175 lines
5 KiB
Python
Executable file
175 lines
5 KiB
Python
Executable file
#!/usr/bin/env python3
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""" Compare the sizes of the .eh_frame section in the original binary and of
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the .text in the generated .eh_elf.so. """
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import argparse
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import os
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import subprocess
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from collections import namedtuple
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from shared_python import elf_so_deps
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''' An ELF object, including the path to the ELF itself, and the path to its
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matching eh_elf '''
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ElfObject = namedtuple('ElfObject', 'elf eh_elf')
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def format_size(size):
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''' Format a size to a human-readable string '''
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units = ['B', 'KiB', 'MiB', 'GiB'] # We'll never go over that
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cur_unit = 0
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while cur_unit < len(units) and size >= 1024:
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size /= 1024
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cur_unit += 1
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return '{:.1f} {}'.format(size, units[cur_unit])
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def section_size(elf_loc, section_name):
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''' Find the size of a given section in some elf file '''
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if not os.path.isfile(elf_loc):
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raise FileNotFoundError
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try:
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objdump_out = subprocess.check_output(['objdump', '-h', elf_loc]) \
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.decode('utf-8')
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except subprocess.CalledProcessError as exn:
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raise Exception(("Cannot obtain section {} size for {}: objdump "
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"terminated with exit code {}.").format(
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section_name, elf_loc, exn.returncode))
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for line in objdump_out.split('\n'):
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line = line.strip()
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if not line or not '0' <= line[0] <= '9': # not a section line
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continue
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spl = line.split()
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if spl[1] != section_name:
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continue
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return int(spl[2], 0x10)
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raise Exception("No such section {} in {}".format(section_name, elf_loc))
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def matching_eh_elf(eh_locs, elf_name):
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''' Get the .eh_elf.so file matching elf_name in the list of directories
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eh_locs.
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Raises FileNotFoundError if there is no such file '''
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basename = os.path.basename(elf_name) + '.eh_elf.so'
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for prefix in eh_locs:
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eh_elf_path = os.path.join(prefix, basename)
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if os.path.isfile(eh_elf_path):
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return eh_elf_path
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raise FileNotFoundError("No such file {}".format(basename))
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def objects_list(args):
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''' Get the list of elf objects to process '''
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out = []
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if args.deps:
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objects = set(args.object)
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for obj in args.object:
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objects = objects.union(elf_so_deps(obj))
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objects = list(objects)
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objects.sort()
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else:
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objects = args.object
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for obj in objects:
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out.append(ElfObject(obj, matching_eh_elf(args.eh_elfs, obj)))
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return out
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def process_args():
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''' Process `sys.argv` arguments '''
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parser = argparse.ArgumentParser(
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description=("Compare the sizes of the .eh_frame section in the "
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"original binary and of the .text in the generated "
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".eh_elf.so."),
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)
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parser.add_argument('--deps', action='store_true',
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help=("Also compare the shared objects this object "
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"depends on"))
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parser.add_argument('--eh-elfs', required=True, action='append',
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help=("Indicate the directory in which eh_elfs are "
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"located"))
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parser.add_argument('object', nargs='+',
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help="The ELF object(s) to process")
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return parser.parse_args()
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def main():
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args = process_args()
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objs = objects_list(args)
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section_size(objs[0].elf, '.eh_frame')
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col_names = [
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'Shared object',
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'Orig eh_frame',
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'Gen eh_elf',
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'Growth',
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]
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col_len = []
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displayed_name_filter = lambda x: os.path.basename(x.elf)
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max_elf_name = max(map(lambda x: len(displayed_name_filter(x)), objs))
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col_len.append(max(max_elf_name, len(col_names[0])))
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for i in range(1, 4):
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col_len.append(len(col_names[i]) + 1)
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col_len = list(map(str, col_len))
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header_format = ('{:<' + col_len[0] + '} '
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'{:<' + col_len[1] + '} '
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'{:<' + col_len[2] + '} '
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'{:<' + col_len[3] + '}')
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row_format = ('{:>' + col_len[0] + '} '
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'{:>' + col_len[1] + '} '
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'{:>' + col_len[2] + '} '
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'{:>' + col_len[3] + '}')
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print(header_format.format(
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col_names[0],
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col_names[1],
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col_names[2],
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col_names[3],
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))
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total_eh_frame_size = 0
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total_eh_elf_size = 0
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for obj in objs:
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eh_frame_size = section_size(obj.elf, '.eh_frame')
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eh_elf_size = section_size(obj.eh_elf, '.text')
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total_eh_frame_size += eh_frame_size
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total_eh_elf_size += eh_elf_size
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print(row_format.format(
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displayed_name_filter(obj),
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format_size(eh_frame_size),
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format_size(eh_elf_size),
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'{:.2f}'.format(eh_elf_size / eh_frame_size)))
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print(row_format.format(
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'Total',
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format_size(total_eh_frame_size),
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format_size(total_eh_elf_size),
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'{:.2f}'.format(total_eh_elf_size / total_eh_frame_size)))
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if __name__ == '__main__':
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main()
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