1 //===- Mutex.cpp - Mutual Exclusion Lock ------------------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file implements the llvm::sys::Mutex class. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/Config/config.h" 15 #include "llvm/Support/Mutex.h" 16 17 //===----------------------------------------------------------------------===// 18 //=== WARNING: Implementation here must contain only TRULY operating system 19 //=== independent code. 20 //===----------------------------------------------------------------------===// 21 22 #if !defined(LLVM_ENABLE_THREADS) || LLVM_ENABLE_THREADS == 0 23 // Define all methods as no-ops if threading is explicitly disabled 24 namespace llvm { 25 using namespace sys; 26 MutexImpl::MutexImpl( bool recursive) { } 27 MutexImpl::~MutexImpl() { } 28 bool MutexImpl::acquire() { return true; } 29 bool MutexImpl::release() { return true; } 30 bool MutexImpl::tryacquire() { return true; } 31 } 32 #else 33 34 #if defined(HAVE_PTHREAD_H) && defined(HAVE_PTHREAD_MUTEX_LOCK) 35 36 #include <cassert> 37 #include <pthread.h> 38 #include <stdlib.h> 39 40 namespace llvm { 41 using namespace sys; 42 43 // Construct a Mutex using pthread calls 44 MutexImpl::MutexImpl( bool recursive) 45 : data_(nullptr) 46 { 47 // Declare the pthread_mutex data structures 48 pthread_mutex_t* mutex = 49 static_cast<pthread_mutex_t*>(malloc(sizeof(pthread_mutex_t))); 50 pthread_mutexattr_t attr; 51 52 // Initialize the mutex attributes 53 int errorcode = pthread_mutexattr_init(&attr); 54 assert(errorcode == 0); (void)errorcode; 55 56 // Initialize the mutex as a recursive mutex, if requested, or normal 57 // otherwise. 58 int kind = ( recursive ? PTHREAD_MUTEX_RECURSIVE : PTHREAD_MUTEX_NORMAL ); 59 errorcode = pthread_mutexattr_settype(&attr, kind); 60 assert(errorcode == 0); 61 62 // Initialize the mutex 63 errorcode = pthread_mutex_init(mutex, &attr); 64 assert(errorcode == 0); 65 66 // Destroy the attributes 67 errorcode = pthread_mutexattr_destroy(&attr); 68 assert(errorcode == 0); 69 70 // Assign the data member 71 data_ = mutex; 72 } 73 74 // Destruct a Mutex 75 MutexImpl::~MutexImpl() 76 { 77 pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_); 78 assert(mutex != nullptr); 79 pthread_mutex_destroy(mutex); 80 free(mutex); 81 } 82 83 bool 84 MutexImpl::acquire() 85 { 86 pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_); 87 assert(mutex != nullptr); 88 89 int errorcode = pthread_mutex_lock(mutex); 90 return errorcode == 0; 91 } 92 93 bool 94 MutexImpl::release() 95 { 96 pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_); 97 assert(mutex != nullptr); 98 99 int errorcode = pthread_mutex_unlock(mutex); 100 return errorcode == 0; 101 } 102 103 bool 104 MutexImpl::tryacquire() 105 { 106 pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_); 107 assert(mutex != nullptr); 108 109 int errorcode = pthread_mutex_trylock(mutex); 110 return errorcode == 0; 111 } 112 113 } 114 115 #elif defined(LLVM_ON_UNIX) 116 #include "Unix/Mutex.inc" 117 #elif defined( LLVM_ON_WIN32) 118 #include "Windows/Mutex.inc" 119 #else 120 #warning Neither LLVM_ON_UNIX nor LLVM_ON_WIN32 was set in Support/Mutex.cpp 121 #endif 122 #endif 123
