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// 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/accessors.h"
#include "src/api.h"
#include "src/arguments.h"
#include "src/base/bits.h"
#include "src/codegen.h"
#include "src/conversions.h"
#include "src/execution.h"
#include "src/ic/call-optimization.h"
#include "src/ic/handler-compiler.h"
#include "src/ic/ic-inl.h"
#include "src/ic/ic-compiler.h"
#include "src/ic/stub-cache.h"
#include "src/messages.h"
#include "src/prototype.h"
#include "src/runtime/runtime.h"
namespace v8 {
namespace internal {
char IC::TransitionMarkFromState(IC::State state) {
switch (state) {
case UNINITIALIZED:
return '0';
case PREMONOMORPHIC:
return '.';
case MONOMORPHIC:
return '1';
case PROTOTYPE_FAILURE:
return '^';
case POLYMORPHIC:
return 'P';
case MEGAMORPHIC:
return 'N';
case GENERIC:
return 'G';
// We never see the debugger states here, because the state is
// computed from the original code - not the patched code. Let
// these cases fall through to the unreachable code below.
case DEBUG_STUB:
break;
// Type-vector-based ICs resolve state to one of the above.
case DEFAULT:
break;
}
UNREACHABLE();
return 0;
}
const char* GetTransitionMarkModifier(KeyedAccessStoreMode mode) {
if (mode == STORE_NO_TRANSITION_HANDLE_COW) return ".COW";
if (mode == STORE_NO_TRANSITION_IGNORE_OUT_OF_BOUNDS) {
return ".IGNORE_OOB";
}
if (IsGrowStoreMode(mode)) return ".GROW";
return "";
}
#ifdef DEBUG
#define TRACE_GENERIC_IC(isolate, type, reason) \
do { \
if (FLAG_trace_ic) { \
PrintF("[%s patching generic stub in ", type); \
JavaScriptFrame::PrintTop(isolate, stdout, false, true); \
PrintF(" (%s)]\n", reason); \
} \
} while (false)
#else
#define TRACE_GENERIC_IC(isolate, type, reason) \
do { \
if (FLAG_trace_ic) { \
PrintF("[%s patching generic stub in ", type); \
PrintF("(see below) (%s)]\n", reason); \
} \
} while (false)
#endif // DEBUG
void IC::TraceIC(const char* type, Handle<Object> name) {
if (FLAG_trace_ic) {
State new_state =
UseVector() ? nexus()->StateFromFeedback() : raw_target()->ic_state();
TraceIC(type, name, state(), new_state);
}
}
void IC::TraceIC(const char* type, Handle<Object> name, State old_state,
State new_state) {
if (FLAG_trace_ic) {
Code* new_target = raw_target();
PrintF("[%s%s in ", new_target->is_keyed_stub() ? "Keyed" : "", type);
// TODO(jkummerow): Add support for "apply". The logic is roughly:
// marker = [fp_ + kMarkerOffset];
// if marker is smi and marker.value == INTERNAL and
// the frame's code == builtin(Builtins::kFunctionApply):
// then print "apply from" and advance one frame
Object* maybe_function =
Memory::Object_at(fp_ + JavaScriptFrameConstants::kFunctionOffset);
if (maybe_function->IsJSFunction()) {
JSFunction* function = JSFunction::cast(maybe_function);
JavaScriptFrame::PrintFunctionAndOffset(function, function->code(), pc(),
stdout, true);
}
ExtraICState extra_state = new_target->extra_ic_state();
const char* modifier = "";
if (new_target->kind() == Code::KEYED_STORE_IC) {
modifier = GetTransitionMarkModifier(
KeyedStoreIC::GetKeyedAccessStoreMode(extra_state));
}
PrintF(" (%c->%c%s) ", TransitionMarkFromState(old_state),
TransitionMarkFromState(new_state), modifier);
#ifdef OBJECT_PRINT
OFStream os(stdout);
name->Print(os);
#else
name->ShortPrint(stdout);
#endif
PrintF("]\n");
}
}
#define TRACE_IC(type, name) TraceIC(type, name)
IC::IC(FrameDepth depth, Isolate* isolate, FeedbackNexus* nexus,
bool for_queries_only)
: isolate_(isolate),
target_set_(false),
vector_set_(false),
target_maps_set_(false),
nexus_(nexus) {
// To improve the performance of the (much used) IC code, we unfold a few
// levels of the stack frame iteration code. This yields a ~35% speedup when
// running DeltaBlue and a ~25% speedup of gbemu with the '--nouse-ic' flag.
const Address entry = Isolate::c_entry_fp(isolate->thread_local_top());
Address constant_pool = NULL;
if (FLAG_enable_ool_constant_pool) {
constant_pool =
Memory::Address_at(entry + ExitFrameConstants::kConstantPoolOffset);
}
Address* pc_address =
reinterpret_cast<Address*>(entry + ExitFrameConstants::kCallerPCOffset);
Address fp = Memory::Address_at(entry + ExitFrameConstants::kCallerFPOffset);
// If there's another JavaScript frame on the stack or a
// StubFailureTrampoline, we need to look one frame further down the stack to
// find the frame pointer and the return address stack slot.
if (depth == EXTRA_CALL_FRAME) {
if (FLAG_enable_ool_constant_pool) {
constant_pool =
Memory::Address_at(fp + StandardFrameConstants::kConstantPoolOffset);
}
const int kCallerPCOffset = StandardFrameConstants::kCallerPCOffset;
pc_address = reinterpret_cast<Address*>(fp + kCallerPCOffset);
fp = Memory::Address_at(fp + StandardFrameConstants::kCallerFPOffset);
}
#ifdef DEBUG
StackFrameIterator it(isolate);
for (int i = 0; i < depth + 1; i++) it.Advance();
StackFrame* frame = it.frame();
DCHECK(fp == frame->fp() && pc_address == frame->pc_address());
#endif
fp_ = fp;
if (FLAG_enable_ool_constant_pool) {
raw_constant_pool_ = handle(
ConstantPoolArray::cast(reinterpret_cast<Object*>(constant_pool)),
isolate);
}
pc_address_ = StackFrame::ResolveReturnAddressLocation(pc_address);
target_ = handle(raw_target(), isolate);
kind_ = target_->kind();
state_ = (!for_queries_only && UseVector()) ? nexus->StateFromFeedback()
: target_->ic_state();
old_state_ = state_;
extra_ic_state_ = target_->extra_ic_state();
}
SharedFunctionInfo* IC::GetSharedFunctionInfo() const {
// Compute the JavaScript frame for the frame pointer of this IC
// structure. We need this to be able to find the function
// corresponding to the frame.
StackFrameIterator it(isolate());
while (it.frame()->fp() != this->fp()) it.Advance();
JavaScriptFrame* frame = JavaScriptFrame::cast(it.frame());
// Find the function on the stack and both the active code for the
// function and the original code.
JSFunction* function = frame->function();
return function->shared();
}
Code* IC::GetCode() const {
HandleScope scope(isolate());
Handle<SharedFunctionInfo> shared(GetSharedFunctionInfo(), isolate());
Code* code = shared->code();
return code;
}
Code* IC::GetOriginalCode() const {
HandleScope scope(isolate());
Handle<SharedFunctionInfo> shared(GetSharedFunctionInfo(), isolate());
DCHECK(Debug::HasDebugInfo(shared));
Code* original_code = Debug::GetDebugInfo(shared)->original_code();
DCHECK(original_code->IsCode());
return original_code;
}
bool IC::AddressIsOptimizedCode() const {
Code* host =
isolate()->inner_pointer_to_code_cache()->GetCacheEntry(address())->code;
return host->kind() == Code::OPTIMIZED_FUNCTION;
}
bool IC::AddressIsDeoptimizedCode() const {
Code* host =
isolate()->inner_pointer_to_code_cache()->GetCacheEntry(address())->code;
return host->kind() == Code::OPTIMIZED_FUNCTION &&
host->marked_for_deoptimization();
}
static void LookupForRead(LookupIterator* it) {
for (; it->IsFound(); it->Next()) {
switch (it->state()) {
case LookupIterator::NOT_FOUND:
case LookupIterator::TRANSITION:
UNREACHABLE();
case LookupIterator::JSPROXY:
return;
case LookupIterator::INTERCEPTOR: {
// If there is a getter, return; otherwise loop to perform the lookup.
Handle<JSObject> holder = it->GetHolder<JSObject>();
if (!holder->GetNamedInterceptor()->getter()->IsUndefined()) {
return;
}
break;
}
case LookupIterator::ACCESS_CHECK:
// PropertyHandlerCompiler::CheckPrototypes() knows how to emit
// access checks for global proxies.
if (it->GetHolder<JSObject>()->IsJSGlobalProxy() && it->HasAccess()) {
break;
}
return;
case LookupIterator::ACCESSOR:
case LookupIterator::INTEGER_INDEXED_EXOTIC:
case LookupIterator::DATA:
return;
}
}
}
bool IC::TryRemoveInvalidPrototypeDependentStub(Handle<Object> receiver,
Handle<String> name) {
if (!IsNameCompatibleWithPrototypeFailure(name)) return false;
if (UseVector()) {
maybe_handler_ = nexus()->FindHandlerForMap(receiver_map());
} else {
maybe_handler_ = target()->FindHandlerForMap(*receiver_map());
}
// The current map wasn't handled yet. There's no reason to stay monomorphic,
// *unless* we're moving from a deprecated map to its replacement, or
// to a more general elements kind.
// TODO(verwaest): Check if the current map is actually what the old map
// would transition to.
if (maybe_handler_.is_null()) {
if (!receiver_map()->IsJSObjectMap()) return false;
Map* first_map = FirstTargetMap();
if (first_map == NULL) return false;
Handle<Map> old_map(first_map);
if (old_map->is_deprecated()) return true;
if (IsMoreGeneralElementsKindTransition(old_map->elements_kind(),
receiver_map()->elements_kind())) {
return true;
}
return false;
}
CacheHolderFlag flag;
Handle<Map> ic_holder_map(GetICCacheHolder(receiver_map(), isolate(), &flag));
DCHECK(flag != kCacheOnReceiver || receiver->IsJSObject());
DCHECK(flag != kCacheOnPrototype || !receiver->IsJSReceiver());
DCHECK(flag != kCacheOnPrototypeReceiverIsDictionary);
if (state() == MONOMORPHIC) {
int index = ic_holder_map->IndexInCodeCache(*name, *target());
if (index >= 0) {
ic_holder_map->RemoveFromCodeCache(*name, *target(), index);
}
}
if (receiver->IsGlobalObject()) {
Handle<GlobalObject> global = Handle<GlobalObject>::cast(receiver);
LookupIterator it(global, name, LookupIterator::OWN_SKIP_INTERCEPTOR);
if (it.state() == LookupIterator::ACCESS_CHECK) return false;
if (!it.IsFound()) return false;
return it.property_details().cell_type() == PropertyCellType::kConstant;
}
return true;
}
bool IC::IsNameCompatibleWithPrototypeFailure(Handle<Object> name) {
if (target()->is_keyed_stub()) {
// Determine whether the failure is due to a name failure.
if (!name->IsName()) return false;
Name* stub_name =
UseVector() ? nexus()->FindFirstName() : target()->FindFirstName();
if (*name != stub_name) return false;
}
return true;
}
void IC::UpdateState(Handle<Object> receiver, Handle<Object> name) {
update_receiver_map(receiver);
if (!name->IsString()) return;
if (state() != MONOMORPHIC && state() != POLYMORPHIC) return;
if (receiver->IsUndefined() || receiver->IsNull()) return;
// Remove the target from the code cache if it became invalid
// because of changes in the prototype chain to avoid hitting it
// again.
if (TryRemoveInvalidPrototypeDependentStub(receiver,
Handle<String>::cast(name))) {
MarkPrototypeFailure(name);
return;
}
// The builtins object is special. It only changes when JavaScript
// builtins are loaded lazily. It is important to keep inline
// caches for the builtins object monomorphic. Therefore, if we get
// an inline cache miss for the builtins object after lazily loading
// JavaScript builtins, we return uninitialized as the state to
// force the inline cache back to monomorphic state.
if (receiver->IsJSBuiltinsObject()) state_ = PREMONOMORPHIC;
}
MaybeHandle<Object> IC::TypeError(const char* type, Handle<Object> object,
Handle<Object> key) {
HandleScope scope(isolate());
Handle<Object> args[2] = {key, object};
THROW_NEW_ERROR(isolate(), NewTypeError(type, HandleVector(args, 2)), Object);
}
MaybeHandle<Object> IC::ReferenceError(Handle<Name> name) {
HandleScope scope(isolate());
THROW_NEW_ERROR(
isolate(), NewReferenceError(MessageTemplate::kNotDefined, name), Object);
}
static void ComputeTypeInfoCountDelta(IC::State old_state, IC::State new_state,
int* polymorphic_delta,
int* generic_delta) {
switch (old_state) {
case UNINITIALIZED:
case PREMONOMORPHIC:
if (new_state == UNINITIALIZED || new_state == PREMONOMORPHIC) break;
if (new_state == MONOMORPHIC || new_state == POLYMORPHIC) {
*polymorphic_delta = 1;
} else if (new_state == MEGAMORPHIC || new_state == GENERIC) {
*generic_delta = 1;
}
break;
case MONOMORPHIC:
case POLYMORPHIC:
if (new_state == MONOMORPHIC || new_state == POLYMORPHIC) break;
*polymorphic_delta = -1;
if (new_state == MEGAMORPHIC || new_state == GENERIC) {
*generic_delta = 1;
}
break;
case MEGAMORPHIC:
case GENERIC:
if (new_state == MEGAMORPHIC || new_state == GENERIC) break;
*generic_delta = -1;
if (new_state == MONOMORPHIC || new_state == POLYMORPHIC) {
*polymorphic_delta = 1;
}
break;
case PROTOTYPE_FAILURE:
case DEBUG_STUB:
case DEFAULT:
UNREACHABLE();
}
}
void IC::OnTypeFeedbackChanged(Isolate* isolate, Address address,
State old_state, State new_state,
bool target_remains_ic_stub) {
Code* host =
isolate->inner_pointer_to_code_cache()->GetCacheEntry(address)->code;
if (host->kind() != Code::FUNCTION) return;
if (FLAG_type_info_threshold > 0 && target_remains_ic_stub &&
// Not all Code objects have TypeFeedbackInfo.
host->type_feedback_info()->IsTypeFeedbackInfo()) {
int polymorphic_delta = 0; // "Polymorphic" here includes monomorphic.
int generic_delta = 0; // "Generic" here includes megamorphic.
ComputeTypeInfoCountDelta(old_state, new_state, &polymorphic_delta,
&generic_delta);
TypeFeedbackInfo* info = TypeFeedbackInfo::cast(host->type_feedback_info());
info->change_ic_with_type_info_count(polymorphic_delta);
info->change_ic_generic_count(generic_delta);
}
if (host->type_feedback_info()->IsTypeFeedbackInfo()) {
TypeFeedbackInfo* info = TypeFeedbackInfo::cast(host->type_feedback_info());
info->change_own_type_change_checksum();
}
host->set_profiler_ticks(0);
isolate->runtime_profiler()->NotifyICChanged();
// TODO(2029): When an optimized function is patched, it would
// be nice to propagate the corresponding type information to its
// unoptimized version for the benefit of later inlining.
}
// static
void IC::OnTypeFeedbackChanged(Isolate* isolate, Code* host,
TypeFeedbackVector* vector, State old_state,
State new_state) {
if (host->kind() != Code::FUNCTION) return;
if (FLAG_type_info_threshold > 0) {
int polymorphic_delta = 0; // "Polymorphic" here includes monomorphic.
int generic_delta = 0; // "Generic" here includes megamorphic.
ComputeTypeInfoCountDelta(old_state, new_state, &polymorphic_delta,
&generic_delta);
vector->change_ic_with_type_info_count(polymorphic_delta);
vector->change_ic_generic_count(generic_delta);
}
TypeFeedbackInfo* info = TypeFeedbackInfo::cast(host->type_feedback_info());
info->change_own_type_change_checksum();
host->set_profiler_ticks(0);
isolate->runtime_profiler()->NotifyICChanged();
// TODO(2029): When an optimized function is patched, it would
// be nice to propagate the corresponding type information to its
// unoptimized version for the benefit of later inlining.
}
void IC::PostPatching(Address address, Code* target, Code* old_target) {
// Type vector based ICs update these statistics at a different time because
// they don't always patch on state change.
if (ICUseVector(target->kind())) return;
Isolate* isolate = target->GetHeap()->isolate();
State old_state = UNINITIALIZED;
State new_state = UNINITIALIZED;
bool target_remains_ic_stub = false;
if (old_target->is_inline_cache_stub() && target->is_inline_cache_stub()) {
old_state = old_target->ic_state();
new_state = target->ic_state();
target_remains_ic_stub = true;
}
OnTypeFeedbackChanged(isolate, address, old_state, new_state,
target_remains_ic_stub);
}
void IC::Clear(Isolate* isolate, Address address,
ConstantPoolArray* constant_pool) {
Code* target = GetTargetAtAddress(address, constant_pool);
// Don't clear debug break inline cache as it will remove the break point.
if (target->is_debug_stub()) return;
switch (target->kind()) {
case Code::LOAD_IC:
if (FLAG_vector_ics) return;
return LoadIC::Clear(isolate, address, target, constant_pool);
case Code::KEYED_LOAD_IC:
if (FLAG_vector_ics) return;
return KeyedLoadIC::Clear(isolate, address, target, constant_pool);
case Code::STORE_IC:
return StoreIC::Clear(isolate, address, target, constant_pool);
case Code::KEYED_STORE_IC:
return KeyedStoreIC::Clear(isolate, address, target, constant_pool);
case Code::COMPARE_IC:
return CompareIC::Clear(isolate, address, target, constant_pool);
case Code::COMPARE_NIL_IC:
return CompareNilIC::Clear(address, target, constant_pool);
case Code::CALL_IC: // CallICs are vector-based and cleared differently.
case Code::BINARY_OP_IC:
case Code::TO_BOOLEAN_IC:
// Clearing these is tricky and does not
// make any performance difference.
return;
default:
UNREACHABLE();
}
}
void KeyedLoadIC::Clear(Isolate* isolate, Address address, Code* target,
ConstantPoolArray* constant_pool) {
DCHECK(!FLAG_vector_ics);
if (IsCleared(target)) return;
// Make sure to also clear the map used in inline fast cases. If we
// do not clear these maps, cached code can keep objects alive
// through the embedded maps.
SetTargetAtAddress(address, *pre_monomorphic_stub(isolate), constant_pool);
}
void KeyedLoadIC::Clear(Isolate* isolate, Code* host, KeyedLoadICNexus* nexus) {
if (IsCleared(nexus)) return;
// Make sure to also clear the map used in inline fast cases. If we
// do not clear these maps, cached code can keep objects alive
// through the embedded maps.
State state = nexus->StateFromFeedback();
nexus->ConfigurePremonomorphic();
OnTypeFeedbackChanged(isolate, host, nexus->vector(), state, PREMONOMORPHIC);
}
void CallIC::Clear(Isolate* isolate, Code* host, CallICNexus* nexus) {
// Determine our state.
Object* feedback = nexus->vector()->Get(nexus->slot());
State state = nexus->StateFromFeedback();
if (state != UNINITIALIZED && !feedback->IsAllocationSite()) {
nexus->ConfigureUninitialized();
// The change in state must be processed.
OnTypeFeedbackChanged(isolate, host, nexus->vector(), state, UNINITIALIZED);
}
}
void LoadIC::Clear(Isolate* isolate, Address address, Code* target,
ConstantPoolArray* constant_pool) {
DCHECK(!FLAG_vector_ics);
if (IsCleared(target)) return;
Code* code = PropertyICCompiler::FindPreMonomorphic(isolate, Code::LOAD_IC,
target->extra_ic_state());
SetTargetAtAddress(address, code, constant_pool);
}
void LoadIC::Clear(Isolate* isolate, Code* host, LoadICNexus* nexus) {
if (IsCleared(nexus)) return;
State state = nexus->StateFromFeedback();
nexus->ConfigurePremonomorphic();
OnTypeFeedbackChanged(isolate, host, nexus->vector(), state, PREMONOMORPHIC);
}
void StoreIC::Clear(Isolate* isolate, Address address, Code* target,
ConstantPoolArray* constant_pool) {
if (IsCleared(target)) return;
Code* code = PropertyICCompiler::FindPreMonomorphic(isolate, Code::STORE_IC,
target->extra_ic_state());
SetTargetAtAddress(address, code, constant_pool);
}
void KeyedStoreIC::Clear(Isolate* isolate, Address address, Code* target,
ConstantPoolArray* constant_pool) {
if (IsCleared(target)) return;
SetTargetAtAddress(
address, *pre_monomorphic_stub(
isolate, StoreIC::GetLanguageMode(target->extra_ic_state())),
constant_pool);
}
void CompareIC::Clear(Isolate* isolate, Address address, Code* target,
ConstantPoolArray* constant_pool) {
DCHECK(CodeStub::GetMajorKey(target) == CodeStub::CompareIC);
CompareICStub stub(target->stub_key(), isolate);
// Only clear CompareICs that can retain objects.
if (stub.state() != CompareICState::KNOWN_OBJECT) return;
SetTargetAtAddress(address, GetRawUninitialized(isolate, stub.op()),
constant_pool);
PatchInlinedSmiCode(address, DISABLE_INLINED_SMI_CHECK);
}
// static
Handle<Code> KeyedLoadIC::ChooseMegamorphicStub(Isolate* isolate) {
if (FLAG_compiled_keyed_generic_loads) {
return KeyedLoadGenericStub(isolate).GetCode();
} else {
return isolate->builtins()->KeyedLoadIC_Megamorphic();
}
}
static bool MigrateDeprecated(Handle<Object> object) {
if (!object->IsJSObject()) return false;
Handle<JSObject> receiver = Handle<JSObject>::cast(object);
if (!receiver->map()->is_deprecated()) return false;
JSObject::MigrateInstance(Handle<JSObject>::cast(object));
return true;
}
void IC::ConfigureVectorState(IC::State new_state) {
DCHECK(UseVector());
if (kind() == Code::LOAD_IC) {
LoadICNexus* nexus = casted_nexus<LoadICNexus>();
if (new_state == PREMONOMORPHIC) {
nexus->ConfigurePremonomorphic();
} else if (new_state == MEGAMORPHIC) {
nexus->ConfigureMegamorphic();
} else {
UNREACHABLE();
}
} else if (kind() == Code::KEYED_LOAD_IC) {
KeyedLoadICNexus* nexus = casted_nexus<KeyedLoadICNexus>();
if (new_state == PREMONOMORPHIC) {
nexus->ConfigurePremonomorphic();
} else if (new_state == MEGAMORPHIC) {
nexus->ConfigureMegamorphic();
} else {
UNREACHABLE();
}
} else {
UNREACHABLE();
}
vector_set_ = true;
OnTypeFeedbackChanged(isolate(), get_host(), *vector(), saved_state(),
new_state);
}
void IC::ConfigureVectorState(Handle<Name> name, Handle<Map> map,
Handle<Code> handler) {
DCHECK(UseVector());
if (kind() == Code::LOAD_IC) {
LoadICNexus* nexus = casted_nexus<LoadICNexus>();
nexus->ConfigureMonomorphic(map, handler);
} else {
DCHECK(kind() == Code::KEYED_LOAD_IC);
KeyedLoadICNexus* nexus = casted_nexus<KeyedLoadICNexus>();
nexus->ConfigureMonomorphic(name, map, handler);
}
vector_set_ = true;
OnTypeFeedbackChanged(isolate(), get_host(), *vector(), saved_state(),
MONOMORPHIC);
}
void IC::ConfigureVectorState(Handle<Name> name, MapHandleList* maps,
CodeHandleList* handlers) {
DCHECK(UseVector());
if (kind() == Code::LOAD_IC) {
LoadICNexus* nexus = casted_nexus<LoadICNexus>();
nexus->ConfigurePolymorphic(maps, handlers);
} else {
DCHECK(kind() == Code::KEYED_LOAD_IC);
KeyedLoadICNexus* nexus = casted_nexus<KeyedLoadICNexus>();
nexus->ConfigurePolymorphic(name, maps, handlers);
}
vector_set_ = true;
OnTypeFeedbackChanged(isolate(), get_host(), *vector(), saved_state(),
POLYMORPHIC);
}
MaybeHandle<Object> LoadIC::Load(Handle<Object> object, Handle<Name> name) {
// If the object is undefined or null it's illegal to try to get any
// of its properties; throw a TypeError in that case.
if (object->IsUndefined() || object->IsNull()) {
return TypeError("non_object_property_load", object, name);
}
// Check if the name is trivially convertible to an index and get
// the element or char if so.
uint32_t index;
if (kind() == Code::KEYED_LOAD_IC && name->AsArrayIndex(&index)) {
// Rewrite to the generic keyed load stub.
if (FLAG_use_ic) {
if (UseVector()) {
ConfigureVectorState(MEGAMORPHIC);
} else {
set_target(*megamorphic_stub());
}
TRACE_IC("LoadIC", name);
TRACE_GENERIC_IC(isolate(), "LoadIC", "name as array index");
}
Handle<Object> result;
ASSIGN_RETURN_ON_EXCEPTION(
isolate(), result,
Runtime::GetElementOrCharAt(isolate(), object, index), Object);
return result;
}
bool use_ic = MigrateDeprecated(object) ? false : FLAG_use_ic;
if (object->IsGlobalObject() && name->IsString()) {
// Look up in script context table.
Handle<String> str_name = Handle<String>::cast(name);
Handle<GlobalObject> global = Handle<GlobalObject>::cast(object);
Handle<ScriptContextTable> script_contexts(
global->native_context()->script_context_table());
ScriptContextTable::LookupResult lookup_result;
if (ScriptContextTable::Lookup(script_contexts, str_name, &lookup_result)) {
Handle<Object> result =
FixedArray::get(ScriptContextTable::GetContext(
script_contexts, lookup_result.context_index),
lookup_result.slot_index);
if (*result == *isolate()->factory()->the_hole_value()) {
// Do not install stubs and stay pre-monomorphic for
// uninitialized accesses.
return ReferenceError(name);
}
if (use_ic && LoadScriptContextFieldStub::Accepted(&lookup_result)) {
LoadScriptContextFieldStub stub(isolate(), &lookup_result);
PatchCache(name, stub.GetCode());
}
return result;
}
}
// Named lookup in the object.
LookupIterator it(object, name);
LookupForRead(&it);
if (it.IsFound() || !IsUndeclaredGlobal(object)) {
// Update inline cache and stub cache.
if (use_ic) UpdateCaches(&it);
// Get the property.
Handle<Object> result;
ASSIGN_RETURN_ON_EXCEPTION(isolate(), result, Object::GetProperty(&it),
Object);
if (it.IsFound()) {
return result;
} else if (!IsUndeclaredGlobal(object)) {
LOG(isolate(), SuspectReadEvent(*name, *object));
return result;
}
}
return ReferenceError(name);
}
static bool AddOneReceiverMapIfMissing(MapHandleList* receiver_maps,
Handle<Map> new_receiver_map) {
DCHECK(!new_receiver_map.is_null());
for (int current = 0; current < receiver_maps->length(); ++current) {
if (!receiver_maps->at(current).is_null() &&
receiver_maps->at(current).is_identical_to(new_receiver_map)) {
return false;
}
}
receiver_maps->Add(new_receiver_map);
return true;
}
bool IC::UpdatePolymorphicIC(Handle<Name> name, Handle<Code> code) {
if (!code->is_handler()) return false;
if (target()->is_keyed_stub() && state() != PROTOTYPE_FAILURE) return false;
Handle<Map> map = receiver_map();
MapHandleList maps;
CodeHandleList handlers;
TargetMaps(&maps);
int number_of_maps = maps.length();
int deprecated_maps = 0;
int handler_to_overwrite = -1;
for (int i = 0; i < number_of_maps; i++) {
Handle<Map> current_map = maps.at(i);
if (current_map->is_deprecated()) {
// Filter out deprecated maps to ensure their instances get migrated.
++deprecated_maps;
} else if (map.is_identical_to(current_map)) {
// If the receiver type is already in the polymorphic IC, this indicates
// there was a prototoype chain failure. In that case, just overwrite the
// handler.
handler_to_overwrite = i;
} else if (handler_to_overwrite == -1 &&
IsTransitionOfMonomorphicTarget(*current_map, *map)) {
handler_to_overwrite = i;
}
}
int number_of_valid_maps =
number_of_maps - deprecated_maps - (handler_to_overwrite != -1);
if (number_of_valid_maps >= 4) return false;
if (number_of_maps == 0 && state() != MONOMORPHIC && state() != POLYMORPHIC) {
return false;
}
if (UseVector()) {
if (!nexus()->FindHandlers(&handlers, maps.length())) return false;
} else {
if (!target()->FindHandlers(&handlers, maps.length())) return false;
}
number_of_valid_maps++;
if (number_of_valid_maps > 1 && target()->is_keyed_stub()) return false;
Handle<Code> ic;
if (number_of_valid_maps == 1) {
if (UseVector()) {
ConfigureVectorState(name, receiver_map(), code);
} else {
ic = PropertyICCompiler::ComputeMonomorphic(kind(), name, map, code,
extra_ic_state());
}
} else {
if (handler_to_overwrite >= 0) {
handlers.Set(handler_to_overwrite, code);
if (!map.is_identical_to(maps.at(handler_to_overwrite))) {
maps.Set(handler_to_overwrite, map);
}
} else {
maps.Add(map);
handlers.Add(code);
}
if (UseVector()) {
ConfigureVectorState(name, &maps, &handlers);
} else {
ic = PropertyICCompiler::ComputePolymorphic(kind(), &maps, &handlers,
number_of_valid_maps, name,
extra_ic_state());
}
}
if (!UseVector()) set_target(*ic);
return true;
}
void IC::UpdateMonomorphicIC(Handle<Code> handler, Handle<Name> name) {
DCHECK(handler->is_handler());
if (UseVector()) {
ConfigureVectorState(name, receiver_map(), handler);
} else {
Handle<Code> ic = PropertyICCompiler::ComputeMonomorphic(
kind(), name, receiver_map(), handler, extra_ic_state());
set_target(*ic);
}
}
void IC::CopyICToMegamorphicCache(Handle<Name> name) {
MapHandleList maps;
CodeHandleList handlers;
TargetMaps(&maps);
if (!target()->FindHandlers(&handlers, maps.length())) return;
for (int i = 0; i < maps.length(); i++) {
UpdateMegamorphicCache(*maps.at(i), *name, *handlers.at(i));
}
}
bool IC::IsTransitionOfMonomorphicTarget(Map* source_map, Map* target_map) {
if (source_map == NULL) return true;
if (target_map == NULL) return false;
ElementsKind target_elements_kind = target_map->elements_kind();
bool more_general_transition = IsMoreGeneralElementsKindTransition(
source_map->elements_kind(), target_elements_kind);
Map* transitioned_map =
more_general_transition
? source_map->LookupElementsTransitionMap(target_elements_kind)
: NULL;
return transitioned_map == target_map;
}
void IC::PatchCache(Handle<Name> name, Handle<Code> code) {
switch (state()) {
case UNINITIALIZED:
case PREMONOMORPHIC:
UpdateMonomorphicIC(code, name);
break;
case PROTOTYPE_FAILURE:
case MONOMORPHIC:
case POLYMORPHIC:
if (!target()->is_keyed_stub() || state() == PROTOTYPE_FAILURE) {
if (UpdatePolymorphicIC(name, code)) break;
// For keyed stubs, we can't know whether old handlers were for the
// same key.
CopyICToMegamorphicCache(name);
}
if (UseVector()) {
ConfigureVectorState(MEGAMORPHIC);
} else {
set_target(*megamorphic_stub());
}
// Fall through.
case MEGAMORPHIC:
UpdateMegamorphicCache(*receiver_map(), *name, *code);
// Indicate that we've handled this case.
if (UseVector()) {
vector_set_ = true;
} else {
target_set_ = true;
}
break;
case DEBUG_STUB:
break;
case DEFAULT:
case GENERIC:
UNREACHABLE();
break;
}
}
Handle<Code> LoadIC::initialize_stub(Isolate* isolate,
ExtraICState extra_state) {
if (FLAG_vector_ics) {
return LoadICTrampolineStub(isolate, LoadICState(extra_state)).GetCode();
}
return PropertyICCompiler::ComputeLoad(isolate, UNINITIALIZED, extra_state);
}
Handle<Code> LoadIC::load_global(Isolate* isolate, Handle<GlobalObject> global,
Handle<String> name) {
// This special IC doesn't work with vector ics.
DCHECK(!FLAG_vector_ics);
Handle<ScriptContextTable> script_contexts(
global->native_context()->script_context_table());
ScriptContextTable::LookupResult lookup_result;
if (ScriptContextTable::Lookup(script_contexts, name, &lookup_result)) {
return initialize_stub(isolate, LoadICState(CONTEXTUAL).GetExtraICState());
}
Handle<Map> global_map(global->map());
Handle<Code> handler = PropertyHandlerCompiler::Find(
name, global_map, Code::LOAD_IC, kCacheOnReceiver, Code::NORMAL);
if (handler.is_null()) {
LookupIterator it(global, name);
if (!it.IsFound() || !it.GetHolder<JSObject>().is_identical_to(global) ||
it.state() != LookupIterator::DATA) {
return initialize_stub(isolate,
LoadICState(CONTEXTUAL).GetExtraICState());
}
NamedLoadHandlerCompiler compiler(isolate, global_map, global,
kCacheOnReceiver);
Handle<PropertyCell> cell = it.GetPropertyCell();
handler = compiler.CompileLoadGlobal(cell, name, it.IsConfigurable());
Map::UpdateCodeCache(global_map, name, handler);
}
return PropertyICCompiler::ComputeMonomorphic(
Code::LOAD_IC, name, handle(global->map()), handler,
LoadICState(CONTEXTUAL).GetExtraICState());
}
Handle<Code> LoadIC::initialize_stub_in_optimized_code(
Isolate* isolate, ExtraICState extra_state, State initialization_state) {
if (FLAG_vector_ics) {
return VectorRawLoadStub(isolate, LoadICState(extra_state)).GetCode();
}
return PropertyICCompiler::ComputeLoad(isolate, initialization_state,
extra_state);
}
Handle<Code> KeyedLoadIC::initialize_stub(Isolate* isolate) {
if (FLAG_vector_ics) {
return KeyedLoadICTrampolineStub(isolate).GetCode();