1 """Disassembler of Python byte code into mnemonics.""" 2 3 import sys 4 import types 5 6 from opcode import * 7 from opcode import __all__ as _opcodes_all 8 9 __all__ = ["dis", "disassemble", "distb", "disco", 10 "findlinestarts", "findlabels"] + _opcodes_all 11 del _opcodes_all 12 13 _have_code = (types.MethodType, types.FunctionType, types.CodeType, 14 types.ClassType, type) 15 16 def dis(x=None): 17 """Disassemble classes, methods, functions, or code. 18 19 With no argument, disassemble the last traceback. 20 21 """ 22 if x is None: 23 distb() 24 return 25 if isinstance(x, types.InstanceType): 26 x = x.__class__ 27 if hasattr(x, 'im_func'): 28 x = x.im_func 29 if hasattr(x, 'func_code'): 30 x = x.func_code 31 if hasattr(x, '__dict__'): 32 items = x.__dict__.items() 33 items.sort() 34 for name, x1 in items: 35 if isinstance(x1, _have_code): 36 print "Disassembly of %s:" % name 37 try: 38 dis(x1) 39 except TypeError, msg: 40 print "Sorry:", msg 41 print 42 elif hasattr(x, 'co_code'): 43 disassemble(x) 44 elif isinstance(x, str): 45 disassemble_string(x) 46 else: 47 raise TypeError, \ 48 "don't know how to disassemble %s objects" % \ 49 type(x).__name__ 50 51 def distb(tb=None): 52 """Disassemble a traceback (default: last traceback).""" 53 if tb is None: 54 try: 55 tb = sys.last_traceback 56 except AttributeError: 57 raise RuntimeError, "no last traceback to disassemble" 58 while tb.tb_next: tb = tb.tb_next 59 disassemble(tb.tb_frame.f_code, tb.tb_lasti) 60 61 def disassemble(co, lasti=-1): 62 """Disassemble a code object.""" 63 code = co.co_code 64 labels = findlabels(code) 65 linestarts = dict(findlinestarts(co)) 66 n = len(code) 67 i = 0 68 extended_arg = 0 69 free = None 70 while i < n: 71 c = code[i] 72 op = ord(c) 73 if i in linestarts: 74 if i > 0: 75 print 76 print "%3d" % linestarts[i], 77 else: 78 print ' ', 79 80 if i == lasti: print '-->', 81 else: print ' ', 82 if i in labels: print '>>', 83 else: print ' ', 84 print repr(i).rjust(4), 85 print opname[op].ljust(20), 86 i = i+1 87 if op >= HAVE_ARGUMENT: 88 oparg = ord(code[i]) + ord(code[i+1])*256 + extended_arg 89 extended_arg = 0 90 i = i+2 91 if op == EXTENDED_ARG: 92 extended_arg = oparg*65536L 93 print repr(oparg).rjust(5), 94 if op in hasconst: 95 print '(' + repr(co.co_consts[oparg]) + ')', 96 elif op in hasname: 97 print '(' + co.co_names[oparg] + ')', 98 elif op in hasjrel: 99 print '(to ' + repr(i + oparg) + ')', 100 elif op in haslocal: 101 print '(' + co.co_varnames[oparg] + ')', 102 elif op in hascompare: 103 print '(' + cmp_op[oparg] + ')', 104 elif op in hasfree: 105 if free is None: 106 free = co.co_cellvars + co.co_freevars 107 print '(' + free[oparg] + ')', 108 print 109 110 def disassemble_string(code, lasti=-1, varnames=None, names=None, 111 constants=None): 112 labels = findlabels(code) 113 n = len(code) 114 i = 0 115 while i < n: 116 c = code[i] 117 op = ord(c) 118 if i == lasti: print '-->', 119 else: print ' ', 120 if i in labels: print '>>', 121 else: print ' ', 122 print repr(i).rjust(4), 123 print opname[op].ljust(15), 124 i = i+1 125 if op >= HAVE_ARGUMENT: 126 oparg = ord(code[i]) + ord(code[i+1])*256 127 i = i+2 128 print repr(oparg).rjust(5), 129 if op in hasconst: 130 if constants: 131 print '(' + repr(constants[oparg]) + ')', 132 else: 133 print '(%d)'%oparg, 134 elif op in hasname: 135 if names is not None: 136 print '(' + names[oparg] + ')', 137 else: 138 print '(%d)'%oparg, 139 elif op in hasjrel: 140 print '(to ' + repr(i + oparg) + ')', 141 elif op in haslocal: 142 if varnames: 143 print '(' + varnames[oparg] + ')', 144 else: 145 print '(%d)' % oparg, 146 elif op in hascompare: 147 print '(' + cmp_op[oparg] + ')', 148 print 149 150 disco = disassemble # XXX For backwards compatibility 151 152 def findlabels(code): 153 """Detect all offsets in a byte code which are jump targets. 154 155 Return the list of offsets. 156 157 """ 158 labels = [] 159 n = len(code) 160 i = 0 161 while i < n: 162 c = code[i] 163 op = ord(c) 164 i = i+1 165 if op >= HAVE_ARGUMENT: 166 oparg = ord(code[i]) + ord(code[i+1])*256 167 i = i+2 168 label = -1 169 if op in hasjrel: 170 label = i+oparg 171 elif op in hasjabs: 172 label = oparg 173 if label >= 0: 174 if label not in labels: 175 labels.append(label) 176 return labels 177 178 def findlinestarts(code): 179 """Find the offsets in a byte code which are start of lines in the source. 180 181 Generate pairs (offset, lineno) as described in Python/compile.c. 182 183 """ 184 byte_increments = [ord(c) for c in code.co_lnotab[0::2]] 185 line_increments = [ord(c) for c in code.co_lnotab[1::2]] 186 187 lastlineno = None 188 lineno = code.co_firstlineno 189 addr = 0 190 for byte_incr, line_incr in zip(byte_increments, line_increments): 191 if byte_incr: 192 if lineno != lastlineno: 193 yield (addr, lineno) 194 lastlineno = lineno 195 addr += byte_incr 196 lineno += line_incr 197 if lineno != lastlineno: 198 yield (addr, lineno) 199 200 def _test(): 201 """Simple test program to disassemble a file.""" 202 if sys.argv[1:]: 203 if sys.argv[2:]: 204 sys.stderr.write("usage: python dis.py [-|file]\n") 205 sys.exit(2) 206 fn = sys.argv[1] 207 if not fn or fn == "-": 208 fn = None 209 else: 210 fn = None 211 if fn is None: 212 f = sys.stdin 213 else: 214 f = open(fn) 215 source = f.read() 216 if fn is not None: 217 f.close() 218 else: 219 fn = "<stdin>" 220 code = compile(source, fn, "exec") 221 dis(code) 222 223 if __name__ == "__main__": 224 _test() 225
