Andrew Geissler | 6aa7eec | 2023-03-03 12:41:14 -0600 | [diff] [blame^] | 1 | From e649db1664af981cc87f966aef6c5365ae234547 Mon Sep 17 00:00:00 2001 |
Patrick Williams | b9af875 | 2023-01-30 13:28:01 -0600 | [diff] [blame] | 2 | From: Khem Raj <raj.khem@gmail.com> |
| 3 | Date: Sun, 15 Jan 2023 00:16:25 -0800 |
Andrew Geissler | 6aa7eec | 2023-03-03 12:41:14 -0600 | [diff] [blame^] | 4 | Subject: [PATCH] Define alignof using _Alignof when using C11 or newer |
Patrick Williams | b9af875 | 2023-01-30 13:28:01 -0600 | [diff] [blame] | 5 | |
| 6 | WG14 N2350 made very clear that it is an UB having type definitions |
| 7 | within "offsetof" [1]. This patch enhances the implementation of macro |
Andrew Geissler | 6aa7eec | 2023-03-03 12:41:14 -0600 | [diff] [blame^] | 8 | alignof to use builtin "_Alignof" to avoid undefined behavior on |
Patrick Williams | b9af875 | 2023-01-30 13:28:01 -0600 | [diff] [blame] | 9 | when using std=c11 or newer |
| 10 | |
| 11 | clang 16+ has started to flag this [2] |
| 12 | |
| 13 | Fixes build when using -std >= gnu11 and using clang16+ |
| 14 | |
| 15 | Older compilers gcc < 4.9 or clang < 8 has buggy _Alignof even though it |
| 16 | may support C11, exclude those compilers too |
| 17 | |
Patrick Williams | b9af875 | 2023-01-30 13:28:01 -0600 | [diff] [blame] | 18 | [1] https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm |
| 19 | [2] https://reviews.llvm.org/D133574 |
Patrick Williams | b9af875 | 2023-01-30 13:28:01 -0600 | [diff] [blame] | 20 | |
Andrew Geissler | 6aa7eec | 2023-03-03 12:41:14 -0600 | [diff] [blame^] | 21 | Upstream-Status: Pending |
Patrick Williams | b9af875 | 2023-01-30 13:28:01 -0600 | [diff] [blame] | 22 | Signed-off-by: Khem Raj <raj.khem@gmail.com> |
| 23 | --- |
| 24 | libiberty/sha1.c | 10 ++++++++++ |
| 25 | 1 file changed, 10 insertions(+) |
| 26 | |
| 27 | diff --git a/libiberty/sha1.c b/libiberty/sha1.c |
| 28 | index 504f06d3b9b..790ada82443 100644 |
| 29 | --- a/libiberty/sha1.c |
| 30 | +++ b/libiberty/sha1.c |
| 31 | @@ -229,7 +229,17 @@ sha1_process_bytes (const void *buffer, size_t len, struct sha1_ctx *ctx) |
| 32 | if (len >= 64) |
| 33 | { |
| 34 | #if !_STRING_ARCH_unaligned |
| 35 | +/* GCC releases before GCC 4.9 had a bug in _Alignof. See GCC bug 52023 |
| 36 | + <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52023>. |
| 37 | + clang versions < 8.0.0 have the same bug. */ |
| 38 | +#if (!defined __STDC_VERSION__ || __STDC_VERSION__ < 201112 \ |
| 39 | + || (defined __GNUC__ && __GNUC__ < 4 + (__GNUC_MINOR__ < 9) \ |
| 40 | + && !defined __clang__) \ |
| 41 | + || (defined __clang__ && __clang_major__ < 8)) |
| 42 | # define alignof(type) offsetof (struct { char c; type x; }, x) |
| 43 | +#else |
| 44 | +# define alignof(type) _Alignof(type) |
| 45 | +#endif |
| 46 | # define UNALIGNED_P(p) (((size_t) p) % alignof (sha1_uint32) != 0) |
| 47 | if (UNALIGNED_P (buffer)) |
| 48 | while (len > 64) |