changed the method to obtain line programs - now per CU
diff --git a/elftools/dwarf/dwarfinfo.py b/elftools/dwarf/dwarfinfo.py
index 90ba52a..8ebb47d 100644
--- a/elftools/dwarf/dwarfinfo.py
+++ b/elftools/dwarf/dwarfinfo.py
@@ -68,10 +68,6 @@
# Cache for abbrev tables: a dict keyed by offset
self._abbrevtable_cache = {}
-
- # A list of parsed line programs. Populated lazily when the line
- # programs are actually requested
- self._lineprograms = None
def iter_CUs(self):
""" Yield all the compile units (CompileUnit objects) in the debug info
@@ -80,13 +76,6 @@
self._CUs = self._parse_CUs()
return iter(self._CUs)
- def iter_line_programs(self):
- """ Yield all the line programs (LineProgram ojects) in the debug info
- """
- if self._lineprograms is None:
- self._lineprograms = self._parse_line_programs()
- return iter(self._lineprograms)
-
def get_abbrev_table(self, offset):
""" Get an AbbrevTable from the given offset in the debug_abbrev
section.
@@ -115,6 +104,20 @@
"""
return parse_cstring_from_stream(self.debug_str_sec.stream, offset)
+ def line_program_for_CU(self, CU):
+ """ Given a CU object, fetch the line program it points to from the
+ .debug_line section.
+ If the CU doesn't point to a line program, return None.
+ """
+ # The line program is pointed to by the DW_AT_stmt_list attribute of
+ # the top DIE of a CU.
+ top_DIE = CU.get_top_DIE()
+ if 'DW_AT_stmt_list' in top_DIE.attributes:
+ return self._parse_line_program_at_offset(
+ top_DIE.attributes['DW_AT_stmt_list'], CU.structs)
+ else:
+ return None
+
#------ PRIVATE ------#
def _parse_CUs(self):
@@ -177,48 +180,24 @@
"""
return 2 <= version <= 3
- def _parse_line_programs(self):
- """ Parse line programs from debug_line
+ def _parse_line_program_at_offset(self, debug_line_offset, structs):
+ """ Given an offset to the .debug_line section, parse the line program
+ starting at this offset in the section and return it.
+ structs is the DWARFStructs object used to do this parsing.
"""
- offset = 0
- lineprograms = []
- while offset < self.debug_line_sec.size:
- # Similarly to CU parsing, peek at the initial_length field of the
- # header to figure out the DWARF format for it.
- initial_length = struct_parse(
- self.structs.Dwarf_uint32(''),
- self.debug_line_sec.stream,
- offset)
- dwarf_format = 64 if initial_length == 0xFFFFFFFF else 32
+ lineprog_header = struct_parse(
+ structs.Dwarf_lineprog_header,
+ self.debug_line_sec.stream,
+ offset)
- # Prepare the structs for this line program, based on its format
- # and the default endianness. The address_size plays no role for
- # line programs so we just give it a default value.
- lineprog_structs = DWARFStructs(
- little_endian=self.little_endian,
- dwarf_format=dwarf_format,
- address_size=4)
+ # Calculate the offset to the next line program (see DWARF 6.2.4)
+ end_offset = ( offset + lineprog_header['unit_length'] +
+ lineprog_structs.initial_length_field_size())
- # Now parse the header fully using up-to-date structs. After this,
- # the section stream will point at the beginning of the program
- # itself, right after the header.
- lineprog_header = struct_parse(
- lineprog_structs.Dwarf_lineprog_header,
- self.debug_line_sec.stream,
- offset)
-
- # Calculate the offset to the next line program (see DWARF 6.2.4)
- end_offset = ( offset + lineprog_header['unit_length'] +
- lineprog_structs.initial_length_field_size()))
-
- lineprograms.append(LineProgram(
- header=lineprog_header,
- dwarfinfo=self,
- structs=lineprog_structs,
- program_start_offset=self.debug_line_sec.stream.tell()),
- program_end_offset=end_offset)
-
- offset = end_offset
-
- return lineprograms
+ return LineProgram(
+ header=lineprog_header,
+ dwarfinfo=self,
+ structs=lineprog_structs,
+ program_start_offset=self.debug_line_sec.stream.tell(),
+ program_end_offset=end_offset)
diff --git a/elftools/dwarf/lineprogram.py b/elftools/dwarf/lineprogram.py
index ce92075..43d8f90 100644
--- a/elftools/dwarf/lineprogram.py
+++ b/elftools/dwarf/lineprogram.py
@@ -13,6 +13,8 @@
class LineState(object):
""" Represents a line program state (or a "row" in the matrix
describing debug location information for addresses).
+ The instance variables of this class are the "state machine registers"
+ described in section 6.2.2 of DWARFv3
"""
def __init__(self, default_is_stmt):
self.address = 0
@@ -37,7 +39,9 @@
program_start_offset, program_end_offset):
"""
header:
- The header of this line program
+ The header of this line program. Note: LineProgram may modify
+ its header by appending file entries if DW_LNE_define_file
+ instructions are encountered.
dwarfinfo:
The DWARFInfo context object which created this one
@@ -77,6 +81,15 @@
linetable = []
state = LineState(self.header['default_is_stmt'])
+ def add_state_to_table():
+ # Used by instructions that have to add the current state to the
+ # line table. After adding, some state registers have to be
+ # cleared.
+ linetable.append(state)
+ state.basic_block = False
+ state.prologue_end = False
+ state.epilogue_begin = False
+
offset = self.program_start_offset
while offset < self.program_end_offset:
opcode = struct_parse(
@@ -87,30 +100,69 @@
# As an exercise in avoiding premature optimization, if...elif
# chains are used here for standard and extended opcodes instead
# of dispatch tables. This keeps the code much cleaner. Besides,
- # the majority of instructions are special opcodes anyway.
- if opcode == 0:
+ # the majority of instructions in a typical program are special
+ # opcodes anyway.
+ if opcode >= self.header['opcode_base']:
+ # Special opcode (follow the recipe in 6.2.5.1)
+ adjusted_opcode = opcode - self['opcode_base']
+ state.address += ((adjusted_opcode / self['line_range']) *
+ self['minimum_instruction_length'])
+ self.line += (self['line_base'] +
+ adjusted_opcode % self['line_range'])
+ add_state_to_table()
+ elif opcode == 0:
# Extended opcode: start with a zero byte, followed by
# instruction size and the instruction itself.
- pass
- elif opcode < self.header['opcode_base']:
+ inst_len = struct_parse(self.Dwarf_uleb128, self.stream)
+ ex_opcode = struct_parse(self.Dwarf_uint8, self.stream)
+
+ if ex_opcode == DW_LNE_end_sequence:
+ state.end_sequence = True
+ add_state_to_table(state)
+ state = LineState() # reset state
+ elif ex_opcode == DW_LNE_set_address:
+ operand = struct_parse(self.Dwarf_target_addr, self.stream)
+ state.address = operand
+ elif ex_opcode == DW_LNE_define_file:
+ operand = struct_parse(self.Dwarf_lineprog_file_entry,
+ self.stream)
+ self['file_entry'].append(operand)
+ else: # 0 < opcode < opcode_base
# Standard opcode
if opcode == DW_LNS_copy:
- linetable.append(state)
- state.basic_block = False
- state.prologue_end = False
- state.epilogue_begin = False
+ add_state_to_table()
elif opcode == DW_LNS_advance_pc:
operand = struct_parse(self.Dwarf_uleb128, self.stream)
state.address += (
operand * self.header['minimum_instruction_length'])
- elif opcode = DW_LNS_advance_line:
+ elif opcode == DW_LNS_advance_line:
operand = struct_parse(self.Dwarf_sleb128, self.stream)
state.line += operand
- # ZZZ! go on now...
- else:
- # Special opcode
- pass
-
- def _handle_LNS_copy(self, opcode, state, linetable):
- pass
+ elif opcode == DW_LNS_set_file:
+ operand = struct_parse(self.Dwarf_sleb128, self.stream)
+ state.file = operand
+ elif opcode == DW_LNS_set_column:
+ operand = struct_parse(self.Dwarf_uleb128, self.stream)
+ state.column = operand
+ elif opcode == DW_LNS_negate_stmt:
+ state.is_stmt = not state.is_stmt
+ elif opcode == DW_LNS_set_basic_block:
+ state.basic_block = True
+ elif opcode == DW_LNS_const_add_pc:
+ adjusted_opcode = 255 - self['opcode_base']
+ state.address += ((adjusted_opcode / self['line_range']) *
+ self['minimum_instruction_length'])
+ elif opcode == DW_LNS_fixed_advance_pc:
+ operand = struct_parse(self.Dwarf_uint16, self.stream)
+ state.address += operand
+ elif opcode == DW_LNS_set_prologue_end:
+ state.prologue_end = True
+ elif opcode == DW_LNS_set_epilogue_begin:
+ state.epilogue_begin = True
+ elif opcode == DW_LNS_set_isa:
+ operand = struct_parse(self.Dwarf_uleb128, self.stream)
+ state.isa = operand
+ else:
+ dwarf_assert(False, 'Invalid standard line program opcode: %s' % (
+ opcode,))
diff --git a/elftools/dwarf/structs.py b/elftools/dwarf/structs.py
index 6d71657..ebf34c6 100644
--- a/elftools/dwarf/structs.py
+++ b/elftools/dwarf/structs.py
@@ -59,6 +59,9 @@
Dwarf_lineprog_header (+):
Line program header
+
+ Dwarf_lineprog_file_entry (+):
+ A single file entry in a line program header or instruction
See also the documentation of public methods.
"""
@@ -188,7 +191,7 @@
def _create_lineprog_header(self):
# A file entry is terminated by a NULL byte, so we don't want to parse
# past it. Therefore an If is used.
- file_entry = Struct('file_entry',
+ self.Dwarf_lineprog_file_entry = Struct('file_entry',
CString('name'),
If(lambda ctx: len(ctx.name) != 0,
Embed(Struct('',
@@ -212,7 +215,7 @@
CString('include_directory')),
RepeatUntilExcluding(
lambda obj, ctx: len(obj.name) == 0,
- file_entry),
+ self.Dwarf_lineprog_file_entry),
)
def _make_block_struct(self, length_field):
diff --git a/z.py b/z.py
index 4bf3709..f603948 100644
--- a/z.py
+++ b/z.py
@@ -23,7 +23,7 @@
dwarfinfo = efile.get_dwarf_info()
-for lp in dwarfinfo.iter_line_programs():
- print lp
- print lp.header
+#for lp in dwarfinfo.iter_line_programs():
+ #print lp
+ #print lp.header
