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# 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 re
import subprocess
import sys
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 and ranges != "":
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,
universal_newlines=True,
)
(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:]))
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