Delay destruction of trampoline code object and make symbol private

Author: markshannon

Python/ceval.c

@@ -1037,6 +1037,7 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
     py_frame.f_locals = NULL;
     py_frame.frame_obj = NULL;
     py_frame.f_code = tstate->interp->interpreter_trampoline;
+    assert(tstate->interp->interpreter_trampoline != NULL);
     py_frame.prev_instr = _PyCode_CODE(tstate->interp->interpreter_trampoline);
     py_frame.stacktop = 0;
     py_frame.owner = FRAME_OWNED_BY_CSTACK;

Python/pylifecycle.c

@@ -757,7 +757,7 @@ pycore_init_types(PyInterpreterState *interp)
     return _PyStatus_OK();
 }
 
-const char INTERPRETER_TRAMPOLINE_CODE[] = {
+static const char INTERPRETER_TRAMPOLINE_CODE[] = {
     0, 0,
     INTERPRETER_EXIT, 0,
     RESUME, 0

Python/pystate.c

@@ -425,7 +425,6 @@ interpreter_clear(PyInterpreterState *interp, PyThreadState *tstate)
     Py_CLEAR(interp->importlib);
     Py_CLEAR(interp->import_func);
     Py_CLEAR(interp->dict);
-    Py_CLEAR(interp->interpreter_trampoline);
 #ifdef HAVE_FORK
     Py_CLEAR(interp->before_forkers);
     Py_CLEAR(interp->after_forkers_parent);
@@ -451,6 +450,7 @@ interpreter_clear(PyInterpreterState *interp, PyThreadState *tstate)
     PyDict_Clear(interp->builtins);
     Py_CLEAR(interp->sysdict);
     Py_CLEAR(interp->builtins);
+    Py_CLEAR(interp->interpreter_trampoline);
 
     // XXX Once we have one allocator per interpreter (i.e.
     // per-interpreter GC) we must ensure that all of the interpreter's