Comparative Analysis of Linking Efficiency

Abstract

This study examines the differences between two modern linkers, LLD and mold, focusing on their efficiency during software development. Although the linking process, which combines multiple object files into a single executable, typically occupies a minor fraction of the total compilation time, optimizing it can significantly enhance the overall build efficiency - particularly during the development of large-scale projects. The research aims to determine codebase-level differences between these linkers and assess their performance across various metrics, including linking time, memory usage, and the time spent on different phases of the linking process, using CMake and Bitcoin Core as benchmarks. Furthermore, the study extends to examining the executables produced by both linkers from the HDiffPatch project, comparing their execution times and sizes. The findings consistently show that mold outperforms LLD in terms of speed and efficiency, which results from its comprehensive utilization of parallel processing techniques. Nonetheless, LLD offers broader applicability by supporting a wider range of file formats and being suitable for both embedded and kernel programming. Therefore, the selection of a linker ultimately depends on the specific requirements of the project and the characteristics of the target machine.