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Editing: dis.py
"""Disassembler of Python byte code into mnemonics.""" import sys import types from opcode import * from opcode import __all__ as _opcodes_all __all__ = ["dis", "disassemble", "distb", "disco", "findlinestarts", "findlabels"] + _opcodes_all del _opcodes_all _have_code = (types.MethodType, types.FunctionType, types.CodeType, types.ClassType, type) def dis(x=None): """Disassemble classes, methods, functions, or code. With no argument, disassemble the last traceback. """ if x is None: distb() return if isinstance(x, types.InstanceType): x = x.__class__ if hasattr(x, 'im_func'): x = x.im_func if hasattr(x, 'func_code'): x = x.func_code if hasattr(x, '__dict__'): items = x.__dict__.items() items.sort() for name, x1 in items: if isinstance(x1, _have_code): print "Disassembly of %s:" % name try: dis(x1) except TypeError, msg: print "Sorry:", msg print elif hasattr(x, 'co_code'): disassemble(x) elif isinstance(x, str): disassemble_string(x) else: raise TypeError, \ "don't know how to disassemble %s objects" % \ type(x).__name__ def distb(tb=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) def disassemble(co, lasti=-1): """Disassemble a code object.""" code = co.co_code labels = findlabels(code) linestarts = dict(findlinestarts(co)) n = len(code) i = 0 extended_arg = 0 free = None while i < n: c = code[i] op = ord(c) if i in linestarts: if i > 0: print print "%3d" % linestarts[i], else: print ' ', if i == lasti: print '-->', else: print ' ', if i in labels: print '>>', else: print ' ', print repr(i).rjust(4), print opname[op].ljust(20), i = i+1 if op >= HAVE_ARGUMENT: oparg = ord(code[i]) + ord(code[i+1])*256 + extended_arg extended_arg = 0 i = i+2 if op == EXTENDED_ARG: extended_arg = oparg*65536L print repr(oparg).rjust(5), if op in hasconst: print '(' + repr(co.co_consts[oparg]) + ')', elif op in hasname: print '(' + co.co_names[oparg] + ')', elif op in hasjrel: print '(to ' + repr(i + oparg) + ')', elif op in haslocal: print '(' + co.co_varnames[oparg] + ')', elif op in hascompare: print '(' + cmp_op[oparg] + ')', elif op in hasfree: if free is None: free = co.co_cellvars + co.co_freevars print '(' + free[oparg] + ')', print def disassemble_string(code, lasti=-1, varnames=None, names=None, constants=None): labels = findlabels(code) n = len(code) i = 0 while i < n: c = code[i] op = ord(c) if i == lasti: print '-->', else: print ' ', if i in labels: print '>>', else: print ' ', print repr(i).rjust(4), print opname[op].ljust(15), i = i+1 if op >= HAVE_ARGUMENT: oparg = ord(code[i]) + ord(code[i+1])*256 i = i+2 print repr(oparg).rjust(5), if op in hasconst: if constants: print '(' + repr(constants[oparg]) + ')', else: print '(%d)'%oparg, elif op in hasname: if names is not None: print '(' + names[oparg] + ')', else: print '(%d)'%oparg, elif op in hasjrel: print '(to ' + repr(i + oparg) + ')', elif op in haslocal: if varnames: print '(' + varnames[oparg] + ')', else: print '(%d)' % oparg, elif op in hascompare: print '(' + cmp_op[oparg] + ')', print disco = disassemble # XXX For backwards compatibility def findlabels(code): """Detect all offsets in a byte code which are jump targets. Return the list of offsets. """ labels = [] n = len(code) i = 0 while i < n: c = code[i] op = ord(c) i = i+1 if op >= HAVE_ARGUMENT: oparg = ord(code[i]) + ord(code[i+1])*256 i = i+2 label = -1 if op in hasjrel: label = i+oparg elif op in hasjabs: label = oparg if label >= 0: if label not in labels: labels.append(label) return labels def findlinestarts(code): """Find the offsets in a byte code which are start of lines in the source. Generate pairs (offset, lineno) as described in Python/compile.c. """ byte_increments = [ord(c) for c in code.co_lnotab[0::2]] line_increments = [ord(c) for c in code.co_lnotab[1::2]] lastlineno = None lineno = code.co_firstlineno addr = 0 for byte_incr, line_incr in zip(byte_increments, line_increments): if byte_incr: if lineno != lastlineno: yield (addr, lineno) lastlineno = lineno addr += byte_incr lineno += line_incr if lineno != lastlineno: yield (addr, lineno) def _test(): """Simple test program to disassemble a file.""" if sys.argv[1:]: if sys.argv[2:]: sys.stderr.write("usage: python dis.py [-|file]\n") sys.exit(2) fn = sys.argv[1] if not fn or fn == "-": fn = None else: fn = None if fn is None: f = sys.stdin else: f = open(fn) source = f.read() if fn is not None: f.close() else: fn = "<stdin>" code = compile(source, fn, "exec") dis(code) if __name__ == "__main__": _test()
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