[parser] Correctly handle invalid escapes in adjacent template tokens.

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 197 matching lines @@
   // Returns the location information for the current token
   // (the token last returned by Next()).
   Location location() const { return current_.location; }
 
   // This error is specifically an invalid hex or unicode escape sequence.
   bool has_error() const { return scanner_error_ != MessageTemplate::kNone; }
   MessageTemplate::Template error() const { return scanner_error_; }
   Location error_location() const { return scanner_error_location_; }
 
   bool has_invalid_template_escape() const {
-    return invalid_template_escape_message_ != MessageTemplate::kNone;
+    return current_.invalid_template_escape_message != MessageTemplate::kNone;
   }
   MessageTemplate::Template invalid_template_escape_message() const {
-    return invalid_template_escape_message_;
+    DCHECK(has_invalid_template_escape());
+    return current_.invalid_template_escape_message;
   }
   Location invalid_template_escape_location() const {
-    return invalid_template_escape_location_;
-  }
-
-  void clear_invalid_template_escape() {
     DCHECK(has_invalid_template_escape());
-    invalid_template_escape_message_ = MessageTemplate::kNone;
-    invalid_template_escape_location_ = Location::invalid();
+    return current_.invalid_template_escape_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; }
 
   bool literal_contains_escapes() const {
@@ skipping 97 matching lines @@
   Handle<String> SourceMappingUrl(Isolate* isolate) const {
     Handle<String> tmp;
     if (source_mapping_url_.length() > 0)
       tmp = source_mapping_url_.Internalize(isolate);
     return tmp;
   }
 
   bool FoundHtmlComment() const { return found_html_comment_; }
 
  private:
+  // Scoped helper for saving & restoring scanner error state.
+  // This is used for tagged template literals, in which normally forbidden
+  // escape sequences are allowed.
+  class ErrorState;
+
   // Scoped helper for literal recording. Automatically drops the literal
   // if aborting the scanning before it's complete.
   class LiteralScope {
    public:
     explicit LiteralScope(Scanner* self) : scanner_(self), complete_(false) {
       scanner_->StartLiteral();
     }
     ~LiteralScope() {
       if (!complete_) scanner_->DropLiteral();
     }
@@ skipping 92 matching lines @@
     DISALLOW_COPY_AND_ASSIGN(LiteralBuffer);
   };
 
   // The current and look-ahead token.
   struct TokenDesc {
     Location location;
     LiteralBuffer* literal_chars;
     LiteralBuffer* raw_literal_chars;
     uint32_t smi_value_;
     Token::Value token;
+    MessageTemplate::Template invalid_template_escape_message;
+    Location invalid_template_escape_location;
   };
 
   static const int kCharacterLookaheadBufferSize = 1;
   const int kMaxAscii = 127;
 
   // Scans octal escape sequence. Also accepts "\0" decimal escape sequence.
   template <bool capture_raw>
   uc32 ScanOctalEscape(uc32 c, int length);
 
   // Call this after setting source_ to the input.
   void Init() {
     // Set c0_ (one character ahead)
     STATIC_ASSERT(kCharacterLookaheadBufferSize == 1);
     Advance();
     // Initialize current_ to not refer to a literal.
     current_.token = Token::UNINITIALIZED;
     current_.literal_chars = NULL;
     current_.raw_literal_chars = NULL;
+    current_.invalid_template_escape_message = MessageTemplate::kNone;
     next_.token = Token::UNINITIALIZED;
     next_.literal_chars = NULL;
     next_.raw_literal_chars = NULL;
+    next_.invalid_template_escape_message = MessageTemplate::kNone;
     next_next_.token = Token::UNINITIALIZED;
     next_next_.literal_chars = NULL;
     next_next_.raw_literal_chars = NULL;
+    next_next_.invalid_template_escape_message = MessageTemplate::kNone;
     found_html_comment_ = false;
     scanner_error_ = MessageTemplate::kNone;
-    invalid_template_escape_message_ = MessageTemplate::kNone;
   }
 
   void ReportScannerError(const Location& location,
                           MessageTemplate::Template error) {
     if (has_error()) return;
     scanner_error_ = error;
     scanner_error_location_ = location;
   }
 
   void ReportScannerError(int pos, MessageTemplate::Template error) {
@@ skipping 270 matching lines @@
   // 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_;
   bool has_line_terminator_after_next_;
 
   // Whether this scanner encountered an HTML comment.
   bool found_html_comment_;
 
   MessageTemplate::Template scanner_error_;
   Location scanner_error_location_;
-
-  MessageTemplate::Template invalid_template_escape_message_;
-  Location invalid_template_escape_location_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PARSING_SCANNER_H_