A Method for Implementing Function Reordering in GNU ld

This paper aims to implement function reordering in the GNU ld linker to improve program execution efficiency. The approach begins by adding the -ffunction-sections parameter during the GCC compilation phase, which places each function in its own section, laying the groundwork for subsequent layout adjustments. During the linking phase, the input files are traversed to parse the section nodes related to functions, particularly the statement_list nodes containing the various functions. Finally, by sorting and adjusting the statement_list nodes, the layout of functions in the executable file is made more aligned with actual call relationships, thereby reducing cache misses and the overhead caused by swapping in and out. Experimental results show that the function reordering feature in the linking phase increases program IPC by 1.116%, improves L1 cache hit rate by 1.625%, and reduces overall execution time by 2.888%. This method significantly enhances program performance by optimizing function layout, demonstrating the feasibility and effectiveness of implementing function reordering in GNU ld.