[FFmpeg-devel] [PATCH] Add a compat stdatomic.h implementation based on GCC atomics
Wan-Teh Chang
wtc at google.com
Mon Nov 28 23:24:22 EET 2016
From: Anton Khirnov <anton at khirnov.net>
Adapted from the code by Rémi Denis-Courmont from VLC
This merges libav commit 4e928ef340ac20325f529d92fcbc51e768085358.
Signed-off-by: Wan-Teh Chang <wtc at google.com>
---
compat/atomics/gcc/stdatomic.h | 173 +++++++++++++++++++++++++++++++++++++++++
configure | 6 ++
2 files changed, 179 insertions(+)
create mode 100644 compat/atomics/gcc/stdatomic.h
diff --git a/compat/atomics/gcc/stdatomic.h b/compat/atomics/gcc/stdatomic.h
new file mode 100644
index 0000000..41cadde
--- /dev/null
+++ b/compat/atomics/gcc/stdatomic.h
@@ -0,0 +1,173 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/*
+ * based on vlc_atomic.h from VLC
+ * Copyright (C) 2010 Rémi Denis-Courmont
+ */
+
+#ifndef COMPAT_ATOMICS_GCC_STDATOMIC_H
+#define COMPAT_ATOMICS_GCC_STDATOMIC_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#define ATOMIC_FLAG_INIT 0
+
+#define ATOMIC_VAR_INIT(value) (value)
+
+#define atomic_init(obj, value) \
+do { \
+ *(obj) = (value); \
+} while(0)
+
+#define kill_dependency(y) ((void)0)
+
+#define atomic_thread_fence(order) \
+ __sync_synchronize()
+
+#define atomic_signal_fence(order) \
+ ((void)0)
+
+#define atomic_is_lock_free(obj) 0
+
+typedef _Bool atomic_flag;
+typedef _Bool atomic_bool;
+typedef char atomic_char;
+typedef signed char atomic_schar;
+typedef unsigned char atomic_uchar;
+typedef short atomic_short;
+typedef unsigned short atomic_ushort;
+typedef int atomic_int;
+typedef unsigned int atomic_uint;
+typedef long atomic_long;
+typedef unsigned long atomic_ulong;
+typedef long long atomic_llong;
+typedef unsigned long long atomic_ullong;
+typedef wchar_t atomic_wchar_t;
+typedef int_least8_t atomic_int_least8_t;
+typedef uint_least8_t atomic_uint_least8_t;
+typedef int_least16_t atomic_int_least16_t;
+typedef uint_least16_t atomic_uint_least16_t;
+typedef int_least32_t atomic_int_least32_t;
+typedef uint_least32_t atomic_uint_least32_t;
+typedef int_least64_t atomic_int_least64_t;
+typedef uint_least64_t atomic_uint_least64_t;
+typedef int_fast8_t atomic_int_fast8_t;
+typedef uint_fast8_t atomic_uint_fast8_t;
+typedef int_fast16_t atomic_int_fast16_t;
+typedef uint_fast16_t atomic_uint_fast16_t;
+typedef int_fast32_t atomic_int_fast32_t;
+typedef uint_fast32_t atomic_uint_fast32_t;
+typedef int_fast64_t atomic_int_fast64_t;
+typedef uint_fast64_t atomic_uint_fast64_t;
+typedef intptr_t atomic_intptr_t;
+typedef uintptr_t atomic_uintptr_t;
+typedef size_t atomic_size_t;
+typedef ptrdiff_t atomic_ptrdiff_t;
+typedef intmax_t atomic_intmax_t;
+typedef uintmax_t atomic_uintmax_t;
+
+#define atomic_store(object, desired) \
+do { \
+ *(object) = (desired); \
+ __sync_synchronize(); \
+} while (0)
+
+#define atomic_store_explicit(object, desired, order) \
+ atomic_store(object, desired)
+
+#define atomic_load(object) \
+ (__sync_synchronize(), *(object))
+
+#define atomic_load_explicit(object, order) \
+ atomic_load(object)
+
+#define atomic_exchange(object, desired) \
+({ \
+ typeof(object) _obj = (object); \
+ typeof(*object) _old; \
+ do \
+ _old = atomic_load(_obj); \
+ while (!__sync_bool_compare_and_swap(_obj, _old, (desired))); \
+ _old; \
+})
+
+#define atomic_exchange_explicit(object, desired, order) \
+ atomic_exchange(object, desired)
+
+#define atomic_compare_exchange_strong(object, expected, desired) \
+({ \
+ typeof(object) _exp = (expected); \
+ typeof(*object) _old = *_exp; \
+ *_exp = __sync_val_compare_and_swap((object), _old, (desired)); \
+ *_exp == _old; \
+})
+
+#define atomic_compare_exchange_strong_explicit(object, expected, desired, success, failure) \
+ atomic_compare_exchange_strong(object, expected, desired)
+
+#define atomic_compare_exchange_weak(object, expected, desired) \
+ atomic_compare_exchange_strong(object, expected, desired)
+
+#define atomic_compare_exchange_weak_explicit(object, expected, desired, success, failure) \
+ atomic_compare_exchange_weak(object, expected, desired)
+
+#define atomic_fetch_add(object, operand) \
+ __sync_fetch_and_add(object, operand)
+
+#define atomic_fetch_add_explicit(object, operand, order) \
+ atomic_fetch_add(object, operand)
+
+#define atomic_fetch_sub(object, operand) \
+ __sync_fetch_and_sub(object, operand)
+
+#define atomic_fetch_sub_explicit(object, operand, order) \
+ atomic_fetch_sub(object, operand)
+
+#define atomic_fetch_or(object, operand) \
+ __sync_fetch_and_or(object, operand)
+
+#define atomic_fetch_or_explicit(object, operand, order) \
+ atomic_fetch_or(object, operand)
+
+#define atomic_fetch_xor(object, operand) \
+ __sync_fetch_and_sub(object, operand)
+
+#define atomic_fetch_xor_explicit(object, operand, order) \
+ atomic_fetch_sub(object, operand)
+
+#define atomic_fetch_and(object, operand) \
+ __sync_fetch_and_and(object, operand)
+
+#define atomic_fetch_and_explicit(object, operand, order) \
+ atomic_fetch_and(object, operand)
+
+#define atomic_flag_test_and_set(object) \
+ atomic_exchange(object, 1)
+
+#define atomic_flag_test_and_set_explicit(object, order) \
+ atomic_flag_test_and_set(object)
+
+#define atomic_flag_clear(object) \
+ atomic_store(object, 0)
+
+#define atomic_flag_clear_explicit(object, order) \
+ atomic_flag_clear(object)
+
+#endif /* COMPAT_ATOMICS_GCC_STDATOMIC_H */
diff --git a/configure b/configure
index 6345fc2..8cbe6f8 100755
--- a/configure
+++ b/configure
@@ -6381,6 +6381,12 @@ for thread in $THREADS_LIST; do
fi
done
+if disabled stdatomic_h; then
+ if enabled atomics_gcc; then
+ add_cppflags '-I\$(SRC_PATH)/compat/atomics/gcc'
+ fi
+fi
+
enabled zlib && add_cppflags -DZLIB_CONST
# conditional library dependencies, in linking order
--
2.8.0.rc3.226.g39d4020
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