1// -*- C++ -*-
2//===--------------------------- thread -----------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP_THREAD
11#define _LIBCPP_THREAD
12
13/*
14
15 thread synopsis
16
17#define __STDCPP_THREADS__ __cplusplus
18
19namespace std
20{
21
22class thread
23{
24public:
25 class id;
26 typedef pthread_t native_handle_type;
27
28 thread() noexcept;
29 template <class F, class ...Args> explicit thread(F&& f, Args&&... args);
30 ~thread();
31
32 thread(const thread&) = delete;
33 thread(thread&& t) noexcept;
34
35 thread& operator=(const thread&) = delete;
36 thread& operator=(thread&& t) noexcept;
37
38 void swap(thread& t) noexcept;
39
40 bool joinable() const noexcept;
41 void join();
42 void detach();
43 id get_id() const noexcept;
44 native_handle_type native_handle();
45
46 static unsigned hardware_concurrency() noexcept;
47};
48
49void swap(thread& x, thread& y) noexcept;
50
51class thread::id
52{
53public:
54 id() noexcept;
55};
56
57bool operator==(thread::id x, thread::id y) noexcept;
58bool operator!=(thread::id x, thread::id y) noexcept;
59bool operator< (thread::id x, thread::id y) noexcept;
60bool operator<=(thread::id x, thread::id y) noexcept;
61bool operator> (thread::id x, thread::id y) noexcept;
62bool operator>=(thread::id x, thread::id y) noexcept;
63
64template<class charT, class traits>
65basic_ostream<charT, traits>&
66operator<<(basic_ostream<charT, traits>& out, thread::id id);
67
68namespace this_thread
69{
70
71thread::id get_id() noexcept;
72
73void yield() noexcept;
74
75template <class Clock, class Duration>
76void sleep_until(const chrono::time_point<Clock, Duration>& abs_time);
77
78template <class Rep, class Period>
79void sleep_for(const chrono::duration<Rep, Period>& rel_time);
80
81} // this_thread
82
83} // std
84
85*/
86
87#include <__config>
88#include <iosfwd>
89#include <__functional_base>
90#include <type_traits>
91#include <cstddef>
92#include <functional>
93#include <memory>
94#include <system_error>
95#include <chrono>
96#include <__mutex_base>
97#ifndef _LIBCPP_CXX03_LANG
98#include <tuple>
99#endif
100#include <__threading_support>
101#include <__debug>
102
103#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
104#pragma GCC system_header
105#endif
106
107_LIBCPP_PUSH_MACROS
108#include <__undef_macros>
109
110#define __STDCPP_THREADS__ __cplusplus
111
112#ifdef _LIBCPP_HAS_NO_THREADS
113#error <thread> is not supported on this single threaded system
114#else // !_LIBCPP_HAS_NO_THREADS
115
116_LIBCPP_BEGIN_NAMESPACE_STD
117
118template <class _Tp> class __thread_specific_ptr;
119class _LIBCPP_TYPE_VIS __thread_struct;
120class _LIBCPP_HIDDEN __thread_struct_imp;
121class __assoc_sub_state;
122
123_LIBCPP_FUNC_VIS __thread_specific_ptr<__thread_struct>& __thread_local_data();
124
125class _LIBCPP_TYPE_VIS __thread_struct
126{
127 __thread_struct_imp* __p_;
128
129 __thread_struct(const __thread_struct&);
130 __thread_struct& operator=(const __thread_struct&);
131public:
132 __thread_struct();
133 ~__thread_struct();
134
135 void notify_all_at_thread_exit(condition_variable*, mutex*);
136 void __make_ready_at_thread_exit(__assoc_sub_state*);
137};
138
139template <class _Tp>
140class __thread_specific_ptr
141{
142 __libcpp_tls_key __key_;
143
144 // Only __thread_local_data() may construct a __thread_specific_ptr
145 // and only with _Tp == __thread_struct.
146 static_assert((is_same<_Tp, __thread_struct>::value), "");
147 __thread_specific_ptr();
148 friend _LIBCPP_FUNC_VIS __thread_specific_ptr<__thread_struct>& __thread_local_data();
149
150 __thread_specific_ptr(const __thread_specific_ptr&);
151 __thread_specific_ptr& operator=(const __thread_specific_ptr&);
152
153 _LIBCPP_HIDDEN static void _LIBCPP_TLS_DESTRUCTOR_CC __at_thread_exit(void*);
154
155public:
156 typedef _Tp* pointer;
157
158 ~__thread_specific_ptr();
159
160 _LIBCPP_INLINE_VISIBILITY
161 pointer get() const {return static_cast<_Tp*>(__libcpp_tls_get(__key_));}
162 _LIBCPP_INLINE_VISIBILITY
163 pointer operator*() const {return *get();}
164 _LIBCPP_INLINE_VISIBILITY
165 pointer operator->() const {return get();}
166 void set_pointer(pointer __p);
167};
168
169template <class _Tp>
170void _LIBCPP_TLS_DESTRUCTOR_CC
171__thread_specific_ptr<_Tp>::__at_thread_exit(void* __p)
172{
173 delete static_cast<pointer>(__p);
174}
175
176template <class _Tp>
177__thread_specific_ptr<_Tp>::__thread_specific_ptr()
178{
179 int __ec =
180 __libcpp_tls_create(&__key_, &__thread_specific_ptr::__at_thread_exit);
181 if (__ec)
182 __throw_system_error(__ec, "__thread_specific_ptr construction failed");
183}
184
185template <class _Tp>
186__thread_specific_ptr<_Tp>::~__thread_specific_ptr()
187{
188 // __thread_specific_ptr is only created with a static storage duration
189 // so this destructor is only invoked during program termination. Invoking
190 // pthread_key_delete(__key_) may prevent other threads from deleting their
191 // thread local data. For this reason we leak the key.
192}
193
194template <class _Tp>
195void
196__thread_specific_ptr<_Tp>::set_pointer(pointer __p)
197{
198 _LIBCPP_ASSERT(get() == nullptr,
199 "Attempting to overwrite thread local data");
200 __libcpp_tls_set(__key_, __p);
201}
202
203class _LIBCPP_TYPE_VIS thread;
204class _LIBCPP_TYPE_VIS __thread_id;
205
206namespace this_thread
207{
208
209_LIBCPP_INLINE_VISIBILITY __thread_id get_id() _NOEXCEPT;
210
211} // this_thread
212
213template<> struct hash<__thread_id>;
214
215class _LIBCPP_TEMPLATE_VIS __thread_id
216{
217 // FIXME: pthread_t is a pointer on Darwin but a long on Linux.
218 // NULL is the no-thread value on Darwin. Someone needs to check
219 // on other platforms. We assume 0 works everywhere for now.
220 __libcpp_thread_id __id_;
221
222public:
223 _LIBCPP_INLINE_VISIBILITY
224 __thread_id() _NOEXCEPT : __id_(0) {}
225
226 friend _LIBCPP_INLINE_VISIBILITY
227 bool operator==(__thread_id __x, __thread_id __y) _NOEXCEPT
228 {return __libcpp_thread_id_equal(__x.__id_, __y.__id_);}
229 friend _LIBCPP_INLINE_VISIBILITY
230 bool operator!=(__thread_id __x, __thread_id __y) _NOEXCEPT
231 {return !(__x == __y);}
232 friend _LIBCPP_INLINE_VISIBILITY
233 bool operator< (__thread_id __x, __thread_id __y) _NOEXCEPT
234 {return __libcpp_thread_id_less(__x.__id_, __y.__id_);}
235 friend _LIBCPP_INLINE_VISIBILITY
236 bool operator<=(__thread_id __x, __thread_id __y) _NOEXCEPT
237 {return !(__y < __x);}
238 friend _LIBCPP_INLINE_VISIBILITY
239 bool operator> (__thread_id __x, __thread_id __y) _NOEXCEPT
240 {return __y < __x ;}
241 friend _LIBCPP_INLINE_VISIBILITY
242 bool operator>=(__thread_id __x, __thread_id __y) _NOEXCEPT
243 {return !(__x < __y);}
244
245 template<class _CharT, class _Traits>
246 friend
247 _LIBCPP_INLINE_VISIBILITY
248 basic_ostream<_CharT, _Traits>&
249 operator<<(basic_ostream<_CharT, _Traits>& __os, __thread_id __id)
250 {return __os << __id.__id_;}
251
252private:
253 _LIBCPP_INLINE_VISIBILITY
254 __thread_id(__libcpp_thread_id __id) : __id_(__id) {}
255
256 friend __thread_id this_thread::get_id() _NOEXCEPT;
257 friend class _LIBCPP_TYPE_VIS thread;
258 friend struct _LIBCPP_TEMPLATE_VIS hash<__thread_id>;
259};
260
261template<>
262struct _LIBCPP_TEMPLATE_VIS hash<__thread_id>
263 : public unary_function<__thread_id, size_t>
264{
265 _LIBCPP_INLINE_VISIBILITY
266 size_t operator()(__thread_id __v) const _NOEXCEPT
267 {
268 return hash<__libcpp_thread_id>()(__v.__id_);
269 }
270};
271
272namespace this_thread
273{
274
275inline _LIBCPP_INLINE_VISIBILITY
276__thread_id
277get_id() _NOEXCEPT
278{
279 return __libcpp_thread_get_current_id();
280}
281
282} // this_thread
283
284class _LIBCPP_TYPE_VIS thread
285{
286 __libcpp_thread_t __t_;
287
288 thread(const thread&);
289 thread& operator=(const thread&);
290public:
291 typedef __thread_id id;
292 typedef __libcpp_thread_t native_handle_type;
293
294 _LIBCPP_INLINE_VISIBILITY
295 thread() _NOEXCEPT : __t_(_LIBCPP_NULL_THREAD) {}
296#ifndef _LIBCPP_CXX03_LANG
297 template <class _Fp, class ..._Args,
298 class = typename enable_if
299 <
300 !is_same<typename __uncvref<_Fp>::type, thread>::value
301 >::type
302 >
303 _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
304 explicit thread(_Fp&& __f, _Args&&... __args);
305#else // _LIBCPP_CXX03_LANG
306 template <class _Fp>
307 _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
308 explicit thread(_Fp __f);
309#endif
310 ~thread();
311
312#ifndef _LIBCPP_CXX03_LANG
313 _LIBCPP_INLINE_VISIBILITY
314 thread(thread&& __t) _NOEXCEPT : __t_(__t.__t_) {__t.__t_ = _LIBCPP_NULL_THREAD;}
315 _LIBCPP_INLINE_VISIBILITY
316 thread& operator=(thread&& __t) _NOEXCEPT;
317#endif // _LIBCPP_CXX03_LANG
318
319 _LIBCPP_INLINE_VISIBILITY
320 void swap(thread& __t) _NOEXCEPT {_VSTD::swap(__t_, __t.__t_);}
321
322 _LIBCPP_INLINE_VISIBILITY
323 bool joinable() const _NOEXCEPT {return !__libcpp_thread_isnull(&__t_);}
324 void join();
325 void detach();
326 _LIBCPP_INLINE_VISIBILITY
327 id get_id() const _NOEXCEPT {return __libcpp_thread_get_id(&__t_);}
328 _LIBCPP_INLINE_VISIBILITY
329 native_handle_type native_handle() _NOEXCEPT {return __t_;}
330
331 static unsigned hardware_concurrency() _NOEXCEPT;
332};
333
334#ifndef _LIBCPP_CXX03_LANG
335
336template <class _TSp, class _Fp, class ..._Args, size_t ..._Indices>
337inline _LIBCPP_INLINE_VISIBILITY
338void
339__thread_execute(tuple<_TSp, _Fp, _Args...>& __t, __tuple_indices<_Indices...>)
340{
341 __invoke(_VSTD::move(_VSTD::get<1>(__t)), _VSTD::move(_VSTD::get<_Indices>(__t))...);
342}
343
344template <class _Fp>
345void* __thread_proxy(void* __vp)
346{
347 // _Fp = std::tuple< unique_ptr<__thread_struct>, Functor, Args...>
348 std::unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
349 __thread_local_data().set_pointer(_VSTD::get<0>(*__p).release());
350 typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 2>::type _Index;
351 __thread_execute(*__p, _Index());
352 return nullptr;
353}
354
355template <class _Fp, class ..._Args,
356 class
357 >
358thread::thread(_Fp&& __f, _Args&&... __args)
359{
360 typedef unique_ptr<__thread_struct> _TSPtr;
361 _TSPtr __tsp(new __thread_struct);
362 typedef tuple<_TSPtr, typename decay<_Fp>::type, typename decay<_Args>::type...> _Gp;
363 _VSTD::unique_ptr<_Gp> __p(
364 new _Gp(std::move(__tsp),
365 __decay_copy(_VSTD::forward<_Fp>(__f)),
366 __decay_copy(_VSTD::forward<_Args>(__args))...));
367 int __ec = __libcpp_thread_create(&__t_, &__thread_proxy<_Gp>, __p.get());
368 if (__ec == 0)
369 __p.release();
370 else
371 __throw_system_error(__ec, "thread constructor failed");
372}
373
374inline
375thread&
376thread::operator=(thread&& __t) _NOEXCEPT
377{
378 if (!__libcpp_thread_isnull(&__t_))
379 terminate();
380 __t_ = __t.__t_;
381 __t.__t_ = _LIBCPP_NULL_THREAD;
382 return *this;
383}
384
385#else // _LIBCPP_CXX03_LANG
386
387template <class _Fp>
388struct __thread_invoke_pair {
389 // This type is used to pass memory for thread local storage and a functor
390 // to a newly created thread because std::pair doesn't work with
391 // std::unique_ptr in C++03.
392 __thread_invoke_pair(_Fp& __f) : __tsp_(new __thread_struct), __fn_(__f) {}
393 unique_ptr<__thread_struct> __tsp_;
394 _Fp __fn_;
395};
396
397template <class _Fp>
398void* __thread_proxy_cxx03(void* __vp)
399{
400 std::unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
401 __thread_local_data().set_pointer(__p->__tsp_.release());
402 (__p->__fn_)();
403 return nullptr;
404}
405
406template <class _Fp>
407thread::thread(_Fp __f)
408{
409
410 typedef __thread_invoke_pair<_Fp> _InvokePair;
411 typedef std::unique_ptr<_InvokePair> _PairPtr;
412 _PairPtr __pp(new _InvokePair(__f));
413 int __ec = __libcpp_thread_create(&__t_, &__thread_proxy_cxx03<_InvokePair>, __pp.get());
414 if (__ec == 0)
415 __pp.release();
416 else
417 __throw_system_error(__ec, "thread constructor failed");
418}
419
420#endif // _LIBCPP_CXX03_LANG
421
422inline _LIBCPP_INLINE_VISIBILITY
423void swap(thread& __x, thread& __y) _NOEXCEPT {__x.swap(__y);}
424
425namespace this_thread
426{
427
428_LIBCPP_FUNC_VIS void sleep_for(const chrono::nanoseconds& __ns);
429
430template <class _Rep, class _Period>
431void
432sleep_for(const chrono::duration<_Rep, _Period>& __d)
433{
434 using namespace chrono;
435 if (__d > duration<_Rep, _Period>::zero())
436 {
437#if defined(_LIBCPP_COMPILER_GCC) && (__powerpc__ || __POWERPC__)
438 // GCC's long double const folding is incomplete for IBM128 long doubles.
439 _LIBCPP_CONSTEXPR duration<long double> _Max = nanoseconds::max();
440#else
441 _LIBCPP_CONSTEXPR duration<long double> _Max = duration<long double>(ULLONG_MAX/1000000000ULL) ;
442#endif
443 nanoseconds __ns;
444 if (__d < _Max)
445 {
446 __ns = duration_cast<nanoseconds>(__d);
447 if (__ns < __d)
448 ++__ns;
449 }
450 else
451 __ns = nanoseconds::max();
452 sleep_for(__ns);
453 }
454}
455
456template <class _Clock, class _Duration>
457void
458sleep_until(const chrono::time_point<_Clock, _Duration>& __t)
459{
460 using namespace chrono;
461 mutex __mut;
462 condition_variable __cv;
463 unique_lock<mutex> __lk(__mut);
464 while (_Clock::now() < __t)
465 __cv.wait_until(__lk, __t);
466}
467
468template <class _Duration>
469inline _LIBCPP_INLINE_VISIBILITY
470void
471sleep_until(const chrono::time_point<chrono::steady_clock, _Duration>& __t)
472{
473 using namespace chrono;
474 sleep_for(__t - steady_clock::now());
475}
476
477inline _LIBCPP_INLINE_VISIBILITY
478void yield() _NOEXCEPT {__libcpp_thread_yield();}
479
480} // this_thread
481
482_LIBCPP_END_NAMESPACE_STD
483
484#endif // !_LIBCPP_HAS_NO_THREADS
485
486_LIBCPP_POP_MACROS
487
488#endif // _LIBCPP_THREAD
489