Mark maps having a hidden prototype rather than maps of hidden prototypes.

src/mips/builtins-mips.cc

 // Copyright 2012 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_MIPS
 
 #include "src/codegen.h"
 #include "src/debug/debug.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 1450 matching lines @@
   __ GetObjectType(type, scratch, scratch);
   __ Branch(&next_prototype, ne, scratch, Operand(FUNCTION_TEMPLATE_INFO_TYPE));
 
   // Otherwise load the parent function template and iterate.
   __ lw(type,
         FieldMemOperand(type, FunctionTemplateInfo::kParentTemplateOffset));
   __ Branch(&function_template_loop);
 
   // Load the next prototype and iterate.
   __ bind(&next_prototype);
+  __ lw(scratch, FieldMemOperand(map, Map::kBitField3Offset));
+  __ DecodeField<Map::HasHiddenPrototype>(scratch);
+  __ Branch(receiver_check_failed, eq, scratch, Operand(zero_reg));
   __ lw(receiver, FieldMemOperand(map, Map::kPrototypeOffset));
-  // End if the prototype is null or not hidden.
-  __ JumpIfRoot(receiver, Heap::kNullValueRootIndex, receiver_check_failed);
   __ lw(map, FieldMemOperand(receiver, HeapObject::kMapOffset));
-  __ lw(scratch, FieldMemOperand(map, Map::kBitField3Offset));
-  __ DecodeField<Map::IsHiddenPrototype>(scratch);
-  __ Branch(receiver_check_failed, eq, scratch, Operand(zero_reg));
 
   __ Branch(&prototype_loop_start);
 
   __ bind(&receiver_check_passed);
 }
 
 
 void Builtins::Generate_HandleFastApiCall(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- a0                 : number of arguments excluding receiver
@@ skipping 1274 matching lines @@
   }
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS