Experimental parser: set start_ properly after illegal token.

tools/lexer_generator/code_generator.jinja

 // Copyright 2013 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 155 matching lines @@
     {%- if start_node_number == node_number -%}
       code_start:
     {%- else -%}
       code_{{node_number}}:
     {%- endif -%}
   {%- else -%}
     // inlined state {{node_number}}
   {%- endif %}
 
   {% if debug_print %}
-    fprintf(stderr, "state {{state.node_number}}\n");
+    fprintf(stderr, "state {{state.node_number}}, start %d, cursor %d\n", start_ - buffer_, cursor_ - buffer_);
   {% endif -%}
 
   {%- set entry_action = state.entry_action -%}
   {%- if entry_action %}
     {{ dispatch_action(entry_action[0], entry_action[1]) }}
   {%- endif %}
 
   {%- if state['has_goto_after_entry'] -%}
       code_after_entry_{{node_number}}:
   {%- endif %}
@@ skipping 68 matching lines @@
 #define DO_TOKEN(T) {                 \
   PREPARE_TOKEN();                    \
   next_.token = T;                    \
   return;                             \
 }
 
 #define DO_TOKEN_AND_GO_FORWARD(T) {  \
   PREPARE_TOKEN();                    \
   FORWARD();                          \
   next_.token = T;                    \
+  start_ = cursor_;                   \
   return;                             \
 }
 
 #define DO_EOS() {                    \
   cursor_ -= 1;                       \
   DO_TOKEN(Token::EOS);               \
 }
 
 #define DO_LINE_TERMINATOR(s) {            \
   start_ = cursor_;                        \
@@ skipping 45 matching lines @@
   FORWARD();
   goto code_start;
 
   fell_through:
   ((void(*)())0)(); // crash
   // force use of stored_token
   stored_token = Token::ILLEGAL;
 }
 } }