new classes: assert that constructors are not callable and rewrite 'return;'

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 280 matching lines @@
   function_scope->SetLanguageMode(
       static_cast<LanguageMode>(scope->language_mode() | STRICT));
   // Set start and end position to the same value
   function_scope->set_start_position(pos);
   function_scope->set_end_position(pos);
   ZoneList<Statement*>* body = NULL;
 
   {
     AstNodeFactory function_factory(ast_value_factory());
     FunctionState function_state(&function_state_, &scope_, function_scope,
-                                 &function_factory);
+                                 kDefaultConstructor, &function_factory);
 
     body = new (zone()) ZoneList<Statement*>(1, zone());
     if (call_super) {
       ZoneList<Expression*>* args =
           new (zone()) ZoneList<Expression*>(0, zone());
       CallRuntime* call = factory()->NewCallRuntime(
           ast_value_factory()->empty_string(),
           Runtime::FunctionForId(Runtime::kDefaultConstructorSuperCall), args,
           pos);
       body->Add(factory()->NewExpressionStatement(call, pos), zone());
@@ skipping 626 matching lines @@
     Mode mode = (FLAG_lazy && allow_lazy()) ? PARSE_LAZILY : PARSE_EAGERLY;
     if (allow_natives() || extension_ != NULL ||
         (*scope)->is_eval_scope()) {
       mode = PARSE_EAGERLY;
     }
     ParsingModeScope parsing_mode(this, mode);
 
     // Enters 'scope'.
     AstNodeFactory function_factory(ast_value_factory());
     FunctionState function_state(&function_state_, &scope_, *scope,
-                                 &function_factory);
+                                 kNormalFunction, &function_factory);
 
     scope_->SetLanguageMode(info->language_mode());
     ZoneList<Statement*>* body = new(zone()) ZoneList<Statement*>(16, zone());
     bool ok = true;
     int beg_pos = scanner()->location().beg_pos;
     if (info->is_module()) {
       DCHECK(allow_harmony_modules());
       Module* module = ParseModule(&ok);
       if (ok) {
         // TODO(adamk): Do something with returned Module
@@ skipping 99 matching lines @@
     // Parse the function literal.
     Scope* scope = NewScope(scope_, SCRIPT_SCOPE);
     info()->SetScriptScope(scope);
     if (!info()->closure().is_null()) {
       scope = Scope::DeserializeScopeChain(isolate(), zone(),
                                            info()->closure()->context(), scope);
     }
     original_scope_ = scope;
     AstNodeFactory function_factory(ast_value_factory());
     FunctionState function_state(&function_state_, &scope_, scope,
-                                 &function_factory);
+                                 shared_info->kind(), &function_factory);
     DCHECK(is_sloppy(scope->language_mode()) ||
            is_strict(info()->language_mode()));
     DCHECK(info()->language_mode() == shared_info->language_mode());
     scope->SetLanguageMode(shared_info->language_mode());
     FunctionLiteral::FunctionType function_type = shared_info->is_expression()
         ? (shared_info->is_anonymous()
               ? FunctionLiteral::ANONYMOUS_EXPRESSION
               : FunctionLiteral::NAMED_EXPRESSION)
         : FunctionLiteral::DECLARATION;
     bool ok = true;
@@ skipping 1549 matching lines @@
   Expect(Token::RETURN, CHECK_OK);
   Scanner::Location loc = scanner()->location();
 
   Token::Value tok = peek();
   Statement* result;
   Expression* return_value;
   if (scanner()->HasAnyLineTerminatorBeforeNext() ||
       tok == Token::SEMICOLON ||
       tok == Token::RBRACE ||
       tok == Token::EOS) {
-    return_value = GetLiteralUndefined(position());
+    if (FLAG_experimental_classes &&
+        IsSubclassConstructor(function_state_->kind())) {
+      return_value = ThisExpression(scope_, factory(), loc.beg_pos);
+    } else {
+      return_value = GetLiteralUndefined(position());
+    }
   } else {
     return_value = ParseExpression(true, CHECK_OK);
   }
   ExpectSemicolon(CHECK_OK);
+
   if (is_generator()) {
     Expression* generator = factory()->NewVariableProxy(
         function_state_->generator_object_variable());
     Expression* yield = factory()->NewYield(
         generator, return_value, Yield::kFinal, loc.beg_pos);
     result = factory()->NewExpressionStatement(yield, loc.beg_pos);
   } else {
     result = factory()->NewReturnStatement(return_value, loc.beg_pos);
   }
 
@@ skipping 996 matching lines @@
   int expected_property_count = -1;
   int handler_count = 0;
   FunctionLiteral::ParameterFlag duplicate_parameters =
       FunctionLiteral::kNoDuplicateParameters;
   FunctionLiteral::IsParenthesizedFlag parenthesized = parenthesized_function_
       ? FunctionLiteral::kIsParenthesized
       : FunctionLiteral::kNotParenthesized;
   // Parse function body.
   {
     AstNodeFactory function_factory(ast_value_factory());
-    FunctionState function_state(&function_state_, &scope_, scope,
+    FunctionState function_state(&function_state_, &scope_, scope, kind,
                                  &function_factory);
     scope_->SetScopeName(function_name);
 
     if (is_generator) {
       // For generators, allocating variables in contexts is currently a win
       // because it minimizes the work needed to suspend and resume an
       // activation.
       scope_->ForceContextAllocation();
 
       // Calling a generator returns a generator object.  That object is stored
@@ skipping 133 matching lines @@
     bool is_lazily_parsed = (mode() == PARSE_LAZILY &&
                              scope_->AllowsLazyCompilation() &&
                              !parenthesized_function_);
     parenthesized_function_ = false;  // The bit was set for this function only.
 
     if (is_lazily_parsed) {
       SkipLazyFunctionBody(function_name, &materialized_literal_count,
                            &expected_property_count, CHECK_OK);
     } else {
       body = ParseEagerFunctionBody(function_name, pos, fvar, fvar_init_op,
-                                    is_generator, CHECK_OK);
+                                    kind, CHECK_OK);
       materialized_literal_count = function_state.materialized_literal_count();
       expected_property_count = function_state.expected_property_count();
       handler_count = function_state.handler_count();
     }
 
     // Validate strict mode.
     // Concise methods use StrictFormalParameters.
     // Functions for which IsSimpleParameterList() returns false use
     // StrictFormalParameters.
     if (is_strict(language_mode()) || IsConciseMethod(kind) || is_rest) {
@@ skipping 89 matching lines @@
     // Position right after terminal '}'.
     int body_end = scanner()->location().end_pos;
     log_->LogFunction(function_block_pos, body_end, *materialized_literal_count,
                       *expected_property_count, scope_->language_mode());
   }
 }
 
 
 ZoneList<Statement*>* Parser::ParseEagerFunctionBody(
     const AstRawString* function_name, int pos, Variable* fvar,
-    Token::Value fvar_init_op, bool is_generator, bool* ok) {
+    Token::Value fvar_init_op, FunctionKind kind, bool* ok) {
   // Everything inside an eagerly parsed function will be parsed eagerly
   // (see comment above).
   ParsingModeScope parsing_mode(this, PARSE_EAGERLY);
   ZoneList<Statement*>* body = new(zone()) ZoneList<Statement*>(8, zone());
   if (fvar != NULL) {
     VariableProxy* fproxy = scope_->NewUnresolved(
         factory(), function_name, Interface::NewConst());
     fproxy->BindTo(fvar);
     body->Add(factory()->NewExpressionStatement(
         factory()->NewAssignment(fvar_init_op,
                                  fproxy,
                                  factory()->NewThisFunction(pos),
                                  RelocInfo::kNoPosition),
         RelocInfo::kNoPosition), zone());
   }
 
+
+  // For concise constructors, check that they are constructed,
+  // not called.
+  if (FLAG_experimental_classes && i::IsConstructor(kind)) {
+    ZoneList<Expression*>* arguments =
+        new (zone()) ZoneList<Expression*>(0, zone());
+    CallRuntime* construct_check = factory()->NewCallRuntime(
+        ast_value_factory()->is_construct_call_string(),
+        Runtime::FunctionForId(Runtime::kInlineIsConstructCall), arguments,
+        pos);
+    CallRuntime* non_callable_error = factory()->NewCallRuntime(
+        ast_value_factory()->empty_string(),
+        Runtime::FunctionForId(Runtime::kThrowConstructorNonCallableError),
+        arguments, pos);
+    IfStatement* if_statement = factory()->NewIfStatement(
+        factory()->NewUnaryOperation(Token::NOT, construct_check, pos),
+        factory()->NewReturnStatement(non_callable_error, pos),
+        factory()->NewEmptyStatement(pos), pos);
+    body->Add(if_statement, zone());
+  }
+
   // For generators, allocate and yield an iterator on function entry.
-  if (is_generator) {
+  if (IsGeneratorFunction(kind)) {
     ZoneList<Expression*>* arguments =
         new(zone()) ZoneList<Expression*>(0, zone());
     CallRuntime* allocation = factory()->NewCallRuntime(
         ast_value_factory()->empty_string(),
         Runtime::FunctionForId(Runtime::kCreateJSGeneratorObject), arguments,
         pos);
     VariableProxy* init_proxy = factory()->NewVariableProxy(
         function_state_->generator_object_variable());
     Assignment* assignment = factory()->NewAssignment(
         Token::INIT_VAR, init_proxy, allocation, RelocInfo::kNoPosition);
     VariableProxy* get_proxy = factory()->NewVariableProxy(
         function_state_->generator_object_variable());
     Yield* yield = factory()->NewYield(
         get_proxy, assignment, Yield::kInitial, RelocInfo::kNoPosition);
     body->Add(factory()->NewExpressionStatement(
         yield, RelocInfo::kNoPosition), zone());
   }
 
   ParseStatementList(body, Token::RBRACE, false, NULL, CHECK_OK);
 
-  if (is_generator) {
+  if (IsGeneratorFunction(kind)) {
     VariableProxy* get_proxy = factory()->NewVariableProxy(
         function_state_->generator_object_variable());
     Expression* undefined =
         factory()->NewUndefinedLiteral(RelocInfo::kNoPosition);
     Yield* yield = factory()->NewYield(get_proxy, undefined, Yield::kFinal,
                                        RelocInfo::kNoPosition);
     body->Add(factory()->NewExpressionStatement(
         yield, RelocInfo::kNoPosition), zone());
   }
 
+  if (FLAG_experimental_classes && IsSubclassConstructor(kind)) {
+    body->Add(
+        factory()->NewReturnStatement(
+            this->ThisExpression(scope_, factory(), RelocInfo::kNoPosition),
+            RelocInfo::kNoPosition),
+        zone());
+  }
+
   Expect(Token::RBRACE, CHECK_OK);
   scope_->set_end_position(scanner()->location().end_pos);
 
   return body;
 }
 
 
 PreParser::PreParseResult Parser::ParseLazyFunctionBodyWithPreParser(
     SingletonLogger* logger) {
   // This function may be called on a background thread too; record only the
@@ skipping 19 matching lines @@
         allow_harmony_object_literals());
     reusable_preparser_->set_allow_harmony_templates(allow_harmony_templates());
     reusable_preparser_->set_allow_harmony_sloppy(allow_harmony_sloppy());
     reusable_preparser_->set_allow_harmony_unicode(allow_harmony_unicode());
     reusable_preparser_->set_allow_harmony_computed_property_names(
         allow_harmony_computed_property_names());
     reusable_preparser_->set_allow_harmony_rest_params(
         allow_harmony_rest_params());
   }
   PreParser::PreParseResult result = reusable_preparser_->PreParseLazyFunction(
-      language_mode(), is_generator(), logger);
+      language_mode(), function_state_->kind(), logger);
   if (pre_parse_timer_ != NULL) {
     pre_parse_timer_->Stop();
   }
   return result;
 }
 
 
 ClassLiteral* Parser::ParseClassLiteral(const AstRawString* name,
                                         Scanner::Location class_name_location,
                                         bool name_is_strict_reserved, int pos,
@@ skipping 1389 matching lines @@
     } else {
       const uc16* data = reinterpret_cast<const uc16*>(raw_string->raw_data());
       running_hash = StringHasher::ComputeRunningHash(running_hash, data,
                                                       raw_string->length());
     }
   }
 
   return running_hash;
 }
 } }  // namespace v8::internal