Add dynamic stack frame alignment to optimized functions with untagged doubles on the stack.

src/heap.h

 // Copyright 2011 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 47 matching lines @@
   V(Map, one_pointer_filler_map, OnePointerFillerMap)                          \
   V(Map, two_pointer_filler_map, TwoPointerFillerMap)                          \
   /* Cluster the most popular ones in a few cache lines here at the top.    */ \
   V(Smi, store_buffer_top, StoreBufferTop)                                     \
   V(Object, undefined_value, UndefinedValue)                                   \
   V(Object, the_hole_value, TheHoleValue)                                      \
   V(Object, null_value, NullValue)                                             \
   V(Object, true_value, TrueValue)                                             \
   V(Object, false_value, FalseValue)                                           \
   V(Object, arguments_marker, ArgumentsMarker)                                 \
+  V(Object, frame_alignment_marker, FrameAlignmentMarker)                      \
   V(Map, heap_number_map, HeapNumberMap)                                       \
   V(Map, global_context_map, GlobalContextMap)                                 \
   V(Map, fixed_array_map, FixedArrayMap)                                       \
   V(Map, serialized_scope_info_map, SerializedScopeInfoMap)                    \
   V(Map, fixed_cow_array_map, FixedCOWArrayMap)                                \
   V(Map, fixed_double_array_map, FixedDoubleArrayMap)                          \
   V(Object, no_interceptor_result_sentinel, NoInterceptorResultSentinel)       \
   V(Map, meta_map, MetaMap)                                                    \
   V(Map, hash_table_map, HashTableMap)                                         \
   V(Smi, stack_limit, StackLimit)                                              \
@@ skipping 2399 matching lines @@
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG || LIVE_OBJECT_LIST
 
 } }  // namespace v8::internal
 
 #undef HEAP
 
 #endif  // V8_HEAP_H_