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/*
* Copyright (C) 2012-2020 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.
*/
#include "config.h"
#include "GetByStatus.h"
#include "BytecodeStructs.h"
#include "CacheableIdentifierInlines.h"
#include "CodeBlock.h"
#include "ComplexGetStatus.h"
#include "GetterSetterAccessCase.h"
#include "ICStatusUtils.h"
#include "InterpreterInlines.h"
#include "IntrinsicGetterAccessCase.h"
#include "JSCInlines.h"
#include "JSScope.h"
#include "LLIntData.h"
#include "LowLevelInterpreter.h"
#include "ModuleNamespaceAccessCase.h"
#include "PolymorphicAccess.h"
#include "StructureStubInfo.h"
#include <wtf/ListDump.h>
namespace JSC {
namespace DOMJIT {
class GetterSetter;
}
bool GetByStatus::appendVariant(const GetByIdVariant& variant)
{
return appendICStatusVariant(m_variants, variant);
}
GetByStatus GetByStatus::computeFromLLInt(CodeBlock* profiledBlock, BytecodeIndex bytecodeIndex)
{
VM& vm = profiledBlock->vm();
auto instruction = profiledBlock->instructions().at(bytecodeIndex.offset());
StructureID structureID;
const Identifier* identifier = nullptr;
switch (instruction->opcodeID()) {
case op_get_by_id: {
auto& metadata = instruction->as<OpGetById>().metadata(profiledBlock);
// FIXME: We should not just bail if we see a get_by_id_proto_load.
// https://bugs.webkit.org/show_bug.cgi?id=158039
if (metadata.m_modeMetadata.mode != GetByIdMode::Default)
return GetByStatus(NoInformation, false);
structureID = metadata.m_modeMetadata.defaultMode.structureID;
identifier = &(profiledBlock->identifier(instruction->as<OpGetById>().m_property));
break;
}
case op_get_by_id_direct:
structureID = instruction->as<OpGetByIdDirect>().metadata(profiledBlock).m_structureID;
identifier = &(profiledBlock->identifier(instruction->as<OpGetByIdDirect>().m_property));
break;
case op_try_get_by_id: {
// FIXME: We should not just bail if we see a try_get_by_id.
// https://bugs.webkit.org/show_bug.cgi?id=158039
return GetByStatus(NoInformation, false);
}
case op_get_by_val:
return GetByStatus(NoInformation, false);
default: {
ASSERT_NOT_REACHED();
return GetByStatus(NoInformation, false);
}
}
if (!structureID)
return GetByStatus(NoInformation, false);
Structure* structure = vm.heap.structureIDTable().get(structureID);
if (structure->takesSlowPathInDFGForImpureProperty())
return GetByStatus(NoInformation, false);
unsigned attributes;
PropertyOffset offset = structure->getConcurrently(identifier->impl(), attributes);
if (!isValidOffset(offset))
return GetByStatus(NoInformation, false);
if (attributes & PropertyAttribute::CustomAccessorOrValue)
return GetByStatus(NoInformation, false);
GetByStatus result(Simple, false);
result.appendVariant(GetByIdVariant(nullptr, StructureSet(structure), offset));
return result;
}
GetByStatus GetByStatus::computeFor(CodeBlock* profiledBlock, ICStatusMap& map, BytecodeIndex bytecodeIndex, ExitFlag didExit, CallLinkStatus::ExitSiteData callExitSiteData)
{
ConcurrentJSLocker locker(profiledBlock->m_lock);
GetByStatus result;
#if ENABLE(DFG_JIT)
result = computeForStubInfoWithoutExitSiteFeedback(
locker, profiledBlock, map.get(CodeOrigin(bytecodeIndex)).stubInfo, callExitSiteData);
if (didExit)
return result.slowVersion();
#else
UNUSED_PARAM(map);
UNUSED_PARAM(didExit);
UNUSED_PARAM(callExitSiteData);
#endif
if (!result)
return computeFromLLInt(profiledBlock, bytecodeIndex);
return result;
}
#if ENABLE(JIT)
GetByStatus::GetByStatus(StubInfoSummary summary, StructureStubInfo& stubInfo)
: m_wasSeenInJIT(true)
{
switch (summary) {
case StubInfoSummary::NoInformation:
m_state = NoInformation;
return;
case StubInfoSummary::Simple:
case StubInfoSummary::MakesCalls:
RELEASE_ASSERT_NOT_REACHED();
return;
case StubInfoSummary::TakesSlowPath:
m_state = stubInfo.tookSlowPath ? ObservedTakesSlowPath : LikelyTakesSlowPath;
return;
case StubInfoSummary::TakesSlowPathAndMakesCalls:
m_state = stubInfo.tookSlowPath ? ObservedSlowPathAndMakesCalls : MakesCalls;
return;
}
RELEASE_ASSERT_NOT_REACHED();
}
GetByStatus::GetByStatus(const ModuleNamespaceAccessCase& accessCase)
: m_moduleNamespaceData(Box<ModuleNamespaceData>::create(ModuleNamespaceData { accessCase.moduleNamespaceObject(), accessCase.moduleEnvironment(), accessCase.scopeOffset(), accessCase.identifier() }))
, m_state(ModuleNamespace)
, m_wasSeenInJIT(true)
{
}
GetByStatus GetByStatus::computeForStubInfoWithoutExitSiteFeedback(
const ConcurrentJSLocker& locker, CodeBlock* profiledBlock, StructureStubInfo* stubInfo, CallLinkStatus::ExitSiteData callExitSiteData)
{
StubInfoSummary summary = StructureStubInfo::summary(stubInfo);
if (!isInlineable(summary))
return GetByStatus(summary, *stubInfo);
// Finally figure out if we can derive an access strategy.
GetByStatus result;
result.m_state = Simple;
result.m_wasSeenInJIT = true; // This is interesting for bytecode dumping only.
switch (stubInfo->cacheType()) {
case CacheType::Unset:
return GetByStatus(NoInformation);
case CacheType::GetByIdSelf: {
Structure* structure = stubInfo->u.byIdSelf.baseObjectStructure.get();
if (structure->takesSlowPathInDFGForImpureProperty())
return GetByStatus(JSC::slowVersion(summary), *stubInfo);
CacheableIdentifier identifier = stubInfo->getByIdSelfIdentifier();
UniquedStringImpl* uid = identifier.uid();
RELEASE_ASSERT(uid);
GetByIdVariant variant(WTFMove(identifier));
unsigned attributes;
variant.m_offset = structure->getConcurrently(uid, attributes);
if (!isValidOffset(variant.m_offset))
return GetByStatus(JSC::slowVersion(summary), *stubInfo);
if (attributes & PropertyAttribute::CustomAccessorOrValue)
return GetByStatus(JSC::slowVersion(summary), *stubInfo);
variant.m_structureSet.add(structure);
bool didAppend = result.appendVariant(variant);
ASSERT_UNUSED(didAppend, didAppend);
return result;
}
case CacheType::Stub: {
PolymorphicAccess* list = stubInfo->u.stub;
if (list->size() == 1) {
const AccessCase& access = list->at(0);
switch (access.type()) {
case AccessCase::ModuleNamespaceLoad:
return GetByStatus(access.as<ModuleNamespaceAccessCase>());
default:
break;
}
}
for (unsigned listIndex = 0; listIndex < list->size(); ++listIndex) {
const AccessCase& access = list->at(listIndex);
if (access.viaProxy())
return GetByStatus(JSC::slowVersion(summary), *stubInfo);
if (access.usesPolyProto())
return GetByStatus(JSC::slowVersion(summary), *stubInfo);
if (!access.requiresIdentifierNameMatch()) {
// FIXME: We could use this for indexed loads in the future. This is pretty solid profiling
// information, and probably better than ArrayProfile when it's available.
// https://bugs.webkit.org/show_bug.cgi?id=204215
return GetByStatus(JSC::slowVersion(summary), *stubInfo);
}
Structure* structure = access.structure();
if (!structure) {
// The null structure cases arise due to array.length and string.length. We have no way
// of creating a GetByIdVariant for those, and we don't really have to since the DFG
// handles those cases in FixupPhase using value profiling. That's a bit awkward - we
// shouldn't have to use value profiling to discover something that the AccessCase
// could have told us. But, it works well enough. So, our only concern here is to not
// crash on null structure.
return GetByStatus(JSC::slowVersion(summary), *stubInfo);
}
ComplexGetStatus complexGetStatus = ComplexGetStatus::computeFor(
structure, access.conditionSet(), access.uid());
switch (complexGetStatus.kind()) {
case ComplexGetStatus::ShouldSkip:
continue;
case ComplexGetStatus::TakesSlowPath:
return GetByStatus(JSC::slowVersion(summary), *stubInfo);
case ComplexGetStatus::Inlineable: {
std::unique_ptr<CallLinkStatus> callLinkStatus;
JSFunction* intrinsicFunction = nullptr;
FunctionPtr<OperationPtrTag> customAccessorGetter;
std::unique_ptr<DOMAttributeAnnotation> domAttribute;
bool haveDOMAttribute = false;
switch (access.type()) {
case AccessCase::Load:
case AccessCase::GetGetter:
case AccessCase::Miss: {
break;
}
case AccessCase::IntrinsicGetter: {
intrinsicFunction = access.as<IntrinsicGetterAccessCase>().intrinsicFunction();
break;
}
case AccessCase::Getter: {
callLinkStatus = makeUnique<CallLinkStatus>();
if (CallLinkInfo* callLinkInfo = access.as<GetterSetterAccessCase>().callLinkInfo()) {
*callLinkStatus = CallLinkStatus::computeFor(
locker, profiledBlock, *callLinkInfo, callExitSiteData);
}
break;
}
case AccessCase::CustomAccessorGetter: {
customAccessorGetter = access.as<GetterSetterAccessCase>().customAccessor();
if (!access.as<GetterSetterAccessCase>().domAttribute())
return GetByStatus(JSC::slowVersion(summary), *stubInfo);
domAttribute = WTF::makeUnique<DOMAttributeAnnotation>(*access.as<GetterSetterAccessCase>().domAttribute());
haveDOMAttribute = true;
result.m_state = Custom;
break;
}
default: {
// FIXME: It would be totally sweet to support more of these at some point in the
// future. https://bugs.webkit.org/show_bug.cgi?id=133052
return GetByStatus(JSC::slowVersion(summary), *stubInfo);
} }
ASSERT((AccessCase::Miss == access.type() || access.isCustom()) == (access.offset() == invalidOffset));
GetByIdVariant variant(access.identifier(), StructureSet(structure), complexGetStatus.offset(),
complexGetStatus.conditionSet(), WTFMove(callLinkStatus),
intrinsicFunction,
customAccessorGetter,
WTFMove(domAttribute));
if (!result.appendVariant(variant))
return GetByStatus(JSC::slowVersion(summary), *stubInfo);
if (haveDOMAttribute) {
// Give up when custom accesses are not merged into one.
if (result.numVariants() != 1)
return GetByStatus(JSC::slowVersion(summary), *stubInfo);
} else {
// Give up when custom access and simple access are mixed.
if (result.m_state == Custom)
return GetByStatus(JSC::slowVersion(summary), *stubInfo);
}
break;
} }
}
return result;
}
default:
return GetByStatus(JSC::slowVersion(summary), *stubInfo);
}
RELEASE_ASSERT_NOT_REACHED();
return GetByStatus();
}
GetByStatus GetByStatus::computeFor(
CodeBlock* profiledBlock, ICStatusMap& baselineMap,
ICStatusContextStack& icContextStack, CodeOrigin codeOrigin)
{
BytecodeIndex bytecodeIndex = codeOrigin.bytecodeIndex();
CallLinkStatus::ExitSiteData callExitSiteData = CallLinkStatus::computeExitSiteData(profiledBlock, bytecodeIndex);
ExitFlag didExit = hasBadCacheExitSite(profiledBlock, bytecodeIndex);
for (ICStatusContext* context : icContextStack) {
ICStatus status = context->get(codeOrigin);
auto bless = [&] (const GetByStatus& result) -> GetByStatus {
if (!context->isInlined(codeOrigin)) {
// Merge with baseline result, which also happens to contain exit data for both
// inlined and not-inlined.
GetByStatus baselineResult = computeFor(
profiledBlock, baselineMap, bytecodeIndex, didExit,
callExitSiteData);
baselineResult.merge(result);
return baselineResult;
}
if (didExit.isSet(ExitFromInlined))
return result.slowVersion();
return result;
};
if (status.stubInfo) {
GetByStatus result;
{
ConcurrentJSLocker locker(context->optimizedCodeBlock->m_lock);
result = computeForStubInfoWithoutExitSiteFeedback(
locker, context->optimizedCodeBlock, status.stubInfo, callExitSiteData);
}
if (result.isSet())
return bless(result);
}
if (status.getStatus)
return bless(*status.getStatus);
}
return computeFor(profiledBlock, baselineMap, bytecodeIndex, didExit, callExitSiteData);
}
GetByStatus GetByStatus::computeFor(const StructureSet& set, UniquedStringImpl* uid)
{
// For now we only handle the super simple self access case. We could handle the
// prototype case in the future.
//
// Note that this code is also used for GetByIdDirect since this function only looks
// into direct properties. When supporting prototype chains, we should split this for
// GetById and GetByIdDirect.
if (set.isEmpty())
return GetByStatus();
if (parseIndex(*uid))
return GetByStatus(LikelyTakesSlowPath);
GetByStatus result;
result.m_state = Simple;
result.m_wasSeenInJIT = false;
for (unsigned i = 0; i < set.size(); ++i) {
Structure* structure = set[i];
if (structure->typeInfo().overridesGetOwnPropertySlot() && structure->typeInfo().type() != GlobalObjectType)
return GetByStatus(LikelyTakesSlowPath);
if (!structure->propertyAccessesAreCacheable())
return GetByStatus(LikelyTakesSlowPath);
unsigned attributes;
PropertyOffset offset = structure->getConcurrently(uid, attributes);
if (!isValidOffset(offset))
return GetByStatus(LikelyTakesSlowPath); // It's probably a prototype lookup. Give up on life for now, even though we could totally be way smarter about it.
if (attributes & PropertyAttribute::Accessor)
return GetByStatus(MakesCalls); // We could be smarter here, like strength-reducing this to a Call.
if (attributes & PropertyAttribute::CustomAccessorOrValue)
return GetByStatus(LikelyTakesSlowPath);
if (!result.appendVariant(GetByIdVariant(nullptr, structure, offset)))
return GetByStatus(LikelyTakesSlowPath);
}
return result;
}
#endif // ENABLE(JIT)
bool GetByStatus::makesCalls() const
{
switch (m_state) {
case NoInformation:
case LikelyTakesSlowPath:
case ObservedTakesSlowPath:
case Custom:
case ModuleNamespace:
return false;
case Simple:
for (unsigned i = m_variants.size(); i--;) {
if (m_variants[i].callLinkStatus())
return true;
}
return false;
case MakesCalls:
case ObservedSlowPathAndMakesCalls:
return true;
}
RELEASE_ASSERT_NOT_REACHED();
return false;
}
GetByStatus GetByStatus::slowVersion() const
{
if (observedStructureStubInfoSlowPath())
return GetByStatus(makesCalls() ? ObservedSlowPathAndMakesCalls : ObservedTakesSlowPath, wasSeenInJIT());
return GetByStatus(makesCalls() ? MakesCalls : LikelyTakesSlowPath, wasSeenInJIT());
}
void GetByStatus::merge(const GetByStatus& other)
{
if (other.m_state == NoInformation)
return;
auto mergeSlow = [&] () {
if (observedStructureStubInfoSlowPath() || other.observedStructureStubInfoSlowPath())
*this = GetByStatus((makesCalls() || other.makesCalls()) ? ObservedSlowPathAndMakesCalls : ObservedTakesSlowPath);
else
*this = GetByStatus((makesCalls() || other.makesCalls()) ? MakesCalls : LikelyTakesSlowPath);
};
switch (m_state) {
case NoInformation:
*this = other;
return;
case Simple:
case Custom:
if (m_state != other.m_state)
return mergeSlow();
for (const GetByIdVariant& otherVariant : other.m_variants) {
if (!appendVariant(otherVariant))
return mergeSlow();
}
return;
case ModuleNamespace:
if (other.m_state != ModuleNamespace)
return mergeSlow();
if (m_moduleNamespaceData->m_moduleNamespaceObject != other.m_moduleNamespaceData->m_moduleNamespaceObject)
return mergeSlow();
if (m_moduleNamespaceData->m_moduleEnvironment != other.m_moduleNamespaceData->m_moduleEnvironment)
return mergeSlow();
if (m_moduleNamespaceData->m_scopeOffset != other.m_moduleNamespaceData->m_scopeOffset)
return mergeSlow();
return;
case LikelyTakesSlowPath:
case ObservedTakesSlowPath:
case MakesCalls:
case ObservedSlowPathAndMakesCalls:
return mergeSlow();
}
RELEASE_ASSERT_NOT_REACHED();
}
void GetByStatus::filter(const StructureSet& set)
{
if (m_state != Simple)
return;
filterICStatusVariants(m_variants, set);
if (m_variants.isEmpty())
m_state = NoInformation;
}
void GetByStatus::visitAggregate(SlotVisitor& visitor)
{
if (isModuleNamespace())
m_moduleNamespaceData->m_identifier.visitAggregate(visitor);
for (GetByIdVariant& variant : m_variants)
variant.visitAggregate(visitor);
}
void GetByStatus::markIfCheap(SlotVisitor& visitor)
{
for (GetByIdVariant& variant : m_variants)
variant.markIfCheap(visitor);
}
bool GetByStatus::finalize(VM& vm)
{
for (GetByIdVariant& variant : m_variants) {
if (!variant.finalize(vm))
return false;
}
if (isModuleNamespace()) {
if (m_moduleNamespaceData->m_moduleNamespaceObject && !vm.heap.isMarked(m_moduleNamespaceData->m_moduleNamespaceObject))
return false;
if (m_moduleNamespaceData->m_moduleEnvironment && !vm.heap.isMarked(m_moduleNamespaceData->m_moduleEnvironment))
return false;
}
return true;
}
CacheableIdentifier GetByStatus::singleIdentifier() const
{
if (isModuleNamespace())
return m_moduleNamespaceData->m_identifier;
if (m_variants.isEmpty())
return nullptr;
CacheableIdentifier result = m_variants.first().identifier();
if (!result)
return nullptr;
for (size_t i = 1; i < m_variants.size(); ++i) {
CacheableIdentifier identifier = m_variants[i].identifier();
if (!identifier)
return nullptr;
if (identifier != result)
return nullptr;
}
return result;
}
void GetByStatus::dump(PrintStream& out) const
{
out.print("(");
switch (m_state) {
case NoInformation:
out.print("NoInformation");
break;
case Simple:
out.print("Simple");
break;
case Custom:
out.print("Custom");
break;
case ModuleNamespace:
out.print("ModuleNamespace");
break;
case LikelyTakesSlowPath:
out.print("LikelyTakesSlowPath");
break;
case ObservedTakesSlowPath:
out.print("ObservedTakesSlowPath");
break;
case MakesCalls:
out.print("MakesCalls");
break;
case ObservedSlowPathAndMakesCalls:
out.print("ObservedSlowPathAndMakesCalls");
break;
}
out.print(", ", listDump(m_variants), ", seenInJIT = ", m_wasSeenInJIT, ")");
}
} // namespace JSC