Mutex.cpp revision 234353 
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#if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__) && !defined(__DragonFly__)
63  // Make it a process local mutex
64  errorcode = pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_PRIVATE);
65  assert(errorcode == 0);
66#endif
67
68  // Initialize the mutex
69  errorcode = pthread_mutex_init(mutex, &attr);
70  assert(errorcode == 0);
71
72  // Destroy the attributes
73  errorcode = pthread_mutexattr_destroy(&attr);
74  assert(errorcode == 0);
75
76  // Assign the data member
77  data_ = mutex;
78}
79
80// Destruct a Mutex
81MutexImpl::~MutexImpl()
82{
83  pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
84  assert(mutex != 0);
85  pthread_mutex_destroy(mutex);
86  free(mutex);
87}
88
89bool
90MutexImpl::acquire()
91{
92  pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
93  assert(mutex != 0);
94
95  int errorcode = pthread_mutex_lock(mutex);
96  return errorcode == 0;
97}
98
99bool
100MutexImpl::release()
101{
102  pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
103  assert(mutex != 0);
104
105  int errorcode = pthread_mutex_unlock(mutex);
106  return errorcode == 0;
107}
108
109bool
110MutexImpl::tryacquire()
111{
112  pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
113  assert(mutex != 0);
114
115  int errorcode = pthread_mutex_trylock(mutex);
116  return errorcode == 0;
117}
118
119}
120
121#elif defined(LLVM_ON_UNIX)
122#include "Unix/Mutex.inc"
123#elif defined( LLVM_ON_WIN32)
124#include "Windows/Mutex.inc"
125#else
126#warning Neither LLVM_ON_UNIX nor LLVM_ON_WIN32 was set in Support/Mutex.cpp
127#endif
128#endif
129