Implement _PyTuple_ExactDealloc

Author: reidenong

Include/internal/pycore_tuple.h

@@ -21,6 +21,8 @@ extern PyStatus _PyTuple_InitGlobalObjects(PyInterpreterState *);
 
 /* other API */
 
+PyAPI_FUNC(void) _PyTuple_ExactDealloc(PyObject *self);
+
 #define _PyTuple_ITEMS(op) _Py_RVALUE(_PyTuple_CAST(op)->ob_item)
 
 PyAPI_FUNC(PyObject *)_PyTuple_FromStackRefStealOnSuccess(const union _PyStackRef *, Py_ssize_t);

Include/internal/pycore_uop_metadata.h

@@ -205,6 +205,35 @@ PyTuple_Pack(Py_ssize_t n, ...)
 
 /* Methods */
 
+void
+_PyTuple_ExactDealloc(PyObject *obj)
+{
+    assert(PyTuple_CheckExact(obj));
+    PyTupleObject *op = _PyTuple_CAST(obj);
+
+    if (Py_SIZE(op) == 0 && op == &_Py_SINGLETON(tuple_empty)) {
+#ifdef Py_DEBUG
+        _Py_FatalRefcountError("deallocating the empty tuple singleton");
+#else
+        return;
+#endif
+    }
+
+    PyObject_GC_UnTrack(op);
+
+#ifdef Py_DEBUG
+    Py_ssize_t i = Py_SIZE(op);
+    while (--i >= 0) {
+        assert(op->ob_item[i] == NULL);
+    }
+#endif
+
+    // This will abort on the empty singleton (if there is one).
+    if (!maybe_freelist_push(op)) {
+        Py_TYPE(op)->tp_free((PyObject *)op);
+    }
+}
+
 static void
 tuple_dealloc(PyObject *self)
 {

Objects/tupleobject.c

@@ -30,7 +30,7 @@
 #include "pycore_sliceobject.h"   // _PyBuildSlice_ConsumeRefs
 #include "pycore_stackref.h"
 #include "pycore_template.h"      // _PyTemplate_Build()
-#include "pycore_tuple.h"         // _PyTuple_ITEMS()
+#include "pycore_tuple.h"         // _PyTuple_ExactDealloc(), _PyTuple_ITEMS()
 #include "pycore_typeobject.h"    // _PySuper_Lookup()
 
 #include "pycore_dict.h"
@@ -1682,7 +1682,7 @@ dummy_func(
                 *values++ = PyStackRef_FromPyObjectSteal(items[i]);
                 items[i] = NULL;
             }
-            DECREF_INPUTS();
+            PyStackRef_CLOSE_SPECIALIZED(seq, _PyTuple_ExactDealloc);
         }
 
         macro(UNPACK_SEQUENCE_LIST) =