Other debuggers can be instructed to decorate the stacktrace with the
value of SP. Our SP equivalent is the frame offset, since we can add it
to the Stackframe structure without incurring into added costs we
should, so that frontends can use it if they want.
- always print a header with the path to the file being displayed
- always evaluate the linespec argument, even if a scope prefix is present
Fixes#711, #713
The test in question tries to 'next' over a call to wg.Done, this is
not guaranteed to succeed, if the goroutine gets suspended after
wg.Done has notified the waiting group but before returning to
main.dostuff the program could quit before the goroutine is resumed.
On Windows we can sometimes encounter threads stopped in locations for
which we do not have entries in debug_frame.
These cases seem to be due to calls to Windows API in the go runtime,
we can still produce a (partial) stack trace in this circumstance by
following frame pointers (starting with BP).
We still prefer debug_frame entries when available since go functions
do not have frame pointers before go1.8.
