I have a project that involves building a shared library containing code
generated by GHC and exposed using the foreign function interface to
other C programs that link against it. I'm able to build a functioning
library without issue on 32bit x86 systems using GHC 6.8.2 and 6.12.3.
When I try to build on a 64bit x86 system I get a relocation error that
advises I include -fPIC. Including -fPIC does not help though. I'm
wondering if I'm either doing something wrong or if this could be a
problem with GHC.
I've created and attached a small example that illustrates this issue.
When building on 64bit x86 with GHC 7.0.1 and -fPIC and -dynamic I get
the following error. (Similar with GHC 6.12.3)
/usr/bin/ld: CLibrary.o: relocation R_X86_64_PC32 against
`CLibrary_testFunctionCWrapper_srt' can not be used when making a shared
object; recompile with -fPIC
/usr/bin/ld: final link failed: Bad value
When building on 64bit x86 with GHC 7.0.1 and -fPIC and without -dynamic
I get the following error (Similar with GHC 6.12.3 and 6.8.2)
/usr/bin/ld:
/home/CIRG/ew/local/lib/ghc-7.0.1/base-4.3.0.0/libHSbase-4.3.0.0.a(Base__1.o):
relocation R_X86_64_32S against `a local symbol' can not be used when
making a shared object; recompile with -fPIC
/home/CIRG/ew/local/lib/ghc-7.0.1/base-4.3.0.0/libHSbase-4.3.0.0.a:
could not read symbols: Bad value
When building on 32bit x86 with GHC 6.12.3 I get no error regardless of
-fPIC or -dynamic.
When building on 32bit x86 with GHC 6.8.2 I get no error regardless of
-fPIC and without -dynamic.
Any advice would be appreciated! Thanks.
module CLibrary where
import Foreign.C.Types
import Foreign.C.String
import Foreign.Marshal.Alloc
import Foreign.Marshal.Array
import Foreign.Ptr
import Foreign.Storable
foreign export ccall "testFunction" testFunctionCWrapper :: CString -> IO (Ptr
CString)
testFunctionCWrapper :: CString -> IO (Ptr CString)
testFunctionCWrapper cs = do
input <- peekCString cs
output1 <- newCString "hello world"
output2 <- newCString input
newArray [output1, output2]
LIB=test.so
OPTIONS=-fPIC -XForeignFunctionInterface -no-hs-main -optl -shared -rdynamic
#OPTIONS=-dynamic -fPIC -XForeignFunctionInterface -no-hs-main -optl -shared
-rdynamic
GHC=ghc
#GHC=/home/CIRG/ew/local/bin/ghc
all:
$(GHC) $(OPTIONS) --make CLibrary -o $(LIB)
clean:
rm -rf *.hi *.o CLibrary_stub.c CLibrary_stub.h
pretty: clean
rm -rf *~ $(LIB)
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