solidity-cfg-builder

A control-flow graph builder for Solidity smart contracts.

Overview

This package generates a control-flow graph from Solidity contracts. Control-flow graphs are helpful as a graphic representation of the semantics of programs, and are the basis of many static analysis approaches to optimizing and verifying programs. This package is the basis of a static analysis approach I am currently developing.

solidity-cfg-builder is developed in Haskell, utilising a Solidity syntax parser used in the runtime verification tool for Solidity contractLarva. The version of the parser used in the project is packaged in the project.

This tool given Solidity code generates a control-flow graph in DOT notation, which can be visualised using GraphViz.

Building the tool

Requirements: cabal v2.4.* (e.g. install the full Haskell Platform)

Compilation: Follow the instructions here

Tool usage:

For correct results always make sure that the Solidity code compiles with a Solidity compiler.

To use the tool pass the location of a solidity file and the preferred location of the output to the executable, e.g. execute:

"./solidity-cfg-builder" <solidity-code.sol> <cfg.gv>

License

This project is licensed under the terms of the Apache 2.0 license.

TODO (See Issues for an up-to-date list)

1. Handle function modifiers
2. Allow option to flatten CFGs with function calls (consider also contract inheritance)
3. Handle block of statements at end of function definition
4. Event triggering is being parsed as a function call. Post-process to show triggerring of event explicitly.

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FAQ and Common Problems

When compiling the code I get the error: Could not find module ‘Text.Parsec’.

Make sure you have installed parsec. Also, see this stackoverflow thread (https://stackoverflow.com/questions/9058914/cant-find-parsec-modules-in-ghci)

cabal install parsec