Worked on the llvm/clangir repository to enhance GCov coverage reporting for multi-file basic blocks. Developed new data structures and logic in C++ and Shell to accurately track line origins within blocks, ensuring that coverage statistics correctly attribute lines to their respective source files. Focused on aligning LLVM’s GCov behavior with GCC by addressing previous issues of over-filtering and under-counting. Applied skills in code coverage tools, compiler development, debugging, and testing to deliver this feature as a single, cohesive commit. The work improved the accuracy and reliability of coverage data, supporting more precise testing and analysis for complex codebases.