Parser: store parameters in a ThreadedList instead of ZoneList.

src/parsing/preparser.cc

Index: src/parsing/preparser.cc
diff --git a/src/parsing/preparser.cc b/src/parsing/preparser.cc
index c7b2e1b5d25d6e9537e62989e4a610d6ee47ee68..804e5e1ae01a3203fa9b9b5e434091629f6dcfea 100644
--- a/src/parsing/preparser.cc
+++ b/src/parsing/preparser.cc
@@ -101,7 +101,8 @@ PreParser::PreParseResult PreParser::PreParseFunction(
   bool ok_holder = true;
   bool* ok = &ok_holder;
 
-  PreParserFormalParameters formals(function_scope);
+  PreParserFormalParameters* formals =
+      new (zone()) PreParserFormalParameters(function_scope);
   bool has_duplicate_parameters = false;
   DuplicateFinder duplicate_finder(scanner()->unicode_cache());
   std::unique_ptr<ExpressionClassifier> formals_classifier;
@@ -112,20 +113,21 @@ PreParser::PreParseResult PreParser::PreParseFunction(
     formals_classifier.reset(new ExpressionClassifier(this, &duplicate_finder));
     // We return kPreParseSuccess in failure cases too - errors are retrieved
     // separately by Parser::SkipLazyFunctionBody.
-    ParseFormalParameterList(&formals, CHECK_OK_VALUE(kPreParseSuccess));
+    ParseFormalParameterList(formals, CHECK_OK_VALUE(kPreParseSuccess));
     Expect(Token::RPAREN, CHECK_OK_VALUE(kPreParseSuccess));
     int formals_end_position = scanner()->location().end_pos;
 
-    CheckArityRestrictions(
-        formals.arity, kind, formals.has_rest, function_scope->start_position(),
-        formals_end_position, CHECK_OK_VALUE(kPreParseSuccess));
+    CheckArityRestrictions(formals->arity, kind, formals->has_rest,
+                           function_scope->start_position(),
+                           formals_end_position,
+                           CHECK_OK_VALUE(kPreParseSuccess));
     has_duplicate_parameters =
         !classifier()->is_valid_formal_parameter_list_without_duplicates();
   }
 
   Expect(Token::LBRACE, CHECK_OK_VALUE(kPreParseSuccess));
   LazyParsingResult result = ParseStatementListAndLogFunction(
-      &formals, has_duplicate_parameters, may_abort, ok);
+      formals, has_duplicate_parameters, may_abort, ok);
   use_counts_ = nullptr;
   track_unresolved_variables_ = false;
   if (result == kLazyParsingAborted) {
@@ -141,7 +143,7 @@ PreParser::PreParseResult PreParser::PreParseFunction(
       // Validate parameter names. We can do this only after parsing the
       // function, since the function can declare itself strict.
       const bool allow_duplicate_parameters =
-          is_sloppy(function_scope->language_mode()) && formals.is_simple &&
+          is_sloppy(function_scope->language_mode()) && formals->is_simple &&
           !IsConciseMethod(kind);
       ValidateFormalParameters(function_scope->language_mode(),
                                allow_duplicate_parameters,
@@ -199,13 +201,14 @@ PreParser::Expression PreParser::ParseFunctionLiteral(
   Expect(Token::LPAREN, CHECK_OK);
   int start_position = scanner()->location().beg_pos;
   function_scope->set_start_position(start_position);
-  PreParserFormalParameters formals(function_scope);
-  ParseFormalParameterList(&formals, CHECK_OK);
+  PreParserFormalParameters* formals =
+      new (zone()) PreParserFormalParameters(function_scope);
+  ParseFormalParameterList(formals, CHECK_OK);
   Expect(Token::RPAREN, CHECK_OK);
   int formals_end_position = scanner()->location().end_pos;
 
-  CheckArityRestrictions(formals.arity, kind, formals.has_rest, start_position,
-                         formals_end_position, CHECK_OK);
+  CheckArityRestrictions(formals->arity, kind, formals->has_rest,
+                         start_position, formals_end_position, CHECK_OK);
 
   Expect(Token::LBRACE, CHECK_OK);
   ParseStatementList(body, Token::RBRACE, CHECK_OK);
@@ -219,7 +222,7 @@ PreParser::Expression PreParser::ParseFunctionLiteral(
   CheckFunctionName(language_mode, function_name, function_name_validity,
                     function_name_location, CHECK_OK);
   const bool allow_duplicate_parameters =
-      is_sloppy(language_mode) && formals.is_simple && !IsConciseMethod(kind);
+      is_sloppy(language_mode) && formals->is_simple && !IsConciseMethod(kind);
   ValidateFormalParameters(language_mode, allow_duplicate_parameters, CHECK_OK);
 
   int end_position = scanner()->location().end_pos;