pythongh-117139: Replace _PyList_FromArraySteal with stack ref variant (

python#122830)

This replaces `_PyList_FromArraySteal` with `_PyList_FromStackRefSteal`.
It's functionally equivalent, but takes a `_PyStackRef` array instead of
an array of `PyObject` pointers.

Co-authored-by: Ken Jin <kenjin@python.org>

Include/internal/pycore_list.h

@@ -56,7 +56,10 @@ typedef struct {
     PyListObject *it_seq; /* Set to NULL when iterator is exhausted */
 } _PyListIterObject;
 
-PyAPI_FUNC(PyObject *)_PyList_FromArraySteal(PyObject *const *src, Py_ssize_t n);
+union _PyStackRef;
+
+PyAPI_FUNC(PyObject *)_PyList_FromStackRefSteal(const union _PyStackRef *src, Py_ssize_t n);
+
 
 #ifdef __cplusplus
 }

Objects/listobject.c

@@ -3142,7 +3142,7 @@ PyList_AsTuple(PyObject *v)
 }
 
 PyObject *
-_PyList_FromArraySteal(PyObject *const *src, Py_ssize_t n)
+_PyList_FromStackRefSteal(const _PyStackRef *src, Py_ssize_t n)
 {
     if (n == 0) {
         return PyList_New(0);
@@ -3151,13 +3151,15 @@ _PyList_FromArraySteal(PyObject *const *src, Py_ssize_t n)
     PyListObject *list = (PyListObject *)PyList_New(n);
     if (list == NULL) {
         for (Py_ssize_t i = 0; i < n; i++) {
-            Py_DECREF(src[i]);
+            PyStackRef_CLOSE(src[i]);
         }
         return NULL;
     }
 
     PyObject **dst = list->ob_item;
-    memcpy(dst, src, n * sizeof(PyObject *));
+    for (Py_ssize_t i = 0; i < n; i++) {
+        dst[i] = PyStackRef_AsPyObjectSteal(src[i]);
+    }
 
     return (PyObject *)list;
 }

Python/bytecodes.c

@@ -1666,13 +1666,7 @@ dummy_func(
         }
 
         inst(BUILD_LIST, (values[oparg] -- list)) {
-            STACKREFS_TO_PYOBJECTS(values, oparg, values_o);
-            if (CONVERSION_FAILED(values_o)) {
-                DECREF_INPUTS();
-                ERROR_IF(true, error);
-            }
-            PyObject *list_o = _PyList_FromArraySteal(values_o, oparg);
-            STACKREFS_TO_PYOBJECTS_CLEANUP(values_o);
+            PyObject *list_o = _PyList_FromStackRefSteal(values, oparg);
             ERROR_IF(list_o == NULL, error);
             list = PyStackRef_FromPyObjectSteal(list_o);
         }

Tools/cases_generator/analyzer.py

@@ -534,7 +534,7 @@ def has_error_without_pop(op: parser.InstDef) -> bool:
     "STACKREFS_TO_PYOBJECTS",
     "STACKREFS_TO_PYOBJECTS_CLEANUP",
     "CONVERSION_FAILED",
-    "_PyList_FromArraySteal",
+    "_PyList_FromStackRefSteal",
     "_PyTuple_FromArraySteal",
     "_PyTuple_FromStackRefSteal",
 )