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  • Committer: Package Import Robot
  • Author(s): Sylvestre Ledru
  • Date: 2015-07-15 17:51:08 UTC
  • Revision ID: package-import@ubuntu.com-20150715175108-l8mynwovkx4zx697
Tags: upstream-3.7~+rc2
Import upstream version 3.7~+rc2

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lib/Support/RWMutex.cpp
 
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//===- 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_(nullptr)
 
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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, nullptr);
 
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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 != nullptr);
 
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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 != nullptr);
 
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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 != nullptr);
 
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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 != nullptr);
 
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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 != nullptr);
 
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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