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[stubs] KeyedLoadIC_Generic: prototype chain lookup support (reland)

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Performing lookups on the prototype chain in the stub avoids a
bunch of slow-path runtime calls. For now, only receivers with
dictionary-mode properties do this; fast-mode receivers will follow
if it's beneficial.

(previously landed as r42751 / 82e10f5fba)

Review-Url: https://codereview.chromium.org/2652213003
Cr-Commit-Position: refs/heads/master@{#42785}
This commit is contained in:
jkummerow 2017-01-30 10:56:19 -08:00 committed by Commit bot
parent dc85f4c833
commit e42da75c9e
1 changed files with 50 additions and 2 deletions
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52
src/ic/accessor-assembler.cc
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@ -1403,7 +1403,8 @@ void AccessorAssembler::KeyedLoadICGeneric(const LoadICParameters* p) {
Variable var_value(this, MachineRepresentation::kTagged);
Label if_index(this), if_unique_name(this), if_element_hole(this),
if_oob(this), slow(this), stub_cache_miss(this),
if_property_dictionary(this), if_found_on_receiver(this);
if_property_dictionary(this), if_found_on_receiver(this),
lookup_prototype_chain(this);
Node* receiver = p->receiver;
GotoIf(TaggedIsSmi(receiver), &slow);
@ -1528,7 +1529,8 @@ void AccessorAssembler::KeyedLoadICGeneric(const LoadICParameters* p) {
Variable var_name_index(this, MachineType::PointerRepresentation());
Label dictionary_found(this, &var_name_index);
NameDictionaryLookup<NameDictionary>(properties, key, &dictionary_found,
&var_name_index, &slow);
&var_name_index,
&lookup_prototype_chain);
Bind(&dictionary_found);
{
LoadPropertyFromNameDictionary(properties, var_name_index.value(),
@ -1545,6 +1547,52 @@ void AccessorAssembler::KeyedLoadICGeneric(const LoadICParameters* p) {
Return(value);
}
Bind(&lookup_prototype_chain);
{
Variable var_holder_map(this, MachineRepresentation::kTagged);
Variable var_holder_instance_type(this, MachineRepresentation::kWord32);
Label return_undefined(this);
Variable* merged_variables[] = {&var_holder_map, &var_holder_instance_type};
Label loop(this, arraysize(merged_variables), merged_variables);
var_holder_map.Bind(receiver_map);
var_holder_instance_type.Bind(instance_type);
// Private symbols must not be looked up on the prototype chain.
GotoIf(IsPrivateSymbol(var_unique.value()), &return_undefined);
Goto(&loop);
Bind(&loop);
{
// Bailout if it can be an integer indexed exotic case.
GotoIf(Word32Equal(var_holder_instance_type.value(),
Int32Constant(JS_TYPED_ARRAY_TYPE)),
&slow);
Node* proto = LoadMapPrototype(var_holder_map.value());
GotoIf(WordEqual(proto, NullConstant()), &return_undefined);
Node* proto_map = LoadMap(proto);
Node* proto_instance_type = LoadMapInstanceType(proto_map);
var_holder_map.Bind(proto_map);
var_holder_instance_type.Bind(proto_instance_type);
Label next_proto(this), return_value(this, &var_value), goto_slow(this);
TryGetOwnProperty(p->context, receiver, proto, proto_map,
proto_instance_type, var_unique.value(), &return_value,
&var_value, &next_proto, &goto_slow);
// This trampoline and the next are required to appease Turbofan's
// variable merging.
Bind(&next_proto);
Goto(&loop);
Bind(&goto_slow);
Goto(&slow);
Bind(&return_value);
Return(var_value.value());
}
Bind(&return_undefined);
Return(UndefinedConstant());
}
Bind(&slow);
{
Comment("KeyedLoadGeneric_slow");