Use code_range()->exists() to determine the size of the first code page when code range is used.

src/spaces.cc

 // 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 1012 matching lines @@
     case OLD_DATA_SPACE:
       size = 192 * KB;
       break;
     case MAP_SPACE:
       size = 16 * kPointerSize * KB;
       break;
     case CELL_SPACE:
       size = 16 * kPointerSize * KB;
       break;
     case CODE_SPACE:
-      if (kPointerSize == 8) {
-        // On x64 we allocate code pages in a special way (from the reserved
-        // 2Byte area). That part of the code is not yet upgraded to handle
-        // small pages.
+      if (heap()->isolate()->code_range()->exists()) {
+        // When code range exists, code pages are allocated in a special way
+        // (from the reserved code range). That part of the code is not yet
+        // upgraded to handle small pages.
         size = AreaSize();
       } else {
         size = 384 * KB;
       }
       break;
     default:
       UNREACHABLE();
   }
   return Min(size, AreaSize());
 }
@@ skipping 2096 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 
 } }  // namespace v8::internal