Mutex.cpp revision 36b56886974eae4f9c5ebc96befd3e7bfe5de338 
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
24namespace llvm {
25using namespace sys;
26MutexImpl::MutexImpl( bool recursive) { }
27MutexImpl::~MutexImpl() { }
28bool MutexImpl::acquire() { return true; }
29bool MutexImpl::release() { return true; }
30bool 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
40namespace llvm {
41using namespace sys;
42
43// Construct a Mutex using pthread calls
44MutexImpl::MutexImpl( bool recursive)
45  : data_(0)
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
75MutexImpl::~MutexImpl()
76{
77  pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
78  assert(mutex != 0);
79  pthread_mutex_destroy(mutex);
80  free(mutex);
81}
82
83bool
84MutexImpl::acquire()
85{
86  pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
87  assert(mutex != 0);
88
89  int errorcode = pthread_mutex_lock(mutex);
90  return errorcode == 0;
91}
92
93bool
94MutexImpl::release()
95{
96  pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
97  assert(mutex != 0);
98
99  int errorcode = pthread_mutex_unlock(mutex);
100  return errorcode == 0;
101}
102
103bool
104MutexImpl::tryacquire()
105{
106  pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
107  assert(mutex != 0);
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