Promoting elements transitions to their own field.

src/factory.cc

Index: src/factory.cc
diff --git a/src/factory.cc b/src/factory.cc
index 1c29ea13b2b2dd8a17c5c179635f7ab8362f8c55..fa0c9b1a2bf3d7bc113b0f84120085020d669db6 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -114,7 +114,7 @@ Handle<ObjectHashTable> Factory::NewObjectHashTable(int at_least_space_for) {
 Handle<DescriptorArray> Factory::NewDescriptorArray(int number_of_descriptors) {
   ASSERT(0 <= number_of_descriptors);
   CALL_HEAP_FUNCTION(isolate(),
-                     DescriptorArray::Allocate(number_of_descriptors),
+                     DescriptorArray::Allocate(number_of_descriptors, false),
                      DescriptorArray);
 }
 
@@ -495,7 +495,7 @@ Handle<Map> Factory::CopyMap(Handle<Map> src,
 
 
 Handle<Map> Factory::CopyMapDropTransitions(Handle<Map> src) {
-  CALL_HEAP_FUNCTION(isolate(), src->CopyDropTransitions(), Map);
+  CALL_HEAP_FUNCTION(isolate(), src->CopyDropTransitions(false), Map);
 }
 
 
@@ -866,6 +866,21 @@ Handle<String> Factory::SymbolFromString(Handle<String> value) {
 }
 
 
+static int LinearSearchUnsorted(DescriptorArray* descriptor_array,
+                                String* name, int len) {
+  uint32_t hash = name->Hash();
+  for (int number = 0; number < len; number++) {
+    String* entry = descriptor_array->GetKey(number);
+    if (entry->Hash() == hash &&
+        name->Equals(entry) &&
+        !descriptor_array->IsNullDescriptor(number)) {
+      return number;
+    }
+  }
+  return DescriptorArray::kNotFound;
+}
+
+
 Handle<DescriptorArray> Factory::CopyAppendCallbackDescriptors(
     Handle<DescriptorArray> array,
     Handle<Object> descriptors) {
@@ -900,7 +915,7 @@ Handle<DescriptorArray> Factory::CopyAppendCallbackDescriptors(
     Handle<String> key =
         SymbolFromString(Handle<String>(String::cast(entry->name())));
     // Check if a descriptor with this name already exists before writing.
-    if (result->LinearSearch(*key, descriptor_count) ==
+    if (LinearSearchUnsorted(*result, *key, descriptor_count) ==

[danno, 2012/06/01 13:49:55]

Add a enum { EXPECT_SORTED, EXPECT_UNSORTED } and put both implementations in
LinearSearch on the descriptor that take the enum selector as another parameter.

[Toon Verwaest, 2012/06/04 09:17:48]

Done.

         DescriptorArray::kNotFound) {
       CallbacksDescriptor desc(*key, *entry, entry->property_attributes());
       result->Set(descriptor_count, &desc, witness);