dis
— Python 字节码的反汇编程序
¶
源代码： Lib/dis.py
The
dis
模块支持分析 CPython
bytecode
通过反汇编它。此模块接受作为输入的 CPython 字节码的定义在文件
Include/opcode.h
并用于编译器和解释器。
CPython 实现细节： 字节码是 CPython 解释器的实现细节。不保证字节码不会在 Python 版本之间被添加、移除或改变。不应考虑使用此模块来跨 Python VM 或 Python 发行。
范例：给定函数
myfunc()
:
def myfunc(alist): return len(alist)
以下命令可以用于显示反汇编的
myfunc()
:
>>> dis.dis(myfunc) 2 0 LOAD_GLOBAL 0 (len) 3 LOAD_FAST 0 (alist) 6 CALL_FUNCTION 1 9 RETURN_VALUE
(2 是行号)。
3.4 版新增。
字节码分析 API 允许将 Python 代码片段包裹在
Bytecode
对象，以提供对编译代码的详细轻松访问。
dis.
Bytecode
(
x
,
*
,
first_line=None
,
current_offset=None
)
¶
Analyse the bytecode corresponding to a function, 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
实例。
若 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.
若
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.
from_traceback
(
tb
)
¶
构造
Bytecode
instance from the given traceback, setting
current_offset
to the instruction responsible for the exception.
codeobj
¶
编译代码对象。
first_line
¶
代码对象的第 1 源行 (若可用)
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()
.
范例：
>>> bytecode = dis.Bytecode(myfunc) >>> for instr in bytecode: ... print(instr.opname) ... LOAD_GLOBAL LOAD_FAST CALL_FUNCTION RETURN_VALUE
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, 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 版新增。
dis.
show_code
(
x
,
*
,
file=None
)
¶
Print detailed code object information for the supplied function, method, source code string or code object to
file
(或
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 版新增。
3.4 版改变： 添加 file 参数。
dis.
dis
(
x=None
,
*
,
file=None
)
¶
反汇编
x
对象。
x
can denote either a module, a class, a method, a function, a code object, a string of source code or a byte sequence of raw bytecode. For a module, it disassembles all functions. For a class, it disassembles all methods. For a code object or sequence of raw bytecode, it prints one line per bytecode instruction. Strings are first compiled to code objects with the
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
否则。
3.4 版改变： 添加 file 参数。
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
否则。
3.4 版改变： 添加 file 参数。
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 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
否则。
3.4 版改变： 添加 file 参数。
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.
若 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 版新增。
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.
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 采用自变量 oparg .
3.4 版新增。
The
get_instructions()
函数和
Bytecode
class provide details of bytecode instructions as
Instruction
实例：
dis.
Instruction
¶
用于字节码操作的细节
opcode
¶
numeric code for operation, corresponding to the opcode values listed below and the bytecode values in the 操作码集合 .
opname
¶
人性化可读操作的名称
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 版新增。
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.
DUP_TOP_TWO
¶
Duplicates the two references on top of the stack, leaving them in the same order.
Unary operations
Unary operations take the top of the stack, apply the operation, and push the result back on the stack.
UNARY_POSITIVE
¶
实现
TOS = +TOS
.
UNARY_NEGATIVE
¶
实现
TOS = -TOS
.
UNARY_NOT
¶
实现
TOS = not TOS
.
UNARY_INVERT
¶
实现
TOS = ~TOS
.
GET_ITER
¶
实现
TOS = iter(TOS)
.
Binary operations
Binary operations remove the top of the stack (TOS) and the second top-most stack item (TOS1) from the stack. They perform the operation, and put the result back on the stack.
BINARY_POWER
¶
实现
TOS = TOS1 ** TOS
.
BINARY_MULTIPLY
¶
实现
TOS = TOS1 * TOS
.
BINARY_FLOOR_DIVIDE
¶
实现
TOS = TOS1 // TOS
.
BINARY_TRUE_DIVIDE
¶
实现
TOS = TOS1 / TOS
.
BINARY_MODULO
¶
实现
TOS = TOS1 % TOS
.
BINARY_ADD
¶
实现
TOS = TOS1 + TOS
.
BINARY_SUBTRACT
¶
实现
TOS = TOS1 - TOS
.
BINARY_SUBSCR
¶
实现
TOS = TOS1[TOS]
.
BINARY_LSHIFT
¶
实现
TOS = TOS1 << TOS
.
BINARY_RSHIFT
¶
实现
TOS = TOS1 >> TOS
.
BINARY_AND
¶
实现
TOS = TOS1 & TOS
.
BINARY_XOR
¶
实现
TOS = TOS1 ^ TOS
.
BINARY_OR
¶
实现
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_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
¶
实现
TOS1[TOS] = TOS2
.
DELETE_SUBSCR
¶
实现
del TOS1[TOS]
.
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
语句。
target
is the address to jump to (which should be a
FOR_ITER
instruction).
SET_ADD
(
i
)
¶
调用
set.add(TOS1[-i], TOS)
. Used to implement set comprehensions.
LIST_APPEND
(
i
)
¶
调用
list.append(TOS[-i], TOS)
. Used to implement list comprehensions.
MAP_ADD
(
i
)
¶
调用
dict.setitem(TOS1[-i], TOS, TOS1)
. Used to implement dict comprehensions.
For all of the
SET_ADD
,
LIST_APPEND
and
MAP_ADD
instructions, while the added value or key/value pair is popped off, the container object remains on the stack so that it is available for further iterations of the loop.
RETURN_VALUE
¶
Returns with TOS to the caller of the function.
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
¶
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 by
CALL_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 by
WITH_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
，或
UNPACK_SEQUENCE
).
WITH_CLEANUP
¶
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:
None
WHY_{RETURN,CONTINUE}
), retval
WHY_*
; no retval below it
In the last case,
TOS(SECOND, THIRD, FOURTH)
被调用，否则
TOS(None, None, None)
. In addition, TOS is removed from the stack.
If the stack represents an exception,
and
the function call returns a ‘true’ value, this information is “zapped” and replaced with a single
WHY_SILENCED
to prevent
END_FINALLY
from re-raising the exception. (But non-local gotos will still be resumed.)
All of the following opcodes expect arguments. An argument is two bytes, with the more significant byte last.
STORE_NAME
(
namei
)
¶
实现
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
若可能的话。
DELETE_NAME
(
namei
)
¶
实现
del name
，其中
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 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
)
¶
实现
TOS.name = TOS1
，其中
namei
is the index of name in
co_names
.
DELETE_ATTR
(
namei
)
¶
实现
del TOS.name
，使用
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]
在堆栈。
LOAD_NAME
(
namei
)
¶
Pushes the value associated with
co_names[namei]
在堆栈。
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. The dictionary is pre-sized to hold count 条目。
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.
POP_JUMP_IF_FALSE
(
target
)
¶
If TOS is false, sets the bytecode counter to target . TOS is popped.
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.
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.
JUMP_ABSOLUTE
(
target
)
¶
将字节码计数器设为 target .
FOR_ITER
(
delta
)
¶
TOS 是
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]
在堆栈。
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 字节。
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.
STORE_MAP
¶
Store a key and value pair in a dictionary. Pops the key and value while leaving the dictionary on the stack.
LOAD_FAST
(
var_num
)
¶
将引用压入本地
co_varnames[var_num]
在堆栈。
STORE_FAST
(
var_num
)
¶
将 TOS 存储到本地
co_varnames[var_num]
.
DELETE_FAST
(
var_num
)
¶
删除本地
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.
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
语句。
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. The low byte of argc indicates the number of positional parameters, the high byte the number of keyword parameters. On the stack, the opcode finds the keyword parameters first. For each keyword argument, the value is on top of the key. Below the keyword parameters, the positional parameters are on the stack, with the right-most parameter on top. Below the parameters, the function object to call is on the stack. Pops all function arguments, and the function itself off the stack, and pushes the return value.
MAKE_FUNCTION
(
argc
)
¶
Pushes a new function object on the stack. From bottom to top, the consumed stack must consist of
argc & 0xFF
default argument objects in positional order
(argc >> 8) & 0xFF
pairs of name and default argument, with the name
just below the object on the stack, for keyword-only parameters
(argc >> 16) & 0x7FFF
parameter annotation objects
MAKE_CLOSURE
(
argc
)
¶
Creates a new function object, sets its
__closure__
slot, and pushes it on the stack. TOS is the
合格名称
of the function, TOS1 is the code associated with the function, and TOS2 is the tuple containing cells for the closure’s free variables.
argc
is interpreted as in
MAKE_FUNCTION
; the annotations and defaults are also in the same order below TOS2.
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
)
¶
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.
CALL_FUNCTION_VAR
(
argc
)
¶
Calls a function.
argc
is interpreted as in
CALL_FUNCTION
. The top element on the stack contains the variable argument list, followed by keyword and positional arguments.
CALL_FUNCTION_KW
(
argc
)
¶
Calls a function.
argc
is interpreted as in
CALL_FUNCTION
. The top element on the stack contains the keyword arguments dictionary, followed by explicit keyword and positional arguments.
CALL_FUNCTION_VAR_KW
(
argc
)
¶
Calls a function.
argc
is interpreted as in
CALL_FUNCTION
. The top element on the stack contains the keyword arguments dictionary, followed by the variable-arguments tuple, followed by explicit keyword and positional arguments.
HAVE_ARGUMENT
¶
This is not really an opcode. It identifies the dividing line between opcodes which don’t take arguments
< HAVE_ARGUMENT
and those which do
>= HAVE_ARGUMENT
.
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.