Copy-and-Patch Just-in-Time Compiler for R

Copy-and-patch is a technique for building baseline just-in-time compilers from existing interpreters. It has been successfully applied to languages such as Lua and Python. This paper reports on our experience using this technique to implement a compiler for the R programming language. We describe how this new compiler integrates with the GNU R virtual machine, present the key optimizations we implemented, and evaluate the feasibility of this approach for R. Copy-and-patch also allows extensions such as integration of the feedback recording required by multi-tier compilation. Our evaluation on 57 programs demonstrates very fast compilation times (980 bytecode instructions per millisecond), reasonable performance gains (1.15x–1.91x speedup over GNU R), and manageable implementation complexity.