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Use SRWLOCK in atomic_load operation on shared_ptr #1200

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Merged
Stephan T. Lavavej (StephanTLavavej) merged 3 commits into from
Aug 18, 2020
Merged

Use SRWLOCK in atomic_load operation on shared_ptr #1200

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918bb10
Fix #370
AlexGuteniev Aug 16, 2020
a063941
clang format
AlexGuteniev Aug 16, 2020
c57e232
Update stl/src/atomic.cpp
StephanTLavavej Aug 16, 2020
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29 changes: 9 additions & 20 deletions stl/src/atomic.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -5,32 +5,21 @@

#include <yvals.h>

#include <intrin.h>
#pragma warning(disable : 4793)
#include <synchapi.h>

namespace {
// MUTEX FOR shared_ptr ATOMIC OPERATIONS
SRWLOCK _Shared_ptr_lock = SRWLOCK_INIT;
} // unnamed namespace

_EXTERN_C

// SPIN LOCK FOR shared_ptr ATOMIC OPERATIONS
volatile long _Shared_ptr_flag;

_CRTIMP2_PURE void __cdecl _Lock_shared_ptr_spin_lock() { // spin until _Shared_ptr_flag successfully set
#ifdef _M_ARM
while (_InterlockedExchange_acq(&_Shared_ptr_flag, 1)) {
__yield();
}
#else // _M_ARM
while (_interlockedbittestandset(&_Shared_ptr_flag, 0)) { // set bit 0
}
#endif // _M_ARM
_CRTIMP2_PURE void __cdecl _Lock_shared_ptr_spin_lock() { // TRANSITION, ABI: "spin_lock" name is outdated
AcquireSRWLockExclusive(&_Shared_ptr_lock);
}

_CRTIMP2_PURE void __cdecl _Unlock_shared_ptr_spin_lock() { // release previously obtained lock
#ifdef _M_ARM
__dmb(_ARM_BARRIER_ISH);
__iso_volatile_store32(reinterpret_cast<volatile int*>(&_Shared_ptr_flag), 0);
#else // _M_ARM
_interlockedbittestandreset(&_Shared_ptr_flag, 0); // reset bit 0
#endif // _M_ARM
ReleaseSRWLockExclusive(&_Shared_ptr_lock);
}

_END_EXTERN_C