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//===------------------------- thread.cpp----------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include <__config>
#ifndef _LIBCPP_HAS_NO_THREADS
#include <__thread/poll_with_backoff.h>
#include <__thread/timed_backoff_policy.h>
#include <exception>
#include <future>
#include <limits>
#include <thread>
#include <vector>
#if __has_include(<unistd.h>)
# include <unistd.h> // for sysconf
#endif
#if defined(__NetBSD__)
#pragma weak pthread_create // Do not create libpthread dependency
#endif
#if defined(_LIBCPP_WIN32API)
#include <windows.h>
#endif
#if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
#pragma comment(lib, "pthread")
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
thread::~thread()
{
if (!__libcpp_thread_isnull(&__t_))
terminate();
}
void
thread::join()
{
int ec = EINVAL;
if (!__libcpp_thread_isnull(&__t_))
{
ec = __libcpp_thread_join(&__t_);
if (ec == 0)
__t_ = _LIBCPP_NULL_THREAD;
}
if (ec)
__throw_system_error(ec, "thread::join failed");
}
void
thread::detach()
{
int ec = EINVAL;
if (!__libcpp_thread_isnull(&__t_))
{
ec = __libcpp_thread_detach(&__t_);
if (ec == 0)
__t_ = _LIBCPP_NULL_THREAD;
}
if (ec)
__throw_system_error(ec, "thread::detach failed");
}
unsigned
thread::hardware_concurrency() noexcept
{
#if defined(_SC_NPROCESSORS_ONLN)
long result = sysconf(_SC_NPROCESSORS_ONLN);
// sysconf returns -1 if the name is invalid, the option does not exist or
// does not have a definite limit.
// if sysconf returns some other negative number, we have no idea
// what is going on. Default to something safe.
if (result < 0)
return 0;
return static_cast<unsigned>(result);
#elif defined(_LIBCPP_WIN32API)
SYSTEM_INFO info;
GetSystemInfo(&info);
return info.dwNumberOfProcessors;
#else // defined(CTL_HW) && defined(HW_NCPU)
// TODO: grovel through /proc or check cpuid on x86 and similar
// instructions on other architectures.
# if defined(_LIBCPP_WARNING)
_LIBCPP_WARNING("hardware_concurrency not yet implemented")
# else
# warning hardware_concurrency not yet implemented
# endif
return 0; // Means not computable [thread.thread.static]
#endif // defined(CTL_HW) && defined(HW_NCPU)
}
namespace this_thread
{
void
sleep_for(const chrono::nanoseconds& ns)
{
if (ns > chrono::nanoseconds::zero())
{
__libcpp_thread_sleep_for(ns);
}
}
} // this_thread
__thread_specific_ptr<__thread_struct>&
__thread_local_data()
{
// Even though __thread_specific_ptr's destructor doesn't actually destroy
// anything (see comments there), we can't call it at all because threads may
// outlive the static variable and calling its destructor means accessing an
// object outside of its lifetime, which is UB.
alignas(__thread_specific_ptr<__thread_struct>) static char __b[sizeof(__thread_specific_ptr<__thread_struct>)];
static __thread_specific_ptr<__thread_struct>* __p = new (__b) __thread_specific_ptr<__thread_struct>();
return *__p;
}
// __thread_struct_imp
template <class T>
class _LIBCPP_HIDDEN __hidden_allocator
{
public:
typedef T value_type;
T* allocate(size_t __n)
{return static_cast<T*>(::operator new(__n * sizeof(T)));}
void deallocate(T* __p, size_t) {::operator delete(static_cast<void*>(__p));}
size_t max_size() const {return size_t(~0) / sizeof(T);}
};
class _LIBCPP_HIDDEN __thread_struct_imp
{
typedef vector<__assoc_sub_state*,
__hidden_allocator<__assoc_sub_state*> > _AsyncStates;
typedef vector<pair<condition_variable*, mutex*>,
__hidden_allocator<pair<condition_variable*, mutex*> > > _Notify;
_AsyncStates async_states_;
_Notify notify_;
__thread_struct_imp(const __thread_struct_imp&);
__thread_struct_imp& operator=(const __thread_struct_imp&);
public:
__thread_struct_imp() {}
~__thread_struct_imp();
void notify_all_at_thread_exit(condition_variable* cv, mutex* m);
void __make_ready_at_thread_exit(__assoc_sub_state* __s);
};
__thread_struct_imp::~__thread_struct_imp()
{
for (_Notify::iterator i = notify_.begin(), e = notify_.end();
i != e; ++i)
{
i->first->notify_all();
i->second->unlock();
}
for (_AsyncStates::iterator i = async_states_.begin(), e = async_states_.end();
i != e; ++i)
{
(*i)->__make_ready();
(*i)->__release_shared();
}
}
void
__thread_struct_imp::notify_all_at_thread_exit(condition_variable* cv, mutex* m)
{
notify_.push_back(pair<condition_variable*, mutex*>(cv, m));
}
void
__thread_struct_imp::__make_ready_at_thread_exit(__assoc_sub_state* __s)
{
async_states_.push_back(__s);
__s->__add_shared();
}
// __thread_struct
__thread_struct::__thread_struct()
: __p_(new __thread_struct_imp)
{
}
__thread_struct::~__thread_struct()
{
delete __p_;
}
void
__thread_struct::notify_all_at_thread_exit(condition_variable* cv, mutex* m)
{
__p_->notify_all_at_thread_exit(cv, m);
}
void
__thread_struct::__make_ready_at_thread_exit(__assoc_sub_state* __s)
{
__p_->__make_ready_at_thread_exit(__s);
}
_LIBCPP_END_NAMESPACE_STD
#endif // !_LIBCPP_HAS_NO_THREADS
|
