qprof sends wrong values to addr2line on amd64

Binary package hint: qprof

On my Ubuntu/Hardy-AMD64 on a Pentium D, qprof reports invalid values that do not map to a real location.

Example:

walter@ananas:0:~/src/qprof-0.5.2$ /usr/bin/qprof ./tests/dumb_test
qprof: /home/walter/src/qprof-0.5.2/tests/dumb_test: 16 samples, 16 counts
[0x7fff3b347858] 16 (100%)

That should be:

walter@ananas:0:~/src/qprof-0.5.2$ /usr/local/bin/qprof ./tests/dumb_test
qprof: /home/walter/src/qprof-0.5.2/tests/dumb_test: 16 samples, 16 counts
main 16 (100%)

I've played around a bit with the sigcontext pointer, and it seems like I got it right by replacing (&si) with (scv + 40). I have too little knowledge of CPUs, ABI's and binary files in general to know why scv+40 is right, but in my preliminary tests, I got valuable output similar to that which I get on a i686 system (also Hardy).

Attached are:
qprof_bug_fix.patch - The one line patch that works for me
qprof_bug_cpuinfo.txt - cat /proc/cpuinfo
qprof_bug_gcc_dM_E.txt - gcc -dM -E - </dev/null

walter@ananas:0:~/src/qprof-0.5.2$ uname -a
Linux ananas.wjd.nu 2.6.24-23-generic #1 SMP Wed Apr 1 21:43:24 UTC 2009 x86_64 GNU/Linux
walter@ananas:0:~/src/qprof-0.5.2$ dpkg -l qprof | grep ii
ii qprof 0.5.2-5 Profiling utilities for Linux

That's about all the information I can think of. Please let me know if there's anything I can assist with.

Greetings,
Walter Doekes