.1.20180803.so
 }}}

 None of which exist.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15492>
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