Add explicit integer type-casts to make WIN64 build without errors.

src/objects.h

 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2617 matching lines @@
     ASSERT_SIZE_TAG_ALIGNED(body_size);
     ASSERT_SIZE_TAG_ALIGNED(sinfo_size);
     return RoundUp(kHeaderSize + body_size + sinfo_size, kCodeAlignment);
   }
 
   // Calculate the size of the code object to report for log events. This takes
   // the layout of the code object into account.
   int ExecutableSize() {
     // Check that the assumptions about the layout of the code object holds.
     ASSERT_EQ(instruction_start() - address(),
-              Code::kHeaderSize);
+              static_cast<intptr_t>(Code::kHeaderSize));
     return instruction_size() + Code::kHeaderSize;
   }
 
   // Locating source position.
   int SourcePosition(Address pc);
   int SourceStatementPosition(Address pc);
 
   // Casting.
   static inline Code* cast(Object* obj);
 
@@ skipping 2204 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_