[parser] Remove unused PreParserIdentifier types and support code

Also remove a few bits of related dead code in Parser.

Bug: v8:6092
Change-Id: I310936341fe3e6193e36983723985a190d5d278b
Reviewed-on: https://chromium-review.googlesource.com/621958
Commit-Queue: Adam Klein <adamk@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47518}

src/parsing/parser.h

@@ -622,10 +622,6 @@ class V8_EXPORT_PRIVATE Parser : public NON_EXPORTED_BASE(ParserBase<Parser>) {
     return IsEval(identifier) || IsArguments(identifier);
   }
 
-  V8_INLINE bool IsUndefined(const AstRawString* identifier) const {
-    return identifier == ast_value_factory()->undefined_string();
-  }
-
   // Returns true if the expression is of type "this.foo".
   V8_INLINE static bool IsThisProperty(Expression* expression) {
     DCHECK(expression != NULL);
@@ -653,10 +649,6 @@ class V8_EXPORT_PRIVATE Parser : public NON_EXPORTED_BASE(ParserBase<Parser>) {
     return expression->AsVariableProxy();
   }
 
-  V8_INLINE bool IsPrototype(const AstRawString* identifier) const {
-    return identifier == ast_value_factory()->prototype_string();
-  }
-
   V8_INLINE bool IsConstructor(const AstRawString* identifier) const {
     return identifier == ast_value_factory()->constructor_string();
   }

src/parsing/preparser.cc

@@ -43,30 +43,18 @@ namespace {
 
 PreParserIdentifier GetSymbolHelper(Scanner* scanner) {
   // These symbols require slightly different treatement:
-  // - regular keywords (enum, await, etc.; treated in 1st switch.)
+  // - regular keywords (async, await, etc.; treated in 1st switch.)
   // - 'contextual' keywords (and may contain escaped; treated in 2nd switch.)
   // - 'contextual' keywords, but may not be escaped (3rd switch).
   switch (scanner->current_token()) {
-    case Token::ENUM:
-      return PreParserIdentifier::Enum();
     case Token::AWAIT:
       return PreParserIdentifier::Await();
-    case Token::FUTURE_STRICT_RESERVED_WORD:
-      return PreParserIdentifier::FutureStrictReserved();
-    case Token::LET:
-      return PreParserIdentifier::Let();
-    case Token::STATIC:
-      return PreParserIdentifier::Static();
-    case Token::YIELD:
-      return PreParserIdentifier::Yield();
     case Token::ASYNC:
       return PreParserIdentifier::Async();
     default:
       break;
   }
   switch (scanner->current_contextual_token()) {
-    case Token::PROTOTYPE:
-      return PreParserIdentifier::Prototype();
     case Token::CONSTRUCTOR:
       return PreParserIdentifier::Constructor();
     case Token::NAME:
@@ -74,15 +62,14 @@ PreParserIdentifier GetSymbolHelper(Scanner* scanner) {
     default:
       break;
   }
-  if (scanner->literal_contains_escapes())
+  if (scanner->literal_contains_escapes()) {
     return PreParserIdentifier::Default();
+  }
   switch (scanner->current_contextual_token()) {
     case Token::EVAL:
       return PreParserIdentifier::Eval();
     case Token::ARGUMENTS:
       return PreParserIdentifier::Arguments();
-    case Token::UNDEFINED:
-      return PreParserIdentifier::Undefined();
     default:
       break;
   }

src/parsing/preparser.h

@@ -39,33 +39,9 @@ class PreParserIdentifier {
   static PreParserIdentifier Arguments() {
     return PreParserIdentifier(kArgumentsIdentifier);
   }
-  static PreParserIdentifier Undefined() {
-    return PreParserIdentifier(kUndefinedIdentifier);
-  }
-  static PreParserIdentifier FutureReserved() {
-    return PreParserIdentifier(kFutureReservedIdentifier);
-  }
-  static PreParserIdentifier FutureStrictReserved() {
-    return PreParserIdentifier(kFutureStrictReservedIdentifier);
-  }
-  static PreParserIdentifier Let() {
-    return PreParserIdentifier(kLetIdentifier);
-  }
-  static PreParserIdentifier Static() {
-    return PreParserIdentifier(kStaticIdentifier);
-  }
-  static PreParserIdentifier Yield() {
-    return PreParserIdentifier(kYieldIdentifier);
-  }
-  static PreParserIdentifier Prototype() {
-    return PreParserIdentifier(kPrototypeIdentifier);
-  }
   static PreParserIdentifier Constructor() {
     return PreParserIdentifier(kConstructorIdentifier);
   }
-  static PreParserIdentifier Enum() {
-    return PreParserIdentifier(kEnumIdentifier);
-  }
   static PreParserIdentifier Await() {
     return PreParserIdentifier(kAwaitIdentifier);
   }
@@ -79,39 +55,17 @@ class PreParserIdentifier {
   bool IsEval() const { return type_ == kEvalIdentifier; }
   bool IsArguments() const { return type_ == kArgumentsIdentifier; }
   bool IsEvalOrArguments() const { return IsEval() || IsArguments(); }
-  bool IsUndefined() const { return type_ == kUndefinedIdentifier; }
-  bool IsLet() const { return type_ == kLetIdentifier; }
-  bool IsStatic() const { return type_ == kStaticIdentifier; }
-  bool IsYield() const { return type_ == kYieldIdentifier; }
-  bool IsPrototype() const { return type_ == kPrototypeIdentifier; }
   bool IsConstructor() const { return type_ == kConstructorIdentifier; }
-  bool IsEnum() const { return type_ == kEnumIdentifier; }
   bool IsAwait() const { return type_ == kAwaitIdentifier; }
   bool IsName() const { return type_ == kNameIdentifier; }
 
-  // Allow identifier->name()[->length()] to work. The preparser
-  // does not need the actual positions/lengths of the identifiers.
-  const PreParserIdentifier* operator->() const { return this; }
-  const PreParserIdentifier raw_name() const { return *this; }
-
-  int position() const { return 0; }
-  int length() const { return 0; }
-
  private:
   enum Type {
     kNullIdentifier,
     kUnknownIdentifier,
-    kFutureReservedIdentifier,
-    kFutureStrictReservedIdentifier,
-    kLetIdentifier,
-    kStaticIdentifier,
-    kYieldIdentifier,
     kEvalIdentifier,
     kArgumentsIdentifier,
-    kUndefinedIdentifier,
-    kPrototypeIdentifier,
     kConstructorIdentifier,
-    kEnumIdentifier,
     kAwaitIdentifier,
     kAsyncIdentifier,
     kNameIdentifier
@@ -1051,7 +1005,6 @@ class PreParser : public ParserBase<PreParser> {
   V8_INLINE ZoneList<const AstRawString*>* DeclareLabel(
       ZoneList<const AstRawString*>* labels, PreParserExpression expr,
       bool* ok) {
-    DCHECK(!expr.AsIdentifier().IsEnum());
     DCHECK(!parsing_module_ || !expr.AsIdentifier().IsAwait());
     DCHECK(IsIdentifier(expr));
     return labels;
@@ -1224,10 +1177,6 @@ class PreParser : public ParserBase<PreParser> {
     return identifier.IsEvalOrArguments();
   }
 
-  V8_INLINE bool IsUndefined(PreParserIdentifier identifier) const {
-    return identifier.IsUndefined();
-  }
-
   V8_INLINE bool IsAwait(PreParserIdentifier identifier) const {
     return identifier.IsAwait();
   }
@@ -1251,10 +1200,6 @@ class PreParser : public ParserBase<PreParser> {
     return expression;
   }
 
-  V8_INLINE bool IsPrototype(PreParserIdentifier identifier) const {
-    return identifier.IsPrototype();
-  }
-
   V8_INLINE bool IsConstructor(PreParserIdentifier identifier) const {
     return identifier.IsConstructor();
   }