Hyperledger - Implement an SSA intermediate representation for the Solang compiler

About the Organization

Solang is an open-source Solidity compiler written in Rust. It generates an intermediate representation in a Control Flow Graph (CFG) for each function in a Solidity contract during compilation. The CFG contains high level expressions and instructions, which help in some aspects of code analysis and optimization, but are not suitable for more advanced optimization passes, such as liveness analysis and partial redundancy elimination. In this project, mentees will have hands-on experience implementing a modern Single Static Assignment intermediate representation for the Solang compiler. This addition will bring many advantages for the compiler, such as the possibility to break down complex constructs into lower level instructions and the facilitation of code analysis. We propose for the mentorship the introduction of a new intermediate representation to live between the existing one (the CFG representation - read more about it at the Additional Information section below) and the LLVM-IR. It should feature three-address code in a Single Static Assignment (SSA) minimal form. The construction of such a form happens in two steps: Phi function insertion Variable renaming The objective is to decouple the types and expressions we have used for the AST from the existing CFG intermediate representation. In addition, the new low level intermediate code must contain assertions that ensure the instructions are created with valid operands and expressions.