Introduce "expression classifier" to the parser.

src/preparser.cc

 // 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.
 
 #include <cmath>
 
 #include "src/allocation.h"
 #include "src/base/logging.h"
 #include "src/conversions-inl.h"
 #include "src/conversions.h"
@@ skipping 502 matching lines @@
   do {
     // Parse variable name.
     if (nvars > 0) Consume(Token::COMMA);
     ParseIdentifier(kDontAllowRestrictedIdentifiers, CHECK_OK);
     Scanner::Location variable_loc = scanner()->location();
     nvars++;
     if (peek() == Token::ASSIGN || require_initializer ||
         // require initializers for multiple consts.
         (is_strict_const && peek() == Token::COMMA)) {
       Expect(Token::ASSIGN, CHECK_OK);
-      ParseAssignmentExpression(var_context != kForStatement, CHECK_OK);
+      ExpressionClassifier classifier;
+      ParseAssignmentExpression(var_context != kForStatement, &classifier,
+                                CHECK_OK);
+      // TODO(dslomov): report error if not valid expression.
 
       variable_loc.end_pos = scanner()->location().end_pos;
       if (first_initializer_loc && !first_initializer_loc->IsValid()) {
         *first_initializer_loc = variable_loc;
       }
     }
   } while (peek() == Token::COMMA);
 
   if (bindings_loc) {
     *bindings_loc =
@@ skipping 18 matching lines @@
       ReportUnexpectedToken(Next());
       *ok = false;
       return Statement::Default();
 
     case Token::THIS:
     case Token::SUPER:
       if (is_strong(language_mode()) &&
           i::IsConstructor(function_state_->kind())) {
         bool is_this = peek() == Token::THIS;
         Expression expr = Expression::Default();
+        ExpressionClassifier classifier;
         if (is_this) {
-          expr = ParseStrongInitializationExpression(CHECK_OK);
+          expr = ParseStrongInitializationExpression(&classifier, CHECK_OK);
         } else {
-          expr = ParseStrongSuperCallExpression(CHECK_OK);
+          expr = ParseStrongSuperCallExpression(&classifier, CHECK_OK);
         }
+        // TODO(dslomov): report error if not a valid expression.
         switch (peek()) {
           case Token::SEMICOLON:
             Consume(Token::SEMICOLON);
             break;
           case Token::RBRACE:
           case Token::EOS:
             break;
           default:
             if (!scanner()->HasAnyLineTerminatorBeforeNext()) {
               ReportMessageAt(function_state_->this_location(),
                               is_this ? "strong_constructor_this"
                                       : "strong_constructor_super");
               *ok = false;
               return Statement::Default();
             }
         }
         return Statement::ExpressionStatement(expr);
       }
       break;
 
     // TODO(arv): Handle `let [`
     // https://code.google.com/p/v8/issues/detail?id=3847
 
     default:
       break;
   }
 
   bool starts_with_identifier = peek_any_identifier();
-  Expression expr = ParseExpression(true, CHECK_OK);
+  ExpressionClassifier classifier;
+  Expression expr = ParseExpression(true, &classifier, CHECK_OK);
+  // TODO(dslomov): report error if not a valid expression.
+
   // Even if the expression starts with an identifier, it is not necessarily an
   // identifier. For example, "foo + bar" starts with an identifier but is not
   // an identifier.
   if (starts_with_identifier && expr.IsIdentifier() && peek() == Token::COLON) {
     // Expression is a single identifier, and not, e.g., a parenthesized
     // identifier.
     DCHECK(!expr.AsIdentifier().IsFutureReserved());
     DCHECK(is_sloppy(language_mode()) ||
            !IsFutureStrictReserved(expr.AsIdentifier()));
     Consume(Token::COLON);
@@ skipping 468 matching lines @@
 
   Scope* scope = NewScope(scope_, BLOCK_SCOPE);
   BlockState block_state(&scope_, scope);
   scope_->SetLanguageMode(
       static_cast<LanguageMode>(class_language_mode | STRICT_BIT));
   // TODO(marja): Make PreParser use scope names too.
   // scope_->SetScopeName(name);
 
   bool has_extends = Check(Token::EXTENDS);
   if (has_extends) {
-    ParseLeftHandSideExpression(CHECK_OK);
+    ExpressionClassifier classifier;
+    ParseLeftHandSideExpression(&classifier, CHECK_OK);
+    // TODO(dslomov): report error if not a valid expression.
   }
 
   ClassLiteralChecker checker(this);
   bool has_seen_constructor = false;
 
   Expect(Token::LBRACE, CHECK_OK);
   while (peek() != Token::RBRACE) {
     if (Check(Token::SEMICOLON)) continue;
     const bool in_class = true;
     const bool is_static = false;
     bool is_computed_name = false;  // Classes do not care about computed
                                     // property names here.
+    ExpressionClassifier classifier;
     ParsePropertyDefinition(&checker, in_class, has_extends, is_static,
-                            &is_computed_name, &has_seen_constructor, CHECK_OK);
+                            &is_computed_name, &has_seen_constructor,
+                            &classifier, CHECK_OK);
+    // TODO(dslomov): report error if not a valid expression.
   }
 
   Expect(Token::RBRACE, CHECK_OK);
 
   return Expression::Default();
 }
 
 
 PreParser::Expression PreParser::ParseV8Intrinsic(bool* ok) {
   // CallRuntime ::
   //   '%' Identifier Arguments
   Expect(Token::MOD, CHECK_OK);
   if (!allow_natives()) {
     *ok = false;
     return Expression::Default();
   }
   // Allow "eval" or "arguments" for backward compatibility.
   ParseIdentifier(kAllowRestrictedIdentifiers, CHECK_OK);
   Scanner::Location spread_pos;
-  ParseArguments(&spread_pos, ok);
+  ExpressionClassifier classifier;
+  ParseArguments(&spread_pos, &classifier, ok);
+  // TODO(dslomov): report error if not a valid expression.
 
   DCHECK(!spread_pos.IsValid());
 
   return Expression::Default();
 }
 
 #undef CHECK_OK
 
 
 } }  // v8::internal