Repaired the debug Windows deaths in test_descr, by allocating enough
pad memory to properly align the __dict__ pointer in all cases.
gcmodule.c/objimpl.h, _PyObject_GC_Malloc:
+ Added a "padding" argument so that this flavor of malloc can allocate
enough bytes for alignment padding (it can't know this is needed, but
its callers do).
typeobject.c, PyType_GenericAlloc:
+ Allocated enough bytes to align the __dict__ pointer.
+ Sped and simplified the round-up-to-PTRSIZE logic.
+ Added blank lines so I could parse the if/else blocks <0.7 wink>.
diff --git a/Include/objimpl.h b/Include/objimpl.h
index 0fd6652..e24d42e 100644
--- a/Include/objimpl.h
+++ b/Include/objimpl.h
@@ -230,7 +230,8 @@
#define PyObject_IS_GC(o) (PyType_IS_GC((o)->ob_type) && \
((o)->ob_type->tp_is_gc == NULL || (o)->ob_type->tp_is_gc(o)))
-extern DL_IMPORT(PyObject *) _PyObject_GC_Malloc(PyTypeObject *, int);
+extern DL_IMPORT(PyObject *) _PyObject_GC_Malloc(PyTypeObject *,
+ int nitems, size_t padding);
extern DL_IMPORT(PyVarObject *) _PyObject_GC_Resize(PyVarObject *, int);
#define PyObject_GC_Resize(type, op, n) \
diff --git a/Modules/gcmodule.c b/Modules/gcmodule.c
index 43a7bf1..349ba6a 100644
--- a/Modules/gcmodule.c
+++ b/Modules/gcmodule.c
@@ -798,13 +798,14 @@
}
PyObject *
-_PyObject_GC_Malloc(PyTypeObject *tp, int size)
+_PyObject_GC_Malloc(PyTypeObject *tp, int nitems, size_t padding)
{
PyObject *op;
#ifdef WITH_CYCLE_GC
- const size_t nbytes = sizeof(PyGC_Head) +
- (size_t)_PyObject_VAR_SIZE(tp, size);
- PyGC_Head *g = PyObject_MALLOC(nbytes);
+ const size_t basic = (size_t)_PyObject_VAR_SIZE(tp, nitems);
+ const size_t nbytes = sizeof(PyGC_Head) + basic + padding;
+
+ PyGC_Head *g = PyObject_MALLOC(nbytes);
if (g == NULL)
return (PyObject *)PyErr_NoMemory();
g->gc_next = NULL;
@@ -820,7 +821,7 @@
}
op = FROM_GC(g);
#else
- op = PyObject_MALLOC(_PyObject_VAR_SIZE(tp, size));
+ op = PyObject_MALLOC(_PyObject_VAR_SIZE(tp, nitems) + padding);
if (op == NULL)
return (PyObject *)PyErr_NoMemory();
@@ -831,14 +832,14 @@
PyObject *
_PyObject_GC_New(PyTypeObject *tp)
{
- PyObject *op = _PyObject_GC_Malloc(tp, 0);
+ PyObject *op = _PyObject_GC_Malloc(tp, 0, 0);
return PyObject_INIT(op, tp);
}
PyVarObject *
_PyObject_GC_NewVar(PyTypeObject *tp, int size)
{
- PyVarObject *op = (PyVarObject *) _PyObject_GC_Malloc(tp, size);
+ PyVarObject *op = (PyVarObject *) _PyObject_GC_Malloc(tp, size, 0);
return PyObject_INIT_VAR(op, tp, size);
}
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index fed6c43..59ec588 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -192,32 +192,42 @@
{
#define PTRSIZE (sizeof(PyObject *))
- int size;
+ size_t size = (size_t)_PyObject_VAR_SIZE(type, nitems);
+ size_t padding = 0;
PyObject *obj;
- /* Inline PyObject_New() so we can zero the memory */
- size = _PyObject_VAR_SIZE(type, nitems);
- /* Round up size, if necessary, so we fully zero out __dict__ */
- if (type->tp_itemsize % PTRSIZE != 0) {
- size += PTRSIZE - 1;
- size /= PTRSIZE;
- size *= PTRSIZE;
+ /* Round up size, if necessary, so that the __dict__ pointer
+ following the variable part is properly aligned for the platform.
+ This is needed only for types with a vrbl number of items
+ before the __dict__ pointer == types that record the dict offset
+ as a negative offset from the end of the object. If tp_dictoffset
+ is 0, there is no __dict__; if positive, tp_dict was declared in a C
+ struct so the compiler already took care of aligning it. */
+ if (type->tp_dictoffset < 0) {
+ padding = PTRSIZE - size % PTRSIZE;
+ if (padding == PTRSIZE)
+ padding = 0;
+ size += padding;
}
- if (PyType_IS_GC(type)) {
- obj = _PyObject_GC_Malloc(type, nitems);
- }
- else {
+
+ if (PyType_IS_GC(type))
+ obj = _PyObject_GC_Malloc(type, nitems, padding);
+ else
obj = PyObject_MALLOC(size);
- }
+
if (obj == NULL)
return PyErr_NoMemory();
+
memset(obj, '\0', size);
+
if (type->tp_flags & Py_TPFLAGS_HEAPTYPE)
Py_INCREF(type);
+
if (type->tp_itemsize == 0)
PyObject_INIT(obj, type);
else
(void) PyObject_INIT_VAR((PyVarObject *)obj, type, nitems);
+
if (PyType_IS_GC(type))
_PyObject_GC_TRACK(obj);
return obj;