Tried Python 3.6's systemtap probes and gave up on them.

- Built a version of Python 3.6 with systemtap descriptors
- systemtap scripts don't compile under Ubuntu Xenial.
- Although a StackOverflow answer suggested that building systemtap from
  source works, it didn't work for me.

It appears to be very brittle.  systemtap 3.2 doesn't compile, but 3.1
does.  But even under 3.1, the .stp scripts themselves don't compile!

benchmarks/systemtap.sh

@@ -0,0 +1,75 @@
#!/bin/bash
#
# Following:
# https://docs.python.org/3/howto/instrumentation.html
#
# Couldn't get this to work.  Even building it from source doesn't work!
# 'stap' invokes a compiler, and I get compiler errors.
#
# It appears to be very brittle.
#
# https://stackoverflow.com/questions/46047270/systemtap-error-on-ubuntu
#
# Usage:
#   ./systemtap.sh <function name>

set -o nounset
set -o pipefail
set -o errexit

deps() {
  # 'stap' lives in systemtap package
  sudo apt install systemtap systemtap-sdt-dev
}

stap-deps() {
  # For DWARF debugging info, interesting.
  sudo apt install libdw-dev libdw1
}

# NOTE: systemtap-3.2 is out, but doesn't compile on Ubuntu xenial!
download() {
  wget --no-clobber --directory _tmp \
    https://sourceware.org/systemtap/ftp/releases/systemtap-3.1.tar.gz
}

extract() {
  cd _tmp
  tar -x -z < systemtap-3.1.tar.gz
}

readonly PY36=~/src/languages/Python-3.6.1

build-python() {
  pushd $PY36
  # There is no --with-systemtap/
  ./configure --with-dtrace
  make -j 7
  popd
}

# Default Python build doesn't have it
elf() {
  readelf -n $(which python3)
  echo ---
  # Now this has "stapsdt" -- SystemTap probe descriptors.
  readelf -n $PY36/python
}

_demo() {
  #local stp="$PWD/benchmarks/call-hierarchy.stp"

  # C compile errors?  It's getting further.
  #local stp="$PY36/Lib/test/dtracedata/call_stack.stp"
  local stp="$PY36/Lib/test/dtracedata/gc.stp"
  #local stp="$PY36/Lib/test/dtracedata/assert_usable.stp"

  local py="$PWD/test/sh_spec.py"

  pushd $PY36
  stap -v $stp -c "./python $py"
  popd
}
demo() { sudo $0 _demo; }

"$@"