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| author | Tavian Barnes <tavianator@tavianator.com> | 2024-04-19 15:44:36 -0400 |
|---|---|---|
| committer | Tavian Barnes <tavianator@tavianator.com> | 2024-04-19 15:50:45 -0400 |
| commit | 75311e2f9aabd1e4775176e9adff5cd5f1fe42aa (patch) | |
| tree | 11bc6596c2a06e1a5460b1e1628a0380398e0718 | |
| parent | 0d8bf80364a23d9b90ab6c034625b60e4c566c61 (diff) | |
| download | bfs-75311e2f9aabd1e4775176e9adff5cd5f1fe42aa.tar.xz | |
config: Check for max_align_t
| -rw-r--r-- | config/header.mk | 1 | ||||
| -rw-r--r-- | config/max-align-t.c | 8 | ||||
| -rw-r--r-- | src/prelude.h | 19 |
3 files changed, 24 insertions, 4 deletions
diff --git a/config/header.mk b/config/header.mk index 86a4dc5..bba03ef 100644 --- a/config/header.mk +++ b/config/header.mk @@ -18,6 +18,7 @@ HEADERS := \ ${GEN}/getdents64-syscall.h \ ${GEN}/getprogname.h \ ${GEN}/getprogname-gnu.h \ + ${GEN}/max-align-t.h \ ${GEN}/pipe2.h \ ${GEN}/posix-spawn-addfchdir.h \ ${GEN}/posix-spawn-addfchdir-np.h \ diff --git a/config/max-align-t.c b/config/max-align-t.c new file mode 100644 index 0000000..96165ce --- /dev/null +++ b/config/max-align-t.c @@ -0,0 +1,8 @@ +// Copyright © Tavian Barnes <tavianator@tavianator.com> +// SPDX-License-Identifier: 0BSD + +#include <stddef.h> + +int main(void) { + return _Alignof(max_align_t); +} diff --git a/src/prelude.h b/src/prelude.h index a23b167..390666b 100644 --- a/src/prelude.h +++ b/src/prelude.h @@ -182,14 +182,25 @@ extern const char bfs_version[]; #endif /** + * Polyfill max_align_t if we don't already have it. + */ +#if !BFS_HAS_MAX_ALIGN_T +typedef union { +# ifdef __BIGGEST_ALIGNMENT__ + alignas(__BIGGEST_ALIGNMENT__) char c; +# else + long double ld; + long long ll; + void *ptr; +# endif +} max_align_t; +#endif + +/** * Alignment specifier that avoids false sharing. */ #define cache_align alignas(FALSE_SHARING_SIZE) -#if __COSMOPOLITAN__ -typedef long double max_align_t; -#endif - // Wrappers for attributes /** |