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/*
* Copyright (C) 2018 Yusuke Suzuki <utatane.tea@gmail.com>.
* Copyright (C) 2018-2023 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 "CallLinkStatus.h"
#include "CodeOrigin.h"
#include "ConcurrentJSLock.h"
#include "ICStatusMap.h"
#include "InByVariant.h"
#include "StubInfoSummary.h"
#include <wtf/TZoneMalloc.h>
namespace JSC {
class AccessCase;
class CodeBlock;
class StructureStubInfo;
class InByStatus final {
WTF_MAKE_TZONE_ALLOCATED(InByStatus);
public:
enum State {
// It's uncached so we have no information.
NoInformation,
// It's cached for a simple access to a known object property with
// a possible structure chain and a possible specific value.
Simple,
// It's cached for a proxy object case.
ProxyObject,
// It's cached for a megamorphic case.
Megamorphic,
// It's known to often take slow path.
TakesSlowPath,
};
InByStatus() = default;
InByStatus(State state)
: m_state(state)
{
ASSERT(state != Simple);
}
explicit InByStatus(StubInfoSummary summary)
{
switch (summary) {
case StubInfoSummary::NoInformation:
m_state = NoInformation;
return;
case StubInfoSummary::Simple:
case StubInfoSummary::Megamorphic:
case StubInfoSummary::MakesCalls:
RELEASE_ASSERT_NOT_REACHED();
return;
case StubInfoSummary::TakesSlowPath:
case StubInfoSummary::TakesSlowPathAndMakesCalls:
m_state = TakesSlowPath;
return;
}
RELEASE_ASSERT_NOT_REACHED();
}
static InByStatus computeFor(CodeBlock*, ICStatusMap&, BytecodeIndex, ExitFlag, CallLinkStatus::ExitSiteData callExitSiteData, CodeOrigin);
static InByStatus computeFor(CodeBlock* baselineBlock, ICStatusMap& baselineMap, ICStatusContextStack&, CodeOrigin);
State state() const { return m_state; }
bool isSet() const { return m_state != NoInformation; }
explicit operator bool() const { return isSet(); }
bool isSimple() const { return m_state == Simple; }
bool isMegamorphic() const { return m_state == Megamorphic; }
bool isProxyObject() const { return m_state == ProxyObject; }
size_t numVariants() const { return m_variants.size(); }
const Vector<InByVariant, 1>& variants() const { return m_variants; }
const InByVariant& at(size_t index) const { return m_variants[index]; }
const InByVariant& operator[](size_t index) const { return at(index); }
bool takesSlowPath() const { return m_state == Megamorphic || m_state == TakesSlowPath; }
void merge(const InByStatus&);
// Attempts to reduce the set of variants to fit the given structure set. This may be approximate.
void filter(const StructureSet&);
DECLARE_VISIT_AGGREGATE;
template<typename Visitor> void markIfCheap(Visitor&);
bool finalize(VM&);
void dump(PrintStream&) const;
CacheableIdentifier singleIdentifier() const;
private:
#if ENABLE(DFG_JIT)
static InByStatus computeForStubInfoWithoutExitSiteFeedback(const ConcurrentJSLocker&, CodeBlock*, StructureStubInfo*, CallLinkStatus::ExitSiteData, CodeOrigin);
#endif
bool appendVariant(const InByVariant&);
void shrinkToFit();
State m_state { NoInformation };
Vector<InByVariant, 1> m_variants;
};
} // namespace JSC
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