riscv64_table_relocs.py

#!/usr/bin/env python3
import sys
from elftools.elf.elffile import ELFFile

R_RISCV_ADD32 = 35
R_RISCV_SUB32 = 39

def main():
    if len(sys.argv) != 2:
        sys.exit(1)
    filename = sys.argv[1]
    with open(filename, 'rb') as f:
        elf_file = ELFFile(f)
        relocs_map = {}
        for sec in elf_file.iter_sections():
            if not hasattr(sec, 'iter_relocations'):
                continue
            symbol_table = None
            if sec['sh_link']:
                symbol_table = elf_file.get_section(sec['sh_link'])
            for rel in sec.iter_relocations():
                r_type = rel['r_info_type']
                if r_type not in (R_RISCV_ADD32, R_RISCV_SUB32):
                    continue
                addr = rel['r_offset']
                sym_val = 0
                if symbol_table:
                    sym = symbol_table.get_symbol(rel['r_info_sym'])
                    sym_val = sym['st_value']
                addend = rel['r_addend'] if 'r_addend' in rel.entry else 0
                relocs_map.setdefault(addr, []).append((r_type, sym_val, addend))
        for addr in sorted(relocs_map.keys()):
            group = relocs_map[addr]
            has_add = any(r_type == R_RISCV_ADD32 for r_type, _, _ in group)
            has_sub = any(r_type == R_RISCV_SUB32 for r_type, _, _ in group)
            if not (has_add and has_sub):
                continue
            add_sub_offset = sum(sym_val + addend for r_type, sym_val, addend in group if r_type == R_RISCV_ADD32)
            add_sub_offset -= sum(sym_val + addend for r_type, sym_val, addend in group if r_type == R_RISCV_SUB32)
            if add_sub_offset == 0:
                continue
            address_str = f"0x{addr:08x}"
            print(f"{address_str:<16s} {add_sub_offset:<16d}")

if __name__ == '__main__':
    main()