Calling the same unconstrained fn multiple times in the program multiplies debug metadata

[sirasistant]

Aim

Have a program that uses brillig hints in a loop

Expected Behavior

Artifact size and compile time should not explode.

Bug

In this project ram usage goes to 100gigs, postprocessing after ACIR generation can take 10 minutes and the compressed debug metadata in the artifact weights 1 gigabyte.

The problem is that we always associate debug metadata with acir callsites. We've succesfully deduplicated the brillig code by the separation unconstrained fn / brillig call in the Program struct, but brillig-related debug metadata still gets added over and over again on every callsite, just changing the ACIR index.

To Reproduce

Minimal repro:

global ITERATION_COUNT = 100000;

unconstrained fn some_unconstrained_fn(x: Field, y: Field) -> Field {
    let x_u128 = U128::from_integer(x);
    let y_u128 = U128::from_integer(y);
    (x_u128 / y_u128).to_integer()
}

fn main(data: [Field; ITERATION_COUNT]) -> pub Field {
    let mut acc = data[0];

    for i in 1..ITERATION_COUNT {
        acc = some_unconstrained_fn(acc, data[i]);
    }

    acc
}

some_unconstrained_fn has 1558 locations. It gets called 100k times, and the final Program struct debug metadata locations has 155M entries.

Project Impact

None

Impact Context

No response

Workaround

None

Workaround Description

No response

Additional Context

No response

Installation Method

None

Nargo Version

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NoirJS Version

No response

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Support Needs

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