A Modern Compiler for the French Tax Code

11/16/2020
by   Denis Merigoux, et al.
0

In France, income tax is computed from taxpayers' individual returns, using an algorithm that is authored, designed and maintained by the French Public Finances Directorate (DGFiP). This algorithm relies on a legacy custom language and compiler originally designed in 1990, which unlike French wine, did not age well with time. Owing to the shortcomings of the input language and the technical limitations of the compiler, the algorithm is proving harder and harder to maintain, relying on ad-hoc behaviors and workarounds to implement the most recent changes in tax law. Competence loss and aging code also mean that the system does not benefit from any modern compiler techniques that would increase confidence in the implementation. We overhaul this infrastructure and present Mlang, an open-source compiler toolchain whose goal is to replace the existing infrastructure. Mlang is based on a reverse-engineered formalization of the DGFiP's system, and has been thoroughly validated against the private DGFiP test suite. As such, Mlang has a formal semantics; eliminates previous handwritten workarounds in C; compiles to modern languages (Python); and enables a variety of instrumentations, providing deep insights about the essence of French income tax computation. The DGFiP is now officially transitioning to Mlang for their production system.

READ FULL TEXT

page 1

page 2

page 3

page 4

research
11/08/2017

DLVM: A modern compiler infrastructure for deep learning systems

Deep learning software demands reliability and performance. However, man...
research
07/21/2017

A Verified Compiler for Probability Density Functions

Bhat et al. developed an inductive compiler that computes density functi...
research
10/18/2018

Don't Unroll Adjoint: Differentiating SSA-Form Programs

This paper presents reverse-mode algorithmic differentiation (AD) based ...
research
02/09/2021

NOELLE Offers Empowering LLVM Extensions

Modern and emerging architectures demand increasingly complex compiler a...
research
09/17/2022

langcc: A Next-Generation Compiler Compiler

Traditionally, parsing has been a laborious and error-prone component of...
research
04/06/2023

Spade: An Expression-Based HDL With Pipelines

Spade is a new open source hardware description language (HDL) designed ...
research
02/08/2022

K-ST: A Formal Executable Semantics of PLC Structured Text Language

Programmable Logic Controllers (PLCs) are responsible for automating pro...

Please sign up or login with your details

Forgot password? Click here to reset