[esnext] implement frontend changes for async/await proposal

src/ast/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_AST_H_
 #define V8_AST_AST_H_
 
 #include "src/assembler.h"
 #include "src/ast/ast-value-factory.h"
 #include "src/ast/modules.h"
@@ skipping 374 matching lines @@
     DCHECK(!BailoutId(base_id_).IsNone());
     return base_id_;
   }
 
  private:
   int local_id(int n) const { return base_id() + parent_num_ids() + n; }
 
   int base_id_;
   Bounds bounds_;
   class ToBooleanTypesField : public BitField16<uint16_t, 0, 9> {};
+
+ protected:
+  static const int kExpressionBitFieldNext = ToBooleanTypesField::kNext;
   uint16_t bit_field_;
   // Ends with 16-bit field; deriving classes in turn begin with
   // 16-bit fields for optimum packing efficiency.
 };
 
 
 class BreakableStatement : public Statement {
  public:
   enum BreakableType {
     TARGET_FOR_ANONYMOUS,
@@ skipping 2177 matching lines @@
   Handle<String> name() const { return raw_name_->string(); }
   const AstString* raw_name() const { return raw_name_; }
   void set_raw_name(const AstString* name) { raw_name_ = name; }
   Scope* scope() const { return scope_; }
   ZoneList<Statement*>* body() const { return body_; }
   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_declaration() const { return IsDeclaration::decode(bitfield_); }
+  bool is_declaration() const {
+    return IsDeclaration::decode(Expression::bit_field_);
+  }
   bool is_named_expression() const {
     return IsNamedExpression::decode(bitfield_);
   }
   bool is_anonymous_expression() const {
     return IsAnonymousExpression::decode(bitfield_);
   }
   LanguageMode language_mode() const;
 
   static bool NeedsHomeObject(Expression* expr);
 
@@ skipping 106 matching lines @@
         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),
         parameter_count_(parameter_count),
         function_token_position_(RelocInfo::kNoPosition),
         yield_count_(0) {
     bitfield_ =
-        IsDeclaration::encode(function_type == kDeclaration) |
         IsNamedExpression::encode(function_type == kNamedExpression) |
         IsAnonymousExpression::encode(function_type == kAnonymousExpression) |
         Pretenure::encode(false) |
         HasDuplicateParameters::encode(has_duplicate_parameters ==
                                        kHasDuplicateParameters) |
         IsFunction::encode(is_function) |
         ShouldEagerCompile::encode(eager_compile_hint == kShouldEagerCompile) |
         FunctionKindBits::encode(kind) | ShouldBeUsedOnceHint::encode(false);
     DCHECK(IsValidFunctionKind(kind));
   }
 
  private:
-  class IsDeclaration : public BitField16<bool, 0, 1> {};
-  class IsNamedExpression : public BitField16<bool, 1, 1> {};
-  class IsAnonymousExpression : public BitField16<bool, 2, 1> {};
-  class Pretenure : public BitField16<bool, 3, 1> {};
-  class HasDuplicateParameters : public BitField16<bool, 4, 1> {};
-  class IsFunction : public BitField16<bool, 5, 1> {};
-  class ShouldEagerCompile : public BitField16<bool, 6, 1> {};
-  class ShouldBeUsedOnceHint : public BitField16<bool, 7, 1> {};
-  class FunctionKindBits : public BitField16<FunctionKind, 8, 8> {};
+  STATIC_ASSERT((Expression::kExpressionBitFieldNext + 1) < 16);
+  class IsDeclaration
+      : public BitField16<bool, Expression::kExpressionBitFieldNext, 1> {};
+  class IsNamedExpression : public BitField16<bool, 0, 1> {};
+  class IsAnonymousExpression : public BitField16<bool, 1, 1> {};
+  class Pretenure : public BitField16<bool, 2, 1> {};
+  class HasDuplicateParameters : public BitField16<bool, 3, 1> {};
+  class IsFunction : public BitField16<bool, 4, 1> {};
+  class ShouldEagerCompile : public BitField16<bool, 5, 1> {};
+  class ShouldBeUsedOnceHint : public BitField16<bool, 6, 1> {};
+  class FunctionKindBits : public BitField16<FunctionKind, 7, 9> {};
 
   // Start with 16-bit field, which should get packed together
   // with Expression's trailing 16-bit field.
   uint16_t bitfield_;
 
   const AstString* raw_name_;
   Scope* scope_;
   ZoneList<Statement*>* body_;
   const AstString* raw_inferred_name_;
   Handle<String> inferred_name_;
@@ skipping 797 matching lines @@
                                     : NULL;                                   \
   }
 AST_NODE_LIST(DECLARE_NODE_FUNCTIONS)
 #undef DECLARE_NODE_FUNCTIONS
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_AST_AST_H_