__cxx03/__thread/thread.h

0001 // -*- C++ -*-
0002 //===----------------------------------------------------------------------===//
0003 //
0004 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0005 // See https://llvm.org/LICENSE.txt for license information.
0006 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0007 //
0008 //===----------------------------------------------------------------------===//
0009
0010 #ifndef _LIBCPP___CXX03___THREAD_THREAD_H
0011 #define _LIBCPP___CXX03___THREAD_THREAD_H
0012
0013 #include <__cxx03/__condition_variable/condition_variable.h>
0014 #include <__cxx03/__config>
0015 #include <__cxx03/__exception/terminate.h>
0016 #include <__cxx03/__functional/hash.h>
0017 #include <__cxx03/__functional/unary_function.h>
0018 #include <__cxx03/__memory/unique_ptr.h>
0019 #include <__cxx03/__mutex/mutex.h>
0020 #include <__cxx03/__system_error/system_error.h>
0021 #include <__cxx03/__thread/id.h>
0022 #include <__cxx03/__thread/support.h>
0023 #include <__cxx03/__utility/forward.h>
0024 #include <__cxx03/tuple>
0025
0026 #ifndef _LIBCPP_HAS_NO_LOCALIZATION
0027 #  include <__cxx03/locale>
0028 #  include <__cxx03/sstream>
0029 #endif
0030
0031 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0032 #  pragma GCC system_header
0033 #endif
0034
0035 _LIBCPP_PUSH_MACROS
0036 #include <__cxx03/__undef_macros>
0037
0038 _LIBCPP_BEGIN_NAMESPACE_STD
0039
0040 template <class _Tp>
0041 class __thread_specific_ptr;
0042 class _LIBCPP_EXPORTED_FROM_ABI __thread_struct;
0043 class _LIBCPP_HIDDEN __thread_struct_imp;
0044 class __assoc_sub_state;
0045
0046 _LIBCPP_EXPORTED_FROM_ABI __thread_specific_ptr<__thread_struct>& __thread_local_data();
0047
0048 class _LIBCPP_EXPORTED_FROM_ABI __thread_struct {
0049   __thread_struct_imp* __p_;
0050
0051   __thread_struct(const __thread_struct&);
0052   __thread_struct& operator=(const __thread_struct&);
0053
0054 public:
0055   __thread_struct();
0056   ~__thread_struct();
0057
0058   void notify_all_at_thread_exit(condition_variable*, mutex*);
0059   void __make_ready_at_thread_exit(__assoc_sub_state*);
0060 };
0061
0062 template <class _Tp>
0063 class __thread_specific_ptr {
0064   __libcpp_tls_key __key_;
0065
0066   // Only __thread_local_data() may construct a __thread_specific_ptr
0067   // and only with _Tp == __thread_struct.
0068   static_assert(is_same<_Tp, __thread_struct>::value, "");
0069   __thread_specific_ptr();
0070   friend _LIBCPP_EXPORTED_FROM_ABI __thread_specific_ptr<__thread_struct>& __thread_local_data();
0071
0072   _LIBCPP_HIDDEN static void _LIBCPP_TLS_DESTRUCTOR_CC __at_thread_exit(void*);
0073
0074 public:
0075   typedef _Tp* pointer;
0076
0077   __thread_specific_ptr(const __thread_specific_ptr&)            = delete;
0078   __thread_specific_ptr& operator=(const __thread_specific_ptr&) = delete;
0079   ~__thread_specific_ptr();
0080
0081   _LIBCPP_HIDE_FROM_ABI pointer get() const { return static_cast<_Tp*>(__libcpp_tls_get(__key_)); }
0082   _LIBCPP_HIDE_FROM_ABI pointer operator*() const { return *get(); }
0083   _LIBCPP_HIDE_FROM_ABI pointer operator->() const { return get(); }
0084   void set_pointer(pointer __p);
0085 };
0086
0087 template <class _Tp>
0088 void _LIBCPP_TLS_DESTRUCTOR_CC __thread_specific_ptr<_Tp>::__at_thread_exit(void* __p) {
0089   delete static_cast<pointer>(__p);
0090 }
0091
0092 template <class _Tp>
0093 __thread_specific_ptr<_Tp>::__thread_specific_ptr() {
0094   int __ec = __libcpp_tls_create(&__key_, &__thread_specific_ptr::__at_thread_exit);
0095   if (__ec)
0096     __throw_system_error(__ec, "__thread_specific_ptr construction failed");
0097 }
0098
0099 template <class _Tp>
0100 __thread_specific_ptr<_Tp>::~__thread_specific_ptr() {
0101   // __thread_specific_ptr is only created with a static storage duration
0102   // so this destructor is only invoked during program termination. Invoking
0103   // pthread_key_delete(__key_) may prevent other threads from deleting their
0104   // thread local data. For this reason we leak the key.
0105 }
0106
0107 template <class _Tp>
0108 void __thread_specific_ptr<_Tp>::set_pointer(pointer __p) {
0109   _LIBCPP_ASSERT_INTERNAL(get() == nullptr, "Attempting to overwrite thread local data");
0110   std::__libcpp_tls_set(__key_, __p);
0111 }
0112
0113 template <>
0114 struct _LIBCPP_TEMPLATE_VIS hash<__thread_id> : public __unary_function<__thread_id, size_t> {
0115   _LIBCPP_HIDE_FROM_ABI size_t operator()(__thread_id __v) const _NOEXCEPT {
0116     return hash<__libcpp_thread_id>()(__v.__id_);
0117   }
0118 };
0119
0120 #ifndef _LIBCPP_HAS_NO_LOCALIZATION
0121 template <class _CharT, class _Traits>
0122 _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
0123 operator<<(basic_ostream<_CharT, _Traits>& __os, __thread_id __id) {
0124   // [thread.thread.id]/9
0125   //   Effects: Inserts the text representation for charT of id into out.
0126   //
0127   // [thread.thread.id]/2
0128   //   The text representation for the character type charT of an
0129   //   object of type thread::id is an unspecified sequence of charT
0130   //   such that, for two objects of type thread::id x and y, if
0131   //   x == y is true, the thread::id objects have the same text
0132   //   representation, and if x != y is true, the thread::id objects
0133   //   have distinct text representations.
0134   //
0135   // Since various flags in the output stream can affect how the
0136   // thread id is represented (e.g. numpunct or showbase), we
0137   // use a temporary stream instead and just output the thread
0138   // id representation as a string.
0139
0140   basic_ostringstream<_CharT, _Traits> __sstr;
0141   __sstr.imbue(locale::classic());
0142   __sstr << __id.__id_;
0143   return __os << __sstr.str();
0144 }
0145 #endif // _LIBCPP_HAS_NO_LOCALIZATION
0146
0147 class _LIBCPP_EXPORTED_FROM_ABI thread {
0148   __libcpp_thread_t __t_;
0149
0150   thread(const thread&);
0151   thread& operator=(const thread&);
0152
0153 public:
0154   typedef __thread_id id;
0155   typedef __libcpp_thread_t native_handle_type;
0156
0157   _LIBCPP_HIDE_FROM_ABI thread() _NOEXCEPT : __t_(_LIBCPP_NULL_THREAD) {}
0158 #ifndef _LIBCPP_CXX03_LANG
0159   template <class _Fp, class... _Args, __enable_if_t<!is_same<__remove_cvref_t<_Fp>, thread>::value, int> = 0>
0160   _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS explicit thread(_Fp&& __f, _Args&&... __args);
0161 #else // _LIBCPP_CXX03_LANG
0162   template <class _Fp>
0163   _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS explicit thread(_Fp __f);
0164 #endif
0165   ~thread();
0166
0167   _LIBCPP_HIDE_FROM_ABI thread(thread&& __t) _NOEXCEPT : __t_(__t.__t_) { __t.__t_ = _LIBCPP_NULL_THREAD; }
0168
0169   _LIBCPP_HIDE_FROM_ABI thread& operator=(thread&& __t) _NOEXCEPT {
0170     if (!__libcpp_thread_isnull(&__t_))
0171       terminate();
0172     __t_     = __t.__t_;
0173     __t.__t_ = _LIBCPP_NULL_THREAD;
0174     return *this;
0175   }
0176
0177   _LIBCPP_HIDE_FROM_ABI void swap(thread& __t) _NOEXCEPT { std::swap(__t_, __t.__t_); }
0178
0179   _LIBCPP_HIDE_FROM_ABI bool joinable() const _NOEXCEPT { return !__libcpp_thread_isnull(&__t_); }
0180   void join();
0181   void detach();
0182   _LIBCPP_HIDE_FROM_ABI id get_id() const _NOEXCEPT { return __libcpp_thread_get_id(&__t_); }
0183   _LIBCPP_HIDE_FROM_ABI native_handle_type native_handle() _NOEXCEPT { return __t_; }
0184
0185   static unsigned hardware_concurrency() _NOEXCEPT;
0186 };
0187
0188 #ifndef _LIBCPP_CXX03_LANG
0189
0190 template <class _TSp, class _Fp, class... _Args, size_t... _Indices>
0191 inline _LIBCPP_HIDE_FROM_ABI void __thread_execute(tuple<_TSp, _Fp, _Args...>& __t, __tuple_indices<_Indices...>) {
0192   std::__invoke(std::move(std::get<1>(__t)), std::move(std::get<_Indices>(__t))...);
0193 }
0194
0195 template <class _Fp>
0196 _LIBCPP_HIDE_FROM_ABI void* __thread_proxy(void* __vp) {
0197   // _Fp = tuple< unique_ptr<__thread_struct>, Functor, Args...>
0198   unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
0199   __thread_local_data().set_pointer(std::get<0>(*__p.get()).release());
0200   typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 2>::type _Index;
0201   std::__thread_execute(*__p.get(), _Index());
0202   return nullptr;
0203 }
0204
0205 template <class _Fp, class... _Args, __enable_if_t<!is_same<__remove_cvref_t<_Fp>, thread>::value, int> >
0206 thread::thread(_Fp&& __f, _Args&&... __args) {
0207   typedef unique_ptr<__thread_struct> _TSPtr;
0208   _TSPtr __tsp(new __thread_struct);
0209   typedef tuple<_TSPtr, __decay_t<_Fp>, __decay_t<_Args>...> _Gp;
0210   unique_ptr<_Gp> __p(new _Gp(std::move(__tsp), std::forward<_Fp>(__f), std::forward<_Args>(__args)...));
0211   int __ec = std::__libcpp_thread_create(&__t_, &__thread_proxy<_Gp>, __p.get());
0212   if (__ec == 0)
0213     __p.release();
0214   else
0215     __throw_system_error(__ec, "thread constructor failed");
0216 }
0217
0218 #else // _LIBCPP_CXX03_LANG
0219
0220 template <class _Fp>
0221 struct __thread_invoke_pair {
0222   // This type is used to pass memory for thread local storage and a functor
0223   // to a newly created thread because std::pair doesn't work with
0224   // std::unique_ptr in C++03.
0225   _LIBCPP_HIDE_FROM_ABI __thread_invoke_pair(_Fp& __f) : __tsp_(new __thread_struct), __fn_(__f) {}
0226   unique_ptr<__thread_struct> __tsp_;
0227   _Fp __fn_;
0228 };
0229
0230 template <class _Fp>
0231 _LIBCPP_HIDE_FROM_ABI void* __thread_proxy_cxx03(void* __vp) {
0232   unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
0233   __thread_local_data().set_pointer(__p->__tsp_.release());
0234   (__p->__fn_)();
0235   return nullptr;
0236 }
0237
0238 template <class _Fp>
0239 thread::thread(_Fp __f) {
0240   typedef __thread_invoke_pair<_Fp> _InvokePair;
0241   typedef unique_ptr<_InvokePair> _PairPtr;
0242   _PairPtr __pp(new _InvokePair(__f));
0243   int __ec = std::__libcpp_thread_create(&__t_, &__thread_proxy_cxx03<_InvokePair>, __pp.get());
0244   if (__ec == 0)
0245     __pp.release();
0246   else
0247     __throw_system_error(__ec, "thread constructor failed");
0248 }
0249
0250 #endif // _LIBCPP_CXX03_LANG
0251
0252 inline _LIBCPP_HIDE_FROM_ABI void swap(thread& __x, thread& __y) _NOEXCEPT { __x.swap(__y); }
0253
0254 _LIBCPP_END_NAMESPACE_STD
0255
0256 _LIBCPP_POP_MACROS
0257
0258 #endif // _LIBCPP___CXX03___THREAD_THREAD_H