Question

这是我的代码：

x=100
def foo(m, n=66):
    return m + n  

b=200
a=foo(x) + b
print(a)

这是反汇编的：

$ python3 -m dis test_func.py
  1           0 LOAD_CONST               0 (100)
              2 STORE_NAME               0 (x)

  2           4 LOAD_CONST               6 ((66,))
              6 LOAD_CONST               2 (<code object foo at 0x7f2c7dba39c0, file "test_func.py", line 2>)
              8 LOAD_CONST               3 ('foo')
             10 MAKE_FUNCTION            1
             12 STORE_NAME               1 (foo)

  5          14 LOAD_CONST               4 (200)
             16 STORE_NAME               2 (b)

  6          18 LOAD_NAME                1 (foo)
             20 LOAD_NAME                0 (x)
             22 CALL_FUNCTION            1
             24 LOAD_NAME                2 (b)
             26 BINARY_ADD
             28 STORE_NAME               3 (a)

  7          30 LOAD_NAME                4 (print)
             32 LOAD_NAME                3 (a)
             34 CALL_FUNCTION            1
             36 POP_TOP
             38 LOAD_CONST               5 (None)
             40 RETURN_VALUE

我的问题围绕这一部分：

  2           4 LOAD_CONST               6 ((66,))
              6 LOAD_CONST               2 (<code object foo at 0x7f2c7dba39c0, file "test_func.py", line 2>)
              8 LOAD_CONST               3 ('foo')
             10 MAKE_FUNCTION            1

以下是document中有关MAKE_FUNCTION的摘录：

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)

我很难解释这些标志：我在反汇编中看不到任何标志。

所以让我们将反汇编与doc相关联，当它运行到MAKE_FUNCTION时，堆栈深度为3：

1. the top is "foo" which comes from instruction @8
2. the next one is code object which comes from instruction @6
3. the bottom one is 66 which comes from instruction @4

现在我的问题是，该字节码中的“标志”在哪里？我的意思是文档中提到的0x01、0x02、0x04和/或0x08。 @ 4指令中的那个“ 6”吗？但是6是2和4，而这里只是位置参数……

请帮忙。

谢谢！

Answer 1

标志是MAKE_FUNCTION指令的参数：

         10 MAKE_FUNCTION            1

标志为1，即0x01。

Python 3.7字节码MAKE_FUNCTION：如何解释这种反汇编的函数声明？

1 个答案: