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/*
* Copyright (C) 2015-2018 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.
*/
#pragma once
#include "ObjectPropertyCondition.h"
#include <wtf/FastMalloc.h>
#include <wtf/Hasher.h>
#include <wtf/RefCountedFixedVector.h>
#include <wtf/Vector.h>
WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN
namespace JSC {
// An object property condition set is used to represent the set of additional conditions
// that need to be met for some heap access to be valid. The set can have the following
// interesting states:
//
// Empty: There are no special conditions that need to be met.
// Invalid: The heap access is never valid.
// Non-empty: The heap access is valid if all the ObjectPropertyConditions in the set are valid.
class ObjectPropertyConditionSet {
public:
using Conditions = ThreadSafeRefCountedFixedVector<ObjectPropertyCondition>;
ObjectPropertyConditionSet() = default;
static ObjectPropertyConditionSet invalid()
{
ObjectPropertyConditionSet result;
result.m_data = Conditions::create(0);
ASSERT(!result.isValid());
return result;
}
template<typename Vector>
static ObjectPropertyConditionSet create(Vector&& vector)
{
if (vector.isEmpty())
return ObjectPropertyConditionSet();
ObjectPropertyConditionSet result;
result.m_data = Conditions::createFromVector(std::forward<Vector>(vector));
ASSERT(result.isValid());
return result;
}
bool isValid() const
{
return !m_data || !m_data->isEmpty();
}
size_t size() const { return m_data ? m_data->size() : 0; }
bool isEmpty() const
{
return !m_data;
}
using const_iterator = Conditions::const_iterator;
const_iterator begin() const
{
if (!m_data)
return nullptr;
return m_data->cbegin();
}
const_iterator end() const
{
if (!m_data)
return nullptr;
return m_data->cend();
}
unsigned hash() const
{
Hasher hasher;
for (auto& condition : *this)
add(hasher, condition.hash());
return hasher.hash();
}
friend bool operator==(const ObjectPropertyConditionSet& lhs, const ObjectPropertyConditionSet& rhs)
{
if (lhs.size() != rhs.size())
return false;
auto liter = lhs.begin();
auto riter = rhs.begin();
for (; liter != lhs.end(); ++liter, ++riter) {
if (!(*liter == *riter))
return false;
}
return true;
}
ObjectPropertyCondition forObject(JSObject*) const;
ObjectPropertyCondition forConditionKind(PropertyCondition::Kind) const;
unsigned numberOfConditionsWithKind(PropertyCondition::Kind) const;
bool hasOneSlotBaseCondition() const;
// If this is a condition set for a prototype hit, then this is guaranteed to return the
// condition on the prototype itself. This allows you to get the object, offset, and
// attributes for the prototype. This will RELEASE_ASSERT that there is exactly one Presence
// in the set, and it will return that presence.
ObjectPropertyCondition slotBaseCondition() const;
// Attempt to create a new condition set by merging this one with the other one. This will
// fail if any of the conditions are incompatible with each other. When if fails, it returns
// invalid().
ObjectPropertyConditionSet mergedWith(const ObjectPropertyConditionSet& other) const;
bool isStillValid() const;
bool structuresEnsureValidity() const;
bool needImpurePropertyWatchpoint() const;
template<typename Functor>
void forEachDependentCell(const Functor& functor) const
{
for (const ObjectPropertyCondition& condition : *this)
condition.forEachDependentCell(functor);
}
bool areStillLive(VM&) const;
void dumpInContext(PrintStream&, DumpContext*) const;
void dump(PrintStream&) const;
// Internally, this represents Invalid using a pointer to a Data that has an empty vector.
// FIXME: This could be made more compact by having it internally use a vector that just has
// the non-uid portion of ObjectPropertyCondition, and then requiring that the callers of all
// of the APIs supply the uid.
private:
RefPtr<Conditions> m_data;
};
ObjectPropertyCondition generateConditionForSelfEquivalence(
VM&, JSCell* owner, JSObject* object, UniquedStringImpl* uid);
ObjectPropertyConditionSet generateConditionsForPropertyMiss(
VM&, JSCell* owner, JSGlobalObject*, Structure* headStructure, UniquedStringImpl* uid);
ObjectPropertyConditionSet generateConditionsForPropertySetterMiss(
VM&, JSCell* owner, JSGlobalObject*, Structure* headStructure, UniquedStringImpl* uid);
ObjectPropertyConditionSet generateConditionsForIndexedMiss(VM&, JSCell* owner, JSGlobalObject*, Structure* headStructure);
ObjectPropertyConditionSet generateConditionsForPrototypePropertyHit(
VM&, JSCell* owner, JSGlobalObject*, Structure* headStructure, JSObject* prototype,
UniquedStringImpl* uid);
ObjectPropertyConditionSet generateConditionsForPrototypePropertyHitCustom(
VM&, JSCell* owner, JSGlobalObject*, Structure* headStructure, JSObject* prototype,
UniquedStringImpl* uid, unsigned attributes);
ObjectPropertyConditionSet generateConditionsForInstanceOf(
VM&, JSCell* owner, JSGlobalObject*, Structure* headStructure, JSObject* prototype, bool shouldHit);
ObjectPropertyConditionSet generateConditionsForPrototypeEquivalenceConcurrently(
VM&, JSGlobalObject*, Structure* headStructure, JSObject* prototype,
UniquedStringImpl* uid);
ObjectPropertyConditionSet generateConditionsForPropertyMissConcurrently(
VM&, JSGlobalObject*, Structure* headStructure, UniquedStringImpl* uid);
ObjectPropertyConditionSet generateConditionsForPropertySetterMissConcurrently(
VM&, JSGlobalObject*, Structure* headStructure, UniquedStringImpl* uid);
struct PrototypeChainCachingStatus {
bool usesPolyProto;
bool flattenedDictionary;
};
std::optional<PrototypeChainCachingStatus> prepareChainForCaching(JSGlobalObject*, JSCell* base, UniquedStringImpl*, const PropertySlot&);
std::optional<PrototypeChainCachingStatus> prepareChainForCaching(JSGlobalObject*, JSCell* base, UniquedStringImpl*, JSObject* target);
std::optional<PrototypeChainCachingStatus> prepareChainForCaching(JSGlobalObject*, Structure* base, UniquedStringImpl*, JSObject* target);
} // namespace JSC
WTF_ALLOW_UNSAFE_BUFFER_USAGE_END
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