gh-125323: Remove some unsafe Py_DECREFs in bytecodes.c, replacing th…

…em with PyStackRef_CLOSEs (GH-125324)
python · Oct 14, 2024 · 4b358ee · 4b358ee
1 parent b52c730
commit 4b358ee
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Showing 6 changed files with 65 additions and 60 deletions.
diff --git a/Include/internal/pycore_stackref.h b/Include/internal/pycore_stackref.h
@@ -153,6 +153,8 @@ PyStackRef_AsStrongReference(_PyStackRef stackref)
     return PyStackRef_FromPyObjectSteal(PyStackRef_AsPyObjectSteal(stackref));
 }
 
+#define PyStackRef_CLOSE_SPECIALIZED(stackref, dealloc) PyStackRef_CLOSE(stackref)
+
 
 #else // Py_GIL_DISABLED
 
@@ -177,6 +179,7 @@ static const _PyStackRef PyStackRef_NULL = { .bits = 0 };
 
 #define PyStackRef_DUP(stackref) PyStackRef_FromPyObjectSteal(Py_NewRef(PyStackRef_AsPyObjectBorrow(stackref)))
 
+#define PyStackRef_CLOSE_SPECIALIZED(stackref, dealloc) _Py_DECREF_SPECIALIZED(PyStackRef_AsPyObjectBorrow(stackref), dealloc)
 
 #endif // Py_GIL_DISABLED
 

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
@@ -474,8 +474,8 @@ dummy_func(
 
             STAT_INC(BINARY_OP, hit);
             PyObject *res_o = _PyLong_Multiply((PyLongObject *)left_o, (PyLongObject *)right_o);
-            _Py_DECREF_SPECIALIZED(right_o, (destructor)PyObject_Free);
-            _Py_DECREF_SPECIALIZED(left_o, (destructor)PyObject_Free);
+            PyStackRef_CLOSE_SPECIALIZED(right, (destructor)PyObject_Free);
+            PyStackRef_CLOSE_SPECIALIZED(left, (destructor)PyObject_Free);
             INPUTS_DEAD();
             ERROR_IF(res_o == NULL, error);
             res = PyStackRef_FromPyObjectSteal(res_o);
@@ -487,8 +487,8 @@ dummy_func(
 
             STAT_INC(BINARY_OP, hit);
             PyObject *res_o = _PyLong_Add((PyLongObject *)left_o, (PyLongObject *)right_o);
-            _Py_DECREF_SPECIALIZED(right_o, (destructor)PyObject_Free);
-            _Py_DECREF_SPECIALIZED(left_o, (destructor)PyObject_Free);
+            PyStackRef_CLOSE_SPECIALIZED(right, (destructor)PyObject_Free);
+            PyStackRef_CLOSE_SPECIALIZED(left, (destructor)PyObject_Free);
             INPUTS_DEAD();
             ERROR_IF(res_o == NULL, error);
             res = PyStackRef_FromPyObjectSteal(res_o);
@@ -500,8 +500,8 @@ dummy_func(
 
             STAT_INC(BINARY_OP, hit);
             PyObject *res_o = _PyLong_Subtract((PyLongObject *)left_o, (PyLongObject *)right_o);
-            _Py_DECREF_SPECIALIZED(right_o, (destructor)PyObject_Free);
-            _Py_DECREF_SPECIALIZED(left_o, (destructor)PyObject_Free);
+            PyStackRef_CLOSE_SPECIALIZED(right, (destructor)PyObject_Free);
+            PyStackRef_CLOSE_SPECIALIZED(left, (destructor)PyObject_Free);
             INPUTS_DEAD();
             ERROR_IF(res_o == NULL, error);
             res = PyStackRef_FromPyObjectSteal(res_o);
@@ -594,8 +594,8 @@ dummy_func(
 
             STAT_INC(BINARY_OP, hit);
             PyObject *res_o = PyUnicode_Concat(left_o, right_o);
-            _Py_DECREF_SPECIALIZED(left_o, _PyUnicode_ExactDealloc);
-            _Py_DECREF_SPECIALIZED(right_o, _PyUnicode_ExactDealloc);
+            PyStackRef_CLOSE_SPECIALIZED(left, _PyUnicode_ExactDealloc);
+            PyStackRef_CLOSE_SPECIALIZED(right, _PyUnicode_ExactDealloc);
             INPUTS_DEAD();
             ERROR_IF(res_o == NULL, error);
             res = PyStackRef_FromPyObjectSteal(res_o);
@@ -636,12 +636,12 @@ dummy_func(
              * that the string is safe to mutate.
              */
             assert(Py_REFCNT(left_o) >= 2);
-            _Py_DECREF_NO_DEALLOC(left_o);
+            PyStackRef_CLOSE(left);
             DEAD(left);
             PyObject *temp = PyStackRef_AsPyObjectBorrow(*target_local);
             PyUnicode_Append(&temp, right_o);
             *target_local = PyStackRef_FromPyObjectSteal(temp);
-            _Py_DECREF_SPECIALIZED(right_o, _PyUnicode_ExactDealloc);
+            PyStackRef_CLOSE_SPECIALIZED(right, _PyUnicode_ExactDealloc);
             DEAD(right);
             ERROR_IF(PyStackRef_IsNull(*target_local), error);
         #if TIER_ONE
@@ -755,7 +755,7 @@ dummy_func(
             PyObject *res_o = PyList_GET_ITEM(list, index);
             assert(res_o != NULL);
             Py_INCREF(res_o);
-            _Py_DECREF_SPECIALIZED(sub, (destructor)PyObject_Free);
+            PyStackRef_CLOSE_SPECIALIZED(sub_st, (destructor)PyObject_Free);
             DEAD(sub_st);
             PyStackRef_CLOSE(list_st);
             res = PyStackRef_FromPyObjectSteal(res_o);
@@ -775,7 +775,7 @@ dummy_func(
             DEOPT_IF(Py_ARRAY_LENGTH(_Py_SINGLETON(strings).ascii) <= c);
             STAT_INC(BINARY_SUBSCR, hit);
             PyObject *res_o = (PyObject*)&_Py_SINGLETON(strings).ascii[c];
-            _Py_DECREF_SPECIALIZED(sub, (destructor)PyObject_Free);
+            PyStackRef_CLOSE_SPECIALIZED(sub_st, (destructor)PyObject_Free);
             DEAD(sub_st);
             PyStackRef_CLOSE(str_st);
             res = PyStackRef_FromPyObjectSteal(res_o);
@@ -796,7 +796,7 @@ dummy_func(
             PyObject *res_o = PyTuple_GET_ITEM(tuple, index);
             assert(res_o != NULL);
             Py_INCREF(res_o);
-            _Py_DECREF_SPECIALIZED(sub, (destructor)PyObject_Free);
+            PyStackRef_CLOSE_SPECIALIZED(sub_st, (destructor)PyObject_Free);
             DEAD(sub_st);
             PyStackRef_CLOSE(tuple_st);
             res = PyStackRef_FromPyObjectSteal(res_o);
@@ -908,7 +908,7 @@ dummy_func(
             PyList_SET_ITEM(list, index, PyStackRef_AsPyObjectSteal(value));
             assert(old_value != NULL);
             Py_DECREF(old_value);
-            _Py_DECREF_SPECIALIZED(sub, (destructor)PyObject_Free);
+            PyStackRef_CLOSE_SPECIALIZED(sub_st, (destructor)PyObject_Free);
             DEAD(sub_st);
             PyStackRef_CLOSE(list_st);
         }
@@ -2398,9 +2398,9 @@ dummy_func(
             double dright = PyFloat_AS_DOUBLE(right_o);
             // 1 if NaN, 2 if <, 4 if >, 8 if ==; this matches low four bits of the oparg
             int sign_ish = COMPARISON_BIT(dleft, dright);
-            _Py_DECREF_SPECIALIZED(left_o, _PyFloat_ExactDealloc);
+            PyStackRef_CLOSE_SPECIALIZED(left, _PyFloat_ExactDealloc);
             DEAD(left);
-            _Py_DECREF_SPECIALIZED(right_o, _PyFloat_ExactDealloc);
+            PyStackRef_CLOSE_SPECIALIZED(right, _PyFloat_ExactDealloc);
             DEAD(right);
             res = (sign_ish & oparg) ? PyStackRef_True : PyStackRef_False;
             // It's always a bool, so we don't care about oparg & 16.
@@ -2420,9 +2420,9 @@ dummy_func(
             Py_ssize_t iright = _PyLong_CompactValue((PyLongObject *)right_o);
             // 2 if <, 4 if >, 8 if ==; this matches the low 4 bits of the oparg
             int sign_ish = COMPARISON_BIT(ileft, iright);
-            _Py_DECREF_SPECIALIZED(left_o, (destructor)PyObject_Free);
+            PyStackRef_CLOSE_SPECIALIZED(left, (destructor)PyObject_Free);
             DEAD(left);
-            _Py_DECREF_SPECIALIZED(right_o, (destructor)PyObject_Free);
+            PyStackRef_CLOSE_SPECIALIZED(right, (destructor)PyObject_Free);
             DEAD(right);
             res =  (sign_ish & oparg) ? PyStackRef_True : PyStackRef_False;
             // It's always a bool, so we don't care about oparg & 16.
@@ -2436,9 +2436,9 @@ dummy_func(
             STAT_INC(COMPARE_OP, hit);
             int eq = _PyUnicode_Equal(left_o, right_o);
             assert((oparg >> 5) == Py_EQ || (oparg >> 5) == Py_NE);
-            _Py_DECREF_SPECIALIZED(left_o, _PyUnicode_ExactDealloc);
+            PyStackRef_CLOSE_SPECIALIZED(left, _PyUnicode_ExactDealloc);
             DEAD(left);
-            _Py_DECREF_SPECIALIZED(right_o, _PyUnicode_ExactDealloc);
+            PyStackRef_CLOSE_SPECIALIZED(right, _PyUnicode_ExactDealloc);
             DEAD(right);
             assert(eq == 0 || eq == 1);
             assert((oparg & 0xf) == COMPARISON_NOT_EQUALS || (oparg & 0xf) == COMPARISON_EQUALS);

diff --git a/Python/executor_cases.c.h b/Python/executor_cases.c.h