From d479020609329cdc7fa3675bc3daf072401fefae Mon Sep 17 00:00:00 2001 From: Khem Raj Date: Sun, 15 Jan 2023 00:16:25 -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 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: Pending Signed-off-by: Khem Raj --- libiberty/sha1.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/libiberty/sha1.c b/libiberty/sha1.c index 49e8e0b6c2b..72de5cc8ad6 100644 --- a/libiberty/sha1.c +++ b/libiberty/sha1.c @@ -234,7 +234,17 @@ sha1_process_bytes (const void *buffer, size_t len, struct sha1_ctx *ctx) 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 (sha1_uint32) != 0) if (UNALIGNED_P (buffer)) while (len > 64)