Question

CPython解释器会自动将Python模块编译为.pyc文件。包含字节码的.pyc文件是二进制格式（封送代码？）。是否有GUI（或命令行）工具让我查看字节码？

Answer 1

每个* .pyc文件都是包含下一步的二进制文件：

一个四字节的幻数 - 它只是随着编组码的每次更改而改变的字节;
一个四字节的修改时间戳 - 是生成.pyc的源文件的Unix修改时间戳，以便在源更改时可以重新编译它;
因为版本Python3.3 +接下来的四个字节是将源文件的大小编码为long的字段;
编组的代码对象。

为什么不直接使用CPython的内置功能来完成这项任务呢？

文件view_pyc_file.py

import platform
import time
import sys
import binascii
import marshal
import dis
import struct


def view_pyc_file(path):
    """Read and display a content of the Python`s bytecode in a pyc-file."""

    file = open(path, 'rb')

    magic = file.read(4)
    timestamp = file.read(4)
    size = None

    if sys.version_info.major == 3 and sys.version_info.minor >= 3:
        size = file.read(4)
        size = struct.unpack('I', size)[0]

    code = marshal.load(file)

    magic = binascii.hexlify(magic).decode('utf-8')
    timestamp = time.asctime(time.localtime(struct.unpack('I', b'D\xa5\xc2X')[0]))

    dis.disassemble(code)

    print('-' * 80)
    print(
        'Python version: {}\nMagic code: {}\nTimestamp: {}\nSize: {}'
        .format(platform.python_version(), magic, timestamp, size)
    )

    file.close()


if __name__ == '__main__':
    view_pyc_file(sys.argv[1])

使用下一代CPython版本进行测试：

2.7.9
3.4.2
3.5.2

示范

文件内容main.py

$ cat main.py
print("Never give up")

通过python2.7创建并读取pyc文件

setivolkylany$~/Downloads/temp/temp$ python2.7 -m py_compile main.py 
setivolkylany$~/Downloads/temp/temp$ python2.7 view_pyc_file.py ./main.pyc
  1           0 LOAD_CONST               0 ('Never give up')
              3 PRINT_ITEM          
              4 PRINT_NEWLINE       
              5 LOAD_CONST               1 (None)
              8 RETURN_VALUE        
--------------------------------------------------------------------------------
Python version: 2.7.9
Magic code: 03f30d0a
Timestamp: Fri Mar 10 15:08:20 2017
Size: None

通过python3.4创建并读取pyc文件

setivolkylany$~/Downloads/temp/temp$ python3.4 -m py_compile main.py 
setivolkylany$~/Downloads/temp/temp$ python3.4 view_pyc_file.py __pycache__/main.cpython-34.pyc 
  1           0 LOAD_NAME                0 (print)
              3 LOAD_CONST               0 ('Never give up')
              6 CALL_FUNCTION            1 (1 positional, 0 keyword pair)
              9 POP_TOP
             10 LOAD_CONST               1 (None)
             13 RETURN_VALUE
--------------------------------------------------------------------------------
Python version: 3.4.2
Magic code: ee0c0d0a
Timestamp: Fri Mar 10 15:08:20 2017
Size: 23

通过python3.5创建并读取pyc文件

setivolkylany$~/Downloads/temp/temp$ python3.5 -m py_compile main.py 
setivolkylany$~/Downloads/temp/temp$ python3.5 view_pyc_file.py __pycache__/main.cpython-35.pyc 
  1           0 LOAD_NAME                0 (print)
              3 LOAD_CONST               0 ('Never give up')
              6 CALL_FUNCTION            1 (1 positional, 0 keyword pair)
              9 POP_TOP
             10 LOAD_CONST               1 (None)
             13 RETURN_VALUE
--------------------------------------------------------------------------------
Python version: 3.5.2
Magic code: 160d0d0a
Timestamp: Fri Mar 10 15:08:20 2017
Size: 23

基于：

Answer 2

有一个名为PyChrisanthemum的可视化python反汇编程序。

要以命令行方式执行此操作，您可以使用模块dis（python 2.7.3，python 3.2.3），因为OP已经找到了。

Answer 3

根据@Apteryx 关于 PEP 的注释扩展@PADYMKO 的代码形式：

def view_pyc_file(path):
    """Read and display a content of the Python`s bytecode in a pyc-file."""

    file = open(path, 'rb')

    magic = file.read(4)
    bit_field = None
    timestamp = None
    hashstr = None
    size = None

    if sys.version_info.major == 3 and sys.version_info.minor >=7:
        bit_field = int.from_bytes(file.read(4), byteorder=sys.byteorder)
        if 1 & bit_field == 1:
            hashstr = file.read(8)
        else:
            timestamp = file.read(4)
            size = file.read(4)
            size = struct.unpack('I', size)[0]
    elif sys.version_info.major == 3 and sys.version_info.minor >= 3:
        timestamp = file.read(4)
        size = file.read(4)
        size = struct.unpack('I', size)[0]
    else:
        timestamp = file.read(4)

    code = marshal.load(file)

    magic = binascii.hexlify(magic).decode('utf-8')
    timestamp = time.asctime(time.localtime(struct.unpack('I', b'D\xa5\xc2X')[0]))

    dis.disassemble(code)

    print('-' * 80)
    print(
        'Python version: {}\nMagic code: {}\nTimestamp: {}\nSize: {}\nHash: {}\nBitfield: {}'
        .format(platform.python_version(), magic, timestamp, size, hashstr, bit_field)
    )

    file.close()

给定一个python .pyc文件，是否有一个工具可以让我查看字节码？

3 个答案:

示范