git.ipfire.org Git - thirdparty/openembedded/openembedded-core-contrib.git/blob

   1 From ea68b64a00dd236c6e062a9403bf8a4b2234aaa5 Mon Sep 17 00:00:00 2001
   2 From: Khem Raj <raj.khem@gmail.com>
   3 Date: Sun, 15 Jan 2023 00:16:25 -0800
   4 Subject: [PATCH] Define alignof using _Alignof when using C11 or newer
   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
   8 alignof to use builtin "_Alignof" to avoid undefined behavior on
   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
  18 [1] https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm
  19 [2] https://reviews.llvm.org/D133574
  20
  21 Upstream-Status: Pending
  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 27ceccc027b..a81332972d1 100644
  29 --- a/libiberty/sha1.c
  30 +++ b/libiberty/sha1.c
  31 @@ -234,7 +234,17 @@ 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)