[libunwind] gdb/idb debugger compatiblity

[Jesper Antonsson (LM/EAB)]

We're creating a prototype JIT compiler on Itanium and would like idb and gdb 
to handle the dynamically generated code, i.e. generate nice backtraces and 
allow debugging and stack traversal despite dynamic code in the "middle" of the 
call stack. At first I thought libunwind could help with this, but now I'm 
unsure. Are the debuggers currently able to interface with the libunwind 
dynamic descriptor tables somehow? If so, do I have to do anything in 
particular to make this work? I tested with test-dyn1 in the libunwind test 
suite, but even though it successfully prints its own stack trace, idb and gdb 
seem to fail. (I've compiled with ecc, btw, and had to modify the test case 
somewhat to make it run. The procedure, "template", was larger than the size 
argument handed to memcopy.)

If it isn't possible with libunwind, I would be very grateful for any pointers 
on how to otherwise accomplish gdb/idb dynamic code handling. Can I somehow use 
the Linux kernel unwind interface to register procedure descriptors from my 
user code?

Best regards,
Jesper Antonsson