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Diffstat (limited to 'contrib/llvm/lib/System/Mutex.cpp')
-rw-r--r-- | contrib/llvm/lib/System/Mutex.cpp | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/contrib/llvm/lib/System/Mutex.cpp b/contrib/llvm/lib/System/Mutex.cpp new file mode 100644 index 0000000..8ccd6e5 --- /dev/null +++ b/contrib/llvm/lib/System/Mutex.cpp @@ -0,0 +1,157 @@ +//===- 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/System/Mutex.h" + +//===----------------------------------------------------------------------===// +//=== WARNING: Implementation here must contain only TRULY operating system +//=== independent code. +//===----------------------------------------------------------------------===// + +#if !defined(ENABLE_THREADS) || 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; + + +// This variable is useful for situations where the pthread library has been +// compiled with weak linkage for its interface symbols. This allows the +// threading support to be turned off by simply not linking against -lpthread. +// In that situation, the value of pthread_mutex_init will be 0 and +// consequently pthread_enabled will be false. In such situations, all the +// pthread operations become no-ops and the functions all return false. If +// pthread_mutex_init does have an address, then mutex support is enabled. +// Note: all LLVM tools will link against -lpthread if its available since it +// is configured into the LIBS variable. +// Note: this line of code generates a warning if pthread_mutex_init is not +// declared with weak linkage. It's safe to ignore the warning. +static const bool pthread_enabled = true; + +// Construct a Mutex using pthread calls +MutexImpl::MutexImpl( bool recursive) + : data_(0) +{ + if (pthread_enabled) + { + // 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); + + // 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); + +#if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__) && !defined(__DragonFly__) + // Make it a process local mutex + errorcode = pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_PRIVATE); +#endif + + // 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() +{ + if (pthread_enabled) + { + pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_); + assert(mutex != 0); + pthread_mutex_destroy(mutex); + free(mutex); + } +} + +bool +MutexImpl::acquire() +{ + if (pthread_enabled) + { + pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_); + assert(mutex != 0); + + int errorcode = pthread_mutex_lock(mutex); + return errorcode == 0; + } else return false; +} + +bool +MutexImpl::release() +{ + if (pthread_enabled) + { + pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_); + assert(mutex != 0); + + int errorcode = pthread_mutex_unlock(mutex); + return errorcode == 0; + } else return false; +} + +bool +MutexImpl::tryacquire() +{ + if (pthread_enabled) + { + pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_); + assert(mutex != 0); + + int errorcode = pthread_mutex_trylock(mutex); + return errorcode == 0; + } else return false; +} + +} + +#elif defined(LLVM_ON_UNIX) +#include "Unix/Mutex.inc" +#elif defined( LLVM_ON_WIN32) +#include "Win32/Mutex.inc" +#else +#warning Neither LLVM_ON_UNIX nor LLVM_ON_WIN32 was set in System/Mutex.cpp +#endif +#endif + |