ic.cc.svn-base

Google浏览器V8内核代码

      case INTERCEPTOR: {
        code = StubCache::ComputeKeyedLoadInterceptor(*name, *receiver,
                                                      lookup->holder());
        break;
      }
      default: {
        // Always rewrite to the generic case so that we do not
        // repeatedly try to rewrite.
        code = generic_stub();
        break;
      }
    }
  }

  // If we're unable to compute the stub (not enough memory left), we
  // simply avoid updating the caches.
  if (code->IsFailure()) return;

  // Patch the call site depending on the state of the cache.  Make
  // sure to always rewrite from monomorphic to megamorphic.
  ASSERT(state != MONOMORPHIC_PROTOTYPE_FAILURE);
  if (state == UNINITIALIZED || state == PREMONOMORPHIC) {
    set_target(Code::cast(code));
  } else if (state == MONOMORPHIC) {
    set_target(megamorphic_stub());
  }

#ifdef DEBUG
  TraceIC("KeyedLoadIC", name, state, target());
#endif
}


Object* StoreIC::Store(State state,
                       Handle<Object> object,
                       Handle<String> name,
                       Handle<Object> value) {
  // If the object is undefined or null it's illegal to try to set any
  // properties on it; throw a TypeError in that case.
  if (object->IsUndefined() || object->IsNull()) {
    return TypeError("non_object_property_store", object, name);
  }

  // Ignore stores where the receiver is not a JSObject.
  if (!object->IsJSObject()) return *value;
  Handle<JSObject> receiver = Handle<JSObject>::cast(object);

  // Check if the given name is an array index.
  uint32_t index;
  if (name->AsArrayIndex(&index)) {
    HandleScope scope;
    Handle<Object> result = SetElement(receiver, index, value);
    if (result.is_null()) return Failure::Exception();
    return *value;
  }

  // Lookup the property locally in the receiver.
  LookupResult lookup;
  receiver->LocalLookup(*name, &lookup);

  // Update inline cache and stub cache.
  if (FLAG_use_ic && lookup.IsLoaded()) {
    UpdateCaches(&lookup, state, receiver, name, value);
  }

  // Set the property.
  return receiver->SetProperty(*name, *value, NONE);
}


void StoreIC::UpdateCaches(LookupResult* lookup,
                           State state,
                           Handle<JSObject> receiver,
                           Handle<String> name,
                           Handle<Object> value) {
  ASSERT(lookup->IsLoaded());
  // Bail out if we didn't find a result.
  if (!lookup->IsValid() || !lookup->IsCacheable()) return;

  // If the property is read-only, we leave the IC in its current
  // state.
  if (lookup->IsReadOnly()) return;

  // If the property has a non-field type allowing map transitions
  // where there is extra room in the object, we leave the IC in its
  // current state.
  PropertyType type = lookup->type();

  // Compute the code stub for this store; used for rewriting to
  // monomorphic state and making sure that the code stub is in the
  // stub cache.
  Object* code = NULL;
  switch (type) {
    case FIELD: {
      code = StubCache::ComputeStoreField(*name, *receiver,
                                          lookup->GetFieldIndex());
      break;
    }
    case MAP_TRANSITION: {
      if (lookup->GetAttributes() != NONE) return;
      if (receiver->map()->unused_property_fields() == 0) return;
      HandleScope scope;
      ASSERT(type == MAP_TRANSITION &&
             (receiver->map()->unused_property_fields() > 0));
      Handle<Map> transition(lookup->GetTransitionMap());
      int index = transition->PropertyIndexFor(*name);
      code = StubCache::ComputeStoreField(*name, *receiver, index, *transition);
      break;
    }
    case CALLBACKS: {
      if (!lookup->GetCallbackObject()->IsAccessorInfo()) return;
      AccessorInfo* callback = AccessorInfo::cast(lookup->GetCallbackObject());
      if (v8::ToCData<Address>(callback->setter()) == 0) return;
      code = StubCache::ComputeStoreCallback(*name, *receiver, callback);
      break;
    }
    case INTERCEPTOR: {
      code = StubCache::ComputeStoreInterceptor(*name, *receiver);
      break;
    }
    default:
      return;
  }

  // If we're unable to compute the stub (not enough memory left), we
  // simply avoid updating the caches.
  if (code->IsFailure()) return;

  // Patch the call site depending on the state of the cache.
  if (state == UNINITIALIZED || state == MONOMORPHIC_PROTOTYPE_FAILURE) {
    set_target(Code::cast(code));
  } else if (state == MONOMORPHIC) {
    set_target(megamorphic_stub());
  }

#ifdef DEBUG
  TraceIC("StoreIC", name, state, target());
#endif
}


Object* KeyedStoreIC::Store(State state,
                            Handle<Object> object,
                            Handle<Object> key,
                            Handle<Object> value) {
  if (key->IsSymbol()) {
    Handle<String> name = Handle<String>::cast(key);

    // If the object is undefined or null it's illegal to try to set any
    // properties on it; throw a TypeError in that case.
    if (object->IsUndefined() || object->IsNull()) {
      return TypeError("non_object_property_store", object, name);
    }

    // Ignore stores where the receiver is not a JSObject.
    if (!object->IsJSObject()) return *value;
    Handle<JSObject> receiver = Handle<JSObject>::cast(object);

    // Check if the given name is an array index.
    uint32_t index;
    if (name->AsArrayIndex(&index)) {
      HandleScope scope;
      Handle<Object> result = SetElement(receiver, index, value);
      if (result.is_null()) return Failure::Exception();
      return *value;
    }

    // Lookup the property locally in the receiver.
    LookupResult lookup;
    receiver->LocalLookup(*name, &lookup);

    // Update inline cache and stub cache.
    if (FLAG_use_ic && lookup.IsLoaded()) {
      UpdateCaches(&lookup, state, receiver, name, value);
    }

    // Set the property.
    return receiver->SetProperty(*name, *value, NONE);
  }

  // Do not use ICs for objects that require access checks (including
  // the global object).
  bool use_ic = FLAG_use_ic && !object->IsAccessCheckNeeded();

  if (use_ic) set_target(generic_stub());

  // Set the property.
  return Runtime::SetObjectProperty(object, key, value, NONE);
}


void KeyedStoreIC::UpdateCaches(LookupResult* lookup,
                                State state,
                                Handle<JSObject> receiver,
                                Handle<String> name,
                                Handle<Object> value) {
  ASSERT(lookup->IsLoaded());
  // Bail out if we didn't find a result.
  if (!lookup->IsValid() || !lookup->IsCacheable()) return;

  // If the property is read-only, we leave the IC in its current
  // state.
  if (lookup->IsReadOnly()) return;

  // If the property has a non-field type allowing map transitions
  // where there is extra room in the object, we leave the IC in its
  // current state.
  PropertyType type = lookup->type();

  // Compute the code stub for this store; used for rewriting to
  // monomorphic state and making sure that the code stub is in the
  // stub cache.
  Object* code = NULL;

  switch (type) {
    case FIELD: {
      code = StubCache::ComputeKeyedStoreField(*name, *receiver,
                                               lookup->GetFieldIndex());
      break;
    }
    case MAP_TRANSITION: {
      if (lookup->GetAttributes() == NONE) {
        if (receiver->map()->unused_property_fields() == 0) return;
        HandleScope scope;
        ASSERT(type == MAP_TRANSITION &&
               (receiver->map()->unused_property_fields() > 0));
        Handle<Map> transition(lookup->GetTransitionMap());
        int index = transition->PropertyIndexFor(*name);
        code = StubCache::ComputeKeyedStoreField(*name, *receiver,
                                                 index, *transition);
        break;
      }
      // fall through.
    }
    default: {
      // Always rewrite to the generic case so that we do not
      // repeatedly try to rewrite.
      code = generic_stub();
      break;
    }
  }

  // If we're unable to compute the stub (not enough memory left), we
  // simply avoid updating the caches.
  if (code->IsFailure()) return;

  // Patch the call site depending on the state of the cache.  Make
  // sure to always rewrite from monomorphic to megamorphic.
  ASSERT(state != MONOMORPHIC_PROTOTYPE_FAILURE);
  if (state == UNINITIALIZED || state == PREMONOMORPHIC) {
    set_target(Code::cast(code));
  } else if (state == MONOMORPHIC) {
    set_target(megamorphic_stub());
  }

#ifdef DEBUG
  TraceIC("KeyedStoreIC", name, state, target());
#endif
}


// ----------------------------------------------------------------------------
// Static IC stub generators.
//

// Used from ic_<arch>.cc.
Object* CallIC_Miss(Arguments args) {
  NoHandleAllocation na;
  ASSERT(args.length() == 2);
  CallIC ic;
  IC::State state = IC::StateFrom(ic.target(), args[0]);
  return ic.LoadFunction(state, args.at<Object>(0), args.at<String>(1));
}


void CallIC::GenerateInitialize(MacroAssembler* masm, int argc) {
  Generate(masm, argc, ExternalReference(IC_Utility(kCallIC_Miss)));
}


void CallIC::GeneratePreMonomorphic(MacroAssembler* masm, int argc) {
  Generate(masm, argc, ExternalReference(IC_Utility(kCallIC_Miss)));
}


void CallIC::GenerateMiss(MacroAssembler* masm, int argc) {
  Generate(masm, argc, ExternalReference(IC_Utility(kCallIC_Miss)));
}


// Used from ic_<arch>.cc.
Object* LoadIC_Miss(Arguments args) {
  NoHandleAllocation na;
  ASSERT(args.length() == 2);
  LoadIC ic;
  IC::State state = IC::StateFrom(ic.target(), args[0]);
  return ic.Load(state, args.at<Object>(0), args.at<String>(1));
}


void LoadIC::GenerateInitialize(MacroAssembler* masm) {
  Generate(masm, ExternalReference(IC_Utility(kLoadIC_Miss)));
}


void LoadIC::GeneratePreMonomorphic(MacroAssembler* masm) {
  Generate(masm, ExternalReference(IC_Utility(kLoadIC_Miss)));
}


// Used from ic_<arch>.cc
Object* KeyedLoadIC_Miss(Arguments args) {
  NoHandleAllocation na;
  ASSERT(args.length() == 2);
  KeyedLoadIC ic;
  IC::State state = IC::StateFrom(ic.target(), args[0]);
  return ic.Load(state, args.at<Object>(0), args.at<Object>(1));
}


void KeyedLoadIC::GenerateInitialize(MacroAssembler* masm) {
  Generate(masm, ExternalReference(IC_Utility(kKeyedLoadIC_Miss)));
}


void KeyedLoadIC::GeneratePreMonomorphic(MacroAssembler* masm) {
  Generate(masm, ExternalReference(IC_Utility(kKeyedLoadIC_Miss)));
}


// Used from ic_<arch>.cc.
Object* StoreIC_Miss(Arguments args) {
  NoHandleAllocation na;
  ASSERT(args.length() == 3);
  StoreIC ic;
  IC::State state = IC::StateFrom(ic.target(), args[0]);
  return ic.Store(state, args.at<Object>(0), args.at<String>(1),
                  args.at<Object>(2));
}


void StoreIC::GenerateInitialize(MacroAssembler* masm) {
  Generate(masm, ExternalReference(IC_Utility(kStoreIC_Miss)));
}


void StoreIC::GenerateMiss(MacroAssembler* masm) {
  Generate(masm, ExternalReference(IC_Utility(kStoreIC_Miss)));
}


// Used from ic_<arch>.cc.
Object* KeyedStoreIC_Miss(Arguments args) {
  NoHandleAllocation na;
  ASSERT(args.length() == 3);
  KeyedStoreIC ic;
  IC::State state = IC::StateFrom(ic.target(), args[0]);
  return ic.Store(state, args.at<Object>(0), args.at<Object>(1),
                  args.at<Object>(2));
}


void KeyedStoreIC::GenerateInitialize(MacroAssembler* masm) {
  Generate(masm, ExternalReference(IC_Utility(kKeyedStoreIC_Miss)));
}


void KeyedStoreIC::GenerateMiss(MacroAssembler* masm) {
  Generate(masm, ExternalReference(IC_Utility(kKeyedStoreIC_Miss)));
}


static Address IC_utilities[] = {
#define ADDR(name) FUNCTION_ADDR(name),
    IC_UTIL_LIST(ADDR)
    NULL
#undef ADDR
};


Address IC::AddressFromUtilityId(IC::UtilityId id) {
  return IC_utilities[id];
}


} }  // namespace v8::internal