bpo-27987: align PyGC_Head to alignof(long double) (GH-13335) · python/cpython@ea2b76b (original) (raw)

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2 files changed

lines changed

Misc/NEWS.d/next/Core and Builtins

2 files changed

lines changed

Original file line number	Diff line number	Diff line change
@@ -255,7 +255,11 @@ typedef union _gc_head {
255	255	union _gc_head *gc_prev;
256	256	Py_ssize_t gc_refs;
257	257	} gc;
258		-double dummy; /* force worst-case alignment */
	258	+long double dummy; /* force worst-case alignment */
	259	+// malloc returns memory block aligned for any built-in types and
	260	+// long double is the largest standard C type.
	261	+// On amd64 linux, long double requires 16 byte alignment.
	262	+// See bpo-27987 for more discussion.
259	263	} PyGC_Head;
260	264
261	265	extern PyGC_Head *_PyGC_generation0;

Original file line number	Diff line number	Diff line change
@@ -0,0 +1,2 @@
	1	+``PyGC_Head`` structure is aligned to ``long double``. This is needed to
	2	+GC-ed objects are aligned properly. Patch by Inada Naoki.