Introduce "optimized_out" oddball marker for compilers.

src/heap/heap.h

 // 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.
 
 #ifndef V8_HEAP_HEAP_H_
 #define V8_HEAP_HEAP_H_
 
 #include <cmath>
 #include <map>
 
@@ skipping 57 matching lines @@
   V(FixedArray, empty_fixed_array, EmptyFixedArray)                            \
   V(ByteArray, empty_byte_array, EmptyByteArray)                               \
   V(DescriptorArray, empty_descriptor_array, EmptyDescriptorArray)             \
   /* The roots above this line should be boring from a GC point of view.    */ \
   /* This means they are never in new space and never on a page that is     */ \
   /* being compacted.                                                       */ \
   V(Oddball, no_interceptor_result_sentinel, NoInterceptorResultSentinel)      \
   V(Oddball, arguments_marker, ArgumentsMarker)                                \
   V(Oddball, exception, Exception)                                             \
   V(Oddball, termination_exception, TerminationException)                      \
+  V(Oddball, optimized_out, OptimizedOut)                                      \
   V(FixedArray, number_string_cache, NumberStringCache)                        \
   V(Object, instanceof_cache_function, InstanceofCacheFunction)                \
   V(Object, instanceof_cache_map, InstanceofCacheMap)                          \
   V(Object, instanceof_cache_answer, InstanceofCacheAnswer)                    \
   V(FixedArray, single_character_string_cache, SingleCharacterStringCache)     \
   V(FixedArray, string_split_cache, StringSplitCache)                          \
   V(FixedArray, regexp_multiple_cache, RegExpMultipleCache)                    \
   V(Smi, hash_seed, HashSeed)                                                  \
   V(Map, hash_table_map, HashTableMap)                                         \
   V(Map, ordered_hash_table_map, OrderedHashTableMap)                          \
@@ skipping 52 matching lines @@
   V(Map, script_context_table_map, ScriptContextTableMap)                      \
   V(Map, undefined_map, UndefinedMap)                                          \
   V(Map, the_hole_map, TheHoleMap)                                             \
   V(Map, null_map, NullMap)                                                    \
   V(Map, boolean_map, BooleanMap)                                              \
   V(Map, uninitialized_map, UninitializedMap)                                  \
   V(Map, arguments_marker_map, ArgumentsMarkerMap)                             \
   V(Map, no_interceptor_result_sentinel_map, NoInterceptorResultSentinelMap)   \
   V(Map, exception_map, ExceptionMap)                                          \
   V(Map, termination_exception_map, TerminationExceptionMap)                   \
+  V(Map, optimized_out_map, OptimizedOutMap)                                   \
   V(Map, message_object_map, JSMessageObjectMap)                               \
   V(Map, foreign_map, ForeignMap)                                              \
   V(Map, neander_map, NeanderMap)                                              \
   V(Map, external_map, ExternalMap)                                            \
   V(HeapNumber, nan_value, NanValue)                                           \
   V(HeapNumber, infinity_value, InfinityValue)                                 \
   V(HeapNumber, minus_zero_value, MinusZeroValue)                              \
   V(HeapNumber, minus_infinity_value, MinusInfinityValue)                      \
   V(JSObject, message_listeners, MessageListeners)                             \
   V(UnseededNumberDictionary, code_stubs, CodeStubs)                           \
@@ skipping 2472 matching lines @@
   friend class LargeObjectSpace;
   friend class NewSpace;
   friend class PagedSpace;
   DISALLOW_COPY_AND_ASSIGN(AllocationObserver);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_HEAP_H_