1 #-------------------------------------------------------------------------------
2 # elftools example: dwarf_range_lists.py
4 # Examine DIE entries which have range list values, and decode these range
7 # Eli Bendersky (eliben@gmail.com)
8 # This code is in the public domain
9 #-------------------------------------------------------------------------------
10 from __future__
import print_function
13 # If elftools is not installed, maybe we're running from the root or examples
14 # dir of the source distribution
18 sys
.path
[0:0] = ['.', '..']
20 from elftools
.common
.py3compat
import itervalues
21 from elftools
.elf
.elffile
import ELFFile
22 from elftools
.dwarf
.descriptions
import (
23 describe_DWARF_expr
, set_global_machine_arch
)
24 from elftools
.dwarf
.ranges
import RangeEntry
27 def process_file(filename
):
28 print('Processing file:', filename
)
29 with
open(filename
, 'rb') as f
:
32 if not elffile
.has_dwarf_info():
33 print(' file has no DWARF info')
36 # get_dwarf_info returns a DWARFInfo context object, which is the
37 # starting point for all DWARF-based processing in pyelftools.
38 dwarfinfo
= elffile
.get_dwarf_info()
40 # The range lists are extracted by DWARFInfo from the .debug_ranges
41 # section, and returned here as a RangeLists object.
42 range_lists
= dwarfinfo
.range_lists()
44 for CU
in dwarfinfo
.iter_CUs():
45 # DWARFInfo allows to iterate over the compile units contained in
46 # the .debug_info section. CU is a CompileUnit object, with some
47 # computed attributes (such as its offset in the section) and
48 # a header which conforms to the DWARF standard. The access to
49 # header elements is, as usual, via item-lookup.
50 print(' Found a compile unit at offset %s, length %s' % (
51 CU
.cu_offset
, CU
['unit_length']))
53 # A CU provides a simple API to iterate over all the DIEs in it.
54 for DIE
in CU
.iter_DIEs():
55 # Go over all attributes of the DIE. Each attribute is an
56 # AttributeValue object (from elftools.dwarf.die), which we
58 for attr
in itervalues(DIE
.attributes
):
59 if attribute_has_range_list(attr
):
60 # This is a range list. Its value is an offset into
61 # the .debug_ranges section, so we can use the range
62 # lists object to decode it.
63 rangelist
= range_lists
.get_range_list_at_offset(
66 print(' DIE %s. attr %s.\n%s' % (
72 def attribute_has_range_list(attr
):
73 """ Only some attributes can have range list values, if they have the
74 required DW_FORM (rangelistptr "class" in DWARF spec v3)
76 if attr
.name
== 'DW_AT_ranges':
77 if attr
.form
in ('DW_FORM_data4', 'DW_FORM_data8'):
82 if __name__
== '__main__':
83 for filename
in sys
.argv
[1:]:
84 process_file(filename
)