| From d55b6b1fa87700f3eae3a29522972d2e7be7d53e Mon Sep 17 00:00:00 2001 |
| From: Khem Raj <raj.khem@gmail.com> |
| Date: Sat, 14 Jan 2023 10:11:35 -0800 |
| Subject: [PATCH] use _Alignof to avoid UB in ALIGNOF |
| |
| WG14 N2350 clearly says that it is an UB having type definitions |
| within "offsetof" [1]. Clang 16+ has started diagnosing it [2]. |
| This patch changes the implementation of macro |
| "ALIGNOF" to builtin "_Alignof" to avoid undefined behavior. |
| |
| _Alignof() return the ABI required minimum alignment. |
| |
| [1] https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm |
| [2] https://reviews.llvm.org/D133574 |
| |
| Upstream-Status: Submitted [https://gitlab.freedesktop.org/xorg/lib/libxcb/-/merge_requests/42] |
| Signed-off-by: Khem Raj <raj.khem@gmail.com> |
| --- |
| src/c_client.py | 3 +-- |
| 1 file changed, 1 insertion(+), 2 deletions(-) |
| |
| diff --git a/src/c_client.py b/src/c_client.py |
| index fd256f0..4e48f13 100644 |
| --- a/src/c_client.py |
| +++ b/src/c_client.py |
| @@ -288,7 +288,6 @@ def c_open(self): |
| _c('#include "%s.h"', _ns.header) |
| |
| _c('') |
| - _c('#define ALIGNOF(type) offsetof(struct { char dummy; type member; }, member)') |
| |
| if _ns.is_ext: |
| for (n, h) in self.direct_imports: |
| @@ -1266,7 +1265,7 @@ def _c_serialize_helper_fields(context, self, |
| count += 1 |
| |
| code_lines.append( |
| - '%s xcb_align_to = ALIGNOF(%s);' |
| + '%s xcb_align_to = _Alignof(%s);' |
| % (space, |
| 'char' |
| if field.c_field_type == 'void' or field.type.is_switch |
| -- |
| 2.39.0 |
| |