| #------------------------------------------------------------------------------- |
| # elftools: dwarf/locationlists.py |
| # |
| # DWARF location lists section decoding (.debug_loc) |
| # |
| # Eli Bendersky (eliben@gmail.com) |
| # This code is in the public domain |
| #------------------------------------------------------------------------------- |
| import os |
| from collections import namedtuple |
| |
| from ..common.utils import struct_parse |
| |
| |
| LocationEntry = namedtuple('LocationEntry', 'begin_offset end_offset loc_expr') |
| BaseAddressEntry = namedtuple('BaseAddressEntry', 'base_address') |
| |
| |
| class LocationLists(object): |
| """ A single location list is a Python list consisting of LocationEntry or |
| BaseAddressEntry objects. |
| """ |
| def __init__(self, stream, structs): |
| self.stream = stream |
| self.structs = structs |
| self._max_addr = 2 ** (self.structs.address_size * 8) - 1 |
| |
| def get_location_list_at_offset(self, offset): |
| """ Get a location list at the given offset in the section. |
| """ |
| self.stream.seek(offset, os.SEEK_SET) |
| return self._parse_location_list_from_stream() |
| |
| def iter_location_lists(self): |
| """ Yield all location lists found in the section. |
| """ |
| # Just call _parse_location_list_from_stream until the stream ends |
| self.stream.seek(0, os.SEEK_END) |
| endpos = self.stream.tell() |
| |
| self.stream.seek(0, os.SEEK_SET) |
| while self.stream.tell() < endpos: |
| yield self._parse_location_list_from_stream() |
| |
| #------ PRIVATE ------# |
| |
| def _parse_location_list_from_stream(self): |
| lst = [] |
| while True: |
| begin_offset = struct_parse( |
| self.structs.Dwarf_target_addr(''), self.stream) |
| end_offset = struct_parse( |
| self.structs.Dwarf_target_addr(''), self.stream) |
| if begin_offset == 0 and end_offset == 0: |
| # End of list - we're done. |
| break |
| elif begin_offset == self._max_addr: |
| # Base address selection entry |
| lst.append(BaseAddressEntry(base_address=end_offset)) |
| else: |
| # Location list entry |
| expr_len = struct_parse( |
| self.structs.Dwarf_uint16(''), self.stream) |
| loc_expr = [struct_parse(self.structs.Dwarf_uint8(''), |
| self.stream) |
| for i in range(expr_len)] |
| lst.append(LocationEntry( |
| begin_offset=begin_offset, |
| end_offset=end_offset, |
| loc_expr=loc_expr)) |
| return lst |
| |
