OS X 10.9 gcc-4.8 unknown symbol `__objc_empty_table`
|Reported by:||jloos||Owned by:|
|Operating System:||MacOS X||Architecture:||x86_64 (amd64)|
|Type of failure:||Compile-time crash||Difficulty:||Unknown|
|Test Case:||Blocked By:|
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 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 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.