This makes -D/--define more useful in stack.py/perf.py/perfbd.py by no
longer hiding undfined children entries.
For example:
$ ./scripts/stack.py lfs.ci lfs_util.ci -Dfunction=lfsr_mount -t
function frame limit
lfsr_mount 96 2816
|-> lfsr_fs_gc 80 2720
|-> lfsr_mtree_gc 176 2640
|-> lfsr_mdir_commit 576 2464
... snip ...
Now shows all functions in the hot path of lfsr_mount, where before it
would only show functions in the hot path of lfsr_mount that were also
_named_ lfsr_mount.
The previous behavior was technically not wrong... but not very useful
(and confusing).
---
This was actually quite a bit annoying to get working because of the
possibility of function call cycles.
I ended up turning stack.py's result type into a fully connected graph,
which only works because Python has a cycle detector. (Actually this
script is so short-lived we probably wouldn't care if this leaked
memory.)
A nice side effect of this is now all the recursive scripts (stack.py,
perf.py, and perfbd.py) share the same internal result representation
and recursive printing logic, which is probably a good thing.
Christopher Haster
0c3868f92c