Proof of concept: API for doing only one parsing pass instead of first preparsing and then parsing.

src/parser.h

 // Copyright 2012 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 591 matching lines @@
   Isolate* isolate() { return isolate_; }
   CompilationInfo* info() const { return info_; }
 
   // Called by ParseProgram after setting up the scanner.
   FunctionLiteral* DoParseProgram(CompilationInfo* info,
                                   Handle<String> source);
 
   // Report syntax error
   void ReportInvalidPreparseData(Handle<String> name, bool* ok);
 
-  void set_pre_parse_data(ScriptDataImpl *data) {
-    pre_parse_data_ = data;
-    symbol_cache_.Initialize(data ? data->symbol_count() : 0, zone());
+  void set_cached_data(ScriptDataImpl** data) {
+    cached_data_ = data;
+    symbol_cache_.Initialize(data && *data ? (*data)->symbol_count() : 0,
+                             zone());
   }
 
   bool inside_with() const { return scope_->inside_with(); }
   Mode mode() const { return mode_; }
-  ScriptDataImpl* pre_parse_data() const { return pre_parse_data_; }
   Scope* DeclarationScope(VariableMode mode) {
     return IsLexicalVariableMode(mode)
         ? scope_ : scope_->DeclarationScope();
   }
 
   // All ParseXXX functions take as the last argument an *ok parameter
   // which is set to false if parsing failed; it is unchanged otherwise.
   // By making the 'exception handling' explicit, we are forced to check
   // for failure at the call sites.
   void* ParseSourceElements(ZoneList<Statement*>* processor, int end_token,
@@ skipping 151 matching lines @@
 
   Isolate* isolate_;
   ZoneList<Handle<String> > symbol_cache_;
 
   Handle<Script> script_;
   Scanner scanner_;
   PreParser* reusable_preparser_;
   Scope* original_scope_;  // for ES5 function declarations in sloppy eval
   Target* target_stack_;  // for break, continue statements
   ScriptDataImpl* pre_parse_data_;
+  ScriptDataImpl** cached_data_;
 
   Mode mode_;
 
   CompilationInfo* info_;
 };
 
 
 // Support for handling complex values (array and object literals) that
 // can be fully handled at compile time.
 class CompileTimeValue: public AllStatic {
@@ skipping 18 matching lines @@
  private:
   static const int kLiteralTypeSlot = 0;
   static const int kElementsSlot = 1;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(CompileTimeValue);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_PARSER_H_