IDOL: Improved Different Optimization Levels Testing for Solidity Compilers

TL;DR

This paper introduces IDOL, a novel testing method for Solidity compilers that uses reverse optimization transformations to uncover compiler bugs, enhancing smart contract security.

Contribution

IDOL is the first approach to apply reverse optimization transformations for testing Solidity compilers, revealing previously unknown optimization bugs.

Findings

Discovered 3 compiler optimization bugs using IDOL

Demonstrated effectiveness of reverse transformations in bug detection

Improved testing coverage for Solidity compiler optimization logic

Abstract

As blockchain technology continues to evolve and mature, smart contracts have become a key driving force behind the digitization and automation of transactions. Smart contracts greatly simplify and refine the traditional business transaction processes, and thus have had a profound impact on various industries such as finance and supply chain management. However, because smart contracts cannot be modified once deployed, any vulnerabilities or design flaws within the contract cannot be easily fixed, potentially leading to significant financial losses or even legal issues. The compiler, as a critical component in the development process, directly affects the quality and security of smart contracts. This paper innovatively proposes a method, known as the Improved Different Optimization Levels (IDOL), for testing the Solidity compiler. The key idea behind IDOL is to perform reverse optimization transformations (i.e., change optimized form into unoptimized form) to generate semantically equivalent variants of the smart contracts under test, aiming to maximize the opportunities to trigger the optimization logic of compilers. We conducted a preliminary evaluation of IDOL and three confirmed compiler optimization bugs have been uncovered at the time of writing.