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"""Disassembler of Python byte code into mnemonics."""
import sys
import types
import collections
import io
from opcode import *
from opcode import __all__ as _opcodes_all
__all__ = ["code_info", "dis", "disassemble", "distb", "disco",
"findlinestarts", "findlabels", "show_code",
"get_instructions", "Instruction", "Bytecode"] + _opcodes_all
del _opcodes_all
_have_code = (types.MethodType, types.FunctionType, types.CodeType,
classmethod, staticmethod, type)
FORMAT_VALUE = opmap['FORMAT_VALUE']
def _try_compile(source, name):
"""Attempts to compile the given source, first as an expression and
then as a statement if the first approach fails.
Utility function to accept strings in functions that otherwise
expect code objects
"""
try:
c = compile(source, name, 'eval')
except SyntaxError:
c = compile(source, name, 'exec')
return c
def dis(x=None, *, file=None):
"""Disassemble classes, methods, functions, generators, or code.
With no argument, disassemble the last traceback.
"""
if x is None:
distb(file=file)
return
if hasattr(x, '__func__'): # Method
x = x.__func__
if hasattr(x, '__code__'): # Function
x = x.__code__
if hasattr(x, 'gi_code'): # Generator
x = x.gi_code
if hasattr(x, '__dict__'): # Class or module
items = sorted(x.__dict__.items())
for name, x1 in items:
if isinstance(x1, _have_code):
print("Disassembly of %s:" % name, file=file)
try:
dis(x1, file=file)
except TypeError as msg:
print("Sorry:", msg, file=file)
print(file=file)
elif hasattr(x, 'co_code'): # Code object
disassemble(x, file=file)
elif isinstance(x, (bytes, bytearray)): # Raw bytecode
_disassemble_bytes(x, file=file)
elif isinstance(x, str): # Source code
_disassemble_str(x, file=file)
else:
raise TypeError("don't know how to disassemble %s objects" %
type(x).__name__)
def distb(tb=None, *, file=None):
"""Disassemble a traceback (default: last traceback)."""
if tb is None:
try:
tb = sys.last_traceback
except AttributeError:
raise RuntimeError("no last traceback to disassemble")
while tb.tb_next: tb = tb.tb_next
disassemble(tb.tb_frame.f_code, tb.tb_lasti, file=file)
# The inspect module interrogates this dictionary to build its
# list of CO_* constants. It is also used by pretty_flags to
# turn the co_flags field into a human readable list.
COMPILER_FLAG_NAMES = {
1: "OPTIMIZED",
2: "NEWLOCALS",
4: "VARARGS",
8: "VARKEYWORDS",
16: "NESTED",
32: "GENERATOR",
64: "NOFREE",
128: "COROUTINE",
256: "ITERABLE_COROUTINE",
512: "ASYNC_GENERATOR",
}
def pretty_flags(flags):
"""Return pretty representation of code flags."""
names = []
for i in range(32):
flag = 1= 1000?
lineno_width = 3 if show_lineno else 0
for instr in _get_instructions_bytes(code, varnames, names,
constants, cells, linestarts,
line_offset=line_offset):
new_source_line = (show_lineno and
instr.starts_line is not None and
instr.offset > 0)
if new_source_line:
print(file=file)
is_current_instr = instr.offset == lasti
print(instr._disassemble(lineno_width, is_current_instr), file=file)
def _disassemble_str(source, *, file=None):
"""Compile the source string, then disassemble the code object."""
disassemble(_try_compile(source, ''), file=file)
disco = disassemble # XXX For backwards compatibility
def _unpack_opargs(code):
extended_arg = 0
for i in range(0, len(code), 2):
op = code[i]
if op >= HAVE_ARGUMENT:
arg = code[i+1] | extended_arg
extended_arg = (arg = 0x80:
# line_increments is an array of 8-bit signed integers
line_incr -= 0x100
lineno += line_incr
if lineno != lastlineno:
yield (addr, lineno)
class Bytecode:
"""The bytecode operations of a piece of code
Instantiate this with a function, method, string of code, or a code object
(as returned by compile()).
Iterating over this yields the bytecode operations as Instruction instances.
"""
def __init__(self, x, *, first_line=None, current_offset=None):
self.codeobj = co = _get_code_object(x)
if first_line is None:
self.first_line = co.co_firstlineno
self._line_offset = 0
else:
self.first_line = first_line
self._line_offset = first_line - co.co_firstlineno
self._cell_names = co.co_cellvars + co.co_freevars
self._linestarts = dict(findlinestarts(co))
self._original_object = x
self.current_offset = current_offset
def __iter__(self):
co = self.codeobj
return _get_instructions_bytes(co.co_code, co.co_varnames, co.co_names,
co.co_consts, self._cell_names,
self._linestarts,
line_offset=self._line_offset)
def __repr__(self):
return "{}({!r})".format(self.__class__.__name__,
self._original_object)
@classmethod
def from_traceback(cls, tb):
""" Construct a Bytecode from the given traceback """
while tb.tb_next:
tb = tb.tb_next
return cls(tb.tb_frame.f_code, current_offset=tb.tb_lasti)
def info(self):
"""Return formatted information about the code object."""
return _format_code_info(self.codeobj)
def dis(self):
"""Return a formatted view of the bytecode operations."""
co = self.codeobj
if self.current_offset is not None:
offset = self.current_offset
else:
offset = -1
with io.StringIO() as output:
_disassemble_bytes(co.co_code, varnames=co.co_varnames,
names=co.co_names, constants=co.co_consts,
cells=self._cell_names,
linestarts=self._linestarts,
line_offset=self._line_offset,
file=output,
lasti=offset)
return output.getvalue()
def _test():
"""Simple test program to disassemble a file."""
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('infile', type=argparse.FileType(), nargs='?', default='-')
args = parser.parse_args()
with args.infile as infile:
source = infile.read()
code = compile(source, args.infile.name, "exec")
dis(code)
if __name__ == "__main__":
_test()