blob: 8609955e77c05ec3b09a9bce0cf0ea50d5d18097 [file] [log] [blame]
// Copyright 2015 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/compiler/js-native-context-specialization.h"
#include "src/accessors.h"
#include "src/api-inl.h"
#include "src/code-factory.h"
#include "src/compiler/access-builder.h"
#include "src/compiler/access-info.h"
#include "src/compiler/allocation-builder.h"
#include "src/compiler/compilation-dependencies.h"
#include "src/compiler/js-graph.h"
#include "src/compiler/js-operator.h"
#include "src/compiler/linkage.h"
#include "src/compiler/node-matchers.h"
#include "src/compiler/property-access-builder.h"
#include "src/compiler/type-cache.h"
#include "src/feedback-vector.h"
#include "src/field-index-inl.h"
#include "src/isolate-inl.h"
#include "src/objects/js-array-inl.h"
#include "src/objects/templates.h"
#include "src/vector-slot-pair.h"
namespace v8 {
namespace internal {
namespace compiler {
// This is needed for gc_mole which will compile this file without the full set
// of GN defined macros.
#ifndef V8_TYPED_ARRAY_MAX_SIZE_IN_HEAP
#define V8_TYPED_ARRAY_MAX_SIZE_IN_HEAP 64
#endif
namespace {
bool HasNumberMaps(MapHandles const& maps) {
for (auto map : maps) {
if (map->instance_type() == HEAP_NUMBER_TYPE) return true;
}
return false;
}
bool HasOnlyJSArrayMaps(MapHandles const& maps) {
for (auto map : maps) {
if (!map->IsJSArrayMap()) return false;
}
return true;
}
} // namespace
struct JSNativeContextSpecialization::ScriptContextTableLookupResult {
Handle<Context> context;
bool immutable;
int index;
};
JSNativeContextSpecialization::JSNativeContextSpecialization(
Editor* editor, JSGraph* jsgraph, JSHeapBroker* js_heap_broker, Flags flags,
Handle<Context> native_context, CompilationDependencies* dependencies,
Zone* zone)
: AdvancedReducer(editor),
jsgraph_(jsgraph),
js_heap_broker_(js_heap_broker),
flags_(flags),
global_object_(native_context->global_object(), jsgraph->isolate()),
global_proxy_(JSGlobalProxy::cast(native_context->global_proxy()),
jsgraph->isolate()),
native_context_(js_heap_broker, native_context),
dependencies_(dependencies),
zone_(zone),
type_cache_(TypeCache::Get()) {}
Reduction JSNativeContextSpecialization::Reduce(Node* node) {
switch (node->opcode()) {
case IrOpcode::kJSAdd:
return ReduceJSAdd(node);
case IrOpcode::kJSGetSuperConstructor:
return ReduceJSGetSuperConstructor(node);
case IrOpcode::kJSInstanceOf:
return ReduceJSInstanceOf(node);
case IrOpcode::kJSHasInPrototypeChain:
return ReduceJSHasInPrototypeChain(node);
case IrOpcode::kJSOrdinaryHasInstance:
return ReduceJSOrdinaryHasInstance(node);
case IrOpcode::kJSPromiseResolve:
return ReduceJSPromiseResolve(node);
case IrOpcode::kJSResolvePromise:
return ReduceJSResolvePromise(node);
case IrOpcode::kJSLoadContext:
return ReduceJSLoadContext(node);
case IrOpcode::kJSLoadGlobal:
return ReduceJSLoadGlobal(node);
case IrOpcode::kJSStoreGlobal:
return ReduceJSStoreGlobal(node);
case IrOpcode::kJSLoadNamed:
return ReduceJSLoadNamed(node);
case IrOpcode::kJSStoreNamed:
return ReduceJSStoreNamed(node);
case IrOpcode::kJSLoadProperty:
return ReduceJSLoadProperty(node);
case IrOpcode::kJSStoreProperty:
return ReduceJSStoreProperty(node);
case IrOpcode::kJSStoreNamedOwn:
return ReduceJSStoreNamedOwn(node);
case IrOpcode::kJSStoreDataPropertyInLiteral:
return ReduceJSStoreDataPropertyInLiteral(node);
case IrOpcode::kJSStoreInArrayLiteral:
return ReduceJSStoreInArrayLiteral(node);
default:
break;
}
return NoChange();
}
Reduction JSNativeContextSpecialization::ReduceJSAdd(Node* node) {
// TODO(turbofan): This has to run together with the inlining and
// native context specialization to be able to leverage the string
// constant-folding for optimizing property access, but we should
// nevertheless find a better home for this at some point.
DCHECK_EQ(IrOpcode::kJSAdd, node->opcode());
// Constant-fold string concatenation.
HeapObjectBinopMatcher m(node);
if (m.left().HasValue() && m.left().Value()->IsString() &&
m.right().HasValue() && m.right().Value()->IsString()) {
Handle<String> left = Handle<String>::cast(m.left().Value());
Handle<String> right = Handle<String>::cast(m.right().Value());
if (left->length() + right->length() <= String::kMaxLength) {
Handle<String> result =
factory()->NewConsString(left, right).ToHandleChecked();
Node* value = jsgraph()->HeapConstant(result);
ReplaceWithValue(node, value);
return Replace(value);
}
}
return NoChange();
}
Reduction JSNativeContextSpecialization::ReduceJSGetSuperConstructor(
Node* node) {
DCHECK_EQ(IrOpcode::kJSGetSuperConstructor, node->opcode());
Node* constructor = NodeProperties::GetValueInput(node, 0);
// Check if the input is a known JSFunction.
HeapObjectMatcher m(constructor);
if (!m.HasValue()) return NoChange();
Handle<JSFunction> function = Handle<JSFunction>::cast(m.Value());
Handle<Map> function_map(function->map(), isolate());
Handle<Object> function_prototype(function_map->prototype(), isolate());
// We can constant-fold the super constructor access if the
// {function}s map is stable, i.e. we can use a code dependency
// to guard against [[Prototype]] changes of {function}.
if (function_map->is_stable() && function_prototype->IsConstructor()) {
dependencies()->DependOnStableMap(MapRef(js_heap_broker(), function_map));
Node* value = jsgraph()->Constant(function_prototype);
ReplaceWithValue(node, value);
return Replace(value);
}
return NoChange();
}
Reduction JSNativeContextSpecialization::ReduceJSInstanceOf(Node* node) {
DCHECK_EQ(IrOpcode::kJSInstanceOf, node->opcode());
FeedbackParameter const& p = FeedbackParameterOf(node->op());
Node* object = NodeProperties::GetValueInput(node, 0);
Node* constructor = NodeProperties::GetValueInput(node, 1);
Node* context = NodeProperties::GetContextInput(node);
Node* effect = NodeProperties::GetEffectInput(node);
Node* frame_state = NodeProperties::GetFrameStateInput(node);
Node* control = NodeProperties::GetControlInput(node);
// Check if the right hand side is a known {receiver}, or
// we have feedback from the InstanceOfIC.
Handle<JSObject> receiver;
HeapObjectMatcher m(constructor);
if (m.HasValue() && m.Value()->IsJSObject()) {
receiver = Handle<JSObject>::cast(m.Value());
} else if (p.feedback().IsValid()) {
FeedbackNexus nexus(p.feedback().vector(), p.feedback().slot());
if (!nexus.GetConstructorFeedback().ToHandle(&receiver)) return NoChange();
} else {
return NoChange();
}
Handle<Map> receiver_map(receiver->map(), isolate());
// Compute property access info for @@hasInstance on {receiver}.
PropertyAccessInfo access_info;
AccessInfoFactory access_info_factory(js_heap_broker(), dependencies(),
native_context().object<Context>(),
graph()->zone());
if (!access_info_factory.ComputePropertyAccessInfo(
receiver_map, factory()->has_instance_symbol(), AccessMode::kLoad,
&access_info)) {
return NoChange();
}
PropertyAccessBuilder access_builder(jsgraph(), js_heap_broker(),
dependencies());
if (access_info.IsNotFound()) {
// If there's no @@hasInstance handler, the OrdinaryHasInstance operation
// takes over, but that requires the {receiver} to be callable.
if (receiver->IsCallable()) {
// Determine actual holder and perform prototype chain checks.
Handle<JSObject> holder;
if (access_info.holder().ToHandle(&holder)) {
dependencies()->DependOnStablePrototypeChains(
js_heap_broker(), native_context().object<Context>(),
access_info.receiver_maps(), holder);
}
// Check that {constructor} is actually {receiver}.
constructor = access_builder.BuildCheckValue(constructor, &effect,
control, receiver);
// Monomorphic property access.
access_builder.BuildCheckMaps(constructor, &effect, control,
access_info.receiver_maps());
// Lower to OrdinaryHasInstance(C, O).
NodeProperties::ReplaceValueInput(node, constructor, 0);
NodeProperties::ReplaceValueInput(node, object, 1);
NodeProperties::ReplaceEffectInput(node, effect);
NodeProperties::ChangeOp(node, javascript()->OrdinaryHasInstance());
Reduction const reduction = ReduceJSOrdinaryHasInstance(node);
return reduction.Changed() ? reduction : Changed(node);
}
} else if (access_info.IsDataConstant() ||
access_info.IsDataConstantField()) {
// Determine actual holder and perform prototype chain checks.
Handle<JSObject> holder;
if (access_info.holder().ToHandle(&holder)) {
dependencies()->DependOnStablePrototypeChains(
js_heap_broker(), native_context().object<Context>(),
access_info.receiver_maps(), holder);
} else {
holder = receiver;
}
Handle<Object> constant;
if (access_info.IsDataConstant()) {
DCHECK(!FLAG_track_constant_fields);
constant = access_info.constant();
} else {
DCHECK(FLAG_track_constant_fields);
DCHECK(access_info.IsDataConstantField());
// The value must be callable therefore tagged.
DCHECK(CanBeTaggedPointer(access_info.field_representation()));
FieldIndex field_index = access_info.field_index();
constant = JSObject::FastPropertyAt(holder, Representation::Tagged(),
field_index);
}
DCHECK(constant->IsCallable());
// Check that {constructor} is actually {receiver}.
constructor =
access_builder.BuildCheckValue(constructor, &effect, control, receiver);
// Monomorphic property access.
access_builder.BuildCheckMaps(constructor, &effect, control,
access_info.receiver_maps());
// Create a nested frame state inside the current method's most-recent frame
// state that will ensure that deopts that happen after this point will not
// fallback to the last Checkpoint--which would completely re-execute the
// instanceof logic--but rather create an activation of a version of the
// ToBoolean stub that finishes the remaining work of instanceof and returns
// to the caller without duplicating side-effects upon a lazy deopt.
Node* continuation_frame_state = CreateStubBuiltinContinuationFrameState(
jsgraph(), Builtins::kToBooleanLazyDeoptContinuation, context, nullptr,
0, frame_state, ContinuationFrameStateMode::LAZY);
// Call the @@hasInstance handler.
Node* target = jsgraph()->Constant(constant);
node->InsertInput(graph()->zone(), 0, target);
node->ReplaceInput(1, constructor);
node->ReplaceInput(2, object);
node->ReplaceInput(4, continuation_frame_state);
node->ReplaceInput(5, effect);
NodeProperties::ChangeOp(
node, javascript()->Call(3, CallFrequency(), VectorSlotPair(),
ConvertReceiverMode::kNotNullOrUndefined));
// Rewire the value uses of {node} to ToBoolean conversion of the result.
Node* value = graph()->NewNode(simplified()->ToBoolean(), node);
for (Edge edge : node->use_edges()) {
if (NodeProperties::IsValueEdge(edge) && edge.from() != value) {
edge.UpdateTo(value);
Revisit(edge.from());
}
}
return Changed(node);
}
return NoChange();
}
JSNativeContextSpecialization::InferHasInPrototypeChainResult
JSNativeContextSpecialization::InferHasInPrototypeChain(
Node* receiver, Node* effect, Handle<HeapObject> prototype) {
ZoneHandleSet<Map> receiver_maps;
NodeProperties::InferReceiverMapsResult result =
NodeProperties::InferReceiverMaps(isolate(), receiver, effect,
&receiver_maps);
if (result == NodeProperties::kNoReceiverMaps) return kMayBeInPrototypeChain;
// Check if either all or none of the {receiver_maps} have the given
// {prototype} in their prototype chain.
bool all = true;
bool none = true;
for (size_t i = 0; i < receiver_maps.size(); ++i) {
Handle<Map> receiver_map = receiver_maps[i];
if (receiver_map->instance_type() <= LAST_SPECIAL_RECEIVER_TYPE) {
return kMayBeInPrototypeChain;
}
if (result == NodeProperties::kUnreliableReceiverMaps) {
// In case of an unreliable {result} we need to ensure that all
// {receiver_maps} are stable, because otherwise we cannot trust
// the {receiver_maps} information, since arbitrary side-effects
// may have happened.
if (!receiver_map->is_stable()) {
return kMayBeInPrototypeChain;
}
}
for (PrototypeIterator j(isolate(), receiver_map);; j.Advance()) {
if (j.IsAtEnd()) {
all = false;
break;
}
Handle<HeapObject> const current =
PrototypeIterator::GetCurrent<HeapObject>(j);
if (current.is_identical_to(prototype)) {
none = false;
break;
}
if (!current->map()->is_stable() ||
current->map()->instance_type() <= LAST_SPECIAL_RECEIVER_TYPE) {
return kMayBeInPrototypeChain;
}
}
}
DCHECK_IMPLIES(all, !none);
DCHECK_IMPLIES(none, !all);
if (all) return kIsInPrototypeChain;
if (none) return kIsNotInPrototypeChain;
return kMayBeInPrototypeChain;
}
Reduction JSNativeContextSpecialization::ReduceJSHasInPrototypeChain(
Node* node) {
DCHECK_EQ(IrOpcode::kJSHasInPrototypeChain, node->opcode());
Node* value = NodeProperties::GetValueInput(node, 0);
Node* prototype = NodeProperties::GetValueInput(node, 1);
Node* effect = NodeProperties::GetEffectInput(node);
// Check if we can constant-fold the prototype chain walk
// for the given {value} and the {prototype}.
HeapObjectMatcher m(prototype);
if (m.HasValue()) {
InferHasInPrototypeChainResult result =
InferHasInPrototypeChain(value, effect, m.Value());
if (result != kMayBeInPrototypeChain) {
Node* value = jsgraph()->BooleanConstant(result == kIsInPrototypeChain);
ReplaceWithValue(node, value);
return Replace(value);
}
}
return NoChange();
}
Reduction JSNativeContextSpecialization::ReduceJSOrdinaryHasInstance(
Node* node) {
DCHECK_EQ(IrOpcode::kJSOrdinaryHasInstance, node->opcode());
Node* constructor = NodeProperties::GetValueInput(node, 0);
Node* object = NodeProperties::GetValueInput(node, 1);
// Check if the {constructor} is known at compile time.
HeapObjectMatcher m(constructor);
if (!m.HasValue()) return NoChange();
// Check if the {constructor} is a JSBoundFunction.
if (m.Value()->IsJSBoundFunction()) {
// OrdinaryHasInstance on bound functions turns into a recursive
// invocation of the instanceof operator again.
// ES6 section 7.3.19 OrdinaryHasInstance (C, O) step 2.
Handle<JSBoundFunction> function = Handle<JSBoundFunction>::cast(m.Value());
Handle<JSReceiver> bound_target_function(function->bound_target_function(),
isolate());
NodeProperties::ReplaceValueInput(node, object, 0);
NodeProperties::ReplaceValueInput(
node, jsgraph()->HeapConstant(bound_target_function), 1);
NodeProperties::ChangeOp(node, javascript()->InstanceOf(VectorSlotPair()));
Reduction const reduction = ReduceJSInstanceOf(node);
return reduction.Changed() ? reduction : Changed(node);
}
// Check if the {constructor} is a JSFunction.
if (m.Value()->IsJSFunction()) {
// Check if the {function} is a constructor and has an instance "prototype".
Handle<JSFunction> function = Handle<JSFunction>::cast(m.Value());
if (function->IsConstructor() && function->has_prototype_slot() &&
function->has_instance_prototype() &&
function->prototype()->IsJSReceiver()) {
// Ensure that the {function} has a valid initial map, so we can
// depend on that for the prototype constant-folding below.
JSFunction::EnsureHasInitialMap(function);
MapRef initial_map = dependencies()->DependOnInitialMap(
JSFunctionRef(js_heap_broker(), function));
Node* prototype = jsgraph()->Constant(
handle(initial_map.object<Map>()->prototype(), isolate()));
// Lower the {node} to JSHasInPrototypeChain.
NodeProperties::ReplaceValueInput(node, object, 0);
NodeProperties::ReplaceValueInput(node, prototype, 1);
NodeProperties::ChangeOp(node, javascript()->HasInPrototypeChain());
Reduction const reduction = ReduceJSHasInPrototypeChain(node);
return reduction.Changed() ? reduction : Changed(node);
}
}
return NoChange();
}
// ES section #sec-promise-resolve
Reduction JSNativeContextSpecialization::ReduceJSPromiseResolve(Node* node) {
DCHECK_EQ(IrOpcode::kJSPromiseResolve, node->opcode());
Node* constructor = NodeProperties::GetValueInput(node, 0);
Node* value = NodeProperties::GetValueInput(node, 1);
Node* context = NodeProperties::GetContextInput(node);
Node* frame_state = NodeProperties::GetFrameStateInput(node);
Node* effect = NodeProperties::GetEffectInput(node);
Node* control = NodeProperties::GetControlInput(node);
// Check if the {constructor} is the %Promise% function.
HeapObjectMatcher m(constructor);
if (!m.Is(handle(native_context().object<Context>()->promise_function(),
isolate())))
return NoChange();
// Check if we know something about the {value}.
ZoneHandleSet<Map> value_maps;
NodeProperties::InferReceiverMapsResult result =
NodeProperties::InferReceiverMaps(isolate(), value, effect, &value_maps);
if (result == NodeProperties::kNoReceiverMaps) return NoChange();
DCHECK_NE(0, value_maps.size());
// Check that the {value} cannot be a JSPromise.
for (Handle<Map> const value_map : value_maps) {
if (value_map->IsJSPromiseMap()) return NoChange();
}
// Create a %Promise% instance and resolve it with {value}.
Node* promise = effect =
graph()->NewNode(javascript()->CreatePromise(), context, effect);
effect = graph()->NewNode(javascript()->ResolvePromise(), promise, value,
context, frame_state, effect, control);
ReplaceWithValue(node, promise, effect, control);
return Replace(promise);
}
// ES section #sec-promise-resolve-functions
Reduction JSNativeContextSpecialization::ReduceJSResolvePromise(Node* node) {
DCHECK_EQ(IrOpcode::kJSResolvePromise, node->opcode());
Node* promise = NodeProperties::GetValueInput(node, 0);
Node* resolution = NodeProperties::GetValueInput(node, 1);
Node* context = NodeProperties::GetContextInput(node);
Node* effect = NodeProperties::GetEffectInput(node);
Node* control = NodeProperties::GetControlInput(node);
// Check if we know something about the {resolution}.
ZoneHandleSet<Map> resolution_maps;
NodeProperties::InferReceiverMapsResult result =
NodeProperties::InferReceiverMaps(isolate(), resolution, effect,
&resolution_maps);
if (result != NodeProperties::kReliableReceiverMaps) return NoChange();
DCHECK_NE(0, resolution_maps.size());
// Compute property access info for "then" on {resolution}.
PropertyAccessInfo access_info;
AccessInfoFactory access_info_factory(js_heap_broker(), dependencies(),
native_context().object<Context>(),
graph()->zone());
if (!access_info_factory.ComputePropertyAccessInfo(
MapHandles(resolution_maps.begin(), resolution_maps.end()),
factory()->then_string(), AccessMode::kLoad, &access_info)) {
return NoChange();
}
// We can further optimize the case where {resolution}
// definitely doesn't have a "then" property.
if (!access_info.IsNotFound()) return NoChange();
PropertyAccessBuilder access_builder(jsgraph(), js_heap_broker(),
dependencies());
// Add proper dependencies on the {resolution}s [[Prototype]]s.
Handle<JSObject> holder;
if (access_info.holder().ToHandle(&holder)) {
dependencies()->DependOnStablePrototypeChains(
js_heap_broker(), native_context().object<Context>(),
access_info.receiver_maps(), holder);
}
// Simply fulfill the {promise} with the {resolution}.
Node* value = effect =
graph()->NewNode(javascript()->FulfillPromise(), promise, resolution,
context, effect, control);
ReplaceWithValue(node, value, effect, control);
return Replace(value);
}
Reduction JSNativeContextSpecialization::ReduceJSLoadContext(Node* node) {
DCHECK_EQ(IrOpcode::kJSLoadContext, node->opcode());
ContextAccess const& access = ContextAccessOf(node->op());
// Specialize JSLoadContext(NATIVE_CONTEXT_INDEX) to the known native
// context (if any), so we can constant-fold those fields, which is
// safe, since the NATIVE_CONTEXT_INDEX slot is always immutable.
if (access.index() == Context::NATIVE_CONTEXT_INDEX) {
Node* value = jsgraph()->Constant(native_context());
ReplaceWithValue(node, value);
return Replace(value);
}
return NoChange();
}
namespace {
FieldAccess ForPropertyCellValue(MachineRepresentation representation,
Type type, MaybeHandle<Map> map,
Handle<Name> name) {
WriteBarrierKind kind = kFullWriteBarrier;
if (representation == MachineRepresentation::kTaggedSigned) {
kind = kNoWriteBarrier;
} else if (representation == MachineRepresentation::kTaggedPointer) {
kind = kPointerWriteBarrier;
}
MachineType r = MachineType::TypeForRepresentation(representation);
FieldAccess access = {
kTaggedBase, PropertyCell::kValueOffset, name, map, type, r, kind};
return access;
}
} // namespace
Reduction JSNativeContextSpecialization::ReduceGlobalAccess(
Node* node, Node* receiver, Node* value, Handle<Name> name,
AccessMode access_mode, Node* index) {
Node* effect = NodeProperties::GetEffectInput(node);
Node* control = NodeProperties::GetControlInput(node);
// Lookup on the global object. We only deal with own data properties
// of the global object here (represented as PropertyCell).
LookupIterator it(isolate(), global_object(), name, LookupIterator::OWN);
it.TryLookupCachedProperty();
if (it.state() != LookupIterator::DATA) return NoChange();
if (!it.GetHolder<JSObject>()->IsJSGlobalObject()) return NoChange();
Handle<PropertyCell> property_cell = it.GetPropertyCell();
PropertyDetails property_details = property_cell->property_details();
Handle<Object> property_cell_value(property_cell->value(), isolate());
PropertyCellType property_cell_type = property_details.cell_type();
// We have additional constraints for stores.
if (access_mode == AccessMode::kStore) {
if (property_details.IsReadOnly()) {
// Don't even bother trying to lower stores to read-only data properties.
return NoChange();
} else if (property_cell_type == PropertyCellType::kUndefined) {
// There's no fast-path for dealing with undefined property cells.
return NoChange();
} else if (property_cell_type == PropertyCellType::kConstantType) {
// There's also no fast-path to store to a global cell which pretended
// to be stable, but is no longer stable now.
if (property_cell_value->IsHeapObject() &&
!Handle<HeapObject>::cast(property_cell_value)->map()->is_stable()) {
return NoChange();
}
}
}
// Ensure that {index} matches the specified {name} (if {index} is given).
if (index != nullptr) {
effect = BuildCheckEqualsName(name, index, effect, control);
}
// Check if we have a {receiver} to validate. If so, we need to check that
// the {receiver} is actually the JSGlobalProxy for the native context that
// we are specializing to.
if (receiver != nullptr) {
Node* check = graph()->NewNode(simplified()->ReferenceEqual(), receiver,
jsgraph()->HeapConstant(global_proxy()));
effect = graph()->NewNode(
simplified()->CheckIf(DeoptimizeReason::kReceiverNotAGlobalProxy),
check, effect, control);
}
if (access_mode == AccessMode::kLoad) {
// Load from non-configurable, read-only data property on the global
// object can be constant-folded, even without deoptimization support.
if (!property_details.IsConfigurable() && property_details.IsReadOnly()) {
value = jsgraph()->Constant(property_cell_value);
} else {
// Record a code dependency on the cell if we can benefit from the
// additional feedback, or the global property is configurable (i.e.
// can be deleted or reconfigured to an accessor property).
if (property_details.cell_type() != PropertyCellType::kMutable ||
property_details.IsConfigurable()) {
dependencies()->DependOnGlobalProperty(
PropertyCellRef(js_heap_broker(), property_cell));
}
// Load from constant/undefined global property can be constant-folded.
if (property_details.cell_type() == PropertyCellType::kConstant ||
property_details.cell_type() == PropertyCellType::kUndefined) {
value = jsgraph()->Constant(property_cell_value);
} else {
// Load from constant type cell can benefit from type feedback.
MaybeHandle<Map> map;
Type property_cell_value_type = Type::NonInternal();
MachineRepresentation representation = MachineRepresentation::kTagged;
if (property_details.cell_type() == PropertyCellType::kConstantType) {
// Compute proper type based on the current value in the cell.
if (property_cell_value->IsSmi()) {
property_cell_value_type = Type::SignedSmall();
representation = MachineRepresentation::kTaggedSigned;
} else if (property_cell_value->IsNumber()) {
property_cell_value_type = Type::Number();
representation = MachineRepresentation::kTaggedPointer;
} else {
Handle<Map> property_cell_value_map(
Handle<HeapObject>::cast(property_cell_value)->map(),
isolate());
property_cell_value_type =
Type::For(js_heap_broker(), property_cell_value_map);
representation = MachineRepresentation::kTaggedPointer;
// We can only use the property cell value map for map check
// elimination if it's stable, i.e. the HeapObject wasn't
// mutated without the cell state being updated.
if (property_cell_value_map->is_stable()) {
dependencies()->DependOnStableMap(
MapRef(js_heap_broker(), property_cell_value_map));
map = property_cell_value_map;
}
}
}
value = effect = graph()->NewNode(
simplified()->LoadField(ForPropertyCellValue(
representation, property_cell_value_type, map, name)),
jsgraph()->HeapConstant(property_cell), effect, control);
}
}
} else {
DCHECK_EQ(AccessMode::kStore, access_mode);
DCHECK(!property_details.IsReadOnly());
switch (property_details.cell_type()) {
case PropertyCellType::kUndefined: {
UNREACHABLE();
break;
}
case PropertyCellType::kConstant: {
// Record a code dependency on the cell, and just deoptimize if the new
// value doesn't match the previous value stored inside the cell.
dependencies()->DependOnGlobalProperty(
PropertyCellRef(js_heap_broker(), property_cell));
Node* check =
graph()->NewNode(simplified()->ReferenceEqual(), value,
jsgraph()->Constant(property_cell_value));
effect = graph()->NewNode(
simplified()->CheckIf(DeoptimizeReason::kValueMismatch), check,
effect, control);
break;
}
case PropertyCellType::kConstantType: {
// Record a code dependency on the cell, and just deoptimize if the new
// values' type doesn't match the type of the previous value in the
// cell.
dependencies()->DependOnGlobalProperty(
PropertyCellRef(js_heap_broker(), property_cell));
Type property_cell_value_type;
MachineRepresentation representation = MachineRepresentation::kTagged;
if (property_cell_value->IsHeapObject()) {
// We cannot do anything if the {property_cell_value}s map is no
// longer stable.
Handle<Map> property_cell_value_map(
Handle<HeapObject>::cast(property_cell_value)->map(), isolate());
DCHECK(property_cell_value_map->is_stable());
dependencies()->DependOnStableMap(
MapRef(js_heap_broker(), property_cell_value_map));
// Check that the {value} is a HeapObject.
value = effect = graph()->NewNode(simplified()->CheckHeapObject(),
value, effect, control);
// Check {value} map against the {property_cell} map.
effect =
graph()->NewNode(simplified()->CheckMaps(
CheckMapsFlag::kNone,
ZoneHandleSet<Map>(property_cell_value_map)),
value, effect, control);
property_cell_value_type = Type::OtherInternal();
representation = MachineRepresentation::kTaggedPointer;
} else {
// Check that the {value} is a Smi.
value = effect = graph()->NewNode(
simplified()->CheckSmi(VectorSlotPair()), value, effect, control);
property_cell_value_type = Type::SignedSmall();
representation = MachineRepresentation::kTaggedSigned;
}
effect = graph()->NewNode(simplified()->StoreField(ForPropertyCellValue(
representation, property_cell_value_type,
MaybeHandle<Map>(), name)),
jsgraph()->HeapConstant(property_cell), value,
effect, control);
break;
}
case PropertyCellType::kMutable: {
// Record a code dependency on the cell, and just deoptimize if the
// property ever becomes read-only.
dependencies()->DependOnGlobalProperty(
PropertyCellRef(js_heap_broker(), property_cell));
effect = graph()->NewNode(
simplified()->StoreField(ForPropertyCellValue(
MachineRepresentation::kTagged, Type::NonInternal(),
MaybeHandle<Map>(), name)),
jsgraph()->HeapConstant(property_cell), value, effect, control);
break;
}
}
}
ReplaceWithValue(node, value, effect, control);
return Replace(value);
}
Reduction JSNativeContextSpecialization::ReduceJSLoadGlobal(Node* node) {
DCHECK_EQ(IrOpcode::kJSLoadGlobal, node->opcode());
NameRef name(js_heap_broker(), LoadGlobalParametersOf(node->op()).name());
Node* effect = NodeProperties::GetEffectInput(node);
// Try to lookup the name on the script context table first (lexical scoping).
base::Optional<ScriptContextTableRef::LookupResult> result =
native_context().script_context_table().lookup(name);
if (result) {
ObjectRef contents = result->context.get(result->index);
OddballType oddball_type = contents.oddball_type();
if (oddball_type == OddballType::kHole) {
return NoChange();
}
Node* context = jsgraph()->Constant(result->context);
Node* value = effect = graph()->NewNode(
javascript()->LoadContext(0, result->index, result->immutable), context,
effect);
ReplaceWithValue(node, value, effect);
return Replace(value);
}
// Lookup the {name} on the global object instead.
return ReduceGlobalAccess(node, nullptr, nullptr, name.object<Name>(),
AccessMode::kLoad);
}
Reduction JSNativeContextSpecialization::ReduceJSStoreGlobal(Node* node) {
DCHECK_EQ(IrOpcode::kJSStoreGlobal, node->opcode());
NameRef name(js_heap_broker(), StoreGlobalParametersOf(node->op()).name());
Node* value = NodeProperties::GetValueInput(node, 0);
Node* effect = NodeProperties::GetEffectInput(node);
Node* control = NodeProperties::GetControlInput(node);
// Try to lookup the name on the script context table first (lexical scoping).
base::Optional<ScriptContextTableRef::LookupResult> result =
native_context().script_context_table().lookup(name);
if (result) {
ObjectRef contents = result->context.get(result->index);
OddballType oddball_type = contents.oddball_type();
if (oddball_type == OddballType::kHole || result->immutable) {
return NoChange();
}
Node* context = jsgraph()->Constant(result->context);
effect = graph()->NewNode(javascript()->StoreContext(0, result->index),
value, context, effect, control);
ReplaceWithValue(node, value, effect, control);
return Replace(value);
}
// Lookup the {name} on the global object instead.
return ReduceGlobalAccess(node, nullptr, value, name.object<Name>(),
AccessMode::kStore);
}
Reduction JSNativeContextSpecialization::ReduceNamedAccess(
Node* node, Node* value, MapHandles const& receiver_maps, Handle<Name> name,
AccessMode access_mode, Node* index) {
DCHECK(node->opcode() == IrOpcode::kJSLoadNamed ||
node->opcode() == IrOpcode::kJSStoreNamed ||
node->opcode() == IrOpcode::kJSLoadProperty ||
node->opcode() == IrOpcode::kJSStoreProperty ||
node->opcode() == IrOpcode::kJSStoreNamedOwn);
Node* receiver = NodeProperties::GetValueInput(node, 0);
Node* context = NodeProperties::GetContextInput(node);
Node* frame_state = NodeProperties::GetFrameStateInput(node);
Node* effect = NodeProperties::GetEffectInput(node);
Node* control = NodeProperties::GetControlInput(node);
// Check if we have an access o.x or o.x=v where o is the current
// native contexts' global proxy, and turn that into a direct access
// to the current native contexts' global object instead.
if (receiver_maps.size() == 1) {
Handle<Map> receiver_map = receiver_maps.front();
if (receiver_map->IsJSGlobalProxyMap()) {
Object* maybe_constructor = receiver_map->GetConstructor();
// Detached global proxies have |null| as their constructor.
if (maybe_constructor->IsJSFunction() &&
JSFunction::cast(maybe_constructor)->native_context() ==
*native_context().object<Context>()) {
return ReduceGlobalAccess(node, receiver, value, name, access_mode,
index);
}
}
}
// Compute property access infos for the receiver maps.
AccessInfoFactory access_info_factory(js_heap_broker(), dependencies(),
native_context().object<Context>(),
graph()->zone());
ZoneVector<PropertyAccessInfo> access_infos(zone());
if (!access_info_factory.ComputePropertyAccessInfos(
receiver_maps, name, access_mode, &access_infos)) {
return NoChange();
}
// Nothing to do if we have no non-deprecated maps.
if (access_infos.empty()) {
return ReduceSoftDeoptimize(
node, DeoptimizeReason::kInsufficientTypeFeedbackForGenericNamedAccess);
}
// Ensure that {index} matches the specified {name} (if {index} is given).
if (index != nullptr) {
effect = BuildCheckEqualsName(name, index, effect, control);
}
// Collect call nodes to rewire exception edges.
ZoneVector<Node*> if_exception_nodes(zone());
ZoneVector<Node*>* if_exceptions = nullptr;
Node* if_exception = nullptr;
if (NodeProperties::IsExceptionalCall(node, &if_exception)) {
if_exceptions = &if_exception_nodes;
}
PropertyAccessBuilder access_builder(jsgraph(), js_heap_broker(),
dependencies());
// Check for the monomorphic cases.
if (access_infos.size() == 1) {
PropertyAccessInfo access_info = access_infos.front();
// Try to build string check or number check if possible.
// Otherwise build a map check.
if (!access_builder.TryBuildStringCheck(access_info.receiver_maps(),
&receiver, &effect, control) &&
!access_builder.TryBuildNumberCheck(access_info.receiver_maps(),
&receiver, &effect, control)) {
if (HasNumberMaps(access_info.receiver_maps())) {
// We need to also let Smi {receiver}s through in this case, so
// we construct a diamond, guarded by the Sminess of the {receiver}
// and if {receiver} is not a Smi just emit a sequence of map checks.
Node* check = graph()->NewNode(simplified()->ObjectIsSmi(), receiver);
Node* branch = graph()->NewNode(common()->Branch(), check, control);
Node* if_true = graph()->NewNode(common()->IfTrue(), branch);
Node* etrue = effect;
Node* if_false = graph()->NewNode(common()->IfFalse(), branch);
Node* efalse = effect;
{
access_builder.BuildCheckMaps(receiver, &efalse, if_false,
access_info.receiver_maps());
}
control = graph()->NewNode(common()->Merge(2), if_true, if_false);
effect =
graph()->NewNode(common()->EffectPhi(2), etrue, efalse, control);
} else {
receiver =
access_builder.BuildCheckHeapObject(receiver, &effect, control);
access_builder.BuildCheckMaps(receiver, &effect, control,
access_info.receiver_maps());
}
}
// Generate the actual property access.
ValueEffectControl continuation = BuildPropertyAccess(
receiver, value, context, frame_state, effect, control, name,
if_exceptions, access_info, access_mode);
value = continuation.value();
effect = continuation.effect();
control = continuation.control();
} else {
// The final states for every polymorphic branch. We join them with
// Merge+Phi+EffectPhi at the bottom.
ZoneVector<Node*> values(zone());
ZoneVector<Node*> effects(zone());
ZoneVector<Node*> controls(zone());
// Check if {receiver} may be a number.
bool receiverissmi_possible = false;
for (PropertyAccessInfo const& access_info : access_infos) {
if (HasNumberMaps(access_info.receiver_maps())) {
receiverissmi_possible = true;
break;
}
}
// Ensure that {receiver} is a heap object.
Node* receiverissmi_control = nullptr;
Node* receiverissmi_effect = effect;
if (receiverissmi_possible) {
Node* check = graph()->NewNode(simplified()->ObjectIsSmi(), receiver);
Node* branch = graph()->NewNode(common()->Branch(), check, control);
control = graph()->NewNode(common()->IfFalse(), branch);
receiverissmi_control = graph()->NewNode(common()->IfTrue(), branch);
receiverissmi_effect = effect;
} else {
receiver =
access_builder.BuildCheckHeapObject(receiver, &effect, control);
}
// Generate code for the various different property access patterns.
Node* fallthrough_control = control;
for (size_t j = 0; j < access_infos.size(); ++j) {
PropertyAccessInfo const& access_info = access_infos[j];
Node* this_value = value;
Node* this_receiver = receiver;
Node* this_effect = effect;
Node* this_control = fallthrough_control;
// Perform map check on {receiver}.
MapHandles const& receiver_maps = access_info.receiver_maps();
{
// Whether to insert a dedicated MapGuard node into the
// effect to be able to learn from the control flow.
bool insert_map_guard = true;
// Check maps for the {receiver}s.
if (j == access_infos.size() - 1) {
// Last map check on the fallthrough control path, do a
// conditional eager deoptimization exit here.
access_builder.BuildCheckMaps(receiver, &this_effect, this_control,
receiver_maps);
fallthrough_control = nullptr;
// Don't insert a MapGuard in this case, as the CheckMaps
// node already gives you all the information you need
// along the effect chain.
insert_map_guard = false;
} else {
// Explicitly branch on the {receiver_maps}.
ZoneHandleSet<Map> maps;
for (Handle<Map> map : receiver_maps) {
maps.insert(map, graph()->zone());
}
Node* check = this_effect =
graph()->NewNode(simplified()->CompareMaps(maps), receiver,
this_effect, this_control);
Node* branch =
graph()->NewNode(common()->Branch(), check, this_control);
fallthrough_control = graph()->NewNode(common()->IfFalse(), branch);
this_control = graph()->NewNode(common()->IfTrue(), branch);
}
// The Number case requires special treatment to also deal with Smis.
if (HasNumberMaps(receiver_maps)) {
// Join this check with the "receiver is smi" check above.
DCHECK_NOT_NULL(receiverissmi_effect);
DCHECK_NOT_NULL(receiverissmi_control);
this_control = graph()->NewNode(common()->Merge(2), this_control,
receiverissmi_control);
this_effect = graph()->NewNode(common()->EffectPhi(2), this_effect,
receiverissmi_effect, this_control);
receiverissmi_effect = receiverissmi_control = nullptr;
// The {receiver} can also be a Smi in this case, so
// a MapGuard doesn't make sense for this at all.
insert_map_guard = false;
}
// Introduce a MapGuard to learn from this on the effect chain.
if (insert_map_guard) {
ZoneHandleSet<Map> maps;
for (auto receiver_map : receiver_maps) {
maps.insert(receiver_map, graph()->zone());
}
this_effect = graph()->NewNode(simplified()->MapGuard(maps), receiver,
this_effect, this_control);
}
}
// Generate the actual property access.
ValueEffectControl continuation = BuildPropertyAccess(
this_receiver, this_value, context, frame_state, this_effect,
this_control, name, if_exceptions, access_info, access_mode);
values.push_back(continuation.value());
effects.push_back(continuation.effect());
controls.push_back(continuation.control());
}
DCHECK_NULL(fallthrough_control);
// Generate the final merge point for all (polymorphic) branches.
int const control_count = static_cast<int>(controls.size());
if (control_count == 0) {
value = effect = control = jsgraph()->Dead();
} else if (control_count == 1) {
value = values.front();
effect = effects.front();
control = controls.front();
} else {
control = graph()->NewNode(common()->Merge(control_count), control_count,
&controls.front());
values.push_back(control);
value = graph()->NewNode(
common()->Phi(MachineRepresentation::kTagged, control_count),
control_count + 1, &values.front());
effects.push_back(control);
effect = graph()->NewNode(common()->EffectPhi(control_count),
control_count + 1, &effects.front());
}
}
// Properly rewire IfException edges if {node} is inside a try-block.
if (!if_exception_nodes.empty()) {
DCHECK_NOT_NULL(if_exception);
DCHECK_EQ(if_exceptions, &if_exception_nodes);
int const if_exception_count = static_cast<int>(if_exceptions->size());
Node* merge = graph()->NewNode(common()->Merge(if_exception_count),
if_exception_count, &if_exceptions->front());
if_exceptions->push_back(merge);
Node* ephi =
graph()->NewNode(common()->EffectPhi(if_exception_count),
if_exception_count + 1, &if_exceptions->front());
Node* phi = graph()->NewNode(
common()->Phi(MachineRepresentation::kTagged, if_exception_count),
if_exception_count + 1, &if_exceptions->front());
ReplaceWithValue(if_exception, phi, ephi, merge);
}
ReplaceWithValue(node, value, effect, control);
return Replace(value);
}
Reduction JSNativeContextSpecialization::ReduceNamedAccessFromNexus(
Node* node, Node* value, FeedbackNexus const& nexus, Handle<Name> name,
AccessMode access_mode) {
DCHECK(node->opcode() == IrOpcode::kJSLoadNamed ||
node->opcode() == IrOpcode::kJSStoreNamed ||
node->opcode() == IrOpcode::kJSStoreNamedOwn);
Node* const receiver = NodeProperties::GetValueInput(node, 0);
Node* const effect = NodeProperties::GetEffectInput(node);
// Check if we are accessing the current native contexts' global proxy.
HeapObjectMatcher m(receiver);
if (m.HasValue() && m.Value().is_identical_to(global_proxy())) {
// Optimize accesses to the current native contexts' global proxy.
return ReduceGlobalAccess(node, nullptr, value, name, access_mode);
}
// Extract receiver maps from the IC using the {nexus}.
MapHandles receiver_maps;
if (!ExtractReceiverMaps(receiver, effect, nexus, &receiver_maps)) {
return NoChange();
} else if (receiver_maps.empty()) {
if (flags() & kBailoutOnUninitialized) {
return ReduceSoftDeoptimize(
node,
DeoptimizeReason::kInsufficientTypeFeedbackForGenericNamedAccess);
}
return NoChange();
}
DCHECK(!nexus.IsUninitialized());
// Try to lower the named access based on the {receiver_maps}.
return ReduceNamedAccess(node, value, receiver_maps, name, access_mode);
}
Reduction JSNativeContextSpecialization::ReduceJSLoadNamed(Node* node) {
DCHECK_EQ(IrOpcode::kJSLoadNamed, node->opcode());
NamedAccess const& p = NamedAccessOf(node->op());
Node* const receiver = NodeProperties::GetValueInput(node, 0);
Node* const value = jsgraph()->Dead();
// Check if we have a constant receiver.
HeapObjectMatcher m(receiver);
if (m.HasValue()) {
if (m.Value()->IsJSFunction() &&
p.name().is_identical_to(factory()->prototype_string())) {
// Optimize "prototype" property of functions.
Handle<JSFunction> function = Handle<JSFunction>::cast(m.Value());
if (!function->PrototypeRequiresRuntimeLookup()) {
// We need to add a code dependency on the initial map of the
// {function} in order to be notified about changes to the
// "prototype" of {function}.
JSFunction::EnsureHasInitialMap(function);
dependencies()->DependOnInitialMap(
JSFunctionRef(js_heap_broker(), function));
Handle<Object> prototype(function->prototype(), isolate());
Node* value = jsgraph()->Constant(prototype);
ReplaceWithValue(node, value);
return Replace(value);
}
} else if (m.Value()->IsString() &&
p.name().is_identical_to(factory()->length_string())) {
// Constant-fold "length" property on constant strings.
Handle<String> string = Handle<String>::cast(m.Value());
Node* value = jsgraph()->Constant(string->length());
ReplaceWithValue(node, value);
return Replace(value);
}
}
// Extract receiver maps from the load IC using the FeedbackNexus.
if (!p.feedback().IsValid()) return NoChange();
FeedbackNexus nexus(p.feedback().vector(), p.feedback().slot());
// Try to lower the named access based on the {receiver_maps}.
return ReduceNamedAccessFromNexus(node, value, nexus, p.name(),
AccessMode::kLoad);
}
Reduction JSNativeContextSpecialization::ReduceJSStoreNamed(Node* node) {
DCHECK_EQ(IrOpcode::kJSStoreNamed, node->opcode());
NamedAccess const& p = NamedAccessOf(node->op());
Node* const value = NodeProperties::GetValueInput(node, 1);
// Extract receiver maps from the store IC using the FeedbackNexus.
if (!p.feedback().IsValid()) return NoChange();
FeedbackNexus nexus(p.feedback().vector(), p.feedback().slot());
// Try to lower the named access based on the {receiver_maps}.
return ReduceNamedAccessFromNexus(node, value, nexus, p.name(),
AccessMode::kStore);
}
Reduction JSNativeContextSpecialization::ReduceJSStoreNamedOwn(Node* node) {
DCHECK_EQ(IrOpcode::kJSStoreNamedOwn, node->opcode());
StoreNamedOwnParameters const& p = StoreNamedOwnParametersOf(node->op());
Node* const value = NodeProperties::GetValueInput(node, 1);
// Extract receiver maps from the IC using the FeedbackNexus.
if (!p.feedback().IsValid()) return NoChange();
FeedbackNexus nexus(p.feedback().vector(), p.feedback().slot());
// Try to lower the creation of a named property based on the {receiver_maps}.
return ReduceNamedAccessFromNexus(node, value, nexus, p.name(),
AccessMode::kStoreInLiteral);
}
Reduction JSNativeContextSpecialization::ReduceElementAccess(
Node* node, Node* index, Node* value, MapHandles const& receiver_maps,
AccessMode access_mode, KeyedAccessLoadMode load_mode,
KeyedAccessStoreMode store_mode) {
DCHECK(node->opcode() == IrOpcode::kJSLoadProperty ||
node->opcode() == IrOpcode::kJSStoreProperty ||
node->opcode() == IrOpcode::kJSStoreInArrayLiteral);
Node* receiver = NodeProperties::GetValueInput(node, 0);
Node* effect = NodeProperties::GetEffectInput(node);
Node* control = NodeProperties::GetControlInput(node);
Node* frame_state = NodeProperties::FindFrameStateBefore(node);
// Check for keyed access to strings.
if (HasOnlyStringMaps(receiver_maps)) {
// Strings are immutable in JavaScript.
if (access_mode == AccessMode::kStore) return NoChange();
// Ensure that the {receiver} is actually a String.
receiver = effect = graph()->NewNode(
simplified()->CheckString(VectorSlotPair()), receiver, effect, control);
// Determine the {receiver} length.
Node* length = graph()->NewNode(simplified()->StringLength(), receiver);
// Load the single character string from {receiver} or yield undefined
// if the {index} is out of bounds (depending on the {load_mode}).
value = BuildIndexedStringLoad(receiver, index, length, &effect, &control,
load_mode);
} else {
// Retrieve the native context from the given {node}.
// Compute element access infos for the receiver maps.
AccessInfoFactory access_info_factory(js_heap_broker(), dependencies(),
native_context().object<Context>(),
graph()->zone());
ZoneVector<ElementAccessInfo> access_infos(zone());
if (!access_info_factory.ComputeElementAccessInfos(
receiver_maps, access_mode, &access_infos)) {
return NoChange();
}
// Nothing to do if we have no non-deprecated maps.
if (access_infos.empty()) {
return ReduceSoftDeoptimize(
node,
DeoptimizeReason::kInsufficientTypeFeedbackForGenericKeyedAccess);
}
// For holey stores or growing stores, we need to check that the prototype
// chain contains no setters for elements, and we need to guard those checks
// via code dependencies on the relevant prototype maps.
if (access_mode == AccessMode::kStore) {
// TODO(turbofan): We could have a fast path here, that checks for the
// common case of Array or Object prototype only and therefore avoids
// the zone allocation of this vector.
ZoneVector<Handle<Map>> prototype_maps(zone());
for (ElementAccessInfo const& access_info : access_infos) {
for (Handle<Map> receiver_map : access_info.receiver_maps()) {
// If the {receiver_map} has a prototype and it's elements backing
// store is either holey, or we have a potentially growing store,
// then we need to check that all prototypes have stable maps with
// fast elements (and we need to guard against changes to that below).
if (IsHoleyOrDictionaryElementsKind(receiver_map->elements_kind()) ||
IsGrowStoreMode(store_mode)) {
// Make sure all prototypes are stable and have fast elements.
for (Handle<Map> map = receiver_map;;) {
Handle<Object> map_prototype(map->prototype(), isolate());
if (map_prototype->IsNull(isolate())) break;
if (!map_prototype->IsJSObject()) return NoChange();
map = handle(Handle<JSObject>::cast(map_prototype)->map(),
isolate());
if (!map->is_stable()) return NoChange();
if (!IsFastElementsKind(map->elements_kind())) return NoChange();
prototype_maps.push_back(map);
}
}
}
}
// Install dependencies on the relevant prototype maps.
for (Handle<Map> prototype_map : prototype_maps) {
dependencies()->DependOnStableMap(
MapRef(js_heap_broker(), prototype_map));
}
}
// Ensure that {receiver} is a heap object.
PropertyAccessBuilder access_builder(jsgraph(), js_heap_broker(),
dependencies());
receiver = access_builder.BuildCheckHeapObject(receiver, &effect, control);
// Check for the monomorphic case.
if (access_infos.size() == 1) {
ElementAccessInfo access_info = access_infos.front();
// Perform possible elements kind transitions.
for (auto transition : access_info.transitions()) {
Handle<Map> const transition_source = transition.first;
Handle<Map> const transition_target = transition.second;
effect = graph()->NewNode(
simplified()->TransitionElementsKind(ElementsTransition(
IsSimpleMapChangeTransition(transition_source->elements_kind(),
transition_target->elements_kind())
? ElementsTransition::kFastTransition
: ElementsTransition::kSlowTransition,
transition_source, transition_target)),
receiver, effect, control);
}
// TODO(turbofan): The effect/control linearization will not find a
// FrameState after the StoreField or Call that is generated for the
// elements kind transition above. This is because those operators
// don't have the kNoWrite flag on it, even though they are not
// observable by JavaScript.
effect = graph()->NewNode(common()->Checkpoint(), frame_state, effect,
control);
// Perform map check on the {receiver}.
access_builder.BuildCheckMaps(receiver, &effect, control,
access_info.receiver_maps());
// Access the actual element.
ValueEffectControl continuation =
BuildElementAccess(receiver, index, value, effect, control,
access_info, access_mode, load_mode, store_mode);
value = continuation.value();
effect = continuation.effect();
control = continuation.control();
} else {
// The final states for every polymorphic branch. We join them with
// Merge+Phi+EffectPhi at the bottom.
ZoneVector<Node*> values(zone());
ZoneVector<Node*> effects(zone());
ZoneVector<Node*> controls(zone());
// Generate code for the various different element access patterns.
Node* fallthrough_control = control;
for (size_t j = 0; j < access_infos.size(); ++j) {
ElementAccessInfo const& access_info = access_infos[j];
Node* this_receiver = receiver;
Node* this_value = value;
Node* this_index = index;
Node* this_effect = effect;
Node* this_control = fallthrough_control;
// Perform possible elements kind transitions.
for (auto transition : access_info.transitions()) {
Handle<Map> const transition_source = transition.first;
Handle<Map> const transition_target = transition.second;
this_effect = graph()->NewNode(
simplified()->TransitionElementsKind(
ElementsTransition(IsSimpleMapChangeTransition(
transition_source->elements_kind(),
transition_target->elements_kind())
? ElementsTransition::kFastTransition
: ElementsTransition::kSlowTransition,
transition_source, transition_target)),
receiver, this_effect, this_control);
}
// Perform map check(s) on {receiver}.
MapHandles const& receiver_maps = access_info.receiver_maps();
if (j == access_infos.size() - 1) {
// Last map check on the fallthrough control path, do a
// conditional eager deoptimization exit here.
access_builder.BuildCheckMaps(receiver, &this_effect, this_control,
receiver_maps);
fallthrough_control = nullptr;
} else {
// Explicitly branch on the {receiver_maps}.
ZoneHandleSet<Map> maps;
for (Handle<Map> map : receiver_maps) {
maps.insert(map, graph()->zone());
}
Node* check = this_effect =
graph()->NewNode(simplified()->CompareMaps(maps), receiver,
this_effect, fallthrough_control);
Node* branch =
graph()->NewNode(common()->Branch(), check, fallthrough_control);
fallthrough_control = graph()->NewNode(common()->IfFalse(), branch);
this_control = graph()->NewNode(common()->IfTrue(), branch);
// Introduce a MapGuard to learn from this on the effect chain.
this_effect = graph()->NewNode(simplified()->MapGuard(maps), receiver,
this_effect, this_control);
}
// Access the actual element.
ValueEffectControl continuation = BuildElementAccess(
this_receiver, this_index, this_value, this_effect, this_control,
access_info, access_mode, load_mode, store_mode);
values.push_back(continuation.value());
effects.push_back(continuation.effect());
controls.push_back(continuation.control());
}
DCHECK_NULL(fallthrough_control);
// Generate the final merge point for all (polymorphic) branches.
int const control_count = static_cast<int>(controls.size());
if (control_count == 0) {
value = effect = control = jsgraph()->Dead();
} else if (control_count == 1) {
value = values.front();
effect = effects.front();
control = controls.front();
} else {
control = graph()->NewNode(common()->Merge(control_count),
control_count, &controls.front());
values.push_back(control);
value = graph()->NewNode(
common()->Phi(MachineRepresentation::kTagged, control_count),
control_count + 1, &values.front());
effects.push_back(control);
effect = graph()->NewNode(common()->EffectPhi(control_count),
control_count + 1, &effects.front());
}
}
}
ReplaceWithValue(node, value, effect, control);
return Replace(value);
}
Reduction JSNativeContextSpecialization::ReduceKeyedAccess(
Node* node, Node* index, Node* value, FeedbackNexus const& nexus,
AccessMode access_mode, KeyedAccessLoadMode load_mode,
KeyedAccessStoreMode store_mode) {
DCHECK(node->opcode() == IrOpcode::kJSLoadProperty ||
node->opcode() == IrOpcode::kJSStoreProperty);
Node* receiver = NodeProperties::GetValueInput(node, 0);
Node* effect = NodeProperties::GetEffectInput(node);
Node* control = NodeProperties::GetControlInput(node);
// Optimize the case where we load from a constant {receiver}.
if (access_mode == AccessMode::kLoad) {
HeapObjectMatcher mreceiver(receiver);
if (mreceiver.HasValue() && !mreceiver.Value()->IsTheHole(isolate()) &&
!mreceiver.Value()->IsNullOrUndefined(isolate())) {
// Check whether we're accessing a known element on the {receiver}
// that is non-configurable, non-writable (i.e. the {receiver} was
// frozen using Object.freeze).
NumberMatcher mindex(index);
if (mindex.IsInteger() && mindex.IsInRange(0.0, kMaxUInt32 - 1.0)) {
LookupIterator it(isolate(), mreceiver.Value(),
static_cast<uint32_t>(mindex.Value()),
LookupIterator::OWN);
if (it.state() == LookupIterator::DATA) {
if (it.IsReadOnly() && !it.IsConfigurable()) {
// We can safely constant-fold the {index} access to {receiver},
// since the element is non-configurable, non-writable and thus
// cannot change anymore.
value = jsgraph()->Constant(it.GetDataValue());
ReplaceWithValue(node, value, effect, control);
return Replace(value);
}
// Check if the {receiver} is a known constant with a copy-on-write
// backing store, and whether {index} is within the appropriate
// bounds. In that case we can constant-fold the access and only
// check that the {elements} didn't change. This is sufficient as
// the backing store of a copy-on-write JSArray is defensively copied
// whenever the length or the elements (might) change.
//
// What's interesting here is that we don't need to map check the
// {receiver}, since JSArray's will always have their elements in
// the backing store.
if (mreceiver.Value()->IsJSArray()) {
Handle<JSArray> array = Handle<JSArray>::cast(mreceiver.Value());
if (array->elements()->IsCowArray()) {
Node* elements = effect = graph()->NewNode(
simplified()->LoadField(AccessBuilder::ForJSObjectElements()),
receiver, effect, control);
Handle<FixedArray> array_elements(
FixedArray::cast(array->elements()), isolate());
Node* check =
graph()->NewNode(simplified()->ReferenceEqual(), elements,
jsgraph()->HeapConstant(array_elements));
effect = graph()->NewNode(
simplified()->CheckIf(
DeoptimizeReason::kCowArrayElementsChanged),
check, effect, control);
value = jsgraph()->Constant(it.GetDataValue());
ReplaceWithValue(node, value, effect, control);
return Replace(value);
}
}
}
}
// For constant Strings we can eagerly strength-reduce the keyed
// accesses using the known length, which doesn't change.
if (mreceiver.Value()->IsString()) {
Handle<String> string = Handle<String>::cast(mreceiver.Value());
// We can only assume that the {index} is a valid array index if the IC
// is in element access mode and not MEGAMORPHIC, otherwise there's no
// guard for the bounds check below.
if (nexus.ic_state() != MEGAMORPHIC && nexus.GetKeyType() == ELEMENT) {
// Ensure that {index} is less than {receiver} length.
Node* length = jsgraph()->Constant(string->length());
// Load the single character string from {receiver} or yield undefined
// if the {index} is out of bounds (depending on the {load_mode}).
value = BuildIndexedStringLoad(receiver, index, length, &effect,
&control, load_mode);
ReplaceWithValue(node, value, effect, control);
return Replace(value);
}
}
}
}
// Extract receiver maps from the {nexus}.
MapHandles receiver_maps;
if (!ExtractReceiverMaps(receiver, effect, nexus, &receiver_maps)) {
return NoChange();
} else if (receiver_maps.empty()) {
if (flags() & kBailoutOnUninitialized) {
return ReduceSoftDeoptimize(
node,
DeoptimizeReason::kInsufficientTypeFeedbackForGenericKeyedAccess);
}
return NoChange();
}
DCHECK(!nexus.IsUninitialized());
// Optimize access for constant {index}.
HeapObjectMatcher mindex(index);
if (mindex.HasValue() && mindex.Value()->IsPrimitive()) {
// Keyed access requires a ToPropertyKey on the {index} first before
// looking up the property on the object (see ES6 section 12.3.2.1).
// We can only do this for non-observable ToPropertyKey invocations,
// so we limit the constant indices to primitives at this point.
Handle<Name> name;
if (Object::ToName(isolate(), mindex.Value()).ToHandle(&name)) {
uint32_t array_index;
if (name->AsArrayIndex(&array_index)) {
// Use the constant array index.
index = jsgraph()->Constant(static_cast<double>(array_index));
} else {
name = factory()->InternalizeName(name);
return ReduceNamedAccess(node, value, receiver_maps, name, access_mode);
}
}
}
// Check if we have feedback for a named access.
if (Name* name = nexus.FindFirstName()) {
return ReduceNamedAccess(node, value, receiver_maps,
handle(name, isolate()), access_mode, index);
} else if (nexus.GetKeyType() != ELEMENT) {
// The KeyedLoad/StoreIC has seen non-element accesses, so we cannot assume
// that the {index} is a valid array index, thus we just let the IC continue
// to deal with this load/store.
return NoChange();
} else if (nexus.ic_state() == MEGAMORPHIC) {
// The KeyedLoad/StoreIC uses the MEGAMORPHIC state to guard the assumption
// that a numeric {index} is within the valid bounds for {receiver}, i.e.
// it transitions to MEGAMORPHIC once it sees an out-of-bounds access. Thus
// we cannot continue here if the IC state is MEGAMORPHIC.
return NoChange();
}
// Try to lower the element access based on the {receiver_maps}.
return ReduceElementAccess(node, index, value, receiver_maps, access_mode,
load_mode, store_mode);
}
Reduction JSNativeContextSpecialization::ReduceSoftDeoptimize(
Node* node, DeoptimizeReason reason) {
Node* effect = NodeProperties::GetEffectInput(node);
Node* control = NodeProperties::GetControlInput(node);
Node* frame_state = NodeProperties::FindFrameStateBefore(node);
Node* deoptimize = graph()->NewNode(
common()->Deoptimize(DeoptimizeKind::kSoft, reason, VectorSlotPair()),
frame_state, effect, control);
// TODO(bmeurer): This should be on the AdvancedReducer somehow.
NodeProperties::MergeControlToEnd(graph(), common(), deoptimize);
Revisit(graph()->end());
node->TrimInputCount(0);
NodeProperties::ChangeOp(node, common()->Dead());
return Changed(node);
}
Reduction JSNativeContextSpecialization::ReduceJSLoadProperty(Node* node) {
DCHECK_EQ(IrOpcode::kJSLoadProperty, node->opcode());
PropertyAccess const& p = PropertyAccessOf(node->op());
Node* receiver = NodeProperties::GetValueInput(node, 0);
Node* name = NodeProperties::GetValueInput(node, 1);
Node* value = jsgraph()->Dead();
Node* effect = NodeProperties::GetEffectInput(node);
Node* control = NodeProperties::GetControlInput(node);
// We can optimize a property load if it's being used inside a for..in,
// so for code like this:
//
// for (name in receiver) {
// value = receiver[name];
// ...
// }
//
// If the for..in is in fast-mode, we know that the {receiver} has {name}
// as own property, otherwise the enumeration wouldn't include it. The graph
// constructed by the BytecodeGraphBuilder in this case looks like this:
// receiver
// ^ ^
// | |
// | +-+
// | |
// | JSToObject
// | ^
// | |
// | |
// | JSForInNext
// | ^
// | |
// +----+ |
// | |
// | |
// JSLoadProperty
// If the for..in has only seen maps with enum cache consisting of keys
// and indices so far, we can turn the {JSLoadProperty} into a map check
// on the {receiver} and then just load the field value dynamically via
// the {LoadFieldByIndex} operator. The map check is only necessary when
// TurboFan cannot prove that there is no observable side effect between
// the {JSForInNext} and the {JSLoadProperty} node.
//
// Also note that it's safe to look through the {JSToObject}, since the
// [[Get]] operation does an implicit ToObject anyway, and these operations
// are not observable.
if (name->opcode() == IrOpcode::kJSForInNext) {
ForInMode const mode = ForInModeOf(name->op());
if (mode == ForInMode::kUseEnumCacheKeysAndIndices) {
Node* object = NodeProperties::GetValueInput(name, 0);
Node* enumerator = NodeProperties::GetValueInput(name, 2);
Node* index = NodeProperties::GetValueInput(name, 3);
if (object->opcode() == IrOpcode::kJSToObject) {
object = NodeProperties::GetValueInput(object, 0);
}
if (object == receiver) {
// No need to repeat the map check if we can prove that there's no
// observable side effect between {effect} and {name].
if (!NodeProperties::NoObservableSideEffectBetween(effect, name)) {
// Check that the {receiver} map is still valid.
Node* receiver_map = effect =
graph()->NewNode(simplified()->LoadField(AccessBuilder::ForMap()),
receiver, effect, control);
Node* check = graph()->NewNode(simplified()->ReferenceEqual(),
receiver_map, enumerator);
effect = graph()->NewNode(
simplified()->CheckIf(DeoptimizeReason::kWrongMap), check, effect,
control);
}
// Load the enum cache indices from the {cache_type}.
Node* descriptor_array = effect = graph()->NewNode(
simplified()->LoadField(AccessBuilder::ForMapDescriptors()),
enumerator, effect, control);
Node* enum_cache = effect =
graph()->NewNode(simplified()->LoadField(
AccessBuilder::ForDescriptorArrayEnumCache()),
descriptor_array, effect, control);
Node* enum_indices = effect = graph()->NewNode(
simplified()->LoadField(AccessBuilder::ForEnumCacheIndices()),
enum_cache, effect, control);
// Ensure that the {enum_indices} are valid.
Node* check = graph()->NewNode(
simplified()->BooleanNot(),
graph()->NewNode(simplified()->ReferenceEqual(), enum_indices,
jsgraph()->EmptyFixedArrayConstant()));
effect = graph()->NewNode(
simplified()->CheckIf(DeoptimizeReason::kWrongEnumIndices), check,
effect, control);
// Determine the index from the {enum_indices}.
index = effect = graph()->NewNode(
simplified()->LoadElement(
AccessBuilder::ForFixedArrayElement(PACKED_SMI_ELEMENTS)),
enum_indices, index, effect, control);
// Load the actual field value.
Node* value = effect = graph()->NewNode(
simplified()->LoadFieldByIndex(), receiver, index, effect, control);
ReplaceWithValue(node, value, effect, control);
return Replace(value);
}
}
}
// Extract receiver maps from the keyed load IC using the FeedbackNexus.
if (!p.feedback().IsValid()) return NoChange();
FeedbackNexus nexus(p.feedback().vector(), p.feedback().slot());
// Extract the keyed access load mode from the keyed load IC.
KeyedAccessLoadMode load_mode = nexus.GetKeyedAccessLoadMode();
// Try to lower the keyed access based on the {nexus}.
return ReduceKeyedAccess(node, name, value, nexus, AccessMode::kLoad,
load_mode, STANDARD_STORE);
}
Reduction JSNativeContextSpecialization::ReduceJSStoreProperty(Node* node) {
DCHECK_EQ(IrOpcode::kJSStoreProperty, node->opcode());
PropertyAccess const& p = PropertyAccessOf(node->op());
Node* const index = NodeProperties::GetValueInput(node, 1);
Node* const value = NodeProperties::GetValueInput(node, 2);
// Extract receiver maps from the keyed store IC using the FeedbackNexus.
if (!p.feedback().IsValid()) return NoChange();
FeedbackNexus nexus(p.feedback().vector(), p.feedback().slot());
// Extract the keyed access store mode from the keyed store IC.
KeyedAccessStoreMode store_mode = nexus.GetKeyedAccessStoreMode();
// Try to lower the keyed access based on the {nexus}.
return ReduceKeyedAccess(node, index, value, nexus, AccessMode::kStore,
STANDARD_LOAD, store_mode);
}
Node* JSNativeContextSpecialization::InlinePropertyGetterCall(
Node* receiver, Node* context, Node* frame_state, Node** effect,
Node** control, ZoneVector<Node*>* if_exceptions,
PropertyAccessInfo const& access_info) {
Node* target = jsgraph()->Constant(access_info.constant());
FrameStateInfo const& frame_info = FrameStateInfoOf(frame_state->op());
Handle<SharedFunctionInfo> shared_info =
frame_info.shared_info().ToHandleChecked();
// Introduce the call to the getter function.
Node* value;
if (access_info.constant()->IsJSFunction()) {
value = *effect = *control = graph()->NewNode(
jsgraph()->javascript()->Call(2, CallFrequency(), VectorSlotPair(),
ConvertReceiverMode::kNotNullOrUndefined),
target, receiver, context, frame_state, *effect, *control);
} else {
DCHECK(access_info.constant()->IsFunctionTemplateInfo());
Handle<FunctionTemplateInfo> function_template_info(
Handle<FunctionTemplateInfo>::cast(access_info.constant()));
DCHECK(!function_template_info->call_code()->IsUndefined(isolate()));
Node* holder =
access_info.holder().is_null()
? receiver
: jsgraph()->Constant(access_info.holder().ToHandleChecked());
value = InlineApiCall(receiver, holder, frame_state, nullptr, effect,
control, shared_info, function_template_info);
}
// Remember to rewire the IfException edge if this is inside a try-block.
if (if_exceptions != nullptr) {
// Create the appropriate IfException/IfSuccess projections.
Node* const if_exception =
graph()->NewNode(common()->IfException(), *control, *effect);
Node* const if_success = graph()->NewNode(common()->IfSuccess(), *control);
if_exceptions->push_back(if_exception);
*control = if_success;
}
return value;
}
void JSNativeContextSpecialization::InlinePropertySetterCall(
Node* receiver, Node* value, Node* context, Node* frame_state,
Node** effect, Node** control, ZoneVector<Node*>* if_exceptions,
PropertyAccessInfo const& access_info) {
Node* target = jsgraph()->Constant(access_info.constant());
FrameStateInfo const& frame_info = FrameStateInfoOf(frame_state->op());
Handle<SharedFunctionInfo> shared_info =
frame_info.shared_info().ToHandleChecked();
// Introduce the call to the setter function.
if (access_info.constant()->IsJSFunction()) {
*effect = *control = graph()->NewNode(
jsgraph()->javascript()->Call(3, CallFrequency(), VectorSlotPair(),
ConvertReceiverMode::kNotNullOrUndefined),
target, receiver, value, context, frame_state, *effect, *control);
} else {
DCHECK(access_info.constant()->IsFunctionTemplateInfo());
Handle<FunctionTemplateInfo> function_template_info(
Handle<FunctionTemplateInfo>::cast(access_info.constant()));
DCHECK(!function_template_info->call_code()->IsUndefined(isolate()));
Node* holder =
access_info.holder().is_null()
? receiver
: jsgraph()->Constant(access_info.holder().ToHandleChecked());
InlineApiCall(receiver, holder, frame_state, value, effect, control,
shared_info, function_template_info);
}
// Remember to rewire the IfException edge if this is inside a try-block.
if (if_exceptions != nullptr) {
// Create the appropriate IfException/IfSuccess projections.
Node* const if_exception =
graph()->NewNode(common()->IfException(), *control, *effect);
Node* const if_success = graph()->NewNode(common()->IfSuccess(), *control);
if_exceptions->push_back(if_exception);
*control = if_success;
}
}
Node* JSNativeContextSpecialization::InlineApiCall(
Node* receiver, Node* holder, Node* frame_state, Node* value, Node** effect,
Node** control, Handle<SharedFunctionInfo> shared_info,
Handle<FunctionTemplateInfo> function_template_info) {
Handle<CallHandlerInfo> call_handler_info = handle(
CallHandlerInfo::cast(function_template_info->call_code()), isolate());
Handle<Object> call_data_object(call_handler_info->data(), isolate());
// Only setters have a value.
int const argc = value == nullptr ? 0 : 1;
// The stub always expects the receiver as the first param on the stack.
Callable call_api_callback = CodeFactory::CallApiCallback(isolate(), argc);
CallInterfaceDescriptor call_interface_descriptor =
call_api_callback.descriptor();
auto call_descriptor = Linkage::GetStubCallDescriptor(
graph()->zone(), call_interface_descriptor,
call_interface_descriptor.GetStackParameterCount() + argc +
1 /* implicit receiver */,
CallDescriptor::kNeedsFrameState);
Node* data = jsgraph()->Constant(call_data_object);
ApiFunction function(v8::ToCData<Address>(call_handler_info->callback()));
Node* function_reference =
graph()->NewNode(common()->ExternalConstant(ExternalReference::Create(
&function, ExternalReference::DIRECT_API_CALL)));
Node* code = jsgraph()->HeapConstant(call_api_callback.code());
// Add CallApiCallbackStub's register argument as well.
Node* context = jsgraph()->Constant(native_context());
Node* inputs[10] = {code, context, data, holder, function_reference,
receiver};
int index = 6 + argc;
inputs[index++] = frame_state;
inputs[index++] = *effect;
inputs[index++] = *control;
// This needs to stay here because of the edge case described in
// http://crbug.com/675648.
if (value != nullptr) {
inputs[6] = value;
}
return *effect = *control =
graph()->NewNode(common()->Call(call_descriptor), index, inputs);
}
JSNativeContextSpecialization::ValueEffectControl
JSNativeContextSpecialization::BuildPropertyLoad(
Node* receiver, Node* context, Node* frame_state, Node* effect,
Node* control, Handle<Name> name, ZoneVector<Node*>* if_exceptions,
PropertyAccessInfo const& access_info) {
// Determine actual holder and perform prototype chain checks.
Handle<JSObject> holder;
PropertyAccessBuilder access_builder(jsgraph(), js_heap_broker(),
dependencies());
if (access_info.holder().ToHandle(&holder)) {
dependencies()->DependOnStablePrototypeChains(
js_heap_broker(), native_context().object<Context>(),
access_info.receiver_maps(), holder);
}
// Generate the actual property access.
Node* value;
if (access_info.IsNotFound()) {
value = jsgraph()->UndefinedConstant();
} else if (access_info.IsDataConstant()) {
DCHECK(!FLAG_track_constant_fields);
value = jsgraph()->Constant(access_info.constant());
} else if (access_info.IsAccessorConstant()) {
value = InlinePropertyGetterCall(receiver, context, frame_state, &effect,
&control, if_exceptions, access_info);
} else if (access_info.IsModuleExport()) {
Node* cell = jsgraph()->Constant(access_info.export_cell());
value = effect =
graph()->NewNode(simplified()->LoadField(AccessBuilder::ForCellValue()),
cell, effect, control);
} else {
DCHECK(access_info.IsDataField() || access_info.IsDataConstantField());
value = access_builder.BuildLoadDataField(name, access_info, receiver,
&effect, &control);
}
return ValueEffectControl(value, effect, control);
}
JSNativeContextSpecialization::ValueEffectControl
JSNativeContextSpecialization::BuildPropertyAccess(
Node* receiver, Node* value, Node* context, Node* frame_state, Node* effect,
Node* control, Handle<Name> name, ZoneVector<Node*>* if_exceptions,
PropertyAccessInfo const& access_info, AccessMode access_mode) {
switch (access_mode) {
case AccessMode::kLoad:
return BuildPropertyLoad(receiver, context, frame_state, effect, control,
name, if_exceptions, access_info);
case AccessMode::kStore:
case AccessMode::kStoreInLiteral:
return BuildPropertyStore(receiver, value, context, frame_state, effect,
control, name, if_exceptions, access_info,
access_mode);
}
UNREACHABLE();
return ValueEffectControl();
}
JSNativeContextSpecialization::ValueEffectControl
JSNativeContextSpecialization::BuildPropertyStore(
Node* receiver, Node* value, Node* context, Node* frame_state, Node* effect,
Node* control, Handle<Name> name, ZoneVector<Node*>* if_exceptions,
PropertyAccessInfo const& access_info, AccessMode access_mode) {
// Determine actual holder and perform prototype chain checks.
Handle<JSObject> holder;
PropertyAccessBuilder access_builder(jsgraph(), js_heap_broker(),
dependencies());
if (access_info.holder().ToHandle(&holder)) {
DCHECK_NE(AccessMode::kStoreInLiteral, access_mode);
dependencies()->DependOnStablePrototypeChains(
js_heap_broker(), native_context().object<Context>(),
access_info.receiver_maps(), holder);
}
DCHECK(!access_info.IsNotFound());
// Generate the actual property access.
if (access_info.IsDataConstant()) {
DCHECK(!FLAG_track_constant_fields);
Node* constant_value = jsgraph()->Constant(access_info.constant());
Node* check =
graph()->NewNode(simplified()->ReferenceEqual(), value, constant_value);
effect =
graph()->NewNode(simplified()->CheckIf(DeoptimizeReason::kWrongValue),
check, effect, control);
value = constant_value;
} else if (access_info.IsAccessorConstant()) {
InlinePropertySetterCall(receiver, value, context, frame_state, &effect,
&control, if_exceptions, access_info);
} else {
DCHECK(access_info.IsDataField() || access_info.IsDataConstantField());
FieldIndex const field_index = access_info.field_index();
Type const field_type = access_info.field_type();
MachineRepresentation const field_representation =
access_info.field_representation();
Node* storage = receiver;
if (!field_index.is_inobject()) {
storage = effect = graph()->NewNode(
simplified()->LoadField(AccessBuilder::ForJSObjectPropertiesOrHash()),
storage, effect, control);
}
FieldAccess field_access = {
kTaggedBase,
field_index.offset(),
name,
MaybeHandle<Map>(),
field_type,
MachineType::TypeForRepresentation(field_representation),
kFullWriteBarrier};
bool store_to_constant_field = FLAG_track_constant_fields &&
(access_mode == AccessMode::kStore) &&
access_info.IsDataConstantField();
DCHECK(access_mode == AccessMode::kStore ||
access_mode == AccessMode::kStoreInLiteral);
switch (field_representation) {
case MachineRepresentation::kFloat64: {
value = effect =
graph()->NewNode(simplified()->CheckNumber(VectorSlotPair()), value,
effect, control);
if (!field_index.is_inobject() || field_index.is_hidden_field() ||
!FLAG_unbox_double_fields) {
if (access_info.HasTransitionMap()) {
// Allocate a MutableHeapNumber for the new property.
AllocationBuilder a(jsgraph(), effect, control);
a.Allocate(HeapNumber::kSize, NOT_TENURED, Type::OtherInternal());
a.Store(AccessBuilder::ForMap(),
factory()->mutable_heap_number_map());
a.Store(AccessBuilder::ForHeapNumberValue(), value);
value = effect = a.Finish();
field_access.type = Type::Any();
field_access.machine_type = MachineType::TaggedPointer();
field_access.write_barrier_kind = kPointerWriteBarrier;
} else {
// We just store directly to the MutableHeapNumber.
FieldAccess const storage_access = {kTaggedBase,
field_index.offset(),
name,
MaybeHandle<Map>(),
Type::OtherInternal(),
MachineType::TaggedPointer(),
kPointerWriteBarrier};
storage = effect =
graph()->NewNode(simplified()->LoadField(storage_access),
storage, effect, control);
field_access.offset = HeapNumber::kValueOffset;
field_access.name = MaybeHandle<Name>();
field_access.machine_type = MachineType::Float64();
}
}
if (store_to_constant_field) {
DCHECK(!access_info.HasTransitionMap());
// If the field is constant check that the value we are going
// to store matches current value.
Node* current_value = effect = graph()->NewNode(
simplified()->LoadField(field_access), storage, effect, control);
Node* check = graph()->NewNode(simplified()->NumberEqual(),
current_value, value);
effect = graph()->NewNode(
simplified()->CheckIf(DeoptimizeReason::kWrongValue), check,
effect, control);
return ValueEffectControl(value, effect, control);
}
break;
}
case MachineRepresentation::kTaggedSigned:
case MachineRepresentation::kTaggedPointer:
case MachineRepresentation::kTagged:
if (store_to_constant_field) {
DCHECK(!access_info.HasTransitionMap());
// If the field is constant check that the value we are going
// to store matches current value.
Node* current_value = effect = graph()->NewNode(
simplified()->LoadField(field_access), storage, effect, control);
Node* check = graph()->NewNode(simplified()->ReferenceEqual(),
current_value, value);
effect = graph()->NewNode(
simplified()->CheckIf(DeoptimizeReason::kWrongValue), check,
effect, control);
return ValueEffectControl(value, effect, control);
}
if (field_representation == MachineRepresentation::kTaggedSigned) {
value = effect = graph()->NewNode(
simplified()->CheckSmi(VectorSlotPair()), value, effect, control);
field_access.write_barrier_kind = kNoWriteBarrier;
} else if (field_representation ==
MachineRepresentation::kTaggedPointer) {
// Ensure that {value} is a HeapObject.
value = access_builder.BuildCheckHeapObject(value, &effect, control);
Handle<Map> field_map;
if (access_info.field_map().ToHandle(&field_map)) {
// Emit a map check for the value.
effect = graph()->NewNode(
simplified()->CheckMaps(CheckMapsFlag::kNone,
ZoneHandleSet<Map>(field_map)),
value, effect, control);
}
field_access.write_barrier_kind = kPointerWriteBarrier;
} else {
DCHECK_EQ(MachineRepresentation::kTagged, field_representation);
}
break;
case MachineRepresentation::kNone:
case MachineRepresentation::kBit:
case MachineRepresentation::kWord8:
case MachineRepresentation::kWord16:
case MachineRepresentation::kWord32:
case MachineRepresentation::kWord64:
case MachineRepresentation::kFloat32:
case MachineRepresentation::kSimd128:
UNREACHABLE();
break;
}
// Check if we need to perform a transitioning store.
Handle<Map> transition_map;
if (access_info.transition_map().ToHandle(&transition_map)) {
// Check if we need to grow the properties backing store
// with this transitioning store.
Handle<Map> original_map(Map::cast(transition_map->GetBackPointer()),
isolate());
if (original_map->UnusedPropertyFields() == 0) {
DCHECK(!field_index.is_inobject());
// Reallocate the properties {storage}.
storage = effect = BuildExtendPropertiesBackingStore(
original_map, storage, effect, control);
// Perform the actual store.
effect = graph()->NewNode(simplified()->StoreField(field_access),
storage, value, effect, control);
// Atomically switch to the new properties below.
field_access = AccessBuilder::ForJSObjectPropertiesOrHash();
value = storage;
storage = receiver;
}
effect = graph()->NewNode(
common()->BeginRegion(RegionObservability::kObservable), effect);
effect = graph()->NewNode(
simplified()->StoreField(AccessBuilder::ForMap()), receiver,
jsgraph()->Constant(transition_map), effect, control);
effect = graph()->NewNode(simplified()->StoreField(field_access), storage,
value, effect, control);
effect = graph()->NewNode(common()->FinishRegion(),
jsgraph()->UndefinedConstant(), effect);
} else {
// Regular non-transitioning field store.
effect = graph()->NewNode(simplified()->StoreField(field_access), storage,
value, effect, control);
}
}
return ValueEffectControl(value, effect, control);
}
Reduction JSNativeContextSpecialization::ReduceJSStoreDataPropertyInLiteral(
Node* node) {
DCHECK_EQ(IrOpcode::kJSStoreDataPropertyInLiteral, node->opcode());
FeedbackParameter const& p = FeedbackParameterOf(node->op());
if (!p.feedback().IsValid()) return NoChange();
FeedbackNexus nexus(p.feedback().vector(), p.feedback().slot());
if (nexus.IsUninitialized()) {
return NoChange();
}
if (nexus.ic_state() == MEGAMORPHIC) {
return NoChange();
}
DCHECK_EQ(MONOMORPHIC, nexus.ic_state());
Map* map = nexus.FindFirstMap();
if (map == nullptr) {
// Maps are weakly held in the type feedback vector, we may not have one.
return NoChange();
}
Handle<Map> receiver_map(map, isolate());
if (!Map::TryUpdate(isolate(), receiver_map).ToHandle(&receiver_map))
return NoChange();
Handle<Name> cached_name = handle(
Name::cast(nexus.GetFeedbackExtra()->ToStrongHeapObject()), isolate());
PropertyAccessInfo access_info;
AccessInfoFactory access_info_factory(js_heap_broker(), dependencies(),
native_context().object<Context>(),
graph()->zone());
if (!access_info_factory.ComputePropertyAccessInfo(
receiver_map, cached_name, AccessMode::kStoreInLiteral,
&access_info)) {
return NoChange();
}
Node* receiver = NodeProperties::GetValueInput(node, 0);
Node* effect = NodeProperties::GetEffectInput(node);
Node* control = NodeProperties::GetControlInput(node);
// Monomorphic property access.
PropertyAccessBuilder access_builder(jsgraph(), js_heap_broker(),
dependencies());
receiver = access_builder.BuildCheckHeapObject(receiver, &effect, control);
access_builder.BuildCheckMaps(receiver, &effect, control,
access_info.receiver_maps());
// Ensure that {name} matches the cached name.
Node* name = NodeProperties::GetValueInput(node, 1);
Node* check = graph()->NewNode(simplified()->ReferenceEqual(), name,
jsgraph()->HeapConstant(cached_name));
effect = graph()->NewNode(simplified()->CheckIf(DeoptimizeReason::kWrongName),
check, effect, control);
Node* value = NodeProperties::GetValueInput(node, 2);
Node* context = NodeProperties::GetContextInput(node);
Node* frame_state_lazy = NodeProperties::GetFrameStateInput(node);
// Generate the actual property access.
ValueEffectControl continuation = BuildPropertyAccess(
receiver, value, context, frame_state_lazy, effect, control, cached_name,
nullptr, access_info, AccessMode::kStoreInLiteral);
value = continuation.value();
effect = continuation.effect();
control = continuation.control();
ReplaceWithValue(node, value, effect, control);
return Replace(value);
}
Reduction JSNativeContextSpecialization::ReduceJSStoreInArrayLiteral(
Node* node) {
DCHECK_EQ(IrOpcode::kJSStoreInArrayLiteral, node->opcode());
FeedbackParameter const& p = FeedbackParameterOf(node->op());
Node* const receiver = NodeProperties::GetValueInput(node, 0);
Node* const index = NodeProperties::GetValueInput(node, 1);
Node* const value = NodeProperties::GetValueInput(node, 2);
Node* const effect = NodeProperties::GetEffectInput(node);
// Extract receiver maps from the keyed store IC using the FeedbackNexus.
if (!p.feedback().IsValid()) return NoChange();
FeedbackNexus nexus(p.feedback().vector(), p.feedback().slot());
// Extract the keyed access store mode from the keyed store IC.
KeyedAccessStoreMode store_mode = nexus.GetKeyedAccessStoreMode();
// Extract receiver maps from the {nexus}.
MapHandles receiver_maps;
if (!ExtractReceiverMaps(receiver, effect, nexus, &receiver_maps)) {
return NoChange();
} else if (receiver_maps.empty()) {
if (flags() & kBailoutOnUninitialized) {
return ReduceSoftDeoptimize(
node,
DeoptimizeReason::kInsufficientTypeFeedbackForGenericKeyedAccess);
}
return NoChange();
}
DCHECK(!nexus.IsUninitialized());
DCHECK_EQ(ELEMENT, nexus.GetKeyType());
if (nexus.ic_state() == MEGAMORPHIC) return NoChange();
// Try to lower the element access based on the {receiver_maps}.
return ReduceElementAccess(node, index, value, receiver_maps,
AccessMode::kStoreInLiteral, STANDARD_LOAD,
store_mode);
}
namespace {
ExternalArrayType GetArrayTypeFromElementsKind(ElementsKind kind) {
switch (kind) {
#define TYPED_ARRAY_CASE(Type, type, TYPE, ctype) \
case TYPE##_ELEMENTS: \
return kExternal##Type##Array;
TYPED_ARRAYS(TYPED_ARRAY_CASE)
#undef TYPED_ARRAY_CASE
default:
break;
}
UNREACHABLE();
}
} // namespace
JSNativeContextSpecialization::ValueEffectControl
JSNativeContextSpecialization::BuildElementAccess(
Node* receiver, Node* index, Node* value, Node* effect, Node* control,
ElementAccessInfo const& access_info, AccessMode access_mode,
KeyedAccessLoadMode load_mode, KeyedAccessStoreMode store_mode) {
// TODO(bmeurer): We currently specialize based on elements kind. We should
// also be able to properly support strings and other JSObjects here.
ElementsKind elements_kind = access_info.elements_kind();
MapHandles const& receiver_maps = access_info.receiver_maps();
if (IsFixedTypedArrayElementsKind(elements_kind)) {
Node* buffer;
Node* length;
Node* base_pointer;
Node* external_pointer;
// Check if we can constant-fold information about the {receiver} (i.e.
// for asm.js-like code patterns).
HeapObjectMatcher m(receiver);
if (m.HasValue() && m.Value()->IsJSTypedArray()) {
Handle<JSTypedArray> typed_array = Handle<JSTypedArray>::cast(m.Value());
// Determine the {receiver}s (known) length.
length =
jsgraph()->Constant(static_cast<double>(typed_array->length_value()));
// Check if the {receiver}s buffer was neutered.
buffer = jsgraph()->HeapConstant(typed_array->GetBuffer());
// Load the (known) base and external pointer for the {receiver}. The
// {external_pointer} might be invalid if the {buffer} was neutered, so
// we need to make sure that any access is properly guarded.
base_pointer = jsgraph()->ZeroConstant();
external_pointer = jsgraph()->PointerConstant(
FixedTypedArrayBase::cast(typed_array->elements())
->external_pointer());
} else {
// Load the {receiver}s length.
length = effect = graph()->NewNode(
simplified()->LoadField(AccessBuilder::ForJSTypedArrayLength()),
receiver, effect, control);
// Load the buffer for the {receiver}.
buffer = effect = graph()->NewNode(
simplified()->LoadField(AccessBuilder::ForJSArrayBufferViewBuffer()),
receiver, effect, control);
// Load the elements for the {receiver}.
Node* elements = effect = graph()->NewNode(
simplified()->LoadField(AccessBuilder::ForJSObjectElements()),
receiver, effect, control);
// Load the base pointer for the {receiver}. This will always be Smi
// zero unless we allow on-heap TypedArrays, which is only the case
// for Chrome. Node and Electron both set this limit to 0. Setting
// the base to Smi zero here allows the EffectControlLinearizer to
// optimize away the tricky part of the access later.
if (V8_TYPED_ARRAY_MAX_SIZE_IN_HEAP == 0) {
base_pointer = jsgraph()->ZeroConstant();
} else {
base_pointer = effect = graph()->NewNode(
simplified()->LoadField(
AccessBuilder::ForFixedTypedArrayBaseBasePointer()),
elements, effect, control);
}
// Load the external pointer for the {receiver}s {elements}.
external_pointer = effect = graph()->NewNode(
simplified()->LoadField(
AccessBuilder::ForFixedTypedArrayBaseExternalPointer()),
elements, effect, control);
}
// See if we can skip the neutering check.
if (isolate()->IsArrayBufferNeuteringIntact()) {
// Add a code dependency so we are deoptimized in case an ArrayBuffer
// gets neutered.
dependencies()->DependOnProtector(PropertyCellRef(
js_heap_broker(), factory()->array_buffer_neutering_protector()));
} else {
// Default to zero if the {receiver}s buffer was neutered.
Node* check = effect = graph()->NewNode(
simplified()->ArrayBufferWasNeutered(), buffer, effect, control);
length = graph()->NewNode(
common()->Select(MachineRepresentation::kTagged, BranchHint::kFalse),
check, jsgraph()->ZeroConstant(), length);
}
if (load_mode == LOAD_IGNORE_OUT_OF_BOUNDS ||
store_mode == STORE_NO_TRANSITION_IGNORE_OUT_OF_BOUNDS) {
// Only check that the {index} is in SignedSmall range. We do the actual
// bounds check below and just skip the property access if it's out of
// bounds for the {receiver}.
index = effect = graph()->NewNode(
simplified()->CheckSmi(VectorSlotPair()), index, effect, control);
// Cast the {index} to Unsigned32 range, so that the bounds checks
// below are performed on unsigned values, which means that all the
// Negative32 values are treated as out-of-bounds.
index = graph()->NewNode(simplified()->NumberToUint32(), index);
} else {
// Check that the {index} is in the valid range for the {receiver}.
index = effect =
graph()->NewNode(simplified()->CheckBounds(VectorSlotPair()), index,
length, effect, control);
}
// Access the actual element.
ExternalArrayType external_array_type =
GetArrayTypeFromElementsKind(elements_kind);
switch (access_mode) {
case AccessMode::kLoad: {
// Check if we can return undefined for out-of-bounds loads.
if (load_mode == LOAD_IGNORE_OUT_OF_BOUNDS) {
Node* check =
graph()->NewNode(simplified()->NumberLessThan(), index, length);
Node* branch = graph()->NewNode(
common()->Branch(BranchHint::kTrue,
IsSafetyCheck::kCriticalSafetyCheck),
check, control);
Node* if_true = graph()->NewNode(common()->IfTrue(), branch);
Node* etrue = effect;
Node* vtrue;
{
// Perform the actual load
vtrue = etrue = graph()->NewNode(
simplified()->LoadTypedElement(external_array_type), buffer,
base_pointer, external_pointer, index, etrue, if_true);
}
Node* if_false = graph()->NewNode(common()->IfFalse(), branch);
Node* efalse = effect;
Node* vfalse;
{
// Materialize undefined for out-of-bounds loads.
vfalse = jsgraph()->UndefinedConstant();
}
control = graph()->NewNode(common()->Merge(2), if_true, if_false);
effect =
graph()->NewNode(common()->EffectPhi(2), etrue, efalse, control);
value =
graph()->NewNode(common()->Phi(MachineRepresentation::kTagged, 2),
vtrue, vfalse, control);
} else {
// Perform the actual load.
value = effect = graph()->NewNode(
simplified()->LoadTypedElement(external_array_type), buffer,
base_pointer, external_pointer, index, effect, control);
}
break;
}
case AccessMode::kStoreInLiteral:
UNREACHABLE();
break;
case AccessMode::kStore: {
// Ensure that the {value} is actually a Number or an Oddball,
// and truncate it to a Number appropriately.
value = effect = graph()->NewNode(
simplified()->SpeculativeToNumber(
NumberOperationHint::kNumberOrOddball, VectorSlotPair()),
value, effect, control);
// Introduce the appropriate truncation for {value}. Currently we
// only need to do this for ClamedUint8Array {receiver}s, as the
// other truncations are implicit in the StoreTypedElement, but we
// might want to change that at some point.
if (external_array_type == kExternalUint8ClampedArray) {
value = graph()->NewNode(simplified()->NumberToUint8Clamped(), value);
}
// Check if we can skip the out-of-bounds store.
if (store_mode == STORE_NO_TRANSITION_IGNORE_OUT_OF_BOUNDS) {
Node* check =
graph()->NewNode(simplified()->NumberLessThan(), index, length);
Node* branch = graph()->NewNode(common()->Branch(BranchHint::kTrue),
check, control);
Node* if_true = graph()->NewNode(common()->IfTrue(), branch);
Node* etrue = effect;
{
// Perform the actual store.
etrue = graph()->NewNode(
simplified()->StoreTypedElement(external_array_type), buffer,
base_pointer, external_pointer, index, value, etrue, if_true);
}
Node* if_false = graph()->NewNode(common()->IfFalse(), branch);
Node* efalse = effect;
{
// Just ignore the out-of-bounds write.
}
control = graph()->NewNode(common()->Merge(2), if_true, if_false);
effect =
graph()->NewNode(common()->EffectPhi(2), etrue, efalse, control);
} else {
// Perform the actual store
effect = graph()->NewNode(
simplified()->StoreTypedElement(external_array_type), buffer,
base_pointer, external_pointer, index, value, effect, control);
}
break;
}
}
} else {
// Load the elements for the {receiver}.
Node* elements = effect = graph()->NewNode(
simplified()->LoadField(AccessBuilder::ForJSObjectElements()), receiver,
effect, control);
// Don't try to store to a copy-on-write backing store (unless supported by
// the store mode).
if (access_mode == AccessMode::kStore &&
IsSmiOrObjectElementsKind(elements_kind) &&
!IsCOWHandlingStoreMode(store_mode)) {
effect = graph()->NewNode(
simplified()->CheckMaps(