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/*
* Copyright (C) 2014 Google 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:
*
* * 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.
*/
#include "config.h"
#include "platform/heap/Visitor.h"
#include "platform/heap/Handle.h"
#include "platform/heap/Heap.h"
namespace blink {
// GCInfo indices start from 1 for heap objects, with 0 being treated
// specially as the index for freelist entries and large heap objects.
int GCInfoTable::s_gcInfoIndex = 0;
size_t GCInfoTable::s_gcInfoTableSize = 0;
GCInfo const** s_gcInfoTable = nullptr;
void GCInfoTable::ensureGCInfoIndex(const GCInfo* gcInfo, size_t* gcInfoIndexSlot)
{
ASSERT(gcInfo);
ASSERT(gcInfoIndexSlot);
// Keep a global GCInfoTable lock while allocating a new slot.
AtomicallyInitializedStatic(Mutex&, mutex = *new Mutex);
MutexLocker locker(mutex);
// If more than one thread ends up allocating a slot for
// the same GCInfo, have later threads reuse the slot
// allocated by the first.
if (*gcInfoIndexSlot)
return;
int index = ++s_gcInfoIndex;
size_t gcInfoIndex = static_cast<size_t>(index);
ASSERT(gcInfoIndex < GCInfoTable::maxIndex);
if (gcInfoIndex >= s_gcInfoTableSize)
resize();
s_gcInfoTable[gcInfoIndex] = gcInfo;
releaseStore(reinterpret_cast<int*>(gcInfoIndexSlot), index);
}
void GCInfoTable::resize()
{
// (Light) experimentation suggests that Blink doesn't need
// more than this while handling content on popular web properties.
const size_t initialSize = 512;
size_t newSize = s_gcInfoTableSize ? 2 * s_gcInfoTableSize : initialSize;
ASSERT(newSize < GCInfoTable::maxIndex);
s_gcInfoTable = reinterpret_cast<GCInfo const**>(realloc(s_gcInfoTable, newSize * sizeof(GCInfo)));
ASSERT(s_gcInfoTable);
memset(reinterpret_cast<uint8_t*>(s_gcInfoTable) + s_gcInfoTableSize * sizeof(GCInfo), 0, (newSize - s_gcInfoTableSize) * sizeof(GCInfo));
s_gcInfoTableSize = newSize;
}
void GCInfoTable::init()
{
RELEASE_ASSERT(!s_gcInfoTable);
resize();
}
void GCInfoTable::shutdown()
{
free(s_gcInfoTable);
s_gcInfoTable = nullptr;
}
StackFrameDepth* Visitor::m_stackFrameDepth = nullptr;
#if ENABLE(ASSERT)
void assertObjectHasGCInfo(const void* payload, size_t gcInfoIndex)
{
HeapObjectHeader::fromPayload(payload)->checkHeader();
#if !defined(COMPONENT_BUILD)
// On component builds we cannot compare the gcInfos as they are statically
// defined in each of the components and hence will not match.
BaseHeapPage* page = pageFromObject(payload);
ASSERT(page->orphaned() || HeapObjectHeader::fromPayload(payload)->gcInfoIndex() == gcInfoIndex);
#endif
}
#endif
}
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