Follow-up to r19845 which suppresses syntax errors in presence of a stack overflow.

src/preparser.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 998 matching lines @@
 template<class Traits>
 ParserBase<Traits>::FunctionState::~FunctionState() {
   *scope_stack_ = outer_scope_;
   *function_state_stack_ = outer_function_state_;
   Traits::TearDownFunctionState(this);
 }
 
 
 template<class Traits>
 void ParserBase<Traits>::ReportUnexpectedToken(Token::Value token) {
-  // We don't report stack overflows here, to avoid increasing the
-  // stack depth even further.  Instead we report it after parsing is
-  // over, in ParseProgram.
-  if (token == Token::ILLEGAL && stack_overflow()) {
+  if (stack_overflow()) {

[Michael Starzinger, 2014/03/12 13:45:08]

All cases below call through to ReportMessageAt, which already should have the
special handling for stack overflows. Could we completely drop this check here?
Or am I missing something?

[marja, 2014/03/12 13:50:40]

Done; updated description to explain in detail why this is correct.

+    // Suppress the error message in the presence of a stack overflow. The
+    // isolate allows only one pending exception at at time and we want to
+    // report the stack overflow later.
     return;
   }
   Scanner::Location source_location = scanner()->location();
 
   // Four of the tokens are treated specially
   switch (token) {
     case Token::EOS:
       return ReportMessageAt(source_location, "unexpected_eos");
     case Token::NUMBER:
       return ReportMessageAt(source_location, "unexpected_token_number");
@@ skipping 508 matching lines @@
                                "accessor_get_set");
     }
     *ok = false;
   }
 }
 
 
 } }  // v8::internal
 
 #endif  // V8_PREPARSER_H