[GHC] #8951: genSym uses atomic_inc but doesn't link arm_atomic_spin_lock

[GHC]

#8951: genSym uses atomic_inc but doesn't link arm_atomic_spin_lock
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              Reporter:  cjwatson    |            Owner:
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:  7.8.4
             Component:  Build       |          Version:  7.8.1-rc1
  System                             |         Keywords:
            Resolution:              |     Architecture:  arm
      Operating System:  Linux       |       Difficulty:  Unknown
       Type of failure:  Building    |       Blocked By:
  GHC failed                         |  Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by nomeata):

 More info:

 `genSym.c` is linked into libghcHS. It contains code that depends on
 `THREADED_RTS`, but that’s a bit fishy: There is only one `libghcHS` that
 needs to work with both threaded and non-threaded RTSs.

 This code in `compiler/ghc.mk` might be related:
 {{{
 ifeq "$(GhcThreaded)" "YES"
 # We pass THREADED_RTS to the stage2 C files so that cbits/genSym.c will
 bring
 # the threaded version of atomic_inc() into scope.
 compiler_stage2_CONFIGURE_OPTS += --ghc-option=-optc-DTHREADED_RTS
 endif
 }}}

 So one thing I’m trying is to provide the stubs from `rts/OldARMAtomic.c`
 even in the unthreaded RTS. It will be dead code, but at least the linker
 will be happy.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8951#comment:7>
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