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, 3 insertions, 3 deletions

diff --git a/Objects/genobject.c b/Objects/genobject.c
index 885b3f2..7c2948b 100644
--- a/Objects/genobject.c
+++ b/Objects/genobject.c
@@ -151,7 +151,7 @@ gen_dealloc(PyGenObject *gen)
 static PyObject *
 gen_send_ex(PyGenObject *gen, PyObject *arg, int exc, int closing)
 {
-    PyThreadState *tstate = PyThreadState_GET();
+    PyThreadState *tstate = _PyThreadState_GET();
     PyFrameObject *f = gen->gi_frame;
     PyObject *result;
 
@@ -1157,7 +1157,7 @@ PyCoro_New(PyFrameObject *f, PyObject *name, PyObject *qualname)
         return NULL;
     }
 
-    PyThreadState *tstate = PyThreadState_GET();
+    PyThreadState *tstate = _PyThreadState_GET();
     int origin_depth = tstate->coroutine_origin_tracking_depth;
 
     if (origin_depth == 0) {
@@ -1267,7 +1267,7 @@ async_gen_init_hooks(PyAsyncGenObject *o)
 
     o->ag_hooks_inited = 1;
 
-    tstate = PyThreadState_GET();
+    tstate = _PyThreadState_GET();
 
     finalizer = tstate->async_gen_finalizer;
     if (finalizer) {