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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@ -179,12 +179,10 @@ meth_dealloc(PyCFunctionObject *m)
static PyObject *
meth_reduce(PyCFunctionObject *m, PyObject *Py_UNUSED(ignored))
{
_Py_IDENTIFIER(getattr);
if (m->m_self == NULL || PyModule_Check(m->m_self))
return PyUnicode_FromString(m->m_ml->ml_name);
return Py_BuildValue("N(Os)", _PyEval_GetBuiltinId(&PyId_getattr),
return Py_BuildValue("N(Os)", _PyEval_GetBuiltin(&_Py_ID(getattr)),
m->m_self, m->m_ml->ml_name);
}
@ -223,14 +221,13 @@ meth_get__qualname__(PyCFunctionObject *m, void *closure)
Otherwise return type(m.__self__).__qualname__ + '.' + m.__name__
(e.g. [].append.__qualname__ == 'list.append') */
PyObject *type, *type_qualname, *res;
_Py_IDENTIFIER(__qualname__);
if (m->m_self == NULL || PyModule_Check(m->m_self))
return PyUnicode_FromString(m->m_ml->ml_name);
type = PyType_Check(m->m_self) ? m->m_self : (PyObject*)Py_TYPE(m->m_self);
type_qualname = _PyObject_GetAttrId(type, &PyId___qualname__);
type_qualname = PyObject_GetAttr(type, &_Py_ID(__qualname__));
if (type_qualname == NULL)
return NULL;