gh-118335: Configure Tier 2 interpreter at build time (#118339)

The code for Tier 2 is now only compiled when configured
with `--enable-experimental-jit[=yes|interpreter]`.

We drop support for `PYTHON_UOPS` and -`Xuops`,
but you can disable the interpreter or JIT
at runtime by setting `PYTHON_JIT=0`.
You can also build it without enabling it by default
using `--enable-experimental-jit=yes-off`;
enable with `PYTHON_JIT=1`.

On Windows, the `build.bat` script supports
`--experimental-jit`, `--experimental-jit-off`,
`--experimental-interpreter`.

In the C code, `_Py_JIT` is defined as before
when the JIT is enabled; the new variable
`_Py_TIER2` is defined when the JIT *or* the
interpreter is enabled. It is actually a bitmask:
1: JIT; 2: default-off; 4: interpreter.

2 files changed, 18 insertions, 1 deletions

diff --git a/Modules/_opcode.c b/Modules/_opcode.c
index 5350adb..85e0ffe 100644
--- a/Modules/_opcode.c
+++ b/Modules/_opcode.c
@@ -367,7 +367,13 @@ _opcode_get_executor_impl(PyObject *module, PyObject *code, int offset)
                      Py_TYPE(code)->tp_name);
         return NULL;
     }
+#ifdef _Py_TIER2
     return (PyObject *)PyUnstable_GetExecutor((PyCodeObject *)code, offset);
+#else
+    PyErr_Format(PyExc_RuntimeError,
+                 "Executors are not available in this build");
+    return NULL;
+#endif
 }
 
 static PyMethodDef
diff --git a/Modules/_testinternalcapi.c b/Modules/_testinternalcapi.c
index 99e80ba..f7952a1 100644
--- a/Modules/_testinternalcapi.c
+++ b/Modules/_testinternalcapi.c
@@ -985,6 +985,8 @@ get_co_framesize(PyObject *self, PyObject *arg)
     return PyLong_FromLong(code->co_framesize);
 }
 
+#ifdef _Py_TIER2
+
 static PyObject *
 new_counter_optimizer(PyObject *self, PyObject *arg)
 {
@@ -1012,7 +1014,10 @@ set_optimizer(PyObject *self, PyObject *opt)
 static PyObject *
 get_optimizer(PyObject *self, PyObject *Py_UNUSED(ignored))
 {
-    PyObject *opt = (PyObject *)PyUnstable_GetOptimizer();
+    PyObject *opt = NULL;
+#ifdef _Py_TIER2
+    opt = (PyObject *)PyUnstable_GetOptimizer();
+#endif
     if (opt == NULL) {
         Py_RETURN_NONE;
     }
@@ -1045,6 +1050,8 @@ invalidate_executors(PyObject *self, PyObject *obj)
     Py_RETURN_NONE;
 }
 
+#endif
+
 static int _pending_callback(void *arg)
 {
     /* we assume the argument is callable object to which we own a reference */
@@ -2020,12 +2027,14 @@ static PyMethodDef module_functions[] = {
     {"iframe_getline", iframe_getline, METH_O, NULL},
     {"iframe_getlasti", iframe_getlasti, METH_O, NULL},
     {"get_co_framesize", get_co_framesize, METH_O, NULL},
+#ifdef _Py_TIER2
     {"get_optimizer", get_optimizer,  METH_NOARGS, NULL},
     {"set_optimizer", set_optimizer,  METH_O, NULL},
     {"new_counter_optimizer", new_counter_optimizer, METH_NOARGS, NULL},
     {"new_uop_optimizer", new_uop_optimizer, METH_NOARGS, NULL},
     {"add_executor_dependency", add_executor_dependency, METH_VARARGS, NULL},
     {"invalidate_executors", invalidate_executors, METH_O, NULL},
+#endif
     {"pending_threadfunc", _PyCFunction_CAST(pending_threadfunc),
      METH_VARARGS | METH_KEYWORDS},
     {"pending_identify", pending_identify, METH_VARARGS, NULL},
@@ -2072,7 +2081,9 @@ static PyMethodDef module_functions[] = {
     {"py_thread_id", get_py_thread_id, METH_NOARGS},
 #endif
     {"set_immortalize_deferred", set_immortalize_deferred, METH_VARARGS},
+#ifdef _Py_TIER2
     {"uop_symbols_test", _Py_uop_symbols_test, METH_NOARGS},
+#endif
     {NULL, NULL} /* sentinel */
 };