# `dis` --- Python bytecode的反組譯器

原始碼：Lib/dis.py

`dis` 模組支援反組譯分析 CPython bytecode。CPython bytecode 作為輸入的模組被定義於 `Include/opcode.h` 並且被編譯器和直譯器所使用。

CPython implementation 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.

3.6 版更變: Use 2 bytes for each instruction. Previously the number of bytes varied by instruction.

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 LOAD_GLOBAL              0 (len)
                  2 LOAD_FAST                0 (alist)
                  4 CALL_FUNCTION            1
                  6 RETURN_VALUE

(The "2" is a line number).

## Bytecode analysis

3.4 版新加入.

The bytecode analysis API allows pieces of Python code to be wrapped in a `Bytecode` object that provides easy access to details of the compiled code.

class `dis.``Bytecode`(x, *, first_line=None, current_offset=None)

  Analyse the bytecode corresponding to a function, generator, asynchronous generator, coroutine, method, string of source code, or a code object (as returned by `compile()`).

  This is a convenience wrapper around many of the functions listed below, most notably `get_instructions()`, as iterating over a `Bytecode` instance yields the bytecode operations as `Instruction` instances.

  If first_line is not `None`, it indicates the line number that should be reported for the first source line in the disassembled code. Otherwise, the source line information (if any) is taken directly from the disassembled code object.

  If current_offset is not `None`, it refers to an instruction offset in the disassembled code. Setting this means `dis()` will display a "current instruction" marker against the specified opcode.

  classmethod `from_traceback`(tb)

    Construct a `Bytecode` instance from the given traceback, setting current_offset to the instruction responsible for the exception.

  `codeobj`

    The compiled code object.

  `first_line`

    The first source line of the code object (if available)

  `dis`()

    Return a formatted view of the bytecode operations (the same as printed by `dis.dis()`, but returned as a multi-line string).

  `info`()

    Return a formatted multi-line string with detailed information about the code object, like `code_info()`.

  3.7 版更變: This can now handle coroutine and asynchronous generator objects.

Example:

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

## Analysis functions

The `dis` module also defines the following analysis functions that convert the input directly to the desired output. They can be useful if only a single operation is being performed, so the intermediate analysis object isn't useful:

`dis.``code_info`(x)

  Return a formatted multi-line string with detailed code object information for the supplied function, generator, asynchronous generator, coroutine, 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.

  3.2 版新加入.

  3.7 版更變: This can now handle coroutine and asynchronous generator objects.

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

  Print detailed code object information for the supplied function, method, source code string or code object to file (or `sys.stdout` if file is not specified).

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

  3.2 版新加入.

  3.4 版更變: Added file parameter.

`dis.``dis`(x=None, *, file=None, depth=None)

  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 (the code of comprehensions, generator expressions and nested functions, and the code used for building nested classes). 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.

  The disassembly is written as text to the supplied file argument if provided and to `sys.stdout` otherwise.

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

  3.4 版更變: Added file parameter.

  3.7 版更變: Implemented recursive disassembling and added depth parameter.

  3.7 版更變: This can now handle coroutine and asynchronous generator objects.

`dis.``distb`(tb=None, *, file=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.

  The disassembly is written as text to the supplied file argument if provided and to `sys.stdout` otherwise.

  3.4 版更變: Added file parameter.

`dis.``disassemble`(code, lasti=-1, *, file=None)
`dis.``disco`(code, lasti=-1, *, file=None)

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

  1. the line number, for the first instruction of each line

  2. the current instruction, indicated as `-->`,

  3. a labelled instruction, indicated with `>>`,

  4. the address of the instruction,

  5. the operation code name,

  6. operation parameters, and

  7. interpretation of the parameters in parentheses.

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

  The disassembly is written as text to the supplied file argument if provided and to `sys.stdout` otherwise.

  3.4 版更變: Added file parameter.

`dis.``get_instructions`(x, *, first_line=None)

  Return an iterator over the instructions in the supplied function, method, source code string or code object.

  The iterator generates a series of `Instruction` named tuples giving the details of each operation in the supplied code.

  If first_line is not `None`, it indicates the line number that should be reported for the first source line in the disassembled code. Otherwise, the source line information (if any) is taken directly from the disassembled code object.

  3.4 版新加入.

`dis.``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. See Objects/lnotab_notes.txt for the `co_lnotab` format and how to decode it.

  3.6 版更變: Line numbers can be decreasing. Before, they were always increasing.

`dis.``findlabels`(code)

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

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

  Compute the stack effect of opcode with argument oparg.

  如果代码有一个跳转目标并且 jump 是 `True` ，则 `drag_effect()` 将返回跳转的堆栈效果。如果 jump 是 `False` ，它将返回不跳跃的堆栈效果。如果 jump 是 `None` （默认值），它将返回两种情况的最大堆栈效果。

  3.4 版新加入.

  3.8 版更變: 添加 jump 参数。

## Python Bytecode Instructions

The `get_instructions()` function and `Bytecode` class provide details of bytecode instructions as `Instruction` instances:

class `dis.``Instruction`

  Details for a bytecode operation

  `opcode`

    numeric code for operation, corresponding to the opcode values listed below and the bytecode values in the Opcode collections.

  `opname`

    human readable name for operation

  `arg`

    numeric argument to operation (if any), otherwise `None`

  `argval`

    resolved arg value (if known), otherwise same as arg

  `argrepr`

    human readable description of operation argument

  `offset`

    start index of operation within bytecode sequence

  `starts_line`

    line started by this opcode (if any), otherwise `None`

  `is_jump_target`

    `True` if other code jumps to here, otherwise `False`

  3.4 版新加入.

The Python compiler currently generates the following bytecode instructions.

General instructions

`NOP`

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

`POP_TOP`

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

`ROT_TWO`

  Swaps the two top-most stack items.

`ROT_THREE`

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

`ROT_FOUR`

  将第二个，第三个和第四个堆栈项向上提升一个位置，将顶项移动到第四个位置。

  3.8 版新加入.

`DUP_TOP`

  Duplicates the reference on top of the stack.

  3.2 版新加入.

`DUP_TOP_TWO`

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

  3.2 版新加入.

Unary operations

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

`UNARY_POSITIVE`

  Implements `TOS = +TOS`.

`UNARY_NEGATIVE`

  Implements `TOS = -TOS`.

`UNARY_NOT`

  Implements `TOS = not TOS`.

`UNARY_INVERT`

  Implements `TOS = ~TOS`.

`GET_ITER`

  Implements `TOS = iter(TOS)`.

`GET_YIELD_FROM_ITER`

  If `TOS` is a generator iterator or coroutine object it is left as is. Otherwise, implements `TOS = iter(TOS)`.

  3.5 版新加入.

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.

`BINARY_POWER`

  Implements `TOS = TOS1 ** TOS`.

`BINARY_MULTIPLY`

  Implements `TOS = TOS1 * TOS`.

`BINARY_MATRIX_MULTIPLY`

  Implements `TOS = TOS1 @ TOS`.

  3.5 版新加入.

`BINARY_FLOOR_DIVIDE`

  Implements `TOS = TOS1 // TOS`.

`BINARY_TRUE_DIVIDE`

  Implements `TOS = TOS1 / TOS`.

`BINARY_MODULO`

  Implements `TOS = TOS1 % TOS`.

`BINARY_ADD`

  Implements `TOS = TOS1 + TOS`.

`BINARY_SUBTRACT`

  Implements `TOS = TOS1 - TOS`.

`BINARY_SUBSCR`

  Implements `TOS = TOS1[TOS]`.

`BINARY_LSHIFT`

  Implements `TOS = TOS1 << TOS`.

`BINARY_RSHIFT`

  Implements `TOS = TOS1 >> TOS`.

`BINARY_AND`

  Implements `TOS = TOS1 & TOS`.

`BINARY_XOR`

  Implements `TOS = TOS1 ^ TOS`.

`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.

`INPLACE_POWER`

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

`INPLACE_MULTIPLY`

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

`INPLACE_MATRIX_MULTIPLY`

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

  3.5 版新加入.

`INPLACE_FLOOR_DIVIDE`

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

`INPLACE_TRUE_DIVIDE`

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

`INPLACE_MODULO`

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

`INPLACE_ADD`

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

`INPLACE_SUBTRACT`

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

`INPLACE_LSHIFT`

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

`INPLACE_RSHIFT`

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

`INPLACE_AND`

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

`INPLACE_XOR`

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

`INPLACE_OR`

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

`STORE_SUBSCR`

  Implements `TOS1[TOS] = TOS2`.

`DELETE_SUBSCR`

  Implements `del TOS1[TOS]`.

Coroutine opcodes

`GET_AWAITABLE`

  Implements `TOS = get_awaitable(TOS)`, 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__`.

  3.5 版新加入.

`GET_AITER`

  Implements `TOS = TOS.__aiter__()`.

  3.5 版新加入.

  3.7 版更變: Returning awaitable objects from `__aiter__` is no longer supported.

`GET_ANEXT`

  Implements `PUSH(get_awaitable(TOS.__anext__()))`. See `GET_AWAITABLE` for details about `get_awaitable`

  3.5 版新加入.

`END_ASYNC_FOR`

  终止一个 `async for` 循环。处理等待下一个项目时引发的异常。如果 TOS 是 `StopAsyncIteration`， 从堆栈弹出7个值，并使用后三个恢复异常状态。否则，使用堆栈中的三个值重新引发异常。从块堆栈中删除异常处理程序块。

  3.8 版新加入.

`BEFORE_ASYNC_WITH`

  Resolves `__aenter__` and `__aexit__` from the object on top of the stack. Pushes `__aexit__` and result of `__aenter__()` to the stack.

  3.5 版新加入.

`SETUP_ASYNC_WITH`

  Creates a new frame object.

  3.5 版新加入.

Miscellaneous opcodes

`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_TOP`.

`SET_ADD`(i)

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

`LIST_APPEND`(i)

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

`MAP_ADD`(i)

  调用 `dict.__setitem__(TOS1[-i], TOS1, TOS)` 。 用于实现字典推导。

  3.1 版新加入.

  3.8 版更變: 映射值为 TOS ，映射键为 TOS1 。之前，它们被颠倒了。

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.

`RETURN_VALUE`

  Returns with TOS to the caller of the function.

`YIELD_VALUE`

  Pops TOS and yields it from a generator.

`YIELD_FROM`

  Pops TOS and delegates to it as a subiterator from a generator.

  3.3 版新加入.

`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.

  3.6 版新加入.

`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 *`.

`POP_BLOCK`

  从块堆栈中删除一个块。有一块堆栈，每帧用于表示 `try` 语句等。

`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.

`POP_FINALLY`(preserve_tos)

  清除值堆栈和块堆栈。如果 preserve_tos 不是 `0` ，则在执行其他堆栈操作后，首先从堆栈中弹出 TOS 并将其推入堆栈：

  - 如果TOS是 `NULL` 或整数（由 `BEGIN_FINALLY` 或 `CALL_FINALLY` 推入），它将从堆栈中弹出。

  - 如果TOS是异常类型（在引发异常时被推入），则从堆栈中弹出6个值，最后三个弹出值用于恢复异常状态。从块堆栈中删除异常处理程序块。

  它类似于 `END_FINALLY` ，但不会更改字节码计数器也不会引发异常。用于在 `finally` 块中实现 `break` 、 `continue` 和 `return` 。

  3.8 版新加入.

`BEGIN_FINALLY`

  将 `NULL` 推入堆栈以便在以下操作中使用 `END_FINALLY` 、 `POP_FINALLY` 、 `WITH_CLEANUP_START` 和 `WITH_CLEANUP_FINISH` 。开始 `finally` 块。

  3.8 版新加入.

`END_FINALLY`

  终止 `finally` 子句。解释器回溯是否有必须重新抛出异常的情况或根据 TOS 的值继续执行。

  - 如果 TOS 是 `NULL` （由 `BEGIN_FINALLY` 推入）继续下一条指令。 TOS 被弹出。

  - 如果 TO S是一个整数（由 `CALL_FINALLY` 推入），则将字节码计数器设置为 TOS 。 TOS 被弹出。

  - 如果TOS是异常类型（在引发异常时被推送），则从堆栈中弹出 6 个值，前三个弹出值用于重新引发异常，最后三个弹出值用于恢复异常状态。从块堆栈中删除异常处理程序块。

`LOAD_BUILD_CLASS`

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

`SETUP_WITH`(delta)

  此操作码在 with 块开始之前执行多个操作。首先，它从上下文管理器加载 `__exit__()` 并将其推入到堆栈以供以后被 `WITH_CLEANUP_START` 使用。然后，调用 `__enter__()` ，并推入指向 delta 的 finally 块。最后，调用 `__enter__()` 方法的结果被压入堆栈。一个操作码将忽略它（ `POP_TOP` ），或将其存储在一个或多个变量（ `STORE_FAST` 、 `STORE_NAME` 或 `UNPACK_SEQUENCE` ）中。

  3.2 版新加入.

`WITH_CLEANUP_START`

  当 `with` 语句块退出时，开始清理堆栈。

  在堆栈的顶部是 `NULL` （由 `BEGIN_FINALLY` 推送）或者如果在 with 块中引发了异常，则推送 6 个值。下面是上下文管理器 `__exit__()` 或 `__aexit__()` 绑定方法。

  如果TOS是 `NULL` ，则调用 `SECOND(None, None, None)` ，从堆栈中删除函数，离开 TOS ，并将 `None` 推送到堆栈。 否则调用 `SEVENTH(TOP, SECOND, THIRD)` ，将堆栈的底部3值向下移动，用 `NULL` 替换空位并推入 TOS 。最后拖入调用的结果。

`WITH_CLEANUP_FINISH`

  当 `with` 语句块退出时，完成清理堆栈。

  TOS 是 `WITH_CLEANUP_START` 推送的 `__exit__()` 或 `__aexit__()` 函数的结果。 SECOND是 `None` 或异常类型（引发异常时推入的）。

  从堆栈中弹出两个值。如果 SECOND 不为 None 并且 TOS 为 true ，则展开 EXCEPT_HANDLER 块，该块是在捕获异常时创建的，并将 `NULL` 推入堆栈。

All of the following opcodes use their arguments.

`STORE_NAME`(namei)

  Implements `name = TOS`. 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 TOS into count individual values, which are put onto the stack right-to-left.

`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 of 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.

`STORE_ATTR`(namei)

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

`DELETE_ATTR`(namei)

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

`STORE_GLOBAL`(namei)

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

`DELETE_GLOBAL`(namei)

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

`LOAD_CONST`(consti)

  Pushes `co_consts[consti]` onto the stack.

`LOAD_NAME`(namei)

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

`BUILD_TUPLE`(count)

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

`BUILD_LIST`(count)

  Works as `BUILD_TUPLE`, but creates a list.

`BUILD_SET`(count)

  Works as `BUILD_TUPLE`, but creates a set.

`BUILD_MAP`(count)

  Pushes a new dictionary object onto the stack. Pops `2 * count` items so that the dictionary holds count entries: `{..., TOS3: TOS2, TOS1: TOS}`.

  3.5 版更變: 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. count values are consumed from the stack. The top element on the stack contains a tuple of keys.

  3.6 版新加入.

`BUILD_STRING`(count)

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

  3.6 版新加入.

`BUILD_TUPLE_UNPACK`(count)

  Pops count iterables from the stack, joins them in a single tuple, and pushes the result. Implements iterable unpacking in tuple displays `(*x, *y, *z)`.

  3.5 版新加入.

`BUILD_TUPLE_UNPACK_WITH_CALL`(count)

  This is similar to `BUILD_TUPLE_UNPACK`, but is used for `f(*x, *y, *z)` call syntax. The stack item at position `count + 1` should be the corresponding callable `f`.

  3.6 版新加入.

`BUILD_LIST_UNPACK`(count)

  This is similar to `BUILD_TUPLE_UNPACK`, but pushes a list instead of tuple. Implements iterable unpacking in list displays `[*x, *y, *z]`.

  3.5 版新加入.

`BUILD_SET_UNPACK`(count)

  This is similar to `BUILD_TUPLE_UNPACK`, but pushes a set instead of tuple. Implements iterable unpacking in set displays `{*x, *y, *z}`.

  3.5 版新加入.

`BUILD_MAP_UNPACK`(count)

  Pops count mappings from the stack, merges them into a single dictionary, and pushes the result. Implements dictionary unpacking in dictionary displays `{**x, **y, **z}`.

  3.5 版新加入.

`BUILD_MAP_UNPACK_WITH_CALL`(count)

  This is similar to `BUILD_MAP_UNPACK`, but is used for `f(**x, **y, **z)` call syntax. The stack item at position `count + 2` should be the corresponding callable `f`.

  3.5 版新加入.

  3.6 版更變: The position of the callable is determined by adding 2 to the opcode argument instead of encoding it in the second byte of the argument.

`LOAD_ATTR`(namei)

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

`COMPARE_OP`(opname)

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

`IMPORT_NAME`(namei)

  Imports the module `co_names[namei]`. TOS and TOS1 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 TOS. The resulting object is pushed onto the stack, to be subsequently stored by a `STORE_FAST` instruction.

`JUMP_FORWARD`(delta)

  Increments bytecode counter by delta.

`POP_JUMP_IF_TRUE`(target)

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

  3.1 版新加入.

`POP_JUMP_IF_FALSE`(target)

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

  3.1 版新加入.

`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.

  3.1 版新加入.

`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.

  3.1 版新加入.

`JUMP_ABSOLUTE`(target)

  Set bytecode counter to target.

`FOR_ITER`(delta)

  TOS 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 TOS is popped, and the byte code counter is incremented by delta.

`LOAD_GLOBAL`(namei)

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

`SETUP_FINALLY`(delta)

  将一个来自 try-finally 或 try-except 子句的 try 代码块推入代码块栈顶。 相对 finally 代码块或第一个 except 代码块 delta 个点数。

`CALL_FINALLY`(delta)

  将下一条指令的地址推入栈顶并将字节码计数器的值增加 delta。 用于将 finally 代码块作为一个“子例程”调用。

  3.8 版新加入.

`LOAD_FAST`(var_num)

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

`STORE_FAST`(var_num)

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

`DELETE_FAST`(var_num)

  Deletes local `co_varnames[var_num]`.

`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)]`.

`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.

`LOAD_CLASSDEREF`(i)

  Much like `LOAD_DEREF` but first checks the locals dictionary before consulting the cell. This is used for loading free variables in class bodies.

  3.4 版新加入.

`STORE_DEREF`(i)

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

`DELETE_DEREF`(i)

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

  3.2 版新加入.

`RAISE_VARARGS`(argc)

  使用 `raise` 语句的 3 种形式之一引发异常，具体形式取决于 argc 的值：

  - 0: `raise` (重新引发之前的异常)

  - 1: `raise TOS` (在 `TOS` 上引发异常实例或类型)

  - 2: `raise TOS1 from TOS` (在 `TOS1` 上引发异常实例或类型并将 `__cause__` 设为 `TOS`)

`CALL_FUNCTION`(argc)

  Calls a callable object with positional arguments. argc indicates the number of positional arguments. The top of the stack contains positional arguments, with the right-most argument on top. Below the arguments is a callable object to call. `CALL_FUNCTION` 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.

  3.6 版更變: This opcode is used only for calls with positional arguments.

`CALL_FUNCTION_KW`(argc)

  Calls a callable object with positional (if any) and keyword arguments. argc indicates the total number of positional and keyword arguments. The top element on the stack contains a tuple of keyword argument names. Below that are keyword arguments in the order corresponding to the tuple. Below that are positional arguments, with the right-most parameter on top. Below the arguments is a callable object to call. `CALL_FUNCTION_KW` 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.

  3.6 版更變: Keyword arguments are packed in a tuple instead of a dictionary, argc indicates the total number of arguments.

`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. Below that is an iterable object containing positional arguments and a callable object to call. `BUILD_MAP_UNPACK_WITH_CALL` and `BUILD_TUPLE_UNPACK_WITH_CALL` can be used for merging multiple mapping objects and iterables containing 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.

  3.6 版新加入.

`LOAD_METHOD`(namei)

  Loads a method named `co_names[namei]` from TOS object. TOS is popped and method and TOS are pushed when interpreter can call unbound method directly. TOS will be used as the first argument (`self`) by `CALL_METHOD`. Otherwise, `NULL` and method is pushed (method is bound method or something else).

  3.7 版新加入.

`CALL_METHOD`(argc)

  Calls a method. argc is number of positional arguments. Keyword arguments are not supported. This opcode is designed to be used with `LOAD_METHOD`. Positional arguments are on top of the stack. Below them, two items described in `LOAD_METHOD` on the stack. All of them are popped and return value is pushed.

  3.7 版新加入.

`MAKE_FUNCTION`(argc)

  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` an annotation dictionary

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

  - the code associated with the function (at TOS1)

  - the qualified name of the function (at TOS)

`BUILD_SLICE`(argc)

  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 `slice()` built-in function for more information.

`EXTENDED_ARG`(ext)

  为任意带有大到无法放入默认的单字节的参数的操作码添加前缀。 ext 存放一个附加字节作为参数中的高比特位。 对于每个操作码，最多允许三个 `EXTENDED_ARG` 前缀，构成两字节到三字节的参数。

`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.

  3.6 版新加入.

`HAVE_ARGUMENT`

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

  3.6 版更變: Now every instruction has an argument, but opcodes `< HAVE_ARGUMENT` ignore it. Before, only opcodes `>= HAVE_ARGUMENT` had an argument.

## Opcode collections

These collections are provided for automatic introspection of bytecode instructions:

`dis.``opname`

  Sequence of operation names, indexable using the bytecode.

`dis.``opmap`

  Dictionary mapping operation names to bytecodes.

`dis.``cmp_op`

  Sequence of all compare operation names.

`dis.``hasconst`

  Sequence of bytecodes that access a constant.

`dis.``hasfree`

  Sequence of bytecodes that access a free variable (note that '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`

  Sequence of bytecodes that access an attribute by name.

`dis.``hasjrel`

  Sequence of bytecodes that have a relative jump target.

`dis.``hasjabs`

  Sequence of bytecodes that have an absolute jump target.

`dis.``haslocal`

  Sequence of bytecodes that access a local variable.

`dis.``hascompare`

  Sequence of bytecodes of Boolean operations.