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Use a correct and transparent definition of "code unit" in C code #100222
Description
We should define _Py_CODEUNIT properly without the need for type punning.
Currently _Py_CODEUNIT is define as typedef uint16_t _Py_CODEUNIT; but it really an 8 bit opcode followed a bit operand aligned to 16 bits. Which means we need to resort to type punning to access the operand and oparg individually.
E.g. https://github.com/python/cpython/blob/main/Include/cpython/code.h#L32
PEP 7 states that "Python 3.11 and newer versions use C11 without optional_features".
So let's use a union with anonymous struct to define it properly:
typedef union {
int16_t align;
struct {
uint8_t opcode;
uint8_t oparg;
};
} _Py_CODEUNIT;@iritkatriel thoughts?
Activity
iritkatriel commentedon Dec 13, 2022
Looks good, would it be a drop-in replacement?
markshannon commentedon Dec 13, 2022
Depends on how you define "drop-in"
GH-100222: Redefine _Py_CODEUNIT as a union to clarify structure of c…
Merge branch 'main' into typedocs
GH-100222: fix typo _py_set_opocde -> _py_set_opcode (GH-100259)
Merge branch 'main' into fastmock