1//===------------------------- thread.cpp----------------------------------===// 2// 3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4// See https://llvm.org/LICENSE.txt for license information. 5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6// 7//===----------------------------------------------------------------------===// 8 9#include <__config> 10 11#ifndef _LIBCPP_HAS_NO_THREADS 12 13#include <exception> 14#include <future> 15#include <limits> 16#include <thread> 17#include <vector> 18 19#if __has_include(<unistd.h>) 20# include <unistd.h> // for sysconf 21#endif 22 23#if defined(__NetBSD__) 24#pragma weak pthread_create // Do not create libpthread dependency 25#endif 26 27#if defined(_LIBCPP_WIN32API) 28#include <windows.h> 29#endif 30 31#if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB) 32#pragma comment(lib, "pthread") 33#endif 34 35_LIBCPP_BEGIN_NAMESPACE_STD 36 37thread::~thread() 38{ 39 if (!__libcpp_thread_isnull(&__t_)) 40 terminate(); 41} 42 43void 44thread::join() 45{ 46 int ec = EINVAL; 47 if (!__libcpp_thread_isnull(&__t_)) 48 { 49 ec = __libcpp_thread_join(&__t_); 50 if (ec == 0) 51 __t_ = _LIBCPP_NULL_THREAD; 52 } 53 54 if (ec) 55 __throw_system_error(ec, "thread::join failed"); 56} 57 58void 59thread::detach() 60{ 61 int ec = EINVAL; 62 if (!__libcpp_thread_isnull(&__t_)) 63 { 64 ec = __libcpp_thread_detach(&__t_); 65 if (ec == 0) 66 __t_ = _LIBCPP_NULL_THREAD; 67 } 68 69 if (ec) 70 __throw_system_error(ec, "thread::detach failed"); 71} 72 73unsigned 74thread::hardware_concurrency() noexcept 75{ 76#if defined(_SC_NPROCESSORS_ONLN) 77 long result = sysconf(_SC_NPROCESSORS_ONLN); 78 // sysconf returns -1 if the name is invalid, the option does not exist or 79 // does not have a definite limit. 80 // if sysconf returns some other negative number, we have no idea 81 // what is going on. Default to something safe. 82 if (result < 0) 83 return 0; 84 return static_cast<unsigned>(result); 85#elif defined(_LIBCPP_WIN32API) 86 SYSTEM_INFO info; 87 GetSystemInfo(&info); 88 return info.dwNumberOfProcessors; 89#else // defined(CTL_HW) && defined(HW_NCPU) 90 // TODO: grovel through /proc or check cpuid on x86 and similar 91 // instructions on other architectures. 92# if defined(_LIBCPP_WARNING) 93 _LIBCPP_WARNING("hardware_concurrency not yet implemented") 94# else 95# warning hardware_concurrency not yet implemented 96# endif 97 return 0; // Means not computable [thread.thread.static] 98#endif // defined(CTL_HW) && defined(HW_NCPU) 99} 100 101namespace this_thread 102{ 103 104void 105sleep_for(const chrono::nanoseconds& ns) 106{ 107 if (ns > chrono::nanoseconds::zero()) 108 { 109 __libcpp_thread_sleep_for(ns); 110 } 111} 112 113} // this_thread 114 115__thread_specific_ptr<__thread_struct>& 116__thread_local_data() 117{ 118 // Even though __thread_specific_ptr's destructor doesn't actually destroy 119 // anything (see comments there), we can't call it at all because threads may 120 // outlive the static variable and calling its destructor means accessing an 121 // object outside of its lifetime, which is UB. 122 alignas(__thread_specific_ptr<__thread_struct>) static char __b[sizeof(__thread_specific_ptr<__thread_struct>)]; 123 static __thread_specific_ptr<__thread_struct>* __p = new (__b) __thread_specific_ptr<__thread_struct>(); 124 return *__p; 125} 126 127// __thread_struct_imp 128 129template <class T> 130class _LIBCPP_HIDDEN __hidden_allocator 131{ 132public: 133 typedef T value_type; 134 135 T* allocate(size_t __n) 136 {return static_cast<T*>(::operator new(__n * sizeof(T)));} 137 void deallocate(T* __p, size_t) {::operator delete(static_cast<void*>(__p));} 138 139 size_t max_size() const {return size_t(~0) / sizeof(T);} 140}; 141 142class _LIBCPP_HIDDEN __thread_struct_imp 143{ 144 typedef vector<__assoc_sub_state*, 145 __hidden_allocator<__assoc_sub_state*> > _AsyncStates; 146 typedef vector<pair<condition_variable*, mutex*>, 147 __hidden_allocator<pair<condition_variable*, mutex*> > > _Notify; 148 149 _AsyncStates async_states_; 150 _Notify notify_; 151 152 __thread_struct_imp(const __thread_struct_imp&); 153 __thread_struct_imp& operator=(const __thread_struct_imp&); 154public: 155 __thread_struct_imp() {} 156 ~__thread_struct_imp(); 157 158 void notify_all_at_thread_exit(condition_variable* cv, mutex* m); 159 void __make_ready_at_thread_exit(__assoc_sub_state* __s); 160}; 161 162__thread_struct_imp::~__thread_struct_imp() 163{ 164 for (_Notify::iterator i = notify_.begin(), e = notify_.end(); 165 i != e; ++i) 166 { 167 i->first->notify_all(); 168 i->second->unlock(); 169 } 170 for (_AsyncStates::iterator i = async_states_.begin(), e = async_states_.end(); 171 i != e; ++i) 172 { 173 (*i)->__make_ready(); 174 (*i)->__release_shared(); 175 } 176} 177 178void 179__thread_struct_imp::notify_all_at_thread_exit(condition_variable* cv, mutex* m) 180{ 181 notify_.push_back(pair<condition_variable*, mutex*>(cv, m)); 182} 183 184void 185__thread_struct_imp::__make_ready_at_thread_exit(__assoc_sub_state* __s) 186{ 187 async_states_.push_back(__s); 188 __s->__add_shared(); 189} 190 191// __thread_struct 192 193__thread_struct::__thread_struct() 194 : __p_(new __thread_struct_imp) 195{ 196} 197 198__thread_struct::~__thread_struct() 199{ 200 delete __p_; 201} 202 203void 204__thread_struct::notify_all_at_thread_exit(condition_variable* cv, mutex* m) 205{ 206 __p_->notify_all_at_thread_exit(cv, m); 207} 208 209void 210__thread_struct::__make_ready_at_thread_exit(__assoc_sub_state* __s) 211{ 212 __p_->__make_ready_at_thread_exit(__s); 213} 214 215_LIBCPP_END_NAMESPACE_STD 216 217#endif // !_LIBCPP_HAS_NO_THREADS 218