jfb updated this revision to Diff 51607.
jfb added a comment.
Herald added a subscriber: jfb.
- Check feature test macro exists
http://reviews.llvm.org/D17951
Files:
include/atomic
test/std/atomics/atomics.lockfree/isalwayslockfree.pass.cpp
Index: test/std/atomics/atomics.lockfree/isalwayslockfree.pass.cpp
===================================================================
--- /dev/null
+++ test/std/atomics/atomics.lockfree/isalwayslockfree.pass.cpp
@@ -0,0 +1,101 @@
+//===----------------------------------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// UNSUPPORTED: libcpp-has-no-threads, c++98, c++03, c++11, c++14
+
+// <atomic>
+
+// static constexpr bool is_always_lock_free;
+
+#include <atomic>
+#include <cassert>
+
+#if !defined(__cpp_lib_atomic_is_always_lock_free)
+# error Feature test macro missing.
+#endif
+
+template <typename T> void checkAlwaysLockFree() {
+ if (std::atomic<T>::is_always_lock_free)
+ assert(std::atomic<T>().is_lock_free());
+}
+
+int main()
+{
+// structs and unions can't be defined in the template invocation.
+// Work around this with a typedef.
+#define CHECK_ALWAYS_LOCK_FREE(T) \
+ do { \
+ typedef T type; \
+ checkAlwaysLockFree<type>(); \
+ } while (0)
+
+ CHECK_ALWAYS_LOCK_FREE(bool);
+ CHECK_ALWAYS_LOCK_FREE(char);
+ CHECK_ALWAYS_LOCK_FREE(signed char);
+ CHECK_ALWAYS_LOCK_FREE(unsigned char);
+ CHECK_ALWAYS_LOCK_FREE(char16_t);
+ CHECK_ALWAYS_LOCK_FREE(char32_t);
+ CHECK_ALWAYS_LOCK_FREE(wchar_t);
+ CHECK_ALWAYS_LOCK_FREE(short);
+ CHECK_ALWAYS_LOCK_FREE(unsigned short);
+ CHECK_ALWAYS_LOCK_FREE(int);
+ CHECK_ALWAYS_LOCK_FREE(unsigned int);
+ CHECK_ALWAYS_LOCK_FREE(long);
+ CHECK_ALWAYS_LOCK_FREE(unsigned long);
+ CHECK_ALWAYS_LOCK_FREE(long long);
+ CHECK_ALWAYS_LOCK_FREE(unsigned long long);
+ CHECK_ALWAYS_LOCK_FREE(std::nullptr_t);
+ CHECK_ALWAYS_LOCK_FREE(void*);
+ CHECK_ALWAYS_LOCK_FREE(float);
+ CHECK_ALWAYS_LOCK_FREE(double);
+ CHECK_ALWAYS_LOCK_FREE(long double);
+ CHECK_ALWAYS_LOCK_FREE(int __attribute__((vector_size(1 * sizeof(int)))));
+ CHECK_ALWAYS_LOCK_FREE(int __attribute__((vector_size(2 * sizeof(int)))));
+ CHECK_ALWAYS_LOCK_FREE(int __attribute__((vector_size(4 * sizeof(int)))));
+ CHECK_ALWAYS_LOCK_FREE(int __attribute__((vector_size(16 * sizeof(int)))));
+ CHECK_ALWAYS_LOCK_FREE(int __attribute__((vector_size(32 * sizeof(int)))));
+ CHECK_ALWAYS_LOCK_FREE(float __attribute__((vector_size(1 * sizeof(float)))));
+ CHECK_ALWAYS_LOCK_FREE(float __attribute__((vector_size(2 * sizeof(float)))));
+ CHECK_ALWAYS_LOCK_FREE(float __attribute__((vector_size(4 * sizeof(float)))));
+ CHECK_ALWAYS_LOCK_FREE(float __attribute__((vector_size(16 * sizeof(float)))));
+ CHECK_ALWAYS_LOCK_FREE(float __attribute__((vector_size(32 * sizeof(float)))));
+ CHECK_ALWAYS_LOCK_FREE(double __attribute__((vector_size(1 * sizeof(double)))));
+ CHECK_ALWAYS_LOCK_FREE(double __attribute__((vector_size(2 * sizeof(double)))));
+ CHECK_ALWAYS_LOCK_FREE(double __attribute__((vector_size(4 * sizeof(double)))));
+ CHECK_ALWAYS_LOCK_FREE(double __attribute__((vector_size(16 * sizeof(double)))));
+ CHECK_ALWAYS_LOCK_FREE(double __attribute__((vector_size(32 * sizeof(double)))));
+ CHECK_ALWAYS_LOCK_FREE(struct{});
+ CHECK_ALWAYS_LOCK_FREE(struct{ int i; });
+ CHECK_ALWAYS_LOCK_FREE(struct{ int i[2]; });
+ CHECK_ALWAYS_LOCK_FREE(struct{ long long int i[2]; });
+ CHECK_ALWAYS_LOCK_FREE(struct{ long long int i[4]; });
+ CHECK_ALWAYS_LOCK_FREE(struct{ long long int i[8]; });
+ CHECK_ALWAYS_LOCK_FREE(struct{ long long int i[16]; });
+ CHECK_ALWAYS_LOCK_FREE(struct{ char c; /* padding */ long long int i; });
+ CHECK_ALWAYS_LOCK_FREE(union{ int i; float f; });
+
+ // C macro and static constexpr must be consistent.
+ static_assert(std::atomic<bool>::is_always_lock_free == (2 == ATOMIC_BOOL_LOCK_FREE));
+ static_assert(std::atomic<char>::is_always_lock_free == (2 == ATOMIC_CHAR_LOCK_FREE));
+ static_assert(std::atomic<signed char>::is_always_lock_free == (2 == ATOMIC_CHAR_LOCK_FREE));
+ static_assert(std::atomic<unsigned char>::is_always_lock_free == (2 == ATOMIC_CHAR_LOCK_FREE));
+ static_assert(std::atomic<char16_t>::is_always_lock_free == (2 == ATOMIC_CHAR16_T_LOCK_FREE));
+ static_assert(std::atomic<char32_t>::is_always_lock_free == (2 == ATOMIC_CHAR32_T_LOCK_FREE));
+ static_assert(std::atomic<wchar_t>::is_always_lock_free == (2 == ATOMIC_WCHAR_T_LOCK_FREE));
+ static_assert(std::atomic<short>::is_always_lock_free == (2 == ATOMIC_SHORT_LOCK_FREE));
+ static_assert(std::atomic<unsigned short>::is_always_lock_free == (2 == ATOMIC_SHORT_LOCK_FREE));
+ static_assert(std::atomic<int>::is_always_lock_free == (2 == ATOMIC_INT_LOCK_FREE));
+ static_assert(std::atomic<unsigned int>::is_always_lock_free == (2 == ATOMIC_INT_LOCK_FREE));
+ static_assert(std::atomic<long>::is_always_lock_free == (2 == ATOMIC_LONG_LOCK_FREE));
+ static_assert(std::atomic<unsigned long>::is_always_lock_free == (2 == ATOMIC_LONG_LOCK_FREE));
+ static_assert(std::atomic<long long>::is_always_lock_free == (2 == ATOMIC_LLONG_LOCK_FREE));
+ static_assert(std::atomic<unsigned long long>::is_always_lock_free == (2 == ATOMIC_LLONG_LOCK_FREE));
+ static_assert(std::atomic<void*>::is_always_lock_free == (2 == ATOMIC_POINTER_LOCK_FREE));
+ static_assert(std::atomic<std::nullptr_t>::is_always_lock_free == (2 == ATOMIC_POINTER_LOCK_FREE));
+}
Index: include/atomic
===================================================================
--- include/atomic
+++ include/atomic
@@ -17,6 +17,10 @@
namespace std
{
+// feature test macro
+
+#define __cpp_lib_atomic_is_always_lock_free // as specified by SG10
+
// order and consistency
typedef enum memory_order
@@ -89,6 +93,7 @@
template <class T>
struct atomic
{
+ static constexpr bool is_always_lock_free;
bool is_lock_free() const volatile noexcept;
bool is_lock_free() const noexcept;
void store(T desr, memory_order m = memory_order_seq_cst) volatile noexcept;
@@ -127,6 +132,7 @@
template <>
struct atomic<integral>
{
+ static constexpr bool is_always_lock_free;
bool is_lock_free() const volatile noexcept;
bool is_lock_free() const noexcept;
void store(integral desr, memory_order m = memory_order_seq_cst) volatile noexcept;
@@ -202,6 +208,7 @@
template <class T>
struct atomic<T*>
{
+ static constexpr bool is_always_lock_free;
bool is_lock_free() const volatile noexcept;
bool is_lock_free() const noexcept;
void store(T* desr, memory_order m = memory_order_seq_cst) volatile noexcept;
@@ -540,6 +547,11 @@
#error <atomic> is not implemented
#endif
+#if _LIBCPP_STD_VER > 14
+// FIXME: use the right feature test macro value as chose by SG10.
+# define __cpp_lib_atomic_is_always_lock_free 201603L
+#endif
+
_LIBCPP_BEGIN_NAMESPACE_STD
typedef enum memory_order
@@ -825,13 +837,28 @@
return __y;
}
+#define ATOMIC_BOOL_LOCK_FREE __GCC_ATOMIC_BOOL_LOCK_FREE
+#define ATOMIC_CHAR_LOCK_FREE __GCC_ATOMIC_CHAR_LOCK_FREE
+#define ATOMIC_CHAR16_T_LOCK_FREE __GCC_ATOMIC_CHAR16_T_LOCK_FREE
+#define ATOMIC_CHAR32_T_LOCK_FREE __GCC_ATOMIC_CHAR32_T_LOCK_FREE
+#define ATOMIC_WCHAR_T_LOCK_FREE __GCC_ATOMIC_WCHAR_T_LOCK_FREE
+#define ATOMIC_SHORT_LOCK_FREE __GCC_ATOMIC_SHORT_LOCK_FREE
+#define ATOMIC_INT_LOCK_FREE __GCC_ATOMIC_INT_LOCK_FREE
+#define ATOMIC_LONG_LOCK_FREE __GCC_ATOMIC_LONG_LOCK_FREE
+#define ATOMIC_LLONG_LOCK_FREE __GCC_ATOMIC_LLONG_LOCK_FREE
+#define ATOMIC_POINTER_LOCK_FREE __GCC_ATOMIC_POINTER_LOCK_FREE
+
// general atomic<T>
template <class _Tp, bool = is_integral<_Tp>::value && !is_same<_Tp, bool>::value>
struct __atomic_base // false
{
mutable _Atomic(_Tp) __a_;
+#if defined(__cpp_lib_atomic_is_always_lock_free)
+ static _LIBCPP_CONSTEXPR bool is_always_lock_free = __atomic_always_lock_free(sizeof(__a_), 0);
+#endif
+
_LIBCPP_INLINE_VISIBILITY
bool is_lock_free() const volatile _NOEXCEPT
{
@@ -920,6 +947,11 @@
#endif // _LIBCPP_HAS_NO_DELETED_FUNCTIONS
};
+#if defined(__cpp_lib_atomic_is_always_lock_free)
+template <class _Tp, bool __b>
+_LIBCPP_CONSTEXPR bool __atomic_base<_Tp, __b>::is_always_lock_free;
+#endif
+
// atomic<Integral>
template <class _Tp>
@@ -1789,17 +1821,6 @@
#define ATOMIC_FLAG_INIT {false}
#define ATOMIC_VAR_INIT(__v) {__v}
-#define ATOMIC_BOOL_LOCK_FREE __GCC_ATOMIC_BOOL_LOCK_FREE
-#define ATOMIC_CHAR_LOCK_FREE __GCC_ATOMIC_CHAR_LOCK_FREE
-#define ATOMIC_CHAR16_T_LOCK_FREE __GCC_ATOMIC_CHAR16_T_LOCK_FREE
-#define ATOMIC_CHAR32_T_LOCK_FREE __GCC_ATOMIC_CHAR32_T_LOCK_FREE
-#define ATOMIC_WCHAR_T_LOCK_FREE __GCC_ATOMIC_WCHAR_T_LOCK_FREE
-#define ATOMIC_SHORT_LOCK_FREE __GCC_ATOMIC_SHORT_LOCK_FREE
-#define ATOMIC_INT_LOCK_FREE __GCC_ATOMIC_INT_LOCK_FREE
-#define ATOMIC_LONG_LOCK_FREE __GCC_ATOMIC_LONG_LOCK_FREE
-#define ATOMIC_LLONG_LOCK_FREE __GCC_ATOMIC_LLONG_LOCK_FREE
-#define ATOMIC_POINTER_LOCK_FREE __GCC_ATOMIC_POINTER_LOCK_FREE
-
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP_ATOMIC
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