During May 2025, contributed to the rust-lang/gcc repository by implementing OpenMP 5.0 declare mapper support for C and C++. This work enabled developers to define custom data mappers for aggregate types, allowing more flexible and correct data movement in OpenMP target regions. The feature required end-to-end integration across parsing, semantic analysis, and code generation in both the compiler frontends and the libgomp runtime. Leveraging expertise in C++ language features, compiler development, and parallel computing, the contribution aligned gcc with the OpenMP 5.0 specification and reduced manual data-movement coding, improving both correctness and performance potential for offload scenarios.