32.12. dis
--- Disassembler for Python bytecode¶
Source code: Lib/dis.py
The dis
module supports the analysis of CPython bytecode by
disassembling it. The CPython bytecode which this module takes as an input is
defined in the file Include/opcode.h
and used by the compiler and the
interpreter.
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.
在 3.6 版更改: 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).
32.12.1. Bytecode analysis¶
3.4 新版功能.
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, 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 aBytecode
instance yields the bytecode operations asInstruction
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 meansdis()
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()
.
-
classmethod
Example:
>>> bytecode = dis.Bytecode(myfunc)
>>> for instr in bytecode:
... print(instr.opname)
...
LOAD_GLOBAL
LOAD_FAST
CALL_FUNCTION
RETURN_VALUE
32.12.2. 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, 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 新版功能.
-
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 新版功能.
在 3.4 版更改: Added file parameter.
-
dis.
dis
(x=None, *, file=None)¶ Disassemble the x object. x can denote either a module, a class, a method, a function, a generator, 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. 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.在 3.4 版更改: Added file parameter.
-
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.在 3.4 版更改: 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:
- the line number, for the first instruction of each line
- the current instruction, indicated as
-->
, - a labelled instruction, indicated with
>>
, - the address of the instruction,
- the operation code name,
- operation parameters, and
- interpretation of the parameters in parentheses.
The parameter interpretation recognizes local and global variable names, constant values, branch targets, and compare operators.
The disassembly is written as text to the supplied file argument if provided and to
sys.stdout
otherwise.在 3.4 版更改: 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 新版功能.
-
dis.
findlinestarts
(code)¶ This generator function uses the
co_firstlineno
andco_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 theco_lnotab
format and how to decode it.在 3.6 版更改: 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])¶ Compute the stack effect of opcode with argument oparg.
3.4 新版功能.
32.12.3. 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, otherwiseFalse
3.4 新版功能.
-
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.
-
DUP_TOP
¶ Duplicates the reference on top of the stack.
3.2 新版功能.
-
DUP_TOP_TWO
¶ Duplicates the two references on top of the stack, leaving them in the same order.
3.2 新版功能.
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, implementsTOS = iter(TOS)
.3.5 新版功能.
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 新版功能.
-
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 新版功能.
-
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)
, whereget_awaitable(o)
returnso
ifo
is a coroutine object or a generator object with the CO_ITERABLE_COROUTINE flag, or resolveso.__await__
.3.5 新版功能.
-
GET_AITER
¶ Implements
TOS = get_awaitable(TOS.__aiter__())
. SeeGET_AWAITABLE
for details aboutget_awaitable
3.5 新版功能.
-
GET_ANEXT
¶ Implements
PUSH(get_awaitable(TOS.__anext__()))
. SeeGET_AWAITABLE
for details aboutget_awaitable
3.5 新版功能.
-
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 新版功能.
-
SETUP_ASYNC_WITH
¶ Creates a new frame object.
3.5 新版功能.
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
.
-
CONTINUE_LOOP
(target)¶ Continues a loop due to a
continue
statement. target is the address to jump to (which should be aFOR_ITER
instruction).
-
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)¶ Calls
dict.setitem(TOS1[-i], TOS, TOS1)
. Used to implement dict comprehensions.3.1 新版功能.
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.
-
SETUP_ANNOTATIONS
¶ Checks whether
__annotations__
is defined inlocals()
, if not it is set up to an emptydict
. This opcode is only emitted if a class or module body contains variable annotations statically.3.6 新版功能.
-
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 implementsfrom module import *
.
-
POP_BLOCK
¶ Removes one block from the block stack. Per frame, there is a stack of blocks, denoting nested loops, try statements, and such.
-
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.
-
END_FINALLY
¶ Terminates a
finally
clause. The interpreter recalls whether the exception has to be re-raised, or whether the function returns, and continues with the outer-next block.
-
LOAD_BUILD_CLASS
¶ Pushes
builtins.__build_class__()
onto the stack. It is later called byCALL_FUNCTION
to construct a class.
-
SETUP_WITH
(delta)¶ 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 byWITH_CLEANUP
. Then,__enter__()
is called, and a finally block pointing to delta is pushed. Finally, the result of calling the enter method is pushed onto the stack. The next opcode will either ignore it (POP_TOP
), or store it in (a) variable(s) (STORE_FAST
,STORE_NAME
, orUNPACK_SEQUENCE
).3.2 新版功能.
-
WITH_CLEANUP_START
¶ Cleans up the stack when a
with
statement block exits. TOS is the context manager's__exit__()
bound method. Below TOS are 1--3 values indicating how/why the finally clause was entered:- SECOND =
None
- (SECOND, THIRD) = (
WHY_{RETURN,CONTINUE}
), retval - SECOND =
WHY_*
; no retval below it - (SECOND, THIRD, FOURTH) = exc_info()
In the last case,
TOS(SECOND, THIRD, FOURTH)
is called, otherwiseTOS(None, None, None)
. Pushes SECOND and result of the call to the stack.- SECOND =
-
WITH_CLEANUP_FINISH
¶ Pops exception type and result of 'exit' function call from the stack.
If the stack represents an exception, and the function call returns a 'true' value, this information is "zapped" and replaced with a single
WHY_SILENCED
to preventEND_FINALLY
from re-raising the exception. (But non-local gotos will still be resumed.)
All of the following opcodes use their arguments.
-
STORE_NAME
(namei)¶ Implements
name = TOS
. namei is the index of name in the attributeco_names
of the code object. The compiler tries to useSTORE_FAST
orSTORE_GLOBAL
if possible.
-
DELETE_NAME
(namei)¶ Implements
del name
, where namei is the index intoco_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 inco_names
.
-
DELETE_ATTR
(namei)¶ Implements
del TOS.name
, using namei as index intoco_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}
.在 3.5 版更改: 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 新版功能.
-
BUILD_STRING
(count)¶ Concatenates count strings from the stack and pushes the resulting string onto the stack.
3.6 新版功能.
-
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 新版功能.
-
BUILD_TUPLE_UNPACK_WITH_CALL
(count)¶ This is similar to
BUILD_TUPLE_UNPACK
, but is used forf(*x, *y, *z)
call syntax. The stack item at positioncount + 1
should be the corresponding callablef
.3.6 新版功能.
-
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 新版功能.
-
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 新版功能.
-
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 新版功能.
-
BUILD_MAP_UNPACK_WITH_CALL
(count)¶ This is similar to
BUILD_MAP_UNPACK
, but is used forf(**x, **y, **z)
call syntax. The stack item at positioncount + 2
should be the corresponding callablef
.3.5 新版功能.
在 3.6 版更改: 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 subsequentSTORE_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 aSTORE_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 新版功能.
-
POP_JUMP_IF_FALSE
(target)¶ If TOS is false, sets the bytecode counter to target. TOS is popped.
3.1 新版功能.
-
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 新版功能.
-
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 新版功能.
-
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_LOOP
(delta)¶ Pushes a block for a loop onto the block stack. The block spans from the current instruction with a size of delta bytes.
-
SETUP_EXCEPT
(delta)¶ Pushes a try block from a try-except clause onto the block stack. delta points to the first except block.
-
SETUP_FINALLY
(delta)¶ Pushes a try block from a try-except clause onto the block stack. delta points to the finally block.
-
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]
.
-
STORE_ANNOTATION
(namei)¶ Stores TOS as
locals()['__annotations__'][co_names[namei]] = TOS
.3.6 新版功能.
-
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 isco_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 新版功能.
-
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 新版功能.
-
RAISE_VARARGS
(argc)¶ Raises an exception. argc indicates the number of parameters to the raise statement, ranging from 0 to 3. The handler will find the traceback as TOS2, the parameter as TOS1, and the exception as TOS.
-
CALL_FUNCTION
(argc)¶ Calls a function. argc indicates the number of positional arguments. The positional arguments are on the stack, with the right-most argument on top. Below the arguments, the function object to call is on the stack. Pops all function arguments, and the function itself off the stack, and pushes the return value.
在 3.6 版更改: This opcode is used only for calls with positional arguments.
-
CALL_FUNCTION_KW
(argc)¶ Calls a function. argc indicates the number of arguments (positional and keyword). The top element on the stack contains a tuple of keyword argument names. Below the tuple, keyword arguments are on the stack, in the order corresponding to the tuple. Below the keyword arguments, the positional arguments are on the stack, with the right-most parameter on top. Below the arguments, the function object to call is on the stack. Pops all function arguments, and the function itself off the stack, and pushes the return value.
在 3.6 版更改: Keyword arguments are packed in a tuple instead of a dictionary, argc indicates the total number of arguments
-
CALL_FUNCTION_EX
(flags)¶ Calls a function. The lowest bit of flags indicates whether the var-keyword argument is placed at the top of the stack. Below the var-keyword argument, the var-positional argument is on the stack. Below the arguments, the function object to call is placed. Pops all function arguments, and the function itself off the stack, and pushes the return value. Note that this opcode pops at most three items from the stack. Var-positional and var-keyword arguments are packed by
BUILD_TUPLE_UNPACK_WITH_CALL
andBUILD_MAP_UNPACK_WITH_CALL
.3.6 新版功能.
-
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 argument objects in positional order0x02
a dictionary of keyword-only parameters' default values0x04
an annotation dictionary0x08
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 theslice()
built-in function for more information.
-
EXTENDED_ARG
(ext)¶ Prefixes any opcode which has an argument too big to fit into the default two bytes. ext holds two additional bytes which, taken together with the subsequent opcode's argument, comprise a four-byte argument, ext being the two most-significant bytes.
-
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
: callstr()
on value before formatting it.(flags & 0x03) == 0x02
: callrepr()
on value before formatting it.(flags & 0x03) == 0x03
: callascii()
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 新版功能.
-
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).在 3.6 版更改: Now every instruction has an argument, but opcodes
< HAVE_ARGUMENT
ignore it. Before, only opcodes>= HAVE_ARGUMENT
had an argument.
32.12.4. 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 have a constant parameter.
-
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.