[esnext] implement frontend changes for async/await proposal

src/parsing/scanner.h

 // Copyright 2011 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.
 
 // Features shared by parsing and pre-parsing scanners.
 
 #ifndef V8_PARSING_SCANNER_H_
 #define V8_PARSING_SCANNER_H_
 
 #include "src/allocation.h"
@@ skipping 353 matching lines @@
   bool has_error() const { return scanner_error_ != MessageTemplate::kNone; }
   MessageTemplate::Template error() const { return scanner_error_; }
   Location error_location() const { return scanner_error_location_; }
 
   // Similar functions for the upcoming token.
 
   // One token look-ahead (past the token returned by Next()).
   Token::Value peek() const { return next_.token; }
 
   Location peek_location() const { return next_.location; }
+  Location peek_ahead_location() const {
+    DCHECK(next_next_.token != Token::UNINITIALIZED);
+    return next_next_.location;
+  }
 
   bool literal_contains_escapes() const {
     return LiteralContainsEscapes(current_);
   }
   bool next_literal_contains_escapes() const {
     return LiteralContainsEscapes(next_);
   }
   bool is_literal_contextual_keyword(Vector<const char> keyword) {
     DCHECK_NOT_NULL(current_.literal_chars);
     return current_.literal_chars->is_contextual_keyword(keyword);
   }
   bool is_next_contextual_keyword(Vector<const char> keyword) {
     DCHECK_NOT_NULL(next_.literal_chars);
     return next_.literal_chars->is_contextual_keyword(keyword);
   }
 
+  bool is_next_next_contextual_keyword(Vector<const char> keyword) {
+    DCHECK_NOT_NULL(next_next_.literal_chars);
+    return next_next_.literal_chars->is_contextual_keyword(keyword);
+  }
+
   const AstRawString* CurrentSymbol(AstValueFactory* ast_value_factory);
   const AstRawString* NextSymbol(AstValueFactory* ast_value_factory);
+  const AstRawString* NextNextSymbol(AstValueFactory* ast_value_factory);
   const AstRawString* CurrentRawSymbol(AstValueFactory* ast_value_factory);
 
   double DoubleValue();
   bool ContainsDot();
   bool LiteralMatches(const char* data, int length, bool allow_escapes = true) {
     if (is_literal_one_byte() &&
         literal_length() == length &&
         (allow_escapes || !literal_contains_escapes())) {
       const char* token =
           reinterpret_cast<const char*>(literal_one_byte_string().start());
@@ skipping 29 matching lines @@
 
   // Seek forward to the given position.  This operation does not
   // work in general, for instance when there are pushed back
   // characters, but works for seeking forward until simple delimiter
   // tokens, which is what it is used for.
   void SeekForward(int pos);
 
   // Returns true if there was a line terminator before the peek'ed token,
   // possibly inside a multi-line comment.
   bool HasAnyLineTerminatorBeforeNext() const {
-    return has_line_terminator_before_next_ ||
-           has_multiline_comment_before_next_;
+    return has_preceding_line_terminator_ || has_preceding_multiline_comment_;
+  }
+
+  bool HasAnyLineTerminatorAfterNext() {
+    Token::Value ensure_next_next = PeekAhead();
+    USE(ensure_next_next);
+    return next_has_preceding_line_terminator_;
   }
 
   // Scans the input as a regular expression pattern, previous
   // character(s) must be /(=). Returns true if a pattern is scanned.
   bool ScanRegExpPattern(bool seen_equal);
   // Scans the input as regular expression flags. Returns the flags on success.
   Maybe<RegExp::Flags> ScanRegExpFlags();
 
   // Scans the input as a template literal
   Token::Value ScanTemplateStart();
@@ skipping 320 matching lines @@
   Utf16CharacterStream* source_;
 
 
   // Start position of the octal literal last scanned.
   Location octal_pos_;
 
   // One Unicode character look-ahead; c0_ < 0 at the end of the input.
   uc32 c0_;
 
   // Whether there is a line terminator whitespace character after
-  // the current token, and  before the next. Does not count newlines
-  // inside multiline comments.
-  bool has_line_terminator_before_next_;
-  // Whether there is a multi-line comment that contains a
-  // line-terminator after the current token, and before the next.
-  bool has_multiline_comment_before_next_;
+  // the current token, and  before the next.
+  bool has_preceding_line_terminator_;
+  bool next_has_preceding_line_terminator_;
+
+  bool has_preceding_multiline_comment_;
 
   // Whether this scanner encountered an HTML comment.
   bool found_html_comment_;
 
   bool allow_harmony_exponentiation_operator_;
 
   MessageTemplate::Template scanner_error_;
   Location scanner_error_location_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PARSING_SCANNER_H_