GH-137759:Limit _PyObject_HashFast to dicts keys, rename it, and mark it as Py_ALWAYS_INLINE

Author: JasonMendoza2008

Include/internal/pycore_object.h

@@ -858,9 +858,11 @@ _PyObject_IS_GC(PyObject *obj)
             && (type->tp_is_gc == NULL || type->tp_is_gc(obj)));
 }
 
-// Fast inlined version of PyObject_Hash()
-static inline Py_hash_t
-_PyObject_HashFast(PyObject *op)
+// Fast inlined version of PyObject_Hash(). Dictionaries are very
+// likely to include string keys (class and instance attributes,
+// json, ...) so we include a fast path for strings.
+static inline Py_ALWAYS_INLINE Py_hash_t
+_PyObject_HashDictKey(PyObject *op)
 {
     if (PyUnicode_CheckExact(op)) {
         Py_hash_t hash = FT_ATOMIC_LOAD_SSIZE_RELAXED(

Modules/_collectionsmodule.c

@@ -2565,7 +2565,7 @@ _collections__count_elements_impl(PyObject *module, PyObject *mapping,
             if (key == NULL)
                 break;
 
-            hash = _PyObject_HashFast(key);
+            hash = _PyObject_HashDictKey(key);
             if (hash == -1) {
                 goto done;
             }

Objects/dictobject.c

@@ -2281,7 +2281,7 @@ dict_getitem(PyObject *op, PyObject *key, const char *warnmsg)
     }
     PyDictObject *mp = (PyDictObject *)op;
 
-    Py_hash_t hash = _PyObject_HashFast(key);
+    Py_hash_t hash = _PyObject_HashDictKey(key);
     if (hash == -1) {
         PyErr_FormatUnraisable(warnmsg);
         return NULL;
@@ -2349,7 +2349,7 @@ _PyDict_LookupIndex(PyDictObject *mp, PyObject *key)
     assert(PyDict_CheckExact((PyObject*)mp));
     assert(PyUnicode_CheckExact(key));
 
-    Py_hash_t hash = _PyObject_HashFast(key);
+    Py_hash_t hash = _PyObject_HashDictKey(key);
     if (hash == -1) {
         dict_unhashable_type(key);
         return -1;
@@ -2446,7 +2446,7 @@ PyDict_GetItemRef(PyObject *op, PyObject *key, PyObject **result)
         return -1;
     }
 
-    Py_hash_t hash = _PyObject_HashFast(key);
+    Py_hash_t hash = _PyObject_HashDictKey(key);
     if (hash == -1) {
         dict_unhashable_type(key);
         *result = NULL;
@@ -2462,7 +2462,7 @@ _PyDict_GetItemRef_Unicode_LockHeld(PyDictObject *op, PyObject *key, PyObject **
     ASSERT_DICT_LOCKED(op);
     assert(PyUnicode_CheckExact(key));
 
-    Py_hash_t hash = _PyObject_HashFast(key);
+    Py_hash_t hash = _PyObject_HashDictKey(key);
     if (hash == -1) {
         dict_unhashable_type(key);
         *result = NULL;
@@ -2500,7 +2500,7 @@ PyDict_GetItemWithError(PyObject *op, PyObject *key)
         PyErr_BadInternalCall();
         return NULL;
     }
-    hash = _PyObject_HashFast(key);
+    hash = _PyObject_HashDictKey(key);
     if (hash == -1) {
         dict_unhashable_type(key);
         return NULL;
@@ -2571,7 +2571,7 @@ _PyDict_LoadGlobal(PyDictObject *globals, PyDictObject *builtins, PyObject *key)
     Py_hash_t hash;
     PyObject *value;
 
-    hash = _PyObject_HashFast(key);
+    hash = _PyObject_HashDictKey(key);
     if (hash == -1) {
         return NULL;
     }
@@ -2595,7 +2595,7 @@ _PyDict_LoadGlobalStackRef(PyDictObject *globals, PyDictObject *builtins, PyObje
     Py_ssize_t ix;
     Py_hash_t hash;
 
-    hash = _PyObject_HashFast(key);
+    hash = _PyObject_HashDictKey(key);
     if (hash == -1) {
         *res = PyStackRef_NULL;
         return;
@@ -2658,7 +2658,7 @@ setitem_take2_lock_held(PyDictObject *mp, PyObject *key, PyObject *value)
     assert(key);
     assert(value);
     assert(PyDict_Check(mp));
-    Py_hash_t hash = _PyObject_HashFast(key);
+    Py_hash_t hash = _PyObject_HashDictKey(key);
     if (hash == -1) {
         dict_unhashable_type(key);
         Py_DECREF(key);
@@ -2810,7 +2810,7 @@ int
 PyDict_DelItem(PyObject *op, PyObject *key)
 {
     assert(key);
-    Py_hash_t hash = _PyObject_HashFast(key);
+    Py_hash_t hash = _PyObject_HashDictKey(key);
     if (hash == -1) {
         dict_unhashable_type(key);
         return -1;
@@ -3138,7 +3138,7 @@ pop_lock_held(PyObject *op, PyObject *key, PyObject **result)
         return 0;
     }
 
-    Py_hash_t hash = _PyObject_HashFast(key);
+    Py_hash_t hash = _PyObject_HashDictKey(key);
     if (hash == -1) {
         dict_unhashable_type(key);
         if (result) {
@@ -3472,7 +3472,7 @@ dict_subscript(PyObject *self, PyObject *key)
     Py_hash_t hash;
     PyObject *value;
 
-    hash = _PyObject_HashFast(key);
+    hash = _PyObject_HashDictKey(key);
     if (hash == -1) {
         dict_unhashable_type(key);
         return NULL;
@@ -4353,7 +4353,7 @@ dict_get_impl(PyDictObject *self, PyObject *key, PyObject *default_value)
     Py_hash_t hash;
     Py_ssize_t ix;
 
-    hash = _PyObject_HashFast(key);
+    hash = _PyObject_HashDictKey(key);
     if (hash == -1) {
         dict_unhashable_type(key);
         return NULL;
@@ -4386,7 +4386,7 @@ dict_setdefault_ref_lock_held(PyObject *d, PyObject *key, PyObject *default_valu
         return -1;
     }
 
-    hash = _PyObject_HashFast(key);
+    hash = _PyObject_HashDictKey(key);
     if (hash == -1) {
         dict_unhashable_type(key);
         if (result) {
@@ -4816,7 +4816,7 @@ static PyMethodDef mapp_methods[] = {
 int
 PyDict_Contains(PyObject *op, PyObject *key)
 {
-    Py_hash_t hash = _PyObject_HashFast(key);
+    Py_hash_t hash = _PyObject_HashDictKey(key);
     if (hash == -1) {
         dict_unhashable_type(key);
         return -1;
@@ -6903,7 +6903,7 @@ int
 _PyDict_SetItem_LockHeld(PyDictObject *dict, PyObject *name, PyObject *value)
 {
     if (value == NULL) {
-        Py_hash_t hash = _PyObject_HashFast(name);
+        Py_hash_t hash = _PyObject_HashDictKey(name);
         if (hash == -1) {
             dict_unhashable_type(name);
             return -1;

Objects/setobject.c

@@ -231,7 +231,7 @@ set_unhashable_type(PyObject *key)
 int
 _PySet_AddTakeRef(PySetObject *so, PyObject *key)
 {
-    Py_hash_t hash = _PyObject_HashFast(key);
+    Py_hash_t hash = PyObject_Hash(key);
     if (hash == -1) {
         set_unhashable_type(key);
         Py_DECREF(key);
@@ -400,7 +400,7 @@ set_discard_entry(PySetObject *so, PyObject *key, Py_hash_t hash)
 static int
 set_add_key(PySetObject *so, PyObject *key)
 {
-    Py_hash_t hash = _PyObject_HashFast(key);
+    Py_hash_t hash = PyObject_Hash(key);
     if (hash == -1) {
         set_unhashable_type(key);
         return -1;
@@ -411,7 +411,7 @@ set_add_key(PySetObject *so, PyObject *key)
 static int
 set_contains_key(PySetObject *so, PyObject *key)
 {
-    Py_hash_t hash = _PyObject_HashFast(key);
+    Py_hash_t hash = PyObject_Hash(key);
     if (hash == -1) {
         set_unhashable_type(key);
         return -1;
@@ -422,7 +422,7 @@ set_contains_key(PySetObject *so, PyObject *key)
 static int
 set_discard_key(PySetObject *so, PyObject *key)
 {
-    Py_hash_t hash = _PyObject_HashFast(key);
+    Py_hash_t hash = PyObject_Hash(key);
     if (hash == -1) {
         set_unhashable_type(key);
         return -1;

Objects/typeobject.c

@@ -3749,7 +3749,7 @@ solid_base(PyTypeObject *type)
 // or when __bases__ is re-assigned.  Since the slots are read without atomic
 // operations and without locking, we can only safely update them while the
 // world is stopped.  However, with the world stopped, we are very limited on
-// which APIs can be safely used.  For example, calling _PyObject_HashFast()
+// which APIs can be safely used.  For example, calling _PyObject_HashDictKey()
 // or _PyDict_GetItemRef_KnownHash() are not safe and can potentially cause
 // deadlocks.  Hashing can be re-entrant and _PyDict_GetItemRef_KnownHash can
 // acquire a lock if the dictionary is not owned by the current thread, to
@@ -5898,7 +5898,7 @@ PyObject_GetItemData(PyObject *obj)
 static PyObject *
 find_name_in_mro(PyTypeObject *type, PyObject *name, int *error)
 {
-    Py_hash_t hash = _PyObject_HashFast(name);
+    Py_hash_t hash = _PyObject_HashDictKey(name);
     if (hash == -1) {
         *error = -1;
         return NULL;