[ic] Cache weak cells containing prototypes in respective PrototypeInfo objects.

src/ic/x64/handler-compiler-x64.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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/ic/handler-compiler.h"
 
 #include "src/api-arguments.h"
 #include "src/field-type.h"
@@ skipping 466 matching lines @@
       DCHECK(!current_map->IsJSGlobalProxyMap());  // Proxy maps are fast.
       if (!name->IsUniqueName()) {
         DCHECK(name->IsString());
         name = factory()->InternalizeString(Handle<String>::cast(name));
       }
       DCHECK(current.is_null() ||
              current->property_dictionary()->FindEntry(name) ==
                  NameDictionary::kNotFound);
 
       if (depth > 1) {
-        // TODO(jkummerow): Cache and re-use weak cell.
-        __ LoadWeakValue(reg, isolate()->factory()->NewWeakCell(current), miss);
+        Handle<WeakCell> weak_cell =
+            Map::GetOrCreatePrototypeWeakCell(current, isolate());
+        __ LoadWeakValue(reg, weak_cell, miss);
       }
       GenerateDictionaryNegativeLookup(masm(), miss, reg, name, scratch1,
                                        scratch2);
     }
 
     reg = holder_reg;  // From now on the object will be in holder_reg.
     // Go to the next object in the prototype chain.
     current = prototype;
     current_map = handle(current->map());
   }
 
   DCHECK(!current_map->IsJSGlobalProxyMap());
 
   // Log the check depth.
   LOG(isolate(), IntEvent("check-maps-depth", depth + 1));
 
   bool return_holder = return_what == RETURN_HOLDER;
   if (return_holder && depth != 0) {
-    __ LoadWeakValue(reg, isolate()->factory()->NewWeakCell(current), miss);
+    Handle<WeakCell> weak_cell =
+        Map::GetOrCreatePrototypeWeakCell(current, isolate());
+    __ LoadWeakValue(reg, weak_cell, miss);
   }
 
   // Return the register containing the holder.
   return return_holder ? reg : no_reg;
 }
 
 
 void NamedLoadHandlerCompiler::FrontendFooter(Handle<Name> name, Label* miss) {
   if (!miss->is_unused()) {
     Label success;
@@ skipping 174 matching lines @@
   // Return the generated code.
   return GetCode(kind(), name);
 }
 
 
 #undef __
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64