python2/00293-fix-gc-alignment.patch
2018-01-31 13:40:48 +01:00

40 lines
1.2 KiB
Diff

Fix for over-aligned GC info
Patch by Florian Weimer
See: https://bugzilla.redhat.com/show_bug.cgi?id=1540316
Upstream discussion: https://mail.python.org/pipermail/python-dev/2018-January/152000.html
diff --git a/Include/objimpl.h b/Include/objimpl.h
index 55e83eced6..aa906144dc 100644
--- a/Include/objimpl.h
+++ b/Include/objimpl.h
@@ -248,6 +248,18 @@ PyAPI_FUNC(PyVarObject *) _PyObject_GC_Resize(PyVarObject *, Py_ssize_t);
/* for source compatibility with 2.2 */
#define _PyObject_GC_Del PyObject_GC_Del
+/* Former over-aligned definition of PyGC_Head, used to compute the
+ size of the padding for the new version below. */
+union _gc_head;
+union _gc_head_old {
+ struct {
+ union _gc_head *gc_next;
+ union _gc_head *gc_prev;
+ Py_ssize_t gc_refs;
+ } gc;
+ long double dummy;
+};
+
/* GC information is stored BEFORE the object structure. */
typedef union _gc_head {
struct {
@@ -255,7 +267,8 @@ typedef union _gc_head {
union _gc_head *gc_prev;
Py_ssize_t gc_refs;
} gc;
- long double dummy; /* force worst-case alignment */
+ double dummy; /* force worst-case alignment */
+ char dummy_padding[sizeof(union _gc_head_old)];
} PyGC_Head;
extern PyGC_Head *_PyGC_generation0;