summaryrefslogtreecommitdiffstats
path: root/Doc/library/dis.rst
blob: cb429c880c161d72c712e5af701748dfc9207f23 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
:mod:`dis` --- Disassembler for Python bytecode
===============================================

.. module:: dis
   :synopsis: Disassembler for Python bytecode.

**Source code:** :source:`Lib/dis.py`

--------------

The :mod:`dis` module supports the analysis of CPython :term:`bytecode` by
disassembling it. The CPython bytecode which this module takes as an
input is defined in the file :file:`Include/opcode.h` and used by the compiler
and the interpreter.

.. impl-detail::

   Bytecode is an implementation detail of the CPython interpreter.  No
   guarantees are made that bytecode will not be added, removed, or changed
   between versions of Python.  Use of this module should not be considered to
   work across Python VMs or Python releases.


Example: Given the function :func:`myfunc`::

   def myfunc(alist):
       return len(alist)

the following command can be used to get the disassembly of :func:`myfunc`::

   >>> dis.dis(myfunc)
     2           0 LOAD_GLOBAL              0 (len)
                 3 LOAD_FAST                0 (alist)
                 6 CALL_FUNCTION            1
                 9 RETURN_VALUE

(The "2" is a line number).

The :mod:`dis` module defines the following functions and constants:


.. function:: code_info(x)

   Return a formatted multi-line string with detailed code object information
   for the supplied function, method, source code string or code object.

   Note that the exact contents of code info strings are highly implementation
   dependent and they may change arbitrarily across Python VMs or Python
   releases.

   .. versionadded:: 3.2


.. function:: show_code(x)

   Print detailed code object information for the supplied function, method,
   source code string or code object to stdout.

   This is a convenient shorthand for ``print(code_info(x))``, intended for
   interactive exploration at the interpreter prompt.

   .. versionadded:: 3.2

.. function:: dis(x=None)

   Disassemble the *x* object.  *x* can denote either a module, a class, a
   method, a function, a code object, a string of source code or a byte sequence
   of raw bytecode.  For a module, it disassembles all functions.  For a class,
   it disassembles all methods.  For a code object or sequence of raw bytecode,
   it prints one line per bytecode instruction.  Strings are first compiled to
   code objects with the :func:`compile` built-in function before being
   disassembled.  If no object is provided, this function disassembles the last
   traceback.


.. function:: distb(tb=None)

   Disassemble the top-of-stack function of a traceback, using the last
   traceback if none was passed.  The instruction causing the exception is
   indicated.


.. function:: disassemble(code, lasti=-1)
              disco(code, lasti=-1)

   Disassemble a code object, indicating the last instruction if *lasti* was
   provided.  The output is divided in the following columns:

   #. the line number, for the first instruction of each line
   #. the current instruction, indicated as ``-->``,
   #. a labelled instruction, indicated with ``>>``,
   #. the address of the instruction,
   #. the operation code name,
   #. operation parameters, and
   #. interpretation of the parameters in parentheses.

   The parameter interpretation recognizes local and global variable names,
   constant values, branch targets, and compare operators.


.. function:: findlinestarts(code)

   This generator function uses the ``co_firstlineno`` and ``co_lnotab``
   attributes of the code object *code* to find the offsets which are starts of
   lines in the source code.  They are generated as ``(offset, lineno)`` pairs.


.. function:: findlabels(code)

   Detect all offsets in the code object *code* which are jump targets, and
   return a list of these offsets.


.. data:: opname

   Sequence of operation names, indexable using the bytecode.


.. data:: opmap

   Dictionary mapping operation names to bytecodes.


.. data:: cmp_op

   Sequence of all compare operation names.


.. data:: hasconst

   Sequence of bytecodes that have a constant parameter.


.. data:: hasfree

   Sequence of bytecodes that access a free variable.


.. data:: hasname

   Sequence of bytecodes that access an attribute by name.


.. data:: hasjrel

   Sequence of bytecodes that have a relative jump target.


.. data:: hasjabs

   Sequence of bytecodes that have an absolute jump target.


.. data:: haslocal

   Sequence of bytecodes that access a local variable.


.. data:: hascompare

   Sequence of bytecodes of Boolean operations.


.. _bytecodes:

Python Bytecode Instructions
----------------------------

The Python compiler currently generates the following bytecode instructions.


**General instructions**

.. opcode:: NOP

   Do nothing code.  Used as a placeholder by the bytecode optimizer.


.. opcode:: POP_TOP

   Removes the top-of-stack (TOS) item.


.. opcode:: ROT_TWO

   Swaps the two top-most stack items.


.. opcode:: ROT_THREE

   Lifts second and third stack item one position up, moves top down to position
   three.


.. opcode:: DUP_TOP

   Duplicates the reference on top of the stack.


.. opcode:: DUP_TOP_TWO

   Duplicates the two references on top of the stack, leaving them in the
   same order.


**Unary operations**

Unary operations take the top of the stack, apply the operation, and push the
result back on the stack.

.. opcode:: UNARY_POSITIVE

   Implements ``TOS = +TOS``.


.. opcode:: UNARY_NEGATIVE

   Implements ``TOS = -TOS``.


.. opcode:: UNARY_NOT

   Implements ``TOS = not TOS``.


.. opcode:: UNARY_INVERT

   Implements ``TOS = ~TOS``.


.. opcode:: GET_ITER

   Implements ``TOS = iter(TOS)``.


**Binary operations**

Binary operations remove the top of the stack (TOS) and the second top-most
stack item (TOS1) from the stack.  They perform the operation, and put the
result back on the stack.

.. opcode:: BINARY_POWER

   Implements ``TOS = TOS1 ** TOS``.


.. opcode:: BINARY_MULTIPLY

   Implements ``TOS = TOS1 * TOS``.


.. opcode:: BINARY_FLOOR_DIVIDE

   Implements ``TOS = TOS1 // TOS``.


.. opcode:: BINARY_TRUE_DIVIDE

   Implements ``TOS = TOS1 / TOS``.


.. opcode:: BINARY_MODULO

   Implements ``TOS = TOS1 % TOS``.


.. opcode:: BINARY_ADD

   Implements ``TOS = TOS1 + TOS``.


.. opcode:: BINARY_SUBTRACT

   Implements ``TOS = TOS1 - TOS``.


.. opcode:: BINARY_SUBSCR

   Implements ``TOS = TOS1[TOS]``.


.. opcode:: BINARY_LSHIFT

   Implements ``TOS = TOS1 << TOS``.


.. opcode:: BINARY_RSHIFT

   Implements ``TOS = TOS1 >> TOS``.


.. opcode:: BINARY_AND

   Implements ``TOS = TOS1 & TOS``.


.. opcode:: BINARY_XOR

   Implements ``TOS = TOS1 ^ TOS``.


.. opcode:: BINARY_OR

   Implements ``TOS = TOS1 | TOS``.


**In-place operations**

In-place operations are like binary operations, in that they remove TOS and
TOS1, and push the result back on the stack, but the operation is done in-place
when TOS1 supports it, and the resulting TOS may be (but does not have to be)
the original TOS1.

.. opcode:: INPLACE_POWER

   Implements in-place ``TOS = TOS1 ** TOS``.


.. opcode:: INPLACE_MULTIPLY

   Implements in-place ``TOS = TOS1 * TOS``.


.. opcode:: INPLACE_FLOOR_DIVIDE

   Implements in-place ``TOS = TOS1 // TOS``.


.. opcode:: INPLACE_TRUE_DIVIDE

   Implements in-place ``TOS = TOS1 / TOS``.


.. opcode:: INPLACE_MODULO

   Implements in-place ``TOS = TOS1 % TOS``.


.. opcode:: INPLACE_ADD

   Implements in-place ``TOS = TOS1 + TOS``.


.. opcode:: INPLACE_SUBTRACT

   Implements in-place ``TOS = TOS1 - TOS``.


.. opcode:: INPLACE_LSHIFT

   Implements in-place ``TOS = TOS1 << TOS``.


.. opcode:: INPLACE_RSHIFT

   Implements in-place ``TOS = TOS1 >> TOS``.


.. opcode:: INPLACE_AND

   Implements in-place ``TOS = TOS1 & TOS``.


.. opcode:: INPLACE_XOR

   Implements in-place ``TOS = TOS1 ^ TOS``.


.. opcode:: INPLACE_OR

   Implements in-place ``TOS = TOS1 | TOS``.


.. opcode:: STORE_SUBSCR

   Implements ``TOS1[TOS] = TOS2``.


.. opcode:: DELETE_SUBSCR

   Implements ``del TOS1[TOS]``.


**Miscellaneous opcodes**

.. opcode:: PRINT_EXPR

   Implements the expression statement for the interactive mode.  TOS is removed
   from the stack and printed.  In non-interactive mode, an expression statement is
   terminated with ``POP_STACK``.


.. opcode:: BREAK_LOOP

   Terminates a loop due to a :keyword:`break` statement.


.. opcode:: CONTINUE_LOOP (target)

   Continues a loop due to a :keyword:`continue` statement.  *target* is the
   address to jump to (which should be a ``FOR_ITER`` instruction).


.. opcode:: SET_ADD (i)

   Calls ``set.add(TOS1[-i], TOS)``.  Used to implement set comprehensions.


.. opcode:: LIST_APPEND (i)

   Calls ``list.append(TOS[-i], TOS)``.  Used to implement list comprehensions.


.. opcode:: MAP_ADD (i)

   Calls ``dict.setitem(TOS1[-i], TOS, TOS1)``.  Used to implement dict
   comprehensions.

For all of the SET_ADD, LIST_APPEND and MAP_ADD instructions, while the
added value or key/value pair is popped off, the container object remains on
the stack so that it is available for further iterations of the loop.


.. opcode:: RETURN_VALUE

   Returns with TOS to the caller of the function.


.. opcode:: YIELD_VALUE

   Pops ``TOS`` and yields it from a :term:`generator`.


.. opcode:: IMPORT_STAR

   Loads all symbols not starting with ``'_'`` directly from the module TOS to the
   local namespace. The module is popped after loading all names. This opcode
   implements ``from module import *``.


.. opcode:: POP_BLOCK

   Removes one block from the block stack.  Per frame, there is a  stack of blocks,
   denoting nested loops, try statements, and such.


.. opcode:: POP_EXCEPT

   Removes one block from the block stack. The popped block must be an exception
   handler block, as implicitly created when entering an except handler.
   In addition to popping extraneous values from the frame stack, the
   last three popped values are used to restore the exception state.


.. opcode:: END_FINALLY

   Terminates a :keyword:`finally` clause.  The interpreter recalls whether the
   exception has to be re-raised, or whether the function returns, and continues
   with the outer-next block.


.. opcode:: LOAD_BUILD_CLASS

   Pushes :func:`builtins.__build_class__` onto the stack.  It is later called
   by ``CALL_FUNCTION`` to construct a class.


.. opcode:: SETUP_WITH (delta)

   This opcode performs several operations before a with block starts.  First,
   it loads :meth:`~object.__exit__` from the context manager and pushes it onto
   the stack for later use by :opcode:`WITH_CLEANUP`.  Then,
   :meth:`~object.__enter__` is called, and a finally block pointing to *delta*
   is pushed.  Finally, the result of calling the enter method is pushed onto
   the stack.  The next opcode will either ignore it (:opcode:`POP_TOP`), or
   store it in (a) variable(s) (:opcode:`STORE_FAST`, :opcode:`STORE_NAME`, or
   :opcode:`UNPACK_SEQUENCE`).


.. opcode:: WITH_CLEANUP

   Cleans up the stack when a :keyword:`with` statement block exits.  TOS is
   the context manager's :meth:`__exit__` bound method. Below TOS are 1--3
   values indicating how/why the finally clause was entered:

   * SECOND = ``None``
   * (SECOND, THIRD) = (``WHY_{RETURN,CONTINUE}``), retval
   * SECOND = ``WHY_*``; no retval below it
   * (SECOND, THIRD, FOURTH) = exc_info()

   In the last case, ``TOS(SECOND, THIRD, FOURTH)`` is called, otherwise
   ``TOS(None, None, None)``.  In addition, TOS is removed from the stack.

   If the stack represents an exception, *and* the function call returns
   a 'true' value, this information is "zapped" and replaced with a single
   ``WHY_SILENCED`` to prevent ``END_FINALLY`` from re-raising the exception.
   (But non-local gotos will still be resumed.)

   .. XXX explain the WHY stuff!


.. opcode:: STORE_LOCALS

   Pops TOS from the stack and stores it as the current frame's ``f_locals``.
   This is used in class construction.


All of the following opcodes expect arguments.  An argument is two bytes, with
the more significant byte last.

.. opcode:: STORE_NAME (namei)

   Implements ``name = TOS``. *namei* is the index of *name* in the attribute
   :attr:`co_names` of the code object. The compiler tries to use ``STORE_FAST``
   or ``STORE_GLOBAL`` if possible.


.. opcode:: DELETE_NAME (namei)

   Implements ``del name``, where *namei* is the index into :attr:`co_names`
   attribute of the code object.


.. opcode:: UNPACK_SEQUENCE (count)

   Unpacks TOS into *count* individual values, which are put onto the stack
   right-to-left.


.. opcode:: UNPACK_EX (counts)

   Implements assignment with a starred target: Unpacks an iterable in TOS into
   individual values, where the total number of values can be smaller than the
   number of items in the iterable: one the new values will be a list of all
   leftover items.

   The low byte of *counts* is the number of values before the list value, the
   high byte of *counts* the number of values after it.  The resulting values
   are put onto the stack right-to-left.


.. opcode:: STORE_ATTR (namei)

   Implements ``TOS.name = TOS1``, where *namei* is the index of name in
   :attr:`co_names`.


.. opcode:: DELETE_ATTR (namei)

   Implements ``del TOS.name``, using *namei* as index into :attr:`co_names`.


.. opcode:: STORE_GLOBAL (namei)

   Works as ``STORE_NAME``, but stores the name as a global.


.. opcode:: DELETE_GLOBAL (namei)

   Works as ``DELETE_NAME``, but deletes a global name.


.. opcode:: LOAD_CONST (consti)

   Pushes ``co_consts[consti]`` onto the stack.


.. opcode:: LOAD_NAME (namei)

   Pushes the value associated with ``co_names[namei]`` onto the stack.


.. opcode:: BUILD_TUPLE (count)

   Creates a tuple consuming *count* items from the stack, and pushes the resulting
   tuple onto the stack.


.. opcode:: BUILD_LIST (count)

   Works as ``BUILD_TUPLE``, but creates a list.


.. opcode:: BUILD_SET (count)

   Works as ``BUILD_TUPLE``, but creates a set.


.. opcode:: BUILD_MAP (count)

   Pushes a new dictionary object onto the stack.  The dictionary is pre-sized
   to hold *count* entries.


.. opcode:: LOAD_ATTR (namei)

   Replaces TOS with ``getattr(TOS, co_names[namei])``.


.. opcode:: COMPARE_OP (opname)

   Performs a Boolean operation.  The operation name can be found in
   ``cmp_op[opname]``.


.. opcode:: IMPORT_NAME (namei)

   Imports the module ``co_names[namei]``.  TOS and TOS1 are popped and provide
   the *fromlist* and *level* arguments of :func:`__import__`.  The module
   object is pushed onto the stack.  The current namespace is not affected:
   for a proper import statement, a subsequent ``STORE_FAST`` instruction
   modifies the namespace.


.. opcode:: IMPORT_FROM (namei)

   Loads the attribute ``co_names[namei]`` from the module found in TOS. The
   resulting object is pushed onto the stack, to be subsequently stored by a
   ``STORE_FAST`` instruction.


.. opcode:: JUMP_FORWARD (delta)

   Increments bytecode counter by *delta*.


.. opcode:: POP_JUMP_IF_TRUE (target)

   If TOS is true, sets the bytecode counter to *target*.  TOS is popped.


.. opcode:: POP_JUMP_IF_FALSE (target)

   If TOS is false, sets the bytecode counter to *target*.  TOS is popped.


.. opcode:: JUMP_IF_TRUE_OR_POP (target)

   If TOS is true, sets the bytecode counter to *target* and leaves TOS
   on the stack.  Otherwise (TOS is false), TOS is popped.


.. opcode:: JUMP_IF_FALSE_OR_POP (target)

   If TOS is false, sets the bytecode counter to *target* and leaves
   TOS on the stack.  Otherwise (TOS is true), TOS is popped.


.. opcode:: JUMP_ABSOLUTE (target)

   Set bytecode counter to *target*.


.. opcode:: FOR_ITER (delta)

   ``TOS`` is an :term:`iterator`.  Call its :meth:`__next__` method.  If this
   yields a new value, push it on the stack (leaving the iterator below it).  If
   the iterator indicates it is exhausted ``TOS`` is popped, and the byte code
   counter is incremented by *delta*.


.. opcode:: LOAD_GLOBAL (namei)

   Loads the global named ``co_names[namei]`` onto the stack.


.. opcode:: SETUP_LOOP (delta)

   Pushes a block for a loop onto the block stack.  The block spans from the
   current instruction with a size of *delta* bytes.


.. opcode:: SETUP_EXCEPT (delta)

   Pushes a try block from a try-except clause onto the block stack. *delta* points
   to the first except block.


.. opcode:: SETUP_FINALLY (delta)

   Pushes a try block from a try-except clause onto the block stack. *delta* points
   to the finally block.

.. opcode:: STORE_MAP

   Store a key and value pair in a dictionary.  Pops the key and value while leaving
   the dictionary on the stack.

.. opcode:: LOAD_FAST (var_num)

   Pushes a reference to the local ``co_varnames[var_num]`` onto the stack.


.. opcode:: STORE_FAST (var_num)

   Stores TOS into the local ``co_varnames[var_num]``.


.. opcode:: DELETE_FAST (var_num)

   Deletes local ``co_varnames[var_num]``.


.. opcode:: LOAD_CLOSURE (i)

   Pushes a reference to the cell contained in slot *i* of the cell and free
   variable storage.  The name of the variable is  ``co_cellvars[i]`` if *i* is
   less than the length of *co_cellvars*.  Otherwise it is  ``co_freevars[i -
   len(co_cellvars)]``.


.. opcode:: LOAD_DEREF (i)

   Loads the cell contained in slot *i* of the cell and free variable storage.
   Pushes a reference to the object the cell contains on the stack.


.. opcode:: STORE_DEREF (i)

   Stores TOS into the cell contained in slot *i* of the cell and free variable
   storage.


.. opcode:: DELETE_DEREF (i)

   Empties the cell contained in slot *i* of the cell and free variable storage.
   Used by the :keyword:`del` statement.


.. opcode:: RAISE_VARARGS (argc)

   Raises an exception. *argc* indicates the number of parameters to the raise
   statement, ranging from 0 to 3.  The handler will find the traceback as TOS2,
   the parameter as TOS1, and the exception as TOS.


.. opcode:: CALL_FUNCTION (argc)

   Calls a function.  The low byte of *argc* indicates the number of positional
   parameters, the high byte the number of keyword parameters. On the stack, the
   opcode finds the keyword parameters first.  For each keyword argument, the value
   is on top of the key.  Below the keyword parameters, the positional parameters
   are on the stack, with the right-most parameter on top.  Below the parameters,
   the function object to call is on the stack.  Pops all function arguments, and
   the function itself off the stack, and pushes the return value.


.. opcode:: MAKE_FUNCTION (argc)

   Pushes a new function object on the stack.  TOS is the code associated with the
   function.  The function object is defined to have *argc* default parameters,
   which are found below TOS.


.. opcode:: MAKE_CLOSURE (argc)

   Creates a new function object, sets its *__closure__* slot, and pushes it on
   the stack.  TOS is the code associated with the function, TOS1 the tuple
   containing cells for the closure's free variables.  The function also has
   *argc* default parameters, which are found below the cells.


.. opcode:: BUILD_SLICE (argc)

   .. index:: builtin: slice

   Pushes a slice object on the stack.  *argc* must be 2 or 3.  If it is 2,
   ``slice(TOS1, TOS)`` is pushed; if it is 3, ``slice(TOS2, TOS1, TOS)`` is
   pushed. See the :func:`slice` built-in function for more information.


.. opcode:: EXTENDED_ARG (ext)

   Prefixes any opcode which has an argument too big to fit into the default two
   bytes.  *ext* holds two additional bytes which, taken together with the
   subsequent opcode's argument, comprise a four-byte argument, *ext* being the two
   most-significant bytes.


.. opcode:: CALL_FUNCTION_VAR (argc)

   Calls a function. *argc* is interpreted as in ``CALL_FUNCTION``. The top element
   on the stack contains the variable argument list, followed by keyword and
   positional arguments.


.. opcode:: CALL_FUNCTION_KW (argc)

   Calls a function. *argc* is interpreted as in ``CALL_FUNCTION``. The top element
   on the stack contains the keyword arguments dictionary,  followed by explicit
   keyword and positional arguments.


.. opcode:: CALL_FUNCTION_VAR_KW (argc)

   Calls a function. *argc* is interpreted as in ``CALL_FUNCTION``.  The top
   element on the stack contains the keyword arguments dictionary, followed by the
   variable-arguments tuple, followed by explicit keyword and positional arguments.


.. opcode:: HAVE_ARGUMENT

   This is not really an opcode.  It identifies the dividing line between opcodes
   which don't take arguments ``< HAVE_ARGUMENT`` and those which do ``>=
   HAVE_ARGUMENT``.