1218885Sdim//= llvm/Support/Win32/Mutex.inc - Win32 Reader/Writer Mutual Exclusion Lock =// 2218885Sdim// 3218885Sdim// The LLVM Compiler Infrastructure 4218885Sdim// 5218885Sdim// This file is distributed under the University of Illinois Open Source 6218885Sdim// License. See LICENSE.TXT for details. 7218885Sdim// 8218885Sdim//===----------------------------------------------------------------------===// 9218885Sdim// 10218885Sdim// This file implements the Win32 specific (non-pthread) RWMutex class. 11218885Sdim// 12218885Sdim//===----------------------------------------------------------------------===// 13218885Sdim 14218885Sdim//===----------------------------------------------------------------------===// 15218885Sdim//=== WARNING: Implementation here must contain only generic Win32 code that 16218885Sdim//=== is guaranteed to work on *all* Win32 variants. 17218885Sdim//===----------------------------------------------------------------------===// 18218885Sdim 19218885Sdim#include "Windows.h" 20218885Sdim 21218885Sdimnamespace llvm { 22218885Sdimusing namespace sys; 23218885Sdim 24226633Sdim// Windows has slim read-writer lock support on Vista and higher, so we 25226633Sdim// will attempt to load the APIs. If they exist, we will use them, and 26226633Sdim// if not, we will fall back on critical sections. When we drop support 27226633Sdim// for XP, we can stop lazy-loading these APIs and just use them directly. 28226633Sdim#if defined(__MINGW32__) 29226633Sdim // Taken from WinNT.h 30226633Sdim typedef struct _RTL_SRWLOCK { 31226633Sdim PVOID Ptr; 32226633Sdim } RTL_SRWLOCK, *PRTL_SRWLOCK; 33226633Sdim 34226633Sdim // Taken from WinBase.h 35226633Sdim typedef RTL_SRWLOCK SRWLOCK, *PSRWLOCK; 36226633Sdim#endif 37226633Sdim 38226633Sdimstatic VOID (WINAPI *fpInitializeSRWLock)(PSRWLOCK lock) = NULL; 39226633Sdimstatic VOID (WINAPI *fpAcquireSRWLockExclusive)(PSRWLOCK lock) = NULL; 40226633Sdimstatic VOID (WINAPI *fpAcquireSRWLockShared)(PSRWLOCK lock) = NULL; 41226633Sdimstatic VOID (WINAPI *fpReleaseSRWLockExclusive)(PSRWLOCK lock) = NULL; 42226633Sdimstatic VOID (WINAPI *fpReleaseSRWLockShared)(PSRWLOCK lock) = NULL; 43226633Sdim 44226633Sdimstatic bool sHasSRW = false; 45226633Sdim 46226633Sdimstatic bool loadSRW() { 47226633Sdim static bool sChecked = false; 48226633Sdim if (!sChecked) { 49226633Sdim sChecked = true; 50226633Sdim 51263508Sdim if (HMODULE hLib = ::GetModuleHandleW(L"Kernel32.dll")) { 52226633Sdim fpInitializeSRWLock = 53226633Sdim (VOID (WINAPI *)(PSRWLOCK))::GetProcAddress(hLib, 54226633Sdim "InitializeSRWLock"); 55226633Sdim fpAcquireSRWLockExclusive = 56226633Sdim (VOID (WINAPI *)(PSRWLOCK))::GetProcAddress(hLib, 57226633Sdim "AcquireSRWLockExclusive"); 58226633Sdim fpAcquireSRWLockShared = 59226633Sdim (VOID (WINAPI *)(PSRWLOCK))::GetProcAddress(hLib, 60226633Sdim "AcquireSRWLockShared"); 61226633Sdim fpReleaseSRWLockExclusive = 62226633Sdim (VOID (WINAPI *)(PSRWLOCK))::GetProcAddress(hLib, 63226633Sdim "ReleaseSRWLockExclusive"); 64226633Sdim fpReleaseSRWLockShared = 65226633Sdim (VOID (WINAPI *)(PSRWLOCK))::GetProcAddress(hLib, 66226633Sdim "ReleaseSRWLockShared"); 67226633Sdim 68239462Sdim if (fpInitializeSRWLock != NULL) { 69239462Sdim sHasSRW = true; 70239462Sdim } 71226633Sdim } 72226633Sdim } 73226633Sdim return sHasSRW; 74226633Sdim} 75226633Sdim 76218885SdimRWMutexImpl::RWMutexImpl() { 77226633Sdim if (loadSRW()) { 78226633Sdim data_ = calloc(1, sizeof(SRWLOCK)); 79226633Sdim fpInitializeSRWLock(static_cast<PSRWLOCK>(data_)); 80226633Sdim } else { 81226633Sdim data_ = calloc(1, sizeof(CRITICAL_SECTION)); 82226633Sdim InitializeCriticalSection(static_cast<LPCRITICAL_SECTION>(data_)); 83226633Sdim } 84218885Sdim} 85218885Sdim 86218885SdimRWMutexImpl::~RWMutexImpl() { 87226633Sdim if (sHasSRW) { 88226633Sdim // Nothing to do in the case of slim reader/writers 89226633Sdim } else { 90226633Sdim DeleteCriticalSection(static_cast<LPCRITICAL_SECTION>(data_)); 91226633Sdim free(data_); 92226633Sdim } 93218885Sdim} 94218885Sdim 95218885Sdimbool RWMutexImpl::reader_acquire() { 96226633Sdim if (sHasSRW) { 97226633Sdim fpAcquireSRWLockShared(static_cast<PSRWLOCK>(data_)); 98226633Sdim } else { 99226633Sdim EnterCriticalSection(static_cast<LPCRITICAL_SECTION>(data_)); 100226633Sdim } 101218885Sdim return true; 102218885Sdim} 103218885Sdim 104218885Sdimbool RWMutexImpl::reader_release() { 105226633Sdim if (sHasSRW) { 106226633Sdim fpReleaseSRWLockShared(static_cast<PSRWLOCK>(data_)); 107226633Sdim } else { 108226633Sdim LeaveCriticalSection(static_cast<LPCRITICAL_SECTION>(data_)); 109226633Sdim } 110218885Sdim return true; 111218885Sdim} 112218885Sdim 113218885Sdimbool RWMutexImpl::writer_acquire() { 114226633Sdim if (sHasSRW) { 115226633Sdim fpAcquireSRWLockExclusive(static_cast<PSRWLOCK>(data_)); 116226633Sdim } else { 117226633Sdim EnterCriticalSection(static_cast<LPCRITICAL_SECTION>(data_)); 118226633Sdim } 119218885Sdim return true; 120218885Sdim} 121218885Sdim 122218885Sdimbool RWMutexImpl::writer_release() { 123226633Sdim if (sHasSRW) { 124226633Sdim fpReleaseSRWLockExclusive(static_cast<PSRWLOCK>(data_)); 125226633Sdim } else { 126226633Sdim LeaveCriticalSection(static_cast<LPCRITICAL_SECTION>(data_)); 127226633Sdim } 128218885Sdim return true; 129218885Sdim} 130218885Sdim 131218885Sdim 132218885Sdim} 133