μSPL - Proprietary Graphics Language Transpiler : Asserting translation correctness using runtime verification

Abstract: The Swedish Armed Forces are currently considering extending the operational life of the Saab JAS 39 Gripen C/D multirole fighter aircraft by an additional 10 to 20 years. This has resulted in a need to upgrade many of the hardware components originally developed in the late 1980s and early 1990s. These upgrades include the Application Specific Integrated Circuits (ASICs) used to generate graphics in the aircraft’s Cockpit Display System (CDS), made programmable through the Symbol Programming Language (SPL). SPL is a proprietary Domain Specific Language (DSL) developed specifically to be used with the custom hardware in the Gripen’s CDS. An upgrade of the underlying hardware would necessitate migrating the old SPL software to some other format suitable for modern hardware. Large parts of this process could be automated with the help of a source-to-source compiler, i.e., a transpiler. In this thesis, we present a translation-verifying transpiler for a subset of SPL, dubbed μSPL, that outputs equivalent OpenGL/C++ programs. Verification is done at runtime against a reference program execution trace produced by the transpiler by means of symbolic execution in the operational semantics of μSPL. An observational study was made to evaluate the solution and the soundness of the μSPL semantics. From the results of the observational evaluation, we find that the chosen method for translation verification is contextually suitable, albeit with potential for improvement in the details of the implementation.