diff options
Diffstat (limited to 'Include/object.h')
| -rw-r--r-- | Include/object.h | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/Include/object.h b/Include/object.h index 42aed614d4a..c75e9db0cbd 100644 --- a/Include/object.h +++ b/Include/object.h @@ -101,6 +101,12 @@ whose size is determined when the object is allocated. #define PyObject_VAR_HEAD PyVarObject ob_base; #define Py_INVALID_SIZE (Py_ssize_t)-1 +/* PyObjects are given a minimum alignment so that the least significant bits + * of an object pointer become available for other purposes. + * This must be an integer literal with the value (1 << _PyGC_PREV_SHIFT), number of bytes. + */ +#define _PyObject_MIN_ALIGNMENT 4 + /* Nothing is actually declared to be a PyObject, but every pointer to * a Python object can be cast to a PyObject*. This is inheritance built * by hand. Similarly every pointer to a variable-size Python object can, @@ -136,6 +142,7 @@ struct _object { #else Py_ssize_t ob_refcnt; #endif + _Py_ALIGNED_DEF(_PyObject_MIN_ALIGNMENT, char) _aligner; }; #ifdef _MSC_VER __pragma(warning(pop)) @@ -153,7 +160,7 @@ struct _object { // ob_tid stores the thread id (or zero). It is also used by the GC and the // trashcan mechanism as a linked list pointer and by the GC to store the // computed "gc_refs" refcount. - uintptr_t ob_tid; + _Py_ALIGNED_DEF(_PyObject_MIN_ALIGNMENT, uintptr_t) ob_tid; uint16_t ob_flags; PyMutex ob_mutex; // per-object lock uint8_t ob_gc_bits; // gc-related state |