Extract common bytecode retrieval logic from `_PyFrame_GetBytecode` and `_PyFrame_SafeGetLasti`
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Description
Both _PyFrame_GetBytecode and _PyFrame_SafeGetLasti inline functions currently duplicate the same logic for retrieving the bytecode, differing only in whether they call _PyFrame_GetCode or _PyFrame_SafeGetCode.
static inline _Py_CODEUNIT *
_PyFrame_GetBytecode(_PyInterpreterFrame *f)
{
#ifdef Py_GIL_DISABLED
PyCodeObject *co = _PyFrame_GetCode(f);
_PyCodeArray *tlbc = _PyCode_GetTLBCArray(co);
assert(f->tlbc_index >= 0 && f->tlbc_index < tlbc->size);
return (_Py_CODEUNIT *)tlbc->entries[f->tlbc_index];
#else
return _PyCode_CODE(_PyFrame_GetCode(f));
#endif
}
static inline int
_PyFrame_SafeGetLasti(struct _PyInterpreterFrame *f)
{
// Code based on _PyFrame_GetBytecode() but replace _PyFrame_GetCode()
// with _PyFrame_SafeGetCode().
PyCodeObject *co = _PyFrame_SafeGetCode(f);
if (co == NULL) {
return -1;
}
_Py_CODEUNIT *bytecode;
#ifdef Py_GIL_DISABLED
_PyCodeArray *tlbc = _PyCode_GetTLBCArray(co);
assert(f->tlbc_index >= 0 && f->tlbc_index < tlbc->size);
bytecode = (_Py_CODEUNIT *)tlbc->entries[f->tlbc_index];
#else
bytecode = _PyCode_CODE(co);
#endif
return (int)(f->instr_ptr - bytecode) * sizeof(_Py_CODEUNIT);
}
However, I think we should extract the bytecode retrieving logic into another helper, let's say, _PyFrame_GetBytecodeFromCodeObject, as:
static inline _Py_CODEUNIT *
_PyFrame_GetBytecodeFromCodeObject(_PyInterpreterFrame *f, PyCodeObject *co)
{
#ifdef Py_GIL_DISABLED
_PyCodeArray *tlbc = _PyCode_GetTLBCArray(co);
assert(f->tlbc_index >= 0 && f->tlbc_index < tlbc->size);
return (_Py_CODEUNIT *)tlbc->entries[f->tlbc_index];
#else
return _PyCode_CODE(co);
#endif
}
So we can use that helper as:
static inline _Py_CODEUNIT *
_PyFrame_GetBytecode(_PyInterpreterFrame *f)
{
PyCodeObject *co = _PyFrame_GetCode(f);
return _PyFrame_GetBytecodeFromCodeObject(f, co);
}
static inline int
_PyFrame_SafeGetLasti(_PyInterpreterFrame *f)
{
PyCodeObject *co = _PyFrame_SafGetCode(f);
if(co == NULL){
return -1;
}
_Py_CODEUNIT *bytecode = _PyFrame_GetBytecodeFromCodeObject(f, co);
return (int)(f->insert_ptr - bytecode) * sizeof(_Py_CODEUNIT);
}
However, we can use different types of helpers such as inline helper with a function pointer or a macro wrapper. My point here is not about the implementation of the helper itself, but about extracting the bytecode retrieving logic into another helper regardless of the helper name and the method used to implement that helper.
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First steps
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- Open a pull request that references the issue number.
Research direction
Start by locating _PyFrame_GetBytecode and _PyFrame_SafeGetLasti, then compare their callers and the existing _PyFrame_GetCode and _PyFrame_SafeGetCode paths. Extract their shared bytecode retrieval logic while preserving both GIL-enabled and GIL-disabled behavior, and verify that the relevant CPython tests pass.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- c
- Domain
- backend
- Issue type
- Refactor
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100