[GHC] #9909: Linker error (TemplateHaskell + HPC?)

[GHC]

#9909: Linker error (TemplateHaskell + HPC?)
-------------------------------------+-------------------------------------
       Reporter:  dcturner           |                   Owner:
           Type:  bug                |                  Status:  new
       Priority:  normal             |               Milestone:
      Component:  Compiler           |                 Version:  7.8.3
       Keywords:                     |        Operating System:
   Architecture:  Unknown/Multiple   |  Unknown/Multiple
     Difficulty:  Unknown            |         Type of failure:
     Blocked By:                     |  None/Unknown
Related Tickets:                     |               Test Case:
                                     |                Blocking:
                                     |  Differential Revisions:
-------------------------------------+-------------------------------------
 I'm getting the following error message when compiling a Yesod
 application (which uses Template Haskell rather a lot) with -fhpc:

 {{{
 /usr/bin/ld: ./Foundation.dyn_o: relocation R_X86_64_PC32 against
 undefined symbol `_hpc_tickboxes_Settings_hpc' can not be used when making
 a shared object; recompile with -fPIC
 }}}

 Steps to reproduce:

 1. Run `yesod init` to make a new scaffold. Call it `testsite` and
 select `simple` for no database.
 2. Run:

 {{{
 cd testsite
 ghc --make app/main.hs  -XTemplateHaskell -XCPP -XOverloadedStrings
 -XMultiParamTypeClasses -XTypeFamilies -XQuasiQuotes -fhpc -O1
 }}}

 Running the `ghc` line again completes successfully.

 It seems that there is a missing `./Settings.dyn_o` in the `gcc` command
 line that `ghc` calls, the first time through. It's there the second
 time so the link succeeds. No idea what that might mean.

 It's not a problem at `-O0`.

 I'm using 7.8.3 so this might be fixed now.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9909>
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