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ic.cc
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ic.cc
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// Copyright 2012 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "v8.h"
#include "accessors.h"
#include "api.h"
#include "arguments.h"
#include "codegen.h"
#include "execution.h"
#include "ic-inl.h"
#include "runtime.h"
#include "stub-cache.h"
namespace v8 {
namespace internal {
#ifdef DEBUG
char IC::TransitionMarkFromState(IC::State state) {
switch (state) {
case UNINITIALIZED: return '0';
case PREMONOMORPHIC: return 'P';
case MONOMORPHIC: return '1';
case MONOMORPHIC_PROTOTYPE_FAILURE: return '^';
case MEGAMORPHIC: return IsGeneric() ? 'G' : 'N';
// 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_BREAK: break;
case DEBUG_PREPARE_STEP_IN: break;
}
UNREACHABLE();
return 0;
}
void IC::TraceIC(const char* type,
Handle<Object> name,
State old_state,
Code* new_target) {
if (FLAG_trace_ic) {
State new_state = StateFrom(new_target,
HEAP->undefined_value(),
HEAP->undefined_value());
PrintF("[%s in ", type);
StackFrameIterator it;
while (it.frame()->fp() != this->fp()) it.Advance();
StackFrame* raw_frame = it.frame();
if (raw_frame->is_internal()) {
Isolate* isolate = new_target->GetIsolate();
Code* apply_builtin = isolate->builtins()->builtin(
Builtins::kFunctionApply);
if (raw_frame->unchecked_code() == apply_builtin) {
PrintF("apply from ");
it.Advance();
raw_frame = it.frame();
}
}
JavaScriptFrame::PrintTop(stdout, false, true);
bool new_can_grow =
Code::GetKeyedAccessGrowMode(new_target->extra_ic_state()) ==
ALLOW_JSARRAY_GROWTH;
PrintF(" (%c->%c%s)",
TransitionMarkFromState(old_state),
TransitionMarkFromState(new_state),
new_can_grow ? ".GROW" : "");
name->Print();
PrintF("]\n");
}
}
#define TRACE_GENERIC_IC(type, reason) \
do { \
if (FLAG_trace_ic) { \
PrintF("[%s patching generic stub in ", type); \
JavaScriptFrame::PrintTop(stdout, false, true); \
PrintF(" (%s)]\n", reason); \
} \
} while (false)
#else
#define TRACE_GENERIC_IC(type, reason)
#endif // DEBUG
#define TRACE_IC(type, name, old_state, new_target) \
ASSERT((TraceIC(type, name, old_state, new_target), true))
IC::IC(FrameDepth depth, Isolate* isolate) : isolate_(isolate) {
ASSERT(isolate == Isolate::Current());
// 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 with the '--nouse-ic' flag.
const Address entry =
Isolate::c_entry_fp(isolate->thread_local_top());
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, 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) {
const int kCallerPCOffset = StandardFrameConstants::kCallerPCOffset;
pc_address = reinterpret_cast<Address*>(fp + kCallerPCOffset);
fp = Memory::Address_at(fp + StandardFrameConstants::kCallerFPOffset);
}
#ifdef DEBUG
StackFrameIterator it;
for (int i = 0; i < depth + 1; i++) it.Advance();
StackFrame* frame = it.frame();
ASSERT(fp == frame->fp() && pc_address == frame->pc_address());
#endif
fp_ = fp;
pc_address_ = pc_address;
}
#ifdef ENABLE_DEBUGGER_SUPPORT
Address IC::OriginalCodeAddress() const {
HandleScope scope;
// 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;
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 = JSFunction::cast(frame->function());
Handle<SharedFunctionInfo> shared(function->shared());
Code* code = shared->code();
ASSERT(Debug::HasDebugInfo(shared));
Code* original_code = Debug::GetDebugInfo(shared)->original_code();
ASSERT(original_code->IsCode());
// Get the address of the call site in the active code. This is the
// place where the call to DebugBreakXXX is and where the IC
// normally would be.
Address addr = pc() - Assembler::kCallTargetAddressOffset;
// Return the address in the original code. This is the place where
// the call which has been overwritten by the DebugBreakXXX resides
// and the place where the inline cache system should look.
intptr_t delta =
original_code->instruction_start() - code->instruction_start();
return addr + delta;
}
#endif
static bool HasNormalObjectsInPrototypeChain(Isolate* isolate,
LookupResult* lookup,
Object* receiver) {
Object* end = lookup->IsProperty()
? lookup->holder() : Object::cast(isolate->heap()->null_value());
for (Object* current = receiver;
current != end;
current = current->GetPrototype()) {
if (current->IsJSObject() &&
!JSObject::cast(current)->HasFastProperties() &&
!current->IsJSGlobalProxy() &&
!current->IsJSGlobalObject()) {
return true;
}
}
return false;
}
static bool TryRemoveInvalidPrototypeDependentStub(Code* target,
Object* receiver,
Object* name) {
InlineCacheHolderFlag cache_holder =
Code::ExtractCacheHolderFromFlags(target->flags());
if (cache_holder == OWN_MAP && !receiver->IsJSObject()) {
// The stub was generated for JSObject but called for non-JSObject.
// IC::GetCodeCacheHolder is not applicable.
return false;
} else if (cache_holder == PROTOTYPE_MAP &&
receiver->GetPrototype()->IsNull()) {
// IC::GetCodeCacheHolder is not applicable.
return false;
}
Map* map = IC::GetCodeCacheHolder(receiver, cache_holder)->map();
// Decide whether the inline cache failed because of changes to the
// receiver itself or changes to one of its prototypes.
//
// If there are changes to the receiver itself, the map of the
// receiver will have changed and the current target will not be in
// the receiver map's code cache. Therefore, if the current target
// is in the receiver map's code cache, the inline cache failed due
// to prototype check failure.
int index = map->IndexInCodeCache(name, target);
if (index >= 0) {
map->RemoveFromCodeCache(String::cast(name), target, index);
return true;
}
return false;
}
IC::State IC::StateFrom(Code* target, Object* receiver, Object* name) {
IC::State state = target->ic_state();
if (state != MONOMORPHIC || !name->IsString()) return state;
if (receiver->IsUndefined() || receiver->IsNull()) return state;
// For keyed load/store/call, the most likely cause of cache failure is
// that the key has changed. We do not distinguish between
// prototype and non-prototype failures for keyed access.
Code::Kind kind = target->kind();
if (kind == Code::KEYED_LOAD_IC ||
kind == Code::KEYED_STORE_IC ||
kind == Code::KEYED_CALL_IC) {
return MONOMORPHIC;
}
// Remove the target from the code cache if it became invalid
// because of changes in the prototype chain to avoid hitting it
// again.
// Call stubs handle this later to allow extra IC state
// transitions.
if (kind != Code::CALL_IC &&
TryRemoveInvalidPrototypeDependentStub(target, receiver, name)) {
return MONOMORPHIC_PROTOTYPE_FAILURE;
}
// 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()) {
return UNINITIALIZED;
}
return MONOMORPHIC;
}
RelocInfo::Mode IC::ComputeMode() {
Address addr = address();
Code* code = Code::cast(isolate()->heap()->FindCodeObject(addr));
for (RelocIterator it(code, RelocInfo::kCodeTargetMask);
!it.done(); it.next()) {
RelocInfo* info = it.rinfo();
if (info->pc() == addr) return info->rmode();
}
UNREACHABLE();
return RelocInfo::NONE;
}
Failure* IC::TypeError(const char* type,
Handle<Object> object,
Handle<Object> key) {
HandleScope scope(isolate());
Handle<Object> args[2] = { key, object };
Handle<Object> error = isolate()->factory()->NewTypeError(
type, HandleVector(args, 2));
return isolate()->Throw(*error);
}
Failure* IC::ReferenceError(const char* type, Handle<String> name) {
HandleScope scope(isolate());
Handle<Object> error = isolate()->factory()->NewReferenceError(
type, HandleVector(&name, 1));
return isolate()->Throw(*error);
}
static int ComputeTypeInfoCountDelta(IC::State old_state, IC::State new_state) {
bool was_uninitialized =
old_state == UNINITIALIZED || old_state == PREMONOMORPHIC;
bool is_uninitialized =
new_state == UNINITIALIZED || new_state == PREMONOMORPHIC;
return (was_uninitialized && !is_uninitialized) ? 1 :
(!was_uninitialized && is_uninitialized) ? -1 : 0;
}
void IC::PostPatching(Address address, Code* target, Code* old_target) {
if (FLAG_type_info_threshold == 0 && !FLAG_watch_ic_patching) {
return;
}
Code* host = target->GetHeap()->isolate()->
inner_pointer_to_code_cache()->GetCacheEntry(address)->code;
if (host->kind() != Code::FUNCTION) return;
if (FLAG_type_info_threshold > 0 &&
old_target->is_inline_cache_stub() &&
target->is_inline_cache_stub()) {
int delta = ComputeTypeInfoCountDelta(old_target->ic_state(),
target->ic_state());
// Not all Code objects have TypeFeedbackInfo.
if (host->type_feedback_info()->IsTypeFeedbackInfo() && delta != 0) {
TypeFeedbackInfo* info =
TypeFeedbackInfo::cast(host->type_feedback_info());
info->change_ic_with_type_info_count(delta);
}
}
if (host->type_feedback_info()->IsTypeFeedbackInfo()) {
TypeFeedbackInfo* info =
TypeFeedbackInfo::cast(host->type_feedback_info());
info->change_own_type_change_checksum();
}
if (FLAG_watch_ic_patching) {
host->set_profiler_ticks(0);
Isolate::Current()->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::Clear(Address address) {
Code* target = GetTargetAtAddress(address);
// Don't clear debug break inline cache as it will remove the break point.
if (target->ic_state() == DEBUG_BREAK) return;
switch (target->kind()) {
case Code::LOAD_IC: return LoadIC::Clear(address, target);
case Code::KEYED_LOAD_IC:
return KeyedLoadIC::Clear(address, target);
case Code::STORE_IC: return StoreIC::Clear(address, target);
case Code::KEYED_STORE_IC:
return KeyedStoreIC::Clear(address, target);
case Code::CALL_IC: return CallIC::Clear(address, target);
case Code::KEYED_CALL_IC: return KeyedCallIC::Clear(address, target);
case Code::COMPARE_IC: return CompareIC::Clear(address, target);
case Code::UNARY_OP_IC:
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 CallICBase::Clear(Address address, Code* target) {
if (target->ic_state() == UNINITIALIZED) return;
bool contextual = CallICBase::Contextual::decode(target->extra_ic_state());
Code* code =
Isolate::Current()->stub_cache()->FindCallInitialize(
target->arguments_count(),
contextual ? RelocInfo::CODE_TARGET_CONTEXT : RelocInfo::CODE_TARGET,
target->kind());
SetTargetAtAddress(address, code);
}
void KeyedLoadIC::Clear(Address address, Code* target) {
if (target->ic_state() == UNINITIALIZED) 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, initialize_stub());
}
void LoadIC::Clear(Address address, Code* target) {
if (target->ic_state() == UNINITIALIZED) return;
SetTargetAtAddress(address, initialize_stub());
}
void StoreIC::Clear(Address address, Code* target) {
if (target->ic_state() == UNINITIALIZED) return;
SetTargetAtAddress(address,
(Code::GetStrictMode(target->extra_ic_state()) == kStrictMode)
? initialize_stub_strict()
: initialize_stub());
}
void KeyedStoreIC::Clear(Address address, Code* target) {
if (target->ic_state() == UNINITIALIZED) return;
SetTargetAtAddress(address,
(Code::GetStrictMode(target->extra_ic_state()) == kStrictMode)
? initialize_stub_strict()
: initialize_stub());
}
void CompareIC::Clear(Address address, Code* target) {
// Only clear ICCompareStubs, we currently cannot clear generic CompareStubs.
if (target->major_key() != CodeStub::CompareIC) return;
// Only clear CompareICs that can retain objects.
if (target->compare_state() != KNOWN_OBJECTS) return;
Token::Value op = CompareIC::ComputeOperation(target);
SetTargetAtAddress(address, GetRawUninitialized(op));
PatchInlinedSmiCode(address, DISABLE_INLINED_SMI_CHECK);
}
static bool HasInterceptorGetter(JSObject* object) {
return !object->GetNamedInterceptor()->getter()->IsUndefined();
}
static void LookupForRead(Handle<Object> object,
Handle<String> name,
LookupResult* lookup) {
// Skip all the objects with named interceptors, but
// without actual getter.
while (true) {
object->Lookup(*name, lookup);
// Besides normal conditions (property not found or it's not
// an interceptor), bail out if lookup is not cacheable: we won't
// be able to IC it anyway and regular lookup should work fine.
if (!lookup->IsInterceptor() || !lookup->IsCacheable()) {
return;
}
Handle<JSObject> holder(lookup->holder());
if (HasInterceptorGetter(*holder)) {
return;
}
holder->LocalLookupRealNamedProperty(*name, lookup);
if (lookup->IsFound()) {
ASSERT(!lookup->IsInterceptor());
return;
}
Handle<Object> proto(holder->GetPrototype());
if (proto->IsNull()) {
ASSERT(!lookup->IsFound());
return;
}
object = proto;
}
}
Handle<Object> CallICBase::TryCallAsFunction(Handle<Object> object) {
Handle<Object> delegate = Execution::GetFunctionDelegate(object);
if (delegate->IsJSFunction() && !object->IsJSFunctionProxy()) {
// Patch the receiver and use the delegate as the function to
// invoke. This is used for invoking objects as if they were functions.
const int argc = target()->arguments_count();
StackFrameLocator locator;
JavaScriptFrame* frame = locator.FindJavaScriptFrame(0);
int index = frame->ComputeExpressionsCount() - (argc + 1);
frame->SetExpression(index, *object);
}
return delegate;
}
void CallICBase::ReceiverToObjectIfRequired(Handle<Object> callee,
Handle<Object> object) {
while (callee->IsJSFunctionProxy()) {
callee = Handle<Object>(JSFunctionProxy::cast(*callee)->call_trap());
}
if (callee->IsJSFunction()) {
Handle<JSFunction> function = Handle<JSFunction>::cast(callee);
if (!function->shared()->is_classic_mode() || function->IsBuiltin()) {
// Do not wrap receiver for strict mode functions or for builtins.
return;
}
}
// And only wrap string, number or boolean.
if (object->IsString() || object->IsNumber() || object->IsBoolean()) {
// Change the receiver to the result of calling ToObject on it.
const int argc = this->target()->arguments_count();
StackFrameLocator locator;
JavaScriptFrame* frame = locator.FindJavaScriptFrame(0);
int index = frame->ComputeExpressionsCount() - (argc + 1);
frame->SetExpression(index, *isolate()->factory()->ToObject(object));
}
}
MaybeObject* CallICBase::LoadFunction(State state,
Code::ExtraICState extra_ic_state,
Handle<Object> object,
Handle<String> 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_call", object, name);
}
// Check if the name is trivially convertible to an index and get
// the element if so.
uint32_t index;
if (name->AsArrayIndex(&index)) {
Handle<Object> result = Object::GetElement(object, index);
RETURN_IF_EMPTY_HANDLE(isolate(), result);
if (result->IsJSFunction()) return *result;
// Try to find a suitable function delegate for the object at hand.
result = TryCallAsFunction(result);
if (result->IsJSFunction()) return *result;
// Otherwise, it will fail in the lookup step.
}
// Lookup the property in the object.
LookupResult lookup(isolate());
LookupForRead(object, name, &lookup);
if (!lookup.IsFound()) {
// If the object does not have the requested property, check which
// exception we need to throw.
return IsContextual(object)
? ReferenceError("not_defined", name)
: TypeError("undefined_method", object, name);
}
// Lookup is valid: Update inline cache and stub cache.
if (FLAG_use_ic) {
UpdateCaches(&lookup, state, extra_ic_state, object, name);
}
// Get the property.
PropertyAttributes attr;
Handle<Object> result =
Object::GetProperty(object, object, &lookup, name, &attr);
RETURN_IF_EMPTY_HANDLE(isolate(), result);
if (lookup.IsInterceptor() && attr == ABSENT) {
// If the object does not have the requested property, check which
// exception we need to throw.
return IsContextual(object)
? ReferenceError("not_defined", name)
: TypeError("undefined_method", object, name);
}
ASSERT(!result->IsTheHole());
// Make receiver an object if the callee requires it. Strict mode or builtin
// functions do not wrap the receiver, non-strict functions and objects
// called as functions do.
ReceiverToObjectIfRequired(result, object);
if (result->IsJSFunction()) {
Handle<JSFunction> function = Handle<JSFunction>::cast(result);
#ifdef ENABLE_DEBUGGER_SUPPORT
// Handle stepping into a function if step into is active.
Debug* debug = isolate()->debug();
if (debug->StepInActive()) {
// Protect the result in a handle as the debugger can allocate and might
// cause GC.
debug->HandleStepIn(function, object, fp(), false);
}
#endif
return *function;
}
// Try to find a suitable function delegate for the object at hand.
result = TryCallAsFunction(result);
if (result->IsJSFunction()) return *result;
return TypeError("property_not_function", object, name);
}
bool CallICBase::TryUpdateExtraICState(LookupResult* lookup,
Handle<Object> object,
Code::ExtraICState* extra_ic_state) {
ASSERT(kind_ == Code::CALL_IC);
if (lookup->type() != CONSTANT_FUNCTION) return false;
JSFunction* function = lookup->GetConstantFunction();
if (!function->shared()->HasBuiltinFunctionId()) return false;
// Fetch the arguments passed to the called function.
const int argc = target()->arguments_count();
Address entry = isolate()->c_entry_fp(isolate()->thread_local_top());
Address fp = Memory::Address_at(entry + ExitFrameConstants::kCallerFPOffset);
Arguments args(argc + 1,
&Memory::Object_at(fp +
StandardFrameConstants::kCallerSPOffset +
argc * kPointerSize));
switch (function->shared()->builtin_function_id()) {
case kStringCharCodeAt:
case kStringCharAt:
if (object->IsString()) {
String* string = String::cast(*object);
// Check there's the right string value or wrapper in the receiver slot.
ASSERT(string == args[0] || string == JSValue::cast(args[0])->value());
// If we're in the default (fastest) state and the index is
// out of bounds, update the state to record this fact.
if (StringStubState::decode(*extra_ic_state) == DEFAULT_STRING_STUB &&
argc >= 1 && args[1]->IsNumber()) {
double index = DoubleToInteger(args.number_at(1));
if (index < 0 || index >= string->length()) {
*extra_ic_state =
StringStubState::update(*extra_ic_state,
STRING_INDEX_OUT_OF_BOUNDS);
return true;
}
}
}
break;
default:
return false;
}
return false;
}
Handle<Code> CallICBase::ComputeMonomorphicStub(LookupResult* lookup,
State state,
Code::ExtraICState extra_state,
Handle<Object> object,
Handle<String> name) {
int argc = target()->arguments_count();
Handle<JSObject> holder(lookup->holder());
switch (lookup->type()) {
case FIELD: {
int index = lookup->GetFieldIndex();
return isolate()->stub_cache()->ComputeCallField(
argc, kind_, extra_state, name, object, holder, index);
}
case CONSTANT_FUNCTION: {
// Get the constant function and compute the code stub for this
// call; used for rewriting to monomorphic state and making sure
// that the code stub is in the stub cache.
Handle<JSFunction> function(lookup->GetConstantFunction());
return isolate()->stub_cache()->ComputeCallConstant(
argc, kind_, extra_state, name, object, holder, function);
}
case NORMAL: {
// If we return a null handle, the IC will not be patched.
if (!object->IsJSObject()) return Handle<Code>::null();
Handle<JSObject> receiver = Handle<JSObject>::cast(object);
if (holder->IsGlobalObject()) {
Handle<GlobalObject> global = Handle<GlobalObject>::cast(holder);
Handle<JSGlobalPropertyCell> cell(global->GetPropertyCell(lookup));
if (!cell->value()->IsJSFunction()) return Handle<Code>::null();
Handle<JSFunction> function(JSFunction::cast(cell->value()));
return isolate()->stub_cache()->ComputeCallGlobal(
argc, kind_, extra_state, name, receiver, global, cell, function);
} else {
// There is only one shared stub for calling normalized
// properties. It does not traverse the prototype chain, so the
// property must be found in the receiver for the stub to be
// applicable.
if (!holder.is_identical_to(receiver)) return Handle<Code>::null();
return isolate()->stub_cache()->ComputeCallNormal(
argc, kind_, extra_state);
}
break;
}
case INTERCEPTOR:
ASSERT(HasInterceptorGetter(*holder));
return isolate()->stub_cache()->ComputeCallInterceptor(
argc, kind_, extra_state, name, object, holder);
default:
return Handle<Code>::null();
}
}
void CallICBase::UpdateCaches(LookupResult* lookup,
State state,
Code::ExtraICState extra_ic_state,
Handle<Object> object,
Handle<String> name) {
// Bail out if we didn't find a result.
if (!lookup->IsProperty() || !lookup->IsCacheable()) return;
if (lookup->holder() != *object &&
HasNormalObjectsInPrototypeChain(
isolate(), lookup, object->GetPrototype())) {
// Suppress optimization for prototype chains with slow properties objects
// in the middle.
return;
}
// Compute the number of arguments.
int argc = target()->arguments_count();
bool had_proto_failure = false;
Handle<Code> code;
if (state == UNINITIALIZED) {
// This is the first time we execute this inline cache.
// Set the target to the pre monomorphic stub to delay
// setting the monomorphic state.
code = isolate()->stub_cache()->ComputeCallPreMonomorphic(
argc, kind_, extra_ic_state);
} else if (state == MONOMORPHIC) {
if (kind_ == Code::CALL_IC &&
TryUpdateExtraICState(lookup, object, &extra_ic_state)) {
code = ComputeMonomorphicStub(lookup, state, extra_ic_state,
object, name);
} else if (kind_ == Code::CALL_IC &&
TryRemoveInvalidPrototypeDependentStub(target(),
*object,
*name)) {
had_proto_failure = true;
code = ComputeMonomorphicStub(lookup, state, extra_ic_state,
object, name);
} else {
code = isolate()->stub_cache()->ComputeCallMegamorphic(
argc, kind_, extra_ic_state);
}
} else {
code = ComputeMonomorphicStub(lookup, state, extra_ic_state,
object, name);
}
// If there's no appropriate stub we simply avoid updating the caches.
if (code.is_null()) return;
// Patch the call site depending on the state of the cache.
if (state == UNINITIALIZED ||
state == PREMONOMORPHIC ||
state == MONOMORPHIC ||
state == MONOMORPHIC_PROTOTYPE_FAILURE) {
set_target(*code);
} else if (state == MEGAMORPHIC) {
// Cache code holding map should be consistent with
// GenerateMonomorphicCacheProbe. It is not the map which holds the stub.
Handle<JSObject> cache_object = object->IsJSObject()
? Handle<JSObject>::cast(object)
: Handle<JSObject>(JSObject::cast(object->GetPrototype()));
// Update the stub cache.
isolate()->stub_cache()->Set(*name, cache_object->map(), *code);
}
if (had_proto_failure) state = MONOMORPHIC_PROTOTYPE_FAILURE;
TRACE_IC(kind_ == Code::CALL_IC ? "CallIC" : "KeyedCallIC",
name, state, target());
}
MaybeObject* KeyedCallIC::LoadFunction(State state,
Handle<Object> object,
Handle<Object> key) {
if (key->IsSymbol()) {
return CallICBase::LoadFunction(state,
Code::kNoExtraICState,
object,
Handle<String>::cast(key));
}
if (object->IsUndefined() || object->IsNull()) {
return TypeError("non_object_property_call", object, key);
}
if (FLAG_use_ic && state != MEGAMORPHIC && object->IsHeapObject()) {
int argc = target()->arguments_count();
Handle<Map> map =
isolate()->factory()->non_strict_arguments_elements_map();
if (object->IsJSObject() &&
Handle<JSObject>::cast(object)->elements()->map() == *map) {
Handle<Code> code = isolate()->stub_cache()->ComputeCallArguments(
argc, Code::KEYED_CALL_IC);
set_target(*code);
TRACE_IC("KeyedCallIC", key, state, target());
} else if (!object->IsAccessCheckNeeded()) {
Handle<Code> code = isolate()->stub_cache()->ComputeCallMegamorphic(
argc, Code::KEYED_CALL_IC, Code::kNoExtraICState);
set_target(*code);
TRACE_IC("KeyedCallIC", key, state, target());
}
}
Handle<Object> result = GetProperty(object, key);
RETURN_IF_EMPTY_HANDLE(isolate(), result);
// Make receiver an object if the callee requires it. Strict mode or builtin
// functions do not wrap the receiver, non-strict functions and objects
// called as functions do.
ReceiverToObjectIfRequired(result, object);
if (result->IsJSFunction()) return *result;
result = TryCallAsFunction(result);
if (result->IsJSFunction()) return *result;
return TypeError("property_not_function", object, key);
}
MaybeObject* LoadIC::Load(State state,
Handle<Object> object,
Handle<String> 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);
}
if (FLAG_use_ic) {
// Use specialized code for getting the length of strings and
// string wrapper objects. The length property of string wrapper
// objects is read-only and therefore always returns the length of
// the underlying string value. See ECMA-262 15.5.5.1.
if ((object->IsString() || object->IsStringWrapper()) &&
name->Equals(isolate()->heap()->length_symbol())) {
Handle<Code> stub;
if (state == UNINITIALIZED) {
stub = pre_monomorphic_stub();
} else if (state == PREMONOMORPHIC) {
stub = object->IsString()
? isolate()->builtins()->LoadIC_StringLength()
: isolate()->builtins()->LoadIC_StringWrapperLength();
} else if (state == MONOMORPHIC && object->IsStringWrapper()) {
stub = isolate()->builtins()->LoadIC_StringWrapperLength();
} else if (state != MEGAMORPHIC) {
stub = megamorphic_stub();
}
if (!stub.is_null()) {
set_target(*stub);
#ifdef DEBUG
if (FLAG_trace_ic) PrintF("[LoadIC : +#length /string]\n");
#endif
}
// Get the string if we have a string wrapper object.
Handle<Object> string = object->IsJSValue()
? Handle<Object>(Handle<JSValue>::cast(object)->value())
: object;
return Smi::FromInt(String::cast(*string)->length());
}
// Use specialized code for getting the length of arrays.
if (object->IsJSArray() &&
name->Equals(isolate()->heap()->length_symbol())) {
Handle<Code> stub;
if (state == UNINITIALIZED) {
stub = pre_monomorphic_stub();
} else if (state == PREMONOMORPHIC) {
stub = isolate()->builtins()->LoadIC_ArrayLength();
} else if (state != MEGAMORPHIC) {
stub = megamorphic_stub();
}
if (!stub.is_null()) {
set_target(*stub);
#ifdef DEBUG
if (FLAG_trace_ic) PrintF("[LoadIC : +#length /array]\n");
#endif
}
return JSArray::cast(*object)->length();
}
// Use specialized code for getting prototype of functions.
if (object->IsJSFunction() &&
name->Equals(isolate()->heap()->prototype_symbol()) &&
Handle<JSFunction>::cast(object)->should_have_prototype()) {
Handle<Code> stub;
if (state == UNINITIALIZED) {
stub = pre_monomorphic_stub();
} else if (state == PREMONOMORPHIC) {
stub = isolate()->builtins()->LoadIC_FunctionPrototype();
} else if (state != MEGAMORPHIC) {
stub = megamorphic_stub();
}
if (!stub.is_null()) {
set_target(*stub);
#ifdef DEBUG
if (FLAG_trace_ic) PrintF("[LoadIC : +#prototype /function]\n");
#endif
}
return Accessors::FunctionGetPrototype(*object, 0);
}
}
// Check if the name is trivially convertible to an index and get
// the element if so.
uint32_t index;
if (name->AsArrayIndex(&index)) return object->GetElement(index);
// Named lookup in the object.
LookupResult lookup(isolate());
LookupForRead(object, name, &lookup);
// If we did not find a property, check if we need to throw an exception.
if (!lookup.IsFound()) {
if (IsContextual(object)) {
return ReferenceError("not_defined", name);
}
LOG(isolate(), SuspectReadEvent(*name, *object));
}
// Update inline cache and stub cache.
if (FLAG_use_ic) {
UpdateCaches(&lookup, state, object, name);
}
PropertyAttributes attr;
if (lookup.IsInterceptor() || lookup.IsHandler()) {
// Get the property.
Handle<Object> result =
Object::GetProperty(object, object, &lookup, name, &attr);
RETURN_IF_EMPTY_HANDLE(isolate(), result);
// If the property is not present, check if we need to throw an
// exception.
if (attr == ABSENT && IsContextual(object)) {
return ReferenceError("not_defined", name);
}
return *result;
}
// Get the property.
return object->GetProperty(*object, &lookup, *name, &attr);
}
void LoadIC::UpdateCaches(LookupResult* lookup,
State state,
Handle<Object> object,
Handle<String> name) {
// Bail out if the result is not cacheable.
if (!lookup->IsCacheable()) return;
// Loading properties from values is not common, so don't try to
// deal with non-JS objects here.
if (!object->IsJSObject()) return;
Handle<JSObject> receiver = Handle<JSObject>::cast(object);
if (HasNormalObjectsInPrototypeChain(isolate(), lookup, *object)) return;
// Compute the code stub for this load.
Handle<Code> code;
if (state == UNINITIALIZED) {
// This is the first time we execute this inline cache.
// Set the target to the pre monomorphic stub to delay
// setting the monomorphic state.
code = pre_monomorphic_stub();
} else if (!lookup->IsProperty()) {
// Nonexistent property. The result is undefined.
code = isolate()->stub_cache()->ComputeLoadNonexistent(name, receiver);
} else {
// Compute monomorphic stub.
Handle<JSObject> holder(lookup->holder());
switch (lookup->type()) {
case FIELD:
code = isolate()->stub_cache()->ComputeLoadField(
name, receiver, holder, lookup->GetFieldIndex());
break;
case CONSTANT_FUNCTION: {
Handle<JSFunction> constant(lookup->GetConstantFunction());
code = isolate()->stub_cache()->ComputeLoadConstant(
name, receiver, holder, constant);
break;
}
case NORMAL:
if (holder->IsGlobalObject()) {
Handle<GlobalObject> global = Handle<GlobalObject>::cast(holder);
Handle<JSGlobalPropertyCell> cell(global->GetPropertyCell(lookup));
code = isolate()->stub_cache()->ComputeLoadGlobal(
name, receiver, global, cell, lookup->IsDontDelete());
} else {
// There is only one shared stub for loading normalized
// properties. It does not traverse the prototype chain, so the
// property must be found in the receiver for the stub to be
// applicable.
if (!holder.is_identical_to(receiver)) return;
code = isolate()->stub_cache()->ComputeLoadNormal();
}
break;
case CALLBACKS: {
Handle<Object> callback(lookup->GetCallbackObject());
if (callback->IsAccessorInfo()) {
Handle<AccessorInfo> info = Handle<AccessorInfo>::cast(callback);
if (v8::ToCData<Address>(info->getter()) == 0) return;
if (!info->IsCompatibleReceiver(*receiver)) return;
code = isolate()->stub_cache()->ComputeLoadCallback(
name, receiver, holder, info);
} else if (callback->IsAccessorPair()) {
Handle<Object> getter(Handle<AccessorPair>::cast(callback)->getter());