Reland "In-object double fields unboxing (for 64-bit only)."

src/string-stream.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 "src/string-stream.h"
 
 #include "src/handles-inl.h"
 #include "src/prototype.h"
 
 namespace v8 {
@@ skipping 333 matching lines @@
         }
         for (; len < 18; len++)
           Put(' ');
         if (key->IsString()) {
           Put(String::cast(key));
         } else {
           key->ShortPrint();
         }
         Add(": ");
         FieldIndex index = FieldIndex::ForDescriptor(map, i);
-        Object* value = js_object->RawFastPropertyAt(index);
-        Add("%o\n", value);
+        if (js_object->IsUnboxedDoubleField(index)) {
+          double value = js_object->RawFastDoublePropertyAt(index);
+          Add("<unboxed double> %.16g\n", FmtElm(value));
+        } else {
+          Object* value = js_object->RawFastPropertyAt(index);
+          Add("%o\n", value);
+        }
       }
     }
   }
 }
 
 
 void StringStream::PrintFixedArray(FixedArray* array, unsigned int limit) {
   Heap* heap = array->GetHeap();
   for (unsigned int i = 0; i < 10 && i < limit; i++) {
     Object* element = array->get(i);
@@ skipping 185 matching lines @@
   }
   MemCopy(new_space, space_, *bytes);
   *bytes = new_bytes;
   DeleteArray(space_);
   space_ = new_space;
   return new_space;
 }
 
 
 } }  // namespace v8::internal