crytic / roundme

roundme

roundme is a human-assisted rounding analyzer. It helps its operator determine whether an arithmetic operation should round up or down.

Features

• Recommends whether an arithmetic operation needs to round up or down
• Generates LaTeX-based reports in PDF

Rules

rounding() is the expected rounding direction for the result (up or down)

• A + B => rounding(A), rounding(B) (addition does not change the rounding direction)
• A - B => rounding(A), ! rounding(B) (the rounding direction of the substracted element is inverse of the expected rounding)
• A * B => rounding(A), rounding(B), rounding(*) (multiplication does not change the rounding direction)
• A / B => rounding(A), ! rounding(B), rounding(/) (the rounding direction of the denominator is the inverse of the expected rounding)
• A ** B
  • If A>=1 => rounding(A), rounding(B)
  • If A<1 => rounding(A), ! rounding(B) (if A is below 1, the rounding direction of the exponent is the inverse of the expected rounding)

How to use

• Run roundme init-sample to generate a default configuration file.
• Run roundme init to generate user configuration file.
• Run roundme analyze to analyze the configuration file
• Run roundme analyze --output-format pdf to generate a PDF (require latexmk)

Running roundme analyze --output-format pdf on the default configuration will generate the following:

Configuration

roundme relies on a configuration file:

formula: a * b / c 
round_up: true
less_than_one: ["a * b"] # optional
greater_than_one: ["c"] # optional

• formula contains the formula to be analyze
• round_up determines if the result of the formula should round up or down
• less_than_one is used for the ** rules (raw string comparison and sensible to space)
• greater_than_one is used for the ** rules (raw string comparison and sensible to space)

See the balancer V2 example.

Install

Install with

cargo install roundme

To install the latest GitHub version

git clone [email protected]:crytic/roundme.git
cd roundme
cargo install --path .

roundme's Issues

Feature request: support negative values

-1 * x will throw the following error

thread 'main' panicked at src/main.rs:61:60:
called `Result::unwrap()` on an `Err` value: UnrecognizedToken { token: (1, Token(7, "-"), 2), expected: ["\"(\"", "r#\"[0-9]+\"#", "r#\"[a-zA-Z]+\"#"] }
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Feature request: generate config file from static code analysis output

Hello
Great tool, thanks for building this!

I wish the config file was automatically generated from the source code.

This could be integrated into Slither, for example, which could extract all mathematical expressions, and the user would point out whether the different parameters (with names and links pointing to references in the code) were supposed to round up or down.

Question: rounding direction for multiplication

So on the generated reports, rounding directions are included for both multiplication and division operations. Why is a rounding direction included for multiplication, since there is no precision loss resulting from multiplication operations?

Thanks for making this tool!

Feature: generate template code

Idea from @tjade273: we can generate template solidity code based on the formula. We can also auto generate a well formed documentation alongside

This will be useful in particular during the early stage development cycle.

We might need to templatize the generation to use the most common lib (ex: prb-math / solmate)