Andrew Geissler | c5535c9 | 2023-01-27 16:10:19 -0600 | [diff] [blame^] | 1 | From 9e9d94566d39eef3e4606f806aa418bf5534fab9 Mon Sep 17 00:00:00 2001 |
| 2 | From: Khem Raj <raj.khem@gmail.com> |
| 3 | Date: Sun, 15 Jan 2023 22:04:31 -0800 |
| 4 | Subject: [PATCH 1/2] 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 | |
| 23 | Signed-off-by: Khem Raj <raj.khem@gmail.com> |
| 24 | --- |
| 25 | Misc/md5-coreutils.c | 12 +++++++++++- |
| 26 | Misc/sha1.c | 12 +++++++++++- |
| 27 | Misc/sha256.c | 12 +++++++++++- |
| 28 | Misc/sha512.c | 12 +++++++++++- |
| 29 | 4 files changed, 44 insertions(+), 4 deletions(-) |
| 30 | |
| 31 | diff --git a/Misc/md5-coreutils.c b/Misc/md5-coreutils.c |
| 32 | index d6503e02..2ffb6050 100644 |
| 33 | --- a/Misc/md5-coreutils.c |
| 34 | +++ b/Misc/md5-coreutils.c |
| 35 | @@ -154,7 +154,17 @@ md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx) |
| 36 | if (len >= 64) |
| 37 | { |
| 38 | #if !_STRING_ARCH_unaligned |
| 39 | -# define alignof(type) offsetof (struct { char c; type x; }, x) |
| 40 | +/* GCC releases before GCC 4.9 had a bug in _Alignof. See GCC bug 52023 |
| 41 | + <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52023>. |
| 42 | + clang versions < 8.0.0 have the same bug. */ |
| 43 | +# if (!defined __STDC_VERSION__ || __STDC_VERSION__ < 201112 \ |
| 44 | + || (defined __GNUC__ && __GNUC__ < 4 + (__GNUC_MINOR__ < 9) \ |
| 45 | + && !defined __clang__) \ |
| 46 | + || (defined __clang__ && __clang_major__ < 8)) |
| 47 | +# define alignof(type) offsetof (struct { char c; type x; }, x) |
| 48 | +# else |
| 49 | +# define alignof(type) _Alignof(type) |
| 50 | +# endif |
| 51 | # define UNALIGNED_P(p) (((size_t) p) % alignof (uint32_t) != 0) |
| 52 | if (UNALIGNED_P (buffer)) |
| 53 | while (len > 64) |
| 54 | diff --git a/Misc/sha1.c b/Misc/sha1.c |
| 55 | index 18ceb845..a170efe3 100644 |
| 56 | --- a/Misc/sha1.c |
| 57 | +++ b/Misc/sha1.c |
| 58 | @@ -149,7 +149,17 @@ sha1_process_bytes (const void *buffer, size_t len, struct sha1_ctx *ctx) |
| 59 | if (len >= 64) |
| 60 | { |
| 61 | #if !_STRING_ARCH_unaligned |
| 62 | -# define alignof(type) offsetof (struct { char c; type x; }, x) |
| 63 | +/* GCC releases before GCC 4.9 had a bug in _Alignof. See GCC bug 52023 |
| 64 | + <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52023>. |
| 65 | + clang versions < 8.0.0 have the same bug. */ |
| 66 | +# if (!defined __STDC_VERSION__ || __STDC_VERSION__ < 201112 \ |
| 67 | + || (defined __GNUC__ && __GNUC__ < 4 + (__GNUC_MINOR__ < 9) \ |
| 68 | + && !defined __clang__) \ |
| 69 | + || (defined __clang__ && __clang_major__ < 8)) |
| 70 | +# define alignof(type) offsetof (struct { char c; type x; }, x) |
| 71 | +# else |
| 72 | +# define alignof(type) _Alignof(type) |
| 73 | +# endif |
| 74 | # define UNALIGNED_P(p) (((size_t) p) % alignof (uint32_t) != 0) |
| 75 | if (UNALIGNED_P (buffer)) |
| 76 | while (len > 64) |
| 77 | diff --git a/Misc/sha256.c b/Misc/sha256.c |
| 78 | index 68292326..da59e81d 100644 |
| 79 | --- a/Misc/sha256.c |
| 80 | +++ b/Misc/sha256.c |
| 81 | @@ -372,7 +372,17 @@ sha256_process_bytes (const void *buffer, size_t len, struct sha256_ctx *ctx) |
| 82 | if (len >= 64) |
| 83 | { |
| 84 | #if !_STRING_ARCH_unaligned |
| 85 | -# define alignof(type) offsetof (struct { char c; type x; }, x) |
| 86 | +/* GCC releases before GCC 4.9 had a bug in _Alignof. See GCC bug 52023 |
| 87 | + <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52023>. |
| 88 | + clang versions < 8.0.0 have the same bug. */ |
| 89 | +# if (!defined __STDC_VERSION__ || __STDC_VERSION__ < 201112 \ |
| 90 | + || (defined __GNUC__ && __GNUC__ < 4 + (__GNUC_MINOR__ < 9) \ |
| 91 | + && !defined __clang__) \ |
| 92 | + || (defined __clang__ && __clang_major__ < 8)) |
| 93 | +# define alignof(type) offsetof (struct { char c; type x; }, x) |
| 94 | +# else |
| 95 | +# define alignof(type) _Alignof(type) |
| 96 | +# endif |
| 97 | # define UNALIGNED_P(p) (((size_t) p) % alignof (uint32_t) != 0) |
| 98 | if (UNALIGNED_P (buffer)) |
| 99 | while (len > 64) |
| 100 | diff --git a/Misc/sha512.c b/Misc/sha512.c |
| 101 | index db86c659..38e162fc 100644 |
| 102 | --- a/Misc/sha512.c |
| 103 | +++ b/Misc/sha512.c |
| 104 | @@ -190,7 +190,17 @@ sha512_process_bytes (const void *buffer, size_t len, struct sha512_ctx *ctx) |
| 105 | if (len >= 128) |
| 106 | { |
| 107 | #if !_STRING_ARCH_unaligned |
| 108 | -# define alignof(type) offsetof (struct { char c; type x; }, x) |
| 109 | +/* GCC releases before GCC 4.9 had a bug in _Alignof. See GCC bug 52023 |
| 110 | + <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52023>. |
| 111 | + clang versions < 8.0.0 have the same bug. */ |
| 112 | +# if (!defined __STDC_VERSION__ || __STDC_VERSION__ < 201112 \ |
| 113 | + || (defined __GNUC__ && __GNUC__ < 4 + (__GNUC_MINOR__ < 9) \ |
| 114 | + && !defined __clang__) \ |
| 115 | + || (defined __clang__ && __clang_major__ < 8)) |
| 116 | +# define alignof(type) offsetof (struct { char c; type x; }, x) |
| 117 | +# else |
| 118 | +# define alignof(type) _Alignof(type) |
| 119 | +# endif |
| 120 | # define UNALIGNED_P(p) (((size_t) p) % alignof (uint64_t) != 0) |
| 121 | if (UNALIGNED_P (buffer)) |
| 122 | while (len > 128) |
| 123 | -- |
| 124 | 2.39.0 |
| 125 | |