Worked on the JuliaGPU/pocl repository to deliver forward-compatibility with LLVM 20, focusing on build system and compiler development using C++ and CMake. Addressed compatibility by renaming macros to resolve naming conflicts and updating build configuration scripts to detect and support LLVM 20, ensuring reliable builds across components. Adapted the diagnostics API to align with upstream changes, passing the correct filesystem context to prevent crashes during diagnostics. Fixed a critical bug by initializing a real filesystem, reducing maintenance risk and improving developer experience. The work enhanced system programming robustness, enabling smoother upgrades and more stable development workflows for downstream users.