python2: Fix build with gcc8

(From OE-Core rev: 910f68c9c8dc26e12d28ef29e956af63d100f121)

(From OE-Core rev: 04c2d53ef48a09747d0577d9ec1ffa548d247615)

(From OE-Core rev: 9a3772e9411864301ca2799b4d5827476a6b7fcf)

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Martin Hundebøll <martin@geanix.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Armin Kuster <akuster808@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 43 insertions, 0 deletions

diff --git a/meta/recipes-devtools/python/python/fix-gc-alignment.patch b/meta/recipes-devtools/python/python/fix-gc-alignment.patch
new file mode 100644
index 0000000000..b63cd08747
--- /dev/null
+++ b/meta/recipes-devtools/python/python/fix-gc-alignment.patch
@@ -0,0 +1,43 @@
+Upstream-Status: Submitted
+Signed-off-by: Ross Burton <ross.burton@intel.com>
+
+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;
+ 
\ No newline at end of file