1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
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_THREAD_H
11 #define _LIBCPP___THREAD_THREAD_H
12
13 #include <__condition_variable/condition_variable.h>
14 #include <__config>
15 #include <__exception/terminate.h>
16 #include <__functional/hash.h>
17 #include <__functional/unary_function.h>
18 #include <__memory/unique_ptr.h>
19 #include <__mutex/mutex.h>
20 #include <__system_error/system_error.h>
21 #include <__thread/id.h>
22 #include <__threading_support>
23 #include <__utility/forward.h>
24 #include <tuple>
25
26 #ifndef _LIBCPP_HAS_NO_LOCALIZATION
27 # include <locale>
28 # include <sstream>
29 #endif
30
31 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
32 # pragma GCC system_header
33 #endif
34
35 _LIBCPP_BEGIN_NAMESPACE_STD
36
37 template <class _Tp>
38 class __thread_specific_ptr;
39 class _LIBCPP_EXPORTED_FROM_ABI __thread_struct;
40 class _LIBCPP_HIDDEN __thread_struct_imp;
41 class __assoc_sub_state;
42
43 _LIBCPP_EXPORTED_FROM_ABI __thread_specific_ptr<__thread_struct>& __thread_local_data();
44
45 class _LIBCPP_EXPORTED_FROM_ABI __thread_struct {
46 __thread_struct_imp* __p_;
47
48 __thread_struct(const __thread_struct&);
49 __thread_struct& operator=(const __thread_struct&);
50
51 public:
52 __thread_struct();
53 ~__thread_struct();
54
55 void notify_all_at_thread_exit(condition_variable*, mutex*);
56 void __make_ready_at_thread_exit(__assoc_sub_state*);
57 };
58
59 template <class _Tp>
60 class __thread_specific_ptr {
61 __libcpp_tls_key __key_;
62
63 // Only __thread_local_data() may construct a __thread_specific_ptr
64 // and only with _Tp == __thread_struct.
65 static_assert((is_same<_Tp, __thread_struct>::value), "");
66 __thread_specific_ptr();
67 friend _LIBCPP_EXPORTED_FROM_ABI __thread_specific_ptr<__thread_struct>& __thread_local_data();
68
69 __thread_specific_ptr(const __thread_specific_ptr&);
70 __thread_specific_ptr& operator=(const __thread_specific_ptr&);
71
72 _LIBCPP_HIDDEN static void _LIBCPP_TLS_DESTRUCTOR_CC __at_thread_exit(void*);
73
74 public:
75 typedef _Tp* pointer;
76
77 ~__thread_specific_ptr();
78
get()79 _LIBCPP_HIDE_FROM_ABI pointer get() const { return static_cast<_Tp*>(__libcpp_tls_get(__key_)); }
80 _LIBCPP_HIDE_FROM_ABI pointer operator*() const { return *get(); }
81 _LIBCPP_HIDE_FROM_ABI pointer operator->() const { return get(); }
82 void set_pointer(pointer __p);
83 };
84
85 template <class _Tp>
__at_thread_exit(void * __p)86 void _LIBCPP_TLS_DESTRUCTOR_CC __thread_specific_ptr<_Tp>::__at_thread_exit(void* __p) {
87 delete static_cast<pointer>(__p);
88 }
89
90 template <class _Tp>
__thread_specific_ptr()91 __thread_specific_ptr<_Tp>::__thread_specific_ptr() {
92 int __ec = __libcpp_tls_create(&__key_, &__thread_specific_ptr::__at_thread_exit);
93 if (__ec)
94 __throw_system_error(__ec, "__thread_specific_ptr construction failed");
95 }
96
97 template <class _Tp>
~__thread_specific_ptr()98 __thread_specific_ptr<_Tp>::~__thread_specific_ptr() {
99 // __thread_specific_ptr is only created with a static storage duration
100 // so this destructor is only invoked during program termination. Invoking
101 // pthread_key_delete(__key_) may prevent other threads from deleting their
102 // thread local data. For this reason we leak the key.
103 }
104
105 template <class _Tp>
set_pointer(pointer __p)106 void __thread_specific_ptr<_Tp>::set_pointer(pointer __p) {
107 _LIBCPP_ASSERT_UNCATEGORIZED(get() == nullptr, "Attempting to overwrite thread local data");
108 std::__libcpp_tls_set(__key_, __p);
109 }
110
111 template <>
112 struct _LIBCPP_TEMPLATE_VIS hash<__thread_id> : public __unary_function<__thread_id, size_t> {
113 _LIBCPP_HIDE_FROM_ABI size_t operator()(__thread_id __v) const _NOEXCEPT {
114 return hash<__libcpp_thread_id>()(__v.__id_);
115 }
116 };
117
118 #ifndef _LIBCPP_HAS_NO_LOCALIZATION
119 template <class _CharT, class _Traits>
120 _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
121 operator<<(basic_ostream<_CharT, _Traits>& __os, __thread_id __id) {
122 // [thread.thread.id]/9
123 // Effects: Inserts the text representation for charT of id into out.
124 //
125 // [thread.thread.id]/2
126 // The text representation for the character type charT of an
127 // object of type thread::id is an unspecified sequence of charT
128 // such that, for two objects of type thread::id x and y, if
129 // x == y is true, the thread::id objects have the same text
130 // representation, and if x != y is true, the thread::id objects
131 // have distinct text representations.
132 //
133 // Since various flags in the output stream can affect how the
134 // thread id is represented (e.g. numpunct or showbase), we
135 // use a temporary stream instead and just output the thread
136 // id representation as a string.
137
138 basic_ostringstream<_CharT, _Traits> __sstr;
139 __sstr.imbue(locale::classic());
140 __sstr << __id.__id_;
141 return __os << __sstr.str();
142 }
143 #endif // _LIBCPP_HAS_NO_LOCALIZATION
144
145 class _LIBCPP_EXPORTED_FROM_ABI thread {
146 __libcpp_thread_t __t_;
147
148 thread(const thread&);
149 thread& operator=(const thread&);
150
151 public:
152 typedef __thread_id id;
153 typedef __libcpp_thread_t native_handle_type;
154
155 _LIBCPP_HIDE_FROM_ABI thread() _NOEXCEPT : __t_(_LIBCPP_NULL_THREAD) {}
156 #ifndef _LIBCPP_CXX03_LANG
157 template <class _Fp, class... _Args, class = __enable_if_t<!is_same<__remove_cvref_t<_Fp>, thread>::value> >
158 _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS explicit thread(_Fp&& __f, _Args&&... __args);
159 #else // _LIBCPP_CXX03_LANG
160 template <class _Fp>
161 _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS explicit thread(_Fp __f);
162 #endif
163 ~thread();
164
165 _LIBCPP_HIDE_FROM_ABI thread(thread&& __t) _NOEXCEPT : __t_(__t.__t_) { __t.__t_ = _LIBCPP_NULL_THREAD; }
166
167 _LIBCPP_HIDE_FROM_ABI thread& operator=(thread&& __t) _NOEXCEPT {
168 if (!__libcpp_thread_isnull(&__t_))
169 terminate();
170 __t_ = __t.__t_;
171 __t.__t_ = _LIBCPP_NULL_THREAD;
172 return *this;
173 }
174
175 _LIBCPP_HIDE_FROM_ABI void swap(thread& __t) _NOEXCEPT { std::swap(__t_, __t.__t_); }
176
177 _LIBCPP_HIDE_FROM_ABI bool joinable() const _NOEXCEPT { return !__libcpp_thread_isnull(&__t_); }
178 void join();
179 void detach();
180 _LIBCPP_HIDE_FROM_ABI id get_id() const _NOEXCEPT { return __libcpp_thread_get_id(&__t_); }
181 _LIBCPP_HIDE_FROM_ABI native_handle_type native_handle() _NOEXCEPT { return __t_; }
182
183 static unsigned hardware_concurrency() _NOEXCEPT;
184 };
185
186 #ifndef _LIBCPP_CXX03_LANG
187
188 template <class _TSp, class _Fp, class... _Args, size_t... _Indices>
189 inline _LIBCPP_HIDE_FROM_ABI void __thread_execute(tuple<_TSp, _Fp, _Args...>& __t, __tuple_indices<_Indices...>) {
190 std::__invoke(std::move(std::get<1>(__t)), std::move(std::get<_Indices>(__t))...);
191 }
192
193 template <class _Fp>
194 _LIBCPP_HIDE_FROM_ABI void* __thread_proxy(void* __vp) {
195 // _Fp = tuple< unique_ptr<__thread_struct>, Functor, Args...>
196 unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
197 __thread_local_data().set_pointer(std::get<0>(*__p.get()).release());
198 typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 2>::type _Index;
199 std::__thread_execute(*__p.get(), _Index());
200 return nullptr;
201 }
202
203 template <class _Fp, class... _Args, class >
204 thread::thread(_Fp&& __f, _Args&&... __args) {
205 typedef unique_ptr<__thread_struct> _TSPtr;
206 _TSPtr __tsp(new __thread_struct);
207 typedef tuple<_TSPtr, __decay_t<_Fp>, __decay_t<_Args>...> _Gp;
208 unique_ptr<_Gp> __p(new _Gp(std::move(__tsp), std::forward<_Fp>(__f), std::forward<_Args>(__args)...));
209 int __ec = std::__libcpp_thread_create(&__t_, &__thread_proxy<_Gp>, __p.get());
210 if (__ec == 0)
211 __p.release();
212 else
213 __throw_system_error(__ec, "thread constructor failed");
214 }
215
216 #else // _LIBCPP_CXX03_LANG
217
218 template <class _Fp>
219 struct __thread_invoke_pair {
220 // This type is used to pass memory for thread local storage and a functor
221 // to a newly created thread because std::pair doesn't work with
222 // std::unique_ptr in C++03.
223 _LIBCPP_HIDE_FROM_ABI __thread_invoke_pair(_Fp& __f) : __tsp_(new __thread_struct), __fn_(__f) {}
224 unique_ptr<__thread_struct> __tsp_;
225 _Fp __fn_;
226 };
227
228 template <class _Fp>
229 _LIBCPP_HIDE_FROM_ABI void* __thread_proxy_cxx03(void* __vp) {
230 unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
231 __thread_local_data().set_pointer(__p->__tsp_.release());
232 (__p->__fn_)();
233 return nullptr;
234 }
235
236 template <class _Fp>
237 thread::thread(_Fp __f) {
238 typedef __thread_invoke_pair<_Fp> _InvokePair;
239 typedef unique_ptr<_InvokePair> _PairPtr;
240 _PairPtr __pp(new _InvokePair(__f));
241 int __ec = std::__libcpp_thread_create(&__t_, &__thread_proxy_cxx03<_InvokePair>, __pp.get());
242 if (__ec == 0)
243 __pp.release();
244 else
245 __throw_system_error(__ec, "thread constructor failed");
246 }
247
248 #endif // _LIBCPP_CXX03_LANG
249
250 inline _LIBCPP_HIDE_FROM_ABI void swap(thread& __x, thread& __y) _NOEXCEPT { __x.swap(__y); }
251
252 _LIBCPP_END_NAMESPACE_STD
253
254 #endif // _LIBCPP___THREAD_THREAD_H
255