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/Support/Mutex.h" 15 #include "llvm/Config/config.h" 16 #include "llvm/Support/ErrorHandling.h" 17 18 //===----------------------------------------------------------------------===// 19 //=== WARNING: Implementation here must contain only TRULY operating system 20 //=== independent code. 21 //===----------------------------------------------------------------------===// 22 23 #if !defined(LLVM_ENABLE_THREADS) || LLVM_ENABLE_THREADS == 0 24 // Define all methods as no-ops if threading is explicitly disabled 25 namespace llvm { 26 using namespace sys; 27 MutexImpl::MutexImpl( bool recursive) { } 28 MutexImpl::~MutexImpl() { } 29 bool MutexImpl::acquire() { return true; } 30 bool MutexImpl::release() { return true; } 31 bool MutexImpl::tryacquire() { return true; } 32 } 33 #else 34 35 #if defined(HAVE_PTHREAD_H) && defined(HAVE_PTHREAD_MUTEX_LOCK) 36 37 #include <cassert> 38 #include <pthread.h> 39 #include <stdlib.h> 40 41 namespace llvm { 42 using namespace sys; 43 44 // Construct a Mutex using pthread calls 45 MutexImpl::MutexImpl( bool recursive) 46 : data_(nullptr) 47 { 48 // Declare the pthread_mutex data structures 49 pthread_mutex_t* mutex = 50 static_cast<pthread_mutex_t*>(safe_malloc(sizeof(pthread_mutex_t))); 51 52 pthread_mutexattr_t attr; 53 54 // Initialize the mutex attributes 55 int errorcode = pthread_mutexattr_init(&attr); 56 assert(errorcode == 0); (void)errorcode; 57 58 // Initialize the mutex as a recursive mutex, if requested, or normal 59 // otherwise. 60 int kind = ( recursive ? PTHREAD_MUTEX_RECURSIVE : PTHREAD_MUTEX_NORMAL ); 61 errorcode = pthread_mutexattr_settype(&attr, kind); 62 assert(errorcode == 0); 63 64 // Initialize the mutex 65 errorcode = pthread_mutex_init(mutex, &attr); 66 assert(errorcode == 0); 67 68 // Destroy the attributes 69 errorcode = pthread_mutexattr_destroy(&attr); 70 assert(errorcode == 0); 71 72 // Assign the data member 73 data_ = mutex; 74 } 75 76 // Destruct a Mutex 77 MutexImpl::~MutexImpl() 78 { 79 pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_); 80 assert(mutex != nullptr); 81 pthread_mutex_destroy(mutex); 82 free(mutex); 83 } 84 85 bool 86 MutexImpl::acquire() 87 { 88 pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_); 89 assert(mutex != nullptr); 90 91 int errorcode = pthread_mutex_lock(mutex); 92 return errorcode == 0; 93 } 94 95 bool 96 MutexImpl::release() 97 { 98 pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_); 99 assert(mutex != nullptr); 100 101 int errorcode = pthread_mutex_unlock(mutex); 102 return errorcode == 0; 103 } 104 105 bool 106 MutexImpl::tryacquire() 107 { 108 pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_); 109 assert(mutex != nullptr); 110 111 int errorcode = pthread_mutex_trylock(mutex); 112 return errorcode == 0; 113 } 114 115 } 116 117 #elif defined(LLVM_ON_UNIX) 118 #include "Unix/Mutex.inc" 119 #elif defined( _WIN32) 120 #include "Windows/Mutex.inc" 121 #else 122 #warning Neither LLVM_ON_UNIX nor _WIN32 was set in Support/Mutex.cpp 123 #endif 124 #endif 125
