[es6] implement default/optional parameters (WIP / comments)

src/ast.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_AST_H_
 #define V8_AST_H_
 
 #include "src/v8.h"
 
 #include "src/assembler.h"
@@ skipping 1330 matching lines @@
   const AstRawString* AsRawPropertyName() {
     DCHECK(IsPropertyName());
     return value_->AsString();
   }
 
   bool ToBooleanIsTrue() const OVERRIDE { return value()->BooleanValue(); }
   bool ToBooleanIsFalse() const OVERRIDE { return !value()->BooleanValue(); }
 
   Handle<Object> value() const { return value_->value(); }
   const AstValue* raw_value() const { return value_; }
+  bool IsUndefined() const { return value_->IsUndefined(); }
 
   // Support for using Literal as a HashMap key. NOTE: Currently, this works
   // only for string and number literals!
   uint32_t Hash();
   static bool Match(void* literal1, void* literal2);
 
   static int num_ids() { return parent_num_ids() + 1; }
   TypeFeedbackId LiteralFeedbackId() const {
     return TypeFeedbackId(local_id(0));
   }
@@ skipping 1137 matching lines @@
     GETTER_ARITY,
     SETTER_ARITY
   };
 
   DECLARE_NODE_TYPE(FunctionLiteral)
 
   Handle<String> name() const { return raw_name_->string(); }
   const AstRawString* raw_name() const { return raw_name_; }
   Scope* scope() const { return scope_; }
   ZoneList<Statement*>* body() const { return body_; }
+  ZoneList<Expression*>* default_values() const { return default_values_; }

[arv (Not doing code reviews), 2015/04/10 15:08:48]

I'm not sure we want a parallel list for this. It might be tempting to do that
for now but eventually we need to move away from this and store BindingElements
(which may or may not have an initializer).

[caitp (gmail), 2015/04/10 15:28:00]

I agree with you, see other comment. It's a quick hack for now, since I'm not
sure how much code needs to be fixed that is just expecting VariableProxy
expressions

   void set_function_token_position(int pos) { function_token_position_ = pos; }
   int function_token_position() const { return function_token_position_; }
   int start_position() const;
   int end_position() const;
   int SourceSize() const { return end_position() - start_position(); }
   bool is_expression() const { return IsExpression::decode(bitfield_); }
   bool is_anonymous() const { return IsAnonymous::decode(bitfield_); }
   LanguageMode language_mode() const;
   bool uses_super_property() const;
 
@@ skipping 84 matching lines @@
   BailoutReason dont_optimize_reason() { return dont_optimize_reason_; }
   void set_dont_optimize_reason(BailoutReason reason) {
     dont_optimize_reason_ = reason;
   }
 
  protected:
   FunctionLiteral(Zone* zone, const AstRawString* name,
                   AstValueFactory* ast_value_factory, Scope* scope,
                   ZoneList<Statement*>* body, int materialized_literal_count,
                   int expected_property_count, int handler_count,
-                  int parameter_count, FunctionType function_type,
+                  int parameter_count, ZoneList<Expression*>* default_values,
+                  FunctionType function_type,
                   ParameterFlag has_duplicate_parameters,
                   IsFunctionFlag is_function,
                   IsParenthesizedFlag is_parenthesized, FunctionKind kind,
                   int position)
       : Expression(zone, position),
         raw_name_(name),
         scope_(scope),
         body_(body),
         raw_inferred_name_(ast_value_factory->empty_string()),
         ast_properties_(zone),
         dont_optimize_reason_(kNoReason),
         materialized_literal_count_(materialized_literal_count),
         expected_property_count_(expected_property_count),
         handler_count_(handler_count),
         parameter_count_(parameter_count),
+        default_values_(default_values),
         function_token_position_(RelocInfo::kNoPosition) {
     bitfield_ = IsExpression::encode(function_type != DECLARATION) |
                 IsAnonymous::encode(function_type == ANONYMOUS_EXPRESSION) |
                 Pretenure::encode(false) |
                 HasDuplicateParameters::encode(has_duplicate_parameters) |
                 IsFunction::encode(is_function) |
                 IsParenthesized::encode(is_parenthesized) |
                 FunctionKindBits::encode(kind);
     DCHECK(IsValidFunctionKind(kind));
   }
 
  private:
   const AstRawString* raw_name_;
   Handle<String> name_;
   Handle<SharedFunctionInfo> shared_info_;
   Scope* scope_;
   ZoneList<Statement*>* body_;
   const AstString* raw_inferred_name_;
   Handle<String> inferred_name_;
   AstProperties ast_properties_;
   BailoutReason dont_optimize_reason_;
 
   int materialized_literal_count_;
   int expected_property_count_;
   int handler_count_;
   int parameter_count_;
+  ZoneList<Expression*>* default_values_;
   int function_token_position_;
 
   unsigned bitfield_;
   class IsExpression : public BitField<bool, 0, 1> {};
   class IsAnonymous : public BitField<bool, 1, 1> {};
   class Pretenure : public BitField<bool, 2, 1> {};
   class HasDuplicateParameters : public BitField<ParameterFlag, 3, 1> {};
   class IsFunction : public BitField<IsFunctionFlag, 4, 1> {};
   class IsParenthesized : public BitField<IsParenthesizedFlag, 5, 1> {};
   class FunctionKindBits : public BitField<FunctionKind, 6, 8> {};
@@ skipping 868 matching lines @@
   }
 
   Throw* NewThrow(Expression* exception, int pos) {
     return new (zone_) Throw(zone_, exception, pos);
   }
 
   FunctionLiteral* NewFunctionLiteral(
       const AstRawString* name, AstValueFactory* ast_value_factory,
       Scope* scope, ZoneList<Statement*>* body, int materialized_literal_count,
       int expected_property_count, int handler_count, int parameter_count,
+      ZoneList<Expression*>* default_parameters,
       FunctionLiteral::ParameterFlag has_duplicate_parameters,
       FunctionLiteral::FunctionType function_type,
       FunctionLiteral::IsFunctionFlag is_function,
       FunctionLiteral::IsParenthesizedFlag is_parenthesized, FunctionKind kind,
       int position) {
     return new (zone_) FunctionLiteral(
         zone_, name, ast_value_factory, scope, body, materialized_literal_count,
-        expected_property_count, handler_count, parameter_count, function_type,
-        has_duplicate_parameters, is_function, is_parenthesized, kind,
-        position);
+        expected_property_count, handler_count, parameter_count,
+        default_parameters, function_type, has_duplicate_parameters,
+        is_function, is_parenthesized, kind, position);
   }
 
   ClassLiteral* NewClassLiteral(const AstRawString* name, Scope* scope,
                                 VariableProxy* proxy, Expression* extends,
                                 FunctionLiteral* constructor,
                                 ZoneList<ObjectLiteral::Property*>* properties,
                                 int start_position, int end_position) {
     return new (zone_)
         ClassLiteral(zone_, name, scope, proxy, extends, constructor,
                      properties, start_position, end_position);
@@ skipping 15 matching lines @@
 
  private:
   Zone* zone_;
   AstValueFactory* ast_value_factory_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_