xref: /freebsd/contrib/llvm-project/libcxx/include/thread (revision 4b50c451720d8b427757a6da1dd2bb4c52cd9e35) 
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
203template<>
204struct _LIBCPP_TEMPLATE_VIS hash<__thread_id>
205    : public unary_function<__thread_id, size_t>
206{
207    _LIBCPP_INLINE_VISIBILITY
208    size_t operator()(__thread_id __v) const _NOEXCEPT
209    {
210        return hash<__libcpp_thread_id>()(__v.__id_);
211    }
212};
213
214template<class _CharT, class _Traits>
215_LIBCPP_INLINE_VISIBILITY
216basic_ostream<_CharT, _Traits>&
217operator<<(basic_ostream<_CharT, _Traits>& __os, __thread_id __id)
218{return __os << __id.__id_;}
219
220class _LIBCPP_TYPE_VIS thread
221{
222    __libcpp_thread_t __t_;
223
224    thread(const thread&);
225    thread& operator=(const thread&);
226public:
227    typedef __thread_id id;
228    typedef __libcpp_thread_t native_handle_type;
229
230    _LIBCPP_INLINE_VISIBILITY
231    thread() _NOEXCEPT : __t_(_LIBCPP_NULL_THREAD) {}
232#ifndef _LIBCPP_CXX03_LANG
233    template <class _Fp, class ..._Args,
234              class = typename enable_if
235              <
236                   !is_same<typename __uncvref<_Fp>::type, thread>::value
237              >::type
238             >
239        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
240        explicit thread(_Fp&& __f, _Args&&... __args);
241#else  // _LIBCPP_CXX03_LANG
242    template <class _Fp>
243    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
244    explicit thread(_Fp __f);
245#endif
246    ~thread();
247
248#ifndef _LIBCPP_CXX03_LANG
249    _LIBCPP_INLINE_VISIBILITY
250    thread(thread&& __t) _NOEXCEPT : __t_(__t.__t_) {__t.__t_ = _LIBCPP_NULL_THREAD;}
251    _LIBCPP_INLINE_VISIBILITY
252    thread& operator=(thread&& __t) _NOEXCEPT;
253#endif  // _LIBCPP_CXX03_LANG
254
255    _LIBCPP_INLINE_VISIBILITY
256    void swap(thread& __t) _NOEXCEPT {_VSTD::swap(__t_, __t.__t_);}
257
258    _LIBCPP_INLINE_VISIBILITY
259    bool joinable() const _NOEXCEPT {return !__libcpp_thread_isnull(&__t_);}
260    void join();
261    void detach();
262    _LIBCPP_INLINE_VISIBILITY
263    id get_id() const _NOEXCEPT {return __libcpp_thread_get_id(&__t_);}
264    _LIBCPP_INLINE_VISIBILITY
265    native_handle_type native_handle() _NOEXCEPT {return __t_;}
266
267    static unsigned hardware_concurrency() _NOEXCEPT;
268};
269
270#ifndef _LIBCPP_CXX03_LANG
271
272template <class _TSp, class _Fp, class ..._Args, size_t ..._Indices>
273inline _LIBCPP_INLINE_VISIBILITY
274void
275__thread_execute(tuple<_TSp, _Fp, _Args...>& __t, __tuple_indices<_Indices...>)
276{
277    __invoke(_VSTD::move(_VSTD::get<1>(__t)), _VSTD::move(_VSTD::get<_Indices>(__t))...);
278}
279
280template <class _Fp>
281void* __thread_proxy(void* __vp)
282{
283    // _Fp = std::tuple< unique_ptr<__thread_struct>, Functor, Args...>
284    std::unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
285    __thread_local_data().set_pointer(_VSTD::get<0>(*__p).release());
286    typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 2>::type _Index;
287    __thread_execute(*__p, _Index());
288    return nullptr;
289}
290
291template <class _Fp, class ..._Args,
292          class
293         >
294thread::thread(_Fp&& __f, _Args&&... __args)
295{
296    typedef unique_ptr<__thread_struct> _TSPtr;
297    _TSPtr __tsp(new __thread_struct);
298    typedef tuple<_TSPtr, typename decay<_Fp>::type, typename decay<_Args>::type...> _Gp;
299    _VSTD::unique_ptr<_Gp> __p(
300            new _Gp(std::move(__tsp),
301                    __decay_copy(_VSTD::forward<_Fp>(__f)),
302                    __decay_copy(_VSTD::forward<_Args>(__args))...));
303    int __ec = __libcpp_thread_create(&__t_, &__thread_proxy<_Gp>, __p.get());
304    if (__ec == 0)
305        __p.release();
306    else
307        __throw_system_error(__ec, "thread constructor failed");
308}
309
310inline
311thread&
312thread::operator=(thread&& __t) _NOEXCEPT
313{
314    if (!__libcpp_thread_isnull(&__t_))
315        terminate();
316    __t_ = __t.__t_;
317    __t.__t_ = _LIBCPP_NULL_THREAD;
318    return *this;
319}
320
321#else  // _LIBCPP_CXX03_LANG
322
323template <class _Fp>
324struct __thread_invoke_pair {
325    // This type is used to pass memory for thread local storage and a functor
326    // to a newly created thread because std::pair doesn't work with
327    // std::unique_ptr in C++03.
328    __thread_invoke_pair(_Fp& __f) : __tsp_(new __thread_struct), __fn_(__f) {}
329    unique_ptr<__thread_struct> __tsp_;
330    _Fp __fn_;
331};
332
333template <class _Fp>
334void* __thread_proxy_cxx03(void* __vp)
335{
336    std::unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
337    __thread_local_data().set_pointer(__p->__tsp_.release());
338    (__p->__fn_)();
339    return nullptr;
340}
341
342template <class _Fp>
343thread::thread(_Fp __f)
344{
345
346    typedef __thread_invoke_pair<_Fp> _InvokePair;
347    typedef std::unique_ptr<_InvokePair> _PairPtr;
348    _PairPtr __pp(new _InvokePair(__f));
349    int __ec = __libcpp_thread_create(&__t_, &__thread_proxy_cxx03<_InvokePair>, __pp.get());
350    if (__ec == 0)
351        __pp.release();
352    else
353        __throw_system_error(__ec, "thread constructor failed");
354}
355
356#endif  // _LIBCPP_CXX03_LANG
357
358inline _LIBCPP_INLINE_VISIBILITY
359void swap(thread& __x, thread& __y) _NOEXCEPT {__x.swap(__y);}
360
361namespace this_thread
362{
363
364_LIBCPP_FUNC_VIS void sleep_for(const chrono::nanoseconds& __ns);
365
366template <class _Rep, class _Period>
367void
368sleep_for(const chrono::duration<_Rep, _Period>& __d)
369{
370    using namespace chrono;
371    if (__d > duration<_Rep, _Period>::zero())
372    {
373#if defined(_LIBCPP_COMPILER_GCC) && (__powerpc__ || __POWERPC__)
374    //  GCC's long double const folding is incomplete for IBM128 long doubles.
375        _LIBCPP_CONSTEXPR duration<long double> _Max = nanoseconds::max();
376#else
377        _LIBCPP_CONSTEXPR duration<long double> _Max = duration<long double>(ULLONG_MAX/1000000000ULL) ;
378#endif
379        nanoseconds __ns;
380        if (__d < _Max)
381        {
382            __ns = duration_cast<nanoseconds>(__d);
383            if (__ns < __d)
384                ++__ns;
385        }
386        else
387            __ns = nanoseconds::max();
388        sleep_for(__ns);
389    }
390}
391
392template <class _Clock, class _Duration>
393void
394sleep_until(const chrono::time_point<_Clock, _Duration>& __t)
395{
396    using namespace chrono;
397    mutex __mut;
398    condition_variable __cv;
399    unique_lock<mutex> __lk(__mut);
400    while (_Clock::now() < __t)
401        __cv.wait_until(__lk, __t);
402}
403
404template <class _Duration>
405inline _LIBCPP_INLINE_VISIBILITY
406void
407sleep_until(const chrono::time_point<chrono::steady_clock, _Duration>& __t)
408{
409    using namespace chrono;
410    sleep_for(__t - steady_clock::now());
411}
412
413inline _LIBCPP_INLINE_VISIBILITY
414void yield() _NOEXCEPT {__libcpp_thread_yield();}
415
416}  // this_thread
417
418_LIBCPP_END_NAMESPACE_STD
419
420#endif // !_LIBCPP_HAS_NO_THREADS
421
422_LIBCPP_POP_MACROS
423
424#endif  // _LIBCPP_THREAD
425