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| author | Khem Raj <raj.khem@gmail.com> | 2023-01-18 09:32:36 +0100 |
|---|---|---|
| committer | Jes Sorensen <jes@trained-monkey.org> | 2023-03-19 17:15:52 +0100 |
| commit | 566844b93e6823a04ed65827ba3e03cb123b3a03 (patch) | |
| tree | af1691a2479d5ce9ecbd94d686dac74a43deb982 /sha1.c | |
| parent | manpage: Add --write-zeroes option to manpage (diff) | |
| download | mdadm-566844b93e6823a04ed65827ba3e03cb123b3a03.tar.xz mdadm-566844b93e6823a04ed65827ba3e03cb123b3a03.zip | |
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: Pending
Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Jes Sorensen <jes@trained-monkey.org>
Diffstat (limited to '')
| -rw-r--r-- | sha1.c | 12 |
1 files changed, 11 insertions, 1 deletions
@@ -229,7 +229,17 @@ sha1_process_bytes (const void *buffer, size_t len, struct sha1_ctx *ctx) if (len >= 64) { #if !_STRING_ARCH_unaligned -# define alignof(type) offsetof (struct { char c; type x; }, x) +/* GCC releases before GCC 4.9 had a bug in _Alignof. See GCC bug 52023 + <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=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) |