dis --- Python バイトコードの逆アセンブラ

ソースコード: Lib/dis.py


dis モジュールは CPython バイトコード を逆アセンブルすることでバイトコードの解析をサポートします。このモジュールが入力として受け取る CPython バイトコードはファイル Include/opcode.h に定義されており、 コンパイラとインタプリタが使用しています。

CPython 実装の詳細: バイトコードは CPython インタプリタの実装詳細です。Python のバージョン間でバイトコードの追加や、削除、変更がないという保証はありません。このモジュールを使用することによって Python の異なる VM または異なるリリースの間で動作すると考えるべきではありません。

バージョン 3.6 で変更: 従来は使用されるバイト数は命令ごとに異なりましたが、このモジュールでは各々一つの命令につき2バイト使用することとなっています。

バージョン 3.10 で変更: The argument of jump, exception handling and loop instructions is now the instruction offset rather than the byte offset.

バージョン 3.11 で変更: Some instructions are accompanied by one or more inline cache entries, which take the form of CACHE instructions. These instructions are hidden by default, but can be shown by passing show_caches=True to any dis utility. Furthermore, the interpreter now adapts the bytecode to specialize it for different runtime conditions. The adaptive bytecode can be shown by passing adaptive=True.

バージョン 3.12 で変更: The argument of a jump is the offset of the target instruction relative to the instruction that appears immediately after the jump instruction's CACHE entries.

As a consequence, the presence of the CACHE instructions is transparent for forward jumps but needs to be taken into account when reasoning about backward jumps.

Example: Given the function myfunc():

def myfunc(alist):
    return len(alist)

the following command can be used to display the disassembly of myfunc():

>>> dis.dis(myfunc)
  2           0 RESUME                   0

  3           2 LOAD_GLOBAL              1 (NULL + len)
             12 LOAD_FAST                0 (alist)
             14 CALL                     1
             22 RETURN_VALUE

("2" は行番号です)。

コマンドライン・インターフェース

The dis module can be invoked as a script from the command line:

python -m dis [-h] [infile]

以下のオプションが使用できます:

-h, --help

使い方を表示して終了します。

If infile is specified, its disassembled code will be written to stdout. Otherwise, disassembly is performed on compiled source code recieved from stdin.

バイトコード解析

バージョン 3.4 で追加.

バイトコード解析の API を使うと、 Python のコード片を Bytecode オブジェクトでラップでき、コンパイルされたコードの細かいところに簡単にアクセスできます。

class dis.Bytecode(x, *, first_line=None, current_offset=None, show_caches=False, adaptive=False)

関数、ジェネレータ、非同期ジェネレータ、コルーチン、メソッド、ソースコード文字列、(compile() が返すような) コードオブジェクトに対応するバイトコードを解析します。

これは、下で並べられている関数の多くのものをまとめた便利なラッパーです。 とりわけ目立つのは get_instructions() で、 Bytecode インスタンスに対し反復処理をしながら、バイトコード命令を Instruction インスタンスとして返します。

first_lineNone でない場合は、それを逆アセンブルしたコードのソースの最初の行に表示する行番号とします。 そうでない場合は、ソースの行の情報 (もしあれば) を逆アセンブルされたコードオブジェクトから直接取得します。

current_offsetNone でない場合は、逆アセンブルされたコードでのあるインストラクションのオフセット位置を示します。 これを設定すると、 dis() の出力において、指定された命令コード (opcode) に "現在の命令 (instruction)" を表す印が表示されます。

If show_caches is True, dis() will display inline cache entries used by the interpreter to specialize the bytecode.

If adaptive is True, dis() will display specialized bytecode that may be different from the original bytecode.

classmethod from_traceback(tb, *, show_caches=False)

与えられたトレースバックから Bytecode インスタンスを構築し、 current_offset がその例外の原因となった命令となるよう設定します。

codeobj

コンパイルされたコードオブジェクト。

first_line

コードオブジェクトのソースの最初の行 (利用可能であれば)

dis()

バイトコード命令の整形された表示を返します (dis.dis() と同じ出力になりますが、複数行文字列として返されます)。

info()

code_info() のようなコードオブジェクトの詳細を含んだ整形された複数行文字列を返します。

バージョン 3.7 で変更: This can now handle coroutine and asynchronous generator objects.

バージョン 3.11 で変更: Added the show_caches and adaptive parameters.

例:

>>> bytecode = dis.Bytecode(myfunc)
>>> for instr in bytecode:
...     print(instr.opname)
...
RESUME
LOAD_GLOBAL
LOAD_FAST
CALL
RETURN_VALUE

解析関数

dis モジュールには、以下に挙げる入力を直接欲しい出力に変換する解析関数も定義してあります。 1つの命令だけが実行されている場合は、解析オブジェクトをいったん作るよりはこちらの方が便利です:

dis.code_info(x)

渡された関数、ジェネレータ、非同期ジェネレータ、コルーチン、メソッド、ソースコード文字列、コードオブジェクトに対する、詳細なコードオブジェクトの情報を、整形された複数行の文字列として返します。

この結果は実装に強く依存しており、Python VM や Python のバージョンによって異なることがあります。

バージョン 3.2 で追加.

バージョン 3.7 で変更: This can now handle coroutine and asynchronous generator objects.

dis.show_code(x, *, file=None)

渡された関数、メソッド、ソースコード文字列、コードオブジェクトに対する、詳細なコードオブジェクトの情報を、file (または file が指定されていなければ sys.stdout) に表示します。

これは、インタラクティブシェル上で使うことを想定した、print(code_info(x), file=file) の便利なショートカットです。

バージョン 3.2 で追加.

バージョン 3.4 で変更: file 引数が追加されました。

dis.dis(x=None, *, file=None, depth=None, show_caches=False, adaptive=False)

Disassemble the x object. x can denote either a module, a class, a method, a function, a generator, an asynchronous generator, a coroutine, 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 (including class and static methods). For a code object or sequence of raw bytecode, it prints one line per bytecode instruction. It also recursively disassembles nested code objects. These can include generator expressions, nested functions, the bodies of nested classes, and the code objects used for annotation scopes. Strings are first compiled to code objects with the compile() built-in function before being disassembled. If no object is provided, this function disassembles the last traceback.

file 引数が渡された場合は、アセンブリをそこに書き込みます。 そうでない場合は sys.stdout に出力します。

The maximal depth of recursion is limited by depth unless it is None. depth=0 means no recursion.

If show_caches is True, this function will display inline cache entries used by the interpreter to specialize the bytecode.

If adaptive is True, this function will display specialized bytecode that may be different from the original bytecode.

バージョン 3.4 で変更: file 引数が追加されました。

バージョン 3.7 で変更: Implemented recursive disassembling and added depth parameter.

バージョン 3.7 で変更: This can now handle coroutine and asynchronous generator objects.

バージョン 3.11 で変更: Added the show_caches and adaptive parameters.

dis.distb(tb=None, *, file=None, show_caches=False, adaptive=False)

トレースバックのスタックの先頭の関数を逆アセンブルします。Noneが渡された場合は最後のトレースバックを使います。例外を引き起こした命令が表示されます。

file 引数が渡された場合は、アセンブリをそこに書き込みます。 そうでない場合は sys.stdout に出力します。

バージョン 3.4 で変更: file 引数が追加されました。

バージョン 3.11 で変更: Added the show_caches and adaptive parameters.

dis.disassemble(code, lasti=-1, *, file=None, show_caches=False, adaptive=False)
dis.disco(code, lasti=-1, *, file=None, show_caches=False, adaptive=False)

コードオブジェクトを逆アセンブルします。lasti が与えられた場合は、最後の命令を示します。出力は次のようなカラムに分割されます:

  1. 各行の最初の命令に対する行番号。

  2. 現在の命令。 --> として示されます。

  3. ラベル付けされた命令。 >> とともに表示されます。

  4. 命令のアドレス。

  5. 命令コード名。

  6. 命令パラメタ。

  7. パラメタの解釈を括弧で囲んだもの。

パラメタの解釈は、ローカル変数とグローバル変数の名前、定数の値、 分岐先、比較命令を認識します。

file 引数が渡された場合は、アセンブリをそこに書き込みます。 そうでない場合は sys.stdout に出力します。

バージョン 3.4 で変更: file 引数が追加されました。

バージョン 3.11 で変更: Added the show_caches and adaptive parameters.

dis.get_instructions(x, *, first_line=None, show_caches=False, adaptive=False)

渡された関数、メソッド、ソースコード文字列、コードオブジェクトにある命令のイテレータを返します。

イテレータは、与えられたコードの各命令の詳細情報を保持する名前付きタプル Instruction からなる列を生成します。

first_lineNone でない場合は、それを逆アセンブルしたコードのソースの最初の行に表示する行番号とします。 そうでない場合は、ソースの行の情報 (もしあれば) を逆アセンブルされたコードオブジェクトから直接取得します。

The show_caches and adaptive parameters work as they do in dis().

バージョン 3.4 で追加.

バージョン 3.11 で変更: Added the show_caches and adaptive parameters.

dis.findlinestarts(code)

This generator function uses the co_lines() method 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.

バージョン 3.6 で変更: Line numbers can be decreasing. Before, they were always increasing.

バージョン 3.10 で変更: The PEP 626 co_lines() method is used instead of the co_firstlineno and co_lnotab attributes of the code object.

dis.findlabels(code)

Detect all offsets in the raw compiled bytecode string code which are jump targets, and return a list of these offsets.

dis.stack_effect(opcode, oparg=None, *, jump=None)

opcode と引数 oparg がスタックに与える影響を計算します。

If the code has a jump target and jump is True, stack_effect() will return the stack effect of jumping. If jump is False, it will return the stack effect of not jumping. And if jump is None (default), it will return the maximal stack effect of both cases.

バージョン 3.4 で追加.

バージョン 3.8 で変更: Added jump parameter.

Python バイトコード命令

get_instructions() 関数と Bytecode クラスはバイトコード命令の詳細を Instruction インスタンスの形で提供します:

class dis.Instruction

バイトコード命令の詳細

opcode

以下の命令コードの値と 命令コードコレクション のバイトコードの値に対応する、命令の数値コードです。

opname

人間が読むための命令名

arg

(ある場合は) 命令の数値引数、無ければ None

argval

resolved arg value (if any), otherwise None

argrepr

human readable description of operation argument (if any), otherwise an empty string.

offset

バイトコード列の中での命令の開始位置

starts_line

(ある場合は) この命令コードが始まる行、無ければ None

is_jump_target

他のコードからここへジャンプする場合は True 、そうでない場合は False

positions

dis.Positions object holding the start and end locations that are covered by this instruction.

バージョン 3.4 で追加.

バージョン 3.11 で変更: Field positions is added.

class dis.Positions

In case the information is not available, some fields might be None.

lineno
end_lineno
col_offset
end_col_offset

バージョン 3.11 で追加.

現在 Python コンパイラは次のバイトコード命令を生成します。

一般的な命令

In the following, We will refer to the interpreter stack as STACK and describe operations on it as if it was a Python list. The top of the stack corresponds to STACK[-1] in this language.

NOP

Do nothing code. Used as a placeholder by the bytecode optimizer, and to generate line tracing events.

POP_TOP

Removes the top-of-stack item:

STACK.pop()
END_FOR

Removes the top two values from the stack. Equivalent to POP_TOP; POP_TOP. Used to clean up at the end of loops, hence the name.

バージョン 3.12 で追加.

END_SEND

Implements del STACK[-2]. Used to clean up when a generator exits.

バージョン 3.12 で追加.

COPY(i)

Push the i-th item to the top of the stack without removing it from its original location:

assert i > 0
STACK.append(STACK[-i])

バージョン 3.11 で追加.

SWAP(i)

Swap the top of the stack with the i-th element:

STACK[-i], STACK[-1] = STACK[-1], STACK[-i]

バージョン 3.11 で追加.

CACHE

Rather than being an actual instruction, this opcode is used to mark extra space for the interpreter to cache useful data directly in the bytecode itself. It is automatically hidden by all dis utilities, but can be viewed with show_caches=True.

Logically, this space is part of the preceding instruction. Many opcodes expect to be followed by an exact number of caches, and will instruct the interpreter to skip over them at runtime.

Populated caches can look like arbitrary instructions, so great care should be taken when reading or modifying raw, adaptive bytecode containing quickened data.

バージョン 3.11 で追加.

1オペランド命令

1オペランド命令はスタックの先頭を取り出して操作を適用し、結果をスタックへプッシュし戻します。

UNARY_NEGATIVE

Implements STACK[-1] = -STACK[-1].

UNARY_NOT

Implements STACK[-1] = not STACK[-1].

UNARY_INVERT

Implements STACK[-1] = ~STACK[-1].

GET_ITER

Implements STACK[-1] = iter(STACK[-1]).

GET_YIELD_FROM_ITER

If STACK[-1] is a generator iterator or coroutine object it is left as is. Otherwise, implements STACK[-1] = iter(STACK[-1]).

バージョン 3.5 で追加.

Binary and in-place operations

Binary operations remove the top two items from the stack (STACK[-1] and STACK[-2]). They perform the operation, then put the result back on the stack.

In-place operations are like binary operations, but the operation is done in-place when STACK[-2] supports it, and the resulting STACK[-1] may be (but does not have to be) the original STACK[-2].

BINARY_OP(op)

Implements the binary and in-place operators (depending on the value of op):

rhs = STACK.pop()
lhs = STACK.pop()
STACK.append(lhs op rhs)

バージョン 3.11 で追加.

BINARY_SUBSCR

Implements:

key = STACK.pop()
container = STACK.pop()
STACK.append(container[key])
STORE_SUBSCR

Implements:

key = STACK.pop()
container = STACK.pop()
value = STACK.pop()
container[key] = value
DELETE_SUBSCR

Implements:

key = STACK.pop()
container = STACK.pop()
del container[key]
BINARY_SLICE

Implements:

end = STACK.pop()
start = STACK.pop()
container = STACK.pop()
STACK.append(container[start:end])

バージョン 3.12 で追加.

STORE_SLICE

Implements:

end = STACK.pop()
start = STACK.pop()
container = STACK.pop()
values = STACK.pop()
container[start:end] = value

バージョン 3.12 で追加.

コルーチン命令コード

GET_AWAITABLE(where)

Implements STACK[-1] = get_awaitable(STACK[-1]), where get_awaitable(o) returns o if o is a coroutine object or a generator object with the CO_ITERABLE_COROUTINE flag, or resolves o.__await__.

If the where operand is nonzero, it indicates where the instruction occurs:

  • 1: After a call to __aenter__

  • 2: After a call to __aexit__

バージョン 3.5 で追加.

バージョン 3.11 で変更: Previously, this instruction did not have an oparg.

GET_AITER

Implements STACK[-1] = STACK[-1].__aiter__().

バージョン 3.5 で追加.

バージョン 3.7 で変更: Returning awaitable objects from __aiter__ is no longer supported.

GET_ANEXT

Implement STACK.append(get_awaitable(STACK[-1].__anext__())) to the stack. See GET_AWAITABLE for details about get_awaitable.

バージョン 3.5 で追加.

END_ASYNC_FOR

Terminates an async for loop. Handles an exception raised when awaiting a next item. The stack contains the async iterable in STACK[-2] and the raised exception in STACK[-1]. Both are popped. If the exception is not StopAsyncIteration, it is re-raised.

バージョン 3.8 で追加.

バージョン 3.11 で変更: Exception representation on the stack now consist of one, not three, items.

CLEANUP_THROW

Handles an exception raised during a throw() or close() call through the current frame. If STACK[-1] is an instance of StopIteration, pop three values from the stack and push its value member. Otherwise, re-raise STACK[-1].

バージョン 3.12 で追加.

BEFORE_ASYNC_WITH

Resolves __aenter__ and __aexit__ from STACK[-1]. Pushes __aexit__ and result of __aenter__() to the stack:

STACK.extend((__aexit__, __aenter__())

バージョン 3.5 で追加.

その他の命令コード

SET_ADD(i)

Implements:

item = STACK.pop()
set.add(STACK[-i], item)

Used to implement set comprehensions.

LIST_APPEND(i)

Implements:

item = STACK.pop()
list.append(STACK[-i], item)

Used to implement list comprehensions.

MAP_ADD(i)

Implements:

value = STACK.pop()
key = STACK.pop()
dict.__setitem__(STACK[-i], key, value)

Used to implement dict comprehensions.

バージョン 3.1 で追加.

バージョン 3.8 で変更: Map value is STACK[-1] and map key is STACK[-2]. Before, those were reversed.

SET_ADD, LIST_APPEND, MAP_ADD は、追加した値または key/value ペアをスタックから取り除きますが、コンテナオブジェクトはループの次のイテレーションで利用できるようにスタックに残しておきます。

RETURN_VALUE

Returns with STACK[-1] to the caller of the function.

RETURN_CONST(consti)

Returns with co_consts[consti] to the caller of the function.

バージョン 3.12 で追加.

YIELD_VALUE

Yields STACK.pop() from a generator.

バージョン 3.11 で変更: oparg set to be the stack depth.

バージョン 3.12 で変更: oparg set to be the exception block depth, for efficient closing of generators.

SETUP_ANNOTATIONS

Checks whether __annotations__ is defined in locals(), if not it is set up to an empty dict. This opcode is only emitted if a class or module body contains variable annotations statically.

バージョン 3.6 で追加.

POP_EXCEPT

Pops a value from the stack, which is used to restore the exception state.

バージョン 3.11 で変更: Exception representation on the stack now consist of one, not three, items.

RERAISE

Re-raises the exception currently on top of the stack. If oparg is non-zero, pops an additional value from the stack which is used to set f_lasti of the current frame.

バージョン 3.9 で追加.

バージョン 3.11 で変更: Exception representation on the stack now consist of one, not three, items.

PUSH_EXC_INFO

Pops a value from the stack. Pushes the current exception to the top of the stack. Pushes the value originally popped back to the stack. Used in exception handlers.

バージョン 3.11 で追加.

CHECK_EXC_MATCH

Performs exception matching for except. Tests whether the STACK[-2] is an exception matching STACK[-1]. Pops STACK[-1] and pushes the boolean result of the test.

バージョン 3.11 で追加.

CHECK_EG_MATCH

Performs exception matching for except*. Applies split(STACK[-1]) on the exception group representing STACK[-2].

In case of a match, pops two items from the stack and pushes the non-matching subgroup (None in case of full match) followed by the matching subgroup. When there is no match, pops one item (the match type) and pushes None.

バージョン 3.11 で追加.

WITH_EXCEPT_START

Calls the function in position 4 on the stack with arguments (type, val, tb) representing the exception at the top of the stack. Used to implement the call context_manager.__exit__(*exc_info()) when an exception has occurred in a with statement.

バージョン 3.9 で追加.

バージョン 3.11 で変更: The __exit__ function is in position 4 of the stack rather than 7. Exception representation on the stack now consist of one, not three, items.

LOAD_ASSERTION_ERROR

Pushes AssertionError onto the stack. Used by the assert statement.

バージョン 3.9 で追加.

LOAD_BUILD_CLASS

Pushes builtins.__build_class__() onto the stack. It is later called to construct a class.

BEFORE_WITH

This opcode performs several operations before a with block starts. First, it loads __exit__() from the context manager and pushes it onto the stack for later use by WITH_EXCEPT_START. Then, __enter__() is called. Finally, the result of calling the __enter__() method is pushed onto the stack.

バージョン 3.11 で追加.

GET_LEN

Perform STACK.append(len(STACK[-1])).

バージョン 3.10 で追加.

MATCH_MAPPING

If STACK[-1] is an instance of collections.abc.Mapping (or, more technically: if it has the Py_TPFLAGS_MAPPING flag set in its tp_flags), push True onto the stack. Otherwise, push False.

バージョン 3.10 で追加.

MATCH_SEQUENCE

If STACK[-1] is an instance of collections.abc.Sequence and is not an instance of str/bytes/bytearray (or, more technically: if it has the Py_TPFLAGS_SEQUENCE flag set in its tp_flags), push True onto the stack. Otherwise, push False.

バージョン 3.10 で追加.

MATCH_KEYS

STACK[-1] is a tuple of mapping keys, and STACK[-2] is the match subject. If STACK[-2] contains all of the keys in STACK[-1], push a tuple containing the corresponding values. Otherwise, push None.

バージョン 3.10 で追加.

バージョン 3.11 で変更: Previously, this instruction also pushed a boolean value indicating success (True) or failure (False).

STORE_NAME(namei)

Implements name = STACK.pop(). namei is the index of name in the attribute co_names of the code object. The compiler tries to use STORE_FAST or STORE_GLOBAL if possible.

DELETE_NAME(namei)

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

UNPACK_SEQUENCE(count)

Unpacks STACK[-1] into count individual values, which are put onto the stack right-to-left. Require there to be exactly count values.:

assert(len(STACK[-1]) == count)
STACK.extend(STACK.pop()[:-count-1:-1])
UNPACK_EX(counts)

Implements assignment with a starred target: Unpacks an iterable in STACK[-1] into individual values, where the total number of values can be smaller than the number of items in the iterable: one of the new values will be a list of all leftover items.

The number of values before and after the list value is limited to 255.

The number of values before the list value is encoded in the argument of the opcode. The number of values after the list if any is encoded using an EXTENDED_ARG. As a consequence, the argument can be seen as a two bytes values where 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 extracted values are put onto the stack right-to-left, i.e. a, *b, c = d will be stored after execution as STACK.extend((a, b, c)).

STORE_ATTR(namei)

Implements:

obj = STACK.pop()
value = STACK.pop()
obj.name = value

where namei is the index of name in co_names of the code object.

DELETE_ATTR(namei)

Implements:

obj = STACK.pop()
del obj.name

where namei is the index of name into co_names of the code object.

STORE_GLOBAL(namei)

STORE_NAME と同じように動作しますが、 name をグローバルとして保存します。

DELETE_GLOBAL(namei)

DELETE_NAME と同じように動作しますが、グローバルの name を削除します。

LOAD_CONST(consti)

co_consts[consti] をスタックにプッシュします。

LOAD_NAME(namei)

Pushes the value associated with co_names[namei] onto the stack. The name is looked up within the locals, then the globals, then the builtins.

LOAD_LOCALS

Pushes a reference to the locals dictionary onto the stack. This is used to prepare namespace dictionaries for LOAD_FROM_DICT_OR_DEREF and LOAD_FROM_DICT_OR_GLOBALS.

バージョン 3.12 で追加.

LOAD_FROM_DICT_OR_GLOBALS(i)

Pops a mapping off the stack and looks up the value for co_names[namei]. If the name is not found there, looks it up in the globals and then the builtins, similar to LOAD_GLOBAL. This is used for loading global variables in annotation scopes within class bodies.

バージョン 3.12 で追加.

BUILD_TUPLE(count)

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

assert count > 0
STACK, values = STACK[:-count], STACK[-count:]
STACK.append(tuple(values))
BUILD_LIST(count)

BUILD_TUPLE と同じように動作しますが、この命令はリストを作り出します。

BUILD_SET(count)

BUILD_TUPLE と同じように動作しますが、この命令は set を作り出します。

BUILD_MAP(count)

Pushes a new dictionary object onto the stack. Pops 2 * count items so that the dictionary holds count entries: {..., STACK[-4]: STACK[-3], STACK[-2]: STACK[-1]}.

バージョン 3.5 で変更: The dictionary is created from stack items instead of creating an empty dictionary pre-sized to hold count items.

BUILD_CONST_KEY_MAP(count)

The version of BUILD_MAP specialized for constant keys. Pops the top element on the stack which contains a tuple of keys, then starting from STACK[-2], pops count values to form values in the built dictionary.

バージョン 3.6 で追加.

BUILD_STRING(count)

Concatenates count strings from the stack and pushes the resulting string onto the stack.

バージョン 3.6 で追加.

LIST_EXTEND(i)

Implements:

seq = STACK.pop()
list.extend(STACK[-i], seq)

Used to build lists.

バージョン 3.9 で追加.

SET_UPDATE(i)

Implements:

seq = STACK.pop()
set.update(STACK[-i], seq)

Used to build sets.

バージョン 3.9 で追加.

DICT_UPDATE(i)

Implements:

map = STACK.pop()
dict.update(STACK[-i], map)

Used to build dicts.

バージョン 3.9 で追加.

DICT_MERGE(i)

Like DICT_UPDATE but raises an exception for duplicate keys.

バージョン 3.9 で追加.

LOAD_ATTR(namei)

If the low bit of namei is not set, this replaces STACK[-1] with getattr(STACK[-1], co_names[namei>>1]).

If the low bit of namei is set, this will attempt to load a method named co_names[namei>>1] from the STACK[-1] object. STACK[-1] is popped. This bytecode distinguishes two cases: if STACK[-1] has a method with the correct name, the bytecode pushes the unbound method and STACK[-1]. STACK[-1] will be used as the first argument (self) by CALL when calling the unbound method. Otherwise, NULL and the object returned by the attribute lookup are pushed.

バージョン 3.12 で変更: If the low bit of namei is set, then a NULL or self is pushed to the stack before the attribute or unbound method respectively.

LOAD_SUPER_ATTR(namei)

This opcode implements super(), both in its zero-argument and two-argument forms (e.g. super().method(), super().attr and super(cls, self).method(), super(cls, self).attr).

It pops three values from the stack (from top of stack down): - self: the first argument to the current method - cls: the class within which the current method was defined - the global super

With respect to its argument, it works similarly to LOAD_ATTR, except that namei is shifted left by 2 bits instead of 1.

The low bit of namei signals to attempt a method load, as with LOAD_ATTR, which results in pushing None and the loaded method. When it is unset a single value is pushed to the stack.

The second-low bit of namei, if set, means that this was a two-argument call to super() (unset means zero-argument).

バージョン 3.12 で追加.

COMPARE_OP(opname)

ブール命令を実行します。命令名は cmp_op[opname] にあります。

IS_OP(invert)

Performs is comparison, or is not if invert is 1.

バージョン 3.9 で追加.

CONTAINS_OP(invert)

Performs in comparison, or not in if invert is 1.

バージョン 3.9 で追加.

IMPORT_NAME(namei)

Imports the module co_names[namei]. STACK[-1] and STACK[-2] are popped and provide the fromlist and level arguments of __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.

IMPORT_FROM(namei)

Loads the attribute co_names[namei] from the module found in STACK[-1]. The resulting object is pushed onto the stack, to be subsequently stored by a STORE_FAST instruction.

JUMP_FORWARD(delta)

バイトコードカウンタを delta だけ増加させます。

JUMP_BACKWARD(delta)

Decrements bytecode counter by delta. Checks for interrupts.

バージョン 3.11 で追加.

JUMP_BACKWARD_NO_INTERRUPT(delta)

Decrements bytecode counter by delta. Does not check for interrupts.

バージョン 3.11 で追加.

POP_JUMP_IF_TRUE(delta)

If STACK[-1] is true, increments the bytecode counter by delta. STACK[-1] is popped.

バージョン 3.11 で変更: The oparg is now a relative delta rather than an absolute target. This opcode is a pseudo-instruction, replaced in final bytecode by the directed versions (forward/backward).

バージョン 3.12 で変更: This is no longer a pseudo-instruction.

POP_JUMP_IF_FALSE(delta)

If STACK[-1] is false, increments the bytecode counter by delta. STACK[-1] is popped.

バージョン 3.11 で変更: The oparg is now a relative delta rather than an absolute target. This opcode is a pseudo-instruction, replaced in final bytecode by the directed versions (forward/backward).

バージョン 3.12 で変更: This is no longer a pseudo-instruction.

POP_JUMP_IF_NOT_NONE(delta)

If STACK[-1] is not None, increments the bytecode counter by delta. STACK[-1] is popped.

This opcode is a pseudo-instruction, replaced in final bytecode by the directed versions (forward/backward).

バージョン 3.11 で追加.

バージョン 3.12 で変更: This is no longer a pseudo-instruction.

POP_JUMP_IF_NONE(delta)

If STACK[-1] is None, increments the bytecode counter by delta. STACK[-1] is popped.

This opcode is a pseudo-instruction, replaced in final bytecode by the directed versions (forward/backward).

バージョン 3.11 で追加.

バージョン 3.12 で変更: This is no longer a pseudo-instruction.

FOR_ITER(delta)

STACK[-1] is an iterator. Call its __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 then the byte code counter is incremented by delta.

バージョン 3.12 で変更: Up until 3.11 the iterator was popped when it was exhausted.

LOAD_GLOBAL(namei)

co_names[namei>>1] という名前のグローバルをスタック上にロードします。

バージョン 3.11 で変更: If the low bit of namei is set, then a NULL is pushed to the stack before the global variable.

LOAD_FAST(var_num)

ローカルな co_varnames[var_num] への参照をスタックにプッシュします。

バージョン 3.12 で変更: This opcode is now only used in situations where the local variable is guaranteed to be initialized. It cannot raise UnboundLocalError.

LOAD_FAST_CHECK(var_num)

Pushes a reference to the local co_varnames[var_num] onto the stack, raising an UnboundLocalError if the local variable has not been initialized.

バージョン 3.12 で追加.

LOAD_FAST_AND_CLEAR(var_num)

Pushes a reference to the local co_varnames[var_num] onto the stack (or pushes NULL onto the stack if the local variable has not been initialized) and sets co_varnames[var_num] to NULL.

バージョン 3.12 で追加.

STORE_FAST(var_num)

Stores STACK.pop() into the local co_varnames[var_num].

DELETE_FAST(var_num)

ローカルな co_varnames[var_num] を削除します。

MAKE_CELL(i)

Creates a new cell in slot i. If that slot is nonempty then that value is stored into the new cell.

バージョン 3.11 で追加.

LOAD_CLOSURE(i)

Pushes a reference to the cell contained in slot i of the "fast locals" storage. The name of the variable is co_fastlocalnames[i].

Note that LOAD_CLOSURE is effectively an alias for LOAD_FAST. It exists to keep bytecode a little more readable.

バージョン 3.11 で変更: i is no longer offset by the length of co_varnames.

LOAD_DEREF(i)

Loads the cell contained in slot i of the "fast locals" storage. Pushes a reference to the object the cell contains on the stack.

バージョン 3.11 で変更: i is no longer offset by the length of co_varnames.

LOAD_FROM_DICT_OR_DEREF(i)

Pops a mapping off the stack and looks up the name associated with slot i of the "fast locals" storage in this mapping. If the name is not found there, loads it from the cell contained in slot i, similar to LOAD_DEREF. This is used for loading free variables in class bodies (which previously used LOAD_CLASSDEREF) and in annotation scopes within class bodies.

バージョン 3.12 で追加.

STORE_DEREF(i)

Stores STACK.pop() into the cell contained in slot i of the "fast locals" storage.

バージョン 3.11 で変更: i is no longer offset by the length of co_varnames.

DELETE_DEREF(i)

Empties the cell contained in slot i of the "fast locals" storage. Used by the del statement.

バージョン 3.2 で追加.

バージョン 3.11 で変更: i is no longer offset by the length of co_varnames.

COPY_FREE_VARS(n)

Copies the n free variables from the closure into the frame. Removes the need for special code on the caller's side when calling closures.

バージョン 3.11 で追加.

RAISE_VARARGS(argc)

Raises an exception using one of the 3 forms of the raise statement, depending on the value of argc:

  • 0: raise (re-raise previous exception)

  • 1: raise STACK[-1] (raise exception instance or type at STACK[-1])

  • 2: raise STACK[-2] from STACK[-1] (raise exception instance or type at STACK[-2] with __cause__ set to STACK[-1])

CALL(argc)

Calls a callable object with the number of arguments specified by argc, including the named arguments specified by the preceding KW_NAMES, if any. On the stack are (in ascending order), either:

  • NULL

  • The callable

  • The positional arguments

  • The named arguments

or:

  • The callable

  • self

  • The remaining positional arguments

  • The named arguments

argc is the total of the positional and named arguments, excluding self when a NULL is not present.

CALL pops all arguments and the callable object off the stack, calls the callable object with those arguments, and pushes the return value returned by the callable object.

バージョン 3.11 で追加.

CALL_FUNCTION_EX(flags)

Calls a callable object with variable set of positional and keyword arguments. If the lowest bit of flags is set, the top of the stack contains a mapping object containing additional keyword arguments. Before the callable is called, the mapping object and iterable object are each "unpacked" and their contents passed in as keyword and positional arguments respectively. CALL_FUNCTION_EX pops all arguments and the callable object off the stack, calls the callable object with those arguments, and pushes the return value returned by the callable object.

バージョン 3.6 で追加.

PUSH_NULL

Pushes a NULL to the stack. Used in the call sequence to match the NULL pushed by LOAD_METHOD for non-method calls.

バージョン 3.11 で追加.

KW_NAMES(consti)

Prefixes CALL. Stores a reference to co_consts[consti] into an internal variable for use by CALL. co_consts[consti] must be a tuple of strings.

バージョン 3.11 で追加.

MAKE_FUNCTION(flags)

Pushes a new function object on the stack. From bottom to top, the consumed stack must consist of values if the argument carries a specified flag value

  • 0x01 a tuple of default values for positional-only and positional-or-keyword parameters in positional order

  • 0x02 a dictionary of keyword-only parameters' default values

  • 0x04 a tuple of strings containing parameters' annotations

  • 0x08 a tuple containing cells for free variables, making a closure

  • the code associated with the function (at STACK[-1])

バージョン 3.10 で変更: Flag value 0x04 is a tuple of strings instead of dictionary

バージョン 3.11 で変更: Qualified name at STACK[-1] was removed.

BUILD_SLICE(argc)

Pushes a slice object on the stack. argc must be 2 or 3. If it is 2, implements:

end = STACK.pop()
start = STACK.pop()
STACK.append(slice(start, stop))

if it is 3, implements:

step = STACK.pop()
end = STACK.pop()
start = STACK.pop()
STACK.append(slice(start, end, step))

See the slice() built-in function for more information.

EXTENDED_ARG(ext)

Prefixes any opcode which has an argument too big to fit into the default one byte. ext holds an additional byte which act as higher bits in the argument. For each opcode, at most three prefixal EXTENDED_ARG are allowed, forming an argument from two-byte to four-byte.

FORMAT_VALUE(flags)

Used for implementing formatted literal strings (f-strings). Pops an optional fmt_spec from the stack, then a required value. flags is interpreted as follows:

  • (flags & 0x03) == 0x00: value is formatted as-is.

  • (flags & 0x03) == 0x01: call str() on value before formatting it.

  • (flags & 0x03) == 0x02: call repr() on value before formatting it.

  • (flags & 0x03) == 0x03: call ascii() on value before formatting it.

  • (flags & 0x04) == 0x04: pop fmt_spec from the stack and use it, else use an empty fmt_spec.

Formatting is performed using PyObject_Format(). The result is pushed on the stack.

バージョン 3.6 で追加.

MATCH_CLASS(count)

STACK[-1] is a tuple of keyword attribute names, STACK[-2] is the class being matched against, and STACK[-3] is the match subject. count is the number of positional sub-patterns.

Pop STACK[-1], STACK[-2], and STACK[-3]. If STACK[-3] is an instance of STACK[-2] and has the positional and keyword attributes required by count and STACK[-1], push a tuple of extracted attributes. Otherwise, push None.

バージョン 3.10 で追加.

バージョン 3.11 で変更: Previously, this instruction also pushed a boolean value indicating success (True) or failure (False).

RESUME(where)

A no-op. Performs internal tracing, debugging and optimization checks.

The where operand marks where the RESUME occurs:

  • 0 The start of a function, which is neither a generator, coroutine nor an async generator

  • 1 After a yield expression

  • 2 After a yield from expression

  • 3 After an await expression

バージョン 3.11 で追加.

RETURN_GENERATOR

Create a generator, coroutine, or async generator from the current frame. Used as first opcode of in code object for the above mentioned callables. Clear the current frame and return the newly created generator.

バージョン 3.11 で追加.

SEND(delta)

Equivalent to STACK[-1] = STACK[-2].send(STACK[-1]). Used in yield from and await statements.

If the call raises StopIteration, pop the top value from the stack, push the exception's value attribute, and increment the bytecode counter by delta.

バージョン 3.11 で追加.

HAVE_ARGUMENT

This is not really an opcode. It identifies the dividing line between opcodes in the range [0,255] which don't use their argument and those that do (< HAVE_ARGUMENT and >= HAVE_ARGUMENT, respectively).

If your application uses pseudo instructions, use the hasarg collection instead.

バージョン 3.6 で変更: Now every instruction has an argument, but opcodes < HAVE_ARGUMENT ignore it. Before, only opcodes >= HAVE_ARGUMENT had an argument.

バージョン 3.12 で変更: Pseudo instructions were added to the dis module, and for them it is not true that comparison with HAVE_ARGUMENT indicates whether they use their arg.

CALL_INTRINSIC_1

Calls an intrinsic function with one argument. Passes STACK[-1] as the argument and sets STACK[-1] to the result. Used to implement functionality that is not performance critical.

The operand determines which intrinsic function is called:

Operand

説明

INTRINSIC_1_INVALID

Not valid

INTRINSIC_PRINT

Prints the argument to standard out. Used in the REPL.

INTRINSIC_IMPORT_STAR

Performs import * for the named module.

INTRINSIC_STOPITERATION_ERROR

Extracts the return value from a StopIteration exception.

INTRINSIC_ASYNC_GEN_WRAP

Wraps an aync generator value

INTRINSIC_UNARY_POSITIVE

Performs the unary + operation

INTRINSIC_LIST_TO_TUPLE

Converts a list to a tuple

INTRINSIC_TYPEVAR

Creates a typing.TypeVar

INTRINSIC_PARAMSPEC

Creates a typing.ParamSpec

INTRINSIC_TYPEVARTUPLE

Creates a typing.TypeVarTuple

INTRINSIC_SUBSCRIPT_GENERIC

Returns typing.Generic subscripted with the argument

INTRINSIC_TYPEALIAS

Creates a typing.TypeAliasType; used in the type statement. The argument is a tuple of the type alias's name, type parameters, and value.

バージョン 3.12 で追加.

CALL_INTRINSIC_2

Calls an intrinsic function with two arguments. Used to implement functionality that is not performance critical:

arg2 = STACK.pop()
arg1 = STACK.pop()
result = intrinsic2(arg1, arg2)
STACK.push(result)

The operand determines which intrinsic function is called:

Operand

説明

INTRINSIC_2_INVALID

Not valid

INTRINSIC_PREP_RERAISE_STAR

Calculates the ExceptionGroup to raise from a try-except*.

INTRINSIC_TYPEVAR_WITH_BOUND

Creates a typing.TypeVar with a bound.

INTRINSIC_TYPEVAR_WITH_CONSTRAINTS

Creates a typing.TypeVar with constraints.

INTRINSIC_SET_FUNCTION_TYPE_PARAMS

Sets the __type_params__ attribute of a function.

バージョン 3.12 で追加.

Pseudo-instructions

These opcodes do not appear in Python bytecode. They are used by the compiler but are replaced by real opcodes or removed before bytecode is generated.

SETUP_FINALLY(target)

Set up an exception handler for the following code block. If an exception occurs, the value stack level is restored to its current state and control is transferred to the exception handler at target.

SETUP_CLEANUP(target)

Like SETUP_FINALLY, but in case of an exception also pushes the last instruction (lasti) to the stack so that RERAISE can restore it. If an exception occurs, the value stack level and the last instruction on the frame are restored to their current state, and control is transferred to the exception handler at target.

SETUP_WITH(target)

Like SETUP_CLEANUP, but in case of an exception one more item is popped from the stack before control is transferred to the exception handler at target.

This variant is used in with and async with constructs, which push the return value of the context manager's __enter__() or __aenter__() to the stack.

POP_BLOCK

Marks the end of the code block associated with the last SETUP_FINALLY, SETUP_CLEANUP or SETUP_WITH.

JUMP
JUMP_NO_INTERRUPT

Undirected relative jump instructions which are replaced by their directed (forward/backward) counterparts by the assembler.

LOAD_METHOD

Optimized unbound method lookup. Emitted as a LOAD_ATTR opcode with a flag set in the arg.

命令コードコレクション

これらのコレクションは、自動でバイトコード命令を解析するために提供されています:

バージョン 3.12 で変更: The collections now contain pseudo instructions and instrumented instructions as well. These are opcodes with values >= MIN_PSEUDO_OPCODE and >= MIN_INSTRUMENTED_OPCODE.

dis.opname

命令コード名のリスト。 バイトコードをインデックスに使って参照できます。

dis.opmap

命令コード名をバイトコードに対応づける辞書。

dis.cmp_op

すべての比較命令の名前のリスト。

dis.hasarg

Sequence of bytecodes that use their argument.

バージョン 3.12 で追加.

dis.hasconst

定数にアクセスするバイトコードのリスト。

dis.hasfree

Sequence of bytecodes that access a free variable. 'free' in this context refers to names in the current scope that are referenced by inner scopes or names in outer scopes that are referenced from this scope. It does not include references to global or builtin scopes.

dis.hasname

名前によって属性にアクセスするバイトコードのリスト。

dis.hasjrel

相対ジャンプ先を持つバイトコードのリスト。

dis.hasjabs

絶対ジャンプ先を持つバイトコードのリスト。

dis.haslocal

ローカル変数にアクセスするバイトコードのリスト。

dis.hascompare

ブール命令のバイトコードのリスト。

dis.hasexc

Sequence of bytecodes that set an exception handler.

バージョン 3.12 で追加.