Add Lazy Imports to 3.14t

Summary:
Add Lazy Imports to the free-threaded build of Meta Python 3.14. Lazy Imports was added to the gil build of Meta Python 3.14 in D83595369.

This Diff is the result of squashing this stack: D85054995. The stack must be landed in one commit to avoid introducing any dangerous behavior in 3.14t.

Reviewed By: DinoV

Differential Revision: D85977460

fbshipit-source-id: f11501c8996c55cb83952016916f88b5f9d05636

Author: Subbarao Garlapati

Include/cpython/pyatomic.h

@@ -544,6 +544,12 @@ _Py_atomic_load_uint32_acquire(const uint32_t *obj);
 static inline Py_ssize_t
 _Py_atomic_load_ssize_acquire(const Py_ssize_t *obj);
 
+static inline void
+_Py_atomic_store_uchar_release(unsigned char *obj, unsigned char value);
+
+static inline unsigned char
+_Py_atomic_load_uchar_acquire(const unsigned char *obj);
+
 
 
 

Include/cpython/pyatomic_gcc.h

@@ -600,6 +600,14 @@ static inline Py_ssize_t
 _Py_atomic_load_ssize_acquire(const Py_ssize_t *obj)
 { return __atomic_load_n(obj, __ATOMIC_ACQUIRE); }
 
+static inline unsigned char
+_Py_atomic_load_uchar_acquire(const unsigned char *obj)
+{ return __atomic_load_n(obj, __ATOMIC_ACQUIRE); }
+
+static inline void
+_Py_atomic_store_uchar_release(unsigned char *obj, unsigned char value)
+{ __atomic_store_n(obj, value, __ATOMIC_RELEASE); }
+
 // --- _Py_atomic_fence ------------------------------------------------------
 
 static inline void

Include/cpython/pyatomic_std.h

@@ -1087,6 +1087,22 @@ _Py_atomic_load_ssize_acquire(const Py_ssize_t *obj)
                                 memory_order_acquire);
 }
 
+static inline void
+_Py_atomic_store_uchar_release(unsigned char *obj, unsigned char value)
+{
+    _Py_USING_STD;
+    atomic_store_explicit((_Atomic(unsigned char)*)obj, value,
+                           memory_order_release);
+}
+
+static inline unsigned char
+_Py_atomic_load_uchar_acquire(const unsigned char *obj)
+{
+    _Py_USING_STD;
+    return atomic_load_explicit((const _Atomic(unsigned char)*)obj,
+                                memory_order_acquire);
+}
+
 
 // --- _Py_atomic_fence ------------------------------------------------------
 

Include/internal/pycore_dict.h

@@ -174,9 +174,24 @@ PyAPI_FUNC(void) _PyDict_EnsureSharedOnRead(PyDictObject *mp);
 typedef enum {
     DICT_KEYS_GENERAL = 0,
     DICT_KEYS_UNICODE = 1,
-    DICT_KEYS_SPLIT = 2
+    DICT_KEYS_SPLIT = 2,
+    DICT_KEYS_LAZY_IMPORTS = 0x80,
 } DictKeysKind;
 
+#define DICT_KEYS_KIND_MASK 0x03
+#define DICT_KEYS_LAZY_IMPORTS_MASK 0x80
+
+#ifdef ENABLE_LAZY_IMPORTS
+#define LOAD_SHARED_UCHAR(obj) _Py_atomic_load_uchar_acquire(&obj)
+#define STORE_SHARED_UCHAR(obj, value) _Py_atomic_store_uchar_release(&obj, value)
+#define DK_KIND(dk) (LOAD_SHARED_UCHAR(dk->dk_kind) & DICT_KEYS_KIND_MASK)
+#define DK_LAZY_IMPORTS(dk) (LOAD_SHARED_UCHAR(dk->dk_kind) & DICT_KEYS_LAZY_IMPORTS)
+#else
+#define LOAD_SHARED_UCHAR(obj) obj
+#define STORE_SHARED_UCHAR(obj, value) obj = value
+#define DK_KIND(dk) (dk->dk_kind)
+#endif
+
 /* See dictobject.c for actual layout of DictKeysObject */
 struct _dictkeysobject {
     Py_ssize_t dk_refcnt;
@@ -187,15 +202,8 @@ struct _dictkeysobject {
     /* Size of the hash table (dk_indices) by bytes. */
     uint8_t dk_log2_index_bytes;
 
-    /* Kind of keys */
-#ifdef ENABLE_LAZY_IMPORTS
-    uint8_t dk_kind: 7;
-
-    /* Contains lazy imports. Assume there are lazy import objects unless otherwise specified. */
-    uint8_t dk_lazy_imports : 1;
-#else
+    /* Kind of keys (use `DICT_KEYS_KIND_MASK` to get kind, `DICT_KEYS_LAZY_IMPORTS` flag for lazy imports) */
     uint8_t dk_kind;
-#endif
 
 #ifdef Py_GIL_DISABLED
     /* Lock used to protect shared keys */
@@ -263,15 +271,15 @@ static inline void* _DK_ENTRIES(PyDictKeysObject *dk) {
 }
 
 static inline PyDictKeyEntry* DK_ENTRIES(PyDictKeysObject *dk) {
-    assert(dk->dk_kind == DICT_KEYS_GENERAL);
+    assert(DK_KIND(dk) == DICT_KEYS_GENERAL);
     return (PyDictKeyEntry*)_DK_ENTRIES(dk);
 }
 static inline PyDictUnicodeEntry* DK_UNICODE_ENTRIES(PyDictKeysObject *dk) {
-    assert(dk->dk_kind != DICT_KEYS_GENERAL);
+    assert(DK_KIND(dk) != DICT_KEYS_GENERAL);
     return (PyDictUnicodeEntry*)_DK_ENTRIES(dk);
 }
 
-#define DK_IS_UNICODE(dk) ((dk)->dk_kind != DICT_KEYS_GENERAL)
+#define DK_IS_UNICODE(dk) (DK_KIND(dk) != DICT_KEYS_GENERAL)
 
 #define DICT_VERSION_INCREMENT (1 << (DICT_MAX_WATCHERS + DICT_WATCHED_MUTATION_BITS))
 #define DICT_WATCHER_MASK ((1 << DICT_MAX_WATCHERS) - 1)

Include/internal/pycore_interp_structs.h

@@ -980,6 +980,7 @@ struct _is {
     PyObject *excluding_modules;
     PyObject *eager_imports;
     PyObject *lazy_modules;
+    PyMutex lazy_imports_mutex;
 #endif
 };
 

Lib/test/test_lazy_imports.py

@@ -10,9 +10,6 @@
 
 class LazyImportsTest(unittest.TestCase):
     def test_lazy_imports(self):
-        # TODO-META: Remove when Lazy Imports is added to 3.14t
-        if not sys._is_gil_enabled():
-            return
         original_lazy_modules = sys.lazy_modules.copy()
         original_modules = sys.modules.copy()
         try: