In GH-2866, _Py_Bit_Length() was added to pymath.h for lack of a better
location. GH-20518 added a more appropriate header file for bit utilities. It
also shows how to properly use intrinsics. This allows reconsidering bpo-29782.
* Move the function to the new header.
* Changed return type to match __builtin_clzl() and reviewed usage.
* Use intrinsics where available.
* Pick a fallback implementation suitable for inlining.
* Rename pycore_byteswap.h to pycore_bitutils.h.
* Move popcount_digit() to pycore_bitutils.h as _Py_popcount32().
* _Py_popcount32() uses GCC and clang builtin function if available.
* Add unit tests to _Py_popcount32().
Add a new internal pycore_byteswap.h header file with the following
functions:
* _Py_bswap16()
* _Py_bswap32()
* _Py_bswap64()
Use these functions in _ctypes, sha256 and sha512 modules,
and also use in the UTF-32 encoder.
sha256, sha512 and _ctypes modules are now built with the internal
C API.
Move the PyGC_Head structure and the following private macros to the
internal C API:
* _PyGCHead_FINALIZED()
* _PyGCHead_NEXT()
* _PyGCHead_PREV()
* _PyGCHead_SET_FINALIZED()
* _PyGCHead_SET_NEXT()
* _PyGCHead_SET_PREV()
* _PyGC_FINALIZED()
* _PyGC_PREV_MASK
* _PyGC_PREV_MASK_COLLECTING
* _PyGC_PREV_MASK_FINALIZED
* _PyGC_PREV_SHIFT
* _PyGC_SET_FINALIZED()
* _PyObject_GC_IS_TRACKED()
* _PyObject_GC_MAY_BE_TRACKED()
* _Py_AS_GC(o)
Keep the private _PyGC_FINALIZED() macro in the public C API for
backward compatibility with Python 3.8: make it an alias to the new
PyObject_GC_IsFinalized() function.
Move the SIZEOF_PYGC_HEAD constant from _testcapi module to
_testinternalcapi module.
Add a new _testinternalcapi module to test the internal C API.
Move _Py_GetConfigsAsDict() function to the internal C API:
_testembed now uses _testinternalcapi to access the function.
Victor Stinner
Steve Dower
Christian Heimes
Niklas Fiekas
Hai Shi
Victor Stinner