[Isolates] Merge r 6300:6500 from bleeding_edge to isolates.

src/ic.cc

 // Copyright 2006-2009 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
@@ skipping 140 matching lines @@
         !current->IsJSGlobalProxy() &&
         !current->IsJSGlobalObject()) {
       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;
-
+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 MONOMORPHIC;
+    return false;
   } else if (cache_holder == PROTOTYPE_MAP &&
              receiver->GetPrototype()->IsNull()) {
     // IC::GetCodeCacheHolder is not applicable.
-    return MONOMORPHIC;
+    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) {
-    // 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;
-    }
+    map->RemoveFromCodeCache(String::cast(name), target, index);
+    return true;
+  }
 
-    // Remove the target from the code cache to avoid hitting the same
-    // invalid stub again.
-    map->RemoveFromCodeCache(String::cast(name), target, index);
+  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()) {
@@ skipping 138 matching lines @@
   PatchInlinedStore(address, HEAP->fixed_array_map());
 }
 
 
 void KeyedStoreIC::Clear(Address address, Code* target) {
   if (target->ic_state() == UNINITIALIZED) return;
   SetTargetAtAddress(address, initialize_stub());
 }
 
 
-Code* KeyedLoadIC::external_array_stub(JSObject::ElementsKind elements_kind) {
-  switch (elements_kind) {
-    case JSObject::EXTERNAL_BYTE_ELEMENTS:
-      return isolate()->builtins()->builtin(
-          Builtins::KeyedLoadIC_ExternalByteArray);
-    case JSObject::EXTERNAL_UNSIGNED_BYTE_ELEMENTS:
-      return isolate()->builtins()->builtin(
-          Builtins::KeyedLoadIC_ExternalUnsignedByteArray);
-    case JSObject::EXTERNAL_SHORT_ELEMENTS:
-      return isolate()->builtins()->builtin(
-          Builtins::KeyedLoadIC_ExternalShortArray);
-    case JSObject::EXTERNAL_UNSIGNED_SHORT_ELEMENTS:
-      return isolate()->builtins()->builtin(
-          Builtins::KeyedLoadIC_ExternalUnsignedShortArray);
-    case JSObject::EXTERNAL_INT_ELEMENTS:
-      return isolate()->builtins()->builtin(
-          Builtins::KeyedLoadIC_ExternalIntArray);
-    case JSObject::EXTERNAL_UNSIGNED_INT_ELEMENTS:
-      return isolate()->builtins()->builtin(
-          Builtins::KeyedLoadIC_ExternalUnsignedIntArray);
-    case JSObject::EXTERNAL_FLOAT_ELEMENTS:
-      return isolate()->builtins()->builtin(
-          Builtins::KeyedLoadIC_ExternalFloatArray);
-    default:
-      UNREACHABLE();
-      return NULL;
-  }
-}
-
-
-Code* KeyedStoreIC::external_array_stub(JSObject::ElementsKind elements_kind) {
-  switch (elements_kind) {
-    case JSObject::EXTERNAL_BYTE_ELEMENTS:
-      return isolate()->builtins()->builtin(
-          Builtins::KeyedStoreIC_ExternalByteArray);
-    case JSObject::EXTERNAL_UNSIGNED_BYTE_ELEMENTS:
-      return isolate()->builtins()->builtin(
-          Builtins::KeyedStoreIC_ExternalUnsignedByteArray);
-    case JSObject::EXTERNAL_SHORT_ELEMENTS:
-      return isolate()->builtins()->builtin(
-          Builtins::KeyedStoreIC_ExternalShortArray);
-    case JSObject::EXTERNAL_UNSIGNED_SHORT_ELEMENTS:
-      return isolate()->builtins()->builtin(
-          Builtins::KeyedStoreIC_ExternalUnsignedShortArray);
-    case JSObject::EXTERNAL_INT_ELEMENTS:
-      return isolate()->builtins()->builtin(
-          Builtins::KeyedStoreIC_ExternalIntArray);
-    case JSObject::EXTERNAL_UNSIGNED_INT_ELEMENTS:
-      return isolate()->builtins()->builtin(
-          Builtins::KeyedStoreIC_ExternalUnsignedIntArray);
-    case JSObject::EXTERNAL_FLOAT_ELEMENTS:
-      return isolate()->builtins()->builtin(
-          Builtins::KeyedStoreIC_ExternalFloatArray);
-    default:
-      UNREACHABLE();
-      return NULL;
-  }
-}
-
-
 static bool HasInterceptorGetter(JSObject* object) {
   return !object->GetNamedInterceptor()->getter()->IsUndefined();
 }
 
 
 static void LookupForRead(Object* object,
                           String* name,
                           LookupResult* lookup) {
   AssertNoAllocation no_gc;  // pointers must stay valid
 
@@ skipping 59 matching lines @@
   // 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);
   }
 
   if (object->IsString() || object->IsNumber() || object->IsBoolean()) {
     ReceiverToObject(object);
@@ skipping 25 matching lines @@
     // If the object does not have the requested property, check which
     // exception we need to throw.
     if (IsContextual(object)) {
       return ReferenceError("not_defined", name);
     }
     return TypeError("undefined_method", object, name);
   }
 
   // Lookup is valid: Update inline cache and stub cache.
   if (FLAG_use_ic) {
-    UpdateCaches(&lookup, state, object, name);
+    UpdateCaches(&lookup, state, extra_ic_state, object, name);
   }
 
   // Get the property.
   PropertyAttributes attr;
   Object* result;
   { MaybeObject* maybe_result =
         object->GetProperty(*object, &lookup, *name, &attr);
     if (!maybe_result->ToObject(&result)) return maybe_result;
   }
   if (lookup.type() == INTERCEPTOR) {
@@ skipping 29 matching lines @@
   // Try to find a suitable function delegate for the object at hand.
   result = TryCallAsFunction(result);
   MaybeObject* answer = result;
   if (!result->IsJSFunction()) {
     answer = TypeError("property_not_function", object, name);
   }
   return answer;
 }
 
 
+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 that there's the right wrapper in the receiver slot.
+        ASSERT(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 (*extra_ic_state == DEFAULT_STRING_STUB &&
+            argc >= 1 && args[1]->IsNumber()) {
+          double index;
+          if (args[1]->IsSmi()) {
+            index = Smi::cast(args[1])->value();
+          } else {
+            ASSERT(args[1]->IsHeapNumber());
+            index = DoubleToInteger(HeapNumber::cast(args[1])->value());
+          }
+          if (index < 0 || index >= string->length()) {
+            *extra_ic_state = STRING_INDEX_OUT_OF_BOUNDS;
+            return true;
+          }
+        }
+      }
+      break;
+    default:
+      return false;
+  }
+  return false;
+}
+
+
+MaybeObject* CallICBase::ComputeMonomorphicStub(
+    LookupResult* lookup,
+    State state,
+    Code::ExtraICState extra_ic_state,
+    Handle<Object> object,
+    Handle<String> name) {
+  int argc = target()->arguments_count();
+  InLoopFlag in_loop = target()->ic_in_loop();
+  MaybeObject* maybe_code = NULL;
+  switch (lookup->type()) {
+    case FIELD: {
+      int index = lookup->GetFieldIndex();
+      maybe_code = isolate()->stub_cache()->ComputeCallField(argc,
+                                                             in_loop,
+                                                             kind_,
+                                                             *name,
+                                                             *object,
+                                                             lookup->holder(),
+                                                             index);
+      break;
+    }
+    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.
+      JSFunction* function = lookup->GetConstantFunction();
+      maybe_code = 
+          isolate()->stub_cache()->ComputeCallConstant(argc,
+                                                       in_loop,
+                                                       kind_,
+                                                       extra_ic_state,
+                                                       *name,
+                                                       *object,
+                                                       lookup->holder(),
+                                                       function);
+      break;
+    }
+    case NORMAL: {
+      if (!object->IsJSObject()) return NULL;
+      Handle<JSObject> receiver = Handle<JSObject>::cast(object);
+
+      if (lookup->holder()->IsGlobalObject()) {
+        GlobalObject* global = GlobalObject::cast(lookup->holder());
+        JSGlobalPropertyCell* cell =
+            JSGlobalPropertyCell::cast(global->GetPropertyCell(lookup));
+        if (!cell->value()->IsJSFunction()) return NULL;
+        JSFunction* function = JSFunction::cast(cell->value());
+        maybe_code = isolate()->stub_cache()->ComputeCallGlobal(argc,
+                                                                in_loop,
+                                                                kind_,
+                                                                *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 (lookup->holder() != *receiver) return NULL;
+        maybe_code = isolate()->stub_cache()->ComputeCallNormal(argc,
+                                                                in_loop,
+                                                                kind_,
+                                                                *name,
+                                                                *receiver);
+      }
+      break;
+    }
+    case INTERCEPTOR: {
+      ASSERT(HasInterceptorGetter(lookup->holder()));
+      maybe_code = isolate()->stub_cache()->ComputeCallInterceptor(
+          argc,
+          kind_,
+          *name,
+          *object,
+          lookup->holder());
+      break;
+    }
+    default:
+      maybe_code = NULL;
+      break;
+  }
+  return maybe_code;
+}
+
+
 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();
   InLoopFlag in_loop = target()->ic_in_loop();
   MaybeObject* maybe_code = NULL;
-  Object* code;
+  bool had_proto_failure = false;
   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.
     maybe_code = isolate()->stub_cache()->ComputeCallPreMonomorphic(argc,
                                                                     in_loop,
                                                                     kind_);
   } else if (state == MONOMORPHIC) {
-    maybe_code = isolate()->stub_cache()->ComputeCallMegamorphic(argc,
-                                                                 in_loop,
-                                                                 kind_);
+    if (kind_ == Code::CALL_IC &&
+        TryUpdateExtraICState(lookup, object, &extra_ic_state)) {
+      maybe_code = ComputeMonomorphicStub(lookup,
+                                          state,
+                                          extra_ic_state,
+                                          object,
+                                          name);
+    } else if (kind_ == Code::CALL_IC &&
+               TryRemoveInvalidPrototypeDependentStub(target(),
+                                                      *object,
+                                                      *name)) {
+      had_proto_failure = true;
+      maybe_code = ComputeMonomorphicStub(lookup,
+                                          state,
+                                          extra_ic_state,
+                                          object,
+                                          name);
+    } else {
+      maybe_code = isolate()->stub_cache()->ComputeCallMegamorphic(argc,
+                                                                   in_loop,
+                                                                   kind_);
+    }
   } else {
-    // Compute monomorphic stub.
-    switch (lookup->type()) {
-      case FIELD: {
-        int index = lookup->GetFieldIndex();
-        maybe_code = isolate()->stub_cache()->ComputeCallField(argc,
-                                                               in_loop,
-                                                               kind_,
-                                                               *name,
-                                                               *object,
-                                                               lookup->holder(),
-                                                               index);
-        break;
-      }
-      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.
-        JSFunction* function = lookup->GetConstantFunction();
-        maybe_code = isolate()->stub_cache()->ComputeCallConstant(
-            argc,
-            in_loop,
-            kind_,
-            *name,
-            *object,
-            lookup->holder(),
-            function);
-        break;
-      }
-      case NORMAL: {
-        if (!object->IsJSObject()) return;
-        Handle<JSObject> receiver = Handle<JSObject>::cast(object);
-
-        if (lookup->holder()->IsGlobalObject()) {
-          GlobalObject* global = GlobalObject::cast(lookup->holder());
-          JSGlobalPropertyCell* cell =
-              JSGlobalPropertyCell::cast(global->GetPropertyCell(lookup));
-          if (!cell->value()->IsJSFunction()) return;
-          JSFunction* function = JSFunction::cast(cell->value());
-          maybe_code = isolate()->stub_cache()->ComputeCallGlobal(argc,
-                                                                  in_loop,
-                                                                  kind_,
-                                                                  *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 (lookup->holder() != *receiver) return;
-          maybe_code = isolate()->stub_cache()->ComputeCallNormal(argc,
-                                                                  in_loop,
-                                                                  kind_,
-                                                                  *name,
-                                                                  *receiver);
-        }
-        break;
-      }
-      case INTERCEPTOR: {
-        ASSERT(HasInterceptorGetter(lookup->holder()));
-        maybe_code = isolate()->stub_cache()->ComputeCallInterceptor(
-            argc,
-            kind_,
-            *name,
-            *object,
-            lookup->holder());
-        break;
-      }
-      default:
-        return;
-    }
+    maybe_code = ComputeMonomorphicStub(lookup,
+                                        state,
+                                        extra_ic_state,
+                                        object,
+                                        name);
   }
 
   // If we're unable to compute the stub (not enough memory left), we
   // simply avoid updating the caches.
+  Object* code;
   if (maybe_code == NULL || !maybe_code->ToObject(&code)) 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::cast(code));
   } else if (state == MEGAMORPHIC) {
     // Cache code holding map should be consistent with
     // GenerateMonomorphicCacheProbe. It is not the map which holds the stub.
     Map* map = JSObject::cast(object->IsJSObject() ? *object :
                               object->GetPrototype())->map();
 
     // Update the stub cache.
     isolate()->stub_cache()->Set(*name, map, Code::cast(code));
   }
 
+  USE(had_proto_failure);
 #ifdef DEBUG
+  if (had_proto_failure) state = MONOMORPHIC_PROTOTYPE_FAILURE;
   TraceIC(kind_ == Code::CALL_IC ? "CallIC" : "KeyedCallIC",
       name, state, target(), in_loop ? " (in-loop)" : "");
 #endif
 }
 
 
 MaybeObject* KeyedCallIC::LoadFunction(State state,
                                        Handle<Object> object,
                                        Handle<Object> key) {
   if (key->IsSymbol()) {
-    return CallICBase::LoadFunction(state, object, Handle<String>::cast(key));
+    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 (object->IsString() || object->IsNumber() || object->IsBoolean()) {
     ReceiverToObject(object);
   }
 
@@ skipping 38 matching lines @@
 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) {
+    Code* non_monomorphic_stub =
+        (state == UNINITIALIZED) ? pre_monomorphic_stub() : megamorphic_stub();
+
     // 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())) {
       HandleScope scope(isolate());
+#ifdef DEBUG
+      if (FLAG_trace_ic) PrintF("[LoadIC : +#length /string]\n");
+#endif
+      if (state == PREMONOMORPHIC) {
+        if (object->IsString()) {
+          Map* map = HeapObject::cast(*object)->map();
+          const int offset = String::kLengthOffset;
+          PatchInlinedLoad(address(), map, offset);
+          set_target(isolate()->builtins()->builtin(
+              Builtins::LoadIC_StringLength));
+        } else {
+          set_target(isolate()->builtins()->builtin(
+              Builtins::LoadIC_StringWrapperLength));
+        }
+      } else if (state == MONOMORPHIC && object->IsStringWrapper()) {
+        set_target(isolate()->builtins()->builtin(
+            Builtins::LoadIC_StringWrapperLength));
+      } else {
+        set_target(non_monomorphic_stub);
+      }
       // Get the string if we have a string wrapper object.
       if (object->IsJSValue()) {
         object = Handle<Object>(Handle<JSValue>::cast(object)->value(),
                                 isolate());
       }
-#ifdef DEBUG
-      if (FLAG_trace_ic) PrintF("[LoadIC : +#length /string]\n");
-#endif
-      Map* map = HeapObject::cast(*object)->map();
-      if (object->IsString()) {
-        const int offset = String::kLengthOffset;
-        PatchInlinedLoad(address(), map, offset);
-      }
-
-      Code* target = NULL;
-      target = isolate()->builtins()->builtin(
-          Builtins::LoadIC_StringLength);
-      set_target(target);
       return Smi::FromInt(String::cast(*object)->length());
     }
 
     // Use specialized code for getting the length of arrays.
     if (object->IsJSArray() &&
         name->Equals(isolate()->heap()->length_symbol())) {
 #ifdef DEBUG
       if (FLAG_trace_ic) PrintF("[LoadIC : +#length /array]\n");
 #endif
-      Map* map = HeapObject::cast(*object)->map();
-      const int offset = JSArray::kLengthOffset;
-      PatchInlinedLoad(address(), map, offset);
-
-      Code* target = isolate()->builtins()->builtin(
-          Builtins::LoadIC_ArrayLength);
-      set_target(target);
+      if (state == PREMONOMORPHIC) {
+        Map* map = HeapObject::cast(*object)->map();
+        const int offset = JSArray::kLengthOffset;
+        PatchInlinedLoad(address(), map, offset);
+        set_target(isolate()->builtins()->builtin(
+            Builtins::LoadIC_ArrayLength));
+      } else {
+        set_target(non_monomorphic_stub);
+      }
       return JSArray::cast(*object)->length();
     }
 
     // Use specialized code for getting prototype of functions.
     if (object->IsJSFunction() &&
         name->Equals(isolate()->heap()->prototype_symbol()) &&
         JSFunction::cast(*object)->should_have_prototype()) {
 #ifdef DEBUG
       if (FLAG_trace_ic) PrintF("[LoadIC : +#prototype /function]\n");
 #endif
-      Code* target = isolate()->builtins()->builtin(
-          Builtins::LoadIC_FunctionPrototype);
-      set_target(target);
+      if (state == PREMONOMORPHIC) {
+        set_target(isolate()->builtins()->builtin(
+            Builtins::LoadIC_FunctionPrototype));
+      } else {
+        set_target(non_monomorphic_stub);
+      }
       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.
@@ skipping 205 matching lines @@
   if (key->IsSymbol()) {
     Handle<String> name = Handle<String>::cast(key);
 
     // 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) {
+      // TODO(1073): don't ignore the current stub state.
+
       // Use specialized code for getting the length of strings.
       if (object->IsString() &&
           name->Equals(isolate()->heap()->length_symbol())) {
         Handle<String> string = Handle<String>::cast(object);
         Object* code = NULL;
         { MaybeObject* maybe_code =
               isolate()->stub_cache()->ComputeKeyedLoadStringLength(*name,
                                                                     *string);
           if (!maybe_code->ToObject(&code)) return maybe_code;
         }
@@ skipping 88 matching lines @@
   // the global object).
   bool use_ic = FLAG_use_ic && !object->IsAccessCheckNeeded();
 
   if (use_ic) {
     Code* stub = generic_stub();
     if (object->IsString() && key->IsNumber()) {
       stub = string_stub();
     } else if (object->IsJSObject()) {
       Handle<JSObject> receiver = Handle<JSObject>::cast(object);
       if (receiver->HasExternalArrayElements()) {
-        stub = external_array_stub(receiver->GetElementsKind());
+        MaybeObject* probe =
+            isolate()->stub_cache()->ComputeKeyedLoadOrStoreExternalArray(
+                *receiver, false);
+        stub =
+            probe->IsFailure() ? NULL : Code::cast(probe->ToObjectUnchecked());
       } else if (receiver->HasIndexedInterceptor()) {
         stub = indexed_interceptor_stub();
       } else if (state == UNINITIALIZED &&
                  key->IsSmi() &&
                  receiver->map()->has_fast_elements()) {
-        StubCache* stub_cache = isolate()->stub_cache();
-        MaybeObject* probe = stub_cache->ComputeKeyedLoadSpecialized(*receiver);
+        MaybeObject* probe = 
+            isolate()->stub_cache()->ComputeKeyedLoadSpecialized(*receiver);
         stub =
             probe->IsFailure() ? NULL : Code::cast(probe->ToObjectUnchecked());
       }
     }
     if (stub != NULL) set_target(stub);
 
 #ifdef DEBUG
     TraceIC("KeyedLoadIC", key, state, target());
 #endif  // DEBUG
 
@@ skipping 368 matching lines @@
   // Do not use ICs for objects that require access checks (including
   // the global object).
   bool use_ic = FLAG_use_ic && !object->IsAccessCheckNeeded();
   ASSERT(!(use_ic && object->IsJSGlobalProxy()));
 
   if (use_ic) {
     Code* stub = generic_stub();
     if (object->IsJSObject()) {
       Handle<JSObject> receiver = Handle<JSObject>::cast(object);
       if (receiver->HasExternalArrayElements()) {
-        stub = external_array_stub(receiver->GetElementsKind());
+        MaybeObject* probe =
+            isolate()->stub_cache()->ComputeKeyedLoadOrStoreExternalArray(
+                *receiver, true);
+        stub =
+            probe->IsFailure() ? NULL : Code::cast(probe->ToObjectUnchecked());
       } else if (state == UNINITIALIZED &&
                  key->IsSmi() &&
                  receiver->map()->has_fast_elements()) {
         MaybeObject* probe =
             isolate()->stub_cache()->ComputeKeyedStoreSpecialized(*receiver);
         stub =
             probe->IsFailure() ? NULL : Code::cast(probe->ToObjectUnchecked());
       }
     }
     if (stub != NULL) set_target(stub);
@@ skipping 94 matching lines @@
 }
 
 
 // Used from ic-<arch>.cc.
 MUST_USE_RESULT MaybeObject* CallIC_Miss(RUNTIME_CALLING_CONVENTION) {
   RUNTIME_GET_ISOLATE;
   NoHandleAllocation na;
   ASSERT(args.length() == 2);
   CallIC ic(isolate);
   IC::State state = IC::StateFrom(ic.target(), args[0], args[1]);
+  Code::ExtraICState extra_ic_state = ic.target()->extra_ic_state();
+  MaybeObject* maybe_result = ic.LoadFunction(state,
+                                              extra_ic_state,
+                                              args.at<Object>(0),
+                                              args.at<String>(1));
   Object* result;
-  { MaybeObject* maybe_result =
-       ic.LoadFunction(state, args.at<Object>(0), args.at<String>(1));
-    if (!maybe_result->ToObject(&result)) return maybe_result;
-  }
+  if (!maybe_result->ToObject(&result)) return maybe_result;
 
   // The first time the inline cache is updated may be the first time the
   // function it references gets called.  If the function was lazily compiled
   // then the first call will trigger a compilation.  We check for this case
   // and we do the compilation immediately, instead of waiting for the stub
   // currently attached to the JSFunction object to trigger compilation.  We
   // do this in the case where we know that the inline cache is inside a loop,
   // because then we know that we want to optimize the function.
   if (!result->IsJSFunction() || JSFunction::cast(result)->is_compiled()) {
     return result;
@@ skipping 382 matching lines @@
     }
   }
   if (type == TRBinaryOpIC::INT32 &&
       previous_type == TRBinaryOpIC::INT32) {
     // We must be here because an operation on two INT32 types overflowed.
     result_type = TRBinaryOpIC::HEAP_NUMBER;
   }
 
   Handle<Code> code = GetTypeRecordingBinaryOpStub(key, type, result_type);
   if (!code.is_null()) {
-    TRBinaryOpIC ic(isolate);
-    ic.patch(*code);
     if (FLAG_trace_ic) {
       PrintF("[TypeRecordingBinaryOpIC (%s->(%s->%s))#%s]\n",
              TRBinaryOpIC::GetName(previous_type),
              TRBinaryOpIC::GetName(type),
              TRBinaryOpIC::GetName(result_type),
              Token::Name(op));
     }
+    TRBinaryOpIC ic(isolate);
+    ic.patch(*code);
 
     // Activate inlined smi code.
     if (previous_type == TRBinaryOpIC::UNINITIALIZED) {
       PatchInlinedSmiCode(ic.address());
     }
   }
 
   Handle<JSBuiltinsObject> builtins = Handle<JSBuiltinsObject>(
       isolate->thread_local_top()->context_->builtins(), isolate);
   Object* builtin = NULL;  // Initialization calms down the compiler.
@@ skipping 112 matching lines @@
 #undef ADDR
 };
 
 
 Address IC::AddressFromUtilityId(IC::UtilityId id) {
   return IC_utilities[id];
 }
 
 
 } }  // namespace v8::internal