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/*
* Copyright (C) 2008, 2009, 2013 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.
*/
#ifndef StructureTransitionTable_h
#define StructureTransitionTable_h
#include "IndexingType.h"
#include "WeakGCMap.h"
#include <wtf/HashFunctions.h>
#include <wtf/text/UniquedStringImpl.h>
namespace JSC {
class JSCell;
class Structure;
static const unsigned FirstInternalAttribute = 1 << 6; // Use for transitions that don't have to do with property additions.
// Support for attributes used to indicate transitions not related to properties.
// If any of these are used, the string portion of the key should be 0.
enum NonPropertyTransition {
AllocateUndecided,
AllocateInt32,
AllocateDouble,
AllocateContiguous,
AllocateArrayStorage,
AllocateSlowPutArrayStorage,
SwitchToSlowPutArrayStorage,
AddIndexedAccessors
};
inline unsigned toAttributes(NonPropertyTransition transition)
{
return transition + FirstInternalAttribute;
}
inline IndexingType newIndexingType(IndexingType oldType, NonPropertyTransition transition)
{
switch (transition) {
case AllocateUndecided:
ASSERT(!hasIndexedProperties(oldType));
return oldType | UndecidedShape;
case AllocateInt32:
ASSERT(!hasIndexedProperties(oldType) || hasUndecided(oldType));
return (oldType & ~IndexingShapeMask) | Int32Shape;
case AllocateDouble:
ASSERT(!hasIndexedProperties(oldType) || hasUndecided(oldType) || hasInt32(oldType));
return (oldType & ~IndexingShapeMask) | DoubleShape;
case AllocateContiguous:
ASSERT(!hasIndexedProperties(oldType) || hasUndecided(oldType) || hasInt32(oldType) || hasDouble(oldType));
return (oldType & ~IndexingShapeMask) | ContiguousShape;
case AllocateArrayStorage:
ASSERT(!hasIndexedProperties(oldType) || hasUndecided(oldType) || hasInt32(oldType) || hasDouble(oldType) || hasContiguous(oldType));
return (oldType & ~IndexingShapeMask) | ArrayStorageShape;
case AllocateSlowPutArrayStorage:
ASSERT(!hasIndexedProperties(oldType) || hasUndecided(oldType) || hasInt32(oldType) || hasDouble(oldType) || hasContiguous(oldType) || hasContiguous(oldType));
return (oldType & ~IndexingShapeMask) | SlowPutArrayStorageShape;
case SwitchToSlowPutArrayStorage:
ASSERT(hasArrayStorage(oldType));
return (oldType & ~IndexingShapeMask) | SlowPutArrayStorageShape;
case AddIndexedAccessors:
return oldType | MayHaveIndexedAccessors;
default:
RELEASE_ASSERT_NOT_REACHED();
return oldType;
}
}
class StructureTransitionTable {
static const intptr_t UsingSingleSlotFlag = 1;
struct Hash {
typedef std::pair<UniquedStringImpl*, unsigned> Key;
static unsigned hash(const Key& p)
{
return PtrHash<UniquedStringImpl*>::hash(p.first) + p.second;
}
static bool equal(const Key& a, const Key& b)
{
return a == b;
}
static const bool safeToCompareToEmptyOrDeleted = true;
};
typedef WeakGCMap<Hash::Key, Structure, Hash> TransitionMap;
public:
StructureTransitionTable()
: m_data(UsingSingleSlotFlag)
{
}
~StructureTransitionTable()
{
if (!isUsingSingleSlot()) {
delete map();
return;
}
WeakImpl* impl = this->weakImpl();
if (!impl)
return;
WeakSet::deallocate(impl);
}
void add(VM&, Structure*);
bool contains(UniquedStringImpl*, unsigned attributes) const;
Structure* get(UniquedStringImpl*, unsigned attributes) const;
private:
friend class SingleSlotTransitionWeakOwner;
bool isUsingSingleSlot() const
{
return m_data & UsingSingleSlotFlag;
}
TransitionMap* map() const
{
ASSERT(!isUsingSingleSlot());
return reinterpret_cast<TransitionMap*>(m_data);
}
WeakImpl* weakImpl() const
{
ASSERT(isUsingSingleSlot());
return reinterpret_cast<WeakImpl*>(m_data & ~UsingSingleSlotFlag);
}
void setMap(TransitionMap* map)
{
ASSERT(isUsingSingleSlot());
if (WeakImpl* impl = this->weakImpl())
WeakSet::deallocate(impl);
// This implicitly clears the flag that indicates we're using a single transition
m_data = reinterpret_cast<intptr_t>(map);
ASSERT(!isUsingSingleSlot());
}
Structure* singleTransition() const;
void setSingleTransition(Structure*);
intptr_t m_data;
};
} // namespace JSC
#endif // StructureTransitionTable_h
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