svn commit: r228862 - head/include
David Chisnall
theraven at FreeBSD.org
Sat Dec 24 15:17:02 UTC 2011
Author: theraven
Date: Sat Dec 24 15:17:01 2011
New Revision: 228862
URL: http://svn.freebsd.org/changeset/base/228862
Log:
Initial implementation of stdatomic.h. Works (at least in the parts that were
tested) with clang and gcc, and more efficiently with clang+a big out-of-tree
diff that I need to commit soon (once it's been tidied and reviewed a bit).
Large portions by: ed
Reviewed by: ed
Approved by: dim (mentor)
Added:
head/include/stdatomic.h (contents, props changed)
Added: head/include/stdatomic.h
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ head/include/stdatomic.h Sat Dec 24 15:17:01 2011 (r228862)
@@ -0,0 +1,296 @@
+/*-
+ * Copyright (c) 2011 Ed Schouten <ed at FreeBSD.org>
+ * David Chisnall <theraven at FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _STDATOMIC_H_
+#define _STDATOMIC_H_
+
+#include <sys/cdefs.h>
+#include <sys/_types.h>
+
+#if __has_feature(cxx_atomic)
+#define __CLANG_ATOMICS
+#elif defined(__GNUC__)
+#define __GNUC_ATOMICS
+#else
+#error "stdatomic.h does not support your compiler"
+#endif
+
+#ifdef __GNUC_ATOMICS
+#define _Atomic(T) struct { volatile T __val; }
+#endif
+
+/*
+ * 7.17.2 Initialization.
+ */
+
+#if defined(__CLANG_ATOMICS)
+#define ATOMIC_VAR_INIT(value) (value)
+#define atomic_init(obj, value) __atomic_init(obj, value)
+#elif defined(__GNUC_ATOMICS)
+#define ATOMIC_VAR_INIT(value) { .__val = (value) }
+#define atomic_init(obj, value) (obj = ATOMIC_VAR_INIT(value))
+#endif
+
+/*
+ * Clang and recent GCC both provide predefined macros for the memory
+ * orderings. If we are using a compiler that doesn't define them, use the
+ * clang values - these will be ignored in the fallback path.
+ */
+
+#ifndef __ATOMIC_RELAXED
+#define __ATOMIC_RELAXED 0
+#endif
+#ifndef __ATOMIC_CONSUME
+#define __ATOMIC_CONSUME 1
+#endif
+#ifndef __ATOMIC_ACQUIRE
+#define __ATOMIC_ACQUIRE 2
+#endif
+#ifndef __ATOMIC_RELEASE
+#define __ATOMIC_RELEASE 3
+#endif
+#ifndef __ATOMIC_ACQ_REL
+#define __ATOMIC_ACQ_REL 4
+#endif
+#ifndef __ATOMIC_SEQ_CST
+#define __ATOMIC_SEQ_CST 5
+#endif
+
+/*
+ * 7.17.3 Order and consistency.
+ *
+ * The memory_order_* constants that denote the barrier behaviour of the
+ * atomic operations.
+ */
+
+enum memory_order {
+ memory_order_relaxed = __ATOMIC_RELAXED,
+ memory_order_consume = __ATOMIC_CONSUME,
+ memory_order_acquire = __ATOMIC_ACQUIRE,
+ memory_order_release = __ATOMIC_RELEASE,
+ memory_order_acq_rel = __ATOMIC_ACQ_REL,
+ memory_order_seq_cst = __ATOMIC_SEQ_CST
+};
+
+/*
+ * 7.17.4 Fences.
+ */
+
+#if defined(__CLANG_ATOMICS)
+#define atomic_thread_fence(order) __atomic_thread_fence(order)
+#elif defined(__GNUC_ATOMICS)
+#define atomic_thread_fence(order) __sync_synchronize()
+#endif
+#define atomic_signal_fence(order) __asm volatile ("" : : : "memory");
+
+/*
+ * 7.17.5 Lock-free property.
+ */
+
+#if defined(__CLANG_ATOMICS)
+#define atomic_is_lock_free(obj) __atomic_is_lock_free(obj)
+#elif defined(__GNUC_ATOMICS)
+#define atomic_is_lock_free(obj) (sizeof((obj->__val)) <= sizeof(void *))
+#endif
+
+/*
+ * 7.17.6 Atomic integer types.
+ */
+
+typedef _Atomic(_Bool) atomic_bool;
+typedef _Atomic(char) atomic_char;
+typedef _Atomic(signed char) atomic_schar;
+typedef _Atomic(unsigned char) atomic_uchar;
+typedef _Atomic(short) atomic_short;
+typedef _Atomic(unsigned short) atomic_ushort;
+typedef _Atomic(int) atomic_int;
+typedef _Atomic(unsigned int) atomic_uint;
+typedef _Atomic(long) atomic_long;
+typedef _Atomic(unsigned long) atomic_ulong;
+typedef _Atomic(long long) atomic_llong;
+typedef _Atomic(unsigned long long) atomic_ullong;
+#if 0
+typedef _Atomic(__char16_t) atomic_char16_t;
+typedef _Atomic(__char32_t) atomic_char32_t;
+#endif
+typedef _Atomic(__wchar_t) atomic_wchar_t;
+typedef _Atomic(__int_least8_t) atomic_int_least8_t;
+typedef _Atomic(__uint_least8_t) atomic_uint_least8_t;
+typedef _Atomic(__int_least16_t) atomic_int_least16_t;
+typedef _Atomic(__uint_least16_t) atomic_uint_least16_t;
+typedef _Atomic(__int_least32_t) atomic_int_least32_t;
+typedef _Atomic(__uint_least32_t) atomic_uint_least32_t;
+typedef _Atomic(__int_least64_t) atomic_int_least64_t;
+typedef _Atomic(__uint_least64_t) atomic_uint_least64_t;
+typedef _Atomic(__int_fast8_t) atomic_int_fast8_t;
+typedef _Atomic(__uint_fast8_t) atomic_uint_fast8_t;
+typedef _Atomic(__int_fast16_t) atomic_int_fast16_t;
+typedef _Atomic(__uint_fast16_t) atomic_uint_fast16_t;
+typedef _Atomic(__int_fast32_t) atomic_int_fast32_t;
+typedef _Atomic(__uint_fast32_t) atomic_uint_fast32_t;
+typedef _Atomic(__int_fast64_t) atomic_int_fast64_t;
+typedef _Atomic(__uint_fast64_t) atomic_uint_fast64_t;
+typedef _Atomic(__intptr_t) atomic_intptr_t;
+typedef _Atomic(__uintptr_t) atomic_uintptr_t;
+typedef _Atomic(__size_t) atomic_size_t;
+typedef _Atomic(__ptrdiff_t) atomic_ptrdiff_t;
+typedef _Atomic(__intmax_t) atomic_intmax_t;
+typedef _Atomic(__uintmax_t) atomic_uintmax_t;
+
+/*
+ * 7.17.7 Operations on atomic types.
+ */
+
+/*
+ * Compiler-specific operations.
+ */
+
+#if defined(__CLANG_ATOMICS)
+#define atomic_compare_exchange_strong_explicit(object, expected, \
+ desired, success, failure) \
+ __atomic_compare_exchange_strong(object, expected, desired, \
+ success, failure)
+#define atomic_compare_exchange_weak_explicit(object, expected, \
+ desired, success, failure) \
+ __atomic_compare_exchange_weak(object, expected, desired, \
+ success, failure)
+#define atomic_exchange_explicit(object, desired, order) \
+ __atomic_exchange(object, desired, order)
+#define atomic_fetch_add_explicit(object, operand, order) \
+ __atomic_fetch_add(object, operand, order)
+#define atomic_fetch_and_explicit(object, operand, order) \
+ __atomic_fetch_and(object, operand, order)
+#define atomic_fetch_or_explicit(object, operand, order) \
+ __atomic_fetch_or(object, operand, order)
+#define atomic_fetch_sub_explicit(object, operand, order) \
+ __atomic_fetch_sub(object, operand, order)
+#define atomic_fetch_xor_explicit(object, operand, order) \
+ __atomic_fetch_xor(object, operand, order)
+#define atomic_load_explicit(object, order) \
+ __atomic_load(object, order)
+#define atomic_store_explicit(object, desired, order) \
+ __atomic_store(object, desired, order)
+#elif defined(__GNUC_ATOMICS)
+#define atomic_compare_exchange_strong_explicit(object, expected, \
+ desired, success, failure) ({ \
+ __typeof__((object)->__val) __v; \
+ __v = \
+ __sync_val_compare_and_swap((__typeof(&((object)->__val)))object,\
+ *expected, desired); \
+ *expected = __v; \
+ (*expected == __v); \
+ })
+
+#define atomic_compare_exchange_weak_explicit(object, expected, \
+ desired, success, failure) \
+ atomic_compare_exchange_strong_explicit(object, expected, \
+ desired, success, failure)
+#if __has_builtin(__sync_swap)
+/* Clang provides a full-barrier atomic exchange - use it if available. */
+#define atomic_exchange_explicit(object, desired, order) \
+ __sync_swap(&(object)->value, desired)
+#else
+/*
+ * __sync_lock_test_and_set() is only an acquire barrier in theory (although in
+ * practice it is usually a full barrier) so we need an explicit barrier after
+ * it.
+ */
+#define atomic_exchange_explicit(object, desired, order) ({ \
+ __typeof__((object)->__val) __v; \
+ __v = __sync_lock_test_and_set(object, desired); \
+ __sync_synchronize(); \
+ __v; \
+})
+#endif
+#define atomic_fetch_add_explicit(object, operand, order) \
+ __sync_fetch_and_add(&(object)->__val, operand)
+#define atomic_fetch_and_explicit(object, operand, order) \
+ __sync_fetch_and_and(&(object)->__val, operand)
+#define atomic_fetch_or_explicit(object, operand, order) \
+ __sync_fetch_and_or(&(object)->__val, operand)
+#define atomic_fetch_sub_explicit(object, operand, order) \
+ __sync_fetch_and_sub(&(object)->__val, operand)
+#define atomic_fetch_xor_explicit(object, operand, order) \
+ __sync_fetch_and_xor(&(object)->__val, operand)
+#define atomic_load_explicit(object, order) \
+ __sync_fetch_and_add(&(object)->__val, 0)
+#define atomic_store_explicit(object, desired, order) do { \
+ __sync_synchronize(); \
+ (object)->__val = (desired); \
+ __sync_synchronize(); \
+} while (0)
+#endif
+
+/*
+ * Convenience functions.
+ */
+
+#define atomic_compare_exchange_strong(object, expected, desired) \
+ atomic_compare_exchange_strong_explicit(object, expected, \
+ desired, memory_order_seq_cst, memory_order_seq_cst)
+#define atomic_compare_exchange_weak(object, expected, desired) \
+ atomic_compare_exchange_weak_explicit(object, expected, \
+ desired, memory_order_seq_cst, memory_order_seq_cst)
+#define atomic_exchange(object, desired) \
+ atomic_exchange_explicit(object, desired, memory_order_seq_cst)
+#define atomic_fetch_add(object, operand) \
+ atomic_fetch_add_explicit(object, operand, memory_order_seq_cst)
+#define atomic_fetch_and(object, operand) \
+ atomic_fetch_and_explicit(object, operand, memory_order_seq_cst)
+#define atomic_fetch_or(object, operand) \
+ atomic_fetch_or_explicit(object, operand, memory_order_seq_cst)
+#define atomic_fetch_sub(object, operand) \
+ atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst)
+#define atomic_fetch_xor(object, operand) \
+ atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst)
+#define atomic_load(object) \
+ atomic_load_explicit(object, memory_order_seq_cst)
+#define atomic_store(object, desired) \
+ atomic_store_explicit(object, desired, memory_order_seq_cst)
+
+/*
+ * 7.17.8 Atomic flag type and operations.
+ */
+
+typedef atomic_bool atomic_flag;
+
+#define ATOMIC_FLAG_INIT ATOMIC_VAR_INIT(0)
+
+#define atomic_flag_clear_explicit(object, order) \
+ atomic_store_explicit(object, 0, order)
+#define atomic_flag_test_and_set_explicit(object, order) \
+ atomic_compare_exchange_strong_explicit(object, 0, 1, order, order)
+
+#define atomic_flag_clear(object) \
+ atomic_flag_clear_explicit(object, 0, memory_order_seq_cst)
+#define atomic_flag_test_and_set(object) \
+ atomic_flag_test_and_set_explicit(object, 0, 1, \
+ memory_order_seq_cst, memory_order_seq_cst)
+
+#endif /* !_STDATOMIC_H_ */
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