GetByIdStatus GetByIdStatus::computeFor(
CodeBlock* profiledBlock, CodeBlock* dfgBlock, StubInfoMap& baselineMap,
StubInfoMap& dfgMap, CodeOrigin codeOrigin, StringImpl* uid)
{
#if ENABLE(DFG_JIT)
if (dfgBlock) {
GetByIdStatus result;
{
ConcurrentJITLocker locker(dfgBlock->m_lock);
result = computeForStubInfo(locker, dfgBlock, dfgMap.get(codeOrigin), uid);
}
if (result.takesSlowPath())
return result;
{
ConcurrentJITLocker locker(profiledBlock->m_lock);
if (hasExitSite(locker, profiledBlock, codeOrigin.bytecodeIndex, ExitFromFTL))
return GetByIdStatus(TakesSlowPath, true);
}
if (result.isSet())
return result;
}
#else
UNUSED_PARAM(dfgBlock);
UNUSED_PARAM(dfgMap);
#endif
return computeFor(profiledBlock, baselineMap, codeOrigin.bytecodeIndex, uid);
}
GetByIdStatus GetByIdStatus::computeFor(const StructureSet& set, StringImpl* uid)
{
// For now we only handle the super simple self access case. We could handle the
// prototype case in the future.
if (set.isEmpty())
return GetByIdStatus();
if (toUInt32FromStringImpl(uid) != PropertyName::NotAnIndex)
return GetByIdStatus(TakesSlowPath);
GetByIdStatus 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 GetByIdStatus(TakesSlowPath);
if (!structure->propertyAccessesAreCacheable())
return GetByIdStatus(TakesSlowPath);
unsigned attributes;
PropertyOffset offset = structure->getConcurrently(uid, attributes);
if (!isValidOffset(offset))
return GetByIdStatus(TakesSlowPath); // It's probably a prototype lookup. Give up on life for now, even though we could totally be way smarter about it.
if (attributes & Accessor)
return GetByIdStatus(MakesCalls); // We could be smarter here, like strenght-reducing this to a Call.
if (!result.appendVariant(GetByIdVariant(structure, offset)))
return GetByIdStatus(TakesSlowPath);
}
return result;
}
GetByIdStatus GetByIdStatus::computeForStubInfo(const ConcurrentJITLocker& locker, CodeBlock* profiledBlock, StructureStubInfo* stubInfo, CodeOrigin codeOrigin, UniquedStringImpl* uid)
{
GetByIdStatus result = GetByIdStatus::computeForStubInfoWithoutExitSiteFeedback(
locker, profiledBlock, stubInfo, uid,
CallLinkStatus::computeExitSiteData(locker, profiledBlock, codeOrigin.bytecodeIndex));
if (!result.takesSlowPath() && GetByIdStatus::hasExitSite(locker, profiledBlock, codeOrigin.bytecodeIndex))
return GetByIdStatus(result.makesCalls() ? GetByIdStatus::MakesCalls : GetByIdStatus::TakesSlowPath, true);
return result;
}
GetByIdStatus GetByIdStatus::computeFor(
CodeBlock* profiledBlock, CodeBlock* dfgBlock, StubInfoMap& baselineMap,
StubInfoMap& dfgMap, CodeOrigin codeOrigin, UniquedStringImpl* uid)
{
#if ENABLE(DFG_JIT)
if (dfgBlock) {
CallLinkStatus::ExitSiteData exitSiteData;
{
ConcurrentJITLocker locker(profiledBlock->m_lock);
exitSiteData = CallLinkStatus::computeExitSiteData(
locker, profiledBlock, codeOrigin.bytecodeIndex);
}
GetByIdStatus result;
{
ConcurrentJITLocker locker(dfgBlock->m_lock);
result = computeForStubInfoWithoutExitSiteFeedback(
locker, dfgBlock, dfgMap.get(codeOrigin), uid, exitSiteData);
}
if (result.takesSlowPath())
return result;
{
ConcurrentJITLocker locker(profiledBlock->m_lock);
if (hasExitSite(locker, profiledBlock, codeOrigin.bytecodeIndex))
return GetByIdStatus(TakesSlowPath, true);
}
if (result.isSet())
return result;
}
#else
UNUSED_PARAM(dfgBlock);
UNUSED_PARAM(dfgMap);
#endif
return computeFor(profiledBlock, baselineMap, codeOrigin.bytecodeIndex, uid);
}
GetByIdStatus GetByIdStatus::computeFor(CodeBlock* profiledBlock, StubInfoMap& map, unsigned bytecodeIndex, UniquedStringImpl* uid)
{
ConcurrentJITLocker locker(profiledBlock->m_lock);
GetByIdStatus result;
#if ENABLE(DFG_JIT)
result = computeForStubInfoWithoutExitSiteFeedback(
locker, profiledBlock, map.get(CodeOrigin(bytecodeIndex)), uid,
CallLinkStatus::computeExitSiteData(locker, profiledBlock, bytecodeIndex));
if (!result.takesSlowPath()
&& hasExitSite(locker, profiledBlock, bytecodeIndex))
return GetByIdStatus(result.makesCalls() ? MakesCalls : TakesSlowPath, true);
#else
UNUSED_PARAM(map);
#endif
if (!result)
return computeFromLLInt(profiledBlock, bytecodeIndex, uid);
return result;
}
GetByIdStatus GetByIdStatus::computeFor(CodeBlock* profiledBlock, StubInfoMap& map, unsigned bytecodeIndex, StringImpl* uid)
{
ConcurrentJITLocker locker(profiledBlock->m_lock);
GetByIdStatus result;
#if ENABLE(DFG_JIT)
result = computeForStubInfo(
locker, profiledBlock, map.get(CodeOrigin(bytecodeIndex)), uid);
if (!result.takesSlowPath()
&& (hasExitSite(locker, profiledBlock, bytecodeIndex)
|| profiledBlock->likelyToTakeSlowCase(bytecodeIndex)))
return GetByIdStatus(TakesSlowPath, true);
#else
UNUSED_PARAM(map);
#endif
if (!result)
return computeFromLLInt(profiledBlock, bytecodeIndex, uid);
return result;
}
bool foldConstants(BasicBlock* block)
{
bool changed = false;
m_state.beginBasicBlock(block);
for (unsigned indexInBlock = 0; indexInBlock < block->size(); ++indexInBlock) {
if (!m_state.isValid())
break;
Node* node = block->at(indexInBlock);
bool alreadyHandled = false;
bool eliminated = false;
switch (node->op()) {
case BooleanToNumber: {
if (node->child1().useKind() == UntypedUse
&& !m_interpreter.needsTypeCheck(node->child1(), SpecBoolean))
node->child1().setUseKind(BooleanUse);
break;
}
case CheckArgumentsNotCreated: {
if (!isEmptySpeculation(
m_state.variables().operand(
m_graph.argumentsRegisterFor(node->origin.semantic)).m_type))
break;
node->convertToPhantom();
eliminated = true;
break;
}
case CheckStructure:
case ArrayifyToStructure: {
AbstractValue& value = m_state.forNode(node->child1());
StructureSet set;
if (node->op() == ArrayifyToStructure)
set = node->structure();
else
set = node->structureSet();
if (value.m_structure.isSubsetOf(set)) {
m_interpreter.execute(indexInBlock); // Catch the fact that we may filter on cell.
node->convertToPhantom();
eliminated = true;
break;
}
break;
}
case CheckArray:
case Arrayify: {
if (!node->arrayMode().alreadyChecked(m_graph, node, m_state.forNode(node->child1())))
break;
node->convertToPhantom();
eliminated = true;
break;
}
case PutStructure: {
if (m_state.forNode(node->child1()).m_structure.onlyStructure() != node->transition()->next)
break;
node->convertToPhantom();
eliminated = true;
break;
}
case CheckFunction: {
if (m_state.forNode(node->child1()).value() != node->function()->value())
break;
node->convertToPhantom();
eliminated = true;
break;
}
case CheckInBounds: {
JSValue left = m_state.forNode(node->child1()).value();
JSValue right = m_state.forNode(node->child2()).value();
if (left && right && left.isInt32() && right.isInt32()
&& static_cast<uint32_t>(left.asInt32()) < static_cast<uint32_t>(right.asInt32())) {
node->convertToPhantom();
eliminated = true;
break;
}
break;
}
case MultiGetByOffset: {
Edge baseEdge = node->child1();
Node* base = baseEdge.node();
MultiGetByOffsetData& data = node->multiGetByOffsetData();
// First prune the variants, then check if the MultiGetByOffset can be
// strength-reduced to a GetByOffset.
AbstractValue baseValue = m_state.forNode(base);
m_interpreter.execute(indexInBlock); // Push CFA over this node after we get the state before.
alreadyHandled = true; // Don't allow the default constant folder to do things to this.
for (unsigned i = 0; i < data.variants.size(); ++i) {
GetByIdVariant& variant = data.variants[i];
variant.structureSet().filter(baseValue);
if (variant.structureSet().isEmpty()) {
data.variants[i--] = data.variants.last();
data.variants.removeLast();
changed = true;
}
}
if (data.variants.size() != 1)
break;
emitGetByOffset(
indexInBlock, node, baseValue, data.variants[0], data.identifierNumber);
changed = true;
break;
}
case MultiPutByOffset: {
Edge baseEdge = node->child1();
Node* base = baseEdge.node();
MultiPutByOffsetData& data = node->multiPutByOffsetData();
AbstractValue baseValue = m_state.forNode(base);
m_interpreter.execute(indexInBlock); // Push CFA over this node after we get the state before.
alreadyHandled = true; // Don't allow the default constant folder to do things to this.
for (unsigned i = 0; i < data.variants.size(); ++i) {
PutByIdVariant& variant = data.variants[i];
variant.oldStructure().filter(baseValue);
if (variant.oldStructure().isEmpty()) {
data.variants[i--] = data.variants.last();
data.variants.removeLast();
changed = true;
continue;
}
if (variant.kind() == PutByIdVariant::Transition
&& variant.oldStructure().onlyStructure() == variant.newStructure()) {
variant = PutByIdVariant::replace(
variant.oldStructure(),
variant.offset());
changed = true;
}
}
if (data.variants.size() != 1)
break;
emitPutByOffset(
indexInBlock, node, baseValue, data.variants[0], data.identifierNumber);
changed = true;
break;
}
case GetById:
case GetByIdFlush: {
Edge childEdge = node->child1();
Node* child = childEdge.node();
unsigned identifierNumber = node->identifierNumber();
AbstractValue baseValue = m_state.forNode(child);
m_interpreter.execute(indexInBlock); // Push CFA over this node after we get the state before.
alreadyHandled = true; // Don't allow the default constant folder to do things to this.
if (baseValue.m_structure.isTop() || baseValue.m_structure.isClobbered()
|| (node->child1().useKind() == UntypedUse || (baseValue.m_type & ~SpecCell)))
break;
GetByIdStatus status = GetByIdStatus::computeFor(
vm(), baseValue.m_structure.set(), m_graph.identifiers()[identifierNumber]);
if (!status.isSimple())
break;
for (unsigned i = status.numVariants(); i--;) {
if (!status[i].constantChecks().isEmpty()
|| status[i].alternateBase()) {
// FIXME: We could handle prototype cases.
// https://bugs.webkit.org/show_bug.cgi?id=110386
break;
}
}
if (status.numVariants() == 1) {
emitGetByOffset(indexInBlock, node, baseValue, status[0], identifierNumber);
changed = true;
break;
}
if (!isFTL(m_graph.m_plan.mode))
break;
MultiGetByOffsetData* data = m_graph.m_multiGetByOffsetData.add();
data->variants = status.variants();
data->identifierNumber = identifierNumber;
node->convertToMultiGetByOffset(data);
changed = true;
break;
}
case PutById:
case PutByIdDirect:
case PutByIdFlush: {
NodeOrigin origin = node->origin;
Edge childEdge = node->child1();
Node* child = childEdge.node();
unsigned identifierNumber = node->identifierNumber();
ASSERT(childEdge.useKind() == CellUse);
AbstractValue baseValue = m_state.forNode(child);
m_interpreter.execute(indexInBlock); // Push CFA over this node after we get the state before.
alreadyHandled = true; // Don't allow the default constant folder to do things to this.
if (baseValue.m_structure.isTop() || baseValue.m_structure.isClobbered())
break;
PutByIdStatus status = PutByIdStatus::computeFor(
vm(),
m_graph.globalObjectFor(origin.semantic),
baseValue.m_structure.set(),
m_graph.identifiers()[identifierNumber],
node->op() == PutByIdDirect);
if (!status.isSimple())
break;
ASSERT(status.numVariants());
if (status.numVariants() > 1 && !isFTL(m_graph.m_plan.mode))
break;
changed = true;
for (unsigned i = status.numVariants(); i--;)
addChecks(origin, indexInBlock, status[i].constantChecks());
if (status.numVariants() == 1) {
emitPutByOffset(indexInBlock, node, baseValue, status[0], identifierNumber);
break;
}
ASSERT(isFTL(m_graph.m_plan.mode));
MultiPutByOffsetData* data = m_graph.m_multiPutByOffsetData.add();
data->variants = status.variants();
data->identifierNumber = identifierNumber;
node->convertToMultiPutByOffset(data);
break;
}
case ToPrimitive: {
if (m_state.forNode(node->child1()).m_type & ~(SpecFullNumber | SpecBoolean | SpecString))
break;
node->convertToIdentity();
changed = true;
break;
}
case GetMyArgumentByVal: {
InlineCallFrame* inlineCallFrame = node->origin.semantic.inlineCallFrame;
JSValue value = m_state.forNode(node->child1()).m_value;
if (inlineCallFrame && value && value.isInt32()) {
int32_t index = value.asInt32();
if (index >= 0
&& static_cast<size_t>(index + 1) < inlineCallFrame->arguments.size()) {
// Roll the interpreter over this.
m_interpreter.execute(indexInBlock);
eliminated = true;
int operand =
inlineCallFrame->stackOffset +
m_graph.baselineCodeBlockFor(inlineCallFrame)->argumentIndexAfterCapture(index);
m_insertionSet.insertNode(
indexInBlock, SpecNone, CheckArgumentsNotCreated, node->origin);
m_insertionSet.insertNode(
indexInBlock, SpecNone, Phantom, node->origin, node->children);
node->convertToGetLocalUnlinked(VirtualRegister(operand));
break;
}
}
break;
}
case Check: {
alreadyHandled = true;
m_interpreter.execute(indexInBlock);
for (unsigned i = 0; i < AdjacencyList::Size; ++i) {
Edge edge = node->children.child(i);
if (!edge)
break;
if (edge.isProved() || edge.willNotHaveCheck()) {
node->children.removeEdge(i--);
changed = true;
}
}
break;
}
default:
break;
}
if (eliminated) {
changed = true;
continue;
}
if (alreadyHandled)
continue;
m_interpreter.execute(indexInBlock);
if (!m_state.isValid()) {
// If we invalidated then we shouldn't attempt to constant-fold. Here's an
// example:
//
// c: JSConstant(4.2)
// x: ValueToInt32(Check:Int32:@const)
//
// It would be correct for an analysis to assume that execution cannot
// proceed past @x. Therefore, constant-folding @x could be rather bad. But,
// the CFA may report that it found a constant even though it also reported
// that everything has been invalidated. This will only happen in a couple of
// the constant folding cases; most of them are also separately defensive
// about such things.
break;
}
if (!node->shouldGenerate() || m_state.didClobber() || node->hasConstant())
continue;
// Interesting fact: this freezing that we do right here may turn an fragile value into
// a weak value. See DFGValueStrength.h.
FrozenValue* value = m_graph.freeze(m_state.forNode(node).value());
if (!*value)
continue;
NodeOrigin origin = node->origin;
AdjacencyList children = node->children;
m_graph.convertToConstant(node, value);
if (!children.isEmpty()) {
m_insertionSet.insertNode(
indexInBlock, SpecNone, Phantom, origin, children);
}
changed = true;
}
m_state.reset();
m_insertionSet.execute(block);
return changed;
}
bool foldConstants(BasicBlock* block)
{
bool changed = false;
m_state.beginBasicBlock(block);
for (unsigned indexInBlock = 0; indexInBlock < block->size(); ++indexInBlock) {
if (!m_state.isValid())
break;
Node* node = block->at(indexInBlock);
bool eliminated = false;
switch (node->op()) {
case BooleanToNumber: {
if (node->child1().useKind() == UntypedUse
&& !m_interpreter.needsTypeCheck(node->child1(), SpecBoolean))
node->child1().setUseKind(BooleanUse);
break;
}
case CheckArgumentsNotCreated: {
if (!isEmptySpeculation(
m_state.variables().operand(
m_graph.argumentsRegisterFor(node->origin.semantic)).m_type))
break;
node->convertToPhantom();
eliminated = true;
break;
}
case CheckStructure:
case ArrayifyToStructure: {
AbstractValue& value = m_state.forNode(node->child1());
StructureSet set;
if (node->op() == ArrayifyToStructure)
set = node->structure();
else
set = node->structureSet();
if (value.m_currentKnownStructure.isSubsetOf(set)) {
m_interpreter.execute(indexInBlock); // Catch the fact that we may filter on cell.
node->convertToPhantom();
eliminated = true;
break;
}
StructureAbstractValue& structureValue = value.m_futurePossibleStructure;
if (structureValue.isSubsetOf(set)
&& structureValue.hasSingleton()) {
Structure* structure = structureValue.singleton();
m_interpreter.execute(indexInBlock); // Catch the fact that we may filter on cell.
AdjacencyList children = node->children;
children.removeEdge(0);
if (!!children.child1())
m_insertionSet.insertNode(indexInBlock, SpecNone, Phantom, node->origin, children);
node->children.setChild2(Edge());
node->children.setChild3(Edge());
node->convertToStructureTransitionWatchpoint(structure);
eliminated = true;
break;
}
break;
}
case CheckArray:
case Arrayify: {
if (!node->arrayMode().alreadyChecked(m_graph, node, m_state.forNode(node->child1())))
break;
node->convertToPhantom();
eliminated = true;
break;
}
case CheckFunction: {
if (m_state.forNode(node->child1()).value() != node->function())
break;
node->convertToPhantom();
eliminated = true;
break;
}
case CheckInBounds: {
JSValue left = m_state.forNode(node->child1()).value();
JSValue right = m_state.forNode(node->child2()).value();
if (left && right && left.isInt32() && right.isInt32()
&& static_cast<uint32_t>(left.asInt32()) < static_cast<uint32_t>(right.asInt32())) {
node->convertToPhantom();
eliminated = true;
break;
}
break;
}
case MultiGetByOffset: {
Edge childEdge = node->child1();
Node* child = childEdge.node();
MultiGetByOffsetData& data = node->multiGetByOffsetData();
Structure* structure = m_state.forNode(child).bestProvenStructure();
if (!structure)
break;
for (unsigned i = data.variants.size(); i--;) {
const GetByIdVariant& variant = data.variants[i];
if (!variant.structureSet().contains(structure))
continue;
if (variant.chain())
break;
emitGetByOffset(indexInBlock, node, structure, variant, data.identifierNumber);
eliminated = true;
break;
}
break;
}
case MultiPutByOffset: {
Edge childEdge = node->child1();
Node* child = childEdge.node();
MultiPutByOffsetData& data = node->multiPutByOffsetData();
Structure* structure = m_state.forNode(child).bestProvenStructure();
if (!structure)
break;
for (unsigned i = data.variants.size(); i--;) {
const PutByIdVariant& variant = data.variants[i];
if (variant.oldStructure() != structure)
continue;
emitPutByOffset(indexInBlock, node, structure, variant, data.identifierNumber);
eliminated = true;
break;
}
break;
}
case GetById:
case GetByIdFlush: {
Edge childEdge = node->child1();
Node* child = childEdge.node();
unsigned identifierNumber = node->identifierNumber();
if (childEdge.useKind() != CellUse)
break;
Structure* structure = m_state.forNode(child).bestProvenStructure();
if (!structure)
break;
GetByIdStatus status = GetByIdStatus::computeFor(
vm(), structure, m_graph.identifiers()[identifierNumber]);
if (!status.isSimple() || status.numVariants() != 1) {
// FIXME: We could handle prototype cases.
// https://bugs.webkit.org/show_bug.cgi?id=110386
break;
}
emitGetByOffset(indexInBlock, node, structure, status[0], identifierNumber);
eliminated = true;
break;
}
case PutById:
case PutByIdDirect: {
NodeOrigin origin = node->origin;
Edge childEdge = node->child1();
Node* child = childEdge.node();
unsigned identifierNumber = node->identifierNumber();
ASSERT(childEdge.useKind() == CellUse);
Structure* structure = m_state.forNode(child).bestProvenStructure();
if (!structure)
break;
PutByIdStatus status = PutByIdStatus::computeFor(
vm(),
m_graph.globalObjectFor(origin.semantic),
structure,
m_graph.identifiers()[identifierNumber],
node->op() == PutByIdDirect);
if (!status.isSimple())
break;
if (status.numVariants() != 1)
break;
emitPutByOffset(indexInBlock, node, structure, status[0], identifierNumber);
eliminated = true;
break;
}
case ToPrimitive: {
if (m_state.forNode(node->child1()).m_type & ~(SpecFullNumber | SpecBoolean | SpecString))
break;
node->convertToIdentity();
break;
}
default:
break;
}
if (eliminated) {
changed = true;
continue;
}
m_interpreter.execute(indexInBlock);
if (!m_state.isValid()) {
// If we invalidated then we shouldn't attempt to constant-fold. Here's an
// example:
//
// c: JSConstant(4.2)
// x: ValueToInt32(Check:Int32:@const)
//
// It would be correct for an analysis to assume that execution cannot
// proceed past @x. Therefore, constant-folding @x could be rather bad. But,
// the CFA may report that it found a constant even though it also reported
// that everything has been invalidated. This will only happen in a couple of
// the constant folding cases; most of them are also separately defensive
// about such things.
break;
}
if (!node->shouldGenerate() || m_state.didClobber() || node->hasConstant())
continue;
JSValue value = m_state.forNode(node).value();
if (!value)
continue;
// Check if merging the abstract value of the constant into the abstract value
// we've proven for this node wouldn't widen the proof. If it widens the proof
// (i.e. says that the set contains more things in it than it previously did)
// then we refuse to fold.
AbstractValue oldValue = m_state.forNode(node);
AbstractValue constantValue;
constantValue.set(m_graph, value);
constantValue.fixTypeForRepresentation(node);
if (oldValue.merge(constantValue))
continue;
NodeOrigin origin = node->origin;
AdjacencyList children = node->children;
if (node->op() == GetLocal)
m_graph.dethread();
else
ASSERT(!node->hasVariableAccessData(m_graph));
m_graph.convertToConstant(node, value);
m_insertionSet.insertNode(
indexInBlock, SpecNone, Phantom, origin, children);
changed = true;
}
m_state.reset();
m_insertionSet.execute(block);
return changed;
}
GetByIdStatus GetByIdStatus::computeForStubInfo(
const ConcurrentJITLocker& locker, CodeBlock* profiledBlock, StructureStubInfo* stubInfo, StringImpl* uid,
CallLinkStatus::ExitSiteData callExitSiteData)
{
if (!stubInfo || !stubInfo->seen)
return GetByIdStatus(NoInformation);
PolymorphicGetByIdList* list = 0;
State slowPathState = TakesSlowPath;
if (stubInfo->accessType == access_get_by_id_list) {
list = stubInfo->u.getByIdList.list;
for (unsigned i = 0; i < list->size(); ++i) {
const GetByIdAccess& access = list->at(i);
if (access.doesCalls())
slowPathState = MakesCalls;
}
}
// Finally figure out if we can derive an access strategy.
GetByIdStatus result;
result.m_state = Simple;
result.m_wasSeenInJIT = true; // This is interesting for bytecode dumping only.
switch (stubInfo->accessType) {
case access_unset:
return GetByIdStatus(NoInformation);
case access_get_by_id_self: {
Structure* structure = stubInfo->u.getByIdSelf.baseObjectStructure.get();
if (structure->takesSlowPathInDFGForImpureProperty())
return GetByIdStatus(slowPathState, true);
unsigned attributesIgnored;
GetByIdVariant variant;
variant.m_offset = structure->getConcurrently(uid, attributesIgnored);
if (!isValidOffset(variant.m_offset))
return GetByIdStatus(slowPathState, true);
variant.m_structureSet.add(structure);
bool didAppend = result.appendVariant(variant);
ASSERT_UNUSED(didAppend, didAppend);
return result;
}
case access_get_by_id_list: {
for (unsigned listIndex = 0; listIndex < list->size(); ++listIndex) {
Structure* structure = list->at(listIndex).structure();
ComplexGetStatus complexGetStatus = ComplexGetStatus::computeFor(
profiledBlock, structure, list->at(listIndex).chain(),
list->at(listIndex).chainCount(), uid);
switch (complexGetStatus.kind()) {
case ComplexGetStatus::ShouldSkip:
continue;
case ComplexGetStatus::TakesSlowPath:
return GetByIdStatus(slowPathState, true);
case ComplexGetStatus::Inlineable: {
std::unique_ptr<CallLinkStatus> callLinkStatus;
switch (list->at(listIndex).type()) {
case GetByIdAccess::SimpleInline:
case GetByIdAccess::SimpleStub: {
break;
}
case GetByIdAccess::Getter: {
AccessorCallJITStubRoutine* stub = static_cast<AccessorCallJITStubRoutine*>(
list->at(listIndex).stubRoutine());
callLinkStatus = std::make_unique<CallLinkStatus>(
CallLinkStatus::computeFor(
locker, profiledBlock, *stub->m_callLinkInfo, callExitSiteData));
break;
}
case GetByIdAccess::CustomGetter:
case GetByIdAccess::WatchedStub:{
// FIXME: It would be totally sweet to support this at some point in the future.
// https://bugs.webkit.org/show_bug.cgi?id=133052
return GetByIdStatus(slowPathState, true);
}
default:
RELEASE_ASSERT_NOT_REACHED();
}
GetByIdVariant variant(
StructureSet(structure), complexGetStatus.offset(), complexGetStatus.chain(),
std::move(callLinkStatus));
if (!result.appendVariant(variant))
return GetByIdStatus(slowPathState, true);
break;
} }
}
return result;
}
default:
return GetByIdStatus(slowPathState, true);
}
RELEASE_ASSERT_NOT_REACHED();
return GetByIdStatus();
}
GetByIdStatus GetByIdStatus::computeForStubInfoWithoutExitSiteFeedback(
const ConcurrentJITLocker& locker, CodeBlock* profiledBlock, StructureStubInfo* stubInfo, UniquedStringImpl* uid,
CallLinkStatus::ExitSiteData callExitSiteData)
{
if (!stubInfo || !stubInfo->everConsidered)
return GetByIdStatus(NoInformation);
PolymorphicAccess* list = 0;
State slowPathState = TakesSlowPath;
if (stubInfo->cacheType == CacheType::Stub) {
list = stubInfo->u.stub;
for (unsigned i = 0; i < list->size(); ++i) {
const AccessCase& access = list->at(i);
if (access.doesCalls())
slowPathState = MakesCalls;
}
}
if (stubInfo->tookSlowPath)
return GetByIdStatus(slowPathState);
// Finally figure out if we can derive an access strategy.
GetByIdStatus result;
result.m_state = Simple;
result.m_wasSeenInJIT = true; // This is interesting for bytecode dumping only.
switch (stubInfo->cacheType) {
case CacheType::Unset:
return GetByIdStatus(NoInformation);
case CacheType::GetByIdSelf: {
Structure* structure = stubInfo->u.byIdSelf.baseObjectStructure.get();
if (structure->takesSlowPathInDFGForImpureProperty())
return GetByIdStatus(slowPathState, true);
unsigned attributesIgnored;
GetByIdVariant variant;
variant.m_offset = structure->getConcurrently(uid, attributesIgnored);
if (!isValidOffset(variant.m_offset))
return GetByIdStatus(slowPathState, true);
variant.m_structureSet.add(structure);
bool didAppend = result.appendVariant(variant);
ASSERT_UNUSED(didAppend, didAppend);
return result;
}
case CacheType::Stub: {
for (unsigned listIndex = 0; listIndex < list->size(); ++listIndex) {
const AccessCase& access = list->at(listIndex);
if (access.viaProxy())
return GetByIdStatus(slowPathState, true);
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 GetByIdStatus(slowPathState, true);
}
ComplexGetStatus complexGetStatus = ComplexGetStatus::computeFor(
structure, access.conditionSet(), uid);
switch (complexGetStatus.kind()) {
case ComplexGetStatus::ShouldSkip:
continue;
case ComplexGetStatus::TakesSlowPath:
return GetByIdStatus(slowPathState, true);
case ComplexGetStatus::Inlineable: {
std::unique_ptr<CallLinkStatus> callLinkStatus;
JSFunction* intrinsicFunction = nullptr;
switch (access.type()) {
case AccessCase::Load: {
break;
}
case AccessCase::IntrinsicGetter: {
intrinsicFunction = access.intrinsicFunction();
break;
}
case AccessCase::Getter: {
CallLinkInfo* callLinkInfo = access.callLinkInfo();
ASSERT(callLinkInfo);
callLinkStatus = std::make_unique<CallLinkStatus>(
CallLinkStatus::computeFor(
locker, profiledBlock, *callLinkInfo, callExitSiteData));
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 GetByIdStatus(slowPathState, true);
} }
GetByIdVariant variant(
StructureSet(structure), complexGetStatus.offset(),
complexGetStatus.conditionSet(), WTFMove(callLinkStatus),
intrinsicFunction);
if (!result.appendVariant(variant))
return GetByIdStatus(slowPathState, true);
break;
} }
}
return result;
}
default:
return GetByIdStatus(slowPathState, true);
}
RELEASE_ASSERT_NOT_REACHED();
return GetByIdStatus();
}
GetByIdStatus GetByIdStatus::computeForStubInfo(
const ConcurrentJITLocker&, CodeBlock* profiledBlock, StructureStubInfo* stubInfo,
StringImpl* uid)
{
if (!stubInfo || !stubInfo->seen)
return GetByIdStatus(NoInformation);
if (stubInfo->resetByGC)
return GetByIdStatus(TakesSlowPath, true);
PolymorphicGetByIdList* list = 0;
if (stubInfo->accessType == access_get_by_id_list) {
list = stubInfo->u.getByIdList.list;
for (unsigned i = 0; i < list->size(); ++i) {
if (list->at(i).doesCalls())
return GetByIdStatus(MakesCalls, true);
}
}
// Finally figure out if we can derive an access strategy.
GetByIdStatus result;
result.m_state = Simple;
result.m_wasSeenInJIT = true; // This is interesting for bytecode dumping only.
switch (stubInfo->accessType) {
case access_unset:
return GetByIdStatus(NoInformation);
case access_get_by_id_self: {
Structure* structure = stubInfo->u.getByIdSelf.baseObjectStructure.get();
if (structure->takesSlowPathInDFGForImpureProperty())
return GetByIdStatus(TakesSlowPath, true);
unsigned attributesIgnored;
JSCell* specificValue;
GetByIdVariant variant;
variant.m_offset = structure->getConcurrently(
*profiledBlock->vm(), uid, attributesIgnored, specificValue);
if (!isValidOffset(variant.m_offset))
return GetByIdStatus(TakesSlowPath, true);
if (structure->isDictionary())
specificValue = 0;
variant.m_structureSet.add(structure);
variant.m_specificValue = JSValue(specificValue);
result.appendVariant(variant);
return result;
}
case access_get_by_id_list: {
for (unsigned listIndex = 0; listIndex < list->size(); ++listIndex) {
ASSERT(!list->at(listIndex).doesCalls());
Structure* structure = list->at(listIndex).structure();
if (structure->takesSlowPathInDFGForImpureProperty())
return GetByIdStatus(TakesSlowPath, true);
if (list->at(listIndex).chain()) {
RefPtr<IntendedStructureChain> chain = adoptRef(new IntendedStructureChain(
profiledBlock, structure, list->at(listIndex).chain(),
list->at(listIndex).chainCount()));
if (!result.computeForChain(profiledBlock, uid, chain))
return GetByIdStatus(TakesSlowPath, true);
continue;
}
unsigned attributesIgnored;
JSCell* specificValue;
PropertyOffset myOffset = structure->getConcurrently(
*profiledBlock->vm(), uid, attributesIgnored, specificValue);
if (structure->isDictionary())
specificValue = 0;
if (!isValidOffset(myOffset))
return GetByIdStatus(TakesSlowPath, true);
bool found = false;
for (unsigned variantIndex = 0; variantIndex < result.m_variants.size(); ++variantIndex) {
GetByIdVariant& variant = result.m_variants[variantIndex];
if (variant.m_chain)
continue;
if (variant.m_offset != myOffset)
continue;
found = true;
if (variant.m_structureSet.contains(structure))
break;
if (variant.m_specificValue != JSValue(specificValue))
variant.m_specificValue = JSValue();
variant.m_structureSet.add(structure);
break;
}
if (found)
continue;
if (!result.appendVariant(GetByIdVariant(StructureSet(structure), myOffset, specificValue)))
return GetByIdStatus(TakesSlowPath, true);
}
return result;
}
case access_get_by_id_chain: {
if (!stubInfo->u.getByIdChain.isDirect)
return GetByIdStatus(MakesCalls, true);
RefPtr<IntendedStructureChain> chain = adoptRef(new IntendedStructureChain(
profiledBlock,
stubInfo->u.getByIdChain.baseObjectStructure.get(),
stubInfo->u.getByIdChain.chain.get(),
stubInfo->u.getByIdChain.count));
if (result.computeForChain(profiledBlock, uid, chain))
return result;
return GetByIdStatus(TakesSlowPath, true);
}
default:
return GetByIdStatus(TakesSlowPath, true);
}
RELEASE_ASSERT_NOT_REACHED();
return GetByIdStatus();
}
