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Merged
Stephan T. Lavavej (StephanTLavavej) merged 11 commits into from
Aug 9, 2020
Merged

wait/notify atomic<shared_ptr<T>> (#52, P1644R0) #1136

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98e49db
P1644R0 wait/notify atomic<shared_ptr<T>>, #52
AlexGuteniev Aug 3, 2020
b7f5b15
typos
AlexGuteniev Aug 4, 2020
0d66bf5
test atomic_shared_ptr
AlexGuteniev Aug 4, 2020
707046d
Update tests/std/include/test_atomic_wait.hpp
AlexGuteniev Aug 5, 2020
62c68c9
STL comments
AlexGuteniev Aug 5, 2020
10e9302
Merge branch 'atomic_shared_ptr_wait' of https://github.com/AlexGuten…
AlexGuteniev Aug 5, 2020
682ec98
clang format wants wrong order
AlexGuteniev Aug 5, 2020
1a173d2
_Order
AlexGuteniev Aug 5, 2020
03bae8f
Update stl/inc/memory
AlexGuteniev Aug 5, 2020
d35fe92
this
AlexGuteniev Aug 5, 2020
20d0c63
Merge branch 'atomic_shared_ptr_wait'
AlexGuteniev Aug 5, 2020
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102 changes: 72 additions & 30 deletions stl/inc/memory
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Original file line number Diff line number Diff line change
Expand Up @@ -3116,7 +3116,7 @@ protected:
: _Ptr(_Px), _Repptr(reinterpret_cast<uintptr_t>(_Ref)) {}

_NODISCARD _Ref_count_base* _Lock_and_load() const noexcept {
uintptr_t _Rep = _Repptr.load(memory_order::relaxed);
uintptr_t _Rep = _Repptr.load(memory_order_relaxed);
for (;;) {
switch (_Rep & _Lock_mask) {
case _Not_locked: // Can try to lock now
Expand All @@ -3136,8 +3136,8 @@ protected:
[[fallthrough]];

case _Locked_notify_needed: // "Notify needed" is already set, just wait
_Repptr.wait(_Rep, memory_order::relaxed);
_Rep = _Repptr.load(memory_order::relaxed);
_Repptr.wait(_Rep, memory_order_relaxed);
_Rep = _Repptr.load(memory_order_relaxed);
break;

default: // Unrecognized bit pattern
Expand All @@ -3154,7 +3154,27 @@ protected:
}
}

_Ty* _Ptr = nullptr;
void _Wait(_Ty* _Old, memory_order) const noexcept {
for (;;) {
auto _Rep = _Lock_and_load();
bool _Equal = _Ptr.load(memory_order_relaxed) == _Old;
_Store_and_unlock(_Rep);
if (!_Equal) {
break;
}
__std_atomic_wait_direct(&_Ptr, &_Old, sizeof(_Old), _Atomic_wait_no_timeout);
}
}

void notify_one() noexcept {
_Ptr.notify_one();
}

void notify_all() noexcept {
_Ptr.notify_all();
}

atomic<_Ty*> _Ptr{nullptr};
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mutable atomic<uintptr_t> _Repptr{0};
};

Expand All @@ -3172,19 +3192,21 @@ public:
return false;
}

void store(shared_ptr<_Ty> _Value, const memory_order _Order = memory_order::seq_cst) noexcept {
void store(shared_ptr<_Ty> _Value, const memory_order _Order = memory_order_seq_cst) noexcept {
_Check_store_memory_order(_Order);
const auto _Rep = this->_Lock_and_load();
_STD swap(this->_Ptr, _Value._Ptr);
_Ty* const _Tmp = _Value._Ptr;
_Value._Ptr = this->_Ptr.load(memory_order_relaxed);
this->_Ptr.store(_Tmp, memory_order_relaxed);
this->_Store_and_unlock(_Value._Rep);
_Value._Rep = _Rep;
}

_NODISCARD shared_ptr<_Ty> load(const memory_order _Order = memory_order::seq_cst) const noexcept {
_NODISCARD shared_ptr<_Ty> load(const memory_order _Order = memory_order_seq_cst) const noexcept {
_Check_load_memory_order(_Order);
shared_ptr<_Ty> _Result;
const auto _Rep = this->_Lock_and_load();
_Result._Ptr = this->_Ptr;
_Result._Ptr = this->_Ptr.load(memory_order_relaxed);
_Result._Rep = _Rep;
_Result._Incref();
this->_Store_and_unlock(_Rep);
Expand All @@ -3195,12 +3217,12 @@ public:
return load();
}

shared_ptr<_Ty> exchange(shared_ptr<_Ty> _Value, const memory_order _Order = memory_order::seq_cst) noexcept {
shared_ptr<_Ty> exchange(shared_ptr<_Ty> _Value, const memory_order _Order = memory_order_seq_cst) noexcept {
_Check_memory_order(_Order);
shared_ptr<_Ty> _Result;
_Result._Rep = this->_Lock_and_load();
_Result._Ptr = this->_Ptr;
this->_Ptr = _Value._Ptr;
_Result._Ptr = this->_Ptr.load(memory_order_relaxed);
this->_Ptr.store(_Value._Ptr, memory_order_relaxed);
this->_Store_and_unlock(_Value._Rep);
_Value._Ptr = nullptr; // ownership of _Value ref has been given to this, silence decrement
_Value._Rep = nullptr;
Expand All @@ -3218,22 +3240,24 @@ public:
}

bool compare_exchange_weak(shared_ptr<_Ty>& _Expected, shared_ptr<_Ty> _Desired,
const memory_order _Order = memory_order::seq_cst) noexcept {
const memory_order _Order = memory_order_seq_cst) noexcept {
return compare_exchange_strong(_Expected, _STD move(_Desired), _Order);
}

bool compare_exchange_strong(shared_ptr<_Ty>& _Expected, shared_ptr<_Ty> _Desired,
const memory_order _Order = memory_order::seq_cst) noexcept {
const memory_order _Order = memory_order_seq_cst) noexcept {
_Check_memory_order(_Order);
auto _Rep = this->_Lock_and_load();
if (this->_Ptr == _Expected._Ptr && _Rep == _Expected._Rep) {
_STD swap(this->_Ptr, _Desired._Ptr);
if (this->_Ptr.load(memory_order_relaxed) == _Expected._Ptr && _Rep == _Expected._Rep) {
_Ty* const _Tmp = _Desired._Ptr;
_Desired._Ptr = this->_Ptr.load(memory_order_relaxed);
this->_Ptr.store(_Tmp, memory_order_relaxed);
_STD swap(_Rep, _Desired._Rep);
this->_Store_and_unlock(_Rep);
return true;
}
_Ref_count_base* _Expected_rep = _Expected._Rep;
_Expected._Ptr = this->_Ptr;
_Expected._Ptr = this->_Ptr.load(memory_order_relaxed);
_Expected._Rep = _Rep;
_Expected._Incref();
this->_Store_and_unlock(_Rep);
Expand All @@ -3243,6 +3267,13 @@ public:
return false;
}

void wait(shared_ptr<_Ty> _Old, memory_order _Order = memory_order_seq_cst) const noexcept {
this->_Wait(_Old._Ptr, _Order);
}

using _Base::notify_all;
using _Base::notify_one;
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constexpr atomic() noexcept = default;

atomic(const shared_ptr<_Ty> _Value) noexcept : _Base(_Value._Ptr, _Value._Rep) {
Expand All @@ -3257,7 +3288,7 @@ public:
}

~atomic() {
const auto _Rep = reinterpret_cast<_Ref_count_base*>(this->_Repptr.load(memory_order::relaxed));
const auto _Rep = reinterpret_cast<_Ref_count_base*>(this->_Repptr.load(memory_order_relaxed));
if (_Rep) {
_Rep->_Decref();
}
Expand All @@ -3278,19 +3309,21 @@ public:
return false;
}

void store(weak_ptr<_Ty> _Value, const memory_order _Order = memory_order::seq_cst) noexcept {
void store(weak_ptr<_Ty> _Value, const memory_order _Order = memory_order_seq_cst) noexcept {
_Check_store_memory_order(_Order);
const auto _Rep = this->_Lock_and_load();
_STD swap(this->_Ptr, _Value._Ptr);
_Ty* const _Tmp = _Value._Ptr;
_Value._Ptr = this->_Ptr.load(memory_order_relaxed);
this->_Ptr.store(_Tmp, memory_order_relaxed);
this->_Store_and_unlock(_Value._Rep);
_Value._Rep = _Rep;
}

_NODISCARD weak_ptr<_Ty> load(const memory_order _Order = memory_order::seq_cst) const noexcept {
_NODISCARD weak_ptr<_Ty> load(const memory_order _Order = memory_order_seq_cst) const noexcept {
_Check_load_memory_order(_Order);
weak_ptr<_Ty> _Result;
const auto _Rep = this->_Lock_and_load();
_Result._Ptr = this->_Ptr;
_Result._Ptr = this->_Ptr.load(memory_order_relaxed);
_Result._Rep = _Rep;
_Result._Incwref();
this->_Store_and_unlock(_Rep);
Expand All @@ -3301,12 +3334,12 @@ public:
return load();
}

weak_ptr<_Ty> exchange(weak_ptr<_Ty> _Value, const memory_order _Order = memory_order::seq_cst) noexcept {
weak_ptr<_Ty> exchange(weak_ptr<_Ty> _Value, const memory_order _Order = memory_order_seq_cst) noexcept {
_Check_memory_order(_Order);
weak_ptr<_Ty> _Result;
_Result._Rep = this->_Lock_and_load();
_Result._Ptr = this->_Ptr;
this->_Ptr = _Value._Ptr;
_Result._Ptr = this->_Ptr.load(memory_order_relaxed);
this->_Ptr.store(_Value._Ptr, memory_order_relaxed);
this->_Store_and_unlock(_Value._Rep);
_Value._Ptr = nullptr; // ownership of _Value ref has been given to this, silence decrement
_Value._Rep = nullptr;
Expand All @@ -3324,22 +3357,24 @@ public:
}

bool compare_exchange_weak(
weak_ptr<_Ty>& _Expected, weak_ptr<_Ty> _Desired, const memory_order _Order = memory_order::seq_cst) noexcept {
weak_ptr<_Ty>& _Expected, weak_ptr<_Ty> _Desired, const memory_order _Order = memory_order_seq_cst) noexcept {
return compare_exchange_strong(_Expected, _STD move(_Desired), _Order);
}

bool compare_exchange_strong(
weak_ptr<_Ty>& _Expected, weak_ptr<_Ty> _Desired, const memory_order _Order = memory_order::seq_cst) noexcept {
weak_ptr<_Ty>& _Expected, weak_ptr<_Ty> _Desired, const memory_order _Order = memory_order_seq_cst) noexcept {
_Check_memory_order(_Order);
auto _Rep = this->_Lock_and_load();
if (this->_Ptr == _Expected._Ptr && _Rep == _Expected._Rep) {
_STD swap(this->_Ptr, _Desired._Ptr);
if (this->_Ptr.load(memory_order_relaxed) == _Expected._Ptr && _Rep == _Expected._Rep) {
_Ty* const _Tmp = _Desired._Ptr;
_Desired._Ptr = this->_Ptr.load(memory_order_relaxed);
this->_Ptr.store(_Tmp, memory_order_relaxed);
_STD swap(_Rep, _Desired._Rep);
this->_Store_and_unlock(_Rep);
return true;
}
const auto _Expected_rep = _Expected._Rep;
_Expected._Ptr = this->_Ptr;
_Expected._Ptr = this->_Ptr.load(memory_order_relaxed);
_Expected._Rep = _Rep;
_Expected._Incwref();
this->_Store_and_unlock(_Rep);
Expand All @@ -3349,6 +3384,13 @@ public:
return false;
}

void wait(weak_ptr<_Ty> _Old, memory_order _Order = memory_order_seq_cst) const noexcept {
this->_Wait(_Old._Ptr, _Order);
}

using _Base::notify_all;
using _Base::notify_one;

constexpr atomic() noexcept = default;

atomic(const weak_ptr<_Ty> _Value) noexcept : _Base(_Value._Ptr, _Value._Rep) {
Expand All @@ -3363,7 +3405,7 @@ public:
}

~atomic() {
const auto _Rep = reinterpret_cast<_Ref_count_base*>(this->_Repptr.load(memory_order::relaxed));
const auto _Rep = reinterpret_cast<_Ref_count_base*>(this->_Repptr.load(memory_order_relaxed));
if (_Rep) {
_Rep->_Decwref();
}
Expand Down
5 changes: 5 additions & 0 deletions tests/std/include/test_atomic_wait.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@
#include <assert.h>
#include <atomic>
#include <chrono>
#include <memory>
#include <string.h>
#include <thread>

Expand Down Expand Up @@ -174,6 +175,10 @@ inline void test_atomic_wait() {
test_atomic_wait_func(three_chars{1, 1, 3}, three_chars{1, 2, 3}, waiting_duration);
test_atomic_wait_func(big_char_like{'a'}, big_char_like{'b'}, waiting_duration);

test_atomic_wait_func(std::make_shared<int>('a'), std::make_shared<int>('b'), waiting_duration);
test_atomic_wait_func(
std::weak_ptr{std::make_shared<int>('a')}, std::weak_ptr{std::make_shared<int>('b')}, waiting_duration);

test_notify_all_notifies_all<char>(1, 2, waiting_duration);
test_notify_all_notifies_all<signed char>(1, 2, waiting_duration);
test_notify_all_notifies_all<unsigned char>(1, 2, waiting_duration);
Expand Down