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llvm-mirror/lib/Support/Mutex.cpp
Mark Seaborn c53fc2913b Remove unnecessary call to pthread_mutexattr_setpshared()
The default value of this attribute is PTHREAD_PROCESS_PRIVATE, so
there's no point in calling pthread_mutexattr_setpshared() to set
that.

See: http://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_mutexattr_getpshared.html

This removes some ifdefs that tend to need to be extended for other
platforms (e.g. for NaCl).

Note that this call was in the first implementation of Mutex, added in
r22403, so it doesn't appear to have been added in response to a
performance problem.

Differential Revision: http://llvm-reviews.chandlerc.com/D2633

llvm-svn: 200360
2014-01-29 00:20:44 +00:00

123 lines
3.2 KiB
C++

//===- Mutex.cpp - Mutual Exclusion Lock ------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the llvm::sys::Mutex class.
//
//===----------------------------------------------------------------------===//
#include "llvm/Config/config.h"
#include "llvm/Support/Mutex.h"
//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only TRULY operating system
//=== independent code.
//===----------------------------------------------------------------------===//
#if !defined(LLVM_ENABLE_THREADS) || LLVM_ENABLE_THREADS == 0
// Define all methods as no-ops if threading is explicitly disabled
namespace llvm {
using namespace sys;
MutexImpl::MutexImpl( bool recursive) { }
MutexImpl::~MutexImpl() { }
bool MutexImpl::acquire() { return true; }
bool MutexImpl::release() { return true; }
bool MutexImpl::tryacquire() { return true; }
}
#else
#if defined(HAVE_PTHREAD_H) && defined(HAVE_PTHREAD_MUTEX_LOCK)
#include <cassert>
#include <pthread.h>
#include <stdlib.h>
namespace llvm {
using namespace sys;
// Construct a Mutex using pthread calls
MutexImpl::MutexImpl( bool recursive)
: data_(0)
{
// Declare the pthread_mutex data structures
pthread_mutex_t* mutex =
static_cast<pthread_mutex_t*>(malloc(sizeof(pthread_mutex_t)));
pthread_mutexattr_t attr;
// Initialize the mutex attributes
int errorcode = pthread_mutexattr_init(&attr);
assert(errorcode == 0); (void)errorcode;
// Initialize the mutex as a recursive mutex, if requested, or normal
// otherwise.
int kind = ( recursive ? PTHREAD_MUTEX_RECURSIVE : PTHREAD_MUTEX_NORMAL );
errorcode = pthread_mutexattr_settype(&attr, kind);
assert(errorcode == 0);
// Initialize the mutex
errorcode = pthread_mutex_init(mutex, &attr);
assert(errorcode == 0);
// Destroy the attributes
errorcode = pthread_mutexattr_destroy(&attr);
assert(errorcode == 0);
// Assign the data member
data_ = mutex;
}
// Destruct a Mutex
MutexImpl::~MutexImpl()
{
pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
assert(mutex != 0);
pthread_mutex_destroy(mutex);
free(mutex);
}
bool
MutexImpl::acquire()
{
pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
assert(mutex != 0);
int errorcode = pthread_mutex_lock(mutex);
return errorcode == 0;
}
bool
MutexImpl::release()
{
pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
assert(mutex != 0);
int errorcode = pthread_mutex_unlock(mutex);
return errorcode == 0;
}
bool
MutexImpl::tryacquire()
{
pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
assert(mutex != 0);
int errorcode = pthread_mutex_trylock(mutex);
return errorcode == 0;
}
}
#elif defined(LLVM_ON_UNIX)
#include "Unix/Mutex.inc"
#elif defined( LLVM_ON_WIN32)
#include "Windows/Mutex.inc"
#else
#warning Neither LLVM_ON_UNIX nor LLVM_ON_WIN32 was set in Support/Mutex.cpp
#endif
#endif