Commit f225ad7a authored by Derek Buitenhuis's avatar Derek Buitenhuis

Add stdatomic fallback for GCC 4.7/4.8

This compiler version is still shipped with the latest version of
some distros, like RHEL/CentOS, sadly.

This implementation requires on the __atomic functions.
Signed-off-by: Derek Buitenhuis's avatarDerek Buitenhuis <derek.buitenhuis@gmail.com>
parent d253401a
/*
* Copyright © 2018, VideoLAN and dav1d authors
* All rights reserved.
*
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* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
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*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
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*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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#ifndef GCCVER_STDATOMIC_H_
#define GCCVER_STDATOMIC_H_
#if !defined(__cplusplus)
typedef int atomic_int;
typedef unsigned int atomic_uint;
#define memory_order_relaxed __ATOMIC_RELAXED
#define memory_order_acquire __ATOMIC_ACQUIRE
#define atomic_init(p_a, v) do { *(p_a) = (v); } while(0)
#define atomic_store(p_a, v) __atomic_store_n(p_a, v, __ATOMIC_SEQ_CST)
#define atomic_load(p_a) __atomic_load_n(p_a, __ATOMIC_SEQ_CST)
#define atomic_load_explicit(p_a, mo) __atomic_load_n(p_a, mo)
#define atomic_fetch_add(p_a, inc) __atomic_fetch_add(p_a, inc, __ATOMIC_SEQ_CST)
#define atomic_fetch_sub(p_a, dec) __atomic_fetch_sub(p_a, dec, __ATOMIC_SEQ_CST)
#endif /* !defined(__cplusplus) */
#endif /* GCCVER_STDATOMIC_H_ */
......@@ -108,6 +108,11 @@ if not cc.check_header('stdatomic.h')
stdatomic_dependency = declare_dependency(
include_directories : include_directories('include/compat'),
)
elif cc.compiles('''int main() { int v = 0; return __atomic_fetch_add(&v, 1, __ATOMIC_SEQ_CST); }''',
name : 'GCC-style atomics', args : test_args)
stdatomic_dependency = declare_dependency(
include_directories : include_directories('include/compat/gcc'),
)
else
error('Atomics not supported')
endif
......
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