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#-------------------------------------------------------------------------------
# elftools example: dwarf_die_tree.py
#
# In the .debug_info section, Dwarf Information Entries (DIEs) form a tree.
# pyelftools provides easy access to this tree, as demonstrated here.
#
# Eli Bendersky (eliben@gmail.com)
# This code is in the public domain
#-------------------------------------------------------------------------------
from __future__ import print_function
import sys
# If elftools is not installed, maybe we're running from the root or examples
# dir of the source distribution
try:
import elftools
except ImportError:
sys.path.extend(['.', '..'])
from elftools.common.py3compat import bytes2str
from elftools.elf.elffile import ELFFile
def process_file(filename):
print('Processing file:', filename)
with open(filename, 'rb') as f:
elffile = ELFFile(f)
if not elffile.has_dwarf_info():
print(' file has no DWARF info')
return
# get_dwarf_info returns a DWARFInfo context object, which is the
# starting point for all DWARF-based processing in pyelftools.
dwarfinfo = elffile.get_dwarf_info()
for CU in dwarfinfo.iter_CUs():
# DWARFInfo allows to iterate over the compile units contained in
# the .debug_info section. CU is a CompileUnit object, with some
# computed attributes (such as its offset in the section) and
# a header which conforms to the DWARF standard. The access to
# header elements is, as usual, via item-lookup.
print(' Found a compile unit at offset %s, length %s' % (
CU.cu_offset, CU['unit_length']))
# Start with the top DIE, the root for this CU's DIE tree
top_DIE = CU.get_top_DIE()
print(' Top DIE with tag=%s' % top_DIE.tag)
# Each DIE holds an OrderedDict of attributes, mapping names to
# values. Values are represented by AttributeValue objects in
# elftools/dwarf/die.py
# We're interested in the DW_AT_name attribute. Note that its value
# is usually a string taken from the .debug_string section. This
# is done transparently by the library, and such a value will be
# simply given as a string.
name_attr = top_DIE.attributes['DW_AT_name']
print(' name=%s' % bytes2str(name_attr.value))
# Display DIEs recursively starting with top_DIE
die_info_rec(top_DIE)
def die_info_rec(die, indent_level=' '):
""" A recursive function for showing information about a DIE and its
children.
"""
print(indent_level + 'DIE tag=%s' % die.tag)
child_indent = indent_level + ' '
for child in die.iter_children():
die_info_rec(child, child_indent)
if __name__ == '__main__':
for filename in sys.argv[1:]:
process_file(filename)
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