Fix redundant map allocation

src/factory.cc

 // 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.
 
 #include "src/factory.h"
 
 #include "src/allocation-site-scopes.h"
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
 #include "src/conversions.h"
@@ skipping 2366 matching lines @@
   }
   *is_result_from_cache = true;
   if (number_of_properties == 0) {
     // Reuse the initial map of the Object function if the literal has no
     // predeclared properties, or the strong map if strong.
     return handle(is_strong
                       ? context->js_object_strong_map()
                       : context->object_function()->initial_map(), isolate());
   }
 
-  // Create a new map and add it to the cache.
-  Handle<Map> map = Map::Create(isolate(), number_of_properties);
   int cache_index = number_of_properties - 1;
-  Handle<FixedArray> cache;
-  if (is_strong) {
-    map->set_is_strong();
-    if (context->strong_map_cache()->IsUndefined()) {
-      // Allocate the new map cache for the native context.
-      Handle<FixedArray> new_cache = NewFixedArray(kMapCacheSize, TENURED);
-      context->set_strong_map_cache(*new_cache);
+  Handle<Object> maybe_cache(is_strong ? context->strong_map_cache()
+                                       : context->map_cache(), isolate());
+  if (maybe_cache->IsUndefined()) {
+    // Allocate the new map cache for the native context.
+    maybe_cache = NewFixedArray(kMapCacheSize, TENURED);
+    if (is_strong) {
+      context->set_strong_map_cache(*maybe_cache);
+    } else {
+      context->set_map_cache(*maybe_cache);
     }
+  } else {
     // Check to see whether there is a matching element in the cache.
-    cache = handle(FixedArray::cast(context->strong_map_cache()));
-  } else {
-    if (context->map_cache()->IsUndefined()) {
-      // Allocate the new map cache for the native context.
-      Handle<FixedArray> new_cache = NewFixedArray(kMapCacheSize, TENURED);
-      context->set_map_cache(*new_cache);
-    }
-    // Check to see whether there is a matching element in the cache.
-    cache = handle(FixedArray::cast(context->map_cache()));
-  }
-  {
+    Handle<FixedArray> cache = Handle<FixedArray>::cast(maybe_cache);
     Object* result = cache->get(cache_index);
     if (result->IsWeakCell()) {
       WeakCell* cell = WeakCell::cast(result);
       if (!cell->cleared()) {
         return handle(Map::cast(cell->value()), isolate());
       }
     }
   }
+  // Create a new map and add it to the cache.
+  Handle<FixedArray> cache = Handle<FixedArray>::cast(maybe_cache);
+  Handle<Map> map = Map::Create(isolate(), number_of_properties);
+  if (is_strong) map->set_is_strong();
   Handle<WeakCell> cell = NewWeakCell(map);
   cache->set(cache_index, *cell);
   return map;
 }
 
 
 void Factory::SetRegExpAtomData(Handle<JSRegExp> regexp,
                                 JSRegExp::Type type,
                                 Handle<String> source,
                                 JSRegExp::Flags flags,
@@ skipping 36 matching lines @@
   return Handle<Object>::null();
 }
 
 
 Handle<Object> Factory::ToBoolean(bool value) {
   return value ? true_value() : false_value();
 }
 
 
 } }  // namespace v8::internal