Fix warnings on Win64.

src/objects-inl.h

 // Copyright 2006-2008 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 837 matching lines @@
   // Assert that the space encoding fits in the three bytes allotted for it.
   ASSERT((LAST_SPACE & ~kSpaceTagMask) == 0);
   intptr_t requested = requested_bytes >> kObjectAlignmentBits;
   int tag_bits = kSpaceTagSize + kFailureTypeTagSize;
   if (((requested << tag_bits) >> tag_bits) != requested) {
     // No room for entire requested size in the bits. Round down to
     // maximally representable size.
     requested = static_cast<intptr_t>(
                     (~static_cast<uintptr_t>(0)) >> (tag_bits + 1));
   }
-  int value = (requested << kSpaceTagSize) | NEW_SPACE;
+  int value = static_cast<int>(requested << kSpaceTagSize) | NEW_SPACE;
   return Construct(RETRY_AFTER_GC, value);
 }
 
 
 Failure* Failure::Construct(Type type, intptr_t value) {
   intptr_t info = (static_cast<intptr_t>(value) << kFailureTypeTagSize) | type;
   ASSERT(((info << kFailureTagSize) >> kFailureTagSize) == info);
   return reinterpret_cast<Failure*>((info << kFailureTagSize) | kFailureTag);
 }
 
@@ skipping 133 matching lines @@
       ((value_ & kMapPageOffsetMask) >> kMapPageOffsetShift)
       << kObjectAlignmentBits);
 
   return (map_space->PageAddress(map_page_index) + map_page_offset);
 }
 
 
 int MapWord::DecodeOffset() {
   // The offset field is represented in the kForwardingOffsetBits
   // most-significant bits.
-  int offset = (value_ >> kForwardingOffsetShift) << kObjectAlignmentBits;
-  ASSERT(0 <= offset && offset < Page::kObjectAreaSize);
-  return offset;
+  uintptr_t offset = (value_ >> kForwardingOffsetShift) << kObjectAlignmentBits;
+  ASSERT(offset < static_cast<uintptr_t>(Page::kObjectAreaSize));
+  return static_cast<int>(offset);
 }
 
 
 MapWord MapWord::FromEncodedAddress(Address address) {
   return MapWord(reinterpret_cast<uintptr_t>(address));
 }
 
 
 Address MapWord::ToEncodedAddress() {
   return reinterpret_cast<Address>(value_);
@@ skipping 2077 matching lines @@
 #undef WRITE_INT_FIELD
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_