Introduce "expression classifier" to the parser.

src/parser.cc

 // Copyright 2012 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 "src/v8.h"
 
 #include "src/api.h"
 #include "src/ast.h"
 #include "src/bailout-reason.h"
 #include "src/base/platform/platform.h"
@@ skipping 1593 matching lines @@
       result = ParseFunctionDeclaration(&names, CHECK_OK);
       break;
 
     case Token::CLASS:
       // TODO(ES6): Support parsing anonymous class declarations here.
       result = ParseClassDeclaration(&names, CHECK_OK);
       break;
 
     default: {
       int pos = peek_position();
-      Expression* expr = ParseAssignmentExpression(true, CHECK_OK);
+      ExpressionClassifier classifier;
+      Expression* expr = ParseAssignmentExpression(true, &classifier, CHECK_OK);
+      // TODO(dslomov): report error if not a valid expression.
+
       ExpectSemicolon(CHECK_OK);
       result = factory()->NewExpressionStatement(expr, pos);
       break;
     }
   }
 
   const AstRawString* default_string = ast_value_factory()->default_string();
 
   DCHECK_LE(names.length(), 1);
   if (names.length() == 1) {
@@ skipping 793 matching lines @@
     // Declare() call above).
 
     Scope* initialization_scope = is_const ? declaration_scope : scope_;
     Expression* value = NULL;
     int pos = -1;
     // Harmony consts have non-optional initializers.
     if (peek() == Token::ASSIGN ||
         (mode == CONST && !is_for_iteration_variable)) {
       Expect(Token::ASSIGN, CHECK_OK);
       pos = position();
-      value = ParseAssignmentExpression(var_context != kForStatement, CHECK_OK);
+      ExpressionClassifier classifier;
+      value = ParseAssignmentExpression(var_context != kForStatement,
+                                        &classifier, CHECK_OK);
+      // TODO(dslomov): check that expression is valid.
       variable_loc.end_pos = scanner()->location().end_pos;
 
       if (first_initializer_loc && !first_initializer_loc->IsValid()) {
         *first_initializer_loc = variable_loc;
       }
 
       // Don't infer if it is "a = function(){...}();"-like expression.
       if (fni_ != NULL &&
           value->AsCall() == NULL &&
           value->AsCallNew() == NULL) {
@@ skipping 1891 matching lines @@
   if (name != NULL) {
     proxy = NewUnresolved(name, CONST);
     Declaration* declaration =
         factory()->NewVariableDeclaration(proxy, CONST, block_scope, pos);
     Declare(declaration, true, CHECK_OK);
   }
 
   Expression* extends = NULL;
   if (Check(Token::EXTENDS)) {
     block_scope->set_start_position(scanner()->location().end_pos);
-    extends = ParseLeftHandSideExpression(CHECK_OK);
+    ExpressionClassifier classifier;
+    extends = ParseLeftHandSideExpression(&classifier, CHECK_OK);
+    // TODO(dslomov): report error if not a valid expression.
   } else {
     block_scope->set_start_position(scanner()->location().end_pos);
   }
 
 
   ClassLiteralChecker checker(this);
   ZoneList<ObjectLiteral::Property*>* properties = NewPropertyList(4, zone());
   FunctionLiteral* constructor = NULL;
   bool has_seen_constructor = false;
 
   Expect(Token::LBRACE, CHECK_OK);
 
   const bool has_extends = extends != nullptr;
   while (peek() != Token::RBRACE) {
     if (Check(Token::SEMICOLON)) continue;
     if (fni_ != NULL) fni_->Enter();
     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;
     ObjectLiteral::Property* property = ParsePropertyDefinition(
         &checker, in_class, has_extends, is_static, &is_computed_name,
-        &has_seen_constructor, CHECK_OK);
+        &has_seen_constructor, &classifier, CHECK_OK);
+    // TODO(dslomov): report error if not a valid expression.
 
     if (has_seen_constructor && constructor == NULL) {
       constructor = GetPropertyValue(property)->AsFunctionLiteral();
       DCHECK_NOT_NULL(constructor);
     } else {
       properties->Add(property, zone());
     }
 
     if (fni_ != NULL) {
       fni_->Infer();
@@ skipping 28 matching lines @@
 Expression* Parser::ParseV8Intrinsic(bool* ok) {
   // CallRuntime ::
   //   '%' Identifier Arguments
 
   int pos = peek_position();
   Expect(Token::MOD, CHECK_OK);
   // Allow "eval" or "arguments" for backward compatibility.
   const AstRawString* name = ParseIdentifier(kAllowRestrictedIdentifiers,
                                              CHECK_OK);
   Scanner::Location spread_pos;
-  ZoneList<Expression*>* args = ParseArguments(&spread_pos, CHECK_OK);
+  ExpressionClassifier classifier;
+  ZoneList<Expression*>* args =
+      ParseArguments(&spread_pos, &classifier, CHECK_OK);
+  // TODO(dslomov): report error if not a valid expression.
 
   DCHECK(!spread_pos.IsValid());
 
   if (extension_ != NULL) {
     // The extension structures are only accessible while parsing the
     // very first time not when reparsing because of lazy compilation.
     scope_->DeclarationScope()->ForceEagerCompilation();
   }
 
   const Runtime::Function* function = Runtime::FunctionForName(name->string());
@@ skipping 1356 matching lines @@
 
 Expression* Parser::SpreadCallNew(Expression* function,
                                   ZoneList<v8::internal::Expression*>* args,
                                   int pos) {
   args->InsertAt(0, function, zone());
 
   return factory()->NewCallRuntime(
       ast_value_factory()->reflect_construct_string(), NULL, args, pos);
 }
 } }  // namespace v8::internal