[Discuss-gnuradio] how to debug the SSE assembler files (float_dotprod_sse.S)

[Martin Dvh]

Hi All,

I am writing some new optimized SSE assembler routines.

I am trying to debug them with gdb but are having the following problems.

For some reason gdb doesn't find the source right, or shows the wrong source.

When I set a breakpoint on float_dotprod_sse it thinks it is in file 
../../../../../gnuradio-core/src/lib/general/gr_remez.cc, line 864.
While in fact it is in file 
../../../../../gnuradio-core/src/lib/filter/float_dotprod_sse.S

I added -Wa,--gdwarf2 to CCASFLAGS to enable debugging assembler files.

Also when I step in the assembler routine, it only shows me line line 864 of 
gr_remez.cc as it thinks this is the current sourcefile.
And when I say list float_dotprod_sse it also shows gr_remez.cc

Since I created a segfault in the assembler routine I would really like to step 
through it.

Any ideas what goes wrong here, and how to solve it?

Greetings and thanks,
Martin Dudok van Heel

$ cd trunk
$ mkdir build
$ cd build
$ export CFLAGS="-g -O2  -march=pentium-m -mfpmath=sse -msse -msse2"
$ export CXXFLAGS="-g -O2  -march=pentium-m -mfpmath=sse -msse -msse2"
$ export CCASFLAGS=" -g -O2  -march=pentium-m -mfpmath=sse -msse -msse2 -Wall 
-Wa,--gdwarf2"
$
$ ../configure 2>&1 | tee configure.log
$ make 2>&1 | tee make.log
$ sudo make install 2>&1 | tee make_install.log
$ cd ../gnuradio-core/src/test/.libs

$ gdb test_filter
GNU gdb 6.4.90-debian
Copyright (C) 2006 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i486-linux-gnu"...Using host libthread_db library 
"/lib/tls/i686/cmov/libthread_db.so.1".

(gdb) break main
Breakpoint 1 at 0x8048870: file 
../../../../gnuradio-core/src/tests/test_filter.cc, line 27.
(gdb) list
18       * along with GNU Radio; see the file COPYING.  If not, write to
19       * the Free Software Foundation, Inc., 51 Franklin Street,
20       * Boston, MA 02110-1301, USA.
21       */
22
23      #include <cppunit/TextTestRunner.h>
24      #include <qa_filter.h>
25
26      int
27      main (int argc, char **argv)
(gdb) break float_dotprod_sse
Function "float_dotprod_sse" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y

Breakpoint 2 (float_dotprod_sse) pending.
(gdb) run
Starting program: 
/pub/projects/intel_LPIA/svn/trunk/build_q1_sse/gnuradio-core/src/tests/.libs/test_filter
Failed to read a valid object file image from memory.
[Thread debugging using libthread_db enabled]
[New Thread -1214613824 (LWP 15638)]
Breakpoint 3 at 0xb7e42ce5: file 
../../../../../gnuradio-core/src/lib/general/gr_remez.cc, line 864.
Pending breakpoint "float_dotprod_sse" resolved
[Switching to Thread -1214613824 (LWP 15638)]

Breakpoint 1, main () at ../../../../gnuradio-core/src/tests/test_filter.cc:27
27      main (int argc, char **argv)


(gdb) break float_dotprod_sse
Note: breakpoint 3 also set at pc 0xb7e42ce5.
Breakpoint 4 at 0xb7e42ce5: file 
../../../../../gnuradio-core/src/lib/general/gr_remez.cc, line 864.

(gdb) list
859         punt ("gr_remez: insufficient extremals -- cannot continue");
860
861       if (err == -3)
862         punt ("gr_remez: too many extremals -- cannot continue");
863
864       return std::vector<double> (&coeff[0], &coeff[numtaps]);
865     }
866
867
868
(gdb) list float_dotprod_sse
859         punt ("gr_remez: insufficient extremals -- cannot continue");
860
861       if (err == -3)
862         punt ("gr_remez: too many extremals -- cannot continue");
863
864       return std::vector<double> (&coeff[0], &coeff[numtaps]);
865     }
866
867
868