lazy parsing of CUs
diff --git a/elftools/dwarf/dwarfinfo.py b/elftools/dwarf/dwarfinfo.py
index ff99f17..c530b43 100644
--- a/elftools/dwarf/dwarfinfo.py
+++ b/elftools/dwarf/dwarfinfo.py
@@ -80,18 +80,13 @@
dwarf_format=32,
address_size=self.config.default_address_size)
- # A list of CUs. Populated lazily when they're actually requested.
- self._CUs = None
-
# Cache for abbrev tables: a dict keyed by offset
self._abbrevtable_cache = {}
def iter_CUs(self):
""" Yield all the compile units (CompileUnit objects) in the debug info
"""
- if self._CUs is None:
- self._CUs = self._parse_CUs()
- return iter(self._CUs)
+ return self._parse_CUs_iter()
def get_abbrev_table(self, offset):
""" Get an AbbrevTable from the given offset in the debug_abbrev
@@ -151,60 +146,64 @@
#------ PRIVATE ------#
- def _parse_CUs(self):
- """ Parse CU entries from debug_info.
+ def _parse_CUs_iter(self):
+ """ Parse CU entries from debug_info. Yield CUs in order of appearance.
"""
offset = 0
- CUlist = []
while offset < self.debug_info_sec.size:
- # Section 7.4 (32-bit and 64-bit DWARF Formats) of the DWARF spec v3
- # states that the first 32-bit word of the CU header determines
- # whether the CU is represented with 32-bit or 64-bit DWARF format.
- #
- # So we peek at the first word in the CU header to determine its
- # dwarf format. Based on it, we then create a new DWARFStructs
- # instance suitable for this CU and use it to parse the rest.
- #
- initial_length = struct_parse(
- self.structs.Dwarf_uint32(''), self.debug_info_sec.stream, offset)
- dwarf_format = 64 if initial_length == 0xFFFFFFFF else 32
-
- # At this point we still haven't read the whole header, so we don't
- # know the address_size. Therefore, we're going to create structs
- # with a default address_size=4. If, after parsing the header, we
- # find out address_size is actually 8, we just create a new structs
- # object for this CU.
- #
- cu_structs = DWARFStructs(
- little_endian=self.config.little_endian,
- dwarf_format=dwarf_format,
- address_size=4)
-
- cu_header = struct_parse(
- cu_structs.Dwarf_CU_header, self.debug_info_sec.stream, offset)
- if cu_header['address_size'] == 8:
- cu_structs = DWARFStructs(
- little_endian=self.config.little_endian,
- dwarf_format=dwarf_format,
- address_size=8)
-
- cu_die_offset = self.debug_info_sec.stream.tell()
- dwarf_assert(
- self._is_supported_version(cu_header['version']),
- "Expected supported DWARF version. Got '%s'" % cu_header['version'])
- CUlist.append(CompileUnit(
- header=cu_header,
- dwarfinfo=self,
- structs=cu_structs,
- cu_offset=offset,
- cu_die_offset=cu_die_offset))
+ cu = self._parse_CU_at_offset(offset)
# Compute the offset of the next CU in the section. The unit_length
# field of the CU header contains its size not including the length
# field itself.
offset = ( offset +
- cu_header['unit_length'] +
- cu_structs.initial_length_field_size())
- return CUlist
+ cu['unit_length'] +
+ cu.structs.initial_length_field_size())
+ yield cu
+
+ def _parse_CU_at_offset(self, offset):
+ """ Parse and return a CU at the given offset in the debug_info stream.
+ """
+ # Section 7.4 (32-bit and 64-bit DWARF Formats) of the DWARF spec v3
+ # states that the first 32-bit word of the CU header determines
+ # whether the CU is represented with 32-bit or 64-bit DWARF format.
+ #
+ # So we peek at the first word in the CU header to determine its
+ # dwarf format. Based on it, we then create a new DWARFStructs
+ # instance suitable for this CU and use it to parse the rest.
+ #
+ initial_length = struct_parse(
+ self.structs.Dwarf_uint32(''), self.debug_info_sec.stream, offset)
+ dwarf_format = 64 if initial_length == 0xFFFFFFFF else 32
+
+ # At this point we still haven't read the whole header, so we don't
+ # know the address_size. Therefore, we're going to create structs
+ # with a default address_size=4. If, after parsing the header, we
+ # find out address_size is actually 8, we just create a new structs
+ # object for this CU.
+ #
+ cu_structs = DWARFStructs(
+ little_endian=self.config.little_endian,
+ dwarf_format=dwarf_format,
+ address_size=4)
+
+ cu_header = struct_parse(
+ cu_structs.Dwarf_CU_header, self.debug_info_sec.stream, offset)
+ if cu_header['address_size'] == 8:
+ cu_structs = DWARFStructs(
+ little_endian=self.config.little_endian,
+ dwarf_format=dwarf_format,
+ address_size=8)
+
+ cu_die_offset = self.debug_info_sec.stream.tell()
+ dwarf_assert(
+ self._is_supported_version(cu_header['version']),
+ "Expected supported DWARF version. Got '%s'" % cu_header['version'])
+ return CompileUnit(
+ header=cu_header,
+ dwarfinfo=self,
+ structs=cu_structs,
+ cu_offset=offset,
+ cu_die_offset=cu_die_offset)
def _is_supported_version(self, version):
""" DWARF version supported by this parser
