Emulate clang atomic built-ins on gcc > 4.7 gcc 4.7 and above has atomic built-ins which slightly different APIs from those provided by clang. Add proxy functions that wrap the gcc built-ins to produce a symbol that is API equivalent to the clang built-ins. This allows libc++'s atomic library to be used with gcc-4.7 and newer. Patch contributed by Albert Wong. git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@215305 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/atomic b/include/atomic index f6ab1cb..91f1829 100644 --- a/include/atomic +++ b/include/atomic
@@ -535,7 +535,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD -#if !__has_feature(cxx_atomic) +#if !__has_feature(cxx_atomic) && _GNUC_VER < 407 #error <atomic> is not implemented #else @@ -545,6 +545,257 @@ memory_order_release, memory_order_acq_rel, memory_order_seq_cst } memory_order; +#if _GNUC_VER >= 407 +namespace __gcc_atomic { +template <typename T> +struct __gcc_atomic_t { + __gcc_atomic_t() _NOEXCEPT {} + explicit __gcc_atomic_t(T value) _NOEXCEPT : __a_value(value) {} + T __a_value; +}; +#define _Atomic(x) __gcc_atomic::__gcc_atomic_t<x> + +template <typename T> T __create(); + +template <typename __Tp, typename __Td> +typename enable_if<sizeof(__Tp()->__a_value = __create<__Td>()), char>::type + __test_atomic_assignable(int); +template <typename T, typename U> +__two __test_atomic_assignable(...); + +template <typename __Tp, typename __Td> +struct __can_assign { + static const bool value = + sizeof(__test_atomic_assignable<__Tp, __Td>(1)) == sizeof(char); +}; + +static inline constexpr int __to_gcc_order(memory_order __order) { + // Avoid switch statement to make this a constexpr. + return __order == memory_order_relaxed ? __ATOMIC_RELAXED: + (__order == memory_order_acquire ? __ATOMIC_ACQUIRE: + (__order == memory_order_release ? __ATOMIC_RELEASE: + (__order == memory_order_seq_cst ? __ATOMIC_SEQ_CST: + (__order == memory_order_acq_rel ? __ATOMIC_ACQ_REL: + __ATOMIC_CONSUME)))); +} + +} // namespace __gcc_atomic + +template <typename _Tp> +static inline +typename enable_if< + __gcc_atomic::__can_assign<volatile _Atomic(_Tp)*, _Tp>::value>::type +__c11_atomic_init(volatile _Atomic(_Tp)* __a, _Tp __val) { + __a->__a_value = __val; +} + +template <typename _Tp> +static inline +typename enable_if< + !__gcc_atomic::__can_assign<volatile _Atomic(_Tp)*, _Tp>::value && + __gcc_atomic::__can_assign< _Atomic(_Tp)*, _Tp>::value>::type +__c11_atomic_init(volatile _Atomic(_Tp)* __a, _Tp __val) { + // [atomics.types.generic]p1 guarantees _Tp is trivially copyable. Because + // the default operator= in an object is not volatile, a byte-by-byte copy + // is required. + volatile char* to = reinterpret_cast<volatile char*>(&__a->__a_value); + volatile char* end = to + sizeof(_Tp); + char* from = reinterpret_cast<char*>(&__val); + while (to != end) { + *to++ = *from++; + } +} + +template <typename _Tp> +static inline void __c11_atomic_init(_Atomic(_Tp)* __a, _Tp __val) { + __a->__a_value = __val; +} + +static inline void __c11_atomic_thread_fence(memory_order __order) { + __atomic_thread_fence(__gcc_atomic::__to_gcc_order(__order)); +} + +static inline void __c11_atomic_signal_fence(memory_order __order) { + __atomic_signal_fence(__gcc_atomic::__to_gcc_order(__order)); +} + +static inline bool __c11_atomic_is_lock_free(size_t __size) { + return __atomic_is_lock_free(__size, 0); +} + +template <typename _Tp> +static inline void __c11_atomic_store(volatile _Atomic(_Tp)* __a, _Tp __val, + memory_order __order) { + return __atomic_store(&__a->__a_value, &__val, + __gcc_atomic::__to_gcc_order(__order)); +} + +template <typename _Tp> +static inline void __c11_atomic_store(_Atomic(_Tp)* __a, _Tp __val, + memory_order __order) { + return __atomic_store(&__a->__a_value, &__val, + __gcc_atomic::__to_gcc_order(__order)); +} + +template <typename _Tp> +static inline _Tp __c11_atomic_load(volatile _Atomic(_Tp)* __a, + memory_order __order) { + _Tp __ret; + __atomic_load(&__a->__a_value, &__ret, + __gcc_atomic::__to_gcc_order(__order)); + return __ret; +} + +template <typename _Tp> +static inline _Tp __c11_atomic_load(_Atomic(_Tp)* __a, memory_order __order) { + _Tp __ret; + __atomic_load(&__a->__a_value, &__ret, + __gcc_atomic::__to_gcc_order(__order)); + return __ret; +} + +template <typename _Tp> +static inline _Tp __c11_atomic_exchange(volatile _Atomic(_Tp)* __a, + _Tp __value, memory_order __order) { + _Tp __ret; + __atomic_exchange(&__a->__a_value, &__value, &__ret, + __gcc_atomic::__to_gcc_order(__order)); + return __ret; +} + +template <typename _Tp> +static inline _Tp __c11_atomic_exchange(_Atomic(_Tp)* __a, _Tp __value, + memory_order __order) { + _Tp __ret; + __atomic_exchange(&__a->__a_value, &__value, &__ret, + __gcc_atomic::__to_gcc_order(__order)); + return __ret; +} + +template <typename _Tp> +static inline bool __c11_atomic_compare_exchange_strong( + volatile _Atomic(_Tp)* __a, _Tp* __expected, _Tp __value, + memory_order __success, memory_order __failure) { + return __atomic_compare_exchange(&__a->__a_value, __expected, &__value, + false, + __gcc_atomic::__to_gcc_order(__success), + __gcc_atomic::__to_gcc_order(__failure)); +} + +template <typename _Tp> +static inline bool __c11_atomic_compare_exchange_strong( + _Atomic(_Tp)* __a, _Tp* __expected, _Tp __value, memory_order __success, + memory_order __failure) { + return __atomic_compare_exchange(&__a->__a_value, __expected, &__value, + false, + __gcc_atomic::__to_gcc_order(__success), + __gcc_atomic::__to_gcc_order(__failure)); +} + +template <typename _Tp> +static inline bool __c11_atomic_compare_exchange_weak( + volatile _Atomic(_Tp)* __a, _Tp* __expected, _Tp __value, + memory_order __success, memory_order __failure) { + return __atomic_compare_exchange(&__a->__a_value, __expected, &__value, + true, + __gcc_atomic::__to_gcc_order(__success), + __gcc_atomic::__to_gcc_order(__failure)); +} + +template <typename _Tp> +static inline bool __c11_atomic_compare_exchange_weak( + _Atomic(_Tp)* __a, _Tp* __expected, _Tp __value, memory_order __success, + memory_order __failure) { + return __atomic_compare_exchange(&__a->__a_value, __expected, &__value, + true, + __gcc_atomic::__to_gcc_order(__success), + __gcc_atomic::__to_gcc_order(__failure)); +} + +template <typename _Tp> +struct __skip_amt { enum {value = 1}; }; + +template <typename _Tp> +struct __skip_amt<_Tp*> { enum {value = sizeof(_Tp)}; }; + +// FIXME: Haven't figured out what the spec says about using arrays with +// atomic_fetch_add. Force a failure rather than creating bad behavior. +template <typename _Tp> +struct __skip_amt<_Tp[]> { }; +template <typename _Tp, int n> +struct __skip_amt<_Tp[n]> { }; + +template <typename _Tp, typename _Td> +static inline _Tp __c11_atomic_fetch_add(volatile _Atomic(_Tp)* __a, + _Td __delta, memory_order __order) { + return __atomic_fetch_add(&__a->__a_value, __delta * __skip_amt<_Tp>::value, + __gcc_atomic::__to_gcc_order(__order)); +} + +template <typename _Tp, typename _Td> +static inline _Tp __c11_atomic_fetch_add(_Atomic(_Tp)* __a, _Td __delta, + memory_order __order) { + return __atomic_fetch_add(&__a->__a_value, __delta * __skip_amt<_Tp>::value, + __gcc_atomic::__to_gcc_order(__order)); +} + +template <typename _Tp, typename _Td> +static inline _Tp __c11_atomic_fetch_sub(volatile _Atomic(_Tp)* __a, + _Td __delta, memory_order __order) { + return __atomic_fetch_sub(&__a->__a_value, __delta * __skip_amt<_Tp>::value, + __gcc_atomic::__to_gcc_order(__order)); +} + +template <typename _Tp, typename _Td> +static inline _Tp __c11_atomic_fetch_sub(_Atomic(_Tp)* __a, _Td __delta, + memory_order __order) { + return __atomic_fetch_sub(&__a->__a_value, __delta * __skip_amt<_Tp>::value, + __gcc_atomic::__to_gcc_order(__order)); +} + +template <typename _Tp> +static inline _Tp __c11_atomic_fetch_and(volatile _Atomic(_Tp)* __a, + _Tp __pattern, memory_order __order) { + return __atomic_fetch_and(&__a->__a_value, __pattern, + __gcc_atomic::__to_gcc_order(__order)); +} + +template <typename _Tp> +static inline _Tp __c11_atomic_fetch_and(_Atomic(_Tp)* __a, + _Tp __pattern, memory_order __order) { + return __atomic_fetch_and(&__a->__a_value, __pattern, + __gcc_atomic::__to_gcc_order(__order)); +} + +template <typename _Tp> +static inline _Tp __c11_atomic_fetch_or(volatile _Atomic(_Tp)* __a, + _Tp __pattern, memory_order __order) { + return __atomic_fetch_or(&__a->__a_value, __pattern, + __gcc_atomic::__to_gcc_order(__order)); +} + +template <typename _Tp> +static inline _Tp __c11_atomic_fetch_or(_Atomic(_Tp)* __a, _Tp __pattern, + memory_order __order) { + return __atomic_fetch_or(&__a->__a_value, __pattern, + __gcc_atomic::__to_gcc_order(__order)); +} + +template <typename _Tp> +static inline _Tp __c11_atomic_fetch_xor(volatile _Atomic(_Tp)* __a, + _Tp __pattern, memory_order __order) { + return __atomic_fetch_xor(&__a->__a_value, __pattern, + __gcc_atomic::__to_gcc_order(__order)); +} + +template <typename _Tp> +static inline _Tp __c11_atomic_fetch_xor(_Atomic(_Tp)* __a, _Tp __pattern, + memory_order __order) { + return __atomic_fetch_xor(&__a->__a_value, __pattern, + __gcc_atomic::__to_gcc_order(__order)); +} +#endif // _GNUC_VER >= 407 + template <class _Tp> inline _LIBCPP_INLINE_VISIBILITY _Tp 