For Michal

run-examples.md

Examples of running run-program-with-counts.py

$ python run-python-program-with-counts.py ../test/example/fib.py
fib(2)= 2, fib(3) = 3, fib(4) = 5

Event "call" seen 25 times.
Event "line" seen 70 times.
Event "opcode" seen 358 times.
Event "return" seen 24 times.
$ python run-python-program-with-counts.py ../test/example/gcd.py 3 5
The GCD of 3 and 5 is 1
Event "call" seen 12 times.
Event "line" seen 65 times.
Event "opcode" seen 314 times.
Event "return" seen 11 times.
$

The programs fib.py and gcd.py` can be found in https://github.com/Trepan-Debuggers/python3-trepan/tree/master/test/example

run-python-program-with-count.py

#!/usr/bin/env python3
"""
A simple program to run a Python program and dump statistics of how many
sys_trace events ("call", "return", "line", "opcode") it runs.

Run like this:

  python3 run-python-program-with-count.py *your-python-program* *args*

"""
import atexit
import os.path as osp
import sys
import types
from collections import defaultdict
from typing import Callable, Optional

_globals = globals().copy()

class TraceEvents:
    """
    A simple sys.settrace event handler for counting sys_trace() events.
    """
    def __init__(self):
        self.event_counts = defaultdict(int)

    def event_handler(self, call_frame: types.FrameType, event: str, _) -> Optional[Callable]:
        self.event_counts[event] += 1

        # If you don't want to count opcode you can comment this out.
        # Actually, it probably only needs to be set once (per frame
        # call?, per trace session?)

        call_frame.f_trace_opcodes = True

        # print(f"event: {event} {call_frame.f_code.co_filename}:{call_frame.f_lineno}")

        # We need to return our method to make sure tracing keeps calling us.
        return self.event_handler

    def stop_trace_and_dump(self):
        sys.settrace(None)
        for event, count in self.event_counts.items():
            print(f'Event "{event}" seen {count} times.')


def run_and_trace_program(python_path: str):
     """
     Compile `python_path` and evaluate it in a way to keep track
     of the instruction events it runs.
     """

     if not osp.exists(python_path):
         print(f"Python file {python_path} does not exist")

     compiled = compile(open(python_path, "r").read(), filename=python_path, mode='exec')
     tracer = TraceEvents()
     atexit.register(tracer.stop_trace_and_dump)
     sys.argv.pop(0)
     sys.settrace(tracer.event_handler)
     exec(compiled, _globals)

if __name__ == "__main__":
    traced_program = sys.argv[1]
    run_and_trace_program(traced_program)