Remove unused code, improve speed of Parser::CurrentToken (improvement seen in measurements and pro…

runtime/vm/parser.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_PARSER_H_
 #define VM_PARSER_H_
 
 #include "include/dart_api.h"
 
 #include "platform/assert.h"
@@ skipping 222 matching lines @@
   bool is_part_source() const {
     return script_.kind() == RawScript::kSourceTag;
   }
 
   // Parsing library patch script.
   bool is_patch_source() const {
     return script_.kind() == RawScript::kPatchTag;
   }
 
   intptr_t TokenPos() const { return tokens_iterator_.CurrentPosition(); }
-  inline Token::Kind CurrentToken();
+
+  Token::Kind CurrentToken() {

[hausner, 2014/05/27 21:03:29]

The performance now depends even more on the whim of the compiler's inlining
magic. In most cases, we only call CurrentToken() once to determine what we are
parsing. In cases where the parser calls it repetitively without advancing, we
should cache it locally. Eg. in ParseStatement() or ParsePrimary().

+    if (token_kind_ == Token::kILLEGAL) {
+      ComputeCurrentToken();
+    }
+    CompilerStats::num_token_checks++;
+    return token_kind_;
+  }
+
+  void ComputeCurrentToken();
+
   Token::Kind LookaheadToken(int num_tokens);
   String* CurrentLiteral() const;
   RawDouble* CurrentDoubleLiteral() const;
   RawInteger* CurrentIntegerLiteral() const;
 
   // Sets parser to given token position in the stream.
   void SetPosition(intptr_t position);
 
   void ConsumeToken() {
     // Reset cache and advance the token.
@@ skipping 466 matching lines @@
   intptr_t last_used_try_index_;
 
   bool unregister_pending_function_;
 
   DISALLOW_COPY_AND_ASSIGN(Parser);
 };
 
 }  // namespace dart
 
 #endif  // VM_PARSER_H_