`dis` --- Python バイトコードの逆アセンブラー¶

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.

バージョン 3.13 で変更: The output shows logical labels rather than instruction offsets for jump targets and exception handlers. The -O command line option and the show_offsets argument were added.

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           RESUME                   0

  3           LOAD_GLOBAL              1 (len + NULL)
              LOAD_FAST                0 (alist)
              CALL                     1
              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] [-C] [-O] [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。

-C, --show-caches¶: Show inline caches.

-O, --show-offsets¶: Show offsets of instructions.

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

バイトコード解析¶

Added in version 3.4.

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, show_offsets=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_line が None 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_offset が None 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.

If show_offsets is True, dis() will include instruction offsets in the output.

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。

Added in version 3.2.

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。

Added in version 3.2.

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.

distb(tb=None, *, file=None, show_caches=False, adaptive=False,

show_offset=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.

バージョン 3.13 で変更: Added the show_offsets parameter.

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

disco(code, lasti=-1, *, file=None, show_caches=False, adaptive=False,

show_offsets=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:

各行の最初の命令に対する行番号。
現在の命令。 --> として示されます。
ラベル付けされた命令。 >> とともに表示されます。
命令のアドレス。
命令コード名。
命令パラメタ。
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.

バージョン 3.13 で変更: Added the show_offsets parameter.

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_line が None 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 adaptive parameter works as it does in dis().

Added in version 3.4.

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

バージョン 3.13 で変更: The show_caches parameter is deprecated and has no effect. The iterator generates the Instruction instances with the cache_info field populated (regardless of the value of show_caches) and it no longer generates separate items for the cache entries.

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.

バージョン 3.13 で変更: Line numbers can be None for bytecode that does not map to source lines.

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.

Added in version 3.4.

バージョン 3.8 で変更: Added jump parameter.

バージョン 3.13 で変更: If oparg is omitted (or None), the stack effect is now returned for oparg=0. Previously this was an error for opcodes that use their arg. It is also no longer an error to pass an integer oparg when the opcode does not use it; the oparg in this case is ignored.

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

baseopcode¶: numeric code for the base operation if operation is specialized; otherwise equal to opcode

baseopname¶: human readable name for the base operation if operation is specialized; otherwise equal to opname

arg¶: (ある場合は) 命令の数値引数、無ければ None

oparg¶: alias for arg

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

start_offset¶: start index of operation within bytecode sequence, including prefixed EXTENDED_ARG operations if present; otherwise equal to offset

cache_offset¶: start index of the cache entries following the operation

end_offset¶: end index of the cache entries following the operation

starts_line¶: True if this opcode starts a source line, otherwise False

line_number¶: source line number associated with this opcode (if any), otherwise 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

jump_target¶: bytecode index of the jump target if this is a jump operation, otherwise None

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

Added in version 3.4.

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

バージョン 3.13 で変更: Changed field starts_line.

Added fields start_offset, cache_offset, end_offset, baseopname, baseopcode, jump_target, oparg, line_number and cache_info.

class dis.Positions¶

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

lineno¶

end_lineno¶

col_offset¶

end_col_offset¶

Added in version 3.11.

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-of-stack item. Equivalent to POP_TOP. Used to clean up at the end of loops, hence the name.

Added in version 3.12.

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

Added in version 3.12.

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])

Added in version 3.11.

SWAP(i)¶

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

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

Added in version 3.11.

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.

Added in version 3.11.

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].

バージョン 3.13 で変更: This instruction now requires an exact bool operand.

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]).

Added in version 3.5.

TO_BOOL¶: Implements STACK[-1] = bool(STACK[-1]).

Added in version 3.13.

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)

Added in version 3.11.

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])

Added in version 3.12.

STORE_SLICE¶

Implements:

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

Added in version 3.12.

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__

Added in version 3.5.

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__().

Added in version 3.5.

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.

Added in version 3.5.

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.

Added in version 3.8.

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].

Added in version 3.12.

BEFORE_ASYNC_WITH¶

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

STACK.extend((__aexit__, __aenter__())

Added in version 3.5.

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.

Added in version 3.1.

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.

Added in version 3.12.

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.

バージョン 3.13 で変更: oparg is 1 if this instruction is part of a yield-from or await, and 0 otherwise.

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.

Added in version 3.6.

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.

Added in version 3.9.

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.

Added in version 3.11.

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.

Added in version 3.11.

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.

Added in version 3.11.

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.

Added in version 3.9.

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.

Added in version 3.9.

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.

Added in version 3.11.

GET_LEN¶: Perform STACK.append(len(STACK[-1])). Used in match statements where comparison with structure of pattern is needed.

Added in version 3.10.

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.

Added in version 3.10.

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.

Added in version 3.10.

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.

Added in version 3.10.

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.

Added in version 3.12.

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.

Added in version 3.12.

BUILD_TUPLE(count)¶

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

if count == 0:
    value = ()
else:
    value = tuple(STACK[-count:])
    STACK = STACK[:-count]

STACK.append(value)

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.

Added in version 3.6.

BUILD_STRING(count)¶: Concatenates count strings from the stack and pushes the resulting string onto the stack.

Added in version 3.6.

LIST_EXTEND(i)¶

Implements:

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

Used to build lists.

Added in version 3.9.

SET_UPDATE(i)¶

Implements:

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

Used to build sets.

Added in version 3.9.

DICT_UPDATE(i)¶

Implements:

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

Used to build dicts.

Added in version 3.9.

DICT_MERGE(i)¶: Like DICT_UPDATE but raises an exception for duplicate keys.

Added in version 3.9.

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 or CALL_KW 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 NULL 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).

Added in version 3.12.

COMPARE_OP(opname)¶: Performs a Boolean operation. The operation name can be found in cmp_op[opname >> 5]. If the fifth-lowest bit of opname is set (opname & 16), the result should be coerced to bool.

バージョン 3.13 で変更: The fifth-lowest bit of the oparg now indicates a forced conversion to bool.

IS_OP(invert)¶: Performs is comparison, or is not if invert is 1.

Added in version 3.9.

CONTAINS_OP(invert)¶: Performs in comparison, or not in if invert is 1.

Added in version 3.9.

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.

Added in version 3.11.

JUMP_BACKWARD_NO_INTERRUPT(delta)¶: Decrements bytecode counter by delta. Does not check for interrupts.

Added in version 3.11.

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.

バージョン 3.13 で変更: This instruction now requires an exact bool operand.

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.

バージョン 3.13 で変更: This instruction now requires an exact bool operand.

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).

Added in version 3.11.

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).

Added in version 3.11.

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_LOAD_FAST(var_nums)¶: Pushes references to co_varnames[var_nums >> 4] and co_varnames[var_nums & 15] onto the stack.

Added in version 3.13.

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.

Added in version 3.12.

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.

Added in version 3.12.

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

STORE_FAST_STORE_FAST(var_nums)¶: Stores STACK[-1] into co_varnames[var_nums >> 4] and STACK[-2] into co_varnames[var_nums & 15].

Added in version 3.13.

STORE_FAST_LOAD_FAST(var_nums)¶: Stores STACK.pop() into the local co_varnames[var_nums >> 4] and pushes a reference to the local co_varnames[var_nums & 15] onto the stack.

Added in version 3.13.

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.

Added in version 3.11.

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 closure variables in class bodies (which previously used LOAD_CLASSDEREF) and in annotation scopes within class bodies.

Added in version 3.12.

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.

Added in version 3.2.

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

Added in version 3.11.

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. On the stack are (in ascending order):

The callable
self or NULL
The remaining positional arguments

argc is the total of the positional arguments, excluding self.

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.

Added in version 3.11.

バージョン 3.13 で変更: The callable now always appears at the same position on the stack.

バージョン 3.13 で変更: Calls with keyword arguments are now handled by CALL_KW.

CALL_KW(argc)¶

Calls a callable object with the number of arguments specified by argc, including one or more named arguments. On the stack are (in ascending order):

The callable
self or NULL
The remaining positional arguments
The named arguments
A tuple of keyword argument names

argc is the total of the positional and named arguments, excluding self. The length of the tuple of keyword argument names is the number of named arguments.

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

Added in version 3.13.

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.

Added in version 3.6.

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.

Added in version 3.11.

MAKE_FUNCTION¶: Pushes a new function object on the stack built from the code object 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.

バージョン 3.13 で変更: Extra function attributes on the stack, signaled by oparg flags, were removed. They now use SET_FUNCTION_ATTRIBUTE.

SET_FUNCTION_ATTRIBUTE(flag)¶

Sets an attribute on a function object. Expects the function at STACK[-1] and the attribute value to set at STACK[-2]; consumes both and leaves the function at STACK[-1]. The flag determines which attribute to set:

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

Added in version 3.13.

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, end))

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.

CONVERT_VALUE(oparg)¶

Convert value to a string, depending on oparg:

value = STACK.pop()
result = func(value)
STACK.append(result)

oparg == 1: call str() on value
oparg == 2: call repr() on value
oparg == 3: call ascii() on value

Used for implementing formatted literal strings (f-strings).

Added in version 3.13.

FORMAT_SIMPLE¶

Formats the value on top of stack:

value = STACK.pop()
result = value.__format__("")
STACK.append(result)

Used for implementing formatted literal strings (f-strings).

Added in version 3.13.

FORMAT_WITH_SPEC¶

Formats the given value with the given format spec:

spec = STACK.pop()
value = STACK.pop()
result = value.__format__(spec)
STACK.append(result)

Used for implementing formatted literal strings (f-strings).

Added in version 3.13.

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.

Added in version 3.10.

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(context)¶

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

The context oparand consists of two parts. The lowest two bits indicate 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

The next bit is 1 if the RESUME is at except-depth 1, and 0 otherwise.

Added in version 3.11.

バージョン 3.13 で変更: The oparg value changed to include information about except-depth

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.

Added in version 3.11.

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.

Added in version 3.11.

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 or specialized 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.

バージョン 3.13 で非推奨: Use hasarg instead.

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 async 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.

Added in version 3.12.

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.append(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.

Added in version 3.12.

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_CLOSURE(i)¶

Pushes a reference to the cell contained in slot i of the "fast locals" storage.

Note that LOAD_CLOSURE is replaced with LOAD_FAST in the assembler.

バージョン 3.13 で変更: This opcode is now a pseudo-instruction.

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.

Added in version 3.12.

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 (closure) 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.hasjump¶: Sequence of bytecodes that have a jump target. All jumps are relative.

Added in version 3.13.

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.

Added in version 3.12.

dis.hasjrel¶: 相対ジャンプ先を持つバイトコードのリスト。

バージョン 3.13 で非推奨: All jumps are now relative. Use hasjump.

dis.hasjabs¶: 絶対ジャンプ先を持つバイトコードのリスト。

バージョン 3.13 で非推奨: All jumps are now relative. This list is empty.

`dis` --- Python バイトコードの逆アセンブラー¶

コマンドライン・インターフェース¶

バイトコード解析¶

解析関数¶

Python バイトコード命令¶

命令コードコレクション¶

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dis --- Python バイトコードの逆アセンブラー¶

コマンドライン・インターフェース¶

バイトコード解析¶

解析関数¶

Python バイトコード命令¶

命令コードコレクション¶

`dis` --- Python バイトコードの逆アセンブラー¶