v8/src/unbound-queue-inl.h
yurys@chromium.org 3b53f7dc61 Fix data race in v8::internal::UnboundQueue
This change modifies memory accesses to ensure proper load/store ordering.

BUG=249750
R=dvyukov@google.com, jkummerow@chromium.org

Review URL: https://codereview.chromium.org/17294004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15219 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-06-20 06:23:34 +00:00

108 lines
3.3 KiB
C++

// Copyright 2010 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef V8_UNBOUND_QUEUE_INL_H_
#define V8_UNBOUND_QUEUE_INL_H_
#include "unbound-queue.h"
#include "atomicops.h"
namespace v8 {
namespace internal {
template<typename Record>
struct UnboundQueue<Record>::Node: public Malloced {
explicit Node(const Record& value)
: value(value), next(NULL) {
}
Record value;
Node* next;
};
template<typename Record>
UnboundQueue<Record>::UnboundQueue() {
first_ = new Node(Record());
divider_ = last_ = reinterpret_cast<AtomicWord>(first_);
}
template<typename Record>
UnboundQueue<Record>::~UnboundQueue() {
while (first_ != NULL) DeleteFirst();
}
template<typename Record>
void UnboundQueue<Record>::DeleteFirst() {
Node* tmp = first_;
first_ = tmp->next;
delete tmp;
}
template<typename Record>
bool UnboundQueue<Record>::Dequeue(Record* rec) {
if (divider_ == Acquire_Load(&last_)) return false;
Node* next = reinterpret_cast<Node*>(divider_)->next;
*rec = next->value;
Release_Store(&divider_, reinterpret_cast<AtomicWord>(next));
return true;
}
template<typename Record>
void UnboundQueue<Record>::Enqueue(const Record& rec) {
Node*& next = reinterpret_cast<Node*>(last_)->next;
next = new Node(rec);
Release_Store(&last_, reinterpret_cast<AtomicWord>(next));
while (first_ != reinterpret_cast<Node*>(Acquire_Load(&divider_))) {
DeleteFirst();
}
}
template<typename Record>
bool UnboundQueue<Record>::IsEmpty() const {
return NoBarrier_Load(&divider_) == NoBarrier_Load(&last_);
}
template<typename Record>
Record* UnboundQueue<Record>::Peek() const {
if (divider_ == Acquire_Load(&last_)) return NULL;
Node* next = reinterpret_cast<Node*>(divider_)->next;
return &next->value;
}
} } // namespace v8::internal
#endif // V8_UNBOUND_QUEUE_INL_H_