126 lines
3.2 KiB
C++
126 lines
3.2 KiB
C++
//===- RWMutex.cpp - Reader/Writer Mutual Exclusion Lock --------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the llvm::sys::RWMutex class.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Config/config.h"
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#include "llvm/Support/RWMutex.h"
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#include <cstring>
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//===----------------------------------------------------------------------===//
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//=== WARNING: Implementation here must contain only TRULY operating system
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//=== independent code.
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//===----------------------------------------------------------------------===//
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#if !defined(LLVM_ENABLE_THREADS) || LLVM_ENABLE_THREADS == 0
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// Define all methods as no-ops if threading is explicitly disabled
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namespace llvm {
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using namespace sys;
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RWMutexImpl::RWMutexImpl() { }
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RWMutexImpl::~RWMutexImpl() { }
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bool RWMutexImpl::reader_acquire() { return true; }
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bool RWMutexImpl::reader_release() { return true; }
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bool RWMutexImpl::writer_acquire() { return true; }
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bool RWMutexImpl::writer_release() { return true; }
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}
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#else
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#if defined(HAVE_PTHREAD_H) && defined(HAVE_PTHREAD_RWLOCK_INIT)
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#include <cassert>
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#include <pthread.h>
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#include <stdlib.h>
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namespace llvm {
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using namespace sys;
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// Construct a RWMutex using pthread calls
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RWMutexImpl::RWMutexImpl()
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: data_(0)
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{
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// Declare the pthread_rwlock data structures
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pthread_rwlock_t* rwlock =
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static_cast<pthread_rwlock_t*>(malloc(sizeof(pthread_rwlock_t)));
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#ifdef __APPLE__
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// Workaround a bug/mis-feature in Darwin's pthread_rwlock_init.
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bzero(rwlock, sizeof(pthread_rwlock_t));
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#endif
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// Initialize the rwlock
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int errorcode = pthread_rwlock_init(rwlock, NULL);
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(void)errorcode;
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assert(errorcode == 0);
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// Assign the data member
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data_ = rwlock;
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}
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// Destruct a RWMutex
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RWMutexImpl::~RWMutexImpl()
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{
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pthread_rwlock_t* rwlock = static_cast<pthread_rwlock_t*>(data_);
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assert(rwlock != 0);
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pthread_rwlock_destroy(rwlock);
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free(rwlock);
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}
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bool
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RWMutexImpl::reader_acquire()
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{
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pthread_rwlock_t* rwlock = static_cast<pthread_rwlock_t*>(data_);
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assert(rwlock != 0);
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int errorcode = pthread_rwlock_rdlock(rwlock);
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return errorcode == 0;
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}
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bool
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RWMutexImpl::reader_release()
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{
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pthread_rwlock_t* rwlock = static_cast<pthread_rwlock_t*>(data_);
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assert(rwlock != 0);
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int errorcode = pthread_rwlock_unlock(rwlock);
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return errorcode == 0;
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}
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bool
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RWMutexImpl::writer_acquire()
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{
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pthread_rwlock_t* rwlock = static_cast<pthread_rwlock_t*>(data_);
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assert(rwlock != 0);
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int errorcode = pthread_rwlock_wrlock(rwlock);
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return errorcode == 0;
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}
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bool
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RWMutexImpl::writer_release()
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{
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pthread_rwlock_t* rwlock = static_cast<pthread_rwlock_t*>(data_);
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assert(rwlock != 0);
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int errorcode = pthread_rwlock_unlock(rwlock);
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return errorcode == 0;
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}
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}
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#elif defined(LLVM_ON_UNIX)
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#include "Unix/RWMutex.inc"
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#elif defined( LLVM_ON_WIN32)
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#include "Windows/RWMutex.inc"
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#else
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#warning Neither LLVM_ON_UNIX nor LLVM_ON_WIN32 was set in Support/Mutex.cpp
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#endif
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#endif
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