Tentative implementation of string slices (hidden under the flag --string-slices).

src/heap-inl.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 300 matching lines @@
   // object->IsHeapNumber() and object->IsSeqString() because we already
   // know that object has the heap object tag.
 
   // These objects are never allocated in new space.
   ASSERT(type != MAP_TYPE);
   ASSERT(type != CODE_TYPE);
   ASSERT(type != ODDBALL_TYPE);
   ASSERT(type != JS_GLOBAL_PROPERTY_CELL_TYPE);
 
   if (type < FIRST_NONSTRING_TYPE) {
-    // There are three string representations: sequential strings, cons
-    // strings, and external strings.  Only cons strings contain
-    // non-map-word pointers to heap objects.
-    return ((type & kStringRepresentationMask) == kConsStringTag)
+    // There are four string representations: sequential strings, external
+    // strings, cons strings, and sliced strings.
+    // Only the latter two contain non-map-word pointers to heap objects.
+    return ((type & kIsIndirectStringMask) == kIsIndirectStringTag)
         ? OLD_POINTER_SPACE
         : OLD_DATA_SPACE;
   } else {
     return (type <= LAST_DATA_TYPE) ? OLD_DATA_SPACE : OLD_POINTER_SPACE;
   }
 }
 
 
 void Heap::CopyBlock(Address dst, Address src, int byte_size) {
   ASSERT(IsAligned(byte_size, kPointerSize));
@@ skipping 353 matching lines @@
 #ifdef DEBUG
   UpdateLiveObjectCount(obj);
 #endif
   obj->SetMark();
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_INL_H_