Kevan Hashemi wrote:
I just compiled GPC from sources on both 32-bit and 64-bit Linux machines. On both machines, I'm running Scientific Linux 6.4, a derivative of Red Had Linux 6.4. The local C compiler is 4.4.7 in both cases.
On the 32-bit machine, I can compile from Pascal to make objects, and link them with libgpc.a to make a shared library. But on the 64-bit machine I find that I must pass -fPIC to GPC to force it to compile position-independent code for the subsequent link. Even then, libgpc.a is position-dependent, so I can't link it into a shared library. So I edit the GPC build's Makefile:
CFLAGS = -g -O2 -fPIC
Now I build GPC again and re-install. The new libgpc.a is position-independent, and I can make my shared library.
Does anyone know why the default on 64-bit is position-dependent, while on 32-bit it is position-independent?
By default gpc builds position-dependent libgpc. On 32-bit i386 shared libraries may contain position-dependent code, on other platforms, in particular for amd64 you need position-independent code in shared libraries.
If you want shared libgpc, after buildiing gpc do:
cd gcc/p/rts make clean make WITH_SHARED=yes
I do not remember if there is any support for automatically installing libgpc, if needed install resulting libgpc by hand.