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llvm-project/libcxx/include/mutex
Louis Dionne c0cde79e9e [libc++] Remove C++03 extensions for std::allocator_arg & friends 
As explained in the release note, libc++ used to provide various
global variables as an extension in C++03 mode. Unfortunately, that
made our definition non-conforming in all standard modes. This was
never a big problem until recently, since we are trying to support
C++20 Modules in libc++, and that requires cleaning up the definition
of these variables.

This change is the first in a series of changes to achieve our end goal.
This patch removes the ability for users to rely on the (incorrect)
definition of those global variables inside the shared library. The
plan is to then remove those definitions from the shared library
(which is an ABI break but I don't think it will have impact), and
finally to make our definition of those variables conforming in all
standard modes.

Differential Revision: https://reviews.llvm.org/D145422
2023-03-19 10:14:32 -04:00

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// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP_MUTEX
#define _LIBCPP_MUTEX
/*
mutex synopsis
namespace std
{
class mutex
{
public:
constexpr mutex() noexcept;
~mutex();
mutex(const mutex&) = delete;
mutex& operator=(const mutex&) = delete;
void lock();
bool try_lock();
void unlock();
typedef pthread_mutex_t* native_handle_type;
native_handle_type native_handle();
};
class recursive_mutex
{
public:
recursive_mutex();
~recursive_mutex();
recursive_mutex(const recursive_mutex&) = delete;
recursive_mutex& operator=(const recursive_mutex&) = delete;
void lock();
bool try_lock() noexcept;
void unlock();
typedef pthread_mutex_t* native_handle_type;
native_handle_type native_handle();
};
class timed_mutex
{
public:
timed_mutex();
~timed_mutex();
timed_mutex(const timed_mutex&) = delete;
timed_mutex& operator=(const timed_mutex&) = delete;
void lock();
bool try_lock();
template <class Rep, class Period>
bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
template <class Clock, class Duration>
bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
void unlock();
};
class recursive_timed_mutex
{
public:
recursive_timed_mutex();
~recursive_timed_mutex();
recursive_timed_mutex(const recursive_timed_mutex&) = delete;
recursive_timed_mutex& operator=(const recursive_timed_mutex&) = delete;
void lock();
bool try_lock() noexcept;
template <class Rep, class Period>
bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
template <class Clock, class Duration>
bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
void unlock();
};
struct defer_lock_t { explicit defer_lock_t() = default; };
struct try_to_lock_t { explicit try_to_lock_t() = default; };
struct adopt_lock_t { explicit adopt_lock_t() = default; };
inline constexpr defer_lock_t defer_lock{};
inline constexpr try_to_lock_t try_to_lock{};
inline constexpr adopt_lock_t adopt_lock{};
template <class Mutex>
class lock_guard
{
public:
typedef Mutex mutex_type;
explicit lock_guard(mutex_type& m);
lock_guard(mutex_type& m, adopt_lock_t);
~lock_guard();
lock_guard(lock_guard const&) = delete;
lock_guard& operator=(lock_guard const&) = delete;
};
template <class... MutexTypes>
class scoped_lock // C++17
{
public:
using mutex_type = Mutex; // Only if sizeof...(MutexTypes) == 1
explicit scoped_lock(MutexTypes&... m);
scoped_lock(adopt_lock_t, MutexTypes&... m);
~scoped_lock();
scoped_lock(scoped_lock const&) = delete;
scoped_lock& operator=(scoped_lock const&) = delete;
private:
tuple<MutexTypes&...> pm; // exposition only
};
template <class Mutex>
class unique_lock
{
public:
typedef Mutex mutex_type;
unique_lock() noexcept;
explicit unique_lock(mutex_type& m);
unique_lock(mutex_type& m, defer_lock_t) noexcept;
unique_lock(mutex_type& m, try_to_lock_t);
unique_lock(mutex_type& m, adopt_lock_t);
template <class Clock, class Duration>
unique_lock(mutex_type& m, const chrono::time_point<Clock, Duration>& abs_time);
template <class Rep, class Period>
unique_lock(mutex_type& m, const chrono::duration<Rep, Period>& rel_time);
~unique_lock();
unique_lock(unique_lock const&) = delete;
unique_lock& operator=(unique_lock const&) = delete;
unique_lock(unique_lock&& u) noexcept;
unique_lock& operator=(unique_lock&& u) noexcept;
void lock();
bool try_lock();
template <class Rep, class Period>
bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
template <class Clock, class Duration>
bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
void unlock();
void swap(unique_lock& u) noexcept;
mutex_type* release() noexcept;
bool owns_lock() const noexcept;
explicit operator bool () const noexcept;
mutex_type* mutex() const noexcept;
};
template <class Mutex>
void swap(unique_lock<Mutex>& x, unique_lock<Mutex>& y) noexcept;
template <class L1, class L2, class... L3>
int try_lock(L1&, L2&, L3&...);
template <class L1, class L2, class... L3>
void lock(L1&, L2&, L3&...);
struct once_flag
{
constexpr once_flag() noexcept;
once_flag(const once_flag&) = delete;
once_flag& operator=(const once_flag&) = delete;
};
template<class Callable, class ...Args>
void call_once(once_flag& flag, Callable&& func, Args&&... args);
} // std
*/
#include <__assert> // all public C++ headers provide the assertion handler
#include <__config>
#include <__memory/shared_ptr.h>
#include <__mutex_base>
#include <__threading_support>
#include <__utility/forward.h>
#include <cstdint>
#ifndef _LIBCPP_CXX03_LANG
# include <tuple>
#endif
#include <version>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
#ifndef _LIBCPP_HAS_NO_THREADS
class _LIBCPP_TYPE_VIS recursive_mutex
{
__libcpp_recursive_mutex_t __m_;
public:
recursive_mutex();
~recursive_mutex();
recursive_mutex(const recursive_mutex&) = delete;
recursive_mutex& operator=(const recursive_mutex&) = delete;
void lock();
bool try_lock() _NOEXCEPT;
void unlock() _NOEXCEPT;
typedef __libcpp_recursive_mutex_t* native_handle_type;
_LIBCPP_INLINE_VISIBILITY
native_handle_type native_handle() {return &__m_;}
};
class _LIBCPP_TYPE_VIS timed_mutex
{
mutex __m_;
condition_variable __cv_;
bool __locked_;
public:
timed_mutex();
~timed_mutex();
timed_mutex(const timed_mutex&) = delete;
timed_mutex& operator=(const timed_mutex&) = delete;
public:
void lock();
bool try_lock() _NOEXCEPT;
template <class _Rep, class _Period>
_LIBCPP_INLINE_VISIBILITY
bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
{return try_lock_until(chrono::steady_clock::now() + __d);}
template <class _Clock, class _Duration>
_LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
void unlock() _NOEXCEPT;
};
template <class _Clock, class _Duration>
bool
timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
{
using namespace chrono;
unique_lock<mutex> __lk(__m_);
bool __no_timeout = _Clock::now() < __t;
while (__no_timeout && __locked_)
__no_timeout = __cv_.wait_until(__lk, __t) == cv_status::no_timeout;
if (!__locked_)
{
__locked_ = true;
return true;
}
return false;
}
class _LIBCPP_TYPE_VIS recursive_timed_mutex
{
mutex __m_;
condition_variable __cv_;
size_t __count_;
__thread_id __id_;
public:
recursive_timed_mutex();
~recursive_timed_mutex();
recursive_timed_mutex(const recursive_timed_mutex&) = delete;
recursive_timed_mutex& operator=(const recursive_timed_mutex&) = delete;
void lock();
bool try_lock() _NOEXCEPT;
template <class _Rep, class _Period>
_LIBCPP_INLINE_VISIBILITY
bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
{return try_lock_until(chrono::steady_clock::now() + __d);}
template <class _Clock, class _Duration>
_LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
void unlock() _NOEXCEPT;
};
template <class _Clock, class _Duration>
bool
recursive_timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
{
using namespace chrono;
__thread_id __id = this_thread::get_id();
unique_lock<mutex> __lk(__m_);
if (__id == __id_)
{
if (__count_ == numeric_limits<size_t>::max())
return false;
++__count_;
return true;
}
bool __no_timeout = _Clock::now() < __t;
while (__no_timeout && __count_ != 0)
__no_timeout = __cv_.wait_until(__lk, __t) == cv_status::no_timeout;
if (__count_ == 0)
{
__count_ = 1;
__id_ = __id;
return true;
}
return false;
}
template <class _L0, class _L1>
_LIBCPP_HIDE_FROM_ABI int
try_lock(_L0& __l0, _L1& __l1)
{
unique_lock<_L0> __u0(__l0, try_to_lock_t());
if (__u0.owns_lock())
{
if (__l1.try_lock())
{
__u0.release();
return -1;
}
else
return 1;
}
return 0;
}
#ifndef _LIBCPP_CXX03_LANG
template <class _L0, class _L1, class _L2, class... _L3>
_LIBCPP_HIDE_FROM_ABI int
try_lock(_L0& __l0, _L1& __l1, _L2& __l2, _L3&... __l3)
{
int __r = 0;
unique_lock<_L0> __u0(__l0, try_to_lock);
if (__u0.owns_lock())
{
__r = std::try_lock(__l1, __l2, __l3...);
if (__r == -1)
__u0.release();
else
++__r;
}
return __r;
}
#endif // _LIBCPP_CXX03_LANG
template <class _L0, class _L1>
_LIBCPP_HIDE_FROM_ABI void
lock(_L0& __l0, _L1& __l1)
{
while (true)
{
{
unique_lock<_L0> __u0(__l0);
if (__l1.try_lock())
{
__u0.release();
break;
}
}
__libcpp_thread_yield();
{
unique_lock<_L1> __u1(__l1);
if (__l0.try_lock())
{
__u1.release();
break;
}
}
__libcpp_thread_yield();
}
}
#ifndef _LIBCPP_CXX03_LANG
template <class _L0, class _L1, class _L2, class ..._L3>
void
__lock_first(int __i, _L0& __l0, _L1& __l1, _L2& __l2, _L3& ...__l3)
{
while (true)
{
switch (__i)
{
case 0:
{
unique_lock<_L0> __u0(__l0);
__i = std::try_lock(__l1, __l2, __l3...);
if (__i == -1)
{
__u0.release();
return;
}
}
++__i;
__libcpp_thread_yield();
break;
case 1:
{
unique_lock<_L1> __u1(__l1);
__i = std::try_lock(__l2, __l3..., __l0);
if (__i == -1)
{
__u1.release();
return;
}
}
if (__i == sizeof...(_L3) + 1)
__i = 0;
else
__i += 2;
__libcpp_thread_yield();
break;
default:
std::__lock_first(__i - 2, __l2, __l3..., __l0, __l1);
return;
}
}
}
template <class _L0, class _L1, class _L2, class ..._L3>
inline _LIBCPP_INLINE_VISIBILITY
void
lock(_L0& __l0, _L1& __l1, _L2& __l2, _L3& ...__l3)
{
std::__lock_first(0, __l0, __l1, __l2, __l3...);
}
template <class _L0>
inline _LIBCPP_INLINE_VISIBILITY
void __unlock(_L0& __l0) {
__l0.unlock();
}
template <class _L0, class _L1>
inline _LIBCPP_INLINE_VISIBILITY
void __unlock(_L0& __l0, _L1& __l1) {
__l0.unlock();
__l1.unlock();
}
template <class _L0, class _L1, class _L2, class ..._L3>
inline _LIBCPP_INLINE_VISIBILITY
void __unlock(_L0& __l0, _L1& __l1, _L2& __l2, _L3&... __l3) {
__l0.unlock();
__l1.unlock();
_VSTD::__unlock(__l2, __l3...);
}
#endif // _LIBCPP_CXX03_LANG
#if _LIBCPP_STD_VER >= 17
template <class ..._Mutexes>
class _LIBCPP_TEMPLATE_VIS scoped_lock;
template <>
class _LIBCPP_TEMPLATE_VIS scoped_lock<> {
public:
explicit scoped_lock() {}
~scoped_lock() = default;
_LIBCPP_INLINE_VISIBILITY
explicit scoped_lock(adopt_lock_t) {}
scoped_lock(scoped_lock const&) = delete;
scoped_lock& operator=(scoped_lock const&) = delete;
};
template <class _Mutex>
class _LIBCPP_TEMPLATE_VIS _LIBCPP_THREAD_SAFETY_ANNOTATION(scoped_lockable) scoped_lock<_Mutex> {
public:
typedef _Mutex mutex_type;
private:
mutex_type& __m_;
public:
explicit scoped_lock(mutex_type & __m) _LIBCPP_THREAD_SAFETY_ANNOTATION(acquire_capability(__m))
: __m_(__m) {__m_.lock();}
~scoped_lock() _LIBCPP_THREAD_SAFETY_ANNOTATION(release_capability()) {__m_.unlock();}
_LIBCPP_INLINE_VISIBILITY
explicit scoped_lock(adopt_lock_t, mutex_type& __m) _LIBCPP_THREAD_SAFETY_ANNOTATION(requires_capability(__m))
: __m_(__m) {}
scoped_lock(scoped_lock const&) = delete;
scoped_lock& operator=(scoped_lock const&) = delete;
};
template <class ..._MArgs>
class _LIBCPP_TEMPLATE_VIS scoped_lock
{
static_assert(sizeof...(_MArgs) > 1, "At least 2 lock types required");
typedef tuple<_MArgs&...> _MutexTuple;
public:
_LIBCPP_INLINE_VISIBILITY
explicit scoped_lock(_MArgs&... __margs)
: __t_(__margs...)
{
_VSTD::lock(__margs...);
}
_LIBCPP_INLINE_VISIBILITY
scoped_lock(adopt_lock_t, _MArgs&... __margs)
: __t_(__margs...)
{
}
_LIBCPP_INLINE_VISIBILITY
~scoped_lock() {
typedef typename __make_tuple_indices<sizeof...(_MArgs)>::type _Indices;
__unlock_unpack(_Indices{}, __t_);
}
scoped_lock(scoped_lock const&) = delete;
scoped_lock& operator=(scoped_lock const&) = delete;
private:
template <size_t ..._Indx>
_LIBCPP_INLINE_VISIBILITY
static void __unlock_unpack(__tuple_indices<_Indx...>, _MutexTuple& __mt) {
_VSTD::__unlock(_VSTD::get<_Indx>(__mt)...);
}
_MutexTuple __t_;
};
_LIBCPP_CTAD_SUPPORTED_FOR_TYPE(scoped_lock);
#endif // _LIBCPP_STD_VER >= 17
#endif // !_LIBCPP_HAS_NO_THREADS
struct _LIBCPP_TEMPLATE_VIS once_flag;
#ifndef _LIBCPP_CXX03_LANG
template<class _Callable, class... _Args>
_LIBCPP_INLINE_VISIBILITY
void call_once(once_flag&, _Callable&&, _Args&&...);
#else // _LIBCPP_CXX03_LANG
template<class _Callable>
_LIBCPP_INLINE_VISIBILITY
void call_once(once_flag&, _Callable&);
template<class _Callable>
_LIBCPP_INLINE_VISIBILITY
void call_once(once_flag&, const _Callable&);
#endif // _LIBCPP_CXX03_LANG
struct _LIBCPP_TEMPLATE_VIS once_flag
{
_LIBCPP_INLINE_VISIBILITY
_LIBCPP_CONSTEXPR
once_flag() _NOEXCEPT : __state_(0) {}
once_flag(const once_flag&) = delete;
once_flag& operator=(const once_flag&) = delete;
#if defined(_LIBCPP_ABI_MICROSOFT)
typedef uintptr_t _State_type;
#else
typedef unsigned long _State_type;
#endif
private:
_State_type __state_;
#ifndef _LIBCPP_CXX03_LANG
template<class _Callable, class... _Args>
friend
void call_once(once_flag&, _Callable&&, _Args&&...);
#else // _LIBCPP_CXX03_LANG
template<class _Callable>
friend
void call_once(once_flag&, _Callable&);
template<class _Callable>
friend
void call_once(once_flag&, const _Callable&);
#endif // _LIBCPP_CXX03_LANG
};
#ifndef _LIBCPP_CXX03_LANG
template <class _Fp>
class __call_once_param
{
_Fp& __f_;
public:
_LIBCPP_INLINE_VISIBILITY
explicit __call_once_param(_Fp& __f) : __f_(__f) {}
_LIBCPP_INLINE_VISIBILITY
void operator()()
{
typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 1>::type _Index;
__execute(_Index());
}
private:
template <size_t ..._Indices>
_LIBCPP_INLINE_VISIBILITY
void __execute(__tuple_indices<_Indices...>)
{
_VSTD::__invoke(_VSTD::get<0>(_VSTD::move(__f_)), _VSTD::get<_Indices>(_VSTD::move(__f_))...);
}
};
#else
template <class _Fp>
class __call_once_param
{
_Fp& __f_;
public:
_LIBCPP_INLINE_VISIBILITY
explicit __call_once_param(_Fp& __f) : __f_(__f) {}
_LIBCPP_INLINE_VISIBILITY
void operator()()
{
__f_();
}
};
#endif
template <class _Fp>
void _LIBCPP_INLINE_VISIBILITY
__call_once_proxy(void* __vp)
{
__call_once_param<_Fp>* __p = static_cast<__call_once_param<_Fp>*>(__vp);
(*__p)();
}
_LIBCPP_FUNC_VIS void __call_once(volatile once_flag::_State_type&, void*,
void (*)(void*));
#ifndef _LIBCPP_CXX03_LANG
template<class _Callable, class... _Args>
inline _LIBCPP_INLINE_VISIBILITY
void
call_once(once_flag& __flag, _Callable&& __func, _Args&&... __args)
{
if (__libcpp_acquire_load(&__flag.__state_) != ~once_flag::_State_type(0))
{
typedef tuple<_Callable&&, _Args&&...> _Gp;
_Gp __f(_VSTD::forward<_Callable>(__func), _VSTD::forward<_Args>(__args)...);
__call_once_param<_Gp> __p(__f);
std::__call_once(__flag.__state_, &__p, &__call_once_proxy<_Gp>);
}
}
#else // _LIBCPP_CXX03_LANG
template<class _Callable>
inline _LIBCPP_INLINE_VISIBILITY
void
call_once(once_flag& __flag, _Callable& __func)
{
if (__libcpp_acquire_load(&__flag.__state_) != ~once_flag::_State_type(0))
{
__call_once_param<_Callable> __p(__func);
std::__call_once(__flag.__state_, &__p, &__call_once_proxy<_Callable>);
}
}
template<class _Callable>
inline _LIBCPP_INLINE_VISIBILITY
void
call_once(once_flag& __flag, const _Callable& __func)
{
if (__libcpp_acquire_load(&__flag.__state_) != ~once_flag::_State_type(0))
{
__call_once_param<const _Callable> __p(__func);
std::__call_once(__flag.__state_, &__p, &__call_once_proxy<const _Callable>);
}
}
#endif // _LIBCPP_CXX03_LANG
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
# include <atomic>
# include <concepts>
# include <ctime>
# include <functional>
# include <type_traits>
#endif
#endif // _LIBCPP_MUTEX
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