v8/src/type-info.cc

479 lines
16 KiB
C++

// Copyright 2012 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/v8.h"
#include "src/ast.h"
#include "src/code-stubs.h"
#include "src/compiler.h"
#include "src/ic/ic.h"
#include "src/ic/stub-cache.h"
#include "src/type-info.h"
namespace v8 {
namespace internal {
TypeFeedbackOracle::TypeFeedbackOracle(
Handle<Code> code, Handle<TypeFeedbackVector> feedback_vector,
Handle<Context> native_context, Zone* zone)
: native_context_(native_context), zone_(zone) {
BuildDictionary(code);
DCHECK(dictionary_->IsDictionary());
// We make a copy of the feedback vector because a GC could clear
// the type feedback info contained therein.
// TODO(mvstanton): revisit the decision to copy when we weakly
// traverse the feedback vector at GC time.
feedback_vector_ = TypeFeedbackVector::Copy(isolate(), feedback_vector);
}
static uint32_t IdToKey(TypeFeedbackId ast_id) {
return static_cast<uint32_t>(ast_id.ToInt());
}
Handle<Object> TypeFeedbackOracle::GetInfo(TypeFeedbackId ast_id) {
int entry = dictionary_->FindEntry(IdToKey(ast_id));
if (entry != UnseededNumberDictionary::kNotFound) {
Object* value = dictionary_->ValueAt(entry);
if (value->IsCell()) {
Cell* cell = Cell::cast(value);
return Handle<Object>(cell->value(), isolate());
} else {
return Handle<Object>(value, isolate());
}
}
return Handle<Object>::cast(isolate()->factory()->undefined_value());
}
Handle<Object> TypeFeedbackOracle::GetInfo(FeedbackVectorSlot slot) {
DCHECK(slot.ToInt() >= 0 && slot.ToInt() < feedback_vector_->length());
Object* obj = feedback_vector_->Get(slot);
if (!obj->IsJSFunction() ||
!CanRetainOtherContext(JSFunction::cast(obj), *native_context_)) {
return Handle<Object>(obj, isolate());
}
return Handle<Object>::cast(isolate()->factory()->undefined_value());
}
Handle<Object> TypeFeedbackOracle::GetInfo(FeedbackVectorICSlot slot) {
DCHECK(slot.ToInt() >= 0 && slot.ToInt() < feedback_vector_->length());
Object* obj = feedback_vector_->Get(slot);
if (!obj->IsJSFunction() ||
!CanRetainOtherContext(JSFunction::cast(obj), *native_context_)) {
return Handle<Object>(obj, isolate());
}
return Handle<Object>::cast(isolate()->factory()->undefined_value());
}
bool TypeFeedbackOracle::LoadIsUninitialized(TypeFeedbackId id) {
Handle<Object> maybe_code = GetInfo(id);
if (maybe_code->IsCode()) {
Handle<Code> code = Handle<Code>::cast(maybe_code);
return code->is_inline_cache_stub() && code->ic_state() == UNINITIALIZED;
}
return false;
}
bool TypeFeedbackOracle::StoreIsUninitialized(TypeFeedbackId ast_id) {
Handle<Object> maybe_code = GetInfo(ast_id);
if (!maybe_code->IsCode()) return false;
Handle<Code> code = Handle<Code>::cast(maybe_code);
return code->ic_state() == UNINITIALIZED;
}
bool TypeFeedbackOracle::CallIsMonomorphic(FeedbackVectorICSlot slot) {
Handle<Object> value = GetInfo(slot);
return value->IsAllocationSite() || value->IsJSFunction();
}
bool TypeFeedbackOracle::CallNewIsMonomorphic(FeedbackVectorSlot slot) {
Handle<Object> info = GetInfo(slot);
return FLAG_pretenuring_call_new
? info->IsJSFunction()
: info->IsAllocationSite() || info->IsJSFunction();
}
byte TypeFeedbackOracle::ForInType(FeedbackVectorSlot feedback_vector_slot) {
Handle<Object> value = GetInfo(feedback_vector_slot);
return value.is_identical_to(
TypeFeedbackVector::UninitializedSentinel(isolate()))
? ForInStatement::FAST_FOR_IN
: ForInStatement::SLOW_FOR_IN;
}
void TypeFeedbackOracle::GetStoreModeAndKeyType(
TypeFeedbackId ast_id, KeyedAccessStoreMode* store_mode,
IcCheckType* key_type) {
Handle<Object> maybe_code = GetInfo(ast_id);
if (maybe_code->IsCode()) {
Handle<Code> code = Handle<Code>::cast(maybe_code);
if (code->kind() == Code::KEYED_STORE_IC) {
ExtraICState extra_ic_state = code->extra_ic_state();
*store_mode = KeyedStoreIC::GetKeyedAccessStoreMode(extra_ic_state);
*key_type = KeyedStoreIC::GetKeyType(extra_ic_state);
return;
}
}
*store_mode = STANDARD_STORE;
*key_type = ELEMENT;
}
Handle<JSFunction> TypeFeedbackOracle::GetCallTarget(
FeedbackVectorICSlot slot) {
Handle<Object> info = GetInfo(slot);
if (info->IsAllocationSite()) {
return Handle<JSFunction>(isolate()->native_context()->array_function());
}
return Handle<JSFunction>::cast(info);
}
Handle<JSFunction> TypeFeedbackOracle::GetCallNewTarget(
FeedbackVectorSlot slot) {
Handle<Object> info = GetInfo(slot);
if (FLAG_pretenuring_call_new || info->IsJSFunction()) {
return Handle<JSFunction>::cast(info);
}
DCHECK(info->IsAllocationSite());
return Handle<JSFunction>(isolate()->native_context()->array_function());
}
Handle<AllocationSite> TypeFeedbackOracle::GetCallAllocationSite(
FeedbackVectorICSlot slot) {
Handle<Object> info = GetInfo(slot);
if (info->IsAllocationSite()) {
return Handle<AllocationSite>::cast(info);
}
return Handle<AllocationSite>::null();
}
Handle<AllocationSite> TypeFeedbackOracle::GetCallNewAllocationSite(
FeedbackVectorSlot slot) {
Handle<Object> info = GetInfo(slot);
if (FLAG_pretenuring_call_new || info->IsAllocationSite()) {
return Handle<AllocationSite>::cast(info);
}
return Handle<AllocationSite>::null();
}
bool TypeFeedbackOracle::LoadIsBuiltin(
TypeFeedbackId id, Builtins::Name builtin) {
return *GetInfo(id) == isolate()->builtins()->builtin(builtin);
}
void TypeFeedbackOracle::CompareType(TypeFeedbackId id,
Type** left_type,
Type** right_type,
Type** combined_type) {
Handle<Object> info = GetInfo(id);
if (!info->IsCode()) {
// For some comparisons we don't have ICs, e.g. LiteralCompareTypeof.
*left_type = *right_type = *combined_type = Type::None(zone());
return;
}
Handle<Code> code = Handle<Code>::cast(info);
Handle<Map> map;
Map* raw_map = code->FindFirstMap();
if (raw_map != NULL) {
if (Map::TryUpdate(handle(raw_map)).ToHandle(&map) &&
CanRetainOtherContext(*map, *native_context_)) {
map = Handle<Map>::null();
}
}
if (code->is_compare_ic_stub()) {
CompareICStub stub(code->stub_key(), isolate());
*left_type = CompareICState::StateToType(zone(), stub.left());
*right_type = CompareICState::StateToType(zone(), stub.right());
*combined_type = CompareICState::StateToType(zone(), stub.state(), map);
} else if (code->is_compare_nil_ic_stub()) {
CompareNilICStub stub(isolate(), code->extra_ic_state());
*combined_type = stub.GetType(zone(), map);
*left_type = *right_type = stub.GetInputType(zone(), map);
}
}
void TypeFeedbackOracle::BinaryType(TypeFeedbackId id,
Type** left,
Type** right,
Type** result,
Maybe<int>* fixed_right_arg,
Handle<AllocationSite>* allocation_site,
Token::Value op) {
Handle<Object> object = GetInfo(id);
if (!object->IsCode()) {
// For some binary ops we don't have ICs, e.g. Token::COMMA, but for the
// operations covered by the BinaryOpIC we should always have them.
DCHECK(op < BinaryOpICState::FIRST_TOKEN ||
op > BinaryOpICState::LAST_TOKEN);
*left = *right = *result = Type::None(zone());
*fixed_right_arg = Maybe<int>();
*allocation_site = Handle<AllocationSite>::null();
return;
}
Handle<Code> code = Handle<Code>::cast(object);
DCHECK_EQ(Code::BINARY_OP_IC, code->kind());
BinaryOpICState state(isolate(), code->extra_ic_state());
DCHECK_EQ(op, state.op());
*left = state.GetLeftType(zone());
*right = state.GetRightType(zone());
*result = state.GetResultType(zone());
*fixed_right_arg = state.fixed_right_arg();
AllocationSite* first_allocation_site = code->FindFirstAllocationSite();
if (first_allocation_site != NULL) {
*allocation_site = handle(first_allocation_site);
} else {
*allocation_site = Handle<AllocationSite>::null();
}
}
Type* TypeFeedbackOracle::CountType(TypeFeedbackId id) {
Handle<Object> object = GetInfo(id);
if (!object->IsCode()) return Type::None(zone());
Handle<Code> code = Handle<Code>::cast(object);
DCHECK_EQ(Code::BINARY_OP_IC, code->kind());
BinaryOpICState state(isolate(), code->extra_ic_state());
return state.GetLeftType(zone());
}
void TypeFeedbackOracle::PropertyReceiverTypes(TypeFeedbackId id,
Handle<String> name,
SmallMapList* receiver_types) {
receiver_types->Clear();
Code::Flags flags = Code::ComputeHandlerFlags(Code::LOAD_IC);
CollectReceiverTypes(id, name, flags, receiver_types);
}
void TypeFeedbackOracle::KeyedPropertyReceiverTypes(
TypeFeedbackId id, SmallMapList* receiver_types, bool* is_string) {
receiver_types->Clear();
CollectReceiverTypes(id, receiver_types);
// Are all the receiver maps string maps?
bool all_strings = receiver_types->length() > 0;
for (int i = 0; i < receiver_types->length(); i++) {
all_strings &= receiver_types->at(i)->IsStringMap();
}
*is_string = all_strings;
}
void TypeFeedbackOracle::AssignmentReceiverTypes(
TypeFeedbackId id, Handle<String> name, SmallMapList* receiver_types) {
receiver_types->Clear();
Code::Flags flags = Code::ComputeHandlerFlags(Code::STORE_IC);
CollectReceiverTypes(id, name, flags, receiver_types);
}
void TypeFeedbackOracle::KeyedAssignmentReceiverTypes(
TypeFeedbackId id, SmallMapList* receiver_types,
KeyedAccessStoreMode* store_mode, IcCheckType* key_type) {
receiver_types->Clear();
CollectReceiverTypes(id, receiver_types);
GetStoreModeAndKeyType(id, store_mode, key_type);
}
void TypeFeedbackOracle::CountReceiverTypes(TypeFeedbackId id,
SmallMapList* receiver_types) {
receiver_types->Clear();
CollectReceiverTypes(id, receiver_types);
}
void TypeFeedbackOracle::CollectReceiverTypes(TypeFeedbackId ast_id,
Handle<String> name,
Code::Flags flags,
SmallMapList* types) {
Handle<Object> object = GetInfo(ast_id);
if (object->IsUndefined() || object->IsSmi()) return;
DCHECK(object->IsCode());
Handle<Code> code(Handle<Code>::cast(object));
if (FLAG_collect_megamorphic_maps_from_stub_cache &&
code->ic_state() == MEGAMORPHIC) {
types->Reserve(4, zone());
isolate()->stub_cache()->CollectMatchingMaps(
types, name, flags, native_context_, zone());
} else {
CollectReceiverTypes(ast_id, types);
}
}
// Check if a map originates from a given native context. We use this
// information to filter out maps from different context to avoid
// retaining objects from different tabs in Chrome via optimized code.
bool TypeFeedbackOracle::CanRetainOtherContext(Map* map,
Context* native_context) {
Object* constructor = NULL;
while (!map->prototype()->IsNull()) {
constructor = map->constructor();
if (!constructor->IsNull()) {
// If the constructor is not null or a JSFunction, we have to
// conservatively assume that it may retain a native context.
if (!constructor->IsJSFunction()) return true;
// Check if the constructor directly references a foreign context.
if (CanRetainOtherContext(JSFunction::cast(constructor),
native_context)) {
return true;
}
}
map = HeapObject::cast(map->prototype())->map();
}
constructor = map->constructor();
if (constructor->IsNull()) return false;
JSFunction* function = JSFunction::cast(constructor);
return CanRetainOtherContext(function, native_context);
}
bool TypeFeedbackOracle::CanRetainOtherContext(JSFunction* function,
Context* native_context) {
return function->context()->global_object() != native_context->global_object()
&& function->context()->global_object() != native_context->builtins();
}
void TypeFeedbackOracle::CollectReceiverTypes(TypeFeedbackId ast_id,
SmallMapList* types) {
Handle<Object> object = GetInfo(ast_id);
if (!object->IsCode()) return;
Handle<Code> code = Handle<Code>::cast(object);
MapHandleList maps;
if (code->ic_state() == MONOMORPHIC) {
Map* map = code->FindFirstMap();
if (map != NULL) maps.Add(handle(map));
} else if (code->ic_state() == POLYMORPHIC) {
code->FindAllMaps(&maps);
} else {
return;
}
types->Reserve(maps.length(), zone());
for (int i = 0; i < maps.length(); i++) {
Handle<Map> map(maps.at(i));
if (!CanRetainOtherContext(*map, *native_context_)) {
types->AddMapIfMissing(map, zone());
}
}
}
byte TypeFeedbackOracle::ToBooleanTypes(TypeFeedbackId id) {
Handle<Object> object = GetInfo(id);
return object->IsCode() ? Handle<Code>::cast(object)->to_boolean_state() : 0;
}
// Things are a bit tricky here: The iterator for the RelocInfos and the infos
// themselves are not GC-safe, so we first get all infos, then we create the
// dictionary (possibly triggering GC), and finally we relocate the collected
// infos before we process them.
void TypeFeedbackOracle::BuildDictionary(Handle<Code> code) {
DisallowHeapAllocation no_allocation;
ZoneList<RelocInfo> infos(16, zone());
HandleScope scope(isolate());
GetRelocInfos(code, &infos);
CreateDictionary(code, &infos);
ProcessRelocInfos(&infos);
// Allocate handle in the parent scope.
dictionary_ = scope.CloseAndEscape(dictionary_);
}
void TypeFeedbackOracle::GetRelocInfos(Handle<Code> code,
ZoneList<RelocInfo>* infos) {
int mask = RelocInfo::ModeMask(RelocInfo::CODE_TARGET_WITH_ID);
for (RelocIterator it(*code, mask); !it.done(); it.next()) {
infos->Add(*it.rinfo(), zone());
}
}
void TypeFeedbackOracle::CreateDictionary(Handle<Code> code,
ZoneList<RelocInfo>* infos) {
AllowHeapAllocation allocation_allowed;
Code* old_code = *code;
dictionary_ = UnseededNumberDictionary::New(isolate(), infos->length());
RelocateRelocInfos(infos, old_code, *code);
}
void TypeFeedbackOracle::RelocateRelocInfos(ZoneList<RelocInfo>* infos,
Code* old_code,
Code* new_code) {
for (int i = 0; i < infos->length(); i++) {
RelocInfo* info = &(*infos)[i];
info->set_host(new_code);
info->set_pc(new_code->instruction_start() +
(info->pc() - old_code->instruction_start()));
}
}
void TypeFeedbackOracle::ProcessRelocInfos(ZoneList<RelocInfo>* infos) {
for (int i = 0; i < infos->length(); i++) {
RelocInfo reloc_entry = (*infos)[i];
Address target_address = reloc_entry.target_address();
TypeFeedbackId ast_id =
TypeFeedbackId(static_cast<unsigned>((*infos)[i].data()));
Code* target = Code::GetCodeFromTargetAddress(target_address);
switch (target->kind()) {
case Code::LOAD_IC:
case Code::STORE_IC:
case Code::KEYED_LOAD_IC:
case Code::KEYED_STORE_IC:
case Code::BINARY_OP_IC:
case Code::COMPARE_IC:
case Code::TO_BOOLEAN_IC:
case Code::COMPARE_NIL_IC:
SetInfo(ast_id, target);
break;
default:
break;
}
}
}
void TypeFeedbackOracle::SetInfo(TypeFeedbackId ast_id, Object* target) {
DCHECK(dictionary_->FindEntry(IdToKey(ast_id)) ==
UnseededNumberDictionary::kNotFound);
// Dictionary has been allocated with sufficient size for all elements.
DisallowHeapAllocation no_need_to_resize_dictionary;
HandleScope scope(isolate());
USE(UnseededNumberDictionary::AtNumberPut(
dictionary_, IdToKey(ast_id), handle(target, isolate())));
}
} } // namespace v8::internal