Introduce "optimized_out" oddball marker for compilers.

src/types.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.
 
 #include <iomanip>
 
 #include "src/types.h"
 
 #include "src/handles-inl.h"
 #include "src/ostreams.h"
@@ skipping 173 matching lines @@
       return kSymbol;
     case ODDBALL_TYPE: {
       Heap* heap = map->GetHeap();
       if (map == heap->undefined_map()) return kUndefined;
       if (map == heap->null_map()) return kNull;
       if (map == heap->boolean_map()) return kBoolean;
       DCHECK(map == heap->the_hole_map() ||
              map == heap->uninitialized_map() ||
              map == heap->no_interceptor_result_sentinel_map() ||
              map == heap->termination_exception_map() ||
-             map == heap->arguments_marker_map());
+             map == heap->arguments_marker_map() ||
+             map == heap->optimized_out_map());
       return kInternal & kTaggedPointer;
     }
     case HEAP_NUMBER_TYPE:
       return kNumber & kTaggedPointer;
     case SIMD128_VALUE_TYPE:
       return kSimd;
     case JS_OBJECT_TYPE:
     case JS_GLOBAL_OBJECT_TYPE:
     case JS_GLOBAL_PROXY_TYPE:
     case JS_SPECIAL_API_OBJECT_TYPE:
@@ skipping 1062 matching lines @@
 #undef CONSTRUCT_SIMD_TYPE
 
 // -----------------------------------------------------------------------------
 // Instantiations.
 
 template class Type::Iterator<i::Map>;
 template class Type::Iterator<i::Object>;
 
 }  // namespace internal
 }  // namespace v8