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// Copyright 2017 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/ic/handler-configuration.h"
#include "src/code-stubs.h"
#include "src/ic/handler-configuration-inl.h"
#include "src/objects/data-handler-inl.h"
#include "src/objects/maybe-object.h"
#include "src/transitions.h"
namespace v8 {
namespace internal {
namespace {
template <typename BitField>
Handle<Smi> SetBitFieldValue(Isolate* isolate, Handle<Smi> smi_handler,
typename BitField::FieldType value) {
int config = smi_handler->value();
config = BitField::update(config, true);
return handle(Smi::FromInt(config), isolate);
}
// TODO(ishell): Remove templatezation once we move common bits from
// Load/StoreHandler to the base class.
template <typename ICHandler, bool fill_handler = true>
int InitPrototypeChecksImpl(Isolate* isolate, Handle<ICHandler> handler,
Handle<Smi>* smi_handler, Handle<Map> receiver_map,
Handle<JSReceiver> holder, MaybeObjectHandle data1,
MaybeObjectHandle maybe_data2) {
int checks_count = 0;
// Holder-is-receiver case itself does not add entries unless there is an
// optional data2 value provided.
if (receiver_map->IsPrimitiveMap() ||
receiver_map->is_access_check_needed()) {
DCHECK(!receiver_map->IsJSGlobalObjectMap());
// The validity cell check for primitive and global proxy receivers does
// not guarantee that certain native context ever had access to other
// native context. However, a handler created for one native context could
// be used in other native context through the megamorphic stub cache.
// So we record the original native context to which this handler
// corresponds.
if (fill_handler) {
Handle<Context> native_context = isolate->native_context();
handler->set_data2(HeapObjectReference::Weak(*native_context));
} else {
// Enable access checks on receiver.
typedef typename ICHandler::DoAccessCheckOnReceiverBits Bit;
*smi_handler = SetBitFieldValue<Bit>(isolate, *smi_handler, true);
}
checks_count++;
} else if (receiver_map->is_dictionary_map() &&
!receiver_map->IsJSGlobalObjectMap()) {
if (!fill_handler) {
// Enable lookup on receiver.
typedef typename ICHandler::LookupOnReceiverBits Bit;
*smi_handler = SetBitFieldValue<Bit>(isolate, *smi_handler, true);
}
}
if (fill_handler) {
handler->set_data1(*data1);
}
if (!maybe_data2.is_null()) {
if (fill_handler) {
// This value will go either to data2 or data3 slot depending on whether
// data2 slot is already occupied by native context.
if (checks_count == 0) {
handler->set_data2(*maybe_data2);
} else {
DCHECK_EQ(1, checks_count);
handler->set_data3(*maybe_data2);
}
}
checks_count++;
}
return checks_count;
}
// Returns 0 if the validity cell check is enough to ensure that the
// prototype chain from |receiver_map| till |holder| did not change.
// If the |holder| is an empty handle then the full prototype chain is
// checked.
// Returns -1 if the handler has to be compiled or the number of prototype
// checks otherwise.
template <typename ICHandler>
int GetPrototypeCheckCount(
Isolate* isolate, Handle<Smi>* smi_handler, Handle<Map> receiver_map,
Handle<JSReceiver> holder, MaybeObjectHandle data1,
MaybeObjectHandle maybe_data2 = MaybeObjectHandle()) {
DCHECK_NOT_NULL(smi_handler);
return InitPrototypeChecksImpl<ICHandler, false>(isolate, Handle<ICHandler>(),
smi_handler, receiver_map,
holder, data1, maybe_data2);
}
template <typename ICHandler>
void InitPrototypeChecks(Isolate* isolate, Handle<ICHandler> handler,
Handle<Map> receiver_map, Handle<JSReceiver> holder,
MaybeObjectHandle data1,
MaybeObjectHandle maybe_data2 = MaybeObjectHandle()) {
InitPrototypeChecksImpl<ICHandler, true>(
isolate, handler, nullptr, receiver_map, holder, data1, maybe_data2);
}
} // namespace
// static
Handle<Object> LoadHandler::LoadFromPrototype(Isolate* isolate,
Handle<Map> receiver_map,
Handle<JSReceiver> holder,
Handle<Smi> smi_handler,
MaybeObjectHandle maybe_data1,
MaybeObjectHandle maybe_data2) {
MaybeObjectHandle data1;
if (maybe_data1.is_null()) {
data1 = MaybeObjectHandle::Weak(holder);
} else {
data1 = maybe_data1;
}
int checks_count = GetPrototypeCheckCount<LoadHandler>(
isolate, &smi_handler, receiver_map, holder, data1, maybe_data2);
Handle<Object> validity_cell =
Map::GetOrCreatePrototypeChainValidityCell(receiver_map, isolate);
int data_count = 1 + checks_count;
Handle<LoadHandler> handler = isolate->factory()->NewLoadHandler(data_count);
handler->set_smi_handler(*smi_handler);
handler->set_validity_cell(*validity_cell);
InitPrototypeChecks(isolate, handler, receiver_map, holder, data1,
maybe_data2);
return handler;
}
// static
Handle<Object> LoadHandler::LoadFullChain(Isolate* isolate,
Handle<Map> receiver_map,
MaybeObjectHandle holder,
Handle<Smi> smi_handler) {
Handle<JSReceiver> end; // null handle, means full prototype chain lookup.
MaybeObjectHandle data1 = holder;
int checks_count = GetPrototypeCheckCount<LoadHandler>(
isolate, &smi_handler, receiver_map, end, data1);
Handle<Object> validity_cell =
Map::GetOrCreatePrototypeChainValidityCell(receiver_map, isolate);
if (validity_cell->IsSmi()) {
DCHECK_EQ(0, checks_count);
// Lookup on receiver isn't supported in case of a simple smi handler.
if (!LookupOnReceiverBits::decode(smi_handler->value())) return smi_handler;
}
int data_count = 1 + checks_count;
Handle<LoadHandler> handler = isolate->factory()->NewLoadHandler(data_count);
handler->set_smi_handler(*smi_handler);
handler->set_validity_cell(*validity_cell);
InitPrototypeChecks(isolate, handler, receiver_map, end, data1);
return handler;
}
// static
KeyedAccessLoadMode LoadHandler::GetKeyedAccessLoadMode(MaybeObject* handler) {
DisallowHeapAllocation no_gc;
if (handler->IsSmi()) {
int const raw_handler = Smi::cast(handler->ToSmi())->value();
Kind const kind = KindBits::decode(raw_handler);
if ((kind == kElement || kind == kIndexedString) &&
AllowOutOfBoundsBits::decode(raw_handler)) {
return LOAD_IGNORE_OUT_OF_BOUNDS;
}
}
return STANDARD_LOAD;
}
// static
Handle<Object> StoreHandler::StoreElementTransition(
Isolate* isolate, Handle<Map> receiver_map, Handle<Map> transition,
KeyedAccessStoreMode store_mode) {
bool is_js_array = receiver_map->instance_type() == JS_ARRAY_TYPE;
ElementsKind elements_kind = receiver_map->elements_kind();
Handle<Code> stub = ElementsTransitionAndStoreStub(
isolate, elements_kind, transition->elements_kind(),
is_js_array, store_mode)
.GetCode();
Handle<Object> validity_cell =
Map::GetOrCreatePrototypeChainValidityCell(receiver_map, isolate);
Handle<StoreHandler> handler = isolate->factory()->NewStoreHandler(1);
handler->set_smi_handler(*stub);
handler->set_validity_cell(*validity_cell);
handler->set_data1(HeapObjectReference::Weak(*transition));
return handler;
}
MaybeObjectHandle StoreHandler::StoreTransition(Isolate* isolate,
Handle<Map> transition_map) {
bool is_dictionary_map = transition_map->is_dictionary_map();
#ifdef DEBUG
if (!is_dictionary_map) {
int descriptor = transition_map->LastAdded();
Handle<DescriptorArray> descriptors(transition_map->instance_descriptors(),
isolate);
PropertyDetails details = descriptors->GetDetails(descriptor);
if (descriptors->GetKey(descriptor)->IsPrivate()) {
DCHECK_EQ(DONT_ENUM, details.attributes());
} else {
DCHECK_EQ(NONE, details.attributes());
}
Representation representation = details.representation();
DCHECK(!representation.IsNone());
}
#endif
// Declarative handlers don't support access checks.
DCHECK(!transition_map->is_access_check_needed());
// Get validity cell value if it is necessary for the handler.
Handle<Object> validity_cell;
if (is_dictionary_map || !transition_map->IsPrototypeValidityCellValid()) {
validity_cell =
Map::GetOrCreatePrototypeChainValidityCell(transition_map, isolate);
}
if (is_dictionary_map) {
DCHECK(!transition_map->IsJSGlobalObjectMap());
Handle<StoreHandler> handler = isolate->factory()->NewStoreHandler(0);
// Store normal with enabled lookup on receiver.
int config = KindBits::encode(kNormal) | LookupOnReceiverBits::encode(true);
handler->set_smi_handler(Smi::FromInt(config));
handler->set_validity_cell(*validity_cell);
return MaybeObjectHandle(handler);
} else {
// Ensure the transition map contains a valid prototype validity cell.
if (!validity_cell.is_null()) {
transition_map->set_prototype_validity_cell(*validity_cell);
}
return MaybeObjectHandle::Weak(transition_map);
}
}
// static
Handle<Object> StoreHandler::StoreThroughPrototype(
Isolate* isolate, Handle<Map> receiver_map, Handle<JSReceiver> holder,
Handle<Smi> smi_handler, MaybeObjectHandle maybe_data1,
MaybeObjectHandle maybe_data2) {
MaybeObjectHandle data1;
if (maybe_data1.is_null()) {
data1 = MaybeObjectHandle::Weak(holder);
} else {
data1 = maybe_data1;
}
int checks_count = GetPrototypeCheckCount<StoreHandler>(
isolate, &smi_handler, receiver_map, holder, data1, maybe_data2);
Handle<Object> validity_cell =
Map::GetOrCreatePrototypeChainValidityCell(receiver_map, isolate);
DCHECK_IMPLIES(validity_cell->IsSmi(), checks_count == 0);
int data_count = 1 + checks_count;
Handle<StoreHandler> handler =
isolate->factory()->NewStoreHandler(data_count);
handler->set_smi_handler(*smi_handler);
handler->set_validity_cell(*validity_cell);
InitPrototypeChecks(isolate, handler, receiver_map, holder, data1,
maybe_data2);
return handler;
}
// static
MaybeObjectHandle StoreHandler::StoreGlobal(Handle<PropertyCell> cell) {
return MaybeObjectHandle::Weak(cell);
}
// static
Handle<Object> StoreHandler::StoreProxy(Isolate* isolate,
Handle<Map> receiver_map,
Handle<JSProxy> proxy,
Handle<JSReceiver> receiver) {
Handle<Smi> smi_handler = StoreProxy(isolate);
if (receiver.is_identical_to(proxy)) return smi_handler;
return StoreThroughPrototype(isolate, receiver_map, proxy, smi_handler,
MaybeObjectHandle::Weak(proxy));
}
} // namespace internal
} // namespace v8
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