dis庫(kù)是python(默認(rèn)的CPython)自帶的一個(gè)庫(kù),可以用來(lái)分析字節(jié)碼

例子

首先導(dǎo)入dis庫(kù)

>>> import dis

然后在repl中,創(chuàng)建一個(gè)函數(shù)

>>> def add(a, b = 0):
...     return a + b
... 
>>> 

最后將add函數(shù)傳給dis庫(kù)的dis函數(shù)

>>> dis.dis(add)
  2           0 LOAD_FAST                0 (a)
              2 LOAD_FAST                1 (b)
              4 BINARY_ADD
              6 RETURN_VALUE
>>> 

repl會(huì)返回add函數(shù)的字節(jié)碼.

分析

來(lái)看看dis函數(shù)的源碼

def dis(x=None, *, file=None):
    """Disassemble classes, methods, functions, generators, or code.
    With no argument, disassemble the last traceback.
    """
    if x is None:
        distb(file=file)
        return
    if hasattr(x, '__func__'):  # Method
        x = x.__func__
    if hasattr(x, '__code__'):  # Function
        x = x.__code__
    if hasattr(x, 'gi_code'):  # Generator
        x = x.gi_code
    if hasattr(x, '__dict__'):  # Class or module
        items = sorted(x.__dict__.items())
        for name, x1 in items:
            if isinstance(x1, _have_code):
                print("Disassembly of %s:" % name, file=file)
                try:
                    dis(x1, file=file)
                except TypeError as msg:
                    print("Sorry:", msg, file=file)
                print(file=file)
    elif hasattr(x, 'co_code'): # Code object
        disassemble(x, file=file)
    elif isinstance(x, (bytes, bytearray)): # Raw bytecode
        _disassemble_bytes(x, file=file)
    elif isinstance(x, str):    # Source code
        _disassemble_str(x, file=file)
    else:
        raise TypeError("don't know how to disassemble %s objects" %
                        type(x).__name__)

x參數(shù)可以是None、Method、Function、Generator、Class、module、Code object、Raw bytecode、Source code,如果x是Method、Function、Generator,只用返回對(duì)應(yīng)的字節(jié)碼,
如果x是Class或者module,那會(huì)返回x的所有元素(先排序)的字節(jié)碼,這一句代碼x.dict.items()有提現(xiàn).如果x是Code object或者Raw bytecode,或者Source code,那么會(huì)調(diào)用對(duì)應(yīng)的disassemble函數(shù). disassemble函數(shù)是干嘛的呢,顧名思義,就是assemble的反義詞, assemble是匯編的意思,那disassemble自然是有一個(gè) 反匯編 的意思,當(dāng)然這里并不是真的反匯編,而是只是輸出字節(jié)碼.

disassemble的函數(shù)細(xì)節(jié)可以自己去看看源碼,源碼也在dis.py里

源碼

https://github.com/python/cpython/blob/3.6/Lib/dis.py