Two-threaded parser

src/parser.h

Index: src/parser.h
diff --git a/src/parser.h b/src/parser.h
index 216ee66e2985dddbd4346d9e3b2831fd48bbab6c..b04be1aa863fdcf3ab62ce6b07ff04dd5db0548e 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -790,13 +790,19 @@ class Parser : public ParserBase<ParserTraits> {
 
   Handle<String> LookupCachedSymbol(int symbol_id);
 
-  // Skip over a lazy function, either using cached data if we have it, or
-  // by parsing the function with PreParser. Consumes the ending }.
+  // Skip over a lazy function, either using cached data if we have it, or by
+  // parsing the function with PreParser. After returning, the position is just
+  // before the ending }.
   void SkipLazyFunctionBody(Handle<String> function_name,
+                            int function_block_pos,
                             int* materialized_literal_count,
                             int* expected_property_count,
+                            StrictMode* strict_mode,
                             bool* ok);
 
+  void ProcessErrorFromRecorder(PreParser::PreParseResult result,
+                                const SingletonLogger* logger, bool* ok);
+
   PreParser::PreParseResult ParseLazyFunctionBodyWithPreParser(
       SingletonLogger* logger);
 
@@ -808,6 +814,17 @@ class Parser : public ParserBase<ParserTraits> {
                                                bool is_generator,
                                                bool* ok);
 
+  // If possible, starts a background task for doing a fast pass over the script
+  // to find lazy functions with PreParser. Restrictions: 1) PreParser cannot
+  // yet parse everything that Parser can (e.g., harmony modules). So here we
+  // are on the safe side, and only use the FastParserThread when we're sure
+  // that the script is good (i.e., for scripts for which we produce cached
+  // data). TODO(marja): Use background tasks for other kinds of compilations
+  // too. 2) The thread cannot use the Isolate, or Handles, so this will only
+  // work if the actual data is kept outside the V8 heap as an external string.
+  void StartFastParserTaskIfPossible(Handle<String> source);
+  void FinishFastParserTask();
+
   Isolate* isolate_;
   ZoneList<Handle<String> > symbol_cache_;