bpo-46541: Replace core use of _Py_IDENTIFIER() with statically initialized global objects. (gh-30928)

We're no longer using _Py_IDENTIFIER() (or _Py_static_string()) in any core CPython code.  It is still used in a number of non-builtin stdlib modules.

The replacement is: PyUnicodeObject (not pointer) fields under _PyRuntimeState, statically initialized as part of _PyRuntime.  A new _Py_GET_GLOBAL_IDENTIFIER() macro facilitates lookup of the fields (along with _Py_GET_GLOBAL_STRING() for non-identifier strings).

https://bugs.python.org/issue46541#msg411799 explains the rationale for this change.

The core of the change is in:

* (new) Include/internal/pycore_global_strings.h - the declarations for the global strings, along with the macros
* Include/internal/pycore_runtime_init.h - added the static initializers for the global strings
* Include/internal/pycore_global_objects.h - where the struct in pycore_global_strings.h is hooked into _PyRuntimeState
* Tools/scripts/generate_global_objects.py - added generation of the global string declarations and static initializers

I've also added a --check flag to generate_global_objects.py (along with make check-global-objects) to check for unused global strings.  That check is added to the PR CI config.

The remainder of this change updates the core code to use _Py_GET_GLOBAL_IDENTIFIER() instead of _Py_IDENTIFIER() and the related _Py*Id functions (likewise for _Py_GET_GLOBAL_STRING() instead of _Py_static_string()).  This includes adding a few functions where there wasn't already an alternative to _Py*Id(), replacing the _Py_Identifier * parameter with PyObject *.

The following are not changed (yet):

* stop using _Py_IDENTIFIER() in the stdlib modules
* (maybe) get rid of _Py_IDENTIFIER(), etc. entirely -- this may not be doable as at least one package on PyPI using this (private) API
* (maybe) intern the strings during runtime init

https://bugs.python.org/issue46541
This commit is contained in:
Eric Snow 2022-02-08 13:39:07 -07:00 committed by GitHub
parent c018d3037b
commit 81c72044a1
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GPG key ID: 4AEE18F83AFDEB23
108 changed files with 2282 additions and 1573 deletions

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@ -22,9 +22,6 @@ class int "PyObject *" "&PyLong_Type"
[clinic start generated code]*/
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=ec0275e3422a36e3]*/
_Py_IDENTIFIER(little);
_Py_IDENTIFIER(big);
/* Is this PyLong of size 1, 0 or -1? */
#define IS_MEDIUM_VALUE(x) (((size_t)Py_SIZE(x)) + 1U < 3U)
@ -5775,9 +5772,9 @@ int_to_bytes_impl(PyObject *self, Py_ssize_t length, PyObject *byteorder,
if (byteorder == NULL)
little_endian = 0;
else if (_PyUnicode_EqualToASCIIId(byteorder, &PyId_little))
else if (_PyUnicode_Equal(byteorder, &_Py_ID(little)))
little_endian = 1;
else if (_PyUnicode_EqualToASCIIId(byteorder, &PyId_big))
else if (_PyUnicode_Equal(byteorder, &_Py_ID(big)))
little_endian = 0;
else {
PyErr_SetString(PyExc_ValueError,
@ -5837,9 +5834,9 @@ int_from_bytes_impl(PyTypeObject *type, PyObject *bytes_obj,
if (byteorder == NULL)
little_endian = 0;
else if (_PyUnicode_EqualToASCIIId(byteorder, &PyId_little))
else if (_PyUnicode_Equal(byteorder, &_Py_ID(little)))
little_endian = 1;
else if (_PyUnicode_EqualToASCIIId(byteorder, &PyId_big))
else if (_PyUnicode_Equal(byteorder, &_Py_ID(big)))
little_endian = 0;
else {
PyErr_SetString(PyExc_ValueError,