Directly store the transition target on LookupResult in TransitionResult.

BUG=chromium:343964
LOG=N
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/170343003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19440 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/hydrogen-instructions.cc

@@ -4376,14 +4376,14 @@ HObjectAccess HObjectAccess::ForBackingStoreOffset(int offset,
 HObjectAccess HObjectAccess::ForField(Handle<Map> map,
                                       LookupResult* lookup,
                                       Handle<String> name) {
-  ASSERT(lookup->IsField() || lookup->IsTransitionToField(*map));
+  ASSERT(lookup->IsField() || lookup->IsTransitionToField());
   int index;
   Representation representation;
   if (lookup->IsField()) {
     index = lookup->GetLocalFieldIndexFromMap(*map);
     representation = lookup->representation();
   } else {
-    Map* transition = lookup->GetTransitionMapFromMap(*map);
+    Map* transition = lookup->GetTransitionTarget();
     int descriptor = transition->LastAdded();
     index = transition->instance_descriptors()->GetFieldIndex(descriptor) -
         map->inobject_properties();

src/hydrogen.cc

@@ -5555,8 +5555,7 @@ bool HOptimizedGraphBuilder::PropertyAccessInfo::CanAccessMonomorphic() {
   if (lookup_.IsPropertyCallbacks()) return true;
   Handle<Map> map = this->map();
   map->LookupTransition(NULL, *name_, &lookup_);
-  if (lookup_.IsTransitionToField(*map) && map->unused_property_fields() > 0) {
-    transition_ = handle(lookup_.GetTransitionMapFromMap(*map));
+  if (lookup_.IsTransitionToField() && map->unused_property_fields() > 0) {
     return true;
   }
   return false;

src/hydrogen.h

@@ -2408,7 +2408,7 @@ class HOptimizedGraphBuilder : public HGraphBuilder, public AstVisitor {
     Handle<JSObject> holder() { return holder_; }
     Handle<JSFunction> accessor() { return accessor_; }
     Handle<Object> constant() { return constant_; }
-    Handle<Object> transition() { return transition_; }
+    Handle<Map> transition() { return handle(lookup_.GetTransitionTarget()); }
     HObjectAccess access() { return access_; }
 
    private:
@@ -2435,7 +2435,6 @@ class HOptimizedGraphBuilder : public HGraphBuilder, public AstVisitor {
     Handle<JSFunction> accessor_;
     Handle<JSObject> api_holder_;
     Handle<Object> constant_;
-    Handle<Map> transition_;
     HObjectAccess access_;
   };
 

src/ic.cc

@@ -1134,8 +1134,7 @@ static bool LookupForWrite(Handle<JSObject> receiver,
   // receiver when trying to fetch extra information from the transition.
   receiver->map()->LookupTransition(*holder, *name, lookup);
   if (!lookup->IsTransition()) return false;
-  PropertyDetails target_details =
-      lookup->GetTransitionDetails(receiver->map());
+  PropertyDetails target_details = lookup->GetTransitionDetails();
   if (target_details.IsReadOnly()) return false;
 
   // If the value that's being stored does not fit in the field that the
@@ -1146,7 +1145,7 @@ static bool LookupForWrite(Handle<JSObject> receiver,
   // transition target.
   ASSERT(!receiver->map()->is_deprecated());
   if (!value->FitsRepresentation(target_details.representation())) {
-    Handle<Map> target(lookup->GetTransitionMapFromMap(receiver->map()));
+    Handle<Map> target(lookup->GetTransitionTarget());
     Map::GeneralizeRepresentation(
         target, target->LastAdded(),
         value->OptimalRepresentation(), FORCE_FIELD);
@@ -1319,12 +1318,8 @@ Handle<Code> StoreIC::CompileHandler(LookupResult* lookup,
     case TRANSITION: {
       // Explicitly pass in the receiver map since LookupForWrite may have
       // stored something else than the receiver in the holder.
-      Handle<Map> transition(
-          lookup->GetTransitionTarget(receiver->map()), isolate());
-      int descriptor = transition->LastAdded();
-
-      DescriptorArray* target_descriptors = transition->instance_descriptors();
-      PropertyDetails details = target_descriptors->GetDetails(descriptor);
+      Handle<Map> transition(lookup->GetTransitionTarget());
+      PropertyDetails details = transition->GetLastDescriptorDetails();
 
       if (details.type() == CALLBACKS || details.attributes() != NONE) break;
 

src/objects-inl.h

@@ -2497,6 +2497,11 @@ int DescriptorArray::SearchWithCache(Name* name, Map* map) {
 }
 
 
+PropertyDetails Map::GetLastDescriptorDetails() {
+  return instance_descriptors()->GetDetails(LastAdded());
+}
+
+
 void Map::LookupDescriptor(JSObject* holder,
                            Name* name,
                            LookupResult* result) {
@@ -2514,7 +2519,8 @@ void Map::LookupTransition(JSObject* holder,
     TransitionArray* transition_array = transitions();
     int number = transition_array->Search(name);
     if (number != TransitionArray::kNotFound) {
-      return result->TransitionResult(holder, number);
+      return result->TransitionResult(
+          holder, transition_array->GetTarget(number));
     }
   }
   result->NotFound();

src/objects.h

@@ -6088,6 +6088,8 @@ class Map: public HeapObject {
                                Name* name,
                                LookupResult* result);
 
+  inline PropertyDetails GetLastDescriptorDetails();
+
   // The size of transition arrays are limited so they do not end up in large
   // object space. Otherwise ClearNonLiveTransitions would leak memory while
   // applying in-place right trimming.

src/property.cc

@@ -35,6 +35,7 @@ void LookupResult::Iterate(ObjectVisitor* visitor) {
   LookupResult* current = this;  // Could be NULL.
   while (current != NULL) {
     visitor->VisitPointer(BitCast<Object**>(&current->holder_));
+    visitor->VisitPointer(BitCast<Object**>(&current->transition_));
     current = current->next_;
   }
 }
@@ -82,13 +83,13 @@ void LookupResult::Print(FILE* out) {
         case FIELD:
           PrintF(out, " -type = map transition\n");
           PrintF(out, " -map:\n");
-          GetTransitionMap()->Print(out);
+          GetTransitionTarget()->Print(out);
           PrintF(out, "\n");
           return;
         case CONSTANT:
           PrintF(out, " -type = constant property transition\n");
           PrintF(out, " -map:\n");
-          GetTransitionMap()->Print(out);
+          GetTransitionTarget()->Print(out);
           PrintF(out, "\n");
           return;
         case CALLBACKS:

src/property.h

@@ -184,6 +184,7 @@ class LookupResult BASE_EMBEDDED {
         next_(isolate->top_lookup_result()),
         lookup_type_(NOT_FOUND),
         holder_(NULL),
+        transition_(NULL),
         cacheable_(true),
         details_(NONE, NONEXISTENT, Representation::None()) {
     isolate->set_top_lookup_result(this);
@@ -199,6 +200,7 @@ class LookupResult BASE_EMBEDDED {
   void DescriptorResult(JSObject* holder, PropertyDetails details, int number) {
     lookup_type_ = DESCRIPTOR_TYPE;
     holder_ = holder;
+    transition_ = NULL;
     details_ = details;
     number_ = number;
   }
@@ -209,16 +211,18 @@ class LookupResult BASE_EMBEDDED {
     return value->FitsRepresentation(details_.representation());
   }
 
-  void TransitionResult(JSObject* holder, int number) {
+  void TransitionResult(JSObject* holder, Map* target) {
     lookup_type_ = TRANSITION_TYPE;
     details_ = PropertyDetails(NONE, TRANSITION, Representation::None());
     holder_ = holder;
-    number_ = number;
+    transition_ = target;
+    number_ = 0xAAAA;
   }
 
   void DictionaryResult(JSObject* holder, int entry) {
     lookup_type_ = DICTIONARY_TYPE;
     holder_ = holder;
+    transition_ = NULL;
     details_ = holder->property_dictionary()->DetailsAt(entry);
     number_ = entry;
   }
@@ -226,6 +230,7 @@ class LookupResult BASE_EMBEDDED {
   void HandlerResult(JSProxy* proxy) {
     lookup_type_ = HANDLER_TYPE;
     holder_ = proxy;
+    transition_ = NULL;
     details_ = PropertyDetails(NONE, HANDLER, Representation::Tagged());
     cacheable_ = false;
   }
@@ -233,6 +238,7 @@ class LookupResult BASE_EMBEDDED {
   void InterceptorResult(JSObject* holder) {
     lookup_type_ = INTERCEPTOR_TYPE;
     holder_ = holder;
+    transition_ = NULL;
     details_ = PropertyDetails(NONE, INTERCEPTOR, Representation::Tagged());
   }
 
@@ -240,6 +246,7 @@ class LookupResult BASE_EMBEDDED {
     lookup_type_ = NOT_FOUND;
     details_ = PropertyDetails(NONE, NONEXISTENT, Representation::None());
     holder_ = NULL;
+    transition_ = NULL;
   }
 
   JSObject* holder() const {
@@ -248,7 +255,7 @@ class LookupResult BASE_EMBEDDED {
   }
 
   JSProxy* proxy() const {
-    ASSERT(IsFound());
+    ASSERT(IsHandler());
     return JSProxy::cast(holder_);
   }
 
@@ -373,47 +380,21 @@ class LookupResult BASE_EMBEDDED {
     return NULL;
   }
 
-  Map* GetTransitionTarget(Map* map) const {
-    ASSERT(IsTransition());
-    TransitionArray* transitions = map->transitions();
-    return transitions->GetTarget(number_);
-  }
-
   Map* GetTransitionTarget() const {
-    return GetTransitionTarget(holder()->map());
-  }
-
-  PropertyDetails GetTransitionDetails(Map* map) const {
-    ASSERT(IsTransition());
-    TransitionArray* transitions = map->transitions();
-    return transitions->GetTargetDetails(number_);
+    return transition_;
   }
 
   PropertyDetails GetTransitionDetails() const {
-    return GetTransitionDetails(holder()->map());
-  }
-
-  bool IsTransitionToField(Map* map) const {
-    return IsTransition() && GetTransitionDetails(map).type() == FIELD;
-  }
-
-  bool IsTransitionToConstant(Map* map) const {
-    return IsTransition() && GetTransitionDetails(map).type() == CONSTANT;
-  }
-
-  Map* GetTransitionMap() const {
     ASSERT(IsTransition());
-    return Map::cast(GetValue());
+    return transition_->GetLastDescriptorDetails();
   }
 
-  Map* GetTransitionMapFromMap(Map* map) const {
-    ASSERT(IsTransition());
-    return map->transitions()->GetTarget(number_);
+  bool IsTransitionToField() const {
+    return IsTransition() && GetTransitionDetails().type() == FIELD;
   }
 
-  int GetTransitionIndex() const {
-    ASSERT(IsTransition());
-    return number_;
+  bool IsTransitionToConstant() const {
+    return IsTransition() && GetTransitionDetails().type() == CONSTANT;
   }
 
   int GetDescriptorIndex() const {
@@ -501,6 +482,7 @@ class LookupResult BASE_EMBEDDED {
   } lookup_type_;
 
   JSReceiver* holder_;
+  Map* transition_;
   int number_;
   bool cacheable_;
   PropertyDetails details_;

src/transitions-inl.h

@@ -160,9 +160,7 @@ void TransitionArray::SetTarget(int transition_number, Map* value) {
 
 PropertyDetails TransitionArray::GetTargetDetails(int transition_number) {
   Map* map = GetTarget(transition_number);
-  DescriptorArray* descriptors = map->instance_descriptors();
-  int descriptor = map->LastAdded();
-  return descriptors->GetDetails(descriptor);
+  return map->GetLastDescriptorDetails();
 }
 
 

test/mjsunit/regress/regress-lookup-transition.js

+// Copyright 2014 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.
+
+// Flags: --harmony-proxies --expose-gc
+
+var proxy = Proxy.create({ getPropertyDescriptor:function(key) {
+  gc();
+}});
+
+function f() { this.x = 23; }
+f.prototype = proxy;
+new f();
+new f();