On Sun, Jan 20, 2013 at 3:42 AM, Toon Moene <toon@xxxxxxxxx> wrote:
> On 01/20/2013 06:59 AM, Ian Lance Taylor wrote:
>
>> On Sat, Jan 19, 2013 at 10:36 AM, Toon Moene<toon@xxxxxxxxx> wrote:
>>>
>>>
>>> gfortran -g -Wl,-M master.o C_code.o _odb_glue.o -Wl,--start-group
>>> -L/scratch/harmonie/hm_home/trunk/lib/linux.gfortran.mpi/src -lxrd -lxla
>>> -ltfl -ltal -lsur -larp -lald -lbla -lmpa -lmse -lsurfex -lbip -lsat
>>> -luti
>>> -lodb -lodbport -lCCMA -lECMA -Wl,--end-group dummies.o \
>>> -L/scratch/harmonie/hm_home/trunk/lib/linux.gfortran.mpi/src
>>> -lodbdummy -L/scratch/harmonie/hm_home/trunk/lib/linux.gfortran.mpi/src
>>> -lrgb -lgribex -lbufr -L/home/harmonie/grib_api -lgrib_api_f90 -lgrib_api
>>> -lnetcdff -lnetcdf -llapack -lblas -lmpi_f90 -lmpi_f77 -lmpi -lpthread
>>> /home/toon/myglibc/lib/libm.a -o
>>> /scratch/harmonie/hm_home/trunk/lib/linux.gfortran.mpi/src/MASTERODB>
>>> /scratch/harmonie/hm_home/trunk/lib/linux.gfortran.mpi/src/load.map
>>> /usr/bin/ld: dynamic STT_GNU_IFUNC symbol `cos' with pointer equality in
>>> `/home/toon/myglibc/lib/libm.a(s_sin.o)' can not be used when making an
>>> executable; recompile with -fPIE and relink with -pie
>>> collect2: error: ld returned 1 exit status
>>
>>
>> I have no idea why this is happening to you but I can tell you what it
>> means. The symbol "cos" has been defined as an IFUNC symbol in your
>> library. That means that the actual value of "cos" will be selected
>> at runtime, presumably with a version of "cos" that will execute
>> quickly on the processor as detected at runtime. Furthermore, some
>> piece of code in the library is using "cos" in some way other than
>> simply calling it, e.g., taking the address of the function. As it
>> happens, taking the address of an IFUNC function in code not compiled
>> with -fpie or -fpic is problematic, because that code will produce
>> different addresses in different shared libraries, meaning that
>> function pointer equality will not work. The linker is telling you
>> about this problem, and telling you to fix it by recompiling with
>> -fpie.
>
>
> Would placing them in a table like this cause that problem ?
>
> static funcs_t Func[] = {
> /* Compile-time evaluable functions */
> "sin", 1, (void *)sin, NULL, 1, 0,
> "cos", 1, (void *)cos, NULL, 1, 0,
> "tan", 1, (void *)tan, NULL, 1, 0,
Yes, that would count as a reference to an IFUNC function other than
calling it. That code needs to be compiled with -fpie (or -fpic).
Ian
