bpo-35081: Add _PyThreadState_GET() internal macro (GH-10266)

If Py_BUILD_CORE is defined, the PyThreadState_GET() macro access
_PyRuntime which comes from the internal pycore_state.h header.
Public headers must not require internal headers.

Move PyThreadState_GET() and _PyInterpreterState_GET_UNSAFE() from
Include/pystate.h to Include/internal/pycore_state.h, and rename
PyThreadState_GET() to _PyThreadState_GET() there.

The PyThreadState_GET() macro of pystate.h is now redefined when
pycore_state.h is included, to use the fast _PyThreadState_GET().

Changes:

* Add _PyThreadState_GET() macro
* Replace "PyThreadState_GET()->interp" with
  _PyInterpreterState_GET_UNSAFE()
* Replace PyThreadState_GET() with _PyThreadState_GET() in internal C
  files (compiled with Py_BUILD_CORE defined), but keep
  PyThreadState_GET() in the public header files.
* _testcapimodule.c: replace PyThreadState_GET() with
  PyThreadState_Get(); the module is not compiled with Py_BUILD_CORE
  defined.
* pycore_state.h now requires Py_BUILD_CORE to be defined.

1 files changed, 2 insertions, 2 deletions

diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 9a390b3e50..dedc4f7c87 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -1115,7 +1115,7 @@ subtype_dealloc(PyObject *self)
 {
     PyTypeObject *type, *base;
     destructor basedealloc;
-    PyThreadState *tstate = PyThreadState_GET();
+    PyThreadState *tstate = _PyThreadState_GET();
     int has_finalizer;
 
     /* Extract the type; we expect it to be a heap type */
@@ -7678,7 +7678,7 @@ super_init(PyObject *self, PyObject *args, PyObject *kwds)
         PyFrameObject *f;
         PyCodeObject *co;
         Py_ssize_t i, n;
-        f = PyThreadState_GET()->frame;
+        f = _PyThreadState_GET()->frame;
         if (f == NULL) {
             PyErr_SetString(PyExc_RuntimeError,
                             "super(): no current frame");