The elfutils DWARF unwinder has a couple of limitations:
1. libdwfl doesn't have an interface for getting register values, so we
have to bundle a patched version of elfutils with drgn.
2. Error handling is very awkward: dwfl_getthread_frames() can return an
error even on success, so we have to squirrel away our own errors in
the callback.
Furthermore, there are a couple of things that will be easier with our
own unwinder:
1. Integrating unwinding using ORC will be easier when we're handling
unwinding ourselves.
2. Support for local variables isn't too far away now that we have DWARF
expression evaluation.
Now that we have the register state, CFI, and DWARF expression pieces in
place, stitch them together with the new unwinder, and tweak the public
API a bit to reflect it.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
In preparation for adding a "real", internal-only struct
drgn_stack_frame, replace the existing struct drgn_stack_frame with
explicit trace/frame arguments.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
