diff options
Diffstat (limited to 'libstdc++-v3/src/c++17/memory_resource.cc')
| -rw-r--r-- | libstdc++-v3/src/c++17/memory_resource.cc | 41 |
1 files changed, 40 insertions, 1 deletions
diff --git a/libstdc++-v3/src/c++17/memory_resource.cc b/libstdc++-v3/src/c++17/memory_resource.cc index c3ae2b69f71..bd8f32d931e 100644 --- a/libstdc++-v3/src/c++17/memory_resource.cc +++ b/libstdc++-v3/src/c++17/memory_resource.cc @@ -25,6 +25,10 @@ #include <memory_resource> #include <atomic> #include <new> +#if ATOMIC_POINTER_LOCK_FREE != 2 +# include <bits/std_mutex.h> // std::mutex, std::lock_guard +# include <bits/move.h> // std::exchange +#endif namespace std _GLIBCXX_VISIBILITY(default) { @@ -81,7 +85,42 @@ namespace pmr constant_init<newdel_res_t> newdel_res{}; constant_init<null_res_t> null_res{}; - constant_init<atomic<memory_resource*>> default_res{&newdel_res.obj}; +#if ATOMIC_POINTER_LOCK_FREE == 2 + using atomic_mem_res = atomic<memory_resource*>; +# define _GLIBCXX_ATOMIC_MEM_RES_CAN_BE_CONSTANT_INITIALIZED +#else + // Can't use pointer-width atomics, define a type using a mutex instead: + struct atomic_mem_res + { +# ifdef __GTHREAD_MUTEX_INIT +# define _GLIBCXX_ATOMIC_MEM_RES_CAN_BE_CONSTANT_INITIALIZED + // std::mutex has constexpr constructor + constexpr +# endif + atomic_mem_res(memory_resource* r) : val(r) { } + + mutex mx; + memory_resource* val; + + memory_resource* load() + { + lock_guard<mutex> lock(mx); + return val; + } + + memory_resource* exchange(memory_resource* r) + { + lock_guard<mutex> lock(mx); + return std::exchange(val, r); + } + }; +#endif // ATOMIC_POINTER_LOCK_FREE == 2 + +#ifdef _GLIBCXX_ATOMIC_MEM_RES_CAN_BE_CONSTANT_INITIALIZED + constant_init<atomic_mem_res> default_res{&newdel_res.obj}; +#else +# include "default_resource.h" +#endif } // namespace memory_resource* |