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#ifdef _WIN32
#include "lldb/Host/ProcessRunLock.h"
#include "lldb/Host/windows/windows.h"
namespace lldb_private {
// Windows has slim read-writer lock support on Vista and higher, so we
// will attempt to load the APIs. If they exist, we will use them, and
// if not, we will fall back on critical sections. When we drop support
// for XP, we can stop lazy-loading these APIs and just use them directly.
#if defined(__MINGW32__)
// Taken from WinNT.h
typedef struct _RTL_SRWLOCK {
PVOID Ptr;
} RTL_SRWLOCK, *PRTL_SRWLOCK;
// Taken from WinBase.h
typedef RTL_SRWLOCK SRWLOCK, *PSRWLOCK;
#endif
typedef struct Win32RWLOCK
{
long int readlockcount;
HANDLE writable;
CRITICAL_SECTION writelock;
long int writelocked;
} Win32RWLOCK;
typedef Win32RWLOCK* PWin32RWLOCK;
static VOID (WINAPI *fpInitializeSRWLock)(PSRWLOCK lock) = NULL;
static VOID (WINAPI *fpAcquireSRWLockExclusive)(PSRWLOCK lock) = NULL;
static VOID (WINAPI *fpAcquireSRWLockShared)(PSRWLOCK lock) = NULL;
static VOID (WINAPI *fpReleaseSRWLockExclusive)(PSRWLOCK lock) = NULL;
static VOID (WINAPI *fpReleaseSRWLockShared)(PSRWLOCK lock) = NULL;
static BOOL (WINAPI *fpTryAcquireSRWLockExclusive)(PSRWLOCK lock) = NULL;
static BOOL (WINAPI *fpTryAcquireSRWLockShared)(PSRWLOCK lock) = NULL;
static bool sHasSRW = false;
static bool loadSRW()
{
static bool sChecked = false;
if (!sChecked)
{
sChecked = true;
return false;
HMODULE hLib = ::LoadLibrary(TEXT("Kernel32"));
if (hLib)
{
fpInitializeSRWLock =
(VOID (WINAPI *)(PSRWLOCK))::GetProcAddress(hLib,
"InitializeSRWLock");
fpAcquireSRWLockExclusive =
(VOID (WINAPI *)(PSRWLOCK))::GetProcAddress(hLib,
"AcquireSRWLockExclusive");
fpAcquireSRWLockShared =
(VOID (WINAPI *)(PSRWLOCK))::GetProcAddress(hLib,
"AcquireSRWLockShared");
fpReleaseSRWLockExclusive =
(VOID (WINAPI *)(PSRWLOCK))::GetProcAddress(hLib,
"ReleaseSRWLockExclusive");
fpReleaseSRWLockShared =
(VOID (WINAPI *)(PSRWLOCK))::GetProcAddress(hLib,
"ReleaseSRWLockShared");
fpTryAcquireSRWLockExclusive =
(BOOL (WINAPI *)(PSRWLOCK))::GetProcAddress(hLib,
"TryAcquireSRWLockExclusive");
fpTryAcquireSRWLockShared =
(BOOL (WINAPI *)(PSRWLOCK))::GetProcAddress(hLib,
"TryAcquireSRWLockShared");
::FreeLibrary(hLib);
if (fpInitializeSRWLock != NULL) {
sHasSRW = true;
}
}
}
return sHasSRW;
}
ProcessRunLock::ProcessRunLock ()
: m_running(false)
{
if (loadSRW())
{
m_rwlock = calloc(1, sizeof(SRWLOCK));
fpInitializeSRWLock(static_cast<PSRWLOCK>(m_rwlock));
}
else
{
m_rwlock = calloc(1, sizeof(Win32RWLOCK));
static_cast<PWin32RWLOCK>(m_rwlock)->readlockcount = 0;
static_cast<PWin32RWLOCK>(m_rwlock)->writable = CreateEvent(NULL, true, true, NULL);
InitializeCriticalSection(&static_cast<PWin32RWLOCK>(m_rwlock)->writelock);
}
}
ProcessRunLock::~ProcessRunLock ()
{
if (!sHasSRW)
{
CloseHandle(static_cast<PWin32RWLOCK>(m_rwlock)->writable);
DeleteCriticalSection(&static_cast<PWin32RWLOCK>(m_rwlock)->writelock);
}
free(m_rwlock);
}
bool ReadLock (lldb::rwlock_t rwlock)
{
if (sHasSRW)
{
fpAcquireSRWLockShared(static_cast<PSRWLOCK>(rwlock));
return true;
}
else
{
EnterCriticalSection(&static_cast<PWin32RWLOCK>(rwlock)->writelock);
InterlockedIncrement(&static_cast<PWin32RWLOCK>(rwlock)->readlockcount);
ResetEvent(static_cast<PWin32RWLOCK>(rwlock)->writable);
LeaveCriticalSection(&static_cast<PWin32RWLOCK>(rwlock)->writelock);
return true;
}
}
bool ProcessRunLock::ReadTryLock ()
{
ReadLock(m_rwlock);
if (m_running == false)
return true;
ReadUnlock();
return false;
}
bool ProcessRunLock::ReadUnlock ()
{
if (sHasSRW)
{
fpReleaseSRWLockShared(static_cast<PSRWLOCK>(m_rwlock));
return true;
}
else
{
unsigned long int value = InterlockedDecrement(&static_cast<PWin32RWLOCK>(m_rwlock)->readlockcount);
assert(((int)value) >= 0);
if (value == 0)
SetEvent(static_cast<PWin32RWLOCK>(m_rwlock)->writable);
return true;
}
}
bool WriteLock(lldb::rwlock_t rwlock)
{
if (sHasSRW)
{
fpAcquireSRWLockExclusive(static_cast<PSRWLOCK>(rwlock));
return true;
}
else
{
EnterCriticalSection(&static_cast<PWin32RWLOCK>(rwlock)->writelock);
WaitForSingleObject(static_cast<PWin32RWLOCK>(rwlock)->writable, INFINITE);
int res = InterlockedExchange(&static_cast<PWin32RWLOCK>(rwlock)->writelocked, 1);
assert(res == 0);
return true;
}
}
bool WriteTryLock(lldb::rwlock_t rwlock)
{
if (sHasSRW)
{
return fpTryAcquireSRWLockExclusive(static_cast<PSRWLOCK>(rwlock)) != 0;
}
else
{
if (TryEnterCriticalSection(&static_cast<PWin32RWLOCK>(rwlock)->writelock)) {
if (WaitForSingleObject(static_cast<PWin32RWLOCK>(rwlock)->writable, 0)) {
LeaveCriticalSection(&static_cast<PWin32RWLOCK>(rwlock)->writelock);
return false;
}
int res = InterlockedExchange(&static_cast<PWin32RWLOCK>(rwlock)->writelocked, 1);
assert(res == 0);
return true;
}
return false;
}
}
bool WriteUnlock(lldb::rwlock_t rwlock)
{
if (sHasSRW)
{
fpReleaseSRWLockExclusive(static_cast<PSRWLOCK>(rwlock));
return true;
}
else
{
int res = InterlockedExchange(&static_cast<PWin32RWLOCK>(rwlock)->writelocked, 0);
if (res == 1) {
LeaveCriticalSection(&static_cast<PWin32RWLOCK>(rwlock)->writelock);
return true;
}
return false;
}
}
bool ProcessRunLock::SetRunning ()
{
WriteLock(m_rwlock);
m_running = true;
WriteUnlock(m_rwlock);
return true;
}
bool ProcessRunLock::TrySetRunning ()
{
if (WriteTryLock(m_rwlock))
{
bool r = !m_running;
m_running = true;
WriteUnlock(m_rwlock);
return r;
}
return false;
}
bool ProcessRunLock::SetStopped ()
{
WriteLock(m_rwlock);
m_running = false;
WriteUnlock(m_rwlock);
return true;
}
}
#endif
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