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[libc++] Change memory_order to an enum class
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This implements P0439R0.

Thanks to Zoe Carver for the patch.
Differential Revision: https://reviews.llvm.org/D58201

llvm-svn: 355403
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@ldionne
ldionne committed Mar 5, 2019
1 parent bc6b225 commit b558032
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Showing 4 changed files with 115 additions and 59 deletions.
132 changes: 82 additions & 50 deletions libcxx/include/atomic
View file
Expand Up @@ -20,17 +20,24 @@ namespace std
#define __cpp_lib_atomic_is_always_lock_free // as specified by SG10
// order and consistency
typedef enum memory_order
{
memory_order_relaxed,
memory_order_consume, // load-consume
memory_order_acquire, // load-acquire
memory_order_release, // store-release
memory_order_acq_rel, // store-release load-acquire
memory_order_seq_cst // store-release load-acquire
} memory_order;
// order and consistency
enum memory_order: unspecified // enum class in C++20
{
relaxed,
consume, // load-consume
acquire, // load-acquire
release, // store-release
acq_rel, // store-release load-acquire
seq_cst // store-release load-acquire
};
inline constexpr auto memory_order_relaxed = memory_order::relaxed;
inline constexpr auto memory_order_consume = memory_order::consume;
inline constexpr auto memory_order_acquire = memory_order::acquire;
inline constexpr auto memory_order_release = memory_order::release;
inline constexpr auto memory_order_acq_rel = memory_order::acq_rel;
inline constexpr auto memory_order_seq_cst = memory_order::seq_cst;
template <class T> T kill_dependency(T y) noexcept;
Expand Down Expand Up @@ -577,14 +584,39 @@ void atomic_signal_fence(memory_order m) noexcept;

_LIBCPP_BEGIN_NAMESPACE_STD

typedef enum memory_order
{
memory_order_relaxed, memory_order_consume, memory_order_acquire,
memory_order_release, memory_order_acq_rel, memory_order_seq_cst
#if _LIBCPP_STD_VER > 17

enum class memory_order: unsigned {
relaxed, consume, acquire, release, acq_rel, seq_cst
};

inline constexpr auto memory_order_relaxed = memory_order::relaxed;
inline constexpr auto memory_order_consume = memory_order::consume;
inline constexpr auto memory_order_acquire = memory_order::acquire;
inline constexpr auto memory_order_release = memory_order::release;
inline constexpr auto memory_order_acq_rel = memory_order::acq_rel;
inline constexpr auto memory_order_seq_cst = memory_order::seq_cst;

static_assert((is_same<underlying_type<memory_order>::type,
unsigned>::value), "Underlying type differs from unsigned unexpectedly");

#else

typedef enum memory_order {
memory_order_relaxed, memory_order_consume, memory_order_acquire,
memory_order_release, memory_order_acq_rel, memory_order_seq_cst
} memory_order;

static_assert((is_same<underlying_type<memory_order>::type,
unsigned>::value), "Underlying type differs from unsigned unexpectedly");

#endif // _LIBCPP_STD_VER > 17

typedef underlying_type<memory_order>::type __memory_order_underlying_t; // unsigned


#if defined(_LIBCPP_HAS_GCC_ATOMIC_IMP) || \
defined(_LIBCPP_ATOMIC_ONLY_USE_BUILTINS)
defined(_LIBCPP_ATOMIC_ONLY_USE_BUILTINS)

// [atomics.types.generic]p1 guarantees _Tp is trivially copyable. Because
// the default operator= in an object is not volatile, a byte-by-byte copy
Expand Down Expand Up @@ -1423,65 +1455,65 @@ struct __atomic_base // false
_LIBCPP_INLINE_VISIBILITY
void store(_Tp __d, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
_LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
{__cxx_atomic_store(&__a_, __d, __m);}
{__cxx_atomic_store(&__a_, __d, static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
void store(_Tp __d, memory_order __m = memory_order_seq_cst) _NOEXCEPT
_LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
{__cxx_atomic_store(&__a_, __d, __m);}
{__cxx_atomic_store(&__a_, __d, static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
_Tp load(memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
_LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
{return __cxx_atomic_load(&__a_, __m);}
{return __cxx_atomic_load(&__a_, static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
_Tp load(memory_order __m = memory_order_seq_cst) const _NOEXCEPT
_LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
{return __cxx_atomic_load(&__a_, __m);}
{return __cxx_atomic_load(&__a_, static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
operator _Tp() const volatile _NOEXCEPT {return load();}
_LIBCPP_INLINE_VISIBILITY
operator _Tp() const _NOEXCEPT {return load();}
_LIBCPP_INLINE_VISIBILITY
_Tp exchange(_Tp __d, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
{return __cxx_atomic_exchange(&__a_, __d, __m);}
{return __cxx_atomic_exchange(&__a_, __d, static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
_Tp exchange(_Tp __d, memory_order __m = memory_order_seq_cst) _NOEXCEPT
{return __cxx_atomic_exchange(&__a_, __d, __m);}
{return __cxx_atomic_exchange(&__a_, __d, static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
bool compare_exchange_weak(_Tp& __e, _Tp __d,
memory_order __s, memory_order __f) volatile _NOEXCEPT
_LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
{return __cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __s, __f);}
{return __cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, static_cast<__memory_order_underlying_t>(__s), static_cast<__memory_order_underlying_t>(__f));}
_LIBCPP_INLINE_VISIBILITY
bool compare_exchange_weak(_Tp& __e, _Tp __d,
memory_order __s, memory_order __f) _NOEXCEPT
_LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
{return __cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __s, __f);}
{return __cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, static_cast<__memory_order_underlying_t>(__s), static_cast<__memory_order_underlying_t>(__f));}
_LIBCPP_INLINE_VISIBILITY
bool compare_exchange_strong(_Tp& __e, _Tp __d,
memory_order __s, memory_order __f) volatile _NOEXCEPT
_LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
{return __cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __s, __f);}
{return __cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, static_cast<__memory_order_underlying_t>(__s), static_cast<__memory_order_underlying_t>(__f));}
_LIBCPP_INLINE_VISIBILITY
bool compare_exchange_strong(_Tp& __e, _Tp __d,
memory_order __s, memory_order __f) _NOEXCEPT
_LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
{return __cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __s, __f);}
{return __cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, static_cast<__memory_order_underlying_t>(__s), static_cast<__memory_order_underlying_t>(__f));}
_LIBCPP_INLINE_VISIBILITY
bool compare_exchange_weak(_Tp& __e, _Tp __d,
memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
{return __cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __m, __m);}
{return __cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, static_cast<__memory_order_underlying_t>(__m), static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
bool compare_exchange_weak(_Tp& __e, _Tp __d,
memory_order __m = memory_order_seq_cst) _NOEXCEPT
{return __cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __m, __m);}
{return __cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, static_cast<__memory_order_underlying_t>(__m), static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
bool compare_exchange_strong(_Tp& __e, _Tp __d,
memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
{return __cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __m, __m);}
{return __cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, static_cast<__memory_order_underlying_t>(__m), static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
bool compare_exchange_strong(_Tp& __e, _Tp __d,
memory_order __m = memory_order_seq_cst) _NOEXCEPT
{return __cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __m, __m);}
{return __cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, static_cast<__memory_order_underlying_t>(__m), static_cast<__memory_order_underlying_t>(__m));}

_LIBCPP_INLINE_VISIBILITY
__atomic_base() _NOEXCEPT _LIBCPP_DEFAULT
Expand Down Expand Up @@ -1520,34 +1552,34 @@ struct __atomic_base<_Tp, true>

_LIBCPP_INLINE_VISIBILITY
_Tp fetch_add(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
{return __cxx_atomic_fetch_add(&this->__a_, __op, __m);}
{return __cxx_atomic_fetch_add(&this->__a_, __op, static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
_Tp fetch_add(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
{return __cxx_atomic_fetch_add(&this->__a_, __op, __m);}
{return __cxx_atomic_fetch_add(&this->__a_, __op, static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
_Tp fetch_sub(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
{return __cxx_atomic_fetch_sub(&this->__a_, __op, __m);}
{return __cxx_atomic_fetch_sub(&this->__a_, __op, static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
_Tp fetch_sub(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
{return __cxx_atomic_fetch_sub(&this->__a_, __op, __m);}
{return __cxx_atomic_fetch_sub(&this->__a_, __op, static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
_Tp fetch_and(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
{return __cxx_atomic_fetch_and(&this->__a_, __op, __m);}
{return __cxx_atomic_fetch_and(&this->__a_, __op, static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
_Tp fetch_and(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
{return __cxx_atomic_fetch_and(&this->__a_, __op, __m);}
{return __cxx_atomic_fetch_and(&this->__a_, __op, static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
_Tp fetch_or(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
{return __cxx_atomic_fetch_or(&this->__a_, __op, __m);}
{return __cxx_atomic_fetch_or(&this->__a_, __op, static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
_Tp fetch_or(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
{return __cxx_atomic_fetch_or(&this->__a_, __op, __m);}
{return __cxx_atomic_fetch_or(&this->__a_, __op, static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
_Tp fetch_xor(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
{return __cxx_atomic_fetch_xor(&this->__a_, __op, __m);}
{return __cxx_atomic_fetch_xor(&this->__a_, __op, static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
_Tp fetch_xor(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
{return __cxx_atomic_fetch_xor(&this->__a_, __op, __m);}
{return __cxx_atomic_fetch_xor(&this->__a_, __op, static_cast<__memory_order_underlying_t>(__m));}

_LIBCPP_INLINE_VISIBILITY
_Tp operator++(int) volatile _NOEXCEPT {return fetch_add(_Tp(1));}
Expand Down Expand Up @@ -1629,17 +1661,17 @@ struct atomic<_Tp*>
_LIBCPP_INLINE_VISIBILITY
_Tp* fetch_add(ptrdiff_t __op, memory_order __m = memory_order_seq_cst)
volatile _NOEXCEPT
{return __cxx_atomic_fetch_add(&this->__a_, __op, __m);}
{return __cxx_atomic_fetch_add(&this->__a_, __op, static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
_Tp* fetch_add(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
{return __cxx_atomic_fetch_add(&this->__a_, __op, __m);}
{return __cxx_atomic_fetch_add(&this->__a_, __op, static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
_Tp* fetch_sub(ptrdiff_t __op, memory_order __m = memory_order_seq_cst)
volatile _NOEXCEPT
{return __cxx_atomic_fetch_sub(&this->__a_, __op, __m);}
{return __cxx_atomic_fetch_sub(&this->__a_, __op, static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
_Tp* fetch_sub(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
{return __cxx_atomic_fetch_sub(&this->__a_, __op, __m);}
{return __cxx_atomic_fetch_sub(&this->__a_, __op, static_cast<__memory_order_underlying_t>(__m));}

_LIBCPP_INLINE_VISIBILITY
_Tp* operator++(int) volatile _NOEXCEPT {return fetch_add(1);}
Expand Down Expand Up @@ -2232,16 +2264,16 @@ typedef struct atomic_flag

_LIBCPP_INLINE_VISIBILITY
bool test_and_set(memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
{return __cxx_atomic_exchange(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(true), __m);}
{return __cxx_atomic_exchange(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(true), static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
bool test_and_set(memory_order __m = memory_order_seq_cst) _NOEXCEPT
{return __cxx_atomic_exchange(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(true), __m);}
{return __cxx_atomic_exchange(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(true), static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
void clear(memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
{__cxx_atomic_store(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(false), __m);}
{__cxx_atomic_store(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(false), static_cast<__memory_order_underlying_t>(__m));}
_LIBCPP_INLINE_VISIBILITY
void clear(memory_order __m = memory_order_seq_cst) _NOEXCEPT
{__cxx_atomic_store(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(false), __m);}
{__cxx_atomic_store(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(false), static_cast<__memory_order_underlying_t>(__m));}

_LIBCPP_INLINE_VISIBILITY
atomic_flag() _NOEXCEPT _LIBCPP_DEFAULT
Expand Down Expand Up @@ -2323,14 +2355,14 @@ inline _LIBCPP_INLINE_VISIBILITY
void
atomic_thread_fence(memory_order __m) _NOEXCEPT
{
__cxx_atomic_thread_fence(__m);
__cxx_atomic_thread_fence(static_cast<__memory_order_underlying_t>(__m));
}

inline _LIBCPP_INLINE_VISIBILITY
void
atomic_signal_fence(memory_order __m) _NOEXCEPT
{
__cxx_atomic_signal_fence(__m);
__cxx_atomic_signal_fence(static_cast<__memory_order_underlying_t>(__m));
}

// Atomics for standard typedef types
Expand Down
17 changes: 9 additions & 8 deletions libcxx/test/std/atomics/atomics.order/memory_order.pass.cpp
View file
Expand Up @@ -21,14 +21,15 @@

int main(int, char**)
{
assert(std::memory_order_relaxed == 0);
assert(std::memory_order_consume == 1);
assert(std::memory_order_acquire == 2);
assert(std::memory_order_release == 3);
assert(std::memory_order_acq_rel == 4);
assert(std::memory_order_seq_cst == 5);
assert(static_cast<int>(std::memory_order_relaxed) == 0);
assert(static_cast<int>(std::memory_order_consume) == 1);
assert(static_cast<int>(std::memory_order_acquire) == 2);
assert(static_cast<int>(std::memory_order_release) == 3);
assert(static_cast<int>(std::memory_order_acq_rel) == 4);
assert(static_cast<int>(std::memory_order_seq_cst) == 5);

std::memory_order o = std::memory_order_seq_cst;
assert(o == 5);
assert(static_cast<int>(o) == 5);

return 0;
return 0;
}
23 changes: 23 additions & 0 deletions libcxx/test/std/atomics/atomics.order/memory_order_new.pass.cpp
View file
@@ -0,0 +1,23 @@
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// UNSUPPORTED: libcpp-has-no-threads, c++98, c++03, c++11, c++14, c++17

#include <atomic>

int main(int, char**)
{
static_assert(std::memory_order_relaxed == std::memory_order::relaxed);
static_assert(std::memory_order_consume == std::memory_order::consume);
static_assert(std::memory_order_acquire == std::memory_order::acquire);
static_assert(std::memory_order_release == std::memory_order::release);
static_assert(std::memory_order_acq_rel == std::memory_order::acq_rel);
static_assert(std::memory_order_seq_cst == std::memory_order::seq_cst);

return 0;
}
2 changes: 1 addition & 1 deletion libcxx/www/cxx2a_status.html
View file
Expand Up @@ -61,7 +61,7 @@ <h3>Paper Status</h3>
<tr><td><a href="https://wg21.link/P0053R7">P0053R7</a></td><td>LWG</td><td>C++ Synchronized Buffered Ostream</td><td>Albuquerque</td><td></td><td></td></tr>
<tr><td><a href="https://wg21.link/P0202R3">P0202R3</a></td><td>LWG</td><td>Add constexpr modifiers to functions in &lt;algorithm&gt; and &lt;utility&gt; Headers</td><td>Albuquerque</td><td><I>In Progress</I></td><td>7.0</td></tr>
<tr><td><a href="https://wg21.link/P0415R1">P0415R1</a></td><td>LWG</td><td>Constexpr for <tt>std::complex</tt></td><td>Albuquerque</td><td><I>In Progress</I></td><td>7.0</td></tr>
<tr><td><a href="https://wg21.link/P0439R0">P0439R0</a></td><td>LWG</td><td>Make <tt>std::memory_order</tt> a scoped enumeration</td><td>Albuquerque</td><td></td><td></td></tr>
<tr><td><a href="https://wg21.link/P0439R0">P0439R0</a></td><td>LWG</td><td>Make <tt>std::memory_order</tt> a scoped enumeration</td><td>Albuquerque</td><td>Complete</td><td></td></tr>
<tr><td><a href="https://wg21.link/P0457R2">P0457R2</a></td><td>LWG</td><td>String Prefix and Suffix Checking</td><td>Albuquerque</td><td>Complete</td><td>6.0</td></tr>
<tr><td><a href="https://wg21.link/P0550R2">P0550R2</a></td><td>LWG</td><td>Transformation Trait <tt>remove_cvref</tt></td><td>Albuquerque</td><td>Complete</td><td>6.0</td></tr>
<tr><td><a href="https://wg21.link/P0600R1">P0600R1</a></td><td>LWG</td><td>nodiscard in the Library</td><td>Albuquerque</td><td><I>In Progress</I></td><td>7.0</td></tr>
Expand Down

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