gecko/build/autoconf/check_debug_ranges.py
2012-05-21 12:12:37 +01:00

61 lines
2.1 KiB
Python

# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
# This script returns the number of items for the DW_AT_ranges corresponding
# to a given compilation unit. This is used as a helper to find a bug in some
# versions of GNU ld.
import subprocess
import sys
import re
def get_range_for(compilation_unit, debug_info):
'''Returns the range offset for a given compilation unit
in a given debug_info.'''
name = ranges = ''
search_cu = False
for nfo in debug_info.splitlines():
if 'DW_TAG_compile_unit' in nfo:
search_cu = True
elif 'DW_TAG_' in nfo or not nfo.strip():
if name == compilation_unit:
return int(ranges, 16)
name = ranges = ''
search_cu = False
if search_cu:
if 'DW_AT_name' in nfo:
name = nfo.rsplit(None, 1)[1]
elif 'DW_AT_ranges' in nfo:
ranges = nfo.rsplit(None, 1)[1]
return None
def get_range_length(range, debug_ranges):
'''Returns the number of items in the range starting at the
given offset.'''
length = 0
for line in debug_ranges.splitlines():
m = re.match('\s*([0-9a-fA-F]+)\s+([0-9a-fA-F]+)\s+([0-9a-fA-F]+)', line)
if m and int(m.group(1), 16) == range:
length += 1
return length
def main(bin, compilation_unit):
p = subprocess.Popen(['objdump', '-W', bin], stdout = subprocess.PIPE, stderr = subprocess.PIPE)
(out, err) = p.communicate()
sections = re.split('\n(Contents of the|The section) ', out)
debug_info = [s for s in sections if s.startswith('.debug_info')]
debug_ranges = [s for s in sections if s.startswith('.debug_ranges')]
if not debug_ranges or not debug_info:
return 0
range = get_range_for(compilation_unit, debug_info[0])
if range is not None:
return get_range_length(range, debug_ranges[0])
return -1
if __name__ == '__main__':
print main(*sys.argv[1:])