[GHC] #10244: "memory barriers unimplemented on this architecture" on ARM pre-ARMv7

[GHC]

#10244: "memory barriers unimplemented on this architecture" on ARM pre-ARMv7
-------------------------------------+-------------------------------------
              Reporter:  rwbarton    |             Owner:  simonmar
                  Type:  bug         |            Status:  new
              Priority:  normal      |         Milestone:
             Component:  Runtime     |           Version:  7.10.1
  System                             |  Operating System:  Unknown/Multiple
              Keywords:              |   Type of failure:  Building GHC
          Architecture:  arm         |  failed
             Test Case:              |        Blocked By:
              Blocking:              |   Related Tickets:
Differential Revisions:              |
-------------------------------------+-------------------------------------
 Phab:D33 broke the build on ARM pre-ARMv7, because there is no definition
 of `store_load_barrier` or `load_load_barrier` for those platforms.
 (Granted, the old fall-back behavior of doing nothing was almost certainly
 incorrect.)

 I don't know whether we need CPU-level barriers here, or whether they are
 available. At a minimum, we need a compiler-level barrier. If we need a
 CPU-level barrier and it isn't provided by the instruction set, then I
 guess we should disable SMP for these platforms in `mk/config.mk.in`.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10244>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler