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 <__thread/support.h>
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_PUSH_MACROS
36 #include <__undef_macros>
37
38 _LIBCPP_BEGIN_NAMESPACE_STD
39
40 template <class _Tp>
41 class __thread_specific_ptr;
42 class _LIBCPP_EXPORTED_FROM_ABI __thread_struct;
43 class _LIBCPP_HIDDEN __thread_struct_imp;
44 class __assoc_sub_state;
45
46 _LIBCPP_EXPORTED_FROM_ABI __thread_specific_ptr<__thread_struct>& __thread_local_data();
47
48 class _LIBCPP_EXPORTED_FROM_ABI __thread_struct {
49 __thread_struct_imp* __p_;
50
51 __thread_struct(const __thread_struct&);
52 __thread_struct& operator=(const __thread_struct&);
53
54 public:
55 __thread_struct();
56 ~__thread_struct();
57
58 void notify_all_at_thread_exit(condition_variable*, mutex*);
59 void __make_ready_at_thread_exit(__assoc_sub_state*);
60 };
61
62 template <class _Tp>
63 class __thread_specific_ptr {
64 __libcpp_tls_key __key_;
65
66 // Only __thread_local_data() may construct a __thread_specific_ptr
67 // and only with _Tp == __thread_struct.
68 static_assert((is_same<_Tp, __thread_struct>::value), "");
69 __thread_specific_ptr();
70 friend _LIBCPP_EXPORTED_FROM_ABI __thread_specific_ptr<__thread_struct>& __thread_local_data();
71
72 __thread_specific_ptr(const __thread_specific_ptr&);
73 __thread_specific_ptr& operator=(const __thread_specific_ptr&);
74
75 _LIBCPP_HIDDEN static void _LIBCPP_TLS_DESTRUCTOR_CC __at_thread_exit(void*);
76
77 public:
78 typedef _Tp* pointer;
79
80 ~__thread_specific_ptr();
81
get()82 _LIBCPP_HIDE_FROM_ABI pointer get() const { return static_cast<_Tp*>(__libcpp_tls_get(__key_)); }
83 _LIBCPP_HIDE_FROM_ABI pointer operator*() const { return *get(); }
84 _LIBCPP_HIDE_FROM_ABI pointer operator->() const { return get(); }
85 void set_pointer(pointer __p);
86 };
87
88 template <class _Tp>
__at_thread_exit(void * __p)89 void _LIBCPP_TLS_DESTRUCTOR_CC __thread_specific_ptr<_Tp>::__at_thread_exit(void* __p) {
90 delete static_cast<pointer>(__p);
91 }
92
93 template <class _Tp>
__thread_specific_ptr()94 __thread_specific_ptr<_Tp>::__thread_specific_ptr() {
95 int __ec = __libcpp_tls_create(&__key_, &__thread_specific_ptr::__at_thread_exit);
96 if (__ec)
97 __throw_system_error(__ec, "__thread_specific_ptr construction failed");
98 }
99
100 template <class _Tp>
~__thread_specific_ptr()101 __thread_specific_ptr<_Tp>::~__thread_specific_ptr() {
102 // __thread_specific_ptr is only created with a static storage duration
103 // so this destructor is only invoked during program termination. Invoking
104 // pthread_key_delete(__key_) may prevent other threads from deleting their
105 // thread local data. For this reason we leak the key.
106 }
107
108 template <class _Tp>
set_pointer(pointer __p)109 void __thread_specific_ptr<_Tp>::set_pointer(pointer __p) {
110 _LIBCPP_ASSERT_INTERNAL(get() == nullptr, "Attempting to overwrite thread local data");
111 std::__libcpp_tls_set(__key_, __p);
112 }
113
114 template <>
115 struct _LIBCPP_TEMPLATE_VIS hash<__thread_id> : public __unary_function<__thread_id, size_t> {
116 _LIBCPP_HIDE_FROM_ABI size_t operator()(__thread_id __v) const _NOEXCEPT {
117 return hash<__libcpp_thread_id>()(__v.__id_);
118 }
119 };
120
121 #ifndef _LIBCPP_HAS_NO_LOCALIZATION
122 template <class _CharT, class _Traits>
123 _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
124 operator<<(basic_ostream<_CharT, _Traits>& __os, __thread_id __id) {
125 // [thread.thread.id]/9
126 // Effects: Inserts the text representation for charT of id into out.
127 //
128 // [thread.thread.id]/2
129 // The text representation for the character type charT of an
130 // object of type thread::id is an unspecified sequence of charT
131 // such that, for two objects of type thread::id x and y, if
132 // x == y is true, the thread::id objects have the same text
133 // representation, and if x != y is true, the thread::id objects
134 // have distinct text representations.
135 //
136 // Since various flags in the output stream can affect how the
137 // thread id is represented (e.g. numpunct or showbase), we
138 // use a temporary stream instead and just output the thread
139 // id representation as a string.
140
141 basic_ostringstream<_CharT, _Traits> __sstr;
142 __sstr.imbue(locale::classic());
143 __sstr << __id.__id_;
144 return __os << __sstr.str();
145 }
146 #endif // _LIBCPP_HAS_NO_LOCALIZATION
147
148 class _LIBCPP_EXPORTED_FROM_ABI thread {
149 __libcpp_thread_t __t_;
150
151 thread(const thread&);
152 thread& operator=(const thread&);
153
154 public:
155 typedef __thread_id id;
156 typedef __libcpp_thread_t native_handle_type;
157
158 _LIBCPP_HIDE_FROM_ABI thread() _NOEXCEPT : __t_(_LIBCPP_NULL_THREAD) {}
159 #ifndef _LIBCPP_CXX03_LANG
160 template <class _Fp, class... _Args, __enable_if_t<!is_same<__remove_cvref_t<_Fp>, thread>::value, int> = 0>
161 _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS explicit thread(_Fp&& __f, _Args&&... __args);
162 #else // _LIBCPP_CXX03_LANG
163 template <class _Fp>
164 _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS explicit thread(_Fp __f);
165 #endif
166 ~thread();
167
168 _LIBCPP_HIDE_FROM_ABI thread(thread&& __t) _NOEXCEPT : __t_(__t.__t_) { __t.__t_ = _LIBCPP_NULL_THREAD; }
169
170 _LIBCPP_HIDE_FROM_ABI thread& operator=(thread&& __t) _NOEXCEPT {
171 if (!__libcpp_thread_isnull(&__t_))
172 terminate();
173 __t_ = __t.__t_;
174 __t.__t_ = _LIBCPP_NULL_THREAD;
175 return *this;
176 }
177
178 _LIBCPP_HIDE_FROM_ABI void swap(thread& __t) _NOEXCEPT { std::swap(__t_, __t.__t_); }
179
180 _LIBCPP_HIDE_FROM_ABI bool joinable() const _NOEXCEPT { return !__libcpp_thread_isnull(&__t_); }
181 void join();
182 void detach();
183 _LIBCPP_HIDE_FROM_ABI id get_id() const _NOEXCEPT { return __libcpp_thread_get_id(&__t_); }
184 _LIBCPP_HIDE_FROM_ABI native_handle_type native_handle() _NOEXCEPT { return __t_; }
185
186 static unsigned hardware_concurrency() _NOEXCEPT;
187 };
188
189 #ifndef _LIBCPP_CXX03_LANG
190
191 template <class _TSp, class _Fp, class... _Args, size_t... _Indices>
192 inline _LIBCPP_HIDE_FROM_ABI void __thread_execute(tuple<_TSp, _Fp, _Args...>& __t, __tuple_indices<_Indices...>) {
193 std::__invoke(std::move(std::get<1>(__t)), std::move(std::get<_Indices>(__t))...);
194 }
195
196 template <class _Fp>
197 _LIBCPP_HIDE_FROM_ABI void* __thread_proxy(void* __vp) {
198 // _Fp = tuple< unique_ptr<__thread_struct>, Functor, Args...>
199 unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
200 __thread_local_data().set_pointer(std::get<0>(*__p.get()).release());
201 typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 2>::type _Index;
202 std::__thread_execute(*__p.get(), _Index());
203 return nullptr;
204 }
205
206 template <class _Fp, class... _Args, __enable_if_t<!is_same<__remove_cvref_t<_Fp>, thread>::value, int> >
207 thread::thread(_Fp&& __f, _Args&&... __args) {
208 typedef unique_ptr<__thread_struct> _TSPtr;
209 _TSPtr __tsp(new __thread_struct);
210 typedef tuple<_TSPtr, __decay_t<_Fp>, __decay_t<_Args>...> _Gp;
211 unique_ptr<_Gp> __p(new _Gp(std::move(__tsp), std::forward<_Fp>(__f), std::forward<_Args>(__args)...));
212 int __ec = std::__libcpp_thread_create(&__t_, &__thread_proxy<_Gp>, __p.get());
213 if (__ec == 0)
214 __p.release();
215 else
216 __throw_system_error(__ec, "thread constructor failed");
217 }
218
219 #else // _LIBCPP_CXX03_LANG
220
221 template <class _Fp>
222 struct __thread_invoke_pair {
223 // This type is used to pass memory for thread local storage and a functor
224 // to a newly created thread because std::pair doesn't work with
225 // std::unique_ptr in C++03.
226 _LIBCPP_HIDE_FROM_ABI __thread_invoke_pair(_Fp& __f) : __tsp_(new __thread_struct), __fn_(__f) {}
227 unique_ptr<__thread_struct> __tsp_;
228 _Fp __fn_;
229 };
230
231 template <class _Fp>
232 _LIBCPP_HIDE_FROM_ABI void* __thread_proxy_cxx03(void* __vp) {
233 unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
234 __thread_local_data().set_pointer(__p->__tsp_.release());
235 (__p->__fn_)();
236 return nullptr;
237 }
238
239 template <class _Fp>
240 thread::thread(_Fp __f) {
241 typedef __thread_invoke_pair<_Fp> _InvokePair;
242 typedef unique_ptr<_InvokePair> _PairPtr;
243 _PairPtr __pp(new _InvokePair(__f));
244 int __ec = std::__libcpp_thread_create(&__t_, &__thread_proxy_cxx03<_InvokePair>, __pp.get());
245 if (__ec == 0)
246 __pp.release();
247 else
248 __throw_system_error(__ec, "thread constructor failed");
249 }
250
251 #endif // _LIBCPP_CXX03_LANG
252
253 inline _LIBCPP_HIDE_FROM_ABI void swap(thread& __x, thread& __y) _NOEXCEPT { __x.swap(__y); }
254
255 _LIBCPP_END_NAMESPACE_STD
256
257 _LIBCPP_POP_MACROS
258
259 #endif // _LIBCPP___THREAD_THREAD_H
260