Which files to set the breakpoints in?

[vimarsh6739]

Hi, I'm trying to use depyf on the following example(it is a simplified form of the README with only the eager backend).

import torch
from torch import _dynamo as torchdynamo
from typing import List

@torch.compile(backend="eager")
def toy_example(a, b):
    x = a / (torch.abs(a) + 1)
    if b.sum() < 0:
        b = b * -1
    return x * b

def main():
    for _ in range(100):
        toy_example(torch.randn(10), torch.randn(10))

if __name__ == "__main__":
    import depyf
    with depyf.prepare_debug("./dump_src_dir"):
        main()
    with depyf.debug():
        main()

It produces the following output in ./dump_src_dir

➜  dump_src_dir ls
'__compiled_fn_0 Captured Graph 0.py'   full_code_for_toy_example_0.py                                        __transformed_code_1_for_torch_dynamo_resume_in_toy_example_at_8.py
'__compiled_fn_3 Captured Graph 0.py'   __transformed_code_0_for_torch_dynamo_resume_in_toy_example_at_8.py
'__compiled_fn_4 Captured Graph 0.py'   __transformed_code_0_for_toy_example.py

Which files am I supposed to set the breakpoints in? The code just falls through no matter where I set the breakpoint.

[youkaichao]

Hi, you can set break points in __compiled_fn and __transformed_code. Here is my screenshot with vscode:

Can you give more information about how you are debugging?

[youkaichao]

And here is another screenshot to hit breakpoint in __compiled_fn:

[vimarsh6739]

Oh I see. Is it necessary to use VSCode/VS here? I'm manually setting the breakpoint after opening the file in vim (using breakpoint()).

[youkaichao]

Do you use pdb in vim? Sorry but I don't know how to use vim for debugging :( Not sure what would be wrong with vim.

[vimarsh6739]

Yes, I'm using pdb. breakpoint() implicitly calls pdb.set_trace() (according to the docs here).

[youkaichao]

By "manually setting breakpoint", do you mean you modify the code to add breakpoint()? That would not work though. You need to set breakpoint using debuggers. You can use pdb b file:line.

[youkaichao]

These *.py files are not executed directly by Python. And the modification you made to them will not take any effect.

[vimarsh6739]

Oh ok, so if I want to use pdb, should I set a breakpoint() before calling main() in the depyf.debug() context window?

[vimarsh6739]

This seems to work. I'm closing this. Thank you for the quick response!

I essentially set a breakpoint() in the original code like this.

with depyf.debug():
    breakpoint()
    main()

[youkaichao]

Wow that's a good solution 👍

[youkaichao]

@vimarsh6739 I added a breakpoint inside depyf.debug, so you don't have to add one any more! In addition, the program does not ask for input, so pdb users should be happy now. Try it out!

[vimarsh6739]

I just pulled in the updates, and this seems to work! Thanks for this.