[Libunwind-devel] Libunwind reports the same ip and fp for Fortran code compiled with PGI

[Scott Biersdorff]

Hi,

 

We are looking into an issue with libunwind where it reports the same address as both a IP and FP. This happens with a simple PGI compiled Fortran example. This same example compiled with gfortran reports different addresses:

 

./fortran-standalone.gnu.exe

 ip= 0x0000000000400b19  fp= 0x0000000000400aff

 ip= 0x0000000000400a45  fp= 0x000000000040098d

 ip= 0x0000000000400aa4  fp= 0x0000000000400a82

 ip= 0x0000000000400af8  fp= 0x0000000000400ac4

 ip= 0x00007f43bad53ec5  fp= 0x00007f43bad53dd0

 ip= 0x00000000004008c9  fp= 0x00000000004008a0

 

./fortran-standalone.pgi.exe

 ip= 0x00000000004027eb  fp= 0x00000000004027eb

 ip= 0x00000000004027b0  fp= 0x00000000004027b0

 ip= 0x0000000000402712  fp= 0x0000000000402712

 ip= 0x00000000004026c4  fp= 0x00000000004026c4

 

(Note that both stacks run into strange addresses unknown in the object file; my suspicion is that these are trampoline functions somewhere on stack or heap).

 

I’ve attached the sources and binaries for this example. Can you help us understand what is particular about this binary compiled by PGI that causes this? Is there another way to retrieve the function pointer?

 

Other information:

 

Machine: Linux x86_64

GNU Fortran compiler version 4.8

PGI Fortran compiler version 14.7.

 

Thanks,

 

-          Scott

pgi_fortran_libunwind_bug.tgz
Description: pgi_fortran_libunwind_bug.tgz