Associating source to a running program

[Olivier Parisy]

Hi,

I'm trying to step through a gcj-compiled java program.

I get outputs such as this one:
(gdb) step
JvRunMain (klass=0xf3c310, argc=1, argv=0x33ec8)
     at /home/olivier/gcj/w32gcc/src/gcc/libjava/prims.cc:1552
1552    /home/olivier/gcj/w32gcc/src/gcc/libjava/prims.cc: No such file 
or directory.
         in /home/olivier/gcj/w32gcc/src/gcc/libjava/prims.cc
Current language:  auto; currently c++

This makes sense, as prims.cc is probably part of libjava runtime, and 
was only available at gcc/gcj compilation, but not during program execution.

Considering that this source code is available elsewhere on the file 
system, how can I specify to GDB where it can find it?

Best regards,
Olivier Parisy.