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/Parser/myreadline.c b/Parser/myreadline.c
index d18cf1b..f511319 100644
--- a/Parser/myreadline.c
+++ b/Parser/myreadline.c
@@ -301,7 +301,7 @@ PyOS_Readline(FILE *sys_stdin, FILE *sys_stdout, const char *prompt)
     char *rv, *res;
     size_t len;
 
-    if (_PyOS_ReadlineTState == PyThreadState_GET()) {
+    if (_PyOS_ReadlineTState == _PyThreadState_GET()) {
         PyErr_SetString(PyExc_RuntimeError,
                         "can't re-enter readline");
         return NULL;
@@ -316,7 +316,7 @@ PyOS_Readline(FILE *sys_stdin, FILE *sys_stdout, const char *prompt)
         _PyOS_ReadlineLock = PyThread_allocate_lock();
     }
 
-    _PyOS_ReadlineTState = PyThreadState_GET();
+    _PyOS_ReadlineTState = _PyThreadState_GET();
     Py_BEGIN_ALLOW_THREADS
     PyThread_acquire_lock(_PyOS_ReadlineLock, 1);