| /* |
| * Copyright (C) 2017-2019 Apple Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. 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. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 APPLE INC. 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. |
| */ |
| |
| #include "IsoTLSLayout.h" |
| |
| #include "IsoTLSEntry.h" |
| |
| namespace bmalloc { |
| |
| DEFINE_STATIC_PER_PROCESS_STORAGE(IsoTLSLayout); |
| |
| IsoTLSLayout::IsoTLSLayout(const LockHolder&) |
| { |
| } |
| |
| void IsoTLSLayout::add(IsoTLSEntry* entry) |
| { |
| static Mutex addingMutex; |
| RELEASE_BASSERT(!entry->m_next); |
| // IsoTLSLayout::head() does not take a lock. So we should emit memory fence to make sure that newly added entry is initialized when it is chained to this linked-list. |
| // Emitting memory fence here is OK since this function is not frequently called. |
| LockHolder locking(addingMutex); |
| if (m_head) { |
| RELEASE_BASSERT(m_tail); |
| size_t offset = roundUpToMultipleOf(entry->alignment(), m_tail->extent()); |
| RELEASE_BASSERT(offset < UINT_MAX); |
| entry->m_offset = offset; |
| std::atomic_thread_fence(std::memory_order_seq_cst); |
| m_tail->m_next = entry; |
| m_tail = entry; |
| } else { |
| RELEASE_BASSERT(!m_tail); |
| entry->m_offset = 0; |
| std::atomic_thread_fence(std::memory_order_seq_cst); |
| m_head = entry; |
| m_tail = entry; |
| } |
| } |
| |
| } // namespace bmalloc |
| |