blob: 97391e2c124b759f23eaadcb14fc4913ee6bcfa7 [file] [log] [blame]
Andrew Geisslerc5535c92023-01-27 16:10:19 -06001From f9ac08a0fea543d68b2dba540093bd079e50be47 Mon Sep 17 00:00:00 2001
2From: Khem Raj <raj.khem@gmail.com>
3Date: Sun, 15 Jan 2023 15:49:09 -0800
4Subject: [PATCH] Define _ALIGN using _Alignof when using C11 or newer
5
6WG14 N2350 made very clear that it is an UB having type definitions
7within "offsetof" [1]. This patch enhances the implementation of macro
8_ALIGN to use builtin "_Alignof" to avoid undefined behavior on
9when using std=c11 or newer
10
11clang 16+ has started to flag this [2]
12
13Fixes build when using -std >= gnu11 and using clang16+
14
15Older compilers gcc < 4.9 or clang < 8 has buggy _Alignof even though it
16may support C11, exclude those compilers too
17
18[1] https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm
19[2] https://reviews.llvm.org/D133574
20
21Upstream-Status: Submitted [https://github.com/numpy/numpy/pull/23016]
22Signed-off-by: Khem Raj <raj.khem@gmail.com>
23---
24 numpy/core/src/multiarray/arraytypes.c.src | 13 +++++++++++--
25 numpy/core/src/multiarray/common.h | 12 +++++++++++-
26 2 files changed, 22 insertions(+), 3 deletions(-)
27
28diff --git a/numpy/core/src/multiarray/arraytypes.c.src b/numpy/core/src/multiarray/arraytypes.c.src
29index c03d09784..683917220 100644
30--- a/numpy/core/src/multiarray/arraytypes.c.src
31+++ b/numpy/core/src/multiarray/arraytypes.c.src
32@@ -224,8 +224,17 @@ MyPyLong_AsUnsigned@Type@(PyObject *obj)
33 ** GETITEM AND SETITEM **
34 *****************************************************************************
35 */
36-
37-#define _ALIGN(type) offsetof(struct {char c; type v;}, v)
38+/* GCC releases before GCC 4.9 had a bug in _Alignof. See GCC bug 52023
39+ <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52023>.
40+ clang versions < 8.0.0 have the same bug. */
41+#if (!defined __STDC_VERSION__ || __STDC_VERSION__ < 201112 \
42+ || (defined __GNUC__ && __GNUC__ < 4 + (__GNUC_MINOR__ < 9) \
43+ && !defined __clang__) \
44+ || (defined __clang__ && __clang_major__ < 8))
45+# define _ALIGN(type) offsetof(struct {char c; type v;}, v)
46+#else
47+# define _ALIGN(type) _Alignof(type)
48+#endif
49 /*
50 * Disable harmless compiler warning "4116: unnamed type definition in
51 * parentheses" which is caused by the _ALIGN macro.
52diff --git a/numpy/core/src/multiarray/common.h b/numpy/core/src/multiarray/common.h
53index 3de8c842d..d01074c45 100644
54--- a/numpy/core/src/multiarray/common.h
55+++ b/numpy/core/src/multiarray/common.h
56@@ -178,7 +178,17 @@ check_and_adjust_axis(int *axis, int ndim)
57 }
58
59 /* used for some alignment checks */
60-#define _ALIGN(type) offsetof(struct {char c; type v;}, v)
61+/* GCC releases before GCC 4.9 had a bug in _Alignof. See GCC bug 52023
62+ <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52023>.
63+ clang versions < 8.0.0 have the same bug. */
64+#if (!defined __STDC_VERSION__ || __STDC_VERSION__ < 201112 \
65+ || (defined __GNUC__ && __GNUC__ < 4 + (__GNUC_MINOR__ < 9) \
66+ && !defined __clang__) \
67+ || (defined __clang__ && __clang_major__ < 8))
68+# define _ALIGN(type) offsetof(struct {char c; type v;}, v)
69+#else
70+# define _ALIGN(type) _Alignof(type)
71+#endif
72 #define _UINT_ALIGN(type) npy_uint_alignment(sizeof(type))
73 /*
74 * Disable harmless compiler warning "4116: unnamed type definition in
75--
762.39.0
77