1 //===------------------------ memory.cpp ----------------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #define _LIBCPP_BUILDING_MEMORY
15 _LIBCPP_BEGIN_NAMESPACE_STD
22 increment(T& t) _NOEXCEPT
24 return __sync_add_and_fetch(&t, 1);
29 decrement(T& t) _NOEXCEPT
31 return __sync_add_and_fetch(&t, -1);
36 const allocator_arg_t allocator_arg = allocator_arg_t();
38 bad_weak_ptr::~bad_weak_ptr() _NOEXCEPT {}
41 bad_weak_ptr::what() const _NOEXCEPT
43 return "bad_weak_ptr";
46 __shared_count::~__shared_count()
51 __shared_count::__add_shared() _NOEXCEPT
53 increment(__shared_owners_);
57 __shared_count::__release_shared() _NOEXCEPT
59 if (decrement(__shared_owners_) == -1)
67 __shared_weak_count::~__shared_weak_count()
72 __shared_weak_count::__add_shared() _NOEXCEPT
74 __shared_count::__add_shared();
78 __shared_weak_count::__add_weak() _NOEXCEPT
80 increment(__shared_weak_owners_);
84 __shared_weak_count::__release_shared() _NOEXCEPT
86 if (__shared_count::__release_shared())
91 __shared_weak_count::__release_weak() _NOEXCEPT
93 if (decrement(__shared_weak_owners_) == -1)
94 __on_zero_shared_weak();
98 __shared_weak_count::lock() _NOEXCEPT
100 long object_owners = __shared_owners_;
101 while (object_owners != -1)
103 if (__sync_bool_compare_and_swap(&__shared_owners_,
107 object_owners = __shared_owners_;
112 #ifndef _LIBCPP_NO_RTTI
115 __shared_weak_count::__get_deleter(const type_info&) const _NOEXCEPT
120 #endif // _LIBCPP_NO_RTTI
122 #if __has_feature(cxx_atomic)
124 static const std::size_t __sp_mut_count = 16;
125 static mutex mut_back[__sp_mut_count];
127 _LIBCPP_CONSTEXPR __sp_mut::__sp_mut(void* p) _NOEXCEPT
133 __sp_mut::lock() _NOEXCEPT
135 mutex& m = *static_cast<mutex*>(_);
137 while (!m.try_lock())
144 this_thread::yield();
149 __sp_mut::unlock() _NOEXCEPT
151 static_cast<mutex*>(_)->unlock();
155 __get_sp_mut(const void* p)
157 static __sp_mut muts[__sp_mut_count]
159 &mut_back[ 0], &mut_back[ 1], &mut_back[ 2], &mut_back[ 3],
160 &mut_back[ 4], &mut_back[ 5], &mut_back[ 6], &mut_back[ 7],
161 &mut_back[ 8], &mut_back[ 9], &mut_back[10], &mut_back[11],
162 &mut_back[12], &mut_back[13], &mut_back[14], &mut_back[15]
164 return muts[hash<const void*>()(p) & (__sp_mut_count-1)];
167 #endif // __has_feature(cxx_atomic)
170 declare_reachable(void*)
175 declare_no_pointers(char*, size_t)
180 undeclare_no_pointers(char*, size_t)
185 get_pointer_safety() _NOEXCEPT
187 return pointer_safety::relaxed;
191 __undeclare_reachable(void* p)
197 align(size_t alignment, size_t size, void*& ptr, size_t& space)
202 char* p1 = static_cast<char*>(ptr);
203 char* p2 = (char*)((size_t)(p1 + (alignment - 1)) & -alignment);
204 size_t d = static_cast<size_t>(p2 - p1);
205 if (d <= space - size)
215 _LIBCPP_END_NAMESPACE_STD