https://github.com/python/cpython/commit/556e8556849cb9df0666629b0f564b5dd203344c
commit: 556e8556849cb9df0666629b0f564b5dd203344c
branch: main
author: Sam Gross <[email protected]>
committer: colesbury <[email protected]>
date: 2024-08-23T15:36:14-04:00
summary:
gh-117376: Make `Py_DECREF` a macro in ceval.c in free-threaded build (#122975)
`Py_DECREF` and `PyStackRef_CLOSE` are now implemented as macros in the
free-threaded build in ceval.c. There are two motivations;
* MSVC has problems inlining functions in ceval.c in the PGO build.
* We will want to mark escaping calls in order to spill the stack
pointer in ceval.c and we will want to do this around `_Py_Dealloc`
(or `_Py_MergeZeroLocalRefcount` or `_Py_DecRefShared`), not around
the entire `Py_DECREF` or `PyStackRef_CLOSE` call.
files:
M Include/internal/pycore_stackref.h
M Python/ceval.c
diff --git a/Include/internal/pycore_stackref.h
b/Include/internal/pycore_stackref.h
index 8c9bb1ae8c4908..7c106577671b5f 100644
--- a/Include/internal/pycore_stackref.h
+++ b/Include/internal/pycore_stackref.h
@@ -190,18 +190,15 @@ PyStackRef_FromPyObjectImmortal(PyObject *obj)
} while (0)
#ifdef Py_GIL_DISABLED
-static inline void
-PyStackRef_CLOSE(_PyStackRef stackref)
-{
- if (PyStackRef_IsDeferred(stackref)) {
- // No assert for being immortal or deferred here.
- // The GC unsets deferred objects right before clearing.
- return;
- }
- Py_DECREF(PyStackRef_AsPyObjectBorrow(stackref));
-}
+# define PyStackRef_CLOSE(REF) \
+ do { \
+ _PyStackRef _close_tmp = (REF); \
+ if (!PyStackRef_IsDeferred(_close_tmp)) { \
+ Py_DECREF(PyStackRef_AsPyObjectBorrow(_close_tmp)); \
+ } \
+ } while (0)
#else
-# define PyStackRef_CLOSE(stackref)
Py_DECREF(PyStackRef_AsPyObjectBorrow(stackref));
+# define PyStackRef_CLOSE(stackref)
Py_DECREF(PyStackRef_AsPyObjectBorrow(stackref))
#endif
#define PyStackRef_XCLOSE(stackref) \
@@ -227,7 +224,7 @@ PyStackRef_DUP(_PyStackRef stackref)
return stackref;
}
#else
-# define PyStackRef_DUP(stackref)
PyStackRef_FromPyObjectSteal(Py_NewRef(PyStackRef_AsPyObjectBorrow(stackref)));
+# define PyStackRef_DUP(stackref)
PyStackRef_FromPyObjectSteal(Py_NewRef(PyStackRef_AsPyObjectBorrow(stackref)))
#endif
static inline void
diff --git a/Python/ceval.c b/Python/ceval.c
index b615deec3c4242..2a5c16aa101985 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -52,13 +52,27 @@
# error "ceval.c must be build with Py_BUILD_CORE define for best performance"
#endif
-#if !defined(Py_DEBUG) && !defined(Py_TRACE_REFS) && !defined(Py_GIL_DISABLED)
+#if !defined(Py_DEBUG) && !defined(Py_TRACE_REFS)
// GH-89279: The MSVC compiler does not inline these static inline functions
// in PGO build in _PyEval_EvalFrameDefault(), because this function is over
// the limit of PGO, and that limit cannot be configured.
// Define them as macros to make sure that they are always inlined by the
// preprocessor.
-// TODO: implement Py_DECREF macro for Py_GIL_DISABLED
+
+#undef Py_IS_TYPE
+#define Py_IS_TYPE(ob, type) \
+ (_PyObject_CAST(ob)->ob_type == (type))
+
+#undef Py_XDECREF
+#define Py_XDECREF(arg) \
+ do { \
+ PyObject *xop = _PyObject_CAST(arg); \
+ if (xop != NULL) { \
+ Py_DECREF(xop); \
+ } \
+ } while (0)
+
+#ifndef Py_GIL_DISABLED
#undef Py_DECREF
#define Py_DECREF(arg) \
@@ -74,19 +88,6 @@
} \
} while (0)
-#undef Py_XDECREF
-#define Py_XDECREF(arg) \
- do { \
- PyObject *xop = _PyObject_CAST(arg); \
- if (xop != NULL) { \
- Py_DECREF(xop); \
- } \
- } while (0)
-
-#undef Py_IS_TYPE
-#define Py_IS_TYPE(ob, type) \
- (_PyObject_CAST(ob)->ob_type == (type))
-
#undef _Py_DECREF_SPECIALIZED
#define _Py_DECREF_SPECIALIZED(arg, dealloc) \
do { \
@@ -100,6 +101,34 @@
d(op); \
} \
} while (0)
+
+#else // Py_GIL_DISABLED
+
+#undef Py_DECREF
+#define Py_DECREF(arg) \
+ do { \
+ PyObject *op = _PyObject_CAST(arg); \
+ uint32_t local = _Py_atomic_load_uint32_relaxed(&op->ob_ref_local); \
+ if (local == _Py_IMMORTAL_REFCNT_LOCAL) { \
+ break; \
+ } \
+ _Py_DECREF_STAT_INC(); \
+ if (_Py_IsOwnedByCurrentThread(op)) { \
+ local--; \
+ _Py_atomic_store_uint32_relaxed(&op->ob_ref_local, local); \
+ if (local == 0) { \
+ _Py_MergeZeroLocalRefcount(op); \
+ } \
+ } \
+ else { \
+ _Py_DecRefShared(op); \
+ } \
+ } while (0)
+
+#undef _Py_DECREF_SPECIALIZED
+#define _Py_DECREF_SPECIALIZED(arg, dealloc) Py_DECREF(arg)
+
+#endif
#endif
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