Move function length tracking from Scope to (Pre)?ParserFormalParameters.

src/parsing/preparser.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_PARSING_PREPARSER_H
 #define V8_PARSING_PREPARSER_H
 
 #include "src/ast/scopes.h"
 #include "src/parsing/parser-base.h"
 
@@ skipping 640 matching lines @@
                                  int pos) {
     return PreParserExpression::Default();
   }
   PreParserStatement NewReturnStatement(PreParserExpression expression,
                                         int pos) {
     return PreParserStatement::Jump();
   }
   PreParserExpression NewFunctionLiteral(
       PreParserIdentifier name, Scope* scope, PreParserStatementList body,
       int materialized_literal_count, int expected_property_count,
-      int parameter_count,
+      int parameter_count, int function_length,
       FunctionLiteral::ParameterFlag has_duplicate_parameters,
       FunctionLiteral::FunctionType function_type,
       FunctionLiteral::EagerCompileHint eager_compile_hint, int position) {
     return PreParserExpression::Default();
   }
 
   PreParserExpression NewSpread(PreParserExpression expression, int pos,
                                 int expr_pos) {
     return PreParserExpression::Spread(expression);
   }
@@ skipping 82 matching lines @@
   }
 
  private:
   Zone* zone_;
 };
 
 
 struct PreParserFormalParameters : FormalParametersBase {
   explicit PreParserFormalParameters(DeclarationScope* scope)
       : FormalParametersBase(scope) {}
-  int arity = 0;
-
-  int Arity() const { return arity; }
   PreParserIdentifier at(int i) { return PreParserIdentifier(); }  // Dummy
 };
 
 
 class PreParser;
 
 class PreParserTarget {
  public:
   PreParserTarget(ParserBase<PreParser>* preparser,
                   PreParserStatement statement) {}
@@ skipping 650 matching lines @@
 
   V8_INLINE void AddParameterInitializationBlock(
       const PreParserFormalParameters& parameters, PreParserStatementList body,
       bool is_async, bool* ok) {}
 
   V8_INLINE void AddFormalParameter(PreParserFormalParameters* parameters,
                                     PreParserExpression pattern,
                                     PreParserExpression initializer,
                                     int initializer_end_position,
                                     bool is_rest) {
-    ++parameters->arity;
+    parameters->UpdateArityAndFunctionLength(!initializer.IsEmpty(), is_rest);
   }
 
   V8_INLINE void DeclareFormalParameter(DeclarationScope* scope,
                                         PreParserIdentifier parameter) {
     if (!classifier()->is_simple_parameter_list()) {
       scope->SetHasNonSimpleParameters();
     }
   }
 
   V8_INLINE void DeclareArrowFunctionFormalParameters(
@@ skipping 93 matching lines @@
     function_state_->NextMaterializedLiteralIndex();
     function_state_->NextMaterializedLiteralIndex();
   }
   return EmptyExpression();
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PARSING_PREPARSER_H