libdwfl: Only skip reset of return register for non-CIE-return regno (ppc64).

For PPC64 we skip resetting the return register if it is already set.
This is because on PPC64 there are two DWARF registers numbers that can
represent the same register. Setting the return address again confuses
the unwinder. But we do want to reset it if the register number
(non-translated by the ppc64 ebl) is equal to the actual register number
as set in the CIE as return address. This happens on older toolchains in
.debug_frame where the return address is set to 108, but the ebl abi_cfi
also sets register number 65.

Signed-off-by: Mark Wielaard <mjw@redhat.com>
2 files changed