TransitionArray now uses <is_data_property, name, attributes> tuple as a key, which allows to have …

src/transitions-inl.h

Index: src/transitions-inl.h
diff --git a/src/transitions-inl.h b/src/transitions-inl.h
index 087755d1bdde10f941d17e23f903a0660f5030b2..683301fab14aa146439a51c2352626f5e4236722 100644
--- a/src/transitions-inl.h
+++ b/src/transitions-inl.h
@@ -34,7 +34,7 @@ TransitionArray* TransitionArray::cast(Object* object) {
 
 
 bool TransitionArray::HasElementsTransition() {
-  return Search(GetHeap()->elements_transition_symbol()) != kNotFound;
+  return SearchSpecial(GetHeap()->elements_transition_symbol()) != kNotFound;
 }
 
 
@@ -140,7 +140,7 @@ Object* TransitionArray::GetTargetValue(int transition_number) {
 }
 
 
-int TransitionArray::Search(Name* name, int* out_insertion_index) {
+int TransitionArray::SearchName(Name* name, int* out_insertion_index) {
   if (IsSimpleTransition()) {
     Name* key = GetKey(kSimpleTransitionIndex);
     if (key->Equals(name)) return kSimpleTransitionIndex;
@@ -153,6 +153,73 @@ int TransitionArray::Search(Name* name, int* out_insertion_index) {
 }
 
 
+#ifdef DEBUG
+bool TransitionArray::IsSpecialTransition(Name* name) {
+  if (!name->IsSymbol()) return false;
+  Heap* heap = name->GetHeap();
+  return name == heap->frozen_symbol() ||
+         name == heap->elements_transition_symbol() ||
+         name == heap->observed_symbol();
+}
+#endif
+
+
+int TransitionArray::CompareKeys(Name* key1, uint32_t hash1,
+                                 bool is_data_property1,
+                                 PropertyAttributes attributes1, Name* key2,
+                                 uint32_t hash2, bool is_data_property2,
+                                 PropertyAttributes attributes2) {
+  int cmp = CompareNames(key1, hash1, key2, hash2);
+  if (cmp != 0) return cmp;
+
+  return CompareDetails(is_data_property1, attributes1, is_data_property2,
+                        attributes2);
+}
+
+
+int TransitionArray::CompareNames(Name* key1, uint32_t hash1, Name* key2,
+                                  uint32_t hash2) {
+  if (key1 != key2) {
+    // In case of hash collisions key1 is always "less" than key2.
+    return hash1 <= hash2 ? -1 : 1;
+  }
+
+  return 0;
+}
+
+
+int TransitionArray::CompareDetails(bool is_data_property1,
+                                    PropertyAttributes attributes1,
+                                    bool is_data_property2,
+                                    PropertyAttributes attributes2) {
+  if (is_data_property1 != is_data_property2) {
+    return static_cast<int>(is_data_property1) <
+                   static_cast<int>(is_data_property2)
+               ? -1
+               : 1;
+  }
+
+  if (attributes1 != attributes2) {
+    return static_cast<int>(attributes1) < static_cast<int>(attributes2) ? -1
+                                                                         : 1;
+  }
+
+  return 0;
+}
+
+
+PropertyDetails TransitionArray::GetTargetDetails(Name* name, Map* target) {
+  DCHECK(!IsSpecialTransition(name));
+  int descriptor = target->LastAdded();
+  DescriptorArray* descriptors = target->instance_descriptors();
+  if (!descriptors->GetKey(descriptor)->Equals(name)) {
+    descriptor = descriptors->SearchWithCache(name, target);
+    DCHECK_NE(kNotFound, descriptor);

[Toon Verwaest, 2014/11/04 10:50:50]

Mmh, this doesn't seem necessary. We shouldn't need to compare details ever when
you can't find it at the end. This is only true if you added a setter/getter to
an existing setter/getter. In such case, that's the only possible transition
under that name. If we are fetching such details, we're probably computing too
much stuff.

[Igor Sheludko, 2014/11/04 16:44:16]

Done. Now transitions always created for last added property. I had to disabl
the ability to reconfigure non-last accessor property. I'll address
reconfiguration in next CL.

+  }
+  return descriptors->GetDetails(descriptor);
+}
+
+
 void TransitionArray::NoIncrementalWriteBarrierSet(int transition_number,
                                                    Name* key,
                                                    Map* target) {