Add MEGAMORPHIC state support for KeyedLoadIC

src/ic/ic.cc

 // 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"
@@ skipping 588 matching lines @@
   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::generic_stub(Isolate* isolate) {
+Handle<Code> KeyedLoadIC::megamorphic_stub(Isolate* isolate) {
   if (FLAG_compiled_keyed_generic_loads) {
     return KeyedLoadGenericStub(isolate).GetCode();
   } else {
-    return isolate->builtins()->KeyedLoadIC_Generic();
+    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;
@@ skipping 75 matching lines @@
 
   // 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(GENERIC);
       } else {
-        set_target(*KeyedLoadIC::generic_stub(isolate()));
+        set_target(*KeyedLoadIC::megamorphic_stub(isolate()));
       }
       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;
   }
@@ skipping 224 matching lines @@
     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(kind() == Code::KEYED_LOAD_IC ? GENERIC
-                                                           : MEGAMORPHIC);
+        ConfigureVectorState(MEGAMORPHIC);
       } else {
         set_target(*megamorphic_stub());
       }
     // Fall through.
     case MEGAMORPHIC:
       UpdateMegamorphicCache(*receiver_type(), *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;
-    case GENERIC:
-      // The generic keyed store stub re-uses store handlers, which can miss.
-      // That's ok, no reason to do anything.
-      DCHECK(target()->kind() == Code::KEYED_STORE_IC);
-      break;
   }
 }
 
 
 Handle<Code> LoadIC::initialize_stub(Isolate* isolate,
                                      ExtraICState extra_state) {
   if (FLAG_vector_ics) {
     return LoadICTrampolineStub(isolate, LoadICState(extra_state)).GetCode();
   }
 
@@ skipping 26 matching lines @@
   return initialize_stub(isolate);
 }
 
 
 Handle<Code> LoadIC::megamorphic_stub() {
   if (kind() == Code::LOAD_IC) {
     MegamorphicLoadStub stub(isolate(), LoadICState(extra_ic_state()));
     return stub.GetCode();
   } else {
     DCHECK_EQ(Code::KEYED_LOAD_IC, kind());
-    return KeyedLoadIC::generic_stub(isolate());
+    return KeyedLoadIC::megamorphic_stub(isolate());
   }
 }
 
 
 Handle<Code> LoadIC::pre_monomorphic_stub(Isolate* isolate,
                                           ExtraICState extra_state) {
   DCHECK(!FLAG_vector_ics);
   return PropertyICCompiler::ComputeLoad(isolate, PREMONOMORPHIC, extra_state);
 }
 
@@ skipping 48 matching lines @@
   } else {
     code = ComputeHandler(lookup);
   }
 
   PatchCache(lookup->name(), code);
   TRACE_IC("LoadIC", lookup->name());
 }
 
 
 void IC::UpdateMegamorphicCache(HeapType* type, Name* name, Code* code) {
-  // Megamorphic state isn't implemented for keyed loads currently.
-  if (kind() == Code::KEYED_LOAD_IC) return;
   Map* map = *TypeToMap(type, isolate());
   isolate()->stub_cache()->Set(name, map, code);
 }
 
 
 Handle<Code> IC::ComputeHandler(LookupIterator* lookup, Handle<Object> value) {
   bool receiver_is_holder =
       lookup->GetReceiver().is_identical_to(lookup->GetHolder<JSObject>());
   CacheHolderFlag flag;
   Handle<Map> stub_holder_map = IC::GetHandlerCacheHolder(
@@ skipping 257 matching lines @@
   }
 
   DCHECK(state() != GENERIC);
 
   // Determine the list of receiver maps that this call site has seen,
   // adding the map that was just encountered.
   if (!AddOneReceiverMapIfMissing(&target_receiver_maps, receiver_map)) {
     // If the miss wasn't due to an unseen map, a polymorphic stub
     // won't help, use the generic stub.
     TRACE_GENERIC_IC(isolate(), "KeyedLoadIC", "same map added twice");
-    return generic_stub();
+    return megamorphic_stub(isolate());
   }
 
   // If the maximum number of receiver maps has been exceeded, use the generic
   // version of the IC.
   if (target_receiver_maps.length() > kMaxKeyedPolymorphism) {
     TRACE_GENERIC_IC(isolate(), "KeyedLoadIC", "max polymorph exceeded");
-    return generic_stub();
+    return megamorphic_stub(isolate());
   }
 
   if (FLAG_vector_ics) {
     CodeHandleList handlers(target_receiver_maps.length());
     ElementHandlerCompiler compiler(isolate());
     compiler.CompileElementHandlers(&target_receiver_maps, &handlers);
     TypeHandleList types(target_receiver_maps.length());
     for (int i = 0; i < target_receiver_maps.length(); i++) {
       types.Add(HeapType::Class(target_receiver_maps.at(i), isolate()));
     }
     ConfigureVectorState(Handle<Name>::null(), &types, &handlers);
     return null_handle;
   }
 
   return PropertyICCompiler::ComputeKeyedLoadPolymorphic(&target_receiver_maps);
 }
 
 
 MaybeHandle<Object> KeyedLoadIC::Load(Handle<Object> object,
                                       Handle<Object> key) {
   if (MigrateDeprecated(object)) {
     Handle<Object> result;
     ASSIGN_RETURN_ON_EXCEPTION(
         isolate(), result, Runtime::GetObjectProperty(isolate(), object, key),
         Object);
     return result;
   }
 
   Handle<Object> load_handle;
-  Handle<Code> stub = generic_stub();
+  Handle<Code> stub = megamorphic_stub(isolate());
 
   // Check for non-string values that can be converted into an
   // internalized string directly or is representable as a smi.
   key = TryConvertKey(key, isolate());
 
   if (key->IsInternalizedString() || key->IsSymbol()) {
     ASSIGN_RETURN_ON_EXCEPTION(isolate(), load_handle,
                                LoadIC::Load(object, Handle<Name>::cast(key)),
                                Object);
   } else if (FLAG_use_ic && !object->IsAccessCheckNeeded()) {
     if (object->IsJSObject() || (object->IsString() && key->IsNumber())) {
       Handle<HeapObject> receiver = Handle<HeapObject>::cast(object);
       if (object->IsString() || !Object::ToSmi(isolate(), key).is_null()) {
         stub = LoadElementStub(receiver);
       }
     }
   }
 
   if (!UseVector()) {
     if (!is_target_set()) {
-      Code* generic = *generic_stub();
+      Code* generic = *megamorphic_stub(isolate());
       if (*stub == generic) {
         TRACE_GENERIC_IC(isolate(), "KeyedLoadIC", "set generic");
       }
 
       set_target(*stub);
       TRACE_IC("LoadIC", key);
     }
   } else {
     if (!is_vector_set() || stub.is_null()) {
-      Code* generic = *generic_stub();
+      Code* generic = *megamorphic_stub(isolate());
       if (!stub.is_null() && *stub == generic) {
         ConfigureVectorState(GENERIC);
         TRACE_GENERIC_IC(isolate(), "KeyedLoadIC", "set generic");
       }
 
       TRACE_IC("LoadIC", key);
     }
   }
 
   if (!load_handle.is_null()) return load_handle;
@@ skipping 1555 matching lines @@
 static const 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