On Fri, Mar 11 2016, Marcin KoÅcielnicki wrote:
We can always error() in there (and KFAIL the testcase in gdb.trace
that exercises it). However, returning garbage here doesn't result in
garbage backtrace - this only collects data, if the unwinder actually
doing the work later determines it should look for the return address
on the stack, it'll just ignore our collected $r14 and consider the
return address unavailable (unless another collect rule happened to
match it).
Well, from that test case it appears that `$_ret' is generally not
expected to work very reliably. Since r14 usually does work near
function entry, this may be sufficient for now.
So I'm OK with the patch. Please add a small comment stating that this
is a best-can-do approach that usually works near function entry and may
yield wrong results otherwise.