[GHC] #8490: OS X 10.9 gcc-4.8 unknown symbol `__objc_empty_table`

[GHC]

#8490: OS X 10.9 gcc-4.8 unknown symbol `__objc_empty_table`
----------------------------------+---------------------------------------
       Reporter:  jloos           |             Owner:
           Type:  bug             |            Status:  new
       Priority:  normal          |         Milestone:
      Component:  Compiler        |           Version:  7.6.3
       Keywords:                  |  Operating System:  MacOS X
   Architecture:  x86_64 (amd64)  |   Type of failure:  Compile-time crash
     Difficulty:  Unknown         |         Test Case:
     Blocked By:                  |          Blocking:
Related Tickets:                  |
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 I'm not sure if and how far the ghc-7.6.3 support for OS X is planned, but
 I hit a (possible) linker error with 7.6.3.

 I installed a homebrew gcc-4.8 and changed the ghc config to use it.
 I tried to compile the [http://hackage.haskell.org/package/bindings-GLFW
 bindings-GLFW] package, which was successful, and run `cabal test` on it,
 which fails with following error:


 {{{
 final link ... ghc:
 lookupSymbol failed in relocateSection (relocate external)
 dist/build/HSbindings-GLFW-3.0.3.o: unknown symbol `__objc_empty_vtable'
 linking extra libraries/objects failed
 }}}

 After some research I discovered that this symbol (surely just the first
 which fails) is part of the Objective-C Runtime. The
 /usr/lib/libobjc.dylib exports this symbol.

 In desperation I think I nearly reached the google quota with my research,
 further steps I tried:

 Explicitly link the libobjc lib
 {{{
 ghci -lobjc dist/build/HSbindings-GLFW-3.0.3.o -framework Foundation
 -framework Cocoa -framework IOKit
 }}}
 With the same result as above:

 {{{
 GHCi, version 7.6.3: http://www.haskell.org/ghc/  :? for help
 Loading package ghc-prim ... linking ... done.
 Loading package integer-gmp ... linking ... done.
 Loading package base ... linking ... done.
 Loading object (static) dist/build/HSbindings-GLFW-3.0.3.o ... done
 Loading object (dynamic) /usr/lib/libobjc.dylib ... done
 Loading object (framework) IOKit ... done
 Loading object (framework) Cocoa ... done
 Loading object (framework) Foundation ... done
 final link ... ghc:
 lookupSymbol failed in relocateSection (relocate external)
 dist/build/HSbindings-GLFW-3.0.3.o: unknown symbol `__objc_empty_vtable'
 linking extra libraries/objects failed
 }}}

 I found a [https://github.com/mxcl/homebrew/issues/23687 homebrew issue]
 related to gcc and the Apple switch from libstdc++to libc++ in 10.9 and i
 tried to force linking with explicit `-stdlib=libstdc++` in the cabal file
 (ld-options). But i guess this issue isn't related to the `__objc_***`
 problem, just tried it in desperation.

 Last week I managed to build ghc HEAD with clang bootstrapped with 7.4.6:
 the new linker mechanic seems to resolves this problem in a way (sadly
 some other packages aren't jet compatible with 7.8)

 So I'm not sure if this report is okay, if not, pardon me :)

 I'm aware of the problems with the current ghc-7.6.3 and the the changes
 OS X 10.9 brings with it (according to reddit/haskell cafe). The current
 suggestions is to not use the XCode-5.0.1/clang together with ghc-7.6.3.
 So I tried gcc from homebrew. I know that 7.8 will bring better linker
 capabilities, maybe there are just some flags to fix this specific problem
 with 7.6.3...? I didn't find it. So I thought it's better to report it.

 If further informations are required, I will try to provide them as fast
 as possible but I will have to downgrade to 10.8 tomorrow around 6 a.m.
 UTC.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8490>
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