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/*
* Copyright (C) 2012-2021 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 "CacheableIdentifier.h"
#include "CallLinkStatus.h"
#include "CodeOrigin.h"
#include "ConcurrentJSLock.h"
#include "ExitFlag.h"
#include "GetByVariant.h"
#include "ICStatusMap.h"
#include "InlineCacheCompiler.h"
#include "ScopeOffset.h"
#include "StubInfoSummary.h"
namespace JSC {
class AccessCase;
class CodeBlock;
class JSModuleEnvironment;
class JSModuleNamespaceObject;
class ModuleNamespaceAccessCase;
class StructureStubInfo;
enum class CacheType : int8_t;
DECLARE_ALLOCATOR_WITH_HEAP_IDENTIFIER(GetByStatus);
class GetByStatus final {
WTF_MAKE_FAST_ALLOCATED_WITH_HEAP_IDENTIFIER(GetByStatus);
public:
enum State : uint8_t {
// 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 custom accessor with a possible structure chain.
CustomAccessor,
// It's cached for a megamorphic case.
Megamorphic,
// It's cached for an access to a module namespace object's binding.
ModuleNamespace,
// It's cached for an access to a proxy object's binding.
ProxyObject,
// It will likely take the slow path.
LikelyTakesSlowPath,
// It's known to take slow path. We also observed that the slow path was taken on StructureStubInfo.
ObservedTakesSlowPath,
// It will likely take the slow path and will make calls.
MakesCalls,
// It known to take paths that make calls. We also observed that the slow path was taken on StructureStubInfo.
ObservedSlowPathAndMakesCalls,
};
GetByStatus()
: m_state(NoInformation)
{
}
explicit GetByStatus(State state)
: m_state(state)
{
ASSERT(state == NoInformation || state == LikelyTakesSlowPath || state == ObservedTakesSlowPath || state == MakesCalls || state == ObservedSlowPathAndMakesCalls);
}
explicit GetByStatus(StubInfoSummary, StructureStubInfo*);
GetByStatus(
State state, bool wasSeenInJIT)
: m_state(state)
, m_wasSeenInJIT(wasSeenInJIT)
{
}
static GetByStatus computeFor(CodeBlock* baselineBlock, ICStatusMap& baselineMap, ICStatusContextStack& dfgContextStack, CodeOrigin);
static GetByStatus computeFor(const StructureSet&, UniquedStringImpl*);
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 isCustomAccessor() const { return m_state == CustomAccessor; }
bool isMegamorphic() const { return m_state == Megamorphic; }
bool isModuleNamespace() const { return m_state == ModuleNamespace; }
bool isProxyObject() const { return m_state == ProxyObject; }
size_t numVariants() const { return m_variants.size(); }
const Vector<GetByVariant, 1>& variants() const { return m_variants; }
const GetByVariant& at(size_t index) const { return m_variants[index]; }
const GetByVariant& operator[](size_t index) const { return at(index); }
bool takesSlowPath() const
{
return m_state == LikelyTakesSlowPath || m_state == ObservedTakesSlowPath || m_state == MakesCalls || m_state == ObservedSlowPathAndMakesCalls || m_state == CustomAccessor || m_state == ModuleNamespace || m_state == Megamorphic;
}
bool observedStructureStubInfoSlowPath() const { return m_state == ObservedTakesSlowPath || m_state == ObservedSlowPathAndMakesCalls; }
bool makesCalls() const;
GetByStatus slowVersion() const;
bool wasSeenInJIT() const { return m_wasSeenInJIT; }
// Attempts to reduce the set of variants to fit the given structure set. This may be approximate.
void filter(const StructureSet&);
JSModuleNamespaceObject* moduleNamespaceObject() const { return m_moduleNamespaceData->m_moduleNamespaceObject; }
JSModuleEnvironment* moduleEnvironment() const { return m_moduleNamespaceData->m_moduleEnvironment; }
ScopeOffset scopeOffset() const { return m_moduleNamespaceData->m_scopeOffset; }
DECLARE_VISIT_AGGREGATE;
template<typename Visitor> void markIfCheap(Visitor&);
bool finalize(VM&); // Return true if this gets to live.
bool appendVariant(const GetByVariant&);
void shrinkToFit();
void dump(PrintStream&) const;
CacheableIdentifier singleIdentifier() const;
bool viaGlobalProxy() const
{
if (m_variants.isEmpty())
return false;
return m_variants.first().viaGlobalProxy();
}
#if ENABLE(JIT)
CacheType preferredCacheType() const;
#endif
private:
void merge(const GetByStatus&);
#if ENABLE(JIT)
GetByStatus(const ModuleNamespaceAccessCase&);
static GetByStatus computeForStubInfoWithoutExitSiteFeedback(const ConcurrentJSLocker&, CodeBlock* profiledBlock, StructureStubInfo*, CallLinkStatus::ExitSiteData, CodeOrigin);
#endif
static GetByStatus computeFromLLInt(CodeBlock*, BytecodeIndex);
static GetByStatus computeFor(CodeBlock*, ICStatusMap&, ExitFlag, CallLinkStatus::ExitSiteData, CodeOrigin);
struct ModuleNamespaceData {
JSModuleNamespaceObject* m_moduleNamespaceObject { nullptr };
JSModuleEnvironment* m_moduleEnvironment { nullptr };
ScopeOffset m_scopeOffset { };
CacheableIdentifier m_identifier;
};
Vector<GetByVariant, 1> m_variants;
Box<ModuleNamespaceData> m_moduleNamespaceData;
State m_state;
bool m_wasSeenInJIT : 1 { false };
bool m_containsDOMGetter : 1 { false };
};
} // namespace JSC
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