Avoid (some) symbol lookups at parse time if preparse data is available.

src/v8-counters.h

 // Copyright 2007-2008 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 80 matching lines @@
   SC(string_ctor_string_value, V8.StringConstructorStringValue)       \
   SC(string_ctor_gc_required, V8.StringConstructorGCRequired)         \
   /* Amount of evaled source code. */                                 \
   SC(total_eval_size, V8.TotalEvalSize)                               \
   /* Amount of loaded source code. */                                 \
   SC(total_load_size, V8.TotalLoadSize)                               \
   /* Amount of parsed source code. */                                 \
   SC(total_parse_size, V8.TotalParseSize)                             \
   /* Amount of source code skipped over using preparsing. */          \
   SC(total_preparse_skipped, V8.TotalPreparseSkipped)                 \
+  /* Number of symbol lookups skipped using preparsing */             \
+  SC(total_preparse_symbols_skipped, V8.TotalPreparseSymbolSkipped)   \
   /* Amount of compiled source code. */                               \
   SC(total_compile_size, V8.TotalCompileSize)                         \
   /* Amount of source code compiled with the old codegen. */          \
   SC(total_old_codegen_source_size, V8.TotalOldCodegenSourceSize)     \
   /* Amount of source code compiled with the full codegen. */         \
   SC(total_full_codegen_source_size, V8.TotalFullCodegenSourceSize)   \
   /* Number of contexts created from scratch. */                      \
   SC(contexts_created_from_scratch, V8.ContextsCreatedFromScratch)    \
   /* Number of contexts created by partial snapshot. */               \
   SC(contexts_created_by_snapshot, V8.ContextsCreatedBySnapshot)      \
@@ skipping 145 matching lines @@
     stats_counter_count
   };
 
   // Sliding state window counters.
   static StatsCounter state_counters[];
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_V8_COUNTERS_H_