Fix scanner-level error reporting for hashbang

When the file begins with a hashbang, the scanner is in a failed state
when SkipHashbang() is called. This is usually not an issue but when
the parser encounters an ILLEGAL token, it will reset the SyntaxError
location because of it.

Bug: v8:10110
Change-Id: I1c7344bf5ad20079cff80130c991f3bff4d7e9a8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1995312Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66038}

src/parsing/parser.cc

@@ -505,7 +505,6 @@ FunctionLiteral* Parser::ParseProgram(Isolate* isolate, Handle<Script> script,
                         Scope::DeserializationMode::kIncludingVariables);
 
   scanner_.Initialize();
-  scanner_.SkipHashBang();
   FunctionLiteral* result = DoParseProgram(isolate, info);
   MaybeResetCharacterStream(info, result);
   MaybeProcessSourceRanges(info, result, stack_limit_);

src/parsing/preparser.cc

@@ -75,10 +75,6 @@ PreParser::PreParseResult PreParser::PreParseProgram() {
   scope->set_is_being_lazily_parsed(true);
 #endif
 
-  // Note: We should only skip the hashbang in non-Eval scripts
-  // (currently, Eval is not handled by the PreParser).
-  scanner()->SkipHashBang();
-
   // ModuleDeclarationInstantiation for Source Text Module Records creates a
   // new Module Environment Record whose outer lexical environment record is
   // the global scope.

src/parsing/scanner-inl.h

@@ -506,6 +506,10 @@ V8_INLINE Token::Value Scanner::ScanSingleToken() {
           return ScanTemplateSpan();
 
         case Token::PRIVATE_NAME:
+          if (source_pos() == 0 && Peek() == '!') {
+            token = SkipSingleLineComment();
+            continue;
+          }
           return ScanPrivateName();
 
         case Token::WHITESPACE:

src/parsing/scanner.cc

@@ -314,13 +314,6 @@ Token::Value Scanner::SkipMultiLineComment() {
   return Token::ILLEGAL;
 }
 
-void Scanner::SkipHashBang() {
-  if (c0_ == '#' && Peek() == '!' && source_pos() == 0) {
-    SkipSingleLineComment();
-    Scan();
-  }
-}
-
 Token::Value Scanner::ScanHtmlComment() {
   // Check for <!-- comments.
   DCHECK_EQ(c0_, '!');

src/parsing/scanner.h

@@ -422,9 +422,6 @@ class V8_EXPORT_PRIVATE Scanner {
 
   const Utf16CharacterStream* stream() const { return source_; }
 
-  // If the next characters in the stream are "#!", the line is skipped.
-  void SkipHashBang();
-
  private:
   // Scoped helper for saving & restoring scanner error state.
   // This is used for tagged template literals, in which normally forbidden

test/message/fail/hashbang-incomplete-string.js

+#!/usr/bin/env d8
+// Copyright 2015 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.
+//
+//
+
+const x = 'valid code';
+
+'incomplete string
+
+const y = 'even more valid code!';

test/message/fail/hashbang-incomplete-string.out

+*%(basename)s:10: SyntaxError: Invalid or unexpected token
+'incomplete string
+^^^^^^^^^^^^^^^^^^
+
+SyntaxError: Invalid or unexpected token