From 4089affd371e6d62dd8c1e57b344f8cc329005ea Mon Sep 17 00:00:00 2001 From: Khem Raj Date: Sat, 14 Jan 2023 23:11:08 -0800 Subject: [PATCH] Define alignof using _Alignof when using C11 or newer WG14 N2350 made very clear that it is an UB having type definitions within "offsetof" [1]. This patch enhances the implementation of macro alignof_slot to use builtin "_Alignof" to avoid undefined behavior on when using std=c11 or newer clang 16+ has started to flag this [2] Fixes build when using -std >= gnu11 and using clang16+ Older compilers gcc < 4.9 or clang < 8 has buggy _Alignof even though it may support C11, exclude those compilers too [1] https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm [2] https://reviews.llvm.org/D133574 Upstream-Status: Submitted [https://groups.google.com/g/opkg-devel/c/gjcQPZgT_jI] Signed-off-by: Khem Raj --- libopkg/md5.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/libopkg/md5.c b/libopkg/md5.c index 981b9b8..ccb645e 100644 --- a/libopkg/md5.c +++ b/libopkg/md5.c @@ -237,7 +237,17 @@ void md5_process_bytes(const void *buffer, size_t len, struct md5_ctx *ctx) /* Process available complete blocks. */ if (len >= 64) { #if !_STRING_ARCH_unaligned +/* GCC releases before GCC 4.9 had a bug in _Alignof. See GCC bug 52023 + . + clang versions < 8.0.0 have the same bug. */ +#if (!defined __STDC_VERSION__ || __STDC_VERSION__ < 201112 \ + || (defined __GNUC__ && __GNUC__ < 4 + (__GNUC_MINOR__ < 9) \ + && !defined __clang__) \ + || (defined __clang__ && __clang_major__ < 8)) #define alignof(type) offsetof (struct { char c; type x; }, x) +#else +#define alignof(type) _Alignof(type) +#endif #define UNALIGNED_P(p) (((size_t) p) % alignof (uint32_t) != 0) if (UNALIGNED_P(buffer)) while (len > 64) { -- 2.39.0