[parser] Refactor bookmark in SkipLazyFunctionBody

src/parsing/parser.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_PARSER_H_
 #define V8_PARSING_PARSER_H_
 
 #include "src/ast/ast.h"
 #include "src/ast/scopes.h"
 #include "src/parsing/parser-base.h"
@@ skipping 526 matching lines @@
   Statement* BuildAssertIsCoercible(Variable* var);
 
   // Factory methods.
   FunctionLiteral* DefaultConstructor(const AstRawString* name, bool call_super,
                                       int pos, int end_pos,
                                       LanguageMode language_mode);
 
   // Skip over a lazy function, either using cached data if we have it, or
   // by parsing the function with PreParser. Consumes the ending }.
   //
-  // If bookmark is set, the (pre-)parser may decide to abort skipping
+  // If may_abort == true, the (pre-)parser may decide to abort skipping
   // in order to force the function to be eagerly parsed, after all.

[adamk, 2016/08/30 22:13:14]

Mention when it'll return true vs false? I was surprised to see that "true"
means aborted and "false" means "not aborted".

Having read through the code I'm wondering if we'd be better off with an enum
(or maybe a pair of enums) here. It's a bit strange to see the unusual case as
"true".

[nickie, 2016/08/31 13:23:36]

Done.

-  // In this case, it'll reset the scanner using the bookmark.
-  void SkipLazyFunctionBody(int* materialized_literal_count,
-                            int* expected_property_count, bool* ok,
-                            Scanner::BookmarkScope* bookmark = nullptr);
+  bool SkipLazyFunctionBody(int* materialized_literal_count,
+                            int* expected_property_count, bool may_abort,
+                            bool* ok);
 
   PreParser::PreParseResult ParseLazyFunctionBodyWithPreParser(
-      SingletonLogger* logger, Scanner::BookmarkScope* bookmark = nullptr);
+      SingletonLogger* logger, bool may_abort);
 
   Block* BuildParameterInitializationBlock(
       const ParserFormalParameters& parameters, bool* ok);
   Block* BuildRejectPromiseOnException(Block* block, bool* ok);
 
   // Consumes the ending }.
   ZoneList<Statement*>* ParseEagerFunctionBody(
       const AstRawString* function_name, int pos,
       const ParserFormalParameters& parameters, FunctionKind kind,
       FunctionLiteral::FunctionType function_type, bool* ok);
@@ skipping 305 matching lines @@
   V8_INLINE static Literal* EmptyLiteral() { return nullptr; }
   V8_INLINE static ObjectLiteralProperty* EmptyObjectLiteralProperty() {
     return nullptr;
   }
   V8_INLINE static FunctionLiteral* EmptyFunctionLiteral() { return nullptr; }
 
   // Used in error return values.
   V8_INLINE static ZoneList<Expression*>* NullExpressionList() {
     return nullptr;
   }
+  V8_INLINE static ZoneList<Statement*>* NullStatementList() {
+    return nullptr;
+  }
 
   // Non-NULL empty string.
   V8_INLINE const AstRawString* EmptyIdentifierString() const {
     return ast_value_factory()->empty_string();
   }
 
   // Odd-ball literal creators.
   V8_INLINE Literal* GetLiteralTheHole(int position) {
     return factory()->NewTheHoleLiteral(kNoSourcePosition);
   }
@@ skipping 188 matching lines @@
   static const int kLiteralTypeSlot = 0;
   static const int kElementsSlot = 1;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(CompileTimeValue);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PARSING_PARSER_H_